aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/char/synclink.c
blob: 813552f14884427ea785b1ac0e2bec080c704a6a (plain) (tree)
1
2
3
4
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479


                                
                                                          




























































                                                                         















                            
                           
                       
                           
                        
                            

                          
                        
                           









                            
                              
 



                                                                                            








                                                                                               


















                                                                            

                           




                                                                         


                                                            



                                                                    
                            









                                             
























                                        
                                     

                                           


                                       

                                                                        






                                                        














                                                                                         
                                                                      
                         
                          






                                                                                     

                                        



















                                                                                          


                             
 

                        












                                                                               
                                                                           


                                                             
                                                                   

                                                         
                                                                           








                                                                          
                                                                 





                                                                                                  
                                  



                                                                               
                               



                                                
                                 
 

                                          




                                                            

                           
                         






















































































































































































































































































































































































































                                                                                                     
                         



























                                                                                             



                                                           













                                                                                                                   

                                                              


















                                                                                                            
                                                                  




                                                                                                        
                                                      
















































                                                                                        
                           



























                                                               









                                           



                                                    
                                                  








































                                                                                          








































                                                                         

                                                                      










                                                             
                                                    





















                                                                
                                                    









































                                                                  

                                           









                                                                   
                                                     
 

                                                             








                                                             
                                
































                                                                                 
                                                        



















                                                                                                  
                                                





                                                                  
                
                                











































                                                                      
                                                        




































































                                                                            
                                








                                                                  
                                                  

         
                         




                                      
                                                                            

























































                                                                            
                         





                                                                        














                                                                            
                                                            




                                                                                 
                                                                             


                                                                         

                                                                   


                         
                                                            
                                                          
                                                         


                                                                             

                                                                               







                                                                             

                                                                               












                                                                                                        
                                          


















                                                                     
                                                                    






                                           
                                        


















                                                                       
                     
                               
                                                

















                                                                                       

                         










                                                                               

                             
                         
























                                                                                                        
                                                 
                                                                 

                                                                  
                                                  
                                                                 
                                                 
                                               







                                                                          


                                               




                                                                             
                




                                          
                                                 























                                                                                   
                                             
























































                                                                                   
                                         
































































                                                                          


                     
                                                          
 
                                          



                                                

                                                                      
 






















                                                                                         

                                                                                        














                                                                             
                                          




                                                


                                                                     
















                                                                                        
                                                 













                                                                                    

                                                       
                                                                           








                                                     

                                                                      






                                                     

                                                                
 
                                              















                                                                
                                                    










                                                                
                                        























                                                                                  
                                                                          







                                                                               

                                                              
 
                                               






























                                                                                
                                                                       











                                                          
                                                        





                                                                
                                                 














































                                                                               
                                                                           







                                                                     
                                                   
            
                                                    

                           
                                                    
            
                                                   



                                                  
                                    
                                                                                         
                                                                 

                                                                  
                                     
                                                                                           
                                       



                                                                    
                                             















                                                                     
                                                                  
 
                                                    
                            
                    
 
                                              
                                                                     
                                                                   


                                                                  
                         

                                    
                         
 
                                                      
        
                                                                          



                                                               
                                

                 
                                                           
                   












                                                                    
                                                    


















































                                                                                       
                                                    








                                                                   
                                    















































































































                                                                                         
                                                    

































                                                                    
                                                    
































                                                                               
                                                    













                                                                      












                                                             
                                                    



























                                                                     
                                                    




























                                                                            
                                                    









































                                                                                            





                                                                                          



















































































































































































































































































































































































































                                                                                              
                                                    
























                                                                            
                                                    

























                                                                         
                                  
   
                                                              
 
                                                     






                                                                            
                               






                                                                          
                 
















                                                                 
                                                     
                













                                                                            



                                                























































































                                                                                           
                                                                                  
 
                                                    





                                                                         














































                                                                               
                                                     





                                                                 
                                                                                 
 
                                                                                 

                             
                                                 
                                                         
                               
                             
                       

                                                
                              


                                                                                   
                                                             















                                                                     
                                                     











                                                                         
                                                    








                                                                 

                      




























                                                                                   
                        

















                                                                   
                                                     










                                                                


                                                 
 
                                                     


                                  
















                                                                                
                                                  




                                                                                



                                                                               




                                                          

















                                                                      

                                            
                              

                                            






                                                                            
                                                   



                                           
                                 


                                                                   
                                                            




                                                                      
                                                


                                                                              
                                                                             


                                                      
                                   
                              

                                                           
                             

                   

                                                     


                                                      

                                                                               



                                                               
                                                           
                
                                                                         
                              







                                                                                  
                                                                                     




                                        
                                                   
        
                                                     
                        

                              


                                                                                
                                                                             

                         
                                                   


















                                                                     

















                                                                   
                             


                                                                    
                                                                                

                                                            



                                                                       



                                                
                                                                                     






                                                              
                           

                                                      
                                    





















                                                                               


                                                                                      









                                
                                                                          

                             


                                                  
                                                                        


                                                                          
                                                                

























                                                          
                                                      

                                                                    
                                                                           
                                         
                                                                           
                                         
                                                                           
                                        
                                                                         
                                        
                                                                         
                                       
                                                                       
                
                                                   

                                                                
                                                                    
                                        
                                                                     
                                     
                                                                   
                                         
                                                                      


                                                
                                           
        
                                                                        















                                                             
                                                                           



                                                                                       
 
 

                                                      
 

                                 
                                                              


                                
                                   

                                         

                 
 











                                                                 



































































































































                                                                                                    

                                                                                                                      
                                       
                                                                           

































































                                                                                         

                                                                                                       

























                                                                                                       
                      










                                                                                           

                                                                                                                               
                                               
                                                                  





























                                                                                                         
                                                                                                                                
























































                                                                                          
                                           





























                                                                                                   




                                                                          
                                       
                 




















                                                                            

                                                          


















                                                             
                                                               
                                                     
                                       
   
                                                                 
 
                         






















                                                                                          
                                   












































                                                                                                       
                                       






                                                                               
                                   






                                                                                             
                                                  




                                                                                                             
                                               
 

                                                                           











                                                                                              

                                                                           




                                                                                           
                                                   









                                                                                        
                                           


























                                                                                 
                                            



                                             
                                            






                                                                 
                                                


                                                                   
                                                   


                                                                               
                                                
































                                                                     










































                                                                                                
                         




                                      

                                                         
                           


  










                                                                         
                                                  




                                                                      
                                           
                                                
                                         
                                                        
                                            

                                                 













                                                                          
                                               













                                                





                                        
                                     






















                                                      

                                                    



































































                                                                                  
                         







                                             


















                                                                                   
                                      































































































































































































                                                                                
                       











                                                                        
                                                  












































































































































































































































































































































































































































































































































































































































































































                                                                                                           


                                          
























                                                                              
                                                    
                                                      
                                                   









                                                                                 

                                                     













                                                                                        

                                                     
























                                                                                                         
                                     




































































                                                                                      


                                      





























































                                                                                      
                                

























                                                                          
                                                  





                                                                           
                                                                 



























































                                                                                                  

                                                                
                 
                                       


                                  
                                        






























                                                                         

                                 























































































































































































































































                                                                                               
                                                                          













































































































                                                                                      




                                                   


































































































































































































































































































































































































































                                                                                                                  
                          












                                                                          
                                    























                                                                              
                                                               
   
                                                       




                                                                                               
                                
                            
                                                
                                  

























































                                                                                  
                                                    

                              
                         
                 

                                                              


                 
                                    


































































                                                                                                   
                         









                                                                                                               
                          





































                                                                             
                                                               
   
                                                           




                                             
                                
                            
                                                

























































































































                                                                                                       
                                  











































































































                                                                                        
                                                                    
   
                                                          


                                                                                   
                                                                   
                       
                       









                                                       
                           

         
                  
















                                                                                                    
                                           














                                                               
                                                            
   
                                                     








                                                                         
                                             

           
                                   
























                                                                                           
                                  









                                                                      
                                                            
   
                                                     





                                 
                       















































































































                                                                                            
                                   






















































                                                                                             
                                   


















                                                                                         
                 


























                                                                                                    
                                           









                                                                          
                  

                                               
                                   

         
                   








                                                                             
                                           






                                                              
                   




                                                        
                                   


                                                                                 
                                           





























































                                                                                                 
                                                            
   
                                                        
 


                                                                                                




                                                                                
                            







                                                                
                                     













                                                               
                                     




                                                                
                    



















































































































                                                                                            
                                






                                                               
                         


















                                                                  
                                                                  












                                                               
                                                   




















                                                                              
                                               


















                                                                       
                         


















                                                                               
                             




















                                                                                    
                                            


















                                                                    












                                                                          

                                        






































                                                                   
                                                           


























                                                                                 



                                                    





















































                                                                            
                             
























































































                                                                                                                




                                                             

                                       































                                                                     

                                            
                                                      

                          


                                                                            


                       
                                              
 
                                                  
 

                                    

                      

 








                                                  


























                                                                                

                                           
































































                                                                                    
                                      























                                                                   
/*
 * linux/drivers/char/synclink.c
 *
 * $Id: synclink.c,v 4.38 2005/11/07 16:30:34 paulkf Exp $
 *
 * Device driver for Microgate SyncLink ISA and PCI
 * high speed multiprotocol serial adapters.
 *
 * written by Paul Fulghum for Microgate Corporation
 * paulkf@microgate.com
 *
 * Microgate and SyncLink are trademarks of Microgate Corporation
 *
 * Derived from serial.c written by Theodore Ts'o and Linus Torvalds
 *
 * Original release 01/11/99
 *
 * This code is released under the GNU General Public License (GPL)
 *
 * This driver is primarily intended for use in synchronous
 * HDLC mode. Asynchronous mode is also provided.
 *
 * When operating in synchronous mode, each call to mgsl_write()
 * contains exactly one complete HDLC frame. Calling mgsl_put_char
 * will start assembling an HDLC frame that will not be sent until
 * mgsl_flush_chars or mgsl_write is called.
 * 
 * Synchronous receive data is reported as complete frames. To accomplish
 * this, the TTY flip buffer is bypassed (too small to hold largest
 * frame and may fragment frames) and the line discipline
 * receive entry point is called directly.
 *
 * This driver has been tested with a slightly modified ppp.c driver
 * for synchronous PPP.
 *
 * 2000/02/16
 * Added interface for syncppp.c driver (an alternate synchronous PPP
 * implementation that also supports Cisco HDLC). Each device instance
 * registers as a tty device AND a network device (if dosyncppp option
 * is set for the device). The functionality is determined by which
 * device interface is opened.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#if defined(__i386__)
#  define BREAKPOINT() asm("   int $3");
#else
#  define BREAKPOINT() { }
#endif

#define MAX_ISA_DEVICES 10
#define MAX_PCI_DEVICES 10
#define MAX_TOTAL_DEVICES 20

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/synclink.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/dma.h>
#include <linux/bitops.h>
#include <asm/types.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/hdlc.h>
#include <linux/dma-mapping.h>

#if defined(CONFIG_HDLC) || (defined(CONFIG_HDLC_MODULE) && defined(CONFIG_SYNCLINK_MODULE))
#define SYNCLINK_GENERIC_HDLC 1
#else
#define SYNCLINK_GENERIC_HDLC 0
#endif

#define GET_USER(error,value,addr) error = get_user(value,addr)
#define COPY_FROM_USER(error,dest,src,size) error = copy_from_user(dest,src,size) ? -EFAULT : 0
#define PUT_USER(error,value,addr) error = put_user(value,addr)
#define COPY_TO_USER(error,dest,src,size) error = copy_to_user(dest,src,size) ? -EFAULT : 0

#include <asm/uaccess.h>

#define RCLRVALUE 0xffff

static MGSL_PARAMS default_params = {
	MGSL_MODE_HDLC,			/* unsigned long mode */
	0,				/* unsigned char loopback; */
	HDLC_FLAG_UNDERRUN_ABORT15,	/* unsigned short flags; */
	HDLC_ENCODING_NRZI_SPACE,	/* unsigned char encoding; */
	0,				/* unsigned long clock_speed; */
	0xff,				/* unsigned char addr_filter; */
	HDLC_CRC_16_CCITT,		/* unsigned short crc_type; */
	HDLC_PREAMBLE_LENGTH_8BITS,	/* unsigned char preamble_length; */
	HDLC_PREAMBLE_PATTERN_NONE,	/* unsigned char preamble; */
	9600,				/* unsigned long data_rate; */
	8,				/* unsigned char data_bits; */
	1,				/* unsigned char stop_bits; */
	ASYNC_PARITY_NONE		/* unsigned char parity; */
};

#define SHARED_MEM_ADDRESS_SIZE 0x40000
#define BUFFERLISTSIZE 4096
#define DMABUFFERSIZE 4096
#define MAXRXFRAMES 7

typedef struct _DMABUFFERENTRY
{
	u32 phys_addr;	/* 32-bit flat physical address of data buffer */
	volatile u16 count;	/* buffer size/data count */
	volatile u16 status;	/* Control/status field */
	volatile u16 rcc;	/* character count field */
	u16 reserved;	/* padding required by 16C32 */
	u32 link;	/* 32-bit flat link to next buffer entry */
	char *virt_addr;	/* virtual address of data buffer */
	u32 phys_entry;	/* physical address of this buffer entry */
	dma_addr_t dma_addr;
} DMABUFFERENTRY, *DMAPBUFFERENTRY;

/* The queue of BH actions to be performed */

#define BH_RECEIVE  1
#define BH_TRANSMIT 2
#define BH_STATUS   4

#define IO_PIN_SHUTDOWN_LIMIT 100

struct	_input_signal_events {
	int	ri_up;	
	int	ri_down;
	int	dsr_up;
	int	dsr_down;
	int	dcd_up;
	int	dcd_down;
	int	cts_up;
	int	cts_down;
};

/* transmit holding buffer definitions*/
#define MAX_TX_HOLDING_BUFFERS 5
struct tx_holding_buffer {
	int	buffer_size;
	unsigned char *	buffer;
};


/*
 * Device instance data structure
 */
 
struct mgsl_struct {
	int			magic;
	struct tty_port		port;
	int			line;
	int                     hw_version;
	
	struct mgsl_icount	icount;
	
	int			timeout;
	int			x_char;		/* xon/xoff character */
	u16			read_status_mask;
	u16			ignore_status_mask;	
	unsigned char 		*xmit_buf;
	int			xmit_head;
	int			xmit_tail;
	int			xmit_cnt;
	
	wait_queue_head_t	status_event_wait_q;
	wait_queue_head_t	event_wait_q;
	struct timer_list	tx_timer;	/* HDLC transmit timeout timer */
	struct mgsl_struct	*next_device;	/* device list link */
	
	spinlock_t irq_spinlock;		/* spinlock for synchronizing with ISR */
	struct work_struct task;		/* task structure for scheduling bh */

	u32 EventMask;			/* event trigger mask */
	u32 RecordedEvents;		/* pending events */

	u32 max_frame_size;		/* as set by device config */

	u32 pending_bh;

	bool bh_running;		/* Protection from multiple */
	int isr_overflow;
	bool bh_requested;
	
	int dcd_chkcount;		/* check counts to prevent */
	int cts_chkcount;		/* too many IRQs if a signal */
	int dsr_chkcount;		/* is floating */
	int ri_chkcount;

	char *buffer_list;		/* virtual address of Rx & Tx buffer lists */
	u32 buffer_list_phys;
	dma_addr_t buffer_list_dma_addr;

	unsigned int rx_buffer_count;	/* count of total allocated Rx buffers */
	DMABUFFERENTRY *rx_buffer_list;	/* list of receive buffer entries */
	unsigned int current_rx_buffer;

	int num_tx_dma_buffers;		/* number of tx dma frames required */
 	int tx_dma_buffers_used;
	unsigned int tx_buffer_count;	/* count of total allocated Tx buffers */
	DMABUFFERENTRY *tx_buffer_list;	/* list of transmit buffer entries */
	int start_tx_dma_buffer;	/* tx dma buffer to start tx dma operation */
	int current_tx_buffer;          /* next tx dma buffer to be loaded */
	
	unsigned char *intermediate_rxbuffer;

	int num_tx_holding_buffers;	/* number of tx holding buffer allocated */
	int get_tx_holding_index;  	/* next tx holding buffer for adapter to load */
	int put_tx_holding_index;  	/* next tx holding buffer to store user request */
	int tx_holding_count;		/* number of tx holding buffers waiting */
	struct tx_holding_buffer tx_holding_buffers[MAX_TX_HOLDING_BUFFERS];

	bool rx_enabled;
	bool rx_overflow;
	bool rx_rcc_underrun;

	bool tx_enabled;
	bool tx_active;
	u32 idle_mode;

	u16 cmr_value;
	u16 tcsr_value;

	char device_name[25];		/* device instance name */

	unsigned int bus_type;	/* expansion bus type (ISA,EISA,PCI) */
	unsigned char bus;		/* expansion bus number (zero based) */
	unsigned char function;		/* PCI device number */

	unsigned int io_base;		/* base I/O address of adapter */
	unsigned int io_addr_size;	/* size of the I/O address range */
	bool io_addr_requested;		/* true if I/O address requested */
	
	unsigned int irq_level;		/* interrupt level */
	unsigned long irq_flags;
	bool irq_requested;		/* true if IRQ requested */
	
	unsigned int dma_level;		/* DMA channel */
	bool dma_requested;		/* true if dma channel requested */

	u16 mbre_bit;
	u16 loopback_bits;
	u16 usc_idle_mode;

	MGSL_PARAMS params;		/* communications parameters */

	unsigned char serial_signals;	/* current serial signal states */

	bool irq_occurred;		/* for diagnostics use */
	unsigned int init_error;	/* Initialization startup error 		(DIAGS)	*/
	int	fDiagnosticsmode;	/* Driver in Diagnostic mode?			(DIAGS)	*/

	u32 last_mem_alloc;
	unsigned char* memory_base;	/* shared memory address (PCI only) */
	u32 phys_memory_base;
	bool shared_mem_requested;

	unsigned char* lcr_base;	/* local config registers (PCI only) */
	u32 phys_lcr_base;
	u32 lcr_offset;
	bool lcr_mem_requested;

	u32 misc_ctrl_value;
	char flag_buf[MAX_ASYNC_BUFFER_SIZE];
	char char_buf[MAX_ASYNC_BUFFER_SIZE];	
	bool drop_rts_on_tx_done;

	bool loopmode_insert_requested;
	bool loopmode_send_done_requested;
	
	struct	_input_signal_events	input_signal_events;

	/* generic HDLC device parts */
	int netcount;
	spinlock_t netlock;

#if SYNCLINK_GENERIC_HDLC
	struct net_device *netdev;
#endif
};

#define MGSL_MAGIC 0x5401

/*
 * The size of the serial xmit buffer is 1 page, or 4096 bytes
 */
#ifndef SERIAL_XMIT_SIZE
#define SERIAL_XMIT_SIZE 4096
#endif

/*
 * These macros define the offsets used in calculating the
 * I/O address of the specified USC registers.
 */


#define DCPIN 2		/* Bit 1 of I/O address */
#define SDPIN 4		/* Bit 2 of I/O address */

#define DCAR 0		/* DMA command/address register */
#define CCAR SDPIN		/* channel command/address register */
#define DATAREG DCPIN + SDPIN	/* serial data register */
#define MSBONLY 0x41
#define LSBONLY 0x40

/*
 * These macros define the register address (ordinal number)
 * used for writing address/value pairs to the USC.
 */

#define CMR	0x02	/* Channel mode Register */
#define CCSR	0x04	/* Channel Command/status Register */
#define CCR	0x06	/* Channel Control Register */
#define PSR	0x08	/* Port status Register */
#define PCR	0x0a	/* Port Control Register */
#define TMDR	0x0c	/* Test mode Data Register */
#define TMCR	0x0e	/* Test mode Control Register */
#define CMCR	0x10	/* Clock mode Control Register */
#define HCR	0x12	/* Hardware Configuration Register */
#define IVR	0x14	/* Interrupt Vector Register */
#define IOCR	0x16	/* Input/Output Control Register */
#define ICR	0x18	/* Interrupt Control Register */
#define DCCR	0x1a	/* Daisy Chain Control Register */
#define MISR	0x1c	/* Misc Interrupt status Register */
#define SICR	0x1e	/* status Interrupt Control Register */
#define RDR	0x20	/* Receive Data Register */
#define RMR	0x22	/* Receive mode Register */
#define RCSR	0x24	/* Receive Command/status Register */
#define RICR	0x26	/* Receive Interrupt Control Register */
#define RSR	0x28	/* Receive Sync Register */
#define RCLR	0x2a	/* Receive count Limit Register */
#define RCCR	0x2c	/* Receive Character count Register */
#define TC0R	0x2e	/* Time Constant 0 Register */
#define TDR	0x30	/* Transmit Data Register */
#define TMR	0x32	/* Transmit mode Register */
#define TCSR	0x34	/* Transmit Command/status Register */
#define TICR	0x36	/* Transmit Interrupt Control Register */
#define TSR	0x38	/* Transmit Sync Register */
#define TCLR	0x3a	/* Transmit count Limit Register */
#define TCCR	0x3c	/* Transmit Character count Register */
#define TC1R	0x3e	/* Time Constant 1 Register */


/*
 * MACRO DEFINITIONS FOR DMA REGISTERS
 */

#define DCR	0x06	/* DMA Control Register (shared) */
#define DACR	0x08	/* DMA Array count Register (shared) */
#define BDCR	0x12	/* Burst/Dwell Control Register (shared) */
#define DIVR	0x14	/* DMA Interrupt Vector Register (shared) */	
#define DICR	0x18	/* DMA Interrupt Control Register (shared) */
#define CDIR	0x1a	/* Clear DMA Interrupt Register (shared) */
#define SDIR	0x1c	/* Set DMA Interrupt Register (shared) */

#define TDMR	0x02	/* Transmit DMA mode Register */
#define TDIAR	0x1e	/* Transmit DMA Interrupt Arm Register */
#define TBCR	0x2a	/* Transmit Byte count Register */
#define TARL	0x2c	/* Transmit Address Register (low) */
#define TARU	0x2e	/* Transmit Address Register (high) */
#define NTBCR	0x3a	/* Next Transmit Byte count Register */
#define NTARL	0x3c	/* Next Transmit Address Register (low) */
#define NTARU	0x3e	/* Next Transmit Address Register (high) */

#define RDMR	0x82	/* Receive DMA mode Register (non-shared) */
#define RDIAR	0x9e	/* Receive DMA Interrupt Arm Register */
#define RBCR	0xaa	/* Receive Byte count Register */
#define RARL	0xac	/* Receive Address Register (low) */
#define RARU	0xae	/* Receive Address Register (high) */
#define NRBCR	0xba	/* Next Receive Byte count Register */
#define NRARL	0xbc	/* Next Receive Address Register (low) */
#define NRARU	0xbe	/* Next Receive Address Register (high) */


/*
 * MACRO DEFINITIONS FOR MODEM STATUS BITS
 */

#define MODEMSTATUS_DTR 0x80
#define MODEMSTATUS_DSR 0x40
#define MODEMSTATUS_RTS 0x20
#define MODEMSTATUS_CTS 0x10
#define MODEMSTATUS_RI  0x04
#define MODEMSTATUS_DCD 0x01


/*
 * Channel Command/Address Register (CCAR) Command Codes
 */

#define RTCmd_Null			0x0000
#define RTCmd_ResetHighestIus		0x1000
#define RTCmd_TriggerChannelLoadDma	0x2000
#define RTCmd_TriggerRxDma		0x2800
#define RTCmd_TriggerTxDma		0x3000
#define RTCmd_TriggerRxAndTxDma		0x3800
#define RTCmd_PurgeRxFifo		0x4800
#define RTCmd_PurgeTxFifo		0x5000
#define RTCmd_PurgeRxAndTxFifo		0x5800
#define RTCmd_LoadRcc			0x6800
#define RTCmd_LoadTcc			0x7000
#define RTCmd_LoadRccAndTcc		0x7800
#define RTCmd_LoadTC0			0x8800
#define RTCmd_LoadTC1			0x9000
#define RTCmd_LoadTC0AndTC1		0x9800
#define RTCmd_SerialDataLSBFirst	0xa000
#define RTCmd_SerialDataMSBFirst	0xa800
#define RTCmd_SelectBigEndian		0xb000
#define RTCmd_SelectLittleEndian	0xb800


/*
 * DMA Command/Address Register (DCAR) Command Codes
 */

#define DmaCmd_Null			0x0000
#define DmaCmd_ResetTxChannel		0x1000
#define DmaCmd_ResetRxChannel		0x1200
#define DmaCmd_StartTxChannel		0x2000
#define DmaCmd_StartRxChannel		0x2200
#define DmaCmd_ContinueTxChannel	0x3000
#define DmaCmd_ContinueRxChannel	0x3200
#define DmaCmd_PauseTxChannel		0x4000
#define DmaCmd_PauseRxChannel		0x4200
#define DmaCmd_AbortTxChannel		0x5000
#define DmaCmd_AbortRxChannel		0x5200
#define DmaCmd_InitTxChannel		0x7000
#define DmaCmd_InitRxChannel		0x7200
#define DmaCmd_ResetHighestDmaIus	0x8000
#define DmaCmd_ResetAllChannels		0x9000
#define DmaCmd_StartAllChannels		0xa000
#define DmaCmd_ContinueAllChannels	0xb000
#define DmaCmd_PauseAllChannels		0xc000
#define DmaCmd_AbortAllChannels		0xd000
#define DmaCmd_InitAllChannels		0xf000

#define TCmd_Null			0x0000
#define TCmd_ClearTxCRC			0x2000
#define TCmd_SelectTicrTtsaData		0x4000
#define TCmd_SelectTicrTxFifostatus	0x5000
#define TCmd_SelectTicrIntLevel		0x6000
#define TCmd_SelectTicrdma_level		0x7000
#define TCmd_SendFrame			0x8000
#define TCmd_SendAbort			0x9000
#define TCmd_EnableDleInsertion		0xc000
#define TCmd_DisableDleInsertion	0xd000
#define TCmd_ClearEofEom		0xe000
#define TCmd_SetEofEom			0xf000

#define RCmd_Null			0x0000
#define RCmd_ClearRxCRC			0x2000
#define RCmd_EnterHuntmode		0x3000
#define RCmd_SelectRicrRtsaData		0x4000
#define RCmd_SelectRicrRxFifostatus	0x5000
#define RCmd_SelectRicrIntLevel		0x6000
#define RCmd_SelectRicrdma_level		0x7000

/*
 * Bits for enabling and disabling IRQs in Interrupt Control Register (ICR)
 */
 
#define RECEIVE_STATUS		BIT5
#define RECEIVE_DATA		BIT4
#define TRANSMIT_STATUS		BIT3
#define TRANSMIT_DATA		BIT2
#define IO_PIN			BIT1
#define MISC			BIT0


/*
 * Receive status Bits in Receive Command/status Register RCSR
 */

#define RXSTATUS_SHORT_FRAME		BIT8
#define RXSTATUS_CODE_VIOLATION		BIT8
#define RXSTATUS_EXITED_HUNT		BIT7
#define RXSTATUS_IDLE_RECEIVED		BIT6
#define RXSTATUS_BREAK_RECEIVED		BIT5
#define RXSTATUS_ABORT_RECEIVED		BIT5
#define RXSTATUS_RXBOUND		BIT4
#define RXSTATUS_CRC_ERROR		BIT3
#define RXSTATUS_FRAMING_ERROR		BIT3
#define RXSTATUS_ABORT			BIT2
#define RXSTATUS_PARITY_ERROR		BIT2
#define RXSTATUS_OVERRUN		BIT1
#define RXSTATUS_DATA_AVAILABLE		BIT0
#define RXSTATUS_ALL			0x01f6
#define usc_UnlatchRxstatusBits(a,b) usc_OutReg( (a), RCSR, (u16)((b) & RXSTATUS_ALL) )

/*
 * Values for setting transmit idle mode in 
 * Transmit Control/status Register (TCSR)
 */
#define IDLEMODE_FLAGS			0x0000
#define IDLEMODE_ALT_ONE_ZERO		0x0100
#define IDLEMODE_ZERO			0x0200
#define IDLEMODE_ONE			0x0300
#define IDLEMODE_ALT_MARK_SPACE		0x0500
#define IDLEMODE_SPACE			0x0600
#define IDLEMODE_MARK			0x0700
#define IDLEMODE_MASK			0x0700

/*
 * IUSC revision identifiers
 */
#define	IUSC_SL1660			0x4d44
#define IUSC_PRE_SL1660			0x4553

/*
 * Transmit status Bits in Transmit Command/status Register (TCSR)
 */

#define TCSR_PRESERVE			0x0F00

#define TCSR_UNDERWAIT			BIT11
#define TXSTATUS_PREAMBLE_SENT		BIT7
#define TXSTATUS_IDLE_SENT		BIT6
#define TXSTATUS_ABORT_SENT		BIT5
#define TXSTATUS_EOF_SENT		BIT4
#define TXSTATUS_EOM_SENT		BIT4
#define TXSTATUS_CRC_SENT		BIT3
#define TXSTATUS_ALL_SENT		BIT2
#define TXSTATUS_UNDERRUN		BIT1
#define TXSTATUS_FIFO_EMPTY		BIT0
#define TXSTATUS_ALL			0x00fa
#define usc_UnlatchTxstatusBits(a,b) usc_OutReg( (a), TCSR, (u16)((a)->tcsr_value + ((b) & 0x00FF)) )
				

#define MISCSTATUS_RXC_LATCHED		BIT15
#define MISCSTATUS_RXC			BIT14
#define MISCSTATUS_TXC_LATCHED		BIT13
#define MISCSTATUS_TXC			BIT12
#define MISCSTATUS_RI_LATCHED		BIT11
#define MISCSTATUS_RI			BIT10
#define MISCSTATUS_DSR_LATCHED		BIT9
#define MISCSTATUS_DSR			BIT8
#define MISCSTATUS_DCD_LATCHED		BIT7
#define MISCSTATUS_DCD			BIT6
#define MISCSTATUS_CTS_LATCHED		BIT5
#define MISCSTATUS_CTS			BIT4
#define MISCSTATUS_RCC_UNDERRUN		BIT3
#define MISCSTATUS_DPLL_NO_SYNC		BIT2
#define MISCSTATUS_BRG1_ZERO		BIT1
#define MISCSTATUS_BRG0_ZERO		BIT0

#define usc_UnlatchIostatusBits(a,b) usc_OutReg((a),MISR,(u16)((b) & 0xaaa0))
#define usc_UnlatchMiscstatusBits(a,b) usc_OutReg((a),MISR,(u16)((b) & 0x000f))

#define SICR_RXC_ACTIVE			BIT15
#define SICR_RXC_INACTIVE		BIT14
#define SICR_RXC			(BIT15+BIT14)
#define SICR_TXC_ACTIVE			BIT13
#define SICR_TXC_INACTIVE		BIT12
#define SICR_TXC			(BIT13+BIT12)
#define SICR_RI_ACTIVE			BIT11
#define SICR_RI_INACTIVE		BIT10
#define SICR_RI				(BIT11+BIT10)
#define SICR_DSR_ACTIVE			BIT9
#define SICR_DSR_INACTIVE		BIT8
#define SICR_DSR			(BIT9+BIT8)
#define SICR_DCD_ACTIVE			BIT7
#define SICR_DCD_INACTIVE		BIT6
#define SICR_DCD			(BIT7+BIT6)
#define SICR_CTS_ACTIVE			BIT5
#define SICR_CTS_INACTIVE		BIT4
#define SICR_CTS			(BIT5+BIT4)
#define SICR_RCC_UNDERFLOW		BIT3
#define SICR_DPLL_NO_SYNC		BIT2
#define SICR_BRG1_ZERO			BIT1
#define SICR_BRG0_ZERO			BIT0

void usc_DisableMasterIrqBit( struct mgsl_struct *info );
void usc_EnableMasterIrqBit( struct mgsl_struct *info );
void usc_EnableInterrupts( struct mgsl_struct *info, u16 IrqMask );
void usc_DisableInterrupts( struct mgsl_struct *info, u16 IrqMask );
void usc_ClearIrqPendingBits( struct mgsl_struct *info, u16 IrqMask );

#define usc_EnableInterrupts( a, b ) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0xff00) + 0xc0 + (b)) )

#define usc_DisableInterrupts( a, b ) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0xff00) + 0x80 + (b)) )

#define usc_EnableMasterIrqBit(a) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0x0f00) + 0xb000) )

#define usc_DisableMasterIrqBit(a) \
	usc_OutReg( (a), ICR, (u16)(usc_InReg((a),ICR) & 0x7f00) )

#define usc_ClearIrqPendingBits( a, b ) usc_OutReg( (a), DCCR, 0x40 + (b) )

/*
 * Transmit status Bits in Transmit Control status Register (TCSR)
 * and Transmit Interrupt Control Register (TICR) (except BIT2, BIT0)
 */

#define TXSTATUS_PREAMBLE_SENT	BIT7
#define TXSTATUS_IDLE_SENT	BIT6
#define TXSTATUS_ABORT_SENT	BIT5
#define TXSTATUS_EOF		BIT4
#define TXSTATUS_CRC_SENT	BIT3
#define TXSTATUS_ALL_SENT	BIT2
#define TXSTATUS_UNDERRUN	BIT1
#define TXSTATUS_FIFO_EMPTY	BIT0

#define DICR_MASTER		BIT15
#define DICR_TRANSMIT		BIT0
#define DICR_RECEIVE		BIT1

#define usc_EnableDmaInterrupts(a,b) \
	usc_OutDmaReg( (a), DICR, (u16)(usc_InDmaReg((a),DICR) | (b)) )

#define usc_DisableDmaInterrupts(a,b) \
	usc_OutDmaReg( (a), DICR, (u16)(usc_InDmaReg((a),DICR) & ~(b)) )

#define usc_EnableStatusIrqs(a,b) \
	usc_OutReg( (a), SICR, (u16)(usc_InReg((a),SICR) | (b)) )

#define usc_DisablestatusIrqs(a,b) \
	usc_OutReg( (a), SICR, (u16)(usc_InReg((a),SICR) & ~(b)) )

/* Transmit status Bits in Transmit Control status Register (TCSR) */
/* and Transmit Interrupt Control Register (TICR) (except BIT2, BIT0) */


#define DISABLE_UNCONDITIONAL    0
#define DISABLE_END_OF_FRAME     1
#define ENABLE_UNCONDITIONAL     2
#define ENABLE_AUTO_CTS          3
#define ENABLE_AUTO_DCD          3
#define usc_EnableTransmitter(a,b) \
	usc_OutReg( (a), TMR, (u16)((usc_InReg((a),TMR) & 0xfffc) | (b)) )
#define usc_EnableReceiver(a,b) \
	usc_OutReg( (a), RMR, (u16)((usc_InReg((a),RMR) & 0xfffc) | (b)) )

static u16  usc_InDmaReg( struct mgsl_struct *info, u16 Port );
static void usc_OutDmaReg( struct mgsl_struct *info, u16 Port, u16 Value );
static void usc_DmaCmd( struct mgsl_struct *info, u16 Cmd );

static u16  usc_InReg( struct mgsl_struct *info, u16 Port );
static void usc_OutReg( struct mgsl_struct *info, u16 Port, u16 Value );
static void usc_RTCmd( struct mgsl_struct *info, u16 Cmd );
void usc_RCmd( struct mgsl_struct *info, u16 Cmd );
void usc_TCmd( struct mgsl_struct *info, u16 Cmd );

#define usc_TCmd(a,b) usc_OutReg((a), TCSR, (u16)((a)->tcsr_value + (b)))
#define usc_RCmd(a,b) usc_OutReg((a), RCSR, (b))

#define usc_SetTransmitSyncChars(a,s0,s1) usc_OutReg((a), TSR, (u16)(((u16)s0<<8)|(u16)s1))

static void usc_process_rxoverrun_sync( struct mgsl_struct *info );
static void usc_start_receiver( struct mgsl_struct *info );
static void usc_stop_receiver( struct mgsl_struct *info );

static void usc_start_transmitter( struct mgsl_struct *info );
static void usc_stop_transmitter( struct mgsl_struct *info );
static void usc_set_txidle( struct mgsl_struct *info );
static void usc_load_txfifo( struct mgsl_struct *info );

static void usc_enable_aux_clock( struct mgsl_struct *info, u32 DataRate );
static void usc_enable_loopback( struct mgsl_struct *info, int enable );

static void usc_get_serial_signals( struct mgsl_struct *info );
static void usc_set_serial_signals( struct mgsl_struct *info );

static void usc_reset( struct mgsl_struct *info );

static void usc_set_sync_mode( struct mgsl_struct *info );
static void usc_set_sdlc_mode( struct mgsl_struct *info );
static void usc_set_async_mode( struct mgsl_struct *info );
static void usc_enable_async_clock( struct mgsl_struct *info, u32 DataRate );

static void usc_loopback_frame( struct mgsl_struct *info );

static void mgsl_tx_timeout(unsigned long context);


static void usc_loopmode_cancel_transmit( struct mgsl_struct * info );
static void usc_loopmode_insert_request( struct mgsl_struct * info );
static int usc_loopmode_active( struct mgsl_struct * info);
static void usc_loopmode_send_done( struct mgsl_struct * info );

static int mgsl_ioctl_common(struct mgsl_struct *info, unsigned int cmd, unsigned long arg);

#if SYNCLINK_GENERIC_HDLC
#define dev_to_port(D) (dev_to_hdlc(D)->priv)
static void hdlcdev_tx_done(struct mgsl_struct *info);
static void hdlcdev_rx(struct mgsl_struct *info, char *buf, int size);
static int  hdlcdev_init(struct mgsl_struct *info);
static void hdlcdev_exit(struct mgsl_struct *info);
#endif

/*
 * Defines a BUS descriptor value for the PCI adapter
 * local bus address ranges.
 */

#define BUS_DESCRIPTOR( WrHold, WrDly, RdDly, Nwdd, Nwad, Nxda, Nrdd, Nrad ) \
(0x00400020 + \
((WrHold) << 30) + \
((WrDly)  << 28) + \
((RdDly)  << 26) + \
((Nwdd)   << 20) + \
((Nwad)   << 15) + \
((Nxda)   << 13) + \
((Nrdd)   << 11) + \
((Nrad)   <<  6) )

static void mgsl_trace_block(struct mgsl_struct *info,const char* data, int count, int xmit);

/*
 * Adapter diagnostic routines
 */
static bool mgsl_register_test( struct mgsl_struct *info );
static bool mgsl_irq_test( struct mgsl_struct *info );
static bool mgsl_dma_test( struct mgsl_struct *info );
static bool mgsl_memory_test( struct mgsl_struct *info );
static int mgsl_adapter_test( struct mgsl_struct *info );

/*
 * device and resource management routines
 */
static int mgsl_claim_resources(struct mgsl_struct *info);
static void mgsl_release_resources(struct mgsl_struct *info);
static void mgsl_add_device(struct mgsl_struct *info);
static struct mgsl_struct* mgsl_allocate_device(void);

/*
 * DMA buffer manupulation functions.
 */
static void mgsl_free_rx_frame_buffers( struct mgsl_struct *info, unsigned int StartIndex, unsigned int EndIndex );
static bool mgsl_get_rx_frame( struct mgsl_struct *info );
static bool mgsl_get_raw_rx_frame( struct mgsl_struct *info );
static void mgsl_reset_rx_dma_buffers( struct mgsl_struct *info );
static void mgsl_reset_tx_dma_buffers( struct mgsl_struct *info );
static int num_free_tx_dma_buffers(struct mgsl_struct *info);
static void mgsl_load_tx_dma_buffer( struct mgsl_struct *info, const char *Buffer, unsigned int BufferSize);
static void mgsl_load_pci_memory(char* TargetPtr, const char* SourcePtr, unsigned short count);

/*
 * DMA and Shared Memory buffer allocation and formatting
 */
static int  mgsl_allocate_dma_buffers(struct mgsl_struct *info);
static void mgsl_free_dma_buffers(struct mgsl_struct *info);
static int  mgsl_alloc_frame_memory(struct mgsl_struct *info, DMABUFFERENTRY *BufferList,int Buffercount);
static void mgsl_free_frame_memory(struct mgsl_struct *info, DMABUFFERENTRY *BufferList,int Buffercount);
static int  mgsl_alloc_buffer_list_memory(struct mgsl_struct *info);
static void mgsl_free_buffer_list_memory(struct mgsl_struct *info);
static int mgsl_alloc_intermediate_rxbuffer_memory(struct mgsl_struct *info);
static void mgsl_free_intermediate_rxbuffer_memory(struct mgsl_struct *info);
static int mgsl_alloc_intermediate_txbuffer_memory(struct mgsl_struct *info);
static void mgsl_free_intermediate_txbuffer_memory(struct mgsl_struct *info);
static bool load_next_tx_holding_buffer(struct mgsl_struct *info);
static int save_tx_buffer_request(struct mgsl_struct *info,const char *Buffer, unsigned int BufferSize);

/*
 * Bottom half interrupt handlers
 */
static void mgsl_bh_handler(struct work_struct *work);
static void mgsl_bh_receive(struct mgsl_struct *info);
static void mgsl_bh_transmit(struct mgsl_struct *info);
static void mgsl_bh_status(struct mgsl_struct *info);

/*
 * Interrupt handler routines and dispatch table.
 */
static void mgsl_isr_null( struct mgsl_struct *info );
static void mgsl_isr_transmit_data( struct mgsl_struct *info );
static void mgsl_isr_receive_data( struct mgsl_struct *info );
static void mgsl_isr_receive_status( struct mgsl_struct *info );
static void mgsl_isr_transmit_status( struct mgsl_struct *info );
static void mgsl_isr_io_pin( struct mgsl_struct *info );
static void mgsl_isr_misc( struct mgsl_struct *info );
static void mgsl_isr_receive_dma( struct mgsl_struct *info );
static void mgsl_isr_transmit_dma( struct mgsl_struct *info );

typedef void (*isr_dispatch_func)(struct mgsl_struct *);

static isr_dispatch_func UscIsrTable[7] =
{
	mgsl_isr_null,
	mgsl_isr_misc,
	mgsl_isr_io_pin,
	mgsl_isr_transmit_data,
	mgsl_isr_transmit_status,
	mgsl_isr_receive_data,
	mgsl_isr_receive_status
};

/*
 * ioctl call handlers
 */
static int tiocmget(struct tty_struct *tty, struct file *file);
static int tiocmset(struct tty_struct *tty, struct file *file,
		    unsigned int set, unsigned int clear);
static int mgsl_get_stats(struct mgsl_struct * info, struct mgsl_icount
	__user *user_icount);
static int mgsl_get_params(struct mgsl_struct * info, MGSL_PARAMS  __user *user_params);
static int mgsl_set_params(struct mgsl_struct * info, MGSL_PARAMS  __user *new_params);
static int mgsl_get_txidle(struct mgsl_struct * info, int __user *idle_mode);
static int mgsl_set_txidle(struct mgsl_struct * info, int idle_mode);
static int mgsl_txenable(struct mgsl_struct * info, int enable);
static int mgsl_txabort(struct mgsl_struct * info);
static int mgsl_rxenable(struct mgsl_struct * info, int enable);
static int mgsl_wait_event(struct mgsl_struct * info, int __user *mask);
static int mgsl_loopmode_send_done( struct mgsl_struct * info );

/* set non-zero on successful registration with PCI subsystem */
static bool pci_registered;

/*
 * Global linked list of SyncLink devices
 */
static struct mgsl_struct *mgsl_device_list;
static int mgsl_device_count;

/*
 * Set this param to non-zero to load eax with the
 * .text section address and breakpoint on module load.
 * This is useful for use with gdb and add-symbol-file command.
 */
static int break_on_load;

/*
 * Driver major number, defaults to zero to get auto
 * assigned major number. May be forced as module parameter.
 */
static int ttymajor;

/*
 * Array of user specified options for ISA adapters.
 */
static int io[MAX_ISA_DEVICES];
static int irq[MAX_ISA_DEVICES];
static int dma[MAX_ISA_DEVICES];
static int debug_level;
static int maxframe[MAX_TOTAL_DEVICES];
static int txdmabufs[MAX_TOTAL_DEVICES];
static int txholdbufs[MAX_TOTAL_DEVICES];
	
module_param(break_on_load, bool, 0);
module_param(ttymajor, int, 0);
module_param_array(io, int, NULL, 0);
module_param_array(irq, int, NULL, 0);
module_param_array(dma, int, NULL, 0);
module_param(debug_level, int, 0);
module_param_array(maxframe, int, NULL, 0);
module_param_array(txdmabufs, int, NULL, 0);
module_param_array(txholdbufs, int, NULL, 0);

static char *driver_name = "SyncLink serial driver";
static char *driver_version = "$Revision: 4.38 $";

static int synclink_init_one (struct pci_dev *dev,
				     const struct pci_device_id *ent);
static void synclink_remove_one (struct pci_dev *dev);

static struct pci_device_id synclink_pci_tbl[] = {
	{ PCI_VENDOR_ID_MICROGATE, PCI_DEVICE_ID_MICROGATE_USC, PCI_ANY_ID, PCI_ANY_ID, },
	{ PCI_VENDOR_ID_MICROGATE, 0x0210, PCI_ANY_ID, PCI_ANY_ID, },
	{ 0, }, /* terminate list */
};
MODULE_DEVICE_TABLE(pci, synclink_pci_tbl);

MODULE_LICENSE("GPL");

static struct pci_driver synclink_pci_driver = {
	.name		= "synclink",
	.id_table	= synclink_pci_tbl,
	.probe		= synclink_init_one,
	.remove		= __devexit_p(synclink_remove_one),
};

static struct tty_driver *serial_driver;

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256


static void mgsl_change_params(struct mgsl_struct *info);
static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout);

/*
 * 1st function defined in .text section. Calling this function in
 * init_module() followed by a breakpoint allows a remote debugger
 * (gdb) to get the .text address for the add-symbol-file command.
 * This allows remote debugging of dynamically loadable modules.
 */
static void* mgsl_get_text_ptr(void)
{
	return mgsl_get_text_ptr;
}

static inline int mgsl_paranoia_check(struct mgsl_struct *info,
					char *name, const char *routine)
{
#ifdef MGSL_PARANOIA_CHECK
	static const char *badmagic =
		"Warning: bad magic number for mgsl struct (%s) in %s\n";
	static const char *badinfo =
		"Warning: null mgsl_struct for (%s) in %s\n";

	if (!info) {
		printk(badinfo, name, routine);
		return 1;
	}
	if (info->magic != MGSL_MAGIC) {
		printk(badmagic, name, routine);
		return 1;
	}
#else
	if (!info)
		return 1;
#endif
	return 0;
}

/**
 * line discipline callback wrappers
 *
 * The wrappers maintain line discipline references
 * while calling into the line discipline.
 *
 * ldisc_receive_buf  - pass receive data to line discipline
 */

static void ldisc_receive_buf(struct tty_struct *tty,
			      const __u8 *data, char *flags, int count)
{
	struct tty_ldisc *ld;
	if (!tty)
		return;
	ld = tty_ldisc_ref(tty);
	if (ld) {
		if (ld->ops->receive_buf)
			ld->ops->receive_buf(tty, data, flags, count);
		tty_ldisc_deref(ld);
	}
}

/* mgsl_stop()		throttle (stop) transmitter
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_stop(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_stop"))
		return;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("mgsl_stop(%s)\n",info->device_name);	
		
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (info->tx_enabled)
	 	usc_stop_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_stop() */

/* mgsl_start()		release (start) transmitter
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_start(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_start"))
		return;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("mgsl_start(%s)\n",info->device_name);	
		
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (!info->tx_enabled)
	 	usc_start_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_start() */

/*
 * Bottom half work queue access functions
 */

/* mgsl_bh_action()	Return next bottom half action to perform.
 * Return Value:	BH action code or 0 if nothing to do.
 */
static int mgsl_bh_action(struct mgsl_struct *info)
{
	unsigned long flags;
	int rc = 0;
	
	spin_lock_irqsave(&info->irq_spinlock,flags);

	if (info->pending_bh & BH_RECEIVE) {
		info->pending_bh &= ~BH_RECEIVE;
		rc = BH_RECEIVE;
	} else if (info->pending_bh & BH_TRANSMIT) {
		info->pending_bh &= ~BH_TRANSMIT;
		rc = BH_TRANSMIT;
	} else if (info->pending_bh & BH_STATUS) {
		info->pending_bh &= ~BH_STATUS;
		rc = BH_STATUS;
	}

	if (!rc) {
		/* Mark BH routine as complete */
		info->bh_running = false;
		info->bh_requested = false;
	}
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
	return rc;
}

/*
 * 	Perform bottom half processing of work items queued by ISR.
 */
static void mgsl_bh_handler(struct work_struct *work)
{
	struct mgsl_struct *info =
		container_of(work, struct mgsl_struct, task);
	int action;

	if (!info)
		return;
		
	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_handler(%s) entry\n",
			__FILE__,__LINE__,info->device_name);
	
	info->bh_running = true;

	while((action = mgsl_bh_action(info)) != 0) {
	
		/* Process work item */
		if ( debug_level >= DEBUG_LEVEL_BH )
			printk( "%s(%d):mgsl_bh_handler() work item action=%d\n",
				__FILE__,__LINE__,action);

		switch (action) {
		
		case BH_RECEIVE:
			mgsl_bh_receive(info);
			break;
		case BH_TRANSMIT:
			mgsl_bh_transmit(info);
			break;
		case BH_STATUS:
			mgsl_bh_status(info);
			break;
		default:
			/* unknown work item ID */
			printk("Unknown work item ID=%08X!\n", action);
			break;
		}
	}

	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_handler(%s) exit\n",
			__FILE__,__LINE__,info->device_name);
}

static void mgsl_bh_receive(struct mgsl_struct *info)
{
	bool (*get_rx_frame)(struct mgsl_struct *info) =
		(info->params.mode == MGSL_MODE_HDLC ? mgsl_get_rx_frame : mgsl_get_raw_rx_frame);

	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_receive(%s)\n",
			__FILE__,__LINE__,info->device_name);
	
	do
	{
		if (info->rx_rcc_underrun) {
			unsigned long flags;
			spin_lock_irqsave(&info->irq_spinlock,flags);
			usc_start_receiver(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			return;
		}
	} while(get_rx_frame(info));
}

static void mgsl_bh_transmit(struct mgsl_struct *info)
{
	struct tty_struct *tty = info->port.tty;
	unsigned long flags;
	
	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_transmit() entry on %s\n",
			__FILE__,__LINE__,info->device_name);

	if (tty)
		tty_wakeup(tty);

	/* if transmitter idle and loopmode_send_done_requested
	 * then start echoing RxD to TxD
	 */
	spin_lock_irqsave(&info->irq_spinlock,flags);
 	if ( !info->tx_active && info->loopmode_send_done_requested )
 		usc_loopmode_send_done( info );
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}

static void mgsl_bh_status(struct mgsl_struct *info)
{
	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_status() entry on %s\n",
			__FILE__,__LINE__,info->device_name);

	info->ri_chkcount = 0;
	info->dsr_chkcount = 0;
	info->dcd_chkcount = 0;
	info->cts_chkcount = 0;
}

/* mgsl_isr_receive_status()
 * 
 *	Service a receive status interrupt. The type of status
 *	interrupt is indicated by the state of the RCSR.
 *	This is only used for HDLC mode.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_status( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, RCSR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_receive_status status=%04X\n",
			__FILE__,__LINE__,status);
			
 	if ( (status & RXSTATUS_ABORT_RECEIVED) && 
		info->loopmode_insert_requested &&
 		usc_loopmode_active(info) )
 	{
		++info->icount.rxabort;
	 	info->loopmode_insert_requested = false;
 
 		/* clear CMR:13 to start echoing RxD to TxD */
		info->cmr_value &= ~BIT13;
 		usc_OutReg(info, CMR, info->cmr_value);
 
		/* disable received abort irq (no longer required) */
	 	usc_OutReg(info, RICR,
 			(usc_InReg(info, RICR) & ~RXSTATUS_ABORT_RECEIVED));
 	}

	if (status & (RXSTATUS_EXITED_HUNT + RXSTATUS_IDLE_RECEIVED)) {
		if (status & RXSTATUS_EXITED_HUNT)
			info->icount.exithunt++;
		if (status & RXSTATUS_IDLE_RECEIVED)
			info->icount.rxidle++;
		wake_up_interruptible(&info->event_wait_q);
	}

	if (status & RXSTATUS_OVERRUN){
		info->icount.rxover++;
		usc_process_rxoverrun_sync( info );
	}

	usc_ClearIrqPendingBits( info, RECEIVE_STATUS );
	usc_UnlatchRxstatusBits( info, status );

}	/* end of mgsl_isr_receive_status() */

/* mgsl_isr_transmit_status()
 * 
 * 	Service a transmit status interrupt
 *	HDLC mode :end of transmit frame
 *	Async mode:all data is sent
 * 	transmit status is indicated by bits in the TCSR.
 * 
 * Arguments:		info	       pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_status( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, TCSR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_transmit_status status=%04X\n",
			__FILE__,__LINE__,status);
	
	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS );
	usc_UnlatchTxstatusBits( info, status );
	
	if ( status & (TXSTATUS_UNDERRUN | TXSTATUS_ABORT_SENT) )
	{
		/* finished sending HDLC abort. This may leave	*/
		/* the TxFifo with data from the aborted frame	*/
		/* so purge the TxFifo. Also shutdown the DMA	*/
		/* channel in case there is data remaining in 	*/
		/* the DMA buffer				*/
 		usc_DmaCmd( info, DmaCmd_ResetTxChannel );
 		usc_RTCmd( info, RTCmd_PurgeTxFifo );
	}
 
	if ( status & TXSTATUS_EOF_SENT )
		info->icount.txok++;
	else if ( status & TXSTATUS_UNDERRUN )
		info->icount.txunder++;
	else if ( status & TXSTATUS_ABORT_SENT )
		info->icount.txabort++;
	else
		info->icount.txunder++;
			
	info->tx_active = false;
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	del_timer(&info->tx_timer);	
	
	if ( info->drop_rts_on_tx_done ) {
		usc_get_serial_signals( info );
		if ( info->serial_signals & SerialSignal_RTS ) {
			info->serial_signals &= ~SerialSignal_RTS;
			usc_set_serial_signals( info );
		}
		info->drop_rts_on_tx_done = false;
	}

#if SYNCLINK_GENERIC_HDLC
	if (info->netcount)
		hdlcdev_tx_done(info);
	else 
#endif
	{
		if (info->port.tty->stopped || info->port.tty->hw_stopped) {
			usc_stop_transmitter(info);
			return;
		}
		info->pending_bh |= BH_TRANSMIT;
	}

}	/* end of mgsl_isr_transmit_status() */

/* mgsl_isr_io_pin()
 * 
 * 	Service an Input/Output pin interrupt. The type of
 * 	interrupt is indicated by bits in the MISR
 * 	
 * Arguments:		info	       pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_io_pin( struct mgsl_struct *info )
{
 	struct	mgsl_icount *icount;
	u16 status = usc_InReg( info, MISR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_io_pin status=%04X\n",
			__FILE__,__LINE__,status);
			
	usc_ClearIrqPendingBits( info, IO_PIN );
	usc_UnlatchIostatusBits( info, status );

	if (status & (MISCSTATUS_CTS_LATCHED | MISCSTATUS_DCD_LATCHED |
	              MISCSTATUS_DSR_LATCHED | MISCSTATUS_RI_LATCHED) ) {
		icount = &info->icount;
		/* update input line counters */
		if (status & MISCSTATUS_RI_LATCHED) {
			if ((info->ri_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_RI);
			icount->rng++;
			if ( status & MISCSTATUS_RI )
				info->input_signal_events.ri_up++;	
			else
				info->input_signal_events.ri_down++;	
		}
		if (status & MISCSTATUS_DSR_LATCHED) {
			if ((info->dsr_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_DSR);
			icount->dsr++;
			if ( status & MISCSTATUS_DSR )
				info->input_signal_events.dsr_up++;
			else
				info->input_signal_events.dsr_down++;
		}
		if (status & MISCSTATUS_DCD_LATCHED) {
			if ((info->dcd_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_DCD);
			icount->dcd++;
			if (status & MISCSTATUS_DCD) {
				info->input_signal_events.dcd_up++;
			} else
				info->input_signal_events.dcd_down++;
#if SYNCLINK_GENERIC_HDLC
			if (info->netcount) {
				if (status & MISCSTATUS_DCD)
					netif_carrier_on(info->netdev);
				else
					netif_carrier_off(info->netdev);
			}
#endif
		}
		if (status & MISCSTATUS_CTS_LATCHED)
		{
			if ((info->cts_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_CTS);
			icount->cts++;
			if ( status & MISCSTATUS_CTS )
				info->input_signal_events.cts_up++;
			else
				info->input_signal_events.cts_down++;
		}
		wake_up_interruptible(&info->status_event_wait_q);
		wake_up_interruptible(&info->event_wait_q);

		if ( (info->port.flags & ASYNC_CHECK_CD) && 
		     (status & MISCSTATUS_DCD_LATCHED) ) {
			if ( debug_level >= DEBUG_LEVEL_ISR )
				printk("%s CD now %s...", info->device_name,
				       (status & MISCSTATUS_DCD) ? "on" : "off");
			if (status & MISCSTATUS_DCD)
				wake_up_interruptible(&info->port.open_wait);
			else {
				if ( debug_level >= DEBUG_LEVEL_ISR )
					printk("doing serial hangup...");
				if (info->port.tty)
					tty_hangup(info->port.tty);
			}
		}
	
		if ( (info->port.flags & ASYNC_CTS_FLOW) && 
		     (status & MISCSTATUS_CTS_LATCHED) ) {
			if (info->port.tty->hw_stopped) {
				if (status & MISCSTATUS_CTS) {
					if ( debug_level >= DEBUG_LEVEL_ISR )
						printk("CTS tx start...");
					if (info->port.tty)
						info->port.tty->hw_stopped = 0;
					usc_start_transmitter(info);
					info->pending_bh |= BH_TRANSMIT;
					return;
				}
			} else {
				if (!(status & MISCSTATUS_CTS)) {
					if ( debug_level >= DEBUG_LEVEL_ISR )
						printk("CTS tx stop...");
					if (info->port.tty)
						info->port.tty->hw_stopped = 1;
					usc_stop_transmitter(info);
				}
			}
		}
	}

	info->pending_bh |= BH_STATUS;
	
	/* for diagnostics set IRQ flag */
	if ( status & MISCSTATUS_TXC_LATCHED ){
		usc_OutReg( info, SICR,
			(unsigned short)(usc_InReg(info,SICR) & ~(SICR_TXC_ACTIVE+SICR_TXC_INACTIVE)) );
		usc_UnlatchIostatusBits( info, MISCSTATUS_TXC_LATCHED );
		info->irq_occurred = true;
	}

}	/* end of mgsl_isr_io_pin() */

/* mgsl_isr_transmit_data()
 * 
 * 	Service a transmit data interrupt (async mode only).
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_data( struct mgsl_struct *info )
{
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_transmit_data xmit_cnt=%d\n",
			__FILE__,__LINE__,info->xmit_cnt);
			
	usc_ClearIrqPendingBits( info, TRANSMIT_DATA );
	
	if (info->port.tty->stopped || info->port.tty->hw_stopped) {
		usc_stop_transmitter(info);
		return;
	}
	
	if ( info->xmit_cnt )
		usc_load_txfifo( info );
	else
		info->tx_active = false;
		
	if (info->xmit_cnt < WAKEUP_CHARS)
		info->pending_bh |= BH_TRANSMIT;

}	/* end of mgsl_isr_transmit_data() */

/* mgsl_isr_receive_data()
 * 
 * 	Service a receive data interrupt. This occurs
 * 	when operating in asynchronous interrupt transfer mode.
 *	The receive data FIFO is flushed to the receive data buffers. 
 * 
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_data( struct mgsl_struct *info )
{
	int Fifocount;
	u16 status;
	int work = 0;
	unsigned char DataByte;
 	struct tty_struct *tty = info->port.tty;
 	struct	mgsl_icount *icount = &info->icount;
	
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_receive_data\n",
			__FILE__,__LINE__);

	usc_ClearIrqPendingBits( info, RECEIVE_DATA );
	
	/* select FIFO status for RICR readback */
	usc_RCmd( info, RCmd_SelectRicrRxFifostatus );

	/* clear the Wordstatus bit so that status readback */
	/* only reflects the status of this byte */
	usc_OutReg( info, RICR+LSBONLY, (u16)(usc_InReg(info, RICR+LSBONLY) & ~BIT3 ));

	/* flush the receive FIFO */

	while( (Fifocount = (usc_InReg(info,RICR) >> 8)) ) {
		int flag;

		/* read one byte from RxFIFO */
		outw( (inw(info->io_base + CCAR) & 0x0780) | (RDR+LSBONLY),
		      info->io_base + CCAR );
		DataByte = inb( info->io_base + CCAR );

		/* get the status of the received byte */
		status = usc_InReg(info, RCSR);
		if ( status & (RXSTATUS_FRAMING_ERROR + RXSTATUS_PARITY_ERROR +
				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) )
			usc_UnlatchRxstatusBits(info,RXSTATUS_ALL);
		
		icount->rx++;
		
		flag = 0;
		if ( status & (RXSTATUS_FRAMING_ERROR + RXSTATUS_PARITY_ERROR +
				RXSTATUS_OVERRUN + RXSTATUS_BREAK_RECEIVED) ) {
			printk("rxerr=%04X\n",status);					
			/* update error statistics */
			if ( status & RXSTATUS_BREAK_RECEIVED ) {
				status &= ~(RXSTATUS_FRAMING_ERROR + RXSTATUS_PARITY_ERROR);
				icount->brk++;
			} else if (status & RXSTATUS_PARITY_ERROR) 
				icount->parity++;
			else if (status & RXSTATUS_FRAMING_ERROR)
				icount->frame++;
			else if (status & RXSTATUS_OVERRUN) {
				/* must issue purge fifo cmd before */
				/* 16C32 accepts more receive chars */
				usc_RTCmd(info,RTCmd_PurgeRxFifo);
				icount->overrun++;
			}

			/* discard char if tty control flags say so */					
			if (status & info->ignore_status_mask)
				continue;
				
			status &= info->read_status_mask;
		
			if (status & RXSTATUS_BREAK_RECEIVED) {
				flag = TTY_BREAK;
				if (info->port.flags & ASYNC_SAK)
					do_SAK(tty);
			} else if (status & RXSTATUS_PARITY_ERROR)
				flag = TTY_PARITY;
			else if (status & RXSTATUS_FRAMING_ERROR)
				flag = TTY_FRAME;
		}	/* end of if (error) */
		tty_insert_flip_char(tty, DataByte, flag);
		if (status & RXSTATUS_OVERRUN) {
			/* Overrun is special, since it's
			 * reported immediately, and doesn't
			 * affect the current character
			 */
			work += tty_insert_flip_char(tty, 0, TTY_OVERRUN);
		}
	}

	if ( debug_level >= DEBUG_LEVEL_ISR ) {
		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
			__FILE__,__LINE__,icount->rx,icount->brk,
			icount->parity,icount->frame,icount->overrun);
	}
			
	if(work)
		tty_flip_buffer_push(tty);
}

/* mgsl_isr_misc()
 * 
 * 	Service a miscellaneous interrupt source.
 * 	
 * Arguments:		info		pointer to device extension (instance data)
 * Return Value:	None
 */
static void mgsl_isr_misc( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, MISR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_misc status=%04X\n",
			__FILE__,__LINE__,status);
			
	if ((status & MISCSTATUS_RCC_UNDERRUN) &&
	    (info->params.mode == MGSL_MODE_HDLC)) {

		/* turn off receiver and rx DMA */
		usc_EnableReceiver(info,DISABLE_UNCONDITIONAL);
		usc_DmaCmd(info, DmaCmd_ResetRxChannel);
		usc_UnlatchRxstatusBits(info, RXSTATUS_ALL);
		usc_ClearIrqPendingBits(info, RECEIVE_DATA + RECEIVE_STATUS);
		usc_DisableInterrupts(info, RECEIVE_DATA + RECEIVE_STATUS);

		/* schedule BH handler to restart receiver */
		info->pending_bh |= BH_RECEIVE;
		info->rx_rcc_underrun = true;
	}

	usc_ClearIrqPendingBits( info, MISC );
	usc_UnlatchMiscstatusBits( info, status );

}	/* end of mgsl_isr_misc() */

/* mgsl_isr_null()
 *
 * 	Services undefined interrupt vectors from the
 * 	USC. (hence this function SHOULD never be called)
 * 
 * Arguments:		info		pointer to device extension (instance data)
 * Return Value:	None
 */
static void mgsl_isr_null( struct mgsl_struct *info )
{

}	/* end of mgsl_isr_null() */

/* mgsl_isr_receive_dma()
 * 
 * 	Service a receive DMA channel interrupt.
 * 	For this driver there are two sources of receive DMA interrupts
 * 	as identified in the Receive DMA mode Register (RDMR):
 * 
 * 	BIT3	EOA/EOL		End of List, all receive buffers in receive
 * 				buffer list have been filled (no more free buffers
 * 				available). The DMA controller has shut down.
 * 
 * 	BIT2	EOB		End of Buffer. This interrupt occurs when a receive
 * 				DMA buffer is terminated in response to completion
 * 				of a good frame or a frame with errors. The status
 * 				of the frame is stored in the buffer entry in the
 * 				list of receive buffer entries.
 * 
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_dma( struct mgsl_struct *info )
{
	u16 status;
	
	/* clear interrupt pending and IUS bit for Rx DMA IRQ */
	usc_OutDmaReg( info, CDIR, BIT9+BIT1 );

	/* Read the receive DMA status to identify interrupt type. */
	/* This also clears the status bits. */
	status = usc_InDmaReg( info, RDMR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_receive_dma(%s) status=%04X\n",
			__FILE__,__LINE__,info->device_name,status);
			
	info->pending_bh |= BH_RECEIVE;
	
	if ( status & BIT3 ) {
		info->rx_overflow = true;
		info->icount.buf_overrun++;
	}

}	/* end of mgsl_isr_receive_dma() */

/* mgsl_isr_transmit_dma()
 *
 *	This function services a transmit DMA channel interrupt.
 *
 *	For this driver there is one source of transmit DMA interrupts
 *	as identified in the Transmit DMA Mode Register (TDMR):
 *
 *     	BIT2  EOB       End of Buffer. This interrupt occurs when a
 *     			transmit DMA buffer has been emptied.
 *
 *     	The driver maintains enough transmit DMA buffers to hold at least
 *     	one max frame size transmit frame. When operating in a buffered
 *     	transmit mode, there may be enough transmit DMA buffers to hold at
 *     	least two or more max frame size frames. On an EOB condition,
 *     	determine if there are any queued transmit buffers and copy into
 *     	transmit DMA buffers if we have room.
 *
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_dma( struct mgsl_struct *info )
{
	u16 status;

	/* clear interrupt pending and IUS bit for Tx DMA IRQ */
	usc_OutDmaReg(info, CDIR, BIT8+BIT0 );

	/* Read the transmit DMA status to identify interrupt type. */
	/* This also clears the status bits. */

	status = usc_InDmaReg( info, TDMR );

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):mgsl_isr_transmit_dma(%s) status=%04X\n",
			__FILE__,__LINE__,info->device_name,status);

	if ( status & BIT2 ) {
		--info->tx_dma_buffers_used;

		/* if there are transmit frames queued,
		 *  try to load the next one
		 */
		if ( load_next_tx_holding_buffer(info) ) {
			/* if call returns non-zero value, we have
			 * at least one free tx holding buffer
			 */
			info->pending_bh |= BH_TRANSMIT;
		}
	}

}	/* end of mgsl_isr_transmit_dma() */

/* mgsl_interrupt()
 * 
 * 	Interrupt service routine entry point.
 * 	
 * Arguments:
 * 
 * 	irq		interrupt number that caused interrupt
 * 	dev_id		device ID supplied during interrupt registration
 * 	
 * Return Value: None
 */
static irqreturn_t mgsl_interrupt(int dummy, void *dev_id)
{
	struct mgsl_struct *info = dev_id;
	u16 UscVector;
	u16 DmaVector;

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk(KERN_DEBUG "%s(%d):mgsl_interrupt(%d)entry.\n",
			__FILE__, __LINE__, info->irq_level);

	spin_lock(&info->irq_spinlock);

	for(;;) {
		/* Read the interrupt vectors from hardware. */
		UscVector = usc_InReg(info, IVR) >> 9;
		DmaVector = usc_InDmaReg(info, DIVR);
		
		if ( debug_level >= DEBUG_LEVEL_ISR )	
			printk("%s(%d):%s UscVector=%08X DmaVector=%08X\n",
				__FILE__,__LINE__,info->device_name,UscVector,DmaVector);
			
		if ( !UscVector && !DmaVector )
			break;
			
		/* Dispatch interrupt vector */
		if ( UscVector )
			(*UscIsrTable[UscVector])(info);
		else if ( (DmaVector&(BIT10|BIT9)) == BIT10)
			mgsl_isr_transmit_dma(info);
		else
			mgsl_isr_receive_dma(info);

		if ( info->isr_overflow ) {
			printk(KERN_ERR "%s(%d):%s isr overflow irq=%d\n",
				__FILE__, __LINE__, info->device_name, info->irq_level);
			usc_DisableMasterIrqBit(info);
			usc_DisableDmaInterrupts(info,DICR_MASTER);
			break;
		}
	}
	
	/* Request bottom half processing if there's something 
	 * for it to do and the bh is not already running
	 */

	if ( info->pending_bh && !info->bh_running && !info->bh_requested ) {
		if ( debug_level >= DEBUG_LEVEL_ISR )	
			printk("%s(%d):%s queueing bh task.\n",
				__FILE__,__LINE__,info->device_name);
		schedule_work(&info->task);
		info->bh_requested = true;
	}

	spin_unlock(&info->irq_spinlock);
	
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk(KERN_DEBUG "%s(%d):mgsl_interrupt(%d)exit.\n",
			__FILE__, __LINE__, info->irq_level);

	return IRQ_HANDLED;
}	/* end of mgsl_interrupt() */

/* startup()
 * 
 * 	Initialize and start device.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	0 if success, otherwise error code
 */
static int startup(struct mgsl_struct * info)
{
	int retval = 0;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("%s(%d):mgsl_startup(%s)\n",__FILE__,__LINE__,info->device_name);
		
	if (info->port.flags & ASYNC_INITIALIZED)
		return 0;
	
	if (!info->xmit_buf) {
		/* allocate a page of memory for a transmit buffer */
		info->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
		if (!info->xmit_buf) {
			printk(KERN_ERR"%s(%d):%s can't allocate transmit buffer\n",
				__FILE__,__LINE__,info->device_name);
			return -ENOMEM;
		}
	}

	info->pending_bh = 0;
	
	memset(&info->icount, 0, sizeof(info->icount));

	setup_timer(&info->tx_timer, mgsl_tx_timeout, (unsigned long)info);
	
	/* Allocate and claim adapter resources */
	retval = mgsl_claim_resources(info);
	
	/* perform existence check and diagnostics */
	if ( !retval )
		retval = mgsl_adapter_test(info);
		
	if ( retval ) {
  		if (capable(CAP_SYS_ADMIN) && info->port.tty)
			set_bit(TTY_IO_ERROR, &info->port.tty->flags);
		mgsl_release_resources(info);
  		return retval;
  	}

	/* program hardware for current parameters */
	mgsl_change_params(info);
	
	if (info->port.tty)
		clear_bit(TTY_IO_ERROR, &info->port.tty->flags);

	info->port.flags |= ASYNC_INITIALIZED;
	
	return 0;
	
}	/* end of startup() */

/* shutdown()
 *
 * Called by mgsl_close() and mgsl_hangup() to shutdown hardware
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void shutdown(struct mgsl_struct * info)
{
	unsigned long flags;
	
	if (!(info->port.flags & ASYNC_INITIALIZED))
		return;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_shutdown(%s)\n",
			 __FILE__,__LINE__, info->device_name );

	/* clear status wait queue because status changes */
	/* can't happen after shutting down the hardware */
	wake_up_interruptible(&info->status_event_wait_q);
	wake_up_interruptible(&info->event_wait_q);

	del_timer_sync(&info->tx_timer);

	if (info->xmit_buf) {
		free_page((unsigned long) info->xmit_buf);
		info->xmit_buf = NULL;
	}

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_DisableMasterIrqBit(info);
	usc_stop_receiver(info);
	usc_stop_transmitter(info);
	usc_DisableInterrupts(info,RECEIVE_DATA + RECEIVE_STATUS +
		TRANSMIT_DATA + TRANSMIT_STATUS + IO_PIN + MISC );
	usc_DisableDmaInterrupts(info,DICR_MASTER + DICR_TRANSMIT + DICR_RECEIVE);
	
	/* Disable DMAEN (Port 7, Bit 14) */
	/* This disconnects the DMA request signal from the ISA bus */
	/* on the ISA adapter. This has no effect for the PCI adapter */
	usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT15) | BIT14));
	
	/* Disable INTEN (Port 6, Bit12) */
	/* This disconnects the IRQ request signal to the ISA bus */
	/* on the ISA adapter. This has no effect for the PCI adapter */
	usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT13) | BIT12));
	
 	if (!info->port.tty || info->port.tty->termios->c_cflag & HUPCL) {
 		info->serial_signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
		usc_set_serial_signals(info);
	}
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	mgsl_release_resources(info);	
	
	if (info->port.tty)
		set_bit(TTY_IO_ERROR, &info->port.tty->flags);

	info->port.flags &= ~ASYNC_INITIALIZED;
	
}	/* end of shutdown() */

static void mgsl_program_hw(struct mgsl_struct *info)
{
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	
	usc_stop_receiver(info);
	usc_stop_transmitter(info);
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	
	if (info->params.mode == MGSL_MODE_HDLC ||
	    info->params.mode == MGSL_MODE_RAW ||
	    info->netcount)
		usc_set_sync_mode(info);
	else
		usc_set_async_mode(info);
		
	usc_set_serial_signals(info);
	
	info->dcd_chkcount = 0;
	info->cts_chkcount = 0;
	info->ri_chkcount = 0;
	info->dsr_chkcount = 0;

	usc_EnableStatusIrqs(info,SICR_CTS+SICR_DSR+SICR_DCD+SICR_RI);		
	usc_EnableInterrupts(info, IO_PIN);
	usc_get_serial_signals(info);
		
	if (info->netcount || info->port.tty->termios->c_cflag & CREAD)
		usc_start_receiver(info);
		
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}

/* Reconfigure adapter based on new parameters
 */
static void mgsl_change_params(struct mgsl_struct *info)
{
	unsigned cflag;
	int bits_per_char;

	if (!info->port.tty || !info->port.tty->termios)
		return;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_change_params(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	cflag = info->port.tty->termios->c_cflag;

	/* if B0 rate (hangup) specified then negate DTR and RTS */
	/* otherwise assert DTR and RTS */
 	if (cflag & CBAUD)
		info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
	else
		info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
	
	/* byte size and parity */
	
	switch (cflag & CSIZE) {
	      case CS5: info->params.data_bits = 5; break;
	      case CS6: info->params.data_bits = 6; break;
	      case CS7: info->params.data_bits = 7; break;
	      case CS8: info->params.data_bits = 8; break;
	      /* Never happens, but GCC is too dumb to figure it out */
	      default:  info->params.data_bits = 7; break;
	      }
	      
	if (cflag & CSTOPB)
		info->params.stop_bits = 2;
	else
		info->params.stop_bits = 1;

	info->params.parity = ASYNC_PARITY_NONE;
	if (cflag & PARENB) {
		if (cflag & PARODD)
			info->params.parity = ASYNC_PARITY_ODD;
		else
			info->params.parity = ASYNC_PARITY_EVEN;
#ifdef CMSPAR
		if (cflag & CMSPAR)
			info->params.parity = ASYNC_PARITY_SPACE;
#endif
	}

	/* calculate number of jiffies to transmit a full
	 * FIFO (32 bytes) at specified data rate
	 */
	bits_per_char = info->params.data_bits + 
			info->params.stop_bits + 1;

	/* if port data rate is set to 460800 or less then
	 * allow tty settings to override, otherwise keep the
	 * current data rate.
	 */
	if (info->params.data_rate <= 460800)
		info->params.data_rate = tty_get_baud_rate(info->port.tty);
	
	if ( info->params.data_rate ) {
		info->timeout = (32*HZ*bits_per_char) / 
				info->params.data_rate;
	}
	info->timeout += HZ/50;		/* Add .02 seconds of slop */

	if (cflag & CRTSCTS)
		info->port.flags |= ASYNC_CTS_FLOW;
	else
		info->port.flags &= ~ASYNC_CTS_FLOW;
		
	if (cflag & CLOCAL)
		info->port.flags &= ~ASYNC_CHECK_CD;
	else
		info->port.flags |= ASYNC_CHECK_CD;

	/* process tty input control flags */
	
	info->read_status_mask = RXSTATUS_OVERRUN;
	if (I_INPCK(info->port.tty))
		info->read_status_mask |= RXSTATUS_PARITY_ERROR | RXSTATUS_FRAMING_ERROR;
 	if (I_BRKINT(info->port.tty) || I_PARMRK(info->port.tty))
 		info->read_status_mask |= RXSTATUS_BREAK_RECEIVED;
	
	if (I_IGNPAR(info->port.tty))
		info->ignore_status_mask |= RXSTATUS_PARITY_ERROR | RXSTATUS_FRAMING_ERROR;
	if (I_IGNBRK(info->port.tty)) {
		info->ignore_status_mask |= RXSTATUS_BREAK_RECEIVED;
		/* If ignoring parity and break indicators, ignore 
		 * overruns too.  (For real raw support).
		 */
		if (I_IGNPAR(info->port.tty))
			info->ignore_status_mask |= RXSTATUS_OVERRUN;
	}

	mgsl_program_hw(info);

}	/* end of mgsl_change_params() */

/* mgsl_put_char()
 * 
 * 	Add a character to the transmit buffer.
 * 	
 * Arguments:		tty	pointer to tty information structure
 * 			ch	character to add to transmit buffer
 * 		
 * Return Value:	None
 */
static int mgsl_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	int ret = 0;

	if (debug_level >= DEBUG_LEVEL_INFO) {
		printk(KERN_DEBUG "%s(%d):mgsl_put_char(%d) on %s\n",
			__FILE__, __LINE__, ch, info->device_name);
	}		
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_put_char"))
		return 0;

	if (!tty || !info->xmit_buf)
		return 0;

	spin_lock_irqsave(&info->irq_spinlock, flags);
	
	if ((info->params.mode == MGSL_MODE_ASYNC ) || !info->tx_active) {
		if (info->xmit_cnt < SERIAL_XMIT_SIZE - 1) {
			info->xmit_buf[info->xmit_head++] = ch;
			info->xmit_head &= SERIAL_XMIT_SIZE-1;
			info->xmit_cnt++;
			ret = 1;
		}
	}
	spin_unlock_irqrestore(&info->irq_spinlock, flags);
	return ret;
	
}	/* end of mgsl_put_char() */

/* mgsl_flush_chars()
 * 
 * 	Enable transmitter so remaining characters in the
 * 	transmit buffer are sent.
 * 	
 * Arguments:		tty	pointer to tty information structure
 * Return Value:	None
 */
static void mgsl_flush_chars(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
				
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_flush_chars() entry on %s xmit_cnt=%d\n",
			__FILE__,__LINE__,info->device_name,info->xmit_cnt);
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_flush_chars"))
		return;

	if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
	    !info->xmit_buf)
		return;

	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_flush_chars() entry on %s starting transmitter\n",
			__FILE__,__LINE__,info->device_name );

	spin_lock_irqsave(&info->irq_spinlock,flags);
	
	if (!info->tx_active) {
		if ( (info->params.mode == MGSL_MODE_HDLC ||
			info->params.mode == MGSL_MODE_RAW) && info->xmit_cnt ) {
			/* operating in synchronous (frame oriented) mode */
			/* copy data from circular xmit_buf to */
			/* transmit DMA buffer. */
			mgsl_load_tx_dma_buffer(info,
				 info->xmit_buf,info->xmit_cnt);
		}
	 	usc_start_transmitter(info);
	}
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_flush_chars() */

/* mgsl_write()
 * 
 * 	Send a block of data
 * 	
 * Arguments:
 * 
 * 	tty		pointer to tty information structure
 * 	buf		pointer to buffer containing send data
 * 	count		size of send data in bytes
 * 	
 * Return Value:	number of characters written
 */
static int mgsl_write(struct tty_struct * tty,
		    const unsigned char *buf, int count)
{
	int	c, ret = 0;
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_write(%s) count=%d\n",
			__FILE__,__LINE__,info->device_name,count);
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_write"))
		goto cleanup;

	if (!tty || !info->xmit_buf)
		goto cleanup;

	if ( info->params.mode == MGSL_MODE_HDLC ||
			info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		/* operating in synchronous (frame oriented) mode */
		if (info->tx_active) {

			if ( info->params.mode == MGSL_MODE_HDLC ) {
				ret = 0;
				goto cleanup;
			}
			/* transmitter is actively sending data -
			 * if we have multiple transmit dma and
			 * holding buffers, attempt to queue this
			 * frame for transmission at a later time.
			 */
			if (info->tx_holding_count >= info->num_tx_holding_buffers ) {
				/* no tx holding buffers available */
				ret = 0;
				goto cleanup;
			}

			/* queue transmit frame request */
			ret = count;
			save_tx_buffer_request(info,buf,count);

			/* if we have sufficient tx dma buffers,
			 * load the next buffered tx request
			 */
			spin_lock_irqsave(&info->irq_spinlock,flags);
			load_next_tx_holding_buffer(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			goto cleanup;
		}
	
		/* if operating in HDLC LoopMode and the adapter  */
		/* has yet to be inserted into the loop, we can't */
		/* transmit					  */

		if ( (info->params.flags & HDLC_FLAG_HDLC_LOOPMODE) &&
			!usc_loopmode_active(info) )
		{
			ret = 0;
			goto cleanup;
		}

		if ( info->xmit_cnt ) {
			/* Send accumulated from send_char() calls */
			/* as frame and wait before accepting more data. */
			ret = 0;
			
			/* copy data from circular xmit_buf to */
			/* transmit DMA buffer. */
			mgsl_load_tx_dma_buffer(info,
				info->xmit_buf,info->xmit_cnt);
			if ( debug_level >= DEBUG_LEVEL_INFO )
				printk( "%s(%d):mgsl_write(%s) sync xmit_cnt flushing\n",
					__FILE__,__LINE__,info->device_name);
		} else {
			if ( debug_level >= DEBUG_LEVEL_INFO )
				printk( "%s(%d):mgsl_write(%s) sync transmit accepted\n",
					__FILE__,__LINE__,info->device_name);
			ret = count;
			info->xmit_cnt = count;
			mgsl_load_tx_dma_buffer(info,buf,count);
		}
	} else {
		while (1) {
			spin_lock_irqsave(&info->irq_spinlock,flags);
			c = min_t(int, count,
				min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				    SERIAL_XMIT_SIZE - info->xmit_head));
			if (c <= 0) {
				spin_unlock_irqrestore(&info->irq_spinlock,flags);
				break;
			}
			memcpy(info->xmit_buf + info->xmit_head, buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			buf += c;
			count -= c;
			ret += c;
		}
	}	
	
 	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!info->tx_active)
		 	usc_start_transmitter(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
 	}
cleanup:	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_write(%s) returning=%d\n",
			__FILE__,__LINE__,info->device_name,ret);
			
	return ret;
	
}	/* end of mgsl_write() */

/* mgsl_write_room()
 *
 *	Return the count of free bytes in transmit buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static int mgsl_write_room(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	int	ret;
				
	if (mgsl_paranoia_check(info, tty->name, "mgsl_write_room"))
		return 0;
	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)
		ret = 0;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_write_room(%s)=%d\n",
			 __FILE__,__LINE__, info->device_name,ret );
			 
	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		if ( info->tx_active )
			return 0;
		else
			return HDLC_MAX_FRAME_SIZE;
	}
	
	return ret;
	
}	/* end of mgsl_write_room() */

/* mgsl_chars_in_buffer()
 *
 *	Return the count of bytes in transmit buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static int mgsl_chars_in_buffer(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
			 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_chars_in_buffer(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_chars_in_buffer"))
		return 0;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_chars_in_buffer(%s)=%d\n",
			 __FILE__,__LINE__, info->device_name,info->xmit_cnt );
			 
	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		if ( info->tx_active )
			return info->max_frame_size;
		else
			return 0;
	}
			 
	return info->xmit_cnt;
}	/* end of mgsl_chars_in_buffer() */

/* mgsl_flush_buffer()
 *
 *	Discard all data in the send buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_flush_buffer(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_flush_buffer(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_flush_buffer"))
		return;
		
	spin_lock_irqsave(&info->irq_spinlock,flags); 
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	del_timer(&info->tx_timer);	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
	tty_wakeup(tty);
}

/* mgsl_send_xchar()
 *
 *	Send a high-priority XON/XOFF character
 * 	
 * Arguments:		tty	pointer to tty info structure
 *			ch	character to send
 * Return Value:	None
 */
static void mgsl_send_xchar(struct tty_struct *tty, char ch)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_send_xchar(%s,%d)\n",
			 __FILE__,__LINE__, info->device_name, ch );
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_send_xchar"))
		return;

	info->x_char = ch;
	if (ch) {
		/* Make sure transmit interrupts are on */
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!info->tx_enabled)
		 	usc_start_transmitter(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
}	/* end of mgsl_send_xchar() */

/* mgsl_throttle()
 * 
 * 	Signal remote device to throttle send data (our receive data)
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_throttle(struct tty_struct * tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_throttle(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );

	if (mgsl_paranoia_check(info, tty->name, "mgsl_throttle"))
		return;
	
	if (I_IXOFF(tty))
		mgsl_send_xchar(tty, STOP_CHAR(tty));
 
 	if (tty->termios->c_cflag & CRTSCTS) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		info->serial_signals &= ~SerialSignal_RTS;
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
}	/* end of mgsl_throttle() */

/* mgsl_unthrottle()
 * 
 * 	Signal remote device to stop throttling send data (our receive data)
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_unthrottle(struct tty_struct * tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_unthrottle(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );

	if (mgsl_paranoia_check(info, tty->name, "mgsl_unthrottle"))
		return;
	
	if (I_IXOFF(tty)) {
		if (info->x_char)
			info->x_char = 0;
		else
			mgsl_send_xchar(tty, START_CHAR(tty));
	}
	
 	if (tty->termios->c_cflag & CRTSCTS) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		info->serial_signals |= SerialSignal_RTS;
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
	
}	/* end of mgsl_unthrottle() */

/* mgsl_get_stats()
 * 
 * 	get the current serial parameters information
 *
 * Arguments:	info		pointer to device instance data
 * 		user_icount	pointer to buffer to hold returned stats
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_stats(struct mgsl_struct * info, struct mgsl_icount __user *user_icount)
{
	int err;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_params(%s)\n",
			 __FILE__,__LINE__, info->device_name);
			
	if (!user_icount) {
		memset(&info->icount, 0, sizeof(info->icount));
	} else {
		COPY_TO_USER(err, user_icount, &info->icount, sizeof(struct mgsl_icount));
		if (err)
			return -EFAULT;
	}
	
	return 0;
	
}	/* end of mgsl_get_stats() */

/* mgsl_get_params()
 * 
 * 	get the current serial parameters information
 *
 * Arguments:	info		pointer to device instance data
 * 		user_params	pointer to buffer to hold returned params
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_params(struct mgsl_struct * info, MGSL_PARAMS __user *user_params)
{
	int err;
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_params(%s)\n",
			 __FILE__,__LINE__, info->device_name);
			
	COPY_TO_USER(err,user_params, &info->params, sizeof(MGSL_PARAMS));
	if (err) {
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk( "%s(%d):mgsl_get_params(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	return 0;
	
}	/* end of mgsl_get_params() */

/* mgsl_set_params()
 * 
 * 	set the serial parameters
 * 	
 * Arguments:
 * 
 * 	info		pointer to device instance data
 * 	new_params	user buffer containing new serial params
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_set_params(struct mgsl_struct * info, MGSL_PARAMS __user *new_params)
{
 	unsigned long flags;
	MGSL_PARAMS tmp_params;
	int err;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_set_params %s\n", __FILE__,__LINE__,
			info->device_name );
	COPY_FROM_USER(err,&tmp_params, new_params, sizeof(MGSL_PARAMS));
	if (err) {
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk( "%s(%d):mgsl_set_params(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	spin_lock_irqsave(&info->irq_spinlock,flags);
	memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
 	mgsl_change_params(info);
	
	return 0;
	
}	/* end of mgsl_set_params() */

/* mgsl_get_txidle()
 * 
 * 	get the current transmit idle mode
 *
 * Arguments:	info		pointer to device instance data
 * 		idle_mode	pointer to buffer to hold returned idle mode
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_txidle(struct mgsl_struct * info, int __user *idle_mode)
{
	int err;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_txidle(%s)=%d\n",
			 __FILE__,__LINE__, info->device_name, info->idle_mode);
			
	COPY_TO_USER(err,idle_mode, &info->idle_mode, sizeof(int));
	if (err) {
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk( "%s(%d):mgsl_get_txidle(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	return 0;
	
}	/* end of mgsl_get_txidle() */

/* mgsl_set_txidle()	service ioctl to set transmit idle mode
 * 	
 * Arguments:	 	info		pointer to device instance data
 * 			idle_mode	new idle mode
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_set_txidle(struct mgsl_struct * info, int idle_mode)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_set_txidle(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, idle_mode );
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	info->idle_mode = idle_mode;
	usc_set_txidle( info );
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_set_txidle() */

/* mgsl_txenable()
 * 
 * 	enable or disable the transmitter
 * 	
 * Arguments:
 * 
 * 	info		pointer to device instance data
 * 	enable		1 = enable, 0 = disable
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_txenable(struct mgsl_struct * info, int enable)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_txenable(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, enable);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( enable ) {
		if ( !info->tx_enabled ) {

			usc_start_transmitter(info);
			/*--------------------------------------------------
			 * if HDLC/SDLC Loop mode, attempt to insert the
			 * station in the 'loop' by setting CMR:13. Upon
			 * receipt of the next GoAhead (RxAbort) sequence,
			 * the OnLoop indicator (CCSR:7) should go active
			 * to indicate that we are on the loop
			 *--------------------------------------------------*/
			if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
				usc_loopmode_insert_request( info );
		}
	} else {
		if ( info->tx_enabled )
			usc_stop_transmitter(info);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_txenable() */

/* mgsl_txabort()	abort send HDLC frame
 * 	
 * Arguments:	 	info		pointer to device instance data
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_txabort(struct mgsl_struct * info)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_txabort(%s)\n", __FILE__,__LINE__,
			info->device_name);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( info->tx_active && info->params.mode == MGSL_MODE_HDLC )
	{
		if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
			usc_loopmode_cancel_transmit( info );
		else
			usc_TCmd(info,TCmd_SendAbort);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_txabort() */

/* mgsl_rxenable() 	enable or disable the receiver
 * 	
 * Arguments:	 	info		pointer to device instance data
 * 			enable		1 = enable, 0 = disable
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_rxenable(struct mgsl_struct * info, int enable)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_rxenable(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, enable);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( enable ) {
		if ( !info->rx_enabled )
			usc_start_receiver(info);
	} else {
		if ( info->rx_enabled )
			usc_stop_receiver(info);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_rxenable() */

/* mgsl_wait_event() 	wait for specified event to occur
 * 	
 * Arguments:	 	info	pointer to device instance data
 * 			mask	pointer to bitmask of events to wait for
 * Return Value:	0 	if successful and bit mask updated with
 *				of events triggerred,
 * 			otherwise error code
 */
static int mgsl_wait_event(struct mgsl_struct * info, int __user * mask_ptr)
{
 	unsigned long flags;
	int s;
	int rc=0;
	struct mgsl_icount cprev, cnow;
	int events;
	int mask;
	struct	_input_signal_events oldsigs, newsigs;
	DECLARE_WAITQUEUE(wait, current);

	COPY_FROM_USER(rc,&mask, mask_ptr, sizeof(int));
	if (rc) {
		return  -EFAULT;
	}
		 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_wait_event(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, mask);

	spin_lock_irqsave(&info->irq_spinlock,flags);

	/* return immediately if state matches requested events */
	usc_get_serial_signals(info);
	s = info->serial_signals;
	events = mask &
		( ((s & SerialSignal_DSR) ? MgslEvent_DsrActive:MgslEvent_DsrInactive) +
 		  ((s & SerialSignal_DCD) ? MgslEvent_DcdActive:MgslEvent_DcdInactive) +
		  ((s & SerialSignal_CTS) ? MgslEvent_CtsActive:MgslEvent_CtsInactive) +
		  ((s & SerialSignal_RI)  ? MgslEvent_RiActive :MgslEvent_RiInactive) );
	if (events) {
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
		goto exit;
	}

	/* save current irq counts */
	cprev = info->icount;
	oldsigs = info->input_signal_events;
	
	/* enable hunt and idle irqs if needed */
	if (mask & (MgslEvent_ExitHuntMode + MgslEvent_IdleReceived)) {
		u16 oldreg = usc_InReg(info,RICR);
		u16 newreg = oldreg +
			 (mask & MgslEvent_ExitHuntMode ? RXSTATUS_EXITED_HUNT:0) +
			 (mask & MgslEvent_IdleReceived ? RXSTATUS_IDLE_RECEIVED:0);
		if (oldreg != newreg)
			usc_OutReg(info, RICR, newreg);
	}
	
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&info->event_wait_q, &wait);
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	

	for(;;) {
		schedule();
		if (signal_pending(current)) {
			rc = -ERESTARTSYS;
			break;
		}
			
		/* get current irq counts */
		spin_lock_irqsave(&info->irq_spinlock,flags);
		cnow = info->icount;
		newsigs = info->input_signal_events;
		set_current_state(TASK_INTERRUPTIBLE);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);

		/* if no change, wait aborted for some reason */
		if (newsigs.dsr_up   == oldsigs.dsr_up   &&
		    newsigs.dsr_down == oldsigs.dsr_down &&
		    newsigs.dcd_up   == oldsigs.dcd_up   &&
		    newsigs.dcd_down == oldsigs.dcd_down &&
		    newsigs.cts_up   == oldsigs.cts_up   &&
		    newsigs.cts_down == oldsigs.cts_down &&
		    newsigs.ri_up    == oldsigs.ri_up    &&
		    newsigs.ri_down  == oldsigs.ri_down  &&
		    cnow.exithunt    == cprev.exithunt   &&
		    cnow.rxidle      == cprev.rxidle) {
			rc = -EIO;
			break;
		}

		events = mask &
			( (newsigs.dsr_up   != oldsigs.dsr_up   ? MgslEvent_DsrActive:0)   +
			(newsigs.dsr_down != oldsigs.dsr_down ? MgslEvent_DsrInactive:0) +
			(newsigs.dcd_up   != oldsigs.dcd_up   ? MgslEvent_DcdActive:0)   +
			(newsigs.dcd_down != oldsigs.dcd_down ? MgslEvent_DcdInactive:0) +
			(newsigs.cts_up   != oldsigs.cts_up   ? MgslEvent_CtsActive:0)   +
			(newsigs.cts_down != oldsigs.cts_down ? MgslEvent_CtsInactive:0) +
			(newsigs.ri_up    != oldsigs.ri_up    ? MgslEvent_RiActive:0)    +
			(newsigs.ri_down  != oldsigs.ri_down  ? MgslEvent_RiInactive:0)  +
			(cnow.exithunt    != cprev.exithunt   ? MgslEvent_ExitHuntMode:0) +
			  (cnow.rxidle      != cprev.rxidle     ? MgslEvent_IdleReceived:0) );
		if (events)
			break;
		
		cprev = cnow;
		oldsigs = newsigs;
	}
	
	remove_wait_queue(&info->event_wait_q, &wait);
	set_current_state(TASK_RUNNING);

	if (mask & (MgslEvent_ExitHuntMode + MgslEvent_IdleReceived)) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!waitqueue_active(&info->event_wait_q)) {
			/* disable enable exit hunt mode/idle rcvd IRQs */
			usc_OutReg(info, RICR, usc_InReg(info,RICR) &
				~(RXSTATUS_EXITED_HUNT + RXSTATUS_IDLE_RECEIVED));
		}
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
exit:
	if ( rc == 0 )
		PUT_USER(rc, events, mask_ptr);
		
	return rc;
	
}	/* end of mgsl_wait_event() */

static int modem_input_wait(struct mgsl_struct *info,int arg)
{
 	unsigned long flags;
	int rc;
	struct mgsl_icount cprev, cnow;
	DECLARE_WAITQUEUE(wait, current);

	/* save current irq counts */
	spin_lock_irqsave(&info->irq_spinlock,flags);
	cprev = info->icount;
	add_wait_queue(&info->status_event_wait_q, &wait);
	set_current_state(TASK_INTERRUPTIBLE);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	for(;;) {
		schedule();
		if (signal_pending(current)) {
			rc = -ERESTARTSYS;
			break;
		}

		/* get new irq counts */
		spin_lock_irqsave(&info->irq_spinlock,flags);
		cnow = info->icount;
		set_current_state(TASK_INTERRUPTIBLE);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);

		/* if no change, wait aborted for some reason */
		if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
		    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
			rc = -EIO;
			break;
		}

		/* check for change in caller specified modem input */
		if ((arg & TIOCM_RNG && cnow.rng != cprev.rng) ||
		    (arg & TIOCM_DSR && cnow.dsr != cprev.dsr) ||
		    (arg & TIOCM_CD  && cnow.dcd != cprev.dcd) ||
		    (arg & TIOCM_CTS && cnow.cts != cprev.cts)) {
			rc = 0;
			break;
		}

		cprev = cnow;
	}
	remove_wait_queue(&info->status_event_wait_q, &wait);
	set_current_state(TASK_RUNNING);
	return rc;
}

/* return the state of the serial control and status signals
 */
static int tiocmget(struct tty_struct *tty, struct file *file)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned int result;
 	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
 	usc_get_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	result = ((info->serial_signals & SerialSignal_RTS) ? TIOCM_RTS:0) +
		((info->serial_signals & SerialSignal_DTR) ? TIOCM_DTR:0) +
		((info->serial_signals & SerialSignal_DCD) ? TIOCM_CAR:0) +
		((info->serial_signals & SerialSignal_RI)  ? TIOCM_RNG:0) +
		((info->serial_signals & SerialSignal_DSR) ? TIOCM_DSR:0) +
		((info->serial_signals & SerialSignal_CTS) ? TIOCM_CTS:0);

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s tiocmget() value=%08X\n",
			 __FILE__,__LINE__, info->device_name, result );
	return result;
}

/* set modem control signals (DTR/RTS)
 */
static int tiocmset(struct tty_struct *tty, struct file *file,
		    unsigned int set, unsigned int clear)
{
	struct mgsl_struct *info = tty->driver_data;
 	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s tiocmset(%x,%x)\n",
			__FILE__,__LINE__,info->device_name, set, clear);

	if (set & TIOCM_RTS)
		info->serial_signals |= SerialSignal_RTS;
	if (set & TIOCM_DTR)
		info->serial_signals |= SerialSignal_DTR;
	if (clear & TIOCM_RTS)
		info->serial_signals &= ~SerialSignal_RTS;
	if (clear & TIOCM_DTR)
		info->serial_signals &= ~SerialSignal_DTR;

	spin_lock_irqsave(&info->irq_spinlock,flags);
 	usc_set_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	return 0;
}

/* mgsl_break()		Set or clear transmit break condition
 *
 * Arguments:		tty		pointer to tty instance data
 *			break_state	-1=set break condition, 0=clear
 * Return Value:	error code
 */
static int mgsl_break(struct tty_struct *tty, int break_state)
{
	struct mgsl_struct * info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_break(%s,%d)\n",
			 __FILE__,__LINE__, info->device_name, break_state);
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_break"))
		return -EINVAL;

	spin_lock_irqsave(&info->irq_spinlock,flags);
 	if (break_state == -1)
		usc_OutReg(info,IOCR,(u16)(usc_InReg(info,IOCR) | BIT7));
	else 
		usc_OutReg(info,IOCR,(u16)(usc_InReg(info,IOCR) & ~BIT7));
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_break() */

/* mgsl_ioctl()	Service an IOCTL request
 * 	
 * Arguments:
 * 
 * 	tty	pointer to tty instance data
 * 	file	pointer to associated file object for device
 * 	cmd	IOCTL command code
 * 	arg	command argument/context
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_ioctl(struct tty_struct *tty, struct file * file,
		    unsigned int cmd, unsigned long arg)
{
	struct mgsl_struct * info = tty->driver_data;
	int ret;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_ioctl %s cmd=%08X\n", __FILE__,__LINE__,
			info->device_name, cmd );
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_ioctl"))
		return -ENODEV;

	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
		if (tty->flags & (1 << TTY_IO_ERROR))
		    return -EIO;
	}

	lock_kernel();
	ret = mgsl_ioctl_common(info, cmd, arg);
	unlock_kernel();
	return ret;
}

static int mgsl_ioctl_common(struct mgsl_struct *info, unsigned int cmd, unsigned long arg)
{
	int error;
	struct mgsl_icount cnow;	/* kernel counter temps */
	void __user *argp = (void __user *)arg;
	struct serial_icounter_struct __user *p_cuser;	/* user space */
	unsigned long flags;
	
	switch (cmd) {
		case MGSL_IOCGPARAMS:
			return mgsl_get_params(info, argp);
		case MGSL_IOCSPARAMS:
			return mgsl_set_params(info, argp);
		case MGSL_IOCGTXIDLE:
			return mgsl_get_txidle(info, argp);
		case MGSL_IOCSTXIDLE:
			return mgsl_set_txidle(info,(int)arg);
		case MGSL_IOCTXENABLE:
			return mgsl_txenable(info,(int)arg);
		case MGSL_IOCRXENABLE:
			return mgsl_rxenable(info,(int)arg);
		case MGSL_IOCTXABORT:
			return mgsl_txabort(info);
		case MGSL_IOCGSTATS:
			return mgsl_get_stats(info, argp);
		case MGSL_IOCWAITEVENT:
			return mgsl_wait_event(info, argp);
		case MGSL_IOCLOOPTXDONE:
			return mgsl_loopmode_send_done(info);
		/* Wait for modem input (DCD,RI,DSR,CTS) change
		 * as specified by mask in arg (TIOCM_RNG/DSR/CD/CTS)
		 */
		case TIOCMIWAIT:
			return modem_input_wait(info,(int)arg);

		/* 
		 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
		 * Return: write counters to the user passed counter struct
		 * NB: both 1->0 and 0->1 transitions are counted except for
		 *     RI where only 0->1 is counted.
		 */
		case TIOCGICOUNT:
			spin_lock_irqsave(&info->irq_spinlock,flags);
			cnow = info->icount;
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			p_cuser = argp;
			PUT_USER(error,cnow.cts, &p_cuser->cts);
			if (error) return error;
			PUT_USER(error,cnow.dsr, &p_cuser->dsr);
			if (error) return error;
			PUT_USER(error,cnow.rng, &p_cuser->rng);
			if (error) return error;
			PUT_USER(error,cnow.dcd, &p_cuser->dcd);
			if (error) return error;
			PUT_USER(error,cnow.rx, &p_cuser->rx);
			if (error) return error;
			PUT_USER(error,cnow.tx, &p_cuser->tx);
			if (error) return error;
			PUT_USER(error,cnow.frame, &p_cuser->frame);
			if (error) return error;
			PUT_USER(error,cnow.overrun, &p_cuser->overrun);
			if (error) return error;
			PUT_USER(error,cnow.parity, &p_cuser->parity);
			if (error) return error;
			PUT_USER(error,cnow.brk, &p_cuser->brk);
			if (error) return error;
			PUT_USER(error,cnow.buf_overrun, &p_cuser->buf_overrun);
			if (error) return error;
			return 0;
		default:
			return -ENOIOCTLCMD;
	}
	return 0;
}

/* mgsl_set_termios()
 * 
 * 	Set new termios settings
 * 	
 * Arguments:
 * 
 * 	tty		pointer to tty structure
 * 	termios		pointer to buffer to hold returned old termios
 * 	
 * Return Value:		None
 */
static void mgsl_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_set_termios %s\n", __FILE__,__LINE__,
			tty->driver->name );
	
	mgsl_change_params(info);

	/* Handle transition to B0 status */
	if (old_termios->c_cflag & CBAUD &&
	    !(tty->termios->c_cflag & CBAUD)) {
		info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
		spin_lock_irqsave(&info->irq_spinlock,flags);
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
	
	/* Handle transition away from B0 status */
	if (!(old_termios->c_cflag & CBAUD) &&
	    tty->termios->c_cflag & CBAUD) {
		info->serial_signals |= SerialSignal_DTR;
 		if (!(tty->termios->c_cflag & CRTSCTS) || 
 		    !test_bit(TTY_THROTTLED, &tty->flags)) {
			info->serial_signals |= SerialSignal_RTS;
 		}
		spin_lock_irqsave(&info->irq_spinlock,flags);
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
	
	/* Handle turning off CRTSCTS */
	if (old_termios->c_cflag & CRTSCTS &&
	    !(tty->termios->c_cflag & CRTSCTS)) {
		tty->hw_stopped = 0;
		mgsl_start(tty);
	}

}	/* end of mgsl_set_termios() */

/* mgsl_close()
 * 
 * 	Called when port is closed. Wait for remaining data to be
 * 	sent. Disable port and free resources.
 * 	
 * Arguments:
 * 
 * 	tty	pointer to open tty structure
 * 	filp	pointer to open file object
 * 	
 * Return Value:	None
 */
static void mgsl_close(struct tty_struct *tty, struct file * filp)
{
	struct mgsl_struct * info = tty->driver_data;

	if (mgsl_paranoia_check(info, tty->name, "mgsl_close"))
		return;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_close(%s) entry, count=%d\n",
			 __FILE__,__LINE__, info->device_name, info->port.count);

	if (tty_port_close_start(&info->port, tty, filp) == 0)			 
		goto cleanup;
			
 	if (info->port.flags & ASYNC_INITIALIZED)
 		mgsl_wait_until_sent(tty, info->timeout);
	mgsl_flush_buffer(tty);
	tty_ldisc_flush(tty);
	shutdown(info);

	tty_port_close_end(&info->port, tty);	
	info->port.tty = NULL;
cleanup:			
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_close(%s) exit, count=%d\n", __FILE__,__LINE__,
			tty->driver->name, info->port.count);
			
}	/* end of mgsl_close() */

/* mgsl_wait_until_sent()
 *
 *	Wait until the transmitter is empty.
 *
 * Arguments:
 *
 *	tty		pointer to tty info structure
 *	timeout		time to wait for send completion
 *
 * Return Value:	None
 */
static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout)
{
	struct mgsl_struct * info = tty->driver_data;
	unsigned long orig_jiffies, char_time;

	if (!info )
		return;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_wait_until_sent(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );
      
	if (mgsl_paranoia_check(info, tty->name, "mgsl_wait_until_sent"))
		return;

	if (!(info->port.flags & ASYNC_INITIALIZED))
		goto exit;
	 
	orig_jiffies = jiffies;
      
	/* Set check interval to 1/5 of estimated time to
	 * send a character, and make it at least 1. The check
	 * interval should also be less than the timeout.
	 * Note: use tight timings here to satisfy the NIST-PCTS.
	 */ 

	lock_kernel();
	if ( info->params.data_rate ) {
	       	char_time = info->timeout/(32 * 5);
		if (!char_time)
			char_time++;
	} else
		char_time = 1;
		
	if (timeout)
		char_time = min_t(unsigned long, char_time, timeout);
		
	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		while (info->tx_active) {
			msleep_interruptible(jiffies_to_msecs(char_time));
			if (signal_pending(current))
				break;
			if (timeout && time_after(jiffies, orig_jiffies + timeout))
				break;
		}
	} else {
		while (!(usc_InReg(info,TCSR) & TXSTATUS_ALL_SENT) &&
			info->tx_enabled) {
			msleep_interruptible(jiffies_to_msecs(char_time));
			if (signal_pending(current))
				break;
			if (timeout && time_after(jiffies, orig_jiffies + timeout))
				break;
		}
	}
	unlock_kernel();
      
exit:
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_wait_until_sent(%s) exit\n",
			 __FILE__,__LINE__, info->device_name );
			 
}	/* end of mgsl_wait_until_sent() */

/* mgsl_hangup()
 *
 *	Called by tty_hangup() when a hangup is signaled.
 *	This is the same as to closing all open files for the port.
 *
 * Arguments:		tty	pointer to associated tty object
 * Return Value:	None
 */
static void mgsl_hangup(struct tty_struct *tty)
{
	struct mgsl_struct * info = tty->driver_data;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_hangup(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_hangup"))
		return;

	mgsl_flush_buffer(tty);
	shutdown(info);
	
	info->port.count = 0;	
	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
	info->port.tty = NULL;

	wake_up_interruptible(&info->port.open_wait);
	
}	/* end of mgsl_hangup() */

/*
 * carrier_raised()
 *
 *	Return true if carrier is raised
 */

static int carrier_raised(struct tty_port *port)
{
	unsigned long flags;
	struct mgsl_struct *info = container_of(port, struct mgsl_struct, port);
	
	spin_lock_irqsave(&info->irq_spinlock, flags);
 	usc_get_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock, flags);
	return (info->serial_signals & SerialSignal_DCD) ? 1 : 0;
}

static void dtr_rts(struct tty_port *port, int on)
{
	struct mgsl_struct *info = container_of(port, struct mgsl_struct, port);
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (on)
		info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
	else
		info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
 	usc_set_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}


/* block_til_ready()
 * 
 * 	Block the current process until the specified port
 * 	is ready to be opened.
 * 	
 * Arguments:
 * 
 * 	tty		pointer to tty info structure
 * 	filp		pointer to open file object
 * 	info		pointer to device instance data
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
			   struct mgsl_struct *info)
{
	DECLARE_WAITQUEUE(wait, current);
	int		retval;
	bool		do_clocal = false;
	bool		extra_count = false;
	unsigned long	flags;
	int		dcd;
	struct tty_port *port = &info->port;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):block_til_ready on %s\n",
			 __FILE__,__LINE__, tty->driver->name );

	if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
		/* nonblock mode is set or port is not enabled */
		port->flags |= ASYNC_NORMAL_ACTIVE;
		return 0;
	}

	if (tty->termios->c_cflag & CLOCAL)
		do_clocal = true;

	/* Wait for carrier detect and the line to become
	 * free (i.e., not in use by the callout).  While we are in
	 * this loop, port->count is dropped by one, so that
	 * mgsl_close() knows when to free things.  We restore it upon
	 * exit, either normal or abnormal.
	 */
	 
	retval = 0;
	add_wait_queue(&port->open_wait, &wait);
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):block_til_ready before block on %s count=%d\n",
			 __FILE__,__LINE__, tty->driver->name, port->count );

	spin_lock_irqsave(&info->irq_spinlock, flags);
	if (!tty_hung_up_p(filp)) {
		extra_count = true;
		port->count--;
	}
	spin_unlock_irqrestore(&info->irq_spinlock, flags);
	port->blocked_open++;
	
	while (1) {
		if (tty->termios->c_cflag & CBAUD)
			tty_port_raise_dtr_rts(port);
		
		set_current_state(TASK_INTERRUPTIBLE);
		
		if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)){
			retval = (port->flags & ASYNC_HUP_NOTIFY) ?
					-EAGAIN : -ERESTARTSYS;
			break;
		}
		
		dcd = tty_port_carrier_raised(&info->port);
		
 		if (!(port->flags & ASYNC_CLOSING) && (do_clocal || dcd))
 			break;
			
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
		
		if (debug_level >= DEBUG_LEVEL_INFO)
			printk("%s(%d):block_til_ready blocking on %s count=%d\n",
				 __FILE__,__LINE__, tty->driver->name, port->count );
				 
		schedule();
	}
	
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&port->open_wait, &wait);
	
	/* FIXME: Racy on hangup during close wait */
	if (extra_count)
		port->count++;
	port->blocked_open--;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):block_til_ready after blocking on %s count=%d\n",
			 __FILE__,__LINE__, tty->driver->name, port->count );
			 
	if (!retval)
		port->flags |= ASYNC_NORMAL_ACTIVE;
		
	return retval;
	
}	/* end of block_til_ready() */

/* mgsl_open()
 *
 *	Called when a port is opened.  Init and enable port.
 *	Perform serial-specific initialization for the tty structure.
 *
 * Arguments:		tty	pointer to tty info structure
 *			filp	associated file pointer
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_open(struct tty_struct *tty, struct file * filp)
{
	struct mgsl_struct	*info;
	int 			retval, line;
	unsigned long flags;

	/* verify range of specified line number */	
	line = tty->index;
	if ((line < 0) || (line >= mgsl_device_count)) {
		printk("%s(%d):mgsl_open with invalid line #%d.\n",
			__FILE__,__LINE__,line);
		return -ENODEV;
	}

	/* find the info structure for the specified line */
	info = mgsl_device_list;
	while(info && info->line != line)
		info = info->next_device;
	if (mgsl_paranoia_check(info, tty->name, "mgsl_open"))
		return -ENODEV;
	
	tty->driver_data = info;
	info->port.tty = tty;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_open(%s), old ref count = %d\n",
			 __FILE__,__LINE__,tty->driver->name, info->port.count);

	/* If port is closing, signal caller to try again */
	if (tty_hung_up_p(filp) || info->port.flags & ASYNC_CLOSING){
		if (info->port.flags & ASYNC_CLOSING)
			interruptible_sleep_on(&info->port.close_wait);
		retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
			-EAGAIN : -ERESTARTSYS);
		goto cleanup;
	}
	
	info->port.tty->low_latency = (info->port.flags & ASYNC_LOW_LATENCY) ? 1 : 0;

	spin_lock_irqsave(&info->netlock, flags);
	if (info->netcount) {
		retval = -EBUSY;
		spin_unlock_irqrestore(&info->netlock, flags);
		goto cleanup;
	}
	info->port.count++;
	spin_unlock_irqrestore(&info->netlock, flags);

	if (info->port.count == 1) {
		/* 1st open on this device, init hardware */
		retval = startup(info);
		if (retval < 0)
			goto cleanup;
	}

	retval = block_til_ready(tty, filp, info);
	if (retval) {
		if (debug_level >= DEBUG_LEVEL_INFO)
			printk("%s(%d):block_til_ready(%s) returned %d\n",
				 __FILE__,__LINE__, info->device_name, retval);
		goto cleanup;
	}

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_open(%s) success\n",
			 __FILE__,__LINE__, info->device_name);
	retval = 0;
	
cleanup:			
	if (retval) {
		if (tty->count == 1)
			info->port.tty = NULL; /* tty layer will release tty struct */
		if(info->port.count)
			info->port.count--;
	}
	
	return retval;
	
}	/* end of mgsl_open() */

/*
 * /proc fs routines....
 */

static inline void line_info(struct seq_file *m, struct mgsl_struct *info)
{
	char	stat_buf[30];
	unsigned long flags;

	if (info->bus_type == MGSL_BUS_TYPE_PCI) {
		seq_printf(m, "%s:PCI io:%04X irq:%d mem:%08X lcr:%08X",
			info->device_name, info->io_base, info->irq_level,
			info->phys_memory_base, info->phys_lcr_base);
	} else {
		seq_printf(m, "%s:(E)ISA io:%04X irq:%d dma:%d",
			info->device_name, info->io_base, 
			info->irq_level, info->dma_level);
	}

	/* output current serial signal states */
	spin_lock_irqsave(&info->irq_spinlock,flags);
 	usc_get_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
	stat_buf[0] = 0;
	stat_buf[1] = 0;
	if (info->serial_signals & SerialSignal_RTS)
		strcat(stat_buf, "|RTS");
	if (info->serial_signals & SerialSignal_CTS)
		strcat(stat_buf, "|CTS");
	if (info->serial_signals & SerialSignal_DTR)
		strcat(stat_buf, "|DTR");
	if (info->serial_signals & SerialSignal_DSR)
		strcat(stat_buf, "|DSR");
	if (info->serial_signals & SerialSignal_DCD)
		strcat(stat_buf, "|CD");
	if (info->serial_signals & SerialSignal_RI)
		strcat(stat_buf, "|RI");

	if (info->params.mode == MGSL_MODE_HDLC ||
	    info->params.mode == MGSL_MODE_RAW ) {
		seq_printf(m, " HDLC txok:%d rxok:%d",
			      info->icount.txok, info->icount.rxok);
		if (info->icount.txunder)
			seq_printf(m, " txunder:%d", info->icount.txunder);
		if (info->icount.txabort)
			seq_printf(m, " txabort:%d", info->icount.txabort);
		if (info->icount.rxshort)
			seq_printf(m, " rxshort:%d", info->icount.rxshort);
		if (info->icount.rxlong)
			seq_printf(m, " rxlong:%d", info->icount.rxlong);
		if (info->icount.rxover)
			seq_printf(m, " rxover:%d", info->icount.rxover);
		if (info->icount.rxcrc)
			seq_printf(m, " rxcrc:%d", info->icount.rxcrc);
	} else {
		seq_printf(m, " ASYNC tx:%d rx:%d",
			      info->icount.tx, info->icount.rx);
		if (info->icount.frame)
			seq_printf(m, " fe:%d", info->icount.frame);
		if (info->icount.parity)
			seq_printf(m, " pe:%d", info->icount.parity);
		if (info->icount.brk)
			seq_printf(m, " brk:%d", info->icount.brk);
		if (info->icount.overrun)
			seq_printf(m, " oe:%d", info->icount.overrun);
	}
	
	/* Append serial signal status to end */
	seq_printf(m, " %s\n", stat_buf+1);
	
	seq_printf(m, "txactive=%d bh_req=%d bh_run=%d pending_bh=%x\n",
	 info->tx_active,info->bh_requested,info->bh_running,
	 info->pending_bh);
	 
	spin_lock_irqsave(&info->irq_spinlock,flags);
	{	
	u16 Tcsr = usc_InReg( info, TCSR );
	u16 Tdmr = usc_InDmaReg( info, TDMR );
	u16 Ticr = usc_InReg( info, TICR );
	u16 Rscr = usc_InReg( info, RCSR );
	u16 Rdmr = usc_InDmaReg( info, RDMR );
	u16 Ricr = usc_InReg( info, RICR );
	u16 Icr = usc_InReg( info, ICR );
	u16 Dccr = usc_InReg( info, DCCR );
	u16 Tmr = usc_InReg( info, TMR );
	u16 Tccr = usc_InReg( info, TCCR );
	u16 Ccar = inw( info->io_base + CCAR );
	seq_printf(m, "tcsr=%04X tdmr=%04X ticr=%04X rcsr=%04X rdmr=%04X\n"
                        "ricr=%04X icr =%04X dccr=%04X tmr=%04X tccr=%04X ccar=%04X\n",
	 		Tcsr,Tdmr,Ticr,Rscr,Rdmr,Ricr,Icr,Dccr,Tmr,Tccr,Ccar );
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}

/* Called to print information about devices */
static int mgsl_proc_show(struct seq_file *m, void *v)
{
	struct mgsl_struct *info;
	
	seq_printf(m, "synclink driver:%s\n", driver_version);
	
	info = mgsl_device_list;
	while( info ) {
		line_info(m, info);
		info = info->next_device;
	}
	return 0;
}

static int mgsl_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, mgsl_proc_show, NULL);
}

static const struct file_operations mgsl_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= mgsl_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

/* mgsl_allocate_dma_buffers()
 * 
 * 	Allocate and format DMA buffers (ISA adapter)
 * 	or format shared memory buffers (PCI adapter).
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	0 if success, otherwise error
 */
static int mgsl_allocate_dma_buffers(struct mgsl_struct *info)
{
	unsigned short BuffersPerFrame;

	info->last_mem_alloc = 0;

	/* Calculate the number of DMA buffers necessary to hold the */
	/* largest allowable frame size. Note: If the max frame size is */
	/* not an even multiple of the DMA buffer size then we need to */
	/* round the buffer count per frame up one. */

	BuffersPerFrame = (unsigned short)(info->max_frame_size/DMABUFFERSIZE);
	if ( info->max_frame_size % DMABUFFERSIZE )
		BuffersPerFrame++;

	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		/*
		 * The PCI adapter has 256KBytes of shared memory to use.
		 * This is 64 PAGE_SIZE buffers.
		 *
		 * The first page is used for padding at this time so the
		 * buffer list does not begin at offset 0 of the PCI
		 * adapter's shared memory.
		 *
		 * The 2nd page is used for the buffer list. A 4K buffer
		 * list can hold 128 DMA_BUFFER structures at 32 bytes
		 * each.
		 *
		 * This leaves 62 4K pages.
		 *
		 * The next N pages are used for transmit frame(s). We
		 * reserve enough 4K page blocks to hold the required
		 * number of transmit dma buffers (num_tx_dma_buffers),
		 * each of MaxFrameSize size.
		 *
		 * Of the remaining pages (62-N), determine how many can
		 * be used to receive full MaxFrameSize inbound frames
		 */
		info->tx_buffer_count = info->num_tx_dma_buffers * BuffersPerFrame;
		info->rx_buffer_count = 62 - info->tx_buffer_count;
	} else {
		/* Calculate the number of PAGE_SIZE buffers needed for */
		/* receive and transmit DMA buffers. */


		/* Calculate the number of DMA buffers necessary to */
		/* hold 7 max size receive frames and one max size transmit frame. */
		/* The receive buffer count is bumped by one so we avoid an */
		/* End of List condition if all receive buffers are used when */
		/* using linked list DMA buffers. */

		info->tx_buffer_count = info->num_tx_dma_buffers * BuffersPerFrame;
		info->rx_buffer_count = (BuffersPerFrame * MAXRXFRAMES) + 6;
		
		/* 
		 * limit total TxBuffers & RxBuffers to 62 4K total 
		 * (ala PCI Allocation) 
		 */
		
		if ( (info->tx_buffer_count + info->rx_buffer_count) > 62 )
			info->rx_buffer_count = 62 - info->tx_buffer_count;

	}

	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("%s(%d):Allocating %d TX and %d RX DMA buffers.\n",
			__FILE__,__LINE__, info->tx_buffer_count,info->rx_buffer_count);
	
	if ( mgsl_alloc_buffer_list_memory( info ) < 0 ||
		  mgsl_alloc_frame_memory(info, info->rx_buffer_list, info->rx_buffer_count) < 0 || 
		  mgsl_alloc_frame_memory(info, info->tx_buffer_list, info->tx_buffer_count) < 0 || 
		  mgsl_alloc_intermediate_rxbuffer_memory(info) < 0  ||
		  mgsl_alloc_intermediate_txbuffer_memory(info) < 0 ) {
		printk("%s(%d):Can't allocate DMA buffer memory\n",__FILE__,__LINE__);
		return -ENOMEM;
	}
	
	mgsl_reset_rx_dma_buffers( info );
  	mgsl_reset_tx_dma_buffers( info );

	return 0;

}	/* end of mgsl_allocate_dma_buffers() */

/*
 * mgsl_alloc_buffer_list_memory()
 * 
 * Allocate a common DMA buffer for use as the
 * receive and transmit buffer lists.
 * 
 * A buffer list is a set of buffer entries where each entry contains
 * a pointer to an actual buffer and a pointer to the next buffer entry
 * (plus some other info about the buffer).
 * 
 * The buffer entries for a list are built to form a circular list so
 * that when the entire list has been traversed you start back at the
 * beginning.
 * 
 * This function allocates memory for just the buffer entries.
 * The links (pointer to next entry) are filled in with the physical
 * address of the next entry so the adapter can navigate the list
 * using bus master DMA. The pointers to the actual buffers are filled
 * out later when the actual buffers are allocated.
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	0 if success, otherwise error
 */
static int mgsl_alloc_buffer_list_memory( struct mgsl_struct *info )
{
	unsigned int i;

	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		/* PCI adapter uses shared memory. */
		info->buffer_list = info->memory_base + info->last_mem_alloc;
		info->buffer_list_phys = info->last_mem_alloc;
		info->last_mem_alloc += BUFFERLISTSIZE;
	} else {
		/* ISA adapter uses system memory. */
		/* The buffer lists are allocated as a common buffer that both */
		/* the processor and adapter can access. This allows the driver to */
		/* inspect portions of the buffer while other portions are being */
		/* updated by the adapter using Bus Master DMA. */

		info->buffer_list = dma_alloc_coherent(NULL, BUFFERLISTSIZE, &info->buffer_list_dma_addr, GFP_KERNEL);
		if (info->buffer_list == NULL)
			return -ENOMEM;
		info->buffer_list_phys = (u32)(info->buffer_list_dma_addr);
	}

	/* We got the memory for the buffer entry lists. */
	/* Initialize the memory block to all zeros. */
	memset( info->buffer_list, 0, BUFFERLISTSIZE );

	/* Save virtual address pointers to the receive and */
	/* transmit buffer lists. (Receive 1st). These pointers will */
	/* be used by the processor to access the lists. */
	info->rx_buffer_list = (DMABUFFERENTRY *)info->buffer_list;
	info->tx_buffer_list = (DMABUFFERENTRY *)info->buffer_list;
	info->tx_buffer_list += info->rx_buffer_count;

	/*
	 * Build the links for the buffer entry lists such that
	 * two circular lists are built. (Transmit and Receive).
	 *
	 * Note: the links are physical addresses
	 * which are read by the adapter to determine the next
	 * buffer entry to use.
	 */

	for ( i = 0; i < info->rx_buffer_count; i++ ) {
		/* calculate and store physical address of this buffer entry */
		info->rx_buffer_list[i].phys_entry =
			info->buffer_list_phys + (i * sizeof(DMABUFFERENTRY));

		/* calculate and store physical address of */
		/* next entry in cirular list of entries */

		info->rx_buffer_list[i].link = info->buffer_list_phys;

		if ( i < info->rx_buffer_count - 1 )
			info->rx_buffer_list[i].link += (i + 1) * sizeof(DMABUFFERENTRY);
	}

	for ( i = 0; i < info->tx_buffer_count; i++ ) {
		/* calculate and store physical address of this buffer entry */
		info->tx_buffer_list[i].phys_entry = info->buffer_list_phys +
			((info->rx_buffer_count + i) * sizeof(DMABUFFERENTRY));

		/* calculate and store physical address of */
		/* next entry in cirular list of entries */

		info->tx_buffer_list[i].link = info->buffer_list_phys +
			info->rx_buffer_count * sizeof(DMABUFFERENTRY);

		if ( i < info->tx_buffer_count - 1 )
			info->tx_buffer_list[i].link += (i + 1) * sizeof(DMABUFFERENTRY);
	}

	return 0;

}	/* end of mgsl_alloc_buffer_list_memory() */

/* Free DMA buffers allocated for use as the
 * receive and transmit buffer lists.
 * Warning:
 * 
 * 	The data transfer buffers associated with the buffer list
 * 	MUST be freed before freeing the buffer list itself because
 * 	the buffer list contains the information necessary to free
 * 	the individual buffers!
 */
static void mgsl_free_buffer_list_memory( struct mgsl_struct *info )
{
	if (info->buffer_list && info->bus_type != MGSL_BUS_TYPE_PCI)
		dma_free_coherent(NULL, BUFFERLISTSIZE, info->buffer_list, info->buffer_list_dma_addr);
		
	info->buffer_list = NULL;
	info->rx_buffer_list = NULL;
	info->tx_buffer_list = NULL;

}	/* end of mgsl_free_buffer_list_memory() */

/*
 * mgsl_alloc_frame_memory()
 * 
 * 	Allocate the frame DMA buffers used by the specified buffer list.
 * 	Each DMA buffer will be one memory page in size. This is necessary
 * 	because memory can fragment enough that it may be impossible
 * 	contiguous pages.
 * 
 * Arguments:
 * 
 *	info		pointer to device instance data
 * 	BufferList	pointer to list of buffer entries
 * 	Buffercount	count of buffer entries in buffer list
 * 
 * Return Value:	0 if success, otherwise -ENOMEM
 */
static int mgsl_alloc_frame_memory(struct mgsl_struct *info,DMABUFFERENTRY *BufferList,int Buffercount)
{
	int i;
	u32 phys_addr;

	/* Allocate page sized buffers for the receive buffer list */

	for ( i = 0; i < Buffercount; i++ ) {
		if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
			/* PCI adapter uses shared memory buffers. */
			BufferList[i].virt_addr = info->memory_base + info->last_mem_alloc;
			phys_addr = info->last_mem_alloc;
			info->last_mem_alloc += DMABUFFERSIZE;
		} else {
			/* ISA adapter uses system memory. */
			BufferList[i].virt_addr = dma_alloc_coherent(NULL, DMABUFFERSIZE, &BufferList[i].dma_addr, GFP_KERNEL);
			if (BufferList[i].virt_addr == NULL)
				return -ENOMEM;
			phys_addr = (u32)(BufferList[i].dma_addr);
		}
		BufferList[i].phys_addr = phys_addr;
	}

	return 0;

}	/* end of mgsl_alloc_frame_memory() */

/*
 * mgsl_free_frame_memory()
 * 
 * 	Free the buffers associated with
 * 	each buffer entry of a buffer list.
 * 
 * Arguments:
 * 
 *	info		pointer to device instance data
 * 	BufferList	pointer to list of buffer entries
 * 	Buffercount	count of buffer entries in buffer list
 * 
 * Return Value:	None
 */
static void mgsl_free_frame_memory(struct mgsl_struct *info, DMABUFFERENTRY *BufferList, int Buffercount)
{
	int i;

	if ( BufferList ) {
		for ( i = 0 ; i < Buffercount ; i++ ) {
			if ( BufferList[i].virt_addr ) {
				if ( info->bus_type != MGSL_BUS_TYPE_PCI )
					dma_free_coherent(NULL, DMABUFFERSIZE, BufferList[i].virt_addr, BufferList[i].dma_addr);
				BufferList[i].virt_addr = NULL;
			}
		}
	}

}	/* end of mgsl_free_frame_memory() */

/* mgsl_free_dma_buffers()
 * 
 * 	Free DMA buffers
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_free_dma_buffers( struct mgsl_struct *info )
{
	mgsl_free_frame_memory( info, info->rx_buffer_list, info->rx_buffer_count );
	mgsl_free_frame_memory( info, info->tx_buffer_list, info->tx_buffer_count );
	mgsl_free_buffer_list_memory( info );

}	/* end of mgsl_free_dma_buffers() */


/*
 * mgsl_alloc_intermediate_rxbuffer_memory()
 * 
 * 	Allocate a buffer large enough to hold max_frame_size. This buffer
 *	is used to pass an assembled frame to the line discipline.
 * 
 * Arguments:
 * 
 *	info		pointer to device instance data
 * 
 * Return Value:	0 if success, otherwise -ENOMEM
 */
static int mgsl_alloc_intermediate_rxbuffer_memory(struct mgsl_struct *info)
{
	info->intermediate_rxbuffer = kmalloc(info->max_frame_size, GFP_KERNEL | GFP_DMA);
	if ( info->intermediate_rxbuffer == NULL )
		return -ENOMEM;

	return 0;

}	/* end of mgsl_alloc_intermediate_rxbuffer_memory() */

/*
 * mgsl_free_intermediate_rxbuffer_memory()
 * 
 * 
 * Arguments:
 * 
 *	info		pointer to device instance data
 * 
 * Return Value:	None
 */
static void mgsl_free_intermediate_rxbuffer_memory(struct mgsl_struct *info)
{
	kfree(info->intermediate_rxbuffer);
	info->intermediate_rxbuffer = NULL;

}	/* end of mgsl_free_intermediate_rxbuffer_memory() */

/*
 * mgsl_alloc_intermediate_txbuffer_memory()
 *
 * 	Allocate intermdiate transmit buffer(s) large enough to hold max_frame_size.
 * 	This buffer is used to load transmit frames into the adapter's dma transfer
 * 	buffers when there is sufficient space.
 *
 * Arguments:
 *
 *	info		pointer to device instance data
 *
 * Return Value:	0 if success, otherwise -ENOMEM
 */
static int mgsl_alloc_intermediate_txbuffer_memory(struct mgsl_struct *info)
{
	int i;

	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("%s %s(%d)  allocating %d tx holding buffers\n",
				info->device_name, __FILE__,__LINE__,info->num_tx_holding_buffers);

	memset(info->tx_holding_buffers,0,sizeof(info->tx_holding_buffers));

	for ( i=0; i<info->num_tx_holding_buffers; ++i) {
		info->tx_holding_buffers[i].buffer =
			kmalloc(info->max_frame_size, GFP_KERNEL);
		if (info->tx_holding_buffers[i].buffer == NULL) {
			for (--i; i >= 0; i--) {
				kfree(info->tx_holding_buffers[i].buffer);
				info->tx_holding_buffers[i].buffer = NULL;
			}
			return -ENOMEM;
		}
	}

	return 0;

}	/* end of mgsl_alloc_intermediate_txbuffer_memory() */

/*
 * mgsl_free_intermediate_txbuffer_memory()
 *
 *
 * Arguments:
 *
 *	info		pointer to device instance data
 *
 * Return Value:	None
 */
static void mgsl_free_intermediate_txbuffer_memory(struct mgsl_struct *info)
{
	int i;

	for ( i=0; i<info->num_tx_holding_buffers; ++i ) {
		kfree(info->tx_holding_buffers[i].buffer);
		info->tx_holding_buffers[i].buffer = NULL;
	}

	info->get_tx_holding_index = 0;
	info->put_tx_holding_index = 0;
	info->tx_holding_count = 0;

}	/* end of mgsl_free_intermediate_txbuffer_memory() */


/*
 * load_next_tx_holding_buffer()
 *
 * attempts to load the next buffered tx request into the
 * tx dma buffers
 *
 * Arguments:
 *
 *	info		pointer to device instance data
 *
 * Return Value:	true if next buffered tx request loaded
 * 			into adapter's tx dma buffer,
 * 			false otherwise
 */
static bool load_next_tx_holding_buffer(struct mgsl_struct *info)
{
	bool ret = false;

	if ( info->tx_holding_count ) {
		/* determine if we have enough tx dma buffers
		 * to accommodate the next tx frame
		 */
		struct tx_holding_buffer *ptx =
			&info->tx_holding_buffers[info->get_tx_holding_index];
		int num_free = num_free_tx_dma_buffers(info);
		int num_needed = ptx->buffer_size / DMABUFFERSIZE;
		if ( ptx->buffer_size % DMABUFFERSIZE )
			++num_needed;

		if (num_needed <= num_free) {
			info->xmit_cnt = ptx->buffer_size;
			mgsl_load_tx_dma_buffer(info,ptx->buffer,ptx->buffer_size);

			--info->tx_holding_count;
			if ( ++info->get_tx_holding_index >= info->num_tx_holding_buffers)
				info->get_tx_holding_index=0;

			/* restart transmit timer */
			mod_timer(&info->tx_timer, jiffies + msecs_to_jiffies(5000));

			ret = true;
		}
	}

	return ret;
}

/*
 * save_tx_buffer_request()
 *
 * attempt to store transmit frame request for later transmission
 *
 * Arguments:
 *
 *	info		pointer to device instance data
 * 	Buffer		pointer to buffer containing frame to load
 * 	BufferSize	size in bytes of frame in Buffer
 *
 * Return Value:	1 if able to store, 0 otherwise
 */
static int save_tx_buffer_request(struct mgsl_struct *info,const char *Buffer, unsigned int BufferSize)
{
	struct tx_holding_buffer *ptx;

	if ( info->tx_holding_count >= info->num_tx_holding_buffers ) {
		return 0;	        /* all buffers in use */
	}

	ptx = &info->tx_holding_buffers[info->put_tx_holding_index];
	ptx->buffer_size = BufferSize;
	memcpy( ptx->buffer, Buffer, BufferSize);

	++info->tx_holding_count;
	if ( ++info->put_tx_holding_index >= info->num_tx_holding_buffers)
		info->put_tx_holding_index=0;

	return 1;
}

static int mgsl_claim_resources(struct mgsl_struct *info)
{
	if (request_region(info->io_base,info->io_addr_size,"synclink") == NULL) {
		printk( "%s(%d):I/O address conflict on device %s Addr=%08X\n",
			__FILE__,__LINE__,info->device_name, info->io_base);
		return -ENODEV;
	}
	info->io_addr_requested = true;
	
	if ( request_irq(info->irq_level,mgsl_interrupt,info->irq_flags,
		info->device_name, info ) < 0 ) {
		printk( "%s(%d):Cant request interrupt on device %s IRQ=%d\n",
			__FILE__,__LINE__,info->device_name, info->irq_level );
		goto errout;
	}
	info->irq_requested = true;
	
	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		if (request_mem_region(info->phys_memory_base,0x40000,"synclink") == NULL) {
			printk( "%s(%d):mem addr conflict device %s Addr=%08X\n",
				__FILE__,__LINE__,info->device_name, info->phys_memory_base);
			goto errout;
		}
		info->shared_mem_requested = true;
		if (request_mem_region(info->phys_lcr_base + info->lcr_offset,128,"synclink") == NULL) {
			printk( "%s(%d):lcr mem addr conflict device %s Addr=%08X\n",
				__FILE__,__LINE__,info->device_name, info->phys_lcr_base + info->lcr_offset);
			goto errout;
		}
		info->lcr_mem_requested = true;

		info->memory_base = ioremap_nocache(info->phys_memory_base,
								0x40000);
		if (!info->memory_base) {
			printk( "%s(%d):Cant map shared memory on device %s MemAddr=%08X\n",
				__FILE__,__LINE__,info->device_name, info->phys_memory_base );
			goto errout;
		}
		
		if ( !mgsl_memory_test(info) ) {
			printk( "%s(%d):Failed shared memory test %s MemAddr=%08X\n",
				__FILE__,__LINE__,info->device_name, info->phys_memory_base );
			goto errout;
		}
		
		info->lcr_base = ioremap_nocache(info->phys_lcr_base,
								PAGE_SIZE);
		if (!info->lcr_base) {
			printk( "%s(%d):Cant map LCR memory on device %s MemAddr=%08X\n",
				__FILE__,__LINE__,info->device_name, info->phys_lcr_base );
			goto errout;
		}
		info->lcr_base += info->lcr_offset;
		
	} else {
		/* claim DMA channel */
		
		if (request_dma(info->dma_level,info->device_name) < 0){
			printk( "%s(%d):Cant request DMA channel on device %s DMA=%d\n",
				__FILE__,__LINE__,info->device_name, info->dma_level );
			mgsl_release_resources( info );
			return -ENODEV;
		}
		info->dma_requested = true;

		/* ISA adapter uses bus master DMA */		
		set_dma_mode(info->dma_level,DMA_MODE_CASCADE);
		enable_dma(info->dma_level);
	}
	
	if ( mgsl_allocate_dma_buffers(info) < 0 ) {
		printk( "%s(%d):Cant allocate DMA buffers on device %s DMA=%d\n",
			__FILE__,__LINE__,info->device_name, info->dma_level );
		goto errout;
	}	
	
	return 0;
errout:
	mgsl_release_resources(info);
	return -ENODEV;

}	/* end of mgsl_claim_resources() */

static void mgsl_release_resources(struct mgsl_struct *info)
{
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_release_resources(%s) entry\n",
			__FILE__,__LINE__,info->device_name );
			
	if ( info->irq_requested ) {
		free_irq(info->irq_level, info);
		info->irq_requested = false;
	}
	if ( info->dma_requested ) {
		disable_dma(info->dma_level);
		free_dma(info->dma_level);
		info->dma_requested = false;
	}
	mgsl_free_dma_buffers(info);
	mgsl_free_intermediate_rxbuffer_memory(info);
     	mgsl_free_intermediate_txbuffer_memory(info);
	
	if ( info->io_addr_requested ) {
		release_region(info->io_base,info->io_addr_size);
		info->io_addr_requested = false;
	}
	if ( info->shared_mem_requested ) {
		release_mem_region(info->phys_memory_base,0x40000);
		info->shared_mem_requested = false;
	}
	if ( info->lcr_mem_requested ) {
		release_mem_region(info->phys_lcr_base + info->lcr_offset,128);
		info->lcr_mem_requested = false;
	}
	if (info->memory_base){
		iounmap(info->memory_base);
		info->memory_base = NULL;
	}
	if (info->lcr_base){
		iounmap(info->lcr_base - info->lcr_offset);
		info->lcr_base = NULL;
	}
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_release_resources(%s) exit\n",
			__FILE__,__LINE__,info->device_name );
			
}	/* end of mgsl_release_resources() */

/* mgsl_add_device()
 * 
 * 	Add the specified device instance data structure to the
 * 	global linked list of devices and increment the device count.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_add_device( struct mgsl_struct *info )
{
	info->next_device = NULL;
	info->line = mgsl_device_count;
	sprintf(info->device_name,"ttySL%d",info->line);
	
	if (info->line < MAX_TOTAL_DEVICES) {
		if (maxframe[info->line])
			info->max_frame_size = maxframe[info->line];

		if (txdmabufs[info->line]) {
			info->num_tx_dma_buffers = txdmabufs[info->line];
			if (info->num_tx_dma_buffers < 1)
				info->num_tx_dma_buffers = 1;
		}

		if (txholdbufs[info->line]) {
			info->num_tx_holding_buffers = txholdbufs[info->line];
			if (info->num_tx_holding_buffers < 1)
				info->num_tx_holding_buffers = 1;
			else if (info->num_tx_holding_buffers > MAX_TX_HOLDING_BUFFERS)
				info->num_tx_holding_buffers = MAX_TX_HOLDING_BUFFERS;
		}
	}

	mgsl_device_count++;
	
	if ( !mgsl_device_list )
		mgsl_device_list = info;
	else {	
		struct mgsl_struct *current_dev = mgsl_device_list;
		while( current_dev->next_device )
			current_dev = current_dev->next_device;
		current_dev->next_device = info;
	}
	
	if ( info->max_frame_size < 4096 )
		info->max_frame_size = 4096;
	else if ( info->max_frame_size > 65535 )
		info->max_frame_size = 65535;
	
	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		printk( "SyncLink PCI v%d %s: IO=%04X IRQ=%d Mem=%08X,%08X MaxFrameSize=%u\n",
			info->hw_version + 1, info->device_name, info->io_base, info->irq_level,
			info->phys_memory_base, info->phys_lcr_base,
		     	info->max_frame_size );
	} else {
		printk( "SyncLink ISA %s: IO=%04X IRQ=%d DMA=%d MaxFrameSize=%u\n",
			info->device_name, info->io_base, info->irq_level, info->dma_level,
		     	info->max_frame_size );
	}

#if SYNCLINK_GENERIC_HDLC
	hdlcdev_init(info);
#endif

}	/* end of mgsl_add_device() */

static const struct tty_port_operations mgsl_port_ops = {
	.carrier_raised = carrier_raised,
	.dtr_rts = dtr_rts,
};


/* mgsl_allocate_device()
 * 
 * 	Allocate and initialize a device instance structure
 * 	
 * Arguments:		none
 * Return Value:	pointer to mgsl_struct if success, otherwise NULL
 */
static struct mgsl_struct* mgsl_allocate_device(void)
{
	struct mgsl_struct *info;
	
	info = kzalloc(sizeof(struct mgsl_struct),
		 GFP_KERNEL);
		 
	if (!info) {
		printk("Error can't allocate device instance data\n");
	} else {
		tty_port_init(&info->port);
		info->port.ops = &mgsl_port_ops;
		info->magic = MGSL_MAGIC;
		INIT_WORK(&info->task, mgsl_bh_handler);
		info->max_frame_size = 4096;
		info->port.close_delay = 5*HZ/10;
		info->port.closing_wait = 30*HZ;
		init_waitqueue_head(&info->status_event_wait_q);
		init_waitqueue_head(&info->event_wait_q);
		spin_lock_init(&info->irq_spinlock);
		spin_lock_init(&info->netlock);
		memcpy(&info->params,&default_params,sizeof(MGSL_PARAMS));
		info->idle_mode = HDLC_TXIDLE_FLAGS;		
		info->num_tx_dma_buffers = 1;
		info->num_tx_holding_buffers = 0;
	}
	
	return info;

}	/* end of mgsl_allocate_device()*/

static const struct tty_operations mgsl_ops = {
	.open = mgsl_open,
	.close = mgsl_close,
	.write = mgsl_write,
	.put_char = mgsl_put_char,
	.flush_chars = mgsl_flush_chars,
	.write_room = mgsl_write_room,
	.chars_in_buffer = mgsl_chars_in_buffer,
	.flush_buffer = mgsl_flush_buffer,
	.ioctl = mgsl_ioctl,
	.throttle = mgsl_throttle,
	.unthrottle = mgsl_unthrottle,
	.send_xchar = mgsl_send_xchar,
	.break_ctl = mgsl_break,
	.wait_until_sent = mgsl_wait_until_sent,
	.set_termios = mgsl_set_termios,
	.stop = mgsl_stop,
	.start = mgsl_start,
	.hangup = mgsl_hangup,
	.tiocmget = tiocmget,
	.tiocmset = tiocmset,
	.proc_fops = &mgsl_proc_fops,
};

/*
 * perform tty device initialization
 */
static int mgsl_init_tty(void)
{
	int rc;

	serial_driver = alloc_tty_driver(128);
	if (!serial_driver)
		return -ENOMEM;
	
	serial_driver->owner = THIS_MODULE;
	serial_driver->driver_name = "synclink";
	serial_driver->name = "ttySL";
	serial_driver->major = ttymajor;
	serial_driver->minor_start = 64;
	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
	serial_driver->subtype = SERIAL_TYPE_NORMAL;
	serial_driver->init_termios = tty_std_termios;
	serial_driver->init_termios.c_cflag =
		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	serial_driver->init_termios.c_ispeed = 9600;
	serial_driver->init_termios.c_ospeed = 9600;
	serial_driver->flags = TTY_DRIVER_REAL_RAW;
	tty_set_operations(serial_driver, &mgsl_ops);
	if ((rc = tty_register_driver(serial_driver)) < 0) {
		printk("%s(%d):Couldn't register serial driver\n",
			__FILE__,__LINE__);
		put_tty_driver(serial_driver);
		serial_driver = NULL;
		return rc;
	}
			
 	printk("%s %s, tty major#%d\n",
		driver_name, driver_version,
		serial_driver->major);
	return 0;
}

/* enumerate user specified ISA adapters
 */
static void mgsl_enum_isa_devices(void)
{
	struct mgsl_struct *info;
	int i;
		
	/* Check for user specified ISA devices */
	
	for (i=0 ;(i < MAX_ISA_DEVICES) && io[i] && irq[i]; i++){
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk("ISA device specified io=%04X,irq=%d,dma=%d\n",
				io[i], irq[i], dma[i] );
		
		info = mgsl_allocate_device();
		if ( !info ) {
			/* error allocating device instance data */
			if ( debug_level >= DEBUG_LEVEL_ERROR )
				printk( "can't allocate device instance data.\n");
			continue;
		}
		
		/* Copy user configuration info to device instance data */
		info->io_base = (unsigned int)io[i];
		info->irq_level = (unsigned int)irq[i];
		info->irq_level = irq_canonicalize(info->irq_level);
		info->dma_level = (unsigned int)dma[i];
		info->bus_type = MGSL_BUS_TYPE_ISA;
		info->io_addr_size = 16;
		info->irq_flags = 0;
		
		mgsl_add_device( info );
	}
}

static void synclink_cleanup(void)
{
	int rc;
	struct mgsl_struct *info;
	struct mgsl_struct *tmp;

	printk("Unloading %s: %s\n", driver_name, driver_version);

	if (serial_driver) {
		if ((rc = tty_unregister_driver(serial_driver)))
			printk("%s(%d) failed to unregister tty driver err=%d\n",
			       __FILE__,__LINE__,rc);
		put_tty_driver(serial_driver);
	}

	info = mgsl_device_list;
	while(info) {
#if SYNCLINK_GENERIC_HDLC
		hdlcdev_exit(info);
#endif
		mgsl_release_resources(info);
		tmp = info;
		info = info->next_device;
		kfree(tmp);
	}
	
	if (pci_registered)
		pci_unregister_driver(&synclink_pci_driver);
}

static int __init synclink_init(void)
{
	int rc;

	if (break_on_load) {
	 	mgsl_get_text_ptr();
  		BREAKPOINT();
	}

 	printk("%s %s\n", driver_name, driver_version);

	mgsl_enum_isa_devices();
	if ((rc = pci_register_driver(&synclink_pci_driver)) < 0)
		printk("%s:failed to register PCI driver, error=%d\n",__FILE__,rc);
	else
		pci_registered = true;

	if ((rc = mgsl_init_tty()) < 0)
		goto error;

	return 0;

error:
	synclink_cleanup();
	return rc;
}

static void __exit synclink_exit(void)
{
	synclink_cleanup();
}

module_init(synclink_init);
module_exit(synclink_exit);

/*
 * usc_RTCmd()
 *
 * Issue a USC Receive/Transmit command to the
 * Channel Command/Address Register (CCAR).
 *
 * Notes:
 *
 *    The command is encoded in the most significant 5 bits <15..11>
 *    of the CCAR value. Bits <10..7> of the CCAR must be preserved
 *    and Bits <6..0> must be written as zeros.
 *
 * Arguments:
 *
 *    info   pointer to device information structure
 *    Cmd    command mask (use symbolic macros)
 *
 * Return Value:
 *
 *    None
 */
static void usc_RTCmd( struct mgsl_struct *info, u16 Cmd )
{
	/* output command to CCAR in bits <15..11> */
	/* preserve bits <10..7>, bits <6..0> must be zero */

	outw( Cmd + info->loopback_bits, info->io_base + CCAR );

	/* Read to flush write to CCAR */
	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		inw( info->io_base + CCAR );

}	/* end of usc_RTCmd() */

/*
 * usc_DmaCmd()
 *
 *    Issue a DMA command to the DMA Command/Address Register (DCAR).
 *
 * Arguments:
 *
 *    info   pointer to device information structure
 *    Cmd    DMA command mask (usc_DmaCmd_XX Macros)
 *
 * Return Value:
 *
 *       None
 */
static void usc_DmaCmd( struct mgsl_struct *info, u16 Cmd )
{
	/* write command mask to DCAR */
	outw( Cmd + info->mbre_bit, info->io_base );

	/* Read to flush write to DCAR */
	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		inw( info->io_base );

}	/* end of usc_DmaCmd() */

/*
 * usc_OutDmaReg()
 *
 *    Write a 16-bit value to a USC DMA register
 *
 * Arguments:
 *
 *    info      pointer to device info structure
 *    RegAddr   register address (number) for write
 *    RegValue  16-bit value to write to register
 *
 * Return Value:
 *
 *    None
 *
 */
static void usc_OutDmaReg( struct mgsl_struct *info, u16 RegAddr, u16 RegValue )
{
	/* Note: The DCAR is located at the adapter base address */
	/* Note: must preserve state of BIT8 in DCAR */

	outw( RegAddr + info->mbre_bit, info->io_base );
	outw( RegValue, info->io_base );

	/* Read to flush write to DCAR */
	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		inw( info->io_base );

}	/* end of usc_OutDmaReg() */
 
/*
 * usc_InDmaReg()
 *
 *    Read a 16-bit value from a DMA register
 *
 * Arguments:
 *
 *    info     pointer to device info structure
 *    RegAddr  register address (number) to read from
 *
 * Return Value:
 *
 *    The 16-bit value read from register
 *
 */
static u16 usc_InDmaReg( struct mgsl_struct *info, u16 RegAddr )
{
	/* Note: The DCAR is located at the adapter base address */
	/* Note: must preserve state of BIT8 in DCAR */

	outw( RegAddr + info->mbre_bit, info->io_base );
	return inw( info->io_base );

}	/* end of usc_InDmaReg() */

/*
 *
 * usc_OutReg()
 *
 *    Write a 16-bit value to a USC serial channel register 
 *
 * Arguments:
 *
 *    info      pointer to device info structure
 *    RegAddr   register address (number) to write to
 *    RegValue  16-bit value to write to register
 *
 * Return Value:
 *
 *    None
 *
 */
static void usc_OutReg( struct mgsl_struct *info, u16 RegAddr, u16 RegValue )
{
	outw( RegAddr + info->loopback_bits, info->io_base + CCAR );
	outw( RegValue, info->io_base + CCAR );

	/* Read to flush write to CCAR */
	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		inw( info->io_base + CCAR );

}	/* end of usc_OutReg() */

/*
 * usc_InReg()
 *
 *    Reads a 16-bit value from a USC serial channel register
 *
 * Arguments:
 *
 *    info       pointer to device extension
 *    RegAddr    register address (number) to read from
 *
 * Return Value:
 *
 *    16-bit value read from register
 */
static u16 usc_InReg( struct mgsl_struct *info, u16 RegAddr )
{
	outw( RegAddr + info->loopback_bits, info->io_base + CCAR );
	return inw( info->io_base + CCAR );

}	/* end of usc_InReg() */

/* usc_set_sdlc_mode()
 *
 *    Set up the adapter for SDLC DMA communications.
 *
 * Arguments:		info    pointer to device instance data
 * Return Value: 	NONE
 */
static void usc_set_sdlc_mode( struct mgsl_struct *info )
{
	u16 RegValue;
	bool PreSL1660;
	
	/*
	 * determine if the IUSC on the adapter is pre-SL1660. If
	 * not, take advantage of the UnderWait feature of more
	 * modern chips. If an underrun occurs and this bit is set,
	 * the transmitter will idle the programmed idle pattern
	 * until the driver has time to service the underrun. Otherwise,
	 * the dma controller may get the cycles previously requested
	 * and begin transmitting queued tx data.
	 */
	usc_OutReg(info,TMCR,0x1f);
	RegValue=usc_InReg(info,TMDR);
	PreSL1660 = (RegValue == IUSC_PRE_SL1660);

 	if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
 	{
 	   /*
 	   ** Channel Mode Register (CMR)
 	   **
 	   ** <15..14>    10    Tx Sub Modes, Send Flag on Underrun
 	   ** <13>        0     0 = Transmit Disabled (initially)
 	   ** <12>        0     1 = Consecutive Idles share common 0
 	   ** <11..8>     1110  Transmitter Mode = HDLC/SDLC Loop
 	   ** <7..4>      0000  Rx Sub Modes, addr/ctrl field handling
 	   ** <3..0>      0110  Receiver Mode = HDLC/SDLC
 	   **
 	   ** 1000 1110 0000 0110 = 0x8e06
 	   */
 	   RegValue = 0x8e06;
 
 	   /*--------------------------------------------------
 	    * ignore user options for UnderRun Actions and
 	    * preambles
 	    *--------------------------------------------------*/
 	}
 	else
 	{	
		/* Channel mode Register (CMR)
		 *
		 * <15..14>  00    Tx Sub modes, Underrun Action
		 * <13>      0     1 = Send Preamble before opening flag
		 * <12>      0     1 = Consecutive Idles share common 0
		 * <11..8>   0110  Transmitter mode = HDLC/SDLC
		 * <7..4>    0000  Rx Sub modes, addr/ctrl field handling
		 * <3..0>    0110  Receiver mode = HDLC/SDLC
		 *
		 * 0000 0110 0000 0110 = 0x0606
		 */
		if (info->params.mode == MGSL_MODE_RAW) {
			RegValue = 0x0001;		/* Set Receive mode = external sync */

			usc_OutReg( info, IOCR,		/* Set IOCR DCD is RxSync Detect Input */
				(unsigned short)((usc_InReg(info, IOCR) & ~(BIT13|BIT12)) | BIT12));

			/*
			 * TxSubMode:
			 * 	CMR <15>		0	Don't send CRC on Tx Underrun
			 * 	CMR <14>		x	undefined
			 * 	CMR <13>		0	Send preamble before openning sync
			 * 	CMR <12>		0	Send 8-bit syncs, 1=send Syncs per TxLength
			 *
			 * TxMode:
			 * 	CMR <11-8)	0100	MonoSync
			 *
			 * 	0x00 0100 xxxx xxxx  04xx
			 */
			RegValue |= 0x0400;
		}
		else {

		RegValue = 0x0606;

		if ( info->params.flags & HDLC_FLAG_UNDERRUN_ABORT15 )
			RegValue |= BIT14;
		else if ( info->params.flags & HDLC_FLAG_UNDERRUN_FLAG )
			RegValue |= BIT15;
		else if ( info->params.flags & HDLC_FLAG_UNDERRUN_CRC )
			RegValue |= BIT15 + BIT14;
		}

		if ( info->params.preamble != HDLC_PREAMBLE_PATTERN_NONE )
			RegValue |= BIT13;
	}

	if ( info->params.mode == MGSL_MODE_HDLC &&
		(info->params.flags & HDLC_FLAG_SHARE_ZERO) )
		RegValue |= BIT12;

	if ( info->params.addr_filter != 0xff )
	{
		/* set up receive address filtering */
		usc_OutReg( info, RSR, info->params.addr_filter );
		RegValue |= BIT4;
	}

	usc_OutReg( info, CMR, RegValue );
	info->cmr_value = RegValue;

	/* Receiver mode Register (RMR)
	 *
	 * <15..13>  000    encoding
	 * <12..11>  00     FCS = 16bit CRC CCITT (x15 + x12 + x5 + 1)
	 * <10>      1      1 = Set CRC to all 1s (use for SDLC/HDLC)
	 * <9>       0      1 = Include Receive chars in CRC
	 * <8>       1      1 = Use Abort/PE bit as abort indicator
	 * <7..6>    00     Even parity
	 * <5>       0      parity disabled
	 * <4..2>    000    Receive Char Length = 8 bits
	 * <1..0>    00     Disable Receiver
	 *
	 * 0000 0101 0000 0000 = 0x0500
	 */

	RegValue = 0x0500;

	switch ( info->params.encoding ) {
	case HDLC_ENCODING_NRZB:               RegValue |= BIT13; break;
	case HDLC_ENCODING_NRZI_MARK:          RegValue |= BIT14; break;
	case HDLC_ENCODING_NRZI_SPACE:	       RegValue |= BIT14 + BIT13; break;
	case HDLC_ENCODING_BIPHASE_MARK:       RegValue |= BIT15; break;
	case HDLC_ENCODING_BIPHASE_SPACE:      RegValue |= BIT15 + BIT13; break;
	case HDLC_ENCODING_BIPHASE_LEVEL:      RegValue |= BIT15 + BIT14; break;
	case HDLC_ENCODING_DIFF_BIPHASE_LEVEL: RegValue |= BIT15 + BIT14 + BIT13; break;
	}

	if ( (info->params.crc_type & HDLC_CRC_MASK) == HDLC_CRC_16_CCITT )
		RegValue |= BIT9;
	else if ( (info->params.crc_type & HDLC_CRC_MASK) == HDLC_CRC_32_CCITT )
		RegValue |= ( BIT12 | BIT10 | BIT9 );

	usc_OutReg( info, RMR, RegValue );

	/* Set the Receive count Limit Register (RCLR) to 0xffff. */
	/* When an opening flag of an SDLC frame is recognized the */
	/* Receive Character count (RCC) is loaded with the value in */
	/* RCLR. The RCC is decremented for each received byte.  The */
	/* value of RCC is stored after the closing flag of the frame */
	/* allowing the frame size to be computed. */

	usc_OutReg( info, RCLR, RCLRVALUE );

	usc_RCmd( info, RCmd_SelectRicrdma_level );

	/* Receive Interrupt Control Register (RICR)
	 *
	 * <15..8>	?	RxFIFO DMA Request Level
	 * <7>		0	Exited Hunt IA (Interrupt Arm)
	 * <6>		0	Idle Received IA
	 * <5>		0	Break/Abort IA
	 * <4>		0	Rx Bound IA
	 * <3>		1	Queued status reflects oldest 2 bytes in FIFO
	 * <2>		0	Abort/PE IA
	 * <1>		1	Rx Overrun IA
	 * <0>		0	Select TC0 value for readback
	 *
	 *	0000 0000 0000 1000 = 0x000a
	 */

	/* Carry over the Exit Hunt and Idle Received bits */
	/* in case they have been armed by usc_ArmEvents.   */

	RegValue = usc_InReg( info, RICR ) & 0xc0;

	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		usc_OutReg( info, RICR, (u16)(0x030a | RegValue) );
	else
		usc_OutReg( info, RICR, (u16)(0x140a | RegValue) );

	/* Unlatch all Rx status bits and clear Rx status IRQ Pending */

	usc_UnlatchRxstatusBits( info, RXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, RECEIVE_STATUS );

	/* Transmit mode Register (TMR)
	 *	
	 * <15..13>	000	encoding
	 * <12..11>	00	FCS = 16bit CRC CCITT (x15 + x12 + x5 + 1)
	 * <10>		1	1 = Start CRC as all 1s (use for SDLC/HDLC)
	 * <9>		0	1 = Tx CRC Enabled
	 * <8>		0	1 = Append CRC to end of transmit frame
	 * <7..6>	00	Transmit parity Even
	 * <5>		0	Transmit parity Disabled
	 * <4..2>	000	Tx Char Length = 8 bits
	 * <1..0>	00	Disable Transmitter
	 *
	 * 	0000 0100 0000 0000 = 0x0400
	 */

	RegValue = 0x0400;

	switch ( info->params.encoding ) {
	case HDLC_ENCODING_NRZB:               RegValue |= BIT13; break;
	case HDLC_ENCODING_NRZI_MARK:          RegValue |= BIT14; break;
	case HDLC_ENCODING_NRZI_SPACE:         RegValue |= BIT14 + BIT13; break;
	case HDLC_ENCODING_BIPHASE_MARK:       RegValue |= BIT15; break;
	case HDLC_ENCODING_BIPHASE_SPACE:      RegValue |= BIT15 + BIT13; break;
	case HDLC_ENCODING_BIPHASE_LEVEL:      RegValue |= BIT15 + BIT14; break;
	case HDLC_ENCODING_DIFF_BIPHASE_LEVEL: RegValue |= BIT15 + BIT14 + BIT13; break;
	}

	if ( (info->params.crc_type & HDLC_CRC_MASK) == HDLC_CRC_16_CCITT )
		RegValue |= BIT9 + BIT8;
	else if ( (info->params.crc_type & HDLC_CRC_MASK) == HDLC_CRC_32_CCITT )
		RegValue |= ( BIT12 | BIT10 | BIT9 | BIT8);

	usc_OutReg( info, TMR, RegValue );

	usc_set_txidle( info );


	usc_TCmd( info, TCmd_SelectTicrdma_level );

	/* Transmit Interrupt Control Register (TICR)
	 *
	 * <15..8>	?	Transmit FIFO DMA Level
	 * <7>		0	Present IA (Interrupt Arm)
	 * <6>		0	Idle Sent IA
	 * <5>		1	Abort Sent IA
	 * <4>		1	EOF/EOM Sent IA
	 * <3>		0	CRC Sent IA
	 * <2>		1	1 = Wait for SW Trigger to Start Frame
	 * <1>		1	Tx Underrun IA
	 * <0>		0	TC0 constant on read back
	 *
	 *	0000 0000 0011 0110 = 0x0036
	 */

	if ( info->bus_type == MGSL_BUS_TYPE_PCI )
		usc_OutReg( info, TICR, 0x0736 );
	else								
		usc_OutReg( info, TICR, 0x1436 );

	usc_UnlatchTxstatusBits( info, TXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS );

	/*
	** Transmit Command/Status Register (TCSR)
	**
	** <15..12>	0000	TCmd
	** <11> 	0/1	UnderWait
	** <10..08>	000	TxIdle
	** <7>		x	PreSent
	** <6>         	x	IdleSent
	** <5>         	x	AbortSent
	** <4>         	x	EOF/EOM Sent
	** <3>         	x	CRC Sent
	** <2>         	x	All Sent
	** <1>         	x	TxUnder
	** <0>         	x	TxEmpty
	** 
	** 0000 0000 0000 0000 = 0x0000
	*/
	info->tcsr_value = 0;

	if ( !PreSL1660 )
		info->tcsr_value |= TCSR_UNDERWAIT;
		
	usc_OutReg( info, TCSR, info->tcsr_value );

	/* Clock mode Control Register (CMCR)
	 *
	 * <15..14>	00	counter 1 Source = Disabled
	 * <13..12> 	00	counter 0 Source = Disabled
	 * <11..10> 	11	BRG1 Input is TxC Pin
	 * <9..8>	11	BRG0 Input is TxC Pin
	 * <7..6>	01	DPLL Input is BRG1 Output
	 * <5..3>	XXX	TxCLK comes from Port 0
	 * <2..0>   	XXX	RxCLK comes from Port 1
	 *
	 *	0000 1111 0111 0111 = 0x0f77
	 */

	RegValue = 0x0f40;

	if ( info->params.flags & HDLC_FLAG_RXC_DPLL )
		RegValue |= 0x0003;	/* RxCLK from DPLL */
	else if ( info->params.flags & HDLC_FLAG_RXC_BRG )
		RegValue |= 0x0004;	/* RxCLK from BRG0 */
 	else if ( info->params.flags & HDLC_FLAG_RXC_TXCPIN)
 		RegValue |= 0x0006;	/* RxCLK from TXC Input */
	else
		RegValue |= 0x0007;	/* RxCLK from Port1 */

	if ( info->params.flags & HDLC_FLAG_TXC_DPLL )
		RegValue |= 0x0018;	/* TxCLK from DPLL */
	else if ( info->params.flags & HDLC_FLAG_TXC_BRG )
		RegValue |= 0x0020;	/* TxCLK from BRG0 */
 	else if ( info->params.flags & HDLC_FLAG_TXC_RXCPIN)
 		RegValue |= 0x0038;	/* RxCLK from TXC Input */
	else
		RegValue |= 0x0030;	/* TxCLK from Port0 */

	usc_OutReg( info, CMCR, RegValue );


	/* Hardware Configuration Register (HCR)
	 *
	 * <15..14>	00	CTR0 Divisor:00=32,01=16,10=8,11=4
	 * <13>		0	CTR1DSel:0=CTR0Div determines CTR0Div
	 * <12>		0	CVOK:0=report code violation in biphase
	 * <11..10>	00	DPLL Divisor:00=32,01=16,10=8,11=4
	 * <9..8>	XX	DPLL mode:00=disable,01=NRZ,10=Biphase,11=Biphase Level
	 * <7..6>	00	reserved
	 * <5>		0	BRG1 mode:0=continuous,1=single cycle
	 * <4>		X	BRG1 Enable
	 * <3..2>	00	reserved
	 * <1>		0	BRG0 mode:0=continuous,1=single cycle
	 * <0>		0	BRG0 Enable
	 */

	RegValue = 0x0000;

	if ( info->params.flags & (HDLC_FLAG_RXC_DPLL + HDLC_FLAG_TXC_DPLL) ) {
		u32 XtalSpeed;
		u32 DpllDivisor;
		u16 Tc;

		/*  DPLL is enabled. Use BRG1 to provide continuous reference clock  */
		/*  for DPLL. DPLL mode in HCR is dependent on the encoding used. */

		if ( info->bus_type == MGSL_BUS_TYPE_PCI )
			XtalSpeed = 11059200;
		else
			XtalSpeed = 14745600;

		if ( info->params.flags & HDLC_FLAG_DPLL_DIV16 ) {
			DpllDivisor = 16;
			RegValue |= BIT10;
		}
		else if ( info->params.flags & HDLC_FLAG_DPLL_DIV8 ) {
			DpllDivisor = 8;
			RegValue |= BIT11;
		}
		else
			DpllDivisor = 32;

		/*  Tc = (Xtal/Speed) - 1 */
		/*  If twice the remainder of (Xtal/Speed) is greater than Speed */
		/*  then rounding up gives a more precise time constant. Instead */
		/*  of rounding up and then subtracting 1 we just don't subtract */
		/*  the one in this case. */

 		/*--------------------------------------------------
 		 * ejz: for DPLL mode, application should use the
 		 * same clock speed as the partner system, even 
 		 * though clocking is derived from the input RxData.
 		 * In case the user uses a 0 for the clock speed,
 		 * default to 0xffffffff and don't try to divide by
 		 * zero
 		 *--------------------------------------------------*/
 		if ( info->params.clock_speed )
 		{
			Tc = (u16)((XtalSpeed/DpllDivisor)/info->params.clock_speed);
			if ( !((((XtalSpeed/DpllDivisor) % info->params.clock_speed) * 2)
			       / info->params.clock_speed) )
				Tc--;
 		}
 		else
 			Tc = -1;
 				  

		/* Write 16-bit Time Constant for BRG1 */
		usc_OutReg( info, TC1R, Tc );

		RegValue |= BIT4;		/* enable BRG1 */

		switch ( info->params.encoding ) {
		case HDLC_ENCODING_NRZ:
		case HDLC_ENCODING_NRZB:
		case HDLC_ENCODING_NRZI_MARK:
		case HDLC_ENCODING_NRZI_SPACE: RegValue |= BIT8; break;
		case HDLC_ENCODING_BIPHASE_MARK:
		case HDLC_ENCODING_BIPHASE_SPACE: RegValue |= BIT9; break;
		case HDLC_ENCODING_BIPHASE_LEVEL:
		case HDLC_ENCODING_DIFF_BIPHASE_LEVEL: RegValue |= BIT9 + BIT8; break;
		}
	}

	usc_OutReg( info, HCR, RegValue );


	/* Channel Control/status Register (CCSR)
	 *
	 * <15>		X	RCC FIFO Overflow status (RO)
	 * <14>		X	RCC FIFO Not Empty status (RO)
	 * <13>		0	1 = Clear RCC FIFO (WO)
	 * <12>		X	DPLL Sync (RW)
	 * <11>		X	DPLL 2 Missed Clocks status (RO)
	 * <10>		X	DPLL 1 Missed Clock status (RO)
	 * <9..8>	00	DPLL Resync on rising and falling edges (RW)
	 * <7>		X	SDLC Loop On status (RO)
	 * <6>		X	SDLC Loop Send status (RO)
	 * <5>		1	Bypass counters for TxClk and RxClk (RW)
	 * <4..2>   	000	Last Char of SDLC frame has 8 bits (RW)
	 * <1..0>   	00	reserved
	 *
	 *	0000 0000 0010 0000 = 0x0020
	 */

	usc_OutReg( info, CCSR, 0x1020 );


	if ( info->params.flags & HDLC_FLAG_AUTO_CTS ) {
		usc_OutReg( info, SICR,
			    (u16)(usc_InReg(info,SICR) | SICR_CTS_INACTIVE) );
	}
	

	/* enable Master Interrupt Enable bit (MIE) */
	usc_EnableMasterIrqBit( info );

	usc_ClearIrqPendingBits( info, RECEIVE_STATUS + RECEIVE_DATA +
				TRANSMIT_STATUS + TRANSMIT_DATA + MISC);

	/* arm RCC underflow interrupt */
	usc_OutReg(info, SICR, (u16)(usc_InReg(info,SICR) | BIT3));
	usc_EnableInterrupts(info, MISC);

	info->mbre_bit = 0;
	outw( 0, info->io_base ); 			/* clear Master Bus Enable (DCAR) */
	usc_DmaCmd( info, DmaCmd_ResetAllChannels );	/* disable both DMA channels */
	info->mbre_bit = BIT8;
	outw( BIT8, info->io_base );			/* set Master Bus Enable (DCAR) */

	if (info->bus_type == MGSL_BUS_TYPE_ISA) {
		/* Enable DMAEN (Port 7, Bit 14) */
		/* This connects the DMA request signal to the ISA bus */
		usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT15) & ~BIT14));
	}

	/* DMA Control Register (DCR)
	 *
	 * <15..14>	10	Priority mode = Alternating Tx/Rx
	 *		01	Rx has priority
	 *		00	Tx has priority
	 *
	 * <13>		1	Enable Priority Preempt per DCR<15..14>
	 *			(WARNING DCR<11..10> must be 00 when this is 1)
	 *		0	Choose activate channel per DCR<11..10>
	 *
	 * <12>		0	Little Endian for Array/List
	 * <11..10>	00	Both Channels can use each bus grant
	 * <9..6>	0000	reserved
	 * <5>		0	7 CLK - Minimum Bus Re-request Interval
	 * <4>		0	1 = drive D/C and S/D pins
	 * <3>		1	1 = Add one wait state to all DMA cycles.
	 * <2>		0	1 = Strobe /UAS on every transfer.
	 * <1..0>	11	Addr incrementing only affects LS24 bits
	 *
	 *	0110 0000 0000 1011 = 0x600b
	 */

	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		/* PCI adapter does not need DMA wait state */
		usc_OutDmaReg( info, DCR, 0xa00b );
	}
	else
		usc_OutDmaReg( info, DCR, 0x800b );


	/* Receive DMA mode Register (RDMR)
	 *
	 * <15..14>	11	DMA mode = Linked List Buffer mode
	 * <13>		1	RSBinA/L = store Rx status Block in Arrary/List entry
	 * <12>		1	Clear count of List Entry after fetching
	 * <11..10>	00	Address mode = Increment
	 * <9>		1	Terminate Buffer on RxBound
	 * <8>		0	Bus Width = 16bits
	 * <7..0>	?	status Bits (write as 0s)
	 *
	 * 1111 0010 0000 0000 = 0xf200
	 */

	usc_OutDmaReg( info, RDMR, 0xf200 );


	/* Transmit DMA mode Register (TDMR)
	 *
	 * <15..14>	11	DMA mode = Linked List Buffer mode
	 * <13>		1	TCBinA/L = fetch Tx Control Block from List entry
	 * <12>		1	Clear count of List Entry after fetching
	 * <11..10>	00	Address mode = Increment
	 * <9>		1	Terminate Buffer on end of frame
	 * <8>		0	Bus Width = 16bits
	 * <7..0>	?	status Bits (Read Only so write as 0)
	 *
	 *	1111 0010 0000 0000 = 0xf200
	 */

	usc_OutDmaReg( info, TDMR, 0xf200 );


	/* DMA Interrupt Control Register (DICR)
	 *
	 * <15>		1	DMA Interrupt Enable
	 * <14>		0	1 = Disable IEO from USC
	 * <13>		0	1 = Don't provide vector during IntAck
	 * <12>		1	1 = Include status in Vector
	 * <10..2>	0	reserved, Must be 0s
	 * <1>		0	1 = Rx DMA Interrupt Enabled
	 * <0>		0	1 = Tx DMA Interrupt Enabled
	 *
	 *	1001 0000 0000 0000 = 0x9000
	 */

	usc_OutDmaReg( info, DICR, 0x9000 );

	usc_InDmaReg( info, RDMR );		/* clear pending receive DMA IRQ bits */
	usc_InDmaReg( info, TDMR );		/* clear pending transmit DMA IRQ bits */
	usc_OutDmaReg( info, CDIR, 0x0303 );	/* clear IUS and Pending for Tx and Rx */

	/* Channel Control Register (CCR)
	 *
	 * <15..14>	10	Use 32-bit Tx Control Blocks (TCBs)
	 * <13>		0	Trigger Tx on SW Command Disabled
	 * <12>		0	Flag Preamble Disabled
	 * <11..10>	00	Preamble Length
	 * <9..8>	00	Preamble Pattern
	 * <7..6>	10	Use 32-bit Rx status Blocks (RSBs)
	 * <5>		0	Trigger Rx on SW Command Disabled
	 * <4..0>	0	reserved
	 *
	 *	1000 0000 1000 0000 = 0x8080
	 */

	RegValue = 0x8080;

	switch ( info->params.preamble_length ) {
	case HDLC_PREAMBLE_LENGTH_16BITS: RegValue |= BIT10; break;
	case HDLC_PREAMBLE_LENGTH_32BITS: RegValue |= BIT11; break;
	case HDLC_PREAMBLE_LENGTH_64BITS: RegValue |= BIT11 + BIT10; break;
	}

	switch ( info->params.preamble ) {
	case HDLC_PREAMBLE_PATTERN_FLAGS: RegValue |= BIT8 + BIT12; break;
	case HDLC_PREAMBLE_PATTERN_ONES:  RegValue |= BIT8; break;
	case HDLC_PREAMBLE_PATTERN_10:    RegValue |= BIT9; break;
	case HDLC_PREAMBLE_PATTERN_01:    RegValue |= BIT9 + BIT8; break;
	}

	usc_OutReg( info, CCR, RegValue );


	/*
	 * Burst/Dwell Control Register
	 *
	 * <15..8>	0x20	Maximum number of transfers per bus grant
	 * <7..0>	0x00	Maximum number of clock cycles per bus grant
	 */

	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		/* don't limit bus occupancy on PCI adapter */
		usc_OutDmaReg( info, BDCR, 0x0000 );
	}
	else
		usc_OutDmaReg( info, BDCR, 0x2000 );

	usc_stop_transmitter(info);
	usc_stop_receiver(info);
	
}	/* end of usc_set_sdlc_mode() */

/* usc_enable_loopback()
 *
 * Set the 16C32 for internal loopback mode.
 * The TxCLK and RxCLK signals are generated from the BRG0 and
 * the TxD is looped back to the RxD internally.
 *
 * Arguments:		info	pointer to device instance data
 *			enable	1 = enable loopback, 0 = disable
 * Return Value:	None
 */
static void usc_enable_loopback(struct mgsl_struct *info, int enable)
{
	if (enable) {
		/* blank external TXD output */
		usc_OutReg(info,IOCR,usc_InReg(info,IOCR) | (BIT7+BIT6));
	
		/* Clock mode Control Register (CMCR)
		 *
		 * <15..14>	00	counter 1 Disabled
		 * <13..12> 	00	counter 0 Disabled
		 * <11..10> 	11	BRG1 Input is TxC Pin
		 * <9..8>	11	BRG0 Input is TxC Pin
		 * <7..6>	01	DPLL Input is BRG1 Output
		 * <5..3>	100	TxCLK comes from BRG0
		 * <2..0>   	100	RxCLK comes from BRG0
		 *
		 * 0000 1111 0110 0100 = 0x0f64
		 */

		usc_OutReg( info, CMCR, 0x0f64 );

		/* Write 16-bit Time Constant for BRG0 */
		/* use clock speed if available, otherwise use 8 for diagnostics */
		if (info->params.clock_speed) {
			if (info->bus_type == MGSL_BUS_TYPE_PCI)
				usc_OutReg(info, TC0R, (u16)((11059200/info->params.clock_speed)-1));
			else
				usc_OutReg(info, TC0R, (u16)((14745600/info->params.clock_speed)-1));
		} else
			usc_OutReg(info, TC0R, (u16)8);

		/* Hardware Configuration Register (HCR) Clear Bit 1, BRG0
		   mode = Continuous Set Bit 0 to enable BRG0.  */
		usc_OutReg( info, HCR, (u16)((usc_InReg( info, HCR ) & ~BIT1) | BIT0) );

		/* Input/Output Control Reg, <2..0> = 100, Drive RxC pin with BRG0 */
		usc_OutReg(info, IOCR, (u16)((usc_InReg(info, IOCR) & 0xfff8) | 0x0004));

		/* set Internal Data loopback mode */
		info->loopback_bits = 0x300;
		outw( 0x0300, info->io_base + CCAR );
	} else {
		/* enable external TXD output */
		usc_OutReg(info,IOCR,usc_InReg(info,IOCR) & ~(BIT7+BIT6));
	
		/* clear Internal Data loopback mode */
		info->loopback_bits = 0;
		outw( 0,info->io_base + CCAR );
	}
	
}	/* end of usc_enable_loopback() */

/* usc_enable_aux_clock()
 *
 * Enabled the AUX clock output at the specified frequency.
 *
 * Arguments:
 *
 *	info		pointer to device extension
 *	data_rate	data rate of clock in bits per second
 *			A data rate of 0 disables the AUX clock.
 *
 * Return Value:	None
 */
static void usc_enable_aux_clock( struct mgsl_struct *info, u32 data_rate )
{
	u32 XtalSpeed;
	u16 Tc;

	if ( data_rate ) {
		if ( info->bus_type == MGSL_BUS_TYPE_PCI )
			XtalSpeed = 11059200;
		else
			XtalSpeed = 14745600;


		/* Tc = (Xtal/Speed) - 1 */
		/* If twice the remainder of (Xtal/Speed) is greater than Speed */
		/* then rounding up gives a more precise time constant. Instead */
		/* of rounding up and then subtracting 1 we just don't subtract */
		/* the one in this case. */


		Tc = (u16)(XtalSpeed/data_rate);
		if ( !(((XtalSpeed % data_rate) * 2) / data_rate) )
			Tc--;

		/* Write 16-bit Time Constant for BRG0 */
		usc_OutReg( info, TC0R, Tc );

		/*
		 * Hardware Configuration Register (HCR)
		 * Clear Bit 1, BRG0 mode = Continuous
		 * Set Bit 0 to enable BRG0.
		 */

		usc_OutReg( info, HCR, (u16)((usc_InReg( info, HCR ) & ~BIT1) | BIT0) );

		/* Input/Output Control Reg, <2..0> = 100, Drive RxC pin with BRG0 */
		usc_OutReg( info, IOCR, (u16)((usc_InReg(info, IOCR) & 0xfff8) | 0x0004) );
	} else {
		/* data rate == 0 so turn off BRG0 */
		usc_OutReg( info, HCR, (u16)(usc_InReg( info, HCR ) & ~BIT0) );
	}

}	/* end of usc_enable_aux_clock() */

/*
 *
 * usc_process_rxoverrun_sync()
 *
 *		This function processes a receive overrun by resetting the
 *		receive DMA buffers and issuing a Purge Rx FIFO command
 *		to allow the receiver to continue receiving.
 *
 * Arguments:
 *
 *	info		pointer to device extension
 *
 * Return Value: None
 */
static void usc_process_rxoverrun_sync( struct mgsl_struct *info )
{
	int start_index;
	int end_index;
	int frame_start_index;
	bool start_of_frame_found = false;
	bool end_of_frame_found = false;
	bool reprogram_dma = false;

	DMABUFFERENTRY *buffer_list = info->rx_buffer_list;
	u32 phys_addr;

	usc_DmaCmd( info, DmaCmd_PauseRxChannel );
	usc_RCmd( info, RCmd_EnterHuntmode );
	usc_RTCmd( info, RTCmd_PurgeRxFifo );

	/* CurrentRxBuffer points to the 1st buffer of the next */
	/* possibly available receive frame. */
	
	frame_start_index = start_index = end_index = info->current_rx_buffer;

	/* Search for an unfinished string of buffers. This means */
	/* that a receive frame started (at least one buffer with */
	/* count set to zero) but there is no terminiting buffer */
	/* (status set to non-zero). */

	while( !buffer_list[end_index].count )
	{
		/* Count field has been reset to zero by 16C32. */
		/* This buffer is currently in use. */

		if ( !start_of_frame_found )
		{
			start_of_frame_found = true;
			frame_start_index = end_index;
			end_of_frame_found = false;
		}

		if ( buffer_list[end_index].status )
		{
			/* Status field has been set by 16C32. */
			/* This is the last buffer of a received frame. */

			/* We want to leave the buffers for this frame intact. */
			/* Move on to next possible frame. */

			start_of_frame_found = false;
			end_of_frame_found = true;
		}

  		/* advance to next buffer entry in linked list */
  		end_index++;
  		if ( end_index == info->rx_buffer_count )
  			end_index = 0;

		if ( start_index == end_index )
		{
			/* The entire list has been searched with all Counts == 0 and */
			/* all Status == 0. The receive buffers are */
			/* completely screwed, reset all receive buffers! */
			mgsl_reset_rx_dma_buffers( info );
			frame_start_index = 0;
			start_of_frame_found = false;
			reprogram_dma = true;
			break;
		}
	}

	if ( start_of_frame_found && !end_of_frame_found )
	{
		/* There is an unfinished string of receive DMA buffers */
		/* as a result of the receiver overrun. */

		/* Reset the buffers for the unfinished frame */
		/* and reprogram the receive DMA controller to start */
		/* at the 1st buffer of unfinished frame. */

		start_index = frame_start_index;

		do
		{
			*((unsigned long *)&(info->rx_buffer_list[start_index++].count)) = DMABUFFERSIZE;

  			/* Adjust index for wrap around. */
  			if ( start_index == info->rx_buffer_count )
  				start_index = 0;

		} while( start_index != end_index );

		reprogram_dma = true;
	}

	if ( reprogram_dma )
	{
		usc_UnlatchRxstatusBits(info,RXSTATUS_ALL);
		usc_ClearIrqPendingBits(info, RECEIVE_DATA|RECEIVE_STATUS);
		usc_UnlatchRxstatusBits(info, RECEIVE_DATA|RECEIVE_STATUS);
		
		usc_EnableReceiver(info,DISABLE_UNCONDITIONAL);
		
		/* This empties the receive FIFO and loads the RCC with RCLR */
		usc_OutReg( info, CCSR, (u16)(usc_InReg(info,CCSR) | BIT13) );

		/* program 16C32 with physical address of 1st DMA buffer entry */
		phys_addr = info->rx_buffer_list[frame_start_index].phys_entry;
		usc_OutDmaReg( info, NRARL, (u16)phys_addr );
		usc_OutDmaReg( info, NRARU, (u16)(phys_addr >> 16) );

		usc_UnlatchRxstatusBits( info, RXSTATUS_ALL );
		usc_ClearIrqPendingBits( info, RECEIVE_DATA + RECEIVE_STATUS );
		usc_EnableInterrupts( info, RECEIVE_STATUS );

		/* 1. Arm End of Buffer (EOB) Receive DMA Interrupt (BIT2 of RDIAR) */
		/* 2. Enable Receive DMA Interrupts (BIT1 of DICR) */

		usc_OutDmaReg( info, RDIAR, BIT3 + BIT2 );
		usc_OutDmaReg( info, DICR, (u16)(usc_InDmaReg(info,DICR) | BIT1) );
		usc_DmaCmd( info, DmaCmd_InitRxChannel );
		if ( info->params.flags & HDLC_FLAG_AUTO_DCD )
			usc_EnableReceiver(info,ENABLE_AUTO_DCD);
		else
			usc_EnableReceiver(info,ENABLE_UNCONDITIONAL);
	}
	else
	{
		/* This empties the receive FIFO and loads the RCC with RCLR */
		usc_OutReg( info, CCSR, (u16)(usc_InReg(info,CCSR) | BIT13) );
		usc_RTCmd( info, RTCmd_PurgeRxFifo );
	}

}	/* end of usc_process_rxoverrun_sync() */

/* usc_stop_receiver()
 *
 *	Disable USC receiver
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_stop_receiver( struct mgsl_struct *info )
{
	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):usc_stop_receiver(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	/* Disable receive DMA channel. */
	/* This also disables receive DMA channel interrupts */
	usc_DmaCmd( info, DmaCmd_ResetRxChannel );

	usc_UnlatchRxstatusBits( info, RXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, RECEIVE_DATA + RECEIVE_STATUS );
	usc_DisableInterrupts( info, RECEIVE_DATA + RECEIVE_STATUS );

	usc_EnableReceiver(info,DISABLE_UNCONDITIONAL);

	/* This empties the receive FIFO and loads the RCC with RCLR */
	usc_OutReg( info, CCSR, (u16)(usc_InReg(info,CCSR) | BIT13) );
	usc_RTCmd( info, RTCmd_PurgeRxFifo );

	info->rx_enabled = false;
	info->rx_overflow = false;
	info->rx_rcc_underrun = false;
	
}	/* end of stop_receiver() */

/* usc_start_receiver()
 *
 *	Enable the USC receiver 
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_start_receiver( struct mgsl_struct *info )
{
	u32 phys_addr;
	
	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):usc_start_receiver(%s)\n",
			 __FILE__,__LINE__, info->device_name );

	mgsl_reset_rx_dma_buffers( info );
	usc_stop_receiver( info );

	usc_OutReg( info, CCSR, (u16)(usc_InReg(info,CCSR) | BIT13) );
	usc_RTCmd( info, RTCmd_PurgeRxFifo );

	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		/* DMA mode Transfers */
		/* Program the DMA controller. */
		/* Enable the DMA controller end of buffer interrupt. */

		/* program 16C32 with physical address of 1st DMA buffer entry */
		phys_addr = info->rx_buffer_list[0].phys_entry;
		usc_OutDmaReg( info, NRARL, (u16)phys_addr );
		usc_OutDmaReg( info, NRARU, (u16)(phys_addr >> 16) );

		usc_UnlatchRxstatusBits( info, RXSTATUS_ALL );
		usc_ClearIrqPendingBits( info, RECEIVE_DATA + RECEIVE_STATUS );
		usc_EnableInterrupts( info, RECEIVE_STATUS );

		/* 1. Arm End of Buffer (EOB) Receive DMA Interrupt (BIT2 of RDIAR) */
		/* 2. Enable Receive DMA Interrupts (BIT1 of DICR) */

		usc_OutDmaReg( info, RDIAR, BIT3 + BIT2 );
		usc_OutDmaReg( info, DICR, (u16)(usc_InDmaReg(info,DICR) | BIT1) );
		usc_DmaCmd( info, DmaCmd_InitRxChannel );
		if ( info->params.flags & HDLC_FLAG_AUTO_DCD )
			usc_EnableReceiver(info,ENABLE_AUTO_DCD);
		else
			usc_EnableReceiver(info,ENABLE_UNCONDITIONAL);
	} else {
		usc_UnlatchRxstatusBits(info, RXSTATUS_ALL);
		usc_ClearIrqPendingBits(info, RECEIVE_DATA + RECEIVE_STATUS);
		usc_EnableInterrupts(info, RECEIVE_DATA);

		usc_RTCmd( info, RTCmd_PurgeRxFifo );
		usc_RCmd( info, RCmd_EnterHuntmode );

		usc_EnableReceiver(info,ENABLE_UNCONDITIONAL);
	}

	usc_OutReg( info, CCSR, 0x1020 );

	info->rx_enabled = true;

}	/* end of usc_start_receiver() */

/* usc_start_transmitter()
 *
 *	Enable the USC transmitter and send a transmit frame if
 *	one is loaded in the DMA buffers.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_start_transmitter( struct mgsl_struct *info )
{
	u32 phys_addr;
	unsigned int FrameSize;

	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):usc_start_transmitter(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	if ( info->xmit_cnt ) {

		/* If auto RTS enabled and RTS is inactive, then assert */
		/* RTS and set a flag indicating that the driver should */
		/* negate RTS when the transmission completes. */

		info->drop_rts_on_tx_done = false;

		if ( info->params.flags & HDLC_FLAG_AUTO_RTS ) {
			usc_get_serial_signals( info );
			if ( !(info->serial_signals & SerialSignal_RTS) ) {
				info->serial_signals |= SerialSignal_RTS;
				usc_set_serial_signals( info );
				info->drop_rts_on_tx_done = true;
			}
		}


		if ( info->params.mode == MGSL_MODE_ASYNC ) {
			if ( !info->tx_active ) {
				usc_UnlatchTxstatusBits(info, TXSTATUS_ALL);
				usc_ClearIrqPendingBits(info, TRANSMIT_STATUS + TRANSMIT_DATA);
				usc_EnableInterrupts(info, TRANSMIT_DATA);
				usc_load_txfifo(info);
			}
		} else {
			/* Disable transmit DMA controller while programming. */
			usc_DmaCmd( info, DmaCmd_ResetTxChannel );
			
			/* Transmit DMA buffer is loaded, so program USC */
			/* to send the frame contained in the buffers.	 */

			FrameSize = info->tx_buffer_list[info->start_tx_dma_buffer].rcc;

			/* if operating in Raw sync mode, reset the rcc component
			 * of the tx dma buffer entry, otherwise, the serial controller
			 * will send a closing sync char after this count.
			 */
	    		if ( info->params.mode == MGSL_MODE_RAW )
				info->tx_buffer_list[info->start_tx_dma_buffer].rcc = 0;

			/* Program the Transmit Character Length Register (TCLR) */
			/* and clear FIFO (TCC is loaded with TCLR on FIFO clear) */
			usc_OutReg( info, TCLR, (u16)FrameSize );

			usc_RTCmd( info, RTCmd_PurgeTxFifo );

			/* Program the address of the 1st DMA Buffer Entry in linked list */
			phys_addr = info->tx_buffer_list[info->start_tx_dma_buffer].phys_entry;
			usc_OutDmaReg( info, NTARL, (u16)phys_addr );
			usc_OutDmaReg( info, NTARU, (u16)(phys_addr >> 16) );

			usc_UnlatchTxstatusBits( info, TXSTATUS_ALL );
			usc_ClearIrqPendingBits( info, TRANSMIT_STATUS );
			usc_EnableInterrupts( info, TRANSMIT_STATUS );

			if ( info->params.mode == MGSL_MODE_RAW &&
					info->num_tx_dma_buffers > 1 ) {
			   /* When running external sync mode, attempt to 'stream' transmit  */
			   /* by filling tx dma buffers as they become available. To do this */
			   /* we need to enable Tx DMA EOB Status interrupts :               */
			   /*                                                                */
			   /* 1. Arm End of Buffer (EOB) Transmit DMA Interrupt (BIT2 of TDIAR) */
			   /* 2. Enable Transmit DMA Interrupts (BIT0 of DICR) */

			   usc_OutDmaReg( info, TDIAR, BIT2|BIT3 );
			   usc_OutDmaReg( info, DICR, (u16)(usc_InDmaReg(info,DICR) | BIT0) );
			}

			/* Initialize Transmit DMA Channel */
			usc_DmaCmd( info, DmaCmd_InitTxChannel );
			
			usc_TCmd( info, TCmd_SendFrame );
			
			mod_timer(&info->tx_timer, jiffies +
					msecs_to_jiffies(5000));
		}
		info->tx_active = true;
	}

	if ( !info->tx_enabled ) {
		info->tx_enabled = true;
		if ( info->params.flags & HDLC_FLAG_AUTO_CTS )
			usc_EnableTransmitter(info,ENABLE_AUTO_CTS);
		else
			usc_EnableTransmitter(info,ENABLE_UNCONDITIONAL);
	}

}	/* end of usc_start_transmitter() */

/* usc_stop_transmitter()
 *
 *	Stops the transmitter and DMA
 *
 * Arguments:		info	pointer to device isntance data
 * Return Value:	None
 */
static void usc_stop_transmitter( struct mgsl_struct *info )
{
	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):usc_stop_transmitter(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	del_timer(&info->tx_timer);	
			 
	usc_UnlatchTxstatusBits( info, TXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS + TRANSMIT_DATA );
	usc_DisableInterrupts( info, TRANSMIT_STATUS + TRANSMIT_DATA );

	usc_EnableTransmitter(info,DISABLE_UNCONDITIONAL);
	usc_DmaCmd( info, DmaCmd_ResetTxChannel );
	usc_RTCmd( info, RTCmd_PurgeTxFifo );

	info->tx_enabled = false;
	info->tx_active = false;

}	/* end of usc_stop_transmitter() */

/* usc_load_txfifo()
 *
 *	Fill the transmit FIFO until the FIFO is full or
 *	there is no more data to load.
 *
 * Arguments:		info	pointer to device extension (instance data)
 * Return Value:	None
 */
static void usc_load_txfifo( struct mgsl_struct *info )
{
	int Fifocount;
	u8 TwoBytes[2];
	
	if ( !info->xmit_cnt && !info->x_char )
		return; 
		
	/* Select transmit FIFO status readback in TICR */
	usc_TCmd( info, TCmd_SelectTicrTxFifostatus );

	/* load the Transmit FIFO until FIFOs full or all data sent */

	while( (Fifocount = usc_InReg(info, TICR) >> 8) && info->xmit_cnt ) {
		/* there is more space in the transmit FIFO and */
		/* there is more data in transmit buffer */

		if ( (info->xmit_cnt > 1) && (Fifocount > 1) && !info->x_char ) {
 			/* write a 16-bit word from transmit buffer to 16C32 */
				
			TwoBytes[0] = info->xmit_buf[info->xmit_tail++];
			info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
			TwoBytes[1] = info->xmit_buf[info->xmit_tail++];
			info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
			
			outw( *((u16 *)TwoBytes), info->io_base + DATAREG);
				
			info->xmit_cnt -= 2;
			info->icount.tx += 2;
		} else {
			/* only 1 byte left to transmit or 1 FIFO slot left */
			
			outw( (inw( info->io_base + CCAR) & 0x0780) | (TDR+LSBONLY),
				info->io_base + CCAR );
			
			if (info->x_char) {
				/* transmit pending high priority char */
				outw( info->x_char,info->io_base + CCAR );
				info->x_char = 0;
			} else {
				outw( info->xmit_buf[info->xmit_tail++],info->io_base + CCAR );
				info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
				info->xmit_cnt--;
			}
			info->icount.tx++;
		}
	}

}	/* end of usc_load_txfifo() */

/* usc_reset()
 *
 *	Reset the adapter to a known state and prepare it for further use.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_reset( struct mgsl_struct *info )
{
	if ( info->bus_type == MGSL_BUS_TYPE_PCI ) {
		int i;
		u32 readval;

		/* Set BIT30 of Misc Control Register */
		/* (Local Control Register 0x50) to force reset of USC. */

		volatile u32 *MiscCtrl = (u32 *)(info->lcr_base + 0x50);
		u32 *LCR0BRDR = (u32 *)(info->lcr_base + 0x28);

		info->misc_ctrl_value |= BIT30;
		*MiscCtrl = info->misc_ctrl_value;

		/*
		 * Force at least 170ns delay before clearing 
		 * reset bit. Each read from LCR takes at least 
		 * 30ns so 10 times for 300ns to be safe.
		 */
		for(i=0;i<10;i++)
			readval = *MiscCtrl;

		info->misc_ctrl_value &= ~BIT30;
		*MiscCtrl = info->misc_ctrl_value;

		*LCR0BRDR = BUS_DESCRIPTOR(
			1,		// Write Strobe Hold (0-3)
			2,		// Write Strobe Delay (0-3)
			2,		// Read Strobe Delay  (0-3)
			0,		// NWDD (Write data-data) (0-3)
			4,		// NWAD (Write Addr-data) (0-31)
			0,		// NXDA (Read/Write Data-Addr) (0-3)
			0,		// NRDD (Read Data-Data) (0-3)
			5		// NRAD (Read Addr-Data) (0-31)
			);
	} else {
		/* do HW reset */
		outb( 0,info->io_base + 8 );
	}

	info->mbre_bit = 0;
	info->loopback_bits = 0;
	info->usc_idle_mode = 0;

	/*
	 * Program the Bus Configuration Register (BCR)
	 *
	 * <15>		0	Don't use separate address
	 * <14..6>	0	reserved
	 * <5..4>	00	IAckmode = Default, don't care
	 * <3>		1	Bus Request Totem Pole output
	 * <2>		1	Use 16 Bit data bus
	 * <1>		0	IRQ Totem Pole output
	 * <0>		0	Don't Shift Right Addr
	 *
	 * 0000 0000 0000 1100 = 0x000c
	 *
	 * By writing to io_base + SDPIN the Wait/Ack pin is
	 * programmed to work as a Wait pin.
	 */
	
	outw( 0x000c,info->io_base + SDPIN );


	outw( 0,info->io_base );
	outw( 0,info->io_base + CCAR );

	/* select little endian byte ordering */
	usc_RTCmd( info, RTCmd_SelectLittleEndian );


	/* Port Control Register (PCR)
	 *
	 * <15..14>	11	Port 7 is Output (~DMAEN, Bit 14 : 0 = Enabled)
	 * <13..12>	11	Port 6 is Output (~INTEN, Bit 12 : 0 = Enabled)
	 * <11..10> 	00	Port 5 is Input (No Connect, Don't Care)
	 * <9..8> 	00	Port 4 is Input (No Connect, Don't Care)
	 * <7..6>	11	Port 3 is Output (~RTS, Bit 6 : 0 = Enabled )
	 * <5..4>	11	Port 2 is Output (~DTR, Bit 4 : 0 = Enabled )
	 * <3..2>	01	Port 1 is Input (Dedicated RxC)
	 * <1..0>	01	Port 0 is Input (Dedicated TxC)
	 *
	 *	1111 0000 1111 0101 = 0xf0f5
	 */

	usc_OutReg( info, PCR, 0xf0f5 );


	/*
	 * Input/Output Control Register
	 *
	 * <15..14>	00	CTS is active low input
	 * <13..12>	00	DCD is active low input
	 * <11..10>	00	TxREQ pin is input (DSR)
	 * <9..8>	00	RxREQ pin is input (RI)
	 * <7..6>	00	TxD is output (Transmit Data)
	 * <5..3>	000	TxC Pin in Input (14.7456MHz Clock)
	 * <2..0>	100	RxC is Output (drive with BRG0)
	 *
	 *	0000 0000 0000 0100 = 0x0004
	 */

	usc_OutReg( info, IOCR, 0x0004 );

}	/* end of usc_reset() */

/* usc_set_async_mode()
 *
 *	Program adapter for asynchronous communications.
 *
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void usc_set_async_mode( struct mgsl_struct *info )
{
	u16 RegValue;

	/* disable interrupts while programming USC */
	usc_DisableMasterIrqBit( info );

	outw( 0, info->io_base ); 			/* clear Master Bus Enable (DCAR) */
	usc_DmaCmd( info, DmaCmd_ResetAllChannels );	/* disable both DMA channels */

	usc_loopback_frame( info );

	/* Channel mode Register (CMR)
	 *
	 * <15..14>	00	Tx Sub modes, 00 = 1 Stop Bit
	 * <13..12>	00	              00 = 16X Clock
	 * <11..8>	0000	Transmitter mode = Asynchronous
	 * <7..6>	00	reserved?
	 * <5..4>	00	Rx Sub modes, 00 = 16X Clock
	 * <3..0>	0000	Receiver mode = Asynchronous
	 *
	 * 0000 0000 0000 0000 = 0x0
	 */

	RegValue = 0;
	if ( info->params.stop_bits != 1 )
		RegValue |= BIT14;
	usc_OutReg( info, CMR, RegValue );

	
	/* Receiver mode Register (RMR)
	 *
	 * <15..13>	000	encoding = None
	 * <12..08>	00000	reserved (Sync Only)
	 * <7..6>   	00	Even parity
	 * <5>		0	parity disabled
	 * <4..2>	000	Receive Char Length = 8 bits
	 * <1..0>	00	Disable Receiver
	 *
	 * 0000 0000 0000 0000 = 0x0
	 */

	RegValue = 0;

	if ( info->params.data_bits != 8 )
		RegValue |= BIT4+BIT3+BIT2;

	if ( info->params.parity != ASYNC_PARITY_NONE ) {
		RegValue |= BIT5;
		if ( info->params.parity != ASYNC_PARITY_ODD )
			RegValue |= BIT6;
	}

	usc_OutReg( info, RMR, RegValue );


	/* Set IRQ trigger level */

	usc_RCmd( info, RCmd_SelectRicrIntLevel );

	
	/* Receive Interrupt Control Register (RICR)
	 *
	 * <15..8>	?		RxFIFO IRQ Request Level
	 *
	 * Note: For async mode the receive FIFO level must be set
	 * to 0 to avoid the situation where the FIFO contains fewer bytes
	 * than the trigger level and no more data is expected.
	 *
	 * <7>		0		Exited Hunt IA (Interrupt Arm)
	 * <6>		0		Idle Received IA
	 * <5>		0		Break/Abort IA
	 * <4>		0		Rx Bound IA
	 * <3>		0		Queued status reflects oldest byte in FIFO
	 * <2>		0		Abort/PE IA
	 * <1>		0		Rx Overrun IA
	 * <0>		0		Select TC0 value for readback
	 *
	 * 0000 0000 0100 0000 = 0x0000 + (FIFOLEVEL in MSB)
	 */
	
	usc_OutReg( info, RICR, 0x0000 );

	usc_UnlatchRxstatusBits( info, RXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, RECEIVE_STATUS );

	
	/* Transmit mode Register (TMR)
	 *
	 * <15..13>	000	encoding = None
	 * <12..08>	00000	reserved (Sync Only)
	 * <7..6>	00	Transmit parity Even
	 * <5>		0	Transmit parity Disabled
	 * <4..2>	000	Tx Char Length = 8 bits
	 * <1..0>	00	Disable Transmitter
	 *
	 * 0000 0000 0000 0000 = 0x0
	 */

	RegValue = 0;

	if ( info->params.data_bits != 8 )
		RegValue |= BIT4+BIT3+BIT2;

	if ( info->params.parity != ASYNC_PARITY_NONE ) {
		RegValue |= BIT5;
		if ( info->params.parity != ASYNC_PARITY_ODD )
			RegValue |= BIT6;
	}

	usc_OutReg( info, TMR, RegValue );

	usc_set_txidle( info );


	/* Set IRQ trigger level */

	usc_TCmd( info, TCmd_SelectTicrIntLevel );

	
	/* Transmit Interrupt Control Register (TICR)
	 *
	 * <15..8>	?	Transmit FIFO IRQ Level
	 * <7>		0	Present IA (Interrupt Arm)
	 * <6>		1	Idle Sent IA
	 * <5>		0	Abort Sent IA
	 * <4>		0	EOF/EOM Sent IA
	 * <3>		0	CRC Sent IA
	 * <2>		0	1 = Wait for SW Trigger to Start Frame
	 * <1>		0	Tx Underrun IA
	 * <0>		0	TC0 constant on read back
	 *
	 *	0000 0000 0100 0000 = 0x0040
	 */

	usc_OutReg( info, TICR, 0x1f40 );

	usc_UnlatchTxstatusBits( info, TXSTATUS_ALL );
	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS );

	usc_enable_async_clock( info, info->params.data_rate );

	
	/* Channel Control/status Register (CCSR)
	 *
	 * <15>		X	RCC FIFO Overflow status (RO)
	 * <14>		X	RCC FIFO Not Empty status (RO)
	 * <13>		0	1 = Clear RCC FIFO (WO)
	 * <12>		X	DPLL in Sync status (RO)
	 * <11>		X	DPLL 2 Missed Clocks status (RO)
	 * <10>		X	DPLL 1 Missed Clock status (RO)
	 * <9..8>	00	DPLL Resync on rising and falling edges (RW)
	 * <7>		X	SDLC Loop On status (RO)
	 * <6>		X	SDLC Loop Send status (RO)
	 * <5>		1	Bypass counters for TxClk and RxClk (RW)
	 * <4..2>   	000	Last Char of SDLC frame has 8 bits (RW)
	 * <1..0>   	00	reserved
	 *
	 *	0000 0000 0010 0000 = 0x0020
	 */
	
	usc_OutReg( info, CCSR, 0x0020 );

	usc_DisableInterrupts( info, TRANSMIT_STATUS + TRANSMIT_DATA +
			      RECEIVE_DATA + RECEIVE_STATUS );

	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS + TRANSMIT_DATA +
				RECEIVE_DATA + RECEIVE_STATUS );

	usc_EnableMasterIrqBit( info );

	if (info->bus_type == MGSL_BUS_TYPE_ISA) {
		/* Enable INTEN (Port 6, Bit12) */
		/* This connects the IRQ request signal to the ISA bus */
		usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT13) & ~BIT12));
	}

	if (info->params.loopback) {
		info->loopback_bits = 0x300;
		outw(0x0300, info->io_base + CCAR);
	}

}	/* end of usc_set_async_mode() */

/* usc_loopback_frame()
 *
 *	Loop back a small (2 byte) dummy SDLC frame.
 *	Interrupts and DMA are NOT used. The purpose of this is to
 *	clear any 'stale' status info left over from running in	async mode.
 *
 *	The 16C32 shows the strange behaviour of marking the 1st
 *	received SDLC frame with a CRC error even when there is no
 *	CRC error. To get around this a small dummy from of 2 bytes
 *	is looped back when switching from async to sync mode.
 *
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void usc_loopback_frame( struct mgsl_struct *info )
{
	int i;
	unsigned long oldmode = info->params.mode;

	info->params.mode = MGSL_MODE_HDLC;
	
	usc_DisableMasterIrqBit( info );

	usc_set_sdlc_mode( info );
	usc_enable_loopback( info, 1 );

	/* Write 16-bit Time Constant for BRG0 */
	usc_OutReg( info, TC0R, 0 );
	
	/* Channel Control Register (CCR)
	 *
	 * <15..14>	00	Don't use 32-bit Tx Control Blocks (TCBs)
	 * <13>		0	Trigger Tx on SW Command Disabled
	 * <12>		0	Flag Preamble Disabled
	 * <11..10>	00	Preamble Length = 8-Bits
	 * <9..8>	01	Preamble Pattern = flags
	 * <7..6>	10	Don't use 32-bit Rx status Blocks (RSBs)
	 * <5>		0	Trigger Rx on SW Command Disabled
	 * <4..0>	0	reserved
	 *
	 *	0000 0001 0000 0000 = 0x0100
	 */

	usc_OutReg( info, CCR, 0x0100 );

	/* SETUP RECEIVER */
	usc_RTCmd( info, RTCmd_PurgeRxFifo );
	usc_EnableReceiver(info,ENABLE_UNCONDITIONAL);

	/* SETUP TRANSMITTER */
	/* Program the Transmit Character Length Register (TCLR) */
	/* and clear FIFO (TCC is loaded with TCLR on FIFO clear) */
	usc_OutReg( info, TCLR, 2 );
	usc_RTCmd( info, RTCmd_PurgeTxFifo );

	/* unlatch Tx status bits, and start transmit channel. */
	usc_UnlatchTxstatusBits(info,TXSTATUS_ALL);
	outw(0,info->io_base + DATAREG);

	/* ENABLE TRANSMITTER */
	usc_TCmd( info, TCmd_SendFrame );
	usc_EnableTransmitter(info,ENABLE_UNCONDITIONAL);
							
	/* WAIT FOR RECEIVE COMPLETE */
	for (i=0 ; i<1000 ; i++)
		if (usc_InReg( info, RCSR ) & (BIT8 + BIT4 + BIT3 + BIT1))
			break;

	/* clear Internal Data loopback mode */
	usc_enable_loopback(info, 0);

	usc_EnableMasterIrqBit(info);

	info->params.mode = oldmode;

}	/* end of usc_loopback_frame() */

/* usc_set_sync_mode()	Programs the USC for SDLC communications.
 *
 * Arguments:		info	pointer to adapter info structure
 * Return Value:	None
 */
static void usc_set_sync_mode( struct mgsl_struct *info )
{
	usc_loopback_frame( info );
	usc_set_sdlc_mode( info );

	if (info->bus_type == MGSL_BUS_TYPE_ISA) {
		/* Enable INTEN (Port 6, Bit12) */
		/* This connects the IRQ request signal to the ISA bus */
		usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT13) & ~BIT12));
	}

	usc_enable_aux_clock(info, info->params.clock_speed);

	if (info->params.loopback)
		usc_enable_loopback(info,1);

}	/* end of mgsl_set_sync_mode() */

/* usc_set_txidle()	Set the HDLC idle mode for the transmitter.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_set_txidle( struct mgsl_struct *info )
{
	u16 usc_idle_mode = IDLEMODE_FLAGS;

	/* Map API idle mode to USC register bits */

	switch( info->idle_mode ){
	case HDLC_TXIDLE_FLAGS:			usc_idle_mode = IDLEMODE_FLAGS; break;
	case HDLC_TXIDLE_ALT_ZEROS_ONES:	usc_idle_mode = IDLEMODE_ALT_ONE_ZERO; break;
	case HDLC_TXIDLE_ZEROS:			usc_idle_mode = IDLEMODE_ZERO; break;
	case HDLC_TXIDLE_ONES:			usc_idle_mode = IDLEMODE_ONE; break;
	case HDLC_TXIDLE_ALT_MARK_SPACE:	usc_idle_mode = IDLEMODE_ALT_MARK_SPACE; break;
	case HDLC_TXIDLE_SPACE:			usc_idle_mode = IDLEMODE_SPACE; break;
	case HDLC_TXIDLE_MARK:			usc_idle_mode = IDLEMODE_MARK; break;
	}

	info->usc_idle_mode = usc_idle_mode;
	//usc_OutReg(info, TCSR, usc_idle_mode);
	info->tcsr_value &= ~IDLEMODE_MASK;	/* clear idle mode bits */
	info->tcsr_value += usc_idle_mode;
	usc_OutReg(info, TCSR, info->tcsr_value);

	/*
	 * if SyncLink WAN adapter is running in external sync mode, the
	 * transmitter has been set to Monosync in order to try to mimic
	 * a true raw outbound bit stream. Monosync still sends an open/close
	 * sync char at the start/end of a frame. Try to match those sync
	 * patterns to the idle mode set here
	 */
	if ( info->params.mode == MGSL_MODE_RAW ) {
		unsigned char syncpat = 0;
		switch( info->idle_mode ) {
		case HDLC_TXIDLE_FLAGS:
			syncpat = 0x7e;
			break;
		case HDLC_TXIDLE_ALT_ZEROS_ONES:
			syncpat = 0x55;
			break;
		case HDLC_TXIDLE_ZEROS:
		case HDLC_TXIDLE_SPACE:
			syncpat = 0x00;
			break;
		case HDLC_TXIDLE_ONES:
		case HDLC_TXIDLE_MARK:
			syncpat = 0xff;
			break;
		case HDLC_TXIDLE_ALT_MARK_SPACE:
			syncpat = 0xaa;
			break;
		}

		usc_SetTransmitSyncChars(info,syncpat,syncpat);
	}

}	/* end of usc_set_txidle() */

/* usc_get_serial_signals()
 *
 *	Query the adapter for the state of the V24 status (input) signals.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_get_serial_signals( struct mgsl_struct *info )
{
	u16 status;

	/* clear all serial signals except DTR and RTS */
	info->serial_signals &= SerialSignal_DTR + SerialSignal_RTS;

	/* Read the Misc Interrupt status Register (MISR) to get */
	/* the V24 status signals. */

	status = usc_InReg( info, MISR );

	/* set serial signal bits to reflect MISR */

	if ( status & MISCSTATUS_CTS )
		info->serial_signals |= SerialSignal_CTS;

	if ( status & MISCSTATUS_DCD )
		info->serial_signals |= SerialSignal_DCD;

	if ( status & MISCSTATUS_RI )
		info->serial_signals |= SerialSignal_RI;

	if ( status & MISCSTATUS_DSR )
		info->serial_signals |= SerialSignal_DSR;

}	/* end of usc_get_serial_signals() */

/* usc_set_serial_signals()
 *
 *	Set the state of DTR and RTS based on contents of
 *	serial_signals member of device extension.
 *	
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void usc_set_serial_signals( struct mgsl_struct *info )
{
	u16 Control;
	unsigned char V24Out = info->serial_signals;

	/* get the current value of the Port Control Register (PCR) */

	Control = usc_InReg( info, PCR );

	if ( V24Out & SerialSignal_RTS )
		Control &= ~(BIT6);
	else
		Control |= BIT6;

	if ( V24Out & SerialSignal_DTR )
		Control &= ~(BIT4);
	else
		Control |= BIT4;

	usc_OutReg( info, PCR, Control );

}	/* end of usc_set_serial_signals() */

/* usc_enable_async_clock()
 *
 *	Enable the async clock at the specified frequency.
 *
 * Arguments:		info		pointer to device instance data
 *			data_rate	data rate of clock in bps
 *					0 disables the AUX clock.
 * Return Value:	None
 */
static void usc_enable_async_clock( struct mgsl_struct *info, u32 data_rate )
{
	if ( data_rate )	{
		/*
		 * Clock mode Control Register (CMCR)
		 * 
		 * <15..14>     00      counter 1 Disabled
		 * <13..12>     00      counter 0 Disabled
		 * <11..10>     11      BRG1 Input is TxC Pin
		 * <9..8>       11      BRG0 Input is TxC Pin
		 * <7..6>       01      DPLL Input is BRG1 Output
		 * <5..3>       100     TxCLK comes from BRG0
		 * <2..0>       100     RxCLK comes from BRG0
		 *
		 * 0000 1111 0110 0100 = 0x0f64
		 */
		
		usc_OutReg( info, CMCR, 0x0f64 );


		/*
		 * Write 16-bit Time Constant for BRG0
		 * Time Constant = (ClkSpeed / data_rate) - 1
		 * ClkSpeed = 921600 (ISA), 691200 (PCI)
		 */

		if ( info->bus_type == MGSL_BUS_TYPE_PCI )
			usc_OutReg( info, TC0R, (u16)((691200/data_rate) - 1) );
		else
			usc_OutReg( info, TC0R, (u16)((921600/data_rate) - 1) );

		
		/*
		 * Hardware Configuration Register (HCR)
		 * Clear Bit 1, BRG0 mode = Continuous
		 * Set Bit 0 to enable BRG0.
		 */

		usc_OutReg( info, HCR,
			    (u16)((usc_InReg( info, HCR ) & ~BIT1) | BIT0) );


		/* Input/Output Control Reg, <2..0> = 100, Drive RxC pin with BRG0 */

		usc_OutReg( info, IOCR,
			    (u16)((usc_InReg(info, IOCR) & 0xfff8) | 0x0004) );
	} else {
		/* data rate == 0 so turn off BRG0 */
		usc_OutReg( info, HCR, (u16)(usc_InReg( info, HCR ) & ~BIT0) );
	}

}	/* end of usc_enable_async_clock() */

/*
 * Buffer Structures:
 *
 * Normal memory access uses virtual addresses that can make discontiguous
 * physical memory pages appear to be contiguous in the virtual address
 * space (the processors memory mapping handles the conversions).
 *
 * DMA transfers require physically contiguous memory. This is because
 * the DMA system controller and DMA bus masters deal with memory using
 * only physical addresses.
 *
 * This causes a problem under Windows NT when large DMA buffers are
 * needed. Fragmentation of the nonpaged pool prevents allocations of
 * physically contiguous buffers larger than the PAGE_SIZE.
 *
 * However the 16C32 supports Bus Master Scatter/Gather DMA which
 * allows DMA transfers to physically discontiguous buffers. Information
 * about each data transfer buffer is contained in a memory structure
 * called a 'buffer entry'. A list of buffer entries is maintained
 * to track and control the use of the data transfer buffers.
 *
 * To support this strategy we will allocate sufficient PAGE_SIZE
 * contiguous memory buffers to allow for the total required buffer
 * space.
 *
 * The 16C32 accesses the list of buffer entries using Bus Master
 * DMA. Control information is read from the buffer entries by the
 * 16C32 to control data transfers. status information is written to
 * the buffer entries by the 16C32 to indicate the status of completed
 * transfers.
 *
 * The CPU writes control information to the buffer entries to control
 * the 16C32 and reads status information from the buffer entries to
 * determine information about received and transmitted frames.
 *
 * Because the CPU and 16C32 (adapter) both need simultaneous access
 * to the buffer entries, the buffer entry memory is allocated with
 * HalAllocateCommonBuffer(). This restricts the size of the buffer
 * entry list to PAGE_SIZE.
 *
 * The actual data buffers on the other hand will only be accessed
 * by the CPU or the adapter but not by both simultaneously. This allows
 * Scatter/Gather packet based DMA procedures for using physically
 * discontiguous pages.
 */

/*
 * mgsl_reset_tx_dma_buffers()
 *
 * 	Set the count for all transmit buffers to 0 to indicate the
 * 	buffer is available for use and set the current buffer to the
 * 	first buffer. This effectively makes all buffers free and
 * 	discards any data in buffers.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_reset_tx_dma_buffers( struct mgsl_struct *info )
{
	unsigned int i;

	for ( i = 0; i < info->tx_buffer_count; i++ ) {
		*((unsigned long *)&(info->tx_buffer_list[i].count)) = 0;
	}

	info->current_tx_buffer = 0;
	info->start_tx_dma_buffer = 0;
	info->tx_dma_buffers_used = 0;

	info->get_tx_holding_index = 0;
	info->put_tx_holding_index = 0;
	info->tx_holding_count = 0;

}	/* end of mgsl_reset_tx_dma_buffers() */

/*
 * num_free_tx_dma_buffers()
 *
 * 	returns the number of free tx dma buffers available
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	number of free tx dma buffers
 */
static int num_free_tx_dma_buffers(struct mgsl_struct *info)
{
	return info->tx_buffer_count - info->tx_dma_buffers_used;
}

/*
 * mgsl_reset_rx_dma_buffers()
 * 
 * 	Set the count for all receive buffers to DMABUFFERSIZE
 * 	and set the current buffer to the first buffer. This effectively
 * 	makes all buffers free and discards any data in buffers.
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_reset_rx_dma_buffers( struct mgsl_struct *info )
{
	unsigned int i;

	for ( i = 0; i < info->rx_buffer_count; i++ ) {
		*((unsigned long *)&(info->rx_buffer_list[i].count)) = DMABUFFERSIZE;
//		info->rx_buffer_list[i].count = DMABUFFERSIZE;
//		info->rx_buffer_list[i].status = 0;
	}

	info->current_rx_buffer = 0;

}	/* end of mgsl_reset_rx_dma_buffers() */

/*
 * mgsl_free_rx_frame_buffers()
 * 
 * 	Free the receive buffers used by a received SDLC
 * 	frame such that the buffers can be reused.
 * 
 * Arguments:
 * 
 * 	info			pointer to device instance data
 * 	StartIndex		index of 1st receive buffer of frame
 * 	EndIndex		index of last receive buffer of frame
 * 
 * Return Value:	None
 */
static void mgsl_free_rx_frame_buffers( struct mgsl_struct *info, unsigned int StartIndex, unsigned int EndIndex )
{
	bool Done = false;
	DMABUFFERENTRY *pBufEntry;
	unsigned int Index;

	/* Starting with 1st buffer entry of the frame clear the status */
	/* field and set the count field to DMA Buffer Size. */

	Index = StartIndex;

	while( !Done ) {
		pBufEntry = &(info->rx_buffer_list[Index]);

		if ( Index == EndIndex ) {
			/* This is the last buffer of the frame! */
			Done = true;
		}

		/* reset current buffer for reuse */
//		pBufEntry->status = 0;
//		pBufEntry->count = DMABUFFERSIZE;
		*((unsigned long *)&(pBufEntry->count)) = DMABUFFERSIZE;

		/* advance to next buffer entry in linked list */
		Index++;
		if ( Index == info->rx_buffer_count )
			Index = 0;
	}

	/* set current buffer to next buffer after last buffer of frame */
	info->current_rx_buffer = Index;

}	/* end of free_rx_frame_buffers() */

/* mgsl_get_rx_frame()
 * 
 * 	This function attempts to return a received SDLC frame from the
 * 	receive DMA buffers. Only frames received without errors are returned.
 *
 * Arguments:	 	info	pointer to device extension
 * Return Value:	true if frame returned, otherwise false
 */
static bool mgsl_get_rx_frame(struct mgsl_struct *info)
{
	unsigned int StartIndex, EndIndex;	/* index of 1st and last buffers of Rx frame */
	unsigned short status;
	DMABUFFERENTRY *pBufEntry;
	unsigned int framesize = 0;
	bool ReturnCode = false;
	unsigned long flags;
	struct tty_struct *tty = info->port.tty;
	bool return_frame = false;
	
	/*
	 * current_rx_buffer points to the 1st buffer of the next available
	 * receive frame. To find the last buffer of the frame look for
	 * a non-zero status field in the buffer entries. (The status
	 * field is set by the 16C32 after completing a receive frame.
	 */

	StartIndex = EndIndex = info->current_rx_buffer;

	while( !info->rx_buffer_list[EndIndex].status ) {
		/*
		 * If the count field of the buffer entry is non-zero then
		 * this buffer has not been used. (The 16C32 clears the count
		 * field when it starts using the buffer.) If an unused buffer
		 * is encountered then there are no frames available.
		 */

		if ( info->rx_buffer_list[EndIndex].count )
			goto Cleanup;

		/* advance to next buffer entry in linked list */
		EndIndex++;
		if ( EndIndex == info->rx_buffer_count )
			EndIndex = 0;

		/* if entire list searched then no frame available */
		if ( EndIndex == StartIndex ) {
			/* If this occurs then something bad happened,
			 * all buffers have been 'used' but none mark
			 * the end of a frame. Reset buffers and receiver.
			 */

			if ( info->rx_enabled ){
				spin_lock_irqsave(&info->irq_spinlock,flags);
				usc_start_receiver(info);
				spin_unlock_irqrestore(&info->irq_spinlock,flags);
			}
			goto Cleanup;
		}
	}


	/* check status of receive frame */
	
	status = info->rx_buffer_list[EndIndex].status;

	if ( status & (RXSTATUS_SHORT_FRAME + RXSTATUS_OVERRUN +
			RXSTATUS_CRC_ERROR + RXSTATUS_ABORT) ) {
		if ( status & RXSTATUS_SHORT_FRAME )
			info->icount.rxshort++;
		else if ( status & RXSTATUS_ABORT )
			info->icount.rxabort++;
		else if ( status & RXSTATUS_OVERRUN )
			info->icount.rxover++;
		else {
			info->icount.rxcrc++;
			if ( info->params.crc_type & HDLC_CRC_RETURN_EX )
				return_frame = true;
		}
		framesize = 0;
#if SYNCLINK_GENERIC_HDLC
		{
			info->netdev->stats.rx_errors++;
			info->netdev->stats.rx_frame_errors++;
		}
#endif
	} else
		return_frame = true;

	if ( return_frame ) {
		/* receive frame has no errors, get frame size.
		 * The frame size is the starting value of the RCC (which was
		 * set to 0xffff) minus the ending value of the RCC (decremented
		 * once for each receive character) minus 2 for the 16-bit CRC.
		 */

		framesize = RCLRVALUE - info->rx_buffer_list[EndIndex].rcc;

		/* adjust frame size for CRC if any */
		if ( info->params.crc_type == HDLC_CRC_16_CCITT )
			framesize -= 2;
		else if ( info->params.crc_type == HDLC_CRC_32_CCITT )
			framesize -= 4;		
	}

	if ( debug_level >= DEBUG_LEVEL_BH )
		printk("%s(%d):mgsl_get_rx_frame(%s) status=%04X size=%d\n",
			__FILE__,__LINE__,info->device_name,status,framesize);
			
	if ( debug_level >= DEBUG_LEVEL_DATA )
		mgsl_trace_block(info,info->rx_buffer_list[StartIndex].virt_addr,
			min_t(int, framesize, DMABUFFERSIZE),0);
		
	if (framesize) {
		if ( ( (info->params.crc_type & HDLC_CRC_RETURN_EX) &&
				((framesize+1) > info->max_frame_size) ) ||
			(framesize > info->max_frame_size) )
			info->icount.rxlong++;
		else {
			/* copy dma buffer(s) to contiguous intermediate buffer */
			int copy_count = framesize;
			int index = StartIndex;
			unsigned char *ptmp = info->intermediate_rxbuffer;

			if ( !(status & RXSTATUS_CRC_ERROR))
			info->icount.rxok++;
			
			while(copy_count) {
				int partial_count;
				if ( copy_count > DMABUFFERSIZE )
					partial_count = DMABUFFERSIZE;
				else
					partial_count = copy_count;
			
				pBufEntry = &(info->rx_buffer_list[index]);
				memcpy( ptmp, pBufEntry->virt_addr, partial_count );
				ptmp += partial_count;
				copy_count -= partial_count;
				
				if ( ++index == info->rx_buffer_count )
					index = 0;
			}

			if ( info->params.crc_type & HDLC_CRC_RETURN_EX ) {
				++framesize;
				*ptmp = (status & RXSTATUS_CRC_ERROR ?
						RX_CRC_ERROR :
						RX_OK);

				if ( debug_level >= DEBUG_LEVEL_DATA )
					printk("%s(%d):mgsl_get_rx_frame(%s) rx frame status=%d\n",
						__FILE__,__LINE__,info->device_name,
						*ptmp);
			}

#if SYNCLINK_GENERIC_HDLC
			if (info->netcount)
				hdlcdev_rx(info,info->intermediate_rxbuffer,framesize);
			else
#endif
				ldisc_receive_buf(tty, info->intermediate_rxbuffer, info->flag_buf, framesize);
		}
	}
	/* Free the buffers used by this frame. */
	mgsl_free_rx_frame_buffers( info, StartIndex, EndIndex );

	ReturnCode = true;

Cleanup:

	if ( info->rx_enabled && info->rx_overflow ) {
		/* The receiver needs to restarted because of 
		 * a receive overflow (buffer or FIFO). If the 
		 * receive buffers are now empty, then restart receiver.
		 */

		if ( !info->rx_buffer_list[EndIndex].status &&
			info->rx_buffer_list[EndIndex].count ) {
			spin_lock_irqsave(&info->irq_spinlock,flags);
			usc_start_receiver(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
		}
	}

	return ReturnCode;

}	/* end of mgsl_get_rx_frame() */

/* mgsl_get_raw_rx_frame()
 *
 *     	This function attempts to return a received frame from the
 *	receive DMA buffers when running in external loop mode. In this mode,
 *	we will return at most one DMABUFFERSIZE frame to the application.
 *	The USC receiver is triggering off of DCD going active to start a new
 *	frame, and DCD going inactive to terminate the frame (similar to
 *	processing a closing flag character).
 *
 *	In this routine, we will return DMABUFFERSIZE "chunks" at a time.
 *	If DCD goes inactive, the last Rx DMA Buffer will have a non-zero
 * 	status field and the RCC field will indicate the length of the
 *	entire received frame. We take this RCC field and get the modulus
 *	of RCC and DMABUFFERSIZE to determine if number of bytes in the
 *	last Rx DMA buffer and return that last portion of the frame.
 *
 * Arguments:	 	info	pointer to device extension
 * Return Value:	true if frame returned, otherwise false
 */
static bool mgsl_get_raw_rx_frame(struct mgsl_struct *info)
{
	unsigned int CurrentIndex, NextIndex;
	unsigned short status;
	DMABUFFERENTRY *pBufEntry;
	unsigned int framesize = 0;
	bool ReturnCode = false;
	unsigned long flags;
	struct tty_struct *tty = info->port.tty;

	/*
 	 * current_rx_buffer points to the 1st buffer of the next available
	 * receive frame. The status field is set by the 16C32 after
	 * completing a receive frame. If the status field of this buffer
	 * is zero, either the USC is still filling this buffer or this
	 * is one of a series of buffers making up a received frame.
	 *
	 * If the count field of this buffer is zero, the USC is either
	 * using this buffer or has used this buffer. Look at the count
	 * field of the next buffer. If that next buffer's count is
	 * non-zero, the USC is still actively using the current buffer.
	 * Otherwise, if the next buffer's count field is zero, the
	 * current buffer is complete and the USC is using the next
	 * buffer.
	 */
	CurrentIndex = NextIndex = info->current_rx_buffer;
	++NextIndex;
	if ( NextIndex == info->rx_buffer_count )
		NextIndex = 0;

	if ( info->rx_buffer_list[CurrentIndex].status != 0 ||
		(info->rx_buffer_list[CurrentIndex].count == 0 &&
			info->rx_buffer_list[NextIndex].count == 0)) {
		/*
	 	 * Either the status field of this dma buffer is non-zero
		 * (indicating the last buffer of a receive frame) or the next
	 	 * buffer is marked as in use -- implying this buffer is complete
		 * and an intermediate buffer for this received frame.
	 	 */

		status = info->rx_buffer_list[CurrentIndex].status;

		if ( status & (RXSTATUS_SHORT_FRAME + RXSTATUS_OVERRUN +
				RXSTATUS_CRC_ERROR + RXSTATUS_ABORT) ) {
			if ( status & RXSTATUS_SHORT_FRAME )
				info->icount.rxshort++;
			else if ( status & RXSTATUS_ABORT )
				info->icount.rxabort++;
			else if ( status & RXSTATUS_OVERRUN )
				info->icount.rxover++;
			else
				info->icount.rxcrc++;
			framesize = 0;
		} else {
			/*
			 * A receive frame is available, get frame size and status.
			 *
			 * The frame size is the starting value of the RCC (which was
			 * set to 0xffff) minus the ending value of the RCC (decremented
			 * once for each receive character) minus 2 or 4 for the 16-bit
			 * or 32-bit CRC.
			 *
			 * If the status field is zero, this is an intermediate buffer.
			 * It's size is 4K.
			 *
			 * If the DMA Buffer Entry's Status field is non-zero, the
			 * receive operation completed normally (ie: DCD dropped). The
			 * RCC field is valid and holds the received frame size.
			 * It is possible that the RCC field will be zero on a DMA buffer
			 * entry with a non-zero status. This can occur if the total
			 * frame size (number of bytes between the time DCD goes active
			 * to the time DCD goes inactive) exceeds 65535 bytes. In this
			 * case the 16C32 has underrun on the RCC count and appears to
			 * stop updating this counter to let us know the actual received
			 * frame size. If this happens (non-zero status and zero RCC),
			 * simply return the entire RxDMA Buffer
			 */
			if ( status ) {
				/*
				 * In the event that the final RxDMA Buffer is
				 * terminated with a non-zero status and the RCC
				 * field is zero, we interpret this as the RCC
				 * having underflowed (received frame > 65535 bytes).
				 *
				 * Signal the event to the user by passing back
				 * a status of RxStatus_CrcError returning the full
				 * buffer and let the app figure out what data is
				 * actually valid
				 */
				if ( info->rx_buffer_list[CurrentIndex].rcc )
					framesize = RCLRVALUE - info->rx_buffer_list[CurrentIndex].rcc;
				else
					framesize = DMABUFFERSIZE;
			}
			else
				framesize = DMABUFFERSIZE;
		}

		if ( framesize > DMABUFFERSIZE ) {
			/*
			 * if running in raw sync mode, ISR handler for
			 * End Of Buffer events terminates all buffers at 4K.
			 * If this frame size is said to be >4K, get the
			 * actual number of bytes of the frame in this buffer.
			 */
			framesize = framesize % DMABUFFERSIZE;
		}


		if ( debug_level >= DEBUG_LEVEL_BH )
			printk("%s(%d):mgsl_get_raw_rx_frame(%s) status=%04X size=%d\n",
				__FILE__,__LINE__,info->device_name,status,framesize);

		if ( debug_level >= DEBUG_LEVEL_DATA )
			mgsl_trace_block(info,info->rx_buffer_list[CurrentIndex].virt_addr,
				min_t(int, framesize, DMABUFFERSIZE),0);

		if (framesize) {
			/* copy dma buffer(s) to contiguous intermediate buffer */
			/* NOTE: we never copy more than DMABUFFERSIZE bytes	*/

			pBufEntry = &(info->rx_buffer_list[CurrentIndex]);
			memcpy( info->intermediate_rxbuffer, pBufEntry->virt_addr, framesize);
			info->icount.rxok++;

			ldisc_receive_buf(tty, info->intermediate_rxbuffer, info->flag_buf, framesize);
		}

		/* Free the buffers used by this frame. */
		mgsl_free_rx_frame_buffers( info, CurrentIndex, CurrentIndex );

		ReturnCode = true;
	}


	if ( info->rx_enabled && info->rx_overflow ) {
		/* The receiver needs to restarted because of
		 * a receive overflow (buffer or FIFO). If the
		 * receive buffers are now empty, then restart receiver.
		 */

		if ( !info->rx_buffer_list[CurrentIndex].status &&
			info->rx_buffer_list[CurrentIndex].count ) {
			spin_lock_irqsave(&info->irq_spinlock,flags);
			usc_start_receiver(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
		}
	}

	return ReturnCode;

}	/* end of mgsl_get_raw_rx_frame() */

/* mgsl_load_tx_dma_buffer()
 * 
 * 	Load the transmit DMA buffer with the specified data.
 * 
 * Arguments:
 * 
 * 	info		pointer to device extension
 * 	Buffer		pointer to buffer containing frame to load
 * 	BufferSize	size in bytes of frame in Buffer
 * 
 * Return Value: 	None
 */
static void mgsl_load_tx_dma_buffer(struct mgsl_struct *info,
		const char *Buffer, unsigned int BufferSize)
{
	unsigned short Copycount;
	unsigned int i = 0;
	DMABUFFERENTRY *pBufEntry;
	
	if ( debug_level >= DEBUG_LEVEL_DATA )
		mgsl_trace_block(info,Buffer, min_t(int, BufferSize, DMABUFFERSIZE), 1);

	if (info->params.flags & HDLC_FLAG_HDLC_LOOPMODE) {
		/* set CMR:13 to start transmit when
		 * next GoAhead (abort) is received
		 */
	 	info->cmr_value |= BIT13;			  
	}
		
	/* begin loading the frame in the next available tx dma
	 * buffer, remember it's starting location for setting
	 * up tx dma operation
	 */
	i = info->current_tx_buffer;
	info->start_tx_dma_buffer = i;

	/* Setup the status and RCC (Frame Size) fields of the 1st */
	/* buffer entry in the transmit DMA buffer list. */

	info->tx_buffer_list[i].status = info->cmr_value & 0xf000;
	info->tx_buffer_list[i].rcc    = BufferSize;
	info->tx_buffer_list[i].count  = BufferSize;

	/* Copy frame data from 1st source buffer to the DMA buffers. */
	/* The frame data may span multiple DMA buffers. */

	while( BufferSize ){
		/* Get a pointer to next DMA buffer entry. */
		pBufEntry = &info->tx_buffer_list[i++];
			
		if ( i == info->tx_buffer_count )
			i=0;

		/* Calculate the number of bytes that can be copied from */
		/* the source buffer to this DMA buffer. */
		if ( BufferSize > DMABUFFERSIZE )
			Copycount = DMABUFFERSIZE;
		else
			Copycount = BufferSize;

		/* Actually copy data from source buffer to DMA buffer. */
		/* Also set the data count for this individual DMA buffer. */
		if ( info->bus_type == MGSL_BUS_TYPE_PCI )
			mgsl_load_pci_memory(pBufEntry->virt_addr, Buffer,Copycount);
		else
			memcpy(pBufEntry->virt_addr, Buffer, Copycount);

		pBufEntry->count = Copycount;

		/* Advance source pointer and reduce remaining data count. */
		Buffer += Copycount;
		BufferSize -= Copycount;

		++info->tx_dma_buffers_used;
	}

	/* remember next available tx dma buffer */
	info->current_tx_buffer = i;

}	/* end of mgsl_load_tx_dma_buffer() */

/*
 * mgsl_register_test()
 * 
 * 	Performs a register test of the 16C32.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:		true if test passed, otherwise false
 */
static bool mgsl_register_test( struct mgsl_struct *info )
{
	static unsigned short BitPatterns[] =
		{ 0x0000, 0xffff, 0xaaaa, 0x5555, 0x1234, 0x6969, 0x9696, 0x0f0f };
	static unsigned int Patterncount = ARRAY_SIZE(BitPatterns);
	unsigned int i;
	bool rc = true;
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_reset(info);

	/* Verify the reset state of some registers. */

	if ( (usc_InReg( info, SICR ) != 0) ||
		  (usc_InReg( info, IVR  ) != 0) ||
		  (usc_InDmaReg( info, DIVR ) != 0) ){
		rc = false;
	}

	if ( rc ){
		/* Write bit patterns to various registers but do it out of */
		/* sync, then read back and verify values. */

		for ( i = 0 ; i < Patterncount ; i++ ) {
			usc_OutReg( info, TC0R, BitPatterns[i] );
			usc_OutReg( info, TC1R, BitPatterns[(i+1)%Patterncount] );
			usc_OutReg( info, TCLR, BitPatterns[(i+2)%Patterncount] );
			usc_OutReg( info, RCLR, BitPatterns[(i+3)%Patterncount] );
			usc_OutReg( info, RSR,  BitPatterns[(i+4)%Patterncount] );
			usc_OutDmaReg( info, TBCR, BitPatterns[(i+5)%Patterncount] );

			if ( (usc_InReg( info, TC0R ) != BitPatterns[i]) ||
				  (usc_InReg( info, TC1R ) != BitPatterns[(i+1)%Patterncount]) ||
				  (usc_InReg( info, TCLR ) != BitPatterns[(i+2)%Patterncount]) ||
				  (usc_InReg( info, RCLR ) != BitPatterns[(i+3)%Patterncount]) ||
				  (usc_InReg( info, RSR )  != BitPatterns[(i+4)%Patterncount]) ||
				  (usc_InDmaReg( info, TBCR ) != BitPatterns[(i+5)%Patterncount]) ){
				rc = false;
				break;
			}
		}
	}

	usc_reset(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	return rc;

}	/* end of mgsl_register_test() */

/* mgsl_irq_test() 	Perform interrupt test of the 16C32.
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	true if test passed, otherwise false
 */
static bool mgsl_irq_test( struct mgsl_struct *info )
{
	unsigned long EndTime;
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_reset(info);

	/*
	 * Setup 16C32 to interrupt on TxC pin (14MHz clock) transition. 
	 * The ISR sets irq_occurred to true.
	 */

	info->irq_occurred = false;

	/* Enable INTEN gate for ISA adapter (Port 6, Bit12) */
	/* Enable INTEN (Port 6, Bit12) */
	/* This connects the IRQ request signal to the ISA bus */
	/* on the ISA adapter. This has no effect for the PCI adapter */
	usc_OutReg( info, PCR, (unsigned short)((usc_InReg(info, PCR) | BIT13) & ~BIT12) );

	usc_EnableMasterIrqBit(info);
	usc_EnableInterrupts(info, IO_PIN);
	usc_ClearIrqPendingBits(info, IO_PIN);
	
	usc_UnlatchIostatusBits(info, MISCSTATUS_TXC_LATCHED);
	usc_EnableStatusIrqs(info, SICR_TXC_ACTIVE + SICR_TXC_INACTIVE);

	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	EndTime=100;
	while( EndTime-- && !info->irq_occurred ) {
		msleep_interruptible(10);
	}
	
	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_reset(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
	return info->irq_occurred;

}	/* end of mgsl_irq_test() */

/* mgsl_dma_test()
 * 
 * 	Perform a DMA test of the 16C32. A small frame is
 * 	transmitted via DMA from a transmit buffer to a receive buffer
 * 	using single buffer DMA mode.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	true if test passed, otherwise false
 */
static bool mgsl_dma_test( struct mgsl_struct *info )
{
	unsigned short FifoLevel;
	unsigned long phys_addr;
	unsigned int FrameSize;
	unsigned int i;
	char *TmpPtr;
	bool rc = true;
	unsigned short status=0;
	unsigned long EndTime;
	unsigned long flags;
	MGSL_PARAMS tmp_params;

	/* save current port options */
	memcpy(&tmp_params,&info->params,sizeof(MGSL_PARAMS));
	/* load default port options */
	memcpy(&info->params,&default_params,sizeof(MGSL_PARAMS));
	
#define TESTFRAMESIZE 40

	spin_lock_irqsave(&info->irq_spinlock,flags);
	
	/* setup 16C32 for SDLC DMA transfer mode */

	usc_reset(info);
	usc_set_sdlc_mode(info);
	usc_enable_loopback(info,1);
	
	/* Reprogram the RDMR so that the 16C32 does NOT clear the count
	 * field of the buffer entry after fetching buffer address. This
	 * way we can detect a DMA failure for a DMA read (which should be
	 * non-destructive to system memory) before we try and write to
	 * memory (where a failure could corrupt system memory).
	 */

	/* Receive DMA mode Register (RDMR)
	 * 
	 * <15..14>	11	DMA mode = Linked List Buffer mode
	 * <13>		1	RSBinA/L = store Rx status Block in List entry
	 * <12>		0	1 = Clear count of List Entry after fetching
	 * <11..10>	00	Address mode = Increment
	 * <9>		1	Terminate Buffer on RxBound
	 * <8>		0	Bus Width = 16bits
	 * <7..0>		?	status Bits (write as 0s)
	 * 
	 * 1110 0010 0000 0000 = 0xe200
	 */

	usc_OutDmaReg( info, RDMR, 0xe200 );
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);


	/* SETUP TRANSMIT AND RECEIVE DMA BUFFERS */

	FrameSize = TESTFRAMESIZE;

	/* setup 1st transmit buffer entry: */
	/* with frame size and transmit control word */

	info->tx_buffer_list[0].count  = FrameSize;
	info->tx_buffer_list[0].rcc    = FrameSize;
	info->tx_buffer_list[0].status = 0x4000;

	/* build a transmit frame in 1st transmit DMA buffer */

	TmpPtr = info->tx_buffer_list[0].virt_addr;
	for (i = 0; i < FrameSize; i++ )
		*TmpPtr++ = i;

	/* setup 1st receive buffer entry: */
	/* clear status, set max receive buffer size */

	info->rx_buffer_list[0].status = 0;
	info->rx_buffer_list[0].count = FrameSize + 4;

	/* zero out the 1st receive buffer */

	memset( info->rx_buffer_list[0].virt_addr, 0, FrameSize + 4 );

	/* Set count field of next buffer entries to prevent */
	/* 16C32 from using buffers after the 1st one. */

	info->tx_buffer_list[1].count = 0;
	info->rx_buffer_list[1].count = 0;
	

	/***************************/
	/* Program 16C32 receiver. */
	/***************************/
	
	spin_lock_irqsave(&info->irq_spinlock,flags);

	/* setup DMA transfers */
	usc_RTCmd( info, RTCmd_PurgeRxFifo );

	/* program 16C32 receiver with physical address of 1st DMA buffer entry */
	phys_addr = info->rx_buffer_list[0].phys_entry;
	usc_OutDmaReg( info, NRARL, (unsigned short)phys_addr );
	usc_OutDmaReg( info, NRARU, (unsigned short)(phys_addr >> 16) );

	/* Clear the Rx DMA status bits (read RDMR) and start channel */
	usc_InDmaReg( info, RDMR );
	usc_DmaCmd( info, DmaCmd_InitRxChannel );

	/* Enable Receiver (RMR <1..0> = 10) */
	usc_OutReg( info, RMR, (unsigned short)((usc_InReg(info, RMR) & 0xfffc) | 0x0002) );
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);


	/*************************************************************/
	/* WAIT FOR RECEIVER TO DMA ALL PARAMETERS FROM BUFFER ENTRY */
	/*************************************************************/

	/* Wait 100ms for interrupt. */
	EndTime = jiffies + msecs_to_jiffies(100);

	for(;;) {
		if (time_after(jiffies, EndTime)) {
			rc = false;
			break;
		}

		spin_lock_irqsave(&info->irq_spinlock,flags);
		status = usc_InDmaReg( info, RDMR );
		spin_unlock_irqrestore(&info->irq_spinlock,flags);

		if ( !(status & BIT4) && (status & BIT5) ) {
			/* INITG (BIT 4) is inactive (no entry read in progress) AND */
			/* BUSY  (BIT 5) is active (channel still active). */
			/* This means the buffer entry read has completed. */
			break;
		}
	}


	/******************************/
	/* Program 16C32 transmitter. */
	/******************************/
	
	spin_lock_irqsave(&info->irq_spinlock,flags);

	/* Program the Transmit Character Length Register (TCLR) */
	/* and clear FIFO (TCC is loaded with TCLR on FIFO clear) */

	usc_OutReg( info, TCLR, (unsigned short)info->tx_buffer_list[0].count );
	usc_RTCmd( info, RTCmd_PurgeTxFifo );

	/* Program the address of the 1st DMA Buffer Entry in linked list */

	phys_addr = info->tx_buffer_list[0].phys_entry;
	usc_OutDmaReg( info, NTARL, (unsigned short)phys_addr );
	usc_OutDmaReg( info, NTARU, (unsigned short)(phys_addr >> 16) );

	/* unlatch Tx status bits, and start transmit channel. */

	usc_OutReg( info, TCSR, (unsigned short)(( usc_InReg(info, TCSR) & 0x0f00) | 0xfa) );
	usc_DmaCmd( info, DmaCmd_InitTxChannel );

	/* wait for DMA controller to fill transmit FIFO */

	usc_TCmd( info, TCmd_SelectTicrTxFifostatus );
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);


	/**********************************/
	/* WAIT FOR TRANSMIT FIFO TO FILL */
	/**********************************/
	
	/* Wait 100ms */
	EndTime = jiffies + msecs_to_jiffies(100);

	for(;;) {
		if (time_after(jiffies, EndTime)) {
			rc = false;
			break;
		}

		spin_lock_irqsave(&info->irq_spinlock,flags);
		FifoLevel = usc_InReg(info, TICR) >> 8;
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
			
		if ( FifoLevel < 16 )
			break;
		else
			if ( FrameSize < 32 ) {
				/* This frame is smaller than the entire transmit FIFO */
				/* so wait for the entire frame to be loaded. */
				if ( FifoLevel <= (32 - FrameSize) )
					break;
			}
	}


	if ( rc )
	{
		/* Enable 16C32 transmitter. */

		spin_lock_irqsave(&info->irq_spinlock,flags);
		
		/* Transmit mode Register (TMR), <1..0> = 10, Enable Transmitter */
		usc_TCmd( info, TCmd_SendFrame );
		usc_OutReg( info, TMR, (unsigned short)((usc_InReg(info, TMR) & 0xfffc) | 0x0002) );
		
		spin_unlock_irqrestore(&info->irq_spinlock,flags);

						
		/******************************/
		/* WAIT FOR TRANSMIT COMPLETE */
		/******************************/

		/* Wait 100ms */
		EndTime = jiffies + msecs_to_jiffies(100);

		/* While timer not expired wait for transmit complete */

		spin_lock_irqsave(&info->irq_spinlock,flags);
		status = usc_InReg( info, TCSR );
		spin_unlock_irqrestore(&info->irq_spinlock,flags);

		while ( !(status & (BIT6+BIT5+BIT4+BIT2+BIT1)) ) {
			if (time_after(jiffies, EndTime)) {
				rc = false;
				break;
			}

			spin_lock_irqsave(&info->irq_spinlock,flags);
			status = usc_InReg( info, TCSR );
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
		}
	}


	if ( rc ){
		/* CHECK FOR TRANSMIT ERRORS */
		if ( status & (BIT5 + BIT1) ) 
			rc = false;
	}

	if ( rc ) {
		/* WAIT FOR RECEIVE COMPLETE */

		/* Wait 100ms */
		EndTime = jiffies + msecs_to_jiffies(100);

		/* Wait for 16C32 to write receive status to buffer entry. */
		status=info->rx_buffer_list[0].status;
		while ( status == 0 ) {
			if (time_after(jiffies, EndTime)) {
				rc = false;
				break;
			}
			status=info->rx_buffer_list[0].status;
		}
	}


	if ( rc ) {
		/* CHECK FOR RECEIVE ERRORS */
		status = info->rx_buffer_list[0].status;

		if ( status & (BIT8 + BIT3 + BIT1) ) {
			/* receive error has occurred */
			rc = false;
		} else {
			if ( memcmp( info->tx_buffer_list[0].virt_addr ,
				info->rx_buffer_list[0].virt_addr, FrameSize ) ){
				rc = false;
			}
		}
	}

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_reset( info );
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	/* restore current port options */
	memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
	
	return rc;

}	/* end of mgsl_dma_test() */

/* mgsl_adapter_test()
 * 
 * 	Perform the register, IRQ, and DMA tests for the 16C32.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	0 if success, otherwise -ENODEV
 */
static int mgsl_adapter_test( struct mgsl_struct *info )
{
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):Testing device %s\n",
			__FILE__,__LINE__,info->device_name );
			
	if ( !mgsl_register_test( info ) ) {
		info->init_error = DiagStatus_AddressFailure;
		printk( "%s(%d):Register test failure for device %s Addr=%04X\n",
			__FILE__,__LINE__,info->device_name, (unsigned short)(info->io_base) );
		return -ENODEV;
	}

	if ( !mgsl_irq_test( info ) ) {
		info->init_error = DiagStatus_IrqFailure;
		printk( "%s(%d):Interrupt test failure for device %s IRQ=%d\n",
			__FILE__,__LINE__,info->device_name, (unsigned short)(info->irq_level) );
		return -ENODEV;
	}

	if ( !mgsl_dma_test( info ) ) {
		info->init_error = DiagStatus_DmaFailure;
		printk( "%s(%d):DMA test failure for device %s DMA=%d\n",
			__FILE__,__LINE__,info->device_name, (unsigned short)(info->dma_level) );
		return -ENODEV;
	}

	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):device %s passed diagnostics\n",
			__FILE__,__LINE__,info->device_name );
			
	return 0;

}	/* end of mgsl_adapter_test() */

/* mgsl_memory_test()
 * 
 * 	Test the shared memory on a PCI adapter.
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	true if test passed, otherwise false
 */
static bool mgsl_memory_test( struct mgsl_struct *info )
{
	static unsigned long BitPatterns[] =
		{ 0x0, 0x55555555, 0xaaaaaaaa, 0x66666666, 0x99999999, 0xffffffff, 0x12345678 };
	unsigned long Patterncount = ARRAY_SIZE(BitPatterns);
	unsigned long i;
	unsigned long TestLimit = SHARED_MEM_ADDRESS_SIZE/sizeof(unsigned long);
	unsigned long * TestAddr;

	if ( info->bus_type != MGSL_BUS_TYPE_PCI )
		return true;

	TestAddr = (unsigned long *)info->memory_base;

	/* Test data lines with test pattern at one location. */

	for ( i = 0 ; i < Patterncount ; i++ ) {
		*TestAddr = BitPatterns[i];
		if ( *TestAddr != BitPatterns[i] )
			return false;
	}

	/* Test address lines with incrementing pattern over */
	/* entire address range. */

	for ( i = 0 ; i < TestLimit ; i++ ) {
		*TestAddr = i * 4;
		TestAddr++;
	}

	TestAddr = (unsigned long *)info->memory_base;

	for ( i = 0 ; i < TestLimit ; i++ ) {
		if ( *TestAddr != i * 4 )
			return false;
		TestAddr++;
	}

	memset( info->memory_base, 0, SHARED_MEM_ADDRESS_SIZE );

	return true;

}	/* End Of mgsl_memory_test() */


/* mgsl_load_pci_memory()
 * 
 * 	Load a large block of data into the PCI shared memory.
 * 	Use this instead of memcpy() or memmove() to move data
 * 	into the PCI shared memory.
 * 
 * Notes:
 * 
 * 	This function prevents the PCI9050 interface chip from hogging
 * 	the adapter local bus, which can starve the 16C32 by preventing
 * 	16C32 bus master cycles.
 * 
 * 	The PCI9050 documentation says that the 9050 will always release
 * 	control of the local bus after completing the current read
 * 	or write operation.
 * 
 * 	It appears that as long as the PCI9050 write FIFO is full, the
 * 	PCI9050 treats all of the writes as a single burst transaction
 * 	and will not release the bus. This causes DMA latency problems
 * 	at high speeds when copying large data blocks to the shared
 * 	memory.
 * 
 * 	This function in effect, breaks the a large shared memory write
 * 	into multiple transations by interleaving a shared memory read
 * 	which will flush the write FIFO and 'complete' the write
 * 	transation. This allows any pending DMA request to gain control
 * 	of the local bus in a timely fasion.
 * 
 * Arguments:
 * 
 * 	TargetPtr	pointer to target address in PCI shared memory
 * 	SourcePtr	pointer to source buffer for data
 * 	count		count in bytes of data to copy
 *
 * Return Value:	None
 */
static void mgsl_load_pci_memory( char* TargetPtr, const char* SourcePtr,
	unsigned short count )
{
	/* 16 32-bit writes @ 60ns each = 960ns max latency on local bus */
#define PCI_LOAD_INTERVAL 64

	unsigned short Intervalcount = count / PCI_LOAD_INTERVAL;
	unsigned short Index;
	unsigned long Dummy;

	for ( Index = 0 ; Index < Intervalcount ; Index++ )
	{
		memcpy(TargetPtr, SourcePtr, PCI_LOAD_INTERVAL);
		Dummy = *((volatile unsigned long *)TargetPtr);
		TargetPtr += PCI_LOAD_INTERVAL;
		SourcePtr += PCI_LOAD_INTERVAL;
	}

	memcpy( TargetPtr, SourcePtr, count % PCI_LOAD_INTERVAL );

}	/* End Of mgsl_load_pci_memory() */

static void mgsl_trace_block(struct mgsl_struct *info,const char* data, int count, int xmit)
{
	int i;
	int linecount;
	if (xmit)
		printk("%s tx data:\n",info->device_name);
	else
		printk("%s rx data:\n",info->device_name);
		
	while(count) {
		if (count > 16)
			linecount = 16;
		else
			linecount = count;
			
		for(i=0;i<linecount;i++)
			printk("%02X ",(unsigned char)data[i]);
		for(;i<17;i++)
			printk("   ");
		for(i=0;i<linecount;i++) {
			if (data[i]>=040 && data[i]<=0176)
				printk("%c",data[i]);
			else
				printk(".");
		}
		printk("\n");
		
		data  += linecount;
		count -= linecount;
	}
}	/* end of mgsl_trace_block() */

/* mgsl_tx_timeout()
 * 
 * 	called when HDLC frame times out
 * 	update stats and do tx completion processing
 * 	
 * Arguments:	context		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_tx_timeout(unsigned long context)
{
	struct mgsl_struct *info = (struct mgsl_struct*)context;
	unsigned long flags;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_tx_timeout(%s)\n",
			__FILE__,__LINE__,info->device_name);
	if(info->tx_active &&
	   (info->params.mode == MGSL_MODE_HDLC ||
	    info->params.mode == MGSL_MODE_RAW) ) {
		info->icount.txtimeout++;
	}
	spin_lock_irqsave(&info->irq_spinlock,flags);
	info->tx_active = false;
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

	if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
		usc_loopmode_cancel_transmit( info );

	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
#if SYNCLINK_GENERIC_HDLC
	if (info->netcount)
		hdlcdev_tx_done(info);
	else
#endif
		mgsl_bh_transmit(info);
	
}	/* end of mgsl_tx_timeout() */

/* signal that there are no more frames to send, so that
 * line is 'released' by echoing RxD to TxD when current
 * transmission is complete (or immediately if no tx in progress).
 */
static int mgsl_loopmode_send_done( struct mgsl_struct * info )
{
	unsigned long flags;
	
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (info->params.flags & HDLC_FLAG_HDLC_LOOPMODE) {
		if (info->tx_active)
			info->loopmode_send_done_requested = true;
		else
			usc_loopmode_send_done(info);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	return 0;
}

/* release the line by echoing RxD to TxD
 * upon completion of a transmit frame
 */
static void usc_loopmode_send_done( struct mgsl_struct * info )
{
 	info->loopmode_send_done_requested = false;
 	/* clear CMR:13 to 0 to start echoing RxData to TxData */
 	info->cmr_value &= ~BIT13;			  
 	usc_OutReg(info, CMR, info->cmr_value);
}

/* abort a transmit in progress while in HDLC LoopMode
 */
static void usc_loopmode_cancel_transmit( struct mgsl_struct * info )
{
 	/* reset tx dma channel and purge TxFifo */
 	usc_RTCmd( info, RTCmd_PurgeTxFifo );
 	usc_DmaCmd( info, DmaCmd_ResetTxChannel );
  	usc_loopmode_send_done( info );
}

/* for HDLC/SDLC LoopMode, setting CMR:13 after the transmitter is enabled
 * is an Insert Into Loop action. Upon receipt of a GoAhead sequence (RxAbort)
 * we must clear CMR:13 to begin repeating TxData to RxData
 */
static void usc_loopmode_insert_request( struct mgsl_struct * info )
{
 	info->loopmode_insert_requested = true;
 
 	/* enable RxAbort irq. On next RxAbort, clear CMR:13 to
 	 * begin repeating TxData on RxData (complete insertion)
	 */
 	usc_OutReg( info, RICR, 
		(usc_InReg( info, RICR ) | RXSTATUS_ABORT_RECEIVED ) );
		
	/* set CMR:13 to insert into loop on next GoAhead (RxAbort) */
	info->cmr_value |= BIT13;
 	usc_OutReg(info, CMR, info->cmr_value);
}

/* return 1 if station is inserted into the loop, otherwise 0
 */
static int usc_loopmode_active( struct mgsl_struct * info)
{
 	return usc_InReg( info, CCSR ) & BIT7 ? 1 : 0 ;
}

#if SYNCLINK_GENERIC_HDLC

/**
 * called by generic HDLC layer when protocol selected (PPP, frame relay, etc.)
 * set encoding and frame check sequence (FCS) options
 *
 * dev       pointer to network device structure
 * encoding  serial encoding setting
 * parity    FCS setting
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_attach(struct net_device *dev, unsigned short encoding,
			  unsigned short parity)
{
	struct mgsl_struct *info = dev_to_port(dev);
	unsigned char  new_encoding;
	unsigned short new_crctype;

	/* return error if TTY interface open */
	if (info->port.count)
		return -EBUSY;

	switch (encoding)
	{
	case ENCODING_NRZ:        new_encoding = HDLC_ENCODING_NRZ; break;
	case ENCODING_NRZI:       new_encoding = HDLC_ENCODING_NRZI_SPACE; break;
	case ENCODING_FM_MARK:    new_encoding = HDLC_ENCODING_BIPHASE_MARK; break;
	case ENCODING_FM_SPACE:   new_encoding = HDLC_ENCODING_BIPHASE_SPACE; break;
	case ENCODING_MANCHESTER: new_encoding = HDLC_ENCODING_BIPHASE_LEVEL; break;
	default: return -EINVAL;
	}

	switch (parity)
	{
	case PARITY_NONE:            new_crctype = HDLC_CRC_NONE; break;
	case PARITY_CRC16_PR1_CCITT: new_crctype = HDLC_CRC_16_CCITT; break;
	case PARITY_CRC32_PR1_CCITT: new_crctype = HDLC_CRC_32_CCITT; break;
	default: return -EINVAL;
	}

	info->params.encoding = new_encoding;
	info->params.crc_type = new_crctype;

	/* if network interface up, reprogram hardware */
	if (info->netcount)
		mgsl_program_hw(info);

	return 0;
}

/**
 * called by generic HDLC layer to send frame
 *
 * skb  socket buffer containing HDLC frame
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct mgsl_struct *info = dev_to_port(dev);
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk(KERN_INFO "%s:hdlc_xmit(%s)\n",__FILE__,dev->name);

	/* stop sending until this frame completes */
	netif_stop_queue(dev);

	/* copy data to device buffers */
	info->xmit_cnt = skb->len;
	mgsl_load_tx_dma_buffer(info, skb->data, skb->len);

	/* update network statistics */
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	/* done with socket buffer, so free it */
	dev_kfree_skb(skb);

	/* save start time for transmit timeout detection */
	dev->trans_start = jiffies;

	/* start hardware transmitter if necessary */
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (!info->tx_active)
	 	usc_start_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	return 0;
}

/**
 * called by network layer when interface enabled
 * claim resources and initialize hardware
 *
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_open(struct net_device *dev)
{
	struct mgsl_struct *info = dev_to_port(dev);
	int rc;
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s:hdlcdev_open(%s)\n",__FILE__,dev->name);

	/* generic HDLC layer open processing */
	if ((rc = hdlc_open(dev)))
		return rc;

	/* arbitrate between network and tty opens */
	spin_lock_irqsave(&info->netlock, flags);
	if (info->port.count != 0 || info->netcount != 0) {
		printk(KERN_WARNING "%s: hdlc_open returning busy\n", dev->name);
		spin_unlock_irqrestore(&info->netlock, flags);
		return -EBUSY;
	}
	info->netcount=1;
	spin_unlock_irqrestore(&info->netlock, flags);

	/* claim resources and init adapter */
	if ((rc = startup(info)) != 0) {
		spin_lock_irqsave(&info->netlock, flags);
		info->netcount=0;
		spin_unlock_irqrestore(&info->netlock, flags);
		return rc;
	}

	/* assert DTR and RTS, apply hardware settings */
	info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
	mgsl_program_hw(info);

	/* enable network layer transmit */
	dev->trans_start = jiffies;
	netif_start_queue(dev);

	/* inform generic HDLC layer of current DCD status */
	spin_lock_irqsave(&info->irq_spinlock, flags);
	usc_get_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock, flags);
	if (info->serial_signals & SerialSignal_DCD)
		netif_carrier_on(dev);
	else
		netif_carrier_off(dev);
	return 0;
}

/**
 * called by network layer when interface is disabled
 * shutdown hardware and release resources
 *
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_close(struct net_device *dev)
{
	struct mgsl_struct *info = dev_to_port(dev);
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s:hdlcdev_close(%s)\n",__FILE__,dev->name);

	netif_stop_queue(dev);

	/* shutdown adapter and release resources */
	shutdown(info);

	hdlc_close(dev);

	spin_lock_irqsave(&info->netlock, flags);
	info->netcount=0;
	spin_unlock_irqrestore(&info->netlock, flags);

	return 0;
}

/**
 * called by network layer to process IOCTL call to network device
 *
 * dev  pointer to network device structure
 * ifr  pointer to network interface request structure
 * cmd  IOCTL command code
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	const size_t size = sizeof(sync_serial_settings);
	sync_serial_settings new_line;
	sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
	struct mgsl_struct *info = dev_to_port(dev);
	unsigned int flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s:hdlcdev_ioctl(%s)\n",__FILE__,dev->name);

	/* return error if TTY interface open */
	if (info->port.count)
		return -EBUSY;

	if (cmd != SIOCWANDEV)
		return hdlc_ioctl(dev, ifr, cmd);

	switch(ifr->ifr_settings.type) {
	case IF_GET_IFACE: /* return current sync_serial_settings */

		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
		if (ifr->ifr_settings.size < size) {
			ifr->ifr_settings.size = size; /* data size wanted */
			return -ENOBUFS;
		}

		flags = info->params.flags & (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
					      HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
					      HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
					      HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);

		switch (flags){
		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN): new_line.clock_type = CLOCK_EXT; break;
		case (HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_INT; break;
		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_TXINT; break;
		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN): new_line.clock_type = CLOCK_TXFROMRX; break;
		default: new_line.clock_type = CLOCK_DEFAULT;
		}

		new_line.clock_rate = info->params.clock_speed;
		new_line.loopback   = info->params.loopback ? 1:0;

		if (copy_to_user(line, &new_line, size))
			return -EFAULT;
		return 0;

	case IF_IFACE_SYNC_SERIAL: /* set sync_serial_settings */

		if(!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (copy_from_user(&new_line, line, size))
			return -EFAULT;

		switch (new_line.clock_type)
		{
		case CLOCK_EXT:      flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN; break;
		case CLOCK_TXFROMRX: flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN; break;
		case CLOCK_INT:      flags = HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG;    break;
		case CLOCK_TXINT:    flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG;    break;
		case CLOCK_DEFAULT:  flags = info->params.flags &
					     (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
					      HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
					      HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
					      HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN); break;
		default: return -EINVAL;
		}

		if (new_line.loopback != 0 && new_line.loopback != 1)
			return -EINVAL;

		info->params.flags &= ~(HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
					HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
					HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
					HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);
		info->params.flags |= flags;

		info->params.loopback = new_line.loopback;

		if (flags & (HDLC_FLAG_RXC_BRG | HDLC_FLAG_TXC_BRG))
			info->params.clock_speed = new_line.clock_rate;
		else
			info->params.clock_speed = 0;

		/* if network interface up, reprogram hardware */
		if (info->netcount)
			mgsl_program_hw(info);
		return 0;

	default:
		return hdlc_ioctl(dev, ifr, cmd);
	}
}

/**
 * called by network layer when transmit timeout is detected
 *
 * dev  pointer to network device structure
 */
static void hdlcdev_tx_timeout(struct net_device *dev)
{
	struct mgsl_struct *info = dev_to_port(dev);
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("hdlcdev_tx_timeout(%s)\n",dev->name);

	dev->stats.tx_errors++;
	dev->stats.tx_aborted_errors++;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_stop_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	netif_wake_queue(dev);
}

/**
 * called by device driver when transmit completes
 * reenable network layer transmit if stopped
 *
 * info  pointer to device instance information
 */
static void hdlcdev_tx_done(struct mgsl_struct *info)
{
	if (netif_queue_stopped(info->netdev))
		netif_wake_queue(info->netdev);
}

/**
 * called by device driver when frame received
 * pass frame to network layer
 *
 * info  pointer to device instance information
 * buf   pointer to buffer contianing frame data
 * size  count of data bytes in buf
 */
static void hdlcdev_rx(struct mgsl_struct *info, char *buf, int size)
{
	struct sk_buff *skb = dev_alloc_skb(size);
	struct net_device *dev = info->netdev;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("hdlcdev_rx(%s)\n", dev->name);

	if (skb == NULL) {
		printk(KERN_NOTICE "%s: can't alloc skb, dropping packet\n",
		       dev->name);
		dev->stats.rx_dropped++;
		return;
	}

	memcpy(skb_put(skb, size), buf, size);

	skb->protocol = hdlc_type_trans(skb, dev);

	dev->stats.rx_packets++;
	dev->stats.rx_bytes += size;

	netif_rx(skb);
}

static const struct net_device_ops hdlcdev_ops = {
	.ndo_open       = hdlcdev_open,
	.ndo_stop       = hdlcdev_close,
	.ndo_change_mtu = hdlc_change_mtu,
	.ndo_start_xmit = hdlc_start_xmit,
	.ndo_do_ioctl   = hdlcdev_ioctl,
	.ndo_tx_timeout = hdlcdev_tx_timeout,
};

/**
 * called by device driver when adding device instance
 * do generic HDLC initialization
 *
 * info  pointer to device instance information
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_init(struct mgsl_struct *info)
{
	int rc;
	struct net_device *dev;
	hdlc_device *hdlc;

	/* allocate and initialize network and HDLC layer objects */

	if (!(dev = alloc_hdlcdev(info))) {
		printk(KERN_ERR "%s:hdlc device allocation failure\n",__FILE__);
		return -ENOMEM;
	}

	/* for network layer reporting purposes only */
	dev->base_addr = info->io_base;
	dev->irq       = info->irq_level;
	dev->dma       = info->dma_level;

	/* network layer callbacks and settings */
	dev->netdev_ops     = &hdlcdev_ops;
	dev->watchdog_timeo = 10 * HZ;
	dev->tx_queue_len   = 50;

	/* generic HDLC layer callbacks and settings */
	hdlc         = dev_to_hdlc(dev);
	hdlc->attach = hdlcdev_attach;
	hdlc->xmit   = hdlcdev_xmit;

	/* register objects with HDLC layer */
	if ((rc = register_hdlc_device(dev))) {
		printk(KERN_WARNING "%s:unable to register hdlc device\n",__FILE__);
		free_netdev(dev);
		return rc;
	}

	info->netdev = dev;
	return 0;
}

/**
 * called by device driver when removing device instance
 * do generic HDLC cleanup
 *
 * info  pointer to device instance information
 */
static void hdlcdev_exit(struct mgsl_struct *info)
{
	unregister_hdlc_device(info->netdev);
	free_netdev(info->netdev);
	info->netdev = NULL;
}

#endif /* CONFIG_HDLC */


static int __devinit synclink_init_one (struct pci_dev *dev,
					const struct pci_device_id *ent)
{
	struct mgsl_struct *info;

	if (pci_enable_device(dev)) {
		printk("error enabling pci device %p\n", dev);
		return -EIO;
	}

	if (!(info = mgsl_allocate_device())) {
		printk("can't allocate device instance data.\n");
		return -EIO;
	}

        /* Copy user configuration info to device instance data */
		
	info->io_base = pci_resource_start(dev, 2);
	info->irq_level = dev->irq;
	info->phys_memory_base = pci_resource_start(dev, 3);
				
        /* Because veremap only works on page boundaries we must map
	 * a larger area than is actually implemented for the LCR
	 * memory range. We map a full page starting at the page boundary.
	 */
	info->phys_lcr_base = pci_resource_start(dev, 0);
	info->lcr_offset    = info->phys_lcr_base & (PAGE_SIZE-1);
	info->phys_lcr_base &= ~(PAGE_SIZE-1);
				
	info->bus_type = MGSL_BUS_TYPE_PCI;
	info->io_addr_size = 8;
	info->irq_flags = IRQF_SHARED;

	if (dev->device == 0x0210) {
		/* Version 1 PCI9030 based universal PCI adapter */
		info->misc_ctrl_value = 0x007c4080;
		info->hw_version = 1;
	} else {
		/* Version 0 PCI9050 based 5V PCI adapter
		 * A PCI9050 bug prevents reading LCR registers if 
		 * LCR base address bit 7 is set. Maintain shadow
		 * value so we can write to LCR misc control reg.
		 */
		info->misc_ctrl_value = 0x087e4546;
		info->hw_version = 0;
	}
				
	mgsl_add_device(info);

	return 0;
}

static void __devexit synclink_remove_one (struct pci_dev *dev)
{
}