aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/ieee1394/dv1394.c
blob: cbbbe14b88495f1382ca7b19acf732a0844fd34e (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
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
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345








































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                                                                                             

                                                                                   















                                                             
                                                             









































































































































































































































































































                                                                                                    
/*
 * dv1394.c - DV input/output over IEEE 1394 on OHCI chips
 *   Copyright (C)2001 Daniel Maas <dmaas@dcine.com>
 *     receive by Dan Dennedy <dan@dennedy.org>
 *
 * based on:
 *  video1394.c - video driver for OHCI 1394 boards
 *  Copyright (C)1999,2000 Sebastien Rougeaux <sebastien.rougeaux@anu.edu.au>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
  OVERVIEW

  I designed dv1394 as a "pipe" that you can use to shoot DV onto a
  FireWire bus. In transmission mode, dv1394 does the following:

   1. accepts contiguous frames of DV data from user-space, via write()
      or mmap() (see dv1394.h for the complete API)
   2. wraps IEC 61883 packets around the DV data, inserting
      empty synchronization packets as necessary
   3. assigns accurate SYT timestamps to the outgoing packets
   4. shoots them out using the OHCI card's IT DMA engine

   Thanks to Dan Dennedy, we now have a receive mode that does the following:

   1. accepts raw IEC 61883 packets from the OHCI card
   2. re-assembles the DV data payloads into contiguous frames,
      discarding empty packets
   3. sends the DV data to user-space via read() or mmap()
*/

/*
  TODO:

  - tunable frame-drop behavior: either loop last frame, or halt transmission

  - use a scatter/gather buffer for DMA programs (f->descriptor_pool)
    so that we don't rely on allocating 64KB of contiguous kernel memory
    via pci_alloc_consistent()

  DONE:
  - during reception, better handling of dropped frames and continuity errors
  - during reception, prevent DMA from bypassing the irq tasklets
  - reduce irq rate during reception (1/250 packets).
  - add many more internal buffers during reception with scatter/gather dma.
  - add dbc (continuity) checking on receive, increment status.dropped_frames
    if not continuous.
  - restart IT DMA after a bus reset
  - safely obtain and release ISO Tx channels in cooperation with OHCI driver
  - map received DIF blocks to their proper location in DV frame (ensure
    recovery if dropped packet)
  - handle bus resets gracefully (OHCI card seems to take care of this itself(!))
  - do not allow resizing the user_buf once allocated; eliminate nuke_buffer_mappings
  - eliminated #ifdef DV1394_DEBUG_LEVEL by inventing macros debug_printk and irq_printk
  - added wmb() and mb() to places where PCI read/write ordering needs to be enforced
  - set video->id correctly
  - store video_cards in an array indexed by OHCI card ID, rather than a list
  - implement DMA context allocation to cooperate with other users of the OHCI
  - fix all XXX showstoppers
  - disable IR/IT DMA interrupts on shutdown
  - flush pci writes to the card by issuing a read
  - devfs and character device dispatching (* needs testing with Linux 2.2.x)
  - switch over to the new kernel DMA API (pci_map_*()) (* needs testing on platforms with IOMMU!)
  - keep all video_cards in a list (for open() via chardev), set file->private_data = video
  - dv1394_poll should indicate POLLIN when receiving buffers are available
  - add proc fs interface to set cip_n, cip_d, syt_offset, and video signal
  - expose xmit and recv as separate devices (not exclusive)
  - expose NTSC and PAL as separate devices (can be overridden)

*/

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/smp_lock.h>
#include <linux/bitops.h>
#include <asm/byteorder.h>
#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/delay.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/ioctl32.h>
#include <linux/compat.h>
#include <linux/cdev.h>

#include "ieee1394.h"
#include "ieee1394_types.h"
#include "nodemgr.h"
#include "hosts.h"
#include "ieee1394_core.h"
#include "highlevel.h"
#include "dv1394.h"
#include "dv1394-private.h"

#include "ohci1394.h"

#ifndef virt_to_page
#define virt_to_page(x) MAP_NR(x)
#endif

#ifndef vmalloc_32
#define vmalloc_32(x) vmalloc(x)
#endif


/* DEBUG LEVELS:
   0 - no debugging messages
   1 - some debugging messages, but none during DMA frame transmission
   2 - lots of messages, including during DMA frame transmission
       (will cause undeflows if your machine is too slow!)
*/

#define DV1394_DEBUG_LEVEL 0

/* for debugging use ONLY: allow more than one open() of the device */
/* #define DV1394_ALLOW_MORE_THAN_ONE_OPEN 1 */

#if DV1394_DEBUG_LEVEL >= 2
#define irq_printk( args... ) printk( args )
#else
#define irq_printk( args... )
#endif

#if DV1394_DEBUG_LEVEL >= 1
#define debug_printk( args... ) printk( args)
#else
#define debug_printk( args... )
#endif

/* issue a dummy PCI read to force the preceding write
   to be posted to the PCI bus immediately */

static inline void flush_pci_write(struct ti_ohci *ohci)
{
	mb();
	reg_read(ohci, OHCI1394_IsochronousCycleTimer);
}

static void it_tasklet_func(unsigned long data);
static void ir_tasklet_func(unsigned long data);

#ifdef CONFIG_COMPAT
static long dv1394_compat_ioctl(struct file *file, unsigned int cmd,
			       unsigned long arg);
#endif

/* GLOBAL DATA */

/* list of all video_cards */
static LIST_HEAD(dv1394_cards);
static DEFINE_SPINLOCK(dv1394_cards_lock);

/* translate from a struct file* to the corresponding struct video_card* */

static inline struct video_card* file_to_video_card(struct file *file)
{
	return (struct video_card*) file->private_data;
}

/*** FRAME METHODS *********************************************************/

static void frame_reset(struct frame *f)
{
	f->state = FRAME_CLEAR;
	f->done = 0;
	f->n_packets = 0;
	f->frame_begin_timestamp = NULL;
	f->assigned_timestamp = 0;
	f->cip_syt1 = NULL;
	f->cip_syt2 = NULL;
	f->mid_frame_timestamp = NULL;
	f->frame_end_timestamp = NULL;
	f->frame_end_branch = NULL;
}

static struct frame* frame_new(unsigned int frame_num, struct video_card *video)
{
	struct frame *f = kmalloc(sizeof(*f), GFP_KERNEL);
	if (!f)
		return NULL;

	f->video = video;
	f->frame_num = frame_num;

	f->header_pool = pci_alloc_consistent(f->video->ohci->dev, PAGE_SIZE, &f->header_pool_dma);
	if (!f->header_pool) {
		printk(KERN_ERR "dv1394: failed to allocate CIP header pool\n");
		kfree(f);
		return NULL;
	}

	debug_printk("dv1394: frame_new: allocated CIP header pool at virt 0x%08lx (contig) dma 0x%08lx size %ld\n",
		     (unsigned long) f->header_pool, (unsigned long) f->header_pool_dma, PAGE_SIZE);

	f->descriptor_pool_size = MAX_PACKETS * sizeof(struct DMA_descriptor_block);
	/* make it an even # of pages */
	f->descriptor_pool_size += PAGE_SIZE - (f->descriptor_pool_size%PAGE_SIZE);

	f->descriptor_pool = pci_alloc_consistent(f->video->ohci->dev,
						  f->descriptor_pool_size,
						  &f->descriptor_pool_dma);
	if (!f->descriptor_pool) {
		pci_free_consistent(f->video->ohci->dev, PAGE_SIZE, f->header_pool, f->header_pool_dma);
		kfree(f);
		return NULL;
	}

	debug_printk("dv1394: frame_new: allocated DMA program memory at virt 0x%08lx (contig) dma 0x%08lx size %ld\n",
		     (unsigned long) f->descriptor_pool, (unsigned long) f->descriptor_pool_dma, f->descriptor_pool_size);

	f->data = 0;
	frame_reset(f);

	return f;
}

static void frame_delete(struct frame *f)
{
	pci_free_consistent(f->video->ohci->dev, PAGE_SIZE, f->header_pool, f->header_pool_dma);
	pci_free_consistent(f->video->ohci->dev, f->descriptor_pool_size, f->descriptor_pool, f->descriptor_pool_dma);
	kfree(f);
}




/*
   frame_prepare() - build the DMA program for transmitting

   Frame_prepare() must be called OUTSIDE the video->spinlock.
   However, frame_prepare() must still be serialized, so
   it should be called WITH the video->sem taken.
 */

static void frame_prepare(struct video_card *video, unsigned int this_frame)
{
	struct frame *f = video->frames[this_frame];
	int last_frame;

	struct DMA_descriptor_block *block;
	dma_addr_t block_dma;
	struct CIP_header *cip;
	dma_addr_t cip_dma;

	unsigned int n_descriptors, full_packets, packets_per_frame, payload_size;

	/* these flags denote packets that need special attention */
	int empty_packet, first_packet, last_packet, mid_packet;

	u32 *branch_address, *last_branch_address = NULL;
	unsigned long data_p;
	int first_packet_empty = 0;
	u32 cycleTimer, ct_sec, ct_cyc, ct_off;
	unsigned long irq_flags;

	irq_printk("frame_prepare( %d ) ---------------------\n", this_frame);

	full_packets = 0;



	if (video->pal_or_ntsc == DV1394_PAL)
		packets_per_frame = DV1394_PAL_PACKETS_PER_FRAME;
	else
		packets_per_frame = DV1394_NTSC_PACKETS_PER_FRAME;

	while ( full_packets < packets_per_frame ) {
		empty_packet = first_packet = last_packet = mid_packet = 0;

		data_p = f->data + full_packets * 480;

		/************************************************/
		/* allocate a descriptor block and a CIP header */
		/************************************************/

		/* note: these should NOT cross a page boundary (DMA restriction) */

		if (f->n_packets >= MAX_PACKETS) {
			printk(KERN_ERR "dv1394: FATAL ERROR: max packet count exceeded\n");
			return;
		}

		/* the block surely won't cross a page boundary,
		   since an even number of descriptor_blocks fit on a page */
		block = &(f->descriptor_pool[f->n_packets]);

		/* DMA address of the block = offset of block relative
		    to the kernel base address of the descriptor pool
		    + DMA base address of the descriptor pool */
		block_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;


		/* the whole CIP pool fits on one page, so no worries about boundaries */
		if ( ((unsigned long) &(f->header_pool[f->n_packets]) - (unsigned long) f->header_pool)
		    > PAGE_SIZE) {
			printk(KERN_ERR "dv1394: FATAL ERROR: no room to allocate CIP header\n");
			return;
		}

		cip = &(f->header_pool[f->n_packets]);

		/* DMA address of the CIP header = offset of cip
		   relative to kernel base address of the header pool
		   + DMA base address of the header pool */
		cip_dma = (unsigned long) cip % PAGE_SIZE + f->header_pool_dma;

		/* is this an empty packet? */

		if (video->cip_accum > (video->cip_d - video->cip_n)) {
			empty_packet = 1;
			payload_size = 8;
			video->cip_accum -= (video->cip_d - video->cip_n);
		} else {
			payload_size = 488;
			video->cip_accum += video->cip_n;
		}

		/* there are three important packets each frame:

		   the first packet in the frame - we ask the card to record the timestamp when
		                                   this packet is actually sent, so we can monitor
						   how accurate our timestamps are. Also, the first
						   packet serves as a semaphore to let us know that
						   it's OK to free the *previous* frame's DMA buffer

		   the last packet in the frame -  this packet is used to detect buffer underflows.
		                                   if this is the last ready frame, the last DMA block
						   will have a branch back to the beginning of the frame
						   (so that the card will re-send the frame on underflow).
						   if this branch gets taken, we know that at least one
						   frame has been dropped. When the next frame is ready,
						   the branch is pointed to its first packet, and the
						   semaphore is disabled.

		   a "mid" packet slightly before the end of the frame - this packet should trigger
		                   an interrupt so we can go and assign a timestamp to the first packet
				   in the next frame. We don't use the very last packet in the frame
				   for this purpose, because that would leave very little time to set
				   the timestamp before DMA starts on the next frame.
		*/

		if (f->n_packets == 0) {
			first_packet = 1;
		} else if ( full_packets == (packets_per_frame-1) ) {
			last_packet = 1;
		} else if (f->n_packets == packets_per_frame) {
			mid_packet = 1;
		}


		/********************/
		/* setup CIP header */
		/********************/

		/* the timestamp will be written later from the
		   mid-frame interrupt handler. For now we just
		   store the address of the CIP header(s) that
		   need a timestamp. */

		/* first packet in the frame needs a timestamp */
		if (first_packet) {
			f->cip_syt1 = cip;
			if (empty_packet)
				first_packet_empty = 1;

		} else if (first_packet_empty && (f->n_packets == 1) ) {
			/* if the first packet was empty, the second
			   packet's CIP header also needs a timestamp */
			f->cip_syt2 = cip;
		}

		fill_cip_header(cip,
				/* the node ID number of the OHCI card */
				reg_read(video->ohci, OHCI1394_NodeID) & 0x3F,
				video->continuity_counter,
				video->pal_or_ntsc,
				0xFFFF /* the timestamp is filled in later */);

		/* advance counter, only for full packets */
		if ( ! empty_packet )
			video->continuity_counter++;

		/******************************/
		/* setup DMA descriptor block */
		/******************************/

		/* first descriptor - OUTPUT_MORE_IMMEDIATE, for the controller's IT header */
		fill_output_more_immediate( &(block->u.out.omi), 1, video->channel, 0, payload_size);

		if (empty_packet) {
			/* second descriptor - OUTPUT_LAST for CIP header */
			fill_output_last( &(block->u.out.u.empty.ol),

					  /* want completion status on all interesting packets */
					  (first_packet || mid_packet || last_packet) ? 1 : 0,

					  /* want interrupts on all interesting packets */
					  (first_packet || mid_packet || last_packet) ? 1 : 0,

					  sizeof(struct CIP_header), /* data size */
					  cip_dma);

			if (first_packet)
				f->frame_begin_timestamp = &(block->u.out.u.empty.ol.q[3]);
			else if (mid_packet)
				f->mid_frame_timestamp = &(block->u.out.u.empty.ol.q[3]);
			else if (last_packet) {
				f->frame_end_timestamp = &(block->u.out.u.empty.ol.q[3]);
				f->frame_end_branch = &(block->u.out.u.empty.ol.q[2]);
			}

			branch_address = &(block->u.out.u.empty.ol.q[2]);
			n_descriptors = 3;
			if (first_packet)
				f->first_n_descriptors = n_descriptors;

		} else { /* full packet */

			/* second descriptor - OUTPUT_MORE for CIP header */
			fill_output_more( &(block->u.out.u.full.om),
					  sizeof(struct CIP_header), /* data size */
					  cip_dma);


			/* third (and possibly fourth) descriptor - for DV data */
			/* the 480-byte payload can cross a page boundary; if so,
			   we need to split it into two DMA descriptors */

			/* does the 480-byte data payload cross a page boundary? */
			if ( (PAGE_SIZE- ((unsigned long)data_p % PAGE_SIZE) ) < 480 ) {

				/* page boundary crossed */

				fill_output_more( &(block->u.out.u.full.u.cross.om),
						  /* data size - how much of data_p fits on the first page */
						  PAGE_SIZE - (data_p % PAGE_SIZE),

						  /* DMA address of data_p */
						  dma_region_offset_to_bus(&video->dv_buf,
									   data_p - (unsigned long) video->dv_buf.kvirt));

				fill_output_last( &(block->u.out.u.full.u.cross.ol),

						  /* want completion status on all interesting packets */
						  (first_packet || mid_packet || last_packet) ? 1 : 0,

						  /* want interrupt on all interesting packets */
						  (first_packet || mid_packet || last_packet) ? 1 : 0,

						  /* data size - remaining portion of data_p */
						  480 - (PAGE_SIZE - (data_p % PAGE_SIZE)),

						  /* DMA address of data_p + PAGE_SIZE - (data_p % PAGE_SIZE) */
						  dma_region_offset_to_bus(&video->dv_buf,
									   data_p + PAGE_SIZE - (data_p % PAGE_SIZE) - (unsigned long) video->dv_buf.kvirt));

				if (first_packet)
					f->frame_begin_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
				else if (mid_packet)
					f->mid_frame_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
				else if (last_packet) {
					f->frame_end_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
					f->frame_end_branch = &(block->u.out.u.full.u.cross.ol.q[2]);
				}

				branch_address = &(block->u.out.u.full.u.cross.ol.q[2]);

				n_descriptors = 5;
				if (first_packet)
					f->first_n_descriptors = n_descriptors;

				full_packets++;

			} else {
				/* fits on one page */

				fill_output_last( &(block->u.out.u.full.u.nocross.ol),

						  /* want completion status on all interesting packets */
						  (first_packet || mid_packet || last_packet) ? 1 : 0,

						  /* want interrupt on all interesting packets */
						  (first_packet || mid_packet || last_packet) ? 1 : 0,

						  480, /* data size (480 bytes of DV data) */


						  /* DMA address of data_p */
						  dma_region_offset_to_bus(&video->dv_buf,
									   data_p - (unsigned long) video->dv_buf.kvirt));

				if (first_packet)
					f->frame_begin_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
				else if (mid_packet)
					f->mid_frame_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
				else if (last_packet) {
					f->frame_end_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
					f->frame_end_branch = &(block->u.out.u.full.u.nocross.ol.q[2]);
				}

				branch_address = &(block->u.out.u.full.u.nocross.ol.q[2]);

				n_descriptors = 4;
				if (first_packet)
					f->first_n_descriptors = n_descriptors;

				full_packets++;
			}
		}

		/* link this descriptor block into the DMA program by filling in
		   the branch address of the previous block */

		/* note: we are not linked into the active DMA chain yet */

		if (last_branch_address) {
			*(last_branch_address) = cpu_to_le32(block_dma | n_descriptors);
		}

		last_branch_address = branch_address;


		f->n_packets++;

	}

	/* when we first assemble a new frame, set the final branch
	   to loop back up to the top */
	*(f->frame_end_branch) = cpu_to_le32(f->descriptor_pool_dma | f->first_n_descriptors);

	/* make the latest version of this frame visible to the PCI card */
	dma_region_sync_for_device(&video->dv_buf, f->data - (unsigned long) video->dv_buf.kvirt, video->frame_size);

	/* lock against DMA interrupt */
	spin_lock_irqsave(&video->spinlock, irq_flags);

	f->state = FRAME_READY;

	video->n_clear_frames--;

	last_frame = video->first_clear_frame - 1;
	if (last_frame == -1)
		last_frame = video->n_frames-1;

	video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;

	irq_printk("   frame %d prepared, active_frame = %d, n_clear_frames = %d, first_clear_frame = %d\n last=%d\n",
		   this_frame, video->active_frame, video->n_clear_frames, video->first_clear_frame, last_frame);

	irq_printk("   begin_ts %08lx mid_ts %08lx end_ts %08lx end_br %08lx\n",
		   (unsigned long) f->frame_begin_timestamp,
		   (unsigned long) f->mid_frame_timestamp,
		   (unsigned long) f->frame_end_timestamp,
		   (unsigned long) f->frame_end_branch);

	if (video->active_frame != -1) {

		/* if DMA is already active, we are almost done */
		/* just link us onto the active DMA chain */
		if (video->frames[last_frame]->frame_end_branch) {
			u32 temp;

			/* point the previous frame's tail to this frame's head */
			*(video->frames[last_frame]->frame_end_branch) = cpu_to_le32(f->descriptor_pool_dma | f->first_n_descriptors);

			/* this write MUST precede the next one, or we could silently drop frames */
			wmb();

			/* disable the want_status semaphore on the last packet */
			temp = le32_to_cpu(*(video->frames[last_frame]->frame_end_branch - 2));
			temp &= 0xF7CFFFFF;
			*(video->frames[last_frame]->frame_end_branch - 2) = cpu_to_le32(temp);

			/* flush these writes to memory ASAP */
			flush_pci_write(video->ohci);

			/* NOTE:
			   ideally the writes should be "atomic": if
			   the OHCI card reads the want_status flag in
			   between them, we'll falsely report a
			   dropped frame. Hopefully this window is too
			   small to really matter, and the consequence
			   is rather harmless. */


			irq_printk("     new frame %d linked onto DMA chain\n", this_frame);

		} else {
			printk(KERN_ERR "dv1394: last frame not ready???\n");
		}

	} else {

		u32 transmit_sec, transmit_cyc;
		u32 ts_cyc, ts_off;

		/* DMA is stopped, so this is the very first frame */
		video->active_frame = this_frame;

	        /* set CommandPtr to address and size of first descriptor block */
		reg_write(video->ohci, video->ohci_IsoXmitCommandPtr,
			  video->frames[video->active_frame]->descriptor_pool_dma |
			  f->first_n_descriptors);

		/* assign a timestamp based on the current cycle time...
		   We'll tell the card to begin DMA 100 cycles from now,
		   and assign a timestamp 103 cycles from now */

		cycleTimer = reg_read(video->ohci, OHCI1394_IsochronousCycleTimer);

		ct_sec = cycleTimer >> 25;
		ct_cyc = (cycleTimer >> 12) & 0x1FFF;
		ct_off = cycleTimer & 0xFFF;

		transmit_sec = ct_sec;
		transmit_cyc = ct_cyc + 100;

		transmit_sec += transmit_cyc/8000;
		transmit_cyc %= 8000;

		ts_off = ct_off;
		ts_cyc = transmit_cyc + 3;
		ts_cyc %= 8000;

		f->assigned_timestamp = (ts_cyc&0xF) << 12;

		/* now actually write the timestamp into the appropriate CIP headers */
		if (f->cip_syt1) {
			f->cip_syt1->b[6] = f->assigned_timestamp >> 8;
			f->cip_syt1->b[7] = f->assigned_timestamp & 0xFF;
		}
		if (f->cip_syt2) {
			f->cip_syt2->b[6] = f->assigned_timestamp >> 8;
			f->cip_syt2->b[7] = f->assigned_timestamp & 0xFF;
		}

		/* --- start DMA --- */

		/* clear all bits in ContextControl register */

		reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, 0xFFFFFFFF);
		wmb();

		/* the OHCI card has the ability to start ISO transmission on a
		   particular cycle (start-on-cycle). This way we can ensure that
		   the first DV frame will have an accurate timestamp.

		   However, start-on-cycle only appears to work if the OHCI card
		   is cycle master! Since the consequences of messing up the first
		   timestamp are minimal*, just disable start-on-cycle for now.

		   * my DV deck drops the first few frames before it "locks in;"
		     so the first frame having an incorrect timestamp is inconsequential.
		*/

#if 0
		reg_write(video->ohci, video->ohci_IsoXmitContextControlSet,
			  (1 << 31) /* enable start-on-cycle */
			  | ( (transmit_sec & 0x3) << 29)
			  | (transmit_cyc << 16));
		wmb();
#endif

		video->dma_running = 1;

		/* set the 'run' bit */
		reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, 0x8000);
		flush_pci_write(video->ohci);

		/* --- DMA should be running now --- */

		debug_printk("    Cycle = %4u ContextControl = %08x CmdPtr = %08x\n",
			     (reg_read(video->ohci, OHCI1394_IsochronousCycleTimer) >> 12) & 0x1FFF,
			     reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
			     reg_read(video->ohci, video->ohci_IsoXmitCommandPtr));

		debug_printk("    DMA start - current cycle %4u, transmit cycle %4u (%2u), assigning ts cycle %2u\n",
			     ct_cyc, transmit_cyc, transmit_cyc & 0xF, ts_cyc & 0xF);

#if DV1394_DEBUG_LEVEL >= 2
		{
			/* check if DMA is really running */
			int i = 0;
			while (i < 20) {
				mb();
				mdelay(1);
				if (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & (1 << 10)) {
					printk("DMA ACTIVE after %d msec\n", i);
					break;
				}
				i++;
			}

			printk("set = %08x, cmdPtr = %08x\n",
			       reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
			       reg_read(video->ohci, video->ohci_IsoXmitCommandPtr)
			       );

			if ( ! (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) &  (1 << 10)) ) {
				printk("DMA did NOT go active after 20ms, event = %x\n",
				       reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & 0x1F);
			} else
				printk("DMA is RUNNING!\n");
		}
#endif

	}


	spin_unlock_irqrestore(&video->spinlock, irq_flags);
}



/*** RECEIVE FUNCTIONS *****************************************************/

/*
	frame method put_packet

	map and copy the packet data to its location in the frame
	based upon DIF section and sequence
*/

static void inline
frame_put_packet (struct frame *f, struct packet *p)
{
	int section_type = p->data[0] >> 5;           /* section type is in bits 5 - 7 */
	int dif_sequence = p->data[1] >> 4;           /* dif sequence number is in bits 4 - 7 */
	int dif_block = p->data[2];

	/* sanity check */
	if (dif_sequence > 11 || dif_block > 149) return;

	switch (section_type) {
	case 0:           /* 1 Header block */
	        memcpy( (void *) f->data + dif_sequence * 150 * 80, p->data, 480);
	        break;

	case 1:           /* 2 Subcode blocks */
	        memcpy( (void *) f->data + dif_sequence * 150 * 80 + (1 + dif_block) * 80, p->data, 480);
	        break;

	case 2:           /* 3 VAUX blocks */
	        memcpy( (void *) f->data + dif_sequence * 150 * 80 + (3 + dif_block) * 80, p->data, 480);
	        break;

	case 3:           /* 9 Audio blocks interleaved with video */
	        memcpy( (void *) f->data + dif_sequence * 150 * 80 + (6 + dif_block * 16) * 80, p->data, 480);
	        break;

	case 4:           /* 135 Video blocks interleaved with audio */
	        memcpy( (void *) f->data + dif_sequence * 150 * 80 + (7 + (dif_block / 15) + dif_block) * 80, p->data, 480);
	        break;

	default:           /* we can not handle any other data */
	        break;
	}
}


static void start_dma_receive(struct video_card *video)
{
	if (video->first_run == 1) {
		video->first_run = 0;

		/* start DMA once all of the frames are READY */
		video->n_clear_frames = 0;
		video->first_clear_frame = -1;
		video->current_packet = 0;
		video->active_frame = 0;

		/* reset iso recv control register */
		reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, 0xFFFFFFFF);
		wmb();

		/* clear bufferFill, set isochHeader and speed (0=100) */
		reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, 0x40000000);

		/* match on all tags, listen on channel */
		reg_write(video->ohci, video->ohci_IsoRcvContextMatch, 0xf0000000 | video->channel);

		/* address and first descriptor block + Z=1 */
		reg_write(video->ohci, video->ohci_IsoRcvCommandPtr,
			  video->frames[0]->descriptor_pool_dma | 1); /* Z=1 */
		wmb();

		video->dma_running = 1;

		/* run */
		reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, 0x8000);
		flush_pci_write(video->ohci);

		debug_printk("dv1394: DMA started\n");

#if DV1394_DEBUG_LEVEL >= 2
		{
			int i;

			for (i = 0; i < 1000; ++i) {
				mdelay(1);
				if (reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & (1 << 10)) {
					printk("DMA ACTIVE after %d msec\n", i);
					break;
				}
			}
			if ( reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) &  (1 << 11) ) {
				printk("DEAD, event = %x\n",
					   reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & 0x1F);
			} else
				printk("RUNNING!\n");
		}
#endif
	} else if ( reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) &  (1 << 11) ) {
		debug_printk("DEAD, event = %x\n",
			     reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & 0x1F);

		/* wake */
		reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));
	}
}


/*
   receive_packets() - build the DMA program for receiving
*/

static void receive_packets(struct video_card *video)
{
	struct DMA_descriptor_block *block = NULL;
	dma_addr_t block_dma = 0;
	struct packet *data = NULL;
	dma_addr_t data_dma = 0;
	u32 *last_branch_address = NULL;
	unsigned long irq_flags;
	int want_interrupt = 0;
	struct frame *f = NULL;
	int i, j;

	spin_lock_irqsave(&video->spinlock, irq_flags);

	for (j = 0; j < video->n_frames; j++) {

		/* connect frames */
		if (j > 0 && f != NULL && f->frame_end_branch != NULL)
			*(f->frame_end_branch) = cpu_to_le32(video->frames[j]->descriptor_pool_dma | 1); /* set Z=1 */

		f = video->frames[j];

		for (i = 0; i < MAX_PACKETS; i++) {
			/* locate a descriptor block and packet from the buffer */
			block = &(f->descriptor_pool[i]);
			block_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;

			data = ((struct packet*)video->packet_buf.kvirt) + f->frame_num * MAX_PACKETS + i;
			data_dma = dma_region_offset_to_bus( &video->packet_buf,
							     ((unsigned long) data - (unsigned long) video->packet_buf.kvirt) );

			/* setup DMA descriptor block */
			want_interrupt = ((i % (MAX_PACKETS/2)) == 0 || i == (MAX_PACKETS-1));
			fill_input_last( &(block->u.in.il), want_interrupt, 512, data_dma);

			/* link descriptors */
			last_branch_address = f->frame_end_branch;

			if (last_branch_address != NULL)
				*(last_branch_address) = cpu_to_le32(block_dma | 1); /* set Z=1 */

			f->frame_end_branch = &(block->u.in.il.q[2]);
		}

	} /* next j */

	spin_unlock_irqrestore(&video->spinlock, irq_flags);

}



/*** MANAGEMENT FUNCTIONS **************************************************/

static int do_dv1394_init(struct video_card *video, struct dv1394_init *init)
{
	unsigned long flags, new_buf_size;
	int i;
	u64 chan_mask;
	int retval = -EINVAL;

	debug_printk("dv1394: initialising %d\n", video->id);
	if (init->api_version != DV1394_API_VERSION)
		return -EINVAL;

	/* first sanitize all the parameters */
	if ( (init->n_frames < 2) || (init->n_frames > DV1394_MAX_FRAMES) )
		return -EINVAL;

	if ( (init->format != DV1394_NTSC) && (init->format != DV1394_PAL) )
		return -EINVAL;

	if ( (init->syt_offset == 0) || (init->syt_offset > 50) )
		/* default SYT offset is 3 cycles */
		init->syt_offset = 3;

	if ( (init->channel > 63) || (init->channel < 0) )
		init->channel = 63;

	chan_mask = (u64)1 << init->channel;

	/* calculate what size DMA buffer is needed */
	if (init->format == DV1394_NTSC)
		new_buf_size = DV1394_NTSC_FRAME_SIZE * init->n_frames;
	else
		new_buf_size = DV1394_PAL_FRAME_SIZE * init->n_frames;

	/* round up to PAGE_SIZE */
	if (new_buf_size % PAGE_SIZE) new_buf_size += PAGE_SIZE - (new_buf_size % PAGE_SIZE);

	/* don't allow the user to allocate the DMA buffer more than once */
	if (video->dv_buf.kvirt && video->dv_buf_size != new_buf_size) {
		printk("dv1394: re-sizing the DMA buffer is not allowed\n");
		return -EINVAL;
	}

	/* shutdown the card if it's currently active */
	/* (the card should not be reset if the parameters are screwy) */

	do_dv1394_shutdown(video, 0);

	/* try to claim the ISO channel */
	spin_lock_irqsave(&video->ohci->IR_channel_lock, flags);
	if (video->ohci->ISO_channel_usage & chan_mask) {
		spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);
		retval = -EBUSY;
		goto err;
	}
	video->ohci->ISO_channel_usage |= chan_mask;
	spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);

	video->channel = init->channel;

	/* initialize misc. fields of video */
	video->n_frames = init->n_frames;
	video->pal_or_ntsc = init->format;

	video->cip_accum = 0;
	video->continuity_counter = 0;

	video->active_frame = -1;
	video->first_clear_frame = 0;
	video->n_clear_frames = video->n_frames;
	video->dropped_frames = 0;

	video->write_off = 0;

	video->first_run = 1;
	video->current_packet = -1;
	video->first_frame = 0;

	if (video->pal_or_ntsc == DV1394_NTSC) {
		video->cip_n = init->cip_n != 0 ? init->cip_n : CIP_N_NTSC;
		video->cip_d = init->cip_d != 0 ? init->cip_d : CIP_D_NTSC;
		video->frame_size = DV1394_NTSC_FRAME_SIZE;
	} else {
		video->cip_n = init->cip_n != 0 ? init->cip_n : CIP_N_PAL;
		video->cip_d = init->cip_d != 0 ? init->cip_d : CIP_D_PAL;
		video->frame_size = DV1394_PAL_FRAME_SIZE;
	}

	video->syt_offset = init->syt_offset;

	/* find and claim DMA contexts on the OHCI card */

	if (video->ohci_it_ctx == -1) {
		ohci1394_init_iso_tasklet(&video->it_tasklet, OHCI_ISO_TRANSMIT,
					  it_tasklet_func, (unsigned long) video);

		if (ohci1394_register_iso_tasklet(video->ohci, &video->it_tasklet) < 0) {
			printk(KERN_ERR "dv1394: could not find an available IT DMA context\n");
			retval = -EBUSY;
			goto err;
		}

		video->ohci_it_ctx = video->it_tasklet.context;
		debug_printk("dv1394: claimed IT DMA context %d\n", video->ohci_it_ctx);
	}

	if (video->ohci_ir_ctx == -1) {
		ohci1394_init_iso_tasklet(&video->ir_tasklet, OHCI_ISO_RECEIVE,
					  ir_tasklet_func, (unsigned long) video);

		if (ohci1394_register_iso_tasklet(video->ohci, &video->ir_tasklet) < 0) {
			printk(KERN_ERR "dv1394: could not find an available IR DMA context\n");
			retval = -EBUSY;
			goto err;
		}
		video->ohci_ir_ctx = video->ir_tasklet.context;
		debug_printk("dv1394: claimed IR DMA context %d\n", video->ohci_ir_ctx);
	}

	/* allocate struct frames */
	for (i = 0; i < init->n_frames; i++) {
		video->frames[i] = frame_new(i, video);

		if (!video->frames[i]) {
			printk(KERN_ERR "dv1394: Cannot allocate frame structs\n");
			retval = -ENOMEM;
			goto err;
		}
	}

	if (!video->dv_buf.kvirt) {
		/* allocate the ringbuffer */
		retval = dma_region_alloc(&video->dv_buf, new_buf_size, video->ohci->dev, PCI_DMA_TODEVICE);
		if (retval)
			goto err;

		video->dv_buf_size = new_buf_size;

		debug_printk("dv1394: Allocated %d frame buffers, total %u pages (%u DMA pages), %lu bytes\n", 
			     video->n_frames, video->dv_buf.n_pages,
			     video->dv_buf.n_dma_pages, video->dv_buf_size);
	}

	/* set up the frame->data pointers */
	for (i = 0; i < video->n_frames; i++)
		video->frames[i]->data = (unsigned long) video->dv_buf.kvirt + i * video->frame_size;

	if (!video->packet_buf.kvirt) {
		/* allocate packet buffer */
		video->packet_buf_size = sizeof(struct packet) * video->n_frames * MAX_PACKETS;
		if (video->packet_buf_size % PAGE_SIZE)
			video->packet_buf_size += PAGE_SIZE - (video->packet_buf_size % PAGE_SIZE);

		retval = dma_region_alloc(&video->packet_buf, video->packet_buf_size,
					  video->ohci->dev, PCI_DMA_FROMDEVICE);
		if (retval)
			goto err;

		debug_printk("dv1394: Allocated %d packets in buffer, total %u pages (%u DMA pages), %lu bytes\n",
				 video->n_frames*MAX_PACKETS, video->packet_buf.n_pages,
				 video->packet_buf.n_dma_pages, video->packet_buf_size);
	}

	/* set up register offsets for IT context */
	/* IT DMA context registers are spaced 16 bytes apart */
	video->ohci_IsoXmitContextControlSet = OHCI1394_IsoXmitContextControlSet+16*video->ohci_it_ctx;
	video->ohci_IsoXmitContextControlClear = OHCI1394_IsoXmitContextControlClear+16*video->ohci_it_ctx;
	video->ohci_IsoXmitCommandPtr = OHCI1394_IsoXmitCommandPtr+16*video->ohci_it_ctx;

	/* enable interrupts for IT context */
	reg_write(video->ohci, OHCI1394_IsoXmitIntMaskSet, (1 << video->ohci_it_ctx));
	debug_printk("dv1394: interrupts enabled for IT context %d\n", video->ohci_it_ctx);

	/* set up register offsets for IR context */
	/* IR DMA context registers are spaced 32 bytes apart */
	video->ohci_IsoRcvContextControlSet = OHCI1394_IsoRcvContextControlSet+32*video->ohci_ir_ctx;
	video->ohci_IsoRcvContextControlClear = OHCI1394_IsoRcvContextControlClear+32*video->ohci_ir_ctx;
	video->ohci_IsoRcvCommandPtr = OHCI1394_IsoRcvCommandPtr+32*video->ohci_ir_ctx;
	video->ohci_IsoRcvContextMatch = OHCI1394_IsoRcvContextMatch+32*video->ohci_ir_ctx;

	/* enable interrupts for IR context */
	reg_write(video->ohci, OHCI1394_IsoRecvIntMaskSet, (1 << video->ohci_ir_ctx) );
	debug_printk("dv1394: interrupts enabled for IR context %d\n", video->ohci_ir_ctx);

	return 0;

err:
	do_dv1394_shutdown(video, 1);
	return retval;
}

/* if the user doesn't bother to call ioctl(INIT) before starting
   mmap() or read()/write(), just give him some default values */

static int do_dv1394_init_default(struct video_card *video)
{
	struct dv1394_init init;

	init.api_version = DV1394_API_VERSION;
	init.n_frames = DV1394_MAX_FRAMES / 4;
	/* the following are now set via devfs */
	init.channel = video->channel;
	init.format = video->pal_or_ntsc;
	init.cip_n = video->cip_n;
	init.cip_d = video->cip_d;
	init.syt_offset = video->syt_offset;

	return do_dv1394_init(video, &init);
}

/* do NOT call from interrupt context */
static void stop_dma(struct video_card *video)
{
	unsigned long flags;
	int i;

	/* no interrupts */
	spin_lock_irqsave(&video->spinlock, flags);

	video->dma_running = 0;

	if ( (video->ohci_it_ctx == -1) && (video->ohci_ir_ctx == -1) )
		goto out;

	/* stop DMA if in progress */
	if ( (video->active_frame != -1) ||
	    (reg_read(video->ohci, video->ohci_IsoXmitContextControlClear) & (1 << 10)) ||
	    (reg_read(video->ohci, video->ohci_IsoRcvContextControlClear) &  (1 << 10)) ) {

		/* clear the .run bits */
		reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, (1 << 15));
		reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, (1 << 15));
		flush_pci_write(video->ohci);

		video->active_frame = -1;
		video->first_run = 1;

		/* wait until DMA really stops */
		i = 0;
		while (i < 1000) {

			/* wait 0.1 millisecond */
			udelay(100);

			if ( (reg_read(video->ohci, video->ohci_IsoXmitContextControlClear) & (1 << 10)) ||
			    (reg_read(video->ohci, video->ohci_IsoRcvContextControlClear)  & (1 << 10)) ) {
				/* still active */
				debug_printk("dv1394: stop_dma: DMA not stopped yet\n" );
				mb();
			} else {
				debug_printk("dv1394: stop_dma: DMA stopped safely after %d ms\n", i/10);
				break;
			}

			i++;
		}

		if (i == 1000) {
			printk(KERN_ERR "dv1394: stop_dma: DMA still going after %d ms!\n", i/10);
		}
	}
	else
		debug_printk("dv1394: stop_dma: already stopped.\n");

out:
	spin_unlock_irqrestore(&video->spinlock, flags);
}



static void do_dv1394_shutdown(struct video_card *video, int free_dv_buf)
{
	int i;

	debug_printk("dv1394: shutdown...\n");

	/* stop DMA if in progress */
	stop_dma(video);

	/* release the DMA contexts */
	if (video->ohci_it_ctx != -1) {
		video->ohci_IsoXmitContextControlSet = 0;
		video->ohci_IsoXmitContextControlClear = 0;
		video->ohci_IsoXmitCommandPtr = 0;

		/* disable interrupts for IT context */
		reg_write(video->ohci, OHCI1394_IsoXmitIntMaskClear, (1 << video->ohci_it_ctx));

		/* remove tasklet */
		ohci1394_unregister_iso_tasklet(video->ohci, &video->it_tasklet);
		debug_printk("dv1394: IT context %d released\n", video->ohci_it_ctx);
		video->ohci_it_ctx = -1;
	}

	if (video->ohci_ir_ctx != -1) {
		video->ohci_IsoRcvContextControlSet = 0;
		video->ohci_IsoRcvContextControlClear = 0;
		video->ohci_IsoRcvCommandPtr = 0;
		video->ohci_IsoRcvContextMatch = 0;

		/* disable interrupts for IR context */
		reg_write(video->ohci, OHCI1394_IsoRecvIntMaskClear, (1 << video->ohci_ir_ctx));

		/* remove tasklet */
		ohci1394_unregister_iso_tasklet(video->ohci, &video->ir_tasklet);
		debug_printk("dv1394: IR context %d released\n", video->ohci_ir_ctx);
		video->ohci_ir_ctx = -1;
	}

	/* release the ISO channel */
	if (video->channel != -1) {
		u64 chan_mask;
		unsigned long flags;

		chan_mask = (u64)1 << video->channel;

		spin_lock_irqsave(&video->ohci->IR_channel_lock, flags);
		video->ohci->ISO_channel_usage &= ~(chan_mask);
		spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);

		video->channel = -1;
	}

	/* free the frame structs */
	for (i = 0; i < DV1394_MAX_FRAMES; i++) {
		if (video->frames[i])
			frame_delete(video->frames[i]);
		video->frames[i] = NULL;
	}

	video->n_frames = 0;

	/* we can't free the DMA buffer unless it is guaranteed that
	   no more user-space mappings exist */

	if (free_dv_buf) {
		dma_region_free(&video->dv_buf);
		video->dv_buf_size = 0;
	}

	/* free packet buffer */
	dma_region_free(&video->packet_buf);
	video->packet_buf_size = 0;

	debug_printk("dv1394: shutdown OK\n");
}

/*
       **********************************
       *** MMAP() THEORY OF OPERATION ***
       **********************************

        The ringbuffer cannot be re-allocated or freed while
        a user program maintains a mapping of it. (note that a mapping
	can persist even after the device fd is closed!)

	So, only let the user process allocate the DMA buffer once.
	To resize or deallocate it, you must close the device file
	and open it again.

	Previously Dan M. hacked out a scheme that allowed the DMA
	buffer to change by forcefully unmapping it from the user's
	address space. It was prone to error because it's very hard to
	track all the places the buffer could have been mapped (we
	would have had to walk the vma list of every process in the
	system to be sure we found all the mappings!). Instead, we
	force the user to choose one buffer size and stick with
	it. This small sacrifice is worth the huge reduction in
	error-prone code in dv1394.
*/

static int dv1394_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct video_card *video = file_to_video_card(file);
	int retval = -EINVAL;

	/* serialize mmap */
	down(&video->sem);

	if ( ! video_card_initialized(video) ) {
		retval = do_dv1394_init_default(video);
		if (retval)
			goto out;
	}

	retval = dma_region_mmap(&video->dv_buf, file, vma);
out:
	up(&video->sem);
	return retval;
}

/*** DEVICE FILE INTERFACE *************************************************/

/* no need to serialize, multiple threads OK */
static unsigned int dv1394_poll(struct file *file, struct poll_table_struct *wait)
{
	struct video_card *video = file_to_video_card(file);
	unsigned int mask = 0;
	unsigned long flags;

	poll_wait(file, &video->waitq, wait);

	spin_lock_irqsave(&video->spinlock, flags);
	if ( video->n_frames == 0 ) {

	} else if ( video->active_frame == -1 ) {
		/* nothing going on */
		mask |= POLLOUT;
	} else {
		/* any clear/ready buffers? */
		if (video->n_clear_frames >0)
			mask |= POLLOUT | POLLIN;
	}
	spin_unlock_irqrestore(&video->spinlock, flags);

	return mask;
}

static int dv1394_fasync(int fd, struct file *file, int on)
{
	/* I just copied this code verbatim from Alan Cox's mouse driver example
	   (Documentation/DocBook/) */

	struct video_card *video = file_to_video_card(file);

	int retval = fasync_helper(fd, file, on, &video->fasync);

	if (retval < 0)
		return retval;
        return 0;
}

static ssize_t dv1394_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct video_card *video = file_to_video_card(file);
	DECLARE_WAITQUEUE(wait, current);
	ssize_t ret;
	size_t cnt;
	unsigned long flags;
	int target_frame;

	/* serialize this to prevent multi-threaded mayhem */
	if (file->f_flags & O_NONBLOCK) {
		if (down_trylock(&video->sem))
			return -EAGAIN;
	} else {
		if (down_interruptible(&video->sem))
			return -ERESTARTSYS;
	}

	if ( !video_card_initialized(video) ) {
		ret = do_dv1394_init_default(video);
		if (ret) {
			up(&video->sem);
			return ret;
		}
	}

	ret = 0;
	add_wait_queue(&video->waitq, &wait);

	while (count > 0) {

		/* must set TASK_INTERRUPTIBLE *before* checking for free
		   buffers; otherwise we could miss a wakeup if the interrupt
		   fires between the check and the schedule() */

		set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irqsave(&video->spinlock, flags);

		target_frame = video->first_clear_frame;

		spin_unlock_irqrestore(&video->spinlock, flags);

		if (video->frames[target_frame]->state == FRAME_CLEAR) {

			/* how much room is left in the target frame buffer */
			cnt = video->frame_size - (video->write_off - target_frame * video->frame_size);

		} else {
			/* buffer is already used */
			cnt = 0;
		}

		if (cnt > count)
			cnt = count;

		if (cnt <= 0) {
			/* no room left, gotta wait */
			if (file->f_flags & O_NONBLOCK) {
				if (!ret)
					ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				if (!ret)
					ret = -ERESTARTSYS;
				break;
			}

			schedule();

			continue; /* start over from 'while(count > 0)...' */
		}

		if (copy_from_user(video->dv_buf.kvirt + video->write_off, buffer, cnt)) {
			if (!ret)
				ret = -EFAULT;
			break;
		}

		video->write_off = (video->write_off + cnt) % (video->n_frames * video->frame_size);

		count -= cnt;
		buffer += cnt;
		ret += cnt;

		if (video->write_off == video->frame_size * ((target_frame + 1) % video->n_frames))
				frame_prepare(video, target_frame);
	}

	remove_wait_queue(&video->waitq, &wait);
	set_current_state(TASK_RUNNING);
	up(&video->sem);
	return ret;
}


static ssize_t dv1394_read(struct file *file,  char __user *buffer, size_t count, loff_t *ppos)
{
	struct video_card *video = file_to_video_card(file);
	DECLARE_WAITQUEUE(wait, current);
	ssize_t ret;
	size_t cnt;
	unsigned long flags;
	int target_frame;

	/* serialize this to prevent multi-threaded mayhem */
	if (file->f_flags & O_NONBLOCK) {
		if (down_trylock(&video->sem))
			return -EAGAIN;
	} else {
		if (down_interruptible(&video->sem))
			return -ERESTARTSYS;
	}

	if ( !video_card_initialized(video) ) {
		ret = do_dv1394_init_default(video);
		if (ret) {
			up(&video->sem);
			return ret;
		}
		video->continuity_counter = -1;

		receive_packets(video);

		start_dma_receive(video);
	}

	ret = 0;
	add_wait_queue(&video->waitq, &wait);

	while (count > 0) {

		/* must set TASK_INTERRUPTIBLE *before* checking for free
		   buffers; otherwise we could miss a wakeup if the interrupt
		   fires between the check and the schedule() */

		set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irqsave(&video->spinlock, flags);

		target_frame = video->first_clear_frame;

		spin_unlock_irqrestore(&video->spinlock, flags);

		if (target_frame >= 0 &&
			video->n_clear_frames > 0 &&
			video->frames[target_frame]->state == FRAME_CLEAR) {

			/* how much room is left in the target frame buffer */
			cnt = video->frame_size - (video->write_off - target_frame * video->frame_size);

		} else {
			/* buffer is already used */
			cnt = 0;
		}

		if (cnt > count)
			cnt = count;

		if (cnt <= 0) {
			/* no room left, gotta wait */
			if (file->f_flags & O_NONBLOCK) {
				if (!ret)
					ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				if (!ret)
					ret = -ERESTARTSYS;
				break;
			}

			schedule();

			continue; /* start over from 'while(count > 0)...' */
		}

		if (copy_to_user(buffer, video->dv_buf.kvirt + video->write_off, cnt)) {
				if (!ret)
					ret = -EFAULT;
				break;
		}

		video->write_off = (video->write_off + cnt) % (video->n_frames * video->frame_size);

		count -= cnt;
		buffer += cnt;
		ret += cnt;

		if (video->write_off == video->frame_size * ((target_frame + 1) % video->n_frames)) {
			spin_lock_irqsave(&video->spinlock, flags);
			video->n_clear_frames--;
			video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;
			spin_unlock_irqrestore(&video->spinlock, flags);
		}
	}

	remove_wait_queue(&video->waitq, &wait);
	set_current_state(TASK_RUNNING);
	up(&video->sem);
	return ret;
}


/*** DEVICE IOCTL INTERFACE ************************************************/

static long dv1394_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct video_card *video;
	unsigned long flags;
	int ret = -EINVAL;
	void __user *argp = (void __user *)arg;

	DECLARE_WAITQUEUE(wait, current);

	lock_kernel();
	video = file_to_video_card(file);

	/* serialize this to prevent multi-threaded mayhem */
	if (file->f_flags & O_NONBLOCK) {
		if (down_trylock(&video->sem)) {
			unlock_kernel();
			return -EAGAIN;
		}
	} else {
		if (down_interruptible(&video->sem)) {
			unlock_kernel();
			return -ERESTARTSYS;
		}
	}

	switch(cmd)
	{
	case DV1394_IOC_SUBMIT_FRAMES: {
		unsigned int n_submit;

		if ( !video_card_initialized(video) ) {
			ret = do_dv1394_init_default(video);
			if (ret)
				goto out;
		}

		n_submit = (unsigned int) arg;

		if (n_submit > video->n_frames) {
			ret = -EINVAL;
			goto out;
		}

		while (n_submit > 0) {

			add_wait_queue(&video->waitq, &wait);
			set_current_state(TASK_INTERRUPTIBLE);

			spin_lock_irqsave(&video->spinlock, flags);

			/* wait until video->first_clear_frame is really CLEAR */
			while (video->frames[video->first_clear_frame]->state != FRAME_CLEAR) {

				spin_unlock_irqrestore(&video->spinlock, flags);

				if (signal_pending(current)) {
					remove_wait_queue(&video->waitq, &wait);
					set_current_state(TASK_RUNNING);
					ret = -EINTR;
					goto out;
				}

				schedule();
				set_current_state(TASK_INTERRUPTIBLE);

				spin_lock_irqsave(&video->spinlock, flags);
			}
			spin_unlock_irqrestore(&video->spinlock, flags);

			remove_wait_queue(&video->waitq, &wait);
			set_current_state(TASK_RUNNING);

			frame_prepare(video, video->first_clear_frame);

			n_submit--;
		}

		ret = 0;
		break;
	}

	case DV1394_IOC_WAIT_FRAMES: {
		unsigned int n_wait;

		if ( !video_card_initialized(video) ) {
			ret = -EINVAL;
			goto out;
		}

		n_wait = (unsigned int) arg;

		/* since we re-run the last frame on underflow, we will
		   never actually have n_frames clear frames; at most only
		   n_frames - 1 */

		if (n_wait > (video->n_frames-1) ) {
			ret = -EINVAL;
			goto out;
		}

		add_wait_queue(&video->waitq, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		spin_lock_irqsave(&video->spinlock, flags);

		while (video->n_clear_frames < n_wait) {

			spin_unlock_irqrestore(&video->spinlock, flags);

			if (signal_pending(current)) {
				remove_wait_queue(&video->waitq, &wait);
				set_current_state(TASK_RUNNING);
				ret = -EINTR;
				goto out;
			}

			schedule();
			set_current_state(TASK_INTERRUPTIBLE);

			spin_lock_irqsave(&video->spinlock, flags);
		}

		spin_unlock_irqrestore(&video->spinlock, flags);

		remove_wait_queue(&video->waitq, &wait);
		set_current_state(TASK_RUNNING);
		ret = 0;
		break;
	}

	case DV1394_IOC_RECEIVE_FRAMES: {
		unsigned int n_recv;

		if ( !video_card_initialized(video) ) {
			ret = -EINVAL;
			goto out;
		}

		n_recv = (unsigned int) arg;

		/* at least one frame must be active */
		if (n_recv > (video->n_frames-1) ) {
			ret = -EINVAL;
			goto out;
		}

		spin_lock_irqsave(&video->spinlock, flags);

		/* release the clear frames */
		video->n_clear_frames -= n_recv;

		/* advance the clear frame cursor */
		video->first_clear_frame = (video->first_clear_frame + n_recv) % video->n_frames;

		/* reset dropped_frames */
		video->dropped_frames = 0;

		spin_unlock_irqrestore(&video->spinlock, flags);

		ret = 0;
		break;
	}

	case DV1394_IOC_START_RECEIVE: {
		if ( !video_card_initialized(video) ) {
			ret = do_dv1394_init_default(video);
			if (ret)
				goto out;
		}

		video->continuity_counter = -1;

		receive_packets(video);

		start_dma_receive(video);

		ret = 0;
		break;
	}

	case DV1394_IOC_INIT: {
		struct dv1394_init init;
		if (!argp) {
			ret = do_dv1394_init_default(video);
		} else {
			if (copy_from_user(&init, argp, sizeof(init))) {
				ret = -EFAULT;
				goto out;
			}
			ret = do_dv1394_init(video, &init);
		}
		break;
	}

	case DV1394_IOC_SHUTDOWN:
		do_dv1394_shutdown(video, 0);
		ret = 0;
		break;


        case DV1394_IOC_GET_STATUS: {
		struct dv1394_status status;

		if ( !video_card_initialized(video) ) {
			ret = -EINVAL;
			goto out;
		}

		status.init.api_version = DV1394_API_VERSION;
		status.init.channel = video->channel;
		status.init.n_frames = video->n_frames;
		status.init.format = video->pal_or_ntsc;
		status.init.cip_n = video->cip_n;
		status.init.cip_d = video->cip_d;
		status.init.syt_offset = video->syt_offset;

		status.first_clear_frame = video->first_clear_frame;

		/* the rest of the fields need to be locked against the interrupt */
		spin_lock_irqsave(&video->spinlock, flags);

		status.active_frame = video->active_frame;
		status.n_clear_frames = video->n_clear_frames;

		status.dropped_frames = video->dropped_frames;

		/* reset dropped_frames */
		video->dropped_frames = 0;

		spin_unlock_irqrestore(&video->spinlock, flags);

		if (copy_to_user(argp, &status, sizeof(status))) {
			ret = -EFAULT;
			goto out;
		}

		ret = 0;
		break;
	}

	default:
		break;
	}

 out:
	up(&video->sem);
	unlock_kernel();
	return ret;
}

/*** DEVICE FILE INTERFACE CONTINUED ***************************************/

static int dv1394_open(struct inode *inode, struct file *file)
{
	struct video_card *video = NULL;

	/* if the device was opened through devfs, then file->private_data
	   has already been set to video by devfs */
	if (file->private_data) {
		video = (struct video_card*) file->private_data;

	} else {
		/* look up the card by ID */
		unsigned long flags;

		spin_lock_irqsave(&dv1394_cards_lock, flags);
		if (!list_empty(&dv1394_cards)) {
			struct video_card *p;
			list_for_each_entry(p, &dv1394_cards, list) {
				if ((p->id) == ieee1394_file_to_instance(file)) {
					video = p;
					break;
				}
			}
		}
		spin_unlock_irqrestore(&dv1394_cards_lock, flags);

		if (!video) {
			debug_printk("dv1394: OHCI card %d not found", ieee1394_file_to_instance(file));
			return -ENODEV;
		}

		file->private_data = (void*) video;
	}

#ifndef DV1394_ALLOW_MORE_THAN_ONE_OPEN

	if ( test_and_set_bit(0, &video->open) ) {
		/* video is already open by someone else */
		return -EBUSY;
 	}

#endif

	return 0;
}


static int dv1394_release(struct inode *inode, struct file *file)
{
	struct video_card *video = file_to_video_card(file);

	/* OK to free the DMA buffer, no more mappings can exist */
	do_dv1394_shutdown(video, 1);

	/* clean up async I/O users */
	dv1394_fasync(-1, file, 0);

	/* give someone else a turn */
	clear_bit(0, &video->open);

	return 0;
}


/*** DEVICE DRIVER HANDLERS ************************************************/

static void it_tasklet_func(unsigned long data)
{
	int wake = 0;
	struct video_card *video = (struct video_card*) data;

	spin_lock(&video->spinlock);

	if (!video->dma_running)
		goto out;

	irq_printk("ContextControl = %08x, CommandPtr = %08x\n",
	       reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
	       reg_read(video->ohci, video->ohci_IsoXmitCommandPtr)
	       );


	if ( (video->ohci_it_ctx != -1) &&
	    (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & (1 << 10)) ) {

		struct frame *f;
		unsigned int frame, i;


		if (video->active_frame == -1)
			frame = 0;
		else
			frame = video->active_frame;

		/* check all the DMA-able frames */
		for (i = 0; i < video->n_frames; i++, frame = (frame+1) % video->n_frames) {

			irq_printk("IRQ checking frame %d...", frame);
			f = video->frames[frame];
			if (f->state != FRAME_READY) {
				irq_printk("clear, skipping\n");
				/* we don't own this frame */
				continue;
			}

			irq_printk("DMA\n");

			/* check the frame begin semaphore to see if we can free the previous frame */
			if ( *(f->frame_begin_timestamp) ) {
				int prev_frame;
				struct frame *prev_f;



				/* don't reset, need this later *(f->frame_begin_timestamp) = 0; */
				irq_printk("  BEGIN\n");

				prev_frame = frame - 1;
				if (prev_frame == -1)
					prev_frame += video->n_frames;
				prev_f = video->frames[prev_frame];

				/* make sure we can actually garbage collect
				   this frame */
				if ( (prev_f->state == FRAME_READY) &&
				    prev_f->done && (!f->done) )
				{
					frame_reset(prev_f);
					video->n_clear_frames++;
					wake = 1;
					video->active_frame = frame;

					irq_printk("  BEGIN - freeing previous frame %d, new active frame is %d\n", prev_frame, frame);
				} else {
					irq_printk("  BEGIN - can't free yet\n");
				}

				f->done = 1;
			}


			/* see if we need to set the timestamp for the next frame */
			if ( *(f->mid_frame_timestamp) ) {
				struct frame *next_frame;
				u32 begin_ts, ts_cyc, ts_off;

				*(f->mid_frame_timestamp) = 0;

				begin_ts = le32_to_cpu(*(f->frame_begin_timestamp));

				irq_printk("  MIDDLE - first packet was sent at cycle %4u (%2u), assigned timestamp was (%2u) %4u\n",
					   begin_ts & 0x1FFF, begin_ts & 0xF,
					   f->assigned_timestamp >> 12, f->assigned_timestamp & 0xFFF);

				/* prepare next frame and assign timestamp */
				next_frame = video->frames[ (frame+1) % video->n_frames ];

				if (next_frame->state == FRAME_READY) {
					irq_printk("  MIDDLE - next frame is ready, good\n");
				} else {
					debug_printk("dv1394: Underflow! At least one frame has been dropped.\n");
					next_frame = f;
				}

				/* set the timestamp to the timestamp of the last frame sent,
				   plus the length of the last frame sent, plus the syt latency */
				ts_cyc = begin_ts & 0xF;
				/* advance one frame, plus syt latency (typically 2-3) */
				ts_cyc += f->n_packets + video->syt_offset ;

				ts_off = 0;

				ts_cyc += ts_off/3072;
				ts_off %= 3072;

				next_frame->assigned_timestamp = ((ts_cyc&0xF) << 12) + ts_off;
				if (next_frame->cip_syt1) {
					next_frame->cip_syt1->b[6] = next_frame->assigned_timestamp >> 8;
					next_frame->cip_syt1->b[7] = next_frame->assigned_timestamp & 0xFF;
				}
				if (next_frame->cip_syt2) {
					next_frame->cip_syt2->b[6] = next_frame->assigned_timestamp >> 8;
					next_frame->cip_syt2->b[7] = next_frame->assigned_timestamp & 0xFF;
				}

			}

			/* see if the frame looped */
			if ( *(f->frame_end_timestamp) ) {

				*(f->frame_end_timestamp) = 0;

				debug_printk("  END - the frame looped at least once\n");

				video->dropped_frames++;
			}

		} /* for (each frame) */
	}

	if (wake) {
		kill_fasync(&video->fasync, SIGIO, POLL_OUT);

		/* wake readers/writers/ioctl'ers */
		wake_up_interruptible(&video->waitq);
	}

out:
	spin_unlock(&video->spinlock);
}

static void ir_tasklet_func(unsigned long data)
{
	int wake = 0;
	struct video_card *video = (struct video_card*) data;

	spin_lock(&video->spinlock);

	if (!video->dma_running)
		goto out;

	if ( (video->ohci_ir_ctx != -1) &&
	    (reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & (1 << 10)) ) {

		int sof=0; /* start-of-frame flag */
		struct frame *f;
		u16 packet_length, packet_time;
		int i, dbc=0;
		struct DMA_descriptor_block *block = NULL;
		u16 xferstatus;

		int next_i, prev_i;
		struct DMA_descriptor_block *next = NULL;
		dma_addr_t next_dma = 0;
		struct DMA_descriptor_block *prev = NULL;

		/* loop over all descriptors in all frames */
		for (i = 0; i < video->n_frames*MAX_PACKETS; i++) {
			struct packet *p = dma_region_i(&video->packet_buf, struct packet, video->current_packet);

			/* make sure we are seeing the latest changes to p */
			dma_region_sync_for_cpu(&video->packet_buf,
						(unsigned long) p - (unsigned long) video->packet_buf.kvirt,
						sizeof(struct packet));

			packet_length = le16_to_cpu(p->data_length);
			packet_time   = le16_to_cpu(p->timestamp);

			irq_printk("received packet %02d, timestamp=%04x, length=%04x, sof=%02x%02x\n", video->current_packet,
				   packet_time, packet_length,
				   p->data[0], p->data[1]);

			/* get the descriptor based on packet_buffer cursor */
			f = video->frames[video->current_packet / MAX_PACKETS];
			block = &(f->descriptor_pool[video->current_packet % MAX_PACKETS]);
			xferstatus = le32_to_cpu(block->u.in.il.q[3]) >> 16;
			xferstatus &= 0x1F;
			irq_printk("ir_tasklet_func: xferStatus/resCount [%d] = 0x%08x\n", i, le32_to_cpu(block->u.in.il.q[3]) );

			/* get the current frame */
			f = video->frames[video->active_frame];

			/* exclude empty packet */
			if (packet_length > 8 && xferstatus == 0x11) {
				/* check for start of frame */
				/* DRD> Changed to check section type ([0]>>5==0)
				   and dif sequence ([1]>>4==0) */
				sof = ( (p->data[0] >> 5) == 0 && (p->data[1] >> 4) == 0);

				dbc = (int) (p->cip_h1 >> 24);
				if ( video->continuity_counter != -1 && dbc > ((video->continuity_counter + 1) % 256) )
				{
					printk(KERN_WARNING "dv1394: discontinuity detected, dropping all frames\n" );
					video->dropped_frames += video->n_clear_frames + 1;
					video->first_frame = 0;
					video->n_clear_frames = 0;
					video->first_clear_frame = -1;
				}
				video->continuity_counter = dbc;

				if (!video->first_frame) {
					if (sof) {
						video->first_frame = 1;
					}

				} else if (sof) {
					/* close current frame */
					frame_reset(f);  /* f->state = STATE_CLEAR */
					video->n_clear_frames++;
					if (video->n_clear_frames > video->n_frames) {
						video->dropped_frames++;
						printk(KERN_WARNING "dv1394: dropped a frame during reception\n" );
						video->n_clear_frames = video->n_frames-1;
						video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;
					}
					if (video->first_clear_frame == -1)
						video->first_clear_frame = video->active_frame;

					/* get the next frame */
					video->active_frame = (video->active_frame + 1) % video->n_frames;
					f = video->frames[video->active_frame];
					irq_printk("   frame received, active_frame = %d, n_clear_frames = %d, first_clear_frame = %d\n",
						   video->active_frame, video->n_clear_frames, video->first_clear_frame);
				}
				if (video->first_frame) {
					if (sof) {
						/* open next frame */
						f->state = FRAME_READY;
					}

					/* copy to buffer */
					if (f->n_packets > (video->frame_size / 480)) {
						printk(KERN_ERR "frame buffer overflow during receive\n");
					}

					frame_put_packet(f, p);

				} /* first_frame */
			}

			/* stop, end of ready packets */
			else if (xferstatus == 0) {
				break;
			}

			/* reset xferStatus & resCount */
			block->u.in.il.q[3] = cpu_to_le32(512);

			/* terminate dma chain at this (next) packet */
			next_i = video->current_packet;
			f = video->frames[next_i / MAX_PACKETS];
			next = &(f->descriptor_pool[next_i % MAX_PACKETS]);
			next_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;
			next->u.in.il.q[0] |= 3 << 20; /* enable interrupt */
			next->u.in.il.q[2] = 0; /* disable branch */

			/* link previous to next */
			prev_i = (next_i == 0) ? (MAX_PACKETS * video->n_frames - 1) : (next_i - 1);
			f = video->frames[prev_i / MAX_PACKETS];
			prev = &(f->descriptor_pool[prev_i % MAX_PACKETS]);
			if (prev_i % (MAX_PACKETS/2)) {
				prev->u.in.il.q[0] &= ~(3 << 20); /* no interrupt */
			} else {
				prev->u.in.il.q[0] |= 3 << 20; /* enable interrupt */
			}
			prev->u.in.il.q[2] = cpu_to_le32(next_dma | 1); /* set Z=1 */
			wmb();

			/* wake up DMA in case it fell asleep */
			reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));

			/* advance packet_buffer cursor */
			video->current_packet = (video->current_packet + 1) % (MAX_PACKETS * video->n_frames);

		} /* for all packets */

		wake = 1; /* why the hell not? */

	} /* receive interrupt */

	if (wake) {
		kill_fasync(&video->fasync, SIGIO, POLL_IN);

		/* wake readers/writers/ioctl'ers */
		wake_up_interruptible(&video->waitq);
	}

out:
	spin_unlock(&video->spinlock);
}

static struct cdev dv1394_cdev;
static struct file_operations dv1394_fops=
{
	.owner =	THIS_MODULE,
	.poll =         dv1394_poll,
	.unlocked_ioctl = dv1394_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = dv1394_compat_ioctl,
#endif
	.mmap =		dv1394_mmap,
	.open =		dv1394_open,
	.write =        dv1394_write,
	.read =         dv1394_read,
	.release =	dv1394_release,
	.fasync =       dv1394_fasync,
};


/*** HOTPLUG STUFF **********************************************************/
/*
 * Export information about protocols/devices supported by this driver.
 */
static struct ieee1394_device_id dv1394_id_table[] = {
	{
		.match_flags	= IEEE1394_MATCH_SPECIFIER_ID | IEEE1394_MATCH_VERSION,
		.specifier_id	= AVC_UNIT_SPEC_ID_ENTRY & 0xffffff,
		.version	= AVC_SW_VERSION_ENTRY & 0xffffff
	},
	{ }
};

MODULE_DEVICE_TABLE(ieee1394, dv1394_id_table);

static struct hpsb_protocol_driver dv1394_driver = {
	.name		= "DV/1394 Driver",
	.id_table	= dv1394_id_table,
	.driver         = {
		.name	= "dv1394",
		.bus	= &ieee1394_bus_type,
	},
};


/*** IEEE1394 HPSB CALLBACKS ***********************************************/

static int dv1394_init(struct ti_ohci *ohci, enum pal_or_ntsc format, enum modes mode)
{
	struct video_card *video;
	unsigned long flags;
	int i;

	video = kmalloc(sizeof(struct video_card), GFP_KERNEL);
	if (!video) {
		printk(KERN_ERR "dv1394: cannot allocate video_card\n");
		goto err;
	}

	memset(video, 0, sizeof(struct video_card));

	video->ohci = ohci;
	/* lower 2 bits of id indicate which of four "plugs"
	   per host */
	video->id = ohci->host->id << 2;
	if (format == DV1394_NTSC)
		video->id |= mode;
	else
		video->id |= 2 + mode;

	video->ohci_it_ctx = -1;
	video->ohci_ir_ctx = -1;

	video->ohci_IsoXmitContextControlSet = 0;
	video->ohci_IsoXmitContextControlClear = 0;
	video->ohci_IsoXmitCommandPtr = 0;

	video->ohci_IsoRcvContextControlSet = 0;
	video->ohci_IsoRcvContextControlClear = 0;
	video->ohci_IsoRcvCommandPtr = 0;
	video->ohci_IsoRcvContextMatch = 0;

	video->n_frames = 0; /* flag that video is not initialized */
	video->channel = 63; /* default to broadcast channel */
	video->active_frame = -1;

	/* initialize the following */
	video->pal_or_ntsc = format;
	video->cip_n = 0; /* 0 = use builtin default */
	video->cip_d = 0;
	video->syt_offset = 0;
	video->mode = mode;

	for (i = 0; i < DV1394_MAX_FRAMES; i++)
		video->frames[i] = NULL;

	dma_region_init(&video->dv_buf);
	video->dv_buf_size = 0;
	dma_region_init(&video->packet_buf);
	video->packet_buf_size = 0;

	clear_bit(0, &video->open);
	spin_lock_init(&video->spinlock);
	video->dma_running = 0;
	init_MUTEX(&video->sem);
	init_waitqueue_head(&video->waitq);
	video->fasync = NULL;

	spin_lock_irqsave(&dv1394_cards_lock, flags);
	INIT_LIST_HEAD(&video->list);
	list_add_tail(&video->list, &dv1394_cards);
	spin_unlock_irqrestore(&dv1394_cards_lock, flags);

	if (devfs_mk_cdev(MKDEV(IEEE1394_MAJOR,
				IEEE1394_MINOR_BLOCK_DV1394*16 + video->id),
			S_IFCHR|S_IRUGO|S_IWUGO,
			 "ieee1394/dv/host%d/%s/%s",
			 (video->id>>2),
			 (video->pal_or_ntsc == DV1394_NTSC ? "NTSC" : "PAL"),
			 (video->mode == MODE_RECEIVE ? "in" : "out")) < 0)
			goto err_free;

	debug_printk("dv1394: dv1394_init() OK on ID %d\n", video->id);

	return 0;

 err_free:
	kfree(video);
 err:
	return -1;
}

static void dv1394_un_init(struct video_card *video)
{
	char buf[32];

	/* obviously nobody has the driver open at this point */
	do_dv1394_shutdown(video, 1);
	snprintf(buf, sizeof(buf), "dv/host%d/%s/%s", (video->id >> 2),
		(video->pal_or_ntsc == DV1394_NTSC ? "NTSC" : "PAL"),
		(video->mode == MODE_RECEIVE ? "in" : "out")
		);

	devfs_remove("ieee1394/%s", buf);
	kfree(video);
}


static void dv1394_remove_host (struct hpsb_host *host)
{
	struct video_card *video;
	unsigned long flags;
	int id = host->id;

	/* We only work with the OHCI-1394 driver */
	if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
		return;

	/* find the corresponding video_cards */
	do {
		struct video_card *tmp_vid;

		video = NULL;

		spin_lock_irqsave(&dv1394_cards_lock, flags);
		list_for_each_entry(tmp_vid, &dv1394_cards, list) {
			if ((tmp_vid->id >> 2) == id) {
				list_del(&tmp_vid->list);
				video = tmp_vid;
				break;
			}
		}
		spin_unlock_irqrestore(&dv1394_cards_lock, flags);

		if (video)
			dv1394_un_init(video);
	} while (video != NULL);

	class_device_destroy(hpsb_protocol_class,
		MKDEV(IEEE1394_MAJOR, IEEE1394_MINOR_BLOCK_DV1394 * 16 + (id<<2)));
	devfs_remove("ieee1394/dv/host%d/NTSC", id);
	devfs_remove("ieee1394/dv/host%d/PAL", id);
	devfs_remove("ieee1394/dv/host%d", id);
}

static void dv1394_add_host (struct hpsb_host *host)
{
	struct ti_ohci *ohci;
	int id = host->id;

	/* We only work with the OHCI-1394 driver */
	if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
		return;

	ohci = (struct ti_ohci *)host->hostdata;

	class_device_create(hpsb_protocol_class, NULL, MKDEV(
		IEEE1394_MAJOR,	IEEE1394_MINOR_BLOCK_DV1394 * 16 + (id<<2)), 
		NULL, "dv1394-%d", id);
	devfs_mk_dir("ieee1394/dv/host%d", id);
	devfs_mk_dir("ieee1394/dv/host%d/NTSC", id);
	devfs_mk_dir("ieee1394/dv/host%d/PAL", id);

	dv1394_init(ohci, DV1394_NTSC, MODE_RECEIVE);
	dv1394_init(ohci, DV1394_NTSC, MODE_TRANSMIT);
	dv1394_init(ohci, DV1394_PAL, MODE_RECEIVE);
	dv1394_init(ohci, DV1394_PAL, MODE_TRANSMIT);
}


/* Bus reset handler. In the event of a bus reset, we may need to
   re-start the DMA contexts - otherwise the user program would
   end up waiting forever.
*/

static void dv1394_host_reset(struct hpsb_host *host)
{
	struct ti_ohci *ohci;
	struct video_card *video = NULL, *tmp_vid;
	unsigned long flags;

	/* We only work with the OHCI-1394 driver */
	if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
		return;

	ohci = (struct ti_ohci *)host->hostdata;


	/* find the corresponding video_cards */
	spin_lock_irqsave(&dv1394_cards_lock, flags);
	list_for_each_entry(tmp_vid, &dv1394_cards, list) {
		if ((tmp_vid->id >> 2) == host->id) {
			video = tmp_vid;
			break;
		}
	}
	spin_unlock_irqrestore(&dv1394_cards_lock, flags);

	if (!video)
		return;


	spin_lock_irqsave(&video->spinlock, flags);

	if (!video->dma_running)
		goto out;

	/* check IT context */
	if (video->ohci_it_ctx != -1) {
		u32 ctx;

		ctx = reg_read(video->ohci, video->ohci_IsoXmitContextControlSet);

		/* if (RUN but not ACTIVE) */
		if ( (ctx & (1<<15)) &&
		    !(ctx & (1<<10)) ) {

			debug_printk("dv1394: IT context stopped due to bus reset; waking it up\n");

			/* to be safe, assume a frame has been dropped. User-space programs
			   should handle this condition like an underflow. */
			video->dropped_frames++;

			/* for some reason you must clear, then re-set the RUN bit to restart DMA */

			/* clear RUN */
			reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, (1 << 15));
			flush_pci_write(video->ohci);

			/* set RUN */
			reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, (1 << 15));
			flush_pci_write(video->ohci);

			/* set the WAKE bit (just in case; this isn't strictly necessary) */
			reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, (1 << 12));
			flush_pci_write(video->ohci);

			irq_printk("dv1394: AFTER IT restart ctx 0x%08x ptr 0x%08x\n",
				   reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
				   reg_read(video->ohci, video->ohci_IsoXmitCommandPtr));
		}
	}

	/* check IR context */
	if (video->ohci_ir_ctx != -1) {
		u32 ctx;

		ctx = reg_read(video->ohci, video->ohci_IsoRcvContextControlSet);

		/* if (RUN but not ACTIVE) */
		if ( (ctx & (1<<15)) &&
		    !(ctx & (1<<10)) ) {

			debug_printk("dv1394: IR context stopped due to bus reset; waking it up\n");

			/* to be safe, assume a frame has been dropped. User-space programs
			   should handle this condition like an overflow. */
			video->dropped_frames++;

			/* for some reason you must clear, then re-set the RUN bit to restart DMA */
			/* XXX this doesn't work for me, I can't get IR DMA to restart :[ */

			/* clear RUN */
			reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, (1 << 15));
			flush_pci_write(video->ohci);

			/* set RUN */
			reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 15));
			flush_pci_write(video->ohci);

			/* set the WAKE bit (just in case; this isn't strictly necessary) */
			reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));
			flush_pci_write(video->ohci);

			irq_printk("dv1394: AFTER IR restart ctx 0x%08x ptr 0x%08x\n",
				   reg_read(video->ohci, video->ohci_IsoRcvContextControlSet),
				   reg_read(video->ohci, video->ohci_IsoRcvCommandPtr));
		}
	}

out:
	spin_unlock_irqrestore(&video->spinlock, flags);

	/* wake readers/writers/ioctl'ers */
	wake_up_interruptible(&video->waitq);
}

static struct hpsb_highlevel dv1394_highlevel = {
	.name =		"dv1394",
	.add_host =	dv1394_add_host,
	.remove_host =	dv1394_remove_host,
	.host_reset =   dv1394_host_reset,
};

#ifdef CONFIG_COMPAT

#define DV1394_IOC32_INIT       _IOW('#', 0x06, struct dv1394_init32)
#define DV1394_IOC32_GET_STATUS _IOR('#', 0x0c, struct dv1394_status32)

struct dv1394_init32 {
	u32 api_version;
	u32 channel;
	u32 n_frames;
	u32 format;
	u32 cip_n;
	u32 cip_d;
	u32 syt_offset;
};

struct dv1394_status32 {
	struct dv1394_init32 init;
	s32 active_frame;
	u32 first_clear_frame;
	u32 n_clear_frames;
	u32 dropped_frames;
};

/* RED-PEN: this should use compat_alloc_userspace instead */

static int handle_dv1394_init(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct dv1394_init32 dv32;
	struct dv1394_init dv;
	mm_segment_t old_fs;
	int ret;

	if (file->f_op->unlocked_ioctl != dv1394_ioctl)
		return -EFAULT;

	if (copy_from_user(&dv32, (void __user *)arg, sizeof(dv32)))
		return -EFAULT;

	dv.api_version = dv32.api_version;
	dv.channel = dv32.channel;
	dv.n_frames = dv32.n_frames;
	dv.format = dv32.format;
	dv.cip_n = (unsigned long)dv32.cip_n;
	dv.cip_d = (unsigned long)dv32.cip_d;
	dv.syt_offset = dv32.syt_offset;

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	ret = dv1394_ioctl(file, DV1394_IOC_INIT, (unsigned long)&dv);
	set_fs(old_fs);

	return ret;
}

static int handle_dv1394_get_status(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct dv1394_status32 dv32;
	struct dv1394_status dv;
	mm_segment_t old_fs;
	int ret;

	if (file->f_op->unlocked_ioctl != dv1394_ioctl)
		return -EFAULT;

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	ret = dv1394_ioctl(file, DV1394_IOC_GET_STATUS, (unsigned long)&dv);
	set_fs(old_fs);

	if (!ret) {
		dv32.init.api_version = dv.init.api_version;
		dv32.init.channel = dv.init.channel;
		dv32.init.n_frames = dv.init.n_frames;
		dv32.init.format = dv.init.format;
		dv32.init.cip_n = (u32)dv.init.cip_n;
		dv32.init.cip_d = (u32)dv.init.cip_d;
		dv32.init.syt_offset = dv.init.syt_offset;
		dv32.active_frame = dv.active_frame;
		dv32.first_clear_frame = dv.first_clear_frame;
		dv32.n_clear_frames = dv.n_clear_frames;
		dv32.dropped_frames = dv.dropped_frames;

		if (copy_to_user((struct dv1394_status32 __user *)arg, &dv32, sizeof(dv32)))
			ret = -EFAULT;
	}

	return ret;
}



static long dv1394_compat_ioctl(struct file *file, unsigned int cmd,
			       unsigned long arg)
{
	switch (cmd) {
	case DV1394_IOC_SHUTDOWN:
	case DV1394_IOC_SUBMIT_FRAMES:
	case DV1394_IOC_WAIT_FRAMES:
	case DV1394_IOC_RECEIVE_FRAMES:
	case DV1394_IOC_START_RECEIVE:
		return dv1394_ioctl(file, cmd, arg);

	case DV1394_IOC32_INIT:
		return handle_dv1394_init(file, cmd, arg);
	case DV1394_IOC32_GET_STATUS:
		return handle_dv1394_get_status(file, cmd, arg);
	default:
		return -ENOIOCTLCMD;
	}
}

#endif /* CONFIG_COMPAT */


/*** KERNEL MODULE HANDLERS ************************************************/

MODULE_AUTHOR("Dan Maas <dmaas@dcine.com>, Dan Dennedy <dan@dennedy.org>");
MODULE_DESCRIPTION("driver for DV input/output on OHCI board");
MODULE_SUPPORTED_DEVICE("dv1394");
MODULE_LICENSE("GPL");

static void __exit dv1394_exit_module(void)
{
	hpsb_unregister_protocol(&dv1394_driver);

	hpsb_unregister_highlevel(&dv1394_highlevel);
	cdev_del(&dv1394_cdev);
	devfs_remove("ieee1394/dv");
}

static int __init dv1394_init_module(void)
{
	int ret;

	cdev_init(&dv1394_cdev, &dv1394_fops);
	dv1394_cdev.owner = THIS_MODULE;
	kobject_set_name(&dv1394_cdev.kobj, "dv1394");
	ret = cdev_add(&dv1394_cdev, IEEE1394_DV1394_DEV, 16);
	if (ret) {
		printk(KERN_ERR "dv1394: unable to register character device\n");
		return ret;
	}

	devfs_mk_dir("ieee1394/dv");

	hpsb_register_highlevel(&dv1394_highlevel);

	ret = hpsb_register_protocol(&dv1394_driver);
	if (ret) {
		printk(KERN_ERR "dv1394: failed to register protocol\n");
		hpsb_unregister_highlevel(&dv1394_highlevel);
		devfs_remove("ieee1394/dv");
		cdev_del(&dv1394_cdev);
		return ret;
	}

	return 0;
}

module_init(dv1394_init_module);
module_exit(dv1394_exit_module);