aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/ide/pci/cmd640.c
blob: 29fbc5ead03b85851855f83c9683655a6c7f913d (plain) (blame)
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
/*
 *  Copyright (C) 1995-1996  Linus Torvalds & authors (see below)
 */

/*
 *  Original authors:	abramov@cecmow.enet.dec.com (Igor Abramov)
 *  			mlord@pobox.com (Mark Lord)
 *
 *  See linux/MAINTAINERS for address of current maintainer.
 *
 *  This file provides support for the advanced features and bugs
 *  of IDE interfaces using the CMD Technologies 0640 IDE interface chip.
 *
 *  These chips are basically fucked by design, and getting this driver
 *  to work on every motherboard design that uses this screwed chip seems
 *  bloody well impossible.  However, we're still trying.
 *
 *  Version 0.97 worked for everybody.
 *
 *  User feedback is essential.  Many thanks to the beta test team:
 *
 *  A.Hartgers@stud.tue.nl, JZDQC@CUNYVM.CUNY.edu, abramov@cecmow.enet.dec.com,
 *  bardj@utopia.ppp.sn.no, bart@gaga.tue.nl, bbol001@cs.auckland.ac.nz,
 *  chrisc@dbass.demon.co.uk, dalecki@namu26.Num.Math.Uni-Goettingen.de,
 *  derekn@vw.ece.cmu.edu, florian@btp2x3.phy.uni-bayreuth.de,
 *  flynn@dei.unipd.it, gadio@netvision.net.il, godzilla@futuris.net,
 *  j@pobox.com, jkemp1@mises.uni-paderborn.de, jtoppe@hiwaay.net,
 *  kerouac@ssnet.com, meskes@informatik.rwth-aachen.de, hzoli@cs.elte.hu,
 *  peter@udgaard.isgtec.com, phil@tazenda.demon.co.uk, roadcapw@cfw.com,
 *  s0033las@sun10.vsz.bme.hu, schaffer@tam.cornell.edu, sjd@slip.net,
 *  steve@ei.org, ulrpeg@bigcomm.gun.de, ism@tardis.ed.ac.uk, mack@cray.com
 *  liug@mama.indstate.edu, and others.
 *
 *  Version 0.01	Initial version, hacked out of ide.c,
 *			and #include'd rather than compiled separately.
 *			This will get cleaned up in a subsequent release.
 *
 *  Version 0.02	Fixes for vlb initialization code, enable prefetch
 *			for versions 'B' and 'C' of chip by default,
 *			some code cleanup.
 *
 *  Version 0.03	Added reset of secondary interface,
 *			and black list for devices which are not compatible
 *			with prefetch mode. Separate function for setting
 *			prefetch is added, possibly it will be called some
 *			day from ioctl processing code.
 *
 *  Version 0.04	Now configs/compiles separate from ide.c
 *
 *  Version 0.05	Major rewrite of interface timing code.
 *			Added new function cmd640_set_mode to set PIO mode
 *			from ioctl call. New drives added to black list.
 *
 *  Version 0.06	More code cleanup. Prefetch is enabled only for
 *			detected hard drives, not included in prefetch
 *			black list.
 *
 *  Version 0.07	Changed to more conservative drive tuning policy.
 *			Unknown drives, which report PIO < 4 are set to
 *			(reported_PIO - 1) if it is supported, or to PIO0.
 *			List of known drives extended by info provided by
 *			CMD at their ftp site.
 *
 *  Version 0.08	Added autotune/noautotune support.
 *
 *  Version 0.09	Try to be smarter about 2nd port enabling.
 *  Version 0.10	Be nice and don't reset 2nd port.
 *  Version 0.11	Try to handle more weird situations.
 *
 *  Version 0.12	Lots of bug fixes from Laszlo Peter
 *			irq unmasking disabled for reliability.
 *			try to be even smarter about the second port.
 *			tidy up source code formatting.
 *  Version 0.13	permit irq unmasking again.
 *  Version 0.90	massive code cleanup, some bugs fixed.
 *			defaults all drives to PIO mode0, prefetch off.
 *			autotune is OFF by default, with compile time flag.
 *			prefetch can be turned OFF/ON using "hdparm -p8/-p9"
 *			 (requires hdparm-3.1 or newer)
 *  Version 0.91	first release to linux-kernel list.
 *  Version 0.92	move initial reg dump to separate callable function
 *			change "readahead" to "prefetch" to avoid confusion
 *  Version 0.95	respect original BIOS timings unless autotuning.
 *			tons of code cleanup and rearrangement.
 *			added CONFIG_BLK_DEV_CMD640_ENHANCED option
 *			prevent use of unmask when prefetch is on
 *  Version 0.96	prevent use of io_32bit when prefetch is off
 *  Version 0.97	fix VLB secondary interface for sjd@slip.net
 *			other minor tune-ups:  0.96 was very good.
 *  Version 0.98	ignore PCI version when disabled by BIOS
 *  Version 0.99	display setup/active/recovery clocks with PIO mode
 *  Version 1.00	Mmm.. cannot depend on PCMD_ENA in all systems
 *  Version 1.01	slow/fast devsel can be selected with "hdparm -p6/-p7"
 *			 ("fast" is necessary for 32bit I/O in some systems)
 *  Version 1.02	fix bug that resulted in slow "setup times"
 *			 (patch courtesy of Zoltan Hidvegi)
 */

#define CMD640_PREFETCH_MASKS 1

//#define CMD640_DUMP_REGS

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/hdreg.h>
#include <linux/ide.h>
#include <linux/init.h>

#include <asm/io.h>

/*
 * This flag is set in ide.c by the parameter:  ide0=cmd640_vlb
 */
int cmd640_vlb = 0;

/*
 * CMD640 specific registers definition.
 */

#define VID		0x00
#define DID		0x02
#define PCMD		0x04
#define   PCMD_ENA	0x01
#define PSTTS		0x06
#define REVID		0x08
#define PROGIF		0x09
#define SUBCL		0x0a
#define BASCL		0x0b
#define BaseA0		0x10
#define BaseA1		0x14
#define BaseA2		0x18
#define BaseA3		0x1c
#define INTLINE		0x3c
#define INPINE		0x3d

#define	CFR		0x50
#define   CFR_DEVREV		0x03
#define   CFR_IDE01INTR		0x04
#define	  CFR_DEVID		0x18
#define	  CFR_AT_VESA_078h	0x20
#define	  CFR_DSA1		0x40
#define	  CFR_DSA0		0x80

#define CNTRL		0x51
#define	  CNTRL_DIS_RA0		0x40
#define   CNTRL_DIS_RA1		0x80
#define	  CNTRL_ENA_2ND		0x08

#define	CMDTIM		0x52
#define	ARTTIM0		0x53
#define	DRWTIM0		0x54
#define ARTTIM1 	0x55
#define DRWTIM1		0x56
#define ARTTIM23	0x57
#define   ARTTIM23_DIS_RA2	0x04
#define   ARTTIM23_DIS_RA3	0x08
#define DRWTIM23	0x58
#define BRST		0x59

/*
 * Registers and masks for easy access by drive index:
 */
static u8 prefetch_regs[4]  = {CNTRL, CNTRL, ARTTIM23, ARTTIM23};
static u8 prefetch_masks[4] = {CNTRL_DIS_RA0, CNTRL_DIS_RA1, ARTTIM23_DIS_RA2, ARTTIM23_DIS_RA3};

#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED

static u8 arttim_regs[4] = {ARTTIM0, ARTTIM1, ARTTIM23, ARTTIM23};
static u8 drwtim_regs[4] = {DRWTIM0, DRWTIM1, DRWTIM23, DRWTIM23};

/*
 * Current cmd640 timing values for each drive.
 * The defaults for each are the slowest possible timings.
 */
static u8 setup_counts[4]    = {4, 4, 4, 4};     /* Address setup count (in clocks) */
static u8 active_counts[4]   = {16, 16, 16, 16}; /* Active count   (encoded) */
static u8 recovery_counts[4] = {16, 16, 16, 16}; /* Recovery count (encoded) */

#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */

static DEFINE_SPINLOCK(cmd640_lock);

/*
 * These are initialized to point at the devices we control
 */
static ide_hwif_t  *cmd_hwif0, *cmd_hwif1;
static ide_drive_t *cmd_drives[4];

/*
 * Interface to access cmd640x registers
 */
static unsigned int cmd640_key;
static void (*__put_cmd640_reg)(u16 reg, u8 val);
static u8 (*__get_cmd640_reg)(u16 reg);

/*
 * This is read from the CFR reg, and is used in several places.
 */
static unsigned int cmd640_chip_version;

/*
 * The CMD640x chip does not support DWORD config write cycles, but some
 * of the BIOSes use them to implement the config services.
 * Therefore, we must use direct IO instead.
 */

/* PCI method 1 access */

static void put_cmd640_reg_pci1 (u16 reg, u8 val)
{
	outl_p((reg & 0xfc) | cmd640_key, 0xcf8);
	outb_p(val, (reg & 3) | 0xcfc);
}

static u8 get_cmd640_reg_pci1 (u16 reg)
{
	outl_p((reg & 0xfc) | cmd640_key, 0xcf8);
	return inb_p((reg & 3) | 0xcfc);
}

/* PCI method 2 access (from CMD datasheet) */

static void put_cmd640_reg_pci2 (u16 reg, u8 val)
{
	outb_p(0x10, 0xcf8);
	outb_p(val, cmd640_key + reg);
	outb_p(0, 0xcf8);
}

static u8 get_cmd640_reg_pci2 (u16 reg)
{
	u8 b;

	outb_p(0x10, 0xcf8);
	b = inb_p(cmd640_key + reg);
	outb_p(0, 0xcf8);
	return b;
}

/* VLB access */

static void put_cmd640_reg_vlb (u16 reg, u8 val)
{
	outb_p(reg, cmd640_key);
	outb_p(val, cmd640_key + 4);
}

static u8 get_cmd640_reg_vlb (u16 reg)
{
	outb_p(reg, cmd640_key);
	return inb_p(cmd640_key + 4);
}

static u8 get_cmd640_reg(u16 reg)
{
	unsigned long flags;
	u8 b;

	spin_lock_irqsave(&cmd640_lock, flags);
	b = __get_cmd640_reg(reg);
	spin_unlock_irqrestore(&cmd640_lock, flags);
	return b;
}

static void put_cmd640_reg(u16 reg, u8 val)
{
	unsigned long flags;

	spin_lock_irqsave(&cmd640_lock, flags);
	__put_cmd640_reg(reg,val);
	spin_unlock_irqrestore(&cmd640_lock, flags);
}

static int __init match_pci_cmd640_device (void)
{
	const u8 ven_dev[4] = {0x95, 0x10, 0x40, 0x06};
	unsigned int i;
	for (i = 0; i < 4; i++) {
		if (get_cmd640_reg(i) != ven_dev[i])
			return 0;
	}
#ifdef STUPIDLY_TRUST_BROKEN_PCMD_ENA_BIT
	if ((get_cmd640_reg(PCMD) & PCMD_ENA) == 0) {
		printk("ide: cmd640 on PCI disabled by BIOS\n");
		return 0;
	}
#endif /* STUPIDLY_TRUST_BROKEN_PCMD_ENA_BIT */
	return 1; /* success */
}

/*
 * Probe for CMD640x -- pci method 1
 */
static int __init probe_for_cmd640_pci1 (void)
{
	__get_cmd640_reg = get_cmd640_reg_pci1;
	__put_cmd640_reg = put_cmd640_reg_pci1;
	for (cmd640_key = 0x80000000;
	     cmd640_key <= 0x8000f800;
	     cmd640_key += 0x800) {
		if (match_pci_cmd640_device())
			return 1; /* success */
	}
	return 0;
}

/*
 * Probe for CMD640x -- pci method 2
 */
static int __init probe_for_cmd640_pci2 (void)
{
	__get_cmd640_reg = get_cmd640_reg_pci2;
	__put_cmd640_reg = put_cmd640_reg_pci2;
	for (cmd640_key = 0xc000; cmd640_key <= 0xcf00; cmd640_key += 0x100) {
		if (match_pci_cmd640_device())
			return 1; /* success */
	}
	return 0;
}

/*
 * Probe for CMD640x -- vlb
 */
static int __init probe_for_cmd640_vlb (void)
{
	u8 b;

	__get_cmd640_reg = get_cmd640_reg_vlb;
	__put_cmd640_reg = put_cmd640_reg_vlb;
	cmd640_key = 0x178;
	b = get_cmd640_reg(CFR);
	if (b == 0xff || b == 0x00 || (b & CFR_AT_VESA_078h)) {
		cmd640_key = 0x78;
		b = get_cmd640_reg(CFR);
		if (b == 0xff || b == 0x00 || !(b & CFR_AT_VESA_078h))
			return 0;
	}
	return 1; /* success */
}

/*
 *  Returns 1 if an IDE interface/drive exists at 0x170,
 *  Returns 0 otherwise.
 */
static int __init secondary_port_responding (void)
{
	unsigned long flags;

	spin_lock_irqsave(&cmd640_lock, flags);

	outb_p(0x0a, 0x170 + IDE_SELECT_OFFSET);	/* select drive0 */
	udelay(100);
	if ((inb_p(0x170 + IDE_SELECT_OFFSET) & 0x1f) != 0x0a) {
		outb_p(0x1a, 0x170 + IDE_SELECT_OFFSET); /* select drive1 */
		udelay(100);
		if ((inb_p(0x170 + IDE_SELECT_OFFSET) & 0x1f) != 0x1a) {
			spin_unlock_irqrestore(&cmd640_lock, flags);
			return 0; /* nothing responded */
		}
	}
	spin_unlock_irqrestore(&cmd640_lock, flags);
	return 1; /* success */
}

#ifdef CMD640_DUMP_REGS
/*
 * Dump out all cmd640 registers.  May be called from ide.c
 */
static void cmd640_dump_regs (void)
{
	unsigned int reg = cmd640_vlb ? 0x50 : 0x00;

	/* Dump current state of chip registers */
	printk("ide: cmd640 internal register dump:");
	for (; reg <= 0x59; reg++) {
		if (!(reg & 0x0f))
			printk("\n%04x:", reg);
		printk(" %02x", get_cmd640_reg(reg));
	}
	printk("\n");
}
#endif

/*
 * Check whether prefetch is on for a drive,
 * and initialize the unmask flags for safe operation.
 */
static void __init check_prefetch (unsigned int index)
{
	ide_drive_t *drive = cmd_drives[index];
	u8 b = get_cmd640_reg(prefetch_regs[index]);

	if (b & prefetch_masks[index]) {	/* is prefetch off? */
		drive->no_unmask = 0;
		drive->no_io_32bit = 1;
		drive->io_32bit = 0;
	} else {
#if CMD640_PREFETCH_MASKS
		drive->no_unmask = 1;
		drive->unmask = 0;
#endif
		drive->no_io_32bit = 0;
	}
}

/*
 * Figure out which devices we control
 */
static void __init setup_device_ptrs (void)
{
	unsigned int i;

	cmd_hwif0 = &ide_hwifs[0]; /* default, if not found below */
	cmd_hwif1 = &ide_hwifs[1]; /* default, if not found below */
	for (i = 0; i < MAX_HWIFS; i++) {
		ide_hwif_t *hwif = &ide_hwifs[i];
		if (hwif->chipset == ide_unknown || hwif->chipset == ide_forced) {
			if (hwif->io_ports[IDE_DATA_OFFSET] == 0x1f0)
				cmd_hwif0 = hwif;
			else if (hwif->io_ports[IDE_DATA_OFFSET] == 0x170)
				cmd_hwif1 = hwif;
		}
	}
	cmd_drives[0] = &cmd_hwif0->drives[0];
	cmd_drives[1] = &cmd_hwif0->drives[1];
	cmd_drives[2] = &cmd_hwif1->drives[0];
	cmd_drives[3] = &cmd_hwif1->drives[1];
}

#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED

/*
 * Sets prefetch mode for a drive.
 */
static void set_prefetch_mode (unsigned int index, int mode)
{
	ide_drive_t *drive = cmd_drives[index];
	unsigned long flags;
	int reg = prefetch_regs[index];
	u8 b;

	spin_lock_irqsave(&cmd640_lock, flags);
	b = __get_cmd640_reg(reg);
	if (mode) {	/* want prefetch on? */
#if CMD640_PREFETCH_MASKS
		drive->no_unmask = 1;
		drive->unmask = 0;
#endif
		drive->no_io_32bit = 0;
		b &= ~prefetch_masks[index];	/* enable prefetch */
	} else {
		drive->no_unmask = 0;
		drive->no_io_32bit = 1;
		drive->io_32bit = 0;
		b |= prefetch_masks[index];	/* disable prefetch */
	}
	__put_cmd640_reg(reg, b);
	spin_unlock_irqrestore(&cmd640_lock, flags);
}

/*
 * Dump out current drive clocks settings
 */
static void display_clocks (unsigned int index)
{
	u8 active_count, recovery_count;

	active_count = active_counts[index];
	if (active_count == 1)
		++active_count;
	recovery_count = recovery_counts[index];
	if (active_count > 3 && recovery_count == 1)
		++recovery_count;
	if (cmd640_chip_version > 1)
		recovery_count += 1;  /* cmd640b uses (count + 1)*/
	printk(", clocks=%d/%d/%d\n", setup_counts[index], active_count, recovery_count);
}

/*
 * Pack active and recovery counts into single byte representation
 * used by controller
 */
static inline u8 pack_nibbles (u8 upper, u8 lower)
{
	return ((upper & 0x0f) << 4) | (lower & 0x0f);
}

/*
 * This routine retrieves the initial drive timings from the chipset.
 */
static void __init retrieve_drive_counts (unsigned int index)
{
	u8 b;

	/*
	 * Get the internal setup timing, and convert to clock count
	 */
	b = get_cmd640_reg(arttim_regs[index]) & ~0x3f;
	switch (b) {
		case 0x00: b = 4; break;
		case 0x80: b = 3; break;
		case 0x40: b = 2; break;
		default:   b = 5; break;
	}
	setup_counts[index] = b;

	/*
	 * Get the active/recovery counts
	 */
	b = get_cmd640_reg(drwtim_regs[index]);
	active_counts[index]   = (b >> 4)   ? (b >> 4)   : 0x10;
	recovery_counts[index] = (b & 0x0f) ? (b & 0x0f) : 0x10;
}


/*
 * This routine writes the prepared setup/active/recovery counts
 * for a drive into the cmd640 chipset registers to active them.
 */
static void program_drive_counts (unsigned int index)
{
	unsigned long flags;
	u8 setup_count    = setup_counts[index];
	u8 active_count   = active_counts[index];
	u8 recovery_count = recovery_counts[index];

	/*
	 * Set up address setup count and drive read/write timing registers.
	 * Primary interface has individual count/timing registers for
	 * each drive.  Secondary interface has one common set of registers,
	 * so we merge the timings, using the slowest value for each timing.
	 */
	if (index > 1) {
		unsigned int mate;
		if (cmd_drives[mate = index ^ 1]->present) {
			if (setup_count < setup_counts[mate])
				setup_count = setup_counts[mate];
			if (active_count < active_counts[mate])
				active_count = active_counts[mate];
			if (recovery_count < recovery_counts[mate])
				recovery_count = recovery_counts[mate];
		}
	}

	/*
	 * Convert setup_count to internal chipset representation
	 */
	switch (setup_count) {
		case 4:	 setup_count = 0x00; break;
		case 3:	 setup_count = 0x80; break;
		case 1:
		case 2:	 setup_count = 0x40; break;
		default: setup_count = 0xc0; /* case 5 */
	}

	/*
	 * Now that everything is ready, program the new timings
	 */
	spin_lock_irqsave(&cmd640_lock, flags);
	/*
	 * Program the address_setup clocks into ARTTIM reg,
	 * and then the active/recovery counts into the DRWTIM reg
	 * (this converts counts of 16 into counts of zero -- okay).
	 */
	setup_count |= __get_cmd640_reg(arttim_regs[index]) & 0x3f;
	__put_cmd640_reg(arttim_regs[index], setup_count);
	__put_cmd640_reg(drwtim_regs[index], pack_nibbles(active_count, recovery_count));
	spin_unlock_irqrestore(&cmd640_lock, flags);
}

/*
 * Set a specific pio_mode for a drive
 */
static void cmd640_set_mode (unsigned int index, u8 pio_mode, unsigned int cycle_time)
{
	int setup_time, active_time, recovery_time, clock_time;
	u8 setup_count, active_count, recovery_count, recovery_count2, cycle_count;
	int bus_speed = system_bus_clock();

	if (pio_mode > 5)
		pio_mode = 5;
	setup_time  = ide_pio_timings[pio_mode].setup_time;
	active_time = ide_pio_timings[pio_mode].active_time;
	recovery_time = cycle_time - (setup_time + active_time);
	clock_time = 1000 / bus_speed;
	cycle_count = (cycle_time + clock_time - 1) / clock_time;

	setup_count = (setup_time + clock_time - 1) / clock_time;

	active_count = (active_time + clock_time - 1) / clock_time;
	if (active_count < 2)
		active_count = 2; /* minimum allowed by cmd640 */

	recovery_count = (recovery_time + clock_time - 1) / clock_time;
	recovery_count2 = cycle_count - (setup_count + active_count);
	if (recovery_count2 > recovery_count)
		recovery_count = recovery_count2;
	if (recovery_count < 2)
		recovery_count = 2; /* minimum allowed by cmd640 */
	if (recovery_count > 17) {
		active_count += recovery_count - 17;
		recovery_count = 17;
	}
	if (active_count > 16)
		active_count = 16; /* maximum allowed by cmd640 */
	if (cmd640_chip_version > 1)
		recovery_count -= 1;  /* cmd640b uses (count + 1)*/
	if (recovery_count > 16)
		recovery_count = 16; /* maximum allowed by cmd640 */

	setup_counts[index]    = setup_count;
	active_counts[index]   = active_count;
	recovery_counts[index] = recovery_count;

	/*
	 * In a perfect world, we might set the drive pio mode here
	 * (using WIN_SETFEATURE) before continuing.
	 *
	 * But we do not, because:
	 *	1) this is the wrong place to do it (proper is do_special() in ide.c)
	 * 	2) in practice this is rarely, if ever, necessary
	 */
	program_drive_counts (index);
}

static void cmd640_set_pio_mode(ide_drive_t *drive, const u8 pio)
{
	unsigned int index = 0, cycle_time;
	u8 b;

	while (drive != cmd_drives[index]) {
		if (++index > 3) {
			printk(KERN_ERR "%s: bad news in %s\n",
					drive->name, __FUNCTION__);
			return;
		}
	}
	switch (pio) {
		case 6: /* set fast-devsel off */
		case 7: /* set fast-devsel on */
			b = get_cmd640_reg(CNTRL) & ~0x27;
			if (pio & 1)
				b |= 0x27;
			put_cmd640_reg(CNTRL, b);
			printk("%s: %sabled cmd640 fast host timing (devsel)\n", drive->name, (pio & 1) ? "en" : "dis");
			return;

		case 8: /* set prefetch off */
		case 9: /* set prefetch on */
			set_prefetch_mode(index, pio & 1);
			printk("%s: %sabled cmd640 prefetch\n", drive->name, (pio & 1) ? "en" : "dis");
			return;
	}

	cycle_time = ide_pio_cycle_time(drive, pio);
	cmd640_set_mode(index, pio, cycle_time);

	printk("%s: selected cmd640 PIO mode%d (%dns)",
		drive->name, pio, cycle_time);

	display_clocks(index);
}

#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */

static int pci_conf1(void)
{
	unsigned long flags;
	u32 tmp;

	spin_lock_irqsave(&cmd640_lock, flags);
	outb(0x01, 0xCFB);
	tmp = inl(0xCF8);
	outl(0x80000000, 0xCF8);
	if (inl(0xCF8) == 0x80000000) {
		outl(tmp, 0xCF8);
		spin_unlock_irqrestore(&cmd640_lock, flags);
		return 1;
	}
	outl(tmp, 0xCF8);
	spin_unlock_irqrestore(&cmd640_lock, flags);
	return 0;
}

static int pci_conf2(void)
{
	unsigned long flags;

	spin_lock_irqsave(&cmd640_lock, flags);
	outb(0x00, 0xCFB);
	outb(0x00, 0xCF8);
	outb(0x00, 0xCFA);
	if (inb(0xCF8) == 0x00 && inb(0xCF8) == 0x00) {
		spin_unlock_irqrestore(&cmd640_lock, flags);
		return 1;
	}
	spin_unlock_irqrestore(&cmd640_lock, flags);
	return 0;
}

static const struct ide_port_info cmd640_port_info __initdata = {
	.chipset		= ide_cmd640,
	.host_flags		= IDE_HFLAG_SERIALIZE |
				  IDE_HFLAG_NO_DMA |
				  IDE_HFLAG_NO_AUTOTUNE |
				  IDE_HFLAG_ABUSE_PREFETCH |
				  IDE_HFLAG_ABUSE_FAST_DEVSEL,
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
	.pio_mask		= ATA_PIO5,
#endif
};

/*
 * Probe for a cmd640 chipset, and initialize it if found.
 */
static int __init cmd640x_init(void)
{
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
	int second_port_toggled = 0;
#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
	int second_port_cmd640 = 0;
	const char *bus_type, *port2;
	unsigned int index;
	u8 b, cfr;
	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };

	if (cmd640_vlb && probe_for_cmd640_vlb()) {
		bus_type = "VLB";
	} else {
		cmd640_vlb = 0;
		/* Find out what kind of PCI probing is supported otherwise
		   Justin Gibbs will sulk.. */
		if (pci_conf1() && probe_for_cmd640_pci1())
			bus_type = "PCI (type1)";
		else if (pci_conf2() && probe_for_cmd640_pci2())
			bus_type = "PCI (type2)";
		else
			return 0;
	}
	/*
	 * Undocumented magic (there is no 0x5b reg in specs)
	 */
	put_cmd640_reg(0x5b, 0xbd);
	if (get_cmd640_reg(0x5b) != 0xbd) {
		printk(KERN_ERR "ide: cmd640 init failed: wrong value in reg 0x5b\n");
		return 0;
	}
	put_cmd640_reg(0x5b, 0);

#ifdef CMD640_DUMP_REGS
	cmd640_dump_regs();
#endif

	/*
	 * Documented magic begins here
	 */
	cfr = get_cmd640_reg(CFR);
	cmd640_chip_version = cfr & CFR_DEVREV;
	if (cmd640_chip_version == 0) {
		printk ("ide: bad cmd640 revision: %d\n", cmd640_chip_version);
		return 0;
	}

	/*
	 * Initialize data for primary port
	 */
	setup_device_ptrs ();
	printk("%s: buggy cmd640%c interface on %s, config=0x%02x\n",
	       cmd_hwif0->name, 'a' + cmd640_chip_version - 1, bus_type, cfr);
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
	cmd_hwif0->set_pio_mode = &cmd640_set_pio_mode;
#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */

	idx[0] = cmd_hwif0->index;

	/*
	 * Ensure compatibility by always using the slowest timings
	 * for access to the drive's command register block,
	 * and reset the prefetch burstsize to default (512 bytes).
	 *
	 * Maybe we need a way to NOT do these on *some* systems?
	 */
	put_cmd640_reg(CMDTIM, 0);
	put_cmd640_reg(BRST, 0x40);

	/*
	 * Try to enable the secondary interface, if not already enabled
	 */
	if (cmd_hwif1->noprobe ||
	    (cmd_hwif1->drives[0].noprobe && cmd_hwif1->drives[1].noprobe)) {
		port2 = "not probed";
	} else {
		b = get_cmd640_reg(CNTRL);
		if (secondary_port_responding()) {
			if ((b & CNTRL_ENA_2ND)) {
				second_port_cmd640 = 1;
				port2 = "okay";
			} else if (cmd640_vlb) {
				second_port_cmd640 = 1;
				port2 = "alive";
			} else
				port2 = "not cmd640";
		} else {
			put_cmd640_reg(CNTRL, b ^ CNTRL_ENA_2ND); /* toggle the bit */
			if (secondary_port_responding()) {
				second_port_cmd640 = 1;
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
				second_port_toggled = 1;
#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
				port2 = "enabled";
			} else {
				put_cmd640_reg(CNTRL, b); /* restore original setting */
				port2 = "not responding";
			}
		}
	}

	/*
	 * Initialize data for secondary cmd640 port, if enabled
	 */
	if (second_port_cmd640) {
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
		cmd_hwif1->set_pio_mode = &cmd640_set_pio_mode;
#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */

		idx[1] = cmd_hwif1->index;
	}
	printk(KERN_INFO "%s: %sserialized, secondary interface %s\n", cmd_hwif1->name,
			 second_port_cmd640 ? "" : "not ", port2);

	/*
	 * Establish initial timings/prefetch for all drives.
	 * Do not unnecessarily disturb any prior BIOS setup of these.
	 */
	for (index = 0; index < (2 + (second_port_cmd640 << 1)); index++) {
		ide_drive_t *drive = cmd_drives[index];
#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
		if (drive->autotune || ((index > 1) && second_port_toggled)) {
	 		/*
	 		 * Reset timing to the slowest speed and turn off prefetch.
			 * This way, the drive identify code has a better chance.
			 */
			setup_counts    [index] = 4;	/* max possible */
			active_counts   [index] = 16;	/* max possible */
			recovery_counts [index] = 16;	/* max possible */
			program_drive_counts (index);
			set_prefetch_mode (index, 0);
			printk("cmd640: drive%d timings/prefetch cleared\n", index);
		} else {
			/*
			 * Record timings/prefetch without changing them.
			 * This preserves any prior BIOS setup.
			 */
			retrieve_drive_counts (index);
			check_prefetch (index);
			printk("cmd640: drive%d timings/prefetch(%s) preserved",
				index, drive->no_io_32bit ? "off" : "on");
			display_clocks(index);
		}
#else
		/*
		 * Set the drive unmask flags to match the prefetch setting
		 */
		check_prefetch (index);
		printk("cmd640: drive%d timings/prefetch(%s) preserved\n",
			index, drive->no_io_32bit ? "off" : "on");
#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
	}

#ifdef CMD640_DUMP_REGS
	cmd640_dump_regs();
#endif

	ide_device_add(idx, &cmd640_port_info);

	return 1;
}

module_param_named(probe_vlb, cmd640_vlb, bool, 0);
MODULE_PARM_DESC(probe_vlb, "probe for VLB version of CMD640 chipset");

module_init(cmd640x_init);

MODULE_LICENSE("GPL");