aboutsummaryrefslogtreecommitdiff
path: root/drivers/ata/libata-pmp.c
blob: d91f5090ba9d0d062e70d324b4e6566295e93d55 (plain)
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
/*
 * libata-pmp.c - libata port multiplier support
 *
 * Copyright (c) 2007  SUSE Linux Products GmbH
 * Copyright (c) 2007  Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 */

#include <linux/kernel.h>
#include <linux/libata.h>
#include "libata.h"

/**
 *	sata_pmp_read - read PMP register
 *	@link: link to read PMP register for
 *	@reg: register to read
 *	@r_val: resulting value
 *
 *	Read PMP register.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, AC_ERR_* mask on failure.
 */
static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pmp_dev = ap->link.device;
	struct ata_taskfile tf;
	unsigned int err_mask;

	ata_tf_init(pmp_dev, &tf);
	tf.command = ATA_CMD_PMP_READ;
	tf.protocol = ATA_PROT_NODATA;
	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
	tf.feature = reg;
	tf.device = link->pmp;

	err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
				     SATA_PMP_SCR_TIMEOUT);
	if (err_mask)
		return err_mask;

	*r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
	return 0;
}

/**
 *	sata_pmp_write - write PMP register
 *	@link: link to write PMP register for
 *	@reg: register to write
 *	@r_val: value to write
 *
 *	Write PMP register.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, AC_ERR_* mask on failure.
 */
static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pmp_dev = ap->link.device;
	struct ata_taskfile tf;

	ata_tf_init(pmp_dev, &tf);
	tf.command = ATA_CMD_PMP_WRITE;
	tf.protocol = ATA_PROT_NODATA;
	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
	tf.feature = reg;
	tf.device = link->pmp;
	tf.nsect = val & 0xff;
	tf.lbal = (val >> 8) & 0xff;
	tf.lbam = (val >> 16) & 0xff;
	tf.lbah = (val >> 24) & 0xff;

	return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
				 SATA_PMP_SCR_TIMEOUT);
}

/**
 *	sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
 *	@qc: ATA command in question
 *
 *	A host which has command switching PMP support cannot issue
 *	commands to multiple links simultaneously.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	ATA_DEFER_* if deferring is needed, 0 otherwise.
 */
int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
{
	struct ata_link *link = qc->dev->link;
	struct ata_port *ap = link->ap;

	if (ap->excl_link == NULL || ap->excl_link == link) {
		if (ap->nr_active_links == 0 || ata_link_active(link)) {
			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
			return ata_std_qc_defer(qc);
		}

		ap->excl_link = link;
	}

	return ATA_DEFER_PORT;
}

/**
 *	sata_pmp_scr_read - read PSCR
 *	@link: ATA link to read PSCR for
 *	@reg: PSCR to read
 *	@r_val: resulting value
 *
 *	Read PSCR @reg into @r_val for @link, to be called from
 *	ata_scr_read().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
{
	unsigned int err_mask;

	if (reg > SATA_PMP_PSCR_CONTROL)
		return -EINVAL;

	err_mask = sata_pmp_read(link, reg, r_val);
	if (err_mask) {
		ata_link_printk(link, KERN_WARNING, "failed to read SCR %d "
				"(Emask=0x%x)\n", reg, err_mask);
		return -EIO;
	}
	return 0;
}

/**
 *	sata_pmp_scr_write - write PSCR
 *	@link: ATA link to write PSCR for
 *	@reg: PSCR to write
 *	@val: value to be written
 *
 *	Write @val to PSCR @reg for @link, to be called from
 *	ata_scr_write() and ata_scr_write_flush().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
{
	unsigned int err_mask;

	if (reg > SATA_PMP_PSCR_CONTROL)
		return -EINVAL;

	err_mask = sata_pmp_write(link, reg, val);
	if (err_mask) {
		ata_link_printk(link, KERN_WARNING, "failed to write SCR %d "
				"(Emask=0x%x)\n", reg, err_mask);
		return -EIO;
	}
	return 0;
}

/**
 *	sata_pmp_std_prereset - prepare PMP link for reset
 *	@link: link to be reset
 *	@deadline: deadline jiffies for the operation
 *
 *	@link is about to be reset.  Initialize it.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline)
{
	struct ata_eh_context *ehc = &link->eh_context;
	const unsigned long *timing = sata_ehc_deb_timing(ehc);
	int rc;

	/* force HRST? */
	if (link->flags & ATA_LFLAG_NO_SRST)
		ehc->i.action |= ATA_EH_HARDRESET;

	/* handle link resume */
	if ((ehc->i.flags & ATA_EHI_RESUME_LINK) &&
	    (link->flags & ATA_LFLAG_HRST_TO_RESUME))
		ehc->i.action |= ATA_EH_HARDRESET;

	/* if we're about to do hardreset, nothing more to do */
	if (ehc->i.action & ATA_EH_HARDRESET)
		return 0;

	/* resume link */
	rc = sata_link_resume(link, timing, deadline);
	if (rc) {
		/* phy resume failed */
		ata_link_printk(link, KERN_WARNING, "failed to resume link "
				"for reset (errno=%d)\n", rc);
		return rc;
	}

	/* clear SError bits including .X which blocks the port when set */
	rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
	if (rc) {
		ata_link_printk(link, KERN_ERR,
				"failed to clear SError (errno=%d)\n", rc);
		return rc;
	}

	return 0;
}

/**
 *	sata_pmp_std_hardreset - standard hardreset method for PMP link
 *	@link: link to be reset
 *	@class: resulting class of attached device
 *	@deadline: deadline jiffies for the operation
 *
 *	Hardreset PMP port @link.  Note that this function doesn't
 *	wait for BSY clearance.  There simply isn't a generic way to
 *	wait the event.  Instead, this function return -EAGAIN thus
 *	telling libata-EH to followup with softreset.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class,
			   unsigned long deadline)
{
	const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
	u32 tmp;
	int rc;

	DPRINTK("ENTER\n");

	/* do hardreset */
	rc = sata_link_hardreset(link, timing, deadline);
	if (rc) {
		ata_link_printk(link, KERN_ERR,
				"COMRESET failed (errno=%d)\n", rc);
		goto out;
	}

	/* clear SError bits including .X which blocks the port when set */
	rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
	if (rc) {
		ata_link_printk(link, KERN_ERR, "failed to clear SError "
				"during hardreset (errno=%d)\n", rc);
		goto out;
	}

	/* if device is present, follow up with srst to wait for !BSY */
	if (ata_link_online(link))
		rc = -EAGAIN;
 out:
	/* if SCR isn't accessible, we need to reset the PMP */
	if (rc && rc != -EAGAIN && sata_scr_read(link, SCR_STATUS, &tmp))
		rc = -ERESTART;

	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	ata_std_postreset - standard postreset method for PMP link
 *	@link: the target ata_link
 *	@classes: classes of attached devices
 *
 *	This function is invoked after a successful reset.  Note that
 *	the device might have been reset more than once using
 *	different reset methods before postreset is invoked.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 */
void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class)
{
	u32 serror;

	DPRINTK("ENTER\n");

	/* clear SError */
	if (sata_scr_read(link, SCR_ERROR, &serror) == 0)
		sata_scr_write(link, SCR_ERROR, serror);

	/* print link status */
	sata_print_link_status(link);

	DPRINTK("EXIT\n");
}

/**
 *	sata_pmp_read_gscr - read GSCR block of SATA PMP
 *	@dev: PMP device
 *	@gscr: buffer to read GSCR block into
 *
 *	Read selected PMP GSCRs from the PMP at @dev.  This will serve
 *	as configuration and identification info for the PMP.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
{
	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
	int i;

	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
		int reg = gscr_to_read[i];
		unsigned int err_mask;

		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
		if (err_mask) {
			ata_dev_printk(dev, KERN_ERR, "failed to read PMP "
				"GSCR[%d] (Emask=0x%x)\n", reg, err_mask);
			return -EIO;
		}
	}

	return 0;
}

static const char *sata_pmp_spec_rev_str(const u32 *gscr)
{
	u32 rev = gscr[SATA_PMP_GSCR_REV];

	if (rev & (1 << 2))
		return "1.1";
	if (rev & (1 << 1))
		return "1.0";
	return "<unknown>";
}

static int sata_pmp_configure(struct ata_device *dev, int print_info)
{
	struct ata_port *ap = dev->link->ap;
	u32 *gscr = dev->gscr;
	unsigned int err_mask = 0;
	const char *reason;
	int nr_ports, rc;

	nr_ports = sata_pmp_gscr_ports(gscr);

	if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
		rc = -EINVAL;
		reason = "invalid nr_ports";
		goto fail;
	}

	if ((ap->flags & ATA_FLAG_AN) &&
	    (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
		dev->flags |= ATA_DFLAG_AN;

	/* monitor SERR_PHYRDY_CHG on fan-out ports */
	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
				  SERR_PHYRDY_CHG);
	if (err_mask) {
		rc = -EIO;
		reason = "failed to write GSCR_ERROR_EN";
		goto fail;
	}

	/* turn off notification till fan-out ports are reset and configured */
	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;

		err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_FEAT_EN,
					  gscr[SATA_PMP_GSCR_FEAT_EN]);
		if (err_mask) {
			rc = -EIO;
			reason = "failed to write GSCR_FEAT_EN";
			goto fail;
		}
	}

	if (print_info) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier %s, "
			       "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
			       sata_pmp_spec_rev_str(gscr),
			       sata_pmp_gscr_vendor(gscr),
			       sata_pmp_gscr_devid(gscr),
			       sata_pmp_gscr_rev(gscr),
			       nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
			       gscr[SATA_PMP_GSCR_FEAT]);

		if (!(dev->flags & ATA_DFLAG_AN))
			ata_dev_printk(dev, KERN_INFO,
				"Asynchronous notification not supported, "
				"hotplug won't\n         work on fan-out "
				"ports. Use warm-plug instead.\n");
	}

	return 0;

 fail:
	ata_dev_printk(dev, KERN_ERR,
		       "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
		       reason, err_mask);
	return rc;
}

static int sata_pmp_init_links(struct ata_port *ap, int nr_ports)
{
	struct ata_link *pmp_link = ap->pmp_link;
	int i;

	if (!pmp_link) {
		pmp_link = kzalloc(sizeof(pmp_link[0]) * SATA_PMP_MAX_PORTS,
				   GFP_NOIO);
		if (!pmp_link)
			return -ENOMEM;

		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
			ata_link_init(ap, &pmp_link[i], i);

		ap->pmp_link = pmp_link;
	}

	for (i = 0; i < nr_ports; i++) {
		struct ata_link *link = &pmp_link[i];
		struct ata_eh_context *ehc = &link->eh_context;

		link->flags = 0;
		ehc->i.probe_mask |= 1;
		ehc->i.action |= ATA_EH_SOFTRESET;
		ehc->i.flags |= ATA_EHI_RESUME_LINK;
	}

	return 0;
}

static void sata_pmp_quirks(struct ata_port *ap)
{
	u32 *gscr = ap->link.device->gscr;
	u16 vendor = sata_pmp_gscr_vendor(gscr);
	u16 devid = sata_pmp_gscr_devid(gscr);
	struct ata_link *link;

	if (vendor == 0x1095 && devid == 0x3726) {
		/* sil3726 quirks */
		ata_port_for_each_link(link, ap) {
			/* SError.N need a kick in the ass to get working */
			link->flags |= ATA_LFLAG_HRST_TO_RESUME;

			/* class code report is unreliable */
			if (link->pmp < 5)
				link->flags |= ATA_LFLAG_ASSUME_ATA;

			/* port 5 is for SEMB device and it doesn't like SRST */
			if (link->pmp == 5)
				link->flags |= ATA_LFLAG_NO_SRST |
					       ATA_LFLAG_ASSUME_SEMB;
		}
	} else if (vendor == 0x1095 && devid == 0x4723) {
		/* sil4723 quirks */
		ata_port_for_each_link(link, ap) {
			/* SError.N need a kick in the ass to get working */
			link->flags |= ATA_LFLAG_HRST_TO_RESUME;

			/* class code report is unreliable */
			if (link->pmp < 2)
				link->flags |= ATA_LFLAG_ASSUME_ATA;

			/* the config device at port 2 locks up on SRST */
			if (link->pmp == 2)
				link->flags |= ATA_LFLAG_NO_SRST |
					       ATA_LFLAG_ASSUME_ATA;
		}
	} else if (vendor == 0x1095 && devid == 0x4726) {
		/* sil4726 quirks */
		ata_port_for_each_link(link, ap) {
			/* SError.N need a kick in the ass to get working */
			link->flags |= ATA_LFLAG_HRST_TO_RESUME;

			/* Class code report is unreliable and SRST
			 * times out under certain configurations.
			 * Config device can be at port 0 or 5 and
			 * locks up on SRST.
			 */
			if (link->pmp <= 5)
				link->flags |= ATA_LFLAG_NO_SRST |
					       ATA_LFLAG_ASSUME_ATA;

			/* Port 6 is for SEMB device which doesn't
			 * like SRST either.
			 */
			if (link->pmp == 6)
				link->flags |= ATA_LFLAG_NO_SRST |
					       ATA_LFLAG_ASSUME_SEMB;
		}
	} else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
					devid == 0x5734 || devid == 0x5744)) {
		/* sil5723/5744 quirks */

		/* sil5723/5744 has either two or three downstream
		 * ports depending on operation mode.  The last port
		 * is empty if any actual IO device is available or
		 * occupied by a pseudo configuration device
		 * otherwise.  Don't try hard to recover it.
		 */
		ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;
	} else if (vendor == 0x11ab && devid == 0x4140) {
		/* Marvell 88SM4140 quirks.  Fan-out ports require PHY
		 * reset to work; other than that, it behaves very
		 * nicely.
		 */
		ata_port_for_each_link(link, ap)
			link->flags |= ATA_LFLAG_HRST_TO_RESUME;
	}
}

/**
 *	sata_pmp_attach - attach a SATA PMP device
 *	@dev: SATA PMP device to attach
 *
 *	Configure and attach SATA PMP device @dev.  This function is
 *	also responsible for allocating and initializing PMP links.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int sata_pmp_attach(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	unsigned long flags;
	struct ata_link *tlink;
	int rc;

	/* is it hanging off the right place? */
	if (!(ap->flags & ATA_FLAG_PMP)) {
		ata_dev_printk(dev, KERN_ERR,
			       "host does not support Port Multiplier\n");
		return -EINVAL;
	}

	if (!ata_is_host_link(link)) {
		ata_dev_printk(dev, KERN_ERR,
			       "Port Multipliers cannot be nested\n");
		return -EINVAL;
	}

	if (dev->devno) {
		ata_dev_printk(dev, KERN_ERR,
			       "Port Multiplier must be the first device\n");
		return -EINVAL;
	}

	WARN_ON(link->pmp != 0);
	link->pmp = SATA_PMP_CTRL_PORT;

	/* read GSCR block */
	rc = sata_pmp_read_gscr(dev, dev->gscr);
	if (rc)
		goto fail;

	/* config PMP */
	rc = sata_pmp_configure(dev, 1);
	if (rc)
		goto fail;

	rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
	if (rc) {
		ata_dev_printk(dev, KERN_INFO,
			       "failed to initialize PMP links\n");
		goto fail;
	}

	/* attach it */
	spin_lock_irqsave(ap->lock, flags);
	WARN_ON(ap->nr_pmp_links);
	ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
	spin_unlock_irqrestore(ap->lock, flags);

	sata_pmp_quirks(ap);

	if (ap->ops->pmp_attach)
		ap->ops->pmp_attach(ap);

	ata_port_for_each_link(tlink, ap)
		sata_link_init_spd(tlink);

	ata_acpi_associate_sata_port(ap);

	return 0;

 fail:
	link->pmp = 0;
	return rc;
}

/**
 *	sata_pmp_detach - detach a SATA PMP device
 *	@dev: SATA PMP device to detach
 *
 *	Detach SATA PMP device @dev.  This function is also
 *	responsible for deconfiguring PMP links.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
static void sata_pmp_detach(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ata_link *tlink;
	unsigned long flags;

	ata_dev_printk(dev, KERN_INFO, "Port Multiplier detaching\n");

	WARN_ON(!ata_is_host_link(link) || dev->devno ||
		link->pmp != SATA_PMP_CTRL_PORT);

	if (ap->ops->pmp_detach)
		ap->ops->pmp_detach(ap);

	ata_port_for_each_link(tlink, ap)
		ata_eh_detach_dev(tlink->device);

	spin_lock_irqsave(ap->lock, flags);
	ap->nr_pmp_links = 0;
	link->pmp = 0;
	spin_unlock_irqrestore(ap->lock, flags);

	ata_acpi_associate_sata_port(ap);
}

/**
 *	sata_pmp_same_pmp - does new GSCR matches the configured PMP?
 *	@dev: PMP device to compare against
 *	@new_gscr: GSCR block of the new device
 *
 *	Compare @new_gscr against @dev and determine whether @dev is
 *	the PMP described by @new_gscr.
 *
 *	LOCKING:
 *	None.
 *
 *	RETURNS:
 *	1 if @dev matches @new_gscr, 0 otherwise.
 */
static int sata_pmp_same_pmp(struct ata_device *dev, const u32 *new_gscr)
{
	const u32 *old_gscr = dev->gscr;
	u16 old_vendor, new_vendor, old_devid, new_devid;
	int old_nr_ports, new_nr_ports;

	old_vendor = sata_pmp_gscr_vendor(old_gscr);
	new_vendor = sata_pmp_gscr_vendor(new_gscr);
	old_devid = sata_pmp_gscr_devid(old_gscr);
	new_devid = sata_pmp_gscr_devid(new_gscr);
	old_nr_ports = sata_pmp_gscr_ports(old_gscr);
	new_nr_ports = sata_pmp_gscr_ports(new_gscr);

	if (old_vendor != new_vendor) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "vendor mismatch '0x%x' != '0x%x'\n",
			       old_vendor, new_vendor);
		return 0;
	}

	if (old_devid != new_devid) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "device ID mismatch '0x%x' != '0x%x'\n",
			       old_devid, new_devid);
		return 0;
	}

	if (old_nr_ports != new_nr_ports) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "nr_ports mismatch '0x%x' != '0x%x'\n",
			       old_nr_ports, new_nr_ports);
		return 0;
	}

	return 1;
}

/**
 *	sata_pmp_revalidate - revalidate SATA PMP
 *	@dev: PMP device to revalidate
 *	@new_class: new class code
 *
 *	Re-read GSCR block and make sure @dev is still attached to the
 *	port and properly configured.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
static int sata_pmp_revalidate(struct ata_device *dev, unsigned int new_class)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	u32 *gscr = (void *)ap->sector_buf;
	int rc;

	DPRINTK("ENTER\n");

	ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);

	if (!ata_dev_enabled(dev)) {
		rc = -ENODEV;
		goto fail;
	}

	/* wrong class? */
	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
		rc = -ENODEV;
		goto fail;
	}

	/* read GSCR */
	rc = sata_pmp_read_gscr(dev, gscr);
	if (rc)
		goto fail;

	/* is the pmp still there? */
	if (!sata_pmp_same_pmp(dev, gscr)) {
		rc = -ENODEV;
		goto fail;
	}

	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);

	rc = sata_pmp_configure(dev, 0);
	if (rc)
		goto fail;

	ata_eh_done(link, NULL, ATA_EH_REVALIDATE);

	DPRINTK("EXIT, rc=0\n");
	return 0;

 fail:
	ata_dev_printk(dev, KERN_ERR,
		       "PMP revalidation failed (errno=%d)\n", rc);
	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	sata_pmp_revalidate_quick - revalidate SATA PMP quickly
 *	@dev: PMP device to revalidate
 *
 *	Make sure the attached PMP is accessible.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
static int sata_pmp_revalidate_quick(struct ata_device *dev)
{
	unsigned int err_mask;
	u32 prod_id;

	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
	if (err_mask) {
		ata_dev_printk(dev, KERN_ERR, "failed to read PMP product ID "
			       "(Emask=0x%x)\n", err_mask);
		return -EIO;
	}

	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
		ata_dev_printk(dev, KERN_ERR, "PMP product ID mismatch\n");
		/* something weird is going on, request full PMP recovery */
		return -EIO;
	}

	return 0;
}

/**
 *	sata_pmp_eh_recover_pmp - recover PMP
 *	@ap: ATA port PMP is attached to
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *
 *	Recover PMP attached to @ap.  Recovery procedure is somewhat
 *	similar to that of ata_eh_recover() except that reset should
 *	always be performed in hard->soft sequence and recovery
 *	failure results in PMP detachment.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
{
	struct ata_link *link = &ap->link;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev = link->device;
	int tries = ATA_EH_PMP_TRIES;
	int detach = 0, rc = 0;
	int reval_failed = 0;

	DPRINTK("ENTER\n");

	if (dev->flags & ATA_DFLAG_DETACH) {
		detach = 1;
		goto fail;
	}

 retry:
	ehc->classes[0] = ATA_DEV_UNKNOWN;

	if (ehc->i.action & ATA_EH_RESET_MASK) {
		struct ata_link *tlink;

		ata_eh_freeze_port(ap);

		/* reset */
		ehc->i.action = ATA_EH_HARDRESET;
		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
				  postreset);
		if (rc) {
			ata_link_printk(link, KERN_ERR,
					"failed to reset PMP, giving up\n");
			goto fail;
		}

		ata_eh_thaw_port(ap);

		/* PMP is reset, SErrors cannot be trusted, scan all */
		ata_port_for_each_link(tlink, ap)
			ata_ehi_schedule_probe(&tlink->eh_context.i);
	}

	/* If revalidation is requested, revalidate and reconfigure;
	 * otherwise, do quick revalidation.
	 */
	if (ehc->i.action & ATA_EH_REVALIDATE)
		rc = sata_pmp_revalidate(dev, ehc->classes[0]);
	else
		rc = sata_pmp_revalidate_quick(dev);

	if (rc) {
		tries--;

		if (rc == -ENODEV) {
			ehc->i.probe_mask |= 1;
			detach = 1;
			/* give it just two more chances */
			tries = min(tries, 2);
		}

		if (tries) {
			int sleep = ehc->i.flags & ATA_EHI_DID_RESET;

			/* consecutive revalidation failures? speed down */
			if (reval_failed)
				sata_down_spd_limit(link);
			else
				reval_failed = 1;

			ata_dev_printk(dev, KERN_WARNING,
				       "retrying hardreset%s\n",
				       sleep ? " in 5 secs" : "");
			if (sleep)
				ssleep(5);
			ehc->i.action |= ATA_EH_HARDRESET;
			goto retry;
		} else {
			ata_dev_printk(dev, KERN_ERR, "failed to recover PMP "
				       "after %d tries, giving up\n",
				       ATA_EH_PMP_TRIES);
			goto fail;
		}
	}

	/* okay, PMP resurrected */
	ehc->i.flags = 0;

	DPRINTK("EXIT, rc=0\n");
	return 0;

 fail:
	sata_pmp_detach(dev);
	if (detach)
		ata_eh_detach_dev(dev);
	else
		ata_dev_disable(dev);

	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
{
	struct ata_link *link;
	unsigned long flags;
	int rc;

	spin_lock_irqsave(ap->lock, flags);

	ata_port_for_each_link(link, ap) {
		if (!(link->flags & ATA_LFLAG_DISABLED))
			continue;

		spin_unlock_irqrestore(ap->lock, flags);

		/* Some PMPs require hardreset sequence to get
		 * SError.N working.
		 */
		if ((link->flags & ATA_LFLAG_HRST_TO_RESUME) &&
		    (link->eh_context.i.flags & ATA_EHI_RESUME_LINK))
			sata_link_hardreset(link, sata_deb_timing_normal,
					    jiffies + ATA_TMOUT_INTERNAL_QUICK);

		/* unconditionally clear SError.N */
		rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
		if (rc) {
			ata_link_printk(link, KERN_ERR, "failed to clear "
					"SError.N (errno=%d)\n", rc);
			return rc;
		}

		spin_lock_irqsave(ap->lock, flags);
	}

	spin_unlock_irqrestore(ap->lock, flags);

	return 0;
}

static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
{
	struct ata_port *ap = link->ap;
	unsigned long flags;

	if (link_tries[link->pmp] && --link_tries[link->pmp])
		return 1;

	/* disable this link */
	if (!(link->flags & ATA_LFLAG_DISABLED)) {
		ata_link_printk(link, KERN_WARNING,
			"failed to recover link after %d tries, disabling\n",
			ATA_EH_PMP_LINK_TRIES);

		spin_lock_irqsave(ap->lock, flags);
		link->flags |= ATA_LFLAG_DISABLED;
		spin_unlock_irqrestore(ap->lock, flags);
	}

	ata_dev_disable(link->device);
	link->eh_context.i.action = 0;

	return 0;
}

/**
 *	sata_pmp_eh_recover - recover PMP-enabled port
 *	@ap: ATA port to recover
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *	@pmp_prereset: PMP prereset method (can be NULL)
 *	@pmp_softreset: PMP softreset method (can be NULL)
 *	@pmp_hardreset: PMP hardreset method (can be NULL)
 *	@pmp_postreset: PMP postreset method (can be NULL)
 *
 *	Drive EH recovery operation for PMP enabled port @ap.  This
 *	function recovers host and PMP ports with proper retrials and
 *	fallbacks.  Actual recovery operations are performed using
 *	ata_eh_recover() and sata_pmp_eh_recover_pmp().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sata_pmp_eh_recover(struct ata_port *ap,
		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
		ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
		ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
{
	int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
	struct ata_link *pmp_link = &ap->link;
	struct ata_device *pmp_dev = pmp_link->device;
	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
	struct ata_link *link;
	struct ata_device *dev;
	unsigned int err_mask;
	u32 gscr_error, sntf;
	int cnt, rc;

	pmp_tries = ATA_EH_PMP_TRIES;
	ata_port_for_each_link(link, ap)
		link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;

 retry:
	/* PMP attached? */
	if (!ap->nr_pmp_links) {
		rc = ata_eh_recover(ap, prereset, softreset, hardreset,
				    postreset, NULL);
		if (rc) {
			ata_link_for_each_dev(dev, &ap->link)
				ata_dev_disable(dev);
			return rc;
		}

		if (pmp_dev->class != ATA_DEV_PMP)
			return 0;

		/* new PMP online */
		ata_port_for_each_link(link, ap)
			link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;

		/* fall through */
	}

	/* recover pmp */
	rc = sata_pmp_eh_recover_pmp(ap, prereset, softreset, hardreset,
				     postreset);
	if (rc)
		goto pmp_fail;

	/* handle disabled links */
	rc = sata_pmp_eh_handle_disabled_links(ap);
	if (rc)
		goto pmp_fail;

	/* recover links */
	rc = ata_eh_recover(ap, pmp_prereset, pmp_softreset, pmp_hardreset,
			    pmp_postreset, &link);
	if (rc)
		goto link_fail;

	/* Connection status might have changed while resetting other
	 * links, check SATA_PMP_GSCR_ERROR before returning.
	 */

	/* clear SNotification */
	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
	if (rc == 0)
		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);

	/* enable notification */
	if (pmp_dev->flags & ATA_DFLAG_AN) {
		pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;

		err_mask = sata_pmp_write(pmp_dev->link, SATA_PMP_GSCR_FEAT_EN,
					  pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN]);
		if (err_mask) {
			ata_dev_printk(pmp_dev, KERN_ERR, "failed to write "
				       "PMP_FEAT_EN (Emask=0x%x)\n", err_mask);
			rc = -EIO;
			goto pmp_fail;
		}
	}

	/* check GSCR_ERROR */
	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
	if (err_mask) {
		ata_dev_printk(pmp_dev, KERN_ERR, "failed to read "
			       "PMP_GSCR_ERROR (Emask=0x%x)\n", err_mask);
		rc = -EIO;
		goto pmp_fail;
	}

	cnt = 0;
	ata_port_for_each_link(link, ap) {
		if (!(gscr_error & (1 << link->pmp)))
			continue;

		if (sata_pmp_handle_link_fail(link, link_tries)) {
			ata_ehi_hotplugged(&link->eh_context.i);
			cnt++;
		} else {
			ata_link_printk(link, KERN_WARNING,
				"PHY status changed but maxed out on retries, "
				"giving up\n");
			ata_link_printk(link, KERN_WARNING,
				"Manully issue scan to resume this link\n");
		}
	}

	if (cnt) {
		ata_port_printk(ap, KERN_INFO, "PMP SError.N set for some "
				"ports, repeating recovery\n");
		goto retry;
	}

	return 0;

 link_fail:
	if (sata_pmp_handle_link_fail(link, link_tries)) {
		pmp_ehc->i.action |= ATA_EH_HARDRESET;
		goto retry;
	}

	/* fall through */
 pmp_fail:
	/* Control always ends up here after detaching PMP.  Shut up
	 * and return if we're unloading.
	 */
	if (ap->pflags & ATA_PFLAG_UNLOADING)
		return rc;

	if (!ap->nr_pmp_links)
		goto retry;

	if (--pmp_tries) {
		ata_port_printk(ap, KERN_WARNING,
				"failed to recover PMP, retrying in 5 secs\n");
		pmp_ehc->i.action |= ATA_EH_HARDRESET;
		ssleep(5);
		goto retry;
	}

	ata_port_printk(ap, KERN_ERR,
			"failed to recover PMP after %d tries, giving up\n",
			ATA_EH_PMP_TRIES);
	sata_pmp_detach(pmp_dev);
	ata_dev_disable(pmp_dev);

	return rc;
}

/**
 *	sata_pmp_do_eh - do standard error handling for PMP-enabled host
 *	@ap: host port to handle error for
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *	@pmp_prereset: PMP prereset method (can be NULL)
 *	@pmp_softreset: PMP softreset method (can be NULL)
 *	@pmp_hardreset: PMP hardreset method (can be NULL)
 *	@pmp_postreset: PMP postreset method (can be NULL)
 *
 *	Perform standard error handling sequence for PMP-enabled host
 *	@ap.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void sata_pmp_do_eh(struct ata_port *ap,
		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
		ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
		ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
{
	ata_eh_autopsy(ap);
	ata_eh_report(ap);
	sata_pmp_eh_recover(ap, prereset, softreset, hardreset, postreset,
			    pmp_prereset, pmp_softreset, pmp_hardreset,
			    pmp_postreset);
	ata_eh_finish(ap);
}