summaryrefslogtreecommitdiffstats
path: root/drivers/usb/host/xhci-dbgcap.c
blob: d82935d31126dd020d941b7a7cd8c78a93f3392f (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
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
// SPDX-License-Identifier: GPL-2.0
/*
 * xhci-dbgcap.c - xHCI debug capability support
 *
 * Copyright (C) 2017 Intel Corporation
 *
 * Author: Lu Baolu <baolu.lu@linux.intel.com>
 */
#include <linux/bug.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/kstrtox.h>
#include <linux/list.h>
#include <linux/nls.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include <linux/io-64-nonatomic-lo-hi.h>

#include <asm/byteorder.h>

#include "xhci.h"
#include "xhci-trace.h"
#include "xhci-dbgcap.h"

static void dbc_free_ctx(struct device *dev, struct xhci_container_ctx *ctx)
{
	if (!ctx)
		return;
	dma_free_coherent(dev, ctx->size, ctx->bytes, ctx->dma);
	kfree(ctx);
}

/* we use only one segment for DbC rings */
static void dbc_ring_free(struct device *dev, struct xhci_ring *ring)
{
	if (!ring)
		return;

	if (ring->first_seg) {
		dma_free_coherent(dev, TRB_SEGMENT_SIZE,
				  ring->first_seg->trbs,
				  ring->first_seg->dma);
		kfree(ring->first_seg);
	}
	kfree(ring);
}

static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
{
	struct usb_string_descriptor	*s_desc;
	u32				string_length;

	/* Serial string: */
	s_desc = (struct usb_string_descriptor *)strings->serial;
	utf8s_to_utf16s(DBC_STRING_SERIAL, strlen(DBC_STRING_SERIAL),
			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
			DBC_MAX_STRING_LENGTH);

	s_desc->bLength		= (strlen(DBC_STRING_SERIAL) + 1) * 2;
	s_desc->bDescriptorType	= USB_DT_STRING;
	string_length		= s_desc->bLength;
	string_length		<<= 8;

	/* Product string: */
	s_desc = (struct usb_string_descriptor *)strings->product;
	utf8s_to_utf16s(DBC_STRING_PRODUCT, strlen(DBC_STRING_PRODUCT),
			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
			DBC_MAX_STRING_LENGTH);

	s_desc->bLength		= (strlen(DBC_STRING_PRODUCT) + 1) * 2;
	s_desc->bDescriptorType	= USB_DT_STRING;
	string_length		+= s_desc->bLength;
	string_length		<<= 8;

	/* Manufacture string: */
	s_desc = (struct usb_string_descriptor *)strings->manufacturer;
	utf8s_to_utf16s(DBC_STRING_MANUFACTURER,
			strlen(DBC_STRING_MANUFACTURER),
			UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
			DBC_MAX_STRING_LENGTH);

	s_desc->bLength		= (strlen(DBC_STRING_MANUFACTURER) + 1) * 2;
	s_desc->bDescriptorType	= USB_DT_STRING;
	string_length		+= s_desc->bLength;
	string_length		<<= 8;

	/* String0: */
	strings->string0[0]	= 4;
	strings->string0[1]	= USB_DT_STRING;
	strings->string0[2]	= 0x09;
	strings->string0[3]	= 0x04;
	string_length		+= 4;

	return string_length;
}

static void xhci_dbc_init_contexts(struct xhci_dbc *dbc, u32 string_length)
{
	struct dbc_info_context	*info;
	struct xhci_ep_ctx	*ep_ctx;
	u32			dev_info;
	dma_addr_t		deq, dma;
	unsigned int		max_burst;

	if (!dbc)
		return;

	/* Populate info Context: */
	info			= (struct dbc_info_context *)dbc->ctx->bytes;
	dma			= dbc->string_dma;
	info->string0		= cpu_to_le64(dma);
	info->manufacturer	= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH);
	info->product		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 2);
	info->serial		= cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 3);
	info->length		= cpu_to_le32(string_length);

	/* Populate bulk out endpoint context: */
	ep_ctx			= dbc_bulkout_ctx(dbc);
	max_burst		= DBC_CTRL_MAXBURST(readl(&dbc->regs->control));
	deq			= dbc_bulkout_enq(dbc);
	ep_ctx->ep_info		= 0;
	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_OUT_EP, 1024, max_burst);
	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_out->cycle_state);

	/* Populate bulk in endpoint context: */
	ep_ctx			= dbc_bulkin_ctx(dbc);
	deq			= dbc_bulkin_enq(dbc);
	ep_ctx->ep_info		= 0;
	ep_ctx->ep_info2	= dbc_epctx_info2(BULK_IN_EP, 1024, max_burst);
	ep_ctx->deq		= cpu_to_le64(deq | dbc->ring_in->cycle_state);

	/* Set DbC context and info registers: */
	lo_hi_writeq(dbc->ctx->dma, &dbc->regs->dccp);

	dev_info = (dbc->idVendor << 16) | dbc->bInterfaceProtocol;
	writel(dev_info, &dbc->regs->devinfo1);

	dev_info = (dbc->bcdDevice << 16) | dbc->idProduct;
	writel(dev_info, &dbc->regs->devinfo2);
}

static void xhci_dbc_giveback(struct dbc_request *req, int status)
	__releases(&dbc->lock)
	__acquires(&dbc->lock)
{
	struct xhci_dbc		*dbc = req->dbc;
	struct device		*dev = dbc->dev;

	list_del_init(&req->list_pending);
	req->trb_dma = 0;
	req->trb = NULL;

	if (req->status == -EINPROGRESS)
		req->status = status;

	trace_xhci_dbc_giveback_request(req);

	dma_unmap_single(dev,
			 req->dma,
			 req->length,
			 dbc_ep_dma_direction(req));

	/* Give back the transfer request: */
	spin_unlock(&dbc->lock);
	req->complete(dbc, req);
	spin_lock(&dbc->lock);
}

static void xhci_dbc_flush_single_request(struct dbc_request *req)
{
	union xhci_trb	*trb = req->trb;

	trb->generic.field[0]	= 0;
	trb->generic.field[1]	= 0;
	trb->generic.field[2]	= 0;
	trb->generic.field[3]	&= cpu_to_le32(TRB_CYCLE);
	trb->generic.field[3]	|= cpu_to_le32(TRB_TYPE(TRB_TR_NOOP));

	xhci_dbc_giveback(req, -ESHUTDOWN);
}

static void xhci_dbc_flush_endpoint_requests(struct dbc_ep *dep)
{
	struct dbc_request	*req, *tmp;

	list_for_each_entry_safe(req, tmp, &dep->list_pending, list_pending)
		xhci_dbc_flush_single_request(req);
}

static void xhci_dbc_flush_requests(struct xhci_dbc *dbc)
{
	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]);
	xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]);
}

struct dbc_request *
dbc_alloc_request(struct xhci_dbc *dbc, unsigned int direction, gfp_t flags)
{
	struct dbc_request	*req;

	if (direction != BULK_IN &&
	    direction != BULK_OUT)
		return NULL;

	if (!dbc)
		return NULL;

	req = kzalloc(sizeof(*req), flags);
	if (!req)
		return NULL;

	req->dbc = dbc;
	INIT_LIST_HEAD(&req->list_pending);
	INIT_LIST_HEAD(&req->list_pool);
	req->direction = direction;

	trace_xhci_dbc_alloc_request(req);

	return req;
}

void
dbc_free_request(struct dbc_request *req)
{
	trace_xhci_dbc_free_request(req);

	kfree(req);
}

static void
xhci_dbc_queue_trb(struct xhci_ring *ring, u32 field1,
		   u32 field2, u32 field3, u32 field4)
{
	union xhci_trb		*trb, *next;

	trb = ring->enqueue;
	trb->generic.field[0]	= cpu_to_le32(field1);
	trb->generic.field[1]	= cpu_to_le32(field2);
	trb->generic.field[2]	= cpu_to_le32(field3);
	trb->generic.field[3]	= cpu_to_le32(field4);

	trace_xhci_dbc_gadget_ep_queue(ring, &trb->generic);

	ring->num_trbs_free--;
	next = ++(ring->enqueue);
	if (TRB_TYPE_LINK_LE32(next->link.control)) {
		next->link.control ^= cpu_to_le32(TRB_CYCLE);
		ring->enqueue = ring->enq_seg->trbs;
		ring->cycle_state ^= 1;
	}
}

static int xhci_dbc_queue_bulk_tx(struct dbc_ep *dep,
				  struct dbc_request *req)
{
	u64			addr;
	union xhci_trb		*trb;
	unsigned int		num_trbs;
	struct xhci_dbc		*dbc = req->dbc;
	struct xhci_ring	*ring = dep->ring;
	u32			length, control, cycle;

	num_trbs = count_trbs(req->dma, req->length);
	WARN_ON(num_trbs != 1);
	if (ring->num_trbs_free < num_trbs)
		return -EBUSY;

	addr	= req->dma;
	trb	= ring->enqueue;
	cycle	= ring->cycle_state;
	length	= TRB_LEN(req->length);
	control	= TRB_TYPE(TRB_NORMAL) | TRB_IOC;

	if (cycle)
		control &= cpu_to_le32(~TRB_CYCLE);
	else
		control |= cpu_to_le32(TRB_CYCLE);

	req->trb = ring->enqueue;
	req->trb_dma = xhci_trb_virt_to_dma(ring->enq_seg, ring->enqueue);
	xhci_dbc_queue_trb(ring,
			   lower_32_bits(addr),
			   upper_32_bits(addr),
			   length, control);

	/*
	 * Add a barrier between writes of trb fields and flipping
	 * the cycle bit:
	 */
	wmb();

	if (cycle)
		trb->generic.field[3] |= cpu_to_le32(TRB_CYCLE);
	else
		trb->generic.field[3] &= cpu_to_le32(~TRB_CYCLE);

	writel(DBC_DOOR_BELL_TARGET(dep->direction), &dbc->regs->doorbell);

	return 0;
}

static int
dbc_ep_do_queue(struct dbc_request *req)
{
	int			ret;
	struct xhci_dbc		*dbc = req->dbc;
	struct device		*dev = dbc->dev;
	struct dbc_ep		*dep = &dbc->eps[req->direction];

	if (!req->length || !req->buf)
		return -EINVAL;

	req->actual		= 0;
	req->status		= -EINPROGRESS;

	req->dma = dma_map_single(dev,
				  req->buf,
				  req->length,
				  dbc_ep_dma_direction(dep));
	if (dma_mapping_error(dev, req->dma)) {
		dev_err(dbc->dev, "failed to map buffer\n");
		return -EFAULT;
	}

	ret = xhci_dbc_queue_bulk_tx(dep, req);
	if (ret) {
		dev_err(dbc->dev, "failed to queue trbs\n");
		dma_unmap_single(dev,
				 req->dma,
				 req->length,
				 dbc_ep_dma_direction(dep));
		return -EFAULT;
	}

	list_add_tail(&req->list_pending, &dep->list_pending);

	return 0;
}

int dbc_ep_queue(struct dbc_request *req)
{
	unsigned long		flags;
	struct xhci_dbc		*dbc = req->dbc;
	int			ret = -ESHUTDOWN;

	if (!dbc)
		return -ENODEV;

	if (req->direction != BULK_IN &&
	    req->direction != BULK_OUT)
		return -EINVAL;

	spin_lock_irqsave(&dbc->lock, flags);
	if (dbc->state == DS_CONFIGURED)
		ret = dbc_ep_do_queue(req);
	spin_unlock_irqrestore(&dbc->lock, flags);

	mod_delayed_work(system_wq, &dbc->event_work, 0);

	trace_xhci_dbc_queue_request(req);

	return ret;
}

static inline void xhci_dbc_do_eps_init(struct xhci_dbc *dbc, bool direction)
{
	struct dbc_ep		*dep;

	dep			= &dbc->eps[direction];
	dep->dbc		= dbc;
	dep->direction		= direction;
	dep->ring		= direction ? dbc->ring_in : dbc->ring_out;

	INIT_LIST_HEAD(&dep->list_pending);
}

static void xhci_dbc_eps_init(struct xhci_dbc *dbc)
{
	xhci_dbc_do_eps_init(dbc, BULK_OUT);
	xhci_dbc_do_eps_init(dbc, BULK_IN);
}

static void xhci_dbc_eps_exit(struct xhci_dbc *dbc)
{
	memset(dbc->eps, 0, sizeof_field(struct xhci_dbc, eps));
}

static int dbc_erst_alloc(struct device *dev, struct xhci_ring *evt_ring,
		    struct xhci_erst *erst, gfp_t flags)
{
	erst->entries = dma_alloc_coherent(dev, sizeof(*erst->entries),
					   &erst->erst_dma_addr, flags);
	if (!erst->entries)
		return -ENOMEM;

	erst->num_entries = 1;
	erst->entries[0].seg_addr = cpu_to_le64(evt_ring->first_seg->dma);
	erst->entries[0].seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
	erst->entries[0].rsvd = 0;
	return 0;
}

static void dbc_erst_free(struct device *dev, struct xhci_erst *erst)
{
	dma_free_coherent(dev, sizeof(*erst->entries), erst->entries,
			  erst->erst_dma_addr);
	erst->entries = NULL;
}

static struct xhci_container_ctx *
dbc_alloc_ctx(struct device *dev, gfp_t flags)
{
	struct xhci_container_ctx *ctx;

	ctx = kzalloc(sizeof(*ctx), flags);
	if (!ctx)
		return NULL;

	/* xhci 7.6.9, all three contexts; info, ep-out and ep-in. Each 64 bytes*/
	ctx->size = 3 * DBC_CONTEXT_SIZE;
	ctx->bytes = dma_alloc_coherent(dev, ctx->size, &ctx->dma, flags);
	if (!ctx->bytes) {
		kfree(ctx);
		return NULL;
	}
	return ctx;
}

static struct xhci_ring *
xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
{
	struct xhci_ring *ring;
	struct xhci_segment *seg;
	dma_addr_t dma;

	ring = kzalloc(sizeof(*ring), flags);
	if (!ring)
		return NULL;

	ring->num_segs = 1;
	ring->type = type;

	seg = kzalloc(sizeof(*seg), flags);
	if (!seg)
		goto seg_fail;

	ring->first_seg = seg;
	ring->last_seg = seg;
	seg->next = seg;

	seg->trbs = dma_alloc_coherent(dev, TRB_SEGMENT_SIZE, &dma, flags);
	if (!seg->trbs)
		goto dma_fail;

	seg->dma = dma;

	/* Only event ring does not use link TRB */
	if (type != TYPE_EVENT) {
		union xhci_trb *trb = &seg->trbs[TRBS_PER_SEGMENT - 1];

		trb->link.segment_ptr = cpu_to_le64(dma);
		trb->link.control = cpu_to_le32(LINK_TOGGLE | TRB_TYPE(TRB_LINK));
	}
	INIT_LIST_HEAD(&ring->td_list);
	xhci_initialize_ring_info(ring, 1);
	return ring;
dma_fail:
	kfree(seg);
seg_fail:
	kfree(ring);
	return NULL;
}

static int xhci_dbc_mem_init(struct xhci_dbc *dbc, gfp_t flags)
{
	int			ret;
	dma_addr_t		deq;
	u32			string_length;
	struct device		*dev = dbc->dev;

	/* Allocate various rings for events and transfers: */
	dbc->ring_evt = xhci_dbc_ring_alloc(dev, TYPE_EVENT, flags);
	if (!dbc->ring_evt)
		goto evt_fail;

	dbc->ring_in = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
	if (!dbc->ring_in)
		goto in_fail;

	dbc->ring_out = xhci_dbc_ring_alloc(dev, TYPE_BULK, flags);
	if (!dbc->ring_out)
		goto out_fail;

	/* Allocate and populate ERST: */
	ret = dbc_erst_alloc(dev, dbc->ring_evt, &dbc->erst, flags);
	if (ret)
		goto erst_fail;

	/* Allocate context data structure: */
	dbc->ctx = dbc_alloc_ctx(dev, flags); /* was sysdev, and is still */
	if (!dbc->ctx)
		goto ctx_fail;

	/* Allocate the string table: */
	dbc->string_size = sizeof(*dbc->string);
	dbc->string = dma_alloc_coherent(dev, dbc->string_size,
					 &dbc->string_dma, flags);
	if (!dbc->string)
		goto string_fail;

	/* Setup ERST register: */
	writel(dbc->erst.erst_size, &dbc->regs->ersts);

	lo_hi_writeq(dbc->erst.erst_dma_addr, &dbc->regs->erstba);
	deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
				   dbc->ring_evt->dequeue);
	lo_hi_writeq(deq, &dbc->regs->erdp);

	/* Setup strings and contexts: */
	string_length = xhci_dbc_populate_strings(dbc->string);
	xhci_dbc_init_contexts(dbc, string_length);

	xhci_dbc_eps_init(dbc);
	dbc->state = DS_INITIALIZED;

	return 0;

string_fail:
	dbc_free_ctx(dev, dbc->ctx);
	dbc->ctx = NULL;
ctx_fail:
	dbc_erst_free(dev, &dbc->erst);
erst_fail:
	dbc_ring_free(dev, dbc->ring_out);
	dbc->ring_out = NULL;
out_fail:
	dbc_ring_free(dev, dbc->ring_in);
	dbc->ring_in = NULL;
in_fail:
	dbc_ring_free(dev, dbc->ring_evt);
	dbc->ring_evt = NULL;
evt_fail:
	return -ENOMEM;
}

static void xhci_dbc_mem_cleanup(struct xhci_dbc *dbc)
{
	if (!dbc)
		return;

	xhci_dbc_eps_exit(dbc);

	dma_free_coherent(dbc->dev, dbc->string_size, dbc->string, dbc->string_dma);
	dbc->string = NULL;

	dbc_free_ctx(dbc->dev, dbc->ctx);
	dbc->ctx = NULL;

	dbc_erst_free(dbc->dev, &dbc->erst);
	dbc_ring_free(dbc->dev, dbc->ring_out);
	dbc_ring_free(dbc->dev, dbc->ring_in);
	dbc_ring_free(dbc->dev, dbc->ring_evt);
	dbc->ring_in = NULL;
	dbc->ring_out = NULL;
	dbc->ring_evt = NULL;
}

static int xhci_do_dbc_start(struct xhci_dbc *dbc)
{
	int			ret;
	u32			ctrl;

	if (dbc->state != DS_DISABLED)
		return -EINVAL;

	writel(0, &dbc->regs->control);
	ret = xhci_handshake(&dbc->regs->control,
			     DBC_CTRL_DBC_ENABLE,
			     0, 1000);
	if (ret)
		return ret;

	ret = xhci_dbc_mem_init(dbc, GFP_ATOMIC);
	if (ret)
		return ret;

	ctrl = readl(&dbc->regs->control);
	writel(ctrl | DBC_CTRL_DBC_ENABLE | DBC_CTRL_PORT_ENABLE,
	       &dbc->regs->control);
	ret = xhci_handshake(&dbc->regs->control,
			     DBC_CTRL_DBC_ENABLE,
			     DBC_CTRL_DBC_ENABLE, 1000);
	if (ret)
		return ret;

	dbc->state = DS_ENABLED;

	return 0;
}

static int xhci_do_dbc_stop(struct xhci_dbc *dbc)
{
	if (dbc->state == DS_DISABLED)
		return -EINVAL;

	writel(0, &dbc->regs->control);
	dbc->state = DS_DISABLED;

	return 0;
}

static int xhci_dbc_start(struct xhci_dbc *dbc)
{
	int			ret;
	unsigned long		flags;

	WARN_ON(!dbc);

	pm_runtime_get_sync(dbc->dev); /* note this was self.controller */

	spin_lock_irqsave(&dbc->lock, flags);
	ret = xhci_do_dbc_start(dbc);
	spin_unlock_irqrestore(&dbc->lock, flags);

	if (ret) {
		pm_runtime_put(dbc->dev); /* note this was self.controller */
		return ret;
	}

	return mod_delayed_work(system_wq, &dbc->event_work, 1);
}

static void xhci_dbc_stop(struct xhci_dbc *dbc)
{
	int ret;
	unsigned long		flags;

	WARN_ON(!dbc);

	switch (dbc->state) {
	case DS_DISABLED:
		return;
	case DS_CONFIGURED:
	case DS_STALLED:
		if (dbc->driver->disconnect)
			dbc->driver->disconnect(dbc);
		break;
	default:
		break;
	}

	cancel_delayed_work_sync(&dbc->event_work);

	spin_lock_irqsave(&dbc->lock, flags);
	ret = xhci_do_dbc_stop(dbc);
	spin_unlock_irqrestore(&dbc->lock, flags);
	if (ret)
		return;

	xhci_dbc_mem_cleanup(dbc);
	pm_runtime_put_sync(dbc->dev); /* note, was self.controller */
}

static void
dbc_handle_port_status(struct xhci_dbc *dbc, union xhci_trb *event)
{
	u32			portsc;

	portsc = readl(&dbc->regs->portsc);
	if (portsc & DBC_PORTSC_CONN_CHANGE)
		dev_info(dbc->dev, "DbC port connect change\n");

	if (portsc & DBC_PORTSC_RESET_CHANGE)
		dev_info(dbc->dev, "DbC port reset change\n");

	if (portsc & DBC_PORTSC_LINK_CHANGE)
		dev_info(dbc->dev, "DbC port link status change\n");

	if (portsc & DBC_PORTSC_CONFIG_CHANGE)
		dev_info(dbc->dev, "DbC config error change\n");

	/* Port reset change bit will be cleared in other place: */
	writel(portsc & ~DBC_PORTSC_RESET_CHANGE, &dbc->regs->portsc);
}

static void dbc_handle_xfer_event(struct xhci_dbc *dbc, union xhci_trb *event)
{
	struct dbc_ep		*dep;
	struct xhci_ring	*ring;
	int			ep_id;
	int			status;
	u32			comp_code;
	size_t			remain_length;
	struct dbc_request	*req = NULL, *r;

	comp_code	= GET_COMP_CODE(le32_to_cpu(event->generic.field[2]));
	remain_length	= EVENT_TRB_LEN(le32_to_cpu(event->generic.field[2]));
	ep_id		= TRB_TO_EP_ID(le32_to_cpu(event->generic.field[3]));
	dep		= (ep_id == EPID_OUT) ?
				get_out_ep(dbc) : get_in_ep(dbc);
	ring		= dep->ring;

	switch (comp_code) {
	case COMP_SUCCESS:
		remain_length = 0;
		fallthrough;
	case COMP_SHORT_PACKET:
		status = 0;
		break;
	case COMP_TRB_ERROR:
	case COMP_BABBLE_DETECTED_ERROR:
	case COMP_USB_TRANSACTION_ERROR:
	case COMP_STALL_ERROR:
		dev_warn(dbc->dev, "tx error %d detected\n", comp_code);
		status = -comp_code;
		break;
	default:
		dev_err(dbc->dev, "unknown tx error %d\n", comp_code);
		status = -comp_code;
		break;
	}

	/* Match the pending request: */
	list_for_each_entry(r, &dep->list_pending, list_pending) {
		if (r->trb_dma == event->trans_event.buffer) {
			req = r;
			break;
		}
	}

	if (!req) {
		dev_warn(dbc->dev, "no matched request\n");
		return;
	}

	trace_xhci_dbc_handle_transfer(ring, &req->trb->generic);

	ring->num_trbs_free++;
	req->actual = req->length - remain_length;
	xhci_dbc_giveback(req, status);
}

static void inc_evt_deq(struct xhci_ring *ring)
{
	/* If on the last TRB of the segment go back to the beginning */
	if (ring->dequeue == &ring->deq_seg->trbs[TRBS_PER_SEGMENT - 1]) {
		ring->cycle_state ^= 1;
		ring->dequeue = ring->deq_seg->trbs;
		return;
	}
	ring->dequeue++;
}

static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
{
	dma_addr_t		deq;
	struct dbc_ep		*dep;
	union xhci_trb		*evt;
	u32			ctrl, portsc;
	bool			update_erdp = false;

	/* DbC state machine: */
	switch (dbc->state) {
	case DS_DISABLED:
	case DS_INITIALIZED:

		return EVT_ERR;
	case DS_ENABLED:
		portsc = readl(&dbc->regs->portsc);
		if (portsc & DBC_PORTSC_CONN_STATUS) {
			dbc->state = DS_CONNECTED;
			dev_info(dbc->dev, "DbC connected\n");
		}

		return EVT_DONE;
	case DS_CONNECTED:
		ctrl = readl(&dbc->regs->control);
		if (ctrl & DBC_CTRL_DBC_RUN) {
			dbc->state = DS_CONFIGURED;
			dev_info(dbc->dev, "DbC configured\n");
			portsc = readl(&dbc->regs->portsc);
			writel(portsc, &dbc->regs->portsc);
			return EVT_GSER;
		}

		return EVT_DONE;
	case DS_CONFIGURED:
		/* Handle cable unplug event: */
		portsc = readl(&dbc->regs->portsc);
		if (!(portsc & DBC_PORTSC_PORT_ENABLED) &&
		    !(portsc & DBC_PORTSC_CONN_STATUS)) {
			dev_info(dbc->dev, "DbC cable unplugged\n");
			dbc->state = DS_ENABLED;
			xhci_dbc_flush_requests(dbc);

			return EVT_DISC;
		}

		/* Handle debug port reset event: */
		if (portsc & DBC_PORTSC_RESET_CHANGE) {
			dev_info(dbc->dev, "DbC port reset\n");
			writel(portsc, &dbc->regs->portsc);
			dbc->state = DS_ENABLED;
			xhci_dbc_flush_requests(dbc);

			return EVT_DISC;
		}

		/* Handle endpoint stall event: */
		ctrl = readl(&dbc->regs->control);
		if ((ctrl & DBC_CTRL_HALT_IN_TR) ||
		    (ctrl & DBC_CTRL_HALT_OUT_TR)) {
			dev_info(dbc->dev, "DbC Endpoint stall\n");
			dbc->state = DS_STALLED;

			if (ctrl & DBC_CTRL_HALT_IN_TR) {
				dep = get_in_ep(dbc);
				xhci_dbc_flush_endpoint_requests(dep);
			}

			if (ctrl & DBC_CTRL_HALT_OUT_TR) {
				dep = get_out_ep(dbc);
				xhci_dbc_flush_endpoint_requests(dep);
			}

			return EVT_DONE;
		}

		/* Clear DbC run change bit: */
		if (ctrl & DBC_CTRL_DBC_RUN_CHANGE) {
			writel(ctrl, &dbc->regs->control);
			ctrl = readl(&dbc->regs->control);
		}

		break;
	case DS_STALLED:
		ctrl = readl(&dbc->regs->control);
		if (!(ctrl & DBC_CTRL_HALT_IN_TR) &&
		    !(ctrl & DBC_CTRL_HALT_OUT_TR) &&
		    (ctrl & DBC_CTRL_DBC_RUN)) {
			dbc->state = DS_CONFIGURED;
			break;
		}

		return EVT_DONE;
	default:
		dev_err(dbc->dev, "Unknown DbC state %d\n", dbc->state);
		break;
	}

	/* Handle the events in the event ring: */
	evt = dbc->ring_evt->dequeue;
	while ((le32_to_cpu(evt->event_cmd.flags) & TRB_CYCLE) ==
			dbc->ring_evt->cycle_state) {
		/*
		 * Add a barrier between reading the cycle flag and any
		 * reads of the event's flags/data below:
		 */
		rmb();

		trace_xhci_dbc_handle_event(dbc->ring_evt, &evt->generic);

		switch (le32_to_cpu(evt->event_cmd.flags) & TRB_TYPE_BITMASK) {
		case TRB_TYPE(TRB_PORT_STATUS):
			dbc_handle_port_status(dbc, evt);
			break;
		case TRB_TYPE(TRB_TRANSFER):
			dbc_handle_xfer_event(dbc, evt);
			break;
		default:
			break;
		}

		inc_evt_deq(dbc->ring_evt);

		evt = dbc->ring_evt->dequeue;
		update_erdp = true;
	}

	/* Update event ring dequeue pointer: */
	if (update_erdp) {
		deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
					   dbc->ring_evt->dequeue);
		lo_hi_writeq(deq, &dbc->regs->erdp);
	}

	return EVT_DONE;
}

static void xhci_dbc_handle_events(struct work_struct *work)
{
	enum evtreturn		evtr;
	struct xhci_dbc		*dbc;
	unsigned long		flags;

	dbc = container_of(to_delayed_work(work), struct xhci_dbc, event_work);

	spin_lock_irqsave(&dbc->lock, flags);
	evtr = xhci_dbc_do_handle_events(dbc);
	spin_unlock_irqrestore(&dbc->lock, flags);

	switch (evtr) {
	case EVT_GSER:
		if (dbc->driver->configure)
			dbc->driver->configure(dbc);
		break;
	case EVT_DISC:
		if (dbc->driver->disconnect)
			dbc->driver->disconnect(dbc);
		break;
	case EVT_DONE:
		break;
	default:
		dev_info(dbc->dev, "stop handling dbc events\n");
		return;
	}

	mod_delayed_work(system_wq, &dbc->event_work, 1);
}

static const char * const dbc_state_strings[DS_MAX] = {
	[DS_DISABLED] = "disabled",
	[DS_INITIALIZED] = "initialized",
	[DS_ENABLED] = "enabled",
	[DS_CONNECTED] = "connected",
	[DS_CONFIGURED] = "configured",
	[DS_STALLED] = "stalled",
};

static ssize_t dbc_show(struct device *dev,
			struct device_attribute *attr,
			char *buf)
{
	struct xhci_dbc		*dbc;
	struct xhci_hcd		*xhci;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	if (dbc->state >= ARRAY_SIZE(dbc_state_strings))
		return sysfs_emit(buf, "unknown\n");

	return sysfs_emit(buf, "%s\n", dbc_state_strings[dbc->state]);
}

static ssize_t dbc_store(struct device *dev,
			 struct device_attribute *attr,
			 const char *buf, size_t count)
{
	struct xhci_hcd		*xhci;
	struct xhci_dbc		*dbc;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	if (sysfs_streq(buf, "enable"))
		xhci_dbc_start(dbc);
	else if (sysfs_streq(buf, "disable"))
		xhci_dbc_stop(dbc);
	else
		return -EINVAL;

	return count;
}

static ssize_t dbc_idVendor_show(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct xhci_dbc		*dbc;
	struct xhci_hcd		*xhci;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	return sysfs_emit(buf, "%04x\n", dbc->idVendor);
}

static ssize_t dbc_idVendor_store(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf, size_t size)
{
	struct xhci_dbc		*dbc;
	struct xhci_hcd		*xhci;
	void __iomem		*ptr;
	u16			value;
	u32			dev_info;
	int ret;

	ret = kstrtou16(buf, 0, &value);
	if (ret)
		return ret;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;
	if (dbc->state != DS_DISABLED)
		return -EBUSY;

	dbc->idVendor = value;
	ptr = &dbc->regs->devinfo1;
	dev_info = readl(ptr);
	dev_info = (dev_info & ~(0xffffu << 16)) | (value << 16);
	writel(dev_info, ptr);

	return size;
}

static ssize_t dbc_idProduct_show(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct xhci_dbc         *dbc;
	struct xhci_hcd         *xhci;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	return sysfs_emit(buf, "%04x\n", dbc->idProduct);
}

static ssize_t dbc_idProduct_store(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf, size_t size)
{
	struct xhci_dbc         *dbc;
	struct xhci_hcd         *xhci;
	void __iomem		*ptr;
	u32			dev_info;
	u16			value;
	int ret;

	ret = kstrtou16(buf, 0, &value);
	if (ret)
		return ret;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;
	if (dbc->state != DS_DISABLED)
		return -EBUSY;

	dbc->idProduct = value;
	ptr = &dbc->regs->devinfo2;
	dev_info = readl(ptr);
	dev_info = (dev_info & ~(0xffffu)) | value;
	writel(dev_info, ptr);
	return size;
}

static ssize_t dbc_bcdDevice_show(struct device *dev,
				   struct device_attribute *attr,
				   char *buf)
{
	struct xhci_dbc	*dbc;
	struct xhci_hcd	*xhci;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	return sysfs_emit(buf, "%04x\n", dbc->bcdDevice);
}

static ssize_t dbc_bcdDevice_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t size)
{
	struct xhci_dbc	*dbc;
	struct xhci_hcd	*xhci;
	void __iomem *ptr;
	u32 dev_info;
	u16 value;
	int ret;

	ret = kstrtou16(buf, 0, &value);
	if (ret)
		return ret;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;
	if (dbc->state != DS_DISABLED)
		return -EBUSY;

	dbc->bcdDevice = value;
	ptr = &dbc->regs->devinfo2;
	dev_info = readl(ptr);
	dev_info = (dev_info & ~(0xffffu << 16)) | (value << 16);
	writel(dev_info, ptr);

	return size;
}

static ssize_t dbc_bInterfaceProtocol_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct xhci_dbc	*dbc;
	struct xhci_hcd	*xhci;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;

	return sysfs_emit(buf, "%02x\n", dbc->bInterfaceProtocol);
}

static ssize_t dbc_bInterfaceProtocol_store(struct device *dev,
				  struct device_attribute *attr,
				  const char *buf, size_t size)
{
	struct xhci_dbc *dbc;
	struct xhci_hcd *xhci;
	void __iomem *ptr;
	u32 dev_info;
	u8 value;
	int ret;

	/* bInterfaceProtocol is 8 bit, but... */
	ret = kstrtou8(buf, 0, &value);
	if (ret)
		return ret;

	/* ...xhci only supports values 0 and 1 */
	if (value > 1)
		return -EINVAL;

	xhci = hcd_to_xhci(dev_get_drvdata(dev));
	dbc = xhci->dbc;
	if (dbc->state != DS_DISABLED)
		return -EBUSY;

	dbc->bInterfaceProtocol = value;
	ptr = &dbc->regs->devinfo1;
	dev_info = readl(ptr);
	dev_info = (dev_info & ~(0xffu)) | value;
	writel(dev_info, ptr);

	return size;
}

static DEVICE_ATTR_RW(dbc);
static DEVICE_ATTR_RW(dbc_idVendor);
static DEVICE_ATTR_RW(dbc_idProduct);
static DEVICE_ATTR_RW(dbc_bcdDevice);
static DEVICE_ATTR_RW(dbc_bInterfaceProtocol);

static struct attribute *dbc_dev_attrs[] = {
	&dev_attr_dbc.attr,
	&dev_attr_dbc_idVendor.attr,
	&dev_attr_dbc_idProduct.attr,
	&dev_attr_dbc_bcdDevice.attr,
	&dev_attr_dbc_bInterfaceProtocol.attr,
	NULL
};
ATTRIBUTE_GROUPS(dbc_dev);

struct xhci_dbc *
xhci_alloc_dbc(struct device *dev, void __iomem *base, const struct dbc_driver *driver)
{
	struct xhci_dbc		*dbc;
	int			ret;

	dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
	if (!dbc)
		return NULL;

	dbc->regs = base;
	dbc->dev = dev;
	dbc->driver = driver;
	dbc->idProduct = DBC_PRODUCT_ID;
	dbc->idVendor = DBC_VENDOR_ID;
	dbc->bcdDevice = DBC_DEVICE_REV;
	dbc->bInterfaceProtocol = DBC_PROTOCOL;

	if (readl(&dbc->regs->control) & DBC_CTRL_DBC_ENABLE)
		goto err;

	INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
	spin_lock_init(&dbc->lock);

	ret = sysfs_create_groups(&dev->kobj, dbc_dev_groups);
	if (ret)
		goto err;

	return dbc;
err:
	kfree(dbc);
	return NULL;
}

/* undo what xhci_alloc_dbc() did */
void xhci_dbc_remove(struct xhci_dbc *dbc)
{
	if (!dbc)
		return;
	/* stop hw, stop wq and call dbc->ops->stop() */
	xhci_dbc_stop(dbc);

	/* remove sysfs files */
	sysfs_remove_groups(&dbc->dev->kobj, dbc_dev_groups);

	kfree(dbc);
}


int xhci_create_dbc_dev(struct xhci_hcd *xhci)
{
	struct device		*dev;
	void __iomem		*base;
	int			ret;
	int			dbc_cap_offs;

	/* create all parameters needed resembling a dbc device */
	dev = xhci_to_hcd(xhci)->self.controller;
	base = &xhci->cap_regs->hc_capbase;

	dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
	if (!dbc_cap_offs)
		return -ENODEV;

	/* already allocated and in use */
	if (xhci->dbc)
		return -EBUSY;

	ret = xhci_dbc_tty_probe(dev, base + dbc_cap_offs, xhci);

	return ret;
}

void xhci_remove_dbc_dev(struct xhci_hcd *xhci)
{
	unsigned long		flags;

	if (!xhci->dbc)
		return;

	xhci_dbc_tty_remove(xhci->dbc);
	spin_lock_irqsave(&xhci->lock, flags);
	xhci->dbc = NULL;
	spin_unlock_irqrestore(&xhci->lock, flags);
}

#ifdef CONFIG_PM
int xhci_dbc_suspend(struct xhci_hcd *xhci)
{
	struct xhci_dbc		*dbc = xhci->dbc;

	if (!dbc)
		return 0;

	if (dbc->state == DS_CONFIGURED)
		dbc->resume_required = 1;

	xhci_dbc_stop(dbc);

	return 0;
}

int xhci_dbc_resume(struct xhci_hcd *xhci)
{
	int			ret = 0;
	struct xhci_dbc		*dbc = xhci->dbc;

	if (!dbc)
		return 0;

	if (dbc->resume_required) {
		dbc->resume_required = 0;
		xhci_dbc_start(dbc);
	}

	return ret;
}
#endif /* CONFIG_PM */

int xhci_dbc_init(void)
{
	return dbc_tty_init();
}

void xhci_dbc_exit(void)
{
	dbc_tty_exit();
}