summaryrefslogtreecommitdiffstats
path: root/drivers/usb/wusbcore/wa-xfer.c
blob: 489b47833e2c54ff7f1b225c35f1a51283ef2494 (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
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
/*
 * WUSB Wire Adapter
 * Data transfer and URB enqueing
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * How transfers work: get a buffer, break it up in segments (segment
 * size is a multiple of the maxpacket size). For each segment issue a
 * segment request (struct wa_xfer_*), then send the data buffer if
 * out or nothing if in (all over the DTO endpoint).
 *
 * For each submitted segment request, a notification will come over
 * the NEP endpoint and a transfer result (struct xfer_result) will
 * arrive in the DTI URB. Read it, get the xfer ID, see if there is
 * data coming (inbound transfer), schedule a read and handle it.
 *
 * Sounds simple, it is a pain to implement.
 *
 *
 * ENTRY POINTS
 *
 *   FIXME
 *
 * LIFE CYCLE / STATE DIAGRAM
 *
 *   FIXME
 *
 * THIS CODE IS DISGUSTING
 *
 *   Warned you are; it's my second try and still not happy with it.
 *
 * NOTES:
 *
 *   - No iso
 *
 *   - Supports DMA xfers, control, bulk and maybe interrupt
 *
 *   - Does not recycle unused rpipes
 *
 *     An rpipe is assigned to an endpoint the first time it is used,
 *     and then it's there, assigned, until the endpoint is disabled
 *     (destroyed [{h,d}wahc_op_ep_disable()]. The assignment of the
 *     rpipe to the endpoint is done under the wa->rpipe_sem semaphore
 *     (should be a mutex).
 *
 *     Two methods it could be done:
 *
 *     (a) set up a timer everytime an rpipe's use count drops to 1
 *         (which means unused) or when a transfer ends. Reset the
 *         timer when a xfer is queued. If the timer expires, release
 *         the rpipe [see rpipe_ep_disable()].
 *
 *     (b) when looking for free rpipes to attach [rpipe_get_by_ep()],
 *         when none are found go over the list, check their endpoint
 *         and their activity record (if no last-xfer-done-ts in the
 *         last x seconds) take it
 *
 *     However, due to the fact that we have a set of limited
 *     resources (max-segments-at-the-same-time per xfer,
 *     xfers-per-ripe, blocks-per-rpipe, rpipes-per-host), at the end
 *     we are going to have to rebuild all this based on an scheduler,
 *     to where we have a list of transactions to do and based on the
 *     availability of the different requried components (blocks,
 *     rpipes, segment slots, etc), we go scheduling them. Painful.
 */
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/hash.h>

#include "wa-hc.h"
#include "wusbhc.h"

enum {
	WA_SEGS_MAX = 255,
};

enum wa_seg_status {
	WA_SEG_NOTREADY,
	WA_SEG_READY,
	WA_SEG_DELAYED,
	WA_SEG_SUBMITTED,
	WA_SEG_PENDING,
	WA_SEG_DTI_PENDING,
	WA_SEG_DONE,
	WA_SEG_ERROR,
	WA_SEG_ABORTED,
};

static void wa_xfer_delayed_run(struct wa_rpipe *);

/*
 * Life cycle governed by 'struct urb' (the refcount of the struct is
 * that of the 'struct urb' and usb_free_urb() would free the whole
 * struct).
 */
struct wa_seg {
	struct urb urb;
	struct urb *dto_urb;		/* for data output? */
	struct list_head list_node;	/* for rpipe->req_list */
	struct wa_xfer *xfer;		/* out xfer */
	u8 index;			/* which segment we are */
	enum wa_seg_status status;
	ssize_t result;			/* bytes xfered or error */
	struct wa_xfer_hdr xfer_hdr;
	u8 xfer_extra[];		/* xtra space for xfer_hdr_ctl */
};

static void wa_seg_init(struct wa_seg *seg)
{
	/* usb_init_urb() repeats a lot of work, so we do it here */
	kref_init(&seg->urb.kref);
}

/*
 * Protected by xfer->lock
 *
 */
struct wa_xfer {
	struct kref refcnt;
	struct list_head list_node;
	spinlock_t lock;
	u32 id;

	struct wahc *wa;		/* Wire adapter we are plugged to */
	struct usb_host_endpoint *ep;
	struct urb *urb;		/* URB we are transfering for */
	struct wa_seg **seg;		/* transfer segments */
	u8 segs, segs_submitted, segs_done;
	unsigned is_inbound:1;
	unsigned is_dma:1;
	size_t seg_size;
	int result;

	gfp_t gfp;			/* allocation mask */

	struct wusb_dev *wusb_dev;	/* for activity timestamps */
};

static inline void wa_xfer_init(struct wa_xfer *xfer)
{
	kref_init(&xfer->refcnt);
	INIT_LIST_HEAD(&xfer->list_node);
	spin_lock_init(&xfer->lock);
}

/*
 * Destory a transfer structure
 *
 * Note that the xfer->seg[index] thingies follow the URB life cycle,
 * so we need to put them, not free them.
 */
static void wa_xfer_destroy(struct kref *_xfer)
{
	struct wa_xfer *xfer = container_of(_xfer, struct wa_xfer, refcnt);
	if (xfer->seg) {
		unsigned cnt;
		for (cnt = 0; cnt < xfer->segs; cnt++) {
			if (xfer->is_inbound)
				usb_put_urb(xfer->seg[cnt]->dto_urb);
			usb_put_urb(&xfer->seg[cnt]->urb);
		}
	}
	kfree(xfer);
}

static void wa_xfer_get(struct wa_xfer *xfer)
{
	kref_get(&xfer->refcnt);
}

static void wa_xfer_put(struct wa_xfer *xfer)
{
	kref_put(&xfer->refcnt, wa_xfer_destroy);
}

/*
 * xfer is referenced
 *
 * xfer->lock has to be unlocked
 *
 * We take xfer->lock for setting the result; this is a barrier
 * against drivers/usb/core/hcd.c:unlink1() being called after we call
 * usb_hcd_giveback_urb() and wa_urb_dequeue() trying to get a
 * reference to the transfer.
 */
static void wa_xfer_giveback(struct wa_xfer *xfer)
{
	unsigned long flags;

	spin_lock_irqsave(&xfer->wa->xfer_list_lock, flags);
	list_del_init(&xfer->list_node);
	spin_unlock_irqrestore(&xfer->wa->xfer_list_lock, flags);
	/* FIXME: segmentation broken -- kills DWA */
	wusbhc_giveback_urb(xfer->wa->wusb, xfer->urb, xfer->result);
	wa_put(xfer->wa);
	wa_xfer_put(xfer);
}

/*
 * xfer is referenced
 *
 * xfer->lock has to be unlocked
 */
static void wa_xfer_completion(struct wa_xfer *xfer)
{
	if (xfer->wusb_dev)
		wusb_dev_put(xfer->wusb_dev);
	rpipe_put(xfer->ep->hcpriv);
	wa_xfer_giveback(xfer);
}

/*
 * If transfer is done, wrap it up and return true
 *
 * xfer->lock has to be locked
 */
static unsigned __wa_xfer_is_done(struct wa_xfer *xfer)
{
	struct device *dev = &xfer->wa->usb_iface->dev;
	unsigned result, cnt;
	struct wa_seg *seg;
	struct urb *urb = xfer->urb;
	unsigned found_short = 0;

	result = xfer->segs_done == xfer->segs_submitted;
	if (result == 0)
		goto out;
	urb->actual_length = 0;
	for (cnt = 0; cnt < xfer->segs; cnt++) {
		seg = xfer->seg[cnt];
		switch (seg->status) {
		case WA_SEG_DONE:
			if (found_short && seg->result > 0) {
				dev_dbg(dev, "xfer %p#%u: bad short segments (%zu)\n",
					xfer, cnt, seg->result);
				urb->status = -EINVAL;
				goto out;
			}
			urb->actual_length += seg->result;
			if (seg->result < xfer->seg_size
			    && cnt != xfer->segs-1)
				found_short = 1;
			dev_dbg(dev, "xfer %p#%u: DONE short %d "
				"result %zu urb->actual_length %d\n",
				xfer, seg->index, found_short, seg->result,
				urb->actual_length);
			break;
		case WA_SEG_ERROR:
			xfer->result = seg->result;
			dev_dbg(dev, "xfer %p#%u: ERROR result %zu\n",
				xfer, seg->index, seg->result);
			goto out;
		case WA_SEG_ABORTED:
			dev_dbg(dev, "xfer %p#%u ABORTED: result %d\n",
				xfer, seg->index, urb->status);
			xfer->result = urb->status;
			goto out;
		default:
			dev_warn(dev, "xfer %p#%u: is_done bad state %d\n",
				 xfer, cnt, seg->status);
			xfer->result = -EINVAL;
			goto out;
		}
	}
	xfer->result = 0;
out:
	return result;
}

/*
 * Initialize a transfer's ID
 *
 * We need to use a sequential number; if we use the pointer or the
 * hash of the pointer, it can repeat over sequential transfers and
 * then it will confuse the HWA....wonder why in hell they put a 32
 * bit handle in there then.
 */
static void wa_xfer_id_init(struct wa_xfer *xfer)
{
	xfer->id = atomic_add_return(1, &xfer->wa->xfer_id_count);
}

/*
 * Return the xfer's ID associated with xfer
 *
 * Need to generate a
 */
static u32 wa_xfer_id(struct wa_xfer *xfer)
{
	return xfer->id;
}

/*
 * Search for a transfer list ID on the HCD's URB list
 *
 * For 32 bit architectures, we use the pointer itself; for 64 bits, a
 * 32-bit hash of the pointer.
 *
 * @returns NULL if not found.
 */
static struct wa_xfer *wa_xfer_get_by_id(struct wahc *wa, u32 id)
{
	unsigned long flags;
	struct wa_xfer *xfer_itr;
	spin_lock_irqsave(&wa->xfer_list_lock, flags);
	list_for_each_entry(xfer_itr, &wa->xfer_list, list_node) {
		if (id == xfer_itr->id) {
			wa_xfer_get(xfer_itr);
			goto out;
		}
	}
	xfer_itr = NULL;
out:
	spin_unlock_irqrestore(&wa->xfer_list_lock, flags);
	return xfer_itr;
}

struct wa_xfer_abort_buffer {
	struct urb urb;
	struct wa_xfer_abort cmd;
};

static void __wa_xfer_abort_cb(struct urb *urb)
{
	struct wa_xfer_abort_buffer *b = urb->context;
	usb_put_urb(&b->urb);
}

/*
 * Aborts an ongoing transaction
 *
 * Assumes the transfer is referenced and locked and in a submitted
 * state (mainly that there is an endpoint/rpipe assigned).
 *
 * The callback (see above) does nothing but freeing up the data by
 * putting the URB. Because the URB is allocated at the head of the
 * struct, the whole space we allocated is kfreed.
 *
 * We'll get an 'aborted transaction' xfer result on DTI, that'll
 * politely ignore because at this point the transaction has been
 * marked as aborted already.
 */
static void __wa_xfer_abort(struct wa_xfer *xfer)
{
	int result;
	struct device *dev = &xfer->wa->usb_iface->dev;
	struct wa_xfer_abort_buffer *b;
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	b = kmalloc(sizeof(*b), GFP_ATOMIC);
	if (b == NULL)
		goto error_kmalloc;
	b->cmd.bLength =  sizeof(b->cmd);
	b->cmd.bRequestType = WA_XFER_ABORT;
	b->cmd.wRPipe = rpipe->descr.wRPipeIndex;
	b->cmd.dwTransferID = wa_xfer_id(xfer);

	usb_init_urb(&b->urb);
	usb_fill_bulk_urb(&b->urb, xfer->wa->usb_dev,
		usb_sndbulkpipe(xfer->wa->usb_dev,
				xfer->wa->dto_epd->bEndpointAddress),
		&b->cmd, sizeof(b->cmd), __wa_xfer_abort_cb, b);
	result = usb_submit_urb(&b->urb, GFP_ATOMIC);
	if (result < 0)
		goto error_submit;
	return;				/* callback frees! */


error_submit:
	if (printk_ratelimit())
		dev_err(dev, "xfer %p: Can't submit abort request: %d\n",
			xfer, result);
	kfree(b);
error_kmalloc:
	return;

}

/*
 *
 * @returns < 0 on error, transfer segment request size if ok
 */
static ssize_t __wa_xfer_setup_sizes(struct wa_xfer *xfer,
				     enum wa_xfer_type *pxfer_type)
{
	ssize_t result;
	struct device *dev = &xfer->wa->usb_iface->dev;
	size_t maxpktsize;
	struct urb *urb = xfer->urb;
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	switch (rpipe->descr.bmAttribute & 0x3) {
	case USB_ENDPOINT_XFER_CONTROL:
		*pxfer_type = WA_XFER_TYPE_CTL;
		result = sizeof(struct wa_xfer_ctl);
		break;
	case USB_ENDPOINT_XFER_INT:
	case USB_ENDPOINT_XFER_BULK:
		*pxfer_type = WA_XFER_TYPE_BI;
		result = sizeof(struct wa_xfer_bi);
		break;
	case USB_ENDPOINT_XFER_ISOC:
		dev_err(dev, "FIXME: ISOC not implemented\n");
		result = -ENOSYS;
		goto error;
	default:
		/* never happens */
		BUG();
		result = -EINVAL;	/* shut gcc up */
	};
	xfer->is_inbound = urb->pipe & USB_DIR_IN ? 1 : 0;
	xfer->is_dma = urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? 1 : 0;
	xfer->seg_size = le16_to_cpu(rpipe->descr.wBlocks)
		* 1 << (xfer->wa->wa_descr->bRPipeBlockSize - 1);
	/* Compute the segment size and make sure it is a multiple of
	 * the maxpktsize (WUSB1.0[8.3.3.1])...not really too much of
	 * a check (FIXME) */
	maxpktsize = le16_to_cpu(rpipe->descr.wMaxPacketSize);
	if (xfer->seg_size < maxpktsize) {
		dev_err(dev, "HW BUG? seg_size %zu smaller than maxpktsize "
			"%zu\n", xfer->seg_size, maxpktsize);
		result = -EINVAL;
		goto error;
	}
	xfer->seg_size = (xfer->seg_size / maxpktsize) * maxpktsize;
	xfer->segs = (urb->transfer_buffer_length + xfer->seg_size - 1)
		/ xfer->seg_size;
	if (xfer->segs >= WA_SEGS_MAX) {
		dev_err(dev, "BUG? ops, number of segments %d bigger than %d\n",
			(int)(urb->transfer_buffer_length / xfer->seg_size),
			WA_SEGS_MAX);
		result = -EINVAL;
		goto error;
	}
	if (xfer->segs == 0 && *pxfer_type == WA_XFER_TYPE_CTL)
		xfer->segs = 1;
error:
	return result;
}

/* Fill in the common request header and xfer-type specific data. */
static void __wa_xfer_setup_hdr0(struct wa_xfer *xfer,
				 struct wa_xfer_hdr *xfer_hdr0,
				 enum wa_xfer_type xfer_type,
				 size_t xfer_hdr_size)
{
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;

	xfer_hdr0 = &xfer->seg[0]->xfer_hdr;
	xfer_hdr0->bLength = xfer_hdr_size;
	xfer_hdr0->bRequestType = xfer_type;
	xfer_hdr0->wRPipe = rpipe->descr.wRPipeIndex;
	xfer_hdr0->dwTransferID = wa_xfer_id(xfer);
	xfer_hdr0->bTransferSegment = 0;
	switch (xfer_type) {
	case WA_XFER_TYPE_CTL: {
		struct wa_xfer_ctl *xfer_ctl =
			container_of(xfer_hdr0, struct wa_xfer_ctl, hdr);
		xfer_ctl->bmAttribute = xfer->is_inbound ? 1 : 0;
		BUG_ON(xfer->urb->transfer_flags & URB_NO_SETUP_DMA_MAP
		       && xfer->urb->setup_packet == NULL);
		memcpy(&xfer_ctl->baSetupData, xfer->urb->setup_packet,
		       sizeof(xfer_ctl->baSetupData));
		break;
	}
	case WA_XFER_TYPE_BI:
		break;
	case WA_XFER_TYPE_ISO:
		printk(KERN_ERR "FIXME: ISOC not implemented\n");
	default:
		BUG();
	};
}

/*
 * Callback for the OUT data phase of the segment request
 *
 * Check wa_seg_cb(); most comments also apply here because this
 * function does almost the same thing and they work closely
 * together.
 *
 * If the seg request has failed but this DTO phase has suceeded,
 * wa_seg_cb() has already failed the segment and moved the
 * status to WA_SEG_ERROR, so this will go through 'case 0' and
 * effectively do nothing.
 */
static void wa_seg_dto_cb(struct urb *urb)
{
	struct wa_seg *seg = urb->context;
	struct wa_xfer *xfer = seg->xfer;
	struct wahc *wa;
	struct device *dev;
	struct wa_rpipe *rpipe;
	unsigned long flags;
	unsigned rpipe_ready = 0;
	u8 done = 0;

	switch (urb->status) {
	case 0:
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		dev_dbg(dev, "xfer %p#%u: data out done (%d bytes)\n",
			xfer, seg->index, urb->actual_length);
		if (seg->status < WA_SEG_PENDING)
			seg->status = WA_SEG_PENDING;
		seg->result = urb->actual_length;
		spin_unlock_irqrestore(&xfer->lock, flags);
		break;
	case -ECONNRESET:	/* URB unlinked; no need to do anything */
	case -ENOENT:		/* as it was done by the who unlinked us */
		break;
	default:		/* Other errors ... */
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		rpipe = xfer->ep->hcpriv;
		dev_dbg(dev, "xfer %p#%u: data out error %d\n",
			xfer, seg->index, urb->status);
		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
			    EDC_ERROR_TIMEFRAME)){
			dev_err(dev, "DTO: URB max acceptable errors "
				"exceeded, resetting device\n");
			wa_reset_all(wa);
		}
		if (seg->status != WA_SEG_ERROR) {
			seg->status = WA_SEG_ERROR;
			seg->result = urb->status;
			xfer->segs_done++;
			__wa_xfer_abort(xfer);
			rpipe_ready = rpipe_avail_inc(rpipe);
			done = __wa_xfer_is_done(xfer);
		}
		spin_unlock_irqrestore(&xfer->lock, flags);
		if (done)
			wa_xfer_completion(xfer);
		if (rpipe_ready)
			wa_xfer_delayed_run(rpipe);
	}
}

/*
 * Callback for the segment request
 *
 * If successful transition state (unless already transitioned or
 * outbound transfer); otherwise, take a note of the error, mark this
 * segment done and try completion.
 *
 * Note we don't access until we are sure that the transfer hasn't
 * been cancelled (ECONNRESET, ENOENT), which could mean that
 * seg->xfer could be already gone.
 *
 * We have to check before setting the status to WA_SEG_PENDING
 * because sometimes the xfer result callback arrives before this
 * callback (geeeeeeze), so it might happen that we are already in
 * another state. As well, we don't set it if the transfer is inbound,
 * as in that case, wa_seg_dto_cb will do it when the OUT data phase
 * finishes.
 */
static void wa_seg_cb(struct urb *urb)
{
	struct wa_seg *seg = urb->context;
	struct wa_xfer *xfer = seg->xfer;
	struct wahc *wa;
	struct device *dev;
	struct wa_rpipe *rpipe;
	unsigned long flags;
	unsigned rpipe_ready;
	u8 done = 0;

	switch (urb->status) {
	case 0:
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		dev_dbg(dev, "xfer %p#%u: request done\n", xfer, seg->index);
		if (xfer->is_inbound && seg->status < WA_SEG_PENDING)
			seg->status = WA_SEG_PENDING;
		spin_unlock_irqrestore(&xfer->lock, flags);
		break;
	case -ECONNRESET:	/* URB unlinked; no need to do anything */
	case -ENOENT:		/* as it was done by the who unlinked us */
		break;
	default:		/* Other errors ... */
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		rpipe = xfer->ep->hcpriv;
		if (printk_ratelimit())
			dev_err(dev, "xfer %p#%u: request error %d\n",
				xfer, seg->index, urb->status);
		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
			    EDC_ERROR_TIMEFRAME)){
			dev_err(dev, "DTO: URB max acceptable errors "
				"exceeded, resetting device\n");
			wa_reset_all(wa);
		}
		usb_unlink_urb(seg->dto_urb);
		seg->status = WA_SEG_ERROR;
		seg->result = urb->status;
		xfer->segs_done++;
		__wa_xfer_abort(xfer);
		rpipe_ready = rpipe_avail_inc(rpipe);
		done = __wa_xfer_is_done(xfer);
		spin_unlock_irqrestore(&xfer->lock, flags);
		if (done)
			wa_xfer_completion(xfer);
		if (rpipe_ready)
			wa_xfer_delayed_run(rpipe);
	}
}

/*
 * Allocate the segs array and initialize each of them
 *
 * The segments are freed by wa_xfer_destroy() when the xfer use count
 * drops to zero; however, because each segment is given the same life
 * cycle as the USB URB it contains, it is actually freed by
 * usb_put_urb() on the contained USB URB (twisted, eh?).
 */
static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
{
	int result, cnt;
	size_t alloc_size = sizeof(*xfer->seg[0])
		- sizeof(xfer->seg[0]->xfer_hdr) + xfer_hdr_size;
	struct usb_device *usb_dev = xfer->wa->usb_dev;
	const struct usb_endpoint_descriptor *dto_epd = xfer->wa->dto_epd;
	struct wa_seg *seg;
	size_t buf_itr, buf_size, buf_itr_size;

	result = -ENOMEM;
	xfer->seg = kcalloc(xfer->segs, sizeof(xfer->seg[0]), GFP_ATOMIC);
	if (xfer->seg == NULL)
		goto error_segs_kzalloc;
	buf_itr = 0;
	buf_size = xfer->urb->transfer_buffer_length;
	for (cnt = 0; cnt < xfer->segs; cnt++) {
		seg = xfer->seg[cnt] = kzalloc(alloc_size, GFP_ATOMIC);
		if (seg == NULL)
			goto error_seg_kzalloc;
		wa_seg_init(seg);
		seg->xfer = xfer;
		seg->index = cnt;
		usb_fill_bulk_urb(&seg->urb, usb_dev,
				  usb_sndbulkpipe(usb_dev,
						  dto_epd->bEndpointAddress),
				  &seg->xfer_hdr, xfer_hdr_size,
				  wa_seg_cb, seg);
		buf_itr_size = buf_size > xfer->seg_size ?
			xfer->seg_size : buf_size;
		if (xfer->is_inbound == 0 && buf_size > 0) {
			seg->dto_urb = usb_alloc_urb(0, GFP_ATOMIC);
			if (seg->dto_urb == NULL)
				goto error_dto_alloc;
			usb_fill_bulk_urb(
				seg->dto_urb, usb_dev,
				usb_sndbulkpipe(usb_dev,
						dto_epd->bEndpointAddress),
				NULL, 0, wa_seg_dto_cb, seg);
			if (xfer->is_dma) {
				seg->dto_urb->transfer_dma =
					xfer->urb->transfer_dma + buf_itr;
				seg->dto_urb->transfer_flags |=
					URB_NO_TRANSFER_DMA_MAP;
			} else
				seg->dto_urb->transfer_buffer =
					xfer->urb->transfer_buffer + buf_itr;
			seg->dto_urb->transfer_buffer_length = buf_itr_size;
		}
		seg->status = WA_SEG_READY;
		buf_itr += buf_itr_size;
		buf_size -= buf_itr_size;
	}
	return 0;

error_dto_alloc:
	kfree(xfer->seg[cnt]);
	cnt--;
error_seg_kzalloc:
	/* use the fact that cnt is left at were it failed */
	for (; cnt > 0; cnt--) {
		if (xfer->is_inbound == 0)
			kfree(xfer->seg[cnt]->dto_urb);
		kfree(xfer->seg[cnt]);
	}
error_segs_kzalloc:
	return result;
}

/*
 * Allocates all the stuff needed to submit a transfer
 *
 * Breaks the whole data buffer in a list of segments, each one has a
 * structure allocated to it and linked in xfer->seg[index]
 *
 * FIXME: merge setup_segs() and the last part of this function, no
 *        need to do two for loops when we could run everything in a
 *        single one
 */
static int __wa_xfer_setup(struct wa_xfer *xfer, struct urb *urb)
{
	int result;
	struct device *dev = &xfer->wa->usb_iface->dev;
	enum wa_xfer_type xfer_type = 0; /* shut up GCC */
	size_t xfer_hdr_size, cnt, transfer_size;
	struct wa_xfer_hdr *xfer_hdr0, *xfer_hdr;

	result = __wa_xfer_setup_sizes(xfer, &xfer_type);
	if (result < 0)
		goto error_setup_sizes;
	xfer_hdr_size = result;
	result = __wa_xfer_setup_segs(xfer, xfer_hdr_size);
	if (result < 0) {
		dev_err(dev, "xfer %p: Failed to allocate %d segments: %d\n",
			xfer, xfer->segs, result);
		goto error_setup_segs;
	}
	/* Fill the first header */
	xfer_hdr0 = &xfer->seg[0]->xfer_hdr;
	wa_xfer_id_init(xfer);
	__wa_xfer_setup_hdr0(xfer, xfer_hdr0, xfer_type, xfer_hdr_size);

	/* Fill remainig headers */
	xfer_hdr = xfer_hdr0;
	transfer_size = urb->transfer_buffer_length;
	xfer_hdr0->dwTransferLength = transfer_size > xfer->seg_size ?
		xfer->seg_size : transfer_size;
	transfer_size -=  xfer->seg_size;
	for (cnt = 1; cnt < xfer->segs; cnt++) {
		xfer_hdr = &xfer->seg[cnt]->xfer_hdr;
		memcpy(xfer_hdr, xfer_hdr0, xfer_hdr_size);
		xfer_hdr->bTransferSegment = cnt;
		xfer_hdr->dwTransferLength = transfer_size > xfer->seg_size ?
			cpu_to_le32(xfer->seg_size)
			: cpu_to_le32(transfer_size);
		xfer->seg[cnt]->status = WA_SEG_READY;
		transfer_size -=  xfer->seg_size;
	}
	xfer_hdr->bTransferSegment |= 0x80;	/* this is the last segment */
	result = 0;
error_setup_segs:
error_setup_sizes:
	return result;
}

/*
 *
 *
 * rpipe->seg_lock is held!
 */
static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer,
			   struct wa_seg *seg)
{
	int result;
	result = usb_submit_urb(&seg->urb, GFP_ATOMIC);
	if (result < 0) {
		printk(KERN_ERR "xfer %p#%u: REQ submit failed: %d\n",
		       xfer, seg->index, result);
		goto error_seg_submit;
	}
	if (seg->dto_urb) {
		result = usb_submit_urb(seg->dto_urb, GFP_ATOMIC);
		if (result < 0) {
			printk(KERN_ERR "xfer %p#%u: DTO submit failed: %d\n",
			       xfer, seg->index, result);
			goto error_dto_submit;
		}
	}
	seg->status = WA_SEG_SUBMITTED;
	rpipe_avail_dec(rpipe);
	return 0;

error_dto_submit:
	usb_unlink_urb(&seg->urb);
error_seg_submit:
	seg->status = WA_SEG_ERROR;
	seg->result = result;
	return result;
}

/*
 * Execute more queued request segments until the maximum concurrent allowed
 *
 * The ugly unlock/lock sequence on the error path is needed as the
 * xfer->lock normally nests the seg_lock and not viceversa.
 *
 */
static void wa_xfer_delayed_run(struct wa_rpipe *rpipe)
{
	int result;
	struct device *dev = &rpipe->wa->usb_iface->dev;
	struct wa_seg *seg;
	struct wa_xfer *xfer;
	unsigned long flags;

	spin_lock_irqsave(&rpipe->seg_lock, flags);
	while (atomic_read(&rpipe->segs_available) > 0
	      && !list_empty(&rpipe->seg_list)) {
		seg = list_entry(rpipe->seg_list.next, struct wa_seg,
				 list_node);
		list_del(&seg->list_node);
		xfer = seg->xfer;
		result = __wa_seg_submit(rpipe, xfer, seg);
		dev_dbg(dev, "xfer %p#%u submitted from delayed [%d segments available] %d\n",
			xfer, seg->index, atomic_read(&rpipe->segs_available), result);
		if (unlikely(result < 0)) {
			spin_unlock_irqrestore(&rpipe->seg_lock, flags);
			spin_lock_irqsave(&xfer->lock, flags);
			__wa_xfer_abort(xfer);
			xfer->segs_done++;
			spin_unlock_irqrestore(&xfer->lock, flags);
			spin_lock_irqsave(&rpipe->seg_lock, flags);
		}
	}
	spin_unlock_irqrestore(&rpipe->seg_lock, flags);
}

/*
 *
 * xfer->lock is taken
 *
 * On failure submitting we just stop submitting and return error;
 * wa_urb_enqueue_b() will execute the completion path
 */
static int __wa_xfer_submit(struct wa_xfer *xfer)
{
	int result;
	struct wahc *wa = xfer->wa;
	struct device *dev = &wa->usb_iface->dev;
	unsigned cnt;
	struct wa_seg *seg;
	unsigned long flags;
	struct wa_rpipe *rpipe = xfer->ep->hcpriv;
	size_t maxrequests = le16_to_cpu(rpipe->descr.wRequests);
	u8 available;
	u8 empty;

	spin_lock_irqsave(&wa->xfer_list_lock, flags);
	list_add_tail(&xfer->list_node, &wa->xfer_list);
	spin_unlock_irqrestore(&wa->xfer_list_lock, flags);

	BUG_ON(atomic_read(&rpipe->segs_available) > maxrequests);
	result = 0;
	spin_lock_irqsave(&rpipe->seg_lock, flags);
	for (cnt = 0; cnt < xfer->segs; cnt++) {
		available = atomic_read(&rpipe->segs_available);
		empty = list_empty(&rpipe->seg_list);
		seg = xfer->seg[cnt];
		dev_dbg(dev, "xfer %p#%u: available %u empty %u (%s)\n",
			xfer, cnt, available, empty,
			available == 0 || !empty ? "delayed" : "submitted");
		if (available == 0 || !empty) {
			dev_dbg(dev, "xfer %p#%u: delayed\n", xfer, cnt);
			seg->status = WA_SEG_DELAYED;
			list_add_tail(&seg->list_node, &rpipe->seg_list);
		} else {
			result = __wa_seg_submit(rpipe, xfer, seg);
			if (result < 0) {
				__wa_xfer_abort(xfer);
				goto error_seg_submit;
			}
		}
		xfer->segs_submitted++;
	}
error_seg_submit:
	spin_unlock_irqrestore(&rpipe->seg_lock, flags);
	return result;
}

/*
 * Second part of a URB/transfer enqueuement
 *
 * Assumes this comes from wa_urb_enqueue() [maybe through
 * wa_urb_enqueue_run()]. At this point:
 *
 * xfer->wa	filled and refcounted
 * xfer->ep	filled with rpipe refcounted if
 *              delayed == 0
 * xfer->urb 	filled and refcounted (this is the case when called
 *              from wa_urb_enqueue() as we come from usb_submit_urb()
 *              and when called by wa_urb_enqueue_run(), as we took an
 *              extra ref dropped by _run() after we return).
 * xfer->gfp	filled
 *
 * If we fail at __wa_xfer_submit(), then we just check if we are done
 * and if so, we run the completion procedure. However, if we are not
 * yet done, we do nothing and wait for the completion handlers from
 * the submitted URBs or from the xfer-result path to kick in. If xfer
 * result never kicks in, the xfer will timeout from the USB code and
 * dequeue() will be called.
 */
static void wa_urb_enqueue_b(struct wa_xfer *xfer)
{
	int result;
	unsigned long flags;
	struct urb *urb = xfer->urb;
	struct wahc *wa = xfer->wa;
	struct wusbhc *wusbhc = wa->wusb;
	struct wusb_dev *wusb_dev;
	unsigned done;

	result = rpipe_get_by_ep(wa, xfer->ep, urb, xfer->gfp);
	if (result < 0)
		goto error_rpipe_get;
	result = -ENODEV;
	/* FIXME: segmentation broken -- kills DWA */
	mutex_lock(&wusbhc->mutex);		/* get a WUSB dev */
	if (urb->dev == NULL) {
		mutex_unlock(&wusbhc->mutex);
		goto error_dev_gone;
	}
	wusb_dev = __wusb_dev_get_by_usb_dev(wusbhc, urb->dev);
	if (wusb_dev == NULL) {
		mutex_unlock(&wusbhc->mutex);
		goto error_dev_gone;
	}
	mutex_unlock(&wusbhc->mutex);

	spin_lock_irqsave(&xfer->lock, flags);
	xfer->wusb_dev = wusb_dev;
	result = urb->status;
	if (urb->status != -EINPROGRESS)
		goto error_dequeued;

	result = __wa_xfer_setup(xfer, urb);
	if (result < 0)
		goto error_xfer_setup;
	result = __wa_xfer_submit(xfer);
	if (result < 0)
		goto error_xfer_submit;
	spin_unlock_irqrestore(&xfer->lock, flags);
	return;

	/* this is basically wa_xfer_completion() broken up wa_xfer_giveback()
	 * does a wa_xfer_put() that will call wa_xfer_destroy() and clean
	 * upundo setup().
	 */
error_xfer_setup:
error_dequeued:
	spin_unlock_irqrestore(&xfer->lock, flags);
	/* FIXME: segmentation broken, kills DWA */
	if (wusb_dev)
		wusb_dev_put(wusb_dev);
error_dev_gone:
	rpipe_put(xfer->ep->hcpriv);
error_rpipe_get:
	xfer->result = result;
	wa_xfer_giveback(xfer);
	return;

error_xfer_submit:
	done = __wa_xfer_is_done(xfer);
	xfer->result = result;
	spin_unlock_irqrestore(&xfer->lock, flags);
	if (done)
		wa_xfer_completion(xfer);
}

/*
 * Execute the delayed transfers in the Wire Adapter @wa
 *
 * We need to be careful here, as dequeue() could be called in the
 * middle.  That's why we do the whole thing under the
 * wa->xfer_list_lock. If dequeue() jumps in, it first locks urb->lock
 * and then checks the list -- so as we would be acquiring in inverse
 * order, we just drop the lock once we have the xfer and reacquire it
 * later.
 */
void wa_urb_enqueue_run(struct work_struct *ws)
{
	struct wahc *wa = container_of(ws, struct wahc, xfer_work);
	struct wa_xfer *xfer, *next;
	struct urb *urb;

	spin_lock_irq(&wa->xfer_list_lock);
	list_for_each_entry_safe(xfer, next, &wa->xfer_delayed_list,
				 list_node) {
		list_del_init(&xfer->list_node);
		spin_unlock_irq(&wa->xfer_list_lock);

		urb = xfer->urb;
		wa_urb_enqueue_b(xfer);
		usb_put_urb(urb);	/* taken when queuing */

		spin_lock_irq(&wa->xfer_list_lock);
	}
	spin_unlock_irq(&wa->xfer_list_lock);
}
EXPORT_SYMBOL_GPL(wa_urb_enqueue_run);

/*
 * Submit a transfer to the Wire Adapter in a delayed way
 *
 * The process of enqueuing involves possible sleeps() [see
 * enqueue_b(), for the rpipe_get() and the mutex_lock()]. If we are
 * in an atomic section, we defer the enqueue_b() call--else we call direct.
 *
 * @urb: We own a reference to it done by the HCI Linux USB stack that
 *       will be given up by calling usb_hcd_giveback_urb() or by
 *       returning error from this function -> ergo we don't have to
 *       refcount it.
 */
int wa_urb_enqueue(struct wahc *wa, struct usb_host_endpoint *ep,
		   struct urb *urb, gfp_t gfp)
{
	int result;
	struct device *dev = &wa->usb_iface->dev;
	struct wa_xfer *xfer;
	unsigned long my_flags;
	unsigned cant_sleep = irqs_disabled() | in_atomic();

	if (urb->transfer_buffer == NULL
	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
	    && urb->transfer_buffer_length != 0) {
		dev_err(dev, "BUG? urb %p: NULL xfer buffer & NODMA\n", urb);
		dump_stack();
	}

	result = -ENOMEM;
	xfer = kzalloc(sizeof(*xfer), gfp);
	if (xfer == NULL)
		goto error_kmalloc;

	result = -ENOENT;
	if (urb->status != -EINPROGRESS)	/* cancelled */
		goto error_dequeued;		/* before starting? */
	wa_xfer_init(xfer);
	xfer->wa = wa_get(wa);
	xfer->urb = urb;
	xfer->gfp = gfp;
	xfer->ep = ep;
	urb->hcpriv = xfer;

	dev_dbg(dev, "xfer %p urb %p pipe 0x%02x [%d bytes] %s %s %s\n",
		xfer, urb, urb->pipe, urb->transfer_buffer_length,
		urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? "dma" : "nodma",
		urb->pipe & USB_DIR_IN ? "inbound" : "outbound",
		cant_sleep ? "deferred" : "inline");

	if (cant_sleep) {
		usb_get_urb(urb);
		spin_lock_irqsave(&wa->xfer_list_lock, my_flags);
		list_add_tail(&xfer->list_node, &wa->xfer_delayed_list);
		spin_unlock_irqrestore(&wa->xfer_list_lock, my_flags);
		queue_work(wusbd, &wa->xfer_work);
	} else {
		wa_urb_enqueue_b(xfer);
	}
	return 0;

error_dequeued:
	kfree(xfer);
error_kmalloc:
	return result;
}
EXPORT_SYMBOL_GPL(wa_urb_enqueue);

/*
 * Dequeue a URB and make sure uwb_hcd_giveback_urb() [completion
 * handler] is called.
 *
 * Until a transfer goes successfully through wa_urb_enqueue() it
 * needs to be dequeued with completion calling; when stuck in delayed
 * or before wa_xfer_setup() is called, we need to do completion.
 *
 *  not setup  If there is no hcpriv yet, that means that that enqueue
 *             still had no time to set the xfer up. Because
 *             urb->status should be other than -EINPROGRESS,
 *             enqueue() will catch that and bail out.
 *
 * If the transfer has gone through setup, we just need to clean it
 * up. If it has gone through submit(), we have to abort it [with an
 * asynch request] and then make sure we cancel each segment.
 *
 */
int wa_urb_dequeue(struct wahc *wa, struct urb *urb)
{
	unsigned long flags, flags2;
	struct wa_xfer *xfer;
	struct wa_seg *seg;
	struct wa_rpipe *rpipe;
	unsigned cnt;
	unsigned rpipe_ready = 0;

	xfer = urb->hcpriv;
	if (xfer == NULL) {
		/* NOthing setup yet enqueue will see urb->status !=
		 * -EINPROGRESS (by hcd layer) and bail out with
		 * error, no need to do completion
		 */
		BUG_ON(urb->status == -EINPROGRESS);
		goto out;
	}
	spin_lock_irqsave(&xfer->lock, flags);
	rpipe = xfer->ep->hcpriv;
	/* Check the delayed list -> if there, release and complete */
	spin_lock_irqsave(&wa->xfer_list_lock, flags2);
	if (!list_empty(&xfer->list_node) && xfer->seg == NULL)
		goto dequeue_delayed;
	spin_unlock_irqrestore(&wa->xfer_list_lock, flags2);
	if (xfer->seg == NULL)  	/* still hasn't reached */
		goto out_unlock;	/* setup(), enqueue_b() completes */
	/* Ok, the xfer is in flight already, it's been setup and submitted.*/
	__wa_xfer_abort(xfer);
	for (cnt = 0; cnt < xfer->segs; cnt++) {
		seg = xfer->seg[cnt];
		switch (seg->status) {
		case WA_SEG_NOTREADY:
		case WA_SEG_READY:
			printk(KERN_ERR "xfer %p#%u: dequeue bad state %u\n",
			       xfer, cnt, seg->status);
			WARN_ON(1);
			break;
		case WA_SEG_DELAYED:
			seg->status = WA_SEG_ABORTED;
			spin_lock_irqsave(&rpipe->seg_lock, flags2);
			list_del(&seg->list_node);
			xfer->segs_done++;
			rpipe_ready = rpipe_avail_inc(rpipe);
			spin_unlock_irqrestore(&rpipe->seg_lock, flags2);
			break;
		case WA_SEG_SUBMITTED:
			seg->status = WA_SEG_ABORTED;
			usb_unlink_urb(&seg->urb);
			if (xfer->is_inbound == 0)
				usb_unlink_urb(seg->dto_urb);
			xfer->segs_done++;
			rpipe_ready = rpipe_avail_inc(rpipe);
			break;
		case WA_SEG_PENDING:
			seg->status = WA_SEG_ABORTED;
			xfer->segs_done++;
			rpipe_ready = rpipe_avail_inc(rpipe);
			break;
		case WA_SEG_DTI_PENDING:
			usb_unlink_urb(wa->dti_urb);
			seg->status = WA_SEG_ABORTED;
			xfer->segs_done++;
			rpipe_ready = rpipe_avail_inc(rpipe);
			break;
		case WA_SEG_DONE:
		case WA_SEG_ERROR:
		case WA_SEG_ABORTED:
			break;
		}
	}
	xfer->result = urb->status;	/* -ENOENT or -ECONNRESET */
	__wa_xfer_is_done(xfer);
	spin_unlock_irqrestore(&xfer->lock, flags);
	wa_xfer_completion(xfer);
	if (rpipe_ready)
		wa_xfer_delayed_run(rpipe);
	return 0;

out_unlock:
	spin_unlock_irqrestore(&xfer->lock, flags);
out:
	return 0;

dequeue_delayed:
	list_del_init(&xfer->list_node);
	spin_unlock_irqrestore(&wa->xfer_list_lock, flags2);
	xfer->result = urb->status;
	spin_unlock_irqrestore(&xfer->lock, flags);
	wa_xfer_giveback(xfer);
	usb_put_urb(urb);		/* we got a ref in enqueue() */
	return 0;
}
EXPORT_SYMBOL_GPL(wa_urb_dequeue);

/*
 * Translation from WA status codes (WUSB1.0 Table 8.15) to errno
 * codes
 *
 * Positive errno values are internal inconsistencies and should be
 * flagged louder. Negative are to be passed up to the user in the
 * normal way.
 *
 * @status: USB WA status code -- high two bits are stripped.
 */
static int wa_xfer_status_to_errno(u8 status)
{
	int errno;
	u8 real_status = status;
	static int xlat[] = {
		[WA_XFER_STATUS_SUCCESS] = 		0,
		[WA_XFER_STATUS_HALTED] = 		-EPIPE,
		[WA_XFER_STATUS_DATA_BUFFER_ERROR] = 	-ENOBUFS,
		[WA_XFER_STATUS_BABBLE] = 		-EOVERFLOW,
		[WA_XFER_RESERVED] = 			EINVAL,
		[WA_XFER_STATUS_NOT_FOUND] =		0,
		[WA_XFER_STATUS_INSUFFICIENT_RESOURCE] = -ENOMEM,
		[WA_XFER_STATUS_TRANSACTION_ERROR] = 	-EILSEQ,
		[WA_XFER_STATUS_ABORTED] = 		-EINTR,
		[WA_XFER_STATUS_RPIPE_NOT_READY] = 	EINVAL,
		[WA_XFER_INVALID_FORMAT] = 		EINVAL,
		[WA_XFER_UNEXPECTED_SEGMENT_NUMBER] = 	EINVAL,
		[WA_XFER_STATUS_RPIPE_TYPE_MISMATCH] = 	EINVAL,
	};
	status &= 0x3f;

	if (status == 0)
		return 0;
	if (status >= ARRAY_SIZE(xlat)) {
		if (printk_ratelimit())
			printk(KERN_ERR "%s(): BUG? "
			       "Unknown WA transfer status 0x%02x\n",
			       __func__, real_status);
		return -EINVAL;
	}
	errno = xlat[status];
	if (unlikely(errno > 0)) {
		if (printk_ratelimit())
			printk(KERN_ERR "%s(): BUG? "
			       "Inconsistent WA status: 0x%02x\n",
			       __func__, real_status);
		errno = -errno;
	}
	return errno;
}

/*
 * Process a xfer result completion message
 *
 * inbound transfers: need to schedule a DTI read
 *
 * FIXME: this functio needs to be broken up in parts
 */
static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer)
{
	int result;
	struct device *dev = &wa->usb_iface->dev;
	unsigned long flags;
	u8 seg_idx;
	struct wa_seg *seg;
	struct wa_rpipe *rpipe;
	struct wa_xfer_result *xfer_result = wa->xfer_result;
	u8 done = 0;
	u8 usb_status;
	unsigned rpipe_ready = 0;

	spin_lock_irqsave(&xfer->lock, flags);
	seg_idx = xfer_result->bTransferSegment & 0x7f;
	if (unlikely(seg_idx >= xfer->segs))
		goto error_bad_seg;
	seg = xfer->seg[seg_idx];
	rpipe = xfer->ep->hcpriv;
	usb_status = xfer_result->bTransferStatus;
	dev_dbg(dev, "xfer %p#%u: bTransferStatus 0x%02x (seg %u)\n",
		xfer, seg_idx, usb_status, seg->status);
	if (seg->status == WA_SEG_ABORTED
	    || seg->status == WA_SEG_ERROR)	/* already handled */
		goto segment_aborted;
	if (seg->status == WA_SEG_SUBMITTED)	/* ops, got here */
		seg->status = WA_SEG_PENDING;	/* before wa_seg{_dto}_cb() */
	if (seg->status != WA_SEG_PENDING) {
		if (printk_ratelimit())
			dev_err(dev, "xfer %p#%u: Bad segment state %u\n",
				xfer, seg_idx, seg->status);
		seg->status = WA_SEG_PENDING;	/* workaround/"fix" it */
	}
	if (usb_status & 0x80) {
		seg->result = wa_xfer_status_to_errno(usb_status);
		dev_err(dev, "DTI: xfer %p#%u failed (0x%02x)\n",
			xfer, seg->index, usb_status);
		goto error_complete;
	}
	/* FIXME: we ignore warnings, tally them for stats */
	if (usb_status & 0x40) 		/* Warning?... */
		usb_status = 0;		/* ... pass */
	if (xfer->is_inbound) {	/* IN data phase: read to buffer */
		seg->status = WA_SEG_DTI_PENDING;
		BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);
		if (xfer->is_dma) {
			wa->buf_in_urb->transfer_dma =
				xfer->urb->transfer_dma
				+ seg_idx * xfer->seg_size;
			wa->buf_in_urb->transfer_flags
				|= URB_NO_TRANSFER_DMA_MAP;
		} else {
			wa->buf_in_urb->transfer_buffer =
				xfer->urb->transfer_buffer
				+ seg_idx * xfer->seg_size;
			wa->buf_in_urb->transfer_flags
				&= ~URB_NO_TRANSFER_DMA_MAP;
		}
		wa->buf_in_urb->transfer_buffer_length =
			le32_to_cpu(xfer_result->dwTransferLength);
		wa->buf_in_urb->context = seg;
		result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);
		if (result < 0)
			goto error_submit_buf_in;
	} else {
		/* OUT data phase, complete it -- */
		seg->status = WA_SEG_DONE;
		seg->result = le32_to_cpu(xfer_result->dwTransferLength);
		xfer->segs_done++;
		rpipe_ready = rpipe_avail_inc(rpipe);
		done = __wa_xfer_is_done(xfer);
	}
	spin_unlock_irqrestore(&xfer->lock, flags);
	if (done)
		wa_xfer_completion(xfer);
	if (rpipe_ready)
		wa_xfer_delayed_run(rpipe);
	return;

error_submit_buf_in:
	if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
		dev_err(dev, "DTI: URB max acceptable errors "
			"exceeded, resetting device\n");
		wa_reset_all(wa);
	}
	if (printk_ratelimit())
		dev_err(dev, "xfer %p#%u: can't submit DTI data phase: %d\n",
			xfer, seg_idx, result);
	seg->result = result;
error_complete:
	seg->status = WA_SEG_ERROR;
	xfer->segs_done++;
	rpipe_ready = rpipe_avail_inc(rpipe);
	__wa_xfer_abort(xfer);
	done = __wa_xfer_is_done(xfer);
	spin_unlock_irqrestore(&xfer->lock, flags);
	if (done)
		wa_xfer_completion(xfer);
	if (rpipe_ready)
		wa_xfer_delayed_run(rpipe);
	return;

error_bad_seg:
	spin_unlock_irqrestore(&xfer->lock, flags);
	wa_urb_dequeue(wa, xfer->urb);
	if (printk_ratelimit())
		dev_err(dev, "xfer %p#%u: bad segment\n", xfer, seg_idx);
	if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
		dev_err(dev, "DTI: URB max acceptable errors "
			"exceeded, resetting device\n");
		wa_reset_all(wa);
	}
	return;

segment_aborted:
	/* nothing to do, as the aborter did the completion */
	spin_unlock_irqrestore(&xfer->lock, flags);
}

/*
 * Callback for the IN data phase
 *
 * If successful transition state; otherwise, take a note of the
 * error, mark this segment done and try completion.
 *
 * Note we don't access until we are sure that the transfer hasn't
 * been cancelled (ECONNRESET, ENOENT), which could mean that
 * seg->xfer could be already gone.
 */
static void wa_buf_in_cb(struct urb *urb)
{
	struct wa_seg *seg = urb->context;
	struct wa_xfer *xfer = seg->xfer;
	struct wahc *wa;
	struct device *dev;
	struct wa_rpipe *rpipe;
	unsigned rpipe_ready;
	unsigned long flags;
	u8 done = 0;

	switch (urb->status) {
	case 0:
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		rpipe = xfer->ep->hcpriv;
		dev_dbg(dev, "xfer %p#%u: data in done (%zu bytes)\n",
			xfer, seg->index, (size_t)urb->actual_length);
		seg->status = WA_SEG_DONE;
		seg->result = urb->actual_length;
		xfer->segs_done++;
		rpipe_ready = rpipe_avail_inc(rpipe);
		done = __wa_xfer_is_done(xfer);
		spin_unlock_irqrestore(&xfer->lock, flags);
		if (done)
			wa_xfer_completion(xfer);
		if (rpipe_ready)
			wa_xfer_delayed_run(rpipe);
		break;
	case -ECONNRESET:	/* URB unlinked; no need to do anything */
	case -ENOENT:		/* as it was done by the who unlinked us */
		break;
	default:		/* Other errors ... */
		spin_lock_irqsave(&xfer->lock, flags);
		wa = xfer->wa;
		dev = &wa->usb_iface->dev;
		rpipe = xfer->ep->hcpriv;
		if (printk_ratelimit())
			dev_err(dev, "xfer %p#%u: data in error %d\n",
				xfer, seg->index, urb->status);
		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
			    EDC_ERROR_TIMEFRAME)){
			dev_err(dev, "DTO: URB max acceptable errors "
				"exceeded, resetting device\n");
			wa_reset_all(wa);
		}
		seg->status = WA_SEG_ERROR;
		seg->result = urb->status;
		xfer->segs_done++;
		rpipe_ready = rpipe_avail_inc(rpipe);
		__wa_xfer_abort(xfer);
		done = __wa_xfer_is_done(xfer);
		spin_unlock_irqrestore(&xfer->lock, flags);
		if (done)
			wa_xfer_completion(xfer);
		if (rpipe_ready)
			wa_xfer_delayed_run(rpipe);
	}
}

/*
 * Handle an incoming transfer result buffer
 *
 * Given a transfer result buffer, it completes the transfer (possibly
 * scheduling and buffer in read) and then resubmits the DTI URB for a
 * new transfer result read.
 *
 *
 * The xfer_result DTI URB state machine
 *
 * States: OFF | RXR (Read-Xfer-Result) | RBI (Read-Buffer-In)
 *
 * We start in OFF mode, the first xfer_result notification [through
 * wa_handle_notif_xfer()] moves us to RXR by posting the DTI-URB to
 * read.
 *
 * We receive a buffer -- if it is not a xfer_result, we complain and
 * repost the DTI-URB. If it is a xfer_result then do the xfer seg
 * request accounting. If it is an IN segment, we move to RBI and post
 * a BUF-IN-URB to the right buffer. The BUF-IN-URB callback will
 * repost the DTI-URB and move to RXR state. if there was no IN
 * segment, it will repost the DTI-URB.
 *
 * We go back to OFF when we detect a ENOENT or ESHUTDOWN (or too many
 * errors) in the URBs.
 */
static void wa_xfer_result_cb(struct urb *urb)
{
	int result;
	struct wahc *wa = urb->context;
	struct device *dev = &wa->usb_iface->dev;
	struct wa_xfer_result *xfer_result;
	u32 xfer_id;
	struct wa_xfer *xfer;
	u8 usb_status;

	BUG_ON(wa->dti_urb != urb);
	switch (wa->dti_urb->status) {
	case 0:
		/* We have a xfer result buffer; check it */
		dev_dbg(dev, "DTI: xfer result %d bytes at %p\n",
			urb->actual_length, urb->transfer_buffer);
		if (wa->dti_urb->actual_length != sizeof(*xfer_result)) {
			dev_err(dev, "DTI Error: xfer result--bad size "
				"xfer result (%d bytes vs %zu needed)\n",
				urb->actual_length, sizeof(*xfer_result));
			break;
		}
		xfer_result = wa->xfer_result;
		if (xfer_result->hdr.bLength != sizeof(*xfer_result)) {
			dev_err(dev, "DTI Error: xfer result--"
				"bad header length %u\n",
				xfer_result->hdr.bLength);
			break;
		}
		if (xfer_result->hdr.bNotifyType != WA_XFER_RESULT) {
			dev_err(dev, "DTI Error: xfer result--"
				"bad header type 0x%02x\n",
				xfer_result->hdr.bNotifyType);
			break;
		}
		usb_status = xfer_result->bTransferStatus & 0x3f;
		if (usb_status == WA_XFER_STATUS_ABORTED
		    || usb_status == WA_XFER_STATUS_NOT_FOUND)
			/* taken care of already */
			break;
		xfer_id = xfer_result->dwTransferID;
		xfer = wa_xfer_get_by_id(wa, xfer_id);
		if (xfer == NULL) {
			/* FIXME: transaction might have been cancelled */
			dev_err(dev, "DTI Error: xfer result--"
				"unknown xfer 0x%08x (status 0x%02x)\n",
				xfer_id, usb_status);
			break;
		}
		wa_xfer_result_chew(wa, xfer);
		wa_xfer_put(xfer);
		break;
	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
	case -ESHUTDOWN:	/* going away! */
		dev_dbg(dev, "DTI: going down! %d\n", urb->status);
		goto out;
	default:
		/* Unknown error */
		if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS,
			    EDC_ERROR_TIMEFRAME)) {
			dev_err(dev, "DTI: URB max acceptable errors "
				"exceeded, resetting device\n");
			wa_reset_all(wa);
			goto out;
		}
		if (printk_ratelimit())
			dev_err(dev, "DTI: URB error %d\n", urb->status);
		break;
	}
	/* Resubmit the DTI URB */
	result = usb_submit_urb(wa->dti_urb, GFP_ATOMIC);
	if (result < 0) {
		dev_err(dev, "DTI Error: Could not submit DTI URB (%d), "
			"resetting\n", result);
		wa_reset_all(wa);
	}
out:
	return;
}

/*
 * Transfer complete notification
 *
 * Called from the notif.c code. We get a notification on EP2 saying
 * that some endpoint has some transfer result data available. We are
 * about to read it.
 *
 * To speed up things, we always have a URB reading the DTI URB; we
 * don't really set it up and start it until the first xfer complete
 * notification arrives, which is what we do here.
 *
 * Follow up in wa_xfer_result_cb(), as that's where the whole state
 * machine starts.
 *
 * So here we just initialize the DTI URB for reading transfer result
 * notifications and also the buffer-in URB, for reading buffers. Then
 * we just submit the DTI URB.
 *
 * @wa shall be referenced
 */
void wa_handle_notif_xfer(struct wahc *wa, struct wa_notif_hdr *notif_hdr)
{
	int result;
	struct device *dev = &wa->usb_iface->dev;
	struct wa_notif_xfer *notif_xfer;
	const struct usb_endpoint_descriptor *dti_epd = wa->dti_epd;

	notif_xfer = container_of(notif_hdr, struct wa_notif_xfer, hdr);
	BUG_ON(notif_hdr->bNotifyType != WA_NOTIF_TRANSFER);

	if ((0x80 | notif_xfer->bEndpoint) != dti_epd->bEndpointAddress) {
		/* FIXME: hardcoded limitation, adapt */
		dev_err(dev, "BUG: DTI ep is %u, not %u (hack me)\n",
			notif_xfer->bEndpoint, dti_epd->bEndpointAddress);
		goto error;
	}
	if (wa->dti_urb != NULL)	/* DTI URB already started */
		goto out;

	wa->dti_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (wa->dti_urb == NULL) {
		dev_err(dev, "Can't allocate DTI URB\n");
		goto error_dti_urb_alloc;
	}
	usb_fill_bulk_urb(
		wa->dti_urb, wa->usb_dev,
		usb_rcvbulkpipe(wa->usb_dev, 0x80 | notif_xfer->bEndpoint),
		wa->xfer_result, wa->xfer_result_size,
		wa_xfer_result_cb, wa);

	wa->buf_in_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (wa->buf_in_urb == NULL) {
		dev_err(dev, "Can't allocate BUF-IN URB\n");
		goto error_buf_in_urb_alloc;
	}
	usb_fill_bulk_urb(
		wa->buf_in_urb, wa->usb_dev,
		usb_rcvbulkpipe(wa->usb_dev, 0x80 | notif_xfer->bEndpoint),
		NULL, 0, wa_buf_in_cb, wa);
	result = usb_submit_urb(wa->dti_urb, GFP_KERNEL);
	if (result < 0) {
		dev_err(dev, "DTI Error: Could not submit DTI URB (%d), "
			"resetting\n", result);
		goto error_dti_urb_submit;
	}
out:
	return;

error_dti_urb_submit:
	usb_put_urb(wa->buf_in_urb);
error_buf_in_urb_alloc:
	usb_put_urb(wa->dti_urb);
	wa->dti_urb = NULL;
error_dti_urb_alloc:
error:
	wa_reset_all(wa);
}