summaryrefslogtreecommitdiffstats
path: root/drivers/scsi/ibmvscsi/ibmvscsi.c
blob: 5870866abc99e96410999261b0cdfd4cb31c710d (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
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
/* ------------------------------------------------------------
 * ibmvscsi.c
 * (C) Copyright IBM Corporation 1994, 2004
 * Authors: Colin DeVilbiss (devilbis@us.ibm.com)
 *          Santiago Leon (santil@us.ibm.com)
 *          Dave Boutcher (sleddog@us.ibm.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 * ------------------------------------------------------------
 * Emulation of a SCSI host adapter for Virtual I/O devices
 *
 * This driver supports the SCSI adapter implemented by the IBM
 * Power5 firmware.  That SCSI adapter is not a physical adapter,
 * but allows Linux SCSI peripheral drivers to directly
 * access devices in another logical partition on the physical system.
 *
 * The virtual adapter(s) are present in the open firmware device
 * tree just like real adapters.
 *
 * One of the capabilities provided on these systems is the ability
 * to DMA between partitions.  The architecture states that for VSCSI,
 * the server side is allowed to DMA to and from the client.  The client
 * is never trusted to DMA to or from the server directly.
 *
 * Messages are sent between partitions on a "Command/Response Queue" 
 * (CRQ), which is just a buffer of 16 byte entries in the receiver's 
 * Senders cannot access the buffer directly, but send messages by
 * making a hypervisor call and passing in the 16 bytes.  The hypervisor
 * puts the message in the next 16 byte space in round-robbin fashion,
 * turns on the high order bit of the message (the valid bit), and 
 * generates an interrupt to the receiver (if interrupts are turned on.) 
 * The receiver just turns off the valid bit when they have copied out
 * the message.
 *
 * The VSCSI client builds a SCSI Remote Protocol (SRP) Information Unit
 * (IU) (as defined in the T10 standard available at www.t10.org), gets 
 * a DMA address for the message, and sends it to the server as the
 * payload of a CRQ message.  The server DMAs the SRP IU and processes it,
 * including doing any additional data transfers.  When it is done, it
 * DMAs the SRP response back to the same address as the request came from,
 * and sends a CRQ message back to inform the client that the request has
 * completed.
 *
 * Note that some of the underlying infrastructure is different between
 * machines conforming to the "RS/6000 Platform Architecture" (RPA) and
 * the older iSeries hypervisor models.  To support both, some low level
 * routines have been broken out into rpa_vscsi.c and iseries_vscsi.c.
 * The Makefile should pick one, not two, not zero, of these.
 *
 * TODO: This is currently pretty tied to the IBM i/pSeries hypervisor
 * interfaces.  It would be really nice to abstract this above an RDMA
 * layer.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <asm/vio.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include "ibmvscsi.h"

/* The values below are somewhat arbitrary default values, but 
 * OS/400 will use 3 busses (disks, CDs, tapes, I think.)
 * Note that there are 3 bits of channel value, 6 bits of id, and
 * 5 bits of LUN.
 */
static int max_id = 64;
static int max_channel = 3;
static int init_timeout = 5;
static int max_requests = IBMVSCSI_MAX_REQUESTS_DEFAULT;

#define IBMVSCSI_VERSION "1.5.8"

MODULE_DESCRIPTION("IBM Virtual SCSI");
MODULE_AUTHOR("Dave Boutcher");
MODULE_LICENSE("GPL");
MODULE_VERSION(IBMVSCSI_VERSION);

module_param_named(max_id, max_id, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_id, "Largest ID value for each channel");
module_param_named(max_channel, max_channel, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_channel, "Largest channel value");
module_param_named(init_timeout, init_timeout, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds");
module_param_named(max_requests, max_requests, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_requests, "Maximum requests for this adapter");

/* ------------------------------------------------------------
 * Routines for the event pool and event structs
 */
/**
 * initialize_event_pool: - Allocates and initializes the event pool for a host
 * @pool:	event_pool to be initialized
 * @size:	Number of events in pool
 * @hostdata:	ibmvscsi_host_data who owns the event pool
 *
 * Returns zero on success.
*/
static int initialize_event_pool(struct event_pool *pool,
				 int size, struct ibmvscsi_host_data *hostdata)
{
	int i;

	pool->size = size;
	pool->next = 0;
	pool->events = kcalloc(pool->size, sizeof(*pool->events), GFP_KERNEL);
	if (!pool->events)
		return -ENOMEM;

	pool->iu_storage =
	    dma_alloc_coherent(hostdata->dev,
			       pool->size * sizeof(*pool->iu_storage),
			       &pool->iu_token, 0);
	if (!pool->iu_storage) {
		kfree(pool->events);
		return -ENOMEM;
	}

	for (i = 0; i < pool->size; ++i) {
		struct srp_event_struct *evt = &pool->events[i];
		memset(&evt->crq, 0x00, sizeof(evt->crq));
		atomic_set(&evt->free, 1);
		evt->crq.valid = 0x80;
		evt->crq.IU_length = sizeof(*evt->xfer_iu);
		evt->crq.IU_data_ptr = pool->iu_token + 
			sizeof(*evt->xfer_iu) * i;
		evt->xfer_iu = pool->iu_storage + i;
		evt->hostdata = hostdata;
		evt->ext_list = NULL;
		evt->ext_list_token = 0;
	}

	return 0;
}

/**
 * release_event_pool: - Frees memory of an event pool of a host
 * @pool:	event_pool to be released
 * @hostdata:	ibmvscsi_host_data who owns the even pool
 *
 * Returns zero on success.
*/
static void release_event_pool(struct event_pool *pool,
			       struct ibmvscsi_host_data *hostdata)
{
	int i, in_use = 0;
	for (i = 0; i < pool->size; ++i) {
		if (atomic_read(&pool->events[i].free) != 1)
			++in_use;
		if (pool->events[i].ext_list) {
			dma_free_coherent(hostdata->dev,
				  SG_ALL * sizeof(struct srp_direct_buf),
				  pool->events[i].ext_list,
				  pool->events[i].ext_list_token);
		}
	}
	if (in_use)
		dev_warn(hostdata->dev, "releasing event pool with %d "
			 "events still in use?\n", in_use);
	kfree(pool->events);
	dma_free_coherent(hostdata->dev,
			  pool->size * sizeof(*pool->iu_storage),
			  pool->iu_storage, pool->iu_token);
}

/**
 * valid_event_struct: - Determines if event is valid.
 * @pool:	event_pool that contains the event
 * @evt:	srp_event_struct to be checked for validity
 *
 * Returns zero if event is invalid, one otherwise.
*/
static int valid_event_struct(struct event_pool *pool,
				struct srp_event_struct *evt)
{
	int index = evt - pool->events;
	if (index < 0 || index >= pool->size)	/* outside of bounds */
		return 0;
	if (evt != pool->events + index)	/* unaligned */
		return 0;
	return 1;
}

/**
 * ibmvscsi_free-event_struct: - Changes status of event to "free"
 * @pool:	event_pool that contains the event
 * @evt:	srp_event_struct to be modified
 *
*/
static void free_event_struct(struct event_pool *pool,
				       struct srp_event_struct *evt)
{
	if (!valid_event_struct(pool, evt)) {
		dev_err(evt->hostdata->dev, "Freeing invalid event_struct %p "
			"(not in pool %p)\n", evt, pool->events);
		return;
	}
	if (atomic_inc_return(&evt->free) != 1) {
		dev_err(evt->hostdata->dev, "Freeing event_struct %p "
			"which is not in use!\n", evt);
		return;
	}
}

/**
 * get_evt_struct: - Gets the next free event in pool
 * @pool:	event_pool that contains the events to be searched
 *
 * Returns the next event in "free" state, and NULL if none are free.
 * Note that no synchronization is done here, we assume the host_lock
 * will syncrhonze things.
*/
static struct srp_event_struct *get_event_struct(struct event_pool *pool)
{
	int i;
	int poolsize = pool->size;
	int offset = pool->next;

	for (i = 0; i < poolsize; i++) {
		offset = (offset + 1) % poolsize;
		if (!atomic_dec_if_positive(&pool->events[offset].free)) {
			pool->next = offset;
			return &pool->events[offset];
		}
	}

	printk(KERN_ERR "ibmvscsi: found no event struct in pool!\n");
	return NULL;
}

/**
 * init_event_struct: Initialize fields in an event struct that are always 
 *                    required.
 * @evt:        The event
 * @done:       Routine to call when the event is responded to
 * @format:     SRP or MAD format
 * @timeout:    timeout value set in the CRQ
 */
static void init_event_struct(struct srp_event_struct *evt_struct,
			      void (*done) (struct srp_event_struct *),
			      u8 format,
			      int timeout)
{
	evt_struct->cmnd = NULL;
	evt_struct->cmnd_done = NULL;
	evt_struct->sync_srp = NULL;
	evt_struct->crq.format = format;
	evt_struct->crq.timeout = timeout;
	evt_struct->done = done;
}

/* ------------------------------------------------------------
 * Routines for receiving SCSI responses from the hosting partition
 */

/**
 * set_srp_direction: Set the fields in the srp related to data
 *     direction and number of buffers based on the direction in
 *     the scsi_cmnd and the number of buffers
 */
static void set_srp_direction(struct scsi_cmnd *cmd,
			      struct srp_cmd *srp_cmd, 
			      int numbuf)
{
	u8 fmt;

	if (numbuf == 0)
		return;
	
	if (numbuf == 1)
		fmt = SRP_DATA_DESC_DIRECT;
	else {
		fmt = SRP_DATA_DESC_INDIRECT;
		numbuf = min(numbuf, MAX_INDIRECT_BUFS);

		if (cmd->sc_data_direction == DMA_TO_DEVICE)
			srp_cmd->data_out_desc_cnt = numbuf;
		else
			srp_cmd->data_in_desc_cnt = numbuf;
	}

	if (cmd->sc_data_direction == DMA_TO_DEVICE)
		srp_cmd->buf_fmt = fmt << 4;
	else
		srp_cmd->buf_fmt = fmt;
}

static void unmap_sg_list(int num_entries,
		struct device *dev,
		struct srp_direct_buf *md)
{
	int i;

	for (i = 0; i < num_entries; ++i)
		dma_unmap_single(dev, md[i].va, md[i].len, DMA_BIDIRECTIONAL);
}

/**
 * unmap_cmd_data: - Unmap data pointed in srp_cmd based on the format
 * @cmd:	srp_cmd whose additional_data member will be unmapped
 * @dev:	device for which the memory is mapped
 *
*/
static void unmap_cmd_data(struct srp_cmd *cmd,
			   struct srp_event_struct *evt_struct,
			   struct device *dev)
{
	u8 out_fmt, in_fmt;

	out_fmt = cmd->buf_fmt >> 4;
	in_fmt = cmd->buf_fmt & ((1U << 4) - 1);

	if (out_fmt == SRP_NO_DATA_DESC && in_fmt == SRP_NO_DATA_DESC)
		return;
	else if (out_fmt == SRP_DATA_DESC_DIRECT ||
		 in_fmt == SRP_DATA_DESC_DIRECT) {
		struct srp_direct_buf *data =
			(struct srp_direct_buf *) cmd->add_data;
		dma_unmap_single(dev, data->va, data->len, DMA_BIDIRECTIONAL);
	} else {
		struct srp_indirect_buf *indirect =
			(struct srp_indirect_buf *) cmd->add_data;
		int num_mapped = indirect->table_desc.len /
			sizeof(struct srp_direct_buf);

		if (num_mapped <= MAX_INDIRECT_BUFS) {
			unmap_sg_list(num_mapped, dev, &indirect->desc_list[0]);
			return;
		}

		unmap_sg_list(num_mapped, dev, evt_struct->ext_list);
	}
}

static int map_sg_list(struct scsi_cmnd *cmd, int nseg,
		       struct srp_direct_buf *md)
{
	int i;
	struct scatterlist *sg;
	u64 total_length = 0;

	scsi_for_each_sg(cmd, sg, nseg, i) {
		struct srp_direct_buf *descr = md + i;
		descr->va = sg_dma_address(sg);
		descr->len = sg_dma_len(sg);
		descr->key = 0;
		total_length += sg_dma_len(sg);
 	}
	return total_length;
}

/**
 * map_sg_data: - Maps dma for a scatterlist and initializes decriptor fields
 * @cmd:	Scsi_Cmnd with the scatterlist
 * @srp_cmd:	srp_cmd that contains the memory descriptor
 * @dev:	device for which to map dma memory
 *
 * Called by map_data_for_srp_cmd() when building srp cmd from scsi cmd.
 * Returns 1 on success.
*/
static int map_sg_data(struct scsi_cmnd *cmd,
		       struct srp_event_struct *evt_struct,
		       struct srp_cmd *srp_cmd, struct device *dev)
{

	int sg_mapped;
	u64 total_length = 0;
	struct srp_direct_buf *data =
		(struct srp_direct_buf *) srp_cmd->add_data;
	struct srp_indirect_buf *indirect =
		(struct srp_indirect_buf *) data;

	sg_mapped = scsi_dma_map(cmd);
	if (!sg_mapped)
		return 1;
	else if (sg_mapped < 0)
		return 0;
	else if (sg_mapped > SG_ALL) {
		printk(KERN_ERR
		       "ibmvscsi: More than %d mapped sg entries, got %d\n",
		       SG_ALL, sg_mapped);
		return 0;
	}

	set_srp_direction(cmd, srp_cmd, sg_mapped);

	/* special case; we can use a single direct descriptor */
	if (sg_mapped == 1) {
		map_sg_list(cmd, sg_mapped, data);
		return 1;
	}

	indirect->table_desc.va = 0;
	indirect->table_desc.len = sg_mapped * sizeof(struct srp_direct_buf);
	indirect->table_desc.key = 0;

	if (sg_mapped <= MAX_INDIRECT_BUFS) {
		total_length = map_sg_list(cmd, sg_mapped,
					   &indirect->desc_list[0]);
		indirect->len = total_length;
		return 1;
	}

	/* get indirect table */
	if (!evt_struct->ext_list) {
		evt_struct->ext_list = (struct srp_direct_buf *)
			dma_alloc_coherent(dev,
					   SG_ALL * sizeof(struct srp_direct_buf),
					   &evt_struct->ext_list_token, 0);
		if (!evt_struct->ext_list) {
			sdev_printk(KERN_ERR, cmd->device,
				    "Can't allocate memory for indirect table\n");
			return 0;
		}
	}

	total_length = map_sg_list(cmd, sg_mapped, evt_struct->ext_list);

	indirect->len = total_length;
	indirect->table_desc.va = evt_struct->ext_list_token;
	indirect->table_desc.len = sg_mapped * sizeof(indirect->desc_list[0]);
	memcpy(indirect->desc_list, evt_struct->ext_list,
	       MAX_INDIRECT_BUFS * sizeof(struct srp_direct_buf));
 	return 1;
}

/**
 * map_data_for_srp_cmd: - Calls functions to map data for srp cmds
 * @cmd:	struct scsi_cmnd with the memory to be mapped
 * @srp_cmd:	srp_cmd that contains the memory descriptor
 * @dev:	dma device for which to map dma memory
 *
 * Called by scsi_cmd_to_srp_cmd() when converting scsi cmds to srp cmds 
 * Returns 1 on success.
*/
static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
				struct srp_event_struct *evt_struct,
				struct srp_cmd *srp_cmd, struct device *dev)
{
	switch (cmd->sc_data_direction) {
	case DMA_FROM_DEVICE:
	case DMA_TO_DEVICE:
		break;
	case DMA_NONE:
		return 1;
	case DMA_BIDIRECTIONAL:
		sdev_printk(KERN_ERR, cmd->device,
			    "Can't map DMA_BIDIRECTIONAL to read/write\n");
		return 0;
	default:
		sdev_printk(KERN_ERR, cmd->device,
			    "Unknown data direction 0x%02x; can't map!\n",
			    cmd->sc_data_direction);
		return 0;
	}

	return map_sg_data(cmd, evt_struct, srp_cmd, dev);
}

/**
 * purge_requests: Our virtual adapter just shut down.  purge any sent requests
 * @hostdata:    the adapter
 */
static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
{
	struct srp_event_struct *tmp_evt, *pos;
	unsigned long flags;

	spin_lock_irqsave(hostdata->host->host_lock, flags);
	list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
		list_del(&tmp_evt->list);
		del_timer(&tmp_evt->timer);
		if (tmp_evt->cmnd) {
			tmp_evt->cmnd->result = (error_code << 16);
			unmap_cmd_data(&tmp_evt->iu.srp.cmd,
				       tmp_evt,
				       tmp_evt->hostdata->dev);
			if (tmp_evt->cmnd_done)
				tmp_evt->cmnd_done(tmp_evt->cmnd);
		} else if (tmp_evt->done)
			tmp_evt->done(tmp_evt);
		free_event_struct(&tmp_evt->hostdata->pool, tmp_evt);
	}
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
}

/**
 * ibmvscsi_reset_host - Reset the connection to the server
 * @hostdata:	struct ibmvscsi_host_data to reset
*/
static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
{
	scsi_block_requests(hostdata->host);
	atomic_set(&hostdata->request_limit, 0);

	purge_requests(hostdata, DID_ERROR);
	if ((ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata)) ||
	    (ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0)) ||
	    (vio_enable_interrupts(to_vio_dev(hostdata->dev)))) {
		atomic_set(&hostdata->request_limit, -1);
		dev_err(hostdata->dev, "error after reset\n");
	}

	scsi_unblock_requests(hostdata->host);
}

/**
 * ibmvscsi_timeout - Internal command timeout handler
 * @evt_struct:	struct srp_event_struct that timed out
 *
 * Called when an internally generated command times out
*/
static void ibmvscsi_timeout(struct srp_event_struct *evt_struct)
{
	struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;

	dev_err(hostdata->dev, "Command timed out (%x). Resetting connection\n",
		evt_struct->iu.srp.cmd.opcode);

	ibmvscsi_reset_host(hostdata);
}


/* ------------------------------------------------------------
 * Routines for sending and receiving SRPs
 */
/**
 * ibmvscsi_send_srp_event: - Transforms event to u64 array and calls send_crq()
 * @evt_struct:	evt_struct to be sent
 * @hostdata:	ibmvscsi_host_data of host
 * @timeout:	timeout in seconds - 0 means do not time command
 *
 * Returns the value returned from ibmvscsi_send_crq(). (Zero for success)
 * Note that this routine assumes that host_lock is held for synchronization
*/
static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
				   struct ibmvscsi_host_data *hostdata,
				   unsigned long timeout)
{
	u64 *crq_as_u64 = (u64 *) &evt_struct->crq;
	int request_status;
	int rc;

	/* If we have exhausted our request limit, just fail this request,
	 * unless it is for a reset or abort.
	 * Note that there are rare cases involving driver generated requests 
	 * (such as task management requests) that the mid layer may think we
	 * can handle more requests (can_queue) when we actually can't
	 */
	if (evt_struct->crq.format == VIOSRP_SRP_FORMAT) {
		request_status =
			atomic_dec_if_positive(&hostdata->request_limit);
		/* If request limit was -1 when we started, it is now even
		 * less than that
		 */
		if (request_status < -1)
			goto send_error;
		/* Otherwise, we may have run out of requests. */
		/* Abort and reset calls should make it through.
		 * Nothing except abort and reset should use the last two
		 * slots unless we had two or less to begin with.
		 */
		else if (request_status < 2 &&
		         evt_struct->iu.srp.cmd.opcode != SRP_TSK_MGMT) {
			/* In the case that we have less than two requests
			 * available, check the server limit as a combination
			 * of the request limit and the number of requests
			 * in-flight (the size of the send list).  If the
			 * server limit is greater than 2, return busy so
			 * that the last two are reserved for reset and abort.
			 */
			int server_limit = request_status;
			struct srp_event_struct *tmp_evt;

			list_for_each_entry(tmp_evt, &hostdata->sent, list) {
				server_limit++;
			}

			if (server_limit > 2)
				goto send_busy;
		}
	}

	/* Copy the IU into the transfer area */
	*evt_struct->xfer_iu = evt_struct->iu;
	evt_struct->xfer_iu->srp.rsp.tag = (u64)evt_struct;

	/* Add this to the sent list.  We need to do this 
	 * before we actually send 
	 * in case it comes back REALLY fast
	 */
	list_add_tail(&evt_struct->list, &hostdata->sent);

	init_timer(&evt_struct->timer);
	if (timeout) {
		evt_struct->timer.data = (unsigned long) evt_struct;
		evt_struct->timer.expires = jiffies + (timeout * HZ);
		evt_struct->timer.function = (void (*)(unsigned long))ibmvscsi_timeout;
		add_timer(&evt_struct->timer);
	}

	if ((rc =
	     ibmvscsi_send_crq(hostdata, crq_as_u64[0], crq_as_u64[1])) != 0) {
		list_del(&evt_struct->list);
		del_timer(&evt_struct->timer);

		dev_err(hostdata->dev, "send error %d\n", rc);
		atomic_inc(&hostdata->request_limit);
		goto send_error;
	}

	return 0;

 send_busy:
	unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);

	free_event_struct(&hostdata->pool, evt_struct);
	atomic_inc(&hostdata->request_limit);
	return SCSI_MLQUEUE_HOST_BUSY;

 send_error:
	unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);

	if (evt_struct->cmnd != NULL) {
		evt_struct->cmnd->result = DID_ERROR << 16;
		evt_struct->cmnd_done(evt_struct->cmnd);
	} else if (evt_struct->done)
		evt_struct->done(evt_struct);

	free_event_struct(&hostdata->pool, evt_struct);
	return 0;
}

/**
 * handle_cmd_rsp: -  Handle responses from commands
 * @evt_struct:	srp_event_struct to be handled
 *
 * Used as a callback by when sending scsi cmds.
 * Gets called by ibmvscsi_handle_crq()
*/
static void handle_cmd_rsp(struct srp_event_struct *evt_struct)
{
	struct srp_rsp *rsp = &evt_struct->xfer_iu->srp.rsp;
	struct scsi_cmnd *cmnd = evt_struct->cmnd;

	if (unlikely(rsp->opcode != SRP_RSP)) {
		if (printk_ratelimit())
			dev_warn(evt_struct->hostdata->dev,
				 "bad SRP RSP type %d\n", rsp->opcode);
	}
	
	if (cmnd) {
		cmnd->result = rsp->status;
		if (((cmnd->result >> 1) & 0x1f) == CHECK_CONDITION)
			memcpy(cmnd->sense_buffer,
			       rsp->data,
			       rsp->sense_data_len);
		unmap_cmd_data(&evt_struct->iu.srp.cmd, 
			       evt_struct, 
			       evt_struct->hostdata->dev);

		if (rsp->flags & SRP_RSP_FLAG_DOOVER)
			scsi_set_resid(cmnd, rsp->data_out_res_cnt);
		else if (rsp->flags & SRP_RSP_FLAG_DIOVER)
			scsi_set_resid(cmnd, rsp->data_in_res_cnt);
	}

	if (evt_struct->cmnd_done)
		evt_struct->cmnd_done(cmnd);
}

/**
 * lun_from_dev: - Returns the lun of the scsi device
 * @dev:	struct scsi_device
 *
*/
static inline u16 lun_from_dev(struct scsi_device *dev)
{
	return (0x2 << 14) | (dev->id << 8) | (dev->channel << 5) | dev->lun;
}

/**
 * ibmvscsi_queue: - The queuecommand function of the scsi template 
 * @cmd:	struct scsi_cmnd to be executed
 * @done:	Callback function to be called when cmd is completed
*/
static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
				 void (*done) (struct scsi_cmnd *))
{
	struct srp_cmd *srp_cmd;
	struct srp_event_struct *evt_struct;
	struct srp_indirect_buf *indirect;
	struct ibmvscsi_host_data *hostdata =
		(struct ibmvscsi_host_data *)&cmnd->device->host->hostdata;
	u16 lun = lun_from_dev(cmnd->device);
	u8 out_fmt, in_fmt;

	evt_struct = get_event_struct(&hostdata->pool);
	if (!evt_struct)
		return SCSI_MLQUEUE_HOST_BUSY;

	/* Set up the actual SRP IU */
	srp_cmd = &evt_struct->iu.srp.cmd;
	memset(srp_cmd, 0x00, SRP_MAX_IU_LEN);
	srp_cmd->opcode = SRP_CMD;
	memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(cmnd->cmnd));
	srp_cmd->lun = ((u64) lun) << 48;

	if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
		sdev_printk(KERN_ERR, cmnd->device, "couldn't convert cmd to srp_cmd\n");
		free_event_struct(&hostdata->pool, evt_struct);
		return SCSI_MLQUEUE_HOST_BUSY;
	}

	init_event_struct(evt_struct,
			  handle_cmd_rsp,
			  VIOSRP_SRP_FORMAT,
			  cmnd->timeout_per_command/HZ);

	evt_struct->cmnd = cmnd;
	evt_struct->cmnd_done = done;

	/* Fix up dma address of the buffer itself */
	indirect = (struct srp_indirect_buf *) srp_cmd->add_data;
	out_fmt = srp_cmd->buf_fmt >> 4;
	in_fmt = srp_cmd->buf_fmt & ((1U << 4) - 1);
	if ((in_fmt == SRP_DATA_DESC_INDIRECT ||
	     out_fmt == SRP_DATA_DESC_INDIRECT) &&
	    indirect->table_desc.va == 0) {
		indirect->table_desc.va = evt_struct->crq.IU_data_ptr +
			offsetof(struct srp_cmd, add_data) +
			offsetof(struct srp_indirect_buf, desc_list);
	}

	return ibmvscsi_send_srp_event(evt_struct, hostdata, 0);
}

/* ------------------------------------------------------------
 * Routines for driver initialization
 */
/**
 * adapter_info_rsp: - Handle response to MAD adapter info request
 * @evt_struct:	srp_event_struct with the response
 *
 * Used as a "done" callback by when sending adapter_info. Gets called
 * by ibmvscsi_handle_crq()
*/
static void adapter_info_rsp(struct srp_event_struct *evt_struct)
{
	struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
	dma_unmap_single(hostdata->dev,
			 evt_struct->iu.mad.adapter_info.buffer,
			 evt_struct->iu.mad.adapter_info.common.length,
			 DMA_BIDIRECTIONAL);

	if (evt_struct->xfer_iu->mad.adapter_info.common.status) {
		dev_err(hostdata->dev, "error %d getting adapter info\n",
			evt_struct->xfer_iu->mad.adapter_info.common.status);
	} else {
		dev_info(hostdata->dev, "host srp version: %s, "
			 "host partition %s (%d), OS %d, max io %u\n",
			 hostdata->madapter_info.srp_version,
			 hostdata->madapter_info.partition_name,
			 hostdata->madapter_info.partition_number,
			 hostdata->madapter_info.os_type,
			 hostdata->madapter_info.port_max_txu[0]);
		
		if (hostdata->madapter_info.port_max_txu[0]) 
			hostdata->host->max_sectors = 
				hostdata->madapter_info.port_max_txu[0] >> 9;
		
		if (hostdata->madapter_info.os_type == 3 &&
		    strcmp(hostdata->madapter_info.srp_version, "1.6a") <= 0) {
			dev_err(hostdata->dev, "host (Ver. %s) doesn't support large transfers\n",
				hostdata->madapter_info.srp_version);
			dev_err(hostdata->dev, "limiting scatterlists to %d\n",
				MAX_INDIRECT_BUFS);
			hostdata->host->sg_tablesize = MAX_INDIRECT_BUFS;
		}
	}
}

/**
 * send_mad_adapter_info: - Sends the mad adapter info request
 *      and stores the result so it can be retrieved with
 *      sysfs.  We COULD consider causing a failure if the
 *      returned SRP version doesn't match ours.
 * @hostdata:	ibmvscsi_host_data of host
 * 
 * Returns zero if successful.
*/
static void send_mad_adapter_info(struct ibmvscsi_host_data *hostdata)
{
	struct viosrp_adapter_info *req;
	struct srp_event_struct *evt_struct;
	unsigned long flags;
	dma_addr_t addr;

	evt_struct = get_event_struct(&hostdata->pool);
	if (!evt_struct) {
		dev_err(hostdata->dev,
			"couldn't allocate an event for ADAPTER_INFO_REQ!\n");
		return;
	}

	init_event_struct(evt_struct,
			  adapter_info_rsp,
			  VIOSRP_MAD_FORMAT,
			  init_timeout);
	
	req = &evt_struct->iu.mad.adapter_info;
	memset(req, 0x00, sizeof(*req));
	
	req->common.type = VIOSRP_ADAPTER_INFO_TYPE;
	req->common.length = sizeof(hostdata->madapter_info);
	req->buffer = addr = dma_map_single(hostdata->dev,
					    &hostdata->madapter_info,
					    sizeof(hostdata->madapter_info),
					    DMA_BIDIRECTIONAL);

	if (dma_mapping_error(req->buffer)) {
		dev_err(hostdata->dev, "Unable to map request_buffer for adapter_info!\n");
		free_event_struct(&hostdata->pool, evt_struct);
		return;
	}
	
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	if (ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2)) {
		dev_err(hostdata->dev, "couldn't send ADAPTER_INFO_REQ!\n");
		dma_unmap_single(hostdata->dev,
				 addr,
				 sizeof(hostdata->madapter_info),
				 DMA_BIDIRECTIONAL);
	}
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
};

/**
 * login_rsp: - Handle response to SRP login request
 * @evt_struct:	srp_event_struct with the response
 *
 * Used as a "done" callback by when sending srp_login. Gets called
 * by ibmvscsi_handle_crq()
*/
static void login_rsp(struct srp_event_struct *evt_struct)
{
	struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
	switch (evt_struct->xfer_iu->srp.login_rsp.opcode) {
	case SRP_LOGIN_RSP:	/* it worked! */
		break;
	case SRP_LOGIN_REJ:	/* refused! */
		dev_info(hostdata->dev, "SRP_LOGIN_REJ reason %u\n",
			 evt_struct->xfer_iu->srp.login_rej.reason);
		/* Login failed.  */
		atomic_set(&hostdata->request_limit, -1);
		return;
	default:
		dev_err(hostdata->dev, "Invalid login response typecode 0x%02x!\n",
			evt_struct->xfer_iu->srp.login_rsp.opcode);
		/* Login failed.  */
		atomic_set(&hostdata->request_limit, -1);
		return;
	}

	dev_info(hostdata->dev, "SRP_LOGIN succeeded\n");

	if (evt_struct->xfer_iu->srp.login_rsp.req_lim_delta < 0)
		dev_err(hostdata->dev, "Invalid request_limit.\n");

	/* Now we know what the real request-limit is.
	 * This value is set rather than added to request_limit because
	 * request_limit could have been set to -1 by this client.
	 */
	atomic_set(&hostdata->request_limit,
		   evt_struct->xfer_iu->srp.login_rsp.req_lim_delta);

	/* If we had any pending I/Os, kick them */
	scsi_unblock_requests(hostdata->host);

	send_mad_adapter_info(hostdata);
	return;
}

/**
 * send_srp_login: - Sends the srp login
 * @hostdata:	ibmvscsi_host_data of host
 * 
 * Returns zero if successful.
*/
static int send_srp_login(struct ibmvscsi_host_data *hostdata)
{
	int rc;
	unsigned long flags;
	struct srp_login_req *login;
	struct srp_event_struct *evt_struct = get_event_struct(&hostdata->pool);
	if (!evt_struct) {
		dev_err(hostdata->dev, "couldn't allocate an event for login req!\n");
		return FAILED;
	}

	init_event_struct(evt_struct,
			  login_rsp,
			  VIOSRP_SRP_FORMAT,
			  init_timeout);

	login = &evt_struct->iu.srp.login_req;
	memset(login, 0x00, sizeof(struct srp_login_req));
	login->opcode = SRP_LOGIN_REQ;
	login->req_it_iu_len = sizeof(union srp_iu);
	login->req_buf_fmt = SRP_BUF_FORMAT_DIRECT | SRP_BUF_FORMAT_INDIRECT;
	
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	/* Start out with a request limit of 1, since this is negotiated in
	 * the login request we are just sending
	 */
	atomic_set(&hostdata->request_limit, 1);

	rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	dev_info(hostdata->dev, "sent SRP login\n");
	return rc;
};

/**
 * sync_completion: Signal that a synchronous command has completed
 * Note that after returning from this call, the evt_struct is freed.
 * the caller waiting on this completion shouldn't touch the evt_struct
 * again.
 */
static void sync_completion(struct srp_event_struct *evt_struct)
{
	/* copy the response back */
	if (evt_struct->sync_srp)
		*evt_struct->sync_srp = *evt_struct->xfer_iu;
	
	complete(&evt_struct->comp);
}

/**
 * ibmvscsi_abort: Abort a command...from scsi host template
 * send this over to the server and wait synchronously for the response
 */
static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)
{
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)cmd->device->host->hostdata;
	struct srp_tsk_mgmt *tsk_mgmt;
	struct srp_event_struct *evt;
	struct srp_event_struct *tmp_evt, *found_evt;
	union viosrp_iu srp_rsp;
	int rsp_rc;
	unsigned long flags;
	u16 lun = lun_from_dev(cmd->device);

	/* First, find this command in our sent list so we can figure
	 * out the correct tag
	 */
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	found_evt = NULL;
	list_for_each_entry(tmp_evt, &hostdata->sent, list) {
		if (tmp_evt->cmnd == cmd) {
			found_evt = tmp_evt;
			break;
		}
	}

	if (!found_evt) {
		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
		return SUCCESS;
	}

	evt = get_event_struct(&hostdata->pool);
	if (evt == NULL) {
		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
		sdev_printk(KERN_ERR, cmd->device, "failed to allocate abort event\n");
		return FAILED;
	}
	
	init_event_struct(evt,
			  sync_completion,
			  VIOSRP_SRP_FORMAT,
			  init_timeout);

	tsk_mgmt = &evt->iu.srp.tsk_mgmt;
	
	/* Set up an abort SRP command */
	memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
	tsk_mgmt->opcode = SRP_TSK_MGMT;
	tsk_mgmt->lun = ((u64) lun) << 48;
	tsk_mgmt->tsk_mgmt_func = SRP_TSK_ABORT_TASK;
	tsk_mgmt->task_tag = (u64) found_evt;

	sdev_printk(KERN_INFO, cmd->device, "aborting command. lun 0x%lx, tag 0x%lx\n",
		    tsk_mgmt->lun, tsk_mgmt->task_tag);

	evt->sync_srp = &srp_rsp;
	init_completion(&evt->comp);
	rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	if (rsp_rc != 0) {
		sdev_printk(KERN_ERR, cmd->device,
			    "failed to send abort() event. rc=%d\n", rsp_rc);
		return FAILED;
	}

	wait_for_completion(&evt->comp);

	/* make sure we got a good response */
	if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
		if (printk_ratelimit())
			sdev_printk(KERN_WARNING, cmd->device, "abort bad SRP RSP type %d\n",
				    srp_rsp.srp.rsp.opcode);
		return FAILED;
	}

	if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
		rsp_rc = *((int *)srp_rsp.srp.rsp.data);
	else
		rsp_rc = srp_rsp.srp.rsp.status;

	if (rsp_rc) {
		if (printk_ratelimit())
			sdev_printk(KERN_WARNING, cmd->device,
				    "abort code %d for task tag 0x%lx\n",
				    rsp_rc, tsk_mgmt->task_tag);
		return FAILED;
	}

	/* Because we dropped the spinlock above, it's possible
	 * The event is no longer in our list.  Make sure it didn't
	 * complete while we were aborting
	 */
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	found_evt = NULL;
	list_for_each_entry(tmp_evt, &hostdata->sent, list) {
		if (tmp_evt->cmnd == cmd) {
			found_evt = tmp_evt;
			break;
		}
	}

	if (found_evt == NULL) {
		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
		sdev_printk(KERN_INFO, cmd->device, "aborted task tag 0x%lx completed\n",
			    tsk_mgmt->task_tag);
		return SUCCESS;
	}

	sdev_printk(KERN_INFO, cmd->device, "successfully aborted task tag 0x%lx\n",
		    tsk_mgmt->task_tag);

	cmd->result = (DID_ABORT << 16);
	list_del(&found_evt->list);
	unmap_cmd_data(&found_evt->iu.srp.cmd, found_evt,
		       found_evt->hostdata->dev);
	free_event_struct(&found_evt->hostdata->pool, found_evt);
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	atomic_inc(&hostdata->request_limit);
	return SUCCESS;
}

/**
 * ibmvscsi_eh_device_reset_handler: Reset a single LUN...from scsi host 
 * template send this over to the server and wait synchronously for the 
 * response
 */
static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)cmd->device->host->hostdata;

	struct srp_tsk_mgmt *tsk_mgmt;
	struct srp_event_struct *evt;
	struct srp_event_struct *tmp_evt, *pos;
	union viosrp_iu srp_rsp;
	int rsp_rc;
	unsigned long flags;
	u16 lun = lun_from_dev(cmd->device);

	spin_lock_irqsave(hostdata->host->host_lock, flags);
	evt = get_event_struct(&hostdata->pool);
	if (evt == NULL) {
		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
		sdev_printk(KERN_ERR, cmd->device, "failed to allocate reset event\n");
		return FAILED;
	}
	
	init_event_struct(evt,
			  sync_completion,
			  VIOSRP_SRP_FORMAT,
			  init_timeout);

	tsk_mgmt = &evt->iu.srp.tsk_mgmt;

	/* Set up a lun reset SRP command */
	memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
	tsk_mgmt->opcode = SRP_TSK_MGMT;
	tsk_mgmt->lun = ((u64) lun) << 48;
	tsk_mgmt->tsk_mgmt_func = SRP_TSK_LUN_RESET;

	sdev_printk(KERN_INFO, cmd->device, "resetting device. lun 0x%lx\n",
		    tsk_mgmt->lun);

	evt->sync_srp = &srp_rsp;
	init_completion(&evt->comp);
	rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	if (rsp_rc != 0) {
		sdev_printk(KERN_ERR, cmd->device,
			    "failed to send reset event. rc=%d\n", rsp_rc);
		return FAILED;
	}

	wait_for_completion(&evt->comp);

	/* make sure we got a good response */
	if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
		if (printk_ratelimit())
			sdev_printk(KERN_WARNING, cmd->device, "reset bad SRP RSP type %d\n",
				    srp_rsp.srp.rsp.opcode);
		return FAILED;
	}

	if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
		rsp_rc = *((int *)srp_rsp.srp.rsp.data);
	else
		rsp_rc = srp_rsp.srp.rsp.status;

	if (rsp_rc) {
		if (printk_ratelimit())
			sdev_printk(KERN_WARNING, cmd->device,
				    "reset code %d for task tag 0x%lx\n",
				    rsp_rc, tsk_mgmt->task_tag);
		return FAILED;
	}

	/* We need to find all commands for this LUN that have not yet been
	 * responded to, and fail them with DID_RESET
	 */
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
		if ((tmp_evt->cmnd) && (tmp_evt->cmnd->device == cmd->device)) {
			if (tmp_evt->cmnd)
				tmp_evt->cmnd->result = (DID_RESET << 16);
			list_del(&tmp_evt->list);
			unmap_cmd_data(&tmp_evt->iu.srp.cmd, tmp_evt,
				       tmp_evt->hostdata->dev);
			free_event_struct(&tmp_evt->hostdata->pool,
						   tmp_evt);
			atomic_inc(&hostdata->request_limit);
			if (tmp_evt->cmnd_done)
				tmp_evt->cmnd_done(tmp_evt->cmnd);
			else if (tmp_evt->done)
				tmp_evt->done(tmp_evt);
		}
	}
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	return SUCCESS;
}

/**
 * ibmvscsi_eh_host_reset_handler - Reset the connection to the server
 * @cmd:	struct scsi_cmnd having problems
*/
static int ibmvscsi_eh_host_reset_handler(struct scsi_cmnd *cmd)
{
	unsigned long wait_switch = 0;
	struct ibmvscsi_host_data *hostdata =
		(struct ibmvscsi_host_data *)cmd->device->host->hostdata;

	dev_err(hostdata->dev, "Resetting connection due to error recovery\n");

	ibmvscsi_reset_host(hostdata);

	for (wait_switch = jiffies + (init_timeout * HZ);
	     time_before(jiffies, wait_switch) &&
		     atomic_read(&hostdata->request_limit) < 2;) {

		msleep(10);
	}

	if (atomic_read(&hostdata->request_limit) <= 0)
		return FAILED;

	return SUCCESS;
}

/**
 * ibmvscsi_handle_crq: - Handles and frees received events in the CRQ
 * @crq:	Command/Response queue
 * @hostdata:	ibmvscsi_host_data of host
 *
*/
void ibmvscsi_handle_crq(struct viosrp_crq *crq,
			 struct ibmvscsi_host_data *hostdata)
{
	long rc;
	unsigned long flags;
	struct srp_event_struct *evt_struct =
	    (struct srp_event_struct *)crq->IU_data_ptr;
	switch (crq->valid) {
	case 0xC0:		/* initialization */
		switch (crq->format) {
		case 0x01:	/* Initialization message */
			dev_info(hostdata->dev, "partner initialized\n");
			/* Send back a response */
			if ((rc = ibmvscsi_send_crq(hostdata,
						    0xC002000000000000LL, 0)) == 0) {
				/* Now login */
				send_srp_login(hostdata);
			} else {
				dev_err(hostdata->dev, "Unable to send init rsp. rc=%ld\n", rc);
			}

			break;
		case 0x02:	/* Initialization response */
			dev_info(hostdata->dev, "partner initialization complete\n");

			/* Now login */
			send_srp_login(hostdata);
			break;
		default:
			dev_err(hostdata->dev, "unknown crq message type: %d\n", crq->format);
		}
		return;
	case 0xFF:	/* Hypervisor telling us the connection is closed */
		scsi_block_requests(hostdata->host);
		atomic_set(&hostdata->request_limit, 0);
		if (crq->format == 0x06) {
			/* We need to re-setup the interpartition connection */
			dev_info(hostdata->dev, "Re-enabling adapter!\n");
			purge_requests(hostdata, DID_REQUEUE);
			if ((ibmvscsi_reenable_crq_queue(&hostdata->queue,
							hostdata)) ||
			    (ibmvscsi_send_crq(hostdata,
					       0xC001000000000000LL, 0))) {
					atomic_set(&hostdata->request_limit,
						   -1);
					dev_err(hostdata->dev, "error after enable\n");
			}
		} else {
			dev_err(hostdata->dev, "Virtual adapter failed rc %d!\n",
				crq->format);

			purge_requests(hostdata, DID_ERROR);
			if ((ibmvscsi_reset_crq_queue(&hostdata->queue,
							hostdata)) ||
			    (ibmvscsi_send_crq(hostdata,
					       0xC001000000000000LL, 0))) {
					atomic_set(&hostdata->request_limit,
						   -1);
					dev_err(hostdata->dev, "error after reset\n");
			}
		}
		scsi_unblock_requests(hostdata->host);
		return;
	case 0x80:		/* real payload */
		break;
	default:
		dev_err(hostdata->dev, "got an invalid message type 0x%02x\n",
			crq->valid);
		return;
	}

	/* The only kind of payload CRQs we should get are responses to
	 * things we send. Make sure this response is to something we
	 * actually sent
	 */
	if (!valid_event_struct(&hostdata->pool, evt_struct)) {
		dev_err(hostdata->dev, "returned correlation_token 0x%p is invalid!\n",
		       (void *)crq->IU_data_ptr);
		return;
	}

	if (atomic_read(&evt_struct->free)) {
		dev_err(hostdata->dev, "received duplicate correlation_token 0x%p!\n",
			(void *)crq->IU_data_ptr);
		return;
	}

	if (crq->format == VIOSRP_SRP_FORMAT)
		atomic_add(evt_struct->xfer_iu->srp.rsp.req_lim_delta,
			   &hostdata->request_limit);

	del_timer(&evt_struct->timer);

	if (evt_struct->done)
		evt_struct->done(evt_struct);
	else
		dev_err(hostdata->dev, "returned done() is NULL; not running it!\n");

	/*
	 * Lock the host_lock before messing with these structures, since we
	 * are running in a task context
	 */
	spin_lock_irqsave(evt_struct->hostdata->host->host_lock, flags);
	list_del(&evt_struct->list);
	free_event_struct(&evt_struct->hostdata->pool, evt_struct);
	spin_unlock_irqrestore(evt_struct->hostdata->host->host_lock, flags);
}

/**
 * ibmvscsi_get_host_config: Send the command to the server to get host
 * configuration data.  The data is opaque to us.
 */
static int ibmvscsi_do_host_config(struct ibmvscsi_host_data *hostdata,
				   unsigned char *buffer, int length)
{
	struct viosrp_host_config *host_config;
	struct srp_event_struct *evt_struct;
	unsigned long flags;
	dma_addr_t addr;
	int rc;

	evt_struct = get_event_struct(&hostdata->pool);
	if (!evt_struct) {
		dev_err(hostdata->dev, "couldn't allocate event for HOST_CONFIG!\n");
		return -1;
	}

	init_event_struct(evt_struct,
			  sync_completion,
			  VIOSRP_MAD_FORMAT,
			  init_timeout);

	host_config = &evt_struct->iu.mad.host_config;

	/* Set up a lun reset SRP command */
	memset(host_config, 0x00, sizeof(*host_config));
	host_config->common.type = VIOSRP_HOST_CONFIG_TYPE;
	host_config->common.length = length;
	host_config->buffer = addr = dma_map_single(hostdata->dev, buffer,
						    length,
						    DMA_BIDIRECTIONAL);

	if (dma_mapping_error(host_config->buffer)) {
		dev_err(hostdata->dev, "dma_mapping error getting host config\n");
		free_event_struct(&hostdata->pool, evt_struct);
		return -1;
	}

	init_completion(&evt_struct->comp);
	spin_lock_irqsave(hostdata->host->host_lock, flags);
	rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
	spin_unlock_irqrestore(hostdata->host->host_lock, flags);
	if (rc == 0)
		wait_for_completion(&evt_struct->comp);
	dma_unmap_single(hostdata->dev, addr, length, DMA_BIDIRECTIONAL);

	return rc;
}

/**
 * ibmvscsi_slave_configure: Set the "allow_restart" flag for each disk.
 * @sdev:	struct scsi_device device to configure
 *
 * Enable allow_restart for a device if it is a disk.  Adjust the
 * queue_depth here also as is required by the documentation for
 * struct scsi_host_template.
 */
static int ibmvscsi_slave_configure(struct scsi_device *sdev)
{
	struct Scsi_Host *shost = sdev->host;
	unsigned long lock_flags = 0;

	spin_lock_irqsave(shost->host_lock, lock_flags);
	if (sdev->type == TYPE_DISK)
		sdev->allow_restart = 1;
	scsi_adjust_queue_depth(sdev, 0, shost->cmd_per_lun);
	spin_unlock_irqrestore(shost->host_lock, lock_flags);
	return 0;
}

/**
 * ibmvscsi_change_queue_depth - Change the device's queue depth
 * @sdev:	scsi device struct
 * @qdepth:	depth to set
 *
 * Return value:
 * 	actual depth set
 **/
static int ibmvscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
{
	if (qdepth > IBMVSCSI_MAX_CMDS_PER_LUN)
		qdepth = IBMVSCSI_MAX_CMDS_PER_LUN;

	scsi_adjust_queue_depth(sdev, 0, qdepth);
	return sdev->queue_depth;
}

/* ------------------------------------------------------------
 * sysfs attributes
 */
static ssize_t show_host_srp_version(struct class_device *class_dev, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;
	int len;

	len = snprintf(buf, PAGE_SIZE, "%s\n",
		       hostdata->madapter_info.srp_version);
	return len;
}

static struct class_device_attribute ibmvscsi_host_srp_version = {
	.attr = {
		 .name = "srp_version",
		 .mode = S_IRUGO,
		 },
	.show = show_host_srp_version,
};

static ssize_t show_host_partition_name(struct class_device *class_dev,
					char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;
	int len;

	len = snprintf(buf, PAGE_SIZE, "%s\n",
		       hostdata->madapter_info.partition_name);
	return len;
}

static struct class_device_attribute ibmvscsi_host_partition_name = {
	.attr = {
		 .name = "partition_name",
		 .mode = S_IRUGO,
		 },
	.show = show_host_partition_name,
};

static ssize_t show_host_partition_number(struct class_device *class_dev,
					  char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;
	int len;

	len = snprintf(buf, PAGE_SIZE, "%d\n",
		       hostdata->madapter_info.partition_number);
	return len;
}

static struct class_device_attribute ibmvscsi_host_partition_number = {
	.attr = {
		 .name = "partition_number",
		 .mode = S_IRUGO,
		 },
	.show = show_host_partition_number,
};

static ssize_t show_host_mad_version(struct class_device *class_dev, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;
	int len;

	len = snprintf(buf, PAGE_SIZE, "%d\n",
		       hostdata->madapter_info.mad_version);
	return len;
}

static struct class_device_attribute ibmvscsi_host_mad_version = {
	.attr = {
		 .name = "mad_version",
		 .mode = S_IRUGO,
		 },
	.show = show_host_mad_version,
};

static ssize_t show_host_os_type(struct class_device *class_dev, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;
	int len;

	len = snprintf(buf, PAGE_SIZE, "%d\n", hostdata->madapter_info.os_type);
	return len;
}

static struct class_device_attribute ibmvscsi_host_os_type = {
	.attr = {
		 .name = "os_type",
		 .mode = S_IRUGO,
		 },
	.show = show_host_os_type,
};

static ssize_t show_host_config(struct class_device *class_dev, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(class_dev);
	struct ibmvscsi_host_data *hostdata =
	    (struct ibmvscsi_host_data *)shost->hostdata;

	/* returns null-terminated host config data */
	if (ibmvscsi_do_host_config(hostdata, buf, PAGE_SIZE) == 0)
		return strlen(buf);
	else
		return 0;
}

static struct class_device_attribute ibmvscsi_host_config = {
	.attr = {
		 .name = "config",
		 .mode = S_IRUGO,
		 },
	.show = show_host_config,
};

static struct class_device_attribute *ibmvscsi_attrs[] = {
	&ibmvscsi_host_srp_version,
	&ibmvscsi_host_partition_name,
	&ibmvscsi_host_partition_number,
	&ibmvscsi_host_mad_version,
	&ibmvscsi_host_os_type,
	&ibmvscsi_host_config,
	NULL
};

/* ------------------------------------------------------------
 * SCSI driver registration
 */
static struct scsi_host_template driver_template = {
	.module = THIS_MODULE,
	.name = "IBM POWER Virtual SCSI Adapter " IBMVSCSI_VERSION,
	.proc_name = "ibmvscsi",
	.queuecommand = ibmvscsi_queuecommand,
	.eh_abort_handler = ibmvscsi_eh_abort_handler,
	.eh_device_reset_handler = ibmvscsi_eh_device_reset_handler,
	.eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
	.slave_configure = ibmvscsi_slave_configure,
	.change_queue_depth = ibmvscsi_change_queue_depth,
	.cmd_per_lun = 16,
	.can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
	.this_id = -1,
	.sg_tablesize = SG_ALL,
	.use_clustering = ENABLE_CLUSTERING,
	.shost_attrs = ibmvscsi_attrs,
};

/**
 * Called by bus code for each adapter
 */
static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
{
	struct ibmvscsi_host_data *hostdata;
	struct Scsi_Host *host;
	struct device *dev = &vdev->dev;
	unsigned long wait_switch = 0;
	int rc;

	vdev->dev.driver_data = NULL;

	driver_template.can_queue = max_requests;
	host = scsi_host_alloc(&driver_template, sizeof(*hostdata));
	if (!host) {
		dev_err(&vdev->dev, "couldn't allocate host data\n");
		goto scsi_host_alloc_failed;
	}

	hostdata = (struct ibmvscsi_host_data *)host->hostdata;
	memset(hostdata, 0x00, sizeof(*hostdata));
	INIT_LIST_HEAD(&hostdata->sent);
	hostdata->host = host;
	hostdata->dev = dev;
	atomic_set(&hostdata->request_limit, -1);
	hostdata->host->max_sectors = 32 * 8; /* default max I/O 32 pages */

	rc = ibmvscsi_init_crq_queue(&hostdata->queue, hostdata, max_requests);
	if (rc != 0 && rc != H_RESOURCE) {
		dev_err(&vdev->dev, "couldn't initialize crq. rc=%d\n", rc);
		goto init_crq_failed;
	}
	if (initialize_event_pool(&hostdata->pool, max_requests, hostdata) != 0) {
		dev_err(&vdev->dev, "couldn't initialize event pool\n");
		goto init_pool_failed;
	}

	host->max_lun = 8;
	host->max_id = max_id;
	host->max_channel = max_channel;

	if (scsi_add_host(hostdata->host, hostdata->dev))
		goto add_host_failed;

	/* Try to send an initialization message.  Note that this is allowed
	 * to fail if the other end is not acive.  In that case we don't
	 * want to scan
	 */
	if (ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0) == 0
	    || rc == H_RESOURCE) {
		/*
		 * Wait around max init_timeout secs for the adapter to finish
		 * initializing. When we are done initializing, we will have a
		 * valid request_limit.  We don't want Linux scanning before
		 * we are ready.
		 */
		for (wait_switch = jiffies + (init_timeout * HZ);
		     time_before(jiffies, wait_switch) &&
		     atomic_read(&hostdata->request_limit) < 2;) {

			msleep(10);
		}

		/* if we now have a valid request_limit, initiate a scan */
		if (atomic_read(&hostdata->request_limit) > 0)
			scsi_scan_host(host);
	}

	vdev->dev.driver_data = hostdata;
	return 0;

      add_host_failed:
	release_event_pool(&hostdata->pool, hostdata);
      init_pool_failed:
	ibmvscsi_release_crq_queue(&hostdata->queue, hostdata, max_requests);
      init_crq_failed:
	scsi_host_put(host);
      scsi_host_alloc_failed:
	return -1;
}

static int ibmvscsi_remove(struct vio_dev *vdev)
{
	struct ibmvscsi_host_data *hostdata = vdev->dev.driver_data;
	release_event_pool(&hostdata->pool, hostdata);
	ibmvscsi_release_crq_queue(&hostdata->queue, hostdata,
				   max_requests);
	
	scsi_remove_host(hostdata->host);
	scsi_host_put(hostdata->host);

	return 0;
}

/**
 * ibmvscsi_device_table: Used by vio.c to match devices in the device tree we 
 * support.
 */
static struct vio_device_id ibmvscsi_device_table[] __devinitdata = {
	{"vscsi", "IBM,v-scsi"},
	{ "", "" }
};
MODULE_DEVICE_TABLE(vio, ibmvscsi_device_table);

static struct vio_driver ibmvscsi_driver = {
	.id_table = ibmvscsi_device_table,
	.probe = ibmvscsi_probe,
	.remove = ibmvscsi_remove,
	.driver = {
		.name = "ibmvscsi",
		.owner = THIS_MODULE,
	}
};

int __init ibmvscsi_module_init(void)
{
	return vio_register_driver(&ibmvscsi_driver);
}

void __exit ibmvscsi_module_exit(void)
{
	vio_unregister_driver(&ibmvscsi_driver);
}

module_init(ibmvscsi_module_init);
module_exit(ibmvscsi_module_exit);
OpenPOWER on IntegriCloud