summaryrefslogtreecommitdiff
path: root/drivers/scsi/scsi_transport_spi.c
blob: 2442d4d2e3f38f2d08fda8548dca91c73b15a579 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/* 
 *  Parallel SCSI (SPI) transport specific attributes exported to sysfs.
 *
 *  Copyright (c) 2003 Silicon Graphics, Inc.  All rights reserved.
 *  Copyright (c) 2004, 2005 James Bottomley <James.Bottomley@SteelEye.com>
 */
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <scsi/scsi.h>
#include "scsi_priv.h"
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_spi.h>

#define SPI_NUM_ATTRS 14	/* increase this if you add attributes */
#define SPI_OTHER_ATTRS 1	/* Increase this if you add "always
				 * on" attributes */
#define SPI_HOST_ATTRS	1

#define SPI_MAX_ECHO_BUFFER_SIZE	4096

#define DV_LOOPS	3
#define DV_TIMEOUT	(10*HZ)
#define DV_RETRIES	3	/* should only need at most 
				 * two cc/ua clears */

/* Our blacklist flags */
enum {
	SPI_BLIST_NOIUS = (__force blist_flags_t)0x1,
};

/* blacklist table, modelled on scsi_devinfo.c */
static struct {
	char *vendor;
	char *model;
	blist_flags_t flags;
} spi_static_device_list[] __initdata = {
	{"HP", "Ultrium 3-SCSI", SPI_BLIST_NOIUS },
	{"IBM", "ULTRIUM-TD3", SPI_BLIST_NOIUS },
	{NULL, NULL, 0}
};

/* Private data accessors (keep these out of the header file) */
#define spi_dv_in_progress(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_in_progress)
#define spi_dv_mutex(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_mutex)

struct spi_internal {
	struct scsi_transport_template t;
	struct spi_function_template *f;
};

#define to_spi_internal(tmpl)	container_of(tmpl, struct spi_internal, t)

static const int ppr_to_ps[] = {
	/* The PPR values 0-6 are reserved, fill them in when
	 * the committee defines them */
	-1,			/* 0x00 */
	-1,			/* 0x01 */
	-1,			/* 0x02 */
	-1,			/* 0x03 */
	-1,			/* 0x04 */
	-1,			/* 0x05 */
	-1,			/* 0x06 */
	 3125,			/* 0x07 */
	 6250,			/* 0x08 */
	12500,			/* 0x09 */
	25000,			/* 0x0a */
	30300,			/* 0x0b */
	50000,			/* 0x0c */
};
/* The PPR values at which you calculate the period in ns by multiplying
 * by 4 */
#define SPI_STATIC_PPR	0x0c

static int sprint_frac(char *dest, int value, int denom)
{
	int frac = value % denom;
	int result = sprintf(dest, "%d", value / denom);

	if (frac == 0)
		return result;
	dest[result++] = '.';

	do {
		denom /= 10;
		sprintf(dest + result, "%d", frac / denom);
		result++;
		frac %= denom;
	} while (frac);

	dest[result++] = '\0';
	return result;
}

static int spi_execute(struct scsi_device *sdev, const void *cmd,
		       enum req_op op, void *buffer, unsigned int bufflen,
		       struct scsi_sense_hdr *sshdr)
{
	int i, result;
	struct scsi_sense_hdr sshdr_tmp;
	blk_opf_t opf = op | REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
			REQ_FAILFAST_DRIVER;
	const struct scsi_exec_args exec_args = {
		.req_flags = BLK_MQ_REQ_PM,
		.sshdr = sshdr ? : &sshdr_tmp,
	};

	sshdr = exec_args.sshdr;

	for(i = 0; i < DV_RETRIES; i++) {
		/*
		 * The purpose of the RQF_PM flag below is to bypass the
		 * SDEV_QUIESCE state.
		 */
		result = scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen,
					  DV_TIMEOUT, 1, &exec_args);
		if (result < 0 || !scsi_sense_valid(sshdr) ||
		    sshdr->sense_key != UNIT_ATTENTION)
			break;
	}
	return result;
}

static struct {
	enum spi_signal_type	value;
	char			*name;
} signal_types[] = {
	{ SPI_SIGNAL_UNKNOWN, "unknown" },
	{ SPI_SIGNAL_SE, "SE" },
	{ SPI_SIGNAL_LVD, "LVD" },
	{ SPI_SIGNAL_HVD, "HVD" },
};

static inline const char *spi_signal_to_string(enum spi_signal_type type)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {
		if (type == signal_types[i].value)
			return signal_types[i].name;
	}
	return NULL;
}
static inline enum spi_signal_type spi_signal_to_value(const char *name)
{
	int i, len;

	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {
		len =  strlen(signal_types[i].name);
		if (strncmp(name, signal_types[i].name, len) == 0 &&
		    (name[len] == '\n' || name[len] == '\0'))
			return signal_types[i].value;
	}
	return SPI_SIGNAL_UNKNOWN;
}

static int spi_host_setup(struct transport_container *tc, struct device *dev,
			  struct device *cdev)
{
	struct Scsi_Host *shost = dev_to_shost(dev);

	spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;

	return 0;
}

static int spi_host_configure(struct transport_container *tc,
			      struct device *dev,
			      struct device *cdev);

static DECLARE_TRANSPORT_CLASS(spi_host_class,
			       "spi_host",
			       spi_host_setup,
			       NULL,
			       spi_host_configure);

static int spi_host_match(struct attribute_container *cont,
			  struct device *dev)
{
	struct Scsi_Host *shost;

	if (!scsi_is_host_device(dev))
		return 0;

	shost = dev_to_shost(dev);
	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
	    != &spi_host_class.class)
		return 0;

	return &shost->transportt->host_attrs.ac == cont;
}

static int spi_target_configure(struct transport_container *tc,
				struct device *dev,
				struct device *cdev);

static int spi_device_configure(struct transport_container *tc,
				struct device *dev,
				struct device *cdev)
{
	struct scsi_device *sdev = to_scsi_device(dev);
	struct scsi_target *starget = sdev->sdev_target;
	blist_flags_t bflags;

	bflags = scsi_get_device_flags_keyed(sdev, &sdev->inquiry[8],
					     &sdev->inquiry[16],
					     SCSI_DEVINFO_SPI);

	/* Populate the target capability fields with the values
	 * gleaned from the device inquiry */

	spi_support_sync(starget) = scsi_device_sync(sdev);
	spi_support_wide(starget) = scsi_device_wide(sdev);
	spi_support_dt(starget) = scsi_device_dt(sdev);
	spi_support_dt_only(starget) = scsi_device_dt_only(sdev);
	spi_support_ius(starget) = scsi_device_ius(sdev);
	if (bflags & SPI_BLIST_NOIUS) {
		dev_info(dev, "Information Units disabled by blacklist\n");
		spi_support_ius(starget) = 0;
	}
	spi_support_qas(starget) = scsi_device_qas(sdev);

	return 0;
}

static int spi_setup_transport_attrs(struct transport_container *tc,
				     struct device *dev,
				     struct device *cdev)
{
	struct scsi_target *starget = to_scsi_target(dev);

	spi_period(starget) = -1;	/* illegal value */
	spi_min_period(starget) = 0;
	spi_offset(starget) = 0;	/* async */
	spi_max_offset(starget) = 255;
	spi_width(starget) = 0;	/* narrow */
	spi_max_width(starget) = 1;
	spi_iu(starget) = 0;	/* no IU */
	spi_max_iu(starget) = 1;
	spi_dt(starget) = 0;	/* ST */
	spi_qas(starget) = 0;
	spi_max_qas(starget) = 1;
	spi_wr_flow(starget) = 0;
	spi_rd_strm(starget) = 0;
	spi_rti(starget) = 0;
	spi_pcomp_en(starget) = 0;
	spi_hold_mcs(starget) = 0;
	spi_dv_pending(starget) = 0;
	spi_dv_in_progress(starget) = 0;
	spi_initial_dv(starget) = 0;
	mutex_init(&spi_dv_mutex(starget));

	return 0;
}

#define spi_transport_show_simple(field, format_string)			\
									\
static ssize_t								\
show_spi_transport_##field(struct device *dev, 			\
			   struct device_attribute *attr, char *buf)	\
{									\
	struct scsi_target *starget = transport_class_to_starget(dev);	\
	struct spi_transport_attrs *tp;					\
									\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	return snprintf(buf, 20, format_string, tp->field);		\
}

#define spi_transport_store_simple(field, format_string)		\
									\
static ssize_t								\
store_spi_transport_##field(struct device *dev, 			\
			    struct device_attribute *attr, 		\
			    const char *buf, size_t count)		\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(dev);	\
	struct spi_transport_attrs *tp;					\
									\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	val = simple_strtoul(buf, NULL, 0);				\
	tp->field = val;						\
	return count;							\
}

#define spi_transport_show_function(field, format_string)		\
									\
static ssize_t								\
show_spi_transport_##field(struct device *dev, 			\
			   struct device_attribute *attr, char *buf)	\
{									\
	struct scsi_target *starget = transport_class_to_starget(dev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_transport_attrs *tp;					\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	if (i->f->get_##field)						\
		i->f->get_##field(starget);				\
	return snprintf(buf, 20, format_string, tp->field);		\
}

#define spi_transport_store_function(field, format_string)		\
static ssize_t								\
store_spi_transport_##field(struct device *dev, 			\
			    struct device_attribute *attr,		\
			    const char *buf, size_t count)		\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(dev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
									\
	if (!i->f->set_##field)						\
		return -EINVAL;						\
	val = simple_strtoul(buf, NULL, 0);				\
	i->f->set_##field(starget, val);				\
	return count;							\
}

#define spi_transport_store_max(field, format_string)			\
static ssize_t								\
store_spi_transport_##field(struct device *dev, 			\
			    struct device_attribute *attr,		\
			    const char *buf, size_t count)		\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(dev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
	struct spi_transport_attrs *tp					\
		= (struct spi_transport_attrs *)&starget->starget_data;	\
									\
	if (!i->f->set_##field)						\
		return -EINVAL;						\
	val = simple_strtoul(buf, NULL, 0);				\
	if (val > tp->max_##field)					\
		val = tp->max_##field;					\
	i->f->set_##field(starget, val);				\
	return count;							\
}

#define spi_transport_rd_attr(field, format_string)			\
	spi_transport_show_function(field, format_string)		\
	spi_transport_store_function(field, format_string)		\
static DEVICE_ATTR(field, S_IRUGO,				\
		   show_spi_transport_##field,			\
		   store_spi_transport_##field);

#define spi_transport_simple_attr(field, format_string)			\
	spi_transport_show_simple(field, format_string)			\
	spi_transport_store_simple(field, format_string)		\
static DEVICE_ATTR(field, S_IRUGO,				\
		   show_spi_transport_##field,			\
		   store_spi_transport_##field);

#define spi_transport_max_attr(field, format_string)			\
	spi_transport_show_function(field, format_string)		\
	spi_transport_store_max(field, format_string)			\
	spi_transport_simple_attr(max_##field, format_string)		\
static DEVICE_ATTR(field, S_IRUGO,				\
		   show_spi_transport_##field,			\
		   store_spi_transport_##field);

/* The Parallel SCSI Tranport Attributes: */
spi_transport_max_attr(offset, "%d\n");
spi_transport_max_attr(width, "%d\n");
spi_transport_max_attr(iu, "%d\n");
spi_transport_rd_attr(dt, "%d\n");
spi_transport_max_attr(qas, "%d\n");
spi_transport_rd_attr(wr_flow, "%d\n");
spi_transport_rd_attr(rd_strm, "%d\n");
spi_transport_rd_attr(rti, "%d\n");
spi_transport_rd_attr(pcomp_en, "%d\n");
spi_transport_rd_attr(hold_mcs, "%d\n");

/* we only care about the first child device that's a real SCSI device
 * so we return 1 to terminate the iteration when we find it */
static int child_iter(struct device *dev, void *data)
{
	if (!scsi_is_sdev_device(dev))
		return 0;

	spi_dv_device(to_scsi_device(dev));
	return 1;
}

static ssize_t
store_spi_revalidate(struct device *dev, struct device_attribute *attr,
		     const char *buf, size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(dev);

	device_for_each_child(&starget->dev, NULL, child_iter);
	return count;
}
static DEVICE_ATTR(revalidate, S_IWUSR, NULL, store_spi_revalidate);

/* Translate the period into ns according to the current spec
 * for SDTR/PPR messages */
static int period_to_str(char *buf, int period)
{
	int len, picosec;

	if (period < 0 || period > 0xff) {
		picosec = -1;
	} else if (period <= SPI_STATIC_PPR) {
		picosec = ppr_to_ps[period];
	} else {
		picosec = period * 4000;
	}

	if (picosec == -1) {
		len = sprintf(buf, "reserved");
	} else {
		len = sprint_frac(buf, picosec, 1000);
	}

	return len;
}

static ssize_t
show_spi_transport_period_helper(char *buf, int period)
{
	int len = period_to_str(buf, period);
	buf[len++] = '\n';
	buf[len] = '\0';
	return len;
}

static ssize_t
store_spi_transport_period_helper(struct device *dev, const char *buf,
				  size_t count, int *periodp)
{
	int j, picosec, period = -1;
	char *endp;

	picosec = simple_strtoul(buf, &endp, 10) * 1000;
	if (*endp == '.') {
		int mult = 100;
		do {
			endp++;
			if (!isdigit(*endp))
				break;
			picosec += (*endp - '0') * mult;
			mult /= 10;
		} while (mult > 0);
	}

	for (j = 0; j <= SPI_STATIC_PPR; j++) {
		if (ppr_to_ps[j] < picosec)
			continue;
		period = j;
		break;
	}

	if (period == -1)
		period = picosec / 4000;

	if (period > 0xff)
		period = 0xff;

	*periodp = period;

	return count;
}

static ssize_t
show_spi_transport_period(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	struct scsi_target *starget = transport_class_to_starget(dev);
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	if (i->f->get_period)
		i->f->get_period(starget);

	return show_spi_transport_period_helper(buf, tp->period);
}

static ssize_t
store_spi_transport_period(struct device *cdev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;
	int period, retval;

	if (!i->f->set_period)
		return -EINVAL;

	retval = store_spi_transport_period_helper(cdev, buf, count, &period);

	if (period < tp->min_period)
		period = tp->min_period;

	i->f->set_period(starget, period);

	return retval;
}

static DEVICE_ATTR(period, S_IRUGO,
		   show_spi_transport_period,
		   store_spi_transport_period);

static ssize_t
show_spi_transport_min_period(struct device *cdev,
			      struct device_attribute *attr, char *buf)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	if (!i->f->set_period)
		return -EINVAL;

	return show_spi_transport_period_helper(buf, tp->min_period);
}

static ssize_t
store_spi_transport_min_period(struct device *cdev,
			       struct device_attribute *attr,
			       const char *buf, size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	return store_spi_transport_period_helper(cdev, buf, count,
						 &tp->min_period);
}


static DEVICE_ATTR(min_period, S_IRUGO,
		   show_spi_transport_min_period,
		   store_spi_transport_min_period);


static ssize_t show_spi_host_signalling(struct device *cdev,
					struct device_attribute *attr,
					char *buf)
{
	struct Scsi_Host *shost = transport_class_to_shost(cdev);
	struct spi_internal *i = to_spi_internal(shost->transportt);

	if (i->f->get_signalling)
		i->f->get_signalling(shost);

	return sprintf(buf, "%s\n", spi_signal_to_string(spi_signalling(shost)));
}
static ssize_t store_spi_host_signalling(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	struct Scsi_Host *shost = transport_class_to_shost(dev);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	enum spi_signal_type type = spi_signal_to_value(buf);

	if (!i->f->set_signalling)
		return -EINVAL;

	if (type != SPI_SIGNAL_UNKNOWN)
		i->f->set_signalling(shost, type);

	return count;
}
static DEVICE_ATTR(signalling, S_IRUGO,
		   show_spi_host_signalling,
		   store_spi_host_signalling);

static ssize_t show_spi_host_width(struct device *cdev,
				      struct device_attribute *attr,
				      char *buf)
{
	struct Scsi_Host *shost = transport_class_to_shost(cdev);

	return sprintf(buf, "%s\n", shost->max_id == 16 ? "wide" : "narrow");
}
static DEVICE_ATTR(host_width, S_IRUGO,
		   show_spi_host_width, NULL);

static ssize_t show_spi_host_hba_id(struct device *cdev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct Scsi_Host *shost = transport_class_to_shost(cdev);

	return sprintf(buf, "%d\n", shost->this_id);
}
static DEVICE_ATTR(hba_id, S_IRUGO,
		   show_spi_host_hba_id, NULL);

#define DV_SET(x, y)			\
	if(i->f->set_##x)		\
		i->f->set_##x(sdev->sdev_target, y)

enum spi_compare_returns {
	SPI_COMPARE_SUCCESS,
	SPI_COMPARE_FAILURE,
	SPI_COMPARE_SKIP_TEST,
};


/* This is for read/write Domain Validation:  If the device supports
 * an echo buffer, we do read/write tests to it */
static enum spi_compare_returns
spi_dv_device_echo_buffer(struct scsi_device *sdev, u8 *buffer,
			  u8 *ptr, const int retries)
{
	int len = ptr - buffer;
	int j, k, r, result;
	unsigned int pattern = 0x0000ffff;
	struct scsi_sense_hdr sshdr;

	const char spi_write_buffer[] = {
		WRITE_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
	};
	const char spi_read_buffer[] = {
		READ_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
	};

	/* set up the pattern buffer.  Doesn't matter if we spill
	 * slightly beyond since that's where the read buffer is */
	for (j = 0; j < len; ) {

		/* fill the buffer with counting (test a) */
		for ( ; j < min(len, 32); j++)
			buffer[j] = j;
		k = j;
		/* fill the buffer with alternating words of 0x0 and
		 * 0xffff (test b) */
		for ( ; j < min(len, k + 32); j += 2) {
			u16 *word = (u16 *)&buffer[j];
			
			*word = (j & 0x02) ? 0x0000 : 0xffff;
		}
		k = j;
		/* fill with crosstalk (alternating 0x5555 0xaaa)
                 * (test c) */
		for ( ; j < min(len, k + 32); j += 2) {
			u16 *word = (u16 *)&buffer[j];

			*word = (j & 0x02) ? 0x5555 : 0xaaaa;
		}
		k = j;
		/* fill with shifting bits (test d) */
		for ( ; j < min(len, k + 32); j += 4) {
			u32 *word = (unsigned int *)&buffer[j];
			u32 roll = (pattern & 0x80000000) ? 1 : 0;
			
			*word = pattern;
			pattern = (pattern << 1) | roll;
		}
		/* don't bother with random data (test e) */
	}

	for (r = 0; r < retries; r++) {
		result = spi_execute(sdev, spi_write_buffer, REQ_OP_DRV_OUT,
				     buffer, len, &sshdr);
		if(result || !scsi_device_online(sdev)) {

			scsi_device_set_state(sdev, SDEV_QUIESCE);
			if (scsi_sense_valid(&sshdr)
			    && sshdr.sense_key == ILLEGAL_REQUEST
			    /* INVALID FIELD IN CDB */
			    && sshdr.asc == 0x24 && sshdr.ascq == 0x00)
				/* This would mean that the drive lied
				 * to us about supporting an echo
				 * buffer (unfortunately some Western
				 * Digital drives do precisely this)
				 */
				return SPI_COMPARE_SKIP_TEST;


			sdev_printk(KERN_ERR, sdev, "Write Buffer failure %x\n", result);
			return SPI_COMPARE_FAILURE;
		}

		memset(ptr, 0, len);
		spi_execute(sdev, spi_read_buffer, REQ_OP_DRV_IN,
			    ptr, len, NULL);
		scsi_device_set_state(sdev, SDEV_QUIESCE);

		if (memcmp(buffer, ptr, len) != 0)
			return SPI_COMPARE_FAILURE;
	}
	return SPI_COMPARE_SUCCESS;
}

/* This is for the simplest form of Domain Validation: a read test
 * on the inquiry data from the device */
static enum spi_compare_returns
spi_dv_device_compare_inquiry(struct scsi_device *sdev, u8 *buffer,
			      u8 *ptr, const int retries)
{
	int r, result;
	const int len = sdev->inquiry_len;
	const char spi_inquiry[] = {
		INQUIRY, 0, 0, 0, len, 0
	};

	for (r = 0; r < retries; r++) {
		memset(ptr, 0, len);

		result = spi_execute(sdev, spi_inquiry, REQ_OP_DRV_IN,
				     ptr, len, NULL);
		
		if(result || !scsi_device_online(sdev)) {
			scsi_device_set_state(sdev, SDEV_QUIESCE);
			return SPI_COMPARE_FAILURE;
		}

		/* If we don't have the inquiry data already, the
		 * first read gets it */
		if (ptr == buffer) {
			ptr += len;
			--r;
			continue;
		}

		if (memcmp(buffer, ptr, len) != 0)
			/* failure */
			return SPI_COMPARE_FAILURE;
	}
	return SPI_COMPARE_SUCCESS;
}

static enum spi_compare_returns
spi_dv_retrain(struct scsi_device *sdev, u8 *buffer, u8 *ptr,
	       enum spi_compare_returns 
	       (*compare_fn)(struct scsi_device *, u8 *, u8 *, int))
{
	struct spi_internal *i = to_spi_internal(sdev->host->transportt);
	struct scsi_target *starget = sdev->sdev_target;
	int period = 0, prevperiod = 0; 
	enum spi_compare_returns retval;


	for (;;) {
		int newperiod;
		retval = compare_fn(sdev, buffer, ptr, DV_LOOPS);

		if (retval == SPI_COMPARE_SUCCESS
		    || retval == SPI_COMPARE_SKIP_TEST)
			break;

		/* OK, retrain, fallback */
		if (i->f->get_iu)
			i->f->get_iu(starget);
		if (i->f->get_qas)
			i->f->get_qas(starget);
		if (i->f->get_period)
			i->f->get_period(sdev->sdev_target);

		/* Here's the fallback sequence; first try turning off
		 * IU, then QAS (if we can control them), then finally
		 * fall down the periods */
		if (i->f->set_iu && spi_iu(starget)) {
			starget_printk(KERN_ERR, starget, "Domain Validation Disabling Information Units\n");
			DV_SET(iu, 0);
		} else if (i->f->set_qas && spi_qas(starget)) {
			starget_printk(KERN_ERR, starget, "Domain Validation Disabling Quick Arbitration and Selection\n");
			DV_SET(qas, 0);
		} else {
			newperiod = spi_period(starget);
			period = newperiod > period ? newperiod : period;
			if (period < 0x0d)
				period++;
			else
				period += period >> 1;

			if (unlikely(period > 0xff || period == prevperiod)) {
				/* Total failure; set to async and return */
				starget_printk(KERN_ERR, starget, "Domain Validation Failure, dropping back to Asynchronous\n");
				DV_SET(offset, 0);
				return SPI_COMPARE_FAILURE;
			}
			starget_printk(KERN_ERR, starget, "Domain Validation detected failure, dropping back\n");
			DV_SET(period, period);
			prevperiod = period;
		}
	}
	return retval;
}

static int
spi_dv_device_get_echo_buffer(struct scsi_device *sdev, u8 *buffer)
{
	int l, result;

	/* first off do a test unit ready.  This can error out 
	 * because of reservations or some other reason.  If it
	 * fails, the device won't let us write to the echo buffer
	 * so just return failure */
	
	static const char spi_test_unit_ready[] = {
		TEST_UNIT_READY, 0, 0, 0, 0, 0
	};

	static const char spi_read_buffer_descriptor[] = {
		READ_BUFFER, 0x0b, 0, 0, 0, 0, 0, 0, 4, 0
	};

	
	/* We send a set of three TURs to clear any outstanding 
	 * unit attention conditions if they exist (Otherwise the
	 * buffer tests won't be happy).  If the TUR still fails
	 * (reservation conflict, device not ready, etc) just
	 * skip the write tests */
	for (l = 0; ; l++) {
		result = spi_execute(sdev, spi_test_unit_ready, REQ_OP_DRV_IN,
				     NULL, 0, NULL);

		if(result) {
			if(l >= 3)
				return 0;
		} else {
			/* TUR succeeded */
			break;
		}
	}

	result = spi_execute(sdev, spi_read_buffer_descriptor, 
			     REQ_OP_DRV_IN, buffer, 4, NULL);

	if (result)
		/* Device has no echo buffer */
		return 0;

	return buffer[3] + ((buffer[2] & 0x1f) << 8);
}

static void
spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
{
	struct spi_internal *i = to_spi_internal(sdev->host->transportt);
	struct scsi_target *starget = sdev->sdev_target;
	struct Scsi_Host *shost = sdev->host;
	int len = sdev->inquiry_len;
	int min_period = spi_min_period(starget);
	int max_width = spi_max_width(starget);
	/* first set us up for narrow async */
	DV_SET(offset, 0);
	DV_SET(width, 0);

	if (spi_dv_device_compare_inquiry(sdev, buffer, buffer, DV_LOOPS)
	    != SPI_COMPARE_SUCCESS) {
		starget_printk(KERN_ERR, starget, "Domain Validation Initial Inquiry Failed\n");
		/* FIXME: should probably offline the device here? */
		return;
	}

	if (!spi_support_wide(starget)) {
		spi_max_width(starget) = 0;
		max_width = 0;
	}

	/* test width */
	if (i->f->set_width && max_width) {
		i->f->set_width(starget, 1);

		if (spi_dv_device_compare_inquiry(sdev, buffer,
						   buffer + len,
						   DV_LOOPS)
		    != SPI_COMPARE_SUCCESS) {
			starget_printk(KERN_ERR, starget, "Wide Transfers Fail\n");
			i->f->set_width(starget, 0);
			/* Make sure we don't force wide back on by asking
			 * for a transfer period that requires it */
			max_width = 0;
			if (min_period < 10)
				min_period = 10;
		}
	}

	if (!i->f->set_period)
		return;

	/* device can't handle synchronous */
	if (!spi_support_sync(starget) && !spi_support_dt(starget))
		return;

	/* len == -1 is the signal that we need to ascertain the
	 * presence of an echo buffer before trying to use it.  len ==
	 * 0 means we don't have an echo buffer */
	len = -1;

 retry:

	/* now set up to the maximum */
	DV_SET(offset, spi_max_offset(starget));
	DV_SET(period, min_period);

	/* try QAS requests; this should be harmless to set if the
	 * target supports it */
	if (spi_support_qas(starget) && spi_max_qas(starget)) {
		DV_SET(qas, 1);
	} else {
		DV_SET(qas, 0);
	}

	if (spi_support_ius(starget) && spi_max_iu(starget) &&
	    min_period < 9) {
		/* This u320 (or u640). Set IU transfers */
		DV_SET(iu, 1);
		/* Then set the optional parameters */
		DV_SET(rd_strm, 1);
		DV_SET(wr_flow, 1);
		DV_SET(rti, 1);
		if (min_period == 8)
			DV_SET(pcomp_en, 1);
	} else {
		DV_SET(iu, 0);
	}

	/* now that we've done all this, actually check the bus
	 * signal type (if known).  Some devices are stupid on
	 * a SE bus and still claim they can try LVD only settings */
	if (i->f->get_signalling)
		i->f->get_signalling(shost);
	if (spi_signalling(shost) == SPI_SIGNAL_SE ||
	    spi_signalling(shost) == SPI_SIGNAL_HVD ||
	    !spi_support_dt(starget)) {
		DV_SET(dt, 0);
	} else {
		DV_SET(dt, 1);
	}
	/* set width last because it will pull all the other
	 * parameters down to required values */
	DV_SET(width, max_width);

	/* Do the read only INQUIRY tests */
	spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
		       spi_dv_device_compare_inquiry);
	/* See if we actually managed to negotiate and sustain DT */
	if (i->f->get_dt)
		i->f->get_dt(starget);

	/* see if the device has an echo buffer.  If it does we can do
	 * the SPI pattern write tests.  Because of some broken
	 * devices, we *only* try this on a device that has actually
	 * negotiated DT */

	if (len == -1 && spi_dt(starget))
		len = spi_dv_device_get_echo_buffer(sdev, buffer);

	if (len <= 0) {
		starget_printk(KERN_INFO, starget, "Domain Validation skipping write tests\n");
		return;
	}

	if (len > SPI_MAX_ECHO_BUFFER_SIZE) {
		starget_printk(KERN_WARNING, starget, "Echo buffer size %d is too big, trimming to %d\n", len, SPI_MAX_ECHO_BUFFER_SIZE);
		len = SPI_MAX_ECHO_BUFFER_SIZE;
	}

	if (spi_dv_retrain(sdev, buffer, buffer + len,
			   spi_dv_device_echo_buffer)
	    == SPI_COMPARE_SKIP_TEST) {
		/* OK, the stupid drive can't do a write echo buffer
		 * test after all, fall back to the read tests */
		len = 0;
		goto retry;
	}
}


/**	spi_dv_device - Do Domain Validation on the device
 *	@sdev:		scsi device to validate
 *
 *	Performs the domain validation on the given device in the
 *	current execution thread.  Since DV operations may sleep,
 *	the current thread must have user context.  Also no SCSI
 *	related locks that would deadlock I/O issued by the DV may
 *	be held.
 */
void
spi_dv_device(struct scsi_device *sdev)
{
	struct scsi_target *starget = sdev->sdev_target;
	const int len = SPI_MAX_ECHO_BUFFER_SIZE*2;
	unsigned int sleep_flags;
	u8 *buffer;

	/*
	 * Because this function and the power management code both call
	 * scsi_device_quiesce(), it is not safe to perform domain validation
	 * while suspend or resume is in progress. Hence the
	 * lock/unlock_system_sleep() calls.
	 */
	sleep_flags = lock_system_sleep();

	if (scsi_autopm_get_device(sdev))
		goto unlock_system_sleep;

	if (unlikely(spi_dv_in_progress(starget)))
		goto put_autopm;

	if (unlikely(scsi_device_get(sdev)))
		goto put_autopm;

	spi_dv_in_progress(starget) = 1;

	buffer = kzalloc(len, GFP_KERNEL);

	if (unlikely(!buffer))
		goto put_sdev;

	/* We need to verify that the actual device will quiesce; the
	 * later target quiesce is just a nice to have */
	if (unlikely(scsi_device_quiesce(sdev)))
		goto free_buffer;

	scsi_target_quiesce(starget);

	spi_dv_pending(starget) = 1;
	mutex_lock(&spi_dv_mutex(starget));

	starget_printk(KERN_INFO, starget, "Beginning Domain Validation\n");

	spi_dv_device_internal(sdev, buffer);

	starget_printk(KERN_INFO, starget, "Ending Domain Validation\n");

	mutex_unlock(&spi_dv_mutex(starget));
	spi_dv_pending(starget) = 0;

	scsi_target_resume(starget);

	spi_initial_dv(starget) = 1;

free_buffer:
	kfree(buffer);

put_sdev:
	spi_dv_in_progress(starget) = 0;
	scsi_device_put(sdev);
put_autopm:
	scsi_autopm_put_device(sdev);

unlock_system_sleep:
	unlock_system_sleep(sleep_flags);
}
EXPORT_SYMBOL(spi_dv_device);

struct work_queue_wrapper {
	struct work_struct	work;
	struct scsi_device	*sdev;
};

static void
spi_dv_device_work_wrapper(struct work_struct *work)
{
	struct work_queue_wrapper *wqw =
		container_of(work, struct work_queue_wrapper, work);
	struct scsi_device *sdev = wqw->sdev;

	kfree(wqw);
	spi_dv_device(sdev);
	spi_dv_pending(sdev->sdev_target) = 0;
	scsi_device_put(sdev);
}


/**
 *	spi_schedule_dv_device - schedule domain validation to occur on the device
 *	@sdev:	The device to validate
 *
 *	Identical to spi_dv_device() above, except that the DV will be
 *	scheduled to occur in a workqueue later.  All memory allocations
 *	are atomic, so may be called from any context including those holding
 *	SCSI locks.
 */
void
spi_schedule_dv_device(struct scsi_device *sdev)
{
	struct work_queue_wrapper *wqw =
		kmalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);

	if (unlikely(!wqw))
		return;

	if (unlikely(spi_dv_pending(sdev->sdev_target))) {
		kfree(wqw);
		return;
	}
	/* Set pending early (dv_device doesn't check it, only sets it) */
	spi_dv_pending(sdev->sdev_target) = 1;
	if (unlikely(scsi_device_get(sdev))) {
		kfree(wqw);
		spi_dv_pending(sdev->sdev_target) = 0;
		return;
	}

	INIT_WORK(&wqw->work, spi_dv_device_work_wrapper);
	wqw->sdev = sdev;

	schedule_work(&wqw->work);
}
EXPORT_SYMBOL(spi_schedule_dv_device);

/**
 * spi_display_xfer_agreement - Print the current target transfer agreement
 * @starget: The target for which to display the agreement
 *
 * Each SPI port is required to maintain a transfer agreement for each
 * other port on the bus.  This function prints a one-line summary of
 * the current agreement; more detailed information is available in sysfs.
 */
void spi_display_xfer_agreement(struct scsi_target *starget)
{
	struct spi_transport_attrs *tp;
	tp = (struct spi_transport_attrs *)&starget->starget_data;

	if (tp->offset > 0 && tp->period > 0) {
		unsigned int picosec, kb100;
		char *scsi = "FAST-?";
		char tmp[8];

		if (tp->period <= SPI_STATIC_PPR) {
			picosec = ppr_to_ps[tp->period];
			switch (tp->period) {
				case  7: scsi = "FAST-320"; break;
				case  8: scsi = "FAST-160"; break;
				case  9: scsi = "FAST-80"; break;
				case 10:
				case 11: scsi = "FAST-40"; break;
				case 12: scsi = "FAST-20"; break;
			}
		} else {
			picosec = tp->period * 4000;
			if (tp->period < 25)
				scsi = "FAST-20";
			else if (tp->period < 50)
				scsi = "FAST-10";
			else
				scsi = "FAST-5";
		}

		kb100 = (10000000 + picosec / 2) / picosec;
		if (tp->width)
			kb100 *= 2;
		sprint_frac(tmp, picosec, 1000);

		dev_info(&starget->dev,
			 "%s %sSCSI %d.%d MB/s %s%s%s%s%s%s%s%s (%s ns, offset %d)\n",
			 scsi, tp->width ? "WIDE " : "", kb100/10, kb100 % 10,
			 tp->dt ? "DT" : "ST",
			 tp->iu ? " IU" : "",
			 tp->qas  ? " QAS" : "",
			 tp->rd_strm ? " RDSTRM" : "",
			 tp->rti ? " RTI" : "",
			 tp->wr_flow ? " WRFLOW" : "",
			 tp->pcomp_en ? " PCOMP" : "",
			 tp->hold_mcs ? " HMCS" : "",
			 tmp, tp->offset);
	} else {
		dev_info(&starget->dev, "%sasynchronous\n",
				tp->width ? "wide " : "");
	}
}
EXPORT_SYMBOL(spi_display_xfer_agreement);

int spi_populate_width_msg(unsigned char *msg, int width)
{
	msg[0] = EXTENDED_MESSAGE;
	msg[1] = 2;
	msg[2] = EXTENDED_WDTR;
	msg[3] = width;
	return 4;
}
EXPORT_SYMBOL_GPL(spi_populate_width_msg);

int spi_populate_sync_msg(unsigned char *msg, int period, int offset)
{
	msg[0] = EXTENDED_MESSAGE;
	msg[1] = 3;
	msg[2] = EXTENDED_SDTR;
	msg[3] = period;
	msg[4] = offset;
	return 5;
}
EXPORT_SYMBOL_GPL(spi_populate_sync_msg);

int spi_populate_ppr_msg(unsigned char *msg, int period, int offset,
		int width, int options)
{
	msg[0] = EXTENDED_MESSAGE;
	msg[1] = 6;
	msg[2] = EXTENDED_PPR;
	msg[3] = period;
	msg[4] = 0;
	msg[5] = offset;
	msg[6] = width;
	msg[7] = options;
	return 8;
}
EXPORT_SYMBOL_GPL(spi_populate_ppr_msg);

/**
 * spi_populate_tag_msg - place a tag message in a buffer
 * @msg:	pointer to the area to place the tag
 * @cmd:	pointer to the scsi command for the tag
 *
 * Notes:
 *	designed to create the correct type of tag message for the 
 *	particular request.  Returns the size of the tag message.
 *	May return 0 if TCQ is disabled for this device.
 **/
int spi_populate_tag_msg(unsigned char *msg, struct scsi_cmnd *cmd)
{
        if (cmd->flags & SCMD_TAGGED) {
		*msg++ = SIMPLE_QUEUE_TAG;
		*msg++ = scsi_cmd_to_rq(cmd)->tag;
        	return 2;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(spi_populate_tag_msg);

#ifdef CONFIG_SCSI_CONSTANTS
static const char * const one_byte_msgs[] = {
/* 0x00 */ "Task Complete", NULL /* Extended Message */, "Save Pointers",
/* 0x03 */ "Restore Pointers", "Disconnect", "Initiator Error", 
/* 0x06 */ "Abort Task Set", "Message Reject", "Nop", "Message Parity Error",
/* 0x0a */ "Linked Command Complete", "Linked Command Complete w/flag",
/* 0x0c */ "Target Reset", "Abort Task", "Clear Task Set", 
/* 0x0f */ "Initiate Recovery", "Release Recovery",
/* 0x11 */ "Terminate Process", "Continue Task", "Target Transfer Disable",
/* 0x14 */ NULL, NULL, "Clear ACA", "LUN Reset"
};

static const char * const two_byte_msgs[] = {
/* 0x20 */ "Simple Queue Tag", "Head of Queue Tag", "Ordered Queue Tag",
/* 0x23 */ "Ignore Wide Residue", "ACA"
};

static const char * const extended_msgs[] = {
/* 0x00 */ "Modify Data Pointer", "Synchronous Data Transfer Request",
/* 0x02 */ "SCSI-I Extended Identify", "Wide Data Transfer Request",
/* 0x04 */ "Parallel Protocol Request", "Modify Bidirectional Data Pointer"
};

static void print_nego(const unsigned char *msg, int per, int off, int width)
{
	if (per) {
		char buf[20];
		period_to_str(buf, msg[per]);
		printk("period = %s ns ", buf);
	}

	if (off)
		printk("offset = %d ", msg[off]);
	if (width)
		printk("width = %d ", 8 << msg[width]);
}

static void print_ptr(const unsigned char *msg, int msb, const char *desc)
{
	int ptr = (msg[msb] << 24) | (msg[msb+1] << 16) | (msg[msb+2] << 8) |
			msg[msb+3];
	printk("%s = %d ", desc, ptr);
}

int spi_print_msg(const unsigned char *msg)
{
	int len = 1, i;
	if (msg[0] == EXTENDED_MESSAGE) {
		len = 2 + msg[1];
		if (len == 2)
			len += 256;
		if (msg[2] < ARRAY_SIZE(extended_msgs))
			printk ("%s ", extended_msgs[msg[2]]); 
		else 
			printk ("Extended Message, reserved code (0x%02x) ",
				(int) msg[2]);
		switch (msg[2]) {
		case EXTENDED_MODIFY_DATA_POINTER:
			print_ptr(msg, 3, "pointer");
			break;
		case EXTENDED_SDTR:
			print_nego(msg, 3, 4, 0);
			break;
		case EXTENDED_WDTR:
			print_nego(msg, 0, 0, 3);
			break;
		case EXTENDED_PPR:
			print_nego(msg, 3, 5, 6);
			break;
		case EXTENDED_MODIFY_BIDI_DATA_PTR:
			print_ptr(msg, 3, "out");
			print_ptr(msg, 7, "in");
			break;
		default:
		for (i = 2; i < len; ++i) 
			printk("%02x ", msg[i]);
		}
	/* Identify */
	} else if (msg[0] & 0x80) {
		printk("Identify disconnect %sallowed %s %d ",
			(msg[0] & 0x40) ? "" : "not ",
			(msg[0] & 0x20) ? "target routine" : "lun",
			msg[0] & 0x7);
	/* Normal One byte */
	} else if (msg[0] < 0x1f) {
		if (msg[0] < ARRAY_SIZE(one_byte_msgs) && one_byte_msgs[msg[0]])
			printk("%s ", one_byte_msgs[msg[0]]);
		else
			printk("reserved (%02x) ", msg[0]);
	} else if (msg[0] == 0x55) {
		printk("QAS Request ");
	/* Two byte */
	} else if (msg[0] <= 0x2f) {
		if ((msg[0] - 0x20) < ARRAY_SIZE(two_byte_msgs))
			printk("%s %02x ", two_byte_msgs[msg[0] - 0x20], 
				msg[1]);
		else 
			printk("reserved two byte (%02x %02x) ", 
				msg[0], msg[1]);
		len = 2;
	} else 
		printk("reserved ");
	return len;
}
EXPORT_SYMBOL(spi_print_msg);

#else  /* ifndef CONFIG_SCSI_CONSTANTS */

int spi_print_msg(const unsigned char *msg)
{
	int len = 1, i;

	if (msg[0] == EXTENDED_MESSAGE) {
		len = 2 + msg[1];
		if (len == 2)
			len += 256;
		for (i = 0; i < len; ++i)
			printk("%02x ", msg[i]);
	/* Identify */
	} else if (msg[0] & 0x80) {
		printk("%02x ", msg[0]);
	/* Normal One byte */
	} else if ((msg[0] < 0x1f) || (msg[0] == 0x55)) {
		printk("%02x ", msg[0]);
	/* Two byte */
	} else if (msg[0] <= 0x2f) {
		printk("%02x %02x", msg[0], msg[1]);
		len = 2;
	} else 
		printk("%02x ", msg[0]);
	return len;
}
EXPORT_SYMBOL(spi_print_msg);
#endif /* ! CONFIG_SCSI_CONSTANTS */

static int spi_device_match(struct attribute_container *cont,
			    struct device *dev)
{
	struct scsi_device *sdev;
	struct Scsi_Host *shost;
	struct spi_internal *i;

	if (!scsi_is_sdev_device(dev))
		return 0;

	sdev = to_scsi_device(dev);
	shost = sdev->host;
	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
	    != &spi_host_class.class)
		return 0;
	/* Note: this class has no device attributes, so it has
	 * no per-HBA allocation and thus we don't need to distinguish
	 * the attribute containers for the device */
	i = to_spi_internal(shost->transportt);
	if (i->f->deny_binding && i->f->deny_binding(sdev->sdev_target))
		return 0;
	return 1;
}

static int spi_target_match(struct attribute_container *cont,
			    struct device *dev)
{
	struct Scsi_Host *shost;
	struct scsi_target *starget;
	struct spi_internal *i;

	if (!scsi_is_target_device(dev))
		return 0;

	shost = dev_to_shost(dev->parent);
	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
	    != &spi_host_class.class)
		return 0;

	i = to_spi_internal(shost->transportt);
	starget = to_scsi_target(dev);

	if (i->f->deny_binding && i->f->deny_binding(starget))
		return 0;

	return &i->t.target_attrs.ac == cont;
}

static DECLARE_TRANSPORT_CLASS(spi_transport_class,
			       "spi_transport",
			       spi_setup_transport_attrs,
			       NULL,
			       spi_target_configure);

static DECLARE_ANON_TRANSPORT_CLASS(spi_device_class,
				    spi_device_match,
				    spi_device_configure);

static struct attribute *host_attributes[] = {
	&dev_attr_signalling.attr,
	&dev_attr_host_width.attr,
	&dev_attr_hba_id.attr,
	NULL
};

static struct attribute_group host_attribute_group = {
	.attrs = host_attributes,
};

static int spi_host_configure(struct transport_container *tc,
			      struct device *dev,
			      struct device *cdev)
{
	struct kobject *kobj = &cdev->kobj;
	struct Scsi_Host *shost = transport_class_to_shost(cdev);
	struct spi_internal *si = to_spi_internal(shost->transportt);
	struct attribute *attr = &dev_attr_signalling.attr;
	int rc = 0;

	if (si->f->set_signalling)
		rc = sysfs_chmod_file(kobj, attr, attr->mode | S_IWUSR);

	return rc;
}

/* returns true if we should be showing the variable.  Also
 * overloads the return by setting 1<<1 if the attribute should
 * be writeable */
#define TARGET_ATTRIBUTE_HELPER(name) \
	(si->f->show_##name ? S_IRUGO : 0) | \
	(si->f->set_##name ? S_IWUSR : 0)

static umode_t target_attribute_is_visible(struct kobject *kobj,
					  struct attribute *attr, int i)
{
	struct device *cdev = container_of(kobj, struct device, kobj);
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct Scsi_Host *shost = transport_class_to_shost(cdev);
	struct spi_internal *si = to_spi_internal(shost->transportt);

	if (attr == &dev_attr_period.attr &&
	    spi_support_sync(starget))
		return TARGET_ATTRIBUTE_HELPER(period);
	else if (attr == &dev_attr_min_period.attr &&
		 spi_support_sync(starget))
		return TARGET_ATTRIBUTE_HELPER(period);
	else if (attr == &dev_attr_offset.attr &&
		 spi_support_sync(starget))
		return TARGET_ATTRIBUTE_HELPER(offset);
	else if (attr == &dev_attr_max_offset.attr &&
		 spi_support_sync(starget))
		return TARGET_ATTRIBUTE_HELPER(offset);
	else if (attr == &dev_attr_width.attr &&
		 spi_support_wide(starget))
		return TARGET_ATTRIBUTE_HELPER(width);
	else if (attr == &dev_attr_max_width.attr &&
		 spi_support_wide(starget))
		return TARGET_ATTRIBUTE_HELPER(width);
	else if (attr == &dev_attr_iu.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(iu);
	else if (attr == &dev_attr_max_iu.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(iu);
	else if (attr == &dev_attr_dt.attr &&
		 spi_support_dt(starget))
		return TARGET_ATTRIBUTE_HELPER(dt);
	else if (attr == &dev_attr_qas.attr &&
		 spi_support_qas(starget))
		return TARGET_ATTRIBUTE_HELPER(qas);
	else if (attr == &dev_attr_max_qas.attr &&
		 spi_support_qas(starget))
		return TARGET_ATTRIBUTE_HELPER(qas);
	else if (attr == &dev_attr_wr_flow.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(wr_flow);
	else if (attr == &dev_attr_rd_strm.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(rd_strm);
	else if (attr == &dev_attr_rti.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(rti);
	else if (attr == &dev_attr_pcomp_en.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(pcomp_en);
	else if (attr == &dev_attr_hold_mcs.attr &&
		 spi_support_ius(starget))
		return TARGET_ATTRIBUTE_HELPER(hold_mcs);
	else if (attr == &dev_attr_revalidate.attr)
		return S_IWUSR;

	return 0;
}

static struct attribute *target_attributes[] = {
	&dev_attr_period.attr,
	&dev_attr_min_period.attr,
	&dev_attr_offset.attr,
	&dev_attr_max_offset.attr,
	&dev_attr_width.attr,
	&dev_attr_max_width.attr,
	&dev_attr_iu.attr,
	&dev_attr_max_iu.attr,
	&dev_attr_dt.attr,
	&dev_attr_qas.attr,
	&dev_attr_max_qas.attr,
	&dev_attr_wr_flow.attr,
	&dev_attr_rd_strm.attr,
	&dev_attr_rti.attr,
	&dev_attr_pcomp_en.attr,
	&dev_attr_hold_mcs.attr,
	&dev_attr_revalidate.attr,
	NULL
};

static struct attribute_group target_attribute_group = {
	.attrs = target_attributes,
	.is_visible = target_attribute_is_visible,
};

static int spi_target_configure(struct transport_container *tc,
				struct device *dev,
				struct device *cdev)
{
	struct kobject *kobj = &cdev->kobj;

	/* force an update based on parameters read from the device */
	sysfs_update_group(kobj, &target_attribute_group);

	return 0;
}

struct scsi_transport_template *
spi_attach_transport(struct spi_function_template *ft)
{
	struct spi_internal *i = kzalloc(sizeof(struct spi_internal),
					 GFP_KERNEL);

	if (unlikely(!i))
		return NULL;

	i->t.target_attrs.ac.class = &spi_transport_class.class;
	i->t.target_attrs.ac.grp = &target_attribute_group;
	i->t.target_attrs.ac.match = spi_target_match;
	transport_container_register(&i->t.target_attrs);
	i->t.target_size = sizeof(struct spi_transport_attrs);
	i->t.host_attrs.ac.class = &spi_host_class.class;
	i->t.host_attrs.ac.grp = &host_attribute_group;
	i->t.host_attrs.ac.match = spi_host_match;
	transport_container_register(&i->t.host_attrs);
	i->t.host_size = sizeof(struct spi_host_attrs);
	i->f = ft;

	return &i->t;
}
EXPORT_SYMBOL(spi_attach_transport);

void spi_release_transport(struct scsi_transport_template *t)
{
	struct spi_internal *i = to_spi_internal(t);

	transport_container_unregister(&i->t.target_attrs);
	transport_container_unregister(&i->t.host_attrs);

	kfree(i);
}
EXPORT_SYMBOL(spi_release_transport);

static __init int spi_transport_init(void)
{
	int error = scsi_dev_info_add_list(SCSI_DEVINFO_SPI,
					   "SCSI Parallel Transport Class");
	if (!error) {
		int i;

		for (i = 0; spi_static_device_list[i].vendor; i++)
			scsi_dev_info_list_add_keyed(1,	/* compatible */
						     spi_static_device_list[i].vendor,
						     spi_static_device_list[i].model,
						     NULL,
						     spi_static_device_list[i].flags,
						     SCSI_DEVINFO_SPI);
	}

	error = transport_class_register(&spi_transport_class);
	if (error)
		return error;
	error = anon_transport_class_register(&spi_device_class);
	return transport_class_register(&spi_host_class);
}

static void __exit spi_transport_exit(void)
{
	transport_class_unregister(&spi_transport_class);
	anon_transport_class_unregister(&spi_device_class);
	transport_class_unregister(&spi_host_class);
	scsi_dev_info_remove_list(SCSI_DEVINFO_SPI);
}

MODULE_AUTHOR("Martin Hicks");
MODULE_DESCRIPTION("SPI Transport Attributes");
MODULE_LICENSE("GPL");

module_init(spi_transport_init);
module_exit(spi_transport_exit);