aboutsummaryrefslogtreecommitdiff
path: root/drivers/scsi/libata-scsi.c
blob: 346eb36b1e31e0c5665269077e65ef4f11149644 (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
/*
 *  libata-scsi.c - helper library for ATA
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *    		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2004 Jeff Garzik
 *
 *
 *  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, 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; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from
 *  - http://www.t10.org/
 *  - http://www.t13.org/
 *
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
#include <linux/libata.h>
#include <asm/uaccess.h>

#include "libata.h"

typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, u8 *scsicmd);
static struct ata_device *
ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev);


/**
 *	ata_std_bios_param - generic bios head/sector/cylinder calculator used by sd.
 *	@sdev: SCSI device for which BIOS geometry is to be determined
 *	@bdev: block device associated with @sdev
 *	@capacity: capacity of SCSI device
 *	@geom: location to which geometry will be output
 *
 *	Generic bios head/sector/cylinder calculator
 *	used by sd. Most BIOSes nowadays expect a XXX/255/16  (CHS)
 *	mapping. Some situations may arise where the disk is not
 *	bootable if this is not used.
 *
 *	LOCKING:
 *	Defined by the SCSI layer.  We don't really care.
 *
 *	RETURNS:
 *	Zero.
 */
int ata_std_bios_param(struct scsi_device *sdev, struct block_device *bdev,
		       sector_t capacity, int geom[])
{
	geom[0] = 255;
	geom[1] = 63;
	sector_div(capacity, 255*63);
	geom[2] = capacity;

	return 0;
}

int ata_scsi_ioctl(struct scsi_device *scsidev, int cmd, void __user *arg)
{
	struct ata_port *ap;
	struct ata_device *dev;
	int val = -EINVAL, rc = -EINVAL;

	ap = (struct ata_port *) &scsidev->host->hostdata[0];
	if (!ap)
		goto out;

	dev = ata_scsi_find_dev(ap, scsidev);
	if (!dev) {
		rc = -ENODEV;
		goto out;
	}

	switch (cmd) {
	case ATA_IOC_GET_IO32:
		val = 0;
		if (copy_to_user(arg, &val, 1))
			return -EFAULT;
		return 0;

	case ATA_IOC_SET_IO32:
		val = (unsigned long) arg;
		if (val != 0)
			return -EINVAL;
		return 0;

	default:
		rc = -ENOTTY;
		break;
	}

out:
	return rc;
}

/**
 *	ata_scsi_qc_new - acquire new ata_queued_cmd reference
 *	@ap: ATA port to which the new command is attached
 *	@dev: ATA device to which the new command is attached
 *	@cmd: SCSI command that originated this ATA command
 *	@done: SCSI command completion function
 *
 *	Obtain a reference to an unused ata_queued_cmd structure,
 *	which is the basic libata structure representing a single
 *	ATA command sent to the hardware.
 *
 *	If a command was available, fill in the SCSI-specific
 *	portions of the structure with information on the
 *	current command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Command allocated, or %NULL if none available.
 */
struct ata_queued_cmd *ata_scsi_qc_new(struct ata_port *ap,
				       struct ata_device *dev,
				       struct scsi_cmnd *cmd,
				       void (*done)(struct scsi_cmnd *))
{
	struct ata_queued_cmd *qc;

	qc = ata_qc_new_init(ap, dev);
	if (qc) {
		qc->scsicmd = cmd;
		qc->scsidone = done;

		if (cmd->use_sg) {
			qc->sg = (struct scatterlist *) cmd->request_buffer;
			qc->n_elem = cmd->use_sg;
		} else {
			qc->sg = &qc->sgent;
			qc->n_elem = 1;
		}
	} else {
		cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
		done(cmd);
	}

	return qc;
}

/**
 *	ata_to_sense_error - convert ATA error to SCSI error
 *	@qc: Command that we are erroring out
 *	@drv_stat: value contained in ATA status register
 *
 *	Converts an ATA error into a SCSI error. While we are at it
 *	we decode and dump the ATA error for the user so that they
 *	have some idea what really happened at the non make-believe
 *	layer.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

void ata_to_sense_error(struct ata_queued_cmd *qc, u8 drv_stat)
{
	struct scsi_cmnd *cmd = qc->scsicmd;
	u8 err = 0;
	unsigned char *sb = cmd->sense_buffer;
	/* Based on the 3ware driver translation table */
	static unsigned char sense_table[][4] = {
		/* BBD|ECC|ID|MAR */
		{0xd1, 		ABORTED_COMMAND, 0x00, 0x00}, 	// Device busy                  Aborted command
		/* BBD|ECC|ID */
		{0xd0,  	ABORTED_COMMAND, 0x00, 0x00}, 	// Device busy                  Aborted command
		/* ECC|MC|MARK */
		{0x61, 		HARDWARE_ERROR, 0x00, 0x00}, 	// Device fault                 Hardware error
		/* ICRC|ABRT */		/* NB: ICRC & !ABRT is BBD */
		{0x84, 		ABORTED_COMMAND, 0x47, 0x00}, 	// Data CRC error               SCSI parity error
		/* MC|ID|ABRT|TRK0|MARK */
		{0x37, 		NOT_READY, 0x04, 0x00}, 	// Unit offline                 Not ready
		/* MCR|MARK */
		{0x09, 		NOT_READY, 0x04, 0x00}, 	// Unrecovered disk error       Not ready
		/*  Bad address mark */
		{0x01, 		MEDIUM_ERROR, 0x13, 0x00}, 	// Address mark not found       Address mark not found for data field
		/* TRK0 */
		{0x02, 		HARDWARE_ERROR, 0x00, 0x00}, 	// Track 0 not found		  Hardware error
		/* Abort & !ICRC */
		{0x04, 		ABORTED_COMMAND, 0x00, 0x00}, 	// Aborted command              Aborted command
		/* Media change request */
		{0x08, 		NOT_READY, 0x04, 0x00}, 	// Media change request	  FIXME: faking offline
		/* SRV */
		{0x10, 		ABORTED_COMMAND, 0x14, 0x00}, 	// ID not found                 Recorded entity not found
		/* Media change */
		{0x08,  	NOT_READY, 0x04, 0x00}, 	// Media change		  FIXME: faking offline
		/* ECC */
		{0x40, 		MEDIUM_ERROR, 0x11, 0x04}, 	// Uncorrectable ECC error      Unrecovered read error
		/* BBD - block marked bad */
		{0x80, 		MEDIUM_ERROR, 0x11, 0x04}, 	// Block marked bad		  Medium error, unrecovered read error
		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
	};
	static unsigned char stat_table[][4] = {
		/* Must be first because BUSY means no other bits valid */
		{0x80, 		ABORTED_COMMAND, 0x47, 0x00},	// Busy, fake parity for now
		{0x20, 		HARDWARE_ERROR,  0x00, 0x00}, 	// Device fault
		{0x08, 		ABORTED_COMMAND, 0x47, 0x00},	// Timed out in xfer, fake parity for now
		{0x04, 		RECOVERED_ERROR, 0x11, 0x00},	// Recovered ECC error	  Medium error, recovered
		{0xFF, 0xFF, 0xFF, 0xFF}, // END mark
	};
	int i = 0;

	cmd->result = SAM_STAT_CHECK_CONDITION;

	/*
	 *	Is this an error we can process/parse
	 */

	if(drv_stat & ATA_ERR)
		/* Read the err bits */
		err = ata_chk_err(qc->ap);

	/* Display the ATA level error info */

	printk(KERN_WARNING "ata%u: status=0x%02x { ", qc->ap->id, drv_stat);
	if(drv_stat & 0x80)
	{
		printk("Busy ");
		err = 0;	/* Data is not valid in this case */
	}
	else {
		if(drv_stat & 0x40)	printk("DriveReady ");
		if(drv_stat & 0x20)	printk("DeviceFault ");
		if(drv_stat & 0x10)	printk("SeekComplete ");
		if(drv_stat & 0x08)	printk("DataRequest ");
		if(drv_stat & 0x04)	printk("CorrectedError ");
		if(drv_stat & 0x02)	printk("Index ");
		if(drv_stat & 0x01)	printk("Error ");
	}
	printk("}\n");

	if(err)
	{
		printk(KERN_WARNING "ata%u: error=0x%02x { ", qc->ap->id, err);
		if(err & 0x04)		printk("DriveStatusError ");
		if(err & 0x80)
		{
			if(err & 0x04)
				printk("BadCRC ");
			else
				printk("Sector ");
		}
		if(err & 0x40)		printk("UncorrectableError ");
		if(err & 0x10)		printk("SectorIdNotFound ");
		if(err & 0x02)		printk("TrackZeroNotFound ");
		if(err & 0x01)		printk("AddrMarkNotFound ");
		printk("}\n");

		/* Should we dump sector info here too ?? */
	}


	/* Look for err */
	while(sense_table[i][0] != 0xFF)
	{
		/* Look for best matches first */
		if((sense_table[i][0] & err) == sense_table[i][0])
		{
			sb[0] = 0x70;
			sb[2] = sense_table[i][1];
			sb[7] = 0x0a;
			sb[12] = sense_table[i][2];
			sb[13] = sense_table[i][3];
			return;
		}
		i++;
	}
	/* No immediate match */
	if(err)
		printk(KERN_DEBUG "ata%u: no sense translation for 0x%02x\n", qc->ap->id, err);

	i = 0;
	/* Fall back to interpreting status bits */
	while(stat_table[i][0] != 0xFF)
	{
		if(stat_table[i][0] & drv_stat)
		{
			sb[0] = 0x70;
			sb[2] = stat_table[i][1];
			sb[7] = 0x0a;
			sb[12] = stat_table[i][2];
			sb[13] = stat_table[i][3];
			return;
		}
		i++;
	}
	/* No error ?? */
	printk(KERN_ERR "ata%u: called with no error (%02X)!\n", qc->ap->id, drv_stat);
	/* additional-sense-code[-qualifier] */

	sb[0] = 0x70;
	sb[2] = MEDIUM_ERROR;
	sb[7] = 0x0A;
	if (cmd->sc_data_direction == DMA_FROM_DEVICE) {
		sb[12] = 0x11; /* "unrecovered read error" */
		sb[13] = 0x04;
	} else {
		sb[12] = 0x0C; /* "write error -             */
		sb[13] = 0x02; /*  auto-reallocation failed" */
	}
}

/**
 *	ata_scsi_slave_config - Set SCSI device attributes
 *	@sdev: SCSI device to examine
 *
 *	This is called before we actually start reading
 *	and writing to the device, to configure certain
 *	SCSI mid-layer behaviors.
 *
 *	LOCKING:
 *	Defined by SCSI layer.  We don't really care.
 */

int ata_scsi_slave_config(struct scsi_device *sdev)
{
	sdev->use_10_for_rw = 1;
	sdev->use_10_for_ms = 1;

	blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);

	if (sdev->id < ATA_MAX_DEVICES) {
		struct ata_port *ap;
		struct ata_device *dev;

		ap = (struct ata_port *) &sdev->host->hostdata[0];
		dev = &ap->device[sdev->id];

		/* TODO: 1024 is an arbitrary number, not the
		 * hardware maximum.  This should be increased to
		 * 65534 when Jens Axboe's patch for dynamically
		 * determining max_sectors is merged.
		 */
		if ((dev->flags & ATA_DFLAG_LBA48) &&
		    ((dev->flags & ATA_DFLAG_LOCK_SECTORS) == 0)) {
			/*
			 * do not overwrite sdev->host->max_sectors, since
			 * other drives on this host may not support LBA48
			 */
			blk_queue_max_sectors(sdev->request_queue, 2048);
		}
	}

	return 0;	/* scsi layer doesn't check return value, sigh */
}

/**
 *	ata_scsi_error - SCSI layer error handler callback
 *	@host: SCSI host on which error occurred
 *
 *	Handles SCSI-layer-thrown error events.
 *
 *	LOCKING:
 *	Inherited from SCSI layer (none, can sleep)
 *
 *	RETURNS:
 *	Zero.
 */

int ata_scsi_error(struct Scsi_Host *host)
{
	struct ata_port *ap;

	DPRINTK("ENTER\n");

	ap = (struct ata_port *) &host->hostdata[0];
	ap->ops->eng_timeout(ap);

	/* TODO: this is per-command; when queueing is supported
	 * this code will either change or move to a more
	 * appropriate place
	 */
	host->host_failed--;
	INIT_LIST_HEAD(&host->eh_cmd_q);

	DPRINTK("EXIT\n");
	return 0;
}

/**
 *	ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
 *	@qc: Storage for translated ATA taskfile
 *	@scsicmd: SCSI command to translate
 *
 *	Sets up an ATA taskfile to issue STANDBY (to stop) or READ VERIFY
 *	(to start). Perhaps these commands should be preceded by
 *	CHECK POWER MODE to see what power mode the device is already in.
 *	[See SAT revision 5 at www.t10.org]
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc,
					     u8 *scsicmd)
{
	struct ata_taskfile *tf = &qc->tf;

	tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
	tf->protocol = ATA_PROT_NODATA;
	if (scsicmd[1] & 0x1) {
		;	/* ignore IMMED bit, violates sat-r05 */
	}
	if (scsicmd[4] & 0x2)
		return 1;	/* LOEJ bit set not supported */
	if (((scsicmd[4] >> 4) & 0xf) != 0)
		return 1;	/* power conditions not supported */
	if (scsicmd[4] & 0x1) {
		tf->nsect = 1;	/* 1 sector, lba=0 */
		tf->lbah = 0x0;
		tf->lbam = 0x0;
		tf->lbal = 0x0;
		tf->device |= ATA_LBA;
		tf->command = ATA_CMD_VERIFY;	/* READ VERIFY */
	} else {
		tf->nsect = 0;	/* time period value (0 implies now) */
		tf->command = ATA_CMD_STANDBY;
		/* Consider: ATA STANDBY IMMEDIATE command */
	}
	/*
	 * Standby and Idle condition timers could be implemented but that
	 * would require libata to implement the Power condition mode page
	 * and allow the user to change it. Changing mode pages requires
	 * MODE SELECT to be implemented.
	 */

	return 0;
}


/**
 *	ata_scsi_flush_xlat - Translate SCSI SYNCHRONIZE CACHE command
 *	@qc: Storage for translated ATA taskfile
 *	@scsicmd: SCSI command to translate (ignored)
 *
 *	Sets up an ATA taskfile to issue FLUSH CACHE or
 *	FLUSH CACHE EXT.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
{
	struct ata_taskfile *tf = &qc->tf;

	tf->flags |= ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;

	if ((tf->flags & ATA_TFLAG_LBA48) &&
	    (ata_id_has_flush_ext(qc->dev->id)))
		tf->command = ATA_CMD_FLUSH_EXT;
	else
		tf->command = ATA_CMD_FLUSH;

	return 0;
}

/**
 *	ata_scsi_verify_xlat - Translate SCSI VERIFY command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *	@scsicmd: SCSI command to translate
 *
 *	Converts SCSI VERIFY command to an ATA READ VERIFY command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
{
	struct ata_taskfile *tf = &qc->tf;
	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;
	u64 dev_sectors = qc->dev->n_sectors;
	u64 sect = 0;
	u32 n_sect = 0;

	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;
	tf->device |= ATA_LBA;

	if (scsicmd[0] == VERIFY) {
		sect |= ((u64)scsicmd[2]) << 24;
		sect |= ((u64)scsicmd[3]) << 16;
		sect |= ((u64)scsicmd[4]) << 8;
		sect |= ((u64)scsicmd[5]);

		n_sect |= ((u32)scsicmd[7]) << 8;
		n_sect |= ((u32)scsicmd[8]);
	}

	else if (scsicmd[0] == VERIFY_16) {
		sect |= ((u64)scsicmd[2]) << 56;
		sect |= ((u64)scsicmd[3]) << 48;
		sect |= ((u64)scsicmd[4]) << 40;
		sect |= ((u64)scsicmd[5]) << 32;
		sect |= ((u64)scsicmd[6]) << 24;
		sect |= ((u64)scsicmd[7]) << 16;
		sect |= ((u64)scsicmd[8]) << 8;
		sect |= ((u64)scsicmd[9]);

		n_sect |= ((u32)scsicmd[10]) << 24;
		n_sect |= ((u32)scsicmd[11]) << 16;
		n_sect |= ((u32)scsicmd[12]) << 8;
		n_sect |= ((u32)scsicmd[13]);
	}

	else
		return 1;

	if (!n_sect)
		return 1;
	if (sect >= dev_sectors)
		return 1;
	if ((sect + n_sect) > dev_sectors)
		return 1;
	if (lba48) {
		if (n_sect > (64 * 1024))
			return 1;
	} else {
		if (n_sect > 256)
			return 1;
	}

	if (lba48) {
		tf->command = ATA_CMD_VERIFY_EXT;

		tf->hob_nsect = (n_sect >> 8) & 0xff;

		tf->hob_lbah = (sect >> 40) & 0xff;
		tf->hob_lbam = (sect >> 32) & 0xff;
		tf->hob_lbal = (sect >> 24) & 0xff;
	} else {
		tf->command = ATA_CMD_VERIFY;

		tf->device |= (sect >> 24) & 0xf;
	}

	tf->nsect = n_sect & 0xff;

	tf->lbah = (sect >> 16) & 0xff;
	tf->lbam = (sect >> 8) & 0xff;
	tf->lbal = sect & 0xff;

	return 0;
}

/**
 *	ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *	@scsicmd: SCSI command to translate
 *
 *	Converts any of six SCSI read/write commands into the
 *	ATA counterpart, including starting sector (LBA),
 *	sector count, and taking into account the device's LBA48
 *	support.
 *
 *	Commands %READ_6, %READ_10, %READ_16, %WRITE_6, %WRITE_10, and
 *	%WRITE_16 are currently supported.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */

static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
{
	struct ata_taskfile *tf = &qc->tf;
	unsigned int lba48 = tf->flags & ATA_TFLAG_LBA48;

	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->protocol = qc->dev->xfer_protocol;
	tf->device |= ATA_LBA;

	if (scsicmd[0] == READ_10 || scsicmd[0] == READ_6 ||
	    scsicmd[0] == READ_16) {
		tf->command = qc->dev->read_cmd;
	} else {
		tf->command = qc->dev->write_cmd;
		tf->flags |= ATA_TFLAG_WRITE;
	}

	if (scsicmd[0] == READ_10 || scsicmd[0] == WRITE_10) {
		if (lba48) {
			tf->hob_nsect = scsicmd[7];
			tf->hob_lbal = scsicmd[2];

			qc->nsect = ((unsigned int)scsicmd[7] << 8) |
					scsicmd[8];
		} else {
			/* if we don't support LBA48 addressing, the request
			 * -may- be too large. */
			if ((scsicmd[2] & 0xf0) || scsicmd[7])
				return 1;

			/* stores LBA27:24 in lower 4 bits of device reg */
			tf->device |= scsicmd[2];

			qc->nsect = scsicmd[8];
		}

		tf->nsect = scsicmd[8];
		tf->lbal = scsicmd[5];
		tf->lbam = scsicmd[4];
		tf->lbah = scsicmd[3];

		VPRINTK("ten-byte command\n");
		if (qc->nsect == 0) /* we don't support length==0 cmds */
			return 1;
		return 0;
	}

	if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
		qc->nsect = tf->nsect = scsicmd[4];
		if (!qc->nsect) {
			qc->nsect = 256;
			if (lba48)
				tf->hob_nsect = 1;
		}

		tf->lbal = scsicmd[3];
		tf->lbam = scsicmd[2];
		tf->lbah = scsicmd[1] & 0x1f; /* mask out reserved bits */

		VPRINTK("six-byte command\n");
		return 0;
	}

	if (scsicmd[0] == READ_16 || scsicmd[0] == WRITE_16) {
		/* rule out impossible LBAs and sector counts */
		if (scsicmd[2] || scsicmd[3] || scsicmd[10] || scsicmd[11])
			return 1;

		if (lba48) {
			tf->hob_nsect = scsicmd[12];
			tf->hob_lbal = scsicmd[6];
			tf->hob_lbam = scsicmd[5];
			tf->hob_lbah = scsicmd[4];

			qc->nsect = ((unsigned int)scsicmd[12] << 8) |
					scsicmd[13];
		} else {
			/* once again, filter out impossible non-zero values */
			if (scsicmd[4] || scsicmd[5] || scsicmd[12] ||
			    (scsicmd[6] & 0xf0))
				return 1;

			/* stores LBA27:24 in lower 4 bits of device reg */
			tf->device |= scsicmd[6];

			qc->nsect = scsicmd[13];
		}

		tf->nsect = scsicmd[13];
		tf->lbal = scsicmd[9];
		tf->lbam = scsicmd[8];
		tf->lbah = scsicmd[7];

		VPRINTK("sixteen-byte command\n");
		if (qc->nsect == 0) /* we don't support length==0 cmds */
			return 1;
		return 0;
	}

	DPRINTK("no-byte command\n");
	return 1;
}

static int ata_scsi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
{
	struct scsi_cmnd *cmd = qc->scsicmd;

	if (unlikely(drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ)))
		ata_to_sense_error(qc, drv_stat);
	else
		cmd->result = SAM_STAT_GOOD;

	qc->scsidone(cmd);

	return 0;
}

/**
 *	ata_scsi_translate - Translate then issue SCSI command to ATA device
 *	@ap: ATA port to which the command is addressed
 *	@dev: ATA device to which the command is addressed
 *	@cmd: SCSI command to execute
 *	@done: SCSI command completion function
 *	@xlat_func: Actor which translates @cmd to an ATA taskfile
 *
 *	Our ->queuecommand() function has decided that the SCSI
 *	command issued can be directly translated into an ATA
 *	command, rather than handled internally.
 *
 *	This function sets up an ata_queued_cmd structure for the
 *	SCSI command, and sends that ata_queued_cmd to the hardware.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

static void ata_scsi_translate(struct ata_port *ap, struct ata_device *dev,
			      struct scsi_cmnd *cmd,
			      void (*done)(struct scsi_cmnd *),
			      ata_xlat_func_t xlat_func)
{
	struct ata_queued_cmd *qc;
	u8 *scsicmd = cmd->cmnd;

	VPRINTK("ENTER\n");

	qc = ata_scsi_qc_new(ap, dev, cmd, done);
	if (!qc)
		return;

	/* data is present; dma-map it */
	if (cmd->sc_data_direction == DMA_FROM_DEVICE ||
	    cmd->sc_data_direction == DMA_TO_DEVICE) {
		if (unlikely(cmd->request_bufflen < 1)) {
			printk(KERN_WARNING "ata%u(%u): WARNING: zero len r/w req\n",
			       ap->id, dev->devno);
			goto err_out;
		}

		if (cmd->use_sg)
			ata_sg_init(qc, cmd->request_buffer, cmd->use_sg);
		else
			ata_sg_init_one(qc, cmd->request_buffer,
					cmd->request_bufflen);

		qc->dma_dir = cmd->sc_data_direction;
	}

	qc->complete_fn = ata_scsi_qc_complete;

	if (xlat_func(qc, scsicmd))
		goto err_out;

	/* select device, send command to hardware */
	if (ata_qc_issue(qc))
		goto err_out;

	VPRINTK("EXIT\n");
	return;

err_out:
	ata_qc_free(qc);
	ata_bad_cdb(cmd, done);
	DPRINTK("EXIT - badcmd\n");
}

/**
 *	ata_scsi_rbuf_get - Map response buffer.
 *	@cmd: SCSI command containing buffer to be mapped.
 *	@buf_out: Pointer to mapped area.
 *
 *	Maps buffer contained within SCSI command @cmd.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Length of response buffer.
 */

static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out)
{
	u8 *buf;
	unsigned int buflen;

	if (cmd->use_sg) {
		struct scatterlist *sg;

		sg = (struct scatterlist *) cmd->request_buffer;
		buf = kmap_atomic(sg->page, KM_USER0) + sg->offset;
		buflen = sg->length;
	} else {
		buf = cmd->request_buffer;
		buflen = cmd->request_bufflen;
	}

	*buf_out = buf;
	return buflen;
}

/**
 *	ata_scsi_rbuf_put - Unmap response buffer.
 *	@cmd: SCSI command containing buffer to be unmapped.
 *	@buf: buffer to unmap
 *
 *	Unmaps response buffer contained within @cmd.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

static inline void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, u8 *buf)
{
	if (cmd->use_sg) {
		struct scatterlist *sg;

		sg = (struct scatterlist *) cmd->request_buffer;
		kunmap_atomic(buf - sg->offset, KM_USER0);
	}
}

/**
 *	ata_scsi_rbuf_fill - wrapper for SCSI command simulators
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@actor: Callback hook for desired SCSI command simulator
 *
 *	Takes care of the hard work of simulating a SCSI command...
 *	Mapping the response buffer, calling the command's handler,
 *	and handling the handler's return value.  This return value
 *	indicates whether the handler wishes the SCSI command to be
 *	completed successfully, or not.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
		        unsigned int (*actor) (struct ata_scsi_args *args,
			     		   u8 *rbuf, unsigned int buflen))
{
	u8 *rbuf;
	unsigned int buflen, rc;
	struct scsi_cmnd *cmd = args->cmd;

	buflen = ata_scsi_rbuf_get(cmd, &rbuf);
	memset(rbuf, 0, buflen);
	rc = actor(args, rbuf, buflen);
	ata_scsi_rbuf_put(cmd, rbuf);

	if (rc)
		ata_bad_cdb(cmd, args->done);
	else {
		cmd->result = SAM_STAT_GOOD;
		args->done(cmd);
	}
}

/**
 *	ata_scsiop_inq_std - Simulate INQUIRY command
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Returns standard device identification data associated
 *	with non-EVPD INQUIRY command output.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
			       unsigned int buflen)
{
	u8 hdr[] = {
		TYPE_DISK,
		0,
		0x5,	/* claim SPC-3 version compatibility */
		2,
		95 - 4
	};

	/* set scsi removeable (RMB) bit per ata bit */
	if (ata_id_removeable(args->id))
		hdr[1] |= (1 << 7);

	VPRINTK("ENTER\n");

	memcpy(rbuf, hdr, sizeof(hdr));

	if (buflen > 35) {
		memcpy(&rbuf[8], "ATA     ", 8);
		ata_dev_id_string(args->id, &rbuf[16], ATA_ID_PROD_OFS, 16);
		ata_dev_id_string(args->id, &rbuf[32], ATA_ID_FW_REV_OFS, 4);
		if (rbuf[32] == 0 || rbuf[32] == ' ')
			memcpy(&rbuf[32], "n/a ", 4);
	}

	if (buflen > 63) {
		const u8 versions[] = {
			0x60,	/* SAM-3 (no version claimed) */

			0x03,
			0x20,	/* SBC-2 (no version claimed) */

			0x02,
			0x60	/* SPC-3 (no version claimed) */
		};

		memcpy(rbuf + 59, versions, sizeof(versions));
	}

	return 0;
}

/**
 *	ata_scsiop_inq_00 - Simulate INQUIRY EVPD page 0, list of pages
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Returns list of inquiry EVPD pages available.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf,
			      unsigned int buflen)
{
	const u8 pages[] = {
		0x00,	/* page 0x00, this page */
		0x80,	/* page 0x80, unit serial no page */
		0x83	/* page 0x83, device ident page */
	};
	rbuf[3] = sizeof(pages);	/* number of supported EVPD pages */

	if (buflen > 6)
		memcpy(rbuf + 4, pages, sizeof(pages));

	return 0;
}

/**
 *	ata_scsiop_inq_80 - Simulate INQUIRY EVPD page 80, device serial number
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Returns ATA device serial number.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_80(struct ata_scsi_args *args, u8 *rbuf,
			      unsigned int buflen)
{
	const u8 hdr[] = {
		0,
		0x80,			/* this page code */
		0,
		ATA_SERNO_LEN,		/* page len */
	};
	memcpy(rbuf, hdr, sizeof(hdr));

	if (buflen > (ATA_SERNO_LEN + 4 - 1))
		ata_dev_id_string(args->id, (unsigned char *) &rbuf[4],
				  ATA_ID_SERNO_OFS, ATA_SERNO_LEN);

	return 0;
}

static const char *inq_83_str = "Linux ATA-SCSI simulator";

/**
 *	ata_scsiop_inq_83 - Simulate INQUIRY EVPD page 83, device identity
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Returns device identification.  Currently hardcoded to
 *	return "Linux ATA-SCSI simulator".
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf,
			      unsigned int buflen)
{
	rbuf[1] = 0x83;			/* this page code */
	rbuf[3] = 4 + strlen(inq_83_str);	/* page len */

	/* our one and only identification descriptor (vendor-specific) */
	if (buflen > (strlen(inq_83_str) + 4 + 4 - 1)) {
		rbuf[4 + 0] = 2;	/* code set: ASCII */
		rbuf[4 + 3] = strlen(inq_83_str);
		memcpy(rbuf + 4 + 4, inq_83_str, strlen(inq_83_str));
	}

	return 0;
}

/**
 *	ata_scsiop_noop - Command handler that simply returns success.
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	No operation.  Simply returns success to caller, to indicate
 *	that the caller should successfully complete this SCSI command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_noop(struct ata_scsi_args *args, u8 *rbuf,
			    unsigned int buflen)
{
	VPRINTK("ENTER\n");
	return 0;
}

/**
 *	ata_msense_push - Push data onto MODE SENSE data output buffer
 *	@ptr_io: (input/output) Location to store more output data
 *	@last: End of output data buffer
 *	@buf: Pointer to BLOB being added to output buffer
 *	@buflen: Length of BLOB
 *
 *	Store MODE SENSE data on an output buffer.
 *
 *	LOCKING:
 *	None.
 */

static void ata_msense_push(u8 **ptr_io, const u8 *last,
			    const u8 *buf, unsigned int buflen)
{
	u8 *ptr = *ptr_io;

	if ((ptr + buflen - 1) > last)
		return;

	memcpy(ptr, buf, buflen);

	ptr += buflen;

	*ptr_io = ptr;
}

/**
 *	ata_msense_caching - Simulate MODE SENSE caching info page
 *	@id: device IDENTIFY data
 *	@ptr_io: (input/output) Location to store more output data
 *	@last: End of output data buffer
 *
 *	Generate a caching info page, which conditionally indicates
 *	write caching to the SCSI layer, depending on device
 *	capabilities.
 *
 *	LOCKING:
 *	None.
 */

static unsigned int ata_msense_caching(u16 *id, u8 **ptr_io,
				       const u8 *last)
{
	u8 page[] = {
		0x8,				/* page code */
		0x12,				/* page length */
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 10 zeroes */
		0, 0, 0, 0, 0, 0, 0, 0		/* 8 zeroes */
	};

	if (ata_id_wcache_enabled(id))
		page[2] |= (1 << 2);	/* write cache enable */
	if (!ata_id_rahead_enabled(id))
		page[12] |= (1 << 5);	/* disable read ahead */

	ata_msense_push(ptr_io, last, page, sizeof(page));
	return sizeof(page);
}

/**
 *	ata_msense_ctl_mode - Simulate MODE SENSE control mode page
 *	@dev: Device associated with this MODE SENSE command
 *	@ptr_io: (input/output) Location to store more output data
 *	@last: End of output data buffer
 *
 *	Generate a generic MODE SENSE control mode page.
 *
 *	LOCKING:
 *	None.
 */

static unsigned int ata_msense_ctl_mode(u8 **ptr_io, const u8 *last)
{
	const u8 page[] = {0xa, 0xa, 6, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 30};

	/* byte 2: set the descriptor format sense data bit (bit 2)
	 * since we need to support returning this format for SAT
	 * commands and any SCSI commands against a 48b LBA device.
	 */

	ata_msense_push(ptr_io, last, page, sizeof(page));
	return sizeof(page);
}

/**
 *	ata_msense_rw_recovery - Simulate MODE SENSE r/w error recovery page
 *	@dev: Device associated with this MODE SENSE command
 *	@ptr_io: (input/output) Location to store more output data
 *	@last: End of output data buffer
 *
 *	Generate a generic MODE SENSE r/w error recovery page.
 *
 *	LOCKING:
 *	None.
 */

static unsigned int ata_msense_rw_recovery(u8 **ptr_io, const u8 *last)
{
	const u8 page[] = {
		0x1,			  /* page code */
		0xa,			  /* page length */
		(1 << 7) | (1 << 6),	  /* note auto r/w reallocation */
		0, 0, 0, 0, 0, 0, 0, 0, 0 /* 9 zeroes */
	};

	ata_msense_push(ptr_io, last, page, sizeof(page));
	return sizeof(page);
}

/**
 *	ata_scsiop_mode_sense - Simulate MODE SENSE 6, 10 commands
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Simulate MODE SENSE commands.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf,
				  unsigned int buflen)
{
	u8 *scsicmd = args->cmd->cmnd, *p, *last;
	unsigned int page_control, six_byte, output_len;

	VPRINTK("ENTER\n");

	six_byte = (scsicmd[0] == MODE_SENSE);

	/* we only support saved and current values (which we treat
	 * in the same manner)
	 */
	page_control = scsicmd[2] >> 6;
	if ((page_control != 0) && (page_control != 3))
		return 1;

	if (six_byte)
		output_len = 4;
	else
		output_len = 8;

	p = rbuf + output_len;
	last = rbuf + buflen - 1;

	switch(scsicmd[2] & 0x3f) {
	case 0x01:		/* r/w error recovery */
		output_len += ata_msense_rw_recovery(&p, last);
		break;

	case 0x08:		/* caching */
		output_len += ata_msense_caching(args->id, &p, last);
		break;

	case 0x0a: {		/* control mode */
		output_len += ata_msense_ctl_mode(&p, last);
		break;
		}

	case 0x3f:		/* all pages */
		output_len += ata_msense_rw_recovery(&p, last);
		output_len += ata_msense_caching(args->id, &p, last);
		output_len += ata_msense_ctl_mode(&p, last);
		break;

	default:		/* invalid page code */
		return 1;
	}

	if (six_byte) {
		output_len--;
		rbuf[0] = output_len;
	} else {
		output_len -= 2;
		rbuf[0] = output_len >> 8;
		rbuf[1] = output_len;
	}

	return 0;
}

/**
 *	ata_scsiop_read_cap - Simulate READ CAPACITY[ 16] commands
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Simulate READ CAPACITY commands.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_read_cap(struct ata_scsi_args *args, u8 *rbuf,
			        unsigned int buflen)
{
	u64 n_sectors;
	u32 tmp;

	VPRINTK("ENTER\n");

	if (ata_id_has_lba48(args->id))
		n_sectors = ata_id_u64(args->id, 100);
	else
		n_sectors = ata_id_u32(args->id, 60);
	n_sectors--;		/* ATA TotalUserSectors - 1 */

	if (args->cmd->cmnd[0] == READ_CAPACITY) {
		if( n_sectors >= 0xffffffffULL )
			tmp = 0xffffffff ;  /* Return max count on overflow */
		else
			tmp = n_sectors ;

		/* sector count, 32-bit */
		rbuf[0] = tmp >> (8 * 3);
		rbuf[1] = tmp >> (8 * 2);
		rbuf[2] = tmp >> (8 * 1);
		rbuf[3] = tmp;

		/* sector size */
		tmp = ATA_SECT_SIZE;
		rbuf[6] = tmp >> 8;
		rbuf[7] = tmp;

	} else {
		/* sector count, 64-bit */
		tmp = n_sectors >> (8 * 4);
		rbuf[2] = tmp >> (8 * 3);
		rbuf[3] = tmp >> (8 * 2);
		rbuf[4] = tmp >> (8 * 1);
		rbuf[5] = tmp;
		tmp = n_sectors;
		rbuf[6] = tmp >> (8 * 3);
		rbuf[7] = tmp >> (8 * 2);
		rbuf[8] = tmp >> (8 * 1);
		rbuf[9] = tmp;

		/* sector size */
		tmp = ATA_SECT_SIZE;
		rbuf[12] = tmp >> 8;
		rbuf[13] = tmp;
	}

	return 0;
}

/**
 *	ata_scsiop_report_luns - Simulate REPORT LUNS command
 *	@args: device IDENTIFY data / SCSI command of interest.
 *	@rbuf: Response buffer, to which simulated SCSI cmd output is sent.
 *	@buflen: Response buffer length.
 *
 *	Simulate REPORT LUNS command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

unsigned int ata_scsiop_report_luns(struct ata_scsi_args *args, u8 *rbuf,
				   unsigned int buflen)
{
	VPRINTK("ENTER\n");
	rbuf[3] = 8;	/* just one lun, LUN 0, size 8 bytes */

	return 0;
}

/**
 *	ata_scsi_badcmd - End a SCSI request with an error
 *	@cmd: SCSI request to be handled
 *	@done: SCSI command completion function
 *	@asc: SCSI-defined additional sense code
 *	@ascq: SCSI-defined additional sense code qualifier
 *
 *	Helper function that completes a SCSI command with
 *	%SAM_STAT_CHECK_CONDITION, with a sense key %ILLEGAL_REQUEST
 *	and the specified additional sense codes.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8 asc, u8 ascq)
{
	DPRINTK("ENTER\n");
	cmd->result = SAM_STAT_CHECK_CONDITION;

	cmd->sense_buffer[0] = 0x70;
	cmd->sense_buffer[2] = ILLEGAL_REQUEST;
	cmd->sense_buffer[7] = 14 - 8;	/* addnl. sense len. FIXME: correct? */
	cmd->sense_buffer[12] = asc;
	cmd->sense_buffer[13] = ascq;

	done(cmd);
}

static int atapi_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
{
	struct scsi_cmnd *cmd = qc->scsicmd;

	if (unlikely(drv_stat & (ATA_ERR | ATA_BUSY | ATA_DRQ))) {
		DPRINTK("request check condition\n");

		cmd->result = SAM_STAT_CHECK_CONDITION;

		qc->scsidone(cmd);

		return 1;
	} else {
		u8 *scsicmd = cmd->cmnd;

		if (scsicmd[0] == INQUIRY) {
			u8 *buf = NULL;
			unsigned int buflen;

			buflen = ata_scsi_rbuf_get(cmd, &buf);
			buf[2] = 0x5;
			buf[3] = (buf[3] & 0xf0) | 2;
			ata_scsi_rbuf_put(cmd, buf);
		}
		cmd->result = SAM_STAT_GOOD;
	}

	qc->scsidone(cmd);

	return 0;
}
/**
 *	atapi_xlat - Initialize PACKET taskfile
 *	@qc: command structure to be initialized
 *	@scsicmd: SCSI CDB associated with this PACKET command
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on failure.
 */

static unsigned int atapi_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
{
	struct scsi_cmnd *cmd = qc->scsicmd;
	struct ata_device *dev = qc->dev;
	int using_pio = (dev->flags & ATA_DFLAG_PIO);
	int nodata = (cmd->sc_data_direction == DMA_NONE);

	if (!using_pio)
		/* Check whether ATAPI DMA is safe */
		if (ata_check_atapi_dma(qc))
			using_pio = 1;

	memcpy(&qc->cdb, scsicmd, qc->ap->cdb_len);

	qc->complete_fn = atapi_qc_complete;

	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	if (cmd->sc_data_direction == DMA_TO_DEVICE) {
		qc->tf.flags |= ATA_TFLAG_WRITE;
		DPRINTK("direction: write\n");
	}

	qc->tf.command = ATA_CMD_PACKET;

	/* no data, or PIO data xfer */
	if (using_pio || nodata) {
		if (nodata)
			qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
		else
			qc->tf.protocol = ATA_PROT_ATAPI;
		qc->tf.lbam = (8 * 1024) & 0xff;
		qc->tf.lbah = (8 * 1024) >> 8;
	}

	/* DMA data xfer */
	else {
		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
		qc->tf.feature |= ATAPI_PKT_DMA;

#ifdef ATAPI_ENABLE_DMADIR
		/* some SATA bridges need us to indicate data xfer direction */
		if (cmd->sc_data_direction != DMA_TO_DEVICE)
			qc->tf.feature |= ATAPI_DMADIR;
#endif
	}

	qc->nbytes = cmd->bufflen;

	return 0;
}

/**
 *	ata_scsi_find_dev - lookup ata_device from scsi_cmnd
 *	@ap: ATA port to which the device is attached
 *	@scsidev: SCSI device from which we derive the ATA device
 *
 *	Given various information provided in struct scsi_cmnd,
 *	map that onto an ATA bus, and using that mapping
 *	determine which ata_device is associated with the
 *	SCSI command to be sent.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Associated ATA device, or %NULL if not found.
 */

static struct ata_device *
ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev)
{
	struct ata_device *dev;

	/* skip commands not addressed to targets we simulate */
	if (likely(scsidev->id < ATA_MAX_DEVICES))
		dev = &ap->device[scsidev->id];
	else
		return NULL;

	if (unlikely((scsidev->channel != 0) ||
		     (scsidev->lun != 0)))
		return NULL;

	if (unlikely(!ata_dev_present(dev)))
		return NULL;

#ifndef ATA_ENABLE_ATAPI
	if (unlikely(dev->class == ATA_DEV_ATAPI))
		return NULL;
#endif

	return dev;
}

/**
 *	ata_get_xlat_func - check if SCSI to ATA translation is possible
 *	@dev: ATA device
 *	@cmd: SCSI command opcode to consider
 *
 *	Look up the SCSI command given, and determine whether the
 *	SCSI command is to be translated or simulated.
 *
 *	RETURNS:
 *	Pointer to translation function if possible, %NULL if not.
 */

static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
{
	switch (cmd) {
	case READ_6:
	case READ_10:
	case READ_16:

	case WRITE_6:
	case WRITE_10:
	case WRITE_16:
		return ata_scsi_rw_xlat;

	case SYNCHRONIZE_CACHE:
		if (ata_try_flush_cache(dev))
			return ata_scsi_flush_xlat;
		break;

	case VERIFY:
	case VERIFY_16:
		return ata_scsi_verify_xlat;
	case START_STOP:
		return ata_scsi_start_stop_xlat;
	}

	return NULL;
}

/**
 *	ata_scsi_dump_cdb - dump SCSI command contents to dmesg
 *	@ap: ATA port to which the command was being sent
 *	@cmd: SCSI command to dump
 *
 *	Prints the contents of a SCSI command via printk().
 */

static inline void ata_scsi_dump_cdb(struct ata_port *ap,
				     struct scsi_cmnd *cmd)
{
#ifdef ATA_DEBUG
	struct scsi_device *scsidev = cmd->device;
	u8 *scsicmd = cmd->cmnd;

	DPRINTK("CDB (%u:%d,%d,%d) %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
		ap->id,
		scsidev->channel, scsidev->id, scsidev->lun,
		scsicmd[0], scsicmd[1], scsicmd[2], scsicmd[3],
		scsicmd[4], scsicmd[5], scsicmd[6], scsicmd[7],
		scsicmd[8]);
#endif
}

/**
 *	ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
 *	@cmd: SCSI command to be sent
 *	@done: Completion function, called when command is complete
 *
 *	In some cases, this function translates SCSI commands into
 *	ATA taskfiles, and queues the taskfiles to be sent to
 *	hardware.  In other cases, this function simulates a
 *	SCSI device by evaluating and responding to certain
 *	SCSI commands.  This creates the overall effect of
 *	ATA and ATAPI devices appearing as SCSI devices.
 *
 *	LOCKING:
 *	Releases scsi-layer-held lock, and obtains host_set lock.
 *
 *	RETURNS:
 *	Zero.
 */

int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
	struct ata_port *ap;
	struct ata_device *dev;
	struct scsi_device *scsidev = cmd->device;

	ap = (struct ata_port *) &scsidev->host->hostdata[0];

	ata_scsi_dump_cdb(ap, cmd);

	dev = ata_scsi_find_dev(ap, scsidev);
	if (unlikely(!dev)) {
		cmd->result = (DID_BAD_TARGET << 16);
		done(cmd);
		goto out_unlock;
	}

	if (dev->class == ATA_DEV_ATA) {
		ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
							      cmd->cmnd[0]);

		if (xlat_func)
			ata_scsi_translate(ap, dev, cmd, done, xlat_func);
		else
			ata_scsi_simulate(dev->id, cmd, done);
	} else
		ata_scsi_translate(ap, dev, cmd, done, atapi_xlat);

out_unlock:
	return 0;
}

/**
 *	ata_scsi_simulate - simulate SCSI command on ATA device
 *	@id: current IDENTIFY data for target device.
 *	@cmd: SCSI command being sent to device.
 *	@done: SCSI command completion function.
 *
 *	Interprets and directly executes a select list of SCSI commands
 *	that can be handled internally.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

void ata_scsi_simulate(u16 *id,
		      struct scsi_cmnd *cmd,
		      void (*done)(struct scsi_cmnd *))
{
	struct ata_scsi_args args;
	u8 *scsicmd = cmd->cmnd;

	args.id = id;
	args.cmd = cmd;
	args.done = done;

	switch(scsicmd[0]) {
		/* no-op's, complete with success */
		case SYNCHRONIZE_CACHE:
		case REZERO_UNIT:
		case SEEK_6:
		case SEEK_10:
		case TEST_UNIT_READY:
		case FORMAT_UNIT:		/* FIXME: correct? */
		case SEND_DIAGNOSTIC:		/* FIXME: correct? */
			ata_scsi_rbuf_fill(&args, ata_scsiop_noop);
			break;

		case INQUIRY:
			if (scsicmd[1] & 2)	           /* is CmdDt set?  */
				ata_bad_cdb(cmd, done);
			else if ((scsicmd[1] & 1) == 0)    /* is EVPD clear? */
				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_std);
			else if (scsicmd[2] == 0x00)
				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_00);
			else if (scsicmd[2] == 0x80)
				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_80);
			else if (scsicmd[2] == 0x83)
				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_83);
			else
				ata_bad_cdb(cmd, done);
			break;

		case MODE_SENSE:
		case MODE_SENSE_10:
			ata_scsi_rbuf_fill(&args, ata_scsiop_mode_sense);
			break;

		case MODE_SELECT:	/* unconditionally return */
		case MODE_SELECT_10:	/* bad-field-in-cdb */
			ata_bad_cdb(cmd, done);
			break;

		case READ_CAPACITY:
			ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
			break;

		case SERVICE_ACTION_IN:
			if ((scsicmd[1] & 0x1f) == SAI_READ_CAPACITY_16)
				ata_scsi_rbuf_fill(&args, ata_scsiop_read_cap);
			else
				ata_bad_cdb(cmd, done);
			break;

		case REPORT_LUNS:
			ata_scsi_rbuf_fill(&args, ata_scsiop_report_luns);
			break;

		/* mandantory commands we haven't implemented yet */
		case REQUEST_SENSE:

		/* all other commands */
		default:
			ata_bad_scsiop(cmd, done);
			break;
	}
}