summaryrefslogtreecommitdiff
path: root/sys/scsi/scsi_base.c
blob: 42e47dbcb856619ce2fff5403af768e9e6e731c1 (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
/*	$OpenBSD: scsi_base.c,v 1.11 1997/04/14 04:09:07 downsj Exp $	*/
/*	$NetBSD: scsi_base.c,v 1.43 1997/04/02 02:29:36 mycroft Exp $	*/

/*
 * Copyright (c) 1994, 1995, 1997 Charles M. Hannum.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Charles M. Hannum.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Originally written by Julian Elischer (julian@dialix.oz.au)
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/buf.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/device.h>
#include <sys/proc.h>

#include <scsi/scsi_all.h>
#include <scsi/scsi_disk.h>
#include <scsi/scsiconf.h>

LIST_HEAD(xs_free_list, scsi_xfer) xs_free_list;

static __inline struct scsi_xfer *scsi_make_xs __P((struct scsi_link *,
						    struct scsi_generic *,
						    int cmdlen,
						    u_char *data_addr,
						    int datalen,
						    int retries,
						    int timeout,
						    struct buf *,
						    int flags));

int sc_err1 __P((struct scsi_xfer *, int));
int scsi_interpret_sense __P((struct scsi_xfer *));

/*
 * Get a scsi transfer structure for the caller. Charge the structure
 * to the device that is referenced by the sc_link structure. If the 
 * sc_link structure has no 'credits' then the device already has the
 * maximum number or outstanding operations under way. In this stage,
 * wait on the structure so that when one is freed, we are awoken again
 * If the SCSI_NOSLEEP flag is set, then do not wait, but rather, return
 * a NULL pointer, signifying that no slots were available
 * Note in the link structure, that we are waiting on it.
 */

struct scsi_xfer *
scsi_get_xs(sc_link, flags)
	struct scsi_link *sc_link;	/* who to charge the xs to */
	int flags;			/* if this call can sleep */
{
	struct scsi_xfer *xs;
	int s;

	SC_DEBUG(sc_link, SDEV_DB3, ("scsi_get_xs\n"));
	s = splbio();
	while (sc_link->openings <= 0) {
		SC_DEBUG(sc_link, SDEV_DB3, ("sleeping\n"));
		if ((flags & SCSI_NOSLEEP) != 0) {
			splx(s);
			return 0;
		}
		sc_link->flags |= SDEV_WAITING;
		(void) tsleep(sc_link, PRIBIO, "getxs", 0);
	}
	sc_link->openings--;
	if ((xs = xs_free_list.lh_first) != NULL) {
		LIST_REMOVE(xs, free_list);
		splx(s);
	} else {
		splx(s);
		SC_DEBUG(sc_link, SDEV_DB3, ("making\n"));
		xs = malloc(sizeof(*xs), M_DEVBUF,
		    ((flags & SCSI_NOSLEEP) != 0 ? M_NOWAIT : M_WAITOK));
		if (!xs) {
			sc_print_addr(sc_link);
			printf("cannot allocate scsi xs\n");
			return 0;
		}
	}

	SC_DEBUG(sc_link, SDEV_DB3, ("returning\n"));
	xs->flags = INUSE | flags;
	return xs;
}

/*
 * Given a scsi_xfer struct, and a device (referenced through sc_link)
 * return the struct to the free pool and credit the device with it
 * If another process is waiting for an xs, do a wakeup, let it proceed
 */
void 
scsi_free_xs(xs, flags)
	struct scsi_xfer *xs;
	int flags;
{
	struct scsi_link *sc_link = xs->sc_link;

	xs->flags &= ~INUSE;
	LIST_INSERT_HEAD(&xs_free_list, xs, free_list);

	SC_DEBUG(sc_link, SDEV_DB3, ("scsi_free_xs\n"));
	/* if was 0 and someone waits, wake them up */
	sc_link->openings++;
	if ((sc_link->flags & SDEV_WAITING) != 0) {
		sc_link->flags &= ~SDEV_WAITING;
		wakeup(sc_link);
	} else {
		if (sc_link->device->start) {
			SC_DEBUG(sc_link, SDEV_DB2, ("calling private start()\n"));
			(*(sc_link->device->start)) (sc_link->device_softc);
		}
	}
}

/*
 * Make a scsi_xfer, and return a pointer to it.
 */
static __inline struct scsi_xfer *
scsi_make_xs(sc_link, scsi_cmd, cmdlen, data_addr, datalen,
	     retries, timeout, bp, flags)
	struct scsi_link *sc_link;
	struct scsi_generic *scsi_cmd;
	int cmdlen;
	u_char *data_addr;
	int datalen;
	int retries;
	int timeout;
	struct buf *bp;
	int flags;
{
	struct scsi_xfer *xs;

	if ((xs = scsi_get_xs(sc_link, flags)) == NULL)
		return NULL;

	/*
	 * Fill out the scsi_xfer structure.  We don't know whose context
	 * the cmd is in, so copy it.
	 */
	xs->sc_link = sc_link;
	bcopy(scsi_cmd, &xs->cmdstore, cmdlen);
	xs->cmd = &xs->cmdstore;
	xs->cmdlen = cmdlen;
	xs->data = data_addr;
	xs->datalen = datalen;
	xs->retries = retries;
	xs->timeout = timeout;
	xs->bp = bp;

	/*
	 * Set the LUN in the CDB if we have an older device.  We also
	 * set it for more modern SCSI-II devices "just in case".
	 */
	if ((sc_link->scsi_version & SID_ANSII) <= 2)
		xs->cmd->bytes[0] |=
		    ((sc_link->lun << SCSI_CMD_LUN_SHIFT) & SCSI_CMD_LUN_MASK);

	return xs;
}

/*
 * Find out from the device what its capacity is.
 */
u_long
scsi_size(sc_link, flags)
	struct scsi_link *sc_link;
	int flags;
{
	struct scsi_read_cap_data rdcap;
	struct scsi_read_capacity scsi_cmd;

	/*
	 * make up a scsi command and ask the scsi driver to do
	 * it for you.
	 */
	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = READ_CAPACITY;

	/*
	 * If the command works, interpret the result as a 4 byte
	 * number of blocks
	 */
	if (scsi_scsi_cmd(sc_link, (struct scsi_generic *)&scsi_cmd,
			  sizeof(scsi_cmd), (u_char *)&rdcap, sizeof(rdcap),
			  2, 20000, NULL, flags | SCSI_DATA_IN) != 0) {
		sc_print_addr(sc_link);
		printf("could not get size\n");
		return 0;
	}

	return _4btol(rdcap.addr) + 1;
}

/*
 * Get scsi driver to send a "are you ready?" command
 */
int 
scsi_test_unit_ready(sc_link, flags)
	struct scsi_link *sc_link;
	int flags;
{
	struct scsi_test_unit_ready scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = TEST_UNIT_READY;

	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
			     sizeof(scsi_cmd), 0, 0, 2, 10000, NULL, flags);
}

/*
 * Do a scsi operation, asking a device to run as SCSI-II if it can.
 */
int 
scsi_change_def(sc_link, flags)
	struct scsi_link *sc_link;
	int flags;
{
	struct scsi_changedef scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = CHANGE_DEFINITION;
	scsi_cmd.how = SC_SCSI_2;

	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
			     sizeof(scsi_cmd), 0, 0, 2, 100000, NULL, flags);
}

/*
 * Do a scsi operation asking a device what it is
 * Use the scsi_cmd routine in the switch table.
 */
int 
scsi_inquire(sc_link, inqbuf, flags)
	struct scsi_link *sc_link;
	struct scsi_inquiry_data *inqbuf;
	int flags;
{
	struct scsi_inquiry scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = INQUIRY;
	scsi_cmd.length = sizeof(struct scsi_inquiry_data);

	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
			     sizeof(scsi_cmd), (u_char *) inqbuf,
			     sizeof(struct scsi_inquiry_data), 2, 10000, NULL,
			     SCSI_DATA_IN | flags);
}

/*
 * Prevent or allow the user to remove the media
 */
int 
scsi_prevent(sc_link, type, flags)
	struct scsi_link *sc_link;
	int type, flags;
{
	struct scsi_prevent scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = PREVENT_ALLOW;
	scsi_cmd.how = type;
	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
			     sizeof(scsi_cmd), 0, 0, 2, 5000, NULL, flags);
}

/*
 * Get scsi driver to send a "start up" command
 */
int 
scsi_start(sc_link, type, flags)
	struct scsi_link *sc_link;
	int type, flags;
{
	struct scsi_start_stop scsi_cmd;

	bzero(&scsi_cmd, sizeof(scsi_cmd));
	scsi_cmd.opcode = START_STOP;
	scsi_cmd.byte2 = 0x00;
	scsi_cmd.how = type;
	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &scsi_cmd,
			     sizeof(scsi_cmd), 0, 0, 2,
			     type == SSS_START ? 30000 : 10000, NULL, flags);
}

/*
 * This routine is called by the scsi interrupt when the transfer is complete.
 */
void 
scsi_done(xs)
	struct scsi_xfer *xs;
{
	struct scsi_link *sc_link = xs->sc_link;
	struct buf *bp;
	int error;

	SC_DEBUG(sc_link, SDEV_DB2, ("scsi_done\n"));
#ifdef	SCSIDEBUG
	if ((sc_link->flags & SDEV_DB1) != 0)
		show_scsi_cmd(xs);
#endif /* SCSIDEBUG */

	/*
 	 * If it's a user level request, bypass all usual completion processing,
 	 * let the user work it out.. We take reponsibility for freeing the
 	 * xs when the user returns. (and restarting the device's queue).
 	 */
	if ((xs->flags & SCSI_USER) != 0) {
		SC_DEBUG(sc_link, SDEV_DB3, ("calling user done()\n"));
		scsi_user_done(xs); /* to take a copy of the sense etc. */
		SC_DEBUG(sc_link, SDEV_DB3, ("returned from user done()\n "));

		scsi_free_xs(xs, SCSI_NOSLEEP); /* restarts queue too */
		SC_DEBUG(sc_link, SDEV_DB3, ("returning to adapter\n"));
		return;
	}

	if (!((xs->flags & (SCSI_NOSLEEP | SCSI_POLL)) == SCSI_NOSLEEP)) {
		/*
		 * if it's a normal upper level request, then ask
		 * the upper level code to handle error checking
		 * rather than doing it here at interrupt time
		 */
		wakeup(xs);
		return;
	}

	/*
	 * Go and handle errors now.
	 * If it returns ERESTART then we should RETRY
	 */
retry:
	error = sc_err1(xs, 1);
	if (error == ERESTART) {
		switch ((*(sc_link->adapter->scsi_cmd)) (xs)) {
		case SUCCESSFULLY_QUEUED:
			return;

		case TRY_AGAIN_LATER:
			xs->error = XS_BUSY;
		case COMPLETE:
			goto retry;
		}
	}

	bp = xs->bp;
	if (bp) {
		if (error) {
			bp->b_error = error;
			bp->b_flags |= B_ERROR;
			bp->b_resid = bp->b_bcount;
		} else {
			bp->b_error = 0;
			bp->b_resid = xs->resid;
		}
	}
	if (sc_link->device->done) {
		/*
		 * Tell the device the operation is actually complete.
		 * No more will happen with this xfer.  This for
		 * notification of the upper-level driver only; they
		 * won't be returning any meaningful information to us.
		 */
		(*sc_link->device->done)(xs);
	}
	scsi_free_xs(xs, SCSI_NOSLEEP);
	if (bp)
		biodone(bp);
}

int
scsi_execute_xs(xs)
	struct scsi_xfer *xs;
{
	int error;
	int s;

	xs->flags &= ~ITSDONE;
	xs->error = XS_NOERROR;
	xs->resid = xs->datalen;

retry:
	/*
	 * Do the transfer. If we are polling we will return:
	 * COMPLETE,  Was poll, and scsi_done has been called
	 * TRY_AGAIN_LATER, Adapter short resources, try again
	 * 
	 * if under full steam (interrupts) it will return:
	 * SUCCESSFULLY_QUEUED, will do a wakeup when complete
	 * TRY_AGAIN_LATER, (as for polling)
	 * After the wakeup, we must still check if it succeeded
	 * 
	 * If we have a SCSI_NOSLEEP (typically because we have a buf)
	 * we just return.  All the error proccessing and the buffer
	 * code both expect us to return straight to them, so as soon
	 * as the command is queued, return.
	 */
	switch ((*(xs->sc_link->adapter->scsi_cmd)) (xs)) {
	case SUCCESSFULLY_QUEUED:
		if ((xs->flags & (SCSI_NOSLEEP | SCSI_POLL)) == SCSI_NOSLEEP)
			return EJUSTRETURN;
#ifdef DIAGNOSTIC
		if (xs->flags & SCSI_NOSLEEP)
			panic("scsi_execute_xs: NOSLEEP and POLL");
#endif
		s = splbio();
		while ((xs->flags & ITSDONE) == 0)
			tsleep(xs, PRIBIO + 1, "scsi_scsi_cmd", 0);
		splx(s);
	case COMPLETE:		/* Polling command completed ok */
		if (xs->bp)
			return EJUSTRETURN;
	doit:
		SC_DEBUG(xs->sc_link, SDEV_DB3, ("back in cmd()\n"));
		if ((error = sc_err1(xs, 0)) != ERESTART)
			return error;
		goto retry;

	case TRY_AGAIN_LATER:	/* adapter resource shortage */
		xs->error = XS_BUSY;
		goto doit;

	default:
		panic("scsi_execute_xs: invalid return code");
	}

#ifdef DIAGNOSTIC
	panic("scsi_execute_xs: impossible");
#endif
	return EINVAL;
}

/*
 * ask the scsi driver to perform a command for us.
 * tell it where to read/write the data, and how
 * long the data is supposed to be. If we have  a buf
 * to associate with the transfer, we need that too.
 */
int 
scsi_scsi_cmd(sc_link, scsi_cmd, cmdlen, data_addr, datalen,
    retries, timeout, bp, flags)
	struct scsi_link *sc_link;
	struct scsi_generic *scsi_cmd;
	int cmdlen;
	u_char *data_addr;
	int datalen;
	int retries;
	int timeout;
	struct buf *bp;
	int flags;
{
	struct scsi_xfer *xs;
	int error;

	SC_DEBUG(sc_link, SDEV_DB2, ("scsi_cmd\n"));

#ifdef DIAGNOSTIC
	if (bp != 0 && (flags & SCSI_NOSLEEP) == 0)
		panic("scsi_scsi_cmd: buffer without nosleep");
#endif

	if ((xs = scsi_make_xs(sc_link, scsi_cmd, cmdlen, data_addr, datalen,
	    retries, timeout, bp, flags)) == NULL)
		return ENOMEM;

	if ((error = scsi_execute_xs(xs)) == EJUSTRETURN)
		return 0;

	/*
	 * we have finished with the xfer stuct, free it and
	 * check if anyone else needs to be started up.
	 */
	scsi_free_xs(xs, flags);
	return error;
}

int 
sc_err1(xs, async)
	struct scsi_xfer *xs;
	int async;
{
	int error;

	SC_DEBUG(xs->sc_link, SDEV_DB3, ("sc_err1,err = 0x%x \n", xs->error));

	/*
	 * If it has a buf, we might be working with
	 * a request from the buffer cache or some other
	 * piece of code that requires us to process
	 * errors at inetrrupt time. We have probably
	 * been called by scsi_done()
	 */
	switch (xs->error) {
	case XS_NOERROR:	/* nearly always hit this one */
		error = 0;
		break;

	case XS_SENSE:
		if ((error = scsi_interpret_sense(xs)) == ERESTART)
			goto retry;
		SC_DEBUG(xs->sc_link, SDEV_DB3,
		    ("scsi_interpret_sense returned %d\n", error));
		break;

	case XS_BUSY:
		if (xs->retries) {
			if ((xs->flags & SCSI_POLL) != 0)
				delay(1000000);
			else if ((xs->flags & SCSI_NOSLEEP) == 0)
				tsleep(&lbolt, PRIBIO, "scbusy", 0);
			else
#if 0
				timeout(scsi_requeue, xs, hz);
#else
				goto lose;
#endif
		}
	case XS_TIMEOUT:
	retry:
		if (xs->retries--) {
			xs->error = XS_NOERROR;
			xs->flags &= ~ITSDONE;
			return ERESTART;
		}
	case XS_DRIVER_STUFFUP:
	lose:
		error = EIO;
		break;

	case XS_SELTIMEOUT:
		/* XXX Disable device? */
		error = EIO;
		break;

	default:
		sc_print_addr(xs->sc_link);
		printf("unknown error category from scsi driver\n");
		error = EIO;
		break;
	}

	return error;
}

/*
 * Look at the returned sense and act on the error, determining
 * the unix error number to pass back.  (0 = report no error)
 *
 * THIS IS THE DEFAULT ERROR HANDLER
 */
int 
scsi_interpret_sense(xs)
	struct scsi_xfer *xs;
{
	struct scsi_sense_data *sense;
	struct scsi_link *sc_link = xs->sc_link;
	u_int8_t key;
	u_int32_t info;
	int error;

	static char *error_mes[] = {
		"soft error (corrected)",
		"not ready", "medium error",
		"non-media hardware failure", "illegal request",
		"unit attention", "readonly device",
		"no data found", "vendor unique",
		"copy aborted", "command aborted",
		"search returned equal", "volume overflow",
		"verify miscompare", "unknown error key"
	};

	sense = &xs->sense;
#ifdef	SCSIDEBUG
	if ((sc_link->flags & SDEV_DB1) != 0) {
		int count;
		printf("code%x valid%x ",
		    sense->error_code & SSD_ERRCODE,
		    sense->error_code & SSD_ERRCODE_VALID ? 1 : 0);
		printf("seg%x key%x ili%x eom%x fmark%x\n",
		    sense->segment,
		    sense->flags & SSD_KEY,
		    sense->flags & SSD_ILI ? 1 : 0,
		    sense->flags & SSD_EOM ? 1 : 0,
		    sense->flags & SSD_FILEMARK ? 1 : 0);
		printf("info: %x %x %x %x followed by %d extra bytes\n",
		    sense->info[0],
		    sense->info[1],
		    sense->info[2],
		    sense->info[3],
		    sense->extra_len);
		printf("extra: ");
		for (count = 0; count < sense->extra_len; count++)
			printf("%x ", sense->extra_bytes[count]);
		printf("\n");
	}
#endif	/*SCSIDEBUG */
	/*
	 * If the device has it's own error handler, call it first.
	 * If it returns a legit error value, return that, otherwise
	 * it wants us to continue with normal error processing.
	 */
	if (sc_link->device->err_handler) {
		SC_DEBUG(sc_link, SDEV_DB2, ("calling private err_handler()\n"));
		error = (*sc_link->device->err_handler) (xs);
		if (error != -1)
			return error;		/* error >= 0  better ? */
	}
	/* otherwise use the default */
	switch (sense->error_code & SSD_ERRCODE) {
		/*
		 * If it's code 70, use the extended stuff and interpret the key
		 */
	case 0x71:		/* delayed error */
		sc_print_addr(sc_link);
		key = sense->flags & SSD_KEY;
		printf(" DELAYED ERROR, key = 0x%x\n", key);
	case 0x70:
		if ((sense->error_code & SSD_ERRCODE_VALID) != 0)
			info = _4btol(sense->info);
		else
			info = 0;
		key = sense->flags & SSD_KEY;

		switch (key) {
		case 0x0:	/* NO SENSE */
		case 0x1:	/* RECOVERED ERROR */
			if (xs->resid == xs->datalen)
				xs->resid = 0;	/* not short read */
		case 0xc:	/* EQUAL */
			error = 0;
			break;
		case 0x2:	/* NOT READY */
			if ((sc_link->flags & SDEV_REMOVABLE) != 0)
				sc_link->flags &= ~SDEV_MEDIA_LOADED;
			if ((xs->flags & SCSI_IGNORE_NOT_READY) != 0)
				return 0;
			if (xs->retries && !(sc_link->flags & SDEV_REMOVABLE)) {
				delay(1000000);
				return ERESTART;
			}
			if ((xs->flags & SCSI_SILENT) != 0)
				return EIO;
			error = EIO;
			break;
		case 0x5:	/* ILLEGAL REQUEST */
			if ((xs->flags & SCSI_IGNORE_ILLEGAL_REQUEST) != 0)
				return 0;
			if ((xs->flags & SCSI_SILENT) != 0)
				return EIO;
			error = EINVAL;
			break;
		case 0x6:	/* UNIT ATTENTION */
			if ((sc_link->flags & SDEV_REMOVABLE) != 0)
				sc_link->flags &= ~SDEV_MEDIA_LOADED;
			if ((xs->flags & SCSI_IGNORE_MEDIA_CHANGE) != 0 ||
			    /* XXX Should reupload any transient state. */
			    (sc_link->flags & SDEV_REMOVABLE) == 0)
				return ERESTART;
			if ((xs->flags & SCSI_SILENT) != 0)
				return EIO;
			error = EIO;
			break;
		case 0x7:	/* DATA PROTECT */
			error = EACCES;
			break;
		case 0x8:	/* BLANK CHECK */
			error = 0;
			break;
		case 0xb:	/* COMMAND ABORTED */
			error = ERESTART;
			break;
		case 0xd:	/* VOLUME OVERFLOW */
			error = ENOSPC;
			break;
		default:
			error = EIO;
			break;
		}

		if (key) {
			sc_print_addr(sc_link);
			printf("%s", error_mes[key - 1]);
			if ((sense->error_code & SSD_ERRCODE_VALID) != 0) {
				switch (key) {
				case 0x2:	/* NOT READY */
				case 0x5:	/* ILLEGAL REQUEST */
				case 0x6:	/* UNIT ATTENTION */
				case 0x7:	/* DATA PROTECT */
					break;
				case 0x8:	/* BLANK CHECK */
					printf(", requested size: %d (decimal)",
					    info);
					break;
				case 0xb:	/* COMMAND ABORTED */
					if (xs->retries)
						printf(", retrying");
					printf(", cmd 0x%x, info 0x%x",
						xs->cmd->opcode, info);
					break;
				default:
					printf(", info = %d (decimal)", info);
				}
			}
			if (sense->extra_len != 0) {
				int n;
				printf(", data =");
				for (n = 0; n < sense->extra_len; n++)
					printf(" %02x", sense->extra_bytes[n]);
			}
			printf("\n");
		}
		return error;

	/*
	 * Not code 70, just report it
	 */
	default:
		sc_print_addr(sc_link);
		printf("error code %d",
		    sense->error_code & SSD_ERRCODE);
		if ((sense->error_code & SSD_ERRCODE_VALID) != 0) {
			struct scsi_sense_data_unextended *usense =
			    (struct scsi_sense_data_unextended *)sense;
			printf(" at block no. %d (decimal)",
			    _3btol(usense->block));
		}
		printf("\n");
		return EIO;
	}
}

/*
 * Utility routines often used in SCSI stuff
 */


/*
 * Print out the scsi_link structure's address info.
 */
void
sc_print_addr(sc_link)
	struct scsi_link *sc_link;
{

	printf("%s(%s:%d:%d): ",
	    sc_link->device_softc ?
	    ((struct device *)sc_link->device_softc)->dv_xname : "probe",
	    ((struct device *)sc_link->adapter_softc)->dv_xname,
	    sc_link->target, sc_link->lun);		
}

#ifdef	SCSIDEBUG
/*
 * Given a scsi_xfer, dump the request, in all it's glory
 */
void
show_scsi_xs(xs)
	struct scsi_xfer *xs;
{
	printf("xs(%p): ", xs);
	printf("flg(0x%x)", xs->flags);
	printf("sc_link(%p)", xs->sc_link);
	printf("retr(0x%x)", xs->retries);
	printf("timo(0x%x)", xs->timeout);
	printf("cmd(%p)", xs->cmd);
	printf("len(0x%x)", xs->cmdlen);
	printf("data(%p)", xs->data);
	printf("len(0x%x)", xs->datalen);
	printf("res(0x%x)", xs->resid);
	printf("err(0x%x)", xs->error);
	printf("bp(%p)", xs->bp);
	show_scsi_cmd(xs);
}

void
show_scsi_cmd(xs)
	struct scsi_xfer *xs;
{
	u_char *b = (u_char *) xs->cmd;
	int     i = 0;

	sc_print_addr(xs->sc_link);
	printf("command: ");

	if ((xs->flags & SCSI_RESET) == 0) {
		while (i < xs->cmdlen) {
			if (i)
				printf(",");
			printf("%x", b[i++]);
		}
		printf("-[%d bytes]\n", xs->datalen);
		if (xs->datalen)
			show_mem(xs->data, min(64, xs->datalen));
	} else
		printf("-RESET-\n");
}

void
show_mem(address, num)
	u_char *address;
	int num;
{
	int x;

	printf("------------------------------");
	for (x = 0; x < num; x++) {
		if ((x % 16) == 0)
			printf("\n%03d: ", x);
		printf("%02x ", *address++);
	}
	printf("\n------------------------------\n");
}
#endif /*SCSIDEBUG */