xref: /openbsd/sys/scsi/ch.c (revision 07ea8d15)
1 /*	$OpenBSD: ch.c,v 1.6 1996/08/12 10:21:41 deraadt Exp $	*/
2 /*	$NetBSD: ch.c,v 1.21 1996/04/19 00:02:29 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1996 Jason R. Thorpe <thorpej@and.com>
6  * All rights reserved.
7  *
8  * Partially based on an autochanger driver written by Stefan Grefen
9  * and on an autochanger driver written by the Systems Programming Group
10  * at the University of Utah Computer Science Department.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. All advertising materials mentioning features or use of this software
21  *    must display the following acknowledgements:
22  *	This product includes software developed by Jason R. Thorpe
23  *	for And Communications, http://www.and.com/
24  * 4. The name of the author may not be used to endorse or promote products
25  *    derived from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
32  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
33  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
34  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
35  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/errno.h>
43 #include <sys/ioctl.h>
44 #include <sys/buf.h>
45 #include <sys/proc.h>
46 #include <sys/user.h>
47 #include <sys/chio.h>
48 #include <sys/device.h>
49 #include <sys/malloc.h>
50 #include <sys/conf.h>
51 
52 #include <scsi/scsi_all.h>
53 #include <scsi/scsi_changer.h>
54 #include <scsi/scsiconf.h>
55 
56 #define CHRETRIES	2
57 #define CHUNIT(x)	(minor((x)))
58 
59 struct ch_softc {
60 	struct device	sc_dev;		/* generic device info */
61 	struct scsi_link *sc_link;	/* link in the SCSI bus */
62 
63 	int		sc_picker;	/* current picker */
64 
65 	/*
66 	 * The following information is obtained from the
67 	 * element address assignment page.
68 	 */
69 	int		sc_firsts[4];	/* firsts, indexed by CHET_* */
70 	int		sc_counts[4];	/* counts, indexed by CHET_* */
71 
72 	/*
73 	 * The following mask defines the legal combinations
74 	 * of elements for the MOVE MEDIUM command.
75 	 */
76 	u_int8_t	sc_movemask[4];
77 
78 	/*
79 	 * As above, but for EXCHANGE MEDIUM.
80 	 */
81 	u_int8_t	sc_exchangemask[4];
82 
83 	int		flags;		/* misc. info */
84 };
85 
86 /* sc_flags */
87 #define CHF_ROTATE	0x01		/* picker can rotate */
88 
89 /* Autoconfiguration glue */
90 int	chmatch __P((struct device *, void *, void *));
91 void	chattach __P((struct device *, struct device *, void *));
92 
93 struct cfattach ch_ca = {
94 	sizeof(struct ch_softc), chmatch, chattach
95 };
96 
97 struct cfdriver ch_cd = {
98 	NULL, "ch", DV_DULL
99 };
100 
101 struct scsi_inquiry_pattern ch_patterns[] = {
102 	{T_CHANGER, T_REMOV,
103 	 "",		"",		""},
104 };
105 
106 /* SCSI glue */
107 struct scsi_device ch_switch = {
108 	NULL, NULL, NULL, NULL
109 };
110 
111 int	ch_move __P((struct ch_softc *, struct changer_move *));
112 int	ch_exchange __P((struct ch_softc *, struct changer_exchange *));
113 int	ch_position __P((struct ch_softc *, struct changer_position *));
114 int	ch_usergetelemstatus __P((struct ch_softc *, int, u_int8_t *));
115 int	ch_getelemstatus __P((struct ch_softc *, int, int, caddr_t, size_t));
116 int	ch_get_params __P((struct ch_softc *, int));
117 
118 int
119 chmatch(parent, match, aux)
120 	struct device *parent;
121 	void *match, *aux;
122 {
123 	struct scsibus_attach_args *sa = aux;
124 	int priority;
125 
126 	(void)scsi_inqmatch(sa->sa_inqbuf,
127 	    (caddr_t)ch_patterns, sizeof(ch_patterns)/sizeof(ch_patterns[0]),
128 	    sizeof(ch_patterns[0]), &priority);
129 
130 	return (priority);
131 }
132 
133 void
134 chattach(parent, self, aux)
135 	struct device *parent, *self;
136 	void *aux;
137 {
138 	struct ch_softc *sc = (struct ch_softc *)self;
139 	struct scsibus_attach_args *sa = aux;
140 	struct scsi_link *link = sa->sa_sc_link;
141 
142 	/* Glue into the SCSI bus */
143 	sc->sc_link = link;
144 	link->device = &ch_switch;
145 	link->device_softc = sc;
146 	link->openings = 1;
147 
148 	printf("\n");
149 
150 	/*
151 	 * Get information about the device.  Note we can't use
152 	 * interrupts yet.
153 	 */
154 	if (ch_get_params(sc, SCSI_AUTOCONF))
155 		printf("%s: offline\n", sc->sc_dev.dv_xname);
156 	else {
157 		printf("%s: %d slot%s, %d drive%s, %d picker%s",
158 		    sc->sc_dev.dv_xname,
159 		    sc->sc_counts[CHET_ST], (sc->sc_counts[CHET_ST] > 1) ?
160 		    "s" : "",
161 		    sc->sc_counts[CHET_DT], (sc->sc_counts[CHET_DT] > 1) ?
162 		    "s" : "",
163 		    sc->sc_counts[CHET_MT], (sc->sc_counts[CHET_MT] > 1) ?
164 		    "s" : "");
165 		if (sc->sc_counts[CHET_IE])
166 			printf(", %d portal%s", sc->sc_counts[CHET_IE],
167 			    (sc->sc_counts[CHET_IE] > 1) ? "s" : "");
168 		printf("\n");
169 #ifdef CHANGER_DEBUG
170 		printf("%s: move mask: 0x%x 0x%x 0x%x 0x%x\n",
171 		    sc->sc_dev.dv_xname,
172 		    sc->sc_movemask[CHET_MT], sc->sc_movemask[CHET_ST],
173 		    sc->sc_movemask[CHET_IE], sc->sc_movemask[CHET_DT]);
174 		printf("%s: exchange mask: 0x%x 0x%x 0x%x 0x%x\n",
175 		    sc->sc_dev.dv_xname,
176 		    sc->sc_exchangemask[CHET_MT], sc->sc_exchangemask[CHET_ST],
177 		    sc->sc_exchangemask[CHET_IE], sc->sc_exchangemask[CHET_DT]);
178 #endif /* CHANGER_DEBUG */
179 	}
180 
181 	/* Default the current picker. */
182 	sc->sc_picker = sc->sc_firsts[CHET_MT];
183 }
184 
185 int
186 chopen(dev, flags, fmt, p)
187 	dev_t dev;
188 	int flags, fmt;
189 	struct proc *p;
190 {
191 	struct ch_softc *sc;
192 	int unit, error = 0;
193 
194 	unit = CHUNIT(dev);
195 	if ((unit >= ch_cd.cd_ndevs) ||
196 	    ((sc = ch_cd.cd_devs[unit]) == NULL))
197 		return (ENXIO);
198 
199 	/*
200 	 * Only allow one open at a time.
201 	 */
202 	if (sc->sc_link->flags & SDEV_OPEN)
203 		return (EBUSY);
204 
205 	sc->sc_link->flags |= SDEV_OPEN;
206 
207 	/*
208 	 * Absorb any unit attention errors.  Ignore "not ready"
209 	 * since this might occur if e.g. a tape isn't actually
210 	 * loaded in the drive.
211 	 */
212 	error = scsi_test_unit_ready(sc->sc_link,
213 	    SCSI_IGNORE_NOT_READY|SCSI_IGNORE_MEDIA_CHANGE);
214 	if (error)
215 		goto bad;
216 
217 	/*
218 	 * Make sure our parameters are up to date.
219 	 */
220 	if ((error = ch_get_params(sc, 0)) != 0)
221 		goto bad;
222 
223 	return (0);
224 
225  bad:
226 	sc->sc_link->flags &= ~SDEV_OPEN;
227 	return (error);
228 }
229 
230 int
231 chclose(dev, flags, fmt, p)
232 	dev_t dev;
233 	int flags, fmt;
234 	struct proc *p;
235 {
236 	struct ch_softc *sc = ch_cd.cd_devs[CHUNIT(dev)];
237 
238 	sc->sc_link->flags &= ~SDEV_OPEN;
239 	return (0);
240 }
241 
242 int
243 chioctl(dev, cmd, data, flags, p)
244 	dev_t dev;
245 	u_long cmd;
246 	caddr_t data;
247 	int flags;
248 	struct proc *p;
249 {
250 	struct ch_softc *sc = ch_cd.cd_devs[CHUNIT(dev)];
251 	int error = 0;
252 
253 	switch (cmd) {
254 	case CHIOMOVE:
255 		error = ch_move(sc, (struct changer_move *)data);
256 		break;
257 
258 	case CHIOEXCHANGE:
259 		error = ch_exchange(sc, (struct changer_exchange *)data);
260 		break;
261 
262 	case CHIOPOSITION:
263 		error = ch_position(sc, (struct changer_position *)data);
264 		break;
265 
266 	case CHIOGPICKER:
267 		*(int *)data = sc->sc_picker - sc->sc_firsts[CHET_MT];
268 		break;
269 
270 	case CHIOSPICKER:	{
271 		int new_picker = *(int *)data;
272 
273 		if (new_picker > (sc->sc_counts[CHET_MT] - 1))
274 			return (EINVAL);
275 		sc->sc_picker = sc->sc_firsts[CHET_MT] + new_picker;
276 		break;		}
277 
278 	case CHIOGPARAMS:	{
279 		struct changer_params *cp = (struct changer_params *)data;
280 
281 		cp->cp_curpicker = sc->sc_picker - sc->sc_firsts[CHET_MT];
282 		cp->cp_npickers = sc->sc_counts[CHET_MT];
283 		cp->cp_nslots = sc->sc_counts[CHET_ST];
284 		cp->cp_nportals = sc->sc_counts[CHET_IE];
285 		cp->cp_ndrives = sc->sc_counts[CHET_DT];
286 		break;		}
287 
288 	case CHIOGSTATUS:	{
289 		struct changer_element_status *ces =
290 		    (struct changer_element_status *)data;
291 
292 		error = ch_usergetelemstatus(sc, ces->ces_type, ces->ces_data);
293 		break;		}
294 
295 	/* Implement prevent/allow? */
296 
297 	default:
298 		error = scsi_do_safeioctl(sc->sc_link, dev, cmd, data,
299 		    flags, p);
300 		break;
301 	}
302 
303 	return (error);
304 }
305 
306 int
307 ch_move(sc, cm)
308 	struct ch_softc *sc;
309 	struct changer_move *cm;
310 {
311 	struct scsi_move_medium cmd;
312 	u_int16_t fromelem, toelem;
313 
314 	/*
315 	 * Check arguments.
316 	 */
317 	if ((cm->cm_fromtype > CHET_DT) || (cm->cm_totype > CHET_DT))
318 		return (EINVAL);
319 	if ((cm->cm_fromunit > (sc->sc_counts[cm->cm_fromtype] - 1)) ||
320 	    (cm->cm_tounit > (sc->sc_counts[cm->cm_totype] - 1)))
321 		return (ENODEV);
322 
323 	/*
324 	 * Check the request against the changer's capabilities.
325 	 */
326 	if ((sc->sc_movemask[cm->cm_fromtype] & (1 << cm->cm_totype)) == 0)
327 		return (EINVAL);
328 
329 	/*
330 	 * Calculate the source and destination elements.
331 	 */
332 	fromelem = sc->sc_firsts[cm->cm_fromtype] + cm->cm_fromunit;
333 	toelem = sc->sc_firsts[cm->cm_totype] + cm->cm_tounit;
334 
335 	/*
336 	 * Build the SCSI command.
337 	 */
338 	bzero(&cmd, sizeof(cmd));
339 	cmd.opcode = MOVE_MEDIUM;
340 	_lto2b(sc->sc_picker, cmd.tea);
341 	_lto2b(fromelem, cmd.src);
342 	_lto2b(toelem, cmd.dst);
343 	if (cm->cm_flags & CM_INVERT)
344 		cmd.flags |= MOVE_MEDIUM_INVERT;
345 
346 	/*
347 	 * Send command to changer.
348 	 */
349 	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
350 	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
351 }
352 
353 int
354 ch_exchange(sc, ce)
355 	struct ch_softc *sc;
356 	struct changer_exchange *ce;
357 {
358 	struct scsi_exchange_medium cmd;
359 	u_int16_t src, dst1, dst2;
360 
361 	/*
362 	 * Check arguments.
363 	 */
364 	if ((ce->ce_srctype > CHET_DT) || (ce->ce_fdsttype > CHET_DT) ||
365 	    (ce->ce_sdsttype > CHET_DT))
366 		return (EINVAL);
367 	if ((ce->ce_srcunit > (sc->sc_counts[ce->ce_srctype] - 1)) ||
368 	    (ce->ce_fdstunit > (sc->sc_counts[ce->ce_fdsttype] - 1)) ||
369 	    (ce->ce_sdstunit > (sc->sc_counts[ce->ce_sdsttype] - 1)))
370 		return (ENODEV);
371 
372 	/*
373 	 * Check the request against the changer's capabilities.
374 	 */
375 	if (((sc->sc_exchangemask[ce->ce_srctype] &
376 	     (1 << ce->ce_fdsttype)) == 0) ||
377 	    ((sc->sc_exchangemask[ce->ce_fdsttype] &
378 	     (1 << ce->ce_sdsttype)) == 0))
379 		return (EINVAL);
380 
381 	/*
382 	 * Calculate the source and destination elements.
383 	 */
384 	src = sc->sc_firsts[ce->ce_srctype] + ce->ce_srcunit;
385 	dst1 = sc->sc_firsts[ce->ce_fdsttype] + ce->ce_fdstunit;
386 	dst2 = sc->sc_firsts[ce->ce_sdsttype] + ce->ce_sdstunit;
387 
388 	/*
389 	 * Build the SCSI command.
390 	 */
391 	bzero(&cmd, sizeof(cmd));
392 	cmd.opcode = EXCHANGE_MEDIUM;
393 	_lto2b(sc->sc_picker, cmd.tea);
394 	_lto2b(src, cmd.src);
395 	_lto2b(dst1, cmd.fdst);
396 	_lto2b(dst2, cmd.sdst);
397 	if (ce->ce_flags & CE_INVERT1)
398 		cmd.flags |= EXCHANGE_MEDIUM_INV1;
399 	if (ce->ce_flags & CE_INVERT2)
400 		cmd.flags |= EXCHANGE_MEDIUM_INV2;
401 
402 	/*
403 	 * Send command to changer.
404 	 */
405 	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
406 	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
407 }
408 
409 int
410 ch_position(sc, cp)
411 	struct ch_softc *sc;
412 	struct changer_position *cp;
413 {
414 	struct scsi_position_to_element cmd;
415 	u_int16_t dst;
416 
417 	/*
418 	 * Check arguments.
419 	 */
420 	if (cp->cp_type > CHET_DT)
421 		return (EINVAL);
422 	if (cp->cp_unit > (sc->sc_counts[cp->cp_type] - 1))
423 		return (ENODEV);
424 
425 	/*
426 	 * Calculate the destination element.
427 	 */
428 	dst = sc->sc_firsts[cp->cp_type] + cp->cp_unit;
429 
430 	/*
431 	 * Build the SCSI command.
432 	 */
433 	bzero(&cmd, sizeof(cmd));
434 	cmd.opcode = POSITION_TO_ELEMENT;
435 	_lto2b(sc->sc_picker, cmd.tea);
436 	_lto2b(dst, cmd.dst);
437 	if (cp->cp_flags & CP_INVERT)
438 		cmd.flags |= POSITION_TO_ELEMENT_INVERT;
439 
440 	/*
441 	 * Send command to changer.
442 	 */
443 	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
444 	    sizeof(cmd), NULL, 0, CHRETRIES, 100000, NULL, 0));
445 }
446 
447 /*
448  * Perform a READ ELEMENT STATUS on behalf of the user, and return to
449  * the user only the data the user is interested in (i.e. an array of
450  * flags bytes).
451  */
452 int
453 ch_usergetelemstatus(sc, chet, uptr)
454 	struct ch_softc *sc;
455 	int chet;
456 	u_int8_t *uptr;
457 {
458 	struct read_element_status_header *st_hdr;
459 	struct read_element_status_page_header *pg_hdr;
460 	struct read_element_status_descriptor *desc;
461 	caddr_t data = NULL;
462 	size_t size, desclen;
463 	int avail, i, error = 0;
464 	u_int8_t *user_data = NULL;
465 
466 	/*
467 	 * If there are no elements of the requested type in the changer,
468 	 * the request is invalid.
469 	 */
470 	if (sc->sc_counts[chet] == 0)
471 		return (EINVAL);
472 
473 	/*
474 	 * Request one descriptor for the given element type.  This
475 	 * is used to determine the size of the descriptor so that
476 	 * we can allocate enough storage for all of them.  We assume
477 	 * that the first one can fit into 1k.
478 	 */
479 	data = (caddr_t)malloc(1024, M_DEVBUF, M_WAITOK);
480 	error = ch_getelemstatus(sc, sc->sc_firsts[chet], 1, data, 1024);
481 	if (error)
482 		goto done;
483 
484 	st_hdr = (struct read_element_status_header *)data;
485 	pg_hdr = (struct read_element_status_page_header *)((u_long)st_hdr +
486 	    sizeof(struct read_element_status_header));
487 	desclen = _2btol(pg_hdr->edl);
488 
489 	size = sizeof(struct read_element_status_header) +
490 	    sizeof(struct read_element_status_page_header) +
491 	    (desclen * sc->sc_counts[chet]);
492 
493 	/*
494 	 * Reallocate storage for descriptors and get them from the
495 	 * device.
496 	 */
497 	free(data, M_DEVBUF);
498 	data = (caddr_t)malloc(size, M_DEVBUF, M_WAITOK);
499 	error = ch_getelemstatus(sc, sc->sc_firsts[chet],
500 	    sc->sc_counts[chet], data, size);
501 	if (error)
502 		goto done;
503 
504 	/*
505 	 * Fill in the user status array.
506 	 */
507 	st_hdr = (struct read_element_status_header *)data;
508 	avail = _2btol(st_hdr->count);
509 	if (avail != sc->sc_counts[chet])
510 		printf("%s: warning, READ ELEMENT STATUS avail != count\n",
511 		    sc->sc_dev.dv_xname);
512 
513 	user_data = (u_int8_t *)malloc(avail, M_DEVBUF, M_WAITOK);
514 
515 	desc = (struct read_element_status_descriptor *)((u_long)data +
516 	    sizeof(struct read_element_status_header) +
517 	    sizeof(struct read_element_status_page_header));
518 	for (i = 0; i < avail; ++i) {
519 		user_data[i] = desc->flags1;
520 		(u_long)desc += desclen;
521 	}
522 
523 	/* Copy flags array out to userspace. */
524 	error = copyout(user_data, uptr, avail);
525 
526  done:
527 	if (data != NULL)
528 		free(data, M_DEVBUF);
529 	if (user_data != NULL)
530 		free(user_data, M_DEVBUF);
531 	return (error);
532 }
533 
534 int
535 ch_getelemstatus(sc, first, count, data, datalen)
536 	struct ch_softc *sc;
537 	int first, count;
538 	caddr_t data;
539 	size_t datalen;
540 {
541 	struct scsi_read_element_status cmd;
542 
543 	/*
544 	 * Build SCSI command.
545 	 */
546 	bzero(&cmd, sizeof(cmd));
547 	cmd.opcode = READ_ELEMENT_STATUS;
548 	_lto2b(first, cmd.sea);
549 	_lto2b(count, cmd.count);
550 	_lto3b(datalen, cmd.len);
551 
552 	/*
553 	 * Send command to changer.
554 	 */
555 	return (scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
556 	    sizeof(cmd), (u_char *)data, datalen, CHRETRIES, 100000, NULL, 0));
557 }
558 
559 
560 /*
561  * Ask the device about itself and fill in the parameters in our
562  * softc.
563  */
564 int
565 ch_get_params(sc, scsiflags)
566 	struct ch_softc *sc;
567 	int scsiflags;
568 {
569 	struct scsi_mode_sense cmd;
570 	struct scsi_mode_sense_data {
571 		struct scsi_mode_header header;
572 		union {
573 			struct page_element_address_assignment ea;
574 			struct page_transport_geometry_parameters tg;
575 			struct page_device_capabilities cap;
576 		} pages;
577 	} sense_data;
578 	int error, from;
579 	u_int8_t *moves, *exchanges;
580 
581 	/*
582 	 * Grab info from the element address assignment page.
583 	 */
584 	bzero(&cmd, sizeof(cmd));
585 	bzero(&sense_data, sizeof(sense_data));
586 	cmd.opcode = MODE_SENSE;
587 	cmd.byte2 |= 0x08;	/* disable block descriptors */
588 	cmd.page = 0x1d;
589 	cmd.length = (sizeof(sense_data) & 0xff);
590 	error = scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
591 	    sizeof(cmd), (u_char *)&sense_data, sizeof(sense_data), CHRETRIES,
592 	    6000, NULL, scsiflags | SCSI_DATA_IN);
593 	if (error) {
594 		printf("%s: could not sense element address page\n",
595 		    sc->sc_dev.dv_xname);
596 		return (error);
597 	}
598 
599 	sc->sc_firsts[CHET_MT] = _2btol(sense_data.pages.ea.mtea);
600 	sc->sc_counts[CHET_MT] = _2btol(sense_data.pages.ea.nmte);
601 	sc->sc_firsts[CHET_ST] = _2btol(sense_data.pages.ea.fsea);
602 	sc->sc_counts[CHET_ST] = _2btol(sense_data.pages.ea.nse);
603 	sc->sc_firsts[CHET_IE] = _2btol(sense_data.pages.ea.fieea);
604 	sc->sc_counts[CHET_IE] = _2btol(sense_data.pages.ea.niee);
605 	sc->sc_firsts[CHET_DT] = _2btol(sense_data.pages.ea.fdtea);
606 	sc->sc_counts[CHET_DT] = _2btol(sense_data.pages.ea.ndte);
607 
608 	/* XXX ask for page trasport geom */
609 
610 	/*
611 	 * Grab info from the capabilities page.
612 	 */
613 	bzero(&cmd, sizeof(cmd));
614 	bzero(&sense_data, sizeof(sense_data));
615 	cmd.opcode = MODE_SENSE;
616 	cmd.byte2 |= 0x08;	/* disable block descriptors */
617 	cmd.page = 0x1f;
618 	cmd.length = (sizeof(sense_data) & 0xff);
619 	error = scsi_scsi_cmd(sc->sc_link, (struct scsi_generic *)&cmd,
620 	    sizeof(cmd), (u_char *)&sense_data, sizeof(sense_data), CHRETRIES,
621 	    6000, NULL, scsiflags | SCSI_DATA_IN);
622 	if (error) {
623 		printf("%s: could not sense capabilities page\n",
624 		    sc->sc_dev.dv_xname);
625 		return (error);
626 	}
627 
628 	bzero(sc->sc_movemask, sizeof(sc->sc_movemask));
629 	bzero(sc->sc_exchangemask, sizeof(sc->sc_exchangemask));
630 	moves = &sense_data.pages.cap.move_from_mt;
631 	exchanges = &sense_data.pages.cap.exchange_with_mt;
632 	for (from = CHET_MT; from <= CHET_DT; ++from) {
633 		sc->sc_movemask[from] = moves[from];
634 		sc->sc_exchangemask[from] = exchanges[from];
635 	}
636 
637 	sc->sc_link->flags |= SDEV_MEDIA_LOADED;
638 	return (0);
639 }
640