xref: /netbsd-src/sys/dev/scsipi/st.c (revision 1f2744e6e4915c9da2a3f980279398c4cf7d5e6d)
1 /*	$NetBSD: st.c,v 1.47 1995/03/25 18:41:42 mycroft Exp $	*/
2 
3 /*
4  * Copyright (c) 1994 Charles Hannum.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by Charles Hannum.
17  * 4. The name of the author may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Originally written by Julian Elischer (julian@tfs.com)
34  * for TRW Financial Systems for use under the MACH(2.5) operating system.
35  *
36  * TRW Financial Systems, in accordance with their agreement with Carnegie
37  * Mellon University, makes this software available to CMU to distribute
38  * or use in any manner that they see fit as long as this message is kept with
39  * the software. For this reason TFS also grants any other persons or
40  * organisations permission to use or modify this software.
41  *
42  * TFS supplies this software to be publicly redistributed
43  * on the understanding that TFS is not responsible for the correct
44  * functioning of this software in any circumstances.
45  *
46  * Ported to run under 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
47  * major changes by Julian Elischer (julian@jules.dialix.oz.au) May 1993
48  */
49 
50 /*
51  * To do:
52  * work out some better way of guessing what a good timeout is going
53  * to be depending on whether we expect to retension or not.
54  */
55 
56 #include <sys/types.h>
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/fcntl.h>
60 #include <sys/errno.h>
61 #include <sys/ioctl.h>
62 #include <sys/malloc.h>
63 #include <sys/buf.h>
64 #include <sys/proc.h>
65 #include <sys/user.h>
66 #include <sys/mtio.h>
67 #include <sys/device.h>
68 
69 #include <scsi/scsi_all.h>
70 #include <scsi/scsi_tape.h>
71 #include <scsi/scsiconf.h>
72 
73 /* Defines for device specific stuff */
74 #define DEF_FIXED_BSIZE  512
75 #define	ST_RETRIES	4	/* only on non IO commands */
76 
77 #define STMODE(z)	( minor(z)       & 0x03)
78 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
79 #define STUNIT(z)	((minor(z) >> 4)       )
80 #define CTLMODE	3
81 
82 #define SCSI_2_MAX_DENSITY_CODE	0x17	/* maximum density code specified
83 					 * in SCSI II spec. */
84 /*
85  * Define various devices that we know mis-behave in some way,
86  * and note how they are bad, so we can correct for them
87  */
88 struct modes {
89 	u_int quirks;			/* same definitions as in quirkdata */
90 	int blksize;
91 	u_int8_t density;
92 };
93 
94 struct quirkdata {
95 	u_int quirks;
96 #define	ST_Q_FORCE_BLKSIZE	0x0001
97 #define	ST_Q_SENSE_HELP		0x0002	/* must do READ for good MODE SENSE */
98 #define	ST_Q_IGNORE_LOADS	0x0004
99 #define	ST_Q_BLKSIZE		0x0008	/* variable-block media_blksize > 0 */
100 	u_int page_0_size;
101 #define	MAX_PAGE_0_SIZE	64
102 	struct modes modes[4];
103 };
104 
105 struct st_quirk_inquiry_pattern {
106 	struct scsi_inquiry_pattern pattern;
107 	struct quirkdata quirkdata;
108 };
109 
110 struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
111 	{T_SEQUENTIAL, T_REMOV,
112 	 "        ", "                ", "    ", 0, 0, {
113 		ST_Q_FORCE_BLKSIZE, 512, 0,		/* minor 0-3 */
114 		ST_Q_FORCE_BLKSIZE, 512, QIC_24,	/* minor 4-7 */
115 		ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600,	/* minor 8-11 */
116 		ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250	/* minor 12-15 */
117 	}},
118 	{T_SEQUENTIAL, T_REMOV,
119 	 "TANDBERG", " TDC 3600       ", "",     0, 12, {
120 		0, 0, 0,				/* minor 0-3 */
121 		ST_Q_FORCE_BLKSIZE, 0, QIC_525,		/* minor 4-7 */
122 		0, 0, QIC_150,				/* minor 8-11 */
123 		0, 0, QIC_120				/* minor 12-15 */
124 	}},
125 	/*
126 	 * At least -005 and -007 need this.  I'll assume they all do unless I
127 	 * hear otherwise.  - mycroft, 31MAR1994
128 	 */
129 	{T_SEQUENTIAL, T_REMOV,
130 	 "ARCHIVE ", "VIPER 2525 25462", "",     0, 0, {
131 		ST_Q_SENSE_HELP, 0, 0,			/* minor 0-3 */
132 		ST_Q_SENSE_HELP, 0, QIC_525,		/* minor 4-7 */
133 		0, 0, QIC_150,				/* minor 8-11 */
134 		0, 0, QIC_120				/* minor 12-15 */
135 	}},
136 	/*
137 	 * One user reports that this works for his tape drive.  It probably
138 	 * needs more work.  - mycroft, 09APR1994
139 	 */
140 	{T_SEQUENTIAL, T_REMOV,
141 	 "SANKYO  ", "CP525           ", "",     0, 0, {
142 		ST_Q_FORCE_BLKSIZE, 512, 0,		/* minor 0-3 */
143 		ST_Q_FORCE_BLKSIZE, 512, QIC_525,	/* minor 4-7 */
144 		0, 0, QIC_150,				/* minor 8-11 */
145 		0, 0, QIC_120				/* minor 12-15 */
146 	}},
147 	{T_SEQUENTIAL, T_REMOV,
148 	 "ANRITSU ", "DMT780          ", "",     0, 0, {
149 		ST_Q_FORCE_BLKSIZE, 512, 0,		/* minor 0-3 */
150 		ST_Q_FORCE_BLKSIZE, 512, QIC_525,	/* minor 4-7 */
151 		0, 0, QIC_150,				/* minor 8-11 */
152 		0, 0, QIC_120				/* minor 12-15 */
153 	}},
154 	{T_SEQUENTIAL, T_REMOV,
155 	 "ARCHIVE ", "VIPER 150  21247", "",     0, 12, {
156 		0, 0, 0,				/* minor 0-3 */
157 		0, 0, QIC_150,				/* minor 4-7 */
158 		0, 0, QIC_120,				/* minor 8-11 */
159 		0, 0, QIC_24				/* minor 12-15 */
160 	}},
161 	{T_SEQUENTIAL, T_REMOV,
162 	 "WANGTEK ", "5525ES SCSI REV7", "",     0, 0, {
163 		0, 0, 0,				/* minor 0-3 */
164 		ST_Q_BLKSIZE, 0, QIC_525,		/* minor 4-7 */
165 		0, 0, QIC_150,				/* minor 8-11 */
166 		0, 0, QIC_120				/* minor 12-15 */
167 	}},
168 	{T_SEQUENTIAL, T_REMOV,
169 	 "WangDAT ", "Model 1300      ", "",     0, 0, {
170 		0, 0, 0,				/* minor 0-3 */
171 		ST_Q_FORCE_BLKSIZE, 512, DDS,		/* minor 4-7 */
172 		ST_Q_FORCE_BLKSIZE, 1024, DDS,		/* minor 8-11 */
173 		ST_Q_FORCE_BLKSIZE, 0, DDS		/* minor 12-15 */
174 	}},
175 #if 0
176 	{T_SEQUENTIAL, T_REMOV,
177 	 "EXABYTE ", "EXB-8200        ", "",     0, 12, {
178 		0, 0, 0,				/* minor 0-3 */
179 		0, 0, 0,				/* minor 4-7 */
180 		0, 0, 0,				/* minor 8-11 */
181 		0, 0, 0					/* minor 12-15 */
182 	}},
183 #endif
184 };
185 
186 #define NOEJECT 0
187 #define EJECT 1
188 
189 struct st_softc {
190 	struct device sc_dev;
191 /*--------------------present operating parameters, flags etc.----------------*/
192 	int flags;		/* see below                          */
193 	u_int quirks;		/* quirks for the open mode           */
194 	int blksize;		/* blksize we are using                */
195 	u_int8_t density;	/* present density                    */
196 	u_int page_0_size;	/* size of page 0 data		      */
197 	u_int last_dsty;	/* last density opened               */
198 /*--------------------device/scsi parameters----------------------------------*/
199 	struct scsi_link *sc_link;	/* our link to the adpter etc.        */
200 /*--------------------parameters reported by the device ----------------------*/
201 	int blkmin;		/* min blk size                       */
202 	int blkmax;		/* max blk size                       */
203 	struct quirkdata *quirkdata;	/* if we have a rogue entry           */
204 /*--------------------parameters reported by the device for this media--------*/
205 	u_long numblks;		/* nominal blocks capacity            */
206 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
207 	u_int8_t media_density;	/* this is what it said when asked    */
208 /*--------------------quirks for the whole drive------------------------------*/
209 	u_int drive_quirks;	/* quirks of this drive               */
210 /*--------------------How we should set up when opening each minor device----*/
211 	struct modes modes[4];	/* plus more for each mode            */
212 	u_int8_t  modeflags[4];	/* flags for the modes                */
213 #define DENSITY_SET_BY_USER	0x01
214 #define DENSITY_SET_BY_QUIRK	0x02
215 #define BLKSIZE_SET_BY_USER	0x04
216 #define BLKSIZE_SET_BY_QUIRK	0x08
217 /*--------------------storage for sense data returned by the drive------------*/
218 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
219 						 * additional sense data needed
220 						 * for mode sense/select.
221 						 */
222 	struct buf buf_queue;		/* the queue of pending IO operations */
223 };
224 
225 int stmatch __P((struct device *, void *, void *));
226 void stattach __P((struct device *, struct device *, void *));
227 
228 struct cfdriver stcd = {
229 	NULL, "st", stmatch, stattach, DV_TAPE, sizeof(struct st_softc)
230 };
231 
232 int	st_space __P((struct st_softc *, int number, u_int what, int flags));
233 int	st_rewind __P((struct st_softc *, u_int immediate, int flags));
234 int	st_mode_sense __P((struct st_softc *, int flags));
235 int	st_decide_mode __P((struct st_softc *, boolean first_read));
236 int	st_read_block_limits __P((struct st_softc *, int flags));
237 int	st_touch_tape __P((struct st_softc *));
238 int	st_write_filemarks __P((struct st_softc *, int number, int flags));
239 int	st_load __P((struct st_softc *, u_int type, int flags));
240 int	st_mode_select __P((struct st_softc *, int flags));
241 void    ststrategy();
242 void    stminphys();
243 int	st_check_eod();
244 void    ststart();
245 void	st_unmount();
246 int	st_mount_tape();
247 void	st_loadquirks();
248 void	st_identify_drive();
249 int	st_interpret_sense();
250 
251 struct scsi_device st_switch = {
252 	st_interpret_sense,
253 	ststart,
254 	NULL,
255 	NULL,
256 };
257 
258 #define	ST_INFO_VALID	0x0001
259 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
260 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
261 #define	ST_FIXEDBLOCKS	0x0008
262 #define	ST_AT_FILEMARK	0x0010
263 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
264 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode              */
265 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
266 #define	ST_FM_WRITTEN	0x0100	/*
267 				 * EOF file mark written  -- used with
268 				 * ~ST_WRITTEN to indicate that multiple file
269 				 * marks have been written
270 				 */
271 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
272 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
273 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
274 
275 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
276 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN | \
277 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN | \
278 			 ST_2FM_AT_EOD | ST_PER_ACTION)
279 
280 struct scsi_inquiry_pattern st_patterns[] = {
281 	{T_SEQUENTIAL, T_REMOV,
282 	 "",         "",                 ""},
283 };
284 
285 int
286 stmatch(parent, match, aux)
287 	struct device *parent;
288 	void *match, *aux;
289 {
290 	struct cfdata *cf = match;
291 	struct scsibus_attach_args *sa = aux;
292 	int priority;
293 
294 	(void)scsi_inqmatch(sa->sa_inqbuf,
295 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
296 	    sizeof(st_patterns[0]), &priority);
297 	return (priority);
298 }
299 
300 /*
301  * The routine called by the low level scsi routine when it discovers
302  * A device suitable for this driver
303  */
304 void
305 stattach(parent, self, aux)
306 	struct device *parent, *self;
307 	void *aux;
308 {
309 	struct st_softc *st = (void *)self;
310 	struct scsibus_attach_args *sa = aux;
311 	struct scsi_link *sc_link = sa->sa_sc_link;
312 
313 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
314 
315 	/*
316 	 * Store information needed to contact our base driver
317 	 */
318 	st->sc_link = sc_link;
319 	sc_link->device = &st_switch;
320 	sc_link->device_softc = st;
321 	sc_link->openings = 1;
322 
323 	/*
324 	 * Check if the drive is a known criminal and take
325 	 * Any steps needed to bring it into line
326 	 */
327 	st_identify_drive(st, sa->sa_inqbuf);
328 
329 	/*
330 	 * Use the subdriver to request information regarding
331 	 * the drive. We cannot use interrupts yet, so the
332 	 * request must specify this.
333 	 */
334 	printf(": %s", st->quirkdata ? "rogue, " : "");
335 	if (scsi_test_unit_ready(sc_link,
336 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
337 	    st_mode_sense(st,
338 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
339 		printf("drive empty\n");
340 	else {
341 		printf("density code 0x%x, ", st->media_density);
342 		if (st->media_blksize > 0)
343 			printf("%d-byte", st->media_blksize);
344 		else
345 			printf("variable");
346 		printf(" blocks, write-%s\n",
347 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
348 	}
349 
350 	/*
351 	 * Set up the buf queue for this device
352 	 */
353 	st->buf_queue.b_active = 0;
354 	st->buf_queue.b_actf = 0;
355 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
356 }
357 
358 /*
359  * Use the inquiry routine in 'scsi_base' to get drive info so we can
360  * Further tailor our behaviour.
361  */
362 void
363 st_identify_drive(st, inqbuf)
364 	struct st_softc *st;
365 	struct scsi_inquiry_data *inqbuf;
366 {
367 	struct st_quirk_inquiry_pattern *finger;
368 	int priority;
369 
370 	finger = (struct st_quirk_inquiry_pattern *)scsi_inqmatch(inqbuf,
371 	    (caddr_t)st_quirk_patterns,
372 	    sizeof(st_quirk_patterns)/sizeof(st_quirk_patterns[0]),
373 	    sizeof(st_quirk_patterns[0]), &priority);
374 	if (priority != 0) {
375 		st->quirkdata = &finger->quirkdata;
376 		st->drive_quirks = finger->quirkdata.quirks;
377 		st->quirks = finger->quirkdata.quirks;	/* start value */
378 		st->page_0_size = finger->quirkdata.page_0_size;
379 		st_loadquirks(st);
380 	}
381 }
382 
383 /*
384  * initialise the subdevices to the default (QUIRK) state.
385  * this will remove any setting made by the system operator or previous
386  * operations.
387  */
388 void
389 st_loadquirks(st)
390 	struct st_softc *st;
391 {
392 	int i;
393 	struct	modes *mode;
394 	struct	modes *mode2;
395 
396 	mode = st->quirkdata->modes;
397 	mode2 = st->modes;
398 	for (i = 0; i < 4; i++) {
399 		bzero(mode2, sizeof(struct modes));
400 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
401 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
402 		    DENSITY_SET_BY_USER);
403 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
404 			mode2->blksize = mode->blksize;
405 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
406 		}
407 		if (mode->density) {
408 			mode2->density = mode->density;
409 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
410 		}
411 		mode++;
412 		mode2++;
413 	}
414 }
415 
416 /*
417  * open the device.
418  */
419 int
420 stopen(dev, flags)
421 	dev_t dev;
422 	int flags;
423 {
424 	int unit;
425 	u_int mode, dsty;
426 	int error = 0;
427 	struct st_softc *st;
428 	struct scsi_link *sc_link;
429 
430 	unit = STUNIT(dev);
431 	if (unit >= stcd.cd_ndevs)
432 		return ENXIO;
433 	st = stcd.cd_devs[unit];
434 	if (!st)
435 		return ENXIO;
436 
437 	mode = STMODE(dev);
438 	dsty = STDSTY(dev);
439 	sc_link = st->sc_link;
440 
441 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
442 	    unit, stcd.cd_ndevs));
443 
444 	/*
445 	 * Only allow one at a time
446 	 */
447 	if (sc_link->flags & SDEV_OPEN) {
448 		printf("%s: already open\n", st->sc_dev.dv_xname);
449 		return EBUSY;
450 	}
451 
452 	/*
453 	 * Catch any unit attention errors.
454 	 */
455 	if (error = scsi_test_unit_ready(sc_link,
456 	    SCSI_IGNORE_MEDIA_CHANGE | (mode == CTLMODE ? SCSI_IGNORE_NOT_READY : 0)))
457 		goto bad;
458 
459 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
460 
461 	/*
462 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
463 	 * then the device has been opened to set defaults
464 	 * This mode does NOT ALLOW I/O, only ioctls
465 	 */
466 	if (mode == CTLMODE)
467 		return 0;
468 
469 	/*
470 	 * if it's a different mode, or if the media has been
471 	 * invalidated, unmount the tape from the previous
472 	 * session but continue with open processing
473 	 */
474 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
475 		st_unmount(st, NOEJECT);
476 
477 	/*
478 	 * If we are not mounted, then we should start a new
479 	 * mount session.
480 	 */
481 	if (!(st->flags & ST_MOUNTED)) {
482 		st_mount_tape(dev, flags);
483 		st->last_dsty = dsty;
484 	}
485 
486 	/*
487 	 * Make sure that a tape opened in write-only mode will have
488 	 * file marks written on it when closed, even if not written to.
489 	 * This is for SUN compatibility
490 	 */
491 	if ((flags & O_ACCMODE) == FWRITE)
492 		st->flags |= ST_WRITTEN;
493 
494 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
495 	return 0;
496 
497 bad:
498 	st_unmount(st, NOEJECT);
499 	sc_link->flags &= ~SDEV_OPEN;
500 	return error;
501 }
502 
503 /*
504  * close the device.. only called if we are the LAST
505  * occurence of an open device
506  */
507 int
508 stclose(dev)
509 	dev_t dev;
510 {
511 	struct st_softc *st = stcd.cd_devs[STUNIT(dev)];
512 
513 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
514 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
515 		st_write_filemarks(st, 1, 0);
516 	switch (STMODE(dev)) {
517 	case 0:
518 	case 3:		/* for now */
519 		st_unmount(st, NOEJECT);
520 		break;
521 	case 1:
522 		/* leave mounted unless media seems to have been removed */
523 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
524 			st_unmount(st, NOEJECT);
525 		break;
526 	case 2:
527 		st_unmount(st, EJECT);
528 		break;
529 	}
530 	st->sc_link->flags &= ~SDEV_OPEN;
531 
532 	return 0;
533 }
534 
535 /*
536  * Start a new mount session.
537  * Copy in all the default parameters from the selected device mode.
538  * and try guess any that seem to be defaulted.
539  */
540 int
541 st_mount_tape(dev, flags)
542 	dev_t dev;
543 	int flags;
544 {
545 	int unit;
546 	u_int mode, dsty;
547 	struct st_softc *st;
548 	struct scsi_link *sc_link;
549 	int error = 0;
550 
551 	unit = STUNIT(dev);
552 	mode = STMODE(dev);
553 	dsty = STDSTY(dev);
554 	st = stcd.cd_devs[unit];
555 	sc_link = st->sc_link;
556 
557 	if (st->flags & ST_MOUNTED)
558 		return 0;
559 
560 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
561 	st->flags |= ST_NEW_MOUNT;
562 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
563 	/*
564 	 * If the media is new, then make sure we give it a chance to
565 	 * to do a 'load' instruction.  (We assume it is new.)
566 	 */
567 	if (error = st_load(st, LD_LOAD, 0))
568 		return error;
569 	/*
570 	 * Throw another dummy instruction to catch
571 	 * 'Unit attention' errors. Some drives appear to give
572 	 * these after doing a Load instruction.
573 	 * (noteably some DAT drives)
574 	 */
575 	scsi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
576 
577 	/*
578 	 * Some devices can't tell you much until they have been
579 	 * asked to look at the media. This quirk does this.
580 	 */
581 	if (st->quirks & ST_Q_SENSE_HELP)
582 		if (error = st_touch_tape(st))
583 			return error;
584 	/*
585 	 * Load the physical device parameters
586 	 * loads: blkmin, blkmax
587 	 */
588 	if (error = st_read_block_limits(st, 0))
589 		return error;
590 	/*
591 	 * Load the media dependent parameters
592 	 * includes: media_blksize,media_density,numblks
593 	 * As we have a tape in, it should be reflected here.
594 	 * If not you may need the "quirk" above.
595 	 */
596 	if (error = st_mode_sense(st, 0))
597 		return error;
598 	/*
599 	 * If we have gained a permanent density from somewhere,
600 	 * then use it in preference to the one supplied by
601 	 * default by the driver.
602 	 */
603 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
604 		st->density = st->modes[dsty].density;
605 	else
606 		st->density = st->media_density;
607 	/*
608 	 * If we have gained a permanent blocksize
609 	 * then use it in preference to the one supplied by
610 	 * default by the driver.
611 	 */
612 	st->flags &= ~ST_FIXEDBLOCKS;
613 	if (st->modeflags[dsty] & (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
614 		st->blksize = st->modes[dsty].blksize;
615 		if (st->blksize)
616 			st->flags |= ST_FIXEDBLOCKS;
617 	} else {
618 		if (error = st_decide_mode(st, FALSE))
619 			return error;
620 	}
621 	if (error = st_mode_select(st, 0)) {
622 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
623 		return error;
624 	}
625 	scsi_prevent(sc_link, PR_PREVENT,
626 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
627 	st->flags &= ~ST_NEW_MOUNT;
628 	st->flags |= ST_MOUNTED;
629 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
630 
631 	return 0;
632 }
633 
634 /*
635  * End the present mount session.
636  * Rewind, and optionally eject the tape.
637  * Reset various flags to indicate that all new
638  * operations require another mount operation
639  */
640 void
641 st_unmount(st, eject)
642 	struct st_softc *st;
643 	boolean eject;
644 {
645 	struct scsi_link *sc_link = st->sc_link;
646 	int nmarks;
647 
648 	if (!(st->flags & ST_MOUNTED))
649 		return;
650 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
651 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
652 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
653 	scsi_prevent(sc_link, PR_ALLOW,
654 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
655 	if (eject)
656 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
657 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
658 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
659 }
660 
661 /*
662  * Given all we know about the device, media, mode, 'quirks' and
663  * initial operation, make a decision as to how we should be set
664  * to run (regarding blocking and EOD marks)
665  */
666 int
667 st_decide_mode(st, first_read)
668 	struct st_softc *st;
669 	boolean	first_read;
670 {
671 #ifdef SCSIDEBUG
672 	struct scsi_link *sc_link = st->sc_link;
673 #endif
674 
675 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
676 
677 	/*
678 	 * If the drive can only handle fixed-length blocks and only at
679 	 * one size, perhaps we should just do that.
680 	 */
681 	if (st->blkmin && (st->blkmin == st->blkmax)) {
682 		st->flags |= ST_FIXEDBLOCKS;
683 		st->blksize = st->blkmin;
684 		SC_DEBUG(sc_link, SDEV_DB3,
685 		    ("blkmin == blkmax of %d\n", st->blkmin));
686 		goto done;
687 	}
688 	/*
689 	 * If the tape density mandates (or even suggests) use of fixed
690 	 * or variable-length blocks, comply.
691 	 */
692 	switch (st->density) {
693 	case HALFINCH_800:
694 	case HALFINCH_1600:
695 	case HALFINCH_6250:
696 	case DDS:
697 		st->flags &= ~ST_FIXEDBLOCKS;
698 		st->blksize = 0;
699 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
700 		goto done;
701 	case QIC_11:
702 	case QIC_24:
703 	case QIC_120:
704 	case QIC_150:
705 	case QIC_525:
706 	case QIC_1320:
707 		st->flags |= ST_FIXEDBLOCKS;
708 		if (st->media_blksize > 0)
709 			st->blksize = st->media_blksize;
710 		else
711 			st->blksize = DEF_FIXED_BSIZE;
712 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
713 		goto done;
714 	}
715 	/*
716 	 * If we're about to read the tape, perhaps we should choose
717 	 * fixed or variable-length blocks and block size according to
718 	 * what the drive found on the tape.
719 	 */
720 	if (first_read &&
721 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
722 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
723 	    (st->media_blksize == 1024))) {
724 		if (st->media_blksize > 0)
725 			st->flags |= ST_FIXEDBLOCKS;
726 		else
727 			st->flags &= ~ST_FIXEDBLOCKS;
728 		st->blksize = st->media_blksize;
729 		SC_DEBUG(sc_link, SDEV_DB3,
730 		    ("Used media_blksize of %d\n", st->media_blksize));
731 		goto done;
732 	}
733 	/*
734 	 * We're getting no hints from any direction.  Choose variable-
735 	 * length blocks arbitrarily.
736 	 */
737 	st->flags &= ~ST_FIXEDBLOCKS;
738 	st->blksize = 0;
739 	SC_DEBUG(sc_link, SDEV_DB3,
740 	    ("Give up and default to variable mode\n"));
741 
742 done:
743 	/*
744 	 * Decide whether or not to write two file marks to signify end-
745 	 * of-data.  Make the decision as a function of density.  If
746 	 * the decision is not to use a second file mark, the SCSI BLANK
747 	 * CHECK condition code will be recognized as end-of-data when
748 	 * first read.
749 	 * (I think this should be a by-product of fixed/variable..julian)
750 	 */
751 	switch (st->density) {
752 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
753 	case QIC_11:
754 	case QIC_24:
755 	case QIC_120:
756 	case QIC_150:
757 	case QIC_525:
758 	case QIC_1320:
759 		st->flags &= ~ST_2FM_AT_EOD;
760 		break;
761 	default:
762 		st->flags |= ST_2FM_AT_EOD;
763 	}
764 	return 0;
765 }
766 
767 /*
768  * trim the size of the transfer if needed,
769  * called by physio
770  * basically the smaller of our min and the scsi driver's
771  * minphys
772  */
773 void
774 stminphys(bp)
775 	struct buf *bp;
776 {
777 	register struct st_softc *st = stcd.cd_devs[STUNIT(bp->b_dev)];
778 
779 	(st->sc_link->adapter->scsi_minphys) (bp);
780 }
781 
782 /*
783  * Actually translate the requested transfer into
784  * one the physical driver can understand
785  * The transfer is described by a buf and will include
786  * only one physical transfer.
787  */
788 void
789 ststrategy(bp)
790 	struct buf *bp;
791 {
792 	struct st_softc *st = stcd.cd_devs[STUNIT(bp->b_dev)];
793 	struct buf *dp;
794 	int opri;
795 
796 	SC_DEBUG(st->sc_link, SDEV_DB1,
797 	    ("ststrategy %d bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
798 	/*
799 	 * If it's a null transfer, return immediatly
800 	 */
801 	if (bp->b_bcount == 0)
802 		goto done;
803 	/*
804 	 * Odd sized request on fixed drives are verboten
805 	 */
806 	if (st->flags & ST_FIXEDBLOCKS) {
807 		if (bp->b_bcount % st->blksize) {
808 			printf("%s: bad request, must be multiple of %d\n",
809 			    st->sc_dev.dv_xname, st->blksize);
810 			bp->b_error = EIO;
811 			goto bad;
812 		}
813 	}
814 	/*
815 	 * as are out-of-range requests on variable drives.
816 	 */
817 	else if (bp->b_bcount < st->blkmin ||
818 		 (st->blkmax && bp->b_bcount > st->blkmax)) {
819 		printf("%s: bad request, must be between %d and %d\n",
820 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
821 		bp->b_error = EIO;
822 		goto bad;
823 	}
824 	stminphys(bp);
825 	opri = splbio();
826 
827 	/*
828 	 * Place it in the queue of activities for this tape
829 	 * at the end (a bit silly because we only have on user..
830 	 * (but it could fork()))
831 	 */
832 	dp = &st->buf_queue;
833 	bp->b_actf = NULL;
834 	bp->b_actb = dp->b_actb;
835 	*dp->b_actb = bp;
836 	dp->b_actb = &bp->b_actf;
837 
838 	/*
839 	 * Tell the device to get going on the transfer if it's
840 	 * not doing anything, otherwise just wait for completion
841 	 * (All a bit silly if we're only allowing 1 open but..)
842 	 */
843 	ststart(st);
844 
845 	splx(opri);
846 	return;
847 bad:
848 	bp->b_flags |= B_ERROR;
849 done:
850 	/*
851 	 * Correctly set the buf to indicate a completed xfer
852 	 */
853 	iodone(bp);
854 	return;
855 }
856 
857 /*
858  * ststart looks to see if there is a buf waiting for the device
859  * and that the device is not already busy. If both are true,
860  * It dequeues the buf and creates a scsi command to perform the
861  * transfer required. The transfer request will call scsi_done
862  * on completion, which will in turn call this routine again
863  * so that the next queued transfer is performed.
864  * The bufs are queued by the strategy routine (ststrategy)
865  *
866  * This routine is also called after other non-queued requests
867  * have been made of the scsi driver, to ensure that the queue
868  * continues to be drained.
869  * ststart() is called at splbio
870  */
871 void
872 ststart(st)
873 	struct st_softc *st;
874 {
875 	struct scsi_link *sc_link = st->sc_link;
876 	register struct buf *bp, *dp;
877 	struct scsi_rw_tape cmd;
878 	int flags;
879 
880 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
881 	/*
882 	 * See if there is a buf to do and we are not already
883 	 * doing one
884 	 */
885 	while (sc_link->openings > 0) {
886 		/* if a special awaits, let it proceed first */
887 		if (sc_link->flags & SDEV_WAITING) {
888 			sc_link->flags &= ~SDEV_WAITING;
889 			wakeup((caddr_t)sc_link);
890 			return;
891 		}
892 
893 		bp = st->buf_queue.b_actf;
894 		if (!bp)
895 			return;	/* no work to bother with */
896 		if (dp = bp->b_actf)
897 			dp->b_actb = bp->b_actb;
898 		else
899 			st->buf_queue.b_actb = bp->b_actb;
900 		*bp->b_actb = dp;
901 
902 		/*
903 		 * if the device has been unmounted byt the user
904 		 * then throw away all requests until done
905 		 */
906 		if (!(st->flags & ST_MOUNTED) ||
907 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
908 			/* make sure that one implies the other.. */
909 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
910 			bp->b_flags |= B_ERROR;
911 			bp->b_error = EIO;
912 			biodone(bp);
913 			continue;
914 		}
915 		/*
916 		 * only FIXEDBLOCK devices have pending operations
917 		 */
918 		if (st->flags & ST_FIXEDBLOCKS) {
919 			/*
920 			 * If we are at a filemark but have not reported it yet
921 			 * then we should report it now
922 			 */
923 			if (st->flags & ST_AT_FILEMARK) {
924 				if ((bp->b_flags & B_READ) == B_WRITE) {
925 					/*
926 					 * Handling of ST_AT_FILEMARK in
927 					 * st_space will fill in the right file
928 					 * mark count.
929 					 * Back up over filemark
930 					 */
931 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
932 						bp->b_flags |= B_ERROR;
933 						bp->b_error = EIO;
934 						biodone(bp);
935 						continue;
936 					}
937 				} else {
938 					bp->b_resid = bp->b_bcount;
939 					bp->b_error = 0;
940 					bp->b_flags &= ~B_ERROR;
941 					st->flags &= ~ST_AT_FILEMARK;
942 					biodone(bp);
943 					continue;	/* seek more work */
944 				}
945 			}
946 			/*
947 			 * If we are at EIO (e.g. EOM) but have not reported it
948 			 * yet then we should report it now
949 			 */
950 			if (st->flags & ST_EIO_PENDING) {
951 				bp->b_resid = bp->b_bcount;
952 				bp->b_error = EIO;
953 				bp->b_flags |= B_ERROR;
954 				st->flags &= ~ST_EIO_PENDING;
955 				biodone(bp);
956 				continue;	/* seek more work */
957 			}
958 		}
959 
960 		/*
961 		 *  Fill out the scsi command
962 		 */
963 		bzero(&cmd, sizeof(cmd));
964 		if ((bp->b_flags & B_READ) == B_WRITE) {
965 			cmd.opcode = WRITE;
966 			st->flags &= ~ST_FM_WRITTEN;
967 			st->flags |= ST_WRITTEN;
968 			flags = SCSI_DATA_OUT;
969 		} else {
970 			cmd.opcode = READ;
971 			flags = SCSI_DATA_IN;
972 		}
973 
974 		/*
975 		 * Handle "fixed-block-mode" tape drives by using the
976 		 * block count instead of the length.
977 		 */
978 		if (st->flags & ST_FIXEDBLOCKS) {
979 			cmd.byte2 |= SRW_FIXED;
980 			lto3b(bp->b_bcount / st->blksize, cmd.len);
981 		} else
982 			lto3b(bp->b_bcount, cmd.len);
983 
984 		/*
985 		 * go ask the adapter to do all this for us
986 		 */
987 		if (scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
988 		    sizeof(cmd), (u_char *) bp->b_data, bp->b_bcount, 0,
989 		    100000, bp, flags | SCSI_NOSLEEP))
990 			printf("%s: not queued\n", st->sc_dev.dv_xname);
991 	} /* go back and see if we can cram more work in.. */
992 }
993 
994 /*
995  * Perform special action on behalf of the user;
996  * knows about the internals of this device
997  */
998 int
999 stioctl(dev, cmd, arg, flag, p)
1000 	dev_t dev;
1001 	u_long cmd;
1002 	caddr_t arg;
1003 	int flag;
1004 	struct proc *p;
1005 {
1006 	int error = 0;
1007 	int unit;
1008 	int number, nmarks, dsty;
1009 	int flags;
1010 	struct st_softc *st;
1011 	int hold_blksize;
1012 	u_int8_t hold_density;
1013 	struct mtop *mt = (struct mtop *) arg;
1014 
1015 	/*
1016 	 * Find the device that the user is talking about
1017 	 */
1018 	flags = 0;		/* give error messages, act on errors etc. */
1019 	unit = STUNIT(dev);
1020 	dsty = STDSTY(dev);
1021 	st = stcd.cd_devs[unit];
1022 	hold_blksize = st->blksize;
1023 	hold_density = st->density;
1024 
1025 	switch (cmd) {
1026 
1027 	case MTIOCGET: {
1028 		struct mtget *g = (struct mtget *) arg;
1029 
1030 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1031 		bzero(g, sizeof(struct mtget));
1032 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1033 		g->mt_blksiz = st->blksize;
1034 		g->mt_density = st->density;
1035 		g->mt_mblksiz[0] = st->modes[0].blksize;
1036 		g->mt_mblksiz[1] = st->modes[1].blksize;
1037 		g->mt_mblksiz[2] = st->modes[2].blksize;
1038 		g->mt_mblksiz[3] = st->modes[3].blksize;
1039 		g->mt_mdensity[0] = st->modes[0].density;
1040 		g->mt_mdensity[1] = st->modes[1].density;
1041 		g->mt_mdensity[2] = st->modes[2].density;
1042 		g->mt_mdensity[3] = st->modes[3].density;
1043 		break;
1044 	}
1045 	case MTIOCTOP: {
1046 
1047 		SC_DEBUG(st->sc_link, SDEV_DB1,
1048 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op, mt->mt_count));
1049 
1050 		/* compat: in U*x it is a short */
1051 		number = mt->mt_count;
1052 		switch ((short) (mt->mt_op)) {
1053 		case MTWEOF:	/* write an end-of-file record */
1054 			error = st_write_filemarks(st, number, flags);
1055 			break;
1056 		case MTBSF:	/* backward space file */
1057 			number = -number;
1058 		case MTFSF:	/* forward space file */
1059 			error = st_check_eod(st, FALSE, &nmarks, flags);
1060 			if (!error)
1061 				error = st_space(st, number - nmarks,
1062 				    SP_FILEMARKS, flags);
1063 			break;
1064 		case MTBSR:	/* backward space record */
1065 			number = -number;
1066 		case MTFSR:	/* forward space record */
1067 			error = st_check_eod(st, TRUE, &nmarks, flags);
1068 			if (!error)
1069 				error = st_space(st, number, SP_BLKS, flags);
1070 			break;
1071 		case MTREW:	/* rewind */
1072 			error = st_rewind(st, 0, flags);
1073 			break;
1074 		case MTOFFL:	/* rewind and put the drive offline */
1075 			st_unmount(st, EJECT);
1076 			break;
1077 		case MTNOP:	/* no operation, sets status only */
1078 			break;
1079 		case MTRETEN:	/* retension the tape */
1080 			error = st_load(st, LD_RETENSION, flags);
1081 			if (!error)
1082 				error = st_load(st, LD_LOAD, flags);
1083 			break;
1084 		case MTEOM:	/* forward space to end of media */
1085 			error = st_check_eod(st, FALSE, &nmarks, flags);
1086 			if (!error)
1087 				error = st_space(st, 1, SP_EOM, flags);
1088 			break;
1089 		case MTCACHE:	/* enable controller cache */
1090 		case MTNOCACHE:	/* disable controller cache */
1091 			break;
1092 		case MTSETBSIZ:	/* Set block size for device */
1093 #ifdef	NOTYET
1094 			if (!(st->flags & ST_NEW_MOUNT)) {
1095 				uprintf("re-mount tape before changing blocksize");
1096 				error = EINVAL;
1097 				break;
1098 			}
1099 #endif
1100 			if (number == 0) {
1101 				st->flags &= ~ST_FIXEDBLOCKS;
1102 			} else {
1103 				if ((st->blkmin || st->blkmax) &&
1104 				    (number < st->blkmin ||
1105 				    number > st->blkmax)) {
1106 					error = EINVAL;
1107 					break;
1108 				}
1109 				st->flags |= ST_FIXEDBLOCKS;
1110 			}
1111 			st->blksize = number;
1112 			st->flags |= ST_BLOCK_SET;	/*XXX */
1113 			goto try_new_value;
1114 
1115 		case MTSETDNSTY:	/* Set density for device and mode */
1116 			if (number > SCSI_2_MAX_DENSITY_CODE)
1117 				error = EINVAL;
1118 			else
1119 				st->density = number;
1120 			goto try_new_value;
1121 
1122 		default:
1123 			error = EINVAL;
1124 		}
1125 		break;
1126 	}
1127 	case MTIOCIEOT:
1128 	case MTIOCEEOT:
1129 		break;
1130 	default:
1131 		if (STMODE(dev) == CTLMODE)
1132 			error = scsi_do_ioctl(st->sc_link, dev, cmd, arg, flag, p);
1133 		else
1134 			error = ENOTTY;
1135 		break;
1136 	}
1137 	return error;
1138 /*-----------------------------*/
1139 try_new_value:
1140 	/*
1141 	 * Check that the mode being asked for is aggreeable to the
1142 	 * drive. If not, put it back the way it was.
1143 	 */
1144 	if (error = st_mode_select(st, 0)) {	/* put it back as it was */
1145 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1146 		st->density = hold_density;
1147 		st->blksize = hold_blksize;
1148 		if (st->blksize)
1149 			st->flags |= ST_FIXEDBLOCKS;
1150 		else
1151 			st->flags &= ~ST_FIXEDBLOCKS;
1152 		return error;
1153 	}
1154 	/*
1155 	 * As the drive liked it, if we are setting a new default,
1156 	 * set it into the structures as such.
1157 	 *
1158 	 * The means for deciding this are not finalised yet
1159 	 */
1160 	if (STMODE(dev) == 0x03) {
1161 		/* special mode */
1162 		/* XXX */
1163 		switch ((short) (mt->mt_op)) {
1164 		case MTSETBSIZ:
1165 			st->modes[dsty].blksize = st->blksize;
1166 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1167 			break;
1168 		case MTSETDNSTY:
1169 			st->modes[dsty].density = st->density;
1170 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1171 			break;
1172 		}
1173 	}
1174 	return 0;
1175 }
1176 
1177 /*
1178  * Do a synchronous read.
1179  */
1180 int
1181 st_read(st, buf, size, flags)
1182 	struct st_softc *st;
1183 	int size;
1184 	int flags;
1185 	char *buf;
1186 {
1187 	struct scsi_rw_tape cmd;
1188 
1189 	/*
1190 	 * If it's a null transfer, return immediatly
1191 	 */
1192 	if (size == 0)
1193 		return 0;
1194 	bzero(&cmd, sizeof(cmd));
1195 	cmd.opcode = READ;
1196 	if (st->flags & ST_FIXEDBLOCKS) {
1197 		cmd.byte2 |= SRW_FIXED;
1198 		lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1199 		    cmd.len);
1200 	} else
1201 		lto3b(size, cmd.len);
1202 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1203 	    sizeof(cmd), (u_char *) buf, size, 0, 100000, NULL,
1204 	    flags | SCSI_DATA_IN);
1205 }
1206 
1207 #ifdef	__STDC__
1208 #define b2tol(a)	(((unsigned)(a##_1) << 8) + (unsigned)a##_0)
1209 #else
1210 #define b2tol(a)	(((unsigned)(a/**/_1) << 8) + (unsigned)a/**/_0)
1211 #endif
1212 
1213 /*
1214  * Ask the drive what it's min and max blk sizes are.
1215  */
1216 int
1217 st_read_block_limits(st, flags)
1218 	struct st_softc *st;
1219 	int flags;
1220 {
1221 	struct scsi_block_limits cmd;
1222 	struct scsi_block_limits_data block_limits;
1223 	struct scsi_link *sc_link = st->sc_link;
1224 	int error;
1225 
1226 	/*
1227 	 * First check if we have it all loaded
1228 	 */
1229 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1230 		return 0;
1231 
1232 	/*
1233 	 * do a 'Read Block Limits'
1234 	 */
1235 	bzero(&cmd, sizeof(cmd));
1236 	cmd.opcode = READ_BLOCK_LIMITS;
1237 
1238 	/*
1239 	 * do the command, update the global values
1240 	 */
1241 	if (error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1242 	    sizeof(cmd), (u_char *) &block_limits, sizeof(block_limits),
1243 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN))
1244 		return error;
1245 
1246 	st->blkmin = b2tol(block_limits.min_length);
1247 	st->blkmax = _3btol(&block_limits.max_length_2);
1248 
1249 	SC_DEBUG(sc_link, SDEV_DB3,
1250 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1251 	return 0;
1252 }
1253 
1254 /*
1255  * Get the scsi driver to send a full inquiry to the
1256  * device and use the results to fill out the global
1257  * parameter structure.
1258  *
1259  * called from:
1260  * attach
1261  * open
1262  * ioctl (to reset original blksize)
1263  */
1264 int
1265 st_mode_sense(st, flags)
1266 	struct st_softc *st;
1267 	int flags;
1268 {
1269 	u_int scsi_sense_len;
1270 	int error;
1271 	struct scsi_mode_sense cmd;
1272 	struct scsi_sense {
1273 		struct scsi_mode_header header;
1274 		struct scsi_blk_desc blk_desc;
1275 		u_char sense_data[MAX_PAGE_0_SIZE];
1276 	} scsi_sense;
1277 	struct scsi_link *sc_link = st->sc_link;
1278 
1279 	scsi_sense_len = 12 + st->page_0_size;
1280 
1281 	/*
1282 	 * Set up a mode sense
1283 	 */
1284 	bzero(&cmd, sizeof(cmd));
1285 	cmd.opcode = MODE_SENSE;
1286 	cmd.length = scsi_sense_len;
1287 
1288 	/*
1289 	 * do the command, but we don't need the results
1290 	 * just print them for our interest's sake, if asked,
1291 	 * or if we need it as a template for the mode select
1292 	 * store it away.
1293 	 */
1294 	if (error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1295 	    sizeof(cmd), (u_char *) &scsi_sense, scsi_sense_len,
1296 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN))
1297 		return error;
1298 
1299 	st->numblks = _3btol(scsi_sense.blk_desc.nblocks);
1300 	st->media_blksize = _3btol(scsi_sense.blk_desc.blklen);
1301 	st->media_density = scsi_sense.blk_desc.density;
1302 	if (scsi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1303 		st->flags |= ST_READONLY;
1304 	SC_DEBUG(sc_link, SDEV_DB3,
1305 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1306 	    st->media_density, st->media_blksize,
1307 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1308 	SC_DEBUG(sc_link, SDEV_DB3,
1309 	    ("%sbuffered\n",
1310 	    scsi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1311 	if (st->page_0_size)
1312 		bcopy(scsi_sense.sense_data, st->sense_data, st->page_0_size);
1313 	sc_link->flags |= SDEV_MEDIA_LOADED;
1314 	return 0;
1315 }
1316 
1317 /*
1318  * Send a filled out parameter structure to the drive to
1319  * set it into the desire modes etc.
1320  */
1321 int
1322 st_mode_select(st, flags)
1323 	struct st_softc *st;
1324 	int flags;
1325 {
1326 	u_int scsi_select_len;
1327 	int error;
1328 	struct scsi_mode_select cmd;
1329 	struct scsi_select {
1330 		struct scsi_mode_header header;
1331 		struct scsi_blk_desc blk_desc;
1332 		u_char sense_data[MAX_PAGE_0_SIZE];
1333 	} scsi_select;
1334 	struct scsi_link *sc_link = st->sc_link;
1335 
1336 	scsi_select_len = 12 + st->page_0_size;
1337 
1338 	/*
1339 	 * Set up for a mode select
1340 	 */
1341 	bzero(&cmd, sizeof(cmd));
1342 	cmd.opcode = MODE_SELECT;
1343 	cmd.length = scsi_select_len;
1344 
1345 	bzero(&scsi_select, scsi_select_len);
1346 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1347 	scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1348 	scsi_select.blk_desc.density = st->density;
1349 	if (st->flags & ST_FIXEDBLOCKS)
1350 		lto3b(st->blksize, scsi_select.blk_desc.blklen);
1351 	if (st->page_0_size)
1352 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1353 
1354 	/*
1355 	 * do the command
1356 	 */
1357 	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1358 	    sizeof(cmd), (u_char *) &scsi_select, scsi_select_len,
1359 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1360 }
1361 
1362 /*
1363  * skip N blocks/filemarks/seq filemarks/eom
1364  */
1365 int
1366 st_space(st, number, what, flags)
1367 	struct st_softc *st;
1368 	u_int what;
1369 	int flags;
1370 	int number;
1371 {
1372 	struct scsi_space cmd;
1373 	int error;
1374 
1375 	switch (what) {
1376 	case SP_BLKS:
1377 		if (st->flags & ST_PER_ACTION) {
1378 			if (number > 0) {
1379 				st->flags &= ~ST_PER_ACTION;
1380 				return EIO;
1381 			} else if (number < 0) {
1382 				if (st->flags & ST_AT_FILEMARK) {
1383 					/*
1384 					 * Handling of ST_AT_FILEMARK
1385 					 * in st_space will fill in the
1386 					 * right file mark count.
1387 					 */
1388 					error = st_space(st, 0, SP_FILEMARKS,
1389 						flags);
1390 					if (error)
1391 						return error;
1392 				}
1393 				if (st->flags & ST_BLANK_READ) {
1394 					st->flags &= ~ST_BLANK_READ;
1395 					return EIO;
1396 				}
1397 				st->flags &= ~ST_EIO_PENDING;
1398 			}
1399 		}
1400 		break;
1401 	case SP_FILEMARKS:
1402 		if (st->flags & ST_EIO_PENDING) {
1403 			if (number > 0) {
1404 				/* pretend we just discovered the error */
1405 				st->flags &= ~ST_EIO_PENDING;
1406 				return EIO;
1407 			} else if (number < 0) {
1408 				/* back away from the error */
1409 				st->flags &= ~ST_EIO_PENDING;
1410 			}
1411 		}
1412 		if (st->flags & ST_AT_FILEMARK) {
1413 			st->flags &= ~ST_AT_FILEMARK;
1414 			number--;
1415 		}
1416 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1417 			/* back away from unwritten tape */
1418 			st->flags &= ~ST_BLANK_READ;
1419 			number++;	/* XXX dubious */
1420 		}
1421 		break;
1422 	case SP_EOM:
1423 		if (st->flags & ST_EIO_PENDING) {
1424 			/* pretend we just discovered the error */
1425 			st->flags &= ~ST_EIO_PENDING;
1426 			return EIO;
1427 		}
1428 		if (st->flags & ST_AT_FILEMARK)
1429 			st->flags &= ~ST_AT_FILEMARK;
1430 		break;
1431 	}
1432 	if (number == 0)
1433 		return 0;
1434 
1435 	bzero(&cmd, sizeof(cmd));
1436 	cmd.opcode = SPACE;
1437 	cmd.byte2 = what;
1438 	lto3b(number, cmd.number);
1439 
1440 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1441 	    sizeof(cmd), 0, 0, 0, 900000, NULL, flags);
1442 }
1443 
1444 /*
1445  * write N filemarks
1446  */
1447 int
1448 st_write_filemarks(st, number, flags)
1449 	struct st_softc *st;
1450 	int flags;
1451 	int number;
1452 {
1453 	struct scsi_write_filemarks cmd;
1454 
1455 	/*
1456 	 * It's hard to write a negative number of file marks.
1457 	 * Don't try.
1458 	 */
1459 	if (number < 0)
1460 		return EINVAL;
1461 	switch (number) {
1462 	case 0:		/* really a command to sync the drive's buffers */
1463 		break;
1464 	case 1:
1465 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1466 			st->flags &= ~ST_WRITTEN;
1467 		else
1468 			st->flags |= ST_FM_WRITTEN;
1469 		st->flags &= ~ST_PER_ACTION;
1470 		break;
1471 	default:
1472 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1473 	}
1474 
1475 	bzero(&cmd, sizeof(cmd));
1476 	cmd.opcode = WRITE_FILEMARKS;
1477 	lto3b(number, cmd.number);
1478 
1479 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1480 	    sizeof(cmd), 0, 0, 0, 100000, NULL, flags);
1481 }
1482 
1483 /*
1484  * Make sure the right number of file marks is on tape if the
1485  * tape has been written.  If the position argument is true,
1486  * leave the tape positioned where it was originally.
1487  *
1488  * nmarks returns the number of marks to skip (or, if position
1489  * true, which were skipped) to get back original position.
1490  */
1491 int
1492 st_check_eod(st, position, nmarks, flags)
1493 	struct st_softc *st;
1494 	boolean position;
1495 	int *nmarks;
1496 	int flags;
1497 {
1498 	int error;
1499 
1500 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1501 	default:
1502 		*nmarks = 0;
1503 		return 0;
1504 	case ST_WRITTEN:
1505 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1506 		*nmarks = 1;
1507 		break;
1508 	case ST_WRITTEN | ST_2FM_AT_EOD:
1509 		*nmarks = 2;
1510 	}
1511 	error = st_write_filemarks(st, *nmarks, flags);
1512 	if (position && !error)
1513 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1514 	return error;
1515 }
1516 
1517 /*
1518  * load/unload/retension
1519  */
1520 int
1521 st_load(st, type, flags)
1522 	struct st_softc *st;
1523 	u_int type;
1524 	int flags;
1525 {
1526 	struct scsi_load cmd;
1527 
1528 	if (type != LD_LOAD) {
1529 		int error;
1530 		int nmarks;
1531 
1532 		error = st_check_eod(st, FALSE, &nmarks, flags);
1533 		if (error)
1534 			return error;
1535 	}
1536 	if (st->quirks & ST_Q_IGNORE_LOADS)
1537 		return 0;
1538 
1539 	bzero(&cmd, sizeof(cmd));
1540 	cmd.opcode = LOAD;
1541 	cmd.how = type;
1542 
1543 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1544 	    sizeof(cmd), 0, 0, ST_RETRIES, 300000, NULL, flags);
1545 }
1546 
1547 /*
1548  *  Rewind the device
1549  */
1550 int
1551 st_rewind(st, immediate, flags)
1552 	struct st_softc *st;
1553 	u_int immediate;
1554 	int flags;
1555 {
1556 	struct scsi_rewind cmd;
1557 	int error;
1558 	int nmarks;
1559 
1560 	error = st_check_eod(st, FALSE, &nmarks, flags);
1561 	if (error)
1562 		return error;
1563 	st->flags &= ~ST_PER_ACTION;
1564 
1565 	bzero(&cmd, sizeof(cmd));
1566 	cmd.opcode = REWIND;
1567 	cmd.byte2 = immediate;
1568 
1569 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1570 	    sizeof(cmd), 0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL,
1571 	    flags);
1572 }
1573 
1574 /*
1575  * Look at the returned sense and act on the error and detirmine
1576  * The unix error number to pass back... (0 = report no error)
1577  *                            (-1 = continue processing)
1578  */
1579 int
1580 st_interpret_sense(xs)
1581 	struct scsi_xfer *xs;
1582 {
1583 	struct scsi_link *sc_link = xs->sc_link;
1584 	struct scsi_sense_data *sense = &xs->sense;
1585 	struct buf *bp = xs->bp;
1586 	struct st_softc *st = sc_link->device_softc;
1587 	u_int8_t key;
1588 	u_int32_t info;
1589 
1590 	/*
1591 	 * Get the sense fields and work out what code
1592 	 */
1593 	if (sense->error_code & SSD_ERRCODE_VALID) {
1594 		bcopy(sense->extended_info, &info, sizeof info);
1595 		info = ntohl(info);
1596 	} else
1597 		info = xs->datalen;	/* bad choice if fixed blocks */
1598 	if ((sense->error_code & SSD_ERRCODE) != 0x70)
1599 		return -1;	/* let the generic code handle it */
1600 	if (st->flags & ST_FIXEDBLOCKS) {
1601 		xs->resid = info * st->blksize;
1602 		if (sense->extended_flags & SSD_EOM) {
1603 			st->flags |= ST_EIO_PENDING;
1604 			if (bp)
1605 				bp->b_resid = xs->resid;
1606 		}
1607 		if (sense->extended_flags & SSD_FILEMARK) {
1608 			st->flags |= ST_AT_FILEMARK;
1609 			if (bp)
1610 				bp->b_resid = xs->resid;
1611 		}
1612 		if (sense->extended_flags & SSD_ILI) {
1613 			st->flags |= ST_EIO_PENDING;
1614 			if (bp)
1615 				bp->b_resid = xs->resid;
1616 			if (sense->error_code & SSD_ERRCODE_VALID &&
1617 			    (xs->flags & SCSI_SILENT) == 0)
1618 				printf("%s: block wrong size, %d blocks residual\n",
1619 				    st->sc_dev.dv_xname, info);
1620 
1621 			/*
1622 			 * This quirk code helps the drive read
1623 			 * the first tape block, regardless of
1624 			 * format.  That is required for these
1625 			 * drives to return proper MODE SENSE
1626 			 * information.
1627 			 */
1628 			if ((st->quirks & ST_Q_SENSE_HELP) &&
1629 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
1630 				st->blksize -= 512;
1631 		}
1632 		/*
1633 		 * If no data was tranfered, do it immediatly
1634 		 */
1635 		if (xs->resid >= xs->datalen) {
1636 			if (st->flags & ST_EIO_PENDING)
1637 				return EIO;
1638 			if (st->flags & ST_AT_FILEMARK) {
1639 				if (bp)
1640 					bp->b_resid = xs->resid;
1641 				return 0;
1642 			}
1643 		}
1644 	} else {		/* must be variable mode */
1645 		xs->resid = xs->datalen;	/* to be sure */
1646 		if (sense->extended_flags & SSD_EOM)
1647 			return EIO;
1648 		if (sense->extended_flags & SSD_FILEMARK) {
1649 			if (bp)
1650 				bp->b_resid = bp->b_bcount;
1651 			return 0;
1652 		}
1653 		if (sense->extended_flags & SSD_ILI) {
1654 			if (info < 0) {
1655 				/*
1656 				 * the record was bigger than the read
1657 				 */
1658 				if ((xs->flags & SCSI_SILENT) == 0)
1659 					printf("%s: %d-byte record too big\n",
1660 					    st->sc_dev.dv_xname,
1661 					    xs->datalen - info);
1662 				return EIO;
1663 			}
1664 			xs->resid = info;
1665 			if (bp)
1666 				bp->b_resid = info;
1667 		}
1668 	}
1669 	key = sense->extended_flags & SSD_KEY;
1670 
1671 	if (key == 0x8) {
1672 		/*
1673 		 * This quirk code helps the drive read the
1674 		 * first tape block, regardless of format.  That
1675 		 * is required for these drives to return proper
1676 		 * MODE SENSE information.
1677 		 */
1678 		if ((st->quirks & ST_Q_SENSE_HELP) &&
1679 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
1680 			/* still starting */
1681 			st->blksize -= 512;
1682 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
1683 			st->flags |= ST_BLANK_READ;
1684 			xs->resid = xs->datalen;
1685 			if (bp) {
1686 				bp->b_resid = xs->resid;
1687 				/* return an EOF */
1688 			}
1689 			return 0;
1690 		}
1691 	}
1692 	return -1;		/* let the default/generic handler handle it */
1693 }
1694 
1695 /*
1696  * The quirk here is that the drive returns some value to st_mode_sense
1697  * incorrectly until the tape has actually passed by the head.
1698  *
1699  * The method is to set the drive to large fixed-block state (user-specified
1700  * density and 1024-byte blocks), then read and rewind to get it to sense the
1701  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
1702  * work, as a last resort, try variable- length blocks.  The result will be
1703  * the ability to do an accurate st_mode_sense.
1704  *
1705  * We know we can do a rewind because we just did a load, which implies rewind.
1706  * Rewind seems preferable to space backward if we have a virgin tape.
1707  *
1708  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
1709  * error processing, both part of st_interpret_sense.
1710  */
1711 int
1712 st_touch_tape(st)
1713 	struct st_softc *st;
1714 {
1715 	char *buf;
1716 	int readsize;
1717 	int error;
1718 
1719 	buf = malloc(1024, M_TEMP, M_NOWAIT);
1720 	if (!buf)
1721 		return ENOMEM;
1722 
1723 	if (error = st_mode_sense(st, 0))
1724 		goto bad;
1725 	st->blksize = 1024;
1726 	do {
1727 		switch (st->blksize) {
1728 		case 512:
1729 		case 1024:
1730 			readsize = st->blksize;
1731 			st->flags |= ST_FIXEDBLOCKS;
1732 			break;
1733 		default:
1734 			readsize = 1;
1735 			st->flags &= ~ST_FIXEDBLOCKS;
1736 		}
1737 		if (error = st_mode_select(st, 0))
1738 			goto bad;
1739 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
1740 		if (error = st_rewind(st, 0, 0)) {
1741 bad:			free(buf, M_TEMP);
1742 			return error;
1743 		}
1744 	} while (readsize != 1 && readsize > st->blksize);
1745 
1746 	free(buf, M_TEMP);
1747 	return 0;
1748 }
1749 
1750 int
1751 stdump()
1752 {
1753 
1754 	/* Not implemented. */
1755 	return EINVAL;
1756 }
1757