xref: /netbsd-src/sys/dev/scsipi/st.c (revision edfa83365254b6d7c6cdaa0d30b214319daeee7f)
1 /*	$NetBSD: st.c,v 1.46 1994/12/30 05:23:49 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 	 "ARCHIVE ", "VIPER 150  21247", "",     0, 12, {
149 		0, 0, 0,				/* minor 0-3 */
150 		0, 0, QIC_150,				/* minor 4-7 */
151 		0, 0, QIC_120,				/* minor 8-11 */
152 		0, 0, QIC_24				/* minor 12-15 */
153 	}},
154 	{T_SEQUENTIAL, T_REMOV,
155 	 "WANGTEK ", "5525ES SCSI REV7", "",     0, 0, {
156 		0, 0, 0,				/* minor 0-3 */
157 		ST_Q_BLKSIZE, 0, QIC_525,		/* minor 4-7 */
158 		0, 0, QIC_150,				/* minor 8-11 */
159 		0, 0, QIC_120				/* minor 12-15 */
160 	}},
161 	{T_SEQUENTIAL, T_REMOV,
162 	 "WangDAT ", "Model 1300      ", "",     0, 0, {
163 		0, 0, 0,				/* minor 0-3 */
164 		ST_Q_FORCE_BLKSIZE, 512, DDS,		/* minor 4-7 */
165 		ST_Q_FORCE_BLKSIZE, 1024, DDS,		/* minor 8-11 */
166 		ST_Q_FORCE_BLKSIZE, 0, DDS		/* minor 12-15 */
167 	}},
168 #if 0
169 	{T_SEQUENTIAL, T_REMOV,
170 	 "EXABYTE ", "EXB-8200        ", "",     0, 12, {
171 		0, 0, 0,				/* minor 0-3 */
172 		0, 0, 0,				/* minor 4-7 */
173 		0, 0, 0,				/* minor 8-11 */
174 		0, 0, 0					/* minor 12-15 */
175 	}},
176 #endif
177 };
178 
179 #define NOEJECT 0
180 #define EJECT 1
181 
182 struct st_softc {
183 	struct device sc_dev;
184 /*--------------------present operating parameters, flags etc.----------------*/
185 	int flags;		/* see below                          */
186 	u_int quirks;		/* quirks for the open mode           */
187 	int blksize;		/* blksize we are using                */
188 	u_int8_t density;	/* present density                    */
189 	u_int page_0_size;	/* size of page 0 data		      */
190 	u_int last_dsty;	/* last density opened               */
191 /*--------------------device/scsi parameters----------------------------------*/
192 	struct scsi_link *sc_link;	/* our link to the adpter etc.        */
193 /*--------------------parameters reported by the device ----------------------*/
194 	int blkmin;		/* min blk size                       */
195 	int blkmax;		/* max blk size                       */
196 	struct quirkdata *quirkdata;	/* if we have a rogue entry           */
197 /*--------------------parameters reported by the device for this media--------*/
198 	u_long numblks;		/* nominal blocks capacity            */
199 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
200 	u_int8_t media_density;	/* this is what it said when asked    */
201 /*--------------------quirks for the whole drive------------------------------*/
202 	u_int drive_quirks;	/* quirks of this drive               */
203 /*--------------------How we should set up when opening each minor device----*/
204 	struct modes modes[4];	/* plus more for each mode            */
205 	u_int8_t  modeflags[4];	/* flags for the modes                */
206 #define DENSITY_SET_BY_USER	0x01
207 #define DENSITY_SET_BY_QUIRK	0x02
208 #define BLKSIZE_SET_BY_USER	0x04
209 #define BLKSIZE_SET_BY_QUIRK	0x08
210 /*--------------------storage for sense data returned by the drive------------*/
211 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
212 						 * additional sense data needed
213 						 * for mode sense/select.
214 						 */
215 	struct buf buf_queue;		/* the queue of pending IO operations */
216 };
217 
218 int stmatch __P((struct device *, void *, void *));
219 void stattach __P((struct device *, struct device *, void *));
220 
221 struct cfdriver stcd = {
222 	NULL, "st", stmatch, stattach, DV_TAPE, sizeof(struct st_softc)
223 };
224 
225 int	st_space __P((struct st_softc *, int number, u_int what, int flags));
226 int	st_rewind __P((struct st_softc *, u_int immediate, int flags));
227 int	st_mode_sense __P((struct st_softc *, int flags));
228 int	st_decide_mode __P((struct st_softc *, boolean first_read));
229 int	st_read_block_limits __P((struct st_softc *, int flags));
230 int	st_touch_tape __P((struct st_softc *));
231 int	st_write_filemarks __P((struct st_softc *, int number, int flags));
232 int	st_load __P((struct st_softc *, u_int type, int flags));
233 int	st_mode_select __P((struct st_softc *, int flags));
234 void    ststrategy();
235 void    stminphys();
236 int	st_check_eod();
237 void    ststart();
238 void	st_unmount();
239 int	st_mount_tape();
240 void	st_loadquirks();
241 void	st_identify_drive();
242 int	st_interpret_sense();
243 
244 struct scsi_device st_switch = {
245 	st_interpret_sense,
246 	ststart,
247 	NULL,
248 	NULL,
249 };
250 
251 #define	ST_INFO_VALID	0x0001
252 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
253 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
254 #define	ST_FIXEDBLOCKS	0x0008
255 #define	ST_AT_FILEMARK	0x0010
256 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
257 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode              */
258 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
259 #define	ST_FM_WRITTEN	0x0100	/*
260 				 * EOF file mark written  -- used with
261 				 * ~ST_WRITTEN to indicate that multiple file
262 				 * marks have been written
263 				 */
264 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
265 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
266 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
267 
268 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
269 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN | \
270 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN | \
271 			 ST_2FM_AT_EOD | ST_PER_ACTION)
272 
273 struct scsi_inquiry_pattern st_patterns[] = {
274 	{T_SEQUENTIAL, T_REMOV,
275 	 "",         "",                 ""},
276 };
277 
278 int
279 stmatch(parent, match, aux)
280 	struct device *parent;
281 	void *match, *aux;
282 {
283 	struct cfdata *cf = match;
284 	struct scsibus_attach_args *sa = aux;
285 	int priority;
286 
287 	(void)scsi_inqmatch(sa->sa_inqbuf,
288 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
289 	    sizeof(st_patterns[0]), &priority);
290 	return (priority);
291 }
292 
293 /*
294  * The routine called by the low level scsi routine when it discovers
295  * A device suitable for this driver
296  */
297 void
298 stattach(parent, self, aux)
299 	struct device *parent, *self;
300 	void *aux;
301 {
302 	struct st_softc *st = (void *)self;
303 	struct scsibus_attach_args *sa = aux;
304 	struct scsi_link *sc_link = sa->sa_sc_link;
305 
306 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
307 
308 	/*
309 	 * Store information needed to contact our base driver
310 	 */
311 	st->sc_link = sc_link;
312 	sc_link->device = &st_switch;
313 	sc_link->device_softc = st;
314 	sc_link->openings = 1;
315 
316 	/*
317 	 * Check if the drive is a known criminal and take
318 	 * Any steps needed to bring it into line
319 	 */
320 	st_identify_drive(st, sa->sa_inqbuf);
321 
322 	/*
323 	 * Use the subdriver to request information regarding
324 	 * the drive. We cannot use interrupts yet, so the
325 	 * request must specify this.
326 	 */
327 	printf(": %s", st->quirkdata ? "rogue, " : "");
328 	if (scsi_test_unit_ready(sc_link,
329 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
330 	    st_mode_sense(st,
331 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
332 		printf("drive empty\n");
333 	else {
334 		printf("density code 0x%x, ", st->media_density);
335 		if (st->media_blksize > 0)
336 			printf("%d-byte", st->media_blksize);
337 		else
338 			printf("variable");
339 		printf(" blocks, write-%s\n",
340 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
341 	}
342 
343 	/*
344 	 * Set up the buf queue for this device
345 	 */
346 	st->buf_queue.b_active = 0;
347 	st->buf_queue.b_actf = 0;
348 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
349 }
350 
351 /*
352  * Use the inquiry routine in 'scsi_base' to get drive info so we can
353  * Further tailor our behaviour.
354  */
355 void
356 st_identify_drive(st, inqbuf)
357 	struct st_softc *st;
358 	struct scsi_inquiry_data *inqbuf;
359 {
360 	struct st_quirk_inquiry_pattern *finger;
361 	int priority;
362 
363 	finger = (struct st_quirk_inquiry_pattern *)scsi_inqmatch(inqbuf,
364 	    (caddr_t)st_quirk_patterns,
365 	    sizeof(st_quirk_patterns)/sizeof(st_quirk_patterns[0]),
366 	    sizeof(st_quirk_patterns[0]), &priority);
367 	if (priority != 0) {
368 		st->quirkdata = &finger->quirkdata;
369 		st->drive_quirks = finger->quirkdata.quirks;
370 		st->quirks = finger->quirkdata.quirks;	/* start value */
371 		st->page_0_size = finger->quirkdata.page_0_size;
372 		st_loadquirks(st);
373 	}
374 }
375 
376 /*
377  * initialise the subdevices to the default (QUIRK) state.
378  * this will remove any setting made by the system operator or previous
379  * operations.
380  */
381 void
382 st_loadquirks(st)
383 	struct st_softc *st;
384 {
385 	int i;
386 	struct	modes *mode;
387 	struct	modes *mode2;
388 
389 	mode = st->quirkdata->modes;
390 	mode2 = st->modes;
391 	for (i = 0; i < 4; i++) {
392 		bzero(mode2, sizeof(struct modes));
393 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
394 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
395 		    DENSITY_SET_BY_USER);
396 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
397 			mode2->blksize = mode->blksize;
398 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
399 		}
400 		if (mode->density) {
401 			mode2->density = mode->density;
402 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
403 		}
404 		mode++;
405 		mode2++;
406 	}
407 }
408 
409 /*
410  * open the device.
411  */
412 int
413 stopen(dev, flags)
414 	dev_t dev;
415 	int flags;
416 {
417 	int unit;
418 	u_int mode, dsty;
419 	int error = 0;
420 	struct st_softc *st;
421 	struct scsi_link *sc_link;
422 
423 	unit = STUNIT(dev);
424 	if (unit >= stcd.cd_ndevs)
425 		return ENXIO;
426 	st = stcd.cd_devs[unit];
427 	if (!st)
428 		return ENXIO;
429 
430 	mode = STMODE(dev);
431 	dsty = STDSTY(dev);
432 	sc_link = st->sc_link;
433 
434 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
435 	    unit, stcd.cd_ndevs));
436 
437 	/*
438 	 * Only allow one at a time
439 	 */
440 	if (sc_link->flags & SDEV_OPEN) {
441 		printf("%s: already open\n", st->sc_dev.dv_xname);
442 		return EBUSY;
443 	}
444 
445 	/*
446 	 * Catch any unit attention errors.
447 	 */
448 	if (error = scsi_test_unit_ready(sc_link,
449 	    SCSI_IGNORE_MEDIA_CHANGE | (mode == CTLMODE ? SCSI_IGNORE_NOT_READY : 0)))
450 		goto bad;
451 
452 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
453 
454 	/*
455 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
456 	 * then the device has been opened to set defaults
457 	 * This mode does NOT ALLOW I/O, only ioctls
458 	 */
459 	if (mode == CTLMODE)
460 		return 0;
461 
462 	/*
463 	 * if it's a different mode, or if the media has been
464 	 * invalidated, unmount the tape from the previous
465 	 * session but continue with open processing
466 	 */
467 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
468 		st_unmount(st, NOEJECT);
469 
470 	/*
471 	 * If we are not mounted, then we should start a new
472 	 * mount session.
473 	 */
474 	if (!(st->flags & ST_MOUNTED)) {
475 		st_mount_tape(dev, flags);
476 		st->last_dsty = dsty;
477 	}
478 
479 	/*
480 	 * Make sure that a tape opened in write-only mode will have
481 	 * file marks written on it when closed, even if not written to.
482 	 * This is for SUN compatibility
483 	 */
484 	if ((flags & O_ACCMODE) == FWRITE)
485 		st->flags |= ST_WRITTEN;
486 
487 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
488 	return 0;
489 
490 bad:
491 	st_unmount(st, NOEJECT);
492 	sc_link->flags &= ~SDEV_OPEN;
493 	return error;
494 }
495 
496 /*
497  * close the device.. only called if we are the LAST
498  * occurence of an open device
499  */
500 int
501 stclose(dev)
502 	dev_t dev;
503 {
504 	struct st_softc *st = stcd.cd_devs[STUNIT(dev)];
505 
506 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
507 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
508 		st_write_filemarks(st, 1, 0);
509 	switch (STMODE(dev)) {
510 	case 0:
511 	case 3:		/* for now */
512 		st_unmount(st, NOEJECT);
513 		break;
514 	case 1:
515 		/* leave mounted unless media seems to have been removed */
516 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
517 			st_unmount(st, NOEJECT);
518 		break;
519 	case 2:
520 		st_unmount(st, EJECT);
521 		break;
522 	}
523 	st->sc_link->flags &= ~SDEV_OPEN;
524 
525 	return 0;
526 }
527 
528 /*
529  * Start a new mount session.
530  * Copy in all the default parameters from the selected device mode.
531  * and try guess any that seem to be defaulted.
532  */
533 int
534 st_mount_tape(dev, flags)
535 	dev_t dev;
536 	int flags;
537 {
538 	int unit;
539 	u_int mode, dsty;
540 	struct st_softc *st;
541 	struct scsi_link *sc_link;
542 	int error = 0;
543 
544 	unit = STUNIT(dev);
545 	mode = STMODE(dev);
546 	dsty = STDSTY(dev);
547 	st = stcd.cd_devs[unit];
548 	sc_link = st->sc_link;
549 
550 	if (st->flags & ST_MOUNTED)
551 		return 0;
552 
553 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
554 	st->flags |= ST_NEW_MOUNT;
555 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
556 	/*
557 	 * If the media is new, then make sure we give it a chance to
558 	 * to do a 'load' instruction.  (We assume it is new.)
559 	 */
560 	if (error = st_load(st, LD_LOAD, 0))
561 		return error;
562 	/*
563 	 * Throw another dummy instruction to catch
564 	 * 'Unit attention' errors. Some drives appear to give
565 	 * these after doing a Load instruction.
566 	 * (noteably some DAT drives)
567 	 */
568 	scsi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
569 
570 	/*
571 	 * Some devices can't tell you much until they have been
572 	 * asked to look at the media. This quirk does this.
573 	 */
574 	if (st->quirks & ST_Q_SENSE_HELP)
575 		if (error = st_touch_tape(st))
576 			return error;
577 	/*
578 	 * Load the physical device parameters
579 	 * loads: blkmin, blkmax
580 	 */
581 	if (error = st_read_block_limits(st, 0))
582 		return error;
583 	/*
584 	 * Load the media dependent parameters
585 	 * includes: media_blksize,media_density,numblks
586 	 * As we have a tape in, it should be reflected here.
587 	 * If not you may need the "quirk" above.
588 	 */
589 	if (error = st_mode_sense(st, 0))
590 		return error;
591 	/*
592 	 * If we have gained a permanent density from somewhere,
593 	 * then use it in preference to the one supplied by
594 	 * default by the driver.
595 	 */
596 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
597 		st->density = st->modes[dsty].density;
598 	else
599 		st->density = st->media_density;
600 	/*
601 	 * If we have gained a permanent blocksize
602 	 * then use it in preference to the one supplied by
603 	 * default by the driver.
604 	 */
605 	st->flags &= ~ST_FIXEDBLOCKS;
606 	if (st->modeflags[dsty] & (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
607 		st->blksize = st->modes[dsty].blksize;
608 		if (st->blksize)
609 			st->flags |= ST_FIXEDBLOCKS;
610 	} else {
611 		if (error = st_decide_mode(st, FALSE))
612 			return error;
613 	}
614 	if (error = st_mode_select(st, 0)) {
615 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
616 		return error;
617 	}
618 	scsi_prevent(sc_link, PR_PREVENT,
619 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
620 	st->flags &= ~ST_NEW_MOUNT;
621 	st->flags |= ST_MOUNTED;
622 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
623 
624 	return 0;
625 }
626 
627 /*
628  * End the present mount session.
629  * Rewind, and optionally eject the tape.
630  * Reset various flags to indicate that all new
631  * operations require another mount operation
632  */
633 void
634 st_unmount(st, eject)
635 	struct st_softc *st;
636 	boolean eject;
637 {
638 	struct scsi_link *sc_link = st->sc_link;
639 	int nmarks;
640 
641 	if (!(st->flags & ST_MOUNTED))
642 		return;
643 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
644 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
645 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
646 	scsi_prevent(sc_link, PR_ALLOW,
647 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
648 	if (eject)
649 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
650 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
651 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
652 }
653 
654 /*
655  * Given all we know about the device, media, mode, 'quirks' and
656  * initial operation, make a decision as to how we should be set
657  * to run (regarding blocking and EOD marks)
658  */
659 int
660 st_decide_mode(st, first_read)
661 	struct st_softc *st;
662 	boolean	first_read;
663 {
664 #ifdef SCSIDEBUG
665 	struct scsi_link *sc_link = st->sc_link;
666 #endif
667 
668 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
669 
670 	/*
671 	 * If the drive can only handle fixed-length blocks and only at
672 	 * one size, perhaps we should just do that.
673 	 */
674 	if (st->blkmin && (st->blkmin == st->blkmax)) {
675 		st->flags |= ST_FIXEDBLOCKS;
676 		st->blksize = st->blkmin;
677 		SC_DEBUG(sc_link, SDEV_DB3,
678 		    ("blkmin == blkmax of %d\n", st->blkmin));
679 		goto done;
680 	}
681 	/*
682 	 * If the tape density mandates (or even suggests) use of fixed
683 	 * or variable-length blocks, comply.
684 	 */
685 	switch (st->density) {
686 	case HALFINCH_800:
687 	case HALFINCH_1600:
688 	case HALFINCH_6250:
689 	case DDS:
690 		st->flags &= ~ST_FIXEDBLOCKS;
691 		st->blksize = 0;
692 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
693 		goto done;
694 	case QIC_11:
695 	case QIC_24:
696 	case QIC_120:
697 	case QIC_150:
698 	case QIC_525:
699 	case QIC_1320:
700 		st->flags |= ST_FIXEDBLOCKS;
701 		if (st->media_blksize > 0)
702 			st->blksize = st->media_blksize;
703 		else
704 			st->blksize = DEF_FIXED_BSIZE;
705 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
706 		goto done;
707 	}
708 	/*
709 	 * If we're about to read the tape, perhaps we should choose
710 	 * fixed or variable-length blocks and block size according to
711 	 * what the drive found on the tape.
712 	 */
713 	if (first_read &&
714 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
715 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
716 	    (st->media_blksize == 1024))) {
717 		if (st->media_blksize > 0)
718 			st->flags |= ST_FIXEDBLOCKS;
719 		else
720 			st->flags &= ~ST_FIXEDBLOCKS;
721 		st->blksize = st->media_blksize;
722 		SC_DEBUG(sc_link, SDEV_DB3,
723 		    ("Used media_blksize of %d\n", st->media_blksize));
724 		goto done;
725 	}
726 	/*
727 	 * We're getting no hints from any direction.  Choose variable-
728 	 * length blocks arbitrarily.
729 	 */
730 	st->flags &= ~ST_FIXEDBLOCKS;
731 	st->blksize = 0;
732 	SC_DEBUG(sc_link, SDEV_DB3,
733 	    ("Give up and default to variable mode\n"));
734 
735 done:
736 	/*
737 	 * Decide whether or not to write two file marks to signify end-
738 	 * of-data.  Make the decision as a function of density.  If
739 	 * the decision is not to use a second file mark, the SCSI BLANK
740 	 * CHECK condition code will be recognized as end-of-data when
741 	 * first read.
742 	 * (I think this should be a by-product of fixed/variable..julian)
743 	 */
744 	switch (st->density) {
745 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
746 	case QIC_11:
747 	case QIC_24:
748 	case QIC_120:
749 	case QIC_150:
750 	case QIC_525:
751 	case QIC_1320:
752 		st->flags &= ~ST_2FM_AT_EOD;
753 		break;
754 	default:
755 		st->flags |= ST_2FM_AT_EOD;
756 	}
757 	return 0;
758 }
759 
760 /*
761  * trim the size of the transfer if needed,
762  * called by physio
763  * basically the smaller of our min and the scsi driver's
764  * minphys
765  */
766 void
767 stminphys(bp)
768 	struct buf *bp;
769 {
770 	register struct st_softc *st = stcd.cd_devs[STUNIT(bp->b_dev)];
771 
772 	(st->sc_link->adapter->scsi_minphys) (bp);
773 }
774 
775 /*
776  * Actually translate the requested transfer into
777  * one the physical driver can understand
778  * The transfer is described by a buf and will include
779  * only one physical transfer.
780  */
781 void
782 ststrategy(bp)
783 	struct buf *bp;
784 {
785 	struct st_softc *st = stcd.cd_devs[STUNIT(bp->b_dev)];
786 	struct buf *dp;
787 	int opri;
788 
789 	SC_DEBUG(st->sc_link, SDEV_DB1,
790 	    ("ststrategy %d bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
791 	/*
792 	 * If it's a null transfer, return immediatly
793 	 */
794 	if (bp->b_bcount == 0)
795 		goto done;
796 	/*
797 	 * Odd sized request on fixed drives are verboten
798 	 */
799 	if (st->flags & ST_FIXEDBLOCKS) {
800 		if (bp->b_bcount % st->blksize) {
801 			printf("%s: bad request, must be multiple of %d\n",
802 			    st->sc_dev.dv_xname, st->blksize);
803 			bp->b_error = EIO;
804 			goto bad;
805 		}
806 	}
807 	/*
808 	 * as are out-of-range requests on variable drives.
809 	 */
810 	else if (bp->b_bcount < st->blkmin ||
811 		 (st->blkmax && bp->b_bcount > st->blkmax)) {
812 		printf("%s: bad request, must be between %d and %d\n",
813 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
814 		bp->b_error = EIO;
815 		goto bad;
816 	}
817 	stminphys(bp);
818 	opri = splbio();
819 
820 	/*
821 	 * Place it in the queue of activities for this tape
822 	 * at the end (a bit silly because we only have on user..
823 	 * (but it could fork()))
824 	 */
825 	dp = &st->buf_queue;
826 	bp->b_actf = NULL;
827 	bp->b_actb = dp->b_actb;
828 	*dp->b_actb = bp;
829 	dp->b_actb = &bp->b_actf;
830 
831 	/*
832 	 * Tell the device to get going on the transfer if it's
833 	 * not doing anything, otherwise just wait for completion
834 	 * (All a bit silly if we're only allowing 1 open but..)
835 	 */
836 	ststart(st);
837 
838 	splx(opri);
839 	return;
840 bad:
841 	bp->b_flags |= B_ERROR;
842 done:
843 	/*
844 	 * Correctly set the buf to indicate a completed xfer
845 	 */
846 	iodone(bp);
847 	return;
848 }
849 
850 /*
851  * ststart looks to see if there is a buf waiting for the device
852  * and that the device is not already busy. If both are true,
853  * It dequeues the buf and creates a scsi command to perform the
854  * transfer required. The transfer request will call scsi_done
855  * on completion, which will in turn call this routine again
856  * so that the next queued transfer is performed.
857  * The bufs are queued by the strategy routine (ststrategy)
858  *
859  * This routine is also called after other non-queued requests
860  * have been made of the scsi driver, to ensure that the queue
861  * continues to be drained.
862  * ststart() is called at splbio
863  */
864 void
865 ststart(st)
866 	struct st_softc *st;
867 {
868 	struct scsi_link *sc_link = st->sc_link;
869 	register struct buf *bp, *dp;
870 	struct scsi_rw_tape cmd;
871 	int flags;
872 
873 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
874 	/*
875 	 * See if there is a buf to do and we are not already
876 	 * doing one
877 	 */
878 	while (sc_link->openings > 0) {
879 		/* if a special awaits, let it proceed first */
880 		if (sc_link->flags & SDEV_WAITING) {
881 			sc_link->flags &= ~SDEV_WAITING;
882 			wakeup((caddr_t)sc_link);
883 			return;
884 		}
885 
886 		bp = st->buf_queue.b_actf;
887 		if (!bp)
888 			return;	/* no work to bother with */
889 		if (dp = bp->b_actf)
890 			dp->b_actb = bp->b_actb;
891 		else
892 			st->buf_queue.b_actb = bp->b_actb;
893 		*bp->b_actb = dp;
894 
895 		/*
896 		 * if the device has been unmounted byt the user
897 		 * then throw away all requests until done
898 		 */
899 		if (!(st->flags & ST_MOUNTED) ||
900 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
901 			/* make sure that one implies the other.. */
902 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
903 			bp->b_flags |= B_ERROR;
904 			bp->b_error = EIO;
905 			biodone(bp);
906 			continue;
907 		}
908 		/*
909 		 * only FIXEDBLOCK devices have pending operations
910 		 */
911 		if (st->flags & ST_FIXEDBLOCKS) {
912 			/*
913 			 * If we are at a filemark but have not reported it yet
914 			 * then we should report it now
915 			 */
916 			if (st->flags & ST_AT_FILEMARK) {
917 				if ((bp->b_flags & B_READ) == B_WRITE) {
918 					/*
919 					 * Handling of ST_AT_FILEMARK in
920 					 * st_space will fill in the right file
921 					 * mark count.
922 					 * Back up over filemark
923 					 */
924 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
925 						bp->b_flags |= B_ERROR;
926 						bp->b_error = EIO;
927 						biodone(bp);
928 						continue;
929 					}
930 				} else {
931 					bp->b_resid = bp->b_bcount;
932 					bp->b_error = 0;
933 					bp->b_flags &= ~B_ERROR;
934 					st->flags &= ~ST_AT_FILEMARK;
935 					biodone(bp);
936 					continue;	/* seek more work */
937 				}
938 			}
939 			/*
940 			 * If we are at EIO (e.g. EOM) but have not reported it
941 			 * yet then we should report it now
942 			 */
943 			if (st->flags & ST_EIO_PENDING) {
944 				bp->b_resid = bp->b_bcount;
945 				bp->b_error = EIO;
946 				bp->b_flags |= B_ERROR;
947 				st->flags &= ~ST_EIO_PENDING;
948 				biodone(bp);
949 				continue;	/* seek more work */
950 			}
951 		}
952 
953 		/*
954 		 *  Fill out the scsi command
955 		 */
956 		bzero(&cmd, sizeof(cmd));
957 		if ((bp->b_flags & B_READ) == B_WRITE) {
958 			cmd.opcode = WRITE;
959 			st->flags &= ~ST_FM_WRITTEN;
960 			st->flags |= ST_WRITTEN;
961 			flags = SCSI_DATA_OUT;
962 		} else {
963 			cmd.opcode = READ;
964 			flags = SCSI_DATA_IN;
965 		}
966 
967 		/*
968 		 * Handle "fixed-block-mode" tape drives by using the
969 		 * block count instead of the length.
970 		 */
971 		if (st->flags & ST_FIXEDBLOCKS) {
972 			cmd.byte2 |= SRW_FIXED;
973 			lto3b(bp->b_bcount / st->blksize, cmd.len);
974 		} else
975 			lto3b(bp->b_bcount, cmd.len);
976 
977 		/*
978 		 * go ask the adapter to do all this for us
979 		 */
980 		if (scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
981 		    sizeof(cmd), (u_char *) bp->b_data, bp->b_bcount, 0,
982 		    100000, bp, flags | SCSI_NOSLEEP))
983 			printf("%s: not queued\n", st->sc_dev.dv_xname);
984 	} /* go back and see if we can cram more work in.. */
985 }
986 
987 /*
988  * Perform special action on behalf of the user;
989  * knows about the internals of this device
990  */
991 int
992 stioctl(dev, cmd, arg, flag, p)
993 	dev_t dev;
994 	u_long cmd;
995 	caddr_t arg;
996 	int flag;
997 	struct proc *p;
998 {
999 	int error = 0;
1000 	int unit;
1001 	int number, nmarks, dsty;
1002 	int flags;
1003 	struct st_softc *st;
1004 	int hold_blksize;
1005 	u_int8_t hold_density;
1006 	struct mtop *mt = (struct mtop *) arg;
1007 
1008 	/*
1009 	 * Find the device that the user is talking about
1010 	 */
1011 	flags = 0;		/* give error messages, act on errors etc. */
1012 	unit = STUNIT(dev);
1013 	dsty = STDSTY(dev);
1014 	st = stcd.cd_devs[unit];
1015 	hold_blksize = st->blksize;
1016 	hold_density = st->density;
1017 
1018 	switch (cmd) {
1019 
1020 	case MTIOCGET: {
1021 		struct mtget *g = (struct mtget *) arg;
1022 
1023 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1024 		bzero(g, sizeof(struct mtget));
1025 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1026 		g->mt_blksiz = st->blksize;
1027 		g->mt_density = st->density;
1028 		g->mt_mblksiz[0] = st->modes[0].blksize;
1029 		g->mt_mblksiz[1] = st->modes[1].blksize;
1030 		g->mt_mblksiz[2] = st->modes[2].blksize;
1031 		g->mt_mblksiz[3] = st->modes[3].blksize;
1032 		g->mt_mdensity[0] = st->modes[0].density;
1033 		g->mt_mdensity[1] = st->modes[1].density;
1034 		g->mt_mdensity[2] = st->modes[2].density;
1035 		g->mt_mdensity[3] = st->modes[3].density;
1036 		break;
1037 	}
1038 	case MTIOCTOP: {
1039 
1040 		SC_DEBUG(st->sc_link, SDEV_DB1,
1041 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op, mt->mt_count));
1042 
1043 		/* compat: in U*x it is a short */
1044 		number = mt->mt_count;
1045 		switch ((short) (mt->mt_op)) {
1046 		case MTWEOF:	/* write an end-of-file record */
1047 			error = st_write_filemarks(st, number, flags);
1048 			break;
1049 		case MTBSF:	/* backward space file */
1050 			number = -number;
1051 		case MTFSF:	/* forward space file */
1052 			error = st_check_eod(st, FALSE, &nmarks, flags);
1053 			if (!error)
1054 				error = st_space(st, number - nmarks,
1055 				    SP_FILEMARKS, flags);
1056 			break;
1057 		case MTBSR:	/* backward space record */
1058 			number = -number;
1059 		case MTFSR:	/* forward space record */
1060 			error = st_check_eod(st, TRUE, &nmarks, flags);
1061 			if (!error)
1062 				error = st_space(st, number, SP_BLKS, flags);
1063 			break;
1064 		case MTREW:	/* rewind */
1065 			error = st_rewind(st, 0, flags);
1066 			break;
1067 		case MTOFFL:	/* rewind and put the drive offline */
1068 			st_unmount(st, EJECT);
1069 			break;
1070 		case MTNOP:	/* no operation, sets status only */
1071 			break;
1072 		case MTRETEN:	/* retension the tape */
1073 			error = st_load(st, LD_RETENSION, flags);
1074 			if (!error)
1075 				error = st_load(st, LD_LOAD, flags);
1076 			break;
1077 		case MTEOM:	/* forward space to end of media */
1078 			error = st_check_eod(st, FALSE, &nmarks, flags);
1079 			if (!error)
1080 				error = st_space(st, 1, SP_EOM, flags);
1081 			break;
1082 		case MTCACHE:	/* enable controller cache */
1083 		case MTNOCACHE:	/* disable controller cache */
1084 			break;
1085 		case MTSETBSIZ:	/* Set block size for device */
1086 #ifdef	NOTYET
1087 			if (!(st->flags & ST_NEW_MOUNT)) {
1088 				uprintf("re-mount tape before changing blocksize");
1089 				error = EINVAL;
1090 				break;
1091 			}
1092 #endif
1093 			if (number == 0) {
1094 				st->flags &= ~ST_FIXEDBLOCKS;
1095 			} else {
1096 				if ((st->blkmin || st->blkmax) &&
1097 				    (number < st->blkmin ||
1098 				    number > st->blkmax)) {
1099 					error = EINVAL;
1100 					break;
1101 				}
1102 				st->flags |= ST_FIXEDBLOCKS;
1103 			}
1104 			st->blksize = number;
1105 			st->flags |= ST_BLOCK_SET;	/*XXX */
1106 			goto try_new_value;
1107 
1108 		case MTSETDNSTY:	/* Set density for device and mode */
1109 			if (number > SCSI_2_MAX_DENSITY_CODE)
1110 				error = EINVAL;
1111 			else
1112 				st->density = number;
1113 			goto try_new_value;
1114 
1115 		default:
1116 			error = EINVAL;
1117 		}
1118 		break;
1119 	}
1120 	case MTIOCIEOT:
1121 	case MTIOCEEOT:
1122 		break;
1123 	default:
1124 		if (STMODE(dev) == CTLMODE)
1125 			error = scsi_do_ioctl(st->sc_link, dev, cmd, arg, flag, p);
1126 		else
1127 			error = ENOTTY;
1128 		break;
1129 	}
1130 	return error;
1131 /*-----------------------------*/
1132 try_new_value:
1133 	/*
1134 	 * Check that the mode being asked for is aggreeable to the
1135 	 * drive. If not, put it back the way it was.
1136 	 */
1137 	if (error = st_mode_select(st, 0)) {	/* put it back as it was */
1138 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1139 		st->density = hold_density;
1140 		st->blksize = hold_blksize;
1141 		if (st->blksize)
1142 			st->flags |= ST_FIXEDBLOCKS;
1143 		else
1144 			st->flags &= ~ST_FIXEDBLOCKS;
1145 		return error;
1146 	}
1147 	/*
1148 	 * As the drive liked it, if we are setting a new default,
1149 	 * set it into the structures as such.
1150 	 *
1151 	 * The means for deciding this are not finalised yet
1152 	 */
1153 	if (STMODE(dev) == 0x03) {
1154 		/* special mode */
1155 		/* XXX */
1156 		switch ((short) (mt->mt_op)) {
1157 		case MTSETBSIZ:
1158 			st->modes[dsty].blksize = st->blksize;
1159 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1160 			break;
1161 		case MTSETDNSTY:
1162 			st->modes[dsty].density = st->density;
1163 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1164 			break;
1165 		}
1166 	}
1167 	return 0;
1168 }
1169 
1170 /*
1171  * Do a synchronous read.
1172  */
1173 int
1174 st_read(st, buf, size, flags)
1175 	struct st_softc *st;
1176 	int size;
1177 	int flags;
1178 	char *buf;
1179 {
1180 	struct scsi_rw_tape cmd;
1181 
1182 	/*
1183 	 * If it's a null transfer, return immediatly
1184 	 */
1185 	if (size == 0)
1186 		return 0;
1187 	bzero(&cmd, sizeof(cmd));
1188 	cmd.opcode = READ;
1189 	if (st->flags & ST_FIXEDBLOCKS) {
1190 		cmd.byte2 |= SRW_FIXED;
1191 		lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1192 		    cmd.len);
1193 	} else
1194 		lto3b(size, cmd.len);
1195 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1196 	    sizeof(cmd), (u_char *) buf, size, 0, 100000, NULL,
1197 	    flags | SCSI_DATA_IN);
1198 }
1199 
1200 #ifdef	__STDC__
1201 #define b2tol(a)	(((unsigned)(a##_1) << 8) + (unsigned)a##_0)
1202 #else
1203 #define b2tol(a)	(((unsigned)(a/**/_1) << 8) + (unsigned)a/**/_0)
1204 #endif
1205 
1206 /*
1207  * Ask the drive what it's min and max blk sizes are.
1208  */
1209 int
1210 st_read_block_limits(st, flags)
1211 	struct st_softc *st;
1212 	int flags;
1213 {
1214 	struct scsi_block_limits cmd;
1215 	struct scsi_block_limits_data block_limits;
1216 	struct scsi_link *sc_link = st->sc_link;
1217 	int error;
1218 
1219 	/*
1220 	 * First check if we have it all loaded
1221 	 */
1222 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1223 		return 0;
1224 
1225 	/*
1226 	 * do a 'Read Block Limits'
1227 	 */
1228 	bzero(&cmd, sizeof(cmd));
1229 	cmd.opcode = READ_BLOCK_LIMITS;
1230 
1231 	/*
1232 	 * do the command, update the global values
1233 	 */
1234 	if (error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1235 	    sizeof(cmd), (u_char *) &block_limits, sizeof(block_limits),
1236 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN))
1237 		return error;
1238 
1239 	st->blkmin = b2tol(block_limits.min_length);
1240 	st->blkmax = _3btol(&block_limits.max_length_2);
1241 
1242 	SC_DEBUG(sc_link, SDEV_DB3,
1243 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1244 	return 0;
1245 }
1246 
1247 /*
1248  * Get the scsi driver to send a full inquiry to the
1249  * device and use the results to fill out the global
1250  * parameter structure.
1251  *
1252  * called from:
1253  * attach
1254  * open
1255  * ioctl (to reset original blksize)
1256  */
1257 int
1258 st_mode_sense(st, flags)
1259 	struct st_softc *st;
1260 	int flags;
1261 {
1262 	u_int scsi_sense_len;
1263 	int error;
1264 	struct scsi_mode_sense cmd;
1265 	struct scsi_sense {
1266 		struct scsi_mode_header header;
1267 		struct scsi_blk_desc blk_desc;
1268 		u_char sense_data[MAX_PAGE_0_SIZE];
1269 	} scsi_sense;
1270 	struct scsi_link *sc_link = st->sc_link;
1271 
1272 	scsi_sense_len = 12 + st->page_0_size;
1273 
1274 	/*
1275 	 * Set up a mode sense
1276 	 */
1277 	bzero(&cmd, sizeof(cmd));
1278 	cmd.opcode = MODE_SENSE;
1279 	cmd.length = scsi_sense_len;
1280 
1281 	/*
1282 	 * do the command, but we don't need the results
1283 	 * just print them for our interest's sake, if asked,
1284 	 * or if we need it as a template for the mode select
1285 	 * store it away.
1286 	 */
1287 	if (error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1288 	    sizeof(cmd), (u_char *) &scsi_sense, scsi_sense_len,
1289 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN))
1290 		return error;
1291 
1292 	st->numblks = _3btol(scsi_sense.blk_desc.nblocks);
1293 	st->media_blksize = _3btol(scsi_sense.blk_desc.blklen);
1294 	st->media_density = scsi_sense.blk_desc.density;
1295 	if (scsi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1296 		st->flags |= ST_READONLY;
1297 	SC_DEBUG(sc_link, SDEV_DB3,
1298 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1299 	    st->media_density, st->media_blksize,
1300 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1301 	SC_DEBUG(sc_link, SDEV_DB3,
1302 	    ("%sbuffered\n",
1303 	    scsi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1304 	if (st->page_0_size)
1305 		bcopy(scsi_sense.sense_data, st->sense_data, st->page_0_size);
1306 	sc_link->flags |= SDEV_MEDIA_LOADED;
1307 	return 0;
1308 }
1309 
1310 /*
1311  * Send a filled out parameter structure to the drive to
1312  * set it into the desire modes etc.
1313  */
1314 int
1315 st_mode_select(st, flags)
1316 	struct st_softc *st;
1317 	int flags;
1318 {
1319 	u_int scsi_select_len;
1320 	int error;
1321 	struct scsi_mode_select cmd;
1322 	struct scsi_select {
1323 		struct scsi_mode_header header;
1324 		struct scsi_blk_desc blk_desc;
1325 		u_char sense_data[MAX_PAGE_0_SIZE];
1326 	} scsi_select;
1327 	struct scsi_link *sc_link = st->sc_link;
1328 
1329 	scsi_select_len = 12 + st->page_0_size;
1330 
1331 	/*
1332 	 * Set up for a mode select
1333 	 */
1334 	bzero(&cmd, sizeof(cmd));
1335 	cmd.opcode = MODE_SELECT;
1336 	cmd.length = scsi_select_len;
1337 
1338 	bzero(&scsi_select, scsi_select_len);
1339 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1340 	scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1341 	scsi_select.blk_desc.density = st->density;
1342 	if (st->flags & ST_FIXEDBLOCKS)
1343 		lto3b(st->blksize, scsi_select.blk_desc.blklen);
1344 	if (st->page_0_size)
1345 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1346 
1347 	/*
1348 	 * do the command
1349 	 */
1350 	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1351 	    sizeof(cmd), (u_char *) &scsi_select, scsi_select_len,
1352 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1353 }
1354 
1355 /*
1356  * skip N blocks/filemarks/seq filemarks/eom
1357  */
1358 int
1359 st_space(st, number, what, flags)
1360 	struct st_softc *st;
1361 	u_int what;
1362 	int flags;
1363 	int number;
1364 {
1365 	struct scsi_space cmd;
1366 	int error;
1367 
1368 	switch (what) {
1369 	case SP_BLKS:
1370 		if (st->flags & ST_PER_ACTION) {
1371 			if (number > 0) {
1372 				st->flags &= ~ST_PER_ACTION;
1373 				return EIO;
1374 			} else if (number < 0) {
1375 				if (st->flags & ST_AT_FILEMARK) {
1376 					/*
1377 					 * Handling of ST_AT_FILEMARK
1378 					 * in st_space will fill in the
1379 					 * right file mark count.
1380 					 */
1381 					error = st_space(st, 0, SP_FILEMARKS,
1382 						flags);
1383 					if (error)
1384 						return error;
1385 				}
1386 				if (st->flags & ST_BLANK_READ) {
1387 					st->flags &= ~ST_BLANK_READ;
1388 					return EIO;
1389 				}
1390 				st->flags &= ~ST_EIO_PENDING;
1391 			}
1392 		}
1393 		break;
1394 	case SP_FILEMARKS:
1395 		if (st->flags & ST_EIO_PENDING) {
1396 			if (number > 0) {
1397 				/* pretend we just discovered the error */
1398 				st->flags &= ~ST_EIO_PENDING;
1399 				return EIO;
1400 			} else if (number < 0) {
1401 				/* back away from the error */
1402 				st->flags &= ~ST_EIO_PENDING;
1403 			}
1404 		}
1405 		if (st->flags & ST_AT_FILEMARK) {
1406 			st->flags &= ~ST_AT_FILEMARK;
1407 			number--;
1408 		}
1409 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1410 			/* back away from unwritten tape */
1411 			st->flags &= ~ST_BLANK_READ;
1412 			number++;	/* XXX dubious */
1413 		}
1414 		break;
1415 	case SP_EOM:
1416 		if (st->flags & ST_EIO_PENDING) {
1417 			/* pretend we just discovered the error */
1418 			st->flags &= ~ST_EIO_PENDING;
1419 			return EIO;
1420 		}
1421 		if (st->flags & ST_AT_FILEMARK)
1422 			st->flags &= ~ST_AT_FILEMARK;
1423 		break;
1424 	}
1425 	if (number == 0)
1426 		return 0;
1427 
1428 	bzero(&cmd, sizeof(cmd));
1429 	cmd.opcode = SPACE;
1430 	cmd.byte2 = what;
1431 	lto3b(number, cmd.number);
1432 
1433 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1434 	    sizeof(cmd), 0, 0, 0, 900000, NULL, flags);
1435 }
1436 
1437 /*
1438  * write N filemarks
1439  */
1440 int
1441 st_write_filemarks(st, number, flags)
1442 	struct st_softc *st;
1443 	int flags;
1444 	int number;
1445 {
1446 	struct scsi_write_filemarks cmd;
1447 
1448 	/*
1449 	 * It's hard to write a negative number of file marks.
1450 	 * Don't try.
1451 	 */
1452 	if (number < 0)
1453 		return EINVAL;
1454 	switch (number) {
1455 	case 0:		/* really a command to sync the drive's buffers */
1456 		break;
1457 	case 1:
1458 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1459 			st->flags &= ~ST_WRITTEN;
1460 		else
1461 			st->flags |= ST_FM_WRITTEN;
1462 		st->flags &= ~ST_PER_ACTION;
1463 		break;
1464 	default:
1465 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1466 	}
1467 
1468 	bzero(&cmd, sizeof(cmd));
1469 	cmd.opcode = WRITE_FILEMARKS;
1470 	lto3b(number, cmd.number);
1471 
1472 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1473 	    sizeof(cmd), 0, 0, 0, 100000, NULL, flags);
1474 }
1475 
1476 /*
1477  * Make sure the right number of file marks is on tape if the
1478  * tape has been written.  If the position argument is true,
1479  * leave the tape positioned where it was originally.
1480  *
1481  * nmarks returns the number of marks to skip (or, if position
1482  * true, which were skipped) to get back original position.
1483  */
1484 int
1485 st_check_eod(st, position, nmarks, flags)
1486 	struct st_softc *st;
1487 	boolean position;
1488 	int *nmarks;
1489 	int flags;
1490 {
1491 	int error;
1492 
1493 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1494 	default:
1495 		*nmarks = 0;
1496 		return 0;
1497 	case ST_WRITTEN:
1498 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1499 		*nmarks = 1;
1500 		break;
1501 	case ST_WRITTEN | ST_2FM_AT_EOD:
1502 		*nmarks = 2;
1503 	}
1504 	error = st_write_filemarks(st, *nmarks, flags);
1505 	if (position && !error)
1506 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1507 	return error;
1508 }
1509 
1510 /*
1511  * load/unload/retension
1512  */
1513 int
1514 st_load(st, type, flags)
1515 	struct st_softc *st;
1516 	u_int type;
1517 	int flags;
1518 {
1519 	struct scsi_load cmd;
1520 
1521 	if (type != LD_LOAD) {
1522 		int error;
1523 		int nmarks;
1524 
1525 		error = st_check_eod(st, FALSE, &nmarks, flags);
1526 		if (error)
1527 			return error;
1528 	}
1529 	if (st->quirks & ST_Q_IGNORE_LOADS)
1530 		return 0;
1531 
1532 	bzero(&cmd, sizeof(cmd));
1533 	cmd.opcode = LOAD;
1534 	cmd.how = type;
1535 
1536 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1537 	    sizeof(cmd), 0, 0, ST_RETRIES, 300000, NULL, flags);
1538 }
1539 
1540 /*
1541  *  Rewind the device
1542  */
1543 int
1544 st_rewind(st, immediate, flags)
1545 	struct st_softc *st;
1546 	u_int immediate;
1547 	int flags;
1548 {
1549 	struct scsi_rewind cmd;
1550 	int error;
1551 	int nmarks;
1552 
1553 	error = st_check_eod(st, FALSE, &nmarks, flags);
1554 	if (error)
1555 		return error;
1556 	st->flags &= ~ST_PER_ACTION;
1557 
1558 	bzero(&cmd, sizeof(cmd));
1559 	cmd.opcode = REWIND;
1560 	cmd.byte2 = immediate;
1561 
1562 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1563 	    sizeof(cmd), 0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL,
1564 	    flags);
1565 }
1566 
1567 /*
1568  * Look at the returned sense and act on the error and detirmine
1569  * The unix error number to pass back... (0 = report no error)
1570  *                            (-1 = continue processing)
1571  */
1572 int
1573 st_interpret_sense(xs)
1574 	struct scsi_xfer *xs;
1575 {
1576 	struct scsi_link *sc_link = xs->sc_link;
1577 	struct scsi_sense_data *sense = &xs->sense;
1578 	struct buf *bp = xs->bp;
1579 	struct st_softc *st = sc_link->device_softc;
1580 	u_int8_t key;
1581 	u_int32_t info;
1582 
1583 	/*
1584 	 * Get the sense fields and work out what code
1585 	 */
1586 	if (sense->error_code & SSD_ERRCODE_VALID) {
1587 		bcopy(sense->extended_info, &info, sizeof info);
1588 		info = ntohl(info);
1589 	} else
1590 		info = xs->datalen;	/* bad choice if fixed blocks */
1591 	if ((sense->error_code & SSD_ERRCODE) != 0x70)
1592 		return -1;	/* let the generic code handle it */
1593 	if (st->flags & ST_FIXEDBLOCKS) {
1594 		xs->resid = info * st->blksize;
1595 		if (sense->extended_flags & SSD_EOM) {
1596 			st->flags |= ST_EIO_PENDING;
1597 			if (bp)
1598 				bp->b_resid = xs->resid;
1599 		}
1600 		if (sense->extended_flags & SSD_FILEMARK) {
1601 			st->flags |= ST_AT_FILEMARK;
1602 			if (bp)
1603 				bp->b_resid = xs->resid;
1604 		}
1605 		if (sense->extended_flags & SSD_ILI) {
1606 			st->flags |= ST_EIO_PENDING;
1607 			if (bp)
1608 				bp->b_resid = xs->resid;
1609 			if (sense->error_code & SSD_ERRCODE_VALID &&
1610 			    (xs->flags & SCSI_SILENT) == 0)
1611 				printf("%s: block wrong size, %d blocks residual\n",
1612 				    st->sc_dev.dv_xname, info);
1613 
1614 			/*
1615 			 * This quirk code helps the drive read
1616 			 * the first tape block, regardless of
1617 			 * format.  That is required for these
1618 			 * drives to return proper MODE SENSE
1619 			 * information.
1620 			 */
1621 			if ((st->quirks & ST_Q_SENSE_HELP) &&
1622 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
1623 				st->blksize -= 512;
1624 		}
1625 		/*
1626 		 * If no data was tranfered, do it immediatly
1627 		 */
1628 		if (xs->resid >= xs->datalen) {
1629 			if (st->flags & ST_EIO_PENDING)
1630 				return EIO;
1631 			if (st->flags & ST_AT_FILEMARK) {
1632 				if (bp)
1633 					bp->b_resid = xs->resid;
1634 				return 0;
1635 			}
1636 		}
1637 	} else {		/* must be variable mode */
1638 		xs->resid = xs->datalen;	/* to be sure */
1639 		if (sense->extended_flags & SSD_EOM)
1640 			return EIO;
1641 		if (sense->extended_flags & SSD_FILEMARK) {
1642 			if (bp)
1643 				bp->b_resid = bp->b_bcount;
1644 			return 0;
1645 		}
1646 		if (sense->extended_flags & SSD_ILI) {
1647 			if (info < 0) {
1648 				/*
1649 				 * the record was bigger than the read
1650 				 */
1651 				if ((xs->flags & SCSI_SILENT) == 0)
1652 					printf("%s: %d-byte record too big\n",
1653 					    st->sc_dev.dv_xname,
1654 					    xs->datalen - info);
1655 				return EIO;
1656 			}
1657 			xs->resid = info;
1658 			if (bp)
1659 				bp->b_resid = info;
1660 		}
1661 	}
1662 	key = sense->extended_flags & SSD_KEY;
1663 
1664 	if (key == 0x8) {
1665 		/*
1666 		 * This quirk code helps the drive read the
1667 		 * first tape block, regardless of format.  That
1668 		 * is required for these drives to return proper
1669 		 * MODE SENSE information.
1670 		 */
1671 		if ((st->quirks & ST_Q_SENSE_HELP) &&
1672 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
1673 			/* still starting */
1674 			st->blksize -= 512;
1675 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
1676 			st->flags |= ST_BLANK_READ;
1677 			xs->resid = xs->datalen;
1678 			if (bp) {
1679 				bp->b_resid = xs->resid;
1680 				/* return an EOF */
1681 			}
1682 			return 0;
1683 		}
1684 	}
1685 	return -1;		/* let the default/generic handler handle it */
1686 }
1687 
1688 /*
1689  * The quirk here is that the drive returns some value to st_mode_sense
1690  * incorrectly until the tape has actually passed by the head.
1691  *
1692  * The method is to set the drive to large fixed-block state (user-specified
1693  * density and 1024-byte blocks), then read and rewind to get it to sense the
1694  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
1695  * work, as a last resort, try variable- length blocks.  The result will be
1696  * the ability to do an accurate st_mode_sense.
1697  *
1698  * We know we can do a rewind because we just did a load, which implies rewind.
1699  * Rewind seems preferable to space backward if we have a virgin tape.
1700  *
1701  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
1702  * error processing, both part of st_interpret_sense.
1703  */
1704 int
1705 st_touch_tape(st)
1706 	struct st_softc *st;
1707 {
1708 	char *buf;
1709 	int readsize;
1710 	int error;
1711 
1712 	buf = malloc(1024, M_TEMP, M_NOWAIT);
1713 	if (!buf)
1714 		return ENOMEM;
1715 
1716 	if (error = st_mode_sense(st, 0))
1717 		goto bad;
1718 	st->blksize = 1024;
1719 	do {
1720 		switch (st->blksize) {
1721 		case 512:
1722 		case 1024:
1723 			readsize = st->blksize;
1724 			st->flags |= ST_FIXEDBLOCKS;
1725 			break;
1726 		default:
1727 			readsize = 1;
1728 			st->flags &= ~ST_FIXEDBLOCKS;
1729 		}
1730 		if (error = st_mode_select(st, 0))
1731 			goto bad;
1732 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
1733 		if (error = st_rewind(st, 0, 0)) {
1734 bad:			free(buf, M_TEMP);
1735 			return error;
1736 		}
1737 	} while (readsize != 1 && readsize > st->blksize);
1738 
1739 	free(buf, M_TEMP);
1740 	return 0;
1741 }
1742 
1743 int
1744 stdump()
1745 {
1746 
1747 	/* Not implemented. */
1748 	return EINVAL;
1749 }
1750