xref: /openbsd/sys/scsi/st.c (revision 07ea8d15)
1 /*	$OpenBSD: st.c,v 1.13 1996/12/11 19:08:20 deraadt Exp $	*/
2 /*	$NetBSD: st.c,v 1.66 1996/05/05 19:53:01 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1994 Charles Hannum.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by Charles Hannum.
18  * 4. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Originally written by Julian Elischer (julian@tfs.com)
35  * for TRW Financial Systems for use under the MACH(2.5) operating system.
36  *
37  * TRW Financial Systems, in accordance with their agreement with Carnegie
38  * Mellon University, makes this software available to CMU to distribute
39  * or use in any manner that they see fit as long as this message is kept with
40  * the software. For this reason TFS also grants any other persons or
41  * organisations permission to use or modify this software.
42  *
43  * TFS supplies this software to be publicly redistributed
44  * on the understanding that TFS is not responsible for the correct
45  * functioning of this software in any circumstances.
46  *
47  * Ported to run under 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
48  * major changes by Julian Elischer (julian@jules.dialix.oz.au) May 1993
49  */
50 
51 /*
52  * To do:
53  * work out some better way of guessing what a good timeout is going
54  * to be depending on whether we expect to retension or not.
55  */
56 
57 #include <sys/types.h>
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/fcntl.h>
61 #include <sys/errno.h>
62 #include <sys/ioctl.h>
63 #include <sys/malloc.h>
64 #include <sys/buf.h>
65 #include <sys/proc.h>
66 #include <sys/user.h>
67 #include <sys/mtio.h>
68 #include <sys/device.h>
69 #include <sys/conf.h>
70 
71 #include <scsi/scsi_all.h>
72 #include <scsi/scsi_tape.h>
73 #include <scsi/scsiconf.h>
74 
75 /* Defines for device specific stuff */
76 #define DEF_FIXED_BSIZE  512
77 #define	ST_RETRIES	4	/* only on non IO commands */
78 
79 #define STMODE(z)	( minor(z)       & 0x03)
80 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
81 #define STUNIT(z)	((minor(z) >> 4)       )
82 #define CTLMODE	3
83 
84 #define SCSI_2_MAX_DENSITY_CODE	0x17	/* maximum density code specified
85 					 * in SCSI II spec. */
86 /*
87  * Define various devices that we know mis-behave in some way,
88  * and note how they are bad, so we can correct for them
89  */
90 struct modes {
91 	u_int quirks;			/* same definitions as in quirkdata */
92 	int blksize;
93 	u_int8_t density;
94 };
95 
96 struct quirkdata {
97 	u_int quirks;
98 #define	ST_Q_FORCE_BLKSIZE	0x0001
99 #define	ST_Q_SENSE_HELP		0x0002	/* must do READ for good MODE SENSE */
100 #define	ST_Q_IGNORE_LOADS	0x0004
101 #define	ST_Q_BLKSIZE		0x0008	/* variable-block media_blksize > 0 */
102 	u_int page_0_size;
103 #define	MAX_PAGE_0_SIZE	64
104 	struct modes modes[4];
105 };
106 
107 struct st_quirk_inquiry_pattern {
108 	struct scsi_inquiry_pattern pattern;
109 	struct quirkdata quirkdata;
110 };
111 
112 struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
113 	{{T_SEQUENTIAL, T_REMOV,
114 	 "        ", "                ", "    "}, {0, 0, {
115 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
116 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
117 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
118 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
119 	}}},
120 	{{T_SEQUENTIAL, T_REMOV,
121 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
122 		{0, 0, 0},				/* minor 0-3 */
123 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
124 		{0, 0, QIC_150},			/* minor 8-11 */
125 		{0, 0, QIC_120}				/* minor 12-15 */
126 	}}},
127  	{{T_SEQUENTIAL, T_REMOV,
128  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
129 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
130 		{0, 0, QIC_525},			/* minor 4-7 */
131 		{0, 0, QIC_150},			/* minor 8-11 */
132 		{0, 0, QIC_120}				/* minor 12-15 */
133 	}}},
134 	/*
135 	 * At least -005 and -007 need this.  I'll assume they all do unless I
136 	 * hear otherwise.  - mycroft, 31MAR1994
137 	 */
138 	{{T_SEQUENTIAL, T_REMOV,
139 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
140 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
141 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
142 		{0, 0, QIC_150},			/* minor 8-11 */
143 		{0, 0, QIC_120}				/* minor 12-15 */
144 	}}},
145 	/*
146 	 * One user reports that this works for his tape drive.  It probably
147 	 * needs more work.  - mycroft, 09APR1994
148 	 */
149 	{{T_SEQUENTIAL, T_REMOV,
150 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
151 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
152 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
153 		{0, 0, QIC_150},			/* minor 8-11 */
154 		{0, 0, QIC_120}				/* minor 12-15 */
155 	}}},
156 	{{T_SEQUENTIAL, T_REMOV,
157 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
158 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
159 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
160 		{0, 0, QIC_150},			/* minor 8-11 */
161 		{0, 0, QIC_120}				/* minor 12-15 */
162 	}}},
163 	{{T_SEQUENTIAL, T_REMOV,
164 	 "ARCHIVE ", "VIPER 150  21247", ""},     {0, 12, {
165 		{0, 0, 0},				/* minor 0-3 */
166 		{0, 0, QIC_150},			/* minor 4-7 */
167 		{0, 0, QIC_120},			/* minor 8-11 */
168 		{0, 0, QIC_24}				/* minor 12-15 */
169 	}}},
170 	{{T_SEQUENTIAL, T_REMOV,
171 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
172 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
173 		{0, 0, QIC_11},				/* minor 4-7 */
174 		{0, 0, QIC_24},				/* minor 8-11 */
175 		{0, 0, QIC_24}				/* minor 12-15 */
176 	}}},
177 	{{T_SEQUENTIAL, T_REMOV,
178 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
179 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
180 		{0, 0, QIC_24},				/* minor 4-7 */
181 		{0, 0, QIC_120},			/* minor 8-11 */
182 		{0, 0, QIC_150}				/* minor 12-15 */
183 	}}},
184 	{{T_SEQUENTIAL, T_REMOV,
185 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
186 		{0, 0, 0},				/* minor 0-3 */
187 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
188 		{0, 0, QIC_150},			/* minor 8-11 */
189 		{0, 0, QIC_120}				/* minor 12-15 */
190 	}}},
191 	{{T_SEQUENTIAL, T_REMOV,
192 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
193 		{0, 0, 0},				/* minor 0-3 */
194 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
195 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
196 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
197 	}}},
198 	{{T_SEQUENTIAL, T_REMOV,
199 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
200 		{0, 0, 0},				/* minor 0-3 */
201 		{0, 0, 0},				/* minor 4-7 */
202 		{0, 0, 0},				/* minor 8-11 */
203 		{0, 0, 0}				/* minor 12-15 */
204 	}}},
205 #if 0
206 	{{T_SEQUENTIAL, T_REMOV,
207 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
208 		{0, 0, 0},				/* minor 0-3 */
209 		{0, 0, 0},				/* minor 4-7 */
210 		{0, 0, 0},				/* minor 8-11 */
211 		{0, 0, 0}				/* minor 12-15 */
212 	}}},
213 #endif
214 	{{T_SEQUENTIAL, T_REMOV,
215 	 "WANGTEK ", "5150ES SCSI FA15\0""01 A", "????"}, {0, 0, {
216 		{0, ST_Q_IGNORE_LOADS, 0},		/* minor 0-3 */
217 		{0, 0, 0},				/* minor 4-7 */
218 		{0, 0, 0},				/* minor 8-11 */
219 		{0, 0, 0}				/* minor 12-15 */
220 	}}},
221 };
222 
223 #define NOEJECT 0
224 #define EJECT 1
225 
226 struct st_softc {
227 	struct device sc_dev;
228 /*--------------------present operating parameters, flags etc.----------------*/
229 	int flags;		/* see below                          */
230 	u_int quirks;		/* quirks for the open mode           */
231 	int blksize;		/* blksize we are using                */
232 	u_int8_t density;	/* present density                    */
233 	u_int page_0_size;	/* size of page 0 data		      */
234 	u_int last_dsty;	/* last density opened               */
235 /*--------------------device/scsi parameters----------------------------------*/
236 	struct scsi_link *sc_link;	/* our link to the adpter etc.        */
237 /*--------------------parameters reported by the device ----------------------*/
238 	int blkmin;		/* min blk size                       */
239 	int blkmax;		/* max blk size                       */
240 	struct quirkdata *quirkdata;	/* if we have a rogue entry           */
241 /*--------------------parameters reported by the device for this media--------*/
242 	u_long numblks;		/* nominal blocks capacity            */
243 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
244 	u_int8_t media_density;	/* this is what it said when asked    */
245 /*--------------------quirks for the whole drive------------------------------*/
246 	u_int drive_quirks;	/* quirks of this drive               */
247 /*--------------------How we should set up when opening each minor device----*/
248 	struct modes modes[4];	/* plus more for each mode            */
249 	u_int8_t  modeflags[4];	/* flags for the modes                */
250 #define DENSITY_SET_BY_USER	0x01
251 #define DENSITY_SET_BY_QUIRK	0x02
252 #define BLKSIZE_SET_BY_USER	0x04
253 #define BLKSIZE_SET_BY_QUIRK	0x08
254 /*--------------------storage for sense data returned by the drive------------*/
255 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
256 						 * additional sense data needed
257 						 * for mode sense/select.
258 						 */
259 	struct buf buf_queue;		/* the queue of pending IO operations */
260 };
261 
262 
263 int	stmatch __P((struct device *, void *, void *));
264 void	stattach __P((struct device *, struct device *, void *));
265 void	st_identify_drive __P((struct st_softc *, struct scsi_inquiry_data *));
266 void	st_loadquirks __P((struct st_softc *));
267 int	st_mount_tape __P((dev_t, int));
268 void	st_unmount __P((struct st_softc *, boolean));
269 int	st_decide_mode __P((struct st_softc *, boolean));
270 void	ststart __P((void *));
271 int	st_read __P((struct st_softc *, char *, int, int));
272 int	st_read_block_limits __P((struct st_softc *, int));
273 int	st_mode_sense __P((struct st_softc *, int));
274 int	st_mode_select __P((struct st_softc *, int));
275 int	st_space __P((struct st_softc *, int, u_int, int));
276 int	st_write_filemarks __P((struct st_softc *, int, int));
277 int	st_check_eod __P((struct st_softc *, boolean, int *, int));
278 int	st_load __P((struct st_softc *, u_int, int));
279 int	st_rewind __P((struct st_softc *, u_int, int));
280 int	st_interpret_sense __P((struct scsi_xfer *));
281 int	st_touch_tape __P((struct st_softc *));
282 int	st_erase __P((struct st_softc *, int full, int flags));
283 
284 struct cfattach st_ca = {
285 	sizeof(struct st_softc), stmatch, stattach
286 };
287 
288 struct cfdriver st_cd = {
289 	NULL, "st", DV_TAPE
290 };
291 
292 struct scsi_device st_switch = {
293 	st_interpret_sense,
294 	ststart,
295 	NULL,
296 	NULL,
297 };
298 
299 #define	ST_INFO_VALID	0x0001
300 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
301 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
302 #define	ST_FIXEDBLOCKS	0x0008
303 #define	ST_AT_FILEMARK	0x0010
304 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
305 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode              */
306 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
307 #define	ST_FM_WRITTEN	0x0100	/*
308 				 * EOF file mark written  -- used with
309 				 * ~ST_WRITTEN to indicate that multiple file
310 				 * marks have been written
311 				 */
312 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
313 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
314 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
315 #define	ST_DONTBUFFER	0x1000	/* Disable buffering/caching */
316 
317 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
318 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN | \
319 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN | \
320 			 ST_2FM_AT_EOD | ST_PER_ACTION)
321 
322 struct scsi_inquiry_pattern st_patterns[] = {
323 	{T_SEQUENTIAL, T_REMOV,
324 	 "",         "",                 ""},
325 };
326 
327 int
328 stmatch(parent, match, aux)
329 	struct device *parent;
330 	void *match, *aux;
331 {
332 	struct scsibus_attach_args *sa = aux;
333 	int priority;
334 
335 	(void)scsi_inqmatch(sa->sa_inqbuf,
336 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
337 	    sizeof(st_patterns[0]), &priority);
338 	return (priority);
339 }
340 
341 /*
342  * The routine called by the low level scsi routine when it discovers
343  * A device suitable for this driver
344  */
345 void
346 stattach(parent, self, aux)
347 	struct device *parent, *self;
348 	void *aux;
349 {
350 	struct st_softc *st = (void *)self;
351 	struct scsibus_attach_args *sa = aux;
352 	struct scsi_link *sc_link = sa->sa_sc_link;
353 
354 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
355 
356 	/*
357 	 * Store information needed to contact our base driver
358 	 */
359 	st->sc_link = sc_link;
360 	sc_link->device = &st_switch;
361 	sc_link->device_softc = st;
362 	sc_link->openings = 1;
363 
364 	/*
365 	 * Check if the drive is a known criminal and take
366 	 * Any steps needed to bring it into line
367 	 */
368 	st_identify_drive(st, sa->sa_inqbuf);
369 
370 	/*
371 	 * Use the subdriver to request information regarding
372 	 * the drive. We cannot use interrupts yet, so the
373 	 * request must specify this.
374 	 */
375 	printf("\n");
376 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
377 	if (scsi_test_unit_ready(sc_link,
378 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
379 	    st_mode_sense(st,
380 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
381 		printf("drive empty\n");
382 	else {
383 		printf("density code 0x%x, ", st->media_density);
384 		if (st->media_blksize > 0)
385 			printf("%d-byte", st->media_blksize);
386 		else
387 			printf("variable");
388 		printf(" blocks, write-%s\n",
389 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
390 	}
391 
392 	/*
393 	 * Set up the buf queue for this device
394 	 */
395 	st->buf_queue.b_active = 0;
396 	st->buf_queue.b_actf = 0;
397 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
398 }
399 
400 /*
401  * Use the inquiry routine in 'scsi_base' to get drive info so we can
402  * Further tailor our behaviour.
403  */
404 void
405 st_identify_drive(st, inqbuf)
406 	struct st_softc *st;
407 	struct scsi_inquiry_data *inqbuf;
408 {
409 	struct st_quirk_inquiry_pattern *finger;
410 	int priority;
411 
412 	finger = (struct st_quirk_inquiry_pattern *)scsi_inqmatch(inqbuf,
413 	    (caddr_t)st_quirk_patterns,
414 	    sizeof(st_quirk_patterns)/sizeof(st_quirk_patterns[0]),
415 	    sizeof(st_quirk_patterns[0]), &priority);
416 	if (priority != 0) {
417 		st->quirkdata = &finger->quirkdata;
418 		st->drive_quirks = finger->quirkdata.quirks;
419 		st->quirks = finger->quirkdata.quirks;	/* start value */
420 		st->page_0_size = finger->quirkdata.page_0_size;
421 		st_loadquirks(st);
422 	}
423 }
424 
425 /*
426  * initialise the subdevices to the default (QUIRK) state.
427  * this will remove any setting made by the system operator or previous
428  * operations.
429  */
430 void
431 st_loadquirks(st)
432 	struct st_softc *st;
433 {
434 	int i;
435 	struct	modes *mode;
436 	struct	modes *mode2;
437 
438 	mode = st->quirkdata->modes;
439 	mode2 = st->modes;
440 	for (i = 0; i < 4; i++) {
441 		bzero(mode2, sizeof(struct modes));
442 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
443 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
444 		    DENSITY_SET_BY_USER);
445 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
446 			mode2->blksize = mode->blksize;
447 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
448 		}
449 		if (mode->density) {
450 			mode2->density = mode->density;
451 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
452 		}
453 		mode++;
454 		mode2++;
455 	}
456 }
457 
458 /*
459  * open the device.
460  */
461 int
462 stopen(dev, flags, mode, p)
463 	dev_t dev;
464 	int flags;
465 	int mode;
466 	struct proc *p;
467 {
468 	int unit;
469 	u_int stmode, dsty;
470 	int error = 0;
471 	struct st_softc *st;
472 	struct scsi_link *sc_link;
473 
474 	unit = STUNIT(dev);
475 	if (unit >= st_cd.cd_ndevs)
476 		return ENXIO;
477 	st = st_cd.cd_devs[unit];
478 	if (!st)
479 		return ENXIO;
480 
481 	stmode = STMODE(dev);
482 	dsty = STDSTY(dev);
483 	sc_link = st->sc_link;
484 
485 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
486 	    unit, st_cd.cd_ndevs));
487 
488 	/*
489 	 * Only allow one at a time
490 	 */
491 	if (sc_link->flags & SDEV_OPEN) {
492 		printf("%s: already open\n", st->sc_dev.dv_xname);
493 		return EBUSY;
494 	}
495 
496 	/*
497 	 * Catch any unit attention errors.
498 	 */
499 	error = scsi_test_unit_ready(sc_link,
500 				     SCSI_IGNORE_MEDIA_CHANGE |
501 				     (stmode == CTLMODE ?
502 					SCSI_IGNORE_NOT_READY : 0));
503 	if (error)
504 		goto bad;
505 
506 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
507 
508 	/*
509 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
510 	 * then the device has been opened to set defaults
511 	 * This mode does NOT ALLOW I/O, only ioctls
512 	 */
513 	if (stmode == CTLMODE)
514 		return 0;
515 
516 	/*
517 	 * if it's a different mode, or if the media has been
518 	 * invalidated, unmount the tape from the previous
519 	 * session but continue with open processing
520 	 */
521 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
522 		st_unmount(st, NOEJECT);
523 
524 	/*
525 	 * If we are not mounted, then we should start a new
526 	 * mount session.
527 	 */
528 	if (!(st->flags & ST_MOUNTED)) {
529 		st_mount_tape(dev, flags);
530 		st->last_dsty = dsty;
531 	}
532 
533 	/*
534 	 * Make sure that a tape opened in write-only mode will have
535 	 * file marks written on it when closed, even if not written to.
536 	 * This is for SUN compatibility
537 	 */
538 	if ((flags & O_ACCMODE) == FWRITE)
539 		st->flags |= ST_WRITTEN;
540 
541 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
542 	return 0;
543 
544 bad:
545 	st_unmount(st, NOEJECT);
546 	sc_link->flags &= ~SDEV_OPEN;
547 	return error;
548 }
549 
550 /*
551  * close the device.. only called if we are the LAST
552  * occurence of an open device
553  */
554 int
555 stclose(dev, flags, mode, p)
556 	dev_t dev;
557 	int flags;
558 	int mode;
559 	struct proc *p;
560 {
561 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
562 
563 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
564 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
565 		st_write_filemarks(st, 1, 0);
566 	switch (STMODE(dev)) {
567 	case 0:
568 	case 3:		/* for now */
569 		st_unmount(st, NOEJECT);
570 		break;
571 	case 1:
572 		/* leave mounted unless media seems to have been removed */
573 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
574 			st_unmount(st, NOEJECT);
575 		break;
576 	case 2:
577 		st_unmount(st, EJECT);
578 		break;
579 	}
580 	st->sc_link->flags &= ~SDEV_OPEN;
581 
582 	return 0;
583 }
584 
585 /*
586  * Start a new mount session.
587  * Copy in all the default parameters from the selected device mode.
588  * and try guess any that seem to be defaulted.
589  */
590 int
591 st_mount_tape(dev, flags)
592 	dev_t dev;
593 	int flags;
594 {
595 	int unit;
596 	u_int mode, dsty;
597 	struct st_softc *st;
598 	struct scsi_link *sc_link;
599 	int error = 0;
600 
601 	unit = STUNIT(dev);
602 	mode = STMODE(dev);
603 	dsty = STDSTY(dev);
604 	st = st_cd.cd_devs[unit];
605 	sc_link = st->sc_link;
606 
607 	if (st->flags & ST_MOUNTED)
608 		return 0;
609 
610 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
611 	st->flags |= ST_NEW_MOUNT;
612 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
613 	/*
614 	 * If the media is new, then make sure we give it a chance to
615 	 * to do a 'load' instruction.  (We assume it is new.)
616 	 */
617 	if ((error = st_load(st, LD_LOAD, 0)) != 0)
618 		return error;
619 	/*
620 	 * Throw another dummy instruction to catch
621 	 * 'Unit attention' errors. Some drives appear to give
622 	 * these after doing a Load instruction.
623 	 * (noteably some DAT drives)
624 	 */
625 	scsi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
626 
627 	/*
628 	 * Some devices can't tell you much until they have been
629 	 * asked to look at the media. This quirk does this.
630 	 */
631 	if (st->quirks & ST_Q_SENSE_HELP)
632 		if ((error = st_touch_tape(st)) != 0)
633 			return error;
634 	/*
635 	 * Load the physical device parameters
636 	 * loads: blkmin, blkmax
637 	 */
638 	if ((error = st_read_block_limits(st, 0)) != 0)
639 		return error;
640 	/*
641 	 * Load the media dependent parameters
642 	 * includes: media_blksize,media_density,numblks
643 	 * As we have a tape in, it should be reflected here.
644 	 * If not you may need the "quirk" above.
645 	 */
646 	if ((error = st_mode_sense(st, 0)) != 0)
647 		return error;
648 	/*
649 	 * If we have gained a permanent density from somewhere,
650 	 * then use it in preference to the one supplied by
651 	 * default by the driver.
652 	 */
653 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
654 		st->density = st->modes[dsty].density;
655 	else
656 		st->density = st->media_density;
657 	/*
658 	 * If we have gained a permanent blocksize
659 	 * then use it in preference to the one supplied by
660 	 * default by the driver.
661 	 */
662 	st->flags &= ~ST_FIXEDBLOCKS;
663 	if (st->modeflags[dsty] & (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
664 		st->blksize = st->modes[dsty].blksize;
665 		if (st->blksize)
666 			st->flags |= ST_FIXEDBLOCKS;
667 	} else {
668 		if ((error = st_decide_mode(st, FALSE)) != 0)
669 			return error;
670 	}
671 	if ((error = st_mode_select(st, 0)) != 0) {
672 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
673 		return error;
674 	}
675 	scsi_prevent(sc_link, PR_PREVENT,
676 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
677 	st->flags &= ~ST_NEW_MOUNT;
678 	st->flags |= ST_MOUNTED;
679 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
680 
681 	return 0;
682 }
683 
684 /*
685  * End the present mount session.
686  * Rewind, and optionally eject the tape.
687  * Reset various flags to indicate that all new
688  * operations require another mount operation
689  */
690 void
691 st_unmount(st, eject)
692 	struct st_softc *st;
693 	boolean eject;
694 {
695 	struct scsi_link *sc_link = st->sc_link;
696 	int nmarks;
697 
698 	if (!(st->flags & ST_MOUNTED))
699 		return;
700 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
701 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
702 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
703 	scsi_prevent(sc_link, PR_ALLOW,
704 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
705 	if (eject)
706 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
707 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
708 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
709 }
710 
711 /*
712  * Given all we know about the device, media, mode, 'quirks' and
713  * initial operation, make a decision as to how we should be set
714  * to run (regarding blocking and EOD marks)
715  */
716 int
717 st_decide_mode(st, first_read)
718 	struct st_softc *st;
719 	boolean	first_read;
720 {
721 #ifdef SCSIDEBUG
722 	struct scsi_link *sc_link = st->sc_link;
723 #endif
724 
725 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
726 
727 	/*
728 	 * If the drive can only handle fixed-length blocks and only at
729 	 * one size, perhaps we should just do that.
730 	 */
731 	if (st->blkmin && (st->blkmin == st->blkmax)) {
732 		st->flags |= ST_FIXEDBLOCKS;
733 		st->blksize = st->blkmin;
734 		SC_DEBUG(sc_link, SDEV_DB3,
735 		    ("blkmin == blkmax of %d\n", st->blkmin));
736 		goto done;
737 	}
738 	/*
739 	 * If the tape density mandates (or even suggests) use of fixed
740 	 * or variable-length blocks, comply.
741 	 */
742 	switch (st->density) {
743 	case HALFINCH_800:
744 	case HALFINCH_1600:
745 	case HALFINCH_6250:
746 	case DDS:
747 		st->flags &= ~ST_FIXEDBLOCKS;
748 		st->blksize = 0;
749 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
750 		goto done;
751 	case QIC_11:
752 	case QIC_24:
753 	case QIC_120:
754 	case QIC_150:
755 	case QIC_525:
756 	case QIC_1320:
757 		st->flags |= ST_FIXEDBLOCKS;
758 		if (st->media_blksize > 0)
759 			st->blksize = st->media_blksize;
760 		else
761 			st->blksize = DEF_FIXED_BSIZE;
762 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
763 		goto done;
764 	}
765 	/*
766 	 * If we're about to read the tape, perhaps we should choose
767 	 * fixed or variable-length blocks and block size according to
768 	 * what the drive found on the tape.
769 	 */
770 	if (first_read &&
771 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
772 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
773 	    (st->media_blksize == 1024))) {
774 		if (st->media_blksize > 0)
775 			st->flags |= ST_FIXEDBLOCKS;
776 		else
777 			st->flags &= ~ST_FIXEDBLOCKS;
778 		st->blksize = st->media_blksize;
779 		SC_DEBUG(sc_link, SDEV_DB3,
780 		    ("Used media_blksize of %d\n", st->media_blksize));
781 		goto done;
782 	}
783 	/*
784 	 * We're getting no hints from any direction.  Choose variable-
785 	 * length blocks arbitrarily.
786 	 */
787 	st->flags &= ~ST_FIXEDBLOCKS;
788 	st->blksize = 0;
789 	SC_DEBUG(sc_link, SDEV_DB3,
790 	    ("Give up and default to variable mode\n"));
791 
792 done:
793 	/*
794 	 * Decide whether or not to write two file marks to signify end-
795 	 * of-data.  Make the decision as a function of density.  If
796 	 * the decision is not to use a second file mark, the SCSI BLANK
797 	 * CHECK condition code will be recognized as end-of-data when
798 	 * first read.
799 	 * (I think this should be a by-product of fixed/variable..julian)
800 	 */
801 	switch (st->density) {
802 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
803 	case QIC_11:
804 	case QIC_24:
805 	case QIC_120:
806 	case QIC_150:
807 	case QIC_525:
808 	case QIC_1320:
809 		st->flags &= ~ST_2FM_AT_EOD;
810 		break;
811 	default:
812 		st->flags |= ST_2FM_AT_EOD;
813 	}
814 	return 0;
815 }
816 
817 /*
818  * Actually translate the requested transfer into
819  * one the physical driver can understand
820  * The transfer is described by a buf and will include
821  * only one physical transfer.
822  */
823 void
824 ststrategy(bp)
825 	struct buf *bp;
826 {
827 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
828 	struct buf *dp;
829 	int s;
830 
831 	SC_DEBUG(st->sc_link, SDEV_DB1,
832 	    ("ststrategy %ld bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
833 	/*
834 	 * If it's a null transfer, return immediatly
835 	 */
836 	if (bp->b_bcount == 0)
837 		goto done;
838 	/*
839 	 * Odd sized request on fixed drives are verboten
840 	 */
841 	if (st->flags & ST_FIXEDBLOCKS) {
842 		if (bp->b_bcount % st->blksize) {
843 			printf("%s: bad request, must be multiple of %d\n",
844 			    st->sc_dev.dv_xname, st->blksize);
845 			bp->b_error = EIO;
846 			goto bad;
847 		}
848 	}
849 	/*
850 	 * as are out-of-range requests on variable drives.
851 	 */
852 	else if (bp->b_bcount < st->blkmin ||
853 		 (st->blkmax && bp->b_bcount > st->blkmax)) {
854 		printf("%s: bad request, must be between %d and %d\n",
855 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
856 		bp->b_error = EIO;
857 		goto bad;
858 	}
859 	s = splbio();
860 
861 	/*
862 	 * Place it in the queue of activities for this tape
863 	 * at the end (a bit silly because we only have on user..
864 	 * (but it could fork()))
865 	 */
866 	dp = &st->buf_queue;
867 	bp->b_actf = NULL;
868 	bp->b_actb = dp->b_actb;
869 	*dp->b_actb = bp;
870 	dp->b_actb = &bp->b_actf;
871 
872 	/*
873 	 * Tell the device to get going on the transfer if it's
874 	 * not doing anything, otherwise just wait for completion
875 	 * (All a bit silly if we're only allowing 1 open but..)
876 	 */
877 	ststart(st);
878 
879 	splx(s);
880 	return;
881 bad:
882 	bp->b_flags |= B_ERROR;
883 done:
884 	/*
885 	 * Correctly set the buf to indicate a completed xfer
886 	 */
887 	bp->b_resid = bp->b_bcount;
888 	biodone(bp);
889 	return;
890 }
891 
892 /*
893  * ststart looks to see if there is a buf waiting for the device
894  * and that the device is not already busy. If both are true,
895  * It dequeues the buf and creates a scsi command to perform the
896  * transfer required. The transfer request will call scsi_done
897  * on completion, which will in turn call this routine again
898  * so that the next queued transfer is performed.
899  * The bufs are queued by the strategy routine (ststrategy)
900  *
901  * This routine is also called after other non-queued requests
902  * have been made of the scsi driver, to ensure that the queue
903  * continues to be drained.
904  * ststart() is called at splbio
905  */
906 void
907 ststart(v)
908 	void *v;
909 {
910 	struct st_softc *st = v;
911 	struct scsi_link *sc_link = st->sc_link;
912 	register struct buf *bp, *dp;
913 	struct scsi_rw_tape cmd;
914 	int flags;
915 
916 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
917 	/*
918 	 * See if there is a buf to do and we are not already
919 	 * doing one
920 	 */
921 	while (sc_link->openings > 0) {
922 		/* if a special awaits, let it proceed first */
923 		if (sc_link->flags & SDEV_WAITING) {
924 			sc_link->flags &= ~SDEV_WAITING;
925 			wakeup((caddr_t)sc_link);
926 			return;
927 		}
928 
929 		dp = &st->buf_queue;
930 		if ((bp = dp->b_actf) == NULL)
931 			return;
932 		if ((dp = bp->b_actf) != NULL)
933 			dp->b_actb = bp->b_actb;
934 		else
935 			st->buf_queue.b_actb = bp->b_actb;
936 		*bp->b_actb = dp;
937 
938 		/*
939 		 * if the device has been unmounted by the user
940 		 * then throw away all requests until done
941 		 */
942 		if (!(st->flags & ST_MOUNTED) ||
943 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
944 			/* make sure that one implies the other.. */
945 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
946 			bp->b_flags |= B_ERROR;
947 			bp->b_resid = bp->b_bcount;
948 			bp->b_error = EIO;
949 			biodone(bp);
950 			continue;
951 		}
952 		/*
953 		 * only FIXEDBLOCK devices have pending operations
954 		 */
955 		if (st->flags & ST_FIXEDBLOCKS) {
956 			/*
957 			 * If we are at a filemark but have not reported it yet
958 			 * then we should report it now
959 			 */
960 			if (st->flags & ST_AT_FILEMARK) {
961 				if ((bp->b_flags & B_READ) == B_WRITE) {
962 					/*
963 					 * Handling of ST_AT_FILEMARK in
964 					 * st_space will fill in the right file
965 					 * mark count.
966 					 * Back up over filemark
967 					 */
968 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
969 						bp->b_flags |= B_ERROR;
970 						bp->b_resid = bp->b_bcount;
971 						bp->b_error = EIO;
972 						biodone(bp);
973 						continue;
974 					}
975 				} else {
976 					bp->b_resid = bp->b_bcount;
977 					bp->b_error = 0;
978 					bp->b_flags &= ~B_ERROR;
979 					st->flags &= ~ST_AT_FILEMARK;
980 					biodone(bp);
981 					continue;	/* seek more work */
982 				}
983 			}
984 			/*
985 			 * If we are at EIO (e.g. EOM) but have not reported it
986 			 * yet then we should report it now
987 			 */
988 			if (st->flags & ST_EIO_PENDING) {
989 				bp->b_resid = bp->b_bcount;
990 				bp->b_error = EIO;
991 				bp->b_flags |= B_ERROR;
992 				st->flags &= ~ST_EIO_PENDING;
993 				biodone(bp);
994 				continue;	/* seek more work */
995 			}
996 		}
997 
998 		/*
999 		 *  Fill out the scsi command
1000 		 */
1001 		bzero(&cmd, sizeof(cmd));
1002 		if ((bp->b_flags & B_READ) == B_WRITE) {
1003 			cmd.opcode = WRITE;
1004 			st->flags &= ~ST_FM_WRITTEN;
1005 			st->flags |= ST_WRITTEN;
1006 			flags = SCSI_DATA_OUT;
1007 		} else {
1008 			cmd.opcode = READ;
1009 			flags = SCSI_DATA_IN;
1010 		}
1011 
1012 		/*
1013 		 * Handle "fixed-block-mode" tape drives by using the
1014 		 * block count instead of the length.
1015 		 */
1016 		if (st->flags & ST_FIXEDBLOCKS) {
1017 			cmd.byte2 |= SRW_FIXED;
1018 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1019 		} else
1020 			_lto3b(bp->b_bcount, cmd.len);
1021 
1022 		/*
1023 		 * go ask the adapter to do all this for us
1024 		 */
1025 		if (scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1026 		    sizeof(cmd), (u_char *) bp->b_data, bp->b_bcount, 0,
1027 		    100000, bp, flags | SCSI_NOSLEEP))
1028 			printf("%s: not queued\n", st->sc_dev.dv_xname);
1029 	} /* go back and see if we can cram more work in.. */
1030 }
1031 
1032 int
1033 stread(dev, uio, iomode)
1034 	dev_t dev;
1035 	struct uio *uio;
1036 	int iomode;
1037 {
1038 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1039 
1040 	return (physio(ststrategy, NULL, dev, B_READ,
1041 		       st->sc_link->adapter->scsi_minphys, uio));
1042 }
1043 
1044 int
1045 stwrite(dev, uio, iomode)
1046 	dev_t dev;
1047 	struct uio *uio;
1048 	int iomode;
1049 {
1050 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1051 
1052 	return (physio(ststrategy, NULL, dev, B_WRITE,
1053 		       st->sc_link->adapter->scsi_minphys, uio));
1054 }
1055 
1056 /*
1057  * Perform special action on behalf of the user;
1058  * knows about the internals of this device
1059  */
1060 int
1061 stioctl(dev, cmd, arg, flag, p)
1062 	dev_t dev;
1063 	u_long cmd;
1064 	caddr_t arg;
1065 	int flag;
1066 	struct proc *p;
1067 {
1068 	int error = 0;
1069 	int unit;
1070 	int number, nmarks, dsty;
1071 	int flags;
1072 	struct st_softc *st;
1073 	int hold_blksize;
1074 	u_int8_t hold_density;
1075 	struct mtop *mt = (struct mtop *) arg;
1076 
1077 	/*
1078 	 * Find the device that the user is talking about
1079 	 */
1080 	flags = 0;		/* give error messages, act on errors etc. */
1081 	unit = STUNIT(dev);
1082 	dsty = STDSTY(dev);
1083 	st = st_cd.cd_devs[unit];
1084 	hold_blksize = st->blksize;
1085 	hold_density = st->density;
1086 
1087 	switch (cmd) {
1088 
1089 	case MTIOCGET: {
1090 		struct mtget *g = (struct mtget *) arg;
1091 
1092 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1093 		bzero(g, sizeof(struct mtget));
1094 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1095 		g->mt_blksiz = st->blksize;
1096 		g->mt_density = st->density;
1097 		g->mt_mblksiz[0] = st->modes[0].blksize;
1098 		g->mt_mblksiz[1] = st->modes[1].blksize;
1099 		g->mt_mblksiz[2] = st->modes[2].blksize;
1100 		g->mt_mblksiz[3] = st->modes[3].blksize;
1101 		g->mt_mdensity[0] = st->modes[0].density;
1102 		g->mt_mdensity[1] = st->modes[1].density;
1103 		g->mt_mdensity[2] = st->modes[2].density;
1104 		g->mt_mdensity[3] = st->modes[3].density;
1105 		break;
1106 	}
1107 	case MTIOCTOP: {
1108 
1109 		SC_DEBUG(st->sc_link, SDEV_DB1,
1110 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op, mt->mt_count));
1111 
1112 		/* compat: in U*x it is a short */
1113 		number = mt->mt_count;
1114 		switch ((short) (mt->mt_op)) {
1115 		case MTWEOF:	/* write an end-of-file record */
1116 			error = st_write_filemarks(st, number, flags);
1117 			break;
1118 		case MTBSF:	/* backward space file */
1119 			number = -number;
1120 		case MTFSF:	/* forward space file */
1121 			error = st_check_eod(st, FALSE, &nmarks, flags);
1122 			if (!error)
1123 				error = st_space(st, number - nmarks,
1124 				    SP_FILEMARKS, flags);
1125 			break;
1126 		case MTBSR:	/* backward space record */
1127 			number = -number;
1128 		case MTFSR:	/* forward space record */
1129 			error = st_check_eod(st, TRUE, &nmarks, flags);
1130 			if (!error)
1131 				error = st_space(st, number, SP_BLKS, flags);
1132 			break;
1133 		case MTREW:	/* rewind */
1134 			error = st_rewind(st, 0, flags);
1135 			break;
1136 		case MTOFFL:	/* rewind and put the drive offline */
1137 			st_unmount(st, EJECT);
1138 			break;
1139 		case MTNOP:	/* no operation, sets status only */
1140 			break;
1141 		case MTRETEN:	/* retension the tape */
1142 			error = st_load(st, LD_RETENSION, flags);
1143 			if (!error)
1144 				error = st_load(st, LD_LOAD, flags);
1145 			break;
1146 		case MTEOM:	/* forward space to end of media */
1147 			error = st_check_eod(st, FALSE, &nmarks, flags);
1148 			if (!error)
1149 				error = st_space(st, 1, SP_EOM, flags);
1150 			break;
1151 		case MTCACHE:	/* enable controller cache */
1152 			st->flags &= ~ST_DONTBUFFER;
1153 			goto try_new_value;
1154 		case MTNOCACHE:	/* disable controller cache */
1155 			st->flags |= ST_DONTBUFFER;
1156 			goto try_new_value;
1157 		case MTERASE:	/* erase volume */
1158 			error = st_erase(st, number, flags);
1159 			break;
1160 		case MTSETBSIZ:	/* Set block size for device */
1161 #ifdef	NOTYET
1162 			if (!(st->flags & ST_NEW_MOUNT)) {
1163 				uprintf("re-mount tape before changing blocksize");
1164 				error = EINVAL;
1165 				break;
1166 			}
1167 #endif
1168 			if (number == 0) {
1169 				st->flags &= ~ST_FIXEDBLOCKS;
1170 			} else {
1171 				if ((st->blkmin || st->blkmax) &&
1172 				    (number < st->blkmin ||
1173 				    number > st->blkmax)) {
1174 					error = EINVAL;
1175 					break;
1176 				}
1177 				st->flags |= ST_FIXEDBLOCKS;
1178 			}
1179 			st->blksize = number;
1180 			st->flags |= ST_BLOCK_SET;	/*XXX */
1181 			goto try_new_value;
1182 
1183 		case MTSETDNSTY:	/* Set density for device and mode */
1184 			if (number > SCSI_2_MAX_DENSITY_CODE) {
1185 				error = EINVAL;
1186 				break;
1187 			} else
1188 				st->density = number;
1189 			goto try_new_value;
1190 
1191 		default:
1192 			error = EINVAL;
1193 		}
1194 		break;
1195 	}
1196 	case MTIOCIEOT:
1197 	case MTIOCEEOT:
1198 		break;
1199 	default:
1200 		if (STMODE(dev) == CTLMODE)
1201 			error = scsi_do_safeioctl(st->sc_link, dev,
1202 			    cmd, arg, flag, p);
1203 		else
1204 			error = ENOTTY;
1205 		break;
1206 	}
1207 	return error;
1208 /*-----------------------------*/
1209 try_new_value:
1210 	/*
1211 	 * Check that the mode being asked for is aggreeable to the
1212 	 * drive. If not, put it back the way it was.
1213 	 */
1214 	if ((error = st_mode_select(st, 0)) != 0) {/* put it back as it was */
1215 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1216 		st->density = hold_density;
1217 		st->blksize = hold_blksize;
1218 		if (st->blksize)
1219 			st->flags |= ST_FIXEDBLOCKS;
1220 		else
1221 			st->flags &= ~ST_FIXEDBLOCKS;
1222 		return error;
1223 	}
1224 	/*
1225 	 * As the drive liked it, if we are setting a new default,
1226 	 * set it into the structures as such.
1227 	 *
1228 	 * The means for deciding this are not finalised yet
1229 	 */
1230 	if (STMODE(dev) == 0x03) {
1231 		/* special mode */
1232 		/* XXX */
1233 		switch ((short) (mt->mt_op)) {
1234 		case MTSETBSIZ:
1235 			st->modes[dsty].blksize = st->blksize;
1236 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1237 			break;
1238 		case MTSETDNSTY:
1239 			st->modes[dsty].density = st->density;
1240 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1241 			break;
1242 		}
1243 	}
1244 	return 0;
1245 }
1246 
1247 /*
1248  * Do a synchronous read.
1249  */
1250 int
1251 st_read(st, buf, size, flags)
1252 	struct st_softc *st;
1253 	int size;
1254 	int flags;
1255 	char *buf;
1256 {
1257 	struct scsi_rw_tape cmd;
1258 
1259 	/*
1260 	 * If it's a null transfer, return immediatly
1261 	 */
1262 	if (size == 0)
1263 		return 0;
1264 	bzero(&cmd, sizeof(cmd));
1265 	cmd.opcode = READ;
1266 	if (st->flags & ST_FIXEDBLOCKS) {
1267 		cmd.byte2 |= SRW_FIXED;
1268 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1269 		    cmd.len);
1270 	} else
1271 		_lto3b(size, cmd.len);
1272 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1273 	    sizeof(cmd), (u_char *) buf, size, 0, 100000, NULL,
1274 	    flags | SCSI_DATA_IN);
1275 }
1276 
1277 /*
1278  * Ask the drive what it's min and max blk sizes are.
1279  */
1280 int
1281 st_read_block_limits(st, flags)
1282 	struct st_softc *st;
1283 	int flags;
1284 {
1285 	struct scsi_block_limits cmd;
1286 	struct scsi_block_limits_data block_limits;
1287 	struct scsi_link *sc_link = st->sc_link;
1288 	int error;
1289 
1290 	/*
1291 	 * First check if we have it all loaded
1292 	 */
1293 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1294 		return 0;
1295 
1296 	/*
1297 	 * do a 'Read Block Limits'
1298 	 */
1299 	bzero(&cmd, sizeof(cmd));
1300 	cmd.opcode = READ_BLOCK_LIMITS;
1301 
1302 	/*
1303 	 * do the command, update the global values
1304 	 */
1305 	error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1306 			      sizeof(cmd), (u_char *) &block_limits,
1307 			      sizeof(block_limits), ST_RETRIES, 5000,
1308 			      NULL, flags | SCSI_DATA_IN);
1309 	if (error)
1310 		return error;
1311 
1312 	st->blkmin = _2btol(block_limits.min_length);
1313 	st->blkmax = _3btol(block_limits.max_length);
1314 
1315 	SC_DEBUG(sc_link, SDEV_DB3,
1316 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1317 	return 0;
1318 }
1319 
1320 /*
1321  * Get the scsi driver to send a full inquiry to the
1322  * device and use the results to fill out the global
1323  * parameter structure.
1324  *
1325  * called from:
1326  * attach
1327  * open
1328  * ioctl (to reset original blksize)
1329  */
1330 int
1331 st_mode_sense(st, flags)
1332 	struct st_softc *st;
1333 	int flags;
1334 {
1335 	u_int scsi_sense_len;
1336 	int error;
1337 	struct scsi_mode_sense cmd;
1338 	struct scsi_sense {
1339 		struct scsi_mode_header header;
1340 		struct scsi_blk_desc blk_desc;
1341 		u_char sense_data[MAX_PAGE_0_SIZE];
1342 	} scsi_sense;
1343 	struct scsi_link *sc_link = st->sc_link;
1344 
1345 	scsi_sense_len = 12 + st->page_0_size;
1346 
1347 	/*
1348 	 * Set up a mode sense
1349 	 */
1350 	bzero(&cmd, sizeof(cmd));
1351 	cmd.opcode = MODE_SENSE;
1352 	cmd.length = scsi_sense_len;
1353 
1354 	/*
1355 	 * do the command, but we don't need the results
1356 	 * just print them for our interest's sake, if asked,
1357 	 * or if we need it as a template for the mode select
1358 	 * store it away.
1359 	 */
1360 	error = scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1361 			      sizeof(cmd), (u_char *) &scsi_sense,
1362 			      scsi_sense_len, ST_RETRIES, 5000, NULL,
1363 			      flags | SCSI_DATA_IN);
1364 	if (error)
1365 		return error;
1366 
1367 	st->numblks = _3btol(scsi_sense.blk_desc.nblocks);
1368 	st->media_blksize = _3btol(scsi_sense.blk_desc.blklen);
1369 	st->media_density = scsi_sense.blk_desc.density;
1370 	if (scsi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1371 		st->flags |= ST_READONLY;
1372 	SC_DEBUG(sc_link, SDEV_DB3,
1373 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1374 	    st->media_density, st->media_blksize,
1375 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1376 	SC_DEBUG(sc_link, SDEV_DB3,
1377 	    ("%sbuffered\n",
1378 	    scsi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1379 	if (st->page_0_size)
1380 		bcopy(scsi_sense.sense_data, st->sense_data, st->page_0_size);
1381 	sc_link->flags |= SDEV_MEDIA_LOADED;
1382 	return 0;
1383 }
1384 
1385 /*
1386  * Send a filled out parameter structure to the drive to
1387  * set it into the desire modes etc.
1388  */
1389 int
1390 st_mode_select(st, flags)
1391 	struct st_softc *st;
1392 	int flags;
1393 {
1394 	u_int scsi_select_len;
1395 	struct scsi_mode_select cmd;
1396 	struct scsi_select {
1397 		struct scsi_mode_header header;
1398 		struct scsi_blk_desc blk_desc;
1399 		u_char sense_data[MAX_PAGE_0_SIZE];
1400 	} scsi_select;
1401 	struct scsi_link *sc_link = st->sc_link;
1402 
1403 	scsi_select_len = 12 + st->page_0_size;
1404 
1405 	/*
1406 	 * Set up for a mode select
1407 	 */
1408 	bzero(&cmd, sizeof(cmd));
1409 	cmd.opcode = MODE_SELECT;
1410 	cmd.length = scsi_select_len;
1411 
1412 	bzero(&scsi_select, scsi_select_len);
1413 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1414 	scsi_select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
1415 	scsi_select.blk_desc.density = st->density;
1416 	if (st->flags & ST_DONTBUFFER)
1417 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
1418 	else
1419 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1420 	if (st->flags & ST_FIXEDBLOCKS)
1421 		_lto3b(st->blksize, scsi_select.blk_desc.blklen);
1422 	if (st->page_0_size)
1423 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1424 
1425 	/*
1426 	 * do the command
1427 	 */
1428 	return scsi_scsi_cmd(sc_link, (struct scsi_generic *) &cmd,
1429 	    sizeof(cmd), (u_char *) &scsi_select, scsi_select_len,
1430 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1431 }
1432 
1433 /*
1434  * issue an erase command
1435  */
1436 int
1437 st_erase(st, full, flags)
1438 	struct st_softc *st;
1439 	int full, flags;
1440 {
1441 	struct scsi_erase cmd;
1442 
1443 	/*
1444 	 * Full erase means set LONG bit in erase command, which asks
1445 	 * the drive to erase the entire unit.  Without this bit, we're
1446 	 * asking the drive to write an erase gap.
1447 	 */
1448 	bzero(&cmd, sizeof(cmd));
1449 	cmd.opcode = ERASE;
1450 	if (full)
1451 		cmd.byte2 = SE_IMMED|SE_LONG;
1452 	else
1453 		cmd.byte2 = SE_IMMED;
1454 
1455 	/*
1456 	 * XXX We always do this asynchronously, for now.  How long should
1457 	 * we wait if we want to (eventually) to it synchronously?
1458 	 */
1459 	return (scsi_scsi_cmd(st->sc_link, (struct scsi_generic *)&cmd,
1460 	    sizeof(cmd), 0, 0, ST_RETRIES, 5000, NULL, flags));
1461 }
1462 
1463 /*
1464  * skip N blocks/filemarks/seq filemarks/eom
1465  */
1466 int
1467 st_space(st, number, what, flags)
1468 	struct st_softc *st;
1469 	u_int what;
1470 	int flags;
1471 	int number;
1472 {
1473 	struct scsi_space cmd;
1474 	int error;
1475 
1476 	switch (what) {
1477 	case SP_BLKS:
1478 		if (st->flags & ST_PER_ACTION) {
1479 			if (number > 0) {
1480 				st->flags &= ~ST_PER_ACTION;
1481 				return EIO;
1482 			} else if (number < 0) {
1483 				if (st->flags & ST_AT_FILEMARK) {
1484 					/*
1485 					 * Handling of ST_AT_FILEMARK
1486 					 * in st_space will fill in the
1487 					 * right file mark count.
1488 					 */
1489 					error = st_space(st, 0, SP_FILEMARKS,
1490 						flags);
1491 					if (error)
1492 						return error;
1493 				}
1494 				if (st->flags & ST_BLANK_READ) {
1495 					st->flags &= ~ST_BLANK_READ;
1496 					return EIO;
1497 				}
1498 				st->flags &= ~ST_EIO_PENDING;
1499 			}
1500 		}
1501 		break;
1502 	case SP_FILEMARKS:
1503 		if (st->flags & ST_EIO_PENDING) {
1504 			if (number > 0) {
1505 				/* pretend we just discovered the error */
1506 				st->flags &= ~ST_EIO_PENDING;
1507 				return EIO;
1508 			} else if (number < 0) {
1509 				/* back away from the error */
1510 				st->flags &= ~ST_EIO_PENDING;
1511 			}
1512 		}
1513 		if (st->flags & ST_AT_FILEMARK) {
1514 			st->flags &= ~ST_AT_FILEMARK;
1515 			number--;
1516 		}
1517 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1518 			/* back away from unwritten tape */
1519 			st->flags &= ~ST_BLANK_READ;
1520 			number++;	/* XXX dubious */
1521 		}
1522 		break;
1523 	case SP_EOM:
1524 		if (st->flags & ST_EIO_PENDING) {
1525 			/* pretend we just discovered the error */
1526 			st->flags &= ~ST_EIO_PENDING;
1527 			return EIO;
1528 		}
1529 		if (st->flags & ST_AT_FILEMARK)
1530 			st->flags &= ~ST_AT_FILEMARK;
1531 		break;
1532 	}
1533 	if (number == 0)
1534 		return 0;
1535 
1536 	bzero(&cmd, sizeof(cmd));
1537 	cmd.opcode = SPACE;
1538 	cmd.byte2 = what;
1539 	_lto3b(number, cmd.number);
1540 
1541 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1542 	    sizeof(cmd), 0, 0, 0, 900000, NULL, flags);
1543 }
1544 
1545 /*
1546  * write N filemarks
1547  */
1548 int
1549 st_write_filemarks(st, number, flags)
1550 	struct st_softc *st;
1551 	int flags;
1552 	int number;
1553 {
1554 	struct scsi_write_filemarks cmd;
1555 
1556 	/*
1557 	 * It's hard to write a negative number of file marks.
1558 	 * Don't try.
1559 	 */
1560 	if (number < 0)
1561 		return EINVAL;
1562 	switch (number) {
1563 	case 0:		/* really a command to sync the drive's buffers */
1564 		break;
1565 	case 1:
1566 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1567 			st->flags &= ~ST_WRITTEN;
1568 		else
1569 			st->flags |= ST_FM_WRITTEN;
1570 		st->flags &= ~ST_PER_ACTION;
1571 		break;
1572 	default:
1573 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1574 	}
1575 
1576 	bzero(&cmd, sizeof(cmd));
1577 	cmd.opcode = WRITE_FILEMARKS;
1578 	_lto3b(number, cmd.number);
1579 
1580 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1581 	    sizeof(cmd), 0, 0, 0, 100000, NULL, flags);
1582 }
1583 
1584 /*
1585  * Make sure the right number of file marks is on tape if the
1586  * tape has been written.  If the position argument is true,
1587  * leave the tape positioned where it was originally.
1588  *
1589  * nmarks returns the number of marks to skip (or, if position
1590  * true, which were skipped) to get back original position.
1591  */
1592 int
1593 st_check_eod(st, position, nmarks, flags)
1594 	struct st_softc *st;
1595 	boolean position;
1596 	int *nmarks;
1597 	int flags;
1598 {
1599 	int error;
1600 
1601 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1602 	default:
1603 		*nmarks = 0;
1604 		return 0;
1605 	case ST_WRITTEN:
1606 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1607 		*nmarks = 1;
1608 		break;
1609 	case ST_WRITTEN | ST_2FM_AT_EOD:
1610 		*nmarks = 2;
1611 	}
1612 	error = st_write_filemarks(st, *nmarks, flags);
1613 	if (position && !error)
1614 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1615 	return error;
1616 }
1617 
1618 /*
1619  * load/unload/retension
1620  */
1621 int
1622 st_load(st, type, flags)
1623 	struct st_softc *st;
1624 	u_int type;
1625 	int flags;
1626 {
1627 	struct scsi_load cmd;
1628 
1629 	if (type != LD_LOAD) {
1630 		int error;
1631 		int nmarks;
1632 
1633 		error = st_check_eod(st, FALSE, &nmarks, flags);
1634 		if (error)
1635 			return error;
1636 	}
1637 	if (st->quirks & ST_Q_IGNORE_LOADS)
1638 		return 0;
1639 
1640 	bzero(&cmd, sizeof(cmd));
1641 	cmd.opcode = LOAD;
1642 	cmd.how = type;
1643 
1644 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1645 	    sizeof(cmd), 0, 0, ST_RETRIES, 300000, NULL, flags);
1646 }
1647 
1648 /*
1649  *  Rewind the device
1650  */
1651 int
1652 st_rewind(st, immediate, flags)
1653 	struct st_softc *st;
1654 	u_int immediate;
1655 	int flags;
1656 {
1657 	struct scsi_rewind cmd;
1658 	int error;
1659 	int nmarks;
1660 
1661 	error = st_check_eod(st, FALSE, &nmarks, flags);
1662 	if (error)
1663 		return error;
1664 	st->flags &= ~ST_PER_ACTION;
1665 
1666 	bzero(&cmd, sizeof(cmd));
1667 	cmd.opcode = REWIND;
1668 	cmd.byte2 = immediate;
1669 
1670 	return scsi_scsi_cmd(st->sc_link, (struct scsi_generic *) &cmd,
1671 	    sizeof(cmd), 0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL,
1672 	    flags);
1673 }
1674 
1675 /*
1676  * Look at the returned sense and act on the error and detirmine
1677  * The unix error number to pass back... (0 = report no error)
1678  *                            (-1 = continue processing)
1679  */
1680 int
1681 st_interpret_sense(xs)
1682 	struct scsi_xfer *xs;
1683 {
1684 	struct scsi_link *sc_link = xs->sc_link;
1685 	struct scsi_sense_data *sense = &xs->sense;
1686 	struct buf *bp = xs->bp;
1687 	struct st_softc *st = sc_link->device_softc;
1688 	u_int8_t key;
1689 	int32_t info;
1690 
1691 	/*
1692 	 * Get the sense fields and work out what code
1693 	 */
1694 	if (sense->error_code & SSD_ERRCODE_VALID)
1695 		info = _4btol(sense->info);
1696 	else
1697 		info = xs->datalen;	/* bad choice if fixed blocks */
1698 	if ((sense->error_code & SSD_ERRCODE) != 0x70)
1699 		return -1;	/* let the generic code handle it */
1700 	if (st->flags & ST_FIXEDBLOCKS) {
1701 		xs->resid = info * st->blksize;
1702 		if (sense->flags & SSD_EOM) {
1703 			st->flags |= ST_EIO_PENDING;
1704 			if (bp)
1705 				bp->b_resid = xs->resid;
1706 		}
1707 		if (sense->flags & SSD_FILEMARK) {
1708 			st->flags |= ST_AT_FILEMARK;
1709 			if (bp)
1710 				bp->b_resid = xs->resid;
1711 		}
1712 		if (sense->flags & SSD_ILI) {
1713 			st->flags |= ST_EIO_PENDING;
1714 			if (bp)
1715 				bp->b_resid = xs->resid;
1716 			if (sense->error_code & SSD_ERRCODE_VALID &&
1717 			    (xs->flags & SCSI_SILENT) == 0)
1718 				printf("%s: block wrong size, %d blocks residual\n",
1719 				    st->sc_dev.dv_xname, info);
1720 
1721 			/*
1722 			 * This quirk code helps the drive read
1723 			 * the first tape block, regardless of
1724 			 * format.  That is required for these
1725 			 * drives to return proper MODE SENSE
1726 			 * information.
1727 			 */
1728 			if ((st->quirks & ST_Q_SENSE_HELP) &&
1729 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
1730 				st->blksize -= 512;
1731 		}
1732 		/*
1733 		 * If no data was tranfered, do it immediatly
1734 		 */
1735 		if (xs->resid >= xs->datalen) {
1736 			if (st->flags & ST_EIO_PENDING)
1737 				return EIO;
1738 			if (st->flags & ST_AT_FILEMARK) {
1739 				if (bp)
1740 					bp->b_resid = xs->resid;
1741 				return 0;
1742 			}
1743 		}
1744 	} else {		/* must be variable mode */
1745 		xs->resid = xs->datalen;	/* to be sure */
1746 		if (sense->flags & SSD_EOM)
1747 			return EIO;
1748 		if (sense->flags & SSD_FILEMARK) {
1749 			if (bp)
1750 				bp->b_resid = bp->b_bcount;
1751 			return 0;
1752 		}
1753 		if (sense->flags & SSD_ILI) {
1754 			if (info < 0) {
1755 				/*
1756 				 * the record was bigger than the read
1757 				 */
1758 				if ((xs->flags & SCSI_SILENT) == 0)
1759 					printf("%s: %d-byte record too big\n",
1760 					    st->sc_dev.dv_xname,
1761 					    xs->datalen - info);
1762 				return EIO;
1763 			}
1764 			xs->resid = info;
1765 			if (bp)
1766 				bp->b_resid = info;
1767 		}
1768 	}
1769 	key = sense->flags & SSD_KEY;
1770 
1771 	if (key == 0x8) {
1772 		/*
1773 		 * This quirk code helps the drive read the
1774 		 * first tape block, regardless of format.  That
1775 		 * is required for these drives to return proper
1776 		 * MODE SENSE information.
1777 		 */
1778 		if ((st->quirks & ST_Q_SENSE_HELP) &&
1779 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
1780 			/* still starting */
1781 			st->blksize -= 512;
1782 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
1783 			st->flags |= ST_BLANK_READ;
1784 			xs->resid = xs->datalen;
1785 			if (bp) {
1786 				bp->b_resid = xs->resid;
1787 				/* return an EOF */
1788 			}
1789 			return 0;
1790 		}
1791 	}
1792 	return -1;		/* let the default/generic handler handle it */
1793 }
1794 
1795 /*
1796  * The quirk here is that the drive returns some value to st_mode_sense
1797  * incorrectly until the tape has actually passed by the head.
1798  *
1799  * The method is to set the drive to large fixed-block state (user-specified
1800  * density and 1024-byte blocks), then read and rewind to get it to sense the
1801  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
1802  * work, as a last resort, try variable- length blocks.  The result will be
1803  * the ability to do an accurate st_mode_sense.
1804  *
1805  * We know we can do a rewind because we just did a load, which implies rewind.
1806  * Rewind seems preferable to space backward if we have a virgin tape.
1807  *
1808  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
1809  * error processing, both part of st_interpret_sense.
1810  */
1811 int
1812 st_touch_tape(st)
1813 	struct st_softc *st;
1814 {
1815 	char *buf;
1816 	int readsize;
1817 	int error;
1818 
1819 	buf = malloc(1024, M_TEMP, M_NOWAIT);
1820 	if (!buf)
1821 		return ENOMEM;
1822 
1823 	if ((error = st_mode_sense(st, 0)) != 0)
1824 		goto bad;
1825 	st->blksize = 1024;
1826 	do {
1827 		switch (st->blksize) {
1828 		case 512:
1829 		case 1024:
1830 			readsize = st->blksize;
1831 			st->flags |= ST_FIXEDBLOCKS;
1832 			break;
1833 		default:
1834 			readsize = 1;
1835 			st->flags &= ~ST_FIXEDBLOCKS;
1836 		}
1837 		if ((error = st_mode_select(st, 0)) != 0)
1838 			goto bad;
1839 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
1840 		if ((error = st_rewind(st, 0, 0)) != 0) {
1841 bad:			free(buf, M_TEMP);
1842 			return error;
1843 		}
1844 	} while (readsize != 1 && readsize > st->blksize);
1845 
1846 	free(buf, M_TEMP);
1847 	return 0;
1848 }
1849 
1850 int
1851 stdump(dev, blkno, va, size)
1852 	dev_t dev;
1853 	daddr_t blkno;
1854 	caddr_t va;
1855 	size_t size;
1856 {
1857 
1858 	/* Not implemented. */
1859 	return ENXIO;
1860 }
1861