xref: /netbsd-src/sys/dev/scsipi/st.c (revision a5a68ff5f29de57339ca14f6c671c0a87714f1f8)
1 /*	$NetBSD: st.c,v 1.77 1997/10/01 18:45:02 mjacob 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 "opt_scsiverbose.h"
57 
58 #include <sys/types.h>
59 #include <sys/param.h>
60 #include <sys/systm.h>
61 #include <sys/fcntl.h>
62 #include <sys/errno.h>
63 #include <sys/ioctl.h>
64 #include <sys/malloc.h>
65 #include <sys/buf.h>
66 #include <sys/proc.h>
67 #include <sys/user.h>
68 #include <sys/mtio.h>
69 #include <sys/device.h>
70 #include <sys/conf.h>
71 
72 #include <dev/scsipi/scsi_all.h>
73 #include <dev/scsipi/scsipi_all.h>
74 #include <dev/scsipi/scsi_all.h>
75 #include <dev/scsipi/scsi_tape.h>
76 #include <dev/scsipi/scsiconf.h>
77 
78 /* Defines for device specific stuff */
79 #define DEF_FIXED_BSIZE  512
80 #define	ST_RETRIES	4	/* only on non IO commands */
81 
82 #define STMODE(z)	( minor(z)       & 0x03)
83 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
84 #define STUNIT(z)	((minor(z) >> 4)       )
85 #define CTLMODE		3
86 
87 /*
88  * Maximum density code known.
89  */
90 #define SCSI_2_MAX_DENSITY_CODE	0x45
91 
92 /*
93  * Define various devices that we know mis-behave in some way,
94  * and note how they are bad, so we can correct for them
95  */
96 struct modes {
97 	u_int quirks;			/* same definitions as in quirkdata */
98 	int blksize;
99 	u_int8_t density;
100 };
101 
102 struct quirkdata {
103 	u_int quirks;
104 #define	ST_Q_FORCE_BLKSIZE	0x0001
105 #define	ST_Q_SENSE_HELP		0x0002	/* must do READ for good MODE SENSE */
106 #define	ST_Q_IGNORE_LOADS	0x0004
107 #define	ST_Q_BLKSIZE		0x0008	/* variable-block media_blksize > 0 */
108 #define	ST_Q_UNIMODAL		0x0010	/* unimode drive rejects mode select */
109 	u_int page_0_size;
110 #define	MAX_PAGE_0_SIZE	64
111 	struct modes modes[4];
112 };
113 
114 struct st_quirk_inquiry_pattern {
115 	struct scsipi_inquiry_pattern pattern;
116 	struct quirkdata quirkdata;
117 };
118 
119 struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
120 	{{T_SEQUENTIAL, T_REMOV,
121 	 "        ", "                ", "    "}, {0, 0, {
122 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
123 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
124 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
125 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
126 	}}},
127 	{{T_SEQUENTIAL, T_REMOV,
128 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
129 		{0, 0, 0},				/* minor 0-3 */
130 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
131 		{0, 0, QIC_150},			/* minor 8-11 */
132 		{0, 0, QIC_120}				/* minor 12-15 */
133 	}}},
134  	{{T_SEQUENTIAL, T_REMOV,
135  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
136 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
137 		{0, 0, QIC_525},			/* minor 4-7 */
138 		{0, 0, QIC_150},			/* minor 8-11 */
139 		{0, 0, QIC_120}				/* minor 12-15 */
140 	}}},
141 	/*
142 	 * At least -005 and -007 need this.  I'll assume they all do unless I
143 	 * hear otherwise.  - mycroft, 31MAR1994
144 	 */
145 	{{T_SEQUENTIAL, T_REMOV,
146 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
147 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
148 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
149 		{0, 0, QIC_150},			/* minor 8-11 */
150 		{0, 0, QIC_120}				/* minor 12-15 */
151 	}}},
152 	/*
153 	 * One user reports that this works for his tape drive.  It probably
154 	 * needs more work.  - mycroft, 09APR1994
155 	 */
156 	{{T_SEQUENTIAL, T_REMOV,
157 	 "SANKYO  ", "CP525           ", ""},    {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 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
165 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
166 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
167 		{0, 0, QIC_150},			/* minor 8-11 */
168 		{0, 0, QIC_120}				/* minor 12-15 */
169 	}}},
170 	{{T_SEQUENTIAL, T_REMOV,
171 	 "ARCHIVE ", "VIPER 150  21247", ""},     {0, 12, {
172 		{0, 0, 0},				/* minor 0-3 */
173 		{0, 0, QIC_150},			/* minor 4-7 */
174 		{0, 0, QIC_120},			/* minor 8-11 */
175 		{0, 0, QIC_24}				/* minor 12-15 */
176 	}}},
177 	{{T_SEQUENTIAL, T_REMOV,
178 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
179 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
180 		{0, 0, QIC_11},				/* minor 4-7 */
181 		{0, 0, QIC_24},				/* minor 8-11 */
182 		{0, 0, QIC_24}				/* minor 12-15 */
183 	}}},
184 	{{T_SEQUENTIAL, T_REMOV,
185 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
186 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
187 		{0, 0, QIC_24},				/* minor 4-7 */
188 		{0, 0, QIC_120},			/* minor 8-11 */
189 		{0, 0, QIC_150}				/* minor 12-15 */
190 	}}},
191 	{{T_SEQUENTIAL, T_REMOV,
192 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
193 		{0, 0, 0},				/* minor 0-3 */
194 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
195 		{0, 0, QIC_150},			/* minor 8-11 */
196 		{0, 0, QIC_120}				/* minor 12-15 */
197 	}}},
198 	{{T_SEQUENTIAL, T_REMOV,
199 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
200 		{0, 0, 0},				/* minor 0-3 */
201 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
202 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
203 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
204 	}}},
205 	{{T_SEQUENTIAL, T_REMOV,
206 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
207 		{0, 0, 0},				/* minor 0-3 */
208 		{0, 0, 0},				/* minor 4-7 */
209 		{0, 0, 0},				/* minor 8-11 */
210 		{0, 0, 0}				/* minor 12-15 */
211 	}}},
212 	{{T_SEQUENTIAL, T_REMOV,
213 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
214 		{0, 0, QIC_3095},			/* minor 0-3 */
215 		{0, 0, QIC_3095},			/* minor 4-7 */
216 		{0, 0, QIC_3095},			/* minor 8-11 */
217 		{0, 0, QIC_3095},			/* minor 12-15 */
218 	}}},
219 #if 0
220 	{{T_SEQUENTIAL, T_REMOV,
221 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
222 		{0, 0, 0},				/* minor 0-3 */
223 		{0, 0, 0},				/* minor 4-7 */
224 		{0, 0, 0},				/* minor 8-11 */
225 		{0, 0, 0}				/* minor 12-15 */
226 	}}},
227 #endif
228 };
229 
230 #define NOEJECT 0
231 #define EJECT 1
232 
233 struct st_softc {
234 	struct device sc_dev;
235 /*--------------------present operating parameters, flags etc.---------------*/
236 	int flags;		/* see below                         */
237 	u_int quirks;		/* quirks for the open mode          */
238 	int blksize;		/* blksize we are using              */
239 	u_int8_t density;	/* present density                   */
240 	u_int page_0_size;	/* size of page 0 data		     */
241 	u_int last_dsty;	/* last density opened               */
242 /*--------------------device/scsi parameters---------------------------------*/
243 	struct scsipi_link *sc_link;	/* our link to the adpter etc.       */
244 /*--------------------parameters reported by the device ---------------------*/
245 	int blkmin;		/* min blk size                       */
246 	int blkmax;		/* max blk size                       */
247 	struct quirkdata *quirkdata;	/* if we have a rogue entry          */
248 /*--------------------parameters reported by the device for this media-------*/
249 	u_long numblks;		/* nominal blocks capacity            */
250 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
251 	u_int8_t media_density;	/* this is what it said when asked    */
252 /*--------------------quirks for the whole drive-----------------------------*/
253 	u_int drive_quirks;	/* quirks of this drive               */
254 /*--------------------How we should set up when opening each minor device----*/
255 	struct modes modes[4];	/* plus more for each mode            */
256 	u_int8_t  modeflags[4];	/* flags for the modes                */
257 #define DENSITY_SET_BY_USER	0x01
258 #define DENSITY_SET_BY_QUIRK	0x02
259 #define BLKSIZE_SET_BY_USER	0x04
260 #define BLKSIZE_SET_BY_QUIRK	0x08
261 /*--------------------storage for sense data returned by the drive-----------*/
262 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
263 						 * additional sense data needed
264 						 * for mode sense/select.
265 						 */
266 	struct buf buf_queue;		/* the queue of pending IO */
267 					/* operations */
268 };
269 
270 
271 #ifdef __BROKEN_INDIRECT_CONFIG
272 int	stmatch __P((struct device *, void *, void *));
273 #else
274 int	stmatch __P((struct device *, struct cfdata *, void *));
275 #endif
276 void	stattach __P((struct device *, struct device *, void *));
277 void	st_identify_drive __P((struct st_softc *,
278 	    struct scsipi_inquiry_pattern *));
279 void	st_loadquirks __P((struct st_softc *));
280 int	st_mount_tape __P((dev_t, int));
281 void	st_unmount __P((struct st_softc *, boolean));
282 int	st_decide_mode __P((struct st_softc *, boolean));
283 void	ststart __P((void *));
284 int	st_read __P((struct st_softc *, char *, int, int));
285 int	st_read_block_limits __P((struct st_softc *, int));
286 int	st_mode_sense __P((struct st_softc *, int));
287 int	st_mode_select __P((struct st_softc *, int));
288 int	st_cmprss __P((struct st_softc *, int));
289 int	st_space __P((struct st_softc *, int, u_int, int));
290 int	st_write_filemarks __P((struct st_softc *, int, int));
291 int	st_check_eod __P((struct st_softc *, boolean, int *, int));
292 int	st_load __P((struct st_softc *, u_int, int));
293 int	st_rewind __P((struct st_softc *, u_int, int));
294 int	st_interpret_sense __P((struct scsipi_xfer *));
295 int	st_touch_tape __P((struct st_softc *));
296 int	st_erase __P((struct st_softc *, int full, int flags));
297 int	st_rdpos __P((struct st_softc *, int, u_int32_t *));
298 int	st_setpos __P((struct st_softc *, int, u_int32_t *));
299 
300 struct cfattach st_ca = {
301 	sizeof(struct st_softc), stmatch, stattach
302 };
303 
304 struct cfdriver st_cd = {
305 	NULL, "st", DV_TAPE
306 };
307 
308 struct scsipi_device st_switch = {
309 	st_interpret_sense,
310 	ststart,
311 	NULL,
312 	NULL,
313 };
314 
315 #define	ST_INFO_VALID	0x0001
316 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
317 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
318 #define	ST_FIXEDBLOCKS	0x0008
319 #define	ST_AT_FILEMARK	0x0010
320 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
321 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode             */
322 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
323 #define	ST_FM_WRITTEN	0x0100	/*
324 				 * EOF file mark written  -- used with
325 				 * ~ST_WRITTEN to indicate that multiple file
326 				 * marks have been written
327 				 */
328 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
329 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
330 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
331 #define	ST_DONTBUFFER	0x1000	/* Disable buffering/caching */
332 
333 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
334 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN |	\
335 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN |	\
336 			 ST_2FM_AT_EOD | ST_PER_ACTION)
337 
338 struct scsipi_inquiry_pattern st_patterns[] = {
339 	{T_SEQUENTIAL, T_REMOV,
340 	 "",         "",                 ""},
341 };
342 
343 int
344 stmatch(parent, match, aux)
345 	struct device *parent;
346 #ifdef __BROKEN_INDIRECT_CONFIG
347 	void *match;
348 #else
349 	struct cfdata *match;
350 #endif
351 	void *aux;
352 {
353 	struct scsipibus_attach_args *sa = aux;
354 	int priority;
355 
356 	(void)scsipi_inqmatch(&sa->sa_inqbuf,
357 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
358 	    sizeof(st_patterns[0]), &priority);
359 	return (priority);
360 }
361 
362 /*
363  * The routine called by the low level scsi routine when it discovers
364  * A device suitable for this driver
365  */
366 void
367 stattach(parent, self, aux)
368 	struct device *parent, *self;
369 	void *aux;
370 {
371 	struct st_softc *st = (void *)self;
372 	struct scsipibus_attach_args *sa = aux;
373 	struct scsipi_link *sc_link = sa->sa_sc_link;
374 
375 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
376 
377 	/*
378 	 * Store information needed to contact our base driver
379 	 */
380 	st->sc_link = sc_link;
381 	sc_link->device = &st_switch;
382 	sc_link->device_softc = st;
383 	sc_link->openings = 1;
384 
385 	/*
386 	 * Check if the drive is a known criminal and take
387 	 * Any steps needed to bring it into line
388 	 */
389 	st_identify_drive(st, &sa->sa_inqbuf);
390 
391 	/*
392 	 * Use the subdriver to request information regarding
393 	 * the drive. We cannot use interrupts yet, so the
394 	 * request must specify this.
395 	 */
396 	printf("\n");
397 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
398 	if (scsipi_test_unit_ready(sc_link,
399 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
400 	    st_mode_sense(st,
401 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
402 		printf("drive empty\n");
403 	else {
404 		printf("density code 0x%x, ", st->media_density);
405 		if (st->media_blksize > 0)
406 			printf("%d-byte", st->media_blksize);
407 		else
408 			printf("variable");
409 		printf(" blocks, write-%s\n",
410 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
411 	}
412 
413 	/*
414 	 * Set up the buf queue for this device
415 	 */
416 	st->buf_queue.b_active = 0;
417 	st->buf_queue.b_actf = 0;
418 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
419 }
420 
421 /*
422  * Use the inquiry routine in 'scsi_base' to get drive info so we can
423  * Further tailor our behaviour.
424  */
425 void
426 st_identify_drive(st, inqbuf)
427 	struct st_softc *st;
428 	struct scsipi_inquiry_pattern *inqbuf;
429 {
430 	struct st_quirk_inquiry_pattern *finger;
431 	int priority;
432 
433 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
434 	    (caddr_t)st_quirk_patterns,
435 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
436 	    sizeof(st_quirk_patterns[0]), &priority);
437 	if (priority != 0) {
438 		st->quirkdata = &finger->quirkdata;
439 		st->drive_quirks = finger->quirkdata.quirks;
440 		st->quirks = finger->quirkdata.quirks;	/* start value */
441 		st->page_0_size = finger->quirkdata.page_0_size;
442 		st_loadquirks(st);
443 	}
444 }
445 
446 /*
447  * initialise the subdevices to the default (QUIRK) state.
448  * this will remove any setting made by the system operator or previous
449  * operations.
450  */
451 void
452 st_loadquirks(st)
453 	struct st_softc *st;
454 {
455 	int i;
456 	struct	modes *mode;
457 	struct	modes *mode2;
458 
459 	mode = st->quirkdata->modes;
460 	mode2 = st->modes;
461 	for (i = 0; i < 4; i++) {
462 		bzero(mode2, sizeof(struct modes));
463 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
464 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
465 		    DENSITY_SET_BY_USER);
466 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
467 			mode2->blksize = mode->blksize;
468 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
469 		}
470 		if (mode->density) {
471 			mode2->density = mode->density;
472 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
473 		}
474 		mode++;
475 		mode2++;
476 	}
477 }
478 
479 /*
480  * open the device.
481  */
482 int
483 stopen(dev, flags, mode, p)
484 	dev_t dev;
485 	int flags;
486 	int mode;
487 	struct proc *p;
488 {
489 	int unit;
490 	u_int stmode, dsty;
491 	int error = 0;
492 	struct st_softc *st;
493 	struct scsipi_link *sc_link;
494 
495 	unit = STUNIT(dev);
496 	if (unit >= st_cd.cd_ndevs)
497 		return (ENXIO);
498 	st = st_cd.cd_devs[unit];
499 	if (st == NULL)
500 		return (ENXIO);
501 
502 	stmode = STMODE(dev);
503 	dsty = STDSTY(dev);
504 	sc_link = st->sc_link;
505 
506 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
507 	    unit, st_cd.cd_ndevs));
508 
509 	/*
510 	 * Only allow one at a time
511 	 */
512 	if (sc_link->flags & SDEV_OPEN) {
513 		printf("%s: already open\n", st->sc_dev.dv_xname);
514 		return (EBUSY);
515 	}
516 
517 	/*
518 	 * Catch any unit attention errors.
519 	 */
520 	error = scsipi_test_unit_ready(sc_link, SCSI_IGNORE_MEDIA_CHANGE |
521 	    (stmode == CTLMODE ? SCSI_IGNORE_NOT_READY : 0));
522 	if (error)
523 		goto bad;
524 
525 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
526 
527 	/*
528 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
529 	 * then the device has been opened to set defaults
530 	 * This mode does NOT ALLOW I/O, only ioctls
531 	 */
532 	if (stmode == CTLMODE)
533 		return (0);
534 
535 	/*
536 	 * if it's a different mode, or if the media has been
537 	 * invalidated, unmount the tape from the previous
538 	 * session but continue with open processing
539 	 */
540 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
541 		st_unmount(st, NOEJECT);
542 
543 	/*
544 	 * If we are not mounted, then we should start a new
545 	 * mount session.
546 	 */
547 	if (!(st->flags & ST_MOUNTED)) {
548 		st_mount_tape(dev, flags);
549 		st->last_dsty = dsty;
550 	}
551 
552 	/*
553 	 * Make sure that a tape opened in write-only mode will have
554 	 * file marks written on it when closed, even if not written to.
555 	 * This is for SUN compatibility
556 	 */
557 	if ((flags & O_ACCMODE) == FWRITE)
558 		st->flags |= ST_WRITTEN;
559 
560 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
561 	return (0);
562 
563 bad:
564 	st_unmount(st, NOEJECT);
565 	sc_link->flags &= ~SDEV_OPEN;
566 	return (error);
567 }
568 
569 /*
570  * close the device.. only called if we are the LAST
571  * occurence of an open device
572  */
573 int
574 stclose(dev, flags, mode, p)
575 	dev_t dev;
576 	int flags;
577 	int mode;
578 	struct proc *p;
579 {
580 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
581 
582 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
583 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
584 		st_write_filemarks(st, 1, 0);
585 	switch (STMODE(dev)) {
586 	case 0:
587 	case 3:		/* for now */
588 		st_unmount(st, NOEJECT);
589 		break;
590 	case 1:
591 		/* leave mounted unless media seems to have been removed */
592 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
593 			st_unmount(st, NOEJECT);
594 		break;
595 	case 2:
596 		st_unmount(st, EJECT);
597 		break;
598 	}
599 	st->sc_link->flags &= ~SDEV_OPEN;
600 
601 	return (0);
602 }
603 
604 /*
605  * Start a new mount session.
606  * Copy in all the default parameters from the selected device mode.
607  * and try guess any that seem to be defaulted.
608  */
609 int
610 st_mount_tape(dev, flags)
611 	dev_t dev;
612 	int flags;
613 {
614 	int unit;
615 	u_int mode, dsty;
616 	struct st_softc *st;
617 	struct scsipi_link *sc_link;
618 	int error = 0;
619 
620 	unit = STUNIT(dev);
621 	mode = STMODE(dev);
622 	dsty = STDSTY(dev);
623 	st = st_cd.cd_devs[unit];
624 	sc_link = st->sc_link;
625 
626 	if (st->flags & ST_MOUNTED)
627 		return (0);
628 
629 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
630 	st->flags |= ST_NEW_MOUNT;
631 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
632 	/*
633 	 * If the media is new, then make sure we give it a chance to
634 	 * to do a 'load' instruction.  (We assume it is new.)
635 	 */
636 	if ((error = st_load(st, LD_LOAD, 0)) != 0)
637 		return (error);
638 	/*
639 	 * Throw another dummy instruction to catch
640 	 * 'Unit attention' errors. Some drives appear to give
641 	 * these after doing a Load instruction.
642 	 * (noteably some DAT drives)
643 	 */
644 	scsipi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
645 
646 	/*
647 	 * Some devices can't tell you much until they have been
648 	 * asked to look at the media. This quirk does this.
649 	 */
650 	if (st->quirks & ST_Q_SENSE_HELP)
651 		if ((error = st_touch_tape(st)) != 0)
652 			return (error);
653 	/*
654 	 * Load the physical device parameters
655 	 * loads: blkmin, blkmax
656 	 */
657 	if ((error = st_read_block_limits(st, 0)) != 0)
658 		return (error);
659 	/*
660 	 * Load the media dependent parameters
661 	 * includes: media_blksize,media_density,numblks
662 	 * As we have a tape in, it should be reflected here.
663 	 * If not you may need the "quirk" above.
664 	 */
665 	if ((error = st_mode_sense(st, 0)) != 0)
666 		return (error);
667 	/*
668 	 * If we have gained a permanent density from somewhere,
669 	 * then use it in preference to the one supplied by
670 	 * default by the driver.
671 	 */
672 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
673 		st->density = st->modes[dsty].density;
674 	else
675 		st->density = st->media_density;
676 	/*
677 	 * If we have gained a permanent blocksize
678 	 * then use it in preference to the one supplied by
679 	 * default by the driver.
680 	 */
681 	st->flags &= ~ST_FIXEDBLOCKS;
682 	if (st->modeflags[dsty] &
683 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
684 		st->blksize = st->modes[dsty].blksize;
685 		if (st->blksize)
686 			st->flags |= ST_FIXEDBLOCKS;
687 	} else {
688 		if ((error = st_decide_mode(st, FALSE)) != 0)
689 			return (error);
690 	}
691 	if ((error = st_mode_select(st, 0)) != 0) {
692 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
693 		return (error);
694 	}
695 	scsipi_prevent(sc_link, PR_PREVENT,
696 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
697 	st->flags &= ~ST_NEW_MOUNT;
698 	st->flags |= ST_MOUNTED;
699 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
700 
701 	return (0);
702 }
703 
704 /*
705  * End the present mount session.
706  * Rewind, and optionally eject the tape.
707  * Reset various flags to indicate that all new
708  * operations require another mount operation
709  */
710 void
711 st_unmount(st, eject)
712 	struct st_softc *st;
713 	boolean eject;
714 {
715 	struct scsipi_link *sc_link = st->sc_link;
716 	int nmarks;
717 
718 	if (!(st->flags & ST_MOUNTED))
719 		return;
720 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
721 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
722 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
723 	scsipi_prevent(sc_link, PR_ALLOW,
724 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
725 	if (eject)
726 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
727 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
728 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
729 }
730 
731 /*
732  * Given all we know about the device, media, mode, 'quirks' and
733  * initial operation, make a decision as to how we should be set
734  * to run (regarding blocking and EOD marks)
735  */
736 int
737 st_decide_mode(st, first_read)
738 	struct st_softc *st;
739 	boolean	first_read;
740 {
741 #ifdef SCSIDEBUG
742 	struct scsipi_link *sc_link = st->sc_link;
743 #endif
744 
745 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
746 
747 	/*
748 	 * If the drive can only handle fixed-length blocks and only at
749 	 * one size, perhaps we should just do that.
750 	 */
751 	if (st->blkmin && (st->blkmin == st->blkmax)) {
752 		st->flags |= ST_FIXEDBLOCKS;
753 		st->blksize = st->blkmin;
754 		SC_DEBUG(sc_link, SDEV_DB3,
755 		    ("blkmin == blkmax of %d\n", st->blkmin));
756 		goto done;
757 	}
758 	/*
759 	 * If the tape density mandates (or even suggests) use of fixed
760 	 * or variable-length blocks, comply.
761 	 */
762 	switch (st->density) {
763 	case HALFINCH_800:
764 	case HALFINCH_1600:
765 	case HALFINCH_6250:
766 	case DDS:
767 		st->flags &= ~ST_FIXEDBLOCKS;
768 		st->blksize = 0;
769 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
770 		goto done;
771 	case QIC_11:
772 	case QIC_24:
773 	case QIC_120:
774 	case QIC_150:
775 	case QIC_525:
776 	case QIC_1320:
777 		st->flags |= ST_FIXEDBLOCKS;
778 		if (st->media_blksize > 0)
779 			st->blksize = st->media_blksize;
780 		else
781 			st->blksize = DEF_FIXED_BSIZE;
782 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
783 		goto done;
784 	}
785 	/*
786 	 * If we're about to read the tape, perhaps we should choose
787 	 * fixed or variable-length blocks and block size according to
788 	 * what the drive found on the tape.
789 	 */
790 	if (first_read &&
791 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
792 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
793 	    (st->media_blksize == 1024))) {
794 		if (st->media_blksize > 0)
795 			st->flags |= ST_FIXEDBLOCKS;
796 		else
797 			st->flags &= ~ST_FIXEDBLOCKS;
798 		st->blksize = st->media_blksize;
799 		SC_DEBUG(sc_link, SDEV_DB3,
800 		    ("Used media_blksize of %d\n", st->media_blksize));
801 		goto done;
802 	}
803 	/*
804 	 * We're getting no hints from any direction.  Choose variable-
805 	 * length blocks arbitrarily.
806 	 */
807 	st->flags &= ~ST_FIXEDBLOCKS;
808 	st->blksize = 0;
809 	SC_DEBUG(sc_link, SDEV_DB3,
810 	    ("Give up and default to variable mode\n"));
811 
812 done:
813 	/*
814 	 * Decide whether or not to write two file marks to signify end-
815 	 * of-data.  Make the decision as a function of density.  If
816 	 * the decision is not to use a second file mark, the SCSI BLANK
817 	 * CHECK condition code will be recognized as end-of-data when
818 	 * first read.
819 	 * (I think this should be a by-product of fixed/variable..julian)
820 	 */
821 	switch (st->density) {
822 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
823 	case QIC_11:
824 	case QIC_24:
825 	case QIC_120:
826 	case QIC_150:
827 	case QIC_525:
828 	case QIC_1320:
829 		st->flags &= ~ST_2FM_AT_EOD;
830 		break;
831 	default:
832 		st->flags |= ST_2FM_AT_EOD;
833 	}
834 	return (0);
835 }
836 
837 /*
838  * Actually translate the requested transfer into
839  * one the physical driver can understand
840  * The transfer is described by a buf and will include
841  * only one physical transfer.
842  */
843 void
844 ststrategy(bp)
845 	struct buf *bp;
846 {
847 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
848 	struct buf *dp;
849 	int s;
850 
851 	SC_DEBUG(st->sc_link, SDEV_DB1,
852 	    ("ststrategy %ld bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
853 	/*
854 	 * If it's a null transfer, return immediatly
855 	 */
856 	if (bp->b_bcount == 0)
857 		goto done;
858 	/*
859 	 * Odd sized request on fixed drives are verboten
860 	 */
861 	if (st->flags & ST_FIXEDBLOCKS) {
862 		if (bp->b_bcount % st->blksize) {
863 			printf("%s: bad request, must be multiple of %d\n",
864 			    st->sc_dev.dv_xname, st->blksize);
865 			bp->b_error = EIO;
866 			goto bad;
867 		}
868 	}
869 	/*
870 	 * as are out-of-range requests on variable drives.
871 	 */
872 	else if (bp->b_bcount < st->blkmin ||
873 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
874 		printf("%s: bad request, must be between %d and %d\n",
875 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
876 		bp->b_error = EIO;
877 		goto bad;
878 	}
879 	s = splbio();
880 
881 	/*
882 	 * Place it in the queue of activities for this tape
883 	 * at the end (a bit silly because we only have on user..
884 	 * (but it could fork()))
885 	 */
886 	dp = &st->buf_queue;
887 	bp->b_actf = NULL;
888 	bp->b_actb = dp->b_actb;
889 	*dp->b_actb = bp;
890 	dp->b_actb = &bp->b_actf;
891 
892 	/*
893 	 * Tell the device to get going on the transfer if it's
894 	 * not doing anything, otherwise just wait for completion
895 	 * (All a bit silly if we're only allowing 1 open but..)
896 	 */
897 	ststart(st);
898 
899 	splx(s);
900 	return;
901 bad:
902 	bp->b_flags |= B_ERROR;
903 done:
904 	/*
905 	 * Correctly set the buf to indicate a completed xfer
906 	 */
907 	bp->b_resid = bp->b_bcount;
908 	biodone(bp);
909 	return;
910 }
911 
912 /*
913  * ststart looks to see if there is a buf waiting for the device
914  * and that the device is not already busy. If both are true,
915  * It dequeues the buf and creates a scsi command to perform the
916  * transfer required. The transfer request will call scsipi_done
917  * on completion, which will in turn call this routine again
918  * so that the next queued transfer is performed.
919  * The bufs are queued by the strategy routine (ststrategy)
920  *
921  * This routine is also called after other non-queued requests
922  * have been made of the scsi driver, to ensure that the queue
923  * continues to be drained.
924  * ststart() is called at splbio
925  */
926 void
927 ststart(v)
928 	void *v;
929 {
930 	struct st_softc *st = v;
931 	struct scsipi_link *sc_link = st->sc_link;
932 	register struct buf *bp, *dp;
933 	struct scsi_rw_tape cmd;
934 	int flags;
935 
936 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
937 	/*
938 	 * See if there is a buf to do and we are not already
939 	 * doing one
940 	 */
941 	while (sc_link->openings > 0) {
942 		/* if a special awaits, let it proceed first */
943 		if (sc_link->flags & SDEV_WAITING) {
944 			sc_link->flags &= ~SDEV_WAITING;
945 			wakeup((caddr_t)sc_link);
946 			return;
947 		}
948 
949 		dp = &st->buf_queue;
950 		if ((bp = dp->b_actf) == NULL)
951 			return;
952 		if ((dp = bp->b_actf) != NULL)
953 			dp->b_actb = bp->b_actb;
954 		else
955 			st->buf_queue.b_actb = bp->b_actb;
956 		*bp->b_actb = dp;
957 
958 		/*
959 		 * if the device has been unmounted byt the user
960 		 * then throw away all requests until done
961 		 */
962 		if (!(st->flags & ST_MOUNTED) ||
963 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
964 			/* make sure that one implies the other.. */
965 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
966 			bp->b_flags |= B_ERROR;
967 			bp->b_error = EIO;
968 			bp->b_resid = bp->b_bcount;
969 			biodone(bp);
970 			continue;
971 		}
972 		/*
973 		 * only FIXEDBLOCK devices have pending operations
974 		 */
975 		if (st->flags & ST_FIXEDBLOCKS) {
976 			/*
977 			 * If we are at a filemark but have not reported it yet
978 			 * then we should report it now
979 			 */
980 			if (st->flags & ST_AT_FILEMARK) {
981 				if ((bp->b_flags & B_READ) == B_WRITE) {
982 					/*
983 					 * Handling of ST_AT_FILEMARK in
984 					 * st_space will fill in the right file
985 					 * mark count.
986 					 * Back up over filemark
987 					 */
988 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
989 						bp->b_flags |= B_ERROR;
990 						bp->b_error = EIO;
991 						biodone(bp);
992 						continue;
993 					}
994 				} else {
995 					bp->b_resid = bp->b_bcount;
996 					bp->b_error = 0;
997 					bp->b_flags &= ~B_ERROR;
998 					st->flags &= ~ST_AT_FILEMARK;
999 					biodone(bp);
1000 					continue;	/* seek more work */
1001 				}
1002 			}
1003 			/*
1004 			 * If we are at EIO (e.g. EOM) but have not reported it
1005 			 * yet then we should report it now
1006 			 */
1007 			if (st->flags & ST_EIO_PENDING) {
1008 				bp->b_resid = bp->b_bcount;
1009 				bp->b_error = EIO;
1010 				bp->b_flags |= B_ERROR;
1011 				st->flags &= ~ST_EIO_PENDING;
1012 				biodone(bp);
1013 				continue;	/* seek more work */
1014 			}
1015 		}
1016 
1017 		/*
1018 		 *  Fill out the scsi command
1019 		 */
1020 		bzero(&cmd, sizeof(cmd));
1021 		if ((bp->b_flags & B_READ) == B_WRITE) {
1022 			cmd.opcode = WRITE;
1023 			st->flags &= ~ST_FM_WRITTEN;
1024 			st->flags |= ST_WRITTEN;
1025 			flags = SCSI_DATA_OUT;
1026 		} else {
1027 			cmd.opcode = READ;
1028 			flags = SCSI_DATA_IN;
1029 		}
1030 
1031 		/*
1032 		 * Handle "fixed-block-mode" tape drives by using the
1033 		 * block count instead of the length.
1034 		 */
1035 		if (st->flags & ST_FIXEDBLOCKS) {
1036 			cmd.byte2 |= SRW_FIXED;
1037 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1038 		} else
1039 			_lto3b(bp->b_bcount, cmd.len);
1040 
1041 		/*
1042 		 * go ask the adapter to do all this for us
1043 		 */
1044 		if ((*sc_link->scsipi_cmd)(sc_link,
1045 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1046 		    (u_char *)bp->b_data, bp->b_bcount,
1047 		    0, 100000, bp, flags | SCSI_NOSLEEP))
1048 			printf("%s: not queued\n", st->sc_dev.dv_xname);
1049 	} /* go back and see if we can cram more work in.. */
1050 }
1051 
1052 int
1053 stread(dev, uio, iomode)
1054 	dev_t dev;
1055 	struct uio *uio;
1056 	int iomode;
1057 {
1058 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1059 
1060 	return (physio(ststrategy, NULL, dev, B_READ,
1061 	    st->sc_link->adapter->scsipi_minphys, uio));
1062 }
1063 
1064 int
1065 stwrite(dev, uio, iomode)
1066 	dev_t dev;
1067 	struct uio *uio;
1068 	int iomode;
1069 {
1070 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1071 
1072 	return (physio(ststrategy, NULL, dev, B_WRITE,
1073 	    st->sc_link->adapter->scsipi_minphys, uio));
1074 }
1075 
1076 /*
1077  * Perform special action on behalf of the user;
1078  * knows about the internals of this device
1079  */
1080 int
1081 stioctl(dev, cmd, arg, flag, p)
1082 	dev_t dev;
1083 	u_long cmd;
1084 	caddr_t arg;
1085 	int flag;
1086 	struct proc *p;
1087 {
1088 	int error = 0;
1089 	int unit;
1090 	int number, nmarks, dsty;
1091 	int flags;
1092 	struct st_softc *st;
1093 	int hold_blksize;
1094 	u_int8_t hold_density;
1095 	struct mtop *mt = (struct mtop *) arg;
1096 
1097 	/*
1098 	 * Find the device that the user is talking about
1099 	 */
1100 	flags = 0;		/* give error messages, act on errors etc. */
1101 	unit = STUNIT(dev);
1102 	dsty = STDSTY(dev);
1103 	st = st_cd.cd_devs[unit];
1104 	hold_blksize = st->blksize;
1105 	hold_density = st->density;
1106 
1107 	switch ((u_int) cmd) {
1108 
1109 	case MTIOCGET: {
1110 		struct mtget *g = (struct mtget *) arg;
1111 
1112 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1113 		bzero(g, sizeof(struct mtget));
1114 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1115 		g->mt_blksiz = st->blksize;
1116 		g->mt_density = st->density;
1117 		g->mt_mblksiz[0] = st->modes[0].blksize;
1118 		g->mt_mblksiz[1] = st->modes[1].blksize;
1119 		g->mt_mblksiz[2] = st->modes[2].blksize;
1120 		g->mt_mblksiz[3] = st->modes[3].blksize;
1121 		g->mt_mdensity[0] = st->modes[0].density;
1122 		g->mt_mdensity[1] = st->modes[1].density;
1123 		g->mt_mdensity[2] = st->modes[2].density;
1124 		g->mt_mdensity[3] = st->modes[3].density;
1125 		break;
1126 	}
1127 	case MTIOCTOP: {
1128 
1129 		SC_DEBUG(st->sc_link, SDEV_DB1,
1130 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1131 			mt->mt_count));
1132 
1133 		/* compat: in U*x it is a short */
1134 		number = mt->mt_count;
1135 		switch ((short) (mt->mt_op)) {
1136 		case MTWEOF:	/* write an end-of-file record */
1137 			error = st_write_filemarks(st, number, flags);
1138 			break;
1139 		case MTBSF:	/* backward space file */
1140 			number = -number;
1141 		case MTFSF:	/* forward space file */
1142 			error = st_check_eod(st, FALSE, &nmarks, flags);
1143 			if (!error)
1144 				error = st_space(st, number - nmarks,
1145 				    SP_FILEMARKS, flags);
1146 			break;
1147 		case MTBSR:	/* backward space record */
1148 			number = -number;
1149 		case MTFSR:	/* forward space record */
1150 			error = st_check_eod(st, TRUE, &nmarks, flags);
1151 			if (!error)
1152 				error = st_space(st, number, SP_BLKS, flags);
1153 			break;
1154 		case MTREW:	/* rewind */
1155 			error = st_rewind(st, 0, flags);
1156 			break;
1157 		case MTOFFL:	/* rewind and put the drive offline */
1158 			st_unmount(st, EJECT);
1159 			break;
1160 		case MTNOP:	/* no operation, sets status only */
1161 			break;
1162 		case MTRETEN:	/* retension the tape */
1163 			error = st_load(st, LD_RETENSION, flags);
1164 			if (!error)
1165 				error = st_load(st, LD_LOAD, flags);
1166 			break;
1167 		case MTEOM:	/* forward space to end of media */
1168 			error = st_check_eod(st, FALSE, &nmarks, flags);
1169 			if (!error)
1170 				error = st_space(st, 1, SP_EOM, flags);
1171 			break;
1172 		case MTCACHE:	/* enable controller cache */
1173 			st->flags &= ~ST_DONTBUFFER;
1174 			goto try_new_value;
1175 		case MTNOCACHE:	/* disable controller cache */
1176 			st->flags |= ST_DONTBUFFER;
1177 			goto try_new_value;
1178 		case MTERASE:	/* erase volume */
1179 			error = st_erase(st, number, flags);
1180 			break;
1181 		case MTSETBSIZ:	/* Set block size for device */
1182 #ifdef	NOTYET
1183 			if (!(st->flags & ST_NEW_MOUNT)) {
1184 				uprintf("re-mount tape before changing blocksize");
1185 				error = EINVAL;
1186 				break;
1187 			}
1188 #endif
1189 			if (number == 0)
1190 				st->flags &= ~ST_FIXEDBLOCKS;
1191 			else {
1192 				if ((st->blkmin || st->blkmax) &&
1193 				    (number < st->blkmin ||
1194 				    number > st->blkmax)) {
1195 					error = EINVAL;
1196 					break;
1197 				}
1198 				st->flags |= ST_FIXEDBLOCKS;
1199 			}
1200 			st->blksize = number;
1201 			st->flags |= ST_BLOCK_SET;	/*XXX */
1202 			goto try_new_value;
1203 
1204 		case MTSETDNSTY:	/* Set density for device and mode */
1205 			if (number > SCSI_2_MAX_DENSITY_CODE) {
1206 				error = EINVAL;
1207 				break;
1208 			} else
1209 				st->density = number;
1210 			goto try_new_value;
1211 
1212 		case MTCMPRESS:
1213 			error = st_cmprss(st, number);
1214 			break;
1215 
1216 		default:
1217 			error = EINVAL;
1218 		}
1219 		break;
1220 	}
1221 	case MTIOCIEOT:
1222 	case MTIOCEEOT:
1223 		break;
1224 
1225 	case MTIOCRDSPOS:
1226 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1227 		break;
1228 
1229 	case MTIOCRDHPOS:
1230 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1231 		break;
1232 
1233 	case MTIOCSLOCATE:
1234 		error = st_setpos(st, 0, (u_int32_t *) arg);
1235 		break;
1236 
1237 	case MTIOCHLOCATE:
1238 		error = st_setpos(st, 1, (u_int32_t *) arg);
1239 		break;
1240 
1241 	default:
1242 		if (STMODE(dev) == CTLMODE)
1243 			error = scsipi_do_ioctl(st->sc_link, dev, cmd, arg,
1244 			    flag, p);
1245 		else
1246 			error = ENOTTY;
1247 		break;
1248 	}
1249 	return (error);
1250 /*-----------------------------*/
1251 try_new_value:
1252 	/*
1253 	 * Check that the mode being asked for is aggreeable to the
1254 	 * drive. If not, put it back the way it was.
1255 	 */
1256 	if ((error = st_mode_select(st, 0)) != 0) {/* put it back as it was */
1257 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1258 		st->density = hold_density;
1259 		st->blksize = hold_blksize;
1260 		if (st->blksize)
1261 			st->flags |= ST_FIXEDBLOCKS;
1262 		else
1263 			st->flags &= ~ST_FIXEDBLOCKS;
1264 		return (error);
1265 	}
1266 	/*
1267 	 * As the drive liked it, if we are setting a new default,
1268 	 * set it into the structures as such.
1269 	 *
1270 	 * The means for deciding this are not finalised yet
1271 	 */
1272 	if (STMODE(dev) == 0x03) {
1273 		/* special mode */
1274 		/* XXX */
1275 		switch ((short) (mt->mt_op)) {
1276 		case MTSETBSIZ:
1277 			st->modes[dsty].blksize = st->blksize;
1278 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1279 			break;
1280 		case MTSETDNSTY:
1281 			st->modes[dsty].density = st->density;
1282 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1283 			break;
1284 		}
1285 	}
1286 	return (0);
1287 }
1288 
1289 /*
1290  * Do a synchronous read.
1291  */
1292 int
1293 st_read(st, buf, size, flags)
1294 	struct st_softc *st;
1295 	int size;
1296 	int flags;
1297 	char *buf;
1298 {
1299 	struct scsi_rw_tape cmd;
1300 
1301 	/*
1302 	 * If it's a null transfer, return immediatly
1303 	 */
1304 	if (size == 0)
1305 		return (0);
1306 	bzero(&cmd, sizeof(cmd));
1307 	cmd.opcode = READ;
1308 	if (st->flags & ST_FIXEDBLOCKS) {
1309 		cmd.byte2 |= SRW_FIXED;
1310 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1311 		    cmd.len);
1312 	} else
1313 		_lto3b(size, cmd.len);
1314 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1315 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1316 	    (u_char *)buf, size, 0, 100000, NULL, flags | SCSI_DATA_IN));
1317 }
1318 
1319 /*
1320  * Ask the drive what it's min and max blk sizes are.
1321  */
1322 int
1323 st_read_block_limits(st, flags)
1324 	struct st_softc *st;
1325 	int flags;
1326 {
1327 	struct scsi_block_limits cmd;
1328 	struct scsi_block_limits_data block_limits;
1329 	struct scsipi_link *sc_link = st->sc_link;
1330 	int error;
1331 
1332 	/*
1333 	 * First check if we have it all loaded
1334 	 */
1335 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1336 		return (0);
1337 
1338 	/*
1339 	 * do a 'Read Block Limits'
1340 	 */
1341 	bzero(&cmd, sizeof(cmd));
1342 	cmd.opcode = READ_BLOCK_LIMITS;
1343 
1344 	/*
1345 	 * do the command, update the global values
1346 	 */
1347 	error = (*sc_link->scsipi_cmd)(sc_link, (struct scsipi_generic *)&cmd,
1348 	    sizeof(cmd), (u_char *)&block_limits, sizeof(block_limits),
1349 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1350 	if (error)
1351 		return (error);
1352 
1353 	st->blkmin = _2btol(block_limits.min_length);
1354 	st->blkmax = _3btol(block_limits.max_length);
1355 
1356 	SC_DEBUG(sc_link, SDEV_DB3,
1357 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1358 	return (0);
1359 }
1360 
1361 /*
1362  * Get the scsi driver to send a full inquiry to the
1363  * device and use the results to fill out the global
1364  * parameter structure.
1365  *
1366  * called from:
1367  * attach
1368  * open
1369  * ioctl (to reset original blksize)
1370  */
1371 int
1372 st_mode_sense(st, flags)
1373 	struct st_softc *st;
1374 	int flags;
1375 {
1376 	u_int scsipi_sense_len;
1377 	int error;
1378 	struct scsi_mode_sense cmd;
1379 	struct scsipi_sense {
1380 		struct scsi_mode_header header;
1381 		struct scsi_blk_desc blk_desc;
1382 		u_char sense_data[MAX_PAGE_0_SIZE];
1383 	} scsipi_sense;
1384 	struct scsipi_link *sc_link = st->sc_link;
1385 
1386 	scsipi_sense_len = 12 + st->page_0_size;
1387 
1388 	/*
1389 	 * Set up a mode sense
1390 	 */
1391 	bzero(&cmd, sizeof(cmd));
1392 	cmd.opcode = SCSI_MODE_SENSE;
1393 	cmd.length = scsipi_sense_len;
1394 
1395 	/*
1396 	 * do the command, but we don't need the results
1397 	 * just print them for our interest's sake, if asked,
1398 	 * or if we need it as a template for the mode select
1399 	 * store it away.
1400 	 */
1401 	error = (*sc_link->scsipi_cmd)(sc_link, (struct scsipi_generic *)&cmd,
1402 	    sizeof(cmd), (u_char *)&scsipi_sense, scsipi_sense_len,
1403 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1404 	if (error)
1405 		return (error);
1406 
1407 	st->numblks = _3btol(scsipi_sense.blk_desc.nblocks);
1408 	st->media_blksize = _3btol(scsipi_sense.blk_desc.blklen);
1409 	st->media_density = scsipi_sense.blk_desc.density;
1410 	if (scsipi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1411 		st->flags |= ST_READONLY;
1412 	SC_DEBUG(sc_link, SDEV_DB3,
1413 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1414 	    st->media_density, st->media_blksize,
1415 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1416 	SC_DEBUG(sc_link, SDEV_DB3,
1417 	    ("%sbuffered\n",
1418 	    scsipi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1419 	if (st->page_0_size)
1420 		bcopy(scsipi_sense.sense_data, st->sense_data,
1421 		    st->page_0_size);
1422 	sc_link->flags |= SDEV_MEDIA_LOADED;
1423 	return (0);
1424 }
1425 
1426 /*
1427  * Send a filled out parameter structure to the drive to
1428  * set it into the desire modes etc.
1429  */
1430 int
1431 st_mode_select(st, flags)
1432 	struct st_softc *st;
1433 	int flags;
1434 {
1435 	u_int scsi_select_len;
1436 	struct scsi_mode_select cmd;
1437 	struct scsi_select {
1438 		struct scsi_mode_header header;
1439 		struct scsi_blk_desc blk_desc;
1440 		u_char sense_data[MAX_PAGE_0_SIZE];
1441 	} scsi_select;
1442 	struct scsipi_link *sc_link = st->sc_link;
1443 
1444 	scsi_select_len = 12 + st->page_0_size;
1445 
1446 	/*
1447 	 * This quirk deals with drives that have only one valid mode
1448 	 * and think this gives them license to reject all mode selects,
1449 	 * even if the selected mode is the one that is supported.
1450 	 */
1451 	if (st->quirks & ST_Q_UNIMODAL) {
1452 		SC_DEBUG(sc_link, SDEV_DB3,
1453 		    ("not setting density 0x%x blksize 0x%x\n",
1454 		    st->density, st->blksize));
1455 		return (0);
1456 	}
1457 
1458 	/*
1459 	 * Set up for a mode select
1460 	 */
1461 	bzero(&cmd, sizeof(cmd));
1462 	cmd.opcode = SCSI_MODE_SELECT;
1463 	cmd.length = scsi_select_len;
1464 
1465 	bzero(&scsi_select, scsi_select_len);
1466 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1467 	scsi_select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
1468 	scsi_select.blk_desc.density = st->density;
1469 	if (st->flags & ST_DONTBUFFER)
1470 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
1471 	else
1472 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1473 	if (st->flags & ST_FIXEDBLOCKS)
1474 		_lto3b(st->blksize, scsi_select.blk_desc.blklen);
1475 	if (st->page_0_size)
1476 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1477 
1478 	/*
1479 	 * do the command
1480 	 */
1481 	return ((*sc_link->scsipi_cmd)(sc_link, (struct scsipi_generic *)&cmd,
1482 	    sizeof(cmd), (u_char *)&scsi_select, scsi_select_len,
1483 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT));
1484 }
1485 
1486 int
1487 st_cmprss(st, onoff)
1488 	struct st_softc *st;
1489 	int onoff;
1490 {
1491 	u_int scsi_dlen;
1492 	struct scsi_mode_select mcmd;
1493 	struct scsi_mode_sense scmd;
1494 	struct scsi_select {
1495 		struct scsi_mode_header header;
1496 		struct scsi_blk_desc blk_desc;
1497 		u_char pdata[max(sizeof(struct scsi_tape_dev_conf_page),
1498 		    sizeof(struct scsi_tape_dev_compression_page))];
1499 	} scsi_pdata;
1500 	struct scsi_tape_dev_conf_page *ptr;
1501 	struct scsi_tape_dev_compression_page *cptr;
1502 	struct scsipi_link *sc_link = st->sc_link;
1503 	int error, ison, flags;
1504 
1505 	scsi_dlen = sizeof(scsi_pdata);
1506 	bzero(&scsi_pdata, scsi_dlen);
1507 
1508 	/*
1509 	 * Set up for a mode sense.
1510 	 * Do DATA COMPRESSION page first.
1511 	 */
1512 	bzero(&scmd, sizeof(scmd));
1513 	scmd.opcode = SCSI_MODE_SENSE;
1514 	scmd.page = SMS_PAGE_CTRL_CURRENT | 0xf;
1515 	scmd.length = scsi_dlen;
1516 
1517 	flags = SCSI_SILENT;
1518 
1519 	/*
1520 	 * Do the MODE SENSE command...
1521 	 */
1522 again:
1523 	error = (*sc_link->scsipi_cmd)(sc_link,
1524 	    (struct scsipi_generic *)&scmd, sizeof(scmd),
1525 	    (u_char *)&scsi_pdata, scsi_dlen,
1526 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1527 
1528 	if (error) {
1529 		if (scmd.byte2 != SMS_DBD) {
1530 			scmd.byte2 = SMS_DBD;
1531 			goto again;
1532 		}
1533 		return (error);
1534 	}
1535 
1536 	if (scsi_pdata.header.blk_desc_len)
1537 		ptr = (struct scsi_tape_dev_conf_page *) scsi_pdata.pdata;
1538 	else
1539 		ptr = (struct scsi_tape_dev_conf_page *) &scsi_pdata.blk_desc;
1540 
1541 	if ((scmd.page & SMS_PAGE_CODE) == 0xf) {
1542 		cptr = (struct scsi_tape_dev_compression_page *) ptr;
1543 		ison = (cptr->dce_dcc & DCP_DCE) != 0;
1544 		if (onoff)
1545 			cptr->dce_dcc |= DCP_DCE;
1546 		else
1547 			cptr->dce_dcc &= ~DCP_DCE;
1548 		cptr->pagecode &= ~0x80;
1549 	} else {
1550 		ison =  (ptr->sel_comp_alg != 0);
1551 		if (onoff)
1552 			ptr->sel_comp_alg = 1;
1553 		else
1554 			ptr->sel_comp_alg = 0;
1555 		ptr->pagecode &= ~0x80;
1556 	}
1557 	onoff = onoff ? 1 : 0;
1558 	/*
1559 	 * There might be a virtue in actually doing the MODE SELECTS,
1560 	 * but let's not clog the bus over it.
1561 	 */
1562 	if (onoff == ison)
1563 		return (0);
1564 
1565 	/*
1566 	 * Set up for a mode select
1567 	 */
1568 
1569 	scsi_pdata.header.data_length = 0;
1570 	scsi_pdata.header.medium_type = 0;
1571 	if ((st->flags & ST_DONTBUFFER) == 0)
1572 		scsi_pdata.header.dev_spec = SMH_DSP_BUFF_MODE_ON;
1573 	else
1574 		scsi_pdata.header.dev_spec = 0;
1575 
1576 	bzero(&mcmd, sizeof(mcmd));
1577 	mcmd.opcode = SCSI_MODE_SELECT;
1578 	mcmd.byte2 = SMS_PF;
1579 	mcmd.length = scsi_dlen;
1580 	if (scsi_pdata.header.blk_desc_len) {
1581 		scsi_pdata.blk_desc.density = 0;
1582 		scsi_pdata.blk_desc.nblocks[0] = 0;
1583 		scsi_pdata.blk_desc.nblocks[1] = 0;
1584 		scsi_pdata.blk_desc.nblocks[2] = 0;
1585 	}
1586 
1587 	/*
1588 	 * Do the command
1589 	 */
1590 	error = (*sc_link->scsipi_cmd)(sc_link,
1591 	    (struct scsipi_generic *)&mcmd, sizeof(mcmd),
1592 	    (u_char *)&scsi_pdata, scsi_dlen,
1593 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1594 
1595 	if (error && (scmd.page & SMS_PAGE_CODE) == 0xf) {
1596 		/*
1597 		 * Try DEVICE CONFIGURATION page.
1598 		 */
1599 		scmd.page = SMS_PAGE_CTRL_CURRENT | 0x10;
1600 		goto again;
1601 	}
1602 	return (error);
1603 }
1604 /*
1605  * issue an erase command
1606  */
1607 int
1608 st_erase(st, full, flags)
1609 	struct st_softc *st;
1610 	int full, flags;
1611 {
1612 	struct scsi_erase cmd;
1613 
1614 	/*
1615 	 * Full erase means set LONG bit in erase command, which asks
1616 	 * the drive to erase the entire unit.  Without this bit, we're
1617 	 * asking the drive to write an erase gap.
1618 	 */
1619 	bzero(&cmd, sizeof(cmd));
1620 	cmd.opcode = ERASE;
1621 	if (full)
1622 		cmd.byte2 = SE_IMMED|SE_LONG;
1623 	else
1624 		cmd.byte2 = SE_IMMED;
1625 
1626 	/*
1627 	 * XXX We always do this asynchronously, for now.  How long should
1628 	 * we wait if we want to (eventually) to it synchronously?
1629 	 */
1630 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1631 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1632 	    0, 0, ST_RETRIES, 5000, NULL, flags));
1633 }
1634 
1635 /*
1636  * skip N blocks/filemarks/seq filemarks/eom
1637  */
1638 int
1639 st_space(st, number, what, flags)
1640 	struct st_softc *st;
1641 	u_int what;
1642 	int flags;
1643 	int number;
1644 {
1645 	struct scsi_space cmd;
1646 	int error;
1647 
1648 	switch (what) {
1649 	case SP_BLKS:
1650 		if (st->flags & ST_PER_ACTION) {
1651 			if (number > 0) {
1652 				st->flags &= ~ST_PER_ACTION;
1653 				return (EIO);
1654 			} else if (number < 0) {
1655 				if (st->flags & ST_AT_FILEMARK) {
1656 					/*
1657 					 * Handling of ST_AT_FILEMARK
1658 					 * in st_space will fill in the
1659 					 * right file mark count.
1660 					 */
1661 					error = st_space(st, 0, SP_FILEMARKS,
1662 					    flags);
1663 					if (error)
1664 						return (error);
1665 				}
1666 				if (st->flags & ST_BLANK_READ) {
1667 					st->flags &= ~ST_BLANK_READ;
1668 					return (EIO);
1669 				}
1670 				st->flags &= ~ST_EIO_PENDING;
1671 			}
1672 		}
1673 		break;
1674 	case SP_FILEMARKS:
1675 		if (st->flags & ST_EIO_PENDING) {
1676 			if (number > 0) {
1677 				/* pretend we just discovered the error */
1678 				st->flags &= ~ST_EIO_PENDING;
1679 				return (EIO);
1680 			} else if (number < 0) {
1681 				/* back away from the error */
1682 				st->flags &= ~ST_EIO_PENDING;
1683 			}
1684 		}
1685 		if (st->flags & ST_AT_FILEMARK) {
1686 			st->flags &= ~ST_AT_FILEMARK;
1687 			number--;
1688 		}
1689 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1690 			/* back away from unwritten tape */
1691 			st->flags &= ~ST_BLANK_READ;
1692 			number++;	/* XXX dubious */
1693 		}
1694 		break;
1695 	case SP_EOM:
1696 		if (st->flags & ST_EIO_PENDING) {
1697 			/* pretend we just discovered the error */
1698 			st->flags &= ~ST_EIO_PENDING;
1699 			return (EIO);
1700 		}
1701 		if (st->flags & ST_AT_FILEMARK)
1702 			st->flags &= ~ST_AT_FILEMARK;
1703 		break;
1704 	}
1705 	if (number == 0)
1706 		return (0);
1707 
1708 	bzero(&cmd, sizeof(cmd));
1709 	cmd.opcode = SPACE;
1710 	cmd.byte2 = what;
1711 	_lto3b(number, cmd.number);
1712 
1713 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1714 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1715 	    0, 0, 0, 900000, NULL, flags));
1716 }
1717 
1718 /*
1719  * write N filemarks
1720  */
1721 int
1722 st_write_filemarks(st, number, flags)
1723 	struct st_softc *st;
1724 	int flags;
1725 	int number;
1726 {
1727 	struct scsi_write_filemarks cmd;
1728 
1729 	/*
1730 	 * It's hard to write a negative number of file marks.
1731 	 * Don't try.
1732 	 */
1733 	if (number < 0)
1734 		return (EINVAL);
1735 	switch (number) {
1736 	case 0:		/* really a command to sync the drive's buffers */
1737 		break;
1738 	case 1:
1739 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1740 			st->flags &= ~ST_WRITTEN;
1741 		else
1742 			st->flags |= ST_FM_WRITTEN;
1743 		st->flags &= ~ST_PER_ACTION;
1744 		break;
1745 	default:
1746 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1747 	}
1748 
1749 	bzero(&cmd, sizeof(cmd));
1750 	cmd.opcode = WRITE_FILEMARKS;
1751 	_lto3b(number, cmd.number);
1752 
1753 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1754 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1755 	    0, 0, 0, 100000, NULL, flags));
1756 }
1757 
1758 /*
1759  * Make sure the right number of file marks is on tape if the
1760  * tape has been written.  If the position argument is true,
1761  * leave the tape positioned where it was originally.
1762  *
1763  * nmarks returns the number of marks to skip (or, if position
1764  * true, which were skipped) to get back original position.
1765  */
1766 int
1767 st_check_eod(st, position, nmarks, flags)
1768 	struct st_softc *st;
1769 	boolean position;
1770 	int *nmarks;
1771 	int flags;
1772 {
1773 	int error;
1774 
1775 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1776 	default:
1777 		*nmarks = 0;
1778 		return (0);
1779 	case ST_WRITTEN:
1780 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1781 		*nmarks = 1;
1782 		break;
1783 	case ST_WRITTEN | ST_2FM_AT_EOD:
1784 		*nmarks = 2;
1785 	}
1786 	error = st_write_filemarks(st, *nmarks, flags);
1787 	if (position && !error)
1788 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1789 	return (error);
1790 }
1791 
1792 /*
1793  * load/unload/retension
1794  */
1795 int
1796 st_load(st, type, flags)
1797 	struct st_softc *st;
1798 	u_int type;
1799 	int flags;
1800 {
1801 	struct scsi_load cmd;
1802 
1803 	if (type != LD_LOAD) {
1804 		int error;
1805 		int nmarks;
1806 
1807 		error = st_check_eod(st, FALSE, &nmarks, flags);
1808 		if (error)
1809 			return (error);
1810 	}
1811 	if (st->quirks & ST_Q_IGNORE_LOADS)
1812 		return (0);
1813 
1814 	bzero(&cmd, sizeof(cmd));
1815 	cmd.opcode = LOAD;
1816 	cmd.how = type;
1817 
1818 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1819 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1820 	    0, 0, ST_RETRIES, 300000, NULL, flags));
1821 }
1822 
1823 /*
1824  *  Rewind the device
1825  */
1826 int
1827 st_rewind(st, immediate, flags)
1828 	struct st_softc *st;
1829 	u_int immediate;
1830 	int flags;
1831 {
1832 	struct scsi_rewind cmd;
1833 	int error;
1834 	int nmarks;
1835 
1836 	error = st_check_eod(st, FALSE, &nmarks, flags);
1837 	if (error)
1838 		return (error);
1839 	st->flags &= ~ST_PER_ACTION;
1840 
1841 	bzero(&cmd, sizeof(cmd));
1842 	cmd.opcode = REWIND;
1843 	cmd.byte2 = immediate;
1844 
1845 	return ((*st->sc_link->scsipi_cmd)(st->sc_link,
1846 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1847 	    0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL, flags));
1848 }
1849 
1850 int
1851 st_rdpos(st, hard, blkptr)
1852 	struct st_softc *st;
1853 	int hard;
1854 	u_int32_t *blkptr;
1855 {
1856 	int error;
1857 	u_int8_t posdata[20];
1858 	struct scsi_tape_read_position cmd;
1859 
1860 	/*
1861 	 * First flush any pending writes...
1862 	 */
1863 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1864 
1865 	/*
1866 	 * The latter case is for 'write protected' tapes
1867 	 * which are too stupid to recognize a zero count
1868 	 * for writing filemarks as a no-op.
1869 	 */
1870 	if (error != 0 && error != EACCES)
1871 		return (error);
1872 
1873 	bzero(&cmd, sizeof(cmd));
1874 	bzero(&posdata, sizeof(posdata));
1875 	cmd.opcode = READ_POSITION;
1876 	if (hard)
1877 		cmd.byte1 = 1;
1878 
1879 	error = st->sc_link->scsipi_cmd(st->sc_link,
1880 	    (struct scsipi_generic *)&cmd, sizeof(cmd), (u_char *)&posdata,
1881 	    sizeof(posdata), ST_RETRIES, 30000, NULL, SCSI_DATA_IN);
1882 
1883 	if (error == 0) {
1884 #if	0
1885 		printf("posdata:");
1886 		for (hard = 0; hard < sizeof(posdata); hard++)
1887 			printf("%02x ", posdata[hard] & 0xff);
1888 		printf("\n");
1889 #endif
1890 		if (posdata[0] & 0x4)	/* Block Position Unknown */
1891 			error = EINVAL;
1892 		else {
1893 			*blkptr = _4btol(&posdata[4]);
1894 		}
1895 	}
1896 	return (error);
1897 }
1898 
1899 int
1900 st_setpos(st, hard, blkptr)
1901 	struct st_softc *st;
1902 	int hard;
1903 	u_int32_t *blkptr;
1904 {
1905 	int error;
1906 	struct scsipi_generic cmd;
1907 
1908 	/*
1909 	 * First flush any pending writes. Strictly speaking,
1910 	 * we're not supposed to have to worry about this,
1911 	 * but let's be untrusting.
1912 	 */
1913 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1914 
1915 	/*
1916 	 * The latter case is for 'write protected' tapes
1917 	 * which are too stupid to recognize a zero count
1918 	 * for writing filemarks as a no-op.
1919 	 */
1920 	if (error != 0 && error != EACCES)
1921 		return (error);
1922 
1923 	bzero(&cmd, sizeof(cmd));
1924 	cmd.opcode = LOCATE;
1925 	if (hard)
1926 		cmd.bytes[0] = 1 << 2;
1927 	_lto4b(*blkptr, &cmd.bytes[2]);
1928 	error = (*st->sc_link->scsipi_cmd)(st->sc_link, &cmd, sizeof(cmd),
1929 	    NULL, 0, ST_RETRIES, 5000, NULL, 0);
1930 	/*
1931 	 * XXX: Note file && block number position now unknown (if
1932 	 * XXX: these things ever start being maintained in this driver)
1933 	 */
1934 	return (error);
1935 }
1936 
1937 
1938 /*
1939  * Look at the returned sense and act on the error and detirmine
1940  * The unix error number to pass back... (0 = report no error)
1941  *                            (-1 = continue processing)
1942  */
1943 int
1944 st_interpret_sense(xs)
1945 	struct scsipi_xfer *xs;
1946 {
1947 	struct scsipi_link *sc_link = xs->sc_link;
1948 	struct scsipi_sense_data *sense = &xs->sense.scsi_sense;
1949 	struct buf *bp = xs->bp;
1950 	struct st_softc *st = sc_link->device_softc;
1951 	u_int8_t key;
1952 	int32_t info;
1953 
1954 	/*
1955 	 * Get the sense fields and work out what code
1956 	 */
1957 	if (sense->error_code & SSD_ERRCODE_VALID)
1958 		info = _4btol(sense->info);
1959 	else
1960 		info = xs->datalen;	/* bad choice if fixed blocks */
1961 	if ((sense->error_code & SSD_ERRCODE) != 0x70)
1962 		return (-1);		/* let the generic code handle it */
1963 #ifdef SCSIVERBOSE
1964 	else if ((xs->flags & SCSI_SILENT) == 0)
1965 		scsi_print_sense(xs, 0);    /* tell folks what happened */
1966 #endif
1967 	if (st->flags & ST_FIXEDBLOCKS) {
1968 		xs->resid = info * st->blksize;
1969 		if (sense->flags & SSD_EOM) {
1970 			st->flags |= ST_EIO_PENDING;
1971 			if (bp)
1972 				bp->b_resid = xs->resid;
1973 		}
1974 		if (sense->flags & SSD_FILEMARK) {
1975 			st->flags |= ST_AT_FILEMARK;
1976 			if (bp)
1977 				bp->b_resid = xs->resid;
1978 		}
1979 		if (sense->flags & SSD_ILI) {
1980 			st->flags |= ST_EIO_PENDING;
1981 			if (bp)
1982 				bp->b_resid = xs->resid;
1983 			if (sense->error_code & SSD_ERRCODE_VALID &&
1984 			    (xs->flags & SCSI_SILENT) == 0)
1985 				printf("%s: block wrong size, %d blocks residual\n",
1986 				    st->sc_dev.dv_xname, info);
1987 
1988 			/*
1989 			 * This quirk code helps the drive read
1990 			 * the first tape block, regardless of
1991 			 * format.  That is required for these
1992 			 * drives to return proper MODE SENSE
1993 			 * information.
1994 			 */
1995 			if ((st->quirks & ST_Q_SENSE_HELP) &&
1996 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
1997 				st->blksize -= 512;
1998 		}
1999 		/*
2000 		 * If no data was tranfered, do it immediatly
2001 		 */
2002 		if (xs->resid >= xs->datalen) {
2003 			if (st->flags & ST_EIO_PENDING)
2004 				return (EIO);
2005 			if (st->flags & ST_AT_FILEMARK) {
2006 				if (bp)
2007 					bp->b_resid = xs->resid;
2008 				return (0);
2009 			}
2010 		}
2011 	} else {		/* must be variable mode */
2012 		xs->resid = xs->datalen;	/* to be sure */
2013 		if (sense->flags & SSD_EOM)
2014 			return (EIO);
2015 		if (sense->flags & SSD_FILEMARK) {
2016 			if (bp)
2017 				bp->b_resid = bp->b_bcount;
2018 			return (0);
2019 		}
2020 		if (sense->flags & SSD_ILI) {
2021 			if (info < 0) {
2022 				/*
2023 				 * the record was bigger than the read
2024 				 */
2025 				if ((xs->flags & SCSI_SILENT) == 0)
2026 					printf("%s: %d-byte record too big\n",
2027 					    st->sc_dev.dv_xname,
2028 					    xs->datalen - info);
2029 				return (EIO);
2030 			}
2031 			xs->resid = info;
2032 			if (bp)
2033 				bp->b_resid = info;
2034 		}
2035 	}
2036 	key = sense->flags & SSD_KEY;
2037 
2038 	if (key == 0x8) {
2039 		/*
2040 		 * This quirk code helps the drive read the
2041 		 * first tape block, regardless of format.  That
2042 		 * is required for these drives to return proper
2043 		 * MODE SENSE information.
2044 		 */
2045 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2046 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
2047 			/* still starting */
2048 			st->blksize -= 512;
2049 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2050 			st->flags |= ST_BLANK_READ;
2051 			xs->resid = xs->datalen;
2052 			if (bp) {
2053 				bp->b_resid = xs->resid;
2054 				/* return an EOF */
2055 			}
2056 			return (0);
2057 		}
2058 	}
2059 	return (-1);		/* let the default/generic handler handle it */
2060 }
2061 
2062 /*
2063  * The quirk here is that the drive returns some value to st_mode_sense
2064  * incorrectly until the tape has actually passed by the head.
2065  *
2066  * The method is to set the drive to large fixed-block state (user-specified
2067  * density and 1024-byte blocks), then read and rewind to get it to sense the
2068  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2069  * work, as a last resort, try variable- length blocks.  The result will be
2070  * the ability to do an accurate st_mode_sense.
2071  *
2072  * We know we can do a rewind because we just did a load, which implies rewind.
2073  * Rewind seems preferable to space backward if we have a virgin tape.
2074  *
2075  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2076  * error processing, both part of st_interpret_sense.
2077  */
2078 int
2079 st_touch_tape(st)
2080 	struct st_softc *st;
2081 {
2082 	char *buf;
2083 	int readsize;
2084 	int error;
2085 
2086 	buf = malloc(1024, M_TEMP, M_NOWAIT);
2087 	if (buf == NULL)
2088 		return (ENOMEM);
2089 
2090 	if ((error = st_mode_sense(st, 0)) != 0)
2091 		goto bad;
2092 	st->blksize = 1024;
2093 	do {
2094 		switch (st->blksize) {
2095 		case 512:
2096 		case 1024:
2097 			readsize = st->blksize;
2098 			st->flags |= ST_FIXEDBLOCKS;
2099 			break;
2100 		default:
2101 			readsize = 1;
2102 			st->flags &= ~ST_FIXEDBLOCKS;
2103 		}
2104 		if ((error = st_mode_select(st, 0)) != 0)
2105 			goto bad;
2106 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
2107 		if ((error = st_rewind(st, 0, 0)) != 0) {
2108 bad:			free(buf, M_TEMP);
2109 			return (error);
2110 		}
2111 	} while (readsize != 1 && readsize > st->blksize);
2112 
2113 	free(buf, M_TEMP);
2114 	return (0);
2115 }
2116 
2117 int
2118 stdump(dev, blkno, va, size)
2119 	dev_t dev;
2120 	daddr_t blkno;
2121 	caddr_t va;
2122 	size_t size;
2123 {
2124 
2125 	/* Not implemented. */
2126 	return (ENXIO);
2127 }
2128