xref: /netbsd-src/sys/dev/scsipi/st.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: st.c,v 1.86 1997/12/28 19:25:35 is 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 #include "rnd.h"
58 
59 #include <sys/types.h>
60 #include <sys/param.h>
61 #include <sys/systm.h>
62 #include <sys/fcntl.h>
63 #include <sys/errno.h>
64 #include <sys/ioctl.h>
65 #include <sys/malloc.h>
66 #include <sys/buf.h>
67 #include <sys/proc.h>
68 #include <sys/user.h>
69 #include <sys/mtio.h>
70 #include <sys/device.h>
71 #include <sys/conf.h>
72 #if NRND > 0
73 #include <sys/rnd.h>
74 #endif
75 
76 #include <dev/scsipi/scsi_all.h>
77 #include <dev/scsipi/scsipi_all.h>
78 #include <dev/scsipi/scsi_all.h>
79 #include <dev/scsipi/scsi_tape.h>
80 #include <dev/scsipi/scsiconf.h>
81 
82 /* Defines for device specific stuff */
83 #define DEF_FIXED_BSIZE  512
84 #define	ST_RETRIES	4	/* only on non IO commands */
85 
86 #define STMODE(z)	( minor(z)       & 0x03)
87 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
88 #define STUNIT(z)	((minor(z) >> 4)       )
89 #define CTLMODE		3
90 
91 #define	FALSE		0
92 #define	TRUE		1
93 
94 /*
95  * Maximum density code known.
96  */
97 #define SCSI_2_MAX_DENSITY_CODE	0x45
98 
99 /*
100  * Define various devices that we know mis-behave in some way,
101  * and note how they are bad, so we can correct for them
102  */
103 struct modes {
104 	u_int quirks;			/* same definitions as in quirkdata */
105 	int blksize;
106 	u_int8_t density;
107 };
108 
109 struct quirkdata {
110 	u_int quirks;
111 #define	ST_Q_FORCE_BLKSIZE	0x0001
112 #define	ST_Q_SENSE_HELP		0x0002	/* must do READ for good MODE SENSE */
113 #define	ST_Q_IGNORE_LOADS	0x0004
114 #define	ST_Q_BLKSIZE		0x0008	/* variable-block media_blksize > 0 */
115 #define	ST_Q_UNIMODAL		0x0010	/* unimode drive rejects mode select */
116 	u_int page_0_size;
117 #define	MAX_PAGE_0_SIZE	64
118 	struct modes modes[4];
119 };
120 
121 struct st_quirk_inquiry_pattern {
122 	struct scsipi_inquiry_pattern pattern;
123 	struct quirkdata quirkdata;
124 };
125 
126 struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
127 	{{T_SEQUENTIAL, T_REMOV,
128 	 "        ", "                ", "    "}, {0, 0, {
129 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
130 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
131 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
132 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
133 	}}},
134 	{{T_SEQUENTIAL, T_REMOV,
135 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
136 		{0, 0, 0},				/* minor 0-3 */
137 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
138 		{0, 0, QIC_150},			/* minor 8-11 */
139 		{0, 0, QIC_120}				/* minor 12-15 */
140 	}}},
141  	{{T_SEQUENTIAL, T_REMOV,
142  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
143 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
144 		{0, 0, QIC_525},			/* minor 4-7 */
145 		{0, 0, QIC_150},			/* minor 8-11 */
146 		{0, 0, QIC_120}				/* minor 12-15 */
147 	}}},
148 	/*
149 	 * At least -005 and -007 need this.  I'll assume they all do unless I
150 	 * hear otherwise.  - mycroft, 31MAR1994
151 	 */
152 	{{T_SEQUENTIAL, T_REMOV,
153 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
154 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
155 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
156 		{0, 0, QIC_150},			/* minor 8-11 */
157 		{0, 0, QIC_120}				/* minor 12-15 */
158 	}}},
159 	/*
160 	 * One user reports that this works for his tape drive.  It probably
161 	 * needs more work.  - mycroft, 09APR1994
162 	 */
163 	{{T_SEQUENTIAL, T_REMOV,
164 	 "SANKYO  ", "CP525           ", ""},    {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 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
172 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
173 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
174 		{0, 0, QIC_150},			/* minor 8-11 */
175 		{0, 0, QIC_120}				/* minor 12-15 */
176 	}}},
177 	{{T_SEQUENTIAL, T_REMOV,
178 	 "ARCHIVE ", "VIPER 150  21247", ""},     {0, 12, {
179 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
180 		{0, 0, QIC_150},			/* minor 4-7 */
181 		{0, 0, QIC_120},			/* minor 8-11 */
182 		{0, 0, QIC_24}				/* minor 12-15 */
183 	}}},
184 	{{T_SEQUENTIAL, T_REMOV,
185 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
186 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
187 		{0, 0, QIC_11},				/* minor 4-7 */
188 		{0, 0, QIC_24},				/* minor 8-11 */
189 		{0, 0, QIC_24}				/* minor 12-15 */
190 	}}},
191 	{{T_SEQUENTIAL, T_REMOV,
192 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
193 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
194 		{0, 0, QIC_24},				/* minor 4-7 */
195 		{0, 0, QIC_120},			/* minor 8-11 */
196 		{0, 0, QIC_150}				/* minor 12-15 */
197 	}}},
198 	{{T_SEQUENTIAL, T_REMOV,
199 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
200 		{0, 0, 0},				/* minor 0-3 */
201 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
202 		{0, 0, QIC_150},			/* minor 8-11 */
203 		{0, 0, QIC_120}				/* minor 12-15 */
204 	}}},
205 	{{T_SEQUENTIAL, T_REMOV,
206 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
207 		{0, 0, 0},				/* minor 0-3 */
208 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
209 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
210 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
211 	}}},
212 	{{T_SEQUENTIAL, T_REMOV,
213 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
214 		{0, 0, 0},				/* minor 0-3 */
215 		{0, 0, 0},				/* minor 4-7 */
216 		{0, 0, 0},				/* minor 8-11 */
217 		{0, 0, 0}				/* minor 12-15 */
218 	}}},
219 	{{T_SEQUENTIAL, T_REMOV,
220 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
221 		{0, 0, 0},				/* minor 0-3 */
222 		{0, 0, 0},				/* minor 4-7 */
223 		{0, 0, 0},				/* minor 8-11 */
224 		{0, 0, 0}				/* minor 12-15 */
225 	}}},
226 	{{T_SEQUENTIAL, T_REMOV,
227 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
228 		{0, 0, QIC_3095},			/* minor 0-3 */
229 		{0, 0, QIC_3095},			/* minor 4-7 */
230 		{0, 0, QIC_3095},			/* minor 8-11 */
231 		{0, 0, QIC_3095},			/* minor 12-15 */
232 	}}},
233 #if 0
234 	{{T_SEQUENTIAL, T_REMOV,
235 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
236 		{0, 0, 0},				/* minor 0-3 */
237 		{0, 0, 0},				/* minor 4-7 */
238 		{0, 0, 0},				/* minor 8-11 */
239 		{0, 0, 0}				/* minor 12-15 */
240 	}}},
241 #endif
242 };
243 
244 #define NOEJECT 0
245 #define EJECT 1
246 
247 struct st_softc {
248 	struct device sc_dev;
249 /*--------------------present operating parameters, flags etc.---------------*/
250 	int flags;		/* see below                         */
251 	u_int quirks;		/* quirks for the open mode          */
252 	int blksize;		/* blksize we are using              */
253 	u_int8_t density;	/* present density                   */
254 	u_int page_0_size;	/* size of page 0 data		     */
255 	u_int last_dsty;	/* last density opened               */
256 /*--------------------device/scsi parameters---------------------------------*/
257 	struct scsipi_link *sc_link;	/* our link to the adpter etc.       */
258 /*--------------------parameters reported by the device ---------------------*/
259 	int blkmin;		/* min blk size                       */
260 	int blkmax;		/* max blk size                       */
261 	struct quirkdata *quirkdata;	/* if we have a rogue entry          */
262 /*--------------------parameters reported by the device for this media-------*/
263 	u_long numblks;		/* nominal blocks capacity            */
264 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
265 	u_int8_t media_density;	/* this is what it said when asked    */
266 /*--------------------quirks for the whole drive-----------------------------*/
267 	u_int drive_quirks;	/* quirks of this drive               */
268 /*--------------------How we should set up when opening each minor device----*/
269 	struct modes modes[4];	/* plus more for each mode            */
270 	u_int8_t  modeflags[4];	/* flags for the modes                */
271 #define DENSITY_SET_BY_USER	0x01
272 #define DENSITY_SET_BY_QUIRK	0x02
273 #define BLKSIZE_SET_BY_USER	0x04
274 #define BLKSIZE_SET_BY_QUIRK	0x08
275 /*--------------------storage for sense data returned by the drive-----------*/
276 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
277 						 * additional sense data needed
278 						 * for mode sense/select.
279 						 */
280 	struct buf buf_queue;		/* the queue of pending IO */
281 					/* operations */
282 #if NRND > 0
283 	rndsource_element_t	rnd_source;
284 #endif
285 };
286 
287 
288 #ifdef __BROKEN_INDIRECT_CONFIG
289 int	stmatch __P((struct device *, void *, void *));
290 #else
291 int	stmatch __P((struct device *, struct cfdata *, void *));
292 #endif
293 void	stattach __P((struct device *, struct device *, void *));
294 void	st_identify_drive __P((struct st_softc *,
295 	    struct scsipi_inquiry_pattern *));
296 void	st_loadquirks __P((struct st_softc *));
297 int	st_mount_tape __P((dev_t, int));
298 void	st_unmount __P((struct st_softc *, boolean));
299 int	st_decide_mode __P((struct st_softc *, boolean));
300 void	ststart __P((void *));
301 void	stdone __P((struct scsipi_xfer *));
302 int	st_read __P((struct st_softc *, char *, int, int));
303 int	st_read_block_limits __P((struct st_softc *, int));
304 int	st_mode_sense __P((struct st_softc *, int));
305 int	st_mode_select __P((struct st_softc *, int));
306 int	st_cmprss __P((struct st_softc *, int));
307 int	st_space __P((struct st_softc *, int, u_int, int));
308 int	st_write_filemarks __P((struct st_softc *, int, int));
309 int	st_check_eod __P((struct st_softc *, boolean, int *, int));
310 int	st_load __P((struct st_softc *, u_int, int));
311 int	st_rewind __P((struct st_softc *, u_int, int));
312 int	st_interpret_sense __P((struct scsipi_xfer *));
313 int	st_touch_tape __P((struct st_softc *));
314 int	st_erase __P((struct st_softc *, int full, int flags));
315 int	st_rdpos __P((struct st_softc *, int, u_int32_t *));
316 int	st_setpos __P((struct st_softc *, int, u_int32_t *));
317 
318 struct cfattach st_ca = {
319 	sizeof(struct st_softc), stmatch, stattach
320 };
321 
322 struct cfdriver st_cd = {
323 	NULL, "st", DV_TAPE
324 };
325 
326 struct scsipi_device st_switch = {
327 	st_interpret_sense,
328 	ststart,
329 	NULL,
330 #if NRND > 0
331 	stdone,  /* only needed to gather timing data for randomness */
332 #else
333 	NULL,
334 #endif
335 };
336 
337 #define	ST_INFO_VALID	0x0001
338 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
339 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
340 #define	ST_FIXEDBLOCKS	0x0008
341 #define	ST_AT_FILEMARK	0x0010
342 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
343 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode             */
344 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
345 #define	ST_FM_WRITTEN	0x0100	/*
346 				 * EOF file mark written  -- used with
347 				 * ~ST_WRITTEN to indicate that multiple file
348 				 * marks have been written
349 				 */
350 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
351 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
352 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
353 #define	ST_DONTBUFFER	0x1000	/* Disable buffering/caching */
354 
355 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
356 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN |	\
357 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN |	\
358 			 ST_2FM_AT_EOD | ST_PER_ACTION)
359 
360 struct scsipi_inquiry_pattern st_patterns[] = {
361 	{T_SEQUENTIAL, T_REMOV,
362 	 "",         "",                 ""},
363 };
364 
365 int
366 stmatch(parent, match, aux)
367 	struct device *parent;
368 #ifdef __BROKEN_INDIRECT_CONFIG
369 	void *match;
370 #else
371 	struct cfdata *match;
372 #endif
373 	void *aux;
374 {
375 	struct scsipibus_attach_args *sa = aux;
376 	int priority;
377 
378 	(void)scsipi_inqmatch(&sa->sa_inqbuf,
379 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
380 	    sizeof(st_patterns[0]), &priority);
381 	return (priority);
382 }
383 
384 /*
385  * The routine called by the low level scsi routine when it discovers
386  * A device suitable for this driver
387  */
388 void
389 stattach(parent, self, aux)
390 	struct device *parent, *self;
391 	void *aux;
392 {
393 	struct st_softc *st = (void *)self;
394 	struct scsipibus_attach_args *sa = aux;
395 	struct scsipi_link *sc_link = sa->sa_sc_link;
396 
397 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
398 
399 	/*
400 	 * Store information needed to contact our base driver
401 	 */
402 	st->sc_link = sc_link;
403 	sc_link->device = &st_switch;
404 	sc_link->device_softc = st;
405 	sc_link->openings = 1;
406 
407 	/*
408 	 * Check if the drive is a known criminal and take
409 	 * Any steps needed to bring it into line
410 	 */
411 	st_identify_drive(st, &sa->sa_inqbuf);
412 
413 	/*
414 	 * Use the subdriver to request information regarding
415 	 * the drive. We cannot use interrupts yet, so the
416 	 * request must specify this.
417 	 */
418 	printf("\n");
419 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
420 	if (scsipi_test_unit_ready(sc_link,
421 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
422 	    st_mode_sense(st,
423 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
424 		printf("drive empty\n");
425 	else {
426 		printf("density code 0x%x, ", st->media_density);
427 		if (st->media_blksize > 0)
428 			printf("%d-byte", st->media_blksize);
429 		else
430 			printf("variable");
431 		printf(" blocks, write-%s\n",
432 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
433 	}
434 
435 	/*
436 	 * Set up the buf queue for this device
437 	 */
438 	st->buf_queue.b_active = 0;
439 	st->buf_queue.b_actf = 0;
440 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
441 
442 #if NRND > 0
443 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname, RND_TYPE_TAPE);
444 #endif
445 }
446 
447 /*
448  * Use the inquiry routine in 'scsi_base' to get drive info so we can
449  * Further tailor our behaviour.
450  */
451 void
452 st_identify_drive(st, inqbuf)
453 	struct st_softc *st;
454 	struct scsipi_inquiry_pattern *inqbuf;
455 {
456 	struct st_quirk_inquiry_pattern *finger;
457 	int priority;
458 
459 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
460 	    (caddr_t)st_quirk_patterns,
461 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
462 	    sizeof(st_quirk_patterns[0]), &priority);
463 	if (priority != 0) {
464 		st->quirkdata = &finger->quirkdata;
465 		st->drive_quirks = finger->quirkdata.quirks;
466 		st->quirks = finger->quirkdata.quirks;	/* start value */
467 		st->page_0_size = finger->quirkdata.page_0_size;
468 		st_loadquirks(st);
469 	}
470 }
471 
472 /*
473  * initialise the subdevices to the default (QUIRK) state.
474  * this will remove any setting made by the system operator or previous
475  * operations.
476  */
477 void
478 st_loadquirks(st)
479 	struct st_softc *st;
480 {
481 	int i;
482 	struct	modes *mode;
483 	struct	modes *mode2;
484 
485 	mode = st->quirkdata->modes;
486 	mode2 = st->modes;
487 	for (i = 0; i < 4; i++) {
488 		bzero(mode2, sizeof(struct modes));
489 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
490 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
491 		    DENSITY_SET_BY_USER);
492 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
493 			mode2->blksize = mode->blksize;
494 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
495 		}
496 		if (mode->density) {
497 			mode2->density = mode->density;
498 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
499 		}
500 		mode++;
501 		mode2++;
502 	}
503 }
504 
505 /*
506  * open the device.
507  */
508 int
509 stopen(dev, flags, mode, p)
510 	dev_t dev;
511 	int flags;
512 	int mode;
513 	struct proc *p;
514 {
515 	int unit;
516 	u_int stmode, dsty;
517 	int error = 0;
518 	struct st_softc *st;
519 	struct scsipi_link *sc_link;
520 
521 	unit = STUNIT(dev);
522 	if (unit >= st_cd.cd_ndevs)
523 		return (ENXIO);
524 	st = st_cd.cd_devs[unit];
525 	if (st == NULL)
526 		return (ENXIO);
527 
528 	stmode = STMODE(dev);
529 	dsty = STDSTY(dev);
530 	sc_link = st->sc_link;
531 
532 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
533 	    unit, st_cd.cd_ndevs));
534 
535 	/*
536 	 * Only allow one at a time
537 	 */
538 	if (sc_link->flags & SDEV_OPEN) {
539 		printf("%s: already open\n", st->sc_dev.dv_xname);
540 		return (EBUSY);
541 	}
542 
543 	/*
544 	 * Catch any unit attention errors.
545 	 */
546 	error = scsipi_test_unit_ready(sc_link, SCSI_IGNORE_MEDIA_CHANGE |
547 	    (stmode == CTLMODE ? SCSI_IGNORE_NOT_READY : 0));
548 	if (error)
549 		goto bad;
550 
551 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
552 
553 	/*
554 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
555 	 * then the device has been opened to set defaults
556 	 * This mode does NOT ALLOW I/O, only ioctls
557 	 */
558 	if (stmode == CTLMODE)
559 		return (0);
560 
561 	/*
562 	 * if it's a different mode, or if the media has been
563 	 * invalidated, unmount the tape from the previous
564 	 * session but continue with open processing
565 	 */
566 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
567 		st_unmount(st, NOEJECT);
568 
569 	/*
570 	 * If we are not mounted, then we should start a new
571 	 * mount session.
572 	 */
573 	if (!(st->flags & ST_MOUNTED)) {
574 		st_mount_tape(dev, flags);
575 		st->last_dsty = dsty;
576 	}
577 
578 	/*
579 	 * Make sure that a tape opened in write-only mode will have
580 	 * file marks written on it when closed, even if not written to.
581 	 * This is for SUN compatibility
582 	 */
583 	if ((flags & O_ACCMODE) == FWRITE)
584 		st->flags |= ST_WRITTEN;
585 
586 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
587 	return (0);
588 
589 bad:
590 	st_unmount(st, NOEJECT);
591 	sc_link->flags &= ~SDEV_OPEN;
592 	return (error);
593 }
594 
595 /*
596  * close the device.. only called if we are the LAST
597  * occurence of an open device
598  */
599 int
600 stclose(dev, flags, mode, p)
601 	dev_t dev;
602 	int flags;
603 	int mode;
604 	struct proc *p;
605 {
606 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
607 
608 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
609 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
610 		st_write_filemarks(st, 1, 0);
611 	switch (STMODE(dev)) {
612 	case 0:
613 	case 3:		/* for now */
614 		st_unmount(st, NOEJECT);
615 		break;
616 	case 1:
617 		/* leave mounted unless media seems to have been removed */
618 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
619 			st_unmount(st, NOEJECT);
620 		break;
621 	case 2:
622 		st_unmount(st, EJECT);
623 		break;
624 	}
625 	st->sc_link->flags &= ~SDEV_OPEN;
626 
627 	return (0);
628 }
629 
630 /*
631  * Start a new mount session.
632  * Copy in all the default parameters from the selected device mode.
633  * and try guess any that seem to be defaulted.
634  */
635 int
636 st_mount_tape(dev, flags)
637 	dev_t dev;
638 	int flags;
639 {
640 	int unit;
641 	u_int mode, dsty;
642 	struct st_softc *st;
643 	struct scsipi_link *sc_link;
644 	int error = 0;
645 
646 	unit = STUNIT(dev);
647 	mode = STMODE(dev);
648 	dsty = STDSTY(dev);
649 	st = st_cd.cd_devs[unit];
650 	sc_link = st->sc_link;
651 
652 	if (st->flags & ST_MOUNTED)
653 		return (0);
654 
655 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
656 	st->flags |= ST_NEW_MOUNT;
657 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
658 	/*
659 	 * If the media is new, then make sure we give it a chance to
660 	 * to do a 'load' instruction.  (We assume it is new.)
661 	 */
662 	if ((error = st_load(st, LD_LOAD, 0)) != 0)
663 		return (error);
664 	/*
665 	 * Throw another dummy instruction to catch
666 	 * 'Unit attention' errors. Some drives appear to give
667 	 * these after doing a Load instruction.
668 	 * (noteably some DAT drives)
669 	 */
670 	scsipi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
671 
672 	/*
673 	 * Some devices can't tell you much until they have been
674 	 * asked to look at the media. This quirk does this.
675 	 */
676 	if (st->quirks & ST_Q_SENSE_HELP)
677 		if ((error = st_touch_tape(st)) != 0)
678 			return (error);
679 	/*
680 	 * Load the physical device parameters
681 	 * loads: blkmin, blkmax
682 	 */
683 	if ((error = st_read_block_limits(st, 0)) != 0)
684 		return (error);
685 	/*
686 	 * Load the media dependent parameters
687 	 * includes: media_blksize,media_density,numblks
688 	 * As we have a tape in, it should be reflected here.
689 	 * If not you may need the "quirk" above.
690 	 */
691 	if ((error = st_mode_sense(st, 0)) != 0)
692 		return (error);
693 	/*
694 	 * If we have gained a permanent density from somewhere,
695 	 * then use it in preference to the one supplied by
696 	 * default by the driver.
697 	 */
698 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
699 		st->density = st->modes[dsty].density;
700 	else
701 		st->density = st->media_density;
702 	/*
703 	 * If we have gained a permanent blocksize
704 	 * then use it in preference to the one supplied by
705 	 * default by the driver.
706 	 */
707 	st->flags &= ~ST_FIXEDBLOCKS;
708 	if (st->modeflags[dsty] &
709 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
710 		st->blksize = st->modes[dsty].blksize;
711 		if (st->blksize)
712 			st->flags |= ST_FIXEDBLOCKS;
713 	} else {
714 		if ((error = st_decide_mode(st, FALSE)) != 0)
715 			return (error);
716 	}
717 	if ((error = st_mode_select(st, 0)) != 0) {
718 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
719 		return (error);
720 	}
721 	scsipi_prevent(sc_link, PR_PREVENT,
722 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
723 	st->flags &= ~ST_NEW_MOUNT;
724 	st->flags |= ST_MOUNTED;
725 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
726 
727 	return (0);
728 }
729 
730 /*
731  * End the present mount session.
732  * Rewind, and optionally eject the tape.
733  * Reset various flags to indicate that all new
734  * operations require another mount operation
735  */
736 void
737 st_unmount(st, eject)
738 	struct st_softc *st;
739 	boolean eject;
740 {
741 	struct scsipi_link *sc_link = st->sc_link;
742 	int nmarks;
743 
744 	if (!(st->flags & ST_MOUNTED))
745 		return;
746 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
747 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
748 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
749 	scsipi_prevent(sc_link, PR_ALLOW,
750 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
751 	if (eject)
752 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
753 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
754 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
755 }
756 
757 /*
758  * Given all we know about the device, media, mode, 'quirks' and
759  * initial operation, make a decision as to how we should be set
760  * to run (regarding blocking and EOD marks)
761  */
762 int
763 st_decide_mode(st, first_read)
764 	struct st_softc *st;
765 	boolean	first_read;
766 {
767 #ifdef SCSIDEBUG
768 	struct scsipi_link *sc_link = st->sc_link;
769 #endif
770 
771 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
772 
773 	/*
774 	 * If the drive can only handle fixed-length blocks and only at
775 	 * one size, perhaps we should just do that.
776 	 */
777 	if (st->blkmin && (st->blkmin == st->blkmax)) {
778 		st->flags |= ST_FIXEDBLOCKS;
779 		st->blksize = st->blkmin;
780 		SC_DEBUG(sc_link, SDEV_DB3,
781 		    ("blkmin == blkmax of %d\n", st->blkmin));
782 		goto done;
783 	}
784 	/*
785 	 * If the tape density mandates (or even suggests) use of fixed
786 	 * or variable-length blocks, comply.
787 	 */
788 	switch (st->density) {
789 	case HALFINCH_800:
790 	case HALFINCH_1600:
791 	case HALFINCH_6250:
792 	case DDS:
793 		st->flags &= ~ST_FIXEDBLOCKS;
794 		st->blksize = 0;
795 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
796 		goto done;
797 	case QIC_11:
798 	case QIC_24:
799 	case QIC_120:
800 	case QIC_150:
801 	case QIC_525:
802 	case QIC_1320:
803 		st->flags |= ST_FIXEDBLOCKS;
804 		if (st->media_blksize > 0)
805 			st->blksize = st->media_blksize;
806 		else
807 			st->blksize = DEF_FIXED_BSIZE;
808 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
809 		goto done;
810 	}
811 	/*
812 	 * If we're about to read the tape, perhaps we should choose
813 	 * fixed or variable-length blocks and block size according to
814 	 * what the drive found on the tape.
815 	 */
816 	if (first_read &&
817 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
818 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
819 	    (st->media_blksize == 1024))) {
820 		if (st->media_blksize > 0)
821 			st->flags |= ST_FIXEDBLOCKS;
822 		else
823 			st->flags &= ~ST_FIXEDBLOCKS;
824 		st->blksize = st->media_blksize;
825 		SC_DEBUG(sc_link, SDEV_DB3,
826 		    ("Used media_blksize of %d\n", st->media_blksize));
827 		goto done;
828 	}
829 	/*
830 	 * We're getting no hints from any direction.  Choose variable-
831 	 * length blocks arbitrarily.
832 	 */
833 	st->flags &= ~ST_FIXEDBLOCKS;
834 	st->blksize = 0;
835 	SC_DEBUG(sc_link, SDEV_DB3,
836 	    ("Give up and default to variable mode\n"));
837 
838 done:
839 	/*
840 	 * Decide whether or not to write two file marks to signify end-
841 	 * of-data.  Make the decision as a function of density.  If
842 	 * the decision is not to use a second file mark, the SCSI BLANK
843 	 * CHECK condition code will be recognized as end-of-data when
844 	 * first read.
845 	 * (I think this should be a by-product of fixed/variable..julian)
846 	 */
847 	switch (st->density) {
848 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
849 	case QIC_11:
850 	case QIC_24:
851 	case QIC_120:
852 	case QIC_150:
853 	case QIC_525:
854 	case QIC_1320:
855 		st->flags &= ~ST_2FM_AT_EOD;
856 		break;
857 	default:
858 		st->flags |= ST_2FM_AT_EOD;
859 	}
860 	return (0);
861 }
862 
863 /*
864  * Actually translate the requested transfer into
865  * one the physical driver can understand
866  * The transfer is described by a buf and will include
867  * only one physical transfer.
868  */
869 void
870 ststrategy(bp)
871 	struct buf *bp;
872 {
873 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
874 	struct buf *dp;
875 	int s;
876 
877 	SC_DEBUG(st->sc_link, SDEV_DB1,
878 	    ("ststrategy %ld bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
879 	/*
880 	 * If it's a null transfer, return immediatly
881 	 */
882 	if (bp->b_bcount == 0)
883 		goto done;
884 	/*
885 	 * Odd sized request on fixed drives are verboten
886 	 */
887 	if (st->flags & ST_FIXEDBLOCKS) {
888 		if (bp->b_bcount % st->blksize) {
889 			printf("%s: bad request, must be multiple of %d\n",
890 			    st->sc_dev.dv_xname, st->blksize);
891 			bp->b_error = EIO;
892 			goto bad;
893 		}
894 	}
895 	/*
896 	 * as are out-of-range requests on variable drives.
897 	 */
898 	else if (bp->b_bcount < st->blkmin ||
899 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
900 		printf("%s: bad request, must be between %d and %d\n",
901 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
902 		bp->b_error = EIO;
903 		goto bad;
904 	}
905 	s = splbio();
906 
907 	/*
908 	 * Place it in the queue of activities for this tape
909 	 * at the end (a bit silly because we only have on user..
910 	 * (but it could fork()))
911 	 */
912 	dp = &st->buf_queue;
913 	bp->b_actf = NULL;
914 	bp->b_actb = dp->b_actb;
915 	*dp->b_actb = bp;
916 	dp->b_actb = &bp->b_actf;
917 
918 	/*
919 	 * Tell the device to get going on the transfer if it's
920 	 * not doing anything, otherwise just wait for completion
921 	 * (All a bit silly if we're only allowing 1 open but..)
922 	 */
923 	ststart(st);
924 
925 	splx(s);
926 	return;
927 bad:
928 	bp->b_flags |= B_ERROR;
929 done:
930 	/*
931 	 * Correctly set the buf to indicate a completed xfer
932 	 */
933 	bp->b_resid = bp->b_bcount;
934 	biodone(bp);
935 	return;
936 }
937 
938 /*
939  * ststart looks to see if there is a buf waiting for the device
940  * and that the device is not already busy. If both are true,
941  * It dequeues the buf and creates a scsi command to perform the
942  * transfer required. The transfer request will call scsipi_done
943  * on completion, which will in turn call this routine again
944  * so that the next queued transfer is performed.
945  * The bufs are queued by the strategy routine (ststrategy)
946  *
947  * This routine is also called after other non-queued requests
948  * have been made of the scsi driver, to ensure that the queue
949  * continues to be drained.
950  * ststart() is called at splbio
951  */
952 void
953 ststart(v)
954 	void *v;
955 {
956 	struct st_softc *st = v;
957 	struct scsipi_link *sc_link = st->sc_link;
958 	register struct buf *bp, *dp;
959 	struct scsi_rw_tape cmd;
960 	int flags;
961 
962 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
963 	/*
964 	 * See if there is a buf to do and we are not already
965 	 * doing one
966 	 */
967 	while (sc_link->openings > 0) {
968 		/* if a special awaits, let it proceed first */
969 		if (sc_link->flags & SDEV_WAITING) {
970 			sc_link->flags &= ~SDEV_WAITING;
971 			wakeup((caddr_t)sc_link);
972 			return;
973 		}
974 
975 		dp = &st->buf_queue;
976 		if ((bp = dp->b_actf) == NULL)
977 			return;
978 		if ((dp = bp->b_actf) != NULL)
979 			dp->b_actb = bp->b_actb;
980 		else
981 			st->buf_queue.b_actb = bp->b_actb;
982 		*bp->b_actb = dp;
983 
984 		/*
985 		 * if the device has been unmounted byt the user
986 		 * then throw away all requests until done
987 		 */
988 		if (!(st->flags & ST_MOUNTED) ||
989 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
990 			/* make sure that one implies the other.. */
991 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
992 			bp->b_flags |= B_ERROR;
993 			bp->b_error = EIO;
994 			bp->b_resid = bp->b_bcount;
995 			biodone(bp);
996 			continue;
997 		}
998 		/*
999 		 * only FIXEDBLOCK devices have pending operations
1000 		 */
1001 		if (st->flags & ST_FIXEDBLOCKS) {
1002 			/*
1003 			 * If we are at a filemark but have not reported it yet
1004 			 * then we should report it now
1005 			 */
1006 			if (st->flags & ST_AT_FILEMARK) {
1007 				if ((bp->b_flags & B_READ) == B_WRITE) {
1008 					/*
1009 					 * Handling of ST_AT_FILEMARK in
1010 					 * st_space will fill in the right file
1011 					 * mark count.
1012 					 * Back up over filemark
1013 					 */
1014 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1015 						bp->b_flags |= B_ERROR;
1016 						bp->b_error = EIO;
1017 						biodone(bp);
1018 						continue;
1019 					}
1020 				} else {
1021 					bp->b_resid = bp->b_bcount;
1022 					bp->b_error = 0;
1023 					bp->b_flags &= ~B_ERROR;
1024 					st->flags &= ~ST_AT_FILEMARK;
1025 					biodone(bp);
1026 					continue;	/* seek more work */
1027 				}
1028 			}
1029 			/*
1030 			 * If we are at EIO (e.g. EOM) but have not reported it
1031 			 * yet then we should report it now
1032 			 */
1033 			if (st->flags & ST_EIO_PENDING) {
1034 				bp->b_resid = bp->b_bcount;
1035 				bp->b_error = EIO;
1036 				bp->b_flags |= B_ERROR;
1037 				st->flags &= ~ST_EIO_PENDING;
1038 				biodone(bp);
1039 				continue;	/* seek more work */
1040 			}
1041 		}
1042 
1043 		/*
1044 		 *  Fill out the scsi command
1045 		 */
1046 		bzero(&cmd, sizeof(cmd));
1047 		if ((bp->b_flags & B_READ) == B_WRITE) {
1048 			cmd.opcode = WRITE;
1049 			st->flags &= ~ST_FM_WRITTEN;
1050 			st->flags |= ST_WRITTEN;
1051 			flags = SCSI_DATA_OUT;
1052 		} else {
1053 			cmd.opcode = READ;
1054 			flags = SCSI_DATA_IN;
1055 		}
1056 
1057 		/*
1058 		 * Handle "fixed-block-mode" tape drives by using the
1059 		 * block count instead of the length.
1060 		 */
1061 		if (st->flags & ST_FIXEDBLOCKS) {
1062 			cmd.byte2 |= SRW_FIXED;
1063 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1064 		} else
1065 			_lto3b(bp->b_bcount, cmd.len);
1066 
1067 		/*
1068 		 * go ask the adapter to do all this for us
1069 		 */
1070 		if (scsipi_command(sc_link,
1071 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1072 		    (u_char *)bp->b_data, bp->b_bcount,
1073 		    0, 100000, bp, flags | SCSI_NOSLEEP))
1074 			printf("%s: not queued\n", st->sc_dev.dv_xname);
1075 	} /* go back and see if we can cram more work in.. */
1076 }
1077 
1078 #if NRND > 0
1079 void
1080 stdone(xs)
1081 	struct scsipi_xfer *xs;
1082 {
1083 	struct st_softc *st = xs->sc_link->device_softc;
1084 
1085 	if (xs->bp != NULL)
1086 		rnd_add_uint32(&st->rnd_source, xs->bp->b_blkno);
1087 }
1088 #endif
1089 
1090 int
1091 stread(dev, uio, iomode)
1092 	dev_t dev;
1093 	struct uio *uio;
1094 	int iomode;
1095 {
1096 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1097 
1098 	return (physio(ststrategy, NULL, dev, B_READ,
1099 	    st->sc_link->adapter->scsipi_minphys, uio));
1100 }
1101 
1102 int
1103 stwrite(dev, uio, iomode)
1104 	dev_t dev;
1105 	struct uio *uio;
1106 	int iomode;
1107 {
1108 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1109 
1110 	return (physio(ststrategy, NULL, dev, B_WRITE,
1111 	    st->sc_link->adapter->scsipi_minphys, uio));
1112 }
1113 
1114 /*
1115  * Perform special action on behalf of the user;
1116  * knows about the internals of this device
1117  */
1118 int
1119 stioctl(dev, cmd, arg, flag, p)
1120 	dev_t dev;
1121 	u_long cmd;
1122 	caddr_t arg;
1123 	int flag;
1124 	struct proc *p;
1125 {
1126 	int error = 0;
1127 	int unit;
1128 	int number, nmarks, dsty;
1129 	int flags;
1130 	struct st_softc *st;
1131 	int hold_blksize;
1132 	u_int8_t hold_density;
1133 	struct mtop *mt = (struct mtop *) arg;
1134 
1135 	/*
1136 	 * Find the device that the user is talking about
1137 	 */
1138 	flags = 0;		/* give error messages, act on errors etc. */
1139 	unit = STUNIT(dev);
1140 	dsty = STDSTY(dev);
1141 	st = st_cd.cd_devs[unit];
1142 	hold_blksize = st->blksize;
1143 	hold_density = st->density;
1144 
1145 	switch ((u_int) cmd) {
1146 
1147 	case MTIOCGET: {
1148 		struct mtget *g = (struct mtget *) arg;
1149 
1150 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1151 		bzero(g, sizeof(struct mtget));
1152 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1153 		g->mt_blksiz = st->blksize;
1154 		g->mt_density = st->density;
1155 		g->mt_mblksiz[0] = st->modes[0].blksize;
1156 		g->mt_mblksiz[1] = st->modes[1].blksize;
1157 		g->mt_mblksiz[2] = st->modes[2].blksize;
1158 		g->mt_mblksiz[3] = st->modes[3].blksize;
1159 		g->mt_mdensity[0] = st->modes[0].density;
1160 		g->mt_mdensity[1] = st->modes[1].density;
1161 		g->mt_mdensity[2] = st->modes[2].density;
1162 		g->mt_mdensity[3] = st->modes[3].density;
1163 		break;
1164 	}
1165 	case MTIOCTOP: {
1166 
1167 		SC_DEBUG(st->sc_link, SDEV_DB1,
1168 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1169 			mt->mt_count));
1170 
1171 		/* compat: in U*x it is a short */
1172 		number = mt->mt_count;
1173 		switch ((short) (mt->mt_op)) {
1174 		case MTWEOF:	/* write an end-of-file record */
1175 			error = st_write_filemarks(st, number, flags);
1176 			break;
1177 		case MTBSF:	/* backward space file */
1178 			number = -number;
1179 		case MTFSF:	/* forward space file */
1180 			error = st_check_eod(st, FALSE, &nmarks, flags);
1181 			if (!error)
1182 				error = st_space(st, number - nmarks,
1183 				    SP_FILEMARKS, flags);
1184 			break;
1185 		case MTBSR:	/* backward space record */
1186 			number = -number;
1187 		case MTFSR:	/* forward space record */
1188 			error = st_check_eod(st, TRUE, &nmarks, flags);
1189 			if (!error)
1190 				error = st_space(st, number, SP_BLKS, flags);
1191 			break;
1192 		case MTREW:	/* rewind */
1193 			error = st_rewind(st, 0, flags);
1194 			break;
1195 		case MTOFFL:	/* rewind and put the drive offline */
1196 			st_unmount(st, EJECT);
1197 			break;
1198 		case MTNOP:	/* no operation, sets status only */
1199 			break;
1200 		case MTRETEN:	/* retension the tape */
1201 			error = st_load(st, LD_RETENSION, flags);
1202 			if (!error)
1203 				error = st_load(st, LD_LOAD, flags);
1204 			break;
1205 		case MTEOM:	/* forward space to end of media */
1206 			error = st_check_eod(st, FALSE, &nmarks, flags);
1207 			if (!error)
1208 				error = st_space(st, 1, SP_EOM, flags);
1209 			break;
1210 		case MTCACHE:	/* enable controller cache */
1211 			st->flags &= ~ST_DONTBUFFER;
1212 			goto try_new_value;
1213 		case MTNOCACHE:	/* disable controller cache */
1214 			st->flags |= ST_DONTBUFFER;
1215 			goto try_new_value;
1216 		case MTERASE:	/* erase volume */
1217 			error = st_erase(st, number, flags);
1218 			break;
1219 		case MTSETBSIZ:	/* Set block size for device */
1220 #ifdef	NOTYET
1221 			if (!(st->flags & ST_NEW_MOUNT)) {
1222 				uprintf("re-mount tape before changing blocksize");
1223 				error = EINVAL;
1224 				break;
1225 			}
1226 #endif
1227 			if (number == 0)
1228 				st->flags &= ~ST_FIXEDBLOCKS;
1229 			else {
1230 				if ((st->blkmin || st->blkmax) &&
1231 				    (number < st->blkmin ||
1232 				    number > st->blkmax)) {
1233 					error = EINVAL;
1234 					break;
1235 				}
1236 				st->flags |= ST_FIXEDBLOCKS;
1237 			}
1238 			st->blksize = number;
1239 			st->flags |= ST_BLOCK_SET;	/*XXX */
1240 			goto try_new_value;
1241 
1242 		case MTSETDNSTY:	/* Set density for device and mode */
1243 			if (number > SCSI_2_MAX_DENSITY_CODE) {
1244 				error = EINVAL;
1245 				break;
1246 			} else
1247 				st->density = number;
1248 			goto try_new_value;
1249 
1250 		case MTCMPRESS:
1251 			error = st_cmprss(st, number);
1252 			break;
1253 
1254 		default:
1255 			error = EINVAL;
1256 		}
1257 		break;
1258 	}
1259 	case MTIOCIEOT:
1260 	case MTIOCEEOT:
1261 		break;
1262 
1263 	case MTIOCRDSPOS:
1264 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1265 		break;
1266 
1267 	case MTIOCRDHPOS:
1268 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1269 		break;
1270 
1271 	case MTIOCSLOCATE:
1272 		error = st_setpos(st, 0, (u_int32_t *) arg);
1273 		break;
1274 
1275 	case MTIOCHLOCATE:
1276 		error = st_setpos(st, 1, (u_int32_t *) arg);
1277 		break;
1278 
1279 	default:
1280 		if (STMODE(dev) == CTLMODE)
1281 			error = scsipi_do_ioctl(st->sc_link, dev, cmd, arg,
1282 			    flag, p);
1283 		else
1284 			error = ENOTTY;
1285 		break;
1286 	}
1287 	return (error);
1288 /*-----------------------------*/
1289 try_new_value:
1290 	/*
1291 	 * Check that the mode being asked for is aggreeable to the
1292 	 * drive. If not, put it back the way it was.
1293 	 */
1294 	if ((error = st_mode_select(st, 0)) != 0) {/* put it back as it was */
1295 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1296 		st->density = hold_density;
1297 		st->blksize = hold_blksize;
1298 		if (st->blksize)
1299 			st->flags |= ST_FIXEDBLOCKS;
1300 		else
1301 			st->flags &= ~ST_FIXEDBLOCKS;
1302 		return (error);
1303 	}
1304 	/*
1305 	 * As the drive liked it, if we are setting a new default,
1306 	 * set it into the structures as such.
1307 	 *
1308 	 * The means for deciding this are not finalised yet
1309 	 */
1310 	if (STMODE(dev) == 0x03) {
1311 		/* special mode */
1312 		/* XXX */
1313 		switch ((short) (mt->mt_op)) {
1314 		case MTSETBSIZ:
1315 			st->modes[dsty].blksize = st->blksize;
1316 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1317 			break;
1318 		case MTSETDNSTY:
1319 			st->modes[dsty].density = st->density;
1320 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1321 			break;
1322 		}
1323 	}
1324 	return (0);
1325 }
1326 
1327 /*
1328  * Do a synchronous read.
1329  */
1330 int
1331 st_read(st, buf, size, flags)
1332 	struct st_softc *st;
1333 	int size;
1334 	int flags;
1335 	char *buf;
1336 {
1337 	struct scsi_rw_tape cmd;
1338 
1339 	/*
1340 	 * If it's a null transfer, return immediatly
1341 	 */
1342 	if (size == 0)
1343 		return (0);
1344 	bzero(&cmd, sizeof(cmd));
1345 	cmd.opcode = READ;
1346 	if (st->flags & ST_FIXEDBLOCKS) {
1347 		cmd.byte2 |= SRW_FIXED;
1348 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1349 		    cmd.len);
1350 	} else
1351 		_lto3b(size, cmd.len);
1352 	return (scsipi_command(st->sc_link,
1353 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1354 	    (u_char *)buf, size, 0, 100000, NULL, flags | SCSI_DATA_IN));
1355 }
1356 
1357 /*
1358  * Ask the drive what it's min and max blk sizes are.
1359  */
1360 int
1361 st_read_block_limits(st, flags)
1362 	struct st_softc *st;
1363 	int flags;
1364 {
1365 	struct scsi_block_limits cmd;
1366 	struct scsi_block_limits_data block_limits;
1367 	struct scsipi_link *sc_link = st->sc_link;
1368 	int error;
1369 
1370 	/*
1371 	 * First check if we have it all loaded
1372 	 */
1373 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1374 		return (0);
1375 
1376 	/*
1377 	 * do a 'Read Block Limits'
1378 	 */
1379 	bzero(&cmd, sizeof(cmd));
1380 	cmd.opcode = READ_BLOCK_LIMITS;
1381 
1382 	/*
1383 	 * do the command, update the global values
1384 	 */
1385 	error = scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1386 	    sizeof(cmd), (u_char *)&block_limits, sizeof(block_limits),
1387 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1388 	if (error)
1389 		return (error);
1390 
1391 	st->blkmin = _2btol(block_limits.min_length);
1392 	st->blkmax = _3btol(block_limits.max_length);
1393 
1394 	SC_DEBUG(sc_link, SDEV_DB3,
1395 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1396 	return (0);
1397 }
1398 
1399 /*
1400  * Get the scsi driver to send a full inquiry to the
1401  * device and use the results to fill out the global
1402  * parameter structure.
1403  *
1404  * called from:
1405  * attach
1406  * open
1407  * ioctl (to reset original blksize)
1408  */
1409 int
1410 st_mode_sense(st, flags)
1411 	struct st_softc *st;
1412 	int flags;
1413 {
1414 	u_int scsipi_sense_len;
1415 	int error;
1416 	struct scsi_mode_sense cmd;
1417 	struct scsipi_sense {
1418 		struct scsi_mode_header header;
1419 		struct scsi_blk_desc blk_desc;
1420 		u_char sense_data[MAX_PAGE_0_SIZE];
1421 	} scsipi_sense;
1422 	struct scsipi_link *sc_link = st->sc_link;
1423 
1424 	scsipi_sense_len = 12 + st->page_0_size;
1425 
1426 	/*
1427 	 * Set up a mode sense
1428 	 */
1429 	bzero(&cmd, sizeof(cmd));
1430 	cmd.opcode = SCSI_MODE_SENSE;
1431 	cmd.length = scsipi_sense_len;
1432 
1433 	/*
1434 	 * do the command, but we don't need the results
1435 	 * just print them for our interest's sake, if asked,
1436 	 * or if we need it as a template for the mode select
1437 	 * store it away.
1438 	 */
1439 	error = scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1440 	    sizeof(cmd), (u_char *)&scsipi_sense, scsipi_sense_len,
1441 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1442 	if (error)
1443 		return (error);
1444 
1445 	st->numblks = _3btol(scsipi_sense.blk_desc.nblocks);
1446 	st->media_blksize = _3btol(scsipi_sense.blk_desc.blklen);
1447 	st->media_density = scsipi_sense.blk_desc.density;
1448 	if (scsipi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1449 		st->flags |= ST_READONLY;
1450 	SC_DEBUG(sc_link, SDEV_DB3,
1451 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1452 	    st->media_density, st->media_blksize,
1453 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1454 	SC_DEBUG(sc_link, SDEV_DB3,
1455 	    ("%sbuffered\n",
1456 	    scsipi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1457 	if (st->page_0_size)
1458 		bcopy(scsipi_sense.sense_data, st->sense_data,
1459 		    st->page_0_size);
1460 	sc_link->flags |= SDEV_MEDIA_LOADED;
1461 	return (0);
1462 }
1463 
1464 /*
1465  * Send a filled out parameter structure to the drive to
1466  * set it into the desire modes etc.
1467  */
1468 int
1469 st_mode_select(st, flags)
1470 	struct st_softc *st;
1471 	int flags;
1472 {
1473 	u_int scsi_select_len;
1474 	struct scsi_mode_select cmd;
1475 	struct scsi_select {
1476 		struct scsi_mode_header header;
1477 		struct scsi_blk_desc blk_desc;
1478 		u_char sense_data[MAX_PAGE_0_SIZE];
1479 	} scsi_select;
1480 	struct scsipi_link *sc_link = st->sc_link;
1481 
1482 	scsi_select_len = 12 + st->page_0_size;
1483 
1484 	/*
1485 	 * This quirk deals with drives that have only one valid mode
1486 	 * and think this gives them license to reject all mode selects,
1487 	 * even if the selected mode is the one that is supported.
1488 	 */
1489 	if (st->quirks & ST_Q_UNIMODAL) {
1490 		SC_DEBUG(sc_link, SDEV_DB3,
1491 		    ("not setting density 0x%x blksize 0x%x\n",
1492 		    st->density, st->blksize));
1493 		return (0);
1494 	}
1495 
1496 	/*
1497 	 * Set up for a mode select
1498 	 */
1499 	bzero(&cmd, sizeof(cmd));
1500 	cmd.opcode = SCSI_MODE_SELECT;
1501 	cmd.length = scsi_select_len;
1502 
1503 	bzero(&scsi_select, scsi_select_len);
1504 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1505 	scsi_select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
1506 	scsi_select.blk_desc.density = st->density;
1507 	if (st->flags & ST_DONTBUFFER)
1508 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
1509 	else
1510 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1511 	if (st->flags & ST_FIXEDBLOCKS)
1512 		_lto3b(st->blksize, scsi_select.blk_desc.blklen);
1513 	if (st->page_0_size)
1514 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1515 
1516 	/*
1517 	 * do the command
1518 	 */
1519 	return (scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1520 	    sizeof(cmd), (u_char *)&scsi_select, scsi_select_len,
1521 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT));
1522 }
1523 
1524 int
1525 st_cmprss(st, onoff)
1526 	struct st_softc *st;
1527 	int onoff;
1528 {
1529 	u_int scsi_dlen;
1530 	struct scsi_mode_select mcmd;
1531 	struct scsi_mode_sense scmd;
1532 	struct scsi_select {
1533 		struct scsi_mode_header header;
1534 		struct scsi_blk_desc blk_desc;
1535 		u_char pdata[max(sizeof(struct scsi_tape_dev_conf_page),
1536 		    sizeof(struct scsi_tape_dev_compression_page))];
1537 	} scsi_pdata;
1538 	struct scsi_tape_dev_conf_page *ptr;
1539 	struct scsi_tape_dev_compression_page *cptr;
1540 	struct scsipi_link *sc_link = st->sc_link;
1541 	int error, ison, flags;
1542 
1543 	scsi_dlen = sizeof(scsi_pdata);
1544 	bzero(&scsi_pdata, scsi_dlen);
1545 
1546 	/*
1547 	 * Set up for a mode sense.
1548 	 * Do DATA COMPRESSION page first.
1549 	 */
1550 	bzero(&scmd, sizeof(scmd));
1551 	scmd.opcode = SCSI_MODE_SENSE;
1552 	scmd.page = SMS_PAGE_CTRL_CURRENT | 0xf;
1553 	scmd.length = scsi_dlen;
1554 
1555 	flags = SCSI_SILENT;
1556 
1557 	/*
1558 	 * Do the MODE SENSE command...
1559 	 */
1560 again:
1561 	error = scsipi_command(sc_link,
1562 	    (struct scsipi_generic *)&scmd, sizeof(scmd),
1563 	    (u_char *)&scsi_pdata, scsi_dlen,
1564 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1565 
1566 	if (error) {
1567 		if (scmd.byte2 != SMS_DBD) {
1568 			scmd.byte2 = SMS_DBD;
1569 			goto again;
1570 		}
1571 		return (error);
1572 	}
1573 
1574 	if (scsi_pdata.header.blk_desc_len)
1575 		ptr = (struct scsi_tape_dev_conf_page *) scsi_pdata.pdata;
1576 	else
1577 		ptr = (struct scsi_tape_dev_conf_page *) &scsi_pdata.blk_desc;
1578 
1579 	if ((scmd.page & SMS_PAGE_CODE) == 0xf) {
1580 		cptr = (struct scsi_tape_dev_compression_page *) ptr;
1581 		ison = (cptr->dce_dcc & DCP_DCE) != 0;
1582 		if (onoff)
1583 			cptr->dce_dcc |= DCP_DCE;
1584 		else
1585 			cptr->dce_dcc &= ~DCP_DCE;
1586 		cptr->pagecode &= ~0x80;
1587 	} else {
1588 		ison =  (ptr->sel_comp_alg != 0);
1589 		if (onoff)
1590 			ptr->sel_comp_alg = 1;
1591 		else
1592 			ptr->sel_comp_alg = 0;
1593 		ptr->pagecode &= ~0x80;
1594 	}
1595 	onoff = onoff ? 1 : 0;
1596 	/*
1597 	 * There might be a virtue in actually doing the MODE SELECTS,
1598 	 * but let's not clog the bus over it.
1599 	 */
1600 	if (onoff == ison)
1601 		return (0);
1602 
1603 	/*
1604 	 * Set up for a mode select
1605 	 */
1606 
1607 	scsi_pdata.header.data_length = 0;
1608 	scsi_pdata.header.medium_type = 0;
1609 	if ((st->flags & ST_DONTBUFFER) == 0)
1610 		scsi_pdata.header.dev_spec = SMH_DSP_BUFF_MODE_ON;
1611 	else
1612 		scsi_pdata.header.dev_spec = 0;
1613 
1614 	bzero(&mcmd, sizeof(mcmd));
1615 	mcmd.opcode = SCSI_MODE_SELECT;
1616 	mcmd.byte2 = SMS_PF;
1617 	mcmd.length = scsi_dlen;
1618 	if (scsi_pdata.header.blk_desc_len) {
1619 		scsi_pdata.blk_desc.density = 0;
1620 		scsi_pdata.blk_desc.nblocks[0] = 0;
1621 		scsi_pdata.blk_desc.nblocks[1] = 0;
1622 		scsi_pdata.blk_desc.nblocks[2] = 0;
1623 	}
1624 
1625 	/*
1626 	 * Do the command
1627 	 */
1628 	error = scsipi_command(sc_link,
1629 	    (struct scsipi_generic *)&mcmd, sizeof(mcmd),
1630 	    (u_char *)&scsi_pdata, scsi_dlen,
1631 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1632 
1633 	if (error && (scmd.page & SMS_PAGE_CODE) == 0xf) {
1634 		/*
1635 		 * Try DEVICE CONFIGURATION page.
1636 		 */
1637 		scmd.page = SMS_PAGE_CTRL_CURRENT | 0x10;
1638 		goto again;
1639 	}
1640 	return (error);
1641 }
1642 /*
1643  * issue an erase command
1644  */
1645 int
1646 st_erase(st, full, flags)
1647 	struct st_softc *st;
1648 	int full, flags;
1649 {
1650 	struct scsi_erase cmd;
1651 
1652 	/*
1653 	 * Full erase means set LONG bit in erase command, which asks
1654 	 * the drive to erase the entire unit.  Without this bit, we're
1655 	 * asking the drive to write an erase gap.
1656 	 */
1657 	bzero(&cmd, sizeof(cmd));
1658 	cmd.opcode = ERASE;
1659 	if (full)
1660 		cmd.byte2 = SE_IMMED|SE_LONG;
1661 	else
1662 		cmd.byte2 = SE_IMMED;
1663 
1664 	/*
1665 	 * XXX We always do this asynchronously, for now.  How long should
1666 	 * we wait if we want to (eventually) to it synchronously?
1667 	 */
1668 	return (scsipi_command(st->sc_link,
1669 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1670 	    0, 0, ST_RETRIES, 5000, NULL, flags));
1671 }
1672 
1673 /*
1674  * skip N blocks/filemarks/seq filemarks/eom
1675  */
1676 int
1677 st_space(st, number, what, flags)
1678 	struct st_softc *st;
1679 	u_int what;
1680 	int flags;
1681 	int number;
1682 {
1683 	struct scsi_space cmd;
1684 	int error;
1685 
1686 	switch (what) {
1687 	case SP_BLKS:
1688 		if (st->flags & ST_PER_ACTION) {
1689 			if (number > 0) {
1690 				st->flags &= ~ST_PER_ACTION;
1691 				return (EIO);
1692 			} else if (number < 0) {
1693 				if (st->flags & ST_AT_FILEMARK) {
1694 					/*
1695 					 * Handling of ST_AT_FILEMARK
1696 					 * in st_space will fill in the
1697 					 * right file mark count.
1698 					 */
1699 					error = st_space(st, 0, SP_FILEMARKS,
1700 					    flags);
1701 					if (error)
1702 						return (error);
1703 				}
1704 				if (st->flags & ST_BLANK_READ) {
1705 					st->flags &= ~ST_BLANK_READ;
1706 					return (EIO);
1707 				}
1708 				st->flags &= ~ST_EIO_PENDING;
1709 			}
1710 		}
1711 		break;
1712 	case SP_FILEMARKS:
1713 		if (st->flags & ST_EIO_PENDING) {
1714 			if (number > 0) {
1715 				/* pretend we just discovered the error */
1716 				st->flags &= ~ST_EIO_PENDING;
1717 				return (EIO);
1718 			} else if (number < 0) {
1719 				/* back away from the error */
1720 				st->flags &= ~ST_EIO_PENDING;
1721 			}
1722 		}
1723 		if (st->flags & ST_AT_FILEMARK) {
1724 			st->flags &= ~ST_AT_FILEMARK;
1725 			number--;
1726 		}
1727 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1728 			/* back away from unwritten tape */
1729 			st->flags &= ~ST_BLANK_READ;
1730 			number++;	/* XXX dubious */
1731 		}
1732 		break;
1733 	case SP_EOM:
1734 		if (st->flags & ST_EIO_PENDING) {
1735 			/* pretend we just discovered the error */
1736 			st->flags &= ~ST_EIO_PENDING;
1737 			return (EIO);
1738 		}
1739 		if (st->flags & ST_AT_FILEMARK)
1740 			st->flags &= ~ST_AT_FILEMARK;
1741 		break;
1742 	}
1743 	if (number == 0)
1744 		return (0);
1745 
1746 	bzero(&cmd, sizeof(cmd));
1747 	cmd.opcode = SPACE;
1748 	cmd.byte2 = what;
1749 	_lto3b(number, cmd.number);
1750 
1751 	return (scsipi_command(st->sc_link,
1752 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1753 	    0, 0, 0, 900000, NULL, flags));
1754 }
1755 
1756 /*
1757  * write N filemarks
1758  */
1759 int
1760 st_write_filemarks(st, number, flags)
1761 	struct st_softc *st;
1762 	int flags;
1763 	int number;
1764 {
1765 	struct scsi_write_filemarks cmd;
1766 
1767 	/*
1768 	 * It's hard to write a negative number of file marks.
1769 	 * Don't try.
1770 	 */
1771 	if (number < 0)
1772 		return (EINVAL);
1773 	switch (number) {
1774 	case 0:		/* really a command to sync the drive's buffers */
1775 		break;
1776 	case 1:
1777 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1778 			st->flags &= ~ST_WRITTEN;
1779 		else
1780 			st->flags |= ST_FM_WRITTEN;
1781 		st->flags &= ~ST_PER_ACTION;
1782 		break;
1783 	default:
1784 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1785 	}
1786 
1787 	bzero(&cmd, sizeof(cmd));
1788 	cmd.opcode = WRITE_FILEMARKS;
1789 	_lto3b(number, cmd.number);
1790 
1791 	return (scsipi_command(st->sc_link,
1792 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1793 	    0, 0, 0, 100000, NULL, flags));
1794 }
1795 
1796 /*
1797  * Make sure the right number of file marks is on tape if the
1798  * tape has been written.  If the position argument is true,
1799  * leave the tape positioned where it was originally.
1800  *
1801  * nmarks returns the number of marks to skip (or, if position
1802  * true, which were skipped) to get back original position.
1803  */
1804 int
1805 st_check_eod(st, position, nmarks, flags)
1806 	struct st_softc *st;
1807 	boolean position;
1808 	int *nmarks;
1809 	int flags;
1810 {
1811 	int error;
1812 
1813 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1814 	default:
1815 		*nmarks = 0;
1816 		return (0);
1817 	case ST_WRITTEN:
1818 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1819 		*nmarks = 1;
1820 		break;
1821 	case ST_WRITTEN | ST_2FM_AT_EOD:
1822 		*nmarks = 2;
1823 	}
1824 	error = st_write_filemarks(st, *nmarks, flags);
1825 	if (position && !error)
1826 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1827 	return (error);
1828 }
1829 
1830 /*
1831  * load/unload/retension
1832  */
1833 int
1834 st_load(st, type, flags)
1835 	struct st_softc *st;
1836 	u_int type;
1837 	int flags;
1838 {
1839 	struct scsi_load cmd;
1840 
1841 	if (type != LD_LOAD) {
1842 		int error;
1843 		int nmarks;
1844 
1845 		error = st_check_eod(st, FALSE, &nmarks, flags);
1846 		if (error)
1847 			return (error);
1848 	}
1849 	if (st->quirks & ST_Q_IGNORE_LOADS)
1850 		return (0);
1851 
1852 	bzero(&cmd, sizeof(cmd));
1853 	cmd.opcode = LOAD;
1854 	cmd.how = type;
1855 
1856 	return (scsipi_command(st->sc_link,
1857 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1858 	    0, 0, ST_RETRIES, 300000, NULL, flags));
1859 }
1860 
1861 /*
1862  *  Rewind the device
1863  */
1864 int
1865 st_rewind(st, immediate, flags)
1866 	struct st_softc *st;
1867 	u_int immediate;
1868 	int flags;
1869 {
1870 	struct scsi_rewind cmd;
1871 	int error;
1872 	int nmarks;
1873 
1874 	error = st_check_eod(st, FALSE, &nmarks, flags);
1875 	if (error)
1876 		return (error);
1877 	st->flags &= ~ST_PER_ACTION;
1878 
1879 	bzero(&cmd, sizeof(cmd));
1880 	cmd.opcode = REWIND;
1881 	cmd.byte2 = immediate;
1882 
1883 	return (scsipi_command(st->sc_link,
1884 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1885 	    0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL, flags));
1886 }
1887 
1888 int
1889 st_rdpos(st, hard, blkptr)
1890 	struct st_softc *st;
1891 	int hard;
1892 	u_int32_t *blkptr;
1893 {
1894 	int error;
1895 	u_int8_t posdata[20];
1896 	struct scsi_tape_read_position cmd;
1897 
1898 	/*
1899 	 * First flush any pending writes...
1900 	 */
1901 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1902 
1903 	/*
1904 	 * The latter case is for 'write protected' tapes
1905 	 * which are too stupid to recognize a zero count
1906 	 * for writing filemarks as a no-op.
1907 	 */
1908 	if (error != 0 && error != EACCES)
1909 		return (error);
1910 
1911 	bzero(&cmd, sizeof(cmd));
1912 	bzero(&posdata, sizeof(posdata));
1913 	cmd.opcode = READ_POSITION;
1914 	if (hard)
1915 		cmd.byte1 = 1;
1916 
1917 	error = scsipi_command(st->sc_link,
1918 	    (struct scsipi_generic *)&cmd, sizeof(cmd), (u_char *)&posdata,
1919 	    sizeof(posdata), ST_RETRIES, 30000, NULL,
1920 	    SCSI_SILENT | SCSI_DATA_IN);
1921 
1922 	if (error == 0) {
1923 #if	0
1924 		printf("posdata:");
1925 		for (hard = 0; hard < sizeof(posdata); hard++)
1926 			printf("%02x ", posdata[hard] & 0xff);
1927 		printf("\n");
1928 #endif
1929 		if (posdata[0] & 0x4)	/* Block Position Unknown */
1930 			error = EINVAL;
1931 		else
1932 			*blkptr = _4btol(&posdata[4]);
1933 	}
1934 	return (error);
1935 }
1936 
1937 int
1938 st_setpos(st, hard, blkptr)
1939 	struct st_softc *st;
1940 	int hard;
1941 	u_int32_t *blkptr;
1942 {
1943 	int error;
1944 	struct scsipi_generic cmd;
1945 
1946 	/*
1947 	 * First flush any pending writes. Strictly speaking,
1948 	 * we're not supposed to have to worry about this,
1949 	 * but let's be untrusting.
1950 	 */
1951 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1952 
1953 	/*
1954 	 * The latter case is for 'write protected' tapes
1955 	 * which are too stupid to recognize a zero count
1956 	 * for writing filemarks as a no-op.
1957 	 */
1958 	if (error != 0 && error != EACCES)
1959 		return (error);
1960 
1961 	bzero(&cmd, sizeof(cmd));
1962 	cmd.opcode = LOCATE;
1963 	if (hard)
1964 		cmd.bytes[0] = 1 << 2;
1965 	_lto4b(*blkptr, &cmd.bytes[2]);
1966 	error = scsipi_command(st->sc_link, &cmd, sizeof(cmd),
1967 	    NULL, 0, ST_RETRIES, 900000, NULL, 0);
1968 	/*
1969 	 * XXX: Note file && block number position now unknown (if
1970 	 * XXX: these things ever start being maintained in this driver)
1971 	 */
1972 	return (error);
1973 }
1974 
1975 
1976 /*
1977  * Look at the returned sense and act on the error and detirmine
1978  * The unix error number to pass back... (0 = report no error)
1979  *                            (-1 = continue processing)
1980  */
1981 int
1982 st_interpret_sense(xs)
1983 	struct scsipi_xfer *xs;
1984 {
1985 	struct scsipi_link *sc_link = xs->sc_link;
1986 	struct scsipi_sense_data *sense = &xs->sense.scsi_sense;
1987 	struct buf *bp = xs->bp;
1988 	struct st_softc *st = sc_link->device_softc;
1989 	u_int8_t key;
1990 	int32_t info;
1991 
1992 	/*
1993 	 * Get the sense fields and work out what code
1994 	 */
1995 	if (sense->error_code & SSD_ERRCODE_VALID)
1996 		info = _4btol(sense->info);
1997 	else
1998 		info = xs->datalen;	/* bad choice if fixed blocks */
1999 	if ((sc_link->flags & SDEV_OPEN) == 0)
2000 		return (-1);		/* not open yet, let generic handle */
2001 	else if ((sense->error_code & SSD_ERRCODE) != 0x70)
2002 		return (-1);		/* let the generic code handle it */
2003 #ifdef SCSIVERBOSE
2004 	else if ((xs->flags & SCSI_SILENT) == 0)
2005 		scsi_print_sense(xs, 0);    /* tell folks what happened */
2006 #endif
2007 	if (st->flags & ST_FIXEDBLOCKS) {
2008 		xs->resid = info * st->blksize;
2009 		if (sense->flags & SSD_EOM) {
2010 			st->flags |= ST_EIO_PENDING;
2011 			if (bp)
2012 				bp->b_resid = xs->resid;
2013 		}
2014 		if (sense->flags & SSD_FILEMARK) {
2015 			st->flags |= ST_AT_FILEMARK;
2016 			if (bp)
2017 				bp->b_resid = xs->resid;
2018 		}
2019 		if (sense->flags & SSD_ILI) {
2020 			st->flags |= ST_EIO_PENDING;
2021 			if (bp)
2022 				bp->b_resid = xs->resid;
2023 			if (sense->error_code & SSD_ERRCODE_VALID &&
2024 			    (xs->flags & SCSI_SILENT) == 0)
2025 				printf("%s: block wrong size, %d blocks residual\n",
2026 				    st->sc_dev.dv_xname, info);
2027 
2028 			/*
2029 			 * This quirk code helps the drive read
2030 			 * the first tape block, regardless of
2031 			 * format.  That is required for these
2032 			 * drives to return proper MODE SENSE
2033 			 * information.
2034 			 */
2035 			if ((st->quirks & ST_Q_SENSE_HELP) &&
2036 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
2037 				st->blksize -= 512;
2038 		}
2039 		/*
2040 		 * If data wanted and no data was tranfered, do it immediatly
2041 		 */
2042 		if (xs->datalen && xs->resid >= xs->datalen) {
2043 			if (st->flags & ST_EIO_PENDING)
2044 				return (EIO);
2045 			if (st->flags & ST_AT_FILEMARK) {
2046 				if (bp)
2047 					bp->b_resid = xs->resid;
2048 				return (0);
2049 			}
2050 		}
2051 	} else {		/* must be variable mode */
2052 		xs->resid = xs->datalen;	/* to be sure */
2053 		if (sense->flags & SSD_EOM)
2054 			return (EIO);
2055 		if (sense->flags & SSD_FILEMARK) {
2056 			if (bp)
2057 				bp->b_resid = bp->b_bcount;
2058 			return (0);
2059 		}
2060 		if (sense->flags & SSD_ILI) {
2061 			if (info < 0) {
2062 				/*
2063 				 * the record was bigger than the read
2064 				 */
2065 				if ((xs->flags & SCSI_SILENT) == 0)
2066 					printf("%s: %d-byte record too big\n",
2067 					    st->sc_dev.dv_xname,
2068 					    xs->datalen - info);
2069 				return (EIO);
2070 			}
2071 			xs->resid = info;
2072 			if (bp)
2073 				bp->b_resid = info;
2074 		}
2075 	}
2076 	key = sense->flags & SSD_KEY;
2077 
2078 	if (key == 0x8) {
2079 		/*
2080 		 * This quirk code helps the drive read the
2081 		 * first tape block, regardless of format.  That
2082 		 * is required for these drives to return proper
2083 		 * MODE SENSE information.
2084 		 */
2085 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2086 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
2087 			/* still starting */
2088 			st->blksize -= 512;
2089 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2090 			st->flags |= ST_BLANK_READ;
2091 			xs->resid = xs->datalen;
2092 			if (bp) {
2093 				bp->b_resid = xs->resid;
2094 				/* return an EOF */
2095 			}
2096 			return (0);
2097 		}
2098 	}
2099 	return (-1);		/* let the default/generic handler handle it */
2100 }
2101 
2102 /*
2103  * The quirk here is that the drive returns some value to st_mode_sense
2104  * incorrectly until the tape has actually passed by the head.
2105  *
2106  * The method is to set the drive to large fixed-block state (user-specified
2107  * density and 1024-byte blocks), then read and rewind to get it to sense the
2108  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2109  * work, as a last resort, try variable- length blocks.  The result will be
2110  * the ability to do an accurate st_mode_sense.
2111  *
2112  * We know we can do a rewind because we just did a load, which implies rewind.
2113  * Rewind seems preferable to space backward if we have a virgin tape.
2114  *
2115  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2116  * error processing, both part of st_interpret_sense.
2117  */
2118 int
2119 st_touch_tape(st)
2120 	struct st_softc *st;
2121 {
2122 	char *buf;
2123 	int readsize;
2124 	int error;
2125 
2126 	buf = malloc(1024, M_TEMP, M_NOWAIT);
2127 	if (buf == NULL)
2128 		return (ENOMEM);
2129 
2130 	if ((error = st_mode_sense(st, 0)) != 0)
2131 		goto bad;
2132 	st->blksize = 1024;
2133 	do {
2134 		switch (st->blksize) {
2135 		case 512:
2136 		case 1024:
2137 			readsize = st->blksize;
2138 			st->flags |= ST_FIXEDBLOCKS;
2139 			break;
2140 		default:
2141 			readsize = 1;
2142 			st->flags &= ~ST_FIXEDBLOCKS;
2143 		}
2144 		if ((error = st_mode_select(st, 0)) != 0)
2145 			goto bad;
2146 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
2147 		if ((error = st_rewind(st, 0, 0)) != 0) {
2148 bad:			free(buf, M_TEMP);
2149 			return (error);
2150 		}
2151 	} while (readsize != 1 && readsize > st->blksize);
2152 
2153 	free(buf, M_TEMP);
2154 	return (0);
2155 }
2156 
2157 int
2158 stdump(dev, blkno, va, size)
2159 	dev_t dev;
2160 	daddr_t blkno;
2161 	caddr_t va;
2162 	size_t size;
2163 {
2164 
2165 	/* Not implemented. */
2166 	return (ENXIO);
2167 }
2168