xref: /netbsd-src/sys/dev/scsipi/st.c (revision 7c7c171d130af9949261bc7dce2150a03c3d239c)
1 /*	$NetBSD: st.c,v 1.89 1998/02/13 08:12:40 enami 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/scsipi_all.h>
77 #include <dev/scsipi/scsi_all.h>
78 #include <dev/scsipi/scsi_tape.h>
79 #include <dev/scsipi/scsiconf.h>
80 
81 /* Defines for device specific stuff */
82 #define DEF_FIXED_BSIZE  512
83 #define	ST_RETRIES	4	/* only on non IO commands */
84 
85 #define STMODE(z)	( minor(z)       & 0x03)
86 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
87 #define STUNIT(z)	((minor(z) >> 4)       )
88 #define CTLMODE		3
89 
90 #define	FALSE		0
91 #define	TRUE		1
92 
93 /*
94  * Maximum density code known.
95  */
96 #define SCSI_2_MAX_DENSITY_CODE	0x45
97 
98 /*
99  * Define various devices that we know mis-behave in some way,
100  * and note how they are bad, so we can correct for them
101  */
102 struct modes {
103 	u_int quirks;			/* same definitions as in quirkdata */
104 	int blksize;
105 	u_int8_t density;
106 };
107 
108 struct quirkdata {
109 	u_int quirks;
110 #define	ST_Q_FORCE_BLKSIZE	0x0001
111 #define	ST_Q_SENSE_HELP		0x0002	/* must do READ for good MODE SENSE */
112 #define	ST_Q_IGNORE_LOADS	0x0004
113 #define	ST_Q_BLKSIZE		0x0008	/* variable-block media_blksize > 0 */
114 #define	ST_Q_UNIMODAL		0x0010	/* unimode drive rejects mode select */
115 	u_int page_0_size;
116 #define	MAX_PAGE_0_SIZE	64
117 	struct modes modes[4];
118 };
119 
120 struct st_quirk_inquiry_pattern {
121 	struct scsipi_inquiry_pattern pattern;
122 	struct quirkdata quirkdata;
123 };
124 
125 struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
126 	{{T_SEQUENTIAL, T_REMOV,
127 	 "        ", "                ", "    "}, {0, 0, {
128 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
129 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
130 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
131 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
132 	}}},
133 	{{T_SEQUENTIAL, T_REMOV,
134 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
135 		{0, 0, 0},				/* minor 0-3 */
136 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
137 		{0, 0, QIC_150},			/* minor 8-11 */
138 		{0, 0, QIC_120}				/* minor 12-15 */
139 	}}},
140  	{{T_SEQUENTIAL, T_REMOV,
141  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
142 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
143 		{0, 0, QIC_525},			/* minor 4-7 */
144 		{0, 0, QIC_150},			/* minor 8-11 */
145 		{0, 0, QIC_120}				/* minor 12-15 */
146 	}}},
147 	/*
148 	 * At least -005 and -007 need this.  I'll assume they all do unless I
149 	 * hear otherwise.  - mycroft, 31MAR1994
150 	 */
151 	{{T_SEQUENTIAL, T_REMOV,
152 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
153 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
154 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
155 		{0, 0, QIC_150},			/* minor 8-11 */
156 		{0, 0, QIC_120}				/* minor 12-15 */
157 	}}},
158 	/*
159 	 * One user reports that this works for his tape drive.  It probably
160 	 * needs more work.  - mycroft, 09APR1994
161 	 */
162 	{{T_SEQUENTIAL, T_REMOV,
163 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
164 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
165 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
166 		{0, 0, QIC_150},			/* minor 8-11 */
167 		{0, 0, QIC_120}				/* minor 12-15 */
168 	}}},
169 	{{T_SEQUENTIAL, T_REMOV,
170 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
171 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
172 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
173 		{0, 0, QIC_150},			/* minor 8-11 */
174 		{0, 0, QIC_120}				/* minor 12-15 */
175 	}}},
176 	{{T_SEQUENTIAL, T_REMOV,
177 	 "ARCHIVE ", "VIPER 150  21247", ""},     {0, 12, {
178 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
179 		{0, 0, QIC_150},			/* minor 4-7 */
180 		{0, 0, QIC_120},			/* minor 8-11 */
181 		{0, 0, QIC_24}				/* minor 12-15 */
182 	}}},
183 	{{T_SEQUENTIAL, T_REMOV,
184 	 "ARCHIVE ", "VIPER 150  21531", ""},     {0, 12, {
185 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
186 		{0, 0, QIC_150},			/* minor 4-7 */
187 		{0, 0, QIC_120},			/* minor 8-11 */
188 		{0, 0, QIC_24}				/* minor 12-15 */
189 	}}},
190 	{{T_SEQUENTIAL, T_REMOV,
191 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
192 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
193 		{0, 0, QIC_11},				/* minor 4-7 */
194 		{0, 0, QIC_24},				/* minor 8-11 */
195 		{0, 0, QIC_24}				/* minor 12-15 */
196 	}}},
197 	{{T_SEQUENTIAL, T_REMOV,
198 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
199 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
200 		{0, 0, QIC_24},				/* minor 4-7 */
201 		{0, 0, QIC_120},			/* minor 8-11 */
202 		{0, 0, QIC_150}				/* minor 12-15 */
203 	}}},
204 	{{T_SEQUENTIAL, T_REMOV,
205 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
206 		{0, 0, 0},				/* minor 0-3 */
207 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
208 		{0, 0, QIC_150},			/* minor 8-11 */
209 		{0, 0, QIC_120}				/* minor 12-15 */
210 	}}},
211 	{{T_SEQUENTIAL, T_REMOV,
212 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
213 		{0, 0, 0},				/* minor 0-3 */
214 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
215 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
216 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
217 	}}},
218 	{{T_SEQUENTIAL, T_REMOV,
219 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
220 		{0, 0, 0},				/* minor 0-3 */
221 		{0, 0, 0},				/* minor 4-7 */
222 		{0, 0, 0},				/* minor 8-11 */
223 		{0, 0, 0}				/* minor 12-15 */
224 	}}},
225 	{{T_SEQUENTIAL, T_REMOV,
226 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
227 		{0, 0, 0},				/* minor 0-3 */
228 		{0, 0, 0},				/* minor 4-7 */
229 		{0, 0, 0},				/* minor 8-11 */
230 		{0, 0, 0}				/* minor 12-15 */
231 	}}},
232 	{{T_SEQUENTIAL, T_REMOV,
233 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
234 		{0, 0, QIC_3095},			/* minor 0-3 */
235 		{0, 0, QIC_3095},			/* minor 4-7 */
236 		{0, 0, QIC_3095},			/* minor 8-11 */
237 		{0, 0, QIC_3095},			/* minor 12-15 */
238 	}}},
239 #if 0
240 	{{T_SEQUENTIAL, T_REMOV,
241 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
242 		{0, 0, 0},				/* minor 0-3 */
243 		{0, 0, 0},				/* minor 4-7 */
244 		{0, 0, 0},				/* minor 8-11 */
245 		{0, 0, 0}				/* minor 12-15 */
246 	}}},
247 #endif
248 };
249 
250 #define NOEJECT 0
251 #define EJECT 1
252 
253 struct st_softc {
254 	struct device sc_dev;
255 /*--------------------present operating parameters, flags etc.---------------*/
256 	int flags;		/* see below                         */
257 	u_int quirks;		/* quirks for the open mode          */
258 	int blksize;		/* blksize we are using              */
259 	u_int8_t density;	/* present density                   */
260 	u_int page_0_size;	/* size of page 0 data		     */
261 	u_int last_dsty;	/* last density opened               */
262 /*--------------------device/scsi parameters---------------------------------*/
263 	struct scsipi_link *sc_link;	/* our link to the adpter etc.       */
264 /*--------------------parameters reported by the device ---------------------*/
265 	int blkmin;		/* min blk size                       */
266 	int blkmax;		/* max blk size                       */
267 	struct quirkdata *quirkdata;	/* if we have a rogue entry          */
268 /*--------------------parameters reported by the device for this media-------*/
269 	u_long numblks;		/* nominal blocks capacity            */
270 	int media_blksize;	/* 0 if not ST_FIXEDBLOCKS            */
271 	u_int8_t media_density;	/* this is what it said when asked    */
272 /*--------------------quirks for the whole drive-----------------------------*/
273 	u_int drive_quirks;	/* quirks of this drive               */
274 /*--------------------How we should set up when opening each minor device----*/
275 	struct modes modes[4];	/* plus more for each mode            */
276 	u_int8_t  modeflags[4];	/* flags for the modes                */
277 #define DENSITY_SET_BY_USER	0x01
278 #define DENSITY_SET_BY_QUIRK	0x02
279 #define BLKSIZE_SET_BY_USER	0x04
280 #define BLKSIZE_SET_BY_QUIRK	0x08
281 /*--------------------storage for sense data returned by the drive-----------*/
282 	u_char sense_data[MAX_PAGE_0_SIZE];	/*
283 						 * additional sense data needed
284 						 * for mode sense/select.
285 						 */
286 	struct buf buf_queue;		/* the queue of pending IO */
287 					/* operations */
288 #if NRND > 0
289 	rndsource_element_t	rnd_source;
290 #endif
291 };
292 
293 
294 #ifdef __BROKEN_INDIRECT_CONFIG
295 int	stmatch __P((struct device *, void *, void *));
296 #else
297 int	stmatch __P((struct device *, struct cfdata *, void *));
298 #endif
299 void	stattach __P((struct device *, struct device *, void *));
300 void	st_identify_drive __P((struct st_softc *,
301 	    struct scsipi_inquiry_pattern *));
302 void	st_loadquirks __P((struct st_softc *));
303 int	st_mount_tape __P((dev_t, int));
304 void	st_unmount __P((struct st_softc *, boolean));
305 int	st_decide_mode __P((struct st_softc *, boolean));
306 void	ststart __P((void *));
307 void	stdone __P((struct scsipi_xfer *));
308 int	st_read __P((struct st_softc *, char *, int, int));
309 int	st_read_block_limits __P((struct st_softc *, int));
310 int	st_mode_sense __P((struct st_softc *, int));
311 int	st_mode_select __P((struct st_softc *, int));
312 int	st_cmprss __P((struct st_softc *, int));
313 int	st_space __P((struct st_softc *, int, u_int, int));
314 int	st_write_filemarks __P((struct st_softc *, int, int));
315 int	st_check_eod __P((struct st_softc *, boolean, int *, int));
316 int	st_load __P((struct st_softc *, u_int, int));
317 int	st_rewind __P((struct st_softc *, u_int, int));
318 int	st_interpret_sense __P((struct scsipi_xfer *));
319 int	st_touch_tape __P((struct st_softc *));
320 int	st_erase __P((struct st_softc *, int full, int flags));
321 int	st_rdpos __P((struct st_softc *, int, u_int32_t *));
322 int	st_setpos __P((struct st_softc *, int, u_int32_t *));
323 
324 struct cfattach st_ca = {
325 	sizeof(struct st_softc), stmatch, stattach
326 };
327 
328 extern struct cfdriver st_cd;
329 
330 struct scsipi_device st_switch = {
331 	st_interpret_sense,
332 	ststart,
333 	NULL,
334 #if NRND > 0
335 	stdone,  /* only needed to gather timing data for randomness */
336 #else
337 	NULL,
338 #endif
339 };
340 
341 #define	ST_INFO_VALID	0x0001
342 #define	ST_BLOCK_SET	0x0002	/* block size, mode set by ioctl      */
343 #define	ST_WRITTEN	0x0004	/* data have been written, EOD needed */
344 #define	ST_FIXEDBLOCKS	0x0008
345 #define	ST_AT_FILEMARK	0x0010
346 #define	ST_EIO_PENDING	0x0020	/* we couldn't report it then (had data) */
347 #define	ST_NEW_MOUNT	0x0040	/* still need to decide mode             */
348 #define	ST_READONLY	0x0080	/* st_mode_sense says write protected */
349 #define	ST_FM_WRITTEN	0x0100	/*
350 				 * EOF file mark written  -- used with
351 				 * ~ST_WRITTEN to indicate that multiple file
352 				 * marks have been written
353 				 */
354 #define	ST_BLANK_READ	0x0200	/* BLANK CHECK encountered already */
355 #define	ST_2FM_AT_EOD	0x0400	/* write 2 file marks at EOD */
356 #define	ST_MOUNTED	0x0800	/* Device is presently mounted */
357 #define	ST_DONTBUFFER	0x1000	/* Disable buffering/caching */
358 
359 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
360 #define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN |	\
361 			 ST_FIXEDBLOCKS | ST_READONLY | ST_FM_WRITTEN |	\
362 			 ST_2FM_AT_EOD | ST_PER_ACTION)
363 
364 struct scsipi_inquiry_pattern st_patterns[] = {
365 	{T_SEQUENTIAL, T_REMOV,
366 	 "",         "",                 ""},
367 };
368 
369 int
370 stmatch(parent, match, aux)
371 	struct device *parent;
372 #ifdef __BROKEN_INDIRECT_CONFIG
373 	void *match;
374 #else
375 	struct cfdata *match;
376 #endif
377 	void *aux;
378 {
379 	struct scsipibus_attach_args *sa = aux;
380 	int priority;
381 
382 	(void)scsipi_inqmatch(&sa->sa_inqbuf,
383 	    (caddr_t)st_patterns, sizeof(st_patterns)/sizeof(st_patterns[0]),
384 	    sizeof(st_patterns[0]), &priority);
385 	return (priority);
386 }
387 
388 /*
389  * The routine called by the low level scsi routine when it discovers
390  * A device suitable for this driver
391  */
392 void
393 stattach(parent, self, aux)
394 	struct device *parent, *self;
395 	void *aux;
396 {
397 	struct st_softc *st = (void *)self;
398 	struct scsipibus_attach_args *sa = aux;
399 	struct scsipi_link *sc_link = sa->sa_sc_link;
400 
401 	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
402 
403 	/*
404 	 * Store information needed to contact our base driver
405 	 */
406 	st->sc_link = sc_link;
407 	sc_link->device = &st_switch;
408 	sc_link->device_softc = st;
409 	sc_link->openings = 1;
410 
411 	/*
412 	 * Check if the drive is a known criminal and take
413 	 * Any steps needed to bring it into line
414 	 */
415 	st_identify_drive(st, &sa->sa_inqbuf);
416 
417 	/*
418 	 * Use the subdriver to request information regarding
419 	 * the drive. We cannot use interrupts yet, so the
420 	 * request must specify this.
421 	 */
422 	printf("\n");
423 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
424 	if (scsipi_test_unit_ready(sc_link,
425 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE) ||
426 	    st_mode_sense(st,
427 	    SCSI_AUTOCONF | SCSI_SILENT | SCSI_IGNORE_MEDIA_CHANGE))
428 		printf("drive empty\n");
429 	else {
430 		printf("density code 0x%x, ", st->media_density);
431 		if (st->media_blksize > 0)
432 			printf("%d-byte", st->media_blksize);
433 		else
434 			printf("variable");
435 		printf(" blocks, write-%s\n",
436 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
437 	}
438 
439 	/*
440 	 * Set up the buf queue for this device
441 	 */
442 	st->buf_queue.b_active = 0;
443 	st->buf_queue.b_actf = 0;
444 	st->buf_queue.b_actb = &st->buf_queue.b_actf;
445 
446 #if NRND > 0
447 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname, RND_TYPE_TAPE);
448 #endif
449 }
450 
451 /*
452  * Use the inquiry routine in 'scsi_base' to get drive info so we can
453  * Further tailor our behaviour.
454  */
455 void
456 st_identify_drive(st, inqbuf)
457 	struct st_softc *st;
458 	struct scsipi_inquiry_pattern *inqbuf;
459 {
460 	struct st_quirk_inquiry_pattern *finger;
461 	int priority;
462 
463 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
464 	    (caddr_t)st_quirk_patterns,
465 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
466 	    sizeof(st_quirk_patterns[0]), &priority);
467 	if (priority != 0) {
468 		st->quirkdata = &finger->quirkdata;
469 		st->drive_quirks = finger->quirkdata.quirks;
470 		st->quirks = finger->quirkdata.quirks;	/* start value */
471 		st->page_0_size = finger->quirkdata.page_0_size;
472 		st_loadquirks(st);
473 	}
474 }
475 
476 /*
477  * initialise the subdevices to the default (QUIRK) state.
478  * this will remove any setting made by the system operator or previous
479  * operations.
480  */
481 void
482 st_loadquirks(st)
483 	struct st_softc *st;
484 {
485 	int i;
486 	struct	modes *mode;
487 	struct	modes *mode2;
488 
489 	mode = st->quirkdata->modes;
490 	mode2 = st->modes;
491 	for (i = 0; i < 4; i++) {
492 		bzero(mode2, sizeof(struct modes));
493 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
494 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
495 		    DENSITY_SET_BY_USER);
496 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
497 			mode2->blksize = mode->blksize;
498 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
499 		}
500 		if (mode->density) {
501 			mode2->density = mode->density;
502 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
503 		}
504 		mode++;
505 		mode2++;
506 	}
507 }
508 
509 /*
510  * open the device.
511  */
512 int
513 stopen(dev, flags, mode, p)
514 	dev_t dev;
515 	int flags;
516 	int mode;
517 	struct proc *p;
518 {
519 	int unit;
520 	u_int stmode, dsty;
521 	int error = 0;
522 	struct st_softc *st;
523 	struct scsipi_link *sc_link;
524 
525 	unit = STUNIT(dev);
526 	if (unit >= st_cd.cd_ndevs)
527 		return (ENXIO);
528 	st = st_cd.cd_devs[unit];
529 	if (st == NULL)
530 		return (ENXIO);
531 
532 	stmode = STMODE(dev);
533 	dsty = STDSTY(dev);
534 	sc_link = st->sc_link;
535 
536 	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
537 	    unit, st_cd.cd_ndevs));
538 
539 	/*
540 	 * Only allow one at a time
541 	 */
542 	if (sc_link->flags & SDEV_OPEN) {
543 		printf("%s: already open\n", st->sc_dev.dv_xname);
544 		return (EBUSY);
545 	}
546 
547 	/*
548 	 * Catch any unit attention errors.
549 	 */
550 	error = scsipi_test_unit_ready(sc_link, SCSI_IGNORE_MEDIA_CHANGE |
551 	    (stmode == CTLMODE ? SCSI_IGNORE_NOT_READY : 0));
552 	if (error)
553 		goto bad;
554 
555 	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
556 
557 	/*
558 	 * If the mode is 3 (e.g. minor = 3,7,11,15)
559 	 * then the device has been opened to set defaults
560 	 * This mode does NOT ALLOW I/O, only ioctls
561 	 */
562 	if (stmode == CTLMODE)
563 		return (0);
564 
565 	/*
566 	 * if it's a different mode, or if the media has been
567 	 * invalidated, unmount the tape from the previous
568 	 * session but continue with open processing
569 	 */
570 	if (st->last_dsty != dsty || !(sc_link->flags & SDEV_MEDIA_LOADED))
571 		st_unmount(st, NOEJECT);
572 
573 	/*
574 	 * If we are not mounted, then we should start a new
575 	 * mount session.
576 	 */
577 	if (!(st->flags & ST_MOUNTED)) {
578 		st_mount_tape(dev, flags);
579 		st->last_dsty = dsty;
580 	}
581 
582 	/*
583 	 * Make sure that a tape opened in write-only mode will have
584 	 * file marks written on it when closed, even if not written to.
585 	 * This is for SUN compatibility
586 	 */
587 	if ((flags & O_ACCMODE) == FWRITE)
588 		st->flags |= ST_WRITTEN;
589 
590 	SC_DEBUG(sc_link, SDEV_DB2, ("open complete\n"));
591 	return (0);
592 
593 bad:
594 	st_unmount(st, NOEJECT);
595 	sc_link->flags &= ~SDEV_OPEN;
596 	return (error);
597 }
598 
599 /*
600  * close the device.. only called if we are the LAST
601  * occurence of an open device
602  */
603 int
604 stclose(dev, flags, mode, p)
605 	dev_t dev;
606 	int flags;
607 	int mode;
608 	struct proc *p;
609 {
610 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
611 
612 	SC_DEBUG(st->sc_link, SDEV_DB1, ("closing\n"));
613 	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
614 		st_write_filemarks(st, 1, 0);
615 	switch (STMODE(dev)) {
616 	case 0:
617 	case 3:		/* for now */
618 		st_unmount(st, NOEJECT);
619 		break;
620 	case 1:
621 		/* leave mounted unless media seems to have been removed */
622 		if (!(st->sc_link->flags & SDEV_MEDIA_LOADED))
623 			st_unmount(st, NOEJECT);
624 		break;
625 	case 2:
626 		st_unmount(st, EJECT);
627 		break;
628 	}
629 	st->sc_link->flags &= ~SDEV_OPEN;
630 
631 	return (0);
632 }
633 
634 /*
635  * Start a new mount session.
636  * Copy in all the default parameters from the selected device mode.
637  * and try guess any that seem to be defaulted.
638  */
639 int
640 st_mount_tape(dev, flags)
641 	dev_t dev;
642 	int flags;
643 {
644 	int unit;
645 	u_int mode, dsty;
646 	struct st_softc *st;
647 	struct scsipi_link *sc_link;
648 	int error = 0;
649 
650 	unit = STUNIT(dev);
651 	mode = STMODE(dev);
652 	dsty = STDSTY(dev);
653 	st = st_cd.cd_devs[unit];
654 	sc_link = st->sc_link;
655 
656 	if (st->flags & ST_MOUNTED)
657 		return (0);
658 
659 	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
660 	st->flags |= ST_NEW_MOUNT;
661 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
662 	/*
663 	 * If the media is new, then make sure we give it a chance to
664 	 * to do a 'load' instruction.  (We assume it is new.)
665 	 */
666 	if ((error = st_load(st, LD_LOAD, 0)) != 0)
667 		return (error);
668 	/*
669 	 * Throw another dummy instruction to catch
670 	 * 'Unit attention' errors. Some drives appear to give
671 	 * these after doing a Load instruction.
672 	 * (noteably some DAT drives)
673 	 */
674 	scsipi_test_unit_ready(sc_link, SCSI_SILENT);	/* XXX */
675 
676 	/*
677 	 * Some devices can't tell you much until they have been
678 	 * asked to look at the media. This quirk does this.
679 	 */
680 	if (st->quirks & ST_Q_SENSE_HELP)
681 		if ((error = st_touch_tape(st)) != 0)
682 			return (error);
683 	/*
684 	 * Load the physical device parameters
685 	 * loads: blkmin, blkmax
686 	 */
687 	if ((error = st_read_block_limits(st, 0)) != 0)
688 		return (error);
689 	/*
690 	 * Load the media dependent parameters
691 	 * includes: media_blksize,media_density,numblks
692 	 * As we have a tape in, it should be reflected here.
693 	 * If not you may need the "quirk" above.
694 	 */
695 	if ((error = st_mode_sense(st, 0)) != 0)
696 		return (error);
697 	/*
698 	 * If we have gained a permanent density from somewhere,
699 	 * then use it in preference to the one supplied by
700 	 * default by the driver.
701 	 */
702 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
703 		st->density = st->modes[dsty].density;
704 	else
705 		st->density = st->media_density;
706 	/*
707 	 * If we have gained a permanent blocksize
708 	 * then use it in preference to the one supplied by
709 	 * default by the driver.
710 	 */
711 	st->flags &= ~ST_FIXEDBLOCKS;
712 	if (st->modeflags[dsty] &
713 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
714 		st->blksize = st->modes[dsty].blksize;
715 		if (st->blksize)
716 			st->flags |= ST_FIXEDBLOCKS;
717 	} else {
718 		if ((error = st_decide_mode(st, FALSE)) != 0)
719 			return (error);
720 	}
721 	if ((error = st_mode_select(st, 0)) != 0) {
722 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
723 		return (error);
724 	}
725 	scsipi_prevent(sc_link, PR_PREVENT,
726 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
727 	st->flags &= ~ST_NEW_MOUNT;
728 	st->flags |= ST_MOUNTED;
729 	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
730 
731 	return (0);
732 }
733 
734 /*
735  * End the present mount session.
736  * Rewind, and optionally eject the tape.
737  * Reset various flags to indicate that all new
738  * operations require another mount operation
739  */
740 void
741 st_unmount(st, eject)
742 	struct st_softc *st;
743 	boolean eject;
744 {
745 	struct scsipi_link *sc_link = st->sc_link;
746 	int nmarks;
747 
748 	if (!(st->flags & ST_MOUNTED))
749 		return;
750 	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
751 	st_check_eod(st, FALSE, &nmarks, SCSI_IGNORE_NOT_READY);
752 	st_rewind(st, 0, SCSI_IGNORE_NOT_READY);
753 	scsipi_prevent(sc_link, PR_ALLOW,
754 	    SCSI_IGNORE_ILLEGAL_REQUEST | SCSI_IGNORE_NOT_READY);
755 	if (eject)
756 		st_load(st, LD_UNLOAD, SCSI_IGNORE_NOT_READY);
757 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
758 	sc_link->flags &= ~SDEV_MEDIA_LOADED;
759 }
760 
761 /*
762  * Given all we know about the device, media, mode, 'quirks' and
763  * initial operation, make a decision as to how we should be set
764  * to run (regarding blocking and EOD marks)
765  */
766 int
767 st_decide_mode(st, first_read)
768 	struct st_softc *st;
769 	boolean	first_read;
770 {
771 #ifdef SCSIDEBUG
772 	struct scsipi_link *sc_link = st->sc_link;
773 #endif
774 
775 	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
776 
777 	/*
778 	 * If the drive can only handle fixed-length blocks and only at
779 	 * one size, perhaps we should just do that.
780 	 */
781 	if (st->blkmin && (st->blkmin == st->blkmax)) {
782 		st->flags |= ST_FIXEDBLOCKS;
783 		st->blksize = st->blkmin;
784 		SC_DEBUG(sc_link, SDEV_DB3,
785 		    ("blkmin == blkmax of %d\n", st->blkmin));
786 		goto done;
787 	}
788 	/*
789 	 * If the tape density mandates (or even suggests) use of fixed
790 	 * or variable-length blocks, comply.
791 	 */
792 	switch (st->density) {
793 	case HALFINCH_800:
794 	case HALFINCH_1600:
795 	case HALFINCH_6250:
796 	case DDS:
797 		st->flags &= ~ST_FIXEDBLOCKS;
798 		st->blksize = 0;
799 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
800 		goto done;
801 	case QIC_11:
802 	case QIC_24:
803 	case QIC_120:
804 	case QIC_150:
805 	case QIC_525:
806 	case QIC_1320:
807 		st->flags |= ST_FIXEDBLOCKS;
808 		if (st->media_blksize > 0)
809 			st->blksize = st->media_blksize;
810 		else
811 			st->blksize = DEF_FIXED_BSIZE;
812 		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
813 		goto done;
814 	}
815 	/*
816 	 * If we're about to read the tape, perhaps we should choose
817 	 * fixed or variable-length blocks and block size according to
818 	 * what the drive found on the tape.
819 	 */
820 	if (first_read &&
821 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
822 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
823 	    (st->media_blksize == 1024))) {
824 		if (st->media_blksize > 0)
825 			st->flags |= ST_FIXEDBLOCKS;
826 		else
827 			st->flags &= ~ST_FIXEDBLOCKS;
828 		st->blksize = st->media_blksize;
829 		SC_DEBUG(sc_link, SDEV_DB3,
830 		    ("Used media_blksize of %d\n", st->media_blksize));
831 		goto done;
832 	}
833 	/*
834 	 * We're getting no hints from any direction.  Choose variable-
835 	 * length blocks arbitrarily.
836 	 */
837 	st->flags &= ~ST_FIXEDBLOCKS;
838 	st->blksize = 0;
839 	SC_DEBUG(sc_link, SDEV_DB3,
840 	    ("Give up and default to variable mode\n"));
841 
842 done:
843 	/*
844 	 * Decide whether or not to write two file marks to signify end-
845 	 * of-data.  Make the decision as a function of density.  If
846 	 * the decision is not to use a second file mark, the SCSI BLANK
847 	 * CHECK condition code will be recognized as end-of-data when
848 	 * first read.
849 	 * (I think this should be a by-product of fixed/variable..julian)
850 	 */
851 	switch (st->density) {
852 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
853 	case QIC_11:
854 	case QIC_24:
855 	case QIC_120:
856 	case QIC_150:
857 	case QIC_525:
858 	case QIC_1320:
859 		st->flags &= ~ST_2FM_AT_EOD;
860 		break;
861 	default:
862 		st->flags |= ST_2FM_AT_EOD;
863 	}
864 	return (0);
865 }
866 
867 /*
868  * Actually translate the requested transfer into
869  * one the physical driver can understand
870  * The transfer is described by a buf and will include
871  * only one physical transfer.
872  */
873 void
874 ststrategy(bp)
875 	struct buf *bp;
876 {
877 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
878 	struct buf *dp;
879 	int s;
880 
881 	SC_DEBUG(st->sc_link, SDEV_DB1,
882 	    ("ststrategy %ld bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
883 	/*
884 	 * If it's a null transfer, return immediatly
885 	 */
886 	if (bp->b_bcount == 0)
887 		goto done;
888 	/*
889 	 * Odd sized request on fixed drives are verboten
890 	 */
891 	if (st->flags & ST_FIXEDBLOCKS) {
892 		if (bp->b_bcount % st->blksize) {
893 			printf("%s: bad request, must be multiple of %d\n",
894 			    st->sc_dev.dv_xname, st->blksize);
895 			bp->b_error = EIO;
896 			goto bad;
897 		}
898 	}
899 	/*
900 	 * as are out-of-range requests on variable drives.
901 	 */
902 	else if (bp->b_bcount < st->blkmin ||
903 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
904 		printf("%s: bad request, must be between %d and %d\n",
905 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
906 		bp->b_error = EIO;
907 		goto bad;
908 	}
909 	s = splbio();
910 
911 	/*
912 	 * Place it in the queue of activities for this tape
913 	 * at the end (a bit silly because we only have on user..
914 	 * (but it could fork()))
915 	 */
916 	dp = &st->buf_queue;
917 	bp->b_actf = NULL;
918 	bp->b_actb = dp->b_actb;
919 	*dp->b_actb = bp;
920 	dp->b_actb = &bp->b_actf;
921 
922 	/*
923 	 * Tell the device to get going on the transfer if it's
924 	 * not doing anything, otherwise just wait for completion
925 	 * (All a bit silly if we're only allowing 1 open but..)
926 	 */
927 	ststart(st);
928 
929 	splx(s);
930 	return;
931 bad:
932 	bp->b_flags |= B_ERROR;
933 done:
934 	/*
935 	 * Correctly set the buf to indicate a completed xfer
936 	 */
937 	bp->b_resid = bp->b_bcount;
938 	biodone(bp);
939 	return;
940 }
941 
942 /*
943  * ststart looks to see if there is a buf waiting for the device
944  * and that the device is not already busy. If both are true,
945  * It dequeues the buf and creates a scsi command to perform the
946  * transfer required. The transfer request will call scsipi_done
947  * on completion, which will in turn call this routine again
948  * so that the next queued transfer is performed.
949  * The bufs are queued by the strategy routine (ststrategy)
950  *
951  * This routine is also called after other non-queued requests
952  * have been made of the scsi driver, to ensure that the queue
953  * continues to be drained.
954  * ststart() is called at splbio
955  */
956 void
957 ststart(v)
958 	void *v;
959 {
960 	struct st_softc *st = v;
961 	struct scsipi_link *sc_link = st->sc_link;
962 	register struct buf *bp, *dp;
963 	struct scsi_rw_tape cmd;
964 	int flags;
965 
966 	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
967 	/*
968 	 * See if there is a buf to do and we are not already
969 	 * doing one
970 	 */
971 	while (sc_link->openings > 0) {
972 		/* if a special awaits, let it proceed first */
973 		if (sc_link->flags & SDEV_WAITING) {
974 			sc_link->flags &= ~SDEV_WAITING;
975 			wakeup((caddr_t)sc_link);
976 			return;
977 		}
978 
979 		dp = &st->buf_queue;
980 		if ((bp = dp->b_actf) == NULL)
981 			return;
982 		if ((dp = bp->b_actf) != NULL)
983 			dp->b_actb = bp->b_actb;
984 		else
985 			st->buf_queue.b_actb = bp->b_actb;
986 		*bp->b_actb = dp;
987 
988 		/*
989 		 * if the device has been unmounted byt the user
990 		 * then throw away all requests until done
991 		 */
992 		if (!(st->flags & ST_MOUNTED) ||
993 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
994 			/* make sure that one implies the other.. */
995 			sc_link->flags &= ~SDEV_MEDIA_LOADED;
996 			bp->b_flags |= B_ERROR;
997 			bp->b_error = EIO;
998 			bp->b_resid = bp->b_bcount;
999 			biodone(bp);
1000 			continue;
1001 		}
1002 		/*
1003 		 * only FIXEDBLOCK devices have pending operations
1004 		 */
1005 		if (st->flags & ST_FIXEDBLOCKS) {
1006 			/*
1007 			 * If we are at a filemark but have not reported it yet
1008 			 * then we should report it now
1009 			 */
1010 			if (st->flags & ST_AT_FILEMARK) {
1011 				if ((bp->b_flags & B_READ) == B_WRITE) {
1012 					/*
1013 					 * Handling of ST_AT_FILEMARK in
1014 					 * st_space will fill in the right file
1015 					 * mark count.
1016 					 * Back up over filemark
1017 					 */
1018 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1019 						bp->b_flags |= B_ERROR;
1020 						bp->b_error = EIO;
1021 						biodone(bp);
1022 						continue;
1023 					}
1024 				} else {
1025 					bp->b_resid = bp->b_bcount;
1026 					bp->b_error = 0;
1027 					bp->b_flags &= ~B_ERROR;
1028 					st->flags &= ~ST_AT_FILEMARK;
1029 					biodone(bp);
1030 					continue;	/* seek more work */
1031 				}
1032 			}
1033 			/*
1034 			 * If we are at EIO (e.g. EOM) but have not reported it
1035 			 * yet then we should report it now
1036 			 */
1037 			if (st->flags & ST_EIO_PENDING) {
1038 				bp->b_resid = bp->b_bcount;
1039 				bp->b_error = EIO;
1040 				bp->b_flags |= B_ERROR;
1041 				st->flags &= ~ST_EIO_PENDING;
1042 				biodone(bp);
1043 				continue;	/* seek more work */
1044 			}
1045 		}
1046 
1047 		/*
1048 		 *  Fill out the scsi command
1049 		 */
1050 		bzero(&cmd, sizeof(cmd));
1051 		if ((bp->b_flags & B_READ) == B_WRITE) {
1052 			cmd.opcode = WRITE;
1053 			st->flags &= ~ST_FM_WRITTEN;
1054 			st->flags |= ST_WRITTEN;
1055 			flags = SCSI_DATA_OUT;
1056 		} else {
1057 			cmd.opcode = READ;
1058 			flags = SCSI_DATA_IN;
1059 		}
1060 
1061 		/*
1062 		 * Handle "fixed-block-mode" tape drives by using the
1063 		 * block count instead of the length.
1064 		 */
1065 		if (st->flags & ST_FIXEDBLOCKS) {
1066 			cmd.byte2 |= SRW_FIXED;
1067 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1068 		} else
1069 			_lto3b(bp->b_bcount, cmd.len);
1070 
1071 		/*
1072 		 * go ask the adapter to do all this for us
1073 		 */
1074 		if (scsipi_command(sc_link,
1075 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1076 		    (u_char *)bp->b_data, bp->b_bcount,
1077 		    0, 100000, bp, flags | SCSI_NOSLEEP))
1078 			printf("%s: not queued\n", st->sc_dev.dv_xname);
1079 	} /* go back and see if we can cram more work in.. */
1080 }
1081 
1082 #if NRND > 0
1083 void
1084 stdone(xs)
1085 	struct scsipi_xfer *xs;
1086 {
1087 	struct st_softc *st = xs->sc_link->device_softc;
1088 
1089 	if (xs->bp != NULL)
1090 		rnd_add_uint32(&st->rnd_source, xs->bp->b_blkno);
1091 }
1092 #endif
1093 
1094 int
1095 stread(dev, uio, iomode)
1096 	dev_t dev;
1097 	struct uio *uio;
1098 	int iomode;
1099 {
1100 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1101 
1102 	return (physio(ststrategy, NULL, dev, B_READ,
1103 	    st->sc_link->adapter->scsipi_minphys, uio));
1104 }
1105 
1106 int
1107 stwrite(dev, uio, iomode)
1108 	dev_t dev;
1109 	struct uio *uio;
1110 	int iomode;
1111 {
1112 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1113 
1114 	return (physio(ststrategy, NULL, dev, B_WRITE,
1115 	    st->sc_link->adapter->scsipi_minphys, uio));
1116 }
1117 
1118 /*
1119  * Perform special action on behalf of the user;
1120  * knows about the internals of this device
1121  */
1122 int
1123 stioctl(dev, cmd, arg, flag, p)
1124 	dev_t dev;
1125 	u_long cmd;
1126 	caddr_t arg;
1127 	int flag;
1128 	struct proc *p;
1129 {
1130 	int error = 0;
1131 	int unit;
1132 	int number, nmarks, dsty;
1133 	int flags;
1134 	struct st_softc *st;
1135 	int hold_blksize;
1136 	u_int8_t hold_density;
1137 	struct mtop *mt = (struct mtop *) arg;
1138 
1139 	/*
1140 	 * Find the device that the user is talking about
1141 	 */
1142 	flags = 0;		/* give error messages, act on errors etc. */
1143 	unit = STUNIT(dev);
1144 	dsty = STDSTY(dev);
1145 	st = st_cd.cd_devs[unit];
1146 	hold_blksize = st->blksize;
1147 	hold_density = st->density;
1148 
1149 	switch ((u_int) cmd) {
1150 
1151 	case MTIOCGET: {
1152 		struct mtget *g = (struct mtget *) arg;
1153 
1154 		SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
1155 		bzero(g, sizeof(struct mtget));
1156 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1157 		g->mt_blksiz = st->blksize;
1158 		g->mt_density = st->density;
1159 		g->mt_mblksiz[0] = st->modes[0].blksize;
1160 		g->mt_mblksiz[1] = st->modes[1].blksize;
1161 		g->mt_mblksiz[2] = st->modes[2].blksize;
1162 		g->mt_mblksiz[3] = st->modes[3].blksize;
1163 		g->mt_mdensity[0] = st->modes[0].density;
1164 		g->mt_mdensity[1] = st->modes[1].density;
1165 		g->mt_mdensity[2] = st->modes[2].density;
1166 		g->mt_mdensity[3] = st->modes[3].density;
1167 		break;
1168 	}
1169 	case MTIOCTOP: {
1170 
1171 		SC_DEBUG(st->sc_link, SDEV_DB1,
1172 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1173 			mt->mt_count));
1174 
1175 		/* compat: in U*x it is a short */
1176 		number = mt->mt_count;
1177 		switch ((short) (mt->mt_op)) {
1178 		case MTWEOF:	/* write an end-of-file record */
1179 			error = st_write_filemarks(st, number, flags);
1180 			break;
1181 		case MTBSF:	/* backward space file */
1182 			number = -number;
1183 		case MTFSF:	/* forward space file */
1184 			error = st_check_eod(st, FALSE, &nmarks, flags);
1185 			if (!error)
1186 				error = st_space(st, number - nmarks,
1187 				    SP_FILEMARKS, flags);
1188 			break;
1189 		case MTBSR:	/* backward space record */
1190 			number = -number;
1191 		case MTFSR:	/* forward space record */
1192 			error = st_check_eod(st, TRUE, &nmarks, flags);
1193 			if (!error)
1194 				error = st_space(st, number, SP_BLKS, flags);
1195 			break;
1196 		case MTREW:	/* rewind */
1197 			error = st_rewind(st, 0, flags);
1198 			break;
1199 		case MTOFFL:	/* rewind and put the drive offline */
1200 			st_unmount(st, EJECT);
1201 			break;
1202 		case MTNOP:	/* no operation, sets status only */
1203 			break;
1204 		case MTRETEN:	/* retension the tape */
1205 			error = st_load(st, LD_RETENSION, flags);
1206 			if (!error)
1207 				error = st_load(st, LD_LOAD, flags);
1208 			break;
1209 		case MTEOM:	/* forward space to end of media */
1210 			error = st_check_eod(st, FALSE, &nmarks, flags);
1211 			if (!error)
1212 				error = st_space(st, 1, SP_EOM, flags);
1213 			break;
1214 		case MTCACHE:	/* enable controller cache */
1215 			st->flags &= ~ST_DONTBUFFER;
1216 			goto try_new_value;
1217 		case MTNOCACHE:	/* disable controller cache */
1218 			st->flags |= ST_DONTBUFFER;
1219 			goto try_new_value;
1220 		case MTERASE:	/* erase volume */
1221 			error = st_erase(st, number, flags);
1222 			break;
1223 		case MTSETBSIZ:	/* Set block size for device */
1224 #ifdef	NOTYET
1225 			if (!(st->flags & ST_NEW_MOUNT)) {
1226 				uprintf("re-mount tape before changing blocksize");
1227 				error = EINVAL;
1228 				break;
1229 			}
1230 #endif
1231 			if (number == 0)
1232 				st->flags &= ~ST_FIXEDBLOCKS;
1233 			else {
1234 				if ((st->blkmin || st->blkmax) &&
1235 				    (number < st->blkmin ||
1236 				    number > st->blkmax)) {
1237 					error = EINVAL;
1238 					break;
1239 				}
1240 				st->flags |= ST_FIXEDBLOCKS;
1241 			}
1242 			st->blksize = number;
1243 			st->flags |= ST_BLOCK_SET;	/*XXX */
1244 			goto try_new_value;
1245 
1246 		case MTSETDNSTY:	/* Set density for device and mode */
1247 			if (number > SCSI_2_MAX_DENSITY_CODE) {
1248 				error = EINVAL;
1249 				break;
1250 			} else
1251 				st->density = number;
1252 			goto try_new_value;
1253 
1254 		case MTCMPRESS:
1255 			error = st_cmprss(st, number);
1256 			break;
1257 
1258 		default:
1259 			error = EINVAL;
1260 		}
1261 		break;
1262 	}
1263 	case MTIOCIEOT:
1264 	case MTIOCEEOT:
1265 		break;
1266 
1267 	case MTIOCRDSPOS:
1268 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1269 		break;
1270 
1271 	case MTIOCRDHPOS:
1272 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1273 		break;
1274 
1275 	case MTIOCSLOCATE:
1276 		error = st_setpos(st, 0, (u_int32_t *) arg);
1277 		break;
1278 
1279 	case MTIOCHLOCATE:
1280 		error = st_setpos(st, 1, (u_int32_t *) arg);
1281 		break;
1282 
1283 	default:
1284 		if (STMODE(dev) == CTLMODE)
1285 			error = scsipi_do_ioctl(st->sc_link, dev, cmd, arg,
1286 			    flag, p);
1287 		else
1288 			error = ENOTTY;
1289 		break;
1290 	}
1291 	return (error);
1292 /*-----------------------------*/
1293 try_new_value:
1294 	/*
1295 	 * Check that the mode being asked for is aggreeable to the
1296 	 * drive. If not, put it back the way it was.
1297 	 */
1298 	if ((error = st_mode_select(st, 0)) != 0) {/* put it back as it was */
1299 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1300 		st->density = hold_density;
1301 		st->blksize = hold_blksize;
1302 		if (st->blksize)
1303 			st->flags |= ST_FIXEDBLOCKS;
1304 		else
1305 			st->flags &= ~ST_FIXEDBLOCKS;
1306 		return (error);
1307 	}
1308 	/*
1309 	 * As the drive liked it, if we are setting a new default,
1310 	 * set it into the structures as such.
1311 	 *
1312 	 * The means for deciding this are not finalised yet
1313 	 */
1314 	if (STMODE(dev) == 0x03) {
1315 		/* special mode */
1316 		/* XXX */
1317 		switch ((short) (mt->mt_op)) {
1318 		case MTSETBSIZ:
1319 			st->modes[dsty].blksize = st->blksize;
1320 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1321 			break;
1322 		case MTSETDNSTY:
1323 			st->modes[dsty].density = st->density;
1324 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1325 			break;
1326 		}
1327 	}
1328 	return (0);
1329 }
1330 
1331 /*
1332  * Do a synchronous read.
1333  */
1334 int
1335 st_read(st, buf, size, flags)
1336 	struct st_softc *st;
1337 	int size;
1338 	int flags;
1339 	char *buf;
1340 {
1341 	struct scsi_rw_tape cmd;
1342 
1343 	/*
1344 	 * If it's a null transfer, return immediatly
1345 	 */
1346 	if (size == 0)
1347 		return (0);
1348 	bzero(&cmd, sizeof(cmd));
1349 	cmd.opcode = READ;
1350 	if (st->flags & ST_FIXEDBLOCKS) {
1351 		cmd.byte2 |= SRW_FIXED;
1352 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1353 		    cmd.len);
1354 	} else
1355 		_lto3b(size, cmd.len);
1356 	return (scsipi_command(st->sc_link,
1357 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1358 	    (u_char *)buf, size, 0, 100000, NULL, flags | SCSI_DATA_IN));
1359 }
1360 
1361 /*
1362  * Ask the drive what it's min and max blk sizes are.
1363  */
1364 int
1365 st_read_block_limits(st, flags)
1366 	struct st_softc *st;
1367 	int flags;
1368 {
1369 	struct scsi_block_limits cmd;
1370 	struct scsi_block_limits_data block_limits;
1371 	struct scsipi_link *sc_link = st->sc_link;
1372 	int error;
1373 
1374 	/*
1375 	 * First check if we have it all loaded
1376 	 */
1377 	if ((sc_link->flags & SDEV_MEDIA_LOADED))
1378 		return (0);
1379 
1380 	/*
1381 	 * do a 'Read Block Limits'
1382 	 */
1383 	bzero(&cmd, sizeof(cmd));
1384 	cmd.opcode = READ_BLOCK_LIMITS;
1385 
1386 	/*
1387 	 * do the command, update the global values
1388 	 */
1389 	error = scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1390 	    sizeof(cmd), (u_char *)&block_limits, sizeof(block_limits),
1391 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1392 	if (error)
1393 		return (error);
1394 
1395 	st->blkmin = _2btol(block_limits.min_length);
1396 	st->blkmax = _3btol(block_limits.max_length);
1397 
1398 	SC_DEBUG(sc_link, SDEV_DB3,
1399 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
1400 	return (0);
1401 }
1402 
1403 /*
1404  * Get the scsi driver to send a full inquiry to the
1405  * device and use the results to fill out the global
1406  * parameter structure.
1407  *
1408  * called from:
1409  * attach
1410  * open
1411  * ioctl (to reset original blksize)
1412  */
1413 int
1414 st_mode_sense(st, flags)
1415 	struct st_softc *st;
1416 	int flags;
1417 {
1418 	u_int scsipi_sense_len;
1419 	int error;
1420 	struct scsi_mode_sense cmd;
1421 	struct scsipi_sense {
1422 		struct scsi_mode_header header;
1423 		struct scsi_blk_desc blk_desc;
1424 		u_char sense_data[MAX_PAGE_0_SIZE];
1425 	} scsipi_sense;
1426 	struct scsipi_link *sc_link = st->sc_link;
1427 
1428 	scsipi_sense_len = 12 + st->page_0_size;
1429 
1430 	/*
1431 	 * Set up a mode sense
1432 	 */
1433 	bzero(&cmd, sizeof(cmd));
1434 	cmd.opcode = SCSI_MODE_SENSE;
1435 	cmd.length = scsipi_sense_len;
1436 
1437 	/*
1438 	 * do the command, but we don't need the results
1439 	 * just print them for our interest's sake, if asked,
1440 	 * or if we need it as a template for the mode select
1441 	 * store it away.
1442 	 */
1443 	error = scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1444 	    sizeof(cmd), (u_char *)&scsipi_sense, scsipi_sense_len,
1445 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1446 	if (error)
1447 		return (error);
1448 
1449 	st->numblks = _3btol(scsipi_sense.blk_desc.nblocks);
1450 	st->media_blksize = _3btol(scsipi_sense.blk_desc.blklen);
1451 	st->media_density = scsipi_sense.blk_desc.density;
1452 	if (scsipi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
1453 		st->flags |= ST_READONLY;
1454 	SC_DEBUG(sc_link, SDEV_DB3,
1455 	    ("density code 0x%x, %d-byte blocks, write-%s, ",
1456 	    st->media_density, st->media_blksize,
1457 	    st->flags & ST_READONLY ? "protected" : "enabled"));
1458 	SC_DEBUG(sc_link, SDEV_DB3,
1459 	    ("%sbuffered\n",
1460 	    scsipi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
1461 	if (st->page_0_size)
1462 		bcopy(scsipi_sense.sense_data, st->sense_data,
1463 		    st->page_0_size);
1464 	sc_link->flags |= SDEV_MEDIA_LOADED;
1465 	return (0);
1466 }
1467 
1468 /*
1469  * Send a filled out parameter structure to the drive to
1470  * set it into the desire modes etc.
1471  */
1472 int
1473 st_mode_select(st, flags)
1474 	struct st_softc *st;
1475 	int flags;
1476 {
1477 	u_int scsi_select_len;
1478 	struct scsi_mode_select cmd;
1479 	struct scsi_select {
1480 		struct scsi_mode_header header;
1481 		struct scsi_blk_desc blk_desc;
1482 		u_char sense_data[MAX_PAGE_0_SIZE];
1483 	} scsi_select;
1484 	struct scsipi_link *sc_link = st->sc_link;
1485 
1486 	scsi_select_len = 12 + st->page_0_size;
1487 
1488 	/*
1489 	 * This quirk deals with drives that have only one valid mode
1490 	 * and think this gives them license to reject all mode selects,
1491 	 * even if the selected mode is the one that is supported.
1492 	 */
1493 	if (st->quirks & ST_Q_UNIMODAL) {
1494 		SC_DEBUG(sc_link, SDEV_DB3,
1495 		    ("not setting density 0x%x blksize 0x%x\n",
1496 		    st->density, st->blksize));
1497 		return (0);
1498 	}
1499 
1500 	/*
1501 	 * Set up for a mode select
1502 	 */
1503 	bzero(&cmd, sizeof(cmd));
1504 	cmd.opcode = SCSI_MODE_SELECT;
1505 	cmd.length = scsi_select_len;
1506 
1507 	bzero(&scsi_select, scsi_select_len);
1508 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
1509 	scsi_select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
1510 	scsi_select.blk_desc.density = st->density;
1511 	if (st->flags & ST_DONTBUFFER)
1512 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
1513 	else
1514 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
1515 	if (st->flags & ST_FIXEDBLOCKS)
1516 		_lto3b(st->blksize, scsi_select.blk_desc.blklen);
1517 	if (st->page_0_size)
1518 		bcopy(st->sense_data, scsi_select.sense_data, st->page_0_size);
1519 
1520 	/*
1521 	 * do the command
1522 	 */
1523 	return (scsipi_command(sc_link, (struct scsipi_generic *)&cmd,
1524 	    sizeof(cmd), (u_char *)&scsi_select, scsi_select_len,
1525 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT));
1526 }
1527 
1528 int
1529 st_cmprss(st, onoff)
1530 	struct st_softc *st;
1531 	int onoff;
1532 {
1533 	u_int scsi_dlen;
1534 	struct scsi_mode_select mcmd;
1535 	struct scsi_mode_sense scmd;
1536 	struct scsi_select {
1537 		struct scsi_mode_header header;
1538 		struct scsi_blk_desc blk_desc;
1539 		u_char pdata[max(sizeof(struct scsi_tape_dev_conf_page),
1540 		    sizeof(struct scsi_tape_dev_compression_page))];
1541 	} scsi_pdata;
1542 	struct scsi_tape_dev_conf_page *ptr;
1543 	struct scsi_tape_dev_compression_page *cptr;
1544 	struct scsipi_link *sc_link = st->sc_link;
1545 	int error, ison, flags;
1546 
1547 	scsi_dlen = sizeof(scsi_pdata);
1548 	bzero(&scsi_pdata, scsi_dlen);
1549 
1550 	/*
1551 	 * Set up for a mode sense.
1552 	 * Do DATA COMPRESSION page first.
1553 	 */
1554 	bzero(&scmd, sizeof(scmd));
1555 	scmd.opcode = SCSI_MODE_SENSE;
1556 	scmd.page = SMS_PAGE_CTRL_CURRENT | 0xf;
1557 	scmd.length = scsi_dlen;
1558 
1559 	flags = SCSI_SILENT;
1560 
1561 	/*
1562 	 * Do the MODE SENSE command...
1563 	 */
1564 again:
1565 	error = scsipi_command(sc_link,
1566 	    (struct scsipi_generic *)&scmd, sizeof(scmd),
1567 	    (u_char *)&scsi_pdata, scsi_dlen,
1568 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_IN);
1569 
1570 	if (error) {
1571 		if (scmd.byte2 != SMS_DBD) {
1572 			scmd.byte2 = SMS_DBD;
1573 			goto again;
1574 		}
1575 		return (error);
1576 	}
1577 
1578 	if (scsi_pdata.header.blk_desc_len)
1579 		ptr = (struct scsi_tape_dev_conf_page *) scsi_pdata.pdata;
1580 	else
1581 		ptr = (struct scsi_tape_dev_conf_page *) &scsi_pdata.blk_desc;
1582 
1583 	if ((scmd.page & SMS_PAGE_CODE) == 0xf) {
1584 		cptr = (struct scsi_tape_dev_compression_page *) ptr;
1585 		ison = (cptr->dce_dcc & DCP_DCE) != 0;
1586 		if (onoff)
1587 			cptr->dce_dcc |= DCP_DCE;
1588 		else
1589 			cptr->dce_dcc &= ~DCP_DCE;
1590 		cptr->pagecode &= ~0x80;
1591 	} else {
1592 		ison =  (ptr->sel_comp_alg != 0);
1593 		if (onoff)
1594 			ptr->sel_comp_alg = 1;
1595 		else
1596 			ptr->sel_comp_alg = 0;
1597 		ptr->pagecode &= ~0x80;
1598 	}
1599 	onoff = onoff ? 1 : 0;
1600 	/*
1601 	 * There might be a virtue in actually doing the MODE SELECTS,
1602 	 * but let's not clog the bus over it.
1603 	 */
1604 	if (onoff == ison)
1605 		return (0);
1606 
1607 	/*
1608 	 * Set up for a mode select
1609 	 */
1610 
1611 	scsi_pdata.header.data_length = 0;
1612 	scsi_pdata.header.medium_type = 0;
1613 	if ((st->flags & ST_DONTBUFFER) == 0)
1614 		scsi_pdata.header.dev_spec = SMH_DSP_BUFF_MODE_ON;
1615 	else
1616 		scsi_pdata.header.dev_spec = 0;
1617 
1618 	bzero(&mcmd, sizeof(mcmd));
1619 	mcmd.opcode = SCSI_MODE_SELECT;
1620 	mcmd.byte2 = SMS_PF;
1621 	mcmd.length = scsi_dlen;
1622 	if (scsi_pdata.header.blk_desc_len) {
1623 		scsi_pdata.blk_desc.density = 0;
1624 		scsi_pdata.blk_desc.nblocks[0] = 0;
1625 		scsi_pdata.blk_desc.nblocks[1] = 0;
1626 		scsi_pdata.blk_desc.nblocks[2] = 0;
1627 	}
1628 
1629 	/*
1630 	 * Do the command
1631 	 */
1632 	error = scsipi_command(sc_link,
1633 	    (struct scsipi_generic *)&mcmd, sizeof(mcmd),
1634 	    (u_char *)&scsi_pdata, scsi_dlen,
1635 	    ST_RETRIES, 5000, NULL, flags | SCSI_DATA_OUT);
1636 
1637 	if (error && (scmd.page & SMS_PAGE_CODE) == 0xf) {
1638 		/*
1639 		 * Try DEVICE CONFIGURATION page.
1640 		 */
1641 		scmd.page = SMS_PAGE_CTRL_CURRENT | 0x10;
1642 		goto again;
1643 	}
1644 	return (error);
1645 }
1646 /*
1647  * issue an erase command
1648  */
1649 int
1650 st_erase(st, full, flags)
1651 	struct st_softc *st;
1652 	int full, flags;
1653 {
1654 	struct scsi_erase cmd;
1655 
1656 	/*
1657 	 * Full erase means set LONG bit in erase command, which asks
1658 	 * the drive to erase the entire unit.  Without this bit, we're
1659 	 * asking the drive to write an erase gap.
1660 	 */
1661 	bzero(&cmd, sizeof(cmd));
1662 	cmd.opcode = ERASE;
1663 	if (full)
1664 		cmd.byte2 = SE_IMMED|SE_LONG;
1665 	else
1666 		cmd.byte2 = SE_IMMED;
1667 
1668 	/*
1669 	 * XXX We always do this asynchronously, for now.  How long should
1670 	 * we wait if we want to (eventually) to it synchronously?
1671 	 */
1672 	return (scsipi_command(st->sc_link,
1673 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1674 	    0, 0, ST_RETRIES, 5000, NULL, flags));
1675 }
1676 
1677 /*
1678  * skip N blocks/filemarks/seq filemarks/eom
1679  */
1680 int
1681 st_space(st, number, what, flags)
1682 	struct st_softc *st;
1683 	u_int what;
1684 	int flags;
1685 	int number;
1686 {
1687 	struct scsi_space cmd;
1688 	int error;
1689 
1690 	switch (what) {
1691 	case SP_BLKS:
1692 		if (st->flags & ST_PER_ACTION) {
1693 			if (number > 0) {
1694 				st->flags &= ~ST_PER_ACTION;
1695 				return (EIO);
1696 			} else if (number < 0) {
1697 				if (st->flags & ST_AT_FILEMARK) {
1698 					/*
1699 					 * Handling of ST_AT_FILEMARK
1700 					 * in st_space will fill in the
1701 					 * right file mark count.
1702 					 */
1703 					error = st_space(st, 0, SP_FILEMARKS,
1704 					    flags);
1705 					if (error)
1706 						return (error);
1707 				}
1708 				if (st->flags & ST_BLANK_READ) {
1709 					st->flags &= ~ST_BLANK_READ;
1710 					return (EIO);
1711 				}
1712 				st->flags &= ~ST_EIO_PENDING;
1713 			}
1714 		}
1715 		break;
1716 	case SP_FILEMARKS:
1717 		if (st->flags & ST_EIO_PENDING) {
1718 			if (number > 0) {
1719 				/* pretend we just discovered the error */
1720 				st->flags &= ~ST_EIO_PENDING;
1721 				return (EIO);
1722 			} else if (number < 0) {
1723 				/* back away from the error */
1724 				st->flags &= ~ST_EIO_PENDING;
1725 			}
1726 		}
1727 		if (st->flags & ST_AT_FILEMARK) {
1728 			st->flags &= ~ST_AT_FILEMARK;
1729 			number--;
1730 		}
1731 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1732 			/* back away from unwritten tape */
1733 			st->flags &= ~ST_BLANK_READ;
1734 			number++;	/* XXX dubious */
1735 		}
1736 		break;
1737 	case SP_EOM:
1738 		if (st->flags & ST_EIO_PENDING) {
1739 			/* pretend we just discovered the error */
1740 			st->flags &= ~ST_EIO_PENDING;
1741 			return (EIO);
1742 		}
1743 		if (st->flags & ST_AT_FILEMARK)
1744 			st->flags &= ~ST_AT_FILEMARK;
1745 		break;
1746 	}
1747 	if (number == 0)
1748 		return (0);
1749 
1750 	bzero(&cmd, sizeof(cmd));
1751 	cmd.opcode = SPACE;
1752 	cmd.byte2 = what;
1753 	_lto3b(number, cmd.number);
1754 
1755 	return (scsipi_command(st->sc_link,
1756 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1757 	    0, 0, 0, 1800000, NULL, flags));
1758 }
1759 
1760 /*
1761  * write N filemarks
1762  */
1763 int
1764 st_write_filemarks(st, number, flags)
1765 	struct st_softc *st;
1766 	int flags;
1767 	int number;
1768 {
1769 	struct scsi_write_filemarks cmd;
1770 
1771 	/*
1772 	 * It's hard to write a negative number of file marks.
1773 	 * Don't try.
1774 	 */
1775 	if (number < 0)
1776 		return (EINVAL);
1777 	switch (number) {
1778 	case 0:		/* really a command to sync the drive's buffers */
1779 		break;
1780 	case 1:
1781 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1782 			st->flags &= ~ST_WRITTEN;
1783 		else
1784 			st->flags |= ST_FM_WRITTEN;
1785 		st->flags &= ~ST_PER_ACTION;
1786 		break;
1787 	default:
1788 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1789 	}
1790 
1791 	bzero(&cmd, sizeof(cmd));
1792 	cmd.opcode = WRITE_FILEMARKS;
1793 	_lto3b(number, cmd.number);
1794 
1795 	return (scsipi_command(st->sc_link,
1796 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1797 	    0, 0, 0, 100000, NULL, flags));
1798 }
1799 
1800 /*
1801  * Make sure the right number of file marks is on tape if the
1802  * tape has been written.  If the position argument is true,
1803  * leave the tape positioned where it was originally.
1804  *
1805  * nmarks returns the number of marks to skip (or, if position
1806  * true, which were skipped) to get back original position.
1807  */
1808 int
1809 st_check_eod(st, position, nmarks, flags)
1810 	struct st_softc *st;
1811 	boolean position;
1812 	int *nmarks;
1813 	int flags;
1814 {
1815 	int error;
1816 
1817 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1818 	default:
1819 		*nmarks = 0;
1820 		return (0);
1821 	case ST_WRITTEN:
1822 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1823 		*nmarks = 1;
1824 		break;
1825 	case ST_WRITTEN | ST_2FM_AT_EOD:
1826 		*nmarks = 2;
1827 	}
1828 	error = st_write_filemarks(st, *nmarks, flags);
1829 	if (position && !error)
1830 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1831 	return (error);
1832 }
1833 
1834 /*
1835  * load/unload/retension
1836  */
1837 int
1838 st_load(st, type, flags)
1839 	struct st_softc *st;
1840 	u_int type;
1841 	int flags;
1842 {
1843 	struct scsi_load cmd;
1844 
1845 	if (type != LD_LOAD) {
1846 		int error;
1847 		int nmarks;
1848 
1849 		error = st_check_eod(st, FALSE, &nmarks, flags);
1850 		if (error)
1851 			return (error);
1852 	}
1853 	if (st->quirks & ST_Q_IGNORE_LOADS)
1854 		return (0);
1855 
1856 	bzero(&cmd, sizeof(cmd));
1857 	cmd.opcode = LOAD;
1858 	cmd.how = type;
1859 
1860 	return (scsipi_command(st->sc_link,
1861 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1862 	    0, 0, ST_RETRIES, 300000, NULL, flags));
1863 }
1864 
1865 /*
1866  *  Rewind the device
1867  */
1868 int
1869 st_rewind(st, immediate, flags)
1870 	struct st_softc *st;
1871 	u_int immediate;
1872 	int flags;
1873 {
1874 	struct scsi_rewind cmd;
1875 	int error;
1876 	int nmarks;
1877 
1878 	error = st_check_eod(st, FALSE, &nmarks, flags);
1879 	if (error)
1880 		return (error);
1881 	st->flags &= ~ST_PER_ACTION;
1882 
1883 	bzero(&cmd, sizeof(cmd));
1884 	cmd.opcode = REWIND;
1885 	cmd.byte2 = immediate;
1886 
1887 	return (scsipi_command(st->sc_link,
1888 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1889 	    0, 0, ST_RETRIES, immediate ? 5000 : 300000, NULL, flags));
1890 }
1891 
1892 int
1893 st_rdpos(st, hard, blkptr)
1894 	struct st_softc *st;
1895 	int hard;
1896 	u_int32_t *blkptr;
1897 {
1898 	int error;
1899 	u_int8_t posdata[20];
1900 	struct scsi_tape_read_position cmd;
1901 
1902 	/*
1903 	 * First flush any pending writes...
1904 	 */
1905 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1906 
1907 	/*
1908 	 * The latter case is for 'write protected' tapes
1909 	 * which are too stupid to recognize a zero count
1910 	 * for writing filemarks as a no-op.
1911 	 */
1912 	if (error != 0 && error != EACCES)
1913 		return (error);
1914 
1915 	bzero(&cmd, sizeof(cmd));
1916 	bzero(&posdata, sizeof(posdata));
1917 	cmd.opcode = READ_POSITION;
1918 	if (hard)
1919 		cmd.byte1 = 1;
1920 
1921 	error = scsipi_command(st->sc_link,
1922 	    (struct scsipi_generic *)&cmd, sizeof(cmd), (u_char *)&posdata,
1923 	    sizeof(posdata), ST_RETRIES, 30000, NULL,
1924 	    SCSI_SILENT | SCSI_DATA_IN);
1925 
1926 	if (error == 0) {
1927 #if	0
1928 		printf("posdata:");
1929 		for (hard = 0; hard < sizeof(posdata); hard++)
1930 			printf("%02x ", posdata[hard] & 0xff);
1931 		printf("\n");
1932 #endif
1933 		if (posdata[0] & 0x4)	/* Block Position Unknown */
1934 			error = EINVAL;
1935 		else
1936 			*blkptr = _4btol(&posdata[4]);
1937 	}
1938 	return (error);
1939 }
1940 
1941 int
1942 st_setpos(st, hard, blkptr)
1943 	struct st_softc *st;
1944 	int hard;
1945 	u_int32_t *blkptr;
1946 {
1947 	int error;
1948 	struct scsipi_generic cmd;
1949 
1950 	/*
1951 	 * First flush any pending writes. Strictly speaking,
1952 	 * we're not supposed to have to worry about this,
1953 	 * but let's be untrusting.
1954 	 */
1955 	error = st_write_filemarks(st, 0, SCSI_SILENT);
1956 
1957 	/*
1958 	 * The latter case is for 'write protected' tapes
1959 	 * which are too stupid to recognize a zero count
1960 	 * for writing filemarks as a no-op.
1961 	 */
1962 	if (error != 0 && error != EACCES)
1963 		return (error);
1964 
1965 	bzero(&cmd, sizeof(cmd));
1966 	cmd.opcode = LOCATE;
1967 	if (hard)
1968 		cmd.bytes[0] = 1 << 2;
1969 	_lto4b(*blkptr, &cmd.bytes[2]);
1970 	error = scsipi_command(st->sc_link, &cmd, sizeof(cmd),
1971 	    NULL, 0, ST_RETRIES, 1800000, NULL, 0);
1972 	/*
1973 	 * XXX: Note file && block number position now unknown (if
1974 	 * XXX: these things ever start being maintained in this driver)
1975 	 */
1976 	return (error);
1977 }
1978 
1979 
1980 /*
1981  * Look at the returned sense and act on the error and detirmine
1982  * The unix error number to pass back... (0 = report no error)
1983  *                            (-1 = continue processing)
1984  */
1985 int
1986 st_interpret_sense(xs)
1987 	struct scsipi_xfer *xs;
1988 {
1989 	struct scsipi_link *sc_link = xs->sc_link;
1990 	struct scsipi_sense_data *sense = &xs->sense.scsi_sense;
1991 	struct buf *bp = xs->bp;
1992 	struct st_softc *st = sc_link->device_softc;
1993 	u_int8_t key;
1994 	int32_t info;
1995 
1996 	/*
1997 	 * Get the sense fields and work out what code
1998 	 */
1999 	if (sense->error_code & SSD_ERRCODE_VALID)
2000 		info = _4btol(sense->info);
2001 	else
2002 		info = xs->datalen;	/* bad choice if fixed blocks */
2003 	if ((sc_link->flags & SDEV_OPEN) == 0)
2004 		return (-1);		/* not open yet, let generic handle */
2005 	else if ((sense->error_code & SSD_ERRCODE) != 0x70)
2006 		return (-1);		/* let the generic code handle it */
2007 #ifdef SCSIVERBOSE
2008 	else if ((xs->flags & SCSI_SILENT) == 0)
2009 		scsi_print_sense(xs, 0);    /* tell folks what happened */
2010 #endif
2011 	if (st->flags & ST_FIXEDBLOCKS) {
2012 		xs->resid = info * st->blksize;
2013 		if (sense->flags & SSD_EOM) {
2014 			st->flags |= ST_EIO_PENDING;
2015 			if (bp)
2016 				bp->b_resid = xs->resid;
2017 		}
2018 		if (sense->flags & SSD_FILEMARK) {
2019 			st->flags |= ST_AT_FILEMARK;
2020 			if (bp)
2021 				bp->b_resid = xs->resid;
2022 		}
2023 		if (sense->flags & SSD_ILI) {
2024 			st->flags |= ST_EIO_PENDING;
2025 			if (bp)
2026 				bp->b_resid = xs->resid;
2027 			if (sense->error_code & SSD_ERRCODE_VALID &&
2028 			    (xs->flags & SCSI_SILENT) == 0)
2029 				printf("%s: block wrong size, %d blocks residual\n",
2030 				    st->sc_dev.dv_xname, info);
2031 
2032 			/*
2033 			 * This quirk code helps the drive read
2034 			 * the first tape block, regardless of
2035 			 * format.  That is required for these
2036 			 * drives to return proper MODE SENSE
2037 			 * information.
2038 			 */
2039 			if ((st->quirks & ST_Q_SENSE_HELP) &&
2040 			    !(sc_link->flags & SDEV_MEDIA_LOADED))
2041 				st->blksize -= 512;
2042 		}
2043 		/*
2044 		 * If data wanted and no data was tranfered, do it immediatly
2045 		 */
2046 		if (xs->datalen && xs->resid >= xs->datalen) {
2047 			if (st->flags & ST_EIO_PENDING)
2048 				return (EIO);
2049 			if (st->flags & ST_AT_FILEMARK) {
2050 				if (bp)
2051 					bp->b_resid = xs->resid;
2052 				return (0);
2053 			}
2054 		}
2055 	} else {		/* must be variable mode */
2056 		xs->resid = xs->datalen;	/* to be sure */
2057 		if (sense->flags & SSD_EOM)
2058 			return (EIO);
2059 		if (sense->flags & SSD_FILEMARK) {
2060 			if (bp)
2061 				bp->b_resid = bp->b_bcount;
2062 			return (0);
2063 		}
2064 		if (sense->flags & SSD_ILI) {
2065 			if (info < 0) {
2066 				/*
2067 				 * the record was bigger than the read
2068 				 */
2069 				if ((xs->flags & SCSI_SILENT) == 0)
2070 					printf("%s: %d-byte record too big\n",
2071 					    st->sc_dev.dv_xname,
2072 					    xs->datalen - info);
2073 				return (EIO);
2074 			}
2075 			xs->resid = info;
2076 			if (bp)
2077 				bp->b_resid = info;
2078 		}
2079 	}
2080 	key = sense->flags & SSD_KEY;
2081 
2082 	if (key == 0x8) {
2083 		/*
2084 		 * This quirk code helps the drive read the
2085 		 * first tape block, regardless of format.  That
2086 		 * is required for these drives to return proper
2087 		 * MODE SENSE information.
2088 		 */
2089 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2090 		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
2091 			/* still starting */
2092 			st->blksize -= 512;
2093 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2094 			st->flags |= ST_BLANK_READ;
2095 			xs->resid = xs->datalen;
2096 			if (bp) {
2097 				bp->b_resid = xs->resid;
2098 				/* return an EOF */
2099 			}
2100 			return (0);
2101 		}
2102 	}
2103 	return (-1);		/* let the default/generic handler handle it */
2104 }
2105 
2106 /*
2107  * The quirk here is that the drive returns some value to st_mode_sense
2108  * incorrectly until the tape has actually passed by the head.
2109  *
2110  * The method is to set the drive to large fixed-block state (user-specified
2111  * density and 1024-byte blocks), then read and rewind to get it to sense the
2112  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2113  * work, as a last resort, try variable- length blocks.  The result will be
2114  * the ability to do an accurate st_mode_sense.
2115  *
2116  * We know we can do a rewind because we just did a load, which implies rewind.
2117  * Rewind seems preferable to space backward if we have a virgin tape.
2118  *
2119  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2120  * error processing, both part of st_interpret_sense.
2121  */
2122 int
2123 st_touch_tape(st)
2124 	struct st_softc *st;
2125 {
2126 	char *buf;
2127 	int readsize;
2128 	int error;
2129 
2130 	buf = malloc(1024, M_TEMP, M_NOWAIT);
2131 	if (buf == NULL)
2132 		return (ENOMEM);
2133 
2134 	if ((error = st_mode_sense(st, 0)) != 0)
2135 		goto bad;
2136 	st->blksize = 1024;
2137 	do {
2138 		switch (st->blksize) {
2139 		case 512:
2140 		case 1024:
2141 			readsize = st->blksize;
2142 			st->flags |= ST_FIXEDBLOCKS;
2143 			break;
2144 		default:
2145 			readsize = 1;
2146 			st->flags &= ~ST_FIXEDBLOCKS;
2147 		}
2148 		if ((error = st_mode_select(st, 0)) != 0)
2149 			goto bad;
2150 		st_read(st, buf, readsize, SCSI_SILENT);	/* XXX */
2151 		if ((error = st_rewind(st, 0, 0)) != 0) {
2152 bad:			free(buf, M_TEMP);
2153 			return (error);
2154 		}
2155 	} while (readsize != 1 && readsize > st->blksize);
2156 
2157 	free(buf, M_TEMP);
2158 	return (0);
2159 }
2160 
2161 int
2162 stdump(dev, blkno, va, size)
2163 	dev_t dev;
2164 	daddr_t blkno;
2165 	caddr_t va;
2166 	size_t size;
2167 {
2168 
2169 	/* Not implemented. */
2170 	return (ENXIO);
2171 }
2172