xref: /netbsd-src/sys/dev/scsipi/st.c (revision 5e4c038a45edbc7d63b7c2daa76e29f88b64a4e3)
1 /*	$NetBSD: st.c,v 1.155 2002/05/05 15:16:31 bouyer Exp $ */
2 /*-
3  * Copyright (c) 1998 The NetBSD Foundation, Inc.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Charles M. Hannum.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *        This product includes software developed by the NetBSD
20  *        Foundation, Inc. and its contributors.
21  * 4. Neither the name of The NetBSD Foundation nor the names of its
22  *    contributors may be used to endorse or promote products derived
23  *    from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 /*
39  * Originally written by Julian Elischer (julian@tfs.com)
40  * for TRW Financial Systems for use under the MACH(2.5) operating system.
41  *
42  * TRW Financial Systems, in accordance with their agreement with Carnegie
43  * Mellon University, makes this software available to CMU to distribute
44  * or use in any manner that they see fit as long as this message is kept with
45  * the software. For this reason TFS also grants any other persons or
46  * organisations permission to use or modify this software.
47  *
48  * TFS supplies this software to be publicly redistributed
49  * on the understanding that TFS is not responsible for the correct
50  * functioning of this software in any circumstances.
51  *
52  * Ported to run under 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
53  * major changes by Julian Elischer (julian@jules.dialix.oz.au) May 1993
54  *
55  * A lot of rewhacking done by mjacob (mjacob@nas.nasa.gov).
56  */
57 
58 #include <sys/cdefs.h>
59 __KERNEL_RCSID(0, "$NetBSD: st.c,v 1.155 2002/05/05 15:16:31 bouyer Exp $");
60 
61 #include "opt_scsi.h"
62 
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/fcntl.h>
66 #include <sys/errno.h>
67 #include <sys/ioctl.h>
68 #include <sys/malloc.h>
69 #include <sys/buf.h>
70 #include <sys/proc.h>
71 #include <sys/user.h>
72 #include <sys/mtio.h>
73 #include <sys/device.h>
74 #include <sys/conf.h>
75 #include <sys/kernel.h>
76 #include <sys/vnode.h>
77 
78 #include <dev/scsipi/scsi_all.h>
79 #include <dev/scsipi/scsi_tape.h>
80 #include <dev/scsipi/stvar.h>
81 
82 /* Defines for device specific stuff */
83 #define DEF_FIXED_BSIZE  512
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 STNMINOR	16
89 
90 #define NORMAL_MODE	0
91 #define NOREW_MODE	1
92 #define EJECT_MODE	2
93 #define CTRL_MODE	3
94 
95 #define	FALSE		0
96 #define	TRUE		1
97 
98 #ifndef		ST_MOUNT_DELAY
99 #define		ST_MOUNT_DELAY		0
100 #endif
101 
102 /*
103  * Define various devices that we know mis-behave in some way,
104  * and note how they are bad, so we can correct for them
105  */
106 
107 const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
108 	{{T_SEQUENTIAL, T_REMOV,
109 	 "        ", "                ", "    "}, {0, 0, {
110 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
111 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
112 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
113 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
114 	}}},
115 	{{T_SEQUENTIAL, T_REMOV,
116 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
117 		{0, 0, 0},				/* minor 0-3 */
118 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
119 		{0, 0, QIC_150},			/* minor 8-11 */
120 		{0, 0, QIC_120}				/* minor 12-15 */
121 	}}},
122  	{{T_SEQUENTIAL, T_REMOV,
123  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
124 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
125 		{0, 0, QIC_525},			/* minor 4-7 */
126 		{0, 0, QIC_150},			/* minor 8-11 */
127 		{0, 0, QIC_120}				/* minor 12-15 */
128 	}}},
129 	/*
130 	 * lacking a manual for the 4200, it's not clear what the
131 	 * specific density codes should be- the device is a 2.5GB
132 	 * capable QIC drive, those density codes aren't readily
133 	 * availabel. The 'default' will just have to do.
134 	 */
135  	{{T_SEQUENTIAL, T_REMOV,
136  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
137 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
138 		{0, 0, QIC_525},			/* minor 4-7 */
139 		{0, 0, QIC_150},			/* minor 8-11 */
140 		{0, 0, QIC_120}				/* minor 12-15 */
141 	}}},
142 	/*
143 	 * At least -005 and -007 need this.  I'll assume they all do unless I
144 	 * hear otherwise.  - mycroft, 31MAR1994
145 	 */
146 	{{T_SEQUENTIAL, T_REMOV,
147 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
148 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
149 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
150 		{0, 0, QIC_150},			/* minor 8-11 */
151 		{0, 0, QIC_120}				/* minor 12-15 */
152 	}}},
153 	/*
154 	 * One user reports that this works for his tape drive.  It probably
155 	 * needs more work.  - mycroft, 09APR1994
156 	 */
157 	{{T_SEQUENTIAL, T_REMOV,
158 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
159 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
160 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
161 		{0, 0, QIC_150},			/* minor 8-11 */
162 		{0, 0, QIC_120}				/* minor 12-15 */
163 	}}},
164 	{{T_SEQUENTIAL, T_REMOV,
165 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
166 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
167 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
168 		{0, 0, QIC_150},			/* minor 8-11 */
169 		{0, 0, QIC_120}				/* minor 12-15 */
170 	}}},
171 	{{T_SEQUENTIAL, T_REMOV,
172 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
173 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
174 		{0, 0, QIC_150},			/* minor 4-7 */
175 		{0, 0, QIC_120},			/* minor 8-11 */
176 		{0, 0, QIC_24}				/* minor 12-15 */
177 	}}},
178 	{{T_SEQUENTIAL, T_REMOV,
179 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
180 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
181 		{0, 0, QIC_150},			/* minor 4-7 */
182 		{0, 0, QIC_120},			/* minor 8-11 */
183 		{0, 0, QIC_24}				/* minor 12-15 */
184 	}}},
185 	{{T_SEQUENTIAL, T_REMOV,
186 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
187 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
188 		{0, 0, QIC_11},				/* minor 4-7 */
189 		{0, 0, QIC_24},				/* minor 8-11 */
190 		{0, 0, QIC_24}				/* minor 12-15 */
191 	}}},
192 	{{T_SEQUENTIAL, T_REMOV,
193 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
194 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
195 		{0, 0, QIC_24},				/* minor 4-7 */
196 		{0, 0, QIC_120},			/* minor 8-11 */
197 		{0, 0, QIC_150}				/* minor 12-15 */
198 	}}},
199 	{{T_SEQUENTIAL, T_REMOV,
200 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
201 		{0, 0, 0},				/* minor 0-3 */
202 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
203 		{0, 0, QIC_150},			/* minor 8-11 */
204 		{0, 0, QIC_120}				/* minor 12-15 */
205 	}}},
206 	{{T_SEQUENTIAL, T_REMOV,
207 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
208 		{0, 0, 0},				/* minor 0-3 */
209 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
210 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
211 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
212 	}}},
213 	{{T_SEQUENTIAL, T_REMOV,
214 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
215 		{0, 0, 0},				/* minor 0-3 */
216 		{0, 0, 0},				/* minor 4-7 */
217 		{0, 0, 0},				/* minor 8-11 */
218 		{0, 0, 0}				/* minor 12-15 */
219 	}}},
220 	{{T_SEQUENTIAL, T_REMOV,
221 	 "STK",      "9490",             ""},
222 				{ST_Q_FORCE_BLKSIZE, 0, {
223 		{0, 0, 0},				/* minor 0-3 */
224 		{0, 0, 0},				/* minor 4-7 */
225 		{0, 0, 0},				/* minor 8-11 */
226 		{0, 0, 0}				/* minor 12-15 */
227 	}}},
228 	{{T_SEQUENTIAL, T_REMOV,
229 	 "STK",      "SD-3",             ""},
230 				{ST_Q_FORCE_BLKSIZE, 0, {
231 		{0, 0, 0},				/* minor 0-3 */
232 		{0, 0, 0},				/* minor 4-7 */
233 		{0, 0, 0},				/* minor 8-11 */
234 		{0, 0, 0}				/* minor 12-15 */
235 	}}},
236 	{{T_SEQUENTIAL, T_REMOV,
237 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
238 		{0, 0, 0},				/* minor 0-3 */
239 		{0, 0, 0},				/* minor 4-7 */
240 		{0, 0, 0},				/* minor 8-11 */
241 		{0, 0, 0}				/* minor 12-15 */
242 	}}},
243 	{{T_SEQUENTIAL, T_REMOV,
244 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
245 		{0, 0, QIC_3095},			/* minor 0-3 */
246 		{0, 0, QIC_3095},			/* minor 4-7 */
247 		{0, 0, QIC_3095},			/* minor 8-11 */
248 		{0, 0, QIC_3095},			/* minor 12-15 */
249 	}}},
250 #if 0
251 	{{T_SEQUENTIAL, T_REMOV,
252 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
253 		{0, 0, 0},				/* minor 0-3 */
254 		{0, 0, 0},				/* minor 4-7 */
255 		{0, 0, 0},				/* minor 8-11 */
256 		{0, 0, 0}				/* minor 12-15 */
257 	}}},
258 #endif
259 	{{T_SEQUENTIAL, T_REMOV,
260 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
261 		{0, 0, 0},			        /* minor 0-3 */
262 		{0, 0, 0},			        /* minor 4-7 */
263 		{0, 0, 0},			        /* minor 8-11 */
264 		{0, 0, 0}			        /* minor 12-15 */
265 	}}},
266 	{{T_SEQUENTIAL, T_REMOV,
267 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
268 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
269 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
270 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
271 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
272 	}}},
273 	{{T_SEQUENTIAL, T_REMOV,
274 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
275 		{0, 0, 0},                              /* minor 0-3 */
276 		{0, 0, 0},                              /* minor 4-7 */
277 		{0, 0, 0},                              /* minor 8-11 */
278 		{0, 0, 0}                               /* minor 12-15 */
279 	}}},
280 	{{T_SEQUENTIAL, T_REMOV,
281 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
282 		{0, 0, 0},			       /* minor 0-3 */
283 		{0, 0, 0},			       /* minor 4-7 */
284 		{0, 0, 0},			       /* minor 8-11 */
285 		{0, 0, 0}			       /* minor 12-15 */
286 	}}},
287 };
288 
289 #define NOEJECT 0
290 #define EJECT 1
291 
292 void	st_identify_drive __P((struct st_softc *,
293 	    struct scsipi_inquiry_pattern *));
294 void	st_loadquirks __P((struct st_softc *));
295 int	st_mount_tape __P((dev_t, int));
296 void	st_unmount __P((struct st_softc *, boolean));
297 int	st_decide_mode __P((struct st_softc *, boolean));
298 void	ststart __P((struct scsipi_periph *));
299 void	stdone __P((struct scsipi_xfer *));
300 int	st_read __P((struct st_softc *, char *, int, int));
301 int	st_space __P((struct st_softc *, int, u_int, int));
302 int	st_write_filemarks __P((struct st_softc *, int, int));
303 int	st_check_eod __P((struct st_softc *, boolean, int *, int));
304 int	st_load __P((struct st_softc *, u_int, int));
305 int	st_rewind __P((struct st_softc *, u_int, int));
306 int	st_interpret_sense __P((struct scsipi_xfer *));
307 int	st_touch_tape __P((struct st_softc *));
308 int	st_erase __P((struct st_softc *, int full, int flags));
309 int	st_rdpos __P((struct st_softc *, int, u_int32_t *));
310 int	st_setpos __P((struct st_softc *, int, u_int32_t *));
311 
312 const struct scsipi_periphsw st_switch = {
313 	st_interpret_sense,
314 	ststart,
315 	NULL,
316 	stdone
317 };
318 
319 #if	defined(ST_ENABLE_EARLYWARN)
320 #define	ST_INIT_FLAGS	ST_EARLYWARN
321 #else
322 #define	ST_INIT_FLAGS	0
323 #endif
324 
325 /*
326  * The routine called by the low level scsi routine when it discovers
327  * A device suitable for this driver
328  */
329 void
330 stattach(parent, st, aux)
331 	struct device *parent;
332 	struct st_softc *st;
333 	void *aux;
334 {
335 	struct scsipibus_attach_args *sa = aux;
336 	struct scsipi_periph *periph = sa->sa_periph;
337 
338 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
339 
340 	/*
341 	 * Store information needed to contact our base driver
342 	 */
343 	st->sc_periph = periph;
344 	periph->periph_dev = &st->sc_dev;
345 	periph->periph_switch = &st_switch;
346 
347 	/*
348 	 * Set initial flags
349 	 */
350 
351 	st->flags = ST_INIT_FLAGS;
352 
353 	/*
354 	 * Check if the drive is a known criminal and take
355 	 * Any steps needed to bring it into line
356 	 */
357 	st_identify_drive(st, &sa->sa_inqbuf);
358 	/*
359 	 * Use the subdriver to request information regarding the drive.
360 	 */
361 	printf("\n");
362 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
363 	if (scsipi_test_unit_ready(periph,
364 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
365 	    st->ops(st, ST_OPS_MODESENSE,
366 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
367 		printf("drive empty\n");
368 	else {
369 		printf("density code %d, ", st->media_density);
370 		if (st->media_blksize > 0)
371 			printf("%d-byte", st->media_blksize);
372 		else
373 			printf("variable");
374 		printf(" blocks, write-%s\n",
375 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
376 	}
377 
378 	/*
379 	 * Set up the buf queue for this device
380 	 */
381 	BUFQ_INIT(&st->buf_queue);
382 
383 #if NRND > 0
384 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
385 			  RND_TYPE_TAPE, 0);
386 #endif
387 }
388 
389 int
390 stactivate(self, act)
391 	struct device *self;
392 	enum devact act;
393 {
394 	int rv = 0;
395 
396 	switch (act) {
397 	case DVACT_ACTIVATE:
398 		rv = EOPNOTSUPP;
399 		break;
400 
401 	case DVACT_DEACTIVATE:
402 		/*
403 		 * Nothing to do; we key off the device's DVF_ACTIVE.
404 		 */
405 		break;
406 	}
407 	return (rv);
408 }
409 
410 int
411 stdetach(self, flags)
412 	struct device *self;
413 	int flags;
414 {
415 	struct st_softc *st = (struct st_softc *)self;
416 	struct buf *bp;
417 	int s, bmaj, cmaj, mn;
418 
419 	/* locate the major number */
420 	for (bmaj = 0; bmaj <= nblkdev; bmaj++)
421 		if (bdevsw[bmaj].d_open == stopen)
422 			break;
423 	for (cmaj = 0; cmaj <= nchrdev; cmaj++)
424 		if (cdevsw[cmaj].d_open == stopen)
425 			break;
426 
427 	s = splbio();
428 
429 	/* Kill off any queued buffers. */
430 	while ((bp = BUFQ_FIRST(&st->buf_queue)) != NULL) {
431 		BUFQ_REMOVE(&st->buf_queue, bp);
432 		bp->b_error = EIO;
433 		bp->b_flags |= B_ERROR;
434 		bp->b_resid = bp->b_bcount;
435 		biodone(bp);
436 	}
437 
438 	/* Kill off any pending commands. */
439 	scsipi_kill_pending(st->sc_periph);
440 
441 	splx(s);
442 
443 	/* Nuke the vnodes for any open instances */
444 	mn = STUNIT(self->dv_unit);
445 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
446 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
447 
448 
449 #if NRND > 0
450 	/* Unhook the entropy source. */
451 	rnd_detach_source(&st->rnd_source);
452 #endif
453 
454 	return (0);
455 }
456 
457 /*
458  * Use the inquiry routine in 'scsi_base' to get drive info so we can
459  * Further tailor our behaviour.
460  */
461 void
462 st_identify_drive(st, inqbuf)
463 	struct st_softc *st;
464 	struct scsipi_inquiry_pattern *inqbuf;
465 {
466 	struct st_quirk_inquiry_pattern *finger;
467 	int priority;
468 
469 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
470 	    (caddr_t)st_quirk_patterns,
471 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
472 	    sizeof(st_quirk_patterns[0]), &priority);
473 	if (priority != 0) {
474 		st->quirkdata = &finger->quirkdata;
475 		st->drive_quirks = finger->quirkdata.quirks;
476 		st->quirks = finger->quirkdata.quirks;	/* start value */
477 		st->page_0_size = finger->quirkdata.page_0_size;
478 		st_loadquirks(st);
479 	}
480 }
481 
482 /*
483  * initialise the subdevices to the default (QUIRK) state.
484  * this will remove any setting made by the system operator or previous
485  * operations.
486  */
487 void
488 st_loadquirks(st)
489 	struct st_softc *st;
490 {
491 	int i;
492 	struct	modes *mode;
493 	struct	modes *mode2;
494 
495 	mode = st->quirkdata->modes;
496 	mode2 = st->modes;
497 	for (i = 0; i < 4; i++) {
498 		memset(mode2, 0, sizeof(struct modes));
499 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
500 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
501 		    DENSITY_SET_BY_USER);
502 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
503 			mode2->blksize = mode->blksize;
504 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
505 		}
506 		if (mode->density) {
507 			mode2->density = mode->density;
508 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
509 		}
510 		mode2->quirks |= mode->quirks;
511 		mode++;
512 		mode2++;
513 	}
514 }
515 
516 /*
517  * open the device.
518  */
519 int
520 stopen(dev, flags, mode, p)
521 	dev_t dev;
522 	int flags;
523 	int mode;
524 	struct proc *p;
525 {
526 	u_int stmode, dsty;
527 	int error, sflags, unit, tries, ntries;
528 	struct st_softc *st;
529 	struct scsipi_periph *periph;
530 	struct scsipi_adapter *adapt;
531 
532 	unit = STUNIT(dev);
533 	if (unit >= st_cd.cd_ndevs)
534 		return (ENXIO);
535 	st = st_cd.cd_devs[unit];
536 	if (st == NULL)
537 		return (ENXIO);
538 
539 	stmode = STMODE(dev);
540 	dsty = STDSTY(dev);
541 
542 	periph = st->sc_periph;
543 	adapt = periph->periph_channel->chan_adapter;
544 
545 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
546 	    unit, st_cd.cd_ndevs));
547 
548 
549 	/*
550 	 * Only allow one at a time
551 	 */
552 	if (periph->periph_flags & PERIPH_OPEN) {
553 		printf("%s: already open\n", st->sc_dev.dv_xname);
554 		return (EBUSY);
555 	}
556 
557 	if ((error = scsipi_adapter_addref(adapt)) != 0)
558 		return (error);
559 
560 	/*
561 	 * clear any latched errors.
562 	 */
563 	st->mt_resid = 0;
564 	st->mt_erreg = 0;
565 	st->asc = 0;
566 	st->ascq = 0;
567 
568 	/*
569 	 * Catch any unit attention errors. Be silent about this
570 	 * unless we're already mounted. We ignore media change
571 	 * if we're in control mode or not mounted yet.
572 	 */
573 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
574 #ifdef SCSIDEBUG
575 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
576 #else
577 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
578 #endif
579 	} else
580 		sflags = 0;
581 
582 	/*
583 	 * If we're already mounted or we aren't configured for
584 	 * a mount delay, only try a test unit ready once. Otherwise,
585 	 * try up to ST_MOUNT_DELAY times with a rest interval of
586 	 * one second between each try.
587 	 */
588 
589 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
590 		ntries = 1;
591 	} else {
592 		ntries = ST_MOUNT_DELAY;
593 	}
594 
595 	for (error = tries = 0; tries < ntries; tries++) {
596 		int slpintr, oflags;
597 
598 		/*
599 		 * If we had no error, or we're opening the control mode
600 		 * device, we jump out right away.
601 		 */
602 
603 		error = scsipi_test_unit_ready(periph, sflags);
604 		if (error == 0 || stmode == CTRL_MODE) {
605 			break;
606 		}
607 
608 		/*
609 		 * We had an error.
610 		 *
611 		 * If we're already mounted or we aren't configured for
612 		 * a mount delay, or the error isn't a NOT READY error,
613 		 * skip to the error exit now.
614 		 */
615 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
616 		    (st->mt_key != SKEY_NOT_READY)) {
617 			goto bad;
618 		}
619 
620 		/*
621 		 * clear any latched errors.
622 		 */
623 		st->mt_resid = 0;
624 		st->mt_erreg = 0;
625 		st->asc = 0;
626 		st->ascq = 0;
627 
628 		/*
629 		 * Fake that we have the device open so
630 		 * we block other apps from getting in.
631 		 */
632 
633 		oflags = periph->periph_flags;
634 		periph->periph_flags |= PERIPH_OPEN;
635 
636 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
637 
638 		periph->periph_flags = oflags;	/* restore flags */
639 		if (slpintr) {
640 			goto bad;
641 		}
642 	}
643 
644 
645 	/*
646 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
647 	 * been opened to set defaults and perform other, usually non-I/O
648 	 * related, operations. In this case, do a quick check to see
649 	 * whether the unit actually had a tape loaded (this will be known
650 	 * as to whether or not we got a NOT READY for the above
651 	 * unit attention). If a tape is there, go do a mount sequence.
652 	 */
653 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
654 		periph->periph_flags |= PERIPH_OPEN;
655 		return (0);
656 	}
657 
658 	/*
659 	 * If we get this far and had an error set, that means we failed
660 	 * to pass the 'test unit ready' test for the non-controlmode device,
661 	 * so we bounce the open.
662 	 */
663 
664 	if (error)
665 		return (error);
666 
667 	/*
668 	 * Else, we're now committed to saying we're open.
669 	 */
670 
671 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
672 
673 	/*
674 	 * If it's a different mode, or if the media has been
675 	 * invalidated, unmount the tape from the previous
676 	 * session but continue with open processing
677 	 */
678 	if (st->last_dsty != dsty ||
679 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
680 		st_unmount(st, NOEJECT);
681 
682 	/*
683 	 * If we are not mounted, then we should start a new
684 	 * mount session.
685 	 */
686 	if (!(st->flags & ST_MOUNTED)) {
687 		if ((error = st_mount_tape(dev, flags)) != 0)
688 			goto bad;
689 		st->last_dsty = dsty;
690 	}
691 	if (!(st->quirks & ST_Q_NOPREVENT)) {
692 		scsipi_prevent(periph, PR_PREVENT,
693 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
694 	}
695 
696 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
697 	return (0);
698 
699 bad:
700 	st_unmount(st, NOEJECT);
701 	scsipi_adapter_delref(adapt);
702 	periph->periph_flags &= ~PERIPH_OPEN;
703 	return (error);
704 }
705 
706 /*
707  * close the device.. only called if we are the LAST
708  * occurence of an open device
709  */
710 int
711 stclose(dev, flags, mode, p)
712 	dev_t dev;
713 	int flags;
714 	int mode;
715 	struct proc *p;
716 {
717 	int stxx, error = 0;
718 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
719 	struct scsipi_periph *periph = st->sc_periph;
720 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
721 
722 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
723 
724 	/*
725 	 * Make sure that a tape opened in write-only mode will have
726 	 * file marks written on it when closed, even if not written to.
727 	 *
728 	 * This is for SUN compatibility. Actually, the Sun way of
729 	 * things is to:
730 	 *
731 	 *	only write filemarks if there are fmks to be written and
732 	 *   		- open for write (possibly read/write)
733 	 *		- the last operation was a write
734 	 * 	or:
735 	 *		- opened for wronly
736 	 *		- no data was written (including filemarks)
737 	 */
738 
739 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
740 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
741 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
742 		int nm;
743 		error = st_check_eod(st, FALSE, &nm, 0);
744 	}
745 
746 	/*
747 	 * Allow robots to eject tape if needed.
748 	 */
749 	scsipi_prevent(periph, PR_ALLOW,
750 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
751 
752 	switch (STMODE(dev)) {
753 	case NORMAL_MODE:
754 		st_unmount(st, NOEJECT);
755 		break;
756 	case NOREW_MODE:
757 	case CTRL_MODE:
758 		/*
759 		 * Leave mounted unless media seems to have been removed.
760 		 *
761 		 * Otherwise, if we're to terminate a tape with more than one
762 		 * filemark [ and because we're not rewinding here ], backspace
763 		 * one filemark so that later appends will see an unbroken
764 		 * sequence of:
765 		 *
766 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
767 		 */
768 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
769 			st_unmount(st, NOEJECT);
770 		} else if (error == 0) {
771 			/*
772 			 * ST_WRITTEN was preserved from above.
773 			 *
774 			 * All we need to know here is:
775 			 *
776 			 *	Were we writing this tape and was the last
777 			 *	operation a write?
778 			 *
779 			 *	Are there supposed to be 2FM at EOD?
780 			 *
781 			 * If both statements are true, then we backspace
782 			 * one filemark.
783 			 */
784 			stxx |= (st->flags & ST_2FM_AT_EOD);
785 			if ((flags & FWRITE) != 0 &&
786 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
787 				error = st_space(st, -1, SP_FILEMARKS, 0);
788 			}
789 		}
790 		break;
791 	case EJECT_MODE:
792 		st_unmount(st, EJECT);
793 		break;
794 	}
795 
796 	scsipi_wait_drain(periph);
797 
798 	scsipi_adapter_delref(adapt);
799 	periph->periph_flags &= ~PERIPH_OPEN;
800 
801 	return (error);
802 }
803 
804 /*
805  * Start a new mount session.
806  * Copy in all the default parameters from the selected device mode.
807  * and try guess any that seem to be defaulted.
808  */
809 int
810 st_mount_tape(dev, flags)
811 	dev_t dev;
812 	int flags;
813 {
814 	int unit;
815 	u_int dsty;
816 	struct st_softc *st;
817 	struct scsipi_periph *periph;
818 	int error = 0;
819 
820 	unit = STUNIT(dev);
821 	dsty = STDSTY(dev);
822 	st = st_cd.cd_devs[unit];
823 	periph = st->sc_periph;
824 
825 	if (st->flags & ST_MOUNTED)
826 		return (0);
827 
828 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
829 	st->flags |= ST_NEW_MOUNT;
830 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
831 	/*
832 	 * If the media is new, then make sure we give it a chance to
833 	 * to do a 'load' instruction.  (We assume it is new.)
834 	 */
835 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
836 		return (error);
837 	/*
838 	 * Throw another dummy instruction to catch
839 	 * 'Unit attention' errors. Many drives give
840 	 * these after doing a Load instruction (with
841 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
842 	 */
843 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
844 
845 	/*
846 	 * Some devices can't tell you much until they have been
847 	 * asked to look at the media. This quirk does this.
848 	 */
849 	if (st->quirks & ST_Q_SENSE_HELP)
850 		if ((error = st_touch_tape(st)) != 0)
851 			return (error);
852 	/*
853 	 * Load the physical device parameters
854 	 * loads: blkmin, blkmax
855 	 */
856 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
857 		return (error);
858 	/*
859 	 * Load the media dependent parameters
860 	 * includes: media_blksize,media_density,numblks
861 	 * As we have a tape in, it should be reflected here.
862 	 * If not you may need the "quirk" above.
863 	 */
864 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
865 		return (error);
866 	/*
867 	 * If we have gained a permanent density from somewhere,
868 	 * then use it in preference to the one supplied by
869 	 * default by the driver.
870 	 */
871 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
872 		st->density = st->modes[dsty].density;
873 	else
874 		st->density = st->media_density;
875 	/*
876 	 * If we have gained a permanent blocksize
877 	 * then use it in preference to the one supplied by
878 	 * default by the driver.
879 	 */
880 	st->flags &= ~ST_FIXEDBLOCKS;
881 	if (st->modeflags[dsty] &
882 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
883 		st->blksize = st->modes[dsty].blksize;
884 		if (st->blksize)
885 			st->flags |= ST_FIXEDBLOCKS;
886 	} else {
887 		if ((error = st_decide_mode(st, FALSE)) != 0)
888 			return (error);
889 	}
890 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
891 		/* ATAPI will return ENODEV for this, and this may be OK */
892 		if (error != ENODEV) {
893 			printf("%s: cannot set selected mode\n",
894 			    st->sc_dev.dv_xname);
895 			return (error);
896 		}
897 	}
898 	st->flags &= ~ST_NEW_MOUNT;
899 	st->flags |= ST_MOUNTED;
900 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
901 	st->blkno = st->fileno = (daddr_t) 0;
902 	return (0);
903 }
904 
905 /*
906  * End the present mount session.
907  * Rewind, and optionally eject the tape.
908  * Reset various flags to indicate that all new
909  * operations require another mount operation
910  */
911 void
912 st_unmount(st, eject)
913 	struct st_softc *st;
914 	boolean eject;
915 {
916 	struct scsipi_periph *periph = st->sc_periph;
917 	int nmarks;
918 
919 	if ((st->flags & ST_MOUNTED) == 0)
920 		return;
921 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
922 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
923 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
924 
925 	/*
926 	 * Section 9.3.3 of the SCSI specs states that a device shall return
927 	 * the density value specified in the last succesfull MODE SELECT
928 	 * after an unload operation, in case it is not able to
929 	 * automatically determine the density of the new medium.
930 	 *
931 	 * So we instruct the device to use the default density, which will
932 	 * prevent the use of stale density values (in particular,
933 	 * in st_touch_tape().
934 	 */
935 	st->density = 0;
936 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
937 		printf("%s: WARNING: cannot revert to default density\n",
938 			st->sc_dev.dv_xname);
939 	}
940 
941 	if (eject) {
942 		if (!(st->quirks & ST_Q_NOPREVENT)) {
943 			scsipi_prevent(periph, PR_ALLOW,
944 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
945 			    XS_CTL_IGNORE_NOT_READY);
946 		}
947 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
948 		st->blkno = st->fileno = (daddr_t) -1;
949 	} else {
950 		st->blkno = st->fileno = (daddr_t) 0;
951 	}
952 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
953 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
954 }
955 
956 /*
957  * Given all we know about the device, media, mode, 'quirks' and
958  * initial operation, make a decision as to how we should be set
959  * to run (regarding blocking and EOD marks)
960  */
961 int
962 st_decide_mode(st, first_read)
963 	struct st_softc *st;
964 	boolean	first_read;
965 {
966 
967 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
968 
969 	/*
970 	 * If the drive can only handle fixed-length blocks and only at
971 	 * one size, perhaps we should just do that.
972 	 */
973 	if (st->blkmin && (st->blkmin == st->blkmax)) {
974 		st->flags |= ST_FIXEDBLOCKS;
975 		st->blksize = st->blkmin;
976 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
977 		    ("blkmin == blkmax of %d\n", st->blkmin));
978 		goto done;
979 	}
980 	/*
981 	 * If the tape density mandates (or even suggests) use of fixed
982 	 * or variable-length blocks, comply.
983 	 */
984 	switch (st->density) {
985 	case HALFINCH_800:
986 	case HALFINCH_1600:
987 	case HALFINCH_6250:
988 	case DDS:
989 		st->flags &= ~ST_FIXEDBLOCKS;
990 		st->blksize = 0;
991 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
992 		    ("density specified variable\n"));
993 		goto done;
994 	case QIC_11:
995 	case QIC_24:
996 	case QIC_120:
997 	case QIC_150:
998 	case QIC_525:
999 	case QIC_1320:
1000 	case QIC_3095:
1001 	case QIC_3220:
1002 		st->flags |= ST_FIXEDBLOCKS;
1003 		if (st->media_blksize > 0)
1004 			st->blksize = st->media_blksize;
1005 		else
1006 			st->blksize = DEF_FIXED_BSIZE;
1007 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1008 		    ("density specified fixed\n"));
1009 		goto done;
1010 	}
1011 	/*
1012 	 * If we're about to read the tape, perhaps we should choose
1013 	 * fixed or variable-length blocks and block size according to
1014 	 * what the drive found on the tape.
1015 	 */
1016 	if (first_read &&
1017 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1018 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1019 	    (st->media_blksize == 1024))) {
1020 		if (st->media_blksize > 0)
1021 			st->flags |= ST_FIXEDBLOCKS;
1022 		else
1023 			st->flags &= ~ST_FIXEDBLOCKS;
1024 		st->blksize = st->media_blksize;
1025 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1026 		    ("Used media_blksize of %d\n", st->media_blksize));
1027 		goto done;
1028 	}
1029 	/*
1030 	 * We're getting no hints from any direction.  Choose variable-
1031 	 * length blocks arbitrarily.
1032 	 */
1033 	st->flags &= ~ST_FIXEDBLOCKS;
1034 	st->blksize = 0;
1035 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1036 	    ("Give up and default to variable mode\n"));
1037 
1038 done:
1039 	/*
1040 	 * Decide whether or not to write two file marks to signify end-
1041 	 * of-data.  Make the decision as a function of density.  If
1042 	 * the decision is not to use a second file mark, the SCSI BLANK
1043 	 * CHECK condition code will be recognized as end-of-data when
1044 	 * first read.
1045 	 * (I think this should be a by-product of fixed/variable..julian)
1046 	 */
1047 	switch (st->density) {
1048 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1049 	case QIC_11:
1050 	case QIC_24:
1051 	case QIC_120:
1052 	case QIC_150:
1053 	case QIC_525:
1054 	case QIC_1320:
1055 	case QIC_3095:
1056 	case QIC_3220:
1057 		st->flags &= ~ST_2FM_AT_EOD;
1058 		break;
1059 	default:
1060 		st->flags |= ST_2FM_AT_EOD;
1061 	}
1062 	return (0);
1063 }
1064 
1065 /*
1066  * Actually translate the requested transfer into
1067  * one the physical driver can understand
1068  * The transfer is described by a buf and will include
1069  * only one physical transfer.
1070  */
1071 void
1072 ststrategy(bp)
1073 	struct buf *bp;
1074 {
1075 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1076 	int s;
1077 
1078 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1079 	    ("ststrategy %ld bytes @ blk %d\n", bp->b_bcount, bp->b_blkno));
1080 	/*
1081 	 * If it's a null transfer, return immediatly
1082 	 */
1083 	if (bp->b_bcount == 0)
1084 		goto done;
1085 
1086 	/* If offset is negative, error */
1087 	if (bp->b_blkno < 0) {
1088 		bp->b_error = EINVAL;
1089 		goto bad;
1090 	}
1091 
1092 	/*
1093 	 * Odd sized request on fixed drives are verboten
1094 	 */
1095 	if (st->flags & ST_FIXEDBLOCKS) {
1096 		if (bp->b_bcount % st->blksize) {
1097 			printf("%s: bad request, must be multiple of %d\n",
1098 			    st->sc_dev.dv_xname, st->blksize);
1099 			bp->b_error = EIO;
1100 			goto bad;
1101 		}
1102 	}
1103 	/*
1104 	 * as are out-of-range requests on variable drives.
1105 	 */
1106 	else if (bp->b_bcount < st->blkmin ||
1107 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1108 		printf("%s: bad request, must be between %d and %d\n",
1109 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1110 		bp->b_error = EIO;
1111 		goto bad;
1112 	}
1113 	s = splbio();
1114 
1115 	/*
1116 	 * Place it in the queue of activities for this tape
1117 	 * at the end (a bit silly because we only have on user..
1118 	 * (but it could fork()))
1119 	 */
1120 	BUFQ_INSERT_TAIL(&st->buf_queue, bp);
1121 
1122 	/*
1123 	 * Tell the device to get going on the transfer if it's
1124 	 * not doing anything, otherwise just wait for completion
1125 	 * (All a bit silly if we're only allowing 1 open but..)
1126 	 */
1127 	ststart(st->sc_periph);
1128 
1129 	splx(s);
1130 	return;
1131 bad:
1132 	bp->b_flags |= B_ERROR;
1133 done:
1134 	/*
1135 	 * Correctly set the buf to indicate a completed xfer
1136 	 */
1137 	bp->b_resid = bp->b_bcount;
1138 	biodone(bp);
1139 	return;
1140 }
1141 
1142 /*
1143  * ststart looks to see if there is a buf waiting for the device
1144  * and that the device is not already busy. If both are true,
1145  * It dequeues the buf and creates a scsi command to perform the
1146  * transfer required. The transfer request will call scsipi_done
1147  * on completion, which will in turn call this routine again
1148  * so that the next queued transfer is performed.
1149  * The bufs are queued by the strategy routine (ststrategy)
1150  *
1151  * This routine is also called after other non-queued requests
1152  * have been made of the scsi driver, to ensure that the queue
1153  * continues to be drained.
1154  * ststart() is called at splbio
1155  */
1156 void
1157 ststart(periph)
1158 	struct scsipi_periph *periph;
1159 {
1160 	struct st_softc *st = (void *)periph->periph_dev;
1161 	struct buf *bp;
1162 	struct scsi_rw_tape cmd;
1163 	int flags, error;
1164 
1165 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1166 	/*
1167 	 * See if there is a buf to do and we are not already
1168 	 * doing one
1169 	 */
1170 	while (periph->periph_active < periph->periph_openings) {
1171 		/* if a special awaits, let it proceed first */
1172 		if (periph->periph_flags & PERIPH_WAITING) {
1173 			periph->periph_flags &= ~PERIPH_WAITING;
1174 			wakeup((caddr_t)periph);
1175 			return;
1176 		}
1177 
1178 		if ((bp = BUFQ_FIRST(&st->buf_queue)) == NULL)
1179 			return;
1180 		BUFQ_REMOVE(&st->buf_queue, bp);
1181 
1182 		/*
1183 		 * If the device has been unmounted by the user
1184 		 * then throw away all requests until done.
1185 		 */
1186 		if ((st->flags & ST_MOUNTED) == 0 ||
1187 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
1188 			/* make sure that one implies the other.. */
1189 			periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1190 			bp->b_flags |= B_ERROR;
1191 			bp->b_error = EIO;
1192 			bp->b_resid = bp->b_bcount;
1193 			biodone(bp);
1194 			continue;
1195 		}
1196 		/*
1197 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1198 		 */
1199 		if (st->flags & ST_FIXEDBLOCKS) {
1200 			/*
1201 			 * If we are at a filemark but have not reported it yet
1202 			 * then we should report it now
1203 			 */
1204 			if (st->flags & ST_AT_FILEMARK) {
1205 				if ((bp->b_flags & B_READ) == B_WRITE) {
1206 					/*
1207 					 * Handling of ST_AT_FILEMARK in
1208 					 * st_space will fill in the right file
1209 					 * mark count.
1210 					 * Back up over filemark
1211 					 */
1212 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1213 						bp->b_flags |= B_ERROR;
1214 						bp->b_error = EIO;
1215 						biodone(bp);
1216 						continue;
1217 					}
1218 				} else {
1219 					bp->b_resid = bp->b_bcount;
1220 					bp->b_error = 0;
1221 					bp->b_flags &= ~B_ERROR;
1222 					st->flags &= ~ST_AT_FILEMARK;
1223 					biodone(bp);
1224 					continue;	/* seek more work */
1225 				}
1226 			}
1227 		}
1228 		/*
1229 		 * If we are at EOM but have not reported it
1230 		 * yet then we should report it now.
1231 		 */
1232 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1233 			bp->b_resid = bp->b_bcount;
1234 			if (st->flags & ST_EIO_PENDING) {
1235 				bp->b_error = EIO;
1236 				bp->b_flags |= B_ERROR;
1237 			}
1238 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1239 			biodone(bp);
1240 			continue;	/* seek more work */
1241 		}
1242 
1243 		/*
1244 		 * Fill out the scsi command
1245 		 */
1246 		memset(&cmd, 0, sizeof(cmd));
1247 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1248 		if ((bp->b_flags & B_READ) == B_WRITE) {
1249 			cmd.opcode = WRITE;
1250 			st->flags &= ~ST_FM_WRITTEN;
1251 			flags |= XS_CTL_DATA_OUT;
1252 		} else {
1253 			cmd.opcode = READ;
1254 			flags |= XS_CTL_DATA_IN;
1255 		}
1256 
1257 		/*
1258 		 * Handle "fixed-block-mode" tape drives by using the
1259 		 * block count instead of the length.
1260 		 */
1261 		if (st->flags & ST_FIXEDBLOCKS) {
1262 			cmd.byte2 |= SRW_FIXED;
1263 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1264 		} else
1265 			_lto3b(bp->b_bcount, cmd.len);
1266 
1267 		/*
1268 		 * Clear 'position updated' indicator
1269 		 */
1270 		st->flags &= ~ST_POSUPDATED;
1271 
1272 		/*
1273 		 * go ask the adapter to do all this for us
1274 		 */
1275 		error = scsipi_command(periph,
1276 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1277 		    (u_char *)bp->b_data, bp->b_bcount,
1278 		    0, ST_IO_TIME, bp, flags);
1279 		if (error) {
1280 			printf("%s: not queued, error %d\n",
1281 			    st->sc_dev.dv_xname, error);
1282 		}
1283 	} /* go back and see if we can cram more work in.. */
1284 }
1285 
1286 void
1287 stdone(xs)
1288 	struct scsipi_xfer *xs;
1289 {
1290 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1291 
1292 	if (xs->bp != NULL) {
1293 		if ((xs->bp->b_flags & B_READ) == B_WRITE) {
1294 			st->flags |= ST_WRITTEN;
1295 		} else {
1296 			st->flags &= ~ST_WRITTEN;
1297 		}
1298 #if NRND > 0
1299 		rnd_add_uint32(&st->rnd_source, xs->bp->b_blkno);
1300 #endif
1301 
1302 		if ((st->flags & ST_POSUPDATED) == 0) {
1303 			if (xs->bp->b_flags & B_ERROR) {
1304 				st->fileno = st->blkno = -1;
1305 			} else if (st->blkno != -1) {
1306 				if (st->flags & ST_FIXEDBLOCKS) {
1307 					st->blkno +=
1308 					    (xs->bp->b_bcount / st->blksize);
1309 				} else {
1310 					st->blkno++;
1311 				}
1312 			}
1313 		}
1314 	}
1315 }
1316 
1317 int
1318 stread(dev, uio, iomode)
1319 	dev_t dev;
1320 	struct uio *uio;
1321 	int iomode;
1322 {
1323 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1324 
1325 	return (physio(ststrategy, NULL, dev, B_READ,
1326 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1327 }
1328 
1329 int
1330 stwrite(dev, uio, iomode)
1331 	dev_t dev;
1332 	struct uio *uio;
1333 	int iomode;
1334 {
1335 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1336 
1337 	return (physio(ststrategy, NULL, dev, B_WRITE,
1338 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1339 }
1340 
1341 /*
1342  * Perform special action on behalf of the user;
1343  * knows about the internals of this device
1344  */
1345 int
1346 stioctl(dev, cmd, arg, flag, p)
1347 	dev_t dev;
1348 	u_long cmd;
1349 	caddr_t arg;
1350 	int flag;
1351 	struct proc *p;
1352 {
1353 	int error = 0;
1354 	int unit;
1355 	int number, nmarks, dsty;
1356 	int flags;
1357 	struct st_softc *st;
1358 	int hold_blksize;
1359 	u_int8_t hold_density;
1360 	struct mtop *mt = (struct mtop *) arg;
1361 
1362 	/*
1363 	 * Find the device that the user is talking about
1364 	 */
1365 	flags = 0;		/* give error messages, act on errors etc. */
1366 	unit = STUNIT(dev);
1367 	dsty = STDSTY(dev);
1368 	st = st_cd.cd_devs[unit];
1369 	hold_blksize = st->blksize;
1370 	hold_density = st->density;
1371 
1372 	switch ((u_int) cmd) {
1373 
1374 	case MTIOCGET: {
1375 		struct mtget *g = (struct mtget *) arg;
1376 		/*
1377 		 * (to get the current state of READONLY)
1378 		 */
1379 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1380 		if (error) {
1381 			/*
1382 			 * Ignore the error if in control mode;
1383 			 * this is mandated by st(4).
1384 			 */
1385 			if (STMODE(dev) != CTRL_MODE)
1386 				break;
1387 			error = 0;
1388 		}
1389 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1390 		memset(g, 0, sizeof(struct mtget));
1391 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1392 		g->mt_blksiz = st->blksize;
1393 		g->mt_density = st->density;
1394 		g->mt_mblksiz[0] = st->modes[0].blksize;
1395 		g->mt_mblksiz[1] = st->modes[1].blksize;
1396 		g->mt_mblksiz[2] = st->modes[2].blksize;
1397 		g->mt_mblksiz[3] = st->modes[3].blksize;
1398 		g->mt_mdensity[0] = st->modes[0].density;
1399 		g->mt_mdensity[1] = st->modes[1].density;
1400 		g->mt_mdensity[2] = st->modes[2].density;
1401 		g->mt_mdensity[3] = st->modes[3].density;
1402 		g->mt_fileno = st->fileno;
1403 		g->mt_blkno = st->blkno;
1404 		if (st->flags & ST_READONLY)
1405 			g->mt_dsreg |= MT_DS_RDONLY;
1406 		if (st->flags & ST_MOUNTED)
1407 			g->mt_dsreg |= MT_DS_MOUNTED;
1408 		g->mt_resid = st->mt_resid;
1409 		g->mt_erreg = st->mt_erreg;
1410 		/*
1411 		 * clear latched errors.
1412 		 */
1413 		st->mt_resid = 0;
1414 		st->mt_erreg = 0;
1415 		st->asc = 0;
1416 		st->ascq = 0;
1417 		break;
1418 	}
1419 	case MTIOCTOP: {
1420 
1421 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1422 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1423 			mt->mt_count));
1424 
1425 		/* compat: in U*x it is a short */
1426 		number = mt->mt_count;
1427 		switch ((short) (mt->mt_op)) {
1428 		case MTWEOF:	/* write an end-of-file record */
1429 			error = st_write_filemarks(st, number, flags);
1430 			break;
1431 		case MTBSF:	/* backward space file */
1432 			number = -number;
1433 		case MTFSF:	/* forward space file */
1434 			error = st_check_eod(st, FALSE, &nmarks, flags);
1435 			if (!error)
1436 				error = st_space(st, number - nmarks,
1437 				    SP_FILEMARKS, flags);
1438 			break;
1439 		case MTBSR:	/* backward space record */
1440 			number = -number;
1441 		case MTFSR:	/* forward space record */
1442 			error = st_check_eod(st, TRUE, &nmarks, flags);
1443 			if (!error)
1444 				error = st_space(st, number, SP_BLKS, flags);
1445 			break;
1446 		case MTREW:	/* rewind */
1447 			error = st_rewind(st, 0, flags);
1448 			break;
1449 		case MTOFFL:	/* rewind and put the drive offline */
1450 			st_unmount(st, EJECT);
1451 			break;
1452 		case MTNOP:	/* no operation, sets status only */
1453 			break;
1454 		case MTRETEN:	/* retension the tape */
1455 			error = st_load(st, LD_RETENSION, flags);
1456 			if (!error)
1457 				error = st_load(st, LD_LOAD, flags);
1458 			break;
1459 		case MTEOM:	/* forward space to end of media */
1460 			error = st_check_eod(st, FALSE, &nmarks, flags);
1461 			if (!error)
1462 				error = st_space(st, 1, SP_EOM, flags);
1463 			break;
1464 		case MTCACHE:	/* enable controller cache */
1465 			st->flags &= ~ST_DONTBUFFER;
1466 			goto try_new_value;
1467 		case MTNOCACHE:	/* disable controller cache */
1468 			st->flags |= ST_DONTBUFFER;
1469 			goto try_new_value;
1470 		case MTERASE:	/* erase volume */
1471 			error = st_erase(st, number, flags);
1472 			break;
1473 		case MTSETBSIZ:	/* Set block size for device */
1474 #ifdef	NOTYET
1475 			if (!(st->flags & ST_NEW_MOUNT)) {
1476 				uprintf("re-mount tape before changing blocksize");
1477 				error = EINVAL;
1478 				break;
1479 			}
1480 #endif
1481 			if (number == 0)
1482 				st->flags &= ~ST_FIXEDBLOCKS;
1483 			else {
1484 				if ((st->blkmin || st->blkmax) &&
1485 				    (number < st->blkmin ||
1486 				    number > st->blkmax)) {
1487 					error = EINVAL;
1488 					break;
1489 				}
1490 				st->flags |= ST_FIXEDBLOCKS;
1491 			}
1492 			st->blksize = number;
1493 			st->flags |= ST_BLOCK_SET;	/*XXX */
1494 			goto try_new_value;
1495 
1496 		case MTSETDNSTY:	/* Set density for device and mode */
1497 			/*
1498 			 * Any number >= 0 and <= 0xff is legal. Numbers
1499 			 * above 0x80 are 'vendor unique'.
1500 			 */
1501 			if (number < 0 || number > 255) {
1502 				error = EINVAL;
1503 				break;
1504 			} else
1505 				st->density = number;
1506 			goto try_new_value;
1507 
1508 		case MTCMPRESS:
1509 			error = st->ops(st, (number == 0) ?
1510 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1511 			    XS_CTL_SILENT);
1512 			break;
1513 
1514 		case MTEWARN:
1515 			if (number)
1516 				st->flags |= ST_EARLYWARN;
1517 			else
1518 				st->flags &= ~ST_EARLYWARN;
1519 			break;
1520 
1521 		default:
1522 			error = EINVAL;
1523 		}
1524 		break;
1525 	}
1526 	case MTIOCIEOT:
1527 	case MTIOCEEOT:
1528 		break;
1529 
1530 	case MTIOCRDSPOS:
1531 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1532 		break;
1533 
1534 	case MTIOCRDHPOS:
1535 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1536 		break;
1537 
1538 	case MTIOCSLOCATE:
1539 		error = st_setpos(st, 0, (u_int32_t *) arg);
1540 		break;
1541 
1542 	case MTIOCHLOCATE:
1543 		error = st_setpos(st, 1, (u_int32_t *) arg);
1544 		break;
1545 
1546 
1547 	default:
1548 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1549 					flag, p);
1550 		break;
1551 	}
1552 	return (error);
1553 /*-----------------------------*/
1554 try_new_value:
1555 	/*
1556 	 * Check that the mode being asked for is aggreeable to the
1557 	 * drive. If not, put it back the way it was.
1558 	 *
1559 	 * If in control mode, we can make (persistent) mode changes
1560 	 * even if no medium is loaded (see st(4)).
1561 	 */
1562 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1563 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1564 		/* put it back as it was */
1565 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1566 		st->density = hold_density;
1567 		st->blksize = hold_blksize;
1568 		if (st->blksize)
1569 			st->flags |= ST_FIXEDBLOCKS;
1570 		else
1571 			st->flags &= ~ST_FIXEDBLOCKS;
1572 		return (error);
1573 	}
1574 	/*
1575 	 * As the drive liked it, if we are setting a new default,
1576 	 * set it into the structures as such.
1577 	 *
1578 	 * The means for deciding this are not finalised yet- but
1579 	 * if the device was opened in Control Mode, the values
1580 	 * are persistent now across mounts.
1581 	 */
1582 	if (STMODE(dev) == CTRL_MODE) {
1583 		switch ((short) (mt->mt_op)) {
1584 		case MTSETBSIZ:
1585 			st->modes[dsty].blksize = st->blksize;
1586 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1587 			break;
1588 		case MTSETDNSTY:
1589 			st->modes[dsty].density = st->density;
1590 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1591 			break;
1592 		}
1593 	}
1594 	return (0);
1595 }
1596 
1597 /*
1598  * Do a synchronous read.
1599  */
1600 int
1601 st_read(st, buf, size, flags)
1602 	struct st_softc *st;
1603 	int size;
1604 	int flags;
1605 	char *buf;
1606 {
1607 	struct scsi_rw_tape cmd;
1608 
1609 	/*
1610 	 * If it's a null transfer, return immediatly
1611 	 */
1612 	if (size == 0)
1613 		return (0);
1614 	memset(&cmd, 0, sizeof(cmd));
1615 	cmd.opcode = READ;
1616 	if (st->flags & ST_FIXEDBLOCKS) {
1617 		cmd.byte2 |= SRW_FIXED;
1618 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1619 		    cmd.len);
1620 	} else
1621 		_lto3b(size, cmd.len);
1622 	return (scsipi_command(st->sc_periph,
1623 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1624 	    (u_char *)buf, size, 0, ST_IO_TIME, NULL, flags | XS_CTL_DATA_IN));
1625 }
1626 
1627 /*
1628  * issue an erase command
1629  */
1630 int
1631 st_erase(st, full, flags)
1632 	struct st_softc *st;
1633 	int full, flags;
1634 {
1635 	int tmo;
1636 	struct scsi_erase cmd;
1637 
1638 	/*
1639 	 * Full erase means set LONG bit in erase command, which asks
1640 	 * the drive to erase the entire unit.  Without this bit, we're
1641 	 * asking the drive to write an erase gap.
1642 	 */
1643 	memset(&cmd, 0, sizeof(cmd));
1644 	cmd.opcode = ERASE;
1645 	if (full) {
1646 		cmd.byte2 = SE_LONG;
1647 		tmo = ST_SPC_TIME;
1648 	} else {
1649 		tmo = ST_IO_TIME;
1650 	}
1651 
1652 	/*
1653 	 * XXX We always do this asynchronously, for now, unless the device
1654 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1655 	 * want to (eventually) to it synchronously?
1656 	 */
1657 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1658 		cmd.byte2 |= SE_IMMED;
1659 
1660 	return (scsipi_command(st->sc_periph,
1661 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1662 	    0, 0, ST_RETRIES, tmo, NULL, flags));
1663 }
1664 
1665 /*
1666  * skip N blocks/filemarks/seq filemarks/eom
1667  */
1668 int
1669 st_space(st, number, what, flags)
1670 	struct st_softc *st;
1671 	u_int what;
1672 	int flags;
1673 	int number;
1674 {
1675 	struct scsi_space cmd;
1676 	int error;
1677 
1678 	switch (what) {
1679 	case SP_BLKS:
1680 		if (st->flags & ST_PER_ACTION) {
1681 			if (number > 0) {
1682 				st->flags &= ~ST_PER_ACTION;
1683 				return (EIO);
1684 			} else if (number < 0) {
1685 				if (st->flags & ST_AT_FILEMARK) {
1686 					/*
1687 					 * Handling of ST_AT_FILEMARK
1688 					 * in st_space will fill in the
1689 					 * right file mark count.
1690 					 */
1691 					error = st_space(st, 0, SP_FILEMARKS,
1692 					    flags);
1693 					if (error)
1694 						return (error);
1695 				}
1696 				if (st->flags & ST_BLANK_READ) {
1697 					st->flags &= ~ST_BLANK_READ;
1698 					return (EIO);
1699 				}
1700 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1701 			}
1702 		}
1703 		break;
1704 	case SP_FILEMARKS:
1705 		if (st->flags & ST_EIO_PENDING) {
1706 			if (number > 0) {
1707 				/* pretend we just discovered the error */
1708 				st->flags &= ~ST_EIO_PENDING;
1709 				return (EIO);
1710 			} else if (number < 0) {
1711 				/* back away from the error */
1712 				st->flags &= ~ST_EIO_PENDING;
1713 			}
1714 		}
1715 		if (st->flags & ST_AT_FILEMARK) {
1716 			st->flags &= ~ST_AT_FILEMARK;
1717 			number--;
1718 		}
1719 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1720 			/* back away from unwritten tape */
1721 			st->flags &= ~ST_BLANK_READ;
1722 			number++;	/* XXX dubious */
1723 		}
1724 		break;
1725 	case SP_EOM:
1726 		if (st->flags & ST_EOM_PENDING) {
1727 			/* we're already there */
1728 			st->flags &= ~ST_EOM_PENDING;
1729 			return (0);
1730 		}
1731 		if (st->flags & ST_EIO_PENDING) {
1732 			/* pretend we just discovered the error */
1733 			st->flags &= ~ST_EIO_PENDING;
1734 			return (EIO);
1735 		}
1736 		if (st->flags & ST_AT_FILEMARK)
1737 			st->flags &= ~ST_AT_FILEMARK;
1738 		break;
1739 	}
1740 	if (number == 0)
1741 		return (0);
1742 
1743 	memset(&cmd, 0, sizeof(cmd));
1744 	cmd.opcode = SPACE;
1745 	cmd.byte2 = what;
1746 	_lto3b(number, cmd.number);
1747 
1748 	st->flags &= ~ST_POSUPDATED;
1749 	st->last_ctl_resid = 0;
1750 	error = scsipi_command(st->sc_periph,
1751 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1752 	    0, 0, 0, ST_SPC_TIME, NULL, flags);
1753 
1754 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1755 		number = number - st->last_ctl_resid;
1756 		if (what == SP_BLKS) {
1757 			if (st->blkno != -1) {
1758 				st->blkno += number;
1759 			}
1760 		} else if (what == SP_FILEMARKS) {
1761 			if (st->fileno != -1) {
1762 				st->fileno += number;
1763 				if (number > 0) {
1764 					st->blkno = 0;
1765 				} else if (number < 0) {
1766 					st->blkno = -1;
1767 				}
1768 			}
1769 		} else if (what == SP_EOM) {
1770 			/*
1771 			 * This loses us relative position.
1772 			 */
1773 			st->fileno = st->blkno = -1;
1774 		}
1775 	}
1776 	return (error);
1777 }
1778 
1779 /*
1780  * write N filemarks
1781  */
1782 int
1783 st_write_filemarks(st, number, flags)
1784 	struct st_softc *st;
1785 	int flags;
1786 	int number;
1787 {
1788 	int error;
1789 	struct scsi_write_filemarks cmd;
1790 
1791 	/*
1792 	 * It's hard to write a negative number of file marks.
1793 	 * Don't try.
1794 	 */
1795 	if (number < 0)
1796 		return (EINVAL);
1797 	switch (number) {
1798 	case 0:		/* really a command to sync the drive's buffers */
1799 		break;
1800 	case 1:
1801 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1802 			st->flags &= ~ST_WRITTEN;
1803 		else
1804 			st->flags |= ST_FM_WRITTEN;
1805 		st->flags &= ~ST_PER_ACTION;
1806 		break;
1807 	default:
1808 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1809 	}
1810 
1811 	memset(&cmd, 0, sizeof(cmd));
1812 	cmd.opcode = WRITE_FILEMARKS;
1813 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1814 		cmd.byte2 = SR_IMMED;
1815 	/*
1816 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1817 	 * WRITE_FILEMARKS is still used to flush the buffer
1818 	 */
1819 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1820 		_lto3b(number, cmd.number);
1821 
1822 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1823 	error = scsipi_command(st->sc_periph,
1824 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1825 	    0, 0, 0, ST_IO_TIME * 4, NULL, flags);
1826 	if (error == 0 && st->fileno != -1) {
1827 		st->fileno += number;
1828 	}
1829 	return (error);
1830 }
1831 
1832 /*
1833  * Make sure the right number of file marks is on tape if the
1834  * tape has been written.  If the position argument is true,
1835  * leave the tape positioned where it was originally.
1836  *
1837  * nmarks returns the number of marks to skip (or, if position
1838  * true, which were skipped) to get back original position.
1839  */
1840 int
1841 st_check_eod(st, position, nmarks, flags)
1842 	struct st_softc *st;
1843 	boolean position;
1844 	int *nmarks;
1845 	int flags;
1846 {
1847 	int error;
1848 
1849 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1850 	default:
1851 		*nmarks = 0;
1852 		return (0);
1853 	case ST_WRITTEN:
1854 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1855 		*nmarks = 1;
1856 		break;
1857 	case ST_WRITTEN | ST_2FM_AT_EOD:
1858 		*nmarks = 2;
1859 	}
1860 	error = st_write_filemarks(st, *nmarks, flags);
1861 	if (position && !error)
1862 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1863 	return (error);
1864 }
1865 
1866 /*
1867  * load/unload/retension
1868  */
1869 int
1870 st_load(st, type, flags)
1871 	struct st_softc *st;
1872 	u_int type;
1873 	int flags;
1874 {
1875 	int error;
1876 	struct scsi_load cmd;
1877 
1878 	if (type != LD_LOAD) {
1879 		int nmarks;
1880 
1881 		error = st_check_eod(st, FALSE, &nmarks, flags);
1882 		if (error) {
1883 			printf("%s: failed to write closing filemarks at "
1884 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1885 			return (error);
1886 		}
1887 	}
1888 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1889 		if (type == LD_LOAD) {
1890 			/*
1891 			 * If we ignore loads, at least we should try a rewind.
1892 			 */
1893 			return st_rewind(st, 0, flags);
1894 		}
1895 		/* otherwise, we should do what's asked of us */
1896 	}
1897 
1898 	memset(&cmd, 0, sizeof(cmd));
1899 	cmd.opcode = LOAD;
1900 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1901 		cmd.byte2 = SR_IMMED;
1902 	cmd.how = type;
1903 
1904 	error = scsipi_command(st->sc_periph,
1905 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1906 	    0, 0, ST_RETRIES, ST_SPC_TIME, NULL, flags);
1907 	if (error) {
1908 		printf("%s: error %d in st_load (op %d)\n",
1909 		    st->sc_dev.dv_xname, error, type);
1910 	}
1911 	return (error);
1912 }
1913 
1914 /*
1915  *  Rewind the device
1916  */
1917 int
1918 st_rewind(st, immediate, flags)
1919 	struct st_softc *st;
1920 	u_int immediate;
1921 	int flags;
1922 {
1923 	struct scsi_rewind cmd;
1924 	int error;
1925 	int nmarks;
1926 
1927 	error = st_check_eod(st, FALSE, &nmarks, flags);
1928 	if (error) {
1929 		printf("%s: failed to write closing filemarks at "
1930 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1931 		return (error);
1932 	}
1933 	st->flags &= ~ST_PER_ACTION;
1934 
1935 	/*
1936 	 * ATAPI tapes always need immediate to be set
1937 	 */
1938 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1939 		immediate = SR_IMMED;
1940 
1941 	memset(&cmd, 0, sizeof(cmd));
1942 	cmd.opcode = REWIND;
1943 	cmd.byte2 = immediate;
1944 
1945 	error = scsipi_command(st->sc_periph,
1946 	    (struct scsipi_generic *)&cmd, sizeof(cmd), 0, 0, ST_RETRIES,
1947 	    immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
1948 	if (error) {
1949 		printf("%s: error %d trying to rewind\n",
1950 		    st->sc_dev.dv_xname, error);
1951 		/* lost position */
1952 		st->fileno = st->blkno = -1;
1953 	} else {
1954 		st->fileno = st->blkno = 0;
1955 	}
1956 	return (error);
1957 }
1958 
1959 int
1960 st_rdpos(st, hard, blkptr)
1961 	struct st_softc *st;
1962 	int hard;
1963 	u_int32_t *blkptr;
1964 {
1965 	int error;
1966 	u_int8_t posdata[20];
1967 	struct scsi_tape_read_position cmd;
1968 
1969 	/*
1970 	 * We try and flush any buffered writes here if we were writing
1971 	 * and we're trying to get hardware block position. It eats
1972 	 * up performance substantially, but I'm wary of drive firmware.
1973 	 *
1974 	 * I think that *logical* block position is probably okay-
1975 	 * but hardware block position might have to wait for data
1976 	 * to hit media to be valid. Caveat Emptor.
1977 	 */
1978 
1979 	if (hard && (st->flags & ST_WRITTEN)) {
1980 		/*
1981 		 * First flush any pending writes...
1982 		 */
1983 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
1984 		/*
1985 		 * The latter case is for 'write protected' tapes
1986 		 * which are too stupid to recognize a zero count
1987 		 * for writing filemarks as a no-op.
1988 		 */
1989 		if (error != 0 && error != EACCES && error != EROFS)
1990 			return (error);
1991 	}
1992 
1993 	memset(&cmd, 0, sizeof(cmd));
1994 	memset(&posdata, 0, sizeof(posdata));
1995 	cmd.opcode = READ_POSITION;
1996 	if (hard)
1997 		cmd.byte1 = 1;
1998 
1999 	error = scsipi_command(st->sc_periph,
2000 	    (struct scsipi_generic *)&cmd, sizeof(cmd), (u_char *)&posdata,
2001 	    sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
2002 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
2003 
2004 	if (error == 0) {
2005 #if	0
2006 		printf("posdata:");
2007 		for (hard = 0; hard < sizeof(posdata); hard++)
2008 			printf("%02x ", posdata[hard] & 0xff);
2009 		printf("\n");
2010 #endif
2011 		if (posdata[0] & 0x4)	/* Block Position Unknown */
2012 			error = EINVAL;
2013 		else
2014 			*blkptr = _4btol(&posdata[4]);
2015 	}
2016 	return (error);
2017 }
2018 
2019 int
2020 st_setpos(st, hard, blkptr)
2021 	struct st_softc *st;
2022 	int hard;
2023 	u_int32_t *blkptr;
2024 {
2025 	int error;
2026 	struct scsi_tape_locate cmd;
2027 
2028 	/*
2029 	 * We used to try and flush any buffered writes here.
2030 	 * Now we push this onto user applications to either
2031 	 * flush the pending writes themselves (via a zero count
2032 	 * WRITE FILEMARKS command) or they can trust their tape
2033 	 * drive to do this correctly for them.
2034 	 *
2035 	 * There are very ugly performance limitations otherwise.
2036 	 */
2037 
2038 	memset(&cmd, 0, sizeof(cmd));
2039 	cmd.opcode = LOCATE;
2040 	if (hard)
2041 		cmd.byte2 = 1 << 2;
2042 	_lto4b(*blkptr, cmd.blkaddr);
2043 	error = scsipi_command(st->sc_periph,
2044 		(struct scsipi_generic *)&cmd, sizeof(cmd),
2045 		NULL, 0, ST_RETRIES, ST_SPC_TIME, NULL, 0);
2046 	/*
2047 	 * Note file && block number position now unknown (if
2048 	 * these things ever start being maintained in this driver)
2049 	 */
2050 	st->fileno = st->blkno = -1;
2051 	return (error);
2052 }
2053 
2054 
2055 /*
2056  * Look at the returned sense and act on the error and determine
2057  * the unix error number to pass back..., 0 (== report no error),
2058  * -1 = retry the operation, -2 continue error processing.
2059  */
2060 int
2061 st_interpret_sense(xs)
2062 	struct scsipi_xfer *xs;
2063 {
2064 	struct scsipi_periph *periph = xs->xs_periph;
2065 	struct scsipi_sense_data *sense = &xs->sense.scsi_sense;
2066 	struct buf *bp = xs->bp;
2067 	struct st_softc *st = (void *)periph->periph_dev;
2068 	int retval = EJUSTRETURN;
2069 	int doprint = ((xs->xs_control & XS_CTL_SILENT) == 0);
2070 	u_int8_t key;
2071 	int32_t info;
2072 
2073 	/*
2074 	 * If it isn't a extended or extended/deferred error, let
2075 	 * the generic code handle it.
2076 	 */
2077 	if ((sense->error_code & SSD_ERRCODE) != 0x70 &&
2078 	    (sense->error_code & SSD_ERRCODE) != 0x71) {	/* DEFFERRED */
2079 		return (retval);
2080 	}
2081 
2082 	if (sense->error_code & SSD_ERRCODE_VALID)
2083 		info = _4btol(sense->info);
2084 	else
2085 		info = (st->flags & ST_FIXEDBLOCKS) ?
2086 		    xs->datalen / st->blksize : xs->datalen;
2087 	key = sense->flags & SSD_KEY;
2088 	st->mt_erreg = key;
2089 	st->asc = sense->add_sense_code;
2090 	st->ascq = sense->add_sense_code_qual;
2091 	st->mt_resid = (short) info;
2092 
2093 	if (key == SKEY_NOT_READY && st->asc == 0x4 && st->ascq == 0x1) {
2094 		/* Not Ready, Logical Unit Is in Process Of Becoming Ready */
2095 		if (!callout_active(&periph->periph_callout))
2096 			scsipi_periph_freeze(periph, 1);
2097 		callout_reset(&periph->periph_callout,
2098 		    hz, scsipi_periph_timed_thaw, periph);
2099 		return (ERESTART);
2100 	}
2101 
2102 	/*
2103 	 * If the device is not open yet, let generic handle
2104 	 */
2105 	if ((periph->periph_flags & PERIPH_OPEN) == 0) {
2106 		return (retval);
2107 	}
2108 
2109 	xs->resid = info;
2110 	if (st->flags & ST_FIXEDBLOCKS) {
2111 		if (bp) {
2112 			xs->resid *= st->blksize;
2113 			st->last_io_resid = xs->resid;
2114 		} else {
2115 			st->last_ctl_resid = xs->resid;
2116 		}
2117 		if (key == SKEY_VOLUME_OVERFLOW) {
2118 			st->flags |= ST_EIO_PENDING;
2119 			if (bp)
2120 				bp->b_resid = xs->resid;
2121 		} else if (sense->flags & SSD_EOM) {
2122 			if ((st->flags & ST_EARLYWARN) == 0)
2123 				st->flags |= ST_EIO_PENDING;
2124 			st->flags |= ST_EOM_PENDING;
2125 			if (bp) {
2126 #if 0
2127 				bp->b_resid = xs->resid;
2128 #else
2129 				/*
2130 				 * Grotesque as it seems, the few times
2131 				 * I've actually seen a non-zero resid,
2132 				 * the tape drive actually lied and had
2133 				 * written all the data!
2134 				 */
2135 				bp->b_resid = 0;
2136 #endif
2137 			}
2138 		}
2139 		if (sense->flags & SSD_FILEMARK) {
2140 			st->flags |= ST_AT_FILEMARK;
2141 			if (bp)
2142 				bp->b_resid = xs->resid;
2143 			if (st->fileno != (daddr_t) -1) {
2144 				st->fileno++;
2145 				st->blkno = 0;
2146 				st->flags |= ST_POSUPDATED;
2147 			}
2148 		}
2149 		if (sense->flags & SSD_ILI) {
2150 			st->flags |= ST_EIO_PENDING;
2151 			if (bp)
2152 				bp->b_resid = xs->resid;
2153 			if (sense->error_code & SSD_ERRCODE_VALID &&
2154 			    (xs->xs_control & XS_CTL_SILENT) == 0)
2155 				printf("%s: block wrong size, %d blocks "
2156 				    "residual\n", st->sc_dev.dv_xname, info);
2157 
2158 			/*
2159 			 * This quirk code helps the drive read
2160 			 * the first tape block, regardless of
2161 			 * format.  That is required for these
2162 			 * drives to return proper MODE SENSE
2163 			 * information.
2164 			 */
2165 			if ((st->quirks & ST_Q_SENSE_HELP) &&
2166 			    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
2167 				st->blksize -= 512;
2168 			else if ((st->flags & ST_POSUPDATED) == 0) {
2169 				if (st->blkno != (daddr_t) -1) {
2170 					st->blkno +=
2171 					    (xs->datalen / st->blksize);
2172 					st->flags |= ST_POSUPDATED;
2173 				}
2174 			}
2175 		}
2176 		/*
2177 		 * If data wanted and no data was transferred, do it immediately
2178 		 */
2179 		if (xs->datalen && xs->resid >= xs->datalen) {
2180 			if (st->flags & ST_EIO_PENDING)
2181 				return (EIO);
2182 			if (st->flags & ST_AT_FILEMARK) {
2183 				if (bp)
2184 					bp->b_resid = xs->resid;
2185 				return (0);
2186 			}
2187 		}
2188 	} else {		/* must be variable mode */
2189 		if (bp) {
2190 			st->last_io_resid = xs->resid;
2191 		} else {
2192 			st->last_ctl_resid = xs->resid;
2193 		}
2194 		if (sense->flags & SSD_EOM) {
2195 			/*
2196 			 * The current semantics of this
2197 			 * driver requires EOM detection
2198 			 * to return EIO unless early
2199 			 * warning detection is enabled
2200 			 * for variable mode (this is always
2201 			 * on for fixed block mode).
2202 			 */
2203 			if (st->flags & ST_EARLYWARN) {
2204 				st->flags |= ST_EOM_PENDING;
2205 				retval = 0;
2206 			} else {
2207 				retval = EIO;
2208 			}
2209 
2210 			/*
2211 			 * If it's an unadorned EOM detection,
2212 			 * suppress printing an error.
2213 			 */
2214 			if (key == SKEY_NO_SENSE) {
2215 				doprint = 0;
2216 			}
2217 		} else if (sense->flags & SSD_FILEMARK) {
2218 			retval = 0;
2219 			if (st->fileno != (daddr_t) -1) {
2220 				st->fileno++;
2221 				st->blkno = 0;
2222 				st->flags |= ST_POSUPDATED;
2223 			}
2224 		} else if (sense->flags & SSD_ILI) {
2225 			if (info < 0) {
2226 				/*
2227 				 * The tape record was bigger than the read
2228 				 * we issued.
2229 				 */
2230 				if ((xs->xs_control & XS_CTL_SILENT) == 0) {
2231 					printf("%s: %d-byte tape record too big"
2232 					    " for %d-byte user buffer\n",
2233 					    st->sc_dev.dv_xname,
2234 					    xs->datalen - info, xs->datalen);
2235 				}
2236 				retval = EIO;
2237 			} else {
2238 				retval = 0;
2239 				if (st->blkno != (daddr_t) -1) {
2240 					st->blkno++;
2241 					st->flags |= ST_POSUPDATED;
2242 				}
2243 			}
2244 		}
2245 		if (bp)
2246 			bp->b_resid = info;
2247 	}
2248 
2249 #ifndef SCSIPI_DEBUG
2250 	if (retval == 0 && key == SKEY_NO_SENSE)
2251 		doprint = 0;
2252 #endif
2253 	if (key == SKEY_BLANK_CHECK) {
2254 		/*
2255 		 * This quirk code helps the drive read the
2256 		 * first tape block, regardless of format.  That
2257 		 * is required for these drives to return proper
2258 		 * MODE SENSE information.
2259 		 */
2260 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2261 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
2262 			/* still starting */
2263 			st->blksize -= 512;
2264 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2265 			st->flags |= ST_BLANK_READ;
2266 			xs->resid = xs->datalen;
2267 			if (bp) {
2268 				bp->b_resid = xs->resid;
2269 				/* return an EOF */
2270 			}
2271 			retval = 0;
2272 			/* lost position */
2273 			st->fileno = st->blkno = -1;
2274 		}
2275 	}
2276 
2277 	/*
2278 	 * If generic sense processing will continue, we should not
2279 	 * print sense info here.
2280 	 */
2281 	if (retval == EJUSTRETURN)
2282 		doprint = 0;
2283 
2284 	if (doprint) {
2285 #ifdef	SCSIVERBOSE
2286 		scsipi_print_sense(xs, 0);
2287 #else
2288 		scsipi_printaddr(periph);
2289 		printf("Sense Key 0x%02x", key);
2290 		if ((sense->error_code & SSD_ERRCODE_VALID) != 0) {
2291 			switch (key) {
2292 			case SKEY_NOT_READY:
2293 			case SKEY_ILLEGAL_REQUEST:
2294 			case SKEY_UNIT_ATTENTION:
2295 			case SKEY_WRITE_PROTECT:
2296 				break;
2297 			case SKEY_VOLUME_OVERFLOW:
2298 			case SKEY_BLANK_CHECK:
2299 				printf(", requested size: %d (decimal)", info);
2300 				break;
2301 			case SKEY_ABORTED_COMMAND:
2302 				if (xs->xs_retries)
2303 					printf(", retrying");
2304 				printf(", cmd 0x%x, info 0x%x",
2305 				    xs->cmd->opcode, info);
2306 				break;
2307 			default:
2308 				printf(", info = %d (decimal)", info);
2309 			}
2310 		}
2311 		if (sense->extra_len != 0) {
2312 			int n;
2313 			printf(", data =");
2314 			for (n = 0; n < sense->extra_len; n++)
2315 				printf(" %02x", sense->cmd_spec_info[n]);
2316 		}
2317 		printf("\n");
2318 #endif
2319 	}
2320 	return (retval);
2321 }
2322 
2323 /*
2324  * The quirk here is that the drive returns some value to st_mode_sense
2325  * incorrectly until the tape has actually passed by the head.
2326  *
2327  * The method is to set the drive to large fixed-block state (user-specified
2328  * density and 1024-byte blocks), then read and rewind to get it to sense the
2329  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2330  * work, as a last resort, try variable- length blocks.  The result will be
2331  * the ability to do an accurate st_mode_sense.
2332  *
2333  * We know we can do a rewind because we just did a load, which implies rewind.
2334  * Rewind seems preferable to space backward if we have a virgin tape.
2335  *
2336  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2337  * error processing, both part of st_interpret_sense.
2338  */
2339 int
2340 st_touch_tape(st)
2341 	struct st_softc *st;
2342 {
2343 	char *buf;
2344 	int readsize;
2345 	int error;
2346 
2347 	buf = malloc(1024, M_TEMP, M_NOWAIT);
2348 	if (buf == NULL)
2349 		return (ENOMEM);
2350 
2351 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
2352 		goto bad;
2353 
2354 	/*
2355 	 * If the block size is already known from the
2356 	 * sense data, use it. Else start probing at 1024.
2357 	 */
2358 	if (st->media_blksize > 0)
2359 		st->blksize = st->media_blksize;
2360 	else
2361 		st->blksize = 1024;
2362 
2363 	do {
2364 		switch (st->blksize) {
2365 		case 512:
2366 		case 1024:
2367 			readsize = st->blksize;
2368 			st->flags |= ST_FIXEDBLOCKS;
2369 			break;
2370 		default:
2371 			readsize = 1;
2372 			st->flags &= ~ST_FIXEDBLOCKS;
2373 		}
2374 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
2375 		    != 0) {
2376 			/*
2377 			 * The device did not agree with the proposed
2378 			 * block size. If we exhausted our options,
2379 			 * return failure, else try another.
2380 			 */
2381 			if (readsize == 1)
2382 				goto bad;
2383 			st->blksize -= 512;
2384 			continue;
2385 		}
2386 		st_read(st, buf, readsize, XS_CTL_SILENT);	/* XXX */
2387 		if ((error = st_rewind(st, 0, 0)) != 0) {
2388 bad:			free(buf, M_TEMP);
2389 			return (error);
2390 		}
2391 	} while (readsize != 1 && readsize > st->blksize);
2392 
2393 	free(buf, M_TEMP);
2394 	return (0);
2395 }
2396 
2397 int
2398 stdump(dev, blkno, va, size)
2399 	dev_t dev;
2400 	daddr_t blkno;
2401 	caddr_t va;
2402 	size_t size;
2403 {
2404 
2405 	/* Not implemented. */
2406 	return (ENXIO);
2407 }
2408