xref: /netbsd-src/sys/dev/scsipi/st.c (revision de1dfb1250df962f1ff3a011772cf58e605aed11)
1 /*	$NetBSD: st.c,v 1.166 2004/09/09 19:35:33 bouyer Exp $ */
2 
3 /*-
4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Charles M. Hannum.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Originally written by Julian Elischer (julian@tfs.com)
41  * for TRW Financial Systems for use under the MACH(2.5) operating system.
42  *
43  * TRW Financial Systems, in accordance with their agreement with Carnegie
44  * Mellon University, makes this software available to CMU to distribute
45  * or use in any manner that they see fit as long as this message is kept with
46  * the software. For this reason TFS also grants any other persons or
47  * organisations permission to use or modify this software.
48  *
49  * TFS supplies this software to be publicly redistributed
50  * on the understanding that TFS is not responsible for the correct
51  * functioning of this software in any circumstances.
52  *
53  * Ported to run under 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
54  * major changes by Julian Elischer (julian@jules.dialix.oz.au) May 1993
55  *
56  * A lot of rewhacking done by mjacob (mjacob@nas.nasa.gov).
57  */
58 
59 #include <sys/cdefs.h>
60 __KERNEL_RCSID(0, "$NetBSD: st.c,v 1.166 2004/09/09 19:35:33 bouyer Exp $");
61 
62 #include "opt_scsi.h"
63 
64 #include <sys/param.h>
65 #include <sys/systm.h>
66 #include <sys/fcntl.h>
67 #include <sys/errno.h>
68 #include <sys/ioctl.h>
69 #include <sys/malloc.h>
70 #include <sys/buf.h>
71 #include <sys/proc.h>
72 #include <sys/user.h>
73 #include <sys/mtio.h>
74 #include <sys/device.h>
75 #include <sys/conf.h>
76 #include <sys/kernel.h>
77 #include <sys/vnode.h>
78 
79 #include <dev/scsipi/scsi_all.h>
80 #include <dev/scsipi/scsi_tape.h>
81 #include <dev/scsipi/stvar.h>
82 #include <dev/scsipi/scsipi_base.h>
83 
84 /* Defines for device specific stuff */
85 #define DEF_FIXED_BSIZE  512
86 
87 #define STMODE(z)	( minor(z)       & 0x03)
88 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
89 #define STUNIT(z)	((minor(z) >> 4)       )
90 #define STNMINOR	16
91 
92 #define NORMAL_MODE	0
93 #define NOREW_MODE	1
94 #define EJECT_MODE	2
95 #define CTRL_MODE	3
96 
97 #define	FALSE		0
98 #define	TRUE		1
99 
100 #ifndef		ST_MOUNT_DELAY
101 #define		ST_MOUNT_DELAY		0
102 #endif
103 
104 static dev_type_open(stopen);
105 static dev_type_close(stclose);
106 static dev_type_read(stread);
107 static dev_type_write(stwrite);
108 static dev_type_ioctl(stioctl);
109 static dev_type_strategy(ststrategy);
110 static dev_type_dump(stdump);
111 
112 const struct bdevsw st_bdevsw = {
113 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
114 };
115 
116 const struct cdevsw st_cdevsw = {
117 	stopen, stclose, stread, stwrite, stioctl,
118 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
119 };
120 
121 /*
122  * Define various devices that we know mis-behave in some way,
123  * and note how they are bad, so we can correct for them
124  */
125 
126 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
127 	{{T_SEQUENTIAL, T_REMOV,
128 	 "        ", "                ", "    "}, {0, 0, {
129 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
130 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
131 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
132 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
133 	}}},
134 	{{T_SEQUENTIAL, T_REMOV,
135 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
136 		{0, 0, 0},				/* minor 0-3 */
137 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
138 		{0, 0, QIC_150},			/* minor 8-11 */
139 		{0, 0, QIC_120}				/* minor 12-15 */
140 	}}},
141  	{{T_SEQUENTIAL, T_REMOV,
142  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
143 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
144 		{0, 0, QIC_525},			/* minor 4-7 */
145 		{0, 0, QIC_150},			/* minor 8-11 */
146 		{0, 0, QIC_120}				/* minor 12-15 */
147 	}}},
148 	{{T_SEQUENTIAL, T_REMOV,
149 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
150 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
151 		{0, 0, 0},				/* minor 4-7 */
152 		{0, 0, 0},				/* minor 8-11 */
153 		{0, 0, 0}				/* minor 12-15 */
154 	}}},
155 	/*
156 	 * lacking a manual for the 4200, it's not clear what the
157 	 * specific density codes should be- the device is a 2.5GB
158 	 * capable QIC drive, those density codes aren't readily
159 	 * availabel. The 'default' will just have to do.
160 	 */
161  	{{T_SEQUENTIAL, T_REMOV,
162  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
163 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
164 		{0, 0, QIC_525},			/* minor 4-7 */
165 		{0, 0, QIC_150},			/* minor 8-11 */
166 		{0, 0, QIC_120}				/* minor 12-15 */
167 	}}},
168 	/*
169 	 * At least -005 and -007 need this.  I'll assume they all do unless I
170 	 * hear otherwise.  - mycroft, 31MAR1994
171 	 */
172 	{{T_SEQUENTIAL, T_REMOV,
173 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
174 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
175 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
176 		{0, 0, QIC_150},			/* minor 8-11 */
177 		{0, 0, QIC_120}				/* minor 12-15 */
178 	}}},
179 	/*
180 	 * One user reports that this works for his tape drive.  It probably
181 	 * needs more work.  - mycroft, 09APR1994
182 	 */
183 	{{T_SEQUENTIAL, T_REMOV,
184 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
185 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
186 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
187 		{0, 0, QIC_150},			/* minor 8-11 */
188 		{0, 0, QIC_120}				/* minor 12-15 */
189 	}}},
190 	{{T_SEQUENTIAL, T_REMOV,
191 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
192 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
193 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
194 		{0, 0, QIC_150},			/* minor 8-11 */
195 		{0, 0, QIC_120}				/* minor 12-15 */
196 	}}},
197 	{{T_SEQUENTIAL, T_REMOV,
198 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
199 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
200 		{0, 0, QIC_150},			/* minor 4-7 */
201 		{0, 0, QIC_120},			/* minor 8-11 */
202 		{0, 0, QIC_24}				/* minor 12-15 */
203 	}}},
204 	{{T_SEQUENTIAL, T_REMOV,
205 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
206 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
207 		{0, 0, QIC_150},			/* minor 4-7 */
208 		{0, 0, QIC_120},			/* minor 8-11 */
209 		{0, 0, QIC_24}				/* minor 12-15 */
210 	}}},
211 	{{T_SEQUENTIAL, T_REMOV,
212 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
213 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
214 		{0, 0, QIC_11},				/* minor 4-7 */
215 		{0, 0, QIC_24},				/* minor 8-11 */
216 		{0, 0, QIC_24}				/* minor 12-15 */
217 	}}},
218 	{{T_SEQUENTIAL, T_REMOV,
219 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
220 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
221 		{0, 0, QIC_24},				/* minor 4-7 */
222 		{0, 0, QIC_120},			/* minor 8-11 */
223 		{0, 0, QIC_150}				/* minor 12-15 */
224 	}}},
225 	{{T_SEQUENTIAL, T_REMOV,
226 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
227 		{0, 0, 0},				/* minor 0-3 */
228 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
229 		{0, 0, QIC_150},			/* minor 8-11 */
230 		{0, 0, QIC_120}				/* minor 12-15 */
231 	}}},
232 	{{T_SEQUENTIAL, T_REMOV,
233 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
234 		{0, 0, 0},				/* minor 0-3 */
235 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
236 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
237 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
238 	}}},
239 	{{T_SEQUENTIAL, T_REMOV,
240 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
241 		{0, 0, 0},				/* minor 0-3 */
242 		{0, 0, 0},				/* minor 4-7 */
243 		{0, 0, 0},				/* minor 8-11 */
244 		{0, 0, 0}				/* minor 12-15 */
245 	}}},
246 	{{T_SEQUENTIAL, T_REMOV,
247 	 "STK",      "9490",             ""},
248 				{ST_Q_FORCE_BLKSIZE, 0, {
249 		{0, 0, 0},				/* minor 0-3 */
250 		{0, 0, 0},				/* minor 4-7 */
251 		{0, 0, 0},				/* minor 8-11 */
252 		{0, 0, 0}				/* minor 12-15 */
253 	}}},
254 	{{T_SEQUENTIAL, T_REMOV,
255 	 "STK",      "SD-3",             ""},
256 				{ST_Q_FORCE_BLKSIZE, 0, {
257 		{0, 0, 0},				/* minor 0-3 */
258 		{0, 0, 0},				/* minor 4-7 */
259 		{0, 0, 0},				/* minor 8-11 */
260 		{0, 0, 0}				/* minor 12-15 */
261 	}}},
262 	{{T_SEQUENTIAL, T_REMOV,
263 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
264 		{0, 0, 0},				/* minor 0-3 */
265 		{0, 0, 0},				/* minor 4-7 */
266 		{0, 0, 0},				/* minor 8-11 */
267 		{0, 0, 0}				/* minor 12-15 */
268 	}}},
269 	{{T_SEQUENTIAL, T_REMOV,
270 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
271 		{0, 0, QIC_3095},			/* minor 0-3 */
272 		{0, 0, QIC_3095},			/* minor 4-7 */
273 		{0, 0, QIC_3095},			/* minor 8-11 */
274 		{0, 0, QIC_3095},			/* minor 12-15 */
275 	}}},
276 #if 0
277 	{{T_SEQUENTIAL, T_REMOV,
278 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
279 		{0, 0, 0},				/* minor 0-3 */
280 		{0, 0, 0},				/* minor 4-7 */
281 		{0, 0, 0},				/* minor 8-11 */
282 		{0, 0, 0}				/* minor 12-15 */
283 	}}},
284 #endif
285 	{{T_SEQUENTIAL, T_REMOV,
286 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
287 		{0, 0, 0},			        /* minor 0-3 */
288 		{0, 0, 0},			        /* minor 4-7 */
289 		{0, 0, 0},			        /* minor 8-11 */
290 		{0, 0, 0}			        /* minor 12-15 */
291 	}}},
292 	{{T_SEQUENTIAL, T_REMOV,
293 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
294 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
295 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
296 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
297 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
298 	}}},
299 	{{T_SEQUENTIAL, T_REMOV,
300 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
301 		{0, 0, 0},                              /* minor 0-3 */
302 		{0, 0, 0},                              /* minor 4-7 */
303 		{0, 0, 0},                              /* minor 8-11 */
304 		{0, 0, 0}                               /* minor 12-15 */
305 	}}},
306 	{{T_SEQUENTIAL, T_REMOV,
307 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
308 		{0, 0, 0},			       /* minor 0-3 */
309 		{0, 0, 0},			       /* minor 4-7 */
310 		{0, 0, 0},			       /* minor 8-11 */
311 		{0, 0, 0}			       /* minor 12-15 */
312 	}}},
313 };
314 
315 #define NOEJECT 0
316 #define EJECT 1
317 
318 static void	st_identify_drive(struct st_softc *,
319 		    struct scsipi_inquiry_pattern *);
320 static void	st_loadquirks(struct st_softc *);
321 static int	st_mount_tape(dev_t, int);
322 static void	st_unmount(struct st_softc *, boolean);
323 static int	st_decide_mode(struct st_softc *, boolean);
324 static void	ststart(struct scsipi_periph *);
325 static void	strestart(void *);
326 static void	stdone(struct scsipi_xfer *);
327 static int	st_read(struct st_softc *, char *, int, int);
328 static int	st_space(struct st_softc *, int, u_int, int);
329 static int	st_write_filemarks(struct st_softc *, int, int);
330 static int	st_check_eod(struct st_softc *, boolean, int *, int);
331 static int	st_load(struct st_softc *, u_int, int);
332 static int	st_rewind(struct st_softc *, u_int, int);
333 static int	st_interpret_sense(struct scsipi_xfer *);
334 static int	st_touch_tape(struct st_softc *);
335 static int	st_erase(struct st_softc *, int full, int flags);
336 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
337 static int	st_setpos(struct st_softc *, int, u_int32_t *);
338 
339 static const struct scsipi_periphsw st_switch = {
340 	st_interpret_sense,
341 	ststart,
342 	NULL,
343 	stdone
344 };
345 
346 #if	defined(ST_ENABLE_EARLYWARN)
347 #define	ST_INIT_FLAGS	ST_EARLYWARN
348 #else
349 #define	ST_INIT_FLAGS	0
350 #endif
351 
352 /*
353  * The routine called by the low level scsi routine when it discovers
354  * A device suitable for this driver
355  */
356 void
357 stattach(struct device *parent, struct st_softc *st, void *aux)
358 {
359 	struct scsipibus_attach_args *sa = aux;
360 	struct scsipi_periph *periph = sa->sa_periph;
361 
362 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
363 
364 	/*
365 	 * Store information needed to contact our base driver
366 	 */
367 	st->sc_periph = periph;
368 	periph->periph_dev = &st->sc_dev;
369 	periph->periph_switch = &st_switch;
370 
371 	/*
372 	 * Set initial flags
373 	 */
374 
375 	st->flags = ST_INIT_FLAGS;
376 
377 	/*
378 	 * Set up the buf queue for this device
379 	 */
380 	bufq_alloc(&st->buf_queue, BUFQ_FCFS);
381 
382 	callout_init(&st->sc_callout);
383 
384 	/*
385 	 * Check if the drive is a known criminal and take
386 	 * Any steps needed to bring it into line
387 	 */
388 	st_identify_drive(st, &sa->sa_inqbuf);
389 	/*
390 	 * Use the subdriver to request information regarding the drive.
391 	 */
392 	printf("\n");
393 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
394 	if (scsipi_test_unit_ready(periph,
395 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
396 	    st->ops(st, ST_OPS_MODESENSE,
397 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
398 		printf("drive empty\n");
399 	else {
400 		printf("density code %d, ", st->media_density);
401 		if (st->media_blksize > 0)
402 			printf("%d-byte", st->media_blksize);
403 		else
404 			printf("variable");
405 		printf(" blocks, write-%s\n",
406 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
407 	}
408 
409 #if NRND > 0
410 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
411 			  RND_TYPE_TAPE, 0);
412 #endif
413 }
414 
415 int
416 stactivate(struct device *self, enum devact act)
417 {
418 	int rv = 0;
419 
420 	switch (act) {
421 	case DVACT_ACTIVATE:
422 		rv = EOPNOTSUPP;
423 		break;
424 
425 	case DVACT_DEACTIVATE:
426 		/*
427 		 * Nothing to do; we key off the device's DVF_ACTIVE.
428 		 */
429 		break;
430 	}
431 	return (rv);
432 }
433 
434 int
435 stdetach(struct device *self, int flags)
436 {
437 	struct st_softc *st = (struct st_softc *)self;
438 	struct buf *bp;
439 	int s, bmaj, cmaj, mn;
440 
441 	/* locate the major number */
442 	bmaj = bdevsw_lookup_major(&st_bdevsw);
443 	cmaj = cdevsw_lookup_major(&st_cdevsw);
444 
445 	/* kill any pending restart */
446 	callout_stop(&st->sc_callout);
447 
448 	s = splbio();
449 
450 	/* Kill off any queued buffers. */
451 	while ((bp = BUFQ_GET(&st->buf_queue)) != NULL) {
452 		bp->b_error = EIO;
453 		bp->b_flags |= B_ERROR;
454 		bp->b_resid = bp->b_bcount;
455 		biodone(bp);
456 	}
457 
458 	bufq_free(&st->buf_queue);
459 
460 	/* Kill off any pending commands. */
461 	scsipi_kill_pending(st->sc_periph);
462 
463 	splx(s);
464 
465 	/* Nuke the vnodes for any open instances */
466 	mn = STUNIT(self->dv_unit);
467 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
468 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
469 
470 
471 #if NRND > 0
472 	/* Unhook the entropy source. */
473 	rnd_detach_source(&st->rnd_source);
474 #endif
475 
476 	return (0);
477 }
478 
479 /*
480  * Use the inquiry routine in 'scsi_base' to get drive info so we can
481  * Further tailor our behaviour.
482  */
483 static void
484 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
485 {
486 	struct st_quirk_inquiry_pattern *finger;
487 	int priority;
488 
489 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
490 	    (caddr_t)st_quirk_patterns,
491 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
492 	    sizeof(st_quirk_patterns[0]), &priority);
493 	if (priority != 0) {
494 		st->quirkdata = &finger->quirkdata;
495 		st->drive_quirks = finger->quirkdata.quirks;
496 		st->quirks = finger->quirkdata.quirks;	/* start value */
497 		st->page_0_size = finger->quirkdata.page_0_size;
498 		st_loadquirks(st);
499 	}
500 }
501 
502 /*
503  * initialise the subdevices to the default (QUIRK) state.
504  * this will remove any setting made by the system operator or previous
505  * operations.
506  */
507 static void
508 st_loadquirks(struct st_softc *st)
509 {
510 	int i;
511 	struct	modes *mode;
512 	struct	modes *mode2;
513 
514 	mode = st->quirkdata->modes;
515 	mode2 = st->modes;
516 	for (i = 0; i < 4; i++) {
517 		memset(mode2, 0, sizeof(struct modes));
518 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
519 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
520 		    DENSITY_SET_BY_USER);
521 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
522 			mode2->blksize = mode->blksize;
523 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
524 		}
525 		if (mode->density) {
526 			mode2->density = mode->density;
527 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
528 		}
529 		mode2->quirks |= mode->quirks;
530 		mode++;
531 		mode2++;
532 	}
533 }
534 
535 /*
536  * open the device.
537  */
538 static int
539 stopen(dev_t dev, int flags, int mode, struct proc *p)
540 {
541 	u_int stmode, dsty;
542 	int error, sflags, unit, tries, ntries;
543 	struct st_softc *st;
544 	struct scsipi_periph *periph;
545 	struct scsipi_adapter *adapt;
546 
547 	unit = STUNIT(dev);
548 	if (unit >= st_cd.cd_ndevs)
549 		return (ENXIO);
550 	st = st_cd.cd_devs[unit];
551 	if (st == NULL)
552 		return (ENXIO);
553 
554 	stmode = STMODE(dev);
555 	dsty = STDSTY(dev);
556 
557 	periph = st->sc_periph;
558 	adapt = periph->periph_channel->chan_adapter;
559 
560 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
561 	    unit, st_cd.cd_ndevs));
562 
563 
564 	/*
565 	 * Only allow one at a time
566 	 */
567 	if (periph->periph_flags & PERIPH_OPEN) {
568 		printf("%s: already open\n", st->sc_dev.dv_xname);
569 		return (EBUSY);
570 	}
571 
572 	if ((error = scsipi_adapter_addref(adapt)) != 0)
573 		return (error);
574 
575 	/*
576 	 * clear any latched errors.
577 	 */
578 	st->mt_resid = 0;
579 	st->mt_erreg = 0;
580 	st->asc = 0;
581 	st->ascq = 0;
582 
583 	/*
584 	 * Catch any unit attention errors. Be silent about this
585 	 * unless we're already mounted. We ignore media change
586 	 * if we're in control mode or not mounted yet.
587 	 */
588 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
589 #ifdef SCSIDEBUG
590 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
591 #else
592 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
593 #endif
594 	} else
595 		sflags = 0;
596 
597 	/*
598 	 * If we're already mounted or we aren't configured for
599 	 * a mount delay, only try a test unit ready once. Otherwise,
600 	 * try up to ST_MOUNT_DELAY times with a rest interval of
601 	 * one second between each try.
602 	 */
603 
604 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
605 		ntries = 1;
606 	} else {
607 		ntries = ST_MOUNT_DELAY;
608 	}
609 
610 	for (error = tries = 0; tries < ntries; tries++) {
611 		int slpintr, oflags;
612 
613 		/*
614 		 * If we had no error, or we're opening the control mode
615 		 * device, we jump out right away.
616 		 */
617 
618 		error = scsipi_test_unit_ready(periph, sflags);
619 		if (error == 0 || stmode == CTRL_MODE) {
620 			break;
621 		}
622 
623 		/*
624 		 * We had an error.
625 		 *
626 		 * If we're already mounted or we aren't configured for
627 		 * a mount delay, or the error isn't a NOT READY error,
628 		 * skip to the error exit now.
629 		 */
630 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
631 		    (st->mt_key != SKEY_NOT_READY)) {
632 			goto bad;
633 		}
634 
635 		/*
636 		 * clear any latched errors.
637 		 */
638 		st->mt_resid = 0;
639 		st->mt_erreg = 0;
640 		st->asc = 0;
641 		st->ascq = 0;
642 
643 		/*
644 		 * Fake that we have the device open so
645 		 * we block other apps from getting in.
646 		 */
647 
648 		oflags = periph->periph_flags;
649 		periph->periph_flags |= PERIPH_OPEN;
650 
651 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
652 
653 		periph->periph_flags = oflags;	/* restore flags */
654 		if (slpintr) {
655 			goto bad;
656 		}
657 	}
658 
659 
660 	/*
661 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
662 	 * been opened to set defaults and perform other, usually non-I/O
663 	 * related, operations. In this case, do a quick check to see
664 	 * whether the unit actually had a tape loaded (this will be known
665 	 * as to whether or not we got a NOT READY for the above
666 	 * unit attention). If a tape is there, go do a mount sequence.
667 	 */
668 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
669 		periph->periph_flags |= PERIPH_OPEN;
670 		return (0);
671 	}
672 
673 	/*
674 	 * If we get this far and had an error set, that means we failed
675 	 * to pass the 'test unit ready' test for the non-controlmode device,
676 	 * so we bounce the open.
677 	 */
678 
679 	if (error)
680 		return (error);
681 
682 	/*
683 	 * Else, we're now committed to saying we're open.
684 	 */
685 
686 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
687 
688 	/*
689 	 * If it's a different mode, or if the media has been
690 	 * invalidated, unmount the tape from the previous
691 	 * session but continue with open processing
692 	 */
693 	if (st->last_dsty != dsty ||
694 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
695 		st_unmount(st, NOEJECT);
696 
697 	/*
698 	 * If we are not mounted, then we should start a new
699 	 * mount session.
700 	 */
701 	if (!(st->flags & ST_MOUNTED)) {
702 		if ((error = st_mount_tape(dev, flags)) != 0)
703 			goto bad;
704 		st->last_dsty = dsty;
705 	}
706 	if (!(st->quirks & ST_Q_NOPREVENT)) {
707 		scsipi_prevent(periph, PR_PREVENT,
708 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
709 	}
710 
711 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
712 	return (0);
713 
714 bad:
715 	st_unmount(st, NOEJECT);
716 	scsipi_adapter_delref(adapt);
717 	periph->periph_flags &= ~PERIPH_OPEN;
718 	return (error);
719 }
720 
721 /*
722  * close the device.. only called if we are the LAST
723  * occurence of an open device
724  */
725 static int
726 stclose(dev_t dev, int flags, int mode, struct proc *p)
727 {
728 	int stxx, error = 0;
729 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
730 	struct scsipi_periph *periph = st->sc_periph;
731 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
732 
733 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
734 
735 	/*
736 	 * Make sure that a tape opened in write-only mode will have
737 	 * file marks written on it when closed, even if not written to.
738 	 *
739 	 * This is for SUN compatibility. Actually, the Sun way of
740 	 * things is to:
741 	 *
742 	 *	only write filemarks if there are fmks to be written and
743 	 *   		- open for write (possibly read/write)
744 	 *		- the last operation was a write
745 	 * 	or:
746 	 *		- opened for wronly
747 	 *		- no data was written (including filemarks)
748 	 */
749 
750 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
751 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
752 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
753 		int nm;
754 		error = st_check_eod(st, FALSE, &nm, 0);
755 	}
756 
757 	/*
758 	 * Allow robots to eject tape if needed.
759 	 */
760 	scsipi_prevent(periph, PR_ALLOW,
761 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
762 
763 	switch (STMODE(dev)) {
764 	case NORMAL_MODE:
765 		st_unmount(st, NOEJECT);
766 		break;
767 	case NOREW_MODE:
768 	case CTRL_MODE:
769 		/*
770 		 * Leave mounted unless media seems to have been removed.
771 		 *
772 		 * Otherwise, if we're to terminate a tape with more than one
773 		 * filemark [ and because we're not rewinding here ], backspace
774 		 * one filemark so that later appends will see an unbroken
775 		 * sequence of:
776 		 *
777 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
778 		 */
779 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
780 			st_unmount(st, NOEJECT);
781 		} else if (error == 0) {
782 			/*
783 			 * ST_WRITTEN was preserved from above.
784 			 *
785 			 * All we need to know here is:
786 			 *
787 			 *	Were we writing this tape and was the last
788 			 *	operation a write?
789 			 *
790 			 *	Are there supposed to be 2FM at EOD?
791 			 *
792 			 * If both statements are true, then we backspace
793 			 * one filemark.
794 			 */
795 			stxx |= (st->flags & ST_2FM_AT_EOD);
796 			if ((flags & FWRITE) != 0 &&
797 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
798 				error = st_space(st, -1, SP_FILEMARKS, 0);
799 			}
800 		}
801 		break;
802 	case EJECT_MODE:
803 		st_unmount(st, EJECT);
804 		break;
805 	}
806 
807 	scsipi_wait_drain(periph);
808 
809 	scsipi_adapter_delref(adapt);
810 	periph->periph_flags &= ~PERIPH_OPEN;
811 
812 	return (error);
813 }
814 
815 /*
816  * Start a new mount session.
817  * Copy in all the default parameters from the selected device mode.
818  * and try guess any that seem to be defaulted.
819  */
820 static int
821 st_mount_tape(dev_t dev, int flags)
822 {
823 	int unit;
824 	u_int dsty;
825 	struct st_softc *st;
826 	struct scsipi_periph *periph;
827 	int error = 0;
828 
829 	unit = STUNIT(dev);
830 	dsty = STDSTY(dev);
831 	st = st_cd.cd_devs[unit];
832 	periph = st->sc_periph;
833 
834 	if (st->flags & ST_MOUNTED)
835 		return (0);
836 
837 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
838 	st->flags |= ST_NEW_MOUNT;
839 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
840 	/*
841 	 * If the media is new, then make sure we give it a chance to
842 	 * to do a 'load' instruction.  (We assume it is new.)
843 	 */
844 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
845 		return (error);
846 	/*
847 	 * Throw another dummy instruction to catch
848 	 * 'Unit attention' errors. Many drives give
849 	 * these after doing a Load instruction (with
850 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
851 	 */
852 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
853 
854 	/*
855 	 * Some devices can't tell you much until they have been
856 	 * asked to look at the media. This quirk does this.
857 	 */
858 	if (st->quirks & ST_Q_SENSE_HELP)
859 		if ((error = st_touch_tape(st)) != 0)
860 			return (error);
861 	/*
862 	 * Load the physical device parameters
863 	 * loads: blkmin, blkmax
864 	 */
865 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
866 		return (error);
867 	/*
868 	 * Load the media dependent parameters
869 	 * includes: media_blksize,media_density,numblks
870 	 * As we have a tape in, it should be reflected here.
871 	 * If not you may need the "quirk" above.
872 	 */
873 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
874 		return (error);
875 	/*
876 	 * If we have gained a permanent density from somewhere,
877 	 * then use it in preference to the one supplied by
878 	 * default by the driver.
879 	 */
880 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
881 		st->density = st->modes[dsty].density;
882 	else
883 		st->density = st->media_density;
884 	/*
885 	 * If we have gained a permanent blocksize
886 	 * then use it in preference to the one supplied by
887 	 * default by the driver.
888 	 */
889 	st->flags &= ~ST_FIXEDBLOCKS;
890 	if (st->modeflags[dsty] &
891 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
892 		st->blksize = st->modes[dsty].blksize;
893 		if (st->blksize)
894 			st->flags |= ST_FIXEDBLOCKS;
895 	} else {
896 		if ((error = st_decide_mode(st, FALSE)) != 0)
897 			return (error);
898 	}
899 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
900 		/* ATAPI will return ENODEV for this, and this may be OK */
901 		if (error != ENODEV) {
902 			printf("%s: cannot set selected mode\n",
903 			    st->sc_dev.dv_xname);
904 			return (error);
905 		}
906 	}
907 	st->flags &= ~ST_NEW_MOUNT;
908 	st->flags |= ST_MOUNTED;
909 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
910 	st->blkno = st->fileno = (daddr_t) 0;
911 	return (0);
912 }
913 
914 /*
915  * End the present mount session.
916  * Rewind, and optionally eject the tape.
917  * Reset various flags to indicate that all new
918  * operations require another mount operation
919  */
920 static void
921 st_unmount(struct st_softc *st, boolean eject)
922 {
923 	struct scsipi_periph *periph = st->sc_periph;
924 	int nmarks;
925 
926 	if ((st->flags & ST_MOUNTED) == 0)
927 		return;
928 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
929 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
930 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
931 
932 	/*
933 	 * Section 9.3.3 of the SCSI specs states that a device shall return
934 	 * the density value specified in the last succesfull MODE SELECT
935 	 * after an unload operation, in case it is not able to
936 	 * automatically determine the density of the new medium.
937 	 *
938 	 * So we instruct the device to use the default density, which will
939 	 * prevent the use of stale density values (in particular,
940 	 * in st_touch_tape().
941 	 */
942 	st->density = 0;
943 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
944 		printf("%s: WARNING: cannot revert to default density\n",
945 			st->sc_dev.dv_xname);
946 	}
947 
948 	if (eject) {
949 		if (!(st->quirks & ST_Q_NOPREVENT)) {
950 			scsipi_prevent(periph, PR_ALLOW,
951 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
952 			    XS_CTL_IGNORE_NOT_READY);
953 		}
954 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
955 		st->blkno = st->fileno = (daddr_t) -1;
956 	} else {
957 		st->blkno = st->fileno = (daddr_t) 0;
958 	}
959 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
960 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
961 }
962 
963 /*
964  * Given all we know about the device, media, mode, 'quirks' and
965  * initial operation, make a decision as to how we should be set
966  * to run (regarding blocking and EOD marks)
967  */
968 int
969 st_decide_mode(struct st_softc *st, boolean first_read)
970 {
971 
972 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
973 
974 	/*
975 	 * If the drive can only handle fixed-length blocks and only at
976 	 * one size, perhaps we should just do that.
977 	 */
978 	if (st->blkmin && (st->blkmin == st->blkmax)) {
979 		st->flags |= ST_FIXEDBLOCKS;
980 		st->blksize = st->blkmin;
981 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
982 		    ("blkmin == blkmax of %d\n", st->blkmin));
983 		goto done;
984 	}
985 	/*
986 	 * If the tape density mandates (or even suggests) use of fixed
987 	 * or variable-length blocks, comply.
988 	 */
989 	switch (st->density) {
990 	case HALFINCH_800:
991 	case HALFINCH_1600:
992 	case HALFINCH_6250:
993 	case DDS:
994 		st->flags &= ~ST_FIXEDBLOCKS;
995 		st->blksize = 0;
996 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
997 		    ("density specified variable\n"));
998 		goto done;
999 	case QIC_11:
1000 	case QIC_24:
1001 	case QIC_120:
1002 	case QIC_150:
1003 	case QIC_525:
1004 	case QIC_1320:
1005 	case QIC_3095:
1006 	case QIC_3220:
1007 		st->flags |= ST_FIXEDBLOCKS;
1008 		if (st->media_blksize > 0)
1009 			st->blksize = st->media_blksize;
1010 		else
1011 			st->blksize = DEF_FIXED_BSIZE;
1012 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1013 		    ("density specified fixed\n"));
1014 		goto done;
1015 	}
1016 	/*
1017 	 * If we're about to read the tape, perhaps we should choose
1018 	 * fixed or variable-length blocks and block size according to
1019 	 * what the drive found on the tape.
1020 	 */
1021 	if (first_read &&
1022 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1023 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1024 	    (st->media_blksize == 1024))) {
1025 		if (st->media_blksize > 0)
1026 			st->flags |= ST_FIXEDBLOCKS;
1027 		else
1028 			st->flags &= ~ST_FIXEDBLOCKS;
1029 		st->blksize = st->media_blksize;
1030 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1031 		    ("Used media_blksize of %d\n", st->media_blksize));
1032 		goto done;
1033 	}
1034 	/*
1035 	 * We're getting no hints from any direction.  Choose variable-
1036 	 * length blocks arbitrarily.
1037 	 */
1038 	st->flags &= ~ST_FIXEDBLOCKS;
1039 	st->blksize = 0;
1040 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1041 	    ("Give up and default to variable mode\n"));
1042 
1043 done:
1044 	/*
1045 	 * Decide whether or not to write two file marks to signify end-
1046 	 * of-data.  Make the decision as a function of density.  If
1047 	 * the decision is not to use a second file mark, the SCSI BLANK
1048 	 * CHECK condition code will be recognized as end-of-data when
1049 	 * first read.
1050 	 * (I think this should be a by-product of fixed/variable..julian)
1051 	 */
1052 	switch (st->density) {
1053 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1054 	case QIC_11:
1055 	case QIC_24:
1056 	case QIC_120:
1057 	case QIC_150:
1058 	case QIC_525:
1059 	case QIC_1320:
1060 	case QIC_3095:
1061 	case QIC_3220:
1062 		st->flags &= ~ST_2FM_AT_EOD;
1063 		break;
1064 	default:
1065 		st->flags |= ST_2FM_AT_EOD;
1066 	}
1067 	return (0);
1068 }
1069 
1070 /*
1071  * Actually translate the requested transfer into
1072  * one the physical driver can understand
1073  * The transfer is described by a buf and will include
1074  * only one physical transfer.
1075  */
1076 static void
1077 ststrategy(struct buf *bp)
1078 {
1079 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1080 	int s;
1081 
1082 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1083 	    ("ststrategy %ld bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
1084 	/*
1085 	 * If it's a null transfer, return immediatly
1086 	 */
1087 	if (bp->b_bcount == 0)
1088 		goto done;
1089 
1090 	/* If offset is negative, error */
1091 	if (bp->b_blkno < 0) {
1092 		bp->b_error = EINVAL;
1093 		goto bad;
1094 	}
1095 
1096 	/*
1097 	 * Odd sized request on fixed drives are verboten
1098 	 */
1099 	if (st->flags & ST_FIXEDBLOCKS) {
1100 		if (bp->b_bcount % st->blksize) {
1101 			printf("%s: bad request, must be multiple of %d\n",
1102 			    st->sc_dev.dv_xname, st->blksize);
1103 			bp->b_error = EIO;
1104 			goto bad;
1105 		}
1106 	}
1107 	/*
1108 	 * as are out-of-range requests on variable drives.
1109 	 */
1110 	else if (bp->b_bcount < st->blkmin ||
1111 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1112 		printf("%s: bad request, must be between %d and %d\n",
1113 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1114 		bp->b_error = EIO;
1115 		goto bad;
1116 	}
1117 	s = splbio();
1118 
1119 	/*
1120 	 * Place it in the queue of activities for this tape
1121 	 * at the end (a bit silly because we only have on user..
1122 	 * (but it could fork()))
1123 	 */
1124 	BUFQ_PUT(&st->buf_queue, bp);
1125 
1126 	/*
1127 	 * Tell the device to get going on the transfer if it's
1128 	 * not doing anything, otherwise just wait for completion
1129 	 * (All a bit silly if we're only allowing 1 open but..)
1130 	 */
1131 	ststart(st->sc_periph);
1132 
1133 	splx(s);
1134 	return;
1135 bad:
1136 	bp->b_flags |= B_ERROR;
1137 done:
1138 	/*
1139 	 * Correctly set the buf to indicate a completed xfer
1140 	 */
1141 	bp->b_resid = bp->b_bcount;
1142 	biodone(bp);
1143 	return;
1144 }
1145 
1146 /*
1147  * ststart looks to see if there is a buf waiting for the device
1148  * and that the device is not already busy. If both are true,
1149  * It dequeues the buf and creates a scsi command to perform the
1150  * transfer required. The transfer request will call scsipi_done
1151  * on completion, which will in turn call this routine again
1152  * so that the next queued transfer is performed.
1153  * The bufs are queued by the strategy routine (ststrategy)
1154  *
1155  * This routine is also called after other non-queued requests
1156  * have been made of the scsi driver, to ensure that the queue
1157  * continues to be drained.
1158  * ststart() is called at splbio
1159  */
1160 static void
1161 ststart(struct scsipi_periph *periph)
1162 {
1163 	struct st_softc *st = (void *)periph->periph_dev;
1164 	struct buf *bp;
1165 	struct scsi_rw_tape cmd;
1166 	struct scsipi_xfer *xs;
1167 	int flags, error;
1168 
1169 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1170 	/*
1171 	 * See if there is a buf to do and we are not already
1172 	 * doing one
1173 	 */
1174 	while (periph->periph_active < periph->periph_openings) {
1175 		/* if a special awaits, let it proceed first */
1176 		if (periph->periph_flags & PERIPH_WAITING) {
1177 			periph->periph_flags &= ~PERIPH_WAITING;
1178 			wakeup((caddr_t)periph);
1179 			return;
1180 		}
1181 
1182 		/*
1183 		 * If the device has been unmounted by the user
1184 		 * then throw away all requests until done.
1185 		 */
1186 		if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
1187 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
1188 			if ((bp = BUFQ_GET(&st->buf_queue)) != NULL) {
1189 				/* make sure that one implies the other.. */
1190 				periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1191 				bp->b_flags |= B_ERROR;
1192 				bp->b_error = EIO;
1193 				bp->b_resid = bp->b_bcount;
1194 				biodone(bp);
1195 				continue;
1196 			} else {
1197 				return;
1198 			}
1199 		}
1200 
1201 		if ((bp = BUFQ_PEEK(&st->buf_queue)) == NULL)
1202 			return;
1203 
1204 		/*
1205 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1206 		 */
1207 		if (st->flags & ST_FIXEDBLOCKS) {
1208 			/*
1209 			 * If we are at a filemark but have not reported it yet
1210 			 * then we should report it now
1211 			 */
1212 			if (st->flags & ST_AT_FILEMARK) {
1213 				if ((bp->b_flags & B_READ) == B_WRITE) {
1214 					/*
1215 					 * Handling of ST_AT_FILEMARK in
1216 					 * st_space will fill in the right file
1217 					 * mark count.
1218 					 * Back up over filemark
1219 					 */
1220 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1221 						BUFQ_GET(&st->buf_queue);
1222 						bp->b_flags |= B_ERROR;
1223 						bp->b_error = EIO;
1224 						biodone(bp);
1225 						continue;
1226 					}
1227 				} else {
1228 					BUFQ_GET(&st->buf_queue);
1229 					bp->b_resid = bp->b_bcount;
1230 					bp->b_error = 0;
1231 					bp->b_flags &= ~B_ERROR;
1232 					st->flags &= ~ST_AT_FILEMARK;
1233 					biodone(bp);
1234 					continue;	/* seek more work */
1235 				}
1236 			}
1237 		}
1238 		/*
1239 		 * If we are at EOM but have not reported it
1240 		 * yet then we should report it now.
1241 		 */
1242 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1243 			BUFQ_GET(&st->buf_queue);
1244 			bp->b_resid = bp->b_bcount;
1245 			if (st->flags & ST_EIO_PENDING) {
1246 				bp->b_error = EIO;
1247 				bp->b_flags |= B_ERROR;
1248 			}
1249 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1250 			biodone(bp);
1251 			continue;	/* seek more work */
1252 		}
1253 
1254 		/*
1255 		 * Fill out the scsi command
1256 		 */
1257 		memset(&cmd, 0, sizeof(cmd));
1258 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1259 		if ((bp->b_flags & B_READ) == B_WRITE) {
1260 			cmd.opcode = WRITE;
1261 			st->flags &= ~ST_FM_WRITTEN;
1262 			flags |= XS_CTL_DATA_OUT;
1263 		} else {
1264 			cmd.opcode = READ;
1265 			flags |= XS_CTL_DATA_IN;
1266 		}
1267 
1268 		/*
1269 		 * Handle "fixed-block-mode" tape drives by using the
1270 		 * block count instead of the length.
1271 		 */
1272 		if (st->flags & ST_FIXEDBLOCKS) {
1273 			cmd.byte2 |= SRW_FIXED;
1274 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1275 		} else
1276 			_lto3b(bp->b_bcount, cmd.len);
1277 
1278 		/*
1279 		 * Clear 'position updated' indicator
1280 		 */
1281 		st->flags &= ~ST_POSUPDATED;
1282 
1283 		/*
1284 		 * go ask the adapter to do all this for us
1285 		 */
1286 		xs = scsipi_make_xs(periph,
1287 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1288 		    (u_char *)bp->b_data, bp->b_bcount,
1289 		    0, ST_IO_TIME, bp, flags);
1290 		if (__predict_false(xs == NULL)) {
1291 			/*
1292 			 * out of memory. Keep this buffer in the queue, and
1293 			 * retry later.
1294 			 */
1295 			callout_reset(&st->sc_callout, hz / 2, strestart,
1296 			    periph);
1297 			return;
1298 		}
1299 		/*
1300 		 * need to dequeue the buffer before queuing the command,
1301 		 * because cdstart may be called recursively from the
1302 		 * HBA driver
1303 		 */
1304 #ifdef DIAGNOSTIC
1305 		if (BUFQ_GET(&st->buf_queue) != bp)
1306 			panic("ststart(): dequeued wrong buf");
1307 #else
1308 		BUFQ_GET(&st->buf_queue);
1309 #endif
1310 		error = scsipi_command(periph, xs,
1311 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1312 		    (u_char *)bp->b_data, bp->b_bcount,
1313 		    0, ST_IO_TIME, bp, flags);
1314 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
1315 		KASSERT(error == 0);
1316 	} /* go back and see if we can cram more work in.. */
1317 }
1318 
1319 static void
1320 strestart(void *v)
1321 {
1322 	int s = splbio();
1323 	ststart((struct scsipi_periph *)v);
1324 	splx(s);
1325 }
1326 
1327 
1328 static void
1329 stdone(struct scsipi_xfer *xs)
1330 {
1331 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1332 
1333 	if (xs->bp != NULL) {
1334 		if ((xs->bp->b_flags & B_READ) == B_WRITE) {
1335 			st->flags |= ST_WRITTEN;
1336 		} else {
1337 			st->flags &= ~ST_WRITTEN;
1338 		}
1339 #if NRND > 0
1340 		rnd_add_uint32(&st->rnd_source, xs->bp->b_blkno);
1341 #endif
1342 
1343 		if ((st->flags & ST_POSUPDATED) == 0) {
1344 			if (xs->bp->b_flags & B_ERROR) {
1345 				st->fileno = st->blkno = -1;
1346 			} else if (st->blkno != -1) {
1347 				if (st->flags & ST_FIXEDBLOCKS) {
1348 					st->blkno +=
1349 					    (xs->bp->b_bcount / st->blksize);
1350 				} else {
1351 					st->blkno++;
1352 				}
1353 			}
1354 		}
1355 	}
1356 }
1357 
1358 static int
1359 stread(dev_t dev, struct uio *uio, int iomode)
1360 {
1361 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1362 
1363 	return (physio(ststrategy, NULL, dev, B_READ,
1364 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1365 }
1366 
1367 static int
1368 stwrite(dev_t dev, struct uio *uio, int iomode)
1369 {
1370 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1371 
1372 	return (physio(ststrategy, NULL, dev, B_WRITE,
1373 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1374 }
1375 
1376 /*
1377  * Perform special action on behalf of the user;
1378  * knows about the internals of this device
1379  */
1380 static int
1381 stioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct proc *p)
1382 {
1383 	int error = 0;
1384 	int unit;
1385 	int number, nmarks, dsty;
1386 	int flags;
1387 	struct st_softc *st;
1388 	int hold_blksize;
1389 	u_int8_t hold_density;
1390 	struct mtop *mt = (struct mtop *) arg;
1391 
1392 	/*
1393 	 * Find the device that the user is talking about
1394 	 */
1395 	flags = 0;		/* give error messages, act on errors etc. */
1396 	unit = STUNIT(dev);
1397 	dsty = STDSTY(dev);
1398 	st = st_cd.cd_devs[unit];
1399 	hold_blksize = st->blksize;
1400 	hold_density = st->density;
1401 
1402 	switch ((u_int) cmd) {
1403 
1404 	case MTIOCGET: {
1405 		struct mtget *g = (struct mtget *) arg;
1406 		/*
1407 		 * (to get the current state of READONLY)
1408 		 */
1409 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1410 		if (error) {
1411 			/*
1412 			 * Ignore the error if in control mode;
1413 			 * this is mandated by st(4).
1414 			 */
1415 			if (STMODE(dev) != CTRL_MODE)
1416 				break;
1417 			error = 0;
1418 		}
1419 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1420 		memset(g, 0, sizeof(struct mtget));
1421 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1422 		g->mt_blksiz = st->blksize;
1423 		g->mt_density = st->density;
1424 		g->mt_mblksiz[0] = st->modes[0].blksize;
1425 		g->mt_mblksiz[1] = st->modes[1].blksize;
1426 		g->mt_mblksiz[2] = st->modes[2].blksize;
1427 		g->mt_mblksiz[3] = st->modes[3].blksize;
1428 		g->mt_mdensity[0] = st->modes[0].density;
1429 		g->mt_mdensity[1] = st->modes[1].density;
1430 		g->mt_mdensity[2] = st->modes[2].density;
1431 		g->mt_mdensity[3] = st->modes[3].density;
1432 		g->mt_fileno = st->fileno;
1433 		g->mt_blkno = st->blkno;
1434 		if (st->flags & ST_READONLY)
1435 			g->mt_dsreg |= MT_DS_RDONLY;
1436 		if (st->flags & ST_MOUNTED)
1437 			g->mt_dsreg |= MT_DS_MOUNTED;
1438 		g->mt_resid = st->mt_resid;
1439 		g->mt_erreg = st->mt_erreg;
1440 		/*
1441 		 * clear latched errors.
1442 		 */
1443 		st->mt_resid = 0;
1444 		st->mt_erreg = 0;
1445 		st->asc = 0;
1446 		st->ascq = 0;
1447 		break;
1448 	}
1449 	case MTIOCTOP: {
1450 
1451 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1452 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1453 			mt->mt_count));
1454 
1455 		/* compat: in U*x it is a short */
1456 		number = mt->mt_count;
1457 		switch ((short) (mt->mt_op)) {
1458 		case MTWEOF:	/* write an end-of-file record */
1459 			error = st_write_filemarks(st, number, flags);
1460 			break;
1461 		case MTBSF:	/* backward space file */
1462 			number = -number;
1463 		case MTFSF:	/* forward space file */
1464 			error = st_check_eod(st, FALSE, &nmarks, flags);
1465 			if (!error)
1466 				error = st_space(st, number - nmarks,
1467 				    SP_FILEMARKS, flags);
1468 			break;
1469 		case MTBSR:	/* backward space record */
1470 			number = -number;
1471 		case MTFSR:	/* forward space record */
1472 			error = st_check_eod(st, TRUE, &nmarks, flags);
1473 			if (!error)
1474 				error = st_space(st, number, SP_BLKS, flags);
1475 			break;
1476 		case MTREW:	/* rewind */
1477 			error = st_rewind(st, 0, flags);
1478 			break;
1479 		case MTOFFL:	/* rewind and put the drive offline */
1480 			st_unmount(st, EJECT);
1481 			break;
1482 		case MTNOP:	/* no operation, sets status only */
1483 			break;
1484 		case MTRETEN:	/* retension the tape */
1485 			error = st_load(st, LD_RETENSION, flags);
1486 			if (!error)
1487 				error = st_load(st, LD_LOAD, flags);
1488 			break;
1489 		case MTEOM:	/* forward space to end of media */
1490 			error = st_check_eod(st, FALSE, &nmarks, flags);
1491 			if (!error)
1492 				error = st_space(st, 1, SP_EOM, flags);
1493 			break;
1494 		case MTCACHE:	/* enable controller cache */
1495 			st->flags &= ~ST_DONTBUFFER;
1496 			goto try_new_value;
1497 		case MTNOCACHE:	/* disable controller cache */
1498 			st->flags |= ST_DONTBUFFER;
1499 			goto try_new_value;
1500 		case MTERASE:	/* erase volume */
1501 			error = st_erase(st, number, flags);
1502 			break;
1503 		case MTSETBSIZ:	/* Set block size for device */
1504 #ifdef	NOTYET
1505 			if (!(st->flags & ST_NEW_MOUNT)) {
1506 				uprintf("re-mount tape before changing blocksize");
1507 				error = EINVAL;
1508 				break;
1509 			}
1510 #endif
1511 			if (number == 0)
1512 				st->flags &= ~ST_FIXEDBLOCKS;
1513 			else {
1514 				if ((st->blkmin || st->blkmax) &&
1515 				    (number < st->blkmin ||
1516 				    number > st->blkmax)) {
1517 					error = EINVAL;
1518 					break;
1519 				}
1520 				st->flags |= ST_FIXEDBLOCKS;
1521 			}
1522 			st->blksize = number;
1523 			st->flags |= ST_BLOCK_SET;	/*XXX */
1524 			goto try_new_value;
1525 
1526 		case MTSETDNSTY:	/* Set density for device and mode */
1527 			/*
1528 			 * Any number >= 0 and <= 0xff is legal. Numbers
1529 			 * above 0x80 are 'vendor unique'.
1530 			 */
1531 			if (number < 0 || number > 255) {
1532 				error = EINVAL;
1533 				break;
1534 			} else
1535 				st->density = number;
1536 			goto try_new_value;
1537 
1538 		case MTCMPRESS:
1539 			error = st->ops(st, (number == 0) ?
1540 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1541 			    XS_CTL_SILENT);
1542 			break;
1543 
1544 		case MTEWARN:
1545 			if (number)
1546 				st->flags |= ST_EARLYWARN;
1547 			else
1548 				st->flags &= ~ST_EARLYWARN;
1549 			break;
1550 
1551 		default:
1552 			error = EINVAL;
1553 		}
1554 		break;
1555 	}
1556 	case MTIOCIEOT:
1557 	case MTIOCEEOT:
1558 		break;
1559 
1560 	case MTIOCRDSPOS:
1561 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1562 		break;
1563 
1564 	case MTIOCRDHPOS:
1565 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1566 		break;
1567 
1568 	case MTIOCSLOCATE:
1569 		error = st_setpos(st, 0, (u_int32_t *) arg);
1570 		break;
1571 
1572 	case MTIOCHLOCATE:
1573 		error = st_setpos(st, 1, (u_int32_t *) arg);
1574 		break;
1575 
1576 
1577 	default:
1578 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1579 					flag, p);
1580 		break;
1581 	}
1582 	return (error);
1583 /*-----------------------------*/
1584 try_new_value:
1585 	/*
1586 	 * Check that the mode being asked for is aggreeable to the
1587 	 * drive. If not, put it back the way it was.
1588 	 *
1589 	 * If in control mode, we can make (persistent) mode changes
1590 	 * even if no medium is loaded (see st(4)).
1591 	 */
1592 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1593 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1594 		/* put it back as it was */
1595 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1596 		st->density = hold_density;
1597 		st->blksize = hold_blksize;
1598 		if (st->blksize)
1599 			st->flags |= ST_FIXEDBLOCKS;
1600 		else
1601 			st->flags &= ~ST_FIXEDBLOCKS;
1602 		return (error);
1603 	}
1604 	/*
1605 	 * As the drive liked it, if we are setting a new default,
1606 	 * set it into the structures as such.
1607 	 *
1608 	 * The means for deciding this are not finalised yet- but
1609 	 * if the device was opened in Control Mode, the values
1610 	 * are persistent now across mounts.
1611 	 */
1612 	if (STMODE(dev) == CTRL_MODE) {
1613 		switch ((short) (mt->mt_op)) {
1614 		case MTSETBSIZ:
1615 			st->modes[dsty].blksize = st->blksize;
1616 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1617 			break;
1618 		case MTSETDNSTY:
1619 			st->modes[dsty].density = st->density;
1620 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1621 			break;
1622 		}
1623 	}
1624 	return (0);
1625 }
1626 
1627 /*
1628  * Do a synchronous read.
1629  */
1630 static int
1631 st_read(struct st_softc *st, char *buf, int size, int flags)
1632 {
1633 	struct scsi_rw_tape cmd;
1634 
1635 	/*
1636 	 * If it's a null transfer, return immediatly
1637 	 */
1638 	if (size == 0)
1639 		return (0);
1640 	memset(&cmd, 0, sizeof(cmd));
1641 	cmd.opcode = READ;
1642 	if (st->flags & ST_FIXEDBLOCKS) {
1643 		cmd.byte2 |= SRW_FIXED;
1644 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1645 		    cmd.len);
1646 	} else
1647 		_lto3b(size, cmd.len);
1648 	return (scsipi_command(st->sc_periph, NULL,
1649 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1650 	    (u_char *)buf, size, 0, ST_IO_TIME, NULL, flags | XS_CTL_DATA_IN));
1651 }
1652 
1653 /*
1654  * issue an erase command
1655  */
1656 static int
1657 st_erase(struct st_softc *st, int full, int flags)
1658 {
1659 	int tmo;
1660 	struct scsi_erase cmd;
1661 
1662 	/*
1663 	 * Full erase means set LONG bit in erase command, which asks
1664 	 * the drive to erase the entire unit.  Without this bit, we're
1665 	 * asking the drive to write an erase gap.
1666 	 */
1667 	memset(&cmd, 0, sizeof(cmd));
1668 	cmd.opcode = ERASE;
1669 	if (full) {
1670 		cmd.byte2 = SE_LONG;
1671 		tmo = ST_SPC_TIME;
1672 	} else {
1673 		tmo = ST_IO_TIME;
1674 	}
1675 
1676 	/*
1677 	 * XXX We always do this asynchronously, for now, unless the device
1678 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1679 	 * want to (eventually) to it synchronously?
1680 	 */
1681 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1682 		cmd.byte2 |= SE_IMMED;
1683 
1684 	return (scsipi_command(st->sc_periph, NULL,
1685 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1686 	    0, 0, ST_RETRIES, tmo, NULL, flags));
1687 }
1688 
1689 /*
1690  * skip N blocks/filemarks/seq filemarks/eom
1691  */
1692 static int
1693 st_space(struct st_softc *st, int number, u_int what, int flags)
1694 {
1695 	struct scsi_space cmd;
1696 	int error;
1697 
1698 	switch (what) {
1699 	case SP_BLKS:
1700 		if (st->flags & ST_PER_ACTION) {
1701 			if (number > 0) {
1702 				st->flags &= ~ST_PER_ACTION;
1703 				return (EIO);
1704 			} else if (number < 0) {
1705 				if (st->flags & ST_AT_FILEMARK) {
1706 					/*
1707 					 * Handling of ST_AT_FILEMARK
1708 					 * in st_space will fill in the
1709 					 * right file mark count.
1710 					 */
1711 					error = st_space(st, 0, SP_FILEMARKS,
1712 					    flags);
1713 					if (error)
1714 						return (error);
1715 				}
1716 				if (st->flags & ST_BLANK_READ) {
1717 					st->flags &= ~ST_BLANK_READ;
1718 					return (EIO);
1719 				}
1720 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1721 			}
1722 		}
1723 		break;
1724 	case SP_FILEMARKS:
1725 		if (st->flags & ST_EIO_PENDING) {
1726 			if (number > 0) {
1727 				/* pretend we just discovered the error */
1728 				st->flags &= ~ST_EIO_PENDING;
1729 				return (EIO);
1730 			} else if (number < 0) {
1731 				/* back away from the error */
1732 				st->flags &= ~ST_EIO_PENDING;
1733 			}
1734 		}
1735 		if (st->flags & ST_AT_FILEMARK) {
1736 			st->flags &= ~ST_AT_FILEMARK;
1737 			number--;
1738 		}
1739 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1740 			/* back away from unwritten tape */
1741 			st->flags &= ~ST_BLANK_READ;
1742 			number++;	/* XXX dubious */
1743 		}
1744 		break;
1745 	case SP_EOM:
1746 		if (st->flags & ST_EOM_PENDING) {
1747 			/* we're already there */
1748 			st->flags &= ~ST_EOM_PENDING;
1749 			return (0);
1750 		}
1751 		if (st->flags & ST_EIO_PENDING) {
1752 			/* pretend we just discovered the error */
1753 			st->flags &= ~ST_EIO_PENDING;
1754 			return (EIO);
1755 		}
1756 		if (st->flags & ST_AT_FILEMARK)
1757 			st->flags &= ~ST_AT_FILEMARK;
1758 		break;
1759 	}
1760 	if (number == 0)
1761 		return (0);
1762 
1763 	memset(&cmd, 0, sizeof(cmd));
1764 	cmd.opcode = SPACE;
1765 	cmd.byte2 = what;
1766 	_lto3b(number, cmd.number);
1767 
1768 	st->flags &= ~ST_POSUPDATED;
1769 	st->last_ctl_resid = 0;
1770 	error = scsipi_command(st->sc_periph, NULL,
1771 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1772 	    0, 0, 0, ST_SPC_TIME, NULL, flags);
1773 
1774 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1775 		number = number - st->last_ctl_resid;
1776 		if (what == SP_BLKS) {
1777 			if (st->blkno != -1) {
1778 				st->blkno += number;
1779 			}
1780 		} else if (what == SP_FILEMARKS) {
1781 			if (st->fileno != -1) {
1782 				st->fileno += number;
1783 				if (number > 0) {
1784 					st->blkno = 0;
1785 				} else if (number < 0) {
1786 					st->blkno = -1;
1787 				}
1788 			}
1789 		} else if (what == SP_EOM) {
1790 			/*
1791 			 * This loses us relative position.
1792 			 */
1793 			st->fileno = st->blkno = -1;
1794 		}
1795 	}
1796 	return (error);
1797 }
1798 
1799 /*
1800  * write N filemarks
1801  */
1802 static int
1803 st_write_filemarks(struct st_softc *st, int number, int flags)
1804 {
1805 	int error;
1806 	struct scsi_write_filemarks cmd;
1807 
1808 	/*
1809 	 * It's hard to write a negative number of file marks.
1810 	 * Don't try.
1811 	 */
1812 	if (number < 0)
1813 		return (EINVAL);
1814 	switch (number) {
1815 	case 0:		/* really a command to sync the drive's buffers */
1816 		break;
1817 	case 1:
1818 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1819 			st->flags &= ~ST_WRITTEN;
1820 		else
1821 			st->flags |= ST_FM_WRITTEN;
1822 		st->flags &= ~ST_PER_ACTION;
1823 		break;
1824 	default:
1825 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1826 	}
1827 
1828 	memset(&cmd, 0, sizeof(cmd));
1829 	cmd.opcode = WRITE_FILEMARKS;
1830 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1831 		cmd.byte2 = SR_IMMED;
1832 	/*
1833 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1834 	 * WRITE_FILEMARKS is still used to flush the buffer
1835 	 */
1836 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1837 		_lto3b(number, cmd.number);
1838 
1839 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1840 	error = scsipi_command(st->sc_periph, NULL,
1841 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1842 	    0, 0, 0, ST_IO_TIME * 4, NULL, flags);
1843 	if (error == 0 && st->fileno != -1) {
1844 		st->fileno += number;
1845 	}
1846 	return (error);
1847 }
1848 
1849 /*
1850  * Make sure the right number of file marks is on tape if the
1851  * tape has been written.  If the position argument is true,
1852  * leave the tape positioned where it was originally.
1853  *
1854  * nmarks returns the number of marks to skip (or, if position
1855  * true, which were skipped) to get back original position.
1856  */
1857 static int
1858 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
1859 {
1860 	int error;
1861 
1862 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1863 	default:
1864 		*nmarks = 0;
1865 		return (0);
1866 	case ST_WRITTEN:
1867 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1868 		*nmarks = 1;
1869 		break;
1870 	case ST_WRITTEN | ST_2FM_AT_EOD:
1871 		*nmarks = 2;
1872 	}
1873 	error = st_write_filemarks(st, *nmarks, flags);
1874 	if (position && !error)
1875 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1876 	return (error);
1877 }
1878 
1879 /*
1880  * load/unload/retension
1881  */
1882 static int
1883 st_load(struct st_softc *st, u_int type, int flags)
1884 {
1885 	int error;
1886 	struct scsi_load cmd;
1887 
1888 	if (type != LD_LOAD) {
1889 		int nmarks;
1890 
1891 		error = st_check_eod(st, FALSE, &nmarks, flags);
1892 		if (error) {
1893 			printf("%s: failed to write closing filemarks at "
1894 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1895 			return (error);
1896 		}
1897 	}
1898 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1899 		if (type == LD_LOAD) {
1900 			/*
1901 			 * If we ignore loads, at least we should try a rewind.
1902 			 */
1903 			return st_rewind(st, 0, flags);
1904 		}
1905 		/* otherwise, we should do what's asked of us */
1906 	}
1907 
1908 	memset(&cmd, 0, sizeof(cmd));
1909 	cmd.opcode = LOAD;
1910 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1911 		cmd.byte2 = SR_IMMED;
1912 	cmd.how = type;
1913 
1914 	error = scsipi_command(st->sc_periph, NULL,
1915 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
1916 	    0, 0, ST_RETRIES, ST_SPC_TIME, NULL, flags);
1917 	if (error) {
1918 		printf("%s: error %d in st_load (op %d)\n",
1919 		    st->sc_dev.dv_xname, error, type);
1920 	}
1921 	return (error);
1922 }
1923 
1924 /*
1925  *  Rewind the device
1926  */
1927 static int
1928 st_rewind(struct st_softc *st, u_int immediate, int flags)
1929 {
1930 	struct scsi_rewind cmd;
1931 	int error;
1932 	int nmarks;
1933 
1934 	error = st_check_eod(st, FALSE, &nmarks, flags);
1935 	if (error) {
1936 		printf("%s: failed to write closing filemarks at "
1937 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1938 		return (error);
1939 	}
1940 	st->flags &= ~ST_PER_ACTION;
1941 
1942 	/*
1943 	 * ATAPI tapes always need immediate to be set
1944 	 */
1945 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1946 		immediate = SR_IMMED;
1947 
1948 	memset(&cmd, 0, sizeof(cmd));
1949 	cmd.opcode = REWIND;
1950 	cmd.byte2 = immediate;
1951 
1952 	error = scsipi_command(st->sc_periph, NULL,
1953 	    (struct scsipi_generic *)&cmd, sizeof(cmd), 0, 0, ST_RETRIES,
1954 	    immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
1955 	if (error) {
1956 		printf("%s: error %d trying to rewind\n",
1957 		    st->sc_dev.dv_xname, error);
1958 		/* lost position */
1959 		st->fileno = st->blkno = -1;
1960 	} else {
1961 		st->fileno = st->blkno = 0;
1962 	}
1963 	return (error);
1964 }
1965 
1966 static int
1967 st_rdpos(struct st_softc *st, int hard, u_int32_t *blkptr)
1968 {
1969 	int error;
1970 	u_int8_t posdata[20];
1971 	struct scsi_tape_read_position cmd;
1972 
1973 	/*
1974 	 * We try and flush any buffered writes here if we were writing
1975 	 * and we're trying to get hardware block position. It eats
1976 	 * up performance substantially, but I'm wary of drive firmware.
1977 	 *
1978 	 * I think that *logical* block position is probably okay-
1979 	 * but hardware block position might have to wait for data
1980 	 * to hit media to be valid. Caveat Emptor.
1981 	 */
1982 
1983 	if (hard && (st->flags & ST_WRITTEN)) {
1984 		/*
1985 		 * First flush any pending writes...
1986 		 */
1987 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
1988 		/*
1989 		 * The latter case is for 'write protected' tapes
1990 		 * which are too stupid to recognize a zero count
1991 		 * for writing filemarks as a no-op.
1992 		 */
1993 		if (error != 0 && error != EACCES && error != EROFS)
1994 			return (error);
1995 	}
1996 
1997 	memset(&cmd, 0, sizeof(cmd));
1998 	memset(&posdata, 0, sizeof(posdata));
1999 	cmd.opcode = READ_POSITION;
2000 	if (hard)
2001 		cmd.byte1 = 1;
2002 
2003 	error = scsipi_command(st->sc_periph, NULL,
2004 	    (struct scsipi_generic *)&cmd, sizeof(cmd), (u_char *)&posdata,
2005 	    sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
2006 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
2007 
2008 	if (error == 0) {
2009 #if	0
2010 		printf("posdata:");
2011 		for (hard = 0; hard < sizeof(posdata); hard++)
2012 			printf("%02x ", posdata[hard] & 0xff);
2013 		printf("\n");
2014 #endif
2015 		if (posdata[0] & 0x4)	/* Block Position Unknown */
2016 			error = EINVAL;
2017 		else
2018 			*blkptr = _4btol(&posdata[4]);
2019 	}
2020 	return (error);
2021 }
2022 
2023 static int
2024 st_setpos(struct st_softc *st, int hard, u_int32_t *blkptr)
2025 {
2026 	int error;
2027 	struct scsi_tape_locate cmd;
2028 
2029 	/*
2030 	 * We used to try and flush any buffered writes here.
2031 	 * Now we push this onto user applications to either
2032 	 * flush the pending writes themselves (via a zero count
2033 	 * WRITE FILEMARKS command) or they can trust their tape
2034 	 * drive to do this correctly for them.
2035 	 *
2036 	 * There are very ugly performance limitations otherwise.
2037 	 */
2038 
2039 	memset(&cmd, 0, sizeof(cmd));
2040 	cmd.opcode = LOCATE;
2041 	if (hard)
2042 		cmd.byte2 = 1 << 2;
2043 	_lto4b(*blkptr, cmd.blkaddr);
2044 	error = scsipi_command(st->sc_periph, NULL,
2045 		(struct scsipi_generic *)&cmd, sizeof(cmd),
2046 		NULL, 0, ST_RETRIES, ST_SPC_TIME, NULL, 0);
2047 	/*
2048 	 * Note file && block number position now unknown (if
2049 	 * these things ever start being maintained in this driver)
2050 	 */
2051 	st->fileno = st->blkno = -1;
2052 	return (error);
2053 }
2054 
2055 
2056 /*
2057  * Look at the returned sense and act on the error and determine
2058  * the unix error number to pass back..., 0 (== report no error),
2059  * -1 = retry the operation, -2 continue error processing.
2060  */
2061 static int
2062 st_interpret_sense(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_pending(&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 static int
2340 st_touch_tape(struct st_softc *st)
2341 {
2342 	char *buf;
2343 	int readsize;
2344 	int error;
2345 
2346 	buf = malloc(1024, M_TEMP, M_NOWAIT);
2347 	if (buf == NULL)
2348 		return (ENOMEM);
2349 
2350 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
2351 		goto bad;
2352 
2353 	/*
2354 	 * If the block size is already known from the
2355 	 * sense data, use it. Else start probing at 1024.
2356 	 */
2357 	if (st->media_blksize > 0)
2358 		st->blksize = st->media_blksize;
2359 	else
2360 		st->blksize = 1024;
2361 
2362 	do {
2363 		switch (st->blksize) {
2364 		case 512:
2365 		case 1024:
2366 			readsize = st->blksize;
2367 			st->flags |= ST_FIXEDBLOCKS;
2368 			break;
2369 		default:
2370 			readsize = 1;
2371 			st->flags &= ~ST_FIXEDBLOCKS;
2372 		}
2373 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
2374 		    != 0) {
2375 			/*
2376 			 * The device did not agree with the proposed
2377 			 * block size. If we exhausted our options,
2378 			 * return failure, else try another.
2379 			 */
2380 			if (readsize == 1)
2381 				goto bad;
2382 			st->blksize -= 512;
2383 			continue;
2384 		}
2385 		st_read(st, buf, readsize, XS_CTL_SILENT);	/* XXX */
2386 		if ((error = st_rewind(st, 0, 0)) != 0) {
2387 bad:			free(buf, M_TEMP);
2388 			return (error);
2389 		}
2390 	} while (readsize != 1 && readsize > st->blksize);
2391 
2392 	free(buf, M_TEMP);
2393 	return (0);
2394 }
2395 
2396 static int
2397 stdump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
2398 {
2399 
2400 	/* Not implemented. */
2401 	return (ENXIO);
2402 }
2403