xref: /netbsd-src/sys/dev/scsipi/st.c (revision aa73cae19608873cc4d1f712c4a0f8f8435f1ffa)
1 /*	$NetBSD: st.c,v 1.178 2005/02/27 00:27:48 perry Exp $ */
2 
3 /*-
4  * Copyright (c) 1998, 2004 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 1.178 2005/02/27 00:27:48 perry 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/bufq.h>
72 #include <sys/proc.h>
73 #include <sys/user.h>
74 #include <sys/mtio.h>
75 #include <sys/device.h>
76 #include <sys/conf.h>
77 #include <sys/kernel.h>
78 #include <sys/vnode.h>
79 
80 #include <dev/scsipi/scsi_spc.h>
81 #include <dev/scsipi/scsipi_all.h>
82 #include <dev/scsipi/scsi_all.h>
83 #include <dev/scsipi/scsi_tape.h>
84 #include <dev/scsipi/scsipiconf.h>
85 #include <dev/scsipi/scsipi_base.h>
86 #include <dev/scsipi/stvar.h>
87 
88 /* Defines for device specific stuff */
89 #define DEF_FIXED_BSIZE  512
90 
91 #define STMODE(z)	( minor(z)       & 0x03)
92 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
93 #define STUNIT(z)	((minor(z) >> 4)       )
94 #define STNMINOR	16
95 
96 #define NORMAL_MODE	0
97 #define NOREW_MODE	1
98 #define EJECT_MODE	2
99 #define CTRL_MODE	3
100 
101 #define	FALSE		0
102 #define	TRUE		1
103 
104 #ifndef		ST_MOUNT_DELAY
105 #define		ST_MOUNT_DELAY		0
106 #endif
107 
108 static dev_type_open(stopen);
109 static dev_type_close(stclose);
110 static dev_type_read(stread);
111 static dev_type_write(stwrite);
112 static dev_type_ioctl(stioctl);
113 static dev_type_strategy(ststrategy);
114 static dev_type_dump(stdump);
115 
116 const struct bdevsw st_bdevsw = {
117 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
118 };
119 
120 const struct cdevsw st_cdevsw = {
121 	stopen, stclose, stread, stwrite, stioctl,
122 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
123 };
124 
125 /*
126  * Define various devices that we know mis-behave in some way,
127  * and note how they are bad, so we can correct for them
128  */
129 
130 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
131 	{{T_SEQUENTIAL, T_REMOV,
132 	 "        ", "                ", "    "}, {0, 0, {
133 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
134 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
135 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
136 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
137 	}}},
138 	{{T_SEQUENTIAL, T_REMOV,
139 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
140 		{0, 0, 0},				/* minor 0-3 */
141 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
142 		{0, 0, QIC_150},			/* minor 8-11 */
143 		{0, 0, QIC_120}				/* minor 12-15 */
144 	}}},
145  	{{T_SEQUENTIAL, T_REMOV,
146  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
147 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
148 		{0, 0, QIC_525},			/* minor 4-7 */
149 		{0, 0, QIC_150},			/* minor 8-11 */
150 		{0, 0, QIC_120}				/* minor 12-15 */
151 	}}},
152 	{{T_SEQUENTIAL, T_REMOV,
153 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
154 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
155 		{0, 0, 0},				/* minor 4-7 */
156 		{0, 0, 0},				/* minor 8-11 */
157 		{0, 0, 0}				/* minor 12-15 */
158 	}}},
159 	/*
160 	 * lacking a manual for the 4200, it's not clear what the
161 	 * specific density codes should be- the device is a 2.5GB
162 	 * capable QIC drive, those density codes aren't readily
163 	 * availabel. The 'default' will just have to do.
164 	 */
165  	{{T_SEQUENTIAL, T_REMOV,
166  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
167 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
168 		{0, 0, QIC_525},			/* minor 4-7 */
169 		{0, 0, QIC_150},			/* minor 8-11 */
170 		{0, 0, QIC_120}				/* minor 12-15 */
171 	}}},
172 	/*
173 	 * At least -005 and -007 need this.  I'll assume they all do unless I
174 	 * hear otherwise.  - mycroft, 31MAR1994
175 	 */
176 	{{T_SEQUENTIAL, T_REMOV,
177 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
178 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
179 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
180 		{0, 0, QIC_150},			/* minor 8-11 */
181 		{0, 0, QIC_120}				/* minor 12-15 */
182 	}}},
183 	/*
184 	 * One user reports that this works for his tape drive.  It probably
185 	 * needs more work.  - mycroft, 09APR1994
186 	 */
187 	{{T_SEQUENTIAL, T_REMOV,
188 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
189 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
190 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
191 		{0, 0, QIC_150},			/* minor 8-11 */
192 		{0, 0, QIC_120}				/* minor 12-15 */
193 	}}},
194 	{{T_SEQUENTIAL, T_REMOV,
195 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
196 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
197 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
198 		{0, 0, QIC_150},			/* minor 8-11 */
199 		{0, 0, QIC_120}				/* minor 12-15 */
200 	}}},
201 	{{T_SEQUENTIAL, T_REMOV,
202 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
203 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
204 		{0, 0, QIC_150},			/* minor 4-7 */
205 		{0, 0, QIC_120},			/* minor 8-11 */
206 		{0, 0, QIC_24}				/* minor 12-15 */
207 	}}},
208 	{{T_SEQUENTIAL, T_REMOV,
209 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
210 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
211 		{0, 0, QIC_150},			/* minor 4-7 */
212 		{0, 0, QIC_120},			/* minor 8-11 */
213 		{0, 0, QIC_24}				/* minor 12-15 */
214 	}}},
215 	{{T_SEQUENTIAL, T_REMOV,
216 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
217 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
218 		{0, 0, QIC_11},				/* minor 4-7 */
219 		{0, 0, QIC_24},				/* minor 8-11 */
220 		{0, 0, QIC_24}				/* minor 12-15 */
221 	}}},
222 	{{T_SEQUENTIAL, T_REMOV,
223 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
224 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
225 		{0, 0, QIC_24},				/* minor 4-7 */
226 		{0, 0, QIC_120},			/* minor 8-11 */
227 		{0, 0, QIC_150}				/* minor 12-15 */
228 	}}},
229 	{{T_SEQUENTIAL, T_REMOV,
230 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
231 		{0, 0, 0},				/* minor 0-3 */
232 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
233 		{0, 0, QIC_150},			/* minor 8-11 */
234 		{0, 0, QIC_120}				/* minor 12-15 */
235 	}}},
236 	{{T_SEQUENTIAL, T_REMOV,
237 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
238 		{0, 0, 0},				/* minor 0-3 */
239 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
240 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
241 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
242 	}}},
243 	{{T_SEQUENTIAL, T_REMOV,
244 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
245 		{0, 0, 0},				/* minor 0-3 */
246 		{0, 0, 0},				/* minor 4-7 */
247 		{0, 0, 0},				/* minor 8-11 */
248 		{0, 0, 0}				/* minor 12-15 */
249 	}}},
250 	{{T_SEQUENTIAL, T_REMOV,
251 	 "STK",      "9490",             ""},
252 				{ST_Q_FORCE_BLKSIZE, 0, {
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 	{{T_SEQUENTIAL, T_REMOV,
259 	 "STK",      "SD-3",             ""},
260 				{ST_Q_FORCE_BLKSIZE, 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 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
268 		{0, 0, 0},				/* minor 0-3 */
269 		{0, 0, 0},				/* minor 4-7 */
270 		{0, 0, 0},				/* minor 8-11 */
271 		{0, 0, 0}				/* minor 12-15 */
272 	}}},
273 	{{T_SEQUENTIAL, T_REMOV,
274 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
275 		{0, 0, QIC_3095},			/* minor 0-3 */
276 		{0, 0, QIC_3095},			/* minor 4-7 */
277 		{0, 0, QIC_3095},			/* minor 8-11 */
278 		{0, 0, QIC_3095},			/* minor 12-15 */
279 	}}},
280 #if 0
281 	{{T_SEQUENTIAL, T_REMOV,
282 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
283 		{0, 0, 0},				/* minor 0-3 */
284 		{0, 0, 0},				/* minor 4-7 */
285 		{0, 0, 0},				/* minor 8-11 */
286 		{0, 0, 0}				/* minor 12-15 */
287 	}}},
288 #endif
289 	{{T_SEQUENTIAL, T_REMOV,
290 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
291 		{0, 0, 0},			        /* minor 0-3 */
292 		{0, 0, 0},			        /* minor 4-7 */
293 		{0, 0, 0},			        /* minor 8-11 */
294 		{0, 0, 0}			        /* minor 12-15 */
295 	}}},
296 	{{T_SEQUENTIAL, T_REMOV,
297 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
298 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
299 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
300 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
301 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
302 	}}},
303 	{{T_SEQUENTIAL, T_REMOV,
304 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
305 		{0, 0, 0},                              /* minor 0-3 */
306 		{0, 0, 0},                              /* minor 4-7 */
307 		{0, 0, 0},                              /* minor 8-11 */
308 		{0, 0, 0}                               /* minor 12-15 */
309 	}}},
310 	{{T_SEQUENTIAL, T_REMOV,
311 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
312 		{0, 0, 0},			       /* minor 0-3 */
313 		{0, 0, 0},			       /* minor 4-7 */
314 		{0, 0, 0},			       /* minor 8-11 */
315 		{0, 0, 0}			       /* minor 12-15 */
316 	}}},
317 };
318 
319 #define NOEJECT 0
320 #define EJECT 1
321 
322 static void	st_identify_drive(struct st_softc *,
323 		    struct scsipi_inquiry_pattern *);
324 static void	st_loadquirks(struct st_softc *);
325 static int	st_mount_tape(dev_t, int);
326 static void	st_unmount(struct st_softc *, boolean);
327 static int	st_decide_mode(struct st_softc *, boolean);
328 static void	ststart(struct scsipi_periph *);
329 static void	strestart(void *);
330 static void	stdone(struct scsipi_xfer *, int);
331 static int	st_read(struct st_softc *, char *, int, int);
332 static int	st_space(struct st_softc *, int, u_int, int);
333 static int	st_write_filemarks(struct st_softc *, int, int);
334 static int	st_check_eod(struct st_softc *, boolean, int *, int);
335 static int	st_load(struct st_softc *, u_int, int);
336 static int	st_rewind(struct st_softc *, u_int, int);
337 static int	st_interpret_sense(struct scsipi_xfer *);
338 static int	st_touch_tape(struct st_softc *);
339 static int	st_erase(struct st_softc *, int full, int flags);
340 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
341 static int	st_setpos(struct st_softc *, int, u_int32_t *);
342 
343 static const struct scsipi_periphsw st_switch = {
344 	st_interpret_sense,
345 	ststart,
346 	NULL,
347 	stdone
348 };
349 
350 #if	defined(ST_ENABLE_EARLYWARN)
351 #define	ST_INIT_FLAGS	ST_EARLYWARN
352 #else
353 #define	ST_INIT_FLAGS	0
354 #endif
355 
356 /*
357  * The routine called by the low level scsi routine when it discovers
358  * A device suitable for this driver
359  */
360 void
361 stattach(struct device *parent, struct st_softc *st, void *aux)
362 {
363 	struct scsipibus_attach_args *sa = aux;
364 	struct scsipi_periph *periph = sa->sa_periph;
365 
366 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
367 
368 	/*
369 	 * Store information needed to contact our base driver
370 	 */
371 	st->sc_periph = periph;
372 	periph->periph_dev = &st->sc_dev;
373 	periph->periph_switch = &st_switch;
374 
375 	/*
376 	 * Set initial flags
377 	 */
378 
379 	st->flags = ST_INIT_FLAGS;
380 
381 	/*
382 	 * Set up the buf queue for this device
383 	 */
384 	bufq_alloc(&st->buf_queue, BUFQ_FCFS);
385 
386 	callout_init(&st->sc_callout);
387 
388 	/*
389 	 * Check if the drive is a known criminal and take
390 	 * Any steps needed to bring it into line
391 	 */
392 	st_identify_drive(st, &sa->sa_inqbuf);
393 	/*
394 	 * Use the subdriver to request information regarding the drive.
395 	 */
396 	printf("\n");
397 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
398 	if (scsipi_test_unit_ready(periph,
399 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
400 	    st->ops(st, ST_OPS_MODESENSE,
401 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
402 		printf("drive empty\n");
403 	else {
404 		printf("density code %d, ", st->media_density);
405 		if (st->media_blksize > 0)
406 			printf("%d-byte", st->media_blksize);
407 		else
408 			printf("variable");
409 		printf(" blocks, write-%s\n",
410 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
411 	}
412 
413 #if NRND > 0
414 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
415 			  RND_TYPE_TAPE, 0);
416 #endif
417 }
418 
419 int
420 stactivate(struct device *self, enum devact act)
421 {
422 	int rv = 0;
423 
424 	switch (act) {
425 	case DVACT_ACTIVATE:
426 		rv = EOPNOTSUPP;
427 		break;
428 
429 	case DVACT_DEACTIVATE:
430 		/*
431 		 * Nothing to do; we key off the device's DVF_ACTIVE.
432 		 */
433 		break;
434 	}
435 	return (rv);
436 }
437 
438 int
439 stdetach(struct device *self, int flags)
440 {
441 	struct st_softc *st = (struct st_softc *)self;
442 	struct buf *bp;
443 	int s, bmaj, cmaj, mn;
444 
445 	/* locate the major number */
446 	bmaj = bdevsw_lookup_major(&st_bdevsw);
447 	cmaj = cdevsw_lookup_major(&st_cdevsw);
448 
449 	/* kill any pending restart */
450 	callout_stop(&st->sc_callout);
451 
452 	s = splbio();
453 
454 	/* Kill off any queued buffers. */
455 	while ((bp = BUFQ_GET(&st->buf_queue)) != NULL) {
456 		bp->b_error = EIO;
457 		bp->b_flags |= B_ERROR;
458 		bp->b_resid = bp->b_bcount;
459 		biodone(bp);
460 	}
461 
462 	bufq_free(&st->buf_queue);
463 
464 	/* Kill off any pending commands. */
465 	scsipi_kill_pending(st->sc_periph);
466 
467 	splx(s);
468 
469 	/* Nuke the vnodes for any open instances */
470 	mn = STUNIT(self->dv_unit);
471 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
472 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
473 
474 
475 #if NRND > 0
476 	/* Unhook the entropy source. */
477 	rnd_detach_source(&st->rnd_source);
478 #endif
479 
480 	return (0);
481 }
482 
483 /*
484  * Use the inquiry routine in 'scsi_base' to get drive info so we can
485  * Further tailor our behaviour.
486  */
487 static void
488 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
489 {
490 	struct st_quirk_inquiry_pattern *finger;
491 	int priority;
492 
493 	finger = (struct st_quirk_inquiry_pattern *)scsipi_inqmatch(inqbuf,
494 	    (caddr_t)st_quirk_patterns,
495 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
496 	    sizeof(st_quirk_patterns[0]), &priority);
497 	if (priority != 0) {
498 		st->quirkdata = &finger->quirkdata;
499 		st->drive_quirks = finger->quirkdata.quirks;
500 		st->quirks = finger->quirkdata.quirks;	/* start value */
501 		st->page_0_size = finger->quirkdata.page_0_size;
502 		st_loadquirks(st);
503 	}
504 }
505 
506 /*
507  * initialise the subdevices to the default (QUIRK) state.
508  * this will remove any setting made by the system operator or previous
509  * operations.
510  */
511 static void
512 st_loadquirks(struct st_softc *st)
513 {
514 	int i;
515 	struct	modes *mode;
516 	struct	modes *mode2;
517 
518 	mode = st->quirkdata->modes;
519 	mode2 = st->modes;
520 	for (i = 0; i < 4; i++) {
521 		memset(mode2, 0, sizeof(struct modes));
522 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
523 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
524 		    DENSITY_SET_BY_USER);
525 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
526 			mode2->blksize = mode->blksize;
527 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
528 		}
529 		if (mode->density) {
530 			mode2->density = mode->density;
531 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
532 		}
533 		mode2->quirks |= mode->quirks;
534 		mode++;
535 		mode2++;
536 	}
537 }
538 
539 /*
540  * open the device.
541  */
542 static int
543 stopen(dev_t dev, int flags, int mode, struct proc *p)
544 {
545 	u_int stmode, dsty;
546 	int error, sflags, unit, tries, ntries;
547 	struct st_softc *st;
548 	struct scsipi_periph *periph;
549 	struct scsipi_adapter *adapt;
550 
551 	unit = STUNIT(dev);
552 	if (unit >= st_cd.cd_ndevs)
553 		return (ENXIO);
554 	st = st_cd.cd_devs[unit];
555 	if (st == NULL)
556 		return (ENXIO);
557 
558 	stmode = STMODE(dev);
559 	dsty = STDSTY(dev);
560 
561 	periph = st->sc_periph;
562 	adapt = periph->periph_channel->chan_adapter;
563 
564 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
565 	    unit, st_cd.cd_ndevs));
566 
567 
568 	/*
569 	 * Only allow one at a time
570 	 */
571 	if (periph->periph_flags & PERIPH_OPEN) {
572 		printf("%s: already open\n", st->sc_dev.dv_xname);
573 		return (EBUSY);
574 	}
575 
576 	if ((error = scsipi_adapter_addref(adapt)) != 0)
577 		return (error);
578 
579 	/*
580 	 * clear any latched errors.
581 	 */
582 	st->mt_resid = 0;
583 	st->mt_erreg = 0;
584 	st->asc = 0;
585 	st->ascq = 0;
586 
587 	/*
588 	 * Catch any unit attention errors. Be silent about this
589 	 * unless we're already mounted. We ignore media change
590 	 * if we're in control mode or not mounted yet.
591 	 */
592 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
593 #ifdef SCSIDEBUG
594 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
595 #else
596 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
597 #endif
598 	} else
599 		sflags = 0;
600 
601 	/*
602 	 * If we're already mounted or we aren't configured for
603 	 * a mount delay, only try a test unit ready once. Otherwise,
604 	 * try up to ST_MOUNT_DELAY times with a rest interval of
605 	 * one second between each try.
606 	 */
607 
608 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
609 		ntries = 1;
610 	} else {
611 		ntries = ST_MOUNT_DELAY;
612 	}
613 
614 	for (error = tries = 0; tries < ntries; tries++) {
615 		int slpintr, oflags;
616 
617 		/*
618 		 * If we had no error, or we're opening the control mode
619 		 * device, we jump out right away.
620 		 */
621 
622 		error = scsipi_test_unit_ready(periph, sflags);
623 		if (error == 0 || stmode == CTRL_MODE) {
624 			break;
625 		}
626 
627 		/*
628 		 * We had an error.
629 		 *
630 		 * If we're already mounted or we aren't configured for
631 		 * a mount delay, or the error isn't a NOT READY error,
632 		 * skip to the error exit now.
633 		 */
634 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
635 		    (st->mt_key != SKEY_NOT_READY)) {
636 			goto bad;
637 		}
638 
639 		/*
640 		 * clear any latched errors.
641 		 */
642 		st->mt_resid = 0;
643 		st->mt_erreg = 0;
644 		st->asc = 0;
645 		st->ascq = 0;
646 
647 		/*
648 		 * Fake that we have the device open so
649 		 * we block other apps from getting in.
650 		 */
651 
652 		oflags = periph->periph_flags;
653 		periph->periph_flags |= PERIPH_OPEN;
654 
655 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
656 
657 		periph->periph_flags = oflags;	/* restore flags */
658 		if (slpintr) {
659 			goto bad;
660 		}
661 	}
662 
663 
664 	/*
665 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
666 	 * been opened to set defaults and perform other, usually non-I/O
667 	 * related, operations. In this case, do a quick check to see
668 	 * whether the unit actually had a tape loaded (this will be known
669 	 * as to whether or not we got a NOT READY for the above
670 	 * unit attention). If a tape is there, go do a mount sequence.
671 	 */
672 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
673 		periph->periph_flags |= PERIPH_OPEN;
674 		return (0);
675 	}
676 
677 	/*
678 	 * If we get this far and had an error set, that means we failed
679 	 * to pass the 'test unit ready' test for the non-controlmode device,
680 	 * so we bounce the open.
681 	 */
682 
683 	if (error)
684 		return (error);
685 
686 	/*
687 	 * Else, we're now committed to saying we're open.
688 	 */
689 
690 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
691 
692 	/*
693 	 * If it's a different mode, or if the media has been
694 	 * invalidated, unmount the tape from the previous
695 	 * session but continue with open processing
696 	 */
697 	if (st->last_dsty != dsty ||
698 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
699 		st_unmount(st, NOEJECT);
700 
701 	/*
702 	 * If we are not mounted, then we should start a new
703 	 * mount session.
704 	 */
705 	if (!(st->flags & ST_MOUNTED)) {
706 		if ((error = st_mount_tape(dev, flags)) != 0)
707 			goto bad;
708 		st->last_dsty = dsty;
709 	}
710 	if (!(st->quirks & ST_Q_NOPREVENT)) {
711 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
712 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
713 	}
714 
715 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
716 	return (0);
717 
718 bad:
719 	st_unmount(st, NOEJECT);
720 	scsipi_adapter_delref(adapt);
721 	periph->periph_flags &= ~PERIPH_OPEN;
722 	return (error);
723 }
724 
725 /*
726  * close the device.. only called if we are the LAST
727  * occurence of an open device
728  */
729 static int
730 stclose(dev_t dev, int flags, int mode, struct proc *p)
731 {
732 	int stxx, error = 0;
733 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
734 	struct scsipi_periph *periph = st->sc_periph;
735 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
736 
737 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
738 
739 	/*
740 	 * Make sure that a tape opened in write-only mode will have
741 	 * file marks written on it when closed, even if not written to.
742 	 *
743 	 * This is for SUN compatibility. Actually, the Sun way of
744 	 * things is to:
745 	 *
746 	 *	only write filemarks if there are fmks to be written and
747 	 *   		- open for write (possibly read/write)
748 	 *		- the last operation was a write
749 	 * 	or:
750 	 *		- opened for wronly
751 	 *		- no data was written (including filemarks)
752 	 */
753 
754 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
755 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
756 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
757 		int nm;
758 		error = st_check_eod(st, FALSE, &nm, 0);
759 	}
760 
761 	/*
762 	 * Allow robots to eject tape if needed.
763 	 */
764 	scsipi_prevent(periph, SPAMR_ALLOW,
765 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
766 
767 	switch (STMODE(dev)) {
768 	case NORMAL_MODE:
769 		st_unmount(st, NOEJECT);
770 		break;
771 	case NOREW_MODE:
772 	case CTRL_MODE:
773 		/*
774 		 * Leave mounted unless media seems to have been removed.
775 		 *
776 		 * Otherwise, if we're to terminate a tape with more than one
777 		 * filemark [ and because we're not rewinding here ], backspace
778 		 * one filemark so that later appends will see an unbroken
779 		 * sequence of:
780 		 *
781 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
782 		 */
783 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
784 			st_unmount(st, NOEJECT);
785 		} else if (error == 0) {
786 			/*
787 			 * ST_WRITTEN was preserved from above.
788 			 *
789 			 * All we need to know here is:
790 			 *
791 			 *	Were we writing this tape and was the last
792 			 *	operation a write?
793 			 *
794 			 *	Are there supposed to be 2FM at EOD?
795 			 *
796 			 * If both statements are true, then we backspace
797 			 * one filemark.
798 			 */
799 			stxx |= (st->flags & ST_2FM_AT_EOD);
800 			if ((flags & FWRITE) != 0 &&
801 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
802 				error = st_space(st, -1, SP_FILEMARKS, 0);
803 			}
804 		}
805 		break;
806 	case EJECT_MODE:
807 		st_unmount(st, EJECT);
808 		break;
809 	}
810 
811 	scsipi_wait_drain(periph);
812 
813 	scsipi_adapter_delref(adapt);
814 	periph->periph_flags &= ~PERIPH_OPEN;
815 
816 	return (error);
817 }
818 
819 /*
820  * Start a new mount session.
821  * Copy in all the default parameters from the selected device mode.
822  * and try guess any that seem to be defaulted.
823  */
824 static int
825 st_mount_tape(dev_t dev, int flags)
826 {
827 	int unit;
828 	u_int dsty;
829 	struct st_softc *st;
830 	struct scsipi_periph *periph;
831 	int error = 0;
832 
833 	unit = STUNIT(dev);
834 	dsty = STDSTY(dev);
835 	st = st_cd.cd_devs[unit];
836 	periph = st->sc_periph;
837 
838 	if (st->flags & ST_MOUNTED)
839 		return (0);
840 
841 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
842 	st->flags |= ST_NEW_MOUNT;
843 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
844 	/*
845 	 * If the media is new, then make sure we give it a chance to
846 	 * to do a 'load' instruction.  (We assume it is new.)
847 	 */
848 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
849 		return (error);
850 	/*
851 	 * Throw another dummy instruction to catch
852 	 * 'Unit attention' errors. Many drives give
853 	 * these after doing a Load instruction (with
854 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
855 	 */
856 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
857 
858 	/*
859 	 * Some devices can't tell you much until they have been
860 	 * asked to look at the media. This quirk does this.
861 	 */
862 	if (st->quirks & ST_Q_SENSE_HELP)
863 		if ((error = st_touch_tape(st)) != 0)
864 			return (error);
865 	/*
866 	 * Load the physical device parameters
867 	 * loads: blkmin, blkmax
868 	 */
869 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
870 		return (error);
871 	/*
872 	 * Load the media dependent parameters
873 	 * includes: media_blksize,media_density,numblks
874 	 * As we have a tape in, it should be reflected here.
875 	 * If not you may need the "quirk" above.
876 	 */
877 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
878 		return (error);
879 	/*
880 	 * If we have gained a permanent density from somewhere,
881 	 * then use it in preference to the one supplied by
882 	 * default by the driver.
883 	 */
884 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
885 		st->density = st->modes[dsty].density;
886 	else
887 		st->density = st->media_density;
888 	/*
889 	 * If we have gained a permanent blocksize
890 	 * then use it in preference to the one supplied by
891 	 * default by the driver.
892 	 */
893 	st->flags &= ~ST_FIXEDBLOCKS;
894 	if (st->modeflags[dsty] &
895 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
896 		st->blksize = st->modes[dsty].blksize;
897 		if (st->blksize)
898 			st->flags |= ST_FIXEDBLOCKS;
899 	} else {
900 		if ((error = st_decide_mode(st, FALSE)) != 0)
901 			return (error);
902 	}
903 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
904 		/* ATAPI will return ENODEV for this, and this may be OK */
905 		if (error != ENODEV) {
906 			printf("%s: cannot set selected mode\n",
907 			    st->sc_dev.dv_xname);
908 			return (error);
909 		}
910 	}
911 	st->flags &= ~ST_NEW_MOUNT;
912 	st->flags |= ST_MOUNTED;
913 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
914 	st->blkno = st->fileno = (daddr_t) 0;
915 	return (0);
916 }
917 
918 /*
919  * End the present mount session.
920  * Rewind, and optionally eject the tape.
921  * Reset various flags to indicate that all new
922  * operations require another mount operation
923  */
924 static void
925 st_unmount(struct st_softc *st, boolean eject)
926 {
927 	struct scsipi_periph *periph = st->sc_periph;
928 	int nmarks;
929 
930 	if ((st->flags & ST_MOUNTED) == 0)
931 		return;
932 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
933 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
934 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
935 
936 	/*
937 	 * Section 9.3.3 of the SCSI specs states that a device shall return
938 	 * the density value specified in the last succesfull MODE SELECT
939 	 * after an unload operation, in case it is not able to
940 	 * automatically determine the density of the new medium.
941 	 *
942 	 * So we instruct the device to use the default density, which will
943 	 * prevent the use of stale density values (in particular,
944 	 * in st_touch_tape().
945 	 */
946 	st->density = 0;
947 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
948 		printf("%s: WARNING: cannot revert to default density\n",
949 			st->sc_dev.dv_xname);
950 	}
951 
952 	if (eject) {
953 		if (!(st->quirks & ST_Q_NOPREVENT)) {
954 			scsipi_prevent(periph, SPAMR_ALLOW,
955 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
956 			    XS_CTL_IGNORE_NOT_READY);
957 		}
958 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
959 		st->blkno = st->fileno = (daddr_t) -1;
960 	} else {
961 		st->blkno = st->fileno = (daddr_t) 0;
962 	}
963 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
964 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
965 }
966 
967 /*
968  * Given all we know about the device, media, mode, 'quirks' and
969  * initial operation, make a decision as to how we should be set
970  * to run (regarding blocking and EOD marks)
971  */
972 int
973 st_decide_mode(struct st_softc *st, boolean first_read)
974 {
975 
976 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
977 
978 	/*
979 	 * If the drive can only handle fixed-length blocks and only at
980 	 * one size, perhaps we should just do that.
981 	 */
982 	if (st->blkmin && (st->blkmin == st->blkmax)) {
983 		st->flags |= ST_FIXEDBLOCKS;
984 		st->blksize = st->blkmin;
985 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
986 		    ("blkmin == blkmax of %d\n", st->blkmin));
987 		goto done;
988 	}
989 	/*
990 	 * If the tape density mandates (or even suggests) use of fixed
991 	 * or variable-length blocks, comply.
992 	 */
993 	switch (st->density) {
994 	case HALFINCH_800:
995 	case HALFINCH_1600:
996 	case HALFINCH_6250:
997 	case DDS:
998 		st->flags &= ~ST_FIXEDBLOCKS;
999 		st->blksize = 0;
1000 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1001 		    ("density specified variable\n"));
1002 		goto done;
1003 	case QIC_11:
1004 	case QIC_24:
1005 	case QIC_120:
1006 	case QIC_150:
1007 	case QIC_525:
1008 	case QIC_1320:
1009 	case QIC_3095:
1010 	case QIC_3220:
1011 		st->flags |= ST_FIXEDBLOCKS;
1012 		if (st->media_blksize > 0)
1013 			st->blksize = st->media_blksize;
1014 		else
1015 			st->blksize = DEF_FIXED_BSIZE;
1016 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1017 		    ("density specified fixed\n"));
1018 		goto done;
1019 	}
1020 	/*
1021 	 * If we're about to read the tape, perhaps we should choose
1022 	 * fixed or variable-length blocks and block size according to
1023 	 * what the drive found on the tape.
1024 	 */
1025 	if (first_read &&
1026 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1027 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1028 	    (st->media_blksize == 1024))) {
1029 		if (st->media_blksize > 0)
1030 			st->flags |= ST_FIXEDBLOCKS;
1031 		else
1032 			st->flags &= ~ST_FIXEDBLOCKS;
1033 		st->blksize = st->media_blksize;
1034 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1035 		    ("Used media_blksize of %d\n", st->media_blksize));
1036 		goto done;
1037 	}
1038 	/*
1039 	 * We're getting no hints from any direction.  Choose variable-
1040 	 * length blocks arbitrarily.
1041 	 */
1042 	st->flags &= ~ST_FIXEDBLOCKS;
1043 	st->blksize = 0;
1044 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1045 	    ("Give up and default to variable mode\n"));
1046 
1047 done:
1048 	/*
1049 	 * Decide whether or not to write two file marks to signify end-
1050 	 * of-data.  Make the decision as a function of density.  If
1051 	 * the decision is not to use a second file mark, the SCSI BLANK
1052 	 * CHECK condition code will be recognized as end-of-data when
1053 	 * first read.
1054 	 * (I think this should be a by-product of fixed/variable..julian)
1055 	 */
1056 	switch (st->density) {
1057 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1058 	case QIC_11:
1059 	case QIC_24:
1060 	case QIC_120:
1061 	case QIC_150:
1062 	case QIC_525:
1063 	case QIC_1320:
1064 	case QIC_3095:
1065 	case QIC_3220:
1066 		st->flags &= ~ST_2FM_AT_EOD;
1067 		break;
1068 	default:
1069 		st->flags |= ST_2FM_AT_EOD;
1070 	}
1071 	return (0);
1072 }
1073 
1074 /*
1075  * Actually translate the requested transfer into
1076  * one the physical driver can understand
1077  * The transfer is described by a buf and will include
1078  * only one physical transfer.
1079  */
1080 static void
1081 ststrategy(struct buf *bp)
1082 {
1083 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1084 	int s;
1085 
1086 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1087 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
1088 	/*
1089 	 * If it's a null transfer, return immediatly
1090 	 */
1091 	if (bp->b_bcount == 0)
1092 		goto done;
1093 
1094 	/* If offset is negative, error */
1095 	if (bp->b_blkno < 0) {
1096 		bp->b_error = EINVAL;
1097 		goto bad;
1098 	}
1099 
1100 	/*
1101 	 * Odd sized request on fixed drives are verboten
1102 	 */
1103 	if (st->flags & ST_FIXEDBLOCKS) {
1104 		if (bp->b_bcount % st->blksize) {
1105 			printf("%s: bad request, must be multiple of %d\n",
1106 			    st->sc_dev.dv_xname, st->blksize);
1107 			bp->b_error = EIO;
1108 			goto bad;
1109 		}
1110 	}
1111 	/*
1112 	 * as are out-of-range requests on variable drives.
1113 	 */
1114 	else if (bp->b_bcount < st->blkmin ||
1115 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1116 		printf("%s: bad request, must be between %d and %d\n",
1117 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1118 		bp->b_error = EIO;
1119 		goto bad;
1120 	}
1121 	s = splbio();
1122 
1123 	/*
1124 	 * Place it in the queue of activities for this tape
1125 	 * at the end (a bit silly because we only have on user..
1126 	 * (but it could fork()))
1127 	 */
1128 	BUFQ_PUT(&st->buf_queue, bp);
1129 
1130 	/*
1131 	 * Tell the device to get going on the transfer if it's
1132 	 * not doing anything, otherwise just wait for completion
1133 	 * (All a bit silly if we're only allowing 1 open but..)
1134 	 */
1135 	ststart(st->sc_periph);
1136 
1137 	splx(s);
1138 	return;
1139 bad:
1140 	bp->b_flags |= B_ERROR;
1141 done:
1142 	/*
1143 	 * Correctly set the buf to indicate a completed xfer
1144 	 */
1145 	bp->b_resid = bp->b_bcount;
1146 	biodone(bp);
1147 	return;
1148 }
1149 
1150 /*
1151  * ststart looks to see if there is a buf waiting for the device
1152  * and that the device is not already busy. If both are true,
1153  * It dequeues the buf and creates a scsi command to perform the
1154  * transfer required. The transfer request will call scsipi_done
1155  * on completion, which will in turn call this routine again
1156  * so that the next queued transfer is performed.
1157  * The bufs are queued by the strategy routine (ststrategy)
1158  *
1159  * This routine is also called after other non-queued requests
1160  * have been made of the scsi driver, to ensure that the queue
1161  * continues to be drained.
1162  * ststart() is called at splbio
1163  */
1164 static void
1165 ststart(struct scsipi_periph *periph)
1166 {
1167 	struct st_softc *st = (void *)periph->periph_dev;
1168 	struct buf *bp;
1169 	struct scsi_rw_tape cmd;
1170 	struct scsipi_xfer *xs;
1171 	int flags, error;
1172 
1173 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1174 	/*
1175 	 * See if there is a buf to do and we are not already
1176 	 * doing one
1177 	 */
1178 	while (periph->periph_active < periph->periph_openings) {
1179 		/* if a special awaits, let it proceed first */
1180 		if (periph->periph_flags & PERIPH_WAITING) {
1181 			periph->periph_flags &= ~PERIPH_WAITING;
1182 			wakeup((caddr_t)periph);
1183 			return;
1184 		}
1185 
1186 		/*
1187 		 * If the device has been unmounted by the user
1188 		 * then throw away all requests until done.
1189 		 */
1190 		if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
1191 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
1192 			if ((bp = BUFQ_GET(&st->buf_queue)) != NULL) {
1193 				/* make sure that one implies the other.. */
1194 				periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1195 				bp->b_flags |= B_ERROR;
1196 				bp->b_error = EIO;
1197 				bp->b_resid = bp->b_bcount;
1198 				biodone(bp);
1199 				continue;
1200 			} else {
1201 				return;
1202 			}
1203 		}
1204 
1205 		if ((bp = BUFQ_PEEK(&st->buf_queue)) == NULL)
1206 			return;
1207 
1208 		/*
1209 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1210 		 */
1211 		if (st->flags & ST_FIXEDBLOCKS) {
1212 			/*
1213 			 * If we are at a filemark but have not reported it yet
1214 			 * then we should report it now
1215 			 */
1216 			if (st->flags & ST_AT_FILEMARK) {
1217 				if ((bp->b_flags & B_READ) == B_WRITE) {
1218 					/*
1219 					 * Handling of ST_AT_FILEMARK in
1220 					 * st_space will fill in the right file
1221 					 * mark count.
1222 					 * Back up over filemark
1223 					 */
1224 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1225 						BUFQ_GET(&st->buf_queue);
1226 						bp->b_flags |= B_ERROR;
1227 						bp->b_error = EIO;
1228 						biodone(bp);
1229 						continue;
1230 					}
1231 				} else {
1232 					BUFQ_GET(&st->buf_queue);
1233 					bp->b_resid = bp->b_bcount;
1234 					bp->b_error = 0;
1235 					bp->b_flags &= ~B_ERROR;
1236 					st->flags &= ~ST_AT_FILEMARK;
1237 					biodone(bp);
1238 					continue;	/* seek more work */
1239 				}
1240 			}
1241 		}
1242 		/*
1243 		 * If we are at EOM but have not reported it
1244 		 * yet then we should report it now.
1245 		 */
1246 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1247 			BUFQ_GET(&st->buf_queue);
1248 			bp->b_resid = bp->b_bcount;
1249 			if (st->flags & ST_EIO_PENDING) {
1250 				bp->b_error = EIO;
1251 				bp->b_flags |= B_ERROR;
1252 			}
1253 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1254 			biodone(bp);
1255 			continue;	/* seek more work */
1256 		}
1257 
1258 		/*
1259 		 * Fill out the scsi command
1260 		 */
1261 		memset(&cmd, 0, sizeof(cmd));
1262 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1263 		if ((bp->b_flags & B_READ) == B_WRITE) {
1264 			cmd.opcode = WRITE;
1265 			st->flags &= ~ST_FM_WRITTEN;
1266 			flags |= XS_CTL_DATA_OUT;
1267 		} else {
1268 			cmd.opcode = READ;
1269 			flags |= XS_CTL_DATA_IN;
1270 		}
1271 
1272 		/*
1273 		 * Handle "fixed-block-mode" tape drives by using the
1274 		 * block count instead of the length.
1275 		 */
1276 		if (st->flags & ST_FIXEDBLOCKS) {
1277 			cmd.byte2 |= SRW_FIXED;
1278 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1279 		} else
1280 			_lto3b(bp->b_bcount, cmd.len);
1281 
1282 		/*
1283 		 * Clear 'position updated' indicator
1284 		 */
1285 		st->flags &= ~ST_POSUPDATED;
1286 
1287 		/*
1288 		 * go ask the adapter to do all this for us
1289 		 */
1290 		xs = scsipi_make_xs(periph,
1291 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1292 		    (u_char *)bp->b_data, bp->b_bcount,
1293 		    0, ST_IO_TIME, bp, flags);
1294 		if (__predict_false(xs == NULL)) {
1295 			/*
1296 			 * out of memory. Keep this buffer in the queue, and
1297 			 * retry later.
1298 			 */
1299 			callout_reset(&st->sc_callout, hz / 2, strestart,
1300 			    periph);
1301 			return;
1302 		}
1303 		/*
1304 		 * need to dequeue the buffer before queuing the command,
1305 		 * because cdstart may be called recursively from the
1306 		 * HBA driver
1307 		 */
1308 #ifdef DIAGNOSTIC
1309 		if (BUFQ_GET(&st->buf_queue) != bp)
1310 			panic("ststart(): dequeued wrong buf");
1311 #else
1312 		BUFQ_GET(&st->buf_queue);
1313 #endif
1314 		error = scsipi_execute_xs(xs);
1315 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
1316 		KASSERT(error == 0);
1317 	} /* go back and see if we can cram more work in.. */
1318 }
1319 
1320 static void
1321 strestart(void *v)
1322 {
1323 	int s = splbio();
1324 	ststart((struct scsipi_periph *)v);
1325 	splx(s);
1326 }
1327 
1328 
1329 static void
1330 stdone(struct scsipi_xfer *xs, int error)
1331 {
1332 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1333 	struct buf *bp = xs->bp;
1334 
1335 	if (bp) {
1336 		bp->b_error = error;
1337 		bp->b_resid = xs->resid;
1338 		if (error)
1339 			bp->b_flags |= B_ERROR;
1340 
1341 		if ((bp->b_flags & B_READ) == B_WRITE)
1342 			st->flags |= ST_WRITTEN;
1343 		else
1344 			st->flags &= ~ST_WRITTEN;
1345 #if NRND > 0
1346 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
1347 #endif
1348 
1349 		if ((st->flags & ST_POSUPDATED) == 0) {
1350 			if (error) {
1351 				st->fileno = st->blkno = -1;
1352 			} else if (st->blkno != -1) {
1353 				if (st->flags & ST_FIXEDBLOCKS)
1354 					st->blkno +=
1355 					    (bp->b_bcount / st->blksize);
1356 				else
1357 					st->blkno++;
1358 			}
1359 		}
1360 
1361 		biodone(bp);
1362 	}
1363 }
1364 
1365 static int
1366 stread(dev_t dev, struct uio *uio, int iomode)
1367 {
1368 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1369 
1370 	return (physio(ststrategy, NULL, dev, B_READ,
1371 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1372 }
1373 
1374 static int
1375 stwrite(dev_t dev, struct uio *uio, int iomode)
1376 {
1377 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1378 
1379 	return (physio(ststrategy, NULL, dev, B_WRITE,
1380 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1381 }
1382 
1383 /*
1384  * Perform special action on behalf of the user;
1385  * knows about the internals of this device
1386  */
1387 static int
1388 stioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct proc *p)
1389 {
1390 	int error = 0;
1391 	int unit;
1392 	int number, nmarks, dsty;
1393 	int flags;
1394 	struct st_softc *st;
1395 	int hold_blksize;
1396 	u_int8_t hold_density;
1397 	struct mtop *mt = (struct mtop *) arg;
1398 
1399 	/*
1400 	 * Find the device that the user is talking about
1401 	 */
1402 	flags = 0;		/* give error messages, act on errors etc. */
1403 	unit = STUNIT(dev);
1404 	dsty = STDSTY(dev);
1405 	st = st_cd.cd_devs[unit];
1406 	hold_blksize = st->blksize;
1407 	hold_density = st->density;
1408 
1409 	switch ((u_int) cmd) {
1410 
1411 	case MTIOCGET: {
1412 		struct mtget *g = (struct mtget *) arg;
1413 		/*
1414 		 * (to get the current state of READONLY)
1415 		 */
1416 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1417 		if (error) {
1418 			/*
1419 			 * Ignore the error if in control mode;
1420 			 * this is mandated by st(4).
1421 			 */
1422 			if (STMODE(dev) != CTRL_MODE)
1423 				break;
1424 			error = 0;
1425 		}
1426 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1427 		memset(g, 0, sizeof(struct mtget));
1428 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1429 		g->mt_blksiz = st->blksize;
1430 		g->mt_density = st->density;
1431 		g->mt_mblksiz[0] = st->modes[0].blksize;
1432 		g->mt_mblksiz[1] = st->modes[1].blksize;
1433 		g->mt_mblksiz[2] = st->modes[2].blksize;
1434 		g->mt_mblksiz[3] = st->modes[3].blksize;
1435 		g->mt_mdensity[0] = st->modes[0].density;
1436 		g->mt_mdensity[1] = st->modes[1].density;
1437 		g->mt_mdensity[2] = st->modes[2].density;
1438 		g->mt_mdensity[3] = st->modes[3].density;
1439 		g->mt_fileno = st->fileno;
1440 		g->mt_blkno = st->blkno;
1441 		if (st->flags & ST_READONLY)
1442 			g->mt_dsreg |= MT_DS_RDONLY;
1443 		if (st->flags & ST_MOUNTED)
1444 			g->mt_dsreg |= MT_DS_MOUNTED;
1445 		g->mt_resid = st->mt_resid;
1446 		g->mt_erreg = st->mt_erreg;
1447 		/*
1448 		 * clear latched errors.
1449 		 */
1450 		st->mt_resid = 0;
1451 		st->mt_erreg = 0;
1452 		st->asc = 0;
1453 		st->ascq = 0;
1454 		break;
1455 	}
1456 	case MTIOCTOP: {
1457 
1458 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1459 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1460 			mt->mt_count));
1461 
1462 		/* compat: in U*x it is a short */
1463 		number = mt->mt_count;
1464 		switch ((short) (mt->mt_op)) {
1465 		case MTWEOF:	/* write an end-of-file record */
1466 			error = st_write_filemarks(st, number, flags);
1467 			break;
1468 		case MTBSF:	/* backward space file */
1469 			number = -number;
1470 		case MTFSF:	/* forward space file */
1471 			error = st_check_eod(st, FALSE, &nmarks, flags);
1472 			if (!error)
1473 				error = st_space(st, number - nmarks,
1474 				    SP_FILEMARKS, flags);
1475 			break;
1476 		case MTBSR:	/* backward space record */
1477 			number = -number;
1478 		case MTFSR:	/* forward space record */
1479 			error = st_check_eod(st, TRUE, &nmarks, flags);
1480 			if (!error)
1481 				error = st_space(st, number, SP_BLKS, flags);
1482 			break;
1483 		case MTREW:	/* rewind */
1484 			error = st_rewind(st, 0, flags);
1485 			break;
1486 		case MTOFFL:	/* rewind and put the drive offline */
1487 			st_unmount(st, EJECT);
1488 			break;
1489 		case MTNOP:	/* no operation, sets status only */
1490 			break;
1491 		case MTRETEN:	/* retension the tape */
1492 			error = st_load(st, LD_RETENSION, flags);
1493 			if (!error)
1494 				error = st_load(st, LD_LOAD, flags);
1495 			break;
1496 		case MTEOM:	/* forward space to end of media */
1497 			error = st_check_eod(st, FALSE, &nmarks, flags);
1498 			if (!error)
1499 				error = st_space(st, 1, SP_EOM, flags);
1500 			break;
1501 		case MTCACHE:	/* enable controller cache */
1502 			st->flags &= ~ST_DONTBUFFER;
1503 			goto try_new_value;
1504 		case MTNOCACHE:	/* disable controller cache */
1505 			st->flags |= ST_DONTBUFFER;
1506 			goto try_new_value;
1507 		case MTERASE:	/* erase volume */
1508 			error = st_erase(st, number, flags);
1509 			break;
1510 		case MTSETBSIZ:	/* Set block size for device */
1511 #ifdef	NOTYET
1512 			if (!(st->flags & ST_NEW_MOUNT)) {
1513 				uprintf("re-mount tape before changing blocksize");
1514 				error = EINVAL;
1515 				break;
1516 			}
1517 #endif
1518 			if (number == 0)
1519 				st->flags &= ~ST_FIXEDBLOCKS;
1520 			else {
1521 				if ((st->blkmin || st->blkmax) &&
1522 				    (number < st->blkmin ||
1523 				    number > st->blkmax)) {
1524 					error = EINVAL;
1525 					break;
1526 				}
1527 				st->flags |= ST_FIXEDBLOCKS;
1528 			}
1529 			st->blksize = number;
1530 			st->flags |= ST_BLOCK_SET;	/*XXX */
1531 			goto try_new_value;
1532 
1533 		case MTSETDNSTY:	/* Set density for device and mode */
1534 			/*
1535 			 * Any number >= 0 and <= 0xff is legal. Numbers
1536 			 * above 0x80 are 'vendor unique'.
1537 			 */
1538 			if (number < 0 || number > 255) {
1539 				error = EINVAL;
1540 				break;
1541 			} else
1542 				st->density = number;
1543 			goto try_new_value;
1544 
1545 		case MTCMPRESS:
1546 			error = st->ops(st, (number == 0) ?
1547 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1548 			    XS_CTL_SILENT);
1549 			break;
1550 
1551 		case MTEWARN:
1552 			if (number)
1553 				st->flags |= ST_EARLYWARN;
1554 			else
1555 				st->flags &= ~ST_EARLYWARN;
1556 			break;
1557 
1558 		default:
1559 			error = EINVAL;
1560 		}
1561 		break;
1562 	}
1563 	case MTIOCIEOT:
1564 	case MTIOCEEOT:
1565 		break;
1566 
1567 	case MTIOCRDSPOS:
1568 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1569 		break;
1570 
1571 	case MTIOCRDHPOS:
1572 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1573 		break;
1574 
1575 	case MTIOCSLOCATE:
1576 		error = st_setpos(st, 0, (u_int32_t *) arg);
1577 		break;
1578 
1579 	case MTIOCHLOCATE:
1580 		error = st_setpos(st, 1, (u_int32_t *) arg);
1581 		break;
1582 
1583 
1584 	default:
1585 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1586 					flag, p);
1587 		break;
1588 	}
1589 	return (error);
1590 /*-----------------------------*/
1591 try_new_value:
1592 	/*
1593 	 * Check that the mode being asked for is aggreeable to the
1594 	 * drive. If not, put it back the way it was.
1595 	 *
1596 	 * If in control mode, we can make (persistent) mode changes
1597 	 * even if no medium is loaded (see st(4)).
1598 	 */
1599 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1600 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1601 		/* put it back as it was */
1602 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1603 		st->density = hold_density;
1604 		st->blksize = hold_blksize;
1605 		if (st->blksize)
1606 			st->flags |= ST_FIXEDBLOCKS;
1607 		else
1608 			st->flags &= ~ST_FIXEDBLOCKS;
1609 		return (error);
1610 	}
1611 	/*
1612 	 * As the drive liked it, if we are setting a new default,
1613 	 * set it into the structures as such.
1614 	 *
1615 	 * The means for deciding this are not finalised yet- but
1616 	 * if the device was opened in Control Mode, the values
1617 	 * are persistent now across mounts.
1618 	 */
1619 	if (STMODE(dev) == CTRL_MODE) {
1620 		switch ((short) (mt->mt_op)) {
1621 		case MTSETBSIZ:
1622 			st->modes[dsty].blksize = st->blksize;
1623 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1624 			break;
1625 		case MTSETDNSTY:
1626 			st->modes[dsty].density = st->density;
1627 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1628 			break;
1629 		}
1630 	}
1631 	return (0);
1632 }
1633 
1634 /*
1635  * Do a synchronous read.
1636  */
1637 static int
1638 st_read(struct st_softc *st, char *buf, int size, int flags)
1639 {
1640 	struct scsi_rw_tape cmd;
1641 
1642 	/*
1643 	 * If it's a null transfer, return immediatly
1644 	 */
1645 	if (size == 0)
1646 		return (0);
1647 	memset(&cmd, 0, sizeof(cmd));
1648 	cmd.opcode = READ;
1649 	if (st->flags & ST_FIXEDBLOCKS) {
1650 		cmd.byte2 |= SRW_FIXED;
1651 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1652 		    cmd.len);
1653 	} else
1654 		_lto3b(size, cmd.len);
1655 	return (scsipi_command(st->sc_periph,
1656 	    (void *)&cmd, sizeof(cmd), (void *)buf, size, 0, ST_IO_TIME, NULL,
1657 	    flags | XS_CTL_DATA_IN));
1658 }
1659 
1660 /*
1661  * issue an erase command
1662  */
1663 static int
1664 st_erase(struct st_softc *st, int full, int flags)
1665 {
1666 	int tmo;
1667 	struct scsi_erase cmd;
1668 
1669 	/*
1670 	 * Full erase means set LONG bit in erase command, which asks
1671 	 * the drive to erase the entire unit.  Without this bit, we're
1672 	 * asking the drive to write an erase gap.
1673 	 */
1674 	memset(&cmd, 0, sizeof(cmd));
1675 	cmd.opcode = ERASE;
1676 	if (full) {
1677 		cmd.byte2 = SE_LONG;
1678 		tmo = ST_SPC_TIME;
1679 	} else {
1680 		tmo = ST_IO_TIME;
1681 	}
1682 
1683 	/*
1684 	 * XXX We always do this asynchronously, for now, unless the device
1685 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1686 	 * want to (eventually) to it synchronously?
1687 	 */
1688 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1689 		cmd.byte2 |= SE_IMMED;
1690 
1691 	return (scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1692 	    ST_RETRIES, tmo, NULL, flags));
1693 }
1694 
1695 /*
1696  * skip N blocks/filemarks/seq filemarks/eom
1697  */
1698 static int
1699 st_space(struct st_softc *st, int number, u_int what, int flags)
1700 {
1701 	struct scsi_space cmd;
1702 	int error;
1703 
1704 	switch (what) {
1705 	case SP_BLKS:
1706 		if (st->flags & ST_PER_ACTION) {
1707 			if (number > 0) {
1708 				st->flags &= ~ST_PER_ACTION;
1709 				return (EIO);
1710 			} else if (number < 0) {
1711 				if (st->flags & ST_AT_FILEMARK) {
1712 					/*
1713 					 * Handling of ST_AT_FILEMARK
1714 					 * in st_space will fill in the
1715 					 * right file mark count.
1716 					 */
1717 					error = st_space(st, 0, SP_FILEMARKS,
1718 					    flags);
1719 					if (error)
1720 						return (error);
1721 				}
1722 				if (st->flags & ST_BLANK_READ) {
1723 					st->flags &= ~ST_BLANK_READ;
1724 					return (EIO);
1725 				}
1726 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1727 			}
1728 		}
1729 		break;
1730 	case SP_FILEMARKS:
1731 		if (st->flags & ST_EIO_PENDING) {
1732 			if (number > 0) {
1733 				/* pretend we just discovered the error */
1734 				st->flags &= ~ST_EIO_PENDING;
1735 				return (EIO);
1736 			} else if (number < 0) {
1737 				/* back away from the error */
1738 				st->flags &= ~ST_EIO_PENDING;
1739 			}
1740 		}
1741 		if (st->flags & ST_AT_FILEMARK) {
1742 			st->flags &= ~ST_AT_FILEMARK;
1743 			number--;
1744 		}
1745 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1746 			/* back away from unwritten tape */
1747 			st->flags &= ~ST_BLANK_READ;
1748 			number++;	/* XXX dubious */
1749 		}
1750 		break;
1751 	case SP_EOM:
1752 		if (st->flags & ST_EOM_PENDING) {
1753 			/* we're already there */
1754 			st->flags &= ~ST_EOM_PENDING;
1755 			return (0);
1756 		}
1757 		if (st->flags & ST_EIO_PENDING) {
1758 			/* pretend we just discovered the error */
1759 			st->flags &= ~ST_EIO_PENDING;
1760 			return (EIO);
1761 		}
1762 		if (st->flags & ST_AT_FILEMARK)
1763 			st->flags &= ~ST_AT_FILEMARK;
1764 		break;
1765 	}
1766 	if (number == 0)
1767 		return (0);
1768 
1769 	memset(&cmd, 0, sizeof(cmd));
1770 	cmd.opcode = SPACE;
1771 	cmd.byte2 = what;
1772 	_lto3b(number, cmd.number);
1773 
1774 	st->flags &= ~ST_POSUPDATED;
1775 	st->last_ctl_resid = 0;
1776 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1777 	    0, ST_SPC_TIME, NULL, flags);
1778 
1779 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1780 		number = number - st->last_ctl_resid;
1781 		if (what == SP_BLKS) {
1782 			if (st->blkno != -1) {
1783 				st->blkno += number;
1784 			}
1785 		} else if (what == SP_FILEMARKS) {
1786 			if (st->fileno != -1) {
1787 				st->fileno += number;
1788 				if (number > 0) {
1789 					st->blkno = 0;
1790 				} else if (number < 0) {
1791 					st->blkno = -1;
1792 				}
1793 			}
1794 		} else if (what == SP_EOM) {
1795 			/*
1796 			 * This loses us relative position.
1797 			 */
1798 			st->fileno = st->blkno = -1;
1799 		}
1800 	}
1801 	return (error);
1802 }
1803 
1804 /*
1805  * write N filemarks
1806  */
1807 static int
1808 st_write_filemarks(struct st_softc *st, int number, int flags)
1809 {
1810 	int error;
1811 	struct scsi_write_filemarks cmd;
1812 
1813 	/*
1814 	 * It's hard to write a negative number of file marks.
1815 	 * Don't try.
1816 	 */
1817 	if (number < 0)
1818 		return (EINVAL);
1819 	switch (number) {
1820 	case 0:		/* really a command to sync the drive's buffers */
1821 		break;
1822 	case 1:
1823 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1824 			st->flags &= ~ST_WRITTEN;
1825 		else
1826 			st->flags |= ST_FM_WRITTEN;
1827 		st->flags &= ~ST_PER_ACTION;
1828 		break;
1829 	default:
1830 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1831 	}
1832 
1833 	memset(&cmd, 0, sizeof(cmd));
1834 	cmd.opcode = WRITE_FILEMARKS;
1835 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1836 		cmd.byte2 = SR_IMMED;
1837 	/*
1838 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1839 	 * WRITE_FILEMARKS is still used to flush the buffer
1840 	 */
1841 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1842 		_lto3b(number, cmd.number);
1843 
1844 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1845 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1846 	    0, ST_IO_TIME * 4, NULL, flags);
1847 	if (error == 0 && st->fileno != -1) {
1848 		st->fileno += number;
1849 	}
1850 	return (error);
1851 }
1852 
1853 /*
1854  * Make sure the right number of file marks is on tape if the
1855  * tape has been written.  If the position argument is true,
1856  * leave the tape positioned where it was originally.
1857  *
1858  * nmarks returns the number of marks to skip (or, if position
1859  * true, which were skipped) to get back original position.
1860  */
1861 static int
1862 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
1863 {
1864 	int error;
1865 
1866 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1867 	default:
1868 		*nmarks = 0;
1869 		return (0);
1870 	case ST_WRITTEN:
1871 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1872 		*nmarks = 1;
1873 		break;
1874 	case ST_WRITTEN | ST_2FM_AT_EOD:
1875 		*nmarks = 2;
1876 	}
1877 	error = st_write_filemarks(st, *nmarks, flags);
1878 	if (position && !error)
1879 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1880 	return (error);
1881 }
1882 
1883 /*
1884  * load/unload/retension
1885  */
1886 static int
1887 st_load(struct st_softc *st, u_int type, int flags)
1888 {
1889 	int error;
1890 	struct scsi_load cmd;
1891 
1892 	if (type != LD_LOAD) {
1893 		int nmarks;
1894 
1895 		error = st_check_eod(st, FALSE, &nmarks, flags);
1896 		if (error) {
1897 			printf("%s: failed to write closing filemarks at "
1898 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1899 			return (error);
1900 		}
1901 	}
1902 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1903 		if (type == LD_LOAD) {
1904 			/*
1905 			 * If we ignore loads, at least we should try a rewind.
1906 			 */
1907 			return st_rewind(st, 0, flags);
1908 		}
1909 		/* otherwise, we should do what's asked of us */
1910 	}
1911 
1912 	memset(&cmd, 0, sizeof(cmd));
1913 	cmd.opcode = LOAD;
1914 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1915 		cmd.byte2 = SR_IMMED;
1916 	cmd.how = type;
1917 
1918 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1919 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
1920 	if (error) {
1921 		printf("%s: error %d in st_load (op %d)\n",
1922 		    st->sc_dev.dv_xname, error, type);
1923 	}
1924 	return (error);
1925 }
1926 
1927 /*
1928  *  Rewind the device
1929  */
1930 static int
1931 st_rewind(struct st_softc *st, u_int immediate, int flags)
1932 {
1933 	struct scsi_rewind cmd;
1934 	int error;
1935 	int nmarks;
1936 
1937 	error = st_check_eod(st, FALSE, &nmarks, flags);
1938 	if (error) {
1939 		printf("%s: failed to write closing filemarks at "
1940 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1941 		return (error);
1942 	}
1943 	st->flags &= ~ST_PER_ACTION;
1944 
1945 	/*
1946 	 * ATAPI tapes always need immediate to be set
1947 	 */
1948 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1949 		immediate = SR_IMMED;
1950 
1951 	memset(&cmd, 0, sizeof(cmd));
1952 	cmd.opcode = REWIND;
1953 	cmd.byte2 = immediate;
1954 
1955 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1956 	    ST_RETRIES, immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
1957 	if (error) {
1958 		printf("%s: error %d trying to rewind\n",
1959 		    st->sc_dev.dv_xname, error);
1960 		/* lost position */
1961 		st->fileno = st->blkno = -1;
1962 	} else {
1963 		st->fileno = st->blkno = 0;
1964 	}
1965 	return (error);
1966 }
1967 
1968 static int
1969 st_rdpos(struct st_softc *st, int hard, u_int32_t *blkptr)
1970 {
1971 	int error;
1972 	u_int8_t posdata[20];
1973 	struct scsi_tape_read_position cmd;
1974 
1975 	/*
1976 	 * We try and flush any buffered writes here if we were writing
1977 	 * and we're trying to get hardware block position. It eats
1978 	 * up performance substantially, but I'm wary of drive firmware.
1979 	 *
1980 	 * I think that *logical* block position is probably okay-
1981 	 * but hardware block position might have to wait for data
1982 	 * to hit media to be valid. Caveat Emptor.
1983 	 */
1984 
1985 	if (hard && (st->flags & ST_WRITTEN)) {
1986 		/*
1987 		 * First flush any pending writes...
1988 		 */
1989 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
1990 		/*
1991 		 * The latter case is for 'write protected' tapes
1992 		 * which are too stupid to recognize a zero count
1993 		 * for writing filemarks as a no-op.
1994 		 */
1995 		if (error != 0 && error != EACCES && error != EROFS)
1996 			return (error);
1997 	}
1998 
1999 	memset(&cmd, 0, sizeof(cmd));
2000 	memset(&posdata, 0, sizeof(posdata));
2001 	cmd.opcode = READ_POSITION;
2002 	if (hard)
2003 		cmd.byte1 = 1;
2004 
2005 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
2006 	    (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
2007 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
2008 
2009 	if (error == 0) {
2010 #if	0
2011 		printf("posdata:");
2012 		for (hard = 0; hard < sizeof(posdata); hard++)
2013 			printf("%02x ", posdata[hard] & 0xff);
2014 		printf("\n");
2015 #endif
2016 		if (posdata[0] & 0x4)	/* Block Position Unknown */
2017 			error = EINVAL;
2018 		else
2019 			*blkptr = _4btol(&posdata[4]);
2020 	}
2021 	return (error);
2022 }
2023 
2024 static int
2025 st_setpos(struct st_softc *st, int hard, u_int32_t *blkptr)
2026 {
2027 	int error;
2028 	struct scsi_tape_locate cmd;
2029 
2030 	/*
2031 	 * We used to try and flush any buffered writes here.
2032 	 * Now we push this onto user applications to either
2033 	 * flush the pending writes themselves (via a zero count
2034 	 * WRITE FILEMARKS command) or they can trust their tape
2035 	 * drive to do this correctly for them.
2036 	 *
2037 	 * There are very ugly performance limitations otherwise.
2038 	 */
2039 
2040 	memset(&cmd, 0, sizeof(cmd));
2041 	cmd.opcode = LOCATE;
2042 	if (hard)
2043 		cmd.byte2 = 1 << 2;
2044 	_lto4b(*blkptr, cmd.blkaddr);
2045 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
2046 	    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 scsi_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->response_code & SSD_RCODE_VALID) == 0 ||
2078 	    (SSD_RCODE(sense->response_code) != SSD_RCODE_CURRENT &&
2079 	     SSD_RCODE(sense->response_code) != SSD_RCODE_DEFERRED))
2080 		return (retval);
2081 
2082 	if (sense->response_code & SSD_RCODE_VALID)
2083 		info = _4btol(sense->info);
2084 	else
2085 		info = (st->flags & ST_FIXEDBLOCKS) ?
2086 		    xs->datalen / st->blksize : xs->datalen;
2087 	key = SSD_SENSE_KEY(sense->flags);
2088 	st->mt_erreg = key;
2089 	st->asc = sense->asc;
2090 	st->ascq = sense->ascq;
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->response_code & SSD_RCODE_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->response_code & SSD_RCODE_VALID) != 0) {
2291 			switch (key) {
2292 			case SKEY_NOT_READY:
2293 			case SKEY_ILLEGAL_REQUEST:
2294 			case SKEY_UNIT_ATTENTION:
2295 			case SKEY_DATA_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->csi[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