xref: /netbsd-src/sys/dev/scsipi/st.c (revision b7ae68fde0d8ef1c03714e8bbb1ee7c6118ea93b)
1 /*	$NetBSD: st.c,v 1.192 2006/08/23 17:19:32 christos 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 1.192 2006/08/23 17:19:32 christos 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 #include <sys/iostat.h>
80 #include <sys/sysctl.h>
81 
82 #include <dev/scsipi/scsi_spc.h>
83 #include <dev/scsipi/scsipi_all.h>
84 #include <dev/scsipi/scsi_all.h>
85 #include <dev/scsipi/scsi_tape.h>
86 #include <dev/scsipi/scsipiconf.h>
87 #include <dev/scsipi/scsipi_base.h>
88 #include <dev/scsipi/stvar.h>
89 
90 /* Defines for device specific stuff */
91 #define DEF_FIXED_BSIZE  512
92 
93 #define STMODE(z)	( minor(z)       & 0x03)
94 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
95 #define STUNIT(z)	((minor(z) >> 4)       )
96 #define STNMINOR	16
97 
98 #define NORMAL_MODE	0
99 #define NOREW_MODE	1
100 #define EJECT_MODE	2
101 #define CTRL_MODE	3
102 
103 #define	FALSE		0
104 #define	TRUE		1
105 
106 #ifndef		ST_MOUNT_DELAY
107 #define		ST_MOUNT_DELAY		0
108 #endif
109 
110 static dev_type_open(stopen);
111 static dev_type_close(stclose);
112 static dev_type_read(stread);
113 static dev_type_write(stwrite);
114 static dev_type_ioctl(stioctl);
115 static dev_type_strategy(ststrategy);
116 static dev_type_dump(stdump);
117 
118 const struct bdevsw st_bdevsw = {
119 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
120 };
121 
122 const struct cdevsw st_cdevsw = {
123 	stopen, stclose, stread, stwrite, stioctl,
124 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
125 };
126 
127 /*
128  * Define various devices that we know mis-behave in some way,
129  * and note how they are bad, so we can correct for them
130  */
131 
132 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
133 	{{T_SEQUENTIAL, T_REMOV,
134 	 "        ", "                ", "    "}, {0, 0, {
135 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
136 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
137 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
138 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
139 	}}},
140 	{{T_SEQUENTIAL, T_REMOV,
141 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
142 		{0, 0, 0},				/* minor 0-3 */
143 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
144 		{0, 0, QIC_150},			/* minor 8-11 */
145 		{0, 0, QIC_120}				/* minor 12-15 */
146 	}}},
147  	{{T_SEQUENTIAL, T_REMOV,
148  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
149 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
150 		{0, 0, QIC_525},			/* minor 4-7 */
151 		{0, 0, QIC_150},			/* minor 8-11 */
152 		{0, 0, QIC_120}				/* minor 12-15 */
153 	}}},
154 	{{T_SEQUENTIAL, T_REMOV,
155 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
156 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
157 		{0, 0, 0},				/* minor 4-7 */
158 		{0, 0, 0},				/* minor 8-11 */
159 		{0, 0, 0}				/* minor 12-15 */
160 	}}},
161 	/*
162 	 * lacking a manual for the 4200, it's not clear what the
163 	 * specific density codes should be- the device is a 2.5GB
164 	 * capable QIC drive, those density codes aren't readily
165 	 * availabel. The 'default' will just have to do.
166 	 */
167  	{{T_SEQUENTIAL, T_REMOV,
168  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
169 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
170 		{0, 0, QIC_525},			/* minor 4-7 */
171 		{0, 0, QIC_150},			/* minor 8-11 */
172 		{0, 0, QIC_120}				/* minor 12-15 */
173 	}}},
174 	/*
175 	 * At least -005 and -007 need this.  I'll assume they all do unless I
176 	 * hear otherwise.  - mycroft, 31MAR1994
177 	 */
178 	{{T_SEQUENTIAL, T_REMOV,
179 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
180 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
181 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
182 		{0, 0, QIC_150},			/* minor 8-11 */
183 		{0, 0, QIC_120}				/* minor 12-15 */
184 	}}},
185 	/*
186 	 * One user reports that this works for his tape drive.  It probably
187 	 * needs more work.  - mycroft, 09APR1994
188 	 */
189 	{{T_SEQUENTIAL, T_REMOV,
190 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
191 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
192 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
193 		{0, 0, QIC_150},			/* minor 8-11 */
194 		{0, 0, QIC_120}				/* minor 12-15 */
195 	}}},
196 	{{T_SEQUENTIAL, T_REMOV,
197 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
198 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
199 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
200 		{0, 0, QIC_150},			/* minor 8-11 */
201 		{0, 0, QIC_120}				/* minor 12-15 */
202 	}}},
203 	{{T_SEQUENTIAL, T_REMOV,
204 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
205 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
206 		{0, 0, QIC_150},			/* minor 4-7 */
207 		{0, 0, QIC_120},			/* minor 8-11 */
208 		{0, 0, QIC_24}				/* minor 12-15 */
209 	}}},
210 	{{T_SEQUENTIAL, T_REMOV,
211 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
212 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
213 		{0, 0, QIC_150},			/* minor 4-7 */
214 		{0, 0, QIC_120},			/* minor 8-11 */
215 		{0, 0, QIC_24}				/* minor 12-15 */
216 	}}},
217 	{{T_SEQUENTIAL, T_REMOV,
218 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
219 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
220 		{0, 0, QIC_11},				/* minor 4-7 */
221 		{0, 0, QIC_24},				/* minor 8-11 */
222 		{0, 0, QIC_24}				/* minor 12-15 */
223 	}}},
224 	{{T_SEQUENTIAL, T_REMOV,
225 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
226 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
227 		{0, 0, QIC_24},				/* minor 4-7 */
228 		{0, 0, QIC_120},			/* minor 8-11 */
229 		{0, 0, QIC_150}				/* minor 12-15 */
230 	}}},
231 	{{T_SEQUENTIAL, T_REMOV,
232 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
233 		{0, 0, 0},				/* minor 0-3 */
234 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
235 		{0, 0, QIC_150},			/* minor 8-11 */
236 		{0, 0, QIC_120}				/* minor 12-15 */
237 	}}},
238 	{{T_SEQUENTIAL, T_REMOV,
239 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
240 		{0, 0, 0},				/* minor 0-3 */
241 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
242 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
243 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
244 	}}},
245 	{{T_SEQUENTIAL, T_REMOV,
246 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
247 		{0, 0, 0},				/* minor 0-3 */
248 		{0, 0, 0},				/* minor 4-7 */
249 		{0, 0, 0},				/* minor 8-11 */
250 		{0, 0, 0}				/* minor 12-15 */
251 	}}},
252 	{{T_SEQUENTIAL, T_REMOV,
253 	 "STK",      "9490",             ""},
254 				{ST_Q_FORCE_BLKSIZE, 0, {
255 		{0, 0, 0},				/* minor 0-3 */
256 		{0, 0, 0},				/* minor 4-7 */
257 		{0, 0, 0},				/* minor 8-11 */
258 		{0, 0, 0}				/* minor 12-15 */
259 	}}},
260 	{{T_SEQUENTIAL, T_REMOV,
261 	 "STK",      "SD-3",             ""},
262 				{ST_Q_FORCE_BLKSIZE, 0, {
263 		{0, 0, 0},				/* minor 0-3 */
264 		{0, 0, 0},				/* minor 4-7 */
265 		{0, 0, 0},				/* minor 8-11 */
266 		{0, 0, 0}				/* minor 12-15 */
267 	}}},
268 	{{T_SEQUENTIAL, T_REMOV,
269 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
270 		{0, 0, 0},				/* minor 0-3 */
271 		{0, 0, 0},				/* minor 4-7 */
272 		{0, 0, 0},				/* minor 8-11 */
273 		{0, 0, 0}				/* minor 12-15 */
274 	}}},
275 	{{T_SEQUENTIAL, T_REMOV,
276 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
277 		{0, 0, QIC_3095},			/* minor 0-3 */
278 		{0, 0, QIC_3095},			/* minor 4-7 */
279 		{0, 0, QIC_3095},			/* minor 8-11 */
280 		{0, 0, QIC_3095},			/* minor 12-15 */
281 	}}},
282 #if 0
283 	{{T_SEQUENTIAL, T_REMOV,
284 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
285 		{0, 0, 0},				/* minor 0-3 */
286 		{0, 0, 0},				/* minor 4-7 */
287 		{0, 0, 0},				/* minor 8-11 */
288 		{0, 0, 0}				/* minor 12-15 */
289 	}}},
290 #endif
291 	{{T_SEQUENTIAL, T_REMOV,
292 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
293 		{0, 0, 0},			        /* minor 0-3 */
294 		{0, 0, 0},			        /* minor 4-7 */
295 		{0, 0, 0},			        /* minor 8-11 */
296 		{0, 0, 0}			        /* minor 12-15 */
297 	}}},
298 	{{T_SEQUENTIAL, T_REMOV,
299 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
300 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
301 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
302 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
303 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
304 	}}},
305 	{{T_SEQUENTIAL, T_REMOV,
306 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
307 		{0, 0, 0},                              /* minor 0-3 */
308 		{0, 0, 0},                              /* minor 4-7 */
309 		{0, 0, 0},                              /* minor 8-11 */
310 		{0, 0, 0}                               /* minor 12-15 */
311 	}}},
312 	{{T_SEQUENTIAL, T_REMOV,
313 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
314 		{0, 0, 0},			       /* minor 0-3 */
315 		{0, 0, 0},			       /* minor 4-7 */
316 		{0, 0, 0},			       /* minor 8-11 */
317 		{0, 0, 0}			       /* minor 12-15 */
318 	}}},
319 };
320 
321 #define NOEJECT 0
322 #define EJECT 1
323 
324 static void	st_identify_drive(struct st_softc *,
325 		    struct scsipi_inquiry_pattern *);
326 static void	st_loadquirks(struct st_softc *);
327 static int	st_mount_tape(dev_t, int);
328 static void	st_unmount(struct st_softc *, boolean);
329 static int	st_decide_mode(struct st_softc *, boolean);
330 static void	ststart(struct scsipi_periph *);
331 static void	strestart(void *);
332 static void	stdone(struct scsipi_xfer *, int);
333 static int	st_read(struct st_softc *, char *, int, int);
334 static int	st_space(struct st_softc *, int, u_int, int);
335 static int	st_write_filemarks(struct st_softc *, int, int);
336 static int	st_check_eod(struct st_softc *, boolean, int *, int);
337 static int	st_load(struct st_softc *, u_int, int);
338 static int	st_rewind(struct st_softc *, u_int, int);
339 static int	st_interpret_sense(struct scsipi_xfer *);
340 static int	st_touch_tape(struct st_softc *);
341 static int	st_erase(struct st_softc *, int full, int flags);
342 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
343 static int	st_setpos(struct st_softc *, int, u_int32_t *);
344 
345 static const struct scsipi_periphsw st_switch = {
346 	st_interpret_sense,
347 	ststart,
348 	NULL,
349 	stdone
350 };
351 
352 #if	defined(ST_ENABLE_EARLYWARN)
353 #define	ST_INIT_FLAGS	ST_EARLYWARN
354 #else
355 #define	ST_INIT_FLAGS	0
356 #endif
357 
358 /*
359  * The routine called by the low level scsi routine when it discovers
360  * A device suitable for this driver
361  */
362 void
363 stattach(struct device *parent, struct st_softc *st, void *aux)
364 {
365 	struct scsipibus_attach_args *sa = aux;
366 	struct scsipi_periph *periph = sa->sa_periph;
367 
368 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
369 
370 	/*
371 	 * Store information needed to contact our base driver
372 	 */
373 	st->sc_periph = periph;
374 	periph->periph_dev = &st->sc_dev;
375 	periph->periph_switch = &st_switch;
376 
377 	/*
378 	 * Set initial flags
379 	 */
380 
381 	st->flags = ST_INIT_FLAGS;
382 
383 	/*
384 	 * Set up the buf queue for this device
385 	 */
386 	bufq_alloc(&st->buf_queue, "fcfs", 0);
387 
388 	callout_init(&st->sc_callout);
389 
390 	/*
391 	 * Check if the drive is a known criminal and take
392 	 * Any steps needed to bring it into line
393 	 */
394 	st_identify_drive(st, &sa->sa_inqbuf);
395 	/*
396 	 * Use the subdriver to request information regarding the drive.
397 	 */
398 	printf("\n");
399 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "quirks apply, " : "");
400 	if (scsipi_test_unit_ready(periph,
401 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
402 	    st->ops(st, ST_OPS_MODESENSE,
403 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
404 		printf("drive empty\n");
405 	else {
406 		printf("density code %d, ", st->media_density);
407 		if (st->media_blksize > 0)
408 			printf("%d-byte", st->media_blksize);
409 		else
410 			printf("variable");
411 		printf(" blocks, write-%s\n",
412 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
413 	}
414 
415 	st->stats = iostat_alloc(IOSTAT_TAPE, parent, st->sc_dev.dv_xname);
416 
417 #if NRND > 0
418 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
419 			  RND_TYPE_TAPE, 0);
420 #endif
421 }
422 
423 int
424 stactivate(struct device *self, enum devact act)
425 {
426 	int rv = 0;
427 
428 	switch (act) {
429 	case DVACT_ACTIVATE:
430 		rv = EOPNOTSUPP;
431 		break;
432 
433 	case DVACT_DEACTIVATE:
434 		/*
435 		 * Nothing to do; we key off the device's DVF_ACTIVE.
436 		 */
437 		break;
438 	}
439 	return (rv);
440 }
441 
442 int
443 stdetach(struct device *self, int flags)
444 {
445 	struct st_softc *st = device_private(self);
446 	int s, bmaj, cmaj, mn;
447 
448 	/* locate the major number */
449 	bmaj = bdevsw_lookup_major(&st_bdevsw);
450 	cmaj = cdevsw_lookup_major(&st_cdevsw);
451 
452 	/* kill any pending restart */
453 	callout_stop(&st->sc_callout);
454 
455 	s = splbio();
456 
457 	/* Kill off any queued buffers. */
458 	bufq_drain(st->buf_queue);
459 
460 	bufq_free(st->buf_queue);
461 
462 	/* Kill off any pending commands. */
463 	scsipi_kill_pending(st->sc_periph);
464 
465 	splx(s);
466 
467 	/* Nuke the vnodes for any open instances */
468 	mn = STUNIT(device_unit(self));
469 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
470 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
471 
472 	iostat_free(st->stats);
473 
474 #if NRND > 0
475 	/* Unhook the entropy source. */
476 	rnd_detach_source(&st->rnd_source);
477 #endif
478 
479 	return (0);
480 }
481 
482 /*
483  * Use the inquiry routine in 'scsi_base' to get drive info so we can
484  * Further tailor our behaviour.
485  */
486 static void
487 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
488 {
489 	const struct st_quirk_inquiry_pattern *finger;
490 	int priority;
491 
492 	finger = scsipi_inqmatch(inqbuf,
493 	    st_quirk_patterns,
494 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
495 	    sizeof(st_quirk_patterns[0]), &priority);
496 	if (priority != 0) {
497 		st->quirkdata = &finger->quirkdata;
498 		st->drive_quirks = finger->quirkdata.quirks;
499 		st->quirks = finger->quirkdata.quirks;	/* start value */
500 		st->page_0_size = finger->quirkdata.page_0_size;
501 		st_loadquirks(st);
502 	}
503 }
504 
505 /*
506  * initialise the subdevices to the default (QUIRK) state.
507  * this will remove any setting made by the system operator or previous
508  * operations.
509  */
510 static void
511 st_loadquirks(struct st_softc *st)
512 {
513 	int i;
514 	const struct	modes *mode;
515 	struct	modes *mode2;
516 
517 	mode = st->quirkdata->modes;
518 	mode2 = st->modes;
519 	for (i = 0; i < 4; i++) {
520 		memset(mode2, 0, sizeof(struct modes));
521 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
522 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
523 		    DENSITY_SET_BY_USER);
524 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
525 			mode2->blksize = mode->blksize;
526 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
527 		}
528 		if (mode->density) {
529 			mode2->density = mode->density;
530 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
531 		}
532 		mode2->quirks |= mode->quirks;
533 		mode++;
534 		mode2++;
535 	}
536 }
537 
538 /*
539  * open the device.
540  */
541 static int
542 stopen(dev_t dev, int flags, int mode, struct lwp *l)
543 {
544 	u_int stmode, dsty;
545 	int error, sflags, unit, tries, ntries;
546 	struct st_softc *st;
547 	struct scsipi_periph *periph;
548 	struct scsipi_adapter *adapt;
549 
550 	unit = STUNIT(dev);
551 	if (unit >= st_cd.cd_ndevs)
552 		return (ENXIO);
553 	st = st_cd.cd_devs[unit];
554 	if (st == NULL)
555 		return (ENXIO);
556 
557 	stmode = STMODE(dev);
558 	dsty = STDSTY(dev);
559 
560 	periph = st->sc_periph;
561 	adapt = periph->periph_channel->chan_adapter;
562 
563 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
564 	    unit, st_cd.cd_ndevs));
565 
566 
567 	/*
568 	 * Only allow one at a time
569 	 */
570 	if (periph->periph_flags & PERIPH_OPEN) {
571 		printf("%s: already open\n", st->sc_dev.dv_xname);
572 		return (EBUSY);
573 	}
574 
575 	if ((error = scsipi_adapter_addref(adapt)) != 0)
576 		return (error);
577 
578 	/*
579 	 * clear any latched errors.
580 	 */
581 	st->mt_resid = 0;
582 	st->mt_erreg = 0;
583 	st->asc = 0;
584 	st->ascq = 0;
585 
586 	/*
587 	 * Catch any unit attention errors. Be silent about this
588 	 * unless we're already mounted. We ignore media change
589 	 * if we're in control mode or not mounted yet.
590 	 */
591 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
592 #ifdef SCSIDEBUG
593 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
594 #else
595 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
596 #endif
597 	} else
598 		sflags = 0;
599 
600 	/*
601 	 * If we're already mounted or we aren't configured for
602 	 * a mount delay, only try a test unit ready once. Otherwise,
603 	 * try up to ST_MOUNT_DELAY times with a rest interval of
604 	 * one second between each try.
605 	 */
606 
607 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
608 		ntries = 1;
609 	} else {
610 		ntries = ST_MOUNT_DELAY;
611 	}
612 
613 	for (error = tries = 0; tries < ntries; tries++) {
614 		int slpintr, oflags;
615 
616 		/*
617 		 * If we had no error, or we're opening the control mode
618 		 * device, we jump out right away.
619 		 */
620 
621 		error = scsipi_test_unit_ready(periph, sflags);
622 		if (error == 0 || stmode == CTRL_MODE) {
623 			break;
624 		}
625 
626 		/*
627 		 * We had an error.
628 		 *
629 		 * If we're already mounted or we aren't configured for
630 		 * a mount delay, or the error isn't a NOT READY error,
631 		 * skip to the error exit now.
632 		 */
633 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
634 		    (st->mt_key != SKEY_NOT_READY)) {
635 			goto bad;
636 		}
637 
638 		/*
639 		 * clear any latched errors.
640 		 */
641 		st->mt_resid = 0;
642 		st->mt_erreg = 0;
643 		st->asc = 0;
644 		st->ascq = 0;
645 
646 		/*
647 		 * Fake that we have the device open so
648 		 * we block other apps from getting in.
649 		 */
650 
651 		oflags = periph->periph_flags;
652 		periph->periph_flags |= PERIPH_OPEN;
653 
654 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
655 
656 		periph->periph_flags = oflags;	/* restore flags */
657 		if (slpintr) {
658 			goto bad;
659 		}
660 	}
661 
662 
663 	/*
664 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
665 	 * been opened to set defaults and perform other, usually non-I/O
666 	 * related, operations. In this case, do a quick check to see
667 	 * whether the unit actually had a tape loaded (this will be known
668 	 * as to whether or not we got a NOT READY for the above
669 	 * unit attention). If a tape is there, go do a mount sequence.
670 	 */
671 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
672 		periph->periph_flags |= PERIPH_OPEN;
673 		return (0);
674 	}
675 
676 	/*
677 	 * If we get this far and had an error set, that means we failed
678 	 * to pass the 'test unit ready' test for the non-controlmode device,
679 	 * so we bounce the open.
680 	 */
681 
682 	if (error)
683 		return (error);
684 
685 	/*
686 	 * Else, we're now committed to saying we're open.
687 	 */
688 
689 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
690 
691 	/*
692 	 * If it's a different mode, or if the media has been
693 	 * invalidated, unmount the tape from the previous
694 	 * session but continue with open processing
695 	 */
696 	if (st->last_dsty != dsty ||
697 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
698 		st_unmount(st, NOEJECT);
699 
700 	/*
701 	 * If we are not mounted, then we should start a new
702 	 * mount session.
703 	 */
704 	if (!(st->flags & ST_MOUNTED)) {
705 		if ((error = st_mount_tape(dev, flags)) != 0)
706 			goto bad;
707 		st->last_dsty = dsty;
708 	}
709 	if (!(st->quirks & ST_Q_NOPREVENT)) {
710 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
711 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
712 	}
713 
714 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
715 	return (0);
716 
717 bad:
718 	st_unmount(st, NOEJECT);
719 	scsipi_adapter_delref(adapt);
720 	periph->periph_flags &= ~PERIPH_OPEN;
721 	return (error);
722 }
723 
724 /*
725  * close the device.. only called if we are the LAST
726  * occurence of an open device
727  */
728 static int
729 stclose(dev_t dev, int flags, int mode, struct lwp *l)
730 {
731 	int stxx, error = 0;
732 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
733 	struct scsipi_periph *periph = st->sc_periph;
734 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
735 
736 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
737 
738 	/*
739 	 * Make sure that a tape opened in write-only mode will have
740 	 * file marks written on it when closed, even if not written to.
741 	 *
742 	 * This is for SUN compatibility. Actually, the Sun way of
743 	 * things is to:
744 	 *
745 	 *	only write filemarks if there are fmks to be written and
746 	 *   		- open for write (possibly read/write)
747 	 *		- the last operation was a write
748 	 * 	or:
749 	 *		- opened for wronly
750 	 *		- no data was written (including filemarks)
751 	 */
752 
753 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
754 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
755 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
756 		int nm;
757 		error = st_check_eod(st, FALSE, &nm, 0);
758 	}
759 
760 	/*
761 	 * Allow robots to eject tape if needed.
762 	 */
763 	scsipi_prevent(periph, SPAMR_ALLOW,
764 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
765 
766 	switch (STMODE(dev)) {
767 	case NORMAL_MODE:
768 		st_unmount(st, NOEJECT);
769 		break;
770 	case NOREW_MODE:
771 	case CTRL_MODE:
772 		/*
773 		 * Leave mounted unless media seems to have been removed.
774 		 *
775 		 * Otherwise, if we're to terminate a tape with more than one
776 		 * filemark [ and because we're not rewinding here ], backspace
777 		 * one filemark so that later appends will see an unbroken
778 		 * sequence of:
779 		 *
780 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
781 		 */
782 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
783 			st_unmount(st, NOEJECT);
784 		} else if (error == 0) {
785 			/*
786 			 * ST_WRITTEN was preserved from above.
787 			 *
788 			 * All we need to know here is:
789 			 *
790 			 *	Were we writing this tape and was the last
791 			 *	operation a write?
792 			 *
793 			 *	Are there supposed to be 2FM at EOD?
794 			 *
795 			 * If both statements are true, then we backspace
796 			 * one filemark.
797 			 */
798 			stxx |= (st->flags & ST_2FM_AT_EOD);
799 			if ((flags & FWRITE) != 0 &&
800 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
801 				error = st_space(st, -1, SP_FILEMARKS, 0);
802 			}
803 		}
804 		break;
805 	case EJECT_MODE:
806 		st_unmount(st, EJECT);
807 		break;
808 	}
809 
810 	scsipi_wait_drain(periph);
811 
812 	scsipi_adapter_delref(adapt);
813 	periph->periph_flags &= ~PERIPH_OPEN;
814 
815 	return (error);
816 }
817 
818 /*
819  * Start a new mount session.
820  * Copy in all the default parameters from the selected device mode.
821  * and try guess any that seem to be defaulted.
822  */
823 static int
824 st_mount_tape(dev_t dev, int flags)
825 {
826 	int unit;
827 	u_int dsty;
828 	struct st_softc *st;
829 	struct scsipi_periph *periph;
830 	int error = 0;
831 
832 	unit = STUNIT(dev);
833 	dsty = STDSTY(dev);
834 	st = st_cd.cd_devs[unit];
835 	periph = st->sc_periph;
836 
837 	if (st->flags & ST_MOUNTED)
838 		return (0);
839 
840 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
841 	st->flags |= ST_NEW_MOUNT;
842 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
843 	/*
844 	 * If the media is new, then make sure we give it a chance to
845 	 * to do a 'load' instruction.  (We assume it is new.)
846 	 */
847 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
848 		return (error);
849 	/*
850 	 * Throw another dummy instruction to catch
851 	 * 'Unit attention' errors. Many drives give
852 	 * these after doing a Load instruction (with
853 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
854 	 */
855 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
856 
857 	/*
858 	 * Some devices can't tell you much until they have been
859 	 * asked to look at the media. This quirk does this.
860 	 */
861 	if (st->quirks & ST_Q_SENSE_HELP)
862 		if ((error = st_touch_tape(st)) != 0)
863 			return (error);
864 	/*
865 	 * Load the physical device parameters
866 	 * loads: blkmin, blkmax
867 	 */
868 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
869 		return (error);
870 	/*
871 	 * Load the media dependent parameters
872 	 * includes: media_blksize,media_density,numblks
873 	 * As we have a tape in, it should be reflected here.
874 	 * If not you may need the "quirk" above.
875 	 */
876 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
877 		return (error);
878 	/*
879 	 * If we have gained a permanent density from somewhere,
880 	 * then use it in preference to the one supplied by
881 	 * default by the driver.
882 	 */
883 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
884 		st->density = st->modes[dsty].density;
885 	else
886 		st->density = st->media_density;
887 	/*
888 	 * If we have gained a permanent blocksize
889 	 * then use it in preference to the one supplied by
890 	 * default by the driver.
891 	 */
892 	st->flags &= ~ST_FIXEDBLOCKS;
893 	if (st->modeflags[dsty] &
894 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
895 		st->blksize = st->modes[dsty].blksize;
896 		if (st->blksize)
897 			st->flags |= ST_FIXEDBLOCKS;
898 	} else {
899 		if ((error = st_decide_mode(st, FALSE)) != 0)
900 			return (error);
901 	}
902 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
903 		/* ATAPI will return ENODEV for this, and this may be OK */
904 		if (error != ENODEV) {
905 			printf("%s: cannot set selected mode\n",
906 			    st->sc_dev.dv_xname);
907 			return (error);
908 		}
909 	}
910 	st->flags &= ~ST_NEW_MOUNT;
911 	st->flags |= ST_MOUNTED;
912 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
913 	st->blkno = st->fileno = (daddr_t) 0;
914 	return (0);
915 }
916 
917 /*
918  * End the present mount session.
919  * Rewind, and optionally eject the tape.
920  * Reset various flags to indicate that all new
921  * operations require another mount operation
922  */
923 static void
924 st_unmount(struct st_softc *st, boolean eject)
925 {
926 	struct scsipi_periph *periph = st->sc_periph;
927 	int nmarks;
928 
929 	if ((st->flags & ST_MOUNTED) == 0)
930 		return;
931 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
932 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
933 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
934 
935 	/*
936 	 * Section 9.3.3 of the SCSI specs states that a device shall return
937 	 * the density value specified in the last succesfull MODE SELECT
938 	 * after an unload operation, in case it is not able to
939 	 * automatically determine the density of the new medium.
940 	 *
941 	 * So we instruct the device to use the default density, which will
942 	 * prevent the use of stale density values (in particular,
943 	 * in st_touch_tape().
944 	 */
945 	st->density = 0;
946 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
947 		printf("%s: WARNING: cannot revert to default density\n",
948 			st->sc_dev.dv_xname);
949 	}
950 
951 	if (eject) {
952 		if (!(st->quirks & ST_Q_NOPREVENT)) {
953 			scsipi_prevent(periph, SPAMR_ALLOW,
954 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
955 			    XS_CTL_IGNORE_NOT_READY);
956 		}
957 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
958 		st->blkno = st->fileno = (daddr_t) -1;
959 	} else {
960 		st->blkno = st->fileno = (daddr_t) 0;
961 	}
962 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
963 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
964 }
965 
966 /*
967  * Given all we know about the device, media, mode, 'quirks' and
968  * initial operation, make a decision as to how we should be set
969  * to run (regarding blocking and EOD marks)
970  */
971 int
972 st_decide_mode(struct st_softc *st, boolean first_read)
973 {
974 
975 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
976 
977 	/*
978 	 * If the drive can only handle fixed-length blocks and only at
979 	 * one size, perhaps we should just do that.
980 	 */
981 	if (st->blkmin && (st->blkmin == st->blkmax)) {
982 		st->flags |= ST_FIXEDBLOCKS;
983 		st->blksize = st->blkmin;
984 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
985 		    ("blkmin == blkmax of %d\n", st->blkmin));
986 		goto done;
987 	}
988 	/*
989 	 * If the tape density mandates (or even suggests) use of fixed
990 	 * or variable-length blocks, comply.
991 	 */
992 	switch (st->density) {
993 	case HALFINCH_800:
994 	case HALFINCH_1600:
995 	case HALFINCH_6250:
996 	case DDS:
997 		st->flags &= ~ST_FIXEDBLOCKS;
998 		st->blksize = 0;
999 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1000 		    ("density specified variable\n"));
1001 		goto done;
1002 	case QIC_11:
1003 	case QIC_24:
1004 	case QIC_120:
1005 	case QIC_150:
1006 	case QIC_525:
1007 	case QIC_1320:
1008 	case QIC_3095:
1009 	case QIC_3220:
1010 		st->flags |= ST_FIXEDBLOCKS;
1011 		if (st->media_blksize > 0)
1012 			st->blksize = st->media_blksize;
1013 		else
1014 			st->blksize = DEF_FIXED_BSIZE;
1015 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1016 		    ("density specified fixed\n"));
1017 		goto done;
1018 	}
1019 	/*
1020 	 * If we're about to read the tape, perhaps we should choose
1021 	 * fixed or variable-length blocks and block size according to
1022 	 * what the drive found on the tape.
1023 	 */
1024 	if (first_read &&
1025 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1026 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1027 	    (st->media_blksize == 1024))) {
1028 		if (st->media_blksize > 0)
1029 			st->flags |= ST_FIXEDBLOCKS;
1030 		else
1031 			st->flags &= ~ST_FIXEDBLOCKS;
1032 		st->blksize = st->media_blksize;
1033 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1034 		    ("Used media_blksize of %d\n", st->media_blksize));
1035 		goto done;
1036 	}
1037 	/*
1038 	 * We're getting no hints from any direction.  Choose variable-
1039 	 * length blocks arbitrarily.
1040 	 */
1041 	st->flags &= ~ST_FIXEDBLOCKS;
1042 	st->blksize = 0;
1043 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1044 	    ("Give up and default to variable mode\n"));
1045 
1046 done:
1047 	/*
1048 	 * Decide whether or not to write two file marks to signify end-
1049 	 * of-data.  Make the decision as a function of density.  If
1050 	 * the decision is not to use a second file mark, the SCSI BLANK
1051 	 * CHECK condition code will be recognized as end-of-data when
1052 	 * first read.
1053 	 * (I think this should be a by-product of fixed/variable..julian)
1054 	 */
1055 	switch (st->density) {
1056 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1057 	case QIC_11:
1058 	case QIC_24:
1059 	case QIC_120:
1060 	case QIC_150:
1061 	case QIC_525:
1062 	case QIC_1320:
1063 	case QIC_3095:
1064 	case QIC_3220:
1065 		st->flags &= ~ST_2FM_AT_EOD;
1066 		break;
1067 	default:
1068 		st->flags |= ST_2FM_AT_EOD;
1069 	}
1070 	return (0);
1071 }
1072 
1073 /*
1074  * Actually translate the requested transfer into
1075  * one the physical driver can understand
1076  * The transfer is described by a buf and will include
1077  * only one physical transfer.
1078  */
1079 static void
1080 ststrategy(struct buf *bp)
1081 {
1082 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1083 	int s;
1084 
1085 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1086 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
1087 	/*
1088 	 * If it's a null transfer, return immediatly
1089 	 */
1090 	if (bp->b_bcount == 0)
1091 		goto done;
1092 
1093 	/* If offset is negative, error */
1094 	if (bp->b_blkno < 0) {
1095 		bp->b_error = EINVAL;
1096 		goto bad;
1097 	}
1098 
1099 	/*
1100 	 * Odd sized request on fixed drives are verboten
1101 	 */
1102 	if (st->flags & ST_FIXEDBLOCKS) {
1103 		if (bp->b_bcount % st->blksize) {
1104 			printf("%s: bad request, must be multiple of %d\n",
1105 			    st->sc_dev.dv_xname, st->blksize);
1106 			bp->b_error = EIO;
1107 			goto bad;
1108 		}
1109 	}
1110 	/*
1111 	 * as are out-of-range requests on variable drives.
1112 	 */
1113 	else if (bp->b_bcount < st->blkmin ||
1114 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1115 		printf("%s: bad request, must be between %d and %d\n",
1116 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1117 		bp->b_error = EIO;
1118 		goto bad;
1119 	}
1120 	s = splbio();
1121 
1122 	/*
1123 	 * Place it in the queue of activities for this tape
1124 	 * at the end (a bit silly because we only have on user..
1125 	 * (but it could fork()))
1126 	 */
1127 	BUFQ_PUT(st->buf_queue, bp);
1128 
1129 	/*
1130 	 * Tell the device to get going on the transfer if it's
1131 	 * not doing anything, otherwise just wait for completion
1132 	 * (All a bit silly if we're only allowing 1 open but..)
1133 	 */
1134 	ststart(st->sc_periph);
1135 
1136 	splx(s);
1137 	return;
1138 bad:
1139 	bp->b_flags |= B_ERROR;
1140 done:
1141 	/*
1142 	 * Correctly set the buf to indicate a completed xfer
1143 	 */
1144 	bp->b_resid = bp->b_bcount;
1145 	biodone(bp);
1146 	return;
1147 }
1148 
1149 /*
1150  * ststart looks to see if there is a buf waiting for the device
1151  * and that the device is not already busy. If both are true,
1152  * It dequeues the buf and creates a scsi command to perform the
1153  * transfer required. The transfer request will call scsipi_done
1154  * on completion, which will in turn call this routine again
1155  * so that the next queued transfer is performed.
1156  * The bufs are queued by the strategy routine (ststrategy)
1157  *
1158  * This routine is also called after other non-queued requests
1159  * have been made of the scsi driver, to ensure that the queue
1160  * continues to be drained.
1161  * ststart() is called at splbio
1162  */
1163 static void
1164 ststart(struct scsipi_periph *periph)
1165 {
1166 	struct st_softc *st = (void *)periph->periph_dev;
1167 	struct buf *bp;
1168 	struct scsi_rw_tape cmd;
1169 	struct scsipi_xfer *xs;
1170 	int flags, error;
1171 
1172 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1173 	/*
1174 	 * See if there is a buf to do and we are not already
1175 	 * doing one
1176 	 */
1177 	while (periph->periph_active < periph->periph_openings) {
1178 		/* if a special awaits, let it proceed first */
1179 		if (periph->periph_flags & PERIPH_WAITING) {
1180 			periph->periph_flags &= ~PERIPH_WAITING;
1181 			wakeup((caddr_t)periph);
1182 			return;
1183 		}
1184 
1185 		/*
1186 		 * If the device has been unmounted by the user
1187 		 * then throw away all requests until done.
1188 		 */
1189 		if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
1190 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
1191 			if ((bp = BUFQ_GET(st->buf_queue)) != NULL) {
1192 				/* make sure that one implies the other.. */
1193 				periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1194 				bp->b_flags |= B_ERROR;
1195 				bp->b_error = EIO;
1196 				bp->b_resid = bp->b_bcount;
1197 				biodone(bp);
1198 				continue;
1199 			} else {
1200 				return;
1201 			}
1202 		}
1203 
1204 		if ((bp = BUFQ_PEEK(st->buf_queue)) == NULL)
1205 			return;
1206 
1207 		iostat_busy(st->stats);
1208 
1209 		/*
1210 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1211 		 */
1212 		if (st->flags & ST_FIXEDBLOCKS) {
1213 			/*
1214 			 * If we are at a filemark but have not reported it yet
1215 			 * then we should report it now
1216 			 */
1217 			if (st->flags & ST_AT_FILEMARK) {
1218 				if ((bp->b_flags & B_READ) == B_WRITE) {
1219 					/*
1220 					 * Handling of ST_AT_FILEMARK in
1221 					 * st_space will fill in the right file
1222 					 * mark count.
1223 					 * Back up over filemark
1224 					 */
1225 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1226 						BUFQ_GET(st->buf_queue);
1227 						bp->b_flags |= B_ERROR;
1228 						bp->b_error = EIO;
1229 						biodone(bp);
1230 						continue;
1231 					}
1232 				} else {
1233 					BUFQ_GET(st->buf_queue);
1234 					bp->b_resid = bp->b_bcount;
1235 					bp->b_error = 0;
1236 					bp->b_flags &= ~B_ERROR;
1237 					st->flags &= ~ST_AT_FILEMARK;
1238 					biodone(bp);
1239 					continue;	/* seek more work */
1240 				}
1241 			}
1242 		}
1243 		/*
1244 		 * If we are at EOM but have not reported it
1245 		 * yet then we should report it now.
1246 		 */
1247 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1248 			BUFQ_GET(st->buf_queue);
1249 			bp->b_resid = bp->b_bcount;
1250 			if (st->flags & ST_EIO_PENDING) {
1251 				bp->b_error = EIO;
1252 				bp->b_flags |= B_ERROR;
1253 			}
1254 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1255 			biodone(bp);
1256 			continue;	/* seek more work */
1257 		}
1258 
1259 		/*
1260 		 * Fill out the scsi command
1261 		 */
1262 		memset(&cmd, 0, sizeof(cmd));
1263 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1264 		if ((bp->b_flags & B_READ) == B_WRITE) {
1265 			cmd.opcode = WRITE;
1266 			st->flags &= ~ST_FM_WRITTEN;
1267 			flags |= XS_CTL_DATA_OUT;
1268 		} else {
1269 			cmd.opcode = READ;
1270 			flags |= XS_CTL_DATA_IN;
1271 		}
1272 
1273 		/*
1274 		 * Handle "fixed-block-mode" tape drives by using the
1275 		 * block count instead of the length.
1276 		 */
1277 		if (st->flags & ST_FIXEDBLOCKS) {
1278 			cmd.byte2 |= SRW_FIXED;
1279 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1280 		} else
1281 			_lto3b(bp->b_bcount, cmd.len);
1282 
1283 		/*
1284 		 * Clear 'position updated' indicator
1285 		 */
1286 		st->flags &= ~ST_POSUPDATED;
1287 
1288 		/*
1289 		 * go ask the adapter to do all this for us
1290 		 */
1291 		xs = scsipi_make_xs(periph,
1292 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1293 		    (u_char *)bp->b_data, bp->b_bcount,
1294 		    0, ST_IO_TIME, bp, flags);
1295 		if (__predict_false(xs == NULL)) {
1296 			/*
1297 			 * out of memory. Keep this buffer in the queue, and
1298 			 * retry later.
1299 			 */
1300 			callout_reset(&st->sc_callout, hz / 2, strestart,
1301 			    periph);
1302 			return;
1303 		}
1304 		/*
1305 		 * need to dequeue the buffer before queuing the command,
1306 		 * because cdstart may be called recursively from the
1307 		 * HBA driver
1308 		 */
1309 #ifdef DIAGNOSTIC
1310 		if (BUFQ_GET(st->buf_queue) != bp)
1311 			panic("ststart(): dequeued wrong buf");
1312 #else
1313 		BUFQ_GET(st->buf_queue);
1314 #endif
1315 		error = scsipi_execute_xs(xs);
1316 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
1317 		KASSERT(error == 0);
1318 	} /* go back and see if we can cram more work in.. */
1319 }
1320 
1321 static void
1322 strestart(void *v)
1323 {
1324 	int s = splbio();
1325 	ststart((struct scsipi_periph *)v);
1326 	splx(s);
1327 }
1328 
1329 
1330 static void
1331 stdone(struct scsipi_xfer *xs, int error)
1332 {
1333 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1334 	struct buf *bp = xs->bp;
1335 
1336 	if (bp) {
1337 		bp->b_error = error;
1338 		bp->b_resid = xs->resid;
1339 		if (error)
1340 			bp->b_flags |= B_ERROR;
1341 
1342 		if ((bp->b_flags & B_READ) == B_WRITE)
1343 			st->flags |= ST_WRITTEN;
1344 		else
1345 			st->flags &= ~ST_WRITTEN;
1346 
1347 		iostat_unbusy(st->stats, bp->b_bcount,
1348 			     ((bp->b_flags & B_READ) == B_READ));
1349 
1350 #if NRND > 0
1351 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
1352 #endif
1353 
1354 		if ((st->flags & ST_POSUPDATED) == 0) {
1355 			if (error) {
1356 				st->fileno = st->blkno = -1;
1357 			} else if (st->blkno != -1) {
1358 				if (st->flags & ST_FIXEDBLOCKS)
1359 					st->blkno +=
1360 					    (bp->b_bcount / st->blksize);
1361 				else
1362 					st->blkno++;
1363 			}
1364 		}
1365 
1366 		biodone(bp);
1367 	}
1368 }
1369 
1370 static int
1371 stread(dev_t dev, struct uio *uio, int iomode)
1372 {
1373 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1374 
1375 	return (physio(ststrategy, NULL, dev, B_READ,
1376 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1377 }
1378 
1379 static int
1380 stwrite(dev_t dev, struct uio *uio, int iomode)
1381 {
1382 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1383 
1384 	return (physio(ststrategy, NULL, dev, B_WRITE,
1385 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1386 }
1387 
1388 /*
1389  * Perform special action on behalf of the user;
1390  * knows about the internals of this device
1391  */
1392 static int
1393 stioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct lwp *l)
1394 {
1395 	int error = 0;
1396 	int unit;
1397 	int number, nmarks, dsty;
1398 	int flags;
1399 	struct st_softc *st;
1400 	int hold_blksize;
1401 	u_int8_t hold_density;
1402 	struct mtop *mt = (struct mtop *) arg;
1403 
1404 	/*
1405 	 * Find the device that the user is talking about
1406 	 */
1407 	flags = 0;		/* give error messages, act on errors etc. */
1408 	unit = STUNIT(dev);
1409 	dsty = STDSTY(dev);
1410 	st = st_cd.cd_devs[unit];
1411 	hold_blksize = st->blksize;
1412 	hold_density = st->density;
1413 
1414 	switch ((u_int) cmd) {
1415 
1416 	case MTIOCGET: {
1417 		struct mtget *g = (struct mtget *) arg;
1418 		/*
1419 		 * (to get the current state of READONLY)
1420 		 */
1421 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1422 		if (error) {
1423 			/*
1424 			 * Ignore the error if in control mode;
1425 			 * this is mandated by st(4).
1426 			 */
1427 			if (STMODE(dev) != CTRL_MODE)
1428 				break;
1429 			error = 0;
1430 		}
1431 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1432 		memset(g, 0, sizeof(struct mtget));
1433 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1434 		g->mt_blksiz = st->blksize;
1435 		g->mt_density = st->density;
1436 		g->mt_mblksiz[0] = st->modes[0].blksize;
1437 		g->mt_mblksiz[1] = st->modes[1].blksize;
1438 		g->mt_mblksiz[2] = st->modes[2].blksize;
1439 		g->mt_mblksiz[3] = st->modes[3].blksize;
1440 		g->mt_mdensity[0] = st->modes[0].density;
1441 		g->mt_mdensity[1] = st->modes[1].density;
1442 		g->mt_mdensity[2] = st->modes[2].density;
1443 		g->mt_mdensity[3] = st->modes[3].density;
1444 		g->mt_fileno = st->fileno;
1445 		g->mt_blkno = st->blkno;
1446 		if (st->flags & ST_READONLY)
1447 			g->mt_dsreg |= MT_DS_RDONLY;
1448 		if (st->flags & ST_MOUNTED)
1449 			g->mt_dsreg |= MT_DS_MOUNTED;
1450 		g->mt_resid = st->mt_resid;
1451 		g->mt_erreg = st->mt_erreg;
1452 		/*
1453 		 * clear latched errors.
1454 		 */
1455 		st->mt_resid = 0;
1456 		st->mt_erreg = 0;
1457 		st->asc = 0;
1458 		st->ascq = 0;
1459 		break;
1460 	}
1461 	case MTIOCTOP: {
1462 
1463 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1464 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1465 			mt->mt_count));
1466 
1467 		/* compat: in U*x it is a short */
1468 		number = mt->mt_count;
1469 		switch ((short) (mt->mt_op)) {
1470 		case MTWEOF:	/* write an end-of-file record */
1471 			error = st_write_filemarks(st, number, flags);
1472 			break;
1473 		case MTBSF:	/* backward space file */
1474 			number = -number;
1475 		case MTFSF:	/* forward space file */
1476 			error = st_check_eod(st, FALSE, &nmarks, flags);
1477 			if (!error)
1478 				error = st_space(st, number - nmarks,
1479 				    SP_FILEMARKS, flags);
1480 			break;
1481 		case MTBSR:	/* backward space record */
1482 			number = -number;
1483 		case MTFSR:	/* forward space record */
1484 			error = st_check_eod(st, TRUE, &nmarks, flags);
1485 			if (!error)
1486 				error = st_space(st, number, SP_BLKS, flags);
1487 			break;
1488 		case MTREW:	/* rewind */
1489 			error = st_rewind(st, 0, flags);
1490 			break;
1491 		case MTOFFL:	/* rewind and put the drive offline */
1492 			st_unmount(st, EJECT);
1493 			break;
1494 		case MTNOP:	/* no operation, sets status only */
1495 			break;
1496 		case MTRETEN:	/* retension the tape */
1497 			error = st_load(st, LD_RETENSION, flags);
1498 			if (!error)
1499 				error = st_load(st, LD_LOAD, flags);
1500 			break;
1501 		case MTEOM:	/* forward space to end of media */
1502 			error = st_check_eod(st, FALSE, &nmarks, flags);
1503 			if (!error)
1504 				error = st_space(st, 1, SP_EOM, flags);
1505 			break;
1506 		case MTCACHE:	/* enable controller cache */
1507 			st->flags &= ~ST_DONTBUFFER;
1508 			goto try_new_value;
1509 		case MTNOCACHE:	/* disable controller cache */
1510 			st->flags |= ST_DONTBUFFER;
1511 			goto try_new_value;
1512 		case MTERASE:	/* erase volume */
1513 			error = st_erase(st, number, flags);
1514 			break;
1515 		case MTSETBSIZ:	/* Set block size for device */
1516 #ifdef	NOTYET
1517 			if (!(st->flags & ST_NEW_MOUNT)) {
1518 				uprintf("re-mount tape before changing blocksize");
1519 				error = EINVAL;
1520 				break;
1521 			}
1522 #endif
1523 			if (number == 0)
1524 				st->flags &= ~ST_FIXEDBLOCKS;
1525 			else {
1526 				if ((st->blkmin || st->blkmax) &&
1527 				    (number < st->blkmin ||
1528 				    number > st->blkmax)) {
1529 					error = EINVAL;
1530 					break;
1531 				}
1532 				st->flags |= ST_FIXEDBLOCKS;
1533 			}
1534 			st->blksize = number;
1535 			st->flags |= ST_BLOCK_SET;	/*XXX */
1536 			goto try_new_value;
1537 
1538 		case MTSETDNSTY:	/* Set density for device and mode */
1539 			/*
1540 			 * Any number >= 0 and <= 0xff is legal. Numbers
1541 			 * above 0x80 are 'vendor unique'.
1542 			 */
1543 			if (number < 0 || number > 255) {
1544 				error = EINVAL;
1545 				break;
1546 			} else
1547 				st->density = number;
1548 			goto try_new_value;
1549 
1550 		case MTCMPRESS:
1551 			error = st->ops(st, (number == 0) ?
1552 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1553 			    XS_CTL_SILENT);
1554 			break;
1555 
1556 		case MTEWARN:
1557 			if (number)
1558 				st->flags |= ST_EARLYWARN;
1559 			else
1560 				st->flags &= ~ST_EARLYWARN;
1561 			break;
1562 
1563 		default:
1564 			error = EINVAL;
1565 		}
1566 		break;
1567 	}
1568 	case MTIOCIEOT:
1569 	case MTIOCEEOT:
1570 		break;
1571 
1572 	case MTIOCRDSPOS:
1573 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1574 		break;
1575 
1576 	case MTIOCRDHPOS:
1577 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1578 		break;
1579 
1580 	case MTIOCSLOCATE:
1581 		error = st_setpos(st, 0, (u_int32_t *) arg);
1582 		break;
1583 
1584 	case MTIOCHLOCATE:
1585 		error = st_setpos(st, 1, (u_int32_t *) arg);
1586 		break;
1587 
1588 
1589 	default:
1590 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1591 					flag, l);
1592 		break;
1593 	}
1594 	return (error);
1595 /*-----------------------------*/
1596 try_new_value:
1597 	/*
1598 	 * Check that the mode being asked for is aggreeable to the
1599 	 * drive. If not, put it back the way it was.
1600 	 *
1601 	 * If in control mode, we can make (persistent) mode changes
1602 	 * even if no medium is loaded (see st(4)).
1603 	 */
1604 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1605 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1606 		/* put it back as it was */
1607 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1608 		st->density = hold_density;
1609 		st->blksize = hold_blksize;
1610 		if (st->blksize)
1611 			st->flags |= ST_FIXEDBLOCKS;
1612 		else
1613 			st->flags &= ~ST_FIXEDBLOCKS;
1614 		return (error);
1615 	}
1616 	/*
1617 	 * As the drive liked it, if we are setting a new default,
1618 	 * set it into the structures as such.
1619 	 *
1620 	 * The means for deciding this are not finalised yet- but
1621 	 * if the device was opened in Control Mode, the values
1622 	 * are persistent now across mounts.
1623 	 */
1624 	if (STMODE(dev) == CTRL_MODE) {
1625 		switch ((short) (mt->mt_op)) {
1626 		case MTSETBSIZ:
1627 			st->modes[dsty].blksize = st->blksize;
1628 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1629 			break;
1630 		case MTSETDNSTY:
1631 			st->modes[dsty].density = st->density;
1632 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1633 			break;
1634 		}
1635 	}
1636 	return (0);
1637 }
1638 
1639 /*
1640  * Do a synchronous read.
1641  */
1642 static int
1643 st_read(struct st_softc *st, char *bf, int size, int flags)
1644 {
1645 	struct scsi_rw_tape cmd;
1646 
1647 	/*
1648 	 * If it's a null transfer, return immediatly
1649 	 */
1650 	if (size == 0)
1651 		return (0);
1652 	memset(&cmd, 0, sizeof(cmd));
1653 	cmd.opcode = READ;
1654 	if (st->flags & ST_FIXEDBLOCKS) {
1655 		cmd.byte2 |= SRW_FIXED;
1656 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1657 		    cmd.len);
1658 	} else
1659 		_lto3b(size, cmd.len);
1660 	return (scsipi_command(st->sc_periph,
1661 	    (void *)&cmd, sizeof(cmd), (void *)bf, size, 0, ST_IO_TIME, NULL,
1662 	    flags | XS_CTL_DATA_IN));
1663 }
1664 
1665 /*
1666  * issue an erase command
1667  */
1668 static int
1669 st_erase(struct st_softc *st, int full, int flags)
1670 {
1671 	int tmo;
1672 	struct scsi_erase cmd;
1673 
1674 	/*
1675 	 * Full erase means set LONG bit in erase command, which asks
1676 	 * the drive to erase the entire unit.  Without this bit, we're
1677 	 * asking the drive to write an erase gap.
1678 	 */
1679 	memset(&cmd, 0, sizeof(cmd));
1680 	cmd.opcode = ERASE;
1681 	if (full) {
1682 		cmd.byte2 = SE_LONG;
1683 		tmo = ST_SPC_TIME;
1684 	} else {
1685 		tmo = ST_IO_TIME;
1686 	}
1687 
1688 	/*
1689 	 * XXX We always do this asynchronously, for now, unless the device
1690 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1691 	 * want to (eventually) to it synchronously?
1692 	 */
1693 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1694 		cmd.byte2 |= SE_IMMED;
1695 
1696 	return (scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1697 	    ST_RETRIES, tmo, NULL, flags));
1698 }
1699 
1700 /*
1701  * skip N blocks/filemarks/seq filemarks/eom
1702  */
1703 static int
1704 st_space(struct st_softc *st, int number, u_int what, int flags)
1705 {
1706 	struct scsi_space cmd;
1707 	int error;
1708 
1709 	switch (what) {
1710 	case SP_BLKS:
1711 		if (st->flags & ST_PER_ACTION) {
1712 			if (number > 0) {
1713 				st->flags &= ~ST_PER_ACTION;
1714 				return (EIO);
1715 			} else if (number < 0) {
1716 				if (st->flags & ST_AT_FILEMARK) {
1717 					/*
1718 					 * Handling of ST_AT_FILEMARK
1719 					 * in st_space will fill in the
1720 					 * right file mark count.
1721 					 */
1722 					error = st_space(st, 0, SP_FILEMARKS,
1723 					    flags);
1724 					if (error)
1725 						return (error);
1726 				}
1727 				if (st->flags & ST_BLANK_READ) {
1728 					st->flags &= ~ST_BLANK_READ;
1729 					return (EIO);
1730 				}
1731 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1732 			}
1733 		}
1734 		break;
1735 	case SP_FILEMARKS:
1736 		if (st->flags & ST_EIO_PENDING) {
1737 			if (number > 0) {
1738 				/* pretend we just discovered the error */
1739 				st->flags &= ~ST_EIO_PENDING;
1740 				return (EIO);
1741 			} else if (number < 0) {
1742 				/* back away from the error */
1743 				st->flags &= ~ST_EIO_PENDING;
1744 			}
1745 		}
1746 		if (st->flags & ST_AT_FILEMARK) {
1747 			st->flags &= ~ST_AT_FILEMARK;
1748 			number--;
1749 		}
1750 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1751 			/* back away from unwritten tape */
1752 			st->flags &= ~ST_BLANK_READ;
1753 			number++;	/* XXX dubious */
1754 		}
1755 		break;
1756 	case SP_EOM:
1757 		if (st->flags & ST_EOM_PENDING) {
1758 			/* we're already there */
1759 			st->flags &= ~ST_EOM_PENDING;
1760 			return (0);
1761 		}
1762 		if (st->flags & ST_EIO_PENDING) {
1763 			/* pretend we just discovered the error */
1764 			st->flags &= ~ST_EIO_PENDING;
1765 			return (EIO);
1766 		}
1767 		if (st->flags & ST_AT_FILEMARK)
1768 			st->flags &= ~ST_AT_FILEMARK;
1769 		break;
1770 	}
1771 	if (number == 0)
1772 		return (0);
1773 
1774 	memset(&cmd, 0, sizeof(cmd));
1775 	cmd.opcode = SPACE;
1776 	cmd.byte2 = what;
1777 	_lto3b(number, cmd.number);
1778 
1779 	st->flags &= ~ST_POSUPDATED;
1780 	st->last_ctl_resid = 0;
1781 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1782 	    0, ST_SPC_TIME, NULL, flags);
1783 
1784 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1785 		number = number - st->last_ctl_resid;
1786 		if (what == SP_BLKS) {
1787 			if (st->blkno != -1) {
1788 				st->blkno += number;
1789 			}
1790 		} else if (what == SP_FILEMARKS) {
1791 			if (st->fileno != -1) {
1792 				st->fileno += number;
1793 				if (number > 0) {
1794 					st->blkno = 0;
1795 				} else if (number < 0) {
1796 					st->blkno = -1;
1797 				}
1798 			}
1799 		} else if (what == SP_EOM) {
1800 			/*
1801 			 * This loses us relative position.
1802 			 */
1803 			st->fileno = st->blkno = -1;
1804 		}
1805 	}
1806 	return (error);
1807 }
1808 
1809 /*
1810  * write N filemarks
1811  */
1812 static int
1813 st_write_filemarks(struct st_softc *st, int number, int flags)
1814 {
1815 	int error;
1816 	struct scsi_write_filemarks cmd;
1817 
1818 	/*
1819 	 * It's hard to write a negative number of file marks.
1820 	 * Don't try.
1821 	 */
1822 	if (number < 0)
1823 		return (EINVAL);
1824 	switch (number) {
1825 	case 0:		/* really a command to sync the drive's buffers */
1826 		break;
1827 	case 1:
1828 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1829 			st->flags &= ~ST_WRITTEN;
1830 		else
1831 			st->flags |= ST_FM_WRITTEN;
1832 		st->flags &= ~ST_PER_ACTION;
1833 		break;
1834 	default:
1835 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1836 	}
1837 
1838 	memset(&cmd, 0, sizeof(cmd));
1839 	cmd.opcode = WRITE_FILEMARKS;
1840 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1841 		cmd.byte2 = SR_IMMED;
1842 	/*
1843 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1844 	 * WRITE_FILEMARKS is still used to flush the buffer
1845 	 */
1846 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1847 		_lto3b(number, cmd.number);
1848 
1849 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1850 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1851 	    0, ST_IO_TIME * 4, NULL, flags);
1852 	if (error == 0 && st->fileno != -1) {
1853 		st->fileno += number;
1854 	}
1855 	return (error);
1856 }
1857 
1858 /*
1859  * Make sure the right number of file marks is on tape if the
1860  * tape has been written.  If the position argument is true,
1861  * leave the tape positioned where it was originally.
1862  *
1863  * nmarks returns the number of marks to skip (or, if position
1864  * true, which were skipped) to get back original position.
1865  */
1866 static int
1867 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
1868 {
1869 	int error;
1870 
1871 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1872 	default:
1873 		*nmarks = 0;
1874 		return (0);
1875 	case ST_WRITTEN:
1876 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1877 		*nmarks = 1;
1878 		break;
1879 	case ST_WRITTEN | ST_2FM_AT_EOD:
1880 		*nmarks = 2;
1881 	}
1882 	error = st_write_filemarks(st, *nmarks, flags);
1883 	if (position && !error)
1884 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1885 	return (error);
1886 }
1887 
1888 /*
1889  * load/unload/retension
1890  */
1891 static int
1892 st_load(struct st_softc *st, u_int type, int flags)
1893 {
1894 	int error;
1895 	struct scsi_load cmd;
1896 
1897 	if (type != LD_LOAD) {
1898 		int nmarks;
1899 
1900 		error = st_check_eod(st, FALSE, &nmarks, flags);
1901 		if (error) {
1902 			printf("%s: failed to write closing filemarks at "
1903 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1904 			return (error);
1905 		}
1906 	}
1907 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1908 		if (type == LD_LOAD) {
1909 			/*
1910 			 * If we ignore loads, at least we should try a rewind.
1911 			 */
1912 			return st_rewind(st, 0, flags);
1913 		}
1914 		/* otherwise, we should do what's asked of us */
1915 	}
1916 
1917 	memset(&cmd, 0, sizeof(cmd));
1918 	cmd.opcode = LOAD;
1919 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1920 		cmd.byte2 = SR_IMMED;
1921 	cmd.how = type;
1922 
1923 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1924 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
1925 	if (error) {
1926 		printf("%s: error %d in st_load (op %d)\n",
1927 		    st->sc_dev.dv_xname, error, type);
1928 	}
1929 	return (error);
1930 }
1931 
1932 /*
1933  *  Rewind the device
1934  */
1935 static int
1936 st_rewind(struct st_softc *st, u_int immediate, int flags)
1937 {
1938 	struct scsi_rewind cmd;
1939 	int error;
1940 	int nmarks;
1941 
1942 	error = st_check_eod(st, FALSE, &nmarks, flags);
1943 	if (error) {
1944 		printf("%s: failed to write closing filemarks at "
1945 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1946 		return (error);
1947 	}
1948 	st->flags &= ~ST_PER_ACTION;
1949 
1950 	/*
1951 	 * ATAPI tapes always need immediate to be set
1952 	 */
1953 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1954 		immediate = SR_IMMED;
1955 
1956 	memset(&cmd, 0, sizeof(cmd));
1957 	cmd.opcode = REWIND;
1958 	cmd.byte2 = immediate;
1959 
1960 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1961 	    ST_RETRIES, immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
1962 	if (error) {
1963 		printf("%s: error %d trying to rewind\n",
1964 		    st->sc_dev.dv_xname, error);
1965 		/* lost position */
1966 		st->fileno = st->blkno = -1;
1967 	} else {
1968 		st->fileno = st->blkno = 0;
1969 	}
1970 	return (error);
1971 }
1972 
1973 static int
1974 st_rdpos(struct st_softc *st, int hard, u_int32_t *blkptr)
1975 {
1976 	int error;
1977 	u_int8_t posdata[20];
1978 	struct scsi_tape_read_position cmd;
1979 
1980 	/*
1981 	 * We try and flush any buffered writes here if we were writing
1982 	 * and we're trying to get hardware block position. It eats
1983 	 * up performance substantially, but I'm wary of drive firmware.
1984 	 *
1985 	 * I think that *logical* block position is probably okay-
1986 	 * but hardware block position might have to wait for data
1987 	 * to hit media to be valid. Caveat Emptor.
1988 	 */
1989 
1990 	if (hard && (st->flags & ST_WRITTEN)) {
1991 		/*
1992 		 * First flush any pending writes...
1993 		 */
1994 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
1995 		/*
1996 		 * The latter case is for 'write protected' tapes
1997 		 * which are too stupid to recognize a zero count
1998 		 * for writing filemarks as a no-op.
1999 		 */
2000 		if (error != 0 && error != EACCES && error != EROFS)
2001 			return (error);
2002 	}
2003 
2004 	memset(&cmd, 0, sizeof(cmd));
2005 	memset(&posdata, 0, sizeof(posdata));
2006 	cmd.opcode = READ_POSITION;
2007 	if (hard)
2008 		cmd.byte1 = 1;
2009 
2010 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
2011 	    (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
2012 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
2013 
2014 	if (error == 0) {
2015 #if	0
2016 		printf("posdata:");
2017 		for (hard = 0; hard < sizeof(posdata); hard++)
2018 			printf("%02x ", posdata[hard] & 0xff);
2019 		printf("\n");
2020 #endif
2021 		if (posdata[0] & 0x4)	/* Block Position Unknown */
2022 			error = EINVAL;
2023 		else
2024 			*blkptr = _4btol(&posdata[4]);
2025 	}
2026 	return (error);
2027 }
2028 
2029 static int
2030 st_setpos(struct st_softc *st, int hard, u_int32_t *blkptr)
2031 {
2032 	int error;
2033 	struct scsi_tape_locate cmd;
2034 
2035 	/*
2036 	 * We used to try and flush any buffered writes here.
2037 	 * Now we push this onto user applications to either
2038 	 * flush the pending writes themselves (via a zero count
2039 	 * WRITE FILEMARKS command) or they can trust their tape
2040 	 * drive to do this correctly for them.
2041 	 *
2042 	 * There are very ugly performance limitations otherwise.
2043 	 */
2044 
2045 	memset(&cmd, 0, sizeof(cmd));
2046 	cmd.opcode = LOCATE;
2047 	if (hard)
2048 		cmd.byte2 = 1 << 2;
2049 	_lto4b(*blkptr, cmd.blkaddr);
2050 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
2051 	    ST_RETRIES, ST_SPC_TIME, NULL, 0);
2052 	/*
2053 	 * Note file && block number position now unknown (if
2054 	 * these things ever start being maintained in this driver)
2055 	 */
2056 	st->fileno = st->blkno = -1;
2057 	return (error);
2058 }
2059 
2060 
2061 /*
2062  * Look at the returned sense and act on the error and determine
2063  * the unix error number to pass back..., 0 (== report no error),
2064  * -1 = retry the operation, -2 continue error processing.
2065  */
2066 static int
2067 st_interpret_sense(struct scsipi_xfer *xs)
2068 {
2069 	struct scsipi_periph *periph = xs->xs_periph;
2070 	struct scsi_sense_data *sense = &xs->sense.scsi_sense;
2071 	struct buf *bp = xs->bp;
2072 	struct st_softc *st = (void *)periph->periph_dev;
2073 	int retval = EJUSTRETURN;
2074 	int doprint = ((xs->xs_control & XS_CTL_SILENT) == 0);
2075 	u_int8_t key;
2076 	int32_t info;
2077 
2078 	/*
2079 	 * If it isn't a extended or extended/deferred error, let
2080 	 * the generic code handle it.
2081 	 */
2082 	if (SSD_RCODE(sense->response_code) != SSD_RCODE_CURRENT &&
2083 	    SSD_RCODE(sense->response_code) != SSD_RCODE_DEFERRED)
2084 		return (retval);
2085 
2086 	if (sense->response_code & SSD_RCODE_VALID)
2087 		info = _4btol(sense->info);
2088 	else
2089 		info = (st->flags & ST_FIXEDBLOCKS) ?
2090 		    xs->datalen / st->blksize : xs->datalen;
2091 	key = SSD_SENSE_KEY(sense->flags);
2092 	st->mt_erreg = key;
2093 	st->asc = sense->asc;
2094 	st->ascq = sense->ascq;
2095 	st->mt_resid = (short) info;
2096 
2097 	if (key == SKEY_NOT_READY && st->asc == 0x4 && st->ascq == 0x1) {
2098 		/* Not Ready, Logical Unit Is in Process Of Becoming Ready */
2099 		if (!callout_pending(&periph->periph_callout))
2100 			scsipi_periph_freeze(periph, 1);
2101 		callout_reset(&periph->periph_callout,
2102 		    hz, scsipi_periph_timed_thaw, periph);
2103 		return (ERESTART);
2104 	}
2105 
2106 	/*
2107 	 * If the device is not open yet, let generic handle
2108 	 */
2109 	if ((periph->periph_flags & PERIPH_OPEN) == 0) {
2110 		return (retval);
2111 	}
2112 
2113 	xs->resid = info;
2114 	if (st->flags & ST_FIXEDBLOCKS) {
2115 		if (bp) {
2116 			xs->resid *= st->blksize;
2117 			st->last_io_resid = xs->resid;
2118 		} else {
2119 			st->last_ctl_resid = xs->resid;
2120 		}
2121 		if (key == SKEY_VOLUME_OVERFLOW) {
2122 			st->flags |= ST_EIO_PENDING;
2123 			if (bp)
2124 				bp->b_resid = xs->resid;
2125 		} else if (sense->flags & SSD_EOM) {
2126 			if ((st->flags & ST_EARLYWARN) == 0)
2127 				st->flags |= ST_EIO_PENDING;
2128 			st->flags |= ST_EOM_PENDING;
2129 			if (bp) {
2130 #if 0
2131 				bp->b_resid = xs->resid;
2132 #else
2133 				/*
2134 				 * Grotesque as it seems, the few times
2135 				 * I've actually seen a non-zero resid,
2136 				 * the tape drive actually lied and had
2137 				 * written all the data!
2138 				 */
2139 				bp->b_resid = 0;
2140 #endif
2141 			}
2142 		}
2143 		if (sense->flags & SSD_FILEMARK) {
2144 			st->flags |= ST_AT_FILEMARK;
2145 			if (bp)
2146 				bp->b_resid = xs->resid;
2147 			if (st->fileno != (daddr_t) -1) {
2148 				st->fileno++;
2149 				st->blkno = 0;
2150 				st->flags |= ST_POSUPDATED;
2151 			}
2152 		}
2153 		if (sense->flags & SSD_ILI) {
2154 			st->flags |= ST_EIO_PENDING;
2155 			if (bp)
2156 				bp->b_resid = xs->resid;
2157 			if (sense->response_code & SSD_RCODE_VALID &&
2158 			    (xs->xs_control & XS_CTL_SILENT) == 0)
2159 				printf("%s: block wrong size, %d blocks "
2160 				    "residual\n", st->sc_dev.dv_xname, info);
2161 
2162 			/*
2163 			 * This quirk code helps the drive read
2164 			 * the first tape block, regardless of
2165 			 * format.  That is required for these
2166 			 * drives to return proper MODE SENSE
2167 			 * information.
2168 			 */
2169 			if ((st->quirks & ST_Q_SENSE_HELP) &&
2170 			    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
2171 				st->blksize -= 512;
2172 			else if ((st->flags & ST_POSUPDATED) == 0) {
2173 				if (st->blkno != (daddr_t) -1) {
2174 					st->blkno +=
2175 					    (xs->datalen / st->blksize);
2176 					st->flags |= ST_POSUPDATED;
2177 				}
2178 			}
2179 		}
2180 		/*
2181 		 * If data wanted and no data was transferred, do it immediately
2182 		 */
2183 		if (xs->datalen && xs->resid >= xs->datalen) {
2184 			if (st->flags & ST_EIO_PENDING)
2185 				return (EIO);
2186 			if (st->flags & ST_AT_FILEMARK) {
2187 				if (bp)
2188 					bp->b_resid = xs->resid;
2189 				return (0);
2190 			}
2191 		}
2192 	} else {		/* must be variable mode */
2193 		if (bp) {
2194 			st->last_io_resid = xs->resid;
2195 		} else {
2196 			st->last_ctl_resid = xs->resid;
2197 		}
2198 		if (sense->flags & SSD_EOM) {
2199 			/*
2200 			 * The current semantics of this
2201 			 * driver requires EOM detection
2202 			 * to return EIO unless early
2203 			 * warning detection is enabled
2204 			 * for variable mode (this is always
2205 			 * on for fixed block mode).
2206 			 */
2207 			if (st->flags & ST_EARLYWARN) {
2208 				st->flags |= ST_EOM_PENDING;
2209 				retval = 0;
2210 			} else {
2211 				retval = EIO;
2212 			}
2213 
2214 			/*
2215 			 * If it's an unadorned EOM detection,
2216 			 * suppress printing an error.
2217 			 */
2218 			if (key == SKEY_NO_SENSE) {
2219 				doprint = 0;
2220 			}
2221 		} else if (sense->flags & SSD_FILEMARK) {
2222 			retval = 0;
2223 			if (st->fileno != (daddr_t) -1) {
2224 				st->fileno++;
2225 				st->blkno = 0;
2226 				st->flags |= ST_POSUPDATED;
2227 			}
2228 		} else if (sense->flags & SSD_ILI) {
2229 			if (info < 0) {
2230 				/*
2231 				 * The tape record was bigger than the read
2232 				 * we issued.
2233 				 */
2234 				if ((xs->xs_control & XS_CTL_SILENT) == 0) {
2235 					printf("%s: %d-byte tape record too big"
2236 					    " for %d-byte user buffer\n",
2237 					    st->sc_dev.dv_xname,
2238 					    xs->datalen - info, xs->datalen);
2239 				}
2240 				retval = EIO;
2241 			} else {
2242 				retval = 0;
2243 				if (st->blkno != (daddr_t) -1) {
2244 					st->blkno++;
2245 					st->flags |= ST_POSUPDATED;
2246 				}
2247 			}
2248 		}
2249 		if (bp)
2250 			bp->b_resid = info;
2251 	}
2252 
2253 #ifndef SCSIPI_DEBUG
2254 	if (retval == 0 && key == SKEY_NO_SENSE)
2255 		doprint = 0;
2256 #endif
2257 	if (key == SKEY_BLANK_CHECK) {
2258 		/*
2259 		 * This quirk code helps the drive read the
2260 		 * first tape block, regardless of format.  That
2261 		 * is required for these drives to return proper
2262 		 * MODE SENSE information.
2263 		 */
2264 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2265 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
2266 			/* still starting */
2267 			st->blksize -= 512;
2268 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2269 			st->flags |= ST_BLANK_READ;
2270 			xs->resid = xs->datalen;
2271 			if (bp) {
2272 				bp->b_resid = xs->resid;
2273 				/* return an EOF */
2274 			}
2275 			retval = 0;
2276 			/* lost position */
2277 			st->fileno = st->blkno = -1;
2278 		}
2279 	}
2280 
2281 	/*
2282 	 * If generic sense processing will continue, we should not
2283 	 * print sense info here.
2284 	 */
2285 	if (retval == EJUSTRETURN)
2286 		doprint = 0;
2287 
2288 	if (doprint) {
2289 #ifdef	SCSIVERBOSE
2290 		scsipi_print_sense(xs, 0);
2291 #else
2292 		scsipi_printaddr(periph);
2293 		printf("Sense Key 0x%02x", key);
2294 		if ((sense->response_code & SSD_RCODE_VALID) != 0) {
2295 			switch (key) {
2296 			case SKEY_NOT_READY:
2297 			case SKEY_ILLEGAL_REQUEST:
2298 			case SKEY_UNIT_ATTENTION:
2299 			case SKEY_DATA_PROTECT:
2300 				break;
2301 			case SKEY_VOLUME_OVERFLOW:
2302 			case SKEY_BLANK_CHECK:
2303 				printf(", requested size: %d (decimal)", info);
2304 				break;
2305 			case SKEY_ABORTED_COMMAND:
2306 				if (xs->xs_retries)
2307 					printf(", retrying");
2308 				printf(", cmd 0x%x, info 0x%x",
2309 				    xs->cmd->opcode, info);
2310 				break;
2311 			default:
2312 				printf(", info = %d (decimal)", info);
2313 			}
2314 		}
2315 		if (sense->extra_len != 0) {
2316 			int n;
2317 			printf(", data =");
2318 			for (n = 0; n < sense->extra_len; n++)
2319 				printf(" %02x", sense->csi[n]);
2320 		}
2321 		printf("\n");
2322 #endif
2323 	}
2324 	return (retval);
2325 }
2326 
2327 /*
2328  * The quirk here is that the drive returns some value to st_mode_sense
2329  * incorrectly until the tape has actually passed by the head.
2330  *
2331  * The method is to set the drive to large fixed-block state (user-specified
2332  * density and 1024-byte blocks), then read and rewind to get it to sense the
2333  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2334  * work, as a last resort, try variable- length blocks.  The result will be
2335  * the ability to do an accurate st_mode_sense.
2336  *
2337  * We know we can do a rewind because we just did a load, which implies rewind.
2338  * Rewind seems preferable to space backward if we have a virgin tape.
2339  *
2340  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2341  * error processing, both part of st_interpret_sense.
2342  */
2343 static int
2344 st_touch_tape(struct st_softc *st)
2345 {
2346 	char *bf;
2347 	int readsize;
2348 	int error;
2349 
2350 	bf = malloc(1024, M_TEMP, M_NOWAIT);
2351 	if (bf == NULL)
2352 		return (ENOMEM);
2353 
2354 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
2355 		goto bad;
2356 
2357 	/*
2358 	 * If the block size is already known from the
2359 	 * sense data, use it. Else start probing at 1024.
2360 	 */
2361 	if (st->media_blksize > 0)
2362 		st->blksize = st->media_blksize;
2363 	else
2364 		st->blksize = 1024;
2365 
2366 	do {
2367 		switch (st->blksize) {
2368 		case 512:
2369 		case 1024:
2370 			readsize = st->blksize;
2371 			st->flags |= ST_FIXEDBLOCKS;
2372 			break;
2373 		default:
2374 			readsize = 1;
2375 			st->flags &= ~ST_FIXEDBLOCKS;
2376 		}
2377 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
2378 		    != 0) {
2379 			/*
2380 			 * The device did not agree with the proposed
2381 			 * block size. If we exhausted our options,
2382 			 * return failure, else try another.
2383 			 */
2384 			if (readsize == 1)
2385 				goto bad;
2386 			st->blksize -= 512;
2387 			continue;
2388 		}
2389 		st_read(st, bf, readsize, XS_CTL_SILENT);	/* XXX */
2390 		if ((error = st_rewind(st, 0, 0)) != 0) {
2391 bad:			free(bf, M_TEMP);
2392 			return (error);
2393 		}
2394 	} while (readsize != 1 && readsize > st->blksize);
2395 
2396 	free(bf, M_TEMP);
2397 	return (0);
2398 }
2399 
2400 static int
2401 stdump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
2402 {
2403 
2404 	/* Not implemented. */
2405 	return (ENXIO);
2406 }
2407