xref: /netbsd-src/sys/dev/scsipi/st.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: st.c,v 1.202 2007/10/11 16:42:52 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 1.202 2007/10/11 16:42:52 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 #ifndef		ST_MOUNT_DELAY
104 #define		ST_MOUNT_DELAY		0
105 #endif
106 
107 static dev_type_open(stopen);
108 static dev_type_close(stclose);
109 static dev_type_read(stread);
110 static dev_type_write(stwrite);
111 static dev_type_ioctl(stioctl);
112 static dev_type_strategy(ststrategy);
113 static dev_type_dump(stdump);
114 
115 const struct bdevsw st_bdevsw = {
116 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
117 };
118 
119 const struct cdevsw st_cdevsw = {
120 	stopen, stclose, stread, stwrite, stioctl,
121 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
122 };
123 
124 /*
125  * Define various devices that we know mis-behave in some way,
126  * and note how they are bad, so we can correct for them
127  */
128 
129 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
130 	{{T_SEQUENTIAL, T_REMOV,
131 	 "        ", "                ", "    "}, {0, 0, {
132 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
133 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
134 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
135 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
136 	}}},
137 	{{T_SEQUENTIAL, T_REMOV,
138 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
139 		{0, 0, 0},				/* minor 0-3 */
140 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
141 		{0, 0, QIC_150},			/* minor 8-11 */
142 		{0, 0, QIC_120}				/* minor 12-15 */
143 	}}},
144  	{{T_SEQUENTIAL, T_REMOV,
145  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
146 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
147 		{0, 0, QIC_525},			/* minor 4-7 */
148 		{0, 0, QIC_150},			/* minor 8-11 */
149 		{0, 0, QIC_120}				/* minor 12-15 */
150 	}}},
151 	{{T_SEQUENTIAL, T_REMOV,
152 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
153 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
154 		{0, 0, 0},				/* minor 4-7 */
155 		{0, 0, 0},				/* minor 8-11 */
156 		{0, 0, 0}				/* minor 12-15 */
157 	}}},
158 	/*
159 	 * lacking a manual for the 4200, it's not clear what the
160 	 * specific density codes should be- the device is a 2.5GB
161 	 * capable QIC drive, those density codes aren't readily
162 	 * availabel. The 'default' will just have to do.
163 	 */
164  	{{T_SEQUENTIAL, T_REMOV,
165  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
166 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
167 		{0, 0, QIC_525},			/* minor 4-7 */
168 		{0, 0, QIC_150},			/* minor 8-11 */
169 		{0, 0, QIC_120}				/* minor 12-15 */
170 	}}},
171 	/*
172 	 * At least -005 and -007 need this.  I'll assume they all do unless I
173 	 * hear otherwise.  - mycroft, 31MAR1994
174 	 */
175 	{{T_SEQUENTIAL, T_REMOV,
176 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
177 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
178 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
179 		{0, 0, QIC_150},			/* minor 8-11 */
180 		{0, 0, QIC_120}				/* minor 12-15 */
181 	}}},
182 	/*
183 	 * One user reports that this works for his tape drive.  It probably
184 	 * needs more work.  - mycroft, 09APR1994
185 	 */
186 	{{T_SEQUENTIAL, T_REMOV,
187 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
188 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
189 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
190 		{0, 0, QIC_150},			/* minor 8-11 */
191 		{0, 0, QIC_120}				/* minor 12-15 */
192 	}}},
193 	{{T_SEQUENTIAL, T_REMOV,
194 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
195 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
196 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
197 		{0, 0, QIC_150},			/* minor 8-11 */
198 		{0, 0, QIC_120}				/* minor 12-15 */
199 	}}},
200 	{{T_SEQUENTIAL, T_REMOV,
201 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
202 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
203 		{0, 0, QIC_150},			/* minor 4-7 */
204 		{0, 0, QIC_120},			/* minor 8-11 */
205 		{0, 0, QIC_24}				/* minor 12-15 */
206 	}}},
207 	{{T_SEQUENTIAL, T_REMOV,
208 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
209 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
210 		{0, 0, QIC_150},			/* minor 4-7 */
211 		{0, 0, QIC_120},			/* minor 8-11 */
212 		{0, 0, QIC_24}				/* minor 12-15 */
213 	}}},
214 	{{T_SEQUENTIAL, T_REMOV,
215 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
216 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
217 		{0, 0, QIC_11},				/* minor 4-7 */
218 		{0, 0, QIC_24},				/* minor 8-11 */
219 		{0, 0, QIC_24}				/* minor 12-15 */
220 	}}},
221 	{{T_SEQUENTIAL, T_REMOV,
222 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
223 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
224 		{0, 0, QIC_24},				/* minor 4-7 */
225 		{0, 0, QIC_120},			/* minor 8-11 */
226 		{0, 0, QIC_150}				/* minor 12-15 */
227 	}}},
228 	{{T_SEQUENTIAL, T_REMOV,
229 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
230 		{0, 0, 0},				/* minor 0-3 */
231 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
232 		{0, 0, QIC_150},			/* minor 8-11 */
233 		{0, 0, QIC_120}				/* minor 12-15 */
234 	}}},
235 	{{T_SEQUENTIAL, T_REMOV,
236 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
237 		{0, 0, 0},				/* minor 0-3 */
238 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
239 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
240 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
241 	}}},
242 	{{T_SEQUENTIAL, T_REMOV,
243 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
244 		{0, 0, 0},				/* minor 0-3 */
245 		{0, 0, 0},				/* minor 4-7 */
246 		{0, 0, 0},				/* minor 8-11 */
247 		{0, 0, 0}				/* minor 12-15 */
248 	}}},
249 	{{T_SEQUENTIAL, T_REMOV,
250 	 "STK",      "9490",             ""},
251 				{ST_Q_FORCE_BLKSIZE, 0, {
252 		{0, 0, 0},				/* minor 0-3 */
253 		{0, 0, 0},				/* minor 4-7 */
254 		{0, 0, 0},				/* minor 8-11 */
255 		{0, 0, 0}				/* minor 12-15 */
256 	}}},
257 	{{T_SEQUENTIAL, T_REMOV,
258 	 "STK",      "SD-3",             ""},
259 				{ST_Q_FORCE_BLKSIZE, 0, {
260 		{0, 0, 0},				/* minor 0-3 */
261 		{0, 0, 0},				/* minor 4-7 */
262 		{0, 0, 0},				/* minor 8-11 */
263 		{0, 0, 0}				/* minor 12-15 */
264 	}}},
265 	{{T_SEQUENTIAL, T_REMOV,
266 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
267 		{0, 0, 0},				/* minor 0-3 */
268 		{0, 0, 0},				/* minor 4-7 */
269 		{0, 0, 0},				/* minor 8-11 */
270 		{0, 0, 0}				/* minor 12-15 */
271 	}}},
272 	{{T_SEQUENTIAL, T_REMOV,
273 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
274 		{0, 0, QIC_3095},			/* minor 0-3 */
275 		{0, 0, QIC_3095},			/* minor 4-7 */
276 		{0, 0, QIC_3095},			/* minor 8-11 */
277 		{0, 0, QIC_3095},			/* minor 12-15 */
278 	}}},
279 #if 0
280 	{{T_SEQUENTIAL, T_REMOV,
281 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
282 		{0, 0, 0},				/* minor 0-3 */
283 		{0, 0, 0},				/* minor 4-7 */
284 		{0, 0, 0},				/* minor 8-11 */
285 		{0, 0, 0}				/* minor 12-15 */
286 	}}},
287 #endif
288 	{{T_SEQUENTIAL, T_REMOV,
289 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
290 		{0, 0, 0},			        /* minor 0-3 */
291 		{0, 0, 0},			        /* minor 4-7 */
292 		{0, 0, 0},			        /* minor 8-11 */
293 		{0, 0, 0}			        /* minor 12-15 */
294 	}}},
295 	{{T_SEQUENTIAL, T_REMOV,
296 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
297 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
298 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
299 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
300 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
301 	}}},
302 	{{T_SEQUENTIAL, T_REMOV,
303 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
304 		{0, 0, 0},                              /* minor 0-3 */
305 		{0, 0, 0},                              /* minor 4-7 */
306 		{0, 0, 0},                              /* minor 8-11 */
307 		{0, 0, 0}                               /* minor 12-15 */
308 	}}},
309 	{{T_SEQUENTIAL, T_REMOV,
310 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
311 		{0, 0, 0},			       /* minor 0-3 */
312 		{0, 0, 0},			       /* minor 4-7 */
313 		{0, 0, 0},			       /* minor 8-11 */
314 		{0, 0, 0}			       /* minor 12-15 */
315 	}}},
316 };
317 
318 #define NOEJECT 0
319 #define EJECT 1
320 
321 static void	st_identify_drive(struct st_softc *,
322 		    struct scsipi_inquiry_pattern *);
323 static void	st_loadquirks(struct st_softc *);
324 static int	st_mount_tape(dev_t, int);
325 static void	st_unmount(struct st_softc *, boolean);
326 static int	st_decide_mode(struct st_softc *, boolean);
327 static void	ststart(struct scsipi_periph *);
328 static void	strestart(void *);
329 static void	stdone(struct scsipi_xfer *, int);
330 static int	st_read(struct st_softc *, char *, int, int);
331 static int	st_space(struct st_softc *, int, u_int, int);
332 static int	st_write_filemarks(struct st_softc *, int, int);
333 static int	st_check_eod(struct st_softc *, boolean, int *, int);
334 static int	st_load(struct st_softc *, u_int, int);
335 static int	st_rewind(struct st_softc *, u_int, int);
336 static int	st_interpret_sense(struct scsipi_xfer *);
337 static int	st_touch_tape(struct st_softc *);
338 static int	st_erase(struct st_softc *, int full, int flags);
339 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
340 static int	st_setpos(struct st_softc *, int, u_int32_t *);
341 
342 static const struct scsipi_periphsw st_switch = {
343 	st_interpret_sense,
344 	ststart,
345 	NULL,
346 	stdone
347 };
348 
349 #if	defined(ST_ENABLE_EARLYWARN)
350 #define	ST_INIT_FLAGS	ST_EARLYWARN
351 #else
352 #define	ST_INIT_FLAGS	0
353 #endif
354 
355 /*
356  * The routine called by the low level scsi routine when it discovers
357  * A device suitable for this driver
358  */
359 void
360 stattach(struct device *parent, struct st_softc *st, void *aux)
361 {
362 	struct scsipibus_attach_args *sa = aux;
363 	struct scsipi_periph *periph = sa->sa_periph;
364 
365 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
366 
367 	/*
368 	 * Store information needed to contact our base driver
369 	 */
370 	st->sc_periph = periph;
371 	periph->periph_dev = &st->sc_dev;
372 	periph->periph_switch = &st_switch;
373 
374 	/*
375 	 * Set initial flags
376 	 */
377 
378 	st->flags = ST_INIT_FLAGS;
379 
380 	/*
381 	 * Set up the buf queue for this device
382 	 */
383 	bufq_alloc(&st->buf_queue, "fcfs", 0);
384 
385 	callout_init(&st->sc_callout, 0);
386 
387 	/*
388 	 * Check if the drive is a known criminal and take
389 	 * Any steps needed to bring it into line
390 	 */
391 	st_identify_drive(st, &sa->sa_inqbuf);
392 	/*
393 	 * Use the subdriver to request information regarding the drive.
394 	 */
395 	printf("\n");
396 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "quirks apply, " : "");
397 	if (scsipi_test_unit_ready(periph,
398 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
399 	    st->ops(st, ST_OPS_MODESENSE,
400 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
401 		printf("drive empty\n");
402 	else {
403 		printf("density code %d, ", st->media_density);
404 		if (st->media_blksize > 0)
405 			printf("%d-byte", st->media_blksize);
406 		else
407 			printf("variable");
408 		printf(" blocks, write-%s\n",
409 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
410 	}
411 
412 	st->stats = iostat_alloc(IOSTAT_TAPE, parent, st->sc_dev.dv_xname);
413 
414 #if NRND > 0
415 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
416 			  RND_TYPE_TAPE, 0);
417 #endif
418 }
419 
420 int
421 stactivate(struct device *self, enum devact act)
422 {
423 	int rv = 0;
424 
425 	switch (act) {
426 	case DVACT_ACTIVATE:
427 		rv = EOPNOTSUPP;
428 		break;
429 
430 	case DVACT_DEACTIVATE:
431 		/*
432 		 * Nothing to do; we key off the device's DVF_ACTIVE.
433 		 */
434 		break;
435 	}
436 	return (rv);
437 }
438 
439 int
440 stdetach(struct device *self, int flags)
441 {
442 	struct st_softc *st = device_private(self);
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 	bufq_drain(st->buf_queue);
456 
457 	bufq_free(st->buf_queue);
458 
459 	/* Kill off any pending commands. */
460 	scsipi_kill_pending(st->sc_periph);
461 
462 	splx(s);
463 
464 	/* Nuke the vnodes for any open instances */
465 	mn = STUNIT(device_unit(self));
466 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
467 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
468 
469 	iostat_free(st->stats);
470 
471 #if NRND > 0
472 	/* Unhook the entropy source. */
473 	rnd_detach_source(&st->rnd_source);
474 #endif
475 
476 	return (0);
477 }
478 
479 /*
480  * Use the inquiry routine in 'scsi_base' to get drive info so we can
481  * Further tailor our behaviour.
482  */
483 static void
484 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
485 {
486 	const struct st_quirk_inquiry_pattern *finger;
487 	int priority;
488 
489 	finger = scsipi_inqmatch(inqbuf,
490 	    st_quirk_patterns,
491 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
492 	    sizeof(st_quirk_patterns[0]), &priority);
493 	if (priority != 0) {
494 		st->quirkdata = &finger->quirkdata;
495 		st->drive_quirks = finger->quirkdata.quirks;
496 		st->quirks = finger->quirkdata.quirks;	/* start value */
497 		st->page_0_size = finger->quirkdata.page_0_size;
498 		st_loadquirks(st);
499 	}
500 }
501 
502 /*
503  * initialise the subdevices to the default (QUIRK) state.
504  * this will remove any setting made by the system operator or previous
505  * operations.
506  */
507 static void
508 st_loadquirks(struct st_softc *st)
509 {
510 	int i;
511 	const struct	modes *mode;
512 	struct	modes *mode2;
513 
514 	mode = st->quirkdata->modes;
515 	mode2 = st->modes;
516 	for (i = 0; i < 4; i++) {
517 		memset(mode2, 0, sizeof(struct modes));
518 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
519 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
520 		    DENSITY_SET_BY_USER);
521 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
522 			mode2->blksize = mode->blksize;
523 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
524 		}
525 		if (mode->density) {
526 			mode2->density = mode->density;
527 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
528 		}
529 		mode2->quirks |= mode->quirks;
530 		mode++;
531 		mode2++;
532 	}
533 }
534 
535 /*
536  * open the device.
537  */
538 static int
539 stopen(dev_t dev, int flags, int mode, struct lwp *l)
540 {
541 	u_int stmode, dsty;
542 	int error, sflags, unit, tries, ntries;
543 	struct st_softc *st;
544 	struct scsipi_periph *periph;
545 	struct scsipi_adapter *adapt;
546 
547 	unit = STUNIT(dev);
548 	if (unit >= st_cd.cd_ndevs)
549 		return (ENXIO);
550 	st = st_cd.cd_devs[unit];
551 	if (st == NULL)
552 		return (ENXIO);
553 
554 	stmode = STMODE(dev);
555 	dsty = STDSTY(dev);
556 
557 	periph = st->sc_periph;
558 	adapt = periph->periph_channel->chan_adapter;
559 
560 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
561 	    unit, st_cd.cd_ndevs));
562 
563 
564 	/*
565 	 * Only allow one at a time
566 	 */
567 	if (periph->periph_flags & PERIPH_OPEN) {
568 		printf("%s: already open\n", st->sc_dev.dv_xname);
569 		return (EBUSY);
570 	}
571 
572 	if ((error = scsipi_adapter_addref(adapt)) != 0)
573 		return (error);
574 
575 	/*
576 	 * clear any latched errors.
577 	 */
578 	st->mt_resid = 0;
579 	st->mt_erreg = 0;
580 	st->asc = 0;
581 	st->ascq = 0;
582 
583 	/*
584 	 * Catch any unit attention errors. Be silent about this
585 	 * unless we're already mounted. We ignore media change
586 	 * if we're in control mode or not mounted yet.
587 	 */
588 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
589 #ifdef SCSIDEBUG
590 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
591 #else
592 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
593 #endif
594 	} else
595 		sflags = 0;
596 
597 	/*
598 	 * If we're already mounted or we aren't configured for
599 	 * a mount delay, only try a test unit ready once. Otherwise,
600 	 * try up to ST_MOUNT_DELAY times with a rest interval of
601 	 * one second between each try.
602 	 */
603 
604 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
605 		ntries = 1;
606 	} else {
607 		ntries = ST_MOUNT_DELAY;
608 	}
609 
610 	for (error = tries = 0; tries < ntries; tries++) {
611 		int slpintr, oflags;
612 
613 		/*
614 		 * If we had no error, or we're opening the control mode
615 		 * device, we jump out right away.
616 		 */
617 
618 		error = scsipi_test_unit_ready(periph, sflags);
619 		if (error == 0 || stmode == CTRL_MODE) {
620 			break;
621 		}
622 
623 		/*
624 		 * We had an error.
625 		 *
626 		 * If we're already mounted or we aren't configured for
627 		 * a mount delay, or the error isn't a NOT READY error,
628 		 * skip to the error exit now.
629 		 */
630 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
631 		    (st->mt_key != SKEY_NOT_READY)) {
632 			goto bad;
633 		}
634 
635 		/*
636 		 * clear any latched errors.
637 		 */
638 		st->mt_resid = 0;
639 		st->mt_erreg = 0;
640 		st->asc = 0;
641 		st->ascq = 0;
642 
643 		/*
644 		 * Fake that we have the device open so
645 		 * we block other apps from getting in.
646 		 */
647 
648 		oflags = periph->periph_flags;
649 		periph->periph_flags |= PERIPH_OPEN;
650 
651 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
652 
653 		periph->periph_flags = oflags;	/* restore flags */
654 		if (slpintr) {
655 			goto bad;
656 		}
657 	}
658 
659 
660 	/*
661 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
662 	 * been opened to set defaults and perform other, usually non-I/O
663 	 * related, operations. In this case, do a quick check to see
664 	 * whether the unit actually had a tape loaded (this will be known
665 	 * as to whether or not we got a NOT READY for the above
666 	 * unit attention). If a tape is there, go do a mount sequence.
667 	 */
668 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
669 		periph->periph_flags |= PERIPH_OPEN;
670 		return (0);
671 	}
672 
673 	/*
674 	 * If we get this far and had an error set, that means we failed
675 	 * to pass the 'test unit ready' test for the non-controlmode device,
676 	 * so we bounce the open.
677 	 */
678 
679 	if (error)
680 		return (error);
681 
682 	/*
683 	 * Else, we're now committed to saying we're open.
684 	 */
685 
686 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
687 
688 	/*
689 	 * If it's a different mode, or if the media has been
690 	 * invalidated, unmount the tape from the previous
691 	 * session but continue with open processing
692 	 */
693 	if (st->last_dsty != dsty ||
694 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
695 		st_unmount(st, NOEJECT);
696 
697 	/*
698 	 * If we are not mounted, then we should start a new
699 	 * mount session.
700 	 */
701 	if (!(st->flags & ST_MOUNTED)) {
702 		if ((error = st_mount_tape(dev, flags)) != 0)
703 			goto bad;
704 		st->last_dsty = dsty;
705 	}
706 	if (!(st->quirks & ST_Q_NOPREVENT)) {
707 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
708 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
709 	}
710 
711 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
712 	return (0);
713 
714 bad:
715 	st_unmount(st, NOEJECT);
716 	scsipi_adapter_delref(adapt);
717 	periph->periph_flags &= ~PERIPH_OPEN;
718 	return (error);
719 }
720 
721 /*
722  * close the device.. only called if we are the LAST
723  * occurence of an open device
724  */
725 static int
726 stclose(dev_t dev, int flags, int mode, struct lwp *l)
727 {
728 	int stxx, error = 0;
729 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
730 	struct scsipi_periph *periph = st->sc_periph;
731 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
732 
733 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
734 
735 	/*
736 	 * Make sure that a tape opened in write-only mode will have
737 	 * file marks written on it when closed, even if not written to.
738 	 *
739 	 * This is for SUN compatibility. Actually, the Sun way of
740 	 * things is to:
741 	 *
742 	 *	only write filemarks if there are fmks to be written and
743 	 *   		- open for write (possibly read/write)
744 	 *		- the last operation was a write
745 	 * 	or:
746 	 *		- opened for wronly
747 	 *		- no data was written (including filemarks)
748 	 */
749 
750 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
751 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
752 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
753 		int nm;
754 		error = st_check_eod(st, FALSE, &nm, 0);
755 	}
756 
757 	/*
758 	 * Allow robots to eject tape if needed.
759 	 */
760 	scsipi_prevent(periph, SPAMR_ALLOW,
761 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
762 
763 	switch (STMODE(dev)) {
764 	case NORMAL_MODE:
765 		st_unmount(st, NOEJECT);
766 		break;
767 	case NOREW_MODE:
768 	case CTRL_MODE:
769 		/*
770 		 * Leave mounted unless media seems to have been removed.
771 		 *
772 		 * Otherwise, if we're to terminate a tape with more than one
773 		 * filemark [ and because we're not rewinding here ], backspace
774 		 * one filemark so that later appends will see an unbroken
775 		 * sequence of:
776 		 *
777 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
778 		 */
779 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
780 			st_unmount(st, NOEJECT);
781 		} else if (error == 0) {
782 			/*
783 			 * ST_WRITTEN was preserved from above.
784 			 *
785 			 * All we need to know here is:
786 			 *
787 			 *	Were we writing this tape and was the last
788 			 *	operation a write?
789 			 *
790 			 *	Are there supposed to be 2FM at EOD?
791 			 *
792 			 * If both statements are true, then we backspace
793 			 * one filemark.
794 			 */
795 			stxx |= (st->flags & ST_2FM_AT_EOD);
796 			if ((flags & FWRITE) != 0 &&
797 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
798 				error = st_space(st, -1, SP_FILEMARKS, 0);
799 			}
800 		}
801 		break;
802 	case EJECT_MODE:
803 		st_unmount(st, EJECT);
804 		break;
805 	}
806 
807 	scsipi_wait_drain(periph);
808 
809 	scsipi_adapter_delref(adapt);
810 	periph->periph_flags &= ~PERIPH_OPEN;
811 
812 	return (error);
813 }
814 
815 /*
816  * Start a new mount session.
817  * Copy in all the default parameters from the selected device mode.
818  * and try guess any that seem to be defaulted.
819  */
820 static int
821 st_mount_tape(dev_t dev, int flags)
822 {
823 	int unit;
824 	u_int dsty;
825 	struct st_softc *st;
826 	struct scsipi_periph *periph;
827 	int error = 0;
828 
829 	unit = STUNIT(dev);
830 	dsty = STDSTY(dev);
831 	st = st_cd.cd_devs[unit];
832 	periph = st->sc_periph;
833 
834 	if (st->flags & ST_MOUNTED)
835 		return (0);
836 
837 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
838 	st->flags |= ST_NEW_MOUNT;
839 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
840 	/*
841 	 * If the media is new, then make sure we give it a chance to
842 	 * to do a 'load' instruction.  (We assume it is new.)
843 	 */
844 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
845 		return (error);
846 	/*
847 	 * Throw another dummy instruction to catch
848 	 * 'Unit attention' errors. Many drives give
849 	 * these after doing a Load instruction (with
850 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
851 	 */
852 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
853 
854 	/*
855 	 * Some devices can't tell you much until they have been
856 	 * asked to look at the media. This quirk does this.
857 	 */
858 	if (st->quirks & ST_Q_SENSE_HELP)
859 		if ((error = st_touch_tape(st)) != 0)
860 			return (error);
861 	/*
862 	 * Load the physical device parameters
863 	 * loads: blkmin, blkmax
864 	 */
865 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
866 		return (error);
867 	/*
868 	 * Load the media dependent parameters
869 	 * includes: media_blksize,media_density,numblks
870 	 * As we have a tape in, it should be reflected here.
871 	 * If not you may need the "quirk" above.
872 	 */
873 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
874 		return (error);
875 	/*
876 	 * If we have gained a permanent density from somewhere,
877 	 * then use it in preference to the one supplied by
878 	 * default by the driver.
879 	 */
880 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
881 		st->density = st->modes[dsty].density;
882 	else
883 		st->density = st->media_density;
884 	/*
885 	 * If we have gained a permanent blocksize
886 	 * then use it in preference to the one supplied by
887 	 * default by the driver.
888 	 */
889 	st->flags &= ~ST_FIXEDBLOCKS;
890 	if (st->modeflags[dsty] &
891 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
892 		st->blksize = st->modes[dsty].blksize;
893 		if (st->blksize)
894 			st->flags |= ST_FIXEDBLOCKS;
895 	} else {
896 		if ((error = st_decide_mode(st, FALSE)) != 0)
897 			return (error);
898 	}
899 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
900 		/* ATAPI will return ENODEV for this, and this may be OK */
901 		if (error != ENODEV) {
902 			printf("%s: cannot set selected mode\n",
903 			    st->sc_dev.dv_xname);
904 			return (error);
905 		}
906 	}
907 	st->flags &= ~ST_NEW_MOUNT;
908 	st->flags |= ST_MOUNTED;
909 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
910 	st->blkno = st->fileno = (daddr_t) 0;
911 	return (0);
912 }
913 
914 /*
915  * End the present mount session.
916  * Rewind, and optionally eject the tape.
917  * Reset various flags to indicate that all new
918  * operations require another mount operation
919  */
920 static void
921 st_unmount(struct st_softc *st, boolean eject)
922 {
923 	struct scsipi_periph *periph = st->sc_periph;
924 	int nmarks;
925 
926 	if ((st->flags & ST_MOUNTED) == 0)
927 		return;
928 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
929 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
930 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
931 
932 	/*
933 	 * Section 9.3.3 of the SCSI specs states that a device shall return
934 	 * the density value specified in the last succesfull MODE SELECT
935 	 * after an unload operation, in case it is not able to
936 	 * automatically determine the density of the new medium.
937 	 *
938 	 * So we instruct the device to use the default density, which will
939 	 * prevent the use of stale density values (in particular,
940 	 * in st_touch_tape().
941 	 */
942 	st->density = 0;
943 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
944 		printf("%s: WARNING: cannot revert to default density\n",
945 			st->sc_dev.dv_xname);
946 	}
947 
948 	if (eject) {
949 		if (!(st->quirks & ST_Q_NOPREVENT)) {
950 			scsipi_prevent(periph, SPAMR_ALLOW,
951 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
952 			    XS_CTL_IGNORE_NOT_READY);
953 		}
954 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
955 		st->blkno = st->fileno = (daddr_t) -1;
956 	} else {
957 		st->blkno = st->fileno = (daddr_t) 0;
958 	}
959 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
960 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
961 }
962 
963 /*
964  * Given all we know about the device, media, mode, 'quirks' and
965  * initial operation, make a decision as to how we should be set
966  * to run (regarding blocking and EOD marks)
967  */
968 int
969 st_decide_mode(struct st_softc *st, boolean first_read)
970 {
971 
972 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
973 
974 	/*
975 	 * If the drive can only handle fixed-length blocks and only at
976 	 * one size, perhaps we should just do that.
977 	 */
978 	if (st->blkmin && (st->blkmin == st->blkmax)) {
979 		st->flags |= ST_FIXEDBLOCKS;
980 		st->blksize = st->blkmin;
981 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
982 		    ("blkmin == blkmax of %d\n", st->blkmin));
983 		goto done;
984 	}
985 	/*
986 	 * If the tape density mandates (or even suggests) use of fixed
987 	 * or variable-length blocks, comply.
988 	 */
989 	switch (st->density) {
990 	case HALFINCH_800:
991 	case HALFINCH_1600:
992 	case HALFINCH_6250:
993 	case DDS:
994 		st->flags &= ~ST_FIXEDBLOCKS;
995 		st->blksize = 0;
996 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
997 		    ("density specified variable\n"));
998 		goto done;
999 	case QIC_11:
1000 	case QIC_24:
1001 	case QIC_120:
1002 	case QIC_150:
1003 	case QIC_525:
1004 	case QIC_1320:
1005 	case QIC_3095:
1006 	case QIC_3220:
1007 		st->flags |= ST_FIXEDBLOCKS;
1008 		if (st->media_blksize > 0)
1009 			st->blksize = st->media_blksize;
1010 		else
1011 			st->blksize = DEF_FIXED_BSIZE;
1012 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1013 		    ("density specified fixed\n"));
1014 		goto done;
1015 	}
1016 	/*
1017 	 * If we're about to read the tape, perhaps we should choose
1018 	 * fixed or variable-length blocks and block size according to
1019 	 * what the drive found on the tape.
1020 	 */
1021 	if (first_read &&
1022 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1023 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1024 	    (st->media_blksize == 1024))) {
1025 		if (st->media_blksize > 0)
1026 			st->flags |= ST_FIXEDBLOCKS;
1027 		else
1028 			st->flags &= ~ST_FIXEDBLOCKS;
1029 		st->blksize = st->media_blksize;
1030 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1031 		    ("Used media_blksize of %d\n", st->media_blksize));
1032 		goto done;
1033 	}
1034 	/*
1035 	 * We're getting no hints from any direction.  Choose variable-
1036 	 * length blocks arbitrarily.
1037 	 */
1038 	st->flags &= ~ST_FIXEDBLOCKS;
1039 	st->blksize = 0;
1040 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1041 	    ("Give up and default to variable mode\n"));
1042 
1043 done:
1044 	/*
1045 	 * Decide whether or not to write two file marks to signify end-
1046 	 * of-data.  Make the decision as a function of density.  If
1047 	 * the decision is not to use a second file mark, the SCSI BLANK
1048 	 * CHECK condition code will be recognized as end-of-data when
1049 	 * first read.
1050 	 * (I think this should be a by-product of fixed/variable..julian)
1051 	 */
1052 	switch (st->density) {
1053 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1054 	case QIC_11:
1055 	case QIC_24:
1056 	case QIC_120:
1057 	case QIC_150:
1058 	case QIC_525:
1059 	case QIC_1320:
1060 	case QIC_3095:
1061 	case QIC_3220:
1062 		st->flags &= ~ST_2FM_AT_EOD;
1063 		break;
1064 	default:
1065 		st->flags |= ST_2FM_AT_EOD;
1066 	}
1067 	return (0);
1068 }
1069 
1070 /*
1071  * Actually translate the requested transfer into
1072  * one the physical driver can understand
1073  * The transfer is described by a buf and will include
1074  * only one physical transfer.
1075  */
1076 static void
1077 ststrategy(struct buf *bp)
1078 {
1079 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1080 	int s;
1081 
1082 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1083 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
1084 	/*
1085 	 * If it's a null transfer, return immediatly
1086 	 */
1087 	if (bp->b_bcount == 0)
1088 		goto done;
1089 
1090 	/* If offset is negative, error */
1091 	if (bp->b_blkno < 0) {
1092 		bp->b_error = EINVAL;
1093 		goto done;
1094 	}
1095 
1096 	/*
1097 	 * Odd sized request on fixed drives are verboten
1098 	 */
1099 	if (st->flags & ST_FIXEDBLOCKS) {
1100 		if (bp->b_bcount % st->blksize) {
1101 			printf("%s: bad request, must be multiple of %d\n",
1102 			    st->sc_dev.dv_xname, st->blksize);
1103 			bp->b_error = EIO;
1104 			goto done;
1105 		}
1106 	}
1107 	/*
1108 	 * as are out-of-range requests on variable drives.
1109 	 */
1110 	else if (bp->b_bcount < st->blkmin ||
1111 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1112 		printf("%s: bad request, must be between %d and %d\n",
1113 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1114 		bp->b_error = EIO;
1115 		goto done;
1116 	}
1117 	s = splbio();
1118 
1119 	/*
1120 	 * Place it in the queue of activities for this tape
1121 	 * at the end (a bit silly because we only have on user..
1122 	 * (but it could fork()))
1123 	 */
1124 	BUFQ_PUT(st->buf_queue, bp);
1125 
1126 	/*
1127 	 * Tell the device to get going on the transfer if it's
1128 	 * not doing anything, otherwise just wait for completion
1129 	 * (All a bit silly if we're only allowing 1 open but..)
1130 	 */
1131 	ststart(st->sc_periph);
1132 
1133 	splx(s);
1134 	return;
1135 done:
1136 	/*
1137 	 * Correctly set the buf to indicate a completed xfer
1138 	 */
1139 	bp->b_resid = bp->b_bcount;
1140 	biodone(bp);
1141 	return;
1142 }
1143 
1144 /*
1145  * ststart looks to see if there is a buf waiting for the device
1146  * and that the device is not already busy. If both are true,
1147  * It dequeues the buf and creates a scsi command to perform the
1148  * transfer required. The transfer request will call scsipi_done
1149  * on completion, which will in turn call this routine again
1150  * so that the next queued transfer is performed.
1151  * The bufs are queued by the strategy routine (ststrategy)
1152  *
1153  * This routine is also called after other non-queued requests
1154  * have been made of the scsi driver, to ensure that the queue
1155  * continues to be drained.
1156  * ststart() is called at splbio
1157  */
1158 static void
1159 ststart(struct scsipi_periph *periph)
1160 {
1161 	struct st_softc *st = (void *)periph->periph_dev;
1162 	struct buf *bp;
1163 	struct scsi_rw_tape cmd;
1164 	struct scsipi_xfer *xs;
1165 	int flags, error;
1166 
1167 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1168 	/*
1169 	 * See if there is a buf to do and we are not already
1170 	 * doing one
1171 	 */
1172 	while (periph->periph_active < periph->periph_openings) {
1173 		/* if a special awaits, let it proceed first */
1174 		if (periph->periph_flags & PERIPH_WAITING) {
1175 			periph->periph_flags &= ~PERIPH_WAITING;
1176 			wakeup((void *)periph);
1177 			return;
1178 		}
1179 
1180 		/*
1181 		 * If the device has been unmounted by the user
1182 		 * then throw away all requests until done.
1183 		 */
1184 		if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
1185 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
1186 			if ((bp = BUFQ_GET(st->buf_queue)) != NULL) {
1187 				/* make sure that one implies the other.. */
1188 				periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1189 				bp->b_error = EIO;
1190 				bp->b_resid = bp->b_bcount;
1191 				biodone(bp);
1192 				continue;
1193 			} else {
1194 				return;
1195 			}
1196 		}
1197 
1198 		if ((bp = BUFQ_PEEK(st->buf_queue)) == NULL)
1199 			return;
1200 
1201 		iostat_busy(st->stats);
1202 
1203 		/*
1204 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1205 		 */
1206 		if (st->flags & ST_FIXEDBLOCKS) {
1207 			/*
1208 			 * If we are at a filemark but have not reported it yet
1209 			 * then we should report it now
1210 			 */
1211 			if (st->flags & ST_AT_FILEMARK) {
1212 				if ((bp->b_flags & B_READ) == B_WRITE) {
1213 					/*
1214 					 * Handling of ST_AT_FILEMARK in
1215 					 * st_space will fill in the right file
1216 					 * mark count.
1217 					 * Back up over filemark
1218 					 */
1219 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1220 						BUFQ_GET(st->buf_queue);
1221 						bp->b_error = EIO;
1222 						bp->b_resid = bp->b_bcount;
1223 						biodone(bp);
1224 						continue;
1225 					}
1226 				} else {
1227 					BUFQ_GET(st->buf_queue);
1228 					bp->b_resid = bp->b_bcount;
1229 					bp->b_error = 0;
1230 					st->flags &= ~ST_AT_FILEMARK;
1231 					biodone(bp);
1232 					continue;	/* seek more work */
1233 				}
1234 			}
1235 		}
1236 		/*
1237 		 * If we are at EOM but have not reported it
1238 		 * yet then we should report it now.
1239 		 */
1240 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1241 			BUFQ_GET(st->buf_queue);
1242 			bp->b_resid = bp->b_bcount;
1243 			if (st->flags & ST_EIO_PENDING)
1244 				bp->b_error = EIO;
1245 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1246 			biodone(bp);
1247 			continue;	/* seek more work */
1248 		}
1249 
1250 		/*
1251 		 * Fill out the scsi command
1252 		 */
1253 		memset(&cmd, 0, sizeof(cmd));
1254 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1255 		if ((bp->b_flags & B_READ) == B_WRITE) {
1256 			cmd.opcode = WRITE;
1257 			st->flags &= ~ST_FM_WRITTEN;
1258 			flags |= XS_CTL_DATA_OUT;
1259 		} else {
1260 			cmd.opcode = READ;
1261 			flags |= XS_CTL_DATA_IN;
1262 		}
1263 
1264 		/*
1265 		 * Handle "fixed-block-mode" tape drives by using the
1266 		 * block count instead of the length.
1267 		 */
1268 		if (st->flags & ST_FIXEDBLOCKS) {
1269 			cmd.byte2 |= SRW_FIXED;
1270 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1271 		} else
1272 			_lto3b(bp->b_bcount, cmd.len);
1273 
1274 		/*
1275 		 * Clear 'position updated' indicator
1276 		 */
1277 		st->flags &= ~ST_POSUPDATED;
1278 
1279 		/*
1280 		 * go ask the adapter to do all this for us
1281 		 */
1282 		xs = scsipi_make_xs(periph,
1283 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1284 		    (u_char *)bp->b_data, bp->b_bcount,
1285 		    0, ST_IO_TIME, bp, flags);
1286 		if (__predict_false(xs == NULL)) {
1287 			/*
1288 			 * out of memory. Keep this buffer in the queue, and
1289 			 * retry later.
1290 			 */
1291 			callout_reset(&st->sc_callout, hz / 2, strestart,
1292 			    periph);
1293 			return;
1294 		}
1295 		/*
1296 		 * need to dequeue the buffer before queuing the command,
1297 		 * because cdstart may be called recursively from the
1298 		 * HBA driver
1299 		 */
1300 #ifdef DIAGNOSTIC
1301 		if (BUFQ_GET(st->buf_queue) != bp)
1302 			panic("ststart(): dequeued wrong buf");
1303 #else
1304 		BUFQ_GET(st->buf_queue);
1305 #endif
1306 		error = scsipi_execute_xs(xs);
1307 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
1308 		KASSERT(error == 0);
1309 	} /* go back and see if we can cram more work in.. */
1310 }
1311 
1312 static void
1313 strestart(void *v)
1314 {
1315 	int s = splbio();
1316 	ststart((struct scsipi_periph *)v);
1317 	splx(s);
1318 }
1319 
1320 
1321 static void
1322 stdone(struct scsipi_xfer *xs, int error)
1323 {
1324 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1325 	struct buf *bp = xs->bp;
1326 
1327 	if (bp) {
1328 		bp->b_error = error;
1329 		bp->b_resid = xs->resid;
1330 		/*
1331 		 * buggy device ? A SDLT320 can report an info
1332 		 * field of 0x3de8000 on a Media Error/Write Error
1333 		 * for this CBD: 0x0a 00 00 80 00 00
1334 		 */
1335 		if (bp->b_resid > bp->b_bcount || bp->b_resid < 0)
1336 			bp->b_resid = bp->b_bcount;
1337 
1338 		if ((bp->b_flags & B_READ) == B_WRITE)
1339 			st->flags |= ST_WRITTEN;
1340 		else
1341 			st->flags &= ~ST_WRITTEN;
1342 
1343 		iostat_unbusy(st->stats, bp->b_bcount,
1344 			     ((bp->b_flags & B_READ) == B_READ));
1345 
1346 #if NRND > 0
1347 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
1348 #endif
1349 
1350 		if ((st->flags & ST_POSUPDATED) == 0) {
1351 			if (error) {
1352 				st->fileno = st->blkno = -1;
1353 			} else if (st->blkno != -1) {
1354 				if (st->flags & ST_FIXEDBLOCKS)
1355 					st->blkno +=
1356 					    (bp->b_bcount / st->blksize);
1357 				else
1358 					st->blkno++;
1359 			}
1360 		}
1361 
1362 		biodone(bp);
1363 	}
1364 }
1365 
1366 static int
1367 stread(dev_t dev, struct uio *uio, int iomode)
1368 {
1369 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1370 
1371 	return (physio(ststrategy, NULL, dev, B_READ,
1372 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1373 }
1374 
1375 static int
1376 stwrite(dev_t dev, struct uio *uio, int iomode)
1377 {
1378 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1379 
1380 	return (physio(ststrategy, NULL, dev, B_WRITE,
1381 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1382 }
1383 
1384 /*
1385  * Perform special action on behalf of the user;
1386  * knows about the internals of this device
1387  */
1388 static int
1389 stioctl(dev_t dev, u_long cmd, void *arg, int flag, struct lwp *l)
1390 {
1391 	int error = 0;
1392 	int unit;
1393 	int number, nmarks, dsty;
1394 	int flags;
1395 	struct st_softc *st;
1396 	int hold_blksize;
1397 	u_int8_t hold_density;
1398 	struct mtop *mt = (struct mtop *) arg;
1399 
1400 	/*
1401 	 * Find the device that the user is talking about
1402 	 */
1403 	flags = 0;		/* give error messages, act on errors etc. */
1404 	unit = STUNIT(dev);
1405 	dsty = STDSTY(dev);
1406 	st = st_cd.cd_devs[unit];
1407 	hold_blksize = st->blksize;
1408 	hold_density = st->density;
1409 
1410 	switch ((u_int) cmd) {
1411 
1412 	case MTIOCGET: {
1413 		struct mtget *g = (struct mtget *) arg;
1414 		/*
1415 		 * (to get the current state of READONLY)
1416 		 */
1417 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1418 		if (error) {
1419 			/*
1420 			 * Ignore the error if in control mode;
1421 			 * this is mandated by st(4).
1422 			 */
1423 			if (STMODE(dev) != CTRL_MODE)
1424 				break;
1425 			error = 0;
1426 		}
1427 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1428 		memset(g, 0, sizeof(struct mtget));
1429 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1430 		g->mt_blksiz = st->blksize;
1431 		g->mt_density = st->density;
1432 		g->mt_mblksiz[0] = st->modes[0].blksize;
1433 		g->mt_mblksiz[1] = st->modes[1].blksize;
1434 		g->mt_mblksiz[2] = st->modes[2].blksize;
1435 		g->mt_mblksiz[3] = st->modes[3].blksize;
1436 		g->mt_mdensity[0] = st->modes[0].density;
1437 		g->mt_mdensity[1] = st->modes[1].density;
1438 		g->mt_mdensity[2] = st->modes[2].density;
1439 		g->mt_mdensity[3] = st->modes[3].density;
1440 		g->mt_fileno = st->fileno;
1441 		g->mt_blkno = st->blkno;
1442 		if (st->flags & ST_READONLY)
1443 			g->mt_dsreg |= MT_DS_RDONLY;
1444 		if (st->flags & ST_MOUNTED)
1445 			g->mt_dsreg |= MT_DS_MOUNTED;
1446 		g->mt_resid = st->mt_resid;
1447 		g->mt_erreg = st->mt_erreg;
1448 		/*
1449 		 * clear latched errors.
1450 		 */
1451 		st->mt_resid = 0;
1452 		st->mt_erreg = 0;
1453 		st->asc = 0;
1454 		st->ascq = 0;
1455 		break;
1456 	}
1457 	case MTIOCTOP: {
1458 
1459 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1460 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1461 			mt->mt_count));
1462 
1463 		/* compat: in U*x it is a short */
1464 		number = mt->mt_count;
1465 		switch ((short) (mt->mt_op)) {
1466 		case MTWEOF:	/* write an end-of-file record */
1467 			error = st_write_filemarks(st, number, flags);
1468 			break;
1469 		case MTBSF:	/* backward space file */
1470 			number = -number;
1471 		case MTFSF:	/* forward space file */
1472 			error = st_check_eod(st, FALSE, &nmarks, flags);
1473 			if (!error)
1474 				error = st_space(st, number - nmarks,
1475 				    SP_FILEMARKS, flags);
1476 			break;
1477 		case MTBSR:	/* backward space record */
1478 			number = -number;
1479 		case MTFSR:	/* forward space record */
1480 			error = st_check_eod(st, true, &nmarks, flags);
1481 			if (!error)
1482 				error = st_space(st, number, SP_BLKS, flags);
1483 			break;
1484 		case MTREW:	/* rewind */
1485 			error = st_rewind(st, 0, flags);
1486 			break;
1487 		case MTOFFL:	/* rewind and put the drive offline */
1488 			st_unmount(st, EJECT);
1489 			break;
1490 		case MTNOP:	/* no operation, sets status only */
1491 			break;
1492 		case MTRETEN:	/* retension the tape */
1493 			error = st_load(st, LD_RETENSION, flags);
1494 			if (!error)
1495 				error = st_load(st, LD_LOAD, flags);
1496 			break;
1497 		case MTEOM:	/* forward space to end of media */
1498 			error = st_check_eod(st, FALSE, &nmarks, flags);
1499 			if (!error)
1500 				error = st_space(st, 1, SP_EOM, flags);
1501 			break;
1502 		case MTCACHE:	/* enable controller cache */
1503 			st->flags &= ~ST_DONTBUFFER;
1504 			goto try_new_value;
1505 		case MTNOCACHE:	/* disable controller cache */
1506 			st->flags |= ST_DONTBUFFER;
1507 			goto try_new_value;
1508 		case MTERASE:	/* erase volume */
1509 			error = st_erase(st, number, flags);
1510 			break;
1511 		case MTSETBSIZ:	/* Set block size for device */
1512 #ifdef	NOTYET
1513 			if (!(st->flags & ST_NEW_MOUNT)) {
1514 				uprintf("re-mount tape before changing blocksize");
1515 				error = EINVAL;
1516 				break;
1517 			}
1518 #endif
1519 			if (number == 0)
1520 				st->flags &= ~ST_FIXEDBLOCKS;
1521 			else {
1522 				if ((st->blkmin || st->blkmax) &&
1523 				    (number < st->blkmin ||
1524 				    number > st->blkmax)) {
1525 					error = EINVAL;
1526 					break;
1527 				}
1528 				st->flags |= ST_FIXEDBLOCKS;
1529 			}
1530 			st->blksize = number;
1531 			st->flags |= ST_BLOCK_SET;	/*XXX */
1532 			goto try_new_value;
1533 
1534 		case MTSETDNSTY:	/* Set density for device and mode */
1535 			/*
1536 			 * Any number >= 0 and <= 0xff is legal. Numbers
1537 			 * above 0x80 are 'vendor unique'.
1538 			 */
1539 			if (number < 0 || number > 255) {
1540 				error = EINVAL;
1541 				break;
1542 			} else
1543 				st->density = number;
1544 			goto try_new_value;
1545 
1546 		case MTCMPRESS:
1547 			error = st->ops(st, (number == 0) ?
1548 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1549 			    XS_CTL_SILENT);
1550 			break;
1551 
1552 		case MTEWARN:
1553 			if (number)
1554 				st->flags |= ST_EARLYWARN;
1555 			else
1556 				st->flags &= ~ST_EARLYWARN;
1557 			break;
1558 
1559 		default:
1560 			error = EINVAL;
1561 		}
1562 		break;
1563 	}
1564 	case MTIOCIEOT:
1565 	case MTIOCEEOT:
1566 		break;
1567 
1568 	case MTIOCRDSPOS:
1569 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1570 		break;
1571 
1572 	case MTIOCRDHPOS:
1573 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1574 		break;
1575 
1576 	case MTIOCSLOCATE:
1577 		error = st_setpos(st, 0, (u_int32_t *) arg);
1578 		break;
1579 
1580 	case MTIOCHLOCATE:
1581 		error = st_setpos(st, 1, (u_int32_t *) arg);
1582 		break;
1583 
1584 
1585 	default:
1586 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1587 					flag, l);
1588 		break;
1589 	}
1590 	return (error);
1591 /*-----------------------------*/
1592 try_new_value:
1593 	/*
1594 	 * Check that the mode being asked for is aggreeable to the
1595 	 * drive. If not, put it back the way it was.
1596 	 *
1597 	 * If in control mode, we can make (persistent) mode changes
1598 	 * even if no medium is loaded (see st(4)).
1599 	 */
1600 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1601 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1602 		/* put it back as it was */
1603 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1604 		st->density = hold_density;
1605 		st->blksize = hold_blksize;
1606 		if (st->blksize)
1607 			st->flags |= ST_FIXEDBLOCKS;
1608 		else
1609 			st->flags &= ~ST_FIXEDBLOCKS;
1610 		return (error);
1611 	}
1612 	/*
1613 	 * As the drive liked it, if we are setting a new default,
1614 	 * set it into the structures as such.
1615 	 *
1616 	 * The means for deciding this are not finalised yet- but
1617 	 * if the device was opened in Control Mode, the values
1618 	 * are persistent now across mounts.
1619 	 */
1620 	if (STMODE(dev) == CTRL_MODE) {
1621 		switch ((short) (mt->mt_op)) {
1622 		case MTSETBSIZ:
1623 			st->modes[dsty].blksize = st->blksize;
1624 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1625 			break;
1626 		case MTSETDNSTY:
1627 			st->modes[dsty].density = st->density;
1628 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1629 			break;
1630 		}
1631 	}
1632 	return (0);
1633 }
1634 
1635 /*
1636  * Do a synchronous read.
1637  */
1638 static int
1639 st_read(struct st_softc *st, char *bf, int size, int flags)
1640 {
1641 	struct scsi_rw_tape cmd;
1642 
1643 	/*
1644 	 * If it's a null transfer, return immediatly
1645 	 */
1646 	if (size == 0)
1647 		return (0);
1648 	memset(&cmd, 0, sizeof(cmd));
1649 	cmd.opcode = READ;
1650 	if (st->flags & ST_FIXEDBLOCKS) {
1651 		cmd.byte2 |= SRW_FIXED;
1652 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1653 		    cmd.len);
1654 	} else
1655 		_lto3b(size, cmd.len);
1656 	return (scsipi_command(st->sc_periph,
1657 	    (void *)&cmd, sizeof(cmd), (void *)bf, size, 0, ST_IO_TIME, NULL,
1658 	    flags | XS_CTL_DATA_IN));
1659 }
1660 
1661 /*
1662  * issue an erase command
1663  */
1664 static int
1665 st_erase(struct st_softc *st, int full, int flags)
1666 {
1667 	int tmo;
1668 	struct scsi_erase cmd;
1669 
1670 	/*
1671 	 * Full erase means set LONG bit in erase command, which asks
1672 	 * the drive to erase the entire unit.  Without this bit, we're
1673 	 * asking the drive to write an erase gap.
1674 	 */
1675 	memset(&cmd, 0, sizeof(cmd));
1676 	cmd.opcode = ERASE;
1677 	if (full) {
1678 		cmd.byte2 = SE_LONG;
1679 		tmo = ST_SPC_TIME;
1680 	} else {
1681 		tmo = ST_IO_TIME;
1682 	}
1683 
1684 	/*
1685 	 * XXX We always do this asynchronously, for now, unless the device
1686 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1687 	 * want to (eventually) to it synchronously?
1688 	 */
1689 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1690 		cmd.byte2 |= SE_IMMED;
1691 
1692 	return (scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1693 	    ST_RETRIES, tmo, NULL, flags));
1694 }
1695 
1696 /*
1697  * skip N blocks/filemarks/seq filemarks/eom
1698  */
1699 static int
1700 st_space(struct st_softc *st, int number, u_int what, int flags)
1701 {
1702 	struct scsi_space cmd;
1703 	int error;
1704 
1705 	switch (what) {
1706 	case SP_BLKS:
1707 		if (st->flags & ST_PER_ACTION) {
1708 			if (number > 0) {
1709 				st->flags &= ~ST_PER_ACTION;
1710 				return (EIO);
1711 			} else if (number < 0) {
1712 				if (st->flags & ST_AT_FILEMARK) {
1713 					/*
1714 					 * Handling of ST_AT_FILEMARK
1715 					 * in st_space will fill in the
1716 					 * right file mark count.
1717 					 */
1718 					error = st_space(st, 0, SP_FILEMARKS,
1719 					    flags);
1720 					if (error)
1721 						return (error);
1722 				}
1723 				if (st->flags & ST_BLANK_READ) {
1724 					st->flags &= ~ST_BLANK_READ;
1725 					return (EIO);
1726 				}
1727 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1728 			}
1729 		}
1730 		break;
1731 	case SP_FILEMARKS:
1732 		if (st->flags & ST_EIO_PENDING) {
1733 			if (number > 0) {
1734 				/* pretend we just discovered the error */
1735 				st->flags &= ~ST_EIO_PENDING;
1736 				return (EIO);
1737 			} else if (number < 0) {
1738 				/* back away from the error */
1739 				st->flags &= ~ST_EIO_PENDING;
1740 			}
1741 		}
1742 		if (st->flags & ST_AT_FILEMARK) {
1743 			st->flags &= ~ST_AT_FILEMARK;
1744 			number--;
1745 		}
1746 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1747 			/* back away from unwritten tape */
1748 			st->flags &= ~ST_BLANK_READ;
1749 			number++;	/* XXX dubious */
1750 		}
1751 		break;
1752 	case SP_EOM:
1753 		if (st->flags & ST_EOM_PENDING) {
1754 			/* we're already there */
1755 			st->flags &= ~ST_EOM_PENDING;
1756 			return (0);
1757 		}
1758 		if (st->flags & ST_EIO_PENDING) {
1759 			/* pretend we just discovered the error */
1760 			st->flags &= ~ST_EIO_PENDING;
1761 			return (EIO);
1762 		}
1763 		if (st->flags & ST_AT_FILEMARK)
1764 			st->flags &= ~ST_AT_FILEMARK;
1765 		break;
1766 	}
1767 	if (number == 0)
1768 		return (0);
1769 
1770 	memset(&cmd, 0, sizeof(cmd));
1771 	cmd.opcode = SPACE;
1772 	cmd.byte2 = what;
1773 	_lto3b(number, cmd.number);
1774 
1775 	st->flags &= ~ST_POSUPDATED;
1776 	st->last_ctl_resid = 0;
1777 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1778 	    0, ST_SPC_TIME, NULL, flags);
1779 
1780 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1781 		number = number - st->last_ctl_resid;
1782 		if (what == SP_BLKS) {
1783 			if (st->blkno != -1) {
1784 				st->blkno += number;
1785 			}
1786 		} else if (what == SP_FILEMARKS) {
1787 			if (st->fileno != -1) {
1788 				st->fileno += number;
1789 				if (number > 0) {
1790 					st->blkno = 0;
1791 				} else if (number < 0) {
1792 					st->blkno = -1;
1793 				}
1794 			}
1795 		} else if (what == SP_EOM) {
1796 			/*
1797 			 * This loses us relative position.
1798 			 */
1799 			st->fileno = st->blkno = -1;
1800 		}
1801 	}
1802 	return (error);
1803 }
1804 
1805 /*
1806  * write N filemarks
1807  */
1808 static int
1809 st_write_filemarks(struct st_softc *st, int number, int flags)
1810 {
1811 	int error;
1812 	struct scsi_write_filemarks cmd;
1813 
1814 	/*
1815 	 * It's hard to write a negative number of file marks.
1816 	 * Don't try.
1817 	 */
1818 	if (number < 0)
1819 		return (EINVAL);
1820 	switch (number) {
1821 	case 0:		/* really a command to sync the drive's buffers */
1822 		break;
1823 	case 1:
1824 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1825 			st->flags &= ~ST_WRITTEN;
1826 		else
1827 			st->flags |= ST_FM_WRITTEN;
1828 		st->flags &= ~ST_PER_ACTION;
1829 		break;
1830 	default:
1831 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1832 	}
1833 
1834 	memset(&cmd, 0, sizeof(cmd));
1835 	cmd.opcode = WRITE_FILEMARKS;
1836 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1837 		cmd.byte2 = SR_IMMED;
1838 	/*
1839 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1840 	 * WRITE_FILEMARKS is still used to flush the buffer
1841 	 */
1842 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1843 		_lto3b(number, cmd.number);
1844 
1845 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1846 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1847 	    0, ST_IO_TIME * 4, NULL, flags);
1848 	if (error == 0 && st->fileno != -1) {
1849 		st->fileno += number;
1850 	}
1851 	return (error);
1852 }
1853 
1854 /*
1855  * Make sure the right number of file marks is on tape if the
1856  * tape has been written.  If the position argument is true,
1857  * leave the tape positioned where it was originally.
1858  *
1859  * nmarks returns the number of marks to skip (or, if position
1860  * true, which were skipped) to get back original position.
1861  */
1862 static int
1863 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
1864 {
1865 	int error;
1866 
1867 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1868 	default:
1869 		*nmarks = 0;
1870 		return (0);
1871 	case ST_WRITTEN:
1872 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1873 		*nmarks = 1;
1874 		break;
1875 	case ST_WRITTEN | ST_2FM_AT_EOD:
1876 		*nmarks = 2;
1877 	}
1878 	error = st_write_filemarks(st, *nmarks, flags);
1879 	if (position && !error)
1880 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1881 	return (error);
1882 }
1883 
1884 /*
1885  * load/unload/retension
1886  */
1887 static int
1888 st_load(struct st_softc *st, u_int type, int flags)
1889 {
1890 	int error;
1891 	struct scsi_load cmd;
1892 
1893 	if (type != LD_LOAD) {
1894 		int nmarks;
1895 
1896 		error = st_check_eod(st, FALSE, &nmarks, flags);
1897 		if (error) {
1898 			printf("%s: failed to write closing filemarks at "
1899 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1900 			return (error);
1901 		}
1902 	}
1903 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1904 		if (type == LD_LOAD) {
1905 			/*
1906 			 * If we ignore loads, at least we should try a rewind.
1907 			 */
1908 			return st_rewind(st, 0, flags);
1909 		}
1910 		/* otherwise, we should do what's asked of us */
1911 	}
1912 
1913 	memset(&cmd, 0, sizeof(cmd));
1914 	cmd.opcode = LOAD;
1915 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1916 		cmd.byte2 = SR_IMMED;
1917 	cmd.how = type;
1918 
1919 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1920 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
1921 	if (error) {
1922 		printf("%s: error %d in st_load (op %d)\n",
1923 		    st->sc_dev.dv_xname, error, type);
1924 	}
1925 	return (error);
1926 }
1927 
1928 /*
1929  *  Rewind the device
1930  */
1931 static int
1932 st_rewind(struct st_softc *st, u_int immediate, int flags)
1933 {
1934 	struct scsi_rewind cmd;
1935 	int error;
1936 	int nmarks;
1937 	int timeout;
1938 
1939 	error = st_check_eod(st, FALSE, &nmarks, flags);
1940 	if (error) {
1941 		printf("%s: failed to write closing filemarks at "
1942 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1943 		return (error);
1944 	}
1945 	st->flags &= ~ST_PER_ACTION;
1946 
1947 	/* If requestor asked for immediate response, set a short timeout */
1948 	timeout = immediate ? ST_CTL_TIME : ST_SPC_TIME;
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, timeout, 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, void *va,
2402     size_t size)
2403 {
2404 
2405 	/* Not implemented. */
2406 	return (ENXIO);
2407 }
2408