xref: /netbsd-src/sys/dev/scsipi/st.c (revision 9c1da17e908379b8a470f1117a6395bd6a0ca559)
1 /*	$NetBSD: st.c,v 1.184 2005/08/13 10:50:50 blymn 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 1.184 2005/08/13 10:50:50 blymn 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/tape.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 struct tape *
111 drive_attach(char *name);
112 
113 static dev_type_open(stopen);
114 static dev_type_close(stclose);
115 static dev_type_read(stread);
116 static dev_type_write(stwrite);
117 static dev_type_ioctl(stioctl);
118 static dev_type_strategy(ststrategy);
119 static dev_type_dump(stdump);
120 
121 const struct bdevsw st_bdevsw = {
122 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
123 };
124 
125 const struct cdevsw st_cdevsw = {
126 	stopen, stclose, stread, stwrite, stioctl,
127 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
128 };
129 
130 /*
131  * Define various devices that we know mis-behave in some way,
132  * and note how they are bad, so we can correct for them
133  */
134 
135 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
136 	{{T_SEQUENTIAL, T_REMOV,
137 	 "        ", "                ", "    "}, {0, 0, {
138 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
139 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
140 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
141 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
142 	}}},
143 	{{T_SEQUENTIAL, T_REMOV,
144 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
145 		{0, 0, 0},				/* minor 0-3 */
146 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
147 		{0, 0, QIC_150},			/* minor 8-11 */
148 		{0, 0, QIC_120}				/* minor 12-15 */
149 	}}},
150  	{{T_SEQUENTIAL, T_REMOV,
151  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
152 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
153 		{0, 0, QIC_525},			/* minor 4-7 */
154 		{0, 0, QIC_150},			/* minor 8-11 */
155 		{0, 0, QIC_120}				/* minor 12-15 */
156 	}}},
157 	{{T_SEQUENTIAL, T_REMOV,
158 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
159 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
160 		{0, 0, 0},				/* minor 4-7 */
161 		{0, 0, 0},				/* minor 8-11 */
162 		{0, 0, 0}				/* minor 12-15 */
163 	}}},
164 	/*
165 	 * lacking a manual for the 4200, it's not clear what the
166 	 * specific density codes should be- the device is a 2.5GB
167 	 * capable QIC drive, those density codes aren't readily
168 	 * availabel. The 'default' will just have to do.
169 	 */
170  	{{T_SEQUENTIAL, T_REMOV,
171  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
172 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
173 		{0, 0, QIC_525},			/* minor 4-7 */
174 		{0, 0, QIC_150},			/* minor 8-11 */
175 		{0, 0, QIC_120}				/* minor 12-15 */
176 	}}},
177 	/*
178 	 * At least -005 and -007 need this.  I'll assume they all do unless I
179 	 * hear otherwise.  - mycroft, 31MAR1994
180 	 */
181 	{{T_SEQUENTIAL, T_REMOV,
182 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
183 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
184 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
185 		{0, 0, QIC_150},			/* minor 8-11 */
186 		{0, 0, QIC_120}				/* minor 12-15 */
187 	}}},
188 	/*
189 	 * One user reports that this works for his tape drive.  It probably
190 	 * needs more work.  - mycroft, 09APR1994
191 	 */
192 	{{T_SEQUENTIAL, T_REMOV,
193 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
194 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
195 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
196 		{0, 0, QIC_150},			/* minor 8-11 */
197 		{0, 0, QIC_120}				/* minor 12-15 */
198 	}}},
199 	{{T_SEQUENTIAL, T_REMOV,
200 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
201 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
202 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
203 		{0, 0, QIC_150},			/* minor 8-11 */
204 		{0, 0, QIC_120}				/* minor 12-15 */
205 	}}},
206 	{{T_SEQUENTIAL, T_REMOV,
207 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
208 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
209 		{0, 0, QIC_150},			/* minor 4-7 */
210 		{0, 0, QIC_120},			/* minor 8-11 */
211 		{0, 0, QIC_24}				/* minor 12-15 */
212 	}}},
213 	{{T_SEQUENTIAL, T_REMOV,
214 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
215 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
216 		{0, 0, QIC_150},			/* minor 4-7 */
217 		{0, 0, QIC_120},			/* minor 8-11 */
218 		{0, 0, QIC_24}				/* minor 12-15 */
219 	}}},
220 	{{T_SEQUENTIAL, T_REMOV,
221 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
222 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
223 		{0, 0, QIC_11},				/* minor 4-7 */
224 		{0, 0, QIC_24},				/* minor 8-11 */
225 		{0, 0, QIC_24}				/* minor 12-15 */
226 	}}},
227 	{{T_SEQUENTIAL, T_REMOV,
228 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
229 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
230 		{0, 0, QIC_24},				/* minor 4-7 */
231 		{0, 0, QIC_120},			/* minor 8-11 */
232 		{0, 0, QIC_150}				/* minor 12-15 */
233 	}}},
234 	{{T_SEQUENTIAL, T_REMOV,
235 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
236 		{0, 0, 0},				/* minor 0-3 */
237 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
238 		{0, 0, QIC_150},			/* minor 8-11 */
239 		{0, 0, QIC_120}				/* minor 12-15 */
240 	}}},
241 	{{T_SEQUENTIAL, T_REMOV,
242 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
243 		{0, 0, 0},				/* minor 0-3 */
244 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
245 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
246 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
247 	}}},
248 	{{T_SEQUENTIAL, T_REMOV,
249 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
250 		{0, 0, 0},				/* minor 0-3 */
251 		{0, 0, 0},				/* minor 4-7 */
252 		{0, 0, 0},				/* minor 8-11 */
253 		{0, 0, 0}				/* minor 12-15 */
254 	}}},
255 	{{T_SEQUENTIAL, T_REMOV,
256 	 "STK",      "9490",             ""},
257 				{ST_Q_FORCE_BLKSIZE, 0, {
258 		{0, 0, 0},				/* minor 0-3 */
259 		{0, 0, 0},				/* minor 4-7 */
260 		{0, 0, 0},				/* minor 8-11 */
261 		{0, 0, 0}				/* minor 12-15 */
262 	}}},
263 	{{T_SEQUENTIAL, T_REMOV,
264 	 "STK",      "SD-3",             ""},
265 				{ST_Q_FORCE_BLKSIZE, 0, {
266 		{0, 0, 0},				/* minor 0-3 */
267 		{0, 0, 0},				/* minor 4-7 */
268 		{0, 0, 0},				/* minor 8-11 */
269 		{0, 0, 0}				/* minor 12-15 */
270 	}}},
271 	{{T_SEQUENTIAL, T_REMOV,
272 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
273 		{0, 0, 0},				/* minor 0-3 */
274 		{0, 0, 0},				/* minor 4-7 */
275 		{0, 0, 0},				/* minor 8-11 */
276 		{0, 0, 0}				/* minor 12-15 */
277 	}}},
278 	{{T_SEQUENTIAL, T_REMOV,
279 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
280 		{0, 0, QIC_3095},			/* minor 0-3 */
281 		{0, 0, QIC_3095},			/* minor 4-7 */
282 		{0, 0, QIC_3095},			/* minor 8-11 */
283 		{0, 0, QIC_3095},			/* minor 12-15 */
284 	}}},
285 #if 0
286 	{{T_SEQUENTIAL, T_REMOV,
287 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
288 		{0, 0, 0},				/* minor 0-3 */
289 		{0, 0, 0},				/* minor 4-7 */
290 		{0, 0, 0},				/* minor 8-11 */
291 		{0, 0, 0}				/* minor 12-15 */
292 	}}},
293 #endif
294 	{{T_SEQUENTIAL, T_REMOV,
295 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
296 		{0, 0, 0},			        /* minor 0-3 */
297 		{0, 0, 0},			        /* minor 4-7 */
298 		{0, 0, 0},			        /* minor 8-11 */
299 		{0, 0, 0}			        /* minor 12-15 */
300 	}}},
301 	{{T_SEQUENTIAL, T_REMOV,
302 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
303 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
304 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
305 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
306 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
307 	}}},
308 	{{T_SEQUENTIAL, T_REMOV,
309 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
310 		{0, 0, 0},                              /* minor 0-3 */
311 		{0, 0, 0},                              /* minor 4-7 */
312 		{0, 0, 0},                              /* minor 8-11 */
313 		{0, 0, 0}                               /* minor 12-15 */
314 	}}},
315 	{{T_SEQUENTIAL, T_REMOV,
316 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
317 		{0, 0, 0},			       /* minor 0-3 */
318 		{0, 0, 0},			       /* minor 4-7 */
319 		{0, 0, 0},			       /* minor 8-11 */
320 		{0, 0, 0}			       /* minor 12-15 */
321 	}}},
322 };
323 
324 #define NOEJECT 0
325 #define EJECT 1
326 
327 static void	st_identify_drive(struct st_softc *,
328 		    struct scsipi_inquiry_pattern *);
329 static void	st_loadquirks(struct st_softc *);
330 static int	st_mount_tape(dev_t, int);
331 static void	st_unmount(struct st_softc *, boolean);
332 static int	st_decide_mode(struct st_softc *, boolean);
333 static void	ststart(struct scsipi_periph *);
334 static void	strestart(void *);
335 static void	stdone(struct scsipi_xfer *, int);
336 static int	st_read(struct st_softc *, char *, int, int);
337 static int	st_space(struct st_softc *, int, u_int, int);
338 static int	st_write_filemarks(struct st_softc *, int, int);
339 static int	st_check_eod(struct st_softc *, boolean, int *, int);
340 static int	st_load(struct st_softc *, u_int, int);
341 static int	st_rewind(struct st_softc *, u_int, int);
342 static int	st_interpret_sense(struct scsipi_xfer *);
343 static int	st_touch_tape(struct st_softc *);
344 static int	st_erase(struct st_softc *, int full, int flags);
345 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
346 static int	st_setpos(struct st_softc *, int, u_int32_t *);
347 
348 static const struct scsipi_periphsw st_switch = {
349 	st_interpret_sense,
350 	ststart,
351 	NULL,
352 	stdone
353 };
354 
355 /*
356  * A global list of all tape drives attached to the system.  May grow or
357  * shrink over time.
358  */
359 struct  tapelist_head tapelist = TAILQ_HEAD_INITIALIZER(tapelist);
360 int     tape_count = 0;             /* number of drives in global tapelist */
361 struct simplelock tapelist_slock = SIMPLELOCK_INITIALIZER;
362 
363 #if	defined(ST_ENABLE_EARLYWARN)
364 #define	ST_INIT_FLAGS	ST_EARLYWARN
365 #else
366 #define	ST_INIT_FLAGS	0
367 #endif
368 
369 /*
370  * The routine called by the low level scsi routine when it discovers
371  * A device suitable for this driver
372  */
373 void
374 stattach(struct device *parent, struct st_softc *st, void *aux)
375 {
376 	struct scsipibus_attach_args *sa = aux;
377 	struct scsipi_periph *periph = sa->sa_periph;
378 
379 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
380 
381 	/*
382 	 * Store information needed to contact our base driver
383 	 */
384 	st->sc_periph = periph;
385 	periph->periph_dev = &st->sc_dev;
386 	periph->periph_switch = &st_switch;
387 
388 	/*
389 	 * Set initial flags
390 	 */
391 
392 	st->flags = ST_INIT_FLAGS;
393 
394 	/*
395 	 * Set up the buf queue for this device
396 	 */
397 	bufq_alloc(&st->buf_queue, BUFQ_FCFS);
398 
399 	callout_init(&st->sc_callout);
400 
401 	/*
402 	 * Check if the drive is a known criminal and take
403 	 * Any steps needed to bring it into line
404 	 */
405 	st_identify_drive(st, &sa->sa_inqbuf);
406 	/*
407 	 * Use the subdriver to request information regarding the drive.
408 	 */
409 	printf("\n");
410 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "quirks apply, " : "");
411 	if (scsipi_test_unit_ready(periph,
412 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
413 	    st->ops(st, ST_OPS_MODESENSE,
414 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
415 		printf("drive empty\n");
416 	else {
417 		printf("density code %d, ", st->media_density);
418 		if (st->media_blksize > 0)
419 			printf("%d-byte", st->media_blksize);
420 		else
421 			printf("variable");
422 		printf(" blocks, write-%s\n",
423 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
424 	}
425 
426 	st->stats = drive_attach(st->sc_dev.dv_xname);
427 
428 #if NRND > 0
429 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
430 			  RND_TYPE_TAPE, 0);
431 #endif
432 }
433 
434 int
435 stactivate(struct device *self, enum devact act)
436 {
437 	int rv = 0;
438 
439 	switch (act) {
440 	case DVACT_ACTIVATE:
441 		rv = EOPNOTSUPP;
442 		break;
443 
444 	case DVACT_DEACTIVATE:
445 		/*
446 		 * Nothing to do; we key off the device's DVF_ACTIVE.
447 		 */
448 		break;
449 	}
450 	return (rv);
451 }
452 
453 int
454 stdetach(struct device *self, int flags)
455 {
456 	struct st_softc *st = (struct st_softc *)self;
457 	int s, bmaj, cmaj, mn;
458 
459 	/* locate the major number */
460 	bmaj = bdevsw_lookup_major(&st_bdevsw);
461 	cmaj = cdevsw_lookup_major(&st_cdevsw);
462 
463 	/* kill any pending restart */
464 	callout_stop(&st->sc_callout);
465 
466 	s = splbio();
467 
468 	/* Kill off any queued buffers. */
469 	bufq_drain(&st->buf_queue);
470 
471 	bufq_free(&st->buf_queue);
472 
473 	/* Kill off any pending commands. */
474 	scsipi_kill_pending(st->sc_periph);
475 
476 	splx(s);
477 
478 	/* Nuke the vnodes for any open instances */
479 	mn = STUNIT(self->dv_unit);
480 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
481 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
482 
483 	if (tape_count == 0) {
484 		printf("%s detach: tape_count already zero\n",
485 		       st->sc_dev.dv_xname);
486 	} else {
487 		simple_lock(&tapelist_slock);
488 		TAILQ_REMOVE(&tapelist, st->stats, link);
489 		tape_count--;
490 		simple_unlock(&tapelist_slock);
491 		free(st->stats, M_DEVBUF);
492 	}
493 
494 #if NRND > 0
495 	/* Unhook the entropy source. */
496 	rnd_detach_source(&st->rnd_source);
497 #endif
498 
499 	return (0);
500 }
501 
502 /*
503  * Use the inquiry routine in 'scsi_base' to get drive info so we can
504  * Further tailor our behaviour.
505  */
506 static void
507 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
508 {
509 	const struct st_quirk_inquiry_pattern *finger;
510 	int priority;
511 
512 	finger = scsipi_inqmatch(inqbuf,
513 	    st_quirk_patterns,
514 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
515 	    sizeof(st_quirk_patterns[0]), &priority);
516 	if (priority != 0) {
517 		st->quirkdata = &finger->quirkdata;
518 		st->drive_quirks = finger->quirkdata.quirks;
519 		st->quirks = finger->quirkdata.quirks;	/* start value */
520 		st->page_0_size = finger->quirkdata.page_0_size;
521 		st_loadquirks(st);
522 	}
523 }
524 
525 /*
526  * initialise the subdevices to the default (QUIRK) state.
527  * this will remove any setting made by the system operator or previous
528  * operations.
529  */
530 static void
531 st_loadquirks(struct st_softc *st)
532 {
533 	int i;
534 	const struct	modes *mode;
535 	struct	modes *mode2;
536 
537 	mode = st->quirkdata->modes;
538 	mode2 = st->modes;
539 	for (i = 0; i < 4; i++) {
540 		memset(mode2, 0, sizeof(struct modes));
541 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
542 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
543 		    DENSITY_SET_BY_USER);
544 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
545 			mode2->blksize = mode->blksize;
546 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
547 		}
548 		if (mode->density) {
549 			mode2->density = mode->density;
550 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
551 		}
552 		mode2->quirks |= mode->quirks;
553 		mode++;
554 		mode2++;
555 	}
556 }
557 
558 /*
559  * open the device.
560  */
561 static int
562 stopen(dev_t dev, int flags, int mode, struct proc *p)
563 {
564 	u_int stmode, dsty;
565 	int error, sflags, unit, tries, ntries;
566 	struct st_softc *st;
567 	struct scsipi_periph *periph;
568 	struct scsipi_adapter *adapt;
569 
570 	unit = STUNIT(dev);
571 	if (unit >= st_cd.cd_ndevs)
572 		return (ENXIO);
573 	st = st_cd.cd_devs[unit];
574 	if (st == NULL)
575 		return (ENXIO);
576 
577 	stmode = STMODE(dev);
578 	dsty = STDSTY(dev);
579 
580 	periph = st->sc_periph;
581 	adapt = periph->periph_channel->chan_adapter;
582 
583 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
584 	    unit, st_cd.cd_ndevs));
585 
586 
587 	/*
588 	 * Only allow one at a time
589 	 */
590 	if (periph->periph_flags & PERIPH_OPEN) {
591 		printf("%s: already open\n", st->sc_dev.dv_xname);
592 		return (EBUSY);
593 	}
594 
595 	if ((error = scsipi_adapter_addref(adapt)) != 0)
596 		return (error);
597 
598 	/*
599 	 * clear any latched errors.
600 	 */
601 	st->mt_resid = 0;
602 	st->mt_erreg = 0;
603 	st->asc = 0;
604 	st->ascq = 0;
605 
606 	/*
607 	 * Catch any unit attention errors. Be silent about this
608 	 * unless we're already mounted. We ignore media change
609 	 * if we're in control mode or not mounted yet.
610 	 */
611 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
612 #ifdef SCSIDEBUG
613 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
614 #else
615 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
616 #endif
617 	} else
618 		sflags = 0;
619 
620 	/*
621 	 * If we're already mounted or we aren't configured for
622 	 * a mount delay, only try a test unit ready once. Otherwise,
623 	 * try up to ST_MOUNT_DELAY times with a rest interval of
624 	 * one second between each try.
625 	 */
626 
627 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
628 		ntries = 1;
629 	} else {
630 		ntries = ST_MOUNT_DELAY;
631 	}
632 
633 	for (error = tries = 0; tries < ntries; tries++) {
634 		int slpintr, oflags;
635 
636 		/*
637 		 * If we had no error, or we're opening the control mode
638 		 * device, we jump out right away.
639 		 */
640 
641 		error = scsipi_test_unit_ready(periph, sflags);
642 		if (error == 0 || stmode == CTRL_MODE) {
643 			break;
644 		}
645 
646 		/*
647 		 * We had an error.
648 		 *
649 		 * If we're already mounted or we aren't configured for
650 		 * a mount delay, or the error isn't a NOT READY error,
651 		 * skip to the error exit now.
652 		 */
653 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
654 		    (st->mt_key != SKEY_NOT_READY)) {
655 			goto bad;
656 		}
657 
658 		/*
659 		 * clear any latched errors.
660 		 */
661 		st->mt_resid = 0;
662 		st->mt_erreg = 0;
663 		st->asc = 0;
664 		st->ascq = 0;
665 
666 		/*
667 		 * Fake that we have the device open so
668 		 * we block other apps from getting in.
669 		 */
670 
671 		oflags = periph->periph_flags;
672 		periph->periph_flags |= PERIPH_OPEN;
673 
674 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
675 
676 		periph->periph_flags = oflags;	/* restore flags */
677 		if (slpintr) {
678 			goto bad;
679 		}
680 	}
681 
682 
683 	/*
684 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
685 	 * been opened to set defaults and perform other, usually non-I/O
686 	 * related, operations. In this case, do a quick check to see
687 	 * whether the unit actually had a tape loaded (this will be known
688 	 * as to whether or not we got a NOT READY for the above
689 	 * unit attention). If a tape is there, go do a mount sequence.
690 	 */
691 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
692 		periph->periph_flags |= PERIPH_OPEN;
693 		return (0);
694 	}
695 
696 	/*
697 	 * If we get this far and had an error set, that means we failed
698 	 * to pass the 'test unit ready' test for the non-controlmode device,
699 	 * so we bounce the open.
700 	 */
701 
702 	if (error)
703 		return (error);
704 
705 	/*
706 	 * Else, we're now committed to saying we're open.
707 	 */
708 
709 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
710 
711 	/*
712 	 * If it's a different mode, or if the media has been
713 	 * invalidated, unmount the tape from the previous
714 	 * session but continue with open processing
715 	 */
716 	if (st->last_dsty != dsty ||
717 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
718 		st_unmount(st, NOEJECT);
719 
720 	/*
721 	 * If we are not mounted, then we should start a new
722 	 * mount session.
723 	 */
724 	if (!(st->flags & ST_MOUNTED)) {
725 		if ((error = st_mount_tape(dev, flags)) != 0)
726 			goto bad;
727 		st->last_dsty = dsty;
728 	}
729 	if (!(st->quirks & ST_Q_NOPREVENT)) {
730 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
731 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
732 	}
733 
734 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
735 	return (0);
736 
737 bad:
738 	st_unmount(st, NOEJECT);
739 	scsipi_adapter_delref(adapt);
740 	periph->periph_flags &= ~PERIPH_OPEN;
741 	return (error);
742 }
743 
744 /*
745  * close the device.. only called if we are the LAST
746  * occurence of an open device
747  */
748 static int
749 stclose(dev_t dev, int flags, int mode, struct proc *p)
750 {
751 	int stxx, error = 0;
752 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
753 	struct scsipi_periph *periph = st->sc_periph;
754 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
755 
756 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
757 
758 	/*
759 	 * Make sure that a tape opened in write-only mode will have
760 	 * file marks written on it when closed, even if not written to.
761 	 *
762 	 * This is for SUN compatibility. Actually, the Sun way of
763 	 * things is to:
764 	 *
765 	 *	only write filemarks if there are fmks to be written and
766 	 *   		- open for write (possibly read/write)
767 	 *		- the last operation was a write
768 	 * 	or:
769 	 *		- opened for wronly
770 	 *		- no data was written (including filemarks)
771 	 */
772 
773 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
774 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
775 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
776 		int nm;
777 		error = st_check_eod(st, FALSE, &nm, 0);
778 	}
779 
780 	/*
781 	 * Allow robots to eject tape if needed.
782 	 */
783 	scsipi_prevent(periph, SPAMR_ALLOW,
784 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
785 
786 	switch (STMODE(dev)) {
787 	case NORMAL_MODE:
788 		st_unmount(st, NOEJECT);
789 		break;
790 	case NOREW_MODE:
791 	case CTRL_MODE:
792 		/*
793 		 * Leave mounted unless media seems to have been removed.
794 		 *
795 		 * Otherwise, if we're to terminate a tape with more than one
796 		 * filemark [ and because we're not rewinding here ], backspace
797 		 * one filemark so that later appends will see an unbroken
798 		 * sequence of:
799 		 *
800 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
801 		 */
802 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
803 			st_unmount(st, NOEJECT);
804 		} else if (error == 0) {
805 			/*
806 			 * ST_WRITTEN was preserved from above.
807 			 *
808 			 * All we need to know here is:
809 			 *
810 			 *	Were we writing this tape and was the last
811 			 *	operation a write?
812 			 *
813 			 *	Are there supposed to be 2FM at EOD?
814 			 *
815 			 * If both statements are true, then we backspace
816 			 * one filemark.
817 			 */
818 			stxx |= (st->flags & ST_2FM_AT_EOD);
819 			if ((flags & FWRITE) != 0 &&
820 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
821 				error = st_space(st, -1, SP_FILEMARKS, 0);
822 			}
823 		}
824 		break;
825 	case EJECT_MODE:
826 		st_unmount(st, EJECT);
827 		break;
828 	}
829 
830 	scsipi_wait_drain(periph);
831 
832 	scsipi_adapter_delref(adapt);
833 	periph->periph_flags &= ~PERIPH_OPEN;
834 
835 	return (error);
836 }
837 
838 /*
839  * Start a new mount session.
840  * Copy in all the default parameters from the selected device mode.
841  * and try guess any that seem to be defaulted.
842  */
843 static int
844 st_mount_tape(dev_t dev, int flags)
845 {
846 	int unit;
847 	u_int dsty;
848 	struct st_softc *st;
849 	struct scsipi_periph *periph;
850 	int error = 0;
851 
852 	unit = STUNIT(dev);
853 	dsty = STDSTY(dev);
854 	st = st_cd.cd_devs[unit];
855 	periph = st->sc_periph;
856 
857 	if (st->flags & ST_MOUNTED)
858 		return (0);
859 
860 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
861 	st->flags |= ST_NEW_MOUNT;
862 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
863 	/*
864 	 * If the media is new, then make sure we give it a chance to
865 	 * to do a 'load' instruction.  (We assume it is new.)
866 	 */
867 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
868 		return (error);
869 	/*
870 	 * Throw another dummy instruction to catch
871 	 * 'Unit attention' errors. Many drives give
872 	 * these after doing a Load instruction (with
873 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
874 	 */
875 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
876 
877 	/*
878 	 * Some devices can't tell you much until they have been
879 	 * asked to look at the media. This quirk does this.
880 	 */
881 	if (st->quirks & ST_Q_SENSE_HELP)
882 		if ((error = st_touch_tape(st)) != 0)
883 			return (error);
884 	/*
885 	 * Load the physical device parameters
886 	 * loads: blkmin, blkmax
887 	 */
888 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
889 		return (error);
890 	/*
891 	 * Load the media dependent parameters
892 	 * includes: media_blksize,media_density,numblks
893 	 * As we have a tape in, it should be reflected here.
894 	 * If not you may need the "quirk" above.
895 	 */
896 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
897 		return (error);
898 	/*
899 	 * If we have gained a permanent density from somewhere,
900 	 * then use it in preference to the one supplied by
901 	 * default by the driver.
902 	 */
903 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
904 		st->density = st->modes[dsty].density;
905 	else
906 		st->density = st->media_density;
907 	/*
908 	 * If we have gained a permanent blocksize
909 	 * then use it in preference to the one supplied by
910 	 * default by the driver.
911 	 */
912 	st->flags &= ~ST_FIXEDBLOCKS;
913 	if (st->modeflags[dsty] &
914 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
915 		st->blksize = st->modes[dsty].blksize;
916 		if (st->blksize)
917 			st->flags |= ST_FIXEDBLOCKS;
918 	} else {
919 		if ((error = st_decide_mode(st, FALSE)) != 0)
920 			return (error);
921 	}
922 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
923 		/* ATAPI will return ENODEV for this, and this may be OK */
924 		if (error != ENODEV) {
925 			printf("%s: cannot set selected mode\n",
926 			    st->sc_dev.dv_xname);
927 			return (error);
928 		}
929 	}
930 	st->flags &= ~ST_NEW_MOUNT;
931 	st->flags |= ST_MOUNTED;
932 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
933 	st->blkno = st->fileno = (daddr_t) 0;
934 	return (0);
935 }
936 
937 /*
938  * End the present mount session.
939  * Rewind, and optionally eject the tape.
940  * Reset various flags to indicate that all new
941  * operations require another mount operation
942  */
943 static void
944 st_unmount(struct st_softc *st, boolean eject)
945 {
946 	struct scsipi_periph *periph = st->sc_periph;
947 	int nmarks;
948 
949 	if ((st->flags & ST_MOUNTED) == 0)
950 		return;
951 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
952 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
953 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
954 
955 	/*
956 	 * Section 9.3.3 of the SCSI specs states that a device shall return
957 	 * the density value specified in the last succesfull MODE SELECT
958 	 * after an unload operation, in case it is not able to
959 	 * automatically determine the density of the new medium.
960 	 *
961 	 * So we instruct the device to use the default density, which will
962 	 * prevent the use of stale density values (in particular,
963 	 * in st_touch_tape().
964 	 */
965 	st->density = 0;
966 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
967 		printf("%s: WARNING: cannot revert to default density\n",
968 			st->sc_dev.dv_xname);
969 	}
970 
971 	if (eject) {
972 		if (!(st->quirks & ST_Q_NOPREVENT)) {
973 			scsipi_prevent(periph, SPAMR_ALLOW,
974 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
975 			    XS_CTL_IGNORE_NOT_READY);
976 		}
977 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
978 		st->blkno = st->fileno = (daddr_t) -1;
979 	} else {
980 		st->blkno = st->fileno = (daddr_t) 0;
981 	}
982 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
983 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
984 }
985 
986 /*
987  * Given all we know about the device, media, mode, 'quirks' and
988  * initial operation, make a decision as to how we should be set
989  * to run (regarding blocking and EOD marks)
990  */
991 int
992 st_decide_mode(struct st_softc *st, boolean first_read)
993 {
994 
995 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
996 
997 	/*
998 	 * If the drive can only handle fixed-length blocks and only at
999 	 * one size, perhaps we should just do that.
1000 	 */
1001 	if (st->blkmin && (st->blkmin == st->blkmax)) {
1002 		st->flags |= ST_FIXEDBLOCKS;
1003 		st->blksize = st->blkmin;
1004 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1005 		    ("blkmin == blkmax of %d\n", st->blkmin));
1006 		goto done;
1007 	}
1008 	/*
1009 	 * If the tape density mandates (or even suggests) use of fixed
1010 	 * or variable-length blocks, comply.
1011 	 */
1012 	switch (st->density) {
1013 	case HALFINCH_800:
1014 	case HALFINCH_1600:
1015 	case HALFINCH_6250:
1016 	case DDS:
1017 		st->flags &= ~ST_FIXEDBLOCKS;
1018 		st->blksize = 0;
1019 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1020 		    ("density specified variable\n"));
1021 		goto done;
1022 	case QIC_11:
1023 	case QIC_24:
1024 	case QIC_120:
1025 	case QIC_150:
1026 	case QIC_525:
1027 	case QIC_1320:
1028 	case QIC_3095:
1029 	case QIC_3220:
1030 		st->flags |= ST_FIXEDBLOCKS;
1031 		if (st->media_blksize > 0)
1032 			st->blksize = st->media_blksize;
1033 		else
1034 			st->blksize = DEF_FIXED_BSIZE;
1035 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1036 		    ("density specified fixed\n"));
1037 		goto done;
1038 	}
1039 	/*
1040 	 * If we're about to read the tape, perhaps we should choose
1041 	 * fixed or variable-length blocks and block size according to
1042 	 * what the drive found on the tape.
1043 	 */
1044 	if (first_read &&
1045 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
1046 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
1047 	    (st->media_blksize == 1024))) {
1048 		if (st->media_blksize > 0)
1049 			st->flags |= ST_FIXEDBLOCKS;
1050 		else
1051 			st->flags &= ~ST_FIXEDBLOCKS;
1052 		st->blksize = st->media_blksize;
1053 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1054 		    ("Used media_blksize of %d\n", st->media_blksize));
1055 		goto done;
1056 	}
1057 	/*
1058 	 * We're getting no hints from any direction.  Choose variable-
1059 	 * length blocks arbitrarily.
1060 	 */
1061 	st->flags &= ~ST_FIXEDBLOCKS;
1062 	st->blksize = 0;
1063 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
1064 	    ("Give up and default to variable mode\n"));
1065 
1066 done:
1067 	/*
1068 	 * Decide whether or not to write two file marks to signify end-
1069 	 * of-data.  Make the decision as a function of density.  If
1070 	 * the decision is not to use a second file mark, the SCSI BLANK
1071 	 * CHECK condition code will be recognized as end-of-data when
1072 	 * first read.
1073 	 * (I think this should be a by-product of fixed/variable..julian)
1074 	 */
1075 	switch (st->density) {
1076 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
1077 	case QIC_11:
1078 	case QIC_24:
1079 	case QIC_120:
1080 	case QIC_150:
1081 	case QIC_525:
1082 	case QIC_1320:
1083 	case QIC_3095:
1084 	case QIC_3220:
1085 		st->flags &= ~ST_2FM_AT_EOD;
1086 		break;
1087 	default:
1088 		st->flags |= ST_2FM_AT_EOD;
1089 	}
1090 	return (0);
1091 }
1092 
1093 /*
1094  * Actually translate the requested transfer into
1095  * one the physical driver can understand
1096  * The transfer is described by a buf and will include
1097  * only one physical transfer.
1098  */
1099 static void
1100 ststrategy(struct buf *bp)
1101 {
1102 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
1103 	int s;
1104 
1105 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1106 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
1107 	/*
1108 	 * If it's a null transfer, return immediatly
1109 	 */
1110 	if (bp->b_bcount == 0)
1111 		goto done;
1112 
1113 	/* If offset is negative, error */
1114 	if (bp->b_blkno < 0) {
1115 		bp->b_error = EINVAL;
1116 		goto bad;
1117 	}
1118 
1119 	/*
1120 	 * Odd sized request on fixed drives are verboten
1121 	 */
1122 	if (st->flags & ST_FIXEDBLOCKS) {
1123 		if (bp->b_bcount % st->blksize) {
1124 			printf("%s: bad request, must be multiple of %d\n",
1125 			    st->sc_dev.dv_xname, st->blksize);
1126 			bp->b_error = EIO;
1127 			goto bad;
1128 		}
1129 	}
1130 	/*
1131 	 * as are out-of-range requests on variable drives.
1132 	 */
1133 	else if (bp->b_bcount < st->blkmin ||
1134 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
1135 		printf("%s: bad request, must be between %d and %d\n",
1136 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
1137 		bp->b_error = EIO;
1138 		goto bad;
1139 	}
1140 	s = splbio();
1141 
1142 	/*
1143 	 * Place it in the queue of activities for this tape
1144 	 * at the end (a bit silly because we only have on user..
1145 	 * (but it could fork()))
1146 	 */
1147 	BUFQ_PUT(&st->buf_queue, bp);
1148 
1149 	/*
1150 	 * Tell the device to get going on the transfer if it's
1151 	 * not doing anything, otherwise just wait for completion
1152 	 * (All a bit silly if we're only allowing 1 open but..)
1153 	 */
1154 	ststart(st->sc_periph);
1155 
1156 	splx(s);
1157 	return;
1158 bad:
1159 	bp->b_flags |= B_ERROR;
1160 done:
1161 	/*
1162 	 * Correctly set the buf to indicate a completed xfer
1163 	 */
1164 	bp->b_resid = bp->b_bcount;
1165 	biodone(bp);
1166 	return;
1167 }
1168 
1169 /*
1170  * ststart looks to see if there is a buf waiting for the device
1171  * and that the device is not already busy. If both are true,
1172  * It dequeues the buf and creates a scsi command to perform the
1173  * transfer required. The transfer request will call scsipi_done
1174  * on completion, which will in turn call this routine again
1175  * so that the next queued transfer is performed.
1176  * The bufs are queued by the strategy routine (ststrategy)
1177  *
1178  * This routine is also called after other non-queued requests
1179  * have been made of the scsi driver, to ensure that the queue
1180  * continues to be drained.
1181  * ststart() is called at splbio
1182  */
1183 static void
1184 ststart(struct scsipi_periph *periph)
1185 {
1186 	struct st_softc *st = (void *)periph->periph_dev;
1187 	struct buf *bp;
1188 	struct scsi_rw_tape cmd;
1189 	struct scsipi_xfer *xs;
1190 	int flags, error, s;
1191 
1192 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
1193 	/*
1194 	 * See if there is a buf to do and we are not already
1195 	 * doing one
1196 	 */
1197 	while (periph->periph_active < periph->periph_openings) {
1198 		/* if a special awaits, let it proceed first */
1199 		if (periph->periph_flags & PERIPH_WAITING) {
1200 			periph->periph_flags &= ~PERIPH_WAITING;
1201 			wakeup((caddr_t)periph);
1202 			return;
1203 		}
1204 
1205 		/*
1206 		 * If the device has been unmounted by the user
1207 		 * then throw away all requests until done.
1208 		 */
1209 		if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
1210 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
1211 			if ((bp = BUFQ_GET(&st->buf_queue)) != NULL) {
1212 				/* make sure that one implies the other.. */
1213 				periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
1214 				bp->b_flags |= B_ERROR;
1215 				bp->b_error = EIO;
1216 				bp->b_resid = bp->b_bcount;
1217 				biodone(bp);
1218 				continue;
1219 			} else {
1220 				return;
1221 			}
1222 		}
1223 
1224 		if ((bp = BUFQ_PEEK(&st->buf_queue)) == NULL)
1225 			return;
1226 
1227 		if (st->stats->busy++ == 0) {
1228 			s = splclock();
1229 			st->stats->timestamp = mono_time;
1230 			splx(s);
1231 		}
1232 
1233 		/*
1234 		 * only FIXEDBLOCK devices have pending I/O or space operations.
1235 		 */
1236 		if (st->flags & ST_FIXEDBLOCKS) {
1237 			/*
1238 			 * If we are at a filemark but have not reported it yet
1239 			 * then we should report it now
1240 			 */
1241 			if (st->flags & ST_AT_FILEMARK) {
1242 				if ((bp->b_flags & B_READ) == B_WRITE) {
1243 					/*
1244 					 * Handling of ST_AT_FILEMARK in
1245 					 * st_space will fill in the right file
1246 					 * mark count.
1247 					 * Back up over filemark
1248 					 */
1249 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
1250 						BUFQ_GET(&st->buf_queue);
1251 						bp->b_flags |= B_ERROR;
1252 						bp->b_error = EIO;
1253 						biodone(bp);
1254 						continue;
1255 					}
1256 				} else {
1257 					BUFQ_GET(&st->buf_queue);
1258 					bp->b_resid = bp->b_bcount;
1259 					bp->b_error = 0;
1260 					bp->b_flags &= ~B_ERROR;
1261 					st->flags &= ~ST_AT_FILEMARK;
1262 					biodone(bp);
1263 					continue;	/* seek more work */
1264 				}
1265 			}
1266 		}
1267 		/*
1268 		 * If we are at EOM but have not reported it
1269 		 * yet then we should report it now.
1270 		 */
1271 		if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
1272 			BUFQ_GET(&st->buf_queue);
1273 			bp->b_resid = bp->b_bcount;
1274 			if (st->flags & ST_EIO_PENDING) {
1275 				bp->b_error = EIO;
1276 				bp->b_flags |= B_ERROR;
1277 			}
1278 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
1279 			biodone(bp);
1280 			continue;	/* seek more work */
1281 		}
1282 
1283 		/*
1284 		 * Fill out the scsi command
1285 		 */
1286 		memset(&cmd, 0, sizeof(cmd));
1287 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
1288 		if ((bp->b_flags & B_READ) == B_WRITE) {
1289 			cmd.opcode = WRITE;
1290 			st->flags &= ~ST_FM_WRITTEN;
1291 			flags |= XS_CTL_DATA_OUT;
1292 		} else {
1293 			cmd.opcode = READ;
1294 			flags |= XS_CTL_DATA_IN;
1295 		}
1296 
1297 		/*
1298 		 * Handle "fixed-block-mode" tape drives by using the
1299 		 * block count instead of the length.
1300 		 */
1301 		if (st->flags & ST_FIXEDBLOCKS) {
1302 			cmd.byte2 |= SRW_FIXED;
1303 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
1304 		} else
1305 			_lto3b(bp->b_bcount, cmd.len);
1306 
1307 		/*
1308 		 * Clear 'position updated' indicator
1309 		 */
1310 		st->flags &= ~ST_POSUPDATED;
1311 
1312 		/*
1313 		 * go ask the adapter to do all this for us
1314 		 */
1315 		xs = scsipi_make_xs(periph,
1316 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
1317 		    (u_char *)bp->b_data, bp->b_bcount,
1318 		    0, ST_IO_TIME, bp, flags);
1319 		if (__predict_false(xs == NULL)) {
1320 			/*
1321 			 * out of memory. Keep this buffer in the queue, and
1322 			 * retry later.
1323 			 */
1324 			callout_reset(&st->sc_callout, hz / 2, strestart,
1325 			    periph);
1326 			return;
1327 		}
1328 		/*
1329 		 * need to dequeue the buffer before queuing the command,
1330 		 * because cdstart may be called recursively from the
1331 		 * HBA driver
1332 		 */
1333 #ifdef DIAGNOSTIC
1334 		if (BUFQ_GET(&st->buf_queue) != bp)
1335 			panic("ststart(): dequeued wrong buf");
1336 #else
1337 		BUFQ_GET(&st->buf_queue);
1338 #endif
1339 		error = scsipi_execute_xs(xs);
1340 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
1341 		KASSERT(error == 0);
1342 	} /* go back and see if we can cram more work in.. */
1343 }
1344 
1345 static void
1346 strestart(void *v)
1347 {
1348 	int s = splbio();
1349 	ststart((struct scsipi_periph *)v);
1350 	splx(s);
1351 }
1352 
1353 
1354 static void
1355 stdone(struct scsipi_xfer *xs, int error)
1356 {
1357 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
1358 	struct buf *bp = xs->bp;
1359 	int s;
1360 	struct timeval st_time, diff_time;
1361 
1362 	if (bp) {
1363 		bp->b_error = error;
1364 		bp->b_resid = xs->resid;
1365 		if (error)
1366 			bp->b_flags |= B_ERROR;
1367 
1368 		if ((bp->b_flags & B_READ) == B_WRITE)
1369 			st->flags |= ST_WRITTEN;
1370 		else
1371 			st->flags &= ~ST_WRITTEN;
1372 
1373 		if (st->stats->busy-- == 0) {
1374 			  /* this is not really fatal so we don't panic */
1375 			printf("%s: busy < 0, Oops.\n", st->stats->name);
1376 			st->stats->busy = 0;
1377 		} else {
1378 			s = splclock();
1379 			st_time = mono_time;
1380 			splx(s);
1381 
1382 			timersub(&st_time, &st->stats->timestamp, &diff_time);
1383 			timeradd(&st->stats->time, &diff_time,
1384 				 &st->stats->time);
1385 
1386 			st->stats->timestamp = st_time;
1387 			if (bp->b_bcount > 0) {
1388 				if ((bp->b_flags & B_READ) == B_WRITE) {
1389 					st->stats->wbytes += bp->b_bcount;
1390 					st->stats->wxfer++;
1391 				} else {
1392 					st->stats->rbytes += bp->b_bcount;
1393 					st->stats->rxfer++;
1394 				}
1395 			}
1396 		}
1397 
1398 
1399 #if NRND > 0
1400 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
1401 #endif
1402 
1403 		if ((st->flags & ST_POSUPDATED) == 0) {
1404 			if (error) {
1405 				st->fileno = st->blkno = -1;
1406 			} else if (st->blkno != -1) {
1407 				if (st->flags & ST_FIXEDBLOCKS)
1408 					st->blkno +=
1409 					    (bp->b_bcount / st->blksize);
1410 				else
1411 					st->blkno++;
1412 			}
1413 		}
1414 
1415 		biodone(bp);
1416 	}
1417 }
1418 
1419 static int
1420 stread(dev_t dev, struct uio *uio, int iomode)
1421 {
1422 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1423 
1424 	return (physio(ststrategy, NULL, dev, B_READ,
1425 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1426 }
1427 
1428 static int
1429 stwrite(dev_t dev, struct uio *uio, int iomode)
1430 {
1431 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
1432 
1433 	return (physio(ststrategy, NULL, dev, B_WRITE,
1434 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
1435 }
1436 
1437 /*
1438  * Perform special action on behalf of the user;
1439  * knows about the internals of this device
1440  */
1441 static int
1442 stioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct proc *p)
1443 {
1444 	int error = 0;
1445 	int unit;
1446 	int number, nmarks, dsty;
1447 	int flags;
1448 	struct st_softc *st;
1449 	int hold_blksize;
1450 	u_int8_t hold_density;
1451 	struct mtop *mt = (struct mtop *) arg;
1452 
1453 	/*
1454 	 * Find the device that the user is talking about
1455 	 */
1456 	flags = 0;		/* give error messages, act on errors etc. */
1457 	unit = STUNIT(dev);
1458 	dsty = STDSTY(dev);
1459 	st = st_cd.cd_devs[unit];
1460 	hold_blksize = st->blksize;
1461 	hold_density = st->density;
1462 
1463 	switch ((u_int) cmd) {
1464 
1465 	case MTIOCGET: {
1466 		struct mtget *g = (struct mtget *) arg;
1467 		/*
1468 		 * (to get the current state of READONLY)
1469 		 */
1470 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
1471 		if (error) {
1472 			/*
1473 			 * Ignore the error if in control mode;
1474 			 * this is mandated by st(4).
1475 			 */
1476 			if (STMODE(dev) != CTRL_MODE)
1477 				break;
1478 			error = 0;
1479 		}
1480 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
1481 		memset(g, 0, sizeof(struct mtget));
1482 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
1483 		g->mt_blksiz = st->blksize;
1484 		g->mt_density = st->density;
1485 		g->mt_mblksiz[0] = st->modes[0].blksize;
1486 		g->mt_mblksiz[1] = st->modes[1].blksize;
1487 		g->mt_mblksiz[2] = st->modes[2].blksize;
1488 		g->mt_mblksiz[3] = st->modes[3].blksize;
1489 		g->mt_mdensity[0] = st->modes[0].density;
1490 		g->mt_mdensity[1] = st->modes[1].density;
1491 		g->mt_mdensity[2] = st->modes[2].density;
1492 		g->mt_mdensity[3] = st->modes[3].density;
1493 		g->mt_fileno = st->fileno;
1494 		g->mt_blkno = st->blkno;
1495 		if (st->flags & ST_READONLY)
1496 			g->mt_dsreg |= MT_DS_RDONLY;
1497 		if (st->flags & ST_MOUNTED)
1498 			g->mt_dsreg |= MT_DS_MOUNTED;
1499 		g->mt_resid = st->mt_resid;
1500 		g->mt_erreg = st->mt_erreg;
1501 		/*
1502 		 * clear latched errors.
1503 		 */
1504 		st->mt_resid = 0;
1505 		st->mt_erreg = 0;
1506 		st->asc = 0;
1507 		st->ascq = 0;
1508 		break;
1509 	}
1510 	case MTIOCTOP: {
1511 
1512 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
1513 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
1514 			mt->mt_count));
1515 
1516 		/* compat: in U*x it is a short */
1517 		number = mt->mt_count;
1518 		switch ((short) (mt->mt_op)) {
1519 		case MTWEOF:	/* write an end-of-file record */
1520 			error = st_write_filemarks(st, number, flags);
1521 			break;
1522 		case MTBSF:	/* backward space file */
1523 			number = -number;
1524 		case MTFSF:	/* forward space file */
1525 			error = st_check_eod(st, FALSE, &nmarks, flags);
1526 			if (!error)
1527 				error = st_space(st, number - nmarks,
1528 				    SP_FILEMARKS, flags);
1529 			break;
1530 		case MTBSR:	/* backward space record */
1531 			number = -number;
1532 		case MTFSR:	/* forward space record */
1533 			error = st_check_eod(st, TRUE, &nmarks, flags);
1534 			if (!error)
1535 				error = st_space(st, number, SP_BLKS, flags);
1536 			break;
1537 		case MTREW:	/* rewind */
1538 			error = st_rewind(st, 0, flags);
1539 			break;
1540 		case MTOFFL:	/* rewind and put the drive offline */
1541 			st_unmount(st, EJECT);
1542 			break;
1543 		case MTNOP:	/* no operation, sets status only */
1544 			break;
1545 		case MTRETEN:	/* retension the tape */
1546 			error = st_load(st, LD_RETENSION, flags);
1547 			if (!error)
1548 				error = st_load(st, LD_LOAD, flags);
1549 			break;
1550 		case MTEOM:	/* forward space to end of media */
1551 			error = st_check_eod(st, FALSE, &nmarks, flags);
1552 			if (!error)
1553 				error = st_space(st, 1, SP_EOM, flags);
1554 			break;
1555 		case MTCACHE:	/* enable controller cache */
1556 			st->flags &= ~ST_DONTBUFFER;
1557 			goto try_new_value;
1558 		case MTNOCACHE:	/* disable controller cache */
1559 			st->flags |= ST_DONTBUFFER;
1560 			goto try_new_value;
1561 		case MTERASE:	/* erase volume */
1562 			error = st_erase(st, number, flags);
1563 			break;
1564 		case MTSETBSIZ:	/* Set block size for device */
1565 #ifdef	NOTYET
1566 			if (!(st->flags & ST_NEW_MOUNT)) {
1567 				uprintf("re-mount tape before changing blocksize");
1568 				error = EINVAL;
1569 				break;
1570 			}
1571 #endif
1572 			if (number == 0)
1573 				st->flags &= ~ST_FIXEDBLOCKS;
1574 			else {
1575 				if ((st->blkmin || st->blkmax) &&
1576 				    (number < st->blkmin ||
1577 				    number > st->blkmax)) {
1578 					error = EINVAL;
1579 					break;
1580 				}
1581 				st->flags |= ST_FIXEDBLOCKS;
1582 			}
1583 			st->blksize = number;
1584 			st->flags |= ST_BLOCK_SET;	/*XXX */
1585 			goto try_new_value;
1586 
1587 		case MTSETDNSTY:	/* Set density for device and mode */
1588 			/*
1589 			 * Any number >= 0 and <= 0xff is legal. Numbers
1590 			 * above 0x80 are 'vendor unique'.
1591 			 */
1592 			if (number < 0 || number > 255) {
1593 				error = EINVAL;
1594 				break;
1595 			} else
1596 				st->density = number;
1597 			goto try_new_value;
1598 
1599 		case MTCMPRESS:
1600 			error = st->ops(st, (number == 0) ?
1601 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
1602 			    XS_CTL_SILENT);
1603 			break;
1604 
1605 		case MTEWARN:
1606 			if (number)
1607 				st->flags |= ST_EARLYWARN;
1608 			else
1609 				st->flags &= ~ST_EARLYWARN;
1610 			break;
1611 
1612 		default:
1613 			error = EINVAL;
1614 		}
1615 		break;
1616 	}
1617 	case MTIOCIEOT:
1618 	case MTIOCEEOT:
1619 		break;
1620 
1621 	case MTIOCRDSPOS:
1622 		error = st_rdpos(st, 0, (u_int32_t *) arg);
1623 		break;
1624 
1625 	case MTIOCRDHPOS:
1626 		error = st_rdpos(st, 1, (u_int32_t *) arg);
1627 		break;
1628 
1629 	case MTIOCSLOCATE:
1630 		error = st_setpos(st, 0, (u_int32_t *) arg);
1631 		break;
1632 
1633 	case MTIOCHLOCATE:
1634 		error = st_setpos(st, 1, (u_int32_t *) arg);
1635 		break;
1636 
1637 
1638 	default:
1639 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
1640 					flag, p);
1641 		break;
1642 	}
1643 	return (error);
1644 /*-----------------------------*/
1645 try_new_value:
1646 	/*
1647 	 * Check that the mode being asked for is aggreeable to the
1648 	 * drive. If not, put it back the way it was.
1649 	 *
1650 	 * If in control mode, we can make (persistent) mode changes
1651 	 * even if no medium is loaded (see st(4)).
1652 	 */
1653 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
1654 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
1655 		/* put it back as it was */
1656 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
1657 		st->density = hold_density;
1658 		st->blksize = hold_blksize;
1659 		if (st->blksize)
1660 			st->flags |= ST_FIXEDBLOCKS;
1661 		else
1662 			st->flags &= ~ST_FIXEDBLOCKS;
1663 		return (error);
1664 	}
1665 	/*
1666 	 * As the drive liked it, if we are setting a new default,
1667 	 * set it into the structures as such.
1668 	 *
1669 	 * The means for deciding this are not finalised yet- but
1670 	 * if the device was opened in Control Mode, the values
1671 	 * are persistent now across mounts.
1672 	 */
1673 	if (STMODE(dev) == CTRL_MODE) {
1674 		switch ((short) (mt->mt_op)) {
1675 		case MTSETBSIZ:
1676 			st->modes[dsty].blksize = st->blksize;
1677 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
1678 			break;
1679 		case MTSETDNSTY:
1680 			st->modes[dsty].density = st->density;
1681 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
1682 			break;
1683 		}
1684 	}
1685 	return (0);
1686 }
1687 
1688 /*
1689  * Do a synchronous read.
1690  */
1691 static int
1692 st_read(struct st_softc *st, char *bf, int size, int flags)
1693 {
1694 	struct scsi_rw_tape cmd;
1695 
1696 	/*
1697 	 * If it's a null transfer, return immediatly
1698 	 */
1699 	if (size == 0)
1700 		return (0);
1701 	memset(&cmd, 0, sizeof(cmd));
1702 	cmd.opcode = READ;
1703 	if (st->flags & ST_FIXEDBLOCKS) {
1704 		cmd.byte2 |= SRW_FIXED;
1705 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
1706 		    cmd.len);
1707 	} else
1708 		_lto3b(size, cmd.len);
1709 	return (scsipi_command(st->sc_periph,
1710 	    (void *)&cmd, sizeof(cmd), (void *)bf, size, 0, ST_IO_TIME, NULL,
1711 	    flags | XS_CTL_DATA_IN));
1712 }
1713 
1714 /*
1715  * issue an erase command
1716  */
1717 static int
1718 st_erase(struct st_softc *st, int full, int flags)
1719 {
1720 	int tmo;
1721 	struct scsi_erase cmd;
1722 
1723 	/*
1724 	 * Full erase means set LONG bit in erase command, which asks
1725 	 * the drive to erase the entire unit.  Without this bit, we're
1726 	 * asking the drive to write an erase gap.
1727 	 */
1728 	memset(&cmd, 0, sizeof(cmd));
1729 	cmd.opcode = ERASE;
1730 	if (full) {
1731 		cmd.byte2 = SE_LONG;
1732 		tmo = ST_SPC_TIME;
1733 	} else {
1734 		tmo = ST_IO_TIME;
1735 	}
1736 
1737 	/*
1738 	 * XXX We always do this asynchronously, for now, unless the device
1739 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
1740 	 * want to (eventually) to it synchronously?
1741 	 */
1742 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
1743 		cmd.byte2 |= SE_IMMED;
1744 
1745 	return (scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1746 	    ST_RETRIES, tmo, NULL, flags));
1747 }
1748 
1749 /*
1750  * skip N blocks/filemarks/seq filemarks/eom
1751  */
1752 static int
1753 st_space(struct st_softc *st, int number, u_int what, int flags)
1754 {
1755 	struct scsi_space cmd;
1756 	int error;
1757 
1758 	switch (what) {
1759 	case SP_BLKS:
1760 		if (st->flags & ST_PER_ACTION) {
1761 			if (number > 0) {
1762 				st->flags &= ~ST_PER_ACTION;
1763 				return (EIO);
1764 			} else if (number < 0) {
1765 				if (st->flags & ST_AT_FILEMARK) {
1766 					/*
1767 					 * Handling of ST_AT_FILEMARK
1768 					 * in st_space will fill in the
1769 					 * right file mark count.
1770 					 */
1771 					error = st_space(st, 0, SP_FILEMARKS,
1772 					    flags);
1773 					if (error)
1774 						return (error);
1775 				}
1776 				if (st->flags & ST_BLANK_READ) {
1777 					st->flags &= ~ST_BLANK_READ;
1778 					return (EIO);
1779 				}
1780 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
1781 			}
1782 		}
1783 		break;
1784 	case SP_FILEMARKS:
1785 		if (st->flags & ST_EIO_PENDING) {
1786 			if (number > 0) {
1787 				/* pretend we just discovered the error */
1788 				st->flags &= ~ST_EIO_PENDING;
1789 				return (EIO);
1790 			} else if (number < 0) {
1791 				/* back away from the error */
1792 				st->flags &= ~ST_EIO_PENDING;
1793 			}
1794 		}
1795 		if (st->flags & ST_AT_FILEMARK) {
1796 			st->flags &= ~ST_AT_FILEMARK;
1797 			number--;
1798 		}
1799 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
1800 			/* back away from unwritten tape */
1801 			st->flags &= ~ST_BLANK_READ;
1802 			number++;	/* XXX dubious */
1803 		}
1804 		break;
1805 	case SP_EOM:
1806 		if (st->flags & ST_EOM_PENDING) {
1807 			/* we're already there */
1808 			st->flags &= ~ST_EOM_PENDING;
1809 			return (0);
1810 		}
1811 		if (st->flags & ST_EIO_PENDING) {
1812 			/* pretend we just discovered the error */
1813 			st->flags &= ~ST_EIO_PENDING;
1814 			return (EIO);
1815 		}
1816 		if (st->flags & ST_AT_FILEMARK)
1817 			st->flags &= ~ST_AT_FILEMARK;
1818 		break;
1819 	}
1820 	if (number == 0)
1821 		return (0);
1822 
1823 	memset(&cmd, 0, sizeof(cmd));
1824 	cmd.opcode = SPACE;
1825 	cmd.byte2 = what;
1826 	_lto3b(number, cmd.number);
1827 
1828 	st->flags &= ~ST_POSUPDATED;
1829 	st->last_ctl_resid = 0;
1830 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1831 	    0, ST_SPC_TIME, NULL, flags);
1832 
1833 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
1834 		number = number - st->last_ctl_resid;
1835 		if (what == SP_BLKS) {
1836 			if (st->blkno != -1) {
1837 				st->blkno += number;
1838 			}
1839 		} else if (what == SP_FILEMARKS) {
1840 			if (st->fileno != -1) {
1841 				st->fileno += number;
1842 				if (number > 0) {
1843 					st->blkno = 0;
1844 				} else if (number < 0) {
1845 					st->blkno = -1;
1846 				}
1847 			}
1848 		} else if (what == SP_EOM) {
1849 			/*
1850 			 * This loses us relative position.
1851 			 */
1852 			st->fileno = st->blkno = -1;
1853 		}
1854 	}
1855 	return (error);
1856 }
1857 
1858 /*
1859  * write N filemarks
1860  */
1861 static int
1862 st_write_filemarks(struct st_softc *st, int number, int flags)
1863 {
1864 	int error;
1865 	struct scsi_write_filemarks cmd;
1866 
1867 	/*
1868 	 * It's hard to write a negative number of file marks.
1869 	 * Don't try.
1870 	 */
1871 	if (number < 0)
1872 		return (EINVAL);
1873 	switch (number) {
1874 	case 0:		/* really a command to sync the drive's buffers */
1875 		break;
1876 	case 1:
1877 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
1878 			st->flags &= ~ST_WRITTEN;
1879 		else
1880 			st->flags |= ST_FM_WRITTEN;
1881 		st->flags &= ~ST_PER_ACTION;
1882 		break;
1883 	default:
1884 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
1885 	}
1886 
1887 	memset(&cmd, 0, sizeof(cmd));
1888 	cmd.opcode = WRITE_FILEMARKS;
1889 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1890 		cmd.byte2 = SR_IMMED;
1891 	/*
1892 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
1893 	 * WRITE_FILEMARKS is still used to flush the buffer
1894 	 */
1895 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
1896 		_lto3b(number, cmd.number);
1897 
1898 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
1899 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1900 	    0, ST_IO_TIME * 4, NULL, flags);
1901 	if (error == 0 && st->fileno != -1) {
1902 		st->fileno += number;
1903 	}
1904 	return (error);
1905 }
1906 
1907 /*
1908  * Make sure the right number of file marks is on tape if the
1909  * tape has been written.  If the position argument is true,
1910  * leave the tape positioned where it was originally.
1911  *
1912  * nmarks returns the number of marks to skip (or, if position
1913  * true, which were skipped) to get back original position.
1914  */
1915 static int
1916 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
1917 {
1918 	int error;
1919 
1920 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
1921 	default:
1922 		*nmarks = 0;
1923 		return (0);
1924 	case ST_WRITTEN:
1925 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
1926 		*nmarks = 1;
1927 		break;
1928 	case ST_WRITTEN | ST_2FM_AT_EOD:
1929 		*nmarks = 2;
1930 	}
1931 	error = st_write_filemarks(st, *nmarks, flags);
1932 	if (position && !error)
1933 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
1934 	return (error);
1935 }
1936 
1937 /*
1938  * load/unload/retension
1939  */
1940 static int
1941 st_load(struct st_softc *st, u_int type, int flags)
1942 {
1943 	int error;
1944 	struct scsi_load cmd;
1945 
1946 	if (type != LD_LOAD) {
1947 		int nmarks;
1948 
1949 		error = st_check_eod(st, FALSE, &nmarks, flags);
1950 		if (error) {
1951 			printf("%s: failed to write closing filemarks at "
1952 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
1953 			return (error);
1954 		}
1955 	}
1956 	if (st->quirks & ST_Q_IGNORE_LOADS) {
1957 		if (type == LD_LOAD) {
1958 			/*
1959 			 * If we ignore loads, at least we should try a rewind.
1960 			 */
1961 			return st_rewind(st, 0, flags);
1962 		}
1963 		/* otherwise, we should do what's asked of us */
1964 	}
1965 
1966 	memset(&cmd, 0, sizeof(cmd));
1967 	cmd.opcode = LOAD;
1968 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
1969 		cmd.byte2 = SR_IMMED;
1970 	cmd.how = type;
1971 
1972 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
1973 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
1974 	if (error) {
1975 		printf("%s: error %d in st_load (op %d)\n",
1976 		    st->sc_dev.dv_xname, error, type);
1977 	}
1978 	return (error);
1979 }
1980 
1981 /*
1982  *  Rewind the device
1983  */
1984 static int
1985 st_rewind(struct st_softc *st, u_int immediate, int flags)
1986 {
1987 	struct scsi_rewind cmd;
1988 	int error;
1989 	int nmarks;
1990 
1991 	error = st_check_eod(st, FALSE, &nmarks, flags);
1992 	if (error) {
1993 		printf("%s: failed to write closing filemarks at "
1994 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
1995 		return (error);
1996 	}
1997 	st->flags &= ~ST_PER_ACTION;
1998 
1999 	/*
2000 	 * ATAPI tapes always need immediate to be set
2001 	 */
2002 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
2003 		immediate = SR_IMMED;
2004 
2005 	memset(&cmd, 0, sizeof(cmd));
2006 	cmd.opcode = REWIND;
2007 	cmd.byte2 = immediate;
2008 
2009 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
2010 	    ST_RETRIES, immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
2011 	if (error) {
2012 		printf("%s: error %d trying to rewind\n",
2013 		    st->sc_dev.dv_xname, error);
2014 		/* lost position */
2015 		st->fileno = st->blkno = -1;
2016 	} else {
2017 		st->fileno = st->blkno = 0;
2018 	}
2019 	return (error);
2020 }
2021 
2022 static int
2023 st_rdpos(struct st_softc *st, int hard, u_int32_t *blkptr)
2024 {
2025 	int error;
2026 	u_int8_t posdata[20];
2027 	struct scsi_tape_read_position cmd;
2028 
2029 	/*
2030 	 * We try and flush any buffered writes here if we were writing
2031 	 * and we're trying to get hardware block position. It eats
2032 	 * up performance substantially, but I'm wary of drive firmware.
2033 	 *
2034 	 * I think that *logical* block position is probably okay-
2035 	 * but hardware block position might have to wait for data
2036 	 * to hit media to be valid. Caveat Emptor.
2037 	 */
2038 
2039 	if (hard && (st->flags & ST_WRITTEN)) {
2040 		/*
2041 		 * First flush any pending writes...
2042 		 */
2043 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
2044 		/*
2045 		 * The latter case is for 'write protected' tapes
2046 		 * which are too stupid to recognize a zero count
2047 		 * for writing filemarks as a no-op.
2048 		 */
2049 		if (error != 0 && error != EACCES && error != EROFS)
2050 			return (error);
2051 	}
2052 
2053 	memset(&cmd, 0, sizeof(cmd));
2054 	memset(&posdata, 0, sizeof(posdata));
2055 	cmd.opcode = READ_POSITION;
2056 	if (hard)
2057 		cmd.byte1 = 1;
2058 
2059 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
2060 	    (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
2061 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
2062 
2063 	if (error == 0) {
2064 #if	0
2065 		printf("posdata:");
2066 		for (hard = 0; hard < sizeof(posdata); hard++)
2067 			printf("%02x ", posdata[hard] & 0xff);
2068 		printf("\n");
2069 #endif
2070 		if (posdata[0] & 0x4)	/* Block Position Unknown */
2071 			error = EINVAL;
2072 		else
2073 			*blkptr = _4btol(&posdata[4]);
2074 	}
2075 	return (error);
2076 }
2077 
2078 static int
2079 st_setpos(struct st_softc *st, int hard, u_int32_t *blkptr)
2080 {
2081 	int error;
2082 	struct scsi_tape_locate cmd;
2083 
2084 	/*
2085 	 * We used to try and flush any buffered writes here.
2086 	 * Now we push this onto user applications to either
2087 	 * flush the pending writes themselves (via a zero count
2088 	 * WRITE FILEMARKS command) or they can trust their tape
2089 	 * drive to do this correctly for them.
2090 	 *
2091 	 * There are very ugly performance limitations otherwise.
2092 	 */
2093 
2094 	memset(&cmd, 0, sizeof(cmd));
2095 	cmd.opcode = LOCATE;
2096 	if (hard)
2097 		cmd.byte2 = 1 << 2;
2098 	_lto4b(*blkptr, cmd.blkaddr);
2099 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
2100 	    ST_RETRIES, ST_SPC_TIME, NULL, 0);
2101 	/*
2102 	 * Note file && block number position now unknown (if
2103 	 * these things ever start being maintained in this driver)
2104 	 */
2105 	st->fileno = st->blkno = -1;
2106 	return (error);
2107 }
2108 
2109 
2110 /*
2111  * Look at the returned sense and act on the error and determine
2112  * the unix error number to pass back..., 0 (== report no error),
2113  * -1 = retry the operation, -2 continue error processing.
2114  */
2115 static int
2116 st_interpret_sense(struct scsipi_xfer *xs)
2117 {
2118 	struct scsipi_periph *periph = xs->xs_periph;
2119 	struct scsi_sense_data *sense = &xs->sense.scsi_sense;
2120 	struct buf *bp = xs->bp;
2121 	struct st_softc *st = (void *)periph->periph_dev;
2122 	int retval = EJUSTRETURN;
2123 	int doprint = ((xs->xs_control & XS_CTL_SILENT) == 0);
2124 	u_int8_t key;
2125 	int32_t info;
2126 
2127 	/*
2128 	 * If it isn't a extended or extended/deferred error, let
2129 	 * the generic code handle it.
2130 	 */
2131 	if (SSD_RCODE(sense->response_code) != SSD_RCODE_CURRENT &&
2132 	    SSD_RCODE(sense->response_code) != SSD_RCODE_DEFERRED)
2133 		return (retval);
2134 
2135 	if (sense->response_code & SSD_RCODE_VALID)
2136 		info = _4btol(sense->info);
2137 	else
2138 		info = (st->flags & ST_FIXEDBLOCKS) ?
2139 		    xs->datalen / st->blksize : xs->datalen;
2140 	key = SSD_SENSE_KEY(sense->flags);
2141 	st->mt_erreg = key;
2142 	st->asc = sense->asc;
2143 	st->ascq = sense->ascq;
2144 	st->mt_resid = (short) info;
2145 
2146 	if (key == SKEY_NOT_READY && st->asc == 0x4 && st->ascq == 0x1) {
2147 		/* Not Ready, Logical Unit Is in Process Of Becoming Ready */
2148 		if (!callout_pending(&periph->periph_callout))
2149 			scsipi_periph_freeze(periph, 1);
2150 		callout_reset(&periph->periph_callout,
2151 		    hz, scsipi_periph_timed_thaw, periph);
2152 		return (ERESTART);
2153 	}
2154 
2155 	/*
2156 	 * If the device is not open yet, let generic handle
2157 	 */
2158 	if ((periph->periph_flags & PERIPH_OPEN) == 0) {
2159 		return (retval);
2160 	}
2161 
2162 	xs->resid = info;
2163 	if (st->flags & ST_FIXEDBLOCKS) {
2164 		if (bp) {
2165 			xs->resid *= st->blksize;
2166 			st->last_io_resid = xs->resid;
2167 		} else {
2168 			st->last_ctl_resid = xs->resid;
2169 		}
2170 		if (key == SKEY_VOLUME_OVERFLOW) {
2171 			st->flags |= ST_EIO_PENDING;
2172 			if (bp)
2173 				bp->b_resid = xs->resid;
2174 		} else if (sense->flags & SSD_EOM) {
2175 			if ((st->flags & ST_EARLYWARN) == 0)
2176 				st->flags |= ST_EIO_PENDING;
2177 			st->flags |= ST_EOM_PENDING;
2178 			if (bp) {
2179 #if 0
2180 				bp->b_resid = xs->resid;
2181 #else
2182 				/*
2183 				 * Grotesque as it seems, the few times
2184 				 * I've actually seen a non-zero resid,
2185 				 * the tape drive actually lied and had
2186 				 * written all the data!
2187 				 */
2188 				bp->b_resid = 0;
2189 #endif
2190 			}
2191 		}
2192 		if (sense->flags & SSD_FILEMARK) {
2193 			st->flags |= ST_AT_FILEMARK;
2194 			if (bp)
2195 				bp->b_resid = xs->resid;
2196 			if (st->fileno != (daddr_t) -1) {
2197 				st->fileno++;
2198 				st->blkno = 0;
2199 				st->flags |= ST_POSUPDATED;
2200 			}
2201 		}
2202 		if (sense->flags & SSD_ILI) {
2203 			st->flags |= ST_EIO_PENDING;
2204 			if (bp)
2205 				bp->b_resid = xs->resid;
2206 			if (sense->response_code & SSD_RCODE_VALID &&
2207 			    (xs->xs_control & XS_CTL_SILENT) == 0)
2208 				printf("%s: block wrong size, %d blocks "
2209 				    "residual\n", st->sc_dev.dv_xname, info);
2210 
2211 			/*
2212 			 * This quirk code helps the drive read
2213 			 * the first tape block, regardless of
2214 			 * format.  That is required for these
2215 			 * drives to return proper MODE SENSE
2216 			 * information.
2217 			 */
2218 			if ((st->quirks & ST_Q_SENSE_HELP) &&
2219 			    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
2220 				st->blksize -= 512;
2221 			else if ((st->flags & ST_POSUPDATED) == 0) {
2222 				if (st->blkno != (daddr_t) -1) {
2223 					st->blkno +=
2224 					    (xs->datalen / st->blksize);
2225 					st->flags |= ST_POSUPDATED;
2226 				}
2227 			}
2228 		}
2229 		/*
2230 		 * If data wanted and no data was transferred, do it immediately
2231 		 */
2232 		if (xs->datalen && xs->resid >= xs->datalen) {
2233 			if (st->flags & ST_EIO_PENDING)
2234 				return (EIO);
2235 			if (st->flags & ST_AT_FILEMARK) {
2236 				if (bp)
2237 					bp->b_resid = xs->resid;
2238 				return (0);
2239 			}
2240 		}
2241 	} else {		/* must be variable mode */
2242 		if (bp) {
2243 			st->last_io_resid = xs->resid;
2244 		} else {
2245 			st->last_ctl_resid = xs->resid;
2246 		}
2247 		if (sense->flags & SSD_EOM) {
2248 			/*
2249 			 * The current semantics of this
2250 			 * driver requires EOM detection
2251 			 * to return EIO unless early
2252 			 * warning detection is enabled
2253 			 * for variable mode (this is always
2254 			 * on for fixed block mode).
2255 			 */
2256 			if (st->flags & ST_EARLYWARN) {
2257 				st->flags |= ST_EOM_PENDING;
2258 				retval = 0;
2259 			} else {
2260 				retval = EIO;
2261 			}
2262 
2263 			/*
2264 			 * If it's an unadorned EOM detection,
2265 			 * suppress printing an error.
2266 			 */
2267 			if (key == SKEY_NO_SENSE) {
2268 				doprint = 0;
2269 			}
2270 		} else if (sense->flags & SSD_FILEMARK) {
2271 			retval = 0;
2272 			if (st->fileno != (daddr_t) -1) {
2273 				st->fileno++;
2274 				st->blkno = 0;
2275 				st->flags |= ST_POSUPDATED;
2276 			}
2277 		} else if (sense->flags & SSD_ILI) {
2278 			if (info < 0) {
2279 				/*
2280 				 * The tape record was bigger than the read
2281 				 * we issued.
2282 				 */
2283 				if ((xs->xs_control & XS_CTL_SILENT) == 0) {
2284 					printf("%s: %d-byte tape record too big"
2285 					    " for %d-byte user buffer\n",
2286 					    st->sc_dev.dv_xname,
2287 					    xs->datalen - info, xs->datalen);
2288 				}
2289 				retval = EIO;
2290 			} else {
2291 				retval = 0;
2292 				if (st->blkno != (daddr_t) -1) {
2293 					st->blkno++;
2294 					st->flags |= ST_POSUPDATED;
2295 				}
2296 			}
2297 		}
2298 		if (bp)
2299 			bp->b_resid = info;
2300 	}
2301 
2302 #ifndef SCSIPI_DEBUG
2303 	if (retval == 0 && key == SKEY_NO_SENSE)
2304 		doprint = 0;
2305 #endif
2306 	if (key == SKEY_BLANK_CHECK) {
2307 		/*
2308 		 * This quirk code helps the drive read the
2309 		 * first tape block, regardless of format.  That
2310 		 * is required for these drives to return proper
2311 		 * MODE SENSE information.
2312 		 */
2313 		if ((st->quirks & ST_Q_SENSE_HELP) &&
2314 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
2315 			/* still starting */
2316 			st->blksize -= 512;
2317 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
2318 			st->flags |= ST_BLANK_READ;
2319 			xs->resid = xs->datalen;
2320 			if (bp) {
2321 				bp->b_resid = xs->resid;
2322 				/* return an EOF */
2323 			}
2324 			retval = 0;
2325 			/* lost position */
2326 			st->fileno = st->blkno = -1;
2327 		}
2328 	}
2329 
2330 	/*
2331 	 * If generic sense processing will continue, we should not
2332 	 * print sense info here.
2333 	 */
2334 	if (retval == EJUSTRETURN)
2335 		doprint = 0;
2336 
2337 	if (doprint) {
2338 #ifdef	SCSIVERBOSE
2339 		scsipi_print_sense(xs, 0);
2340 #else
2341 		scsipi_printaddr(periph);
2342 		printf("Sense Key 0x%02x", key);
2343 		if ((sense->response_code & SSD_RCODE_VALID) != 0) {
2344 			switch (key) {
2345 			case SKEY_NOT_READY:
2346 			case SKEY_ILLEGAL_REQUEST:
2347 			case SKEY_UNIT_ATTENTION:
2348 			case SKEY_DATA_PROTECT:
2349 				break;
2350 			case SKEY_VOLUME_OVERFLOW:
2351 			case SKEY_BLANK_CHECK:
2352 				printf(", requested size: %d (decimal)", info);
2353 				break;
2354 			case SKEY_ABORTED_COMMAND:
2355 				if (xs->xs_retries)
2356 					printf(", retrying");
2357 				printf(", cmd 0x%x, info 0x%x",
2358 				    xs->cmd->opcode, info);
2359 				break;
2360 			default:
2361 				printf(", info = %d (decimal)", info);
2362 			}
2363 		}
2364 		if (sense->extra_len != 0) {
2365 			int n;
2366 			printf(", data =");
2367 			for (n = 0; n < sense->extra_len; n++)
2368 				printf(" %02x", sense->csi[n]);
2369 		}
2370 		printf("\n");
2371 #endif
2372 	}
2373 	return (retval);
2374 }
2375 
2376 /*
2377  * The quirk here is that the drive returns some value to st_mode_sense
2378  * incorrectly until the tape has actually passed by the head.
2379  *
2380  * The method is to set the drive to large fixed-block state (user-specified
2381  * density and 1024-byte blocks), then read and rewind to get it to sense the
2382  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
2383  * work, as a last resort, try variable- length blocks.  The result will be
2384  * the ability to do an accurate st_mode_sense.
2385  *
2386  * We know we can do a rewind because we just did a load, which implies rewind.
2387  * Rewind seems preferable to space backward if we have a virgin tape.
2388  *
2389  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
2390  * error processing, both part of st_interpret_sense.
2391  */
2392 static int
2393 st_touch_tape(struct st_softc *st)
2394 {
2395 	char *bf;
2396 	int readsize;
2397 	int error;
2398 
2399 	bf = malloc(1024, M_TEMP, M_NOWAIT);
2400 	if (bf == NULL)
2401 		return (ENOMEM);
2402 
2403 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
2404 		goto bad;
2405 
2406 	/*
2407 	 * If the block size is already known from the
2408 	 * sense data, use it. Else start probing at 1024.
2409 	 */
2410 	if (st->media_blksize > 0)
2411 		st->blksize = st->media_blksize;
2412 	else
2413 		st->blksize = 1024;
2414 
2415 	do {
2416 		switch (st->blksize) {
2417 		case 512:
2418 		case 1024:
2419 			readsize = st->blksize;
2420 			st->flags |= ST_FIXEDBLOCKS;
2421 			break;
2422 		default:
2423 			readsize = 1;
2424 			st->flags &= ~ST_FIXEDBLOCKS;
2425 		}
2426 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
2427 		    != 0) {
2428 			/*
2429 			 * The device did not agree with the proposed
2430 			 * block size. If we exhausted our options,
2431 			 * return failure, else try another.
2432 			 */
2433 			if (readsize == 1)
2434 				goto bad;
2435 			st->blksize -= 512;
2436 			continue;
2437 		}
2438 		st_read(st, bf, readsize, XS_CTL_SILENT);	/* XXX */
2439 		if ((error = st_rewind(st, 0, 0)) != 0) {
2440 bad:			free(bf, M_TEMP);
2441 			return (error);
2442 		}
2443 	} while (readsize != 1 && readsize > st->blksize);
2444 
2445 	free(bf, M_TEMP);
2446 	return (0);
2447 }
2448 
2449 static int
2450 stdump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
2451 {
2452 
2453 	/* Not implemented. */
2454 	return (ENXIO);
2455 }
2456 
2457 int
2458 sysctl_hw_tapenames(SYSCTLFN_ARGS)
2459 {
2460 	char bf[TAPENAMELEN + 1];
2461 	char *where = oldp;
2462 	struct tape *tapep;
2463 	size_t needed, left, slen;
2464 	int error, first;
2465 
2466 	if (newp != NULL)
2467 		return (EPERM);
2468 	if (namelen != 0)
2469 		return (EINVAL);
2470 
2471 	first = 1;
2472 	error = 0;
2473 	needed = 0;
2474 	left = *oldlenp;
2475 
2476 	simple_lock(&tapelist_slock);
2477 	for (tapep = TAILQ_FIRST(&tapelist); tapep != NULL;
2478 	    tapep = TAILQ_NEXT(tapep, link)) {
2479 		if (where == NULL)
2480 			needed += strlen(tapep->name) + 1;
2481 		else {
2482 			memset(bf, 0, sizeof(bf));
2483 			if (first) {
2484 				strncpy(bf, tapep->name, sizeof(bf));
2485 				first = 0;
2486 			} else {
2487 				bf[0] = ' ';
2488 				strncpy(bf + 1, tapep->name, sizeof(bf) - 1);
2489 			}
2490 			bf[TAPENAMELEN] = '\0';
2491 			slen = strlen(bf);
2492 			if (left < slen + 1)
2493 				break;
2494 			/* +1 to copy out the trailing NUL byte */
2495 			error = copyout(bf, where, slen + 1);
2496 			if (error)
2497 				break;
2498 			where += slen;
2499 			needed += slen;
2500 			left -= slen;
2501 		}
2502 	}
2503 	simple_unlock(&tapelist_slock);
2504 	*oldlenp = needed;
2505 	return (error);
2506 }
2507 
2508 int
2509 sysctl_hw_tapestats(SYSCTLFN_ARGS)
2510 {
2511 	struct tape_sysctl stape;
2512 	struct tape *tapep;
2513 	char *where = oldp;
2514 	size_t tocopy, left;
2515 	int error;
2516 
2517 	if (newp != NULL)
2518 		return (EPERM);
2519 
2520 	tocopy = name[0];
2521 
2522 	if (where == NULL) {
2523 		*oldlenp = tape_count * tocopy;
2524 		return (0);
2525 	}
2526 
2527 	error = 0;
2528 	left = *oldlenp;
2529 	memset(&stape, 0, sizeof(stape));
2530 	*oldlenp = 0;
2531 
2532 	simple_lock(&tapelist_slock);
2533 	TAILQ_FOREACH(tapep, &tapelist, link) {
2534 		if (left < tocopy)
2535 			break;
2536 		strncpy(stape.name, tapep->name, sizeof(stape.name));
2537 		stape.xfer = tapep->rxfer + tapep->wxfer;
2538 		stape.rxfer = tapep->rxfer;
2539 		stape.wxfer = tapep->wxfer;
2540 		stape.bytes = tapep->rbytes + tapep->wbytes;
2541 		stape.rbytes = tapep->rbytes;
2542 		stape.wbytes = tapep->wbytes;
2543 		stape.attachtime_sec = tapep->attachtime.tv_sec;
2544 		stape.attachtime_usec = tapep->attachtime.tv_usec;
2545 		stape.timestamp_sec = tapep->timestamp.tv_sec;
2546 		stape.timestamp_usec = tapep->timestamp.tv_usec;
2547 		stape.time_sec = tapep->time.tv_sec;
2548 		stape.time_usec = tapep->time.tv_usec;
2549 		stape.busy = tapep->busy;
2550 
2551 		error = copyout(&stape, where, min(tocopy, sizeof(stape)));
2552 		if (error)
2553 			break;
2554 		where += tocopy;
2555 		*oldlenp += tocopy;
2556 		left -= tocopy;
2557 	}
2558 	simple_unlock(&tapelist_slock);
2559 	return (error);
2560 }
2561 
2562 struct tape *
2563 drive_attach(char *name)
2564 {
2565 	struct tape *stats;
2566 	int s;
2567 
2568 	/* Allocate and initialise statistics */
2569 	stats = (struct tape *) malloc(sizeof(struct tape), M_DEVBUF,
2570 					   M_WAITOK);
2571 	stats->rxfer = stats->wxfer = stats->rbytes = 0;
2572 	stats->wbytes = stats->busy = 0;
2573 
2574 	/*
2575 	 * Set the attached timestamp.
2576 	 */
2577 	s = splclock();
2578 	stats->attachtime = mono_time;
2579 	splx(s);
2580 
2581 	  /* and clear the utilisation time */
2582 	timerclear(&stats->time);
2583 
2584 	  /* link the tape drive to the tapelist */
2585 	simple_lock(&tapelist_slock);
2586 	TAILQ_INSERT_TAIL(&tapelist, stats, link);
2587 	tape_count++;
2588 	simple_unlock(&tapelist_slock);
2589 	stats->name = name;
2590 
2591 	return stats;
2592 }
2593 
2594 SYSCTL_SETUP(sysctl_tape_stats_setup, "sysctl tape stats setup")
2595 {
2596 	sysctl_createv(clog, 0, NULL, NULL,
2597 		       CTLFLAG_PERMANENT,
2598 		       CTLTYPE_STRING, "tapenames",
2599 		       SYSCTL_DESCR("List of tape devices present"),
2600 		       sysctl_hw_tapenames, 0, NULL, 0,
2601 		       CTL_HW, HW_TAPENAMES, CTL_EOL);
2602 	sysctl_createv(clog, 0, NULL, NULL,
2603 		       CTLFLAG_PERMANENT,
2604 		       CTLTYPE_STRUCT, "tapestats",
2605 		       SYSCTL_DESCR("Statistics on tape drive operation"),
2606 		       sysctl_hw_tapestats, 0, NULL, 0,
2607 		       CTL_HW, HW_TAPESTATS, CTL_EOL);
2608 }
2609