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st.c revision 1.181
      1 /*	$NetBSD: st.c,v 1.181 2005/05/29 22:00:50 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 (at) 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 (at) tfs.com) Sept 1992
     54  * major changes by Julian Elischer (julian (at) jules.dialix.oz.au) May 1993
     55  *
     56  * A lot of rewhacking done by mjacob (mjacob (at) nas.nasa.gov).
     57  */
     58 
     59 #include <sys/cdefs.h>
     60 __KERNEL_RCSID(0, "$NetBSD: st.c,v 1.181 2005/05/29 22:00:50 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 
     80 #include <dev/scsipi/scsi_spc.h>
     81 #include <dev/scsipi/scsipi_all.h>
     82 #include <dev/scsipi/scsi_all.h>
     83 #include <dev/scsipi/scsi_tape.h>
     84 #include <dev/scsipi/scsipiconf.h>
     85 #include <dev/scsipi/scsipi_base.h>
     86 #include <dev/scsipi/stvar.h>
     87 
     88 /* Defines for device specific stuff */
     89 #define DEF_FIXED_BSIZE  512
     90 
     91 #define STMODE(z)	( minor(z)       & 0x03)
     92 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
     93 #define STUNIT(z)	((minor(z) >> 4)       )
     94 #define STNMINOR	16
     95 
     96 #define NORMAL_MODE	0
     97 #define NOREW_MODE	1
     98 #define EJECT_MODE	2
     99 #define CTRL_MODE	3
    100 
    101 #define	FALSE		0
    102 #define	TRUE		1
    103 
    104 #ifndef		ST_MOUNT_DELAY
    105 #define		ST_MOUNT_DELAY		0
    106 #endif
    107 
    108 static dev_type_open(stopen);
    109 static dev_type_close(stclose);
    110 static dev_type_read(stread);
    111 static dev_type_write(stwrite);
    112 static dev_type_ioctl(stioctl);
    113 static dev_type_strategy(ststrategy);
    114 static dev_type_dump(stdump);
    115 
    116 const struct bdevsw st_bdevsw = {
    117 	stopen, stclose, ststrategy, stioctl, stdump, nosize, D_TAPE
    118 };
    119 
    120 const struct cdevsw st_cdevsw = {
    121 	stopen, stclose, stread, stwrite, stioctl,
    122 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
    123 };
    124 
    125 /*
    126  * Define various devices that we know mis-behave in some way,
    127  * and note how they are bad, so we can correct for them
    128  */
    129 
    130 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
    131 	{{T_SEQUENTIAL, T_REMOV,
    132 	 "        ", "                ", "    "}, {0, 0, {
    133 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    134 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
    135 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
    136 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
    137 	}}},
    138 	{{T_SEQUENTIAL, T_REMOV,
    139 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
    140 		{0, 0, 0},				/* minor 0-3 */
    141 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
    142 		{0, 0, QIC_150},			/* minor 8-11 */
    143 		{0, 0, QIC_120}				/* minor 12-15 */
    144 	}}},
    145  	{{T_SEQUENTIAL, T_REMOV,
    146  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
    147 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    148 		{0, 0, QIC_525},			/* minor 4-7 */
    149 		{0, 0, QIC_150},			/* minor 8-11 */
    150 		{0, 0, QIC_120}				/* minor 12-15 */
    151 	}}},
    152 	{{T_SEQUENTIAL, T_REMOV,
    153 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
    154 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
    155 		{0, 0, 0},				/* minor 4-7 */
    156 		{0, 0, 0},				/* minor 8-11 */
    157 		{0, 0, 0}				/* minor 12-15 */
    158 	}}},
    159 	/*
    160 	 * lacking a manual for the 4200, it's not clear what the
    161 	 * specific density codes should be- the device is a 2.5GB
    162 	 * capable QIC drive, those density codes aren't readily
    163 	 * availabel. The 'default' will just have to do.
    164 	 */
    165  	{{T_SEQUENTIAL, T_REMOV,
    166  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
    167 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    168 		{0, 0, QIC_525},			/* minor 4-7 */
    169 		{0, 0, QIC_150},			/* minor 8-11 */
    170 		{0, 0, QIC_120}				/* minor 12-15 */
    171 	}}},
    172 	/*
    173 	 * At least -005 and -007 need this.  I'll assume they all do unless I
    174 	 * hear otherwise.  - mycroft, 31MAR1994
    175 	 */
    176 	{{T_SEQUENTIAL, T_REMOV,
    177 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
    178 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    179 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
    180 		{0, 0, QIC_150},			/* minor 8-11 */
    181 		{0, 0, QIC_120}				/* minor 12-15 */
    182 	}}},
    183 	/*
    184 	 * One user reports that this works for his tape drive.  It probably
    185 	 * needs more work.  - mycroft, 09APR1994
    186 	 */
    187 	{{T_SEQUENTIAL, T_REMOV,
    188 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
    189 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    190 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
    191 		{0, 0, QIC_150},			/* minor 8-11 */
    192 		{0, 0, QIC_120}				/* minor 12-15 */
    193 	}}},
    194 	{{T_SEQUENTIAL, T_REMOV,
    195 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
    196 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    197 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
    198 		{0, 0, QIC_150},			/* minor 8-11 */
    199 		{0, 0, QIC_120}				/* minor 12-15 */
    200 	}}},
    201 	{{T_SEQUENTIAL, T_REMOV,
    202 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
    203 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    204 		{0, 0, QIC_150},			/* minor 4-7 */
    205 		{0, 0, QIC_120},			/* minor 8-11 */
    206 		{0, 0, QIC_24}				/* minor 12-15 */
    207 	}}},
    208 	{{T_SEQUENTIAL, T_REMOV,
    209 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
    210 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    211 		{0, 0, QIC_150},			/* minor 4-7 */
    212 		{0, 0, QIC_120},			/* minor 8-11 */
    213 		{0, 0, QIC_24}				/* minor 12-15 */
    214 	}}},
    215 	{{T_SEQUENTIAL, T_REMOV,
    216 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
    217 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    218 		{0, 0, QIC_11},				/* minor 4-7 */
    219 		{0, 0, QIC_24},				/* minor 8-11 */
    220 		{0, 0, QIC_24}				/* minor 12-15 */
    221 	}}},
    222 	{{T_SEQUENTIAL, T_REMOV,
    223 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
    224 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    225 		{0, 0, QIC_24},				/* minor 4-7 */
    226 		{0, 0, QIC_120},			/* minor 8-11 */
    227 		{0, 0, QIC_150}				/* minor 12-15 */
    228 	}}},
    229 	{{T_SEQUENTIAL, T_REMOV,
    230 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
    231 		{0, 0, 0},				/* minor 0-3 */
    232 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
    233 		{0, 0, QIC_150},			/* minor 8-11 */
    234 		{0, 0, QIC_120}				/* minor 12-15 */
    235 	}}},
    236 	{{T_SEQUENTIAL, T_REMOV,
    237 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
    238 		{0, 0, 0},				/* minor 0-3 */
    239 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
    240 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
    241 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
    242 	}}},
    243 	{{T_SEQUENTIAL, T_REMOV,
    244 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
    245 		{0, 0, 0},				/* minor 0-3 */
    246 		{0, 0, 0},				/* minor 4-7 */
    247 		{0, 0, 0},				/* minor 8-11 */
    248 		{0, 0, 0}				/* minor 12-15 */
    249 	}}},
    250 	{{T_SEQUENTIAL, T_REMOV,
    251 	 "STK",      "9490",             ""},
    252 				{ST_Q_FORCE_BLKSIZE, 0, {
    253 		{0, 0, 0},				/* minor 0-3 */
    254 		{0, 0, 0},				/* minor 4-7 */
    255 		{0, 0, 0},				/* minor 8-11 */
    256 		{0, 0, 0}				/* minor 12-15 */
    257 	}}},
    258 	{{T_SEQUENTIAL, T_REMOV,
    259 	 "STK",      "SD-3",             ""},
    260 				{ST_Q_FORCE_BLKSIZE, 0, {
    261 		{0, 0, 0},				/* minor 0-3 */
    262 		{0, 0, 0},				/* minor 4-7 */
    263 		{0, 0, 0},				/* minor 8-11 */
    264 		{0, 0, 0}				/* minor 12-15 */
    265 	}}},
    266 	{{T_SEQUENTIAL, T_REMOV,
    267 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
    268 		{0, 0, 0},				/* minor 0-3 */
    269 		{0, 0, 0},				/* minor 4-7 */
    270 		{0, 0, 0},				/* minor 8-11 */
    271 		{0, 0, 0}				/* minor 12-15 */
    272 	}}},
    273 	{{T_SEQUENTIAL, T_REMOV,
    274 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
    275 		{0, 0, QIC_3095},			/* minor 0-3 */
    276 		{0, 0, QIC_3095},			/* minor 4-7 */
    277 		{0, 0, QIC_3095},			/* minor 8-11 */
    278 		{0, 0, QIC_3095},			/* minor 12-15 */
    279 	}}},
    280 #if 0
    281 	{{T_SEQUENTIAL, T_REMOV,
    282 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
    283 		{0, 0, 0},				/* minor 0-3 */
    284 		{0, 0, 0},				/* minor 4-7 */
    285 		{0, 0, 0},				/* minor 8-11 */
    286 		{0, 0, 0}				/* minor 12-15 */
    287 	}}},
    288 #endif
    289 	{{T_SEQUENTIAL, T_REMOV,
    290 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
    291 		{0, 0, 0},			        /* minor 0-3 */
    292 		{0, 0, 0},			        /* minor 4-7 */
    293 		{0, 0, 0},			        /* minor 8-11 */
    294 		{0, 0, 0}			        /* minor 12-15 */
    295 	}}},
    296 	{{T_SEQUENTIAL, T_REMOV,
    297 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
    298 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
    299 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
    300 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
    301 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
    302 	}}},
    303 	{{T_SEQUENTIAL, T_REMOV,
    304 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
    305 		{0, 0, 0},                              /* minor 0-3 */
    306 		{0, 0, 0},                              /* minor 4-7 */
    307 		{0, 0, 0},                              /* minor 8-11 */
    308 		{0, 0, 0}                               /* minor 12-15 */
    309 	}}},
    310 	{{T_SEQUENTIAL, T_REMOV,
    311 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
    312 		{0, 0, 0},			       /* minor 0-3 */
    313 		{0, 0, 0},			       /* minor 4-7 */
    314 		{0, 0, 0},			       /* minor 8-11 */
    315 		{0, 0, 0}			       /* minor 12-15 */
    316 	}}},
    317 };
    318 
    319 #define NOEJECT 0
    320 #define EJECT 1
    321 
    322 static void	st_identify_drive(struct st_softc *,
    323 		    struct scsipi_inquiry_pattern *);
    324 static void	st_loadquirks(struct st_softc *);
    325 static int	st_mount_tape(dev_t, int);
    326 static void	st_unmount(struct st_softc *, boolean);
    327 static int	st_decide_mode(struct st_softc *, boolean);
    328 static void	ststart(struct scsipi_periph *);
    329 static void	strestart(void *);
    330 static void	stdone(struct scsipi_xfer *, int);
    331 static int	st_read(struct st_softc *, char *, int, int);
    332 static int	st_space(struct st_softc *, int, u_int, int);
    333 static int	st_write_filemarks(struct st_softc *, int, int);
    334 static int	st_check_eod(struct st_softc *, boolean, int *, int);
    335 static int	st_load(struct st_softc *, u_int, int);
    336 static int	st_rewind(struct st_softc *, u_int, int);
    337 static int	st_interpret_sense(struct scsipi_xfer *);
    338 static int	st_touch_tape(struct st_softc *);
    339 static int	st_erase(struct st_softc *, int full, int flags);
    340 static int	st_rdpos(struct st_softc *, int, u_int32_t *);
    341 static int	st_setpos(struct st_softc *, int, u_int32_t *);
    342 
    343 static const struct scsipi_periphsw st_switch = {
    344 	st_interpret_sense,
    345 	ststart,
    346 	NULL,
    347 	stdone
    348 };
    349 
    350 #if	defined(ST_ENABLE_EARLYWARN)
    351 #define	ST_INIT_FLAGS	ST_EARLYWARN
    352 #else
    353 #define	ST_INIT_FLAGS	0
    354 #endif
    355 
    356 /*
    357  * The routine called by the low level scsi routine when it discovers
    358  * A device suitable for this driver
    359  */
    360 void
    361 stattach(struct device *parent, struct st_softc *st, void *aux)
    362 {
    363 	struct scsipibus_attach_args *sa = aux;
    364 	struct scsipi_periph *periph = sa->sa_periph;
    365 
    366 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
    367 
    368 	/*
    369 	 * Store information needed to contact our base driver
    370 	 */
    371 	st->sc_periph = periph;
    372 	periph->periph_dev = &st->sc_dev;
    373 	periph->periph_switch = &st_switch;
    374 
    375 	/*
    376 	 * Set initial flags
    377 	 */
    378 
    379 	st->flags = ST_INIT_FLAGS;
    380 
    381 	/*
    382 	 * Set up the buf queue for this device
    383 	 */
    384 	bufq_alloc(&st->buf_queue, BUFQ_FCFS);
    385 
    386 	callout_init(&st->sc_callout);
    387 
    388 	/*
    389 	 * Check if the drive is a known criminal and take
    390 	 * Any steps needed to bring it into line
    391 	 */
    392 	st_identify_drive(st, &sa->sa_inqbuf);
    393 	/*
    394 	 * Use the subdriver to request information regarding the drive.
    395 	 */
    396 	printf("\n");
    397 	printf("%s: %s", st->sc_dev.dv_xname, st->quirkdata ? "rogue, " : "");
    398 	if (scsipi_test_unit_ready(periph,
    399 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
    400 	    st->ops(st, ST_OPS_MODESENSE,
    401 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
    402 		printf("drive empty\n");
    403 	else {
    404 		printf("density code %d, ", st->media_density);
    405 		if (st->media_blksize > 0)
    406 			printf("%d-byte", st->media_blksize);
    407 		else
    408 			printf("variable");
    409 		printf(" blocks, write-%s\n",
    410 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
    411 	}
    412 
    413 #if NRND > 0
    414 	rnd_attach_source(&st->rnd_source, st->sc_dev.dv_xname,
    415 			  RND_TYPE_TAPE, 0);
    416 #endif
    417 }
    418 
    419 int
    420 stactivate(struct device *self, enum devact act)
    421 {
    422 	int rv = 0;
    423 
    424 	switch (act) {
    425 	case DVACT_ACTIVATE:
    426 		rv = EOPNOTSUPP;
    427 		break;
    428 
    429 	case DVACT_DEACTIVATE:
    430 		/*
    431 		 * Nothing to do; we key off the device's DVF_ACTIVE.
    432 		 */
    433 		break;
    434 	}
    435 	return (rv);
    436 }
    437 
    438 int
    439 stdetach(struct device *self, int flags)
    440 {
    441 	struct st_softc *st = (struct st_softc *)self;
    442 	int s, bmaj, cmaj, mn;
    443 
    444 	/* locate the major number */
    445 	bmaj = bdevsw_lookup_major(&st_bdevsw);
    446 	cmaj = cdevsw_lookup_major(&st_cdevsw);
    447 
    448 	/* kill any pending restart */
    449 	callout_stop(&st->sc_callout);
    450 
    451 	s = splbio();
    452 
    453 	/* Kill off any queued buffers. */
    454 	bufq_drain(&st->buf_queue);
    455 
    456 	bufq_free(&st->buf_queue);
    457 
    458 	/* Kill off any pending commands. */
    459 	scsipi_kill_pending(st->sc_periph);
    460 
    461 	splx(s);
    462 
    463 	/* Nuke the vnodes for any open instances */
    464 	mn = STUNIT(self->dv_unit);
    465 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
    466 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
    467 
    468 
    469 #if NRND > 0
    470 	/* Unhook the entropy source. */
    471 	rnd_detach_source(&st->rnd_source);
    472 #endif
    473 
    474 	return (0);
    475 }
    476 
    477 /*
    478  * Use the inquiry routine in 'scsi_base' to get drive info so we can
    479  * Further tailor our behaviour.
    480  */
    481 static void
    482 st_identify_drive(struct st_softc *st, struct scsipi_inquiry_pattern *inqbuf)
    483 {
    484 	const struct st_quirk_inquiry_pattern *finger;
    485 	int priority;
    486 
    487 	finger = scsipi_inqmatch(inqbuf,
    488 	    st_quirk_patterns,
    489 	    sizeof(st_quirk_patterns) / sizeof(st_quirk_patterns[0]),
    490 	    sizeof(st_quirk_patterns[0]), &priority);
    491 	if (priority != 0) {
    492 		st->quirkdata = &finger->quirkdata;
    493 		st->drive_quirks = finger->quirkdata.quirks;
    494 		st->quirks = finger->quirkdata.quirks;	/* start value */
    495 		st->page_0_size = finger->quirkdata.page_0_size;
    496 		st_loadquirks(st);
    497 	}
    498 }
    499 
    500 /*
    501  * initialise the subdevices to the default (QUIRK) state.
    502  * this will remove any setting made by the system operator or previous
    503  * operations.
    504  */
    505 static void
    506 st_loadquirks(struct st_softc *st)
    507 {
    508 	int i;
    509 	const struct	modes *mode;
    510 	struct	modes *mode2;
    511 
    512 	mode = st->quirkdata->modes;
    513 	mode2 = st->modes;
    514 	for (i = 0; i < 4; i++) {
    515 		memset(mode2, 0, sizeof(struct modes));
    516 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
    517 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
    518 		    DENSITY_SET_BY_USER);
    519 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
    520 			mode2->blksize = mode->blksize;
    521 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
    522 		}
    523 		if (mode->density) {
    524 			mode2->density = mode->density;
    525 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
    526 		}
    527 		mode2->quirks |= mode->quirks;
    528 		mode++;
    529 		mode2++;
    530 	}
    531 }
    532 
    533 /*
    534  * open the device.
    535  */
    536 static int
    537 stopen(dev_t dev, int flags, int mode, struct proc *p)
    538 {
    539 	u_int stmode, dsty;
    540 	int error, sflags, unit, tries, ntries;
    541 	struct st_softc *st;
    542 	struct scsipi_periph *periph;
    543 	struct scsipi_adapter *adapt;
    544 
    545 	unit = STUNIT(dev);
    546 	if (unit >= st_cd.cd_ndevs)
    547 		return (ENXIO);
    548 	st = st_cd.cd_devs[unit];
    549 	if (st == NULL)
    550 		return (ENXIO);
    551 
    552 	stmode = STMODE(dev);
    553 	dsty = STDSTY(dev);
    554 
    555 	periph = st->sc_periph;
    556 	adapt = periph->periph_channel->chan_adapter;
    557 
    558 	SC_DEBUG(periph, SCSIPI_DB1, ("open: dev=0x%x (unit %d (of %d))\n", dev,
    559 	    unit, st_cd.cd_ndevs));
    560 
    561 
    562 	/*
    563 	 * Only allow one at a time
    564 	 */
    565 	if (periph->periph_flags & PERIPH_OPEN) {
    566 		printf("%s: already open\n", st->sc_dev.dv_xname);
    567 		return (EBUSY);
    568 	}
    569 
    570 	if ((error = scsipi_adapter_addref(adapt)) != 0)
    571 		return (error);
    572 
    573 	/*
    574 	 * clear any latched errors.
    575 	 */
    576 	st->mt_resid = 0;
    577 	st->mt_erreg = 0;
    578 	st->asc = 0;
    579 	st->ascq = 0;
    580 
    581 	/*
    582 	 * Catch any unit attention errors. Be silent about this
    583 	 * unless we're already mounted. We ignore media change
    584 	 * if we're in control mode or not mounted yet.
    585 	 */
    586 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
    587 #ifdef SCSIDEBUG
    588 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
    589 #else
    590 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
    591 #endif
    592 	} else
    593 		sflags = 0;
    594 
    595 	/*
    596 	 * If we're already mounted or we aren't configured for
    597 	 * a mount delay, only try a test unit ready once. Otherwise,
    598 	 * try up to ST_MOUNT_DELAY times with a rest interval of
    599 	 * one second between each try.
    600 	 */
    601 
    602 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0) {
    603 		ntries = 1;
    604 	} else {
    605 		ntries = ST_MOUNT_DELAY;
    606 	}
    607 
    608 	for (error = tries = 0; tries < ntries; tries++) {
    609 		int slpintr, oflags;
    610 
    611 		/*
    612 		 * If we had no error, or we're opening the control mode
    613 		 * device, we jump out right away.
    614 		 */
    615 
    616 		error = scsipi_test_unit_ready(periph, sflags);
    617 		if (error == 0 || stmode == CTRL_MODE) {
    618 			break;
    619 		}
    620 
    621 		/*
    622 		 * We had an error.
    623 		 *
    624 		 * If we're already mounted or we aren't configured for
    625 		 * a mount delay, or the error isn't a NOT READY error,
    626 		 * skip to the error exit now.
    627 		 */
    628 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
    629 		    (st->mt_key != SKEY_NOT_READY)) {
    630 			goto bad;
    631 		}
    632 
    633 		/*
    634 		 * clear any latched errors.
    635 		 */
    636 		st->mt_resid = 0;
    637 		st->mt_erreg = 0;
    638 		st->asc = 0;
    639 		st->ascq = 0;
    640 
    641 		/*
    642 		 * Fake that we have the device open so
    643 		 * we block other apps from getting in.
    644 		 */
    645 
    646 		oflags = periph->periph_flags;
    647 		periph->periph_flags |= PERIPH_OPEN;
    648 
    649 		slpintr = tsleep(&lbolt, PUSER|PCATCH, "stload", 0);
    650 
    651 		periph->periph_flags = oflags;	/* restore flags */
    652 		if (slpintr) {
    653 			goto bad;
    654 		}
    655 	}
    656 
    657 
    658 	/*
    659 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
    660 	 * been opened to set defaults and perform other, usually non-I/O
    661 	 * related, operations. In this case, do a quick check to see
    662 	 * whether the unit actually had a tape loaded (this will be known
    663 	 * as to whether or not we got a NOT READY for the above
    664 	 * unit attention). If a tape is there, go do a mount sequence.
    665 	 */
    666 	if (stmode == CTRL_MODE && st->mt_key == SKEY_NOT_READY) {
    667 		periph->periph_flags |= PERIPH_OPEN;
    668 		return (0);
    669 	}
    670 
    671 	/*
    672 	 * If we get this far and had an error set, that means we failed
    673 	 * to pass the 'test unit ready' test for the non-controlmode device,
    674 	 * so we bounce the open.
    675 	 */
    676 
    677 	if (error)
    678 		return (error);
    679 
    680 	/*
    681 	 * Else, we're now committed to saying we're open.
    682 	 */
    683 
    684 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
    685 
    686 	/*
    687 	 * If it's a different mode, or if the media has been
    688 	 * invalidated, unmount the tape from the previous
    689 	 * session but continue with open processing
    690 	 */
    691 	if (st->last_dsty != dsty ||
    692 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
    693 		st_unmount(st, NOEJECT);
    694 
    695 	/*
    696 	 * If we are not mounted, then we should start a new
    697 	 * mount session.
    698 	 */
    699 	if (!(st->flags & ST_MOUNTED)) {
    700 		if ((error = st_mount_tape(dev, flags)) != 0)
    701 			goto bad;
    702 		st->last_dsty = dsty;
    703 	}
    704 	if (!(st->quirks & ST_Q_NOPREVENT)) {
    705 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
    706 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
    707 	}
    708 
    709 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
    710 	return (0);
    711 
    712 bad:
    713 	st_unmount(st, NOEJECT);
    714 	scsipi_adapter_delref(adapt);
    715 	periph->periph_flags &= ~PERIPH_OPEN;
    716 	return (error);
    717 }
    718 
    719 /*
    720  * close the device.. only called if we are the LAST
    721  * occurence of an open device
    722  */
    723 static int
    724 stclose(dev_t dev, int flags, int mode, struct proc *p)
    725 {
    726 	int stxx, error = 0;
    727 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
    728 	struct scsipi_periph *periph = st->sc_periph;
    729 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
    730 
    731 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
    732 
    733 	/*
    734 	 * Make sure that a tape opened in write-only mode will have
    735 	 * file marks written on it when closed, even if not written to.
    736 	 *
    737 	 * This is for SUN compatibility. Actually, the Sun way of
    738 	 * things is to:
    739 	 *
    740 	 *	only write filemarks if there are fmks to be written and
    741 	 *   		- open for write (possibly read/write)
    742 	 *		- the last operation was a write
    743 	 * 	or:
    744 	 *		- opened for wronly
    745 	 *		- no data was written (including filemarks)
    746 	 */
    747 
    748 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
    749 	if (((flags & FWRITE) && stxx == ST_WRITTEN) ||
    750 	    ((flags & O_ACCMODE) == FWRITE && stxx == 0)) {
    751 		int nm;
    752 		error = st_check_eod(st, FALSE, &nm, 0);
    753 	}
    754 
    755 	/*
    756 	 * Allow robots to eject tape if needed.
    757 	 */
    758 	scsipi_prevent(periph, SPAMR_ALLOW,
    759 	    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
    760 
    761 	switch (STMODE(dev)) {
    762 	case NORMAL_MODE:
    763 		st_unmount(st, NOEJECT);
    764 		break;
    765 	case NOREW_MODE:
    766 	case CTRL_MODE:
    767 		/*
    768 		 * Leave mounted unless media seems to have been removed.
    769 		 *
    770 		 * Otherwise, if we're to terminate a tape with more than one
    771 		 * filemark [ and because we're not rewinding here ], backspace
    772 		 * one filemark so that later appends will see an unbroken
    773 		 * sequence of:
    774 		 *
    775 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
    776 		 */
    777 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
    778 			st_unmount(st, NOEJECT);
    779 		} else if (error == 0) {
    780 			/*
    781 			 * ST_WRITTEN was preserved from above.
    782 			 *
    783 			 * All we need to know here is:
    784 			 *
    785 			 *	Were we writing this tape and was the last
    786 			 *	operation a write?
    787 			 *
    788 			 *	Are there supposed to be 2FM at EOD?
    789 			 *
    790 			 * If both statements are true, then we backspace
    791 			 * one filemark.
    792 			 */
    793 			stxx |= (st->flags & ST_2FM_AT_EOD);
    794 			if ((flags & FWRITE) != 0 &&
    795 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
    796 				error = st_space(st, -1, SP_FILEMARKS, 0);
    797 			}
    798 		}
    799 		break;
    800 	case EJECT_MODE:
    801 		st_unmount(st, EJECT);
    802 		break;
    803 	}
    804 
    805 	scsipi_wait_drain(periph);
    806 
    807 	scsipi_adapter_delref(adapt);
    808 	periph->periph_flags &= ~PERIPH_OPEN;
    809 
    810 	return (error);
    811 }
    812 
    813 /*
    814  * Start a new mount session.
    815  * Copy in all the default parameters from the selected device mode.
    816  * and try guess any that seem to be defaulted.
    817  */
    818 static int
    819 st_mount_tape(dev_t dev, int flags)
    820 {
    821 	int unit;
    822 	u_int dsty;
    823 	struct st_softc *st;
    824 	struct scsipi_periph *periph;
    825 	int error = 0;
    826 
    827 	unit = STUNIT(dev);
    828 	dsty = STDSTY(dev);
    829 	st = st_cd.cd_devs[unit];
    830 	periph = st->sc_periph;
    831 
    832 	if (st->flags & ST_MOUNTED)
    833 		return (0);
    834 
    835 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
    836 	st->flags |= ST_NEW_MOUNT;
    837 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
    838 	/*
    839 	 * If the media is new, then make sure we give it a chance to
    840 	 * to do a 'load' instruction.  (We assume it is new.)
    841 	 */
    842 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
    843 		return (error);
    844 	/*
    845 	 * Throw another dummy instruction to catch
    846 	 * 'Unit attention' errors. Many drives give
    847 	 * these after doing a Load instruction (with
    848 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
    849 	 */
    850 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
    851 
    852 	/*
    853 	 * Some devices can't tell you much until they have been
    854 	 * asked to look at the media. This quirk does this.
    855 	 */
    856 	if (st->quirks & ST_Q_SENSE_HELP)
    857 		if ((error = st_touch_tape(st)) != 0)
    858 			return (error);
    859 	/*
    860 	 * Load the physical device parameters
    861 	 * loads: blkmin, blkmax
    862 	 */
    863 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
    864 		return (error);
    865 	/*
    866 	 * Load the media dependent parameters
    867 	 * includes: media_blksize,media_density,numblks
    868 	 * As we have a tape in, it should be reflected here.
    869 	 * If not you may need the "quirk" above.
    870 	 */
    871 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
    872 		return (error);
    873 	/*
    874 	 * If we have gained a permanent density from somewhere,
    875 	 * then use it in preference to the one supplied by
    876 	 * default by the driver.
    877 	 */
    878 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
    879 		st->density = st->modes[dsty].density;
    880 	else
    881 		st->density = st->media_density;
    882 	/*
    883 	 * If we have gained a permanent blocksize
    884 	 * then use it in preference to the one supplied by
    885 	 * default by the driver.
    886 	 */
    887 	st->flags &= ~ST_FIXEDBLOCKS;
    888 	if (st->modeflags[dsty] &
    889 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
    890 		st->blksize = st->modes[dsty].blksize;
    891 		if (st->blksize)
    892 			st->flags |= ST_FIXEDBLOCKS;
    893 	} else {
    894 		if ((error = st_decide_mode(st, FALSE)) != 0)
    895 			return (error);
    896 	}
    897 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
    898 		/* ATAPI will return ENODEV for this, and this may be OK */
    899 		if (error != ENODEV) {
    900 			printf("%s: cannot set selected mode\n",
    901 			    st->sc_dev.dv_xname);
    902 			return (error);
    903 		}
    904 	}
    905 	st->flags &= ~ST_NEW_MOUNT;
    906 	st->flags |= ST_MOUNTED;
    907 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
    908 	st->blkno = st->fileno = (daddr_t) 0;
    909 	return (0);
    910 }
    911 
    912 /*
    913  * End the present mount session.
    914  * Rewind, and optionally eject the tape.
    915  * Reset various flags to indicate that all new
    916  * operations require another mount operation
    917  */
    918 static void
    919 st_unmount(struct st_softc *st, boolean eject)
    920 {
    921 	struct scsipi_periph *periph = st->sc_periph;
    922 	int nmarks;
    923 
    924 	if ((st->flags & ST_MOUNTED) == 0)
    925 		return;
    926 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
    927 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
    928 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
    929 
    930 	/*
    931 	 * Section 9.3.3 of the SCSI specs states that a device shall return
    932 	 * the density value specified in the last succesfull MODE SELECT
    933 	 * after an unload operation, in case it is not able to
    934 	 * automatically determine the density of the new medium.
    935 	 *
    936 	 * So we instruct the device to use the default density, which will
    937 	 * prevent the use of stale density values (in particular,
    938 	 * in st_touch_tape().
    939 	 */
    940 	st->density = 0;
    941 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
    942 		printf("%s: WARNING: cannot revert to default density\n",
    943 			st->sc_dev.dv_xname);
    944 	}
    945 
    946 	if (eject) {
    947 		if (!(st->quirks & ST_Q_NOPREVENT)) {
    948 			scsipi_prevent(periph, SPAMR_ALLOW,
    949 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
    950 			    XS_CTL_IGNORE_NOT_READY);
    951 		}
    952 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
    953 		st->blkno = st->fileno = (daddr_t) -1;
    954 	} else {
    955 		st->blkno = st->fileno = (daddr_t) 0;
    956 	}
    957 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
    958 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
    959 }
    960 
    961 /*
    962  * Given all we know about the device, media, mode, 'quirks' and
    963  * initial operation, make a decision as to how we should be set
    964  * to run (regarding blocking and EOD marks)
    965  */
    966 int
    967 st_decide_mode(struct st_softc *st, boolean first_read)
    968 {
    969 
    970 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
    971 
    972 	/*
    973 	 * If the drive can only handle fixed-length blocks and only at
    974 	 * one size, perhaps we should just do that.
    975 	 */
    976 	if (st->blkmin && (st->blkmin == st->blkmax)) {
    977 		st->flags |= ST_FIXEDBLOCKS;
    978 		st->blksize = st->blkmin;
    979 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
    980 		    ("blkmin == blkmax of %d\n", st->blkmin));
    981 		goto done;
    982 	}
    983 	/*
    984 	 * If the tape density mandates (or even suggests) use of fixed
    985 	 * or variable-length blocks, comply.
    986 	 */
    987 	switch (st->density) {
    988 	case HALFINCH_800:
    989 	case HALFINCH_1600:
    990 	case HALFINCH_6250:
    991 	case DDS:
    992 		st->flags &= ~ST_FIXEDBLOCKS;
    993 		st->blksize = 0;
    994 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
    995 		    ("density specified variable\n"));
    996 		goto done;
    997 	case QIC_11:
    998 	case QIC_24:
    999 	case QIC_120:
   1000 	case QIC_150:
   1001 	case QIC_525:
   1002 	case QIC_1320:
   1003 	case QIC_3095:
   1004 	case QIC_3220:
   1005 		st->flags |= ST_FIXEDBLOCKS;
   1006 		if (st->media_blksize > 0)
   1007 			st->blksize = st->media_blksize;
   1008 		else
   1009 			st->blksize = DEF_FIXED_BSIZE;
   1010 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1011 		    ("density specified fixed\n"));
   1012 		goto done;
   1013 	}
   1014 	/*
   1015 	 * If we're about to read the tape, perhaps we should choose
   1016 	 * fixed or variable-length blocks and block size according to
   1017 	 * what the drive found on the tape.
   1018 	 */
   1019 	if (first_read &&
   1020 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
   1021 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
   1022 	    (st->media_blksize == 1024))) {
   1023 		if (st->media_blksize > 0)
   1024 			st->flags |= ST_FIXEDBLOCKS;
   1025 		else
   1026 			st->flags &= ~ST_FIXEDBLOCKS;
   1027 		st->blksize = st->media_blksize;
   1028 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1029 		    ("Used media_blksize of %d\n", st->media_blksize));
   1030 		goto done;
   1031 	}
   1032 	/*
   1033 	 * We're getting no hints from any direction.  Choose variable-
   1034 	 * length blocks arbitrarily.
   1035 	 */
   1036 	st->flags &= ~ST_FIXEDBLOCKS;
   1037 	st->blksize = 0;
   1038 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1039 	    ("Give up and default to variable mode\n"));
   1040 
   1041 done:
   1042 	/*
   1043 	 * Decide whether or not to write two file marks to signify end-
   1044 	 * of-data.  Make the decision as a function of density.  If
   1045 	 * the decision is not to use a second file mark, the SCSI BLANK
   1046 	 * CHECK condition code will be recognized as end-of-data when
   1047 	 * first read.
   1048 	 * (I think this should be a by-product of fixed/variable..julian)
   1049 	 */
   1050 	switch (st->density) {
   1051 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
   1052 	case QIC_11:
   1053 	case QIC_24:
   1054 	case QIC_120:
   1055 	case QIC_150:
   1056 	case QIC_525:
   1057 	case QIC_1320:
   1058 	case QIC_3095:
   1059 	case QIC_3220:
   1060 		st->flags &= ~ST_2FM_AT_EOD;
   1061 		break;
   1062 	default:
   1063 		st->flags |= ST_2FM_AT_EOD;
   1064 	}
   1065 	return (0);
   1066 }
   1067 
   1068 /*
   1069  * Actually translate the requested transfer into
   1070  * one the physical driver can understand
   1071  * The transfer is described by a buf and will include
   1072  * only one physical transfer.
   1073  */
   1074 static void
   1075 ststrategy(struct buf *bp)
   1076 {
   1077 	struct st_softc *st = st_cd.cd_devs[STUNIT(bp->b_dev)];
   1078 	int s;
   1079 
   1080 	SC_DEBUG(st->sc_periph, SCSIPI_DB1,
   1081 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount, bp->b_blkno));
   1082 	/*
   1083 	 * If it's a null transfer, return immediatly
   1084 	 */
   1085 	if (bp->b_bcount == 0)
   1086 		goto done;
   1087 
   1088 	/* If offset is negative, error */
   1089 	if (bp->b_blkno < 0) {
   1090 		bp->b_error = EINVAL;
   1091 		goto bad;
   1092 	}
   1093 
   1094 	/*
   1095 	 * Odd sized request on fixed drives are verboten
   1096 	 */
   1097 	if (st->flags & ST_FIXEDBLOCKS) {
   1098 		if (bp->b_bcount % st->blksize) {
   1099 			printf("%s: bad request, must be multiple of %d\n",
   1100 			    st->sc_dev.dv_xname, st->blksize);
   1101 			bp->b_error = EIO;
   1102 			goto bad;
   1103 		}
   1104 	}
   1105 	/*
   1106 	 * as are out-of-range requests on variable drives.
   1107 	 */
   1108 	else if (bp->b_bcount < st->blkmin ||
   1109 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
   1110 		printf("%s: bad request, must be between %d and %d\n",
   1111 		    st->sc_dev.dv_xname, st->blkmin, st->blkmax);
   1112 		bp->b_error = EIO;
   1113 		goto bad;
   1114 	}
   1115 	s = splbio();
   1116 
   1117 	/*
   1118 	 * Place it in the queue of activities for this tape
   1119 	 * at the end (a bit silly because we only have on user..
   1120 	 * (but it could fork()))
   1121 	 */
   1122 	BUFQ_PUT(&st->buf_queue, bp);
   1123 
   1124 	/*
   1125 	 * Tell the device to get going on the transfer if it's
   1126 	 * not doing anything, otherwise just wait for completion
   1127 	 * (All a bit silly if we're only allowing 1 open but..)
   1128 	 */
   1129 	ststart(st->sc_periph);
   1130 
   1131 	splx(s);
   1132 	return;
   1133 bad:
   1134 	bp->b_flags |= B_ERROR;
   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((caddr_t)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_flags |= B_ERROR;
   1190 				bp->b_error = EIO;
   1191 				bp->b_resid = bp->b_bcount;
   1192 				biodone(bp);
   1193 				continue;
   1194 			} else {
   1195 				return;
   1196 			}
   1197 		}
   1198 
   1199 		if ((bp = BUFQ_PEEK(&st->buf_queue)) == NULL)
   1200 			return;
   1201 
   1202 		/*
   1203 		 * only FIXEDBLOCK devices have pending I/O or space operations.
   1204 		 */
   1205 		if (st->flags & ST_FIXEDBLOCKS) {
   1206 			/*
   1207 			 * If we are at a filemark but have not reported it yet
   1208 			 * then we should report it now
   1209 			 */
   1210 			if (st->flags & ST_AT_FILEMARK) {
   1211 				if ((bp->b_flags & B_READ) == B_WRITE) {
   1212 					/*
   1213 					 * Handling of ST_AT_FILEMARK in
   1214 					 * st_space will fill in the right file
   1215 					 * mark count.
   1216 					 * Back up over filemark
   1217 					 */
   1218 					if (st_space(st, 0, SP_FILEMARKS, 0)) {
   1219 						BUFQ_GET(&st->buf_queue);
   1220 						bp->b_flags |= B_ERROR;
   1221 						bp->b_error = EIO;
   1222 						biodone(bp);
   1223 						continue;
   1224 					}
   1225 				} else {
   1226 					BUFQ_GET(&st->buf_queue);
   1227 					bp->b_resid = bp->b_bcount;
   1228 					bp->b_error = 0;
   1229 					bp->b_flags &= ~B_ERROR;
   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 				bp->b_flags |= B_ERROR;
   1246 			}
   1247 			st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
   1248 			biodone(bp);
   1249 			continue;	/* seek more work */
   1250 		}
   1251 
   1252 		/*
   1253 		 * Fill out the scsi command
   1254 		 */
   1255 		memset(&cmd, 0, sizeof(cmd));
   1256 		flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
   1257 		if ((bp->b_flags & B_READ) == B_WRITE) {
   1258 			cmd.opcode = WRITE;
   1259 			st->flags &= ~ST_FM_WRITTEN;
   1260 			flags |= XS_CTL_DATA_OUT;
   1261 		} else {
   1262 			cmd.opcode = READ;
   1263 			flags |= XS_CTL_DATA_IN;
   1264 		}
   1265 
   1266 		/*
   1267 		 * Handle "fixed-block-mode" tape drives by using the
   1268 		 * block count instead of the length.
   1269 		 */
   1270 		if (st->flags & ST_FIXEDBLOCKS) {
   1271 			cmd.byte2 |= SRW_FIXED;
   1272 			_lto3b(bp->b_bcount / st->blksize, cmd.len);
   1273 		} else
   1274 			_lto3b(bp->b_bcount, cmd.len);
   1275 
   1276 		/*
   1277 		 * Clear 'position updated' indicator
   1278 		 */
   1279 		st->flags &= ~ST_POSUPDATED;
   1280 
   1281 		/*
   1282 		 * go ask the adapter to do all this for us
   1283 		 */
   1284 		xs = scsipi_make_xs(periph,
   1285 		    (struct scsipi_generic *)&cmd, sizeof(cmd),
   1286 		    (u_char *)bp->b_data, bp->b_bcount,
   1287 		    0, ST_IO_TIME, bp, flags);
   1288 		if (__predict_false(xs == NULL)) {
   1289 			/*
   1290 			 * out of memory. Keep this buffer in the queue, and
   1291 			 * retry later.
   1292 			 */
   1293 			callout_reset(&st->sc_callout, hz / 2, strestart,
   1294 			    periph);
   1295 			return;
   1296 		}
   1297 		/*
   1298 		 * need to dequeue the buffer before queuing the command,
   1299 		 * because cdstart may be called recursively from the
   1300 		 * HBA driver
   1301 		 */
   1302 #ifdef DIAGNOSTIC
   1303 		if (BUFQ_GET(&st->buf_queue) != bp)
   1304 			panic("ststart(): dequeued wrong buf");
   1305 #else
   1306 		BUFQ_GET(&st->buf_queue);
   1307 #endif
   1308 		error = scsipi_execute_xs(xs);
   1309 		/* with a scsipi_xfer preallocated, scsipi_command can't fail */
   1310 		KASSERT(error == 0);
   1311 	} /* go back and see if we can cram more work in.. */
   1312 }
   1313 
   1314 static void
   1315 strestart(void *v)
   1316 {
   1317 	int s = splbio();
   1318 	ststart((struct scsipi_periph *)v);
   1319 	splx(s);
   1320 }
   1321 
   1322 
   1323 static void
   1324 stdone(struct scsipi_xfer *xs, int error)
   1325 {
   1326 	struct st_softc *st = (void *)xs->xs_periph->periph_dev;
   1327 	struct buf *bp = xs->bp;
   1328 
   1329 	if (bp) {
   1330 		bp->b_error = error;
   1331 		bp->b_resid = xs->resid;
   1332 		if (error)
   1333 			bp->b_flags |= B_ERROR;
   1334 
   1335 		if ((bp->b_flags & B_READ) == B_WRITE)
   1336 			st->flags |= ST_WRITTEN;
   1337 		else
   1338 			st->flags &= ~ST_WRITTEN;
   1339 #if NRND > 0
   1340 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
   1341 #endif
   1342 
   1343 		if ((st->flags & ST_POSUPDATED) == 0) {
   1344 			if (error) {
   1345 				st->fileno = st->blkno = -1;
   1346 			} else if (st->blkno != -1) {
   1347 				if (st->flags & ST_FIXEDBLOCKS)
   1348 					st->blkno +=
   1349 					    (bp->b_bcount / st->blksize);
   1350 				else
   1351 					st->blkno++;
   1352 			}
   1353 		}
   1354 
   1355 		biodone(bp);
   1356 	}
   1357 }
   1358 
   1359 static int
   1360 stread(dev_t dev, struct uio *uio, int iomode)
   1361 {
   1362 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
   1363 
   1364 	return (physio(ststrategy, NULL, dev, B_READ,
   1365 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
   1366 }
   1367 
   1368 static int
   1369 stwrite(dev_t dev, struct uio *uio, int iomode)
   1370 {
   1371 	struct st_softc *st = st_cd.cd_devs[STUNIT(dev)];
   1372 
   1373 	return (physio(ststrategy, NULL, dev, B_WRITE,
   1374 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio));
   1375 }
   1376 
   1377 /*
   1378  * Perform special action on behalf of the user;
   1379  * knows about the internals of this device
   1380  */
   1381 static int
   1382 stioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct proc *p)
   1383 {
   1384 	int error = 0;
   1385 	int unit;
   1386 	int number, nmarks, dsty;
   1387 	int flags;
   1388 	struct st_softc *st;
   1389 	int hold_blksize;
   1390 	u_int8_t hold_density;
   1391 	struct mtop *mt = (struct mtop *) arg;
   1392 
   1393 	/*
   1394 	 * Find the device that the user is talking about
   1395 	 */
   1396 	flags = 0;		/* give error messages, act on errors etc. */
   1397 	unit = STUNIT(dev);
   1398 	dsty = STDSTY(dev);
   1399 	st = st_cd.cd_devs[unit];
   1400 	hold_blksize = st->blksize;
   1401 	hold_density = st->density;
   1402 
   1403 	switch ((u_int) cmd) {
   1404 
   1405 	case MTIOCGET: {
   1406 		struct mtget *g = (struct mtget *) arg;
   1407 		/*
   1408 		 * (to get the current state of READONLY)
   1409 		 */
   1410 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
   1411 		if (error) {
   1412 			/*
   1413 			 * Ignore the error if in control mode;
   1414 			 * this is mandated by st(4).
   1415 			 */
   1416 			if (STMODE(dev) != CTRL_MODE)
   1417 				break;
   1418 			error = 0;
   1419 		}
   1420 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
   1421 		memset(g, 0, sizeof(struct mtget));
   1422 		g->mt_type = 0x7;	/* Ultrix compat *//*? */
   1423 		g->mt_blksiz = st->blksize;
   1424 		g->mt_density = st->density;
   1425 		g->mt_mblksiz[0] = st->modes[0].blksize;
   1426 		g->mt_mblksiz[1] = st->modes[1].blksize;
   1427 		g->mt_mblksiz[2] = st->modes[2].blksize;
   1428 		g->mt_mblksiz[3] = st->modes[3].blksize;
   1429 		g->mt_mdensity[0] = st->modes[0].density;
   1430 		g->mt_mdensity[1] = st->modes[1].density;
   1431 		g->mt_mdensity[2] = st->modes[2].density;
   1432 		g->mt_mdensity[3] = st->modes[3].density;
   1433 		g->mt_fileno = st->fileno;
   1434 		g->mt_blkno = st->blkno;
   1435 		if (st->flags & ST_READONLY)
   1436 			g->mt_dsreg |= MT_DS_RDONLY;
   1437 		if (st->flags & ST_MOUNTED)
   1438 			g->mt_dsreg |= MT_DS_MOUNTED;
   1439 		g->mt_resid = st->mt_resid;
   1440 		g->mt_erreg = st->mt_erreg;
   1441 		/*
   1442 		 * clear latched errors.
   1443 		 */
   1444 		st->mt_resid = 0;
   1445 		st->mt_erreg = 0;
   1446 		st->asc = 0;
   1447 		st->ascq = 0;
   1448 		break;
   1449 	}
   1450 	case MTIOCTOP: {
   1451 
   1452 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
   1453 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
   1454 			mt->mt_count));
   1455 
   1456 		/* compat: in U*x it is a short */
   1457 		number = mt->mt_count;
   1458 		switch ((short) (mt->mt_op)) {
   1459 		case MTWEOF:	/* write an end-of-file record */
   1460 			error = st_write_filemarks(st, number, flags);
   1461 			break;
   1462 		case MTBSF:	/* backward space file */
   1463 			number = -number;
   1464 		case MTFSF:	/* forward space file */
   1465 			error = st_check_eod(st, FALSE, &nmarks, flags);
   1466 			if (!error)
   1467 				error = st_space(st, number - nmarks,
   1468 				    SP_FILEMARKS, flags);
   1469 			break;
   1470 		case MTBSR:	/* backward space record */
   1471 			number = -number;
   1472 		case MTFSR:	/* forward space record */
   1473 			error = st_check_eod(st, TRUE, &nmarks, flags);
   1474 			if (!error)
   1475 				error = st_space(st, number, SP_BLKS, flags);
   1476 			break;
   1477 		case MTREW:	/* rewind */
   1478 			error = st_rewind(st, 0, flags);
   1479 			break;
   1480 		case MTOFFL:	/* rewind and put the drive offline */
   1481 			st_unmount(st, EJECT);
   1482 			break;
   1483 		case MTNOP:	/* no operation, sets status only */
   1484 			break;
   1485 		case MTRETEN:	/* retension the tape */
   1486 			error = st_load(st, LD_RETENSION, flags);
   1487 			if (!error)
   1488 				error = st_load(st, LD_LOAD, flags);
   1489 			break;
   1490 		case MTEOM:	/* forward space to end of media */
   1491 			error = st_check_eod(st, FALSE, &nmarks, flags);
   1492 			if (!error)
   1493 				error = st_space(st, 1, SP_EOM, flags);
   1494 			break;
   1495 		case MTCACHE:	/* enable controller cache */
   1496 			st->flags &= ~ST_DONTBUFFER;
   1497 			goto try_new_value;
   1498 		case MTNOCACHE:	/* disable controller cache */
   1499 			st->flags |= ST_DONTBUFFER;
   1500 			goto try_new_value;
   1501 		case MTERASE:	/* erase volume */
   1502 			error = st_erase(st, number, flags);
   1503 			break;
   1504 		case MTSETBSIZ:	/* Set block size for device */
   1505 #ifdef	NOTYET
   1506 			if (!(st->flags & ST_NEW_MOUNT)) {
   1507 				uprintf("re-mount tape before changing blocksize");
   1508 				error = EINVAL;
   1509 				break;
   1510 			}
   1511 #endif
   1512 			if (number == 0)
   1513 				st->flags &= ~ST_FIXEDBLOCKS;
   1514 			else {
   1515 				if ((st->blkmin || st->blkmax) &&
   1516 				    (number < st->blkmin ||
   1517 				    number > st->blkmax)) {
   1518 					error = EINVAL;
   1519 					break;
   1520 				}
   1521 				st->flags |= ST_FIXEDBLOCKS;
   1522 			}
   1523 			st->blksize = number;
   1524 			st->flags |= ST_BLOCK_SET;	/*XXX */
   1525 			goto try_new_value;
   1526 
   1527 		case MTSETDNSTY:	/* Set density for device and mode */
   1528 			/*
   1529 			 * Any number >= 0 and <= 0xff is legal. Numbers
   1530 			 * above 0x80 are 'vendor unique'.
   1531 			 */
   1532 			if (number < 0 || number > 255) {
   1533 				error = EINVAL;
   1534 				break;
   1535 			} else
   1536 				st->density = number;
   1537 			goto try_new_value;
   1538 
   1539 		case MTCMPRESS:
   1540 			error = st->ops(st, (number == 0) ?
   1541 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
   1542 			    XS_CTL_SILENT);
   1543 			break;
   1544 
   1545 		case MTEWARN:
   1546 			if (number)
   1547 				st->flags |= ST_EARLYWARN;
   1548 			else
   1549 				st->flags &= ~ST_EARLYWARN;
   1550 			break;
   1551 
   1552 		default:
   1553 			error = EINVAL;
   1554 		}
   1555 		break;
   1556 	}
   1557 	case MTIOCIEOT:
   1558 	case MTIOCEEOT:
   1559 		break;
   1560 
   1561 	case MTIOCRDSPOS:
   1562 		error = st_rdpos(st, 0, (u_int32_t *) arg);
   1563 		break;
   1564 
   1565 	case MTIOCRDHPOS:
   1566 		error = st_rdpos(st, 1, (u_int32_t *) arg);
   1567 		break;
   1568 
   1569 	case MTIOCSLOCATE:
   1570 		error = st_setpos(st, 0, (u_int32_t *) arg);
   1571 		break;
   1572 
   1573 	case MTIOCHLOCATE:
   1574 		error = st_setpos(st, 1, (u_int32_t *) arg);
   1575 		break;
   1576 
   1577 
   1578 	default:
   1579 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg,
   1580 					flag, p);
   1581 		break;
   1582 	}
   1583 	return (error);
   1584 /*-----------------------------*/
   1585 try_new_value:
   1586 	/*
   1587 	 * Check that the mode being asked for is aggreeable to the
   1588 	 * drive. If not, put it back the way it was.
   1589 	 *
   1590 	 * If in control mode, we can make (persistent) mode changes
   1591 	 * even if no medium is loaded (see st(4)).
   1592 	 */
   1593 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
   1594 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
   1595 		/* put it back as it was */
   1596 		printf("%s: cannot set selected mode\n", st->sc_dev.dv_xname);
   1597 		st->density = hold_density;
   1598 		st->blksize = hold_blksize;
   1599 		if (st->blksize)
   1600 			st->flags |= ST_FIXEDBLOCKS;
   1601 		else
   1602 			st->flags &= ~ST_FIXEDBLOCKS;
   1603 		return (error);
   1604 	}
   1605 	/*
   1606 	 * As the drive liked it, if we are setting a new default,
   1607 	 * set it into the structures as such.
   1608 	 *
   1609 	 * The means for deciding this are not finalised yet- but
   1610 	 * if the device was opened in Control Mode, the values
   1611 	 * are persistent now across mounts.
   1612 	 */
   1613 	if (STMODE(dev) == CTRL_MODE) {
   1614 		switch ((short) (mt->mt_op)) {
   1615 		case MTSETBSIZ:
   1616 			st->modes[dsty].blksize = st->blksize;
   1617 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
   1618 			break;
   1619 		case MTSETDNSTY:
   1620 			st->modes[dsty].density = st->density;
   1621 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
   1622 			break;
   1623 		}
   1624 	}
   1625 	return (0);
   1626 }
   1627 
   1628 /*
   1629  * Do a synchronous read.
   1630  */
   1631 static int
   1632 st_read(struct st_softc *st, char *bf, int size, int flags)
   1633 {
   1634 	struct scsi_rw_tape cmd;
   1635 
   1636 	/*
   1637 	 * If it's a null transfer, return immediatly
   1638 	 */
   1639 	if (size == 0)
   1640 		return (0);
   1641 	memset(&cmd, 0, sizeof(cmd));
   1642 	cmd.opcode = READ;
   1643 	if (st->flags & ST_FIXEDBLOCKS) {
   1644 		cmd.byte2 |= SRW_FIXED;
   1645 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
   1646 		    cmd.len);
   1647 	} else
   1648 		_lto3b(size, cmd.len);
   1649 	return (scsipi_command(st->sc_periph,
   1650 	    (void *)&cmd, sizeof(cmd), (void *)bf, size, 0, ST_IO_TIME, NULL,
   1651 	    flags | XS_CTL_DATA_IN));
   1652 }
   1653 
   1654 /*
   1655  * issue an erase command
   1656  */
   1657 static int
   1658 st_erase(struct st_softc *st, int full, int flags)
   1659 {
   1660 	int tmo;
   1661 	struct scsi_erase cmd;
   1662 
   1663 	/*
   1664 	 * Full erase means set LONG bit in erase command, which asks
   1665 	 * the drive to erase the entire unit.  Without this bit, we're
   1666 	 * asking the drive to write an erase gap.
   1667 	 */
   1668 	memset(&cmd, 0, sizeof(cmd));
   1669 	cmd.opcode = ERASE;
   1670 	if (full) {
   1671 		cmd.byte2 = SE_LONG;
   1672 		tmo = ST_SPC_TIME;
   1673 	} else {
   1674 		tmo = ST_IO_TIME;
   1675 	}
   1676 
   1677 	/*
   1678 	 * XXX We always do this asynchronously, for now, unless the device
   1679 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
   1680 	 * want to (eventually) to it synchronously?
   1681 	 */
   1682 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
   1683 		cmd.byte2 |= SE_IMMED;
   1684 
   1685 	return (scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1686 	    ST_RETRIES, tmo, NULL, flags));
   1687 }
   1688 
   1689 /*
   1690  * skip N blocks/filemarks/seq filemarks/eom
   1691  */
   1692 static int
   1693 st_space(struct st_softc *st, int number, u_int what, int flags)
   1694 {
   1695 	struct scsi_space cmd;
   1696 	int error;
   1697 
   1698 	switch (what) {
   1699 	case SP_BLKS:
   1700 		if (st->flags & ST_PER_ACTION) {
   1701 			if (number > 0) {
   1702 				st->flags &= ~ST_PER_ACTION;
   1703 				return (EIO);
   1704 			} else if (number < 0) {
   1705 				if (st->flags & ST_AT_FILEMARK) {
   1706 					/*
   1707 					 * Handling of ST_AT_FILEMARK
   1708 					 * in st_space will fill in the
   1709 					 * right file mark count.
   1710 					 */
   1711 					error = st_space(st, 0, SP_FILEMARKS,
   1712 					    flags);
   1713 					if (error)
   1714 						return (error);
   1715 				}
   1716 				if (st->flags & ST_BLANK_READ) {
   1717 					st->flags &= ~ST_BLANK_READ;
   1718 					return (EIO);
   1719 				}
   1720 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
   1721 			}
   1722 		}
   1723 		break;
   1724 	case SP_FILEMARKS:
   1725 		if (st->flags & ST_EIO_PENDING) {
   1726 			if (number > 0) {
   1727 				/* pretend we just discovered the error */
   1728 				st->flags &= ~ST_EIO_PENDING;
   1729 				return (EIO);
   1730 			} else if (number < 0) {
   1731 				/* back away from the error */
   1732 				st->flags &= ~ST_EIO_PENDING;
   1733 			}
   1734 		}
   1735 		if (st->flags & ST_AT_FILEMARK) {
   1736 			st->flags &= ~ST_AT_FILEMARK;
   1737 			number--;
   1738 		}
   1739 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
   1740 			/* back away from unwritten tape */
   1741 			st->flags &= ~ST_BLANK_READ;
   1742 			number++;	/* XXX dubious */
   1743 		}
   1744 		break;
   1745 	case SP_EOM:
   1746 		if (st->flags & ST_EOM_PENDING) {
   1747 			/* we're already there */
   1748 			st->flags &= ~ST_EOM_PENDING;
   1749 			return (0);
   1750 		}
   1751 		if (st->flags & ST_EIO_PENDING) {
   1752 			/* pretend we just discovered the error */
   1753 			st->flags &= ~ST_EIO_PENDING;
   1754 			return (EIO);
   1755 		}
   1756 		if (st->flags & ST_AT_FILEMARK)
   1757 			st->flags &= ~ST_AT_FILEMARK;
   1758 		break;
   1759 	}
   1760 	if (number == 0)
   1761 		return (0);
   1762 
   1763 	memset(&cmd, 0, sizeof(cmd));
   1764 	cmd.opcode = SPACE;
   1765 	cmd.byte2 = what;
   1766 	_lto3b(number, cmd.number);
   1767 
   1768 	st->flags &= ~ST_POSUPDATED;
   1769 	st->last_ctl_resid = 0;
   1770 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1771 	    0, ST_SPC_TIME, NULL, flags);
   1772 
   1773 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
   1774 		number = number - st->last_ctl_resid;
   1775 		if (what == SP_BLKS) {
   1776 			if (st->blkno != -1) {
   1777 				st->blkno += number;
   1778 			}
   1779 		} else if (what == SP_FILEMARKS) {
   1780 			if (st->fileno != -1) {
   1781 				st->fileno += number;
   1782 				if (number > 0) {
   1783 					st->blkno = 0;
   1784 				} else if (number < 0) {
   1785 					st->blkno = -1;
   1786 				}
   1787 			}
   1788 		} else if (what == SP_EOM) {
   1789 			/*
   1790 			 * This loses us relative position.
   1791 			 */
   1792 			st->fileno = st->blkno = -1;
   1793 		}
   1794 	}
   1795 	return (error);
   1796 }
   1797 
   1798 /*
   1799  * write N filemarks
   1800  */
   1801 static int
   1802 st_write_filemarks(struct st_softc *st, int number, int flags)
   1803 {
   1804 	int error;
   1805 	struct scsi_write_filemarks cmd;
   1806 
   1807 	/*
   1808 	 * It's hard to write a negative number of file marks.
   1809 	 * Don't try.
   1810 	 */
   1811 	if (number < 0)
   1812 		return (EINVAL);
   1813 	switch (number) {
   1814 	case 0:		/* really a command to sync the drive's buffers */
   1815 		break;
   1816 	case 1:
   1817 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
   1818 			st->flags &= ~ST_WRITTEN;
   1819 		else
   1820 			st->flags |= ST_FM_WRITTEN;
   1821 		st->flags &= ~ST_PER_ACTION;
   1822 		break;
   1823 	default:
   1824 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
   1825 	}
   1826 
   1827 	memset(&cmd, 0, sizeof(cmd));
   1828 	cmd.opcode = WRITE_FILEMARKS;
   1829 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
   1830 		cmd.byte2 = SR_IMMED;
   1831 	/*
   1832 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
   1833 	 * WRITE_FILEMARKS is still used to flush the buffer
   1834 	 */
   1835 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
   1836 		_lto3b(number, cmd.number);
   1837 
   1838 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
   1839 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1840 	    0, ST_IO_TIME * 4, NULL, flags);
   1841 	if (error == 0 && st->fileno != -1) {
   1842 		st->fileno += number;
   1843 	}
   1844 	return (error);
   1845 }
   1846 
   1847 /*
   1848  * Make sure the right number of file marks is on tape if the
   1849  * tape has been written.  If the position argument is true,
   1850  * leave the tape positioned where it was originally.
   1851  *
   1852  * nmarks returns the number of marks to skip (or, if position
   1853  * true, which were skipped) to get back original position.
   1854  */
   1855 static int
   1856 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
   1857 {
   1858 	int error;
   1859 
   1860 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
   1861 	default:
   1862 		*nmarks = 0;
   1863 		return (0);
   1864 	case ST_WRITTEN:
   1865 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
   1866 		*nmarks = 1;
   1867 		break;
   1868 	case ST_WRITTEN | ST_2FM_AT_EOD:
   1869 		*nmarks = 2;
   1870 	}
   1871 	error = st_write_filemarks(st, *nmarks, flags);
   1872 	if (position && !error)
   1873 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
   1874 	return (error);
   1875 }
   1876 
   1877 /*
   1878  * load/unload/retension
   1879  */
   1880 static int
   1881 st_load(struct st_softc *st, u_int type, int flags)
   1882 {
   1883 	int error;
   1884 	struct scsi_load cmd;
   1885 
   1886 	if (type != LD_LOAD) {
   1887 		int nmarks;
   1888 
   1889 		error = st_check_eod(st, FALSE, &nmarks, flags);
   1890 		if (error) {
   1891 			printf("%s: failed to write closing filemarks at "
   1892 			    "unload, errno=%d\n", st->sc_dev.dv_xname, error);
   1893 			return (error);
   1894 		}
   1895 	}
   1896 	if (st->quirks & ST_Q_IGNORE_LOADS) {
   1897 		if (type == LD_LOAD) {
   1898 			/*
   1899 			 * If we ignore loads, at least we should try a rewind.
   1900 			 */
   1901 			return st_rewind(st, 0, flags);
   1902 		}
   1903 		/* otherwise, we should do what's asked of us */
   1904 	}
   1905 
   1906 	memset(&cmd, 0, sizeof(cmd));
   1907 	cmd.opcode = LOAD;
   1908 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
   1909 		cmd.byte2 = SR_IMMED;
   1910 	cmd.how = type;
   1911 
   1912 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1913 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
   1914 	if (error) {
   1915 		printf("%s: error %d in st_load (op %d)\n",
   1916 		    st->sc_dev.dv_xname, error, type);
   1917 	}
   1918 	return (error);
   1919 }
   1920 
   1921 /*
   1922  *  Rewind the device
   1923  */
   1924 static int
   1925 st_rewind(struct st_softc *st, u_int immediate, int flags)
   1926 {
   1927 	struct scsi_rewind cmd;
   1928 	int error;
   1929 	int nmarks;
   1930 
   1931 	error = st_check_eod(st, FALSE, &nmarks, flags);
   1932 	if (error) {
   1933 		printf("%s: failed to write closing filemarks at "
   1934 		    "rewind, errno=%d\n", st->sc_dev.dv_xname, error);
   1935 		return (error);
   1936 	}
   1937 	st->flags &= ~ST_PER_ACTION;
   1938 
   1939 	/*
   1940 	 * ATAPI tapes always need immediate to be set
   1941 	 */
   1942 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
   1943 		immediate = SR_IMMED;
   1944 
   1945 	memset(&cmd, 0, sizeof(cmd));
   1946 	cmd.opcode = REWIND;
   1947 	cmd.byte2 = immediate;
   1948 
   1949 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1950 	    ST_RETRIES, immediate ? ST_CTL_TIME: ST_SPC_TIME, NULL, flags);
   1951 	if (error) {
   1952 		printf("%s: error %d trying to rewind\n",
   1953 		    st->sc_dev.dv_xname, error);
   1954 		/* lost position */
   1955 		st->fileno = st->blkno = -1;
   1956 	} else {
   1957 		st->fileno = st->blkno = 0;
   1958 	}
   1959 	return (error);
   1960 }
   1961 
   1962 static int
   1963 st_rdpos(struct st_softc *st, int hard, u_int32_t *blkptr)
   1964 {
   1965 	int error;
   1966 	u_int8_t posdata[20];
   1967 	struct scsi_tape_read_position cmd;
   1968 
   1969 	/*
   1970 	 * We try and flush any buffered writes here if we were writing
   1971 	 * and we're trying to get hardware block position. It eats
   1972 	 * up performance substantially, but I'm wary of drive firmware.
   1973 	 *
   1974 	 * I think that *logical* block position is probably okay-
   1975 	 * but hardware block position might have to wait for data
   1976 	 * to hit media to be valid. Caveat Emptor.
   1977 	 */
   1978 
   1979 	if (hard && (st->flags & ST_WRITTEN)) {
   1980 		/*
   1981 		 * First flush any pending writes...
   1982 		 */
   1983 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
   1984 		/*
   1985 		 * The latter case is for 'write protected' tapes
   1986 		 * which are too stupid to recognize a zero count
   1987 		 * for writing filemarks as a no-op.
   1988 		 */
   1989 		if (error != 0 && error != EACCES && error != EROFS)
   1990 			return (error);
   1991 	}
   1992 
   1993 	memset(&cmd, 0, sizeof(cmd));
   1994 	memset(&posdata, 0, sizeof(posdata));
   1995 	cmd.opcode = READ_POSITION;
   1996 	if (hard)
   1997 		cmd.byte1 = 1;
   1998 
   1999 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
   2000 	    (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
   2001 	    XS_CTL_SILENT | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
   2002 
   2003 	if (error == 0) {
   2004 #if	0
   2005 		printf("posdata:");
   2006 		for (hard = 0; hard < sizeof(posdata); hard++)
   2007 			printf("%02x ", posdata[hard] & 0xff);
   2008 		printf("\n");
   2009 #endif
   2010 		if (posdata[0] & 0x4)	/* Block Position Unknown */
   2011 			error = EINVAL;
   2012 		else
   2013 			*blkptr = _4btol(&posdata[4]);
   2014 	}
   2015 	return (error);
   2016 }
   2017 
   2018 static int
   2019 st_setpos(struct st_softc *st, int hard, u_int32_t *blkptr)
   2020 {
   2021 	int error;
   2022 	struct scsi_tape_locate cmd;
   2023 
   2024 	/*
   2025 	 * We used to try and flush any buffered writes here.
   2026 	 * Now we push this onto user applications to either
   2027 	 * flush the pending writes themselves (via a zero count
   2028 	 * WRITE FILEMARKS command) or they can trust their tape
   2029 	 * drive to do this correctly for them.
   2030 	 *
   2031 	 * There are very ugly performance limitations otherwise.
   2032 	 */
   2033 
   2034 	memset(&cmd, 0, sizeof(cmd));
   2035 	cmd.opcode = LOCATE;
   2036 	if (hard)
   2037 		cmd.byte2 = 1 << 2;
   2038 	_lto4b(*blkptr, cmd.blkaddr);
   2039 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   2040 	    ST_RETRIES, ST_SPC_TIME, NULL, 0);
   2041 	/*
   2042 	 * Note file && block number position now unknown (if
   2043 	 * these things ever start being maintained in this driver)
   2044 	 */
   2045 	st->fileno = st->blkno = -1;
   2046 	return (error);
   2047 }
   2048 
   2049 
   2050 /*
   2051  * Look at the returned sense and act on the error and determine
   2052  * the unix error number to pass back..., 0 (== report no error),
   2053  * -1 = retry the operation, -2 continue error processing.
   2054  */
   2055 static int
   2056 st_interpret_sense(struct scsipi_xfer *xs)
   2057 {
   2058 	struct scsipi_periph *periph = xs->xs_periph;
   2059 	struct scsi_sense_data *sense = &xs->sense.scsi_sense;
   2060 	struct buf *bp = xs->bp;
   2061 	struct st_softc *st = (void *)periph->periph_dev;
   2062 	int retval = EJUSTRETURN;
   2063 	int doprint = ((xs->xs_control & XS_CTL_SILENT) == 0);
   2064 	u_int8_t key;
   2065 	int32_t info;
   2066 
   2067 	/*
   2068 	 * If it isn't a extended or extended/deferred error, let
   2069 	 * the generic code handle it.
   2070 	 */
   2071 	if (SSD_RCODE(sense->response_code) != SSD_RCODE_CURRENT &&
   2072 	    SSD_RCODE(sense->response_code) != SSD_RCODE_DEFERRED)
   2073 		return (retval);
   2074 
   2075 	if (sense->response_code & SSD_RCODE_VALID)
   2076 		info = _4btol(sense->info);
   2077 	else
   2078 		info = (st->flags & ST_FIXEDBLOCKS) ?
   2079 		    xs->datalen / st->blksize : xs->datalen;
   2080 	key = SSD_SENSE_KEY(sense->flags);
   2081 	st->mt_erreg = key;
   2082 	st->asc = sense->asc;
   2083 	st->ascq = sense->ascq;
   2084 	st->mt_resid = (short) info;
   2085 
   2086 	if (key == SKEY_NOT_READY && st->asc == 0x4 && st->ascq == 0x1) {
   2087 		/* Not Ready, Logical Unit Is in Process Of Becoming Ready */
   2088 		if (!callout_pending(&periph->periph_callout))
   2089 			scsipi_periph_freeze(periph, 1);
   2090 		callout_reset(&periph->periph_callout,
   2091 		    hz, scsipi_periph_timed_thaw, periph);
   2092 		return (ERESTART);
   2093 	}
   2094 
   2095 	/*
   2096 	 * If the device is not open yet, let generic handle
   2097 	 */
   2098 	if ((periph->periph_flags & PERIPH_OPEN) == 0) {
   2099 		return (retval);
   2100 	}
   2101 
   2102 	xs->resid = info;
   2103 	if (st->flags & ST_FIXEDBLOCKS) {
   2104 		if (bp) {
   2105 			xs->resid *= st->blksize;
   2106 			st->last_io_resid = xs->resid;
   2107 		} else {
   2108 			st->last_ctl_resid = xs->resid;
   2109 		}
   2110 		if (key == SKEY_VOLUME_OVERFLOW) {
   2111 			st->flags |= ST_EIO_PENDING;
   2112 			if (bp)
   2113 				bp->b_resid = xs->resid;
   2114 		} else if (sense->flags & SSD_EOM) {
   2115 			if ((st->flags & ST_EARLYWARN) == 0)
   2116 				st->flags |= ST_EIO_PENDING;
   2117 			st->flags |= ST_EOM_PENDING;
   2118 			if (bp) {
   2119 #if 0
   2120 				bp->b_resid = xs->resid;
   2121 #else
   2122 				/*
   2123 				 * Grotesque as it seems, the few times
   2124 				 * I've actually seen a non-zero resid,
   2125 				 * the tape drive actually lied and had
   2126 				 * written all the data!
   2127 				 */
   2128 				bp->b_resid = 0;
   2129 #endif
   2130 			}
   2131 		}
   2132 		if (sense->flags & SSD_FILEMARK) {
   2133 			st->flags |= ST_AT_FILEMARK;
   2134 			if (bp)
   2135 				bp->b_resid = xs->resid;
   2136 			if (st->fileno != (daddr_t) -1) {
   2137 				st->fileno++;
   2138 				st->blkno = 0;
   2139 				st->flags |= ST_POSUPDATED;
   2140 			}
   2141 		}
   2142 		if (sense->flags & SSD_ILI) {
   2143 			st->flags |= ST_EIO_PENDING;
   2144 			if (bp)
   2145 				bp->b_resid = xs->resid;
   2146 			if (sense->response_code & SSD_RCODE_VALID &&
   2147 			    (xs->xs_control & XS_CTL_SILENT) == 0)
   2148 				printf("%s: block wrong size, %d blocks "
   2149 				    "residual\n", st->sc_dev.dv_xname, info);
   2150 
   2151 			/*
   2152 			 * This quirk code helps the drive read
   2153 			 * the first tape block, regardless of
   2154 			 * format.  That is required for these
   2155 			 * drives to return proper MODE SENSE
   2156 			 * information.
   2157 			 */
   2158 			if ((st->quirks & ST_Q_SENSE_HELP) &&
   2159 			    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
   2160 				st->blksize -= 512;
   2161 			else if ((st->flags & ST_POSUPDATED) == 0) {
   2162 				if (st->blkno != (daddr_t) -1) {
   2163 					st->blkno +=
   2164 					    (xs->datalen / st->blksize);
   2165 					st->flags |= ST_POSUPDATED;
   2166 				}
   2167 			}
   2168 		}
   2169 		/*
   2170 		 * If data wanted and no data was transferred, do it immediately
   2171 		 */
   2172 		if (xs->datalen && xs->resid >= xs->datalen) {
   2173 			if (st->flags & ST_EIO_PENDING)
   2174 				return (EIO);
   2175 			if (st->flags & ST_AT_FILEMARK) {
   2176 				if (bp)
   2177 					bp->b_resid = xs->resid;
   2178 				return (0);
   2179 			}
   2180 		}
   2181 	} else {		/* must be variable mode */
   2182 		if (bp) {
   2183 			st->last_io_resid = xs->resid;
   2184 		} else {
   2185 			st->last_ctl_resid = xs->resid;
   2186 		}
   2187 		if (sense->flags & SSD_EOM) {
   2188 			/*
   2189 			 * The current semantics of this
   2190 			 * driver requires EOM detection
   2191 			 * to return EIO unless early
   2192 			 * warning detection is enabled
   2193 			 * for variable mode (this is always
   2194 			 * on for fixed block mode).
   2195 			 */
   2196 			if (st->flags & ST_EARLYWARN) {
   2197 				st->flags |= ST_EOM_PENDING;
   2198 				retval = 0;
   2199 			} else {
   2200 				retval = EIO;
   2201 			}
   2202 
   2203 			/*
   2204 			 * If it's an unadorned EOM detection,
   2205 			 * suppress printing an error.
   2206 			 */
   2207 			if (key == SKEY_NO_SENSE) {
   2208 				doprint = 0;
   2209 			}
   2210 		} else if (sense->flags & SSD_FILEMARK) {
   2211 			retval = 0;
   2212 			if (st->fileno != (daddr_t) -1) {
   2213 				st->fileno++;
   2214 				st->blkno = 0;
   2215 				st->flags |= ST_POSUPDATED;
   2216 			}
   2217 		} else if (sense->flags & SSD_ILI) {
   2218 			if (info < 0) {
   2219 				/*
   2220 				 * The tape record was bigger than the read
   2221 				 * we issued.
   2222 				 */
   2223 				if ((xs->xs_control & XS_CTL_SILENT) == 0) {
   2224 					printf("%s: %d-byte tape record too big"
   2225 					    " for %d-byte user buffer\n",
   2226 					    st->sc_dev.dv_xname,
   2227 					    xs->datalen - info, xs->datalen);
   2228 				}
   2229 				retval = EIO;
   2230 			} else {
   2231 				retval = 0;
   2232 				if (st->blkno != (daddr_t) -1) {
   2233 					st->blkno++;
   2234 					st->flags |= ST_POSUPDATED;
   2235 				}
   2236 			}
   2237 		}
   2238 		if (bp)
   2239 			bp->b_resid = info;
   2240 	}
   2241 
   2242 #ifndef SCSIPI_DEBUG
   2243 	if (retval == 0 && key == SKEY_NO_SENSE)
   2244 		doprint = 0;
   2245 #endif
   2246 	if (key == SKEY_BLANK_CHECK) {
   2247 		/*
   2248 		 * This quirk code helps the drive read the
   2249 		 * first tape block, regardless of format.  That
   2250 		 * is required for these drives to return proper
   2251 		 * MODE SENSE information.
   2252 		 */
   2253 		if ((st->quirks & ST_Q_SENSE_HELP) &&
   2254 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
   2255 			/* still starting */
   2256 			st->blksize -= 512;
   2257 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
   2258 			st->flags |= ST_BLANK_READ;
   2259 			xs->resid = xs->datalen;
   2260 			if (bp) {
   2261 				bp->b_resid = xs->resid;
   2262 				/* return an EOF */
   2263 			}
   2264 			retval = 0;
   2265 			/* lost position */
   2266 			st->fileno = st->blkno = -1;
   2267 		}
   2268 	}
   2269 
   2270 	/*
   2271 	 * If generic sense processing will continue, we should not
   2272 	 * print sense info here.
   2273 	 */
   2274 	if (retval == EJUSTRETURN)
   2275 		doprint = 0;
   2276 
   2277 	if (doprint) {
   2278 #ifdef	SCSIVERBOSE
   2279 		scsipi_print_sense(xs, 0);
   2280 #else
   2281 		scsipi_printaddr(periph);
   2282 		printf("Sense Key 0x%02x", key);
   2283 		if ((sense->response_code & SSD_RCODE_VALID) != 0) {
   2284 			switch (key) {
   2285 			case SKEY_NOT_READY:
   2286 			case SKEY_ILLEGAL_REQUEST:
   2287 			case SKEY_UNIT_ATTENTION:
   2288 			case SKEY_DATA_PROTECT:
   2289 				break;
   2290 			case SKEY_VOLUME_OVERFLOW:
   2291 			case SKEY_BLANK_CHECK:
   2292 				printf(", requested size: %d (decimal)", info);
   2293 				break;
   2294 			case SKEY_ABORTED_COMMAND:
   2295 				if (xs->xs_retries)
   2296 					printf(", retrying");
   2297 				printf(", cmd 0x%x, info 0x%x",
   2298 				    xs->cmd->opcode, info);
   2299 				break;
   2300 			default:
   2301 				printf(", info = %d (decimal)", info);
   2302 			}
   2303 		}
   2304 		if (sense->extra_len != 0) {
   2305 			int n;
   2306 			printf(", data =");
   2307 			for (n = 0; n < sense->extra_len; n++)
   2308 				printf(" %02x", sense->csi[n]);
   2309 		}
   2310 		printf("\n");
   2311 #endif
   2312 	}
   2313 	return (retval);
   2314 }
   2315 
   2316 /*
   2317  * The quirk here is that the drive returns some value to st_mode_sense
   2318  * incorrectly until the tape has actually passed by the head.
   2319  *
   2320  * The method is to set the drive to large fixed-block state (user-specified
   2321  * density and 1024-byte blocks), then read and rewind to get it to sense the
   2322  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
   2323  * work, as a last resort, try variable- length blocks.  The result will be
   2324  * the ability to do an accurate st_mode_sense.
   2325  *
   2326  * We know we can do a rewind because we just did a load, which implies rewind.
   2327  * Rewind seems preferable to space backward if we have a virgin tape.
   2328  *
   2329  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
   2330  * error processing, both part of st_interpret_sense.
   2331  */
   2332 static int
   2333 st_touch_tape(struct st_softc *st)
   2334 {
   2335 	char *bf;
   2336 	int readsize;
   2337 	int error;
   2338 
   2339 	bf = malloc(1024, M_TEMP, M_NOWAIT);
   2340 	if (bf == NULL)
   2341 		return (ENOMEM);
   2342 
   2343 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
   2344 		goto bad;
   2345 
   2346 	/*
   2347 	 * If the block size is already known from the
   2348 	 * sense data, use it. Else start probing at 1024.
   2349 	 */
   2350 	if (st->media_blksize > 0)
   2351 		st->blksize = st->media_blksize;
   2352 	else
   2353 		st->blksize = 1024;
   2354 
   2355 	do {
   2356 		switch (st->blksize) {
   2357 		case 512:
   2358 		case 1024:
   2359 			readsize = st->blksize;
   2360 			st->flags |= ST_FIXEDBLOCKS;
   2361 			break;
   2362 		default:
   2363 			readsize = 1;
   2364 			st->flags &= ~ST_FIXEDBLOCKS;
   2365 		}
   2366 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
   2367 		    != 0) {
   2368 			/*
   2369 			 * The device did not agree with the proposed
   2370 			 * block size. If we exhausted our options,
   2371 			 * return failure, else try another.
   2372 			 */
   2373 			if (readsize == 1)
   2374 				goto bad;
   2375 			st->blksize -= 512;
   2376 			continue;
   2377 		}
   2378 		st_read(st, bf, readsize, XS_CTL_SILENT);	/* XXX */
   2379 		if ((error = st_rewind(st, 0, 0)) != 0) {
   2380 bad:			free(bf, M_TEMP);
   2381 			return (error);
   2382 		}
   2383 	} while (readsize != 1 && readsize > st->blksize);
   2384 
   2385 	free(bf, M_TEMP);
   2386 	return (0);
   2387 }
   2388 
   2389 static int
   2390 stdump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
   2391 {
   2392 
   2393 	/* Not implemented. */
   2394 	return (ENXIO);
   2395 }
   2396