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      1 /*	$NetBSD: st.c,v 1.243 2022/02/23 21:54:41 andvar 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Originally written by Julian Elischer (julian (at) tfs.com)
     34  * for TRW Financial Systems for use under the MACH(2.5) operating system.
     35  *
     36  * TRW Financial Systems, in accordance with their agreement with Carnegie
     37  * Mellon University, makes this software available to CMU to distribute
     38  * or use in any manner that they see fit as long as this message is kept with
     39  * the software. For this reason TFS also grants any other persons or
     40  * organisations permission to use or modify this software.
     41  *
     42  * TFS supplies this software to be publicly redistributed
     43  * on the understanding that TFS is not responsible for the correct
     44  * functioning of this software in any circumstances.
     45  *
     46  * Ported to run under 386BSD by Julian Elischer (julian (at) tfs.com) Sept 1992
     47  * major changes by Julian Elischer (julian (at) jules.dialix.oz.au) May 1993
     48  *
     49  * A lot of rewhacking done by mjacob (mjacob (at) nas.nasa.gov).
     50  */
     51 
     52 #include <sys/cdefs.h>
     53 __KERNEL_RCSID(0, "$NetBSD: st.c,v 1.243 2022/02/23 21:54:41 andvar Exp $");
     54 
     55 #ifdef _KERNEL_OPT
     56 #include "opt_scsi.h"
     57 #endif
     58 
     59 #include <sys/param.h>
     60 #include <sys/systm.h>
     61 #include <sys/fcntl.h>
     62 #include <sys/errno.h>
     63 #include <sys/ioctl.h>
     64 #include <sys/malloc.h>
     65 #include <sys/buf.h>
     66 #include <sys/bufq.h>
     67 #include <sys/proc.h>
     68 #include <sys/mtio.h>
     69 #include <sys/device.h>
     70 #include <sys/conf.h>
     71 #include <sys/kernel.h>
     72 #include <sys/vnode.h>
     73 #include <sys/iostat.h>
     74 #include <sys/sysctl.h>
     75 
     76 #include <dev/scsipi/scsi_spc.h>
     77 #include <dev/scsipi/scsipi_all.h>
     78 #include <dev/scsipi/scsi_all.h>
     79 #include <dev/scsipi/scsi_tape.h>
     80 #include <dev/scsipi/scsipiconf.h>
     81 #include <dev/scsipi/scsipi_base.h>
     82 #include <dev/scsipi/stvar.h>
     83 
     84 /* Defines for device specific stuff */
     85 #define DEF_FIXED_BSIZE  512
     86 
     87 #define STMODE(z)	( minor(z)       & 0x03)
     88 #define STDSTY(z)	((minor(z) >> 2) & 0x03)
     89 #define STUNIT(z)	((minor(z) >> 4)       )
     90 #define STNMINOR	16
     91 
     92 #define NORMAL_MODE	0
     93 #define NOREW_MODE	1
     94 #define EJECT_MODE	2
     95 #define CTRL_MODE	3
     96 
     97 #ifndef		ST_MOUNT_DELAY
     98 #define		ST_MOUNT_DELAY		0
     99 #endif
    100 
    101 static dev_type_open(stopen);
    102 static dev_type_close(stclose);
    103 static dev_type_read(stread);
    104 static dev_type_write(stwrite);
    105 static dev_type_ioctl(stioctl);
    106 static dev_type_strategy(ststrategy);
    107 static dev_type_dump(stdump);
    108 
    109 const struct bdevsw st_bdevsw = {
    110 	.d_open = stopen,
    111 	.d_close = stclose,
    112 	.d_strategy = ststrategy,
    113 	.d_ioctl = stioctl,
    114 	.d_dump = stdump,
    115 	.d_psize = nosize,
    116 	.d_discard = nodiscard,
    117 	.d_flag = D_TAPE | D_MPSAFE
    118 };
    119 
    120 const struct cdevsw st_cdevsw = {
    121 	.d_open = stopen,
    122 	.d_close = stclose,
    123 	.d_read = stread,
    124 	.d_write = stwrite,
    125 	.d_ioctl = stioctl,
    126 	.d_stop = nostop,
    127 	.d_tty = notty,
    128 	.d_poll = nopoll,
    129 	.d_mmap = nommap,
    130 	.d_kqfilter = nokqfilter,
    131 	.d_discard = nodiscard,
    132 	.d_flag = D_TAPE | D_MPSAFE
    133 };
    134 
    135 /*
    136  * Define various devices that we know mis-behave in some way,
    137  * and note how they are bad, so we can correct for them
    138  */
    139 
    140 static const struct st_quirk_inquiry_pattern st_quirk_patterns[] = {
    141 	{{T_SEQUENTIAL, T_REMOV,
    142 	 "        ", "                ", "    "}, {0, 0, {
    143 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    144 		{ST_Q_FORCE_BLKSIZE, 512, QIC_24},	/* minor 4-7 */
    145 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_1600},	/* minor 8-11 */
    146 		{ST_Q_FORCE_BLKSIZE, 0, HALFINCH_6250}	/* minor 12-15 */
    147 	}}},
    148 	{{T_SEQUENTIAL, T_REMOV,
    149 	 "TANDBERG", " TDC 3600       ", ""},     {0, 12, {
    150 		{0, 0, 0},				/* minor 0-3 */
    151 		{ST_Q_FORCE_BLKSIZE, 0, QIC_525},	/* minor 4-7 */
    152 		{0, 0, QIC_150},			/* minor 8-11 */
    153 		{0, 0, QIC_120}				/* minor 12-15 */
    154 	}}},
    155  	{{T_SEQUENTIAL, T_REMOV,
    156  	 "TANDBERG", " TDC 3800       ", ""},     {0, 0, {
    157 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    158 		{0, 0, QIC_525},			/* minor 4-7 */
    159 		{0, 0, QIC_150},			/* minor 8-11 */
    160 		{0, 0, QIC_120}				/* minor 12-15 */
    161 	}}},
    162 	{{T_SEQUENTIAL, T_REMOV,
    163 	  "TANDBERG", " SLR5 4/8GB     ", ""},     {0, 0, {
    164 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 0-3 */
    165 		{0, 0, 0},				/* minor 4-7 */
    166 		{0, 0, 0},				/* minor 8-11 */
    167 		{0, 0, 0}				/* minor 12-15 */
    168 	}}},
    169 	/*
    170 	 * lacking a manual for the 4200, it's not clear what the
    171 	 * specific density codes should be- the device is a 2.5GB
    172 	 * capable QIC drive, those density codes aren't readily
    173 	 * available. The 'default' will just have to do.
    174 	 */
    175  	{{T_SEQUENTIAL, T_REMOV,
    176  	 "TANDBERG", " TDC 4200       ", ""},     {0, 0, {
    177 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    178 		{0, 0, QIC_525},			/* minor 4-7 */
    179 		{0, 0, QIC_150},			/* minor 8-11 */
    180 		{0, 0, QIC_120}				/* minor 12-15 */
    181 	}}},
    182 	/*
    183 	 * At least -005 and -007 need this.  I'll assume they all do unless I
    184 	 * hear otherwise.  - mycroft, 31MAR1994
    185 	 */
    186 	{{T_SEQUENTIAL, T_REMOV,
    187 	 "ARCHIVE ", "VIPER 2525 25462", ""},     {0, 0, {
    188 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    189 		{ST_Q_SENSE_HELP, 0, QIC_525},		/* minor 4-7 */
    190 		{0, 0, QIC_150},			/* minor 8-11 */
    191 		{0, 0, QIC_120}				/* minor 12-15 */
    192 	}}},
    193 	/*
    194 	 * One user reports that this works for his tape drive.  It probably
    195 	 * needs more work.  - mycroft, 09APR1994
    196 	 */
    197 	{{T_SEQUENTIAL, T_REMOV,
    198 	 "SANKYO  ", "CP525           ", ""},    {0, 0, {
    199 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    200 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
    201 		{0, 0, QIC_150},			/* minor 8-11 */
    202 		{0, 0, QIC_120}				/* minor 12-15 */
    203 	}}},
    204 	{{T_SEQUENTIAL, T_REMOV,
    205 	 "ANRITSU ", "DMT780          ", ""},     {0, 0, {
    206 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    207 		{ST_Q_FORCE_BLKSIZE, 512, QIC_525},	/* minor 4-7 */
    208 		{0, 0, QIC_150},			/* minor 8-11 */
    209 		{0, 0, QIC_120}				/* minor 12-15 */
    210 	}}},
    211 	{{T_SEQUENTIAL, T_REMOV,
    212 	 "ARCHIVE ", "VIPER 150  21247", ""},     {ST_Q_ERASE_NOIMM, 12, {
    213 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    214 		{0, 0, QIC_150},			/* minor 4-7 */
    215 		{0, 0, QIC_120},			/* minor 8-11 */
    216 		{0, 0, QIC_24}				/* minor 12-15 */
    217 	}}},
    218 	{{T_SEQUENTIAL, T_REMOV,
    219 	 "ARCHIVE ", "VIPER 150  21531", ""},     {ST_Q_ERASE_NOIMM, 12, {
    220 		{ST_Q_SENSE_HELP, 0, 0},		/* minor 0-3 */
    221 		{0, 0, QIC_150},			/* minor 4-7 */
    222 		{0, 0, QIC_120},			/* minor 8-11 */
    223 		{0, 0, QIC_24}				/* minor 12-15 */
    224 	}}},
    225 	{{T_SEQUENTIAL, T_REMOV,
    226 	 "WANGTEK ", "5099ES SCSI", ""},          {0, 0, {
    227 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    228 		{0, 0, QIC_11},				/* minor 4-7 */
    229 		{0, 0, QIC_24},				/* minor 8-11 */
    230 		{0, 0, QIC_24}				/* minor 12-15 */
    231 	}}},
    232 	{{T_SEQUENTIAL, T_REMOV,
    233 	 "WANGTEK ", "5150ES SCSI", ""},          {0, 0, {
    234 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    235 		{0, 0, QIC_24},				/* minor 4-7 */
    236 		{0, 0, QIC_120},			/* minor 8-11 */
    237 		{0, 0, QIC_150}				/* minor 12-15 */
    238 	}}},
    239 	{{T_SEQUENTIAL, T_REMOV,
    240 	 "WANGTEK ", "5525ES SCSI REV7", ""},     {0, 0, {
    241 		{0, 0, 0},				/* minor 0-3 */
    242 		{ST_Q_BLKSIZE, 0, QIC_525},		/* minor 4-7 */
    243 		{0, 0, QIC_150},			/* minor 8-11 */
    244 		{0, 0, QIC_120}				/* minor 12-15 */
    245 	}}},
    246 	{{T_SEQUENTIAL, T_REMOV,
    247 	 "WangDAT ", "Model 1300      ", ""},     {0, 0, {
    248 		{0, 0, 0},				/* minor 0-3 */
    249 		{ST_Q_FORCE_BLKSIZE, 512, DDS},		/* minor 4-7 */
    250 		{ST_Q_FORCE_BLKSIZE, 1024, DDS},	/* minor 8-11 */
    251 		{ST_Q_FORCE_BLKSIZE, 0, DDS}		/* minor 12-15 */
    252 	}}},
    253 	{{T_SEQUENTIAL, T_REMOV,
    254 	 "EXABYTE ", "EXB-8200        ", "263H"}, {0, 5, {
    255 		{0, 0, 0},				/* minor 0-3 */
    256 		{0, 0, 0},				/* minor 4-7 */
    257 		{0, 0, 0},				/* minor 8-11 */
    258 		{0, 0, 0}				/* minor 12-15 */
    259 	}}},
    260 	{{T_SEQUENTIAL, T_REMOV,
    261 	 "STK",      "9490",             ""},
    262 				{ST_Q_FORCE_BLKSIZE, 0, {
    263 		{0, 0, 0},				/* minor 0-3 */
    264 		{0, 0, 0},				/* minor 4-7 */
    265 		{0, 0, 0},				/* minor 8-11 */
    266 		{0, 0, 0}				/* minor 12-15 */
    267 	}}},
    268 	{{T_SEQUENTIAL, T_REMOV,
    269 	 "STK",      "SD-3",             ""},
    270 				{ST_Q_FORCE_BLKSIZE, 0, {
    271 		{0, 0, 0},				/* minor 0-3 */
    272 		{0, 0, 0},				/* minor 4-7 */
    273 		{0, 0, 0},				/* minor 8-11 */
    274 		{0, 0, 0}				/* minor 12-15 */
    275 	}}},
    276 	{{T_SEQUENTIAL, T_REMOV,
    277 	 "IBM",      "03590",            ""},     {ST_Q_IGNORE_LOADS, 0, {
    278 		{0, 0, 0},				/* minor 0-3 */
    279 		{0, 0, 0},				/* minor 4-7 */
    280 		{0, 0, 0},				/* minor 8-11 */
    281 		{0, 0, 0}				/* minor 12-15 */
    282 	}}},
    283 	{{T_SEQUENTIAL, T_REMOV,
    284 	 "HP      ", "T4000s          ", ""},     {ST_Q_UNIMODAL, 0, {
    285 		{0, 0, QIC_3095},			/* minor 0-3 */
    286 		{0, 0, QIC_3095},			/* minor 4-7 */
    287 		{0, 0, QIC_3095},			/* minor 8-11 */
    288 		{0, 0, QIC_3095},			/* minor 12-15 */
    289 	}}},
    290 #if 0
    291 	{{T_SEQUENTIAL, T_REMOV,
    292 	 "EXABYTE ", "EXB-8200        ", ""},     {0, 12, {
    293 		{0, 0, 0},				/* minor 0-3 */
    294 		{0, 0, 0},				/* minor 4-7 */
    295 		{0, 0, 0},				/* minor 8-11 */
    296 		{0, 0, 0}				/* minor 12-15 */
    297 	}}},
    298 #endif
    299 	{{T_SEQUENTIAL, T_REMOV,
    300 	 "TEAC    ", "MT-2ST/N50      ", ""},     {ST_Q_IGNORE_LOADS, 0, {
    301 		{0, 0, 0},			        /* minor 0-3 */
    302 		{0, 0, 0},			        /* minor 4-7 */
    303 		{0, 0, 0},			        /* minor 8-11 */
    304 		{0, 0, 0}			        /* minor 12-15 */
    305 	}}},
    306 	{{T_SEQUENTIAL, T_REMOV,
    307 	 "OnStream", "ADR50 Drive", ""},	  {ST_Q_UNIMODAL, 0, {
    308 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 0-3 */
    309 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 4-7 */
    310 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 8-11 */
    311 		{ST_Q_FORCE_BLKSIZE, 512, 0},	        /* minor 12-15 */
    312 	}}},
    313 	{{T_SEQUENTIAL, T_REMOV,
    314 	 "OnStream DI-30",      "",   "1.0"},  {ST_Q_NOFILEMARKS, 0, {
    315 		{0, 0, 0},                              /* minor 0-3 */
    316 		{0, 0, 0},                              /* minor 4-7 */
    317 		{0, 0, 0},                              /* minor 8-11 */
    318 		{0, 0, 0}                               /* minor 12-15 */
    319 	}}},
    320 	{{T_SEQUENTIAL, T_REMOV,
    321 	 "NCR H621", "0-STD-03-46F880 ", ""},     {ST_Q_NOPREVENT, 0, {
    322 		{0, 0, 0},			       /* minor 0-3 */
    323 		{0, 0, 0},			       /* minor 4-7 */
    324 		{0, 0, 0},			       /* minor 8-11 */
    325 		{0, 0, 0}			       /* minor 12-15 */
    326 	}}},
    327 	{{T_SEQUENTIAL, T_REMOV,
    328 	 "Seagate STT3401A", "hp0atxa", ""},	{0, 0, {
    329 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 0-3 */
    330 		{ST_Q_FORCE_BLKSIZE, 1024, 0},		/* minor 4-7 */
    331 		{ST_Q_FORCE_BLKSIZE, 512, 0},		/* minor 8-11 */
    332 		{ST_Q_FORCE_BLKSIZE, 512, 0}		/* minor 12-15 */
    333 	}}},
    334 };
    335 
    336 #define NOEJECT 0
    337 #define EJECT 1
    338 
    339 static void	st_identify_drive(struct st_softc *,
    340 		    struct scsipi_inquiry_pattern *);
    341 static void	st_loadquirks(struct st_softc *);
    342 static int	st_mount_tape(dev_t, int);
    343 static void	st_unmount(struct st_softc *, boolean);
    344 static int	st_decide_mode(struct st_softc *, boolean);
    345 static void	ststart(struct scsipi_periph *);
    346 static int	ststart1(struct scsipi_periph *, struct buf *, int *);
    347 static void	strestart(void *);
    348 static void	stdone(struct scsipi_xfer *, int);
    349 static int	st_read(struct st_softc *, char *, int, int);
    350 static int	st_space(struct st_softc *, int, u_int, int);
    351 static int	st_write_filemarks(struct st_softc *, int, int);
    352 static int	st_check_eod(struct st_softc *, boolean, int *, int);
    353 static int	st_load(struct st_softc *, u_int, int);
    354 static int	st_rewind(struct st_softc *, u_int, int);
    355 static int	st_interpret_sense(struct scsipi_xfer *);
    356 static int	st_touch_tape(struct st_softc *);
    357 static int	st_erase(struct st_softc *, int full, int flags);
    358 static void     st_updatefilepos(struct st_softc *);
    359 static int	st_rdpos(struct st_softc *, int, uint32_t *);
    360 static int	st_setpos(struct st_softc *, int, uint32_t *);
    361 
    362 static const struct scsipi_periphsw st_switch = {
    363 	st_interpret_sense,
    364 	ststart,
    365 	NULL,
    366 	stdone
    367 };
    368 
    369 #if defined(ST_ENABLE_EARLYWARN)
    370 #define	ST_INIT_FLAGS	ST_EARLYWARN
    371 #else
    372 #define	ST_INIT_FLAGS	0
    373 #endif
    374 
    375 /*
    376  * The routine called by the low level scsi routine when it discovers
    377  * A device suitable for this driver
    378  */
    379 void
    380 stattach(device_t parent, device_t self, void *aux)
    381 {
    382 	struct st_softc *st = device_private(self);
    383 	struct scsipibus_attach_args *sa = aux;
    384 	struct scsipi_periph *periph = sa->sa_periph;
    385 
    386 	SC_DEBUG(periph, SCSIPI_DB2, ("stattach: "));
    387 	st->sc_dev = self;
    388 
    389 	/* Store information needed to contact our base driver */
    390 	st->sc_periph = periph;
    391 	periph->periph_dev = st->sc_dev;
    392 	periph->periph_switch = &st_switch;
    393 
    394 	/* Set initial flags  */
    395 	st->flags = ST_INIT_FLAGS;
    396 
    397 	/* Set up the buf queues for this device */
    398 	bufq_alloc(&st->buf_queue, "fcfs", 0);
    399 	bufq_alloc(&st->buf_defer, "fcfs", 0);
    400 	callout_init(&st->sc_callout, 0);
    401 	mutex_init(&st->sc_iolock, MUTEX_DEFAULT, IPL_VM);
    402 
    403 	/*
    404 	 * Check if the drive is a known criminal and take
    405 	 * Any steps needed to bring it into line
    406 	 */
    407 	st_identify_drive(st, &sa->sa_inqbuf);
    408 	aprint_naive("\n");
    409 	aprint_normal("\n");
    410 	/* Use the subdriver to request information regarding the drive.  */
    411 	aprint_normal_dev(self, "%s", st->quirkdata ? "quirks apply, " : "");
    412 	if (scsipi_test_unit_ready(periph,
    413 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE) ||
    414 	    st->ops(st, ST_OPS_MODESENSE,
    415 	    XS_CTL_DISCOVERY | XS_CTL_SILENT | XS_CTL_IGNORE_MEDIA_CHANGE))
    416 		aprint_normal("drive empty\n");
    417 	else {
    418 		aprint_normal("density code %d, ", st->media_density);
    419 		if (st->media_blksize > 0)
    420 			aprint_normal("%d-byte", st->media_blksize);
    421 		else
    422 			aprint_normal("variable");
    423 		aprint_normal(" blocks, write-%s\n",
    424 		    (st->flags & ST_READONLY) ? "protected" : "enabled");
    425 	}
    426 
    427 	st->stats = iostat_alloc(IOSTAT_TAPE, parent,
    428 	    device_xname(st->sc_dev));
    429 
    430 	rnd_attach_source(&st->rnd_source, device_xname(st->sc_dev),
    431 	    RND_TYPE_TAPE, RND_FLAG_DEFAULT);
    432 }
    433 
    434 int
    435 stdetach(device_t self, int flags)
    436 {
    437 	struct st_softc *st = device_private(self);
    438 	struct scsipi_periph *periph = st->sc_periph;
    439 	struct scsipi_channel *chan = periph->periph_channel;
    440 	int bmaj, cmaj, mn;
    441 
    442 	/* locate the major number */
    443 	bmaj = bdevsw_lookup_major(&st_bdevsw);
    444 	cmaj = cdevsw_lookup_major(&st_cdevsw);
    445 
    446 	/* kill any pending restart */
    447 	callout_halt(&st->sc_callout, NULL);
    448 
    449 	mutex_enter(chan_mtx(chan));
    450 
    451 	/* Kill off any queued buffers. */
    452 	bufq_drain(st->buf_defer);
    453 	bufq_drain(st->buf_queue);
    454 
    455 	/* Kill off any pending commands. */
    456 	scsipi_kill_pending(st->sc_periph);
    457 
    458 	mutex_exit(chan_mtx(chan));
    459 
    460 	bufq_free(st->buf_defer);
    461 	bufq_free(st->buf_queue);
    462 	mutex_destroy(&st->sc_iolock);
    463 
    464 	/* Nuke the vnodes for any open instances */
    465 	mn = STUNIT(device_unit(self));
    466 	vdevgone(bmaj, mn, mn+STNMINOR-1, VBLK);
    467 	vdevgone(cmaj, mn, mn+STNMINOR-1, VCHR);
    468 
    469 	iostat_free(st->stats);
    470 
    471 	/* Unhook the entropy source. */
    472 	rnd_detach_source(&st->rnd_source);
    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 		KASSERT(st->page_0_size <= MAX_PAGE_0_SIZE);
    497 		st_loadquirks(st);
    498 	}
    499 }
    500 
    501 /*
    502  * initialise the subdevices to the default (QUIRK) state.
    503  * this will remove any setting made by the system operator or previous
    504  * operations.
    505  */
    506 static void
    507 st_loadquirks(struct st_softc *st)
    508 {
    509 	const struct	modes *mode;
    510 	struct	modes *mode2;
    511 	int i;
    512 
    513 	mode = st->quirkdata->modes;
    514 	mode2 = st->modes;
    515 	for (i = 0; i < 4; i++) {
    516 		memset(mode2, 0, sizeof(struct modes));
    517 		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK |
    518 		    DENSITY_SET_BY_QUIRK | BLKSIZE_SET_BY_USER |
    519 		    DENSITY_SET_BY_USER);
    520 		if ((mode->quirks | st->drive_quirks) & ST_Q_FORCE_BLKSIZE) {
    521 			mode2->blksize = mode->blksize;
    522 			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
    523 		}
    524 		if (mode->density) {
    525 			mode2->density = mode->density;
    526 			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
    527 		}
    528 		mode2->quirks |= mode->quirks;
    529 		mode++;
    530 		mode2++;
    531 	}
    532 }
    533 
    534 /* open the device. */
    535 static int
    536 stopen(dev_t dev, int flags, int mode, struct lwp *l)
    537 {
    538 	u_int stmode, dsty;
    539 	int error, sflags, unit, tries, ntries;
    540 	struct st_softc *st;
    541 	struct scsipi_periph *periph;
    542 	struct scsipi_adapter *adapt;
    543 
    544 	unit = STUNIT(dev);
    545 	st = device_lookup_private(&st_cd, unit);
    546 	if (st == NULL)
    547 		return ENXIO;
    548 
    549 	stmode = STMODE(dev);
    550 	dsty = STDSTY(dev);
    551 
    552 	periph = st->sc_periph;
    553 	adapt = periph->periph_channel->chan_adapter;
    554 
    555 	SC_DEBUG(periph, SCSIPI_DB1,
    556 	    ("open: dev=0x%"PRIx64" (unit %d (of %d))\n", dev, unit,
    557 	    st_cd.cd_ndevs));
    558 
    559 	/* Only allow one at a time */
    560 	if (periph->periph_flags & PERIPH_OPEN) {
    561 		aprint_error_dev(st->sc_dev, "already open\n");
    562 		return EBUSY;
    563 	}
    564 
    565 	if ((error = scsipi_adapter_addref(adapt)) != 0)
    566 		return error;
    567 
    568 	/* clear any latched errors. */
    569 	st->mt_resid = 0;
    570 	st->mt_erreg = 0;
    571 	st->asc = 0;
    572 	st->ascq = 0;
    573 
    574 	/*
    575 	 * Catch any unit attention errors. Be silent about this
    576 	 * unless we're already mounted. We ignore media change
    577 	 * if we're in control mode or not mounted yet.
    578 	 */
    579 	if ((st->flags & ST_MOUNTED) == 0 || stmode == CTRL_MODE) {
    580 #ifdef SCSIDEBUG
    581 		sflags = XS_CTL_IGNORE_MEDIA_CHANGE;
    582 #else
    583 		sflags = XS_CTL_SILENT|XS_CTL_IGNORE_MEDIA_CHANGE;
    584 #endif
    585 	} else
    586 		sflags = 0;
    587 
    588 	/*
    589 	 * If we're already mounted or we aren't configured for
    590 	 * a mount delay, only try a test unit ready once. Otherwise,
    591 	 * try up to ST_MOUNT_DELAY times with a rest interval of
    592 	 * one second between each try.
    593 	 */
    594 	if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0)
    595 		ntries = 1;
    596 	else
    597 		ntries = ST_MOUNT_DELAY;
    598 
    599 	for (error = tries = 0; tries < ntries; tries++) {
    600 		int slpintr, oflags;
    601 
    602 		/*
    603 		 * If we had no error, or we're opening the control mode
    604 		 * device, we jump out right away.
    605 		 */
    606 		error = scsipi_test_unit_ready(periph, sflags);
    607 		if (error == 0 || stmode == CTRL_MODE)
    608 			break;
    609 
    610 		/*
    611 		 * We had an error.
    612 		 *
    613 		 * If we're already mounted or we aren't configured for
    614 		 * a mount delay, or the error isn't a NOT READY error,
    615 		 * skip to the error exit now.
    616 		 */
    617 		if ((st->flags & ST_MOUNTED) || ST_MOUNT_DELAY == 0 ||
    618 		    (st->mt_key != SKEY_NOT_READY)) {
    619 			device_printf(st->sc_dev,
    620 				      "mount error (sense key=%d) - "
    621 				      "terminating mount session\n",
    622 				      st->mt_key);
    623 			/*
    624 			 * the following should not trigger unless
    625 			 * something serious happened while the device
    626 			 * was open (PREVENT MEDIUM REMOVAL in effect)
    627 			 */
    628 			if (st->flags & ST_WRITTEN &&
    629 			    st->mt_key == SKEY_UNIT_ATTENTION) {
    630 				/*
    631 				 * device / media state may have changed
    632 				 * refrain from writing missing file marks
    633 				 * onto potentially newly inserted/formatted
    634 				 * media (e. g. emergency EJECT/RESET/etc.)
    635 				 */
    636 				st->flags &= ~(ST_WRITTEN|ST_FM_WRITTEN);
    637 
    638 				device_printf(st->sc_dev,
    639                                     "CAUTION: file marks/data may be missing"
    640                                     " - ASC = 0x%02x, ASCQ = 0x%02x\n",
    641 					      st->asc, st->ascq);
    642 			}
    643 			goto bad;
    644 		}
    645 
    646 		/* clear any latched errors. */
    647 		st->mt_resid = 0;
    648 		st->mt_erreg = 0;
    649 		st->asc = 0;
    650 		st->ascq = 0;
    651 
    652 		/*
    653 		 * Fake that we have the device open so
    654 		 * we block other apps from getting in.
    655 		 */
    656 		oflags = periph->periph_flags;
    657 		periph->periph_flags |= PERIPH_OPEN;
    658 
    659 		slpintr = kpause("stload", true, hz, NULL);
    660 
    661 		periph->periph_flags = oflags;	/* restore flags */
    662 		if (slpintr != 0 && slpintr != EWOULDBLOCK) {
    663 			device_printf(st->sc_dev, "load interrupted\n");
    664 			goto bad;
    665 		}
    666 	}
    667 
    668 	/*
    669 	 * If the mode is 3 (e.g. minor = 3,7,11,15) then the device has
    670 	 * been opened to set defaults and perform other, usually non-I/O
    671 	 * related, operations. In this case, do a quick check to see
    672 	 * whether the unit actually had a tape loaded (this will be known
    673 	 * as to whether or not we got a NOT READY for the above
    674 	 * unit attention). If a tape is there, go do a mount sequence.
    675 	 */
    676 	if (stmode == CTRL_MODE &&
    677 	    st->mt_key != SKEY_NO_SENSE &&
    678 	    st->mt_key != SKEY_UNIT_ATTENTION) {
    679 		periph->periph_flags |= PERIPH_OPEN;
    680 		return 0;
    681 	}
    682 
    683 	/*
    684 	 * If we get this far and had an error set, that means we failed
    685 	 * to pass the 'test unit ready' test for the non-controlmode device,
    686 	 * so we bounce the open.
    687 	 */
    688 	if (error)
    689 		return error;
    690 
    691 	/* Else, we're now committed to saying we're open. */
    692 	periph->periph_flags |= PERIPH_OPEN; /* unit attn are now errors */
    693 
    694 	/*
    695 	 * If it's a different mode, or if the media has been
    696 	 * invalidated, unmount the tape from the previous
    697 	 * session but continue with open processing
    698 	 */
    699 	if (st->last_dsty != dsty ||
    700 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
    701 		st_unmount(st, NOEJECT);
    702 
    703 	/*
    704 	 * If we are not mounted, then we should start a new
    705 	 * mount session.
    706 	 */
    707 	if (!(st->flags & ST_MOUNTED)) {
    708 		if ((error = st_mount_tape(dev, flags)) != 0)
    709 			goto bad;
    710 		st->last_dsty = dsty;
    711 	}
    712 	if (!(st->quirks & ST_Q_NOPREVENT)) {
    713 		scsipi_prevent(periph, SPAMR_PREVENT_DT,
    714 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
    715 	}
    716 
    717 	SC_DEBUG(periph, SCSIPI_DB2, ("open complete\n"));
    718 	return 0;
    719 
    720 bad:
    721 	st_unmount(st, NOEJECT);
    722 	scsipi_adapter_delref(adapt);
    723 	periph->periph_flags &= ~PERIPH_OPEN;
    724 	return error;
    725 }
    726 
    727 static int
    728 stclose(dev_t dev, int flags, int mode, struct lwp *l)
    729 {
    730 	int stxx, error = 0;
    731 	struct st_softc *st = device_lookup_private(&st_cd, STUNIT(dev));
    732 	struct scsipi_periph *periph = st->sc_periph;
    733 	struct scsipi_adapter *adapt = periph->periph_channel->chan_adapter;
    734 
    735 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("closing\n"));
    736 
    737 	/*
    738 	 * Make sure that a tape opened in write-only mode will have
    739 	 * file marks written on it when closed, even if not written to.
    740 	 *
    741 	 * This is for SUN compatibility. Actually, the Sun way of
    742 	 * things is to:
    743 	 *
    744 	 *	only write filemarks if there are fmks to be written and
    745 	 *   		- open for write (possibly read/write)
    746 	 *		- the last operation was a write
    747 	 * 	or:
    748 	 *		- opened for wronly
    749 	 *		- no data was written (including filemarks)
    750 	 */
    751 
    752 	stxx = st->flags & (ST_WRITTEN | ST_FM_WRITTEN);
    753 	if ((flags & FWRITE) != 0) {
    754 		int nm = 0;
    755 #ifdef ST_SUNCOMPAT
    756 		/*
    757 		 * on request only
    758 		 * original compat code has not been working
    759 		 * since ~1998
    760 		 */
    761 		if ((flags & O_ACCMODE) == FWRITE && (stxx == 0)) {
    762 			st->flags |= ST_WRITTEN;
    763 			SC_DEBUG(st->sc_periph, SCSIPI_DB3,
    764 				 ("SUN compatibility: write FM(s) at close\n"));
    765 	        }
    766 #endif
    767 		error = st_check_eod(st, FALSE, &nm, 0);
    768 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
    769 			 ("wrote %d FM(s) at close error=%d\n", nm, error));
    770 	}
    771 
    772 	/* Allow robots to eject tape if needed.  */
    773 	if (!(st->quirks & ST_Q_NOPREVENT)) {
    774 		scsipi_prevent(periph, SPAMR_ALLOW,
    775 		    XS_CTL_IGNORE_ILLEGAL_REQUEST | XS_CTL_IGNORE_NOT_READY);
    776 	}
    777 
    778 	switch (STMODE(dev)) {
    779 	case NORMAL_MODE:
    780 		st_unmount(st, NOEJECT);
    781 		break;
    782 	case NOREW_MODE:
    783 	case CTRL_MODE:
    784 		/*
    785 		 * Leave mounted unless media seems to have been removed.
    786 		 *
    787 		 * Otherwise, if we're to terminate a tape with more than one
    788 		 * filemark [ and because we're not rewinding here ], backspace
    789 		 * one filemark so that later appends will see an unbroken
    790 		 * sequence of:
    791 		 *
    792 		 *	file - FMK - file - FMK ... file - FMK FMK (EOM)
    793 		 */
    794 		if ((periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
    795 			st_unmount(st, NOEJECT);
    796 		} else if (error == 0) {
    797 			/*
    798 			 * ST_WRITTEN was preserved from above.
    799 			 *
    800 			 * All we need to know here is:
    801 			 *
    802 			 *	Were we writing this tape and was the last
    803 			 *	operation a write?
    804 			 *
    805 			 *	Are there supposed to be 2FM at EOD?
    806 			 *
    807 			 * If both statements are true, then we backspace
    808 			 * one filemark.
    809 			 */
    810 			stxx &= ~ST_FM_WRITTEN;
    811 			stxx |= (st->flags & ST_2FM_AT_EOD);
    812 			if ((flags & FWRITE) != 0 &&
    813 			    (stxx == (ST_2FM_AT_EOD|ST_WRITTEN))) {
    814 				error = st_space(st, -1, SP_FILEMARKS, 0);
    815 				SC_DEBUG(st->sc_periph, SCSIPI_DB3, ("st_space(-1) error=%d\n", error));
    816 			} else {
    817 				SC_DEBUG(st->sc_periph, SCSIPI_DB3, ("no backspacing - flags = 0x%x, stxx=0x%x, st->flags=0x%x\n", flags, stxx, st->flags));
    818 			}
    819 		} else {
    820 			SC_DEBUG(st->sc_periph, SCSIPI_DB3, ("error %d from st_check_eod\n", error));
    821 		}
    822 
    823 		break;
    824 	case EJECT_MODE:
    825 		st_unmount(st, EJECT);
    826 		break;
    827 	}
    828 
    829 	KASSERTMSG((st->flags & ST_WRITTEN) == 0,
    830 		   "pending ST_WRITTEN flag NOT cleared (flags=0x%x)", st->flags);
    831 
    832 	scsipi_wait_drain(periph);
    833 
    834 	scsipi_adapter_delref(adapt);
    835 	periph->periph_flags &= ~PERIPH_OPEN;
    836 
    837 	return error;
    838 }
    839 
    840 /*
    841  * Start a new mount session.
    842  * Copy in all the default parameters from the selected device mode.
    843  * and try guess any that seem to be defaulted.
    844  */
    845 static int
    846 st_mount_tape(dev_t dev, int flags)
    847 {
    848 	int unit;
    849 	u_int dsty;
    850 	struct st_softc *st;
    851 	struct scsipi_periph *periph;
    852 	int error = 0;
    853 
    854 	unit = STUNIT(dev);
    855 	dsty = STDSTY(dev);
    856 	st = device_lookup_private(&st_cd, unit);
    857 	periph = st->sc_periph;
    858 
    859 	if (st->flags & ST_MOUNTED)
    860 		return 0;
    861 
    862 	SC_DEBUG(periph, SCSIPI_DB1, ("mounting\n "));
    863 	st->flags |= ST_NEW_MOUNT;
    864 	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
    865 	/*
    866 	 * If the media is new, then make sure we give it a chance to
    867 	 * to do a 'load' instruction.  (We assume it is new.)
    868 	 */
    869 	if ((error = st_load(st, LD_LOAD, XS_CTL_SILENT)) != 0)
    870 		return error;
    871 	/*
    872 	 * Throw another dummy instruction to catch
    873 	 * 'Unit attention' errors. Many drives give
    874 	 * these after doing a Load instruction (with
    875 	 * the MEDIUM MAY HAVE CHANGED asc/ascq).
    876 	 */
    877 	scsipi_test_unit_ready(periph, XS_CTL_SILENT);	/* XXX */
    878 
    879 	/*
    880 	 * Some devices can't tell you much until they have been
    881 	 * asked to look at the media. This quirk does this.
    882 	 */
    883 	if (st->quirks & ST_Q_SENSE_HELP)
    884 		if ((error = st_touch_tape(st)) != 0)
    885 			return error;
    886 	/*
    887 	 * Load the physical device parameters
    888 	 * loads: blkmin, blkmax
    889 	 */
    890 	if ((error = st->ops(st, ST_OPS_RBL, 0)) != 0)
    891 		return error;
    892 	/*
    893 	 * Load the media dependent parameters
    894 	 * includes: media_blksize,media_density,numblks
    895 	 * As we have a tape in, it should be reflected here.
    896 	 * If not you may need the "quirk" above.
    897 	 */
    898 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
    899 		return error;
    900 	/*
    901 	 * If we have gained a permanent density from somewhere,
    902 	 * then use it in preference to the one supplied by
    903 	 * default by the driver.
    904 	 */
    905 	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER))
    906 		st->density = st->modes[dsty].density;
    907 	else
    908 		st->density = st->media_density;
    909 	/*
    910 	 * If we have gained a permanent blocksize
    911 	 * then use it in preference to the one supplied by
    912 	 * default by the driver.
    913 	 */
    914 	st->flags &= ~ST_FIXEDBLOCKS;
    915 	if (st->modeflags[dsty] &
    916 	    (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
    917 		st->blksize = st->modes[dsty].blksize;
    918 		if (st->blksize)
    919 			st->flags |= ST_FIXEDBLOCKS;
    920 	} else {
    921 		if ((error = st_decide_mode(st, FALSE)) != 0)
    922 			return error;
    923 	}
    924 	if ((error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
    925 		/* ATAPI will return ENODEV for this, and this may be OK */
    926 		if (error != ENODEV) {
    927 			aprint_error_dev(st->sc_dev,
    928 			    "cannot set selected mode\n");
    929 			return error;
    930 		}
    931 	}
    932 	st->flags &= ~ST_NEW_MOUNT;
    933 	st->flags |= ST_MOUNTED;
    934 	periph->periph_flags |= PERIPH_MEDIA_LOADED;	/* move earlier? */
    935 	st->blkno = st->fileno = (daddr_t) 0;
    936 	return 0;
    937 }
    938 
    939 /*
    940  * End the present mount session.
    941  * Rewind, and optionally eject the tape.
    942  * Reset various flags to indicate that all new
    943  * operations require another mount operation
    944  */
    945 static void
    946 st_unmount(struct st_softc *st, boolean eject)
    947 {
    948 	struct scsipi_periph *periph = st->sc_periph;
    949 	int nmarks;
    950 
    951 	if ((st->flags & ST_MOUNTED) == 0)
    952 		return;
    953 	SC_DEBUG(periph, SCSIPI_DB1, ("unmounting\n"));
    954 	st_check_eod(st, FALSE, &nmarks, XS_CTL_IGNORE_NOT_READY);
    955 	st_rewind(st, 0, XS_CTL_IGNORE_NOT_READY);
    956 
    957 	/*
    958 	 * Section 9.3.3 of the SCSI specs states that a device shall return
    959 	 * the density value specified in the last successful MODE SELECT
    960 	 * after an unload operation, in case it is not able to
    961 	 * automatically determine the density of the new medium.
    962 	 *
    963 	 * So we instruct the device to use the default density, which will
    964 	 * prevent the use of stale density values (in particular,
    965 	 * in st_touch_tape().
    966 	 */
    967 	st->density = 0;
    968 	if (st->ops(st, ST_OPS_MODESELECT, 0) != 0) {
    969 		aprint_error_dev(st->sc_dev,
    970 		    "WARNING: cannot revert to default density\n");
    971 	}
    972 
    973 	if (eject) {
    974 		if (!(st->quirks & ST_Q_NOPREVENT)) {
    975 			scsipi_prevent(periph, SPAMR_ALLOW,
    976 			    XS_CTL_IGNORE_ILLEGAL_REQUEST |
    977 			    XS_CTL_IGNORE_NOT_READY);
    978 		}
    979 		st_load(st, LD_UNLOAD, XS_CTL_IGNORE_NOT_READY);
    980 		st->blkno = st->fileno = (daddr_t) -1;
    981 	} else {
    982 		st->blkno = st->fileno = (daddr_t) 0;
    983 	}
    984 	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
    985 	periph->periph_flags &= ~PERIPH_MEDIA_LOADED;
    986 }
    987 
    988 /*
    989  * Given all we know about the device, media, mode, 'quirks' and
    990  * initial operation, make a decision as to how we should be set
    991  * to run (regarding blocking and EOD marks)
    992  */
    993 int
    994 st_decide_mode(struct st_softc *st, boolean first_read)
    995 {
    996 
    997 	SC_DEBUG(st->sc_periph, SCSIPI_DB2, ("starting block mode decision\n"));
    998 
    999 	/*
   1000 	 * If the drive can only handle fixed-length blocks and only at
   1001 	 * one size, perhaps we should just do that.
   1002 	 */
   1003 	if (st->blkmin && (st->blkmin == st->blkmax)) {
   1004 		st->flags |= ST_FIXEDBLOCKS;
   1005 		st->blksize = st->blkmin;
   1006 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1007 		    ("blkmin == blkmax of %d\n", st->blkmin));
   1008 		goto done;
   1009 	}
   1010 	/*
   1011 	 * If the tape density mandates (or even suggests) use of fixed
   1012 	 * or variable-length blocks, comply.
   1013 	 */
   1014 	switch (st->density) {
   1015 	case HALFINCH_800:
   1016 	case HALFINCH_1600:
   1017 	case HALFINCH_6250:
   1018 	case DDS:
   1019 		st->flags &= ~ST_FIXEDBLOCKS;
   1020 		st->blksize = 0;
   1021 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1022 		    ("density specified variable\n"));
   1023 		goto done;
   1024 	case QIC_11:
   1025 	case QIC_24:
   1026 	case QIC_120:
   1027 	case QIC_150:
   1028 	case QIC_525:
   1029 	case QIC_1320:
   1030 	case QIC_3095:
   1031 	case QIC_3220:
   1032 		st->flags |= ST_FIXEDBLOCKS;
   1033 		if (st->media_blksize > 0)
   1034 			st->blksize = st->media_blksize;
   1035 		else
   1036 			st->blksize = DEF_FIXED_BSIZE;
   1037 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1038 		    ("density specified fixed\n"));
   1039 		goto done;
   1040 	}
   1041 	/*
   1042 	 * If we're about to read the tape, perhaps we should choose
   1043 	 * fixed or variable-length blocks and block size according to
   1044 	 * what the drive found on the tape.
   1045 	 */
   1046 	if (first_read &&
   1047 	    (!(st->quirks & ST_Q_BLKSIZE) || (st->media_blksize == 0) ||
   1048 	    (st->media_blksize == DEF_FIXED_BSIZE) ||
   1049 	    (st->media_blksize == 1024))) {
   1050 		if (st->media_blksize > 0)
   1051 			st->flags |= ST_FIXEDBLOCKS;
   1052 		else
   1053 			st->flags &= ~ST_FIXEDBLOCKS;
   1054 		st->blksize = st->media_blksize;
   1055 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1056 		    ("Used media_blksize of %d\n", st->media_blksize));
   1057 		goto done;
   1058 	}
   1059 	/*
   1060 	 * We're getting no hints from any direction.  Choose variable-
   1061 	 * length blocks arbitrarily.
   1062 	 */
   1063 	st->flags &= ~ST_FIXEDBLOCKS;
   1064 	st->blksize = 0;
   1065 	SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1066 	    ("Give up and default to variable mode\n"));
   1067 
   1068 done:
   1069 	/*
   1070 	 * Decide whether or not to write two file marks to signify end-
   1071 	 * of-data.  Make the decision as a function of density.  If
   1072 	 * the decision is not to use a second file mark, the SCSI BLANK
   1073 	 * CHECK condition code will be recognized as end-of-data when
   1074 	 * first read.
   1075 	 * (I think this should be a by-product of fixed/variable..julian)
   1076 	 */
   1077 	switch (st->density) {
   1078 /*      case 8 mm:   What is the SCSI density code for 8 mm, anyway? */
   1079 	case QIC_11:
   1080 	case QIC_24:
   1081 	case QIC_120:
   1082 	case QIC_150:
   1083 	case QIC_525:
   1084 	case QIC_1320:
   1085 	case QIC_3095:
   1086 	case QIC_3220:
   1087 		st->flags &= ~ST_2FM_AT_EOD;
   1088 		break;
   1089 	default:
   1090 		st->flags |= ST_2FM_AT_EOD;
   1091 	}
   1092 	return 0;
   1093 }
   1094 
   1095 /*
   1096  * Actually translate the requested transfer into
   1097  * one the physical driver can understand
   1098  * The transfer is described by a buf and will include
   1099  * only one physical transfer.
   1100  */
   1101 static void
   1102 ststrategy(struct buf *bp)
   1103 {
   1104 	struct st_softc *st = device_lookup_private(&st_cd, STUNIT(bp->b_dev));
   1105 	struct scsipi_periph *periph = st->sc_periph;
   1106 	struct scsipi_channel *chan = periph->periph_channel;
   1107 
   1108 	SC_DEBUG(periph, SCSIPI_DB1,
   1109 	    ("ststrategy %d bytes @ blk %" PRId64 "\n", bp->b_bcount,
   1110 	        bp->b_blkno));
   1111 	/* If it's a null transfer, return immediately */
   1112 	if (bp->b_bcount == 0)
   1113 		goto abort;
   1114 
   1115 	/* If offset is negative, error */
   1116 	if (bp->b_blkno < 0) {
   1117 		SC_DEBUG(periph, SCSIPI_DB3,
   1118 			 ("EINVAL: ststrategy negative blockcount %" PRId64 "\n", bp->b_blkno));
   1119 		bp->b_error = EINVAL;
   1120 		goto abort;
   1121 	}
   1122 
   1123 	/* Odd sized request on fixed drives are verboten */
   1124 	if (st->flags & ST_FIXEDBLOCKS) {
   1125 		if (bp->b_bcount % st->blksize) {
   1126 			aprint_error_dev(st->sc_dev, "bad request, must be multiple of %d\n",
   1127 			    st->blksize);
   1128 			bp->b_error = EIO;
   1129 			goto abort;
   1130 		}
   1131 	}
   1132 	/* as are out-of-range requests on variable drives. */
   1133 	else if (bp->b_bcount < st->blkmin ||
   1134 	    (st->blkmax && bp->b_bcount > st->blkmax)) {
   1135 		aprint_error_dev(st->sc_dev, "bad request, must be between %d and %d\n",
   1136 		    st->blkmin, st->blkmax);
   1137 		bp->b_error = EIO;
   1138 		goto abort;
   1139 	}
   1140 	mutex_enter(chan_mtx(chan));
   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(periph);
   1155 
   1156 	mutex_exit(chan_mtx(chan));
   1157 	return;
   1158 abort:
   1159 	/*
   1160 	 * Reset the residue because we didn't do anything,
   1161 	 * and send the buffer back as done.
   1162 	 */
   1163 	bp->b_resid = bp->b_bcount;
   1164 	biodone(bp);
   1165 	return;
   1166 }
   1167 
   1168 /*
   1169  * ststart looks to see if there is a buf waiting for the device
   1170  * and that the device is not already busy. If the device is busy,
   1171  * the request is deferred and retried on the next attempt.
   1172  * If both are true, ststart creates a scsi command to perform
   1173  * the transfer required.
   1174  *
   1175  * The transfer request will call scsipi_done on completion,
   1176  * which will in turn call this routine again so that the next
   1177  * queued transfer is performed. The bufs are queued by the
   1178  * strategy routine (ststrategy)
   1179  *
   1180  * This routine is also called after other non-queued requests
   1181  * have been made of the scsi driver, to ensure that the queue
   1182  * continues to be drained.
   1183  * ststart() is called with channel lock held
   1184  */
   1185 static int
   1186 ststart1(struct scsipi_periph *periph, struct buf *bp, int *errnop)
   1187 {
   1188 	struct st_softc *st = device_private(periph->periph_dev);
   1189         struct scsipi_channel *chan = periph->periph_channel;
   1190 	struct scsi_rw_tape cmd;
   1191 	struct scsipi_xfer *xs;
   1192 	int flags, error, complete = 1;
   1193 
   1194 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart1 "));
   1195 
   1196 	mutex_enter(chan_mtx(chan));
   1197 
   1198 	if (periph->periph_active >= periph->periph_openings) {
   1199 		error = EAGAIN;
   1200 		goto out;
   1201 	}
   1202 
   1203 	/* if a special awaits, let it proceed first */
   1204 	if (periph->periph_flags & PERIPH_WAITING) {
   1205 		periph->periph_flags &= ~PERIPH_WAITING;
   1206 		cv_broadcast(periph_cv_periph(periph));
   1207 		error = EAGAIN;
   1208 		goto out;
   1209 	}
   1210 
   1211 	/*
   1212 	 * If the device has been unmounted by the user
   1213 	 * then throw away all requests until done.
   1214 	 */
   1215 	if (__predict_false((st->flags & ST_MOUNTED) == 0 ||
   1216 	    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)) {
   1217 		error = EIO;
   1218 		goto out;
   1219 	}
   1220 
   1221 	/*
   1222 	 * only FIXEDBLOCK devices have pending I/O or space operations.
   1223 	 */
   1224 	if (st->flags & ST_FIXEDBLOCKS) {
   1225 		/*
   1226 		 * If we are at a filemark but have not reported it yet
   1227 		 * then we should report it now
   1228 		 */
   1229 		if (st->flags & ST_AT_FILEMARK) {
   1230 			if ((bp->b_flags & B_READ) == B_WRITE) {
   1231 				/*
   1232 				 * Handling of ST_AT_FILEMARK in
   1233 				 * st_space will fill in the right file
   1234 				 * mark count.
   1235 				 * Back up over filemark
   1236 				 */
   1237 				if (st_space(st, 0, SP_FILEMARKS, 0)) {
   1238 					error = EIO;
   1239 					goto out;
   1240 				}
   1241 			} else {
   1242 				error = 0;
   1243 				st->flags &= ~ST_AT_FILEMARK;
   1244 				goto out;
   1245 			}
   1246 		}
   1247 	}
   1248 	/*
   1249 	 * If we are at EOM but have not reported it
   1250 	 * yet then we should report it now.
   1251 	 */
   1252 	if (st->flags & (ST_EOM_PENDING|ST_EIO_PENDING)) {
   1253 		error = 0;
   1254 		if (st->flags & ST_EIO_PENDING)
   1255 			error = EIO;
   1256 		st->flags &= ~(ST_EOM_PENDING|ST_EIO_PENDING);
   1257 		goto out;
   1258 	}
   1259 
   1260 	/* Fill out the scsi command */
   1261 	memset(&cmd, 0, sizeof(cmd));
   1262 	flags = XS_CTL_NOSLEEP | XS_CTL_ASYNC;
   1263 	if ((bp->b_flags & B_READ) == B_WRITE) {
   1264 		cmd.opcode = WRITE;
   1265 		st->flags &= ~ST_FM_WRITTEN;
   1266 		flags |= XS_CTL_DATA_OUT;
   1267 	} else {
   1268 		cmd.opcode = READ;
   1269 		flags |= XS_CTL_DATA_IN;
   1270 	}
   1271 
   1272 	/*
   1273 	 * Handle "fixed-block-mode" tape drives by using the
   1274 	 * block count instead of the length.
   1275 	 */
   1276 	if (st->flags & ST_FIXEDBLOCKS) {
   1277 		cmd.byte2 |= SRW_FIXED;
   1278 		_lto3b(bp->b_bcount / st->blksize, cmd.len);
   1279 	} else
   1280 		_lto3b(bp->b_bcount, cmd.len);
   1281 
   1282 	/* Clear 'position updated' indicator */
   1283 	st->flags &= ~ST_POSUPDATED;
   1284 
   1285 	/* go ask the adapter to do all this for us */
   1286 	xs = scsipi_make_xs_locked(periph,
   1287 	    (struct scsipi_generic *)&cmd, sizeof(cmd),
   1288 	    (u_char *)bp->b_data, bp->b_bcount,
   1289 	    0, ST_IO_TIME, bp, flags);
   1290 	if (__predict_false(xs == NULL)) {
   1291 		/*
   1292 		 * out of memory. Keep this buffer in the queue, and
   1293 		 * retry later.
   1294 		 */
   1295 		callout_reset(&st->sc_callout, hz / 2, strestart,
   1296 		    periph);
   1297 		error = EAGAIN;
   1298 		goto out;
   1299 	}
   1300 
   1301 	error = scsipi_execute_xs(xs);
   1302 	/* with a scsipi_xfer preallocated, scsipi_command can't fail */
   1303 	KASSERT(error == 0);
   1304 	if (error == 0)
   1305 		complete = 0;
   1306 
   1307 out:
   1308 	mutex_exit(chan_mtx(chan));
   1309 
   1310 	*errnop = error;
   1311 	return complete;
   1312 }
   1313 
   1314 static void
   1315 ststart(struct scsipi_periph *periph)
   1316 {
   1317 	struct st_softc *st = device_private(periph->periph_dev);
   1318         struct scsipi_channel *chan = periph->periph_channel;
   1319 	struct buf *bp;
   1320 	int error, complete;
   1321 
   1322 	SC_DEBUG(periph, SCSIPI_DB2, ("ststart "));
   1323 
   1324 	mutex_exit(chan_mtx(chan));
   1325 	mutex_enter(&st->sc_iolock);
   1326 
   1327 	while ((bp = bufq_get(st->buf_defer)) != NULL
   1328 	       || (bp = bufq_get(st->buf_queue)) != NULL) {
   1329 
   1330 		iostat_busy(st->stats);
   1331 		mutex_exit(&st->sc_iolock);
   1332 
   1333 		complete = ststart1(periph, bp, &error);
   1334 
   1335 		mutex_enter(&st->sc_iolock);
   1336 		if (complete) {
   1337 			iostat_unbusy(st->stats, 0,
   1338 			              ((bp->b_flags & B_READ) == B_READ));
   1339 			if (error == EAGAIN) {
   1340 				bufq_put(st->buf_defer, bp);
   1341 				break;
   1342 			}
   1343 		}
   1344 		mutex_exit(&st->sc_iolock);
   1345 
   1346 		if (complete) {
   1347 			bp->b_error = error;
   1348 			bp->b_resid = bp->b_bcount;
   1349 			biodone(bp);
   1350 		}
   1351 
   1352 		mutex_enter(&st->sc_iolock);
   1353 	}
   1354 
   1355 	mutex_exit(&st->sc_iolock);
   1356 	mutex_enter(chan_mtx(chan));
   1357 }
   1358 
   1359 static void
   1360 strestart(void *v)
   1361 {
   1362 	struct scsipi_periph *periph = (struct scsipi_periph *)v;
   1363 	struct scsipi_channel *chan = periph->periph_channel;
   1364 
   1365 	mutex_enter(chan_mtx(chan));
   1366 	ststart((struct scsipi_periph *)v);
   1367 	mutex_exit(chan_mtx(chan));
   1368 }
   1369 
   1370 static void
   1371 stdone(struct scsipi_xfer *xs, int error)
   1372 {
   1373 	struct st_softc *st = device_private(xs->xs_periph->periph_dev);
   1374 	struct buf *bp = xs->bp;
   1375 
   1376 	if (bp) {
   1377 		bp->b_error = error;
   1378 		bp->b_resid = xs->resid;
   1379 		/*
   1380 		 * buggy device ? A SDLT320 can report an info
   1381 		 * field of 0x3de8000 on a Media Error/Write Error
   1382 		 * for this CBD: 0x0a 00 00 80 00 00
   1383 		 */
   1384 		if (bp->b_resid > bp->b_bcount || bp->b_resid < 0)
   1385 			bp->b_resid = bp->b_bcount;
   1386 
   1387 		mutex_enter(&st->sc_iolock);
   1388 
   1389 		if ((bp->b_flags & B_READ) == B_WRITE)
   1390 			st->flags |= ST_WRITTEN;
   1391 		else
   1392 			st->flags &= ~ST_WRITTEN;
   1393 
   1394 		iostat_unbusy(st->stats, bp->b_bcount,
   1395 			     ((bp->b_flags & B_READ) == B_READ));
   1396 
   1397 		if ((st->flags & ST_POSUPDATED) == 0) {
   1398 			if (error) {
   1399 				st->fileno = st->blkno = -1;
   1400 			} else if (st->blkno != -1) {
   1401 				if (st->flags & ST_FIXEDBLOCKS)
   1402 					st->blkno +=
   1403 					    (bp->b_bcount / st->blksize);
   1404 				else
   1405 					st->blkno++;
   1406 			}
   1407 		}
   1408 
   1409 		mutex_exit(&st->sc_iolock);
   1410 
   1411 		rnd_add_uint32(&st->rnd_source, bp->b_blkno);
   1412 
   1413 		biodone(bp);
   1414 	}
   1415 }
   1416 
   1417 static int
   1418 stread(dev_t dev, struct uio *uio, int iomode)
   1419 {
   1420 	struct st_softc *st = device_lookup_private(&st_cd, STUNIT(dev));
   1421 
   1422 	int r = physio(ststrategy, NULL, dev, B_READ,
   1423 		       st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio);
   1424 
   1425 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[stread: result=%d]\n", r));
   1426 
   1427 	return r;
   1428 }
   1429 
   1430 static int
   1431 stwrite(dev_t dev, struct uio *uio, int iomode)
   1432 {
   1433 	struct st_softc *st = device_lookup_private(&st_cd, STUNIT(dev));
   1434 
   1435 	int r = physio(ststrategy, NULL, dev, B_WRITE,
   1436 	    st->sc_periph->periph_channel->chan_adapter->adapt_minphys, uio);
   1437 
   1438 	SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[stwrite: result=%d]\n", r));
   1439 
   1440 	return r;
   1441 }
   1442 
   1443 /*
   1444  * Perform special action on behalf of the user;
   1445  * knows about the internals of this device
   1446  */
   1447 static int
   1448 stioctl(dev_t dev, u_long cmd, void *arg, int flag, struct lwp *l)
   1449 {
   1450 	int error = 0;
   1451 	int unit;
   1452 	int number, nmarks, dsty;
   1453 	int flags;
   1454 	struct st_softc *st;
   1455 	int hold_blksize;
   1456 	uint8_t hold_density;
   1457 	struct mtop *mt = (struct mtop *) arg;
   1458 
   1459 	/* Find the device that the user is talking about */
   1460 	flags = 0;		/* give error messages, act on errors etc. */
   1461 	unit = STUNIT(dev);
   1462 	dsty = STDSTY(dev);
   1463 	st = device_lookup_private(&st_cd, unit);
   1464 	hold_blksize = st->blksize;
   1465 	hold_density = st->density;
   1466 
   1467 	switch ((u_int)cmd) {
   1468 	case MTIOCGET: {
   1469 		struct mtget *g = (struct mtget *) arg;
   1470 		/*
   1471 		 * (to get the current state of READONLY)
   1472 		 */
   1473 		error = st->ops(st, ST_OPS_MODESENSE, XS_CTL_SILENT);
   1474 		if (error) {
   1475 			/*
   1476 			 * Ignore the error if in control mode;
   1477 			 * this is mandated by st(4).
   1478 			 */
   1479 			if (STMODE(dev) != CTRL_MODE)
   1480 				break;
   1481 			error = 0;
   1482 		}
   1483 		SC_DEBUG(st->sc_periph, SCSIPI_DB1, ("[ioctl: get status]\n"));
   1484 		memset(g, 0, sizeof(struct mtget));
   1485 		g->mt_type = MT_ISAR;	/* Ultrix compat *//*? */
   1486 		g->mt_blksiz = st->blksize;
   1487 		g->mt_density = st->density;
   1488 		g->mt_mblksiz[0] = st->modes[0].blksize;
   1489 		g->mt_mblksiz[1] = st->modes[1].blksize;
   1490 		g->mt_mblksiz[2] = st->modes[2].blksize;
   1491 		g->mt_mblksiz[3] = st->modes[3].blksize;
   1492 		g->mt_mdensity[0] = st->modes[0].density;
   1493 		g->mt_mdensity[1] = st->modes[1].density;
   1494 		g->mt_mdensity[2] = st->modes[2].density;
   1495 		g->mt_mdensity[3] = st->modes[3].density;
   1496 		g->mt_fileno = st->fileno;
   1497 		g->mt_blkno = st->blkno;
   1498 		if (st->flags & ST_READONLY)
   1499 			g->mt_dsreg |= MT_DS_RDONLY;
   1500 		if (st->flags & ST_MOUNTED)
   1501 			g->mt_dsreg |= MT_DS_MOUNTED;
   1502 		g->mt_resid = st->mt_resid;
   1503 		g->mt_erreg = st->mt_erreg;
   1504 		/*
   1505 		 * clear latched errors.
   1506 		 */
   1507 		st->mt_resid = 0;
   1508 		st->mt_erreg = 0;
   1509 		st->asc = 0;
   1510 		st->ascq = 0;
   1511 		break;
   1512 	}
   1513 	case MTIOCTOP: {
   1514 		SC_DEBUG(st->sc_periph, SCSIPI_DB1,
   1515 		    ("[ioctl: op=0x%x count=0x%x]\n", mt->mt_op,
   1516 			mt->mt_count));
   1517 
   1518 		/* compat: in U*x it is a short */
   1519 		number = mt->mt_count;
   1520 		switch ((short) (mt->mt_op)) {
   1521 		case MTWEOF:	/* write an end-of-file record */
   1522 			error = st_write_filemarks(st, number, flags);
   1523 			break;
   1524 		case MTBSF:	/* backward space file */
   1525 			number = -number;
   1526 			/* FALLTHROUGH */
   1527 		case MTFSF:	/* forward space file */
   1528 			error = st_check_eod(st, FALSE, &nmarks, flags);
   1529 			if (!error)
   1530 				error = st_space(st, number - nmarks,
   1531 				    SP_FILEMARKS, flags);
   1532 			break;
   1533 		case MTBSR:	/* backward space record */
   1534 			number = -number;
   1535 			/* FALLTHROUGH */
   1536 		case MTFSR:	/* forward space record */
   1537 			error = st_check_eod(st, true, &nmarks, flags);
   1538 			if (!error)
   1539 				error = st_space(st, number, SP_BLKS, flags);
   1540 			break;
   1541 		case MTREW:	/* rewind */
   1542 			error = st_rewind(st, 0, flags);
   1543 			break;
   1544 		case MTOFFL:	/* rewind and put the drive offline */
   1545 			st_unmount(st, EJECT);
   1546 			break;
   1547 		case MTNOP:	/* no operation, sets status only */
   1548 			break;
   1549 		case MTRETEN:	/* retension the tape */
   1550 			error = st_load(st, LD_RETENSION, flags);
   1551 			if (!error)
   1552 				error = st_load(st, LD_LOAD, flags);
   1553 			break;
   1554 		case MTEOM:	/* forward space to end of media */
   1555 			error = st_check_eod(st, FALSE, &nmarks, flags);
   1556 			if (!error)
   1557 				error = st_space(st, 1, SP_EOM, flags);
   1558 			break;
   1559 		case MTCACHE:	/* enable controller cache */
   1560 			st->flags &= ~ST_DONTBUFFER;
   1561 			goto try_new_value;
   1562 		case MTNOCACHE:	/* disable controller cache */
   1563 			st->flags |= ST_DONTBUFFER;
   1564 			goto try_new_value;
   1565 		case MTERASE:	/* erase volume */
   1566 			error = st_erase(st, number, flags);
   1567 			break;
   1568 		case MTSETBSIZ:	/* Set block size for device */
   1569 #ifdef	NOTYET
   1570 			if (!(st->flags & ST_NEW_MOUNT)) {
   1571 				uprintf("re-mount tape before changing "
   1572 				    "blocksize");
   1573 				error = EINVAL;
   1574 				break;
   1575 			}
   1576 #endif
   1577 			if (number == 0)
   1578 				st->flags &= ~ST_FIXEDBLOCKS;
   1579 			else {
   1580 				if ((st->blkmin || st->blkmax) &&
   1581 				    (number < st->blkmin ||
   1582 				    number > st->blkmax)) {
   1583 					error = EINVAL;
   1584 					break;
   1585 				}
   1586 				st->flags |= ST_FIXEDBLOCKS;
   1587 			}
   1588 			st->blksize = number;
   1589 			st->flags |= ST_BLOCK_SET;	/*XXX */
   1590 			goto try_new_value;
   1591 		case MTSETDNSTY:	/* Set density for device and mode */
   1592 			/*
   1593 			 * Any number >= 0 and <= 0xff is legal. Numbers
   1594 			 * above 0x80 are 'vendor unique'.
   1595 			 */
   1596 			if (number < 0 || number > 255) {
   1597 				error = EINVAL;
   1598 				break;
   1599 			} else
   1600 				st->density = number;
   1601 			goto try_new_value;
   1602 		case MTCMPRESS:
   1603 			error = st->ops(st, (number == 0) ?
   1604 			    ST_OPS_CMPRSS_OFF : ST_OPS_CMPRSS_ON,
   1605 			    XS_CTL_SILENT);
   1606 			break;
   1607 		case MTEWARN:
   1608 			if (number)
   1609 				st->flags |= ST_EARLYWARN;
   1610 			else
   1611 				st->flags &= ~ST_EARLYWARN;
   1612 			break;
   1613 
   1614 		default:
   1615 			error = EINVAL;
   1616 		}
   1617 		break;
   1618 	}
   1619 	case MTIOCIEOT:
   1620 	case MTIOCEEOT:
   1621 		break;
   1622 	case MTIOCRDSPOS:
   1623 		error = st_rdpos(st, 0, (uint32_t *)arg);
   1624 		break;
   1625 	case MTIOCRDHPOS:
   1626 		error = st_rdpos(st, 1, (uint32_t *)arg);
   1627 		break;
   1628 	case MTIOCSLOCATE:
   1629 		error = st_setpos(st, 0, (uint32_t *)arg);
   1630 		break;
   1631 	case MTIOCHLOCATE:
   1632 		error = st_setpos(st, 1, (uint32_t *)arg);
   1633 		break;
   1634 	default:
   1635 		error = scsipi_do_ioctl(st->sc_periph, dev, cmd, arg, flag, l);
   1636 		break;
   1637 	}
   1638 	return error;
   1639 
   1640 try_new_value:
   1641 	/*
   1642 	 * Check that the mode being asked for is aggreeable to the
   1643 	 * drive. If not, put it back the way it was.
   1644 	 *
   1645 	 * If in control mode, we can make (persistent) mode changes
   1646 	 * even if no medium is loaded (see st(4)).
   1647 	 */
   1648 	if ((STMODE(dev) != CTRL_MODE || (st->flags & ST_MOUNTED) != 0) &&
   1649 	    (error = st->ops(st, ST_OPS_MODESELECT, 0)) != 0) {
   1650 		/* put it back as it was */
   1651 		aprint_error_dev(st->sc_dev, "cannot set selected mode\n");
   1652 		st->density = hold_density;
   1653 		st->blksize = hold_blksize;
   1654 		if (st->blksize)
   1655 			st->flags |= ST_FIXEDBLOCKS;
   1656 		else
   1657 			st->flags &= ~ST_FIXEDBLOCKS;
   1658 		return error;
   1659 	}
   1660 	/*
   1661 	 * As the drive liked it, if we are setting a new default,
   1662 	 * set it into the structures as such.
   1663 	 *
   1664 	 * The means for deciding this are not finalised yet- but
   1665 	 * if the device was opened in Control Mode, the values
   1666 	 * are persistent now across mounts.
   1667 	 */
   1668 	if (STMODE(dev) == CTRL_MODE) {
   1669 		switch ((short) (mt->mt_op)) {
   1670 		case MTSETBSIZ:
   1671 			st->modes[dsty].blksize = st->blksize;
   1672 			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
   1673 			break;
   1674 		case MTSETDNSTY:
   1675 			st->modes[dsty].density = st->density;
   1676 			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
   1677 			break;
   1678 		}
   1679 	}
   1680 	return 0;
   1681 }
   1682 
   1683 /* Do a synchronous read. */
   1684 static int
   1685 st_read(struct st_softc *st, char *bf, int size, int flags)
   1686 {
   1687 	struct scsi_rw_tape cmd;
   1688 
   1689 	/* If it's a null transfer, return immediately */
   1690 	if (size == 0)
   1691 		return 0;
   1692 	memset(&cmd, 0, sizeof(cmd));
   1693 	cmd.opcode = READ;
   1694 	if (st->flags & ST_FIXEDBLOCKS) {
   1695 		cmd.byte2 |= SRW_FIXED;
   1696 		_lto3b(size / (st->blksize ? st->blksize : DEF_FIXED_BSIZE),
   1697 		    cmd.len);
   1698 	} else
   1699 		_lto3b(size, cmd.len);
   1700 	return scsipi_command(st->sc_periph,
   1701 	    (void *)&cmd, sizeof(cmd), (void *)bf, size, 0, ST_IO_TIME, NULL,
   1702 	    flags | XS_CTL_DATA_IN);
   1703 }
   1704 
   1705 /* issue an erase command */
   1706 static int
   1707 st_erase(struct st_softc *st, int full, int flags)
   1708 {
   1709 	int tmo;
   1710 	struct scsi_erase cmd;
   1711 
   1712 	/*
   1713 	 * Full erase means set LONG bit in erase command, which asks
   1714 	 * the drive to erase the entire unit.  Without this bit, we're
   1715 	 * asking the drive to write an erase gap.
   1716 	 */
   1717 	memset(&cmd, 0, sizeof(cmd));
   1718 	cmd.opcode = ERASE;
   1719 	if (full) {
   1720 		cmd.byte2 = SE_LONG;
   1721 		tmo = ST_SPC_TIME;
   1722 	} else
   1723 		tmo = ST_IO_TIME;
   1724 
   1725 	/*
   1726 	 * XXX We always do this asynchronously, for now, unless the device
   1727 	 * has the ST_Q_ERASE_NOIMM quirk.  How long should we wait if we
   1728 	 * want to (eventually) to it synchronously?
   1729 	 */
   1730 	if ((st->quirks & ST_Q_ERASE_NOIMM) == 0)
   1731 		cmd.byte2 |= SE_IMMED;
   1732 
   1733 	return scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1734 	    ST_RETRIES, tmo, NULL, flags);
   1735 }
   1736 
   1737 /* skip N blocks/filemarks/seq filemarks/eom */
   1738 static int
   1739 st_space(struct st_softc *st, int number, u_int what, int flags)
   1740 {
   1741 	struct scsi_space cmd;
   1742 	int error;
   1743 
   1744 	switch (what) {
   1745 	case SP_BLKS:
   1746 		if (st->flags & ST_PER_ACTION) {
   1747 			if (number > 0) {
   1748 				st->flags &= ~ST_PER_ACTION;
   1749 				return EIO;
   1750 			} else if (number < 0) {
   1751 				if (st->flags & ST_AT_FILEMARK) {
   1752 					/*
   1753 					 * Handling of ST_AT_FILEMARK
   1754 					 * in st_space will fill in the
   1755 					 * right file mark count.
   1756 					 */
   1757 					error = st_space(st, 0, SP_FILEMARKS,
   1758 					    flags);
   1759 					if (error)
   1760 						return error;
   1761 				}
   1762 				if (st->flags & ST_BLANK_READ) {
   1763 					st->flags &= ~ST_BLANK_READ;
   1764 					return EIO;
   1765 				}
   1766 				st->flags &= ~(ST_EIO_PENDING|ST_EOM_PENDING);
   1767 			}
   1768 		}
   1769 		break;
   1770 	case SP_FILEMARKS:
   1771 		if (st->flags & ST_EIO_PENDING) {
   1772 			if (number > 0) {
   1773 				/* pretend we just discovered the error */
   1774 				st->flags &= ~ST_EIO_PENDING;
   1775 				return EIO;
   1776 			} else if (number < 0) {
   1777 				/* back away from the error */
   1778 				st->flags &= ~ST_EIO_PENDING;
   1779 			}
   1780 		}
   1781 		if (st->flags & ST_AT_FILEMARK) {
   1782 			st->flags &= ~ST_AT_FILEMARK;
   1783 			number--;
   1784 		}
   1785 		if ((st->flags & ST_BLANK_READ) && (number < 0)) {
   1786 			/* back away from unwritten tape */
   1787 			st->flags &= ~ST_BLANK_READ;
   1788 			number++;	/* XXX dubious */
   1789 		}
   1790 		break;
   1791 	case SP_EOM:
   1792 		if (st->flags & ST_EOM_PENDING) {
   1793 			/* we're already there */
   1794 			st->flags &= ~ST_EOM_PENDING;
   1795 			return 0;
   1796 		}
   1797 		if (st->flags & ST_EIO_PENDING) {
   1798 			/* pretend we just discovered the error */
   1799 			st->flags &= ~ST_EIO_PENDING;
   1800 			return EIO;
   1801 		}
   1802 		if (st->flags & ST_AT_FILEMARK)
   1803 			st->flags &= ~ST_AT_FILEMARK;
   1804 		break;
   1805 	}
   1806 	if (number == 0)
   1807 		return 0;
   1808 
   1809 	memset(&cmd, 0, sizeof(cmd));
   1810 	cmd.opcode = SPACE;
   1811 	cmd.byte2 = what;
   1812 	_lto3b(number, cmd.number);
   1813 
   1814 	st->flags &= ~ST_POSUPDATED;
   1815 	st->last_ctl_resid = 0;
   1816 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1817 	    0, ST_SPC_TIME, NULL, flags);
   1818 
   1819 	if (error == 0 && (st->flags & ST_POSUPDATED) == 0) {
   1820 		number = number - st->last_ctl_resid;
   1821 		if (what == SP_BLKS) {
   1822 			if (st->blkno != -1)
   1823 				st->blkno += number;
   1824 		} else if (what == SP_FILEMARKS) {
   1825 			if (st->fileno != -1) {
   1826 				st->fileno += number;
   1827 				if (number > 0)
   1828 					st->blkno = 0;
   1829 				else if (number < 0)
   1830 					st->blkno = -1;
   1831 			}
   1832 		} else if (what == SP_EOM) {
   1833                         st_updatefilepos(st);
   1834 		}
   1835 	}
   1836 	return error;
   1837 }
   1838 
   1839 /*
   1840  * write N filemarks
   1841  */
   1842 static int
   1843 st_write_filemarks(struct st_softc *st, int number, int flags)
   1844 {
   1845 	int error;
   1846 	struct scsi_write_filemarks cmd;
   1847 
   1848 	/*
   1849 	 * It's hard to write a negative number of file marks.
   1850 	 * Don't try.
   1851 	 */
   1852 	if (number < 0) {
   1853 		SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   1854 			 ("EINVAL: st_write_filemarks not writing %d file marks\n", number));
   1855 		return EINVAL;
   1856 	}
   1857 
   1858 	switch (number) {
   1859 	case 0:		/* really a command to sync the drive's buffers */
   1860 		break;
   1861 	case 1:
   1862 		if (st->flags & ST_FM_WRITTEN)	/* already have one down */
   1863 			st->flags &= ~ST_WRITTEN;
   1864 		else
   1865 			st->flags |= ST_FM_WRITTEN;
   1866 		st->flags &= ~ST_PER_ACTION;
   1867 		break;
   1868 	default:
   1869 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
   1870 	}
   1871 
   1872 	memset(&cmd, 0, sizeof(cmd));
   1873 	cmd.opcode = WRITE_FILEMARKS;
   1874 	if (SCSIPI_BUSTYPE_TYPE(scsipi_periph_bustype(st->sc_periph)) ==
   1875 	    SCSIPI_BUSTYPE_ATAPI)
   1876 		cmd.byte2 = SR_IMMED;
   1877 	/*
   1878 	 * The ATAPI Onstream DI-30 doesn't support writing filemarks, but
   1879 	 * WRITE_FILEMARKS is still used to flush the buffer
   1880 	 */
   1881 	if ((st->quirks & ST_Q_NOFILEMARKS) == 0)
   1882 		_lto3b(number, cmd.number);
   1883 
   1884 	/* XXX WE NEED TO BE ABLE TO GET A RESIDIUAL XXX */
   1885 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1886 	    0, ST_IO_TIME * 4, NULL, flags);
   1887 	if (error == 0 && st->fileno != -1)
   1888 		st->fileno += number;
   1889 	return error;
   1890 }
   1891 
   1892 /*
   1893  * Make sure the right number of file marks is on tape if the
   1894  * tape has been written.  If the position argument is true,
   1895  * leave the tape positioned where it was originally.
   1896  *
   1897  * nmarks returns the number of marks to skip (or, if position
   1898  * true, which were skipped) to get back original position.
   1899  */
   1900 static int
   1901 st_check_eod(struct st_softc *st, boolean position, int *nmarks, int flags)
   1902 {
   1903 	int error;
   1904 
   1905 	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
   1906 	default:
   1907 		*nmarks = 0;
   1908 		return 0;
   1909 	case ST_WRITTEN:
   1910 	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
   1911 		*nmarks = 1;
   1912 		break;
   1913 	case ST_WRITTEN | ST_2FM_AT_EOD:
   1914 		*nmarks = 2;
   1915 	}
   1916 	error = st_write_filemarks(st, *nmarks, flags);
   1917 	if (position && !error)
   1918 		error = st_space(st, -*nmarks, SP_FILEMARKS, flags);
   1919 	return error;
   1920 }
   1921 
   1922 /* load/unload/retension */
   1923 static int
   1924 st_load(struct st_softc *st, u_int type, int flags)
   1925 {
   1926 	int error;
   1927 	struct scsi_load cmd;
   1928 
   1929 	if (type != LD_LOAD) {
   1930 		int nmarks;
   1931 
   1932 		error = st_check_eod(st, FALSE, &nmarks, flags);
   1933 		if (error) {
   1934 			aprint_error_dev(st->sc_dev,
   1935 			    "failed to write closing filemarks at "
   1936 			    "unload, errno=%d\n", error);
   1937 			return error;
   1938 		}
   1939 	}
   1940 	if (st->quirks & ST_Q_IGNORE_LOADS) {
   1941 		if (type == LD_LOAD)
   1942 			/*
   1943 			 * If we ignore loads, at least we should try a rewind.
   1944 			 */
   1945 			return st_rewind(st, 0, flags);
   1946 		/* otherwise, we should do what's asked of us */
   1947 	}
   1948 
   1949 	memset(&cmd, 0, sizeof(cmd));
   1950 	cmd.opcode = LOAD;
   1951 	if (SCSIPI_BUSTYPE_TYPE(scsipi_periph_bustype(st->sc_periph)) ==
   1952 	    SCSIPI_BUSTYPE_ATAPI)
   1953 		cmd.byte2 = SR_IMMED;
   1954 	cmd.how = type;
   1955 
   1956 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1957 	    ST_RETRIES, ST_SPC_TIME, NULL, flags);
   1958 	if (error) {
   1959 		aprint_error_dev(st->sc_dev, "error %d in st_load (op %d)\n",
   1960 		    error, type);
   1961 	}
   1962 	return error;
   1963 }
   1964 
   1965 /* Rewind the device */
   1966 static int
   1967 st_rewind(struct st_softc *st, u_int immediate, int flags)
   1968 {
   1969 	struct scsi_rewind cmd;
   1970 	int error;
   1971 	int nmarks;
   1972 	int timeout;
   1973 
   1974 	error = st_check_eod(st, FALSE, &nmarks, flags);
   1975 	if (error) {
   1976 		aprint_error_dev(st->sc_dev,
   1977 		    "failed to write closing filemarks at "
   1978 		    "rewind, errno=%d\n", error);
   1979 		return error;
   1980 	}
   1981 	st->flags &= ~ST_PER_ACTION;
   1982 
   1983 	/* If requestor asked for immediate response, set a short timeout */
   1984 	timeout = immediate ? ST_CTL_TIME : ST_SPC_TIME;
   1985 
   1986 	/* ATAPI tapes always need immediate to be set */
   1987 	if (scsipi_periph_bustype(st->sc_periph) == SCSIPI_BUSTYPE_ATAPI)
   1988 		immediate = SR_IMMED;
   1989 
   1990 	memset(&cmd, 0, sizeof(cmd));
   1991 	cmd.opcode = REWIND;
   1992 	cmd.byte2 = immediate;
   1993 
   1994 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   1995 	    ST_RETRIES, timeout, NULL, flags);
   1996 	if (error) {
   1997 		aprint_error_dev(st->sc_dev, "error %d trying to rewind\n",
   1998 		    error);
   1999 		/* lost position */
   2000 		st->fileno = st->blkno = -1;
   2001 	} else
   2002 		st->fileno = st->blkno = 0;
   2003 	return error;
   2004 }
   2005 
   2006 static void
   2007 st_updatefilepos(struct st_softc *st)
   2008 {
   2009         int error;
   2010         uint8_t posdata[32];
   2011         struct scsi_tape_read_position cmd;
   2012 
   2013         memset(&cmd, 0, sizeof(cmd));
   2014         memset(&posdata, 0, sizeof(posdata));
   2015         cmd.opcode = READ_POSITION;
   2016         cmd.byte1 = 6;  /* service action: LONG FORM */
   2017 
   2018         error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
   2019             (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
   2020             XS_CTL_SILENT | XS_CTL_DATA_IN);
   2021 
   2022         if (error == 0) {
   2023 #ifdef SCSIPI_DEBUG
   2024                 if (st->sc_periph->periph_dbflags & SCSIPI_DB3) {
   2025                         int hard;
   2026 
   2027                         printf("posdata: ");
   2028                         for (hard = 0; hard < sizeof(posdata); hard++)
   2029                                 printf("%02x ", posdata[hard] & 0xff);
   2030                         printf("\n");
   2031                 }
   2032 #endif
   2033                 if (posdata[0] & 0xC) { /* Block|Mark Position Unknown */
   2034                         SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   2035                                  ("st_updatefilepos block/mark position unknown (0x%02x)\n",
   2036                                   posdata[0]));
   2037                 } else {
   2038                         st->fileno = _8btol(&posdata[16]);
   2039                         st->blkno = 0;
   2040                         SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   2041                                  ("st_updatefilepos file position %"PRId64"\n",
   2042                                   st->fileno));
   2043                         return;
   2044                 }
   2045         } else {
   2046                 SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   2047                          ("st_updatefilepos READ POSITION(LONG_FORM) failed (error=%d)\n",
   2048                           error));
   2049         }
   2050         st->fileno = -1;
   2051         st->blkno = -1;
   2052 }
   2053 
   2054 static int
   2055 st_rdpos(struct st_softc *st, int hard, uint32_t *blkptr)
   2056 {
   2057 	int error;
   2058 	uint8_t posdata[20];
   2059 	struct scsi_tape_read_position cmd;
   2060 
   2061 	/*
   2062 	 * We try and flush any buffered writes here if we were writing
   2063 	 * and we're trying to get hardware block position. It eats
   2064 	 * up performance substantially, but I'm wary of drive firmware.
   2065 	 *
   2066 	 * I think that *logical* block position is probably okay-
   2067 	 * but hardware block position might have to wait for data
   2068 	 * to hit media to be valid. Caveat Emptor.
   2069 	 */
   2070 
   2071 	if (hard && (st->flags & ST_WRITTEN)) {
   2072 		/* First flush any pending writes... */
   2073 		error = st_write_filemarks(st, 0, XS_CTL_SILENT);
   2074 		/*
   2075 		 * The latter case is for 'write protected' tapes
   2076 		 * which are too stupid to recognize a zero count
   2077 		 * for writing filemarks as a no-op.
   2078 		 */
   2079 		if (error != 0 && error != EACCES && error != EROFS)
   2080 			return error;
   2081 	}
   2082 
   2083 	memset(&cmd, 0, sizeof(cmd));
   2084 	memset(&posdata, 0, sizeof(posdata));
   2085 	cmd.opcode = READ_POSITION;
   2086 	if (hard)
   2087 		cmd.byte1 = 1;
   2088 
   2089 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd),
   2090 	    (void *)&posdata, sizeof(posdata), ST_RETRIES, ST_CTL_TIME, NULL,
   2091 	    XS_CTL_SILENT | XS_CTL_DATA_IN);
   2092 
   2093 	if (error == 0) {
   2094 #if	0
   2095 		printf("posdata:");
   2096 		for (hard = 0; hard < sizeof(posdata); hard++)
   2097 			printf("%02x ", posdata[hard] & 0xff);
   2098 		printf("\n");
   2099 #endif
   2100 		if (posdata[0] & 0x4) {	/* Block Position Unknown */
   2101 			SC_DEBUG(st->sc_periph, SCSIPI_DB3,
   2102 				 ("EINVAL: strdpos block position unknown\n"));
   2103 			error = EINVAL;
   2104 		}
   2105 		else
   2106 			*blkptr = _4btol(&posdata[4]);
   2107 	}
   2108 	return error;
   2109 }
   2110 
   2111 static int
   2112 st_setpos(struct st_softc *st, int hard, uint32_t *blkptr)
   2113 {
   2114 	int error;
   2115 	struct scsi_tape_locate cmd;
   2116 
   2117 	/*
   2118 	 * We used to try and flush any buffered writes here.
   2119 	 * Now we push this onto user applications to either
   2120 	 * flush the pending writes themselves (via a zero count
   2121 	 * WRITE FILEMARKS command) or they can trust their tape
   2122 	 * drive to do this correctly for them.
   2123 	 *
   2124 	 * There are very ugly performance limitations otherwise.
   2125 	 */
   2126 
   2127 	memset(&cmd, 0, sizeof(cmd));
   2128 	cmd.opcode = LOCATE;
   2129 	if (hard)
   2130 		cmd.byte2 = 1 << 2;
   2131 	_lto4b(*blkptr, cmd.blkaddr);
   2132 	error = scsipi_command(st->sc_periph, (void *)&cmd, sizeof(cmd), 0, 0,
   2133 	    ST_RETRIES, ST_SPC_TIME, NULL, 0);
   2134 	/*
   2135 	 * Note file && block number position now unknown (if
   2136 	 * these things ever start being maintained in this driver)
   2137 	 */
   2138 	st->fileno = st->blkno = -1;
   2139 	return error;
   2140 }
   2141 
   2142 
   2143 /*
   2144  * Look at the returned sense and act on the error and determine
   2145  * the unix error number to pass back..., 0 (== report no error),
   2146  * -1 = retry the operation, -2 continue error processing.
   2147  */
   2148 static int
   2149 st_interpret_sense(struct scsipi_xfer *xs)
   2150 {
   2151 	struct scsipi_periph *periph = xs->xs_periph;
   2152 	struct scsi_sense_data *sense = &xs->sense.scsi_sense;
   2153 	struct buf *bp = xs->bp;
   2154 	struct st_softc *st = device_private(periph->periph_dev);
   2155 	int retval = EJUSTRETURN;
   2156 	int doprint = ((xs->xs_control & XS_CTL_SILENT) == 0);
   2157 	uint8_t key;
   2158 	int32_t info;
   2159 
   2160 	/*
   2161 	 * If it isn't a extended or extended/deferred error, let
   2162 	 * the generic code handle it.
   2163 	 */
   2164 	if (SSD_RCODE(sense->response_code) != SSD_RCODE_CURRENT &&
   2165 	    SSD_RCODE(sense->response_code) != SSD_RCODE_DEFERRED)
   2166 		return retval;
   2167 
   2168 	if (sense->response_code & SSD_RCODE_VALID)
   2169 		info = _4btol(sense->info);
   2170 	else
   2171 		info = (st->flags & ST_FIXEDBLOCKS) ?
   2172 		    xs->datalen / st->blksize : xs->datalen;
   2173 	key = SSD_SENSE_KEY(sense->flags);
   2174 	st->mt_erreg = key;
   2175 	st->asc = sense->asc;
   2176 	st->ascq = sense->ascq;
   2177 	st->mt_resid = (short) info;
   2178 
   2179 	if (key == SKEY_NOT_READY && st->asc == 0x4 && st->ascq == 0x1) {
   2180 		/* Not Ready, Logical Unit Is in Process Of Becoming Ready */
   2181 		if (!callout_pending(&periph->periph_callout))
   2182 			scsipi_periph_freeze(periph, 1);
   2183 		callout_reset(&periph->periph_callout,
   2184 		    hz, scsipi_periph_timed_thaw, periph);
   2185 		return ERESTART;
   2186 	}
   2187 
   2188 	/* If the device is not open yet, let generic handle */
   2189 	if ((periph->periph_flags & PERIPH_OPEN) == 0)
   2190 		return retval;
   2191 
   2192 	xs->resid = info;
   2193 	if (st->flags & ST_FIXEDBLOCKS) {
   2194 		if (bp) {
   2195 			xs->resid *= st->blksize;
   2196 			st->last_io_resid = xs->resid;
   2197 		} else
   2198 			st->last_ctl_resid = xs->resid;
   2199 		if (key == SKEY_VOLUME_OVERFLOW) {
   2200 			st->flags |= ST_EIO_PENDING;
   2201 			if (bp)
   2202 				bp->b_resid = xs->resid;
   2203 		} else if (sense->flags & SSD_EOM) {
   2204 			if ((st->flags & ST_EARLYWARN) == 0)
   2205 				st->flags |= ST_EIO_PENDING;
   2206 			st->flags |= ST_EOM_PENDING;
   2207 			if (bp) {
   2208 #if 0
   2209 				bp->b_resid = xs->resid;
   2210 #else
   2211 				/*
   2212 				 * Grotesque as it seems, the few times
   2213 				 * I've actually seen a non-zero resid,
   2214 				 * the tape drive actually lied and had
   2215 				 * written all the data!
   2216 				 */
   2217 				bp->b_resid = 0;
   2218 #endif
   2219 			}
   2220 		}
   2221 		if (sense->flags & SSD_FILEMARK) {
   2222 			st->flags |= ST_AT_FILEMARK;
   2223 			if (bp)
   2224 				bp->b_resid = xs->resid;
   2225 			if (st->fileno != (daddr_t) -1) {
   2226 				st->fileno++;
   2227 				st->blkno = 0;
   2228 				st->flags |= ST_POSUPDATED;
   2229 			}
   2230 		}
   2231 		if (sense->flags & SSD_ILI) {
   2232 			st->flags |= ST_EIO_PENDING;
   2233 			if (bp)
   2234 				bp->b_resid = xs->resid;
   2235 			if (sense->response_code & SSD_RCODE_VALID &&
   2236 			    (xs->xs_control & XS_CTL_SILENT) == 0)
   2237 				aprint_error_dev(st->sc_dev,
   2238 				    "block wrong size, %d blocks residual\n",
   2239 				    info);
   2240 
   2241 			/*
   2242 			 * This quirk code helps the drive read
   2243 			 * the first tape block, regardless of
   2244 			 * format.  That is required for these
   2245 			 * drives to return proper MODE SENSE
   2246 			 * information.
   2247 			 */
   2248 			if ((st->quirks & ST_Q_SENSE_HELP) &&
   2249 			    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0)
   2250 				st->blksize -= 512;
   2251 			else if ((st->flags & ST_POSUPDATED) == 0) {
   2252 				if (st->blkno != (daddr_t) -1) {
   2253 					st->blkno +=
   2254 					    (xs->datalen / st->blksize);
   2255 					st->flags |= ST_POSUPDATED;
   2256 				}
   2257 			}
   2258 		}
   2259 		/*
   2260 		 * If data wanted and no data was transferred, do it immediately
   2261 		 */
   2262 		if (xs->datalen && xs->resid >= xs->datalen) {
   2263 			if (st->flags & ST_EIO_PENDING)
   2264 				return EIO;
   2265 			if (st->flags & ST_AT_FILEMARK) {
   2266 				if (bp)
   2267 					bp->b_resid = xs->resid;
   2268 				return 0;
   2269 			}
   2270 		}
   2271 	} else {		/* must be variable mode */
   2272 		if (bp)
   2273 			st->last_io_resid = xs->resid;
   2274 		else
   2275 			st->last_ctl_resid = xs->resid;
   2276 		if (sense->flags & SSD_EOM) {
   2277 			/*
   2278 			 * The current semantics of this
   2279 			 * driver requires EOM detection
   2280 			 * to return EIO unless early
   2281 			 * warning detection is enabled
   2282 			 * for variable mode (this is always
   2283 			 * on for fixed block mode).
   2284 			 */
   2285 			if (st->flags & ST_EARLYWARN) {
   2286 				st->flags |= ST_EOM_PENDING;
   2287 				retval = 0;
   2288 			} else {
   2289 				retval = EIO;
   2290 				/*
   2291 				 * If we return an error we can't claim to
   2292 				 * have transferred all data.
   2293 				 */
   2294 				if (xs->resid == 0)
   2295 					xs->resid = xs->datalen;
   2296 			}
   2297 
   2298 			/*
   2299 			 * If it's an unadorned EOM detection,
   2300 			 * suppress printing an error.
   2301 			 */
   2302 			if (key == SKEY_NO_SENSE) {
   2303 				doprint = 0;
   2304 			}
   2305 		} else if (sense->flags & SSD_FILEMARK) {
   2306 			retval = 0;
   2307 			if (st->fileno != (daddr_t) -1) {
   2308 				st->fileno++;
   2309 				st->blkno = 0;
   2310 				st->flags |= ST_POSUPDATED;
   2311 			}
   2312 		} else if (sense->flags & SSD_ILI) {
   2313 			if (info < 0) {
   2314 				/*
   2315 				 * The tape record was bigger than the read
   2316 				 * we issued.
   2317 				 */
   2318 				if ((xs->xs_control & XS_CTL_SILENT) == 0) {
   2319 					aprint_error_dev(st->sc_dev,
   2320 					    "%d-byte tape record too big"
   2321 					    " for %d-byte user buffer\n",
   2322 					    xs->datalen - info, xs->datalen);
   2323 				}
   2324 				retval = EIO;
   2325 			} else {
   2326 				retval = 0;
   2327 				if (st->blkno != (daddr_t) -1) {
   2328 					st->blkno++;
   2329 					st->flags |= ST_POSUPDATED;
   2330 				}
   2331 			}
   2332 		}
   2333 		if (bp)
   2334 			bp->b_resid = xs->resid;
   2335 	}
   2336 
   2337 #ifndef SCSIPI_DEBUG
   2338 	if (retval == 0 && key == SKEY_NO_SENSE)
   2339 		doprint = 0;
   2340 #endif
   2341 	if (key == SKEY_BLANK_CHECK) {
   2342 		/*
   2343 		 * This quirk code helps the drive read the
   2344 		 * first tape block, regardless of format.  That
   2345 		 * is required for these drives to return proper
   2346 		 * MODE SENSE information.
   2347 		 */
   2348 		if ((st->quirks & ST_Q_SENSE_HELP) &&
   2349 		    (periph->periph_flags & PERIPH_MEDIA_LOADED) == 0) {
   2350 			/* still starting */
   2351 			st->blksize -= 512;
   2352 		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
   2353 			st->flags |= ST_BLANK_READ;
   2354 			xs->resid = xs->datalen;
   2355 			if (bp) {
   2356 				bp->b_resid = xs->resid;
   2357 				/* return an EOF */
   2358 			}
   2359 			retval = 0;
   2360 			/* lost position */
   2361 			st->fileno = st->blkno = -1;
   2362 		}
   2363 	}
   2364 
   2365 	/*
   2366 	 * If generic sense processing will continue, we should not
   2367 	 * print sense info here.
   2368 	 */
   2369 	if (retval == EJUSTRETURN)
   2370 		doprint = 0;
   2371 
   2372 	if (doprint) {
   2373 		/* Print verbose sense info if possible */
   2374 		if (scsipi_print_sense(xs, 0) != 0)
   2375 			return retval;
   2376 
   2377 		/* Print less-verbose sense info */
   2378 		scsipi_printaddr(periph);
   2379 		printf("Sense Key 0x%02x", key);
   2380 		if ((sense->response_code & SSD_RCODE_VALID) != 0) {
   2381 			switch (key) {
   2382 			case SKEY_NOT_READY:
   2383 			case SKEY_ILLEGAL_REQUEST:
   2384 			case SKEY_UNIT_ATTENTION:
   2385 			case SKEY_DATA_PROTECT:
   2386 				break;
   2387 			case SKEY_VOLUME_OVERFLOW:
   2388 			case SKEY_BLANK_CHECK:
   2389 				printf(", requested size: %d (decimal)", info);
   2390 				break;
   2391 			case SKEY_ABORTED_COMMAND:
   2392 				if (xs->xs_retries)
   2393 					printf(", retrying");
   2394 				printf(", cmd 0x%x, info 0x%x",
   2395 				    xs->cmd->opcode, info);
   2396 				break;
   2397 			default:
   2398 				printf(", info = %d (decimal)", info);
   2399 			}
   2400 		}
   2401 		if (sense->extra_len != 0) {
   2402 			int n;
   2403 			printf(", data =");
   2404 			for (n = 0; n < sense->extra_len; n++)
   2405 				printf(" %02x", sense->csi[n]);
   2406 		}
   2407 		printf("\n");
   2408 	}
   2409 	return retval;
   2410 }
   2411 
   2412 /*
   2413  * The quirk here is that the drive returns some value to st_mode_sense
   2414  * incorrectly until the tape has actually passed by the head.
   2415  *
   2416  * The method is to set the drive to large fixed-block state (user-specified
   2417  * density and 1024-byte blocks), then read and rewind to get it to sense the
   2418  * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
   2419  * work, as a last resort, try variable- length blocks.  The result will be
   2420  * the ability to do an accurate st_mode_sense.
   2421  *
   2422  * We know we can do a rewind because we just did a load, which implies rewind.
   2423  * Rewind seems preferable to space backward if we have a virgin tape.
   2424  *
   2425  * The rest of the code for this quirk is in ILI processing and BLANK CHECK
   2426  * error processing, both part of st_interpret_sense.
   2427  */
   2428 static int
   2429 st_touch_tape(struct st_softc *st)
   2430 {
   2431 	char *bf;
   2432 	int readsize;
   2433 	int error;
   2434 
   2435 	bf = malloc(1024, M_TEMP, M_WAITOK);
   2436 	if ((error = st->ops(st, ST_OPS_MODESENSE, 0)) != 0)
   2437 		goto bad;
   2438 
   2439 	/*
   2440 	 * If the block size is already known from the
   2441 	 * sense data, use it. Else start probing at 1024.
   2442 	 */
   2443 	if (st->media_blksize > 0)
   2444 		st->blksize = st->media_blksize;
   2445 	else
   2446 		st->blksize = 1024;
   2447 
   2448 	do {
   2449 		switch (st->blksize) {
   2450 		case 512:
   2451 		case 1024:
   2452 			readsize = st->blksize;
   2453 			st->flags |= ST_FIXEDBLOCKS;
   2454 			break;
   2455 		default:
   2456 			readsize = 1;
   2457 			st->flags &= ~ST_FIXEDBLOCKS;
   2458 		}
   2459 		if ((error = st->ops(st, ST_OPS_MODESELECT, XS_CTL_SILENT))
   2460 		    != 0) {
   2461 			/*
   2462 			 * The device did not agree with the proposed
   2463 			 * block size. If we exhausted our options,
   2464 			 * return failure, else try another.
   2465 			 */
   2466 			if (readsize == 1)
   2467 				goto bad;
   2468 			st->blksize -= 512;
   2469 			continue;
   2470 		}
   2471 		st_read(st, bf, readsize, XS_CTL_SILENT);	/* XXX */
   2472 		if ((error = st_rewind(st, 0, 0)) != 0) {
   2473 bad:			free(bf, M_TEMP);
   2474 			return error;
   2475 		}
   2476 	} while (readsize != 1 && readsize > st->blksize);
   2477 
   2478 	free(bf, M_TEMP);
   2479 	return 0;
   2480 }
   2481 
   2482 static int
   2483 stdump(dev_t dev, daddr_t blkno, void *va, size_t size)
   2484 {
   2485 	/* Not implemented. */
   2486 	return ENXIO;
   2487 }
   2488 
   2489 /*
   2490  * Send a filled out parameter structure to the drive to
   2491  * set it into the desire modes etc.
   2492  */
   2493 int
   2494 st_mode_select(struct st_softc *st, int flags)
   2495 {
   2496 	u_int select_len;
   2497 	struct select {
   2498 		struct scsi_mode_parameter_header_6 header;
   2499 		struct scsi_general_block_descriptor blk_desc;
   2500 		u_char sense_data[MAX_PAGE_0_SIZE];
   2501 	} select;
   2502 	struct scsipi_periph *periph = st->sc_periph;
   2503 
   2504 	select_len = sizeof(select.header) + sizeof(select.blk_desc) +
   2505 		     st->page_0_size;
   2506 
   2507 	/*
   2508 	 * This quirk deals with drives that have only one valid mode
   2509 	 * and think this gives them license to reject all mode selects,
   2510 	 * even if the selected mode is the one that is supported.
   2511 	 */
   2512 	if (st->quirks & ST_Q_UNIMODAL) {
   2513 		SC_DEBUG(periph, SCSIPI_DB3,
   2514 		    ("not setting density 0x%x blksize 0x%x\n",
   2515 		    st->density, st->blksize));
   2516 		return 0;
   2517 	}
   2518 
   2519 	/* Set up for a mode select */
   2520 	memset(&select, 0, sizeof(select));
   2521 	select.header.blk_desc_len = sizeof(struct
   2522 	    scsi_general_block_descriptor);
   2523 	select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
   2524 	select.blk_desc.density = st->density;
   2525 	if (st->flags & ST_DONTBUFFER)
   2526 		select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
   2527 	else
   2528 		select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
   2529 	if (st->flags & ST_FIXEDBLOCKS)
   2530 		_lto3b(st->blksize, select.blk_desc.blklen);
   2531 	if (st->page_0_size)
   2532 		memcpy(select.sense_data, st->sense_data, st->page_0_size);
   2533 
   2534 	/* do the command */
   2535 	return scsipi_mode_select(periph, 0, &select.header, select_len,
   2536 				  flags, ST_RETRIES, ST_CTL_TIME);
   2537 }
   2538