initial commit
[freebsd-arm:freebsd-arm.git] / cam / scsi / scsi_sa.c
1 /*-
2  * Implementation of SCSI Sequential Access Peripheral driver for CAM.
3  *
4  * Copyright (c) 1999, 2000 Matthew Jacob
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions, and the following disclaimer,
12  *    without modification, immediately at the beginning of the file.
13  * 2. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/queue.h>
34 #ifdef _KERNEL
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #endif
38 #include <sys/types.h>
39 #include <sys/time.h>
40 #include <sys/bio.h>
41 #include <sys/limits.h>
42 #include <sys/malloc.h>
43 #include <sys/mtio.h>
44 #ifdef _KERNEL
45 #include <sys/conf.h>
46 #endif
47 #include <sys/fcntl.h>
48 #include <sys/devicestat.h>
49
50 #ifndef _KERNEL
51 #include <stdio.h>
52 #include <string.h>
53 #endif
54
55 #include <cam/cam.h>
56 #include <cam/cam_ccb.h>
57 #include <cam/cam_periph.h>
58 #include <cam/cam_xpt_periph.h>
59 #include <cam/cam_debug.h>
60
61 #include <cam/scsi/scsi_all.h>
62 #include <cam/scsi/scsi_message.h>
63 #include <cam/scsi/scsi_sa.h>
64
65 #ifdef _KERNEL
66
67 #include <opt_sa.h>
68
69 #ifndef SA_IO_TIMEOUT
70 #define SA_IO_TIMEOUT           4
71 #endif
72 #ifndef SA_SPACE_TIMEOUT
73 #define SA_SPACE_TIMEOUT        1 * 60
74 #endif
75 #ifndef SA_REWIND_TIMEOUT
76 #define SA_REWIND_TIMEOUT       2 * 60
77 #endif
78 #ifndef SA_ERASE_TIMEOUT
79 #define SA_ERASE_TIMEOUT        4 * 60
80 #endif
81
82 #define SCSIOP_TIMEOUT          (60 * 1000)     /* not an option */
83
84 #define IO_TIMEOUT              (SA_IO_TIMEOUT * 60 * 1000)
85 #define REWIND_TIMEOUT          (SA_REWIND_TIMEOUT * 60 * 1000)
86 #define ERASE_TIMEOUT           (SA_ERASE_TIMEOUT * 60 * 1000)
87 #define SPACE_TIMEOUT           (SA_SPACE_TIMEOUT * 60 * 1000)
88
89 /*
90  * Additional options that can be set for config: SA_1FM_AT_EOT
91  */
92
93 #ifndef UNUSED_PARAMETER
94 #define UNUSED_PARAMETER(x)     x = x
95 #endif
96
97 #define QFRLS(ccb)      \
98         if (((ccb)->ccb_h.status & CAM_DEV_QFRZN) != 0) \
99                 cam_release_devq((ccb)->ccb_h.path, 0, 0, 0, FALSE)
100
101 /*
102  * Driver states
103  */
104
105 MALLOC_DEFINE(M_SCSISA, "SCSI sa", "SCSI sequential access buffers");
106
107 typedef enum {
108         SA_STATE_NORMAL, SA_STATE_ABNORMAL
109 } sa_state;
110
111 #define ccb_pflags      ppriv_field0
112 #define ccb_bp          ppriv_ptr1
113
114 #define SA_CCB_BUFFER_IO        0x0
115 #define SA_CCB_WAITING          0x1
116 #define SA_CCB_TYPEMASK         0x1
117 #define SA_POSITION_UPDATED     0x2
118
119 #define Set_CCB_Type(x, type)                           \
120         x->ccb_h.ccb_pflags &= ~SA_CCB_TYPEMASK;        \
121         x->ccb_h.ccb_pflags |= type
122
123 #define CCB_Type(x)     (x->ccb_h.ccb_pflags & SA_CCB_TYPEMASK)
124
125
126
127 typedef enum {
128         SA_FLAG_OPEN            = 0x0001,
129         SA_FLAG_FIXED           = 0x0002,
130         SA_FLAG_TAPE_LOCKED     = 0x0004,
131         SA_FLAG_TAPE_MOUNTED    = 0x0008,
132         SA_FLAG_TAPE_WP         = 0x0010,
133         SA_FLAG_TAPE_WRITTEN    = 0x0020,
134         SA_FLAG_EOM_PENDING     = 0x0040,
135         SA_FLAG_EIO_PENDING     = 0x0080,
136         SA_FLAG_EOF_PENDING     = 0x0100,
137         SA_FLAG_ERR_PENDING     = (SA_FLAG_EOM_PENDING|SA_FLAG_EIO_PENDING|
138                                    SA_FLAG_EOF_PENDING),
139         SA_FLAG_INVALID         = 0x0200,
140         SA_FLAG_COMP_ENABLED    = 0x0400,
141         SA_FLAG_COMP_SUPP       = 0x0800,
142         SA_FLAG_COMP_UNSUPP     = 0x1000,
143         SA_FLAG_TAPE_FROZEN     = 0x2000
144 } sa_flags;
145
146 typedef enum {
147         SA_MODE_REWIND          = 0x00,
148         SA_MODE_NOREWIND        = 0x01,
149         SA_MODE_OFFLINE         = 0x02
150 } sa_mode;
151
152 typedef enum {
153         SA_PARAM_NONE           = 0x00,
154         SA_PARAM_BLOCKSIZE      = 0x01,
155         SA_PARAM_DENSITY        = 0x02,
156         SA_PARAM_COMPRESSION    = 0x04,
157         SA_PARAM_BUFF_MODE      = 0x08,
158         SA_PARAM_NUMBLOCKS      = 0x10,
159         SA_PARAM_WP             = 0x20,
160         SA_PARAM_SPEED          = 0x40,
161         SA_PARAM_ALL            = 0x7f
162 } sa_params;
163
164 typedef enum {
165         SA_QUIRK_NONE           = 0x00,
166         SA_QUIRK_NOCOMP         = 0x01, /* Can't deal with compression at all */
167         SA_QUIRK_FIXED          = 0x02, /* Force fixed mode */
168         SA_QUIRK_VARIABLE       = 0x04, /* Force variable mode */
169         SA_QUIRK_2FM            = 0x08, /* Needs Two File Marks at EOD */
170         SA_QUIRK_1FM            = 0x10, /* No more than 1 File Mark at EOD */
171         SA_QUIRK_NODREAD        = 0x20, /* Don't try and dummy read density */
172         SA_QUIRK_NO_MODESEL     = 0x40, /* Don't do mode select at all */
173         SA_QUIRK_NO_CPAGE       = 0x80  /* Don't use DEVICE COMPRESSION page */
174 } sa_quirks;
175
176 #define SAMODE(z)       (dev2unit(z) & 0x3)
177 #define SADENSITY(z)    ((dev2unit(z) >> 2) & 0x3)
178 #define SA_IS_CTRL(z)   (dev2unit(z) & (1 << 4))
179
180 #define SA_NOT_CTLDEV   0
181 #define SA_CTLDEV       1
182
183 #define SA_ATYPE_R      0
184 #define SA_ATYPE_NR     1
185 #define SA_ATYPE_ER     2
186
187 #define SAMINOR(ctl, mode, access) \
188         ((ctl << 4) | (mode << 2) | (access & 0x3))
189
190 #define SA_NUM_MODES    4
191 struct sa_devs {
192         struct cdev *ctl_dev;
193         struct sa_mode_devs {
194                 struct cdev *r_dev;
195                 struct cdev *nr_dev;
196                 struct cdev *er_dev;
197         } mode_devs[SA_NUM_MODES];
198 };
199
200 struct sa_softc {
201         sa_state        state;
202         sa_flags        flags;
203         sa_quirks       quirks;
204         struct          bio_queue_head bio_queue;
205         int             queue_count;
206         struct          devstat *device_stats;
207         struct sa_devs  devs;
208         int             blk_gran;
209         int             blk_mask;
210         int             blk_shift;
211         u_int32_t       max_blk;
212         u_int32_t       min_blk;
213         u_int32_t       comp_algorithm;
214         u_int32_t       saved_comp_algorithm;
215         u_int32_t       media_blksize;
216         u_int32_t       last_media_blksize;
217         u_int32_t       media_numblks;
218         u_int8_t        media_density;
219         u_int8_t        speed;
220         u_int8_t        scsi_rev;
221         u_int8_t        dsreg;          /* mtio mt_dsreg, redux */
222         int             buffer_mode;
223         int             filemarks;
224         union           ccb saved_ccb;
225         int             last_resid_was_io;
226
227         /*
228          * Relative to BOT Location.
229          */
230         daddr_t         fileno;
231         daddr_t         blkno;
232
233         /*
234          * Latched Error Info
235          */
236         struct {
237                 struct scsi_sense_data _last_io_sense;
238                 u_int32_t _last_io_resid;
239                 u_int8_t _last_io_cdb[CAM_MAX_CDBLEN];
240                 struct scsi_sense_data _last_ctl_sense;
241                 u_int32_t _last_ctl_resid;
242                 u_int8_t _last_ctl_cdb[CAM_MAX_CDBLEN];
243 #define last_io_sense   errinfo._last_io_sense
244 #define last_io_resid   errinfo._last_io_resid
245 #define last_io_cdb     errinfo._last_io_cdb
246 #define last_ctl_sense  errinfo._last_ctl_sense
247 #define last_ctl_resid  errinfo._last_ctl_resid
248 #define last_ctl_cdb    errinfo._last_ctl_cdb
249         } errinfo;
250         /*
251          * Misc other flags/state
252          */
253         u_int32_t
254                                         : 29,
255                 open_rdonly             : 1,    /* open read-only */
256                 open_pending_mount      : 1,    /* open pending mount */
257                 ctrl_mode               : 1;    /* control device open */
258 };
259
260 struct sa_quirk_entry {
261         struct scsi_inquiry_pattern inq_pat;    /* matching pattern */
262         sa_quirks quirks;       /* specific quirk type */
263         u_int32_t prefblk;      /* preferred blocksize when in fixed mode */
264 };
265
266 static struct sa_quirk_entry sa_quirk_table[] =
267 {
268         {
269                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "OnStream",
270                   "ADR*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_NODREAD |
271                    SA_QUIRK_1FM|SA_QUIRK_NO_MODESEL, 32768
272         },
273         {
274                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
275                   "Python 06408*", "*"}, SA_QUIRK_NODREAD, 0
276         },
277         {
278                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
279                   "Python 25601*", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_NODREAD, 0
280         },
281         {
282                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
283                   "Python*", "*"}, SA_QUIRK_NODREAD, 0
284         },
285         {
286                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
287                   "VIPER 150*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
288         },
289         {
290                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
291                   "VIPER 2525 25462", "-011"},
292                   SA_QUIRK_NOCOMP|SA_QUIRK_1FM|SA_QUIRK_NODREAD, 0
293         },
294         {
295                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
296                   "VIPER 2525*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 1024
297         },
298 #if     0
299         {
300                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
301                   "C15*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_NO_CPAGE, 0,
302         },
303 #endif
304         {
305                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
306                   "C56*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
307         },
308         {
309                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
310                   "T20*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
311         },
312         {
313                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
314                   "T4000*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
315         },
316         {
317                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
318                   "HP-88780*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
319         },
320         {
321                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "KENNEDY",
322                   "*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
323         },
324         {
325                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "M4 DATA",
326                   "123107 SCSI*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
327         },
328         {       /* jreynold@primenet.com */
329                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "Seagate",
330                 "STT8000N*", "*"}, SA_QUIRK_1FM, 0
331         },
332         {       /* mike@sentex.net */
333                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "Seagate",
334                 "STT20000*", "*"}, SA_QUIRK_1FM, 0
335         },
336         {
337                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
338                   " TDC 3600", "U07:"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
339         },
340         {
341                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
342                   " TDC 3800", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
343         },
344         {
345                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
346                   " TDC 4100", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
347         },
348         {
349                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
350                   " TDC 4200", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
351         },
352         {
353                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
354                   " SLR*", "*"}, SA_QUIRK_1FM, 0
355         },
356         {
357                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "WANGTEK",
358                   "5525ES*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
359         },
360         {
361                 { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "WANGTEK",
362                   "51000*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 1024
363         }
364 };
365
366 static  d_open_t        saopen;
367 static  d_close_t       saclose;
368 static  d_strategy_t    sastrategy;
369 static  d_ioctl_t       saioctl;
370 static  periph_init_t   sainit;
371 static  periph_ctor_t   saregister;
372 static  periph_oninv_t  saoninvalidate;
373 static  periph_dtor_t   sacleanup;
374 static  periph_start_t  sastart;
375 static  void            saasync(void *callback_arg, u_int32_t code,
376                                 struct cam_path *path, void *arg);
377 static  void            sadone(struct cam_periph *periph,
378                                union ccb *start_ccb);
379 static  int             saerror(union ccb *ccb, u_int32_t cam_flags,
380                                 u_int32_t sense_flags);
381 static int              samarkswanted(struct cam_periph *);
382 static int              sacheckeod(struct cam_periph *periph);
383 static int              sagetparams(struct cam_periph *periph,
384                                     sa_params params_to_get,
385                                     u_int32_t *blocksize, u_int8_t *density,
386                                     u_int32_t *numblocks, int *buff_mode,
387                                     u_int8_t *write_protect, u_int8_t *speed,
388                                     int *comp_supported, int *comp_enabled,
389                                     u_int32_t *comp_algorithm,
390                                     sa_comp_t *comp_page);
391 static int              sasetparams(struct cam_periph *periph,
392                                     sa_params params_to_set,
393                                     u_int32_t blocksize, u_int8_t density,
394                                     u_int32_t comp_algorithm,
395                                     u_int32_t sense_flags);
396 static void             saprevent(struct cam_periph *periph, int action);
397 static int              sarewind(struct cam_periph *periph);
398 static int              saspace(struct cam_periph *periph, int count,
399                                 scsi_space_code code);
400 static int              samount(struct cam_periph *, int, struct cdev *);
401 static int              saretension(struct cam_periph *periph);
402 static int              sareservereleaseunit(struct cam_periph *periph,
403                                              int reserve);
404 static int              saloadunload(struct cam_periph *periph, int load);
405 static int              saerase(struct cam_periph *periph, int longerase);
406 static int              sawritefilemarks(struct cam_periph *periph,
407                                          int nmarks, int setmarks);
408 static int              sardpos(struct cam_periph *periph, int, u_int32_t *);
409 static int              sasetpos(struct cam_periph *periph, int, u_int32_t *);
410
411
412 static struct periph_driver sadriver =
413 {
414         sainit, "sa",
415         TAILQ_HEAD_INITIALIZER(sadriver.units), /* generation */ 0
416 };
417
418 PERIPHDRIVER_DECLARE(sa, sadriver);
419
420 /* For 2.2-stable support */
421 #ifndef D_TAPE
422 #define D_TAPE 0
423 #endif
424
425
426 static struct cdevsw sa_cdevsw = {
427         .d_version =    D_VERSION,
428         .d_open =       saopen,
429         .d_close =      saclose,
430         .d_read =       physread,
431         .d_write =      physwrite,
432         .d_ioctl =      saioctl,
433         .d_strategy =   sastrategy,
434         .d_name =       "sa",
435         .d_flags =      D_TAPE | D_NEEDGIANT,
436 };
437
438 static int
439 saopen(struct cdev *dev, int flags, int fmt, struct thread *td)
440 {
441         struct cam_periph *periph;
442         struct sa_softc *softc;
443         int error;
444
445         periph = (struct cam_periph *)dev->si_drv1;
446         if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
447                 return (ENXIO);
448         }
449
450         cam_periph_lock(periph);
451
452         softc = (struct sa_softc *)periph->softc;
453
454         CAM_DEBUG(periph->path, CAM_DEBUG_TRACE|CAM_DEBUG_INFO,
455             ("saopen(%s): softc=0x%x\n", devtoname(dev), softc->flags));
456
457         if (SA_IS_CTRL(dev)) {
458                 softc->ctrl_mode = 1;
459                 cam_periph_unlock(periph);
460                 return (0);
461         }
462
463         if ((error = cam_periph_hold(periph, PRIBIO|PCATCH)) != 0) {
464                 cam_periph_unlock(periph);
465                 cam_periph_release(periph);
466                 return (error);
467         }
468
469         if (softc->flags & SA_FLAG_OPEN) {
470                 error = EBUSY;
471         } else if (softc->flags & SA_FLAG_INVALID) {
472                 error = ENXIO;
473         } else {
474                 /*
475                  * Preserve whether this is a read_only open.
476                  */
477                 softc->open_rdonly = (flags & O_RDWR) == O_RDONLY;
478
479                 /*
480                  * The function samount ensures media is loaded and ready.
481                  * It also does a device RESERVE if the tape isn't yet mounted.
482                  *
483                  * If the mount fails and this was a non-blocking open,
484                  * make this a 'open_pending_mount' action.
485                  */
486                 error = samount(periph, flags, dev);
487                 if (error && (flags & O_NONBLOCK)) {
488                         softc->flags |= SA_FLAG_OPEN;
489                         softc->open_pending_mount = 1;
490                         cam_periph_unhold(periph);
491                         cam_periph_unlock(periph);
492                         return (0);
493                 }
494         }
495
496         if (error) {
497                 cam_periph_unhold(periph);
498                 cam_periph_unlock(periph);
499                 cam_periph_release(periph);
500                 return (error);
501         }
502
503         saprevent(periph, PR_PREVENT);
504         softc->flags |= SA_FLAG_OPEN;
505
506         cam_periph_unhold(periph);
507         cam_periph_unlock(periph);
508         return (error);
509 }
510
511 static int
512 saclose(struct cdev *dev, int flag, int fmt, struct thread *td)
513 {
514         struct  cam_periph *periph;
515         struct  sa_softc *softc;
516         int     mode, error, writing, tmp;
517         int     closedbits = SA_FLAG_OPEN;
518
519         mode = SAMODE(dev);
520         periph = (struct cam_periph *)dev->si_drv1;
521         if (periph == NULL)
522                 return (ENXIO); 
523
524         cam_periph_lock(periph);
525
526         softc = (struct sa_softc *)periph->softc;
527
528         CAM_DEBUG(periph->path, CAM_DEBUG_TRACE|CAM_DEBUG_INFO,
529             ("saclose(%s): softc=0x%x\n", devtoname(dev), softc->flags));
530
531
532         softc->open_rdonly = 0; 
533         if (SA_IS_CTRL(dev)) {
534                 softc->ctrl_mode = 0;
535                 cam_periph_unlock(periph);
536                 cam_periph_release(periph);
537                 return (0);
538         }
539
540         if (softc->open_pending_mount) {
541                 softc->flags &= ~SA_FLAG_OPEN;
542                 softc->open_pending_mount = 0; 
543                 cam_periph_unlock(periph);
544                 cam_periph_release(periph);
545                 return (0);
546         }
547
548         if ((error = cam_periph_hold(periph, PRIBIO)) != 0) {
549                 cam_periph_unlock(periph);
550                 return (error);
551         }
552
553         /*
554          * Were we writing the tape?
555          */
556         writing = (softc->flags & SA_FLAG_TAPE_WRITTEN) != 0;
557
558         /*
559          * See whether or not we need to write filemarks. If this
560          * fails, we probably have to assume we've lost tape
561          * position.
562          */
563         error = sacheckeod(periph);
564         if (error) {
565                 xpt_print(periph->path,
566                     "failed to write terminating filemark(s)\n");
567                 softc->flags |= SA_FLAG_TAPE_FROZEN;
568         }
569
570         /*
571          * Whatever we end up doing, allow users to eject tapes from here on.
572          */
573         saprevent(periph, PR_ALLOW);
574
575         /*
576          * Decide how to end...
577          */
578         if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0) {
579                 closedbits |= SA_FLAG_TAPE_FROZEN;
580         } else switch (mode) {
581         case SA_MODE_OFFLINE:
582                 /*
583                  * An 'offline' close is an unconditional release of
584                  * frozen && mount conditions, irrespective of whether
585                  * these operations succeeded. The reason for this is
586                  * to allow at least some kind of programmatic way
587                  * around our state getting all fouled up. If somebody
588                  * issues an 'offline' command, that will be allowed
589                  * to clear state.
590                  */
591                 (void) sarewind(periph);
592                 (void) saloadunload(periph, FALSE);
593                 closedbits |= SA_FLAG_TAPE_MOUNTED|SA_FLAG_TAPE_FROZEN;
594                 break;
595         case SA_MODE_REWIND:
596                 /*
597                  * If the rewind fails, return an error- if anyone cares,
598                  * but not overwriting any previous error.
599                  *
600                  * We don't clear the notion of mounted here, but we do
601                  * clear the notion of frozen if we successfully rewound.
602                  */
603                 tmp = sarewind(periph);
604                 if (tmp) {
605                         if (error != 0)
606                                 error = tmp;
607                 } else {
608                         closedbits |= SA_FLAG_TAPE_FROZEN;
609                 }
610                 break;
611         case SA_MODE_NOREWIND:
612                 /*
613                  * If we're not rewinding/unloading the tape, find out
614                  * whether we need to back up over one of two filemarks
615                  * we wrote (if we wrote two filemarks) so that appends
616                  * from this point on will be sane.
617                  */
618                 if (error == 0 && writing && (softc->quirks & SA_QUIRK_2FM)) {
619                         tmp = saspace(periph, -1, SS_FILEMARKS);
620                         if (tmp) {
621                                 xpt_print(periph->path, "unable to backspace "
622                                     "over one of double filemarks at end of "
623                                     "tape\n");
624                                 xpt_print(periph->path, "it is possible that "
625                                     "this device needs a SA_QUIRK_1FM quirk set"
626                                     "for it\n");
627                                 softc->flags |= SA_FLAG_TAPE_FROZEN;
628                         }
629                 }
630                 break;
631         default:
632                 xpt_print(periph->path, "unknown mode 0x%x in saclose\n", mode);
633                 /* NOTREACHED */
634                 break;
635         }
636
637         /*
638          * We wish to note here that there are no more filemarks to be written.
639          */
640         softc->filemarks = 0;
641         softc->flags &= ~SA_FLAG_TAPE_WRITTEN;
642
643         /*
644          * And we are no longer open for business.
645          */
646         softc->flags &= ~closedbits;
647
648         /*
649          * Inform users if tape state if frozen....
650          */
651         if (softc->flags & SA_FLAG_TAPE_FROZEN) {
652                 xpt_print(periph->path, "tape is now frozen- use an OFFLINE, "
653                     "REWIND or MTEOM command to clear this state.\n");
654         }
655         
656         /* release the device if it is no longer mounted */
657         if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0)
658                 sareservereleaseunit(periph, FALSE);
659
660         cam_periph_unhold(periph);
661         cam_periph_unlock(periph);
662         cam_periph_release(periph);
663
664         return (error); 
665 }
666
667 /*
668  * Actually translate the requested transfer into one the physical driver
669  * can understand.  The transfer is described by a buf and will include
670  * only one physical transfer.
671  */
672 static void
673 sastrategy(struct bio *bp)
674 {
675         struct cam_periph *periph;
676         struct sa_softc *softc;
677         
678         bp->bio_resid = bp->bio_bcount;
679         if (SA_IS_CTRL(bp->bio_dev)) {
680                 biofinish(bp, NULL, EINVAL);
681                 return;
682         }
683         periph = (struct cam_periph *)bp->bio_dev->si_drv1;
684         if (periph == NULL) {
685                 biofinish(bp, NULL, ENXIO);
686                 return;
687         }
688         cam_periph_lock(periph);
689
690         softc = (struct sa_softc *)periph->softc;
691
692         if (softc->flags & SA_FLAG_INVALID) {
693                 cam_periph_unlock(periph);
694                 biofinish(bp, NULL, ENXIO);
695                 return;
696         }
697
698         if (softc->flags & SA_FLAG_TAPE_FROZEN) {
699                 cam_periph_unlock(periph);
700                 biofinish(bp, NULL, EPERM);
701                 return;
702         }
703
704         /*
705          * This should actually never occur as the write(2)
706          * system call traps attempts to write to a read-only
707          * file descriptor.
708          */
709         if (bp->bio_cmd == BIO_WRITE && softc->open_rdonly) {
710                 cam_periph_unlock(periph);
711                 biofinish(bp, NULL, EBADF);
712                 return;
713         }
714
715         if (softc->open_pending_mount) {
716                 int error = samount(periph, 0, bp->bio_dev);
717                 if (error) {
718                         cam_periph_unlock(periph);
719                         biofinish(bp, NULL, ENXIO);
720                         return;
721                 }
722                 saprevent(periph, PR_PREVENT);
723                 softc->open_pending_mount = 0;
724         }
725
726
727         /*
728          * If it's a null transfer, return immediately
729          */
730         if (bp->bio_bcount == 0) {
731                 cam_periph_unlock(periph);
732                 biodone(bp);
733                 return;
734         }
735
736         /* valid request?  */
737         if (softc->flags & SA_FLAG_FIXED) {
738                 /*
739                  * Fixed block device.  The byte count must
740                  * be a multiple of our block size.
741                  */
742                 if (((softc->blk_mask != ~0) &&
743                     ((bp->bio_bcount & softc->blk_mask) != 0)) ||
744                     ((softc->blk_mask == ~0) &&
745                     ((bp->bio_bcount % softc->min_blk) != 0))) {
746                         xpt_print(periph->path, "Invalid request.  Fixed block "
747                             "device requests must be a multiple of %d bytes\n",
748                             softc->min_blk);
749                         cam_periph_unlock(periph);
750                         biofinish(bp, NULL, EINVAL);
751                         return;
752                 }
753         } else if ((bp->bio_bcount > softc->max_blk) ||
754                    (bp->bio_bcount < softc->min_blk) ||
755                    (bp->bio_bcount & softc->blk_mask) != 0) {
756
757                 xpt_print_path(periph->path);
758                 printf("Invalid request.  Variable block "
759                     "device requests must be ");
760                 if (softc->blk_mask != 0) {
761                         printf("a multiple of %d ", (0x1 << softc->blk_gran));
762                 }
763                 printf("between %d and %d bytes\n", softc->min_blk,
764                     softc->max_blk);
765                 cam_periph_unlock(periph);
766                 biofinish(bp, NULL, EINVAL);
767                 return;
768         }
769         
770         /*
771          * Place it at the end of the queue.
772          */
773         bioq_insert_tail(&softc->bio_queue, bp);
774         softc->queue_count++;
775 #if     0
776         CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
777             ("sastrategy: queuing a %ld %s byte %s\n", bp->bio_bcount,
778             (softc->flags & SA_FLAG_FIXED)?  "fixed" : "variable",
779             (bp->bio_cmd == BIO_READ)? "read" : "write"));
780 #endif
781         if (softc->queue_count > 1) {
782                 CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
783                     ("sastrategy: queue count now %d\n", softc->queue_count));
784         }
785         
786         /*
787          * Schedule ourselves for performing the work.
788          */
789         xpt_schedule(periph, CAM_PRIORITY_NORMAL);
790         cam_periph_unlock(periph);
791
792         return;
793 }
794
795
796 #define PENDING_MOUNT_CHECK(softc, periph, dev)         \
797         if (softc->open_pending_mount) {                \
798                 error = samount(periph, 0, dev);        \
799                 if (error) {                            \
800                         break;                          \
801                 }                                       \
802                 saprevent(periph, PR_PREVENT);          \
803                 softc->open_pending_mount = 0;          \
804         }
805
806 static int
807 saioctl(struct cdev *dev, u_long cmd, caddr_t arg, int flag, struct thread *td)
808 {
809         struct cam_periph *periph;
810         struct sa_softc *softc;
811         scsi_space_code spaceop;
812         int didlockperiph = 0;
813         int mode;
814         int error = 0;
815
816         mode = SAMODE(dev);
817         error = 0;              /* shut up gcc */
818         spaceop = 0;            /* shut up gcc */
819
820         periph = (struct cam_periph *)dev->si_drv1;
821         if (periph == NULL)
822                 return (ENXIO); 
823
824         cam_periph_lock(periph);
825         softc = (struct sa_softc *)periph->softc;
826
827         /*
828          * Check for control mode accesses. We allow MTIOCGET and
829          * MTIOCERRSTAT (but need to be the only one open in order
830          * to clear latched status), and MTSETBSIZE, MTSETDNSTY
831          * and MTCOMP (but need to be the only one accessing this
832          * device to run those).
833          */
834
835         if (SA_IS_CTRL(dev)) {
836                 switch (cmd) {
837                 case MTIOCGETEOTMODEL:
838                 case MTIOCGET:
839                         break;
840                 case MTIOCERRSTAT:
841                         /*
842                          * If the periph isn't already locked, lock it
843                          * so our MTIOCERRSTAT can reset latched error stats.
844                          *
845                          * If the periph is already locked, skip it because
846                          * we're just getting status and it'll be up to the
847                          * other thread that has this device open to do
848                          * an MTIOCERRSTAT that would clear latched status.
849                          */
850                         if ((periph->flags & CAM_PERIPH_LOCKED) == 0) {
851                                 error = cam_periph_hold(periph, PRIBIO|PCATCH);
852                                  if (error != 0)
853                                         return (error);
854                                 didlockperiph = 1;
855                         }
856                         break;
857
858                 case MTIOCTOP:
859                 {
860                         struct mtop *mt = (struct mtop *) arg;
861
862                         /*
863                          * Check to make sure it's an OP we can perform
864                          * with no media inserted.
865                          */
866                         switch (mt->mt_op) {
867                         case MTSETBSIZ:
868                         case MTSETDNSTY:
869                         case MTCOMP:
870                                 mt = NULL;
871                                 /* FALLTHROUGH */
872                         default:
873                                 break;
874                         }
875                         if (mt != NULL) {
876                                 break;
877                         }
878                         /* FALLTHROUGH */
879                 }
880                 case MTIOCSETEOTMODEL:
881                         /*
882                          * We need to acquire the peripheral here rather
883                          * than at open time because we are sharing writable
884                          * access to data structures.
885                          */
886                         error = cam_periph_hold(periph, PRIBIO|PCATCH);
887                         if (error != 0)
888                                 return (error);
889                         didlockperiph = 1;
890                         break;
891
892                 default:
893                         return (EINVAL);
894                 }
895         }
896
897         /*
898          * Find the device that the user is talking about
899          */
900         switch (cmd) {
901         case MTIOCGET:
902         {
903                 struct mtget *g = (struct mtget *)arg;
904
905                 /*
906                  * If this isn't the control mode device, actually go out
907                  * and ask the drive again what it's set to.
908                  */
909                 if (!SA_IS_CTRL(dev) && !softc->open_pending_mount) {
910                         u_int8_t write_protect;
911                         int comp_enabled, comp_supported;
912                         error = sagetparams(periph, SA_PARAM_ALL,
913                             &softc->media_blksize, &softc->media_density,
914                             &softc->media_numblks, &softc->buffer_mode,
915                             &write_protect, &softc->speed, &comp_supported,
916                             &comp_enabled, &softc->comp_algorithm, NULL);
917                         if (error)
918                                 break;
919                         if (write_protect)
920                                 softc->flags |= SA_FLAG_TAPE_WP;
921                         else
922                                 softc->flags &= ~SA_FLAG_TAPE_WP;
923                         softc->flags &= ~(SA_FLAG_COMP_SUPP|
924                             SA_FLAG_COMP_ENABLED|SA_FLAG_COMP_UNSUPP);
925                         if (comp_supported) {
926                                 if (softc->saved_comp_algorithm == 0)
927                                         softc->saved_comp_algorithm =
928                                             softc->comp_algorithm;
929                                 softc->flags |= SA_FLAG_COMP_SUPP;
930                                 if (comp_enabled)
931                                         softc->flags |= SA_FLAG_COMP_ENABLED;
932                         } else  
933                                 softc->flags |= SA_FLAG_COMP_UNSUPP;
934                 }
935                 bzero(g, sizeof(struct mtget));
936                 g->mt_type = MT_ISAR;
937                 if (softc->flags & SA_FLAG_COMP_UNSUPP) {
938                         g->mt_comp = MT_COMP_UNSUPP;
939                         g->mt_comp0 = MT_COMP_UNSUPP;
940                         g->mt_comp1 = MT_COMP_UNSUPP;
941                         g->mt_comp2 = MT_COMP_UNSUPP;
942                         g->mt_comp3 = MT_COMP_UNSUPP;
943                 } else {
944                         if ((softc->flags & SA_FLAG_COMP_ENABLED) == 0) {
945                                 g->mt_comp = MT_COMP_DISABLED;
946                         } else {
947                                 g->mt_comp = softc->comp_algorithm;
948                         }
949                         g->mt_comp0 = softc->comp_algorithm;
950                         g->mt_comp1 = softc->comp_algorithm;
951                         g->mt_comp2 = softc->comp_algorithm;
952                         g->mt_comp3 = softc->comp_algorithm;
953                 }
954                 g->mt_density = softc->media_density;
955                 g->mt_density0 = softc->media_density;
956                 g->mt_density1 = softc->media_density;
957                 g->mt_density2 = softc->media_density;
958                 g->mt_density3 = softc->media_density;
959                 g->mt_blksiz = softc->media_blksize;
960                 g->mt_blksiz0 = softc->media_blksize;
961                 g->mt_blksiz1 = softc->media_blksize;
962                 g->mt_blksiz2 = softc->media_blksize;
963                 g->mt_blksiz3 = softc->media_blksize;
964                 g->mt_fileno = softc->fileno;
965                 g->mt_blkno = softc->blkno;
966                 g->mt_dsreg = (short) softc->dsreg;
967                 /*
968                  * Yes, we know that this is likely to overflow
969                  */
970                 if (softc->last_resid_was_io) {
971                         if ((g->mt_resid = (short) softc->last_io_resid) != 0) {
972                                 if (SA_IS_CTRL(dev) == 0 || didlockperiph) {
973                                         softc->last_io_resid = 0;
974                                 }
975                         }
976                 } else {
977                         if ((g->mt_resid = (short)softc->last_ctl_resid) != 0) {
978                                 if (SA_IS_CTRL(dev) == 0 || didlockperiph) {
979                                         softc->last_ctl_resid = 0;
980                                 }
981                         }
982                 }
983                 error = 0;
984                 break;
985         }
986         case MTIOCERRSTAT:
987         {
988                 struct scsi_tape_errors *sep =
989                     &((union mterrstat *)arg)->scsi_errstat;
990
991                 CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
992                     ("saioctl: MTIOCERRSTAT\n"));
993
994                 bzero(sep, sizeof(*sep));
995                 sep->io_resid = softc->last_io_resid;
996                 bcopy((caddr_t) &softc->last_io_sense, sep->io_sense,
997                     sizeof (sep->io_sense));
998                 bcopy((caddr_t) &softc->last_io_cdb, sep->io_cdb,
999                     sizeof (sep->io_cdb));
1000                 sep->ctl_resid = softc->last_ctl_resid;
1001                 bcopy((caddr_t) &softc->last_ctl_sense, sep->ctl_sense,
1002                     sizeof (sep->ctl_sense));
1003                 bcopy((caddr_t) &softc->last_ctl_cdb, sep->ctl_cdb,
1004                     sizeof (sep->ctl_cdb));
1005
1006                 if ((SA_IS_CTRL(dev) == 0 && softc->open_pending_mount) ||
1007                     didlockperiph)
1008                         bzero((caddr_t) &softc->errinfo,
1009                             sizeof (softc->errinfo));
1010                 error = 0;
1011                 break;
1012         }
1013         case MTIOCTOP:
1014         {
1015                 struct mtop *mt;
1016                 int    count;
1017
1018                 PENDING_MOUNT_CHECK(softc, periph, dev);
1019
1020                 mt = (struct mtop *)arg;
1021
1022
1023                 CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
1024                          ("saioctl: op=0x%x count=0x%x\n",
1025                           mt->mt_op, mt->mt_count));
1026
1027                 count = mt->mt_count;
1028                 switch (mt->mt_op) {
1029                 case MTWEOF:    /* write an end-of-file marker */
1030                         /*
1031                          * We don't need to clear the SA_FLAG_TAPE_WRITTEN
1032                          * flag because by keeping track of filemarks
1033                          * we have last written we know ehether or not
1034                          * we need to write more when we close the device.
1035                          */
1036                         error = sawritefilemarks(periph, count, FALSE);
1037                         break;
1038                 case MTWSS:     /* write a setmark */
1039                         error = sawritefilemarks(periph, count, TRUE);
1040                         break;
1041                 case MTBSR:     /* backward space record */
1042                 case MTFSR:     /* forward space record */
1043                 case MTBSF:     /* backward space file */
1044                 case MTFSF:     /* forward space file */
1045                 case MTBSS:     /* backward space setmark */
1046                 case MTFSS:     /* forward space setmark */
1047                 case MTEOD:     /* space to end of recorded medium */
1048                 {
1049                         int nmarks;
1050
1051                         spaceop = SS_FILEMARKS;
1052                         nmarks = softc->filemarks;
1053                         error = sacheckeod(periph);
1054                         if (error) {
1055                                 xpt_print(periph->path,
1056                                     "EOD check prior to spacing failed\n");
1057                                 softc->flags |= SA_FLAG_EIO_PENDING;
1058                                 break;
1059                         }
1060                         nmarks -= softc->filemarks;
1061                         switch(mt->mt_op) {
1062                         case MTBSR:
1063                                 count = -count;
1064                                 /* FALLTHROUGH */
1065                         case MTFSR:
1066                                 spaceop = SS_BLOCKS;
1067                                 break;
1068                         case MTBSF:
1069                                 count = -count;
1070                                 /* FALLTHROUGH */
1071                         case MTFSF:
1072                                 break;
1073                         case MTBSS:
1074                                 count = -count;
1075                                 /* FALLTHROUGH */
1076                         case MTFSS:
1077                                 spaceop = SS_SETMARKS;
1078                                 break;
1079                         case MTEOD:
1080                                 spaceop = SS_EOD;
1081                                 count = 0;
1082                                 nmarks = 0;
1083                                 break;
1084                         default:
1085                                 error = EINVAL;
1086                                 break;
1087                         }
1088                         if (error)
1089                                 break;
1090
1091                         nmarks = softc->filemarks;
1092                         /*
1093                          * XXX: Why are we checking again?
1094                          */
1095                         error = sacheckeod(periph);
1096                         if (error)
1097                                 break;
1098                         nmarks -= softc->filemarks;
1099                         error = saspace(periph, count - nmarks, spaceop);
1100                         /*
1101                          * At this point, clear that we've written the tape
1102                          * and that we've written any filemarks. We really
1103                          * don't know what the applications wishes to do next-
1104                          * the sacheckeod's will make sure we terminated the
1105                          * tape correctly if we'd been writing, but the next
1106                          * action the user application takes will set again
1107                          * whether we need to write filemarks.
1108                          */
1109                         softc->flags &=
1110                             ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
1111                         softc->filemarks = 0;
1112                         break;
1113                 }
1114                 case MTREW:     /* rewind */
1115                         PENDING_MOUNT_CHECK(softc, periph, dev);
1116                         (void) sacheckeod(periph);
1117                         error = sarewind(periph);
1118                         /* see above */
1119                         softc->flags &=
1120                             ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
1121                         softc->flags &= ~SA_FLAG_ERR_PENDING;
1122                         softc->filemarks = 0;
1123                         break;
1124                 case MTERASE:   /* erase */
1125                         PENDING_MOUNT_CHECK(softc, periph, dev);
1126                         error = saerase(periph, count);
1127                         softc->flags &=
1128                             ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
1129                         softc->flags &= ~SA_FLAG_ERR_PENDING;
1130                         break;
1131                 case MTRETENS:  /* re-tension tape */
1132                         PENDING_MOUNT_CHECK(softc, periph, dev);
1133                         error = saretension(periph);            
1134                         softc->flags &=
1135                             ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
1136                         softc->flags &= ~SA_FLAG_ERR_PENDING;
1137                         break;
1138                 case MTOFFL:    /* rewind and put the drive offline */
1139
1140                         PENDING_MOUNT_CHECK(softc, periph, dev);
1141
1142                         (void) sacheckeod(periph);
1143                         /* see above */
1144                         softc->flags &= ~SA_FLAG_TAPE_WRITTEN;
1145                         softc->filemarks = 0;
1146
1147                         error = sarewind(periph);
1148                         /* clear the frozen flag anyway */
1149                         softc->flags &= ~SA_FLAG_TAPE_FROZEN;
1150
1151                         /*
1152                          * Be sure to allow media removal before ejecting.
1153                          */
1154
1155                         saprevent(periph, PR_ALLOW);
1156                         if (error == 0) {
1157                                 error = saloadunload(periph, FALSE);
1158                                 if (error == 0) {
1159                                         softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
1160                                 }
1161                         }
1162                         break;
1163
1164                 case MTNOP:     /* no operation, sets status only */
1165                 case MTCACHE:   /* enable controller cache */
1166                 case MTNOCACHE: /* disable controller cache */
1167                         error = 0;
1168                         break;
1169
1170                 case MTSETBSIZ: /* Set block size for device */
1171
1172                         PENDING_MOUNT_CHECK(softc, periph, dev);
1173
1174                         error = sasetparams(periph, SA_PARAM_BLOCKSIZE, count,
1175                                             0, 0, 0);
1176                         if (error == 0) {
1177                                 softc->last_media_blksize =
1178                                     softc->media_blksize;
1179                                 softc->media_blksize = count;
1180                                 if (count) {
1181                                         softc->flags |= SA_FLAG_FIXED;
1182                                         if (powerof2(count)) {
1183                                                 softc->blk_shift =
1184                                                     ffs(count) - 1;
1185                                                 softc->blk_mask = count - 1;
1186                                         } else {
1187                                                 softc->blk_mask = ~0;
1188                                                 softc->blk_shift = 0;
1189                                         }
1190                                         /*
1191                                          * Make the user's desire 'persistent'.
1192                                          */
1193                                         softc->quirks &= ~SA_QUIRK_VARIABLE;
1194                                         softc->quirks |= SA_QUIRK_FIXED;
1195                                 } else {
1196                                         softc->flags &= ~SA_FLAG_FIXED;
1197                                         if (softc->max_blk == 0) {
1198                                                 softc->max_blk = ~0;
1199                                         }
1200                                         softc->blk_shift = 0;
1201                                         if (softc->blk_gran != 0) {
1202                                                 softc->blk_mask =
1203                                                     softc->blk_gran - 1;
1204                                         } else {
1205                                                 softc->blk_mask = 0;
1206                                         }
1207                                         /*
1208                                          * Make the user's desire 'persistent'.
1209                                          */
1210                                         softc->quirks |= SA_QUIRK_VARIABLE;
1211                                         softc->quirks &= ~SA_QUIRK_FIXED;
1212                                 }
1213                         }
1214                         break;
1215                 case MTSETDNSTY:        /* Set density for device and mode */
1216                         PENDING_MOUNT_CHECK(softc, periph, dev);
1217
1218                         if (count > UCHAR_MAX) {
1219                                 error = EINVAL; 
1220                                 break;
1221                         } else {
1222                                 error = sasetparams(periph, SA_PARAM_DENSITY,
1223                                                     0, count, 0, 0);
1224                         }
1225                         break;
1226                 case MTCOMP:    /* enable compression */
1227                         PENDING_MOUNT_CHECK(softc, periph, dev);
1228                         /*
1229                          * Some devices don't support compression, and
1230                          * don't like it if you ask them for the
1231                          * compression page.
1232                          */
1233                         if ((softc->quirks & SA_QUIRK_NOCOMP) ||
1234                             (softc->flags & SA_FLAG_COMP_UNSUPP)) {
1235                                 error = ENODEV;
1236                                 break;
1237                         }
1238                         error = sasetparams(periph, SA_PARAM_COMPRESSION,
1239                             0, 0, count, SF_NO_PRINT);
1240                         break;
1241                 default:
1242                         error = EINVAL;
1243                 }
1244                 break;
1245         }
1246         case MTIOCIEOT:
1247         case MTIOCEEOT:
1248                 error = 0;
1249                 break;
1250         case MTIOCRDSPOS:
1251                 PENDING_MOUNT_CHECK(softc, periph, dev);
1252                 error = sardpos(periph, 0, (u_int32_t *) arg);
1253                 break;
1254         case MTIOCRDHPOS:
1255                 PENDING_MOUNT_CHECK(softc, periph, dev);
1256                 error = sardpos(periph, 1, (u_int32_t *) arg);
1257                 break;
1258         case MTIOCSLOCATE:
1259                 PENDING_MOUNT_CHECK(softc, periph, dev);
1260                 error = sasetpos(periph, 0, (u_int32_t *) arg);
1261                 break;
1262         case MTIOCHLOCATE:
1263                 PENDING_MOUNT_CHECK(softc, periph, dev);
1264                 error = sasetpos(periph, 1, (u_int32_t *) arg);
1265                 break;
1266         case MTIOCGETEOTMODEL:
1267                 error = 0;
1268                 if (softc->quirks & SA_QUIRK_1FM)
1269                         mode = 1;
1270                 else
1271                         mode = 2;
1272                 *((u_int32_t *) arg) = mode;
1273                 break;
1274         case MTIOCSETEOTMODEL:
1275                 error = 0;
1276                 switch (*((u_int32_t *) arg)) {
1277                 case 1:
1278                         softc->quirks &= ~SA_QUIRK_2FM;
1279                         softc->quirks |= SA_QUIRK_1FM;
1280                         break;
1281                 case 2:
1282                         softc->quirks &= ~SA_QUIRK_1FM;
1283                         softc->quirks |= SA_QUIRK_2FM;
1284                         break;
1285                 default:
1286                         error = EINVAL;
1287                         break;
1288                 }
1289                 break;
1290         default:
1291                 error = cam_periph_ioctl(periph, cmd, arg, saerror);
1292                 break;
1293         }
1294
1295         /*
1296          * Check to see if we cleared a frozen state
1297          */
1298         if (error == 0 && (softc->flags & SA_FLAG_TAPE_FROZEN)) {
1299                 switch(cmd) {
1300                 case MTIOCRDSPOS:
1301                 case MTIOCRDHPOS:
1302                 case MTIOCSLOCATE:
1303                 case MTIOCHLOCATE:
1304                         softc->fileno = (daddr_t) -1;
1305                         softc->blkno = (daddr_t) -1;
1306                         softc->flags &= ~SA_FLAG_TAPE_FROZEN;
1307                         xpt_print(periph->path,
1308                             "tape state now unfrozen.\n");
1309                         break;
1310                 default:
1311                         break;
1312                 }
1313         }
1314         if (didlockperiph) {
1315                 cam_periph_unhold(periph);
1316         }
1317         cam_periph_unlock(periph);
1318         return (error);
1319 }
1320
1321 static void
1322 sainit(void)
1323 {
1324         cam_status status;
1325
1326         /*
1327          * Install a global async callback.
1328          */
1329         status = xpt_register_async(AC_FOUND_DEVICE, saasync, NULL, NULL);
1330
1331         if (status != CAM_REQ_CMP) {
1332                 printf("sa: Failed to attach master async callback "
1333                        "due to status 0x%x!\n", status);
1334         }
1335 }
1336
1337 static void
1338 saoninvalidate(struct cam_periph *periph)
1339 {
1340         struct sa_softc *softc;
1341
1342         softc = (struct sa_softc *)periph->softc;
1343
1344         /*
1345          * De-register any async callbacks.
1346          */
1347         xpt_register_async(0, saasync, periph, periph->path);
1348
1349         softc->flags |= SA_FLAG_INVALID;
1350
1351         /*
1352          * Return all queued I/O with ENXIO.
1353          * XXX Handle any transactions queued to the card
1354          *     with XPT_ABORT_CCB.
1355          */
1356         bioq_flush(&softc->bio_queue, NULL, ENXIO);
1357         softc->queue_count = 0;
1358
1359         xpt_print(periph->path, "lost device\n");
1360
1361 }
1362
1363 static void
1364 sacleanup(struct cam_periph *periph)
1365 {
1366         struct sa_softc *softc;
1367         int i;
1368
1369         softc = (struct sa_softc *)periph->softc;
1370
1371         xpt_print(periph->path, "removing device entry\n");
1372         devstat_remove_entry(softc->device_stats);
1373         cam_periph_unlock(periph);
1374         destroy_dev(softc->devs.ctl_dev);
1375         for (i = 0; i < SA_NUM_MODES; i++) {
1376                 destroy_dev(softc->devs.mode_devs[i].r_dev);
1377                 destroy_dev(softc->devs.mode_devs[i].nr_dev);
1378                 destroy_dev(softc->devs.mode_devs[i].er_dev);
1379         }
1380         cam_periph_lock(periph);
1381         free(softc, M_SCSISA);
1382 }
1383
1384 static void
1385 saasync(void *callback_arg, u_int32_t code,
1386         struct cam_path *path, void *arg)
1387 {
1388         struct cam_periph *periph;
1389
1390         periph = (struct cam_periph *)callback_arg;
1391         switch (code) {
1392         case AC_FOUND_DEVICE:
1393         {
1394                 struct ccb_getdev *cgd;
1395                 cam_status status;
1396
1397                 cgd = (struct ccb_getdev *)arg;
1398                 if (cgd == NULL)
1399                         break;
1400
1401                 if (cgd->protocol != PROTO_SCSI)
1402                         break;
1403
1404                 if (SID_TYPE(&cgd->inq_data) != T_SEQUENTIAL)
1405                         break;
1406
1407                 /*
1408                  * Allocate a peripheral instance for
1409                  * this device and start the probe
1410                  * process.
1411                  */
1412                 status = cam_periph_alloc(saregister, saoninvalidate,
1413                                           sacleanup, sastart,
1414                                           "sa", CAM_PERIPH_BIO, cgd->ccb_h.path,
1415                                           saasync, AC_FOUND_DEVICE, cgd);
1416
1417                 if (status != CAM_REQ_CMP
1418                  && status != CAM_REQ_INPROG)
1419                         printf("saasync: Unable to probe new device "
1420                                 "due to status 0x%x\n", status);
1421                 break;
1422         }
1423         default:
1424                 cam_periph_async(periph, code, path, arg);
1425                 break;
1426         }
1427 }
1428
1429 static cam_status
1430 saregister(struct cam_periph *periph, void *arg)
1431 {
1432         struct sa_softc *softc;
1433         struct ccb_getdev *cgd;
1434         caddr_t match;
1435         int i;
1436         
1437         cgd = (struct ccb_getdev *)arg;
1438         if (periph == NULL) {
1439                 printf("saregister: periph was NULL!!\n");
1440                 return (CAM_REQ_CMP_ERR);
1441         }
1442
1443         if (cgd == NULL) {
1444                 printf("saregister: no getdev CCB, can't register device\n");
1445                 return (CAM_REQ_CMP_ERR);
1446         }
1447
1448         softc = (struct sa_softc *)
1449             malloc(sizeof (*softc), M_SCSISA, M_NOWAIT | M_ZERO);
1450         if (softc == NULL) {
1451                 printf("saregister: Unable to probe new device. "
1452                        "Unable to allocate softc\n");                           
1453                 return (CAM_REQ_CMP_ERR);
1454         }
1455         softc->scsi_rev = SID_ANSI_REV(&cgd->inq_data);
1456         softc->state = SA_STATE_NORMAL;
1457         softc->fileno = (daddr_t) -1;
1458         softc->blkno = (daddr_t) -1;
1459
1460         bioq_init(&softc->bio_queue);
1461         periph->softc = softc;
1462
1463         /*
1464          * See if this device has any quirks.
1465          */
1466         match = cam_quirkmatch((caddr_t)&cgd->inq_data,
1467                                (caddr_t)sa_quirk_table,
1468                                sizeof(sa_quirk_table)/sizeof(*sa_quirk_table),
1469                                sizeof(*sa_quirk_table), scsi_inquiry_match);
1470
1471         if (match != NULL) {
1472                 softc->quirks = ((struct sa_quirk_entry *)match)->quirks;
1473                 softc->last_media_blksize =
1474                     ((struct sa_quirk_entry *)match)->prefblk;
1475 #ifdef  CAMDEBUG
1476                 xpt_print(periph->path, "found quirk entry %d\n",
1477                     (int) (((struct sa_quirk_entry *) match) - sa_quirk_table));
1478 #endif
1479         } else
1480                 softc->quirks = SA_QUIRK_NONE;
1481
1482         /*
1483          * The SA driver supports a blocksize, but we don't know the
1484          * blocksize until we media is inserted.  So, set a flag to
1485          * indicate that the blocksize is unavailable right now.
1486          */
1487         cam_periph_unlock(periph);
1488         softc->device_stats = devstat_new_entry("sa", periph->unit_number, 0,
1489             DEVSTAT_BS_UNAVAILABLE, SID_TYPE(&cgd->inq_data) |
1490             DEVSTAT_TYPE_IF_SCSI, DEVSTAT_PRIORITY_TAPE);
1491
1492         softc->devs.ctl_dev = make_dev(&sa_cdevsw, SAMINOR(SA_CTLDEV,
1493             0, SA_ATYPE_R), UID_ROOT, GID_OPERATOR,
1494             0660, "%s%d.ctl", periph->periph_name, periph->unit_number);
1495         softc->devs.ctl_dev->si_drv1 = periph;
1496
1497         for (i = 0; i < SA_NUM_MODES; i++) {
1498
1499                 softc->devs.mode_devs[i].r_dev = make_dev(&sa_cdevsw,
1500                     SAMINOR(SA_NOT_CTLDEV, i, SA_ATYPE_R),
1501                     UID_ROOT, GID_OPERATOR, 0660, "%s%d.%d",
1502                     periph->periph_name, periph->unit_number, i);
1503                 softc->devs.mode_devs[i].r_dev->si_drv1 = periph;
1504
1505                 softc->devs.mode_devs[i].nr_dev = make_dev(&sa_cdevsw,
1506                     SAMINOR(SA_NOT_CTLDEV, i, SA_ATYPE_NR),
1507                     UID_ROOT, GID_OPERATOR, 0660, "n%s%d.%d",
1508                     periph->periph_name, periph->unit_number, i);
1509                 softc->devs.mode_devs[i].nr_dev->si_drv1 = periph;
1510
1511                 softc->devs.mode_devs[i].er_dev = make_dev(&sa_cdevsw,
1512                     SAMINOR(SA_NOT_CTLDEV, i, SA_ATYPE_ER),
1513                     UID_ROOT, GID_OPERATOR, 0660, "e%s%d.%d",
1514                     periph->periph_name, periph->unit_number, i);
1515                 softc->devs.mode_devs[i].er_dev->si_drv1 = periph;
1516
1517                 /*
1518                  * Make the (well known) aliases for the first mode.
1519                  */
1520                 if (i == 0) {
1521                         struct cdev *alias;
1522
1523                         alias = make_dev_alias(softc->devs.mode_devs[i].r_dev,
1524                            "%s%d", periph->periph_name, periph->unit_number);
1525                         alias->si_drv1 = periph;
1526                         alias = make_dev_alias(softc->devs.mode_devs[i].nr_dev,
1527                             "n%s%d", periph->periph_name, periph->unit_number);
1528                         alias->si_drv1 = periph;
1529                         alias = make_dev_alias(softc->devs.mode_devs[i].er_dev,
1530                             "e%s%d", periph->periph_name, periph->unit_number);
1531                         alias->si_drv1 = periph;
1532                 }
1533         }
1534         cam_periph_lock(periph);
1535
1536         /*
1537          * Add an async callback so that we get
1538          * notified if this device goes away.
1539          */
1540         xpt_register_async(AC_LOST_DEVICE, saasync, periph, periph->path);
1541
1542         xpt_announce_periph(periph, NULL);
1543
1544         return (CAM_REQ_CMP);
1545 }
1546
1547 static void
1548 sastart(struct cam_periph *periph, union ccb *start_ccb)
1549 {
1550         struct sa_softc *softc;
1551
1552         softc = (struct sa_softc *)periph->softc;
1553
1554         CAM_DEBUG(periph->path, CAM_DEBUG_TRACE, ("sastart\n"));
1555
1556         
1557         switch (softc->state) {
1558         case SA_STATE_NORMAL:
1559         {
1560                 /* Pull a buffer from the queue and get going on it */          
1561                 struct bio *bp;
1562
1563                 /*
1564                  * See if there is a buf with work for us to do..
1565                  */
1566                 bp = bioq_first(&softc->bio_queue);
1567                 if (periph->immediate_priority <= periph->pinfo.priority) {
1568                         CAM_DEBUG_PRINT(CAM_DEBUG_SUBTRACE,
1569                                         ("queuing for immediate ccb\n"));
1570                         Set_CCB_Type(start_ccb, SA_CCB_WAITING);
1571                         SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
1572                                           periph_links.sle);
1573                         periph->immediate_priority = CAM_PRIORITY_NONE;
1574                         wakeup(&periph->ccb_list);
1575                 } else if (bp == NULL) {
1576                         xpt_release_ccb(start_ccb);
1577                 } else if ((softc->flags & SA_FLAG_ERR_PENDING) != 0) {
1578                         struct bio *done_bp;
1579 again:
1580                         softc->queue_count--;
1581                         bioq_remove(&softc->bio_queue, bp);
1582                         bp->bio_resid = bp->bio_bcount;
1583                         done_bp = bp;
1584                         if ((softc->flags & SA_FLAG_EOM_PENDING) != 0) {
1585                                 /*
1586                                  * We now just clear errors in this case
1587                                  * and let the residual be the notifier.
1588                                  */
1589                                 bp->bio_error = 0;
1590                         } else if ((softc->flags & SA_FLAG_EOF_PENDING) != 0) {
1591                                 /*
1592                                  * This can only happen if we're reading
1593                                  * in fixed length mode. In this case,
1594                                  * we dump the rest of the list the
1595                                  * same way.
1596                                  */
1597                                 bp->bio_error = 0;
1598                                 if (bioq_first(&softc->bio_queue) != NULL) {
1599                                         biodone(done_bp);
1600                                         goto again;
1601                                 }
1602                         } else if ((softc->flags & SA_FLAG_EIO_PENDING) != 0) {
1603                                 bp->bio_error = EIO;
1604                                 bp->bio_flags |= BIO_ERROR;
1605                         }
1606                         bp = bioq_first(&softc->bio_queue);
1607                         /*
1608                          * Only if we have no other buffers queued up
1609                          * do we clear the pending error flag.
1610                          */
1611                         if (bp == NULL)
1612                                 softc->flags &= ~SA_FLAG_ERR_PENDING;
1613                         CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
1614                             ("sastart- ERR_PENDING now 0x%x, bp is %sNULL, "
1615                             "%d more buffers queued up\n",
1616                             (softc->flags & SA_FLAG_ERR_PENDING),
1617                             (bp != NULL)? "not " : " ", softc->queue_count));
1618                         xpt_release_ccb(start_ccb);
1619                         biodone(done_bp);
1620                 } else {
1621                         u_int32_t length;
1622
1623                         bioq_remove(&softc->bio_queue, bp);
1624                         softc->queue_count--;
1625
1626                         if ((softc->flags & SA_FLAG_FIXED) != 0) {
1627                                 if (softc->blk_shift != 0) {
1628                                         length =
1629                                             bp->bio_bcount >> softc->blk_shift;
1630                                 } else if (softc->media_blksize != 0) {
1631                                         length = bp->bio_bcount /
1632                                             softc->media_blksize;
1633                                 } else {
1634                                         bp->bio_error = EIO;
1635                                         xpt_print(periph->path, "zero blocksize"
1636                                             " for FIXED length writes?\n");
1637                                         biodone(bp);
1638                                         break;
1639                                 }
1640 #if     0
1641                                 CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_INFO,
1642                                     ("issuing a %d fixed record %s\n",
1643                                     length,  (bp->bio_cmd == BIO_READ)? "read" :
1644                                     "write"));
1645 #endif
1646                         } else {
1647                                 length = bp->bio_bcount;
1648 #if     0
1649                                 CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_INFO,
1650                                     ("issuing a %d variable byte %s\n",
1651                                     length,  (bp->bio_cmd == BIO_READ)? "read" :
1652                                     "write"));
1653 #endif
1654                         }
1655                         devstat_start_transaction_bio(softc->device_stats, bp);
1656                         /*
1657                          * Some people have theorized that we should
1658                          * suppress illegal length indication if we are
1659                          * running in variable block mode so that we don't
1660                          * have to request sense every time our requested
1661                          * block size is larger than the written block.
1662                          * The residual information from the ccb allows
1663                          * us to identify this situation anyway.  The only
1664                          * problem with this is that we will not get
1665                          * information about blocks that are larger than
1666                          * our read buffer unless we set the block size
1667                          * in the mode page to something other than 0.
1668                          *
1669                          * I believe that this is a non-issue. If user apps
1670                          * don't adjust their read size to match our record
1671                          * size, that's just life. Anyway, the typical usage
1672                          * would be to issue, e.g., 64KB reads and occasionally
1673                          * have to do deal with 512 byte or 1KB intermediate
1674                          * records.
1675                          */
1676                         softc->dsreg = (bp->bio_cmd == BIO_READ)?
1677                             MTIO_DSREG_RD : MTIO_DSREG_WR;
1678                         scsi_sa_read_write(&start_ccb->csio, 0, sadone,
1679                             MSG_SIMPLE_Q_TAG, (bp->bio_cmd == BIO_READ),
1680                             FALSE, (softc->flags & SA_FLAG_FIXED) != 0,
1681                             length, bp->bio_data, bp->bio_bcount, SSD_FULL_SIZE,
1682                             IO_TIMEOUT);
1683                         start_ccb->ccb_h.ccb_pflags &= ~SA_POSITION_UPDATED;
1684                         Set_CCB_Type(start_ccb, SA_CCB_BUFFER_IO);
1685                         start_ccb->ccb_h.ccb_bp = bp;
1686                         bp = bioq_first(&softc->bio_queue);
1687                         xpt_action(start_ccb);
1688                 }
1689                 
1690                 if (bp != NULL) {
1691                         /* Have more work to do, so ensure we stay scheduled */
1692                         xpt_schedule(periph, CAM_PRIORITY_NORMAL);
1693                 }
1694                 break;
1695         }
1696         case SA_STATE_ABNORMAL:
1697         default:
1698                 panic("state 0x%x in sastart", softc->state);
1699                 break;
1700         }
1701 }
1702
1703
1704 static void
1705 sadone(struct cam_periph *periph, union ccb *done_ccb)
1706 {
1707         struct sa_softc *softc;
1708         struct ccb_scsiio *csio;
1709
1710         softc = (struct sa_softc *)periph->softc;
1711         csio = &done_ccb->csio;
1712         switch (CCB_Type(csio)) {
1713         case SA_CCB_BUFFER_IO:
1714         {
1715                 struct bio *bp;
1716                 int error;
1717
1718                 softc->dsreg = MTIO_DSREG_REST;
1719                 bp = (struct bio *)done_ccb->ccb_h.ccb_bp;
1720                 error = 0;
1721                 if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
1722                         if ((error = saerror(done_ccb, 0, 0)) == ERESTART) {
1723                                 /*
1724                                  * A retry was scheduled, so just return.
1725                                  */
1726                                 return;
1727                         }
1728                 }
1729
1730                 if (error == EIO) {
1731
1732                         /*
1733                          * Catastrophic error. Mark the tape as frozen
1734                          * (we no longer know tape position).
1735                          *
1736                          * Return all queued I/O with EIO, and unfreeze
1737                          * our queue so that future transactions that
1738                          * attempt to fix this problem can get to the
1739                          * device.
1740                          *
1741                          */
1742
1743                         softc->flags |= SA_FLAG_TAPE_FROZEN;
1744                         bioq_flush(&softc->bio_queue, NULL, EIO);
1745                 }
1746                 if (error != 0) {
1747                         bp->bio_resid = bp->bio_bcount;
1748                         bp->bio_error = error;
1749                         bp->bio_flags |= BIO_ERROR;
1750                         /*
1751                          * In the error case, position is updated in saerror.
1752                          */
1753                 } else {
1754                         bp->bio_resid = csio->resid;
1755                         bp->bio_error = 0;
1756                         if (csio->resid != 0) {
1757                                 bp->bio_flags |= BIO_ERROR;
1758                         }
1759                         if (bp->bio_cmd == BIO_WRITE) {
1760                                 softc->flags |= SA_FLAG_TAPE_WRITTEN;
1761                                 softc->filemarks = 0;
1762                         }
1763                         if (!(csio->ccb_h.ccb_pflags & SA_POSITION_UPDATED) &&
1764                             (softc->blkno != (daddr_t) -1)) {
1765                                 if ((softc->flags & SA_FLAG_FIXED) != 0) {
1766                                         u_int32_t l;
1767                                         if (softc->blk_shift != 0) {
1768                                                 l = bp->bio_bcount >>
1769                                                         softc->blk_shift;
1770                                         } else {
1771                                                 l = bp->bio_bcount /
1772                                                         softc->media_blksize;
1773                                         }
1774                                         softc->blkno += (daddr_t) l;
1775                                 } else {
1776                                         softc->blkno++;
1777                                 }
1778                         }
1779                 }
1780                 /*
1781                  * If we had an error (immediate or pending),
1782                  * release the device queue now.
1783                  */
1784                 if (error || (softc->flags & SA_FLAG_ERR_PENDING))
1785                         cam_release_devq(done_ccb->ccb_h.path, 0, 0, 0, 0);
1786 #ifdef  CAMDEBUG
1787                 if (error || bp->bio_resid) {
1788                         CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
1789                                   ("error %d resid %ld count %ld\n", error,
1790                                   bp->bio_resid, bp->bio_bcount));
1791                 }
1792 #endif
1793                 biofinish(bp, softc->device_stats, 0);
1794                 break;
1795         }
1796         case SA_CCB_WAITING:
1797         {
1798                 /* Caller will release the CCB */
1799                 wakeup(&done_ccb->ccb_h.cbfcnp);
1800                 return;
1801         }
1802         }
1803         xpt_release_ccb(done_ccb);
1804 }
1805
1806 /*
1807  * Mount the tape (make sure it's ready for I/O).
1808  */
1809 static int
1810 samount(struct cam_periph *periph, int oflags, struct cdev *dev)
1811 {
1812         struct  sa_softc *softc;
1813         union   ccb *ccb;
1814         int     error;
1815
1816         /*
1817          * oflags can be checked for 'kind' of open (read-only check) - later
1818          * dev can be checked for a control-mode or compression open - later
1819          */
1820         UNUSED_PARAMETER(oflags);
1821         UNUSED_PARAMETER(dev);
1822
1823
1824         softc = (struct sa_softc *)periph->softc;
1825
1826         /*
1827          * This should determine if something has happend since the last
1828          * open/mount that would invalidate the mount. We do *not* want
1829          * to retry this command- we just want the status. But we only
1830          * do this if we're mounted already- if we're not mounted,
1831          * we don't care about the unit read state and can instead use
1832          * this opportunity to attempt to reserve the tape unit.
1833          */
1834         
1835         if (softc->flags & SA_FLAG_TAPE_MOUNTED) {
1836                 ccb = cam_periph_getccb(periph, 1);
1837                 scsi_test_unit_ready(&ccb->csio, 0, sadone,
1838                     MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE, IO_TIMEOUT);
1839                 error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1840                     softc->device_stats);
1841                 QFRLS(ccb);
1842                 if (error == ENXIO) {
1843                         softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
1844                         scsi_test_unit_ready(&ccb->csio, 0, sadone,
1845                             MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE, IO_TIMEOUT);
1846                         error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1847                             softc->device_stats);
1848                         QFRLS(ccb);
1849                 } else if (error) {
1850                         /*
1851                          * We don't need to freeze the tape because we
1852                          * will now attempt to rewind/load it.
1853                          */
1854                         softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
1855                         if (CAM_DEBUGGED(periph->path, CAM_DEBUG_INFO)) {
1856                                 xpt_print(periph->path,
1857                                     "error %d on TUR in samount\n", error);
1858                         }
1859                 }
1860         } else {
1861                 error = sareservereleaseunit(periph, TRUE);
1862                 if (error) {
1863                         return (error);
1864                 }
1865                 ccb = cam_periph_getccb(periph, 1);
1866                 scsi_test_unit_ready(&ccb->csio, 0, sadone,
1867                     MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE, IO_TIMEOUT);
1868                 error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1869                     softc->device_stats);
1870                 QFRLS(ccb);
1871         }
1872
1873         if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0) {
1874                 struct scsi_read_block_limits_data *rblim = NULL;
1875                 int comp_enabled, comp_supported;
1876                 u_int8_t write_protect, guessing = 0;
1877
1878                 /*
1879                  * Clear out old state.
1880                  */
1881                 softc->flags &= ~(SA_FLAG_TAPE_WP|SA_FLAG_TAPE_WRITTEN|
1882                                   SA_FLAG_ERR_PENDING|SA_FLAG_COMP_ENABLED|
1883                                   SA_FLAG_COMP_SUPP|SA_FLAG_COMP_UNSUPP);
1884                 softc->filemarks = 0;
1885
1886                 /*
1887                  * *Very* first off, make sure we're loaded to BOT.
1888                  */
1889                 scsi_load_unload(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG, FALSE,
1890                     FALSE, FALSE, 1, SSD_FULL_SIZE, REWIND_TIMEOUT);
1891                 error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1892                     softc->device_stats);
1893                 QFRLS(ccb);
1894
1895                 /*
1896                  * In case this doesn't work, do a REWIND instead
1897                  */
1898                 if (error) {
1899                         scsi_rewind(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG,
1900                             FALSE, SSD_FULL_SIZE, REWIND_TIMEOUT);
1901                         error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1902                                 softc->device_stats);
1903                         QFRLS(ccb);
1904                 }
1905                 if (error) {
1906                         xpt_release_ccb(ccb);
1907                         goto exit;
1908                 }
1909
1910                 /*
1911                  * Do a dummy test read to force access to the
1912                  * media so that the drive will really know what's
1913                  * there. We actually don't really care what the
1914                  * blocksize on tape is and don't expect to really
1915                  * read a full record.
1916                  */
1917                 rblim = (struct  scsi_read_block_limits_data *)
1918                     malloc(8192, M_SCSISA, M_NOWAIT);
1919                 if (rblim == NULL) {
1920                         xpt_print(periph->path, "no memory for test read\n");
1921                         xpt_release_ccb(ccb);
1922                         error = ENOMEM;
1923                         goto exit;
1924                 }
1925
1926                 if ((softc->quirks & SA_QUIRK_NODREAD) == 0) {
1927                         scsi_sa_read_write(&ccb->csio, 0, sadone,
1928                             MSG_SIMPLE_Q_TAG, 1, FALSE, 0, 8192,
1929                             (void *) rblim, 8192, SSD_FULL_SIZE,
1930                             IO_TIMEOUT);
1931                         (void) cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
1932                             softc->device_stats);
1933                         QFRLS(ccb);
1934                         scsi_rewind(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG,
1935                             FALSE, SSD_FULL_SIZE, REWIND_TIMEOUT);
1936                         error = cam_periph_runccb(ccb, saerror, CAM_RETRY_SELTO,
1937                             SF_NO_PRINT | SF_RETRY_UA,
1938                             softc->device_stats);
1939                         QFRLS(ccb);
1940                         if (error) {
1941                                 xpt_print(periph->path,
1942                                     "unable to rewind after test read\n");
1943                                 xpt_release_ccb(ccb);
1944                                 goto exit;
1945                         }
1946                 }
1947
1948                 /*
1949                  * Next off, determine block limits.
1950                  */
1951                 scsi_read_block_limits(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG,
1952                     rblim, SSD_FULL_SIZE, SCSIOP_TIMEOUT);
1953
1954                 error = cam_periph_runccb(ccb, saerror, CAM_RETRY_SELTO,
1955                     SF_NO_PRINT | SF_RETRY_UA, softc->device_stats);
1956
1957                 QFRLS(ccb);
1958                 xpt_release_ccb(ccb);
1959
1960                 if (error != 0) {
1961                         /*
1962                          * If it's less than SCSI-2, READ BLOCK LIMITS is not
1963                          * a MANDATORY command. Anyway- it doesn't matter-
1964                          * we can proceed anyway.
1965                          */
1966                         softc->blk_gran = 0;
1967                         softc->max_blk = ~0;
1968                         softc->min_blk = 0;
1969                 } else {
1970                         if (softc->scsi_rev >= SCSI_REV_SPC) {
1971                                 softc->blk_gran = RBL_GRAN(rblim);
1972                         } else {
1973                                 softc->blk_gran = 0;
1974                         }
1975                         /*
1976                          * We take max_blk == min_blk to mean a default to
1977                          * fixed mode- but note that whatever we get out of
1978                          * sagetparams below will actually determine whether
1979                          * we are actually *in* fixed mode.
1980                          */
1981                         softc->max_blk = scsi_3btoul(rblim->maximum);
1982                         softc->min_blk = scsi_2btoul(rblim->minimum);
1983
1984
1985                 }
1986                 /*
1987                  * Next, perform a mode sense to determine
1988                  * current density, blocksize, compression etc.
1989                  */
1990                 error = sagetparams(periph, SA_PARAM_ALL,
1991                                     &softc->media_blksize,
1992                                     &softc->media_density,
1993                                     &softc->media_numblks,
1994                                     &softc->buffer_mode, &write_protect,
1995                                     &softc->speed, &comp_supported,
1996                                     &comp_enabled, &softc->comp_algorithm,
1997                                     NULL);
1998
1999                 if (error != 0) {
2000                         /*
2001                          * We could work a little harder here. We could
2002                          * adjust our attempts to get information. It
2003                          * might be an ancient tape drive. If someone
2004                          * nudges us, we'll do that.
2005                          */
2006                         goto exit;
2007                 }
2008
2009                 /*
2010                  * If no quirk has determined that this is a device that is
2011                  * preferred to be in fixed or variable mode, now is the time
2012                  * to find out.
2013                  */
2014                 if ((softc->quirks & (SA_QUIRK_FIXED|SA_QUIRK_VARIABLE)) == 0) {
2015                         guessing = 1;
2016                         /*
2017                          * This could be expensive to find out. Luckily we
2018                          * only need to do this once. If we start out in
2019                          * 'default' mode, try and set ourselves to one
2020                          * of the densities that would determine a wad
2021                          * of other stuff. Go from highest to lowest.
2022                          */
2023                         if (softc->media_density == SCSI_DEFAULT_DENSITY) {
2024                                 int i;
2025                                 static u_int8_t ctry[] = {
2026                                         SCSI_DENSITY_HALFINCH_PE,
2027                                         SCSI_DENSITY_HALFINCH_6250C,
2028                                         SCSI_DENSITY_HALFINCH_6250,
2029                                         SCSI_DENSITY_HALFINCH_1600,
2030                                         SCSI_DENSITY_HALFINCH_800,
2031                                         SCSI_DENSITY_QIC_4GB,
2032                                         SCSI_DENSITY_QIC_2GB,
2033                                         SCSI_DENSITY_QIC_525_320,
2034                                         SCSI_DENSITY_QIC_150,
2035                                         SCSI_DENSITY_QIC_120,
2036                                         SCSI_DENSITY_QIC_24,
2037                                         SCSI_DENSITY_QIC_11_9TRK,
2038                                         SCSI_DENSITY_QIC_11_4TRK,
2039                                         SCSI_DENSITY_QIC_1320,
2040                                         SCSI_DENSITY_QIC_3080,
2041                                         0
2042                                 };
2043                                 for (i = 0; ctry[i]; i++) {
2044                                         error = sasetparams(periph,
2045                                             SA_PARAM_DENSITY, 0, ctry[i],
2046                                             0, SF_NO_PRINT);
2047                                         if (error == 0) {
2048                                                 softc->media_density = ctry[i];
2049                                                 break;
2050                                         }
2051                                 }
2052                         }
2053                         switch (softc->media_density) {
2054                         case SCSI_DENSITY_QIC_11_4TRK:
2055                         case SCSI_DENSITY_QIC_11_9TRK:
2056                         case SCSI_DENSITY_QIC_24:
2057                         case SCSI_DENSITY_QIC_120:
2058                         case SCSI_DENSITY_QIC_150:
2059                         case SCSI_DENSITY_QIC_525_320:
2060                         case SCSI_DENSITY_QIC_1320:
2061                         case SCSI_DENSITY_QIC_3080:
2062                                 softc->quirks &= ~SA_QUIRK_2FM;
2063                                 softc->quirks |= SA_QUIRK_FIXED|SA_QUIRK_1FM;
2064                                 softc->last_media_blksize = 512;
2065                                 break;
2066                         case SCSI_DENSITY_QIC_4GB:
2067                         case SCSI_DENSITY_QIC_2GB:
2068                                 softc->quirks &= ~SA_QUIRK_2FM;
2069                                 softc->quirks |= SA_QUIRK_FIXED|SA_QUIRK_1FM;
2070                                 softc->last_media_blksize = 1024;
2071                                 break;
2072                         default:
2073                                 softc->last_media_blksize =
2074                                     softc->media_blksize;
2075                                 softc->quirks |= SA_QUIRK_VARIABLE;
2076                                 break;
2077                         }
2078                 }
2079
2080                 /*
2081                  * If no quirk has determined that this is a device that needs
2082                  * to have 2 Filemarks at EOD, now is the time to find out.
2083                  */
2084
2085                 if ((softc->quirks & SA_QUIRK_2FM) == 0) {
2086                         switch (softc->media_density) {
2087                         case SCSI_DENSITY_HALFINCH_800:
2088                         case SCSI_DENSITY_HALFINCH_1600:
2089                         case SCSI_DENSITY_HALFINCH_6250:
2090                         case SCSI_DENSITY_HALFINCH_6250C:
2091                         case SCSI_DENSITY_HALFINCH_PE:
2092                                 softc->quirks &= ~SA_QUIRK_1FM;
2093                                 softc->quirks |= SA_QUIRK_2FM;
2094                                 break;
2095                         default:
2096                                 break;
2097                         }
2098                 }
2099
2100                 /*
2101                  * Now validate that some info we got makes sense.
2102                  */
2103                 if ((softc->max_blk < softc->media_blksize) ||
2104                     (softc->min_blk > softc->media_blksize &&
2105                     softc->media_blksize)) {
2106                         xpt_print(periph->path,
2107                             "BLOCK LIMITS (%d..%d) could not match current "
2108                             "block settings (%d)- adjusting\n", softc->min_blk,
2109                             softc->max_blk, softc->media_blksize);
2110                         softc->max_blk = softc->min_blk =
2111                             softc->media_blksize;
2112                 }
2113
2114                 /*
2115                  * Now put ourselves into the right frame of mind based
2116                  * upon quirks...
2117                  */
2118 tryagain:
2119                 /*
2120                  * If we want to be in FIXED mode and our current blocksize
2121                  * is not equal to our last blocksize (if nonzero), try and
2122                  * set ourselves to this last blocksize (as the 'preferred'
2123                  * block size).  The initial quirkmatch at registry sets the
2124                  * initial 'last' blocksize. If, for whatever reason, this
2125                  * 'last' blocksize is zero, set the blocksize to 512,
2126                  * or min_blk if that's larger.
2127                  */
2128                 if ((softc->quirks & SA_QUIRK_FIXED) &&
2129                     (softc->quirks & SA_QUIRK_NO_MODESEL) == 0 &&
2130                     (softc->media_blksize != softc->last_media_blksize)) {
2131                         softc->media_blksize = softc->last_media_blksize;
2132                         if (softc->media_blksize == 0) {
2133                                 softc->media_blksize = 512;
2134                                 if (softc->media_blksize < softc->min_blk) {
2135                                         softc->media_blksize = softc->min_blk;
2136                                 }
2137                         }
2138                         error = sasetparams(periph, SA_PARAM_BLOCKSIZE,
2139                             softc->media_blksize, 0, 0, SF_NO_PRINT);
2140                         if (error) {
2141                                 xpt_print(periph->path,
2142                                     "unable to set fixed blocksize to %d\n",
2143                                     softc->media_blksize);
2144                                 goto exit;
2145                         }
2146                 }
2147
2148                 if ((softc->quirks & SA_QUIRK_VARIABLE) && 
2149                     (softc->media_blksize != 0)) {
2150                         softc->last_media_blksize = softc->media_blksize;
2151                         softc->media_blksize = 0;
2152                         error = sasetparams(periph, SA_PARAM_BLOCKSIZE,
2153                             0, 0, 0, SF_NO_PRINT);
2154                         if (error) {
2155                                 /*
2156                                  * If this fails and we were guessing, just
2157                                  * assume that we got it wrong and go try
2158                                  * fixed block mode. Don't even check against
2159                                  * density code at this point.
2160                                  */
2161                                 if (guessing) {
2162                                         softc->quirks &= ~SA_QUIRK_VARIABLE;
2163                                         softc->quirks |= SA_QUIRK_FIXED;
2164                                         if (softc->last_media_blksize == 0)
2165                                                 softc->last_media_blksize = 512;
2166                                         goto tryagain;
2167                                 }
2168                                 xpt_print(periph->path,
2169                                     "unable to set variable blocksize\n");
2170                                 goto exit;
2171                         }
2172                 }
2173
2174                 /*
2175                  * Now that we have the current block size,
2176                  * set up some parameters for sastart's usage.
2177                  */
2178                 if (softc->media_blksize) {
2179                         softc->flags |= SA_FLAG_FIXED;
2180                         if (powerof2(softc->media_blksize)) {
2181                                 softc->blk_shift =
2182                                     ffs(softc->media_blksize) - 1;
2183                                 softc->blk_mask = softc->media_blksize - 1;
2184                         } else {
2185                                 softc->blk_mask = ~0;
2186                                 softc->blk_shift = 0;
2187                         }
2188                 } else {
2189                         /*
2190                          * The SCSI-3 spec allows 0 to mean "unspecified".
2191                          * The SCSI-1 spec allows 0 to mean 'infinite'.
2192                          *
2193                          * Either works here.
2194                          */
2195                         if (softc->max_blk == 0) {
2196                                 softc->max_blk = ~0;
2197                         }
2198                         softc->blk_shift = 0;
2199                         if (softc->blk_gran != 0) {
2200                                 softc->blk_mask = softc->blk_gran - 1;
2201                         } else {
2202                                 softc->blk_mask = 0;
2203                         }
2204                 }
2205
2206                 if (write_protect) 
2207                         softc->flags |= SA_FLAG_TAPE_WP;
2208
2209                 if (comp_supported) {
2210                         if (softc->saved_comp_algorithm == 0)
2211                                 softc->saved_comp_algorithm =
2212                                     softc->comp_algorithm;
2213                         softc->flags |= SA_FLAG_COMP_SUPP;
2214                         if (comp_enabled)
2215                                 softc->flags |= SA_FLAG_COMP_ENABLED;
2216                 } else
2217                         softc->flags |= SA_FLAG_COMP_UNSUPP;
2218
2219                 if ((softc->buffer_mode == SMH_SA_BUF_MODE_NOBUF) &&
2220                     (softc->quirks & SA_QUIRK_NO_MODESEL) == 0) {
2221                         error = sasetparams(periph, SA_PARAM_BUFF_MODE, 0,
2222                             0, 0, SF_NO_PRINT);
2223                         if (error == 0) {
2224                                 softc->buffer_mode = SMH_SA_BUF_MODE_SIBUF;
2225                         } else {
2226                                 xpt_print(periph->path,
2227                                     "unable to set buffered mode\n");
2228                         }
2229                         error = 0;      /* not an error */
2230                 }
2231
2232
2233                 if (error == 0) {
2234                         softc->flags |= SA_FLAG_TAPE_MOUNTED;
2235                 }
2236 exit:
2237                 if (rblim != NULL)
2238                         free(rblim, M_SCSISA);
2239
2240                 if (error != 0) {
2241                         softc->dsreg = MTIO_DSREG_NIL;
2242                 } else {
2243                         softc->fileno = softc->blkno = 0;
2244                         softc->dsreg = MTIO_DSREG_REST;
2245                 }
2246 #ifdef  SA_1FM_AT_EOD
2247                 if ((softc->quirks & SA_QUIRK_2FM) == 0)
2248                         softc->quirks |= SA_QUIRK_1FM;
2249 #else
2250                 if ((softc->quirks & SA_QUIRK_1FM) == 0)
2251                         softc->quirks |= SA_QUIRK_2FM;
2252 #endif
2253         } else
2254                 xpt_release_ccb(ccb);
2255
2256         /*
2257          * If we return an error, we're not mounted any more,
2258          * so release any device reservation.
2259          */
2260         if (error != 0) {
2261                 (void) sareservereleaseunit(periph, FALSE);
2262         } else {
2263                 /*
2264                  * Clear I/O residual.
2265                  */
2266                 softc->last_io_resid = 0;
2267                 softc->last_ctl_resid = 0;
2268         }
2269         return (error);
2270 }
2271
2272 /*
2273  * How many filemarks do we need to write if we were to terminate the
2274  * tape session right now? Note that this can be a negative number
2275  */
2276
2277 static int
2278 samarkswanted(struct cam_periph *periph)
2279 {
2280         int     markswanted;
2281         struct  sa_softc *softc;
2282
2283         softc = (struct sa_softc *)periph->softc;
2284         markswanted = 0;
2285         if ((softc->flags & SA_FLAG_TAPE_WRITTEN) != 0) {
2286                 markswanted++;
2287                 if (softc->quirks & SA_QUIRK_2FM)
2288                         markswanted++;
2289         }
2290         markswanted -= softc->filemarks;
2291         return (markswanted);
2292 }
2293
2294 static int
2295 sacheckeod(struct cam_periph *periph)
2296 {
2297         int     error;
2298         int     markswanted;
2299
2300         markswanted = samarkswanted(periph);
2301
2302         if (markswanted > 0) {
2303                 error = sawritefilemarks(periph, markswanted, FALSE);
2304         } else {
2305                 error = 0;
2306         }
2307         return (error);
2308 }
2309
2310 static int
2311 saerror(union ccb *ccb, u_int32_t cflgs, u_int32_t sflgs)
2312 {
2313         static const char *toobig =
2314             "%d-byte tape record bigger than supplied buffer\n";
2315         struct  cam_periph *periph;
2316         struct  sa_softc *softc;
2317         struct  ccb_scsiio *csio;
2318         struct  scsi_sense_data *sense;
2319         u_int32_t resid = 0;
2320         int32_t info = 0;
2321         cam_status status;
2322         int error_code, sense_key, asc, ascq, error, aqvalid;
2323
2324         periph = xpt_path_periph(ccb->ccb_h.path);
2325         softc = (struct sa_softc *)periph->softc;
2326         csio = &ccb->csio;
2327         sense = &csio->sense_data;
2328         scsi_extract_sense(sense, &error_code, &sense_key, &asc, &ascq);
2329         aqvalid = sense->extra_len >= 6;
2330         error = 0;
2331
2332         status = csio->ccb_h.status & CAM_STATUS_MASK;
2333
2334         /*
2335          * Calculate/latch up, any residuals... We do this in a funny 2-step
2336          * so we can print stuff here if we have CAM_DEBUG enabled for this
2337          * unit.
2338          */
2339         if (status == CAM_SCSI_STATUS_ERROR) {
2340                 if ((sense->error_code & SSD_ERRCODE_VALID) != 0) {
2341                         info = (int32_t) scsi_4btoul(sense->info);
2342                         resid = info;
2343                         if ((softc->flags & SA_FLAG_FIXED) != 0)
2344                                 resid *= softc->media_blksize;
2345                 } else {
2346                         resid = csio->dxfer_len;
2347                         info = resid;
2348                         if ((softc->flags & SA_FLAG_FIXED) != 0) {
2349                                 if (softc->media_blksize)
2350                                         info /= softc->media_blksize;
2351                         }
2352                 }
2353                 if (CCB_Type(csio) == SA_CCB_BUFFER_IO) {
2354                         bcopy((caddr_t) sense, (caddr_t) &softc->last_io_sense,
2355                             sizeof (struct scsi_sense_data));
2356                         bcopy(csio->cdb_io.cdb_bytes, softc->last_io_cdb,
2357                             (int) csio->cdb_len);
2358                         softc->last_io_resid = resid;
2359                         softc->last_resid_was_io = 1;
2360                 } else {
2361                         bcopy((caddr_t) sense, (caddr_t) &softc->last_ctl_sense,
2362                             sizeof (struct scsi_sense_data));
2363                         bcopy(csio->cdb_io.cdb_bytes, softc->last_ctl_cdb,
2364                             (int) csio->cdb_len);
2365                         softc->last_ctl_resid = resid;
2366                         softc->last_resid_was_io = 0;
2367                 }
2368                 CAM_DEBUG(periph->path, CAM_DEBUG_INFO, ("CDB[0]=0x%x Key 0x%x "
2369                     "ASC/ASCQ 0x%x/0x%x CAM STATUS 0x%x flags 0x%x resid %d "
2370                     "dxfer_len %d\n", csio->cdb_io.cdb_bytes[0] & 0xff,
2371                     sense_key, asc, ascq, status,
2372                     sense->flags & ~SSD_KEY_RESERVED, resid, csio->dxfer_len));
2373         } else {
2374                 CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
2375                     ("Cam Status 0x%x\n", status));
2376         }
2377
2378         switch (status) {
2379         case CAM_REQ_CMP:
2380                 return (0);
2381         case CAM_SCSI_STATUS_ERROR:
2382                 /*
2383                  * If a read/write command, we handle it here.
2384                  */
2385                 if (CCB_Type(csio) != SA_CCB_WAITING) {
2386                         break;
2387                 }
2388                 /*
2389                  * If this was just EOM/EOP, Filemark, Setmark or ILI detected
2390                  * on a non read/write command, we assume it's not an error
2391                  * and propagate the residule and return.
2392                  */
2393                 if ((aqvalid && asc == 0 && ascq > 0 && ascq <= 5) ||
2394                     (aqvalid == 0 && sense_key == SSD_KEY_NO_SENSE)) {
2395                         csio->resid = resid;
2396                         QFRLS(ccb);
2397                         return (0);
2398                 }
2399                 /*
2400                  * Otherwise, we let the common code handle this.
2401                  */
2402                 return (cam_periph_error(ccb, cflgs, sflgs, &softc->saved_ccb));
2403
2404         /*
2405          * XXX: To Be Fixed
2406          * We cannot depend upon CAM honoring retry counts for these.
2407          */
2408         case CAM_SCSI_BUS_RESET:
2409         case CAM_BDR_SENT:
2410                 if (ccb->ccb_h.retry_count <= 0) {
2411                         return (EIO);
2412                 }
2413                 /* FALLTHROUGH */
2414         default:
2415                 return (cam_periph_error(ccb, cflgs, sflgs, &softc->saved_ccb));
2416         }
2417
2418         /*
2419          * Handle filemark, end of tape, mismatched record sizes....
2420          * From this point out, we're only handling read/write cases.
2421          * Handle writes && reads differently.
2422          */
2423
2424         if (csio->cdb_io.cdb_bytes[0] == SA_WRITE) {
2425                 if (sense_key == SSD_KEY_VOLUME_OVERFLOW) {
2426                         csio->resid = resid;
2427                         error = ENOSPC;
2428                 } else if (sense->flags & SSD_EOM) {
2429                         softc->flags |= SA_FLAG_EOM_PENDING;
2430                         /*
2431                          * Grotesque as it seems, the few times
2432                          * I've actually seen a non-zero resid,
2433                          * the tape drive actually lied and had
2434                          * written all the data!.
2435                          */
2436                         csio->resid = 0;
2437                 }
2438         } else {
2439                 csio->resid = resid;
2440             &n