Merge from vendor branch NCURSES:
[dragonfly.git] / sys / bus / cam / scsi / scsi_pass.c
1 /*
2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
3  * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions, and the following disclaimer,
11  *    without modification, immediately at the beginning of the file.
12  * 2. The name of the author may not be used to endorse or promote products
13  *    derived from this software without specific prior written permission.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
19  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD: src/sys/cam/scsi/scsi_pass.c,v 1.19 2000/01/17 06:27:37 mjacob Exp $
28  * $DragonFly: src/sys/bus/cam/scsi/scsi_pass.c,v 1.12 2004/05/19 22:52:38 dillon Exp $
29  */
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/types.h>
35 #include <sys/buf.h>
36 #include <sys/malloc.h>
37 #include <sys/fcntl.h>
38 #include <sys/stat.h>
39 #include <sys/conf.h>
40 #include <sys/buf.h>
41 #include <sys/proc.h>
42 #include <sys/errno.h>
43 #include <sys/devicestat.h>
44 #include <sys/proc.h>
45 #include <sys/buf2.h>
46
47 #include "../cam.h"
48 #include "../cam_ccb.h"
49 #include "../cam_extend.h"
50 #include "../cam_periph.h"
51 #include "../cam_xpt_periph.h"
52 #include "../cam_debug.h"
53
54 #include "scsi_all.h"
55 #include "scsi_message.h"
56 #include "scsi_da.h"
57 #include "scsi_pass.h"
58
59 typedef enum {
60         PASS_FLAG_OPEN                  = 0x01,
61         PASS_FLAG_LOCKED                = 0x02,
62         PASS_FLAG_INVALID               = 0x04
63 } pass_flags;
64
65 typedef enum {
66         PASS_STATE_NORMAL
67 } pass_state;
68
69 typedef enum {
70         PASS_CCB_BUFFER_IO,
71         PASS_CCB_WAITING
72 } pass_ccb_types;
73
74 #define ccb_type        ppriv_field0
75 #define ccb_bp          ppriv_ptr1
76
77 struct pass_softc {
78         pass_state      state;
79         pass_flags      flags;
80         u_int8_t        pd_type;
81         struct          buf_queue_head buf_queue;
82         union ccb       saved_ccb;
83         struct devstat  device_stats;
84 };
85
86 #define PASS_CDEV_MAJOR 31
87
88 static  d_open_t        passopen;
89 static  d_close_t       passclose;
90 static  d_ioctl_t       passioctl;
91 static  d_strategy_t    passstrategy;
92
93 static  periph_init_t   passinit;
94 static  periph_ctor_t   passregister;
95 static  periph_oninv_t  passoninvalidate;
96 static  periph_dtor_t   passcleanup;
97 static  periph_start_t  passstart;
98 static  void            passasync(void *callback_arg, u_int32_t code,
99                                   struct cam_path *path, void *arg);
100 static  void            passdone(struct cam_periph *periph, 
101                                  union ccb *done_ccb);
102 static  int             passerror(union ccb *ccb, u_int32_t cam_flags, 
103                                   u_int32_t sense_flags);
104 static  int             passsendccb(struct cam_periph *periph, union ccb *ccb,
105                                     union ccb *inccb);
106
107 static struct periph_driver passdriver =
108 {
109         passinit, "pass",
110         TAILQ_HEAD_INITIALIZER(passdriver.units), /* generation */ 0
111 };
112
113 DATA_SET(periphdriver_set, passdriver);
114
115 static struct cdevsw pass_cdevsw = {
116         /* name */      "pass",
117         /* maj */       PASS_CDEV_MAJOR,
118         /* flags */     0,
119         /* port */      NULL,
120         /* clone */     NULL,
121
122         /* open */      passopen,
123         /* close */     passclose,
124         /* read */      physread,
125         /* write */     physwrite,
126         /* ioctl */     passioctl,
127         /* poll */      nopoll,
128         /* mmap */      nommap,
129         /* strategy */  passstrategy,
130         /* dump */      nodump,
131         /* psize */     nopsize
132 };
133
134 static struct extend_array *passperiphs;
135
136 static void
137 passinit(void)
138 {
139         cam_status status;
140         struct cam_path *path;
141
142         /*
143          * Create our extend array for storing the devices we attach to.
144          */
145         passperiphs = cam_extend_new();
146         if (passperiphs == NULL) {
147                 printf("passm: Failed to alloc extend array!\n");
148                 return;
149         }
150
151         /*
152          * Install a global async callback.  This callback will
153          * receive async callbacks like "new device found".
154          */
155         status = xpt_create_path(&path, /*periph*/NULL, CAM_XPT_PATH_ID,
156                                  CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
157
158         if (status == CAM_REQ_CMP) {
159                 struct ccb_setasync csa;
160
161                 xpt_setup_ccb(&csa.ccb_h, path, /*priority*/5);
162                 csa.ccb_h.func_code = XPT_SASYNC_CB;
163                 csa.event_enable = AC_FOUND_DEVICE;
164                 csa.callback = passasync;
165                 csa.callback_arg = NULL;
166                 xpt_action((union ccb *)&csa);
167                 status = csa.ccb_h.status;
168                 xpt_free_path(path);
169         }
170
171         if (status != CAM_REQ_CMP) {
172                 printf("pass: Failed to attach master async callback "
173                        "due to status 0x%x!\n", status);
174         }
175         
176 }
177
178 static void
179 passoninvalidate(struct cam_periph *periph)
180 {
181         int s;
182         struct pass_softc *softc;
183         struct buf *q_bp;
184         struct ccb_setasync csa;
185
186         softc = (struct pass_softc *)periph->softc;
187
188         /*
189          * De-register any async callbacks.
190          */
191         xpt_setup_ccb(&csa.ccb_h, periph->path,
192                       /* priority */ 5);
193         csa.ccb_h.func_code = XPT_SASYNC_CB;
194         csa.event_enable = 0;
195         csa.callback = passasync;
196         csa.callback_arg = periph;
197         xpt_action((union ccb *)&csa);
198
199         softc->flags |= PASS_FLAG_INVALID;
200
201         /*
202          * Although the oninvalidate() routines are always called at
203          * splsoftcam, we need to be at splbio() here to keep the buffer
204          * queue from being modified while we traverse it.
205          */
206         s = splbio();
207
208         /*
209          * Return all queued I/O with ENXIO.
210          * XXX Handle any transactions queued to the card
211          *     with XPT_ABORT_CCB.
212          */
213         while ((q_bp = bufq_first(&softc->buf_queue)) != NULL){
214                 bufq_remove(&softc->buf_queue, q_bp);
215                 q_bp->b_resid = q_bp->b_bcount;
216                 q_bp->b_error = ENXIO;
217                 q_bp->b_flags |= B_ERROR;
218                 biodone(q_bp);
219         }
220         splx(s);
221
222         if (bootverbose) {
223                 xpt_print_path(periph->path);
224                 printf("lost device\n");
225         }
226
227 }
228
229 static void
230 passcleanup(struct cam_periph *periph)
231 {
232         struct pass_softc *softc;
233
234         softc = (struct pass_softc *)periph->softc;
235
236         devstat_remove_entry(&softc->device_stats);
237
238         cam_extend_release(passperiphs, periph->unit_number);
239
240         if (bootverbose) {
241                 xpt_print_path(periph->path);
242                 printf("removing device entry\n");
243         }
244         cdevsw_remove(&pass_cdevsw, -1, periph->unit_number);
245         free(softc, M_DEVBUF);
246 }
247
248 static void
249 passasync(void *callback_arg, u_int32_t code,
250           struct cam_path *path, void *arg)
251 {
252         struct cam_periph *periph;
253
254         periph = (struct cam_periph *)callback_arg;
255
256         switch (code) {
257         case AC_FOUND_DEVICE:
258         {
259                 struct ccb_getdev *cgd;
260                 cam_status status;
261  
262                 cgd = (struct ccb_getdev *)arg;
263
264                 /*
265                  * Allocate a peripheral instance for
266                  * this device and start the probe
267                  * process.
268                  */
269                 status = cam_periph_alloc(passregister, passoninvalidate,
270                                           passcleanup, passstart, "pass",
271                                           CAM_PERIPH_BIO, cgd->ccb_h.path,
272                                           passasync, AC_FOUND_DEVICE, cgd);
273
274                 if (status != CAM_REQ_CMP
275                  && status != CAM_REQ_INPROG)
276                         printf("passasync: Unable to attach new device "
277                                 "due to status 0x%x\n", status);
278
279                 break;
280         }
281         default:
282                 cam_periph_async(periph, code, path, arg);
283                 break;
284         }
285 }
286
287 static cam_status
288 passregister(struct cam_periph *periph, void *arg)
289 {
290         struct pass_softc *softc;
291         struct ccb_setasync csa;
292         struct ccb_getdev *cgd;
293
294         cgd = (struct ccb_getdev *)arg;
295         if (periph == NULL) {
296                 printf("passregister: periph was NULL!!\n");
297                 return(CAM_REQ_CMP_ERR);
298         }
299
300         if (cgd == NULL) {
301                 printf("passregister: no getdev CCB, can't register device\n");
302                 return(CAM_REQ_CMP_ERR);
303         }
304
305         softc = malloc(sizeof(*softc), M_DEVBUF, M_INTWAIT | M_ZERO);
306         softc->state = PASS_STATE_NORMAL;
307         softc->pd_type = SID_TYPE(&cgd->inq_data);
308         bufq_init(&softc->buf_queue);
309
310         periph->softc = softc;
311
312         cam_extend_set(passperiphs, periph->unit_number, periph);
313         /*
314          * We pass in 0 for a blocksize, since we don't 
315          * know what the blocksize of this device is, if 
316          * it even has a blocksize.
317          */
318         devstat_add_entry(&softc->device_stats, "pass", periph->unit_number,
319                           0, DEVSTAT_NO_BLOCKSIZE | DEVSTAT_NO_ORDERED_TAGS,
320                           softc->pd_type |
321                           DEVSTAT_TYPE_IF_SCSI |
322                           DEVSTAT_TYPE_PASS,
323                           DEVSTAT_PRIORITY_PASS);
324
325         /* Register the device */
326         cdevsw_add(&pass_cdevsw, -1, periph->unit_number);
327         make_dev(&pass_cdevsw, periph->unit_number, UID_ROOT,
328                   GID_OPERATOR, 0600, "%s%d", periph->periph_name,
329                   periph->unit_number);
330
331         /*
332          * Add an async callback so that we get
333          * notified if this device goes away.
334          */
335         xpt_setup_ccb(&csa.ccb_h, periph->path, /* priority */ 5);
336         csa.ccb_h.func_code = XPT_SASYNC_CB;
337         csa.event_enable = AC_LOST_DEVICE;
338         csa.callback = passasync;
339         csa.callback_arg = periph;
340         xpt_action((union ccb *)&csa);
341
342         if (bootverbose)
343                 xpt_announce_periph(periph, NULL);
344
345         return(CAM_REQ_CMP);
346 }
347
348 static int
349 passopen(dev_t dev, int flags, int fmt, struct thread *td)
350 {
351         struct cam_periph *periph;
352         struct pass_softc *softc;
353         int unit, error;
354         int s;
355
356         error = 0; /* default to no error */
357
358         /* unit = dkunit(dev); */
359         /* XXX KDM fix this */
360         unit = minor(dev) & 0xff;
361
362         periph = cam_extend_get(passperiphs, unit);
363
364         if (periph == NULL)
365                 return (ENXIO);
366
367         softc = (struct pass_softc *)periph->softc;
368
369         s = splsoftcam();
370         if (softc->flags & PASS_FLAG_INVALID) {
371                 splx(s);
372                 return(ENXIO);
373         }
374
375         /*
376          * Don't allow access when we're running at a high securelvel.
377          */
378         if (securelevel > 1) {
379                 splx(s);
380                 return(EPERM);
381         }
382
383         /*
384          * Only allow read-write access.
385          */
386         if (((flags & FWRITE) == 0) || ((flags & FREAD) == 0)) {
387                 splx(s);
388                 return(EPERM);
389         }
390
391         /*
392          * We don't allow nonblocking access.
393          */
394         if ((flags & O_NONBLOCK) != 0) {
395                 xpt_print_path(periph->path);
396                 printf("can't do nonblocking accesss\n");
397                 splx(s);
398                 return(EINVAL);
399         }
400
401         if ((error = cam_periph_lock(periph, PCATCH)) != 0) {
402                 splx(s);
403                 return (error);
404         }
405
406         splx(s);
407
408         if ((softc->flags & PASS_FLAG_OPEN) == 0) {
409                 if (cam_periph_acquire(periph) != CAM_REQ_CMP)
410                         return(ENXIO);
411                 softc->flags |= PASS_FLAG_OPEN;
412         }
413
414         cam_periph_unlock(periph);
415
416         return (error);
417 }
418
419 static int
420 passclose(dev_t dev, int flag, int fmt, struct thread *td)
421 {
422         struct  cam_periph *periph;
423         struct  pass_softc *softc;
424         int     unit, error;
425
426         /* unit = dkunit(dev); */
427         /* XXX KDM fix this */
428         unit = minor(dev) & 0xff;
429
430         periph = cam_extend_get(passperiphs, unit);
431         if (periph == NULL)
432                 return (ENXIO); 
433
434         softc = (struct pass_softc *)periph->softc;
435
436         if ((error = cam_periph_lock(periph, 0)) != 0)
437                 return (error);
438
439         softc->flags &= ~PASS_FLAG_OPEN;
440
441         cam_periph_unlock(periph);
442         cam_periph_release(periph);
443
444         return (0);
445 }
446
447 /*
448  * Actually translate the requested transfer into one the physical driver
449  * can understand.  The transfer is described by a buf and will include
450  * only one physical transfer.
451  */
452 static void
453 passstrategy(struct buf *bp)
454 {
455         struct cam_periph *periph;
456         struct pass_softc *softc;
457         u_int  unit;
458         int    s;
459
460         /*
461          * The read/write interface for the passthrough driver doesn't
462          * really work right now.  So, we just pass back EINVAL to tell the
463          * user to go away.
464          */
465         bp->b_error = EINVAL;
466         goto bad;
467
468         /* unit = dkunit(bp->b_dev); */
469         /* XXX KDM fix this */
470         unit = minor(bp->b_dev) & 0xff;
471
472         periph = cam_extend_get(passperiphs, unit);
473         if (periph == NULL) {
474                 bp->b_error = ENXIO;
475                 goto bad;
476         }
477         softc = (struct pass_softc *)periph->softc;
478
479         /*
480          * Odd number of bytes or negative offset
481          */
482         /* valid request?  */
483         if (bp->b_blkno < 0) {
484                 bp->b_error = EINVAL;
485                 goto bad;
486         }
487         
488         /*
489          * Mask interrupts so that the pack cannot be invalidated until
490          * after we are in the queue.  Otherwise, we might not properly
491          * clean up one of the buffers.
492          */
493         s = splbio();
494         
495         bufq_insert_tail(&softc->buf_queue, bp);
496
497         splx(s);
498         
499         /*
500          * Schedule ourselves for performing the work.
501          */
502         xpt_schedule(periph, /* XXX priority */1);
503
504         return;
505 bad:
506         bp->b_flags |= B_ERROR;
507
508         /*
509          * Correctly set the buf to indicate a completed xfer
510          */
511         bp->b_resid = bp->b_bcount;
512         biodone(bp);
513         return;
514 }
515
516 static void
517 passstart(struct cam_periph *periph, union ccb *start_ccb)
518 {
519         struct pass_softc *softc;
520         int s;
521
522         softc = (struct pass_softc *)periph->softc;
523
524         switch (softc->state) {
525         case PASS_STATE_NORMAL:
526         {
527                 struct buf *bp;
528
529                 s = splbio();
530                 bp = bufq_first(&softc->buf_queue);
531                 if (periph->immediate_priority <= periph->pinfo.priority) {
532                         start_ccb->ccb_h.ccb_type = PASS_CCB_WAITING;                   
533                         SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
534                                           periph_links.sle);
535                         periph->immediate_priority = CAM_PRIORITY_NONE;
536                         splx(s);
537                         wakeup(&periph->ccb_list);
538                 } else if (bp == NULL) {
539                         splx(s);
540                         xpt_release_ccb(start_ccb);
541                 } else {
542
543                         bufq_remove(&softc->buf_queue, bp);
544
545                         devstat_start_transaction(&softc->device_stats);
546
547                         /*
548                          * XXX JGibbs -
549                          * Interpret the contents of the bp as a CCB
550                          * and pass it to a routine shared by our ioctl
551                          * code and passtart.
552                          * For now, just biodone it with EIO so we don't
553                          * hang.
554                          */
555                         bp->b_error = EIO;
556                         bp->b_flags |= B_ERROR;
557                         bp->b_resid = bp->b_bcount;
558                         biodone(bp);
559                         bp = bufq_first(&softc->buf_queue);
560                         splx(s);
561   
562                         xpt_action(start_ccb);
563
564                 }
565                 if (bp != NULL) {
566                         /* Have more work to do, so ensure we stay scheduled */
567                         xpt_schedule(periph, /* XXX priority */1);
568                 }
569                 break;
570         }
571         }
572 }
573 static void
574 passdone(struct cam_periph *periph, union ccb *done_ccb)
575
576         struct pass_softc *softc;
577         struct ccb_scsiio *csio;
578
579         softc = (struct pass_softc *)periph->softc;
580         csio = &done_ccb->csio;
581         switch (csio->ccb_h.ccb_type) {
582         case PASS_CCB_BUFFER_IO:
583         {
584                 struct buf              *bp;
585                 cam_status              status;
586                 u_int8_t                scsi_status;
587                 devstat_trans_flags     ds_flags;
588
589                 status = done_ccb->ccb_h.status;
590                 scsi_status = done_ccb->csio.scsi_status;
591                 bp = (struct buf *)done_ccb->ccb_h.ccb_bp;
592                 /* XXX handle errors */
593                 if (!(((status & CAM_STATUS_MASK) == CAM_REQ_CMP)
594                   && (scsi_status == SCSI_STATUS_OK))) {
595                         int error;
596                         
597                         if ((error = passerror(done_ccb, 0, 0)) == ERESTART) {
598                                 /*
599                                  * A retry was scheuled, so
600                                  * just return.
601                                  */
602                                 return;
603                         }
604
605                         /*
606                          * XXX unfreeze the queue after we complete
607                          * the abort process
608                          */
609                         bp->b_error = error;
610                         bp->b_flags |= B_ERROR;
611                 }
612
613                 if ((done_ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_IN)
614                         ds_flags = DEVSTAT_READ;
615                 else if ((done_ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_OUT)
616                         ds_flags = DEVSTAT_WRITE;
617                 else
618                         ds_flags = DEVSTAT_NO_DATA;
619
620                 devstat_end_transaction_buf(&softc->device_stats, bp);
621                 biodone(bp);
622                 break;
623         }
624         case PASS_CCB_WAITING:
625         {
626                 /* Caller will release the CCB */
627                 wakeup(&done_ccb->ccb_h.cbfcnp);
628                 return;
629         }
630         }
631         xpt_release_ccb(done_ccb);
632 }
633
634 static int
635 passioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
636 {
637         struct  cam_periph *periph;
638         struct  pass_softc *softc;
639         u_int8_t unit;
640         int      error;
641
642
643         /* unit = dkunit(dev); */
644         /* XXX KDM fix this */
645         unit = minor(dev) & 0xff;
646
647         periph = cam_extend_get(passperiphs, unit);
648
649         if (periph == NULL)
650                 return(ENXIO);
651
652         softc = (struct pass_softc *)periph->softc;
653
654         error = 0;
655
656         switch (cmd) {
657
658         case CAMIOCOMMAND:
659         {
660                 union ccb *inccb;
661                 union ccb *ccb;
662                 int ccb_malloced;
663
664                 inccb = (union ccb *)addr;
665
666                 /*
667                  * Some CCB types, like scan bus and scan lun can only go
668                  * through the transport layer device.
669                  */
670                 if (inccb->ccb_h.func_code & XPT_FC_XPT_ONLY) {
671                         xpt_print_path(periph->path);
672                         printf("CCB function code %#x is restricted to the "
673                                "XPT device\n", inccb->ccb_h.func_code);
674                         error = ENODEV;
675                         break;
676                 }
677
678                 /*
679                  * Non-immediate CCBs need a CCB from the per-device pool
680                  * of CCBs, which is scheduled by the transport layer.
681                  * Immediate CCBs and user-supplied CCBs should just be
682                  * malloced.
683                  */
684                 if ((inccb->ccb_h.func_code & XPT_FC_QUEUED)
685                  && ((inccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0)) {
686                         ccb = cam_periph_getccb(periph,
687                                                 inccb->ccb_h.pinfo.priority);
688                         ccb_malloced = 0;
689                 } else {
690                         ccb = xpt_alloc_ccb();
691
692                         if (ccb != NULL)
693                                 xpt_setup_ccb(&ccb->ccb_h, periph->path,
694                                               inccb->ccb_h.pinfo.priority);
695                         ccb_malloced = 1;
696                 }
697
698                 if (ccb == NULL) {
699                         xpt_print_path(periph->path);
700                         printf("unable to allocate CCB\n");
701                         error = ENOMEM;
702                         break;
703                 }
704
705                 error = passsendccb(periph, ccb, inccb);
706
707                 if (ccb_malloced)
708                         xpt_free_ccb(ccb);
709                 else
710                         xpt_release_ccb(ccb);
711
712                 break;
713         }
714         default:
715                 error = cam_periph_ioctl(periph, cmd, addr, passerror);
716                 break;
717         }
718
719         return(error);
720 }
721
722 /*
723  * Generally, "ccb" should be the CCB supplied by the kernel.  "inccb"
724  * should be the CCB that is copied in from the user.
725  */
726 static int
727 passsendccb(struct cam_periph *periph, union ccb *ccb, union ccb *inccb)
728 {
729         struct pass_softc *softc;
730         struct cam_periph_map_info mapinfo;
731         int error, need_unmap;
732
733         softc = (struct pass_softc *)periph->softc;
734
735         need_unmap = 0;
736
737         /*
738          * There are some fields in the CCB header that need to be
739          * preserved, the rest we get from the user.
740          */
741         xpt_merge_ccb(ccb, inccb);
742
743         /*
744          * There's no way for the user to have a completion
745          * function, so we put our own completion function in here.
746          */
747         ccb->ccb_h.cbfcnp = passdone;
748
749         /*
750          * We only attempt to map the user memory into kernel space
751          * if they haven't passed in a physical memory pointer,
752          * and if there is actually an I/O operation to perform.
753          * Right now cam_periph_mapmem() only supports SCSI and device
754          * match CCBs.  For the SCSI CCBs, we only pass the CCB in if
755          * there's actually data to map.  cam_periph_mapmem() will do the
756          * right thing, even if there isn't data to map, but since CCBs
757          * without data are a reasonably common occurance (e.g. test unit
758          * ready), it will save a few cycles if we check for it here.
759          */
760         if (((ccb->ccb_h.flags & CAM_DATA_PHYS) == 0)
761          && (((ccb->ccb_h.func_code == XPT_SCSI_IO)
762             && ((ccb->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_NONE))
763           || (ccb->ccb_h.func_code == XPT_DEV_MATCH))) {
764
765                 bzero(&mapinfo, sizeof(mapinfo));
766
767                 error = cam_periph_mapmem(ccb, &mapinfo); 
768
769                 /*
770                  * cam_periph_mapmem returned an error, we can't continue.
771                  * Return the error to the user.
772                  */
773                 if (error)
774                         return(error);
775
776                 /*
777                  * We successfully mapped the memory in, so we need to
778                  * unmap it when the transaction is done.
779                  */
780                 need_unmap = 1;
781         }
782
783         /*
784          * If the user wants us to perform any error recovery, then honor
785          * that request.  Otherwise, it's up to the user to perform any
786          * error recovery.
787          */
788         error = cam_periph_runccb(ccb,
789                                   (ccb->ccb_h.flags & CAM_PASS_ERR_RECOVER) ?
790                                   passerror : NULL,
791                                   /* cam_flags */ 0,
792                                   /* sense_flags */SF_RETRY_UA | SF_RETRY_SELTO,
793                                   &softc->device_stats);
794
795         if (need_unmap != 0)
796                 cam_periph_unmapmem(ccb, &mapinfo);
797
798         ccb->ccb_h.cbfcnp = NULL;
799         ccb->ccb_h.periph_priv = inccb->ccb_h.periph_priv;
800         bcopy(ccb, inccb, sizeof(union ccb));
801
802         return(error);
803 }
804
805 static int
806 passerror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
807 {
808         struct cam_periph *periph;
809         struct pass_softc *softc;
810
811         periph = xpt_path_periph(ccb->ccb_h.path);
812         softc = (struct pass_softc *)periph->softc;
813         
814         return(cam_periph_error(ccb, cam_flags, sense_flags, 
815                                  &softc->saved_ccb));
816 }