/*
 * $FreeBSD: src/sys/cam/scsi/scsi_sa.c,v 1.45.2.13 2002/12/17 17:08:50 trhodes Exp $
 *
 * Implementation of SCSI Sequential Access Peripheral driver for CAM.
 *
 * Copyright (c) 1999, 2000 Matthew Jacob
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <sys/queue.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/kernel.h>
#endif
#include <sys/types.h>
#ifdef _KERNEL
#include <sys/buf.h>
#include <sys/malloc.h>
#endif
#include <sys/mtio.h>
#include <sys/conf.h>
#ifdef _KERNEL
#include <sys/proc.h>
#include <sys/buf2.h>
#endif
#include <sys/caps.h>
#include <sys/fcntl.h>
#include <sys/devicestat.h>
#include <machine/limits.h>

#ifndef _KERNEL
#include <stdio.h>
#include <string.h>
#endif

#include "../cam.h"
#include "../cam_ccb.h"
#include "../cam_extend.h"
#include "../cam_periph.h"
#include "../cam_xpt_periph.h"
#include "../cam_debug.h"

#include "scsi_all.h"
#include "scsi_message.h"
#include "scsi_sa.h"

#ifdef _KERNEL

#include <opt_sa.h>

#ifndef SA_IO_TIMEOUT
#define SA_IO_TIMEOUT           4
#endif
#ifndef SA_SPACE_TIMEOUT
#define SA_SPACE_TIMEOUT        1 * 60
#endif
#ifndef SA_REWIND_TIMEOUT
#define SA_REWIND_TIMEOUT       2 * 60
#endif
#ifndef SA_ERASE_TIMEOUT
#define SA_ERASE_TIMEOUT        4 * 60
#endif

#define SCSIOP_TIMEOUT          (60 * 1000)     /* not an option */

#define IO_TIMEOUT              (SA_IO_TIMEOUT * 60 * 1000)
#define REWIND_TIMEOUT          (SA_REWIND_TIMEOUT * 60 * 1000)
#define ERASE_TIMEOUT           (SA_ERASE_TIMEOUT * 60 * 1000)
#define SPACE_TIMEOUT           (SA_SPACE_TIMEOUT * 60 * 1000)

/*
 * Additional options that can be set for config: SA_1FM_AT_EOT
 */

#define QFRLS(ccb)      \
        if (((ccb)->ccb_h.status & CAM_DEV_QFRZN) != 0) \
                cam_release_devq((ccb)->ccb_h.path, 0, 0, 0, FALSE)

/*
 * Driver states
 */

MALLOC_DEFINE(M_SCSISA, "SCSI sa", "SCSI sequential access buffers");

typedef enum {
        SA_STATE_NORMAL, SA_STATE_ABNORMAL
} sa_state;

#define ccb_pflags      ppriv_field0
#define ccb_bio         ppriv_ptr1

#define SA_CCB_POLLED           0x00
#define SA_CCB_BUFFER_IO        0x01
#define SA_CCB_WAITING          0x02
#define SA_CCB_TYPEMASK         0x0F
#define SA_POSITION_UPDATED     0x10

#define Set_CCB_Type(x, type) do {                      \
        x->ccb_h.ccb_pflags &= ~SA_CCB_TYPEMASK;        \
        x->ccb_h.ccb_pflags |= type;                    \
    } while (0)

#define CCB_Type(x)     (x->ccb_h.ccb_pflags & SA_CCB_TYPEMASK)



typedef enum {
        SA_FLAG_OPEN            = 0x0001,
        SA_FLAG_FIXED           = 0x0002,
        SA_FLAG_TAPE_LOCKED     = 0x0004,
        SA_FLAG_TAPE_MOUNTED    = 0x0008,
        SA_FLAG_TAPE_WP         = 0x0010,
        SA_FLAG_TAPE_WRITTEN    = 0x0020,
        SA_FLAG_EOM_PENDING     = 0x0040,
        SA_FLAG_EIO_PENDING     = 0x0080,
        SA_FLAG_EOF_PENDING     = 0x0100,
        SA_FLAG_ERR_PENDING     = (SA_FLAG_EOM_PENDING|SA_FLAG_EIO_PENDING|
                                   SA_FLAG_EOF_PENDING),
        SA_FLAG_INVALID         = 0x0200,
        SA_FLAG_COMP_ENABLED    = 0x0400,
        SA_FLAG_COMP_SUPP       = 0x0800,
        SA_FLAG_COMP_UNSUPP     = 0x1000,
        SA_FLAG_TAPE_FROZEN     = 0x2000
} sa_flags;

typedef enum {
        SA_MODE_REWIND          = 0x00,
        SA_MODE_NOREWIND        = 0x01,
        SA_MODE_OFFLINE         = 0x02
} sa_mode;

typedef enum {
        SA_PARAM_NONE           = 0x00,
        SA_PARAM_BLOCKSIZE      = 0x01,
        SA_PARAM_DENSITY        = 0x02,
        SA_PARAM_COMPRESSION    = 0x04,
        SA_PARAM_BUFF_MODE      = 0x08,
        SA_PARAM_NUMBLOCKS      = 0x10,
        SA_PARAM_WP             = 0x20,
        SA_PARAM_SPEED          = 0x40,
        SA_PARAM_ALL            = 0x7f
} sa_params;

typedef enum {
        SA_QUIRK_NONE           = 0x00,
        SA_QUIRK_NOCOMP         = 0x01, /* Can't deal with compression at all */
        SA_QUIRK_FIXED          = 0x02, /* Force fixed mode */
        SA_QUIRK_VARIABLE       = 0x04, /* Force variable mode */
        SA_QUIRK_2FM            = 0x08, /* Needs Two File Marks at EOD */
        SA_QUIRK_1FM            = 0x10, /* No more than 1 File Mark at EOD */
        SA_QUIRK_NODREAD        = 0x20, /* Don't try and dummy read density */
        SA_QUIRK_NO_MODESEL     = 0x40, /* Don't do mode select at all */
        SA_QUIRK_NO_CPAGE       = 0x80  /* Don't use DEVICE COMPRESSION page */
} sa_quirks;

/* units are bits 4-7, 16-21 (1024 units) */
#define SAUNIT(DEV) \
        (((minor(DEV) & 0xF0) >> 4) |  ((minor(DEV) & 0x3f0000) >> 16))

#define SAMODE(z) ((minor(z) & 0x3))
#define SADENSITY(z) (((minor(z) >> 2) & 0x3))
#define SA_IS_CTRL(z) (minor(z) & (1 << 29))

#define SA_NOT_CTLDEV   0
#define SA_CTLDEV       1

#define SA_ATYPE_R      0
#define SA_ATYPE_NR     1
#define SA_ATYPE_ER     2

#define SAMINOR(ctl, unit, mode, access) \
        ((ctl << 29) | ((unit & 0x3f0) << 16) | ((unit & 0xf) << 4) | \
        (mode << 0x2) | (access & 0x3))

#define SA_UNITMASK     SAMINOR(0, -1, 0, 0)
#define SA_UNIT(unit)   SAMINOR(0, unit, 0, 0)

#define SA_NUM_MODES    4

struct sa_softc {
        sa_state        state;
        sa_flags        flags;
        sa_quirks       quirks;
        struct          bio_queue_head bio_queue;
        int             queue_count;
        struct          devstat device_stats;
        int             blk_gran;
        int             blk_mask;
        int             blk_shift;
        u_int32_t       max_blk;
        u_int32_t       min_blk;
        u_int32_t       comp_algorithm;
        u_int32_t       saved_comp_algorithm;
        u_int32_t       media_blksize;
        u_int32_t       last_media_blksize;
        u_int32_t       media_numblks;
        u_int8_t        media_density;
        u_int8_t        speed;
        u_int8_t        scsi_rev;
        u_int8_t        dsreg;          /* mtio mt_dsreg, redux */
        int             buffer_mode;
        int             filemarks;
        union           ccb saved_ccb;
        int             last_resid_was_io;

        /*
         * Relative to BOT Location.
         */
        daddr_t         fileno;
        daddr_t         blkno;

        /*
         * Latched Error Info
         */
        struct {
                struct scsi_sense_data _last_io_sense;
                u_int32_t _last_io_resid;
                u_int8_t _last_io_cdb[CAM_MAX_CDBLEN];
                struct scsi_sense_data _last_ctl_sense;
                u_int32_t _last_ctl_resid;
                u_int8_t _last_ctl_cdb[CAM_MAX_CDBLEN];
#define last_io_sense   errinfo._last_io_sense
#define last_io_resid   errinfo._last_io_resid
#define last_io_cdb     errinfo._last_io_cdb
#define last_ctl_sense  errinfo._last_ctl_sense
#define last_ctl_resid  errinfo._last_ctl_resid
#define last_ctl_cdb    errinfo._last_ctl_cdb
        } errinfo;
        /*
         * Misc other flags/state
         */
        u_int32_t
                                        : 29,
                open_rdonly             : 1,    /* open read-only */
                open_pending_mount      : 1,    /* open pending mount */
                ctrl_mode               : 1;    /* control device open */
};

struct sa_quirk_entry {
        struct scsi_inquiry_pattern inq_pat;    /* matching pattern */
        sa_quirks quirks;       /* specific quirk type */
        u_int32_t prefblk;      /* preferred blocksize when in fixed mode */
};

static struct sa_quirk_entry sa_quirk_table[] =
{
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "OnStream",
                  "ADR*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_NODREAD |
                   SA_QUIRK_1FM|SA_QUIRK_NO_MODESEL, 32768
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "Python 06408*", "*"}, SA_QUIRK_NODREAD, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "Python 25601*", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_NODREAD, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "Python*", "*"}, SA_QUIRK_NODREAD, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "VIPER 150*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "VIPER 2525 25462", "-011"},
                  SA_QUIRK_NOCOMP|SA_QUIRK_1FM|SA_QUIRK_NODREAD, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "ARCHIVE",
                  "VIPER 2525*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 1024
        },
#if     0
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
                  "C15*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_NO_CPAGE, 0,
        },
#endif
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
                  "C56*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
                  "T20*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
                  "T4000*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "HP",
                  "HP-88780*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "KENNEDY",
                  "*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "M4 DATA",
                  "123107 SCSI*", "*"}, SA_QUIRK_VARIABLE|SA_QUIRK_2FM, 0
        },
        {       /* jreynold@primenet.com */
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "Seagate",
                "STT8000N*", "*"}, SA_QUIRK_1FM, 0
        },
        {       /* mike@sentex.net */
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "Seagate",
                "STT20000*", "*"}, SA_QUIRK_1FM, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " TDC 3600", "U07:"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " TDC 3800", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " TDC 4100", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " TDC 4200", "*"}, SA_QUIRK_NOCOMP|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " SLR*", "*"}, SA_QUIRK_1FM, 0
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "WANGTEK",
                  "5525ES*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 512
        },
        {
                { T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "WANGTEK",
                  "51000*", "*"}, SA_QUIRK_FIXED|SA_QUIRK_1FM, 1024
        }
};

static  d_open_t        saopen;
static  d_close_t       saclose;
static  d_strategy_t    sastrategy;
static  d_ioctl_t       saioctl;
static  periph_init_t   sainit;
static  periph_ctor_t   saregister;
static  periph_oninv_t  saoninvalidate;
static  periph_dtor_t   sacleanup;
static  periph_start_t  sastart;
static  void            saasync(void *callback_arg, u_int32_t code,
                                struct cam_path *path, void *arg);
static  void            sadone(struct cam_periph *periph,
                               union ccb *start_ccb);
static  int             saerror(union ccb *ccb, u_int32_t cam_flags,
                                u_int32_t sense_flags);
static int              samarkswanted(struct cam_periph *);
static int              sacheckeod(struct cam_periph *periph);
static int              sagetparams(struct cam_periph *periph,
                                    sa_params params_to_get,
                                    u_int32_t *blocksize, u_int8_t *density,
                                    u_int32_t *numblocks, int *buff_mode,
                                    u_int8_t *write_protect, u_int8_t *speed,
                                    int *comp_supported, int *comp_enabled,
                                    u_int32_t *comp_algorithm,
                                    sa_comp_t *comp_page);
static int              sasetparams(struct cam_periph *periph,
                                    sa_params params_to_set,
                                    u_int32_t blocksize, u_int8_t density,
                                    u_int32_t comp_algorithm,
                                    u_int32_t sense_flags);
static void             saprevent(struct cam_periph *periph, int action);
static int              sarewind(struct cam_periph *periph);
static int              saspace(struct cam_periph *periph, int count,
                                scsi_space_code code);
static int              samount(struct cam_periph *, int, cdev_t);
static int              saretension(struct cam_periph *periph);
static int              sareservereleaseunit(struct cam_periph *periph,
                                             int reserve);
static int              saloadunload(struct cam_periph *periph, int load);
static int              saerase(struct cam_periph *periph, int longerase);
static int              sawritefilemarks(struct cam_periph *periph,
                                         int nmarks, int setmarks);
static int              sardpos(struct cam_periph *periph, int, u_int32_t *);
static int              sasetpos(struct cam_periph *periph, int, u_int32_t *);


static struct periph_driver sadriver =
{
        sainit, "sa",
        TAILQ_HEAD_INITIALIZER(sadriver.units), /* generation */ 0
};

PERIPHDRIVER_DECLARE(sa, sadriver);

/* For 2.2-stable support */
#ifndef D_TAPE
#define D_TAPE 0
#endif

static struct dev_ops sa_ops = {
        { "sa", 0, D_TAPE },
        .d_open =       saopen,
        .d_close =      saclose,
        .d_read =       physread,
        .d_write =      physwrite,
        .d_ioctl =      saioctl,
        .d_strategy =   sastrategy,
};

static struct extend_array *saperiphs;

static int
saopen(struct dev_open_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct cam_periph *periph;
        struct sa_softc *softc;
        int unit;
        int error;

        /*
         * Disallow CAM access if RESTRICTEDROOT
         */
        if (caps_priv_check_self(SYSCAP_RESTRICTEDROOT))
                return (EPERM);

        unit = SAUNIT(dev);

        periph = cam_extend_get(saperiphs, unit);
        if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
                return (ENXIO);
        }

        cam_periph_lock(periph);

        softc = (struct sa_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE|CAM_DEBUG_INFO,
            ("saopen(%d): dev=0x%x softc=0x%x\n", unit, unit, softc->flags));

        if (SA_IS_CTRL(dev)) {
                softc->ctrl_mode = 1;
                cam_periph_unlock(periph);
                return (0);
        }

        if ((error = cam_periph_hold(periph, PCATCH)) != 0) {
                cam_periph_unlock(periph);
                cam_periph_release(periph);
                return (error);
        }

        if (softc->flags & SA_FLAG_OPEN) {
                error = EBUSY;
        } else if (softc->flags & SA_FLAG_INVALID) {
                error = ENXIO;
        } else {
                /*
                 * Preserve whether this is a read_only open.
                 */
                softc->open_rdonly = (ap->a_oflags & O_RDWR) == O_RDONLY;

                /*
                 * The function samount ensures media is loaded and ready.
                 * It also does a device RESERVE if the tape isn't yet mounted.
                 *
                 * If the mount fails and this was a non-blocking open,
                 * make this a 'open_pending_mount' action.
                 */
                error = samount(periph, ap->a_oflags, dev);
                if (error && (ap->a_oflags & O_NONBLOCK)) {
                        softc->flags |= SA_FLAG_OPEN;
                        softc->open_pending_mount = 1;
                        cam_periph_unhold(periph, 1);
                        return (0);
                }
        }

        if (error) {
                cam_periph_unhold(periph, 1);
                cam_periph_release(periph);
                return (error);
        }

        saprevent(periph, PR_PREVENT);
        softc->flags |= SA_FLAG_OPEN;

        cam_periph_unhold(periph, 1);
        return (error);
}

static int
saclose(struct dev_close_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct  cam_periph *periph;
        struct  sa_softc *softc;
        int     unit, mode, error, writing, tmp;
        int     closedbits = SA_FLAG_OPEN;

        unit = SAUNIT(dev);
        mode = SAMODE(dev);
        periph = cam_extend_get(saperiphs, unit);
        if (periph == NULL)
                return (ENXIO); 

        cam_periph_lock(periph);

        softc = (struct sa_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE|CAM_DEBUG_INFO,
            ("saclose(%d): dev=0x%x softc=0x%x\n", unit, unit, softc->flags));


        softc->open_rdonly = 0; 
        if (SA_IS_CTRL(dev)) {
                softc->ctrl_mode = 0;
                cam_periph_unlock(periph);
                cam_periph_release(periph);
                return (0);
        }

        if (softc->open_pending_mount) {
                softc->flags &= ~SA_FLAG_OPEN;
                softc->open_pending_mount = 0; 
                cam_periph_unlock(periph);
                cam_periph_release(periph);
                return (0);
        }

        if ((error = cam_periph_hold(periph, 0)) != 0) {
                cam_periph_unlock(periph);
                return (error);
        }

        /*
         * Were we writing the tape?
         */
        writing = (softc->flags & SA_FLAG_TAPE_WRITTEN) != 0;

        /*
         * See whether or not we need to write filemarks. If this
         * fails, we probably have to assume we've lost tape
         * position.
         */
        error = sacheckeod(periph);
        if (error) {
                xpt_print(periph->path,
                    "failed to write terminating filemark(s)\n");
                softc->flags |= SA_FLAG_TAPE_FROZEN;
        }

        /*
         * Whatever we end up doing, allow users to eject tapes from here on.
         */
        saprevent(periph, PR_ALLOW);

        /*
         * Decide how to end...
         */
        if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0) {
                closedbits |= SA_FLAG_TAPE_FROZEN;
        } else switch (mode) {
        case SA_MODE_OFFLINE:
                /*
                 * An 'offline' close is an unconditional release of
                 * frozen && mount conditions, irrespective of whether
                 * these operations succeeded. The reason for this is
                 * to allow at least some kind of programmatic way
                 * around our state getting all fouled up. If somebody
                 * issues an 'offline' command, that will be allowed
                 * to clear state.
                 */
                sarewind(periph);
                saloadunload(periph, FALSE);
                closedbits |= SA_FLAG_TAPE_MOUNTED|SA_FLAG_TAPE_FROZEN;
                break;
        case SA_MODE_REWIND:
                /*
                 * If the rewind fails, return an error- if anyone cares,
                 * but not overwriting any previous error.
                 *
                 * We don't clear the notion of mounted here, but we do
                 * clear the notion of frozen if we successfully rewound.
                 */
                tmp = sarewind(periph);
                if (tmp) {
                        if (error != 0)
                                error = tmp;
                } else {
                        closedbits |= SA_FLAG_TAPE_FROZEN;
                }
                break;
        case SA_MODE_NOREWIND:
                /*
                 * If we're not rewinding/unloading the tape, find out
                 * whether we need to back up over one of two filemarks
                 * we wrote (if we wrote two filemarks) so that appends
                 * from this point on will be sane.
                 */
                if (error == 0 && writing && (softc->quirks & SA_QUIRK_2FM)) {
                        tmp = saspace(periph, -1, SS_FILEMARKS);
                        if (tmp) {
                                xpt_print(periph->path, "unable to backspace "
                                    "over one of double filemarks at end of "
                                    "tape\n");
                                xpt_print(periph->path, "it is possible that "
                                    "this device needs a SA_QUIRK_1FM quirk set"
                                    "for it\n");
                                softc->flags |= SA_FLAG_TAPE_FROZEN;
                        }
                }
                break;
        default:
                xpt_print(periph->path, "unknown mode 0x%x in saclose\n", mode);
                /* NOTREACHED */
                break;
        }

        /*
         * We wish to note here that there are no more filemarks to be written.
         */
        softc->filemarks = 0;
        softc->flags &= ~SA_FLAG_TAPE_WRITTEN;

        /*
         * And we are no longer open for business.
         */
        softc->flags &= ~closedbits;

        /*
         * Inform users if tape state if frozen....
         */
        if (softc->flags & SA_FLAG_TAPE_FROZEN) {
                xpt_print(periph->path, "tape is now frozen- use an OFFLINE, "
                    "REWIND or MTEOM command to clear this state.\n");
        }
        
        /* release the device if it is no longer mounted */
        if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0)
                sareservereleaseunit(periph, FALSE);

        cam_periph_unhold(periph, 1);
        cam_periph_release(periph);

        return (error); 
}

/*
 * Actually translate the requested transfer into one the physical driver
 * can understand.  The transfer is described by a buf and will include
 * only one physical transfer.
 */
static int
sastrategy(struct dev_strategy_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct bio *bio = ap->a_bio;
        struct buf *bp = bio->bio_buf;
        struct cam_periph *periph;
        struct sa_softc *softc;
        u_int  unit;
        
        if (SA_IS_CTRL(dev)) {
                bp->b_error = EINVAL;
                goto bad;
        }
        unit = SAUNIT(dev);
        periph = cam_extend_get(saperiphs, unit);
        if (periph == NULL) {
                bp->b_error = ENXIO;
                goto bad;
        }
        cam_periph_lock(periph);

        softc = (struct sa_softc *)periph->softc;

        if (softc->flags & SA_FLAG_INVALID) {
                cam_periph_unlock(periph);
                bp->b_error = ENXIO;
                goto bad;
        }

        if (softc->flags & SA_FLAG_TAPE_FROZEN) {
                cam_periph_unlock(periph);
                bp->b_error = EPERM;
                goto bad;
        }

        /*
         * This should actually never occur as the write(2)
         * system call traps attempts to write to a read-only
         * file descriptor.
         */
        if (bp->b_cmd == BUF_CMD_WRITE && softc->open_rdonly) {
                cam_periph_unlock(periph);
                bp->b_error = EBADF;
                goto bad;
        }

        if (softc->open_pending_mount) {
                int error = samount(periph, 0, dev);
                if (error) {
                        cam_periph_unlock(periph);
                        bp->b_error = ENXIO;
                        goto bad;
                }
                saprevent(periph, PR_PREVENT);
                softc->open_pending_mount = 0;
        }

        /*
         * If it's a null transfer, return immediately
         */
        if (bp->b_bcount == 0) {
                cam_periph_unlock(periph);
                goto done;
        }

        /* valid request?  */
        if (softc->flags & SA_FLAG_FIXED) {
                /*
                 * Fixed block device.  The byte count must
                 * be a multiple of our block size.
                 */
                if (((softc->blk_mask != ~0) &&
                    ((bp->b_bcount & softc->blk_mask) != 0)) ||
                    ((softc->blk_mask == ~0) &&
                    ((bp->b_bcount % softc->min_blk) != 0))) {
                        xpt_print(periph->path, "Invalid request.  Fixed block "
                            "device requests must be a multiple of %d bytes\n",
                            softc->min_blk);
                        cam_periph_unlock(periph);
                        bp->b_error = EINVAL;
                        goto bad;
                }
        } else if ((bp->b_bcount > softc->max_blk) ||
                   (bp->b_bcount < softc->min_blk) ||
                   (bp->b_bcount & softc->blk_mask) != 0) {

                xpt_print_path(periph->path);
                kprintf("Invalid request.  Variable block "
                    "device requests must be ");
                if (softc->blk_mask != 0) {
                        kprintf("a multiple of %d ", (0x1 << softc->blk_gran));
                }
                kprintf("between %d and %d bytes\n", softc->min_blk,
                    softc->max_blk);
                cam_periph_unlock(periph);
                bp->b_error = EINVAL;
                goto bad;
        }
        
        /*
         * Place it at the end of the queue.
         */
        bioq_insert_tail(&softc->bio_queue, bio);
        softc->queue_count++;
#if     0
        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
            ("sastrategy: queuing a %ld %s byte %s\n", bp->bio_bcount,
            (softc->flags & SA_FLAG_FIXED)?  "fixed" : "variable",
            (bp->bio_cmd == BIO_READ)? "read" : "write"));
#endif
        if (softc->queue_count > 1) {
                CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                    ("sastrategy: queue count now %d\n", softc->queue_count));
        }
        
        /*
         * Schedule ourselves for performing the work.
         */
        xpt_schedule(periph, 1);
        cam_periph_unlock(periph);

        return(0);
bad:
        bp->b_flags |= B_ERROR;
done:

        /*
         * Correctly set the buf to indicate a completed xfer
         */
        bp->b_resid = bp->b_bcount;
        biodone(bio);
        return(0);
}


#define PENDING_MOUNT_CHECK(softc, periph, dev)         \
        if (softc->open_pending_mount) {                \
                error = samount(periph, 0, dev);        \
                if (error) {                            \
                        break;                          \
                }                                       \
                saprevent(periph, PR_PREVENT);          \
                softc->open_pending_mount = 0;          \
        }

static int
saioctl(struct dev_ioctl_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        caddr_t addr = ap->a_data;
        struct cam_periph *periph;
        struct sa_softc *softc;
        scsi_space_code spaceop;
        int didholdperiph = 0;
        int unit;
        int mode;
        int error = 0;

        unit = SAUNIT(dev);
        mode = SAMODE(dev);
        error = 0;              /* shut up gcc */
        spaceop = 0;            /* shut up gcc */

        periph = cam_extend_get(saperiphs, unit);
        if (periph == NULL)
                return (ENXIO); 

        cam_periph_lock(periph);
        softc = (struct sa_softc *)periph->softc;

        /*
         * Check for control mode accesses. We allow MTIOCGET and
         * MTIOCERRSTAT (but need to be the only one open in order
         * to clear latched status), and MTSETBSIZE, MTSETDNSTY
         * and MTCOMP (but need to be the only one accessing this
         * device to run those).
         */

        if (SA_IS_CTRL(dev)) {
                switch (ap->a_cmd) {
                case MTIOCGETEOTMODEL:
                case MTIOCGET:
                        break;
                case MTIOCERRSTAT:
                        /*
                         * If the periph isn't already locked, lock it
                         * so our MTIOCERRSTAT can reset latched error stats.
                         *
                         * If the periph is already locked, skip it because
                         * we're just getting status and it'll be up to the
                         * other thread that has this device open to do
                         * an MTIOCERRSTAT that would clear latched status.
                         */
                        if ((periph->flags & CAM_PERIPH_LOCKED) == 0) {
                                error = cam_periph_hold(periph, PCATCH);
                                if (error != 0) {
                                        return (error);
                                }
                                didholdperiph = 1;
                        }
                        break;

                case MTIOCTOP:
                {
                        struct mtop *mt = (struct mtop *) addr;

                        /*
                         * Check to make sure it's an OP we can perform
                         * with no media inserted.
                         */
                        switch (mt->mt_op) {
                        case MTSETBSIZ:
                        case MTSETDNSTY:
                        case MTCOMP:
                                mt = NULL;
                                /* FALLTHROUGH */
                        default:
                                break;
                        }
                        if (mt != NULL) {
                                break;
                        }
                        /* FALLTHROUGH */
                }
                case MTIOCSETEOTMODEL:
                        /*
                         * We need to acquire the peripheral here rather
                         * than at open time because we are sharing writable
                         * access to data structures.
                         */
                        error = cam_periph_hold(periph, PCATCH);
                        if (error != 0) {
                                return (error);
                        }
                        didholdperiph = 1;
                        break;

                default:
                        return (EINVAL);
                }
        }

        /*
         * Find the device that the user is talking about
         */
        switch (ap->a_cmd) {
        case MTIOCGET:
        {
                struct mtget *g = (struct mtget *)addr;

                /*
                 * If this isn't the control mode device, actually go out
                 * and ask the drive again what it's set to.
                 */
                if (!SA_IS_CTRL(dev) && !softc->open_pending_mount) {
                        u_int8_t write_protect = 0;     /* silence gcc */
                        int comp_enabled = 0;           /* silence gcc */
                        int comp_supported = 0;         /* silence gcc */

                        error = sagetparams(periph, SA_PARAM_ALL,
                            &softc->media_blksize, &softc->media_density,
                            &softc->media_numblks, &softc->buffer_mode,
                            &write_protect, &softc->speed, &comp_supported,
                            &comp_enabled, &softc->comp_algorithm, NULL);
                        if (error)
                                break;
                        if (write_protect)
                                softc->flags |= SA_FLAG_TAPE_WP;
                        else
                                softc->flags &= ~SA_FLAG_TAPE_WP;
                        softc->flags &= ~(SA_FLAG_COMP_SUPP|
                            SA_FLAG_COMP_ENABLED|SA_FLAG_COMP_UNSUPP);
                        if (comp_supported) {
                                if (softc->saved_comp_algorithm == 0)
                                        softc->saved_comp_algorithm =
                                            softc->comp_algorithm;
                                softc->flags |= SA_FLAG_COMP_SUPP;
                                if (comp_enabled)
                                        softc->flags |= SA_FLAG_COMP_ENABLED;
                        } else  
                                softc->flags |= SA_FLAG_COMP_UNSUPP;
                }
                bzero(g, sizeof(struct mtget));
                g->mt_type = MT_ISAR;
                if (softc->flags & SA_FLAG_COMP_UNSUPP) {
                        g->mt_comp = MT_COMP_UNSUPP;
                        g->mt_comp0 = MT_COMP_UNSUPP;
                        g->mt_comp1 = MT_COMP_UNSUPP;
                        g->mt_comp2 = MT_COMP_UNSUPP;
                        g->mt_comp3 = MT_COMP_UNSUPP;
                } else {
                        if ((softc->flags & SA_FLAG_COMP_ENABLED) == 0) {
                                g->mt_comp = MT_COMP_DISABLED;
                        } else {
                                g->mt_comp = softc->comp_algorithm;
                        }
                        g->mt_comp0 = softc->comp_algorithm;
                        g->mt_comp1 = softc->comp_algorithm;
                        g->mt_comp2 = softc->comp_algorithm;
                        g->mt_comp3 = softc->comp_algorithm;
                }
                g->mt_density = softc->media_density;
                g->mt_density0 = softc->media_density;
                g->mt_density1 = softc->media_density;
                g->mt_density2 = softc->media_density;
                g->mt_density3 = softc->media_density;
                g->mt_blksiz = softc->media_blksize;
                g->mt_blksiz0 = softc->media_blksize;
                g->mt_blksiz1 = softc->media_blksize;
                g->mt_blksiz2 = softc->media_blksize;
                g->mt_blksiz3 = softc->media_blksize;
                g->mt_fileno = softc->fileno;
                g->mt_blkno = softc->blkno;
                g->mt_dsreg = (short) softc->dsreg;
                /*
                 * Yes, we know that this is likely to overflow
                 */
                if (softc->last_resid_was_io) {
                        if ((g->mt_resid = (short) softc->last_io_resid) != 0) {
                                if (SA_IS_CTRL(dev) == 0 || didholdperiph) {
                                        softc->last_io_resid = 0;
                                }
                        }
                } else {
                        if ((g->mt_resid = (short)softc->last_ctl_resid) != 0) {
                                if (SA_IS_CTRL(dev) == 0 || didholdperiph) {
                                        softc->last_ctl_resid = 0;
                                }
                        }
                }
                error = 0;
                break;
        }
        case MTIOCERRSTAT:
        {
                struct scsi_tape_errors *sep =
                    &((union mterrstat *)addr)->scsi_errstat;

                CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
                    ("saioctl: MTIOCERRSTAT\n"));

                bzero(sep, sizeof(*sep));
                sep->io_resid = softc->last_io_resid;
                bcopy((caddr_t) &softc->last_io_sense, sep->io_sense,
                    sizeof (sep->io_sense));
                bcopy((caddr_t) &softc->last_io_cdb, sep->io_cdb,
                    sizeof (sep->io_cdb));
                sep->ctl_resid = softc->last_ctl_resid;
                bcopy((caddr_t) &softc->last_ctl_sense, sep->ctl_sense,
                    sizeof (sep->ctl_sense));
                bcopy((caddr_t) &softc->last_ctl_cdb, sep->ctl_cdb,
                    sizeof (sep->ctl_cdb));

                if ((SA_IS_CTRL(dev) == 0 && softc->open_pending_mount) ||
                    didholdperiph)
                        bzero((caddr_t) &softc->errinfo,
                            sizeof (softc->errinfo));
                error = 0;
                break;
        }
        case MTIOCTOP:
        {
                struct mtop *mt;
                int    count;

                PENDING_MOUNT_CHECK(softc, periph, dev);

                mt = (struct mtop *)addr;

                CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
                         ("saioctl: op=0x%x count=0x%x\n",
                          mt->mt_op, mt->mt_count));

                count = mt->mt_count;
                switch (mt->mt_op) {
                case MTWEOF:    /* write an end-of-file marker */
                        /*
                         * We don't need to clear the SA_FLAG_TAPE_WRITTEN
                         * flag because by keeping track of filemarks
                         * we have last written we know ehether or not
                         * we need to write more when we close the device.
                         */
                        error = sawritefilemarks(periph, count, FALSE);
                        break;
                case MTWSS:     /* write a setmark */
                        error = sawritefilemarks(periph, count, TRUE);
                        break;
                case MTBSR:     /* backward space record */
                case MTFSR:     /* forward space record */
                case MTBSF:     /* backward space file */
                case MTFSF:     /* forward space file */
                case MTBSS:     /* backward space setmark */
                case MTFSS:     /* forward space setmark */
                case MTEOD:     /* space to end of recorded medium */
                {
                        int nmarks;

                        spaceop = SS_FILEMARKS;
                        nmarks = softc->filemarks;
                        error = sacheckeod(periph);
                        if (error) {
                                xpt_print(periph->path,
                                    "EOD check prior to spacing failed\n");
                                softc->flags |= SA_FLAG_EIO_PENDING;
                                break;
                        }
                        nmarks -= softc->filemarks;
                        switch(mt->mt_op) {
                        case MTBSR:
                                count = -count;
                                /* FALLTHROUGH */
                        case MTFSR:
                                spaceop = SS_BLOCKS;
                                break;
                        case MTBSF:
                                count = -count;
                                /* FALLTHROUGH */
                        case MTFSF:
                                break;
                        case MTBSS:
                                count = -count;
                                /* FALLTHROUGH */
                        case MTFSS:
                                spaceop = SS_SETMARKS;
                                break;
                        case MTEOD:
                                spaceop = SS_EOD;
                                count = 0;
                                nmarks = 0;
                                break;
                        default:
                                error = EINVAL;
                                break;
                        }
                        if (error)
                                break;

                        nmarks = softc->filemarks;
                        /*
                         * XXX: Why are we checking again?
                         */
                        error = sacheckeod(periph);
                        if (error)
                                break;
                        nmarks -= softc->filemarks;
                        error = saspace(periph, count - nmarks, spaceop);
                        /*
                         * At this point, clear that we've written the tape
                         * and that we've written any filemarks. We really
                         * don't know what the applications wishes to do next-
                         * the sacheckeod's will make sure we terminated the
                         * tape correctly if we'd been writing, but the next
                         * action the user application takes will set again
                         * whether we need to write filemarks.
                         */
                        softc->flags &=
                            ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
                        softc->filemarks = 0;
                        break;
                }
                case MTREW:     /* rewind */
                        PENDING_MOUNT_CHECK(softc, periph, dev);
                        sacheckeod(periph);
                        error = sarewind(periph);
                        /* see above */
                        softc->flags &=
                            ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
                        softc->flags &= ~SA_FLAG_ERR_PENDING;
                        softc->filemarks = 0;
                        break;
                case MTERASE:   /* erase */
                        PENDING_MOUNT_CHECK(softc, periph, dev);
                        error = saerase(periph, count);
                        softc->flags &=
                            ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
                        softc->flags &= ~SA_FLAG_ERR_PENDING;
                        break;
                case MTRETENS:  /* re-tension tape */
                        PENDING_MOUNT_CHECK(softc, periph, dev);
                        error = saretension(periph);            
                        softc->flags &=
                            ~(SA_FLAG_TAPE_WRITTEN|SA_FLAG_TAPE_FROZEN);
                        softc->flags &= ~SA_FLAG_ERR_PENDING;
                        break;
                case MTOFFL:    /* rewind and put the drive offline */

                        PENDING_MOUNT_CHECK(softc, periph, dev);

                        sacheckeod(periph);
                        /* see above */
                        softc->flags &= ~SA_FLAG_TAPE_WRITTEN;
                        softc->filemarks = 0;

                        error = sarewind(periph);
                        /* clear the frozen flag anyway */
                        softc->flags &= ~SA_FLAG_TAPE_FROZEN;

                        /*
                         * Be sure to allow media removal before ejecting.
                         */

                        saprevent(periph, PR_ALLOW);
                        if (error == 0) {
                                error = saloadunload(periph, FALSE);
                                if (error == 0) {
                                        softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
                                }
                        }
                        break;

                case MTNOP:     /* no operation, sets status only */
                case MTCACHE:   /* enable controller cache */
                case MTNOCACHE: /* disable controller cache */
                        error = 0;
                        break;

                case MTSETBSIZ: /* Set block size for device */

                        PENDING_MOUNT_CHECK(softc, periph, dev);

                        error = sasetparams(periph, SA_PARAM_BLOCKSIZE, count,
                                            0, 0, 0);
                        if (error == 0) {
                                softc->last_media_blksize =
                                    softc->media_blksize;
                                softc->media_blksize = count;
                                if (count) {
                                        softc->flags |= SA_FLAG_FIXED;
                                        if (powerof2(count)) {
                                                softc->blk_shift =
                                                    ffs(count) - 1;
                                                softc->blk_mask = count - 1;
                                        } else {
                                                softc->blk_mask = ~0;
                                                softc->blk_shift = 0;
                                        }
                                        /*
                                         * Make the user's desire 'persistent'.
                                         */
                                        softc->quirks &= ~SA_QUIRK_VARIABLE;
                                        softc->quirks |= SA_QUIRK_FIXED;
                                } else {
                                        softc->flags &= ~SA_FLAG_FIXED;
                                        if (softc->max_blk == 0) {
                                                softc->max_blk = ~0;
                                        }
                                        softc->blk_shift = 0;
                                        if (softc->blk_gran != 0) {
                                                softc->blk_mask =
                                                    softc->blk_gran - 1;
                                        } else {
                                                softc->blk_mask = 0;
                                        }
                                        /*
                                         * Make the user's desire 'persistent'.
                                         */
                                        softc->quirks |= SA_QUIRK_VARIABLE;
                                        softc->quirks &= ~SA_QUIRK_FIXED;
                                }
                        }
                        break;
                case MTSETDNSTY:        /* Set density for device and mode */
                        PENDING_MOUNT_CHECK(softc, periph, dev);

                        if (count > UCHAR_MAX) {
                                error = EINVAL; 
                                break;
                        } else {
                                error = sasetparams(periph, SA_PARAM_DENSITY,
                                                    0, count, 0, 0);
                        }
                        break;
                case MTCOMP:    /* enable compression */
                        PENDING_MOUNT_CHECK(softc, periph, dev);
                        /*
                         * Some devices don't support compression, and
                         * don't like it if you ask them for the
                         * compression page.
                         */
                        if ((softc->quirks & SA_QUIRK_NOCOMP) ||
                            (softc->flags & SA_FLAG_COMP_UNSUPP)) {
                                error = ENODEV;
                                break;
                        }
                        error = sasetparams(periph, SA_PARAM_COMPRESSION,
                            0, 0, count, SF_NO_PRINT);
                        break;
                default:
                        error = EINVAL;
                }
                break;
        }
        case MTIOCIEOT:
        case MTIOCEEOT:
                error = 0;
                break;
        case MTIOCRDSPOS:
                PENDING_MOUNT_CHECK(softc, periph, dev);
                error = sardpos(periph, 0, (u_int32_t *) addr);
                break;
        case MTIOCRDHPOS:
                PENDING_MOUNT_CHECK(softc, periph, dev);
                error = sardpos(periph, 1, (u_int32_t *) addr);
                break;
        case MTIOCSLOCATE:
                PENDING_MOUNT_CHECK(softc, periph, dev);
                error = sasetpos(periph, 0, (u_int32_t *) addr);
                break;
        case MTIOCHLOCATE:
                PENDING_MOUNT_CHECK(softc, periph, dev);
                error = sasetpos(periph, 1, (u_int32_t *) addr);
                break;
        case MTIOCGETEOTMODEL:
                error = 0;
                if (softc->quirks & SA_QUIRK_1FM)
                        mode = 1;
                else
                        mode = 2;
                *((u_int32_t *) addr) = mode;
                break;
        case MTIOCSETEOTMODEL:
                error = 0;
                switch (*((u_int32_t *) addr)) {
                case 1:
                        softc->quirks &= ~SA_QUIRK_2FM;
                        softc->quirks |= SA_QUIRK_1FM;
                        break;
                case 2:
                        softc->quirks &= ~SA_QUIRK_1FM;
                        softc->quirks |= SA_QUIRK_2FM;
                        break;
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = cam_periph_ioctl(periph, ap->a_cmd, addr, saerror);
                break;
        }

        /*
         * Check to see if we cleared a frozen state
         */
        if (error == 0 && (softc->flags & SA_FLAG_TAPE_FROZEN)) {
                switch(ap->a_cmd) {
                case MTIOCRDSPOS:
                case MTIOCRDHPOS:
                case MTIOCSLOCATE:
                case MTIOCHLOCATE:
                        softc->fileno = (daddr_t) -1;
                        softc->blkno = (daddr_t) -1;
                        softc->flags &= ~SA_FLAG_TAPE_FROZEN;
                        xpt_print(periph->path,
                            "tape state now unfrozen.\n");
                        break;
                default:
                        break;
                }
        }
        if (didholdperiph)
                cam_periph_unhold(periph, 1);
        else
                cam_periph_unlock(periph);
        return (error);
}

static void
sainit(void)
{
        cam_status status;

        /*
         * Create our extend array for storing the devices we attach to.
         */
        saperiphs = cam_extend_new();
        if (saperiphs == NULL) {
                kprintf("sa: Failed to alloc extend array!\n");
                return;
        }
        
        /*
         * Install a global async callback.
         */
        status = xpt_register_async(AC_FOUND_DEVICE, saasync, NULL, NULL);

        if (status != CAM_REQ_CMP) {
                kprintf("sa: Failed to attach master async callback "
                       "due to status 0x%x!\n", status);
        }
}

static void
saoninvalidate(struct cam_periph *periph)
{
        struct sa_softc *softc;
        struct buf *q_bp;
        struct bio *q_bio;

        softc = (struct sa_softc *)periph->softc;

        /*
         * De-register any async callbacks.
         */
        xpt_register_async(0, saasync, periph, periph->path);

        softc->flags |= SA_FLAG_INVALID;

        /*
         * Return all queued I/O with ENXIO.
         * XXX Handle any transactions queued to the card
         *     with XPT_ABORT_CCB.
         */
        while ((q_bio = bioq_takefirst(&softc->bio_queue)) != NULL) {
                q_bp = q_bio->bio_buf;
                q_bp->b_resid = q_bp->b_bcount;
                q_bp->b_error = ENXIO;
                q_bp->b_flags |= B_ERROR;
                biodone(q_bio);
        }
        softc->queue_count = 0;

        xpt_print(periph->path, "lost device\n");

}

static void
sacleanup(struct cam_periph *periph)
{
        struct sa_softc *softc;

        softc = (struct sa_softc *)periph->softc;

        devstat_remove_entry(&softc->device_stats);

        cam_extend_release(saperiphs, periph->unit_number);
        xpt_print(periph->path, "removing device entry\n");
        dev_ops_remove_minor(&sa_ops, /*SA_UNITMASK,*/ SA_UNIT(periph->unit_number));
        kfree(softc, M_SCSISA);
}

static void
saasync(void *callback_arg, u_int32_t code,
        struct cam_path *path, void *arg)
{
        struct cam_periph *periph;

        periph = (struct cam_periph *)callback_arg;
        switch (code) {
        case AC_FOUND_DEVICE:
        {
                struct ccb_getdev *cgd;
                cam_status status;

                cgd = (struct ccb_getdev *)arg;
                if (cgd == NULL)
                        break;

                if (SID_TYPE(&cgd->inq_data) != T_SEQUENTIAL)
                        break;

                /*
                 * Allocate a peripheral instance for
                 * this device and start the probe
                 * process.
                 */
                status = cam_periph_alloc(saregister, saoninvalidate,
                                          sacleanup, sastart,
                                          "sa", CAM_PERIPH_BIO, cgd->ccb_h.path,
                                          saasync, AC_FOUND_DEVICE, cgd);

                if (status != CAM_REQ_CMP
                 && status != CAM_REQ_INPROG)
                        kprintf("saasync: Unable to probe new device "
                                "due to status 0x%x\n", status);
                break;
        }
        default:
                cam_periph_async(periph, code, path, arg);
                break;
        }
}

static cam_status
saregister(struct cam_periph *periph, void *arg)
{
        struct sa_softc *softc;
        struct ccb_getdev *cgd;
        caddr_t match;
        int i;
        
        cgd = (struct ccb_getdev *)arg;
        if (periph == NULL) {
                kprintf("saregister: periph was NULL!!\n");
                return (CAM_REQ_CMP_ERR);
        }

        if (cgd == NULL) {
                kprintf("saregister: no getdev CCB, can't register device\n");
                return (CAM_REQ_CMP_ERR);
        }

        softc = kmalloc(sizeof (*softc), M_SCSISA, M_INTWAIT | M_ZERO);
        softc->scsi_rev = SID_ANSI_REV(&cgd->inq_data);
        softc->state = SA_STATE_NORMAL;
        softc->fileno = (daddr_t) -1;
        softc->blkno = (daddr_t) -1;

        bioq_init(&softc->bio_queue);
        periph->softc = softc;
        cam_extend_set(saperiphs, periph->unit_number, periph);

        /*
         * See if this device has any quirks.
         */
        match = cam_quirkmatch((caddr_t)&cgd->inq_data,
                               (caddr_t)sa_quirk_table,
                               NELEM(sa_quirk_table),
                               sizeof(*sa_quirk_table), scsi_inquiry_match);

        if (match != NULL) {
                softc->quirks = ((struct sa_quirk_entry *)match)->quirks;
                softc->last_media_blksize =
                    ((struct sa_quirk_entry *)match)->prefblk;
#ifdef  CAMDEBUG
                xpt_print(periph->path, "found quirk entry %d\n",
                    (int) (((struct sa_quirk_entry *) match) - sa_quirk_table));
#endif
        } else
                softc->quirks = SA_QUIRK_NONE;

        /*
         * The SA driver supports a blocksize, but we don't know the
         * blocksize until we media is inserted.  So, set a flag to
         * indicate that the blocksize is unavailable right now.
         */
        cam_periph_unlock(periph);
        devstat_add_entry(&softc->device_stats, "sa", periph->unit_number, 0,
            DEVSTAT_BS_UNAVAILABLE, SID_TYPE(&cgd->inq_data) |
            DEVSTAT_TYPE_IF_SCSI, DEVSTAT_PRIORITY_TAPE);

        make_dev(&sa_ops, SAMINOR(SA_CTLDEV,
            periph->unit_number, 0, SA_ATYPE_R), UID_ROOT, GID_OPERATOR,
            0660, "%s%d.ctl", periph->periph_name, periph->unit_number);

        make_dev(&sa_ops, SAMINOR(SA_NOT_CTLDEV,
            periph->unit_number, 0, SA_ATYPE_R), UID_ROOT, GID_OPERATOR,
            0660, "%s%d", periph->periph_name, periph->unit_number);

        make_dev(&sa_ops, SAMINOR(SA_NOT_CTLDEV,
            periph->unit_number, 0, SA_ATYPE_NR), UID_ROOT, GID_OPERATOR,
            0660, "n%s%d", periph->periph_name, periph->unit_number);

        make_dev(&sa_ops, SAMINOR(SA_NOT_CTLDEV,
            periph->unit_number, 0, SA_ATYPE_ER), UID_ROOT, GID_OPERATOR,
            0660, "e%s%d", periph->periph_name, periph->unit_number);

        for (i = 0; i < SA_NUM_MODES; i++) {

                make_dev(&sa_ops,
                    SAMINOR(SA_NOT_CTLDEV, periph->unit_number, i, SA_ATYPE_R),
                    UID_ROOT, GID_OPERATOR, 0660, "%s%d.%d",
                    periph->periph_name, periph->unit_number, i);

                make_dev(&sa_ops,
                    SAMINOR(SA_NOT_CTLDEV, periph->unit_number, i, SA_ATYPE_NR),
                    UID_ROOT, GID_OPERATOR, 0660, "n%s%d.%d",
                    periph->periph_name, periph->unit_number, i);


                make_dev(&sa_ops,
                    SAMINOR(SA_NOT_CTLDEV, periph->unit_number, i, SA_ATYPE_ER),
                    UID_ROOT, GID_OPERATOR, 0660, "e%s%d.%d",
                    periph->periph_name, periph->unit_number, i);
        }
        cam_periph_lock(periph);

        /*
         * Add an async callback so that we get
         * notified if this device goes away.
         */
        xpt_register_async(AC_LOST_DEVICE, saasync, periph, periph->path);

        xpt_announce_periph(periph, NULL);

        return (CAM_REQ_CMP);
}

static void
sastart(struct cam_periph *periph, union ccb *start_ccb)
{
        struct sa_softc *softc;

        softc = (struct sa_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE, ("sastart\n"));

        
        switch (softc->state) {
        case SA_STATE_NORMAL:
        {
                /* Pull a buffer from the queue and get going on it */          
                struct buf *bp;
                struct bio *bio;

                /*
                 * See if there is a buf with work for us to do..
                 */
                bio = bioq_first(&softc->bio_queue);
                if (periph->immediate_priority <= periph->pinfo.priority) {
                        CAM_DEBUG_PRINT(CAM_DEBUG_SUBTRACE,
                                        ("queuing for immediate ccb\n"));
                        Set_CCB_Type(start_ccb, SA_CCB_WAITING);
                        SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
                                          periph_links.sle);
                        periph->immediate_priority = CAM_PRIORITY_NONE;
                        wakeup(&periph->ccb_list);
                } else if (bio == NULL) {
                        xpt_release_ccb(start_ccb);
                } else if ((softc->flags & SA_FLAG_ERR_PENDING) != 0) {
                        struct bio *done_bio;
again:
                        softc->queue_count--;
                        bioq_remove(&softc->bio_queue, bio);
                        bp = bio->bio_buf;
                        bp->b_resid = bp->b_bcount;
                        done_bio = bio;
                        if ((softc->flags & SA_FLAG_EOM_PENDING) != 0) {
                                /*
                                 * We now just clear errors in this case
                                 * and let the residual be the notifier.
                                 */
                                bp->b_error = 0;
                        } else if ((softc->flags & SA_FLAG_EOF_PENDING) != 0) {
                                /*
                                 * This can only happen if we're reading
                                 * in fixed length mode. In this case,
                                 * we dump the rest of the list the
                                 * same way.
                                 */
                                bp->b_error = 0;
                                if (bioq_first(&softc->bio_queue) != NULL) {
                                        biodone(done_bio);
                                        goto again;
                                }
                        } else if ((softc->flags & SA_FLAG_EIO_PENDING) != 0) {
                                bp->b_error = EIO;
                                bp->b_flags |= B_ERROR;
                        }
                        bio = bioq_first(&softc->bio_queue);
                        /*
                         * Only if we have no other buffers queued up
                         * do we clear the pending error flag.
                         */
                        if (bio == NULL)
                                softc->flags &= ~SA_FLAG_ERR_PENDING;
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                            ("sastart- ERR_PENDING now 0x%x, bio is %sNULL, "
                            "%d more buffers queued up\n",
                            (softc->flags & SA_FLAG_ERR_PENDING),
                            (bio != NULL)? "not " : " ", softc->queue_count));
                        xpt_release_ccb(start_ccb);
                        biodone(done_bio);
                } else {
                        u_int32_t length;

                        bioq_remove(&softc->bio_queue, bio);
                        bp = bio->bio_buf;
                        softc->queue_count--;

                        if ((softc->flags & SA_FLAG_FIXED) != 0) {
                                if (softc->blk_shift != 0) {
                                        length =
                                            bp->b_bcount >> softc->blk_shift;
                                } else if (softc->media_blksize != 0) {
                                        length =
                                            bp->b_bcount / softc->media_blksize;
                                } else {
                                        bp->b_error = EIO;
                                        xpt_print(periph->path, "zero blocksize"
                                            " for FIXED length writes?\n");
                                        biodone(bio);
                                        break;
                                }
#if     0
                                CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_INFO,
                                    ("issuing a %d fixed record %s\n",
                                    length,  (bp->bio_cmd == BIO_READ)? "read" :
                                    "write"));
#endif
                        } else {
                                length = bp->b_bcount;
#if     0
                                CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_INFO,
                                    ("issuing a %d variable byte %s\n",
                                    length,  (bp->bio_cmd == BIO_READ)? "read" :
                                    "write"));
#endif
                        }
                        devstat_start_transaction(&softc->device_stats);
                        /*
                         * Some people have theorized that we should
                         * suppress illegal length indication if we are
                         * running in variable block mode so that we don't
                         * have to request sense every time our requested
                         * block size is larger than the written block.
                         * The residual information from the ccb allows
                         * us to identify this situation anyway.  The only
                         * problem with this is that we will not get
                         * information about blocks that are larger than
                         * our read buffer unless we set the block size
                         * in the mode page to something other than 0.
                         *
                         * I believe that this is a non-issue. If user apps
                         * don't adjust their read size to match our record
                         * size, that's just life. Anyway, the typical usage
                         * would be to issue, e.g., 64KB reads and occasionally
                         * have to do deal with 512 byte or 1KB intermediate
                         * records.
                         */
                        softc->dsreg = (bp->b_cmd == BUF_CMD_READ) ?
                            MTIO_DSREG_RD : MTIO_DSREG_WR;
                        scsi_sa_read_write(&start_ccb->csio, 0, sadone,
                            MSG_SIMPLE_Q_TAG, (bp->b_cmd == BUF_CMD_READ) != 0,
                            FALSE, (softc->flags & SA_FLAG_FIXED) != 0,
                            length, bp->b_data, bp->b_bcount, SSD_FULL_SIZE,
                            IO_TIMEOUT);
                        start_ccb->ccb_h.ccb_pflags &= ~SA_POSITION_UPDATED;
                        Set_CCB_Type(start_ccb, SA_CCB_BUFFER_IO);
                        start_ccb->ccb_h.ccb_bio = bio;
                        bio = bioq_first(&softc->bio_queue);
                        xpt_action(start_ccb);
                }
                
                if (bio != NULL) {
                        /* Have more work to do, so ensure we stay scheduled */
                        xpt_schedule(periph, 1);
                }
                break;
        }
        case SA_STATE_ABNORMAL:
        default:
                panic("state 0x%x in sastart", softc->state);
                break;
        }
}


static void
sadone(struct cam_periph *periph, union ccb *done_ccb)
{
        struct sa_softc *softc;
        struct ccb_scsiio *csio;

        softc = (struct sa_softc *)periph->softc;
        csio = &done_ccb->csio;

        switch (CCB_Type(csio)) {
        case SA_CCB_BUFFER_IO:
        {
                struct buf *bp;
                struct bio *bio;
                int error;

                softc->dsreg = MTIO_DSREG_REST;
                bio = (struct bio *)done_ccb->ccb_h.ccb_bio;
                bp = bio->bio_buf;
                error = 0;
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        if ((error = saerror(done_ccb, 0, 0)) == ERESTART) {
                                /*
                                 * A retry was scheduled, so just return.
                                 */
                                return;
                        }
                }

                if (error == EIO) {
                        struct buf *q_bp;
                        struct bio *q_bio;

                        /*
                         * Catastrophic error. Mark the tape as frozen
                         * (we no longer know tape position).
                         *
                         * Return all queued I/O with EIO, and unfreeze
                         * our queue so that future transactions that
                         * attempt to fix this problem can get to the
                         * device.
                         *
                         */

                        softc->flags |= SA_FLAG_TAPE_FROZEN;
                        while ((q_bio = bioq_takefirst(&softc->bio_queue)) != NULL) {
                                q_bp = q_bio->bio_buf;
                                q_bp->b_resid = q_bp->b_bcount;
                                q_bp->b_error = EIO;
                                q_bp->b_flags |= B_ERROR;
                                biodone(q_bio);
                        }
                }
                if (error != 0) {
                        bp->b_resid = bp->b_bcount;
                        bp->b_error = error;
                        bp->b_flags |= B_ERROR;
                        /*
                         * In the error case, position is updated in saerror.
                         */
                } else {
                        bp->b_resid = csio->resid;
                        bp->b_error = 0;
                        if (csio->resid != 0) {
                                bp->b_flags |= B_ERROR;
                        }
                        if (bp->b_cmd != BUF_CMD_READ) {
                                softc->flags |= SA_FLAG_TAPE_WRITTEN;
                                softc->filemarks = 0;
                        }
                        if (!(csio->ccb_h.ccb_pflags & SA_POSITION_UPDATED) &&
                            (softc->blkno != (daddr_t) -1)) {
                                if ((softc->flags & SA_FLAG_FIXED) != 0) {
                                        u_int32_t l;
                                        if (softc->blk_shift != 0) {
                                                l = bp->b_bcount >>
                                                        softc->blk_shift;
                                        } else {
                                                l = bp->b_bcount /
                                                        softc->media_blksize;
                                        }
                                        softc->blkno += (daddr_t) l;
                                } else {
                                        softc->blkno++;
                                }
                        }
                }
                /*
                 * If we had an error (immediate or pending),
                 * release the device queue now.
                 */
                if (error || (softc->flags & SA_FLAG_ERR_PENDING))
                        cam_release_devq(done_ccb->ccb_h.path, 0, 0, 0, 0);
#ifdef  CAMDEBUG
                if (error || bp->b_resid) {
                        CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                                  ("error %d resid %d count %d\n", error,
                                  bp->b_resid, bp->b_bcount));
                }
#endif
                devstat_end_transaction_buf(&softc->device_stats, bp);
                biodone(bio);
                break;
        }
        case SA_CCB_WAITING:
        {
                /* Caller will release the CCB */
                wakeup(&done_ccb->ccb_h.cbfcnp);
                return;
        }
        case SA_CCB_POLLED:
                /* polled, caller releases ccb */
                wakeup(&done_ccb->ccb_h.cbfcnp);
                return;
        }
        xpt_release_ccb(done_ccb);
}

/*
 * Mount the tape (make sure it's ready for I/O).
 *
 * oflags can be checked for 'kind' of open (read-only check) - later
 * dev can be checked for a control-mode or compression open - later
 */
static int
samount(struct cam_periph *periph, __unused int oflags, __unused cdev_t dev)
{
        struct  sa_softc *softc;
        union   ccb *ccb;
        int     error;

        softc = (struct sa_softc *)periph->softc;

        /*
         * This should determine if something has happend since the last
         * open/mount that would invalidate the mount. We do *not* want
         * to retry this command- we just want the status. But we only
         * do this if we're mounted already- if we're not mounted,
         * we don't care about the unit read state and can instead use
         * this opportunity to attempt to reserve the tape unit.
         */
        
        if (softc->flags & SA_FLAG_TAPE_MOUNTED) {
                ccb = cam_periph_getccb(periph, 1);
                Set_CCB_Type(ccb, SA_CCB_POLLED);

                scsi_test_unit_ready(&ccb->csio, 0, sadone,
                                     MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE,
                                     IO_TIMEOUT);
                error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                                          &softc->device_stats);
                QFRLS(ccb);
                if (error == ENXIO) {
                        softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
                        scsi_test_unit_ready(&ccb->csio, 0, sadone,
                            MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE, IO_TIMEOUT);
                        error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                            &softc->device_stats);
                        QFRLS(ccb);
                } else if (error) {
                        /*
                         * We don't need to freeze the tape because we
                         * will now attempt to rewind/load it.
                         */
                        softc->flags &= ~SA_FLAG_TAPE_MOUNTED;
                        if (CAM_DEBUGGED(periph->path, CAM_DEBUG_INFO)) {
                                xpt_print(periph->path,
                                    "error %d on TUR in samount\n", error);
                        }
                }
        } else {
                error = sareservereleaseunit(periph, TRUE);
                if (error) {
                        return (error);
                }
                ccb = cam_periph_getccb(periph, 1);
                Set_CCB_Type(ccb, SA_CCB_POLLED);
                scsi_test_unit_ready(&ccb->csio, 0, sadone,
                                     MSG_SIMPLE_Q_TAG, SSD_FULL_SIZE,
                                     IO_TIMEOUT);
                error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                                          &softc->device_stats);
                QFRLS(ccb);
        }

        if ((softc->flags & SA_FLAG_TAPE_MOUNTED) == 0) {
                struct scsi_read_block_limits_data *rblim = NULL;
                int comp_enabled = 0;           /* silence gcc */
                int comp_supported = 0;         /* silence gcc */
                u_int8_t write_protect = 0;     /* silence gcc */
                u_int8_t guessing = 0;

                /*
                 * Clear out old state.
                 */
                softc->flags &= ~(SA_FLAG_TAPE_WP|SA_FLAG_TAPE_WRITTEN|
                                  SA_FLAG_ERR_PENDING|SA_FLAG_COMP_ENABLED|
                                  SA_FLAG_COMP_SUPP|SA_FLAG_COMP_UNSUPP);
                softc->filemarks = 0;

                /*
                 * *Very* first off, make sure we're loaded to BOT.
                 */
                scsi_load_unload(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG, FALSE,
                    FALSE, FALSE, 1, SSD_FULL_SIZE, REWIND_TIMEOUT);
                error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                    &softc->device_stats);
                QFRLS(ccb);

                /*
                 * In case this doesn't work, do a REWIND instead
                 */
                if (error) {
                        scsi_rewind(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG,
                            FALSE, SSD_FULL_SIZE, REWIND_TIMEOUT);
                        error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                                &softc->device_stats);
                        QFRLS(ccb);
                }
                if (error) {
                        xpt_release_ccb(ccb);
                        goto exit;
                }

                /*
                 * Do a dummy test read to force access to the
                 * media so that the drive will really know what's
                 * there. We actually don't really care what the
                 * blocksize on tape is and don't expect to really
                 * read a full record.
                 */
                rblim = kmalloc(8192, M_SCSISA, M_INTWAIT);

                if ((softc->quirks & SA_QUIRK_NODREAD) == 0) {
                        scsi_sa_read_write(&ccb->csio, 0, sadone,
                            MSG_SIMPLE_Q_TAG, 1, FALSE, 0, 8192,
                            (void *) rblim, 8192, SSD_FULL_SIZE,
                            IO_TIMEOUT);
                        cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                            &softc->device_stats);
                        QFRLS(ccb);
                        scsi_rewind(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG,
                            FALSE, SSD_FULL_SIZE, REWIND_TIMEOUT);
                        error = cam_periph_runccb(ccb, saerror, CAM_RETRY_SELTO,
                            SF_NO_PRINT | SF_RETRY_UA,
                            &softc->device_stats);
                        QFRLS(ccb);
                        if (error) {
                                xpt_print(periph->path,
                                    "unable to rewind after test read\n");
                                xpt_release_ccb(ccb);
                                goto exit;
                        }
                }

                /*
                 * Next off, determine block limits.
                 */
                scsi_read_block_limits(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG,
                    rblim, SSD_FULL_SIZE, SCSIOP_TIMEOUT);

                error = cam_periph_runccb(ccb, saerror, CAM_RETRY_SELTO,
                    SF_NO_PRINT | SF_RETRY_UA, &softc->device_stats);

                QFRLS(ccb);
                xpt_release_ccb(ccb);

                if (error != 0) {
                        /*
                         * If it's less than SCSI-2, READ BLOCK LIMITS is not
                         * a MANDATORY command. Anyway- it doesn't matter-
                         * we can proceed anyway.
                         */
                        softc->blk_gran = 0;
                        softc->max_blk = ~0;
                        softc->min_blk = 0;
                } else {
                        if (softc->scsi_rev >= SCSI_REV_SPC) {
                                softc->blk_gran = RBL_GRAN(rblim);
                        } else {
                                softc->blk_gran = 0;
                        }
                        /*
                         * We take max_blk == min_blk to mean a default to
                         * fixed mode- but note that whatever we get out of
                         * sagetparams below will actually determine whether
                         * we are actually *in* fixed mode.
                         */
                        softc->max_blk = scsi_3btoul(rblim->maximum);
                        softc->min_blk = scsi_2btoul(rblim->minimum);


                }
                /*
                 * Next, perform a mode sense to determine
                 * current density, blocksize, compression etc.
                 */
                error = sagetparams(periph, SA_PARAM_ALL,
                                    &softc->media_blksize,
                                    &softc->media_density,
                                    &softc->media_numblks,
                                    &softc->buffer_mode, &write_protect,
                                    &softc->speed, &comp_supported,
                                    &comp_enabled, &softc->comp_algorithm,
                                    NULL);

                if (error != 0) {
                        /*
                         * We could work a little harder here. We could
                         * adjust our attempts to get information. It
                         * might be an ancient tape drive. If someone
                         * nudges us, we'll do that.
                         */
                        goto exit;
                }

                /*
                 * If no quirk has determined that this is a device that is
                 * preferred to be in fixed or variable mode, now is the time
                 * to find out.
                 */
                if ((softc->quirks & (SA_QUIRK_FIXED|SA_QUIRK_VARIABLE)) == 0) {
                        guessing = 1;
                        /*
                         * This could be expensive to find out. Luckily we
                         * only need to do this once. If we start out in
                         * 'default' mode, try and set ourselves to one
                         * of the densities that would determine a wad
                         * of other stuff. Go from highest to lowest.
                         */
                        if (softc->media_density == SCSI_DEFAULT_DENSITY) {
                                int i;
                                static u_int8_t ctry[] = {
                                        SCSI_DENSITY_HALFINCH_PE,
                                        SCSI_DENSITY_HALFINCH_6250C,
                                        SCSI_DENSITY_HALFINCH_6250,
                                        SCSI_DENSITY_HALFINCH_1600,
                                        SCSI_DENSITY_HALFINCH_800,
                                        SCSI_DENSITY_QIC_4GB,
                                        SCSI_DENSITY_QIC_2GB,
                                        SCSI_DENSITY_QIC_525_320,
                                        SCSI_DENSITY_QIC_150,
                                        SCSI_DENSITY_QIC_120,
                                        SCSI_DENSITY_QIC_24,
                                        SCSI_DENSITY_QIC_11_9TRK,
                                        SCSI_DENSITY_QIC_11_4TRK,
                                        SCSI_DENSITY_QIC_1320,
                                        SCSI_DENSITY_QIC_3080,
                                        0
                                };
                                for (i = 0; ctry[i]; i++) {
                                        error = sasetparams(periph,
                                            SA_PARAM_DENSITY, 0, ctry[i],
                                            0, SF_NO_PRINT);
                                        if (error == 0) {
                                                softc->media_density = ctry[i];
                                                break;
                                        }
                                }
                        }
                        switch (softc->media_density) {
                        case SCSI_DENSITY_QIC_11_4TRK:
                        case SCSI_DENSITY_QIC_11_9TRK:
                        case SCSI_DENSITY_QIC_24:
                        case SCSI_DENSITY_QIC_120:
                        case SCSI_DENSITY_QIC_150:
                        case SCSI_DENSITY_QIC_525_320:
                        case SCSI_DENSITY_QIC_1320:
                        case SCSI_DENSITY_QIC_3080:
                                softc->quirks &= ~SA_QUIRK_2FM;
                                softc->quirks |= SA_QUIRK_FIXED|SA_QUIRK_1FM;
                                softc->last_media_blksize = 512;
                                break;
                        case SCSI_DENSITY_QIC_4GB:
                        case SCSI_DENSITY_QIC_2GB:
                                softc->quirks &= ~SA_QUIRK_2FM;
                                softc->quirks |= SA_QUIRK_FIXED|SA_QUIRK_1FM;
                                softc->last_media_blksize = 1024;
                                break;
                        default:
                                softc->last_media_blksize =
                                    softc->media_blksize;
                                softc->quirks |= SA_QUIRK_VARIABLE;
                                break;
                        }
                }

                /*
                 * If no quirk has determined that this is a device that needs
                 * to have 2 Filemarks at EOD, now is the time to find out.
                 */

                if ((softc->quirks & SA_QUIRK_2FM) == 0) {
                        switch (softc->media_density) {
                        case SCSI_DENSITY_HALFINCH_800:
                        case SCSI_DENSITY_HALFINCH_1600:
                        case SCSI_DENSITY_HALFINCH_6250:
                        case SCSI_DENSITY_HALFINCH_6250C:
                        case SCSI_DENSITY_HALFINCH_PE:
                                softc->quirks &= ~SA_QUIRK_1FM;
                                softc->quirks |= SA_QUIRK_2FM;
                                break;
                        default:
                                break;
                        }
                }

                /*
                 * Now validate that some info we got makes sense.
                 */
                if ((softc->max_blk < softc->media_blksize) ||
                    (softc->min_blk > softc->media_blksize &&
                    softc->media_blksize)) {
                        xpt_print(periph->path,
                            "BLOCK LIMITS (%d..%d) could not match current "
                            "block settings (%d)- adjusting\n", softc->min_blk,
                            softc->max_blk, softc->media_blksize);
                        softc->max_blk = softc->min_blk =
                            softc->media_blksize;
                }

                /*
                 * Now put ourselves into the right frame of mind based
                 * upon quirks...
                 */
tryagain:
                /*
                 * If we want to be in FIXED mode and our current blocksize
                 * is not equal to our last blocksize (if nonzero), try and
                 * set ourselves to this last blocksize (as the 'preferred'
                 * block size).  The initial quirkmatch at registry sets the
                 * initial 'last' blocksize. If, for whatever reason, this
                 * 'last' blocksize is zero, set the blocksize to 512,
                 * or min_blk if that's larger.
                 */
                if ((softc->quirks & SA_QUIRK_FIXED) &&
                    (softc->quirks & SA_QUIRK_NO_MODESEL) == 0 &&
                    (softc->media_blksize != softc->last_media_blksize)) {
                        softc->media_blksize = softc->last_media_blksize;
                        if (softc->media_blksize == 0) {
                                softc->media_blksize = 512;
                                if (softc->media_blksize < softc->min_blk) {
                                        softc->media_blksize = softc->min_blk;
                                }
                        }
                        error = sasetparams(periph, SA_PARAM_BLOCKSIZE,
                            softc->media_blksize, 0, 0, SF_NO_PRINT);
                        if (error) {
                                xpt_print(periph->path,
                                    "unable to set fixed blocksize to %d\n",
                                    softc->media_blksize);
                                goto exit;
                        }
                }

                if ((softc->quirks & SA_QUIRK_VARIABLE) && 
                    (softc->media_blksize != 0)) {
                        softc->last_media_blksize = softc->media_blksize;
                        softc->media_blksize = 0;
                        error = sasetparams(periph, SA_PARAM_BLOCKSIZE,
                            0, 0, 0, SF_NO_PRINT);
                        if (error) {
                                /*
                                 * If this fails and we were guessing, just
                                 * assume that we got it wrong and go try
                                 * fixed block mode. Don't even check against
                                 * density code at this point.
                                 */
                                if (guessing) {
                                        softc->quirks &= ~SA_QUIRK_VARIABLE;
                                        softc->quirks |= SA_QUIRK_FIXED;
                                        if (softc->last_media_blksize == 0)
                                                softc->last_media_blksize = 512;
                                        goto tryagain;
                                }
                                xpt_print(periph->path,
                                    "unable to set variable blocksize\n");
                                goto exit;
                        }
                }

                /*
                 * Now that we have the current block size,
                 * set up some parameters for sastart's usage.
                 */
                if (softc->media_blksize) {
                        softc->flags |= SA_FLAG_FIXED;
                        if (powerof2(softc->media_blksize)) {
                                softc->blk_shift =
                                    ffs(softc->media_blksize) - 1;
                                softc->blk_mask = softc->media_blksize - 1;
                        } else {
                                softc->blk_mask = ~0;
                                softc->blk_shift = 0;
                        }
                } else {
                        /*
                         * The SCSI-3 spec allows 0 to mean "unspecified".
                         * The SCSI-1 spec allows 0 to mean 'infinite'.
                         *
                         * Either works here.
                         */
                        if (softc->max_blk == 0) {
                                softc->max_blk = ~0;
                        }
                        softc->blk_shift = 0;
                        if (softc->blk_gran != 0) {
                                softc->blk_mask = softc->blk_gran - 1;
                        } else {
                                softc->blk_mask = 0;
                        }
                }

                if (write_protect) 
                        softc->flags |= SA_FLAG_TAPE_WP;

                if (comp_supported) {
                        if (softc->saved_comp_algorithm == 0)
                                softc->saved_comp_algorithm =
                                    softc->comp_algorithm;
                        softc->flags |= SA_FLAG_COMP_SUPP;
                        if (comp_enabled)
                                softc->flags |= SA_FLAG_COMP_ENABLED;
                } else
                        softc->flags |= SA_FLAG_COMP_UNSUPP;

                if ((softc->buffer_mode == SMH_SA_BUF_MODE_NOBUF) &&
                    (softc->quirks & SA_QUIRK_NO_MODESEL) == 0) {
                        error = sasetparams(periph, SA_PARAM_BUFF_MODE, 0,
                            0, 0, SF_NO_PRINT);
                        if (error == 0) {
                                softc->buffer_mode = SMH_SA_BUF_MODE_SIBUF;
                        } else {
                                xpt_print(periph->path,
                                    "unable to set buffered mode\n");
                        }
                        error = 0;      /* not an error */
                }


                if (error == 0) {
                        softc->flags |= SA_FLAG_TAPE_MOUNTED;
                }
exit:
                if (rblim != NULL)
                        kfree(rblim, M_SCSISA);

                if (error != 0) {
                        softc->dsreg = MTIO_DSREG_NIL;
                } else {
                        softc->fileno = softc->blkno = 0;
                        softc->dsreg = MTIO_DSREG_REST;
                }
#ifdef  SA_1FM_AT_EOD
                if ((softc->quirks & SA_QUIRK_2FM) == 0)
                        softc->quirks |= SA_QUIRK_1FM;
#else
                if ((softc->quirks & SA_QUIRK_1FM) == 0)
                        softc->quirks |= SA_QUIRK_2FM;
#endif
        } else
                xpt_release_ccb(ccb);

        /*
         * If we return an error, we're not mounted any more,
         * so release any device reservation.
         */
        if (error != 0) {
                sareservereleaseunit(periph, FALSE);
        } else {
                /*
                 * Clear I/O residual.
                 */
                softc->last_io_resid = 0;
                softc->last_ctl_resid = 0;
        }
        return (error);
}

/*
 * How many filemarks do we need to write if we were to terminate the
 * tape session right now? Note that this can be a negative number
 */

static int
samarkswanted(struct cam_periph *periph)
{
        int     markswanted;
        struct  sa_softc *softc;

        softc = (struct sa_softc *)periph->softc;
        markswanted = 0;
        if ((softc->flags & SA_FLAG_TAPE_WRITTEN) != 0) {
                markswanted++;
                if (softc->quirks & SA_QUIRK_2FM)
                        markswanted++;
        }
        markswanted -= softc->filemarks;
        return (markswanted);
}

static int
sacheckeod(struct cam_periph *periph)
{
        int     error;
        int     markswanted;

        markswanted = samarkswanted(periph);

        if (markswanted > 0) {
                error = sawritefilemarks(periph, markswanted, FALSE);
        } else {
                error = 0;
        }
        return (error);
}

static int
saerror(union ccb *ccb, u_int32_t cflgs, u_int32_t sflgs)
{
        static const char *toobig =
            "%d-byte tape record bigger than supplied buffer\n";
        struct  cam_periph *periph;
        struct  sa_softc *softc;
        struct  ccb_scsiio *csio;
        struct  scsi_sense_data *sense;
        u_int32_t resid = 0;
        int32_t info = 0;
        cam_status status;
        int error_code, sense_key, asc, ascq, error, aqvalid;

        periph = xpt_path_periph(ccb->ccb_h.path);
        softc = (struct sa_softc *)periph->softc;
        csio = &ccb->csio;
        sense = &csio->sense_data;
        scsi_extract_sense(sense, &error_code, &sense_key, &asc, &ascq);
        aqvalid = sense->extra_len >= 6;
        error = 0;

        status = csio->ccb_h.status & CAM_STATUS_MASK;

        /*
         * Calculate/latch up, any residuals... We do this in a funny 2-step
         * so we can print stuff here if we have CAM_DEBUG enabled for this
         * unit.
         */
        if (status == CAM_SCSI_STATUS_ERROR) {
                if ((sense->error_code & SSD_ERRCODE_VALID) != 0) {
                        info = (int32_t) scsi_4btoul(sense->info);
                        resid = info;
                        if ((softc->flags & SA_FLAG_FIXED) != 0)
                                resid *= softc->media_blksize;
                } else {
                        resid = csio->dxfer_len;
                        info = resid;
                        if ((softc->flags & SA_FLAG_FIXED) != 0) {
                                if (softc->media_blksize)
                                        info /= softc->media_blksize;
                        }
                }
                if (CCB_Type(csio) == SA_CCB_BUFFER_IO) {
                        bcopy((caddr_t) sense, (caddr_t) &softc->last_io_sense,
                            sizeof (struct scsi_sense_data));
                        bcopy(csio->cdb_io.cdb_bytes, softc->last_io_cdb,
                            (int) csio->cdb_len);
                        softc->last_io_resid = resid;
                        softc->last_resid_was_io = 1;
                } else {
                        bcopy((caddr_t) sense, (caddr_t) &softc->last_ctl_sense,
                            sizeof (struct scsi_sense_data));
                        bcopy(csio->cdb_io.cdb_bytes, softc->last_ctl_cdb,
                            (int) csio->cdb_len);
                        softc->last_ctl_resid = resid;
                        softc->last_resid_was_io = 0;
                }
                CAM_DEBUG(periph->path, CAM_DEBUG_INFO, ("CDB[0]=0x%x Key 0x%x "
                    "ASC/ASCQ 0x%x/0x%x CAM STATUS 0x%x flags 0x%x resid %d "
                    "dxfer_len %d\n", csio->cdb_io.cdb_bytes[0] & 0xff,
                    sense_key, asc, ascq, status,
                    sense->flags & ~SSD_KEY_RESERVED, resid, csio->dxfer_len));
        } else {
                CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
                    ("Cam Status 0x%x\n", status));
        }

        switch (status) {
        case CAM_REQ_CMP:
                return (0);
        case CAM_SCSI_STATUS_ERROR:
                /*
                 * If a read/write command, we handle it here.
                 */
                if (CCB_Type(csio) != SA_CCB_WAITING) {
                        break;
                }
                /*
                 * If this was just EOM/EOP, Filemark, Setmark or ILI detected
                 * on a non read/write command, we assume it's not an error
                 * and propagate the residule and return.
                 */
                if ((aqvalid && asc == 0 && ascq > 0 && ascq <= 5) ||
                    (aqvalid == 0 && sense_key == SSD_KEY_NO_SENSE)) {
                        csio->resid = resid;
                        QFRLS(ccb);
                        return (0);
                }
                /*
                 * Otherwise, we let the common code handle this.
                 */
                return (cam_periph_error(ccb, cflgs, sflgs, &softc->saved_ccb));

        /*
         * XXX: To Be Fixed
         * We cannot depend upon CAM honoring retry counts for these.
         */
        case CAM_SCSI_BUS_RESET:
        case CAM_BDR_SENT:
                if (ccb->ccb_h.retry_count <= 0) {
                        return (EIO);
                }
                /* FALLTHROUGH */
        default:
                return (cam_periph_error(ccb, cflgs, sflgs, &softc->saved_ccb));
        }

        /*
         * Handle filemark, end of tape, mismatched record sizes....
         * From this point out, we're only handling read/write cases.
         * Handle writes && reads differently.
         */

        if (csio->cdb_io.cdb_bytes[0] == SA_WRITE) {
                if (sense_key == SSD_KEY_VOLUME_OVERFLOW) {
                        csio->resid = resid;
                        error = ENOSPC;
                } else if (sense->flags & SSD_EOM) {
                        softc->flags |= SA_FLAG_EOM_PENDING;
                        /*
                         * Grotesque as it seems, the few times
                         * I've actually seen a non-zero resid,
                         * the tape drive actually lied and had
                         * written all the data!.
                         */
                        csio->resid = 0;
                }
        } else {
                csio->resid = resid;
                if (sense_key == SSD_KEY_BLANK_CHECK) {
                        if (softc->quirks & SA_QUIRK_1FM) {
                                error = 0;
                                softc->flags |= SA_FLAG_EOM_PENDING;
                        } else {
                                error = EIO;
                        }
                } else if (sense->flags & SSD_FILEMARK) {
                        if (softc->flags & SA_FLAG_FIXED) {
                                error = -1;
                                softc->flags |= SA_FLAG_EOF_PENDING;
                        }
                        /*
                         * Unconditionally, if we detected a filemark on a read,
                         * mark that we've run moved a file ahead.
                         */
                        if (softc->fileno != (daddr_t) -1) {
                                softc->fileno++;
                                softc->blkno = 0;
                                csio->ccb_h.ccb_pflags |= SA_POSITION_UPDATED;
                        }
                }
        }

        /*
         * Incorrect Length usually applies to read, but can apply to writes.
         */
        if (error == 0 && (sense->flags & SSD_ILI)) {
                if (info < 0) {
                        xpt_print(csio->ccb_h.path, toobig,
                            csio->dxfer_len - info);
                        csio->resid = csio->dxfer_len;
                        error = EIO;
                } else {
                        csio->resid = resid;
                        if (softc->flags & SA_FLAG_FIXED) {
                                softc->flags |= SA_FLAG_EIO_PENDING;
                        }
                        /*
                         * Bump the block number if we hadn't seen a filemark.
                         * Do this independent of errors (we've moved anyway).
                         */
                        if ((sense->flags & SSD_FILEMARK) == 0) {
                                if (softc->blkno != (daddr_t) -1) {
                                        softc->blkno++;
                                        csio->ccb_h.ccb_pflags |=
                                           SA_POSITION_UPDATED;
                                }
                        }
                }
        }

        if (error <= 0) {
                /*
                 * Unfreeze the queue if frozen as we're not returning anything
                 * to our waiters that would indicate an I/O error has occurred
                 * (yet).
                 */
                QFRLS(ccb);
                error = 0;
        }
        return (error);
}

static int
sagetparams(struct cam_periph *periph, sa_params params_to_get,
            u_int32_t *blocksize, u_int8_t *density, u_int32_t *numblocks,
            int *buff_mode, u_int8_t *write_protect, u_int8_t *speed,
            int *comp_supported, int *comp_enabled, u_int32_t *comp_algorithm,
            sa_comp_t *tcs)
{
        union ccb *ccb;
        void *mode_buffer;
        struct scsi_mode_header_6 *mode_hdr;
        struct scsi_mode_blk_desc *mode_blk;
        int mode_buffer_len;
        struct sa_softc *softc;
        u_int8_t cpage;
        int error;
        cam_status status;

        softc = (struct sa_softc *)periph->softc;
        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);
        if (softc->quirks & SA_QUIRK_NO_CPAGE)
                cpage = SA_DEVICE_CONFIGURATION_PAGE;
        else
                cpage = SA_DATA_COMPRESSION_PAGE;

retry:
        mode_buffer_len = sizeof(*mode_hdr) + sizeof(*mode_blk);

        if (params_to_get & SA_PARAM_COMPRESSION) {
                if (softc->quirks & SA_QUIRK_NOCOMP) {
                        *comp_supported = FALSE;
                        params_to_get &= ~SA_PARAM_COMPRESSION;
                } else
                        mode_buffer_len += sizeof (sa_comp_t);
        }

        mode_buffer = kmalloc(mode_buffer_len, M_SCSISA, M_INTWAIT | M_ZERO);
        mode_hdr = (struct scsi_mode_header_6 *)mode_buffer;
        mode_blk = (struct scsi_mode_blk_desc *)&mode_hdr[1];

        /* it is safe to retry this */
        scsi_mode_sense(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG, FALSE,
            SMS_PAGE_CTRL_CURRENT, (params_to_get & SA_PARAM_COMPRESSION) ?
            cpage : SMS_VENDOR_SPECIFIC_PAGE, mode_buffer, mode_buffer_len,
            SSD_FULL_SIZE, SCSIOP_TIMEOUT);

        error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
            &softc->device_stats);
        QFRLS(ccb);

        status = ccb->ccb_h.status & CAM_STATUS_MASK;

        if (error == EINVAL && (params_to_get & SA_PARAM_COMPRESSION) != 0) {
                /*
                 * Hmm. Let's see if we can try another page...
                 * If we've already done that, give up on compression
                 * for this device and remember this for the future
                 * and attempt the request without asking for compression
                 * info.
                 */
                if (cpage == SA_DATA_COMPRESSION_PAGE) {
                        cpage = SA_DEVICE_CONFIGURATION_PAGE;
                        goto retry;
                }
                softc->quirks |= SA_QUIRK_NOCOMP;
                kfree(mode_buffer, M_SCSISA);
                goto retry;
        } else if (status == CAM_SCSI_STATUS_ERROR) {
                /* Tell the user about the fatal error. */
                scsi_sense_print(&ccb->csio);
                goto sagetparamsexit;
        }

        /*
         * If the user only wants the compression information, and
         * the device doesn't send back the block descriptor, it's
         * no big deal.  If the user wants more than just
         * compression, though, and the device doesn't pass back the
         * block descriptor, we need to send another mode sense to
         * get the block descriptor.
         */
        if ((mode_hdr->blk_desc_len == 0) &&
            (params_to_get & SA_PARAM_COMPRESSION) &&
            (params_to_get & ~(SA_PARAM_COMPRESSION))) {

                /*
                 * Decrease the mode buffer length by the size of
                 * the compression page, to make sure the data
                 * there doesn't get overwritten.
                 */
                mode_buffer_len -= sizeof (sa_comp_t);

                /*
                 * Now move the compression page that we presumably
                 * got back down the memory chunk a little bit so
                 * it doesn't get spammed.
                 */
                bcopy(&mode_hdr[0], &mode_hdr[1], sizeof (sa_comp_t));
                bzero(&mode_hdr[0], sizeof (mode_hdr[0]));

                /*
                 * Now, we issue another mode sense and just ask
                 * for the block descriptor, etc.
                 */

                scsi_mode_sense(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG, FALSE,
                    SMS_PAGE_CTRL_CURRENT, SMS_VENDOR_SPECIFIC_PAGE,
                    mode_buffer, mode_buffer_len, SSD_FULL_SIZE,
                    SCSIOP_TIMEOUT);

                error = cam_periph_runccb(ccb, saerror, 0, SF_NO_PRINT,
                    &softc->device_stats);
                QFRLS(ccb);

                if (error != 0)
                        goto sagetparamsexit;
        }

        if (params_to_get & SA_PARAM_BLOCKSIZE)
                *blocksize = scsi_3btoul(mode_blk->blklen);

        if (params_to_get & SA_PARAM_NUMBLOCKS)
                *numblocks = scsi_3btoul(mode_blk->nblocks);

        if (params_to_get & SA_PARAM_BUFF_MODE)
                *buff_mode = mode_hdr->dev_spec & SMH_SA_BUF_MODE_MASK;

        if (params_to_get & SA_PARAM_DENSITY)
                *density = mode_blk->density;

        if (params_to_get & SA_PARAM_WP)
                *write_protect = (mode_hdr->dev_spec & SMH_SA_WP)? TRUE : FALSE;

        if (params_to_get & SA_PARAM_SPEED)
                *speed = mode_hdr->dev_spec & SMH_SA_SPEED_MASK;

        if (params_to_get & SA_PARAM_COMPRESSION) {
                sa_comp_t *ntcs = (sa_comp_t *) &mode_blk[1];
                if (cpage == SA_DATA_COMPRESSION_PAGE) {
                        struct scsi_data_compression_page *cp = &ntcs->dcomp;
                        *comp_supported =
                            (cp->dce_and_dcc & SA_DCP_DCC)? TRUE : FALSE;
                        *comp_enabled =
                            (cp->dce_and_dcc & SA_DCP_DCE)? TRUE : FALSE;
                        *comp_algorithm = scsi_4btoul(cp->comp_algorithm);
                } else {
                        struct scsi_dev_conf_page *cp = &ntcs->dconf;
                        /*
                         * We don't really know whether this device supports
                         * Data Compression if the the algorithm field is
                         * zero. Just say we do.
                         */
                        *comp_supported = TRUE;
                        *comp_enabled =
                            (cp->sel_comp_alg != SA_COMP_NONE)? TRUE : FALSE;
                        *comp_algorithm = cp->sel_comp_alg;
                }
                if (tcs != NULL)
                        bcopy(ntcs, tcs, sizeof (sa_comp_t));
        }

        if (CAM_DEBUGGED(periph->path, CAM_DEBUG_INFO)) {
                int idx;
                char *xyz = mode_buffer;
                xpt_print_path(periph->path);
                kprintf("Mode Sense Data=");
                for (idx = 0; idx < mode_buffer_len; idx++)
                        kprintf(" 0x%02x", xyz[idx] & 0xff);
                kprintf("\n");
        }

sagetparamsexit:

        xpt_release_ccb(ccb);
        kfree(mode_buffer, M_SCSISA);
        return (error);
}

/*
 * The purpose of this function is to set one of four different parameters
 * for a tape drive:
 *      - blocksize
 *      - density
 *      - compression / compression algorithm
 *      - buffering mode
 *
 * The assumption is that this will be called from saioctl(), and therefore
 * from a process context.  Thus the waiting malloc calls below.  If that
 * assumption ever changes, the malloc calls should be changed to be
 * NOWAIT mallocs.
 *
 * Any or all of the four parameters may be set when this function is
 * called.  It should handle setting more than one parameter at once.
 */
static int
sasetparams(struct cam_periph *periph, sa_params params_to_set,
            u_int32_t blocksize, u_int8_t density, u_int32_t calg,
            u_int32_t sense_flags)
{
        struct sa_softc *softc;
        u_int32_t current_blocksize = 0;/* silence gcc */
        u_int32_t current_calg;
        u_int8_t current_density = 0;   /* silence gcc */
        u_int8_t current_speed = 0;     /* silence gcc */
        int comp_enabled, comp_supported;
        void *mode_buffer;
        int mode_buffer_len;
        struct scsi_mode_header_6 *mode_hdr;
        struct scsi_mode_blk_desc *mode_blk;
        sa_comp_t *ccomp, *cpage;
        int buff_mode;
        union ccb *ccb = NULL;
        int error;

        softc = (struct sa_softc *)periph->softc;

        ccomp = kmalloc(sizeof (sa_comp_t), M_SCSISA, M_INTWAIT);

        /*
         * Since it doesn't make sense to set the number of blocks, or
         * write protection, we won't try to get the current value.  We
         * always want to get the blocksize, so we can set it back to the
         * proper value.
         */
        error = sagetparams(periph,
            params_to_set | SA_PARAM_BLOCKSIZE | SA_PARAM_SPEED,
            &current_blocksize, &current_density, NULL, &buff_mode, NULL,
            &current_speed, &comp_supported, &comp_enabled,
            &current_calg, ccomp);

        if (error != 0) {
                kfree(ccomp, M_SCSISA);
                return (error);
        }

        mode_buffer_len = sizeof(*mode_hdr) + sizeof(*mode_blk);
        if (params_to_set & SA_PARAM_COMPRESSION)
                mode_buffer_len += sizeof (sa_comp_t);

        mode_buffer = kmalloc(mode_buffer_len, M_SCSISA, M_INTWAIT | M_ZERO);

        mode_hdr = (struct scsi_mode_header_6 *)mode_buffer;
        mode_blk = (struct scsi_mode_blk_desc *)&mode_hdr[1];

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

retry:

        if (params_to_set & SA_PARAM_COMPRESSION) {
                if (mode_blk) {
                        cpage = (sa_comp_t *)&mode_blk[1];
                } else {
                        cpage = (sa_comp_t *)&mode_hdr[1];
                }
                bcopy(ccomp, cpage, sizeof (sa_comp_t));
                cpage->hdr.pagecode &= ~0x80;
        } else
                cpage = NULL;

        /*
         * If the caller wants us to set the blocksize, use the one they
         * pass in.  Otherwise, use the blocksize we got back from the
         * mode select above.
         */
        if (mode_blk) {
                if (params_to_set & SA_PARAM_BLOCKSIZE)
                        scsi_ulto3b(blocksize, mode_blk->blklen);
                else
                        scsi_ulto3b(current_blocksize, mode_blk->blklen);

                /*
                 * Set density if requested, else preserve old density.
                 * SCSI_SAME_DENSITY only applies to SCSI-2 or better
                 * devices, else density we've latched up in our softc.
                 */
                if (params_to_set & SA_PARAM_DENSITY) {
                        mode_blk->density = density;
                } else if (softc->scsi_rev > SCSI_REV_CCS) {
                        mode_blk->density = SCSI_SAME_DENSITY;
                } else {
                        mode_blk->density = softc->media_density;
                }
        }

        /*
         * For mode selects, these two fields must be zero.
         */
        mode_hdr->data_length = 0;
        mode_hdr->medium_type = 0;

        /* set the speed to the current value */
        mode_hdr->dev_spec = current_speed;

        /* if set, set single-initiator buffering mode */
        if (softc->buffer_mode == SMH_SA_BUF_MODE_SIBUF) {
                mode_hdr->dev_spec |= SMH_SA_BUF_MODE_SIBUF;
        }

        if (mode_blk)
                mode_hdr->blk_desc_len = sizeof(struct scsi_mode_blk_desc);
        else
                mode_hdr->blk_desc_len = 0;

        /*
         * First, if the user wants us to set the compression algorithm or
         * just turn compression on, check to make sure that this drive
         * supports compression.
         */
        if (params_to_set & SA_PARAM_COMPRESSION) {
                /*
                 * If the compression algorithm is 0, disable compression.
                 * If the compression algorithm is non-zero, enable
                 * compression and set the compression type to the
                 * specified compression algorithm, unless the algorithm is
                 * MT_COMP_ENABLE.  In that case, we look at the
                 * compression algorithm that is currently set and if it is
                 * non-zero, we leave it as-is.  If it is zero, and we have
                 * saved a compression algorithm from a time when
                 * compression was enabled before, set the compression to
                 * the saved value.
                 */
                switch (ccomp->hdr.pagecode & ~0x80) {
                case SA_DEVICE_CONFIGURATION_PAGE:
                {
                        struct scsi_dev_conf_page *dcp = &cpage->dconf;
                        if (calg == 0) {
                                dcp->sel_comp_alg = SA_COMP_NONE;
                                break;
                        }
                        if (calg != MT_COMP_ENABLE) {
                                dcp->sel_comp_alg = calg;
                        } else if (dcp->sel_comp_alg == SA_COMP_NONE &&
                            softc->saved_comp_algorithm != 0) {
                                dcp->sel_comp_alg = softc->saved_comp_algorithm;
                        }
                        break;
                }
                case SA_DATA_COMPRESSION_PAGE:
                if (ccomp->dcomp.dce_and_dcc & SA_DCP_DCC) {
                        struct scsi_data_compression_page *dcp = &cpage->dcomp;
                        if (calg == 0) {
                                /*
                                 * Disable compression, but leave the
                                 * decompression and the capability bit
                                 * alone.
                                 */
                                dcp->dce_and_dcc = SA_DCP_DCC;
                                dcp->dde_and_red |= SA_DCP_DDE;
                                break;
                        }
                        /* enable compression && decompression */
                        dcp->dce_and_dcc = SA_DCP_DCE | SA_DCP_DCC;
                        dcp->dde_and_red |= SA_DCP_DDE;
                        /*
                         * If there, use compression algorithm from caller.
                         * Otherwise, if there's a saved compression algorithm
                         * and there is no current algorithm, use the saved
                         * algorithm. Else parrot back what we got and hope
                         * for the best.
                         */
                        if (calg != MT_COMP_ENABLE) {
                                scsi_ulto4b(calg, dcp->comp_algorithm);
                                scsi_ulto4b(calg, dcp->decomp_algorithm);
                        } else if (scsi_4btoul(dcp->comp_algorithm) == 0 &&
                            softc->saved_comp_algorithm != 0) {
                                scsi_ulto4b(softc->saved_comp_algorithm,
                                    dcp->comp_algorithm);
                                scsi_ulto4b(softc->saved_comp_algorithm,
                                    dcp->decomp_algorithm);
                        }
                        break;
                }
                /*
                 * Compression does not appear to be supported-
                 * at least via the DATA COMPRESSION page. It
                 * would be too much to ask us to believe that
                 * the page itself is supported, but incorrectly
                 * reports an ability to manipulate data compression,
                 * so we'll assume that this device doesn't support
                 * compression. We can just fall through for that.
                 */
                /* FALLTHROUGH */
                default:
                        /*
                         * The drive doesn't seem to support compression,
                         * so turn off the set compression bit.
                         */
                        params_to_set &= ~SA_PARAM_COMPRESSION;
                        xpt_print(periph->path,
                            "device does not seem to support compression\n");

                        /*
                         * If that was the only thing the user wanted us to set,
                         * clean up allocated resources and return with
                         * 'operation not supported'.
                         */
                        if (params_to_set == SA_PARAM_NONE) {
                                kfree(mode_buffer, M_SCSISA);
                                xpt_release_ccb(ccb);
                                return (ENODEV);
                        }
                
                        /*
                         * That wasn't the only thing the user wanted us to set.
                         * So, decrease the stated mode buffer length by the
                         * size of the compression mode page.
                         */
                        mode_buffer_len -= sizeof(sa_comp_t);
                }
        }

        /* It is safe to retry this operation */
        scsi_mode_select(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG,
            (params_to_set & SA_PARAM_COMPRESSION)? TRUE : FALSE,
            FALSE, mode_buffer, mode_buffer_len, SSD_FULL_SIZE, SCSIOP_TIMEOUT);

        error = cam_periph_runccb(ccb, saerror, 0,
            sense_flags, &softc->device_stats);
        QFRLS(ccb);

        if (CAM_DEBUGGED(periph->path, CAM_DEBUG_INFO)) {
                int idx;
                char *xyz = mode_buffer;
                xpt_print_path(periph->path);
                kprintf("Err%d, Mode Select Data=", error);
                for (idx = 0; idx < mode_buffer_len; idx++)
                        kprintf(" 0x%02x", xyz[idx] & 0xff);
                kprintf("\n");
        }


        if (error) {
                /*
                 * If we can, try without setting density/blocksize.
                 */
                if (mode_blk) {
                        if ((params_to_set &
                            (SA_PARAM_DENSITY|SA_PARAM_BLOCKSIZE)) == 0) {
                                mode_blk = NULL;
                                goto retry;
                        }
                } else {
                        mode_blk = (struct scsi_mode_blk_desc *)&mode_hdr[1];
                        cpage = (sa_comp_t *)&mode_blk[1];
                }

                /*
                 * If we were setting the blocksize, and that failed, we
                 * want to set it to its original value.  If we weren't
                 * setting the blocksize, we don't want to change it.
                 */
                scsi_ulto3b(current_blocksize, mode_blk->blklen);

                /*
                 * Set density if requested, else preserve old density.
                 * SCSI_SAME_DENSITY only applies to SCSI-2 or better
                 * devices, else density we've latched up in our softc.
                 */
                if (params_to_set & SA_PARAM_DENSITY) {
                        mode_blk->density = current_density;
                } else if (softc->scsi_rev > SCSI_REV_CCS) {
                        mode_blk->density = SCSI_SAME_DENSITY;
                } else {
                        mode_blk->density = softc->media_density;
                }

                if (params_to_set & SA_PARAM_COMPRESSION)
                        bcopy(ccomp, cpage, sizeof (sa_comp_t));

                /*
                 * The retry count is the only CCB field that might have been
                 * changed that we care about, so reset it back to 1.
                 */
                ccb->ccb_h.retry_count = 1;
                cam_periph_runccb(ccb, saerror, 0, sense_flags,
                    &softc->device_stats);
                QFRLS(ccb);
        }

        xpt_release_ccb(ccb);

        if (ccomp != NULL)
                kfree(ccomp, M_SCSISA);

        if (params_to_set & SA_PARAM_COMPRESSION) {
                if (error) {
                        softc->flags &= ~SA_FLAG_COMP_ENABLED;
                        /*
                         * Even if we get an error setting compression,
                         * do not say that we don't support it. We could
                         * have been wrong, or it may be media specific.
                         *      softc->flags &= ~SA_FLAG_COMP_SUPP;
                         */
                        softc->saved_comp_algorithm = softc->comp_algorithm;
                        softc->comp_algorithm = 0;
                } else {
                        softc->flags |= SA_FLAG_COMP_ENABLED;
                        softc->comp_algorithm = calg;
                }
        }

        kfree(mode_buffer, M_SCSISA);
        return (error);
}

static void
saprevent(struct cam_periph *periph, int action)
{
        struct  sa_softc *softc;
        union   ccb *ccb;               
        int     error, sf;
                
        softc = (struct sa_softc *)periph->softc;

        if ((action == PR_ALLOW) && (softc->flags & SA_FLAG_TAPE_LOCKED) == 0)
                return;
        if ((action == PR_PREVENT) && (softc->flags & SA_FLAG_TAPE_LOCKED) != 0)
                return;

        /*
         * We can be quiet about illegal requests.
         */
        if (CAM_DEBUGGED(periph->path, CAM_DEBUG_INFO)) {
                sf = 0;
        } else
                sf = SF_QUIET_IR;

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* It is safe to retry this operation */
        scsi_prevent(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG, action,
            SSD_FULL_SIZE, SCSIOP_TIMEOUT);

        error = cam_periph_runccb(ccb, saerror, 0, sf, &softc->device_stats);
        QFRLS(ccb);
        if (error == 0) {
                if (action == PR_ALLOW)
                        softc->flags &= ~SA_FLAG_TAPE_LOCKED;
                else
                        softc->flags |= SA_FLAG_TAPE_LOCKED;
        }

        xpt_release_ccb(ccb);
}

static int
sarewind(struct cam_periph *periph)
{
        union   ccb *ccb;
        struct  sa_softc *softc;
        int     error;
                
        softc = (struct sa_softc *)periph->softc;

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* It is safe to retry this operation */
        scsi_rewind(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG, FALSE,
            SSD_FULL_SIZE, REWIND_TIMEOUT);

        softc->dsreg = MTIO_DSREG_REW;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;

        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, FALSE);

        xpt_release_ccb(ccb);
        if (error == 0)
                softc->fileno = softc->blkno = (daddr_t) 0;
        else
                softc->fileno = softc->blkno = (daddr_t) -1;
        return (error);
}

static int
saspace(struct cam_periph *periph, int count, scsi_space_code code)
{
        union   ccb *ccb;
        struct  sa_softc *softc;
        int     error;
                
        softc = (struct sa_softc *)periph->softc;

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* This cannot be retried */

        scsi_space(&ccb->csio, 0, sadone, MSG_SIMPLE_Q_TAG, code, count,
            SSD_FULL_SIZE, SPACE_TIMEOUT);

        /*
         * Clear residual because we will be using it.
         */
        softc->last_ctl_resid = 0;

        softc->dsreg = (count < 0)? MTIO_DSREG_REV : MTIO_DSREG_FWD;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;

        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, FALSE);

        xpt_release_ccb(ccb);

        /*
         * If a spacing operation has failed, we need to invalidate
         * this mount.
         *
         * If the spacing operation was setmarks or to end of recorded data,
         * we no longer know our relative position.
         *
         * If the spacing operations was spacing files in reverse, we
         * take account of the residual, but still check against less
         * than zero- if we've gone negative, we must have hit BOT.
         *
         * If the spacing operations was spacing records in reverse and
         * we have a residual, we've either hit BOT or hit a filemark.
         * In the former case, we know our new record number (0). In
         * the latter case, we have absolutely no idea what the real
         * record number is- we've stopped between the end of the last
         * record in the previous file and the filemark that stopped
         * our spacing backwards.
         */
        if (error) {
                softc->fileno = softc->blkno = (daddr_t) -1;
        } else if (code == SS_SETMARKS || code == SS_EOD) {
                softc->fileno = softc->blkno = (daddr_t) -1;
        } else if (code == SS_FILEMARKS && softc->fileno != (daddr_t) -1) {
                softc->fileno += (count - softc->last_ctl_resid);
                if (softc->fileno < 0)  /* we must of hit BOT */
                        softc->fileno = 0;
                softc->blkno = 0;
        } else if (code == SS_BLOCKS && softc->blkno != (daddr_t) -1) {
                softc->blkno += (count - softc->last_ctl_resid);
                if (count < 0) {
                        if (softc->last_ctl_resid || softc->blkno < 0) {
                                if (softc->fileno == 0) {
                                        softc->blkno = 0;
                                } else {
                                        softc->blkno = (daddr_t) -1;
                                }
                        }
                }
        }
        return (error);
}

static int
sawritefilemarks(struct cam_periph *periph, int nmarks, int setmarks)
{
        union   ccb *ccb;
        struct  sa_softc *softc;
        int     error, nwm = 0;

        softc = (struct sa_softc *)periph->softc;
        if (softc->open_rdonly)
                return (EBADF);

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /*
         * Clear residual because we will be using it.
         */
        softc->last_ctl_resid = 0;

        softc->dsreg = MTIO_DSREG_FMK;
        /* this *must* not be retried */
        scsi_write_filemarks(&ccb->csio, 0, sadone, MSG_SIMPLE_Q_TAG,
            FALSE, setmarks, nmarks, SSD_FULL_SIZE, IO_TIMEOUT);
        softc->dsreg = MTIO_DSREG_REST;


        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);

        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, FALSE);

        if (error == 0 && nmarks) {
                struct sa_softc *softc = (struct sa_softc *)periph->softc;
                nwm = nmarks - softc->last_ctl_resid;
                softc->filemarks += nwm;
        }

        xpt_release_ccb(ccb);

        /*
         * Update relative positions (if we're doing that).
         */
        if (error) {
                softc->fileno = softc->blkno = (daddr_t) -1;
        } else if (softc->fileno != (daddr_t) -1) {
                softc->fileno += nwm;
                softc->blkno = 0;
        }
        return (error);
}

static int
sardpos(struct cam_periph *periph, int hard, u_int32_t *blkptr)
{
        struct scsi_tape_position_data loc;
        union ccb *ccb;
        struct sa_softc *softc = (struct sa_softc *)periph->softc;
        int error;

        /*
         * We try and flush any buffered writes here if we were writing
         * and we're trying to get hardware block position. It eats
         * up performance substantially, but I'm wary of drive firmware.
         *
         * I think that *logical* block position is probably okay-
         * but hardware block position might have to wait for data
         * to hit media to be valid. Caveat Emptor.
         */

        if (hard && (softc->flags & SA_FLAG_TAPE_WRITTEN)) {
                error = sawritefilemarks(periph, 0, 0);
                if (error && error != EACCES)
                        return (error);
        }

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);
        scsi_read_position(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG,
                           hard, &loc, SSD_FULL_SIZE, SCSIOP_TIMEOUT);
        softc->dsreg = MTIO_DSREG_RBSY;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;
        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, 0);

        if (error == 0) {
                if (loc.flags & SA_RPOS_UNCERTAIN) {
                        error = EINVAL;         /* nothing is certain */
                } else {
                        *blkptr = scsi_4btoul(loc.firstblk);
                }
        }

        xpt_release_ccb(ccb);
        return (error);
}

static int
sasetpos(struct cam_periph *periph, int hard, u_int32_t *blkptr)
{
        union ccb *ccb;
        struct sa_softc *softc;
        int error;

        /*
         * We used to try and flush any buffered writes here.
         * Now we push this onto user applications to either
         * flush the pending writes themselves (via a zero count
         * WRITE FILEMARKS command) or they can trust their tape
         * drive to do this correctly for them.
         */

        softc = (struct sa_softc *)periph->softc;
        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);
        
        scsi_set_position(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG,
            hard, *blkptr, SSD_FULL_SIZE, SPACE_TIMEOUT);


        softc->dsreg = MTIO_DSREG_POS;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;
        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, 0);
        xpt_release_ccb(ccb);
        /*
         * Note relative file && block number position as now unknown.
         */
        softc->fileno = softc->blkno = (daddr_t) -1;
        return (error);
}

static int
saretension(struct cam_periph *periph)
{
        union ccb *ccb;
        struct sa_softc *softc;
        int error;

        softc = (struct sa_softc *)periph->softc;

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* It is safe to retry this operation */
        scsi_load_unload(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG, FALSE,
            FALSE, TRUE,  TRUE, SSD_FULL_SIZE, ERASE_TIMEOUT);

        softc->dsreg = MTIO_DSREG_TEN;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;

        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, FALSE);
        xpt_release_ccb(ccb);
        if (error == 0)
                softc->fileno = softc->blkno = (daddr_t) 0;
        else
                softc->fileno = softc->blkno = (daddr_t) -1;
        return (error);
}

static int
sareservereleaseunit(struct cam_periph *periph, int reserve)
{
        union ccb *ccb;
        struct sa_softc *softc;
        int error;

        softc = (struct sa_softc *)periph->softc;
        ccb = cam_periph_getccb(periph,  1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* It is safe to retry this operation */
        scsi_reserve_release_unit(&ccb->csio, 2, sadone, MSG_SIMPLE_Q_TAG,
            FALSE,  0, SSD_FULL_SIZE,  SCSIOP_TIMEOUT, reserve);
        softc->dsreg = MTIO_DSREG_RBSY;
        error = cam_periph_runccb(ccb, saerror, 0,
            SF_RETRY_UA | SF_NO_PRINT, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;
        QFRLS(ccb);
        xpt_release_ccb(ccb);

        /*
         * If the error was Illegal Request, then the device doesn't support
         * RESERVE/RELEASE. This is not an error.
         */
        if (error == EINVAL) {
                error = 0;
        }

        return (error);
}

static int
saloadunload(struct cam_periph *periph, int load)
{
        union   ccb *ccb;
        struct  sa_softc *softc;
        int     error;

        softc = (struct sa_softc *)periph->softc;

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        /* It is safe to retry this operation */
        scsi_load_unload(&ccb->csio, 5, sadone, MSG_SIMPLE_Q_TAG, FALSE,
            FALSE, FALSE, load, SSD_FULL_SIZE, REWIND_TIMEOUT);

        softc->dsreg = (load)? MTIO_DSREG_LD : MTIO_DSREG_UNL;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;
        QFRLS(ccb);
        xpt_release_ccb(ccb);

        if (error || load == 0)
                softc->fileno = softc->blkno = (daddr_t) -1;
        else if (error == 0)
                softc->fileno = softc->blkno = (daddr_t) 0;
        return (error);
}

static int
saerase(struct cam_periph *periph, int longerase)
{

        union   ccb *ccb;
        struct  sa_softc *softc;
        int error;

        softc = (struct sa_softc *)periph->softc;
        if (softc->open_rdonly)
                return (EBADF);

        ccb = cam_periph_getccb(periph, 1);
        Set_CCB_Type(ccb, SA_CCB_POLLED);

        scsi_erase(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG, FALSE, longerase,
            SSD_FULL_SIZE, ERASE_TIMEOUT);

        softc->dsreg = MTIO_DSREG_ZER;
        error = cam_periph_runccb(ccb, saerror, 0, 0, &softc->device_stats);
        softc->dsreg = MTIO_DSREG_REST;

        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path, 0, 0, 0, FALSE);
        xpt_release_ccb(ccb);
        return (error);
}

#endif /* _KERNEL */

/*
 * Read tape block limits command.
 */
void
scsi_read_block_limits(struct ccb_scsiio *csio, u_int32_t retries,
                   void (*cbfcnp)(struct cam_periph *, union ccb *),
                   u_int8_t tag_action,
                   struct scsi_read_block_limits_data *rlimit_buf,
                   u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_read_block_limits *scsi_cmd;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_IN, tag_action,
             (u_int8_t *)rlimit_buf, sizeof(*rlimit_buf), sense_len,
             sizeof(*scsi_cmd), timeout);

        scsi_cmd = (struct scsi_read_block_limits *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));
        scsi_cmd->opcode = READ_BLOCK_LIMITS;
}

void
scsi_sa_read_write(struct ccb_scsiio *csio, u_int32_t retries,
                   void (*cbfcnp)(struct cam_periph *, union ccb *),
                   u_int8_t tag_action, int readop, int sli,
                   int fixed, u_int32_t length, u_int8_t *data_ptr,
                   u_int32_t dxfer_len, u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_sa_rw *scsi_cmd;

        scsi_cmd = (struct scsi_sa_rw *)&csio->cdb_io.cdb_bytes;
        scsi_cmd->opcode = readop ? SA_READ : SA_WRITE;
        scsi_cmd->sli_fixed = 0;
        if (sli && readop)
                scsi_cmd->sli_fixed |= SAR_SLI;
        if (fixed)
                scsi_cmd->sli_fixed |= SARW_FIXED;
        scsi_ulto3b(length, scsi_cmd->length);
        scsi_cmd->control = 0;

        cam_fill_csio(csio, retries, cbfcnp, readop ? CAM_DIR_IN : CAM_DIR_OUT,
            tag_action, data_ptr, dxfer_len, sense_len,
            sizeof(*scsi_cmd), timeout);
}

void
scsi_load_unload(struct ccb_scsiio *csio, u_int32_t retries,         
                 void (*cbfcnp)(struct cam_periph *, union ccb *),   
                 u_int8_t tag_action, int immediate, int eot,
                 int reten, int load, u_int8_t sense_len,
                 u_int32_t timeout)
{
        struct scsi_load_unload *scsi_cmd;

        scsi_cmd = (struct scsi_load_unload *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));
        scsi_cmd->opcode = LOAD_UNLOAD;
        if (immediate)
                scsi_cmd->immediate = SLU_IMMED;
        if (eot)
                scsi_cmd->eot_reten_load |= SLU_EOT;
        if (reten)
                scsi_cmd->eot_reten_load |= SLU_RETEN;
        if (load)
                scsi_cmd->eot_reten_load |= SLU_LOAD;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action,
            NULL, 0, sense_len, sizeof(*scsi_cmd), timeout);    
}

void
scsi_rewind(struct ccb_scsiio *csio, u_int32_t retries,         
            void (*cbfcnp)(struct cam_periph *, union ccb *),   
            u_int8_t tag_action, int immediate, u_int8_t sense_len,     
            u_int32_t timeout)
{
        struct scsi_rewind *scsi_cmd;

        scsi_cmd = (struct scsi_rewind *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));
        scsi_cmd->opcode = REWIND;
        if (immediate)
                scsi_cmd->immediate = SREW_IMMED;
        
        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action, NULL,
            0, sense_len, sizeof(*scsi_cmd), timeout);
}

void
scsi_space(struct ccb_scsiio *csio, u_int32_t retries,
           void (*cbfcnp)(struct cam_periph *, union ccb *),
           u_int8_t tag_action, scsi_space_code code,
           u_int32_t count, u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_space *scsi_cmd;

        scsi_cmd = (struct scsi_space *)&csio->cdb_io.cdb_bytes;
        scsi_cmd->opcode = SPACE;
        scsi_cmd->code = code;
        scsi_ulto3b(count, scsi_cmd->count);
        scsi_cmd->control = 0;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action, NULL,
            0, sense_len, sizeof(*scsi_cmd), timeout);
}

void
scsi_write_filemarks(struct ccb_scsiio *csio, u_int32_t retries,
                     void (*cbfcnp)(struct cam_periph *, union ccb *),
                     u_int8_t tag_action, int immediate, int setmark,
                     u_int32_t num_marks, u_int8_t sense_len,
                     u_int32_t timeout)
{
        struct scsi_write_filemarks *scsi_cmd;

        scsi_cmd = (struct scsi_write_filemarks *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));
        scsi_cmd->opcode = WRITE_FILEMARKS;
        if (immediate)
                scsi_cmd->byte2 |= SWFMRK_IMMED;
        if (setmark)
                scsi_cmd->byte2 |= SWFMRK_WSMK;
        
        scsi_ulto3b(num_marks, scsi_cmd->num_marks);

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action, NULL,
            0, sense_len, sizeof(*scsi_cmd), timeout);
}

/*
 * The reserve and release unit commands differ only by their opcodes.
 */
void
scsi_reserve_release_unit(struct ccb_scsiio *csio, u_int32_t retries,
                          void (*cbfcnp)(struct cam_periph *, union ccb *),
                          u_int8_t tag_action, int third_party,
                          int third_party_id, u_int8_t sense_len,
                          u_int32_t timeout, int reserve)
{
        struct scsi_reserve_release_unit *scsi_cmd;

        scsi_cmd = (struct scsi_reserve_release_unit *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));

        if (reserve)
                scsi_cmd->opcode = RESERVE_UNIT;
        else
                scsi_cmd->opcode = RELEASE_UNIT;

        if (third_party) {
                scsi_cmd->lun_thirdparty |= SRRU_3RD_PARTY;
                scsi_cmd->lun_thirdparty |=
                        ((third_party_id << SRRU_3RD_SHAMT) & SRRU_3RD_MASK);
        }

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action, NULL,
            0, sense_len, sizeof(*scsi_cmd), timeout);
}

void
scsi_erase(struct ccb_scsiio *csio, u_int32_t retries,
           void (*cbfcnp)(struct cam_periph *, union ccb *),
           u_int8_t tag_action, int immediate, int long_erase,
           u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_erase *scsi_cmd;

        scsi_cmd = (struct scsi_erase *)&csio->cdb_io.cdb_bytes;
        bzero(scsi_cmd, sizeof(*scsi_cmd));

        scsi_cmd->opcode = ERASE;

        if (immediate)
                scsi_cmd->lun_imm_long |= SE_IMMED;

        if (long_erase)
                scsi_cmd->lun_imm_long |= SE_LONG;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action, NULL,
            0, sense_len, sizeof(*scsi_cmd), timeout);
}

/*
 * Read Tape Position command.
 */
void
scsi_read_position(struct ccb_scsiio *csio, u_int32_t retries,
                   void (*cbfcnp)(struct cam_periph *, union ccb *),
                   u_int8_t tag_action, int hardsoft,
                   struct scsi_tape_position_data *sbp,
                   u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_tape_read_position *scmd;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_IN, tag_action,
            (u_int8_t *)sbp, sizeof (*sbp), sense_len, sizeof(*scmd), timeout);
        scmd = (struct scsi_tape_read_position *)&csio->cdb_io.cdb_bytes;
        bzero(scmd, sizeof(*scmd));
        scmd->opcode = READ_POSITION;
        scmd->byte1 = hardsoft;
}

/*
 * Set Tape Position command.
 */
void
scsi_set_position(struct ccb_scsiio *csio, u_int32_t retries,
                   void (*cbfcnp)(struct cam_periph *, union ccb *),
                   u_int8_t tag_action, int hardsoft, u_int32_t blkno,
                   u_int8_t sense_len, u_int32_t timeout)
{
        struct scsi_tape_locate *scmd;

        cam_fill_csio(csio, retries, cbfcnp, CAM_DIR_NONE, tag_action,
            NULL, 0, sense_len, sizeof(*scmd), timeout);
        scmd = (struct scsi_tape_locate *)&csio->cdb_io.cdb_bytes;
        bzero(scmd, sizeof(*scmd));
        scmd->opcode = LOCATE;
        if (hardsoft)
                scmd->byte1 |= SA_SPOS_BT;
        scsi_ulto4b(blkno, scmd->blkaddr);
}