/*
 * Implementation of SCSI Direct Access Peripheral driver for CAM.
 *
 * Copyright (c) 1997 Justin T. Gibbs.
 * 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.
 *
 * $FreeBSD: src/sys/cam/scsi/scsi_da.c,v 1.42.2.46 2003/10/21 22:18:19 thomas Exp $
 */

#include <sys/param.h>

#ifdef _KERNEL

#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/buf.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <sys/lock.h>
#include <sys/caps.h>
#include <sys/conf.h>
#include <sys/devicestat.h>
#include <sys/disk.h>
#include <sys/dtype.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/cons.h>
#include <sys/proc.h>

#include <sys/buf2.h>

#endif /* _KERNEL */

#ifdef _KERNEL
#include <vm/pmap.h>
#endif

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

#include <sys/camlib.h>
#include "../cam.h"
#include "../cam_ccb.h"
#include "../cam_extend.h"
#include "../cam_periph.h"
#include "../cam_xpt_periph.h"
#include "../cam_sim.h"

#include "scsi_daio.h"
#include "scsi_message.h"

#ifndef _KERNEL 
#include "scsi_da.h"
#endif /* !_KERNEL */

#ifdef _KERNEL
typedef enum {
        DA_STATE_PROBE,
        DA_STATE_PROBE2,
        DA_STATE_NORMAL
} da_state;

typedef enum {
        DA_FLAG_PACK_INVALID    = 0x001,
        DA_FLAG_NEW_PACK        = 0x002,
        DA_FLAG_PACK_LOCKED     = 0x004,
        DA_FLAG_PACK_REMOVABLE  = 0x008,
        DA_FLAG_TAGGED_QUEUING  = 0x010,
        DA_FLAG_RETRY_UA        = 0x080,
        DA_FLAG_OPEN            = 0x100,
        DA_FLAG_SCTX_INIT       = 0x200,
        DA_FLAG_RD_LIMIT        = 0x400,
        DA_FLAG_WR_LIMIT        = 0x800,
        DA_FLAG_CAN_TRIM        = 0x1000,
        DA_FLAG_CAP_MUTE        = 0x2000
} da_flags;

typedef enum {
        DA_Q_NONE               = 0x00,
        DA_Q_NO_SYNC_CACHE      = 0x01,
        DA_Q_NO_6_BYTE          = 0x02,
        DA_Q_NO_PREVENT         = 0x04
} da_quirks;

typedef enum {
        DA_CCB_POLLED           = 0x00,
        DA_CCB_PROBE            = 0x01,
        DA_CCB_PROBE2           = 0x02,
        DA_CCB_BUFFER_IO        = 0x03,
        DA_CCB_WAITING          = 0x04,
        DA_CCB_DUMP             = 0x05,
        DA_CCB_TRIM             = 0x06,
        DA_CCB_TYPE_MASK        = 0x0F,
        DA_CCB_RETRY_UA         = 0x10
} da_ccb_state;

/* Offsets into our private area for storing information */
#define ccb_state       ppriv_field0
#define ccb_bio         ppriv_ptr1

struct disk_params {
        u_int8_t  heads;
        u_int32_t cylinders;
        u_int8_t  secs_per_track;
        u_int32_t secsize;      /* Number of bytes/sector */
        u_int64_t sectors;      /* total number sectors */
};

#define TRIM_MAX_BLOCKS 8
#define TRIM_MAX_RANGES TRIM_MAX_BLOCKS * 64
struct trim_request {
        uint8_t         data[TRIM_MAX_RANGES * 8];
        struct bio      *bios[TRIM_MAX_RANGES];
};

struct da_softc {
        struct   bio_queue_head bio_queue_rd;
        struct   bio_queue_head bio_queue_wr;
        struct   bio_queue_head bio_queue_trim;
        struct   devstat device_stats;
        SLIST_ENTRY(da_softc) links;
        LIST_HEAD(, ccb_hdr) pending_ccbs;
        da_state state;
        da_flags flags; 
        da_quirks quirks;
        int      minimum_cmd_size;
        int      outstanding_cmds_rd;   /* outstanding read requests */
        int      outstanding_cmds_wr;   /* outstanding write requests */
        int      tps_ticks;
        long     tps_rd;                /* read bandwidth exponential/tick */
        long     tps_wr;                /* write bandwidth exponential/tick */
        int      trim_max_ranges;
        int      trim_running;
        int      trim_enabled;
        struct   disk_params params;
        struct   disk disk;
        union    ccb saved_ccb;
        struct task             sysctl_task;
        struct sysctl_ctx_list  sysctl_ctx;
        struct sysctl_oid       *sysctl_tree;
        struct trim_request     trim_req;
};

struct da_quirk_entry {
        struct scsi_inquiry_pattern inq_pat;
        da_quirks quirks;
};

static const char quantum[] = "QUANTUM";
static const char microp[] = "MICROP";

static struct da_quirk_entry da_quirk_table[] =
{
        /* SPI, FC devices */
        {
                /*
                 * Fujitsu M2513A MO drives.
                 * Tested devices: M2513A2 firmware versions 1200 & 1300.
                 * (dip switch selects whether T_DIRECT or T_OPTICAL device)
                 * Reported by: W.Scholten <whs@xs4all.nl>
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "FUJITSU", "M2513A", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /* See above. */
                {T_OPTICAL, SIP_MEDIA_REMOVABLE, "FUJITSU", "M2513A", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * This particular Fujitsu drive doesn't like the
                 * synchronize cache command.
                 * Reported by: Tom Jackson <toj@gorilla.net>
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, "FUJITSU", "M2954*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * This drive doesn't like the synchronize cache command
                 * either.  Reported by: Matthew Jacob <mjacob@feral.com>
                 * in NetBSD PR kern/6027, August 24, 1998.
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, microp, "2217*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * This drive doesn't like the synchronize cache command
                 * either.  Reported by: Hellmuth Michaelis (hm@kts.org)
                 * (PR 8882).
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, microp, "2112*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * Doesn't like the synchronize cache command.
                 * Reported by: Blaz Zupan <blaz@gold.amis.net>
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, "NEC", "D3847*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * Doesn't like the synchronize cache command.
                 * Reported by: Blaz Zupan <blaz@gold.amis.net>
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, quantum, "MAVERICK 540S", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * Doesn't like the synchronize cache command.
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, quantum, "LPS525S", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * Doesn't like the synchronize cache command.
                 * Reported by: walter@pelissero.de
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, quantum, "LPS540S", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * Doesn't work correctly with 6 byte reads/writes.
                 * Returns illegal request, and points to byte 9 of the
                 * 6-byte CDB.
                 * Reported by:  Adam McDougall <bsdx@spawnet.com>
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, quantum, "VIKING 4*", "*"},
                /*quirks*/ DA_Q_NO_6_BYTE
        },
        {
                /* See above. */
                {T_DIRECT, SIP_MEDIA_FIXED, quantum, "VIKING 2*", "*"},
                /*quirks*/ DA_Q_NO_6_BYTE
        },
        {
                /*
                 * Doesn't like the synchronize cache command.
                 * Reported by: walter@pelissero.de
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, "CONNER", "CP3500*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * The CISS RAID controllers do not support SYNC_CACHE
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, "COMPAQ", "RAID*", "*"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        {
                /*
                 * The same goes for the mly(4) controllers
                 */
                {T_DIRECT, SIP_MEDIA_FIXED, "MLY*", "*", "MYLX"},
                /*quirks*/ DA_Q_NO_SYNC_CACHE
        },
        /*
         * USB mass storage devices supported by umass(4)
         *
         * NOTE: USB attachments automatically set DA_Q_NO_SYNC_CACHE so
         *       it does not have to be specified here.
         */
        {
                /*
                 * Creative Nomad MUVO mp3 player (USB)
                 * PR: kern/53094
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "CREATIVE", "NOMAD_MUVO", "*"},
                /*quirks*/ DA_Q_NO_PREVENT
        },
        {
                /*
                 * Sigmatel USB Flash MP3 Player
                 * PR: kern/57046
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "SigmaTel", "MSCN", "*"},
                /*quirks*/ DA_Q_NO_PREVENT
        },
        {
                /*
                 * SEAGRAND NP-900 MP3 Player
                 * PR: kern/64563
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "SEAGRAND", "NP-900*", "*"},
                /*quirks*/ DA_Q_NO_PREVENT
        },
        {
                /*
                 * Creative MUVO Slim mp3 player (USB)
                 * PR: usb/86131
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "CREATIVE", "MuVo Slim",
                "*"}, /*quirks*/ DA_Q_NO_PREVENT
        },
        {
                /*
                 * Philips USB Key Audio KEY013
                 * PR: usb/68412
                 */
                {T_DIRECT, SIP_MEDIA_REMOVABLE, "PHILIPS", "Key*", "*"},
                /*quirks*/ DA_Q_NO_PREVENT
        },
};

static  d_open_t        daopen;
static  d_close_t       daclose;
static  d_strategy_t    dastrategy;
static  d_dump_t        dadump;
static  d_ioctl_t       daioctl;
static  periph_init_t   dainit;
static  void            daasync(void *callback_arg, u_int32_t code,
                                struct cam_path *path, void *arg);
static  int             dacmdsizesysctl(SYSCTL_HANDLER_ARGS);
static  periph_ctor_t   daregister;
static  periph_dtor_t   dacleanup;
static  periph_start_t  dastart;
static  periph_oninv_t  daoninvalidate;
static  void            dadone(struct cam_periph *periph,
                               union ccb *done_ccb);
static  int             daerror(union ccb *ccb, u_int32_t cam_flags,
                                u_int32_t sense_flags);
static void             daprevent(struct cam_periph *periph, int action);
static int              dagetcapacity(struct cam_periph *periph, int ccbflags);
static int              dacheckmedia(struct cam_periph *periph);
static void             dasetgeom(struct cam_periph *periph, uint32_t block_len,
                                  uint64_t maxsector);
static void             daflushbioq(struct bio_queue_head *bioq, int error);
static void             dashutdown(void *arg, int howto);

#ifndef DA_DEFAULT_TIMEOUT
#define DA_DEFAULT_TIMEOUT 60   /* Timeout in seconds */
#endif

#ifndef DA_DEFAULT_RETRY
#define DA_DEFAULT_RETRY        4
#endif

__read_mostly int da_retry_count = DA_DEFAULT_RETRY;
__read_mostly int da_default_timeout = DA_DEFAULT_TIMEOUT;
__read_mostly static int da_balance_enable = 1;
__read_mostly static int da_balance_ratio = 100;        /* read-to-write */
__read_mostly static int da_balance_debug = 0;

SYSCTL_NODE(_kern_cam, OID_AUTO, da, CTLFLAG_RD, 0,
            "CAM Direct Access Disk driver");
SYSCTL_INT(_kern_cam_da, OID_AUTO, retry_count, CTLFLAG_RW,
           &da_retry_count, 0, "Normal I/O retry count");
TUNABLE_INT("kern.cam.da.retry_count", &da_retry_count);
SYSCTL_INT(_kern_cam_da, OID_AUTO, default_timeout, CTLFLAG_RW,
           &da_default_timeout, 0, "Normal I/O timeout (in seconds)");
TUNABLE_INT("kern.cam.da.default_timeout", &da_default_timeout);

SYSCTL_INT(_kern_cam_da, OID_AUTO, balance_enable, CTLFLAG_RW,
           &da_balance_enable, 0, "Enable tps balancing");
SYSCTL_INT(_kern_cam_da, OID_AUTO, balance_ratio, CTLFLAG_RW,
           &da_balance_ratio, 0, "Set read-to-write ratio 100=1:1");
SYSCTL_INT(_kern_cam_da, OID_AUTO, balance_debug, CTLFLAG_RW,
           &da_balance_debug, 0, "Enable tps balance debugging");

static struct periph_driver dadriver =
{
        dainit, "da",
        TAILQ_HEAD_INITIALIZER(dadriver.units), /* generation */ 0
};

PERIPHDRIVER_DECLARE(da, dadriver);

static struct dev_ops da_ops = {
        { "da", 0, D_DISK | D_MPSAFE },
        .d_open =       daopen,
        .d_close =      daclose,
        .d_read =       physread,
        .d_write =      physwrite,
        .d_strategy =   dastrategy,
        .d_dump =       dadump,
        .d_ioctl =      daioctl
};

static struct extend_array *daperiphs;

MALLOC_DEFINE(M_SCSIDA, "scsi_da", "scsi_da buffers");

static int
daioctl(struct dev_ioctl_args *ap)
{       
        int unit;
        int error = 0;  
        struct buf *bp;         
        struct cam_periph *periph;
        int byte_count;

        off_t *del_num = (off_t*)ap->a_data;
        off_t bytes_left;
        off_t bytes_start;              

        cdev_t dev = ap->a_head.a_dev;


        unit = dkunit(dev);
        periph = cam_extend_get(daperiphs, unit);
        if (periph == NULL)
                return(ENXIO);
        
        switch (ap->a_cmd) {
        case DAIOCTRIM:
        {

                bytes_left = del_num[1];
                bytes_start = del_num[0];

                /* TRIM occurs on 512-byte sectors. */
                KKASSERT((bytes_left % 512) == 0);
                KKASSERT((bytes_start% 512) == 0);

                
                /* Break TRIM up into int-sized commands because of b_bcount */
                while(bytes_left) {

                        /* 
                         * Rather than than squezing out more blocks in b_bcount 
                         * and having to break up the TRIM request in da_start(),
                         * we ensure we can always TRIM this many bytes with one 
                         * TRIM command (this happens if the device only 
                         * supports one TRIM block). 
                         *  
                         * With min TRIM blksize of 1, TRIM command free
                         * 4194240 blks(64*65535): each LBA range can address 
                         * 65535 blks and there 64 such ranges in a 512-byte 
                         * block. And, 4194240 * 512 = 0x7FFF8000
                         * 
                         */
                        byte_count = MIN(bytes_left,0x7FFF8000);
                        bp = getnewbuf(0, 0, 0, 1);
                
                        bp->b_cmd = BUF_CMD_FREEBLKS;
                        bp->b_bio1.bio_offset = bytes_start;
                        bp->b_bcount = byte_count;
                        bp->b_bio1.bio_flags |= BIO_SYNC;
                        bp->b_bio1.bio_done = biodone_sync;
                
                        dev_dstrategy(ap->a_head.a_dev, &bp->b_bio1);
                
                        if (biowait(&bp->b_bio1, "TRIM")) {
                                kprintf("Error:%d\n", bp->b_error);
                                brelse(bp);
                                return(bp->b_error ? bp->b_error : EIO);
                        }
                        brelse(bp);
                        bytes_left -= byte_count;
                        bytes_start += byte_count;      
                }
                break;
        }
        default:
                return(EINVAL);
        }       
        
        return(error);
}

static int
daopen(struct dev_open_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct cam_periph *periph;
        struct da_softc *softc;
        struct disk_info info;
        int unit;
        int error;

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

        unit = dkunit(dev);
        periph = cam_extend_get(daperiphs, unit);
        if (periph == NULL) {
                return (ENXIO); 
        }

        if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
                return(ENXIO);
        }

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

        unit = periph->unit_number;
        softc = (struct da_softc *)periph->softc;

        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE,
            ("daopen: dev=%s (unit %d)\n", devtoname(dev),
             unit));

        if ((softc->flags & DA_FLAG_PACK_INVALID) != 0) {
                /* Invalidate our pack information. */
                disk_invalidate(&softc->disk);
                softc->flags &= ~DA_FLAG_PACK_INVALID;
        }

        error = dacheckmedia(periph);
        softc->flags |= DA_FLAG_OPEN;

        if (error == 0) {
                struct ccb_getdev *cgd;

                /* Build disk information structure */
                bzero(&info, sizeof(info));
                info.d_type = DTYPE_SCSI;

                /*
                 * Grab the inquiry data to get the vendor and product names.
                 * Put them in the typename and packname for the label.
                 */
                cgd = &xpt_alloc_ccb()->cgd;
                xpt_setup_ccb(&cgd->ccb_h, periph->path, /*priority*/ 1);
                cgd->ccb_h.func_code = XPT_GDEV_TYPE;
                xpt_action((union ccb *)cgd);
                xpt_free_ccb(&cgd->ccb_h);

                /*
                 * Check to see whether or not the blocksize is set yet.
                 * If it isn't, set it and then clear the blocksize
                 * unavailable flag for the device statistics.
                 */
                if ((softc->device_stats.flags & DEVSTAT_BS_UNAVAILABLE) != 0){
                        softc->device_stats.block_size = softc->params.secsize;
                        softc->device_stats.flags &= ~DEVSTAT_BS_UNAVAILABLE;
                }
        }
        
        if (error == 0) {
                softc->flags &= ~DA_FLAG_CAP_MUTE;
                if ((softc->flags & DA_FLAG_PACK_REMOVABLE) != 0 &&
                    (softc->quirks & DA_Q_NO_PREVENT) == 0)
                        daprevent(periph, PR_PREVENT);
        } else {
                softc->flags |= DA_FLAG_CAP_MUTE;
                softc->flags &= ~DA_FLAG_OPEN;
                cam_periph_release(periph);
        }
        cam_periph_unhold(periph, 1);
        return (error);
}

static int
daclose(struct dev_close_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct  cam_periph *periph;
        struct  da_softc *softc;
        int     unit;
        int     error;

        unit = dkunit(dev);
        periph = cam_extend_get(daperiphs, unit);
        if (periph == NULL)
                return (ENXIO); 

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

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

        if ((softc->quirks & DA_Q_NO_SYNC_CACHE) == 0) {
                union   ccb *ccb;

                ccb = cam_periph_getccb(periph, /*priority*/1);
                ccb->ccb_h.ccb_state = DA_CCB_POLLED;

                scsi_synchronize_cache(&ccb->csio,
                                       /*retries*/1,
                                       /*cbfcnp*/dadone,
                                       MSG_SIMPLE_Q_TAG,
                                       /*begin_lba*/0,/* Cover the whole disk */
                                       /*lb_count*/0,
                                       SSD_FULL_SIZE,
                                       5 * 60 * 1000);

                cam_periph_runccb(ccb, /*error_routine*/NULL, /*cam_flags*/0,
                                  /*sense_flags*/SF_RETRY_UA,
                                  &softc->device_stats);

                if ((ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        if ((ccb->ccb_h.status & CAM_STATUS_MASK) ==
                             CAM_SCSI_STATUS_ERROR) {
                                int asc, ascq;
                                int sense_key, error_code;

                                scsi_extract_sense(&ccb->csio.sense_data,
                                                   &error_code,
                                                   &sense_key, 
                                                   &asc, &ascq);
                                if (sense_key != SSD_KEY_ILLEGAL_REQUEST)
                                        scsi_sense_print(&ccb->csio);
                        } else {
                                xpt_print(periph->path, "Synchronize cache "
                                    "failed, status == 0x%x, scsi status == "
                                    "0x%x\n", ccb->csio.ccb_h.status,
                                    ccb->csio.scsi_status);
                        }
                }

                if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                        cam_release_devq(ccb->ccb_h.path,
                                         /*relsim_flags*/0,
                                         /*reduction*/0,
                                         /*timeout*/0,
                                         /*getcount_only*/0);

                xpt_release_ccb(ccb);

        }

        if ((softc->flags & DA_FLAG_PACK_REMOVABLE) != 0) {
                if ((softc->quirks & DA_Q_NO_PREVENT) == 0)
                        daprevent(periph, PR_ALLOW);
                /*
                 * If we've got removeable media, mark the blocksize as
                 * unavailable, since it could change when new media is
                 * inserted.
                 */
                softc->device_stats.flags |= DEVSTAT_BS_UNAVAILABLE;
        }

        /*
         * Don't compound any ref counting software bugs with more.
         */
        if (softc->flags & DA_FLAG_OPEN) {
                softc->flags &= ~DA_FLAG_OPEN;
                cam_periph_release(periph);
        } else {
                xpt_print(periph->path,
                          "daclose() called on an already closed device!\n");
        }
        cam_periph_unhold(periph, 1);
        return (0);     
}

/*
 * 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
dastrategy(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 da_softc *softc;
        u_int  unit;
        
        unit = dkunit(dev);
        periph = cam_extend_get(daperiphs, unit);
        if (periph == NULL) {
                bp->b_error = ENXIO;
                goto bad;               
        }
        softc = (struct da_softc *)periph->softc;

        cam_periph_lock(periph);

#if 0
        /*
         * check it's not too big a transfer for our adapter
         */
        scsi_minphys(bp, &sd_switch);
#endif

        /*
         * Mask interrupts so that the pack cannot be invalidated until
         * after we are in the queue.  Otherwise, we might not properly
         * clean up one of the buffers.
         */
        
        /*
         * If the device has been made invalid, error out
         */
        if ((softc->flags & DA_FLAG_PACK_INVALID)) {
                cam_periph_unlock(periph);
                bp->b_error = ENXIO;
                goto bad;
        }
        
        /*
         * Place it in the queue of disk activities for this disk
         */
        if (bp->b_cmd == BUF_CMD_WRITE || bp->b_cmd == BUF_CMD_FLUSH)
                bioqdisksort(&softc->bio_queue_wr, bio);
        else if (bp->b_cmd == BUF_CMD_FREEBLKS) 
                bioqdisksort(&softc->bio_queue_trim, bio);
        else
                bioqdisksort(&softc->bio_queue_rd, bio);
        
        /*
         * Schedule ourselves for performing the work.
         */
        xpt_schedule(periph, /* XXX priority */1);
        cam_periph_unlock(periph);

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

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

static int
dadump(struct dev_dump_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        struct      cam_periph *periph;
        struct      da_softc *softc;
        u_int       unit;
        u_int32_t   secsize;
        struct      ccb_scsiio *csio;

        unit = dkunit(dev);
        periph = cam_extend_get(daperiphs, unit);
        if (periph == NULL)
                return (ENXIO);

        softc = (struct da_softc *)periph->softc;
        cam_periph_lock(periph);
        secsize = softc->params.secsize; /* XXX: or ap->a_secsize? */

        if ((softc->flags & DA_FLAG_PACK_INVALID) != 0) {
                cam_periph_unlock(periph);
                return (ENXIO);
        }

        csio = &xpt_alloc_ccb()->csio;

        /*
         * because length == 0 means we are supposed to flush cache, we only
         * try to write something if length > 0.
         */
        if (ap->a_length > 0) {
                xpt_setup_ccb(&csio->ccb_h, periph->path, /*priority*/1);
                csio->ccb_h.flags |= CAM_POLLED;
                csio->ccb_h.ccb_state = DA_CCB_DUMP;
                scsi_read_write(csio,
                                /*retries*/1,
                                dadone,
                                MSG_ORDERED_Q_TAG,
                                /*read*/FALSE,
                                /*byte2*/0,
                                /*minimum_cmd_size*/ softc->minimum_cmd_size,
                                ap->a_offset / secsize,
                                ap->a_length / secsize,
                                /*data_ptr*/(u_int8_t *) ap->a_virtual,
                                /*dxfer_len*/ap->a_length,
                                /*sense_len*/SSD_FULL_SIZE,
                                DA_DEFAULT_TIMEOUT * 1000);             
                xpt_polled_action((union ccb *)csio);

                if ((csio->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        kprintf("Aborting dump due to I/O error.\n");
                        if ((csio->ccb_h.status & CAM_STATUS_MASK) ==
                             CAM_SCSI_STATUS_ERROR)
                                scsi_sense_print(csio);
                        else
                                kprintf("status == 0x%x, scsi status == 0x%x\n",
                                       csio->ccb_h.status, csio->scsi_status);
                        cam_periph_unlock(periph);
                        xpt_free_ccb(&csio->ccb_h);
                        return(EIO);
                }
                goto done;
        }

        /*
         * Sync the disk cache contents to the physical media.
         */
        if ((softc->quirks & DA_Q_NO_SYNC_CACHE) == 0) {

                xpt_setup_ccb(&csio->ccb_h, periph->path, /*priority*/1);
                csio->ccb_h.ccb_state = DA_CCB_DUMP;
                scsi_synchronize_cache(csio,
                                       /*retries*/1,
                                       /*cbfcnp*/dadone,
                                       MSG_SIMPLE_Q_TAG,
                                       /*begin_lba*/0,/* Cover the whole disk */
                                       /*lb_count*/0,
                                       SSD_FULL_SIZE,
                                       5 * 60 * 1000);
                xpt_polled_action((union ccb *)csio);

                if ((csio->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        if ((csio->ccb_h.status & CAM_STATUS_MASK) ==
                             CAM_SCSI_STATUS_ERROR) {
                                int asc, ascq;
                                int sense_key, error_code;

                                scsi_extract_sense(&csio->sense_data,
                                                   &error_code,
                                                   &sense_key, 
                                                   &asc, &ascq);
                                if (sense_key != SSD_KEY_ILLEGAL_REQUEST)
                                        scsi_sense_print(csio);
                        } else {
                                xpt_print(periph->path, "Synchronize cache "
                                    "failed, status == 0x%x, scsi status == "
                                    "0x%x\n",
                                    csio->ccb_h.status, csio->scsi_status);
                        }
                }
        }
done:
        cam_periph_unlock(periph);
        xpt_free_ccb(&csio->ccb_h);

        return (0);
}

static void
dainit(void)
{
        cam_status status;

        /*
         * Create our extend array for storing the devices we attach to.
         */
        daperiphs = cam_extend_new();
        if (daperiphs == NULL) {
                kprintf("da: Failed to alloc extend array!\n");
                return;
        }

        /*
         * Install a global async callback.  This callback will
         * receive async callbacks like "new device found".
         */
        status = xpt_register_async(AC_FOUND_DEVICE, daasync, NULL, NULL);

        if (status != CAM_REQ_CMP) {
                kprintf("da: Failed to attach master async callback "
                       "due to status 0x%x!\n", status);
        } else {
                /* Register our shutdown event handler */
                if ((EVENTHANDLER_REGISTER(shutdown_post_sync, dashutdown, 
                                           NULL, SHUTDOWN_PRI_SECOND)) == NULL)
                        kprintf("%s: shutdown event registration failed!\n",
                            __func__);
        }
}

static void
daoninvalidate(struct cam_periph *periph)
{
        struct da_softc *softc;

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

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

        softc->flags |= DA_FLAG_PACK_INVALID;

        /*
         * Return all queued I/O with ENXIO.
         * XXX Handle any transactions queued to the card
         *     with XPT_ABORT_CCB.
         */
        daflushbioq(&softc->bio_queue_trim, ENXIO);
        daflushbioq(&softc->bio_queue_wr, ENXIO);
        daflushbioq(&softc->bio_queue_rd, ENXIO);
        xpt_print(periph->path, "lost device\n");
}

static void
daflushbioq(struct bio_queue_head *bioq, int error)
{
        struct bio *q_bio;
        struct buf *q_bp;

        while ((q_bio = bioq_first(bioq)) != NULL){
                bioq_remove(bioq, q_bio);
                q_bp = q_bio->bio_buf;
                q_bp->b_resid = q_bp->b_bcount;
                q_bp->b_error = error;
                q_bp->b_flags |= B_ERROR;
                biodone(q_bio);
        }
}

static void
dacleanup(struct cam_periph *periph)
{
        struct da_softc *softc;

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

        devstat_remove_entry(&softc->device_stats);
        cam_extend_release(daperiphs, periph->unit_number);
        xpt_print(periph->path, "removing device entry\n");
        /*
         * If we can't free the sysctl tree, oh well...
         */
        if ((softc->flags & DA_FLAG_SCTX_INIT) != 0
            && sysctl_ctx_free(&softc->sysctl_ctx) != 0) {
                xpt_print(periph->path, "can't remove sysctl context\n");
        }
        periph->softc = NULL;
        if (softc->disk.d_rawdev) {
                cam_periph_unlock(periph);
                disk_destroy(&softc->disk);
                cam_periph_lock(periph);
        }

        kfree(softc, M_DEVBUF);
}

static void
daasync(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_DIRECT
                    && SID_TYPE(&cgd->inq_data) != T_RBC
                    && SID_TYPE(&cgd->inq_data) != T_OPTICAL)
                        break;

                /*
                 * Don't complain if a valid peripheral is already attached.
                 */
                periph = cam_periph_find(cgd->ccb_h.path, "da");
                if (periph && (periph->flags & CAM_PERIPH_INVALID) == 0)
                        break;

                /*
                 * Allocate a peripheral instance for
                 * this device and start the probe
                 * process.
                 */
                status = cam_periph_alloc(daregister, daoninvalidate,
                                          dacleanup, dastart,
                                          "da", CAM_PERIPH_BIO,
                                          cgd->ccb_h.path, daasync,
                                          AC_FOUND_DEVICE, cgd);

                if (status != CAM_REQ_CMP && status != CAM_REQ_INPROG) {
                        kprintf("%s: Unable to attach to new device "
                            "due to status 0x%x\n", __func__, status);
                }
                break;
        }
        case AC_SENT_BDR:
        case AC_BUS_RESET:
        {
                struct da_softc *softc;
                struct ccb_hdr *ccbh;

                softc = (struct da_softc *)periph->softc;
                /*
                 * Don't fail on the expected unit attention
                 * that will occur.
                 */
                softc->flags |= DA_FLAG_RETRY_UA;
                LIST_FOREACH(ccbh, &softc->pending_ccbs, periph_links.le)
                        ccbh->ccb_state |= DA_CCB_RETRY_UA;
                /* FALLTHROUGH*/
        }
        default:
                cam_periph_async(periph, code, path, arg);
                break;
        }
}

static void
dasysctlinit(void *context, int pending)
{
        struct cam_periph *periph;
        struct da_softc *softc;
        char tmpstr[80], tmpstr2[80];

        periph = (struct cam_periph *)context;
        if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
                return;
        }

        softc = (struct da_softc *)periph->softc;
        ksnprintf(tmpstr, sizeof(tmpstr),
                  "CAM DA unit %d", periph->unit_number);
        ksnprintf(tmpstr2, sizeof(tmpstr2),
                  "%d", periph->unit_number);

        sysctl_ctx_free(&softc->sysctl_ctx);
        sysctl_ctx_init(&softc->sysctl_ctx);
        softc->flags |= DA_FLAG_SCTX_INIT;
        softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx,
                SYSCTL_STATIC_CHILDREN(_kern_cam_da), OID_AUTO, tmpstr2,
                CTLFLAG_RD, 0, tmpstr);
        if (softc->sysctl_tree == NULL) {
                kprintf("%s: unable to allocate sysctl tree\n", __func__);
                cam_periph_release(periph);
                return;
        }

        /*
         * Now register the sysctl handler, so the user can the value on
         * the fly.
         */
        SYSCTL_ADD_PROC(&softc->sysctl_ctx,SYSCTL_CHILDREN(softc->sysctl_tree),
                OID_AUTO, "minimum_cmd_size", CTLTYPE_INT | CTLFLAG_RW,
                &softc->minimum_cmd_size, 0, dacmdsizesysctl, "I",
                "Minimum CDB size");

        /* Only create the option if the device supports TRIM */
        if (softc->disk.d_info.d_trimflag) {
                SYSCTL_ADD_INT(&softc->sysctl_ctx, 
                    SYSCTL_CHILDREN(softc->sysctl_tree),
                    OID_AUTO,
                    "trim_enabled",
                    CTLFLAG_RW,
                    &softc->trim_enabled,
                    0,
                    "Enable TRIM for this device (SSD))");
        }

        cam_periph_release(periph);
}

static int
dacmdsizesysctl(SYSCTL_HANDLER_ARGS)
{
        int error, value;

        value = *(int *)arg1;

        error = sysctl_handle_int(oidp, &value, 0, req);

        if ((error != 0)
         || (req->newptr == NULL))
                return (error);

        /*
         * Acceptable values here are 6, 10 or 12, or 16.
         */
        if (value < 6)
                value = 6;
        else if ((value > 6)
              && (value <= 10))
                value = 10;
        else if ((value > 10)
              && (value <= 12))
                value = 12;
        else if (value > 12)
                value = 16;

        *(int *)arg1 = value;

        return (0);
}

static cam_status
daregister(struct cam_periph *periph, void *arg)
{
        struct da_softc *softc;
        struct ccb_pathinq *cpi;
        struct ccb_getdev *cgd;
        char tmpstr[80];
        caddr_t match;

        cgd = (struct ccb_getdev *)arg;
        if (periph == NULL) {
                kprintf("%s: periph was NULL!!\n", __func__);
                return(CAM_REQ_CMP_ERR);
        }

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

        softc = kmalloc(sizeof(*softc), M_DEVBUF, M_INTWAIT | M_ZERO);
        sysctl_ctx_init(&softc->sysctl_ctx);
        LIST_INIT(&softc->pending_ccbs);
        softc->state = DA_STATE_PROBE;
        bioq_init(&softc->bio_queue_trim);
        bioq_init(&softc->bio_queue_rd);
        bioq_init(&softc->bio_queue_wr);
        if (SID_IS_REMOVABLE(&cgd->inq_data))
                softc->flags |= DA_FLAG_PACK_REMOVABLE;
        if ((cgd->inq_data.flags & SID_CmdQue) != 0)
                softc->flags |= DA_FLAG_TAGGED_QUEUING;

        /* Used to get TRIM status from AHCI driver */
        if (cgd->inq_data.vendor_specific1[0] == 1) {
                /*
                 * max number of lba ranges an SSD can handle in a single
                 * TRIM command. vendor_specific1[1] is the num of 512-byte 
                 * blocks the SSD reports that can be passed in a TRIM cmd. 
                 */
                softc->trim_max_ranges =
                   min(cgd->inq_data.vendor_specific1[1] * 64, TRIM_MAX_RANGES);
        }

        periph->softc = softc;
        
        cam_extend_set(daperiphs, periph->unit_number, periph);

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

        if (match != NULL)
                softc->quirks = ((struct da_quirk_entry *)match)->quirks;
        else
                softc->quirks = DA_Q_NONE;

        /*
         * Unconditionally disable the synchronize cache command for
         * usb attachments.  It's just impossible to determine if the
         * device supports it or not and if it doesn't the port can
         * brick.
         */
        if (strncmp(periph->sim->sim_name, "umass", 5) == 0) {
                softc->quirks |= DA_Q_NO_SYNC_CACHE;
        }

        TASK_INIT(&softc->sysctl_task, 0, dasysctlinit, periph);

        /* Check if the SIM does not want 6 byte commands */
        cpi = &xpt_alloc_ccb()->cpi;
        xpt_setup_ccb(&cpi->ccb_h, periph->path, /*priority*/1);
        cpi->ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)cpi);
        if (cpi->ccb_h.status == CAM_REQ_CMP && (cpi->hba_misc & PIM_NO_6_BYTE))
                softc->quirks |= DA_Q_NO_6_BYTE;

        /*
         * RBC devices don't have to support READ(6), only READ(10).
         */
        if (softc->quirks & DA_Q_NO_6_BYTE || SID_TYPE(&cgd->inq_data) == T_RBC)
                softc->minimum_cmd_size = 10;
        else
                softc->minimum_cmd_size = 6;

        /*
         * Load the user's default, if any.
         */
        ksnprintf(tmpstr, sizeof(tmpstr), "kern.cam.da.%d.minimum_cmd_size",
                 periph->unit_number);
        TUNABLE_INT_FETCH(tmpstr, &softc->minimum_cmd_size);

        /*
         * 6, 10, 12, and 16 are the currently permissible values.
         */
        if (softc->minimum_cmd_size < 6)
                softc->minimum_cmd_size = 6;
        else if ((softc->minimum_cmd_size > 6)
              && (softc->minimum_cmd_size <= 10))
                softc->minimum_cmd_size = 10;
        else if ((softc->minimum_cmd_size > 10)
              && (softc->minimum_cmd_size <= 12))
                softc->minimum_cmd_size = 12;
        else if (softc->minimum_cmd_size > 12)
                softc->minimum_cmd_size = 16;

        /*
         * The DA driver supports a blocksize, but
         * we don't know the blocksize until we do 
         * a read capacity.  So, set a flag to
         * indicate that the blocksize is 
         * unavailable right now.  We'll clear the
         * flag as soon as we've done a read capacity.
         */
        devstat_add_entry(&softc->device_stats, "da", 
                          periph->unit_number, 0,
                          DEVSTAT_BS_UNAVAILABLE,
                          SID_TYPE(&cgd->inq_data) | DEVSTAT_TYPE_IF_SCSI,
                          DEVSTAT_PRIORITY_DISK);

        /*
         * Register this media as a disk
         */
        CAM_SIM_UNLOCK(periph->sim);
        disk_create(periph->unit_number, &softc->disk, &da_ops);
        if (cpi->maxio == 0 || cpi->maxio > MAXPHYS)
                softc->disk.d_rawdev->si_iosize_max = MAXPHYS;
        else
                softc->disk.d_rawdev->si_iosize_max = cpi->maxio;
        if (bootverbose) {
                kprintf("%s%d: si_iosize_max:%d\n",
                    periph->periph_name,
                    periph->unit_number,
                    softc->disk.d_rawdev->si_iosize_max);
        }
        CAM_SIM_LOCK(periph->sim);

        /*
         * Add async callbacks for bus reset and
         * bus device reset calls.  I don't bother
         * checking if this fails as, in most cases,
         * the system will function just fine without
         * them and the only alternative would be to
         * not attach the device on failure.
         */
        xpt_register_async(AC_SENT_BDR | AC_BUS_RESET | AC_LOST_DEVICE,
                           daasync, periph, periph->path);

        /*
         * Take an exclusive refcount on the periph while dastart is called
         * to finish the probe.  The reference will be dropped in dadone at
         * the end of probe.
         */
        xpt_free_ccb(&cpi->ccb_h);
        cam_periph_hold(periph, 0);
        xpt_schedule(periph, /*priority*/5);

        return(CAM_REQ_CMP);
}

static void
dastart(struct cam_periph *periph, union ccb *start_ccb)
{
        struct da_softc *softc;

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

        switch (softc->state) {
        case DA_STATE_NORMAL:
        {
                /* Pull a buffer from the queue and get going on it */          
                struct bio *bio;
                struct bio *bio_rd;
                struct bio *bio_wr;
                struct buf *bp;
                u_int8_t tag_code;
                int rd_limit;
                int wr_limit;

                /*
                 * See if there is a buf with work for us to do..
                 */
                bio_rd = bioq_first(&softc->bio_queue_rd);
                bio_wr = bioq_first(&softc->bio_queue_wr);

                if (periph->immediate_priority <= periph->pinfo.priority) {
                        CAM_DEBUG_PRINT(CAM_DEBUG_SUBTRACE,
                                        ("queuing for immediate ccb\n"));
                        start_ccb->ccb_h.ccb_state = DA_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);
                        if (bio_rd || bio_wr) {
                                /*
                                 * Have more work to do, so ensure we stay
                                 * scheduled
                                 */
                                xpt_schedule(periph, /* XXX priority */1);
                        }
                        break;
                }

                /* Run the trim command if not already running */
                if (!softc->trim_running &&
                   (bio = bioq_first(&softc->bio_queue_trim)) != NULL) {
                        struct trim_request *req = &softc->trim_req;
                        struct bio *bio1;
                        int bps = 0, ranges = 0;

                        softc->trim_running = 1;
                        bzero(req, sizeof(*req));
                        bio1 = bio;
                        while (1) {
                                uint64_t lba;
                                int count;

                                bp = bio1->bio_buf;
                                count = bp->b_bcount / softc->params.secsize;
                                lba = bio1->bio_offset/softc->params.secsize;

                                bioq_remove(&softc->bio_queue_trim, bio1);
                                while (count > 0) {
                                        int c = min(count, 0xffff);
                                        int off = ranges * 8;

                                        req->data[off + 0] = lba & 0xff;
                                        req->data[off + 1] = (lba >> 8) & 0xff;
                                        req->data[off + 2] = (lba >> 16) & 0xff;
                                        req->data[off + 3] = (lba >> 24) & 0xff;
                                        req->data[off + 4] = (lba >> 32) & 0xff;
                                        req->data[off + 5] = (lba >> 40) & 0xff;
                                        req->data[off + 6] = c & 0xff;
                                        req->data[off + 7] = (c >> 8) & 0xff;
                                        lba += c;
                                        count -= c;
                                        ranges++;
                                }

                                /* Try to merge multiple TRIM requests */
                                req->bios[bps++] = bio1;
                                bio1 = bioq_first(&softc->bio_queue_trim);
                                if (bio1 == NULL ||
                                    bio1->bio_buf->b_bcount / softc->params.secsize >
                                    (softc->trim_max_ranges - ranges) * 0xffff)
                                        break;
                        }


                        cam_fill_csio(&start_ccb->csio,
                            1/*retries*/,
                            dadone,
                            CAM_DIR_OUT,
                            MSG_SIMPLE_Q_TAG,
                            req->data,
                            ((ranges +63)/64)*512,
                            SSD_FULL_SIZE,
                            sizeof(struct scsi_rw_6),
                            da_default_timeout*2);

                        start_ccb->ccb_h.ccb_state = DA_CCB_TRIM;
                        LIST_INSERT_HEAD(&softc->pending_ccbs,
                            &start_ccb->ccb_h, periph_links.le);
                        start_ccb->csio.ccb_h.func_code = XPT_TRIM;
                        start_ccb->ccb_h.ccb_bio = bio;
                        devstat_start_transaction(&softc->device_stats);
                        xpt_action(start_ccb);
                        xpt_schedule(periph, 1);
                        break;
                }

                /*
                 * Select a read or write buffer to queue.  Limit the number
                 * of tags dedicated to reading or writing, giving reads
                 * precedence.
                 *
                 * Writes to modern hard drives go into the HDs cache and
                 * return completion nearly instantly.  That is until the
                 * cache becomes full.  When the HDs cache becomes full
                 * write commands will begin to stall.  If all available
                 * tags are taken up by writes which saturate the drive
                 * reads will become tag-starved.
                 *
                 * A similar situation can occur with reads.  With many
                 * parallel readers all tags can be taken up by reads
                 * and prevent any writes from draining, even if the HD's
                 * cache is not full.
                 */
                rd_limit = periph->sim->max_tagged_dev_openings * 2 / 3 + 1;
                wr_limit = rd_limit;

                /*
                 * When TPS balancing is enabled we force wr_limit to 0
                 * as necessary to balance the read TPS against the write
                 * TPS.  A lower or higher read:write ratio may be selected
                 * via da_balance_ratio.
                 *
                 * wr_limit forcing stops queueing writes.  This is generally
                 * necessary because devices buffer writes and may starve
                 * reads even when plenty of read tags are available.
                 *
                 * When no reads are being done, normalize tps_rd to avoid
                 * instantly crowbaring the write tps.
                 */
                if (da_balance_enable &&
                    periph->sim->max_tagged_dev_openings >= 8 &&
                    (bio_rd || softc->outstanding_cmds_rd) &&
                    (bio_wr || softc->outstanding_cmds_wr) &&
                    softc->tps_rd * 100 < softc->tps_wr * da_balance_ratio) {
                        wr_limit = 0;
                } else if (bio_rd == NULL && softc->outstanding_cmds_rd == 0 &&
                           softc->tps_rd < softc->tps_wr * 2) {
                        softc->tps_rd += 100;
                }
                if (softc->tps_ticks != ticks) {
                        softc->tps_ticks = ticks;
                        softc->tps_rd = (softc->tps_rd * (hz - 1)) / hz;
                        softc->tps_wr = (softc->tps_wr * (hz - 1)) / hz;
                }

#if 1
                /* DEBUGGING */
                static time_t savets;
                if (da_balance_debug &&
                    time_uptime != savets && (bio_rd || bio_wr ||
                                              softc->outstanding_cmds_rd ||
                                              softc->outstanding_cmds_wr)) {
                        kprintf("softc=%p %d/%d %d/%d tps %ld/%ld\n",
                                softc,
                                softc->outstanding_cmds_rd, rd_limit,
                                softc->outstanding_cmds_wr, wr_limit,
                                softc->tps_rd / 100, softc->tps_wr / 100);
                        savets = time_uptime;
                }
#endif
                if (bio_rd && softc->outstanding_cmds_rd < rd_limit) {
                        bio = bio_rd;
                        bioq_remove(&softc->bio_queue_rd, bio);
                        softc->tps_rd += 100;
                } else if (bio_wr && softc->outstanding_cmds_wr < wr_limit) {
                        bio = bio_wr;
                        bioq_remove(&softc->bio_queue_wr, bio);
                        softc->tps_wr += 100;
                } else {
                        if (bio_rd)
                                softc->flags |= DA_FLAG_RD_LIMIT;
                        if (bio_wr)
                                softc->flags |= DA_FLAG_WR_LIMIT;
                        xpt_release_ccb(start_ccb);
                        break;
                }

                /*
                 * We can queue new work.
                 */
                bp = bio->bio_buf;

                devstat_start_transaction(&softc->device_stats);

                tag_code = MSG_SIMPLE_Q_TAG;

                switch(bp->b_cmd) {
                case BUF_CMD_READ:
                case BUF_CMD_WRITE:
                        /*
                         * Block read/write op
                         */
                        KKASSERT(bio->bio_offset % softc->params.secsize == 0);

                        scsi_read_write(
                                &start_ccb->csio,
                                da_retry_count,         /* retries */
                                dadone,
                                tag_code,
                                (bp->b_cmd == BUF_CMD_READ),
                                0,                      /* byte2 */
                                softc->minimum_cmd_size,
                                bio->bio_offset / softc->params.secsize,
                                bp->b_bcount / softc->params.secsize,
                                bp->b_data,
                                bp->b_bcount,
                                SSD_FULL_SIZE,          /* sense_len */
                                da_default_timeout * 1000
                        );
                        break;
                case BUF_CMD_FLUSH:
                        /*
                         * Silently complete a flush request if the device
                         * cannot handle it.
                         */
                        if (softc->quirks & DA_Q_NO_SYNC_CACHE) {
                                xpt_release_ccb(start_ccb);
                                start_ccb = NULL;
                                devstat_end_transaction_buf(
                                        &softc->device_stats, bp);
                                biodone(bio);
                        } else {
                                scsi_synchronize_cache(
                                        &start_ccb->csio,
                                        1,              /* retries */
                                        dadone,         /* cbfcnp */
                                        MSG_SIMPLE_Q_TAG,
                                        0,              /* lba */
                                        0,              /* count (whole disk) */
                                        SSD_FULL_SIZE,
                                        da_default_timeout*1000 /* timeout */
                                );
                        }
                        break;
                case BUF_CMD_FREEBLKS:
                        if (softc->disk.d_info.d_trimflag & DA_FLAG_CAN_TRIM){
                                start_ccb->csio.ccb_h.func_code = XPT_TRIM;
                                break;
                        }
                default:
                        xpt_release_ccb(start_ccb);
                        start_ccb = NULL;
                        panic("dastart: unrecognized bio cmd %d", bp->b_cmd);
                        break; /* NOT REACHED */
                }

                /*
                 * Block out any asyncronous callbacks
                 * while we touch the pending ccb list.
                 */
                if (start_ccb) {
                        start_ccb->ccb_h.ccb_state = DA_CCB_BUFFER_IO;
                        LIST_INSERT_HEAD(&softc->pending_ccbs,
                                         &start_ccb->ccb_h, periph_links.le);
                        if (bp->b_cmd == BUF_CMD_WRITE ||
                            bp->b_cmd == BUF_CMD_FLUSH) {
                                ++softc->outstanding_cmds_wr;
                        } else {
                                ++softc->outstanding_cmds_rd;
                        }

                        /* We expect a unit attention from this device */
                        if ((softc->flags & DA_FLAG_RETRY_UA) != 0) {
                                start_ccb->ccb_h.ccb_state |= DA_CCB_RETRY_UA;
                                softc->flags &= ~DA_FLAG_RETRY_UA;
                        }

                        start_ccb->ccb_h.ccb_bio = bio;
                        xpt_action(start_ccb);
                }
                
                /*
                 * Be sure we stay scheduled if we have more work to do.
                 */
                if (bioq_first(&softc->bio_queue_rd) ||
                    bioq_first(&softc->bio_queue_wr)) {
                        xpt_schedule(periph, 1);
                }
                break;
        }
        case DA_STATE_PROBE:
        {
                struct ccb_scsiio *csio;
                struct scsi_read_capacity_data *rcap;

                rcap = kmalloc(sizeof(*rcap), M_SCSIDA, M_INTWAIT | M_ZERO);
                csio = &start_ccb->csio;
                scsi_read_capacity(csio,
                                   /*retries*/4,
                                   dadone,
                                   MSG_SIMPLE_Q_TAG,
                                   rcap,
                                   SSD_FULL_SIZE,
                                   /*timeout*/5000);
                start_ccb->ccb_h.ccb_bio = NULL;
                start_ccb->ccb_h.ccb_state = DA_CCB_PROBE;
                xpt_action(start_ccb);
                break;
        }
        case DA_STATE_PROBE2:
        {
                struct ccb_scsiio *csio;
                struct scsi_read_capacity_data_16 *rcaplong;

                rcaplong = kmalloc(sizeof(*rcaplong), M_SCSIDA,
                                   M_INTWAIT | M_ZERO);
                csio = &start_ccb->csio;
                scsi_read_capacity_16(csio,
                                    /*retries*/ 4,
                                    /*cbfcnp*/ dadone,
                                    /*tag_action*/ MSG_SIMPLE_Q_TAG,
                                    /*lba*/ 0,
                                    /*reladr*/ 0,
                                    /*pmi*/ 0,
                                    rcaplong,
                                    /*sense_len*/ SSD_FULL_SIZE,
                                    /*timeout*/ 60000);
                start_ccb->ccb_h.ccb_bio = NULL;
                start_ccb->ccb_h.ccb_state = DA_CCB_PROBE2;
                xpt_action(start_ccb);  
                break;
        }
        }
}

static int
cmd6workaround(union ccb *ccb)
{
        struct scsi_rw_6 cmd6;
        struct scsi_rw_10 *cmd10;
        struct da_softc *softc;
        u_int8_t *cdb;
        int frozen;

        cdb = ccb->csio.cdb_io.cdb_bytes;

        /* Translation only possible if CDB is an array and cmd is R/W6 */
        if ((ccb->ccb_h.flags & CAM_CDB_POINTER) != 0 ||
            (*cdb != READ_6 && *cdb != WRITE_6))
                return 0;

        xpt_print(ccb->ccb_h.path, "READ(6)/WRITE(6) not supported, "
            "increasing minimum_cmd_size to 10.\n");
        softc = (struct da_softc *)xpt_path_periph(ccb->ccb_h.path)->softc;
        softc->minimum_cmd_size = 10;

        bcopy(cdb, &cmd6, sizeof(struct scsi_rw_6));
        cmd10 = (struct scsi_rw_10 *)cdb;
        cmd10->opcode = (cmd6.opcode == READ_6) ? READ_10 : WRITE_10;
        cmd10->byte2 = 0;
        scsi_ulto4b(scsi_3btoul(cmd6.addr), cmd10->addr);
        cmd10->reserved = 0;
        scsi_ulto2b(cmd6.length, cmd10->length);
        cmd10->control = cmd6.control;
        ccb->csio.cdb_len = sizeof(*cmd10);

        /* Requeue request, unfreezing queue if necessary */
        frozen = (ccb->ccb_h.status & CAM_DEV_QFRZN) != 0;
        ccb->ccb_h.status = CAM_REQUEUE_REQ;
        xpt_action(ccb);
        if (frozen) {
                cam_release_devq(ccb->ccb_h.path,
                                 /*relsim_flags*/0,
                                 /*reduction*/0,
                                 /*timeout*/0,
                                 /*getcount_only*/0);
        }
        return (ERESTART);
}

static void
dadone(struct cam_periph *periph, union ccb *done_ccb)
{
        struct da_softc *softc;
        struct ccb_scsiio *csio;
        struct disk_info info;

        softc = (struct da_softc *)periph->softc;
        csio = &done_ccb->csio;
        switch (csio->ccb_h.ccb_state & DA_CCB_TYPE_MASK) {
        case DA_CCB_BUFFER_IO:
        case DA_CCB_TRIM:
        {
                struct buf *bp;
                struct bio *bio;
                int mustsched = 0;

                bio = (struct bio *)done_ccb->ccb_h.ccb_bio;
                bp = bio->bio_buf;
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        int error;
                        int sf;
                        
                        if ((csio->ccb_h.ccb_state & DA_CCB_RETRY_UA) != 0)
                                sf = SF_RETRY_UA;
                        else
                                sf = 0;

                        error = daerror(done_ccb, CAM_RETRY_SELTO, sf);
                        if (error == ERESTART) {
                                /*
                                 * A retry was scheuled, so
                                 * just return.
                                 */
                                return;
                        }
                        if (error != 0) {
                                if (error == ENXIO) {
                                        /*
                                         * Catastrophic error.  Mark our pack as
                                         * invalid.
                                         */
                                        /*
                                         * XXX See if this is really a media
                                         * XXX change first?
                                         */
                                        xpt_print(periph->path,
                                            "Invalidating pack\n");
                                        softc->flags |= DA_FLAG_PACK_INVALID;
                                }

                                /*
                                 * Return all queued write I/O's with EIO
                                 * so the client can retry these I/Os in the
                                 * proper order should it attempt to recover.
                                 *
                                 * Leave read I/O's alone.
                                 */
                                daflushbioq(&softc->bio_queue_wr, EIO);
                                bp->b_error = error;
                                bp->b_resid = bp->b_bcount;
                                bp->b_flags |= B_ERROR;
                        } else {
                                bp->b_resid = csio->resid;
                                bp->b_error = 0;
                                if (bp->b_resid != 0)
                                        bp->b_flags |= B_ERROR;
                        }
                        if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                                cam_release_devq(done_ccb->ccb_h.path,
                                                 /*relsim_flags*/0,
                                                 /*reduction*/0,
                                                 /*timeout*/0,
                                                 /*getcount_only*/0);
                } else {
                        if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                                panic("REQ_CMP with QFRZN");
                        bp->b_resid = csio->resid;
                        if (csio->resid > 0)
                                bp->b_flags |= B_ERROR;
                }

                /*
                 * Schedule the peripheral to pipeline further reads and
                 * writes.  A completed write wakes up more pending writes.
                 * A completed read must wake up on either pending reads
                 * or writes due to TPS balancing.
                 *
                 * Block out any asyncronous callbacks while we touch the
                 * pending ccb list.
                 */
                LIST_REMOVE(&done_ccb->ccb_h, periph_links.le);
                if (bp->b_cmd == BUF_CMD_WRITE || bp->b_cmd == BUF_CMD_FLUSH) {
                        --softc->outstanding_cmds_wr;
                        if (softc->flags & DA_FLAG_WR_LIMIT) {
                                softc->flags &= ~DA_FLAG_WR_LIMIT;
                                mustsched = 1;
                        }
                } else {
                        --softc->outstanding_cmds_rd;
                        if (softc->flags &
                            (DA_FLAG_RD_LIMIT | DA_FLAG_WR_LIMIT)) {
                                softc->flags &=
                                        ~(DA_FLAG_RD_LIMIT | DA_FLAG_WR_LIMIT);
                                mustsched = 1;
                        }
                }

                devstat_end_transaction_buf(&softc->device_stats, bp);
                if ((csio->ccb_h.ccb_state & DA_CCB_TYPE_MASK) ==
                    DA_CCB_TRIM) {
                        struct trim_request *req =
                            (struct trim_request *) csio->data_ptr;
                        int i;

                        for (i = 1; i < softc->trim_max_ranges &&
                            req->bios[i]; i++) {
                                struct bio *bp1 = req->bios[i];

                                bp1->bio_buf->b_resid = bp->b_resid;
                                bp1->bio_buf->b_error = bp->b_error;
                                if (bp->b_flags & B_ERROR)
                                        bp1->bio_buf->b_flags |= B_ERROR;
                                biodone(bp1);
                        }
                        softc->trim_running = 0;
                        biodone(bio);
                        xpt_schedule(periph,1);
                } else
                        biodone(bio);


                if (mustsched)
                        xpt_schedule(periph, /*priority*/1);

                break;
        }
        case DA_CCB_PROBE:
        case DA_CCB_PROBE2:
        {
                struct     scsi_read_capacity_data *rdcap;
                struct     scsi_read_capacity_data_16 *rcaplong;
                char       announce_buf[80];
                int        doinfo = 0;

                rdcap = NULL;
                rcaplong = NULL;
                if (softc->state == DA_STATE_PROBE)
                        rdcap =(struct scsi_read_capacity_data *)csio->data_ptr;
                else
                        rcaplong = (struct scsi_read_capacity_data_16 *)
                                    csio->data_ptr;

                bzero(&info, sizeof(info));
                info.d_type = DTYPE_SCSI;
                info.d_serialno = xpt_path_serialno(periph->path);
                
                if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        struct disk_params *dp;
                        uint32_t block_size;
                        uint64_t maxsector;

                        if (softc->state == DA_STATE_PROBE) {
                                block_size = scsi_4btoul(rdcap->length);
                                maxsector = scsi_4btoul(rdcap->addr);

                                /*
                                 * According to SBC-2, if the standard 10
                                 * byte READ CAPACITY command returns 2^32,
                                 * we should issue the 16 byte version of
                                 * the command, since the device in question
                                 * has more sectors than can be represented
                                 * with the short version of the command.
                                 */
                                if (maxsector == 0xffffffff) {
                                        softc->state = DA_STATE_PROBE2;
                                        kfree(rdcap, M_SCSIDA);
                                        xpt_release_ccb(done_ccb);
                                        xpt_schedule(periph, /*priority*/5);
                                        return;
                                }
                        } else {
                                block_size = scsi_4btoul(rcaplong->length);
                                maxsector = scsi_8btou64(rcaplong->addr);
                        }
                        dasetgeom(periph, block_size, maxsector);
                        dp = &softc->params;
                        ksnprintf(announce_buf, sizeof(announce_buf),
                                "%juMB (%ju %u byte sectors: %dH %dS/T %dC)",
                                (uintmax_t) (((uintmax_t)dp->secsize *
                                dp->sectors) / (1024*1024)),
                                (uintmax_t)dp->sectors,
                                dp->secsize, dp->heads, dp->secs_per_track,
                                dp->cylinders);
                        
                        info.d_media_blksize = softc->params.secsize;
                        info.d_media_blocks = softc->params.sectors;
                        info.d_media_size = 0;
                        info.d_secpertrack = softc->params.secs_per_track;
                        info.d_nheads = softc->params.heads;
                        info.d_ncylinders = softc->params.cylinders;
                        info.d_secpercyl = softc->params.heads *
                                                softc->params.secs_per_track;
                        info.d_serialno = xpt_path_serialno(periph->path);
                        doinfo = 1;
                } else {
                        int     error;

                        announce_buf[0] = '\0';

                        /*
                         * Retry any UNIT ATTENTION type errors.  They
                         * are expected at boot.
                         */
                        error = daerror(done_ccb, CAM_RETRY_SELTO,
                                        SF_RETRY_UA|SF_NO_PRINT);
                        if (error == ERESTART) {
                                /*
                                 * A retry was scheuled, so
                                 * just return.
                                 */
                                return;
                        } else if (error != 0) {
                                struct scsi_sense_data *sense;
                                int asc, ascq;
                                int sense_key, error_code;
                                int have_sense;
                                cam_status status;
                                struct ccb_getdev *cgd;

                                /* Don't wedge this device's queue */
                                status = done_ccb->ccb_h.status;
                                if ((status & CAM_DEV_QFRZN) != 0)
                                        cam_release_devq(done_ccb->ccb_h.path,
                                                         /*relsim_flags*/0,
                                                         /*reduction*/0,
                                                         /*timeout*/0,
                                                         /*getcount_only*/0);

                                cgd = &xpt_alloc_ccb()->cgd;
                                xpt_setup_ccb(&cgd->ccb_h,
                                              done_ccb->ccb_h.path,
                                              /* priority */ 1);
                                cgd->ccb_h.func_code = XPT_GDEV_TYPE;
                                xpt_action((union ccb *)cgd);

                                if (((csio->ccb_h.flags & CAM_SENSE_PHYS) != 0)
                                 || ((csio->ccb_h.flags & CAM_SENSE_PTR) != 0)
                                 || ((status & CAM_AUTOSNS_VALID) == 0))
                                        have_sense = FALSE;
                                else
                                        have_sense = TRUE;

                                if (have_sense) {
                                        sense = &csio->sense_data;
                                        scsi_extract_sense(sense, &error_code,
                                                           &sense_key, 
                                                           &asc, &ascq);
                                }
                                /*
                                 * Attach to anything that claims to be a
                                 * direct access or optical disk device,
                                 * as long as it doesn't return a "Logical
                                 * unit not supported" (0x25) error.
                                 */
                                if ((have_sense) && (asc != 0x25)
                                 && (error_code == SSD_CURRENT_ERROR)) {
                                        const char *sense_key_desc;
                                        const char *asc_desc;

                                        scsi_sense_desc(sense_key, asc, ascq,
                                                        &cgd->inq_data,
                                                        &sense_key_desc,
                                                        &asc_desc);
                                        ksnprintf(announce_buf,
                                            sizeof(announce_buf),
                                                "Attempt to query device "
                                                "size failed: %s, %s",
                                                sense_key_desc,
                                                asc_desc);
                                        info.d_media_blksize = 512;
                                        doinfo = 1;
                                } else {
                                        if (have_sense)
                                                scsi_sense_print(
                                                        &done_ccb->csio);
                                        else {
                                                xpt_print(periph->path,
                                                    "got CAM status %#x\n",
                                                    done_ccb->ccb_h.status);
                                        }

                                        xpt_print(periph->path, "fatal error, "
                                            "failed to attach to device\n");

                                        /*
                                         * Free up resources.
                                         */
                                        cam_periph_invalidate(periph);
                                } 
                                xpt_free_ccb(&cgd->ccb_h);
                        }
                }
                kfree(csio->data_ptr, M_SCSIDA);
                if (announce_buf[0] != '\0')
                        xpt_announce_periph(periph, announce_buf);

                if (softc->trim_max_ranges) {
                        info.d_trimflag |= DA_FLAG_CAN_TRIM;
                        kprintf("%s%d: supports TRIM\n",
                            periph->periph_name,
                            periph->unit_number);
                }
                softc->state = DA_STATE_NORMAL;

                /*
                 * Since our peripheral may be invalidated by an error
                 * above or an external event, we must release our CCB
                 * before releasing the probe lock on the peripheral.
                 * The peripheral will only go away once the last lock
                 * is removed, and we need it around for the CCB release
                 * operation.
                 */
                xpt_release_ccb(done_ccb);
                cam_periph_unhold(periph, 0);
                if (doinfo) {
                        CAM_SIM_UNLOCK(periph->sim);
                        disk_setdiskinfo(&softc->disk, &info);
                        CAM_SIM_LOCK(periph->sim);

                        /*
                         * Create our sysctl variables, now that we know
                         * we have successfully attached.
                         */
                        taskqueue_enqueue(taskqueue_thread[mycpuid],
                                          &softc->sysctl_task);
                }
                return;
        }
        case DA_CCB_WAITING:
        {
                /* Caller will release the CCB */
                wakeup(&done_ccb->ccb_h.cbfcnp);
                return;
        }
        case DA_CCB_DUMP:
                /* No-op.  We're polling */
                return;
        case DA_CCB_POLLED:
                /* Caller releases ccb */
                wakeup(&done_ccb->ccb_h.cbfcnp);
                return;
        default:
                break;
        }
        xpt_release_ccb(done_ccb);
}

static int
daerror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
{
        struct da_softc   *softc;
        struct cam_periph *periph;
        int error;

        periph = xpt_path_periph(ccb->ccb_h.path);
        softc = (struct da_softc *)periph->softc;

        /*
         * Automatically detect devices that do not support
         * READ(6)/WRITE(6) and upgrade to using 10 byte cdbs.
         */
        error = 0;
        if ((ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_INVALID) {
                error = cmd6workaround(ccb);
        } else if (((ccb->ccb_h.status & CAM_STATUS_MASK) ==
                   CAM_SCSI_STATUS_ERROR)
         && (ccb->ccb_h.status & CAM_AUTOSNS_VALID)
         && (ccb->csio.scsi_status == SCSI_STATUS_CHECK_COND)
         && ((ccb->ccb_h.flags & CAM_SENSE_PHYS) == 0)
         && ((ccb->ccb_h.flags & CAM_SENSE_PTR) == 0)) {
                int sense_key, error_code, asc, ascq;

                scsi_extract_sense(&ccb->csio.sense_data,
                                   &error_code, &sense_key, &asc, &ascq);
                if (sense_key == SSD_KEY_ILLEGAL_REQUEST)
                        error = cmd6workaround(ccb);
        }
        if (error == ERESTART)
                return (ERESTART);

        /*
         * XXX
         * Until we have a better way of doing pack validation,
         * don't treat UAs as errors.
         */
        sense_flags |= SF_RETRY_UA;
        return(cam_periph_error(ccb, cam_flags, sense_flags,
                                &softc->saved_ccb));
}

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

        if (((action == PR_ALLOW)
          && (softc->flags & DA_FLAG_PACK_LOCKED) == 0)
         || ((action == PR_PREVENT)
          && (softc->flags & DA_FLAG_PACK_LOCKED) != 0)) {
                return;
        }

        ccb = cam_periph_getccb(periph, /*priority*/1);
        ccb->ccb_h.ccb_state = DA_CCB_POLLED;

        scsi_prevent(&ccb->csio,
                     /*retries*/1,
                     /*cbcfp*/dadone,
                     MSG_SIMPLE_Q_TAG,
                     action,
                     SSD_FULL_SIZE,
                     5000);

        error = cam_periph_runccb(ccb, /*error_routine*/NULL, CAM_RETRY_SELTO,
                                  SF_RETRY_UA, &softc->device_stats);

        if (error == 0) {
                if (action == PR_ALLOW)
                        softc->flags &= ~DA_FLAG_PACK_LOCKED;
                else
                        softc->flags |= DA_FLAG_PACK_LOCKED;
        }

        xpt_release_ccb(ccb);
}

/*
 * Check media on open, e.g. card reader devices which had no initial media.
 */
static int
dacheckmedia(struct cam_periph *periph)
{
        struct disk_params *dp;
        struct da_softc *softc;
        struct disk_info info;
        int error;
        int mute;

        softc = (struct da_softc *)periph->softc;
        dp = &softc->params;

        if (softc->flags & DA_FLAG_CAP_MUTE)    /* additional ccb flags */
                mute = CAM_QUIET;
        else
                mute = 0;

        error = dagetcapacity(periph, mute);

        /*
         * Only reprobe on initial open and if the media is removable.
         *
         * NOTE: If we setdiskinfo() it will take the device probe
         *       a bit of time to probe the slices and partitions,
         *       and mess up booting.  So avoid if nothing has changed.
         *       XXX
         */
        if (softc->flags & DA_FLAG_OPEN)
                return (error);
        if ((softc->flags & DA_FLAG_PACK_REMOVABLE) == 0)
                return (error);

        bzero(&info, sizeof(info));
        info.d_type = DTYPE_SCSI;
        info.d_serialno = xpt_path_serialno(periph->path);

        if (error == 0) {
                CAM_SIM_UNLOCK(periph->sim);
                info.d_media_blksize = softc->params.secsize;
                info.d_media_blocks = softc->params.sectors;
                info.d_media_size = 0;
                info.d_secpertrack = softc->params.secs_per_track;
                info.d_nheads = softc->params.heads;
                info.d_ncylinders = softc->params.cylinders;
                info.d_secpercyl = softc->params.heads *
                                        softc->params.secs_per_track;
                info.d_serialno = xpt_path_serialno(periph->path);
                if (info.d_media_blocks != softc->disk.d_info.d_media_blocks) {
                        kprintf("%s%d: open removable media: "
                                "%juMB (%ju %u byte sectors: %dH %dS/T %dC)\n",
                                periph->periph_name, periph->unit_number,
                                (uintmax_t)(((uintmax_t)dp->secsize *
                                             dp->sectors) / (1024*1024)),
                                (uintmax_t)dp->sectors, dp->secsize,
                                dp->heads, dp->secs_per_track, dp->cylinders);
                        disk_setdiskinfo(&softc->disk, &info);
                }
                CAM_SIM_LOCK(periph->sim);
        } else {
                if (!mute || bootverbose) {
                        kprintf("%s%d: open removable media: "
                                "no media present\n",
                                periph->periph_name, periph->unit_number);
                }
                info.d_media_blksize = 512;
                disk_setdiskinfo(&softc->disk, &info);
        }
        return (error);
}

static int
dagetcapacity(struct cam_periph *periph, int ccbflags)
{
        struct da_softc *softc;
        union ccb *ccb;
        struct scsi_read_capacity_data *rcap;
        struct scsi_read_capacity_data_16 *rcaplong;
        uint32_t block_len;
        uint64_t maxsector;
        int error;
 
        softc = (struct da_softc *)periph->softc;
        block_len = 0;
        maxsector = 0;
        error = 0;
 
        /* Do a read capacity */
        rcap = (struct scsi_read_capacity_data *)kmalloc(sizeof(*rcaplong),
                                                         M_SCSIDA, M_INTWAIT);
                
        ccb = cam_periph_getccb(periph, /*priority*/1);
        ccb->ccb_h.ccb_state = DA_CCB_POLLED;

        scsi_read_capacity(&ccb->csio,
                           /*retries*/4,
                           /*cbfncp*/dadone,
                           MSG_SIMPLE_Q_TAG,
                           rcap,
                           SSD_FULL_SIZE,
                           /*timeout*/60000);
        ccb->ccb_h.ccb_bio = NULL;
        ccb->ccb_h.flags |= ccbflags;
 
        error = cam_periph_runccb(ccb, daerror,
                                  /*cam_flags*/CAM_RETRY_SELTO,
                                  /*sense_flags*/SF_RETRY_UA,
                                  &softc->device_stats);
 
        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path,
                                 /*relsim_flags*/0,
                                 /*reduction*/0,
                                 /*timeout*/0,
                                 /*getcount_only*/0);
 
        if (error == 0) {
                block_len = scsi_4btoul(rcap->length);
                maxsector = scsi_4btoul(rcap->addr);

                if (maxsector != 0xffffffff)
                        goto done;
        } else
                goto done;
 
        rcaplong = (struct scsi_read_capacity_data_16 *)rcap;
 
        scsi_read_capacity_16(&ccb->csio,
                              /*retries*/ 4,
                              /*cbfcnp*/ dadone,
                              /*tag_action*/ MSG_SIMPLE_Q_TAG,
                              /*lba*/ 0,
                              /*reladr*/ 0,
                              /*pmi*/ 0,
                              rcaplong,
                              /*sense_len*/ SSD_FULL_SIZE,
                              /*timeout*/ 60000);
        ccb->ccb_h.ccb_bio = NULL;
 
        error = cam_periph_runccb(ccb, daerror,
                                  /*cam_flags*/CAM_RETRY_SELTO,
                                  /*sense_flags*/SF_RETRY_UA,
                                  &softc->device_stats);
 
        if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                cam_release_devq(ccb->ccb_h.path,
                                 /*relsim_flags*/0,
                                 /*reduction*/0,
                                 /*timeout*/0,
                                 /*getcount_only*/0);
 
        if (error == 0) {
                block_len = scsi_4btoul(rcaplong->length);
                maxsector = scsi_8btou64(rcaplong->addr);
        }

done:

        if (error == 0)
                dasetgeom(periph, block_len, maxsector);
 
        xpt_release_ccb(ccb);
 
        kfree(rcap, M_SCSIDA);
 
        return (error);
}

static void
dasetgeom(struct cam_periph *periph, uint32_t block_len, uint64_t maxsector)
{
        struct ccb_calc_geometry *ccg;
        struct da_softc *softc;
        struct disk_params *dp;

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

        dp = &softc->params;
        dp->secsize = block_len;
        dp->sectors = maxsector + 1;
        /*
         * Have the controller provide us with a geometry
         * for this disk.  The only time the geometry
         * matters is when we boot and the controller
         * is the only one knowledgeable enough to come
         * up with something that will make this a bootable
         * device.
         */
        ccg = &xpt_alloc_ccb()->ccg;
        xpt_setup_ccb(&ccg->ccb_h, periph->path, /*priority*/1);
        ccg->ccb_h.func_code = XPT_CALC_GEOMETRY;
        ccg->block_size = dp->secsize;
        ccg->volume_size = dp->sectors;
        ccg->heads = 0;
        ccg->secs_per_track = 0;
        ccg->cylinders = 0;
        xpt_action((union ccb*)ccg);
        if ((ccg->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                /*
                 * We don't know what went wrong here- but just pick
                 * a geometry so we don't have nasty things like divide
                 * by zero.
                 */
                dp->heads = 255;
                dp->secs_per_track = 255;
                dp->cylinders = dp->sectors / (255 * 255);
                if (dp->cylinders == 0) {
                        dp->cylinders = 1;
                }
        } else {
                dp->heads = ccg->heads;
                dp->secs_per_track = ccg->secs_per_track;
                dp->cylinders = ccg->cylinders;
        }
        xpt_free_ccb(&ccg->ccb_h);
}

/*
 * Step through all DA peripheral drivers, and if the device is still open,
 * sync the disk cache to physical media.
 */
static void
dashutdown(void * arg, int howto)
{
        struct cam_periph *periph;
        struct da_softc *softc;

        TAILQ_FOREACH(periph, &dadriver.units, unit_links) {
                union ccb *ccb;

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

                /*
                 * We only sync the cache if the drive is still open, and
                 * if the drive is capable of it..
                 */
                if (((softc->flags & DA_FLAG_OPEN) == 0)
                 || (softc->quirks & DA_Q_NO_SYNC_CACHE)) {
                        cam_periph_unlock(periph);
                        continue;
                }

                ccb = xpt_alloc_ccb();
                xpt_setup_ccb(&ccb->ccb_h, periph->path, /*priority*/1);

                ccb->ccb_h.ccb_state = DA_CCB_DUMP;
                scsi_synchronize_cache(&ccb->csio,
                                       /*retries*/1,
                                       /*cbfcnp*/dadone,
                                       MSG_SIMPLE_Q_TAG,
                                       /*begin_lba*/0, /* whole disk */
                                       /*lb_count*/0,
                                       SSD_FULL_SIZE,
                                       60 * 60 * 1000);

                xpt_polled_action(ccb);

                if ((ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
                        if (((ccb->ccb_h.status & CAM_STATUS_MASK) ==
                             CAM_SCSI_STATUS_ERROR)
                         && (ccb->csio.scsi_status == SCSI_STATUS_CHECK_COND)){
                                int error_code, sense_key, asc, ascq;

                                scsi_extract_sense(&ccb->csio.sense_data,
                                                   &error_code, &sense_key,
                                                   &asc, &ascq);

                                if (sense_key != SSD_KEY_ILLEGAL_REQUEST)
                                        scsi_sense_print(&ccb->csio);
                        } else {
                                xpt_print(periph->path, "Synchronize "
                                    "cache failed, status == 0x%x, scsi status "
                                    "== 0x%x\n", ccb->ccb_h.status,
                                    ccb->csio.scsi_status);
                        }
                }

                if ((ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                        cam_release_devq(ccb->ccb_h.path,
                                         /*relsim_flags*/0,
                                         /*reduction*/0,
                                         /*timeout*/0,
                                         /*getcount_only*/0);

                cam_periph_unlock(periph);
                xpt_free_ccb(&ccb->ccb_h);
        }
}

#else /* !_KERNEL */

/*
 * XXX This is only left out of the kernel build to silence warnings.  If,
 * for some reason this function is used in the kernel, the ifdefs should
 * be moved so it is included both in the kernel and userland.
 */
void
scsi_format_unit(struct ccb_scsiio *csio, u_int32_t retries,
                 void (*cbfcnp)(struct cam_periph *, union ccb *),
                 u_int8_t tag_action, u_int8_t byte2, u_int16_t ileave,
                 u_int8_t *data_ptr, u_int32_t dxfer_len, u_int8_t sense_len,
                 u_int32_t timeout)
{
        struct scsi_format_unit *scsi_cmd;

        scsi_cmd = (struct scsi_format_unit *)&csio->cdb_io.cdb_bytes;
        scsi_cmd->opcode = FORMAT_UNIT;
        scsi_cmd->byte2 = byte2;
        scsi_ulto2b(ileave, scsi_cmd->interleave);

        cam_fill_csio(csio,
                      retries,
                      cbfcnp,
                      /*flags*/ (dxfer_len > 0) ? CAM_DIR_OUT : CAM_DIR_NONE,
                      tag_action,
                      data_ptr,
                      dxfer_len,
                      sense_len,
                      sizeof(*scsi_cmd),
                      timeout);
}

#endif /* _KERNEL */