common/io/emul64.c

	emul64.c revision 89b43686db1fe9681d80a7cf5662730cb9378cae
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2011 Bayard G. Bell. All rights reserved.
 */


/*
 * SCSA HBA nexus driver that emulates an HBA connected to SCSI target
 * devices (large disks).
 */

#ifdef DEBUG
#define EMUL64DEBUG
#endif

#include <sys/scsi/scsi.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/taskq.h>
#include <sys/disp.h>
#include <sys/types.h>
#include <sys/buf.h>
#include <sys/cpuvar.h>
#include <sys/dklabel.h>

#include <sys/emul64.h>
#include <sys/emul64cmd.h>
#include <sys/emul64var.h>

int emul64_usetaskq = 1;    /* set to zero for debugging */
int emul64debug     = 0;
#ifdef  EMUL64DEBUG
static int emul64_cdb_debug = 0;
#include <sys/debug.h>
#endif

/*
 * cb_ops function prototypes
 */
static int emul64_ioctl(dev_t, int cmd, intptr_t arg, int mode,
            cred_t *credp, int *rvalp);

/*
 * dev_ops functions prototypes
 */
static int emul64_info(dev_info_t *dip, ddi_info_cmd_t infocmd,
    void *arg, void **result);
static int emul64_attach(dev_info_t *dip, ddi_attach_cmd_t cmd);
static int emul64_detach(dev_info_t *dip, ddi_detach_cmd_t cmd);

/*
 * Function prototypes
 *
 * SCSA functions exported by means of the transport table
 */
static int emul64_tran_tgt_init(dev_info_t *hba_dip, dev_info_t *tgt_dip,
    scsi_hba_tran_t *tran, struct scsi_device *sd);
static int emul64_scsi_start(struct scsi_address *ap, struct scsi_pkt *pkt);
static void emul64_pkt_comp(void *);
static int emul64_scsi_abort(struct scsi_address *ap, struct scsi_pkt *pkt);
static int emul64_scsi_reset(struct scsi_address *ap, int level);
static int emul64_scsi_getcap(struct scsi_address *ap, char *cap, int whom);
static int emul64_scsi_setcap(struct scsi_address *ap, char *cap, int value,
    int whom);
static struct scsi_pkt *emul64_scsi_init_pkt(struct scsi_address *ap,
    struct scsi_pkt *pkt, struct buf *bp, int cmdlen, int statuslen,
    int tgtlen, int flags, int (*callback)(), caddr_t arg);
static void emul64_scsi_destroy_pkt(struct scsi_address *ap,
                    struct scsi_pkt *pkt);
static void emul64_scsi_dmafree(struct scsi_address *ap, struct scsi_pkt *pkt);
static void emul64_scsi_sync_pkt(struct scsi_address *ap, struct scsi_pkt *pkt);
static int emul64_scsi_reset_notify(struct scsi_address *ap, int flag,
    void (*callback)(caddr_t), caddr_t arg);

/*
 * internal functions
 */
static void emul64_i_initcap(struct emul64 *emul64);

static void emul64_i_log(struct emul64 *emul64, int level, char *fmt, ...);
static int emul64_get_tgtrange(struct emul64 *,
                intptr_t,
                emul64_tgt_t **,
                emul64_tgt_range_t *);
static int emul64_write_off(struct emul64 *,
                emul64_tgt_t *,
                emul64_tgt_range_t *);
static int emul64_write_on(struct emul64 *,
                emul64_tgt_t *,
                emul64_tgt_range_t *);
static emul64_nowrite_t *emul64_nowrite_alloc(emul64_range_t *);
static void emul64_nowrite_free(emul64_nowrite_t *);
static emul64_nowrite_t *emul64_find_nowrite(emul64_tgt_t *,
                    diskaddr_t start_block,
                    size_t blkcnt,
                    emul64_rng_overlap_t *overlapp,
                    emul64_nowrite_t ***prevp);

extern emul64_tgt_t *find_tgt(struct emul64 *, ushort_t, ushort_t);

#ifdef EMUL64DEBUG
static void emul64_debug_dump_cdb(struct scsi_address *ap,
        struct scsi_pkt *pkt);
#endif


#ifdef  _DDICT
static int  ddi_in_panic(void);
static int  ddi_in_panic() { return (0); }
#ifndef SCSI_CAP_RESET_NOTIFICATION
#define SCSI_CAP_RESET_NOTIFICATION     14
#endif
#ifndef SCSI_RESET_NOTIFY
#define SCSI_RESET_NOTIFY           0x01
#endif
#ifndef SCSI_RESET_CANCEL
#define SCSI_RESET_CANCEL           0x02
#endif
#endif

/*
 * Tunables:
 *
 * emul64_max_task
 *  The taskq facility is used to queue up SCSI start requests on a per
 *  controller basis.  If the maximum number of queued tasks is hit,
 *  taskq_ent_alloc() delays for a second, which adversely impacts our
 *  performance.  This value establishes the maximum number of task
 *  queue entries when taskq_create is called.
 *
 * emul64_task_nthreads
 *  Specifies the number of threads that should be used to process a
 *  controller's task queue.  Our init function sets this to the number
 *  of CPUs on the system, but this can be overridden in emul64.conf.
 */
int emul64_max_task = 16;
int emul64_task_nthreads = 1;

/*
 * Local static data
 */
static void     *emul64_state = NULL;

/*
 * Character/block operations.
 */
static struct cb_ops emul64_cbops = {
    scsi_hba_open,      /* cb_open */
    scsi_hba_close,     /* cb_close */
    nodev,          /* cb_strategy */
    nodev,          /* cb_print */
    nodev,          /* cb_dump */
    nodev,          /* cb_read */
    nodev,          /* cb_write */
    emul64_ioctl,       /* cb_ioctl */
    nodev,          /* cb_devmap */
    nodev,          /* cb_mmap */
    nodev,          /* cb_segmap */
    nochpoll,       /* cb_chpoll */
    ddi_prop_op,        /* cb_prop_op */
    NULL,           /* cb_str */
    D_MP | D_64BIT | D_HOTPLUG, /* cb_flag */
    CB_REV,         /* cb_rev */
    nodev,          /* cb_aread */
    nodev           /* cb_awrite */
};

/*
 * autoconfiguration routines.
 */

static struct dev_ops emul64_ops = {
    DEVO_REV,           /* rev, */
    0,              /* refcnt */
    emul64_info,            /* getinfo */
    nulldev,            /* identify */
    nulldev,            /* probe */
    emul64_attach,          /* attach */
    emul64_detach,          /* detach */
    nodev,              /* reset */
    &emul64_cbops,          /* char/block ops */
    NULL,               /* bus ops */
    NULL,               /* power */
    ddi_quiesce_not_needed,         /* quiesce */
};

static struct modldrv modldrv = {
    &mod_driverops,         /* module type - driver */
    "emul64 SCSI Host Bus Adapter", /* module name */
    &emul64_ops,            /* driver ops */
};

static struct modlinkage modlinkage = {
    MODREV_1,           /* ml_rev - must be MODREV_1 */
    &modldrv,           /* ml_linkage */
    NULL                /* end of driver linkage */
};

int
_init(void)
{
    int ret;

    ret = ddi_soft_state_init(&emul64_state, sizeof (struct emul64),
        EMUL64_INITIAL_SOFT_SPACE);
    if (ret != 0)
        return (ret);

    if ((ret = scsi_hba_init(&modlinkage)) != 0) {
        ddi_soft_state_fini(&emul64_state);
        return (ret);
    }

    /* Set the number of task threads to the number of CPUs */
    if (boot_max_ncpus == -1) {
        emul64_task_nthreads = max_ncpus;
    } else {
        emul64_task_nthreads = boot_max_ncpus;
    }

    emul64_bsd_init();

    ret = mod_install(&modlinkage);
    if (ret != 0) {
        emul64_bsd_fini();
        scsi_hba_fini(&modlinkage);
        ddi_soft_state_fini(&emul64_state);
    }

    return (ret);
}

int
_fini(void)
{
    int ret;

    if ((ret = mod_remove(&modlinkage)) != 0)
        return (ret);

    emul64_bsd_fini();

    scsi_hba_fini(&modlinkage);

    ddi_soft_state_fini(&emul64_state);

    return (ret);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

/*
 * Given the device number return the devinfo pointer
 * from the scsi_device structure.
 */
/*ARGSUSED*/
static int
emul64_info(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg, void **result)
{
    struct emul64   *foo;
    int     instance = getminor((dev_t)arg);

    switch (cmd) {
    case DDI_INFO_DEVT2DEVINFO:
        foo = ddi_get_soft_state(emul64_state, instance);
        if (foo != NULL)
            *result = (void *)foo->emul64_dip;
        else {
            *result = NULL;
            return (DDI_FAILURE);
        }
        break;

    case DDI_INFO_DEVT2INSTANCE:
        *result = (void *)(uintptr_t)instance;
        break;

    default:
        return (DDI_FAILURE);
    }

    return (DDI_SUCCESS);
}

/*
 * Attach an instance of an emul64 host adapter.  Allocate data structures,
 * initialize the emul64 and we're on the air.
 */
/*ARGSUSED*/
static int
emul64_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
    int     mutex_initted = 0;
    struct emul64   *emul64;
    int     instance;
    scsi_hba_tran_t *tran = NULL;
    ddi_dma_attr_t  tmp_dma_attr;

    emul64_bsd_get_props(dip);

    bzero((void *) &tmp_dma_attr, sizeof (tmp_dma_attr));
    instance = ddi_get_instance(dip);

    switch (cmd) {
    case DDI_ATTACH:
        break;

    case DDI_RESUME:
        tran = (scsi_hba_tran_t *)ddi_get_driver_private(dip);
        if (!tran) {
            return (DDI_FAILURE);
        }
        emul64 = TRAN2EMUL64(tran);

        return (DDI_SUCCESS);

    default:
        emul64_i_log(NULL, CE_WARN,
            "emul64%d: Cmd != DDI_ATTACH/DDI_RESUME", instance);
        return (DDI_FAILURE);
    }

    /*
     * Allocate emul64 data structure.
     */
    if (ddi_soft_state_zalloc(emul64_state, instance) != DDI_SUCCESS) {
        emul64_i_log(NULL, CE_WARN,
            "emul64%d: Failed to alloc soft state",
            instance);
        return (DDI_FAILURE);
    }

    emul64 = (struct emul64 *)ddi_get_soft_state(emul64_state, instance);
    if (emul64 == (struct emul64 *)NULL) {
        emul64_i_log(NULL, CE_WARN, "emul64%d: Bad soft state",
            instance);
        ddi_soft_state_free(emul64_state, instance);
        return (DDI_FAILURE);
    }


    /*
     * Allocate a transport structure
     */
    tran = scsi_hba_tran_alloc(dip, SCSI_HBA_CANSLEEP);
    if (tran == NULL) {
        cmn_err(CE_WARN, "emul64: scsi_hba_tran_alloc failed\n");
        goto fail;
    }

    emul64->emul64_tran         = tran;
    emul64->emul64_dip          = dip;

    tran->tran_hba_private      = emul64;
    tran->tran_tgt_private      = NULL;
    tran->tran_tgt_init     = emul64_tran_tgt_init;
    tran->tran_tgt_probe        = scsi_hba_probe;
    tran->tran_tgt_free     = NULL;

    tran->tran_start        = emul64_scsi_start;
    tran->tran_abort        = emul64_scsi_abort;
    tran->tran_reset        = emul64_scsi_reset;
    tran->tran_getcap       = emul64_scsi_getcap;
    tran->tran_setcap       = emul64_scsi_setcap;
    tran->tran_init_pkt     = emul64_scsi_init_pkt;
    tran->tran_destroy_pkt      = emul64_scsi_destroy_pkt;
    tran->tran_dmafree      = emul64_scsi_dmafree;
    tran->tran_sync_pkt     = emul64_scsi_sync_pkt;
    tran->tran_reset_notify     = emul64_scsi_reset_notify;

    tmp_dma_attr.dma_attr_minxfer = 0x1;
    tmp_dma_attr.dma_attr_burstsizes = 0x7f;

    /*
     * Attach this instance of the hba
     */
    if (scsi_hba_attach_setup(dip, &tmp_dma_attr, tran,
        0) != DDI_SUCCESS) {
        cmn_err(CE_WARN, "emul64: scsi_hba_attach failed\n");
        goto fail;
    }

    emul64->emul64_initiator_id = 2;

    /*
     * Look up the scsi-options property
     */
    emul64->emul64_scsi_options =
        ddi_prop_get_int(DDI_DEV_T_ANY, dip, 0, "scsi-options",
        EMUL64_DEFAULT_SCSI_OPTIONS);
    EMUL64_DEBUG(emul64, SCSI_DEBUG, "emul64 scsi-options=%x",
        emul64->emul64_scsi_options);


    /* mutexes to protect the emul64 request and response queue */
    mutex_init(EMUL64_REQ_MUTEX(emul64), NULL, MUTEX_DRIVER,
        emul64->emul64_iblock);
    mutex_init(EMUL64_RESP_MUTEX(emul64), NULL, MUTEX_DRIVER,
        emul64->emul64_iblock);

    mutex_initted = 1;

    EMUL64_MUTEX_ENTER(emul64);

    /*
     * Initialize the default Target Capabilities and Sync Rates
     */
    emul64_i_initcap(emul64);

    EMUL64_MUTEX_EXIT(emul64);


    ddi_report_dev(dip);
    emul64->emul64_taskq = taskq_create("emul64_comp",
        emul64_task_nthreads, MINCLSYSPRI, 1, emul64_max_task, 0);

    return (DDI_SUCCESS);

fail:
    emul64_i_log(NULL, CE_WARN, "emul64%d: Unable to attach", instance);

    if (mutex_initted) {
        mutex_destroy(EMUL64_REQ_MUTEX(emul64));
        mutex_destroy(EMUL64_RESP_MUTEX(emul64));
    }
    if (tran) {
        scsi_hba_tran_free(tran);
    }
    ddi_soft_state_free(emul64_state, instance);
    return (DDI_FAILURE);
}

/*ARGSUSED*/
static int
emul64_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
    struct emul64   *emul64;
    scsi_hba_tran_t *tran;
    int     instance = ddi_get_instance(dip);


    /* get transport structure pointer from the dip */
    if (!(tran = (scsi_hba_tran_t *)ddi_get_driver_private(dip))) {
        return (DDI_FAILURE);
    }

    /* get soft state from transport structure */
    emul64 = TRAN2EMUL64(tran);

    if (!emul64) {
        return (DDI_FAILURE);
    }

    EMUL64_DEBUG(emul64, SCSI_DEBUG, "emul64_detach: cmd = %d", cmd);

    switch (cmd) {
    case DDI_DETACH:
        EMUL64_MUTEX_ENTER(emul64);

        taskq_destroy(emul64->emul64_taskq);
        (void) scsi_hba_detach(dip);

        scsi_hba_tran_free(emul64->emul64_tran);


        EMUL64_MUTEX_EXIT(emul64);

        mutex_destroy(EMUL64_REQ_MUTEX(emul64));
        mutex_destroy(EMUL64_RESP_MUTEX(emul64));


        EMUL64_DEBUG(emul64, SCSI_DEBUG, "emul64_detach: done");
        ddi_soft_state_free(emul64_state, instance);

        return (DDI_SUCCESS);

    case DDI_SUSPEND:
        return (DDI_SUCCESS);

    default:
        return (DDI_FAILURE);
    }
}

/*
 * Function name : emul64_tran_tgt_init
 *
 * Return Values : DDI_SUCCESS if target supported, DDI_FAILURE otherwise
 *
 */
/*ARGSUSED*/
static int
emul64_tran_tgt_init(dev_info_t *hba_dip, dev_info_t *tgt_dip,
    scsi_hba_tran_t *tran, struct scsi_device *sd)
{
    struct emul64   *emul64;
    emul64_tgt_t    *tgt;
    char        **geo_vidpid = NULL;
    char        *geo, *vidpid;
    uint32_t    *geoip = NULL;
    uint_t      length;
    uint_t      length2;
    lldaddr_t   sector_count;
    char        prop_name[15];
    int     ret = DDI_FAILURE;

    emul64 = TRAN2EMUL64(tran);
    EMUL64_MUTEX_ENTER(emul64);

    /*
     * We get called for each target driver.conf node, multiple
     * nodes may map to the same tgt,lun (sd.conf, st.conf, etc).
     * Check to see if transport to tgt,lun already established.
     */
    tgt = find_tgt(emul64, sd->sd_address.a_target, sd->sd_address.a_lun);
    if (tgt) {
        ret = DDI_SUCCESS;
        goto out;
    }

    /* see if we have driver.conf specified device for this target,lun */
    (void) snprintf(prop_name, sizeof (prop_name), "targ_%d_%d",
        sd->sd_address.a_target, sd->sd_address.a_lun);
    if (ddi_prop_lookup_string_array(DDI_DEV_T_ANY, hba_dip,
        DDI_PROP_DONTPASS, prop_name,
        &geo_vidpid, &length) != DDI_PROP_SUCCESS)
        goto out;
    if (length < 2) {
        cmn_err(CE_WARN, "emul64: %s property does not have 2 "
            "elements", prop_name);
        goto out;
    }

    /* pick geometry name and vidpid string from string array */
    geo = *geo_vidpid;
    vidpid = *(geo_vidpid + 1);

    /* lookup geometry property integer array */
    if (ddi_prop_lookup_int_array(DDI_DEV_T_ANY, hba_dip, DDI_PROP_DONTPASS,
        geo, (int **)&geoip, &length2) != DDI_PROP_SUCCESS) {
        cmn_err(CE_WARN, "emul64: didn't get prop '%s'", geo);
        goto out;
    }
    if (length2 < 6) {
        cmn_err(CE_WARN, "emul64: property %s does not have 6 "
            "elements", *geo_vidpid);
        goto out;
    }

    /* allocate and initialize tgt structure for tgt,lun */
    tgt = kmem_zalloc(sizeof (emul64_tgt_t), KM_SLEEP);
    rw_init(&tgt->emul64_tgt_nw_lock, NULL, RW_DRIVER, NULL);
    mutex_init(&tgt->emul64_tgt_blk_lock, NULL, MUTEX_DRIVER, NULL);

    /* create avl for data block storage */
    avl_create(&tgt->emul64_tgt_data, emul64_bsd_blkcompare,
        sizeof (blklist_t), offsetof(blklist_t, bl_node));

    /* save scsi_address and vidpid */
    bcopy(sd, &tgt->emul64_tgt_saddr, sizeof (struct scsi_address));
    (void) strncpy(tgt->emul64_tgt_inq, vidpid,
        sizeof (emul64->emul64_tgt->emul64_tgt_inq));

    /*
     * The high order 4 bytes of the sector count always come first in
     * emul64.conf.  They are followed by the low order 4 bytes.  Not
     * all CPU types want them in this order, but laddr_t takes care of
     * this for us.  We then pick up geometry (ncyl X nheads X nsect).
     */
    sector_count._p._u  = *(geoip + 0);
    sector_count._p._l  = *(geoip + 1);
    /*
     * On 32-bit platforms, fix block size if it's greater than the
     * allowable maximum.
     */
#if !defined(_LP64)
    if (sector_count._f > DK_MAX_BLOCKS)
        sector_count._f = DK_MAX_BLOCKS;
#endif
    tgt->emul64_tgt_sectors = sector_count._f;
    tgt->emul64_tgt_dtype   = *(geoip + 2);
    tgt->emul64_tgt_ncyls   = *(geoip + 3);
    tgt->emul64_tgt_nheads  = *(geoip + 4);
    tgt->emul64_tgt_nsect   = *(geoip + 5);

    /* insert target structure into list */
    tgt->emul64_tgt_next = emul64->emul64_tgt;
    emul64->emul64_tgt = tgt;
    ret = DDI_SUCCESS;

out:    EMUL64_MUTEX_EXIT(emul64);
    if (geoip)
        ddi_prop_free(geoip);
    if (geo_vidpid)
        ddi_prop_free(geo_vidpid);
    return (ret);
}

/*
 * Function name : emul64_i_initcap
 *
 * Return Values : NONE
 * Description   : Initializes the default target capabilities and
 *         Sync Rates.
 *
 * Context   : Called from the user thread through attach.
 *
 */
static void
emul64_i_initcap(struct emul64 *emul64)
{
    uint16_t    cap, synch;
    int     i;

    cap = 0;
    synch = 0;
    for (i = 0; i < NTARGETS_WIDE; i++) {
        emul64->emul64_cap[i] = cap;
        emul64->emul64_synch[i] = synch;
    }
    EMUL64_DEBUG(emul64, SCSI_DEBUG, "default cap = 0x%x", cap);
}

/*
 * Function name : emul64_scsi_getcap()
 *
 * Return Values : current value of capability, if defined
 *         -1 if capability is not defined
 * Description   : returns current capability value
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
static int
emul64_scsi_getcap(struct scsi_address *ap, char *cap, int whom)
{
    struct emul64   *emul64 = ADDR2EMUL64(ap);
    int     rval = 0;

    /*
     * We don't allow inquiring about capabilities for other targets
     */
    if (cap == NULL || whom == 0) {
        return (-1);
    }

    EMUL64_MUTEX_ENTER(emul64);

    switch (scsi_hba_lookup_capstr(cap)) {
    case SCSI_CAP_DMA_MAX:
        rval = 1 << 24; /* Limit to 16MB max transfer */
        break;
    case SCSI_CAP_MSG_OUT:
        rval = 1;
        break;
    case SCSI_CAP_DISCONNECT:
        rval = 1;
        break;
    case SCSI_CAP_SYNCHRONOUS:
        rval = 1;
        break;
    case SCSI_CAP_WIDE_XFER:
        rval = 1;
        break;
    case SCSI_CAP_TAGGED_QING:
        rval = 1;
        break;
    case SCSI_CAP_UNTAGGED_QING:
        rval = 1;
        break;
    case SCSI_CAP_PARITY:
        rval = 1;
        break;
    case SCSI_CAP_INITIATOR_ID:
        rval = emul64->emul64_initiator_id;
        break;
    case SCSI_CAP_ARQ:
        rval = 1;
        break;
    case SCSI_CAP_LINKED_CMDS:
        break;
    case SCSI_CAP_RESET_NOTIFICATION:
        rval = 1;
        break;

    default:
        rval = -1;
        break;
    }

    EMUL64_MUTEX_EXIT(emul64);

    return (rval);
}

/*
 * Function name : emul64_scsi_setcap()
 *
 * Return Values : 1 - capability exists and can be set to new value
 *         0 - capability could not be set to new value
 *        -1 - no such capability
 *
 * Description   : sets a capability for a target
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
static int
emul64_scsi_setcap(struct scsi_address *ap, char *cap, int value, int whom)
{
    struct emul64   *emul64 = ADDR2EMUL64(ap);
    int     rval = 0;

    /*
     * We don't allow setting capabilities for other targets
     */
    if (cap == NULL || whom == 0) {
        return (-1);
    }

    EMUL64_MUTEX_ENTER(emul64);

    switch (scsi_hba_lookup_capstr(cap)) {
    case SCSI_CAP_DMA_MAX:
    case SCSI_CAP_MSG_OUT:
    case SCSI_CAP_PARITY:
    case SCSI_CAP_UNTAGGED_QING:
    case SCSI_CAP_LINKED_CMDS:
    case SCSI_CAP_RESET_NOTIFICATION:
        /*
         * None of these are settable via
         * the capability interface.
         */
        break;
    case SCSI_CAP_DISCONNECT:
        rval = 1;
        break;
    case SCSI_CAP_SYNCHRONOUS:
        rval = 1;
        break;
    case SCSI_CAP_TAGGED_QING:
        rval = 1;
        break;
    case SCSI_CAP_WIDE_XFER:
        rval = 1;
        break;
    case SCSI_CAP_INITIATOR_ID:
        rval = -1;
        break;
    case SCSI_CAP_ARQ:
        rval = 1;
        break;
    case SCSI_CAP_TOTAL_SECTORS:
        emul64->nt_total_sectors[ap->a_target][ap->a_lun] = value;
        rval = TRUE;
        break;
    case SCSI_CAP_SECTOR_SIZE:
        rval = TRUE;
        break;
    default:
        rval = -1;
        break;
    }


    EMUL64_MUTEX_EXIT(emul64);

    return (rval);
}

/*
 * Function name : emul64_scsi_init_pkt
 *
 * Return Values : pointer to scsi_pkt, or NULL
 * Description   : Called by kernel on behalf of a target driver
 *         calling scsi_init_pkt(9F).
 *         Refer to tran_init_pkt(9E) man page
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
/* ARGSUSED */
static struct scsi_pkt *
emul64_scsi_init_pkt(struct scsi_address *ap, struct scsi_pkt *pkt,
    struct buf *bp, int cmdlen, int statuslen, int tgtlen,
    int flags, int (*callback)(), caddr_t arg)
{
    struct emul64       *emul64 = ADDR2EMUL64(ap);
    struct emul64_cmd   *sp;

    ASSERT(callback == NULL_FUNC || callback == SLEEP_FUNC);

    /*
     * First step of emul64_scsi_init_pkt:  pkt allocation
     */
    if (pkt == NULL) {
        pkt = scsi_hba_pkt_alloc(emul64->emul64_dip, ap, cmdlen,
            statuslen,
            tgtlen, sizeof (struct emul64_cmd), callback, arg);
        if (pkt == NULL) {
            cmn_err(CE_WARN, "emul64_scsi_init_pkt: "
                "scsi_hba_pkt_alloc failed");
            return (NULL);
        }

        sp = PKT2CMD(pkt);

        /*
         * Initialize the new pkt - we redundantly initialize
         * all the fields for illustrative purposes.
         */
        sp->cmd_pkt     = pkt;
        sp->cmd_flags       = 0;
        sp->cmd_scblen      = statuslen;
        sp->cmd_cdblen      = cmdlen;
        sp->cmd_emul64      = emul64;
        pkt->pkt_address    = *ap;
        pkt->pkt_comp       = (void (*)())NULL;
        pkt->pkt_flags      = 0;
        pkt->pkt_time       = 0;
        pkt->pkt_resid      = 0;
        pkt->pkt_statistics = 0;
        pkt->pkt_reason     = 0;

    } else {
        sp = PKT2CMD(pkt);
    }

    /*
     * Second step of emul64_scsi_init_pkt:  dma allocation/move
     */
    if (bp && bp->b_bcount != 0) {
        if (bp->b_flags & B_READ) {
            sp->cmd_flags &= ~CFLAG_DMASEND;
        } else {
            sp->cmd_flags |= CFLAG_DMASEND;
        }
        bp_mapin(bp);
        sp->cmd_addr = (unsigned char *) bp->b_un.b_addr;
        sp->cmd_count = bp->b_bcount;
        pkt->pkt_resid = 0;
    }

    return (pkt);
}


/*
 * Function name : emul64_scsi_destroy_pkt
 *
 * Return Values : none
 * Description   : Called by kernel on behalf of a target driver
 *         calling scsi_destroy_pkt(9F).
 *         Refer to tran_destroy_pkt(9E) man page
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
static void
emul64_scsi_destroy_pkt(struct scsi_address *ap, struct scsi_pkt *pkt)
{
    struct emul64_cmd   *sp = PKT2CMD(pkt);

    /*
     * emul64_scsi_dmafree inline to make things faster
     */
    if (sp->cmd_flags & CFLAG_DMAVALID) {
        /*
         * Free the mapping.
         */
        sp->cmd_flags &= ~CFLAG_DMAVALID;
    }

    /*
     * Free the pkt
     */
    scsi_hba_pkt_free(ap, pkt);
}


/*
 * Function name : emul64_scsi_dmafree()
 *
 * Return Values : none
 * Description   : free dvma resources
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
/*ARGSUSED*/
static void
emul64_scsi_dmafree(struct scsi_address *ap, struct scsi_pkt *pkt)
{
}

/*
 * Function name : emul64_scsi_sync_pkt()
 *
 * Return Values : none
 * Description   : sync dma
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
/*ARGSUSED*/
static void
emul64_scsi_sync_pkt(struct scsi_address *ap, struct scsi_pkt *pkt)
{
}

/*
 * routine for reset notification setup, to register or cancel.
 */
static int
emul64_scsi_reset_notify(struct scsi_address *ap, int flag,
void (*callback)(caddr_t), caddr_t arg)
{
    struct emul64               *emul64 = ADDR2EMUL64(ap);
    struct emul64_reset_notify_entry    *p, *beforep;
    int                 rval = DDI_FAILURE;

    mutex_enter(EMUL64_REQ_MUTEX(emul64));

    p = emul64->emul64_reset_notify_listf;
    beforep = NULL;

    while (p) {
        if (p->ap == ap)
            break;  /* An entry exists for this target */
        beforep = p;
        p = p->next;
    }

    if ((flag & SCSI_RESET_CANCEL) && (p != NULL)) {
        if (beforep == NULL) {
            emul64->emul64_reset_notify_listf = p->next;
        } else {
            beforep->next = p->next;
        }
        kmem_free((caddr_t)p,
            sizeof (struct emul64_reset_notify_entry));
        rval = DDI_SUCCESS;

    } else if ((flag & SCSI_RESET_NOTIFY) && (p == NULL)) {
        p = kmem_zalloc(sizeof (struct emul64_reset_notify_entry),
            KM_SLEEP);
        p->ap = ap;
        p->callback = callback;
        p->arg = arg;
        p->next = emul64->emul64_reset_notify_listf;
        emul64->emul64_reset_notify_listf = p;
        rval = DDI_SUCCESS;
    }

    mutex_exit(EMUL64_REQ_MUTEX(emul64));

    return (rval);
}

/*
 * Function name : emul64_scsi_start()
 *
 * Return Values : TRAN_FATAL_ERROR - emul64 has been shutdown
 *         TRAN_BUSY        - request queue is full
 *         TRAN_ACCEPT      - pkt has been submitted to emul64
 *
 * Description   : init pkt, start the request
 *
 * Context   : Can be called from different kernel process threads.
 *         Can be called by interrupt thread.
 */
static int
emul64_scsi_start(struct scsi_address *ap, struct scsi_pkt *pkt)
{
    struct emul64_cmd   *sp = PKT2CMD(pkt);
    int         rval    = TRAN_ACCEPT;
    struct emul64       *emul64 = ADDR2EMUL64(ap);
    clock_t         cur_lbolt;
    taskqid_t       dispatched;

    ASSERT(mutex_owned(EMUL64_REQ_MUTEX(emul64)) == 0 || ddi_in_panic());
    ASSERT(mutex_owned(EMUL64_RESP_MUTEX(emul64)) == 0 || ddi_in_panic());

    EMUL64_DEBUG2(emul64, SCSI_DEBUG, "emul64_scsi_start %x", sp);

    pkt->pkt_reason = CMD_CMPLT;

#ifdef  EMUL64DEBUG
    if (emul64_cdb_debug) {
        emul64_debug_dump_cdb(ap, pkt);
    }
#endif  /* EMUL64DEBUG */

    /*
     * calculate deadline from pkt_time
     * Instead of multiplying by 100 (ie. HZ), we multiply by 128 so
     * we can shift and at the same time have a 28% grace period
     * we ignore the rare case of pkt_time == 0 and deal with it
     * in emul64_i_watch()
     */
    cur_lbolt = ddi_get_lbolt();
    sp->cmd_deadline = cur_lbolt + (pkt->pkt_time * 128);

    if ((emul64_usetaskq == 0) || (pkt->pkt_flags & FLAG_NOINTR) != 0) {
        emul64_pkt_comp((caddr_t)pkt);
    } else {
        dispatched = NULL;
        if (emul64_collect_stats) {
            /*
             * If we are collecting statistics, call
             * taskq_dispatch in no sleep mode, so that we can
             * detect if we are exceeding the queue length that
             * was established in the call to taskq_create in
             * emul64_attach.  If the no sleep call fails
             * (returns NULL), the task will be dispatched in
             * sleep mode below.
             */
            dispatched = taskq_dispatch(emul64->emul64_taskq,
                emul64_pkt_comp, (void *)pkt, TQ_NOSLEEP);
            if (dispatched == NULL) {
                /* Queue was full.  dispatch failed. */
                mutex_enter(&emul64_stats_mutex);
                emul64_taskq_max++;
                mutex_exit(&emul64_stats_mutex);
            }
        }
        if (dispatched == NULL) {
            (void) taskq_dispatch(emul64->emul64_taskq,
                emul64_pkt_comp, (void *)pkt, TQ_SLEEP);
        }
    }

done:
    ASSERT(mutex_owned(EMUL64_REQ_MUTEX(emul64)) == 0 || ddi_in_panic());
    ASSERT(mutex_owned(EMUL64_RESP_MUTEX(emul64)) == 0 || ddi_in_panic());

    return (rval);
}

void
emul64_check_cond(struct scsi_pkt *pkt, uchar_t key, uchar_t asc, uchar_t ascq)
{
    struct scsi_arq_status *arq =
        (struct scsi_arq_status *)pkt->pkt_scbp;

    /* got check, no data transferred and ARQ done */
    arq->sts_status.sts_chk = 1;
    pkt->pkt_state |= STATE_ARQ_DONE;
    pkt->pkt_state &= ~STATE_XFERRED_DATA;

    /* for ARQ */
    arq->sts_rqpkt_reason = CMD_CMPLT;
    arq->sts_rqpkt_resid = 0;
    arq->sts_rqpkt_state = STATE_GOT_BUS | STATE_GOT_TARGET |
        STATE_SENT_CMD | STATE_XFERRED_DATA | STATE_GOT_STATUS;
    arq->sts_sensedata.es_valid = 1;
    arq->sts_sensedata.es_class = 0x7;
    arq->sts_sensedata.es_key = key;
    arq->sts_sensedata.es_add_code = asc;
    arq->sts_sensedata.es_qual_code = ascq;
}

ushort_t
emul64_error_inject(struct scsi_pkt *pkt)
{
    struct emul64_cmd   *sp = PKT2CMD(pkt);
    emul64_tgt_t        *tgt;
    struct scsi_arq_status *arq =
        (struct scsi_arq_status *)pkt->pkt_scbp;
    uint_t          max_sense_len;

    EMUL64_MUTEX_ENTER(sp->cmd_emul64);
    tgt = find_tgt(sp->cmd_emul64,
        pkt->pkt_address.a_target, pkt->pkt_address.a_lun);
    EMUL64_MUTEX_EXIT(sp->cmd_emul64);

    /*
     * If there is no target, skip the error injection and
     * let the packet be handled normally.  This would normally
     * never happen since a_target and a_lun are setup in
     * emul64_scsi_init_pkt.
     */
    if (tgt == NULL) {
        return (ERR_INJ_DISABLE);
    }

    if (tgt->emul64_einj_state != ERR_INJ_DISABLE) {
        arq->sts_status = tgt->emul64_einj_scsi_status;
        pkt->pkt_state = tgt->emul64_einj_pkt_state;
        pkt->pkt_reason = tgt->emul64_einj_pkt_reason;

        /*
         * Calculate available sense buffer length.  We could just
         * assume sizeof(struct scsi_extended_sense) but hopefully
         * that limitation will go away soon.
         */
        max_sense_len = sp->cmd_scblen  -
            (sizeof (struct scsi_arq_status) -
            sizeof (struct scsi_extended_sense));
        if (max_sense_len > tgt->emul64_einj_sense_length) {
            max_sense_len = tgt->emul64_einj_sense_length;
        }

        /* for ARQ */
        arq->sts_rqpkt_reason = CMD_CMPLT;
        arq->sts_rqpkt_resid = 0;
        arq->sts_rqpkt_state = STATE_GOT_BUS | STATE_GOT_TARGET |
            STATE_SENT_CMD | STATE_XFERRED_DATA | STATE_GOT_STATUS;

        /* Copy sense data */
        if (tgt->emul64_einj_sense_data != 0) {
            bcopy(tgt->emul64_einj_sense_data,
                (uint8_t *)&arq->sts_sensedata,
                max_sense_len);
        }
    }

    /* Return current error injection state */
    return (tgt->emul64_einj_state);
}

int
emul64_error_inject_req(struct emul64 *emul64, intptr_t arg)
{
    emul64_tgt_t        *tgt;
    struct emul64_error_inj_data error_inj_req;

    /* Check args */
    if (arg == NULL) {
        return (EINVAL);
    }

    if (ddi_copyin((void *)arg, &error_inj_req,
        sizeof (error_inj_req), 0) != 0) {
        cmn_err(CE_WARN, "emul64: ioctl - inj copyin failed\n");
        return (EFAULT);
    }

    EMUL64_MUTEX_ENTER(emul64);
    tgt = find_tgt(emul64, error_inj_req.eccd_target,
        error_inj_req.eccd_lun);
    EMUL64_MUTEX_EXIT(emul64);

    /* Make sure device exists */
    if (tgt == NULL) {
        return (ENODEV);
    }

    /* Free old sense buffer if we have one */
    if (tgt->emul64_einj_sense_data != NULL) {
        ASSERT(tgt->emul64_einj_sense_length != 0);
        kmem_free(tgt->emul64_einj_sense_data,
            tgt->emul64_einj_sense_length);
        tgt->emul64_einj_sense_data = NULL;
        tgt->emul64_einj_sense_length = 0;
    }

    /*
     * Now handle error injection request.  If error injection
     * is requested we will return the sense data provided for
     * any I/O to this target until told to stop.
     */
    tgt->emul64_einj_state = error_inj_req.eccd_inj_state;
    tgt->emul64_einj_sense_length = error_inj_req.eccd_sns_dlen;
    tgt->emul64_einj_pkt_state = error_inj_req.eccd_pkt_state;
    tgt->emul64_einj_pkt_reason = error_inj_req.eccd_pkt_reason;
    tgt->emul64_einj_scsi_status = error_inj_req.eccd_scsi_status;
    switch (error_inj_req.eccd_inj_state) {
    case ERR_INJ_ENABLE:
    case ERR_INJ_ENABLE_NODATA:
        if (error_inj_req.eccd_sns_dlen) {
            tgt->emul64_einj_sense_data =
                kmem_alloc(error_inj_req.eccd_sns_dlen, KM_SLEEP);
            /* Copy sense data */
            if (ddi_copyin((void *)(arg + sizeof (error_inj_req)),
                tgt->emul64_einj_sense_data,
                error_inj_req.eccd_sns_dlen, 0) != 0) {
                cmn_err(CE_WARN,
                    "emul64: sense data copy in failed\n");
                return (EFAULT);
            }
        }
        break;
    case ERR_INJ_DISABLE:
    default:
        break;
    }

    return (0);
}

int bsd_scsi_start_stop_unit(struct scsi_pkt *);
int bsd_scsi_test_unit_ready(struct scsi_pkt *);
int bsd_scsi_request_sense(struct scsi_pkt *);
int bsd_scsi_inquiry(struct scsi_pkt *);
int bsd_scsi_format(struct scsi_pkt *);
int bsd_scsi_io(struct scsi_pkt *);
int bsd_scsi_log_sense(struct scsi_pkt *);
int bsd_scsi_mode_sense(struct scsi_pkt *);
int bsd_scsi_mode_select(struct scsi_pkt *);
int bsd_scsi_read_capacity(struct scsi_pkt *);
int bsd_scsi_read_capacity_16(struct scsi_pkt *);
int bsd_scsi_reserve(struct scsi_pkt *);
int bsd_scsi_format(struct scsi_pkt *);
int bsd_scsi_release(struct scsi_pkt *);
int bsd_scsi_read_defect_list(struct scsi_pkt *);
int bsd_scsi_reassign_block(struct scsi_pkt *);
int bsd_freeblkrange(emul64_tgt_t *, emul64_range_t *);

static void
emul64_handle_cmd(struct scsi_pkt *pkt)
{
    if (emul64_error_inject(pkt) == ERR_INJ_ENABLE_NODATA) {
        /*
         * If error injection is configured to return with
         * no data return now without handling the command.
         * This is how normal check conditions work.
         *
         * If the error injection state is ERR_INJ_ENABLE
         * (or if error injection is disabled) continue and
         * handle the command.  This would be used for
         * KEY_RECOVERABLE_ERROR type conditions.
         */
        return;
    }

    switch (pkt->pkt_cdbp[0]) {
    case SCMD_START_STOP:
        (void) bsd_scsi_start_stop_unit(pkt);
        break;
    case SCMD_TEST_UNIT_READY:
        (void) bsd_scsi_test_unit_ready(pkt);
        break;
    case SCMD_REQUEST_SENSE:
        (void) bsd_scsi_request_sense(pkt);
        break;
    case SCMD_INQUIRY:
        (void) bsd_scsi_inquiry(pkt);
        break;
    case SCMD_FORMAT:
        (void) bsd_scsi_format(pkt);
        break;
    case SCMD_READ:
    case SCMD_WRITE:
    case SCMD_READ_G1:
    case SCMD_WRITE_G1:
    case SCMD_READ_G4:
    case SCMD_WRITE_G4:
        (void) bsd_scsi_io(pkt);
        break;
    case SCMD_LOG_SENSE_G1:
        (void) bsd_scsi_log_sense(pkt);
        break;
    case SCMD_MODE_SENSE:
    case SCMD_MODE_SENSE_G1:
        (void) bsd_scsi_mode_sense(pkt);
        break;
    case SCMD_MODE_SELECT:
    case SCMD_MODE_SELECT_G1:
        (void) bsd_scsi_mode_select(pkt);
        break;
    case SCMD_READ_CAPACITY:
        (void) bsd_scsi_read_capacity(pkt);
        break;
    case SCMD_SVC_ACTION_IN_G4:
        if (pkt->pkt_cdbp[1] == SSVC_ACTION_READ_CAPACITY_G4) {
            (void) bsd_scsi_read_capacity_16(pkt);
        } else {
            cmn_err(CE_WARN, "emul64: unrecognized G4 service "
                "action 0x%x", pkt->pkt_cdbp[1]);
        }
        break;
    case SCMD_RESERVE:
    case SCMD_RESERVE_G1:
        (void) bsd_scsi_reserve(pkt);
        break;
    case SCMD_RELEASE:
    case SCMD_RELEASE_G1:
        (void) bsd_scsi_release(pkt);
        break;
    case SCMD_REASSIGN_BLOCK:
        (void) bsd_scsi_reassign_block(pkt);
        break;
    case SCMD_READ_DEFECT_LIST:
        (void) bsd_scsi_read_defect_list(pkt);
        break;
    case SCMD_PRIN:
    case SCMD_PROUT:
    case SCMD_REPORT_LUNS:
        /* ASC 0x24 INVALID FIELD IN CDB */
        emul64_check_cond(pkt, KEY_ILLEGAL_REQUEST, 0x24, 0x0);
        break;
    default:
        cmn_err(CE_WARN, "emul64: unrecognized "
            "SCSI cmd 0x%x", pkt->pkt_cdbp[0]);
        emul64_check_cond(pkt, KEY_ILLEGAL_REQUEST, 0x24, 0x0);
        break;
    case SCMD_GET_CONFIGURATION:
    case 0x35:          /* SCMD_SYNCHRONIZE_CACHE */
        /* Don't complain */
        break;
    }
}

static void
emul64_pkt_comp(void * arg)
{
    struct scsi_pkt     *pkt = (struct scsi_pkt *)arg;
    struct emul64_cmd   *sp = PKT2CMD(pkt);
    emul64_tgt_t        *tgt;

    EMUL64_MUTEX_ENTER(sp->cmd_emul64);
    tgt = find_tgt(sp->cmd_emul64,
        pkt->pkt_address.a_target, pkt->pkt_address.a_lun);
    EMUL64_MUTEX_EXIT(sp->cmd_emul64);
    if (!tgt) {
        pkt->pkt_reason = CMD_TIMEOUT;
        pkt->pkt_state = STATE_GOT_BUS | STATE_SENT_CMD;
        pkt->pkt_statistics = STAT_TIMEOUT;
    } else {
        pkt->pkt_reason = CMD_CMPLT;
        *pkt->pkt_scbp = STATUS_GOOD;
        pkt->pkt_state = STATE_GOT_BUS | STATE_GOT_TARGET |
            STATE_SENT_CMD | STATE_XFERRED_DATA | STATE_GOT_STATUS;
        pkt->pkt_statistics = 0;
        emul64_handle_cmd(pkt);
    }
    scsi_hba_pkt_comp(pkt);
}

/* ARGSUSED */
static int
emul64_scsi_abort(struct scsi_address *ap, struct scsi_pkt *pkt)
{
    return (1);
}

/* ARGSUSED */
static int
emul64_scsi_reset(struct scsi_address *ap, int level)
{
    return (1);
}

static int
emul64_get_tgtrange(struct emul64 *emul64,
            intptr_t arg,
            emul64_tgt_t **tgtp,
            emul64_tgt_range_t *tgtr)
{
    if (ddi_copyin((void *)arg, tgtr, sizeof (*tgtr), 0) != 0) {
        cmn_err(CE_WARN, "emul64: ioctl - copy in failed\n");
        return (EFAULT);
    }
    EMUL64_MUTEX_ENTER(emul64);
    *tgtp = find_tgt(emul64, tgtr->emul64_target, tgtr->emul64_lun);
    EMUL64_MUTEX_EXIT(emul64);
    if (*tgtp == NULL) {
        cmn_err(CE_WARN, "emul64: ioctl - no target for %d,%d on %d",
            tgtr->emul64_target, tgtr->emul64_lun,
            ddi_get_instance(emul64->emul64_dip));
        return (ENXIO);
    }
    return (0);
}

static int
emul64_ioctl(dev_t dev,
    int cmd,
    intptr_t arg,
    int mode,
    cred_t *credp,
    int *rvalp)
{
    struct emul64       *emul64;
    int         instance;
    int         rv = 0;
    emul64_tgt_range_t  tgtr;
    emul64_tgt_t        *tgt;

    instance = MINOR2INST(getminor(dev));
    emul64 = (struct emul64 *)ddi_get_soft_state(emul64_state, instance);
    if (emul64 == NULL) {
        cmn_err(CE_WARN, "emul64: ioctl - no softstate for %d\n",
            getminor(dev));
        return (ENXIO);
    }

    switch (cmd) {
    case EMUL64_WRITE_OFF:
        rv = emul64_get_tgtrange(emul64, arg, &tgt, &tgtr);
        if (rv == 0) {
            rv = emul64_write_off(emul64, tgt, &tgtr);
        }
        break;
    case EMUL64_WRITE_ON:
        rv = emul64_get_tgtrange(emul64, arg, &tgt, &tgtr);
        if (rv == 0) {
            rv = emul64_write_on(emul64, tgt, &tgtr);
        }
        break;
    case EMUL64_ZERO_RANGE:
        rv = emul64_get_tgtrange(emul64, arg, &tgt, &tgtr);
        if (rv == 0) {
            mutex_enter(&tgt->emul64_tgt_blk_lock);
            rv = bsd_freeblkrange(tgt, &tgtr.emul64_blkrange);
            mutex_exit(&tgt->emul64_tgt_blk_lock);
        }
        break;
    case EMUL64_ERROR_INJECT:
        rv = emul64_error_inject_req(emul64, arg);
        break;
    default:
        rv  = scsi_hba_ioctl(dev, cmd, arg, mode, credp, rvalp);
        break;
    }
    return (rv);
}

/* ARGSUSED */
static int
emul64_write_off(struct emul64 *emul64,
    emul64_tgt_t *tgt,
    emul64_tgt_range_t *tgtr)
{
    size_t          blkcnt = tgtr->emul64_blkrange.emul64_blkcnt;
    emul64_nowrite_t    *cur;
    emul64_nowrite_t    *nowrite;
    emul64_rng_overlap_t    overlap = O_NONE;
    emul64_nowrite_t    **prev = NULL;
    diskaddr_t      sb = tgtr->emul64_blkrange.emul64_sb;

    nowrite = emul64_nowrite_alloc(&tgtr->emul64_blkrange);

    /* Find spot in list */
    rw_enter(&tgt->emul64_tgt_nw_lock, RW_WRITER);
    cur = emul64_find_nowrite(tgt, sb, blkcnt, &overlap, &prev);
    if (overlap == O_NONE) {
        /* Insert into list */
        *prev = nowrite;
        nowrite->emul64_nwnext = cur;
    }
    rw_exit(&tgt->emul64_tgt_nw_lock);
    if (overlap == O_NONE) {
        if (emul64_collect_stats) {
            mutex_enter(&emul64_stats_mutex);
            emul64_nowrite_count++;
            mutex_exit(&emul64_stats_mutex);
        }
    } else {
        cmn_err(CE_WARN, "emul64: EMUL64_WRITE_OFF 0x%llx,0x%"
            PRIx64 "overlaps 0x%llx,0x%" PRIx64 "\n",
            nowrite->emul64_blocked.emul64_sb,
            nowrite->emul64_blocked.emul64_blkcnt,
            cur->emul64_blocked.emul64_sb,
            cur->emul64_blocked.emul64_blkcnt);
        emul64_nowrite_free(nowrite);
        return (EINVAL);
    }
    return (0);
}

/* ARGSUSED */
static int
emul64_write_on(struct emul64 *emul64,
        emul64_tgt_t *tgt,
        emul64_tgt_range_t *tgtr)
{
    size_t          blkcnt = tgtr->emul64_blkrange.emul64_blkcnt;
    emul64_nowrite_t    *cur;
    emul64_rng_overlap_t    overlap = O_NONE;
    emul64_nowrite_t    **prev = NULL;
    int         rv = 0;
    diskaddr_t      sb = tgtr->emul64_blkrange.emul64_sb;

    /* Find spot in list */
    rw_enter(&tgt->emul64_tgt_nw_lock, RW_WRITER);
    cur = emul64_find_nowrite(tgt, sb, blkcnt, &overlap, &prev);
    if (overlap == O_SAME) {
        /* Remove from list */
        *prev = cur->emul64_nwnext;
    }
    rw_exit(&tgt->emul64_tgt_nw_lock);

    switch (overlap) {
    case O_NONE:
        cmn_err(CE_WARN, "emul64: EMUL64_WRITE_ON 0x%llx,0x%lx "
            "range not found\n", sb, blkcnt);
        rv = ENXIO;
        break;
    case O_SAME:
        if (emul64_collect_stats) {
            mutex_enter(&emul64_stats_mutex);
            emul64_nowrite_count--;
            mutex_exit(&emul64_stats_mutex);
        }
        emul64_nowrite_free(cur);
        break;
    case O_OVERLAP:
    case O_SUBSET:
        cmn_err(CE_WARN, "emul64: EMUL64_WRITE_ON 0x%llx,0x%lx "
            "overlaps 0x%llx,0x%" PRIx64 "\n",
            sb, blkcnt, cur->emul64_blocked.emul64_sb,
            cur->emul64_blocked.emul64_blkcnt);
        rv = EINVAL;
        break;
    }
    return (rv);
}

static emul64_nowrite_t *
emul64_find_nowrite(emul64_tgt_t *tgt,
            diskaddr_t sb,
            size_t blkcnt,
            emul64_rng_overlap_t *overlap,
            emul64_nowrite_t ***prevp)
{
    emul64_nowrite_t    *cur;
    emul64_nowrite_t    **prev;

    /* Find spot in list */
    *overlap = O_NONE;
    prev = &tgt->emul64_tgt_nowrite;
    cur = tgt->emul64_tgt_nowrite;
    while (cur != NULL) {
        *overlap = emul64_overlap(&cur->emul64_blocked, sb, blkcnt);
        if (*overlap != O_NONE)
            break;
        prev = &cur->emul64_nwnext;
        cur = cur->emul64_nwnext;
    }

    *prevp = prev;
    return (cur);
}

static emul64_nowrite_t *
emul64_nowrite_alloc(emul64_range_t *range)
{
    emul64_nowrite_t    *nw;

    nw = kmem_zalloc(sizeof (*nw), KM_SLEEP);
    bcopy((void *) range,
        (void *) &nw->emul64_blocked,
        sizeof (nw->emul64_blocked));
    return (nw);
}

static void
emul64_nowrite_free(emul64_nowrite_t *nw)
{
    kmem_free((void *) nw, sizeof (*nw));
}

emul64_rng_overlap_t
emul64_overlap(emul64_range_t *rng, diskaddr_t sb, size_t cnt)
{

    if (rng->emul64_sb >= sb + cnt)
        return (O_NONE);
    if (rng->emul64_sb + rng->emul64_blkcnt <= sb)
        return (O_NONE);
    if ((rng->emul64_sb == sb) && (rng->emul64_blkcnt == cnt))
        return (O_SAME);
    if ((sb >= rng->emul64_sb) &&
        ((sb + cnt) <= (rng->emul64_sb + rng->emul64_blkcnt))) {
        return (O_SUBSET);
    }
    return (O_OVERLAP);
}

#include <sys/varargs.h>

/*
 * Error logging, printing, and debug print routines
 */

/*VARARGS3*/
static void
emul64_i_log(struct emul64 *emul64, int level, char *fmt, ...)
{
    char    buf[256];
    va_list ap;

    va_start(ap, fmt);
    (void) vsnprintf(buf, sizeof (buf), fmt, ap);
    va_end(ap);

    scsi_log(emul64 ? emul64->emul64_dip : NULL,
        "emul64", level, "%s\n", buf);
}


#ifdef EMUL64DEBUG

static void
emul64_debug_dump_cdb(struct scsi_address *ap, struct scsi_pkt *pkt)
{
    static char hex[]   = "0123456789abcdef";
    struct emul64   *emul64 = ADDR2EMUL64(ap);
    struct emul64_cmd   *sp = PKT2CMD(pkt);
    uint8_t     *cdb    = pkt->pkt_cdbp;
    char        buf [256];
    char        *p;
    int     i;

    (void) snprintf(buf, sizeof (buf), "emul64%d: <%d,%d> ",
        ddi_get_instance(emul64->emul64_dip),
        ap->a_target, ap->a_lun);

    p = buf + strlen(buf);

    *p++ = '[';
    for (i = 0; i < sp->cmd_cdblen; i++, cdb++) {
        if (i != 0)
            *p++ = ' ';
        *p++ = hex[(*cdb >> 4) & 0x0f];
        *p++ = hex[*cdb & 0x0f];
    }
    *p++ = ']';
    *p++ = '\n';
    *p = 0;

    cmn_err(CE_CONT, buf);
}
#endif  /* EMUL64DEBUG */