/*
 * 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, intptr_t, int, cred_t *, int *);

/*
 * 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 = TASKQID_INVALID;
                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 == TASKQID_INVALID) {
                                /* Queue was full.  dispatch failed. */
                                mutex_enter(&emul64_stats_mutex);
                                emul64_taskq_max++;
                                mutex_exit(&emul64_stats_mutex);
                        }
                }
                if (dispatched == TASKQID_INVALID) {
                        (void) taskq_dispatch(emul64->emul64_taskq,
                            emul64_pkt_comp, (void *)pkt, TQ_SLEEP);
                }
        }

        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 == (intptr_t)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 */