root/sys/dev/ic/wd33c93.c
/*      $NetBSD: wd33c93.c,v 1.38 2026/01/11 06:23:27 tsutsui Exp $     */

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Van Jacobson of Lawrence Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *  @(#)scsi.c  7.5 (Berkeley) 5/4/91
 */

/*
 * Changes Copyright (c) 2001 Wayne Knowles
 * Changes Copyright (c) 1996 Steve Woodford
 * Original Copyright (c) 1994 Christian E. Hopps
 *
 * This code is derived from software contributed to Berkeley by
 * Van Jacobson of Lawrence Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *  @(#)scsi.c  7.5 (Berkeley) 5/4/91
 */

/*
 * This version of the driver is pretty well generic, so should work with
 * any flavour of WD33C93 chip.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: wd33c93.c,v 1.38 2026/01/11 06:23:27 tsutsui Exp $");

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h> /* For hz */
#include <sys/disklabel.h>
#include <sys/buf.h>

#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsiconf.h>
#include <dev/scsipi/scsi_message.h>

#include <sys/bus.h>

#include <dev/ic/wd33c93reg.h>
#include <dev/ic/wd33c93var.h>

/*
 * SCSI delays
 * In u-seconds, primarily for state changes on the SPC.
 */
#define SBIC_CMD_WAIT   50000   /* wait per step of 'immediate' cmds */
#define SBIC_DATA_WAIT  50000   /* wait per data in/out step */
#define SBIC_INIT_WAIT  50000   /* wait per step (both) during init */

#define STATUS_UNKNOWN  0xff    /* uninitialized status */

/*
 * Convenience macro for waiting for a particular wd33c93 event
 */
#define SBIC_WAIT(regs, until, timeo) wd33c93_wait(regs, until, timeo, __LINE__)

void    wd33c93_init (struct wd33c93_softc *);
void    wd33c93_reset (struct wd33c93_softc *);
int     wd33c93_go (struct wd33c93_softc *, struct wd33c93_acb *);
int     wd33c93_dmaok (struct wd33c93_softc *, struct scsipi_xfer *);
int     wd33c93_wait (struct wd33c93_softc *, u_char, int , int);
u_char  wd33c93_selectbus (struct wd33c93_softc *, struct wd33c93_acb *);
int     wd33c93_xfout (struct wd33c93_softc *, int, void *);
int     wd33c93_xfin (struct wd33c93_softc *, int, void *);
int     wd33c93_poll (struct wd33c93_softc *, struct wd33c93_acb *);
int     wd33c93_nextstate (struct wd33c93_softc *, struct wd33c93_acb *,
                                u_char, u_char);
int     wd33c93_abort (struct wd33c93_softc *, struct wd33c93_acb *,
     const char *);
void    wd33c93_xferdone (struct wd33c93_softc *);
void    wd33c93_error (struct wd33c93_softc *, struct wd33c93_acb *,
                        const char *);
void    wd33c93_scsidone (struct wd33c93_softc *, struct wd33c93_acb *, int);
void    wd33c93_sched (struct wd33c93_softc *);
void    wd33c93_dequeue (struct wd33c93_softc *, struct wd33c93_acb *);
void    wd33c93_dma_stop (struct wd33c93_softc *);
void    wd33c93_dma_setup (struct wd33c93_softc *, int);
int     wd33c93_msgin_phase (struct wd33c93_softc *, int);
void    wd33c93_msgin (struct wd33c93_softc *, u_char *, int);
void    wd33c93_reselect (struct wd33c93_softc *, int, int, int, int);
void    wd33c93_sched_msgout (struct wd33c93_softc *, u_short);
void    wd33c93_msgout (struct wd33c93_softc *);
void    wd33c93_timeout_callout (void *arg);
int     wd33c93_timeout (struct wd33c93_acb *);
void    wd33c93_watchdog (void *arg);
u_char  wd33c93_stp2syn (struct wd33c93_softc *, struct wd33c93_tinfo *);
void    wd33c93_setsync (struct wd33c93_softc *, struct wd33c93_tinfo *);
void    wd33c93_update_xfer_mode (struct wd33c93_softc *, int);

static struct pool wd33c93_pool;                /* Adapter Control Blocks */
static int wd33c93_pool_initialized = 0;

/*
 * Timeouts
 */
int     wd33c93_cmd_wait        = SBIC_CMD_WAIT;
int     wd33c93_data_wait       = SBIC_DATA_WAIT;
int     wd33c93_init_wait       = SBIC_INIT_WAIT;

int     wd33c93_nodma           = 0;    /* Use polled IO transfers */
int     wd33c93_nodisc          = 0;    /* Allow command queues */
int     wd33c93_notags          = 0;    /* No Tags */

/*
 * Some useful stuff for debugging purposes
 */
#ifdef DEBUG

#define QPRINTF(a)      SBIC_DEBUG(MISC, a)

int     wd33c93_debug   = 0;            /* Debug flags */

void    wd33c93_print_csr (u_char);
void    wd33c93_hexdump (u_char *, int);

#else
#define QPRINTF(a)  /* */
#endif

static const char *wd33c93_chip_names[] = SBIC_CHIP_LIST;

/*
 * Attach instance of driver and probe for sub devices
 */
void
wd33c93_attach(struct wd33c93_softc *sc)
{
        struct scsipi_adapter *adapt = &sc->sc_adapter;
        struct scsipi_channel *chan = &sc->sc_channel;

        adapt->adapt_dev = sc->sc_dev;
        adapt->adapt_nchannels = 1;
        adapt->adapt_openings = 256;
        adapt->adapt_max_periph = 256; /* Max tags per device */
        adapt->adapt_ioctl = NULL;
        /* adapt_request initialized by MD interface */
        /* adapt_minphys initialized by MD interface */

        memset(chan, 0, sizeof(*chan));
        chan->chan_adapter = &sc->sc_adapter;
        chan->chan_bustype = &scsi_bustype;
        chan->chan_channel = 0;
        chan->chan_ntargets = SBIC_NTARG;
        chan->chan_nluns = SBIC_NLUN;
        chan->chan_id = sc->sc_id;

        callout_init(&sc->sc_watchdog, 0);

        /*
         * Add reference to adapter so that we drop the reference after
         * config_found() to make sure the adapter is disabled.
         */
        if (scsipi_adapter_addref(&sc->sc_adapter) != 0) {
                aprint_error_dev(sc->sc_dev, "unable to enable controller\n");
                return;
        }

        sc->sc_cfflags = device_cfdata(sc->sc_dev)->cf_flags;
        wd33c93_init(sc);
        
        aprint_normal(": %s (%d.%d MHz clock, %s, SCSI ID %d)\n",
            wd33c93_chip_names[sc->sc_chip],
            sc->sc_clkfreq / 10, sc->sc_clkfreq % 10,
            (sc->sc_dmamode == SBIC_CTL_DMA) ? "DMA" :
            (sc->sc_dmamode == SBIC_CTL_DBA_DMA) ? "DBA" :
            (sc->sc_dmamode == SBIC_CTL_BURST_DMA) ? "BURST DMA" : "PIO",
            sc->sc_channel.chan_id);
        if (sc->sc_chip == SBIC_CHIP_WD33C93B) {
                aprint_normal_dev(sc->sc_dev, "microcode revision 0x%02x",
                    sc->sc_rev);
                if (sc->sc_minsyncperiod < 50)
                        aprint_normal(", Fast SCSI");
                aprint_normal("\n");
        }

        sc->sc_child = config_found(sc->sc_dev, &sc->sc_channel,
                                     scsiprint, CFARGS_NONE);
        scsipi_adapter_delref(&sc->sc_adapter);
}

/*
 * Initialize driver-private structures
 */
void
wd33c93_init(struct wd33c93_softc *sc)
{
        u_int i;

        if (!wd33c93_pool_initialized) {
                /* All instances share the same pool */
                pool_init(&wd33c93_pool, sizeof(struct wd33c93_acb), 0, 0, 0,
                    "wd33c93_acb", NULL, IPL_BIO);
                ++wd33c93_pool_initialized;
        }

        if (sc->sc_state == 0) {
                TAILQ_INIT(&sc->ready_list);

                sc->sc_nexus = NULL;
                sc->sc_disc  = 0;
                memset(sc->sc_tinfo, 0, sizeof(sc->sc_tinfo));

                callout_reset(&sc->sc_watchdog, 60 * hz, wd33c93_watchdog, sc);
        } else
                panic("wd33c93: reinitializing driver!");

        sc->sc_flags = 0;
        sc->sc_state = SBIC_IDLE;
        wd33c93_reset(sc);

        for (i = 0; i < 8; i++) {
                struct wd33c93_tinfo *ti = &sc->sc_tinfo[i];
                /*
                 * cf_flags = 0xTTSSRR
                 *
                 *   TT = Bitmask to disable Tagged Queues
                 *   SS = Bitmask to disable Sync negotiation
                 *   RR = Bitmask to disable disconnect/reselect
                 */
                ti->flags = T_NEED_RESET;
                if (CFFLAGS_NOSYNC(sc->sc_cfflags, i))
                        ti->flags |= T_NOSYNC;
                if (CFFLAGS_NODISC(sc->sc_cfflags, i) || wd33c93_nodisc)
                        ti->flags |= T_NODISC;
                ti->period = sc->sc_minsyncperiod;
                ti->offset = 0;
        }
}

void
wd33c93_reset(struct wd33c93_softc *sc)
{
        u_int   my_id, s, div, i;
        u_char  csr, reg;

        SET_SBIC_cmd(sc, SBIC_CMD_ABORT);
        WAIT_CIP(sc);

        s = splbio();

        if (sc->sc_reset != NULL)
                (*sc->sc_reset)(sc);

        my_id = sc->sc_channel.chan_id & SBIC_ID_MASK;

        /* Enable advanced features and really(!) advanced features */
#if 1
        my_id |= (SBIC_ID_EAF | SBIC_ID_RAF);   /* XXX - MD Layer */
#endif

        SET_SBIC_myid(sc, my_id);

        /* Reset the chip */
        SET_SBIC_cmd(sc, SBIC_CMD_RESET);
        DELAY(25);
        SBIC_WAIT(sc, SBIC_ASR_INT, 0);

        /* Set up various chip parameters */
        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);

        GET_SBIC_csr(sc, csr);                  /* clears interrupt also */
        GET_SBIC_cdb1(sc, sc->sc_rev);          /* valid with RAF on wd33c93b */

        switch (csr) {
        case SBIC_CSR_RESET:
                sc->sc_chip = SBIC_CHIP_WD33C93;
                break;
        case SBIC_CSR_RESET_AM:
                SET_SBIC_queue_tag(sc, 0x55);
                GET_SBIC_queue_tag(sc, reg);
                sc->sc_chip = (reg == 0x55) ?
                               SBIC_CHIP_WD33C93B : SBIC_CHIP_WD33C93A;
                SET_SBIC_queue_tag(sc, 0x0);
                break;
        default:
                sc->sc_chip = SBIC_CHIP_UNKNOWN;
        }

        /*
         * Choose a suitable clock divisor and work out the resulting
         * sync transfer periods in 4ns units.
         */
        if (sc->sc_clkfreq < 110) {
                my_id |= SBIC_ID_FS_8_10;
                div = 2;
        } else if (sc->sc_clkfreq < 160) {
                my_id |= SBIC_ID_FS_12_15;
                div = 3;
        } else if (sc->sc_clkfreq < 210) {
                my_id |= SBIC_ID_FS_16_20;
                div = 4;
        } else
                panic("wd33c93: invalid clock speed %d", sc->sc_clkfreq);

        for (i = 0; i < 7; i++)
                sc->sc_syncperiods[i] =
                    (i + 2) * div * 1250 / sc->sc_clkfreq;
        sc->sc_minsyncperiod = sc->sc_syncperiods[0];
        SBIC_DEBUG(SYNC, ("available sync periods: %d %d %d %d %d %d %d\n",
            sc->sc_syncperiods[0], sc->sc_syncperiods[1],
            sc->sc_syncperiods[2], sc->sc_syncperiods[3],
            sc->sc_syncperiods[4], sc->sc_syncperiods[5],
            sc->sc_syncperiods[6]));

        if (sc->sc_clkfreq >= 160 && sc->sc_chip == SBIC_CHIP_WD33C93B) {
                for (i = 0; i < 3; i++)
                        sc->sc_fsyncperiods[i] =
                            (i + 2) * 2 * 1250 / sc->sc_clkfreq;
                SBIC_DEBUG(SYNC, ("available fast sync periods: %d %d %d\n",
                    sc->sc_fsyncperiods[0], sc->sc_fsyncperiods[1],
                    sc->sc_fsyncperiods[2]));
                sc->sc_minsyncperiod = sc->sc_fsyncperiods[0];
        }

        /* Max Sync Offset */
        if (sc->sc_chip == SBIC_CHIP_WD33C93A ||
            sc->sc_chip == SBIC_CHIP_WD33C93B)
                sc->sc_maxoffset = SBIC_SYN_93AB_MAX_OFFSET;
        else
                sc->sc_maxoffset = SBIC_SYN_93_MAX_OFFSET;

        /*
         * don't allow Selection (SBIC_RID_ES)
         * until we can handle target mode!!
         */
        SET_SBIC_rselid(sc, SBIC_RID_ER);

        /* Asynchronous for now */
        SET_SBIC_syn(sc, 0);

        sc->sc_flags = 0;
        sc->sc_state = SBIC_IDLE;

        splx(s);
}

void
wd33c93_error(struct wd33c93_softc *sc, struct wd33c93_acb *acb,
    const char *str)
{
        struct scsipi_xfer *xs = acb->xs;

        KASSERT(xs);

        if (xs->xs_control & XS_CTL_SILENT)
                return;

        scsipi_printaddr(xs->xs_periph);
        printf("SCSI Error (%s)\n", str);
}

/*
 * Determine an appropriate value for the synchronous transfer register
 * given the period and offset values in *ti.
 */
u_char
wd33c93_stp2syn(struct wd33c93_softc *sc, struct wd33c93_tinfo *ti)
{
        unsigned i;

        /* see if we can handle fast scsi (100-200ns) first */
        if (ti->period < 50 && sc->sc_minsyncperiod < 50) {
                for (i = 0; i < 3; i++)
                        if (sc->sc_fsyncperiods[i] >= ti->period)
                                return (SBIC_SYN(ti->offset, i + 2, 1));
        }

        for (i = 0; i < 7; i++) {
                if (sc->sc_syncperiods[i] >= ti->period) {
                        if (i == 6)
                                return (SBIC_SYN(0, 0, 0));
                        else
                                return (SBIC_SYN(ti->offset, i + 2, 0));
                }
        }

        /* XXX - can't handle it; do async */
        return (SBIC_SYN(0, 0, 0));
}

/*
 * Setup sync mode for given target
 */
void
wd33c93_setsync(struct wd33c93_softc *sc, struct wd33c93_tinfo *ti)
{
        u_char syncreg;

        if (ti->flags & T_SYNCMODE)
                syncreg = wd33c93_stp2syn(sc, ti);
        else
                syncreg = SBIC_SYN(0, 0, 0);

        SBIC_DEBUG(SYNC, ("wd33c93_setsync: sync reg = 0x%02x\n", syncreg));
        SET_SBIC_syn(sc, syncreg);
}

/*
 * Check if current operation can be done using DMA
 *
 * returns 1 if DMA OK, 0 for polled I/O transfer
 */
int
wd33c93_dmaok(struct wd33c93_softc *sc, struct scsipi_xfer *xs)
{
        if (wd33c93_nodma || sc->sc_dmamode == SBIC_CTL_NO_DMA ||
            (xs->xs_control & XS_CTL_POLL) || xs->datalen == 0)
                return (0);
        return(1);
}

/*
 * Setup for DMA transfer
 */
void
wd33c93_dma_setup(struct wd33c93_softc *sc, int datain)
{
        struct wd33c93_acb *acb = sc->sc_nexus;
        int s;

        sc->sc_daddr = acb->daddr;
        sc->sc_dleft = acb->dleft;

        s = splbio();
        /* Indicate that we're in DMA mode */
        if (sc->sc_dleft) {
                sc->sc_dmasetup(sc, &sc->sc_daddr, &sc->sc_dleft,
                    datain, &sc->sc_dleft);
        }
        splx(s);
        return;
}


/*
 * Save DMA pointers.  Take into account partial transfer. Shut down DMA.
 */
void
wd33c93_dma_stop(struct wd33c93_softc *sc)
{
        size_t count;
        int asr;

        /* Wait until WD chip is idle */
        do {
                GET_SBIC_asr(sc, asr);  /* XXX */
                if (asr & SBIC_ASR_DBR) {
                        printf("wd33c93_dma_stop: asr %02x canceled!\n", asr);
                        break;
                }
        } while (asr & (SBIC_ASR_BSY|SBIC_ASR_CIP));

        /* Only need to save pointers if DMA was active */
        if (sc->sc_flags & SBICF_INDMA) {
                int s = splbio();

                /* Shut down DMA and flush FIFO's */
                sc->sc_dmastop(sc);

                /* Fetch the residual count */
                SBIC_TC_GET(sc, count);

                /* Work out how many bytes were actually transferred */
                count = sc->sc_tcnt - count;

                if (sc->sc_dleft < count)
                        printf("xfer too large: dleft=%zu resid=%zu\n",
                            sc->sc_dleft, count);

                /* Fixup partial xfers */
                sc->sc_daddr = (char *)sc->sc_daddr + count;
                sc->sc_dleft -= count;
                sc->sc_tcnt   = 0;
                sc->sc_flags &= ~SBICF_INDMA;
                splx(s);
                SBIC_DEBUG(DMA, ("dma_stop\n"));
        }
        /*
         * Ensure the WD chip is back in polled I/O mode, with nothing to
         * transfer.
         */
        SBIC_TC_PUT(sc, 0);
        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);
}


/*
 * Handle new request from scsipi layer
 */
void
wd33c93_scsi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req, void *arg)
{
        struct wd33c93_softc *sc =
            device_private(chan->chan_adapter->adapt_dev);
        struct scsipi_xfer *xs;
        struct scsipi_periph *periph;
        struct wd33c93_acb *acb;
        int flags, s;

        SBIC_DEBUG(SCSIREQ, ("%s: req 0x%x\n", __func__, (int)req));

        switch (req) {
        case ADAPTER_REQ_RUN_XFER:
                xs = arg;
                periph = xs->xs_periph;
                flags = xs->xs_control;

                if (flags & XS_CTL_DATA_UIO)
                        panic("wd33c93: scsi data uio requested");

                if (sc->sc_nexus && (flags & XS_CTL_POLL))
                        panic("wd33c93_scsicmd: busy");

                s = splbio();
                acb = pool_get(&wd33c93_pool, PR_NOWAIT);
                splx(s);

                if (acb == NULL) {
                        scsipi_printaddr(periph);
                        printf("cannot allocate acb\n");
                        xs->error = XS_RESOURCE_SHORTAGE;
                        scsipi_done(xs);
                        return;
                }

                SBIC_DEBUG(SCSIREQ,
                    ("wd33c93_scsi_request: RUN_XFER: acb %p\n", acb));

                acb->flags = ACB_ACTIVE;
                acb->xs    = xs;
                acb->clen  = xs->cmdlen;
                acb->daddr = xs->data;
                acb->dleft = xs->datalen;
                acb->timeout = xs->timeout;
                memcpy(&acb->cmd, xs->cmd, xs->cmdlen);

                if (flags & XS_CTL_POLL) {
                        /*
                         * Complete currently active command(s) before
                         * issuing an immediate command
                         */
                        while (sc->sc_nexus)
                                wd33c93_poll(sc, sc->sc_nexus);
                }

                s = splbio();
                TAILQ_INSERT_TAIL(&sc->ready_list, acb, chain);
                acb->flags |= ACB_READY;

                /* If nothing is active, try to start it now. */
                if (sc->sc_state == SBIC_IDLE)
                        wd33c93_sched(sc);
                splx(s);

                if ((flags & XS_CTL_POLL) == 0)
                        return;

                if (wd33c93_poll(sc, acb)) {
                        wd33c93_timeout(acb);
                        if (wd33c93_poll(sc, acb)) /* 2nd retry for ABORT */
                                wd33c93_timeout(acb);
                }
                return;

        case ADAPTER_REQ_GROW_RESOURCES:
                SBIC_DEBUG(SCSIREQ, ("%s: GROW_RESOURCES, UNSUPPORTED\n",
                    __func__));
                /* XXX Not supported. */
                /* XXX TODO: should fail the request */
                return;

        case ADAPTER_REQ_SET_XFER_MODE:
            {
                struct wd33c93_tinfo *ti;
                struct scsipi_xfer_mode *xm = arg;

                ti = &sc->sc_tinfo[xm->xm_target];
                ti->flags &= ~T_WANTSYNC;

                SBIC_DEBUG(SCSIREQ, ("%s: REQ_SET_XFER_MODE\n", __func__));

                if ((CFFLAGS_NOTAGS(sc->sc_cfflags, xm->xm_target) == 0) &&
                    (xm->xm_mode & PERIPH_CAP_TQING) && !wd33c93_notags)
                        ti->flags |= T_TAG;
                else
                        ti->flags &= ~T_TAG;

                SBIC_DEBUG(SYNC, ("wd33c93_scsi_request: "
                    "target %d: scsipi requested %s\n", xm->xm_target,
                    (xm->xm_mode & PERIPH_CAP_SYNC) ? "sync" : "async"));

                if ((xm->xm_mode & PERIPH_CAP_SYNC) != 0 &&
                    (ti->flags & T_NOSYNC) == 0)
                        ti->flags |= T_WANTSYNC;
                /*
                 * If we're not going to negotiate, send the notification
                 * now, since it won't happen later.
                 */
                if (!(ti->flags & T_WANTSYNC) == !(ti->flags & T_SYNCMODE))
                        wd33c93_update_xfer_mode(sc, xm->xm_target);
                else
                        ti->flags |= T_NEGOTIATE;
                return;
            }

        }
}

/*
 * attempt to start the next available command
 */
void
wd33c93_sched(struct wd33c93_softc *sc)
{
        struct scsipi_periph *periph = NULL; /* Gag the compiler */
        struct wd33c93_acb *acb;
        struct wd33c93_tinfo *ti;
        struct wd33c93_linfo *li;
        int lun, tag, flags;

        if (sc->sc_state != SBIC_IDLE)
                return;

        KASSERT(sc->sc_nexus == NULL);

        /* Loop through the ready list looking for work to do... */
        TAILQ_FOREACH(acb, &sc->ready_list, chain) {
                periph = acb->xs->xs_periph;
                lun = periph->periph_lun;
                ti = &sc->sc_tinfo[periph->periph_target];
                li = TINFO_LUN(ti, lun);

                KASSERT(acb->flags & ACB_READY);

                /* Select type of tag for this command */
                if ((ti->flags & T_NODISC) != 0)
                        tag = 0;
                else if ((ti->flags & T_TAG) == 0)
                        tag = 0;
                else if ((acb->flags & ACB_SENSE) != 0)
                        tag = 0;
                else if (acb->xs->xs_control & XS_CTL_POLL)
                        tag = 0; /* No tags for polled commands */
                else
                        tag = acb->xs->xs_tag_type;

                if (li == NULL) {
                        /* Initialize LUN info and add to list. */
                        li = malloc(sizeof(*li), M_DEVBUF, M_NOWAIT);
                        if (li == NULL)
                                continue;
                        memset(li, 0, sizeof(*li));
                        li->lun = lun;
                        if (lun < SBIC_NLUN)
                                ti->lun[lun] = li;
                }
                li->last_used = time_second;

                /*
                 * We've found a potential command, but is the target/lun busy?
                 */

                if (tag == 0 && li->untagged == NULL)
                        li->untagged = acb; /* Issue untagged */

                if (li->untagged != NULL) {
                        tag = 0;
                        if ((li->state != L_STATE_BUSY) && li->used == 0) {
                                /* Issue this untagged command now */
                                acb = li->untagged;
                                periph = acb->xs->xs_periph;
                        } else  /* Not ready yet */
                                continue;
                }

                acb->tag_type = tag;
                if (tag != 0) {
                        if (li->queued[acb->xs->xs_tag_id])
                                printf("queueing to active tag\n");
                        li->queued[acb->xs->xs_tag_id] = acb;
                        acb->tag_id = acb->xs->xs_tag_id;
                        li->used++;
                        break;
                }
                if (li->untagged != NULL && (li->state != L_STATE_BUSY)) {
                        li->state = L_STATE_BUSY;
                        break;
                }
                if (li->untagged == NULL && tag != 0) {
                        break;
                } else
                        printf("%d:%d busy\n", periph->periph_target,
                            periph->periph_lun);
        }

        if (acb == NULL) {
                SBIC_DEBUG(ACBS, ("wd33c93sched: no work\n"));
                return;                 /* did not find an available command */
        }

        SBIC_DEBUG(ACBS, ("wd33c93_sched(%d,%d)\n", periph->periph_target,
                       periph->periph_lun));

        TAILQ_REMOVE(&sc->ready_list, acb, chain);
        acb->flags &= ~ACB_READY;

        flags = acb->xs->xs_control;
        if (flags & XS_CTL_RESET)
                wd33c93_reset(sc);

        /* XXX - Implicitly call scsidone on select timeout */
        if (wd33c93_go(sc, acb) != 0 || acb->xs->error == XS_SELTIMEOUT) {
                acb->dleft = sc->sc_dleft;
                wd33c93_scsidone(sc, acb, sc->sc_status);
                return;
        }

        return;
}

void
wd33c93_scsidone(struct wd33c93_softc *sc, struct wd33c93_acb *acb, int status)
{
        struct scsipi_xfer      *xs = acb->xs;
        struct wd33c93_tinfo    *ti;
        struct wd33c93_linfo    *li;
        int                     s;

#ifdef DIAGNOSTIC
        KASSERT(sc->target == xs->xs_periph->periph_target);
        KASSERT(sc->lun    == xs->xs_periph->periph_lun);
        if (acb == NULL || xs == NULL) {
                panic("wd33c93_scsidone -- (%d,%d) no scsipi_xfer",
                    sc->target, sc->lun);
        }
        KASSERT(acb->flags != ACB_FREE);
#endif

        SBIC_DEBUG(ACBS, ("scsidone: (%d,%d)->(%d,%d)%02x\n",
                       xs->xs_periph->periph_target, xs->xs_periph->periph_lun,
                       sc->target, sc->lun, status));
        callout_stop(&xs->xs_callout);

        xs->status = status & SCSI_STATUS_MASK;
        xs->resid = acb->dleft;

        if (xs->error == XS_NOERROR) {
                switch (xs->status) {
                case SCSI_CHECK:
                case SCSI_TERMINATED:
                        /* XXX Need to read sense - return busy for now */
                        /*FALLTHROUGH*/
                case SCSI_QUEUE_FULL:
                case SCSI_BUSY:
                        xs->error = XS_BUSY;
                        break;
                }
        }

        ti = &sc->sc_tinfo[sc->target];
        li = TINFO_LUN(ti, sc->lun);
        ti->cmds++;
        if (xs->error == XS_SELTIMEOUT) {
                /* Selection timeout -- discard this LUN if empty */
                if (li->untagged == NULL && li->used == 0) {
                        if (sc->lun < SBIC_NLUN)
                                ti->lun[sc->lun] = NULL;
                        free(li, M_DEVBUF);
                }
        }

        wd33c93_dequeue(sc, acb);
        if (sc->sc_nexus == acb) {
                sc->sc_state = SBIC_IDLE;
                sc->sc_nexus = NULL;
                sc->sc_flags = 0;

                if (!TAILQ_EMPTY(&sc->ready_list))
                        wd33c93_sched(sc);
        }

        /* place control block back on free list. */
        s = splbio();
        acb->flags = ACB_FREE;
        pool_put(&wd33c93_pool, acb);
        splx(s);

        scsipi_done(xs);
}

void
wd33c93_dequeue(struct wd33c93_softc *sc, struct wd33c93_acb *acb)
{
        struct wd33c93_tinfo *ti = &sc->sc_tinfo[acb->xs->xs_periph->periph_target];
        struct wd33c93_linfo *li;
        int lun = acb->xs->xs_periph->periph_lun;

        li = TINFO_LUN(ti, lun);
#ifdef DIAGNOSTIC
        if (li == NULL || li->lun != lun)
                panic("wd33c93_dequeue: lun %d for ecb %p does not exist",
                      lun, acb);
#endif
        if (li->untagged == acb) {
                li->state = L_STATE_IDLE;
                li->untagged = NULL;
        }
        if (acb->tag_type && li->queued[acb->tag_id] != NULL) {
#ifdef DIAGNOSTIC
                if (li->queued[acb->tag_id] != NULL &&
                    (li->queued[acb->tag_id] != acb))
                        panic("wd33c93_dequeue: slot %d for lun %d has %p "
                            "instead of acb %p\n", acb->tag_id,
                            lun, li->queued[acb->tag_id], acb);
#endif
                li->queued[acb->tag_id] = NULL;
                li->used--;
        }
}


int
wd33c93_wait(struct wd33c93_softc *sc, u_char until, int timeo, int line)
{
        u_char val;

        if (timeo == 0)
                timeo = 1000000;        /* some large value.. */
        GET_SBIC_asr(sc, val);
        while ((val & until) == 0) {
                if (timeo-- == 0) {
                        int csr;
                        GET_SBIC_csr(sc, csr);
                        printf("wd33c93_wait: TIMEO @%d with asr=x%x csr=x%x\n",
                            line, val, csr);
#if defined(DDB) && defined(DEBUG)
                        Debugger();
#endif
                        return(val); /* Maybe I should abort */
                        break;
                }
                DELAY(1);
                GET_SBIC_asr(sc, val);
        }
        return(val);
}

int
wd33c93_abort(struct wd33c93_softc *sc, struct wd33c93_acb *acb,
     const char *where)
{
        u_char csr, asr;

        GET_SBIC_asr(sc, asr);
        GET_SBIC_csr(sc, csr);

        scsipi_printaddr(acb->xs->xs_periph);
        printf ("ABORT in %s: csr=0x%02x, asr=0x%02x\n", where, csr, asr);

        acb->timeout = SBIC_ABORT_TIMEOUT;
        acb->flags |= ACB_ABORT;

        /*
         * Clean up chip itself
         */
        if (sc->sc_nexus == acb) {
                /* Reschedule timeout. */
                callout_reset(&acb->xs->xs_callout, mstohz(acb->timeout),
                    wd33c93_timeout_callout, acb);

                while (asr & SBIC_ASR_DBR) {
                        /*
                         * wd33c93 is jammed w/data. need to clear it
                         * But we don't know what direction it needs to go
                         */
                        GET_SBIC_data(sc, asr);
                        printf("abort %s: clearing data buffer 0x%02x\n",
                               where, asr);
                        GET_SBIC_asr(sc, asr);
                        if (asr & SBIC_ASR_DBR) /* Not the read direction */
                                SET_SBIC_data(sc, asr);
                        GET_SBIC_asr(sc, asr);
                }

                scsipi_printaddr(acb->xs->xs_periph);
                printf("sending ABORT command\n");

                WAIT_CIP(sc);
                SET_SBIC_cmd(sc, SBIC_CMD_ABORT);
                WAIT_CIP(sc);

                GET_SBIC_asr(sc, asr);

                scsipi_printaddr(acb->xs->xs_periph);
                if (asr & (SBIC_ASR_BSY|SBIC_ASR_LCI)) {
                        /*
                         * ok, get more drastic..
                         */
                        printf("Resetting bus\n");
                        wd33c93_reset(sc);
                } else {
                        printf("sending DISCONNECT to target\n");
                        SET_SBIC_cmd(sc, SBIC_CMD_DISC);
                        WAIT_CIP(sc);

                        do {
                                SBIC_WAIT (sc, SBIC_ASR_INT, 0);
                                GET_SBIC_asr(sc, asr);
                                GET_SBIC_csr(sc, csr);
                                SBIC_DEBUG(MISC, ("csr: 0x%02x, asr: 0x%02x\n",
                                               csr, asr));
                        } while ((csr != SBIC_CSR_DISC) &&
                            (csr != SBIC_CSR_DISC_1) &&
                            (csr != SBIC_CSR_CMD_INVALID));
                }
                sc->sc_state = SBIC_ERROR;
                sc->sc_flags = 0;
        }
        return SBIC_STATE_ERROR;
}


/*
 * select the bus, return when selected or error.
 *
 * Returns the current CSR following selection and optionally MSG out phase.
 * i.e. the returned CSR *should* indicate CMD phase...
 * If the return value is 0, some error happened.
 */
u_char
wd33c93_selectbus(struct wd33c93_softc *sc, struct wd33c93_acb *acb)
{
        struct scsipi_xfer *xs = acb->xs;
        struct wd33c93_tinfo *ti;
        u_char target, lun, asr, csr, id;

        KASSERT(sc->sc_state == SBIC_IDLE);

        target = xs->xs_periph->periph_target;
        lun    = xs->xs_periph->periph_lun;
        ti     = &sc->sc_tinfo[target];

        sc->sc_state = SBIC_SELECTING;
        sc->target    = target;
        sc->lun       = lun;

        SBIC_DEBUG(PHASE, ("wd33c93_selectbus %d: ", target));

        if ((xs->xs_control & XS_CTL_POLL) == 0)
                callout_reset(&xs->xs_callout, mstohz(acb->timeout),
                    wd33c93_timeout_callout, acb);

        /*
         * issue select
         */
        SBIC_TC_PUT(sc, 0);
        SET_SBIC_selid(sc, target);
        SET_SBIC_timeo(sc, SBIC_TIMEOUT(250, sc->sc_clkfreq));

        GET_SBIC_asr(sc, asr);
        if (asr & (SBIC_ASR_INT|SBIC_ASR_BSY)) {
                /* This means we got ourselves reselected upon */
                SBIC_DEBUG(PHASE, ("WD busy (reselect?) ASR=%02x\n", asr));
                return 0;
        }

        SET_SBIC_cmd(sc, SBIC_CMD_SEL_ATN);
        WAIT_CIP(sc);

        /*
         * wait for select (merged from separate function may need
         * cleanup)
         */
        do {
                asr = SBIC_WAIT(sc, SBIC_ASR_INT | SBIC_ASR_LCI, 0);
                if (asr & SBIC_ASR_LCI) {
                        QPRINTF(("late LCI: asr %02x\n", asr));
                        return 0;
                }

                /* Clear interrupt */
                GET_SBIC_csr (sc, csr);

                /* Reselected from under our feet? */
                if (csr == SBIC_CSR_RSLT_NI || csr == SBIC_CSR_RSLT_IFY) {
                        SBIC_DEBUG(PHASE, ("got reselected, asr %02x\n", asr));
                        /*
                         * We need to handle this now so we don't lock up later
                         */
                        wd33c93_nextstate(sc, acb, csr, asr);
                        return 0;
                }

                /* Whoops! */
                if (csr == SBIC_CSR_SLT || csr == SBIC_CSR_SLT_ATN) {
                        panic("wd33c93_selectbus: target issued select!");
                        return 0;
                }

        } while (csr != (SBIC_CSR_MIS_2 | MESG_OUT_PHASE) &&
                 csr != (SBIC_CSR_MIS_2 | CMD_PHASE) &&
                 csr != SBIC_CSR_SEL_TIMEO);

        /* Anyone at home? */
        if (csr == SBIC_CSR_SEL_TIMEO) {
                xs->error = XS_SELTIMEOUT;
                SBIC_DEBUG(PHASE, ("-- Selection Timeout\n"));
                return 0;
        }

        SBIC_DEBUG(PHASE, ("Selection Complete\n"));

        /* Assume we're now selected */
        GET_SBIC_selid(sc, id);
        if (id != target) {
                /* Something went wrong - wrong target was select */
                printf("wd33c93_selectbus: wrong target selected;"
                    "  WANTED %d GOT %d", target, id);
                return 0;      /* XXX: Need to call nexstate to handle? */
        }

        sc->sc_flags |= SBICF_SELECTED;
        sc->sc_state  = SBIC_CONNECTED;

        /* setup correct sync mode for this target */
        wd33c93_setsync(sc, ti);

        if (ti->flags & T_NODISC && sc->sc_disc == 0)
                SET_SBIC_rselid (sc, 0); /* Not expecting a reselect */
        else
                SET_SBIC_rselid (sc, SBIC_RID_ER);

        /*
         * We only really need to do anything when the target goes to MSG out
         * If the device ignored ATN, it's probably old and brain-dead,
         * but we'll try to support it anyhow.
         * If it doesn't support message out, it definitely doesn't
         * support synchronous transfers, so no point in even asking...
         */
        if (csr == (SBIC_CSR_MIS_2 | MESG_OUT_PHASE)) {
                if (ti->flags & T_NEGOTIATE) {
                        /* Initiate a SDTR message */
                        SBIC_DEBUG(SYNC, ("Sending SDTR to target %d\n", id));
                        if (ti->flags & T_WANTSYNC) {
                                ti->period = sc->sc_minsyncperiod;
                                ti->offset = sc->sc_maxoffset;
                        } else {
                                ti->period = 0;
                                ti->offset = 0;
                        }
                        /* Send Sync negotiation message */
                        sc->sc_omsg[0] = MSG_IDENTIFY(lun, 0); /* No Disc */
                        sc->sc_omsg[1] = MSG_EXTENDED;
                        sc->sc_omsg[2] = MSG_EXT_SDTR_LEN;
                        sc->sc_omsg[3] = MSG_EXT_SDTR;
                        if (ti->flags & T_WANTSYNC) {
                                sc->sc_omsg[4] = sc->sc_minsyncperiod;
                                sc->sc_omsg[5] = sc->sc_maxoffset;
                        } else {
                                sc->sc_omsg[4] = 0;
                                sc->sc_omsg[5] = 0;
                        }
                        wd33c93_xfout(sc, 6, sc->sc_omsg);
                        sc->sc_msgout |= SEND_SDTR; /* may be rejected */
                        sc->sc_flags  |= SBICF_SYNCNEGO;
                } else {
                        if (sc->sc_nexus->tag_type != 0) {
                                /* Use TAGS */
                                SBIC_DEBUG(TAGS, ("<select %d:%d TAG=%x>\n",
                                               sc->target, sc->lun,
                                               sc->sc_nexus->tag_id));
                                sc->sc_omsg[0] = MSG_IDENTIFY(lun, 1);
                                sc->sc_omsg[1] = sc->sc_nexus->tag_type;
                                sc->sc_omsg[2] = sc->sc_nexus->tag_id;
                                wd33c93_xfout(sc, 3, sc->sc_omsg);
                                sc->sc_msgout |= SEND_TAG;
                        } else {
                                int no_disc;

                                /* Setup LUN nexus and disconnect privilege */
                                no_disc = xs->xs_control & XS_CTL_POLL ||
                                          ti->flags & T_NODISC;
                                SEND_BYTE(sc, MSG_IDENTIFY(lun, !no_disc));
                        }
                }
                /*
                 * There's one interrupt still to come:
                 * the change to CMD phase...
                 */
                SBIC_WAIT(sc, SBIC_ASR_INT , 0);
                GET_SBIC_csr(sc, csr);
        }

        return csr;
}

/*
 * Information Transfer *to* a SCSI Target.
 *
 * Note: Don't expect there to be an interrupt immediately after all
 * the data is transferred out. The WD spec sheet says that the Transfer-
 * Info command for non-MSG_IN phases only completes when the target
 * next asserts 'REQ'. That is, when the SCSI bus changes to a new state.
 *
 * This can have a nasty effect on commands which take a relatively long
 * time to complete, for example a START/STOP unit command may remain in
 * CMD phase until the disk has spun up. Only then will the target change
 * to STATUS phase. This is really only a problem for immediate commands
 * since we don't allow disconnection for them (yet).
 */
int
wd33c93_xfout(struct wd33c93_softc *sc, int len, void *bp)
{
        int wait = wd33c93_data_wait;
        u_char asr, *buf = bp;

        QPRINTF(("wd33c93_xfout {%d} %02x %02x %02x %02x %02x "
                    "%02x %02x %02x %02x %02x\n", len, buf[0], buf[1], buf[2],
                    buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9]));

        /*
         * sigh.. WD-PROTO strikes again.. sending the command in one go
         * causes the chip to lock up if talking to certain (misbehaving?)
         * targets. Anyway, this procedure should work for all targets, but
         * it's slightly slower due to the overhead
         */

        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);
        SBIC_TC_PUT (sc, (unsigned)len);

        WAIT_CIP (sc);
        SET_SBIC_cmd (sc, SBIC_CMD_XFER_INFO);

        /*
         * Loop for each byte transferred
         */
        do {
                GET_SBIC_asr (sc, asr);

                if (asr & SBIC_ASR_DBR) {
                        if (len) {
                                SET_SBIC_data (sc, *buf);
                                buf++;
                                len--;
                        } else {
                                SET_SBIC_data (sc, 0);
                        }
                        wait = wd33c93_data_wait;
                }
        } while (len && (asr & SBIC_ASR_INT) == 0 && wait-- > 0);

        QPRINTF(("wd33c93_xfout done: %d bytes remaining (wait:%d)\n", len, wait));

        /*
         * Normally, an interrupt will be pending when this routing returns.
         */
        return(len);
}

/*
 * Information Transfer *from* a Scsi Target
 * returns # bytes left to read
 */
int
wd33c93_xfin(struct wd33c93_softc *sc, int len, void *bp)
{
        int     wait = wd33c93_data_wait;
        u_char  *buf = bp;
        u_char  asr;
#ifdef  DEBUG
        u_char  *obp = bp;
#endif
        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);
        SBIC_TC_PUT (sc, (unsigned)len);

        WAIT_CIP (sc);
        SET_SBIC_cmd (sc, SBIC_CMD_XFER_INFO);

        /*
         * Loop for each byte transferred
         */
        do {
                GET_SBIC_asr (sc, asr);

                if (asr & SBIC_ASR_DBR) {
                        if (len) {
                                GET_SBIC_data (sc, *buf);
                                buf++;
                                len--;
                        } else {
                                u_char foo;
                                GET_SBIC_data (sc, foo);
                                __USE(foo);
                        }
                        wait = wd33c93_data_wait;
                }

        } while ((asr & SBIC_ASR_INT) == 0 && wait-- > 0);

        QPRINTF(("wd33c93_xfin {%d} %02x %02x %02x %02x %02x %02x "
                    "%02x %02x %02x %02x\n", len, obp[0], obp[1], obp[2],
                    obp[3], obp[4], obp[5], obp[6], obp[7], obp[8], obp[9]));

        SBIC_TC_PUT (sc, 0);

        /*
         * this leaves with one csr to be read
         */
        return len;
}


/*
 * Finish SCSI xfer command:  After the completion interrupt from
 * a read/write operation, sequence through the final phases in
 * programmed i/o.
 */
void
wd33c93_xferdone(struct wd33c93_softc *sc)
{
        u_char  phase, csr;
        int     s;

        QPRINTF(("{"));
        s = splbio();

        /*
         * have the wd33c93 complete on its own
         */
        SBIC_TC_PUT(sc, 0);
        SET_SBIC_cmd_phase(sc, 0x46);
        SET_SBIC_cmd(sc, SBIC_CMD_SEL_ATN_XFER);

        do {
                SBIC_WAIT (sc, SBIC_ASR_INT, 0);
                GET_SBIC_csr (sc, csr);
                QPRINTF(("%02x:", csr));
        } while ((csr != SBIC_CSR_DISC) &&
                 (csr != SBIC_CSR_DISC_1) &&
                 (csr != SBIC_CSR_S_XFERRED));

        sc->sc_flags &= ~SBICF_SELECTED;
        sc->sc_state = SBIC_DISCONNECT;

        GET_SBIC_cmd_phase (sc, phase);
        QPRINTF(("}%02x", phase));

        if (phase == 0x60)
                GET_SBIC_tlun(sc, sc->sc_status);
        else
                wd33c93_error(sc, sc->sc_nexus, "unexpected phase");

        QPRINTF(("=STS:%02x=\n", sc->sc_status));
        splx(s);
}


int
wd33c93_go(struct wd33c93_softc *sc, struct wd33c93_acb *acb)
{
        struct scsipi_xfer      *xs = acb->xs;
        int                     i, dmaok;
        u_char                  csr, asr;

        SBIC_DEBUG(ACBS, ("wd33c93_go(%d:%d)\n", sc->target, sc->lun));

        sc->sc_nexus = acb;

        sc->target = xs->xs_periph->periph_target;
        sc->lun    = xs->xs_periph->periph_lun;

        sc->sc_status = STATUS_UNKNOWN;
        sc->sc_daddr = acb->daddr;
        sc->sc_dleft = acb->dleft;

        sc->sc_msgpriq = sc->sc_msgout = sc->sc_msgoutq = 0;
        sc->sc_flags = 0;

        dmaok = wd33c93_dmaok(sc, xs);

        if (dmaok == 0)
                sc->sc_flags |= SBICF_NODMA;

        SBIC_DEBUG(DMA, ("wd33c93_go dmago:%d(tcnt=%zx) dmaok=%dx\n",
                       sc->target, sc->sc_tcnt, dmaok));

        /* select the SCSI bus (it's an error if bus isn't free) */
        if ((csr = wd33c93_selectbus(sc, acb)) == 0)
                return(0); /* Not done: needs to be rescheduled */

        /*
         * Lets cycle a while then let the interrupt handler take over.
         */
        GET_SBIC_asr(sc, asr);
        do {
                QPRINTF(("go[0x%x] ", csr));

                /* Handle the new phase */
                i = wd33c93_nextstate(sc, acb, csr, asr);
                WAIT_CIP(sc);           /* XXX */
                if (sc->sc_state == SBIC_CONNECTED) {

                        GET_SBIC_asr(sc, asr);

                        if (asr & SBIC_ASR_LCI)
                                printf("wd33c93_go: LCI asr:%02x csr:%02x\n", asr, csr);

                        if (asr & SBIC_ASR_INT)
                                GET_SBIC_csr(sc, csr);
                }

        } while (sc->sc_state == SBIC_CONNECTED &&
                 asr & (SBIC_ASR_INT|SBIC_ASR_LCI));

        QPRINTF(("> done i=%d stat=%02x\n", i, sc->sc_status));

        if (i == SBIC_STATE_DONE) {
                if (sc->sc_status == STATUS_UNKNOWN) {
                        printf("wd33c93_go: done & stat == UNKNOWN\n");
                        return 1;  /* Did we really finish that fast? */
                }
        }
        return 0;
}


int
wd33c93_intr(struct wd33c93_softc *sc)
{
        u_char  asr, csr;

        /*
         * pending interrupt?
         */
        GET_SBIC_asr (sc, asr);
        if ((asr & SBIC_ASR_INT) == 0)
                return(0);

        GET_SBIC_csr(sc, csr);

        do {
                SBIC_DEBUG(INTS, ("intr[csr=0x%x]", csr));

                (void)wd33c93_nextstate(sc, sc->sc_nexus, csr, asr);
                WAIT_CIP(sc);           /* XXX */
                if (sc->sc_state == SBIC_CONNECTED) {
                        GET_SBIC_asr(sc, asr);

                        if (asr & SBIC_ASR_LCI)
                                printf("wd33c93_intr: LCI asr:%02x csr:%02x\n",
                                    asr, csr);

                        if (asr & SBIC_ASR_INT)
                                GET_SBIC_csr(sc, csr);
                }
        } while (sc->sc_state == SBIC_CONNECTED &&
                 asr & (SBIC_ASR_INT|SBIC_ASR_LCI));

       SBIC_DEBUG(INTS, ("intr done. state=%d, asr=0x%02x\n",
           sc->sc_state, asr));

        return(1);
}

/*
 * Complete current command using polled I/O.   Used when interrupt driven
 * I/O is not allowed (ie. during boot and shutdown)
 *
 * Polled I/O is very processor intensive
 */
int
wd33c93_poll(struct wd33c93_softc *sc, struct wd33c93_acb *acb)
{
        u_char                  asr, csr=0;
        int                     count;
        struct scsipi_xfer      *xs = acb->xs;

        SBIC_WAIT(sc, SBIC_ASR_INT, wd33c93_cmd_wait);
        for (count=acb->timeout; count;) {
                GET_SBIC_asr (sc, asr);
                if (asr & SBIC_ASR_LCI)
                        printf("wd33c93_poll: LCI; asr:%02x csr:%02x\n",
                            asr, csr);
                if (asr & SBIC_ASR_INT) {
                        GET_SBIC_csr(sc, csr);
                        sc->sc_flags |= SBICF_NODMA;
                        (void)wd33c93_nextstate(sc, sc->sc_nexus, csr, asr);
                        WAIT_CIP(sc);           /* XXX */
                } else {
                        DELAY(1000);
                        count--;
                }

                if ((xs->xs_status & XS_STS_DONE) != 0)
                        return (0);

                if (sc->sc_state == SBIC_IDLE) {
                        SBIC_DEBUG(ACBS, ("[poll: rescheduling] "));
                        wd33c93_sched(sc);
                }
        }
        return (1);
}

static inline int
__verify_msg_format(u_char *p, int len)
{

        if (len == 1 && MSG_IS1BYTE(p[0]))
                return 1;
        if (len == 2 && MSG_IS2BYTE(p[0]))
                return 1;
        if (len >= 3 && MSG_ISEXTENDED(p[0]) &&
            len == p[1] + 2)
                return 1;
        return 0;
}

/*
 * Handle message_in phase
 */
int
wd33c93_msgin_phase(struct wd33c93_softc *sc, int reselect)
{
        int len;
        u_char asr, csr, *msg;

        GET_SBIC_asr(sc, asr);
        __USE(asr);

        SBIC_DEBUG(MSGS, ("wd33c93msgin asr=%02x\n", asr));

        GET_SBIC_selid (sc, csr);
        SET_SBIC_selid (sc, csr | SBIC_SID_FROM_SCSI);

        SBIC_TC_PUT(sc, 0);

        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);

        msg = sc->sc_imsg;
        len = 0;

        do {
                /* Fetch the next byte of the message */
                RECV_BYTE(sc, *msg++);
                len++;

                /*
                 * get the command completion interrupt, or we
                 * can't send a new command (LCI)
                 */
                SBIC_WAIT(sc, SBIC_ASR_INT, 0);
                GET_SBIC_csr(sc, csr);

                if (__verify_msg_format(sc->sc_imsg, len))
                        break; /* Complete message received */

                /*
                 * Clear ACK, and wait for the interrupt
                 * for the next byte or phase change
                 */
                SET_SBIC_cmd(sc, SBIC_CMD_CLR_ACK);
                SBIC_WAIT(sc, SBIC_ASR_INT, 0);

                GET_SBIC_csr(sc, csr);
        } while (len < SBIC_MAX_MSGLEN);

        if (__verify_msg_format(sc->sc_imsg, len))
                wd33c93_msgin(sc, sc->sc_imsg, len);

        /*
         * Clear ACK, and wait for the interrupt
         * for the phase change
         */
        SET_SBIC_cmd(sc, SBIC_CMD_CLR_ACK);
        SBIC_WAIT(sc, SBIC_ASR_INT, 0);

        /* Should still have one CSR to read */
        return SBIC_STATE_RUNNING;
}


void wd33c93_msgin(struct wd33c93_softc *sc, u_char *msgaddr, int msglen)
{
        struct wd33c93_acb    *acb = sc->sc_nexus;
        struct wd33c93_tinfo  *ti = &sc->sc_tinfo[sc->target];
        struct wd33c93_linfo  *li;
        u_char asr;

        switch (sc->sc_state) {
        case SBIC_CONNECTED:
                switch (msgaddr[0]) {
                case MSG_MESSAGE_REJECT:
                        SBIC_DEBUG(MSGS, ("msgin: MSG_REJECT, "
                                       "last msgout=%x\n", sc->sc_msgout));
                        switch (sc->sc_msgout) {
                        case SEND_TAG:
                                printf("%s: tagged queuing rejected: "
                                    "target %d\n",
                                    device_xname(sc->sc_dev), sc->target);
                                ti->flags &= ~T_TAG;
                                li = TINFO_LUN(ti, sc->lun);
                                if (acb->tag_type &&
                                    li->queued[acb->tag_id] != NULL) {
                                        li->queued[acb->tag_id] = NULL;
                                        li->used--;
                                }
                                acb->tag_type = acb->tag_id = 0;
                                li->untagged = acb;
                                li->state = L_STATE_BUSY;
                                break;

                        case SEND_SDTR:
                                printf("%s: sync transfer rejected: target %d\n",
                                    device_xname(sc->sc_dev), sc->target);

                                sc->sc_flags &= ~SBICF_SYNCNEGO;
                                ti->flags &= ~(T_NEGOTIATE | T_SYNCMODE);
                                wd33c93_update_xfer_mode(sc,
                                    acb->xs->xs_periph->periph_target);
                                wd33c93_setsync(sc, ti);

                        case SEND_INIT_DET_ERR:
                                goto abort;

                        default:
                                SBIC_DEBUG(MSGS, ("Unexpected MSG_REJECT\n"));
                                break;
                        }
                        sc->sc_msgout = 0;
                        break;

                case MSG_HEAD_OF_Q_TAG:
                case MSG_ORDERED_Q_TAG:
                case MSG_SIMPLE_Q_TAG:
                        printf("-- Out of phase TAG;"
                            "Nexus=%d:%d Tag=%02x/%02x\n",
                            sc->target, sc->lun, msgaddr[0], msgaddr[1]);
                        break;

                case MSG_DISCONNECT:
                        SBIC_DEBUG(MSGS, ("msgin: DISCONNECT"));
                        /*
                         * Mark the fact that all bytes have moved. The
                         * target may not bother to do a SAVE POINTERS
                         * at this stage. This flag will set the residual
                         * count to zero on MSG COMPLETE.
                         */
                        if (sc->sc_dleft == 0)
                                acb->flags |= ACB_COMPLETE;

                        if (acb->xs->xs_control & XS_CTL_POLL)
                                /* Don't allow disconnect in immediate mode */
                                goto reject;
                        else {  /* Allow disconnect */
                                sc->sc_flags &= ~SBICF_SELECTED;
                                sc->sc_state = SBIC_DISCONNECT;
                        }
                        if ((acb->xs->xs_periph->periph_quirks &
                                PQUIRK_AUTOSAVE) == 0)
                                break;
                        /*FALLTHROUGH*/

                case MSG_SAVEDATAPOINTER:
                        SBIC_DEBUG(MSGS, ("msgin: SAVEDATAPTR"));
                        acb->daddr = sc->sc_daddr;
                        acb->dleft = sc->sc_dleft;
                        break;

                case MSG_RESTOREPOINTERS:
                        SBIC_DEBUG(MSGS, ("msgin: RESTOREPTR"));
                        sc->sc_daddr = acb->daddr;
                        sc->sc_dleft = acb->dleft;
                        break;

                case MSG_CMDCOMPLETE:
                        /*
                         * !! KLUDGE ALERT !! quite a few drives don't seem to
                         * really like the current way of sending the
                         * sync-handshake together with the ident-message, and
                         * they react by sending command-complete and
                         * disconnecting right after returning the valid sync
                         * handshake. So, all I can do is reselect the drive,
                         * and hope it won't disconnect again. I don't think
                         * this is valid behavior, but I can't help fixing a
                         * problem that apparently exists.
                         *
                         * Note: we should not get here on `normal' command
                         * completion, as that condition is handled by the
                         * high-level sel&xfer resume command used to walk
                         * thru status/cc-phase.
                         */
                        SBIC_DEBUG(MSGS, ("msgin: CMD_COMPLETE"));
                        SBIC_DEBUG(SYNC, ("GOT MSG %d! target %d"
                                       " acting weird.."
                                       " waiting for disconnect...\n",
                                       msgaddr[0], sc->target));

                        /* Check to see if wd33c93 is handling this */
                        GET_SBIC_asr(sc, asr);
                        if (asr & SBIC_ASR_BSY)
                                break;

                        /* XXX: Assume it works and set status to 00 */
                        sc->sc_status = 0;
                        sc->sc_state = SBIC_CMDCOMPLETE;
                        break;

                case MSG_EXTENDED:
                        switch(msgaddr[2]) {
                        case MSG_EXT_SDTR: /* Sync negotiation */
                                SBIC_DEBUG(MSGS, ("msgin: EXT_SDTR; "
                                               "period %d, offset %d",
                                               msgaddr[3], msgaddr[4]));
                                if (msgaddr[1] != 3)
                                        goto reject;

                                ti->period =
                                    MAX(msgaddr[3], sc->sc_minsyncperiod);
                                ti->offset = MIN(msgaddr[4], sc->sc_maxoffset);

                                /*
                                 * <SGI, IBM DORS-32160, WA6A> will do nothing
                                 * but attempt sync negotiation until it gets
                                 * what it wants. To avoid an infinite loop set
                                 * off by the identify request, oblige them.
                                 */
                                if ((sc->sc_flags&SBICF_SYNCNEGO) == 0 &&
                                    msgaddr[3] != 0)
                                        ti->flags |= T_WANTSYNC;

                                if (!(ti->flags & T_WANTSYNC))
                                        ti->period = ti->offset = 0;

                                ti->flags &= ~T_NEGOTIATE;

                                if (ti->offset == 0)
                                        ti->flags &= ~T_SYNCMODE; /* Async */
                                else
                                        ti->flags |= T_SYNCMODE; /* Sync */

                                /* target initiated negotiation */
                                if ((sc->sc_flags&SBICF_SYNCNEGO) == 0)
                                        wd33c93_sched_msgout(sc, SEND_SDTR);
                                sc->sc_flags &= ~SBICF_SYNCNEGO;

                                SBIC_DEBUG(SYNC, ("msgin(%d): SDTR(o=%d,p=%d)",
                                               sc->target, ti->offset,
                                               ti->period));
                                wd33c93_update_xfer_mode(sc,
                                    acb->xs->xs_periph->periph_target);
                                wd33c93_setsync(sc, ti);
                                break;

                        case MSG_EXT_WDTR:
                                SBIC_DEBUG(MSGS, ("msgin: EXT_WDTR rejected"));
                                goto reject;

                        default:
                                scsipi_printaddr(acb->xs->xs_periph);
                                printf("unrecognized MESSAGE EXTENDED;"
                                    " sending REJECT\n");
                                goto reject;
                        }
                        break;

                default:
                        scsipi_printaddr(acb->xs->xs_periph);
                        printf("unrecognized MESSAGE; sending REJECT\n");

                reject:
                        /* We don't support whatever this message is... */
                        wd33c93_sched_msgout(sc, SEND_REJECT);
                        break;
                }
                break;

        case SBIC_IDENTIFIED:
                /*
                 * IDENTIFY message was received and queue tag is expected now
                 */
                if ((msgaddr[0]!=MSG_SIMPLE_Q_TAG) || (sc->sc_msgify==0)) {
                        printf("%s: TAG reselect without IDENTIFY;"
                            " MSG %x; sending DEVICE RESET\n",
                            device_xname(sc->sc_dev), msgaddr[0]);
                        goto reset;
                }
                SBIC_DEBUG(TAGS, ("TAG %x/%x\n", msgaddr[0], msgaddr[1]));
                if (sc->sc_nexus)
                        printf("*TAG Recv with active nexus!!\n");
                wd33c93_reselect(sc, sc->target, sc->lun,
                              msgaddr[0], msgaddr[1]);
                break;

        case SBIC_RESELECTED:
                /*
                 * IDENTIFY message with target
                 */
                if (MSG_ISIDENTIFY(msgaddr[0])) {
                        SBIC_DEBUG(PHASE, ("IFFY[%x] ", msgaddr[0]));
                        sc->sc_msgify = msgaddr[0];
                } else {
                        printf("%s: reselect without IDENTIFY;"
                            " MSG %x;"
                            " sending DEVICE RESET\n",
                            device_xname(sc->sc_dev), msgaddr[0]);
                        goto reset;
                }
                break;

        default:
                printf("Unexpected MESSAGE IN.  State=%d - Sending RESET\n",
                    sc->sc_state);
        reset:
                wd33c93_sched_msgout(sc, SEND_DEV_RESET);
                break;
        abort:
                wd33c93_sched_msgout(sc, SEND_ABORT);
                break;
        }
}

void
wd33c93_sched_msgout(struct wd33c93_softc *sc, u_short msg)
{
        u_char  asr;

        SBIC_DEBUG(SYNC,("sched_msgout: %04x\n", msg));
        sc->sc_msgpriq |= msg;

        /* Schedule MSGOUT Phase to send message */

        WAIT_CIP(sc);
        SET_SBIC_cmd(sc, SBIC_CMD_SET_ATN);
        WAIT_CIP(sc);
        GET_SBIC_asr(sc, asr);
        if (asr & SBIC_ASR_LCI) {
                printf("MSGOUT Failed!\n");
        }
        SET_SBIC_cmd(sc, SBIC_CMD_CLR_ACK);
        WAIT_CIP(sc);
}

/*
 * Send the highest priority, scheduled message
 */
void
wd33c93_msgout(struct wd33c93_softc *sc)
{
        struct wd33c93_tinfo *ti;
        struct wd33c93_acb *acb = sc->sc_nexus;

        if (acb == NULL)
                panic("MSGOUT with no nexus");

        if (sc->sc_omsglen == 0) {
                /* Pick up highest priority message */
                sc->sc_msgout   = sc->sc_msgpriq & -sc->sc_msgpriq;
                sc->sc_msgoutq |= sc->sc_msgout;
                sc->sc_msgpriq &= ~sc->sc_msgout;
                sc->sc_omsglen = 1;             /* "Default" message len */
                switch (sc->sc_msgout) {
                case SEND_SDTR:
                        ti = &sc->sc_tinfo[acb->xs->xs_periph->periph_target];
                        sc->sc_omsg[0] = MSG_EXTENDED;
                        sc->sc_omsg[1] = MSG_EXT_SDTR_LEN;
                        sc->sc_omsg[2] = MSG_EXT_SDTR;
                        if (ti->flags & T_WANTSYNC) {
                                sc->sc_omsg[3] = ti->period;
                                sc->sc_omsg[4] = ti->offset;
                        } else {
                                sc->sc_omsg[3] = 0;
                                sc->sc_omsg[4] = 0;
                        }
                        sc->sc_omsglen = 5;
                        if ((sc->sc_flags & SBICF_SYNCNEGO) == 0) {
                                if (ti->flags & T_WANTSYNC)
                                        ti->flags |= T_SYNCMODE;
                                else
                                        ti->flags &= ~T_SYNCMODE;
                                wd33c93_setsync(sc, ti);
                        }
                        break;
                case SEND_IDENTIFY:
                        if (sc->sc_state != SBIC_CONNECTED) {
                                printf("%s at line %d: no nexus\n",
                                    device_xname(sc->sc_dev), __LINE__);
                        }
                        sc->sc_omsg[0] =
                            MSG_IDENTIFY(acb->xs->xs_periph->periph_lun, 0);
                        break;
                case SEND_TAG:
                        if (sc->sc_state != SBIC_CONNECTED) {
                                printf("%s at line %d: no nexus\n",
                                    device_xname(sc->sc_dev), __LINE__);
                        }
                        sc->sc_omsg[0] = acb->tag_type;
                        sc->sc_omsg[1] = acb->tag_id;
                        sc->sc_omsglen = 2;
                        break;
                case SEND_DEV_RESET:
                        sc->sc_omsg[0] = MSG_BUS_DEV_RESET;
                        ti = &sc->sc_tinfo[sc->target];
                        ti->flags &= ~T_SYNCMODE;
                        wd33c93_update_xfer_mode(sc, sc->target);
                        if ((ti->flags & T_NOSYNC) == 0)
                                /* We can re-start sync negotiation */
                                ti->flags |= T_NEGOTIATE;
                        break;
                case SEND_PARITY_ERROR:
                        sc->sc_omsg[0] = MSG_PARITY_ERROR;
                        break;
                case SEND_ABORT:
                        sc->sc_flags  |= SBICF_ABORTING;
                        sc->sc_omsg[0] = MSG_ABORT;
                        break;
                case SEND_INIT_DET_ERR:
                        sc->sc_omsg[0] = MSG_INITIATOR_DET_ERR;
                        break;
                case SEND_REJECT:
                        sc->sc_omsg[0] = MSG_MESSAGE_REJECT;
                        break;
                default:
                        /* Wasn't expecting MSGOUT Phase */
                        sc->sc_omsg[0] = MSG_NOOP;
                        break;
                }
        }

        wd33c93_xfout(sc, sc->sc_omsglen, sc->sc_omsg);
}


/*
 * wd33c93_nextstate()
 * return:
 *      SBIC_STATE_DONE         == done
 *      SBIC_STATE_RUNNING      == working
 *      SBIC_STATE_DISCONNECT   == disconnected
 *      SBIC_STATE_ERROR        == error
 */
int
wd33c93_nextstate(struct wd33c93_softc *sc, struct wd33c93_acb  *acb, u_char csr, u_char asr)
{
        SBIC_DEBUG(PHASE, ("next[a=%02x,c=%02x]: ",asr,csr));

        switch (csr) {

        case SBIC_CSR_XFERRED | CMD_PHASE:
        case SBIC_CSR_MIS     | CMD_PHASE:
        case SBIC_CSR_MIS_1   | CMD_PHASE:
        case SBIC_CSR_MIS_2   | CMD_PHASE:

                if (wd33c93_xfout(sc, acb->clen, &acb->cmd))
                        goto abort;
                break;

        case SBIC_CSR_XFERRED | STATUS_PHASE:
        case SBIC_CSR_MIS     | STATUS_PHASE:
        case SBIC_CSR_MIS_1   | STATUS_PHASE:
        case SBIC_CSR_MIS_2   | STATUS_PHASE:

                SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);

                /*
                 * this should be the normal i/o completion case.
                 * get the status & cmd complete msg then let the
                 * device driver look at what happened.
                 */
                wd33c93_xferdone(sc);

                wd33c93_dma_stop(sc);

                /* Fixup byte count to be passed to higher layer */
                acb->dleft = (acb->flags & ACB_COMPLETE) ? 0 :
                              sc->sc_dleft;

                /*
                 * Indicate to the upper layers that the command is done
                 */
                wd33c93_scsidone(sc, acb, sc->sc_status);

                return SBIC_STATE_DONE;


        case SBIC_CSR_XFERRED | DATA_IN_PHASE:
        case SBIC_CSR_MIS     | DATA_IN_PHASE:
        case SBIC_CSR_MIS_1   | DATA_IN_PHASE:
        case SBIC_CSR_MIS_2   | DATA_IN_PHASE:
        case SBIC_CSR_XFERRED | DATA_OUT_PHASE:
        case SBIC_CSR_MIS     | DATA_OUT_PHASE:
        case SBIC_CSR_MIS_1   | DATA_OUT_PHASE:
        case SBIC_CSR_MIS_2   | DATA_OUT_PHASE:
                /*
                 * Verify that we expected to transfer data...
                 */
                if (acb->dleft <= 0) {
                        printf("next: DATA phase with xfer count == %zd, asr:0x%02x csr:0x%02x\n",
                            acb->dleft, asr, csr);
                        goto abort;
                }

                /*
                 * Should we transfer using PIO or DMA ?
                 */
                if (acb->xs->xs_control & XS_CTL_POLL ||
                    sc->sc_flags & SBICF_NODMA) {
                        /* Perform transfer using PIO */
                        int resid;

                        SBIC_DEBUG(DMA, ("PIO xfer: %d(%p:%zx)\n", sc->target,
                                       sc->sc_daddr, sc->sc_dleft));

                        if (SBIC_PHASE(csr) == DATA_IN_PHASE)
                                /* data in */
                                resid = wd33c93_xfin(sc, sc->sc_dleft,
                                                 sc->sc_daddr);
                        else    /* data out */
                                resid = wd33c93_xfout(sc, sc->sc_dleft,
                                                  sc->sc_daddr);

                        sc->sc_daddr = (char *)sc->sc_daddr +
                                (acb->dleft - resid);
                        sc->sc_dleft = resid;
                } else {
                        int datain = SBIC_PHASE(csr) == DATA_IN_PHASE;

                        /* Perform transfer using DMA */
                        wd33c93_dma_setup(sc, datain);

                        SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI |
                            sc->sc_dmamode);

                        SBIC_DEBUG(DMA, ("DMA xfer: %d(%p:%zx)\n", sc->target,
                                       sc->sc_daddr, sc->sc_dleft));

                        /* Setup byte count for transfer */
                        SBIC_TC_PUT(sc, (unsigned)sc->sc_dleft);

                        /* Start the transfer */
                        SET_SBIC_cmd(sc, SBIC_CMD_XFER_INFO);

                        /* Start the DMA chip going */
                        sc->sc_tcnt = sc->sc_dmago(sc);

                        /* Indicate that we're in DMA mode */
                        sc->sc_flags |= SBICF_INDMA;
                }
                break;

        case SBIC_CSR_XFERRED | MESG_IN_PHASE:
        case SBIC_CSR_MIS     | MESG_IN_PHASE:
        case SBIC_CSR_MIS_1   | MESG_IN_PHASE:
        case SBIC_CSR_MIS_2   | MESG_IN_PHASE:

                wd33c93_dma_stop(sc);

                /* Handle a single message in... */
                return wd33c93_msgin_phase(sc, 0);

        case SBIC_CSR_MSGIN_W_ACK:

                /*
                 * We should never see this since it's handled in
                 * 'wd33c93_msgin_phase()' but just for the sake of paranoia...
                 */
                SET_SBIC_cmd(sc, SBIC_CMD_CLR_ACK);

                printf("Acking unknown msgin CSR:%02x",csr);
                break;

        case SBIC_CSR_XFERRED | MESG_OUT_PHASE:
        case SBIC_CSR_MIS     | MESG_OUT_PHASE:
        case SBIC_CSR_MIS_1   | MESG_OUT_PHASE:
        case SBIC_CSR_MIS_2   | MESG_OUT_PHASE:

                /*
                 * Message out phase.  ATN signal has been asserted
                 */
                wd33c93_dma_stop(sc);
                wd33c93_msgout(sc);
                return SBIC_STATE_RUNNING;

        case SBIC_CSR_DISC:
        case SBIC_CSR_DISC_1:
                SBIC_DEBUG(RSEL, ("wd33c93next target %d disconnected\n",
                               sc->target));
                wd33c93_dma_stop(sc);

                sc->sc_nexus = NULL;
                sc->sc_state = SBIC_IDLE;
                sc->sc_flags = 0;

                ++sc->sc_tinfo[sc->target].dconns;
                ++sc->sc_disc;

                if (acb->xs->xs_control & XS_CTL_POLL || wd33c93_nodisc)
                        return SBIC_STATE_DISCONNECT;

                /* Try to schedule another target */
                wd33c93_sched(sc);

                return SBIC_STATE_DISCONNECT;

        case SBIC_CSR_RSLT_NI:
        case SBIC_CSR_RSLT_IFY:
        {
                /*
                 * A reselection.
                 * Note that since we don't enable Advanced Features (assuming
                 * the WD chip is at least the 'A' revision), we're only ever
                 * likely to see the 'SBIC_CSR_RSLT_NI' status. But for the
                 * hell of it, we'll handle it anyway, for all the extra code
                 * it needs...
                 */
                u_char  newtarget, newlun;

                if (sc->sc_flags & SBICF_INDMA) {
                        printf("**** RESELECT WHILE DMA ACTIVE!!! ***\n");
                        wd33c93_dma_stop(sc);
                }

                sc->sc_state = SBIC_RESELECTED;
                GET_SBIC_rselid(sc, newtarget);

                /* check SBIC_RID_SIV? */
                newtarget &= SBIC_RID_MASK;

                if (csr == SBIC_CSR_RSLT_IFY) {
                        /* Read Identify msg to avoid lockup */
                        GET_SBIC_data(sc, newlun);
                        WAIT_CIP(sc);
                        newlun &= SBIC_TLUN_MASK;
                        sc->sc_msgify = MSG_IDENTIFY(newlun, 0);
                } else {
                        /*
                         * Need to read Identify message the hard way, assuming
                         * the target even sends us one...
                         */
                        for (newlun = 255; newlun; --newlun) {
                                GET_SBIC_asr(sc, asr);
                                if (asr & SBIC_ASR_INT)
                                        break;
                                DELAY(10);
                        }

                        /* If we didn't get an interrupt, something's up */
                        if ((asr & SBIC_ASR_INT) == 0) {
                                printf("%s: Reselect without identify? asr %x\n",
                                    device_xname(sc->sc_dev), asr);
                                newlun = 0; /* XXXX */
                        } else {
                                /*
                                 * We got an interrupt, verify that it's a
                                 * change to message in phase, and if so
                                 * read the message.
                                 */
                                GET_SBIC_csr(sc,csr);

                                if (csr == (SBIC_CSR_MIS   | MESG_IN_PHASE) ||
                                    csr == (SBIC_CSR_MIS_1 | MESG_IN_PHASE) ||
                                    csr == (SBIC_CSR_MIS_2 | MESG_IN_PHASE)) {
                                        /*
                                         * Yup, gone to message in.
                                         * Fetch the target LUN
                                         */
                                        sc->sc_msgify = 0;
                                        wd33c93_msgin_phase(sc, 1);
                                        newlun = sc->sc_msgify & SBIC_TLUN_MASK;
                                } else {
                                        /*
                                         * Whoops! Target didn't go to msg_in
                                         * phase!!
                                         */
                                        printf("RSLT_NI - not MESG_IN_PHASE %x\n", csr);
                                        newlun = 0; /* XXXSCW */
                                }
                        }
                }

                /* Ok, we have the identity of the reselecting target. */
                SBIC_DEBUG(RSEL, ("wd33c93next: reselect from targ %d lun %d",
                               newtarget, newlun));
                wd33c93_reselect(sc, newtarget, newlun, 0, 0);
                sc->sc_disc--;

                if (csr == SBIC_CSR_RSLT_IFY)
                        SET_SBIC_cmd(sc, SBIC_CMD_CLR_ACK);
                break;
        }

        default:
        abort:
                /* Something unexpected happened -- deal with it. */
                printf("next: aborting asr 0x%02x csr 0x%02x\n", asr, csr);

#ifdef DDB
                Debugger();
#endif

                SET_SBIC_control(sc, SBIC_CTL_EDI | SBIC_CTL_IDI);
                if (acb->xs)
                        wd33c93_error(sc, acb, "unexpected/abort");
                wd33c93_abort(sc, acb, "next");

                if (sc->sc_flags & SBICF_INDMA) {
                        wd33c93_dma_stop(sc);
                        wd33c93_scsidone(sc, acb, STATUS_UNKNOWN);
                }
                return SBIC_STATE_ERROR;
        }
        return SBIC_STATE_RUNNING;
}


void
wd33c93_reselect(struct wd33c93_softc *sc, int target, int lun, int tag_type, int tag_id)
{

        struct wd33c93_tinfo *ti;
        struct wd33c93_linfo *li;
        struct wd33c93_acb *acb;

        if (sc->sc_nexus) {
                /*
                 * Whoops! We've been reselected with a
                 * command in progress!
                 * The best we can do is to put the current
                 * command back on the ready list and hope
                 * for the best.
                 */
                SBIC_DEBUG(RSEL, ("%s: reselect with active command\n",
                               device_xname(sc->sc_dev)));
                ti = &sc->sc_tinfo[sc->target];
                li = TINFO_LUN(ti, sc->lun);
                li->state = L_STATE_IDLE;

                wd33c93_dequeue(sc, sc->sc_nexus);
                TAILQ_INSERT_HEAD(&sc->ready_list, sc->sc_nexus, chain);
                sc->sc_nexus->flags |= ACB_READY;

                sc->sc_nexus = NULL;
        }

        /* Setup state for new nexus */
        acb = NULL;
        sc->sc_flags = SBICF_SELECTED;
        sc->sc_msgpriq = sc->sc_msgout = sc->sc_msgoutq = 0;

        ti = &sc->sc_tinfo[target];
        li = TINFO_LUN(ti, lun);

        if (li != NULL) {
                if (li->untagged != NULL && li->state)
                        acb = li->untagged;
                else if (tag_type != MSG_SIMPLE_Q_TAG) {
                        /* Wait for tag to come by during MESG_IN Phase */
                        sc->target    = target; /* setup I_T_L nexus */
                        sc->lun       = lun;
                        sc->sc_state  = SBIC_IDENTIFIED;
                        return;
                } else if (tag_type)
                        acb = li->queued[tag_id];
        }

        if (acb == NULL) {
                printf("%s: reselect from target %d lun %d tag %x:%x "
                    "with no nexus; sending ABORT\n",
                    device_xname(sc->sc_dev), target, lun, tag_type, tag_id);
                goto abort;
        }

        sc->target    = target;
        sc->lun       = lun;
        sc->sc_nexus  = acb;
        sc->sc_state  = SBIC_CONNECTED;

        if (!wd33c93_dmaok(sc, acb->xs))
                sc->sc_flags |= SBICF_NODMA;

        /* Do an implicit RESTORE POINTERS. */
        sc->sc_daddr = acb->daddr;
        sc->sc_dleft = acb->dleft;

        /* Set sync modes for new target */
        wd33c93_setsync(sc, ti);

        if (acb->flags & ACB_RESET)
                wd33c93_sched_msgout(sc, SEND_DEV_RESET);
        else if (acb->flags & ACB_ABORT)
                wd33c93_sched_msgout(sc, SEND_ABORT);
        return;

abort:
        wd33c93_sched_msgout(sc, SEND_ABORT);
        return;

}

void
wd33c93_update_xfer_mode(struct wd33c93_softc *sc, int target)
{
        struct wd33c93_tinfo *ti = &sc->sc_tinfo[target];
        struct scsipi_xfer_mode xm;

        xm.xm_target = target;
        xm.xm_mode = 0;
        xm.xm_period = 0;
        xm.xm_offset = 0;

        if (ti->flags & T_SYNCMODE) {
                xm.xm_mode |= PERIPH_CAP_SYNC;
                xm.xm_period = ti->period;
                xm.xm_offset = ti->offset;
        }

        if ((ti->flags & (T_NODISC|T_TAG)) == T_TAG)
                xm.xm_mode |= PERIPH_CAP_TQING;

        SBIC_DEBUG(SYNC, ("wd33c93_update_xfer_mode: reporting target %d %s\n",
                       xm.xm_target,
                       (xm.xm_mode & PERIPH_CAP_SYNC) ? "sync" : "async"));

        scsipi_async_event(&sc->sc_channel, ASYNC_EVENT_XFER_MODE, &xm);
}

void
wd33c93_timeout_callout(void *arg)
{
        struct wd33c93_acb *acb = arg;
        int x;

        x = splbio();
        wd33c93_timeout(acb);
        splx(x);
}

/**
 * @brief Handle timeout events.
 *
 * Note: this can be run from outside splbio(), it will acquire it as needed.
 *
 * Returns 1 if the transfer was aborted and the caller should
 * reschedule or complete the acb, 0 otherwise.
 */
int
wd33c93_timeout(struct wd33c93_acb *acb)
{
        struct scsipi_xfer *xs = acb->xs;
        struct scsipi_periph *periph = xs->xs_periph;
        struct wd33c93_softc *sc =
            device_private(periph->periph_channel->chan_adapter->adapt_dev);
        int s, asr;
        int ret;

        s = splbio();

        GET_SBIC_asr(sc, asr);

        scsipi_printaddr(periph);
        printf("%s: timed out; asr=0x%02x [acb %p (flags 0x%x, dleft %zx)], "
            "<state %d, nexus %p, resid %lx, msg(q %x,o %x)>",
            device_xname(sc->sc_dev), asr, acb, acb->flags, acb->dleft,
            sc->sc_state, sc->sc_nexus, (long)sc->sc_dleft,
            sc->sc_msgpriq, sc->sc_msgout);

        if (asr & SBIC_ASR_INT) {
                /* We need to service a missed IRQ */
                wd33c93_intr(sc);
                ret = 0;
        } else {
                (void) wd33c93_abort(sc, acb, "timeout");
                ret = 1;
        }
        splx(s);

        return (ret);
}


void
wd33c93_watchdog(void *arg)
{
        struct wd33c93_softc *sc = arg;
        struct wd33c93_tinfo *ti;
        struct wd33c93_linfo *li;
        int t, s, l;
        /* scrub LUN's that have not been used in the last 10min. */
        time_t old = time_second - (10 * 60);

        for (t = 0; t < SBIC_NTARG; t++) {
                ti = &sc->sc_tinfo[t];
                for (l = 0; l < SBIC_NLUN; l++) {
                        s = splbio();
                        li = TINFO_LUN(ti, l);
                        if (li && li->last_used < old &&
                            li->untagged == NULL && li->used == 0) {
                                ti->lun[li->lun] = NULL;
                                free(li, M_DEVBUF);
                        }
                        splx(s);
                }
        }
        callout_reset(&sc->sc_watchdog, 60 * hz, wd33c93_watchdog, sc);
}


#ifdef DEBUG
void
wd33c93_hexdump(u_char *buf, int len)
{
        printf("{%d}:", len);
        while (len--)
                printf(" %02x", *buf++);
        printf("\n");
}


void
wd33c93_print_csr(u_char csr)
{
        switch (SCSI_PHASE(csr)) {
        case CMD_PHASE:
                printf("CMD_PHASE\n");
                break;

        case STATUS_PHASE:
                printf("STATUS_PHASE\n");
                break;

        case DATA_IN_PHASE:
                printf("DATAIN_PHASE\n");
                break;

        case DATA_OUT_PHASE:
                printf("DATAOUT_PHASE\n");
                break;

        case MESG_IN_PHASE:
                printf("MESG_IN_PHASE\n");
                break;

        case MESG_OUT_PHASE:
                printf("MESG_OUT_PHASE\n");
                break;

        default:
                switch (csr) {
                case SBIC_CSR_DISC_1:
                        printf("DISC_1\n");
                        break;

                case SBIC_CSR_RSLT_NI:
                        printf("RESELECT_NO_IFY\n");
                        break;

                case SBIC_CSR_RSLT_IFY:
                        printf("RESELECT_IFY\n");
                        break;

                case SBIC_CSR_SLT:
                        printf("SELECT\n");
                        break;

                case SBIC_CSR_SLT_ATN:
                        printf("SELECT, ATN\n");
                        break;

                case SBIC_CSR_UNK_GROUP:
                        printf("UNK_GROUP\n");
                        break;

                default:
                        printf("UNKNOWN csr=%02x\n", csr);
                }
        }
}
#endif