/*      $NetBSD: siop.c,v 1.71 2022/04/07 19:33:37 andvar 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.
 *
 *      @(#)siop.c      7.5 (Berkeley) 5/4/91
 */

/*
 * Copyright (c) 1994 Michael L. Hitch
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR 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.
 *
 *      @(#)siop.c      7.5 (Berkeley) 5/4/91
 */

/*
 * AMIGA 53C710 scsi adaptor driver
 */

#include "opt_ddb.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: siop.c,v 1.71 2022/04/07 19:33:37 andvar Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/disklabel.h>
#include <sys/buf.h>
#include <sys/malloc.h>

#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsiconf.h>
#include <machine/cpu.h>
#ifdef __m68k__
#include <m68k/cacheops.h>
#else
#define DCIAS(pa)
#endif
#include <amiga/amiga/custom.h>
#include <amiga/amiga/isr.h>
#include <amiga/dev/siopreg.h>
#include <amiga/dev/siopvar.h>

/*
 * SCSI delays
 * In u-seconds, primarily for state changes on the SPC.
 */
#define SCSI_CMD_WAIT   500000  /* wait per step of 'immediate' cmds */
#define SCSI_DATA_WAIT  500000  /* wait per data in/out step */
#define SCSI_INIT_WAIT  500000  /* wait per step (both) during init */

void siop_select(struct siop_softc *);
void siopabort(struct siop_softc *, siop_regmap_p, const char *);
void sioperror(struct siop_softc *, siop_regmap_p, u_char);
void siopstart(struct siop_softc *);
int  siop_checkintr(struct siop_softc *, u_char, u_char, u_char, int *);
void siopreset(struct siop_softc *);
void siopsetdelay(int);
void siop_scsidone(struct siop_acb *, int);
void siop_timeout(void *);
void siop_sched(struct siop_softc *);
void siop_poll(struct siop_softc *, struct siop_acb *);
void siopintr(struct siop_softc *);
void scsi_period_to_siop(struct siop_softc *, int);
void siop_start(struct siop_softc *, int, int, u_char *, int, u_char *, int);
void siop_dump_acb(struct siop_acb *);

/* 53C710 script */
const
#include <amiga/dev/siop_script.out>

/* default to not inhibit sync negotiation on any drive */
u_char siop_inhibit_sync[8] = { 0, 0, 0, 0, 0, 0, 0 }; /* initialize, so patchable */
u_char siop_allow_disc[8] = {3, 3, 3, 3, 3, 3, 3, 3};
int siop_no_dma = 0;

int siop_reset_delay = 250;     /* delay after reset, in milleseconds */

int siop_cmd_wait = SCSI_CMD_WAIT;
int siop_data_wait = SCSI_DATA_WAIT;
int siop_init_wait = SCSI_INIT_WAIT;

#ifdef DEBUG_SYNC
/*
 * sync period transfer lookup - only valid for 66 MHz clock
 */
static struct {
        unsigned char p;        /* period from sync request message */
        unsigned char r;        /* siop_period << 4 | sbcl */
} sync_tab[] = {
        { 60/4, 0<<4 | 1},
        { 76/4, 1<<4 | 1},
        { 92/4, 2<<4 | 1},
        { 92/4, 0<<4 | 2},
        {108/4, 3<<4 | 1},
        {116/4, 1<<4 | 2},
        {120/4, 4<<4 | 1},
        {120/4, 0<<4 | 3},
        {136/4, 5<<4 | 1},
        {140/4, 2<<4 | 2},
        {152/4, 6<<4 | 1},
        {152/4, 1<<4 | 3},
        {164/4, 3<<4 | 2},
        {168/4, 7<<4 | 1},
        {180/4, 2<<4 | 3},
        {184/4, 4<<4 | 2},
        {208/4, 5<<4 | 2},
        {212/4, 3<<4 | 3},
        {232/4, 6<<4 | 2},
        {240/4, 4<<4 | 3},
        {256/4, 7<<4 | 2},
        {272/4, 5<<4 | 3},
        {300/4, 6<<4 | 3},
        {332/4, 7<<4 | 3}
};
#endif

#ifdef DEBUG
/*
 *      0x01 - full debug
 *      0x02 - DMA chaining
 *      0x04 - siopintr
 *      0x08 - phase mismatch
 *      0x10 - <not used>
 *      0x20 - panic on unhandled exceptions
 *      0x100 - disconnect/reselect
 */
int     siop_debug = 0;
int     siopsync_debug = 0;
int     siopdma_hits = 0;
int     siopdma_misses = 0;
int     siopchain_ints = 0;
int     siopstarts = 0;
int     siopints = 0;
int     siopphmm = 0;
#define SIOP_TRACE_SIZE 128
#define SIOP_TRACE(a,b,c,d) \
        siop_trbuf[siop_trix] = (a); \
        siop_trbuf[siop_trix+1] = (b); \
        siop_trbuf[siop_trix+2] = (c); \
        siop_trbuf[siop_trix+3] = (d); \
        siop_trix = (siop_trix + 4) & (SIOP_TRACE_SIZE - 1);
u_char  siop_trbuf[SIOP_TRACE_SIZE];
int     siop_trix;
void siop_dump(struct siop_softc *);
void siop_dump_trace(void);
#else
#define SIOP_TRACE(a,b,c,d)
#endif


/*
 * default minphys routine for siop based controllers
 */
void
siop_minphys(struct buf *bp)
{

        /*
         * No max transfer at this level.
         */
        minphys(bp);
}

/*
 * used by specific siop controller
 *
 */
void
siop_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
                    void *arg)
{
        struct scsipi_xfer *xs;
#ifdef DIAGNOSTIC
        struct scsipi_periph *periph;
#endif
        struct siop_acb *acb;
        struct siop_softc *sc = device_private(chan->chan_adapter->adapt_dev);
        int flags, s;

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

                /* XXXX ?? */
                if (flags & XS_CTL_DATA_UIO)
                        panic("siop: scsi data uio requested");

                /* XXXX ?? */
                if (sc->sc_nexus && flags & XS_CTL_POLL)
/*                      panic("siop_scsicmd: busy");*/
                        printf("siop_scsicmd: busy\n");

                s = splbio();
                acb = sc->free_list.tqh_first;
                if (acb) {
                        TAILQ_REMOVE(&sc->free_list, acb, chain);
                }
                splx(s);

#ifdef DIAGNOSTIC
                /*
                 * This should never happen as we track the resources
                 * in the mid-layer.
                 */
                if (acb == NULL) {
                        scsipi_printaddr(periph);
                        printf("unable to allocate acb\n");
                        panic("siop_scsipi_request");
                }
#endif

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

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

                if (sc->sc_nexus == NULL)
                        siop_sched(sc);

                splx(s);

                if (flags & XS_CTL_POLL || siop_no_dma)
                        siop_poll(sc, acb);
                return;

        case ADAPTER_REQ_GROW_RESOURCES:
                return;

        case ADAPTER_REQ_SET_XFER_MODE:
                return;
        }
}

void
siop_poll(struct siop_softc *sc, struct siop_acb *acb)
{
        siop_regmap_p rp = sc->sc_siopp;
        struct scsipi_xfer *xs = acb->xs;
        int i;
        int status;
        u_char istat;
        u_char dstat;
        u_char sstat0;
        int s;
        int to;

        s = splbio();
        to = xs->timeout / 1000;
        if (sc->nexus_list.tqh_first)
                printf("%s: siop_poll called with disconnected device\n",
                    device_xname(sc->sc_dev));
        for (;;) {
                /* use cmd_wait values? */
                i = 50000;
                /* XXX spl0(); */
                while (((istat = rp->siop_istat) &
                    (SIOP_ISTAT_SIP | SIOP_ISTAT_DIP)) == 0) {
                        if (--i <= 0) {
#ifdef DEBUG
                                printf ("waiting: tgt %d cmd %02x sbcl %02x dsp %lx (+%lx) dcmd %lx ds %p timeout %d\n",
                                    xs->xs_periph->periph_target, acb->cmd.opcode,
                                    rp->siop_sbcl, rp->siop_dsp,
                                    rp->siop_dsp - sc->sc_scriptspa,
                                    *((volatile long *)&rp->siop_dcmd), &acb->ds, acb->xs->timeout);
#endif
                                i = 50000;
                                --to;
                                if (to <= 0) {
                                        siopreset(sc);
                                        return;
                                }
                        }
                        delay(20);
                }
                sstat0 = rp->siop_sstat0;
                dstat = rp->siop_dstat;
                if (siop_checkintr(sc, istat, dstat, sstat0, &status)) {
                        if (acb != sc->sc_nexus)
                                printf("%s: siop_poll disconnected device completed\n",
                                    device_xname(sc->sc_dev));
                        else if ((sc->sc_flags & SIOP_INTDEFER) == 0) {
                                sc->sc_flags &= ~SIOP_INTSOFF;
                                rp->siop_sien = sc->sc_sien;
                                rp->siop_dien = sc->sc_dien;
                        }
                        siop_scsidone(sc->sc_nexus, status);
                }

                if (xs->xs_status & XS_STS_DONE)
                        break;
        }
        splx(s);
}

/*
 * start next command that's ready
 */
void
siop_sched(struct siop_softc *sc)
{
        struct scsipi_periph *periph;
        struct siop_acb *acb;
        int i;

#ifdef DEBUG
        if (sc->sc_nexus) {
                printf("%s: siop_sched- nexus %p/%d ready %p/%d\n",
                    device_xname(sc->sc_dev), sc->sc_nexus,
                    sc->sc_nexus->xs->xs_periph->periph_target,
                    sc->ready_list.tqh_first,
                    sc->ready_list.tqh_first->xs->xs_periph->periph_target);
                return;
        }
#endif
        for (acb = sc->ready_list.tqh_first; acb; acb = acb->chain.tqe_next) {
                periph = acb->xs->xs_periph;
                i = periph->periph_target;
                if(!(sc->sc_tinfo[i].lubusy & (1 << periph->periph_lun))) {
                        struct siop_tinfo *ti = &sc->sc_tinfo[i];

                        TAILQ_REMOVE(&sc->ready_list, acb, chain);
                        sc->sc_nexus = acb;
                        periph = acb->xs->xs_periph;
                        ti = &sc->sc_tinfo[periph->periph_target];
                        ti->lubusy |= (1 << periph->periph_lun);
                        break;
                }
        }

        if (acb == NULL) {
#ifdef DEBUGXXX
                printf("%s: siop_sched didn't find ready command\n",
                    device_xname(sc->sc_dev));
#endif
                return;
        }

        if (acb->xs->xs_control & XS_CTL_RESET)
                siopreset(sc);

#if 0
        acb->cmd.bytes[0] |= slp->scsipi_scsi.lun << 5; /* XXXX */
#endif
        ++sc->sc_active;
        siop_select(sc);
}

void
siop_scsidone(struct siop_acb *acb, int stat)
{
        struct scsipi_xfer *xs;
        struct scsipi_periph *periph;
        struct siop_softc *sc;
        int dosched = 0;

        if (acb == NULL || (xs = acb->xs) == NULL) {
#ifdef DIAGNOSTIC
                printf("siop_scsidone: NULL acb or scsipi_xfer\n");
#if defined(DEBUG) && defined(DDB)
                Debugger();
#endif
#endif
                return;
        }

        callout_stop(&xs->xs_callout);

        periph = xs->xs_periph;
        sc = device_private(periph->periph_channel->chan_adapter->adapt_dev);

        xs->status = stat;
        xs->resid = 0;          /* XXXX */

        if (xs->error == XS_NOERROR) {
                if (stat == SCSI_CHECK || stat == SCSI_BUSY)
                        xs->error = XS_BUSY;
        }

        /*
         * Remove the ACB from whatever queue it's on.  We have to do a bit of
         * a hack to figure out which queue it's on.  Note that it is *not*
         * necessary to cdr down the ready queue, but we must cdr down the
         * nexus queue and see if it's there, so we can mark the unit as no
         * longer busy.  This code is sickening, but it works.
         */
        if (acb == sc->sc_nexus) {
                sc->sc_nexus = NULL;
                sc->sc_tinfo[periph->periph_target].lubusy &=
                        ~(1<<periph->periph_lun);
                if (sc->ready_list.tqh_first)
                        dosched = 1;    /* start next command */
                --sc->sc_active;
                SIOP_TRACE('d','a',stat,0)
        } else if (sc->ready_list.tqh_last == &acb->chain.tqe_next) {
                TAILQ_REMOVE(&sc->ready_list, acb, chain);
                SIOP_TRACE('d','r',stat,0)
        } else {
                register struct siop_acb *acb2;
                for (acb2 = sc->nexus_list.tqh_first; acb2;
                    acb2 = acb2->chain.tqe_next)
                        if (acb2 == acb) {
                                TAILQ_REMOVE(&sc->nexus_list, acb, chain);
                                sc->sc_tinfo[periph->periph_target].lubusy
                                        &= ~(1<<periph->periph_lun);
                                --sc->sc_active;
                                break;
                        }
                if (acb2)
                        ;
                else if (acb->chain.tqe_next) {
                        TAILQ_REMOVE(&sc->ready_list, acb, chain);
                        --sc->sc_active;
                } else {
                        printf("%s: can't find matching acb\n",
                            device_xname(sc->sc_dev));
#ifdef DDB
/*                      Debugger(); */
#endif
                }
                SIOP_TRACE('d','n',stat,0);
        }
        /* Put it on the free list. */
        acb->flags = ACB_FREE;
        TAILQ_INSERT_HEAD(&sc->free_list, acb, chain);

        sc->sc_tinfo[periph->periph_target].cmds++;

        scsipi_done(xs);

        if (dosched && sc->sc_nexus == NULL)
                siop_sched(sc);
}

void
siopabort(register struct siop_softc *sc, siop_regmap_p rp, const char *where)
{
#ifdef fix_this
        int i;
#endif

        printf ("%s: abort %s: dstat %02x, sstat0 %02x sbcl %02x\n",
            device_xname(sc->sc_dev),
            where, rp->siop_dstat, rp->siop_sstat0, rp->siop_sbcl);

        if (sc->sc_active > 0) {
#ifdef TODO
      SET_SBIC_cmd (rp, SBIC_CMD_ABORT);
      WAIT_CIP (rp);

      GET_SBIC_asr (rp, asr);
      if (asr & (SBIC_ASR_BSY|SBIC_ASR_LCI))
        {
          /* ok, get more drastic.. */

          SET_SBIC_cmd (rp, SBIC_CMD_RESET);
          delay(25);
          SBIC_WAIT(rp, SBIC_ASR_INT, 0);
          GET_SBIC_csr (rp, csr);       /* clears interrupt also */

          return;
        }

      do
        {
          SBIC_WAIT (rp, SBIC_ASR_INT, 0);
          GET_SBIC_csr (rp, csr);
        }
      while ((csr != SBIC_CSR_DISC) && (csr != SBIC_CSR_DISC_1)
              && (csr != SBIC_CSR_CMD_INVALID));
#endif

                /* lets just hope it worked.. */
#ifdef fix_this
                for (i = 0; i < 2; ++i) {
                        if (sc->sc_iob[i].sc_xs && &sc->sc_iob[i] !=
                            sc->sc_cur) {
                                printf ("siopabort: cleanup!\n");
                                sc->sc_iob[i].sc_xs = NULL;
                        }
                }
#endif  /* fix_this */
/*              sc->sc_active = 0; */
        }
}

void
siopinitialize(struct siop_softc *sc)
{
        int i;
        u_int inhibit_sync;
        extern u_long scsi_nosync;
        extern int shift_nosync;

        /*
         * Need to check that scripts is on a long word boundary
         * Also should verify that dev doesn't span non-contiguous
         * physical pages.
         */
        sc->sc_scriptspa = kvtop((void *)__UNCONST(scripts));

        /*
         * malloc sc_acb to ensure that DS is on a long word boundary.
         */

        sc->sc_acb = malloc(sizeof(struct siop_acb) * SIOP_NACB,
                M_DEVBUF, M_WAITOK);

        sc->sc_tcp[1] = 1000 / sc->sc_clock_freq;
        sc->sc_tcp[2] = 1500 / sc->sc_clock_freq;
        sc->sc_tcp[3] = 2000 / sc->sc_clock_freq;
        sc->sc_minsync = sc->sc_tcp[1];         /* in 4ns units */
        if (sc->sc_minsync < 25)
                sc->sc_minsync = 25;
        if (sc->sc_clock_freq <= 25) {
                sc->sc_dcntl |= 0x80;           /* SCLK/1 */
                sc->sc_tcp[0] = sc->sc_tcp[1];
        } else if (sc->sc_clock_freq <= 37) {
                sc->sc_dcntl |= 0x40;           /* SCLK/1.5 */
                sc->sc_tcp[0] = sc->sc_tcp[2];
        } else if (sc->sc_clock_freq <= 50) {
                sc->sc_dcntl |= 0x00;           /* SCLK/2 */
                sc->sc_tcp[0] = sc->sc_tcp[3];
        } else {
                sc->sc_dcntl |= 0xc0;           /* SCLK/3 */
                sc->sc_tcp[0] = 3000 / sc->sc_clock_freq;
        }

        if (scsi_nosync) {
                inhibit_sync = (scsi_nosync >> shift_nosync) & 0xff;
                shift_nosync += 8;
#ifdef DEBUG
                if (inhibit_sync)
                        printf("%s: Inhibiting synchronous transfer %02x\n",
                                device_xname(sc->sc_dev), inhibit_sync);
#endif
                for (i = 0; i < 8; ++i)
                        if (inhibit_sync & (1 << i))
                                siop_inhibit_sync[i] = 1;
        }

        siopreset (sc);
}

void
siop_timeout(void *arg)
{
        struct siop_acb *acb;
        struct scsipi_periph *periph;
        struct siop_softc *sc;
        int s;

        acb = arg;
        periph = acb->xs->xs_periph;
        sc = device_private(periph->periph_channel->chan_adapter->adapt_dev);
        scsipi_printaddr(periph);
        printf("timed out\n");

        s = splbio();

        acb->xs->error = XS_TIMEOUT;
        siopreset(sc);

        splx(s);
}

void
siopreset(struct siop_softc *sc)
{
        siop_regmap_p rp;
        u_int i, s;
        u_char  dummy;
        struct siop_acb *acb;

        rp = sc->sc_siopp;

        if (sc->sc_flags & SIOP_ALIVE)
                siopabort(sc, rp, "reset");

        printf("%s: ", device_xname(sc->sc_dev));               /* XXXX */

        s = splbio();

        /*
         * Reset the chip
         * XXX - is this really needed?
         */
        rp->siop_istat |= SIOP_ISTAT_ABRT;      /* abort current script */
        rp->siop_istat |= SIOP_ISTAT_RST;               /* reset chip */
        rp->siop_istat &= ~SIOP_ISTAT_RST;
        /*
         * Reset SCSI bus (do we really want this?)
         */
        rp->siop_sien = 0;
        rp->siop_scntl1 |= SIOP_SCNTL1_RST;
        delay(1);
        rp->siop_scntl1 &= ~SIOP_SCNTL1_RST;

        /*
         * Set up various chip parameters
         */
        rp->siop_scntl0 = SIOP_ARB_FULL | SIOP_SCNTL0_EPC | SIOP_SCNTL0_EPG;
        rp->siop_scntl1 = SIOP_SCNTL1_ESR;
        rp->siop_dcntl = sc->sc_dcntl;
        rp->siop_dmode = 0x80;  /* burst length = 4 */
        rp->siop_sien = 0x00;   /* don't enable interrupts yet */
        rp->siop_dien = 0x00;   /* don't enable interrupts yet */
        rp->siop_scid = 1 << sc->sc_channel.chan_id;
        rp->siop_dwt = 0x00;
        rp->siop_ctest0 |= SIOP_CTEST0_BTD | SIOP_CTEST0_EAN;
        rp->siop_ctest7 |= sc->sc_ctest7;

        /* will need to re-negotiate sync xfers */
        memset(&sc->sc_sync, 0, sizeof (sc->sc_sync));

        i = rp->siop_istat;
        if (i & SIOP_ISTAT_SIP)
                dummy = rp->siop_sstat0;
        if (i & SIOP_ISTAT_DIP)
                dummy = rp->siop_dstat;

        __USE(dummy);
        splx (s);

        delay (siop_reset_delay * 1000);
        printf("siop id %d reset V%d\n", sc->sc_channel.chan_id,
            rp->siop_ctest8 >> 4);

        if ((sc->sc_flags & SIOP_ALIVE) == 0) {
                TAILQ_INIT(&sc->ready_list);
                TAILQ_INIT(&sc->nexus_list);
                TAILQ_INIT(&sc->free_list);
                sc->sc_nexus = NULL;
                acb = sc->sc_acb;
                memset(acb, 0, sizeof(struct siop_acb) * SIOP_NACB);
                for (i = 0; i < SIOP_NACB; i++) {
                        TAILQ_INSERT_TAIL(&sc->free_list, acb, chain);
                        acb++;
                }
                memset(sc->sc_tinfo, 0, sizeof(sc->sc_tinfo));
        } else {
                if (sc->sc_nexus != NULL) {
                        sc->sc_nexus->xs->error = XS_RESET;
                        siop_scsidone(sc->sc_nexus, sc->sc_nexus->stat[0]);
                }
                while ((acb = sc->nexus_list.tqh_first) > 0) {
                        acb->xs->error = XS_RESET;
                        siop_scsidone(acb, acb->stat[0]);
                }
        }

        sc->sc_flags |= SIOP_ALIVE;
        sc->sc_flags &= ~(SIOP_INTDEFER|SIOP_INTSOFF);
        /* enable SCSI and DMA interrupts */
        sc->sc_sien = SIOP_SIEN_M_A | SIOP_SIEN_STO | /*SIOP_SIEN_SEL |*/ SIOP_SIEN_SGE |
            SIOP_SIEN_UDC | SIOP_SIEN_RST | SIOP_SIEN_PAR;
        sc->sc_dien = SIOP_DIEN_BF | SIOP_DIEN_ABRT | SIOP_DIEN_SIR |
            /*SIOP_DIEN_WTD |*/ SIOP_DIEN_IID;
        rp->siop_sien = sc->sc_sien;
        rp->siop_dien = sc->sc_dien;
}

/*
 * Setup Data Storage for 53C710 and start SCRIPTS processing
 */

void
siop_start(struct siop_softc *sc, int target, int lun, u_char *cbuf, int clen,
           u_char *buf, int len)
{
        siop_regmap_p rp = sc->sc_siopp;
        int nchain;
        int count, tcount;
        char *addr, *dmaend;
        struct siop_acb *acb = sc->sc_nexus;
#ifdef DEBUG
        int i;
#endif

#ifdef DEBUG
        if (siop_debug & 0x100 && rp->siop_sbcl & SIOP_BSY) {
                printf ("ACK! siop was busy: rp %p script %p dsa %p active %ld\n",
                    rp, &scripts, &acb->ds, sc->sc_active);
                printf ("istat %02x sfbr %02x lcrc %02x sien %02x dien %02x\n",
                    rp->siop_istat, rp->siop_sfbr, rp->siop_lcrc,
                    rp->siop_sien, rp->siop_dien);
#ifdef DDB
                /*Debugger();*/
#endif
        }
#endif
        acb->msgout[0] = MSG_IDENTIFY | lun;
        if (siop_allow_disc[target] & 2 ||
            (siop_allow_disc[target] && len == 0))
                acb->msgout[0] = MSG_IDENTIFY_DR | lun;
        acb->status = 0;
        acb->stat[0] = -1;
        acb->msg[0] = -1;
        acb->ds.scsi_addr = (0x10000 << target) | (sc->sc_sync[target].sxfer << 8);
        acb->ds.idlen = 1;
        acb->ds.idbuf = (char *) kvtop(&acb->msgout[0]);
        acb->ds.cmdlen = clen;
        acb->ds.cmdbuf = (char *) kvtop(cbuf);
        acb->ds.stslen = 1;
        acb->ds.stsbuf = (char *) kvtop(&acb->stat[0]);
        acb->ds.msglen = 1;
        acb->ds.msgbuf = (char *) kvtop(&acb->msg[0]);
        acb->msg[1] = -1;
        acb->ds.msginlen = 1;
        acb->ds.extmsglen = 1;
        acb->ds.synmsglen = 3;
        acb->ds.msginbuf = (char *) kvtop(&acb->msg[1]);
        acb->ds.extmsgbuf = (char *) kvtop(&acb->msg[2]);
        acb->ds.synmsgbuf = (char *) kvtop(&acb->msg[3]);
        memset(&acb->ds.chain, 0, sizeof (acb->ds.chain));

        /*
         * Negotiate wide is the initial negotiation state;  since the 53c710
         * doesn't do wide transfers, just begin the synchronous transfer
         * negotiation here.
         */
        if (sc->sc_sync[target].state == NEG_WIDE) {
                if (siop_inhibit_sync[target]) {
                        sc->sc_sync[target].state = NEG_DONE;
                        sc->sc_sync[target].sbcl = 0;
                        sc->sc_sync[target].sxfer = 0;
#ifdef DEBUG
                        if (siopsync_debug)
                                printf ("Forcing target %d asynchronous\n", target);
#endif
                }
                else {
                        acb->msg[2] = -1;
                        acb->msgout[1] = MSG_EXT_MESSAGE;
                        acb->msgout[2] = 3;
                        acb->msgout[3] = MSG_SYNC_REQ;
#ifdef MAXTOR_SYNC_KLUDGE
                        acb->msgout[4] = 50 / 4;        /* ask for ridiculous period */
#else
                        acb->msgout[4] = sc->sc_minsync;
#endif
                        acb->msgout[5] = SIOP_MAX_OFFSET;
                        acb->ds.idlen = 6;
                        sc->sc_sync[target].state = NEG_WAITS;
#ifdef DEBUG
                        if (siopsync_debug)
                                printf ("Sending sync request to target %d\n", target);
#endif
                }
        }

/*
 * Build physical DMA addresses for scatter/gather I/O
 */
        acb->iob_buf = buf;
        acb->iob_len = len;
        acb->iob_curbuf = acb->iob_curlen = 0;
        nchain = 0;
        count = len;
        addr = buf;
        dmaend = NULL;
        while (count > 0) {
                acb->ds.chain[nchain].databuf = (char *) kvtop (addr);
                if (count < (tcount = PAGE_SIZE - ((int) addr & PGOFSET)))
                        tcount = count;
                acb->ds.chain[nchain].datalen = tcount;
                addr += tcount;
                count -= tcount;
                if (acb->ds.chain[nchain].databuf == dmaend) {
                        dmaend += acb->ds.chain[nchain].datalen;
                        acb->ds.chain[nchain].datalen = 0;
                        acb->ds.chain[--nchain].datalen += tcount;
#ifdef DEBUG
                        ++siopdma_hits;
#endif
                }
                else {
                        dmaend = acb->ds.chain[nchain].databuf +
                            acb->ds.chain[nchain].datalen;
                        acb->ds.chain[nchain].datalen = tcount;
#ifdef DEBUG
                        if (nchain)     /* Don't count miss on first one */
                                ++siopdma_misses;
#endif
                }
                ++nchain;
        }
#ifdef DEBUG
        if (nchain != 1 && len != 0 && siop_debug & 3) {
                printf ("DMA chaining set: %d\n", nchain);
                for (i = 0; i < nchain; ++i) {
                        printf ("  [%d] %8p %lx\n", i, acb->ds.chain[i].databuf,
                            acb->ds.chain[i].datalen);
                }
        }
#endif

        /* push data cache for all data the 53c710 needs to access */
        dma_cachectl ((void *)acb, sizeof (struct siop_acb));
        dma_cachectl (cbuf, clen);
        if (buf != NULL && len != 0)
                dma_cachectl (buf, len);
#ifdef DEBUG
        if (siop_debug & 0x100 && rp->siop_sbcl & SIOP_BSY) {
                printf ("ACK! siop was busy at start: rp %p script %p dsa %p active %ld\n",
                    rp, &scripts, &acb->ds, sc->sc_active);
#ifdef DDB
                /*Debugger();*/
#endif
        }
#endif
        if (sc->nexus_list.tqh_first == NULL) {
                callout_reset(&acb->xs->xs_callout,
                    mstohz(acb->xs->timeout) + 1, siop_timeout, acb);
                if (rp->siop_istat & SIOP_ISTAT_CON)
                        printf("%s: siop_select while connected?\n",
                            device_xname(sc->sc_dev));
                rp->siop_temp = 0;
                rp->siop_sbcl = sc->sc_sync[target].sbcl;
                rp->siop_dsa = kvtop((void *)&acb->ds);
                rp->siop_dsp = sc->sc_scriptspa;
                SIOP_TRACE('s',1,0,0)
        } else {
                if ((rp->siop_istat & SIOP_ISTAT_CON) == 0) {
                        rp->siop_istat = SIOP_ISTAT_SIGP;
                        SIOP_TRACE('s',2,0,0);
                }
                else {
                        SIOP_TRACE('s',3,rp->siop_istat,0);
                }
        }
#ifdef DEBUG
        ++siopstarts;
#endif
}

/*
 * Process a DMA or SCSI interrupt from the 53C710 SIOP
 */

int
siop_checkintr(struct siop_softc *sc, u_char istat, u_char dstat,
               u_char sstat0, int *status)
{
        siop_regmap_p rp = sc->sc_siopp;
        struct siop_acb *acb = sc->sc_nexus;
        int     target = 0;
        int     dfifo, dbc, sstat1;

        dfifo = rp->siop_dfifo;
        dbc = rp->siop_dbc0;
        sstat1 = rp->siop_sstat1;
        rp->siop_ctest8 |= SIOP_CTEST8_CLF;
        while ((rp->siop_ctest1 & SIOP_CTEST1_FMT) != SIOP_CTEST1_FMT)
                ;
        rp->siop_ctest8 &= ~SIOP_CTEST8_CLF;
#ifdef DEBUG
        ++siopints;
#if 0
        if (siop_debug & 0x100) {
                DCIAS(&acb->stat[0]);   /* XXX */
                printf ("siopchkintr: istat %x dstat %x sstat0 %x dsps %x sbcl %x sts %x msg %x\n",
                    istat, dstat, sstat0, rp->siop_dsps, rp->siop_sbcl, acb->stat[0], acb->msg[0]);
                printf ("sync msg in: %02x %02x %02x %02x %02x %02x\n",
                    acb->msg[0], acb->msg[1], acb->msg[2],
                    acb->msg[3], acb->msg[4], acb->msg[5]);
        }
#endif
        if (rp->siop_dsp && (rp->siop_dsp < sc->sc_scriptspa ||
            rp->siop_dsp >= sc->sc_scriptspa + sizeof(scripts))) {
                printf ("%s: dsp not within script dsp %lx scripts %lx:%lx",
                    device_xname(sc->sc_dev), rp->siop_dsp, sc->sc_scriptspa,
                    sc->sc_scriptspa + sizeof(scripts));
                printf(" istat %x dstat %x sstat0 %x\n",
                    istat, dstat, sstat0);
#ifdef DDB
                Debugger();
#endif
        }
#endif
        SIOP_TRACE('i',dstat,istat,(istat&SIOP_ISTAT_DIP)?rp->siop_dsps&0xff:sstat0);
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff00) {
                /* Normal completion status, or check condition */
#ifdef DEBUG
                if (rp->siop_dsa != kvtop((void *)&acb->ds)) {
                        printf ("siop: invalid dsa: %lx %x\n", rp->siop_dsa,
                            (unsigned)kvtop((void *)&acb->ds));
                        panic("*** siop DSA invalid ***");
                }
#endif
                target = acb->xs->xs_periph->periph_target;
                if (sc->sc_sync[target].state == NEG_WAITS) {
                        if (acb->msg[1] == 0xff)
                                printf ("%s: target %d ignored sync request\n",
                                    device_xname(sc->sc_dev), target);
                        else if (acb->msg[1] == MSG_REJECT)
                                printf ("%s: target %d rejected sync request\n",
                                    device_xname(sc->sc_dev), target);
                        else
/* XXX - need to set sync transfer parameters */
                                printf("%s: target %d (sync) %02x %02x %02x\n",
                                    device_xname(sc->sc_dev), target, acb->msg[1],
                                    acb->msg[2], acb->msg[3]);
                        sc->sc_sync[target].state = NEG_DONE;
                }
                dma_cachectl(&acb->stat[0], 1);
                *status = acb->stat[0];
#ifdef DEBUG
                if (rp->siop_sbcl & SIOP_BSY) {
                        /*printf ("ACK! siop was busy at end: rp %x script %x dsa %x\n",
                            rp, &scripts, &acb->ds);*/
#ifdef DDB
                        /*Debugger();*/
#endif
                }
                if (acb->msg[0] != 0x00)
                        printf("%s: message was not COMMAND COMPLETE: %x\n",
                            device_xname(sc->sc_dev), acb->msg[0]);
#endif
                if (sc->nexus_list.tqh_first)
                        rp->siop_dcntl |= SIOP_DCNTL_STD;
                return 1;
        }
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff0b) {
                target = acb->xs->xs_periph->periph_target;
                if (acb->msg[1] == MSG_EXT_MESSAGE && acb->msg[2] == 3 &&
                    acb->msg[3] == MSG_SYNC_REQ) {
#ifdef DEBUG
                        if (siopsync_debug)
                                printf ("sync msg in: %02x %02x %02x %02x %02x %02x\n",
                                    acb->msg[0], acb->msg[1], acb->msg[2],
                                    acb->msg[3], acb->msg[4], acb->msg[5]);
#endif
                        sc->sc_sync[target].sxfer = 0;
                        sc->sc_sync[target].sbcl = 0;
                        if (acb->msg[2] == 3 &&
                            acb->msg[3] == MSG_SYNC_REQ &&
                            acb->msg[5] != 0) {
#ifdef MAXTOR_KLUDGE
                                /*
                                 * Kludge for my Maxtor XT8580S
                                 * It accepts whatever we request, even
                                 * though it won't work.  So we ask for
                                 * a short period than we can handle.  If
                                 * the device says it can do it, use 208ns.
                                 * If the device says it can do less than
                                 * 100ns, then we limit it to 100ns.
                                 */
                                if (acb->msg[4] && acb->msg[4] < 100 / 4) {
#ifdef DEBUG
                                        printf ("%d: target %d wanted %dns period\n",
                                            device_xname(sc->sc_dev), target,
                                            acb->msg[4] * 4);
#endif
                                        if (acb->msg[4] == 50 / 4)
                                                acb->msg[4] = 208 / 4;
                                        else
                                                acb->msg[4] = 100 / 4;
                                }
#endif /* MAXTOR_KLUDGE */
                                printf ("%s: target %d now synchronous, period=%dns, offset=%d\n",
                                    device_xname(sc->sc_dev), target,
                                    acb->msg[4] * 4, acb->msg[5]);
                                scsi_period_to_siop (sc, target);
                        }
                        rp->siop_sxfer = sc->sc_sync[target].sxfer;
                        rp->siop_sbcl = sc->sc_sync[target].sbcl;
                        if (sc->sc_sync[target].state == NEG_WAITS) {
                                sc->sc_sync[target].state = NEG_DONE;
                                rp->siop_dsp = sc->sc_scriptspa + Ent_clear_ack;
                                return(0);
                        }
                        rp->siop_dcntl |= SIOP_DCNTL_STD;
                        sc->sc_sync[target].state = NEG_DONE;
                        return (0);
                }
                /* XXX - not SDTR message */
        }
        if (sstat0 & SIOP_SSTAT0_M_A) {         /* Phase mismatch */
#ifdef DEBUG
                ++siopphmm;
                if (acb == NULL)
                        printf("%s: Phase mismatch with no active command?\n",
                            device_xname(sc->sc_dev));
#endif
                if (acb->iob_len) {
                        int adjust;
                        adjust = ((dfifo - (dbc & 0x7f)) & 0x7f);
                        if (sstat1 & SIOP_SSTAT1_ORF)
                                ++adjust;
                        if (sstat1 & SIOP_SSTAT1_OLF)
                                ++adjust;
                        acb->iob_curlen = 
                            *((long *)__UNVOLATILE(&rp->siop_dcmd)) & 0xffffff;
                        acb->iob_curlen += adjust;
                        acb->iob_curbuf = 
                            *((long *)__UNVOLATILE(&rp->siop_dnad)) - adjust;
#ifdef DEBUG
                        if (siop_debug & 0x100) {
                                int i;
                                printf ("Phase mismatch: curbuf %lx curlen %lx dfifo %x dbc %x sstat1 %x adjust %x sbcl %x starts %d acb %p\n",
                                    acb->iob_curbuf, acb->iob_curlen, dfifo,
                                    dbc, sstat1, adjust, rp->siop_sbcl, 
                                    siopstarts, acb);
                                if (acb->ds.chain[1].datalen) {
                                        for (i = 0; acb->ds.chain[i].datalen; ++i)
                                                printf("chain[%d] addr %p len %lx\n",
                                                    i, acb->ds.chain[i].databuf,
                                                    acb->ds.chain[i].datalen);
                                }
                        }
#endif
                        dma_cachectl ((void *)acb, sizeof(*acb));
                }
#ifdef DEBUG
                SIOP_TRACE('m',rp->siop_sbcl,(rp->siop_dsp>>8),rp->siop_dsp);
                if (siop_debug & 9)
                        printf ("Phase mismatch: %x dsp +%lx dcmd %lx\n",
                            rp->siop_sbcl,
                            rp->siop_dsp - sc->sc_scriptspa,
                            *((volatile long *)&rp->siop_dcmd));
#endif
                if ((rp->siop_sbcl & SIOP_REQ) == 0) {
                        printf ("Phase mismatch: REQ not asserted! %02x dsp %lx\n",
                            rp->siop_sbcl, rp->siop_dsp);
#if defined(DEBUG) && defined(DDB)
                        /*Debugger(); XXX is*/
#endif
                }
                switch (rp->siop_sbcl & 7) {
                case 0:         /* data out */
                case 1:         /* data in */
                case 2:         /* status */
                case 3:         /* command */
                case 6:         /* message in */
                case 7:         /* message out */
                        rp->siop_dsp = sc->sc_scriptspa + Ent_switch;
                        break;
                default:
                        goto bad_phase;
                }
                return 0;
        }
        if (sstat0 & SIOP_SSTAT0_STO) {         /* Select timed out */
#ifdef DEBUG
                if (acb == NULL)
                        printf("%s: Select timeout with no active command?\n",
                            device_xname(sc->sc_dev));
                if (rp->siop_sbcl & SIOP_BSY) {
                        printf ("ACK! siop was busy at timeout: rp %p script %p dsa %p\n",
                            rp, &scripts, &acb->ds);
                        printf(" sbcl %x sdid %x istat %x dstat %x sstat0 %x\n",
                            rp->siop_sbcl, rp->siop_sdid, istat, dstat, sstat0);
                        if (!(rp->siop_sbcl & SIOP_BSY)) {
                                printf ("Yikes, it's not busy now!\n");
#if 0
                                *status = -1;
                                if (sc->nexus_list.tqh_first)
                                        rp->siop_dsp = sc->sc_scriptspa + Ent_wait_reselect;
                                return 1;
#endif
                        }
/*                      rp->siop_dcntl |= SIOP_DCNTL_STD;*/
                        return (0);
                }
#endif
                *status = -1;
                acb->xs->error = XS_SELTIMEOUT;
                if (sc->nexus_list.tqh_first)
                        rp->siop_dsp = sc->sc_scriptspa + Ent_wait_reselect;
                return 1;
        }
        if (acb)
                target = acb->xs->xs_periph->periph_target;
        else
                target = 7;
        if (sstat0 & SIOP_SSTAT0_UDC) {
#ifdef DEBUG
                if (acb == NULL)
                        printf("%s: Unexpected disconnect with no active command?\n",
                            device_xname(sc->sc_dev));
                printf ("%s: target %d disconnected unexpectedly\n",
                   device_xname(sc->sc_dev), target);
#endif
#if 0
                siopabort (sc, rp, "siopchkintr");
#endif
                *status = STS_BUSY;
                if (sc->nexus_list.tqh_first)
                        rp->siop_dsp = sc->sc_scriptspa + Ent_wait_reselect;
                return (acb != NULL);
        }
        if (dstat & SIOP_DSTAT_SIR && (rp->siop_dsps == 0xff01 ||
            rp->siop_dsps == 0xff02)) {
#ifdef DEBUG
                if (siop_debug & 0x100)
                        printf ("%s: ID %02x disconnected TEMP %lx (+%lx) curbuf %lx curlen %lx buf %p len %lx dfifo %x dbc %x sstat1 %x starts %d acb %p\n",
                            device_xname(sc->sc_dev), 1 << target, rp->siop_temp,
                            rp->siop_temp ? rp->siop_temp - sc->sc_scriptspa : 0,
                            acb->iob_curbuf, acb->iob_curlen,
                            acb->ds.chain[0].databuf, acb->ds.chain[0].datalen, dfifo, dbc, sstat1, siopstarts, acb);
#endif
                if (acb == NULL) {
                        printf("%s: Disconnect with no active command?\n",
                            device_xname(sc->sc_dev));
                        return (0);
                }
                /*
                 * XXXX need to update iob_curbuf/iob_curlen to reflect
                 * current data transferred.  If device disconnected in
                 * the middle of a DMA block, they should already be set
                 * by the phase change interrupt.  If the disconnect
                 * occurs on a DMA block boundary, we have to figure out
                 * which DMA block it was.
                 */
                if (acb->iob_len && rp->siop_temp) {
                        int n = rp->siop_temp - sc->sc_scriptspa;

                        if (acb->iob_curlen && acb->iob_curlen != acb->ds.chain[0].datalen)
                                printf("%s: iob_curbuf/len already set? n %x iob %lx/%lx chain[0] %p/%lx\n",
                                    device_xname(sc->sc_dev), n, acb->iob_curbuf, acb->iob_curlen,
                                    acb->ds.chain[0].databuf, acb->ds.chain[0].datalen);
                        if (n < Ent_datain)
                                n = (n - Ent_dataout) / 16;
                        else
                                n = (n - Ent_datain) / 16;
                        if (n <= 0 && n > DMAMAXIO)
                                printf("TEMP invalid %d\n", n);
                        else {
                                acb->iob_curbuf = (u_long)acb->ds.chain[n].databuf;
                                acb->iob_curlen = acb->ds.chain[n].datalen;
                        }
#ifdef DEBUG
                        if (siop_debug & 0x100) {
                                printf("%s: TEMP offset %d", device_xname(sc->sc_dev), n);
                                printf(" curbuf %lx curlen %lx\n", acb->iob_curbuf,
                                    acb->iob_curlen);
                        }
#endif
                }
                /*
                 * If data transfer was interrupted by disconnect, iob_curbuf
                 * and iob_curlen should reflect the point of interruption.
                 * Adjust the DMA chain so that the data transfer begins
                 * at the appropriate place upon reselection.
                 * XXX This should only be done on save data pointer message?
                 */
                if (acb->iob_curlen) {
                        int i, j;

#ifdef DEBUG
                        if (siop_debug & 0x100)
                                printf ("%s: adjusting DMA chain\n",
                                    device_xname(sc->sc_dev));
                        if (rp->siop_dsps == 0xff02)
                                printf ("%s: ID %02x disconnected without Save Data Pointers\n",
                                    device_xname(sc->sc_dev), 1 << target);
#endif
/* XXX is:              if (rp->siop_dsps != 0xff02) { */
                                /* not disconnected without save data ptr */
                        for (i = 0; i < DMAMAXIO; ++i) {
                                if (acb->ds.chain[i].datalen == 0)
                                        break;
                                if (acb->iob_curbuf >= (long)acb->ds.chain[i].databuf &&
                                    acb->iob_curbuf < (long)(acb->ds.chain[i].databuf +
                                    acb->ds.chain[i].datalen))
                                        break;
                        }
                        if (i >= DMAMAXIO || acb->ds.chain[i].datalen == 0) {
                                printf("couldn't find saved data pointer: ");
                                printf("curbuf %lx curlen %lx i %d\n",
                                    acb->iob_curbuf, acb->iob_curlen, i);
#ifdef DDB
                                Debugger();
#endif
                        }
/* XXX is:              }                       */
#ifdef DEBUG
                        if (siop_debug & 0x100)
                                printf("  chain[0]: %p/%lx -> %lx/%lx\n",
                                    acb->ds.chain[0].databuf,
                                    acb->ds.chain[0].datalen,
                                    acb->iob_curbuf,
                                    acb->iob_curlen);
#endif
                        acb->ds.chain[0].databuf = (char *)acb->iob_curbuf;
                        acb->ds.chain[0].datalen = acb->iob_curlen;
                        for (j = 1, ++i; i < DMAMAXIO && acb->ds.chain[i].datalen; ++i, ++j) {
#ifdef DEBUG
                        if (siop_debug & 0x100)
                                printf("  chain[%d]: %p/%lx -> %p/%lx\n", j,
                                    acb->ds.chain[j].databuf,
                                    acb->ds.chain[j].datalen,
                                    acb->ds.chain[i].databuf,
                                    acb->ds.chain[i].datalen);
#endif
                                acb->ds.chain[j].databuf = acb->ds.chain[i].databuf;
                                acb->ds.chain[j].datalen = acb->ds.chain[i].datalen;
                        }
                        if (j < DMAMAXIO)
                                acb->ds.chain[j].datalen = 0;
                        DCIAS(kvtop((void *)&acb->ds.chain));
                }
                ++sc->sc_tinfo[target].dconns;
                /*
                 * add nexus to waiting list
                 * clear nexus
                 * try to start another command for another target/lun
                 */
                acb->status = sc->sc_flags & SIOP_INTSOFF;
                TAILQ_INSERT_HEAD(&sc->nexus_list, acb, chain);
                sc->sc_nexus = NULL;            /* no current device */
                /* start script to wait for reselect */
                if (sc->sc_nexus == NULL)
                        rp->siop_dsp = sc->sc_scriptspa + Ent_wait_reselect;
/* XXXX start another command ? */
                if (sc->ready_list.tqh_first)
                        siop_sched(sc);
                return (0);
        }
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff03) {
                int reselid = rp->siop_scratch & 0x7f;
                int reselun = rp->siop_sfbr & 0x07;

                sc->sc_sstat1 = rp->siop_sbcl;  /* XXXX save current SBCL */
#ifdef DEBUG
                if (siop_debug & 0x100)
                        printf ("%s: target ID %02x reselected dsps %lx\n",
                             device_xname(sc->sc_dev), reselid,
                             rp->siop_dsps);
                if ((rp->siop_sfbr & 0x80) == 0)
                        printf("%s: Reselect message in was not identify: %x\n",
                            device_xname(sc->sc_dev), rp->siop_sfbr);
#endif
                if (sc->sc_nexus) {
#ifdef DEBUG
                        if (siop_debug & 0x100)
                                printf ("%s: reselect ID %02x w/active\n",
                                    device_xname(sc->sc_dev), reselid);
#endif
                        TAILQ_INSERT_HEAD(&sc->ready_list, sc->sc_nexus, chain);
                        sc->sc_tinfo[sc->sc_nexus->xs->xs_periph->periph_target].lubusy
                            &= ~(1 << sc->sc_nexus->xs->xs_periph->periph_lun);
                        --sc->sc_active;
                }
                /*
                 * locate acb of reselecting device
                 * set sc->sc_nexus to acb
                 */
                for (acb = sc->nexus_list.tqh_first; acb;
                    acb = acb->chain.tqe_next) {
                        if (reselid != (acb->ds.scsi_addr >> 16) ||
                            reselun != (acb->msgout[0] & 0x07))
                                continue;
                        TAILQ_REMOVE(&sc->nexus_list, acb, chain);
                        sc->sc_nexus = acb;
                        sc->sc_flags |= acb->status;
                        acb->status = 0;
                        DCIAS(kvtop(&acb->stat[0]));
                        rp->siop_dsa = kvtop((void *)&acb->ds);
                        rp->siop_sxfer =
                                sc->sc_sync[acb->xs->xs_periph->periph_target].sxfer;
                        rp->siop_sbcl =
                                sc->sc_sync[acb->xs->xs_periph->periph_target].sbcl;
                        break;
                }
                if (acb == NULL) {
                        printf("%s: target ID %02x reselect nexus_list %p\n",
                            device_xname(sc->sc_dev), reselid,
                            sc->nexus_list.tqh_first);
                        panic("unable to find reselecting device");
                }
                dma_cachectl ((void *)acb, sizeof(*acb));
                rp->siop_temp = 0;
                rp->siop_dcntl |= SIOP_DCNTL_STD;
                return (0);
        }
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff04) {
#ifdef DEBUG
                u_short ctest2 = rp->siop_ctest2;

                /* reselect was interrupted (by Sig_P or select) */
                if (siop_debug & 0x100 ||
                    (ctest2 & SIOP_CTEST2_SIGP) == 0)
                        printf ("%s: reselect interrupted (Sig_P?) scntl1 %x ctest2 %x sfbr %x istat %x/%x\n",
                            device_xname(sc->sc_dev), rp->siop_scntl1,
                            ctest2, rp->siop_sfbr, istat, rp->siop_istat);
#endif
                /* XXX assumes it was not select */
                if (sc->sc_nexus == NULL) {
#ifdef DEBUG
                        printf("%s: reselect interrupted, sc_nexus == NULL\n",
                            device_xname(sc->sc_dev));
#if 0
                        siop_dump(sc);
#ifdef DDB
                        Debugger();
#endif
#endif
#endif
                        rp->siop_dcntl |= SIOP_DCNTL_STD;
                        return(0);
                }
                target = sc->sc_nexus->xs->xs_periph->periph_target;
                rp->siop_temp = 0;
                rp->siop_dsa = kvtop((void *)&sc->sc_nexus->ds);
                rp->siop_sxfer = sc->sc_sync[target].sxfer;
                rp->siop_sbcl = sc->sc_sync[target].sbcl;
                rp->siop_dsp = sc->sc_scriptspa;
                return (0);
        }
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff06) {
                if (acb == NULL)
                        printf("%s: Bad message-in with no active command?\n",
                            device_xname(sc->sc_dev));
                /* Unrecognized message in byte */
                dma_cachectl (&acb->msg[1],1);
                printf ("%s: Unrecognized message in data sfbr %x msg %x sbcl %x\n",
                        device_xname(sc->sc_dev), rp->siop_sfbr, acb->msg[1], rp->siop_sbcl);
                /* what should be done here? */
                DCIAS(kvtop(&acb->msg[1]));
                rp->siop_dsp = sc->sc_scriptspa + Ent_clear_ack;
                return (0);
        }
        if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff0a) {
                /* Status phase wasn't followed by message in phase? */
                printf ("%s: Status phase not followed by message in phase? sbcl %x sbdl %x\n",
                        device_xname(sc->sc_dev), rp->siop_sbcl, rp->siop_sbdl);
                if (rp->siop_sbcl == 0xa7) {
                        /* It is now, just continue the script? */
                        rp->siop_dcntl |= SIOP_DCNTL_STD;
                        return (0);
                }
        }
        if (sstat0 == 0 && dstat & SIOP_DSTAT_SIR) {
                dma_cachectl (&acb->stat[0], 1);
                dma_cachectl (&acb->msg[0], 1);
                printf ("SIOP interrupt: %lx sts %x msg %x %x sbcl %x\n",
                    rp->siop_dsps, acb->stat[0], acb->msg[0], acb->msg[1],
                    rp->siop_sbcl);
                siopreset (sc);
                *status = -1;
                return 0;       /* siopreset has cleaned up */
        }
        if (sstat0 & SIOP_SSTAT0_SGE)
                printf ("SIOP: SCSI Gross Error\n");
        if (sstat0 & SIOP_SSTAT0_PAR)
                printf ("SIOP: Parity Error\n");
        if (dstat & SIOP_DSTAT_IID)
                printf ("SIOP: Invalid instruction detected\n");
bad_phase:
        /*
         * temporary panic for unhandled conditions
         * displays various things about the 53C710 status and registers
         * then panics.
         * XXXX need to clean this up to print out the info, reset, and continue
         */
        printf ("siopchkintr: target %x ds %p\n", target, &acb->ds);
        printf ("scripts %lx ds %x rp %x dsp %lx dcmd %lx\n",
            sc->sc_scriptspa, (unsigned)kvtop((void *)&acb->ds),
            (unsigned)kvtop((void *)__UNVOLATILE(rp)), rp->siop_dsp,
            *((volatile long *)&rp->siop_dcmd));
        printf ("siopchkintr: istat %x dstat %x sstat0 %x dsps %lx dsa %lx sbcl %x sts %x msg %x %x sfbr %x\n",
            istat, dstat, sstat0, rp->siop_dsps, rp->siop_dsa,
             rp->siop_sbcl, acb->stat[0], acb->msg[0], acb->msg[1], rp->siop_sfbr);
#ifdef DEBUG
        if (siop_debug & 0x20)
                panic("siopchkintr: **** temp ****");
#endif
#ifdef DDB
        Debugger ();
#endif
        siopreset (sc);         /* hard reset */
        *status = -1;
        return 0;               /* siopreset cleaned up */
}

void
siop_select(struct siop_softc *sc)
{
        siop_regmap_p rp;
        struct siop_acb *acb = sc->sc_nexus;

#ifdef DEBUG
        if (siop_debug & 1)
                printf ("%s: select ", device_xname(sc->sc_dev));
#endif

        rp = sc->sc_siopp;
        if (acb->xs->xs_control & XS_CTL_POLL || siop_no_dma) {
                sc->sc_flags |= SIOP_INTSOFF;
                sc->sc_flags &= ~SIOP_INTDEFER;
                if ((rp->siop_istat & 0x08) == 0) {
                        rp->siop_sien = 0;
                        rp->siop_dien = 0;
                }
#if 0
        } else if ((sc->sc_flags & SIOP_INTDEFER) == 0) {
                sc->sc_flags &= ~SIOP_INTSOFF;
                if ((rp->siop_istat & 0x08) == 0) {
                        rp->siop_sien = sc->sc_sien;
                        rp->siop_dien = sc->sc_dien;
                }
#endif
        }
#ifdef DEBUG
        if (siop_debug & 1)
                printf ("siop_select: target %x cmd %02x ds %p\n",
                    acb->xs->xs_periph->periph_target, acb->cmd.opcode,
                    &sc->sc_nexus->ds);
#endif

        siop_start(sc, acb->xs->xs_periph->periph_target,
                acb->xs->xs_periph->periph_lun,
            (u_char *)&acb->cmd, acb->clen, acb->daddr, acb->dleft);

        return;
}

/*
 * 53C710 interrupt handler
 */

void
siopintr(register struct siop_softc *sc)
{
        siop_regmap_p rp;
        register u_char istat, dstat, sstat0;
        int status;
        int s = splbio();

        istat = sc->sc_istat;
        if ((istat & (SIOP_ISTAT_SIP | SIOP_ISTAT_DIP)) == 0) {
                splx(s);
                return;
        }

        /* Got a valid interrupt on this device */
        rp = sc->sc_siopp;
        dstat = sc->sc_dstat;
        sstat0 = sc->sc_sstat0;
        if (dstat & SIOP_DSTAT_SIR)
                sc->sc_intcode = rp->siop_dsps;
        sc->sc_istat = 0;
#ifdef DEBUG
        if (siop_debug & 1)
                printf ("%s: intr istat %x dstat %x sstat0 %x\n",
                    device_xname(sc->sc_dev), istat, dstat, sstat0);
        if (!sc->sc_active) {
                printf ("%s: spurious interrupt? istat %x dstat %x sstat0 %x nexus %p status %x\n",
                    device_xname(sc->sc_dev), istat, dstat, sstat0,
                    sc->sc_nexus, sc->sc_nexus ? sc->sc_nexus->stat[0] : 0);
        }
#endif

#ifdef DEBUG
        if (siop_debug & 5) {
                DCIAS(kvtop(&sc->sc_nexus->stat[0]));
                printf ("%s: intr istat %x dstat %x sstat0 %x dsps %lx sbcl %x sts %x msg %x\n",
                    device_xname(sc->sc_dev), istat, dstat, sstat0,
                    rp->siop_dsps,  rp->siop_sbcl,
                    sc->sc_nexus->stat[0], sc->sc_nexus->msg[0]);
        }
#endif
        if (sc->sc_flags & SIOP_INTDEFER) {
                sc->sc_flags &= ~(SIOP_INTDEFER | SIOP_INTSOFF);
                rp->siop_sien = sc->sc_sien;
                rp->siop_dien = sc->sc_dien;
        }
        if (siop_checkintr (sc, istat, dstat, sstat0, &status)) {
#if 1
                if (status == 0xff)
                        printf ("siopintr: status == 0xff\n");
#endif
                if ((sc->sc_flags & (SIOP_INTSOFF | SIOP_INTDEFER)) != SIOP_INTSOFF) {
#if 0
                        if (rp->siop_sbcl & SIOP_BSY) {
                                printf ("%s: SCSI bus busy at completion",
                                        device_xname(sc->sc_dev));
                                printf(" targ %d sbcl %02x sfbr %x lcrc %02x dsp +%x\n",
                                    sc->sc_nexus->xs->xs_periph->periph_target,
                                    rp->siop_sbcl, rp->siop_sfbr, rp->siop_lcrc,
                                    rp->siop_dsp - sc->sc_scriptspa);
                        }
#endif
                        siop_scsidone(sc->sc_nexus, sc->sc_nexus ?
                            sc->sc_nexus->stat[0] : -1);
                }
        }
        splx(s);
}

/*
 * This is based on the Progressive Peripherals 33Mhz Zeus driver and will
 * not be correct for other 53c710 boards.
 *
 */
void
scsi_period_to_siop(struct siop_softc *sc, int target)
{
        int period, offset, sxfer, sbcl = 0;
#ifdef DEBUG_SYNC
        int i;
#endif

        period = sc->sc_nexus->msg[4];
        offset = sc->sc_nexus->msg[5];
#ifdef DEBUG_SYNC
        sxfer = 0;
        if (offset <= SIOP_MAX_OFFSET)
                sxfer = offset;
        for (i = 0; i < sizeof (sync_tab) / 2; ++i) {
                if (period <= sync_tab[i].p) {
                        sxfer |= sync_tab[i].r & 0x70;
                        sbcl = sync_tab[i].r & 0x03;
                        break;
                }
        }
        printf ("siop sync old: siop_sxfr %02x, siop_sbcl %02x\n", sxfer, sbcl);
#endif
        for (sbcl = 1; sbcl < 4; ++sbcl) {
                sxfer = (period * 4 - 1) / sc->sc_tcp[sbcl] - 3;
                if (sxfer >= 0 && sxfer <= 7)
                        break;
        }
        if (sbcl > 3) {
                printf("siop sync: unable to compute sync params for period %dns\n",
                    period * 4);
                /*
                 * XXX need to pick a value we can do and renegotiate
                 */
                sxfer = sbcl = 0;
        } else {
                sxfer = (sxfer << 4) | ((offset <= SIOP_MAX_OFFSET) ?
                    offset : SIOP_MAX_OFFSET);
#ifdef DEBUG_SYNC
                printf("siop sync: params for period %dns: sxfer %x sbcl %x",
                    period * 4, sxfer, sbcl);
                printf(" actual period %dns\n",
                    sc->sc_tcp[sbcl] * ((sxfer >> 4) + 4));
#endif
        }
        sc->sc_sync[target].sxfer = sxfer;
        sc->sc_sync[target].sbcl = sbcl;
#ifdef DEBUG_SYNC
        printf ("siop sync: siop_sxfr %02x, siop_sbcl %02x\n", sxfer, sbcl);
#endif
}

#ifdef DEBUG

#if SIOP_TRACE_SIZE
void
siop_dump_trace(void)
{
        int i;

        printf("siop trace: next index %d\n", siop_trix);
        i = siop_trix;
        do {
                printf("%3d: '%c' %02x %02x %02x\n", i, siop_trbuf[i],
                    siop_trbuf[i + 1], siop_trbuf[i + 2], siop_trbuf[i + 3]);
                i = (i + 4) & (SIOP_TRACE_SIZE - 1);
        } while (i != siop_trix);
}
#endif

void
siop_dump_acb(struct siop_acb *acb)
{
        u_char *b = (u_char *) &acb->cmd;
        int i;

        printf("acb@%p ", acb);
        if (acb->xs == NULL) {
                printf("<unused>\n");
                return;
        }
        printf("(%d:%d) flags %2x clen %2d cmd ",
                acb->xs->xs_periph->periph_target,
            acb->xs->xs_periph->periph_lun, acb->flags, acb->clen);
        for (i = acb->clen; i; --i)
                printf(" %02x", *b++);
        printf("\n");
        printf("  xs: %p data %p:%04x ", acb->xs, acb->xs->data,
            acb->xs->datalen);
        printf("va %p:%lx ", acb->iob_buf, acb->iob_len);
        printf("cur %lx:%lx\n", acb->iob_curbuf, acb->iob_curlen);
}

void
siop_dump(struct siop_softc *sc)
{
        struct siop_acb *acb;
        siop_regmap_p rp = sc->sc_siopp;
        int s;
        int i;

        s = splbio();
#if SIOP_TRACE_SIZE
        siop_dump_trace();
#endif
        printf("%s@%p regs %p istat %x\n",
            device_xname(sc->sc_dev), sc, rp, rp->siop_istat);
        if ((acb = sc->free_list.tqh_first) > 0) {
                printf("Free list:\n");
                while (acb) {
                        siop_dump_acb(acb);
                        acb = acb->chain.tqe_next;
                }
        }
        if ((acb = sc->ready_list.tqh_first) > 0) {
                printf("Ready list:\n");
                while (acb) {
                        siop_dump_acb(acb);
                        acb = acb->chain.tqe_next;
                }
        }
        if ((acb = sc->nexus_list.tqh_first) > 0) {
                printf("Nexus list:\n");
                while (acb) {
                        siop_dump_acb(acb);
                        acb = acb->chain.tqe_next;
                }
        }
        if (sc->sc_nexus) {
                printf("Nexus:\n");
                siop_dump_acb(sc->sc_nexus);
        }
        for (i = 0; i < 8; ++i) {
                if (sc->sc_tinfo[i].cmds > 2) {
                        printf("tgt %d: cmds %d disc %d lubusy %x\n",
                            i, sc->sc_tinfo[i].cmds,
                            sc->sc_tinfo[i].dconns,
                            sc->sc_tinfo[i].lubusy);
                }
        }
        splx(s);
}
#endif