mvme68k port by me. some parts by dale rahn.

1 files changed, 1523 insertions, 0 deletions

diff --git a/sys/arch/mvme68k/dev/siop.c b/sys/arch/mvme68k/dev/siop.c
new file mode 100644
index 00000000000..be0b8b32d9f
--- /dev/null
+++ b/sys/arch/mvme68k/dev/siop.c
@@ -0,0 +1,1523 @@
+/*	$NetBSD: siop.c,v 1.23 1995/08/18 15:28:08 chopps Exp $	*/
+
+/*
+ * Copyright (c) 1994 Michael L. Hitch
+ * 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. 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.
+ *
+ *	@(#)siop.c	7.5 (Berkeley) 5/4/91
+ */
+
+/*
+ * 53C710 scsi adaptor driver
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/disklabel.h>
+#include <sys/dkstat.h>
+#include <sys/buf.h>
+#include <scsi/scsi_all.h>
+#include <scsi/scsiconf.h>
+#include <machine/autoconf.h>
+#include <mvme68k/dev/siopreg.h>
+#include <mvme68k/dev/siopvar.h>
+
+extern u_int	kvtop();
+
+/*
+ * 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 __P((struct siop_softc *));
+void siopabort __P((struct siop_softc *, siop_regmap_p, char *));
+void sioperror __P((struct siop_softc *, siop_regmap_p, u_char));
+void siopstart __P((struct siop_softc *));
+void siopreset __P((struct siop_softc *));
+void siopsetdelay __P((int));
+void siop_scsidone __P((struct siop_acb *, int));
+void siop_sched __P((struct siop_softc *));
+int  siop_poll __P((struct siop_softc *, struct siop_acb *));
+int  siopintr __P((struct siop_softc *));
+
+/* 53C710 script */
+const
+#include <mvme68k/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
+/*
+ *	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;
+#else
+#define SIOP_TRACE(a,b,c,d)
+#endif
+
+
+/*
+ * default minphys routine for siop based controllers
+ */
+void
+siop_minphys(bp)
+	struct buf *bp;
+{
+
+	/*
+	 * No max transfer at this level.
+	 */
+	minphys(bp);
+}
+
+/*
+ * used by specific siop controller
+ *
+ */
+int
+siop_scsicmd(xs)
+	struct scsi_xfer *xs;
+{
+	struct siop_acb *acb;
+	struct siop_softc *sc;
+	struct scsi_link *slp;
+	int flags, s, i;
+
+	slp = xs->sc_link;
+	sc = slp->adapter_softc;
+	flags = xs->flags;
+
+	/* XXXX ?? */
+	if (flags & SCSI_DATA_UIO)
+		panic("siop: scsi data uio requested");
+
+	/* XXXX ?? */
+	if (sc->sc_nexus && flags & SCSI_POLL)
+		panic("siop_scsicmd: busy");
+
+	s = splbio();
+	acb = sc->free_list.tqh_first;
+	if (acb) {
+		TAILQ_REMOVE(&sc->free_list, acb, chain);
+	}
+	splx(s);
+
+	if (acb == NULL) {
+		xs->error = XS_DRIVER_STUFFUP;
+		return(TRY_AGAIN_LATER);
+	}
+
+	acb->flags = ACB_ACTIVE;
+	acb->xs = xs;
+	bcopy(xs->cmd, &acb->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 & SCSI_POLL || siop_no_dma)
+		return(siop_poll(sc, acb));
+	return(SUCCESSFULLY_QUEUED);
+}
+
+int
+siop_poll(sc, acb)
+	struct siop_softc *sc;
+	struct siop_acb *acb;
+{
+	siop_regmap_p rp = sc->sc_siopp;
+	struct scsi_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",
+		    sc->sc_dev.dv_xname);
+	for (;;) {
+		/* use cmd_wait values? */
+		i = 50000;
+		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 %x (+%x) dcmd %x ds %x timeout %d\n",
+				    xs->sc_link->target, acb->cmd.opcode,
+				    rp->siop_sbcl, rp->siop_dsp,
+				    rp->siop_dsp - sc->sc_scriptspa,
+				    *((long *)&rp->siop_dcmd), &acb->ds, acb->xs->timeout);
+#endif
+				i = 50000;
+				--to;
+				if (to <= 0) {
+					siopreset(sc);
+					return(COMPLETE);
+				}
+			}
+			delay(10);
+		}
+		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",
+				    sc->sc_dev.dv_xname);
+			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->flags & ITSDONE)
+			break;
+	}
+	splx(s);
+	return (COMPLETE);
+}
+
+/*
+ * start next command that's ready
+ */
+void
+siop_sched(sc)
+	struct siop_softc *sc;
+{
+	struct scsi_link *slp;
+	struct siop_acb *acb;
+	int stat, i;
+
+#ifdef DEBUG
+	if (sc->sc_nexus) {
+		printf("%s: siop_sched- nexus %x/%d ready %x/%d\n",
+		    sc->sc_dev.dv_xname, sc->sc_nexus,
+		    sc->sc_nexus->xs->sc_link->target,
+		    sc->ready_list.tqh_first,
+		    sc->ready_list.tqh_first->xs->sc_link->target);
+		return;
+	}
+#endif
+	for (acb = sc->ready_list.tqh_first; acb; acb = acb->chain.tqe_next) {
+		slp = acb->xs->sc_link;
+		i = slp->target;
+		if(!(sc->sc_tinfo[i].lubusy & (1 << slp->lun))) {
+			struct siop_tinfo *ti = &sc->sc_tinfo[i];
+
+			TAILQ_REMOVE(&sc->ready_list, acb, chain);
+			sc->sc_nexus = acb;
+			slp = acb->xs->sc_link;
+			ti = &sc->sc_tinfo[slp->target];
+			ti->lubusy |= (1 << slp->lun);
+			break;
+		}
+	}
+
+	if (acb == NULL) {
+#ifdef DEBUGXXX
+		printf("%s: siop_sched didn't find ready command\n",
+		    sc->sc_dev.dv_xname);
+#endif
+		return;
+	}
+
+	if (acb->xs->flags & SCSI_RESET)
+		siopreset(sc);
+
+#if 0
+	acb->cmd.bytes[0] |= slp->lun << 5;	/* XXXX */
+#endif
+	++sc->sc_active;
+	siop_select(sc);
+}
+
+void
+siop_scsidone(acb, stat)
+	struct siop_acb *acb;
+	int stat;
+{
+	struct scsi_xfer *xs = acb->xs;
+	struct scsi_link *slp = xs->sc_link;
+	struct siop_softc *sc = slp->adapter_softc;
+	int s, dosched = 0;
+
+#ifdef DIAGNOSTIC
+	if (acb == NULL || xs == NULL)
+		panic("siop_scsidone");
+#endif
+#if 0
+	if (((struct device *)(slp->device_softc))->dv_unit < dk_ndrive)
+		++dk_xfer[((struct device *)(slp->device_softc))->dv_unit];
+#endif
+	/*
+	 * is this right?
+	 */
+	xs->status = stat;
+
+	if (xs->error == XS_NOERROR && !(acb->flags & ACB_CHKSENSE)) {
+		if (stat == SCSI_CHECK) {
+			struct scsi_sense *ss = (void *)&acb->cmd;
+			bzero(ss, sizeof(*ss));
+			ss->opcode = REQUEST_SENSE;
+			ss->byte2 = slp->lun << 5;
+			ss->length = sizeof(struct scsi_sense_data);
+			acb->clen = sizeof(*ss);
+			acb->daddr = (char *)&xs->sense;
+			acb->dleft = sizeof(struct scsi_sense_data);
+			acb->flags = ACB_ACTIVE | ACB_CHKSENSE;
+			TAILQ_INSERT_HEAD(&sc->ready_list, acb, chain);
+			--sc->sc_active;
+			sc->sc_tinfo[slp->target].lubusy &=
+			    ~(1 << slp->lun);
+			sc->sc_tinfo[slp->target].senses++;
+			if (sc->sc_nexus == acb) {
+				sc->sc_nexus = NULL;
+				siop_sched(sc);
+			}
+			SIOP_TRACE('d','s',0,0)
+			return;
+		}
+	}
+	if (xs->error == XS_NOERROR && (acb->flags & ACB_CHKSENSE)) {
+		xs->error = XS_SENSE;
+	} else {
+		xs->resid = 0;		/* XXXX */
+	}
+#if whataboutthisone
+		case SCSI_BUSY:
+			xs->error = XS_BUSY;
+			break;
+#endif
+	xs->flags |= ITSDONE;
+
+	/*
+	 * 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[slp->target].lubusy &= ~(1<<slp->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[slp->target].lubusy
+					&= ~(1<<slp->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",
+			    sc->sc_dev.dv_xname);
+#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[slp->target].cmds++;
+
+	scsi_done(xs);
+
+	if (dosched && sc->sc_nexus == NULL)
+		siop_sched(sc);
+}
+
+void
+siopabort(sc, rp, where)
+	register struct siop_softc *sc;
+	siop_regmap_p rp;
+	char *where;
+{
+	int i;
+
+	printf ("%s: abort %s: dstat %02x, sstat0 %02x sbcl %02x\n",
+	    sc->sc_dev.dv_xname,
+	    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(sc)
+	struct siop_softc *sc;
+{
+	/*
+	 * Need to check that scripts is on a long word boundary
+	 * and that DS is on a long word boundary.
+	 * Also should verify that dev doesn't span non-contiguous
+	 * physical pages.
+	 */
+	sc->sc_scriptspa = kvtop(scripts);
+	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 not_used
+	if (sc->sc_clock_freq <= 25)
+		sc->sc_tcp[0] = sc->sc_tcp[1];
+	else if (sc->sc_clock_freq <= 37)
+		sc->sc_tcp[0] = sc->sc_tcp[2];
+	else if (sc->sc_clock_freq <= 50)
+		sc->sc_tcp[0] = sc->sc_tcp[3];
+	else
+		sc->sc_tcp[0] = 3000 / sc->sc_clock_freq;
+#endif
+
+	siopreset (sc);
+}
+
+void
+siopreset(sc)
+	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");
+
+	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_link.adapter_target;
+	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 */
+	bzero(&sc->sc_sync, 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;
+
+	splx(s);
+
+	delay(siop_reset_delay * 1000);
+	printf(": version %d target %d\n", rp->siop_ctest8 >> 4,
+	    sc->sc_link.adapter_target);
+
+	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;
+		bzero(acb, sizeof(sc->sc_acb));
+		for (i = 0; i < sizeof(sc->sc_acb) / sizeof(*acb); i++) {
+			TAILQ_INSERT_TAIL(&sc->free_list, acb, chain);
+			acb++;
+		}
+		bzero(sc->sc_tinfo, sizeof(sc->sc_tinfo));
+	} else {
+		if (sc->sc_nexus != NULL) {
+			sc->sc_nexus->xs->error = XS_DRIVER_STUFFUP;
+			siop_scsidone(sc->sc_nexus, sc->sc_nexus->stat[0]);
+		}
+		while (acb = sc->nexus_list.tqh_first) {
+			acb->xs->error = XS_DRIVER_STUFFUP;
+			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 (sc, target, lun, cbuf, clen, buf, len)
+	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 i;
+	int nchain;
+	int count, tcount;
+	char *addr, *dmaend;
+	struct siop_acb *acb = sc->sc_nexus;
+
+#ifdef DEBUG
+	if (siop_debug & 0x100 && rp->siop_sbcl & SIOP_BSY) {
+		printf ("ACK! siop was busy: rp %x script %x dsa %x active %d\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]);
+	bzero(&acb->ds.chain, sizeof (acb->ds.chain));
+
+	if (sc->sc_sync[target].state == SYNC_START) {
+		if (siop_inhibit_sync[target]) {
+			sc->sc_sync[target].state = SYNC_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 = SYNC_SENT;
+#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 = NBPG - ((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] %8x %4x\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 (sc, sizeof (struct siop_softc));
+	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 %x script %x dsa %x active %d\n",
+		    rp, &scripts, &acb->ds, sc->sc_active);
+#ifdef DDB
+		/*Debugger();*/
+#endif
+	}
+#endif
+	if (sc->nexus_list.tqh_first == NULL) {
+		if (rp->siop_istat & SIOP_ISTAT_CON)
+			printf("%s: siop_select while connected?\n",
+			    sc->sc_dev.dv_xname);
+		rp->siop_temp = 0;
+		rp->siop_sbcl = sc->sc_sync[target].sbcl;
+		rp->siop_dsa = kvtop(&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(sc, istat, dstat, sstat0, status)
+	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;
+	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 %x scripts %x:%x",
+		    sc->sc_dev.dv_xname, rp->siop_dsp, sc->sc_scriptspa,
+		    sc->sc_scriptspa + sizeof(scripts));
+		printf(" istat %x dstat %x sstat0 %x\n",
+		    istat, dstat, sstat0);
+		Debugger();
+	}
+#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(&acb->ds)) {
+			printf ("siop: invalid dsa: %x %x\n", rp->siop_dsa,
+			    kvtop(&acb->ds));
+			panic("*** siop DSA invalid ***");
+		}
+#endif
+		target = acb->xs->sc_link->target;
+		if (sc->sc_sync[target].state == SYNC_SENT) {
+#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
+			if (acb->msg[1] == 0xff)
+				printf ("%s: target %d ignored sync request\n",
+				    sc->sc_dev.dv_xname, target);
+			else if (acb->msg[1] == MSG_REJECT)
+				printf ("%s: target %d rejected sync request\n",
+				    sc->sc_dev.dv_xname, target);
+			sc->sc_sync[target].state = SYNC_DONE;
+			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",
+					    sc->sc_dev.dv_xname, 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",
+				    sc->sc_dev.dv_xname, target,
+				    acb->msg[4] * 4, acb->msg[5]);
+				scsi_period_to_siop (sc, target);
+			}
+		}
+		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",
+			    sc->sc_dev.dv_xname, acb->msg[0]);
+#endif
+		if (sc->nexus_list.tqh_first)
+			rp->siop_dcntl |= SIOP_DCNTL_STD;
+		return 1;
+	}
+	if (sstat0 & SIOP_SSTAT0_M_A) {		/* Phase mismatch */
+#ifdef DEBUG
+		++siopphmm;
+		if (acb == NULL)
+			printf("%s: Phase mismatch with no active command?\n",
+			    sc->sc_dev.dv_xname);
+#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 *)&rp->siop_dcmd) & 0xffffff;
+			acb->iob_curlen += adjust;
+			acb->iob_curbuf = *((long *)&rp->siop_dnad) - adjust;
+#ifdef DEBUG
+			if (siop_debug & 0x100) {
+				int i;
+				printf ("Phase mismatch: curbuf %x curlen %x dfifo %x dbc %x sstat1 %x adjust %x sbcl %x starts %d acb %x\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 %x len %x\n",
+						    i, acb->ds.chain[i].databuf,
+						    acb->ds.chain[i].datalen);
+				}
+			}
+#endif
+			dma_cachectl (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 +%x dcmd %x\n",
+			    rp->siop_sbcl,
+			    rp->siop_dsp - sc->sc_scriptspa,
+			    *((long *)&rp->siop_dcmd));
+#endif
+		if ((rp->siop_sbcl & SIOP_REQ) == 0) {
+			printf ("Phase mismatch: REQ not asserted! %02x dsp %x\n",
+			    rp->siop_sbcl, rp->siop_dsp);
+#ifdef DEBUG
+			Debugger();
+#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",
+			    sc->sc_dev.dv_xname);
+		if (rp->siop_sbcl & SIOP_BSY) {
+			printf ("ACK! siop was busy at timeout: rp %x script %x dsa %x\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);
+#ifdef DDB
+			Debugger();
+#endif
+		}
+#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->sc_link->target;
+	else
+		target = 7;
+	if (sstat0 & SIOP_SSTAT0_UDC) {
+#ifdef DEBUG
+		if (acb == NULL)
+			printf("%s: Unexpected disconnect with no active command?\n",
+			    sc->sc_dev.dv_xname);
+		printf ("%s: target %d disconnected unexpectedly\n",
+		   sc->sc_dev.dv_xname, 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 1;
+	}
+	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 %x (+%x) curbuf %x curlen %x buf %x len %x dfifo %x dbc %x sstat1 %x starts %d acb %x\n",
+			    sc->sc_dev.dv_xname, 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",
+			    sc->sc_dev.dv_xname);
+			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 %x/%x chain[0] %x/%x\n",
+				    sc->sc_dev.dv_xname, 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", sc->sc_dev.dv_xname, n);
+				printf(" curbuf %x curlen %x\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",
+				    sc->sc_dev.dv_xname);
+			if (rp->siop_dsps == 0xff02)
+				printf ("%s: ID %02x disconnected without Save Data Pointers\n",
+				    sc->sc_dev.dv_xname, 1 << target);
+#endif
+			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\n");
+#ifdef DEBUG
+			if (siop_debug & 0x100)
+				printf("  chain[0]: %x/%x -> %x/%x\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]: %x/%x -> %x/%x\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(&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 %x\n",
+			     sc->sc_dev.dv_xname, reselid,
+			     rp->siop_dsps);
+		if ((rp->siop_sfbr & 0x80) == 0)
+			printf("%s: Reselect message in was not identify: %x\n",
+			    sc->sc_dev.dv_xname, rp->siop_sfbr);
+#endif
+		if (sc->sc_nexus) {
+#ifdef DEBUG
+			if (siop_debug & 0x100)
+				printf ("%s: reselect ID %02x w/active\n",
+				    sc->sc_dev.dv_xname, reselid);
+#endif
+			TAILQ_INSERT_HEAD(&sc->ready_list, sc->sc_nexus, chain);
+			sc->sc_tinfo[sc->sc_nexus->xs->sc_link->target].lubusy
+			    &= ~(1 << sc->sc_nexus->xs->sc_link->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(&acb->ds);
+			rp->siop_sxfer = sc->sc_sync[acb->xs->sc_link->target].sxfer;
+			rp->siop_sbcl = sc->sc_sync[acb->xs->sc_link->target].sbcl;
+			break;
+		}
+		if (acb == NULL) {
+			printf("%s: target ID %02x reselect nexus_list %x\n",
+			    sc->sc_dev.dv_xname, reselid,
+			    sc->nexus_list.tqh_first);
+			panic("unable to find reselecting device");
+		}
+		dma_cachectl (acb, sizeof(*acb));
+		rp->siop_temp = 0;
+		rp->siop_dcntl |= SIOP_DCNTL_STD;
+		return (0);
+	}
+	if (dstat & SIOP_DSTAT_SIR && rp->siop_dsps == 0xff04) {
+		u_short ctest2 = rp->siop_ctest2;
+
+		/* reselect was interrupted (by Sig_P or select) */
+#ifdef DEBUG
+		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",
+			    sc->sc_dev.dv_xname, rp->siop_scntl1,
+			    ctest2, rp->siop_sfbr, istat, rp->siop_istat);
+#endif
+		/* XXX assumes it was not select */
+		if (sc->sc_nexus == NULL) {
+			printf("%s: reselect interrupted, sc_nexus == NULL\n",
+			    sc->sc_dev.dv_xname);
+#if 0
+			siop_dump(sc);
+#ifdef DDB
+			Debugger();
+#endif
+#endif
+			rp->siop_dcntl |= SIOP_DCNTL_STD;
+			return(0);
+		}
+		target = sc->sc_nexus->xs->sc_link->target;
+		rp->siop_temp = 0;
+		rp->siop_dsa = kvtop(&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",
+			    sc->sc_dev.dv_xname);
+		/* Unrecognized message in byte */
+		dma_cachectl (&acb->msg[1],1);
+		printf ("%s: Unrecognized message in data sfbr %x msg %x sbcl %x\n",
+			sc->sc_dev.dv_xname, 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_switch;
+		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",
+			sc->sc_dev.dv_xname, 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: %x 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 %x\n", target, &acb->ds);
+	printf ("scripts %x ds %x rp %x dsp %x dcmd %x\n", sc->sc_scriptspa,
+	    kvtop(&acb->ds), kvtop(rp), rp->siop_dsp,
+	    *((long *)&rp->siop_dcmd));
+	printf ("siopchkintr: istat %x dstat %x sstat0 %x dsps %x dsa %x 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(sc)
+	struct siop_softc *sc;
+{
+	siop_regmap_p rp;
+	struct siop_acb *acb = sc->sc_nexus;
+
+#ifdef DEBUG
+	if (siop_debug & 1)
+		printf ("%s: select ", sc->sc_dev.dv_xname);
+#endif
+
+	rp = sc->sc_siopp;
+	if (acb->xs->flags & SCSI_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 %x\n",
+		    acb->xs->sc_link->target, acb->cmd.opcode,
+		    &sc->sc_nexus->ds);
+#endif
+
+	siop_start(sc, acb->xs->sc_link->target, acb->xs->sc_link->lun,
+	    &acb->cmd, acb->clen, acb->daddr, acb->dleft);
+
+	return;
+}
+
+/*
+ * 53C710 interrupt handler
+ */
+
+int
+siopintr (sc)
+	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",
+		    sc->sc_dev.dv_xname, istat, dstat, sstat0);
+	if (!sc->sc_active) {
+		printf ("%s: spurious interrupt? istat %x dstat %x sstat0 %x status %x\n",
+		    sc->sc_dev.dv_xname, istat, dstat, sstat0, sc->sc_nexus->stat[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 %x sbcl %x sts %x msg %x\n",
+		    sc->sc_dev.dv_xname, 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",
+					sc->sc_dev.dv_xname);
+				printf(" targ %d sbcl %02x sfbr %x lcrc %02x dsp +%x\n",
+				    sc->sc_nexus->xs->sc_link->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->stat[0]);
+		}
+	}
+	splx(s);
+}
+
+/*
+ * This is based on the Progressive Peripherals 33Mhz Zeus driver and will
+ * not be correct for other 53c710 boards.
+ *
+ */
+scsi_period_to_siop (sc, target)
+	struct siop_softc *sc;
+{
+	int period, offset, i, sxfer, sbcl;
+
+	period = sc->sc_nexus->msg[4];
+	offset = sc->sc_nexus->msg[5];
+	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);
+	sc->sc_sync[target].sxfer = sxfer;
+	sc->sc_sync[target].sbcl = sbcl;
+#ifdef DEBUG
+	printf ("siop sync: siop_sxfr %02x, siop_sbcl %02x\n", sxfer, sbcl);
+#endif
+}
+
+#ifdef DEBUG
+
+#if SIOP_TRACE_SIZE
+void
+siop_dump_trace()
+{
+	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(acb)
+	struct siop_acb *acb;
+{
+	u_char *b = (u_char *) &acb->cmd;
+	int i;
+
+#if SIOP_TRACE_SIZE
+	siop_dump_trace();
+#endif
+	printf("acb@%x ", acb);
+	if (acb->xs == NULL) {
+		printf("<unused>\n");
+		return;
+	}
+	printf("(%d:%d) flags %2x clen %2d cmd ", acb->xs->sc_link->target,
+	    acb->xs->sc_link->lun, acb->flags, acb->clen);
+	for (i = acb->clen; i; --i)
+		printf(" %02x", *b++);
+	printf("\n");
+	printf("  xs: %08x data %8x:%04x ", acb->xs, acb->xs->data,
+	    acb->xs->datalen);
+	printf("va %8x:%04x ", acb->iob_buf, acb->iob_len);
+	printf("cur %8x:%04x\n", acb->iob_curbuf, acb->iob_curlen);
+  }
+
+void
+siop_dump(sc)
+	struct siop_softc *sc;
+{
+	struct siop_acb *acb;
+	siop_regmap_p rp = sc->sc_siopp;
+	int s;
+	int i;
+
+	s = splbio();
+	printf("%s@%x regs %x istat %x\n",
+	    sc->sc_dev.dv_xname, sc, rp, rp->siop_istat);
+	if (acb = sc->free_list.tqh_first) {
+		printf("Free list:\n");
+		while (acb) {
+			siop_dump_acb(acb);
+			acb = acb->chain.tqe_next;
+		}
+	}
+	if (acb = sc->ready_list.tqh_first) {
+		printf("Ready list:\n");
+		while (acb) {
+			siop_dump_acb(acb);
+			acb = acb->chain.tqe_next;
+		}
+	}
+	if (acb = sc->nexus_list.tqh_first) {
+		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 senses %d lubusy %x\n",
+			    i, sc->sc_tinfo[i].cmds,
+			    sc->sc_tinfo[i].dconns,
+			    sc->sc_tinfo[i].senses,
+			    sc->sc_tinfo[i].lubusy);
+		}
+	}
+	splx(s);
+}
+#endif