xref: /src/sys/arch/mvme68k/dev/sbic.c

/*	$NetBSD: sbic.c,v 1.37 2024/09/08 09:36:49 rillig Exp $	*/

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

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

/*
 * Steve Woodford (SCW), Apr, 1996
 * MVME147S WD33C93 Scsi Bus Interface Controller driver,
 *
 * Basically a de-loused and tidied up version of the Amiga AMD 33C93 driver.
 *
 * The original driver used features which required at least a WD33C93A
 * chip. The '147 has the original WD33C93 chip (no 'A' suffix).
 *
 * This version of the driver is pretty well generic, so should work with
 * any flavour of WD33C93 chip.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sbic.c,v 1.37 2024/09/08 09:36:49 rillig Exp $");

#include "opt_ddb.h"

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

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

#include <uvm/uvm_extern.h>

#include <mvme68k/mvme68k/isr.h>
#include <mvme68k/dev/dmavar.h>
#include <mvme68k/dev/sbicreg.h>
#include <mvme68k/dev/sbicvar.h>


/*
 * Since I can't find this in any other header files
 */
#define SCSI_PHASE(reg) (reg&0x07)

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

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

int     sbicicmd            (struct sbic_softc *, void *, int, void *, int);
int     sbicgo              (struct sbic_softc *, struct scsipi_xfer *);
int     sbicdmaok           (struct sbic_softc *, struct scsipi_xfer *);
int     sbicwait            (sbic_regmap_p, u_char, int , int);
int     sbiccheckdmap       (void *, u_long, u_long);
u_char  sbicselectbus       (struct sbic_softc *);
int     sbicxfout           (sbic_regmap_p, int, void *);
int     sbicxfin            (sbic_regmap_p, int, void *);
int     sbicfromscsiperiod  (struct sbic_softc *, int);
int     sbictoscsiperiod    (struct sbic_softc *, int);
int     sbicpoll            (struct sbic_softc *);
int     sbicnextstate       (struct sbic_softc *, u_char, u_char);
int     sbicmsgin           (struct sbic_softc *);
int     sbicabort           (struct sbic_softc *, const char *);
void    sbicxfdone          (struct sbic_softc *);
void    sbicerror           (struct sbic_softc *, u_char);
void    sbicreset           (struct sbic_softc *);
void    sbic_scsidone       (struct sbic_acb *, int);
void    sbic_sched          (struct sbic_softc *);
void    sbic_save_ptrs      (struct sbic_softc *);
void    sbic_load_ptrs      (struct sbic_softc *);

/*
 * Synch xfer parameters, and timing conversions
 */
int     sbic_min_period = SBIC_SYN_MIN_PERIOD;  /* in cycles = f(ICLK,FSn) */
int     sbic_max_offset = SBIC_SYN_MAX_OFFSET;  /* pure number */
int     sbic_cmd_wait   = SBIC_CMD_WAIT;
int     sbic_data_wait  = SBIC_DATA_WAIT;
int     sbic_init_wait  = SBIC_INIT_WAIT;

/*
 * was broken before.. now if you want this you get it for all drives
 * on sbic controllers.
 */
u_char  sbic_inhibit_sync[8];
int     sbic_enable_reselect     = 1;   /* Allow Disconnect / Reselect */
int     sbic_no_dma              = 0;   /* Use PIO transfers instead of DMA */
int     sbic_parallel_operations = 1;   /* Allow command queues */

/*
 * Some useful stuff for debugging purposes
 */
#ifdef DEBUG
int     sbicdma_ops     = 0;    /* total DMA operations */
int     sbicdma_hits    = 0;    /* number of DMA chains that were contiguous */
int     sbicdma_misses  = 0;    /* number of DMA chains that were not contiguous */
int     sbicdma_saves   = 0;

#define QPRINTF(a) if (sbic_debug > 1) printf a

int     sbic_debug      = 0;    /* Debug all chip related things */
int     sync_debug      = 0;    /* Debug all Synchronous Scsi related things */
int     reselect_debug  = 0;    /* Debug all reselection related things */
int     data_pointer_debug = 0; /* Debug Data Pointer related things */

void    sbictimeout(struct sbic_softc *dev);

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


/*
 * default minphys routine for sbic based controllers
 */
void
sbic_minphys(struct buf *bp)
{
	/*
	 * No max transfer at this level.
	 */
	minphys(bp);
}


/*
 * Save DMA pointers.  Take into account partial transfer. Shut down DMA.
 */
void
sbic_save_ptrs(struct sbic_softc *dev)
{
	sbic_regmap_p regs;
	struct sbic_acb *acb;
	int count, asr, s;

	/*
	 * Only need to save pointers if DMA was active...
	 */
	if (dev->sc_cur == NULL || (dev->sc_flags & SBICF_INDMA) == 0)
		return;

	regs = dev->sc_sbicp;

	s = splbio();

	/*
	 * Wait until WD chip is idle
	 */
	do {
		GET_SBIC_asr(regs, asr);
		if (asr & SBIC_ASR_DBR) {
			printf("%s: asr %02x canceled!\n", __func__, asr);
			splx(s);
			return;
		}
	} while(asr & (SBIC_ASR_BSY|SBIC_ASR_CIP));


	/*
	 * Save important state.
	 * must be done before dmastop
	 */
	acb            = dev->sc_nexus;
	acb->sc_dmacmd = dev->sc_dmacmd;

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

	/*
	 * Shut down DMA
	 */
	dev->sc_dmastop(dev);

	/*
	 * No longer in DMA
	 */
	dev->sc_flags &= ~SBICF_INDMA;

	/*
	 * Ensure the WD chip is back in polled I/O mode, with nothing to
	 * transfer.
	 */
	SBIC_TC_PUT(regs, 0);
	SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);

	/*
	 * Update current count...
	 */
	acb->sc_tcnt = count;

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

	/*
	 * Fixup partial xfers
	 */
	acb->sc_kv.dc_addr  += count;
	acb->sc_kv.dc_count -= count;
	acb->sc_pa.dc_addr  += count;
	acb->sc_pa.dc_count -= count >> 1;

#ifdef DEBUG
	if (data_pointer_debug)
		printf("save at (%p,%x):%x\n",
		    dev->sc_cur->dc_addr, dev->sc_cur->dc_count,count);
	sbicdma_saves++;
#endif

	splx(s);
}


/*
 * DOES NOT RESTART DMA!!!
 */
void
sbic_load_ptrs(struct sbic_softc *dev)
{
	struct sbic_acb *acb = dev->sc_nexus;
	int s;

	if (acb->sc_kv.dc_count == 0) {
		/*
		 * No data to xfer
		 */
		return;
	}

	s = splbio();

	/*
	 * Reset the Scatter-Gather chain
	 */
	dev->sc_last = dev->sc_cur = &acb->sc_pa;

	/*
	 * Restore the Transfer Count and DMA specific data
	 */
	dev->sc_tcnt   = acb->sc_tcnt;
	dev->sc_dmacmd = acb->sc_dmacmd;

#ifdef DEBUG
	sbicdma_ops++;
#endif

	/*
	 * Need to fixup new segment?
	 */
	if (dev->sc_tcnt == 0) {
		/*
		 * sc_tcnt == 0 implies end of segment
		 */
		char *vaddr, *paddr;
		int count;

		/*
		 * do kvm to pa mappings
		 */
		vaddr = acb->sc_kv.dc_addr;
		paddr = acb->sc_pa.dc_addr = (char *)kvtop((void *)vaddr);

		for (count = (PAGE_SIZE - ((int)vaddr & PGOFSET));
		    count < acb->sc_kv.dc_count &&
		    (char *)kvtop((void *)(vaddr + count + 4)) ==
		    paddr + count + 4;
		    count += PAGE_SIZE)
			;	/* Do nothing */

		/*
		 * If it's all contiguous...
		 */
		if (count > acb->sc_kv.dc_count) {
			count = acb->sc_kv.dc_count;
#ifdef DEBUG
			sbicdma_hits++;
#endif
		}
#ifdef  DEBUG
		else
			sbicdma_misses++;
#endif

		acb->sc_tcnt        = count;
		acb->sc_pa.dc_count = count >> 1;

#ifdef DEBUG
		if (data_pointer_debug)
			printf("DMA recalc:kv(%p,%x)pa(%p,%lx)\n",
			    acb->sc_kv.dc_addr,
                            acb->sc_kv.dc_count,
                            acb->sc_pa.dc_addr,
                            acb->sc_tcnt);
#endif

	}

	splx(s);
}

/*
 * used by specific sbic controller
 *
 * it appears that the higher level code does nothing with LUN's
 * so I will too.  I could plug it in, however so could they
 * in scsi_scsipi_cmd().
 */
void
sbic_scsi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
    void *arg)
{
	struct scsipi_xfer *xs;
	struct scsipi_periph *periph;
	struct sbic_softc *dev = device_private(chan->chan_adapter->adapt_dev);
	struct sbic_acb *acb;
	int flags, s;

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

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

		if (dev->sc_nexus && (flags & XS_CTL_POLL))
			panic("sbic_scsicmd: busy");

		s = splbio();

		if ((acb = dev->free_list.tqh_first) != NULL)
			TAILQ_REMOVE(&dev->free_list, acb, chain);

		splx(s);

		if (acb == NULL) {
#ifdef DEBUG
			printf("%s: unable to queue request for target %d\n",
			    __func__, periph->periph_target);
#ifdef DDB
			Debugger();
#endif
#endif
			xs->error = XS_RESOURCE_SHORTAGE;
			scsipi_done(xs);
			return;
		}

		if (flags & XS_CTL_DATA_IN)
			acb->flags = ACB_ACTIVE | ACB_DATAIN;
		else
			acb->flags = ACB_ACTIVE;

		acb->xs             = xs;
		acb->clen           = xs->cmdlen;
		acb->sc_kv.dc_addr  = xs->data;
		acb->sc_kv.dc_count = xs->datalen;
		acb->pa_addr        = xs->data ?
		    (char *)kvtop((void *)xs->data) : 0;
		memcpy(&acb->cmd, xs->cmd, xs->cmdlen);

		if (flags & XS_CTL_POLL) {
			/*
			 * This has major side effects
			 * -- it locks up the machine
			 */
			int stat;

			s = splbio();

			dev->sc_flags |= SBICF_ICMD;

			do {
				/*
				 * If we already had a nexus, while away
				 * the time until idle...
				 * This is likely only to happen if
				 * a reselection occurs between
				 * here and our earlier check for
				 * ICMD && sc_nexus(which would
				 * have resulted in a panic() had it been true).
				 */
				while (dev->sc_nexus)
					sbicpoll(dev);

				/*
				 * Fix up the new nexus
				 */
				dev->sc_nexus   = acb;
				dev->sc_xs      = xs;
				dev->target     = periph->periph_target;
				dev->lun        = periph->periph_lun;

				stat = sbicicmd(dev, &acb->cmd, acb->clen,
				    acb->sc_kv.dc_addr, acb->sc_kv.dc_count);

			} while (dev->sc_nexus != acb);

			sbic_scsidone(acb, stat);

			splx(s);

			return;
		}

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

		/*
		 * If nothing is active, try to start it now.
		 */
		if (dev->sc_nexus == NULL)
			sbic_sched(dev);

		splx(s);

		return;

	case ADAPTER_REQ_GROW_RESOURCES:
		/* XXX Not supported. */
		return;

	case ADAPTER_REQ_SET_XFER_MODE:
		/* XXX Not supported. */
		return;
	}
}

/*
 * attempt to start the next available command
 */
void
sbic_sched(struct sbic_softc *dev)
{
	struct scsipi_xfer *xs;
	struct scsipi_periph  *periph = NULL;	/* Gag the compiler */
	struct sbic_acb *acb;
	int flags, stat;

	/*
	 * XXXSCW
	 * I'll keep this test here, even though I can't see any obvious way
	 * in which sbic_sched() could be called with sc_nexus non NULL
	 */
	if (dev->sc_nexus)
		return;		/* a command is current active */

	/*
	 * Loop through the ready list looking for work to do...
	 */
	for (acb = dev->ready_list.tqh_first; acb; acb = acb->chain.tqe_next) {
		int i, j;

		periph = acb->xs->xs_periph;
		i = periph->periph_target;
		j = 1 << periph->periph_lun;

		/*
		 * We've found a potential command, but is the target/lun busy?
		 */
		if ((dev->sc_tinfo[i].lubusy & j) == 0) {
			/*
			 * Nope, it's not busy, so we can use it.
			 */
			dev->sc_tinfo[i].lubusy |= j;
			TAILQ_REMOVE(&dev->ready_list, acb, chain);
			dev->sc_nexus = acb;
			acb->sc_pa.dc_addr = acb->pa_addr;  /* XXXX check */
			break;
		}
	}

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

#ifdef DEBUG
	if (data_pointer_debug > 1)
		printf("sbic_sched(%d,%d)\n", periph->periph_target,
		    periph->periph_lun);
#endif

	dev->sc_xs = xs = acb->xs;
	flags      = xs->xs_control;

	if (flags & XS_CTL_RESET)
		sbicreset(dev);

	dev->sc_stat[0] = -1;
	dev->target     = periph->periph_target;
	dev->lun        = periph->periph_lun;

	if (flags & XS_CTL_POLL || (!sbic_parallel_operations &&
	    (sbicdmaok(dev, xs) == 0)) )
		stat = sbicicmd(dev, &acb->cmd, acb->clen,
		    acb->sc_kv.dc_addr, acb->sc_kv.dc_count);
	else if (sbicgo(dev, xs) == 0 && xs->error != XS_SELTIMEOUT)
	        return;
	else
		stat = dev->sc_stat[0];

	sbic_scsidone(acb, stat);
}

void
sbic_scsidone(struct sbic_acb *acb, int stat)
{
	struct scsipi_xfer *xs  = acb->xs;
	struct scsipi_periph  *periph = xs->xs_periph;
	struct sbic_softc *dev =
	    device_private(periph->periph_channel->chan_adapter->adapt_dev);
	int dosched = 0;

#ifdef DIAGNOSTIC
	if (acb == NULL || xs == NULL) {
		printf("sbic_scsidone -- (%d,%d) no scsipi_xfer\n",
		    dev->target, dev->lun);
#ifdef DDB
		Debugger();
#endif
		return;
	}
#endif


#ifdef DEBUG
	if (data_pointer_debug > 1)
		printf("scsidone: (%d,%d)->(%d,%d)%02x\n",
		    periph->periph_target, periph->periph_lun,
		    dev->target, dev->lun, stat);

	if (xs->xs_periph->periph_target == dev->sc_channel.chan_id)
		panic("target == hostid");
#endif

	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 == dev->sc_nexus ) {

		dev->sc_nexus = NULL;
		dev->sc_xs    = NULL;

		dev->sc_tinfo[periph->periph_target].lubusy &=
		    ~(1 << periph->periph_lun);

		if (dev->ready_list.tqh_first)
			dosched = 1;	/* start next command */

	} else if (dev->ready_list.tqh_last == &acb->chain.tqe_next) {

		TAILQ_REMOVE(&dev->ready_list, acb, chain);

	} else {

		struct sbic_acb *a;

		for (a = dev->nexus_list.tqh_first; a != NULL;
		    a = a->chain.tqe_next) {
			if (a == acb) {
				TAILQ_REMOVE(&dev->nexus_list, acb, chain);
				dev->sc_tinfo[periph->periph_target].lubusy &=
				    ~(1 << periph->periph_lun);
				break;
			}
		}

		if (a != NULL)
			;
		else if ( acb->chain.tqe_next ) {
			TAILQ_REMOVE(&dev->ready_list, acb, chain);
		} else {
			printf("%s: can't find matching acb\n",
			    device_xname(dev->sc_dev));
#ifdef DDB
			Debugger();
#endif
		}
	}

	/*
	 * Put it on the free list.
	 */
	acb->flags = ACB_FREE;
	TAILQ_INSERT_HEAD(&dev->free_list, acb, chain);

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

	scsipi_done(xs);

	if (dosched)
		sbic_sched(dev);
}

int
sbicdmaok(struct sbic_softc *dev, struct scsipi_xfer *xs)
{

	if (sbic_no_dma || xs->datalen == 0 ||
	    xs->datalen & 0x03 || (int)xs->data & 0x03)
		return 0;

	/*
	 * controller supports DMA to any addresses?
	 */
	if ((dev->sc_flags & SBICF_BADDMA) == 0)
		return 1;

	/*
	 * this address is ok for DMA?
	 */
	if (sbiccheckdmap(xs->data, xs->datalen, dev->sc_dmamask) == 0)
		return 1;

	return 0;
}

int
sbicwait(sbic_regmap_p regs, u_char until, int timeo, int line)
{
	u_char  val;

	if (timeo == 0)
		timeo = 1000000;	/* some large value.. */

	GET_SBIC_asr(regs, val);

	while ((val & until) == 0) {

		if (timeo-- == 0) {
			int csr;
			GET_SBIC_csr(regs, csr);
			printf("sbicwait TIMEO @%d with asr=x%x csr=x%x\n",
			    line, val, csr);
#if defined(DDB) && defined(DEBUG)
			Debugger();
#endif
			return val;	/* Maybe I should abort */
			break;
		}

		DELAY(1);
		GET_SBIC_asr(regs, val);
	}

	return val;
}

int
sbicabort(struct sbic_softc *dev, const char *where)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_char csr, asr;

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

	printf ("%s: abort %s: csr = 0x%02x, asr = 0x%02x\n",
	    device_xname(dev->sc_dev), where, csr, asr);

	/*
	 * Clean up chip itself
	 */
	if (dev->sc_flags & SBICF_SELECTED) {

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

		WAIT_CIP(regs);

		printf("%s: sbicabort - sending ABORT command\n",
		    device_xname(dev->sc_dev));
		SET_SBIC_cmd(regs, SBIC_CMD_ABORT);
		WAIT_CIP(regs);

		GET_SBIC_asr(regs, asr);

		if (asr & (SBIC_ASR_BSY|SBIC_ASR_LCI)) {
			/*
			 * ok, get more drastic..
			 */
			printf("%s: sbicabort - asr %x, trying to reset\n",
			    device_xname(dev->sc_dev), asr);
			sbicreset(dev);
			dev->sc_flags &= ~SBICF_SELECTED;
			return SBIC_STATE_ERROR;
		}

		printf("%s: sbicabort - sending DISC command\n",
		    device_xname(dev->sc_dev));
		SET_SBIC_cmd(regs, SBIC_CMD_DISC);

		do {
			SBIC_WAIT (regs, SBIC_ASR_INT, 0);
			GET_SBIC_asr(regs, asr);
			GET_SBIC_csr (regs, csr);
			QPRINTF(("csr: 0x%02x, asr: 0x%02x\n", csr, asr));
		} while ((csr != SBIC_CSR_DISC) && (csr != SBIC_CSR_DISC_1) &&
		    (csr != SBIC_CSR_CMD_INVALID));

		/*
		 * lets just hope it worked..
		 */
		dev->sc_flags &= ~SBICF_SELECTED;
	}

	return SBIC_STATE_ERROR;
}


/*
 * Initialize driver-private structures
 */
void
sbicinit(struct sbic_softc *dev)
{
	u_int i;

	if ((dev->sc_flags & SBICF_ALIVE) == 0) {

		struct sbic_acb *acb;

		TAILQ_INIT(&dev->ready_list);
		TAILQ_INIT(&dev->nexus_list);
		TAILQ_INIT(&dev->free_list);
		callout_init(&dev->sc_timo_ch, 0);

		dev->sc_nexus = NULL;
		dev->sc_xs    = NULL;

		acb = dev->sc_acb;
		memset(acb, 0, sizeof(dev->sc_acb));

		for (i = 0; i < sizeof(dev->sc_acb) / sizeof(*acb); i++) {
			TAILQ_INSERT_TAIL(&dev->free_list, acb, chain);
			acb++;
		}

		memset(dev->sc_tinfo, 0, sizeof(dev->sc_tinfo));

#ifdef DEBUG
		/*
		 * make sure timeout is really not needed
		 */
		callout_reset(&dev->sc_timo_ch, 30 * hz,
		    (void *)sbictimeout, dev);
#endif

	} else
		panic("sbic: reinitializing driver!");

	dev->sc_flags |=  SBICF_ALIVE;
	dev->sc_flags &= ~SBICF_SELECTED;

	/*
	 * initialize inhibit array
	 * Never enable Sync, since it just doesn't work on mvme147 :(
	 */
	for (i = 0; i < 8; ++i)
		sbic_inhibit_sync[i] = 1;

	sbicreset(dev);
}

void
sbicreset(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_int my_id, s;
	u_char csr;

	s = splbio();

	my_id = dev->sc_channel.chan_id & SBIC_ID_MASK;

	if (dev->sc_clkfreq < 110)
		my_id |= SBIC_ID_FS_8_10;
	else if (dev->sc_clkfreq < 160)
		my_id |= SBIC_ID_FS_12_15;
	else if (dev->sc_clkfreq < 210)
		my_id |= SBIC_ID_FS_16_20;

	SET_SBIC_myid(regs, my_id);

	/*
	 * Reset the chip
	 */
	SET_SBIC_cmd(regs, SBIC_CMD_RESET);
	DELAY(25);

	SBIC_WAIT(regs, SBIC_ASR_INT, 0);
	GET_SBIC_csr(regs, csr);	/* clears interrupt also */
	__USE(csr);

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

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

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

	/*
	 * Anything else was zeroed by reset
	 */
	splx(s);

	dev->sc_flags &= ~SBICF_SELECTED;
}

void
sbicerror(struct sbic_softc *dev, u_char csr)
{
	struct scsipi_xfer *xs  = dev->sc_xs;

#ifdef DIAGNOSTIC
	if (xs == NULL)
		panic("sbicerror: dev->sc_xs == NULL");
#endif

	if ( xs->xs_control & XS_CTL_SILENT )
		return;

	printf("%s: csr == 0x%02x\n", device_xname(dev->sc_dev), csr);
}

/*
 * select the bus, return when selected or error.
 *
 * Returns the current CSR following selection and optionally MSG out phase.
 * i.e. the returned CSR *should* indicate CMD phase...
 * If the return value is 0, some error happened.
 */
u_char
sbicselectbus(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_char target = dev->target, lun = dev->lun, asr, csr, id;

	/*
	 * if we're already selected, return (XXXX panic maybe?)
	 */
	if (dev->sc_flags & SBICF_SELECTED)
		return 0;

	QPRINTF(("sbicselectbus %d: ", target));

	/*
	 * issue select
	 */
	SET_SBIC_selid(regs, target);
	SET_SBIC_timeo(regs, SBIC_TIMEOUT(250, dev->sc_clkfreq));

	GET_SBIC_asr(regs, asr);

	if (asr & (SBIC_ASR_INT|SBIC_ASR_BSY)) {
		/*
		 * This means we got ourselves reselected upon
		 */
		QPRINTF(("WD busy (reselect?)\n"));
		return 0;
	}

	SET_SBIC_cmd(regs, SBIC_CMD_SEL_ATN);

	/*
	 * wait for select (merged from separate function may need
	 * cleanup)
	 */
	WAIT_CIP(regs);

	do {

		asr = SBIC_WAIT(regs, SBIC_ASR_INT | SBIC_ASR_LCI, 0);

		if (asr & SBIC_ASR_LCI) {
			QPRINTF(("late LCI: asr %02x\n", asr));
			return 0;
		}

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

		QPRINTF(("%02x ", csr));

		/*
		 * Reselected from under our feet?
		 */
		if (csr == SBIC_CSR_RSLT_NI || csr == SBIC_CSR_RSLT_IFY) {
			QPRINTF(("got reselected, asr %02x\n", asr));
			/*
			 * We need to handle this now so we don't lock up later
			 */
			sbicnextstate(dev, csr, asr);

			return 0;
		}

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

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

	/*
	 * Anyone at home?
	 */
	if (csr == SBIC_CSR_SEL_TIMEO) {
		dev->sc_xs->error = XS_SELTIMEOUT;
		QPRINTF(("Selection Timeout\n"));
		return 0;
	}

	QPRINTF(("Selection Complete\n"));

	/*
	 * Assume we're now selected
	 */
	GET_SBIC_selid(regs, id);
	dev->target    = id;
	dev->lun       = lun;
	dev->sc_flags |= SBICF_SELECTED;

	/*
	 * Enable (or not) reselection
	 * XXXSCW This is probably not necessary since we don't use use the
	 * Select-and-Xfer-with-ATN command to initiate a selection...
	 */
	if (!sbic_enable_reselect && dev->nexus_list.tqh_first == NULL)
		SET_SBIC_rselid (regs, 0);
	else
		SET_SBIC_rselid (regs, SBIC_RID_ER);

	/*
	 * We only really need to do anything when the target goes to MSG out
	 * If the device ignored ATN, it's probably old and brain-dead,
	 * but we'll try to support it anyhow.
	 * If it doesn't support message out, it definitely doesn't
	 * support synchronous transfers, so no point in even asking...
	 */
	if (csr == (SBIC_CSR_MIS_2 | MESG_OUT_PHASE)) {
		/*
		 * Send identify message (SCSI-2 requires an identify msg)
		 */
		if (sbic_inhibit_sync[id] &&
		    dev->sc_sync[id].state == SYNC_START) {
			/*
			 * Handle drives that don't want to be asked
			 * whether to go sync at all.
			 */
			dev->sc_sync[id].offset = 0;
			dev->sc_sync[id].period = sbic_min_period;
			dev->sc_sync[id].state  = SYNC_DONE;
		}

		/*
		 * Do we need to negotiate Synchronous Xfers for this target?
		 */
		if (dev->sc_sync[id].state != SYNC_START) {
			/*
			 * Nope, we've already negotiated.
			 * Now see if we should allow the target to
			 * disconnect/reselect...
			 */
			if (dev->sc_xs->xs_control & XS_CTL_POLL ||
			    dev->sc_flags & SBICF_ICMD ||
			    !sbic_enable_reselect)
				SEND_BYTE (regs, MSG_IDENTIFY | lun);
			else
				SEND_BYTE (regs, MSG_IDENTIFY_DR | lun);

		} else {
			/*
			 * try to initiate a sync transfer.
			 * So compose the sync message we're going
			 * to send to the target
			 */
#ifdef DEBUG
			if (sync_debug)
				printf("\nSending sync request "
				    "to target %d ... ", id);
#endif
			/*
			 * setup scsi message sync message request
			 */
			dev->sc_msg[0] = MSG_IDENTIFY | lun;
			dev->sc_msg[1] = MSG_EXT_MESSAGE;
			dev->sc_msg[2] = 3;
			dev->sc_msg[3] = MSG_SYNC_REQ;
			dev->sc_msg[4] = sbictoscsiperiod(dev, sbic_min_period);
			dev->sc_msg[5] = sbic_max_offset;

			sbicxfout(regs, 6, dev->sc_msg);

			dev->sc_sync[id].state = SYNC_SENT;
#ifdef DEBUG
			if (sync_debug)
				printf ("sent\n");
#endif
		}

		/*
		 * There's one interrupt still to come: the change to
		 * CMD phase...
		 */
		SBIC_WAIT(regs, SBIC_ASR_INT , 0);
		GET_SBIC_csr(regs, csr);
	}

	/*
	 * set sync or async
	 */
	if (dev->sc_sync[target].state == SYNC_DONE) {
#ifdef  DEBUG
        if (sync_debug)
		printf("select(%d): sync reg = 0x%02x\n", target,
		    SBIC_SYN(dev->sc_sync[target].offset,
		    dev->sc_sync[target].period));
#endif
		SET_SBIC_syn(regs, SBIC_SYN(dev->sc_sync[target].offset,
		    dev->sc_sync[target].period));
	} else {
#ifdef  DEBUG
		if (sync_debug)
			printf("select(%d): sync reg = 0x%02x\n", target,
			    SBIC_SYN(0,sbic_min_period));
#endif
		SET_SBIC_syn(regs, SBIC_SYN(0, sbic_min_period));
	}

	return csr;
}

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

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

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

	SBIC_TC_PUT (regs, 0);
	SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);
	SBIC_TC_PUT (regs, (unsigned)len);
	SET_SBIC_cmd (regs, SBIC_CMD_XFER_INFO);

	/*
	 * Loop for each byte transferred
	 */
	do {

		GET_SBIC_asr(regs, asr);

		if (asr & SBIC_ASR_DBR) {
			if (len) {
				SET_SBIC_data (regs, *buf);
				buf++;
				len--;
			} else {
				SET_SBIC_data (regs, 0);
			}
			wait = sbic_data_wait;
		}

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

#ifdef  DEBUG
	QPRINTF(("sbicxfout done: %d bytes remaining (wait:%d)\n", len, wait));
#endif

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

/*
 * Information Transfer *from* a Scsi Target
 * returns # bytes left to read
 */
int
sbicxfin(sbic_regmap_p regs, int len, void *bp)
{
	int wait = sbic_data_wait;
	u_char *buf = bp;
	u_char asr;
#ifdef  DEBUG
	u_char *obp = bp;
#endif

	WAIT_CIP(regs);

	SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);
	SBIC_TC_PUT(regs, (unsigned int)len);
	SET_SBIC_cmd (regs, SBIC_CMD_XFER_INFO);

	/*
	 * Loop for each byte transferred
	 */
	do {

		GET_SBIC_asr(regs, asr);

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

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

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

	SBIC_TC_PUT (regs, 0);

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

/*
 * SCSI 'immediate' command:  issue a command to some SCSI device
 * and get back an 'immediate' response (i.e., do programmed xfer
 * to get the response data).  'cbuf' is a buffer containing a scsi
 * command of length clen bytes.  'buf' is a buffer of length 'len'
 * bytes for data.  The transfer direction is determined by the device
 * (i.e., by the scsi bus data xfer phase).  If 'len' is zero, the
 * command must supply no data.
 *
 * Note that although this routine looks like it can handle disconnect/
 * reselect, the fact is that it can't. There is still some work to be
 * done to clean this lot up.
 */
int
sbicicmd(struct sbic_softc *dev, void *cbuf, int clen, void *buf, int len)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	struct sbic_acb *acb = dev->sc_nexus;
	u_char csr, asr;
	int still_busy = SBIC_STATE_RUNNING;

	/*
	 * Make sure pointers are OK
	 */
	dev->sc_last = dev->sc_cur = &acb->sc_pa;
	dev->sc_tcnt = acb->sc_tcnt = 0;

	acb->sc_dmacmd      = 0;
	acb->sc_pa.dc_count = 0; /* No DMA */
	acb->sc_kv.dc_addr  = buf;
	acb->sc_kv.dc_count = len;

#ifdef  DEBUG
	if (data_pointer_debug > 1)
		printf("sbicicmd(%d,%d):%d\n",
		    dev->target, dev->lun, acb->sc_kv.dc_count);
#endif

	/*
	 * set the sbic into non-DMA mode
	 */
	SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);

	dev->sc_stat[0] = 0xff;
	dev->sc_msg[0]  = 0xff;

	/*
	 * We're stealing the SCSI bus
	 */
	dev->sc_flags |= SBICF_ICMD;

	do {
		GET_SBIC_asr(regs, asr);

		/*
		 * select the SCSI bus (it's an error if bus isn't free)
		 */
		if ((dev->sc_flags & SBICF_SELECTED) == 0 &&
		    still_busy != SBIC_STATE_DISCONNECT) {
			if ((csr = sbicselectbus(dev)) == 0) {
				dev->sc_flags &= ~SBICF_ICMD;
				return -1;
			}
		} else if ((asr & (SBIC_ASR_BSY | SBIC_ASR_INT)) ==
		    SBIC_ASR_INT)
			GET_SBIC_csr(regs, csr);
		else
			csr = 0;

		if (csr) {

			QPRINTF((">ASR:0x%02x CSR:0x%02x< ", asr, csr));

			switch (csr) {

			case SBIC_CSR_S_XFERRED:
			case SBIC_CSR_DISC:
			case SBIC_CSR_DISC_1:
			    {
				u_char  phase;

				dev->sc_flags &= ~SBICF_SELECTED;
				GET_SBIC_cmd_phase(regs, phase);

				if (phase == 0x60) {
					GET_SBIC_tlun(regs, dev->sc_stat[0]);
					still_busy = SBIC_STATE_DONE; /* done */
				} else {
#ifdef DEBUG
					if (reselect_debug > 1)
						printf("sbicicmd: "
						    "handling disconnect\n");
#endif
					still_busy = SBIC_STATE_DISCONNECT;
				}
				break;
			    }

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

				if (sbicxfout(regs, clen, cbuf))
					still_busy = sbicabort(dev,
					    "icmd sending cmd");
		                break;

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

				/*
				 * The sbic does the status/cmd-complete
				 * reading ok, so do this with its
				 * hi-level commands.
				 */
#ifdef DEBUG
				if (sbic_debug)
					printf("SBICICMD status phase "
					    "(bsy=%d)\n", still_busy);
#endif
				SET_SBIC_cmd_phase(regs, 0x46);
				SET_SBIC_cmd(regs, SBIC_CMD_SEL_ATN_XFER);
				break;

			default:
				still_busy = sbicnextstate(dev, csr, asr);
				break;
			}

			/*
			 * make sure the last command was taken,
			 * ie. we're not hunting after an ignored command..
			 */
			GET_SBIC_asr(regs, asr);

			/*
			 * tapes may take a loooong time..
			 */
			while (asr & SBIC_ASR_BSY) {

				if (asr & SBIC_ASR_DBR) {
					int i;

					printf("sbicicmd: "
					    "Waiting while sbic is jammed, "
					    "CSR:%02x,ASR:%02x\n", csr, asr);
#ifdef DDB
					Debugger();
#endif
					/*
					 * SBIC is jammed
					 * DUNNO which direction
					 * Try old direction
					 */
					GET_SBIC_data(regs, i);
					GET_SBIC_asr(regs, asr);

					if (asr & SBIC_ASR_DBR)
						/* Wants us to write */
						SET_SBIC_data(regs, i);
				}

				GET_SBIC_asr(regs, asr);
			}
		}

		/*
		 * wait for last command to complete
		 */
		if (asr & SBIC_ASR_LCI) {
			printf("sbicicmd: last command ignored\n");
		} else if (still_busy >= SBIC_STATE_RUNNING) /* Bsy */
			SBIC_WAIT(regs, SBIC_ASR_INT, sbic_cmd_wait);

		/*
		 * do it again
		 */
	} while (still_busy >= SBIC_STATE_RUNNING && dev->sc_stat[0] == 0xff);

	/*
	 * Sometimes we need to do an extra read of the CSR
	 */
	GET_SBIC_csr(regs, csr);

#ifdef DEBUG
	if (data_pointer_debug > 1)
		printf("sbicicmd done(%d,%d):%d =%d=\n", dev->target, dev->lun,
		    acb->sc_kv.dc_count, dev->sc_stat[0]);
#endif

	dev->sc_flags &= ~SBICF_ICMD;

	return dev->sc_stat[0];
}

/*
 * Finish SCSI xfer command:  After the completion interrupt from
 * a read/write operation, sequence through the final phases in
 * programmed i/o.  This routine is a lot like sbicicmd except we
 * skip (and don't allow) the select, cmd out and data in/out phases.
 */
void
sbicxfdone(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_char phase, csr;
	int s;

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

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

	do {

		SBIC_WAIT(regs, SBIC_ASR_INT, 0);
		GET_SBIC_csr(regs, csr);
		QPRINTF(("%02x:", csr));

	} while ((csr != SBIC_CSR_DISC) && (csr != SBIC_CSR_DISC_1) &&
	    (csr != SBIC_CSR_S_XFERRED));

	dev->sc_flags &= ~SBICF_SELECTED;

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

	if (phase == 0x60)
		GET_SBIC_tlun(regs, dev->sc_stat[0]);
	else
		sbicerror(dev, csr);

	QPRINTF(("=STS:%02x=\n", dev->sc_stat[0]));

	splx(s);
}

/*
 * No DMA chains
 */
int
sbicgo(struct sbic_softc *dev, struct scsipi_xfer *xs)
{
	struct sbic_acb *acb = dev->sc_nexus;
	sbic_regmap_p regs = dev->sc_sbicp;
	int i, dmaflags, count, usedma;
	u_char csr, asr, *addr;

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

	usedma = sbicdmaok(dev, xs);

#ifdef DEBUG
	if (data_pointer_debug > 1)
		printf("sbicgo(%d,%d): usedma=%d\n",
		    dev->target, dev->lun, usedma);
#endif

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

	dev->sc_stat[0] = 0xff;

	/*
	 * Calculate DMA chains now
	 */
	if (acb->flags & ACB_DATAIN)
		dmaflags = DMAGO_READ;
	else
		dmaflags = 0;

	addr  = acb->sc_kv.dc_addr;
	count = acb->sc_kv.dc_count;

	if (count && ((char *)kvtop((void *)addr) != acb->sc_pa.dc_addr)) {
		printf("sbic: DMA buffer mapping changed %p->%x\n",
		    acb->sc_pa.dc_addr, kvtop((void *)addr));
#ifdef DDB
		Debugger();
#endif
	}

#ifdef DEBUG
	++sbicdma_ops;		/* count total DMA operations */
#endif

	/*
	 * Allocate the DMA chain
	 * Mark end of segment...
	 */
	acb->sc_tcnt        = dev->sc_tcnt = 0;
	acb->sc_pa.dc_count = 0;

	sbic_load_ptrs(dev);

	/*
	 * Enable interrupts but don't do any DMA
	 * enintr() also enables interrupts for the sbic
	 */
	dev->sc_enintr(dev);

	if (usedma) {
		dev->sc_tcnt = dev->sc_dmago(dev, acb->sc_pa.dc_addr,
		    acb->sc_pa.dc_count, dmaflags);
#ifdef DEBUG
		dev->sc_dmatimo = dev->sc_tcnt ? 1 : 0;
#endif
	} else
		dev->sc_dmacmd = 0; /* Don't use DMA */

	acb->sc_dmacmd = dev->sc_dmacmd;

#ifdef DEBUG
	if (data_pointer_debug > 1) {
		printf("sbicgo dmago:%d(%p:%lx) dmacmd=0x%02x\n", dev->target,
		    dev->sc_cur->dc_addr,
		    dev->sc_tcnt,
		    dev->sc_dmacmd);
	}
#endif

	/*
	 * Lets cycle a while then let the interrupt handler take over.
	 */
	GET_SBIC_asr(regs, asr);

	do {

		QPRINTF(("go "));

		/*
		 * Handle the new phase
		 */
		i = sbicnextstate(dev, csr, asr);
#if 0
		WAIT_CIP(regs);
#endif
		if (i == SBIC_STATE_RUNNING) {
			GET_SBIC_asr(regs, asr);

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

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

	} while (i == SBIC_STATE_RUNNING && asr & (SBIC_ASR_INT|SBIC_ASR_LCI));

	if (i == SBIC_STATE_DONE) {
		if (dev->sc_stat[0] == 0xff)
#if 0
			printf("sbicgo: done & stat = 0xff\n");
#else
			;
#endif
		else
			return 1;	/* Did we really finish that fast? */
	}

	return 0;
}


int
sbicintr(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_char asr, csr;
	int i;

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

	GET_SBIC_csr(regs, csr);

	do {

		QPRINTF(("intr[0x%x]", csr));

		i = sbicnextstate(dev, csr, asr);
#if 0
		WAIT_CIP(regs);
#endif
		if (i == SBIC_STATE_RUNNING) {
			GET_SBIC_asr(regs, asr);

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

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

	} while (i == SBIC_STATE_RUNNING && asr & (SBIC_ASR_INT|SBIC_ASR_LCI));

	QPRINTF(("intr done. state=%d, asr=0x%02x\n", i, asr));

	return 1;
}

/*
 * Run commands and wait for disconnect.
 * This is only ever called when a command is in progress, when we
 * want to busy wait for it to finish.
 */
int
sbicpoll(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	u_char asr, csr = SBIC_CSR_RESET;	/* XXX: Quell un-init warning */
	int i;

	/*
	 * Wait for the next interrupt
	 */
	SBIC_WAIT(regs, SBIC_ASR_INT, sbic_cmd_wait);

	do {
		GET_SBIC_asr (regs, asr);

		if (asr & SBIC_ASR_INT)
			GET_SBIC_csr(regs, csr);

		QPRINTF(("poll[0x%x]", csr));

		/*
		 * Handle it
		 */
		i = sbicnextstate(dev, csr, asr);

		WAIT_CIP(regs);
		GET_SBIC_asr(regs, asr);

		/*
		 * tapes may take a loooong time..
		 */
		while (asr & SBIC_ASR_BSY) {
			u_char z = 0;

			if (asr & SBIC_ASR_DBR) {
				printf("sbipoll: Waiting while sbic is jammed,"
			    " CSR:%02x,ASR:%02x\n", csr, asr);
#ifdef DDB
				Debugger();
#endif
				/*
				 * SBIC is jammed
				 * DUNNO which direction
				 * Try old direction
				 */
				GET_SBIC_data(regs, z);
				GET_SBIC_asr(regs, asr);

				if (asr & SBIC_ASR_DBR) /* Wants us to write */
					SET_SBIC_data(regs, z);
			}

			GET_SBIC_asr(regs, asr);
		}

		if (asr & SBIC_ASR_LCI)
			printf("sbicpoll: LCI asr:%02x csr:%02x\n", asr,csr);
		else if (i == SBIC_STATE_RUNNING) /* BSY */
			SBIC_WAIT(regs, SBIC_ASR_INT, sbic_cmd_wait);

	} while (i == SBIC_STATE_RUNNING);

	return 1;
}

/*
 * Handle a single msgin
 */
int
sbicmsgin(struct sbic_softc *dev)
{
	sbic_regmap_p regs = dev->sc_sbicp;
	int recvlen = 1;
	u_char asr, csr, *tmpaddr, *msgaddr;

	tmpaddr = msgaddr = dev->sc_msg;

	tmpaddr[0] = 0xff;
	tmpaddr[1] = 0xff;

	GET_SBIC_asr(regs, asr);

#ifdef DEBUG
	if (reselect_debug > 1)
		printf("sbicmsgin asr=%02x\n", asr);
#endif

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

	SBIC_TC_PUT(regs, 0);
	SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);

	do {
		while (recvlen--) {

			/*
			 * Fetch the next byte of the message
			 */
			RECV_BYTE(regs, *tmpaddr);

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

#ifdef DEBUG
			if (reselect_debug > 1)
				printf("sbicmsgin: got %02x csr %02x\n",
				    *tmpaddr, csr);
#endif

			tmpaddr++;

			if (recvlen) {
				/*
				 * Clear ACK, and wait for the interrupt
				 * for the next byte
				 */
				SET_SBIC_cmd(regs, SBIC_CMD_CLR_ACK);
				SBIC_WAIT(regs, SBIC_ASR_INT, 0);
				GET_SBIC_csr(regs, csr);
			}
		}

		if (msgaddr[0] == 0xff) {
			printf("sbicmsgin: sbic swallowed our message\n");
			break;
		}

#ifdef DEBUG
		if (sync_debug) {
			GET_SBIC_asr(regs, asr);
			printf("msgin done csr 0x%x asr 0x%x msg 0x%x\n",
			    csr, asr, msgaddr[0]);
		}
#endif
		/*
		 * test whether this is a reply to our sync
		 * request
		 */
		if (MSG_ISIDENTIFY(msgaddr[0])) {

			/*
			 * Got IFFY msg -- ack it
			 */
			QPRINTF(("IFFY"));

		} else if (msgaddr[0] == MSG_REJECT &&
		    dev->sc_sync[dev->target].state == SYNC_SENT) {

			/*
			 * Target probably rejected our Sync negotiation.
			 */
			QPRINTF(("REJECT of SYN"));

#ifdef DEBUG
			if (sync_debug)
				printf("target %d rejected sync, going async\n",
				    dev->target);
#endif

			dev->sc_sync[dev->target].period = sbic_min_period;
			dev->sc_sync[dev->target].offset = 0;
			dev->sc_sync[dev->target].state  = SYNC_DONE;
			SET_SBIC_syn(regs,
			    SBIC_SYN(dev->sc_sync[dev->target].offset,
			    dev->sc_sync[dev->target].period));

		} else if (msgaddr[0] == MSG_REJECT) {

			/*
			 * we'll never REJECt a REJECT message..
			 */
			QPRINTF(("REJECT"));

		} else if (msgaddr[0] == MSG_SAVE_DATA_PTR) {

			/*
			 * don't reject this either.
			 */
			QPRINTF(("MSG_SAVE_DATA_PTR"));

		} else if (msgaddr[0] == MSG_RESTORE_PTR) {

			/*
			 * don't reject this either.
			 */
			QPRINTF(("MSG_RESTORE_PTR"));

		} else if (msgaddr[0] == MSG_DISCONNECT) {

			/*
			 * Target is disconnecting...
			 */
			QPRINTF(("DISCONNECT"));

#ifdef DEBUG
			if (reselect_debug > 1 && msgaddr[0] == MSG_DISCONNECT)
				printf("sbicmsgin: got disconnect msg %s\n",
				    (dev->sc_flags & SBICF_ICMD) ?
				    "rejecting" : "");
#endif

			if (dev->sc_flags & SBICF_ICMD) {
				/*
				 * We're in immediate mode. Prevent disconnects.
				 * prepare to reject the message, NACK
				 */
				SET_SBIC_cmd(regs, SBIC_CMD_SET_ATN);
				WAIT_CIP(regs);
			}

		} else if (msgaddr[0] == MSG_CMD_COMPLETE) {

			/*
			 * !! KLUDGE ALERT !! quite a few drives don't seem to
			 * really like the current way of sending the
			 * sync-handshake together with the ident-message, and
			 * they react by sending command-complete and
			 * disconnecting right after returning the valid sync
			 * handshake. So, all I can do is reselect the drive,
			 * and hope it won't disconnect again. I don't think
			 * this is valid behavior, but I can't help fixing a
			 * problem that apparently exists.
			 *
			 * Note: we should not get here on `normal' command
			 * completion, as that condition is handled by the
			 * high-level sel&xfer resume command used to walk
			 * thru status/cc-phase.
			 */
			QPRINTF(("CMD_COMPLETE"));

#ifdef DEBUG
			if (sync_debug)
				printf("GOT MSG %d! target %d acting weird.."
				    " waiting for disconnect...\n",
				    msgaddr[0], dev->target);
#endif

			/*
			 * Check to see if sbic is handling this
			 */
			GET_SBIC_asr(regs, asr);

			/*
			 * XXXSCW: I'm not convinced of this,
			 * we haven't negated ACK yet...
			 */
			if (asr & SBIC_ASR_BSY)
				return SBIC_STATE_RUNNING;

			/*
			 * Let's try this: Assume it works and set status to 00
			 */
			dev->sc_stat[0] = 0;

		} else if (msgaddr[0] == MSG_EXT_MESSAGE &&
		    tmpaddr == &(msgaddr[1])) {

			/*
			 * Target is sending us an extended message.
			 * We'll assume it's the response to our Sync.
			 * negotiation.
			 */
			QPRINTF(("ExtMSG\n"));

			/*
			 * Read in whole extended message.
			 * First, negate ACK to accept
			 * the MSG_EXT_MESSAGE byte...
			 */
			SET_SBIC_cmd(regs, SBIC_CMD_CLR_ACK);

			/*
			 * Wait for the interrupt for the next byte (length)
			 */
			SBIC_WAIT(regs, SBIC_ASR_INT, 0);
			GET_SBIC_csr(regs, csr);

#ifdef  DEBUG
			QPRINTF(("CLR ACK csr %02x\n", csr));
#endif

			/*
			 * Read the length byte
			 */
			RECV_BYTE(regs, *tmpaddr);

			/*
			 * Wait for command completion IRQ
			 */
			SBIC_WAIT(regs, SBIC_ASR_INT, 0);
			GET_SBIC_csr(regs, csr);

			/*
			 * Reload the loop counter
			 */
			recvlen = *tmpaddr++;

			QPRINTF(("Recving ext msg, csr %02x len %02x\n",
			    csr, recvlen));

		} else if (msgaddr[0] == MSG_EXT_MESSAGE &&
		    msgaddr[1] == 3 &&
		    msgaddr[2] == MSG_SYNC_REQ ) {

			/*
			 * We've received the complete Extended Message Sync.
			 * Request...
			 */
			QPRINTF(("SYN"));

			/*
			 * Compute the required Transfer Period for
			 * the WD chip...
			 */
			dev->sc_sync[dev->target].period =
			    sbicfromscsiperiod(dev, msgaddr[3]);
			dev->sc_sync[dev->target].offset = msgaddr[4];
			dev->sc_sync[dev->target].state  = SYNC_DONE;

			/*
			 * Put the WD chip in synchronous mode
			 */
			SET_SBIC_syn(regs,
			    SBIC_SYN(dev->sc_sync[dev->target].offset,
                            dev->sc_sync[dev->target].period));
#ifdef  DEBUG
			if (sync_debug)
				printf("msgin(%d): sync reg = 0x%02x\n",
				    dev->target,
				    SBIC_SYN(dev->sc_sync[dev->target].offset,
				    dev->sc_sync[dev->target].period));
#endif

			printf("%s: target %d now synchronous, "
			    "period=%dns, offset=%d.\n",
			    device_xname(dev->sc_dev), dev->target,
			    msgaddr[3] * 4, msgaddr[4]);

		} else {

			/*
			 * We don't support whatever this message is...
			 */
#ifdef DEBUG
			if (sbic_debug || sync_debug)
				printf("sbicmsgin: Rejecting message 0x%02x\n",
				    msgaddr[0]);
#endif

			/*
			 * prepare to reject the message, NACK
			 */
			SET_SBIC_cmd(regs, SBIC_CMD_SET_ATN);
			WAIT_CIP(regs);
		}

		/*
		 * Negate ACK to complete the transfer
		 */
		SET_SBIC_cmd(regs, SBIC_CMD_CLR_ACK);

		/*
		 * Wait for the interrupt for the next byte, or phase change.
		 * Only read the CSR if we have more data to transfer.
		 * XXXSCW: We should really verify that we're still in
		 * MSG IN phase before blindly going back around this loop,
		 * but that would mean we read the CSR... <sigh>
		 */
		SBIC_WAIT(regs, SBIC_ASR_INT, 0);
		if (recvlen > 0)
			GET_SBIC_csr(regs, csr);

	} while (recvlen > 0);

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


/*
 * sbicnextstate()
 * return:
 *      SBIC_STATE_DONE        == done
 *      SBIC_STATE_RUNNING     == working
 *      SBIC_STATE_DISCONNECT  == disconnected
 *      SBIC_STATE_ERROR       == error
 */
int
sbicnextstate(struct sbic_softc *dev, u_char csr, u_char asr)
{
	sbic_regmap_p   regs = dev->sc_sbicp;
	struct sbic_acb *acb = dev->sc_nexus;

	QPRINTF(("next[%02x,%02x]: ",asr,csr));

	switch (csr) {

	case SBIC_CSR_XFERRED | CMD_PHASE:
	case SBIC_CSR_MIS     | CMD_PHASE:
	case SBIC_CSR_MIS_1   | CMD_PHASE:
	case SBIC_CSR_MIS_2   | CMD_PHASE:
		if ( sbicxfout(regs, acb->clen, &acb->cmd) )
                goto abort;
		break;

	case SBIC_CSR_XFERRED | STATUS_PHASE:
	case SBIC_CSR_MIS     | STATUS_PHASE:
	case SBIC_CSR_MIS_1   | STATUS_PHASE:
	case SBIC_CSR_MIS_2   | STATUS_PHASE:
		SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);

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

#ifdef DEBUG
		dev->sc_dmatimo = 0;
		if (data_pointer_debug > 1)
			printf("next dmastop: %d(%p:%lx)\n",
			    dev->target,
			    dev->sc_cur->dc_addr,
			    dev->sc_tcnt);
#endif
		/*
		 * Stop the DMA chip
		 */
		dev->sc_dmastop(dev);

		dev->sc_flags &= ~(SBICF_INDMA | SBICF_DCFLUSH);

		/*
		 * Indicate to the upper layers that the command is done
		 */
		sbic_scsidone(acb, dev->sc_stat[0]);

		return SBIC_STATE_DONE;

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

		/*
		 * Should we transfer using PIO or DMA ?
		 */
		if (dev->sc_xs->xs_control & XS_CTL_POLL ||
		    dev->sc_flags & SBICF_ICMD ||
		    acb->sc_dmacmd == 0 ) {

			/*
			 * Do PIO transfer
			 */
			int i;

#ifdef DEBUG
			if (data_pointer_debug > 1)
				printf("next PIO: %d(%p:%x)\n", dev->target,
				    acb->sc_kv.dc_addr,
				    acb->sc_kv.dc_count);
#endif

			if (SBIC_PHASE(csr) == DATA_IN_PHASE)
				/*
				 * data in
				 */
				i = sbicxfin(regs, acb->sc_kv.dc_count,
				    acb->sc_kv.dc_addr);
			else
				/*
				 * data out
				 */
				i = sbicxfout(regs, acb->sc_kv.dc_count,
				    acb->sc_kv.dc_addr);

			acb->sc_kv.dc_addr += (acb->sc_kv.dc_count - i);
			acb->sc_kv.dc_count = i;

			/*
			 * Update current count...
			 */
			acb->sc_tcnt = dev->sc_tcnt = i;

			dev->sc_flags &= ~SBICF_INDMA;

		} else {

			/*
			 * Do DMA transfer
			 * set next DMA addr and dec count
			 */
			sbic_save_ptrs(dev);
			sbic_load_ptrs(dev);

			SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI |
			    SBIC_MACHINE_DMA_MODE);

#ifdef DEBUG
			dev->sc_dmatimo = 1;
			if (data_pointer_debug > 1)
				printf("next DMA: %d(%p:%lx)\n", dev->target,
				    dev->sc_cur->dc_addr,
				    dev->sc_tcnt);
#endif
			/*
			 * Start the DMA chip going
			 */
			dev->sc_tcnt = dev->sc_dmanext(dev);

			/*
			 * Tell the WD chip how much to transfer
			 * this time around
			 */
			SBIC_TC_PUT(regs, (unsigned)dev->sc_tcnt);

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

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

	case SBIC_CSR_XFERRED | MESG_IN_PHASE:
	case SBIC_CSR_MIS     | MESG_IN_PHASE:
	case SBIC_CSR_MIS_1   | MESG_IN_PHASE:
	case SBIC_CSR_MIS_2   | MESG_IN_PHASE:
		sbic_save_ptrs(dev);

		/*
		 * Handle a single message in...
		 */
		return sbicmsgin(dev);

	case SBIC_CSR_MSGIN_W_ACK:
		/*
		 * We should never see this since it's handled in 'sbicmsgin()'
		 * but just for the sake of paranoia...
		 */
		/* Dunno what I'm ACKing */
		SET_SBIC_cmd(regs, SBIC_CMD_CLR_ACK);
		printf("Acking unknown msgin CSR:%02x",csr);
        	break;

	case SBIC_CSR_XFERRED | MESG_OUT_PHASE:
	case SBIC_CSR_MIS     | MESG_OUT_PHASE:
	case SBIC_CSR_MIS_1   | MESG_OUT_PHASE:
	case SBIC_CSR_MIS_2   | MESG_OUT_PHASE:
		/*
		 * We only ever handle a message out phase here for sending a
		 * REJECT message.
		 */
		sbic_save_ptrs(dev);

#ifdef DEBUG
		if (sync_debug)
			printf("sending REJECT msg to last msg.\n");
#endif

		SEND_BYTE(regs, MSG_REJECT);
		WAIT_CIP(regs);
		break;

	case SBIC_CSR_DISC:
	case SBIC_CSR_DISC_1:
		/*
		 * Try to schedule another target
		 */
		sbic_save_ptrs(dev);

		dev->sc_flags &= ~SBICF_SELECTED;

#ifdef DEBUG
		if (reselect_debug > 1)
			printf("sbicnext target %d disconnected\n",
			    dev->target);
#endif

		TAILQ_INSERT_HEAD(&dev->nexus_list, acb, chain);

		++dev->sc_tinfo[dev->target].dconns;

		dev->sc_nexus = NULL;
		dev->sc_xs    = NULL;

		if (acb->xs->xs_control & XS_CTL_POLL ||
		    dev->sc_flags & SBICF_ICMD ||
		    !sbic_parallel_operations )
			return SBIC_STATE_DISCONNECT;

		QPRINTF(("sbicnext: calling sbic_sched\n"));

		sbic_sched(dev);

		QPRINTF(("sbicnext: sbic_sched returned\n"));

		return SBIC_STATE_DISCONNECT;

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

		GET_SBIC_rselid(regs, newtarget);

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

		if (csr == SBIC_CSR_RSLT_IFY) {

			/*
			 * Read Identify msg to avoid lockup
			 */
			GET_SBIC_data(regs, newlun);
			WAIT_CIP(regs);
			newlun &= SBIC_TLUN_MASK;

		} else {

			/*
			 * Need to read Identify message the hard way, assuming
			 * the target even sends us one...
			 */
			for (newlun = 255; newlun; --newlun) {
				GET_SBIC_asr(regs, asr);
				if (asr & SBIC_ASR_INT)
					break;
				delay(10);
			}

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

				if (csr == (SBIC_CSR_MIS   | MESG_IN_PHASE) ||
				    csr == (SBIC_CSR_MIS_1 | MESG_IN_PHASE) ||
				    csr == (SBIC_CSR_MIS_2 | MESG_IN_PHASE)) {
					/*
					 * Yup, gone to message in.
					 * Fetch the target LUN
					 */
					sbicmsgin(dev);
					newlun = dev->sc_msg[0] & 0x07;

				} else {
					/*
					 * Whoops! Target didn't go to
					 * message in phase!!
					 */
					printf("RSLT_NI - "
					    "not MESG_IN_PHASE %x\n", csr);
					newlun = 0;	/* XXXSCW */
				}
			}
		}

		/*
		 * Ok, we have the identity of the reselecting target.
		 */
#ifdef DEBUG
		if (reselect_debug > 1 ||
		    (reselect_debug && csr == SBIC_CSR_RSLT_NI)) {
			printf("sbicnext: reselect %s from targ %d lun %d\n",
			    csr == SBIC_CSR_RSLT_NI ? "NI" : "IFY",
			    newtarget, newlun);
		}
#endif

		if (dev->sc_nexus) {
			/*
			 * Whoops! We've been reselected with
			 * a command in progress!
			 * The best we can do is to put the current command
			 * back on the ready list and hope for the best.
			 */
#ifdef DEBUG
			if (reselect_debug > 1) {
				printf("%s: reselect %s with active command\n",
				    device_xname(dev->sc_dev),
				csr == SBIC_CSR_RSLT_NI ? "NI" : "IFY");
			}
#endif

			TAILQ_INSERT_HEAD(&dev->ready_list, dev->sc_nexus,
			    chain);

			dev->sc_tinfo[dev->target].lubusy &= ~(1 << dev->lun);

			dev->sc_nexus = NULL;
			dev->sc_xs    = NULL;
		}

		/*
		 * Reload sync values for this target
		 */
		if (dev->sc_sync[newtarget].state == SYNC_DONE)
			SET_SBIC_syn(regs,
			    SBIC_SYN(dev->sc_sync[newtarget].offset,
			    dev->sc_sync[newtarget].period));
		else
			SET_SBIC_syn(regs, SBIC_SYN (0, sbic_min_period));

		/*
		 * Loop through the nexus list until we find the saved entry
		 * for the reselecting target...
		 */
		for (acb = dev->nexus_list.tqh_first; acb;
                     acb = acb->chain.tqe_next) {

			if ( acb->xs->xs_periph->periph_target == newtarget &&
			     acb->xs->xs_periph->periph_lun    == newlun) {
				/*
				 * We've found the saved entry. Dequeue it, and
				 * make it current again.
				 */
				TAILQ_REMOVE(&dev->nexus_list, acb, chain);

				dev->sc_nexus  = acb;
				dev->sc_xs     = acb->xs;
				dev->sc_flags |= SBICF_SELECTED;
				dev->target    = newtarget;
				dev->lun       = newlun;
				break;
			}
		}

		if (acb == NULL) {
			printf("%s: reselect %s targ %d not in nexus_list %p\n",
			    device_xname(dev->sc_dev),
			    csr == SBIC_CSR_RSLT_NI ? "NI" : "IFY", newtarget,
			    &dev->nexus_list.tqh_first);
			panic("bad reselect in sbic");
		}

		if (csr == SBIC_CSR_RSLT_IFY)
			SET_SBIC_cmd(regs, SBIC_CMD_CLR_ACK);
	        break;
	    }
	default:
        abort:
		/*
		 * Something unexpected happened -- deal with it.
		 */
		printf("next: aborting asr 0x%02x csr 0x%02x\n", asr, csr);

#ifdef DDB
		Debugger();
#endif

#ifdef DEBUG
		dev->sc_dmatimo = 0;
		if (data_pointer_debug > 1)
			printf("next dmastop: %d(%p:%lx)\n", dev->target,
			    dev->sc_cur->dc_addr,
			    dev->sc_tcnt);
#endif

		dev->sc_dmastop(dev);
		SET_SBIC_control(regs, SBIC_CTL_EDI | SBIC_CTL_IDI);
		if (dev->sc_xs)
			sbicerror(dev, csr);
		sbicabort(dev, "next");

		if (dev->sc_flags & SBICF_INDMA) {
			dev->sc_flags &= ~(SBICF_INDMA | SBICF_DCFLUSH);

#ifdef DEBUG
			dev->sc_dmatimo = 0;
			if (data_pointer_debug > 1)
				printf("next dmastop: %d(%p:%lx)\n",
				    dev->target,
				    dev->sc_cur->dc_addr,
				    dev->sc_tcnt);
#endif
			sbic_scsidone(acb, -1);
		}

		return SBIC_STATE_ERROR;
	}

	return SBIC_STATE_RUNNING;
}


/*
 * Check if DMA can not be used with specified buffer
 */
int
sbiccheckdmap(void *bp, u_long len, u_long mask)
{
	u_char  *buffer;
	u_long  phy_buf;
	u_long  phy_len;

	buffer = bp;

	if (len == 0)
		return 1;

	while (len) {

		phy_buf = kvtop((void *)buffer);
		phy_len = PAGE_SIZE - ((int)buffer & PGOFSET);

		if (len < phy_len)
			phy_len = len;

		if (phy_buf & mask)
			return 1;

		buffer += phy_len;
		len    -= phy_len;
	}

	return 0;
}

int
sbictoscsiperiod(struct sbic_softc *dev, int a)
{
	unsigned int fs;

	/*
	 * cycle = DIV / (2 * CLK)
	 * DIV = FS + 2
	 * best we can do is 200ns at 20 MHz, 2 cycles
	 */

	GET_SBIC_myid(dev->sc_sbicp, fs);

	fs = (fs >> 6) + 2;	/* DIV */

	fs = (fs * 10000) / (dev->sc_clkfreq << 1);	/* Cycle, in ns */

	if (a < 2)
		a = 8;		/* map to Cycles */

	return (fs * a) >> 2;	/* in 4 ns units */
}

int
sbicfromscsiperiod(struct sbic_softc *dev, int p)
{
	unsigned int fs, ret;

	/*
	 * Just the inverse of the above
	 */
	GET_SBIC_myid(dev->sc_sbicp, fs);

	fs = (fs >> 6) + 2;	/* DIV */

	fs = (fs * 10000) / (dev->sc_clkfreq << 1);	/* Cycle, in ns */

	ret = p << 2;		/* in ns units */
	ret = ret / fs;		/* in Cycles */

	if (ret < sbic_min_period)
		return(sbic_min_period);

	/*
	 * verify rounding
	 */
	if (sbictoscsiperiod(dev, ret) < p)
		ret++;

	return (ret >= 8) ? 0 : ret;
}

#ifdef DEBUG
void
sbictimeout(struct sbic_softc *dev)
{
	int s, asr;

	s = splbio();

	if (dev->sc_dmatimo) {

		if (dev->sc_dmatimo > 1) {

			printf("%s: DMA timeout #%d\n", device_xname(dev->sc_dev),
                            dev->sc_dmatimo - 1);

			GET_SBIC_asr(dev->sc_sbicp, asr);

			if (asr & SBIC_ASR_INT) {
				/*
				 * We need to service a missed IRQ
				 */
				sbicintr(dev);
			} else {
				(void)sbicabort(dev, "timeout");
				splx(s);
				return;
			}
		}

		dev->sc_dmatimo++;
	}

	splx(s);

	callout_reset(&dev->sc_timo_ch, 30 * hz, (void *)sbictimeout, dev);
}
#endif