xref: /src/sys/arch/atari/dev/ncr5380.c

/*	$NetBSD: ncr5380.c,v 1.69 2011/06/05 06:33:42 tsutsui Exp $	*/

/*
 * Copyright (c) 1995 Leo Weppelman.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ncr5380.c,v 1.69 2011/06/05 06:33:42 tsutsui Exp $");

/*
 * Bit mask of targets you want debugging to be shown
 */
uint8_t dbg_target_mask = 0x7f;

/*
 * Set bit for target when parity checking must be disabled.
 * My (LWP) Maxtor 7245S  seems to generate parity errors on about 50%
 * of all transfers while the data is correct!?
 */
uint8_t ncr5380_no_parchk = 0xff;

#ifdef	AUTO_SENSE

/*
 * Bit masks of targets that accept linked commands, and those
 * that we've already checked out.  Some devices will report
 * that they support linked commands when they have problems with
 * them.  By default, don't try them on any devices.  Allow an
 * option to override.
 */
#ifdef	TRY_SCSI_LINKED_COMMANDS
uint8_t ncr_test_link = ((~TRY_SCSI_LINKED_COMMANDS) & 0x7f);
#else
uint8_t ncr_test_link = 0x7f;
#endif
uint8_t ncr_will_link = 0x00;

#endif	/* AUTO_SENSE */

/*
 * This is the default sense-command we send.
 */
static uint8_t sense_cmd[] = {
	SCSI_REQUEST_SENSE, 0, 0, 0, sizeof(struct scsi_sense_data), 0
};

/*
 * True if the main co-routine is running
 */
static volatile int	main_running = 0;

/*
 * Mask of targets selected
 */
static uint8_t	busy;

static void	ncr5380_minphys(struct buf *bp);
static void	ncr5380_scsi_request(struct scsipi_channel *,
		    scsipi_adapter_req_t, void *);
static void	ncr5380_show_scsi_cmd(struct scsipi_xfer *xs);

static SC_REQ	req_queue[NREQ];
static SC_REQ	*free_head = NULL;	/* Free request structures	*/


/*
 * Inline functions:
 */

/*
 * Wait for request-line to become active. When it doesn't return 0.
 * Otherwise return != 0.
 * The timeouts in the 'wait_req_*' functions are arbitrary and rather
 * large. In 99% of the invocations nearly no timeout is needed but in
 * some cases (especially when using my tapedrive, a Tandberg 3600) the
 * device is busy internally and the first SCSI-phase will be delayed.
 */
static inline int
wait_req_true(void)
{
	int timeout = 250000;

	while ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_REQ) == 0 && --timeout)
		delay(1);
	return GET_5380_REG(NCR5380_IDSTAT) & SC_S_REQ;
}

/*
 * Wait for request-line to become inactive. When it doesn't return 0.
 * Otherwise return != 0.
 */
static inline int
wait_req_false(void)
{
	int timeout = 250000;

	while ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_REQ) && --timeout)
		delay(1);
	return (GET_5380_REG(NCR5380_IDSTAT) & SC_S_REQ) == 0;
}

static inline void
ack_message(void)
{

	SET_5380_REG(NCR5380_ICOM, 0);
}

static inline void
nack_message(SC_REQ *reqp, u_char msg)
{

	SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
	reqp->msgout = msg;
}

static inline void
finish_req(SC_REQ *reqp)
{
	int			sps;
	struct scsipi_xfer	*xs = reqp->xs;

#ifdef REAL_DMA
	/*
	 * If we bounced, free the bounce buffer
	 */
	if (reqp->dr_flag & DRIVER_BOUNCING)
		free_bounceb(reqp->bounceb);
#endif /* REAL_DMA */
#ifdef DBG_REQ
	if (dbg_target_mask & (1 << reqp->targ_id))
		show_request(reqp, "DONE");
#endif
#ifdef DBG_ERR_RET
	if ((dbg_target_mask & (1 << reqp->targ_id)) && (reqp->xs->error != 0))
		show_request(reqp, "ERR_RET");
#endif
	/*
	 * Return request to free-q
	 */
	sps = splbio();
	reqp->next = free_head;
	free_head  = reqp;
	splx(sps);

	if ((reqp->dr_flag & DRIVER_LINKCHK) == 0)
		scsipi_done(xs);
}

/*
 * Auto config stuff....
 */
void	ncr_attach(struct device *, struct device *, void *);
int	ncr_match(struct device *, struct cfdata *, void *);

/*
 * Tricks to make driver-name configurable
 */
#define CFNAME(n)	__CONCAT(n,_cd)
#define CANAME(n)	__CONCAT(n,_ca)
#define CFSTRING(n)	__STRING(n)
#define	CFDRNAME(n)	n

CFATTACH_DECL_NEW(CFDRNAME(DRNAME), sizeof(struct ncr_softc),
    ncr_match, ncr_attach, NULL, NULL);

extern struct cfdriver CFNAME(DRNAME);

int
ncr_match(device_t parent, cfdata_t cf, void *aux)
{

	return machine_match(parent, cf, aux, &CFNAME(DRNAME));
}

void
ncr_attach(device_t parent, device_t self, void *aux)
{
	struct ncr_softc	*sc;
	int			i;

	sc = device_private(self);
	sc->sc_dev = self;

	sc->sc_adapter.adapt_dev = self;
	sc->sc_adapter.adapt_openings = 7;
	sc->sc_adapter.adapt_max_periph = 1;
	sc->sc_adapter.adapt_ioctl = NULL;
	sc->sc_adapter.adapt_minphys = ncr5380_minphys;
	sc->sc_adapter.adapt_request = ncr5380_scsi_request;

	sc->sc_channel.chan_adapter = &sc->sc_adapter;
	sc->sc_channel.chan_bustype = &scsi_bustype;
	sc->sc_channel.chan_channel = 0;
	sc->sc_channel.chan_ntargets = 8;
	sc->sc_channel.chan_nluns = 8;
	sc->sc_channel.chan_id = 7;

	/*
	 * bitmasks
	 */
	sc->sc_noselatn = 0;
	sc->sc_selected = 0;

	/*
	 * Initialize machine-type specific things...
	 */
	scsi_mach_init(sc);
	printf("\n");

	/*
	 * Initialize request queue freelist.
	 */
	for (i = 0; i < NREQ; i++) {
		req_queue[i].next = free_head;
		free_head = &req_queue[i];
	}

	/*
	 * Initialize the host adapter
	 */
	scsi_idisable();
	ENABLE_NCR5380(sc);
	SET_5380_REG(NCR5380_ICOM, 0);
	SET_5380_REG(NCR5380_MODE, IMODE_BASE);
	SET_5380_REG(NCR5380_TCOM, 0);
	SET_5380_REG(NCR5380_IDSTAT, 0);
	scsi_ienable();

	/*
	 * attach all scsi units on us
	 */
	config_found(self, &sc->sc_channel, scsiprint);
}

/*
 * End of auto config stuff....
 */

/*
 * Carry out a request from the high level driver.
 */
static void
ncr5380_scsi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
    void *arg)
{
	struct scsipi_xfer *xs;
	struct scsipi_periph *periph;
	struct ncr_softc *sc;
	int	sps;
	SC_REQ	*reqp, *link, *tmp;
	int	flags;

	sc = device_private(chan->chan_adapter->adapt_dev);

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

		/*
		 * We do not queue RESET commands
		 */
		flags = xs->xs_control;
		if (flags & XS_CTL_RESET) {
			scsi_reset_verbose(sc, "Got reset-command");
			scsipi_done(xs);
			return;
		}

		/*
		 * Get a request block
		 */
		sps = splbio();
		if ((reqp = free_head) == 0) {
			xs->error = XS_RESOURCE_SHORTAGE;
			scsipi_done(xs);
			splx(sps);
			return;
		}
		free_head  = reqp->next;
		reqp->next = NULL;
		splx(sps);

		/*
		 * Initialize our private fields
		 */
		reqp->dr_flag   = (flags & XS_CTL_POLL) ? DRIVER_NOINT : 0;
		reqp->phase     = NR_PHASE;
		reqp->msgout    = MSG_NOOP;
		reqp->status    = SCSGOOD;
		reqp->message   = 0xff;
		reqp->link      = NULL;
		reqp->xs        = xs;
		reqp->targ_id   = xs->xs_periph->periph_target;
		reqp->targ_lun  = xs->xs_periph->periph_lun;
		reqp->xdata_ptr = (u_char*)xs->data;
		reqp->xdata_len = xs->datalen;
		memcpy(&reqp->xcmd, xs->cmd, xs->cmdlen);
		reqp->xcmd_len = xs->cmdlen;
		reqp->xcmd.bytes[0] |= reqp->targ_lun << 5;

#ifdef REAL_DMA
		/*
		 * Check if DMA can be used on this request
		 */
		if (scsi_dmaok(reqp))
			reqp->dr_flag |= DRIVER_DMAOK;
#endif /* REAL_DMA */

		/*
		 * Insert the command into the issue queue. Note that
		 * 'REQUEST SENSE' commands are inserted at the head of the
		 * queue since any command will clear the existing contingent
		 * allegience condition and the sense data is only valid while
		 * the condition exists. When possible, link the command to a
		 * previous command to the same target. This is not very
		 * sensible when AUTO_SENSE is not defined! Interrupts are
		 * disabled while we are fiddling with the issue-queue.
		 */
		sps = splbio();
		link = NULL;
		if ((issue_q == NULL) ||
		    (reqp->xcmd.opcode == SCSI_REQUEST_SENSE)) {
			reqp->next = issue_q;
			issue_q    = reqp;
		} else {
			tmp  = issue_q;
			do {
				if (!link && (tmp->targ_id == reqp->targ_id) &&
				    !tmp->link)
					link = tmp;
			} while (tmp->next && (tmp = tmp->next));
			tmp->next = reqp;
#ifdef AUTO_SENSE
			if (link && (ncr_will_link & (1<<reqp->targ_id))) {
				link->link = reqp;
				link->xcmd.bytes[link->xs->cmdlen-2] |= 1;
			}
#endif
	}
#ifdef AUTO_SENSE
		/*
		 * If we haven't already, check the target for link support.
		 * Do this by prefixing the current command with a dummy
		 * Request_Sense command, link the dummy to the current
		 * command, and insert the dummy command at the head of the
		 * issue queue.  Set the DRIVER_LINKCHK flag so that we'll
		 * ignore the results of the dummy command, since we only
		 * care about whether it was accepted or not.
		 */
		if (!link && (ncr_test_link & (1 << reqp->targ_id)) == 0 &&
		    (tmp = free_head) && (reqp->dr_flag & DRIVER_NOINT) == 0) {
			free_head = tmp->next;
			tmp->dr_flag = (reqp->dr_flag & ~DRIVER_DMAOK) |
			    DRIVER_LINKCHK;
			tmp->phase = NR_PHASE;
			tmp->msgout = MSG_NOOP;
			tmp->status = SCSGOOD;
			tmp->xs = reqp->xs;
			tmp->targ_id = reqp->targ_id;
			tmp->targ_lun = reqp->targ_lun;
			memcpy(&tmp->xcmd, sense_cmd, sizeof(sense_cmd));
			tmp->xcmd_len = sizeof(sense_cmd);
			tmp->xdata_ptr = (u_char *)&tmp->xs->sense.scsi_sense;
			tmp->xdata_len = sizeof(tmp->xs->sense.scsi_sense);
			ncr_test_link |= 1<<tmp->targ_id;
			tmp->link = reqp;
			tmp->xcmd.bytes[sizeof(sense_cmd)-2] |= 1;
			tmp->next = issue_q;
			issue_q = tmp;
#ifdef DBG_REQ
			if (dbg_target_mask & (1 << tmp->targ_id))
				show_request(tmp, "LINKCHK");
#endif
		}
#endif
		splx(sps);

#ifdef DBG_REQ
		if (dbg_target_mask & (1 << reqp->targ_id))
			show_request(reqp,
			    (reqp->xcmd.opcode == SCSI_REQUEST_SENSE) ?
			    "HEAD":"TAIL");
#endif

		run_main(sc);
		return;

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

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

static void
ncr5380_minphys(struct buf *bp)
{

	if (bp->b_bcount > MIN_PHYS)
		bp->b_bcount = MIN_PHYS;
	minphys(bp);
}
#undef MIN_PHYS

static void
ncr5380_show_scsi_cmd(struct scsipi_xfer *xs)
{
	uint8_t	*b = (uint8_t *)xs->cmd;
	int	i  = 0;

	scsipi_printaddr(xs->xs_periph);
	if ((xs->xs_control & XS_CTL_RESET) == 0) {
		while (i < xs->cmdlen) {
			if (i)
				printf(",");
			printf("%x",b[i++]);
		}
		printf("-\n");
	} else {
		printf("-RESET-\n");
	}
}

/*
 * The body of the driver.
 */
static void
scsi_main(struct ncr_softc *sc)
{
	SC_REQ	*req, *prev;
	int	itype;
	int	sps;

	/*
	 * While running in the driver SCSI-interrupts are disabled.
	 */
	scsi_idisable();
	ENABLE_NCR5380(sc);

	PID("scsi_main1");
	for (;;) {
		sps = splbio();
		if (!connected) {
			/*
			 * Check if it is fair keep any exclusive access to
			 * DMA claimed. If not, stop queueing new jobs so
			 * the discon_q will be eventually drained and DMA
			 * can be given up.
			 */
			if (!fair_to_keep_dma())
				goto main_exit;

			/*
			 * Search through the issue-queue for a command
			 * destined for a target that isn't busy.
			 */
			prev = NULL;
			for (req=issue_q; req != NULL;
			    prev = req, req = req->next) {
				if ((busy & (1 << req->targ_id)) == 0) {
					/*
					 * Found one, remove it from
					 * the issue queue.
					 */
					if (prev == NULL)
						issue_q = req->next;
					else
						prev->next = req->next;
					req->next = NULL;
					break;
				}
			}

			/*
			 * When a request has just ended, we get here
			 * before an other device detects that
			 * the bus is free and that it can reconnect.
			 * The problem is that when this happens,
			 * we always baffle the device because our
			 * (initiator) id is higher.  This can cause
			 * a sort of starvation on slow devices.
			 * So we check for a pending reselection here.
			 * Note that 'connected' will be non-null
			 * if the reselection succeeds.
			 */
			if ((GET_5380_REG(NCR5380_IDSTAT) & (SC_S_SEL|SC_S_IO))
			    == (SC_S_SEL|SC_S_IO)){
				if (req != NULL) {
					req->next = issue_q;
					issue_q = req;
				}
				splx(sps);

				reselect(sc);
				scsi_clr_ipend();
				goto connected;
			}

			/*
			 * The host is not connected and there is no request
			 * pending, exit.
			 */
			if (req == NULL) {
				PID("scsi_main2");
				goto main_exit;
			}

			/*
			 * Re-enable interrupts before handling the request.
			 */
			splx(sps);

#ifdef DBG_REQ
			if (dbg_target_mask & (1 << req->targ_id))
				show_request(req, "TARGET");
#endif
			/*
			 * We found a request. Try to connect to the target.
			 * If the initiator fails arbitration,
			 * the command is put back in the issue queue.
			 */
			if (scsi_select(req, 0)) {
				sps = splbio();
				req->next = issue_q;
				issue_q = req;
				splx(sps);
#ifdef DBG_REQ
				if (dbg_target_mask & (1 << req->targ_id))
					ncr_tprint(req, "Select failed\n");
#endif
			}
		} else
			splx(sps);
connected:
		if (connected) {
			/*
			 * If the host is currently connected but
			 * a 'real-DMA' transfer is in progress,
			 * the 'end-of-DMA' interrupt restarts main.
			 * So quit.
			 */
			sps = splbio();
			if (connected &&
			    (connected->dr_flag & DRIVER_IN_DMA)) {
				PID("scsi_main3");
				goto main_exit;
			}
			splx(sps);

			/*
			 * Let the target guide us through the bus-phases
			 */
			while (information_transfer(sc) == -1)
				continue;
		}
	}
	/* NEVER TO REACH HERE */
	show_phase(NULL, 0);	/* XXX: Get rid of not used warning */
	panic("ncr5380-SCSI: not designed to come here");

main_exit:
	/*
	 * We enter here with interrupts disabled. We are about to exit main
	 * so interrupts should be re-enabled. Because interrupts are edge
	 * triggered, we could already have missed the interrupt. Therefore
	 * we check the IRQ-line here and re-enter when we really missed a
	 * valid interrupt.
	 */
	PID("scsi_main4");
	scsi_ienable();

	/*
	 * If we're not currently connected, enable reselection
	 * interrupts.
	 */
	if (!connected)
		SET_5380_REG(NCR5380_IDSTAT, SC_HOST_ID);

	if (scsi_ipending()) {
		if ((itype = check_intr(sc)) != INTR_SPURIOUS) {
			scsi_idisable();
			scsi_clr_ipend();
			splx(sps);

			if (itype == INTR_RESEL)
				reselect(sc);
			else {
#ifdef REAL_DMA
				dma_ready();
#else
				if (pdma_ready())
					goto connected;
				panic("Got DMA interrupt without DMA");
#endif
			}
			goto connected;
		}
	}
	reconsider_dma();
	main_running = 0;
	splx(sps);
	PID("scsi_main5");
}

#ifdef REAL_DMA
/*
 * The SCSI-DMA interrupt.
 * This interrupt can only be triggered when running in non-polled DMA
 * mode. When DMA is not active, it will be silently ignored, it is usually
 * to late because the EOP interrupt of the controller happens just a tiny
 * bit earlier. It might become useful when scatter/gather is implemented,
 * because in that case only part of the DATAIN/DATAOUT transfer is taken
 * out of a single buffer.
 */
static void
ncr_dma_intr(struct ncr_softc *sc)
{
	SC_REQ	*reqp;
	int	dma_done;

	PID("ncr_dma_intr");
	if ((reqp = connected) && (reqp->dr_flag & DRIVER_IN_DMA)) {
		scsi_idisable();
		if ((dma_done = dma_ready()) == 0) {
			transfer_dma(reqp, reqp->phase, 0);
			return;
		}
		run_main(sc);
	}
}
#endif /* REAL_DMA */

/*
 * The SCSI-controller interrupt. This interrupt occurs on reselections and
 * at the end of non-polled DMA-interrupts. It is assumed to be called from
 * the machine-dependent hardware interrupt.
 */
static void
ncr_ctrl_intr(struct ncr_softc *sc)
{
	int itype;

	if (main_running)
		return; /* scsi_main() should handle this one */

	while (scsi_ipending()) {
		scsi_idisable();
		if ((itype = check_intr(sc)) != INTR_SPURIOUS) {
			if (itype == INTR_RESEL)
				reselect(sc);
			else {
#ifdef REAL_DMA
				int dma_done;
				if ((dma_done = dma_ready()) == 0) {
					transfer_dma(connected,
					    connected->phase, 0);
					return;
				}
#else
				if (pdma_ready())
					return;
				panic("Got DMA interrupt without DMA");
#endif
			}
			scsi_clr_ipend();
		}
		run_main(sc);
		return;
	}
	PID("ncr_ctrl_intr1");
}

/*
 * Initiate a connection path between the host and the target. The function
 * first goes into arbitration for the SCSI-bus. When this succeeds, the target
 * is selected and an 'IDENTIFY' message is send.
 * Returns -1 when the arbitration failed. Otherwise 0 is returned. When
 * the target does not respond (to either selection or 'MESSAGE OUT') the
 * 'done' function is executed.
 * The result code given by the driver can be influenced by setting 'code'
 * to a non-zero value. This is the case when 'select' is called by abort.
 */
static int
scsi_select(SC_REQ *reqp, int code)
{
	uint8_t			tmp[1];
	uint8_t			phase;
	u_long			cnt;
	int			sps;
	uint8_t			atn_flag;
	uint8_t			targ_bit;
	struct ncr_softc	*sc;

	sc = device_private(
	    reqp->xs->xs_periph->periph_channel->chan_adapter->adapt_dev);
	DBG_SELPRINT ("Starting arbitration\n", 0);
	PID("scsi_select1");

	sps = splbio();

	/*
	 * Prevent a race condition here. If a reslection interrupt occurred
	 * between the decision to pick a new request and the call to select,
	 * we abort the selection.
	 * Interrupts are lowered when the 5380 is setup to arbitrate for the
	 * bus.
	 */
	if (connected) {
		splx(sps);
		PID("scsi_select2");
		return -1;
	}

	/*
	 * Set phase bits to 0, otherwise the 5380 won't drive the bus during
	 * selection.
	 */
	SET_5380_REG(NCR5380_TCOM, 0);
	SET_5380_REG(NCR5380_ICOM, 0);

	/*
	 * Arbitrate for the bus.
	 */
	SET_5380_REG(NCR5380_DATA, SC_HOST_ID);
	SET_5380_REG(NCR5380_MODE, SC_ARBIT);

	splx(sps);

	cnt = 10;
	while ((GET_5380_REG(NCR5380_ICOM) & SC_AIP) == 0 && --cnt)
		delay(1);

	if ((GET_5380_REG(NCR5380_ICOM) & SC_AIP) == 0) {
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);
		DBG_SELPRINT ("Arbitration lost, bus not free\n",0);
		PID("scsi_select3");
		return -1;
	}

	/* The arbitration delay is 2.2 usecs */
	delay(3);

	/*
	 * Check the result of the arbitration. If we failed, return -1.
	 */
	if (GET_5380_REG(NCR5380_ICOM) & SC_LA) {
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);
		PID("scsi_select4");
		return -1;
	}

	/*
	 * The spec requires that we should read the data register to
	 * check for higher id's and check the SC_LA again.
	 */
	tmp[0] = GET_5380_REG(NCR5380_DATA);
	if (tmp[0] & ~((SC_HOST_ID << 1) - 1)) {
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);
		DBG_SELPRINT ("Arbitration lost, higher id present\n",0);
		PID("scsi_select5");
		return -1;
	}
	if (GET_5380_REG(NCR5380_ICOM) & SC_LA) {
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);
		DBG_SELPRINT ("Arbitration lost,deassert SC_ARBIT\n",0);
		PID("scsi_select6");
		return -1;
	}
	SET_5380_REG(NCR5380_ICOM, SC_A_SEL | SC_A_BSY);
	if (GET_5380_REG(NCR5380_ICOM) & SC_LA) {
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);
		DBG_SELPRINT ("Arbitration lost, deassert SC_A_SEL\n", 0);
		PID("scsi_select7");
		return -1;
	}
	/* Bus settle delay + Bus clear delay = 1.2 usecs */
	delay(2);
	DBG_SELPRINT ("Arbitration complete\n", 0);

	/*
	 * Now that we won the arbitration, start the selection.
	 */
	targ_bit = 1 << reqp->targ_id;
	SET_5380_REG(NCR5380_DATA, SC_HOST_ID | targ_bit);

	if (sc->sc_noselatn & targ_bit)
		atn_flag = 0;
	else
		atn_flag = SC_A_ATN;

	/*
	 * Raise ATN while SEL is true before BSY goes false from arbitration,
	 * since this is the only way to guarantee that we'll get a MESSAGE OUT
	 * phase immediately after the selection.
	 */
	SET_5380_REG(NCR5380_ICOM, SC_A_BSY | SC_A_SEL | atn_flag | SC_ADTB);
	SET_5380_REG(NCR5380_MODE, IMODE_BASE);

	/*
	 * Turn off reselection interrupts
	 */
	SET_5380_REG(NCR5380_IDSTAT, 0);

	/*
	 * Reset BSY. The delay following it, surpresses a glitch in the
	 * 5380 which causes us to see our own BSY signal instead of that of
	 * the target.
	 */
	SET_5380_REG(NCR5380_ICOM, SC_A_SEL | atn_flag | SC_ADTB);
	delay(1);

	/*
	 * Wait for the target to react, the specs call for a timeout of
	 * 250 ms.
	 */
	cnt = 25000;
	while ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY) == 0 && --cnt)
		delay(10);

	if ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY) == 0) {
		/*
		 * There is no reaction from the target, start the selection
		 * timeout procedure. We release the databus but keep SEL
		 * asserted. After that we wait a 'selection abort time' (200
		 * usecs) and 2 deskew delays (90 ns) and check BSY again.
		 * When BSY is asserted, we assume the selection succeeded,
		 * otherwise we release the bus.
		 */
		SET_5380_REG(NCR5380_ICOM, SC_A_SEL | atn_flag);
		delay(201);
		if ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY) == 0) {
			SET_5380_REG(NCR5380_ICOM, 0);
			reqp->xs->error      = code ? code : XS_SELTIMEOUT;
			DBG_SELPRINT ("Target %d not responding to sel\n",
								reqp->targ_id);
			if (reqp->dr_flag & DRIVER_LINKCHK)
				ncr_test_link &= ~(1<<reqp->targ_id);
			finish_req(reqp);
			PID("scsi_select8");
			return 0;
		}
	}
	SET_5380_REG(NCR5380_ICOM, atn_flag);

	DBG_SELPRINT ("Target %d responding to select.\n", reqp->targ_id);

	/*
	 * The SCSI-interrupts are disabled while a request is being handled.
	 */
	scsi_idisable();

	/*
	 * If we did not request ATN, then don't try to send IDENTIFY.
	 */
	if (atn_flag == 0) {
		reqp->phase = PH_CMD;
		goto identify_failed;
	}

	/*
	 * Here we prepare to send an 'IDENTIFY' message.
	 * Allow disconnect only when interrupts are allowed.
	 */
	tmp[0] = MSG_IDENTIFY(reqp->targ_lun,
	    (reqp->dr_flag & DRIVER_NOINT) ? 0 : 1);
	cnt    = 1;
	phase  = PH_MSGOUT;

	/*
	 * Since we followed the SCSI-spec and raised ATN while SEL was true
	 * but before BSY was false during the selection, a 'MESSAGE OUT'
	 * phase should follow.  Unfortunately, this does not happen on
	 * all targets (Asante ethernet devices, for example), so we must
	 * check the actual mode if the message transfer fails--if the
	 * new phase is PH_CMD and has never been successfully selected
	 * w/ATN in the past, then we assume that it is an old device
	 * that doesn't support select w/ATN.
	 */
	if (transfer_pio(&phase, tmp, &cnt, 0) || cnt) {

		if ((phase == PH_CMD) && (sc->sc_selected & targ_bit) == 0) {
			DBG_SELPRINT("Target %d: not responding to ATN.\n",
			    reqp->targ_id);
			sc->sc_noselatn |= targ_bit;
			reqp->phase = PH_CMD;
			goto identify_failed;
		}

		DBG_SELPRINT("Target %d: failed to send identify\n",
		    reqp->targ_id);
		/*
		 * Try to disconnect from the target.  We cannot leave
		 * it just hanging here.
		 */
		if (!reach_msg_out(sc, sizeof(struct scsipi_generic))) {
			u_long	len   = 1;
			uint8_t	phse  = PH_MSGOUT;
			uint8_t	msg   = MSG_ABORT;

			transfer_pio(&phse, &msg, &len, 0);
		} else
			scsi_reset_verbose(sc,
			    "Connected to unidentified target");

		SET_5380_REG(NCR5380_ICOM, 0);
		reqp->xs->error = code ? code : XS_DRIVER_STUFFUP;
		finish_req(reqp);
		PID("scsi_select9");
		return 0;
	}
	reqp->phase = PH_MSGOUT;

identify_failed:
	sc->sc_selected |= targ_bit;

#ifdef notyet /* LWP: Do we need timeouts in the driver? */
	/*
	 * Command is connected, start timer ticking.
	 */
	ccb_p->xtimeout = ccb_p->timeout + Lbolt;
#endif

	connected  = reqp;
	busy      |= targ_bit;
	PID("scsi_select10");
	return 0;
}

/*
 * Return codes:
 *	 0: Job has finished or disconnected, find something else
 *	-1: keep on calling information_transfer() from scsi_main()
 */
static int
information_transfer(struct ncr_softc *sc)
{
	SC_REQ	*reqp = connected;
	uint8_t	tmp, phase;
	u_long	len;

	PID("info_transf1");
	/*
	 * Clear pending interrupts from 5380-chip.
	 */
	scsi_clr_ipend();

	/*
	 * The SCSI-spec requires BSY to be true while connected to a target,
	 * loosing it means we lost the target...
	 * Also REQ needs to be asserted here to indicate that the bus-phase
	 * is valid. When the target does not supply REQ within a 'reasonable'
	 * amount of time, it's probably lost in it's own maze of twisting
	 * passages, we have to reset the bus to free it.
	 */
	if (GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY)
		wait_req_true();
	tmp = GET_5380_REG(NCR5380_IDSTAT);


	if ((tmp & (SC_S_BSY|SC_S_REQ)) != (SC_S_BSY|SC_S_REQ)) {
		busy           &= ~(1 << reqp->targ_id);
		connected       = NULL;
		reqp->xs->error = XS_TIMEOUT;
		finish_req(reqp);
		if ((tmp & SC_S_REQ) == 0)
			scsi_reset_verbose(sc,
					   "Timeout waiting for phase-change");
		PID("info_transf2");
		return 0;
	}

	phase = (tmp >> 2) & 7;
	if (phase != reqp->phase) {
		reqp->phase = phase;
#ifdef DBG_INF
		if (dbg_target_mask & (1 << reqp->targ_id))
			DBG_INFPRINT(show_phase, reqp, phase);
#endif
	} else {
		/*
		 * Same data-phase. If same error give up
		 */
		if ((reqp->msgout == MSG_ABORT) &&
		    ((phase == PH_DATAOUT) || (phase == PH_DATAIN))) {
			busy     &= ~(1 << reqp->targ_id);
			connected = NULL;
			reqp->xs->error = XS_TIMEOUT;
			finish_req(reqp);
			scsi_reset_verbose(sc, "Failure to abort command");
			return 0;
		}
	}

	switch (phase) {
	case PH_DATAOUT:
#ifdef DBG_NOWRITE
		ncr_tprint(reqp, "NOWRITE set -- write attempt aborted.");
		reqp->msgout = MSG_ABORT;
		SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
		return -1;
#endif /* DBG_NOWRITE */
		/*
		 * If this is the first write using DMA, fill
		 * the bounce buffer.
		 */
		if (reqp->xdata_ptr == reqp->xs->data) { /* XXX */
			if (reqp->dr_flag & DRIVER_BOUNCING)
				memcpy(reqp->bounceb, reqp->xdata_ptr,
				    reqp->xdata_len);
		}

	case PH_DATAIN:
		if (reqp->xdata_len <= 0) {
			/*
			 * Target keeps requesting data. Try to get into
			 * message-out phase by feeding/taking 100 byte.
			 */
			ncr_tprint(reqp, "Target requests too much data\n");
			reqp->msgout = MSG_ABORT;
			SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
			reach_msg_out(sc, 100);
			return -1;
		}
#ifdef REAL_DMA
		if (reqp->dr_flag & DRIVER_DMAOK) {
			int poll = REAL_DMA_POLL|(reqp->dr_flag & DRIVER_NOINT);
			transfer_dma(reqp, phase, poll);
			if (!poll)
				return 0;
		} else
#endif
		{
			PID("info_transf3");
			len = reqp->xdata_len;
#ifdef USE_PDMA
			if (transfer_pdma(&phase, reqp->xdata_ptr, &len) == 0)
				return 0;
#else
			transfer_pio(&phase, reqp->xdata_ptr, &len, 0);
#endif
			reqp->xdata_ptr += reqp->xdata_len - len;
			reqp->xdata_len  = len;
		}
		return -1;
	case PH_MSGIN:
		/*
		 * We only expect single byte messages here.
		 */
		len = 1;
		transfer_pio(&phase, &tmp, &len, 1);
		reqp->message = tmp;
		return handle_message(reqp, tmp);
	case PH_MSGOUT:
		len = 1;
		transfer_pio(&phase, &reqp->msgout, &len, 0);
		if (reqp->msgout == MSG_ABORT) {
			busy     &= ~(1 << reqp->targ_id);
			connected = NULL;
			if (!reqp->xs->error)
				reqp->xs->error = XS_DRIVER_STUFFUP;
			finish_req(reqp);
			PID("info_transf4");
			return 0;
		}
		reqp->msgout = MSG_NOOP;
		return -1;
	case PH_CMD :
		len = reqp->xcmd_len;
		transfer_pio(&phase, (uint8_t *)&reqp->xcmd, &len, 0);
		PID("info_transf5");
		return -1;
	case PH_STATUS:
		len = 1;
		transfer_pio(&phase, &tmp, &len, 0);
		reqp->status = tmp;
		PID("info_transf6");
		return -1;
	   default :
		ncr_tprint(reqp, "Unknown phase\n");
	}
	PID("info_transf7");
	return -1;
}

/*
 * Handle the message 'msg' send to us by the target.
 * Return values:
 *	 0 : The current command has completed.
 *	-1 : Get on to the next phase.
 */
static int
handle_message(SC_REQ *reqp, u_int msg)
{
	int	sps;
	SC_REQ	*prev, *req;

	PID("hmessage1");
	switch (msg) {
		/*
		 * Linking lets us reduce the time required to get
		 * the next command to the device, skipping the arbitration
		 * and selection time. In the current implementation,
		 * we merely have to start the next command pointed
		 * to by 'next_link'.
		 */
	case MSG_LINK_CMD_COMPLETE:
	case MSG_LINK_CMD_COMPLETEF:
		if (reqp->link == NULL) {
			ncr_tprint(reqp, "No link for linked command");
			nack_message(reqp, MSG_ABORT);
			PID("hmessage2");
			return -1;
		}
		ack_message();
		if ((reqp->dr_flag & DRIVER_AUTOSEN) == 0) {
			reqp->xs->resid = reqp->xdata_len;
			reqp->xs->error = 0;
		}

#ifdef AUTO_SENSE
		if (check_autosense(reqp, 1) == -1)
			return -1;
#endif /* AUTO_SENSE */

#ifdef DBG_REQ
		if (dbg_target_mask & (1 << reqp->targ_id))
			show_request(reqp->link, "LINK");
#endif
		connected = reqp->link;

		/*
		 * Unlink the 'linked' request from the issue_q
		 */
		sps  = splbio();
		prev = NULL;
		for (req = issue_q; req != NULL; prev = req, req = req->next) {
			if (req == connected)
				break;
		}
		if (req == NULL)
			panic("Inconsistent issue_q");
		if (prev == NULL)
			issue_q = req->next;
		else
			prev->next = req->next;
		req->next = NULL;
		splx(sps);

		finish_req(reqp);
		PID("hmessage3");
		return -1;
	case MSG_ABORT:
	case MSG_CMDCOMPLETE:
		ack_message();
		connected = NULL;
		busy     &= ~(1 << reqp->targ_id);
		if ((reqp->dr_flag & DRIVER_AUTOSEN) == 0) {
			reqp->xs->resid = reqp->xdata_len;
			reqp->xs->error = 0;
		}

#ifdef AUTO_SENSE
		if (check_autosense(reqp, 0) == -1) {
			PID("hmessage4");
			return 0;
		}
#endif /* AUTO_SENSE */

		finish_req(reqp);
		PID("hmessage5");
		return 0;
	case MSG_MESSAGE_REJECT:
		ack_message();
		PID("hmessage6");
		return -1;
	case MSG_DISCONNECT:
		ack_message();
#ifdef DBG_REQ
		if (dbg_target_mask & (1 << reqp->targ_id))
			show_request(reqp, "DISCON");
#endif
		sps = splbio();
		connected  = NULL;
		reqp->next = discon_q;
		discon_q   = reqp;
		splx(sps);
		PID("hmessage7");
		return 0;
	case MSG_SAVEDATAPOINTER:
	case MSG_RESTOREPOINTERS:
		/*
		 * We save pointers implicitely at disconnect.
		 * So we can ignore these messages.
		 */
		ack_message();
		PID("hmessage8");
		return -1;
	case MSG_EXTENDED:
		nack_message(reqp, MSG_MESSAGE_REJECT);
		PID("hmessage9");
		return -1;
	default:
		if ((msg & 0x80) && (msg & 0x18) == 0) {	/* IDENTIFY */
			PID("hmessage10");
			ack_message();
			return 0;
		} else {
			ncr_tprint(reqp, "Unknown message %x.  Rejecting.\n",
			    msg);
			nack_message(reqp, MSG_MESSAGE_REJECT);
		}
		return -1;
	}
	PID("hmessage11");
	return -1;
}

/*
 * Handle reselection. If a valid reconnection occurs, connected
 * points at the reconnected command. The command is removed from the
 * disconnected queue.
 */
static void
reselect(struct ncr_softc *sc)
{
	uint8_t	phase;
	u_long	len;
	uint8_t	msg;
	uint8_t	target_mask;
	int	abort = 0;
	SC_REQ	*tmp, *prev;

	PID("reselect1");
	target_mask = GET_5380_REG(NCR5380_DATA) & ~SC_HOST_ID;

	/*
	 * At this point, we have detected that our SCSI-id is on the bus,
	 * SEL is true and BSY was false for at least one bus settle
	 * delay (400 ns.).
	 * We must assert BSY ourselves, until the target drops the SEL signal.
	 * The SCSI-spec specifies no maximum time for this, so we have to
	 * choose something long enough to suit all targets.
	 */
	SET_5380_REG(NCR5380_ICOM, SC_A_BSY);
	len = 250000;
	while ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_SEL) && (len > 0)) {
		delay(1);
		len--;
	}
	if (GET_5380_REG(NCR5380_IDSTAT) & SC_S_SEL) {
		/* Damn SEL isn't dropping */
		scsi_reset_verbose(sc, "Target won't drop SEL during Reselect");
		return;
	}

	SET_5380_REG(NCR5380_ICOM, 0);

	/*
	 * Check if the reselection is still valid. Check twice because
	 * of possible line glitches - cheaper than delay(1) and we need
	 * only a few nanoseconds.
	 */
	if ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY) == 0) {
		if ((GET_5380_REG(NCR5380_IDSTAT) & SC_S_BSY) == 0) {
			ncr_aprint(sc,
			    "Stepped into the reselection timeout\n");
			return;
		}
	}

	/*
	 * Get the expected identify message.
	 */
	phase = PH_MSGIN;
	len   = 1;
	transfer_pio(&phase, &msg, &len, 0);
	if (len || !MSG_ISIDENTIFY(msg)) {
		ncr_aprint(sc, "Expecting IDENTIFY, got 0x%x\n", msg);
		abort = 1;
		tmp = NULL;
	} else {
		/*
		 * Find the command reconnecting
		 */
		for (tmp = discon_q, prev = NULL; tmp != NULL;
		    prev = tmp, tmp = tmp->next) {
			if (target_mask == (1 << tmp->targ_id)) {
				if (prev)
					prev->next = tmp->next;
				else
					discon_q = tmp->next;
				tmp->next = NULL;
				break;
			}
		}
		if (tmp == NULL) {
			ncr_aprint(sc,
			    "No disconnected job for targetmask %x\n",
			    target_mask);
			abort = 1;
		}
	}
	if (abort) {
		msg   = MSG_ABORT;
		len   = 1;
		phase = PH_MSGOUT;

		SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
		if (transfer_pio(&phase, &msg, &len, 0) || len)
			scsi_reset_verbose(sc, "Failure to abort reselection");
	} else {
		connected = tmp;
#ifdef DBG_REQ
		if (dbg_target_mask & (1 << tmp->targ_id))
			show_request(tmp, "RECON");
#endif
	}
	PID("reselect2");
}

/*
 * Transfer data in a given phase using programmed I/O.
 * Returns -1 when a different phase is entered without transferring the
 * maximum number of bytes, 0 if all bytes transferred or exit is in the same
 * phase.
 */
static int
transfer_pio(u_char *phase, u_char *data, u_long *len, int dont_drop_ack)
{
	u_int	cnt = *len;
	uint8_t	ph  = *phase;
	uint8_t	tmp, new_icom;

	DBG_PIOPRINT("SCSI: transfer_pio start: phase: %d, len: %d\n", ph,cnt);
	PID("tpio1");
	SET_5380_REG(NCR5380_TCOM, ph);
	do {
		if (!wait_req_true()) {
	    		DBG_PIOPRINT ("SCSI: transfer_pio: missing REQ\n",
			    0, 0);
			break;
		}
		if (((GET_5380_REG(NCR5380_IDSTAT) >> 2) & 7) != ph) {
	    		DBG_PIOPRINT("SCSI: transfer_pio: phase mismatch\n",
			    0, 0);
			break;
		}
		if (PH_IN(ph)) {
			*data++ = GET_5380_REG(NCR5380_DATA);
			SET_5380_REG(NCR5380_ICOM, SC_A_ACK);
			if ((cnt == 1) && dont_drop_ack)
				new_icom = SC_A_ACK;
			else
				new_icom = 0;
		} else {
			SET_5380_REG(NCR5380_DATA, *data++);

			/*
			 * The SCSI-standard suggests that in the
			 * 'MESSAGE OUT' phase, the initiator should
			 * drop ATN on the last byte of the * message phase
			 * after REQ has been asserted for the handshake
			 * but before the initiator raises ACK.
			 */
			if (!((ph == PH_MSGOUT) && (cnt > 1) )) {
				SET_5380_REG(NCR5380_ICOM, SC_ADTB);
				SET_5380_REG(NCR5380_ICOM, SC_ADTB | SC_A_ACK);
				new_icom = 0;
			} else {
				SET_5380_REG(NCR5380_ICOM, SC_ADTB | SC_A_ATN);
				SET_5380_REG(NCR5380_ICOM,
				    SC_ADTB | SC_A_ATN | SC_A_ACK);
				new_icom = SC_A_ATN;
			}
		}
		if (!wait_req_false()) {
			DBG_PIOPRINT("SCSI: transfer_pio - REQ not dropping\n",
			    0, 0);
			break;
		}
		SET_5380_REG(NCR5380_ICOM, new_icom);

	} while (--cnt);

	if ((tmp = GET_5380_REG(NCR5380_IDSTAT)) & SC_S_REQ)
		*phase = (tmp >> 2) & 7;
	else
		*phase = NR_PHASE;
	*len = cnt;
	DBG_PIOPRINT("SCSI: transfer_pio done: phase: %d, len: %d\n",
	    *phase, cnt);
	PID("tpio2");
	if (cnt == 0 || (*phase == ph))
		return 0;
	return -1;
}

#ifdef REAL_DMA

/*
 * Start a DMA-transfer on the device using the current pointers.
 * If 'poll' is true, the function busy-waits until DMA has completed.
 */
static void
transfer_dma(SC_REQ *reqp, u_int phase, int poll)
{
	int	dma_done;
	uint8_t	mbase = 0;
	int	sps;

again:
	PID("tdma1");

	/*
	 * We should be in phase, otherwise we are not allowed to
	 * drive the bus.
	 */
	SET_5380_REG(NCR5380_TCOM, phase);

	/*
	 * Defer interrupts until DMA is fully running.
	 */
	sps = splbio();

	/*
	 * Clear pending interrupts and parity errors.
	 */
	scsi_clr_ipend();

	if (!poll) {
		/*
		 * Enable SCSI interrupts and set IN_DMA flag, set 'mbase'
		 * to the interrupts we want enabled.
		 */
		scsi_ienable();
		reqp->dr_flag |= DRIVER_IN_DMA;
		mbase = SC_E_EOPI | SC_MON_BSY;
	} else
		scsi_idisable();
	mbase |=  IMODE_BASE | SC_M_DMA;
	scsi_dma_setup(reqp, phase, mbase);

	splx(sps);

	if (poll) {
		/*
		 * On polled-DMA transfers, we wait here until the
		 * 'end-of-DMA' condition occurs.
		 */
		poll_edma(reqp);
		if ((dma_done = dma_ready()) == 0)
			goto again;
	}
	PID("tdma2");
}

/*
 * Check results of a DMA data-transfer.
 */
static int
dma_ready(void)
{
	SC_REQ	*reqp = connected;
	int	dmstat, is_edma;
	long	bytes_left, bytes_done;

	is_edma = get_dma_result(reqp, &bytes_left);
	dmstat  = GET_5380_REG(NCR5380_DMSTAT);

	/*
	 * Check if the call is sensible and not caused by any spurious
	 * interrupt.
	 */
	if (!is_edma &&
	    (dmstat & (SC_END_DMA|SC_BSY_ERR)) == 0 &&
	    (dmstat & SC_PHS_MTCH) != 0) {
		ncr_tprint(reqp, "dma_ready: spurious call "
		    "(dm:%x,last_hit: %s)\n",
#ifdef DBG_PID
		    dmstat, last_hit[DBG_PID-1]);
#else
		    dmstat, "unknown");
#endif
		return 0;
	}

	/*
	 * Clear all (pending) interrupts.
	 */
	scsi_clr_ipend();

	/*
	 * Update various transfer-pointers/lengths
	 */
	bytes_done = reqp->dm_cur->dm_count - bytes_left;

	if ((reqp->dr_flag & DRIVER_BOUNCING) && (PH_IN(reqp->phase))) {
		/*
		 * Copy the bytes read until now from the bounce buffer
		 * to the 'real' destination. Flush the data-cache
		 * before copying.
		 */
		PCIA();
		memcpy(reqp->xdata_ptr, reqp->bouncerp, bytes_done);
		reqp->bouncerp += bytes_done;
	}

	reqp->xdata_ptr  = &reqp->xdata_ptr[bytes_done];	/* XXX */
	reqp->xdata_len -= bytes_done;				/* XXX */
	if ((reqp->dm_cur->dm_count -= bytes_done) == 0)
		reqp->dm_cur++;
	else
		reqp->dm_cur->dm_addr += bytes_done;

	if (PH_IN(reqp->phase) && (dmstat & SC_PAR_ERR)) {
		if ((ncr5380_no_parchk & (1 << reqp->targ_id)) == 0) {
			ncr_tprint(reqp, "parity error in data-phase\n");
			reqp->xs->error = XS_TIMEOUT;
		}
	}

	/*
	 * DMA mode should always be reset even when we will continue with the
	 * next chain. It is also essential to clear the MON_BUSY because
	 * when LOST_BUSY is unexpectedly set, we will not be able to drive
	 * the bus....
	 */
	SET_5380_REG(NCR5380_MODE, IMODE_BASE);


	if ((dmstat & SC_BSY_ERR) != 0 || (dmstat & SC_PHS_MTCH) == 0 ||
	    (reqp->dm_cur > reqp->dm_last) || reqp->xs->error != 0) {

		/*
		 * Tell interrupt functions DMA mode has ended.
		 */
		reqp->dr_flag &= ~DRIVER_IN_DMA;

		/*
		 * Clear mode and icom
		 */
		SET_5380_REG(NCR5380_MODE, IMODE_BASE);
		SET_5380_REG(NCR5380_ICOM, 0);

		if (dmstat & SC_BSY_ERR) {
			if (reqp->xs->error == 0)
				reqp->xs->error = XS_TIMEOUT;
			finish_req(reqp);
			PID("dma_ready1");
			return 1;
		}

		if (reqp->xs->error != 0) {
			ncr_tprint(reqp, "dma-ready: code = %d\n",
			    reqp->xs->error); /* LWP */
			reqp->msgout = MSG_ABORT;
			SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
		}
		PID("dma_ready2");
		return 1;
	}
	return 0;
}
#endif /* REAL_DMA */

static int
check_autosense(SC_REQ *reqp, int linked)
{
	int sps;

	/*
	 * If this is the driver's Link Check for this target, ignore
	 * the results of the command.  All we care about is whether we
	 * got here from a LINK_CMD_COMPLETE or CMD_COMPLETE message.
	 */
	PID("linkcheck");
	if (reqp->dr_flag & DRIVER_LINKCHK) {
		if (linked)
			ncr_will_link |= 1<<reqp->targ_id;
		else
			ncr_tprint(reqp, "Does not support linked commands\n");
		return 0;
	}
	/*
	 * If we not executing an auto-sense and the status code
	 * is request-sense, we automatically issue a request
	 * sense command.
	 */
	PID("cautos1");
	if ((reqp->dr_flag & DRIVER_AUTOSEN) == 0) {
		switch (reqp->status & SCSMASK) {
		case SCSCHKC:
			memcpy(&reqp->xcmd, sense_cmd, sizeof(sense_cmd));
			reqp->xcmd_len = sizeof(sense_cmd);
			reqp->xdata_ptr = (u_char *)&reqp->xs->sense.scsi_sense;
			reqp->xdata_len = sizeof(reqp->xs->sense.scsi_sense);
			reqp->dr_flag  |= DRIVER_AUTOSEN;
			reqp->dr_flag  &= ~DRIVER_DMAOK;
			if (!linked) {
				sps = splbio();
				reqp->next = issue_q;
				issue_q    = reqp;
				splx(sps);
			} else
				reqp->xcmd.bytes[sizeof(sense_cmd)-2] |= 1;

#ifdef DBG_REQ
			memset(reqp->xdata_ptr, 0, reqp->xdata_len);
			if (dbg_target_mask & (1 << reqp->targ_id))
				show_request(reqp, "AUTO-SENSE");
#endif
			PID("cautos2");
			return -1;
		case SCSBUSY:
			reqp->xs->error = XS_BUSY;
			return 0;
		}
	} else {
		/*
		 * An auto-sense has finished
		 */
		if ((reqp->status & SCSMASK) != SCSGOOD)
			reqp->xs->error = XS_DRIVER_STUFFUP; /* SC_E_AUTOSEN; */
		else
			reqp->xs->error = XS_SENSE;
		reqp->status = SCSCHKC;
	}
	PID("cautos3");
	return 0;
}

static int
reach_msg_out(struct ncr_softc *sc, u_long len)
{
	uint8_t	phase;
	uint8_t	data;
	u_long	n = len;

	ncr_aprint(sc, "Trying to reach Message-out phase\n");
	if ((phase = GET_5380_REG(NCR5380_IDSTAT)) & SC_S_REQ)
		phase = (phase >> 2) & 7;
	else
		return -1;
	ncr_aprint(sc, "Trying to reach Message-out phase, now: %d\n", phase);
	if (phase == PH_MSGOUT)
		return 0;

	SET_5380_REG(NCR5380_TCOM, phase);

	do {
		if (!wait_req_true())
			break;
		if (((GET_5380_REG(NCR5380_IDSTAT) >> 2) & 7) != phase)
			break;
		if (PH_IN(phase)) {
			data = GET_5380_REG(NCR5380_DATA);
			SET_5380_REG(NCR5380_ICOM, SC_A_ACK | SC_A_ATN);
		} else {
			SET_5380_REG(NCR5380_DATA, 0);
			SET_5380_REG(NCR5380_ICOM, SC_ADTB|SC_A_ATN);
			SET_5380_REG(NCR5380_ICOM, SC_ADTB|SC_A_ACK|SC_A_ATN);
		}
		if (!wait_req_false())
			break;
		SET_5380_REG(NCR5380_ICOM, SC_A_ATN);
	} while (--n);

	if ((phase = GET_5380_REG(NCR5380_IDSTAT)) & SC_S_REQ) {
		phase = (phase >> 2) & 7;
		if (phase == PH_MSGOUT) {
			ncr_aprint(sc, "Message-out phase reached after "
					"%ld bytes.\n", len - n);
			return 0;
		}
		ncr_aprint(sc, "Phase now: %d after %ld bytes.\n",
		    phase, len - n);

	}
	return -1;
}

void
scsi_reset(void)
{
	SC_REQ	*tmp, *next;
	int	sps;

	PID("scsi_reset1");
	sps = splbio();
	SET_5380_REG(NCR5380_ICOM, SC_A_RST);
	delay(100);
	SET_5380_REG(NCR5380_ICOM, 0);
	scsi_clr_ipend();

	/*
	 * None of the jobs in the discon_q will ever be reconnected,
	 * notify this to the higher level code.
	 */
	for (tmp = discon_q; tmp ;) {
		next = tmp->next;
		tmp->next = NULL;
		tmp->xs->error = XS_TIMEOUT;
		busy &= ~(1 << tmp->targ_id);
		finish_req(tmp);
		tmp = next;
	}
	discon_q = NULL;

	/*
	 * The current job will never finish either.
	 * The problem is that we can't finish the job because an instance
	 * of main is running on it. Our best guess is that the job is currently
	 * doing REAL-DMA. In that case 'dma_ready()' should correctly finish
	 * the job because it detects BSY-loss.
	 */
	if ((tmp = connected) != NULL) {
		if (tmp->dr_flag & DRIVER_IN_DMA) {
			tmp->xs->error = XS_DRIVER_STUFFUP;
#ifdef REAL_DMA
			dma_ready();
#endif
		}
	}
	splx(sps);
	PID("scsi_reset2");

	/*
	 * Give the attached devices some time to handle the reset. This
	 * value is arbitrary but should be relatively long.
	 */
	delay(100000);
}

static void
scsi_reset_verbose(struct ncr_softc *sc, const char *why)
{

	ncr_aprint(sc, "Resetting SCSI-bus (%s)\n", why);

	scsi_reset();
}

/*
 * Check validity of the IRQ set by the 5380. If the interrupt is valid,
 * the appropriate action is carried out (reselection or DMA ready) and
 * INTR_RESEL or INTR_DMA is returned. Otherwise a console notice is written
 * and INTR_SPURIOUS is returned.
 */
static int
check_intr(struct ncr_softc *sc)
{
	SC_REQ	*reqp;

	if ((GET_5380_REG(NCR5380_IDSTAT) & (SC_S_SEL|SC_S_IO)) ==
	    (SC_S_SEL|SC_S_IO))
		return INTR_RESEL;
	else {
		if ((reqp = connected) && (reqp->dr_flag & DRIVER_IN_DMA)){
			reqp->dr_flag &= ~DRIVER_IN_DMA;
			return INTR_DMA;
		}
	}
	printf("-->");
	scsi_show();
	scsi_clr_ipend();
	ncr_aprint(sc, "Spurious interrupt.\n");
	return INTR_SPURIOUS;
}

#ifdef REAL_DMA
/*
 * Check if DMA can be used for this request. This function also builds
 * the DMA-chain.
 */
static int
scsi_dmaok(SC_REQ *reqp)
{
	u_long			phy_buf;
	u_long			phy_len;
	uint8_t			*req_addr;
	u_long			req_len;
	struct dma_chain	*dm;

	/*
	 * To be safe, do not use DMA for Falcon
	 */
	if (machineid & ATARI_FALCON)
		return 0;

	/*
	 * Initialize locals and requests' DMA-chain.
	 */
	req_len        = reqp->xdata_len;
	req_addr       = (uint8_t *)reqp->xdata_ptr;
	dm             = reqp->dm_cur = reqp->dm_last = reqp->dm_chain;
	dm->dm_count   = dm->dm_addr = 0;
	reqp->dr_flag &= ~DRIVER_BOUNCING;

	/*
	 * Do not accept zero length DMA.
	 */
	if (req_len == 0)
		return 0;

	/*
	 * If DMA is emulated in software, we don't have to breakup the
	 * request. Just build a chain with a single element and stash in
	 * the KVA and not the KPA.
	 */
	if (emulated_dma()) {
		dm->dm_addr    = (u_long)req_addr;
		dm->dm_count   = req_len;
		return 1;
	}

	/*
	 * LWP: I think that this restriction is not strictly nessecary.
	 */
	if ((req_len & 0x1) || ((u_int)req_addr & 0x3))
		return 0;

	/*
	 * Build the DMA-chain.
	 */
	dm->dm_addr = phy_buf = kvtop(req_addr);
	while (req_len) {
		if (req_len <
		    (phy_len = PAGE_SIZE - ((u_long)req_addr & PGOFSET)))
			phy_len = req_len;

		req_addr     += phy_len;
		req_len      -= phy_len;
		dm->dm_count += phy_len;

		if (req_len) {
			u_long	tmp = kvtop(req_addr);

			if ((phy_buf + phy_len) != tmp) {
				if (wrong_dma_range(reqp, dm)) {
					if (reqp->dr_flag & DRIVER_BOUNCING)
						goto bounceit;
					return 0;
				}

				if (++dm >= &reqp->dm_chain[MAXDMAIO]) {
					ncr_tprint(reqp,
					    "dmaok: DMA chain too long!\n");
					return 0;
				}
				dm->dm_count = 0;
				dm->dm_addr  = tmp;
			}
			phy_buf = tmp;
		}
	}
        if (wrong_dma_range(reqp, dm)) {
		if (reqp->dr_flag & DRIVER_BOUNCING)
			goto bounceit;
		return 0;
	}
	reqp->dm_last = dm;
	return 1;

bounceit:
	if ((reqp->bounceb = alloc_bounceb(reqp->xdata_len)) == NULL) {
		/*
		 * If we can't get a bounce buffer, forget DMA
		 */
		reqp->dr_flag &= ~DRIVER_BOUNCING;
		return 0;
	}
	/*
	 * Initialize a single DMA-range containing the bounced request
	 */
	dm = reqp->dm_cur = reqp->dm_last = reqp->dm_chain;
	dm->dm_addr    = kvtop(reqp->bounceb);
	dm->dm_count   = reqp->xdata_len;
	reqp->bouncerp = reqp->bounceb;

	return 1;
}
#endif /* REAL_DMA */

static void
run_main(struct ncr_softc *sc)
{
	int sps = splbio();

	if (!main_running) {
		/*
		 * If shared resources are required, claim them
		 * before entering 'scsi_main'. If we can't get them
		 * now, assume 'run_main' will be called when the resource
		 * becomes available.
		 */
		if (!claimed_dma()) {
			splx(sps);
			return;
		}
		main_running = 1;
		splx(sps);
		scsi_main(sc);
	} else
		splx(sps);
}

/*
 * Prefix message with full target info.
 */
static void
ncr_tprint(SC_REQ *reqp, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	scsipi_printaddr(reqp->xs->xs_periph);
	vprintf(fmt, ap);
	va_end(ap);
}

/*
 * Prefix message with adapter info.
 */
static void
ncr_aprint(struct ncr_softc *sc, const char *fmt, ...)
{
	va_list	ap;
	char buf[256];

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	printf("%s: %s", device_xname(sc->sc_dev), buf);
}
/****************************************************************************
 *		Start Debugging Functions				    *
 ****************************************************************************/
static const char *phase_names[] = {
	"DATA_OUT", "DATA_IN", "COMMAND", "STATUS", "NONE", "NONE", "MSG_OUT",
	"MSG_IN"
};

static void
show_phase(SC_REQ *reqp, int phase)
{

	printf("INFTRANS: %d Phase = %s\n", reqp->targ_id, phase_names[phase]);
}

static void
show_data_sense(struct scsipi_xfer *xs)
{
	uint8_t	*p1, *p2;
	int	i;

	p1 = (uint8_t *)xs->cmd;
	p2 = (uint8_t *)&xs->sense.scsi_sense;
	if (*p2 == 0)
		return;	/* No(n)sense */
	printf("cmd[%d]: ", xs->cmdlen);
	for (i = 0; i < xs->cmdlen; i++)
		printf("%x ", p1[i]);
	printf("\nsense: ");
	for (i = 0; i < sizeof(xs->sense.scsi_sense); i++)
		printf("%x ", p2[i]);
	printf("\n");
}

static void
show_request(SC_REQ *reqp, const char *qtxt)
{

	printf("REQ-%s: %d %p[%ld] "
	    "cmd[0]=%x S=%x M=%x R=%x resid=%d dr_flag=%x %s\n",
	    qtxt, reqp->targ_id, reqp->xdata_ptr, reqp->xdata_len,
	    reqp->xcmd.opcode, reqp->status, reqp->message,
	    reqp->xs->error, reqp->xs->resid, reqp->dr_flag,
	    reqp->link ? "L":"");
	if (reqp->status == SCSCHKC)
		show_data_sense(reqp->xs);
}

static const char *sig_names[] = {
	"PAR", "SEL", "I/O", "C/D", "MSG", "REQ", "BSY", "RST",
	"ACK", "ATN", "LBSY", "PMATCH", "IRQ", "EPAR", "DREQ", "EDMA"
};

static void
show_signals(uint8_t dmstat, uint8_t idstat)
{
	u_short	tmp, mask;
	int	j, need_pipe;

	tmp = idstat | ((dmstat & 3) << 8);
	printf("Bus signals (%02x/%02x): ", idstat, dmstat & 3);
	for (mask = 1, j = need_pipe = 0; mask <= tmp; mask <<= 1, j++) {
		if (tmp & mask)
			printf("%s%s", need_pipe++ ? "|" : "", sig_names[j]);
	}
	printf("\nDma status (%02x): ", dmstat);
	for (mask = 4, j = 10, need_pipe = 0; mask <= dmstat; mask <<= 1, j++) {
		if (dmstat & mask)
			printf("%s%s", need_pipe++ ? "|" : "", sig_names[j]);
	}
	printf("\n");
}

void
scsi_show(void)
{
	SC_REQ	*tmp;
	int	sps = splhigh();
	uint8_t	idstat, dmstat;
	int	i;

	printf("scsi_show: scsi_main is%s running\n",
	    main_running ? "" : " not");
	for (tmp = issue_q; tmp; tmp = tmp->next)
		show_request(tmp, "ISSUED");
	for (tmp = discon_q; tmp; tmp = tmp->next)
		show_request(tmp, "DISCONNECTED");
	if (connected)
		show_request(connected, "CONNECTED");
	if (can_access_5380()) {
		idstat = GET_5380_REG(NCR5380_IDSTAT);
		dmstat = GET_5380_REG(NCR5380_DMSTAT);
		show_signals(dmstat, idstat);
	}

	if (connected)
		printf("phase = %d, ", connected->phase);
	printf("busy:%x, spl:%04x\n", busy, sps);
#ifdef	DBG_PID
	for (i=0; i<DBG_PID; i++)
		printf("\t%d\t%s\n", i, last_hit[i]);
#endif

	splx(sps);
}