xref: /src/sys/arch/next68k/dev/esp.c

/*	$NetBSD: esp.c,v 1.6 1998/08/15 05:16:43 mycroft Exp $	*/

/*-
 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace
 * Simulation Facility, NASA Ames Research Center.
 *
 * 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 NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1994 Peter Galbavy
 * Copyright (c) 1995 Paul Kranenburg
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Peter Galbavy
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 */

/*
 * Based on aic6360 by Jarle Greipsland
 *
 * Acknowledgements: Many of the algorithms used in this driver are
 * inspired by the work of Julian Elischer (julian (at) tfs.com) and
 * Charles Hannum (mycroft (at) duality.gnu.ai.mit.edu).  Thanks a million!
 */

/*
 * Grabbed from the sparc port at revision 1.73 for the NeXT.
 * Darrin B. Jewell <dbj (at) netbsd.org>  Sat Jul  4 15:41:32 1998
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/queue.h>

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

#include <machine/bus.h>
#include <machine/autoconf.h>
#include <machine/cpu.h>

#include <dev/ic/ncr53c9xreg.h>
#include <dev/ic/ncr53c9xvar.h>

#include <next68k/next68k/isr.h>

#include <next68k/dev/nextdmareg.h>
#include <next68k/dev/nextdmavar.h>

#include "espreg.h"
#include "espvar.h"

#if 1
#define ESP_DEBUG
#endif

#ifdef ESP_DEBUG
#define DPRINTF(x) printf x;
#else
#define DPRINTF(x)
#endif


void	espattach_intio	__P((struct device *, struct device *, void *));
int	espmatch_intio	__P((struct device *, struct cfdata *, void *));

/* DMA callbacks */
bus_dmamap_t esp_dmacb_continue __P((void *arg));
void esp_dmacb_completed __P((bus_dmamap_t map, void *arg));
void esp_dmacb_shutdown __P((void *arg));

/* Linkup to the rest of the kernel */
struct cfattach esp_ca = {
	sizeof(struct esp_softc), espmatch_intio, espattach_intio
};

struct scsipi_adapter esp_switch = {
	ncr53c9x_scsi_cmd,
	minphys,		/* no max at this level; handled by DMA code */
	NULL,
	NULL,
};

struct scsipi_device esp_dev = {
	NULL,			/* Use default error handler */
	NULL,			/* have a queue, served by this */
	NULL,			/* have no async handler */
	NULL,			/* Use default 'done' routine */
};

/*
 * Functions and the switch for the MI code.
 */
u_char	esp_read_reg __P((struct ncr53c9x_softc *, int));
void	esp_write_reg __P((struct ncr53c9x_softc *, int, u_char));
int	esp_dma_isintr __P((struct ncr53c9x_softc *));
void	esp_dma_reset __P((struct ncr53c9x_softc *));
int	esp_dma_intr __P((struct ncr53c9x_softc *));
int	esp_dma_setup __P((struct ncr53c9x_softc *, caddr_t *,
	    size_t *, int, size_t *));
void	esp_dma_go __P((struct ncr53c9x_softc *));
void	esp_dma_stop __P((struct ncr53c9x_softc *));
int	esp_dma_isactive __P((struct ncr53c9x_softc *));

struct ncr53c9x_glue esp_glue = {
	esp_read_reg,
	esp_write_reg,
	esp_dma_isintr,
	esp_dma_reset,
	esp_dma_intr,
	esp_dma_setup,
	esp_dma_go,
	esp_dma_stop,
	esp_dma_isactive,
	NULL,			/* gl_clear_latched_intr */
};

int
espmatch_intio(parent, cf, aux)
	struct device *parent;
	struct cfdata *cf;
	void *aux;
{
  /* should probably probe here */
  /* Should also probably set up data from config */

#if 1
/* this code isn't working yet, don't match on it */
	return(0);
#else
	return(1);
#endif
}

void
espattach_intio(parent, self, aux)
	struct device *parent, *self;
	void *aux;
{
	struct esp_softc *esc = (void *)self;
	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;

	esc->sc_bst = NEXT68K_INTIO_BUS_SPACE;
	if (bus_space_map(esc->sc_bst, NEXT_P_SCSI,
			ESP_DEVICE_SIZE, 0, &esc->sc_bsh)) {
    panic("\n%s: can't map ncr53c90 registers",
				sc->sc_dev.dv_xname);
	}

	sc->sc_id = 7;
	sc->sc_freq = 20;							/* Mhz */

	/*
	 * Set up glue for MI code early; we use some of it here.
	 */
	sc->sc_glue = &esp_glue;

	/*
	 * XXX More of this should be in ncr53c9x_attach(), but
	 * XXX should we really poke around the chip that much in
	 * XXX the MI code?  Think about this more...
	 */

	/*
	 * It is necessary to try to load the 2nd config register here,
	 * to find out what rev the esp chip is, else the ncr53c9x_reset
	 * will not set up the defaults correctly.
	 */
	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_RPE;
	sc->sc_cfg3 = NCRCFG3_CDB;
	NCR_WRITE_REG(sc, NCR_CFG2, sc->sc_cfg2);

	if ((NCR_READ_REG(sc, NCR_CFG2) & ~NCRCFG2_RSVD) !=
	    (NCRCFG2_SCSI2 | NCRCFG2_RPE)) {
		sc->sc_rev = NCR_VARIANT_ESP100;
	} else {
		sc->sc_cfg2 = NCRCFG2_SCSI2;
		NCR_WRITE_REG(sc, NCR_CFG2, sc->sc_cfg2);
		sc->sc_cfg3 = 0;
		NCR_WRITE_REG(sc, NCR_CFG3, sc->sc_cfg3);
		sc->sc_cfg3 = (NCRCFG3_CDB | NCRCFG3_FCLK);
		NCR_WRITE_REG(sc, NCR_CFG3, sc->sc_cfg3);
		if (NCR_READ_REG(sc, NCR_CFG3) !=
		    (NCRCFG3_CDB | NCRCFG3_FCLK)) {
			sc->sc_rev = NCR_VARIANT_ESP100A;
		} else {
			/* NCRCFG2_FE enables > 64K transfers */
			sc->sc_cfg2 |= NCRCFG2_FE;
			sc->sc_cfg3 = 0;
			NCR_WRITE_REG(sc, NCR_CFG3, sc->sc_cfg3);
			sc->sc_rev = NCR_VARIANT_ESP200;
		}
	}

	/*
	 * XXX minsync and maxxfer _should_ be set up in MI code,
	 * XXX but it appears to have some dependency on what sort
	 * XXX of DMA we're hooked up to, etc.
	 */

	/*
	 * This is the value used to start sync negotiations
	 * Note that the NCR register "SYNCTP" is programmed
	 * in "clocks per byte", and has a minimum value of 4.
	 * The SCSI period used in negotiation is one-fourth
	 * of the time (in nanoseconds) needed to transfer one byte.
	 * Since the chip's clock is given in MHz, we have the following
	 * formula: 4 * period = (1000 / freq) * 4
	 */
	sc->sc_minsync = 1000 / sc->sc_freq;

	/*
	 * Alas, we must now modify the value a bit, because it's
	 * only valid when can switch on FASTCLK and FASTSCSI bits
	 * in config register 3...
	 */
	switch (sc->sc_rev) {
	case NCR_VARIANT_ESP100:
		sc->sc_maxxfer = 64 * 1024;
		sc->sc_minsync = 0;	/* No synch on old chip? */
		break;

	case NCR_VARIANT_ESP100A:
		sc->sc_maxxfer = 64 * 1024;
		/* Min clocks/byte is 5 */
		sc->sc_minsync = ncr53c9x_cpb2stp(sc, 5);
		break;

	case NCR_VARIANT_ESP200:
		sc->sc_maxxfer = 16 * 1024 * 1024;
		/* XXX - do actually set FAST* bits */
		break;
	}

	/* @@@ Some ESP_DCTL bits probably need setting */
	NCR_WRITE_REG(sc, ESP_DCTL,
			ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_RESET);
	DELAY(10);
	NCR_WRITE_REG(sc, ESP_DCTL, ESPDCTL_20MHZ | ESPDCTL_INTENB);
	DELAY(10);

	/* Set up SCSI DMA */
	{
		esc->sc_scsi_dma.nd_bst = NEXT68K_INTIO_BUS_SPACE;

		if (bus_space_map(esc->sc_scsi_dma.nd_bst, NEXT_P_SCSI_CSR,
				sizeof(struct dma_dev),0, &esc->sc_scsi_dma.nd_bsh)) {
			panic("\n%s: can't map scsi DMA registers",
					sc->sc_dev.dv_xname);
		}

		esc->sc_scsi_dma.nd_intr = NEXT_I_SCSI_DMA;
		esc->sc_scsi_dma.nd_chaining_flag = 0;
		esc->sc_scsi_dma.nd_shutdown_cb  = &esp_dmacb_shutdown;
		esc->sc_scsi_dma.nd_continue_cb  = &esp_dmacb_continue;
		esc->sc_scsi_dma.nd_completed_cb = &esp_dmacb_completed;
		esc->sc_scsi_dma.nd_cb_arg       = sc;
		nextdma_config(&esc->sc_scsi_dma);
		nextdma_init(&esc->sc_scsi_dma);

		{
			int error;
			if ((error = bus_dmamap_create(esc->sc_scsi_dma.nd_dmat,
					sc->sc_maxxfer, 1, sc->sc_maxxfer,
					0, BUS_DMA_ALLOCNOW, &esc->sc_dmamap)) != 0) {
				panic("%s: can't create i/o DMA map, error = %d",
						sc->sc_dev.dv_xname,error);
			}
		}
	}

#if 0
	/* Turn on target selection using the `dma' method */
	ncr53c9x_dmaselect = 1;
#else
	ncr53c9x_dmaselect = 0;
#endif

	esc->sc_slop_bgn_addr = 0;
	esc->sc_slop_bgn_size = 0;
	esc->sc_slop_end_addr = 0;
	esc->sc_slop_end_size = 0;
	esc->sc_datain = -1;

	/* Establish interrupt channel */
	isrlink_autovec((int(*)__P((void*)))ncr53c9x_intr, sc,
			NEXT_I_IPL(NEXT_I_SCSI), 0);
	INTR_ENABLE(NEXT_I_SCSI);

	/* register interrupt stats */
	evcnt_attach(&sc->sc_dev, "intr", &sc->sc_intrcnt);

	/* Do the common parts of attachment. */
	ncr53c9x_attach(sc, &esp_switch, &esp_dev);
}

/*
 * Glue functions.
 */

u_char
esp_read_reg(sc, reg)
	struct ncr53c9x_softc *sc;
	int reg;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	return(bus_space_read_1(esc->sc_bst, esc->sc_bsh, reg));
}

void
esp_write_reg(sc, reg, val)
	struct ncr53c9x_softc *sc;
	int reg;
	u_char val;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	bus_space_write_1(esc->sc_bst, esc->sc_bsh, reg, val);
}

int
esp_dma_isintr(sc)
	struct ncr53c9x_softc *sc;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	int r = (INTR_OCCURRED(NEXT_I_SCSI));

	if (r) {
		DPRINTF(("esp_dma_isintr = %d\n",r));

		if (esc->sc_datain) {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMARD);
		} else {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB);
		}
	}

	return (r);
}

void
esp_dma_reset(sc)
	struct ncr53c9x_softc *sc;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	nextdma_reset(&esc->sc_scsi_dma);

	if (esc->sc_dmamap->dm_mapsize != 0) {
		bus_dmamap_unload(esc->sc_scsi_dma.nd_dmat, esc->sc_dmamap);
	}

	esc->sc_slop_bgn_addr = 0;
	esc->sc_slop_bgn_size = 0;
	esc->sc_slop_end_addr = 0;
	esc->sc_slop_end_size = 0;
	esc->sc_datain = -1;
}

int
esp_dma_intr(sc)
	struct ncr53c9x_softc *sc;
{
	int trans;
	int resid;
	int datain;
	struct esp_softc *esc = (struct esp_softc *)sc;

	datain = esc->sc_datain;

	DPRINTF(("esp_dma_intr resetting dma\n"));

	/* If the dma hasn't finished when we are in a scsi
	 * interrupt. Then, "Houston, we have a problem."
	 * Stop DMA and figure out how many bytes were transferred
	 */
	esp_dma_reset(sc);

	resid = 0;

	/*
	 * If a transfer onto the SCSI bus gets interrupted by the device
	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
	 * as residual since the ESP counter registers get decremented as
	 * bytes are clocked into the FIFO.
	 */

	if (! datain) {
		resid = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF);
		if (resid) {
			NCR_DMA(("dmaintr: empty esp FIFO of %d ", resid));
			NCRCMD(sc, NCRCMD_FLUSH);
			DELAY(1);
		}
	}

	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
		/*
		 * `Terminal count' is off, so read the residue
		 * out of the ESP counter registers.
		 */
		resid += (NCR_READ_REG(sc, NCR_TCL) |
			  (NCR_READ_REG(sc, NCR_TCM) << 8) |
			   ((sc->sc_cfg2 & NCRCFG2_FE)
				? (NCR_READ_REG(sc, NCR_TCH) << 16)
				: 0));

		if (resid == 0 && esc->sc_dmasize == 65536 &&
		    (sc->sc_cfg2 & NCRCFG2_FE) == 0)
			/* A transfer of 64K is encoded as `TCL=TCM=0' */
			resid = 65536;
	}

	trans = esc->sc_dmasize - resid;
	if (trans < 0) {			/* transferred < 0 ? */
#if 0
		/*
		 * This situation can happen in perfectly normal operation
		 * if the ESP is reselected while using DMA to select
		 * another target.  As such, don't print the warning.
		 */
		printf("%s: xfer (%d) > req (%d)\n",
		    esc->sc_dev.dv_xname, trans, esc->sc_dmasize);
#endif
		trans = esc->sc_dmasize;
	}

	NCR_DMA(("dmaintr: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
		NCR_READ_REG(sc, NCR_TCL),
		NCR_READ_REG(sc, NCR_TCM),
		(sc->sc_cfg2 & NCRCFG2_FE)
			? NCR_READ_REG(sc, NCR_TCH) : 0,
		trans, resid));

	*esc->sc_dmalen -= trans;
	*esc->sc_dmaaddr += trans;

	return 0;
}

int
esp_dma_setup(sc, addr, len, datain, dmasize)
	struct ncr53c9x_softc *sc;
	caddr_t *addr;
	size_t *len;
	int datain;
	size_t *dmasize;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	/* Save these in case we have to abort DMA */
	esc->sc_dmaaddr = addr;
	esc->sc_dmalen = len;
	esc->sc_dmasize = *dmasize;

	DPRINTF(("esp_dma_setup(0x%08lx,0x%08lx)\n",*addr,*dmasize));

#ifdef DIAGNOSTIC
	if ((esc->sc_datain != -1) ||
			(esc->sc_dmamap->dm_mapsize != 0)) {
		panic("%s: map already loaded in esp_dma_setup\n"
				"\tdatain = %d\n\tmapsize=%d",
				sc->sc_dev.dv_xname,esc->sc_datain,esc->sc_dmamap->dm_mapsize);
	}
#endif

	/* Deal with DMA alignment issues, by stuffing the FIFO.
	 * This assumes that if bus_dmamap_load is given an aligned
	 * buffer, then it will generate aligned hardware addresses
	 * to give to the device.  Perhaps that is not a good assumption,
	 * but it is probably true. [dbj (at) netbsd.org:19980719.0135EDT]
	 */
	{
		int slop_bgn_size; /* # bytes to be fifo'd at beginning */
		int slop_end_size; /* # bytes to be fifo'd at end */

		{
			u_long bgn = (u_long)(*addr);
			u_long end = (u_long)(*addr+*dmasize);

			slop_bgn_size = DMA_BEGINALIGNMENT-(bgn % DMA_BEGINALIGNMENT);
			if (slop_bgn_size == DMA_BEGINALIGNMENT) slop_bgn_size = 0;
			slop_end_size = end % DMA_ENDALIGNMENT;
		}

		/* Check to make sure we haven't counted the slop twice
		 * as would happen for a very short dma buffer */
		if (slop_bgn_size+slop_end_size > *dmasize) {
#if defined(DIAGNOSTIC)
			if ((slop_bgn_size != *dmasize) ||
					(slop_end_size != *dmasize)) {
				panic("%s: confused alignment calculation\n"
						"\tslop_bgn_size %d\n\tslop_end_size %d\n\tdmasize %d",
						sc->sc_dev.dv_xname,slop_bgn_size,slop_end_size,*dmasize);
			}
#endif
			slop_end_size = 0;
		}

		if (slop_bgn_size+slop_end_size < *dmasize) {
			int error;
			error = bus_dmamap_load(esc->sc_scsi_dma.nd_dmat,
					esc->sc_dmamap,
					*addr+slop_bgn_size,
					*dmasize-(slop_bgn_size+slop_end_size),
					NULL, BUS_DMA_NOWAIT);
			if (error) {
				panic("%s: can't load dma map. error = %d",
						sc->sc_dev.dv_xname, error);
			}

		} else {
			/* If there's no DMA, then coalesce the fifo buffers */
			slop_bgn_size += slop_end_size;
			slop_end_size = 0;
		}

		esc->sc_slop_bgn_addr = *addr;
		esc->sc_slop_bgn_size = slop_bgn_size;
		esc->sc_slop_end_addr = (*addr+*dmasize)-slop_end_size;
		esc->sc_slop_end_size = slop_end_size;
	}

	esc->sc_datain = datain;

	return (0);
}

void
esp_dma_go(sc)
	struct ncr53c9x_softc *sc;
{
	struct esp_softc *esc = (struct esp_softc *)sc;

	DPRINTF(("esp_dma_go(datain = %d)\n",esc->sc_datain));

	DPRINTF(("\tbgn slop = %d\n\tend slop = %d\n\tmapsize = %d\n",
			esc->sc_slop_bgn_size,esc->sc_slop_end_size,
			esc->sc_dmamap->dm_mapsize));

	DPRINTF(("esp fifo size = %d\n",
			(NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)));

	if (esc->sc_datain) {
		NCR_WRITE_REG(sc, ESP_DCTL,
				ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMARD);
	} else {
		NCR_WRITE_REG(sc, ESP_DCTL,
				ESPDCTL_20MHZ | ESPDCTL_INTENB);
	}

	if (esc->sc_datain) {
		int i;
#ifdef DIAGNOSTIC
#if 0  /* This is a fine thing to happen */
		int n = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF);
		if (n != esc->sc_slop_bgn_size) {
			panic("%s: Unexpected data in fifo n = %d, expecting %d ",
					sc->sc_dev.dv_xname, n, esc->sc_slop_bgn_size);
		}
#endif
#endif
		for(i=0;i<esc->sc_slop_bgn_size;i++) {
			esc->sc_slop_bgn_addr[i]=NCR_READ_REG(sc, NCR_FIFO);
		}

	} else {
		int i;
		for(i=0;i<esc->sc_slop_bgn_size;i++) {
			NCR_WRITE_REG(sc, NCR_FIFO, esc->sc_slop_bgn_addr[i]);
		}

		DPRINTF(("esp fifo size = %d\n",
				(NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)));
	}

	if (esc->sc_dmamap->dm_mapsize != 0) {
		if (esc->sc_datain) {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMAMOD | ESPDCTL_DMARD);
		} else {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMAMOD);
		}


		nextdma_start(&esc->sc_scsi_dma,
				(esc->sc_datain ? DMACSR_READ : DMACSR_WRITE));
	} else {
#if defined(DIAGNOSTIC)
		/* verify that end slop is 0, since the shutdown
		 * callback will not be called.
		 */
		if (esc->sc_slop_end_size != 0) {
			panic("%s: Unexpected end slop with no DMA, slop = %d",
					sc->sc_dev.dv_xname, esc->sc_slop_end_size);
		}
#endif
#if 0
		if (esc->sc_datain) {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMARD | ESPDCTL_FLUSH);
		} else {
			NCR_WRITE_REG(sc, ESP_DCTL, ESPDCTL_20MHZ | ESPDCTL_INTENB);
			NCR_WRITE_REG(sc, ESP_DCTL, ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_FLUSH);
			NCR_WRITE_REG(sc, ESP_DCTL, ESPDCTL_20MHZ | ESPDCTL_INTENB);
		}
#endif

		esc->sc_datain = -1;
		esc->sc_slop_bgn_addr = 0;
		esc->sc_slop_bgn_size = 0;
		esc->sc_slop_end_addr = 0;
		esc->sc_slop_end_size = 0;

		DPRINTF(("esp fifo size = %d\n",
				(NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)));
	}
}

void
esp_dma_stop(sc)
	struct ncr53c9x_softc *sc;
{
	panic("Not yet implemented");
}

int
esp_dma_isactive(sc)
	struct ncr53c9x_softc *sc;
{
	struct esp_softc *esc = (struct esp_softc *)sc;
	return(	!nextdma_finished(&esc->sc_scsi_dma));
}

/****************************************************************/

/* Internal dma callback routines */
bus_dmamap_t
esp_dmacb_continue(arg)
	void *arg;
{
	struct ncr53c9x_softc *sc = (struct ncr53c9x_softc *)arg;
	struct esp_softc *esc = (struct esp_softc *)sc;

	DPRINTF(("esp dma continue\n"));

  bus_dmamap_sync(esc->sc_scsi_dma.nd_dmat, esc->sc_dmamap,
			0, esc->sc_dmamap->dm_mapsize,
			(esc->sc_datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE));

#ifdef DIAGNOSTIC
	if ((esc->sc_datain < 0) || (esc->sc_datain > 1)) {
		panic("%s: map not loaded in dma continue callback, datain = %d",
				sc->sc_dev.dv_xname,esc->sc_datain);
	}
#endif

	return(esc->sc_dmamap);
}

void
esp_dmacb_completed(map, arg)
	bus_dmamap_t map;
	void *arg;
{
	struct ncr53c9x_softc *sc = (struct ncr53c9x_softc *)arg;
	struct esp_softc *esc = (struct esp_softc *)sc;

	DPRINTF(("esp dma completed\n"));

#ifdef DIAGNOSTIC
	if ((esc->sc_datain < 0) || (esc->sc_datain > 1)) {
		panic("%s: map not loaded in dma completed callback, datain = %d",
				sc->sc_dev.dv_xname,esc->sc_datain);
	}
	if (map != esc->sc_dmamap) {
		panic("%s: unexpected tx completed map", sc->sc_dev.dv_xname);
	}
#endif

	/* @@@ Flush the fifo? */

  bus_dmamap_sync(esc->sc_scsi_dma.nd_dmat, esc->sc_dmamap,
			0, esc->sc_dmamap->dm_mapsize,
			(esc->sc_datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE));
}

void
esp_dmacb_shutdown(arg)
	void *arg;
{
	struct ncr53c9x_softc *sc = (struct ncr53c9x_softc *)arg;
	struct esp_softc *esc = (struct esp_softc *)sc;

	DPRINTF(("esp dma shutdown\n"));

#ifdef DIAGNOSTIC
	if ((esc->sc_datain < 0) || (esc->sc_datain > 1)) {
		panic("%s: map not loaded in dma shutdown callback, datain = %d",
				sc->sc_dev.dv_xname,esc->sc_datain);
	}
#endif

	bus_dmamap_unload(esc->sc_scsi_dma.nd_dmat, esc->sc_dmamap);

	/* Stuff the end slop into fifo */

	{
		if (esc->sc_datain) {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB | ESPDCTL_DMARD);
		} else {
			NCR_WRITE_REG(sc, ESP_DCTL,
					ESPDCTL_20MHZ | ESPDCTL_INTENB);
		}

		if (esc->sc_datain) {
			int i;
#ifdef DIAGNOSTIC
			int n = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF);
			if (n != esc->sc_slop_end_size) {
				panic("%s: Unexpected data in fifo n = %d, expecting %d at end",
						sc->sc_dev.dv_xname, n, esc->sc_slop_end_size);
			}
#endif
			for(i=0;i<esc->sc_slop_end_size;i++) {
				esc->sc_slop_end_addr[i]=NCR_READ_REG(sc, NCR_FIFO);
			}

		} else {
			int i;
			for(i=0;i<esc->sc_slop_end_size;i++) {
				NCR_WRITE_REG(sc, NCR_FIFO, esc->sc_slop_end_addr[i]);
			}
		}
	}


	esc->sc_datain = -1;
	esc->sc_slop_bgn_addr = 0;
	esc->sc_slop_bgn_size = 0;
	esc->sc_slop_end_addr = 0;
	esc->sc_slop_end_size = 0;
}