NetBSD/sys/arch/sun3/dev/si.c

/*	$NetBSD: si.c,v 1.21 1995/08/14 20:00:00 gwr Exp $	*/

/*
 * Copyright (C) 1994 Adam Glass, Gordon W. Ross
 * Copyright (C) 1993	Allen K. Briggs, Chris P. Caputo,
 *			Michael L. Finch, Bradley A. Grantham, and
 *			Lawrence A. Kesteloot
 * 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 the Alice Group.
 * 4. The names of the Alice Group or any of its members may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE ALICE GROUP ``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 ALICE GROUP 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.
 */

#define DEBUG 1

/* XXX - Need to add support for real DMA. -gwr */
/* #define PSEUDO_DMA 1 (broken) */

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

#include <machine/autoconf.h>
#include <machine/isr.h>
#include <machine/obio.h>

#include <scsi/scsi_all.h>
#include <scsi/scsi_debug.h>
#include <scsi/scsiconf.h>

#include "scsi_defs.h"
#include "scsi_5380.h"
#include "scsi_sunsi.h"

#ifdef	DEBUG
static int si_debug = 0;
static int si_flags = 0 /* | SDEV_DB2 */ ;
#endif

#define SCI_PHASE_DISC		0	/* sort of ... */
#define SCI_CLR_INTR(regs)	((volatile)(regs->sci_iack))
#define SCI_ACK(ptr,phase)	(ptr)->sci_tcmd = (phase)
#define SCSI_TIMEOUT_VAL	1000000
#define WAIT_FOR_NOT_REQ(ptr) {	\
	int scsi_timeout = SCSI_TIMEOUT_VAL; \
	while ( ((ptr)->sci_bus_csr & SCI_BUS_REQ) && \
		 ((ptr)->sci_bus_csr & SCI_BUS_REQ) && \
		 ((ptr)->sci_bus_csr & SCI_BUS_REQ) && \
		 (--scsi_timeout) ); \
	if (!scsi_timeout) { \
		printf("scsi timeout--WAIT_FOR_NOT_REQ---%s, line %d.\n", \
			__FILE__, __LINE__); \
		goto scsi_timeout_error; \
	} \
	}
#define WAIT_FOR_REQ(ptr) {	\
	int scsi_timeout = SCSI_TIMEOUT_VAL; \
	while ( (((ptr)->sci_bus_csr & SCI_BUS_REQ) == 0) && \
		(((ptr)->sci_bus_csr & SCI_BUS_REQ) == 0) && \
		(((ptr)->sci_bus_csr & SCI_BUS_REQ) == 0) && \
		 (--scsi_timeout) ); \
	if (!scsi_timeout) { \
		printf("scsi timeout--WAIT_FOR_REQ---%s, line %d.\n", \
			__FILE__, __LINE__); \
		goto scsi_timeout_error; \
	} \
	}
#define WAIT_FOR_BSY(ptr) {	\
	int scsi_timeout = SCSI_TIMEOUT_VAL; \
	while ( (((ptr)->sci_bus_csr & SCI_BUS_BSY) == 0) && \
		(((ptr)->sci_bus_csr & SCI_BUS_BSY) == 0) && \
		(((ptr)->sci_bus_csr & SCI_BUS_BSY) == 0) && \
		 (--scsi_timeout) ); \
	if (!scsi_timeout) { \
		printf("scsi timeout--WAIT_FOR_BSY---%s, line %d.\n", \
			__FILE__, __LINE__); \
		goto scsi_timeout_error; \
	} \
	}

#define ARBITRATION_RETRIES 1000

#ifdef DDB
int Debugger();
#else
#define Debugger() panic("Should call Debugger here %s:%d", \
			 __FILE__, __LINE__)
#endif

struct ncr5380_softc {
    struct device sc_dev;
    volatile void *sc_regs;
    int sc_adapter_type;
    int sc_adapter_iv_am;	/* int. vec + address modifier */
    struct scsi_link sc_link;
};

static void		ncr5380_minphys(struct buf *bp);
static int		ncr5380_scsi_cmd(struct scsi_xfer *xs);
static int		ncr5380_reset_adapter(struct ncr5380_softc *);
static int		ncr5380_reset_scsibus(struct ncr5380_softc *);
static int		ncr5380_poll(int adapter, int timeout);
static int		ncr5380_send_cmd(struct scsi_xfer *xs);

static int		ncr_intr(void *);

static int	si_generic(int adapter, int id, int lun,
			 struct scsi_generic *cmd, int cmdlen,
			 void *databuf, int datalen);
static int	si_group0(int adapter, int id, int lun,
			    int opcode, int addr, int len,
			    int flags, caddr_t databuf, int datalen);

static char scsi_name[] = "si";

struct scsi_adapter	ncr5380_switch = {
	ncr5380_scsi_cmd,		/* scsi_cmd()		*/
	ncr5380_minphys,		/* scsi_minphys()	*/
	NULL,				/* open_target_lu()	*/
	NULL,				/* close_target_lu()	*/
};

/* This is copied from julian's bt driver */
/* "so we have a default dev struct for our link struct." */
struct scsi_device ncr_dev = {
	NULL,		/* Use default error handler.	    */
	NULL,		/* Use default start handler.		*/
	NULL,		/* Use default async handler.	    */
	NULL,		/* Use default "done" routine.	    */
};

static int	si_match();
static void	si_attach();

struct cfdriver sicd = {
	NULL, "si", si_match, si_attach, DV_DULL,
	sizeof(struct ncr5380_softc), NULL, 0,
};

static int
si_print(aux, name)
	void *aux;
	char *name;
{
}

static int
si_match(parent, vcf, args)
	struct device	*parent;
	void		*vcf, *args;
{
	struct cfdata	*cf = vcf;
	struct confargs *ca = args;
	int x, probe_addr;

	/* Default interrupt priority always splbio==2 */
	if (ca->ca_intpri == -1)
		ca->ca_intpri = 2;

	if ((cpu_machine_id == SUN3_MACH_50) ||
	    (cpu_machine_id == SUN3_MACH_60) )
	{
		/* Sun3/50 or Sun3/60 have only OBIO "si" */
		if (ca->ca_bustype != BUS_OBIO)
			return(0);
		if (ca->ca_paddr == -1)
			ca->ca_paddr = OBIO_NCR_SCSI;
		/* OK... */
	} else {
		/* Other Sun3 models may have VME "si" or "sc" */
		if (ca->ca_bustype != BUS_VME16)
			return (0);
		if (ca->ca_paddr == -1)
			return (0);
		/* OK... */
	}

	/* Make sure there is something there... */
	x = bus_peek(ca->ca_bustype, ca->ca_paddr + 1, 1);
	if (x == -1)
		return (0);

	/*
	 * If this is a VME SCSI board, we have to determine whether
	 * it is an "sc" (Sun2) or "si" (Sun3) SCSI board.  This can
	 * be determined using the fact that the "sc" board occupies
	 * 4K bytes in VME space but the "si" board occupies 2K bytes.
	 */
	if (ca->ca_bustype == BUS_VME16) {
		/* Note, the "si" board should NOT respond here. */
		x = bus_peek(ca->ca_bustype, ca->ca_paddr + 0x801, 1);
		if (x != -1)
			return(0);
	}

    return (1);
}

static void
si_attach(parent, self, args)
	struct device	*parent, *self;
	void		*args;
{
	struct ncr5380_softc *ncr5380 = (struct ncr5380_softc *) self;
	volatile sci_regmap_t *regs;
	struct confargs *ca = args;

	switch (ca->ca_bustype) {

	case BUS_OBIO:
		regs = (sci_regmap_t *)
			obio_alloc(ca->ca_paddr, sizeof(*regs));
		isr_add_autovect(ncr_intr, (void *)ncr5380,
						 ca->ca_intpri);
		break;

	case BUS_VME16:
		regs = (sci_regmap_t *)
			bus_mapin(ca->ca_bustype, ca->ca_paddr, sizeof(*regs));
		isr_add_vectored(ncr_intr, (void *)ncr5380,
						 ca->ca_intpri, ca->ca_intvec);
		break;

	default:
		printf("unknown\n");
		return;
	}

	ncr5380->sc_adapter_type = ca->ca_bustype;
	ncr5380->sc_adapter_iv_am =
		VME_SUPV_DATA_24 | (ca->ca_intvec & 0xFF);
	ncr5380->sc_regs = regs;

	/*
	 * fill in the prototype scsi_link.
	 */
    ncr5380->sc_link.adapter_softc = ncr5380;
    ncr5380->sc_link.adapter_target = 7;
    ncr5380->sc_link.adapter = &ncr5380_switch;
    ncr5380->sc_link.device = &ncr_dev;
    ncr5380->sc_link.openings = 2;
#ifdef	DEBUG
    ncr5380->sc_link.flags |= si_flags;
#endif

    printf("\n");
	ncr5380_reset_adapter(ncr5380);
	ncr5380_reset_scsibus(ncr5380);
	config_found(self, &(ncr5380->sc_link), si_print);
}

#define MIN_PHYS	65536	/*BARF!!!!*/
static void
ncr5380_minphys(struct buf *bp)
{
	if (bp->b_bcount > MIN_PHYS) {
		printf("Uh-oh...  ncr5380_minphys setting bp->b_bcount = %x.\n", MIN_PHYS);
		bp->b_bcount = MIN_PHYS;
	}
	minphys(bp);
}
#undef MIN_PHYS

static int
ncr5380_scsi_cmd(struct scsi_xfer *xs)
{
	int flags, s, r;

	flags = xs->flags;
	if (xs->bp) flags |= (SCSI_NOSLEEP);
	if ( flags & ITSDONE ) {
		printf("Already done?");
		xs->flags &= ~ITSDONE;
	}
	if ( ! ( flags & INUSE ) ) {
		printf("Not in use?");
		xs->flags |= INUSE;
	}

	s = splbio();

	if ( flags & SCSI_RESET ) {
		printf("flags & SCSIRESET.\n");
		ncr5380_reset_scsibus(xs->sc_link->adapter_softc);
		r = COMPLETE;
	} else {
		r = ncr5380_send_cmd(xs);
		xs->flags |= ITSDONE;
		scsi_done(xs);
	}

	splx(s);

	switch(r) {
	case COMPLETE:
	case SUCCESSFULLY_QUEUED:
		r = SUCCESSFULLY_QUEUED;
		if (xs->flags & SCSI_POLL)
			r = COMPLETE;
		break;
	default:
		break;
	}
	return r;
}

#ifdef	DEBUG
static int
ncr5380_show_scsi_cmd(struct scsi_xfer *xs)
{
	u_char	*b = (u_char *) xs->cmd;
	int	i  = 0;

	if ( ! ( xs->flags & SCSI_RESET ) ) {
		printf("si(%d:%d:%d)-",
			   xs->sc_link->scsibus,
			   xs->sc_link->target,
			   xs->sc_link->lun);
		while (i < xs->cmdlen) {
			if (i) printf(",");
			printf("%x",b[i++]);
		}
		printf("-\n");
	} else {
		printf("si(%d:%d:%d)-RESET-\n",
			   xs->sc_link->scsibus,
			   xs->sc_link->target,
			   xs->sc_link->lun);
	}
}
#endif

/*
 * Actual chip control.
 */

static void
ncr_sbc_intr(struct ncr5380_softc *ncr5380)
{
	volatile sci_regmap_t *regs = ncr5380->sc_regs;

	if ((regs->sci_csr & SCI_CSR_INT) == 0) {
#ifdef	DEBUG
		printf (" ncr_sbc_intr: spurrious\n");
#endif
		return;
	}

	SCI_CLR_INTR(regs);
#ifdef	DEBUG
	printf (" ncr_sbc_intr\n");
#endif
}

static void
ncr_dma_intr(struct ncr5380_softc *ncr5380)
{
	volatile struct si_regs *regs = ncr5380->sc_regs;

#ifdef	DEBUG
	printf (" ncr_dma_intr\n");
#endif
}

static int
ncr_intr(void *arg)
{
	struct ncr5380_softc *ncr5380 = arg;
	volatile struct si_regs *si = ncr5380->sc_regs;
	int rv = 0;

	/* Interrupts not enabled?  Can not be for us. */
	if ((si->si_csr & SI_CSR_INTR_EN) == 0)
		return rv;

	if (si->si_csr & SI_CSR_DMA_IP) {
		ncr_dma_intr(ncr5380);
		rv++;
	}
	if (si->si_csr & SI_CSR_SBC_IP) {
		ncr_sbc_intr(ncr5380);
		rv++;
	}
	return rv;
}

static int
ncr5380_reset_adapter(struct ncr5380_softc *sc)
{
	volatile struct si_regs *si = sc->sc_regs;

#ifdef	DEBUG
	if (si_debug) {
		printf("si_reset_adapter\n");
	}
#endif

	/* The reset bits in the CSR are active low. */
	si->si_csr = 0;
	delay(20);
	si->si_csr = SI_CSR_FIFO_RES | SI_CSR_SCSI_RES;
	si->fifo_count = 0;
	if (sc->sc_adapter_type == BUS_VME16) {
		si->dma_addrh = 0;
		si->dma_addrl = 0;
		si->dma_counth = 0;
		si->dma_countl = 0;
		si->iv_am = sc->sc_adapter_iv_am;
	}
}

static int
ncr5380_reset_scsibus(struct ncr5380_softc *ncr5380)
{
	volatile sci_regmap_t *regs = ncr5380->sc_regs;

#ifdef	DEBUG
	if (si_debug) {
		printf("si_reset_scsibus\n");
	}
#endif

	regs->sci_icmd = SCI_ICMD_RST;
	delay(100);
	regs->sci_icmd = 0;

	regs->sci_mode = 0;
	regs->sci_tcmd = SCI_PHASE_DISC;
	regs->sci_sel_enb = 0;

	SCI_CLR_INTR(regs);
	/* XXX - Need long delay here! */
}

static int
ncr5380_poll(int adapter, int timeout)
{
}

static int
ncr5380_send_cmd(struct scsi_xfer *xs)
{
	int	sense;

#ifdef	DIAGNOSTIC
	if ((getsr() & PSL_IPL) < PSL_IPL2)
		panic("ncr_send_cmd: bad spl");
#endif

#ifdef	DEBUG
	if (si_debug & 2)
		ncr5380_show_scsi_cmd(xs);
#endif

	sense = si_generic( xs->sc_link->scsibus, xs->sc_link->target,
			  xs->sc_link->lun, xs->cmd, xs->cmdlen,
			  xs->data, xs->datalen );

	switch (sense) {
	case 0:	/* success */
		xs->resid = 0;
		xs->error = XS_NOERROR;
		break;

	case 0x02:	/* Check condition */
#ifdef	DEBUG
		if (si_debug)
			printf("check cond. target %d.\n",
				   xs->sc_link->target);
#endif
		delay(10);	/* Phil's fix for slow devices. */
		si_group0(xs->sc_link->scsibus,
				  xs->sc_link->target,
				  xs->sc_link->lun,
				  0x3, 0x0,
				  sizeof(struct scsi_sense_data),
				  0, (caddr_t) &(xs->sense),
				  sizeof(struct scsi_sense_data));
		xs->error = XS_SENSE;
		break;
	case 0x08:	/* Busy - common code will delay, retry. */
		xs->error = XS_BUSY;
		break;
	default:	/* Dead - tell common code to give up. */
		xs->error = XS_DRIVER_STUFFUP;
		break;

	}
	return (COMPLETE);
}

static int
si_select_target(register volatile sci_regmap_t *regs,
	      u_char myid, u_char tid, int with_atn)
{
	register u_char	bid, icmd;
	int		ret = SCSI_RET_RETRY;
	int 	arb_retries, arb_wait;

	/* for our purposes.. */
	myid = 1 << myid;
	tid = 1 << tid;

	regs->sci_sel_enb = 0; /* we don't want any interrupts. */
	regs->sci_tcmd = 0;	/* get into a harmless state */

	arb_retries = ARBITRATION_RETRIES;

retry_arbitration:
	regs->sci_mode = 0;	/* get into a harmless state */
wait_for_bus_free:
	if (--arb_retries <= 0) {
#ifdef	DEBUG
		if (si_debug) {
			printf("si_select: arb_retries expended; resetting...\n");
		}
#endif
		ret = SCSI_RET_NEED_RESET;
		goto nosel;
	}

	icmd = regs->sci_icmd & ~(SCI_ICMD_DIFF|SCI_ICMD_TEST);

	if (regs->sci_bus_csr & (SCI_BUS_BSY|SCI_BUS_SEL)) {
		/* Something is sitting on the SCSI bus... */
#ifdef	DEBUG
		/* Only complain once (the last time through). */
		if (si_debug && (arb_retries <= 1)) {
			printf("si_select_target: still BSY+SEL\n");
		}
#endif
		/* Give it a little time, then try again. */
		delay(10);
		goto wait_for_bus_free;
	}

	regs->sci_odata = myid;
	regs->sci_mode = SCI_MODE_ARB;
/*	regs->sci_mode |= SCI_MODE_ARB;	XXX? */

	/* AIP might not set if BSY went true after we checked */
	/* Wait up to about 100 usec. for it to appear. */
	arb_wait = 50;	/* X2 */
	do {
		if (regs->sci_icmd & SCI_ICMD_AIP)
			goto got_aip;
		delay2us();
	} while (--arb_wait > 0);
	/* XXX - Could have missed it? */
#ifdef	DEBUG
	if (si_debug)
		printf("si_select_target: API did not appear\n");
#endif
	goto retry_arbitration;

	got_aip:
#ifdef	DEBUG
	if (si_debug & 4) {
		printf("si_select_target: API after %d tries (last wait %d)\n",
			   ARBITRATION_RETRIES - arb_retries,
			   (50 - arb_wait));
	}
#endif

	delay(3);	/* 2.2 uSec. arbitration delay */

	if (regs->sci_icmd & SCI_ICMD_LST) {
#ifdef	DEBUG
		if (si_debug)
			printf ("lost 1\n");
#endif
		goto retry_arbitration;	/* XXX */
	}

	regs->sci_mode &= ~SCI_MODE_PAR_CHK;
	bid = regs->sci_data;

	if ((bid & ~myid) > myid) {
#ifdef	DEBUG
		if (si_debug)
			printf ("lost 2\n");
#endif
		/* Trying again will not help. */
		goto lost;
	}
	if (regs->sci_icmd & SCI_ICMD_LST) {
#ifdef	DEBUG
		if (si_debug)
			printf ("lost 3\n");
#endif
		goto lost;
	}

	/* Won arbitration, enter selection phase now */
	icmd = regs->sci_icmd & ~(SCI_ICMD_DIFF|SCI_ICMD_TEST);
	icmd |= (with_atn ? (SCI_ICMD_SEL|SCI_ICMD_ATN) : SCI_ICMD_SEL);
	regs->sci_icmd = icmd;

	if (regs->sci_icmd & SCI_ICMD_LST) {
#ifdef	DEBUG
		if (si_debug)
			printf ("nosel\n");
#endif
		goto nosel;
	}

	/* XXX a target that violates specs might still drive the bus XXX */
	/* XXX should put our id out, and after the delay check nothi XXX */
	/* XXX ng else is out there.				      XXX */

	delay2us();

	regs->sci_sel_enb = 0;

	regs->sci_odata = myid | tid;

	icmd |= SCI_ICMD_BSY|SCI_ICMD_DATA;
	regs->sci_icmd = icmd;

/*	regs->sci_mode &= ~SCI_MODE_ARB;	 2 deskew delays, too */
	regs->sci_mode = 0;			/* 2 deskew delays, too */

	icmd &= ~SCI_ICMD_BSY;
	regs->sci_icmd = icmd;

	/* bus settle delay, 400ns */
	delay2us(); /* too much (was 2) ? */

	regs->sci_mode |= SCI_MODE_PAR_CHK;

	{
		register int timeo  = 2500;/* 250 msecs in 100 usecs chunks */
		while ((regs->sci_bus_csr & SCI_BUS_BSY) == 0) {
			if (--timeo > 0) {
				delay(100);
			} else {
				/* This is the "normal" no-such-device select error. */
#ifdef	DEBUG
				if (si_debug)
					printf("si_select: not BSY (nothing there)\n");
#endif
				goto nodev;
			}
		}
	}

	icmd &= ~(SCI_ICMD_DATA|SCI_ICMD_SEL);
	regs->sci_icmd = icmd;
/*	regs->sci_sel_enb = myid;*/	/* looks like we should NOT have it */
	/* XXX - SCI_MODE_PAR_CHK ? */
	return SCSI_RET_SUCCESS;

nodev:
	ret = SCSI_RET_DEVICE_DOWN;
	regs->sci_sel_enb = myid;
nosel:
	regs->sci_icmd = 0;
	regs->sci_mode = 0;
	return ret;

lost:
	regs->sci_icmd = 0;
	regs->sci_mode = 0;
#ifdef	DEBUG
	if (si_debug) {
		printf("si_select: lost arbitration\n");
	}
#endif
	return ret;
}

sci_data_out(regs, phase, count, data)
	register volatile sci_regmap_t	*regs;
	unsigned char		*data;
{
	register unsigned char	icmd;
	register int		cnt=0;

	/* ..checks.. */

	icmd = regs->sci_icmd & ~(SCI_ICMD_DIFF|SCI_ICMD_TEST);
loop:
	/* SCSI bus phase not valid until REQ is true. */
	WAIT_FOR_REQ(regs);
	if (SCI_CUR_PHASE(regs->sci_bus_csr) != phase)
		return cnt;

	icmd |= SCI_ICMD_DATA;
	regs->sci_icmd = icmd;
	regs->sci_odata = *data++;
	icmd |= SCI_ICMD_ACK;
	regs->sci_icmd = icmd;

	icmd &= ~(SCI_ICMD_DATA|SCI_ICMD_ACK);
	WAIT_FOR_NOT_REQ(regs);
	regs->sci_icmd = icmd;
	++cnt;
	if (--count > 0)
		goto loop;
scsi_timeout_error:
	return cnt;
}

sci_data_in(regs, phase, count, data)
	register volatile sci_regmap_t	*regs;
	unsigned char		*data;
{
	register unsigned char	icmd;
	register int		cnt=0;

	/* ..checks.. */

	icmd = regs->sci_icmd & ~(SCI_ICMD_DIFF|SCI_ICMD_TEST);

loop:
	/* SCSI bus phase not valid until REQ is true. */
	WAIT_FOR_REQ(regs);
	if (SCI_CUR_PHASE(regs->sci_bus_csr) != phase)
		return cnt;

	*data++ = regs->sci_data;
	icmd |= SCI_ICMD_ACK;
	regs->sci_icmd = icmd;

	icmd &= ~SCI_ICMD_ACK;
	WAIT_FOR_NOT_REQ(regs);
	regs->sci_icmd = icmd;
	++cnt;
	if (--count > 0)
		goto loop;

scsi_timeout_error:
	return cnt;
}

/* Return -1 (error) or number of bytes sent (>=0). */
static int
si_command_transfer(register volatile sci_regmap_t *regs,
		 int maxlen, u_char *data, u_char *status, u_char *msg)
{
	int	xfer, phase;

	xfer = 0;
	regs->sci_icmd = 0;

	while (1) {

		WAIT_FOR_REQ(regs);

		phase = SCI_CUR_PHASE(regs->sci_bus_csr);

		switch (phase) {
			case SCSI_PHASE_CMD:
				SCI_ACK(regs,SCSI_PHASE_CMD);
				xfer += sci_data_out(regs, SCSI_PHASE_CMD,
						   	maxlen, data);
				goto out;

			case SCSI_PHASE_DATA_IN:
				printf("command_transfer: Data in phase?\n");
				goto err;

			case SCSI_PHASE_DATA_OUT:
				printf("command_transfer: Data out phase?\n");
				goto err;

			case SCSI_PHASE_STATUS:
				SCI_ACK(regs,SCSI_PHASE_STATUS);
				printf("command_transfer: status in...\n");
				sci_data_in(regs, SCSI_PHASE_STATUS,
					  	1, status);
				printf("command_transfer: status=0x%x\n", *status);
				goto err;

			case SCSI_PHASE_MESSAGE_IN:
				SCI_ACK(regs,SCSI_PHASE_MESSAGE_IN);
				printf("command_transfer: msg in?\n");
				sci_data_in(regs, SCSI_PHASE_MESSAGE_IN,
					  	1, msg);
				break;

			case SCSI_PHASE_MESSAGE_OUT:
				SCI_ACK(regs,SCSI_PHASE_MESSAGE_OUT);
				sci_data_out(regs, SCSI_PHASE_MESSAGE_OUT,
					  	1, msg);
				break;

			default:
				printf("command_transfer: Unexpected phase 0x%x\n", phase);
				goto err;
		}
	}
scsi_timeout_error:
 err:
	xfer = -1;
 out:
	return xfer;
}

static int
si_data_transfer(register volatile sci_regmap_t *regs,
	      int maxlen, u_char *data, u_char *status, u_char *msg)
{
	int	retlen = 0, xfer, phase;

	regs->sci_icmd = 0;

	*status = 0;

	while (1) {

		WAIT_FOR_REQ(regs);

		phase = SCI_CUR_PHASE(regs->sci_bus_csr);

		switch (phase) {
			case SCSI_PHASE_CMD:
				printf("Command phase in data_transfer().\n");
				return retlen;
			case SCSI_PHASE_DATA_IN:
				SCI_ACK(regs,SCSI_PHASE_DATA_IN);
#if PSEUDO_DMA
				xfer = sci_pdma_in(regs, SCSI_PHASE_DATA_IN,
						  	maxlen, data);
#else
				xfer = sci_data_in(regs, SCSI_PHASE_DATA_IN,
						  	maxlen, data);
#endif
				retlen += xfer;
				maxlen -= xfer;
				break;
			case SCSI_PHASE_DATA_OUT:
				SCI_ACK(regs,SCSI_PHASE_DATA_OUT);
#if PSEUDO_DMA
				xfer = sci_pdma_out(regs, SCSI_PHASE_DATA_OUT,
						   	maxlen, data);
#else
				xfer = sci_data_out(regs, SCSI_PHASE_DATA_OUT,
						   	maxlen, data);
#endif
				retlen += xfer;
				maxlen -= xfer;
				break;
			case SCSI_PHASE_STATUS:
				SCI_ACK(regs,SCSI_PHASE_STATUS);
				sci_data_in(regs, SCSI_PHASE_STATUS,
					  	1, status);
				break;
			case SCSI_PHASE_MESSAGE_IN:
				SCI_ACK(regs,SCSI_PHASE_MESSAGE_IN);
				sci_data_in(regs, SCSI_PHASE_MESSAGE_IN,
					  	1, msg);
				if (*msg == 0) {
					return retlen;
				} else {
					printf( "message 0x%x in "
						"data_transfer.\n", *msg);
				}
				break;
			case SCSI_PHASE_MESSAGE_OUT:
				SCI_ACK(regs,SCSI_PHASE_MESSAGE_OUT);
				sci_data_out(regs, SCSI_PHASE_MESSAGE_OUT,
					  	1, msg);
				break;
			default:
				printf( "Unexpected phase 0x%x in "
					"data_transfer().\n", phase);
scsi_timeout_error:
				return retlen;
				break;
		}
	}
}

static int
si_dorequest(struct ncr5380_softc *sc,
	int target, int lun, u_char *cmd, int cmdlen,
	char *databuf, int datalen, int *sent)
	/* Returns 0 on success, -1 on internal error, or the status byte */
{
	register volatile sci_regmap_t *regs = sc->sc_regs;
	int	cmd_bytes_sent, r;
	u_char	stat, msg, c;

#ifdef	DEBUG
	if (si_debug) {
		printf("si_dorequest: target=%d, lun=%d\n", target, lun);
	}
#endif

	*sent = 0;

	if ( ( r = si_select_target(regs, 7, target, 1) ) != SCSI_RET_SUCCESS) {
#ifdef	DEBUG
		if (si_debug) {
			printf("si_dorequest: select returned %d\n", r);
		}
#endif

		SCI_CLR_INTR(regs);
		switch (r) {

		case SCSI_RET_NEED_RESET:
			printf("si_dorequest: target=%d, lun=%d, resetting...\n",
				   target, lun, r);
			ncr5380_reset_adapter(sc);
			ncr5380_reset_scsibus(sc);
			/* fall through */
		case SCSI_RET_RETRY:
			return 0x08;	/* Busy - tell common code to retry. */

		default:
			printf("si_dorequest: target=%d, lun=%d, error=%d.\n",
				target, lun, r);
			/* fall through */
		case SCSI_RET_DEVICE_DOWN:
			return -1;	/* Dead - tell common code to give up. */
		}
	}

	c = 0x80 | lun;

	if ((cmd_bytes_sent = si_command_transfer(regs, cmdlen,
				(u_char *) cmd, &stat, &c)) != cmdlen)
	{
		SCI_CLR_INTR(regs);
		if (cmd_bytes_sent >= 0) {
			printf("Data underrun sending CCB (%d bytes of %d, sent).\n",
				   cmd_bytes_sent, cmdlen);
		}
		return -1;
	}

	*sent = si_data_transfer(regs, datalen, (u_char *)databuf,
				  &stat, &msg);
#ifdef	DEBUG
	if (si_debug) {
		printf("si_dorequest: data transfered = %d\n", *sent);
	}
#endif

	return stat;
}

static int
si_generic(int adapter, int id, int lun, struct scsi_generic *cmd,
  	 int cmdlen, void *databuf, int datalen)
{
	register struct ncr5380_softc *sc = sicd.cd_devs[adapter];
	int i, j, sent;

	if (cmd->opcode == TEST_UNIT_READY)	/* XXX */
		cmd->bytes[0] = ((u_char) lun << 5);

	i = si_dorequest(sc, id, lun, (u_char *) cmd, cmdlen,
					 databuf, datalen, &sent);

	return i;
}

static int
si_group0(int adapter, int id, int lun, int opcode, int addr, int len,
		int flags, caddr_t databuf, int datalen)
{
	register struct ncr5380_softc *sc = sicd.cd_devs[adapter];
	unsigned char cmd[6];
	int i, j, sent;

	cmd[0] = opcode;		/* Operation code           		*/
	cmd[1] = (lun << 5) | ((addr >> 16) & 0x1F);	/* Lun & MSB of addr	*/
	cmd[2] = (addr >> 8) & 0xFF;	/* addr					*/
	cmd[3] = addr & 0xFF;		/* LSB of addr				*/
	cmd[4] = len;			/* Allocation length			*/
	cmd[5] = flags;		/* Link/Flag				*/

	i = si_dorequest(sc, id, lun, cmd, 6, databuf, datalen, &sent);

	return i;
}