xref: /netbsd-src/sys/arch/arc/dti/btl.c (revision 8ff6f65dafc58186614d149001c905dec4c934a2)

/*	$NetBSD: btl.c,v 1.31 2023/12/20 06:36:02 thorpej Exp $	*/
/*	NetBSD: bt.c,v 1.10 1996/05/12 23:51:54 mycroft Exp 	*/

#undef BTDIAG
#define integrate

#define notyet /* XXX - #undef this, if this driver does actually work */

/*
 * Copyright (c) 1994, 1996 Charles M. Hannum.  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 Charles M. Hannum.
 * 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.
 */

/*
 * Originally written by Julian Elischer (julian@tfs.com)
 * for TRW Financial Systems for use under the MACH(2.5) operating system.
 *
 * TRW Financial Systems, in accordance with their agreement with Carnegie
 * Mellon University, makes this software available to CMU to distribute
 * or use in any manner that they see fit as long as this message is kept with
 * the software. For this reason TFS also grants any other persons or
 * organisations permission to use or modify this software.
 *
 * TFS supplies this software to be publicly redistributed
 * on the understanding that TFS is not responsible for the correct
 * functioning of this software in any circumstances.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: btl.c,v 1.31 2023/12/20 06:36:02 thorpej Exp $");

#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 <machine/intr.h>
#include <machine/pio.h>

#include <arc/dti/desktech.h>

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

#include <dev/isa/isavar.h>
#include <arc/dti/btlreg.h>
#include <arc/dti/btlvar.h>

#ifndef DDB
#define Debugger() panic("should call debugger here (bt742a.c)")
#endif /* ! DDB */

/*
 * Mail box defs  etc.
 * these could be bigger but we need the bt_softc to fit on a single page..
 */
#define BT_MBX_SIZE	32	/* mail box size  (MAX 255 MBxs) */
				/* don't need that many really */
#define BT_CCB_MAX	32	/* store up to 32 CCBs at one time */
#define	CCB_HASH_SIZE	32	/* hash table size for phystokv */
#define	CCB_HASH_SHIFT	9
#define CCB_HASH(x)	((((long)(x))>>CCB_HASH_SHIFT) & (CCB_HASH_SIZE - 1))

#define bt_nextmbx(wmb, mbx, mbio) \
	if ((wmb) == &(mbx)->mbio[BT_MBX_SIZE - 1])	\
		(wmb) = &(mbx)->mbio[0];		\
	else						\
		(wmb)++;

struct bt_mbx {
	struct bt_mbx_out mbo[BT_MBX_SIZE];
	struct bt_mbx_in mbi[BT_MBX_SIZE];
	struct bt_mbx_out *cmbo;	/* Collection Mail Box out */
	struct bt_mbx_out *tmbo;	/* Target Mail Box out */
	struct bt_mbx_in *tmbi;		/* Target Mail Box in */
};

#define KVTOPHYS(x)	(*btl_conf->bc_kvtophys)((int)(x))
#define PHYSTOKV(x)	(*btl_conf->bc_phystokv)((int)(x))

struct bt_softc {
	device_t sc_dev;
	void *sc_ih;

	int sc_iobase;
	int sc_irq, sc_drq;

	char sc_model[7],
	     sc_firmware[6];

	struct bt_mbx *sc_mbx;		/* all our mailboxes */
#define	wmbx	(sc->sc_mbx)
	struct bt_ccb *sc_ccbhash[CCB_HASH_SIZE];
	TAILQ_HEAD(, bt_ccb) sc_free_ccb, sc_waiting_ccb;
	TAILQ_HEAD(, bt_buf) sc_free_buf;
	int sc_numccbs, sc_mbofull;
	int sc_numbufs;
	int sc_scsi_dev;		/* adapters scsi id */
	struct scsipi_link sc_link;	/* prototype for devs */
	struct scsipi_adapter sc_adapter;
};

#ifdef BTDEBUG
int     bt_debug = 0;
#endif /* BTDEBUG */

int bt_cmd(int, struct bt_softc *, int, u_char *, int, u_char *);
integrate void bt_finish_ccbs(struct bt_softc *);
int btintr(void *);
integrate void bt_reset_ccb(struct bt_softc *, struct bt_ccb *);
void bt_free_ccb(struct bt_softc *, struct bt_ccb *);
integrate void bt_init_ccb(struct bt_softc *, struct bt_ccb *);
struct bt_ccb *bt_get_ccb(struct bt_softc *, int);
struct bt_ccb *bt_ccb_phys_kv(struct bt_softc *, u_long);
void bt_queue_ccb(struct bt_softc *, struct bt_ccb *);
void bt_collect_mbo(struct bt_softc *);
void bt_start_ccbs(struct bt_softc *);
void bt_done(struct bt_softc *, struct bt_ccb *);
int bt_find(struct isa_attach_args *, struct bt_softc *);
void bt_init(struct bt_softc *);
void bt_inquire_setup_information(struct bt_softc *);
void btminphys(struct buf *);
int bt_scsi_cmd(struct scsipi_xfer *);
int bt_poll(struct bt_softc *, struct scsipi_xfer *, int);
void bt_timeout(void *arg);
void bt_free_buf(struct bt_softc *, struct bt_buf *);
struct bt_buf * bt_get_buf(struct bt_softc *, int);

/* the below structure is so we have a default dev struct for out link struct */
struct scsipi_device bt_dev = {
	NULL,			/* Use default error handler */
	NULL,			/* have a queue, served by this */
	NULL,			/* have no async handler */
	NULL,			/* Use default 'done' routine */
};

static int	btprobe(device_t, cfdata_t, void *);
static void	btattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(btl, sizeof(struct bt_softc),
    btprobe, btattach, NULL, NULL);

#define BT_RESET_TIMEOUT	2000	/* time to wait for reset (mSec) */
#define	BT_ABORT_TIMEOUT	2000	/* time to wait for abort (mSec) */

struct btl_config *btl_conf = NULL;

/*
 * bt_cmd(iobase, sc, icnt, ibuf, ocnt, obuf)
 *
 * Activate Adapter command
 *    icnt:   number of args (outbound bytes including opcode)
 *    ibuf:   argument buffer
 *    ocnt:   number of expected returned bytes
 *    obuf:   result buffer
 *    wait:   number of seconds to wait for response
 *
 * Performs an adapter command through the ports.  Not to be confused with a
 * scsi command, which is read in via the DMA; one of the adapter commands
 * tells it to read in a scsi command.
 */
int
bt_cmd(int iobase, struct bt_softc *sc, int icnt, int ocnt, u_char *ibuf,
    u_char *obuf)
{
	const char *name;
	int i;
	int wait;
	u_char sts;
	u_char opcode = ibuf[0];

	if (sc != NULL)
		name = device_xname(sc->sc_dev);
	else
		name = "(bt probe)";

	/*
	 * Calculate a reasonable timeout for the command.
	 */
	switch (opcode) {
	case BT_INQUIRE_DEVICES:
		wait = 15 * 20000;
		break;
	default:
		wait = 1 * 20000;
		break;
	}

	/*
	 * Wait for the adapter to go idle, unless it's one of
	 * the commands which don't need this
	 */
	if (opcode != BT_MBO_INTR_EN) {
		for (i = 20000; i; i--) {	/* 1 sec? */
			sts = isa_inb(iobase + BT_STAT_PORT);
			if (sts & BT_STAT_IDLE)
				break;
			delay(50);
		}
		if (!i) {
			printf("%s: bt_cmd, host not idle(0x%x)\n",
			    name, sts);
			return ENXIO;
		}
	}
	/*
	 * Now that it is idle, if we expect output, preflush the
	 * queue feeding to us.
	 */
	if (ocnt) {
		while ((isa_inb(iobase + BT_STAT_PORT)) & BT_STAT_DF)
			isa_inb(iobase + BT_DATA_PORT);
	}
	/*
	 * Output the command and the number of arguments given
	 * for each byte, first check the port is empty.
	 */
	while (icnt--) {
		for (i = wait; i; i--) {
			sts = isa_inb(iobase + BT_STAT_PORT);
			if (!(sts & BT_STAT_CDF))
				break;
			delay(50);
		}
		if (!i) {
			if (opcode != BT_INQUIRE_REVISION &&
			    opcode != BT_INQUIRE_REVISION_3)
				printf("%s: bt_cmd, cmd/data port full\n", name);
			isa_outb(iobase + BT_CTRL_PORT, BT_CTRL_SRST);
			return ENXIO;
		}
		isa_outb(iobase + BT_CMD_PORT, *ibuf++);
	}
	/*
	 * If we expect input, loop that many times, each time,
	 * looking for the data register to have valid data
	 */
	while (ocnt--) {
		for (i = wait; i; i--) {
			sts = isa_inb(iobase + BT_STAT_PORT);
			if (sts & BT_STAT_DF)
				break;
			delay(50);
		}
		if (!i) {
			if (opcode != BT_INQUIRE_REVISION &&
			    opcode != BT_INQUIRE_REVISION_3)
				printf("%s: bt_cmd, cmd/data port empty %d\n",
				    name, ocnt);
			isa_outb(iobase + BT_CTRL_PORT, BT_CTRL_SRST);
			return ENXIO;
		}
		*obuf++ = isa_inb(iobase + BT_DATA_PORT);
	}
	/*
	 * Wait for the board to report a finished instruction.
	 * We may get an extra interrupt for the HACC signal, but this is
	 * unimportant.
	 */
	if (opcode != BT_MBO_INTR_EN) {
		for (i = 20000; i; i--) {	/* 1 sec? */
			sts = isa_inb(iobase + BT_INTR_PORT);
			/* XXX Need to save this in the interrupt handler? */
			if (sts & BT_INTR_HACC)
				break;
			delay(50);
		}
		if (!i) {
			printf("%s: bt_cmd, host not finished(0x%x)\n",
			    name, sts);
			return ENXIO;
		}
	}
	isa_outb(iobase + BT_CTRL_PORT, BT_CTRL_IRST);
	return 0;
}

/*
 * Check if the device can be found at the port given
 * and if so, set it up ready for further work
 * as an argument, takes the isa_device structure from
 * autoconf.c
 */
static int
btprobe(device_t parent, cfdata_t cf, void *aux)
{
	struct isa_attach_args *ia = aux;

#ifdef NEWCONFIG
	if (ia->ia_iobase == IOBASEUNK)
		return 0;
#endif

	if (btl_conf == NULL)
		return (0);

	/* See if there is a unit at this location. */
	if (bt_find(ia, NULL) != 0)
		return 0;

	ia->ia_msize = 0;
	ia->ia_iosize = 4;
	/* IRQ and DRQ set by bt_find(). */
	return 1;
}

/*
 * Attach all the sub-devices we can find
 */
static void
btattach(device_t parent, device_t self, void *aux)
{
	struct isa_attach_args *ia = aux;
	struct bt_softc *sc = device_private(self);
	struct bt_ccb *ccb;
	struct bt_buf *buf;
	u_int bouncearea;
	u_int bouncebase;
	u_int bouncesize;

	sc->sc_dev = self;

	if (bt_find(ia, sc) != 0)
		panic("btattach: bt_find of %s failed", device_xname(self));
	sc->sc_iobase = ia->ia_iobase;

	/*
	 * create mbox area
	 */
	(*btl_conf->bc_bouncemem)(&bouncebase, &bouncesize);
	bouncearea = bouncebase + sizeof(struct bt_mbx);
	sc->sc_mbx = (struct bt_mbx *)bouncebase;

	bt_inquire_setup_information(sc);
	bt_init(sc);
	TAILQ_INIT(&sc->sc_free_ccb);
	TAILQ_INIT(&sc->sc_free_buf);
	TAILQ_INIT(&sc->sc_waiting_ccb);

	/*
	 * fill up with ccb's
	 */
	while (sc->sc_numccbs < BT_CCB_MAX) {
		ccb = (struct bt_ccb *)bouncearea;
		bouncearea +=  sizeof(struct bt_ccb);
		bt_init_ccb(sc, ccb);
		TAILQ_INSERT_HEAD(&sc->sc_free_ccb, ccb, chain);
		sc->sc_numccbs++;
	}
	/*
	 * fill up with bufs's
	 */
	while ((bouncearea + sizeof(struct bt_buf)) < bouncebase + bouncesize) {
		buf = (struct bt_buf *)bouncearea;
		bouncearea +=  sizeof(struct bt_buf);
		TAILQ_INSERT_HEAD(&sc->sc_free_buf, buf, chain);
		sc->sc_numbufs++;
	}
	/*
	 * Fill in the adapter.
	 */
	sc->sc_adapter.scsipi_cmd = bt_scsi_cmd;
	sc->sc_adapter.scsipi_minphys = btminphys;
	/*
	 * fill in the prototype scsipi_link.
	 */
	sc->sc_link.scsipi_scsi.channel = SCSI_CHANNEL_ONLY_ONE;
	sc->sc_link.adapter_softc = sc;
	sc->sc_link.scsipi_scsi.adapter_target = sc->sc_scsi_dev;
	sc->sc_link.adapter = &sc->sc_adapter;
	sc->sc_link.device = &bt_dev;
	sc->sc_link.openings = 1;
	sc->sc_link.scsipi_scsi.max_target = 7;
	sc->sc_link.scsipi_scsi.max_lun = 7;
	sc->sc_link.type = BUS_SCSI;

	sc->sc_ih = isa_intr_establish(ia->ia_ic, sc->sc_irq, IST_EDGE,
	    IPL_BIO, btintr, sc);

	/*
	 * ask the adapter what subunits are present
	 */
	config_found(self, &sc->sc_link, scsiprint, CFARGS_NONE);
}

integrate void
bt_finish_ccbs(struct bt_softc *sc)
{
	struct bt_mbx_in *wmbi;
	struct bt_ccb *ccb;
	int i;

	wmbi = wmbx->tmbi;

	if (wmbi->stat == BT_MBI_FREE) {
		for (i = 0; i < BT_MBX_SIZE; i++) {
			if (wmbi->stat != BT_MBI_FREE) {
				printf("%s: mbi not in round-robin order\n",
				    device_xname(sc->sc_dev));
				goto AGAIN;
			}
			bt_nextmbx(wmbi, wmbx, mbi);
		}
#ifdef BTDIAGnot
		printf("%s: mbi interrupt with no full mailboxes\n",
		    device_xname(sc->sc_dev));
#endif
		return;
	}

AGAIN:
	do {
		ccb = bt_ccb_phys_kv(sc, phystol(wmbi->ccb_addr));
		if (!ccb) {
			printf("%s: bad mbi ccb pointer; skipping\n",
			    device_xname(sc->sc_dev));
			goto next;
		}

#ifdef BTDEBUG
		if (bt_debug) {
			u_char *cp = (u_char *) &ccb->scsi_cmd;
			printf("op=%x %x %x %x %x %x\n",
			    cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
			printf("stat %x for mbi addr = 0x%08x, ",
			    wmbi->stat, wmbi);
			printf("ccb addr = 0x%x\n", ccb);
		}
#endif /* BTDEBUG */

		switch (wmbi->stat) {
		case BT_MBI_OK:
		case BT_MBI_ERROR:
			if ((ccb->flags & CCB_ABORT) != 0) {
				/*
				 * If we already started an abort, wait for it
				 * to complete before clearing the CCB.  We
				 * could instead just clear CCB_SENDING, but
				 * what if the mailbox was already received?
				 * The worst that happens here is that we clear
				 * the CCB a bit later than we need to.  BFD.
				 */
				goto next;
			}
			break;

		case BT_MBI_ABORT:
		case BT_MBI_UNKNOWN:
			/*
			 * Even if the CCB wasn't found, we clear it anyway.
			 * See preceding comment.
			 */
			break;

		default:
			printf("%s: bad mbi status %02x; skipping\n",
			    device_xname(sc->sc_dev), wmbi->stat);
			goto next;
		}

		callout_stop(&ccb->xs->xs_callout);
		bt_done(sc, ccb);

	next:
		wmbi->stat = BT_MBI_FREE;
		bt_nextmbx(wmbi, wmbx, mbi);
	} while (wmbi->stat != BT_MBI_FREE);

	wmbx->tmbi = wmbi;
}

/*
 * Catch an interrupt from the adaptor
 */
int
btintr(void *arg)
{
	struct bt_softc *sc = arg;
	int iobase = sc->sc_iobase;
	u_char sts;

#ifdef BTDEBUG
	printf("%s: btintr ", device_xname(sc->sc_dev));
#endif /* BTDEBUG */

	/*
	 * First acknowledge the interrupt, Then if it's not telling about
	 * a completed operation just return.
	 */
	sts = isa_inb(iobase + BT_INTR_PORT);
	if ((sts & BT_INTR_ANYINTR) == 0)
		return 0;
	isa_outb(iobase + BT_CTRL_PORT, BT_CTRL_IRST);

#ifdef BTDIAG
	/* Make sure we clear CCB_SENDING before finishing a CCB. */
	bt_collect_mbo(sc);
#endif

	/* Mail box out empty? */
	if (sts & BT_INTR_MBOA) {
		struct bt_toggle toggle;

		toggle.cmd.opcode = BT_MBO_INTR_EN;
		toggle.cmd.enable = 0;
		bt_cmd(iobase, sc, sizeof(toggle.cmd), (u_char *)&toggle.cmd, 0,
		    (u_char *)0);
		bt_start_ccbs(sc);
	}

	/* Mail box in full? */
	if (sts & BT_INTR_MBIF)
		bt_finish_ccbs(sc);

	return 1;
}

integrate void
bt_reset_ccb(struct bt_softc *sc, struct bt_ccb *ccb)
{

	ccb->flags = 0;
}

/*
 * A ccb is put onto the free list.
 */
void
bt_free_ccb(struct bt_softc *sc, struct bt_ccb *ccb)
{
	int s;

	s = splbio();

	bt_reset_ccb(sc, ccb);
	TAILQ_INSERT_HEAD(&sc->sc_free_ccb, ccb, chain);

	/*
	 * If there were none, wake anybody waiting for one to come free,
	 * starting with queued entries.
	 */
	if (ccb->chain.tqe_next == 0)
		wakeup(&sc->sc_free_ccb);

	splx(s);
}

/*
 * A buf is put onto the free list.
 */
void
bt_free_buf(struct bt_softc *sc, struct bt_buf *buf)
{
	int s;

	s = splbio();

	TAILQ_INSERT_HEAD(&sc->sc_free_buf, buf, chain);
	sc->sc_numbufs++;

	/*
	 * If there were none, wake anybody waiting for one to come free,
	 * starting with queued entries.
	 */
	if (buf->chain.tqe_next == 0)
		wakeup(&sc->sc_free_buf);

	splx(s);
}

integrate void
bt_init_ccb(struct bt_softc *sc, struct bt_ccb *ccb)
{
	int hashnum;

	memset(ccb, 0, sizeof(struct bt_ccb));
	/*
	 * put in the phystokv hash table
	 * Never gets taken out.
	 */
	ccb->hashkey = KVTOPHYS(ccb);
	hashnum = CCB_HASH(ccb->hashkey);
	ccb->nexthash = sc->sc_ccbhash[hashnum];
	sc->sc_ccbhash[hashnum] = ccb;
	bt_reset_ccb(sc, ccb);
}

/*
 * Get a free ccb
 *
 * If there are none, either return an error or sleep.
 */
struct bt_ccb *
bt_get_ccb(struct bt_softc *sc, int nosleep)
{
	struct bt_ccb *ccb;
	int s;

	s = splbio();

	/*
	 * If we can and have to, sleep waiting for one to come free.
	 */
	for (;;) {
		ccb = sc->sc_free_ccb.tqh_first;
		if (ccb) {
			TAILQ_REMOVE(&sc->sc_free_ccb, ccb, chain);
			break;
		}
		if (nosleep)
			goto out;
		tsleep(&sc->sc_free_ccb, PRIBIO, "btccb", 0);
	}

	ccb->flags |= CCB_ALLOC;

out:
	splx(s);
	return ccb;
}

/*
 * Get a free buf
 *
 * If there are none, either return an error or sleep.
 */
struct bt_buf *
bt_get_buf(struct bt_softc *sc, int nosleep)
{
	struct bt_buf *buf;
	int s;

	s = splbio();

	/*
	 * If we can and have to, sleep waiting for one to come free.
	 */
	for (;;) {
		buf = sc->sc_free_buf.tqh_first;
		if (buf) {
			TAILQ_REMOVE(&sc->sc_free_buf, buf, chain);
			sc->sc_numbufs--;
			break;
		}
		if (nosleep)
			goto out;
		tsleep(&sc->sc_free_buf, PRIBIO, "btbuf", 0);
	}

out:
	splx(s);
	return buf;
}

/*
 * Given a physical address, find the ccb that it corresponds to.
 */
struct bt_ccb *
bt_ccb_phys_kv(struct bt_softc *sc, u_long ccb_phys)
{
	int hashnum = CCB_HASH(ccb_phys);
	struct bt_ccb *ccb = sc->sc_ccbhash[hashnum];

	while (ccb) {
		if (ccb->hashkey == ccb_phys)
			break;
		ccb = ccb->nexthash;
	}
	return ccb;
}

/*
 * Queue a CCB to be sent to the controller, and send it if possible.
 */
void
bt_queue_ccb(struct bt_softc *sc, struct bt_ccb *ccb)
{

	TAILQ_INSERT_TAIL(&sc->sc_waiting_ccb, ccb, chain);
	bt_start_ccbs(sc);
}

/*
 * Garbage collect mailboxes that are no longer in use.
 */
void
bt_collect_mbo(struct bt_softc *sc)
{
	struct bt_mbx_out *wmbo;	/* Mail Box Out pointer */

	wmbo = wmbx->cmbo;

	while (sc->sc_mbofull > 0) {
		if (wmbo->cmd != BT_MBO_FREE)
			break;

#ifdef BTDIAG
		ccb = bt_ccb_phys_kv(sc, phystol(wmbo->ccb_addr));
		ccb->flags &= ~CCB_SENDING;
#endif

		--sc->sc_mbofull;
		bt_nextmbx(wmbo, wmbx, mbo);
	}

	wmbx->cmbo = wmbo;
}

/*
 * Send as many CCBs as we have empty mailboxes for.
 */
void
bt_start_ccbs(struct bt_softc *sc)
{
	int iobase = sc->sc_iobase;
	struct bt_mbx_out *wmbo;	/* Mail Box Out pointer */
	struct bt_ccb *ccb;

	wmbo = wmbx->tmbo;

	while ((ccb = sc->sc_waiting_ccb.tqh_first) != NULL) {
		if (sc->sc_mbofull >= BT_MBX_SIZE) {
			bt_collect_mbo(sc);
			if (sc->sc_mbofull >= BT_MBX_SIZE) {
				struct bt_toggle toggle;

				toggle.cmd.opcode = BT_MBO_INTR_EN;
				toggle.cmd.enable = 1;
				bt_cmd(iobase, sc, sizeof(toggle.cmd),
				    (u_char *)&toggle.cmd, 0, (u_char *)0);
				break;
			}
		}

		TAILQ_REMOVE(&sc->sc_waiting_ccb, ccb, chain);
#ifdef BTDIAG
		ccb->flags |= CCB_SENDING;
#endif

		/* Link ccb to mbo. */
		ltophys(KVTOPHYS(ccb), wmbo->ccb_addr);
		if (ccb->flags & CCB_ABORT)
			wmbo->cmd = BT_MBO_ABORT;
		else
			wmbo->cmd = BT_MBO_START;

		/* Tell the card to poll immediately. */
		isa_outb(iobase + BT_CMD_PORT, BT_START_SCSI);

		if ((ccb->xs->xs_control & XS_CTL_POLL) == 0)
			callout_reset(&ccb->xs->xs_callout,
			    mstohz(ccb->timeout), bt_timeout, ccb);

		++sc->sc_mbofull;
		bt_nextmbx(wmbo, wmbx, mbo);
	}

	wmbx->tmbo = wmbo;
}

/*
 * We have a ccb which has been processed by the
 * adaptor, now we look to see how the operation
 * went. Wake up the owner if waiting
 */
void
bt_done(struct bt_softc *sc, struct bt_ccb *ccb)
{
	struct scsi_sense_data *s1, *s2;
	struct scsipi_xfer *xs = ccb->xs;

	u_long thiskv, thisbounce;
	int bytes_this_page, datalen;
	struct bt_scat_gath *sg;
	int seg;

	SC_DEBUG(xs->sc_link, SDEV_DB2, ("bt_done\n"));
	/*
	 * Otherwise, put the results of the operation
	 * into the xfer and call whoever started it
	 */
#ifdef BTDIAG
	if (ccb->flags & CCB_SENDING) {
		printf("%s: exiting ccb still in transit!\n",
		    device_xname(sc->sc_dev));
		Debugger();
		return;
	}
#endif
	if ((ccb->flags & CCB_ALLOC) == 0) {
		printf("%s: exiting ccb not allocated!\n",
		    device_xname(sc->sc_dev));
		Debugger();
		return;
	}
	if (xs->error == XS_NOERROR) {
		if (ccb->host_stat != BT_OK) {
			switch (ccb->host_stat) {
			case BT_SEL_TIMEOUT:	/* No response */
				xs->error = XS_SELTIMEOUT;
				break;
			default:	/* Other scsi protocol messes */
				printf("%s: host_stat %x\n",
				    device_xname(sc->sc_dev), ccb->host_stat);
				xs->error = XS_DRIVER_STUFFUP;
				break;
			}
		} else if (ccb->target_stat != SCSI_OK) {
			switch (ccb->target_stat) {
			case SCSI_CHECK:
				s1 = &ccb->scsi_sense;
				s2 = &xs->sense.scsi_sense;
				*s2 = *s1;
				xs->error = XS_SENSE;
				break;
			case SCSI_BUSY:
				xs->error = XS_BUSY;
				break;
			default:
				printf("%s: target_stat %x\n",
				    device_xname(sc->sc_dev), ccb->target_stat);
				xs->error = XS_DRIVER_STUFFUP;
				break;
			}
		} else
			xs->resid = 0;
	}

	if((datalen = xs->datalen) != 0) {
		thiskv = (int)xs->data;
		sg = ccb->scat_gath;
		seg = phystol(ccb->data_length) / sizeof(struct bt_scat_gath);

		while (seg) {
			thisbounce = PHYSTOKV(phystol(sg->seg_addr));
			bytes_this_page = phystol(sg->seg_len);
			if(xs->xs_control & XS_CTL_DATA_IN) {
				memcpy((void *)thiskv, (void *)thisbounce, bytes_this_page);
			}
			bt_free_buf(sc, (struct bt_buf *)thisbounce);
			thiskv += bytes_this_page;
			datalen -= bytes_this_page;

			sg++;
			seg--;
		}
	}

	bt_free_ccb(sc, ccb);
	xs->xs_status |= XS_STS_DONE;
	scsipi_done(xs);
}

/*
 * Find the board and find its irq/drq
 */
int
bt_find(struct isa_attach_args *ia, struct bt_softc *sc)
{
	int iobase = ia->ia_iobase;
	int i;
	u_char sts;
	struct bt_extended_inquire inquire;
	struct bt_config config;
	int irq, drq;

#ifndef notyet
	/* Check something is at the ports we need to access */
	sts = isa_inb(iobase + BHA_STAT_PORT);
	if (sts == 0xFF)
		return (0);
#endif

	/*
	 * reset board, If it doesn't respond, assume
	 * that it's not there.. good for the probe
	 */

	isa_outb(iobase + BT_CTRL_PORT, BT_CTRL_HRST | BT_CTRL_SRST);

	delay(100);
	for (i = BT_RESET_TIMEOUT; i; i--) {
		sts = isa_inb(iobase + BT_STAT_PORT);
		if (sts == (BT_STAT_IDLE | BT_STAT_INIT))
			break;
		delay(1000);
	}
	if (!i) {
#ifdef BTDEBUG
		if (bt_debug)
			printf("bt_find: No answer from buslogic board\n");
#endif /* BTDEBUG */
		return 1;
	}

#ifndef notyet
	/*
	 * The BusLogic cards implement an Adaptec 1542 (aha)-compatible
	 * interface. The native bha interface is not compatible with
	 * an aha. 1542. We need to ensure that we never match an
	 * Adaptec 1542. We must also avoid sending Adaptec-compatible
	 * commands to a real bha, lest it go into 1542 emulation mode.
	 * (On an indirect bus like ISA, we should always probe for BusLogic
	 * interfaces before Adaptec interfaces).
	 */

	/*
	 * Make sure we don't match an AHA-1542A or AHA-1542B, by checking
	 * for an extended-geometry register.  The 1542[AB] don't have one.
	 */
	sts = isa_inb(iobase +  BT_EXTGEOM_PORT);
	if (sts == 0xFF)
		return (0);
#endif /* notyet */

	/*
	 * Check that we actually know how to use this board.
	 */
	delay(1000);
	memset(&inquire, 0, sizeof inquire);
	inquire.cmd.opcode = BT_INQUIRE_EXTENDED;
	inquire.cmd.len = sizeof(inquire.reply);
	i = bt_cmd(iobase, sc, sizeof(inquire.cmd), (u_char *)&inquire.cmd,
	    sizeof(inquire.reply), (u_char *)&inquire.reply);

#ifndef notyet
	/*
	 * Some 1542Cs (CP, perhaps not CF, may depend on firmware rev)
	 * have the extended-geometry register and also respond to
	 * BHA_INQUIRE_EXTENDED.  Make sure we never match such cards,
	 * by checking the size of the reply is what a BusLogic card returns.
	 */
	if (i) { /* XXX - this doesn't really check the size. ??? see bha.c */
#ifdef BTDEBUG
		printf("bt_find: board returned %d instead of %d to %s\n",
		       i, sizeof(inquire.reply), "INQUIRE_EXTENDED");
#endif
		return (0);
	}

	/* OK, we know we've found a buslogic adaptor. */
#endif /* notyet */

	switch (inquire.reply.bus_type) {
	case BT_BUS_TYPE_24BIT:
	case BT_BUS_TYPE_32BIT:
		break;
	case BT_BUS_TYPE_MCA:
		/* We don't grok MicroChannel (yet). */
		return 1;
	default:
		printf("bt_find: illegal bus type %c\n", inquire.reply.bus_type);
		return 1;
	}

	/*
	 * Assume we have a board at this stage setup DMA channel from
	 * jumpers and save int level
	 */
	delay(1000);
	config.cmd.opcode = BT_INQUIRE_CONFIG;
	bt_cmd(iobase, sc, sizeof(config.cmd), (u_char *)&config.cmd,
	    sizeof(config.reply), (u_char *)&config.reply);
	switch (config.reply.chan) {
	case EISADMA:
		drq = DRQUNK;
		break;
	case CHAN0:
		drq = 0;
		break;
	case CHAN5:
		drq = 5;
		break;
	case CHAN6:
		drq = 6;
		break;
	case CHAN7:
		drq = 7;
		break;
	default:
		printf("bt_find: illegal drq setting %x\n", config.reply.chan);
		return 1;
	}

	switch (config.reply.intr) {
	case INT9:
		irq = 9;
		break;
	case INT10:
		irq = 10;
		break;
	case INT11:
		irq = 11;
		break;
	case INT12:
		irq = 12;
		break;
	case INT14:
		irq = 14;
		break;
	case INT15:
		irq = 15;
		break;
	default:
		printf("bt_find: illegal irq setting %x\n", config.reply.intr);
		return 1;
	}

	if (sc != NULL) {
		/* who are we on the scsi bus? */
		sc->sc_scsi_dev = config.reply.scsi_dev;

		sc->sc_iobase = iobase;
		sc->sc_irq = irq;
		sc->sc_drq = drq;
	} else {
		if (ia->ia_irq == IRQUNK)
			ia->ia_irq = irq;
		else if (ia->ia_irq != irq)
			return 1;
		if (ia->ia_drq == DRQUNK)
			ia->ia_drq = drq;
		else if (ia->ia_drq != drq)
			return 1;
	}

	return 0;
}

/*
 * Start the board, ready for normal operation
 */
void
bt_init(struct bt_softc *sc)
{
	int iobase = sc->sc_iobase;
	struct bt_devices devices;
	struct bt_setup setup;
	struct bt_mailbox mailbox;
	struct bt_period period;
	int i;

	/* Enable round-robin scheme - appeared at firmware rev. 3.31. */
	if (strcmp(sc->sc_firmware, "3.31") >= 0) {
		struct bt_toggle toggle;

		toggle.cmd.opcode = BT_ROUND_ROBIN;
		toggle.cmd.enable = 1;
		bt_cmd(iobase, sc, sizeof(toggle.cmd), (u_char *)&toggle.cmd,
		    0, (u_char *)0);
	}

	/* Inquire Installed Devices (to force synchronous negotiation). */
	devices.cmd.opcode = BT_INQUIRE_DEVICES;
	bt_cmd(iobase, sc, sizeof(devices.cmd), (u_char *)&devices.cmd,
	    sizeof(devices.reply), (u_char *)&devices.reply);

	/* Obtain setup information from. */
	setup.cmd.opcode = BT_INQUIRE_SETUP;
	setup.cmd.len = sizeof(setup.reply);
	bt_cmd(iobase, sc, sizeof(setup.cmd), (u_char *)&setup.cmd,
	    sizeof(setup.reply), (u_char *)&setup.reply);

	printf("%s: %s, %s\n",
	    device_xname(sc->sc_dev),
	    setup.reply.sync_neg ? "sync" : "async",
	    setup.reply.parity ? "parity" : "no parity");

	for (i = 0; i < 8; i++)
		period.reply.period[i] = setup.reply.sync[i].period * 5 + 20;

	if (sc->sc_firmware[0] >= '3') {
		period.cmd.opcode = BT_INQUIRE_PERIOD;
		period.cmd.len = sizeof(period.reply);
		bt_cmd(iobase, sc, sizeof(period.cmd), (u_char *)&period.cmd,
		    sizeof(period.reply), (u_char *)&period.reply);
	}

	for (i = 0; i < 8; i++) {
		if (!setup.reply.sync[i].valid ||
		    (!setup.reply.sync[i].offset && !setup.reply.sync[i].period))
			continue;
		printf("%s targ %d: sync, offset %d, period %dnsec\n",
		    device_xname(sc->sc_dev), i,
		    setup.reply.sync[i].offset, period.reply.period[i] * 10);
	}

	/*
	 * Set up initial mail box for round-robin operation.
	 */
	for (i = 0; i < BT_MBX_SIZE; i++) {
		wmbx->mbo[i].cmd = BT_MBO_FREE;
		wmbx->mbi[i].stat = BT_MBI_FREE;
	}
	wmbx->cmbo = wmbx->tmbo = &wmbx->mbo[0];
	wmbx->tmbi = &wmbx->mbi[0];
	sc->sc_mbofull = 0;

	/* Initialize mail box. */
	mailbox.cmd.opcode = BT_MBX_INIT_EXTENDED;
	mailbox.cmd.nmbx = BT_MBX_SIZE;
	ltophys(KVTOPHYS(wmbx), mailbox.cmd.addr);
	bt_cmd(iobase, sc, sizeof(mailbox.cmd), (u_char *)&mailbox.cmd,
	    0, (u_char *)0);
}

void
bt_inquire_setup_information(struct bt_softc *sc)
{
	int iobase = sc->sc_iobase;
	struct bt_model model;
	struct bt_revision revision;
	struct bt_digit digit;
	char *p;

	/*
	 * Get the firmware revision.
	 */
	p = sc->sc_firmware;
	revision.cmd.opcode = BT_INQUIRE_REVISION;
	bt_cmd(iobase, sc, sizeof(revision.cmd), (u_char *)&revision.cmd,
	    sizeof(revision.reply), (u_char *)&revision.reply);
	*p++ = revision.reply.firm_revision;
	*p++ = '.';
	*p++ = revision.reply.firm_version;
	digit.cmd.opcode = BT_INQUIRE_REVISION_3;
	bt_cmd(iobase, sc, sizeof(digit.cmd), (u_char *)&digit.cmd,
	    sizeof(digit.reply), (u_char *)&digit.reply);
	*p++ = digit.reply.digit;
	if (revision.reply.firm_revision >= '3' ||
	    (revision.reply.firm_revision == '3' && revision.reply.firm_version >= '3')) {
		digit.cmd.opcode = BT_INQUIRE_REVISION_4;
		bt_cmd(iobase, sc, sizeof(digit.cmd), (u_char *)&digit.cmd,
		    sizeof(digit.reply), (u_char *)&digit.reply);
		*p++ = digit.reply.digit;
	}
	while (p > sc->sc_firmware && (p[-1] == ' ' || p[-1] == '\0'))
		p--;
	*p = '\0';

	/*
	 * Get the model number.
	 */
	if (revision.reply.firm_revision >= '3') {
		p = sc->sc_model;
		model.cmd.opcode = BT_INQUIRE_MODEL;
		model.cmd.len = sizeof(model.reply);
		bt_cmd(iobase, sc, sizeof(model.cmd), (u_char *)&model.cmd,
		    sizeof(model.reply), (u_char *)&model.reply);
		*p++ = model.reply.id[0];
		*p++ = model.reply.id[1];
		*p++ = model.reply.id[2];
		*p++ = model.reply.id[3];
		while (p > sc->sc_model && (p[-1] == ' ' || p[-1] == '\0'))
			p--;
		*p++ = model.reply.version[0];
		*p++ = model.reply.version[1];
		while (p > sc->sc_model && (p[-1] == ' ' || p[-1] == '\0'))
			p--;
		*p = '\0';
	} else
		strcpy(sc->sc_model, "542B");

	printf(": model BT-%s, firmware %s\n", sc->sc_model, sc->sc_firmware);
}

void
btminphys(struct buf *bp)
{

	if (bp->b_bcount > ((BT_NSEG - 1) << PGSHIFT))
		bp->b_bcount = ((BT_NSEG - 1) << PGSHIFT);
	minphys(bp);
}

/*
 * start a scsi operation given the command and the data address.  Also needs
 * the unit, target and lu.
 */
int
bt_scsi_cmd(struct scsipi_xfer *xs)
{
	struct scsipi_link *sc_link = xs->sc_link;
	struct bt_softc *sc = sc_link->adapter_softc;
	struct bt_ccb *ccb;
	struct bt_scat_gath *sg;
	int seg;		/* scatter gather seg being worked on */
	u_long thiskv, thisbounce;
	int bytes_this_page, datalen, control;
	int s;

	SC_DEBUG(sc_link, SDEV_DB2, ("bt_scsi_cmd\n"));
	/*
	 * get a ccb to use. If the transfer
	 * is from a buf (possibly from interrupt time)
	 * then we can't allow it to sleep
	 */
	control = xs->xs_control;
	if ((ccb = bt_get_ccb(sc, control & XS_CTL_NOSLEEP)) == NULL) {
		xs->error = XS_DRIVER_STUFFUP;
		return TRY_AGAIN_LATER;
	}
	ccb->xs = xs;
	ccb->timeout = xs->timeout;

	/*
	 * Put all the arguments for the xfer in the ccb
	 */
	if (control & XS_CTL_RESET) {
		ccb->opcode = BT_RESET_CCB;
		ccb->scsi_cmd_length = 0;
	} else {
		/* can't use S/G if zero length */
		if (xs->cmdlen > sizeof(ccb->scsi_cmd)) {
			printf("%s: cmdlen %d too large for CCB\n",
			    device_xname(sc->sc_dev), xs->cmdlen);
			xs->error = XS_DRIVER_STUFFUP;
			bt_free_ccb(sc, ccb);
			return COMPLETE;
		}
		ccb->opcode = (xs->datalen ? BT_INIT_SCAT_GATH_CCB
					   : BT_INITIATOR_CCB);
		memcpy(&ccb->scsi_cmd, xs->cmd,
		    ccb->scsi_cmd_length = xs->cmdlen);
	}

	if (xs->datalen) {
		sg = ccb->scat_gath;
		seg = 0;
		/*
		 * Set up the scatter-gather block.
		 */
		SC_DEBUG(sc_link, SDEV_DB4,
		    ("%d @0x%x:- ", xs->datalen, xs->data));

		datalen = xs->datalen;
		thiskv = (int)xs->data;

		while (datalen && seg < BT_NSEG) {

			/* put in the base address of a buf */
			thisbounce = (u_long)
				bt_get_buf(sc, control & XS_CTL_NOSLEEP);
			if(thisbounce == 0)
				break;
			ltophys(KVTOPHYS(thisbounce), sg->seg_addr);
			bytes_this_page = uimin(sizeof(struct bt_buf), datalen);
			if (control & XS_CTL_DATA_OUT) {
				memcpy((void *)thisbounce, (void *)thiskv, bytes_this_page);
			}
			thiskv += bytes_this_page;
			datalen -= bytes_this_page;

			ltophys(bytes_this_page, sg->seg_len);
			sg++;
			seg++;
		}
		SC_DEBUGN(sc_link, SDEV_DB4, ("\n"));
		if (datalen) {
			printf("%s: bt_scsi_cmd, out of bufs %d of %d left.\n",
			    device_xname(sc->sc_dev), datalen, xs->datalen);
			goto badbuf;
		}
		ltophys(KVTOPHYS(ccb->scat_gath), ccb->data_addr);
		ltophys(seg * sizeof(struct bt_scat_gath), ccb->data_length);
	} else {		/* No data xfer, use non S/G values */
		ltophys(0, ccb->data_addr);
		ltophys(0, ccb->data_length);
	}

	ccb->data_out = 0;
	ccb->data_in = 0;
	ccb->target = sc_link->scsipi_scsi.target;
	ccb->lun = sc_link->scsipi_scsi.lun;
	ltophys(KVTOPHYS(&ccb->scsi_sense), ccb->sense_ptr);
	ccb->req_sense_length = sizeof(ccb->scsi_sense);
	ccb->host_stat = 0x00;
	ccb->target_stat = 0x00;
	ccb->link_id = 0;
	ltophys(0, ccb->link_addr);

	s = splbio();
	bt_queue_ccb(sc, ccb);
	splx(s);

	/*
	 * Usually return SUCCESSFULLY QUEUED
	 */
	SC_DEBUG(sc_link, SDEV_DB3, ("cmd_sent\n"));
	if ((control & XS_CTL_POLL) == 0)
		return SUCCESSFULLY_QUEUED;

	/*
	 * If we can't use interrupts, poll on completion
	 */
	if (bt_poll(sc, xs, ccb->timeout)) {
		bt_timeout(ccb);
		if (bt_poll(sc, xs, ccb->timeout))
			bt_timeout(ccb);
	}
	return COMPLETE;

badbuf:
	sg = ccb->scat_gath;
	while (seg) {
		thisbounce = PHYSTOKV(phystol(sg->seg_addr));
		bt_free_buf(sc, (struct bt_buf *)thisbounce);
		sg++;
		seg--;
	}
	xs->error = XS_DRIVER_STUFFUP;
	bt_free_ccb(sc, ccb);
	return TRY_AGAIN_LATER;
}

/*
 * Poll a particular unit, looking for a particular xs
 */
int
bt_poll(struct bt_softc *sc, struct scsipi_xfer *xs, int count)
{
	int iobase = sc->sc_iobase;

	/* timeouts are in msec, so we loop in 1000 usec cycles */
	while (count) {
		/*
		 * If we had interrupts enabled, would we
		 * have got an interrupt?
		 */
		if (isa_inb(iobase + BT_INTR_PORT) & BT_INTR_ANYINTR)
			btintr(sc);
		if (xs->xs_status & XS_STS_DONE)
			return 0;
		delay(1000);	/* only happens in boot so ok */
		count--;
	}
	return 1;
}

void
bt_timeout(void *arg)
{
	struct bt_ccb *ccb = arg;
	struct scsipi_xfer *xs = ccb->xs;
	struct scsipi_link *sc_link = xs->sc_link;
	struct bt_softc *sc = sc_link->adapter_softc;
	int s;

	scsi_print_addr(sc_link);
	printf("timed out");

	s = splbio();

#ifdef BTDIAG
	/*
	 * If the ccb's mbx is not free, then the board has gone Far East?
	 */
	bt_collect_mbo(sc);
	if (ccb->flags & CCB_SENDING) {
		printf("%s: not taking commands!\n", device_xname(sc->sc_dev));
		Debugger();
	}
#endif

	/*
	 * If it has been through before, then
	 * a previous abort has failed, don't
	 * try abort again
	 */
	if (ccb->flags & CCB_ABORT) {
		/* abort timed out */
		printf(" AGAIN\n");
		/* XXX Must reset! */
	} else {
		/* abort the operation that has timed out */
		printf("\n");
		ccb->xs->error = XS_TIMEOUT;
		ccb->timeout = BT_ABORT_TIMEOUT;
		ccb->flags |= CCB_ABORT;
		bt_queue_ccb(sc, ccb);
	}

	splx(s);
}