path: root/sys/arch/pica/dev/asc.c

/*	$NetBSD: asc.c,v 1.10 1994/12/05 19:11:12 dean Exp $	*/

/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell and Rick Macklem.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)asc.c	8.3 (Berkeley) 7/3/94
 */

/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

/*
 * HISTORY
 * Log:	scsi_53C94_hdw.c,v
 * Revision 2.5  91/02/05  17:45:07  mrt
 * 	Added author notices
 * 	[91/02/04  11:18:43  mrt]
 * 
 * 	Changed to use new Mach copyright
 * 	[91/02/02  12:17:20  mrt]
 * 
 * Revision 2.4  91/01/08  15:48:24  rpd
 * 	Added continuation argument to thread_block.
 * 	[90/12/27            rpd]
 * 
 * Revision 2.3  90/12/05  23:34:48  af
 * 	Recovered from pmax merge.. and from the destruction of a disk.
 * 	[90/12/03  23:40:40  af]
 * 
 * Revision 2.1.1.1  90/11/01  03:39:09  af
 * 	Created, from the DEC specs:
 * 	"PMAZ-AA TURBOchannel SCSI Module Functional Specification"
 * 	Workstation Systems Engineering, Palo Alto, CA. Aug 27, 1990.
 * 	And from the NCR data sheets
 * 	"NCR 53C94, 53C95, 53C96 Advances SCSI Controller"
 * 	[90/09/03            af]
 */

/*
 *	File: scsi_53C94_hdw.h
 * 	Author: Alessandro Forin, Carnegie Mellon University
 *	Date:	9/90
 *
 *	Bottom layer of the SCSI driver: chip-dependent functions
 *
 *	This file contains the code that is specific to the NCR 53C94
 *	SCSI chip (Host Bus Adapter in SCSI parlance): probing, start
 *	operation, and interrupt routine.
 */

/*
 * This layer works based on small simple 'scripts' that are installed
 * at the start of the command and drive the chip to completion.
 * The idea comes from the specs of the NCR 53C700 'script' processor.
 *
 * There are various reasons for this, mainly
 * - Performance: identify the common (successful) path, and follow it;
 *   at interrupt time no code is needed to find the current status
 * - Code size: it should be easy to compact common operations
 * - Adaptability: the code skeleton should adapt to different chips without
 *   terrible complications.
 * - Error handling: and it is easy to modify the actions performed
 *   by the scripts to cope with strange but well identified sequences
 *
 */

#include <asc.h>
#if NASC > 0

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dkstat.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/errno.h>
#include <sys/device.h>

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

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

#include <pica/dev/dma.h>
#include <pica/dev/scsi.h>
#include <pica/dev/ascreg.h>

#include <pica/pica/pica.h>
#include <pica/pica/picatype.h>


#define	readback(a)	{ register int foo; foo = (a); }
extern int cputype;

/*
 * In 4ns ticks.
 */
int	asc_to_scsi_period[] = {
	32,
	33,
	34,
	35,
	5,
	5,
	6,
	7,
	8,
	9,
	10,
	11,
	12,
	13,
	14,
	15,
	16,
	17,
	18,
	19,
	20,
	21,
	22,
	23,
	24,
	25,
	26,
	27,
	28,
	29,
	30,
	31,
};

/*
 * Internal forward declarations.
 */
static void asc_reset();
static void asc_startcmd();

#ifdef DEBUG
int	asc_debug = 1;
int	asc_debug_cmd;
int	asc_debug_bn;
int	asc_debug_sz;
#define NLOG 8
struct asc_log {
	u_int	status;
	u_char	state;
	u_char	msg;
	int	target;
	int	resid;
} asc_log[NLOG], *asc_logp = asc_log;
#define PACK(unit, status, ss, ir) \
	((unit << 24) | (status << 16) | (ss << 8) | ir)
#endif

/*
 * Scripts are entries in a state machine table.
 * A script has four parts: a pre-condition, an action, a command to the chip,
 * and an index into asc_scripts for the next state. The first triggers error
 * handling if not satisfied and in our case it is formed by the
 * values of the interrupt register and status register, this
 * basically captures the phase of the bus and the TC and BS
 * bits.  The action part is just a function pointer, and the
 * command is what the 53C94 should be told to do at the end
 * of the action processing.  This command is only issued and the
 * script proceeds if the action routine returns TRUE.
 * See asc_intr() for how and where this is all done.
 */
typedef struct script {
	int		condition;	/* expected state at interrupt time */
	int		(*action)();	/* extra operations */
	int		command;	/* command to the chip */
	struct script	*next;		/* index into asc_scripts for next state */
} script_t;

/* Matching on the condition value */
#define	SCRIPT_MATCH(ir, csr)		((ir) | (((csr) & 0x67) << 8))

/* forward decls of script actions */
static int script_nop();		/* when nothing needed */
static int asc_end();			/* all come to an end */
static int asc_get_status();		/* get status from target */
static int asc_dma_in();		/* start reading data from target */
static int asc_last_dma_in();		/* cleanup after all data is read */
static int asc_resume_in();		/* resume data in after a message */
static int asc_resume_dma_in();		/* resume DMA after a disconnect */
static int asc_dma_out();		/* send data to target via dma */
static int asc_last_dma_out();		/* cleanup after all data is written */
static int asc_resume_out();		/* resume data out after a message */
static int asc_resume_dma_out();	/* resume DMA after a disconnect */
static int asc_sendsync();		/* negotiate sync xfer */
static int asc_replysync();		/* negotiate sync xfer */
static int asc_msg_in();		/* process a message byte */
static int asc_disconnect();		/* process an expected disconnect */

/* Define the index into asc_scripts for various state transitions */
#define	SCRIPT_DATA_IN		0
#define	SCRIPT_CONTINUE_IN	2
#define	SCRIPT_DATA_OUT		3
#define	SCRIPT_CONTINUE_OUT	5
#define	SCRIPT_SIMPLE		6
#define	SCRIPT_GET_STATUS	7
#define	SCRIPT_DONE		8
#define	SCRIPT_MSG_IN		9
#define	SCRIPT_REPLY_SYNC	11
#define	SCRIPT_TRY_SYNC		12
#define	SCRIPT_DISCONNECT	15
#define	SCRIPT_RESEL		16
#define	SCRIPT_RESUME_IN	17
#define	SCRIPT_RESUME_DMA_IN	18
#define	SCRIPT_RESUME_OUT	19
#define	SCRIPT_RESUME_DMA_OUT	20
#define	SCRIPT_RESUME_NO_DATA	21

/*
 * Scripts
 */
script_t asc_scripts[] = {
	/* start data in */
	{SCRIPT_MATCH(ASC_INT_FC | ASC_INT_BS, ASC_PHASE_DATAI),	/*  0 */
		asc_dma_in, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_IN + 1]},
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_STATUS),			/*  1 */
		asc_last_dma_in, ASC_CMD_I_COMPLETE,
		&asc_scripts[SCRIPT_GET_STATUS]},

	/* continue data in after a chunk is finished */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAI),			/*  2 */
		asc_dma_in, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_IN + 1]},

	/* start data out */
	{SCRIPT_MATCH(ASC_INT_FC | ASC_INT_BS, ASC_PHASE_DATAO),	/*  3 */
		asc_dma_out, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_OUT + 1]},
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_STATUS),			/*  4 */
		asc_last_dma_out, ASC_CMD_I_COMPLETE,
		&asc_scripts[SCRIPT_GET_STATUS]},

	/* continue data out after a chunk is finished */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAO),			/*  5 */
		asc_dma_out, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_OUT + 1]},

	/* simple command with no data transfer */
	{SCRIPT_MATCH(ASC_INT_FC | ASC_INT_BS, ASC_PHASE_STATUS),	/*  6 */
		script_nop, ASC_CMD_I_COMPLETE,
		&asc_scripts[SCRIPT_GET_STATUS]},

	/* get status and finish command */
	{SCRIPT_MATCH(ASC_INT_FC, ASC_PHASE_MSG_IN),			/*  7 */
		asc_get_status, ASC_CMD_MSG_ACPT,
		&asc_scripts[SCRIPT_DONE]},
	{SCRIPT_MATCH(ASC_INT_DISC, 0),					/*  8 */
		asc_end, ASC_CMD_NOP,
		&asc_scripts[SCRIPT_DONE]},

	/* message in */
	{SCRIPT_MATCH(ASC_INT_FC, ASC_PHASE_MSG_IN),			/*  9 */
		asc_msg_in, ASC_CMD_MSG_ACPT,
		&asc_scripts[SCRIPT_MSG_IN + 1]},
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_MSG_IN),			/* 10 */
		script_nop, ASC_CMD_XFER_INFO,
		&asc_scripts[SCRIPT_MSG_IN]},

	/* send synchonous negotiation reply */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_MSG_OUT),			/* 11 */
		asc_replysync, ASC_CMD_XFER_INFO,
		&asc_scripts[SCRIPT_REPLY_SYNC]},

	/* try to negotiate synchonous transfer parameters */
	{SCRIPT_MATCH(ASC_INT_FC | ASC_INT_BS, ASC_PHASE_MSG_OUT),	/* 12 */
		asc_sendsync, ASC_CMD_XFER_INFO,
		&asc_scripts[SCRIPT_TRY_SYNC + 1]},
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_MSG_IN),			/* 13 */
		script_nop, ASC_CMD_XFER_INFO,
		&asc_scripts[SCRIPT_MSG_IN]},
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_COMMAND),			/* 14 */
		script_nop, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_RESUME_NO_DATA]},

	/* handle a disconnect */
	{SCRIPT_MATCH(ASC_INT_DISC, ASC_PHASE_DATAO),			/* 15 */
		asc_disconnect, ASC_CMD_ENABLE_SEL,
		&asc_scripts[SCRIPT_RESEL]},

	/* reselect sequence: this is just a placeholder so match fails */
	{SCRIPT_MATCH(0, ASC_PHASE_MSG_IN),				/* 16 */
		script_nop, ASC_CMD_MSG_ACPT,
		&asc_scripts[SCRIPT_RESEL]},

	/* resume data in after a message */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAI),			/* 17 */
		asc_resume_in, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_IN + 1]},

	/* resume partial DMA data in after a message */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAI),			/* 18 */
		asc_resume_dma_in, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_IN + 1]},

	/* resume data out after a message */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAO),			/* 19 */
		asc_resume_out, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_OUT + 1]},

	/* resume partial DMA data out after a message */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_DATAO),			/* 20 */
		asc_resume_dma_out, ASC_CMD_XFER_INFO | ASC_CMD_DMA,
		&asc_scripts[SCRIPT_DATA_OUT + 1]},

	/* resume after a message when there is no more data */
	{SCRIPT_MATCH(ASC_INT_BS, ASC_PHASE_STATUS),			/* 21 */
		script_nop, ASC_CMD_I_COMPLETE,
		&asc_scripts[SCRIPT_GET_STATUS]},
};

/*
 * State kept for each active SCSI device.
 */
typedef struct scsi_state {
	script_t *script;	/* saved script while processing error */
	struct scsi_generic cmd;/* storage for scsi command */
	int	statusByte;	/* status byte returned during STATUS_PHASE */
	u_int	dmaBufSize;	/* DMA buffer size */
	int	dmalen;		/* amount to transfer in this chunk */
	int	dmaresid;	/* amount not transfered if chunk suspended */
	int	cmdlen;		/* length of command in cmd */
	int	buflen;		/* total remaining amount of data to transfer */
	vm_offset_t buf;	/* current pointer within scsicmd->buf */
	int	flags;		/* see below */
	int	msglen;		/* number of message bytes to read */
	int	msgcnt;		/* number of message bytes received */
	u_char	sync_period;	/* DMA synchronous period */
	u_char	sync_offset;	/* DMA synchronous xfer offset or 0 if async */
	u_char	msg_out;	/* next MSG_OUT byte to send */
	u_char	msg_in[16];	/* buffer for multibyte messages */
} State;

/* state flags */
#define DISCONN		0x001	/* true if currently disconnected from bus */
#define DMA_IN_PROGRESS	0x002	/* true if data DMA started */
#define DMA_IN		0x004	/* true if reading from SCSI device */
#define DMA_OUT		0x010	/* true if writing to SCSI device */
#define DID_SYNC	0x020	/* true if synchronous offset was negotiated */
#define TRY_SYNC	0x040	/* true if try neg. synchronous offset */
#define PARITY_ERR	0x080	/* true if parity error seen */
#define	CHECK_SENSE	0x100	/* true if doing sense command */

/*
 * State kept for each active SCSI host interface (53C94).
 */
struct asc_softc {
	struct device	sc_dev;		/* use as a device */
	asc_regmap_t	*regs;		/* chip address */
	dma_softc_t	__dma;		/* stupid macro..... */
	dma_softc_t	*dma;		/* dma control structure */
	int		sc_id;		/* SCSI ID of this interface */
	int		myidmask;	/* ~(1 << myid) */
	int		state;		/* current SCSI connection state */
	int		target;		/* target SCSI ID if busy */
	script_t	*script;	/* next expected interrupt & action */
	struct scsi_xfer *cmdq[ASC_NCMD];/* Pointer to queued commands */
	struct scsi_xfer *cmd[ASC_NCMD];/* Pointer to current active command */
	State		st[ASC_NCMD];	/* state info for each active command */
	int		min_period;	/* Min transfer period clk/byte */
	int		max_period;	/* Max transfer period clk/byte */
	int		ccf;		/* CCF, whatever that really is? */
	int		timeout_250;	/* 250ms timeout */
	int		tb_ticks;	/* 4ns. ticks/tb channel ticks */
	struct scsi_link sc_link;	/* scsi link struct */
};

#define	ASC_STATE_IDLE		0	/* idle state */
#define	ASC_STATE_BUSY		1	/* selecting or currently connected */
#define ASC_STATE_TARGET	2	/* currently selected as target */
#define ASC_STATE_RESEL		3	/* currently waiting for reselect */

typedef struct asc_softc *asc_softc_t;

/*
 * Autoconfiguration data for config.
 */
int	ascmatch __P((struct device *, void *, void *));
void	ascattach __P((struct device *, struct device *, void *));
int	ascprint(void *, char *);

int	asc_doprobe __P((void *, int, int, struct device *));

extern struct cfdriver asccd;
struct cfdriver asccd = {
	NULL, "asc", ascmatch, ascattach, DV_DULL, sizeof(struct asc_softc), 0
};

/*
 *  Glue to the machine dependent scsi
 */
int asc_scsi_cmd __P((struct scsi_xfer *));
void asc_minphys __P((struct buf *));

struct scsi_adapter asc_switch = {
	asc_scsi_cmd,
/*XXX*/	asc_minphys,	/* no max transfer size, DMA driver negotiates */
	NULL,
	NULL,
};

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

static int	asc_probe();
static void	asc_start();
static int	asc_intr();

/*
 * Match driver based on name
 */
int
ascmatch(parent, match, aux)
	struct device *parent;
	void *match;
	void *aux;
{
	struct cfdata *cf = match;
	struct confargs *ca = aux;

	if(!BUS_MATCHNAME(ca, "asc"))
		return(0);
	return(1);
}

void
ascattach(parent, self, aux)
	struct device *parent;
	struct device *self;
	void *aux;
{
	register struct confargs *ca = aux;
	register asc_softc_t asc = (void *)self;
	register asc_regmap_t *regs;
	int id, s, i;
	int bufsiz;

	/*
	 * Initialize hw descriptor, cache some pointers
	 */
	asc->regs = (asc_regmap_t *)BUS_CVTADDR(ca);

	/*
	 * Set up machine dependencies.
	 * 1) how to do dma
	 * 2) timing based on chip clock frequency
	 */
	switch (cputype) {
	case ACER_PICA_61:
		asc->dma = &asc->__dma;
		asc_dma_init(asc->dma);
		break;
	default:
	};
	/*
	 * Now for timing. The pica has a 25Mhz
	 */
	switch (cputype) {
	case ACER_PICA_61:
		asc->min_period = ASC_MIN_PERIOD25;
		asc->max_period = ASC_MAX_PERIOD25;
		asc->ccf = ASC_CCF(25);
		asc->timeout_250 = ASC_TIMEOUT_250(25, asc->ccf);
		asc->tb_ticks = 10;
		break;
	default:
		asc->min_period = ASC_MIN_PERIOD12;
		asc->max_period = ASC_MAX_PERIOD12;
		asc->ccf = ASC_CCF(13);
		asc->timeout_250 = ASC_TIMEOUT_250(13, asc->ccf);
		asc->tb_ticks = 20;
		break;
	};

	asc->state = ASC_STATE_IDLE;
	asc->target = -1;

	regs = asc->regs;

	/*
	 * Reset chip, fully.  Note that interrupts are already enabled.
	 */
	s = splbio();

	/* preserve our ID for now */
	asc->sc_id = regs->asc_cnfg1 & ASC_CNFG1_MY_BUS_ID;
	asc->myidmask = ~(1 << asc->sc_id);

	asc_reset(asc, regs);

	/*
	 * Our SCSI id on the bus.
	 * The user can set this via the prom on 3maxen/picaen.
	 * If this changes it is easy to fix: make a default that
	 * can be changed as boot arg.
	 */
#ifdef	unneeded
	regs->asc_cnfg1 = (regs->asc_cnfg1 & ~ASC_CNFG1_MY_BUS_ID) |
			      (scsi_initiator_id[unit] & 0x7);
	asc->sc_id = regs->asc_cnfg1 & ASC_CNFG1_MY_BUS_ID;
#endif
	id = asc->sc_id;
	splx(s);

	/*
	 * Give each target its DMA buffer region.
	 * The buffer address is the same for all targets,
	 * the allocated dma viritual scatter/gather space.
	 */
	for (i = 0; i < ASC_NCMD; i++) {
		asc->st[i].dmaBufSize = bufsiz;
	}

	/*
	 * Set up interrupt handler.
         */
	BUS_INTR_ESTABLISH(ca, asc_intr, (void *)asc);

	printf(": NCR53C94, target %d\n", id);

	/*
	 * Fill in the prototype scsi link.
	 */
	asc->sc_link.adapter_softc = asc;
	asc->sc_link.adapter_target = asc->sc_id;
	asc->sc_link.adapter = &asc_switch;
	asc->sc_link.device = &asc_dev;
	asc->sc_link.openings = 2;

	/*
	 * Now try to attach all the sub devices.
	 */
	config_found(self, &asc->sc_link, ascprint);
}

int
ascprint(aux, name)
	void *aux;
	char *name;
{
	return -1;
}

/*
 *  Driver breaks down request transfer size.
 */
void
asc_minphys(bp)
	struct buf *bp;
{
}

/*
 * Start activity on a SCSI device.
 * We maintain information on each device separately since devices can
 * connect/disconnect during an operation.
 */
int
asc_scsi_cmd(xs)
	struct scsi_xfer *xs;
{
	struct scsi_link *sc_link = xs->sc_link;
	struct asc_softc *asc = sc_link->adapter_softc;
	State *state = &asc->st[sc_link->target];

	int flags, s;

	flags = xs->flags;

	/*
	 *  Flush caches for any data buffer
	 */
	if(xs->datalen != 0) {
		MachHitFlushDCache(xs->data, xs->datalen);
	}
	/*
	 *  The hack on the next few lines are to avoid buffers
	 *  mapped to UADDR. Realloc to the kva uarea address.
	 */
	if((u_int)(xs->data) >= UADDR) {
		xs->data = ((u_int)(xs->data) & ~UADDR) + (u_char *)(curproc->p_addr);
	}

	/*
	 * Check if another command is already in progress.
	 * We may have to change this if we allow SCSI devices with
	 * separate LUNs.
	 */
	s = splbio();
	if (asc->cmd[sc_link->target]) {
		if (asc->cmdq[sc_link->target]) {
			splx(s);
			printf("asc_scsi_cmd: called when target busy");
			xs->error = XS_DRIVER_STUFFUP;
			return TRY_AGAIN_LATER;
		}
		asc->cmdq[sc_link->target] = xs;
		splx(s);
		return SUCCESSFULLY_QUEUED;
	}
	asc->cmd[sc_link->target] = xs;

	/*
	 *  Going to launch.
	 *  Make a local copy of the command and some pointers.
	 */
	asc_startcmd(asc, sc_link->target);

	/*
	 *  If in startup, interrupts not usable yet.
	 */
	if(flags & SCSI_POLL) {
		return(asc_poll(asc,sc_link->target));
	}
	splx(s);
	return SUCCESSFULLY_QUEUED;
}

int
asc_poll(asc, target)
	struct asc_softc *asc;
	int target;
{
	struct scsi_xfer *scsicmd = asc->cmd[target];
	int count = scsicmd->timeout * 10;

	while(count) {
		if(asc->regs->asc_status &ASC_CSR_INT) {
			asc_intr(asc);
		}
		if(scsicmd->flags & ITSDONE)
			break;
		DELAY(5);
		count--;
	}
	if(count == 0) {
		scsicmd->error = XS_TIMEOUT;
		asc_end(asc, 0, 0, 0);
	}
	return COMPLETE;
}

static void
asc_reset(asc, regs)
	asc_softc_t asc;
	asc_regmap_t *regs;
{

	/*
	 * Reset chip and wait till done
	 */
	regs->asc_cmd = ASC_CMD_RESET;
	MachEmptyWriteBuffer(); DELAY(25);

	/* spec says this is needed after reset */
	regs->asc_cmd = ASC_CMD_NOP;
	MachEmptyWriteBuffer(); DELAY(25);

	/*
	 * Set up various chip parameters
	 */
	regs->asc_ccf = asc->ccf;
	MachEmptyWriteBuffer(); DELAY(25);
	regs->asc_sel_timo = asc->timeout_250;
	/* restore our ID */
	regs->asc_cnfg1 = asc->sc_id | ASC_CNFG1_P_CHECK;
	/* include ASC_CNFG2_SCSI2 if you want to allow SCSI II commands */
	regs->asc_cnfg2 = /* ASC_CNFG2_RFB | ASC_CNFG2_SCSI2 | */ ASC_CNFG2_EPL;
	regs->asc_cnfg3 = 0;
	/* zero anything else */
	ASC_TC_PUT(regs, 0);
	regs->asc_syn_p = asc->min_period;
	regs->asc_syn_o = 0;	/* async for now */
	MachEmptyWriteBuffer();
}

/*
 * Start a SCSI command on a target.
 */
static void
asc_startcmd(asc, target)
	asc_softc_t asc;
	int target;
{
	asc_regmap_t *regs;
	State *state;
	struct scsi_xfer *scsicmd;
	int len;

	/*
	 * See if another target is currently selected on this SCSI bus.
	 */
	if (asc->target >= 0)
		return;

	regs = asc->regs;

	/*
	 * If a reselection is in progress, it is Ok to ignore it since
	 * the ASC will automatically cancel the command and flush
	 * the FIFO if the ASC is reselected before the command starts.
	 * If we try to use ASC_CMD_DISABLE_SEL, we can hang the system if
	 * a reselect occurs before starting the command.
	 */

	asc->state = ASC_STATE_BUSY;
	asc->target = target;

	/* cache some pointers */
	scsicmd = asc->cmd[target];
	state = &asc->st[target];

	/*
	 * Init the chip and target state.
	 */
	state->flags = state->flags & (DID_SYNC | CHECK_SENSE);
	state->script = (script_t *)0;
	state->msg_out = SCSI_NO_OP;

	/*
	 * Set up for DMA of command output. Also need to flush cache.
	 */
	if(!(state->flags & CHECK_SENSE)) {
		bcopy(scsicmd->cmd, &state->cmd, scsicmd->cmdlen);
		state->cmdlen = scsicmd->cmdlen;
		state->buf = (vm_offset_t)scsicmd->data;
		state->buflen = scsicmd->datalen;
	}
	len = state->cmdlen;
	state->dmalen = len;
	MachHitFlushDCache(&state->cmd, len);
	
#ifdef DEBUG
	if (asc_debug > 1) {
		printf("asc_startcmd: %s target %d cmd %x len %d\n",
			asc->sc_dev.dv_xname, target,
			state->cmd.opcode, state->buflen);
	}
#endif

	/* check for simple SCSI command with no data transfer */
	if(state->flags & CHECK_SENSE) {
		asc->script = &asc_scripts[SCRIPT_DATA_IN];
		state->flags |= DMA_IN;
	}
	else if (scsicmd->flags & SCSI_DATA_OUT) {
		asc->script = &asc_scripts[SCRIPT_DATA_OUT];
		state->flags |= DMA_OUT;
	}
	else if (scsicmd->flags & SCSI_DATA_IN) {
		asc->script = &asc_scripts[SCRIPT_DATA_IN];
		state->flags |= DMA_IN;
	}
	else if (state->buflen == 0) {
		/* check for sync negotiation */
		if ((scsicmd->flags & /* SCSICMD_USE_SYNC */ 0) &&
		    !(state->flags & DID_SYNC)) {
			asc->script = &asc_scripts[SCRIPT_TRY_SYNC];
			state->flags |= TRY_SYNC;
		} else
			asc->script = &asc_scripts[SCRIPT_SIMPLE];
		state->buf = (vm_offset_t)0;
	}

#ifdef DEBUG
	asc_debug_cmd = state->cmd.opcode;
	if (state->cmd.opcode == SCSI_READ_EXT) {
		asc_debug_bn = (state->cmd.bytes[1] << 24) |
			(state->cmd.bytes[2] << 16) |
			(state->cmd.bytes[3] << 8) |
			 state->cmd.bytes[4];
		asc_debug_sz = (state->cmd.bytes[6] << 8) | state->cmd.bytes[7];
	}
	asc_logp->status = PACK(asc->sc_dev.dv_unit, 0, 0, asc_debug_cmd);
	asc_logp->target = asc->target;
	asc_logp->state = asc->script - asc_scripts;
	asc_logp->msg = SCSI_DIS_REC_IDENTIFY;
	asc_logp->resid = scsicmd->datalen;
	if (++asc_logp >= &asc_log[NLOG])
		asc_logp = asc_log;
#endif

	/* preload the FIFO with the message to be sent */
	regs->asc_fifo = SCSI_DIS_REC_IDENTIFY | (scsicmd->sc_link->lun & 0x07);
	MachEmptyWriteBuffer();

	/* initialize the DMA */
	DMA_START(asc->dma, (caddr_t)&state->cmd, len, DMA_TO_DEV);
	ASC_TC_PUT(regs, len);
	readback(regs->asc_cmd);

	regs->asc_dbus_id = target;
	readback(regs->asc_dbus_id);
	regs->asc_syn_p = state->sync_period;
	readback(regs->asc_syn_p);
	regs->asc_syn_o = state->sync_offset;
	readback(regs->asc_syn_o);

	if (state->flags & TRY_SYNC)
		regs->asc_cmd = ASC_CMD_SEL_ATN_STOP;
	else
		regs->asc_cmd = ASC_CMD_SEL_ATN | ASC_CMD_DMA;
	readback(regs->asc_cmd);
}

/*
 * Interrupt routine
 *	Take interrupts from the chip
 *
 * Implementation:
 *	Move along the current command's script if
 *	all is well, invoke error handler if not.
 */
int
asc_intr(sc)
	void *sc;
{
	asc_softc_t asc = sc;
	asc_regmap_t *regs = asc->regs;
	State *state;
	script_t *scpt;
	int ss, ir, status;

	/* collect ephemeral information */
	status = regs->asc_status;
again:
	ss = regs->asc_ss;
	ir = regs->asc_intr;	/* this resets the previous two */
	scpt = asc->script;

#ifdef DEBUG
	asc_logp->status = PACK(asc->sc_dev.dv_unit, status, ss, ir);
	asc_logp->target = (asc->state == ASC_STATE_BUSY) ? asc->target : -1;
	asc_logp->state = scpt - asc_scripts;
	asc_logp->msg = -1;
	asc_logp->resid = 0;
	if (++asc_logp >= &asc_log[NLOG])
		asc_logp = asc_log;
	if (asc_debug > 2)
		printf("asc_intr: status %x ss %x ir %x cond %d:%x\n",
			status, ss, ir, scpt - asc_scripts, scpt->condition);
#endif

	/* check the expected state */
	if (SCRIPT_MATCH(ir, status) == scpt->condition) {
		/*
		 * Perform the appropriate operation, then proceed.
		 */
		if ((*scpt->action)(asc, status, ss, ir)) {
			regs->asc_cmd = scpt->command;
			readback(regs->asc_cmd);
			asc->script = scpt->next;
		}
		goto done;
	}

	/*
	 * Check for parity error.
	 * Hardware will automatically set ATN
	 * to request the device for a MSG_OUT phase.
	 */
	if (status & ASC_CSR_PE) {
		printf("%s: SCSI device %d: incomming parity error seen\n",
			asc->sc_dev.dv_xname, asc->target);
		asc->st[asc->target].flags |= PARITY_ERR;
	}

	/*
	 * Check for gross error.
	 * Probably a bug in a device driver.
	 */
	if (status & ASC_CSR_GE) {
		printf("%s: SCSI device %d: gross error\n",
			asc->sc_dev.dv_xname, asc->target);
		goto abort;
	}

	/* check for message in or out */
	if ((ir & ~ASC_INT_FC) == ASC_INT_BS) {
		register int len, fifo;

		state = &asc->st[asc->target];
		switch (ASC_PHASE(status)) {
		case ASC_PHASE_DATAI:
		case ASC_PHASE_DATAO:
			ASC_TC_GET(regs, len);
			fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
			printf("asc_intr: data overrun: buflen %d dmalen %d tc %d fifo %d\n",
				state->buflen, state->dmalen, len, fifo);
			goto abort;

		case ASC_PHASE_MSG_IN:
			break;

		case ASC_PHASE_MSG_OUT:
			/*
			 * Check for parity error.
			 * Hardware will automatically set ATN
			 * to request the device for a MSG_OUT phase.
			 */
			if (state->flags & PARITY_ERR) {
				state->flags &= ~PARITY_ERR;
				state->msg_out = SCSI_MESSAGE_PARITY_ERROR;
				/* reset message in counter */
				state->msglen = 0;
			} else
				state->msg_out = SCSI_NO_OP;
			regs->asc_fifo = state->msg_out;
			regs->asc_cmd = ASC_CMD_XFER_INFO;
			readback(regs->asc_cmd);
			goto done;

		case ASC_PHASE_STATUS:
			/* probably an error in the SCSI command */
			asc->script = &asc_scripts[SCRIPT_GET_STATUS];
			regs->asc_cmd = ASC_CMD_I_COMPLETE;
			readback(regs->asc_cmd);
			goto done;

		default:
			goto abort;
		}

		if (state->script)
			goto abort;

		/* check for DMA in progress */
		ASC_TC_GET(regs, len);
		fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
		/* flush any data in the FIFO */
		if (fifo) {
			if (state->flags & DMA_OUT)
				len += fifo;
			else if (state->flags & DMA_IN) {
				u_char *cp;

				printf("asc_intr: IN: dmalen %d len %d fifo %d\n",
					state->dmalen, len, fifo); /* XXX */
				len += fifo;
				cp = (u_char *)state->buf + (state->dmalen - len);
				while (fifo-- > 0)
					*cp++ = regs->asc_fifo;
/*XXX Check, need to flush cache ?*/
			} else
				printf("asc_intr: dmalen %d len %d fifo %d\n",
					state->dmalen, len, fifo); /* XXX */
			regs->asc_cmd = ASC_CMD_FLUSH;
			readback(regs->asc_cmd);
			DELAY(2);
		}
		if (len && (state->flags & DMA_IN_PROGRESS)) {
			/* save number of bytes still to be sent or received */
			state->dmaresid = len;
			state->flags &= ~DMA_IN_PROGRESS;
			ASC_TC_PUT(regs, 0);
#ifdef DEBUG
			if (asc_logp == asc_log)
				asc_log[NLOG - 1].resid = len;
			else
				asc_logp[-1].resid = len;
#endif
			/* setup state to resume to */
			if (state->flags & DMA_IN) {
				/*
				 * Since the ASC_CNFG3_SRB bit of the
				 * cnfg3 register bit is not set,
				 * we just transferred an extra byte.
				 * Since we can't resume on an odd byte
				 * boundary, we copy the valid data out
				 * and resume DMA at the start address.
				 */
				if (len & 1) {
					printf("asc_intr: msg in len %d (fifo %d)\n",
						len, fifo); /* XXX */
					len = state->dmalen - len;
					goto do_in;
				}
				state->script =
					&asc_scripts[SCRIPT_RESUME_DMA_IN];
			} else if (state->flags & DMA_OUT)
				state->script =
					&asc_scripts[SCRIPT_RESUME_DMA_OUT];
			else
				state->script = asc->script;
		} else if (state->flags & DMA_IN) {
			if (len) {
#ifdef DEBUG
				printf("asc_intr: 1: bn %d len %d (fifo %d)\n",
					asc_debug_bn, len, fifo); /* XXX */
#endif
				goto abort;
			}
			/* setup state to resume to */
			if (state->flags & DMA_IN_PROGRESS) {
				len = state->dmalen;
				state->flags &= ~DMA_IN_PROGRESS;
			do_in:
				DMA_END(asc->dma);
				state->buf += len;
				state->buflen -= len;
			}
			if (state->buflen)
				state->script =
				    &asc_scripts[SCRIPT_RESUME_IN];
			else
				state->script =
				    &asc_scripts[SCRIPT_RESUME_NO_DATA];
		} else if (state->flags & DMA_OUT) {
			if (len) {
				printf("asc_intr: 2: len %d (fifo %d)\n", len,
					fifo); /* XXX */
				goto abort;
			}
			/*
			 * If this is the last chunk, the next expected
			 * state is to get status.
			 */
			if (state->flags & DMA_IN_PROGRESS) {
				state->flags &= ~DMA_IN_PROGRESS;
				DMA_END(asc->dma);
				len = state->dmalen;
				state->buf += len;
				state->buflen -= len;
			}
			if (state->buflen)
				state->script =
				    &asc_scripts[SCRIPT_RESUME_OUT];
			else
				state->script =
				    &asc_scripts[SCRIPT_RESUME_NO_DATA];
		} else if (asc->script == &asc_scripts[SCRIPT_SIMPLE])
			state->script = &asc_scripts[SCRIPT_RESUME_NO_DATA];
		else
			state->script = asc->script;

		/* setup to receive a message */
		asc->script = &asc_scripts[SCRIPT_MSG_IN];
		state->msglen = 0;
		regs->asc_cmd = ASC_CMD_XFER_INFO;
		readback(regs->asc_cmd);
		goto done;
	}

	/* check for SCSI bus reset */
	if (ir & ASC_INT_RESET) {
		register int i;

		printf("%s: SCSI bus reset!!\n", asc->sc_dev.dv_xname);
		/* need to flush any pending commands */
		for (i = 0; i < ASC_NCMD; i++) {
			if (!asc->cmd[i])
				continue;
			asc->cmd[i]->error = XS_DRIVER_STUFFUP;
			asc_end(asc, 0, 0, 0);
		}
		/* rearbitrate synchronous offset */
		for (i = 0; i < ASC_NCMD; i++) {
			asc->st[i].sync_offset = 0;
			asc->st[i].flags = 0;
		}
		asc->target = -1;
		return;
	}

	/* check for command errors */
	if (ir & ASC_INT_ILL)
		goto abort;

	/* check for disconnect */
	if (ir & ASC_INT_DISC) {
		state = &asc->st[asc->target];
		switch (asc->script - asc_scripts) {
		case SCRIPT_DONE:
		case SCRIPT_DISCONNECT:
			/*
			 * Disconnects can happen normally when the
			 * command is complete with the phase being
			 * either ASC_PHASE_DATAO or ASC_PHASE_MSG_IN.
			 * The SCRIPT_MATCH() only checks for one phase
			 * so we can wind up here.
			 * Perform the appropriate operation, then proceed.
			 */
			if ((*scpt->action)(asc, status, ss, ir)) {
				regs->asc_cmd = scpt->command;
				readback(regs->asc_cmd);
				asc->script = scpt->next;
			}
			goto done;

		case SCRIPT_TRY_SYNC:
		case SCRIPT_SIMPLE:
		case SCRIPT_DATA_IN:
		case SCRIPT_DATA_OUT: /* one of the starting scripts */
			if (ASC_SS(ss) == 0) {
				/* device did not respond */
				if (regs->asc_flags & ASC_FLAGS_FIFO_CNT) {
					regs->asc_cmd = ASC_CMD_FLUSH;
					readback(regs->asc_cmd);
				}
				asc->cmd[asc->target]->error = XS_DRIVER_STUFFUP;
				asc_end(asc, status, ss, ir);
				return;
			}
			/* FALLTHROUGH */

		default:
			printf("%s: SCSI device %d: unexpected disconnect\n",
				asc->sc_dev.dv_xname, asc->target);
#ifdef DEBUG
			asc_DumpLog("asc_disc");
#endif
			/*
			 * On rare occasions my RZ24 does a disconnect during
			 * data in phase and the following seems to keep it
			 * happy.
			 * XXX Should a scsi disk ever do this??
			 */
			asc->script = &asc_scripts[SCRIPT_RESEL];
			asc->state = ASC_STATE_RESEL;
			state->flags |= DISCONN;
			regs->asc_cmd = ASC_CMD_ENABLE_SEL;
			readback(regs->asc_cmd);
			return;
		}
	}

	/* check for reselect */
	if (ir & ASC_INT_RESEL) {
		unsigned fifo, id, msg;

		fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
		if (fifo < 2)
			goto abort;
		/* read unencoded SCSI ID and convert to binary */
		msg = regs->asc_fifo & asc->myidmask;
		for (id = 0; (msg & 1) == 0; id++)
			msg >>= 1;
		/* read identify message */
		msg = regs->asc_fifo;
#ifdef DEBUG
		if (asc_logp == asc_log)
			asc_log[NLOG - 1].msg = msg;
		else
			asc_logp[-1].msg = msg;
#endif
		asc->state = ASC_STATE_BUSY;
		asc->target = id;
		state = &asc->st[id];
		asc->script = state->script;
		state->script = (script_t *)0;
		if (!(state->flags & DISCONN))
			goto abort;
		state->flags &= ~DISCONN;
		regs->asc_syn_p = state->sync_period;
		regs->asc_syn_o = state->sync_offset;
		regs->asc_cmd = ASC_CMD_MSG_ACPT;
		readback(regs->asc_cmd);
		goto done;
	}

	/* check if we are being selected as a target */
	if (ir & (ASC_INT_SEL | ASC_INT_SEL_ATN))
		goto abort;

	/*
	 * 'ir' must be just ASC_INT_FC.
	 * This is normal if canceling an ASC_ENABLE_SEL.
	 */

done:
	MachEmptyWriteBuffer();
	/*
	 * watch out for HW race conditions and setup & hold time violations
	 */
	ir = regs->asc_status;
	while (ir != (status = regs->asc_status))
		ir = status;
	if (status & ASC_CSR_INT)
		goto again;
	/*
	 * If we missed here, we will have another try later before
	 * returning to the interrupted code because the bus interrupt
	 * handler does not give up before the int queue is empty.
	 */
	return;

abort:
#ifdef DEBUG
	asc_DumpLog("asc_intr");
#endif
#if 0
	panic("asc_intr");
#else
	boot(4); /* XXX */
#endif
}

/*
 * All the many little things that the interrupt
 * routine might switch to.
 */

/* ARGSUSED */
static int
script_nop(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	return (1);
}

/* ARGSUSED */
static int
asc_get_status(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register int data;

	/*
	 * Get the last two bytes in the FIFO.
	 */
	if ((data = regs->asc_flags & ASC_FLAGS_FIFO_CNT) != 2) {
		printf("asc_get_status: cmdreg %x, fifo cnt %d\n",
		       regs->asc_cmd, data); /* XXX */
#ifdef DEBUG
		asc_DumpLog("get_status"); /* XXX */
#endif
		if (data < 2) {
			asc->regs->asc_cmd = ASC_CMD_MSG_ACPT;
			readback(asc->regs->asc_cmd);
			return (0);
		}
		do {
			data = regs->asc_fifo;
		} while ((regs->asc_flags & ASC_FLAGS_FIFO_CNT) > 2);
	}

	/* save the status byte */
	asc->st[asc->target].statusByte = data = regs->asc_fifo;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].msg = data;
	else
		asc_logp[-1].msg = data;
#endif

	/* get the (presumed) command_complete message */
	if ((data = regs->asc_fifo) == SCSI_COMMAND_COMPLETE)
		return (1);

#ifdef DEBUG
	printf("asc_get_status: status %x cmd %x\n",
		asc->st[asc->target].statusByte, data);
	asc_DumpLog("asc_get_status");
#endif
	return (0);
}

/* ARGSUSED */
static int
asc_end(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	struct scsi_xfer *scsicmd;
	struct scsi_link *sc_link;
	State *state;
	int i, target;

	asc->state = ASC_STATE_IDLE;
	target = asc->target;
	asc->target = -1;
	scsicmd = asc->cmd[target];
	sc_link = scsicmd->sc_link;
	asc->cmd[target] = (struct scsi_xfer *)0;
	state = &asc->st[target];

#ifdef DEBUG
	if (asc_debug > 1) {
		printf("asc_end: %s target %d cmd %x err %d resid %d\n",
			asc->sc_dev.dv_xname, target,
			state->cmd.opcode, scsicmd->error, state->buflen);
	}
#endif
#ifdef DIAGNOSTIC
	if (target < 0 || !scsicmd)
		panic("asc_end");
#endif

	/* look for disconnected devices */
	for (i = 0; i < ASC_NCMD; i++) {
		if (!asc->cmd[i] || !(asc->st[i].flags & DISCONN))
			continue;
		asc->regs->asc_cmd = ASC_CMD_ENABLE_SEL;
		readback(asc->regs->asc_cmd);
		asc->state = ASC_STATE_RESEL;
		asc->script = &asc_scripts[SCRIPT_RESEL];
		break;
	}

	if(scsicmd->error == XS_NOERROR && !(state->flags & CHECK_SENSE)) {
		if((state->statusByte & ST_MASK) == SCSI_CHECK) {
			struct scsi_sense *ss = (void *)&state->cmd;
			/* Save return values */
			scsicmd->resid = state->buflen;
			scsicmd->status = state->statusByte;
			/* Set up sense request command */
			bzero(ss, sizeof(*ss));
			ss->opcode = REQUEST_SENSE;
			ss->byte2 = sc_link->lun << 5;
			ss->length = sizeof(struct scsi_sense_data);
			state->cmdlen = sizeof(*ss);
			state->buf = (vm_offset_t)&scsicmd->sense;
			state->buflen = sizeof(struct scsi_sense_data);
			state->flags |= CHECK_SENSE;
			MachHitFlushDCache(state->buf, state->buflen);
			asc->cmd[target] = scsicmd;
			asc_startcmd(asc, target);
			return(0);
		}
	}

	if(scsicmd->error == XS_NOERROR && (state->flags & CHECK_SENSE)) {
		scsicmd->error = XS_SENSE;
	}
	else {
		scsicmd->resid = state->buflen;
	}
	state->flags &= ~CHECK_SENSE;

	/*
	 * Look for another device that is ready.
	 * May want to keep last one started and increment for fairness
	 * rather than always starting at zero.
	 */
	for (i = 0; i < ASC_NCMD; i++) {
		if (asc->cmd[i] == 0 && asc->cmdq[i] != 0) {
			asc->cmd[i] = asc->cmdq[i];
			asc->cmdq[i] = 0;
		}
	}
	for (i = 0; i < ASC_NCMD; i++) {
		/* don't restart a disconnected command */
		if (!asc->cmd[i] || (asc->st[i].flags & DISCONN))
			continue;
		asc_startcmd(asc, i);
		break;
	}

	/* signal device driver that the command is done */
	scsicmd->flags |= ITSDONE;
	scsi_done(scsicmd);

	return (0);
}

/* ARGSUSED */
static int
asc_dma_in(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len;

	/* check for previous chunk in buffer */
	if (state->flags & DMA_IN_PROGRESS) {
		/*
		 * Only count bytes that have been copied to memory.
		 * There may be some bytes in the FIFO if synchonous transfers
		 * are in progress.
		 */
		DMA_END(asc->dma);
		ASC_TC_GET(regs, len);
		len = state->dmalen - len;
		state->buf += len;
		state->buflen -= len;
	}

	/* setup to start reading the next chunk */
	len = state->buflen;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	if (len > state->dmaBufSize)
		len = state->dmaBufSize;
	state->dmalen = len;
	DMA_START(asc->dma, (caddr_t)state->buf, len, DMA_FROM_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_dma_in: buflen %d, len %d\n", state->buflen, len);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (len != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_IN];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_last_dma_in(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len, fifo;

	DMA_END(asc->dma);
	ASC_TC_GET(regs, len);
	fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_last_dma_in: buflen %d dmalen %d tc %d fifo %d\n",
			state->buflen, state->dmalen, len, fifo);
#endif
	if (fifo) {
		/* device must be trying to send more than we expect */
		regs->asc_cmd = ASC_CMD_FLUSH;
		readback(regs->asc_cmd);
	}
	state->flags &= ~DMA_IN_PROGRESS;
	len = state->dmalen - len;
	state->buflen -= len;

	return (1);
}

/* ARGSUSED */
static int
asc_resume_in(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len;

	/* setup to start reading the next chunk */
	len = state->buflen;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	if (len > state->dmaBufSize)
		len = state->dmaBufSize;
	state->dmalen = len;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	DMA_START(asc->dma, (caddr_t)state->buf, len, DMA_FROM_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_resume_in: buflen %d, len %d\n", state->buflen,
			len);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (len != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_IN];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_resume_dma_in(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len, off;

	/* setup to finish reading the current chunk */
	len = state->dmaresid;
	off = state->dmalen - len;
	if ((off & 1) && state->sync_offset) {
		printf("asc_resume_dma_in: odd xfer dmalen %d len %d off %d\n",
			state->dmalen, len, off); /* XXX */
		regs->asc_res_fifo = ((u_char *)state->buf)[off];
/*XXX Need to flush cache ? */
	}
	DMA_START(asc->dma, (caddr_t)state->buf + off, len, DMA_FROM_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_resume_dma_in: buflen %d dmalen %d len %d off %d\n",
			state->dmalen, state->buflen, len, off);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (state->dmalen != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_IN];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_dma_out(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len, fifo;

	if (state->flags & DMA_IN_PROGRESS) {
		/* check to be sure previous chunk was finished */
		ASC_TC_GET(regs, len);
		fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
		if (len || fifo)
			printf("asc_dma_out: buflen %d dmalen %d tc %d fifo %d\n",
				state->buflen, state->dmalen, len, fifo); /* XXX */
		len += fifo;
		len = state->dmalen - len;
		state->buf += len;
		state->buflen -= len;
	}

	/* setup for this chunk */
	len = state->buflen;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	if (len > state->dmaBufSize)
		len = state->dmaBufSize;
	state->dmalen = len;
	DMA_START(asc->dma, (caddr_t)state->buf, len, DMA_TO_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_dma_out: buflen %d, len %d\n", state->buflen, len);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (len != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_OUT];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_last_dma_out(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len, fifo;

	ASC_TC_GET(regs, len);
	fifo = regs->asc_flags & ASC_FLAGS_FIFO_CNT;
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_last_dma_out: buflen %d dmalen %d tc %d fifo %d\n",
			state->buflen, state->dmalen, len, fifo);
#endif
	if (fifo) {
		len += fifo;
		regs->asc_cmd = ASC_CMD_FLUSH;
		readback(regs->asc_cmd);
		printf("asc_last_dma_out: buflen %d dmalen %d tc %d fifo %d\n",
			state->buflen, state->dmalen, len, fifo);
	}
	state->flags &= ~DMA_IN_PROGRESS;
	len = state->dmalen - len;
	state->buflen -= len;
	return (1);
}

/* ARGSUSED */
static int
asc_resume_out(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len;

	/* setup for this chunk */
	len = state->buflen;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	if (len > state->dmaBufSize)
		len = state->dmaBufSize;
	state->dmalen = len;
#ifdef DEBUG
 	if (asc_logp == asc_log)
		asc_log[NLOG - 1].resid = len;
	else
		asc_logp[-1].resid = len;
#endif
	DMA_START(asc->dma, (caddr_t)state->buf, len, DMA_TO_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_resume_out: buflen %d, len %d\n", state->buflen,
			len);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (len != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_OUT];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_resume_dma_out(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int len, off;

	/* setup to finish writing this chunk */
	len = state->dmaresid;
	off = state->dmalen - len;
	if (off & 1) {
		printf("asc_resume_dma_out: odd xfer dmalen %d len %d off %d\n",
			state->dmalen, len, off); /* XXX */
		regs->asc_fifo = ((u_char *)state->buf)[off];
/*XXX Need to flush Cache ? */
		off++;
		len--;
	}
	DMA_START(asc->dma, (caddr_t)state->buf + off, len, DMA_TO_DEV);
	ASC_TC_PUT(regs, len);
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_resume_dma_out: buflen %d dmalen %d len %d off %d\n",
			state->dmalen, state->buflen, len, off);
#endif

	/* check for next chunk */
	state->flags |= DMA_IN_PROGRESS;
	if (state->dmalen != state->buflen) {
		regs->asc_cmd = ASC_CMD_XFER_INFO | ASC_CMD_DMA;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_CONTINUE_OUT];
		return (0);
	}
	return (1);
}

/* ARGSUSED */
static int
asc_sendsync(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];

	/* send the extended synchronous negotiation message */
	regs->asc_fifo = SCSI_EXTENDED_MSG;
	MachEmptyWriteBuffer();
	regs->asc_fifo = 3;
	MachEmptyWriteBuffer();
	regs->asc_fifo = SCSI_SYNCHRONOUS_XFER;
	MachEmptyWriteBuffer();
	regs->asc_fifo = SCSI_MIN_PERIOD;
	MachEmptyWriteBuffer();
	regs->asc_fifo = ASC_MAX_OFFSET;
	/* state to resume after we see the sync reply message */
	state->script = asc->script + 2;
	state->msglen = 0;
	return (1);
}

/* ARGSUSED */
static int
asc_replysync(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];

#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_replysync: %x %x\n",
			asc_to_scsi_period[state->sync_period] * asc->tb_ticks,
			state->sync_offset);
#endif
	/* send synchronous transfer in response to a request */
	regs->asc_fifo = SCSI_EXTENDED_MSG;
	MachEmptyWriteBuffer();
	regs->asc_fifo = 3;
	MachEmptyWriteBuffer();
	regs->asc_fifo = SCSI_SYNCHRONOUS_XFER;
	MachEmptyWriteBuffer();
	regs->asc_fifo = asc_to_scsi_period[state->sync_period] * asc->tb_ticks;
	MachEmptyWriteBuffer();
	regs->asc_fifo = state->sync_offset;
	regs->asc_cmd = ASC_CMD_XFER_INFO;
	readback(regs->asc_cmd);

	/* return to the appropriate script */
	if (!state->script) {
#ifdef DEBUG
		asc_DumpLog("asc_replsync");
#endif
		panic("asc_replysync");
	}
	asc->script = state->script;
	state->script = (script_t *)0;
	return (0);
}

/* ARGSUSED */
static int
asc_msg_in(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register asc_regmap_t *regs = asc->regs;
	register State *state = &asc->st[asc->target];
	register int msg;
	int i;

	/* read one message byte */
	msg = regs->asc_fifo;
#ifdef DEBUG
	if (asc_logp == asc_log)
		asc_log[NLOG - 1].msg = msg;
	else
		asc_logp[-1].msg = msg;
#endif

	/* check for multi-byte message */
	if (state->msglen != 0) {
		/* first byte is the message length */
		if (state->msglen < 0) {
			state->msglen = msg;
			return (1);
		}
		if (state->msgcnt >= state->msglen)
			goto abort;
		state->msg_in[state->msgcnt++] = msg;

		/* did we just read the last byte of the message? */
		if (state->msgcnt != state->msglen)
			return (1);

		/* process an extended message */
#ifdef DEBUG
		if (asc_debug > 2)
			printf("asc_msg_in: msg %x %x %x\n",
				state->msg_in[0],
				state->msg_in[1],
				state->msg_in[2]);
#endif
		switch (state->msg_in[0]) {
		case SCSI_SYNCHRONOUS_XFER:
			state->flags |= DID_SYNC;
			state->sync_offset = state->msg_in[2];

			/* convert SCSI period to ASC period */
			i = state->msg_in[1] / asc->tb_ticks;
			if (i < asc->min_period)
				i = asc->min_period;
			else if (i >= asc->max_period) {
				/* can't do sync transfer, period too long */
				printf("%s: SCSI device %d: sync xfer period too long (%d)\n",
					asc->sc_dev.dv_xname, asc->target, i);
				i = asc->max_period;
				state->sync_offset = 0;
			}
			if ((i * asc->tb_ticks) != state->msg_in[1])
				i++;
			state->sync_period = i & 0x1F;

			/*
			 * If this is a request, check minimums and
			 * send back an acknowledge.
			 */
			if (!(state->flags & TRY_SYNC)) {
				regs->asc_cmd = ASC_CMD_SET_ATN;
				readback(regs->asc_cmd);

				if (state->sync_period < asc->min_period)
					state->sync_period =
						asc->min_period;
				if (state->sync_offset > ASC_MAX_OFFSET)
					state->sync_offset =
						ASC_MAX_OFFSET;
				asc->script = &asc_scripts[SCRIPT_REPLY_SYNC];
				regs->asc_syn_p = state->sync_period;
				readback(regs->asc_syn_p);
				regs->asc_syn_o = state->sync_offset;
				readback(regs->asc_syn_o);
				regs->asc_cmd = ASC_CMD_MSG_ACPT;
				readback(regs->asc_cmd);
				return (0);
			}

			regs->asc_syn_p = state->sync_period;
			readback(regs->asc_syn_p);
			regs->asc_syn_o = state->sync_offset;
			readback(regs->asc_syn_o);
			goto done;

		default:
			printf("%s: SCSI device %d: rejecting extended message 0x%x\n",
				 asc->sc_dev.dv_xname, asc->target,
				state->msg_in[0]);
			goto reject;
		}
	}

	/* process first byte of a message */
#ifdef DEBUG
	if (asc_debug > 2)
		printf("asc_msg_in: msg %x\n", msg);
#endif
	switch (msg) {
#if 0
	case SCSI_MESSAGE_REJECT:
		printf(" did not like SYNCH xfer "); /* XXX */
		state->flags |= DID_SYNC;
		regs->asc_cmd = ASC_CMD_MSG_ACPT;
		readback(regs->asc_cmd);
		status = asc_wait(regs, ASC_CSR_INT);
		ir = regs->asc_intr;
		/* some just break out here, some dont */
		if (ASC_PHASE(status) == ASC_PHASE_MSG_OUT) {
			regs->asc_fifo = SCSI_ABORT;
			regs->asc_cmd = ASC_CMD_XFER_INFO;
			readback(regs->asc_cmd);
			status = asc_wait(regs, ASC_CSR_INT);
			ir = regs->asc_intr;
		}
		if (ir & ASC_INT_DISC) {
			asc_end(asc, status, 0, ir);
			return (0);
		}
		goto status;
#endif /* 0 */

	case SCSI_EXTENDED_MSG: /* read an extended message */
		/* setup to read message length next */
		state->msglen = -1;
		state->msgcnt = 0;
		return (1);

	case SCSI_NO_OP:
		break;

	case SCSI_SAVE_DATA_POINTER:
		/* expect another message */
		return (1);

	case SCSI_RESTORE_POINTERS:
		/*
		 * Need to do the following if resuming synchonous data in
		 * on an odd byte boundary.
		regs->asc_cnfg2 |= ASC_CNFG2_RFB;
		 */
		break;

	case SCSI_DISCONNECT:
		if (state->flags & DISCONN)
			goto abort;
		state->flags |= DISCONN;
		regs->asc_cmd = ASC_CMD_MSG_ACPT;
		readback(regs->asc_cmd);
		asc->script = &asc_scripts[SCRIPT_DISCONNECT];
		return (0);

	default:
		printf("%s: SCSI device %d: rejecting message 0x%x\n",
			asc->sc_dev.dv_xname, asc->target, msg);
	reject:
		/* request a message out before acknowledging this message */
		state->msg_out = SCSI_MESSAGE_REJECT;
		regs->asc_cmd = ASC_CMD_SET_ATN;
		readback(regs->asc_cmd);
	}

done:
	/* return to original script */
	regs->asc_cmd = ASC_CMD_MSG_ACPT;
	readback(regs->asc_cmd);
	if (!state->script) {
	abort:
#ifdef DEBUG
		asc_DumpLog("asc_msg_in");
#endif
		panic("asc_msg_in");
	}
	asc->script = state->script;
	state->script = (script_t *)0;
	return (0);
}

/* ARGSUSED */
static int
asc_disconnect(asc, status, ss, ir)
	register asc_softc_t asc;
	register int status, ss, ir;
{
	register State *state = &asc->st[asc->target];

#ifdef DIAGNOSTIC
	if (!(state->flags & DISCONN)) {
		printf("asc_disconnect: device %d: DISCONN not set!\n",
			asc->target);
	}
#endif /* DIAGNOSTIC */
	asc->target = -1;
	asc->state = ASC_STATE_RESEL;
	return (1);
}

#ifdef DEBUG
/*
 * Dump the log buffer.
 */
asc_DumpLog(str)
	char *str;
{
	register struct asc_log *lp;
	register u_int status;

	printf("asc: %s: cmd %x bn %d cnt %d\n", str, asc_debug_cmd,
		asc_debug_bn, asc_debug_sz);
	lp = asc_logp;
	do {
		status = lp->status;
		printf("asc%d tgt %d status %x ss %x ir %x cond %d:%x msg %x resid %d\n",
			status >> 24,
			lp->target,
			(status >> 16) & 0xFF,
			(status >> 8) & 0xFF,
			status & 0XFF,
			lp->state,
			asc_scripts[lp->state].condition,
			lp->msg, lp->resid);
		if (++lp >= &asc_log[NLOG])
			lp = asc_log;
	} while (lp != asc_logp);
}
#endif	/* DEBUG */

#endif	/* NASC > 0 */