xref: /src/sys/dev/ic/aic6360.c

/*	$NetBSD: aic6360.c,v 1.15 1994/11/29 17:56:49 mycroft Exp $	*/

/*
 * Copyright (c) 1994 Charles 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 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.
 *
 * Copyright (c) 1994 Jarle Greipsland
 * 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. 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.
 */

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

/* TODO list:
 * 1) Get the DMA stuff working.
 * 2) Get the iov/uio stuff working. Is this a good thing ???
 * 3) Get the synch stuff working.
 * 4) Rewrite it to use malloc for the acb structs instead of static alloc.?
 */

/*
 * A few customizable items:
 */

/* The SCSI ID of the host adapter/computer */
#define AIC_SCSI_HOSTID		7

/* Use doubleword transfers to/from SCSI chip.  Note: This requires
 * motherboard support.  Basicly, some motherboard chipsets are able to
 * split a 32 bit I/O operation into two 16 bit I/O operations,
 * transparently to the processor.  This speeds up some things, notably long
 * data transfers.
 */
#define AIC_USE_DWORDS		0

/* Allow disconnects?  Was mainly used in an early phase of the driver when
 * the message system was very flaky.  Should go away soon.
 */
#define AIC_ALLOW_DISCONNECT	1

/* Synchronous data transfers? */
#define AIC_USE_SYNCHRONOUS	0
#define AIC_SYNC_PERIOD 	200
#define AIC_SYNC_REQ_ACK_OFS 	8

/* Wide data transfers? */
#define	AIC_USE_WIDE		0
#define	AIC_MAX_WIDTH		0

/* Max attempts made to transmit a message */
#define AIC_MSG_MAX_ATTEMPT	3 /* Not used now XXX */

/* Use DMA (else we do programmed I/O using string instructions) (not yet!)*/
#define AIC_USE_EISA_DMA	0
#define AIC_USE_ISA_DMA		0

/* How to behave on the (E)ISA bus when/if DMAing (on<<4) + off in us */
#define EISA_BRST_TIM ((15<<4) + 1)	/* 15us on, 1us off */

/* Some spin loop parameters (essentially how long to wait some places)
 * The problem(?) is that sometimes we expect either to be able to transmit a
 * byte or to get a new one from the SCSI bus pretty soon.  In order to avoid
 * returning from the interrupt just to get yanked back for the next byte we
 * may spin in the interrupt routine waiting for this byte to come.  How long?
 * This is really (SCSI) device and processor dependent.  Tuneable, I guess.
 */
#define AIC_MSGI_SPIN		1 	/* Will spinwait upto ?ms for a new msg byte */
#define AIC_MSGO_SPIN		1

/* Include debug functions?  At the end of this file there are a bunch of
 * functions that will print out various information regarding queued SCSI
 * commands, driver state and chip contents.  You can call them from the
 * kernel debugger.  If you set AIC_DEBUG to 0 they are not included (the
 * kernel uses less memory) but you lose the debugging facilities.
 */
#define AIC_DEBUG		1

/* End of customizable parameters */

#if AIC_USE_EISA_DMA || AIC_USE_ISA_DMA
#error "I said not yet! Start paying attention... grumble"
#endif

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

#include <machine/pio.h>

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

#include <i386/isa/isavar.h>

/* Definitions, most of them has turned out to be unneccesary, but here they
 * are anyway.
 */

/*
 * Generic SCSI messages. For now we reject most of them.
 */
/* Messages (1 byte) */		     /* I/T M(andatory) or (O)ptional */
#define MSG_CMDCOMPLETE		0x00 /* M/M */
#define MSG_EXTENDED		0x01 /* O/O */
#define MSG_SAVEDATAPOINTER	0x02 /* O/O */
#define MSG_RESTOREPOINTERS	0x03 /* O/O */
#define MSG_DISCONNECT		0x04 /* O/O */
#define MSG_INITIATOR_DET_ERR	0x05 /* M/M */
#define MSG_ABORT		0x06 /* O/M */
#define MSG_MESSAGE_REJECT	0x07 /* M/M */
#define MSG_NOOP		0x08 /* M/M */
#define MSG_PARITY_ERROR	0x09 /* M/M */
#define MSG_LINK_CMD_COMPLETE	0x0a /* O/O */
#define MSG_LINK_CMD_COMPLETEF	0x0b /* O/O */
#define MSG_BUS_DEV_RESET	0x0c /* O/M */
#define MSG_ABORT_TAG		0x0d /* O/O */
#define MSG_CLEAR_QUEUE		0x0e /* O/O */
#define MSG_INIT_RECOVERY	0x0f /* O/O */
#define MSG_REL_RECOVERY	0x10 /* O/O */
#define MSG_TERM_IO_PROC	0x11 /* O/O */

/* Messages (2 byte) */
#define MSG_SIMPLE_Q_TAG	0x20 /* O/O */
#define MSG_HEAD_OF_Q_TAG	0x21 /* O/O */
#define MSG_ORDERED_Q_TAG	0x22 /* O/O */
#define MSG_IGN_WIDE_RESIDUE	0x23 /* O/O */

/* Identify message */
#define MSG_IDENTIFY(lun) ((AIC_ALLOW_DISCONNECT ? 0xc0 : 0x80)|((lun) & 0x7))
#define MSG_ISIDENT(m)		((m) & 0x80)

/* Extended messages (opcode) */
#define MSG_EXT_SDTR		0x01
#define	MSG_EXT_WDTR		0x03

/* SCSI Status codes */
#define ST_GOOD			0x00
#define ST_CHKCOND		0x02
#define ST_CONDMET		0x04
#define ST_BUSY			0x08
#define ST_INTERMED		0x10
#define ST_INTERMED_CONDMET	0x14
#define ST_RESERVATION_CONFLICT	0x18
#define ST_CMD_TERM		0x22
#define ST_QUEUE_FULL		0x28

#define ST_MASK			0x3e /* bit 0,6,7 is reserved */

/* AIC6360 definitions */
#define SCSISEQ		(iobase + 0x00) /* SCSI sequence control */
#define SXFRCTL0	(iobase + 0x01) /* SCSI transfer control 0 */
#define SXFRCTL1	(iobase + 0x02) /* SCSI transfer control 1 */
#define SCSISIGI	(iobase + 0x03) /* SCSI signal in */
#define SCSISIGO	(iobase + 0x03) /* SCSI signal out */
#define SCSIRATE	(iobase + 0x04) /* SCSI rate control */
#define SCSIID		(iobase + 0x05) /* SCSI ID */
#define SELID		(iobase + 0x05) /* Selection/Reselection ID */
#define SCSIDAT		(iobase + 0x06) /* SCSI Latched Data */
#define SCSIBUS		(iobase + 0x07) /* SCSI Data Bus*/
#define STCNT0		(iobase + 0x08) /* SCSI transfer count */
#define STCNT1		(iobase + 0x09)
#define STCNT2		(iobase + 0x0a)
#define CLRSINT0	(iobase + 0x0b) /* Clear SCSI interrupts 0 */
#define SSTAT0		(iobase + 0x0b) /* SCSI interrupt status 0 */
#define CLRSINT1	(iobase + 0x0c) /* Clear SCSI interrupts 1 */
#define SSTAT1		(iobase + 0x0c) /* SCSI status 1 */
#define SSTAT2		(iobase + 0x0d) /* SCSI status 2 */
#define SCSITEST	(iobase + 0x0e) /* SCSI test control */
#define SSTAT3		(iobase + 0x0e) /* SCSI status 3 */
#define CLRSERR		(iobase + 0x0f) /* Clear SCSI errors */
#define SSTAT4		(iobase + 0x0f) /* SCSI status 4 */
#define SIMODE0		(iobase + 0x10) /* SCSI interrupt mode 0 */
#define SIMODE1		(iobase + 0x11) /* SCSI interrupt mode 1 */
#define DMACNTRL0	(iobase + 0x12) /* DMA control 0 */
#define DMACNTRL1	(iobase + 0x13) /* DMA control 1 */
#define DMASTAT		(iobase + 0x14) /* DMA status */
#define FIFOSTAT	(iobase + 0x15) /* FIFO status */
#define DMADATA		(iobase + 0x16) /* DMA data */
#define DMADATAL	(iobase + 0x16) /* DMA data low byte */
#define DMADATAH	(iobase + 0x17) /* DMA data high byte */
#define BRSTCNTRL	(iobase + 0x18) /* Burst Control */
#define DMADATALONG	(iobase + 0x18)
#define PORTA		(iobase + 0x1a) /* Port A */
#define PORTB		(iobase + 0x1b) /* Port B */
#define REV		(iobase + 0x1c) /* Revision (001 for 6360) */
#define STACK		(iobase + 0x1d) /* Stack */
#define TEST		(iobase + 0x1e) /* Test register */
#define ID		(iobase + 0x1f) /* ID register */

#define IDSTRING "(C)1991ADAPTECAIC6360           "

/* What all the bits do */

/* SCSISEQ */
#define TEMODEO		0x80
#define ENSELO		0x40
#define ENSELI		0x20
#define ENRESELI	0x10
#define ENAUTOATNO	0x08
#define ENAUTOATNI	0x04
#define ENAUTOATNP	0x02
#define SCSIRSTO	0x01

/* SXFRCTL0 */
#define SCSIEN		0x80
#define DMAEN		0x40
#define CHEN		0x20
#define CLRSTCNT	0x10
#define SPIOEN		0x08
#define CLRCH		0x02

/* SXFRCTL1 */
#define BITBUCKET	0x80
#define SWRAPEN		0x40
#define ENSPCHK		0x20
#define STIMESEL1	0x10
#define STIMESEL0	0x08
#define STIMO_256ms	0x00
#define STIMO_128ms	0x08
#define STIMO_64ms	0x10
#define STIMO_32ms	0x18
#define ENSTIMER	0x04
#define BYTEALIGN	0x02

/* SCSISIGI */
#define CDI		0x80
#define IOI		0x40
#define MSGI		0x20
#define ATNI		0x10
#define SELI		0x08
#define BSYI		0x04
#define REQI		0x02
#define ACKI		0x01

/* Important! The 3 most significant bits of this register, in initiator mode,
 * represents the "expected" SCSI bus phase and can be used to trigger phase
 * mismatch and phase change interrupts.  But more important:  If there is a
 * phase mismatch the chip will not transfer any data!  This is actually a nice
 * feature as it gives us a bit more control over what is happening when we are
 * bursting data (in) through the FIFOs and the phase suddenly changes from
 * DATA IN to STATUS or MESSAGE IN.  The transfer will stop and wait for the
 * proper phase to be set in this register instead of dumping the bits into the
 * FIFOs.
 */
/* SCSISIGO */
#define CDO		0x80
#define CDEXP		(CDO)
#define IOO		0x40
#define IOEXP		(IOO)
#define MSGO		0x20
#define MSGEXP		(MSGO)
#define ATNO		0x10
#define SELO		0x08
#define BSYO		0x04
#define REQO		0x02
#define ACKO		0x01

/* Information transfer phases */
#define PH_DOUT		(0)
#define PH_DIN		(IOI)
#define PH_CMD		(CDI)
#define PH_STAT		(CDI|IOI)
#define PH_MSGO		(MSGI|CDI)
#define PH_MSGI		(MSGI|CDI|IOI)

#define PH_MASK		0xe0

/* Some pseudo phases for getphase()*/
#define PH_BUSFREE	0x100	/* (Re)Selection no longer valid */
#define PH_INVALID	0x101	/* (Re)Selection valid, but no REQ yet */
#define PH_PSBIT	0x100	/* "pseudo" bit */

/* SCSIRATE */
#define SXFR2		0x40
#define SXFR1		0x20
#define SXFR0		0x10
#define SOFS3		0x08
#define SOFS2		0x04
#define SOFS1		0x02
#define SOFS0		0x01

/* SCSI ID */
#define OID2		0x40
#define OID1		0x20
#define OID0		0x10
#define OID_S		4	/* shift value */
#define TID2		0x04
#define TID1		0x02
#define TID0		0x01
#define SCSI_ID_MASK	0x7

/* SCSI selection/reselection ID (both target *and* initiator) */
#define SELID7		0x80
#define SELID6		0x40
#define SELID5		0x20
#define SELID4		0x10
#define SELID3		0x08
#define SELID2		0x04
#define SELID1		0x02
#define SELID0		0x01

/* CLRSINT0                      Clears what? (interrupt and/or status bit) */
#define SETSDONE	0x80
#define CLRSELDO	0x40	/* I */
#define CLRSELDI	0x20	/* I+ */
#define CLRSELINGO	0x10	/* I */
#define CLRSWRAP	0x08	/* I+S */
#define CLRSDONE	0x04	/* I+S */
#define CLRSPIORDY	0x02	/* I */
#define CLRDMADONE	0x01	/* I */

/* SSTAT0                          Howto clear */
#define TARGET		0x80
#define SELDO		0x40	/* Selfclearing */
#define SELDI		0x20	/* Selfclearing when CLRSELDI is set */
#define SELINGO		0x10	/* Selfclearing */
#define SWRAP		0x08	/* CLRSWAP */
#define SDONE		0x04	/* Not used in initiator mode */
#define SPIORDY		0x02	/* Selfclearing (op on SCSIDAT) */
#define DMADONE		0x01	/* Selfclearing (all FIFOs empty & T/C */

/* CLRSINT1                      Clears what? */
#define CLRSELTIMO	0x80	/* I+S */
#define CLRATNO		0x40
#define CLRSCSIRSTI	0x20	/* I+S */
#define CLRBUSFREE	0x08	/* I+S */
#define CLRSCSIPERR	0x04	/* I+S */
#define CLRPHASECHG	0x02	/* I+S */
#define CLRREQINIT	0x01	/* I+S */

/* SSTAT1                       How to clear?  When set?*/
#define SELTO		0x80	/* C		select out timeout */
#define ATNTARG		0x40	/* Not used in initiator mode */
#define SCSIRSTI	0x20	/* C		RST asserted */
#define PHASEMIS	0x10	/* Selfclearing */
#define BUSFREE		0x08	/* C		bus free condition */
#define SCSIPERR	0x04	/* C		parity error on inbound data */
#define PHASECHG	0x02	/* C	     phase in SCSISIGI doesn't match */
#define REQINIT		0x01	/* C or ACK	asserting edge of REQ */

/* SSTAT2 */
#define SOFFSET		0x20
#define SEMPTY		0x10
#define SFULL		0x08
#define SFCNT2		0x04
#define SFCNT1		0x02
#define SFCNT0		0x01

/* SCSITEST */
#define SCTESTU		0x08
#define SCTESTD		0x04
#define STCTEST		0x01

/* SSTAT3 */
#define SCSICNT3	0x80
#define SCSICNT2	0x40
#define SCSICNT1	0x20
#define SCSICNT0	0x10
#define OFFCNT3		0x08
#define OFFCNT2		0x04
#define OFFCNT1		0x02
#define OFFCNT0		0x01

/* CLRSERR */
#define CLRSYNCERR	0x04
#define CLRFWERR	0x02
#define CLRFRERR	0x01

/* SSTAT4 */
#define SYNCERR		0x04
#define FWERR		0x02
#define FRERR		0x01

/* SIMODE0 */
#define ENSELDO		0x40
#define ENSELDI		0x20
#define ENSELINGO	0x10
#define	ENSWRAP		0x08
#define ENSDONE		0x04
#define ENSPIORDY	0x02
#define ENDMADONE	0x01

/* SIMODE1 */
#define ENSELTIMO	0x80
#define ENATNTARG	0x40
#define ENSCSIRST	0x20
#define ENPHASEMIS	0x10
#define ENBUSFREE	0x08
#define ENSCSIPERR	0x04
#define ENPHASECHG	0x02
#define ENREQINIT	0x01

/* DMACNTRL0 */
#define ENDMA		0x80
#define B8MODE		0x40
#define DMA		0x20
#define DWORDPIO	0x10
#define WRITE		0x08
#define INTEN		0x04
#define RSTFIFO		0x02
#define SWINT		0x01

/* DMACNTRL1 */
#define PWRDWN		0x80
#define ENSTK32		0x40
#define STK4		0x10
#define STK3		0x08
#define STK2		0x04
#define STK1		0x02
#define STK0		0x01

/* DMASTAT */
#define ATDONE		0x80
#define WORDRDY		0x40
#define INTSTAT		0x20
#define DFIFOFULL	0x10
#define DFIFOEMP	0x08
#define DFIFOHF		0x04
#define DWORDRDY	0x02

/* BRSTCNTRL */
#define BON3		0x80
#define BON2		0x40
#define BON1		0x20
#define BON0		0x10
#define BOFF3		0x08
#define BOFF2		0x04
#define BOFF1		0x02
#define BOFF0		0x01

/* TEST */
#define BOFFTMR		0x40
#define BONTMR		0x20
#define STCNTH		0x10
#define STCNTM		0x08
#define STCNTL		0x04
#define SCSIBLK		0x02
#define DMABLK		0x01


#define orreg(reg, val)   outb((reg), inb(reg)| (val))
#define andreg(reg, val)  outb((reg), inb(reg)& (val))
#define nandreg(reg, val) outb((reg), inb(reg)&~(val))



/* Grabbed from Julians SCSI aha-drivers */
#ifdef	DDB
int	Debugger();
#else	DDB
#define	Debugger() panic("should call debugger here (aic6360.c)")
#endif	DDB

typedef u_long physaddr;

struct aic_dma_seg {
	physaddr	addr;
	long		len;
};

extern int delaycount;
#define FUDGE(X)	((X)>>1) 	/* get 1 ms spincount */
#define MINIFUDGE(X)	((X)>>4) 	/* get (approx) 125us spincount */
#define AIC_NSEG	16
#define NUM_CONCURRENT	7	/* Only one per target for now */

/*
 * ACB. Holds additional information for each SCSI command Comments: We
 * need a separate scsi command block because we may need to overwrite it
 * with a request sense command.  Basicly, we refrain from fiddling with
 * the scsi_xfer struct (except do the expected updating of return values).
 * We'll generally update: xs->{flags,resid,error,sense,status} and
 * occasionally xs->retries.
 */
struct acb {
	TAILQ_ENTRY(acb) chain;
	struct scsi_xfer *xs;	/* SCSI xfer ctrl block from above */
	int		flags;	/* Status */
#define ACB_FREE	0x00
#define ACB_ACTIVE	0x01
#define ACB_DONE	0x04
#define ACB_CHKSENSE	0x08
/*	struct aic_dma_seg dma[AIC_NSEG]; /* Physical addresses+len */
	struct scsi_generic cmd;  /* SCSI command block */
	int	 clen;
	u_char	*dp;		/* Saved data pointer */
	int	 dleft;		/* Residue */
	int 	 stat;		/* SCSI status byte */
};

/*
 * Some info about each (possible) target on the SCSI bus.  This should
 * probably have been a "per target+lunit" structure, but we'll leave it at
 * this for now.  Is there a way to reliably hook it up to sc->fordriver??
 */
struct aic_tinfo {
	int	cmds;		/* #commands processed */
	int	dconns;		/* #disconnects */
	int	touts;		/* #timeouts */
	int	perrs;		/* #parity errors */
	int	senses;		/* #request sense commands sent */
	ushort	lubusy;		/* What local units/subr. are busy? */
	u_char  flags;
#define DO_SYNC		0x01	/* (Re)Negotiate synchronous options */
#define	DO_WIDE		0x02	/* (Re)Negotiate wide options */
	u_char  period;		/* Period suggestion */
	u_char  offset;		/* Offset suggestion */
	u_char	width;		/* Width suggestion */
	u_char  syncdata;	/* True negotiated synch parameters */
} tinfo_t;

struct aic_softc { /* One of these per adapter */
	/* Auto config stuff */
	struct device 	sc_dev;	/* This one has to go first! */
	struct isadev	sc_id;
	struct intrhand sc_ih;
	struct scsi_link sc_link;	/* prototype for subdevs */
	int		id_irq;		/* IRQ on the EISA bus */
	int		id_drq;		/* DRQ on the EISA bus */
	int		iobase;		/* Base I/O port */
	/* Lists of command blocks */
	TAILQ_HEAD(acb_list, acb) free_list, ready_list, nexus_list;
	struct acb *nexus;	/* current command */
	/* Command blocks and target info */
	struct acb acb[NUM_CONCURRENT];
	struct aic_tinfo tinfo[8];
	/* Data about the current nexus (updated for every cmd switch) */
	u_char	*dp;		/* Current data pointer */
	int	 dleft;		/* Data bytes left to transfer */
	u_char	*cp;		/* Current command pointer */
	int	 cleft;		/* Command bytes left to transfer */
	/* Adapter state */
	short	 phase;		/* Copy of what bus phase we are in */
	short	 prevphase;	/* Copy of what bus phase we were in */
	short	 state;		/* State applicable to the adapter */
#define AIC_IDLE	1
#define AIC_SELECTING	2	/* SCSI command is arbiting  */
#define AIC_RESELECTED	3	/* Has been reselected */
#define AIC_CONNECTED	4	/* Actively using the SCSI bus */
#define AIC_CLEANING	5
	short	 flags;
#define AIC_DROP_MSGI	0x01	/* Discard all msgs (parity err detected) */
#define AIC_DOINGDMA	0x02	/* The FIFO data path is active! */
#define AIC_BUSFREE_OK	0x04	/* Bus free phase is OK. */
	/* Debugging stuff */
#define AIC_HSIZE 8
	u_char	progress;	/* Set if interrupt has achieved progress */
	/* Message stuff */
	u_char	msgpriq;	/* Messages we want to send */
	u_char	msgoutq;	/* Messages sent during last MESSAGE OUT */
	u_char	msgout;		/* Message last transmitted */
#define SEND_DEV_RESET		0x01
#define SEND_PARITY_ERROR	0x02
#define SEND_ABORT		0x04
#define SEND_REJECT		0x08
#define SEND_INIT_DET_ERR	0x10
#define SEND_IDENTIFY  		0x20
#define SEND_SDTR		0x40
#define	SEND_WDTR		0x80
#define AIC_MAX_MSG_LEN 8
	u_char  omess[AIC_MAX_MSG_LEN];	/* Scratch area for messages */
	u_char	*omp;		/* Message pointer (for multibyte messages) */
	u_char	imess[AIC_MAX_MSG_LEN];
	u_char	*imp;		/* Message pointer (for multibyte messages) */
};

#if AIC_DEBUG
#define AIC_SHOWACBS	0x01
#define AIC_SHOWINTS	0x02
#define AIC_SHOWCMDS	0x04
#define AIC_SHOWMISC	0x08
#define AIC_SHOWTRACE	0x10
#define AIC_SHOWSTART	0x20
#define AIC_DOBREAK	0x40
int aic_debug = 0x00; /* AIC_SHOWSTART|AIC_SHOWMISC|AIC_SHOWTRACE; /**/
#define	AIC_PRINT(b, s)	do {if ((aic_debug & (b)) != 0) printf s;} while (0)
#define	AIC_BREAK()	do {if ((aic_debug & AIC_DOBREAK) != 0) Debugger();} while (0)
#else
#define	AIC_PRINT(b, s)
#define	AIC_BREAK()
#endif

#define AIC_ACBS(s)	AIC_PRINT(AIC_SHOWACBS, s)
#define AIC_INTS(s)	AIC_PRINT(AIC_SHOWINTS, s)
#define AIC_CMDS(s)	AIC_PRINT(AIC_SHOWCMDS, s)
#define AIC_MISC(s)	AIC_PRINT(AIC_SHOWMISC, s)
#define AIC_TRACE(s)	AIC_PRINT(AIC_SHOWTRACE, s)
#define AIC_START(s)	AIC_PRINT(AIC_SHOWSTART, s)

int	aicprobe	__P((struct device *, void *, void *));
void	aicattach	__P((struct device *, struct device *, void *));
void	aic_minphys	__P((struct buf *));
u_int	aic_adapter_info __P((struct aic_softc *));
int	aicintr		__P((struct aic_softc *));
void 	aic_init	__P((struct aic_softc *));
void	aic_done	__P((struct acb *));
int	aic_scsi_cmd	__P((struct scsi_xfer *));
int	aic_poll	__P((struct aic_softc *, struct acb *));
void	aic_add_timeout __P((struct acb *, int));
void	aic_remove_timeout __P((struct acb *));
void	aic_timeout	__P((void *arg));
int	aic_find	__P((struct aic_softc *));
void	aic_sched	__P((struct aic_softc *));
void	aic_scsi_reset	__P((struct aic_softc *));
#if AIC_DEBUG
void	aic_print_active_acb();
void	aic_dump_driver();
void	aic_dump6360();
#endif

/* Linkup to the rest of the kernel */
struct cfdriver aiccd = {
	NULL, "aic", aicprobe, aicattach, DV_DULL, sizeof(struct aic_softc)
};

struct scsi_adapter aic_switch = {
	aic_scsi_cmd,
	aic_minphys,
	0,
	0,
	aic_adapter_info,
	"aic"
};

struct scsi_device aic_dev = {
	NULL,			/* Use default error handler */
	NULL,			/* have a queue, served by this */
	NULL,			/* have no async handler */
	NULL,			/* Use default 'done' routine */
	"aic",
	0
};

/*
 * INITIALIZATION ROUTINES (probe, attach ++)
 */

/*
 * aicprobe: probe for AIC6360 SCSI-controller
 * returns non-zero value if a controller is found.
 */
int
aicprobe(parent, match, aux)
	struct device *parent;
	void *match, *aux;
{
	struct aic_softc *aic = match;
	struct isa_attach_args *ia = aux;
	int i, len, ic;

#ifdef NEWCONFIG
	if (ia->ia_iobase == IOBASEUNK)
		return 0;
#endif
	aic->iobase = ia->ia_iobase;
	if (aic_find(aic) != 0)
		return 0;
#ifdef NEWCONFIG
	if (ia->ia_irq == IRQUNK)
		ia->ia_irq = aic->aic_int;
	else if (ia->ia_irq != aic->aic_int) {
		printf("aic%d: irq mismatch, %x != %x\n",
		    aic->sc_dev.dv_unit, ia->ia_irq, aic->aic_int);
		return 0;
	}

	if (ia->ia_drq == DRQUNK)
		ia->ia_drq = aic->aic_dma;
	else if (ia->ia_drq != aic->aic_dma) {
		printf("aic%d: drq mismatch, %x != %x\n",
		    aic->sc_dev.dv_unit, ia->ia_drq, aic->aic_dma);
		return 0;
	}
#endif
	ia->ia_msize = 0;
	ia->ia_iosize = 0x20;
	return 1;
}

/* Do the real search-for-device.
 * Prerequisite: aic->iobase should be set to the proper value
 */
int
aic_find(aic)
	struct aic_softc *aic;
{
	int iobase = aic->iobase;
	char chip_id[sizeof(IDSTRING)];	/* For chips that support it */
	char *start;
	int i;

	/* Remove aic6360 from possible powerdown mode */
	outb(DMACNTRL0, 0);

	/* Thanks to mark (at) aggregate.com for the new method for detecting
	 * whether the chip is present or not.  Bonus: may also work for
	 * the AIC-6260!
 	 */
	AIC_TRACE(("aic: probing for aic-chip at port 0x%x\n",(int)iobase));
 	/*
 	 * Linux also init's the stack to 1-16 and then clears it,
     	 *  6260's don't appear to have an ID reg - mpg
 	 */
	/* Push the sequence 0,1,..,15 on the stack */
#define STSIZE 16
	outb(DMACNTRL1, 0);	/* Reset stack pointer */
	for (i = 0; i < STSIZE; i++)
		outb(STACK, i);

	/* See if we can pull out the same sequence */
	outb(DMACNTRL1, 0);
 	for (i = 0; i < STSIZE && inb(STACK) == i; i++)
		;
	if (i != STSIZE) {
		AIC_START(("STACK futzed at %d.\n", i));
		return ENXIO;
	}

	/* See if we can pull the id string out of the ID register,
	 * now only used for informational purposes.
	 */
	bzero(chip_id, sizeof(chip_id));
	insb(ID, chip_id, sizeof(IDSTRING)-1);
	AIC_START(("AIC found at 0x%x ", (int)aic->iobase));
	AIC_START(("ID: %s ",chip_id));
	AIC_START(("chip revision %d\n",(int)inb(REV)));
	return 0;
}

int
aicprint()
{
}

/*
 * Attach the AIC6360, fill out some high and low level data structures
 */
void
aicattach(parent, self, aux)
	struct device *parent, *self;
	void *aux;
{
	struct isa_attach_args *ia = aux;
	struct aic_softc *aic = (void *)self;

	AIC_TRACE(("aicattach  "));
	aic->state = 0;
	aic_init(aic);	/* Init chip and driver */

	/*
	 * Fill in the prototype scsi_link
	 */
	aic->sc_link.adapter_softc = aic;
	aic->sc_link.adapter_targ = AIC_SCSI_HOSTID;
	aic->sc_link.adapter = &aic_switch;
	aic->sc_link.device = &aic_dev;
	printf("\n");

#ifdef NEWCONFIG
	isa_establish(&aic->sc_id, &aic->sc_dev);
#endif
	aic->sc_ih.ih_fun = aicintr;
	aic->sc_ih.ih_arg = aic;
	aic->sc_ih.ih_level = IPL_BIO;
	intr_establish(ia->ia_irq, &aic->sc_ih);

	config_found(self, &aic->sc_link, aicprint);
}


/* Initialize AIC6360 chip itself
 * The following conditions should hold:
 * aicprobe should have succeeded, i.e. the iobase address in aic_softc must
 * be valid.
 */
static void
aic6360_reset(aic)
	struct aic_softc *aic;
{
	int iobase = aic->iobase;

	outb(SCSITEST, 0);	/* Doc. recommends to clear these two */
	outb(TEST, 0);		/* registers before operations commence */

	/* Reset SCSI-FIFO and abort any transfers */
	outb(SXFRCTL0, CHEN|CLRCH|CLRSTCNT);

	/* Reset DMA-FIFO */
	outb(DMACNTRL0, RSTFIFO);
	outb(DMACNTRL1, 0);

	outb(SCSISEQ, 0);	/* Disable all selection features */
	outb(SXFRCTL1, 0);

	outb(SIMODE0, 0x00);		/* Disable some interrupts */
	outb(CLRSINT0, 0x7f);	/* Clear a slew of interrupts */

	outb(SIMODE1, 0x00);		/* Disable some more interrupts */
	outb(CLRSINT1, 0xef);	/* Clear another slew of interrupts */

	outb(SCSIRATE, 0);	/* Disable synchronous transfers */

	outb(CLRSERR, 0x07);	/* Haven't seen ant errors (yet) */

	outb(SCSIID, AIC_SCSI_HOSTID << OID_S); /* Set our SCSI-ID */
	outb(BRSTCNTRL, EISA_BRST_TIM);
}

/* Pull the SCSI RST line for 500 us */
void
aic_scsi_reset(aic)
	struct aic_softc *aic;
{
	int iobase = aic->iobase;

	outb(SCSISEQ, SCSIRSTO);
	delay(500);
	outb(SCSISEQ, 0);
	delay(50);
}

/*
 * Initialize aic SCSI driver, also (conditonally) reset the SCSI bus.
 * The reinitialization is still buggy (e.g. on SCSI resets).
 */
void
aic_init(aic)
	struct aic_softc *aic;
{
	int iobase = aic->iobase;
	struct acb *acb;
	int r;

	aic_scsi_reset(aic);
	aic6360_reset(aic);	/* Clean up our own hardware */

/*XXX*/	/* If not the first time (probably a reset condition),
	 * we should clean queues with active commands
	 */
	if (aic->state == 0) {	/* First time through */
		TAILQ_INIT(&aic->ready_list);
		TAILQ_INIT(&aic->nexus_list);
		TAILQ_INIT(&aic->free_list);
		aic->nexus = 0;
		acb = aic->acb;
		bzero(acb, sizeof(aic->acb));
		for (r = 0; r < sizeof(aic->acb) / sizeof(*acb); r++) {
			TAILQ_INSERT_TAIL(&aic->free_list, acb, chain);
			acb++;
		}
		bzero(&aic->tinfo, sizeof(aic->tinfo));
	} else {
		aic->state = AIC_CLEANING;
		if ((acb = aic->nexus) != NULL) {
			acb->xs->error = XS_DRIVER_STUFFUP;
			untimeout(aic_timeout, acb);
			aic_done(acb);
		}
		while (acb = aic->nexus_list.tqh_first) {
			acb->xs->error = XS_DRIVER_STUFFUP;
			untimeout(aic_timeout, acb);
			aic_done(acb);
		}
	}

	aic->phase = aic->prevphase = PH_INVALID;
	for (r = 0; r < 8; r++) {
		struct aic_tinfo *ti = &aic->tinfo[r];

		ti->flags = 0;
		if (AIC_USE_SYNCHRONOUS) {
			ti->flags |= DO_SYNC;
			ti->period = AIC_SYNC_PERIOD;
			ti->offset = AIC_SYNC_REQ_ACK_OFS;
		}
		if (AIC_USE_WIDE) {
			ti->flags |= DO_WIDE;
			ti->width = AIC_MAX_WIDTH;
		}
		ti->syncdata = 0;
	}

	aic->state = AIC_IDLE;
	outb(DMACNTRL0, INTEN);
}

void
aic_free_acb(aic, acb, flags)
	struct aic_softc *aic;
	struct acb *acb;
	int flags;
{
	int s;

	if ((flags & SCSI_NOMASK) == 0)
		s = splbio();

	acb->flags = ACB_FREE;
	TAILQ_INSERT_HEAD(&aic->free_list, acb, chain);
	if (acb->chain.tqe_next == 0)
		wakeup(&aic->free_list);

	if ((flags & SCSI_NOMASK) == 0)
		splx(s);
}

struct acb *
aic_get_acb(aic, flags)
	struct aic_softc *aic;
	int flags;
{
	int s;
	struct acb *acb;

	/* Get a aic command block */
	if ((flags & SCSI_NOMASK) == 0)
		s = splbio();

	while ((acb = aic->free_list.tqh_first) == NULL &&
	       (flags & SCSI_NOSLEEP) == 0)
		tsleep(&aic->free_list, PRIBIO, "aicacb", 0);
	if (acb) {
		TAILQ_REMOVE(&aic->free_list, acb, chain);
		acb->flags = ACB_ACTIVE;
	}

	if ((flags & SCSI_NOMASK) == 0)
		splx(s);

	return acb;
}

/*
 * DRIVER FUNCTIONS CALLABLE FROM HIGHER LEVEL DRIVERS
 */

/*
 * Expected sequence:
 * 1) Command inserted into ready list
 * 2) Command selected for execution
 * 3) Command won arbitration and has selected target device
 * 4) Send message out (identify message, eventually also sync.negotiations)
 * 5) Send command
 * 5a) Receive disconnect message, disconnect.
 * 5b) Reselected by target
 * 5c) Receive identify message from target.
 * 6) Send or receive data
 * 7) Receive status
 * 8) Receive message (command complete etc.)
 * 9) If status == SCSI_CHECK construct a synthetic request sense SCSI cmd.
 *    Repeat 2-8 (no disconnects please...)
 */

/*
 * Start a SCSI-command
 * This function is called by the higher level SCSI-driver to queue/run
 * SCSI-commands.
 */
int
aic_scsi_cmd(xs)
	struct scsi_xfer *xs;
{
	struct scsi_link *sc = xs->sc_link;
	struct aic_softc *aic = sc->adapter_softc;
	struct acb 	*acb;
	int s, flags;
	int iobase = aic->iobase;

	AIC_TRACE(("aic_scsi_cmd  "));
	AIC_CMDS(("[0x%x, %d]->%d ", (int)xs->cmd->opcode, xs->cmdlen,
	    sc->target));

	flags = xs->flags;

	if ((acb = aic_get_acb(aic, flags)) == NULL) {
		xs->error = XS_DRIVER_STUFFUP;
		return TRY_AGAIN_LATER;
	}

	/* Initialize acb */
	acb->xs = xs;
	bcopy(xs->cmd, &acb->cmd, xs->cmdlen);
	acb->clen = xs->cmdlen;
	acb->dp = xs->data;
	acb->dleft = xs->datalen;
	acb->stat = 0;

	if ((flags & SCSI_NOMASK) == 0)
		s = splbio();

	TAILQ_INSERT_TAIL(&aic->ready_list, acb, chain);
	timeout(aic_timeout, acb, (xs->timeout*hz)/1000);

	if (aic->state == AIC_IDLE)
		aic_sched(aic);

	if ((flags & SCSI_NOMASK) == 0) { /* Almost done. Wait outside */
		splx(s);
		AIC_MISC(("SUCCESSFULLY_QUEUED"));
		return SUCCESSFULLY_QUEUED;
	}

	/* Not allowed to use interrupts, use polling instead */
	return aic_poll(aic, acb);
}

/*
 * Adjust transfer size in buffer structure
 */
void
aic_minphys(bp)
	struct buf *bp;
{

	AIC_TRACE(("aic_minphys  "));
	if (bp->b_bcount > (AIC_NSEG << PGSHIFT))
		bp->b_bcount = (AIC_NSEG << PGSHIFT);
}


u_int
aic_adapter_info(aic)
	struct aic_softc *aic;
{

	AIC_TRACE(("aic_adapter_info  "));
	return 2;		/* One outstanding command per target */
}

/*
 * Used when interrupt driven I/O isn't allowed, e.g. during boot.
 */
int
aic_poll(aic, acb)
	struct aic_softc *aic;
	struct acb *acb;
{
	register int iobase = aic->iobase;
	struct scsi_xfer *xs = acb->xs;
	int count = xs->timeout * 10;

	AIC_TRACE(("aic_poll  "));
	while (count) {
		if ((inb(DMASTAT) & INTSTAT) != 0)
			aicintr(aic);
		if ((xs->flags & ITSDONE) != 0)
			break;
		delay(100);
		count--;
	}
	if (count == 0) {
		AIC_MISC(("aic_poll: timeout"));
		aic_timeout((caddr_t)acb);
	}
	if (xs->error)
		return HAD_ERROR;
	return COMPLETE;
}

/* LOW LEVEL SCSI UTILITIES */

/* Determine the SCSI bus phase, return either a real SCSI bus phase or some
 * pseudo phase we use to detect certain exceptions.  This one is a bit tricky.
 * The bits we peek at:
 * CDI, MSGI and DI is the 3 SCSI signals determining the bus phase.
 * These should be qualified by REQI high and ACKI low.
 * Also peek at SSTAT0[SELDO|SELDI] to detect a passing BUSFREE condition.
 * No longer detect SCSI RESET or PERR here.  They are tested for separately
 * in the interrupt handler.
 * Note: If an exception occur at some critical time during the phase
 * determination we'll most likely return something wildly erronous....
 */
static inline u_short
aicphase(aic)
	struct aic_softc *aic;
{
	register int iobase = aic->iobase;
	register u_char sstat0, sstat1, scsisig;

	sstat1 = inb(SSTAT1);	/* Look for REQINIT (REQ asserted) */
	scsisig = inb(SCSISIGI); /* Get the SCSI bus signals */
	sstat0 = inb(SSTAT0);	/* Get the selection valid status bits */

	if ((sstat0 & (SELDO|SELDI)) == 0)	/* Selection became invalid? */
		return PH_BUSFREE;

	/* Selection is still valid */
	if ((sstat1 & REQINIT) == 0) 		/* REQ not asserted ? */
		return PH_INVALID;

	/* REQ is asserted, (and ACK is not) */
	return (scsisig & PH_MASK);
}

/*
 * Start a selection.  This is used by aic_sched() to select an idle target,
 * and by aic_done() to immediately reselect a target to get sense information.
 */
void
aic_select(aic, target)
	struct aic_softc *aic;
	int target;
{
	int iobase = aic->iobase;

	outb(SCSIID, AIC_SCSI_HOSTID << OID_S | target);
	outb(SCSIRATE, aic->tinfo[target].syncdata);
	outb(SXFRCTL1, STIMO_256ms|ENSTIMER);
	/* Always enable reselections. */
	outb(SIMODE0, ENSELDI|ENSELDO);
	outb(SIMODE1, ENSCSIRST|ENSELTIMO);
	outb(SCSISEQ, ENRESELI|ENSELO|ENAUTOATNO);

	aic->state = AIC_SELECTING;
}

/*
 * Schedule a SCSI operation.  This has now been pulled out of the interrupt
 * handler so that we may call it from aic_scsi_cmd and aic_done.  This may
 * save us an unecessary interrupt just to get things going.  Should only be
 * called when state == AIC_IDLE and at bio pl.
 */
void
aic_sched(aic)
	register struct aic_softc *aic;
{
	int iobase = aic->iobase;
	struct acb *acb;
	struct scsi_link *sc;
	struct aic_tinfo *ti;

	/*
	 * Find first acb in ready queue that is for a target/lunit pair that
	 * is not busy.
	 */
	for (acb = aic->ready_list.tqh_first; acb; acb = acb->chain.tqe_next) {
		sc = acb->xs->sc_link;
		ti = &aic->tinfo[sc->target];
		if ((ti->lubusy & (1<<sc->lun)) == 0) {
			AIC_MISC(("selecting %d:%d  ", sc->target, sc->lun));
			TAILQ_REMOVE(&aic->ready_list, acb, chain);
			aic->nexus = acb;
			aic_select(aic, sc->target);
			return;
		} else
			AIC_MISC(("%d:%d busy\n", sc->target, sc->lun));
	}
	AIC_MISC(("idle  "));
	/* Nothing to start; just enable reselections and wait. */
	outb(SIMODE0, ENSELDI);
	outb(SIMODE1, ENSCSIRST);
	outb(SCSISEQ, ENRESELI);
}

/*
 * POST PROCESSING OF SCSI_CMD (usually current)
 */
void
aic_done(acb)
	struct acb *acb;
{
	struct scsi_xfer *xs = acb->xs;
	struct scsi_link *sc = xs->sc_link;
	struct aic_softc *aic = sc->adapter_softc;
	struct aic_tinfo *ti;

	AIC_TRACE(("aic_done  "));
	ti = &aic->tinfo[sc->target];

	/*
	 * Now, if we've come here with no error code, i.e. we've kept the
	 * initial XS_NOERROR, and the status code signals that we should
	 * check sense, we'll need to set up a request sense cmd block and
	 * push the command back into the ready queue *before* any other
	 * commands for this target/lunit, else we lose the sense info.
	 * We don't support chk sense conditions for the request sense cmd.
	 */
	if (xs->error == XS_NOERROR && (acb->flags & ACB_CHKSENSE) == 0) {
		if ((acb->stat & ST_MASK) == SCSI_CHECK) {
			struct scsi_sense *ss = (void *)&acb->cmd;

			AIC_MISC(("requesting sense  "));
			/* First, save the return values */
			xs->resid = acb->dleft;
			xs->status = acb->stat;
			/* Next, setup a request sense command block */
			bzero(ss, sizeof(*ss));
			ss->op_code = REQUEST_SENSE;
			ss->byte2 = sc->lun << 5;
			ss->length = sizeof(struct scsi_sense_data);
			acb->clen = sizeof(*ss);
			acb->dp = (char *)&xs->sense;
			acb->dleft = sizeof(struct scsi_sense_data);
			acb->flags = ACB_ACTIVE|ACB_CHKSENSE;
			ti->senses++;
			if (acb != aic->nexus) {
				ti->lubusy &= ~(1<<sc->lun);
				TAILQ_INSERT_HEAD(&aic->ready_list, acb, chain);
			} else
				aic_select(aic, sc->target);
			return;
		}
	}

	if ((xs->flags & SCSI_ERR_OK) != 0) {
		xs->resid = 0;
		xs->error = XS_NOERROR;
	} else if (xs->error == XS_NOERROR && (acb->flags & ACB_CHKSENSE) != 0) {
		xs->error = XS_SENSE;
	} else {
		xs->resid = acb->dleft;
	}
	xs->flags |= ITSDONE;

#if AIC_DEBUG
	if ((aic_debug & AIC_SHOWMISC) != 0) {
		if (xs->resid != 0)
			printf("resid=%d ", xs->resid);
		if (xs->error == XS_SENSE)
			printf("sense=0x%02x\n", xs->sense.error_code);
		else
			printf("error=%d\n", xs->error);
	}
#endif

	/*
	 * Remove the ACB from whatever queue it's on.  We have to do a bit of
	 * a hack to figure out which queue it's on.  Note that it is *not*
	 * necessary to cdr down the ready queue, but we must cdr down the
	 * nexus queue and see if it's there, so we can mark the unit as no
	 * longer busy.  This code is sickening, but it works.
	 */
	if (acb == aic->nexus) {
		ti->lubusy &= ~(1<<sc->lun);
		aic->state = AIC_IDLE;
		aic->nexus = NULL;
		aic_sched(aic);
	} else if (aic->ready_list.tqh_last == &acb->chain.tqe_next) {
		TAILQ_REMOVE(&aic->ready_list, acb, chain);
	} else {
		register struct acb *acb2;
		for (acb2 = aic->nexus_list.tqh_first; acb2;
		    acb2 = acb2->chain.tqe_next)
			if (acb2 == acb) {
				TAILQ_REMOVE(&aic->nexus_list, acb, chain);
				ti->lubusy &= ~(1<<sc->lun);
				/* XXXX Should we call aic_sched() here? */
				break;
			}
		if (acb2)
			;
		else if (acb->chain.tqe_next) {
			TAILQ_REMOVE(&aic->ready_list, acb, chain);
		} else {
			printf("%s: can't find matching acb\n",
			    aic->sc_dev.dv_xname);
			Debugger();
		}
	}

	aic_free_acb(aic, acb, xs->flags);
	ti->cmds++;
	scsi_done(xs);
}

/*
 * INTERRUPT/PROTOCOL ENGINE
 */

/* The message system:
 * This is a revamped message system that now should easier accomodate new
 * messages, if necessary.
 * Currently we accept these messages:
 * IDENTIFY (when reselecting)
 * COMMAND COMPLETE # (expect bus free after messages marked #)
 * NOOP
 * MESSAGE REJECT
 * SYNCHRONOUS DATA TRANSFER REQUEST
 * SAVE DATA POINTER
 * RESTORE POINTERS
 * DISCONNECT #
 *
 * We may send these messages in prioritized order:
 * BUS DEVICE RESET #		if SCSI_RESET & xs->flags (or in weird sits.)
 * MESSAGE PARITY ERROR		par. err. during MSGI
 * MESSAGE REJECT		If we get a message we don't know how to handle
 * ABORT #			send on errors
 * INITIATOR DETECTED ERROR	also on errors (SCSI2) (during info xfer)
 * IDENTIFY			At the start of each transfer
 * SYNCHRONOUS DATA TRANSFER REQUEST	if appropriate
 * NOOP				if nothing else fits the bill ...
 */

#define aic_sched_msgout(m) \
	do {					\
		if (aic->msgpriq == 0)		\
			orreg(SCSISIGO, ATNO);	\
		aic->msgpriq |= (m);		\
	} while (0)

#define IS1BYTEMSG(m) (((m) != 0x01 && (m) < 0x20) || (m) >= 0x80)
#define IS2BYTEMSG(m) (((m) & 0xf0) == 0x20)
#define ISEXTMSG(m) ((m) == 0x01)
/*
 * Precondition:
 * The SCSI bus is already in the MSGI phase and there is a message byte
 * on the bus, along with an asserted REQ signal.
 */
void
aic_msgin(aic)
	register struct aic_softc *aic;
{
	register int iobase = aic->iobase;
	int n;

	AIC_TRACE(("aic_msgin  "));
	aic->progress = 0;

	if (aic->prevphase == PH_MSGI) {
		/* This is a continuation of the previous message. */
		n = aic->imp - aic->imess;
		goto nextbyte;
	}

	/* This is a new MESSAGE IN phase.  Clean up our state. */
	aic->flags &= ~AIC_DROP_MSGI;

nextmsg:
	n = 0;
	aic->imp = &aic->imess[n];

nextbyte:
	/*
	 * Read a whole message, but don't ack the last byte.  If we reject the
	 * message, we have to assert ATN during the message transfer phase
	 * itself.
	 */
	for (;;) {
		do {
			aic->phase = aicphase(aic);
		} while (aic->phase == PH_INVALID);
		if (aic->phase != PH_MSGI) {
			/*
			 * Target left MESSAGE IN, probably because it
			 * a) noticed our ATN signal, or
			 * b) ran out of messages.
			 */
			goto out;
		}

		/* XXX parity */

		/* Gather incoming message bytes if needed. */
		if ((aic->flags & AIC_DROP_MSGI) == 0) {
			if (n >= AIC_MAX_MSG_LEN) {
				aic_sched_msgout(SEND_REJECT);
				aic->flags |= AIC_DROP_MSGI;
			} else {
				*aic->imp++ = inb(SCSIDAT);
				n++;
				/*
				 * This testing is suboptimal, but most
				 * messages will be of the one byte variety, so
				 * it should not affect performance
				 * significantly.
				 */
				if (IS1BYTEMSG(aic->imess[0]) && n == 1)
					break;
				if (IS2BYTEMSG(aic->imess[0]) && n == 2)
					break;
				if (ISEXTMSG(aic->imess[0]) && n >= 3 &&
				    n == aic->imess[1] + 2)
					break;
			}
		}

		/*
		 * If we reach this spot we're either:
		 * a) in the middle of a multi-byte message, or
		 * b) dropping bytes.
		 */
		outb(SXFRCTL0, CHEN|SPIOEN);
		/* Ack the last byte read. */
		(void) inb(SCSIDAT);
		outb(SXFRCTL0, CHEN);
	}

	aic->progress = 1;
	AIC_MISC(("n=%d imess=0x%02x  ", n, aic->imess[0]));

	/* We now have a complete message.  Parse it. */
	switch (aic->state) {
		struct acb *acb;
		struct scsi_link *sc;
		struct aic_tinfo *ti;
		int period, offset, width;
		u_char selid, target, lun;

	case AIC_CONNECTED:
		acb = aic->nexus;
		sc = acb->xs->sc_link;
		ti = &aic->tinfo[sc->target];

		switch (aic->imess[0]) {
		case MSG_CMDCOMPLETE:
			if (aic->dleft < 0) {
				printf("aic: %d extra bytes from %d:%d\n",
				       -aic->dleft, sc->target, sc->lun);
				acb->dleft = 0;
			}
			acb->xs->resid = acb->dleft = aic->dleft;
			aic->flags |= AIC_BUSFREE_OK;
#if 1 /* XXX defer till BUS FREE? */
			untimeout(aic_timeout, acb);
			delay(250);
			aic_done(acb);
#endif
			break;

		case MSG_PARITY_ERROR:
			/* Resend the last message. */
			aic_sched_msgout(aic->msgout);
			break;

		case MSG_MESSAGE_REJECT:
			AIC_MISC(("message rejected  "));
			switch (aic->msgout) {
			case SEND_IDENTIFY:
				ti->flags &= ~(DO_SYNC|DO_WIDE);
				ti->syncdata = 0;
				outb(SCSIRATE, ti->syncdata);
				/* ... */
				break;
			case SEND_SDTR:
				ti->flags &= ~DO_SYNC;
				ti->syncdata = 0;
				outb(SCSIRATE, ti->syncdata);
				break;
			case SEND_WDTR:
				ti->flags &= ~DO_WIDE;
				/* ... */
				break;
			case SEND_INIT_DET_ERR:
				aic_sched_msgout(SEND_ABORT);
				break;
			}
			break;

		case MSG_NOOP:
			break;

		case MSG_DISCONNECT:
			ti->dconns++;
			aic->state = AIC_IDLE;
			aic->nexus = NULL;
			TAILQ_INSERT_HEAD(&aic->nexus_list, acb, chain);
			aic->flags |= AIC_BUSFREE_OK;
			break;

		case MSG_SAVEDATAPOINTER:
			acb->dp = aic->dp;
			acb->dleft = aic->dleft;
			break;

		case MSG_RESTOREPOINTERS:
			aic->dp = acb->dp;
			aic->dleft = acb->dleft;
			aic->cp = (u_char *)&acb->cmd;
			aic->cleft = acb->clen;
			break;

		case MSG_EXTENDED:
			switch (aic->imess[2]) {
			case MSG_EXT_SDTR:
				if (aic->imess[1] != 3)
					goto reject;
				period = (aic->imess[3] * 4 + 49)/50 - 2;
				offset = aic->imess[4];
				if (offset == 0) {
					ti->flags &= ~DO_SYNC;
					ti->syncdata = 0;
					outb(SCSIRATE, ti->syncdata);
				} else if (period > 7) {
					/* Too slow for aic6360. Do asynch
					 * instead.  Renegotiate the deal.
					 */
					ti->period = 0;
					ti->offset = 0;
					aic_sched_msgout(SEND_SDTR);
				} else {
					ti->flags &= ~DO_SYNC;
					ti->syncdata = period<<4 | offset;
					outb(SCSIRATE, ti->syncdata);
				}
				break;

			case MSG_EXT_WDTR:
				if (aic->imess[1] != 2)
					goto reject;
				width = aic->imess[3];
				if (width == 0) {
					ti->flags &= ~DO_WIDE;
					/* ... */
				} else if (width > AIC_MAX_WIDTH) {
					ti->width = 0;
					aic_sched_msgout(SEND_WDTR);
				} else {
					ti->flags &= ~DO_WIDE;
					/* ... */
				}
				break;

			default:
				printf("aic at line %d: unrecognized MESSAGE IN; sending REJECT\n", __LINE__);
				AIC_BREAK();
				goto reject;
			}
			break;

		default:
			printf("aic at line %d: unrecognized MESSAGE IN; sending REJECT\n", __LINE__);
			AIC_BREAK();
		reject:
			aic_sched_msgout(SEND_REJECT);
			break;
		}
		break;

	case AIC_RESELECTED:
		if (!MSG_ISIDENT(aic->imess[0])) {
			printf("aic at line %d: reselect without IDENTIFY; sending DEVICE RESET\n", __LINE__);
			AIC_BREAK();
			goto reset;
		}

		/*
		 * The SCSI chip made a snapshot of the data bus while the
		 * reselection was being negotiated.  This enables us to
		 * determine which target did the reselect.
		 */
		selid = inb(SELID) & ~(1<<AIC_SCSI_HOSTID);
		if (selid & (selid - 1)) {
			printf("aic at line %d: reselect with invalid selid %02x; sending DEVICE RESET\n", __LINE__, selid);
			AIC_BREAK();
			goto reset;
		}

		/* Search wait queue for disconnected cmd
		 * The list should be short, so I haven't bothered with
		 * any more sophisticated structures than a simple
		 * singly linked list.
		 */
		target = ffs(selid) - 1;
		lun = aic->imess[0] & 0x07;
		for (acb = aic->nexus_list.tqh_first; acb != 0;
		     acb = acb->chain.tqe_next) {
			sc = acb->xs->sc_link;
			if (sc->target == target && sc->lun == lun)
				break;
		}
		if (acb == 0) {
			printf("aic at line %d: reselect from target %d lun %d with no nexus; sending DEVICE RESET\n", __LINE__, target, lun);
			AIC_BREAK();
			goto reset;
		}

		/* Make this nexus active again. */
		TAILQ_REMOVE(&aic->nexus_list, acb, chain);
		aic->state = AIC_CONNECTED;
		aic->nexus = acb;
		ti = &aic->tinfo[sc->target];
		ti->lubusy |= (1<<sc->lun);
		outb(SCSIRATE, ti->syncdata);

		/* Do an implicit RESTORE POINTERS. */
		aic->dp = acb->dp;
		aic->dleft = acb->dleft;
		aic->cp = (u_char *)&acb->cmd;
		aic->cleft = acb->clen;
		break;

	default:
		printf("aic at line %d: unexpected MESSAGE IN; sending DEVICE RESET\n", __LINE__);
		AIC_BREAK();
	reset:
		aic_sched_msgout(SEND_DEV_RESET);
		break;
	}

	outb(SXFRCTL0, CHEN|SPIOEN);
	/* Ack the last message byte. */
	(void) inb(SCSIDAT);
	outb(SXFRCTL0, CHEN);

	/* Go get the next message, if any. */
	goto nextmsg;

out:
	AIC_MISC(("n=%d imess=0x%02x  ", n, aic->imess[0]));
}


/* The message out (and in) stuff is a bit complicated:
 * If the target requests another message (sequence) without
 * having changed phase in between it really asks for a
 * retransmit, probably due to parity error(s).
 * The following messages can be sent:
 * IDENTIFY	   @ These 4 stem from SCSI command activity
 * SDTR		   @
 * WDTR		   @
 * DEV_RESET	   @
 * REJECT if MSGI doesn't make sense
 * PARITY_ERROR if parity error while in MSGI
 * INIT_DET_ERR if parity error while not in MSGI
 * ABORT if INIT_DET_ERR rejected
 * NOOP if asked for a message and there's nothing to send
 */
void
aic_msgout(aic)
	register struct aic_softc *aic;
{
	register int iobase = aic->iobase;
	struct acb *acb;
	struct aic_tinfo *ti;
	int n;

	AIC_TRACE(("aic_msgout  "));
	aic->progress = 0;

	/*
	 * Set ATN.  If we're just sending a trivial 1-byte message, we'll
	 * clear ATN later on anyway.
	 */
	outb(SCSISIGO, PH_MSGO|ATNO);
	/* Reset the FIFO. */
	outb(DMACNTRL0, RSTFIFO);
	/* Enable REQ/ACK protocol. */
	outb(SXFRCTL0, CHEN|SPIOEN);

	if (aic->prevphase == PH_MSGO) {
		if (aic->omp == aic->omess) {
			/*
			 * This is a retransmission.
			 *
			 * We get here if the target stayed in MESSAGE OUT
			 * phase.  Section 5.1.9.2 of the SCSI 2 spec indicates
			 * that all of the previously transmitted messages must
			 * be sent again, in the same order.  Therefore, we
			 * requeue all the previously transmitted messages, and
			 * start again from the top.  Our simple priority
			 * scheme keeps the messages in the right order.
			 */
			AIC_MISC(("retransmitting  "));
			aic->msgpriq |= aic->msgoutq;
		} else {
			/* This is a continuation of the previous message. */
			n = aic->omp - aic->omess;
			goto nextbyte;
		}
	}

	/* No messages transmitted so far. */
	aic->msgoutq = 0;

nextmsg:
	/* Pick up highest priority message. */
	aic->msgout = aic->msgpriq & -aic->msgpriq;
	aic->msgpriq &= ~aic->msgout;
	aic->msgoutq |= aic->msgout;

	/* Build the outgoing message data. */
	switch (aic->msgout) {
	case SEND_IDENTIFY:
		if (aic->state != AIC_CONNECTED) {
			printf("aic at line %d: SEND_IDENTIFY while not connected; sending NOOP\n", __LINE__);
			AIC_BREAK();
			goto noop;
		}
		acb = aic->nexus;
		aic->omess[0] = MSG_IDENTIFY(acb->xs->sc_link->lun);
		n = 1;
		break;

	case SEND_SDTR:
		if (aic->state != AIC_CONNECTED) {
			printf("aic at line %d: SEND_SDTR while not connected; sending NOOP\n", __LINE__);
			AIC_BREAK();
			goto noop;
		}
		ti = &aic->tinfo[aic->nexus->xs->sc_link->target];
		aic->omess[4] = MSG_EXTENDED;
		aic->omess[3] = 3;
		aic->omess[2] = MSG_EXT_SDTR;
		aic->omess[1] = ti->period >> 2;
		aic->omess[0] = ti->offset;
		n = 5;
		break;

	case SEND_WDTR:
		if (aic->state != AIC_CONNECTED) {
			printf("aic at line %d: SEND_WDTR while not connected; sending NOOP\n", __LINE__);
			AIC_BREAK();
			goto noop;
		}
		ti = &aic->tinfo[aic->nexus->xs->sc_link->target];
		aic->omess[3] = MSG_EXTENDED;
		aic->omess[2] = 2;
		aic->omess[1] = MSG_EXT_WDTR;
		aic->omess[0] = ti->width;
		n = 4;
		break;

	case SEND_DEV_RESET:
		aic->omess[0] = MSG_BUS_DEV_RESET;
		n = 1;
		aic->flags |= AIC_BUSFREE_OK;
		break;

	case SEND_REJECT:
		aic->omess[0] = MSG_MESSAGE_REJECT;
		n = 1;
		break;

	case SEND_PARITY_ERROR:
		aic->omess[0] = MSG_PARITY_ERROR;
		n = 1;
		break;

	case SEND_INIT_DET_ERR:
		aic->omess[0] = MSG_INITIATOR_DET_ERR;
		n = 1;
		break;

	case SEND_ABORT:
		aic->omess[0] = MSG_ABORT;
		n = 1;
		aic->flags |= AIC_BUSFREE_OK;
		break;

	case 0:
		printf("aic at line %d: unexpected MESSAGE OUT; sending NOOP\n", __LINE__);
	noop:
		aic->omess[0] = MSG_NOOP;
		n = 1;
		break;

	default:
		printf("aic at line %d: weird MESSAGE OUT; sending NOOP\n", __LINE__);
		AIC_BREAK();
		goto noop;
	}
	aic->omp = &aic->omess[n];

nextbyte:
	/* Send message bytes. */
	for (; n > 0; n--) {
		do {
			aic->phase = aicphase(aic);
		} while (aic->phase == PH_INVALID);
		if (aic->phase != PH_MSGO) {
			/*
			 * Target left MESSAGE OUT, possibly to reject our
			 * message.
			 */
			goto out;
		}

		/* Clear ATN before last byte if this is the last message. */
		if (n == 1 && aic->msgpriq == 0)
			outb(CLRSINT1, CLRATNO);
		/* Send message byte. */
		outb(SCSIDAT, *--aic->omp);
		/* Wait for ACK to be negated. */
		while ((inb(SCSISIGI) & ACKI) != 0)
			;
	}

	aic->progress = 1;

	/* We get here only if the entire message has been transmitted. */
	if (aic->msgpriq != 0) {
		/* There are more outgoing messages. */
		goto nextmsg;
	}

	/*
	 * The last message has been transmitted.  We need to remember the last
	 * message transmitted (in case the target switches to MESSAGE IN phase
	 * and sends a MESSAGE REJECT), and the list of messages transmitted
	 * this time around (in case the target stays in MESSAGE OUT phase to
	 * request a retransmit).
	 */

out:
	/* Disable REQ/ACK protocol. */
	outb(SXFRCTL0, CHEN);
}

/* aic_dataout_pio: perform a data transfer using the FIFO datapath in the aic6360
 * Precondition: The SCSI bus should be in the DOUT phase, with REQ asserted
 * and ACK deasserted (i.e. waiting for a data byte)
 * This new revision has been optimized (I tried) to make the common case fast,
 * and the rarer cases (as a result) somewhat more comlex
 */
int
aic_dataout_pio(aic, p, n)
	register struct aic_softc *aic;
	u_char *p;
	int n;
{
	register int iobase = aic->iobase;
	register u_char dmastat;
	int out = 0;
#define DOUTAMOUNT 128		/* Full FIFO */

	/* Clear FIFOs and counters. */
	outb(SXFRCTL0, CHEN|CLRSTCNT|CLRCH);
	outb(DMACNTRL0, RSTFIFO|WRITE);
	/* Enable FIFOs. */
	outb(SXFRCTL0, SCSIEN|DMAEN|CHEN);
	outb(DMACNTRL0, ENDMA|DWORDPIO|WRITE);

	/* Setup to detect:
	 * PHASEMIS & PHASECHG: target has left the DOUT phase
	 * SCSIRST: something just pulled the RST line.
	 * BUSFREE: target has unexpectedly left the DOUT phase
	 */
	outb(SIMODE1, ENPHASEMIS|ENSCSIRST|ENBUSFREE|ENPHASECHG);

	/* I have tried to make the main loop as tight as possible.  This
	 * means that some of the code following the loop is a bit more
	 * complex than otherwise.
	 */
	while (n > 0) {
		int xfer;

		for (;;) {
			dmastat = inb(DMASTAT);
			if ((dmastat & DFIFOEMP) != 0)
				break;
			if ((dmastat & INTSTAT) != 0)
				goto phasechange;
		}

		xfer = min(DOUTAMOUNT, n);

		n -= xfer;
		out += xfer;

#if AIC_USE_DWORDS
		if (xfer >= 12) {
			outsl(DMADATALONG, p, xfer>>2);
			p += xfer & ~3;
			xfer &= 3;
		}
#else
		if (xfer >= 8) {
			outsw(DMADATA, p, xfer>>1);
			p += xfer & ~1;
			xfer &= 1;
		}
#endif

		if (xfer > 0) {
			outb(DMACNTRL0, ENDMA|B8MODE|WRITE);
			outsb(DMADATA, p, xfer);
			p += xfer;
			outb(DMACNTRL0, ENDMA|DWORDPIO|WRITE);
		}
	}

	/* See the bytes off chip */
	for (;;) {
		dmastat = inb(DMASTAT);
		if ((dmastat & DFIFOEMP) != 0 &&
		    (inb(SSTAT2) & SEMPTY) != 0)
			break;
		if ((dmastat & INTSTAT) != 0)
			goto phasechange;
	}

phasechange:
	/* We now have the data off chip.  */
	outb(SXFRCTL0, CHEN);

	if ((dmastat & INTSTAT) != 0) {
		/* Some sort of phase change. */
		register u_char sstat2;
		int amount;

		/* Stop transfers, do some accounting */
		amount = inb(FIFOSTAT);
		sstat2 = inb(SSTAT2);
		if ((sstat2 & 7) == 0)
			amount += sstat2 & SFULL ? 8 : 0;
		else
			amount += sstat2 & 7;
		out -= amount;
		AIC_MISC(("+%d ", amount));
	}

	outb(DMACNTRL0, RSTFIFO);
	while ((inb(SXFRCTL0) & SCSIEN) != 0)
		;

	outb(SIMODE1, ENSCSIRST|ENBUSFREE|ENSCSIPERR|ENREQINIT);
	aic->progress = out != 0;

	return out;
}

/* aic_datain_pio: perform data transfers using the FIFO datapath in the aic6360
 * Precondition: The SCSI bus should be in the DIN phase, with REQ asserted
 * and ACK deasserted (i.e. at least one byte is ready).
 * For now, uses a pretty dumb algorithm, hangs around until all data has been
 * transferred.  This, is OK for fast targets, but not so smart for slow
 * targets which don't disconnect or for huge transfers.
 */
int
aic_datain_pio(aic, p, n)
	register struct aic_softc *aic;
	u_char *p;
	int n;
{
	register int iobase = aic->iobase;
	register u_char dmastat;
	int in = 0;
#define DINAMOUNT 128		/* Full FIFO */

	/* Clear FIFOs and counters */
	outb(SXFRCTL0, CHEN|CLRSTCNT|CLRCH);
	outb(DMACNTRL0, RSTFIFO);
	/* Enable FIFOs */
	outb(SXFRCTL0, SCSIEN|DMAEN|CHEN);
	outb(DMACNTRL0, ENDMA|DWORDPIO);

	/* Setup to detect:
	 * PHASEMIS & PHASECHG: target has left the DOUT phase
	 * SCSIRST: something just pulled the RST line.
	 * BUSFREE: target has unexpectedly left the DOUT phase
	 */
	outb(SIMODE1, ENPHASEMIS|ENSCSIRST|ENBUSFREE|ENPHASECHG);

	/* We leave this loop if one or more of the following is true:
	 * a) phase != PH_DIN && FIFOs are empty
	 * b) SCSIRSTI is set (a reset has occurred) or busfree is detected.
	 */
	while (n > 0) {
		int xfer;

		/* Wait for fifo half full or phase mismatch */
		for (;;) {
			dmastat = inb(DMASTAT);
			if ((dmastat & (DFIFOFULL|INTSTAT)) != 0)
				break;
		}

		if ((dmastat & DFIFOFULL) != 0)
			xfer = DINAMOUNT;
		else {
			while ((inb(SSTAT2) & SEMPTY) == 0)
				;
			xfer = inb(FIFOSTAT);
		}

		xfer = min(xfer, n);

		n -= xfer;
		in += xfer;

#if AIC_USE_DWORDS
		if (xfer >= 12) {
			insl(DMADATALONG, p, xfer>>2);
			p += xfer & ~3;
			xfer &= 3;
		}
#else
		if (xfer >= 8) {
			insw(DMADATA, p, xfer>>1);
			p += xfer & ~1;
			xfer &= 1;
		}
#endif

		if (xfer > 0) {
			outb(DMACNTRL0, ENDMA|B8MODE);
			insb(DMADATA, p, xfer);
			p += xfer;
			outb(DMACNTRL0, ENDMA|DWORDPIO);
		}

		if ((dmastat & INTSTAT) != 0)
			break;
	}

#if 0
	if (n > 0)
		printf("residual %d\n", n);
#endif

	/* Some SCSI-devices are rude enough to transfer more data than what
	 * was requested, e.g. 2048 bytes from a CD-ROM instead of the
	 * requested 512.  Test for progress, i.e. real transfers.  If no real
	 * transfers have been performed (n is probably already zero) and the
	 * FIFO is not empty, waste some bytes....
	 */
	if (in == 0) {
		int extra = 0;

		for (;;) {
			dmastat = inb(DMASTAT);
			if ((dmastat & DFIFOEMP) != 0)
				break;
			(void) inb(DMADATA); /* Throw it away */
			extra++;
		}

		AIC_MISC(("aic: %d extra bytes\n", extra));
		aic->progress = extra != 0;
	} else
		aic->progress = 1;

	/* Stop the FIFO data path */
	outb(SXFRCTL0, CHEN);

	outb(DMACNTRL0, RSTFIFO);
	while ((inb(SXFRCTL0) & SCSIEN) != 0)
		;

	outb(SIMODE1, ENSCSIRST|ENBUSFREE|ENSCSIPERR|ENREQINIT);

	return in;
}

/*
 * This is the workhorse routine of the driver.
 * Deficiencies (for now):
 * 1) always uses programmed I/O
 * 2) doesn't support synchronous transfers properly (yet)
 */
int
aicintr(aic)
	register struct aic_softc *aic;
{
	register int iobase = aic->iobase;
	u_char sstat0, sstat1;
	register struct acb *acb;
	register struct scsi_link *sc;
	struct aic_tinfo *ti;
	int n;

	/*
	 * Clear INTEN.  We enable it again before returning.  This ensures
	 * that we get another edge on the next `interesting' event.
	 */
	outb(DMACNTRL0, 0);
	AIC_TRACE(("aicintr  "));

	/*
	 * First check for abnormal conditions, such as reset.
	 */
	sstat1 = inb(SSTAT1);
	AIC_MISC(("sstat1:0x%02x ", sstat1));
	if ((sstat1 & SCSIRSTI) != 0) {
		printf("aic: reset in -- reinitializing....\n");
		goto reset;
	}
	if ((sstat1 & SCSIPERR) != 0) {
		printf("aic: SCSI bus parity error\n");
		outb(CLRSINT1, CLRSCSIPERR);
		if (aic->prevphase == PH_MSGI) {
			aic_sched_msgout(SEND_PARITY_ERROR);
			aic->flags |= AIC_DROP_MSGI;
		} else
			aic_sched_msgout(SEND_INIT_DET_ERR);
	}

	/*
	 * If we're not already busy doing something test for the following
	 * conditions:
	 * 1) We have been reselected by something
	 * 2) We have selected something successfully
	 * 3) Our selection process has timed out
	 * 4) This is really a bus free interrupt just to get a new command
	 *    going?
	 * 5) Spurious interrupt?
	 */
	sstat0 = inb(SSTAT0);
	AIC_MISC(("sstat0:0x%02x ", sstat0));

	switch (aic->state) {
	case AIC_IDLE:
	case AIC_SELECTING:
		if ((sstat0 & SELDI) != 0) {
			AIC_MISC(("reselected  "));

			/*
			 * If we're trying to select a target ourselves,
			 * push our command back into the ready list.
			 */
			if (aic->state == AIC_SELECTING) {
				AIC_MISC(("backoff selector  "));
				TAILQ_INSERT_HEAD(&aic->ready_list, aic->nexus,
				    chain);
				aic->nexus = NULL;
			}

			/*
			 * Turn off selection stuff, and prepare to catch bus
			 * free interrupts and parity errors.
			 */
			outb(SXFRCTL1, 0);
			outb(SCSISEQ, ENAUTOATNP);
			outb(CLRSINT0, CLRSELDI);
			outb(CLRSINT1, CLRBUSFREE|CLRSCSIPERR);
			outb(SIMODE0, 0);
			outb(SIMODE1, ENSCSIRST|ENSCSIPERR|ENBUSFREE|ENREQINIT);

			aic->state = AIC_RESELECTED;
			goto reselected;
		} else if ((sstat0 & SELDO) != 0) {
			AIC_MISC(("selected  "));

			/* We have selected a target. Things to do:
			 * a) Determine what message(s) to send.
			 * b) Verify that we're still selecting the target.
			 * c) Mark device as busy.
			 */
			if (aic->state != AIC_SELECTING) {
				printf("aic at line %d: selection out while not selecting; resetting\n", __LINE__);
				AIC_BREAK();
				goto reset;
			}
			acb = aic->nexus;

			sc = acb->xs->sc_link;
			ti = &aic->tinfo[sc->target];
			if ((acb->xs->flags & SCSI_RESET) == 0) {
				aic->msgpriq = SEND_IDENTIFY;
				if ((ti->flags & DO_SYNC) != 0)
					aic->msgpriq |= SEND_SDTR;
				if ((ti->flags & DO_WIDE) != 0)
					aic->msgpriq |= SEND_WDTR;
			} else
				aic->msgpriq = SEND_DEV_RESET;

			/*
			 * Turn off selection stuff, and prepare to catch bus
			 * free interrupts and parity errors.
			 */
			outb(SXFRCTL1, 0);
			outb(SCSISEQ, ENAUTOATNP);
			outb(CLRSINT0, CLRSELDO);
			outb(CLRSINT1, CLRBUSFREE|CLRSCSIPERR);
			outb(SIMODE0, 0);
			outb(SIMODE1, ENSCSIRST|ENSCSIPERR|ENBUSFREE|ENREQINIT);

			aic->flags = 0;
			aic->prevphase = PH_INVALID;
			ti->lubusy |= (1<<sc->lun);

			/* Do an implicit RESTORE POINTERS. */
			aic->dp = acb->dp;
			aic->dleft = acb->dleft;
			aic->cp = (u_char *)&acb->cmd;
			aic->cleft = acb->clen;

			aic->state = AIC_CONNECTED;
			goto connected;
		} else if ((sstat1 & SELTO) != 0) {
			AIC_MISC(("selection timeout  "));

			if (aic->state != AIC_SELECTING) {
				printf("aic at line %d: selection timeout while not selecting; resetting\n", __LINE__);
				AIC_BREAK();
				goto reset;
			}
			acb = aic->nexus;

			outb(SXFRCTL1, 0);
			outb(CLRSINT1, CLRSELTIMO);

			acb->xs->error = XS_TIMEOUT;
			untimeout(aic_timeout, acb);
			delay(250);
			aic_done(acb);
		} else {
			if (aic->state != AIC_IDLE) {
				printf("aic at line %d: BUS FREE while not idle; state=%d\n", __LINE__, aic->state);
				AIC_BREAK();
			}

			aic_sched(aic);
		}
		break;

	case AIC_RESELECTED:
	reselected:
		/* Now, we're expecting an IDENTIFY message. */
		aic->phase = aicphase(aic);
		AIC_MISC(("phase=0x%02x  ", aic->phase));
		if ((aic->phase & PH_PSBIT) == 0)
			outb(SCSISIGO, aic->phase);
		outb(CLRSINT1, CLRPHASECHG|CLRBUSFREE);

		switch (aic->phase) {
		case PH_INVALID:
			break;

		case PH_BUSFREE:
			aic->state = AIC_IDLE;
			aic_sched(aic);
			break;

		case PH_MSGI:
			aic_msgin(aic);
			aic->prevphase = PH_MSGI;
			if (aic->state == AIC_CONNECTED)
				goto connected;
			break;

		default:
			printf("aic at line %d: reselect without MESSAGE IN; resetting\n", __LINE__);
			AIC_BREAK();
			goto reset;
		}
		break;

	case AIC_CONNECTED:
	connected:
		acb = aic->nexus;

		/* What sort of transfer does the bus signal? */
		aic->phase = aicphase(aic);
		AIC_MISC(("phase=0x%02x  ", aic->phase));
		if ((aic->phase & PH_PSBIT) == 0)
			outb(SCSISIGO, aic->phase);
		outb(CLRSINT1, CLRPHASECHG|CLRBUSFREE);

		switch (aic->phase) {
		case PH_INVALID:
			break;

		case PH_BUSFREE:
			if ((aic->flags & AIC_BUSFREE_OK) == 0) {
				printf("aic at line %d: unexpected BUS FREE while connected; aborting\n", __LINE__);
				AIC_BREAK();

				acb->xs->error = XS_DRIVER_STUFFUP;
				untimeout(aic_timeout, acb);
				aic_done(acb);
				goto out;
			}
			aic->flags &= ~AIC_BUSFREE_OK;
			break;

		case PH_MSGO:
			aic_msgout(aic);
			aic->prevphase = PH_MSGO;
			break;

		case PH_MSGI:
			aic_msgin(aic);
			aic->prevphase = PH_MSGI;
			break;

		case PH_CMD:		/* CMD phase & REQ asserted */
			AIC_MISC(("cmd=0x%02x+%d  ", acb->cmd.opcode, acb->clen-1));
			n = aic_dataout_pio(aic, aic->cp, aic->cleft);
			aic->cp += n;
			aic->cleft -= n;
			aic->prevphase = PH_CMD;
			break;

		case PH_DOUT:
			AIC_MISC(("dleft=%d  ", aic->dleft));
			n = aic_dataout_pio(aic, aic->dp, aic->dleft);
			aic->dp += n;
			aic->dleft -= n;
			aic->prevphase = PH_DOUT;
			break;

		case PH_DIN:
			n = aic_datain_pio(aic, aic->dp, aic->dleft);
			aic->dp += n;
			aic->dleft -= n;
			aic->prevphase = PH_DIN;
			break;

		case PH_STAT:
			outb(SXFRCTL0, CHEN|SPIOEN);
			outb(DMACNTRL0, RSTFIFO);
			outb(SIMODE1, ENSCSIRST|ENPHASEMIS|ENBUSFREE|ENSCSIPERR);
			acb->stat = inb(SCSIDAT);
			outb(SXFRCTL0, CHEN);
			AIC_MISC(("stat=0x%02x  ", acb->stat));
			outb(SIMODE1, ENSCSIRST|ENBUSFREE|ENSCSIPERR|ENREQINIT);
			aic->prevphase = PH_STAT;
			break;

		default:
			printf("aic at line %d: bogus phase while connected; resetting\n", __LINE__);
			AIC_BREAK();
			goto reset;
		}
		break;
	}

out:
	outb(DMACNTRL0, INTEN);
	return 1;

reset:
	aic_init(aic);
	return 1;
}

void
aic_timeout(arg)
	void *arg;
{
	struct acb *acb = (struct acb *)arg;
	int s;

	s = splbio();

	sc_print_addr(acb->xs->sc_link);
	printf("timed out\n");

	acb->xs->error = XS_TIMEOUT;
	aic_done(acb);

	splx(s);
}

#ifdef AIC_DEBUG
/*
 * The following functions are mostly used for debugging purposes, either
 * directly called from the driver or from the kernel debugger.
 */

void
aic_show_scsi_cmd(acb)
	struct acb *acb;
{
	u_char  *b = (u_char *)&acb->cmd;
	struct scsi_link *sc = acb->xs->sc_link;
	int i;

	sc_print_addr(sc);
	if ((acb->xs->flags & SCSI_RESET) == 0) {
		for (i = 0; i < acb->clen; i++) {
			if (i)
				printf(",");
			printf("%x", b[i]);
		}
		printf("\n");
	} else
		printf("RESET\n");
}

void
aic_print_acb(acb)
	struct acb *acb;
{

	printf("acb@%x xs=%x flags=%x", acb, acb->xs, acb->flags);
	printf(" dp=%x dleft=%d stat=%x\n",
	    (long)acb->dp, acb->dleft, acb->stat);
	aic_show_scsi_cmd(acb);
}

void
aic_print_active_acb()
{
	struct acb *acb;
	struct aic_softc *aic = aiccd.cd_devs[0];

	printf("ready list:\n");
	for (acb = aic->ready_list.tqh_first; acb; acb = acb->chain.tqe_next)
		aic_print_acb(acb);
	printf("nexus:\n");
	if (aic->nexus)
		aic_print_acb(aic->nexus);
	printf("nexus list:\n");
	for (acb = aic->nexus_list.tqh_first; acb; acb = acb->chain.tqe_next)
		aic_print_acb(acb);
}

void
aic_dump6360(aic)
	struct aic_softc *aic;
{
	int iobase = aic->iobase;

	printf("aic6360: SCSISEQ=%x SXFRCTL0=%x SXFRCTL1=%x SCSISIGI=%x\n",
	    inb(SCSISEQ), inb(SXFRCTL0), inb(SXFRCTL1), inb(SCSISIGI));
	printf("         SSTAT0=%x SSTAT1=%x SSTAT2=%x SSTAT3=%x SSTAT4=%x\n",
	    inb(SSTAT0), inb(SSTAT1), inb(SSTAT2), inb(SSTAT3), inb(SSTAT4));
	printf("         SIMODE0=%x SIMODE1=%x DMACNTRL0=%x DMACNTRL1=%x DMASTAT=%x\n",
	    inb(SIMODE0), inb(SIMODE1), inb(DMACNTRL0), inb(DMACNTRL1),
	    inb(DMASTAT));
	printf("         FIFOSTAT=%d SCSIBUS=0x%x\n",
	    inb(FIFOSTAT), inb(SCSIBUS));
}

void
aic_dump_driver(aic)
	struct aic_softc *aic;
{
	struct aic_tinfo *ti;
	int i;

	printf("nexus=%x phase=%x prevphase=%x\n", aic->nexus, aic->phase,
	    aic->prevphase);
	printf("state=%x msgin=%x msgpriq=%x msgoutq=%x msgout=%x\n",
	    aic->state, aic->imess[0], aic->msgpriq, aic->msgoutq, aic->msgout);
	for (i = 0; i < 7; i++) {
		ti = &aic->tinfo[i];
		printf("tinfo%d: %d cmds %d disconnects %d timeouts",
		    i, ti->cmds, ti->dconns, ti->touts);
		printf(" %d senses flags=%x\n", ti->senses, ti->flags);
	}
}
#endif