sii.c

早期freebsd实现

/*-
 * 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.
 *
 *	@(#)sii.c	8.2 (Berkeley) 11/30/93
 *
 * from: $Header: /sprite/src/kernel/dev/ds3100.md/RCS/devSII.c,
 *	v 9.2 89/09/14 13:37:41 jhh Exp $ SPRITE (DECWRL)";
 */

#include "sii.h"
#if NSII > 0
/*
 * SCSI interface driver
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dkstat.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/errno.h>

#include <machine/machConst.h>
#include <pmax/dev/device.h>
#include <pmax/dev/scsi.h>
#include <pmax/dev/siireg.h>

#include <pmax/pmax/kn01.h>

int	siiprobe();
void	siistart();
struct	driver siidriver = {
	"sii", siiprobe, siistart, 0,
};

typedef struct scsi_state {
	int	statusByte;	/* status byte returned during STATUS_PHASE */
	int	dmaDataPhase;	/* which data phase to expect */
	int	dmaCurPhase;	/* SCSI phase if DMA is in progress */
	int	dmaPrevPhase;	/* SCSI phase of DMA suspended by disconnect */
	u_short	*dmaAddr[2];	/* DMA buffer memory address */
	int	dmaBufIndex;	/* which of the above is currently in use */
	int	dmalen;		/* amount to transfer in this chunk */
	int	cmdlen;		/* total remaining amount of cmd to transfer */
	u_char	*cmd;		/* current pointer within scsicmd->cmd */
	int	buflen;		/* total remaining amount of data to transfer */
	char	*buf;		/* current pointer within scsicmd->buf */
	u_short	flags;		/* see below */
	u_short	prevComm;	/* command reg before disconnect */
	u_short	dmaCtrl;	/* DMA control register if disconnect */
	u_short	dmaAddrL;	/* DMA address register if disconnect */
	u_short	dmaAddrH;	/* DMA address register if disconnect */
	u_short	dmaCnt;		/* DMA count if disconnect */
	u_short	dmaByte;	/* DMA byte if disconnect on odd boundary */
	u_short	dmaReqAck;	/* DMA synchronous xfer offset or 0 if async */
} State;

/* state flags */
#define FIRST_DMA	0x01	/* true if no data DMA started yet */

#define SII_NCMD	7
struct siisoftc {
	SIIRegs	*sc_regs;		/* HW address of SII controller chip */
	int	sc_flags;
	int	sc_target;		/* target SCSI ID if connected */
	ScsiCmd	*sc_cmd[SII_NCMD];	/* active command indexed by ID */
	State	sc_st[SII_NCMD];	/* state info for each active command */
} sii_softc[NSII];

/* 
 * MACROS for timing out spin loops.
 *
 * Wait until expression is true.
 *
 * Control register bits can change at any time so when the CPU
 * reads a register, the bits might change and
 * invalidate the setup and hold times for the CPU.
 * This macro reads the register twice to be sure the value is stable.
 *
 *	args:	var 		- variable to save control register contents
 *		reg		- control register to read
 *		expr 		- expression to spin on
 *		spincount 	- maximum number of times through the loop
 *		cntr		- variable for number of tries
 */
#define	SII_WAIT_UNTIL(var, reg, expr, spincount, cntr) {	\
		register unsigned tmp = reg;			\
		for (cntr = 0; cntr < spincount; cntr++) {	\
			while (tmp != (var = reg))		\
				tmp = var;			\
			if (expr)				\
				break;				\
			if (cntr >= 100)			\
				DELAY(100);			\
		}						\
	}

#ifdef DEBUG
int	sii_debug = 1;
int	sii_debug_cmd;
int	sii_debug_bn;
int	sii_debug_sz;
#define NLOG 16
struct sii_log {
	u_short	cstat;
	u_short	dstat;
	u_short	comm;
	u_short	msg;
	int	target;
} sii_log[NLOG], *sii_logp = sii_log;
#endif

u_char	sii_buf[256];	/* used for extended messages */

#define NORESET	0
#define RESET	1
#define NOWAIT	0
#define WAIT	1

/* define a safe address in the SCSI buffer for doing status & message DMA */
#define SII_BUF_ADDR	(MACH_PHYS_TO_UNCACHED(KN01_SYS_SII_B_START) \
		+ SII_MAX_DMA_XFER_LENGTH * 14)

static void sii_Reset();
static void sii_StartCmd();
static void sii_CmdDone();
static void sii_DoIntr();
static void sii_StateChg();
static void sii_DoSync();
static void sii_StartDMA();
static int sii_GetByte();

/*
 * Test to see if device is present.
 * Return true if found and initialized ok.
 */
siiprobe(cp)
	register struct pmax_ctlr *cp;
{
	register struct siisoftc *sc;
	register int i;

	if (cp->pmax_unit >= NSII)
		return (0);
	sc = &sii_softc[cp->pmax_unit];
	sc->sc_regs = (SIIRegs *)cp->pmax_addr;
	sc->sc_flags = cp->pmax_flags;
	sc->sc_target = -1;	/* no command active */
	/*
	 * Give each target its own DMA buffer region.
	 * Make it big enough for 2 max transfers so we can ping pong buffers
	 * while we copy the data.
	 */
	for (i = 0; i < SII_NCMD; i++) {
		sc->sc_st[i].dmaAddr[0] = (u_short *)
			MACH_PHYS_TO_UNCACHED(KN01_SYS_SII_B_START) +
			2 * SII_MAX_DMA_XFER_LENGTH * i;
		sc->sc_st[i].dmaAddr[1] = sc->sc_st[i].dmaAddr[0] +
			SII_MAX_DMA_XFER_LENGTH;
	}

	printf("sii%d at nexus0 csr 0x%x\n", cp->pmax_unit, cp->pmax_addr);
	sii_Reset(sc->sc_regs, RESET);
	return (1);
}

/*
 * Start activity on a SCSI device.
 * We maintain information on each device separately since devices can
 * connect/disconnect during an operation.
 */
void
siistart(scsicmd)
	register ScsiCmd *scsicmd;	/* command to start */
{
	register struct scsi_device *sdp = scsicmd->sd;
	register struct siisoftc *sc = &sii_softc[sdp->sd_ctlr];
	int s;

	s = splbio();
	/*
	 * Check if another command is already in progress.
	 * We may have to change this if we allow SCSI devices with
	 * separate LUNs.
	 */
	if (sc->sc_cmd[sdp->sd_drive]) {
		printf("sii%d: device %s busy at start\n", sdp->sd_ctlr,
			sdp->sd_driver->d_name);
		(*sdp->sd_driver->d_done)(scsicmd->unit, EBUSY,
			scsicmd->buflen, 0);
		splx(s);
	}
	sc->sc_cmd[sdp->sd_drive] = scsicmd;
	sii_StartCmd(sc, sdp->sd_drive);
	splx(s);
}

/*
 * Check to see if any SII chips have pending interrupts
 * and process as appropriate.
 */
void
siiintr(unit)
	int unit;
{
	register struct siisoftc *sc = &sii_softc[unit];
	unsigned dstat;

	/*
	 * Find which controller caused the interrupt.
	 */
	dstat = sc->sc_regs->dstat;
	if (dstat & (SII_CI | SII_DI))
		sii_DoIntr(sc, dstat);
}

/*
 * Reset the SII chip and do a SCSI reset if 'reset' is true.
 * NOTE: if !cold && reset, should probably probe for devices
 * since a SCSI bus reset will set UNIT_ATTENTION.
 */
static void
sii_Reset(regs, reset)
	register SIIRegs *regs;
	int reset;				/* TRUE => reset SCSI bus */
{

#ifdef DEBUG
	if (sii_debug > 1)
		printf("sii: RESET\n");
#endif
	/*
	 * Reset the SII chip.
	 */
	regs->comm = SII_CHRESET;
	/*
	 * Set arbitrated bus mode.
	 */
	regs->csr = SII_HPM;
	/*
	 * SII is always ID 7.
	 */
	regs->id = SII_ID_IO | 7;
	/*
	 * Enable SII to drive the SCSI bus.
	 */
	regs->dictrl = SII_PRE;
	regs->dmctrl = 0;

	if (reset) {
		register int i;

		/*
		 * Assert SCSI bus reset for at least 25 Usec to clear the 
		 * world. SII_DO_RST is self clearing.
		 * Delay 250 ms before doing any commands.
		 */
		regs->comm = SII_DO_RST;
		MachEmptyWriteBuffer();
		DELAY(250000);

		/* rearbitrate synchronous offset */
		for (i = 0; i < SII_NCMD; i++)
			sii_softc[0].sc_st[i].dmaReqAck = 0;
	}

	/*
	 * Clear any pending interrupts from the reset.
	 */
	regs->cstat = regs->cstat;
	regs->dstat = regs->dstat;
	/*
	 * Set up SII for arbitrated bus mode, SCSI parity checking,
	 * Reselect Enable, and Interrupt Enable.
	 */
	regs->csr = SII_HPM | SII_RSE | SII_PCE | SII_IE;
	MachEmptyWriteBuffer();
}

/*
 * Start a SCSI command by sending the cmd data
 * to a SCSI controller via the SII.
 * Call the device done proceedure if it can't be started.
 * NOTE: we should be called with interrupts disabled.
 */
static void
sii_StartCmd(sc, target)
	register struct siisoftc *sc;	/* which SII to use */
	register int target;		/* which command to start */
{
	register SIIRegs *regs;	
	register ScsiCmd *scsicmd;
	register State *state;
	register unsigned status;
	int error, retval;

	/* if another command is currently in progress, just wait */
	if (sc->sc_target >= 0)
		return;

	/* initialize state information for this command */
	scsicmd = sc->sc_cmd[target];
	state = &sc->sc_st[target];
	state->flags = FIRST_DMA;
	state->prevComm = 0;
	state->dmalen = 0;
	state->dmaCurPhase = -1;
	state->dmaPrevPhase = -1;
	state->dmaBufIndex = 0;
	state->cmd = scsicmd->cmd;
	state->cmdlen = scsicmd->cmdlen;
	if ((state->buflen = scsicmd->buflen) == 0) {
		state->dmaDataPhase = -1; /* illegal phase. shouldn't happen */
		state->buf = (char *)0;
	} else {
		state->dmaDataPhase =
			(scsicmd->flags & SCSICMD_DATA_TO_DEVICE) ?
			SII_DATA_OUT_PHASE : SII_DATA_IN_PHASE;
		state->buf = scsicmd->buf;
	}

#ifdef DEBUG
	if (sii_debug > 1) {
		printf("sii_StartCmd: %s target %d cmd 0x%x addr %x size %d dma %d\n",
			scsicmd->sd->sd_driver->d_name, target,
			scsicmd->cmd[0], scsicmd->buf, scsicmd->buflen,
			state->dmaDataPhase);
	}
	sii_debug_cmd = scsicmd->cmd[0];
	if (scsicmd->cmd[0] == SCSI_READ_EXT) {
		sii_debug_bn = (scsicmd->cmd[2] << 24) |
			(scsicmd->cmd[3] << 16) |
			(scsicmd->cmd[4] << 8) |
			scsicmd->cmd[5];
		sii_debug_sz = (scsicmd->cmd[7] << 8) | scsicmd->cmd[8];
	}
#endif

	/* try to select the target */
	regs = sc->sc_regs;

	/*
	 * Another device may have selected us; in which case,
	 * this command will be restarted later.
	 */
	if ((status = regs->dstat) & (SII_CI | SII_DI)) {
		sii_DoIntr(sc, status);
		return;
	}

	sc->sc_target = target;
	if (scsicmd->flags & SCSICMD_USE_SYNC) {
		printf("sii_StartCmd: doing extended msg\n"); /* XXX */
		/*
		 * Setup to send both the identify message and the synchronous
		 * data transfer request.
		 */
		sii_buf[0] = SCSI_DIS_REC_IDENTIFY;
		sii_buf[1] = SCSI_EXTENDED_MSG;
		sii_buf[2] = 3;		/* message length */
		sii_buf[3] = SCSI_SYNCHRONOUS_XFER;
		sii_buf[4] = 0;
		sii_buf[5] = 3;		/* maximum SII chip supports */

		state->dmaCurPhase = SII_MSG_OUT_PHASE,
		state->dmalen = 6;
		CopyToBuffer((u_short *)sii_buf,
			(volatile u_short *)SII_BUF_ADDR, 6);
		regs->slcsr = target;
		regs->dmctrl = 0;
		regs->dmaddrl = ((u_short)SII_BUF_ADDR >> 1);
		regs->dmaddrh = ((u_short)SII_BUF_ADDR >> 17) & 03;
		regs->dmlotc = 6;
		regs->comm = SII_DMA | SII_INXFER | SII_SELECT | SII_ATN |
			SII_CON | SII_MSG_OUT_PHASE;
	} else {
		/* do a chained, select with ATN and programmed I/O command */
		regs->data = SCSI_DIS_REC_IDENTIFY;
		regs->slcsr = target;
		regs->dmctrl = 0;
		regs->comm = SII_INXFER | SII_SELECT | SII_ATN | SII_CON |
			SII_MSG_OUT_PHASE;
	}
	MachEmptyWriteBuffer();

	/*
	 * Wait for something to happen
	 * (should happen soon or we would use interrupts).
	 */
	SII_WAIT_UNTIL(status, regs->cstat, status & (SII_CI | SII_DI),
		SII_WAIT_COUNT/4, retval);

	/* check to see if we are connected OK */
	if ((status & (SII_RST | SII_SCH | SII_STATE_MSK)) ==
	    (SII_SCH | SII_CON)) {
		regs->cstat = status;
		MachEmptyWriteBuffer();

#ifdef DEBUG
		sii_logp->target = target;
		sii_logp->cstat = status;
		sii_logp->dstat = 0;
		sii_logp->comm = regs->comm;
		sii_logp->msg = -1;
		if (++sii_logp >= &sii_log[NLOG])
			sii_logp = sii_log;
#endif

		/* wait a short time for command phase */
		SII_WAIT_UNTIL(status, regs->dstat, status & SII_MIS,
			SII_WAIT_COUNT, retval);
#ifdef DEBUG
		if (sii_debug > 2)
			printf("sii_StartCmd: ds %x cnt %d\n", status, retval);
#endif
		if ((status & (SII_CI | SII_MIS | SII_PHASE_MSK)) !=
		    (SII_MIS | SII_CMD_PHASE)) {
			printf("sii_StartCmd: timeout cs %x ds %x cnt %d\n",
				regs->cstat, status, retval); /* XXX */
			/* process interrupt or continue until it happens */
			if (status & (SII_CI | SII_DI))
				sii_DoIntr(sc, status);
			return;
		}
		regs->dstat = SII_DNE;	/* clear Msg Out DMA done */

		/* send command data */
		CopyToBuffer((u_short *)state->cmd,
			(volatile u_short *)state->dmaAddr[0], state->cmdlen);
		sii_StartDMA(regs, state->dmaCurPhase = SII_CMD_PHASE,
			state->dmaAddr[0], state->dmalen = scsicmd->cmdlen);

		/* wait a little while for DMA to finish */
		SII_WAIT_UNTIL(status, regs->dstat, status & (SII_CI | SII_DI),
			SII_WAIT_COUNT, retval);
#ifdef DEBUG
		if (sii_debug > 2)
			printf("sii_StartCmd: ds %x, cnt %d\n", status, retval);
#endif
		if (status & (SII_CI | SII_DI))
			sii_DoIntr(sc, status);
#ifdef DEBUG
		if (sii_debug > 2)
			printf("sii_StartCmd: DONE ds %x\n", regs->dstat);
#endif
		return;
	}

	/*
	 * Another device may have selected us; in which case,
	 * this command will be restarted later.
	 */
	if (status & (SII_CI | SII_DI)) {
		sii_DoIntr(sc, regs->dstat);
		return;
	}

	/*
	 * Disconnect if selection command still in progress.
	 */
	if (status & SII_SIP) {
		error = ENXIO;	/* device didn't respond */
		regs->comm = SII_DISCON;
		MachEmptyWriteBuffer();
		SII_WAIT_UNTIL(status, regs->cstat,
			!(status & (SII_CON | SII_SIP)),
			SII_WAIT_COUNT, retval);
	} else
		error = EBUSY;	/* couldn't get the bus */
#ifdef DEBUG
	if (sii_debug > 1)
		printf("sii_StartCmd: Couldn't select target %d error %d\n",
			target, error);
#endif
	sc->sc_target = -1;
	regs->cstat = 0xffff;
	regs->dstat = 0xffff;
	regs->comm = 0;
	MachEmptyWriteBuffer();
	sii_CmdDone(sc, target, error);
}

/*
 * Process interrupt conditions.
 */
static void
sii_DoIntr(sc, dstat)
	register struct siisoftc *sc;
	register unsigned dstat;
{
	register SIIRegs *regs = sc->sc_regs;
	register State *state;
	register unsigned cstat;
	register int i;
	unsigned comm, msg;

again:
	comm = regs->comm;

#ifdef DEBUG
	if (sii_debug > 3)
		printf("sii_DoIntr: cs %x, ds %x cm %x ",
			regs->cstat, dstat, comm);
	sii_logp->target = sc->sc_target;
	sii_logp->cstat = regs->cstat;
	sii_logp->dstat = dstat;
	sii_logp->comm = comm;
	sii_logp->msg = -1;
	if (++sii_logp >= &sii_log[NLOG])
		sii_logp = sii_log;
#endif

	regs->dstat = dstat;	/* acknowledge everything */
	MachEmptyWriteBuffer();

	if (dstat & SII_CI) {
		/* deglitch cstat register */
		msg = regs->cstat;
		while (msg != (cstat = regs->cstat))
			msg = cstat;
		regs->cstat = cstat;	/* acknowledge everything */