/*	$NetBSD: ct.c,v 1.61.32.1 2021/07/14 18:04:04 martin Exp $	*/

/*-
 * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1982, 1990, 1993
 *	The Regents of the University of California.  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. 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.
 *
 *	@(#)ct.c	8.2 (Berkeley) 1/12/94
 */

/*
 * CS80 cartridge tape driver (9144, 88140, 9145)
 *
 * Reminder:
 *	C_CC bit (character count option) when used in the CS/80 command
 *	'set options' will cause the tape not to stream.
 *
 * TODO:
 *	make filesystem compatible
 *	make block mode work according to mtio(4) spec. (if possible)
 *	merge with cs80 disk driver
 *	finish support of 9145
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ct.c,v 1.61.32.1 2021/07/14 18:04:04 martin Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/ioctl.h>
#include <sys/mtio.h>
#include <sys/proc.h>
#include <sys/tprintf.h>

#include <hp300/dev/hpibvar.h>

#include <hp300/dev/ctreg.h>

#include "ioconf.h"

/* number of eof marks to remember */
#define EOFS	128

struct	ct_softc {
	device_t sc_dev;
	int	sc_slave;		/* HP-IB slave ID */
	int	sc_punit;		/* physical unit */
	struct	ct_iocmd sc_ioc;
	struct	ct_rscmd sc_rsc;
	struct	ct_stat sc_stat;
	struct	ct_ssmcmd sc_ssmc;
	struct	ct_srcmd sc_src;
	struct	ct_soptcmd sc_soptc;
	struct	ct_ulcmd sc_ul;
	struct	ct_wfmcmd sc_wfm;
	struct	ct_clearcmd sc_clear;
	struct	bufq_state *sc_tab;
	int	sc_active;
	struct	buf *sc_bp;
	struct	buf sc_bufstore;	/* XXX */
	int	sc_blkno;
	int	sc_cmd;
	int	sc_resid;
	char	*sc_addr;
	int	sc_flags;
	short	sc_type;
	tpr_t	sc_tpr;
	struct	hpibqueue sc_hq;	/* entry on hpib job queue */
	int	sc_eofp;
	int	sc_eofs[EOFS];
};

/* flags */
#define	CTF_OPEN	0x01
#define	CTF_ALIVE	0x02
#define	CTF_WRT		0x04
#define	CTF_CMD		0x08
#define	CTF_IO		0x10
#define	CTF_BEOF	0x20
#define	CTF_AEOF	0x40
#define	CTF_EOT		0x80
#define	CTF_STATWAIT	0x100
#define CTF_CANSTREAM	0x200
#define	CTF_WRTTN	0x400

static int	ctmatch(device_t, cfdata_t, void *);
static void	ctattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(ct, sizeof(struct ct_softc),
    ctmatch, ctattach, NULL, NULL);

static dev_type_open(ctopen);
static dev_type_close(ctclose);
static dev_type_read(ctread);
static dev_type_write(ctwrite);
static dev_type_ioctl(ctioctl);
static dev_type_strategy(ctstrategy);

const struct bdevsw ct_bdevsw = {
	.d_open = ctopen,
	.d_close = ctclose,
	.d_strategy = ctstrategy,
	.d_ioctl = ctioctl,
	.d_dump = nodump,
	.d_psize = nosize,
	.d_discard = nodiscard,
	.d_flag = D_TAPE
};

const struct cdevsw ct_cdevsw = {
	.d_open = ctopen,
	.d_close = ctclose,
	.d_read = ctread,
	.d_write = ctwrite,
	.d_ioctl = ctioctl,
	.d_stop = nostop,
	.d_tty = notty,
	.d_poll = nopoll,
	.d_mmap = nommap,
	.d_kqfilter = nokqfilter,
	.d_discard = nodiscard,
	.d_flag = D_TAPE
};

static int	ctident(device_t, struct ct_softc *,
		    struct hpibbus_attach_args *);

static void	ctreset(struct ct_softc *);
static void	ctaddeof(struct ct_softc *);
static void	ctustart(struct ct_softc *);
static void	cteof(struct ct_softc *, struct buf *);
static void	ctdone(struct ct_softc *, struct buf *);

static void	ctstart(void *);
static void	ctgo(void *);
static void	ctintr(void *);

static void	ctcommand(dev_t, int, int);

static const struct ctinfo {
	short	hwid;
	short	punit;
	const char *desc;
} ctinfo[] = {
	{ CT7946ID,	1,	"7946A"	},
	{ CT7912PID,	1,	"7912P"	},
	{ CT7914PID,	1,	"7914P"	},
	{ CT9144ID,	0,	"9144"	},
	{ CT9145ID,	0,	"9145"	},
	{ CT35401ID,	0,	"35401A"},
};
static const int nctinfo = __arraycount(ctinfo);

#define	CT_NOREW	4
#define	CT_STREAM	8
#define	UNIT(x)		(minor(x) & 3)
#define	ctpunit(x)	((x) & 7)

#ifdef DEBUG
int ctdebug = 0;
#define CDB_FILES	0x01
#define CT_BSF		0x02
#endif

static int
ctmatch(device_t parent, cfdata_t cf, void *aux)
{
	struct hpibbus_attach_args *ha = aux;

	return ctident(parent, NULL, ha);
}

static void
ctattach(device_t parent, device_t self, void *aux)
{
	struct ct_softc *sc = device_private(self);
	struct hpibbus_attach_args *ha = aux;

	sc->sc_dev = self;
	if (ctident(parent, sc, ha) == 0) {
		aprint_error(": didn't respond to describe command!\n");
		return;
	}

	sc->sc_slave = ha->ha_slave;
	sc->sc_punit = ha->ha_punit;

	bufq_alloc(&sc->sc_tab, "fcfs", 0);

	/* Initialize hpib job queue entry. */
	sc->sc_hq.hq_softc = sc;
	sc->sc_hq.hq_slave = sc->sc_slave;
	sc->sc_hq.hq_start = ctstart;
	sc->sc_hq.hq_go = ctgo;
	sc->sc_hq.hq_intr = ctintr;

	ctreset(sc);
	sc->sc_flags |= CTF_ALIVE;
}

static int
ctident(device_t parent, struct ct_softc *sc, struct hpibbus_attach_args *ha)
{
	struct cs80_describe desc;
	u_char stat, cmd[3];
	char name[7];
	int i, id, n, type, canstream;

	type = canstream = 0;

	/* Verify that we have a CS80 device. */
	if ((ha->ha_id & 0x200) == 0)
		return 0;

	/* Is it one of the tapes we support? */
	for (id = 0; id < nctinfo; id++)
		if (ha->ha_id == ctinfo[id].hwid &&
		    ha->ha_punit == ctinfo[id].punit)
			break;
	if (id == nctinfo)
		return 0;

	/*
	 * So far, so good.  Get drive parameters.  Note command
	 * is always issued to unit 0.
	 */
	cmd[0] = C_SUNIT(0);
	cmd[1] = C_SVOL(0);
	cmd[2] = C_DESC;
	hpibsend(device_unit(parent), ha->ha_slave, C_CMD, cmd, sizeof(cmd));
	hpibrecv(device_unit(parent), ha->ha_slave, C_EXEC, &desc,
	    sizeof(desc));
	hpibrecv(device_unit(parent), ha->ha_slave, C_QSTAT, &stat,
	    sizeof(stat));

	memset(name, 0, sizeof(name));
	if (stat == 0) {
		n = desc.d_name;
		for (i = 5; i >= 0; i--) {
			name[i] = (n & 0xf) + '0';
			n >>= 4;
		}
	}

	switch (ha->ha_id) {
	case CT7946ID:
		if (memcmp(name, "079450", 6) == 0)
			return 0;		/* not really a 7946 */
		/* fall into... */
	case CT9144ID:
	case CT9145ID:
	case CT35401ID:
		type = CT9144;
		canstream = 1;
		break;

	case CT7912PID:
	case CT7914PID:
		type = CT88140;
		break;
	}

	if (sc != NULL) {
		sc->sc_type = type;
		sc->sc_flags = canstream ? CTF_CANSTREAM : 0;
		aprint_normal(": %s %stape\n", ctinfo[id].desc,
		    canstream ? "streaming " : "");
	}

	return 1;
}

static void
ctreset(struct ct_softc *sc)
{
	int ctlr, slave;
	uint8_t stat;

	ctlr = device_unit(device_parent(sc->sc_dev));
	slave = sc->sc_slave;

	sc->sc_clear.unit = C_SUNIT(sc->sc_punit);
	sc->sc_clear.cmd = C_CLEAR;
	hpibsend(ctlr, slave, C_TCMD, &sc->sc_clear, sizeof(sc->sc_clear));
	hpibswait(ctlr, slave);
	hpibrecv(ctlr, slave, C_QSTAT, &stat, sizeof(stat));

	sc->sc_src.unit = C_SUNIT(CTCTLR);
	sc->sc_src.nop = C_NOP;
	sc->sc_src.cmd = C_SREL;
	sc->sc_src.param = C_REL;
	hpibsend(ctlr, slave, C_CMD, &sc->sc_src, sizeof(sc->sc_src));
	hpibswait(ctlr, slave);
	hpibrecv(ctlr, slave, C_QSTAT, &stat, sizeof(stat));

	sc->sc_ssmc.unit = C_SUNIT(sc->sc_punit);
	sc->sc_ssmc.cmd = C_SSM;
	sc->sc_ssmc.refm = REF_MASK;
	sc->sc_ssmc.fefm = FEF_MASK;
	sc->sc_ssmc.aefm = AEF_MASK;
	sc->sc_ssmc.iefm = IEF_MASK;
	hpibsend(ctlr, slave, C_CMD, &sc->sc_ssmc, sizeof(sc->sc_ssmc));
	hpibswait(ctlr, slave);
	hpibrecv(ctlr, slave, C_QSTAT, &stat, sizeof(stat));

	sc->sc_soptc.unit = C_SUNIT(sc->sc_punit);
	sc->sc_soptc.nop = C_NOP;
	sc->sc_soptc.cmd = C_SOPT;
	sc->sc_soptc.opt = C_SPAR;
	hpibsend(ctlr, slave, C_CMD, &sc->sc_soptc, sizeof(sc->sc_soptc));
	hpibswait(ctlr, slave);
	hpibrecv(ctlr, slave, C_QSTAT, &stat, sizeof(stat));
}

/*ARGSUSED*/
static int
ctopen(dev_t dev, int flag, int type, struct lwp *l)
{
	struct ct_softc *sc;
	uint8_t stat;
	int cc, ctlr, slave;

	sc = device_lookup_private(&ct_cd, UNIT(dev));
	if (sc == NULL)
		return ENXIO;

	if ((sc->sc_flags & CTF_ALIVE) == 0)
		return ENXIO;

	if (sc->sc_flags & CTF_OPEN)
		return EBUSY;

	ctlr = device_unit(device_parent(sc->sc_dev));
	slave = sc->sc_slave;

	sc->sc_soptc.unit = C_SUNIT(sc->sc_punit);
	sc->sc_soptc.nop = C_NOP;
	sc->sc_soptc.cmd = C_SOPT;
	if ((dev & CT_STREAM) && (sc->sc_flags & CTF_CANSTREAM))
		sc->sc_soptc.opt = C_SPAR | C_IMRPT;
	else
		sc->sc_soptc.opt = C_SPAR;

	/*
	 * Check the return of hpibsend() and hpibswait().
	 * Drive could be loading/unloading a tape. If not checked,
	 * driver hangs.
	 */
	cc = hpibsend(ctlr, slave, C_CMD, &sc->sc_soptc, sizeof(sc->sc_soptc));
	if (cc != sizeof(sc->sc_soptc))
		return EBUSY;

	hpibswait(ctlr, slave);
	cc = hpibrecv(ctlr, slave, C_QSTAT, &stat, sizeof(stat));
	if (cc != sizeof(stat))
		return EBUSY;

	sc->sc_tpr = tprintf_open(l->l_proc);
	sc->sc_flags |= CTF_OPEN;
	return 0;
}

/*ARGSUSED*/
static int
ctclose(dev_t dev, int flag, int fmt, struct lwp *l)
{
	struct ct_softc *sc = device_lookup_private(&ct_cd,UNIT(dev));

	if ((sc->sc_flags & (CTF_WRT|CTF_WRTTN)) == (CTF_WRT|CTF_WRTTN) &&
	    (sc->sc_flags & CTF_EOT) == 0 ) { /* XXX return error if EOT ?? */
		ctcommand(dev, MTWEOF, 2);
		ctcommand(dev, MTBSR, 1);
		if (sc->sc_eofp == EOFS - 1)
			sc->sc_eofs[EOFS - 1]--;
		else
			sc->sc_eofp--;
#ifdef DEBUG
		if(ctdebug & CT_BSF)
			printf("%s: ctclose backup eofs prt %d blk %d\n",
			    device_xname(sc->sc_dev), sc->sc_eofp,
			    sc->sc_eofs[sc->sc_eofp]);
#endif
	}
	if ((minor(dev) & CT_NOREW) == 0)
		ctcommand(dev, MTREW, 1);
	sc->sc_flags &= ~(CTF_OPEN | CTF_WRT | CTF_WRTTN);
	tprintf_close(sc->sc_tpr);
#ifdef DEBUG
	if (ctdebug & CDB_FILES)
		printf("ctclose: flags %x\n", sc->sc_flags);
#endif
	return 0;	/* XXX */
}

static void
ctcommand(dev_t dev, int cmd, int cnt)
{
	struct ct_softc *sc = device_lookup_private(&ct_cd,UNIT(dev));
	struct buf *bp = &sc->sc_bufstore;
	struct buf *nbp = 0;

	if (cmd == MTBSF && sc->sc_eofp == EOFS - 1) {
		cnt = sc->sc_eofs[EOFS - 1] - cnt;
		ctcommand(dev, MTREW, 1);
		ctcommand(dev, MTFSF, cnt);
		cnt = 2;
		cmd = MTBSR;
	}

	if (cmd == MTBSF && sc->sc_eofp - cnt < 0) {
		cnt = 1;
		cmd = MTREW;
	}

	sc->sc_flags |= CTF_CMD;
	sc->sc_bp = bp;
	sc->sc_cmd = cmd;
	bp->b_dev = dev;
	if (cmd == MTFSF) {
		nbp = (struct buf *)geteblk(MAXBSIZE);
		bp->b_data = nbp->b_data;
		bp->b_bcount = MAXBSIZE;
	}

	while (cnt-- > 0) {
		bp->b_cflags = BC_BUSY;
		if (cmd == MTBSF) {
			sc->sc_blkno = sc->sc_eofs[sc->sc_eofp];
			sc->sc_eofp--;
#ifdef DEBUG
			if (ctdebug & CT_BSF)
				printf("%s: backup eof pos %d blk %d\n",
				    device_xname(sc->sc_dev), sc->sc_eofp,
				    sc->sc_eofs[sc->sc_eofp]);
#endif
		}
		ctstrategy(bp);
		biowait(bp);
	}
	bp->b_flags = 0;
	sc->sc_flags &= ~CTF_CMD;
	if (nbp)
		brelse(nbp, 0);
}

static void
ctstrategy(struct buf *bp)
{
	int s;
	struct ct_softc *sc;

	sc = device_lookup_private(&ct_cd, UNIT(bp->b_dev));

	s = splbio();
	bufq_put(sc->sc_tab, bp);
	if (sc->sc_active == 0) {
		sc->sc_active = 1;
		ctustart(sc);
	}
	splx(s);
}

static void
ctustart(struct ct_softc *sc)
{
	struct buf *bp;

	bp = bufq_peek(sc->sc_tab);
	sc->sc_addr = bp->b_data;
	sc->sc_resid = bp->b_bcount;
	if (hpibreq(device_parent(sc->sc_dev), &sc->sc_hq))
		ctstart(sc);
}

static void
ctstart(void *arg)
{
	struct ct_softc *sc = arg;
	struct buf *bp;
	int i, ctlr, slave;

	ctlr = device_unit(device_parent(sc->sc_dev));
	slave = sc->sc_slave;

	bp = bufq_peek(sc->sc_tab);
	if ((sc->sc_flags & CTF_CMD) && sc->sc_bp == bp) {
		switch(sc->sc_cmd) {
		case MTFSF:
			bp->b_flags |= B_READ;
			goto mustio;

		case MTBSF:
			goto gotaddr;

		case MTOFFL:
			sc->sc_blkno = 0;
			sc->sc_ul.unit = C_SUNIT(sc->sc_punit);
			sc->sc_ul.cmd = C_UNLOAD;
			hpibsend(ctlr, slave, C_CMD, &sc->sc_ul,
			    sizeof(sc->sc_ul));
			break;

		case MTWEOF:
			sc->sc_blkno++;
			sc->sc_flags |= CTF_WRT;
			sc->sc_wfm.unit = C_SUNIT(sc->sc_punit);
			sc->sc_wfm.cmd = C_WFM;
			hpibsend(ctlr, slave, C_CMD, &sc->sc_wfm,
			    sizeof(sc->sc_wfm));
			ctaddeof(sc);
			break;

		case MTBSR:
			sc->sc_blkno--;
			goto gotaddr;

		case MTFSR:
			sc->sc_blkno++;
			goto gotaddr;

		case MTREW:
			sc->sc_blkno = 0;
#ifdef DEBUG
			if(ctdebug & CT_BSF)
				printf("%s: clearing eofs\n",
				    device_xname(sc->sc_dev));
#endif
			for (i=0; i<EOFS; i++)
				sc->sc_eofs[i] = 0;
			sc->sc_eofp = 0;

gotaddr:
			sc->sc_ioc.saddr = C_SADDR;
			sc->sc_ioc.addr0 = 0;
			sc->sc_ioc.addr = sc->sc_blkno;
			sc->sc_ioc.unit = C_SUNIT(sc->sc_punit);
			sc->sc_ioc.nop2 = C_NOP;
			sc->sc_ioc.slen = C_SLEN;
			sc->sc_ioc.len = 0;
			sc->sc_ioc.nop3 = C_NOP;
			sc->sc_ioc.cmd = C_READ;
			hpibsend(ctlr, slave, C_CMD, &sc->sc_ioc,
			    sizeof(sc->sc_ioc));
			break;
		}
	} else {
mustio:
		if ((bp->b_flags & B_READ) &&
		    sc->sc_flags & (CTF_BEOF|CTF_EOT)) {
#ifdef DEBUG
			if (ctdebug & CDB_FILES)
				printf("ctstart: before flags %x\n",
				    sc->sc_flags);
#endif
			if (sc->sc_flags & CTF_BEOF) {
				sc->sc_flags &= ~CTF_BEOF;
				sc->sc_flags |= CTF_AEOF;
#ifdef DEBUG
				if (ctdebug & CDB_FILES)
					printf("ctstart: after flags %x\n",
					    sc->sc_flags);
#endif
			}
			bp->b_resid = bp->b_bcount;
			ctdone(sc, bp);
			return;
		}
		sc->sc_flags |= CTF_IO;
		sc->sc_ioc.unit = C_SUNIT(sc->sc_punit);
		sc->sc_ioc.saddr = C_SADDR;
		sc->sc_ioc.addr0 = 0;
		sc->sc_ioc.addr = sc->sc_blkno;
		sc->sc_ioc.nop2 = C_NOP;
		sc->sc_ioc.slen = C_SLEN;
		sc->sc_ioc.len = sc->sc_resid;
		sc->sc_ioc.nop3 = C_NOP;
		if (bp->b_flags & B_READ)
			sc->sc_ioc.cmd = C_READ;
		else {
			sc->sc_ioc.cmd = C_WRITE;
			sc->sc_flags |= (CTF_WRT | CTF_WRTTN);
		}
		hpibsend(ctlr, slave, C_CMD, &sc->sc_ioc, sizeof(sc->sc_ioc));
	}
	hpibawait(ctlr);
}

static void
ctgo(void *arg)
{
	struct ct_softc *sc = arg;
	struct buf *bp;
	int rw;

	bp = bufq_peek(sc->sc_tab);
	rw = bp->b_flags & B_READ;
	hpibgo(device_unit(device_parent(sc->sc_dev)), sc->sc_slave, C_EXEC,
	    sc->sc_addr, sc->sc_resid, rw, rw != 0);
}

/*
 * Hideous grue to handle EOF/EOT (mostly for reads)
 */
static void
cteof(struct ct_softc *sc, struct buf *bp)
{
	long blks;

	/*
	 * EOT on a write is an error.
	 */
	if ((bp->b_flags & B_READ) == 0) {
		bp->b_resid = bp->b_bcount;
		bp->b_error = ENOSPC;
		sc->sc_flags |= CTF_EOT;
		return;
	}
	/*
	 * Use returned block position to determine how many blocks
	 * we really read and update b_resid.
	 */
	blks = sc->sc_stat.c_blk - sc->sc_blkno - 1;
#ifdef DEBUG
	if (ctdebug & CDB_FILES)
		printf("cteof: bc %d oblk %d nblk %ld read %ld, resid %ld\n",
		       bp->b_bcount, sc->sc_blkno, sc->sc_stat.c_blk,
		       blks, bp->b_bcount - CTKTOB(blks));
#endif
	if (blks == -1) { /* 9145 on EOF does not change sc_stat.c_blk */
		blks = 0;
		sc->sc_blkno++;
	}
	else {
		sc->sc_blkno = sc->sc_stat.c_blk;
	}
	bp->b_resid = bp->b_bcount - CTKTOB(blks);
	/*
	 * If we are at physical EOV or were after an EOF,
	 * we are now at logical EOT.
	 */
	if ((sc->sc_stat.c_aef & AEF_EOV) ||
	    (sc->sc_flags & CTF_AEOF)) {
		sc->sc_flags |= CTF_EOT;
		sc->sc_flags &= ~(CTF_AEOF|CTF_BEOF);
	}
	/*
	 * If we were before an EOF or we have just completed a FSF,
	 * we are now after EOF.
	 */
	else if ((sc->sc_flags & CTF_BEOF) ||
		 ((sc->sc_flags & CTF_CMD) && sc->sc_cmd == MTFSF)) {
		sc->sc_flags |= CTF_AEOF;
		sc->sc_flags &= ~CTF_BEOF;
	}
	/*
	 * Otherwise if we read something we are now before EOF
	 * (and no longer after EOF).
	 */
	else if (blks) {
		sc->sc_flags |= CTF_BEOF;
		sc->sc_flags &= ~CTF_AEOF;
	}
	/*
	 * Finally, if we didn't read anything we just passed an EOF
	 */
	else
		sc->sc_flags |= CTF_AEOF;
#ifdef DEBUG
	if (ctdebug & CDB_FILES)
		printf("cteof: leaving flags %x\n", sc->sc_flags);
#endif
}

/* ARGSUSED */
static void
ctintr(void *arg)
{
	struct ct_softc *sc = arg;
	struct buf *bp;
	uint8_t stat;
	int ctlr, slave;

	ctlr = device_unit(device_parent(sc->sc_dev));
	slave = sc->sc_slave;

	bp = bufq_peek(sc->sc_tab);
	if (bp == NULL) {
		printf("%s: bp == NULL\n", device_xname(sc->sc_dev));
		return;
	}
	if (sc->sc_flags & CTF_IO) {
		sc->sc_flags &= ~CTF_IO;
		if (hpibustart(ctlr))
			ctgo(sc);
		return;
	}
	if ((sc->sc_flags & CTF_STATWAIT) == 0) {
		if (hpibpptest(ctlr, slave) == 0) {
			sc->sc_flags |= CTF_STATWAIT;
			hpibawait(ctlr);
			return;
		}
	} else
		sc->sc_flags &= ~CTF_STATWAIT;
	hpibrecv(ctlr, slave, C_QSTAT, &stat, 1);
#ifdef DEBUG
	if (ctdebug & CDB_FILES)
		printf("ctintr: before flags %x\n", sc->sc_flags);
#endif
	if (stat) {
		sc->sc_rsc.unit = C_SUNIT(sc->sc_punit);
		sc->sc_rsc.cmd = C_STATUS;
		hpibsend(ctlr, slave, C_CMD, &sc->sc_rsc, sizeof(sc->sc_rsc));
		hpibrecv(ctlr, slave, C_EXEC, &sc->sc_stat,
		    sizeof(sc->sc_stat));
		hpibrecv(ctlr, slave, C_QSTAT, &stat, 1);
#ifdef DEBUG
		if (ctdebug & CDB_FILES)
			printf("ctintr: return stat 0x%x, A%x F%x blk %ld\n",
			       stat, sc->sc_stat.c_aef,
			       sc->sc_stat.c_fef, sc->sc_stat.c_blk);
#endif
		if (stat == 0) {
			if (sc->sc_stat.c_aef & (AEF_EOF | AEF_EOV)) {
				cteof(sc, bp);
				ctaddeof(sc);
				goto done;
			}
			if (sc->sc_stat.c_fef & FEF_PF) {
				ctreset(sc);
				ctstart(sc);
				return;
			}
			if (sc->sc_stat.c_fef & FEF_REXMT) {
				ctstart(sc);
				return;
			}
			if (sc->sc_stat.c_aef & 0x5800) {
				if (sc->sc_stat.c_aef & 0x4000)
					tprintf(sc->sc_tpr,
					    "%s: uninitialized media\n",
					    device_xname(sc->sc_dev));
				if (sc->sc_stat.c_aef & 0x1000)
					tprintf(sc->sc_tpr,
					    "%s: not ready\n",
					    device_xname(sc->sc_dev));
				if (sc->sc_stat.c_aef & 0x0800)
					tprintf(sc->sc_tpr,
					    "%s: write protect\n",
					    device_xname(sc->sc_dev));
			} else {
				printf("%s err: v%d u%d ru%d bn%ld, ",
				    device_xname(sc->sc_dev),
				       (sc->sc_stat.c_vu >> 4) & 0xF,
				       sc->sc_stat.c_vu & 0xF,
				       sc->sc_stat.c_pend,
				       sc->sc_stat.c_blk);
				printf("R0x%x F0x%x A0x%x I0x%x\n",
				       sc->sc_stat.c_ref,
				       sc->sc_stat.c_fef,
				       sc->sc_stat.c_aef,
				       sc->sc_stat.c_ief);
			}
		} else
			printf("%s: request status failed\n",
			    device_xname(sc->sc_dev));
		bp->b_error = EIO;
		goto done;
	} else
		bp->b_resid = 0;
	if (sc->sc_flags & CTF_CMD) {
		switch (sc->sc_cmd) {
		case MTFSF:
			sc->sc_flags &= ~(CTF_BEOF|CTF_AEOF);
			sc->sc_blkno += CTBTOK(sc->sc_resid);
			ctstart(sc);
			return;
		case MTBSF:
			sc->sc_flags &= ~(CTF_AEOF|CTF_BEOF|CTF_EOT);
			break;
		case MTBSR:
			sc->sc_flags &= ~CTF_BEOF;
			if (sc->sc_flags & CTF_EOT) {
				sc->sc_flags |= CTF_AEOF;
				sc->sc_flags &= ~CTF_EOT;
			} else if (sc->sc_flags & CTF_AEOF) {
				sc->sc_flags |= CTF_BEOF;
				sc->sc_flags &= ~CTF_AEOF;
			}
			break;
		case MTWEOF:
			sc->sc_flags &= ~CTF_BEOF;
			if (sc->sc_flags & (CTF_AEOF|CTF_EOT)) {
				sc->sc_flags |= CTF_EOT;
				sc->sc_flags &= ~CTF_AEOF;
			} else
				sc->sc_flags |= CTF_AEOF;
			break;
		case MTREW:
		case MTOFFL:
			sc->sc_flags &= ~(CTF_BEOF|CTF_AEOF|CTF_EOT);
			break;
		}
	} else {
		sc->sc_flags &= ~CTF_AEOF;
		sc->sc_blkno += CTBTOK(sc->sc_resid);
	}
done:
#ifdef DEBUG
	if (ctdebug & CDB_FILES)
		printf("ctintr: after flags %x\n", sc->sc_flags);
#endif
	ctdone(sc, bp);
}

static void
ctdone(struct ct_softc *sc, struct buf *bp)
{

	(void)bufq_get(sc->sc_tab);
	biodone(bp);
	hpibfree(device_parent(sc->sc_dev), &sc->sc_hq);
	if (bufq_peek(sc->sc_tab) == NULL) {
		sc->sc_active = 0;
		return;
	}
	ctustart(sc);
}

static int
ctread(dev_t dev, struct uio *uio, int flags)
{

	return physio(ctstrategy, NULL, dev, B_READ, minphys, uio);
}

static int
ctwrite(dev_t dev, struct uio *uio, int flags)
{

	/* XXX: check for hardware write-protect? */
	return physio(ctstrategy, NULL, dev, B_WRITE, minphys, uio);
}

/*ARGSUSED*/
static int
ctioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
	struct mtop *op;
	int cnt;

	switch (cmd) {

	case MTIOCTOP:
		op = (struct mtop *)data;
		switch(op->mt_op) {

		case MTWEOF:
		case MTFSF:
		case MTBSR:
		case MTBSF:
		case MTFSR:
			cnt = op->mt_count;
			break;

		case MTREW:
		case MTOFFL:
			cnt = 1;
			break;

		default:
			return EINVAL;
		}
		ctcommand(dev, op->mt_op, cnt);
		break;

	case MTIOCGET:
		break;

	default:
		return EINVAL;
	}
	return 0;
}

static void
ctaddeof(struct ct_softc *sc)
{

	if (sc->sc_eofp == EOFS - 1)
		sc->sc_eofs[EOFS - 1]++;
	else {
		sc->sc_eofp++;
		if (sc->sc_eofp == EOFS - 1)
			sc->sc_eofs[EOFS - 1] = EOFS;
		else
			/* save blkno */
			sc->sc_eofs[sc->sc_eofp] = sc->sc_blkno - 1;
	}
#ifdef DEBUG
	if (ctdebug & CT_BSF)
		printf("%s: add eof pos %d blk %d\n",
		       device_xname(sc->sc_dev), sc->sc_eofp,
		       sc->sc_eofs[sc->sc_eofp]);
#endif
}