/*      $NetBSD: ct.c,v 1.64 2023/04/21 23:01:59 tsutsui 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 1.64 2023/04/21 23:01:59 tsutsui 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));
}

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;
}

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
}

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);
}

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
}