/*      $NetBSD: fhpib.c,v 1.44 2024/01/16 05:48:28 thorpej 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.
 *
 *      @(#)fhpib.c     8.2 (Berkeley) 1/12/94
 */

/*
 * 98625A/B HPIB driver
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fhpib.c,v 1.44 2024/01/16 05:48:28 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/buf.h>
#include <sys/device.h>

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

#include <hp300/dev/diovar.h>
#include <hp300/dev/diodevs.h>

#include <hp300/dev/dmavar.h>

#include <hp300/dev/fhpibreg.h>
#include <hp300/dev/hpibvar.h>

/*
 * Inline version of fhpibwait to be used in places where
 * we don't worry about getting hung.
 */
#define FHPIBWAIT(hd, m)        while (((hd)->hpib_intr & (m)) == 0) DELAY(1)

#ifdef DEBUG
int     fhpibdebugunit = -1;
int     fhpibdebug = 0;
#define FDB_FAIL        0x01
#define FDB_DMA         0x02
#define FDB_WAIT        0x04
#define FDB_PPOLL       0x08

int     dopriodma = 0;  /* use high priority DMA */
int     doworddma = 1;  /* non-zero if we should attempt word DMA */
int     doppollint = 1; /* use ppoll interrupts instead of watchdog */
int     fhpibppolldelay = 50;
#endif

static void     fhpibifc(struct fhpibdevice *);
static void     fhpibdmadone(void *);
static int      fhpibwait(struct fhpibdevice *, int);

static void     fhpibreset(struct hpibbus_softc *);
static int      fhpibsend(struct hpibbus_softc *, int, int, void *, int);
static int      fhpibrecv(struct hpibbus_softc *, int, int, void *, int);
static int      fhpibppoll(struct hpibbus_softc *);
static void     fhpibppwatch(void *);
static void     fhpibgo(struct hpibbus_softc *, int, int, void *, int, int,
                    int);
static void     fhpibdone(struct hpibbus_softc *);
static int      fhpibintr(void *);

/*
 * Our controller ops structure.
 */
static struct hpib_controller fhpib_controller = {
        fhpibreset,
        fhpibsend,
        fhpibrecv,
        fhpibppoll,
        fhpibppwatch,
        fhpibgo,
        fhpibdone,
        fhpibintr
};

struct fhpib_softc {
        device_t sc_dev;                /* generic device glue */
        struct fhpibdevice *sc_regs;    /* device registers */
        int     sc_cmd;
        struct hpibbus_softc *sc_hpibbus; /* XXX */
        struct callout sc_dmadone_ch;
        struct callout sc_ppwatch_ch;
};

static int      fhpibmatch(device_t, cfdata_t, void *);
static void     fhpibattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(fhpib, sizeof(struct fhpib_softc),
    fhpibmatch, fhpibattach, NULL, NULL);

static int
fhpibmatch(device_t parent, cfdata_t cf, void *aux)
{
        struct dio_attach_args *da = aux;

        if (da->da_id == DIO_DEVICE_ID_FHPIB)
                return 1;

        return 0;
}

static void
fhpibattach(device_t parent, device_t self, void *aux)
{
        struct fhpib_softc *sc = device_private(self);
        struct dio_attach_args *da = aux;
        struct hpibdev_attach_args ha;
        bus_space_handle_t bsh;

        sc->sc_dev = self;
        if (bus_space_map(da->da_bst, da->da_addr, da->da_size, 0, &bsh)) {
                aprint_error(": can't map registers\n");
                return;
        }
        sc->sc_regs = bus_space_vaddr(da->da_bst, bsh);

        aprint_normal(": %s\n", DIO_DEVICE_DESC_FHPIB);

        /* Establish the interrupt handler. */
        (void)dio_intr_establish(fhpibintr, sc, da->da_ipl, ISRPRI_BIO);

        callout_init(&sc->sc_dmadone_ch, 0);
        callout_init(&sc->sc_ppwatch_ch, 0);

        ha.ha_ops = &fhpib_controller;
        ha.ha_type = HPIBC;                     /* XXX */
        ha.ha_ba = HPIBC_BA;
        ha.ha_softcpp = &sc->sc_hpibbus;        /* XXX */
        (void)config_found(self, &ha, hpibdevprint, CFARGS_NONE);
}

static void
fhpibreset(struct hpibbus_softc *hs)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;

        hd->hpib_cid = 0xFF;
        DELAY(100);
        hd->hpib_cmd = CT_8BIT;
        hd->hpib_ar = AR_ARONC;
        fhpibifc(hd);
        hd->hpib_ie = IDS_IE;
        hd->hpib_data = C_DCL;
        DELAY(100000);
        /*
         * See if we can do word DMA.
         * If so, we should be able to write and read back the appropos bit.
         */
        hd->hpib_ie |= IDS_WDMA;
        if (hd->hpib_ie & IDS_WDMA) {
                hd->hpib_ie &= ~IDS_WDMA;
                hs->sc_flags |= HPIBF_DMA16;
#ifdef DEBUG
                if (fhpibdebug & FDB_DMA)
                        printf("fhpibtype: %s has word DMA\n",
                            device_xname(sc->sc_dev));
#endif
        }
}

static void
fhpibifc(struct fhpibdevice *hd)
{

        hd->hpib_cmd |= CT_IFC;
        hd->hpib_cmd |= CT_INITFIFO;
        DELAY(100);
        hd->hpib_cmd &= ~CT_IFC;
        hd->hpib_cmd |= CT_REN;
        hd->hpib_stat = ST_ATN;
}

static int
fhpibsend(struct hpibbus_softc *hs, int slave, int sec, void *ptr, int origcnt)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        int cnt = origcnt;
        int timo;
        char *addr = ptr;

        hd->hpib_stat = 0;
        hd->hpib_imask = IM_IDLE | IM_ROOM;
        if (fhpibwait(hd, IM_IDLE) < 0)
                goto senderr;
        hd->hpib_stat = ST_ATN;
        hd->hpib_data = C_UNL;
        hd->hpib_data = C_TAG + hs->sc_ba;
        hd->hpib_data = C_LAG + slave;
        if (sec < 0) {
                if (sec == -2)          /* selected device clear KLUDGE */
                        hd->hpib_data = C_SDC;
        } else
                hd->hpib_data = C_SCG + sec;
        if (fhpibwait(hd, IM_IDLE) < 0)
                goto senderr;
        if (cnt) {
                hd->hpib_stat = ST_WRITE;
                while (--cnt) {
                        hd->hpib_data = *addr++;
                        timo = hpibtimeout;
                        while ((hd->hpib_intr & IM_ROOM) == 0) {
                                if (--timo <= 0)
                                        goto senderr;
                                DELAY(1);
                        }
                }
                hd->hpib_stat = ST_EOI;
                hd->hpib_data = *addr;
                FHPIBWAIT(hd, IM_ROOM);
                hd->hpib_stat = ST_ATN;
                /* XXX: HP-UX claims bug with CS80 transparent messages */
                if (sec == 0x12)
                        DELAY(150);
                hd->hpib_data = C_UNL;
                (void) fhpibwait(hd, IM_IDLE);
        }
        hd->hpib_imask = 0;
        return origcnt;

senderr:
        hd->hpib_imask = 0;
        fhpibifc(hd);
#ifdef DEBUG
        if (fhpibdebug & FDB_FAIL) {
                printf("%s: fhpibsend failed: slave %d, sec %x, ",
                    device_xname(sc->sc_dev), slave, sec);
                printf("sent %d of %d bytes\n", origcnt-cnt-1, origcnt);
        }
#endif
        return origcnt - cnt - 1;
}

static int
fhpibrecv(struct hpibbus_softc *hs, int slave, int sec, void *ptr, int origcnt)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        int cnt = origcnt;
        int timo;
        char *addr = ptr;

        /*
         * Slave < 0 implies continuation of a previous receive
         * that probably timed out.
         */
        if (slave >= 0) {
                hd->hpib_stat = 0;
                hd->hpib_imask = IM_IDLE | IM_ROOM | IM_BYTE;
                if (fhpibwait(hd, IM_IDLE) < 0)
                        goto recverror;
                hd->hpib_stat = ST_ATN;
                hd->hpib_data = C_UNL;
                hd->hpib_data = C_LAG + hs->sc_ba;
                hd->hpib_data = C_TAG + slave;
                if (sec != -1)
                        hd->hpib_data = C_SCG + sec;
                if (fhpibwait(hd, IM_IDLE) < 0)
                        goto recverror;
                hd->hpib_stat = ST_READ0;
                hd->hpib_data = 0;
        }
        if (cnt) {
                while (--cnt >= 0) {
                        timo = hpibtimeout;
                        while ((hd->hpib_intr & IM_BYTE) == 0) {
                                if (--timo == 0)
                                        goto recvbyteserror;
                                DELAY(1);
                        }
                        *addr++ = hd->hpib_data;
                }
                FHPIBWAIT(hd, IM_ROOM);
                hd->hpib_stat = ST_ATN;
                hd->hpib_data = (slave == 31) ? C_UNA : C_UNT;
                (void) fhpibwait(hd, IM_IDLE);
        }
        hd->hpib_imask = 0;
        return origcnt;

recverror:
        fhpibifc(hd);
recvbyteserror:
        hd->hpib_imask = 0;
#ifdef DEBUG
        if (fhpibdebug & FDB_FAIL) {
                printf("%s: fhpibrecv failed: slave %d, sec %x, ",
                    device_xname(sc->sc_dev), slave, sec);
                printf("got %d of %d bytes\n", origcnt-cnt-1, origcnt);
        }
#endif
        return origcnt - cnt - 1;
}

static void
fhpibgo(struct hpibbus_softc *hs, int slave, int sec, void *ptr, int count,
    int rw, int timo)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        int i;
        char *addr = ptr;
        int flags = 0;

        hs->sc_flags |= HPIBF_IO;
        if (timo)
                hs->sc_flags |= HPIBF_TIMO;
        if (rw == B_READ)
                hs->sc_flags |= HPIBF_READ;
#ifdef DEBUG
        else if (hs->sc_flags & HPIBF_READ) {
                printf("%s: HPIBF_READ still set\n", __func__);
                hs->sc_flags &= ~HPIBF_READ;
        }
#endif
        hs->sc_count = count;
        hs->sc_addr = addr;
#ifdef DEBUG
        /* fhpibtransfer[unit]++;                       XXX */
#endif
        if ((hs->sc_flags & HPIBF_DMA16) &&
            ((int)addr & 1) == 0 && count && (count & 1) == 0
#ifdef DEBUG
            && doworddma
#endif
            ) {
#ifdef DEBUG
                /* fhpibworddma[unit]++;                XXX */
#endif
                flags |= DMAGO_WORD;
                hd->hpib_latch = 0;
        }
#ifdef DEBUG
        if (dopriodma)
                flags |= DMAGO_PRI;
#endif
        if (hs->sc_flags & HPIBF_READ) {
                sc->sc_cmd = CT_REN | CT_8BIT;
                hs->sc_curcnt = count;
                dmago(hs->sc_dq->dq_chan, addr, count, flags|DMAGO_READ);
                if (fhpibrecv(hs, slave, sec, 0, 0) < 0) {
#ifdef DEBUG
                        printf("%s: recv failed, retrying...\n", __func__);
#endif
                        (void)fhpibrecv(hs, slave, sec, 0, 0);
                }
                i = hd->hpib_cmd;
                hd->hpib_cmd = sc->sc_cmd;
                hd->hpib_ie = IDS_DMA(hs->sc_dq->dq_chan) |
                        ((flags & DMAGO_WORD) ? IDS_WDMA : 0);
                __USE(i);
                return;
        }
        sc->sc_cmd = CT_REN | CT_8BIT | CT_FIFOSEL;
        if (count < hpibdmathresh) {
#ifdef DEBUG
                /* fhpibnondma[unit]++;                 XXX */
                if (flags & DMAGO_WORD)
                        /* fhpibworddma[unit]--;        XXX */ ;
#endif
                hs->sc_curcnt = count;
                (void) fhpibsend(hs, slave, sec, addr, count);
                fhpibdone(hs);
                return;
        }
        count -= (flags & DMAGO_WORD) ? 2 : 1;
        hs->sc_curcnt = count;
        dmago(hs->sc_dq->dq_chan, addr, count, flags);
        if (fhpibsend(hs, slave, sec, 0, 0) < 0) {
#ifdef DEBUG
                printf("%s: send failed, retrying...\n", __func__);
#endif
                (void)fhpibsend(hs, slave, sec, 0, 0);
        }
        i = hd->hpib_cmd;
        hd->hpib_cmd = sc->sc_cmd;
        hd->hpib_ie = IDS_DMA(hs->sc_dq->dq_chan) | IDS_WRITE |
                ((flags & DMAGO_WORD) ? IDS_WDMA : 0);
        __USE(i);
}

/*
 * A DMA read can finish but the device can still be waiting (MAG-tape
 * with more data than we're waiting for).  This timeout routine
 * takes care of that.  Somehow, the thing gets hosed.  For now, since
 * this should be a very rare occurrence, we RESET it.
 */
static void
fhpibdmadone(void *arg)
{
        struct hpibbus_softc *hs = arg;
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        int s = splbio();

        if (hs->sc_flags & HPIBF_IO) {
                struct fhpibdevice *hd = sc->sc_regs;
                struct hpibqueue *hq;

                hd->hpib_imask = 0;
                hd->hpib_cid = 0xFF;
                DELAY(100);
                hd->hpib_cmd = CT_8BIT;
                hd->hpib_ar = AR_ARONC;
                fhpibifc(hd);
                hd->hpib_ie = IDS_IE;
                hs->sc_flags &= ~(HPIBF_DONE|HPIBF_IO|HPIBF_READ|HPIBF_TIMO);
                dmafree(hs->sc_dq);

                hq = TAILQ_FIRST(&hs->sc_queue);
                (hq->hq_intr)(hq->hq_softc);
        }
        splx(s);
}

static void
fhpibdone(struct hpibbus_softc *hs)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        char *addr;
        int cnt;

        cnt = hs->sc_curcnt;
        hs->sc_addr += cnt;
        hs->sc_count -= cnt;
#ifdef DEBUG
        if ((fhpibdebug & FDB_DMA) &&
            fhpibdebugunit == device_unit(sc->sc_dev))
                printf("%s: addr %p cnt %d\n",
                    __func__, hs->sc_addr, hs->sc_count);
#endif
        if (hs->sc_flags & HPIBF_READ) {
                hd->hpib_imask = IM_IDLE | IM_BYTE;
                if (hs->sc_flags & HPIBF_TIMO)
                        callout_reset(&sc->sc_dmadone_ch, hz >> 2,
                            fhpibdmadone, hs);
        } else {
                cnt = hs->sc_count;
                if (cnt) {
                        addr = hs->sc_addr;
                        hd->hpib_imask = IM_IDLE | IM_ROOM;
                        FHPIBWAIT(hd, IM_IDLE);
                        hd->hpib_stat = ST_WRITE;
                        while (--cnt) {
                                hd->hpib_data = *addr++;
                                FHPIBWAIT(hd, IM_ROOM);
                        }
                        hd->hpib_stat = ST_EOI;
                        hd->hpib_data = *addr;
                }
                hd->hpib_imask = IM_IDLE;
        }
        hs->sc_flags |= HPIBF_DONE;
        hd->hpib_stat = ST_IENAB;
        hd->hpib_ie = IDS_IE;
}

static int
fhpibintr(void *arg)
{
        struct fhpib_softc *sc = arg;
        struct hpibbus_softc *hs = sc->sc_hpibbus;
        struct fhpibdevice *hd = sc->sc_regs;
        struct hpibqueue *hq;
        int stat0;

        stat0 = hd->hpib_ids;
        if ((stat0 & (IDS_IE|IDS_IR)) != (IDS_IE|IDS_IR)) {
#ifdef DEBUG
                if ((fhpibdebug & FDB_FAIL) && (stat0 & IDS_IR) &&
                    (hs->sc_flags & (HPIBF_IO|HPIBF_DONE)) != HPIBF_IO)
                        printf("%s: fhpibintr: bad status %x\n",
                            device_xname(sc->sc_dev), stat0);
                /* fhpibbadint[0]++;                    XXX */
#endif
                return 0;
        }
        if ((hs->sc_flags & (HPIBF_IO|HPIBF_DONE)) == HPIBF_IO) {
#ifdef DEBUG
                /* fhpibbadint[1]++;                    XXX */
#endif
                return 0;
        }
#ifdef DEBUG
        if ((fhpibdebug & FDB_DMA) &&
            fhpibdebugunit == device_unit(sc->sc_dev))
                printf("%s: flags %x\n", __func__, hs->sc_flags);
#endif
        hq = TAILQ_FIRST(&hs->sc_queue);
        if (hs->sc_flags & HPIBF_IO) {
                if (hs->sc_flags & HPIBF_TIMO)
                        callout_stop(&sc->sc_dmadone_ch);
                stat0 = hd->hpib_cmd;
                hd->hpib_cmd = sc->sc_cmd & ~CT_8BIT;
                hd->hpib_stat = 0;
                hd->hpib_cmd = CT_REN | CT_8BIT;
                stat0 = hd->hpib_intr;
                hd->hpib_imask = 0;
                hs->sc_flags &= ~(HPIBF_DONE|HPIBF_IO|HPIBF_READ|HPIBF_TIMO);
                dmafree(hs->sc_dq);
                (hq->hq_intr)(hq->hq_softc);
        } else if (hs->sc_flags & HPIBF_PPOLL) {
                stat0 = hd->hpib_intr;
#ifdef DEBUG
                if ((fhpibdebug & FDB_FAIL) &&
                    doppollint && (stat0 & IM_PPRESP) == 0)
                        printf("%s: fhpibintr: bad intr reg %x\n",
                            device_xname(sc->sc_dev), stat0);
#endif
                hd->hpib_stat = 0;
                hd->hpib_imask = 0;
#ifdef DEBUG
                stat0 = fhpibppoll(hs);
                if ((fhpibdebug & FDB_PPOLL) &&
                    fhpibdebugunit == device_unit(sc->sc_dev))
                        printf("%s: got PPOLL status %x\n", __func__, stat0);
                if ((stat0 & (0x80 >> hq->hq_slave)) == 0) {
                        /*
                         * XXX give it another shot (68040)
                         */
                        /* fhpibppollfail[unit]++;      XXX */
                        DELAY(fhpibppolldelay);
                        stat0 = fhpibppoll(hs);
                        if ((stat0 & (0x80 >> hq->hq_slave)) == 0 &&
                            (fhpibdebug & FDB_PPOLL) &&
                            fhpibdebugunit == device_unit(sc->sc_dev))
                                printf("%s: PPOLL: unit %d slave %d stat %x\n",
                                    __func__, device_unit(sc->sc_dev),
                                    hq->hq_slave, stat0);
                }
#endif
                hs->sc_flags &= ~HPIBF_PPOLL;
                (hq->hq_intr)(hq->hq_softc);
        }
        return 1;
}

static int
fhpibppoll(struct hpibbus_softc *hs)
{
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        int ppoll;

        hd->hpib_stat = 0;
        hd->hpib_psense = 0;
        hd->hpib_pmask = 0xFF;
        hd->hpib_imask = IM_PPRESP | IM_PABORT;
        DELAY(25);
        hd->hpib_intr = IM_PABORT;
        ppoll = hd->hpib_data;
        if (hd->hpib_intr & IM_PABORT)
                ppoll = 0;
        hd->hpib_imask = 0;
        hd->hpib_pmask = 0;
        hd->hpib_stat = ST_IENAB;
        return ppoll;
}

static int
fhpibwait(struct fhpibdevice *hd, int x)
{
        int timo = hpibtimeout;

        while ((hd->hpib_intr & x) == 0 && --timo)
                DELAY(1);
        if (timo == 0) {
#ifdef DEBUG
                if (fhpibdebug & FDB_FAIL)
                        printf("%s(%p, %x) timeout\n", __func__, hd, x);
#endif
                return -1;
        }
        return 0;
}

/*
 * XXX: this will have to change if we ever allow more than one
 * pending operation per HP-IB.
 */
static void
fhpibppwatch(void *arg)
{
        struct hpibbus_softc *hs = arg;
        struct fhpib_softc *sc = device_private(device_parent(hs->sc_dev));
        struct fhpibdevice *hd = sc->sc_regs;
        int slave;

        if ((hs->sc_flags & HPIBF_PPOLL) == 0)
                return;
        slave = (0x80 >> TAILQ_FIRST(&hs->sc_queue)->hq_slave);
#ifdef DEBUG
        if (!doppollint) {
                if (fhpibppoll(hs) & slave) {
                        hd->hpib_stat = ST_IENAB;
                        hd->hpib_imask = IM_IDLE | IM_ROOM;
                } else
                        callout_reset(&sc->sc_ppwatch_ch, 1, fhpibppwatch, sc);
                return;
        }
        if ((fhpibdebug & FDB_PPOLL) &&
            device_unit(sc->sc_dev) == fhpibdebugunit)
                printf("%s: sense request on %s\n",
                    __func__, device_xname(sc->sc_dev));
#endif
        hd->hpib_psense = ~slave;
        hd->hpib_pmask = slave;
        hd->hpib_stat = ST_IENAB;
        hd->hpib_imask = IM_PPRESP | IM_PABORT;
        hd->hpib_ie = IDS_IE;
}