root/sys/dev/ic/siop.c 
/*      $NetBSD: siop.c,v 1.105 2024/02/08 19:44:08 andvar Exp $        */

/*
 * Copyright (c) 2000 Manuel Bouyer.
 *
 * 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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* SYM53c7/8xx PCI-SCSI I/O Processors driver */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: siop.c,v 1.105 2024/02/08 19:44:08 andvar Exp $");

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

#include <machine/endian.h>
#include <sys/bus.h>

#include <dev/microcode/siop/siop.out>

#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsi_message.h>
#include <dev/scsipi/scsipi_all.h>

#include <dev/scsipi/scsiconf.h>

#include <dev/ic/siopreg.h>
#include <dev/ic/siopvar_common.h>
#include <dev/ic/siopvar.h>

#include "opt_siop.h"

/*
#define SIOP_DEBUG
#define SIOP_DEBUG_DR
#define SIOP_DEBUG_INTR
#define SIOP_DEBUG_SCHED
#define SIOP_DUMP_SCRIPT
*/

#define SIOP_STATS

#ifndef SIOP_DEFAULT_TARGET
#define SIOP_DEFAULT_TARGET 7
#endif

/* number of cmd descriptors per block */
#define SIOP_NCMDPB (PAGE_SIZE / sizeof(struct siop_xfer))

/* Number of scheduler slot (needs to match script) */
#define SIOP_NSLOTS 40

void    siop_reset(struct siop_softc *);
void    siop_handle_reset(struct siop_softc *);
int     siop_handle_qtag_reject(struct siop_cmd *);
void    siop_scsicmd_end(struct siop_cmd *);
void    siop_unqueue(struct siop_softc *, int, int);
static void     siop_start(struct siop_softc *, struct siop_cmd *);
void    siop_timeout(void *);
int     siop_scsicmd(struct scsipi_xfer *);
void    siop_scsipi_request(struct scsipi_channel *,
                        scsipi_adapter_req_t, void *);
void    siop_dump_script(struct siop_softc *);
void    siop_morecbd(struct siop_softc *);
struct siop_lunsw *siop_get_lunsw(struct siop_softc *);
void    siop_add_reselsw(struct siop_softc *, int);
void    siop_update_scntl3(struct siop_softc *,
                        struct siop_common_target *);

#ifdef SIOP_STATS
static int siop_stat_intr = 0;
static int siop_stat_intr_shortxfer = 0;
static int siop_stat_intr_sdp = 0;
static int siop_stat_intr_saveoffset = 0;
static int siop_stat_intr_done = 0;
static int siop_stat_intr_xferdisc = 0;
static int siop_stat_intr_lunresel = 0;
static int siop_stat_intr_qfull = 0;
void siop_printstats(void);
#define INCSTAT(x) x++
#else
#define INCSTAT(x)
#endif

static inline void siop_script_sync(struct siop_softc *, int);
static inline void
siop_script_sync(struct siop_softc *sc, int ops)
{

        if ((sc->sc_c.features & SF_CHIP_RAM) == 0)
                bus_dmamap_sync(sc->sc_c.sc_dmat, sc->sc_c.sc_scriptdma, 0,
                    PAGE_SIZE, ops);
}

static inline uint32_t siop_script_read(struct siop_softc *, u_int);
static inline uint32_t
siop_script_read(struct siop_softc *sc, u_int offset)
{

        if (sc->sc_c.features & SF_CHIP_RAM) {
                return bus_space_read_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh,
                    offset * 4);
        } else {
                return siop_ctoh32(&sc->sc_c, sc->sc_c.sc_script[offset]);
        }
}

static inline void siop_script_write(struct siop_softc *, u_int,
        uint32_t);
static inline void
siop_script_write(struct siop_softc *sc, u_int offset, uint32_t val)
{

        if (sc->sc_c.features & SF_CHIP_RAM) {
                bus_space_write_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh,
                    offset * 4, val);
        } else {
                sc->sc_c.sc_script[offset] = siop_htoc32(&sc->sc_c, val);
        }
}

void
siop_attach(struct siop_softc *sc)
{

        if (siop_common_attach(&sc->sc_c) != 0)
                return;

        TAILQ_INIT(&sc->free_list);
        TAILQ_INIT(&sc->cmds);
        TAILQ_INIT(&sc->lunsw_list);
        sc->sc_currschedslot = 0;
#ifdef SIOP_DEBUG
        printf("%s: script size = %d, PHY addr=0x%x, VIRT=%p\n",
            device_xname(sc->sc_c.sc_dev), (int)sizeof(siop_script),
            (uint32_t)sc->sc_c.sc_scriptaddr, sc->sc_c.sc_script);
#endif

        sc->sc_c.sc_adapt.adapt_max_periph = SIOP_NTAG - 1;
        sc->sc_c.sc_adapt.adapt_request = siop_scsipi_request;

        /* Do a bus reset, so that devices fall back to narrow/async */
        siop_resetbus(&sc->sc_c);
        /*
         * siop_reset() will reset the chip, thus clearing pending interrupts
         */
        siop_reset(sc);
#ifdef SIOP_DUMP_SCRIPT
        siop_dump_script(sc);
#endif

        config_found(sc->sc_c.sc_dev, &sc->sc_c.sc_chan, scsiprint, CFARGS_NONE);
}

void
siop_reset(struct siop_softc *sc)
{
        int i, j;
        struct siop_lunsw *lunsw;

        siop_common_reset(&sc->sc_c);

        /* copy and patch the script */
        if (sc->sc_c.features & SF_CHIP_RAM) {
                bus_space_write_region_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh, 0,
                    siop_script, __arraycount(siop_script));
                for (j = 0; j < __arraycount(E_abs_msgin_Used); j++) {
                        bus_space_write_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh,
                            E_abs_msgin_Used[j] * 4,
                            sc->sc_c.sc_scriptaddr + Ent_msgin_space);
                }
                if (sc->sc_c.features & SF_CHIP_LED0) {
                        bus_space_write_region_4(sc->sc_c.sc_ramt,
                            sc->sc_c.sc_ramh,
                            Ent_led_on1, siop_led_on,
                            __arraycount(siop_led_on));
                        bus_space_write_region_4(sc->sc_c.sc_ramt,
                            sc->sc_c.sc_ramh,
                            Ent_led_on2, siop_led_on,
                            __arraycount(siop_led_on));
                        bus_space_write_region_4(sc->sc_c.sc_ramt,
                            sc->sc_c.sc_ramh,
                            Ent_led_off, siop_led_off,
                            __arraycount(siop_led_off));
                }
        } else {
                for (j = 0; j < __arraycount(siop_script); j++) {
                        sc->sc_c.sc_script[j] =
                            siop_htoc32(&sc->sc_c, siop_script[j]);
                }
                for (j = 0; j < __arraycount(E_abs_msgin_Used); j++) {
                        sc->sc_c.sc_script[E_abs_msgin_Used[j]] =
                            siop_htoc32(&sc->sc_c,
                                sc->sc_c.sc_scriptaddr + Ent_msgin_space);
                }
                if (sc->sc_c.features & SF_CHIP_LED0) {
                        for (j = 0; j < __arraycount(siop_led_on); j++)
                                sc->sc_c.sc_script[
                                    Ent_led_on1 / sizeof(siop_led_on[0]) + j
                                    ] = siop_htoc32(&sc->sc_c, siop_led_on[j]);
                        for (j = 0; j < __arraycount(siop_led_on); j++)
                                sc->sc_c.sc_script[
                                    Ent_led_on2 / sizeof(siop_led_on[0]) + j
                                    ] = siop_htoc32(&sc->sc_c, siop_led_on[j]);
                        for (j = 0; j < __arraycount(siop_led_off); j++)
                                sc->sc_c.sc_script[
                                    Ent_led_off / sizeof(siop_led_off[0]) + j
                                    ] = siop_htoc32(&sc->sc_c, siop_led_off[j]);
                }
        }
        sc->script_free_lo = __arraycount(siop_script);
        sc->script_free_hi = sc->sc_c.ram_size / 4;
        sc->sc_ntargets = 0;

        /* free used and unused lun switches */
        while((lunsw = TAILQ_FIRST(&sc->lunsw_list)) != NULL) {
#ifdef SIOP_DEBUG
                printf("%s: free lunsw at offset %d\n",
                    device_xname(sc->sc_c.sc_dev), lunsw->lunsw_off);
#endif
                TAILQ_REMOVE(&sc->lunsw_list, lunsw, next);
                free(lunsw, M_DEVBUF);
        }
        TAILQ_INIT(&sc->lunsw_list);
        /* restore reselect switch */
        for (i = 0; i < sc->sc_c.sc_chan.chan_ntargets; i++) {
                struct siop_target *target;
                if (sc->sc_c.targets[i] == NULL)
                        continue;
#ifdef SIOP_DEBUG
                printf("%s: restore sw for target %d\n",
                    device_xname(sc->sc_c.sc_dev), i);
#endif
                target = (struct siop_target *)sc->sc_c.targets[i];
                free(target->lunsw, M_DEVBUF);
                target->lunsw = siop_get_lunsw(sc);
                if (target->lunsw == NULL) {
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "can't alloc lunsw for target %d\n", i);
                        break;
                }
                siop_add_reselsw(sc, i);
        }

        /* start script */
        if ((sc->sc_c.features & SF_CHIP_RAM) == 0) {
                bus_dmamap_sync(sc->sc_c.sc_dmat, sc->sc_c.sc_scriptdma, 0,
                    PAGE_SIZE, BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        }
        bus_space_write_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_DSP,
            sc->sc_c.sc_scriptaddr + Ent_reselect);
}

#if 0
#define CALL_SCRIPT(ent) do {                                           \
        printf ("start script DSA 0x%lx DSP 0x%lx\n",                   \
            siop_cmd->cmd_c.dsa,                                        \
            sc->sc_c.sc_scriptaddr + ent);                              \
        bus_space_write_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,               \
            SIOP_DSP, sc->sc_c.sc_scriptaddr + ent);                    \
} while (/* CONSTCOND */0)
#else
#define CALL_SCRIPT(ent) do {                                           \
        bus_space_write_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,               \
            SIOP_DSP, sc->sc_c.sc_scriptaddr + ent);                    \
} while (/* CONSTCOND */0)
#endif

int
siop_intr(void *v)
{
        struct siop_softc *sc = v;
        struct siop_target *siop_target;
        struct siop_cmd *siop_cmd;
        struct siop_lun *siop_lun;
        struct scsipi_xfer *xs;
        int istat, sist, sstat1, dstat = 0; /* XXX: gcc */
        uint32_t irqcode;
        int need_reset = 0;
        int offset, target, lun, tag;
        bus_addr_t dsa;
        struct siop_cbd *cbdp;
        int freetarget = 0;
        int restart = 0;

        istat = bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_ISTAT);
        if ((istat & (ISTAT_INTF | ISTAT_DIP | ISTAT_SIP)) == 0)
                return 0;
        INCSTAT(siop_stat_intr);
        if (istat & ISTAT_INTF) {
                printf("INTRF\n");
                bus_space_write_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_ISTAT, ISTAT_INTF);
        }
        if ((istat &(ISTAT_DIP | ISTAT_SIP | ISTAT_ABRT)) ==
            (ISTAT_DIP | ISTAT_ABRT)) {
                /* clear abort */
                bus_space_write_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_ISTAT, 0);
        }
        /* use DSA to find the current siop_cmd */
        siop_cmd = NULL;
        dsa = bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_DSA);
        TAILQ_FOREACH(cbdp, &sc->cmds, next) {
                if (dsa >= cbdp->xferdma->dm_segs[0].ds_addr &&
                    dsa < cbdp->xferdma->dm_segs[0].ds_addr + PAGE_SIZE) {
                        dsa -= cbdp->xferdma->dm_segs[0].ds_addr;
                        siop_cmd = &cbdp->cmds[dsa / sizeof(struct siop_xfer)];
                        siop_table_sync(siop_cmd,
                            BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
                        break;
                }
        }
        if (siop_cmd) {
                xs = siop_cmd->cmd_c.xs;
                siop_target = (struct siop_target *)siop_cmd->cmd_c.siop_target;
                target = siop_cmd->cmd_c.xs->xs_periph->periph_target;
                lun = siop_cmd->cmd_c.xs->xs_periph->periph_lun;
                tag = siop_cmd->cmd_c.tag;
                siop_lun = siop_target->siop_lun[lun];
#ifdef DIAGNOSTIC
                if (siop_cmd->cmd_c.status != CMDST_ACTIVE) {
                        printf("siop_cmd (lun %d) for DSA 0x%x "
                            "not active (%d)\n", lun, (u_int)dsa,
                            siop_cmd->cmd_c.status);
                        xs = NULL;
                        siop_target = NULL;
                        target = -1;
                        lun = -1;
                        tag = -1;
                        siop_lun = NULL;
                        siop_cmd = NULL;
                } else if (siop_lun->siop_tag[tag].active != siop_cmd) {
                        printf("siop_cmd (lun %d tag %d) not in siop_lun "
                            "active (%p != %p)\n", lun, tag, siop_cmd,
                            siop_lun->siop_tag[tag].active);
                }
#endif
        } else {
                xs = NULL;
                siop_target = NULL;
                target = -1;
                lun = -1;
                tag = -1;
                siop_lun = NULL;
        }
        if (istat & ISTAT_DIP) {
                dstat = bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_DSTAT);
                if (dstat & DSTAT_ABRT) {
                        /* was probably generated by a bus reset IOCTL */
                        if ((dstat & DSTAT_DFE) == 0)
                                siop_clearfifo(&sc->sc_c);
                        goto reset;
                }
                if (dstat & DSTAT_SSI) {
                        printf("single step dsp 0x%08x dsa 0x08%x\n",
                            (int)(bus_space_read_4(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_DSP) -
                            sc->sc_c.sc_scriptaddr),
                            bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                                SIOP_DSA));
                        if ((dstat & ~(DSTAT_DFE | DSTAT_SSI)) == 0 &&
                            (istat & ISTAT_SIP) == 0) {
                                bus_space_write_1(sc->sc_c.sc_rt,
                                    sc->sc_c.sc_rh, SIOP_DCNTL,
                                    bus_space_read_1(sc->sc_c.sc_rt,
                                    sc->sc_c.sc_rh, SIOP_DCNTL) | DCNTL_STD);
                        }
                        return 1;
                }

                if (dstat & ~(DSTAT_SIR | DSTAT_DFE | DSTAT_SSI)) {
                printf("DMA IRQ:");
                if (dstat & DSTAT_IID)
                        printf(" Illegal instruction");
                if (dstat & DSTAT_BF)
                        printf(" bus fault");
                if (dstat & DSTAT_MDPE)
                        printf(" parity");
                if (dstat & DSTAT_DFE)
                        printf(" DMA fifo empty");
                else
                        siop_clearfifo(&sc->sc_c);
                printf(", DSP=0x%x DSA=0x%x: ",
                    (int)(bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                        SIOP_DSP) - sc->sc_c.sc_scriptaddr),
                    bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_DSA));
                if (siop_cmd)
                        printf("last msg_in=0x%x status=0x%x\n",
                            siop_cmd->cmd_tables->msg_in[0],
                            siop_ctoh32(&sc->sc_c,
                                siop_cmd->cmd_tables->status));
                else
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "current DSA invalid\n");
                need_reset = 1;
                }
        }
        if (istat & ISTAT_SIP) {
                if (istat & ISTAT_DIP)
                        delay(10);
                /*
                 * Can't read sist0 & sist1 independently, or we have to
                 * insert delay
                 */
                sist = bus_space_read_2(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_SIST0);
                sstat1 = bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_SSTAT1);
#ifdef SIOP_DEBUG_INTR
                printf("scsi interrupt, sist=0x%x sstat1=0x%x "
                    "DSA=0x%x DSP=0x%lx\n", sist,
                    bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                        SIOP_SSTAT1),
                    bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_DSA),
                    (u_long)(bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                        SIOP_DSP) -
                    sc->sc_c.sc_scriptaddr));
#endif
                if (sist & SIST0_RST) {
                        siop_handle_reset(sc);
                        /* no table to flush here */
                        return 1;
                }
                if (sist & SIST0_SGE) {
                        if (siop_cmd)
                                scsipi_printaddr(xs->xs_periph);
                        else
                                printf("%s:", device_xname(sc->sc_c.sc_dev));
                        printf("scsi gross error\n");
                        goto reset;
                }
                if ((sist & SIST0_MA) && need_reset == 0) {
                        if (siop_cmd) {
                                int scratcha0;
                                dstat = bus_space_read_1(sc->sc_c.sc_rt,
                                    sc->sc_c.sc_rh, SIOP_DSTAT);
                                /*
                                 * first restore DSA, in case we were in a S/G
                                 * operation.
                                 */
                                bus_space_write_4(sc->sc_c.sc_rt,
                                    sc->sc_c.sc_rh,
                                    SIOP_DSA, siop_cmd->cmd_c.dsa);
                                scratcha0 = bus_space_read_1(sc->sc_c.sc_rt,
                                    sc->sc_c.sc_rh, SIOP_SCRATCHA);
                                switch (sstat1 & SSTAT1_PHASE_MASK) {
                                case SSTAT1_PHASE_STATUS:
                                /*
                                 * previous phase may be aborted for any reason
                                 * ( for example, the target has less data to
                                 * transfer than requested). Compute resid and
                                 * just go to status, the command should
                                 * terminate.
                                 */
                                        INCSTAT(siop_stat_intr_shortxfer);
                                        if (scratcha0 & A_flag_data)
                                                siop_ma(&siop_cmd->cmd_c);
                                        else if ((dstat & DSTAT_DFE) == 0)
                                                siop_clearfifo(&sc->sc_c);
                                        CALL_SCRIPT(Ent_status);
                                        return 1;
                                case SSTAT1_PHASE_MSGIN:
                                /*
                                 * target may be ready to disconnect
                                 * Compute resid which would be used later
                                 * if a save data pointer is needed.
                                 */
                                        INCSTAT(siop_stat_intr_xferdisc);
                                        if (scratcha0 & A_flag_data)
                                                siop_ma(&siop_cmd->cmd_c);
                                        else if ((dstat & DSTAT_DFE) == 0)
                                                siop_clearfifo(&sc->sc_c);
                                        bus_space_write_1(sc->sc_c.sc_rt,
                                            sc->sc_c.sc_rh, SIOP_SCRATCHA,
                                            scratcha0 & ~A_flag_data);
                                        CALL_SCRIPT(Ent_msgin);
                                        return 1;
                                }
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "unexpected phase mismatch %d\n",
                                    sstat1 & SSTAT1_PHASE_MASK);
                        } else {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "phase mismatch without command\n");
                        }
                        need_reset = 1;
                }
                if (sist & SIST0_PAR) {
                        /* parity error, reset */
                        if (siop_cmd)
                                scsipi_printaddr(xs->xs_periph);
                        else
                                printf("%s:", device_xname(sc->sc_c.sc_dev));
                        printf("parity error\n");
                        goto reset;
                }
                if ((sist & (SIST1_STO << 8)) && need_reset == 0) {
                        /* selection time out, assume there's no device here */
                        if (siop_cmd) {
                                siop_cmd->cmd_c.status = CMDST_DONE;
                                xs->error = XS_SELTIMEOUT;
                                freetarget = 1;
                                goto end;
                        } else {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "selection timeout without "
                                    "command\n");
                                need_reset = 1;
                        }
                }
                if (sist & SIST0_UDC) {
                        /*
                         * unexpected disconnect. Usually the target signals
                         * a fatal condition this way. Attempt to get sense.
                         */
                         if (siop_cmd) {
                                siop_cmd->cmd_tables->status =
                                    siop_htoc32(&sc->sc_c, SCSI_CHECK);
                                goto end;
                        }
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "unexpected disconnect without "
                            "command\n");
                        goto reset;
                }
                if (sist & (SIST1_SBMC << 8)) {
                        /* SCSI bus mode change */
                        if (siop_modechange(&sc->sc_c) == 0 || need_reset == 1)
                                goto reset;
                        if ((istat & ISTAT_DIP) && (dstat & DSTAT_SIR)) {
                                /*
                                 * we have a script interrupt, it will
                                 * restart the script.
                                 */
                                goto scintr;
                        }
                        /*
                         * else we have to restart it ourselves, at the
                         * interrupted instruction.
                         */
                        bus_space_write_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                            SIOP_DSP,
                            bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                            SIOP_DSP) - 8);
                        return 1;
                }
                /* Else it's an unhandled exception (for now). */
                aprint_error_dev(sc->sc_c.sc_dev,
                    "unhandled scsi interrupt, sist=0x%x sstat1=0x%x "
                    "DSA=0x%x DSP=0x%x\n", sist,
                    bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                        SIOP_SSTAT1),
                    bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh, SIOP_DSA),
                    (int)(bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                        SIOP_DSP) - sc->sc_c.sc_scriptaddr));
                if (siop_cmd) {
                        siop_cmd->cmd_c.status = CMDST_DONE;
                        xs->error = XS_SELTIMEOUT;
                        goto end;
                }
                need_reset = 1;
        }
        if (need_reset) {
reset:
                /* fatal error, reset the bus */
                siop_resetbus(&sc->sc_c);
                /* no table to flush here */
                return 1;
        }

scintr:
        if ((istat & ISTAT_DIP) && (dstat & DSTAT_SIR)) { /* script interrupt */
                irqcode = bus_space_read_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                    SIOP_DSPS);
#ifdef SIOP_DEBUG_INTR
                printf("script interrupt 0x%x\n", irqcode);
#endif
                /*
                 * no command, or an inactive command is only valid for a
                 * reselect interrupt
                 */
                if ((irqcode & 0x80) == 0) {
                        if (siop_cmd == NULL) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "script interrupt (0x%x) with "
                                    "invalid DSA !!!\n",
                                    irqcode);
                                goto reset;
                        }
                        if (siop_cmd->cmd_c.status != CMDST_ACTIVE) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                     "command with invalid status "
                                    "(IRQ code 0x%x current status %d) !\n",
                                    irqcode, siop_cmd->cmd_c.status);
                                xs = NULL;
                        }
                }
                switch(irqcode) {
                case A_int_err:
                        printf("error, DSP=0x%x\n",
                            (int)(bus_space_read_4(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_DSP) -
                            sc->sc_c.sc_scriptaddr));
                        if (xs) {
                                xs->error = XS_SELTIMEOUT;
                                goto end;
                        } else {
                                goto reset;
                        }
                case A_int_reseltarg:
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "reselect with invalid target\n");
                        goto reset;
                case A_int_resellun:
                        INCSTAT(siop_stat_intr_lunresel);
                        target = bus_space_read_1(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_SCRATCHA) & 0xf;
                        lun = bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                            SIOP_SCRATCHA + 1);
                        tag = bus_space_read_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                            SIOP_SCRATCHA + 2);
                        siop_target =
                            (struct siop_target *)sc->sc_c.targets[target];
                        if (siop_target == NULL) {
                                printf("%s: reselect with invalid target %d\n",
                                    device_xname(sc->sc_c.sc_dev), target);
                                goto reset;
                        }
                        siop_lun = siop_target->siop_lun[lun];
                        if (siop_lun == NULL) {
                                printf("%s: target %d reselect with invalid "
                                    "lun %d\n", device_xname(sc->sc_c.sc_dev),
                                    target, lun);
                                goto reset;
                        }
                        if (siop_lun->siop_tag[tag].active == NULL) {
                                printf("%s: target %d lun %d tag %d reselect "
                                    "without command\n",
                                    device_xname(sc->sc_c.sc_dev),
                                    target, lun, tag);
                                goto reset;
                        }
                        siop_cmd = siop_lun->siop_tag[tag].active;
                        bus_space_write_4(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
                            SIOP_DSP, siop_cmd->cmd_c.dsa +
                            sizeof(struct siop_common_xfer) +
                            Ent_ldsa_reload_dsa);
                        siop_table_sync(siop_cmd, BUS_DMASYNC_PREWRITE);
                        return 1;
                case A_int_reseltag:
                        printf("%s: reselect with invalid tag\n",
                            device_xname(sc->sc_c.sc_dev));
                        goto reset;
                case A_int_msgin:
                {
                        int msgin = bus_space_read_1(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_SFBR);

                        if (msgin == MSG_MESSAGE_REJECT) {
                                int msg, extmsg;
                                if (siop_cmd->cmd_tables->msg_out[0] & 0x80) {
                                        /*
                                         * message was part of a identify +
                                         * something else. Identify shouldn't
                                         * have been rejected.
                                         */
                                        msg =
                                            siop_cmd->cmd_tables->msg_out[1];
                                        extmsg =
                                            siop_cmd->cmd_tables->msg_out[3];
                                } else {
                                        msg = siop_cmd->cmd_tables->msg_out[0];
                                        extmsg =
                                            siop_cmd->cmd_tables->msg_out[2];
                                }
                                if (msg == MSG_MESSAGE_REJECT) {
                                        /* MSG_REJECT  for a MSG_REJECT  !*/
                                        if (xs)
                                                scsipi_printaddr(xs->xs_periph);
                                        else
                                                printf("%s: ", device_xname(
                                                    sc->sc_c.sc_dev));
                                        printf("our reject message was "
                                            "rejected\n");
                                        goto reset;
                                }
                                if (msg == MSG_EXTENDED &&
                                    extmsg == MSG_EXT_WDTR) {
                                        /* WDTR rejected, initiate sync */
                                        if ((siop_target->target_c.flags &
                                           TARF_SYNC) == 0) {
                                                siop_target->target_c.status =
                                                    TARST_OK;
                                                siop_update_xfer_mode(&sc->sc_c,
                                                    target);
                                                /* no table to flush here */
                                                CALL_SCRIPT(Ent_msgin_ack);
                                                return 1;
                                        }
                                        siop_target->target_c.status =
                                            TARST_SYNC_NEG;
                                        siop_sdtr_msg(&siop_cmd->cmd_c, 0,
                                            sc->sc_c.st_minsync,
                                            sc->sc_c.maxoff);
                                        siop_table_sync(siop_cmd,
                                            BUS_DMASYNC_PREREAD |
                                            BUS_DMASYNC_PREWRITE);
                                        CALL_SCRIPT(Ent_send_msgout);
                                        return 1;
                                } else if (msg == MSG_EXTENDED &&
                                    extmsg == MSG_EXT_SDTR) {
                                        /* sync rejected */
                                        siop_target->target_c.offset = 0;
                                        siop_target->target_c.period = 0;
                                        siop_target->target_c.status = TARST_OK;
                                        siop_update_xfer_mode(&sc->sc_c,
                                            target);
                                        /* no table to flush here */
                                        CALL_SCRIPT(Ent_msgin_ack);
                                        return 1;
                                } else if (msg == MSG_SIMPLE_Q_TAG ||
                                    msg == MSG_HEAD_OF_Q_TAG ||
                                    msg == MSG_ORDERED_Q_TAG) {
                                        if (siop_handle_qtag_reject(
                                            siop_cmd) == -1)
                                                goto reset;
                                        CALL_SCRIPT(Ent_msgin_ack);
                                        return 1;
                                }
                                if (xs)
                                        scsipi_printaddr(xs->xs_periph);
                                else
                                        printf("%s: ",
                                            device_xname(sc->sc_c.sc_dev));
                                if (msg == MSG_EXTENDED) {
                                        printf("scsi message reject, extended "
                                            "message sent was 0x%x\n", extmsg);
                                } else {
                                        printf("scsi message reject, message "
                                            "sent was 0x%x\n", msg);
                                }
                                /* no table to flush here */
                                CALL_SCRIPT(Ent_msgin_ack);
                                return 1;
                        }
                        if (msgin == MSG_IGN_WIDE_RESIDUE) {
                        /* use the extmsgdata table to get the second byte */
                                siop_cmd->cmd_tables->t_extmsgdata.count =
                                    siop_htoc32(&sc->sc_c, 1);
                                siop_table_sync(siop_cmd,
                                    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                                CALL_SCRIPT(Ent_get_extmsgdata);
                                return 1;
                        }
                        if (xs)
                                scsipi_printaddr(xs->xs_periph);
                        else
                                printf("%s: ", device_xname(sc->sc_c.sc_dev));
                        printf("unhandled message 0x%x\n",
                            siop_cmd->cmd_tables->msg_in[0]);
                        siop_cmd->cmd_tables->msg_out[0] = MSG_MESSAGE_REJECT;
                        siop_cmd->cmd_tables->t_msgout.count =
                                siop_htoc32(&sc->sc_c, 1);
                        siop_table_sync(siop_cmd,
                            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                        CALL_SCRIPT(Ent_send_msgout);
                        return 1;
                }
                case A_int_extmsgin:
#ifdef SIOP_DEBUG_INTR
                        printf("extended message: msg 0x%x len %d\n",
                            siop_cmd->cmd_tables->msg_in[2],
                            siop_cmd->cmd_tables->msg_in[1]);
#endif
                        if (siop_cmd->cmd_tables->msg_in[1] >
                            sizeof(siop_cmd->cmd_tables->msg_in) - 2)
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "extended message too big (%d)\n",
                                    siop_cmd->cmd_tables->msg_in[1]);
                        siop_cmd->cmd_tables->t_extmsgdata.count =
                            siop_htoc32(&sc->sc_c,
                                siop_cmd->cmd_tables->msg_in[1] - 1);
                        siop_table_sync(siop_cmd,
                            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                        CALL_SCRIPT(Ent_get_extmsgdata);
                        return 1;
                case A_int_extmsgdata:
#ifdef SIOP_DEBUG_INTR
                        {
                        int i;
                        printf("extended message: 0x%x, data:",
                            siop_cmd->cmd_tables->msg_in[2]);
                        for (i = 3; i < 2 + siop_cmd->cmd_tables->msg_in[1];
                            i++)
                                printf(" 0x%x",
                                    siop_cmd->cmd_tables->msg_in[i]);
                        printf("\n");
                        }
#endif
                        if (siop_cmd->cmd_tables->msg_in[0] ==
                            MSG_IGN_WIDE_RESIDUE) {
                        /* we got the second byte of MSG_IGN_WIDE_RESIDUE */
                                if (siop_cmd->cmd_tables->msg_in[3] != 1)
                                        printf("MSG_IGN_WIDE_RESIDUE: "
                                            "bad len %d\n",
                                            siop_cmd->cmd_tables->msg_in[3]);
                                switch (siop_iwr(&siop_cmd->cmd_c)) {
                                case SIOP_NEG_MSGOUT:
                                        siop_table_sync(siop_cmd,
                                            BUS_DMASYNC_PREREAD |
                                            BUS_DMASYNC_PREWRITE);
                                        CALL_SCRIPT(Ent_send_msgout);
                                        return(1);
                                case SIOP_NEG_ACK:
                                        CALL_SCRIPT(Ent_msgin_ack);
                                        return(1);
                                default:
                                        panic("invalid retval from "
                                            "siop_iwr()");
                                }
                                return(1);
                        }
                        if (siop_cmd->cmd_tables->msg_in[2] == MSG_EXT_WDTR) {
                                switch (siop_wdtr_neg(&siop_cmd->cmd_c)) {
                                case SIOP_NEG_MSGOUT:
                                        siop_update_scntl3(sc,
                                            siop_cmd->cmd_c.siop_target);
                                        siop_table_sync(siop_cmd,
                                            BUS_DMASYNC_PREREAD |
                                            BUS_DMASYNC_PREWRITE);
                                        CALL_SCRIPT(Ent_send_msgout);
                                        return(1);
                                case SIOP_NEG_ACK:
                                        siop_update_scntl3(sc,
                                            siop_cmd->cmd_c.siop_target);
                                        CALL_SCRIPT(Ent_msgin_ack);
                                        return(1);
                                default:
                                        panic("invalid retval from "
                                            "siop_wdtr_neg()");
                                }
                                return(1);
                        }
                        if (siop_cmd->cmd_tables->msg_in[2] == MSG_EXT_SDTR) {
                                switch (siop_sdtr_neg(&siop_cmd->cmd_c)) {
                                case SIOP_NEG_MSGOUT:
                                        siop_update_scntl3(sc,
                                            siop_cmd->cmd_c.siop_target);
                                        siop_table_sync(siop_cmd,
                                            BUS_DMASYNC_PREREAD |
                                            BUS_DMASYNC_PREWRITE);
                                        CALL_SCRIPT(Ent_send_msgout);
                                        return(1);
                                case SIOP_NEG_ACK:
                                        siop_update_scntl3(sc,
                                            siop_cmd->cmd_c.siop_target);
                                        CALL_SCRIPT(Ent_msgin_ack);
                                        return(1);
                                default:
                                        panic("invalid retval from "
                                            "siop_sdtr_neg()");
                                }
                                return(1);
                        }
                        /* send a message reject */
                        siop_cmd->cmd_tables->msg_out[0] = MSG_MESSAGE_REJECT;
                        siop_cmd->cmd_tables->t_msgout.count =
                            siop_htoc32(&sc->sc_c, 1);
                        siop_table_sync(siop_cmd,
                            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                        CALL_SCRIPT(Ent_send_msgout);
                        return 1;
                case A_int_disc:
                        INCSTAT(siop_stat_intr_sdp);
                        offset = bus_space_read_1(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_SCRATCHA + 1);
#ifdef SIOP_DEBUG_DR
                        printf("disconnect offset %d\n", offset);
#endif
                        siop_sdp(&siop_cmd->cmd_c, offset);
                        /* we start again with no offset */
                        siop_cmd->saved_offset = SIOP_NOOFFSET;
                        siop_table_sync(siop_cmd,
                            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                        CALL_SCRIPT(Ent_script_sched);
                        return 1;
                case A_int_saveoffset:
                        INCSTAT(siop_stat_intr_saveoffset);
                        offset = bus_space_read_1(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_SCRATCHA + 1);
#ifdef SIOP_DEBUG_DR
                        printf("saveoffset offset %d\n", offset);
#endif
                        siop_cmd->saved_offset = offset;
                        CALL_SCRIPT(Ent_script_sched);
                        return 1;
                case A_int_resfail:
                        printf("reselect failed\n");
                        CALL_SCRIPT(Ent_script_sched);
                        return  1;
                case A_int_done:
                        if (xs == NULL) {
                                printf("%s: done without command, DSA=0x%lx\n",
                                    device_xname(sc->sc_c.sc_dev),
                                    (u_long)siop_cmd->cmd_c.dsa);
                                siop_cmd->cmd_c.status = CMDST_FREE;
                                CALL_SCRIPT(Ent_script_sched);
                                return 1;
                        }
#ifdef SIOP_DEBUG_INTR
                        printf("done, DSA=0x%lx target id 0x%x last msg "
                            "in=0x%x status=0x%x\n",
                            (u_long)siop_cmd->cmd_c.dsa,
                            siop_ctoh32(&sc->sc_c, siop_cmd->cmd_tables->id),
                            siop_cmd->cmd_tables->msg_in[0],
                            siop_ctoh32(&sc->sc_c,
                                siop_cmd->cmd_tables->status));
#endif
                        INCSTAT(siop_stat_intr_done);
                        /* update resid.  */
                        offset = bus_space_read_1(sc->sc_c.sc_rt,
                            sc->sc_c.sc_rh, SIOP_SCRATCHA + 1);
                        /*
                         * if we got a disconnect between the last data phase
                         * and the status phase, offset will be 0. In this
                         * case, siop_cmd->saved_offset will have the proper
                         * value if it got updated by the controller
                         */
                        if (offset == 0 &&
                            siop_cmd->saved_offset != SIOP_NOOFFSET)
                                offset = siop_cmd->saved_offset;
                        siop_update_resid(&siop_cmd->cmd_c, offset);
                        siop_cmd->cmd_c.status = CMDST_DONE;
                        goto end;
                default:
                        printf("unknown irqcode %x\n", irqcode);
                        if (xs) {
                                xs->error = XS_SELTIMEOUT;
                                goto end;
                        }
                        goto reset;
                }
                return 1;
        }
        /*
         * We just shouldn't get there, but on some KVM virtual hosts,
         * we do - see PR 48277.
         */
        printf("siop_intr: I shouldn't be there !\n");
        return 1;

end:
        /*
         * restart the script now if command completed properly
         * Otherwise wait for siop_scsicmd_end(), we may need to cleanup the
         * queue
         */
        xs->status = siop_ctoh32(&sc->sc_c, siop_cmd->cmd_tables->status);
        if (xs->status == SCSI_OK)
                CALL_SCRIPT(Ent_script_sched);
        else
                restart = 1;
        siop_lun->siop_tag[tag].active = NULL;
        siop_scsicmd_end(siop_cmd);
        if (freetarget && siop_target->target_c.status == TARST_PROBING)
                siop_del_dev(sc, target, lun);
        if (restart)
                CALL_SCRIPT(Ent_script_sched);
        if (sc->sc_flags & SCF_CHAN_NOSLOT) {
                /* a command terminated, so we have free slots now */
                sc->sc_flags &= ~SCF_CHAN_NOSLOT;
                scsipi_channel_thaw(&sc->sc_c.sc_chan, 1);
        }

        return 1;
}

void
siop_scsicmd_end(struct siop_cmd *siop_cmd)
{
        struct scsipi_xfer *xs = siop_cmd->cmd_c.xs;
        struct siop_softc *sc = (struct siop_softc *)siop_cmd->cmd_c.siop_sc;

        switch(xs->status) {
        case SCSI_OK:
                xs->error = XS_NOERROR;
                break;
        case SCSI_BUSY:
                xs->error = XS_BUSY;
                break;
        case SCSI_CHECK:
                xs->error = XS_BUSY;
                /* remove commands in the queue and scheduler */
                siop_unqueue(sc, xs->xs_periph->periph_target,
                    xs->xs_periph->periph_lun);
                break;
        case SCSI_QUEUE_FULL:
                INCSTAT(siop_stat_intr_qfull);
#ifdef SIOP_DEBUG
                printf("%s:%d:%d: queue full (tag %d)\n",
                    device_xname(sc->sc_c.sc_dev),
                    xs->xs_periph->periph_target,
                    xs->xs_periph->periph_lun, siop_cmd->cmd_c.tag);
#endif
                xs->error = XS_BUSY;
                break;
        case SCSI_SIOP_NOCHECK:
                /*
                 * don't check status, xs->error is already valid
                 */
                break;
        case SCSI_SIOP_NOSTATUS:
                /*
                 * the status byte was not updated, cmd was
                 * aborted
                 */
                xs->error = XS_SELTIMEOUT;
                break;
        default:
                scsipi_printaddr(xs->xs_periph);
                printf("invalid status code %d\n", xs->status);
                xs->error = XS_DRIVER_STUFFUP;
        }
        if (xs->xs_control & (XS_CTL_DATA_IN | XS_CTL_DATA_OUT)) {
                bus_dmamap_sync(sc->sc_c.sc_dmat, siop_cmd->cmd_c.dmamap_data,
                    0, siop_cmd->cmd_c.dmamap_data->dm_mapsize,
                    (xs->xs_control & XS_CTL_DATA_IN) ?
                    BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
                bus_dmamap_unload(sc->sc_c.sc_dmat,
                    siop_cmd->cmd_c.dmamap_data);
        }
        bus_dmamap_unload(sc->sc_c.sc_dmat, siop_cmd->cmd_c.dmamap_cmd);
        if ((xs->xs_control & XS_CTL_POLL) == 0)
                callout_stop(&xs->xs_callout);
        siop_cmd->cmd_c.status = CMDST_FREE;
        TAILQ_INSERT_TAIL(&sc->free_list, siop_cmd, next);
#if 0
        if (xs->resid != 0)
                printf("resid %d datalen %d\n", xs->resid, xs->datalen);
#endif
        scsipi_done(xs);
}

void
siop_unqueue(struct siop_softc *sc, int target, int lun)
{
        int slot, tag;
        struct siop_cmd *siop_cmd;
        struct siop_lun *siop_lun =
            ((struct siop_target *)sc->sc_c.targets[target])->siop_lun[lun];

        /* first make sure to read valid data */
        siop_script_sync(sc, BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);

        for (tag = 1; tag < SIOP_NTAG; tag++) {
                /* look for commands in the scheduler, not yet started */
                if (siop_lun->siop_tag[tag].active == NULL)
                        continue;
                siop_cmd = siop_lun->siop_tag[tag].active;
                for (slot = 0; slot <= sc->sc_currschedslot; slot++) {
                        if (siop_script_read(sc,
                            (Ent_script_sched_slot0 / 4) + slot * 2 + 1) ==
                            siop_cmd->cmd_c.dsa +
                            sizeof(struct siop_common_xfer) +
                            Ent_ldsa_select)
                                break;
                }
                if (slot >  sc->sc_currschedslot)
                        continue; /* didn't find it */
                if (siop_script_read(sc,
                    (Ent_script_sched_slot0 / 4) + slot * 2) == 0x80000000)
                        continue; /* already started */
                /* clear the slot */
                siop_script_write(sc, (Ent_script_sched_slot0 / 4) + slot * 2,
                    0x80000000);
                /* ask to requeue */
                siop_cmd->cmd_c.xs->error = XS_REQUEUE;
                siop_cmd->cmd_c.xs->status = SCSI_SIOP_NOCHECK;
                siop_lun->siop_tag[tag].active = NULL;
                siop_scsicmd_end(siop_cmd);
        }
        /* update sc_currschedslot */
        sc->sc_currschedslot = 0;
        for (slot = SIOP_NSLOTS - 1; slot >= 0; slot--) {
                if (siop_script_read(sc,
                    (Ent_script_sched_slot0 / 4) + slot * 2) != 0x80000000)
                        sc->sc_currschedslot = slot;
        }
}

/*
 * handle a rejected queue tag message: the command will run untagged,
 * has to adjust the reselect script.
 */
int
siop_handle_qtag_reject(struct siop_cmd *siop_cmd)
{
        struct siop_softc *sc = (struct siop_softc *)siop_cmd->cmd_c.siop_sc;
        int target = siop_cmd->cmd_c.xs->xs_periph->periph_target;
        int lun = siop_cmd->cmd_c.xs->xs_periph->periph_lun;
        int tag = siop_cmd->cmd_tables->msg_out[2];
        struct siop_lun *siop_lun =
            ((struct siop_target*)sc->sc_c.targets[target])->siop_lun[lun];

#ifdef SIOP_DEBUG
        printf("%s:%d:%d: tag message %d (%d) rejected (status %d)\n",
            device_xname(sc->sc_c.sc_dev), target, lun, tag,
            siop_cmd->cmd_c.tag,
            siop_cmd->cmd_c.status);
#endif

        if (siop_lun->siop_tag[0].active != NULL) {
                printf("%s: untagged command already running for target %d "
                    "lun %d (status %d)\n", device_xname(sc->sc_c.sc_dev),
                    target, lun, siop_lun->siop_tag[0].active->cmd_c.status);
                return -1;
        }
        /* clear tag slot */
        siop_lun->siop_tag[tag].active = NULL;
        /* add command to non-tagged slot */
        siop_lun->siop_tag[0].active = siop_cmd;
        siop_cmd->cmd_c.tag = 0;
        /* adjust reselect script if there is one */
        if (siop_lun->siop_tag[0].reseloff > 0) {
                siop_script_write(sc,
                    siop_lun->siop_tag[0].reseloff + 1,
                    siop_cmd->cmd_c.dsa + sizeof(struct siop_common_xfer) +
                    Ent_ldsa_reload_dsa);
                siop_table_sync(siop_cmd, BUS_DMASYNC_PREWRITE);
        }
        return 0;
}

/*
 * handle a bus reset: reset chip, unqueue all active commands, free all
 * target struct and report lossage to upper layer.
 * As the upper layer may requeue immediately we have to first store
 * all active commands in a temporary queue.
 */
void
siop_handle_reset(struct siop_softc *sc)
{
        struct siop_cmd *siop_cmd;
        struct siop_lun *siop_lun;
        int target, lun, tag;

        /*
         * scsi bus reset. reset the chip and restart
         * the queue. Need to clean up all active commands
         */
        printf("%s: scsi bus reset\n", device_xname(sc->sc_c.sc_dev));
        /* stop, reset and restart the chip */
        siop_reset(sc);
        if (sc->sc_flags & SCF_CHAN_NOSLOT) {
                /* chip has been reset, all slots are free now */
                sc->sc_flags &= ~SCF_CHAN_NOSLOT;
                scsipi_channel_thaw(&sc->sc_c.sc_chan, 1);
        }
        /*
         * Process all commands: first commands being executed
         */
        for (target = 0; target < sc->sc_c.sc_chan.chan_ntargets;
            target++) {
                if (sc->sc_c.targets[target] == NULL)
                        continue;
                for (lun = 0; lun < 8; lun++) {
                        struct siop_target *siop_target =
                            (struct siop_target *)sc->sc_c.targets[target];
                        siop_lun = siop_target->siop_lun[lun];
                        if (siop_lun == NULL)
                                continue;
                        for (tag = 0; tag <
                            ((sc->sc_c.targets[target]->flags & TARF_TAG) ?
                            SIOP_NTAG : 1);
                            tag++) {
                                siop_cmd = siop_lun->siop_tag[tag].active;
                                if (siop_cmd == NULL)
                                        continue;
                                scsipi_printaddr(siop_cmd->cmd_c.xs->xs_periph);
                                printf("command with tag id %d reset\n", tag);
                                siop_cmd->cmd_c.xs->error =
                                    (siop_cmd->cmd_c.flags & CMDFL_TIMEOUT) ?
                                    XS_TIMEOUT : XS_RESET;
                                siop_cmd->cmd_c.xs->status = SCSI_SIOP_NOCHECK;
                                siop_lun->siop_tag[tag].active = NULL;
                                siop_cmd->cmd_c.status = CMDST_DONE;
                                siop_scsicmd_end(siop_cmd);
                        }
                }
                sc->sc_c.targets[target]->status = TARST_ASYNC;
                sc->sc_c.targets[target]->flags &= ~TARF_ISWIDE;
                sc->sc_c.targets[target]->period =
                    sc->sc_c.targets[target]->offset = 0;
                siop_update_xfer_mode(&sc->sc_c, target);
        }

        scsipi_async_event(&sc->sc_c.sc_chan, ASYNC_EVENT_RESET, NULL);
}

void
siop_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
    void *arg)
{
        struct scsipi_xfer *xs;
        struct scsipi_periph *periph;
        struct siop_softc *sc = device_private(chan->chan_adapter->adapt_dev);
        struct siop_cmd *siop_cmd;
        struct siop_target *siop_target;
        int s, error, i;
        int target;
        int lun;

        switch (req) {
        case ADAPTER_REQ_RUN_XFER:
                xs = arg;
                periph = xs->xs_periph;
                target = periph->periph_target;
                lun = periph->periph_lun;

                s = splbio();
#ifdef SIOP_DEBUG_SCHED
                printf("starting cmd for %d:%d\n", target, lun);
#endif
                siop_cmd = TAILQ_FIRST(&sc->free_list);
                if (siop_cmd == NULL) {
                        xs->error = XS_RESOURCE_SHORTAGE;
                        scsipi_done(xs);
                        splx(s);
                        return;
                }
                TAILQ_REMOVE(&sc->free_list, siop_cmd, next);
#ifdef DIAGNOSTIC
                if (siop_cmd->cmd_c.status != CMDST_FREE)
                        panic("siop_scsicmd: new cmd not free");
#endif
                siop_target = (struct siop_target *)sc->sc_c.targets[target];
                if (siop_target == NULL) {
#ifdef SIOP_DEBUG
                        printf("%s: alloc siop_target for target %d\n",
                            device_xname(sc->sc_c.sc_dev), target);
#endif
                        sc->sc_c.targets[target] =
                            malloc(sizeof(struct siop_target),
                                M_DEVBUF, M_NOWAIT|M_ZERO);
                        if (sc->sc_c.targets[target] == NULL) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "can't malloc memory for "
                                    "target %d\n", target);
                                xs->error = XS_RESOURCE_SHORTAGE;
                                scsipi_done(xs);
                                TAILQ_INSERT_TAIL(&sc->free_list,
                                    siop_cmd, next);
                                splx(s);
                                return;
                        }
                        siop_target =
                            (struct siop_target *)sc->sc_c.targets[target];
                        siop_target->target_c.status = TARST_PROBING;
                        siop_target->target_c.flags = 0;
                        siop_target->target_c.id =
                            sc->sc_c.clock_div << 24; /* scntl3 */
                        siop_target->target_c.id |=  target << 16; /* id */
                        /* siop_target->target_c.id |= 0x0 << 8; scxfer is 0 */

                        /* get a lun switch script */
                        siop_target->lunsw = siop_get_lunsw(sc);
                        if (siop_target->lunsw == NULL) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "can't alloc lunsw for target %d\n",
                                    target);
                                xs->error = XS_RESOURCE_SHORTAGE;
                                scsipi_done(xs);
                                TAILQ_INSERT_TAIL(&sc->free_list,
                                    siop_cmd, next);
                                splx(s);
                                return;
                        }
                        for (i=0; i < 8; i++)
                                siop_target->siop_lun[i] = NULL;
                        siop_add_reselsw(sc, target);
                }
                if (siop_target->siop_lun[lun] == NULL) {
                        siop_target->siop_lun[lun] =
                            malloc(sizeof(struct siop_lun), M_DEVBUF,
                            M_NOWAIT|M_ZERO);
                        if (siop_target->siop_lun[lun] == NULL) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "can't alloc siop_lun for "
                                    "target %d lun %d\n",
                                    target, lun);
                                xs->error = XS_RESOURCE_SHORTAGE;
                                scsipi_done(xs);
                                TAILQ_INSERT_TAIL(&sc->free_list,
                                    siop_cmd, next);
                                splx(s);
                                return;
                        }
                }
                siop_cmd->cmd_c.siop_target = sc->sc_c.targets[target];
                siop_cmd->cmd_c.xs = xs;
                siop_cmd->cmd_c.flags = 0;
                siop_cmd->cmd_c.status = CMDST_READY;

                /* load the DMA maps */
                error = bus_dmamap_load(sc->sc_c.sc_dmat,
                    siop_cmd->cmd_c.dmamap_cmd,
                    xs->cmd, xs->cmdlen, NULL, BUS_DMA_NOWAIT);
                if (error) {
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "unable to load cmd DMA map: %d\n",
                            error);
                        xs->error = (error == EAGAIN) ?
                            XS_RESOURCE_SHORTAGE : XS_DRIVER_STUFFUP;
                        scsipi_done(xs);
                        siop_cmd->cmd_c.status = CMDST_FREE;
                        TAILQ_INSERT_TAIL(&sc->free_list, siop_cmd, next);
                        splx(s);
                        return;
                }
                if (xs->xs_control & (XS_CTL_DATA_IN | XS_CTL_DATA_OUT)) {
                        error = bus_dmamap_load(sc->sc_c.sc_dmat,
                            siop_cmd->cmd_c.dmamap_data, xs->data, xs->datalen,
                            NULL, BUS_DMA_NOWAIT | BUS_DMA_STREAMING |
                            ((xs->xs_control & XS_CTL_DATA_IN) ?
                             BUS_DMA_READ : BUS_DMA_WRITE));
                        if (error) {
                                aprint_error_dev(sc->sc_c.sc_dev,
                                    "unable to load data DMA map: %d\n",
                                    error);
                                xs->error = (error == EAGAIN) ?
                                    XS_RESOURCE_SHORTAGE : XS_DRIVER_STUFFUP;
                                scsipi_done(xs);
                                bus_dmamap_unload(sc->sc_c.sc_dmat,
                                    siop_cmd->cmd_c.dmamap_cmd);
                                siop_cmd->cmd_c.status = CMDST_FREE;
                                TAILQ_INSERT_TAIL(&sc->free_list,
                                    siop_cmd, next);
                                splx(s);
                                return;
                        }
                        bus_dmamap_sync(sc->sc_c.sc_dmat,
                            siop_cmd->cmd_c.dmamap_data, 0,
                            siop_cmd->cmd_c.dmamap_data->dm_mapsize,
                            (xs->xs_control & XS_CTL_DATA_IN) ?
                            BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
                }
                bus_dmamap_sync(sc->sc_c.sc_dmat, siop_cmd->cmd_c.dmamap_cmd, 0,
                    siop_cmd->cmd_c.dmamap_cmd->dm_mapsize,
                    BUS_DMASYNC_PREWRITE);

                if (xs->xs_tag_type) {
                        /* use tag_id + 1, tag 0 is reserved for untagged cmds*/
                        siop_cmd->cmd_c.tag = xs->xs_tag_id + 1;
                } else {
                        siop_cmd->cmd_c.tag = 0;
                }
                siop_setuptables(&siop_cmd->cmd_c);
                siop_cmd->saved_offset = SIOP_NOOFFSET;
                siop_table_sync(siop_cmd,
                    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
                siop_start(sc, siop_cmd);
                if (xs->xs_control & XS_CTL_POLL) {
                        /* poll for command completion */
                        while ((xs->xs_status & XS_STS_DONE) == 0) {
                                delay(1000);
                                siop_intr(sc);
                        }
                }
                splx(s);
                return;

        case ADAPTER_REQ_GROW_RESOURCES:
#ifdef SIOP_DEBUG
                printf("%s grow resources (%d)\n",
                    device_xname(sc->sc_c.sc_dev),
                    sc->sc_c.sc_adapt.adapt_openings);
#endif
                siop_morecbd(sc);
                return;

        case ADAPTER_REQ_SET_XFER_MODE:
            {
                struct scsipi_xfer_mode *xm = arg;
                if (sc->sc_c.targets[xm->xm_target] == NULL)
                        return;
                s = splbio();
                if (xm->xm_mode & PERIPH_CAP_TQING)
                        sc->sc_c.targets[xm->xm_target]->flags |= TARF_TAG;
                if ((xm->xm_mode & PERIPH_CAP_WIDE16) &&
                    (sc->sc_c.features & SF_BUS_WIDE))
                        sc->sc_c.targets[xm->xm_target]->flags |= TARF_WIDE;
                if (xm->xm_mode & PERIPH_CAP_SYNC)
                        sc->sc_c.targets[xm->xm_target]->flags |= TARF_SYNC;
                if ((xm->xm_mode & (PERIPH_CAP_SYNC | PERIPH_CAP_WIDE16)) ||
                    sc->sc_c.targets[xm->xm_target]->status == TARST_PROBING)
                        sc->sc_c.targets[xm->xm_target]->status =
                            TARST_ASYNC;

                for (lun = 0; lun < sc->sc_c.sc_chan.chan_nluns; lun++) {
                        if (scsipi_lookup_periph(chan,
                            xm->xm_target, lun) != NULL) {
                                /* allocate a lun sw entry for this device */
                                siop_add_dev(sc, xm->xm_target, lun);
                        }
                }

                splx(s);
            }
        }
}

static void
siop_start(struct siop_softc *sc, struct siop_cmd *siop_cmd)
{
        struct siop_lun *siop_lun;
        struct siop_xfer *siop_xfer;
        uint32_t dsa;
        int timeout;
        int target, lun, slot;

        /*
         * first make sure to read valid data
         */
        siop_script_sync(sc, BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);

        /*
         * The queue management here is a bit tricky: the script always looks
         * at the slot from first to last, so if we always use the first
         * free slot commands can stay at the tail of the queue ~forever.
         * The algorithm used here is to restart from the head when we know
         * that the queue is empty, and only add commands after the last one.
         * When we're at the end of the queue wait for the script to clear it.
         * The best thing to do here would be to implement a circular queue,
         * but using only 53c720 features this can be "interesting".
         * A mid-way solution could be to implement 2 queues and swap orders.
         */
        slot = sc->sc_currschedslot;
        /*
         * If the instruction is 0x80000000 (JUMP foo, IF FALSE) the slot is
         * free. As this is the last used slot, all previous slots are free,
         * we can restart from 0.
         */
        if (siop_script_read(sc, (Ent_script_sched_slot0 / 4) + slot * 2) ==
            0x80000000) {
                slot = sc->sc_currschedslot = 0;
        } else {
                slot++;
        }
        target = siop_cmd->cmd_c.xs->xs_periph->periph_target;
        lun = siop_cmd->cmd_c.xs->xs_periph->periph_lun;
        siop_lun =
            ((struct siop_target*)sc->sc_c.targets[target])->siop_lun[lun];
        /* if non-tagged command active, panic: this shouldn't happen */
        if (siop_lun->siop_tag[0].active != NULL) {
                panic("siop_start: tagged cmd while untagged running");
        }
#ifdef DIAGNOSTIC
        /* sanity check the tag if needed */
        if (siop_cmd->cmd_c.flags & CMDFL_TAG) {
                if (siop_lun->siop_tag[siop_cmd->cmd_c.tag].active != NULL)
                        panic("siop_start: tag not free");
                if (siop_cmd->cmd_c.tag >= SIOP_NTAG) {
                        scsipi_printaddr(siop_cmd->cmd_c.xs->xs_periph);
                        printf(": tag id %d\n", siop_cmd->cmd_c.tag);
                        panic("siop_start: invalid tag id");
                }
        }
#endif
        /*
         * find a free scheduler slot and load it.
         */
        for (; slot < SIOP_NSLOTS; slot++) {
                /*
                 * If cmd if 0x80000000 the slot is free
                 */
                if (siop_script_read(sc,
                    (Ent_script_sched_slot0 / 4) + slot * 2) ==
                    0x80000000)
                        break;
        }
        if (slot == SIOP_NSLOTS) {
                /*
                 * no more free slot, no need to continue. freeze the queue
                 * and requeue this command.
                 */
                scsipi_channel_freeze(&sc->sc_c.sc_chan, 1);
                sc->sc_flags |= SCF_CHAN_NOSLOT;
                siop_cmd->cmd_c.xs->error = XS_REQUEUE;
                siop_cmd->cmd_c.xs->status = SCSI_SIOP_NOCHECK;
                siop_scsicmd_end(siop_cmd);
                return;
        }
#ifdef SIOP_DEBUG_SCHED
        printf("using slot %d for DSA 0x%lx\n", slot,
            (u_long)siop_cmd->cmd_c.dsa);
#endif
        /* mark command as active */
        if (siop_cmd->cmd_c.status == CMDST_READY)
                siop_cmd->cmd_c.status = CMDST_ACTIVE;
        else
                panic("siop_start: bad status");
        siop_lun->siop_tag[siop_cmd->cmd_c.tag].active = siop_cmd;
        /* patch scripts with DSA addr */
        dsa = siop_cmd->cmd_c.dsa;
        /* first reselect switch, if we have an entry */
        if (siop_lun->siop_tag[siop_cmd->cmd_c.tag].reseloff > 0)
                siop_script_write(sc,
                    siop_lun->siop_tag[siop_cmd->cmd_c.tag].reseloff + 1,
                    dsa + sizeof(struct siop_common_xfer) +
                    Ent_ldsa_reload_dsa);
        /* CMD script: MOVE MEMORY addr */
        siop_xfer = (struct siop_xfer*)siop_cmd->cmd_tables;
        siop_xfer->resel[E_ldsa_abs_slot_Used[0]] =
            siop_htoc32(&sc->sc_c, sc->sc_c.sc_scriptaddr +
            Ent_script_sched_slot0 + slot * 8);
        siop_table_sync(siop_cmd, BUS_DMASYNC_PREWRITE);
        /* scheduler slot: JUMP ldsa_select */
        siop_script_write(sc,
            (Ent_script_sched_slot0 / 4) + slot * 2 + 1,
            dsa + sizeof(struct siop_common_xfer) + Ent_ldsa_select);
        /* handle timeout */
        if ((siop_cmd->cmd_c.xs->xs_control & XS_CTL_POLL) == 0) {
                /* start exire timer */
                timeout = mstohz(siop_cmd->cmd_c.xs->timeout);
                if (timeout == 0)
                        timeout = 1;
                callout_reset( &siop_cmd->cmd_c.xs->xs_callout,
                    timeout, siop_timeout, siop_cmd);
        }
        /*
         * Change JUMP cmd so that this slot will be handled
         */
        siop_script_write(sc, (Ent_script_sched_slot0 / 4) + slot * 2,
            0x80080000);
        sc->sc_currschedslot = slot;

        /* make sure SCRIPT processor will read valid data */
        siop_script_sync(sc,BUS_DMASYNC_PREREAD |  BUS_DMASYNC_PREWRITE);
        /* Signal script it has some work to do */
        bus_space_write_1(sc->sc_c.sc_rt, sc->sc_c.sc_rh,
            SIOP_ISTAT, ISTAT_SIGP);
        /* and wait for IRQ */
}

void
siop_timeout(void *v)
{
        struct siop_cmd *siop_cmd = v;
        struct siop_softc *sc = (struct siop_softc *)siop_cmd->cmd_c.siop_sc;
        int s;

        scsipi_printaddr(siop_cmd->cmd_c.xs->xs_periph);
        printf("command timeout, CDB: ");
        scsipi_print_cdb(siop_cmd->cmd_c.xs->cmd);
        printf("\n");

        s = splbio();
        /* reset the scsi bus */
        siop_resetbus(&sc->sc_c);

        /* deactivate callout */
        callout_stop(&siop_cmd->cmd_c.xs->xs_callout);
        /* mark command as being timed out; siop_intr will handle it */
        /*
         * mark command has being timed out and just return;
         * the bus reset will generate an interrupt,
         * it will be handled in siop_intr()
         */
        siop_cmd->cmd_c.flags |= CMDFL_TIMEOUT;
        splx(s);
}

void
siop_dump_script(struct siop_softc *sc)
{
        int i;

        for (i = 0; i < PAGE_SIZE / 4; i += 2) {
                printf("0x%04x: 0x%08x 0x%08x", i * 4,
                    siop_script_read(sc, i),
                    siop_script_read(sc, i + 1));
                if ((siop_script_read(sc, i) & 0xe0000000) == 0xc0000000) {
                        i++;
                        printf(" 0x%08x", siop_script_read(sc, i + 1));
                }
                printf("\n");
        }
}

void
siop_morecbd(struct siop_softc *sc)
{
        int error, off, i, j, s;
        bus_dma_segment_t seg;
        int rseg;
        struct siop_cbd *newcbd;
        struct siop_xfer *xfer;
        bus_addr_t dsa;
        uint32_t *scr;

        /* allocate a new list head */
        newcbd = malloc(sizeof(struct siop_cbd), M_DEVBUF, M_NOWAIT|M_ZERO);
        if (newcbd == NULL) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "can't allocate memory for command descriptors head\n");
                return;
        }

        /* allocate cmd list */
        newcbd->cmds = malloc(sizeof(struct siop_cmd) * SIOP_NCMDPB,
            M_DEVBUF, M_NOWAIT|M_ZERO);
        if (newcbd->cmds == NULL) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "can't allocate memory for command descriptors\n");
                goto bad3;
        }
        error = bus_dmamem_alloc(sc->sc_c.sc_dmat, PAGE_SIZE, PAGE_SIZE,
            0, &seg, 1, &rseg, BUS_DMA_NOWAIT);
        if (error) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "unable to allocate cbd DMA memory, error = %d\n",
                    error);
                goto bad2;
        }
        error = bus_dmamem_map(sc->sc_c.sc_dmat, &seg, rseg, PAGE_SIZE,
            (void **)&newcbd->xfers, BUS_DMA_NOWAIT|BUS_DMA_COHERENT);
        if (error) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "unable to map cbd DMA memory, error = %d\n",
                    error);
                goto bad2;
        }
        error = bus_dmamap_create(sc->sc_c.sc_dmat, PAGE_SIZE, 1, PAGE_SIZE, 0,
            BUS_DMA_NOWAIT, &newcbd->xferdma);
        if (error) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "unable to create cbd DMA map, error = %d\n",
                    error);
                goto bad1;
        }
        error = bus_dmamap_load(sc->sc_c.sc_dmat, newcbd->xferdma,
            newcbd->xfers, PAGE_SIZE, NULL, BUS_DMA_NOWAIT);
        if (error) {
                aprint_error_dev(sc->sc_c.sc_dev,
                    "unable to load cbd DMA map, error = %d\n",
                    error);
                goto bad0;
        }
#ifdef SIOP_DEBUG
        printf("%s: alloc newcdb at PHY addr 0x%lx\n",
            device_xname(sc->sc_c.sc_dev),
            (unsigned long)newcbd->xferdma->dm_segs[0].ds_addr);
#endif
        off = (sc->sc_c.features & SF_CHIP_BE) ? 3 : 0;
        for (i = 0; i < SIOP_NCMDPB; i++) {
                error = bus_dmamap_create(sc->sc_c.sc_dmat, MAXPHYS, SIOP_NSG,
                    MAXPHYS, 0, BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW,
                    &newcbd->cmds[i].cmd_c.dmamap_data);
                if (error) {
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "unable to create data DMA map for cbd: "
                            "error %d\n", error);
                        goto bad0;
                }
                error = bus_dmamap_create(sc->sc_c.sc_dmat,
                    sizeof(struct scsipi_generic), 1,
                    sizeof(struct scsipi_generic), 0,
                    BUS_DMA_NOWAIT | BUS_DMA_ALLOCNOW,
                    &newcbd->cmds[i].cmd_c.dmamap_cmd);
                if (error) {
                        aprint_error_dev(sc->sc_c.sc_dev,
                            "unable to create cmd DMA map for cbd %d\n", error);
                        goto bad0;
                }
                newcbd->cmds[i].cmd_c.siop_sc = &sc->sc_c;
                newcbd->cmds[i].siop_cbdp = newcbd;
                xfer = &newcbd->xfers[i];
                newcbd->cmds[i].cmd_tables = (struct siop_common_xfer *)xfer;
                memset(newcbd->cmds[i].cmd_tables, 0, sizeof(struct siop_xfer));
                dsa = newcbd->xferdma->dm_segs[0].ds_addr +
                    i * sizeof(struct siop_xfer);
                newcbd->cmds[i].cmd_c.dsa = dsa;
                newcbd->cmds[i].cmd_c.status = CMDST_FREE;
                xfer->siop_tables.t_msgout.count= siop_htoc32(&sc->sc_c, 1);
                xfer->siop_tables.t_msgout.addr = siop_htoc32(&sc->sc_c, dsa);
                xfer->siop_tables.t_msgin.count= siop_htoc32(&sc->sc_c, 1);
                xfer->siop_tables.t_msgin.addr = siop_htoc32(&sc->sc_c,
                    dsa + offsetof(struct siop_common_xfer, msg_in));
                xfer->siop_tables.t_extmsgin.count= siop_htoc32(&sc->sc_c, 2);
                xfer->siop_tables.t_extmsgin.addr = siop_htoc32(&sc->sc_c,
                    dsa + offsetof(struct siop_common_xfer, msg_in) + 1);
                xfer->siop_tables.t_extmsgdata.addr = siop_htoc32(&sc->sc_c,
                    dsa + offsetof(struct siop_common_xfer, msg_in) + 3);
                xfer->siop_tables.t_status.count= siop_htoc32(&sc->sc_c, 1);
                xfer->siop_tables.t_status.addr = siop_htoc32(&sc->sc_c,
                    dsa + offsetof(struct siop_common_xfer, status) + off);
                /* The select/reselect script */
                scr = &xfer->resel[0];
                for (j = 0; j < __arraycount(load_dsa); j++)
                        scr[j] = siop_htoc32(&sc->sc_c, load_dsa[j]);
                /*
                 * 0x78000000 is a 'move data8 to reg'. data8 is the second
                 * octet, reg offset is the third.
                 */
                scr[Ent_rdsa0 / 4] = siop_htoc32(&sc->sc_c,
                    0x78100000 | ((dsa & 0x000000ff) <<  8));
                scr[Ent_rdsa1 / 4] = siop_htoc32(&sc->sc_c,
                    0x78110000 | ( dsa & 0x0000ff00       ));
                scr[Ent_rdsa2 / 4] = siop_htoc32(&sc->sc_c,
                    0x78120000 | ((dsa & 0x00ff0000) >>  8));
                scr[Ent_rdsa3 / 4] = siop_htoc32(&sc->sc_c,
                    0x78130000 | ((dsa & 0xff000000) >> 16));
                scr[E_ldsa_abs_reselected_Used[0]] = siop_htoc32(&sc->sc_c,
                    sc->sc_c.sc_scriptaddr + Ent_reselected);
                scr[E_ldsa_abs_reselect_Used[0]] = siop_htoc32(&sc->sc_c,
                    sc->sc_c.sc_scriptaddr + Ent_reselect);
                scr[E_ldsa_abs_selected_Used[0]] = siop_htoc32(&sc->sc_c,
                    sc->sc_c.sc_scriptaddr + Ent_selected);
                scr[E_ldsa_abs_data_Used[0]] = siop_htoc32(&sc->sc_c,
                    dsa + sizeof(struct siop_common_xfer) + Ent_ldsa_data);
                /* JUMP foo, IF FALSE - used by MOVE MEMORY to clear the slot */
                scr[Ent_ldsa_data / 4] = siop_htoc32(&sc->sc_c, 0x80000000);
                s = splbio();
                TAILQ_INSERT_TAIL(&sc->free_list, &newcbd->cmds[i], next);
                splx(s);
#ifdef SIOP_DEBUG
                printf("tables[%d]: in=0x%x out=0x%x status=0x%x\n", i,
                    siop_ctoh32(&sc->sc_c,
                        newcbd->cmds[i].cmd_tables->t_msgin.addr),
                    siop_ctoh32(&sc->sc_c,
                        newcbd->cmds[i].cmd_tables->t_msgout.addr),
                    siop_ctoh32(&sc->sc_c,
                        newcbd->cmds[i].cmd_tables->t_status.addr));
#endif
        }
        s = splbio();
        TAILQ_INSERT_TAIL(&sc->cmds, newcbd, next);
        sc->sc_c.sc_adapt.adapt_openings += SIOP_NCMDPB;
        splx(s);
        return;
bad0:
        bus_dmamap_unload(sc->sc_c.sc_dmat, newcbd->xferdma);
        bus_dmamap_destroy(sc->sc_c.sc_dmat, newcbd->xferdma);
bad1:
        bus_dmamem_free(sc->sc_c.sc_dmat, &seg, rseg);
bad2:
        free(newcbd->cmds, M_DEVBUF);
bad3:
        free(newcbd, M_DEVBUF);
}

struct siop_lunsw *
siop_get_lunsw(struct siop_softc *sc)
{
        struct siop_lunsw *lunsw;
        int i;

        if (sc->script_free_lo + __arraycount(lun_switch) >= sc->script_free_hi)
                return NULL;
        lunsw = TAILQ_FIRST(&sc->lunsw_list);
        if (lunsw != NULL) {
#ifdef SIOP_DEBUG
                printf("siop_get_lunsw got lunsw at offset %d\n",
                    lunsw->lunsw_off);
#endif
                TAILQ_REMOVE(&sc->lunsw_list, lunsw, next);
                return lunsw;
        }
        lunsw = malloc(sizeof(struct siop_lunsw), M_DEVBUF, M_NOWAIT|M_ZERO);
        if (lunsw == NULL)
                return NULL;
#ifdef SIOP_DEBUG
        printf("allocating lunsw at offset %d\n", sc->script_free_lo);
#endif
        if (sc->sc_c.features & SF_CHIP_RAM) {
                bus_space_write_region_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh,
                    sc->script_free_lo * 4, lun_switch,
                    __arraycount(lun_switch));
                bus_space_write_4(sc->sc_c.sc_ramt, sc->sc_c.sc_ramh,
                    (sc->script_free_lo + E_abs_lunsw_return_Used[0]) * 4,
                    sc->sc_c.sc_scriptaddr + Ent_lunsw_return);
        } else {
                for (i = 0; i < __arraycount(lun_switch); i++)
                        sc->sc_c.sc_script[sc->script_free_lo + i] =
                            siop_htoc32(&sc->sc_c, lun_switch[i]);
                sc->sc_c.sc_script[
                    sc->script_free_lo + E_abs_lunsw_return_Used[0]] =
                    siop_htoc32(&sc->sc_c,
                        sc->sc_c.sc_scriptaddr + Ent_lunsw_return);
        }
        lunsw->lunsw_off = sc->script_free_lo;
        lunsw->lunsw_size = __arraycount(lun_switch);
        sc->script_free_lo += lunsw->lunsw_size;
        siop_script_sync(sc, BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
        return lunsw;
}

void
siop_add_reselsw(struct siop_softc *sc, int target)
{
        int i, j;
        struct siop_target *siop_target;
        struct siop_lun *siop_lun;

        siop_target = (struct siop_target *)sc->sc_c.targets[target];
        /*
         * add an entry to resel switch
         */
        siop_script_sync(sc, BUS_DMASYNC_POSTWRITE);
        for (i = 0; i < 15; i++) {
                siop_target->reseloff = Ent_resel_targ0 / 4 + i * 2;
                if ((siop_script_read(sc, siop_target->reseloff) & 0xff)
                    == 0xff) { /* it's free */
#ifdef SIOP_DEBUG
                        printf("siop: target %d slot %d offset %d\n",
                            target, i, siop_target->reseloff);
#endif
                        /* JUMP abs_foo, IF target | 0x80; */
                        siop_script_write(sc, siop_target->reseloff,
                            0x800c0080 | target);
                        siop_script_write(sc, siop_target->reseloff + 1,
                            sc->sc_c.sc_scriptaddr +
                            siop_target->lunsw->lunsw_off * 4 +
                            Ent_lun_switch_entry);
                        break;
                }
        }
        if (i == 15) /* no free slot, shouldn't happen */
                panic("siop: resel switch full");

        sc->sc_ntargets++;
        for (i = 0; i < 8; i++) {
                siop_lun = siop_target->siop_lun[i];
                if (siop_lun == NULL)
                        continue;
                if (siop_lun->reseloff > 0) {
                        siop_lun->reseloff = 0;
                        for (j = 0; j < SIOP_NTAG; j++)
                                siop_lun->siop_tag[j].reseloff = 0;
                        siop_add_dev(sc, target, i);
                }
        }
        siop_update_scntl3(sc, sc->sc_c.targets[target]);
        siop_script_sync(sc, BUS_DMASYNC_PREWRITE);
}

void
siop_update_scntl3(struct siop_softc *sc,
    struct siop_common_target *_siop_target)
{
        struct siop_target *siop_target = (struct siop_target *)_siop_target;

        /* MOVE target->id >> 24 TO SCNTL3 */
        siop_script_write(sc,
            siop_target->lunsw->lunsw_off + (Ent_restore_scntl3 / 4),
            0x78030000 | ((siop_target->target_c.id >> 16) & 0x0000ff00));
        /* MOVE target->id >> 8 TO SXFER */
        siop_script_write(sc,
            siop_target->lunsw->lunsw_off + (Ent_restore_scntl3 / 4) + 2,
            0x78050000 | (siop_target->target_c.id & 0x0000ff00));
        siop_script_sync(sc, BUS_DMASYNC_PREWRITE);
}

void
siop_add_dev(struct siop_softc *sc, int target, int lun)
{
        struct siop_lunsw *lunsw;
        struct siop_target *siop_target =
            (struct siop_target *)sc->sc_c.targets[target];
        struct siop_lun *siop_lun = siop_target->siop_lun[lun];
        int i, ntargets;

        if (siop_lun->reseloff > 0)
                return;
        lunsw = siop_target->lunsw;
        if ((lunsw->lunsw_off + lunsw->lunsw_size) < sc->script_free_lo) {
                /*
                 * can't extend this slot. Probably not worth trying to deal
                 * with this case
                 */
#ifdef SIOP_DEBUG
                aprint_error_dev(sc->sc_c.sc_dev,
                    "%d:%d: can't allocate a lun sw slot\n", target, lun);
#endif
                return;
        }
        /* count how many free targets we still have to probe */
        ntargets =  sc->sc_c.sc_chan.chan_ntargets - 1 - sc->sc_ntargets;

        /*
         * we need 8 bytes for the lun sw additional entry, and
         * eventually sizeof(tag_switch) for the tag switch entry.
         * Keep enough free space for the free targets that could be
         * probed later.
         */
        if (sc->script_free_lo + 2 +
            (ntargets * __arraycount(lun_switch)) >=
            ((siop_target->target_c.flags & TARF_TAG) ?
            sc->script_free_hi - __arraycount(tag_switch) :
            sc->script_free_hi)) {
                /*
                 * not enough space, probably not worth dealing with it.
                 * We can hold 13 tagged-queuing capable devices in the 4k RAM.
                 */
#ifdef SIOP_DEBUG
                aprint_error_dev(sc->sc_c.sc_dev,
                    "%d:%d: not enough memory for a lun sw slot\n",
                    target, lun);
#endif
                return;
        }
#ifdef SIOP_DEBUG
        printf("%s:%d:%d: allocate lun sw entry\n",
            device_xname(sc->sc_c.sc_dev), target, lun);
#endif
        /* INT int_resellun */
        siop_script_write(sc, sc->script_free_lo, 0x98080000);
        siop_script_write(sc, sc->script_free_lo + 1, A_int_resellun);
        /* Now the slot entry: JUMP abs_foo, IF lun */
        siop_script_write(sc, sc->script_free_lo - 2,
            0x800c0000 | lun);
        siop_script_write(sc, sc->script_free_lo - 1, 0);
        siop_lun->reseloff = sc->script_free_lo - 2;
        lunsw->lunsw_size += 2;
        sc->script_free_lo += 2;
        if (siop_target->target_c.flags & TARF_TAG) {
                /* we need a tag switch */
                sc->script_free_hi -= __arraycount(tag_switch);
                if (sc->sc_c.features & SF_CHIP_RAM) {
                        bus_space_write_region_4(sc->sc_c.sc_ramt,
                            sc->sc_c.sc_ramh,
                            sc->script_free_hi * 4, tag_switch,
                            __arraycount(tag_switch));
                } else {
                        for(i = 0; i < __arraycount(tag_switch); i++) {
                                sc->sc_c.sc_script[sc->script_free_hi + i] =
                                    siop_htoc32(&sc->sc_c, tag_switch[i]);
                        }
                }
                siop_script_write(sc,
                    siop_lun->reseloff + 1,
                    sc->sc_c.sc_scriptaddr + sc->script_free_hi * 4 +
                    Ent_tag_switch_entry);

                for (i = 0; i < SIOP_NTAG; i++) {
                        siop_lun->siop_tag[i].reseloff =
                            sc->script_free_hi + (Ent_resel_tag0 / 4) + i * 2;
                }
        } else {
                /* non-tag case; just work with the lun switch */
                siop_lun->siop_tag[0].reseloff =
                    siop_target->siop_lun[lun]->reseloff;
        }
        siop_script_sync(sc, BUS_DMASYNC_PREWRITE);
}

void
siop_del_dev(struct siop_softc *sc, int target, int lun)
{
        int i;
        struct siop_target *siop_target;

#ifdef SIOP_DEBUG
        printf("%s:%d:%d: free lun sw entry\n",
            device_xname(sc->sc_c.sc_dev), target, lun);
#endif
        if (sc->sc_c.targets[target] == NULL)
                return;
        siop_target = (struct siop_target *)sc->sc_c.targets[target];
        free(siop_target->siop_lun[lun], M_DEVBUF);
        siop_target->siop_lun[lun] = NULL;
        /* XXX compact sw entry too ? */
        /* check if we can free the whole target */
        for (i = 0; i < 8; i++) {
                if (siop_target->siop_lun[i] != NULL)
                        return;
        }
#ifdef SIOP_DEBUG
        printf("%s: free siop_target for target %d lun %d lunsw offset %d\n",
            device_xname(sc->sc_c.sc_dev), target, lun,
            siop_target->lunsw->lunsw_off);
#endif
        /*
         * nothing here, free the target struct and resel
         * switch entry
         */
        siop_script_write(sc, siop_target->reseloff, 0x800c00ff);
        siop_script_sync(sc, BUS_DMASYNC_PREWRITE);
        TAILQ_INSERT_TAIL(&sc->lunsw_list, siop_target->lunsw, next);
        free(sc->sc_c.targets[target], M_DEVBUF);
        sc->sc_c.targets[target] = NULL;
        sc->sc_ntargets--;
}

#ifdef SIOP_STATS
void
siop_printstats(void)
{

        printf("siop_stat_intr %d\n", siop_stat_intr);
        printf("siop_stat_intr_shortxfer %d\n", siop_stat_intr_shortxfer);
        printf("siop_stat_intr_xferdisc %d\n", siop_stat_intr_xferdisc);
        printf("siop_stat_intr_sdp %d\n", siop_stat_intr_sdp);
        printf("siop_stat_intr_saveoffset %d\n", siop_stat_intr_saveoffset);
        printf("siop_stat_intr_done %d\n", siop_stat_intr_done);
        printf("siop_stat_intr_lunresel %d\n", siop_stat_intr_lunresel);
        printf("siop_stat_intr_qfull %d\n", siop_stat_intr_qfull);
}
#endif