/*      $OpenBSD: siop_common.c,v 1.46 2024/09/01 03:08:56 jsg Exp $ */
/*      $NetBSD: siop_common.c,v 1.37 2005/02/27 00:27:02 perry Exp $   */

/*
 * Copyright (c) 2000, 2002 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/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/scsiio.h>
#include <sys/endian.h>

#include <machine/bus.h>

#include <scsi/scsi_all.h>
#include <scsi/scsi_message.h>
#include <scsi/scsiconf.h>

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

#undef DEBUG
#undef DEBUG_DR
#undef DEBUG_NEG

int
siop_common_attach(struct siop_common_softc *sc)
{
        int error, i, buswidth;
        bus_dma_segment_t seg;
        int rseg;

        /*
         * Allocate DMA-safe memory for the script and map it.
         */
        if ((sc->features & SF_CHIP_RAM) == 0) {
                error = bus_dmamem_alloc(sc->sc_dmat, PAGE_SIZE,
                    PAGE_SIZE, 0, &seg, 1, &rseg, BUS_DMA_NOWAIT);
                if (error) {
                        printf("%s: unable to allocate script DMA memory, "
                            "error = %d\n", sc->sc_dev.dv_xname, error);
                        return error;
                }
                error = bus_dmamem_map(sc->sc_dmat, &seg, rseg, PAGE_SIZE,
                    (caddr_t *)&sc->sc_script,
                    BUS_DMA_NOWAIT|BUS_DMA_COHERENT);
                if (error) {
                        printf("%s: unable to map script DMA memory, "
                            "error = %d\n", sc->sc_dev.dv_xname, error);
                        return error;
                }
                error = bus_dmamap_create(sc->sc_dmat, PAGE_SIZE, 1,
                    PAGE_SIZE, 0, BUS_DMA_NOWAIT, &sc->sc_scriptdma);
                if (error) {
                        printf("%s: unable to create script DMA map, "
                            "error = %d\n", sc->sc_dev.dv_xname, error);
                        return error;
                }
                error = bus_dmamap_load(sc->sc_dmat, sc->sc_scriptdma,
                    sc->sc_script, PAGE_SIZE, NULL, BUS_DMA_NOWAIT);
                if (error) {
                        printf("%s: unable to load script DMA map, "
                            "error = %d\n", sc->sc_dev.dv_xname, error);
                        return error;
                }
                sc->sc_scriptaddr =
                    sc->sc_scriptdma->dm_segs[0].ds_addr;
                sc->ram_size = PAGE_SIZE;
        }

        /*
         * sc->sc_link is the template for all device sc_link's
         * for devices attached to this adapter. It is passed to
         * the upper layers in config_found().
         */
        buswidth = (sc->features & SF_BUS_WIDE) ? 16 : 8;
        sc->sc_id = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SCID);
        if (sc->sc_id == 0 || sc->sc_id >= buswidth)
                sc->sc_id = SIOP_DEFAULT_TARGET;

        for (i = 0; i < 16; i++)
                sc->targets[i] = NULL;

        /* find min/max sync period for this chip */
        sc->st_maxsync = 0;
        sc->dt_maxsync = 0;
        sc->st_minsync = 255;
        sc->dt_minsync = 255;
        for (i = 0; i < sizeof(scf_period) / sizeof(scf_period[0]); i++) {
                if (sc->clock_period != scf_period[i].clock)
                        continue;
                if (sc->st_maxsync < scf_period[i].period)
                        sc->st_maxsync = scf_period[i].period;
                if (sc->st_minsync > scf_period[i].period)
                        sc->st_minsync = scf_period[i].period;
        }
        if (sc->st_maxsync == 255 || sc->st_minsync == 0)
                panic("siop: can't find my sync parameters");
        for (i = 0; i < sizeof(dt_scf_period) / sizeof(dt_scf_period[0]); i++) {
                if (sc->clock_period != dt_scf_period[i].clock)
                        continue;
                if (sc->dt_maxsync < dt_scf_period[i].period)
                        sc->dt_maxsync = dt_scf_period[i].period;
                if (sc->dt_minsync > dt_scf_period[i].period)
                        sc->dt_minsync = dt_scf_period[i].period;
        }
        if (sc->dt_maxsync == 255 || sc->dt_minsync == 0)
                panic("siop: can't find my sync parameters");
        return 0;
}

void
siop_common_reset(struct siop_common_softc *sc)
{
        u_int32_t stest3;

        /* reset the chip */
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_ISTAT, ISTAT_SRST);
        delay(1000);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_ISTAT, 0);

        /* init registers */
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL0,
            SCNTL0_ARB_MASK | SCNTL0_EPC | SCNTL0_AAP);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1, 0);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL3, sc->clock_div);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SXFER, 0);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_DIEN, 0xff);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SIEN0,
            0xff & ~(SIEN0_CMP | SIEN0_SEL | SIEN0_RSL));
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SIEN1,
            0xff & ~(SIEN1_HTH | SIEN1_GEN));
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST2, 0);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST3, STEST3_TE);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STIME0,
            (0xb << STIME0_SEL_SHIFT));
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCID,
            sc->sc_id | SCID_RRE);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_RESPID0,
            1 << sc->sc_id);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_DCNTL,
            (sc->features & SF_CHIP_PF) ? DCNTL_COM | DCNTL_PFEN : DCNTL_COM);
        if (sc->features & SF_CHIP_AAIP)
                bus_space_write_1(sc->sc_rt, sc->sc_rh,
                    SIOP_AIPCNTL1, AIPCNTL1_DIS);

        /* enable clock doubler or quadrupler if appropriate */
        if (sc->features & (SF_CHIP_DBLR | SF_CHIP_QUAD)) {
                stest3 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_STEST3);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST1,
                    STEST1_DBLEN);
                if (sc->features & SF_CHIP_QUAD) {
                        /* wait for PPL to lock */
                        while ((bus_space_read_1(sc->sc_rt, sc->sc_rh,
                            SIOP_STEST4) & STEST4_LOCK) == 0)
                                delay(10);
                } else {
                        /* data sheet says 20us - more won't hurt */
                        delay(100);
                }
                /* halt scsi clock, select doubler/quad, restart clock */
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST3,
                    stest3 | STEST3_HSC);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST1,
                    STEST1_DBLEN | STEST1_DBLSEL);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST3, stest3);
        } else {
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST1, 0);
        }
        if (sc->features & SF_CHIP_FIFO)
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST5,
                    bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST5) |
                    CTEST5_DFS);
        if (sc->features & SF_CHIP_LED0) {
                /* Set GPIO0 as output if software LED control is required */
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_GPCNTL,
                    bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_GPCNTL) & 0xfe);
        }
        if (sc->features & SF_BUS_ULTRA3) {
                /* reset SCNTL4 */
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL4, 0);
        }
        sc->mode = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_STEST4) &
            STEST4_MODE_MASK;

        /*
         * initialise the RAM. Without this we may get scsi gross errors on
         * the 1010
         */
        if (sc->features & SF_CHIP_RAM)
                bus_space_set_region_4(sc->sc_ramt, sc->sc_ramh,
                        0, 0, sc->ram_size / 4);
        sc->sc_reset(sc);
}

/* prepare tables before sending a cmd */
void
siop_setuptables(struct siop_common_cmd *siop_cmd)
{
        int i;
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        struct scsi_xfer *xs = siop_cmd->xs;
        int target = xs->sc_link->target;
        int lun = xs->sc_link->lun;
        int msgoffset = 1;
        int *targ_flags = &sc->targets[target]->flags;
        int quirks;

        siop_cmd->siop_tables->id = siop_htoc32(sc, sc->targets[target]->id);
        memset(siop_cmd->siop_tables->msg_out, 0,
            sizeof(siop_cmd->siop_tables->msg_out));
        /* request sense doesn't disconnect */
        if (siop_cmd->status == CMDST_SENSE)
                siop_cmd->siop_tables->msg_out[0] = MSG_IDENTIFY(lun, 0);
        else if ((sc->features & SF_CHIP_GEBUG) &&
            (sc->targets[target]->flags & TARF_ISWIDE) == 0)
                /*
                 * 1010 bug: it seems that the 1010 has problems with reselect
                 * when not in wide mode (generate false SCSI gross error).
                 * The FreeBSD sym driver has comments about it but their
                 * workaround (disable SCSI gross error reporting) doesn't
                 * work with my adapter. So disable disconnect when not
                 * wide.
                 */
                siop_cmd->siop_tables->msg_out[0] = MSG_IDENTIFY(lun, 0);
        else
                siop_cmd->siop_tables->msg_out[0] = MSG_IDENTIFY(lun, 1);
        siop_cmd->siop_tables->t_msgout.count = siop_htoc32(sc, msgoffset);
        if (sc->targets[target]->status == TARST_ASYNC) {
                *targ_flags &= TARF_DT; /* Save TARF_DT 'cuz we don't set it here */
                quirks = xs->sc_link->quirks;

                if ((quirks & SDEV_NOTAGS) == 0)
                        *targ_flags |= TARF_TAG;
                if (((quirks & SDEV_NOWIDE) == 0) &&
                    (sc->features & SF_BUS_WIDE))
                        *targ_flags |= TARF_WIDE;
                if ((quirks & SDEV_NOSYNC) == 0)
                        *targ_flags |= TARF_SYNC;

                if ((sc->features & SF_CHIP_GEBUG) &&
                    (*targ_flags & TARF_WIDE) == 0)
                        /* 
                         * 1010 workaround: can't do disconnect if not wide,
                         * so can't do tag
                         */
                        *targ_flags &= ~TARF_TAG;

                /* Safe to call siop_add_dev() multiple times */
                siop_add_dev((struct siop_softc *)sc, target, lun);

                if ((*targ_flags & TARF_DT) &&
                    (sc->mode == STEST4_MODE_LVD)) {
                        sc->targets[target]->status = TARST_PPR_NEG;
                        siop_ppr_msg(siop_cmd, msgoffset, sc->dt_minsync,
                            sc->maxoff);
                } else if (*targ_flags & TARF_WIDE) {
                        sc->targets[target]->status = TARST_WIDE_NEG;
                        siop_wdtr_msg(siop_cmd, msgoffset,
                            MSG_EXT_WDTR_BUS_16_BIT);
                } else if (*targ_flags & TARF_SYNC) {
                        sc->targets[target]->status = TARST_SYNC_NEG;
                        siop_sdtr_msg(siop_cmd, msgoffset, sc->st_minsync,
                        (sc->maxoff > 31) ? 31 :  sc->maxoff);
                } else {
                        sc->targets[target]->status = TARST_OK;
                        siop_update_xfer_mode(sc, target);
                }
        } else if (sc->targets[target]->status == TARST_OK &&
            (*targ_flags & TARF_TAG) &&
            siop_cmd->status != CMDST_SENSE) {
                siop_cmd->flags |= CMDFL_TAG;
        }
        siop_cmd->siop_tables->status =
            siop_htoc32(sc, SCSI_SIOP_NOSTATUS); /* set invalid status */

        if ((xs->flags & (SCSI_DATA_IN | SCSI_DATA_OUT)) ||
            siop_cmd->status == CMDST_SENSE) {
                bzero(siop_cmd->siop_tables->data,
                    sizeof(siop_cmd->siop_tables->data));
                for (i = 0; i < siop_cmd->dmamap_data->dm_nsegs; i++) {
                        siop_cmd->siop_tables->data[i].count =
                            siop_htoc32(sc,
                                siop_cmd->dmamap_data->dm_segs[i].ds_len);
                        siop_cmd->siop_tables->data[i].addr =
                            siop_htoc32(sc,
                                siop_cmd->dmamap_data->dm_segs[i].ds_addr);
                }
        }
}

int
siop_wdtr_neg(struct siop_common_cmd *siop_cmd)
{
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        struct siop_common_target *siop_target = siop_cmd->siop_target;
        int target = siop_cmd->xs->sc_link->target;
        struct siop_common_xfer *tables = siop_cmd->siop_tables;

        if (siop_target->status == TARST_WIDE_NEG) {
                /* we initiated wide negotiation */
                switch (tables->msg_in[3]) {
                case MSG_EXT_WDTR_BUS_8_BIT:
                        siop_target->flags &= ~TARF_ISWIDE;
                        sc->targets[target]->id &= ~(SCNTL3_EWS << 24);
                        break;
                case MSG_EXT_WDTR_BUS_16_BIT:
                        if (siop_target->flags & TARF_WIDE) {
                                siop_target->flags |= TARF_ISWIDE;
                                sc->targets[target]->id |= (SCNTL3_EWS << 24);
                                break;
                        }
                /* FALLTHROUGH */
                default:
                        /*
                         * hum, we got more than what we can handle, shouldn't
                         * happen. Reject, and stay async
                         */
                        siop_target->flags &= ~TARF_ISWIDE;
                        siop_target->status = TARST_OK;
                        siop_target->offset = siop_target->period = 0;
                        siop_update_xfer_mode(sc, target);
                        printf("%s: rejecting invalid wide negotiation from "
                            "target %d (%d)\n", sc->sc_dev.dv_xname, target,
                            tables->msg_in[3]);
                        tables->t_msgout.count = siop_htoc32(sc, 1);
                        tables->msg_out[0] = MSG_MESSAGE_REJECT;
                        return SIOP_NEG_MSGOUT;
                }
                tables->id = siop_htoc32(sc, sc->targets[target]->id);
                bus_space_write_1(sc->sc_rt, sc->sc_rh,
                    SIOP_SCNTL3,
                    (sc->targets[target]->id >> 24) & 0xff);
                /* we now need to do sync */
                if (siop_target->flags & TARF_SYNC) {
                        siop_target->status = TARST_SYNC_NEG;
                        siop_sdtr_msg(siop_cmd, 0, sc->st_minsync,
                            (sc->maxoff > 31) ? 31 : sc->maxoff);
                        return SIOP_NEG_MSGOUT;
                } else {
                        siop_target->status = TARST_OK;
                        siop_update_xfer_mode(sc, target);
                        return SIOP_NEG_ACK;
                }
        } else {
                /* target initiated wide negotiation */
                if (tables->msg_in[3] >= MSG_EXT_WDTR_BUS_16_BIT
                    && (siop_target->flags & TARF_WIDE)) {
                        siop_target->flags |= TARF_ISWIDE;
                        sc->targets[target]->id |= SCNTL3_EWS << 24;
                } else {
                        siop_target->flags &= ~TARF_ISWIDE;
                        sc->targets[target]->id &= ~(SCNTL3_EWS << 24);
                }
                tables->id = siop_htoc32(sc, sc->targets[target]->id);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL3,
                    (sc->targets[target]->id >> 24) & 0xff);
                /*
                 * we did reset wide parameters, so fall back to async,
                 * but don't schedule a sync neg, target should initiate it
                 */
                siop_target->status = TARST_OK;
                siop_target->offset = siop_target->period = 0;
                siop_update_xfer_mode(sc, target);
                siop_wdtr_msg(siop_cmd, 0, (siop_target->flags & TARF_ISWIDE) ?
                    MSG_EXT_WDTR_BUS_16_BIT : MSG_EXT_WDTR_BUS_8_BIT);
                return SIOP_NEG_MSGOUT;
        }
}

int
siop_ppr_neg(struct siop_common_cmd *siop_cmd)
{
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        struct siop_common_target *siop_target = siop_cmd->siop_target;
        int target = siop_cmd->xs->sc_link->target;
        struct siop_common_xfer *tables = siop_cmd->siop_tables;
        int sync, offset, options, scf = 0;
        int i;

#ifdef DEBUG_NEG
        printf("%s: answer on ppr negotiation:", sc->sc_dev.dv_xname);
        for (i = 0; i < 8; i++)
                printf(" 0x%x", tables->msg_in[i]);
        printf("\n");
#endif

        if (siop_target->status == TARST_PPR_NEG) {
                /* we initiated PPR negotiation */
                sync = tables->msg_in[3];
                offset = tables->msg_in[5];
                options = tables->msg_in[7];
                if (options != MSG_EXT_PPR_PROT_DT) {
                        /* shouldn't happen */
                        printf("%s: ppr negotiation for target %d: "
                            "no DT option\n", sc->sc_dev.dv_xname, target);
                        siop_target->status = TARST_ASYNC;
                        siop_target->flags &= ~(TARF_DT | TARF_ISDT);
                        siop_target->offset = 0;
                        siop_target->period = 0;
                        goto reject;
                }

                if (offset > sc->maxoff || sync < sc->dt_minsync ||
                    sync > sc->dt_maxsync) {
                        printf("%s: ppr negotiation for target %d: "
                            "offset (%d) or sync (%d) out of range\n",
                            sc->sc_dev.dv_xname, target, offset, sync);
                        /* should not happen */
                        siop_target->status = TARST_ASYNC;
                        siop_target->flags &= ~(TARF_DT | TARF_ISDT);
                        siop_target->offset = 0;
                        siop_target->period = 0;
                        goto reject;
                } else {
                        for (i = 0; i <
                            sizeof(dt_scf_period) / sizeof(dt_scf_period[0]);
                            i++) {
                                if (sc->clock_period != dt_scf_period[i].clock)
                                        continue;
                                if (dt_scf_period[i].period == sync) {
                                        /* ok, found it. we now are sync. */
                                        siop_target->offset = offset;
                                        siop_target->period = sync;
                                        scf = dt_scf_period[i].scf;
                                        siop_target->flags |= TARF_ISDT;
                                }
                        }
                        if ((siop_target->flags & TARF_ISDT) == 0) {
                                printf("%s: ppr negotiation for target %d: "
                                    "sync (%d) incompatible with adapter\n",
                                    sc->sc_dev.dv_xname, target, sync);
                                /*
                                 * we didn't find it in our table, do async
                                 * send reject msg, start SDTR/WDTR neg
                                 */
                                siop_target->status = TARST_ASYNC;
                                siop_target->flags &= ~(TARF_DT | TARF_ISDT);
                                siop_target->offset = 0;
                                siop_target->period = 0;
                                goto reject;
                        }
                }
                if (tables->msg_in[6] != 1) {
                        printf("%s: ppr negotiation for target %d: "
                            "transfer width (%d) incompatible with dt\n",
                            sc->sc_dev.dv_xname, target, tables->msg_in[6]);
                        /* DT mode can only be done with wide transfers */
                        siop_target->status = TARST_ASYNC;
                        siop_target->flags &= ~(TARF_DT | TARF_ISDT);
                        siop_target->offset = 0;
                        siop_target->period = 0;
                        goto reject;
                }
                siop_target->flags |= TARF_ISWIDE;
                sc->targets[target]->id |= (SCNTL3_EWS << 24);
                sc->targets[target]->id &= ~(SCNTL3_SCF_MASK << 24);
                sc->targets[target]->id |= scf << (24 + SCNTL3_SCF_SHIFT);
                sc->targets[target]->id &= ~(SXFER_MO_MASK << 8);
                sc->targets[target]->id |=
                    (siop_target->offset & SXFER_MO_MASK) << 8;
                sc->targets[target]->id &= ~0xff;
                sc->targets[target]->id |= SCNTL4_U3EN;
                siop_target->status = TARST_OK;
                siop_update_xfer_mode(sc, target);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL3,
                    (sc->targets[target]->id >> 24) & 0xff);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SXFER,
                    (sc->targets[target]->id >> 8) & 0xff);
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL4,
                    sc->targets[target]->id & 0xff);
                return SIOP_NEG_ACK;
        } else {
                /* target initiated PPR negotiation, shouldn't happen */
                printf("%s: rejecting invalid PPR negotiation from "
                    "target %d\n", sc->sc_dev.dv_xname, target);
reject:
                tables->t_msgout.count = siop_htoc32(sc, 1);
                tables->msg_out[0] = MSG_MESSAGE_REJECT;
                return SIOP_NEG_MSGOUT;
        }
}

int
siop_sdtr_neg(struct siop_common_cmd *siop_cmd)
{
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        struct siop_common_target *siop_target = siop_cmd->siop_target;
        int target = siop_cmd->xs->sc_link->target;
        int sync, maxoffset, offset, i;
        int send_msgout = 0;
        struct siop_common_xfer *tables = siop_cmd->siop_tables;

        /* limit to Ultra/2 parameters, need PPR for Ultra/3 */
        maxoffset = (sc->maxoff > 31) ? 31 : sc->maxoff;

        sync = tables->msg_in[3];
        offset = tables->msg_in[4];

        if (siop_target->status == TARST_SYNC_NEG) {
                /* we initiated sync negotiation */
                siop_target->status = TARST_OK;
#ifdef DEBUG
                printf("sdtr: sync %d offset %d\n", sync, offset);
#endif
                if (offset > maxoffset || sync < sc->st_minsync ||
                        sync > sc->st_maxsync)
                        goto reject;
                for (i = 0; i < sizeof(scf_period) / sizeof(scf_period[0]);
                    i++) {
                        if (sc->clock_period != scf_period[i].clock)
                                continue;
                        if (scf_period[i].period == sync) {
                                /* ok, found it. we now are sync. */
                                siop_target->offset = offset;
                                siop_target->period = sync;
                                sc->targets[target]->id &=
                                    ~(SCNTL3_SCF_MASK << 24);
                                sc->targets[target]->id |= scf_period[i].scf
                                    << (24 + SCNTL3_SCF_SHIFT);
                                if (sync < 25 && /* Ultra */
                                    (sc->features & SF_BUS_ULTRA3) == 0)
                                        sc->targets[target]->id |=
                                            SCNTL3_ULTRA << 24;
                                else
                                        sc->targets[target]->id &=
                                            ~(SCNTL3_ULTRA << 24);
                                sc->targets[target]->id &=
                                    ~(SXFER_MO_MASK << 8);
                                sc->targets[target]->id |=
                                    (offset & SXFER_MO_MASK) << 8;
                                sc->targets[target]->id &= ~0xff; /* scntl4 */
                                goto end;
                        }
                }
                /*
                 * we didn't find it in our table, do async and send reject
                 * msg
                 */
reject:
                send_msgout = 1;
                tables->t_msgout.count = siop_htoc32(sc, 1);
                tables->msg_out[0] = MSG_MESSAGE_REJECT;
                sc->targets[target]->id &= ~(SCNTL3_SCF_MASK << 24);
                sc->targets[target]->id &= ~(SCNTL3_ULTRA << 24);
                sc->targets[target]->id &= ~(SXFER_MO_MASK << 8);
                sc->targets[target]->id &= ~0xff; /* scntl4 */
                siop_target->offset = siop_target->period = 0;
        } else { /* target initiated sync neg */
#ifdef DEBUG
                printf("sdtr (target): sync %d offset %d\n", sync, offset);
#endif
                if (offset == 0 || sync > sc->st_maxsync) { /* async */
                        goto async;
                }
                if (offset > maxoffset)
                        offset = maxoffset;
                if (sync < sc->st_minsync)
                        sync = sc->st_minsync;
                /* look for sync period */
                for (i = 0; i < sizeof(scf_period) / sizeof(scf_period[0]);
                    i++) {
                        if (sc->clock_period != scf_period[i].clock)
                                continue;
                        if (scf_period[i].period == sync) {
                                /* ok, found it. we now are sync. */
                                siop_target->offset = offset;
                                siop_target->period = sync;
                                sc->targets[target]->id &=
                                    ~(SCNTL3_SCF_MASK << 24);
                                sc->targets[target]->id |= scf_period[i].scf
                                    << (24 + SCNTL3_SCF_SHIFT);
                                if (sync < 25 && /* Ultra */
                                    (sc->features & SF_BUS_ULTRA3) == 0)
                                        sc->targets[target]->id |=
                                            SCNTL3_ULTRA << 24;
                                else
                                        sc->targets[target]->id &=
                                            ~(SCNTL3_ULTRA << 24);
                                sc->targets[target]->id &=
                                    ~(SXFER_MO_MASK << 8);
                                sc->targets[target]->id |=
                                    (offset & SXFER_MO_MASK) << 8;
                                sc->targets[target]->id &= ~0xff; /* scntl4 */
                                siop_sdtr_msg(siop_cmd, 0, sync, offset);
                                send_msgout = 1;
                                goto end;
                        }
                }
async:
                siop_target->offset = siop_target->period = 0;
                sc->targets[target]->id &= ~(SCNTL3_SCF_MASK << 24);
                sc->targets[target]->id &= ~(SCNTL3_ULTRA << 24);
                sc->targets[target]->id &= ~(SXFER_MO_MASK << 8);
                sc->targets[target]->id &= ~0xff; /* scntl4 */
                siop_sdtr_msg(siop_cmd, 0, 0, 0);
                send_msgout = 1;
        }
end:
        if (siop_target->status == TARST_OK)
                siop_update_xfer_mode(sc, target);
#ifdef DEBUG
        printf("id now 0x%x\n", sc->targets[target]->id);
#endif
        tables->id = siop_htoc32(sc, sc->targets[target]->id);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL3,
            (sc->targets[target]->id >> 24) & 0xff);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SXFER,
            (sc->targets[target]->id >> 8) & 0xff);
        if (send_msgout) {
                return SIOP_NEG_MSGOUT;
        } else {
                return SIOP_NEG_ACK;
        }
}

void
siop_sdtr_msg(struct siop_common_cmd *siop_cmd, int offset, int ssync, int soff)
{
        siop_cmd->siop_tables->msg_out[offset + 0] = MSG_EXTENDED;
        siop_cmd->siop_tables->msg_out[offset + 1] = MSG_EXT_SDTR_LEN;
        siop_cmd->siop_tables->msg_out[offset + 2] = MSG_EXT_SDTR;
        siop_cmd->siop_tables->msg_out[offset + 3] = ssync;
        siop_cmd->siop_tables->msg_out[offset + 4] = soff;
        siop_cmd->siop_tables->t_msgout.count =
            siop_htoc32(siop_cmd->siop_sc, offset + MSG_EXT_SDTR_LEN + 2);
}

void
siop_wdtr_msg(struct siop_common_cmd *siop_cmd, int offset, int wide)
{
        siop_cmd->siop_tables->msg_out[offset + 0] = MSG_EXTENDED;
        siop_cmd->siop_tables->msg_out[offset + 1] = MSG_EXT_WDTR_LEN;
        siop_cmd->siop_tables->msg_out[offset + 2] = MSG_EXT_WDTR;
        siop_cmd->siop_tables->msg_out[offset + 3] = wide;
        siop_cmd->siop_tables->t_msgout.count =
            siop_htoc32(siop_cmd->siop_sc, offset + MSG_EXT_WDTR_LEN + 2);
}

void
siop_ppr_msg(struct siop_common_cmd *siop_cmd, int offset, int ssync, int soff)
{
        siop_cmd->siop_tables->msg_out[offset + 0] = MSG_EXTENDED;
        siop_cmd->siop_tables->msg_out[offset + 1] = MSG_EXT_PPR_LEN;
        siop_cmd->siop_tables->msg_out[offset + 2] = MSG_EXT_PPR;
        siop_cmd->siop_tables->msg_out[offset + 3] = ssync;
        siop_cmd->siop_tables->msg_out[offset + 4] = 0; /* reserved */
        siop_cmd->siop_tables->msg_out[offset + 5] = soff;
        siop_cmd->siop_tables->msg_out[offset + 6] = 1; /* wide */
        siop_cmd->siop_tables->msg_out[offset + 7] = MSG_EXT_PPR_PROT_DT;
        siop_cmd->siop_tables->t_msgout.count =
            siop_htoc32(siop_cmd->siop_sc, offset + MSG_EXT_PPR_LEN + 2);
}

void
siop_ma(struct siop_common_cmd *siop_cmd)
{
        int offset, dbc, sstat;
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        scr_table_t *table; /* table with partial xfer */

        /*
         * compute how much of the current table didn't get handled when
         * a phase mismatch occurs
         */
        if ((siop_cmd->xs->flags & (SCSI_DATA_OUT | SCSI_DATA_IN))
            == 0)
            return; /* no valid data transfer */

        offset = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SCRATCHA + 1);
        if (offset >= SIOP_NSG) {
                printf("%s: bad offset in siop_sdp (%d)\n",
                    sc->sc_dev.dv_xname, offset);
                return;
        }
        table = &siop_cmd->siop_tables->data[offset];
#ifdef DEBUG_DR
        printf("siop_ma: offset %d count=%d addr=0x%x ", offset,
            table->count, table->addr);
#endif
        dbc = bus_space_read_4(sc->sc_rt, sc->sc_rh, SIOP_DBC) & 0x00ffffff;
        if (siop_cmd->xs->flags & SCSI_DATA_OUT) {
                if (sc->features & SF_CHIP_DFBC) {
                        dbc +=
                            bus_space_read_2(sc->sc_rt, sc->sc_rh, SIOP_DFBC);
                } else {
                        /* need to account stale data in FIFO */
                        int dfifo =
                            bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_DFIFO);
                        if (sc->features & SF_CHIP_FIFO) {
                                dfifo |= (bus_space_read_1(sc->sc_rt, sc->sc_rh,
                                    SIOP_CTEST5) & CTEST5_BOMASK) << 8;
                                dbc += (dfifo - (dbc & 0x3ff)) & 0x3ff;
                        } else {
                                dbc += (dfifo - (dbc & 0x7f)) & 0x7f;
                        }
                }
                sstat = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SSTAT0);
                if (sstat & SSTAT0_OLF)
                        dbc++;
                if ((sstat & SSTAT0_ORF) && (sc->features & SF_CHIP_DFBC) == 0)
                        dbc++;
                if (siop_cmd->siop_target->flags & TARF_ISWIDE) {
                        sstat = bus_space_read_1(sc->sc_rt, sc->sc_rh,
                            SIOP_SSTAT2);
                        if (sstat & SSTAT2_OLF1)
                                dbc++;
                        if ((sstat & SSTAT2_ORF1) &&
                            (sc->features & SF_CHIP_DFBC) == 0)
                                dbc++;
                }
                /* clear the FIFO */
                bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3,
                    bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3) |
                    CTEST3_CLF);
        }
        siop_cmd->flags |= CMDFL_RESID;
        siop_cmd->resid = dbc;
}

void
siop_sdp(struct siop_common_cmd *siop_cmd, int offset)
{
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        scr_table_t *table;

        if ((siop_cmd->xs->flags & (SCSI_DATA_OUT | SCSI_DATA_IN))== 0)
                return; /* no data pointers to save */

        /*
         * offset == SIOP_NSG may be a valid condition if we get a Save data
         * pointer when the xfer is done. Just ignore the Save data pointer
         * in this case
         */
        if (offset == SIOP_NSG)
                return;
#ifdef DIAGNOSTIC
        if (offset > SIOP_NSG) {
                sc_print_addr(siop_cmd->xs->sc_link);
                printf("offset %d > %d\n", offset, SIOP_NSG);
                panic("siop_sdp: offset");
        }
#endif
        /*
         * Save data pointer. We do this by adjusting the tables to point
         * at the beginning of the data not yet transferred.
         * offset points to the first table with untransferred data.
         */

        /*
         * before doing that we decrease resid from the amount of data which
         * has been transferred.
         */
        siop_update_resid(siop_cmd, offset);

        /*
         * First let see if we have a resid from a phase mismatch. If so,
         * we have to adjust the table at offset to remove transferred data.
         */
        if (siop_cmd->flags & CMDFL_RESID) {
                siop_cmd->flags &= ~CMDFL_RESID;
                table = &siop_cmd->siop_tables->data[offset];
                /* "cut" already transferred data from this table */
                table->addr =
                    siop_htoc32(sc, siop_ctoh32(sc, table->addr) +
                    siop_ctoh32(sc, table->count) - siop_cmd->resid);
                table->count = siop_htoc32(sc, siop_cmd->resid);
        }

        /*
         * now we can remove entries which have been transferred.
         * We just move the entries with data left at the beginning of the
         * tables
         */
        bcopy(&siop_cmd->siop_tables->data[offset],
            &siop_cmd->siop_tables->data[0],
            (SIOP_NSG - offset) * sizeof(scr_table_t));
}

void
siop_update_resid(struct siop_common_cmd *siop_cmd, int offset)
{
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        scr_table_t *table;
        int i;

        if ((siop_cmd->xs->flags & (SCSI_DATA_OUT | SCSI_DATA_IN))
            == 0)
            return; /* no data to transfer */

        /*
         * update resid. First account for the table entries which have
         * been fully completed.
         */
        for (i = 0; i < offset; i++)
                siop_cmd->xs->resid -=
                    siop_ctoh32(sc, siop_cmd->siop_tables->data[i].count);
        /*
         * if CMDFL_RESID is set, the last table (pointed by offset) is a
         * partial transfers. If not, offset points to the entry following
         * the last full transfer.
         */
        if (siop_cmd->flags & CMDFL_RESID) {
                table = &siop_cmd->siop_tables->data[offset];
                siop_cmd->xs->resid -=
                    siop_ctoh32(sc, table->count) - siop_cmd->resid;
        }
}

int
siop_iwr(struct siop_common_cmd *siop_cmd)
{
        int offset;
        scr_table_t *table; /* table with IWR */
        struct siop_common_softc *sc = siop_cmd->siop_sc;
        /* handle ignore wide residue messages */

        /* if target isn't wide, reject */
        if ((siop_cmd->siop_target->flags & TARF_ISWIDE) == 0) {
                siop_cmd->siop_tables->t_msgout.count = siop_htoc32(sc, 1);
                siop_cmd->siop_tables->msg_out[0] = MSG_MESSAGE_REJECT;
                return SIOP_NEG_MSGOUT;
        }
        /* get index of current command in table */
        offset = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SCRATCHA + 1);
        /*
         * if the current table did complete, we're now pointing at the
         * next one. Go back one if we didn't see a phase mismatch.
         */
        if ((siop_cmd->flags & CMDFL_RESID) == 0)
                offset--;
        table = &siop_cmd->siop_tables->data[offset];

        if ((siop_cmd->flags & CMDFL_RESID) == 0) {
                if (siop_ctoh32(sc, table->count) & 1) {
                        /* we really got the number of bytes we expected */
                        return SIOP_NEG_ACK;
                } else {
                        /*
                         * now we really had a short xfer, by one byte.
                         * handle it just as if we had a phase mismatch
                         * (there is a resid of one for this table).
                         * Update scratcha1 to reflect the fact that
                         * this xfer isn't complete.
                         */
                         siop_cmd->flags |= CMDFL_RESID;
                         siop_cmd->resid = 1;
                         bus_space_write_1(sc->sc_rt, sc->sc_rh,
                             SIOP_SCRATCHA + 1, offset);
                         return SIOP_NEG_ACK;
                }
        } else {
                /*
                 * we already have a short xfer for this table; it's
                 * just one byte less than we though it was
                 */
                siop_cmd->resid--;
                return SIOP_NEG_ACK;
        }
}

void
siop_clearfifo(struct siop_common_softc *sc)
{
        int timeout = 0;
        int ctest3 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3);

#ifdef DEBUG_INTR
        printf("DMA fifo not empty !\n");
#endif
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3,
            ctest3 | CTEST3_CLF);
        while ((bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3) &
            CTEST3_CLF) != 0) {
                delay(1);
                if (++timeout > 1000) {
                        printf("clear fifo failed\n");
                        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_CTEST3,
                            bus_space_read_1(sc->sc_rt, sc->sc_rh,
                            SIOP_CTEST3) & ~CTEST3_CLF);
                        return;
                }
        }
}

int
siop_modechange(struct siop_common_softc *sc)
{
        int retry;
        int sist0, sist1, stest2;
        for (retry = 0; retry < 5; retry++) {
                /*
                 * datasheet says to wait 100ms and re-read SIST1,
                 * to check that DIFFSENSE is stable.
                 * We may delay() 5 times for  100ms at interrupt time;
                 * hopefully this will not happen often.
                 */
                delay(100000);
                sist0 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SIST0);
                sist1 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SIST1);
                if (sist1 & SIEN1_SBMC)
                        continue; /* we got an irq again */
                sc->mode = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_STEST4) &
                    STEST4_MODE_MASK;
                stest2 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_STEST2);
                switch(sc->mode) {
                case STEST4_MODE_DIF:
                        printf("%s: switching to differential mode\n",
                            sc->sc_dev.dv_xname);
                        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST2,
                            stest2 | STEST2_DIF);
                        break;
                case STEST4_MODE_SE:
                        printf("%s: switching to single-ended mode\n",
                            sc->sc_dev.dv_xname);
                        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST2,
                            stest2 & ~STEST2_DIF);
                        break;
                case STEST4_MODE_LVD:
                        printf("%s: switching to LVD mode\n",
                            sc->sc_dev.dv_xname);
                        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_STEST2,
                            stest2 & ~STEST2_DIF);
                        break;
                default:
                        printf("%s: invalid SCSI mode 0x%x\n",
                            sc->sc_dev.dv_xname, sc->mode);
                        return 0;
                }
                return 1;
        }
        printf("%s: timeout waiting for DIFFSENSE to stabilise\n",
            sc->sc_dev.dv_xname);
        return 0;
}

void
siop_resetbus(struct siop_common_softc *sc)
{
        int scntl1;
        scntl1 = bus_space_read_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1,
            scntl1 | SCNTL1_RST);
        /* minimum 25 us, more time won't hurt */
        delay(100);
        bus_space_write_1(sc->sc_rt, sc->sc_rh, SIOP_SCNTL1, scntl1);
}

void
siop_update_xfer_mode(struct siop_common_softc *sc, int target)
{
        struct siop_common_target *siop_target;

        siop_target = sc->targets[target];

        printf("%s: target %d now using %s%s%d bit ",
            sc->sc_dev.dv_xname, target,
            (siop_target->flags & TARF_TAG) ? "tagged " : "",
            (siop_target->flags & TARF_ISDT) ? "DT " : "",
            (siop_target->flags & TARF_ISWIDE) ? 16 : 8);

        if (siop_target->offset == 0)
                printf("async ");
        else {
                switch (siop_target->period) {
                case 9: /*   12.5ns cycle */
                        printf("80.0");
                        break;
                case 10: /*  25  ns cycle */
                        printf("40.0");
                        break;
                case 12: /*  48  ns cycle */
                        printf("20.0");
                        break;
                case 18: /*  72  ns cycle */
                        printf("13.3");
                        break;
                case 25: /* 100  ns cycle */
                        printf("10.0");
                        break;
                case 37: /* 118  ns cycle */
                        printf("6.67");
                        break;
                case 50: /* 200  ns cycle */
                        printf("5.0");
                        break;
                case 75: /* 300  ns cycle */
                        printf("3.33");
                        break;
                default:
                        printf("??");
                        break;
                }
                printf(" MHz %d REQ/ACK offset ", siop_target->offset);
        }

        printf("xfers\n");

        if ((sc->features & SF_CHIP_GEBUG) &&
            (siop_target->flags & TARF_ISWIDE) == 0)
                /* 1010 workaround: can't do disconnect if not wide, so can't do tag */
                siop_target->flags &= ~TARF_TAG;
}