lsi53c895a.c

qemu性能直逼VMware的仿真器QEMU 的模擬速度約為實機的 25％；約為 Bochs 的 60 倍。Plex86、User-Mode-Linux、VMware 和 Virtual PC 則比

    if (s->dma_buf == NULL) {
        s->dma_buf = scsi_get_buf(s->current_dev, s->current_tag);
    }

    /* ??? Set SFBR to first data byte.  */
    if (out) {
        cpu_physical_memory_read(addr, s->dma_buf, count);
    } else {
        cpu_physical_memory_write(addr, s->dma_buf, count);
    }
    s->current_dma_len -= count;
    if (s->current_dma_len == 0) {
        s->dma_buf = NULL;
        if (out) {
            /* Write the data.  */
            scsi_write_data(s->current_dev, s->current_tag);
        } else {
            /* Request any remaining data.  */
            scsi_read_data(s->current_dev, s->current_tag);
        }
    } else {
        s->dma_buf += count;
        lsi_resume_script(s);
    }
}


/* Add a command to the queue.  */
static void lsi_queue_command(LSIState *s)
{
    lsi_queue *p;

    DPRINTF("Queueing tag=0x%x\n", s->current_tag);
    if (s->queue_len == s->active_commands) {
        s->queue_len++;
        s->queue = realloc(s->queue, s->queue_len * sizeof(lsi_queue));
    }
    p = &s->queue[s->active_commands++];
    p->tag = s->current_tag;
    p->pending = 0;
    p->out = (s->sstat1 & PHASE_MASK) == PHASE_DO;
}

/* Queue a byte for a MSG IN phase.  */
static void lsi_add_msg_byte(LSIState *s, uint8_t data)
{
    if (s->msg_len >= LSI_MAX_MSGIN_LEN) {
        BADF("MSG IN data too long\n");
    } else {
        DPRINTF("MSG IN 0x%02x\n", data);
        s->msg[s->msg_len++] = data;
    }
}

/* Perform reselection to continue a command.  */
static void lsi_reselect(LSIState *s, uint32_t tag)
{
    lsi_queue *p;
    int n;
    int id;

    p = NULL;
    for (n = 0; n < s->active_commands; n++) {
        p = &s->queue[n];
        if (p->tag == tag)
            break;
    }
    if (n == s->active_commands) {
        BADF("Reselected non-existant command tag=0x%x\n", tag);
        return;
    }
    id = (tag >> 8) & 0xf;
    s->ssid = id | 0x80;
    DPRINTF("Reselected target %d\n", id);
    s->current_dev = s->scsi_dev[id];
    s->current_tag = tag;
    s->scntl1 |= LSI_SCNTL1_CON;
    lsi_set_phase(s, PHASE_MI);
    s->msg_action = p->out ? 2 : 3;
    s->current_dma_len = p->pending;
    s->dma_buf = NULL;
    lsi_add_msg_byte(s, 0x80);
    if (s->current_tag & LSI_TAG_VALID) {
        lsi_add_msg_byte(s, 0x20);
        lsi_add_msg_byte(s, tag & 0xff);
    }

    s->active_commands--;
    if (n != s->active_commands) {
        s->queue[n] = s->queue[s->active_commands];
    }
}

/* Record that data is available for a queued command.  Returns zero if
   the device was reselected, nonzero if the IO is deferred.  */
static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t arg)
{
    lsi_queue *p;
    int i;
    for (i = 0; i < s->active_commands; i++) {
        p = &s->queue[i];
        if (p->tag == tag) {
            if (p->pending) {
                BADF("Multiple IO pending for tag %d\n", tag);
            }
            p->pending = arg;
            if (s->waiting == 1) {
                /* Reselect device.  */
                lsi_reselect(s, tag);
                return 0;
            } else {
               DPRINTF("Queueing IO tag=0x%x\n", tag);
                p->pending = arg;
                return 1;
            }
        }
    }
    BADF("IO with unknown tag %d\n", tag);
    return 1;
}

/* Callback to indicate that the SCSI layer has completed a transfer.  */
static void lsi_command_complete(void *opaque, int reason, uint32_t tag,
                                 uint32_t arg)
{
    LSIState *s = (LSIState *)opaque;
    int out;

    out = (s->sstat1 & PHASE_MASK) == PHASE_DO;
    if (reason == SCSI_REASON_DONE) {
        DPRINTF("Command complete sense=%d\n", (int)arg);
        s->sense = arg;
        if (s->waiting && s->dbc != 0) {
            /* Raise phase mismatch for short transfers.  */
            lsi_bad_phase(s, out, PHASE_ST);
        } else {
            lsi_set_phase(s, PHASE_ST);
        }
        lsi_resume_script(s);
        return;
    }

    if (s->waiting == 1 || tag != s->current_tag) {
        if (lsi_queue_tag(s, tag, arg))
            return;
    }
    DPRINTF("Data ready tag=0x%x len=%d\n", tag, arg);
    s->current_dma_len = arg;
    if (!s->waiting)
        return;
    if (s->waiting == 1 || s->dbc == 0) {
        lsi_resume_script(s);
    } else {
        lsi_do_dma(s, out);
    }
}

static void lsi_do_command(LSIState *s)
{
    uint8_t buf[16];
    int n;

    DPRINTF("Send command len=%d\n", s->dbc);
    if (s->dbc > 16)
        s->dbc = 16;
    cpu_physical_memory_read(s->dnad, buf, s->dbc);
    s->sfbr = buf[0];
    n = scsi_send_command(s->current_dev, s->current_tag, buf, s->current_lun);
    if (n > 0) {
        lsi_set_phase(s, PHASE_DI);
        scsi_read_data(s->current_dev, s->current_tag);
    } else if (n < 0) {
        lsi_set_phase(s, PHASE_DO);
        scsi_write_data(s->current_dev, s->current_tag);
    }
    if (n && s->current_dma_len == 0) {
        /* Command did not complete immediately so disconnect.  */
        lsi_add_msg_byte(s, 2); /* SAVE DATA POINTER */
        lsi_add_msg_byte(s, 4); /* DISCONNECT */
        lsi_set_phase(s, PHASE_MI);
        s->msg_action = 1;
        lsi_queue_command(s);
    }
}

static void lsi_do_status(LSIState *s)
{
    uint8_t sense;
    DPRINTF("Get status len=%d sense=%d\n", s->dbc, s->sense);
    if (s->dbc != 1)
        BADF("Bad Status move\n");
    s->dbc = 1;
    sense = s->sense;
    s->sfbr = sense;
    cpu_physical_memory_write(s->dnad, &sense, 1);
    lsi_set_phase(s, PHASE_MI);
    s->msg_action = 1;
    lsi_add_msg_byte(s, 0); /* COMMAND COMPLETE */
}

static void lsi_disconnect(LSIState *s)
{
    s->scntl1 &= ~LSI_SCNTL1_CON;
    s->sstat1 &= ~PHASE_MASK;
}

static void lsi_do_msgin(LSIState *s)
{
    int len;
    DPRINTF("Message in len=%d/%d\n", s->dbc, s->msg_len);
    s->sfbr = s->msg[0];
    len = s->msg_len;
    if (len > s->dbc)
        len = s->dbc;
    cpu_physical_memory_write(s->dnad, s->msg, len);
    /* Linux drivers rely on the last byte being in the SIDL.  */
    s->sidl = s->msg[len - 1];
    s->msg_len -= len;
    if (s->msg_len) {
        memmove(s->msg, s->msg + len, s->msg_len);
    } else {
        /* ??? Check if ATN (not yet implemented) is asserted and maybe
           switch to PHASE_MO.  */
        switch (s->msg_action) {
        case 0:
            lsi_set_phase(s, PHASE_CMD);
            break;
        case 1:
            lsi_disconnect(s);
            break;
        case 2:
            lsi_set_phase(s, PHASE_DO);
            break;
        case 3:
            lsi_set_phase(s, PHASE_DI);
            break;
        default:
            abort();
        }
    }
}

/* Read the next byte during a MSGOUT phase.  */
static uint8_t lsi_get_msgbyte(LSIState *s)
{
    uint8_t data;
    cpu_physical_memory_read(s->dnad, &data, 1);
    s->dnad++;
    s->dbc--;
    return data;
}

static void lsi_do_msgout(LSIState *s)
{
    uint8_t msg;
    int len;

    DPRINTF("MSG out len=%d\n", s->dbc);
    while (s->dbc) {
        msg = lsi_get_msgbyte(s);
        s->sfbr = msg;

        switch (msg) {
        case 0x00:
            DPRINTF("MSG: Disconnect\n");
            lsi_disconnect(s);
            break;
        case 0x08:
            DPRINTF("MSG: No Operation\n");
            lsi_set_phase(s, PHASE_CMD);
            break;
        case 0x01:
            len = lsi_get_msgbyte(s);
            msg = lsi_get_msgbyte(s);
            DPRINTF("Extended message 0x%x (len %d)\n", msg, len);
            switch (msg) {
            case 1:
                DPRINTF("SDTR (ignored)\n");
                s->dbc -= 2;
                break;
            case 3:
                DPRINTF("WDTR (ignored)\n");
                s->dbc -= 1;
                break;
            default:
                goto bad;
            }
            break;
        case 0x20: /* SIMPLE queue */
            s->current_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
            DPRINTF("SIMPLE queue tag=0x%x\n", s->current_tag & 0xff);
            break;
        case 0x21: /* HEAD of queue */
            BADF("HEAD queue not implemented\n");
            s->current_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
            break;
        case 0x22: /* ORDERED queue */
            BADF("ORDERED queue not implemented\n");
            s->current_tag |= lsi_get_msgbyte(s) | LSI_TAG_VALID;
            break;
        default:
            if ((msg & 0x80) == 0) {
                goto bad;
            }
            s->current_lun = msg & 7;
            DPRINTF("Select LUN %d\n", s->current_lun);
            lsi_set_phase(s, PHASE_CMD);
            break;
        }
    }
    return;
bad:
    BADF("Unimplemented message 0x%02x\n", msg);
    lsi_set_phase(s, PHASE_MI);
    lsi_add_msg_byte(s, 7); /* MESSAGE REJECT */
    s->msg_action = 0;
}

/* Sign extend a 24-bit value.  */
static inline int32_t sxt24(int32_t n)
{
    return (n << 8) >> 8;
}

static void lsi_memcpy(LSIState *s, uint32_t dest, uint32_t src, int count)
{
    int n;
    uint8_t buf[TARGET_PAGE_SIZE];

    DPRINTF("memcpy dest 0x%08x src 0x%08x count %d\n", dest, src, count);
    while (count) {
        n = (count > TARGET_PAGE_SIZE) ? TARGET_PAGE_SIZE : count;
        cpu_physical_memory_read(src, buf, n);
        cpu_physical_memory_write(dest, buf, n);
        src += n;
        dest += n;
        count -= n;
    }
}

static void lsi_wait_reselect(LSIState *s)
{
    int i;
    DPRINTF("Wait Reselect\n");
    if (s->current_dma_len)
        BADF("Reselect with pending DMA\n");
    for (i = 0; i < s->active_commands; i++) {
        if (s->queue[i].pending) {
            lsi_reselect(s, s->queue[i].tag);
            break;
        }
    }
    if (s->current_dma_len == 0) {
        s->waiting = 1;
    }
}

static void lsi_execute_script(LSIState *s)
{
    uint32_t insn;
    uint32_t addr;
    int opcode;

    s->istat1 |= LSI_ISTAT1_SRUN;
again:
    insn = read_dword(s, s->dsp);
    addr = read_dword(s, s->dsp + 4);
    DPRINTF("SCRIPTS dsp=%08x opcode %08x arg %08x\n", s->dsp, insn, addr);
    s->dsps = addr;
    s->dcmd = insn >> 24;
    s->dsp += 8;
    switch (insn >> 30) {
    case 0: /* Block move.  */
        if (s->sist1 & LSI_SIST1_STO) {
            DPRINTF("Delayed select timeout\n");
            lsi_stop_script(s);
            break;
        }
        s->dbc = insn & 0xffffff;
        s->rbc = s->dbc;
        if (insn & (1 << 29)) {
            /* Indirect addressing.  */
            addr = read_dword(s, addr);
        } else if (insn & (1 << 28)) {
            uint32_t buf[2];
            int32_t offset;
            /* Table indirect addressing.  */
            offset = sxt24(addr);
            cpu_physical_memory_read(s->dsa + offset, (uint8_t *)buf, 8);
            s->dbc = cpu_to_le32(buf[0]);
            addr = cpu_to_le32(buf[1]);
        }
        if ((s->sstat1 & PHASE_MASK) != ((insn >> 24) & 7)) {
            DPRINTF("Wrong phase got %d expected %d\n",
                    s->sstat1 & PHASE_MASK, (insn >> 24) & 7);
            lsi_script_scsi_interrupt(s, LSI_SIST0_MA, 0);
            break;
        }
        s->dnad = addr;
        switch (s->sstat1 & 0x7) {
        case PHASE_DO:
            s->waiting = 2;
            lsi_do_dma(s, 1);
            if (s->waiting)
                s->waiting = 3;
            break;
        case PHASE_DI:
            s->waiting = 2;
            lsi_do_dma(s, 0);
            if (s->waiting)
                s->waiting = 3;
            break;
        case PHASE_CMD:
            lsi_do_command(s);
            break;
        case PHASE_ST:
            lsi_do_status(s);
            break;
        case PHASE_MO:
            lsi_do_msgout(s);
            break;
        case PHASE_MI:
            lsi_do_msgin(s);
            break;
        default:
            BADF("Unimplemented phase %d\n", s->sstat1 & PHASE_MASK);
            exit(1);
        }
        s->dfifo = s->dbc & 0xff;
        s->ctest5 = (s->ctest5 & 0xfc) | ((s->dbc >> 8) & 3);
        s->sbc = s->dbc;
        s->rbc -= s->dbc;
        s->ua = addr + s->dbc;
        /* ??? Set ESA.  */
        s->ia = s->dsp - 8;
        break;

    case 1: /* IO or Read/Write instruction.  */
        opcode = (insn >> 27) & 7;
        if (opcode < 5) {
            uint32_t id;

            if (insn & (1 << 25)) {
                id = read_dword(s, s->dsa + sxt24(insn));
            } else {
                id = addr;
            }
            id = (id >> 16) & 0xf;
            if (insn & (1 << 26)) {
                addr = s->dsp + sxt24(addr);
            }
            s->dnad = addr;
            switch (opcode) {
            case 0: /* Select */
                s->sdid = id;
                if (s->current_dma_len && (s->ssid & 0xf) == id) {
                    DPRINTF("Already reselected by target %d\n", id);
                    break;
                }
                s->sstat0 |= LSI_SSTAT0_WOA;
                s->scntl1 &= ~LSI_SCNTL1_IARB;
                if (id >= LSI_MAX_DEVS || !s->scsi_dev[id]) {
                    DPRINTF("Selected absent target %d\n", id);
                    lsi_script_scsi_interrupt(s, 0, LSI_SIST1_STO);
                    lsi_disconnect(s);
                    break;
                }