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/*

 * QEMU LSI53C895A SCSI Host Bus Adapter emulation

 *

 * Copyright (c) 2006 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the LGPL.

 */

/* ??? Need to check if the {read,write}[wl] routines work properly on

   big-endian targets.  */

#include "hw.h"

#include "pci.h"

#include "scsi-disk.h"

//#define DEBUG_LSI

//#define DEBUG_LSI_REG

#ifdef DEBUG_LSI

#define DPRINTF(fmt, args...) \

do { printf("lsi_scsi: " fmt , ##args); } while (0)

#define BADF(fmt, args...) \

do { fprintf(stderr, "lsi_scsi: error: " fmt , ##args); exit(1);} while (0)

#else

#define DPRINTF(fmt, args...) do {} while(0)

#define BADF(fmt, args...) \

do { fprintf(stderr, "lsi_scsi: error: " fmt , ##args);} while (0)

#endif

#define LSI_SCNTL0_TRG    0x01

#define LSI_SCNTL0_AAP    0x02

#define LSI_SCNTL0_EPC    0x08

#define LSI_SCNTL0_WATN   0x10

#define LSI_SCNTL0_START  0x20

#define LSI_SCNTL1_SST    0x01

#define LSI_SCNTL1_IARB   0x02

#define LSI_SCNTL1_AESP   0x04

#define LSI_SCNTL1_RST    0x08

#define LSI_SCNTL1_CON    0x10

#define LSI_SCNTL1_DHP    0x20

#define LSI_SCNTL1_ADB    0x40

#define LSI_SCNTL1_EXC    0x80

#define LSI_SCNTL2_WSR    0x01

#define LSI_SCNTL2_VUE0   0x02

#define LSI_SCNTL2_VUE1   0x04

#define LSI_SCNTL2_WSS    0x08

#define LSI_SCNTL2_SLPHBEN 0x10

#define LSI_SCNTL2_SLPMD  0x20

#define LSI_SCNTL2_CHM    0x40

#define LSI_SCNTL2_SDU    0x80

#define LSI_ISTAT0_DIP    0x01

#define LSI_ISTAT0_SIP    0x02

#define LSI_ISTAT0_INTF   0x04

#define LSI_ISTAT0_CON    0x08

#define LSI_ISTAT0_SEM    0x10

#define LSI_ISTAT0_SIGP   0x20

#define LSI_ISTAT0_SRST   0x40

#define LSI_ISTAT0_ABRT   0x80

#define LSI_ISTAT1_SI     0x01

#define LSI_ISTAT1_SRUN   0x02

#define LSI_ISTAT1_FLSH   0x04

#define LSI_SSTAT0_SDP0   0x01

#define LSI_SSTAT0_RST    0x02

#define LSI_SSTAT0_WOA    0x04

#define LSI_SSTAT0_LOA    0x08

#define LSI_SSTAT0_AIP    0x10

#define LSI_SSTAT0_OLF    0x20

#define LSI_SSTAT0_ORF    0x40

#define LSI_SSTAT0_ILF    0x80

#define LSI_SIST0_PAR     0x01

#define LSI_SIST0_RST     0x02

#define LSI_SIST0_UDC     0x04

#define LSI_SIST0_SGE     0x08

#define LSI_SIST0_RSL     0x10

#define LSI_SIST0_SEL     0x20

#define LSI_SIST0_CMP     0x40

#define LSI_SIST0_MA      0x80

#define LSI_SIST1_HTH     0x01

#define LSI_SIST1_GEN     0x02

#define LSI_SIST1_STO     0x04

#define LSI_SIST1_SBMC    0x10

#define LSI_SOCL_IO       0x01

#define LSI_SOCL_CD       0x02

#define LSI_SOCL_MSG      0x04

#define LSI_SOCL_ATN      0x08

#define LSI_SOCL_SEL      0x10

#define LSI_SOCL_BSY      0x20

#define LSI_SOCL_ACK      0x40

#define LSI_SOCL_REQ      0x80

#define LSI_DSTAT_IID     0x01

#define LSI_DSTAT_SIR     0x04

#define LSI_DSTAT_SSI     0x08

#define LSI_DSTAT_ABRT    0x10

#define LSI_DSTAT_BF      0x20

#define LSI_DSTAT_MDPE    0x40

#define LSI_DSTAT_DFE     0x80

#define LSI_DCNTL_COM     0x01

#define LSI_DCNTL_IRQD    0x02

#define LSI_DCNTL_STD     0x04

#define LSI_DCNTL_IRQM    0x08

#define LSI_DCNTL_SSM     0x10

#define LSI_DCNTL_PFEN    0x20

#define LSI_DCNTL_PFF     0x40

#define LSI_DCNTL_CLSE    0x80

#define LSI_DMODE_MAN     0x01

#define LSI_DMODE_BOF     0x02

#define LSI_DMODE_ERMP    0x04

#define LSI_DMODE_ERL     0x08

#define LSI_DMODE_DIOM    0x10

#define LSI_DMODE_SIOM    0x20

#define LSI_CTEST2_DACK   0x01

#define LSI_CTEST2_DREQ   0x02

#define LSI_CTEST2_TEOP   0x04

#define LSI_CTEST2_PCICIE 0x08

#define LSI_CTEST2_CM     0x10

#define LSI_CTEST2_CIO    0x20

#define LSI_CTEST2_SIGP   0x40

#define LSI_CTEST2_DDIR   0x80

#define LSI_CTEST5_BL2    0x04

#define LSI_CTEST5_DDIR   0x08

#define LSI_CTEST5_MASR   0x10

#define LSI_CTEST5_DFSN   0x20

#define LSI_CTEST5_BBCK   0x40

#define LSI_CTEST5_ADCK   0x80

#define LSI_CCNTL0_DILS   0x01

#define LSI_CCNTL0_DISFC  0x10

#define LSI_CCNTL0_ENNDJ  0x20

#define LSI_CCNTL0_PMJCTL 0x40

#define LSI_CCNTL0_ENPMJ  0x80

#define LSI_CCNTL1_EN64DBMV  0x01

#define LSI_CCNTL1_EN64TIBMV 0x02

#define LSI_CCNTL1_64TIMOD   0x04

#define LSI_CCNTL1_DDAC      0x08

#define LSI_CCNTL1_ZMOD      0x80

#define LSI_CCNTL1_40BIT (LSI_CCNTL1_EN64TIBMV|LSI_CCNTL1_64TIMOD)

#define PHASE_DO          0

#define PHASE_DI          1

#define PHASE_CMD         2

#define PHASE_ST          3

#define PHASE_MO          6

#define PHASE_MI          7

#define PHASE_MASK        7

/* Maximum length of MSG IN data.  */

#define LSI_MAX_MSGIN_LEN 8

/* Flag set if this is a tagged command.  */

#define LSI_TAG_VALID     (1 << 16)

typedef struct {

    uint32_t tag;

    uint32_t pending;

    int out;

} lsi_queue;

typedef struct {

    PCIDevice pci_dev;

    int mmio_io_addr;

    int ram_io_addr;

    uint32_t script_ram_base;

    int carry; /* ??? Should this be an a visible register somewhere?  */

    int sense;

    /* Action to take at the end of a MSG IN phase.

       0 = COMMAND, 1 = disconect, 2 = DATA OUT, 3 = DATA IN.  */

    int msg_action;

    int msg_len;

    uint8_t msg[LSI_MAX_MSGIN_LEN];

    /* 0 if SCRIPTS are running or stopped.

     * 1 if a Wait Reselect instruction has been issued.

     * 2 if processing DMA from lsi_execute_script.

     * 3 if a DMA operation is in progress.  */

    int waiting;

    SCSIDevice *scsi_dev[LSI_MAX_DEVS];

    SCSIDevice *current_dev;

    int current_lun;

    /* The tag is a combination of the device ID and the SCSI tag.  */

    uint32_t current_tag;

    uint32_t current_dma_len;

    int command_complete;

    uint8_t *dma_buf;

    lsi_queue *queue;

    int queue_len;

    int active_commands;

    uint32_t dsa;

    uint32_t temp;

    uint32_t dnad;

    uint32_t dbc;

    uint8_t istat0;

    uint8_t istat1;

    uint8_t dcmd;

    uint8_t dstat;

    uint8_t dien;

    uint8_t sist0;

    uint8_t sist1;

    uint8_t sien0;

    uint8_t sien1;

    uint8_t mbox0;

    uint8_t mbox1;

    uint8_t dfifo;

    uint8_t ctest2;

    uint8_t ctest3;

    uint8_t ctest4;

    uint8_t ctest5;

    uint8_t ccntl0;

    uint8_t ccntl1;

    uint32_t dsp;

    uint32_t dsps;

    uint8_t dmode;

    uint8_t dcntl;

    uint8_t scntl0;

    uint8_t scntl1;

    uint8_t scntl2;

    uint8_t scntl3;

    uint8_t sstat0;

    uint8_t sstat1;

    uint8_t scid;

    uint8_t sxfer;

    uint8_t socl;

    uint8_t sdid;

    uint8_t ssid;

    uint8_t sfbr;

    uint8_t stest1;

    uint8_t stest2;

    uint8_t stest3;

    uint8_t sidl;

    uint8_t stime0;

    uint8_t respid0;

    uint8_t respid1;

    uint32_t mmrs;

    uint32_t mmws;

    uint32_t sfs;

    uint32_t drs;

    uint32_t sbms;

    uint32_t dmbs;

    uint32_t dnad64;

    uint32_t pmjad1;

    uint32_t pmjad2;

    uint32_t rbc;

    uint32_t ua;

    uint32_t ia;

    uint32_t sbc;

    uint32_t csbc;

    uint32_t scratch[18]; /* SCRATCHA-SCRATCHR */

    /* Script ram is stored as 32-bit words in host byteorder.  */

    uint32_t script_ram[2048];

} LSIState;

static void lsi_soft_reset(LSIState *s)

{

    DPRINTF("Reset\n");

    s->carry = 0;

    s->waiting = 0;

    s->dsa = 0;

    s->dnad = 0;

    s->dbc = 0;

    s->temp = 0;

    memset(s->scratch, 0, sizeof(s->scratch));

    s->istat0 = 0;

    s->istat1 = 0;

    s->dcmd = 0;

    s->dstat = 0;

    s->dien = 0;

    s->sist0 = 0;

    s->sist1 = 0;

    s->sien0 = 0;

    s->sien1 = 0;

    s->mbox0 = 0;

    s->mbox1 = 0;

    s->dfifo = 0;

    s->ctest2 = 0;

    s->ctest3 = 0;

    s->ctest4 = 0;

    s->ctest5 = 0;

    s->ccntl0 = 0;

    s->ccntl1 = 0;

    s->dsp = 0;

    s->dsps = 0;

    s->dmode = 0;

    s->dcntl = 0;

    s->scntl0 = 0xc0;

    s->scntl1 = 0;

    s->scntl2 = 0;

    s->scntl3 = 0;

    s->sstat0 = 0;

    s->sstat1 = 0;

    s->scid = 7;

    s->sxfer = 0;

    s->socl = 0;

    s->stest1 = 0;

    s->stest2 = 0;

    s->stest3 = 0;

    s->sidl = 0;

    s->stime0 = 0;

    s->respid0 = 0x80;

    s->respid1 = 0;

    s->mmrs = 0;

    s->mmws = 0;

    s->sfs = 0;

    s->drs = 0;

    s->sbms = 0;

    s->dmbs = 0;

    s->dnad64 = 0;

    s->pmjad1 = 0;

    s->pmjad2 = 0;

    s->rbc = 0;

    s->ua = 0;

    s->ia = 0;

    s->sbc = 0;

    s->csbc = 0;

}

static int lsi_dma_40bit(LSIState *s)

{

    if ((s->ccntl1 & LSI_CCNTL1_40BIT) == LSI_CCNTL1_40BIT)

        return 1;

    return 0;

}

static uint8_t lsi_reg_readb(LSIState *s, int offset);

static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val);

static void lsi_execute_script(LSIState *s);

static inline uint32_t read_dword(LSIState *s, uint32_t addr)

{

    uint32_t buf;

    /* Optimize reading from SCRIPTS RAM.  */

    if ((addr & 0xffffe000) == s->script_ram_base) {

        return s->script_ram[(addr & 0x1fff) >> 2];

    }

    cpu_physical_memory_read(addr, (uint8_t *)&buf, 4);

    return cpu_to_le32(buf);

}

static void lsi_stop_script(LSIState *s)

{

    s->istat1 &= ~LSI_ISTAT1_SRUN;

}

static void lsi_update_irq(LSIState *s)

{

    int level;

    static int last_level;

    /* It's unclear whether the DIP/SIP bits should be cleared when the

       Interrupt Status Registers are cleared or when istat0 is read.

       We currently do the formwer, which seems to work.  */

    level = 0;

    if (s->dstat) {

        if (s->dstat & s->dien)

            level = 1;

        s->istat0 |= LSI_ISTAT0_DIP;

    } else {

        s->istat0 &= ~LSI_ISTAT0_DIP;

    }

    if (s->sist0 || s->sist1) {

        if ((s->sist0 & s->sien0) || (s->sist1 & s->sien1))

            level = 1;

        s->istat0 |= LSI_ISTAT0_SIP;

    } else {

        s->istat0 &= ~LSI_ISTAT0_SIP;

    }

    if (s->istat0 & LSI_ISTAT0_INTF)

        level = 1;

    if (level != last_level) {

        DPRINTF("Update IRQ level %d dstat %02x sist %02x%02x\n",

                level, s->dstat, s->sist1, s->sist0);

        last_level = level;

    }

    qemu_set_irq(s->pci_dev.irq[0], level);

}

/* Stop SCRIPTS execution and raise a SCSI interrupt.  */

static void lsi_script_scsi_interrupt(LSIState *s, int stat0, int stat1)

{

    uint32_t mask0;

    uint32_t mask1;

    DPRINTF("SCSI Interrupt 0x%02x%02x prev 0x%02x%02x\n",

            stat1, stat0, s->sist1, s->sist0);

    s->sist0 |= stat0;

    s->sist1 |= stat1;

    /* Stop processor on fatal or unmasked interrupt.  As a special hack

       we don't stop processing when raising STO.  Instead continue

       execution and stop at the next insn that accesses the SCSI bus.  */

    mask0 = s->sien0 | ~(LSI_SIST0_CMP | LSI_SIST0_SEL | LSI_SIST0_RSL);

    mask1 = s->sien1 | ~(LSI_SIST1_GEN | LSI_SIST1_HTH);

    mask1 &= ~LSI_SIST1_STO;

    if (s->sist0 & mask0 || s->sist1 & mask1) {

        lsi_stop_script(s);

    }

    lsi_update_irq(s);

}

/* Stop SCRIPTS execution and raise a DMA interrupt.  */

static void lsi_script_dma_interrupt(LSIState *s, int stat)

{

    DPRINTF("DMA Interrupt 0x%x prev 0x%x\n", stat, s->dstat);

    s->dstat |= stat;

    lsi_update_irq(s);

    lsi_stop_script(s);

}

static inline void lsi_set_phase(LSIState *s, int phase)

{

    s->sstat1 = (s->sstat1 & ~PHASE_MASK) | phase;

}

static void lsi_bad_phase(LSIState *s, int out, int new_phase)

{

    /* Trigger a phase mismatch.  */

    if (s->ccntl0 & LSI_CCNTL0_ENPMJ) {

        if ((s->ccntl0 & LSI_CCNTL0_PMJCTL) || out) {

            s->dsp = s->pmjad1;

        } else {

            s->dsp = s->pmjad2;

        }

        DPRINTF("Data phase mismatch jump to %08x\n", s->dsp);

    } else {

        DPRINTF("Phase mismatch interrupt\n");

        lsi_script_scsi_interrupt(s, LSI_SIST0_MA, 0);

        lsi_stop_script(s);

    }

    lsi_set_phase(s, new_phase);

}

/* Resume SCRIPTS execution after a DMA operation.  */

static void lsi_resume_script(LSIState *s)

{

    if (s->waiting != 2) {

        s->waiting = 0;

        lsi_execute_script(s);

    } else {

        s->waiting = 0;

    }

}

/* Initiate a SCSI layer data transfer.  */

static void lsi_do_dma(LSIState *s, int out)

{

    uint32_t count;

    target_phys_addr_t addr;

    if (!s->current_dma_len) {

        /* Wait until data is available.  */

        DPRINTF("DMA no data available\n");

        return;

    }

    count = s->dbc;

    if (count > s->current_dma_len)

        count = s->current_dma_len;

    addr = s->dnad;

    if (lsi_dma_40bit(s))

        addr |= ((uint64_t)s->dnad64 << 32);

    else if (s->sbms)

        addr |= ((uint64_t)s->sbms << 32);

    DPRINTF("DMA addr=0x" TARGET_FMT_plx " len=%d\n", addr, count);

    s->csbc += count;

    s->dnad += count;

    s->dbc -= count;

    if (s->dma_buf == NULL) {

        s->dma_buf = s->current_dev->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.  */

            s->current_dev->write_data(s->current_dev, s->current_tag);

        } else {

            /* Request any remaining data.  */

            s->current_dev->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 = qemu_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;

        s->command_complete = 2;

        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;

    s->command_complete = 1;

    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];

    s->command_complete = 0;

    n = s->current_dev->send_command(s->current_dev, s->current_tag, buf,

                                     s->current_lun);

    if (n > 0) {

        lsi_set_phase(s, PHASE_DI);

        s->current_dev->read_data(s->current_dev, s->current_tag);

    } else if (n < 0) {

        lsi_set_phase(s, PHASE_DO);

        s->current_dev->write_data(s->current_dev, s->current_tag);

    }

    if (!s->command_complete) {

        if (n) {

            /* Command did not complete immediately so disconnect.  */

            lsi_add_msg_byte(s, 2); /* SAVE DATA POINTER */

            lsi_add_msg_byte(s, 4); /* DISCONNECT */

            /* wait data */

            lsi_set_phase(s, PHASE_MI);

            s->msg_action = 1;

            lsi_queue_command(s);

        } else {

            /* wait command complete */

            lsi_set_phase(s, PHASE_DI);

        }

    }

}

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, addr_high;

    int opcode;

    int insn_processed = 0;

    s->istat1 |= LSI_ISTAT1_SRUN;

again:

    insn_processed++;

    insn = read_dword(s, s->dsp);

    if (!insn) {

        /* If we receive an empty opcode increment the DSP by 4 bytes

           instead of 8 and execute the next opcode at that location */

        s->dsp += 4;

        goto again;

    }

    addr = read_dword(s, s->dsp + 4);

    addr_high = 0;

    DPRINTF("SCRIPTS dsp=%08x opcode %08x arg %08x\n", s->dsp, insn, addr);