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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 <assert.h>

#include "hw.h"

#include "pci.h"

#include "scsi.h"

#include "block_int.h"

//#define DEBUG_LSI

//#define DEBUG_LSI_REG

#ifdef DEBUG_LSI

#define DPRINTF(fmt, ...) \

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

#define BADF(fmt, ...) \

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

#else

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

#define BADF(fmt, ...) \

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

#endif

#define LSI_MAX_DEVS 7

#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

/* Enable Response to Reselection */

#define LSI_SCID_RRE      0x60

#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 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 = disconnect, 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;

    SCSIBus bus;

    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 dbms;

    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 */

    uint8_t sbr;

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

    uint32_t script_ram[2048];

} LSIState;

static inline int lsi_irq_on_rsl(LSIState *s)

{

    return (s->sien0 & LSI_SIST0_RSL) && (s->scid & LSI_SCID_RRE);

}

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->dbms = 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;

    s->sbr = 0;

}

static int lsi_dma_40bit(LSIState *s)

{

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

        return 1;

    return 0;

}

static int lsi_dma_ti64bit(LSIState *s)

{

    if ((s->ccntl1 & LSI_CCNTL1_EN64TIBMV) == LSI_CCNTL1_EN64TIBMV)

        return 1;

    return 0;

}

static int lsi_dma_64bit(LSIState *s)

{

    if ((s->ccntl1 & LSI_CCNTL1_EN64DBMV) == LSI_CCNTL1_EN64DBMV)

        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 void lsi_reselect(LSIState *s, uint32_t tag);

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 i;

    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->dev.irq[0], level);

    if (!level && lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON)) {

        DPRINTF("Handled IRQs & disconnected, looking for pending "

                "processes\n");

        for (i = 0; i < s->active_commands; i++) {

            if (s->queue[i].pending) {

                lsi_reselect(s, s->queue[i].tag);

                break;

            }

        }

    }

}

/* 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;

    /* both 40 and Table Indirect 64-bit DMAs store upper bits in dnad64 */

    if (lsi_dma_40bit(s) || lsi_dma_ti64bit(s))

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

    else if (s->dbms)

        addr |= ((uint64_t)s->dbms << 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->info->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->info->write_data(s->current_dev, s->current_tag);

        } else {

            /* Request any remaining data.  */

            s->current_dev->info->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;

    /* LSI53C700 Family Compatibility, see LSI53C895A 4-73 */

    if (!s->dcntl & LSI_DCNTL_COM) {

        s->sfbr = 1 << (id & 0x7);

    }

    DPRINTF("Reselected target %d\n", id);

    s->current_dev = s->bus.devs[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];

    }

    if (lsi_irq_on_rsl(s)) {

        lsi_script_scsi_interrupt(s, LSI_SIST0_RSL, 0);

    }

}

/* 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;

            /* Reselect if waiting for it, or if reselection triggers an IRQ

               and the bus is free.

               Since no interrupt stacking is implemented in the emulation, it

               is also required that there are no pending interrupts waiting

               for service from the device driver. */

            if (s->waiting == 1 ||

                (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON) &&

                 !(s->istat0 & (LSI_ISTAT0_SIP | LSI_ISTAT0_DIP)))) {

                /* 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(SCSIBus *bus, int reason, uint32_t tag,

                                 uint32_t arg)

{

    LSIState *s = DO_UPCAST(LSIState, dev.qdev, bus->qbus.parent);

    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 ||

        (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON))) {

        if (lsi_queue_tag(s, tag, arg))

            return;

    }

    /* host adapter (re)connected */

    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->info->send_command(s->current_dev, s->current_tag, buf,

                                           s->current_lun);

    if (n > 0) {

        lsi_set_phase(s, PHASE_DI);

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

    } else if (n < 0) {

        lsi_set_phase(s, PHASE_DO);

        s->current_dev->info->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 0x04:

            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);