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/*

 * QEMU ESP/NCR53C9x emulation

 * 

 * Copyright (c) 2005-2006 Fabrice Bellard

 * 

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "vl.h"

/* debug ESP card */

//#define DEBUG_ESP

/*

 * On Sparc32, this is the ESP (NCR53C90) part of chip STP2000 (Master I/O), also

 * produced as NCR89C100. See

 * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C100.txt

 * and

 * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR53C9X.txt

 */

#ifdef DEBUG_ESP

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

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

#else

#define DPRINTF(fmt, args...)

#endif

#define ESP_MAXREG 0x3f

#define TI_BUFSZ 32

typedef struct ESPState ESPState;

struct ESPState {

    BlockDriverState **bd;

    uint8_t rregs[ESP_MAXREG];

    uint8_t wregs[ESP_MAXREG];

    int32_t ti_size;

    uint32_t ti_rptr, ti_wptr;

    uint8_t ti_buf[TI_BUFSZ];

    int sense;

    int dma;

    SCSIDevice *scsi_dev[MAX_DISKS];

    SCSIDevice *current_dev;

    uint8_t cmdbuf[TI_BUFSZ];

    int cmdlen;

    int do_cmd;

    /* The amount of data left in the current DMA transfer.  */

    uint32_t dma_left;

    /* The size of the current DMA transfer.  Zero if no transfer is in

       progress.  */

    uint32_t dma_counter;

    uint8_t *async_buf;

    uint32_t async_len;

    void *dma_opaque;

};

#define STAT_DO 0x00

#define STAT_DI 0x01

#define STAT_CD 0x02

#define STAT_ST 0x03

#define STAT_MI 0x06

#define STAT_MO 0x07

#define STAT_TC 0x10

#define STAT_PE 0x20

#define STAT_GE 0x40

#define STAT_IN 0x80

#define INTR_FC 0x08

#define INTR_BS 0x10

#define INTR_DC 0x20

#define INTR_RST 0x80

#define SEQ_0 0x0

#define SEQ_CD 0x4

static int get_cmd(ESPState *s, uint8_t *buf)

{

    uint32_t dmalen;

    int target;

    dmalen = s->rregs[0] | (s->rregs[1] << 8);

    target = s->wregs[4] & 7;

    DPRINTF("get_cmd: len %d target %d\n", dmalen, target);

    if (s->dma) {

        espdma_memory_read(s->dma_opaque, buf, dmalen);

    } else {

        buf[0] = 0;

        memcpy(&buf[1], s->ti_buf, dmalen);

        dmalen++;

    }

    s->ti_size = 0;

    s->ti_rptr = 0;

    s->ti_wptr = 0;

    if (s->current_dev) {

        /* Started a new command before the old one finished.  Cancel it.  */

        scsi_cancel_io(s->current_dev, 0);

        s->async_len = 0;

    }

    if (target >= MAX_DISKS || !s->scsi_dev[target]) {

        // No such drive

        s->rregs[4] = STAT_IN;

        s->rregs[5] = INTR_DC;

        s->rregs[6] = SEQ_0;

        espdma_raise_irq(s->dma_opaque);

        return 0;

    }

    s->current_dev = s->scsi_dev[target];

    return dmalen;

}

static void do_cmd(ESPState *s, uint8_t *buf)

{

    int32_t datalen;

    int lun;

    DPRINTF("do_cmd: busid 0x%x\n", buf[0]);

    lun = buf[0] & 7;

    datalen = scsi_send_command(s->current_dev, 0, &buf[1], lun);

    s->ti_size = datalen;

    if (datalen != 0) {

        s->rregs[4] = STAT_IN | STAT_TC;

        s->dma_left = 0;

        s->dma_counter = 0;

        if (datalen > 0) {

            s->rregs[4] |= STAT_DI;

            scsi_read_data(s->current_dev, 0);

        } else {

            s->rregs[4] |= STAT_DO;

            scsi_write_data(s->current_dev, 0);

        }

    }

    s->rregs[5] = INTR_BS | INTR_FC;

    s->rregs[6] = SEQ_CD;

    espdma_raise_irq(s->dma_opaque);

}

static void handle_satn(ESPState *s)

{

    uint8_t buf[32];

    int len;

    len = get_cmd(s, buf);

    if (len)

        do_cmd(s, buf);

}

static void handle_satn_stop(ESPState *s)

{

    s->cmdlen = get_cmd(s, s->cmdbuf);

    if (s->cmdlen) {

        DPRINTF("Set ATN & Stop: cmdlen %d\n", s->cmdlen);

        s->do_cmd = 1;

        s->rregs[4] = STAT_IN | STAT_TC | STAT_CD;

        s->rregs[5] = INTR_BS | INTR_FC;

        s->rregs[6] = SEQ_CD;

        espdma_raise_irq(s->dma_opaque);

    }

}

static void write_response(ESPState *s)

{

    DPRINTF("Transfer status (sense=%d)\n", s->sense);

    s->ti_buf[0] = s->sense;

    s->ti_buf[1] = 0;

    if (s->dma) {

        espdma_memory_write(s->dma_opaque, s->ti_buf, 2);

        s->rregs[4] = STAT_IN | STAT_TC | STAT_ST;

        s->rregs[5] = INTR_BS | INTR_FC;

        s->rregs[6] = SEQ_CD;

    } else {

        s->ti_size = 2;

        s->ti_rptr = 0;

        s->ti_wptr = 0;

        s->rregs[7] = 2;

    }

    espdma_raise_irq(s->dma_opaque);

}

static void esp_dma_done(ESPState *s)

{

    s->rregs[4] |= STAT_IN | STAT_TC;

    s->rregs[5] = INTR_BS;

    s->rregs[6] = 0;

    s->rregs[7] = 0;

    s->rregs[0] = 0;

    s->rregs[1] = 0;

    espdma_raise_irq(s->dma_opaque);

}

static void esp_do_dma(ESPState *s)

{

    uint32_t len;

    int to_device;

    to_device = (s->ti_size < 0);

    len = s->dma_left;

    if (s->do_cmd) {

        DPRINTF("command len %d + %d\n", s->cmdlen, len);

        espdma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len);

        s->ti_size = 0;

        s->cmdlen = 0;

        s->do_cmd = 0;

        do_cmd(s, s->cmdbuf);

        return;

    }

    if (s->async_len == 0) {

        /* Defer until data is available.  */

        return;

    }

    if (len > s->async_len) {

        len = s->async_len;

    }

    if (to_device) {

        espdma_memory_read(s->dma_opaque, s->async_buf, len);

    } else {

        espdma_memory_write(s->dma_opaque, s->async_buf, len);

    }

    s->dma_left -= len;

    s->async_buf += len;

    s->async_len -= len;

    if (to_device)

        s->ti_size += len;

    else

        s->ti_size -= len;

    if (s->async_len == 0) {

        if (to_device) {

            // ti_size is negative

            scsi_write_data(s->current_dev, 0);

        } else {

            scsi_read_data(s->current_dev, 0);

            /* If there is still data to be read from the device then

               complete the DMA operation immeriately.  Otherwise defer

               until the scsi layer has completed.  */

            if (s->dma_left == 0 && s->ti_size > 0) {

                esp_dma_done(s);

            }

        }

    } else {

        /* Partially filled a scsi buffer. Complete immediately.  */

        esp_dma_done(s);

    }

}

static void esp_command_complete(void *opaque, int reason, uint32_t tag,

                                 uint32_t arg)

{

    ESPState *s = (ESPState *)opaque;

    if (reason == SCSI_REASON_DONE) {

        DPRINTF("SCSI Command complete\n");

        if (s->ti_size != 0)

            DPRINTF("SCSI command completed unexpectedly\n");

        s->ti_size = 0;

        s->dma_left = 0;

        s->async_len = 0;

        if (arg)

            DPRINTF("Command failed\n");

        s->sense = arg;

        s->rregs[4] = STAT_ST;

        esp_dma_done(s);

        s->current_dev = NULL;

    } else {

        DPRINTF("transfer %d/%d\n", s->dma_left, s->ti_size);

        s->async_len = arg;

        s->async_buf = scsi_get_buf(s->current_dev, 0);

        if (s->dma_left) {

            esp_do_dma(s);

        } else if (s->dma_counter != 0 && s->ti_size <= 0) {

            /* If this was the last part of a DMA transfer then the

               completion interrupt is deferred to here.  */

            esp_dma_done(s);

        }

    }

}

static void handle_ti(ESPState *s)

{

    uint32_t dmalen, minlen;

    dmalen = s->rregs[0] | (s->rregs[1] << 8);

    if (dmalen==0) {

      dmalen=0x10000;

    }

    s->dma_counter = dmalen;

    if (s->do_cmd)

        minlen = (dmalen < 32) ? dmalen : 32;

    else if (s->ti_size < 0)

        minlen = (dmalen < -s->ti_size) ? dmalen : -s->ti_size;

    else

        minlen = (dmalen < s->ti_size) ? dmalen : s->ti_size;

    DPRINTF("Transfer Information len %d\n", minlen);

    if (s->dma) {

        s->dma_left = minlen;

        s->rregs[4] &= ~STAT_TC;

        esp_do_dma(s);

    } else if (s->do_cmd) {

        DPRINTF("command len %d\n", s->cmdlen);

        s->ti_size = 0;

        s->cmdlen = 0;

        s->do_cmd = 0;

        do_cmd(s, s->cmdbuf);

        return;

    }

}

void esp_reset(void *opaque)

{

    ESPState *s = opaque;

    memset(s->rregs, 0, ESP_MAXREG);

    memset(s->wregs, 0, ESP_MAXREG);

    s->rregs[0x0e] = 0x4; // Indicate fas100a

    s->ti_size = 0;

    s->ti_rptr = 0;

    s->ti_wptr = 0;

    s->dma = 0;

    s->do_cmd = 0;

}

static uint32_t esp_mem_readb(void *opaque, target_phys_addr_t addr)

{

    ESPState *s = opaque;

    uint32_t saddr;

    saddr = (addr & ESP_MAXREG) >> 2;

    DPRINTF("read reg[%d]: 0x%2.2x\n", saddr, s->rregs[saddr]);

    switch (saddr) {

    case 2:

        // FIFO

        if (s->ti_size > 0) {

            s->ti_size--;

            if ((s->rregs[4] & 6) == 0) {

                /* Data in/out.  */

                fprintf(stderr, "esp: PIO data read not implemented\n");

                s->rregs[2] = 0;

            } else {

                s->rregs[2] = s->ti_buf[s->ti_rptr++];

            }

            espdma_raise_irq(s->dma_opaque);

        }

        if (s->ti_size == 0) {

            s->ti_rptr = 0;

            s->ti_wptr = 0;

        }

        break;

    case 5:

        // interrupt

        // Clear interrupt/error status bits

        s->rregs[4] &= ~(STAT_IN | STAT_GE | STAT_PE);

        espdma_clear_irq(s->dma_opaque);

        break;

    default:

        break;

    }

    return s->rregs[saddr];

}

static void esp_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)

{

    ESPState *s = opaque;

    uint32_t saddr;

    saddr = (addr & ESP_MAXREG) >> 2;

    DPRINTF("write reg[%d]: 0x%2.2x -> 0x%2.2x\n", saddr, s->wregs[saddr], val);

    switch (saddr) {

    case 0:

    case 1:

        s->rregs[4] &= ~STAT_TC;

        break;

    case 2:

        // FIFO

        if (s->do_cmd) {

            s->cmdbuf[s->cmdlen++] = val & 0xff;

        } else if ((s->rregs[4] & 6) == 0) {

            uint8_t buf;

            buf = val & 0xff;

            s->ti_size--;

            fprintf(stderr, "esp: PIO data write not implemented\n");

        } else {

            s->ti_size++;

            s->ti_buf[s->ti_wptr++] = val & 0xff;

        }

        break;

    case 3:

        s->rregs[saddr] = val;

        // Command

        if (val & 0x80) {

            s->dma = 1;

            /* Reload DMA counter.  */

            s->rregs[0] = s->wregs[0];

            s->rregs[1] = s->wregs[1];

        } else {

            s->dma = 0;

        }

        switch(val & 0x7f) {

        case 0:

            DPRINTF("NOP (%2.2x)\n", val);

            break;

        case 1:

            DPRINTF("Flush FIFO (%2.2x)\n", val);

            //s->ti_size = 0;

            s->rregs[5] = INTR_FC;

            s->rregs[6] = 0;

            break;

        case 2:

            DPRINTF("Chip reset (%2.2x)\n", val);

            esp_reset(s);

            break;

        case 3:

            DPRINTF("Bus reset (%2.2x)\n", val);

            s->rregs[5] = INTR_RST;

            if (!(s->wregs[8] & 0x40)) {

                espdma_raise_irq(s->dma_opaque);

            }

            break;

        case 0x10:

            handle_ti(s);

            break;

        case 0x11:

            DPRINTF("Initiator Command Complete Sequence (%2.2x)\n", val);

            write_response(s);

            break;

        case 0x12:

            DPRINTF("Message Accepted (%2.2x)\n", val);

            write_response(s);

            s->rregs[5] = INTR_DC;

            s->rregs[6] = 0;

            break;

        case 0x1a:

            DPRINTF("Set ATN (%2.2x)\n", val);

            break;

        case 0x42:

            DPRINTF("Set ATN (%2.2x)\n", val);

            handle_satn(s);

            break;

        case 0x43:

            DPRINTF("Set ATN & stop (%2.2x)\n", val);

            handle_satn_stop(s);

            break;

        default:

            DPRINTF("Unhandled ESP command (%2.2x)\n", val);

            break;

        }

        break;

    case 4 ... 7:

        break;

    case 8:

        s->rregs[saddr] = val;

        break;

    case 9 ... 10:

        break;

    case 11:

        s->rregs[saddr] = val & 0x15;

        break;

    case 12 ... 15:

        s->rregs[saddr] = val;

        break;

    default:

        break;

    }

    s->wregs[saddr] = val;

}

static CPUReadMemoryFunc *esp_mem_read[3] = {

    esp_mem_readb,

    esp_mem_readb,

    esp_mem_readb,

};

static CPUWriteMemoryFunc *esp_mem_write[3] = {

    esp_mem_writeb,

    esp_mem_writeb,

    esp_mem_writeb,

};

static void esp_save(QEMUFile *f, void *opaque)

{

    ESPState *s = opaque;

    qemu_put_buffer(f, s->rregs, ESP_MAXREG);

    qemu_put_buffer(f, s->wregs, ESP_MAXREG);

    qemu_put_be32s(f, &s->ti_size);

    qemu_put_be32s(f, &s->ti_rptr);

    qemu_put_be32s(f, &s->ti_wptr);

    qemu_put_buffer(f, s->ti_buf, TI_BUFSZ);

    qemu_put_be32s(f, &s->dma);

}

static int esp_load(QEMUFile *f, void *opaque, int version_id)

{

    ESPState *s = opaque;

    if (version_id != 2)

        return -EINVAL; // Cannot emulate 1

    qemu_get_buffer(f, s->rregs, ESP_MAXREG);

    qemu_get_buffer(f, s->wregs, ESP_MAXREG);

    qemu_get_be32s(f, &s->ti_size);

    qemu_get_be32s(f, &s->ti_rptr);

    qemu_get_be32s(f, &s->ti_wptr);

    qemu_get_buffer(f, s->ti_buf, TI_BUFSZ);

    qemu_get_be32s(f, &s->dma);

    return 0;

}

void *esp_init(BlockDriverState **bd, uint32_t espaddr, void *dma_opaque)

{

    ESPState *s;

    int esp_io_memory;

    int i;

    s = qemu_mallocz(sizeof(ESPState));

    if (!s)

        return NULL;

    s->bd = bd;

    s->dma_opaque = dma_opaque;

    esp_io_memory = cpu_register_io_memory(0, esp_mem_read, esp_mem_write, s);

    cpu_register_physical_memory(espaddr, ESP_MAXREG*4, esp_io_memory);

    esp_reset(s);

    register_savevm("esp", espaddr, 2, esp_save, esp_load, s);

    qemu_register_reset(esp_reset, s);

    for (i = 0; i < MAX_DISKS; i++) {

        if (bs_table[i]) {

            /* Command queueing is not implemented.  */

            s->scsi_dev[i] =

                scsi_disk_init(bs_table[i], 0, esp_command_complete, s);

        }

    }

    return s;

}