/*

 * 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 "hw.h"

#include "scsi-disk.h"

#include "scsi.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...) do {} while (0)

#endif

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

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

#define ESP_REGS 16

#define TI_BUFSZ 16

typedef struct ESPState ESPState;

struct ESPState {

    uint32_t it_shift;

    qemu_irq irq;

    uint8_t rregs[ESP_REGS];

    uint8_t wregs[ESP_REGS];

    int32_t ti_size;

    uint32_t ti_rptr, ti_wptr;

    uint8_t ti_buf[TI_BUFSZ];

    uint32_t sense;

    uint32_t dma;

    SCSIDevice *scsi_dev[ESP_MAX_DEVS];

    SCSIDevice *current_dev;

    uint8_t cmdbuf[TI_BUFSZ];

    uint32_t cmdlen;

    uint32_t 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;

    espdma_memory_read_write dma_memory_read;

    espdma_memory_read_write dma_memory_write;

    void *dma_opaque;

};

#define ESP_TCLO   0x0

#define ESP_TCMID  0x1

#define ESP_FIFO   0x2

#define ESP_CMD    0x3

#define ESP_RSTAT  0x4

#define ESP_WBUSID 0x4

#define ESP_RINTR  0x5

#define ESP_WSEL   0x5

#define ESP_RSEQ   0x6

#define ESP_WSYNTP 0x6

#define ESP_RFLAGS 0x7

#define ESP_WSYNO  0x7

#define ESP_CFG1   0x8

#define ESP_RRES1  0x9

#define ESP_WCCF   0x9

#define ESP_RRES2  0xa

#define ESP_WTEST  0xa

#define ESP_CFG2   0xb

#define ESP_CFG3   0xc

#define ESP_RES3   0xd

#define ESP_TCHI   0xe

#define ESP_RES4   0xf

#define CMD_DMA 0x80

#define CMD_CMD 0x7f

#define CMD_NOP      0x00

#define CMD_FLUSH    0x01

#define CMD_RESET    0x02

#define CMD_BUSRESET 0x03

#define CMD_TI       0x10

#define CMD_ICCS     0x11

#define CMD_MSGACC   0x12

#define CMD_SATN     0x1a

#define CMD_SELATN   0x42

#define CMD_SELATNS  0x43

#define CMD_ENSEL    0x44

#define STAT_DO 0x00

#define STAT_DI 0x01

#define STAT_CD 0x02

#define STAT_ST 0x03

#define STAT_MO 0x06

#define STAT_MI 0x07

#define STAT_PIO_MASK 0x06

#define STAT_TC 0x10

#define STAT_PE 0x20

#define STAT_GE 0x40

#define STAT_INT 0x80

#define BUSID_DID 0x07

#define INTR_FC 0x08

#define INTR_BS 0x10

#define INTR_DC 0x20

#define INTR_RST 0x80

#define SEQ_0 0x0

#define SEQ_CD 0x4

#define CFG1_RESREPT 0x40

#define TCHI_FAS100A 0x4

static void esp_raise_irq(ESPState *s)

{

    if (!(s->rregs[ESP_RSTAT] & STAT_INT)) {

        s->rregs[ESP_RSTAT] |= STAT_INT;

        qemu_irq_raise(s->irq);

    }

}

static void esp_lower_irq(ESPState *s)

{

    if (s->rregs[ESP_RSTAT] & STAT_INT) {

        s->rregs[ESP_RSTAT] &= ~STAT_INT;

        qemu_irq_lower(s->irq);

    }

}

static uint32_t get_cmd(ESPState *s, uint8_t *buf)

{

    uint32_t dmalen;

    int target;

    target = s->wregs[ESP_WBUSID] & BUSID_DID;

    if (s->dma) {

        dmalen = s->rregs[ESP_TCLO] | (s->rregs[ESP_TCMID] << 8);

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

    } else {

        dmalen = s->ti_size;

        memcpy(buf, s->ti_buf, dmalen);

        buf[0] = 0;

    }

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

    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.  */

        s->current_dev->cancel_io(s->current_dev, 0);

        s->async_len = 0;

    }

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

        // No such drive

        s->rregs[ESP_RSTAT] = 0;

        s->rregs[ESP_RINTR] = INTR_DC;

        s->rregs[ESP_RSEQ] = SEQ_0;

        esp_raise_irq(s);

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

    s->ti_size = datalen;

    if (datalen != 0) {

        s->rregs[ESP_RSTAT] = STAT_TC;

        s->dma_left = 0;

        s->dma_counter = 0;

        if (datalen > 0) {

            s->rregs[ESP_RSTAT] |= STAT_DI;

            s->current_dev->read_data(s->current_dev, 0);

        } else {

            s->rregs[ESP_RSTAT] |= STAT_DO;

            s->current_dev->write_data(s->current_dev, 0);

        }

    }

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

    s->rregs[ESP_RSEQ] = SEQ_CD;

    esp_raise_irq(s);

}

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[ESP_RSTAT] = STAT_TC | STAT_CD;

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

        s->rregs[ESP_RSEQ] = SEQ_CD;

        esp_raise_irq(s);

    }

}

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) {

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

        s->rregs[ESP_RSTAT] = STAT_TC | STAT_ST;

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

        s->rregs[ESP_RSEQ] = SEQ_CD;

    } else {

        s->ti_size = 2;

        s->ti_rptr = 0;

        s->ti_wptr = 0;

        s->rregs[ESP_RFLAGS] = 2;

    }

    esp_raise_irq(s);

}

static void esp_dma_done(ESPState *s)

{

    s->rregs[ESP_RSTAT] |= STAT_TC;

    s->rregs[ESP_RINTR] = INTR_BS;

    s->rregs[ESP_RSEQ] = 0;

    s->rregs[ESP_RFLAGS] = 0;

    s->rregs[ESP_TCLO] = 0;

    s->rregs[ESP_TCMID] = 0;

    esp_raise_irq(s);

}

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);

        s->dma_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) {

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

    } else {

        s->dma_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

            s->current_dev->write_data(s->current_dev, 0);

        } else {

            s->current_dev->read_data(s->current_dev, 0);

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

               complete the DMA operation immediately.  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[ESP_RSTAT] = 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 = s->current_dev->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[ESP_TCLO] | (s->rregs[ESP_TCMID] << 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[ESP_RSTAT] &= ~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;

    }

}

static void esp_reset(void *opaque)

{

    ESPState *s = opaque;

    esp_lower_irq(s);

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

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

    s->rregs[ESP_TCHI] = TCHI_FAS100A; // Indicate fas100a

    s->ti_size = 0;

    s->ti_rptr = 0;

    s->ti_wptr = 0;

    s->dma = 0;

    s->do_cmd = 0;

    s->rregs[ESP_CFG1] = 7;

}

static void parent_esp_reset(void *opaque, int irq, int level)

{

    if (level)

        esp_reset(opaque);

}

static uint32_t esp_mem_readb(void *opaque, target_phys_addr_t addr)

{

    ESPState *s = opaque;

    uint32_t saddr;

    saddr = addr >> s->it_shift;

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

    switch (saddr) {

    case ESP_FIFO:

        if (s->ti_size > 0) {

            s->ti_size--;

            if ((s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) {

                /* Data out.  */

                ESP_ERROR("PIO data read not implemented\n");

                s->rregs[ESP_FIFO] = 0;

            } else {

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

            }

            esp_raise_irq(s);

        }

        if (s->ti_size == 0) {

            s->ti_rptr = 0;

            s->ti_wptr = 0;

        }

        break;

    case ESP_RINTR:

        // Clear interrupt/error status bits

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

        esp_lower_irq(s);

        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 >> s->it_shift;

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

            val);

    switch (saddr) {

    case ESP_TCLO:

    case ESP_TCMID:

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

        break;

    case ESP_FIFO:

        if (s->do_cmd) {

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

        } else if (s->ti_size == TI_BUFSZ - 1) {

            ESP_ERROR("fifo overrun\n");

        } else {

            s->ti_size++;

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

        }

        break;

    case ESP_CMD:

        s->rregs[saddr] = val;

        if (val & CMD_DMA) {

            s->dma = 1;

            /* Reload DMA counter.  */

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

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

        } else {

            s->dma = 0;

        }

        switch(val & CMD_CMD) {

        case CMD_NOP:

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

            break;

        case CMD_FLUSH:

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

            //s->ti_size = 0;

            s->rregs[ESP_RINTR] = INTR_FC;

            s->rregs[ESP_RSEQ] = 0;

            s->rregs[ESP_RFLAGS] = 0;

            break;

        case CMD_RESET:

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

            esp_reset(s);

            break;

        case CMD_BUSRESET:

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

            s->rregs[ESP_RINTR] = INTR_RST;

            if (!(s->wregs[ESP_CFG1] & CFG1_RESREPT)) {

                esp_raise_irq(s);

            }

            break;

        case CMD_TI:

            handle_ti(s);

            break;

        case CMD_ICCS:

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

            write_response(s);

            s->rregs[ESP_RINTR] = INTR_FC;

            s->rregs[ESP_RSTAT] |= STAT_MI;

            break;

        case CMD_MSGACC:

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

            write_response(s);

            s->rregs[ESP_RINTR] = INTR_DC;

            s->rregs[ESP_RSEQ] = 0;

            break;