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/*

 * QEMU ESP/NCR53C9x emulation

 *

 * Copyright (c) 2005-2006 Fabrice Bellard

 * Copyright (c) 2012 Herve Poussineau

 *

 * 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 "sysbus.h"

#include "esp.h"

#include "trace.h"

#include "qemu/log.h"

/*

 * 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

 */

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);

        trace_esp_raise_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);

        trace_esp_lower_irq();

    }

}

void esp_dma_enable(ESPState *s, int irq, int level)

{

    if (level) {

        s->dma_enabled = 1;

        trace_esp_dma_enable();

        if (s->dma_cb) {

            s->dma_cb(s);

            s->dma_cb = NULL;

        }

    } else {

        trace_esp_dma_disable();

        s->dma_enabled = 0;

    }

}

void esp_request_cancelled(SCSIRequest *req)

{

    ESPState *s = req->hba_private;

    if (req == s->current_req) {

        scsi_req_unref(s->current_req);

        s->current_req = NULL;

        s->current_dev = NULL;

    }

}

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];

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

        dmalen |= s->rregs[ESP_TCHI] << 16;

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

    } else {

        dmalen = s->ti_size;

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

        buf[0] = buf[2] >> 5;

    }

    trace_esp_get_cmd(dmalen, target);

    s->ti_size = 0;

    s->ti_rptr = 0;

    s->ti_wptr = 0;

    if (s->current_req) {

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

        scsi_req_cancel(s->current_req);

        s->async_len = 0;

    }

    s->current_dev = scsi_device_find(&s->bus, 0, target, 0);

    if (!s->current_dev) {

        // 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;

    }

    return dmalen;

}

static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)

{

    int32_t datalen;

    int lun;

    SCSIDevice *current_lun;

    trace_esp_do_busid_cmd(busid);

    lun = busid & 7;

    current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, lun);

    s->current_req = scsi_req_new(current_lun, 0, lun, buf, s);

    datalen = scsi_req_enqueue(s->current_req);

    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;

        } else {

            s->rregs[ESP_RSTAT] |= STAT_DO;

        }

        scsi_req_continue(s->current_req);

    }

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

    s->rregs[ESP_RSEQ] = SEQ_CD;

    esp_raise_irq(s);

}

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

{

    uint8_t busid = buf[0];

    do_busid_cmd(s, &buf[1], busid);

}

static void handle_satn(ESPState *s)

{

    uint8_t buf[32];

    int len;

    if (s->dma && !s->dma_enabled) {

        s->dma_cb = handle_satn;

        return;

    }

    len = get_cmd(s, buf);

    if (len)

        do_cmd(s, buf);

}

static void handle_s_without_atn(ESPState *s)

{

    uint8_t buf[32];

    int len;

    if (s->dma && !s->dma_enabled) {

        s->dma_cb = handle_s_without_atn;

        return;

    }

    len = get_cmd(s, buf);

    if (len) {

        do_busid_cmd(s, buf, 0);

    }

}

static void handle_satn_stop(ESPState *s)

{

    if (s->dma && !s->dma_enabled) {

        s->dma_cb = handle_satn_stop;

        return;

    }

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

    if (s->cmdlen) {

        trace_esp_handle_satn_stop(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)

{

    trace_esp_write_response(s->status);

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

    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;

    s->rregs[ESP_TCHI] = 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) {

        trace_esp_do_dma(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) {

        scsi_req_continue(s->current_req);

        /* 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 (to_device || s->dma_left != 0 || s->ti_size == 0) {

            return;

        }

    }

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

    esp_dma_done(s);

}

void esp_command_complete(SCSIRequest *req, uint32_t status,

                                 size_t resid)

{

    ESPState *s = req->hba_private;

    trace_esp_command_complete();

    if (s->ti_size != 0) {

        trace_esp_command_complete_unexpected();

    }

    s->ti_size = 0;

    s->dma_left = 0;

    s->async_len = 0;

    if (status) {

        trace_esp_command_complete_fail();

    }

    s->status = status;

    s->rregs[ESP_RSTAT] = STAT_ST;

    esp_dma_done(s);

    if (s->current_req) {

        scsi_req_unref(s->current_req);

        s->current_req = NULL;

        s->current_dev = NULL;

    }

}

void esp_transfer_data(SCSIRequest *req, uint32_t len)

{

    ESPState *s = req->hba_private;

    trace_esp_transfer_data(s->dma_left, s->ti_size);

    s->async_len = len;

    s->async_buf = scsi_req_get_buf(req);

    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;

    if (s->dma && !s->dma_enabled) {

        s->dma_cb = handle_ti;

        return;

    }

    dmalen = s->rregs[ESP_TCLO];

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

    dmalen |= s->rregs[ESP_TCHI] << 16;

    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;

    trace_esp_handle_ti(minlen);

    if (s->dma) {

        s->dma_left = minlen;

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

        esp_do_dma(s);

    } else if (s->do_cmd) {

        trace_esp_handle_ti_cmd(s->cmdlen);

        s->ti_size = 0;

        s->cmdlen = 0;

        s->do_cmd = 0;

        do_cmd(s, s->cmdbuf);

        return;

    }

}

void esp_hard_reset(ESPState *s)

{

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

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

    s->rregs[ESP_TCHI] = s->chip_id;

    s->ti_size = 0;

    s->ti_rptr = 0;

    s->ti_wptr = 0;

    s->dma = 0;

    s->do_cmd = 0;

    s->dma_cb = NULL;

    s->rregs[ESP_CFG1] = 7;

}

static void esp_soft_reset(ESPState *s)

{

    qemu_irq_lower(s->irq);

    esp_hard_reset(s);

}

static void parent_esp_reset(ESPState *s, int irq, int level)

{

    if (level) {

        esp_soft_reset(s);

    }

}

uint64_t esp_reg_read(ESPState *s, uint32_t saddr)

{

    uint32_t old_val;

    trace_esp_mem_readb(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.  */

                qemu_log_mask(LOG_UNIMP,

                              "esp: 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 sequence step, interrupt register and all status bits

           except TC */

        old_val = s->rregs[ESP_RINTR];

        s->rregs[ESP_RINTR] = 0;

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

        s->rregs[ESP_RSEQ] = SEQ_CD;

        esp_lower_irq(s);

        return old_val;

    default:

        break;

    }

    return s->rregs[saddr];

}

void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)

{

    trace_esp_mem_writeb(saddr, s->wregs[saddr], val);

    switch (saddr) {

    case ESP_TCLO:

    case ESP_TCMID:

    case ESP_TCHI:

        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) {

            trace_esp_error_fifo_overrun();

        } 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];

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

        } else {

            s->dma = 0;

        }

        switch(val & CMD_CMD) {

        case CMD_NOP:

            trace_esp_mem_writeb_cmd_nop(val);

            break;

        case CMD_FLUSH:

            trace_esp_mem_writeb_cmd_flush(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:

            trace_esp_mem_writeb_cmd_reset(val);

            esp_soft_reset(s);

            break;

        case CMD_BUSRESET:

            trace_esp_mem_writeb_cmd_bus_reset(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:

            trace_esp_mem_writeb_cmd_iccs(val);

            write_response(s);

            s->rregs[ESP_RINTR] = INTR_FC;

            s->rregs[ESP_RSTAT] |= STAT_MI;

            break;

        case CMD_MSGACC:

            trace_esp_mem_writeb_cmd_msgacc(val);

            s->rregs[ESP_RINTR] = INTR_DC;

            s->rregs[ESP_RSEQ] = 0;

            s->rregs[ESP_RFLAGS] = 0;

            esp_raise_irq(s);

            break;

        case CMD_PAD:

            trace_esp_mem_writeb_cmd_pad(val);

            s->rregs[ESP_RSTAT] = STAT_TC;

            s->rregs[ESP_RINTR] = INTR_FC;

            s->rregs[ESP_RSEQ] = 0;

            break;

        case CMD_SATN:

            trace_esp_mem_writeb_cmd_satn(val);

            break;

        case CMD_RSTATN:

            trace_esp_mem_writeb_cmd_rstatn(val);

            break;

        case CMD_SEL:

            trace_esp_mem_writeb_cmd_sel(val);

            handle_s_without_atn(s);

            break;

        case CMD_SELATN:

            trace_esp_mem_writeb_cmd_selatn(val);

            handle_satn(s);

            break;

        case CMD_SELATNS:

            trace_esp_mem_writeb_cmd_selatns(val);

            handle_satn_stop(s);

            break;

        case CMD_ENSEL:

            trace_esp_mem_writeb_cmd_ensel(val);

            s->rregs[ESP_RINTR] = 0;

            break;

        case CMD_DISSEL:

            trace_esp_mem_writeb_cmd_dissel(val);

            s->rregs[ESP_RINTR] = 0;

            esp_raise_irq(s);

            break;

        default:

            trace_esp_error_unhandled_command(val);

            break;

        }

        break;

    case ESP_WBUSID ... ESP_WSYNO:

        break;

    case ESP_CFG1:

    case ESP_CFG2: case ESP_CFG3:

    case ESP_RES3: case ESP_RES4:

        s->rregs[saddr] = val;

        break;

    case ESP_WCCF ... ESP_WTEST:

        break;

    default:

        trace_esp_error_invalid_write(val, saddr);

        return;

    }

    s->wregs[saddr] = val;

}

static bool esp_mem_accepts(void *opaque, hwaddr addr,

                            unsigned size, bool is_write)

{

    return (size == 1) || (is_write && size == 4);

}

const VMStateDescription vmstate_esp = {

    .name ="esp",

    .version_id = 3,

    .minimum_version_id = 3,

    .minimum_version_id_old = 3,

    .fields      = (VMStateField []) {

        VMSTATE_BUFFER(rregs, ESPState),

        VMSTATE_BUFFER(wregs, ESPState),

        VMSTATE_INT32(ti_size, ESPState),

        VMSTATE_UINT32(ti_rptr, ESPState),

        VMSTATE_UINT32(ti_wptr, ESPState),

        VMSTATE_BUFFER(ti_buf, ESPState),

        VMSTATE_UINT32(status, ESPState),

        VMSTATE_UINT32(dma, ESPState),

        VMSTATE_BUFFER(cmdbuf, ESPState),

        VMSTATE_UINT32(cmdlen, ESPState),

        VMSTATE_UINT32(do_cmd, ESPState),

        VMSTATE_UINT32(dma_left, ESPState),

        VMSTATE_END_OF_LIST()

    }

};

typedef struct {

    SysBusDevice busdev;

    MemoryRegion iomem;

    uint32_t it_shift;

    ESPState esp;

} SysBusESPState;

static void sysbus_esp_mem_write(void *opaque, hwaddr addr,

                                 uint64_t val, unsigned int size)

{

    SysBusESPState *sysbus = opaque;

    uint32_t saddr;

    saddr = addr >> sysbus->it_shift;

    esp_reg_write(&sysbus->esp, saddr, val);

}

static uint64_t sysbus_esp_mem_read(void *opaque, hwaddr addr,

                                    unsigned int size)

{

    SysBusESPState *sysbus = opaque;

    uint32_t saddr;

    saddr = addr >> sysbus->it_shift;

    return esp_reg_read(&sysbus->esp, saddr);

}

static const MemoryRegionOps sysbus_esp_mem_ops = {

    .read = sysbus_esp_mem_read,

    .write = sysbus_esp_mem_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

    .valid.accepts = esp_mem_accepts,

};

void esp_init(hwaddr espaddr, int it_shift,

              ESPDMAMemoryReadWriteFunc dma_memory_read,

              ESPDMAMemoryReadWriteFunc dma_memory_write,

              void *dma_opaque, qemu_irq irq, qemu_irq *reset,

              qemu_irq *dma_enable)

{

    DeviceState *dev;

    SysBusDevice *s;

    SysBusESPState *sysbus;

    ESPState *esp;

    dev = qdev_create(NULL, "esp");

    sysbus = DO_UPCAST(SysBusESPState, busdev.qdev, dev);

    esp = &sysbus->esp;

    esp->dma_memory_read = dma_memory_read;

    esp->dma_memory_write = dma_memory_write;

    esp->dma_opaque = dma_opaque;

    sysbus->it_shift = it_shift;

    /* XXX for now until rc4030 has been changed to use DMA enable signal */

    esp->dma_enabled = 1;

    qdev_init_nofail(dev);

    s = sysbus_from_qdev(dev);

    sysbus_connect_irq(s, 0, irq);

    sysbus_mmio_map(s, 0, espaddr);

    *reset = qdev_get_gpio_in(dev, 0);

    *dma_enable = qdev_get_gpio_in(dev, 1);

}

static const struct SCSIBusInfo esp_scsi_info = {

    .tcq = false,

    .max_target = ESP_MAX_DEVS,

    .max_lun = 7,

    .transfer_data = esp_transfer_data,

    .complete = esp_command_complete,

    .cancel = esp_request_cancelled

};

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

{

    DeviceState *d = opaque;

    SysBusESPState *sysbus = container_of(d, SysBusESPState, busdev.qdev);

    ESPState *s = &sysbus->esp;

    switch (irq) {

    case 0:

        parent_esp_reset(s, irq, level);

        break;

    case 1:

        esp_dma_enable(opaque, irq, level);

        break;

    }

}

static int sysbus_esp_init(SysBusDevice *dev)

{

    SysBusESPState *sysbus = FROM_SYSBUS(SysBusESPState, dev);

    ESPState *s = &sysbus->esp;

    sysbus_init_irq(dev, &s->irq);

    assert(sysbus->it_shift != -1);

    s->chip_id = TCHI_FAS100A;

    memory_region_init_io(&sysbus->iomem, &sysbus_esp_mem_ops, sysbus,

                          "esp", ESP_REGS << sysbus->it_shift);

    sysbus_init_mmio(dev, &sysbus->iomem);

    qdev_init_gpio_in(&dev->qdev, sysbus_esp_gpio_demux, 2);

    scsi_bus_new(&s->bus, &dev->qdev, &esp_scsi_info);

    return scsi_bus_legacy_handle_cmdline(&s->bus);

}

static void sysbus_esp_hard_reset(DeviceState *dev)

{

    SysBusESPState *sysbus = DO_UPCAST(SysBusESPState, busdev.qdev, dev);

    esp_hard_reset(&sysbus->esp);

}

static const VMStateDescription vmstate_sysbus_esp_scsi = {

    .name = "sysbusespscsi",

    .version_id = 0,

    .minimum_version_id = 0,

    .minimum_version_id_old = 0,

    .fields = (VMStateField[]) {

        VMSTATE_STRUCT(esp, SysBusESPState, 0, vmstate_esp, ESPState),

        VMSTATE_END_OF_LIST()

    }

};

static void sysbus_esp_class_init(ObjectClass *klass, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = sysbus_esp_init;

    dc->reset = sysbus_esp_hard_reset;

    dc->vmsd = &vmstate_sysbus_esp_scsi;

}

static const TypeInfo sysbus_esp_info = {

    .name          = "esp",

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(SysBusESPState),

    .class_init    = sysbus_esp_class_init,

};

static void esp_register_types(void)

{

    type_register_static(&sysbus_esp_info);

}

type_init(esp_register_types)