/* 
 * Arm PrimeCell PL181 MultiMedia Card Interface
 *
 * Copyright (c) 2007 CodeSourcery.
 * Written by Paul Brook
 *
 * This code is licenced under the GPL.
 */

#include "vl.h"
#include "sd.h"

//#define DEBUG_PL181 1

#ifdef DEBUG_PL181
#define DPRINTF(fmt, args...) \
do { printf("pl181: " fmt , ##args); } while (0)
#else
#define DPRINTF(fmt, args...) do {} while(0)
#endif

#define PL181_FIFO_LEN 16

typedef struct {
    SDState *card;
    uint32_t base;
    uint32_t clock;
    uint32_t power;
    uint32_t cmdarg;
    uint32_t cmd;
    uint32_t datatimer;
    uint32_t datalength;
    uint32_t respcmd;
    uint32_t response[4];
    uint32_t datactrl;
    uint32_t datacnt;
    uint32_t status;
    uint32_t mask[2];
    uint32_t fifocnt;
    int fifo_pos;
    int fifo_len;
    uint32_t fifo[PL181_FIFO_LEN];
    qemu_irq irq[2];
} pl181_state;

#define PL181_CMD_INDEX     0x3f
#define PL181_CMD_RESPONSE  (1 << 6)
#define PL181_CMD_LONGRESP  (1 << 7)
#define PL181_CMD_INTERRUPT (1 << 8)
#define PL181_CMD_PENDING   (1 << 9)
#define PL181_CMD_ENABLE    (1 << 10)

#define PL181_DATA_ENABLE             (1 << 0)
#define PL181_DATA_DIRECTION          (1 << 1)
#define PL181_DATA_MODE               (1 << 2)
#define PL181_DATA_DMAENABLE          (1 << 3)

#define PL181_STATUS_CMDCRCFAIL       (1 << 0)
#define PL181_STATUS_DATACRCFAIL      (1 << 1)
#define PL181_STATUS_CMDTIMEOUT       (1 << 2)
#define PL181_STATUS_DATATIMEOUT      (1 << 3)
#define PL181_STATUS_TXUNDERRUN       (1 << 4)
#define PL181_STATUS_RXOVERRUN        (1 << 5)
#define PL181_STATUS_CMDRESPEND       (1 << 6)
#define PL181_STATUS_CMDSENT          (1 << 7)
#define PL181_STATUS_DATAEND          (1 << 8)
#define PL181_STATUS_DATABLOCKEND     (1 << 10)
#define PL181_STATUS_CMDACTIVE        (1 << 11)
#define PL181_STATUS_TXACTIVE         (1 << 12)
#define PL181_STATUS_RXACTIVE         (1 << 13)
#define PL181_STATUS_TXFIFOHALFEMPTY  (1 << 14)
#define PL181_STATUS_RXFIFOHALFFULL   (1 << 15)
#define PL181_STATUS_TXFIFOFULL       (1 << 16)
#define PL181_STATUS_RXFIFOFULL       (1 << 17)
#define PL181_STATUS_TXFIFOEMPTY      (1 << 18)
#define PL181_STATUS_RXFIFOEMPTY      (1 << 19)
#define PL181_STATUS_TXDATAAVLBL      (1 << 20)
#define PL181_STATUS_RXDATAAVLBL      (1 << 21)

#define PL181_STATUS_TX_FIFO (PL181_STATUS_TXACTIVE \
                             |PL181_STATUS_TXFIFOHALFEMPTY \
                             |PL181_STATUS_TXFIFOFULL \
                             |PL181_STATUS_TXFIFOEMPTY \
                             |PL181_STATUS_TXDATAAVLBL)
#define PL181_STATUS_RX_FIFO (PL181_STATUS_RXACTIVE \
                             |PL181_STATUS_RXFIFOHALFFULL \
                             |PL181_STATUS_RXFIFOFULL \
                             |PL181_STATUS_RXFIFOEMPTY \
                             |PL181_STATUS_RXDATAAVLBL)

static const unsigned char pl181_id[] =
{ 0x81, 0x11, 0x04, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };

static void pl181_update(pl181_state *s)
{
    int i;
    for (i = 0; i < 2; i++) {
        qemu_set_irq(s->irq[i], (s->status & s->mask[i]) != 0);
    }
}

static void pl181_fifo_push(pl181_state *s, uint32_t value)
{
    int n;

    if (s->fifo_len == PL181_FIFO_LEN) {
        fprintf(stderr, "pl181: FIFO overflow\n");
        return;
    }
    n = (s->fifo_pos + s->fifo_len) & (PL181_FIFO_LEN - 1);
    s->fifo_len++;
    s->fifo[n] = value;
    DPRINTF("FIFO push %08x\n", (int)value);
}

static uint32_t pl181_fifo_pop(pl181_state *s)
{
    uint32_t value;

    if (s->fifo_len == 0) {
        fprintf(stderr, "pl181: FIFO underflow\n");
        return 0;
    }
    value = s->fifo[s->fifo_pos];
    s->fifo_len--;
    s->fifo_pos = (s->fifo_pos + 1) & (PL181_FIFO_LEN - 1);
    DPRINTF("FIFO pop %08x\n", (int)value);
    return value;
}

static void pl181_send_command(pl181_state *s)
{
    struct sd_request_s request;
    uint8_t response[16];
    int rlen;

    request.cmd = s->cmd & PL181_CMD_INDEX;
    request.arg = s->cmdarg;
    DPRINTF("Command %d %08x\n", request.cmd, request.arg);
    rlen = sd_do_command(s->card, &request, response);
    if (rlen < 0)
        goto error;
    if (s->cmd & PL181_CMD_RESPONSE) {
#define RWORD(n) ((response[n] << 24) | (response[n + 1] << 16) \
                  | (response[n + 2] << 8) | response[n + 3])
        if (rlen == 0 || (rlen == 4 && (s->cmd & PL181_CMD_LONGRESP)))
            goto error;
        if (rlen != 4 && rlen != 16)
            goto error;
        s->response[0] = RWORD(0);
        if (rlen == 4) {
            s->response[1] = s->response[2] = s->response[3] = 0;
        } else {
            s->response[1] = RWORD(4);
            s->response[2] = RWORD(8);
            s->response[3] = RWORD(12) & ~1;
        }
        DPRINTF("Response recieved\n");
        s->status |= PL181_STATUS_CMDRESPEND;
#undef RWORD
    } else {
        DPRINTF("Command sent\n");
        s->status |= PL181_STATUS_CMDSENT;
    }
    return;

error:
    DPRINTF("Timeout\n");
    s->status |= PL181_STATUS_CMDTIMEOUT;
}

/* Transfer data between teh card and the FIFO.  This is complicated by
   the FIFO holding 32-bit words and the card taking data in single byte
   chunks.  FIFO bytes are transferred in little-endian order.  */
   
static void pl181_fifo_run(pl181_state *s)
{
    uint32_t bits;
    uint32_t value;
    int n;
    int limit;
    int is_read;

    is_read = (s->datactrl & PL181_DATA_DIRECTION) != 0;
    if (s->datacnt != 0 && (!is_read || sd_data_ready(s->card))) {
        limit = is_read ? PL181_FIFO_LEN : 0;
        n = 0;
        value = 0;
        while (s->datacnt && s->fifo_len != limit) {
            if (is_read) {
                value |= (uint32_t)sd_read_data(s->card) << (n * 8);
                n++;
                if (n == 4) {
                    pl181_fifo_push(s, value);
                    value = 0;
                    n = 0;
                }
            } else {
                if (n == 0) {
                    value = pl181_fifo_pop(s);
                    n = 4;
                }
                sd_write_data(s->card, value & 0xff);
                value >>= 8;
                n--;
            }
            s->datacnt--;
        }
        if (n && is_read) {
            pl181_fifo_push(s, value);
        }
    }
    s->status &= ~(PL181_STATUS_RX_FIFO | PL181_STATUS_TX_FIFO);
    if (s->datacnt == 0) {
        s->status |= PL181_STATUS_DATAEND;
        /* HACK: */
        s->status |= PL181_STATUS_DATABLOCKEND;
        DPRINTF("Transfer Complete\n");
    }
    if (s->datacnt == 0 && s->fifocnt == 0) {
        s->datactrl &= ~PL181_DATA_ENABLE;
        DPRINTF("Data engine idle\n");
    } else {
        /* Update FIFO bits.  */
        bits = PL181_STATUS_TXACTIVE | PL181_STATUS_RXACTIVE;
        if (s->fifo_len == 0) {
            bits |= PL181_STATUS_TXFIFOEMPTY;
            bits |= PL181_STATUS_RXFIFOEMPTY;
        } else {
            bits |= PL181_STATUS_TXDATAAVLBL;
            bits |= PL181_STATUS_RXDATAAVLBL;
        }
        if (s->fifo_len == 16) {
            bits |= PL181_STATUS_TXFIFOFULL;
            bits |= PL181_STATUS_RXFIFOFULL;
        }
        if (s->fifo_len <= 8) {
            bits |= PL181_STATUS_TXFIFOHALFEMPTY;
        }
        if (s->fifo_len >= 8) {
            bits |= PL181_STATUS_RXFIFOHALFFULL;
        }
        if (s->datactrl & PL181_DATA_DIRECTION) {
            bits &= PL181_STATUS_RX_FIFO;
        } else {
            bits &= PL181_STATUS_TX_FIFO;
        }
        s->status |= bits;
    }
}

static uint32_t pl181_read(void *opaque, target_phys_addr_t offset)
{
    pl181_state *s = (pl181_state *)opaque;

    offset -= s->base;
    if (offset >= 0xfe0 && offset < 0x1000) {
        return pl181_id[(offset - 0xfe0) >> 2];
    }
    switch (offset) {
    case 0x00: /* Power */
        return s->power;
    case 0x04: /* Clock */
        return s->clock;
    case 0x08: /* Argument */
        return s->cmdarg;
    case 0x0c: /* Command */
        return s->cmd;
    case 0x10: /* RespCmd */
        return s->respcmd;
    case 0x14: /* Response0 */
        return s->response[0];
    case 0x18: /* Response1 */
        return s->response[1];
    case 0x1c: /* Response2 */
        return s->response[2];
    case 0x20: /* Response3 */
        return s->response[3];
    case 0x24: /* DataTimer */
        return s->datatimer;
    case 0x28: /* DataLength */
        return s->datalength;
    case 0x2c: /* DataCtrl */
        return s->datactrl;
    case 0x30: /* DataCnt */
        return s->datacnt;
    case 0x34: /* Status */
        return s->status;
    case 0x3c: /* Mask0 */
        return s->mask[0];
    case 0x40: /* Mask1 */
        return s->mask[1];
    case 0x48: /* FifoCnt */
        return s->fifocnt;
    case 0x80: case 0x84: case 0x88: case 0x8c: /* FifoData */
    case 0x90: case 0x94: case 0x98: case 0x9c:
    case 0xa0: case 0xa4: case 0xa8: case 0xac:
    case 0xb0: case 0xb4: case 0xb8: case 0xbc:
        if (s->fifocnt == 0) {
            fprintf(stderr, "pl181: Unexpected FIFO read\n");
            return 0;
        } else {
            uint32_t value;
            s->fifocnt--;
            value = pl181_fifo_pop(s);
            pl181_fifo_run(s);
            pl181_update(s);
            return value;
        }
    default:
        cpu_abort (cpu_single_env, "pl181_read: Bad offset %x\n", offset);
        return 0;
    }
}

static void pl181_write(void *opaque, target_phys_addr_t offset,
                          uint32_t value)
{
    pl181_state *s = (pl181_state *)opaque;

    offset -= s->base;
    switch (offset) {
    case 0x00: /* Power */
        s->power = value & 0xff;
        break;
    case 0x04: /* Clock */
        s->clock = value & 0xff;
        break;
    case 0x08: /* Argument */
        s->cmdarg = value;
        break;
    case 0x0c: /* Command */
        s->cmd = value;
        if (s->cmd & PL181_CMD_ENABLE) {
            if (s->cmd & PL181_CMD_INTERRUPT) {
                fprintf(stderr, "pl181: Interrupt mode not implemented\n");
                abort();
            } if (s->cmd & PL181_CMD_PENDING) {
                fprintf(stderr, "pl181: Pending commands not implemented\n");
                abort();
            } else {
                pl181_send_command(s);
                pl181_fifo_run(s);
            }
            /* The command has completed one way or the other.  */
            s->cmd &= ~PL181_CMD_ENABLE;
        }
        break;
    case 0x24: /* DataTimer */
        s->datatimer = value;
        break;
    case 0x28: /* DataLength */
        s->datalength = value & 0xffff;
        break;
    case 0x2c: /* DataCtrl */
        s->datactrl = value & 0xff;
        if (value & PL181_DATA_ENABLE) {
            s->datacnt = s->datalength;
            s->fifocnt = (s->datalength + 3) >> 2;
            pl181_fifo_run(s);
        }
        break;
    case 0x38: /* Clear */
        s->status &= ~(value & 0x7ff);
        break;
    case 0x3c: /* Mask0 */
        s->mask[0] = value;
        break;
    case 0x40: /* Mask1 */
        s->mask[1] = value;
        break;
    case 0x80: case 0x84: case 0x88: case 0x8c: /* FifoData */
    case 0x90: case 0x94: case 0x98: case 0x9c:
    case 0xa0: case 0xa4: case 0xa8: case 0xac:
    case 0xb0: case 0xb4: case 0xb8: case 0xbc:
        if (s->fifocnt == 0) {
            fprintf(stderr, "pl181: Unexpected FIFO write\n");
        } else {
            s->fifocnt--;
            pl181_fifo_push(s, value);
            pl181_fifo_run(s);
        }
        break;
    default:
        cpu_abort (cpu_single_env, "pl181_write: Bad offset %x\n", offset);
    }
    pl181_update(s);
}

static CPUReadMemoryFunc *pl181_readfn[] = {
   pl181_read,
   pl181_read,
   pl181_read
};

static CPUWriteMemoryFunc *pl181_writefn[] = {
   pl181_write,
   pl181_write,
   pl181_write
};

static void pl181_reset(void *opaque)
{
    pl181_state *s = (pl181_state *)opaque;

    s->power = 0;
    s->cmdarg = 0;
    s->cmd = 0;
    s->datatimer = 0;
    s->datalength = 0;
    s->respcmd = 0;
    s->response[0] = 0;
    s->response[1] = 0;
    s->response[2] = 0;
    s->response[3] = 0;
    s->datatimer = 0;
    s->datalength = 0;
    s->datactrl = 0;
    s->datacnt = 0;
    s->status = 0;
    s->mask[0] = 0;
    s->mask[1] = 0;
    s->fifocnt = 0;
}

void pl181_init(uint32_t base, BlockDriverState *bd,
                qemu_irq irq0, qemu_irq irq1)
{
    int iomemtype;
    pl181_state *s;

    s = (pl181_state *)qemu_mallocz(sizeof(pl181_state));
    iomemtype = cpu_register_io_memory(0, pl181_readfn,
                                       pl181_writefn, s);
    cpu_register_physical_memory(base, 0x00001000, iomemtype);
    s->base = base;
    s->card = sd_init(bd);
    s->irq[0] = irq0;
    s->irq[1] = irq1;
    qemu_register_reset(pl181_reset, s);
    pl181_reset(s);
    /* ??? Save/restore.  */
}