/*

 * ColdFire Fast Ethernet Controller emulation.

 *

 * Copyright (c) 2007 CodeSourcery.

 *

 * This code is licenced under the GPL

 */

#include "hw.h"

#include "net.h"

#include "mcf.h"

/* For crc32 */

#include <zlib.h>

//#define DEBUG_FEC 1

#ifdef DEBUG_FEC

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

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

#else

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

#endif

#define FEC_MAX_FRAME_SIZE 2032

typedef struct {

    qemu_irq *irq;

    VLANClientState *vc;

    uint32_t irq_state;

    uint32_t eir;

    uint32_t eimr;

    int rx_enabled;

    uint32_t rx_descriptor;

    uint32_t tx_descriptor;

    uint32_t ecr;

    uint32_t mmfr;

    uint32_t mscr;

    uint32_t rcr;

    uint32_t tcr;

    uint32_t tfwr;

    uint32_t rfsr;

    uint32_t erdsr;

    uint32_t etdsr;

    uint32_t emrbr;

    uint8_t macaddr[6];

} mcf_fec_state;

#define FEC_INT_HB   0x80000000

#define FEC_INT_BABR 0x40000000

#define FEC_INT_BABT 0x20000000

#define FEC_INT_GRA  0x10000000

#define FEC_INT_TXF  0x08000000

#define FEC_INT_TXB  0x04000000

#define FEC_INT_RXF  0x02000000

#define FEC_INT_RXB  0x01000000

#define FEC_INT_MII  0x00800000

#define FEC_INT_EB   0x00400000

#define FEC_INT_LC   0x00200000

#define FEC_INT_RL   0x00100000

#define FEC_INT_UN   0x00080000

#define FEC_EN      2

#define FEC_RESET   1

/* Map interrupt flags onto IRQ lines.  */

#define FEC_NUM_IRQ 13

static const uint32_t mcf_fec_irq_map[FEC_NUM_IRQ] = {

    FEC_INT_TXF,

    FEC_INT_TXB,

    FEC_INT_UN,

    FEC_INT_RL,

    FEC_INT_RXF,

    FEC_INT_RXB,

    FEC_INT_MII,

    FEC_INT_LC,

    FEC_INT_HB,

    FEC_INT_GRA,

    FEC_INT_EB,

    FEC_INT_BABT,

    FEC_INT_BABR

};

/* Buffer Descriptor.  */

typedef struct {

    uint16_t flags;

    uint16_t length;

    uint32_t data;

} mcf_fec_bd;

#define FEC_BD_R    0x8000

#define FEC_BD_E    0x8000

#define FEC_BD_O1   0x4000

#define FEC_BD_W    0x2000

#define FEC_BD_O2   0x1000

#define FEC_BD_L    0x0800

#define FEC_BD_TC   0x0400

#define FEC_BD_ABC  0x0200

#define FEC_BD_M    0x0100

#define FEC_BD_BC   0x0080

#define FEC_BD_MC   0x0040

#define FEC_BD_LG   0x0020

#define FEC_BD_NO   0x0010

#define FEC_BD_CR   0x0004

#define FEC_BD_OV   0x0002

#define FEC_BD_TR   0x0001

static void mcf_fec_read_bd(mcf_fec_bd *bd, uint32_t addr)

{

    cpu_physical_memory_read(addr, (uint8_t *)bd, sizeof(*bd));

    be16_to_cpus(&bd->flags);

    be16_to_cpus(&bd->length);

    be32_to_cpus(&bd->data);

}

static void mcf_fec_write_bd(mcf_fec_bd *bd, uint32_t addr)

{

    mcf_fec_bd tmp;

    tmp.flags = cpu_to_be16(bd->flags);

    tmp.length = cpu_to_be16(bd->length);

    tmp.data = cpu_to_be32(bd->data);

    cpu_physical_memory_write(addr, (uint8_t *)&tmp, sizeof(tmp));

}

static void mcf_fec_update(mcf_fec_state *s)

{

    uint32_t active;

    uint32_t changed;

    uint32_t mask;

    int i;

    active = s->eir & s->eimr;

    changed = active ^s->irq_state;

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

        mask = mcf_fec_irq_map[i];

        if (changed & mask) {

            DPRINTF("IRQ %d = %d\n", i, (active & mask) != 0);

            qemu_set_irq(s->irq[i], (active & mask) != 0);

        }

    }

    s->irq_state = active;

}

static void mcf_fec_do_tx(mcf_fec_state *s)

{

    uint32_t addr;

    mcf_fec_bd bd;

    int frame_size;

    int len;

    uint8_t frame[FEC_MAX_FRAME_SIZE];

    uint8_t *ptr;

    DPRINTF("do_tx\n");

    ptr = frame;

    frame_size = 0;

    addr = s->tx_descriptor;

    while (1) {

        mcf_fec_read_bd(&bd, addr);

        DPRINTF("tx_bd %x flags %04x len %d data %08x\n",

                addr, bd.flags, bd.length, bd.data);

        if ((bd.flags & FEC_BD_R) == 0) {

            /* Run out of descriptors to transmit.  */

            break;

        }

        len = bd.length;

        if (frame_size + len > FEC_MAX_FRAME_SIZE) {

            len = FEC_MAX_FRAME_SIZE - frame_size;

            s->eir |= FEC_INT_BABT;

        }

        cpu_physical_memory_read(bd.data, ptr, len);

        ptr += len;

        frame_size += len;

        if (bd.flags & FEC_BD_L) {

            /* Last buffer in frame.  */

            DPRINTF("Sending packet\n");

            qemu_send_packet(s->vc, frame, len);

            ptr = frame;

            frame_size = 0;

            s->eir |= FEC_INT_TXF;

        }

        s->eir |= FEC_INT_TXB;

        bd.flags &= ~FEC_BD_R;

        /* Write back the modified descriptor.  */

        mcf_fec_write_bd(&bd, addr);

        /* Advance to the next descriptor.  */

        if ((bd.flags & FEC_BD_W) != 0) {

            addr = s->etdsr;

        } else {

            addr += 8;

        }

    }

    s->tx_descriptor = addr;

}

static void mcf_fec_enable_rx(mcf_fec_state *s)

{

    mcf_fec_bd bd;

    mcf_fec_read_bd(&bd, s->rx_descriptor);

    s->rx_enabled = ((bd.flags & FEC_BD_E) != 0);

    if (!s->rx_enabled)

        DPRINTF("RX buffer full\n");

}

static void mcf_fec_reset(mcf_fec_state *s)

{

    s->eir = 0;

    s->eimr = 0;

    s->rx_enabled = 0;

    s->ecr = 0;

    s->mscr = 0;

    s->rcr = 0x05ee0001;

    s->tcr = 0;

    s->tfwr = 0;

    s->rfsr = 0x500;

}

static uint32_t mcf_fec_read(void *opaque, target_phys_addr_t addr)

{

    mcf_fec_state *s = (mcf_fec_state *)opaque;

    switch (addr & 0x3ff) {

    case 0x004: return s->eir;

    case 0x008: return s->eimr;

    case 0x010: return s->rx_enabled ? (1 << 24) : 0; /* RDAR */

    case 0x014: return 0; /* TDAR */

    case 0x024: return s->ecr;

    case 0x040: return s->mmfr;

    case 0x044: return s->mscr;

    case 0x064: return 0; /* MIBC */

    case 0x084: return s->rcr;

    case 0x0c4: return s->tcr;

    case 0x0e4: /* PALR */

        return (s->macaddr[0] << 24) | (s->macaddr[1] << 16)

              | (s->macaddr[2] << 8) | s->macaddr[3];

        break;

    case 0x0e8: /* PAUR */

        return (s->macaddr[4] << 24) | (s->macaddr[5] << 16) | 0x8808;

    case 0x0ec: return 0x10000; /* OPD */

    case 0x118: return 0;

    case 0x11c: return 0;

    case 0x120: return 0;

    case 0x124: return 0;

    case 0x144: return s->tfwr;

    case 0x14c: return 0x600;

    case 0x150: return s->rfsr;

    case 0x180: return s->erdsr;

    case 0x184: return s->etdsr;

    case 0x188: return s->emrbr;

    default:

        cpu_abort(cpu_single_env, "mcf_fec_read: Bad address 0x%x\n",

                  (int)addr);

        return 0;

    }

}

static void mcf_fec_write(void *opaque, target_phys_addr_t addr, uint32_t value)

{

    mcf_fec_state *s = (mcf_fec_state *)opaque;

    switch (addr & 0x3ff) {

    case 0x004:

        s->eir &= ~value;

        break;

    case 0x008:

        s->eimr = value;

        break;

    case 0x010: /* RDAR */

        if ((s->ecr & FEC_EN) && !s->rx_enabled) {

            DPRINTF("RX enable\n");

            mcf_fec_enable_rx(s);

        }

        break;

    case 0x014: /* TDAR */

        if (s->ecr & FEC_EN) {

            mcf_fec_do_tx(s);

        }

        break;

    case 0x024:

        s->ecr = value;

        if (value & FEC_RESET) {

            DPRINTF("Reset\n");

            mcf_fec_reset(s);

        }

        if ((s->ecr & FEC_EN) == 0) {

            s->rx_enabled = 0;

        }

        break;

    case 0x040:

        /* TODO: Implement MII.  */

        s->mmfr = value;

        break;

    case 0x044:

        s->mscr = value & 0xfe;

        break;

    case 0x064:

        /* TODO: Implement MIB.  */

        break;

    case 0x084:

        s->rcr = value & 0x07ff003f;

        /* TODO: Implement LOOP mode.  */

        break;

    case 0x0c4: /* TCR */

        /* We transmit immediately, so raise GRA immediately.  */

        s->tcr = value;

        if (value & 1)

            s->eir |= FEC_INT_GRA;

        break;

    case 0x0e4: /* PALR */

        s->macaddr[0] = value >> 24;

        s->macaddr[1] = value >> 16;

        s->macaddr[2] = value >> 8;

        s->macaddr[3] = value;

        break;

    case 0x0e8: /* PAUR */

        s->macaddr[4] = value >> 24;

        s->macaddr[5] = value >> 16;

        break;

    case 0x0ec:

        /* OPD */

        break;

    case 0x118:

    case 0x11c:

    case 0x120:

    case 0x124:

        /* TODO: implement MAC hash filtering.  */

        break;

    case 0x144:

        s->tfwr = value & 3;

        break;

    case 0x14c:

        /* FRBR writes ignored.  */

        break;

    case 0x150:

        s->rfsr = (value & 0x3fc) | 0x400;

        break;

    case 0x180:

        s->erdsr = value & ~3;

        s->rx_descriptor = s->erdsr;

        break;

    case 0x184:

        s->etdsr = value & ~3;

        s->tx_descriptor = s->etdsr;

        break;

    case 0x188:

        s->emrbr = value & 0x7f0;

        break;

    default:

        cpu_abort(cpu_single_env, "mcf_fec_write Bad address 0x%x\n",

                  (int)addr);

    }

    mcf_fec_update(s);

}

static int mcf_fec_can_receive(void *opaque)

{

    mcf_fec_state *s = (mcf_fec_state *)opaque;

    return s->rx_enabled;

}

static void mcf_fec_receive(void *opaque, const uint8_t *buf, int size)

{

    mcf_fec_state *s = (mcf_fec_state *)opaque;

    mcf_fec_bd bd;

    uint32_t flags = 0;

    uint32_t addr;

    uint32_t crc;

    uint32_t buf_addr;

    uint8_t *crc_ptr;

    unsigned int buf_len;

    DPRINTF("do_rx len %d\n", size);

    if (!s->rx_enabled) {

        fprintf(stderr, "mcf_fec_receive: Unexpected packet\n");

    }

    /* 4 bytes for the CRC.  */

    size += 4;

    crc = cpu_to_be32(crc32(~0, buf, size));

    crc_ptr = (uint8_t *)&crc;

    /* Huge frames are truncted.  */

    if (size > FEC_MAX_FRAME_SIZE) {

        size = FEC_MAX_FRAME_SIZE;

        flags |= FEC_BD_TR | FEC_BD_LG;

    }

    /* Frames larger than the user limit just set error flags.  */

    if (size > (s->rcr >> 16)) {

        flags |= FEC_BD_LG;

    }

    addr = s->rx_descriptor;

    while (size > 0) {

        mcf_fec_read_bd(&bd, addr);

        if ((bd.flags & FEC_BD_E) == 0) {

            /* No descriptors available.  Bail out.  */

            /* FIXME: This is wrong.  We should probably either save the

               remainder for when more RX buffers are available, or

               flag an error.  */

            fprintf(stderr, "mcf_fec: Lost end of frame\n");

            break;

        }

        buf_len = (size <= s->emrbr) ? size: s->emrbr;

        bd.length = buf_len;

        size -= buf_len;

        DPRINTF("rx_bd %x length %d\n", addr, bd.length);

        /* The last 4 bytes are the CRC.  */

        if (size < 4)

            buf_len += size - 4;

        buf_addr = bd.data;

        cpu_physical_memory_write(buf_addr, buf, buf_len);

        buf += buf_len;

        if (size < 4) {

            cpu_physical_memory_write(buf_addr + buf_len, crc_ptr, 4 - size);

            crc_ptr += 4 - size;

        }

        bd.flags &= ~FEC_BD_E;

        if (size == 0) {

            /* Last buffer in frame.  */

            bd.flags |= flags | FEC_BD_L;

            DPRINTF("rx frame flags %04x\n", bd.flags);

            s->eir |= FEC_INT_RXF;

        } else {

            s->eir |= FEC_INT_RXB;

        }

        mcf_fec_write_bd(&bd, addr);

        /* Advance to the next descriptor.  */

        if ((bd.flags & FEC_BD_W) != 0) {

            addr = s->erdsr;

        } else {

            addr += 8;

        }

    }

    s->rx_descriptor = addr;

    mcf_fec_enable_rx(s);

    mcf_fec_update(s);

}

static CPUReadMemoryFunc *mcf_fec_readfn[] = {

   mcf_fec_read,

   mcf_fec_read,

   mcf_fec_read

};

static CPUWriteMemoryFunc *mcf_fec_writefn[] = {

   mcf_fec_write,

   mcf_fec_write,

   mcf_fec_write

};

void mcf_fec_init(NICInfo *nd, target_phys_addr_t base, qemu_irq *irq)

{

    mcf_fec_state *s;

    int iomemtype;

    s = (mcf_fec_state *)qemu_mallocz(sizeof(mcf_fec_state));

    s->irq = irq;

    iomemtype = cpu_register_io_memory(0, mcf_fec_readfn,

                                       mcf_fec_writefn, s);

    cpu_register_physical_memory(base, 0x400, iomemtype);

    s->vc = qemu_new_vlan_client(nd->vlan, mcf_fec_receive,

                                 mcf_fec_can_receive, s);

    memcpy(s->macaddr, nd->macaddr, 6);

}