/*

 * Luminary Micro Stellaris Ethernet Controller

 *

 * Copyright (c) 2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the GPL.

 */

#include "hw.h"

#include "arm-misc.h"

#include "net.h"

#include <zlib.h>

//#define DEBUG_STELLARIS_ENET 1

#ifdef DEBUG_STELLARIS_ENET

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

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

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

do { fprintf(stderr, "stellaris_enet: error: " fmt , ##args); exit(1);} while (0)

#else

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

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

do { fprintf(stderr, "stellaris_enet: error: " fmt , ##args);} while (0)

#endif

#define SE_INT_RX       0x01

#define SE_INT_TXER     0x02

#define SE_INT_TXEMP    0x04

#define SE_INT_FOV      0x08

#define SE_INT_RXER     0x10

#define SE_INT_MD       0x20

#define SE_INT_PHY      0x40

#define SE_RCTL_RXEN    0x01

#define SE_RCTL_AMUL    0x02

#define SE_RCTL_PRMS    0x04

#define SE_RCTL_BADCRC  0x08

#define SE_RCTL_RSTFIFO 0x10

#define SE_TCTL_TXEN    0x01

#define SE_TCTL_PADEN   0x02

#define SE_TCTL_CRC     0x04

#define SE_TCTL_DUPLEX  0x08

typedef struct {

    uint32_t ris;

    uint32_t im;

    uint32_t rctl;

    uint32_t tctl;

    uint32_t thr;

    uint32_t mctl;

    uint32_t mdv;

    uint32_t mtxd;

    uint32_t mrxd;

    uint32_t np;

    int tx_frame_len;

    int tx_fifo_len;

    uint8_t tx_fifo[2048];

    /* Real hardware has a 2k fifo, which works out to be at most 31 packets.

       We implement a full 31 packet fifo.  */

    struct {

        uint8_t data[2048];

        int len;

    } rx[31];

    uint8_t *rx_fifo;

    int rx_fifo_len;

    int next_packet;

    VLANClientState *vc;

    qemu_irq irq;

    uint8_t macaddr[6];

} stellaris_enet_state;

static void stellaris_enet_update(stellaris_enet_state *s)

{

    qemu_set_irq(s->irq, (s->ris & s->im) != 0);

}

/* TODO: Implement MAC address filtering.  */

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

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    int n;

    uint8_t *p;

    uint32_t crc;

    if ((s->rctl & SE_RCTL_RXEN) == 0)

        return;

    if (s->np >= 31) {

        DPRINTF("Packet dropped\n");

        return;

    }

    DPRINTF("Received packet len=%d\n", size);

    n = s->next_packet + s->np;

    if (n >= 31)

        n -= 31;

    s->np++;

    s->rx[n].len = size + 6;

    p = s->rx[n].data;

    *(p++) = (size + 6);

    *(p++) = (size + 6) >> 8;

    memcpy (p, buf, size);

    p += size;

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

    *(p++) = crc;

    *(p++) = crc >> 8;

    *(p++) = crc >> 16;

    *(p++) = crc >> 24;

    /* Clear the remaining bytes in the last word.  */

    if ((size & 3) != 2) {

        memset(p, 0, (6 - size) & 3);

    }

    s->ris |= SE_INT_RX;

    stellaris_enet_update(s);

}

static int stellaris_enet_can_receive(void *opaque)

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    if ((s->rctl & SE_RCTL_RXEN) == 0)

        return 1;

    return (s->np < 31);

}

static uint32_t stellaris_enet_read(void *opaque, target_phys_addr_t offset)

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    uint32_t val;

    switch (offset) {

    case 0x00: /* RIS */

        DPRINTF("IRQ status %02x\n", s->ris);

        return s->ris;

    case 0x04: /* IM */

        return s->im;

    case 0x08: /* RCTL */

        return s->rctl;

    case 0x0c: /* TCTL */

        return s->tctl;

    case 0x10: /* DATA */

        if (s->rx_fifo_len == 0) {

            if (s->np == 0) {

                BADF("RX underflow\n");

                return 0;

            }

            s->rx_fifo_len = s->rx[s->next_packet].len;

            s->rx_fifo = s->rx[s->next_packet].data;

            DPRINTF("RX FIFO start packet len=%d\n", s->rx_fifo_len);

        }

        val = s->rx_fifo[0] | (s->rx_fifo[1] << 8) | (s->rx_fifo[2] << 16)

              | (s->rx_fifo[3] << 24);

        s->rx_fifo += 4;

        s->rx_fifo_len -= 4;

        if (s->rx_fifo_len <= 0) {

            s->rx_fifo_len = 0;

            s->next_packet++;

            if (s->next_packet >= 31)

                s->next_packet = 0;

            s->np--;

            DPRINTF("RX done np=%d\n", s->np);

        }

        return val;

    case 0x14: /* IA0 */

        return s->macaddr[0] | (s->macaddr[1] << 8)

               | (s->macaddr[2] << 16) | (s->macaddr[3] << 24);

    case 0x18: /* IA1 */

        return s->macaddr[4] | (s->macaddr[5] << 8);

    case 0x1c: /* THR */

        return s->thr;

    case 0x20: /* MCTL */

        return s->mctl;

    case 0x24: /* MDV */

        return s->mdv;

    case 0x28: /* MADD */

        return 0;

    case 0x2c: /* MTXD */

        return s->mtxd;

    case 0x30: /* MRXD */

        return s->mrxd;

    case 0x34: /* NP */

        return s->np;

    case 0x38: /* TR */

        return 0;

    case 0x3c: /* Undocuented: Timestamp? */

        return 0;

    default:

        cpu_abort (cpu_single_env, "stellaris_enet_read: Bad offset %x\n",

                   (int)offset);

        return 0;

    }

}

static void stellaris_enet_write(void *opaque, target_phys_addr_t offset,

                        uint32_t value)

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    switch (offset) {

    case 0x00: /* IACK */

        s->ris &= ~value;

        DPRINTF("IRQ ack %02x/%02x\n", value, s->ris);

        stellaris_enet_update(s);

        /* Clearing TXER also resets the TX fifo.  */

        if (value & SE_INT_TXER)

            s->tx_frame_len = -1;

        break;

    case 0x04: /* IM */

        DPRINTF("IRQ mask %02x/%02x\n", value, s->ris);

        s->im = value;

        stellaris_enet_update(s);

        break;

    case 0x08: /* RCTL */

        s->rctl = value;

        if (value & SE_RCTL_RSTFIFO) {

            s->rx_fifo_len = 0;

            s->np = 0;

            stellaris_enet_update(s);

        }

        break;

    case 0x0c: /* TCTL */

        s->tctl = value;

        break;

    case 0x10: /* DATA */

        if (s->tx_frame_len == -1) {

            s->tx_frame_len = value & 0xffff;

            if (s->tx_frame_len > 2032) {

                DPRINTF("TX frame too long (%d)\n", s->tx_frame_len);

                s->tx_frame_len = 0;

                s->ris |= SE_INT_TXER;

                stellaris_enet_update(s);

            } else {

                DPRINTF("Start TX frame len=%d\n", s->tx_frame_len);

                /* The value written does not include the ethernet header.  */

                s->tx_frame_len += 14;

                if ((s->tctl & SE_TCTL_CRC) == 0)

                    s->tx_frame_len += 4;

                s->tx_fifo_len = 0;

                s->tx_fifo[s->tx_fifo_len++] = value >> 16;

                s->tx_fifo[s->tx_fifo_len++] = value >> 24;

            }

        } else {

            s->tx_fifo[s->tx_fifo_len++] = value;

            s->tx_fifo[s->tx_fifo_len++] = value >> 8;

            s->tx_fifo[s->tx_fifo_len++] = value >> 16;

            s->tx_fifo[s->tx_fifo_len++] = value >> 24;

            if (s->tx_fifo_len >= s->tx_frame_len) {

                /* We don't implement explicit CRC, so just chop it off.  */

                if ((s->tctl & SE_TCTL_CRC) == 0)

                    s->tx_frame_len -= 4;

                if ((s->tctl & SE_TCTL_PADEN) && s->tx_frame_len < 60) {

                    memset(&s->tx_fifo[s->tx_frame_len], 0, 60 - s->tx_frame_len);

                    s->tx_fifo_len = 60;

                }

                qemu_send_packet(s->vc, s->tx_fifo, s->tx_frame_len);

                s->tx_frame_len = -1;

                s->ris |= SE_INT_TXEMP;

                stellaris_enet_update(s);

                DPRINTF("Done TX\n");

            }

        }

        break;

    case 0x14: /* IA0 */

        s->macaddr[0] = value;

        s->macaddr[1] = value >> 8;

        s->macaddr[2] = value >> 16;

        s->macaddr[3] = value >> 24;

        break;

    case 0x18: /* IA1 */

        s->macaddr[4] = value;

        s->macaddr[5] = value >> 8;

        break;

    case 0x1c: /* THR */

        s->thr = value;

        break;

    case 0x20: /* MCTL */

        s->mctl = value;

        break;

    case 0x24: /* MDV */

        s->mdv = value;

        break;

    case 0x28: /* MADD */

        /* ignored.  */

        break;

    case 0x2c: /* MTXD */

        s->mtxd = value & 0xff;

        break;

    case 0x30: /* MRXD */

    case 0x34: /* NP */

    case 0x38: /* TR */

        /* Ignored.  */

    case 0x3c: /* Undocuented: Timestamp? */

        /* Ignored.  */

        break;

    default:

        cpu_abort (cpu_single_env, "stellaris_enet_write: Bad offset %x\n",

                   (int)offset);

    }

}

static CPUReadMemoryFunc *stellaris_enet_readfn[] = {

   stellaris_enet_read,

   stellaris_enet_read,

   stellaris_enet_read

};

static CPUWriteMemoryFunc *stellaris_enet_writefn[] = {

   stellaris_enet_write,

   stellaris_enet_write,

   stellaris_enet_write

};

static void stellaris_enet_reset(stellaris_enet_state *s)

{

    s->mdv = 0x80;

    s->rctl = SE_RCTL_BADCRC;

    s->im = SE_INT_PHY | SE_INT_MD | SE_INT_RXER | SE_INT_FOV | SE_INT_TXEMP

            | SE_INT_TXER | SE_INT_RX;

    s->thr = 0x3f;

    s->tx_frame_len = -1;

}

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

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    int i;

    qemu_put_be32(f, s->ris);

    qemu_put_be32(f, s->im);

    qemu_put_be32(f, s->rctl);

    qemu_put_be32(f, s->tctl);

    qemu_put_be32(f, s->thr);

    qemu_put_be32(f, s->mctl);

    qemu_put_be32(f, s->mdv);

    qemu_put_be32(f, s->mtxd);

    qemu_put_be32(f, s->mrxd);

    qemu_put_be32(f, s->np);

    qemu_put_be32(f, s->tx_frame_len);

    qemu_put_be32(f, s->tx_fifo_len);

    qemu_put_buffer(f, s->tx_fifo, sizeof(s->tx_fifo));

    for (i = 0; i < 31; i++) {

        qemu_put_be32(f, s->rx[i].len);

        qemu_put_buffer(f, s->rx[i].data, sizeof(s->rx[i].data));

    }

    qemu_put_be32(f, s->next_packet);

    qemu_put_be32(f, s->rx_fifo - s->rx[s->next_packet].data);

    qemu_put_be32(f, s->rx_fifo_len);

}

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

{

    stellaris_enet_state *s = (stellaris_enet_state *)opaque;

    int i;

    if (version_id != 1)

        return -EINVAL;

    s->ris = qemu_get_be32(f);

    s->im = qemu_get_be32(f);

    s->rctl = qemu_get_be32(f);

    s->tctl = qemu_get_be32(f);

    s->thr = qemu_get_be32(f);

    s->mctl = qemu_get_be32(f);

    s->mdv = qemu_get_be32(f);

    s->mtxd = qemu_get_be32(f);

    s->mrxd = qemu_get_be32(f);

    s->np = qemu_get_be32(f);

    s->tx_frame_len = qemu_get_be32(f);

    s->tx_fifo_len = qemu_get_be32(f);

    qemu_get_buffer(f, s->tx_fifo, sizeof(s->tx_fifo));

    for (i = 0; i < 31; i++) {

        s->rx[i].len = qemu_get_be32(f);

        qemu_get_buffer(f, s->rx[i].data, sizeof(s->rx[i].data));

    }

    s->next_packet = qemu_get_be32(f);

    s->rx_fifo = s->rx[s->next_packet].data + qemu_get_be32(f);

    s->rx_fifo_len = qemu_get_be32(f);

    return 0;

}

void stellaris_enet_init(NICInfo *nd, uint32_t base, qemu_irq irq)

{

    stellaris_enet_state *s;

    int iomemtype;

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

    iomemtype = cpu_register_io_memory(0, stellaris_enet_readfn,

                                       stellaris_enet_writefn, s);

    cpu_register_physical_memory(base, 0x00001000, iomemtype);

    s->irq = irq;

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

    if (nd->vlan)

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

                                     stellaris_enet_can_receive, s);

    stellaris_enet_reset(s);

    register_savevm("stellaris_enet", -1, 1,

                    stellaris_enet_save, stellaris_enet_load, s);

}