Archipelago » qemu

/*

 *  QEMU model of the Milkymist minimac2 block.

 *

 *  Copyright (c) 2011 Michael Walle <michael@walle.cc>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 *

 *

 * Specification available at:

 *   not available yet

 *

 */

#include "hw.h"

#include "sysbus.h"

#include "trace.h"

#include "net/net.h"

#include "qemu/error-report.h"

#include "qdev-addr.h"

#include <zlib.h>

enum {

    R_SETUP = 0,

    R_MDIO,

    R_STATE0,

    R_COUNT0,

    R_STATE1,

    R_COUNT1,

    R_TXCOUNT,

    R_MAX

};

enum {

    SETUP_PHY_RST = (1<<0),

};

enum {

    MDIO_DO  = (1<<0),

    MDIO_DI  = (1<<1),

    MDIO_OE  = (1<<2),

    MDIO_CLK = (1<<3),

};

enum {

    STATE_EMPTY   = 0,

    STATE_LOADED  = 1,

    STATE_PENDING = 2,

};

enum {

    MDIO_OP_WRITE = 1,

    MDIO_OP_READ  = 2,

};

enum mdio_state {

    MDIO_STATE_IDLE,

    MDIO_STATE_READING,

    MDIO_STATE_WRITING,

};

enum {

    R_PHY_ID1  = 2,

    R_PHY_ID2  = 3,

    R_PHY_MAX  = 32

};

#define MINIMAC2_MTU 1530

#define MINIMAC2_BUFFER_SIZE 2048

struct MilkymistMinimac2MdioState {

    int last_clk;

    int count;

    uint32_t data;

    uint16_t data_out;

    int state;

    uint8_t phy_addr;

    uint8_t reg_addr;

};

typedef struct MilkymistMinimac2MdioState MilkymistMinimac2MdioState;

struct MilkymistMinimac2State {

    SysBusDevice busdev;

    NICState *nic;

    NICConf conf;

    char *phy_model;

    hwaddr buffers_base;

    MemoryRegion buffers;

    MemoryRegion regs_region;

    qemu_irq rx_irq;

    qemu_irq tx_irq;

    uint32_t regs[R_MAX];

    MilkymistMinimac2MdioState mdio;

    uint16_t phy_regs[R_PHY_MAX];

    uint8_t *rx0_buf;

    uint8_t *rx1_buf;

    uint8_t *tx_buf;

};

typedef struct MilkymistMinimac2State MilkymistMinimac2State;

static const uint8_t preamble_sfd[] = {

        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0xd5

};

static void minimac2_mdio_write_reg(MilkymistMinimac2State *s,

        uint8_t phy_addr, uint8_t reg_addr, uint16_t value)

{

    trace_milkymist_minimac2_mdio_write(phy_addr, reg_addr, value);

    /* nop */

}

static uint16_t minimac2_mdio_read_reg(MilkymistMinimac2State *s,

        uint8_t phy_addr, uint8_t reg_addr)

{

    uint16_t r = s->phy_regs[reg_addr];

    trace_milkymist_minimac2_mdio_read(phy_addr, reg_addr, r);

    return r;

}

static void minimac2_update_mdio(MilkymistMinimac2State *s)

{

    MilkymistMinimac2MdioState *m = &s->mdio;

    /* detect rising clk edge */

    if (m->last_clk == 0 && (s->regs[R_MDIO] & MDIO_CLK)) {

        /* shift data in */

        int bit = ((s->regs[R_MDIO] & MDIO_DO)

                   && (s->regs[R_MDIO] & MDIO_OE)) ? 1 : 0;

        m->data = (m->data << 1) | bit;

        /* check for sync */

        if (m->data == 0xffffffff) {

            m->count = 32;

        }

        if (m->count == 16) {

            uint8_t start = (m->data >> 14) & 0x3;

            uint8_t op = (m->data >> 12) & 0x3;

            uint8_t ta = (m->data) & 0x3;

            if (start == 1 && op == MDIO_OP_WRITE && ta == 2) {

                m->state = MDIO_STATE_WRITING;

            } else if (start == 1 && op == MDIO_OP_READ && (ta & 1) == 0) {

                m->state = MDIO_STATE_READING;

            } else {

                m->state = MDIO_STATE_IDLE;

            }

            if (m->state != MDIO_STATE_IDLE) {

                m->phy_addr = (m->data >> 7) & 0x1f;

                m->reg_addr = (m->data >> 2) & 0x1f;

            }

            if (m->state == MDIO_STATE_READING) {

                m->data_out = minimac2_mdio_read_reg(s, m->phy_addr,

                        m->reg_addr);

            }

        }

        if (m->count < 16 && m->state == MDIO_STATE_READING) {

            int bit = (m->data_out & 0x8000) ? 1 : 0;

            m->data_out <<= 1;

            if (bit) {

                s->regs[R_MDIO] |= MDIO_DI;

            } else {

                s->regs[R_MDIO] &= ~MDIO_DI;

            }

        }

        if (m->count == 0 && m->state) {

            if (m->state == MDIO_STATE_WRITING) {

                uint16_t data = m->data & 0xffff;

                minimac2_mdio_write_reg(s, m->phy_addr, m->reg_addr, data);

            }

            m->state = MDIO_STATE_IDLE;

        }

        m->count--;

    }

    m->last_clk = (s->regs[R_MDIO] & MDIO_CLK) ? 1 : 0;

}

static size_t assemble_frame(uint8_t *buf, size_t size,

        const uint8_t *payload, size_t payload_size)

{

    uint32_t crc;

    if (size < payload_size + 12) {

        error_report("milkymist_minimac2: received too big ethernet frame");

        return 0;

    }

    /* prepend preamble and sfd */

    memcpy(buf, preamble_sfd, 8);

    /* now copy the payload */

    memcpy(buf + 8, payload, payload_size);

    /* pad frame if needed */

    if (payload_size < 60) {

        memset(buf + payload_size + 8, 0, 60 - payload_size);

        payload_size = 60;

    }

    /* append fcs */

    crc = cpu_to_le32(crc32(0, buf + 8, payload_size));

    memcpy(buf + payload_size + 8, &crc, 4);

    return payload_size + 12;

}

static void minimac2_tx(MilkymistMinimac2State *s)

{

    uint32_t txcount = s->regs[R_TXCOUNT];

    uint8_t *buf = s->tx_buf;

    if (txcount < 64) {

        error_report("milkymist_minimac2: ethernet frame too small (%u < %u)",

                txcount, 64);

        goto err;

    }

    if (txcount > MINIMAC2_MTU) {

        error_report("milkymist_minimac2: MTU exceeded (%u > %u)",

                txcount, MINIMAC2_MTU);

        goto err;

    }

    if (memcmp(buf, preamble_sfd, 8) != 0) {

        error_report("milkymist_minimac2: frame doesn't contain the preamble "

                "and/or the SFD (%02x %02x %02x %02x %02x %02x %02x %02x)",

                buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);

        goto err;

    }

    trace_milkymist_minimac2_tx_frame(txcount - 12);

    /* send packet, skipping preamble and sfd */

    qemu_send_packet_raw(&s->nic->nc, buf + 8, txcount - 12);

    s->regs[R_TXCOUNT] = 0;

err:

    trace_milkymist_minimac2_pulse_irq_tx();

    qemu_irq_pulse(s->tx_irq);

}

static void update_rx_interrupt(MilkymistMinimac2State *s)

{

    if (s->regs[R_STATE0] == STATE_PENDING

            || s->regs[R_STATE1] == STATE_PENDING) {

        trace_milkymist_minimac2_raise_irq_rx();

        qemu_irq_raise(s->rx_irq);

    } else {

        trace_milkymist_minimac2_lower_irq_rx();

        qemu_irq_lower(s->rx_irq);

    }

}

static ssize_t minimac2_rx(NetClientState *nc, const uint8_t *buf, size_t size)

{

    MilkymistMinimac2State *s = DO_UPCAST(NICState, nc, nc)->opaque;

    uint32_t r_count;

    uint32_t r_state;

    uint8_t *rx_buf;

    size_t frame_size;

    trace_milkymist_minimac2_rx_frame(buf, size);

    /* choose appropriate slot */

    if (s->regs[R_STATE0] == STATE_LOADED) {

        r_count = R_COUNT0;

        r_state = R_STATE0;

        rx_buf = s->rx0_buf;

    } else if (s->regs[R_STATE1] == STATE_LOADED) {

        r_count = R_COUNT1;

        r_state = R_STATE1;

        rx_buf = s->rx1_buf;

    } else {

        trace_milkymist_minimac2_drop_rx_frame(buf);

        return size;

    }

    /* assemble frame */

    frame_size = assemble_frame(rx_buf, MINIMAC2_BUFFER_SIZE, buf, size);

    if (frame_size == 0) {

        return size;

    }

    trace_milkymist_minimac2_rx_transfer(rx_buf, frame_size);

    /* update slot */

    s->regs[r_count] = frame_size;

    s->regs[r_state] = STATE_PENDING;

    update_rx_interrupt(s);

    return size;

}

static uint64_t

minimac2_read(void *opaque, hwaddr addr, unsigned size)

{

    MilkymistMinimac2State *s = opaque;

    uint32_t r = 0;

    addr >>= 2;

    switch (addr) {

    case R_SETUP:

    case R_MDIO:

    case R_STATE0:

    case R_COUNT0:

    case R_STATE1:

    case R_COUNT1:

    case R_TXCOUNT:

        r = s->regs[addr];

        break;

    default:

        error_report("milkymist_minimac2: read access to unknown register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    }

    trace_milkymist_minimac2_memory_read(addr << 2, r);

    return r;

}

static void

minimac2_write(void *opaque, hwaddr addr, uint64_t value,

               unsigned size)

{

    MilkymistMinimac2State *s = opaque;

    trace_milkymist_minimac2_memory_read(addr, value);

    addr >>= 2;

    switch (addr) {

    case R_MDIO:

    {

        /* MDIO_DI is read only */

        int mdio_di = (s->regs[R_MDIO] & MDIO_DI);

        s->regs[R_MDIO] = value;

        if (mdio_di) {

            s->regs[R_MDIO] |= mdio_di;

        } else {

            s->regs[R_MDIO] &= ~mdio_di;

        }

        minimac2_update_mdio(s);

    } break;

    case R_TXCOUNT:

        s->regs[addr] = value;

        if (value > 0) {

            minimac2_tx(s);

        }

        break;

    case R_STATE0:

    case R_STATE1:

        s->regs[addr] = value;

        update_rx_interrupt(s);

        break;

    case R_SETUP:

    case R_COUNT0:

    case R_COUNT1:

        s->regs[addr] = value;

        break;

    default:

        error_report("milkymist_minimac2: write access to unknown register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    }

}

static const MemoryRegionOps minimac2_ops = {

    .read = minimac2_read,

    .write = minimac2_write,

    .valid = {

        .min_access_size = 4,

        .max_access_size = 4,

    },

    .endianness = DEVICE_NATIVE_ENDIAN,

};

static int minimac2_can_rx(NetClientState *nc)

{

    MilkymistMinimac2State *s = DO_UPCAST(NICState, nc, nc)->opaque;

    if (s->regs[R_STATE0] == STATE_LOADED) {

        return 1;

    }

    if (s->regs[R_STATE1] == STATE_LOADED) {

        return 1;

    }

    return 0;

}

static void minimac2_cleanup(NetClientState *nc)

{

    MilkymistMinimac2State *s = DO_UPCAST(NICState, nc, nc)->opaque;

    s->nic = NULL;

}

static void milkymist_minimac2_reset(DeviceState *d)

{

    MilkymistMinimac2State *s =

            container_of(d, MilkymistMinimac2State, busdev.qdev);

    int i;

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

        s->regs[i] = 0;

    }

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

        s->phy_regs[i] = 0;

    }

    /* defaults */

    s->phy_regs[R_PHY_ID1] = 0x0022; /* Micrel KSZ8001L */

    s->phy_regs[R_PHY_ID2] = 0x161a;

}

static NetClientInfo net_milkymist_minimac2_info = {

    .type = NET_CLIENT_OPTIONS_KIND_NIC,

    .size = sizeof(NICState),

    .can_receive = minimac2_can_rx,

    .receive = minimac2_rx,

    .cleanup = minimac2_cleanup,

};

static int milkymist_minimac2_init(SysBusDevice *dev)

{

    MilkymistMinimac2State *s = FROM_SYSBUS(typeof(*s), dev);

    size_t buffers_size = TARGET_PAGE_ALIGN(3 * MINIMAC2_BUFFER_SIZE);

    sysbus_init_irq(dev, &s->rx_irq);

    sysbus_init_irq(dev, &s->tx_irq);

    memory_region_init_io(&s->regs_region, &minimac2_ops, s,

                          "milkymist-minimac2", R_MAX * 4);

    sysbus_init_mmio(dev, &s->regs_region);

    /* register buffers memory */

    memory_region_init_ram(&s->buffers, "milkymist-minimac2.buffers",

                           buffers_size);

    vmstate_register_ram_global(&s->buffers);

    s->rx0_buf = memory_region_get_ram_ptr(&s->buffers);

    s->rx1_buf = s->rx0_buf + MINIMAC2_BUFFER_SIZE;

    s->tx_buf = s->rx1_buf + MINIMAC2_BUFFER_SIZE;

    sysbus_add_memory(dev, s->buffers_base, &s->buffers);

    qemu_macaddr_default_if_unset(&s->conf.macaddr);

    s->nic = qemu_new_nic(&net_milkymist_minimac2_info, &s->conf,

                          object_get_typename(OBJECT(dev)), dev->qdev.id, s);

    qemu_format_nic_info_str(&s->nic->nc, s->conf.macaddr.a);

    return 0;

}

static const VMStateDescription vmstate_milkymist_minimac2_mdio = {

    .name = "milkymist-minimac2-mdio",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .fields      = (VMStateField[]) {

        VMSTATE_INT32(last_clk, MilkymistMinimac2MdioState),

        VMSTATE_INT32(count, MilkymistMinimac2MdioState),

        VMSTATE_UINT32(data, MilkymistMinimac2MdioState),

        VMSTATE_UINT16(data_out, MilkymistMinimac2MdioState),

        VMSTATE_INT32(state, MilkymistMinimac2MdioState),

        VMSTATE_UINT8(phy_addr, MilkymistMinimac2MdioState),

        VMSTATE_UINT8(reg_addr, MilkymistMinimac2MdioState),

        VMSTATE_END_OF_LIST()

    }

};

static const VMStateDescription vmstate_milkymist_minimac2 = {

    .name = "milkymist-minimac2",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .fields      = (VMStateField[]) {

        VMSTATE_UINT32_ARRAY(regs, MilkymistMinimac2State, R_MAX),

        VMSTATE_UINT16_ARRAY(phy_regs, MilkymistMinimac2State, R_PHY_MAX),

        VMSTATE_STRUCT(mdio, MilkymistMinimac2State, 0,

                vmstate_milkymist_minimac2_mdio, MilkymistMinimac2MdioState),

        VMSTATE_END_OF_LIST()

    }

};

static Property milkymist_minimac2_properties[] = {

    DEFINE_PROP_TADDR("buffers_base", MilkymistMinimac2State,

    buffers_base, 0),

    DEFINE_NIC_PROPERTIES(MilkymistMinimac2State, conf),

    DEFINE_PROP_STRING("phy_model", MilkymistMinimac2State, phy_model),

    DEFINE_PROP_END_OF_LIST(),

};

static void milkymist_minimac2_class_init(ObjectClass *klass, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = milkymist_minimac2_init;

    dc->reset = milkymist_minimac2_reset;

    dc->vmsd = &vmstate_milkymist_minimac2;

    dc->props = milkymist_minimac2_properties;

}

static TypeInfo milkymist_minimac2_info = {

    .name          = "milkymist-minimac2",

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(MilkymistMinimac2State),

    .class_init    = milkymist_minimac2_class_init,

};

static void milkymist_minimac2_register_types(void)

{

    type_register_static(&milkymist_minimac2_info);

}

type_init(milkymist_minimac2_register_types)