[Qemu-devel] [PATCH v13 15/19] i.MX: Add FEC Ethernet Emulator

[Jean-Christophe Dubois <jcd@tribudubois.net>]

This is based on mcf_fec.c FEC implementation for Coldfire

  * A generic PHY was added (borrowwed from LAN9118)
  * The buffer management is also modified as buffers are
    slightly different between Coldfire and i.MX

Signed-off-by: Jean-Christophe Dubois <jcd@tribudubois.net>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
---

Changes since v1:
    * none

Changes since v2:
    * use QOM cast
    * reworked debug printf
    * use CamelCase for state type
    * warn with qemu_log_mask(LOG_GUEST_ERROR) or qemu_log_mask(LOG_UNIMP)
    * move to dma_memory_read/write API
    * rework interrupt handling
    * use qemu_flush_queued_packets() in rx_enable()
    
Changes since v3:
    * use realise for device initialization
    * More QOM cast
    * reworked debug printf some more
    * standardise GPL header
    * use CamelCase for buffer descriptor type

Changes since v4:
    * none

Changes since v5: 
    * replace hw_error() with qemu_log_mask(LOG_GUEST_ERROR, ...)
    * remove reformating of imx.h header file.
    * remove unnecessary spaces.

Changes since v6:
    * port to new memory API

Changes since v7:
    * refactor to be used by SOC

Changes since v8:
    * no change

Changes since v9:
    * no change

Changes since v10:
    * no change

Changes since v11:
    * no change

Changes since v12:
    * no change

 default-configs/arm-softmmu.mak |   1 +
 hw/net/Makefile.objs            |   1 +
 hw/net/imx_fec.c                | 709 ++++++++++++++++++++++++++++++++++++++++
 include/hw/net/imx_fec.h        | 113 +++++++
 4 files changed, 824 insertions(+)
 create mode 100644 hw/net/imx_fec.c
 create mode 100644 include/hw/net/imx_fec.h

diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index 47390db..5fa84c6 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -28,6 +28,7 @@ CONFIG_SSI_M25P80=y
 CONFIG_LAN9118=y
 CONFIG_SMC91C111=y
 CONFIG_ALLWINNER_EMAC=y
+CONFIG_IMX_FEC=y
 CONFIG_DS1338=y
 CONFIG_PFLASH_CFI01=y
 CONFIG_PFLASH_CFI02=y
diff --git a/hw/net/Makefile.objs b/hw/net/Makefile.objs
index 9880173..64d0449 100644
--- a/hw/net/Makefile.objs
+++ b/hw/net/Makefile.objs
@@ -19,6 +19,7 @@ common-obj-$(CONFIG_XGMAC) += xgmac.o
 common-obj-$(CONFIG_MIPSNET) += mipsnet.o
 common-obj-$(CONFIG_XILINX_AXI) += xilinx_axienet.o
 common-obj-$(CONFIG_ALLWINNER_EMAC) += allwinner_emac.o
+common-obj-$(CONFIG_IMX_FEC) += imx_fec.o
 
 common-obj-$(CONFIG_CADENCE) += cadence_gem.o
 common-obj-$(CONFIG_STELLARIS_ENET) += stellaris_enet.o
diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
new file mode 100644
index 0000000..725f3fa
--- /dev/null
+++ b/hw/net/imx_fec.c
@@ -0,0 +1,709 @@
+/*
+ * i.MX Fast Ethernet Controller emulation.
+ *
+ * Copyright (c) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net>
+ *
+ * Based on Coldfire Fast Ethernet Controller emulation.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "hw/net/imx_fec.h"
+#include "sysemu/dma.h"
+
+/* For crc32 */
+#include <zlib.h>
+
+#ifndef IMX_FEC_DEBUG
+#define IMX_FEC_DEBUG          0
+#endif
+
+#ifndef IMX_PHY_DEBUG
+#define IMX_PHY_DEBUG          0
+#endif
+
+#if IMX_FEC_DEBUG
+#define FEC_PRINTF(fmt, ...) \
+    do { fprintf(stderr, "%s[%s]: " fmt , TYPE_IMX_FEC, __func__, \
+                 ## __VA_ARGS__); \
+    } while (0)
+#else
+#define FEC_PRINTF(fmt, ...) do {} while (0)
+#endif
+
+#if IMX_PHY_DEBUG
+#define PHY_PRINTF(fmt, ...) \
+    do { fprintf(stderr, "%s.phy[%s]: " fmt , TYPE_IMX_FEC, __func__, \
+                 ## __VA_ARGS__); \
+    } while (0)
+#else
+#define PHY_PRINTF(fmt, ...) do {} while (0)
+#endif
+
+static const VMStateDescription vmstate_imx_fec = {
+    .name = TYPE_IMX_FEC,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(irq_state, IMXFECState),
+        VMSTATE_UINT32(eir, IMXFECState),
+        VMSTATE_UINT32(eimr, IMXFECState),
+        VMSTATE_UINT32(rx_enabled, IMXFECState),
+        VMSTATE_UINT32(rx_descriptor, IMXFECState),
+        VMSTATE_UINT32(tx_descriptor, IMXFECState),
+        VMSTATE_UINT32(ecr, IMXFECState),
+        VMSTATE_UINT32(mmfr, IMXFECState),
+        VMSTATE_UINT32(mscr, IMXFECState),
+        VMSTATE_UINT32(mibc, IMXFECState),
+        VMSTATE_UINT32(rcr, IMXFECState),
+        VMSTATE_UINT32(tcr, IMXFECState),
+        VMSTATE_UINT32(tfwr, IMXFECState),
+        VMSTATE_UINT32(frsr, IMXFECState),
+        VMSTATE_UINT32(erdsr, IMXFECState),
+        VMSTATE_UINT32(etdsr, IMXFECState),
+        VMSTATE_UINT32(emrbr, IMXFECState),
+        VMSTATE_UINT32(miigsk_cfgr, IMXFECState),
+        VMSTATE_UINT32(miigsk_enr, IMXFECState),
+
+        VMSTATE_UINT32(phy_status, IMXFECState),
+        VMSTATE_UINT32(phy_control, IMXFECState),
+        VMSTATE_UINT32(phy_advertise, IMXFECState),
+        VMSTATE_UINT32(phy_int, IMXFECState),
+        VMSTATE_UINT32(phy_int_mask, IMXFECState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+#define PHY_INT_ENERGYON            (1 << 7)
+#define PHY_INT_AUTONEG_COMPLETE    (1 << 6)
+#define PHY_INT_FAULT               (1 << 5)
+#define PHY_INT_DOWN                (1 << 4)
+#define PHY_INT_AUTONEG_LP          (1 << 3)
+#define PHY_INT_PARFAULT            (1 << 2)
+#define PHY_INT_AUTONEG_PAGE        (1 << 1)
+
+static void imx_fec_update(IMXFECState *s);
+
+/*
+ * The MII phy could raise a GPIO to the processor which in turn
+ * could be handled as an interrpt by the OS.
+ * For now we don't handle any GPIO/interrupt line, so the OS will
+ * have to poll for the PHY status.
+ */
+static void phy_update_irq(IMXFECState *s)
+{
+    imx_fec_update(s);
+}
+
+static void phy_update_link(IMXFECState *s)
+{
+    /* Autonegotiation status mirrors link status.  */
+    if (qemu_get_queue(s->nic)->link_down) {
+        PHY_PRINTF("link is down\n");
+        s->phy_status &= ~0x0024;
+        s->phy_int |= PHY_INT_DOWN;
+    } else {
+        PHY_PRINTF("link is up\n");
+        s->phy_status |= 0x0024;
+        s->phy_int |= PHY_INT_ENERGYON;
+        s->phy_int |= PHY_INT_AUTONEG_COMPLETE;
+    }
+    phy_update_irq(s);
+}
+
+static void imx_fec_set_link(NetClientState *nc)
+{
+    phy_update_link(IMX_FEC(qemu_get_nic_opaque(nc)));
+}
+
+static void phy_reset(IMXFECState *s)
+{
+    s->phy_status = 0x7809;
+    s->phy_control = 0x3000;
+    s->phy_advertise = 0x01e1;
+    s->phy_int_mask = 0;
+    s->phy_int = 0;
+    phy_update_link(s);
+}
+
+static uint32_t do_phy_read(IMXFECState *s, int reg)
+{
+    uint32_t val;
+
+    if (reg > 31) {
+        /* we only advertise one phy */
+        return 0;
+    }
+
+    switch (reg) {
+    case 0:     /* Basic Control */
+        val = s->phy_control;
+        break;
+    case 1:     /* Basic Status */
+        val = s->phy_status;
+        break;
+    case 2:     /* ID1 */
+        val = 0x0007;
+        break;
+    case 3:     /* ID2 */
+        val = 0xc0d1;
+        break;
+    case 4:     /* Auto-neg advertisement */
+        val = s->phy_advertise;
+        break;
+    case 5:     /* Auto-neg Link Partner Ability */
+        val = 0x0f71;
+        break;
+    case 6:     /* Auto-neg Expansion */
+        val = 1;
+        break;
+    case 29:    /* Interrupt source.  */
+        val = s->phy_int;
+        s->phy_int = 0;
+        phy_update_irq(s);
+        break;
+    case 30:    /* Interrupt mask */
+        val = s->phy_int_mask;
+        break;
+    case 17:
+    case 18:
+    case 27:
+    case 31:
+        qemu_log_mask(LOG_UNIMP, "%s.phy[%s]: reg %d not implemented\n",
+                      TYPE_IMX_FEC, __func__, reg);
+        val = 0;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_FEC, __func__, reg);
+        val = 0;
+        break;
+    }
+
+    PHY_PRINTF("read 0x%04x @ %d\n", val, reg);
+
+    return val;
+}
+
+static void do_phy_write(IMXFECState *s, int reg, uint32_t val)
+{
+    PHY_PRINTF("write 0x%04x @ %d\n", val, reg);
+
+    if (reg > 31) {
+        /* we only advertise one phy */
+        return;
+    }
+
+    switch (reg) {
+    case 0:     /* Basic Control */
+        if (val & 0x8000) {
+            phy_reset(s);
+        } else {
+            s->phy_control = val & 0x7980;
+            /* Complete autonegotiation immediately.  */
+            if (val & 0x1000) {
+                s->phy_status |= 0x0020;
+            }
+        }
+        break;
+    case 4:     /* Auto-neg advertisement */
+        s->phy_advertise = (val & 0x2d7f) | 0x80;
+        break;
+    case 30:    /* Interrupt mask */
+        s->phy_int_mask = val & 0xff;
+        phy_update_irq(s);
+        break;
+    case 17:
+    case 18:
+    case 27:
+    case 31:
+        qemu_log_mask(LOG_UNIMP, "%s.phy[%s]: reg %d not implemented\n",
+                      TYPE_IMX_FEC, __func__, reg);
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s.phy[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_FEC, __func__, reg);
+        break;
+    }
+}
+
+static void imx_fec_read_bd(IMXFECBufDesc *bd, dma_addr_t addr)
+{
+    dma_memory_read(&address_space_memory, addr, bd, sizeof(*bd));
+}
+
+static void imx_fec_write_bd(IMXFECBufDesc *bd, dma_addr_t addr)
+{
+    dma_memory_write(&address_space_memory, addr, bd, sizeof(*bd));
+}
+
+static void imx_fec_update(IMXFECState *s)
+{
+    uint32_t active;
+    uint32_t changed;
+
+    active = s->eir & s->eimr;
+    changed = active ^ s->irq_state;
+    if (changed) {
+        qemu_set_irq(s->irq, active);
+    }
+    s->irq_state = active;
+}
+
+static void imx_fec_do_tx(IMXFECState *s)
+{
+    int frame_size = 0;
+    uint8_t frame[FEC_MAX_FRAME_SIZE];
+    uint8_t *ptr = frame;
+    uint32_t addr = s->tx_descriptor;
+
+    while (1) {
+        IMXFECBufDesc bd;
+        int len;
+
+        imx_fec_read_bd(&bd, addr);
+        FEC_PRINTF("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;
+        }
+        dma_memory_read(&address_space_memory, bd.data, ptr, len);
+        ptr += len;
+        frame_size += len;
+        if (bd.flags & FEC_BD_L) {
+            /* Last buffer in frame.  */
+            qemu_send_packet(qemu_get_queue(s->nic), 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.  */
+        imx_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;
+
+    imx_fec_update(s);
+}
+
+static void imx_fec_enable_rx(IMXFECState *s)
+{
+    IMXFECBufDesc bd;
+    uint32_t tmp;
+
+    imx_fec_read_bd(&bd, s->rx_descriptor);
+
+    tmp = ((bd.flags & FEC_BD_E) != 0);
+
+    if (!tmp) {
+        FEC_PRINTF("RX buffer full\n");
+    } else if (!s->rx_enabled) {
+        qemu_flush_queued_packets(qemu_get_queue(s->nic));
+    }
+
+    s->rx_enabled = tmp;
+}
+
+static void imx_fec_reset(DeviceState *d)
+{
+    IMXFECState *s = IMX_FEC(d);
+
+    /* Reset the FEC */
+    s->eir = 0;
+    s->eimr = 0;
+    s->rx_enabled = 0;
+    s->ecr = 0;
+    s->mscr = 0;
+    s->mibc = 0xc0000000;
+    s->rcr = 0x05ee0001;
+    s->tcr = 0;
+    s->tfwr = 0;
+    s->frsr = 0x500;
+    s->miigsk_cfgr = 0;
+    s->miigsk_enr = 0x6;
+
+    /* We also reset the PHY */
+    phy_reset(s);
+}
+
+static uint64_t imx_fec_read(void *opaque, hwaddr addr, unsigned size)
+{
+    IMXFECState *s = IMX_FEC(opaque);
+
+    FEC_PRINTF("reading from @ 0x%03x\n", (int)addr);
+
+    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 s->mibc; /* MIBC */
+    case 0x084:
+        return s->rcr;
+    case 0x0c4:
+        return s->tcr;
+    case 0x0e4:     /* PALR */
+        return (s->conf.macaddr.a[0] << 24)
+               | (s->conf.macaddr.a[1] << 16)
+               | (s->conf.macaddr.a[2] << 8)
+               | s->conf.macaddr.a[3];
+        break;
+    case 0x0e8:     /* PAUR */
+        return (s->conf.macaddr.a[4] << 24)
+               | (s->conf.macaddr.a[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->frsr;
+    case 0x180:
+        return s->erdsr;
+    case 0x184:
+        return s->etdsr;
+    case 0x188:
+        return s->emrbr;
+    case 0x300:
+        return s->miigsk_cfgr;
+    case 0x308:
+        return s->miigsk_enr;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_FEC, __func__, (int)addr);
+        return 0;
+    }
+}
+
+static void imx_fec_write(void *opaque, hwaddr addr,
+                          uint64_t value, unsigned size)
+{
+    IMXFECState *s = IMX_FEC(opaque);
+
+    FEC_PRINTF("writing 0x%08x @ 0x%03x\n", (int)value, (int)addr);
+
+    switch (addr & 0x3ff) {
+    case 0x004: /* EIR */
+        s->eir &= ~value;
+        break;
+    case 0x008: /* EIMR */
+        s->eimr = value;
+        break;
+    case 0x010: /* RDAR */
+        if ((s->ecr & FEC_EN) && !s->rx_enabled) {
+            imx_fec_enable_rx(s);
+        }
+        break;
+    case 0x014: /* TDAR */
+        if (s->ecr & FEC_EN) {
+            imx_fec_do_tx(s);
+        }
+        break;
+    case 0x024: /* ECR */
+        s->ecr = value;
+        if (value & FEC_RESET) {
+            imx_fec_reset(DEVICE(s));
+        }
+        if ((s->ecr & FEC_EN) == 0) {
+            s->rx_enabled = 0;
+        }
+        break;
+    case 0x040: /* MMFR */
+        /* store the value */
+        s->mmfr = value;
+        if (extract32(value, 28, 1)) {
+            do_phy_write(s, extract32(value, 18, 9), extract32(value, 0, 16));
+        } else {
+            s->mmfr = do_phy_read(s, extract32(value, 18, 9));
+        }
+        /* raise the interrupt as the PHY operation is done */
+        s->eir |= FEC_INT_MII;
+        break;
+    case 0x044: /* MSCR */
+        s->mscr = value & 0xfe;
+        break;
+    case 0x064: /* MIBC */
+        /* TODO: Implement MIB.  */
+        s->mibc = (value & 0x80000000) ? 0xc0000000 : 0;
+        break;
+    case 0x084: /* RCR */
+        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->conf.macaddr.a[0] = value >> 24;
+        s->conf.macaddr.a[1] = value >> 16;
+        s->conf.macaddr.a[2] = value >> 8;
+        s->conf.macaddr.a[3] = value;
+        break;
+    case 0x0e8: /* PAUR */
+        s->conf.macaddr.a[4] = value >> 24;
+        s->conf.macaddr.a[5] = value >> 16;
+        break;
+    case 0x0ec: /* OPDR */
+        break;
+    case 0x118: /* IAUR */
+    case 0x11c: /* IALR */
+    case 0x120: /* GAUR */
+    case 0x124: /* GALR */
+        /* TODO: implement MAC hash filtering.  */
+        break;
+    case 0x144: /* TFWR */
+        s->tfwr = value & 3;
+        break;
+    case 0x14c: /* FRBR */
+        /* FRBR writes ignored.  */
+        break;
+    case 0x150: /* FRSR */
+        s->frsr = (value & 0x3fc) | 0x400;
+        break;
+    case 0x180: /* ERDSR */
+        s->erdsr = value & ~3;
+        s->rx_descriptor = s->erdsr;
+        break;
+    case 0x184: /* ETDSR */
+        s->etdsr = value & ~3;
+        s->tx_descriptor = s->etdsr;
+        break;
+    case 0x188: /* EMRBR */
+        s->emrbr = value & 0x7f0;
+        break;
+    case 0x300: /* MIIGSK_CFGR */
+        s->miigsk_cfgr = value & 0x53;
+        break;
+    case 0x308: /* MIIGSK_ENR */
+        s->miigsk_enr = (value & 0x2) ? 0x6 : 0;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Bad address at offset %d\n",
+                      TYPE_IMX_FEC, __func__, (int)addr);
+        break;
+    }
+
+    imx_fec_update(s);
+}
+
+static int imx_fec_can_receive(NetClientState *nc)
+{
+    IMXFECState *s = IMX_FEC(qemu_get_nic_opaque(nc));
+
+    return s->rx_enabled;
+}
+
+static ssize_t imx_fec_receive(NetClientState *nc, const uint8_t *buf,
+                               size_t len)
+{
+    IMXFECState *s = IMX_FEC(qemu_get_nic_opaque(nc));
+    IMXFECBufDesc bd;
+    uint32_t flags = 0;
+    uint32_t addr;
+    uint32_t crc;
+    uint32_t buf_addr;
+    uint8_t *crc_ptr;
+    unsigned int buf_len;
+    size_t size = len;
+
+    FEC_PRINTF("len %d\n", (int)size);
+
+    if (!s->rx_enabled) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Unexpected packet\n",
+                      TYPE_IMX_FEC, __func__);
+        return 0;
+    }
+
+    /* 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) {
+        imx_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.
+             */
+            qemu_log_mask(LOG_GUEST_ERROR, "%s[%s]: Lost end of frame\n",
+                          TYPE_IMX_FEC, __func__);
+            break;
+        }
+        buf_len = (size <= s->emrbr) ? size : s->emrbr;
+        bd.length = buf_len;
+        size -= buf_len;
+        FEC_PRINTF("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;
+        dma_memory_write(&address_space_memory, buf_addr, buf, buf_len);
+        buf += buf_len;
+        if (size < 4) {
+            dma_memory_write(&address_space_memory, 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;
+            FEC_PRINTF("rx frame flags %04x\n", bd.flags);
+            s->eir |= FEC_INT_RXF;
+        } else {
+            s->eir |= FEC_INT_RXB;
+        }
+        imx_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;
+    imx_fec_enable_rx(s);
+    imx_fec_update(s);
+    return len;
+}
+
+static const MemoryRegionOps imx_fec_ops = {
+    .read = imx_fec_read,
+    .write = imx_fec_write,
+    .valid.min_access_size = 4,
+    .valid.max_access_size = 4,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void imx_fec_cleanup(NetClientState *nc)
+{
+    IMXFECState *s = IMX_FEC(qemu_get_nic_opaque(nc));
+
+    s->nic = NULL;
+}
+
+static NetClientInfo net_imx_fec_info = {
+    .type = NET_CLIENT_OPTIONS_KIND_NIC,
+    .size = sizeof(NICState),
+    .can_receive = imx_fec_can_receive,
+    .receive = imx_fec_receive,
+    .cleanup = imx_fec_cleanup,
+    .link_status_changed = imx_fec_set_link,
+};
+
+
+static void imx_fec_realize(DeviceState *dev, Error **errp)
+{
+    IMXFECState *s = IMX_FEC(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+
+    memory_region_init_io(&s->iomem, OBJECT(dev), &imx_fec_ops, s,
+                          TYPE_IMX_FEC, 0x400);
+    sysbus_init_mmio(sbd, &s->iomem);
+    sysbus_init_irq(sbd, &s->irq);
+    qemu_macaddr_default_if_unset(&s->conf.macaddr);
+
+    s->conf.peers.ncs[0] = nd_table[0].netdev;
+
+    s->nic = qemu_new_nic(&net_imx_fec_info, &s->conf,
+                          object_get_typename(OBJECT(dev)), DEVICE(dev)->id,
+                          s);
+    qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
+}
+
+static Property imx_fec_properties[] = {
+    DEFINE_NIC_PROPERTIES(IMXFECState, conf),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void imx_fec_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd = &vmstate_imx_fec;
+    dc->reset = imx_fec_reset;
+    dc->props = imx_fec_properties;
+    dc->realize = imx_fec_realize;
+}
+
+static const TypeInfo imx_fec_info = {
+    .name = TYPE_IMX_FEC,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IMXFECState),
+    .class_init = imx_fec_class_init,
+};
+
+static void imx_fec_register_types(void)
+{
+    type_register_static(&imx_fec_info);
+}
+
+type_init(imx_fec_register_types)
diff --git a/include/hw/net/imx_fec.h b/include/hw/net/imx_fec.h
new file mode 100644
index 0000000..cbf8650
--- /dev/null
+++ b/include/hw/net/imx_fec.h
@@ -0,0 +1,113 @@
+/*
+ * i.MX Fast Ethernet Controller emulation.
+ *
+ * Copyright (c) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net>
+ *
+ * Based on Coldfire Fast Ethernet Controller emulation.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef IMX_FEC_H
+#define IMX_FEC_H
+
+#define TYPE_IMX_FEC "imx.fec"
+#define IMX_FEC(obj) OBJECT_CHECK(IMXFECState, (obj), TYPE_IMX_FEC)
+
+#include "hw/sysbus.h"
+#include "net/net.h"
+
+#define FEC_MAX_FRAME_SIZE 2032
+
+#define FEC_INT_HB      (1 << 31)
+#define FEC_INT_BABR    (1 << 30)
+#define FEC_INT_BABT    (1 << 29)
+#define FEC_INT_GRA     (1 << 28)
+#define FEC_INT_TXF     (1 << 27)
+#define FEC_INT_TXB     (1 << 26)
+#define FEC_INT_RXF     (1 << 25)
+#define FEC_INT_RXB     (1 << 24)
+#define FEC_INT_MII     (1 << 23)
+#define FEC_INT_EBERR   (1 << 22)
+#define FEC_INT_LC      (1 << 21)
+#define FEC_INT_RL      (1 << 20)
+#define FEC_INT_UN      (1 << 19)
+
+#define FEC_EN      2
+#define FEC_RESET   1
+
+/* Buffer Descriptor.  */
+typedef struct {
+    uint16_t length;
+    uint16_t flags;
+    uint32_t data;
+} IMXFECBufDesc;
+
+#define FEC_BD_R    (1 << 15)
+#define FEC_BD_E    (1 << 15)
+#define FEC_BD_O1   (1 << 14)
+#define FEC_BD_W    (1 << 13)
+#define FEC_BD_O2   (1 << 12)
+#define FEC_BD_L    (1 << 11)
+#define FEC_BD_TC   (1 << 10)
+#define FEC_BD_ABC  (1 << 9)
+#define FEC_BD_M    (1 << 8)
+#define FEC_BD_BC   (1 << 7)
+#define FEC_BD_MC   (1 << 6)
+#define FEC_BD_LG   (1 << 5)
+#define FEC_BD_NO   (1 << 4)
+#define FEC_BD_CR   (1 << 2)
+#define FEC_BD_OV   (1 << 1)
+#define FEC_BD_TR   (1 << 0)
+
+typedef struct IMXFECState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    NICState *nic;
+    NICConf conf;
+    qemu_irq irq;
+    MemoryRegion iomem;
+
+    uint32_t irq_state;
+    uint32_t eir;
+    uint32_t eimr;
+    uint32_t rx_enabled;
+    uint32_t rx_descriptor;
+    uint32_t tx_descriptor;
+    uint32_t ecr;
+    uint32_t mmfr;
+    uint32_t mscr;
+    uint32_t mibc;
+    uint32_t rcr;
+    uint32_t tcr;
+    uint32_t tfwr;
+    uint32_t frsr;
+    uint32_t erdsr;
+    uint32_t etdsr;
+    uint32_t emrbr;
+    uint32_t miigsk_cfgr;
+    uint32_t miigsk_enr;
+
+    uint32_t phy_status;
+    uint32_t phy_control;
+    uint32_t phy_advertise;
+    uint32_t phy_int;
+    uint32_t phy_int_mask;
+} IMXFECState;
+
+#endif
-- 
2.1.4