hw/net: Add Smartfusion2 emac block

Modelled Ethernet MAC of Smartfusion2 SoC.
Micrel KSZ8051 PHY is present on Emcraft's
SOM kit hence same PHY is emulated.

Signed-off-by: Subbaraya Sundeep <sundeep.lkml@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1587048891-30493-2-git-send-email-sundeep.lkml@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 645 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 8cbc1fac2b..cea57331fe 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -919,6 +919,8 @@ F: include/hw/arm/msf2-soc.h
 F: include/hw/misc/msf2-sysreg.h
 F: include/hw/timer/mss-timer.h
 F: include/hw/ssi/mss-spi.h
+F: hw/net/msf2-emac.c
+F: include/hw/net/msf2-emac.h
 
 Emcraft M2S-FG484
 M: Subbaraya Sundeep <sundeep.lkml@gmail.com>
diff --git a/hw/net/Makefile.objs b/hw/net/Makefile.objs
index af4d194866..f2b73983ee 100644
--- a/hw/net/Makefile.objs
+++ b/hw/net/Makefile.objs
@@ -55,3 +55,4 @@ common-obj-$(CONFIG_ROCKER) += rocker/rocker.o rocker/rocker_fp.o \
 obj-$(call lnot,$(CONFIG_ROCKER)) += rocker/qmp-norocker.o
 
 common-obj-$(CONFIG_CAN_BUS) += can/
+common-obj-$(CONFIG_MSF2) += msf2-emac.o
diff --git a/hw/net/msf2-emac.c b/hw/net/msf2-emac.c
new file mode 100644
index 0000000000..32ba9e8412
--- /dev/null
+++ b/hw/net/msf2-emac.c
@@ -0,0 +1,589 @@
+/*
+ * QEMU model of the Smartfusion2 Ethernet MAC.
+ *
+ * Copyright (c) 2020 Subbaraya Sundeep <sundeep.lkml@gmail.com>.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * Refer to section Ethernet MAC in the document:
+ * UG0331: SmartFusion2 Microcontroller Subsystem User Guide
+ * Datasheet URL:
+ * https://www.microsemi.com/document-portal/cat_view/56661-internal-documents/
+ * 56758-soc?lang=en&limit=20&limitstart=220
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/log.h"
+#include "qapi/error.h"
+#include "exec/address-spaces.h"
+#include "hw/registerfields.h"
+#include "hw/net/msf2-emac.h"
+#include "hw/net/mii.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+
+REG32(CFG1, 0x0)
+    FIELD(CFG1, RESET, 31, 1)
+    FIELD(CFG1, RX_EN, 2, 1)
+    FIELD(CFG1, TX_EN, 0, 1)
+    FIELD(CFG1, LB_EN, 8, 1)
+REG32(CFG2, 0x4)
+REG32(IFG, 0x8)
+REG32(HALF_DUPLEX, 0xc)
+REG32(MAX_FRAME_LENGTH, 0x10)
+REG32(MII_CMD, 0x24)
+    FIELD(MII_CMD, READ, 0, 1)
+REG32(MII_ADDR, 0x28)
+    FIELD(MII_ADDR, REGADDR, 0, 5)
+    FIELD(MII_ADDR, PHYADDR, 8, 5)
+REG32(MII_CTL, 0x2c)
+REG32(MII_STS, 0x30)
+REG32(STA1, 0x40)
+REG32(STA2, 0x44)
+REG32(FIFO_CFG0, 0x48)
+REG32(FIFO_CFG4, 0x58)
+    FIELD(FIFO_CFG4, BCAST, 9, 1)
+    FIELD(FIFO_CFG4, MCAST, 8, 1)
+REG32(FIFO_CFG5, 0x5C)
+    FIELD(FIFO_CFG5, BCAST, 9, 1)
+    FIELD(FIFO_CFG5, MCAST, 8, 1)
+REG32(DMA_TX_CTL, 0x180)
+    FIELD(DMA_TX_CTL, EN, 0, 1)
+REG32(DMA_TX_DESC, 0x184)
+REG32(DMA_TX_STATUS, 0x188)
+    FIELD(DMA_TX_STATUS, PKTCNT, 16, 8)
+    FIELD(DMA_TX_STATUS, UNDERRUN, 1, 1)
+    FIELD(DMA_TX_STATUS, PKT_SENT, 0, 1)
+REG32(DMA_RX_CTL, 0x18c)
+    FIELD(DMA_RX_CTL, EN, 0, 1)
+REG32(DMA_RX_DESC, 0x190)
+REG32(DMA_RX_STATUS, 0x194)
+    FIELD(DMA_RX_STATUS, PKTCNT, 16, 8)
+    FIELD(DMA_RX_STATUS, OVERFLOW, 2, 1)
+    FIELD(DMA_RX_STATUS, PKT_RCVD, 0, 1)
+REG32(DMA_IRQ_MASK, 0x198)
+REG32(DMA_IRQ, 0x19c)
+
+#define EMPTY_MASK              (1 << 31)
+#define PKT_SIZE                0x7FF
+#define PHYADDR                 0x1
+#define MAX_PKT_SIZE            2048
+
+typedef struct {
+    uint32_t pktaddr;
+    uint32_t pktsize;
+    uint32_t next;
+} EmacDesc;
+
+static uint32_t emac_get_isr(MSF2EmacState *s)
+{
+    uint32_t ier = s->regs[R_DMA_IRQ_MASK];
+    uint32_t tx = s->regs[R_DMA_TX_STATUS] & 0xF;
+    uint32_t rx = s->regs[R_DMA_RX_STATUS] & 0xF;
+    uint32_t isr = (rx << 4) | tx;
+
+    s->regs[R_DMA_IRQ] = ier & isr;
+    return s->regs[R_DMA_IRQ];
+}
+
+static void emac_update_irq(MSF2EmacState *s)
+{
+    bool intr = emac_get_isr(s);
+
+    qemu_set_irq(s->irq, intr);
+}
+
+static void emac_load_desc(MSF2EmacState *s, EmacDesc *d, hwaddr desc)
+{
+    address_space_read(&s->dma_as, desc, MEMTXATTRS_UNSPECIFIED, d, sizeof *d);
+    /* Convert from LE into host endianness. */
+    d->pktaddr = le32_to_cpu(d->pktaddr);
+    d->pktsize = le32_to_cpu(d->pktsize);
+    d->next = le32_to_cpu(d->next);
+}
+
+static void emac_store_desc(MSF2EmacState *s, EmacDesc *d, hwaddr desc)
+{
+    /* Convert from host endianness into LE. */
+    d->pktaddr = cpu_to_le32(d->pktaddr);
+    d->pktsize = cpu_to_le32(d->pktsize);
+    d->next = cpu_to_le32(d->next);
+
+    address_space_write(&s->dma_as, desc, MEMTXATTRS_UNSPECIFIED, d, sizeof *d);
+}
+
+static void msf2_dma_tx(MSF2EmacState *s)
+{
+    NetClientState *nc = qemu_get_queue(s->nic);
+    hwaddr desc = s->regs[R_DMA_TX_DESC];
+    uint8_t buf[MAX_PKT_SIZE];
+    EmacDesc d;
+    int size;
+    uint8_t pktcnt;
+    uint32_t status;
+
+    if (!(s->regs[R_CFG1] & R_CFG1_TX_EN_MASK)) {
+        return;
+    }
+
+    while (1) {
+        emac_load_desc(s, &d, desc);
+        if (d.pktsize & EMPTY_MASK) {
+            break;
+        }
+        size = d.pktsize & PKT_SIZE;
+        address_space_read(&s->dma_as, d.pktaddr, MEMTXATTRS_UNSPECIFIED,
+                           buf, size);
+        /*
+         * This is very basic way to send packets. Ideally there should be
+         * a FIFO and packets should be sent out from FIFO only when
+         * R_CFG1 bit 0 is set.
+         */
+        if (s->regs[R_CFG1] & R_CFG1_LB_EN_MASK) {
+            nc->info->receive(nc, buf, size);
+        } else {
+            qemu_send_packet(nc, buf, size);
+        }
+        d.pktsize |= EMPTY_MASK;
+        emac_store_desc(s, &d, desc);
+        /* update sent packets count */
+        status = s->regs[R_DMA_TX_STATUS];
+        pktcnt = FIELD_EX32(status, DMA_TX_STATUS, PKTCNT);
+        pktcnt++;
+        s->regs[R_DMA_TX_STATUS] = FIELD_DP32(status, DMA_TX_STATUS,
+                                              PKTCNT, pktcnt);
+        s->regs[R_DMA_TX_STATUS] |= R_DMA_TX_STATUS_PKT_SENT_MASK;
+        desc = d.next;
+    }
+    s->regs[R_DMA_TX_STATUS] |= R_DMA_TX_STATUS_UNDERRUN_MASK;
+    s->regs[R_DMA_TX_CTL] &= ~R_DMA_TX_CTL_EN_MASK;
+}
+
+static void msf2_phy_update_link(MSF2EmacState *s)
+{
+    /* Autonegotiation status mirrors link status. */
+    if (qemu_get_queue(s->nic)->link_down) {
+        s->phy_regs[MII_BMSR] &= ~(MII_BMSR_AN_COMP |
+                                   MII_BMSR_LINK_ST);
+    } else {
+        s->phy_regs[MII_BMSR] |= (MII_BMSR_AN_COMP |
+                                  MII_BMSR_LINK_ST);
+    }
+}
+
+static void msf2_phy_reset(MSF2EmacState *s)
+{
+    memset(&s->phy_regs[0], 0, sizeof(s->phy_regs));
+    s->phy_regs[MII_BMCR] = 0x1140;
+    s->phy_regs[MII_BMSR] = 0x7968;
+    s->phy_regs[MII_PHYID1] = 0x0022;
+    s->phy_regs[MII_PHYID2] = 0x1550;
+    s->phy_regs[MII_ANAR] = 0x01E1;
+    s->phy_regs[MII_ANLPAR] = 0xCDE1;
+
+    msf2_phy_update_link(s);
+}
+
+static void write_to_phy(MSF2EmacState *s)
+{
+    uint8_t reg_addr = s->regs[R_MII_ADDR] & R_MII_ADDR_REGADDR_MASK;
+    uint8_t phy_addr = (s->regs[R_MII_ADDR] >> R_MII_ADDR_PHYADDR_SHIFT) &
+                       R_MII_ADDR_REGADDR_MASK;
+    uint16_t data = s->regs[R_MII_CTL] & 0xFFFF;
+
+    if (phy_addr != PHYADDR) {
+        return;
+    }
+
+    switch (reg_addr) {
+    case MII_BMCR:
+        if (data & MII_BMCR_RESET) {
+            /* Phy reset */
+            msf2_phy_reset(s);
+            data &= ~MII_BMCR_RESET;
+        }
+        if (data & MII_BMCR_AUTOEN) {
+            /* Complete autonegotiation immediately */
+            data &= ~MII_BMCR_AUTOEN;
+            s->phy_regs[MII_BMSR] |= MII_BMSR_AN_COMP;
+        }
+        break;
+    }
+
+    s->phy_regs[reg_addr] = data;
+}
+
+static uint16_t read_from_phy(MSF2EmacState *s)
+{
+    uint8_t reg_addr = s->regs[R_MII_ADDR] & R_MII_ADDR_REGADDR_MASK;
+    uint8_t phy_addr = (s->regs[R_MII_ADDR] >> R_MII_ADDR_PHYADDR_SHIFT) &
+                       R_MII_ADDR_REGADDR_MASK;
+
+    if (phy_addr == PHYADDR) {
+        return s->phy_regs[reg_addr];
+    } else {
+        return 0xFFFF;
+    }
+}
+
+static void msf2_emac_do_reset(MSF2EmacState *s)
+{
+    memset(&s->regs[0], 0, sizeof(s->regs));
+    s->regs[R_CFG1] = 0x80000000;
+    s->regs[R_CFG2] = 0x00007000;
+    s->regs[R_IFG] = 0x40605060;
+    s->regs[R_HALF_DUPLEX] = 0x00A1F037;
+    s->regs[R_MAX_FRAME_LENGTH] = 0x00000600;
+    s->regs[R_FIFO_CFG5] = 0X3FFFF;
+
+    msf2_phy_reset(s);
+}
+
+static uint64_t emac_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    MSF2EmacState *s = opaque;
+    uint32_t r = 0;
+
+    addr >>= 2;
+
+    switch (addr) {
+    case R_DMA_IRQ:
+        r = emac_get_isr(s);
+        break;
+    default:
+        if (addr >= ARRAY_SIZE(s->regs)) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__,
+                          addr * 4);
+            return r;
+        }
+        r = s->regs[addr];
+        break;
+    }
+    return r;
+}
+
+static void emac_write(void *opaque, hwaddr addr, uint64_t val64,
+        unsigned int size)
+{
+    MSF2EmacState *s = opaque;
+    uint32_t value = val64;
+    uint32_t enreqbits;
+    uint8_t pktcnt;
+
+    addr >>= 2;
+    switch (addr) {
+    case R_DMA_TX_CTL:
+        s->regs[addr] = value;
+        if (value & R_DMA_TX_CTL_EN_MASK) {
+            msf2_dma_tx(s);
+        }
+        break;
+    case R_DMA_RX_CTL:
+        s->regs[addr] = value;
+        if (value & R_DMA_RX_CTL_EN_MASK) {
+            s->rx_desc = s->regs[R_DMA_RX_DESC];
+            qemu_flush_queued_packets(qemu_get_queue(s->nic));
+        }
+        break;
+    case R_CFG1:
+        s->regs[addr] = value;
+        if (value & R_CFG1_RESET_MASK) {
+            msf2_emac_do_reset(s);
+        }
+        break;
+    case R_FIFO_CFG0:
+       /*
+        * For our implementation, turning on modules is instantaneous,
+        * so the states requested via the *ENREQ bits appear in the
+        * *ENRPLY bits immediately. Also the reset bits to reset PE-MCXMAC
+        * module are not emulated here since it deals with start of frames,
+        * inter-packet gap and control frames.
+        */
+        enreqbits = extract32(value, 8, 5);
+        s->regs[addr] = deposit32(value, 16, 5, enreqbits);
+        break;
+    case R_DMA_TX_DESC:
+        if (value & 0x3) {
+            qemu_log_mask(LOG_GUEST_ERROR, "Tx Descriptor address should be"
+                          " 32 bit aligned\n");
+        }
+        /* Ignore [1:0] bits */
+        s->regs[addr] = value & ~3;
+        break;
+    case R_DMA_RX_DESC:
+        if (value & 0x3) {
+            qemu_log_mask(LOG_GUEST_ERROR, "Rx Descriptor address should be"
+                          " 32 bit aligned\n");
+        }
+        /* Ignore [1:0] bits */
+        s->regs[addr] = value & ~3;
+        break;
+    case R_DMA_TX_STATUS:
+        if (value & R_DMA_TX_STATUS_UNDERRUN_MASK) {
+            s->regs[addr] &= ~R_DMA_TX_STATUS_UNDERRUN_MASK;
+        }
+        if (value & R_DMA_TX_STATUS_PKT_SENT_MASK) {
+            pktcnt = FIELD_EX32(s->regs[addr], DMA_TX_STATUS, PKTCNT);
+            pktcnt--;
+            s->regs[addr] = FIELD_DP32(s->regs[addr], DMA_TX_STATUS,
+                                       PKTCNT, pktcnt);
+            if (pktcnt == 0) {
+                s->regs[addr] &= ~R_DMA_TX_STATUS_PKT_SENT_MASK;
+            }
+        }
+        break;
+    case R_DMA_RX_STATUS:
+        if (value & R_DMA_RX_STATUS_OVERFLOW_MASK) {
+            s->regs[addr] &= ~R_DMA_RX_STATUS_OVERFLOW_MASK;
+        }
+        if (value & R_DMA_RX_STATUS_PKT_RCVD_MASK) {
+            pktcnt = FIELD_EX32(s->regs[addr], DMA_RX_STATUS, PKTCNT);
+            pktcnt--;
+            s->regs[addr] = FIELD_DP32(s->regs[addr], DMA_RX_STATUS,
+                                       PKTCNT, pktcnt);
+            if (pktcnt == 0) {
+                s->regs[addr] &= ~R_DMA_RX_STATUS_PKT_RCVD_MASK;
+            }
+        }
+        break;
+    case R_DMA_IRQ:
+        break;
+    case R_MII_CMD:
+        if (value & R_MII_CMD_READ_MASK) {
+            s->regs[R_MII_STS] = read_from_phy(s);
+        }
+        break;
+    case R_MII_CTL:
+        s->regs[addr] = value;
+        write_to_phy(s);
+        break;
+    case R_STA1:
+        s->regs[addr] = value;
+       /*
+        * R_STA1 [31:24] : octet 1 of mac address
+        * R_STA1 [23:16] : octet 2 of mac address
+        * R_STA1 [15:8] : octet 3 of mac address
+        * R_STA1 [7:0] : octet 4 of mac address
+        */
+        stl_be_p(s->mac_addr, value);
+        break;
+    case R_STA2:
+        s->regs[addr] = value;
+       /*
+        * R_STA2 [31:24] : octet 5 of mac address
+        * R_STA2 [23:16] : octet 6 of mac address
+        */
+        stw_be_p(s->mac_addr + 4, value >> 16);
+        break;
+    default:
+        if (addr >= ARRAY_SIZE(s->regs)) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__,
+                          addr * 4);
+            return;
+        }
+        s->regs[addr] = value;
+        break;
+    }
+    emac_update_irq(s);
+}
+
+static const MemoryRegionOps emac_ops = {
+    .read = emac_read,
+    .write = emac_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 4
+    }
+};
+
+static bool emac_can_rx(NetClientState *nc)
+{
+    MSF2EmacState *s = qemu_get_nic_opaque(nc);
+
+    return (s->regs[R_CFG1] & R_CFG1_RX_EN_MASK) &&
+           (s->regs[R_DMA_RX_CTL] & R_DMA_RX_CTL_EN_MASK);
+}
+
+static bool addr_filter_ok(MSF2EmacState *s, const uint8_t *buf)
+{
+    /* The broadcast MAC address: FF:FF:FF:FF:FF:FF */
+    const uint8_t broadcast_addr[] = { 0xFF, 0xFF, 0xFF, 0xFF,
+                                              0xFF, 0xFF };
+    bool bcast_en = true;
+    bool mcast_en = true;
+
+    if (s->regs[R_FIFO_CFG5] & R_FIFO_CFG5_BCAST_MASK) {
+        bcast_en = true; /* Broadcast dont care for drop circuitry */
+    } else if (s->regs[R_FIFO_CFG4] & R_FIFO_CFG4_BCAST_MASK) {
+        bcast_en = false;
+    }
+
+    if (s->regs[R_FIFO_CFG5] & R_FIFO_CFG5_MCAST_MASK) {
+        mcast_en = true; /* Multicast dont care for drop circuitry */
+    } else if (s->regs[R_FIFO_CFG4] & R_FIFO_CFG4_MCAST_MASK) {
+        mcast_en = false;
+    }
+
+    if (!memcmp(buf, broadcast_addr, sizeof(broadcast_addr))) {
+        return bcast_en;
+    }
+
+    if (buf[0] & 1) {
+        return mcast_en;
+    }
+
+    return !memcmp(buf, s->mac_addr, sizeof(s->mac_addr));
+}
+
+static ssize_t emac_rx(NetClientState *nc, const uint8_t *buf, size_t size)
+{
+    MSF2EmacState *s = qemu_get_nic_opaque(nc);
+    EmacDesc d;
+    uint8_t pktcnt;
+    uint32_t status;
+
+    if (size > (s->regs[R_MAX_FRAME_LENGTH] & 0xFFFF)) {
+        return size;
+    }
+    if (!addr_filter_ok(s, buf)) {
+        return size;
+    }
+
+    emac_load_desc(s, &d, s->rx_desc);
+
+    if (d.pktsize & EMPTY_MASK) {
+        address_space_write(&s->dma_as, d.pktaddr, MEMTXATTRS_UNSPECIFIED,
+                            buf, size & PKT_SIZE);
+        d.pktsize = size & PKT_SIZE;
+        emac_store_desc(s, &d, s->rx_desc);
+        /* update received packets count */
+        status = s->regs[R_DMA_RX_STATUS];
+        pktcnt = FIELD_EX32(status, DMA_RX_STATUS, PKTCNT);
+        pktcnt++;
+        s->regs[R_DMA_RX_STATUS] = FIELD_DP32(status, DMA_RX_STATUS,
+                                              PKTCNT, pktcnt);
+        s->regs[R_DMA_RX_STATUS] |= R_DMA_RX_STATUS_PKT_RCVD_MASK;
+        s->rx_desc = d.next;
+    } else {
+        s->regs[R_DMA_RX_CTL] &= ~R_DMA_RX_CTL_EN_MASK;
+        s->regs[R_DMA_RX_STATUS] |= R_DMA_RX_STATUS_OVERFLOW_MASK;
+    }
+    emac_update_irq(s);
+    return size;
+}
+
+static void msf2_emac_reset(DeviceState *dev)
+{
+    MSF2EmacState *s = MSS_EMAC(dev);
+
+    msf2_emac_do_reset(s);
+}
+
+static void emac_set_link(NetClientState *nc)
+{
+    MSF2EmacState *s = qemu_get_nic_opaque(nc);
+
+    msf2_phy_update_link(s);
+}
+
+static NetClientInfo net_msf2_emac_info = {
+    .type = NET_CLIENT_DRIVER_NIC,
+    .size = sizeof(NICState),
+    .can_receive = emac_can_rx,
+    .receive = emac_rx,
+    .link_status_changed = emac_set_link,
+};
+
+static void msf2_emac_realize(DeviceState *dev, Error **errp)
+{
+    MSF2EmacState *s = MSS_EMAC(dev);
+
+    if (!s->dma_mr) {
+        error_setg(errp, "MSS_EMAC 'ahb-bus' link not set");
+        return;
+    }
+
+    address_space_init(&s->dma_as, s->dma_mr, "emac-ahb");
+
+    qemu_macaddr_default_if_unset(&s->conf.macaddr);
+    s->nic = qemu_new_nic(&net_msf2_emac_info, &s->conf,
+                          object_get_typename(OBJECT(dev)), dev->id, s);
+    qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
+}
+
+static void msf2_emac_init(Object *obj)
+{
+    MSF2EmacState *s = MSS_EMAC(obj);
+
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
+
+    memory_region_init_io(&s->mmio, obj, &emac_ops, s,
+                          "msf2-emac", R_MAX * 4);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+
+static Property msf2_emac_properties[] = {
+    DEFINE_PROP_LINK("ahb-bus", MSF2EmacState, dma_mr,
+                     TYPE_MEMORY_REGION, MemoryRegion *),
+    DEFINE_NIC_PROPERTIES(MSF2EmacState, conf),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static const VMStateDescription vmstate_msf2_emac = {
+    .name = TYPE_MSS_EMAC,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8_ARRAY(mac_addr, MSF2EmacState, ETH_ALEN),
+        VMSTATE_UINT32(rx_desc, MSF2EmacState),
+        VMSTATE_UINT16_ARRAY(phy_regs, MSF2EmacState, PHY_MAX_REGS),
+        VMSTATE_UINT32_ARRAY(regs, MSF2EmacState, R_MAX),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void msf2_emac_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = msf2_emac_realize;
+    dc->reset = msf2_emac_reset;
+    dc->vmsd = &vmstate_msf2_emac;
+    device_class_set_props(dc, msf2_emac_properties);
+}
+
+static const TypeInfo msf2_emac_info = {
+    .name          = TYPE_MSS_EMAC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(MSF2EmacState),
+    .instance_init = msf2_emac_init,
+    .class_init    = msf2_emac_class_init,
+};
+
+static void msf2_emac_register_types(void)
+{
+    type_register_static(&msf2_emac_info);
+}
+
+type_init(msf2_emac_register_types)
diff --git a/include/hw/net/msf2-emac.h b/include/hw/net/msf2-emac.h
new file mode 100644
index 0000000000..37966d3a81
--- /dev/null
+++ b/include/hw/net/msf2-emac.h
@@ -0,0 +1,53 @@
+/*
+ * QEMU model of the Smartfusion2 Ethernet MAC.
+ *
+ * Copyright (c) 2020 Subbaraya Sundeep <sundeep.lkml@gmail.com>.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw/sysbus.h"
+#include "exec/memory.h"
+#include "net/net.h"
+#include "net/eth.h"
+
+#define TYPE_MSS_EMAC "msf2-emac"
+#define MSS_EMAC(obj) \
+    OBJECT_CHECK(MSF2EmacState, (obj), TYPE_MSS_EMAC)
+
+#define R_MAX         (0x1a0 / 4)
+#define PHY_MAX_REGS  32
+
+typedef struct MSF2EmacState {
+    SysBusDevice parent;
+
+    MemoryRegion mmio;
+    MemoryRegion *dma_mr;
+    AddressSpace dma_as;
+
+    qemu_irq irq;
+    NICState *nic;
+    NICConf conf;
+
+    uint8_t mac_addr[ETH_ALEN];
+    uint32_t rx_desc;
+    uint16_t phy_regs[PHY_MAX_REGS];
+
+    uint32_t regs[R_MAX];
+} MSF2EmacState;