hw/net: add support for Allwinner EMAC Fast Ethernet controller

This patch adds support for the Fast Ethernet MAC found on Allwinner
SoCs, together with a basic emulation of Realtek RTL8201CP PHY.

Since there is no public documentation of the Allwinner controller, the
implementation is based on Linux kernel driver.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 540 insertions, 0 deletions

diff --git a/hw/net/Makefile.objs b/hw/net/Makefile.objs
index 951cca3..75e80c2 100644
--- a/hw/net/Makefile.objs
+++ b/hw/net/Makefile.objs
@@ -18,6 +18,7 @@ common-obj-$(CONFIG_OPENCORES_ETH) += opencores_eth.o
 common-obj-$(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-$(CONFIG_CADENCE) += cadence_gem.o
 common-obj-$(CONFIG_STELLARIS_ENET) += stellaris_enet.o
diff --git a/hw/net/allwinner_emac.c b/hw/net/allwinner_emac.c
new file mode 100644
index 0000000..469f2f0
--- /dev/null
+++ b/hw/net/allwinner_emac.c
@@ -0,0 +1,539 @@
+/*
+ * Emulation of Allwinner EMAC Fast Ethernet controller and
+ * Realtek RTL8201CP PHY
+ *
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
+ *
+ * This model is based on reverse-engineering of Linux kernel driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ */
+#include "hw/sysbus.h"
+#include "net/net.h"
+#include "qemu/fifo8.h"
+#include "hw/net/allwinner_emac.h"
+#include <zlib.h>
+
+static uint8_t padding[60];
+
+static void mii_set_link(RTL8201CPState *mii, bool link_ok)
+{
+    if (link_ok) {
+        mii->bmsr |= MII_BMSR_LINK_ST;
+        mii->anlpar |= MII_ANAR_TXFD | MII_ANAR_10FD | MII_ANAR_10 |
+                       MII_ANAR_CSMACD;
+    } else {
+        mii->bmsr &= ~MII_BMSR_LINK_ST;
+        mii->anlpar = MII_ANAR_TX;
+    }
+}
+
+static void mii_reset(RTL8201CPState *mii, bool link_ok)
+{
+    mii->bmcr = MII_BMCR_FD | MII_BMCR_AUTOEN | MII_BMCR_SPEED;
+    mii->bmsr = MII_BMSR_100TX_FD | MII_BMSR_100TX_HD | MII_BMSR_10T_FD |
+                MII_BMSR_10T_HD | MII_BMSR_MFPS | MII_BMSR_AUTONEG;
+    mii->anar = MII_ANAR_TXFD | MII_ANAR_TX | MII_ANAR_10FD | MII_ANAR_10 |
+                MII_ANAR_CSMACD;
+    mii->anlpar = MII_ANAR_TX;
+
+    mii_set_link(mii, link_ok);
+}
+
+static uint16_t RTL8201CP_mdio_read(AwEmacState *s, uint8_t addr, uint8_t reg)
+{
+    RTL8201CPState *mii = &s->mii;
+    uint16_t ret = 0xffff;
+
+    if (addr == s->phy_addr) {
+        switch (reg) {
+        case MII_BMCR:
+            return mii->bmcr;
+        case MII_BMSR:
+            return mii->bmsr;
+        case MII_PHYID1:
+            return RTL8201CP_PHYID1;
+        case MII_PHYID2:
+            return RTL8201CP_PHYID2;
+        case MII_ANAR:
+            return mii->anar;
+        case MII_ANLPAR:
+            return mii->anlpar;
+        case MII_ANER:
+        case MII_NSR:
+        case MII_LBREMR:
+        case MII_REC:
+        case MII_SNRDR:
+        case MII_TEST:
+            qemu_log_mask(LOG_UNIMP,
+                          "allwinner_emac: read from unimpl. mii reg 0x%x\n",
+                          reg);
+            return 0;
+        default:
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "allwinner_emac: read from invalid mii reg 0x%x\n",
+                          reg);
+            return 0;
+        }
+    }
+    return ret;
+}
+
+static void RTL8201CP_mdio_write(AwEmacState *s, uint8_t addr, uint8_t reg,
+                                 uint16_t value)
+{
+    RTL8201CPState *mii = &s->mii;
+    NetClientState *nc;
+
+    if (addr == s->phy_addr) {
+        switch (reg) {
+        case MII_BMCR:
+            if (value & MII_BMCR_RESET) {
+                nc = qemu_get_queue(s->nic);
+                mii_reset(mii, !nc->link_down);
+            } else {
+                mii->bmcr = value;
+            }
+            break;
+        case MII_ANAR:
+            mii->anar = value;
+            break;
+        case MII_BMSR:
+        case MII_PHYID1:
+        case MII_PHYID2:
+        case MII_ANLPAR:
+        case MII_ANER:
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "allwinner_emac: write to read-only mii reg 0x%x\n",
+                          reg);
+            break;
+        case MII_NSR:
+        case MII_LBREMR:
+        case MII_REC:
+        case MII_SNRDR:
+        case MII_TEST:
+            qemu_log_mask(LOG_UNIMP,
+                          "allwinner_emac: write to unimpl. mii reg 0x%x\n",
+                          reg);
+            break;
+        default:
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "allwinner_emac: write to invalid mii reg 0x%x\n",
+                          reg);
+        }
+    }
+}
+
+static void aw_emac_update_irq(AwEmacState *s)
+{
+    qemu_set_irq(s->irq, (s->int_sta & s->int_ctl) != 0);
+}
+
+static void aw_emac_tx_reset(AwEmacState *s, int chan)
+{
+    fifo8_reset(&s->tx_fifo[chan]);
+    s->tx_length[chan] = 0;
+}
+
+static void aw_emac_rx_reset(AwEmacState *s)
+{
+    fifo8_reset(&s->rx_fifo);
+    s->rx_num_packets = 0;
+    s->rx_packet_size = 0;
+    s->rx_packet_pos = 0;
+}
+
+static void fifo8_push_word(Fifo8 *fifo, uint32_t val)
+{
+    fifo8_push(fifo, val);
+    fifo8_push(fifo, val >> 8);
+    fifo8_push(fifo, val >> 16);
+    fifo8_push(fifo, val >> 24);
+}
+
+static uint32_t fifo8_pop_word(Fifo8 *fifo)
+{
+    uint32_t ret;
+
+    ret = fifo8_pop(fifo);
+    ret |= fifo8_pop(fifo) << 8;
+    ret |= fifo8_pop(fifo) << 16;
+    ret |= fifo8_pop(fifo) << 24;
+
+    return ret;
+}
+
+static int aw_emac_can_receive(NetClientState *nc)
+{
+    AwEmacState *s = qemu_get_nic_opaque(nc);
+
+    /*
+     * To avoid packet drops, allow reception only when there is space
+     * for a full frame: 1522 + 8 (rx headers) + 2 (padding).
+     */
+    return (s->ctl & EMAC_CTL_RX_EN) && (fifo8_num_free(&s->rx_fifo) >= 1532);
+}
+
+static ssize_t aw_emac_receive(NetClientState *nc, const uint8_t *buf,
+                               size_t size)
+{
+    AwEmacState *s = qemu_get_nic_opaque(nc);
+    Fifo8 *fifo = &s->rx_fifo;
+    size_t padded_size, total_size;
+    uint32_t crc;
+
+    padded_size = size > 60 ? size : 60;
+    total_size = QEMU_ALIGN_UP(RX_HDR_SIZE + padded_size + CRC_SIZE, 4);
+
+    if (!(s->ctl & EMAC_CTL_RX_EN) || (fifo8_num_free(fifo) < total_size)) {
+        return -1;
+    }
+
+    fifo8_push_word(fifo, EMAC_UNDOCUMENTED_MAGIC);
+    fifo8_push_word(fifo, EMAC_RX_HEADER(padded_size + CRC_SIZE,
+                                         EMAC_RX_IO_DATA_STATUS_OK));
+    fifo8_push_all(fifo, buf, size);
+    crc = crc32(~0, buf, size);
+
+    if (padded_size != size) {
+        fifo8_push_all(fifo, padding, padded_size - size);
+        crc = crc32(crc, padding, padded_size - size);
+    }
+
+    fifo8_push_word(fifo, crc);
+    fifo8_push_all(fifo, padding, QEMU_ALIGN_UP(padded_size, 4) - padded_size);
+    s->rx_num_packets++;
+
+    s->int_sta |= EMAC_INT_RX;
+    aw_emac_update_irq(s);
+
+    return size;
+}
+
+static void aw_emac_cleanup(NetClientState *nc)
+{
+    AwEmacState *s = qemu_get_nic_opaque(nc);
+
+    s->nic = NULL;
+}
+
+static void aw_emac_reset(DeviceState *dev)
+{
+    AwEmacState *s = AW_EMAC(dev);
+    NetClientState *nc = qemu_get_queue(s->nic);
+
+    s->ctl = 0;
+    s->tx_mode = 0;
+    s->int_ctl = 0;
+    s->int_sta = 0;
+    s->tx_channel = 0;
+    s->phy_target = 0;
+
+    aw_emac_tx_reset(s, 0);
+    aw_emac_tx_reset(s, 1);
+    aw_emac_rx_reset(s);
+
+    mii_reset(&s->mii, !nc->link_down);
+}
+
+static uint64_t aw_emac_read(void *opaque, hwaddr offset, unsigned size)
+{
+    AwEmacState *s = opaque;
+    Fifo8 *fifo = &s->rx_fifo;
+    NetClientState *nc;
+    uint64_t ret;
+
+    switch (offset) {
+    case EMAC_CTL_REG:
+        return s->ctl;
+    case EMAC_TX_MODE_REG:
+        return s->tx_mode;
+    case EMAC_TX_INS_REG:
+        return s->tx_channel;
+    case EMAC_RX_CTL_REG:
+        return s->rx_ctl;
+    case EMAC_RX_IO_DATA_REG:
+        if (!s->rx_num_packets) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "Read IO data register when no packet available");
+            return 0;
+        }
+
+        ret = fifo8_pop_word(fifo);
+
+        switch (s->rx_packet_pos) {
+        case 0:     /* Word is magic header */
+            s->rx_packet_pos += 4;
+            break;
+        case 4:     /* Word is rx info header */
+            s->rx_packet_pos += 4;
+            s->rx_packet_size = QEMU_ALIGN_UP(extract32(ret, 0, 16), 4);
+            break;
+        default:    /* Word is packet data */
+            s->rx_packet_pos += 4;
+            s->rx_packet_size -= 4;
+
+            if (!s->rx_packet_size) {
+                s->rx_packet_pos = 0;
+                s->rx_num_packets--;
+                nc = qemu_get_queue(s->nic);
+                if (aw_emac_can_receive(nc)) {
+                    qemu_flush_queued_packets(nc);
+                }
+            }
+        }
+        return ret;
+    case EMAC_RX_FBC_REG:
+        return s->rx_num_packets;
+    case EMAC_INT_CTL_REG:
+        return s->int_ctl;
+    case EMAC_INT_STA_REG:
+        return s->int_sta;
+    case EMAC_MAC_MRDD_REG:
+        return RTL8201CP_mdio_read(s,
+                                   extract32(s->phy_target, PHY_ADDR_SHIFT, 8),
+                                   extract32(s->phy_target, PHY_REG_SHIFT, 8));
+    default:
+        qemu_log_mask(LOG_UNIMP,
+                      "allwinner_emac: read access to unknown register 0x"
+                      TARGET_FMT_plx "\n", offset);
+        ret = 0;
+    }
+
+    return ret;
+}
+
+static void aw_emac_write(void *opaque, hwaddr offset, uint64_t value,
+                          unsigned size)
+{
+    AwEmacState *s = opaque;
+    Fifo8 *fifo;
+    NetClientState *nc = qemu_get_queue(s->nic);
+    int chan;
+
+    switch (offset) {
+    case EMAC_CTL_REG:
+        if (value & EMAC_CTL_RESET) {
+            aw_emac_reset(DEVICE(s));
+            value &= ~EMAC_CTL_RESET;
+        }
+        s->ctl = value;
+        if (aw_emac_can_receive(nc)) {
+            qemu_flush_queued_packets(nc);
+        }
+        break;
+    case EMAC_TX_MODE_REG:
+        s->tx_mode = value;
+        break;
+    case EMAC_TX_CTL0_REG:
+    case EMAC_TX_CTL1_REG:
+        chan = (offset == EMAC_TX_CTL0_REG ? 0 : 1);
+        if ((value & 1) && (s->ctl & EMAC_CTL_TX_EN)) {
+            uint32_t len, ret;
+            const uint8_t *data;
+
+            fifo = &s->tx_fifo[chan];
+            len = s->tx_length[chan];
+
+            if (len > fifo8_num_used(fifo)) {
+                len = fifo8_num_used(fifo);
+                qemu_log_mask(LOG_GUEST_ERROR,
+                              "allwinner_emac: TX length > fifo data length\n");
+            }
+            if (len > 0) {
+                data = fifo8_pop_buf(fifo, len, &ret);
+                qemu_send_packet(nc, data, ret);
+                aw_emac_tx_reset(s, chan);
+                /* Raise TX interrupt */
+                s->int_sta |= EMAC_INT_TX_CHAN(chan);
+                aw_emac_update_irq(s);
+            }
+        }
+        break;
+    case EMAC_TX_INS_REG:
+        s->tx_channel = value < NUM_TX_FIFOS ? value : 0;
+        break;
+    case EMAC_TX_PL0_REG:
+    case EMAC_TX_PL1_REG:
+        chan = (offset == EMAC_TX_PL0_REG ? 0 : 1);
+        if (value > TX_FIFO_SIZE) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "allwinner_emac: invalid TX frame length %d\n",
+                          (int)value);
+            value = TX_FIFO_SIZE;
+        }
+        s->tx_length[chan] = value;
+        break;
+    case EMAC_TX_IO_DATA_REG:
+        fifo = &s->tx_fifo[s->tx_channel];
+        if (fifo8_num_free(fifo) < 4) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "allwinner_emac: TX data overruns fifo\n");
+            break;
+        }
+        fifo8_push_word(fifo, value);
+        break;
+    case EMAC_RX_CTL_REG:
+        s->rx_ctl = value;
+        break;
+    case EMAC_RX_FBC_REG:
+        if (value == 0) {
+            aw_emac_rx_reset(s);
+        }
+        break;
+    case EMAC_INT_CTL_REG:
+        s->int_ctl = value;
+        break;
+    case EMAC_INT_STA_REG:
+        s->int_sta &= ~value;
+        break;
+    case EMAC_MAC_MADR_REG:
+        s->phy_target = value;
+        break;
+    case EMAC_MAC_MWTD_REG:
+        RTL8201CP_mdio_write(s, extract32(s->phy_target, PHY_ADDR_SHIFT, 8),
+                             extract32(s->phy_target, PHY_REG_SHIFT, 8), value);
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP,
+                      "allwinner_emac: write access to unknown register 0x"
+                      TARGET_FMT_plx "\n", offset);
+    }
+}
+
+static void aw_emac_set_link(NetClientState *nc)
+{
+    AwEmacState *s = qemu_get_nic_opaque(nc);
+
+    mii_set_link(&s->mii, !nc->link_down);
+}
+
+static const MemoryRegionOps aw_emac_mem_ops = {
+    .read = aw_emac_read,
+    .write = aw_emac_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+};
+
+static NetClientInfo net_aw_emac_info = {
+    .type = NET_CLIENT_OPTIONS_KIND_NIC,
+    .size = sizeof(NICState),
+    .can_receive = aw_emac_can_receive,
+    .receive = aw_emac_receive,
+    .cleanup = aw_emac_cleanup,
+    .link_status_changed = aw_emac_set_link,
+};
+
+static void aw_emac_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    AwEmacState *s = AW_EMAC(obj);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &aw_emac_mem_ops, s,
+                          "aw_emac", 0x1000);
+    sysbus_init_mmio(sbd, &s->iomem);
+    sysbus_init_irq(sbd, &s->irq);
+}
+
+static void aw_emac_realize(DeviceState *dev, Error **errp)
+{
+    AwEmacState *s = AW_EMAC(dev);
+
+    qemu_macaddr_default_if_unset(&s->conf.macaddr);
+    s->nic = qemu_new_nic(&net_aw_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);
+
+    fifo8_create(&s->rx_fifo, RX_FIFO_SIZE);
+    fifo8_create(&s->tx_fifo[0], TX_FIFO_SIZE);
+    fifo8_create(&s->tx_fifo[1], TX_FIFO_SIZE);
+}
+
+static Property aw_emac_properties[] = {
+    DEFINE_NIC_PROPERTIES(AwEmacState, conf),
+    DEFINE_PROP_UINT8("phy-addr", AwEmacState, phy_addr, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static const VMStateDescription vmstate_mii = {
+    .name = "rtl8201cp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT16(bmcr, RTL8201CPState),
+        VMSTATE_UINT16(bmsr, RTL8201CPState),
+        VMSTATE_UINT16(anar, RTL8201CPState),
+        VMSTATE_UINT16(anlpar, RTL8201CPState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static int aw_emac_post_load(void *opaque, int version_id)
+{
+    AwEmacState *s = opaque;
+
+    aw_emac_set_link(qemu_get_queue(s->nic));
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_aw_emac = {
+    .name = "allwinner_emac",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .post_load = aw_emac_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT(mii, AwEmacState, 1, vmstate_mii, RTL8201CPState),
+        VMSTATE_UINT32(ctl, AwEmacState),
+        VMSTATE_UINT32(tx_mode, AwEmacState),
+        VMSTATE_UINT32(rx_ctl, AwEmacState),
+        VMSTATE_UINT32(int_ctl, AwEmacState),
+        VMSTATE_UINT32(int_sta, AwEmacState),
+        VMSTATE_UINT32(phy_target, AwEmacState),
+        VMSTATE_FIFO8(rx_fifo, AwEmacState),
+        VMSTATE_UINT32(rx_num_packets, AwEmacState),
+        VMSTATE_UINT32(rx_packet_size, AwEmacState),
+        VMSTATE_UINT32(rx_packet_pos, AwEmacState),
+        VMSTATE_STRUCT_ARRAY(tx_fifo, AwEmacState, NUM_TX_FIFOS, 1,
+                             vmstate_fifo8, Fifo8),
+        VMSTATE_UINT32_ARRAY(tx_length, AwEmacState, NUM_TX_FIFOS),
+        VMSTATE_UINT32(tx_channel, AwEmacState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void aw_emac_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = aw_emac_realize;
+    dc->props = aw_emac_properties;
+    dc->reset = aw_emac_reset;
+    dc->vmsd = &vmstate_aw_emac;
+}
+
+static const TypeInfo aw_emac_info = {
+    .name           = TYPE_AW_EMAC,
+    .parent         = TYPE_SYS_BUS_DEVICE,
+    .instance_size  = sizeof(AwEmacState),
+    .instance_init   = aw_emac_init,
+    .class_init     = aw_emac_class_init,
+};
+
+static void aw_emac_register_types(void)
+{
+    type_register_static(&aw_emac_info);
+}
+
+type_init(aw_emac_register_types)