hw/net/sunhme.c

/*
 * QEMU Sun Happy Meal Ethernet emulation
 *
 * Copyright (c) 2017 Mark Cave-Ayland
 *
 * 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 "qemu/osdep.h"
#include "hw/pci/pci_device.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
#include "hw/net/mii.h"
#include "net/net.h"
#include "qemu/module.h"
#include "net/checksum.h"
#include "net/eth.h"
#include "system/system.h"
#include "trace.h"
#include "qom/object.h"

#define HME_REG_SIZE                   0x8000

#define HME_SEB_REG_SIZE               0x2000

#define HME_SEBI_RESET                 0x0
#define HME_SEB_RESET_ETX              0x1
#define HME_SEB_RESET_ERX              0x2

#define HME_SEBI_STAT                  0x100
#define HME_SEBI_STAT_LINUXBUG         0x108
#define HME_SEB_STAT_RXTOHOST          0x10000
#define HME_SEB_STAT_NORXD             0x20000
#define HME_SEB_STAT_MIFIRQ            0x800000
#define HME_SEB_STAT_HOSTTOTX          0x1000000
#define HME_SEB_STAT_TXALL             0x2000000

#define HME_SEBI_IMASK                 0x104
#define HME_SEBI_IMASK_LINUXBUG        0x10c

#define HME_ETX_REG_SIZE               0x2000

#define HME_ETXI_PENDING               0x0

#define HME_ETXI_RING                  0x8
#define HME_ETXI_RING_ADDR             0xffffff00
#define HME_ETXI_RING_OFFSET           0xff

#define HME_ETXI_RSIZE                 0x2c

#define HME_ERX_REG_SIZE               0x2000

#define HME_ERXI_CFG                   0x0
#define HME_ERX_CFG_RINGSIZE           0x600
#define HME_ERX_CFG_RINGSIZE_SHIFT     9
#define HME_ERX_CFG_BYTEOFFSET         0x38
#define HME_ERX_CFG_BYTEOFFSET_SHIFT   3
#define HME_ERX_CFG_CSUMSTART          0x7f0000
#define HME_ERX_CFG_CSUMSHIFT          16

#define HME_ERXI_RING                  0x4
#define HME_ERXI_RING_ADDR             0xffffff00
#define HME_ERXI_RING_OFFSET           0xff

#define HME_MAC_REG_SIZE               0x1000

#define HME_MACI_TXCFG                 0x20c
#define HME_MAC_TXCFG_ENABLE           0x1

#define HME_MACI_RXCFG                 0x30c
#define HME_MAC_RXCFG_ENABLE           0x1
#define HME_MAC_RXCFG_PMISC            0x40
#define HME_MAC_RXCFG_HENABLE          0x800

#define HME_MACI_MACADDR2              0x318
#define HME_MACI_MACADDR1              0x31c
#define HME_MACI_MACADDR0              0x320

#define HME_MACI_HASHTAB3              0x340
#define HME_MACI_HASHTAB2              0x344
#define HME_MACI_HASHTAB1              0x348
#define HME_MACI_HASHTAB0              0x34c

#define HME_MIF_REG_SIZE               0x20

#define HME_MIFI_FO                    0xc
#define HME_MIF_FO_ST                  0xc0000000
#define HME_MIF_FO_ST_SHIFT            30
#define HME_MIF_FO_OPC                 0x30000000
#define HME_MIF_FO_OPC_SHIFT           28
#define HME_MIF_FO_PHYAD               0x0f800000
#define HME_MIF_FO_PHYAD_SHIFT         23
#define HME_MIF_FO_REGAD               0x007c0000
#define HME_MIF_FO_REGAD_SHIFT         18
#define HME_MIF_FO_TAMSB               0x20000
#define HME_MIF_FO_TALSB               0x10000
#define HME_MIF_FO_DATA                0xffff

#define HME_MIFI_CFG                   0x10
#define HME_MIF_CFG_MDI0               0x100
#define HME_MIF_CFG_MDI1               0x200

#define HME_MIFI_IMASK                 0x14

#define HME_MIFI_STAT                  0x18


/* Wired HME PHY addresses */
#define HME_PHYAD_INTERNAL     1
#define HME_PHYAD_EXTERNAL     0

#define MII_COMMAND_START      0x1
#define MII_COMMAND_READ       0x2
#define MII_COMMAND_WRITE      0x1

#define TYPE_SUNHME "sunhme"
OBJECT_DECLARE_SIMPLE_TYPE(SunHMEState, SUNHME)

/* Maximum size of buffer */
#define HME_FIFO_SIZE          0x800

/* Size of TX/RX descriptor */
#define HME_DESC_SIZE          0x8

#define HME_XD_OWN             0x80000000
#define HME_XD_OFL             0x40000000
#define HME_XD_SOP             0x40000000
#define HME_XD_EOP             0x20000000
#define HME_XD_RXLENMSK        0x3fff0000
#define HME_XD_RXLENSHIFT      16
#define HME_XD_RXCKSUM         0xffff
#define HME_XD_TXLENMSK        0x00001fff
#define HME_XD_TXCKSUM         0x10000000
#define HME_XD_TXCSSTUFF       0xff00000
#define HME_XD_TXCSSTUFFSHIFT  20
#define HME_XD_TXCSSTART       0xfc000
#define HME_XD_TXCSSTARTSHIFT  14

#define HME_MII_REGS_SIZE      0x20

struct SunHMEState {
    /*< private >*/
    PCIDevice parent_obj;

    NICState *nic;
    NICConf conf;

    MemoryRegion hme;
    MemoryRegion sebreg;
    MemoryRegion etxreg;
    MemoryRegion erxreg;
    MemoryRegion macreg;
    MemoryRegion mifreg;

    uint32_t sebregs[HME_SEB_REG_SIZE >> 2];
    uint32_t etxregs[HME_ETX_REG_SIZE >> 2];
    uint32_t erxregs[HME_ERX_REG_SIZE >> 2];
    uint32_t macregs[HME_MAC_REG_SIZE >> 2];
    uint32_t mifregs[HME_MIF_REG_SIZE >> 2];

    uint16_t miiregs[HME_MII_REGS_SIZE];
};

static const Property sunhme_properties[] = {
    DEFINE_NIC_PROPERTIES(SunHMEState, conf),
};

static void sunhme_reset_tx(SunHMEState *s)
{
    /* Indicate TX reset complete */
    s->sebregs[HME_SEBI_RESET] &= ~HME_SEB_RESET_ETX;
}

static void sunhme_reset_rx(SunHMEState *s)
{
    /* Indicate RX reset complete */
    s->sebregs[HME_SEBI_RESET] &= ~HME_SEB_RESET_ERX;
}

static void sunhme_update_irq(SunHMEState *s)
{
    PCIDevice *d = PCI_DEVICE(s);
    int level;

    /* MIF interrupt mask (16-bit) */
    uint32_t mifmask = ~(s->mifregs[HME_MIFI_IMASK >> 2]) & 0xffff;
    uint32_t mif = s->mifregs[HME_MIFI_STAT >> 2] & mifmask;

    /* Main SEB interrupt mask (include MIF status from above) */
    uint32_t sebmask = ~(s->sebregs[HME_SEBI_IMASK >> 2]) &
                       ~HME_SEB_STAT_MIFIRQ;
    uint32_t seb = s->sebregs[HME_SEBI_STAT >> 2] & sebmask;
    if (mif) {
        seb |= HME_SEB_STAT_MIFIRQ;
    }

    level = (seb ? 1 : 0);
    trace_sunhme_update_irq(mifmask, mif, sebmask, seb, level);

    pci_set_irq(d, level);
}

static void sunhme_seb_write(void *opaque, hwaddr addr,
                          uint64_t val, unsigned size)
{
    SunHMEState *s = SUNHME(opaque);

    trace_sunhme_seb_write(addr, val);

    /* Handly buggy Linux drivers before 4.13 which have
       the wrong offsets for HME_SEBI_STAT and HME_SEBI_IMASK */
    switch (addr) {
    case HME_SEBI_STAT_LINUXBUG:
        addr = HME_SEBI_STAT;
        break;
    case HME_SEBI_IMASK_LINUXBUG:
        addr = HME_SEBI_IMASK;
        break;
    default:
        break;
    }

    switch (addr) {
    case HME_SEBI_RESET:
        if (val & HME_SEB_RESET_ETX) {
            sunhme_reset_tx(s);
        }
        if (val & HME_SEB_RESET_ERX) {
            sunhme_reset_rx(s);
        }
        val = s->sebregs[HME_SEBI_RESET >> 2];
        break;
    }

    s->sebregs[addr >> 2] = val;
}

static uint64_t sunhme_seb_read(void *opaque, hwaddr addr,
                             unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t val;

    /* Handly buggy Linux drivers before 4.13 which have
       the wrong offsets for HME_SEBI_STAT and HME_SEBI_IMASK */
    switch (addr) {
    case HME_SEBI_STAT_LINUXBUG:
        addr = HME_SEBI_STAT;
        break;
    case HME_SEBI_IMASK_LINUXBUG:
        addr = HME_SEBI_IMASK;
        break;
    default:
        break;
    }

    val = s->sebregs[addr >> 2];

    switch (addr) {
    case HME_SEBI_STAT:
        /* Autoclear status (except MIF) */
        s->sebregs[HME_SEBI_STAT >> 2] &= HME_SEB_STAT_MIFIRQ;
        sunhme_update_irq(s);
        break;
    }

    trace_sunhme_seb_read(addr, val);

    return val;
}

static const MemoryRegionOps sunhme_seb_ops = {
    .read = sunhme_seb_read,
    .write = sunhme_seb_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void sunhme_transmit(SunHMEState *s);

static void sunhme_etx_write(void *opaque, hwaddr addr,
                          uint64_t val, unsigned size)
{
    SunHMEState *s = SUNHME(opaque);

    trace_sunhme_etx_write(addr, val);

    switch (addr) {
    case HME_ETXI_PENDING:
        if (val) {
            sunhme_transmit(s);
        }
        break;
    }

    s->etxregs[addr >> 2] = val;
}

static uint64_t sunhme_etx_read(void *opaque, hwaddr addr,
                             unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t val;

    val = s->etxregs[addr >> 2];

    trace_sunhme_etx_read(addr, val);

    return val;
}

static const MemoryRegionOps sunhme_etx_ops = {
    .read = sunhme_etx_read,
    .write = sunhme_etx_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void sunhme_erx_write(void *opaque, hwaddr addr,
                          uint64_t val, unsigned size)
{
    SunHMEState *s = SUNHME(opaque);

    trace_sunhme_erx_write(addr, val);

    s->erxregs[addr >> 2] = val;
}

static uint64_t sunhme_erx_read(void *opaque, hwaddr addr,
                             unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t val;

    val = s->erxregs[addr >> 2];

    trace_sunhme_erx_read(addr, val);

    return val;
}

static const MemoryRegionOps sunhme_erx_ops = {
    .read = sunhme_erx_read,
    .write = sunhme_erx_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void sunhme_mac_write(void *opaque, hwaddr addr,
                          uint64_t val, unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t oldval = s->macregs[addr >> 2];

    trace_sunhme_mac_write(addr, val);

    s->macregs[addr >> 2] = val;

    switch (addr) {
    case HME_MACI_RXCFG:
        if (!(oldval & HME_MAC_RXCFG_ENABLE) &&
             (val & HME_MAC_RXCFG_ENABLE)) {
            qemu_flush_queued_packets(qemu_get_queue(s->nic));
        }
        break;
    }
}

static uint64_t sunhme_mac_read(void *opaque, hwaddr addr,
                             unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t val;

    val = s->macregs[addr >> 2];

    trace_sunhme_mac_read(addr, val);

    return val;
}

static const MemoryRegionOps sunhme_mac_ops = {
    .read = sunhme_mac_read,
    .write = sunhme_mac_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void sunhme_mii_write(SunHMEState *s, uint8_t reg, uint16_t data)
{
    trace_sunhme_mii_write(reg, data);

    switch (reg) {
    case MII_BMCR:
        if (data & MII_BMCR_RESET) {
            /* Autoclear reset bit, enable auto negotiation */
            data &= ~MII_BMCR_RESET;
            data |= MII_BMCR_AUTOEN;
        }
        if (data & MII_BMCR_ANRESTART) {
            /* Autoclear auto negotiation restart */
            data &= ~MII_BMCR_ANRESTART;

            /* Indicate negotiation complete */
            s->miiregs[MII_BMSR] |= MII_BMSR_AN_COMP;

            if (!qemu_get_queue(s->nic)->link_down) {
                s->miiregs[MII_ANLPAR] |= MII_ANLPAR_TXFD;
                s->miiregs[MII_BMSR] |= MII_BMSR_LINK_ST;
            }
        }
        break;
    }

    s->miiregs[reg] = data;
}

static uint16_t sunhme_mii_read(SunHMEState *s, uint8_t reg)
{
    uint16_t data = s->miiregs[reg];

    trace_sunhme_mii_read(reg, data);

    return data;
}

static void sunhme_mif_write(void *opaque, hwaddr addr,
                          uint64_t val, unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint8_t cmd, reg;
    uint16_t data;

    trace_sunhme_mif_write(addr, val);

    switch (addr) {
    case HME_MIFI_CFG:
        /* Mask the read-only bits */
        val &= ~(HME_MIF_CFG_MDI0 | HME_MIF_CFG_MDI1);
        val |= s->mifregs[HME_MIFI_CFG >> 2] &
               (HME_MIF_CFG_MDI0 | HME_MIF_CFG_MDI1);
        break;
    case HME_MIFI_FO:
        /* Detect start of MII command */
        if ((val & HME_MIF_FO_ST) >> HME_MIF_FO_ST_SHIFT
                != MII_COMMAND_START) {
            val |= HME_MIF_FO_TALSB;
            break;
        }

        /* Internal phy only */
        if ((val & HME_MIF_FO_PHYAD) >> HME_MIF_FO_PHYAD_SHIFT
                != HME_PHYAD_INTERNAL) {
            val |= HME_MIF_FO_TALSB;
            break;
        }

        cmd = (val & HME_MIF_FO_OPC) >> HME_MIF_FO_OPC_SHIFT;
        reg = (val & HME_MIF_FO_REGAD) >> HME_MIF_FO_REGAD_SHIFT;
        data = (val & HME_MIF_FO_DATA);

        switch (cmd) {
        case MII_COMMAND_WRITE:
            sunhme_mii_write(s, reg, data);
            break;

        case MII_COMMAND_READ:
            val &= ~HME_MIF_FO_DATA;
            val |= sunhme_mii_read(s, reg);
            break;
        }

        val |= HME_MIF_FO_TALSB;
        break;
    }

    s->mifregs[addr >> 2] = val;
}

static uint64_t sunhme_mif_read(void *opaque, hwaddr addr,
                             unsigned size)
{
    SunHMEState *s = SUNHME(opaque);
    uint64_t val;

    val = s->mifregs[addr >> 2];

    switch (addr) {
    case HME_MIFI_STAT:
        /* Autoclear MIF interrupt status */
        s->mifregs[HME_MIFI_STAT >> 2] = 0;
        sunhme_update_irq(s);
        break;
    }

    trace_sunhme_mif_read(addr, val);

    return val;
}

static const MemoryRegionOps sunhme_mif_ops = {
    .read = sunhme_mif_read,
    .write = sunhme_mif_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void sunhme_transmit_frame(SunHMEState *s, uint8_t *buf, int size)
{
    qemu_send_packet(qemu_get_queue(s->nic), buf, size);
}

static inline int sunhme_get_tx_ring_count(SunHMEState *s)
{
    return (s->etxregs[HME_ETXI_RSIZE >> 2] + 1) << 4;
}

static inline int sunhme_get_tx_ring_nr(SunHMEState *s)
{
    return s->etxregs[HME_ETXI_RING >> 2] & HME_ETXI_RING_OFFSET;
}

static inline void sunhme_set_tx_ring_nr(SunHMEState *s, int i)
{
    uint32_t ring = s->etxregs[HME_ETXI_RING >> 2] & ~HME_ETXI_RING_OFFSET;
    ring |= i & HME_ETXI_RING_OFFSET;

    s->etxregs[HME_ETXI_RING >> 2] = ring;
}

static void sunhme_transmit(SunHMEState *s)
{
    PCIDevice *d = PCI_DEVICE(s);
    dma_addr_t tb, addr;
    uint32_t intstatus, status, buffer, sum = 0;
    int cr, nr, len, xmit_pos, csum_offset = 0, csum_stuff_offset = 0;
    uint16_t csum = 0;
    uint8_t xmit_buffer[HME_FIFO_SIZE];

    tb = s->etxregs[HME_ETXI_RING >> 2] & HME_ETXI_RING_ADDR;
    nr = sunhme_get_tx_ring_count(s);
    cr = sunhme_get_tx_ring_nr(s);

    pci_dma_read(d, tb + cr * HME_DESC_SIZE, &status, 4);
    pci_dma_read(d, tb + cr * HME_DESC_SIZE + 4, &buffer, 4);

    xmit_pos = 0;
    while (status & HME_XD_OWN) {
        trace_sunhme_tx_desc(buffer, status, cr, nr);

        /* Copy data into transmit buffer */
        addr = buffer;
        len = status & HME_XD_TXLENMSK;

        if (xmit_pos + len > HME_FIFO_SIZE) {
            len = HME_FIFO_SIZE - xmit_pos;
        }

        pci_dma_read(d, addr, &xmit_buffer[xmit_pos], len);
        xmit_pos += len;

        /* Detect start of packet for TX checksum */
        if (status & HME_XD_SOP) {
            sum = 0;
            csum_offset = (status & HME_XD_TXCSSTART) >> HME_XD_TXCSSTARTSHIFT;
            csum_stuff_offset = (status & HME_XD_TXCSSTUFF) >>
                                HME_XD_TXCSSTUFFSHIFT;
        }

        if (status & HME_XD_TXCKSUM) {
            /* Only start calculation from csum_offset */
            if (xmit_pos - len <= csum_offset && xmit_pos > csum_offset) {
                sum += net_checksum_add(xmit_pos - csum_offset,
                                        xmit_buffer + csum_offset);
                trace_sunhme_tx_xsum_add(csum_offset, xmit_pos - csum_offset);
            } else {
                sum += net_checksum_add(len, xmit_buffer + xmit_pos - len);
                trace_sunhme_tx_xsum_add(xmit_pos - len, len);
            }
        }

        /* Detect end of packet for TX checksum */
        if (status & HME_XD_EOP) {
            /* Stuff the checksum if required */
            if (status & HME_XD_TXCKSUM) {
                csum = net_checksum_finish(sum);
                stw_be_p(xmit_buffer + csum_stuff_offset, csum);
                trace_sunhme_tx_xsum_stuff(csum, csum_stuff_offset);
            }

            if (s->macregs[HME_MACI_TXCFG >> 2] & HME_MAC_TXCFG_ENABLE) {
                sunhme_transmit_frame(s, xmit_buffer, xmit_pos);
                trace_sunhme_tx_done(xmit_pos);
            }
        }

        /* Update status */
        status &= ~HME_XD_OWN;
        pci_dma_write(d, tb + cr * HME_DESC_SIZE, &status, 4);

        /* Move onto next descriptor */
        cr++;
        if (cr >= nr) {
            cr = 0;
        }
        sunhme_set_tx_ring_nr(s, cr);

        pci_dma_read(d, tb + cr * HME_DESC_SIZE, &status, 4);
        pci_dma_read(d, tb + cr * HME_DESC_SIZE + 4, &buffer, 4);

        /* Indicate TX complete */
        intstatus = s->sebregs[HME_SEBI_STAT >> 2];
        intstatus |= HME_SEB_STAT_HOSTTOTX;
        s->sebregs[HME_SEBI_STAT >> 2] = intstatus;

        /* Autoclear TX pending */
        s->etxregs[HME_ETXI_PENDING >> 2] = 0;

        sunhme_update_irq(s);
    }

    /* TX FIFO now clear */
    intstatus = s->sebregs[HME_SEBI_STAT >> 2];
    intstatus |= HME_SEB_STAT_TXALL;
    s->sebregs[HME_SEBI_STAT >> 2] = intstatus;
    sunhme_update_irq(s);
}

static bool sunhme_can_receive(NetClientState *nc)
{
    SunHMEState *s = qemu_get_nic_opaque(nc);

    return !!(s->macregs[HME_MACI_RXCFG >> 2] & HME_MAC_RXCFG_ENABLE);
}

static void sunhme_link_status_changed(NetClientState *nc)
{
    SunHMEState *s = qemu_get_nic_opaque(nc);

    if (nc->link_down) {
        s->miiregs[MII_ANLPAR] &= ~MII_ANLPAR_TXFD;
        s->miiregs[MII_BMSR] &= ~MII_BMSR_LINK_ST;
    } else {
        s->miiregs[MII_ANLPAR] |= MII_ANLPAR_TXFD;
        s->miiregs[MII_BMSR] |= MII_BMSR_LINK_ST;
    }

    /* Exact bits unknown */
    s->mifregs[HME_MIFI_STAT >> 2] = 0xffff;
    sunhme_update_irq(s);
}

static inline int sunhme_get_rx_ring_count(SunHMEState *s)
{
    uint32_t rings = (s->erxregs[HME_ERXI_CFG >> 2] & HME_ERX_CFG_RINGSIZE)
                      >> HME_ERX_CFG_RINGSIZE_SHIFT;

    switch (rings) {
    case 0:
        return 32;
    case 1:
        return 64;
    case 2:
        return 128;
    case 3:
        return 256;
    }

    return 0;
}

static inline int sunhme_get_rx_ring_nr(SunHMEState *s)
{
    return s->erxregs[HME_ERXI_RING >> 2] & HME_ERXI_RING_OFFSET;
}

static inline void sunhme_set_rx_ring_nr(SunHMEState *s, int i)
{
    uint32_t ring = s->erxregs[HME_ERXI_RING >> 2] & ~HME_ERXI_RING_OFFSET;
    ring |= i & HME_ERXI_RING_OFFSET;

    s->erxregs[HME_ERXI_RING >> 2] = ring;
}

static ssize_t sunhme_receive(NetClientState *nc, const uint8_t *buf,
                              size_t size)
{
    SunHMEState *s = qemu_get_nic_opaque(nc);
    PCIDevice *d = PCI_DEVICE(s);
    dma_addr_t rb, addr;
    uint32_t intstatus, status, buffer, buffersize, sum;
    uint16_t csum;
    int nr, cr, len, rxoffset, csum_offset;

    trace_sunhme_rx_incoming(size);

    /* Do nothing if MAC RX disabled */
    if (!(s->macregs[HME_MACI_RXCFG >> 2] & HME_MAC_RXCFG_ENABLE)) {
        return 0;
    }

    trace_sunhme_rx_filter_destmac(buf[0], buf[1], buf[2],
                                   buf[3], buf[4], buf[5]);

    /* Check destination MAC address */
    if (!(s->macregs[HME_MACI_RXCFG >> 2] & HME_MAC_RXCFG_PMISC)) {
        /* Try and match local MAC address */
        if (((s->macregs[HME_MACI_MACADDR0 >> 2] & 0xff00) >> 8) == buf[0] &&
             (s->macregs[HME_MACI_MACADDR0 >> 2] & 0xff) == buf[1] &&
            ((s->macregs[HME_MACI_MACADDR1 >> 2] & 0xff00) >> 8) == buf[2] &&
             (s->macregs[HME_MACI_MACADDR1 >> 2] & 0xff) == buf[3] &&
            ((s->macregs[HME_MACI_MACADDR2 >> 2] & 0xff00) >> 8) == buf[4] &&
             (s->macregs[HME_MACI_MACADDR2 >> 2] & 0xff) == buf[5]) {
            /* Matched local MAC address */
            trace_sunhme_rx_filter_local_match();
        } else if (buf[0] == 0xff && buf[1] == 0xff && buf[2] == 0xff &&
                   buf[3] == 0xff && buf[4] == 0xff && buf[5] == 0xff) {
            /* Matched broadcast address */
            trace_sunhme_rx_filter_bcast_match();
        } else if (s->macregs[HME_MACI_RXCFG >> 2] & HME_MAC_RXCFG_HENABLE) {
            /* Didn't match local address, check hash filter */
            int mcast_idx = net_crc32_le(buf, ETH_ALEN) >> 26;
            if (!(s->macregs[(HME_MACI_HASHTAB0 >> 2) - (mcast_idx >> 4)] &
                    (1 << (mcast_idx & 0xf)))) {
                /* Didn't match hash filter */
                trace_sunhme_rx_filter_hash_nomatch();
                trace_sunhme_rx_filter_reject();
                return -1;
            } else {
                trace_sunhme_rx_filter_hash_match();
            }
        } else {
            /* Not for us */
            trace_sunhme_rx_filter_reject();
            return -1;
        }
    } else {
        trace_sunhme_rx_filter_promisc_match();
    }

    trace_sunhme_rx_filter_accept();

    rb = s->erxregs[HME_ERXI_RING >> 2] & HME_ERXI_RING_ADDR;
    nr = sunhme_get_rx_ring_count(s);
    cr = sunhme_get_rx_ring_nr(s);

    pci_dma_read(d, rb + cr * HME_DESC_SIZE, &status, 4);
    pci_dma_read(d, rb + cr * HME_DESC_SIZE + 4, &buffer, 4);

    /* If we don't own the current descriptor then indicate overflow error */
    if (!(status & HME_XD_OWN)) {
        s->sebregs[HME_SEBI_STAT >> 2] |= HME_SEB_STAT_NORXD;
        sunhme_update_irq(s);
        trace_sunhme_rx_norxd();
        return -1;
    }

    rxoffset = (s->erxregs[HME_ERXI_CFG >> 2] & HME_ERX_CFG_BYTEOFFSET) >>
                HME_ERX_CFG_BYTEOFFSET_SHIFT;

    addr = buffer + rxoffset;
    buffersize = (status & HME_XD_RXLENMSK) >> HME_XD_RXLENSHIFT;

    /* Detect receive overflow */
    len = size;
    if (size > buffersize) {
        status |= HME_XD_OFL;
        len = buffersize;
    }

    pci_dma_write(d, addr, buf, len);

    trace_sunhme_rx_desc(buffer, rxoffset, status, len, cr, nr);

    /* Calculate the receive checksum */
    csum_offset = (s->erxregs[HME_ERXI_CFG >> 2] & HME_ERX_CFG_CSUMSTART) >>
                  HME_ERX_CFG_CSUMSHIFT << 1;
    sum = 0;
    sum += net_checksum_add(len - csum_offset, (uint8_t *)buf + csum_offset);
    csum = net_checksum_finish(sum);

    trace_sunhme_rx_xsum_calc(csum);

    /* Update status */
    status &= ~HME_XD_OWN;
    status &= ~HME_XD_RXLENMSK;
    status |= len << HME_XD_RXLENSHIFT;
    status &= ~HME_XD_RXCKSUM;
    status |= csum;

    pci_dma_write(d, rb + cr * HME_DESC_SIZE, &status, 4);

    cr++;
    if (cr >= nr) {
        cr = 0;
    }

    sunhme_set_rx_ring_nr(s, cr);

    /* Indicate RX complete */
    intstatus = s->sebregs[HME_SEBI_STAT >> 2];
    intstatus |= HME_SEB_STAT_RXTOHOST;
    s->sebregs[HME_SEBI_STAT >> 2] = intstatus;

    sunhme_update_irq(s);

    return len;
}

static NetClientInfo net_sunhme_info = {
    .type = NET_CLIENT_DRIVER_NIC,
    .size = sizeof(NICState),
    .can_receive = sunhme_can_receive,
    .receive = sunhme_receive,
    .link_status_changed = sunhme_link_status_changed,
};

static void sunhme_realize(PCIDevice *pci_dev, Error **errp)
{
    SunHMEState *s = SUNHME(pci_dev);
    DeviceState *d = DEVICE(pci_dev);
    uint8_t *pci_conf;

    pci_conf = pci_dev->config;
    pci_conf[PCI_INTERRUPT_PIN] = 1;    /* interrupt pin A */

    memory_region_init(&s->hme, OBJECT(pci_dev), "sunhme", HME_REG_SIZE);
    pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->hme);

    memory_region_init_io(&s->sebreg, OBJECT(pci_dev), &sunhme_seb_ops, s,
                          "sunhme.seb", HME_SEB_REG_SIZE);
    memory_region_add_subregion(&s->hme, 0, &s->sebreg);

    memory_region_init_io(&s->etxreg, OBJECT(pci_dev), &sunhme_etx_ops, s,
                          "sunhme.etx", HME_ETX_REG_SIZE);
    memory_region_add_subregion(&s->hme, 0x2000, &s->etxreg);

    memory_region_init_io(&s->erxreg, OBJECT(pci_dev), &sunhme_erx_ops, s,
                          "sunhme.erx", HME_ERX_REG_SIZE);
    memory_region_add_subregion(&s->hme, 0x4000, &s->erxreg);

    memory_region_init_io(&s->macreg, OBJECT(pci_dev), &sunhme_mac_ops, s,
                          "sunhme.mac", HME_MAC_REG_SIZE);
    memory_region_add_subregion(&s->hme, 0x6000, &s->macreg);

    memory_region_init_io(&s->mifreg, OBJECT(pci_dev), &sunhme_mif_ops, s,
                          "sunhme.mif", HME_MIF_REG_SIZE);
    memory_region_add_subregion(&s->hme, 0x7000, &s->mifreg);

    qemu_macaddr_default_if_unset(&s->conf.macaddr);
    s->nic = qemu_new_nic(&net_sunhme_info, &s->conf,
                          object_get_typename(OBJECT(d)), d->id,
                          &d->mem_reentrancy_guard, s);
    qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
}

static void sunhme_instance_init(Object *obj)
{
    SunHMEState *s = SUNHME(obj);

    device_add_bootindex_property(obj, &s->conf.bootindex,
                                  "bootindex", "/ethernet-phy@0",
                                  DEVICE(obj));
}

static void sunhme_reset(DeviceState *ds)
{
    SunHMEState *s = SUNHME(ds);

    /* Configure internal transceiver */
    s->mifregs[HME_MIFI_CFG >> 2] |= HME_MIF_CFG_MDI0;

    /* Advertise auto, 100Mbps FD */
    s->miiregs[MII_ANAR] = MII_ANAR_TXFD;
    s->miiregs[MII_BMSR] = MII_BMSR_AUTONEG | MII_BMSR_100TX_FD |
                           MII_BMSR_AN_COMP;

    if (!qemu_get_queue(s->nic)->link_down) {
        s->miiregs[MII_ANLPAR] |= MII_ANLPAR_TXFD;
        s->miiregs[MII_BMSR] |= MII_BMSR_LINK_ST;
    }

    /* Set manufacturer */
    s->miiregs[MII_PHYID1] = DP83840_PHYID1;
    s->miiregs[MII_PHYID2] = DP83840_PHYID2;

    /* Configure default interrupt mask */
    s->mifregs[HME_MIFI_IMASK >> 2] = 0xffff;
    s->sebregs[HME_SEBI_IMASK >> 2] = 0xff7fffff;
}

static const VMStateDescription vmstate_hme = {
    .name = "sunhme",
    .version_id = 0,
    .minimum_version_id = 0,
    .fields = (const VMStateField[]) {
        VMSTATE_PCI_DEVICE(parent_obj, SunHMEState),
        VMSTATE_MACADDR(conf.macaddr, SunHMEState),
        VMSTATE_UINT32_ARRAY(sebregs, SunHMEState, (HME_SEB_REG_SIZE >> 2)),
        VMSTATE_UINT32_ARRAY(etxregs, SunHMEState, (HME_ETX_REG_SIZE >> 2)),
        VMSTATE_UINT32_ARRAY(erxregs, SunHMEState, (HME_ERX_REG_SIZE >> 2)),
        VMSTATE_UINT32_ARRAY(macregs, SunHMEState, (HME_MAC_REG_SIZE >> 2)),
        VMSTATE_UINT32_ARRAY(mifregs, SunHMEState, (HME_MIF_REG_SIZE >> 2)),
        VMSTATE_UINT16_ARRAY(miiregs, SunHMEState, HME_MII_REGS_SIZE),
        VMSTATE_END_OF_LIST()
    }
};

static void sunhme_class_init(ObjectClass *klass, const void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);

    k->realize = sunhme_realize;
    k->vendor_id = PCI_VENDOR_ID_SUN;
    k->device_id = PCI_DEVICE_ID_SUN_HME;
    k->class_id = PCI_CLASS_NETWORK_ETHERNET;
    dc->vmsd = &vmstate_hme;
    device_class_set_legacy_reset(dc, sunhme_reset);
    device_class_set_props(dc, sunhme_properties);
    set_bit(DEVICE_CATEGORY_NETWORK, dc->categories);
}

static const TypeInfo sunhme_info = {
    .name          = TYPE_SUNHME,
    .parent        = TYPE_PCI_DEVICE,
    .class_init    = sunhme_class_init,
    .instance_size = sizeof(SunHMEState),
    .instance_init = sunhme_instance_init,
    .interfaces = (const InterfaceInfo[]) {
        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
        { }
    }
};

static void sunhme_register_types(void)
{
    type_register_static(&sunhme_info);
}

type_init(sunhme_register_types)