hw/net/xgmac.c - qemu - Git at Google

 /*
  * QEMU model of XGMAC Ethernet.
  *
  * derived from the Xilinx AXI-Ethernet by Edgar E. Iglesias.
  *
  * Copyright (c) 2011 Calxeda, Inc.
  *
  * 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/irq.h"
 #include "hw/qdev-properties.h"
 #include "hw/sysbus.h"
 #include "migration/vmstate.h"
 #include "qemu/module.h"
 #include "net/net.h"
 #include "qom/object.h"

 #ifdef DEBUG_XGMAC
 #define DEBUGF_BRK(message, args...) do { \
                                          fprintf(stderr, (message), ## args); \
                                      } while (0)
 #else
 #define DEBUGF_BRK(message, args...) do { } while (0)
 #endif

 #define XGMAC_CONTROL           0x00000000   /* MAC Configuration */
 #define XGMAC_FRAME_FILTER      0x00000001   /* MAC Frame Filter */
 #define XGMAC_FLOW_CTRL         0x00000006   /* MAC Flow Control */
 #define XGMAC_VLAN_TAG          0x00000007   /* VLAN Tags */
 #define XGMAC_VERSION           0x00000008   /* Version */
 /* VLAN tag for insertion or replacement into tx frames */
 #define XGMAC_VLAN_INCL         0x00000009
 #define XGMAC_LPI_CTRL          0x0000000a   /* LPI Control and Status */
 #define XGMAC_LPI_TIMER         0x0000000b   /* LPI Timers Control */
 #define XGMAC_TX_PACE           0x0000000c   /* Transmit Pace and Stretch */
 #define XGMAC_VLAN_HASH         0x0000000d   /* VLAN Hash Table */
 #define XGMAC_DEBUG             0x0000000e   /* Debug */
 #define XGMAC_INT_STATUS        0x0000000f   /* Interrupt and Control */
 /* HASH table registers */
 #define XGMAC_HASH(n)           ((0x00000300/4) + (n))
 #define XGMAC_NUM_HASH          16
 /* Operation Mode */
 #define XGMAC_OPMODE            (0x00000400/4)
 /* Remote Wake-Up Frame Filter */
 #define XGMAC_REMOTE_WAKE       (0x00000700/4)
 /* PMT Control and Status */
 #define XGMAC_PMT               (0x00000704/4)

 #define XGMAC_ADDR_HIGH(reg)    (0x00000010+((reg) * 2))
 #define XGMAC_ADDR_LOW(reg)     (0x00000011+((reg) * 2))

 #define DMA_BUS_MODE            0x000003c0   /* Bus Mode */
 #define DMA_XMT_POLL_DEMAND     0x000003c1   /* Transmit Poll Demand */
 #define DMA_RCV_POLL_DEMAND     0x000003c2   /* Received Poll Demand */
 #define DMA_RCV_BASE_ADDR       0x000003c3   /* Receive List Base */
 #define DMA_TX_BASE_ADDR        0x000003c4   /* Transmit List Base */
 #define DMA_STATUS              0x000003c5   /* Status Register */
 #define DMA_CONTROL             0x000003c6   /* Ctrl (Operational Mode) */
 #define DMA_INTR_ENA            0x000003c7   /* Interrupt Enable */
 #define DMA_MISSED_FRAME_CTR    0x000003c8   /* Missed Frame Counter */
 /* Receive Interrupt Watchdog Timer */
 #define DMA_RI_WATCHDOG_TIMER   0x000003c9
 #define DMA_AXI_BUS             0x000003ca   /* AXI Bus Mode */
 #define DMA_AXI_STATUS          0x000003cb   /* AXI Status */
 #define DMA_CUR_TX_DESC_ADDR    0x000003d2   /* Current Host Tx Descriptor */
 #define DMA_CUR_RX_DESC_ADDR    0x000003d3   /* Current Host Rx Descriptor */
 #define DMA_CUR_TX_BUF_ADDR     0x000003d4   /* Current Host Tx Buffer */
 #define DMA_CUR_RX_BUF_ADDR     0x000003d5   /* Current Host Rx Buffer */
 #define DMA_HW_FEATURE          0x000003d6   /* Enabled Hardware Features */

 /* DMA Status register defines */
 #define DMA_STATUS_GMI          0x08000000   /* MMC interrupt */
 #define DMA_STATUS_GLI          0x04000000   /* GMAC Line interface int */
 #define DMA_STATUS_EB_MASK      0x00380000   /* Error Bits Mask */
 #define DMA_STATUS_EB_TX_ABORT  0x00080000   /* Error Bits - TX Abort */
 #define DMA_STATUS_EB_RX_ABORT  0x00100000   /* Error Bits - RX Abort */
 #define DMA_STATUS_TS_MASK      0x00700000   /* Transmit Process State */
 #define DMA_STATUS_TS_SHIFT     20
 #define DMA_STATUS_RS_MASK      0x000e0000   /* Receive Process State */
 #define DMA_STATUS_RS_SHIFT     17
 #define DMA_STATUS_NIS          0x00010000   /* Normal Interrupt Summary */
 #define DMA_STATUS_AIS          0x00008000   /* Abnormal Interrupt Summary */
 #define DMA_STATUS_ERI          0x00004000   /* Early Receive Interrupt */
 #define DMA_STATUS_FBI          0x00002000   /* Fatal Bus Error Interrupt */
 #define DMA_STATUS_ETI          0x00000400   /* Early Transmit Interrupt */
 #define DMA_STATUS_RWT          0x00000200   /* Receive Watchdog Timeout */
 #define DMA_STATUS_RPS          0x00000100   /* Receive Process Stopped */
 #define DMA_STATUS_RU           0x00000080   /* Receive Buffer Unavailable */
 #define DMA_STATUS_RI           0x00000040   /* Receive Interrupt */
 #define DMA_STATUS_UNF          0x00000020   /* Transmit Underflow */
 #define DMA_STATUS_OVF          0x00000010   /* Receive Overflow */
 #define DMA_STATUS_TJT          0x00000008   /* Transmit Jabber Timeout */
 #define DMA_STATUS_TU           0x00000004   /* Transmit Buffer Unavailable */
 #define DMA_STATUS_TPS          0x00000002   /* Transmit Process Stopped */
 #define DMA_STATUS_TI           0x00000001   /* Transmit Interrupt */

 /* DMA Control register defines */
 #define DMA_CONTROL_ST          0x00002000   /* Start/Stop Transmission */
 #define DMA_CONTROL_SR          0x00000002   /* Start/Stop Receive */
 #define DMA_CONTROL_DFF         0x01000000   /* Disable flush of rx frames */

 struct desc {
     uint32_t ctl_stat;
     uint16_t buffer1_size;
     uint16_t buffer2_size;
     uint32_t buffer1_addr;
     uint32_t buffer2_addr;
     uint32_t ext_stat;
     uint32_t res[3];
 };

 #define R_MAX 0x400

 typedef struct RxTxStats {
     uint64_t rx_bytes;
     uint64_t tx_bytes;

     uint64_t rx;
     uint64_t rx_bcast;
     uint64_t rx_mcast;
 } RxTxStats;

 #define TYPE_XGMAC "xgmac"
 OBJECT_DECLARE_SIMPLE_TYPE(XgmacState, XGMAC)

 struct XgmacState {
     SysBusDevice parent_obj;

     MemoryRegion iomem;
     qemu_irq sbd_irq;
     qemu_irq pmt_irq;
     qemu_irq mci_irq;
     NICState *nic;
     NICConf conf;

     struct RxTxStats stats;
     uint32_t regs[R_MAX];
 };

 static const VMStateDescription vmstate_rxtx_stats = {
     .name = "xgmac_stats",
     .version_id = 1,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(rx_bytes, RxTxStats),
         VMSTATE_UINT64(tx_bytes, RxTxStats),
         VMSTATE_UINT64(rx, RxTxStats),
         VMSTATE_UINT64(rx_bcast, RxTxStats),
         VMSTATE_UINT64(rx_mcast, RxTxStats),
         VMSTATE_END_OF_LIST()
     }
 };

 static const VMStateDescription vmstate_xgmac = {
     .name = "xgmac",
     .version_id = 1,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_STRUCT(stats, XgmacState, 0, vmstate_rxtx_stats, RxTxStats),
         VMSTATE_UINT32_ARRAY(regs, XgmacState, R_MAX),
         VMSTATE_END_OF_LIST()
     }
 };

 static void xgmac_read_desc(XgmacState *s, struct desc *d, int rx)
 {
     uint32_t addr = rx ? s->regs[DMA_CUR_RX_DESC_ADDR] :
         s->regs[DMA_CUR_TX_DESC_ADDR];
     cpu_physical_memory_read(addr, d, sizeof(*d));
 }

 static void xgmac_write_desc(XgmacState *s, struct desc *d, int rx)
 {
     int reg = rx ? DMA_CUR_RX_DESC_ADDR : DMA_CUR_TX_DESC_ADDR;
     uint32_t addr = s->regs[reg];

     if (!rx && (d->ctl_stat & 0x00200000)) {
         s->regs[reg] = s->regs[DMA_TX_BASE_ADDR];
     } else if (rx && (d->buffer1_size & 0x8000)) {
         s->regs[reg] = s->regs[DMA_RCV_BASE_ADDR];
     } else {
         s->regs[reg] += sizeof(*d);
     }
     cpu_physical_memory_write(addr, d, sizeof(*d));
 }

 static void xgmac_enet_send(XgmacState *s)
 {
     struct desc bd;
     int frame_size;
     int len;
     uint8_t frame[8192];
     uint8_t *ptr;

     ptr = frame;
     frame_size = 0;
     while (1) {
         xgmac_read_desc(s, &bd, 0);
         if ((bd.ctl_stat & 0x80000000) == 0) {
             /* Run out of descriptors to transmit.  */
             break;
         }
         len = (bd.buffer1_size & 0xfff) + (bd.buffer2_size & 0xfff);

         /*
          * FIXME: these cases of malformed tx descriptors (bad sizes)
          * should probably be reported back to the guest somehow
          * rather than simply silently stopping processing, but we
          * don't know what the hardware does in this situation.
          * This will only happen for buggy guests anyway.
          */
         if ((bd.buffer1_size & 0xfff) > 2048) {
             DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
                         "xgmac buffer 1 len on send > 2048 (0x%x)\n",
                          __func__, bd.buffer1_size & 0xfff);
             break;
         }
         if ((bd.buffer2_size & 0xfff) != 0) {
             DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
                         "xgmac buffer 2 len on send != 0 (0x%x)\n",
                         __func__, bd.buffer2_size & 0xfff);
             break;
         }
         if (frame_size + len >= sizeof(frame)) {
             DEBUGF_BRK("qemu:%s: buffer overflow %d read into %zu "
                         "buffer\n" , __func__, frame_size + len, sizeof(frame));
             DEBUGF_BRK("qemu:%s: buffer1.size=%d; buffer2.size=%d\n",
                         __func__, bd.buffer1_size, bd.buffer2_size);
             break;
         }

         cpu_physical_memory_read(bd.buffer1_addr, ptr, len);
         ptr += len;
         frame_size += len;
         if (bd.ctl_stat & 0x20000000) {
             /* Last buffer in frame.  */
             qemu_send_packet(qemu_get_queue(s->nic), frame, len);
             ptr = frame;
             frame_size = 0;
             s->regs[DMA_STATUS] |= DMA_STATUS_TI | DMA_STATUS_NIS;
         }
         bd.ctl_stat &= ~0x80000000;
         /* Write back the modified descriptor.  */
         xgmac_write_desc(s, &bd, 0);
     }
 }

 static void enet_update_irq(XgmacState *s)
 {
     int stat = s->regs[DMA_STATUS] & s->regs[DMA_INTR_ENA];
     qemu_set_irq(s->sbd_irq, !!stat);
 }

 static uint64_t enet_read(void *opaque, hwaddr addr, unsigned size)
 {
     XgmacState *s = opaque;
     uint64_t r = 0;
     addr >>= 2;

     switch (addr) {
     case XGMAC_VERSION:
         r = 0x1012;
         break;
     default:
         if (addr < ARRAY_SIZE(s->regs)) {
             r = s->regs[addr];
         }
         break;
     }
     return r;
 }

 static void enet_write(void *opaque, hwaddr addr,
                        uint64_t value, unsigned size)
 {
     XgmacState *s = opaque;

     addr >>= 2;
     switch (addr) {
     case DMA_BUS_MODE:
         s->regs[DMA_BUS_MODE] = value & ~0x1;
         break;
     case DMA_XMT_POLL_DEMAND:
         xgmac_enet_send(s);
         break;
     case DMA_STATUS:
         s->regs[DMA_STATUS] = s->regs[DMA_STATUS] & ~value;
         break;
     case DMA_RCV_BASE_ADDR:
         s->regs[DMA_RCV_BASE_ADDR] = s->regs[DMA_CUR_RX_DESC_ADDR] = value;
         break;
     case DMA_TX_BASE_ADDR:
         s->regs[DMA_TX_BASE_ADDR] = s->regs[DMA_CUR_TX_DESC_ADDR] = value;
         break;
     default:
         if (addr < ARRAY_SIZE(s->regs)) {
             s->regs[addr] = value;
         }
         break;
     }
     enet_update_irq(s);
 }

 static const MemoryRegionOps enet_mem_ops = {
     .read = enet_read,
     .write = enet_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };

 static int eth_can_rx(XgmacState *s)
 {
     /* RX enabled?  */
     return s->regs[DMA_CONTROL] & DMA_CONTROL_SR;
 }

 static ssize_t eth_rx(NetClientState *nc, const uint8_t *buf, size_t size)
 {
     XgmacState *s = qemu_get_nic_opaque(nc);
     static const unsigned char sa_bcast[6] = {0xff, 0xff, 0xff,
                                               0xff, 0xff, 0xff};
     int unicast, broadcast, multicast;
     struct desc bd;
     ssize_t ret;

     if (!eth_can_rx(s)) {
         return -1;
     }
     unicast = ~buf[0] & 0x1;
     broadcast = memcmp(buf, sa_bcast, 6) == 0;
     multicast = !unicast && !broadcast;
     if (size < 12) {
         s->regs[DMA_STATUS] |= DMA_STATUS_RI | DMA_STATUS_NIS;
         ret = -1;
         goto out;
     }

     xgmac_read_desc(s, &bd, 1);
     if ((bd.ctl_stat & 0x80000000) == 0) {
         s->regs[DMA_STATUS] |= DMA_STATUS_RU | DMA_STATUS_AIS;
         ret = size;
         goto out;
     }

     cpu_physical_memory_write(bd.buffer1_addr, buf, size);

     /* Add in the 4 bytes for crc (the real hw returns length incl crc) */
     size += 4;
     bd.ctl_stat = (size << 16) | 0x300;
     xgmac_write_desc(s, &bd, 1);

     s->stats.rx_bytes += size;
     s->stats.rx++;
     if (multicast) {
         s->stats.rx_mcast++;
     } else if (broadcast) {
         s->stats.rx_bcast++;
     }

     s->regs[DMA_STATUS] |= DMA_STATUS_RI | DMA_STATUS_NIS;
     ret = size;

 out:
     enet_update_irq(s);
     return ret;
 }

 static NetClientInfo net_xgmac_enet_info = {
     .type = NET_CLIENT_DRIVER_NIC,
     .size = sizeof(NICState),
     .receive = eth_rx,
 };

 static void xgmac_enet_realize(DeviceState *dev, Error **errp)
 {
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     XgmacState *s = XGMAC(dev);

     memory_region_init_io(&s->iomem, OBJECT(s), &enet_mem_ops, s,
                           "xgmac", 0x1000);
     sysbus_init_mmio(sbd, &s->iomem);
     sysbus_init_irq(sbd, &s->sbd_irq);
     sysbus_init_irq(sbd, &s->pmt_irq);
     sysbus_init_irq(sbd, &s->mci_irq);

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

     s->regs[XGMAC_ADDR_HIGH(0)] = (s->conf.macaddr.a[5] << 8) |
                                    s->conf.macaddr.a[4];
     s->regs[XGMAC_ADDR_LOW(0)] = (s->conf.macaddr.a[3] << 24) |
                                  (s->conf.macaddr.a[2] << 16) |
                                  (s->conf.macaddr.a[1] << 8) |
                                   s->conf.macaddr.a[0];
 }

 static Property xgmac_properties[] = {
     DEFINE_NIC_PROPERTIES(XgmacState, conf),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void xgmac_enet_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->realize = xgmac_enet_realize;
     dc->vmsd = &vmstate_xgmac;
     device_class_set_props(dc, xgmac_properties);
 }

 static const TypeInfo xgmac_enet_info = {
     .name          = TYPE_XGMAC,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(XgmacState),
     .class_init    = xgmac_enet_class_init,
 };

 static void xgmac_enet_register_types(void)
 {
     type_register_static(&xgmac_enet_info);
 }

 type_init(xgmac_enet_register_types)
	/*
	* QEMU model of XGMAC Ethernet.
	*
	* derived from the Xilinx AXI-Ethernet by Edgar E. Iglesias.
	*
	* Copyright (c) 2011 Calxeda, Inc.
	*
	* 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/irq.h"
	#include "hw/qdev-properties.h"
	#include "hw/sysbus.h"
	#include "migration/vmstate.h"
	#include "qemu/module.h"
	#include "net/net.h"
	#include "qom/object.h"

	#ifdef DEBUG_XGMAC
	#define DEBUGF_BRK(message, args...) do { \
	fprintf(stderr, (message), ## args); \
	} while (0)
	#else
	#define DEBUGF_BRK(message, args...) do { } while (0)
	#endif

	#define XGMAC_CONTROL 0x00000000 /* MAC Configuration */
	#define XGMAC_FRAME_FILTER 0x00000001 /* MAC Frame Filter */
	#define XGMAC_FLOW_CTRL 0x00000006 /* MAC Flow Control */
	#define XGMAC_VLAN_TAG 0x00000007 /* VLAN Tags */
	#define XGMAC_VERSION 0x00000008 /* Version */
	/* VLAN tag for insertion or replacement into tx frames */
	#define XGMAC_VLAN_INCL 0x00000009
	#define XGMAC_LPI_CTRL 0x0000000a /* LPI Control and Status */
	#define XGMAC_LPI_TIMER 0x0000000b /* LPI Timers Control */
	#define XGMAC_TX_PACE 0x0000000c /* Transmit Pace and Stretch */
	#define XGMAC_VLAN_HASH 0x0000000d /* VLAN Hash Table */
	#define XGMAC_DEBUG 0x0000000e /* Debug */
	#define XGMAC_INT_STATUS 0x0000000f /* Interrupt and Control */
	/* HASH table registers */
	#define XGMAC_HASH(n) ((0x00000300/4) + (n))
	#define XGMAC_NUM_HASH 16
	/* Operation Mode */
	#define XGMAC_OPMODE (0x00000400/4)
	/* Remote Wake-Up Frame Filter */
	#define XGMAC_REMOTE_WAKE (0x00000700/4)
	/* PMT Control and Status */
	#define XGMAC_PMT (0x00000704/4)

	#define XGMAC_ADDR_HIGH(reg) (0x00000010+((reg) * 2))
	#define XGMAC_ADDR_LOW(reg) (0x00000011+((reg) * 2))

	#define DMA_BUS_MODE 0x000003c0 /* Bus Mode */
	#define DMA_XMT_POLL_DEMAND 0x000003c1 /* Transmit Poll Demand */
	#define DMA_RCV_POLL_DEMAND 0x000003c2 /* Received Poll Demand */
	#define DMA_RCV_BASE_ADDR 0x000003c3 /* Receive List Base */
	#define DMA_TX_BASE_ADDR 0x000003c4 /* Transmit List Base */
	#define DMA_STATUS 0x000003c5 /* Status Register */
	#define DMA_CONTROL 0x000003c6 /* Ctrl (Operational Mode) */
	#define DMA_INTR_ENA 0x000003c7 /* Interrupt Enable */
	#define DMA_MISSED_FRAME_CTR 0x000003c8 /* Missed Frame Counter */
	/* Receive Interrupt Watchdog Timer */
	#define DMA_RI_WATCHDOG_TIMER 0x000003c9
	#define DMA_AXI_BUS 0x000003ca /* AXI Bus Mode */
	#define DMA_AXI_STATUS 0x000003cb /* AXI Status */
	#define DMA_CUR_TX_DESC_ADDR 0x000003d2 /* Current Host Tx Descriptor */
	#define DMA_CUR_RX_DESC_ADDR 0x000003d3 /* Current Host Rx Descriptor */
	#define DMA_CUR_TX_BUF_ADDR 0x000003d4 /* Current Host Tx Buffer */
	#define DMA_CUR_RX_BUF_ADDR 0x000003d5 /* Current Host Rx Buffer */
	#define DMA_HW_FEATURE 0x000003d6 /* Enabled Hardware Features */

	/* DMA Status register defines */
	#define DMA_STATUS_GMI 0x08000000 /* MMC interrupt */
	#define DMA_STATUS_GLI 0x04000000 /* GMAC Line interface int */
	#define DMA_STATUS_EB_MASK 0x00380000 /* Error Bits Mask */
	#define DMA_STATUS_EB_TX_ABORT 0x00080000 /* Error Bits - TX Abort */
	#define DMA_STATUS_EB_RX_ABORT 0x00100000 /* Error Bits - RX Abort */
	#define DMA_STATUS_TS_MASK 0x00700000 /* Transmit Process State */
	#define DMA_STATUS_TS_SHIFT 20
	#define DMA_STATUS_RS_MASK 0x000e0000 /* Receive Process State */
	#define DMA_STATUS_RS_SHIFT 17
	#define DMA_STATUS_NIS 0x00010000 /* Normal Interrupt Summary */
	#define DMA_STATUS_AIS 0x00008000 /* Abnormal Interrupt Summary */
	#define DMA_STATUS_ERI 0x00004000 /* Early Receive Interrupt */
	#define DMA_STATUS_FBI 0x00002000 /* Fatal Bus Error Interrupt */
	#define DMA_STATUS_ETI 0x00000400 /* Early Transmit Interrupt */
	#define DMA_STATUS_RWT 0x00000200 /* Receive Watchdog Timeout */
	#define DMA_STATUS_RPS 0x00000100 /* Receive Process Stopped */
	#define DMA_STATUS_RU 0x00000080 /* Receive Buffer Unavailable */
	#define DMA_STATUS_RI 0x00000040 /* Receive Interrupt */
	#define DMA_STATUS_UNF 0x00000020 /* Transmit Underflow */
	#define DMA_STATUS_OVF 0x00000010 /* Receive Overflow */
	#define DMA_STATUS_TJT 0x00000008 /* Transmit Jabber Timeout */
	#define DMA_STATUS_TU 0x00000004 /* Transmit Buffer Unavailable */
	#define DMA_STATUS_TPS 0x00000002 /* Transmit Process Stopped */
	#define DMA_STATUS_TI 0x00000001 /* Transmit Interrupt */

	/* DMA Control register defines */
	#define DMA_CONTROL_ST 0x00002000 /* Start/Stop Transmission */
	#define DMA_CONTROL_SR 0x00000002 /* Start/Stop Receive */
	#define DMA_CONTROL_DFF 0x01000000 /* Disable flush of rx frames */

	struct desc {
	uint32_t ctl_stat;
	uint16_t buffer1_size;
	uint16_t buffer2_size;
	uint32_t buffer1_addr;
	uint32_t buffer2_addr;
	uint32_t ext_stat;
	uint32_t res[3];
	};

	#define R_MAX 0x400

	typedef struct RxTxStats {
	uint64_t rx_bytes;
	uint64_t tx_bytes;

	uint64_t rx;
	uint64_t rx_bcast;
	uint64_t rx_mcast;
	} RxTxStats;

	#define TYPE_XGMAC "xgmac"
	OBJECT_DECLARE_SIMPLE_TYPE(XgmacState, XGMAC)

	struct XgmacState {
	SysBusDevice parent_obj;

	MemoryRegion iomem;
	qemu_irq sbd_irq;
	qemu_irq pmt_irq;
	qemu_irq mci_irq;
	NICState *nic;
	NICConf conf;

	struct RxTxStats stats;
	uint32_t regs[R_MAX];
	};

	static const VMStateDescription vmstate_rxtx_stats = {
	.name = "xgmac_stats",
	.version_id = 1,
	.minimum_version_id = 1,
	.fields = (VMStateField[]) {
	VMSTATE_UINT64(rx_bytes, RxTxStats),
	VMSTATE_UINT64(tx_bytes, RxTxStats),
	VMSTATE_UINT64(rx, RxTxStats),
	VMSTATE_UINT64(rx_bcast, RxTxStats),
	VMSTATE_UINT64(rx_mcast, RxTxStats),
	VMSTATE_END_OF_LIST()
	}
	};

	static const VMStateDescription vmstate_xgmac = {
	.name = "xgmac",
	.version_id = 1,
	.minimum_version_id = 1,
	.fields = (VMStateField[]) {
	VMSTATE_STRUCT(stats, XgmacState, 0, vmstate_rxtx_stats, RxTxStats),
	VMSTATE_UINT32_ARRAY(regs, XgmacState, R_MAX),
	VMSTATE_END_OF_LIST()
	}
	};

	static void xgmac_read_desc(XgmacState s, struct desc d, int rx)
	{
	uint32_t addr = rx ? s->regs[DMA_CUR_RX_DESC_ADDR] :
	s->regs[DMA_CUR_TX_DESC_ADDR];
	cpu_physical_memory_read(addr, d, sizeof(*d));
	}

	static void xgmac_write_desc(XgmacState s, struct desc d, int rx)
	{
	int reg = rx ? DMA_CUR_RX_DESC_ADDR : DMA_CUR_TX_DESC_ADDR;
	uint32_t addr = s->regs[reg];

	if (!rx && (d->ctl_stat & 0x00200000)) {
	s->regs[reg] = s->regs[DMA_TX_BASE_ADDR];
	} else if (rx && (d->buffer1_size & 0x8000)) {
	s->regs[reg] = s->regs[DMA_RCV_BASE_ADDR];
	} else {
	s->regs[reg] += sizeof(*d);
	}
	cpu_physical_memory_write(addr, d, sizeof(*d));
	}

	static void xgmac_enet_send(XgmacState *s)
	{
	struct desc bd;
	int frame_size;
	int len;
	uint8_t frame[8192];
	uint8_t *ptr;

	ptr = frame;
	frame_size = 0;
	while (1) {
	xgmac_read_desc(s, &bd, 0);
	if ((bd.ctl_stat & 0x80000000) == 0) {
	/* Run out of descriptors to transmit. */
	break;
	}
	len = (bd.buffer1_size & 0xfff) + (bd.buffer2_size & 0xfff);

	/*
	* FIXME: these cases of malformed tx descriptors (bad sizes)
	* should probably be reported back to the guest somehow
	* rather than simply silently stopping processing, but we
	* don't know what the hardware does in this situation.
	* This will only happen for buggy guests anyway.
	*/
	if ((bd.buffer1_size & 0xfff) > 2048) {
	DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
	"xgmac buffer 1 len on send > 2048 (0x%x)\n",
	__func__, bd.buffer1_size & 0xfff);
	break;
	}
	if ((bd.buffer2_size & 0xfff) != 0) {
	DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
	"xgmac buffer 2 len on send != 0 (0x%x)\n",
	__func__, bd.buffer2_size & 0xfff);
	break;
	}
	if (frame_size + len >= sizeof(frame)) {
	DEBUGF_BRK("qemu:%s: buffer overflow %d read into %zu "
	"buffer\n" , __func__, frame_size + len, sizeof(frame));
	DEBUGF_BRK("qemu:%s: buffer1.size=%d; buffer2.size=%d\n",
	__func__, bd.buffer1_size, bd.buffer2_size);
	break;
	}

	cpu_physical_memory_read(bd.buffer1_addr, ptr, len);
	ptr += len;
	frame_size += len;
	if (bd.ctl_stat & 0x20000000) {
	/* Last buffer in frame. */
	qemu_send_packet(qemu_get_queue(s->nic), frame, len);
	ptr = frame;
	frame_size = 0;
	s->regs[DMA_STATUS] \|= DMA_STATUS_TI \| DMA_STATUS_NIS;
	}
	bd.ctl_stat &= ~0x80000000;
	/* Write back the modified descriptor. */
	xgmac_write_desc(s, &bd, 0);
	}
	}

	static void enet_update_irq(XgmacState *s)
	{
	int stat = s->regs[DMA_STATUS] & s->regs[DMA_INTR_ENA];
	qemu_set_irq(s->sbd_irq, !!stat);
	}

	static uint64_t enet_read(void *opaque, hwaddr addr, unsigned size)
	{
	XgmacState *s = opaque;
	uint64_t r = 0;
	addr >>= 2;

	switch (addr) {
	case XGMAC_VERSION:
	r = 0x1012;
	break;
	default:
	if (addr < ARRAY_SIZE(s->regs)) {
	r = s->regs[addr];
	}
	break;
	}
	return r;
	}

	static void enet_write(void *opaque, hwaddr addr,
	uint64_t value, unsigned size)
	{
	XgmacState *s = opaque;

	addr >>= 2;
	switch (addr) {
	case DMA_BUS_MODE:
	s->regs[DMA_BUS_MODE] = value & ~0x1;
	break;
	case DMA_XMT_POLL_DEMAND:
	xgmac_enet_send(s);
	break;
	case DMA_STATUS:
	s->regs[DMA_STATUS] = s->regs[DMA_STATUS] & ~value;
	break;
	case DMA_RCV_BASE_ADDR:
	s->regs[DMA_RCV_BASE_ADDR] = s->regs[DMA_CUR_RX_DESC_ADDR] = value;
	break;
	case DMA_TX_BASE_ADDR:
	s->regs[DMA_TX_BASE_ADDR] = s->regs[DMA_CUR_TX_DESC_ADDR] = value;
	break;
	default:
	if (addr < ARRAY_SIZE(s->regs)) {
	s->regs[addr] = value;
	}
	break;
	}
	enet_update_irq(s);
	}

	static const MemoryRegionOps enet_mem_ops = {
	.read = enet_read,
	.write = enet_write,
	.endianness = DEVICE_LITTLE_ENDIAN,
	};

	static int eth_can_rx(XgmacState *s)
	{
	/* RX enabled? */
	return s->regs[DMA_CONTROL] & DMA_CONTROL_SR;
	}

	static ssize_t eth_rx(NetClientState nc, const uint8_t buf, size_t size)
	{
	XgmacState *s = qemu_get_nic_opaque(nc);
	static const unsigned char sa_bcast[6] = {0xff, 0xff, 0xff,
	0xff, 0xff, 0xff};
	int unicast, broadcast, multicast;
	struct desc bd;
	ssize_t ret;

	if (!eth_can_rx(s)) {
	return -1;
	}
	unicast = ~buf[0] & 0x1;
	broadcast = memcmp(buf, sa_bcast, 6) == 0;
	multicast = !unicast && !broadcast;
	if (size < 12) {
	s->regs[DMA_STATUS] \|= DMA_STATUS_RI \| DMA_STATUS_NIS;
	ret = -1;
	goto out;
	}

	xgmac_read_desc(s, &bd, 1);
	if ((bd.ctl_stat & 0x80000000) == 0) {
	s->regs[DMA_STATUS] \|= DMA_STATUS_RU \| DMA_STATUS_AIS;
	ret = size;
	goto out;
	}

	cpu_physical_memory_write(bd.buffer1_addr, buf, size);

	/* Add in the 4 bytes for crc (the real hw returns length incl crc) */
	size += 4;
	bd.ctl_stat = (size << 16) \| 0x300;
	xgmac_write_desc(s, &bd, 1);

	s->stats.rx_bytes += size;
	s->stats.rx++;
	if (multicast) {
	s->stats.rx_mcast++;
	} else if (broadcast) {
	s->stats.rx_bcast++;
	}

	s->regs[DMA_STATUS] \|= DMA_STATUS_RI \| DMA_STATUS_NIS;
	ret = size;

	out:
	enet_update_irq(s);
	return ret;
	}

	static NetClientInfo net_xgmac_enet_info = {
	.type = NET_CLIENT_DRIVER_NIC,
	.size = sizeof(NICState),
	.receive = eth_rx,
	};

	static void xgmac_enet_realize(DeviceState dev, Error *errp)
	{
	SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
	XgmacState *s = XGMAC(dev);

	memory_region_init_io(&s->iomem, OBJECT(s), &enet_mem_ops, s,
	"xgmac", 0x1000);
	sysbus_init_mmio(sbd, &s->iomem);
	sysbus_init_irq(sbd, &s->sbd_irq);
	sysbus_init_irq(sbd, &s->pmt_irq);
	sysbus_init_irq(sbd, &s->mci_irq);

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

	s->regs[XGMAC_ADDR_HIGH(0)] = (s->conf.macaddr.a[5] << 8) \|
	s->conf.macaddr.a[4];
	s->regs[XGMAC_ADDR_LOW(0)] = (s->conf.macaddr.a[3] << 24) \|
	(s->conf.macaddr.a[2] << 16) \|
	(s->conf.macaddr.a[1] << 8) \|
	s->conf.macaddr.a[0];
	}

	static Property xgmac_properties[] = {
	DEFINE_NIC_PROPERTIES(XgmacState, conf),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void xgmac_enet_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->realize = xgmac_enet_realize;
	dc->vmsd = &vmstate_xgmac;
	device_class_set_props(dc, xgmac_properties);
	}

	static const TypeInfo xgmac_enet_info = {
	.name = TYPE_XGMAC,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(XgmacState),
	.class_init = xgmac_enet_class_init,
	};

	static void xgmac_enet_register_types(void)
	{
	type_register_static(&xgmac_enet_info);
	}

	type_init(xgmac_enet_register_types)