gem5/dev/ns_gige.cc

/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @file
 * Device module for modelling the National Semiconductor
 * DP83820 ethernet controller.  Does not support priority queueing
 */
#include <cstdio>
#include <deque>
#include <string>

#include "base/inet.hh"
#include "cpu/exec_context.hh"
#include "dev/etherlink.hh"
#include "dev/ns_gige.hh"
#include "dev/pciconfigall.hh"
#include "mem/bus/bus.hh"
#include "mem/bus/dma_interface.hh"
#include "mem/bus/pio_interface.hh"
#include "mem/bus/pio_interface_impl.hh"
#include "mem/functional/memory_control.hh"
#include "mem/functional/physical.hh"
#include "sim/builder.hh"
#include "sim/debug.hh"
#include "sim/host.hh"
#include "sim/stats.hh"
#include "targetarch/vtophys.hh"

const char *NsRxStateStrings[] =
{
    "rxIdle",
    "rxDescRefr",
    "rxDescRead",
    "rxFifoBlock",
    "rxFragWrite",
    "rxDescWrite",
    "rxAdvance"
};

const char *NsTxStateStrings[] =
{
    "txIdle",
    "txDescRefr",
    "txDescRead",
    "txFifoBlock",
    "txFragRead",
    "txDescWrite",
    "txAdvance"
};

const char *NsDmaState[] =
{
    "dmaIdle",
    "dmaReading",
    "dmaWriting",
    "dmaReadWaiting",
    "dmaWriteWaiting"
};

using namespace std;
using namespace Net;

///////////////////////////////////////////////////////////////////////
//
// NSGigE PCI Device
//
NSGigE::NSGigE(Params *p)
    : PciDev(p), ioEnable(false),
      txFifo(p->tx_fifo_size), rxFifo(p->rx_fifo_size),
      txPacket(0), rxPacket(0), txPacketBufPtr(NULL), rxPacketBufPtr(NULL),
      txXferLen(0), rxXferLen(0), clock(p->clock),
      txState(txIdle), txEnable(false), CTDD(false),
      txFragPtr(0), txDescCnt(0), txDmaState(dmaIdle), rxState(rxIdle),
      rxEnable(false), CRDD(false), rxPktBytes(0),
      rxFragPtr(0), rxDescCnt(0), rxDmaState(dmaIdle), extstsEnable(false),
      rxDmaReadEvent(this), rxDmaWriteEvent(this),
      txDmaReadEvent(this), txDmaWriteEvent(this),
      dmaDescFree(p->dma_desc_free), dmaDataFree(p->dma_data_free),
      txDelay(p->tx_delay), rxDelay(p->rx_delay),
      rxKickTick(0), txKickTick(0),
      txEvent(this), rxFilterEnable(p->rx_filter), acceptBroadcast(false),
      acceptMulticast(false), acceptUnicast(false),
      acceptPerfect(false), acceptArp(false),
      physmem(p->pmem), intrTick(0), cpuPendingIntr(false),
      intrEvent(0), interface(0)
{
    if (p->header_bus) {
        pioInterface = newPioInterface(name(), p->hier,
                                       p->header_bus, this,
                                       &NSGigE::cacheAccess);

        pioLatency = p->pio_latency * p->header_bus->clockRate;

        if (p->payload_bus)
            dmaInterface = new DMAInterface<Bus>(name() + ".dma",
                                                 p->header_bus,
                                                 p->payload_bus, 1,
                                                 p->dma_no_allocate);
        else
            dmaInterface = new DMAInterface<Bus>(name() + ".dma",
                                                 p->header_bus,
                                                 p->header_bus, 1,
                                                 p->dma_no_allocate);
    } else if (p->payload_bus) {
        pioInterface = newPioInterface(name(), p->hier,
                                       p->payload_bus, this,
                                       &NSGigE::cacheAccess);

        pioLatency = p->pio_latency * p->payload_bus->clockRate;

        dmaInterface = new DMAInterface<Bus>(name() + ".dma",
                                             p->payload_bus,
                                             p->payload_bus, 1,
                                             p->dma_no_allocate);
    }


    intrDelay = p->intr_delay;
    dmaReadDelay = p->dma_read_delay;
    dmaWriteDelay = p->dma_write_delay;
    dmaReadFactor = p->dma_read_factor;
    dmaWriteFactor = p->dma_write_factor;

    regsReset();
    memcpy(&rom.perfectMatch, p->eaddr.bytes(), ETH_ADDR_LEN);
}

NSGigE::~NSGigE()
{}

void
NSGigE::regStats()
{
    txBytes
        .name(name() + ".txBytes")
        .desc("Bytes Transmitted")
        .prereq(txBytes)
        ;

    rxBytes
        .name(name() + ".rxBytes")
        .desc("Bytes Received")
        .prereq(rxBytes)
        ;

    txPackets
        .name(name() + ".txPackets")
        .desc("Number of Packets Transmitted")
        .prereq(txBytes)
        ;

    rxPackets
        .name(name() + ".rxPackets")
        .desc("Number of Packets Received")
        .prereq(rxBytes)
        ;

    txIpChecksums
        .name(name() + ".txIpChecksums")
        .desc("Number of tx IP Checksums done by device")
        .precision(0)
        .prereq(txBytes)
        ;

    rxIpChecksums
        .name(name() + ".rxIpChecksums")
        .desc("Number of rx IP Checksums done by device")
        .precision(0)
        .prereq(rxBytes)
        ;

    txTcpChecksums
        .name(name() + ".txTcpChecksums")
        .desc("Number of tx TCP Checksums done by device")
        .precision(0)
        .prereq(txBytes)
        ;

    rxTcpChecksums
        .name(name() + ".rxTcpChecksums")
        .desc("Number of rx TCP Checksums done by device")
        .precision(0)
        .prereq(rxBytes)
        ;

    txUdpChecksums
        .name(name() + ".txUdpChecksums")
        .desc("Number of tx UDP Checksums done by device")
        .precision(0)
        .prereq(txBytes)
        ;

    rxUdpChecksums
        .name(name() + ".rxUdpChecksums")
        .desc("Number of rx UDP Checksums done by device")
        .precision(0)
        .prereq(rxBytes)
        ;

    descDmaReads
        .name(name() + ".descDMAReads")
        .desc("Number of descriptors the device read w/ DMA")
        .precision(0)
        ;

    descDmaWrites
        .name(name() + ".descDMAWrites")
        .desc("Number of descriptors the device wrote w/ DMA")
        .precision(0)
        ;

    descDmaRdBytes
        .name(name() + ".descDmaReadBytes")
        .desc("number of descriptor bytes read w/ DMA")
        .precision(0)
        ;

   descDmaWrBytes
        .name(name() + ".descDmaWriteBytes")
        .desc("number of descriptor bytes write w/ DMA")
        .precision(0)
        ;

    txBandwidth
        .name(name() + ".txBandwidth")
        .desc("Transmit Bandwidth (bits/s)")
        .precision(0)
        .prereq(txBytes)
        ;

    rxBandwidth
        .name(name() + ".rxBandwidth")
        .desc("Receive Bandwidth (bits/s)")
        .precision(0)
        .prereq(rxBytes)
        ;

    totBandwidth
        .name(name() + ".totBandwidth")
        .desc("Total Bandwidth (bits/s)")
        .precision(0)
        .prereq(totBytes)
        ;

    totPackets
        .name(name() + ".totPackets")
        .desc("Total Packets")
        .precision(0)
        .prereq(totBytes)
        ;

    totBytes
        .name(name() + ".totBytes")
        .desc("Total Bytes")
        .precision(0)
        .prereq(totBytes)
        ;

    totPacketRate
        .name(name() + ".totPPS")
        .desc("Total Tranmission Rate (packets/s)")
        .precision(0)
        .prereq(totBytes)
        ;

    txPacketRate
        .name(name() + ".txPPS")
        .desc("Packet Tranmission Rate (packets/s)")
        .precision(0)
        .prereq(txBytes)
        ;

    rxPacketRate
        .name(name() + ".rxPPS")
        .desc("Packet Reception Rate (packets/s)")
        .precision(0)
        .prereq(rxBytes)
        ;

    postedSwi
        .name(name() + ".postedSwi")
        .desc("number of software interrupts posted to CPU")
        .precision(0)
        ;

    totalSwi
        .name(name() + ".totalSwi")
        .desc("number of total Swi written to ISR")
        .precision(0)
        ;

    coalescedSwi
        .name(name() + ".coalescedSwi")
        .desc("average number of Swi's coalesced into each post")
        .precision(0)
        ;

    postedRxIdle
        .name(name() + ".postedRxIdle")
        .desc("number of rxIdle interrupts posted to CPU")
        .precision(0)
        ;

    totalRxIdle
        .name(name() + ".totalRxIdle")
        .desc("number of total RxIdle written to ISR")
        .precision(0)
        ;

    coalescedRxIdle
        .name(name() + ".coalescedRxIdle")
        .desc("average number of RxIdle's coalesced into each post")
        .precision(0)
        ;

    postedRxOk
        .name(name() + ".postedRxOk")
        .desc("number of RxOk interrupts posted to CPU")
        .precision(0)
        ;

    totalRxOk
        .name(name() + ".totalRxOk")
        .desc("number of total RxOk written to ISR")
        .precision(0)
        ;

    coalescedRxOk
        .name(name() + ".coalescedRxOk")
        .desc("average number of RxOk's coalesced into each post")
        .precision(0)
        ;

    postedRxDesc
        .name(name() + ".postedRxDesc")
        .desc("number of RxDesc interrupts posted to CPU")
        .precision(0)
        ;

    totalRxDesc
        .name(name() + ".totalRxDesc")
        .desc("number of total RxDesc written to ISR")
        .precision(0)
        ;

    coalescedRxDesc
        .name(name() + ".coalescedRxDesc")
        .desc("average number of RxDesc's coalesced into each post")
        .precision(0)
        ;

    postedTxOk
        .name(name() + ".postedTxOk")
        .desc("number of TxOk interrupts posted to CPU")
        .precision(0)
        ;

    totalTxOk
        .name(name() + ".totalTxOk")
        .desc("number of total TxOk written to ISR")
        .precision(0)
        ;

    coalescedTxOk
        .name(name() + ".coalescedTxOk")
        .desc("average number of TxOk's coalesced into each post")
        .precision(0)
        ;

    postedTxIdle
        .name(name() + ".postedTxIdle")
        .desc("number of TxIdle interrupts posted to CPU")
        .precision(0)
        ;

    totalTxIdle
        .name(name() + ".totalTxIdle")
        .desc("number of total TxIdle written to ISR")
        .precision(0)
        ;

    coalescedTxIdle
        .name(name() + ".coalescedTxIdle")
        .desc("average number of TxIdle's coalesced into each post")
        .precision(0)
        ;

    postedTxDesc
        .name(name() + ".postedTxDesc")
        .desc("number of TxDesc interrupts posted to CPU")
        .precision(0)
        ;

    totalTxDesc
        .name(name() + ".totalTxDesc")
        .desc("number of total TxDesc written to ISR")
        .precision(0)
        ;

    coalescedTxDesc
        .name(name() + ".coalescedTxDesc")
        .desc("average number of TxDesc's coalesced into each post")
        .precision(0)
        ;

    postedRxOrn
        .name(name() + ".postedRxOrn")
        .desc("number of RxOrn posted to CPU")
        .precision(0)
        ;

    totalRxOrn
        .name(name() + ".totalRxOrn")
        .desc("number of total RxOrn written to ISR")
        .precision(0)
        ;

    coalescedRxOrn
        .name(name() + ".coalescedRxOrn")
        .desc("average number of RxOrn's coalesced into each post")
        .precision(0)
        ;

    coalescedTotal
        .name(name() + ".coalescedTotal")
        .desc("average number of interrupts coalesced into each post")
        .precision(0)
        ;

    postedInterrupts
        .name(name() + ".postedInterrupts")
        .desc("number of posts to CPU")
        .precision(0)
        ;

    droppedPackets
        .name(name() + ".droppedPackets")
        .desc("number of packets dropped")
        .precision(0)
        ;

    coalescedSwi = totalSwi / postedInterrupts;
    coalescedRxIdle = totalRxIdle / postedInterrupts;
    coalescedRxOk = totalRxOk / postedInterrupts;
    coalescedRxDesc = totalRxDesc / postedInterrupts;
    coalescedTxOk = totalTxOk / postedInterrupts;
    coalescedTxIdle = totalTxIdle / postedInterrupts;
    coalescedTxDesc = totalTxDesc / postedInterrupts;
    coalescedRxOrn = totalRxOrn / postedInterrupts;

    coalescedTotal = (totalSwi + totalRxIdle + totalRxOk + totalRxDesc +
                      totalTxOk + totalTxIdle + totalTxDesc +
                      totalRxOrn) / postedInterrupts;

    txBandwidth = txBytes * Stats::constant(8) / simSeconds;
    rxBandwidth = rxBytes * Stats::constant(8) / simSeconds;
    totBandwidth = txBandwidth + rxBandwidth;
    totBytes = txBytes + rxBytes;
    totPackets = txPackets + rxPackets;

    txPacketRate = txPackets / simSeconds;
    rxPacketRate = rxPackets / simSeconds;
}

/**
 * This is to read the PCI general configuration registers
 */
void
NSGigE::ReadConfig(int offset, int size, uint8_t *data)
{
    if (offset < PCI_DEVICE_SPECIFIC)
        PciDev::ReadConfig(offset, size, data);
    else
        panic("Device specific PCI config space not implemented!\n");
}

/**
 * This is to write to the PCI general configuration registers
 */
void
NSGigE::WriteConfig(int offset, int size, uint32_t data)
{
    if (offset < PCI_DEVICE_SPECIFIC)
        PciDev::WriteConfig(offset, size, data);
    else
        panic("Device specific PCI config space not implemented!\n");

    // Need to catch writes to BARs to update the PIO interface
    switch (offset) {
        // seems to work fine without all these PCI settings, but i
        // put in the IO to double check, an assertion will fail if we
        // need to properly implement it
      case PCI_COMMAND:
        if (config.data[offset] & PCI_CMD_IOSE)
            ioEnable = true;
        else
            ioEnable = false;

#if 0
        if (config.data[offset] & PCI_CMD_BME) {
            bmEnabled = true;
        }
        else {
            bmEnabled = false;
        }

        if (config.data[offset] & PCI_CMD_MSE) {
            memEnable = true;
        }
        else {
            memEnable = false;
        }
#endif
        break;

      case PCI0_BASE_ADDR0:
        if (BARAddrs[0] != 0) {
            if (pioInterface)
                pioInterface->addAddrRange(RangeSize(BARAddrs[0], BARSize[0]));

            BARAddrs[0] &= EV5::PAddrUncachedMask;
        }
        break;
      case PCI0_BASE_ADDR1:
        if (BARAddrs[1] != 0) {
            if (pioInterface)
                pioInterface->addAddrRange(RangeSize(BARAddrs[1], BARSize[1]));

            BARAddrs[1] &= EV5::PAddrUncachedMask;
        }
        break;
    }
}

/**
 * This reads the device registers, which are detailed in the NS83820
 * spec sheet
 */
Fault
NSGigE::read(MemReqPtr &req, uint8_t *data)
{
    assert(ioEnable);

    //The mask is to give you only the offset into the device register file
    Addr daddr = req->paddr & 0xfff;
    DPRINTF(EthernetPIO, "read  da=%#x pa=%#x va=%#x size=%d\n",
            daddr, req->paddr, req->vaddr, req->size);


    // there are some reserved registers, you can see ns_gige_reg.h and
    // the spec sheet for details
    if (daddr > LAST && daddr <=  RESERVED) {
        panic("Accessing reserved register");
    } else if (daddr > RESERVED && daddr <= 0x3FC) {
        ReadConfig(daddr & 0xff, req->size, data);
        return No_Fault;
    } else if (daddr >= MIB_START && daddr <= MIB_END) {
        // don't implement all the MIB's.  hopefully the kernel
        // doesn't actually DEPEND upon their values
        // MIB are just hardware stats keepers
        uint32_t &reg = *(uint32_t *) data;
        reg = 0;
        return No_Fault;
    } else if (daddr > 0x3FC)
        panic("Something is messed up!\n");

    switch (req->size) {
      case sizeof(uint32_t):
        {
            uint32_t &reg = *(uint32_t *)data;

            switch (daddr) {
              case CR:
                reg = regs.command;
                //these are supposed to be cleared on a read
                reg &= ~(CR_RXD | CR_TXD | CR_TXR | CR_RXR);
                break;

              case CFGR:
                reg = regs.config;
                break;

              case MEAR:
                reg = regs.mear;
                break;

              case PTSCR:
                reg = regs.ptscr;
                break;

              case ISR:
                reg = regs.isr;
                devIntrClear(ISR_ALL);
                break;

              case IMR:
                reg = regs.imr;
                break;

              case IER:
                reg = regs.ier;
                break;

              case IHR:
                reg = regs.ihr;
                break;

              case TXDP:
                reg = regs.txdp;
                break;

              case TXDP_HI:
                reg = regs.txdp_hi;
                break;

              case TX_CFG:
                reg = regs.txcfg;
                break;

              case GPIOR:
                reg = regs.gpior;
                break;

              case RXDP:
                reg = regs.rxdp;
                break;

              case RXDP_HI:
                reg = regs.rxdp_hi;
                break;

              case RX_CFG:
                reg = regs.rxcfg;
                break;

              case PQCR:
                reg = regs.pqcr;
                break;

              case WCSR:
                reg = regs.wcsr;
                break;

              case PCR:
                reg = regs.pcr;
                break;

                // see the spec sheet for how RFCR and RFDR work
                // basically, you write to RFCR to tell the machine
                // what you want to do next, then you act upon RFDR,
                // and the device will be prepared b/c of what you
                // wrote to RFCR
              case RFCR:
                reg = regs.rfcr;
                break;

              case RFDR:
                switch (regs.rfcr & RFCR_RFADDR) {
                  case 0x000:
                    reg = rom.perfectMatch[1];
                    reg = reg << 8;
                    reg += rom.perfectMatch[0];
                    break;
                  case 0x002:
                    reg = rom.perfectMatch[3] << 8;
                    reg += rom.perfectMatch[2];
                    break;
                  case 0x004:
                    reg = rom.perfectMatch[5] << 8;
                    reg += rom.perfectMatch[4];
                    break;
                  default:
                    panic("reading RFDR for something other than PMATCH!\n");
                    // didn't implement other RFDR functionality b/c
                    // driver didn't use it
                }
                break;

              case SRR:
                reg = regs.srr;
                break;

              case MIBC:
                reg = regs.mibc;
                reg &= ~(MIBC_MIBS | MIBC_ACLR);
                break;

              case VRCR:
                reg = regs.vrcr;
                break;

              case VTCR:
                reg = regs.vtcr;
                break;

              case VDR:
                reg = regs.vdr;
                break;

              case CCSR:
                reg = regs.ccsr;
                break;

              case TBICR:
                reg = regs.tbicr;
                break;

              case TBISR:
                reg = regs.tbisr;
                break;

              case TANAR:
                reg = regs.tanar;
                break;

              case TANLPAR:
                reg = regs.tanlpar;
                break;

              case TANER:
                reg = regs.taner;
                break;

              case TESR:
                reg = regs.tesr;
                break;

              case M5REG:
                reg = params()->m5reg;
                break;

              default:
                panic("reading unimplemented register: addr=%#x", daddr);
            }

            DPRINTF(EthernetPIO, "read from %#x: data=%d data=%#x\n",
                    daddr, reg, reg);
        }
        break;

      default:
        panic("accessing register with invalid size: addr=%#x, size=%d",
              daddr, req->size);
    }

    return No_Fault;
}

Fault
NSGigE::write(MemReqPtr &req, const uint8_t *data)
{
    assert(ioEnable);

    Addr daddr = req->paddr & 0xfff;
    DPRINTF(EthernetPIO, "write da=%#x pa=%#x va=%#x size=%d\n",
            daddr, req->paddr, req->vaddr, req->size);

    if (daddr > LAST && daddr <=  RESERVED) {
        panic("Accessing reserved register");
    } else if (daddr > RESERVED && daddr <= 0x3FC) {
        WriteConfig(daddr & 0xff, req->size, *(uint32_t *)data);
        return No_Fault;
    } else if (daddr > 0x3FC)
        panic("Something is messed up!\n");

    if (req->size == sizeof(uint32_t)) {
        uint32_t reg = *(uint32_t *)data;
        DPRINTF(EthernetPIO, "write data=%d data=%#x\n", reg, reg);

        switch (daddr) {
          case CR:
            regs.command = reg;
            if (reg & CR_TXD) {
                txEnable = false;
            } else if (reg & CR_TXE) {
                txEnable = true;

                // the kernel is enabling the transmit machine
                if (txState == txIdle)
                    txKick();
            }

            if (reg & CR_RXD) {
                rxEnable = false;
            } else if (reg & CR_RXE) {
                rxEnable = true;

                if (rxState == rxIdle)
                    rxKick();
            }

            if (reg & CR_TXR)
                txReset();

            if (reg & CR_RXR)
                rxReset();

            if (reg & CR_SWI)
                devIntrPost(ISR_SWI);

            if (reg & CR_RST) {
                txReset();
                rxReset();

                regsReset();
            }
            break;

          case CFGR:
            if (reg & CFGR_LNKSTS ||
                reg & CFGR_SPDSTS ||
                reg & CFGR_DUPSTS ||
                reg & CFGR_RESERVED ||
                reg & CFGR_T64ADDR ||
                reg & CFGR_PCI64_DET)
                panic("writing to read-only or reserved CFGR bits!\n");

            regs.config |= reg & ~(CFGR_LNKSTS | CFGR_SPDSTS | CFGR_DUPSTS |
                                   CFGR_RESERVED | CFGR_T64ADDR | CFGR_PCI64_DET);

// all these #if 0's are because i don't THINK the kernel needs to
// have these implemented. if there is a problem relating to one of
// these, you may need to add functionality in.
#if 0
            if (reg & CFGR_TBI_EN) ;
            if (reg & CFGR_MODE_1000) ;
#endif

            if (reg & CFGR_AUTO_1000)
                panic("CFGR_AUTO_1000 not implemented!\n");

#if 0
            if (reg & CFGR_PINT_DUPSTS ||
                reg & CFGR_PINT_LNKSTS ||
                reg & CFGR_PINT_SPDSTS)
                ;

            if (reg & CFGR_TMRTEST) ;
            if (reg & CFGR_MRM_DIS) ;
            if (reg & CFGR_MWI_DIS) ;

            if (reg & CFGR_T64ADDR)
                panic("CFGR_T64ADDR is read only register!\n");

            if (reg & CFGR_PCI64_DET)
                panic("CFGR_PCI64_DET is read only register!\n");

            if (reg & CFGR_DATA64_EN) ;
            if (reg & CFGR_M64ADDR) ;
            if (reg & CFGR_PHY_RST) ;
            if (reg & CFGR_PHY_DIS) ;
#endif

            if (reg & CFGR_EXTSTS_EN)
                extstsEnable = true;
            else
                extstsEnable = false;

#if 0
              if (reg & CFGR_REQALG) ;
              if (reg & CFGR_SB) ;
              if (reg & CFGR_POW) ;
              if (reg & CFGR_EXD) ;
              if (reg & CFGR_PESEL) ;
              if (reg & CFGR_BROM_DIS) ;
              if (reg & CFGR_EXT_125) ;
              if (reg & CFGR_BEM) ;
#endif
            break;

          case MEAR:
            regs.mear = reg;
            // since phy is completely faked, MEAR_MD* don't matter
            // and since the driver never uses MEAR_EE*, they don't
            // matter
#if 0
            if (reg & MEAR_EEDI) ;
            if (reg & MEAR_EEDO) ; // this one is read only
            if (reg & MEAR_EECLK) ;
            if (reg & MEAR_EESEL) ;
            if (reg & MEAR_MDIO) ;
            if (reg & MEAR_MDDIR) ;
            if (reg & MEAR_MDC) ;
#endif
            break;

          case PTSCR:
            regs.ptscr = reg & ~(PTSCR_RBIST_RDONLY);
            // these control BISTs for various parts of chip - we
            // don't care or do just fake that the BIST is done
            if (reg & PTSCR_RBIST_EN)
                regs.ptscr |= PTSCR_RBIST_DONE;
            if (reg & PTSCR_EEBIST_EN)
                regs.ptscr &= ~PTSCR_EEBIST_EN;
            if (reg & PTSCR_EELOAD_EN)
                regs.ptscr &= ~PTSCR_EELOAD_EN;
            break;

          case ISR: /* writing to the ISR has no effect */
            panic("ISR is a read only register!\n");

          case IMR:
            regs.imr = reg;
            devIntrChangeMask();
            break;

          case IER:
            regs.ier = reg;
            break;

          case IHR:
            regs.ihr = reg;
            /* not going to implement real interrupt holdoff */
            break;

          case TXDP:
            regs.txdp = (reg & 0xFFFFFFFC);
            assert(txState == txIdle);
            CTDD = false;
            break;

          case TXDP_HI:
            regs.txdp_hi = reg;
            break;

          case TX_CFG:
            regs.txcfg = reg;
#if 0
            if (reg & TX_CFG_CSI) ;
            if (reg & TX_CFG_HBI) ;
            if (reg & TX_CFG_MLB) ;
            if (reg & TX_CFG_ATP) ;
            if (reg & TX_CFG_ECRETRY) {
                /*
                 * this could easily be implemented, but considering
                 * the network is just a fake pipe, wouldn't make
                 * sense to do this
                 */
            }

            if (reg & TX_CFG_BRST_DIS) ;
#endif

#if 0
            /* we handle our own DMA, ignore the kernel's exhortations */
            if (reg & TX_CFG_MXDMA) ;
#endif

            // also, we currently don't care about fill/drain
            // thresholds though this may change in the future with
            // more realistic networks or a driver which changes it
            // according to feedback

            break;

          case GPIOR:
            regs.gpior = reg;
            /* these just control general purpose i/o pins, don't matter */
            break;

          case RXDP:
            regs.rxdp = reg;
            CRDD = false;
            break;

          case RXDP_HI:
            regs.rxdp_hi = reg;
            break;

          case RX_CFG:
            regs.rxcfg = reg;
#if 0
            if (reg & RX_CFG_AEP) ;
            if (reg & RX_CFG_ARP) ;
            if (reg & RX_CFG_STRIPCRC) ;
            if (reg & RX_CFG_RX_RD) ;
            if (reg & RX_CFG_ALP) ;
            if (reg & RX_CFG_AIRL) ;

            /* we handle our own DMA, ignore what kernel says about it */
            if (reg & RX_CFG_MXDMA) ;

            //also, we currently don't care about fill/drain thresholds
            //though this may change in the future with more realistic
            //networks or a driver which changes it according to feedback
            if (reg & (RX_CFG_DRTH | RX_CFG_DRTH0)) ;
#endif
            break;

          case PQCR:
            /* there is no priority queueing used in the linux 2.6 driver */
            regs.pqcr = reg;
            break;

          case WCSR:
            /* not going to implement wake on LAN */
            regs.wcsr = reg;
            break;

          case PCR:
            /* not going to implement pause control */
            regs.pcr = reg;
            break;

          case RFCR:
            regs.rfcr = reg;

            rxFilterEnable = (reg & RFCR_RFEN) ? true : false;
            acceptBroadcast = (reg & RFCR_AAB) ? true : false;
            acceptMulticast = (reg & RFCR_AAM) ? true : false;
            acceptUnicast = (reg & RFCR_AAU) ? true : false;
            acceptPerfect = (reg & RFCR_APM) ? true : false;
            acceptArp = (reg & RFCR_AARP) ? true : false;

#if 0
            if (reg & RFCR_APAT)
                panic("RFCR_APAT not implemented!\n");
#endif

            if (reg & RFCR_MHEN || reg & RFCR_UHEN)
                panic("hash filtering not implemented!\n");

            if (reg & RFCR_ULM)
                panic("RFCR_ULM not implemented!\n");

            break;

          case RFDR:
            panic("the driver never writes to RFDR, something is wrong!\n");

          case BRAR:
            panic("the driver never uses BRAR, something is wrong!\n");

          case BRDR:
            panic("the driver never uses BRDR, something is wrong!\n");

          case SRR:
            panic("SRR is read only register!\n");

          case MIBC:
            panic("the driver never uses MIBC, something is wrong!\n");

          case VRCR:
            regs.vrcr = reg;
            break;

          case VTCR:
            regs.vtcr = reg;
            break;

          case VDR:
            panic("the driver never uses VDR, something is wrong!\n");
            break;

          case CCSR:
            /* not going to implement clockrun stuff */
            regs.ccsr = reg;
            break;

          case TBICR:
            regs.tbicr = reg;
            if (reg & TBICR_MR_LOOPBACK)
                panic("TBICR_MR_LOOPBACK never used, something wrong!\n");

            if (reg & TBICR_MR_AN_ENABLE) {
                regs.tanlpar = regs.tanar;
                regs.tbisr |= (TBISR_MR_AN_COMPLETE | TBISR_MR_LINK_STATUS);
            }

#if 0
            if (reg & TBICR_MR_RESTART_AN) ;
#endif

            break;

          case TBISR:
            panic("TBISR is read only register!\n");

          case TANAR:
            regs.tanar = reg;
            if (reg & TANAR_PS2)
                panic("this isn't used in driver, something wrong!\n");

            if (reg & TANAR_PS1)
                panic("this isn't used in driver, something wrong!\n");
            break;

          case TANLPAR:
            panic("this should only be written to by the fake phy!\n");

          case TANER:
            panic("TANER is read only register!\n");

          case TESR:
            regs.tesr = reg;
            break;

          default:
            panic("invalid register access daddr=%#x", daddr);
        }
    } else {
        panic("Invalid Request Size");
    }

    return No_Fault;
}

void
NSGigE::devIntrPost(uint32_t interrupts)
{
    if (interrupts & ISR_RESERVE)
        panic("Cannot set a reserved interrupt");

    if (interrupts & ISR_NOIMPL)
        warn("interrupt not implemented %#x\n", interrupts);

    interrupts &= ~ISR_NOIMPL;
    regs.isr |= interrupts;

    if (interrupts & regs.imr) {
        if (interrupts & ISR_SWI) {
            totalSwi++;
        }
        if (interrupts & ISR_RXIDLE) {
            totalRxIdle++;
        }
        if (interrupts & ISR_RXOK) {
            totalRxOk++;
        }
        if (interrupts & ISR_RXDESC) {
            totalRxDesc++;
        }
        if (interrupts & ISR_TXOK) {
            totalTxOk++;
        }
        if (interrupts & ISR_TXIDLE) {
            totalTxIdle++;
        }
        if (interrupts & ISR_TXDESC) {
            totalTxDesc++;
        }
        if (interrupts & ISR_RXORN) {
            totalRxOrn++;
        }
    }

    DPRINTF(EthernetIntr,
            "interrupt written to ISR: intr=%#x isr=%#x imr=%#x\n",
            interrupts, regs.isr, regs.imr);

    if ((regs.isr & regs.imr)) {
        Tick when = curTick;
        if (!(regs.isr & regs.imr & ISR_NODELAY))
            when += intrDelay;
        cpuIntrPost(when);
    }
}

/* writing this interrupt counting stats inside this means that this function
   is now limited to being used to clear all interrupts upon the kernel
   reading isr and servicing.  just telling you in case you were thinking
   of expanding use.
*/
void
NSGigE::devIntrClear(uint32_t interrupts)
{
    if (interrupts & ISR_RESERVE)
        panic("Cannot clear a reserved interrupt");

    if (regs.isr & regs.imr & ISR_SWI) {
        postedSwi++;
    }
    if (regs.isr & regs.imr & ISR_RXIDLE) {
        postedRxIdle++;
    }
    if (regs.isr & regs.imr & ISR_RXOK) {
        postedRxOk++;
    }
    if (regs.isr & regs.imr & ISR_RXDESC) {
            postedRxDesc++;
    }
    if (regs.isr & regs.imr & ISR_TXOK) {
        postedTxOk++;
    }
    if (regs.isr & regs.imr & ISR_TXIDLE) {
        postedTxIdle++;
    }
    if (regs.isr & regs.imr & ISR_TXDESC) {
        postedTxDesc++;
    }
    if (regs.isr & regs.imr & ISR_RXORN) {
        postedRxOrn++;
    }

    if (regs.isr & regs.imr & (ISR_SWI | ISR_RXIDLE | ISR_RXOK | ISR_RXDESC |
                               ISR_TXOK | ISR_TXIDLE | ISR_TXDESC | ISR_RXORN) )
        postedInterrupts++;

    interrupts &= ~ISR_NOIMPL;
    regs.isr &= ~interrupts;

    DPRINTF(EthernetIntr,
            "interrupt cleared from ISR: intr=%x isr=%x imr=%x\n",
            interrupts, regs.isr, regs.imr);

    if (!(regs.isr & regs.imr))
        cpuIntrClear();
}

void
NSGigE::devIntrChangeMask()
{
    DPRINTF(EthernetIntr, "interrupt mask changed: isr=%x imr=%x masked=%x\n",
            regs.isr, regs.imr, regs.isr & regs.imr);

    if (regs.isr & regs.imr)
        cpuIntrPost(curTick);
    else
        cpuIntrClear();
}

void
NSGigE::cpuIntrPost(Tick when)
{
    // If the interrupt you want to post is later than an interrupt
    // already scheduled, just let it post in the coming one and don't
    // schedule another.
    // HOWEVER, must be sure that the scheduled intrTick is in the
    // future (this was formerly the source of a bug)
    /**
     * @todo this warning should be removed and the intrTick code should
     * be fixed.
     */
    assert(when >= curTick);
    assert(intrTick >= curTick || intrTick == 0);
    if (when > intrTick && intrTick != 0) {
        DPRINTF(EthernetIntr, "don't need to schedule event...intrTick=%d\n",
                intrTick);
        return;
    }

    intrTick = when;
    if (intrTick < curTick) {
        debug_break();
        intrTick = curTick;
    }

    DPRINTF(EthernetIntr, "going to schedule an interrupt for intrTick=%d\n",
            intrTick);

    if (intrEvent)
        intrEvent->squash();
    intrEvent = new IntrEvent(this, true);
    intrEvent->schedule(intrTick);
}

void
NSGigE::cpuInterrupt()
{
    assert(intrTick == curTick);

    // Whether or not there's a pending interrupt, we don't care about
    // it anymore
    intrEvent = 0;
    intrTick = 0;

    // Don't send an interrupt if there's already one
    if (cpuPendingIntr) {
        DPRINTF(EthernetIntr,
                "would send an interrupt now, but there's already pending\n");
    } else {
        // Send interrupt
        cpuPendingIntr = true;

        DPRINTF(EthernetIntr, "posting interrupt\n");
        intrPost();
    }
}

void
NSGigE::cpuIntrClear()
{
    if (!cpuPendingIntr)
        return;

    if (intrEvent) {
        intrEvent->squash();
        intrEvent = 0;
    }

    intrTick = 0;

    cpuPendingIntr = false;

    DPRINTF(EthernetIntr, "clearing interrupt\n");
    intrClear();
}

bool
NSGigE::cpuIntrPending() const
{ return cpuPendingIntr; }

void
NSGigE::txReset()
{

    DPRINTF(Ethernet, "transmit reset\n");

    CTDD = false;
    txEnable = false;;
    txFragPtr = 0;
    assert(txDescCnt == 0);
    txFifo.clear();
    txState = txIdle;
    assert(txDmaState == dmaIdle);
}

void
NSGigE::rxReset()
{
    DPRINTF(Ethernet, "receive reset\n");

    CRDD = false;
    assert(rxPktBytes == 0);
    rxEnable = false;
    rxFragPtr = 0;
    assert(rxDescCnt == 0);
    assert(rxDmaState == dmaIdle);
    rxFifo.clear();
    rxState = rxIdle;
}

void
NSGigE::regsReset()
{
    memset(&regs, 0, sizeof(regs));
    regs.config = CFGR_LNKSTS;
    regs.mear = 0x22;
    regs.txcfg = 0x120; // set drain threshold to 1024 bytes and
                        // fill threshold to 32 bytes
    regs.rxcfg = 0x4;   // set drain threshold to 16 bytes
    regs.srr = 0x0103;  // set the silicon revision to rev B or 0x103
    regs.mibc = MIBC_FRZ;
    regs.vdr = 0x81;    // set the vlan tag type to 802.1q
    regs.tesr = 0xc000; // TBI capable of both full and half duplex

    extstsEnable = false;
    acceptBroadcast = false;
    acceptMulticast = false;
    acceptUnicast = false;
    acceptPerfect = false;
    acceptArp = false;
}

void
NSGigE::rxDmaReadCopy()
{
    assert(rxDmaState == dmaReading);

    physmem->dma_read((uint8_t *)rxDmaData, rxDmaAddr, rxDmaLen);
    rxDmaState = dmaIdle;

    DPRINTF(EthernetDMA, "rx dma read  paddr=%#x len=%d\n",
            rxDmaAddr, rxDmaLen);
    DDUMP(EthernetDMA, rxDmaData, rxDmaLen);
}

bool
NSGigE::doRxDmaRead()
{
    assert(rxDmaState == dmaIdle || rxDmaState == dmaReadWaiting);
    rxDmaState = dmaReading;

    if (dmaInterface && !rxDmaFree) {
        if (dmaInterface->busy())
            rxDmaState = dmaReadWaiting;
        else
            dmaInterface->doDMA(Read, rxDmaAddr, rxDmaLen, curTick,
                                &rxDmaReadEvent, true);
        return true;
    }

    if (dmaReadDelay == 0 && dmaReadFactor == 0) {
        rxDmaReadCopy();
        return false;
    }

    Tick factor = ((rxDmaLen + ULL(63)) >> ULL(6)) * dmaReadFactor;
    Tick start = curTick + dmaReadDelay + factor;
    rxDmaReadEvent.schedule(start);
    return true;
}

void
NSGigE::rxDmaReadDone()
{
    assert(rxDmaState == dmaReading);
    rxDmaReadCopy();

    // If the transmit state machine has a pending DMA, let it go first
    if (txDmaState == dmaReadWaiting || txDmaState == dmaWriteWaiting)
        txKick();

    rxKick();
}

void
NSGigE::rxDmaWriteCopy()
{
    assert(rxDmaState == dmaWriting);

    physmem->dma_write(rxDmaAddr, (uint8_t *)rxDmaData, rxDmaLen);
    rxDmaState = dmaIdle;

    DPRINTF(EthernetDMA, "rx dma write paddr=%#x len=%d\n",
            rxDmaAddr, rxDmaLen);
    DDUMP(EthernetDMA, rxDmaData, rxDmaLen);
}

bool
NSGigE::doRxDmaWrite()
{
    assert(rxDmaState == dmaIdle || rxDmaState == dmaWriteWaiting);
    rxDmaState = dmaWriting;

    if (dmaInterface && !rxDmaFree) {
        if (dmaInterface->busy())
            rxDmaState = dmaWriteWaiting;
        else
            dmaInterface->doDMA(WriteInvalidate, rxDmaAddr, rxDmaLen, curTick,
                                &rxDmaWriteEvent, true);
        return true;
    }

    if (dmaWriteDelay == 0 && dmaWriteFactor == 0) {
        rxDmaWriteCopy();
        return false;
    }

    Tick factor = ((rxDmaLen + ULL(63)) >> ULL(6)) * dmaWriteFactor;
    Tick start = curTick + dmaWriteDelay + factor;
    rxDmaWriteEvent.schedule(start);
    return true;
}

void
NSGigE::rxDmaWriteDone()
{
    assert(rxDmaState == dmaWriting);
    rxDmaWriteCopy();

    // If the transmit state machine has a pending DMA, let it go first
    if (txDmaState == dmaReadWaiting || txDmaState == dmaWriteWaiting)
        txKick();

    rxKick();
}

void
NSGigE::rxKick()
{
    DPRINTF(EthernetSM, "receive kick rxState=%s (rxBuf.size=%d)\n",
            NsRxStateStrings[rxState], rxFifo.size());

    if (rxKickTick > curTick) {
        DPRINTF(EthernetSM, "receive kick exiting, can't run till %d\n",
                rxKickTick);
        return;
    }

  next:
    switch(rxDmaState) {
      case dmaReadWaiting:
        if (doRxDmaRead())
            goto exit;
        break;
      case dmaWriteWaiting:
        if (doRxDmaWrite())
            goto exit;
        break;
      default:
        break;
    }

    // see state machine from spec for details
    // the way this works is, if you finish work on one state and can
    // go directly to another, you do that through jumping to the
    // label "next".  however, if you have intermediate work, like DMA
    // so that you can't go to the next state yet, you go to exit and
    // exit the loop.  however, when the DMA is done it will trigger
    // an event and come back to this loop.
    switch (rxState) {
      case rxIdle:
        if (!rxEnable) {
            DPRINTF(EthernetSM, "Receive Disabled! Nothing to do.\n");
            goto exit;
        }

        if (CRDD) {
            rxState = rxDescRefr;

            rxDmaAddr = regs.rxdp & 0x3fffffff;
            rxDmaData = &rxDescCache + offsetof(ns_desc, link);
            rxDmaLen = sizeof(rxDescCache.link);
            rxDmaFree = dmaDescFree;

            descDmaReads++;
            descDmaRdBytes += rxDmaLen;

            if (doRxDmaRead())
                goto exit;
        } else {
            rxState = rxDescRead;

            rxDmaAddr = regs.rxdp & 0x3fffffff;
            rxDmaData = &rxDescCache;
            rxDmaLen = sizeof(ns_desc);
            rxDmaFree = dmaDescFree;

            descDmaReads++;
            descDmaRdBytes += rxDmaLen;

            if (doRxDmaRead())
                goto exit;
        }
        break;

      case rxDescRefr:
        if (rxDmaState != dmaIdle)
            goto exit;

        rxState = rxAdvance;
        break;

     case rxDescRead:
        if (rxDmaState != dmaIdle)
            goto exit;

        DPRINTF(EthernetDesc,
                "rxDescCache: addr=%08x read descriptor\n",
                regs.rxdp & 0x3fffffff);
        DPRINTF(EthernetDesc,
                "rxDescCache: link=%08x bufptr=%08x cmdsts=%08x extsts=%08x\n",
                rxDescCache.link, rxDescCache.bufptr, rxDescCache.cmdsts,
                rxDescCache.extsts);

        if (rxDescCache.cmdsts & CMDSTS_OWN) {
            devIntrPost(ISR_RXIDLE);
            rxState = rxIdle;
            goto exit;
        } else {
            rxState = rxFifoBlock;
            rxFragPtr = rxDescCache.bufptr;
            rxDescCnt = rxDescCache.cmdsts & CMDSTS_LEN_MASK;
        }
        break;

      case rxFifoBlock:
        if (!rxPacket) {
            /**
             * @todo in reality, we should be able to start processing
             * the packet as it arrives, and not have to wait for the
             * full packet ot be in the receive fifo.
             */
            if (rxFifo.empty())
                goto exit;

            DPRINTF(EthernetSM, "****processing receive of new packet****\n");

            // If we don't have a packet, grab a new one from the fifo.
            rxPacket = rxFifo.front();
            rxPktBytes = rxPacket->length;
            rxPacketBufPtr = rxPacket->data;

#if TRACING_ON
            if (DTRACE(Ethernet)) {
                IpPtr ip(rxPacket);
                if (ip) {
                    DPRINTF(Ethernet, "ID is %d\n", ip->id());
                    TcpPtr tcp(ip);
                    if (tcp) {
                        DPRINTF(Ethernet,
                                "Src Port=%d, Dest Port=%d, Seq=%d, Ack=%d\n",
                                tcp->sport(), tcp->dport(), tcp->seq(),
                                tcp->ack());
                    }
                }
            }
#endif

            // sanity check - i think the driver behaves like this
            assert(rxDescCnt >= rxPktBytes);
            rxFifo.pop();
        }


        // dont' need the && rxDescCnt > 0 if driver sanity check
        // above holds
        if (rxPktBytes > 0) {
            rxState = rxFragWrite;
            // don't need min<>(rxPktBytes,rxDescCnt) if above sanity
            // check holds
            rxXferLen = rxPktBytes;

            rxDmaAddr = rxFragPtr & 0x3fffffff;
            rxDmaData = rxPacketBufPtr;
            rxDmaLen = rxXferLen;
            rxDmaFree = dmaDataFree;

            if (doRxDmaWrite())
                goto exit;

        } else {
            rxState = rxDescWrite;

            //if (rxPktBytes == 0) {  /* packet is done */
            assert(rxPktBytes == 0);
            DPRINTF(EthernetSM, "done with receiving packet\n");

            rxDescCache.cmdsts |= CMDSTS_OWN;
            rxDescCache.cmdsts &= ~CMDSTS_MORE;
            rxDescCache.cmdsts |= CMDSTS_OK;
            rxDescCache.cmdsts &= 0xffff0000;
            rxDescCache.cmdsts += rxPacket->length;   //i.e. set CMDSTS_SIZE

#if 0
            /*
             * all the driver uses these are for its own stats keeping
             * which we don't care about, aren't necessary for
             * functionality and doing this would just slow us down.
             * if they end up using this in a later version for
             * functional purposes, just undef
             */
            if (rxFilterEnable) {
                rxDescCache.cmdsts &= ~CMDSTS_DEST_MASK;
                const EthAddr &dst = rxFifoFront()->dst();
                if (dst->unicast())
                    rxDescCache.cmdsts |= CMDSTS_DEST_SELF;
                if (dst->multicast())
                    rxDescCache.cmdsts |= CMDSTS_DEST_MULTI;
                if (dst->broadcast())
                    rxDescCache.cmdsts |= CMDSTS_DEST_MASK;
            }
#endif

            IpPtr ip(rxPacket);
            if (extstsEnable && ip) {
                rxDescCache.extsts |= EXTSTS_IPPKT;
                rxIpChecksums++;
                if (cksum(ip) != 0) {
                    DPRINTF(EthernetCksum, "Rx IP Checksum Error\n");
                    rxDescCache.extsts |= EXTSTS_IPERR;
                }
                TcpPtr tcp(ip);
                UdpPtr udp(ip);
                if (tcp) {
                    rxDescCache.extsts |= EXTSTS_TCPPKT;
                    rxTcpChecksums++;
                    if (cksum(tcp) != 0) {
                        DPRINTF(EthernetCksum, "Rx TCP Checksum Error\n");
                        rxDescCache.extsts |= EXTSTS_TCPERR;

                    }
                } else if (udp) {
                    rxDescCache.extsts |= EXTSTS_UDPPKT;
                    rxUdpChecksums++;
                    if (cksum(udp) != 0) {
                        DPRINTF(EthernetCksum, "Rx UDP Checksum Error\n");
                        rxDescCache.extsts |= EXTSTS_UDPERR;
                    }
                }
            }
            rxPacket = 0;

            /*
             * the driver seems to always receive into desc buffers
             * of size 1514, so you never have a pkt that is split
             * into multiple descriptors on the receive side, so
             * i don't implement that case, hence the assert above.
             */

            DPRINTF(EthernetDesc,
                    "rxDescCache: addr=%08x writeback cmdsts extsts\n",
                    regs.rxdp & 0x3fffffff);
            DPRINTF(EthernetDesc,
                    "rxDescCache: link=%08x bufptr=%08x cmdsts=%08x extsts=%08x\n",
                    rxDescCache.link, rxDescCache.bufptr, rxDescCache.cmdsts,
                    rxDescCache.extsts);

            rxDmaAddr = (regs.rxdp + offsetof(ns_desc, cmdsts)) & 0x3fffffff;
            rxDmaData = &(rxDescCache.cmdsts);
            rxDmaLen = sizeof(rxDescCache.cmdsts) + sizeof(rxDescCache.extsts);
            rxDmaFree = dmaDescFree;

            descDmaWrites++;
            descDmaWrBytes += rxDmaLen;

            if (doRxDmaWrite())
                goto exit;
        }
        break;

      case rxFragWrite:
        if (rxDmaState != dmaIdle)
            goto exit;

        rxPacketBufPtr += rxXferLen;
        rxFragPtr += rxXferLen;
        rxPktBytes -= rxXferLen;

        rxState = rxFifoBlock;
        break;

      case rxDescWrite:
        if (rxDmaState != dmaIdle)
            goto exit;

        assert(rxDescCache.cmdsts & CMDSTS_OWN);

        assert(rxPacket == 0);
        devIntrPost(ISR_RXOK);

        if (rxDescCache.cmdsts & CMDSTS_INTR)
            devIntrPost(ISR_RXDESC);

        if (!rxEnable) {
            DPRINTF(EthernetSM, "Halting the RX state machine\n");
            rxState = rxIdle;
            goto exit;
        } else
            rxState = rxAdvance;
        break;

      case rxAdvance:
        if (rxDescCache.link == 0) {
            devIntrPost(ISR_RXIDLE);
            rxState = rxIdle;
            CRDD = true;
            goto exit;
        } else {
            rxState = rxDescRead;
            regs.rxdp = rxDescCache.link;
            CRDD = false;

            rxDmaAddr = regs.rxdp & 0x3fffffff;
            rxDmaData = &rxDescCache;
            rxDmaLen = sizeof(ns_desc);
            rxDmaFree = dmaDescFree;

            if (doRxDmaRead())
                goto exit;
        }
        break;

      default:
        panic("Invalid rxState!");
    }

    DPRINTF(EthernetSM, "entering next rxState=%s\n",
            NsRxStateStrings[rxState]);

    goto next;

  exit:
    /**
     * @todo do we want to schedule a future kick?
     */
    DPRINTF(EthernetSM, "rx state machine exited rxState=%s\n",
            NsRxStateStrings[rxState]);
}

void
NSGigE::transmit()
{
    if (txFifo.empty()) {
        DPRINTF(Ethernet, "nothing to transmit\n");
        return;
    }

    DPRINTF(Ethernet, "Attempt Pkt Transmit: txFifo length=%d\n",
            txFifo.size());
    if (interface->sendPacket(txFifo.front())) {
#if TRACING_ON
        if (DTRACE(Ethernet)) {
            IpPtr ip(txFifo.front());
            if (ip) {
                DPRINTF(Ethernet, "ID is %d\n", ip->id());
                TcpPtr tcp(ip);
                if (tcp) {
                    DPRINTF(Ethernet,
                            "Src Port=%d, Dest Port=%d, Seq=%d, Ack=%d\n",
                            tcp->sport(), tcp->dport(), tcp->seq(), tcp->ack());
                }
            }
        }
#endif

        DDUMP(EthernetData, txFifo.front()->data, txFifo.front()->length);
        txBytes += txFifo.front()->length;
        txPackets++;

        DPRINTF(Ethernet, "Successful Xmit! now txFifoAvail is %d\n",
                txFifo.avail());
        txFifo.pop();

        /*
         * normally do a writeback of the descriptor here, and ONLY
         * after that is done, send this interrupt.  but since our
         * stuff never actually fails, just do this interrupt here,
         * otherwise the code has to stray from this nice format.
         * besides, it's functionally the same.
         */
        devIntrPost(ISR_TXOK);
    }

   if (!txFifo.empty() && !txEvent.scheduled()) {
       DPRINTF(Ethernet, "reschedule transmit\n");
       txEvent.schedule(curTick + retryTime);
   }
}

void
NSGigE::txDmaReadCopy()
{
    assert(txDmaState == dmaReading);

    physmem->dma_read((uint8_t *)txDmaData, txDmaAddr, txDmaLen);
    txDmaState = dmaIdle;

    DPRINTF(EthernetDMA, "tx dma read  paddr=%#x len=%d\n",
            txDmaAddr, txDmaLen);
    DDUMP(EthernetDMA, txDmaData, txDmaLen);
}

bool
NSGigE::doTxDmaRead()
{
    assert(txDmaState == dmaIdle || txDmaState == dmaReadWaiting);
    txDmaState = dmaReading;

    if (dmaInterface && !txDmaFree) {
        if (dmaInterface->busy())
            txDmaState = dmaReadWaiting;
        else
            dmaInterface->doDMA(Read, txDmaAddr, txDmaLen, curTick,
                                &txDmaReadEvent, true);
        return true;
    }

    if (dmaReadDelay == 0 && dmaReadFactor == 0.0) {
        txDmaReadCopy();
        return false;
    }

    Tick factor = ((txDmaLen + ULL(63)) >> ULL(6)) * dmaReadFactor;
    Tick start = curTick + dmaReadDelay + factor;
    txDmaReadEvent.schedule(start);
    return true;
}

void
NSGigE::txDmaReadDone()
{
    assert(txDmaState == dmaReading);
    txDmaReadCopy();

    // If the receive state machine  has a pending DMA, let it go first
    if (rxDmaState == dmaReadWaiting || rxDmaState == dmaWriteWaiting)
        rxKick();

    txKick();
}

void
NSGigE::txDmaWriteCopy()
{
    assert(txDmaState == dmaWriting);

    physmem->dma_write(txDmaAddr, (uint8_t *)txDmaData, txDmaLen);
    txDmaState = dmaIdle;

    DPRINTF(EthernetDMA, "tx dma write paddr=%#x len=%d\n",
            txDmaAddr, txDmaLen);
    DDUMP(EthernetDMA, txDmaData, txDmaLen);
}

bool
NSGigE::doTxDmaWrite()
{
    assert(txDmaState == dmaIdle || txDmaState == dmaWriteWaiting);
    txDmaState = dmaWriting;

    if (dmaInterface && !txDmaFree) {
        if (dmaInterface->busy())
            txDmaState = dmaWriteWaiting;
        else
            dmaInterface->doDMA(WriteInvalidate, txDmaAddr, txDmaLen, curTick,
                                &txDmaWriteEvent, true);
        return true;
    }

    if (dmaWriteDelay == 0 && dmaWriteFactor == 0.0) {
        txDmaWriteCopy();
        return false;
    }

    Tick factor = ((txDmaLen + ULL(63)) >> ULL(6)) * dmaWriteFactor;
    Tick start = curTick + dmaWriteDelay + factor;
    txDmaWriteEvent.schedule(start);
    return true;
}

void
NSGigE::txDmaWriteDone()
{
    assert(txDmaState == dmaWriting);
    txDmaWriteCopy();

    // If the receive state machine  has a pending DMA, let it go first
    if (rxDmaState == dmaReadWaiting || rxDmaState == dmaWriteWaiting)
        rxKick();

    txKick();
}

void
NSGigE::txKick()
{
    DPRINTF(EthernetSM, "transmit kick txState=%s\n",
            NsTxStateStrings[txState]);

    if (txKickTick > curTick) {
        DPRINTF(EthernetSM, "transmit kick exiting, can't run till %d\n",
                txKickTick);
        return;
    }

  next:
    switch(txDmaState) {
      case dmaReadWaiting:
        if (doTxDmaRead())
            goto exit;
        break;
      case dmaWriteWaiting:
        if (doTxDmaWrite())
            goto exit;
        break;
      default:
        break;
    }

    switch (txState) {
      case txIdle:
        if (!txEnable) {
            DPRINTF(EthernetSM, "Transmit disabled.  Nothing to do.\n");
            goto exit;
        }

        if (CTDD) {
            txState = txDescRefr;

            txDmaAddr = regs.txdp & 0x3fffffff;
            txDmaData = &txDescCache + offsetof(ns_desc, link);
            txDmaLen = sizeof(txDescCache.link);
            txDmaFree = dmaDescFree;

            descDmaReads++;
            descDmaRdBytes += txDmaLen;

            if (doTxDmaRead())
                goto exit;

        } else {
            txState = txDescRead;

            txDmaAddr = regs.txdp & 0x3fffffff;
            txDmaData = &txDescCache;
            txDmaLen = sizeof(ns_desc);
            txDmaFree = dmaDescFree;

            descDmaReads++;
            descDmaRdBytes += txDmaLen;

            if (doTxDmaRead())
                goto exit;
        }
        break;

      case txDescRefr:
        if (txDmaState != dmaIdle)
            goto exit;

        txState = txAdvance;
        break;

      case txDescRead:
        if (txDmaState != dmaIdle)
            goto exit;

        DPRINTF(EthernetDesc,
                "txDescCache: link=%08x bufptr=%08x cmdsts=%08x extsts=%08x\n",
                txDescCache.link, txDescCache.bufptr, txDescCache.cmdsts,
                txDescCache.extsts);

        if (txDescCache.cmdsts & CMDSTS_OWN) {
            txState = txFifoBlock;
            txFragPtr = txDescCache.bufptr;
            txDescCnt = txDescCache.cmdsts & CMDSTS_LEN_MASK;
        } else {
            devIntrPost(ISR_TXIDLE);
            txState = txIdle;
            goto exit;
        }
        break;

      case txFifoBlock:
        if (!txPacket) {
            DPRINTF(EthernetSM, "****starting the tx of a new packet****\n");
            txPacket = new PacketData(16384);
            txPacketBufPtr = txPacket->data;
        }

        if (txDescCnt == 0) {
            DPRINTF(EthernetSM, "the txDescCnt == 0, done with descriptor\n");
            if (txDescCache.cmdsts & CMDSTS_MORE) {
                DPRINTF(EthernetSM, "there are more descriptors to come\n");
                txState = txDescWrite;

                txDescCache.cmdsts &= ~CMDSTS_OWN;

                txDmaAddr = regs.txdp + offsetof(ns_desc, cmdsts);
                txDmaAddr &= 0x3fffffff;
                txDmaData = &(txDescCache.cmdsts);
                txDmaLen = sizeof(txDescCache.cmdsts);
                txDmaFree = dmaDescFree;

                if (doTxDmaWrite())
                    goto exit;

            } else { /* this packet is totally done */
                DPRINTF(EthernetSM, "This packet is done, let's wrap it up\n");
                /* deal with the the packet that just finished */
                if ((regs.vtcr & VTCR_PPCHK) && extstsEnable) {
                    IpPtr ip(txPacket);
                    if (txDescCache.extsts & EXTSTS_UDPPKT) {
                        UdpPtr udp(ip);
                        udp->sum(0);
                        udp->sum(cksum(udp));
                        txUdpChecksums++;
                    } else if (txDescCache.extsts & EXTSTS_TCPPKT) {
                        TcpPtr tcp(ip);
                        tcp->sum(0);
                        tcp->sum(cksum(tcp));
                        txTcpChecksums++;
                    }
                    if (txDescCache.extsts & EXTSTS_IPPKT) {
                        ip->sum(0);
                        ip->sum(cksum(ip));
                        txIpChecksums++;
                    }
                }

                txPacket->length = txPacketBufPtr - txPacket->data;
                // this is just because the receive can't handle a
                // packet bigger want to make sure
                assert(txPacket->length <= 1514);
#ifndef NDEBUG
                bool success =
#endif
                    txFifo.push(txPacket);
                assert(success);

                /*
                 * this following section is not tqo spec, but
                 * functionally shouldn't be any different.  normally,
                 * the chip will wait til the transmit has occurred
                 * before writing back the descriptor because it has
                 * to wait to see that it was successfully transmitted
                 * to decide whether to set CMDSTS_OK or not.
                 * however, in the simulator since it is always
                 * successfully transmitted, and writing it exactly to
                 * spec would complicate the code, we just do it here
                 */

                txDescCache.cmdsts &= ~CMDSTS_OWN;
                txDescCache.cmdsts |= CMDSTS_OK;

                DPRINTF(EthernetDesc,
                        "txDesc writeback: cmdsts=%08x extsts=%08x\n",
                        txDescCache.cmdsts, txDescCache.extsts);

                txDmaAddr = regs.txdp + offsetof(ns_desc, cmdsts);
                txDmaAddr &= 0x3fffffff;
                txDmaData = &(txDescCache.cmdsts);
                txDmaLen = sizeof(txDescCache.cmdsts) +
                    sizeof(txDescCache.extsts);
                txDmaFree = dmaDescFree;

                descDmaWrites++;
                descDmaWrBytes += txDmaLen;

                transmit();
                txPacket = 0;

                if (!txEnable) {
                    DPRINTF(EthernetSM, "halting TX state machine\n");
                    txState = txIdle;
                    goto exit;
                } else
                    txState = txAdvance;

                if (doTxDmaWrite())
                    goto exit;
            }
        } else {
            DPRINTF(EthernetSM, "this descriptor isn't done yet\n");
            if (!txFifo.full()) {
                txState = txFragRead;

                /*
                 * The number of bytes transferred is either whatever
                 * is left in the descriptor (txDescCnt), or if there
                 * is not enough room in the fifo, just whatever room
                 * is left in the fifo
                 */
                txXferLen = min<uint32_t>(txDescCnt, txFifo.avail());

                txDmaAddr = txFragPtr & 0x3fffffff;
                txDmaData = txPacketBufPtr;
                txDmaLen = txXferLen;
                txDmaFree = dmaDataFree;

                if (doTxDmaRead())
                    goto exit;
            } else {
                txState = txFifoBlock;
                transmit();

                goto exit;
            }

        }
        break;

      case txFragRead:
        if (txDmaState != dmaIdle)
            goto exit;

        txPacketBufPtr += txXferLen;
        txFragPtr += txXferLen;
        txDescCnt -= txXferLen;
        txFifo.reserve(txXferLen);

        txState = txFifoBlock;
        break;

      case txDescWrite:
        if (txDmaState != dmaIdle)
            goto exit;

        if (txDescCache.cmdsts & CMDSTS_INTR)
            devIntrPost(ISR_TXDESC);

        txState = txAdvance;
        break;

      case txAdvance:
        if (txDescCache.link == 0) {
            devIntrPost(ISR_TXIDLE);
            txState = txIdle;
            goto exit;
        } else {
            txState = txDescRead;
            regs.txdp = txDescCache.link;
            CTDD = false;

            txDmaAddr = txDescCache.link & 0x3fffffff;
            txDmaData = &txDescCache;
            txDmaLen = sizeof(ns_desc);
            txDmaFree = dmaDescFree;

            if (doTxDmaRead())
                goto exit;
        }
        break;

      default:
        panic("invalid state");
    }

    DPRINTF(EthernetSM, "entering next txState=%s\n",
            NsTxStateStrings[txState]);

    goto next;

  exit:
    /**
     * @todo do we want to schedule a future kick?
     */
    DPRINTF(EthernetSM, "tx state machine exited txState=%s\n",
            NsTxStateStrings[txState]);
}

void
NSGigE::transferDone()
{
    if (txFifo.empty()) {
        DPRINTF(Ethernet, "transfer complete: txFifo empty...nothing to do\n");
        return;
    }

    DPRINTF(Ethernet, "transfer complete: data in txFifo...schedule xmit\n");

    if (txEvent.scheduled())
        txEvent.reschedule(curTick + cycles(1));
    else
        txEvent.schedule(curTick + cycles(1));
}

bool
NSGigE::rxFilter(const PacketPtr &packet)
{
    EthPtr eth = packet;
    bool drop = true;
    string type;

    const EthAddr &dst = eth->dst();
    if (dst.unicast()) {
        // If we're accepting all unicast addresses
        if (acceptUnicast)
            drop = false;

        // If we make a perfect match
        if (acceptPerfect && dst == rom.perfectMatch)
            drop = false;

        if (acceptArp && eth->type() == ETH_TYPE_ARP)
            drop = false;

    } else if (dst.broadcast()) {
        // if we're accepting broadcasts
        if (acceptBroadcast)
            drop = false;

    } else if (dst.multicast()) {
        // if we're accepting all multicasts
        if (acceptMulticast)
            drop = false;

    }

    if (drop) {
        DPRINTF(Ethernet, "rxFilter drop\n");
        DDUMP(EthernetData, packet->data, packet->length);
    }

    return drop;
}

bool
NSGigE::recvPacket(PacketPtr packet)
{
    rxBytes += packet->length;
    rxPackets++;

    DPRINTF(Ethernet, "Receiving packet from wire, rxFifoAvail=%d\n",
            rxFifo.avail());

    if (!rxEnable) {
        DPRINTF(Ethernet, "receive disabled...packet dropped\n");
        interface->recvDone();
        return true;
    }

    if (rxFilterEnable && rxFilter(packet)) {
        DPRINTF(Ethernet, "packet filtered...dropped\n");
        interface->recvDone();
        return true;
    }

    if (rxFifo.avail() < packet->length) {
#if TRACING_ON
        IpPtr ip(packet);
        TcpPtr tcp(ip);
        if (ip) {
            DPRINTF(Ethernet,
                    "packet won't fit in receive buffer...pkt ID %d dropped\n",
                    ip->id());
            if (tcp) {
                DPRINTF(Ethernet, "Seq=%d\n", tcp->seq());
            }
        }
#endif
        droppedPackets++;
        devIntrPost(ISR_RXORN);
        return false;
    }

    rxFifo.push(packet);
    interface->recvDone();

    rxKick();
    return true;
}

//=====================================================================
//
//
void
NSGigE::serialize(ostream &os)
{
    // Serialize the PciDev base class
    PciDev::serialize(os);

    /*
     * Finalize any DMA events now.
     */
    if (rxDmaReadEvent.scheduled())
        rxDmaReadCopy();
    if (rxDmaWriteEvent.scheduled())
        rxDmaWriteCopy();
    if (txDmaReadEvent.scheduled())
        txDmaReadCopy();
    if (txDmaWriteEvent.scheduled())
        txDmaWriteCopy();

    /*
     * Serialize the device registers
     */
    SERIALIZE_SCALAR(regs.command);
    SERIALIZE_SCALAR(regs.config);
    SERIALIZE_SCALAR(regs.mear);
    SERIALIZE_SCALAR(regs.ptscr);
    SERIALIZE_SCALAR(regs.isr);
    SERIALIZE_SCALAR(regs.imr);
    SERIALIZE_SCALAR(regs.ier);
    SERIALIZE_SCALAR(regs.ihr);
    SERIALIZE_SCALAR(regs.txdp);
    SERIALIZE_SCALAR(regs.txdp_hi);
    SERIALIZE_SCALAR(regs.txcfg);
    SERIALIZE_SCALAR(regs.gpior);
    SERIALIZE_SCALAR(regs.rxdp);
    SERIALIZE_SCALAR(regs.rxdp_hi);
    SERIALIZE_SCALAR(regs.rxcfg);
    SERIALIZE_SCALAR(regs.pqcr);
    SERIALIZE_SCALAR(regs.wcsr);
    SERIALIZE_SCALAR(regs.pcr);
    SERIALIZE_SCALAR(regs.rfcr);
    SERIALIZE_SCALAR(regs.rfdr);
    SERIALIZE_SCALAR(regs.srr);
    SERIALIZE_SCALAR(regs.mibc);
    SERIALIZE_SCALAR(regs.vrcr);
    SERIALIZE_SCALAR(regs.vtcr);
    SERIALIZE_SCALAR(regs.vdr);
    SERIALIZE_SCALAR(regs.ccsr);
    SERIALIZE_SCALAR(regs.tbicr);
    SERIALIZE_SCALAR(regs.tbisr);
    SERIALIZE_SCALAR(regs.tanar);
    SERIALIZE_SCALAR(regs.tanlpar);
    SERIALIZE_SCALAR(regs.taner);
    SERIALIZE_SCALAR(regs.tesr);

    SERIALIZE_ARRAY(rom.perfectMatch, ETH_ADDR_LEN);

    SERIALIZE_SCALAR(ioEnable);

    /*
     * Serialize the data Fifos
     */
    rxFifo.serialize("rxFifo", os);
    txFifo.serialize("txFifo", os);

    /*
     * Serialize the various helper variables
     */
    bool txPacketExists = txPacket;
    SERIALIZE_SCALAR(txPacketExists);
    if (txPacketExists) {
        txPacket->length = txPacketBufPtr - txPacket->data;
        txPacket->serialize("txPacket", os);
        uint32_t txPktBufPtr = (uint32_t) (txPacketBufPtr - txPacket->data);
        SERIALIZE_SCALAR(txPktBufPtr);
    }

    bool rxPacketExists = rxPacket;
    SERIALIZE_SCALAR(rxPacketExists);
    if (rxPacketExists) {
        rxPacket->serialize("rxPacket", os);
        uint32_t rxPktBufPtr = (uint32_t) (rxPacketBufPtr - rxPacket->data);
        SERIALIZE_SCALAR(rxPktBufPtr);
    }

    SERIALIZE_SCALAR(txXferLen);
    SERIALIZE_SCALAR(rxXferLen);

    /*
     * Serialize DescCaches
     */
    SERIALIZE_SCALAR(txDescCache.link);
    SERIALIZE_SCALAR(txDescCache.bufptr);
    SERIALIZE_SCALAR(txDescCache.cmdsts);
    SERIALIZE_SCALAR(txDescCache.extsts);
    SERIALIZE_SCALAR(rxDescCache.link);
    SERIALIZE_SCALAR(rxDescCache.bufptr);
    SERIALIZE_SCALAR(rxDescCache.cmdsts);
    SERIALIZE_SCALAR(rxDescCache.extsts);

    /*
     * Serialize tx state machine
     */
    int txState = this->txState;
    SERIALIZE_SCALAR(txState);
    SERIALIZE_SCALAR(txEnable);
    SERIALIZE_SCALAR(CTDD);
    SERIALIZE_SCALAR(txFragPtr);
    SERIALIZE_SCALAR(txDescCnt);
    int txDmaState = this->txDmaState;
    SERIALIZE_SCALAR(txDmaState);

    /*
     * Serialize rx state machine
     */
    int rxState = this->rxState;
    SERIALIZE_SCALAR(rxState);
    SERIALIZE_SCALAR(rxEnable);
    SERIALIZE_SCALAR(CRDD);
    SERIALIZE_SCALAR(rxPktBytes);
    SERIALIZE_SCALAR(rxFragPtr);
    SERIALIZE_SCALAR(rxDescCnt);
    int rxDmaState = this->rxDmaState;
    SERIALIZE_SCALAR(rxDmaState);

    SERIALIZE_SCALAR(extstsEnable);

    /*
     * If there's a pending transmit, store the time so we can
     * reschedule it later
     */
    Tick transmitTick = txEvent.scheduled() ? txEvent.when() - curTick : 0;
    SERIALIZE_SCALAR(transmitTick);

    /*
     * receive address filter settings
     */
    SERIALIZE_SCALAR(rxFilterEnable);
    SERIALIZE_SCALAR(acceptBroadcast);
    SERIALIZE_SCALAR(acceptMulticast);
    SERIALIZE_SCALAR(acceptUnicast);
    SERIALIZE_SCALAR(acceptPerfect);
    SERIALIZE_SCALAR(acceptArp);

    /*
     * Keep track of pending interrupt status.
     */
    SERIALIZE_SCALAR(intrTick);
    SERIALIZE_SCALAR(cpuPendingIntr);
    Tick intrEventTick = 0;
    if (intrEvent)
        intrEventTick = intrEvent->when();
    SERIALIZE_SCALAR(intrEventTick);

}

void
NSGigE::unserialize(Checkpoint *cp, const std::string &section)
{
    // Unserialize the PciDev base class
    PciDev::unserialize(cp, section);

    UNSERIALIZE_SCALAR(regs.command);
    UNSERIALIZE_SCALAR(regs.config);
    UNSERIALIZE_SCALAR(regs.mear);
    UNSERIALIZE_SCALAR(regs.ptscr);
    UNSERIALIZE_SCALAR(regs.isr);
    UNSERIALIZE_SCALAR(regs.imr);
    UNSERIALIZE_SCALAR(regs.ier);
    UNSERIALIZE_SCALAR(regs.ihr);
    UNSERIALIZE_SCALAR(regs.txdp);
    UNSERIALIZE_SCALAR(regs.txdp_hi);
    UNSERIALIZE_SCALAR(regs.txcfg);
    UNSERIALIZE_SCALAR(regs.gpior);
    UNSERIALIZE_SCALAR(regs.rxdp);
    UNSERIALIZE_SCALAR(regs.rxdp_hi);
    UNSERIALIZE_SCALAR(regs.rxcfg);
    UNSERIALIZE_SCALAR(regs.pqcr);
    UNSERIALIZE_SCALAR(regs.wcsr);
    UNSERIALIZE_SCALAR(regs.pcr);
    UNSERIALIZE_SCALAR(regs.rfcr);
    UNSERIALIZE_SCALAR(regs.rfdr);
    UNSERIALIZE_SCALAR(regs.srr);
    UNSERIALIZE_SCALAR(regs.mibc);
    UNSERIALIZE_SCALAR(regs.vrcr);
    UNSERIALIZE_SCALAR(regs.vtcr);
    UNSERIALIZE_SCALAR(regs.vdr);
    UNSERIALIZE_SCALAR(regs.ccsr);
    UNSERIALIZE_SCALAR(regs.tbicr);
    UNSERIALIZE_SCALAR(regs.tbisr);
    UNSERIALIZE_SCALAR(regs.tanar);
    UNSERIALIZE_SCALAR(regs.tanlpar);
    UNSERIALIZE_SCALAR(regs.taner);
    UNSERIALIZE_SCALAR(regs.tesr);

    UNSERIALIZE_ARRAY(rom.perfectMatch, ETH_ADDR_LEN);

    UNSERIALIZE_SCALAR(ioEnable);

    /*
     * unserialize the data fifos
     */
    rxFifo.unserialize("rxFifo", cp, section);
    txFifo.unserialize("txFifo", cp, section);

    /*
     * unserialize the various helper variables
     */
    bool txPacketExists;
    UNSERIALIZE_SCALAR(txPacketExists);
    if (txPacketExists) {
        txPacket = new PacketData(16384);
        txPacket->unserialize("txPacket", cp, section);
        uint32_t txPktBufPtr;
        UNSERIALIZE_SCALAR(txPktBufPtr);
        txPacketBufPtr = (uint8_t *) txPacket->data + txPktBufPtr;
    } else
        txPacket = 0;

    bool rxPacketExists;
    UNSERIALIZE_SCALAR(rxPacketExists);
    rxPacket = 0;
    if (rxPacketExists) {
        rxPacket = new PacketData(16384);
        rxPacket->unserialize("rxPacket", cp, section);
        uint32_t rxPktBufPtr;
        UNSERIALIZE_SCALAR(rxPktBufPtr);
        rxPacketBufPtr = (uint8_t *) rxPacket->data + rxPktBufPtr;
    } else
        rxPacket = 0;

    UNSERIALIZE_SCALAR(txXferLen);
    UNSERIALIZE_SCALAR(rxXferLen);

    /*
     * Unserialize DescCaches
     */
    UNSERIALIZE_SCALAR(txDescCache.link);
    UNSERIALIZE_SCALAR(txDescCache.bufptr);
    UNSERIALIZE_SCALAR(txDescCache.cmdsts);
    UNSERIALIZE_SCALAR(txDescCache.extsts);
    UNSERIALIZE_SCALAR(rxDescCache.link);
    UNSERIALIZE_SCALAR(rxDescCache.bufptr);
    UNSERIALIZE_SCALAR(rxDescCache.cmdsts);
    UNSERIALIZE_SCALAR(rxDescCache.extsts);

    /*
     * unserialize tx state machine
     */
    int txState;
    UNSERIALIZE_SCALAR(txState);
    this->txState = (TxState) txState;
    UNSERIALIZE_SCALAR(txEnable);
    UNSERIALIZE_SCALAR(CTDD);
    UNSERIALIZE_SCALAR(txFragPtr);
    UNSERIALIZE_SCALAR(txDescCnt);
    int txDmaState;
    UNSERIALIZE_SCALAR(txDmaState);
    this->txDmaState = (DmaState) txDmaState;

    /*
     * unserialize rx state machine
     */
    int rxState;
    UNSERIALIZE_SCALAR(rxState);
    this->rxState = (RxState) rxState;
    UNSERIALIZE_SCALAR(rxEnable);
    UNSERIALIZE_SCALAR(CRDD);
    UNSERIALIZE_SCALAR(rxPktBytes);
    UNSERIALIZE_SCALAR(rxFragPtr);
    UNSERIALIZE_SCALAR(rxDescCnt);
    int rxDmaState;
    UNSERIALIZE_SCALAR(rxDmaState);
    this->rxDmaState = (DmaState) rxDmaState;

    UNSERIALIZE_SCALAR(extstsEnable);

     /*
     * If there's a pending transmit, reschedule it now
     */
    Tick transmitTick;
    UNSERIALIZE_SCALAR(transmitTick);
    if (transmitTick)
        txEvent.schedule(curTick + transmitTick);

    /*
     * unserialize receive address filter settings
     */
    UNSERIALIZE_SCALAR(rxFilterEnable);
    UNSERIALIZE_SCALAR(acceptBroadcast);
    UNSERIALIZE_SCALAR(acceptMulticast);
    UNSERIALIZE_SCALAR(acceptUnicast);
    UNSERIALIZE_SCALAR(acceptPerfect);
    UNSERIALIZE_SCALAR(acceptArp);

    /*
     * Keep track of pending interrupt status.
     */
    UNSERIALIZE_SCALAR(intrTick);
    UNSERIALIZE_SCALAR(cpuPendingIntr);
    Tick intrEventTick;
    UNSERIALIZE_SCALAR(intrEventTick);
    if (intrEventTick) {
        intrEvent = new IntrEvent(this, true);
        intrEvent->schedule(intrEventTick);
    }

    /*
     * re-add addrRanges to bus bridges
     */
    if (pioInterface) {
        pioInterface->addAddrRange(RangeSize(BARAddrs[0], BARSize[0]));
        pioInterface->addAddrRange(RangeSize(BARAddrs[1], BARSize[1]));
    }
}

Tick
NSGigE::cacheAccess(MemReqPtr &req)
{
    DPRINTF(EthernetPIO, "timing access to paddr=%#x (daddr=%#x)\n",
            req->paddr, req->paddr - addr);
    return curTick + pioLatency;
}

BEGIN_DECLARE_SIM_OBJECT_PARAMS(NSGigEInt)

    SimObjectParam<EtherInt *> peer;
    SimObjectParam<NSGigE *> device;

END_DECLARE_SIM_OBJECT_PARAMS(NSGigEInt)

BEGIN_INIT_SIM_OBJECT_PARAMS(NSGigEInt)

    INIT_PARAM_DFLT(peer, "peer interface", NULL),
    INIT_PARAM(device, "Ethernet device of this interface")

END_INIT_SIM_OBJECT_PARAMS(NSGigEInt)

CREATE_SIM_OBJECT(NSGigEInt)
{
    NSGigEInt *dev_int = new NSGigEInt(getInstanceName(), device);

    EtherInt *p = (EtherInt *)peer;
    if (p) {
        dev_int->setPeer(p);
        p->setPeer(dev_int);
    }

    return dev_int;
}

REGISTER_SIM_OBJECT("NSGigEInt", NSGigEInt)


BEGIN_DECLARE_SIM_OBJECT_PARAMS(NSGigE)

    Param<Addr> addr;
    Param<Tick> clock;
    Param<Tick> tx_delay;
    Param<Tick> rx_delay;
    Param<Tick> intr_delay;
    SimObjectParam<MemoryController *> mmu;
    SimObjectParam<PhysicalMemory *> physmem;
    Param<bool> rx_filter;
    Param<string> hardware_address;
    SimObjectParam<Bus*> io_bus;
    SimObjectParam<Bus*> payload_bus;
    SimObjectParam<HierParams *> hier;
    Param<Tick> pio_latency;
    Param<bool> dma_desc_free;
    Param<bool> dma_data_free;
    Param<Tick> dma_read_delay;
    Param<Tick> dma_write_delay;
    Param<Tick> dma_read_factor;
    Param<Tick> dma_write_factor;
    SimObjectParam<PciConfigAll *> configspace;
    SimObjectParam<PciConfigData *> configdata;
    SimObjectParam<Platform *> platform;
    Param<uint32_t> pci_bus;
    Param<uint32_t> pci_dev;
    Param<uint32_t> pci_func;
    Param<uint32_t> tx_fifo_size;
    Param<uint32_t> rx_fifo_size;
    Param<uint32_t> m5reg;
    Param<bool> dma_no_allocate;

END_DECLARE_SIM_OBJECT_PARAMS(NSGigE)

BEGIN_INIT_SIM_OBJECT_PARAMS(NSGigE)

    INIT_PARAM(addr, "Device Address"),
    INIT_PARAM(clock, "State machine processor frequency"),
    INIT_PARAM(tx_delay, "Transmit Delay"),
    INIT_PARAM(rx_delay, "Receive Delay"),
    INIT_PARAM(intr_delay, "Interrupt Delay in microseconds"),
    INIT_PARAM(mmu, "Memory Controller"),
    INIT_PARAM(physmem, "Physical Memory"),
    INIT_PARAM_DFLT(rx_filter, "Enable Receive Filter", true),
    INIT_PARAM_DFLT(hardware_address, "Ethernet Hardware Address",
                    "00:99:00:00:00:01"),
    INIT_PARAM_DFLT(io_bus, "The IO Bus to attach to for headers", NULL),
    INIT_PARAM_DFLT(payload_bus, "The IO Bus to attach to for payload", NULL),
    INIT_PARAM_DFLT(hier, "Hierarchy global variables", &defaultHierParams),
    INIT_PARAM_DFLT(pio_latency, "Programmed IO latency in bus cycles", 1),
    INIT_PARAM_DFLT(dma_desc_free, "DMA of Descriptors is free", false),
    INIT_PARAM_DFLT(dma_data_free, "DMA of Data is free", false),
    INIT_PARAM_DFLT(dma_read_delay, "fixed delay for dma reads", 0),
    INIT_PARAM_DFLT(dma_write_delay, "fixed delay for dma writes", 0),
    INIT_PARAM_DFLT(dma_read_factor, "multiplier for dma reads", 0),
    INIT_PARAM_DFLT(dma_write_factor, "multiplier for dma writes", 0),
    INIT_PARAM(configspace, "PCI Configspace"),
    INIT_PARAM(configdata, "PCI Config data"),
    INIT_PARAM(platform, "Platform"),
    INIT_PARAM(pci_bus, "PCI bus"),
    INIT_PARAM(pci_dev, "PCI device number"),
    INIT_PARAM(pci_func, "PCI function code"),
    INIT_PARAM_DFLT(tx_fifo_size, "max size in bytes of txFifo", 131072),
    INIT_PARAM_DFLT(rx_fifo_size, "max size in bytes of rxFifo", 131072),
    INIT_PARAM(m5reg, "m5 register"),
    INIT_PARAM_DFLT(dma_no_allocate, "Should DMA reads allocate cache lines", true)

END_INIT_SIM_OBJECT_PARAMS(NSGigE)


CREATE_SIM_OBJECT(NSGigE)
{
    NSGigE::Params *params = new NSGigE::Params;

    params->name = getInstanceName();
    params->mmu = mmu;
    params->configSpace = configspace;
    params->configData = configdata;
    params->plat = platform;
    params->busNum = pci_bus;
    params->deviceNum = pci_dev;
    params->functionNum = pci_func;

    params->clock = clock;
    params->intr_delay = intr_delay;
    params->pmem = physmem;
    params->tx_delay = tx_delay;
    params->rx_delay = rx_delay;
    params->hier = hier;
    params->header_bus = io_bus;
    params->payload_bus = payload_bus;
    params->pio_latency = pio_latency;
    params->dma_desc_free = dma_desc_free;
    params->dma_data_free = dma_data_free;
    params->dma_read_delay = dma_read_delay;
    params->dma_write_delay = dma_write_delay;
    params->dma_read_factor = dma_read_factor;
    params->dma_write_factor = dma_write_factor;
    params->rx_filter = rx_filter;
    params->eaddr = hardware_address;
    params->tx_fifo_size = tx_fifo_size;
    params->rx_fifo_size = rx_fifo_size;
    params->m5reg = m5reg;
    params->dma_no_allocate = dma_no_allocate;
    return new NSGigE(params);
}

REGISTER_SIM_OBJECT("NSGigE", NSGigE)