src/dev/storage/ide_ctrl.cc - public/gem5 - Git at Google

 /*
  * Copyright (c) 2013 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
  * not be construed as granting a license to any other intellectual
  * property including but not limited to intellectual property relating
  * to a hardware implementation of the functionality of the software
  * licensed hereunder.  You may use the software subject to the license
  * terms below provided that you ensure that this notice is replicated
  * unmodified and in its entirety in all distributions of the software,
  * modified or unmodified, in source code or in binary form.
  *
  * 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.
  */

 #include "dev/storage/ide_ctrl.hh"

 #include <string>

 #include "base/cprintf.hh"
 #include "debug/IdeCtrl.hh"
 #include "dev/storage/ide_disk.hh"
 #include "mem/packet.hh"
 #include "mem/packet_access.hh"
 #include "params/IdeController.hh"
 #include "sim/byteswap.hh"

 namespace gem5
 {

 // Bus master IDE registers
 enum BMIRegOffset
 {
     BMICommand = 0x0,
     BMIStatus = 0x2,
     BMIDescTablePtr = 0x4
 };

 IdeController::Channel::Channel(std::string new_name, IdeController *new_ctrl,
         bool new_primary) :
     Named(new_name), ctrl(new_ctrl), primary(new_primary)
 {
     bmiRegs.reset();
     bmiRegs.status.dmaCap0 = 1;
     bmiRegs.status.dmaCap1 = 1;
 }

 IdeController::IdeController(const Params &p)
     : PciDevice(p), configSpaceRegs(name() + ".config_space_regs"),
     primary(name() + ".primary", this, true),
     secondary(name() + ".secondary", this, false),
     ioShift(p.io_shift), ctrlOffset(p.ctrl_offset)
 {
     panic_if(params().disks.size() > 3,
             "IDE controllers support a maximum of 4 devices attached!");

     // Assign the disks to channels
     for (int i = 0; i < params().disks.size(); i++) {
         auto *disk = params().disks[i];
         auto &channel = (i < 2) ? primary : secondary;

         if (!disk)
             continue;

         if (i % 2 == 0)
             channel.setDevice0(disk);
         else
             channel.setDevice1(disk);

         // Arbitrarily set the chunk size to 4K.
         disk->setChannel(&channel, 4 * 1024);
     }

     primary.select(false);
     secondary.select(false);
 }

 void
 IdeController::ConfigSpaceRegs::serialize(CheckpointOut &cp) const
 {
     SERIALIZE_SCALAR(primaryTiming);
     SERIALIZE_SCALAR(secondaryTiming);
     SERIALIZE_SCALAR(deviceTiming);
     SERIALIZE_SCALAR(udmaControl);
     SERIALIZE_SCALAR(udmaTiming);
 }

 void
 IdeController::ConfigSpaceRegs::unserialize(CheckpointIn &cp)
 {
     UNSERIALIZE_SCALAR(primaryTiming);
     UNSERIALIZE_SCALAR(secondaryTiming);
     UNSERIALIZE_SCALAR(deviceTiming);
     UNSERIALIZE_SCALAR(udmaControl);
     UNSERIALIZE_SCALAR(udmaTiming);
 }

 void
 IdeController::Channel::postInterrupt()
 {
     bmiRegs.status.intStatus = 1;
     _pendingInterrupt = true;
     ctrl->postInterrupt(isPrimary());
 }

 void
 IdeController::Channel::clearInterrupt()
 {
     bmiRegs.status.intStatus = 0;
     _pendingInterrupt = false;
     ctrl->clearInterrupt(isPrimary());
 }

 void
 IdeController::postInterrupt(bool is_primary)
 {
     auto &other = is_primary ? secondary : primary;
     // If an interrupt isn't already posted for the other channel...
     if (!other.pendingInterrupt())
         PciDevice::intrPost();
 }

 void
 IdeController::clearInterrupt(bool is_primary)
 {
     auto &other = is_primary ? secondary : primary;
     // If the interrupt isn't still needed by the other channel...
     if (!other.pendingInterrupt())
         PciDevice::intrClear();
 }

 Tick
 IdeController::readConfig(PacketPtr pkt)
 {
     int offset = pkt->getAddr() & PCI_CONFIG_SIZE;
     if (offset < PCI_DEVICE_SPECIFIC)
         return PciDevice::readConfig(pkt);

     size_t size = pkt->getSize();

     configSpaceRegs.read(offset, pkt->getPtr<void>(), size);

     DPRINTF(IdeCtrl, "PCI read offset: %#x size: %d data: %#x\n", offset, size,
             pkt->getUintX(ByteOrder::little));

     pkt->makeAtomicResponse();
     return configDelay;
 }


 Tick
 IdeController::writeConfig(PacketPtr pkt)
 {
     int offset = pkt->getAddr() & PCI_CONFIG_SIZE;

     if (offset < PCI_DEVICE_SPECIFIC)
         return PciDevice::writeConfig(pkt);

     size_t size = pkt->getSize();

     DPRINTF(IdeCtrl, "PCI write offset: %#x size: %d data: %#x\n",
             offset, size, pkt->getUintX(ByteOrder::little));

     configSpaceRegs.write(offset, pkt->getConstPtr<void>(), size);

     pkt->makeAtomicResponse();
     return configDelay;
 }

 void
 IdeController::Channel::accessCommand(Addr offset,
         int size, uint8_t *data, bool read)
 {
     const Addr SelectOffset = 6;
     const uint8_t SelectDevBit = 0x10;

     if (!read && offset == SelectOffset)
         select(*data & SelectDevBit);

     if (selected() == NULL) {
         assert(size == sizeof(uint8_t));
         *data = 0;
     } else if (read) {
         selected()->readCommand(offset, size, data);
     } else {
         selected()->writeCommand(offset, size, data);
     }
 }

 void
 IdeController::Channel::accessControl(Addr offset,
         int size, uint8_t *data, bool read)
 {
     if (selected() == NULL) {
         assert(size == sizeof(uint8_t));
         *data = 0;
     } else if (read) {
         selected()->readControl(offset, size, data);
     } else {
         selected()->writeControl(offset, size, data);
     }
 }

 void
 IdeController::Channel::accessBMI(Addr offset,
         int size, uint8_t *data, bool read)
 {
     assert(offset + size <= sizeof(BMIRegs));
     if (read) {
         memcpy(data, (uint8_t *)&bmiRegs + offset, size);
     } else {
         switch (offset) {
           case BMICommand:
             {
                 if (size != sizeof(uint8_t))
                     panic("Invalid BMIC write size: %x\n", size);

                 BMICommandReg oldVal = bmiRegs.command;
                 BMICommandReg newVal = *data;

                 // if a DMA transfer is in progress, R/W control cannot change
                 if (oldVal.startStop && oldVal.rw != newVal.rw)
                     oldVal.rw = newVal.rw;

                 if (oldVal.startStop != newVal.startStop) {
                     if (selected() == NULL)
                         panic("DMA start for disk which does not exist\n");

                     if (oldVal.startStop) {
                         DPRINTF(IdeCtrl, "Stopping DMA transfer\n");
                         bmiRegs.status.active = 0;

                         selected()->abortDma();
                     } else {
                         DPRINTF(IdeCtrl, "Starting DMA transfer\n");
                         bmiRegs.status.active = 1;

                         selected()->startDma(letoh(bmiRegs.bmidtp));
                     }
                 }

                 bmiRegs.command = newVal;
             }
             break;
           case BMIStatus:
             {
                 if (size != sizeof(uint8_t))
                     panic("Invalid BMIS write size: %x\n", size);

                 BMIStatusReg oldVal = bmiRegs.status;
                 BMIStatusReg newVal = *data;

                 // the BMIDEA bit is read only
                 newVal.active = oldVal.active;

                 // to reset (set 0) IDEINTS and IDEDMAE, write 1 to each
                 if ((oldVal.intStatus == 1) && (newVal.intStatus == 1)) {
                     newVal.intStatus = 0; // clear the interrupt?
                 } else {
                     // Assigning two bitunion fields to each other does not
                     // work as intended, so we need to use this temporary
                     // variable to get around the bug.
                     uint8_t tmp = oldVal.intStatus;
                     newVal.intStatus = tmp;
                 }
                 if ((oldVal.dmaError == 1) && (newVal.dmaError == 1)) {
                     newVal.dmaError = 0;
                 } else {
                     uint8_t tmp = oldVal.dmaError;
                     newVal.dmaError = tmp;
                 }

                 bmiRegs.status = newVal;
             }
             break;
           case BMIDescTablePtr:
             if (size != sizeof(uint32_t))
                 panic("Invalid BMIDTP write size: %x\n", size);
             bmiRegs.bmidtp = htole(*(uint32_t *)data & ~0x3);
             break;
           default:
             if (size != sizeof(uint8_t) && size != sizeof(uint16_t) &&
                     size != sizeof(uint32_t)) {
                 panic("IDE controller write of invalid size: %x\n", size);
             }
             memcpy((uint8_t *)&bmiRegs + offset, data, size);
         }
     }
 }

 void
 IdeController::dispatchAccess(PacketPtr pkt, bool read)
 {
     if (pkt->getSize() != 1 && pkt->getSize() != 2 && pkt->getSize() !=4)
          panic("Bad IDE read size: %d\n", pkt->getSize());

     Addr addr = pkt->getAddr();
     int size = pkt->getSize();
     uint8_t *dataPtr = pkt->getPtr<uint8_t>();

     int bar_num;
     Addr offset;
     panic_if(!getBAR(addr, bar_num, offset),
         "IDE controller access to invalid address: %#x.", addr);

     switch (bar_num) {
       case 0:
         // linux may have shifted the address by ioShift,
         // here we shift it back, similarly for ctrlOffset.
         offset >>= ioShift;
         primary.accessCommand(offset, size, dataPtr, read);
         break;
       case 1:
         offset += ctrlOffset;
         primary.accessControl(offset, size, dataPtr, read);
         break;
       case 2:
         secondary.accessCommand(offset, size, dataPtr, read);
         break;
       case 3:
         secondary.accessControl(offset, size, dataPtr, read);
         break;
       case 4:
         {
             PciCommandRegister command = letoh(config.command);
             if (!read && !command.busMaster)
                 return;

             if (offset < sizeof(Channel::BMIRegs)) {
                 primary.accessBMI(offset, size, dataPtr, read);
             } else {
                 offset -= sizeof(Channel::BMIRegs);
                 secondary.accessBMI(offset, size, dataPtr, read);
             }
         }
     }

 #ifndef NDEBUG
     uint32_t data;
     if (pkt->getSize() == 1)
         data = pkt->getLE<uint8_t>();
     else if (pkt->getSize() == 2)
         data = pkt->getLE<uint16_t>();
     else
         data = pkt->getLE<uint32_t>();
     DPRINTF(IdeCtrl, "%s from offset: %#x size: %#x data: %#x\n",
             read ? "Read" : "Write", pkt->getAddr(), pkt->getSize(), data);
 #endif

     pkt->makeAtomicResponse();
 }

 void
 IdeController::Channel::setDmaComplete()
 {
     bmiRegs.command.startStop = 0;
     bmiRegs.status.active = 0;
     bmiRegs.status.intStatus = 1;
 }

 Tick
 IdeController::read(PacketPtr pkt)
 {
     dispatchAccess(pkt, true);
     return pioDelay;
 }

 Tick
 IdeController::write(PacketPtr pkt)
 {
     dispatchAccess(pkt, false);
     return pioDelay;
 }

 void
 IdeController::serialize(CheckpointOut &cp) const
 {
     // Serialize the PciDevice base class
     PciDevice::serialize(cp);

     // Serialize channels
     primary.serialize("primary", cp);
     secondary.serialize("secondary", cp);

     // Serialize config registers
     configSpaceRegs.serialize(cp);
 }

 void
 IdeController::Channel::serialize(const std::string &base,
                                   CheckpointOut &cp) const
 {
     uint8_t command = bmiRegs.command;
     paramOut(cp, base + ".bmiRegs.command", command);
     paramOut(cp, base + ".bmiRegs.reserved0", bmiRegs.reserved0);
     uint8_t status = bmiRegs.status;
     paramOut(cp, base + ".bmiRegs.status", status);
     paramOut(cp, base + ".bmiRegs.reserved1", bmiRegs.reserved1);
     paramOut(cp, base + ".bmiRegs.bmidtp", bmiRegs.bmidtp);
     paramOut(cp, base + ".selectBit", selectBit);
 }

 void
 IdeController::unserialize(CheckpointIn &cp)
 {
     // Unserialize the PciDevice base class
     PciDevice::unserialize(cp);

     // Unserialize channels
     primary.unserialize("primary", cp);
     secondary.unserialize("secondary", cp);

     // Unserialize config registers
     configSpaceRegs.unserialize(cp);
 }

 void
 IdeController::Channel::unserialize(const std::string &base, CheckpointIn &cp)
 {
     uint8_t command;
     paramIn(cp, base +".bmiRegs.command", command);
     bmiRegs.command = command;
     paramIn(cp, base + ".bmiRegs.reserved0", bmiRegs.reserved0);
     uint8_t status;
     paramIn(cp, base + ".bmiRegs.status", status);
     bmiRegs.status = status;
     paramIn(cp, base + ".bmiRegs.reserved1", bmiRegs.reserved1);
     paramIn(cp, base + ".bmiRegs.bmidtp", bmiRegs.bmidtp);
     paramIn(cp, base + ".selectBit", selectBit);
     select(selectBit);
 }

 } // namespace gem5
	/*
	* Copyright (c) 2013 ARM Limited
	* All rights reserved
	*
	* The license below extends only to copyright in the software and shall
	* not be construed as granting a license to any other intellectual
	* property including but not limited to intellectual property relating
	* to a hardware implementation of the functionality of the software
	* licensed hereunder. You may use the software subject to the license
	* terms below provided that you ensure that this notice is replicated
	* unmodified and in its entirety in all distributions of the software,
	* modified or unmodified, in source code or in binary form.
	*
	* 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.
	*/

	#include "dev/storage/ide_ctrl.hh"

	#include <string>

	#include "base/cprintf.hh"
	#include "debug/IdeCtrl.hh"
	#include "dev/storage/ide_disk.hh"
	#include "mem/packet.hh"
	#include "mem/packet_access.hh"
	#include "params/IdeController.hh"
	#include "sim/byteswap.hh"

	namespace gem5
	{

	// Bus master IDE registers
	enum BMIRegOffset
	{
	BMICommand = 0x0,
	BMIStatus = 0x2,
	BMIDescTablePtr = 0x4
	};

	IdeController::Channel::Channel(std::string new_name, IdeController *new_ctrl,
	bool new_primary) :
	Named(new_name), ctrl(new_ctrl), primary(new_primary)
	{
	bmiRegs.reset();
	bmiRegs.status.dmaCap0 = 1;
	bmiRegs.status.dmaCap1 = 1;
	}

	IdeController::IdeController(const Params &p)
	: PciDevice(p), configSpaceRegs(name() + ".config_space_regs"),
	primary(name() + ".primary", this, true),
	secondary(name() + ".secondary", this, false),
	ioShift(p.io_shift), ctrlOffset(p.ctrl_offset)
	{
	panic_if(params().disks.size() > 3,
	"IDE controllers support a maximum of 4 devices attached!");

	// Assign the disks to channels
	for (int i = 0; i < params().disks.size(); i++) {
	auto *disk = params().disks[i];
	auto &channel = (i < 2) ? primary : secondary;

	if (!disk)
	continue;

	if (i % 2 == 0)
	channel.setDevice0(disk);
	else
	channel.setDevice1(disk);

	// Arbitrarily set the chunk size to 4K.
	disk->setChannel(&channel, 4 * 1024);
	}

	primary.select(false);
	secondary.select(false);
	}

	void
	IdeController::ConfigSpaceRegs::serialize(CheckpointOut &cp) const
	{
	SERIALIZE_SCALAR(primaryTiming);
	SERIALIZE_SCALAR(secondaryTiming);
	SERIALIZE_SCALAR(deviceTiming);
	SERIALIZE_SCALAR(udmaControl);
	SERIALIZE_SCALAR(udmaTiming);
	}

	void
	IdeController::ConfigSpaceRegs::unserialize(CheckpointIn &cp)
	{
	UNSERIALIZE_SCALAR(primaryTiming);
	UNSERIALIZE_SCALAR(secondaryTiming);
	UNSERIALIZE_SCALAR(deviceTiming);
	UNSERIALIZE_SCALAR(udmaControl);
	UNSERIALIZE_SCALAR(udmaTiming);
	}

	void
	IdeController::Channel::postInterrupt()
	{
	bmiRegs.status.intStatus = 1;
	_pendingInterrupt = true;
	ctrl->postInterrupt(isPrimary());
	}

	void
	IdeController::Channel::clearInterrupt()
	{
	bmiRegs.status.intStatus = 0;
	_pendingInterrupt = false;
	ctrl->clearInterrupt(isPrimary());
	}

	void
	IdeController::postInterrupt(bool is_primary)
	{
	auto &other = is_primary ? secondary : primary;
	// If an interrupt isn't already posted for the other channel...
	if (!other.pendingInterrupt())
	PciDevice::intrPost();
	}

	void
	IdeController::clearInterrupt(bool is_primary)
	{
	auto &other = is_primary ? secondary : primary;
	// If the interrupt isn't still needed by the other channel...
	if (!other.pendingInterrupt())
	PciDevice::intrClear();
	}

	Tick
	IdeController::readConfig(PacketPtr pkt)
	{
	int offset = pkt->getAddr() & PCI_CONFIG_SIZE;
	if (offset < PCI_DEVICE_SPECIFIC)
	return PciDevice::readConfig(pkt);

	size_t size = pkt->getSize();

	configSpaceRegs.read(offset, pkt->getPtr<void>(), size);

	DPRINTF(IdeCtrl, "PCI read offset: %#x size: %d data: %#x\n", offset, size,
	pkt->getUintX(ByteOrder::little));

	pkt->makeAtomicResponse();
	return configDelay;
	}


	Tick
	IdeController::writeConfig(PacketPtr pkt)
	{
	int offset = pkt->getAddr() & PCI_CONFIG_SIZE;

	if (offset < PCI_DEVICE_SPECIFIC)
	return PciDevice::writeConfig(pkt);

	size_t size = pkt->getSize();

	DPRINTF(IdeCtrl, "PCI write offset: %#x size: %d data: %#x\n",
	offset, size, pkt->getUintX(ByteOrder::little));

	configSpaceRegs.write(offset, pkt->getConstPtr<void>(), size);

	pkt->makeAtomicResponse();
	return configDelay;
	}

	void
	IdeController::Channel::accessCommand(Addr offset,
	int size, uint8_t *data, bool read)
	{
	const Addr SelectOffset = 6;
	const uint8_t SelectDevBit = 0x10;

	if (!read && offset == SelectOffset)
	select(*data & SelectDevBit);

	if (selected() == NULL) {
	assert(size == sizeof(uint8_t));
	*data = 0;
	} else if (read) {
	selected()->readCommand(offset, size, data);
	} else {
	selected()->writeCommand(offset, size, data);
	}
	}

	void
	IdeController::Channel::accessControl(Addr offset,
	int size, uint8_t *data, bool read)
	{
	if (selected() == NULL) {
	assert(size == sizeof(uint8_t));
	*data = 0;
	} else if (read) {
	selected()->readControl(offset, size, data);
	} else {
	selected()->writeControl(offset, size, data);
	}
	}

	void
	IdeController::Channel::accessBMI(Addr offset,
	int size, uint8_t *data, bool read)
	{
	assert(offset + size <= sizeof(BMIRegs));
	if (read) {
	memcpy(data, (uint8_t *)&bmiRegs + offset, size);
	} else {
	switch (offset) {
	case BMICommand:
	{
	if (size != sizeof(uint8_t))
	panic("Invalid BMIC write size: %x\n", size);

	BMICommandReg oldVal = bmiRegs.command;
	BMICommandReg newVal = *data;

	// if a DMA transfer is in progress, R/W control cannot change
	if (oldVal.startStop && oldVal.rw != newVal.rw)
	oldVal.rw = newVal.rw;

	if (oldVal.startStop != newVal.startStop) {
	if (selected() == NULL)
	panic("DMA start for disk which does not exist\n");

	if (oldVal.startStop) {
	DPRINTF(IdeCtrl, "Stopping DMA transfer\n");
	bmiRegs.status.active = 0;

	selected()->abortDma();
	} else {
	DPRINTF(IdeCtrl, "Starting DMA transfer\n");
	bmiRegs.status.active = 1;

	selected()->startDma(letoh(bmiRegs.bmidtp));
	}
	}

	bmiRegs.command = newVal;
	}
	break;
	case BMIStatus:
	{
	if (size != sizeof(uint8_t))
	panic("Invalid BMIS write size: %x\n", size);

	BMIStatusReg oldVal = bmiRegs.status;
	BMIStatusReg newVal = *data;

	// the BMIDEA bit is read only
	newVal.active = oldVal.active;

	// to reset (set 0) IDEINTS and IDEDMAE, write 1 to each
	if ((oldVal.intStatus == 1) && (newVal.intStatus == 1)) {
	newVal.intStatus = 0; // clear the interrupt?
	} else {
	// Assigning two bitunion fields to each other does not
	// work as intended, so we need to use this temporary
	// variable to get around the bug.
	uint8_t tmp = oldVal.intStatus;
	newVal.intStatus = tmp;
	}
	if ((oldVal.dmaError == 1) && (newVal.dmaError == 1)) {
	newVal.dmaError = 0;
	} else {
	uint8_t tmp = oldVal.dmaError;
	newVal.dmaError = tmp;
	}

	bmiRegs.status = newVal;
	}
	break;
	case BMIDescTablePtr:
	if (size != sizeof(uint32_t))
	panic("Invalid BMIDTP write size: %x\n", size);
	bmiRegs.bmidtp = htole((uint32_t )data & ~0x3);
	break;
	default:
	if (size != sizeof(uint8_t) && size != sizeof(uint16_t) &&
	size != sizeof(uint32_t)) {
	panic("IDE controller write of invalid size: %x\n", size);
	}
	memcpy((uint8_t *)&bmiRegs + offset, data, size);
	}
	}
	}

	void
	IdeController::dispatchAccess(PacketPtr pkt, bool read)
	{
	if (pkt->getSize() != 1 && pkt->getSize() != 2 && pkt->getSize() !=4)
	panic("Bad IDE read size: %d\n", pkt->getSize());

	Addr addr = pkt->getAddr();
	int size = pkt->getSize();
	uint8_t *dataPtr = pkt->getPtr<uint8_t>();

	int bar_num;
	Addr offset;
	panic_if(!getBAR(addr, bar_num, offset),
	"IDE controller access to invalid address: %#x.", addr);

	switch (bar_num) {
	case 0:
	// linux may have shifted the address by ioShift,
	// here we shift it back, similarly for ctrlOffset.
	offset >>= ioShift;
	primary.accessCommand(offset, size, dataPtr, read);
	break;
	case 1:
	offset += ctrlOffset;
	primary.accessControl(offset, size, dataPtr, read);
	break;
	case 2:
	secondary.accessCommand(offset, size, dataPtr, read);
	break;
	case 3:
	secondary.accessControl(offset, size, dataPtr, read);
	break;
	case 4:
	{
	PciCommandRegister command = letoh(config.command);
	if (!read && !command.busMaster)
	return;

	if (offset < sizeof(Channel::BMIRegs)) {
	primary.accessBMI(offset, size, dataPtr, read);
	} else {
	offset -= sizeof(Channel::BMIRegs);
	secondary.accessBMI(offset, size, dataPtr, read);
	}
	}
	}

	#ifndef NDEBUG
	uint32_t data;
	if (pkt->getSize() == 1)
	data = pkt->getLE<uint8_t>();
	else if (pkt->getSize() == 2)
	data = pkt->getLE<uint16_t>();
	else
	data = pkt->getLE<uint32_t>();
	DPRINTF(IdeCtrl, "%s from offset: %#x size: %#x data: %#x\n",
	read ? "Read" : "Write", pkt->getAddr(), pkt->getSize(), data);
	#endif

	pkt->makeAtomicResponse();
	}

	void
	IdeController::Channel::setDmaComplete()
	{
	bmiRegs.command.startStop = 0;
	bmiRegs.status.active = 0;
	bmiRegs.status.intStatus = 1;
	}

	Tick
	IdeController::read(PacketPtr pkt)
	{
	dispatchAccess(pkt, true);
	return pioDelay;
	}

	Tick
	IdeController::write(PacketPtr pkt)
	{
	dispatchAccess(pkt, false);
	return pioDelay;
	}

	void
	IdeController::serialize(CheckpointOut &cp) const
	{
	// Serialize the PciDevice base class
	PciDevice::serialize(cp);

	// Serialize channels
	primary.serialize("primary", cp);
	secondary.serialize("secondary", cp);

	// Serialize config registers
	configSpaceRegs.serialize(cp);
	}

	void
	IdeController::Channel::serialize(const std::string &base,
	CheckpointOut &cp) const
	{
	uint8_t command = bmiRegs.command;
	paramOut(cp, base + ".bmiRegs.command", command);
	paramOut(cp, base + ".bmiRegs.reserved0", bmiRegs.reserved0);
	uint8_t status = bmiRegs.status;
	paramOut(cp, base + ".bmiRegs.status", status);
	paramOut(cp, base + ".bmiRegs.reserved1", bmiRegs.reserved1);
	paramOut(cp, base + ".bmiRegs.bmidtp", bmiRegs.bmidtp);
	paramOut(cp, base + ".selectBit", selectBit);
	}

	void
	IdeController::unserialize(CheckpointIn &cp)
	{
	// Unserialize the PciDevice base class
	PciDevice::unserialize(cp);

	// Unserialize channels
	primary.unserialize("primary", cp);
	secondary.unserialize("secondary", cp);

	// Unserialize config registers
	configSpaceRegs.unserialize(cp);
	}

	void
	IdeController::Channel::unserialize(const std::string &base, CheckpointIn &cp)
	{
	uint8_t command;
	paramIn(cp, base +".bmiRegs.command", command);
	bmiRegs.command = command;
	paramIn(cp, base + ".bmiRegs.reserved0", bmiRegs.reserved0);
	uint8_t status;
	paramIn(cp, base + ".bmiRegs.status", status);
	bmiRegs.status = status;
	paramIn(cp, base + ".bmiRegs.reserved1", bmiRegs.reserved1);
	paramIn(cp, base + ".bmiRegs.bmidtp", bmiRegs.bmidtp);
	paramIn(cp, base + ".selectBit", selectBit);
	select(selectBit);
	}

	} // namespace gem5