src/mem/cfi_mem.cc - public/gem5 - Git at Google

 /*
  * Copyright (c) 2010-2013, 2015, 2021 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) 2001-2005 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 "mem/cfi_mem.hh"

 #include <cmath>

 #include "base/intmath.hh"
 #include "base/random.hh"
 #include "base/trace.hh"
 #include "debug/CFI.hh"
 #include "debug/Drain.hh"

 namespace gem5
 {

 namespace memory
 {

 bool
 CfiMemory::BlockData::isLocked(Addr block_address) const
 {
     return locked[blockIdx(block_address)];
 }

 void
 CfiMemory::BlockData::lock(Addr block_address)
 {
     locked[blockIdx(block_address)] = true;
 }

 void
 CfiMemory::BlockData::unlock(Addr block_address)
 {
     locked[blockIdx(block_address)] = false;
 }

 void
 CfiMemory::BlockData::serialize(CheckpointOut &cp) const
 {
     SERIALIZE_CONTAINER(locked);
 }

 void
 CfiMemory::BlockData::unserialize(CheckpointIn &cp)
 {
     UNSERIALIZE_CONTAINER(locked);
 }

 uint32_t
 CfiMemory::BlockData::blockIdx(Addr block_address) const
 {
     return block_address / blockSize;
 }

 void
 CfiMemory::ProgramBuffer::setup(ssize_t buffer_size)
 {
     /** Clipping the size to its limit */
     if (buffer_size > MAX_BUFFER_SIZE) {
         buffer_size = MAX_BUFFER_SIZE;
     }

     buffer.resize(buffer_size);
     std::fill(buffer.begin(), buffer.end(), 0);
     bytesWritten = 0;
 }

 bool
 CfiMemory::ProgramBuffer::write(Addr flash_address,
     void *data_ptr, ssize_t size)
 {
     if (bytesWritten >= buffer.size())
         return true;

     if (bytesWritten == 0) {
         blockPointer = flash_address;
     }

     const Addr offset = flash_address - blockPointer;

     if (flash_address < blockPointer || offset >= MAX_BUFFER_SIZE)
         return true;

     std::memcpy(buffer.data() + offset, data_ptr, size);
     bytesWritten += size;

     return false;
 }

 bool
 CfiMemory::ProgramBuffer::writeback()
 {
     if (parent.blocks.isLocked(blockPointer)) {
         return false;
     } else {
         std::memcpy(parent.toHostAddr(parent.start() + blockPointer),
             buffer.data(), bytesWritten);
         return true;
     }
 }

 void
 CfiMemory::ProgramBuffer::serialize(CheckpointOut &cp) const
 {
     SERIALIZE_CONTAINER(buffer);
     SERIALIZE_SCALAR(bytesWritten);
     SERIALIZE_SCALAR(blockPointer);
 }

 void
 CfiMemory::ProgramBuffer::unserialize(CheckpointIn &cp)
 {
     UNSERIALIZE_CONTAINER(buffer);
     UNSERIALIZE_SCALAR(bytesWritten);
     UNSERIALIZE_SCALAR(blockPointer);
 }

 CfiMemory::CfiMemory(const CfiMemoryParams &p)
   : AbstractMemory(p),
     port(name() + ".port", *this), latency(p.latency),
     latency_var(p.latency_var), bandwidth(p.bandwidth), isBusy(false),
     retryReq(false), retryResp(false),
     releaseEvent([this]{ release(); }, name()),
     dequeueEvent([this]{ dequeue(); }, name()),
     numberOfChips(2),
     vendorID(p.vendor_id),
     deviceID(p.device_id),
     bankWidth(p.bank_width),
     readState(CfiCommand::READ_ARRAY), writeState(CfiCommand::NO_CMD),
     statusRegister(STATUS_READY),
     blocks(*this, size() / p.blk_size, p.blk_size),
     programBuffer(*this),
     cfiQueryTable{
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         /* Query-unique ASCII string */
         'Q', 'R', 'Y',
         /* Primary Algorithm Command Set and Control = Intel/Sharp */
         0x01, 0x00,
         /* Address for Primary Algorithm extended Query */
         0x31, 0x00,
         /* Alternative Algorithm Command Set and Control Interface */
         0x00, 0x00,
         /* Address for Alternative Algorithm extended Query */
         0x00, 0x00,
         /* Vcc Minimum Program/Erase or Write voltage ([7:4].[3-0]V) */
         0x45,
         /* Vcc Maximum Program/Erase or Write voltage ([7:4].[3-0]V) */
         0x55,
         /* Vpp Minimum Program/Erase voltage (0 = No Vpp pin) */
         0x00,
         /* Vpp Minimum Program/Erase voltage (0 = No Vpp pin) */
         0x00,
         /* Typical timeout per single byte/word/D-word program: (2^N us) */
         0x01,
         /* Typical timeout for maximum-size multi-byte program: (2^N us) */
         0x01,
         /* Typical timeout per individual block erase: (2^N ms) */
         0x01,
         /* Typical timeout for full chip erase: (2^N ms) */
         0x00,
         /* Maximum timeout for byte/word/D-word program (2^N typical) */
         0x00,
         /* Maximum timeout for multi-byte program (2^N typical) */
         0x00,
         /* Maximum timeout per individual block erase (2^N typical) */
         0x00,
         /* Maximum timeout for chip erase (2^N typical) */
         0x00,
         /* Device Size in number of bytes (2^N) */
         static_cast<uint8_t>(log2(size())),
         /* Flash Device Interface Code description */
         0x05, 0x00,
         /* Maximum number of bytes in multi-byte program (2^N) */
         static_cast<uint8_t>(bits(log2i(ProgramBuffer::MAX_BUFFER_SIZE), 7, 0)),
         static_cast<uint8_t>(bits(log2i(ProgramBuffer::MAX_BUFFER_SIZE), 15, 8)),
         /* Number of Erase Block Regions within device */
         0x01,
         /* Erase Block Region Information */
         static_cast<uint8_t>(bits(blocks.number(), 7, 0)),
         static_cast<uint8_t>(bits(blocks.number(), 15, 8)),
         static_cast<uint8_t>(bits(blocks.size(), 7, 0)),
         static_cast<uint8_t>(bits(blocks.size(), 15, 8)),
     }
 {}

 void
 CfiMemory::init()
 {
     AbstractMemory::init();

     // allow unconnected memories as this is used in several ruby
     // systems at the moment
     if (port.isConnected()) {
         port.sendRangeChange();
     }
 }

 Tick
 CfiMemory::recvAtomic(PacketPtr pkt)
 {
     panic_if(pkt->cacheResponding(), "Should not see packets where cache "
              "is responding");

     cfiAccess(pkt);
     return getLatency();
 }

 Tick
 CfiMemory::recvAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &_backdoor)
 {
     Tick latency = recvAtomic(pkt);

     if (backdoor.ptr())
         _backdoor = &backdoor;
     return latency;
 }

 void
 CfiMemory::recvFunctional(PacketPtr pkt)
 {
     pkt->pushLabel(name());

     functionalAccess(pkt);

     bool done = false;
     auto p = packetQueue.begin();
     // potentially update the packets in our packet queue as well
     while (!done && p != packetQueue.end()) {
         done = pkt->trySatisfyFunctional(p->pkt);
         ++p;
     }

     pkt->popLabel();
 }

 bool
 CfiMemory::recvTimingReq(PacketPtr pkt)
 {
     panic_if(pkt->cacheResponding(), "Should not see packets where cache "
              "is responding");

     panic_if(!(pkt->isRead() || pkt->isWrite()),
              "Should only see read and writes at memory controller, "
              "saw %s to %#llx\n", pkt->cmdString(), pkt->getAddr());

     // we should not get a new request after committing to retry the
     // current one, but unfortunately the CPU violates this rule, so
     // simply ignore it for now
     if (retryReq)
         return false;

     // if we are busy with a read or write, remember that we have to
     // retry
     if (isBusy) {
         retryReq = true;
         return false;
     }

     // technically the packet only reaches us after the header delay,
     // and since this is a memory controller we also need to
     // deserialise the payload before performing any write operation
     Tick receive_delay = pkt->headerDelay + pkt->payloadDelay;
     pkt->headerDelay = pkt->payloadDelay = 0;

     // update the release time according to the bandwidth limit, and
     // do so with respect to the time it takes to finish this request
     // rather than long term as it is the short term data rate that is
     // limited for any real memory

     // calculate an appropriate tick to release to not exceed
     // the bandwidth limit
     Tick duration = pkt->getSize() * bandwidth;

     // only consider ourselves busy if there is any need to wait
     // to avoid extra events being scheduled for (infinitely) fast
     // memories
     if (duration != 0) {
         schedule(releaseEvent, curTick() + duration);
         isBusy = true;
     }

     // go ahead and deal with the packet and put the response in the
     // queue if there is one
     bool needs_response = pkt->needsResponse();
     recvAtomic(pkt);
     // turn packet around to go back to requester if response expected
     if (needs_response) {
         // recvAtomic() should already have turned packet into
         // atomic response
         assert(pkt->isResponse());

         Tick when_to_send = curTick() + receive_delay + getLatency();

         // typically this should be added at the end, so start the
         // insertion sort with the last element, also make sure not to
         // re-order in front of some existing packet with the same
         // address, the latter is important as this memory effectively
         // hands out exclusive copies (shared is not asserted)
         auto i = packetQueue.end();
         --i;
         while (i != packetQueue.begin() && when_to_send < i->tick &&
                !i->pkt->matchAddr(pkt)) {
             --i;
         }

         // emplace inserts the element before the position pointed to by
         // the iterator, so advance it one step
         packetQueue.emplace(++i, pkt, when_to_send);

         if (!retryResp && !dequeueEvent.scheduled())
             schedule(dequeueEvent, packetQueue.back().tick);
     } else {
         pendingDelete.reset(pkt);
     }

     return true;
 }

 void
 CfiMemory::release()
 {
     assert(isBusy);
     isBusy = false;
     if (retryReq) {
         retryReq = false;
         port.sendRetryReq();
     }
 }

 void
 CfiMemory::dequeue()
 {
     assert(!packetQueue.empty());
     DeferredPacket deferred_pkt = packetQueue.front();

     retryResp = !port.sendTimingResp(deferred_pkt.pkt);

     if (!retryResp) {
         packetQueue.pop_front();

         // if the queue is not empty, schedule the next dequeue event,
         // otherwise signal that we are drained if we were asked to do so
         if (!packetQueue.empty()) {
             // if there were packets that got in-between then we
             // already have an event scheduled, so use re-schedule
             reschedule(dequeueEvent,
                        std::max(packetQueue.front().tick, curTick()), true);
         } else if (drainState() == DrainState::Draining) {
             DPRINTF(Drain, "Draining of CfiMemory complete\n");
             signalDrainDone();
         }
     }
 }

 Tick
 CfiMemory::getLatency() const
 {
     return latency +
         (latency_var ? random_mt.random<Tick>(0, latency_var) : 0);
 }

 void
 CfiMemory::recvRespRetry()
 {
     assert(retryResp);

     dequeue();
 }

 Port &
 CfiMemory::getPort(const std::string &if_name, PortID idx)
 {
     if (if_name != "port") {
         return AbstractMemory::getPort(if_name, idx);
     } else {
         return port;
     }
 }

 DrainState
 CfiMemory::drain()
 {
     if (!packetQueue.empty()) {
         DPRINTF(Drain, "CfiMemory Queue has requests, waiting to drain\n");
         return DrainState::Draining;
     } else {
         return DrainState::Drained;
     }
 }

 void
 CfiMemory::serialize(CheckpointOut &cp) const
 {
     SERIALIZE_ENUM(readState);
     SERIALIZE_ENUM(writeState);

     SERIALIZE_SCALAR(statusRegister);

     SERIALIZE_OBJ(blocks);
     SERIALIZE_OBJ(programBuffer);
 }

 void
 CfiMemory::unserialize(CheckpointIn &cp)
 {
     UNSERIALIZE_ENUM(readState);
     UNSERIALIZE_ENUM(writeState);

     UNSERIALIZE_SCALAR(statusRegister);

     UNSERIALIZE_OBJ(blocks);
     UNSERIALIZE_OBJ(programBuffer);
 }

 CfiMemory::MemoryPort::MemoryPort(const std::string& _name,
                                      CfiMemory& _memory)
     : ResponsePort(_name, &_memory), mem(_memory)
 { }

 AddrRangeList
 CfiMemory::MemoryPort::getAddrRanges() const
 {
     AddrRangeList ranges;
     ranges.push_back(mem.getAddrRange());
     return ranges;
 }

 Tick
 CfiMemory::MemoryPort::recvAtomic(PacketPtr pkt)
 {
     return mem.recvAtomic(pkt);
 }

 Tick
 CfiMemory::MemoryPort::recvAtomicBackdoor(
         PacketPtr pkt, MemBackdoorPtr &_backdoor)
 {
     return mem.recvAtomicBackdoor(pkt, _backdoor);
 }

 void
 CfiMemory::MemoryPort::recvFunctional(PacketPtr pkt)
 {
     mem.recvFunctional(pkt);
 }

 bool
 CfiMemory::MemoryPort::recvTimingReq(PacketPtr pkt)
 {
     return mem.recvTimingReq(pkt);
 }

 void
 CfiMemory::MemoryPort::recvRespRetry()
 {
     mem.recvRespRetry();
 }

 void
 CfiMemory::cfiAccess(PacketPtr pkt)
 {
     if (pkt->isWrite()) {
         write(pkt);
     } else {
         read(pkt);
     }
 }

 void
 CfiMemory::write(PacketPtr pkt)
 {
     DPRINTF(CFI, "write, address: %#x, val: %#x\n", pkt->getAddr(),
         pkt->getUintX(ByteOrder::little));

     const Addr flash_address = pkt->getAddr() - start();

     const uint16_t value = pkt->getUintX(ByteOrder::little) & 0xffff;
     const auto new_cmd = static_cast<CfiCommand>(value & 0xff);

     switch (writeState) {
         case CfiCommand::NO_CMD:
           handleCommand(new_cmd);
           break;

         case CfiCommand::ERASE_BLOCK_SETUP:
           if (new_cmd == CfiCommand::BLOCK_ERASE_CONFIRM) {
               // Erasing the block
               // Check if block is locked
               if (blocks.isLocked(flash_address)) {
                   statusRegister |= STATUS_LOCK_ERROR;
               } else {
                   blocks.erase(pkt);
               }
           } else {
               statusRegister |= STATUS_ERASE_ERROR;
           }
           writeState = CfiCommand::NO_CMD;
           readState = CfiCommand::READ_STATUS_REG;
           break;

         case CfiCommand::LOCK_BLOCK_SETUP:
           if (new_cmd == CfiCommand::LOCK_BLOCK) {

               // Lock the addressed block
               blocks.lock(flash_address);
               readState = CfiCommand::READ_STATUS_REG;

           } else if (new_cmd == CfiCommand::UNLOCK_BLOCK) {

               // Unlock the addressed block
               blocks.unlock(flash_address);
               readState = CfiCommand::READ_STATUS_REG;

           } else {
               statusRegister |= STATUS_ERASE_ERROR;
           }

           writeState = CfiCommand::NO_CMD;
           break;

         case CfiCommand::WORD_PROGRAM:
           readState = CfiCommand::READ_STATUS_REG;
           writeState = CfiCommand::NO_CMD;

           if (blocks.isLocked(flash_address)) {
               statusRegister |= STATUS_LOCK_ERROR;
           } else {
               AbstractMemory::access(pkt);
               return;
           }
           break;

         case CfiCommand::BUFFERED_PROGRAM_SETUP: {
           // Buffer size in bytes
           auto buffer_size = (value + 1) * sizeof(uint32_t);

           // Clearing the program buffer
           programBuffer.setup(buffer_size);

           readState = CfiCommand::READ_STATUS_REG;
           writeState = CfiCommand::BUFFER_SIZE_READ;
           break;
         }

         case CfiCommand::BUFFER_SIZE_READ: {
           // Write to the buffer and check if a writeback is needed
           // (if the buffer is full)
           auto writeback = programBuffer.write(
               flash_address, pkt->getPtr<void>(), pkt->getSize());

           if (writeback) {
               if (new_cmd == CfiCommand::BUFFERED_PROGRAM_CONFIRM) {
                   auto success = programBuffer.writeback();
                   if (!success)
                       statusRegister |= STATUS_LOCK_ERROR;

                   readState = CfiCommand::READ_STATUS_REG;
               } else {
                   statusRegister |= STATUS_PROGRAM_LOCK_BIT;
               }
               writeState = CfiCommand::NO_CMD;
           }
           break;
         }

         default:
           panic("Invalid Write State\n");
           return;
     }

     pkt->makeResponse();
 }

 void
 CfiMemory::read(PacketPtr pkt)
 {
     const Addr flash_address = pkt->getAddr() - start();
     uint64_t value = 0;

     switch (readState) {
       case CfiCommand::READ_STATUS_REG:
         value = statusRegister;
         break;
       case CfiCommand::READ_DEVICE_ID:
         value = readDeviceID(flash_address);
         break;
       case CfiCommand::READ_CFI_QUERY:
         value = cfiQuery(flash_address);
         break;
       case CfiCommand::READ_ARRAY:
         AbstractMemory::access(pkt);
         return;
       default:
         panic("Invalid Read State\n");
         return;
     }

     if (numberOfChips == 2) {
         value |= (value << 16);
     }

     pkt->setUintX(value, ByteOrder::little);
     pkt->makeResponse();

     DPRINTF(CFI, "read, address: %#x, val: %#x\n", pkt->getAddr(),
         pkt->getUintX(ByteOrder::little));

 }

 uint64_t
 CfiMemory::readDeviceID(Addr flash_address) const
 {
     switch ((flash_address & 0xff) / bankWidth) {
       case 0x00: // vendor ID
         return vendorID;
       case 0x01: // device ID
         return deviceID;
       case 0x02: // lock bit
         return blocks.isLocked(flash_address);
       default:
         // Unsupported entries
         warn("Invalid Device Identifier code: %d\n", flash_address & 0xff);
         return 0;
     }
 }

 void
 CfiMemory::handleCommand(CfiCommand new_cmd)
 {
     switch (new_cmd) {
       case CfiCommand::READ_ARRAY:
         DPRINTF(CFI, "CFI Command: Read Array\n");
         readState = CfiCommand::READ_ARRAY;
         break;
       case CfiCommand::READ_DEVICE_ID:
         DPRINTF(CFI, "CFI Command: Read Device Identifier\n");
         readState = CfiCommand::READ_DEVICE_ID;
         break;
      case CfiCommand::READ_CFI_QUERY:
         DPRINTF(CFI, "CFI Command: CFI Query\n");
         readState = CfiCommand::READ_CFI_QUERY;
         break;
       case CfiCommand::READ_STATUS_REG:
         DPRINTF(CFI, "CFI Command: Read Status Register\n");
         readState = CfiCommand::READ_STATUS_REG;
         break;
       case CfiCommand::CLEAR_STATUS_REG:
         DPRINTF(CFI, "CFI Command: Clear Status Register\n");
         statusRegister = STATUS_READY;
         break;
       case CfiCommand::BUFFERED_PROGRAM_CONFIRM:
         DPRINTF(CFI, "CFI Command: Buffered Program Confirm\n");
         break;
       case CfiCommand::ERASE_BLOCK_SETUP:
         DPRINTF(CFI, "CFI Command: Erase Block Setup\n");
         writeState = CfiCommand::ERASE_BLOCK_SETUP;
         readState = CfiCommand::READ_STATUS_REG;
         break;
       case CfiCommand::LOCK_BLOCK_SETUP:
         DPRINTF(CFI, "CFI Command: Lock Block Setup\n");
         writeState = CfiCommand::LOCK_BLOCK_SETUP;
         break;
       case CfiCommand::WORD_PROGRAM:
         DPRINTF(CFI, "CFI Command: Word Program\n");
         writeState = CfiCommand::WORD_PROGRAM;
         readState = CfiCommand::READ_STATUS_REG;
         break;
       case CfiCommand::BUFFERED_PROGRAM_SETUP:
         DPRINTF(CFI, "CFI Command: Buffered Program Setup\n");
         writeState = CfiCommand::BUFFERED_PROGRAM_SETUP;
         readState = CfiCommand::READ_STATUS_REG;
         break;
       default:
         panic("Don't know what to do with %#x\n",
             static_cast<uint16_t>(new_cmd));
     }

 }

 uint64_t
 CfiMemory::cfiQuery(Addr flash_address)
 {
     flash_address /= bankWidth;

     panic_if(flash_address >= sizeof(cfiQueryTable),
         "Acessing invalid entry in CFI query table (addr=%#x)",
         flash_address);

     return cfiQueryTable[flash_address];
 }

 void
 CfiMemory::BlockData::erase(PacketPtr pkt)
 {
     auto host_address = parent.toHostAddr(pkt->getAddr());
     std::memset(host_address, 0xff, blockSize);
 }

 } // namespace memory
 } // namespace gem5
	/*
	* Copyright (c) 2010-2013, 2015, 2021 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) 2001-2005 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 "mem/cfi_mem.hh"

	#include <cmath>

	#include "base/intmath.hh"
	#include "base/random.hh"
	#include "base/trace.hh"
	#include "debug/CFI.hh"
	#include "debug/Drain.hh"

	namespace gem5
	{

	namespace memory
	{

	bool
	CfiMemory::BlockData::isLocked(Addr block_address) const
	{
	return locked[blockIdx(block_address)];
	}

	void
	CfiMemory::BlockData::lock(Addr block_address)
	{
	locked[blockIdx(block_address)] = true;
	}

	void
	CfiMemory::BlockData::unlock(Addr block_address)
	{
	locked[blockIdx(block_address)] = false;
	}

	void
	CfiMemory::BlockData::serialize(CheckpointOut &cp) const
	{
	SERIALIZE_CONTAINER(locked);
	}

	void
	CfiMemory::BlockData::unserialize(CheckpointIn &cp)
	{
	UNSERIALIZE_CONTAINER(locked);
	}

	uint32_t
	CfiMemory::BlockData::blockIdx(Addr block_address) const
	{
	return block_address / blockSize;
	}

	void
	CfiMemory::ProgramBuffer::setup(ssize_t buffer_size)
	{
	/** Clipping the size to its limit */
	if (buffer_size > MAX_BUFFER_SIZE) {
	buffer_size = MAX_BUFFER_SIZE;
	}

	buffer.resize(buffer_size);
	std::fill(buffer.begin(), buffer.end(), 0);
	bytesWritten = 0;
	}

	bool
	CfiMemory::ProgramBuffer::write(Addr flash_address,
	void *data_ptr, ssize_t size)
	{
	if (bytesWritten >= buffer.size())
	return true;

	if (bytesWritten == 0) {
	blockPointer = flash_address;
	}

	const Addr offset = flash_address - blockPointer;

	if (flash_address < blockPointer \|\| offset >= MAX_BUFFER_SIZE)
	return true;

	std::memcpy(buffer.data() + offset, data_ptr, size);
	bytesWritten += size;

	return false;
	}

	bool
	CfiMemory::ProgramBuffer::writeback()
	{
	if (parent.blocks.isLocked(blockPointer)) {
	return false;
	} else {
	std::memcpy(parent.toHostAddr(parent.start() + blockPointer),
	buffer.data(), bytesWritten);
	return true;
	}
	}

	void
	CfiMemory::ProgramBuffer::serialize(CheckpointOut &cp) const
	{
	SERIALIZE_CONTAINER(buffer);
	SERIALIZE_SCALAR(bytesWritten);
	SERIALIZE_SCALAR(blockPointer);
	}

	void
	CfiMemory::ProgramBuffer::unserialize(CheckpointIn &cp)
	{
	UNSERIALIZE_CONTAINER(buffer);
	UNSERIALIZE_SCALAR(bytesWritten);
	UNSERIALIZE_SCALAR(blockPointer);
	}

	CfiMemory::CfiMemory(const CfiMemoryParams &p)
	: AbstractMemory(p),
	port(name() + ".port", *this), latency(p.latency),
	latency_var(p.latency_var), bandwidth(p.bandwidth), isBusy(false),
	retryReq(false), retryResp(false),
	releaseEvent([this]{ release(); }, name()),
	dequeueEvent([this]{ dequeue(); }, name()),
	numberOfChips(2),
	vendorID(p.vendor_id),
	deviceID(p.device_id),
	bankWidth(p.bank_width),
	readState(CfiCommand::READ_ARRAY), writeState(CfiCommand::NO_CMD),
	statusRegister(STATUS_READY),
	blocks(*this, size() / p.blk_size, p.blk_size),
	programBuffer(*this),
	cfiQueryTable{
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	/* Query-unique ASCII string */
	'Q', 'R', 'Y',
	/* Primary Algorithm Command Set and Control = Intel/Sharp */
	0x01, 0x00,
	/* Address for Primary Algorithm extended Query */
	0x31, 0x00,
	/* Alternative Algorithm Command Set and Control Interface */
	0x00, 0x00,
	/* Address for Alternative Algorithm extended Query */
	0x00, 0x00,
	/* Vcc Minimum Program/Erase or Write voltage ([7:4].[3-0]V) */
	0x45,
	/* Vcc Maximum Program/Erase or Write voltage ([7:4].[3-0]V) */
	0x55,
	/* Vpp Minimum Program/Erase voltage (0 = No Vpp pin) */
	0x00,
	/* Vpp Minimum Program/Erase voltage (0 = No Vpp pin) */
	0x00,
	/* Typical timeout per single byte/word/D-word program: (2^N us) */
	0x01,
	/* Typical timeout for maximum-size multi-byte program: (2^N us) */
	0x01,
	/* Typical timeout per individual block erase: (2^N ms) */
	0x01,
	/* Typical timeout for full chip erase: (2^N ms) */
	0x00,
	/* Maximum timeout for byte/word/D-word program (2^N typical) */
	0x00,
	/* Maximum timeout for multi-byte program (2^N typical) */
	0x00,
	/* Maximum timeout per individual block erase (2^N typical) */
	0x00,
	/* Maximum timeout for chip erase (2^N typical) */
	0x00,
	/* Device Size in number of bytes (2^N) */
	static_cast<uint8_t>(log2(size())),
	/* Flash Device Interface Code description */
	0x05, 0x00,
	/* Maximum number of bytes in multi-byte program (2^N) */
	static_cast<uint8_t>(bits(log2i(ProgramBuffer::MAX_BUFFER_SIZE), 7, 0)),
	static_cast<uint8_t>(bits(log2i(ProgramBuffer::MAX_BUFFER_SIZE), 15, 8)),
	/* Number of Erase Block Regions within device */
	0x01,
	/* Erase Block Region Information */
	static_cast<uint8_t>(bits(blocks.number(), 7, 0)),
	static_cast<uint8_t>(bits(blocks.number(), 15, 8)),
	static_cast<uint8_t>(bits(blocks.size(), 7, 0)),
	static_cast<uint8_t>(bits(blocks.size(), 15, 8)),
	}
	{}

	void
	CfiMemory::init()
	{
	AbstractMemory::init();

	// allow unconnected memories as this is used in several ruby
	// systems at the moment
	if (port.isConnected()) {
	port.sendRangeChange();
	}
	}

	Tick
	CfiMemory::recvAtomic(PacketPtr pkt)
	{
	panic_if(pkt->cacheResponding(), "Should not see packets where cache "
	"is responding");

	cfiAccess(pkt);
	return getLatency();
	}

	Tick
	CfiMemory::recvAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &_backdoor)
	{
	Tick latency = recvAtomic(pkt);

	if (backdoor.ptr())
	_backdoor = &backdoor;
	return latency;
	}

	void
	CfiMemory::recvFunctional(PacketPtr pkt)
	{
	pkt->pushLabel(name());

	functionalAccess(pkt);

	bool done = false;
	auto p = packetQueue.begin();
	// potentially update the packets in our packet queue as well
	while (!done && p != packetQueue.end()) {
	done = pkt->trySatisfyFunctional(p->pkt);
	++p;
	}

	pkt->popLabel();
	}

	bool
	CfiMemory::recvTimingReq(PacketPtr pkt)
	{
	panic_if(pkt->cacheResponding(), "Should not see packets where cache "
	"is responding");

	panic_if(!(pkt->isRead() \|\| pkt->isWrite()),
	"Should only see read and writes at memory controller, "
	"saw %s to %#llx\n", pkt->cmdString(), pkt->getAddr());

	// we should not get a new request after committing to retry the
	// current one, but unfortunately the CPU violates this rule, so
	// simply ignore it for now
	if (retryReq)
	return false;

	// if we are busy with a read or write, remember that we have to
	// retry
	if (isBusy) {
	retryReq = true;
	return false;
	}

	// technically the packet only reaches us after the header delay,
	// and since this is a memory controller we also need to
	// deserialise the payload before performing any write operation
	Tick receive_delay = pkt->headerDelay + pkt->payloadDelay;
	pkt->headerDelay = pkt->payloadDelay = 0;

	// update the release time according to the bandwidth limit, and
	// do so with respect to the time it takes to finish this request
	// rather than long term as it is the short term data rate that is
	// limited for any real memory

	// calculate an appropriate tick to release to not exceed
	// the bandwidth limit
	Tick duration = pkt->getSize() * bandwidth;

	// only consider ourselves busy if there is any need to wait
	// to avoid extra events being scheduled for (infinitely) fast
	// memories
	if (duration != 0) {
	schedule(releaseEvent, curTick() + duration);
	isBusy = true;
	}

	// go ahead and deal with the packet and put the response in the
	// queue if there is one
	bool needs_response = pkt->needsResponse();
	recvAtomic(pkt);
	// turn packet around to go back to requester if response expected
	if (needs_response) {
	// recvAtomic() should already have turned packet into
	// atomic response
	assert(pkt->isResponse());

	Tick when_to_send = curTick() + receive_delay + getLatency();

	// typically this should be added at the end, so start the
	// insertion sort with the last element, also make sure not to
	// re-order in front of some existing packet with the same
	// address, the latter is important as this memory effectively
	// hands out exclusive copies (shared is not asserted)
	auto i = packetQueue.end();
	--i;
	while (i != packetQueue.begin() && when_to_send < i->tick &&
	!i->pkt->matchAddr(pkt)) {
	--i;
	}

	// emplace inserts the element before the position pointed to by
	// the iterator, so advance it one step
	packetQueue.emplace(++i, pkt, when_to_send);

	if (!retryResp && !dequeueEvent.scheduled())
	schedule(dequeueEvent, packetQueue.back().tick);
	} else {
	pendingDelete.reset(pkt);
	}

	return true;
	}

	void
	CfiMemory::release()
	{
	assert(isBusy);
	isBusy = false;
	if (retryReq) {
	retryReq = false;
	port.sendRetryReq();
	}
	}

	void
	CfiMemory::dequeue()
	{
	assert(!packetQueue.empty());
	DeferredPacket deferred_pkt = packetQueue.front();

	retryResp = !port.sendTimingResp(deferred_pkt.pkt);

	if (!retryResp) {
	packetQueue.pop_front();

	// if the queue is not empty, schedule the next dequeue event,
	// otherwise signal that we are drained if we were asked to do so
	if (!packetQueue.empty()) {
	// if there were packets that got in-between then we
	// already have an event scheduled, so use re-schedule
	reschedule(dequeueEvent,
	std::max(packetQueue.front().tick, curTick()), true);
	} else if (drainState() == DrainState::Draining) {
	DPRINTF(Drain, "Draining of CfiMemory complete\n");
	signalDrainDone();
	}
	}
	}

	Tick
	CfiMemory::getLatency() const
	{
	return latency +
	(latency_var ? random_mt.random<Tick>(0, latency_var) : 0);
	}

	void
	CfiMemory::recvRespRetry()
	{
	assert(retryResp);

	dequeue();
	}

	Port &
	CfiMemory::getPort(const std::string &if_name, PortID idx)
	{
	if (if_name != "port") {
	return AbstractMemory::getPort(if_name, idx);
	} else {
	return port;
	}
	}

	DrainState
	CfiMemory::drain()
	{
	if (!packetQueue.empty()) {
	DPRINTF(Drain, "CfiMemory Queue has requests, waiting to drain\n");
	return DrainState::Draining;
	} else {
	return DrainState::Drained;
	}
	}

	void
	CfiMemory::serialize(CheckpointOut &cp) const
	{
	SERIALIZE_ENUM(readState);
	SERIALIZE_ENUM(writeState);

	SERIALIZE_SCALAR(statusRegister);

	SERIALIZE_OBJ(blocks);
	SERIALIZE_OBJ(programBuffer);
	}

	void
	CfiMemory::unserialize(CheckpointIn &cp)
	{
	UNSERIALIZE_ENUM(readState);
	UNSERIALIZE_ENUM(writeState);

	UNSERIALIZE_SCALAR(statusRegister);

	UNSERIALIZE_OBJ(blocks);
	UNSERIALIZE_OBJ(programBuffer);
	}

	CfiMemory::MemoryPort::MemoryPort(const std::string& _name,
	CfiMemory& _memory)
	: ResponsePort(_name, &_memory), mem(_memory)
	{ }

	AddrRangeList
	CfiMemory::MemoryPort::getAddrRanges() const
	{
	AddrRangeList ranges;
	ranges.push_back(mem.getAddrRange());
	return ranges;
	}

	Tick
	CfiMemory::MemoryPort::recvAtomic(PacketPtr pkt)
	{
	return mem.recvAtomic(pkt);
	}

	Tick
	CfiMemory::MemoryPort::recvAtomicBackdoor(
	PacketPtr pkt, MemBackdoorPtr &_backdoor)
	{
	return mem.recvAtomicBackdoor(pkt, _backdoor);
	}

	void
	CfiMemory::MemoryPort::recvFunctional(PacketPtr pkt)
	{
	mem.recvFunctional(pkt);
	}

	bool
	CfiMemory::MemoryPort::recvTimingReq(PacketPtr pkt)
	{
	return mem.recvTimingReq(pkt);
	}

	void
	CfiMemory::MemoryPort::recvRespRetry()
	{
	mem.recvRespRetry();
	}

	void
	CfiMemory::cfiAccess(PacketPtr pkt)
	{
	if (pkt->isWrite()) {
	write(pkt);
	} else {
	read(pkt);
	}
	}

	void
	CfiMemory::write(PacketPtr pkt)
	{
	DPRINTF(CFI, "write, address: %#x, val: %#x\n", pkt->getAddr(),
	pkt->getUintX(ByteOrder::little));

	const Addr flash_address = pkt->getAddr() - start();

	const uint16_t value = pkt->getUintX(ByteOrder::little) & 0xffff;
	const auto new_cmd = static_cast<CfiCommand>(value & 0xff);

	switch (writeState) {
	case CfiCommand::NO_CMD:
	handleCommand(new_cmd);
	break;

	case CfiCommand::ERASE_BLOCK_SETUP:
	if (new_cmd == CfiCommand::BLOCK_ERASE_CONFIRM) {
	// Erasing the block
	// Check if block is locked
	if (blocks.isLocked(flash_address)) {
	statusRegister \|= STATUS_LOCK_ERROR;
	} else {
	blocks.erase(pkt);
	}
	} else {
	statusRegister \|= STATUS_ERASE_ERROR;
	}
	writeState = CfiCommand::NO_CMD;
	readState = CfiCommand::READ_STATUS_REG;
	break;

	case CfiCommand::LOCK_BLOCK_SETUP:
	if (new_cmd == CfiCommand::LOCK_BLOCK) {

	// Lock the addressed block
	blocks.lock(flash_address);
	readState = CfiCommand::READ_STATUS_REG;

	} else if (new_cmd == CfiCommand::UNLOCK_BLOCK) {

	// Unlock the addressed block
	blocks.unlock(flash_address);
	readState = CfiCommand::READ_STATUS_REG;

	} else {
	statusRegister \|= STATUS_ERASE_ERROR;
	}

	writeState = CfiCommand::NO_CMD;
	break;

	case CfiCommand::WORD_PROGRAM:
	readState = CfiCommand::READ_STATUS_REG;
	writeState = CfiCommand::NO_CMD;

	if (blocks.isLocked(flash_address)) {
	statusRegister \|= STATUS_LOCK_ERROR;
	} else {
	AbstractMemory::access(pkt);
	return;
	}
	break;

	case CfiCommand::BUFFERED_PROGRAM_SETUP: {
	// Buffer size in bytes
	auto buffer_size = (value + 1) * sizeof(uint32_t);

	// Clearing the program buffer
	programBuffer.setup(buffer_size);

	readState = CfiCommand::READ_STATUS_REG;
	writeState = CfiCommand::BUFFER_SIZE_READ;
	break;
	}

	case CfiCommand::BUFFER_SIZE_READ: {
	// Write to the buffer and check if a writeback is needed
	// (if the buffer is full)
	auto writeback = programBuffer.write(
	flash_address, pkt->getPtr<void>(), pkt->getSize());

	if (writeback) {
	if (new_cmd == CfiCommand::BUFFERED_PROGRAM_CONFIRM) {
	auto success = programBuffer.writeback();
	if (!success)
	statusRegister \|= STATUS_LOCK_ERROR;

	readState = CfiCommand::READ_STATUS_REG;
	} else {
	statusRegister \|= STATUS_PROGRAM_LOCK_BIT;
	}
	writeState = CfiCommand::NO_CMD;
	}
	break;
	}

	default:
	panic("Invalid Write State\n");
	return;
	}

	pkt->makeResponse();
	}

	void
	CfiMemory::read(PacketPtr pkt)
	{
	const Addr flash_address = pkt->getAddr() - start();
	uint64_t value = 0;

	switch (readState) {
	case CfiCommand::READ_STATUS_REG:
	value = statusRegister;
	break;
	case CfiCommand::READ_DEVICE_ID:
	value = readDeviceID(flash_address);
	break;
	case CfiCommand::READ_CFI_QUERY:
	value = cfiQuery(flash_address);
	break;
	case CfiCommand::READ_ARRAY:
	AbstractMemory::access(pkt);
	return;
	default:
	panic("Invalid Read State\n");
	return;
	}

	if (numberOfChips == 2) {
	value \|= (value << 16);
	}

	pkt->setUintX(value, ByteOrder::little);
	pkt->makeResponse();

	DPRINTF(CFI, "read, address: %#x, val: %#x\n", pkt->getAddr(),
	pkt->getUintX(ByteOrder::little));

	}

	uint64_t
	CfiMemory::readDeviceID(Addr flash_address) const
	{
	switch ((flash_address & 0xff) / bankWidth) {
	case 0x00: // vendor ID
	return vendorID;
	case 0x01: // device ID
	return deviceID;
	case 0x02: // lock bit
	return blocks.isLocked(flash_address);
	default:
	// Unsupported entries
	warn("Invalid Device Identifier code: %d\n", flash_address & 0xff);
	return 0;
	}
	}

	void
	CfiMemory::handleCommand(CfiCommand new_cmd)
	{
	switch (new_cmd) {
	case CfiCommand::READ_ARRAY:
	DPRINTF(CFI, "CFI Command: Read Array\n");
	readState = CfiCommand::READ_ARRAY;
	break;
	case CfiCommand::READ_DEVICE_ID:
	DPRINTF(CFI, "CFI Command: Read Device Identifier\n");
	readState = CfiCommand::READ_DEVICE_ID;
	break;
	case CfiCommand::READ_CFI_QUERY:
	DPRINTF(CFI, "CFI Command: CFI Query\n");
	readState = CfiCommand::READ_CFI_QUERY;
	break;
	case CfiCommand::READ_STATUS_REG:
	DPRINTF(CFI, "CFI Command: Read Status Register\n");
	readState = CfiCommand::READ_STATUS_REG;
	break;
	case CfiCommand::CLEAR_STATUS_REG:
	DPRINTF(CFI, "CFI Command: Clear Status Register\n");
	statusRegister = STATUS_READY;
	break;
	case CfiCommand::BUFFERED_PROGRAM_CONFIRM:
	DPRINTF(CFI, "CFI Command: Buffered Program Confirm\n");
	break;
	case CfiCommand::ERASE_BLOCK_SETUP:
	DPRINTF(CFI, "CFI Command: Erase Block Setup\n");
	writeState = CfiCommand::ERASE_BLOCK_SETUP;
	readState = CfiCommand::READ_STATUS_REG;
	break;
	case CfiCommand::LOCK_BLOCK_SETUP:
	DPRINTF(CFI, "CFI Command: Lock Block Setup\n");
	writeState = CfiCommand::LOCK_BLOCK_SETUP;
	break;
	case CfiCommand::WORD_PROGRAM:
	DPRINTF(CFI, "CFI Command: Word Program\n");
	writeState = CfiCommand::WORD_PROGRAM;
	readState = CfiCommand::READ_STATUS_REG;
	break;
	case CfiCommand::BUFFERED_PROGRAM_SETUP:
	DPRINTF(CFI, "CFI Command: Buffered Program Setup\n");
	writeState = CfiCommand::BUFFERED_PROGRAM_SETUP;
	readState = CfiCommand::READ_STATUS_REG;
	break;
	default:
	panic("Don't know what to do with %#x\n",
	static_cast<uint16_t>(new_cmd));
	}

	}

	uint64_t
	CfiMemory::cfiQuery(Addr flash_address)
	{
	flash_address /= bankWidth;

	panic_if(flash_address >= sizeof(cfiQueryTable),
	"Acessing invalid entry in CFI query table (addr=%#x)",
	flash_address);

	return cfiQueryTable[flash_address];
	}

	void
	CfiMemory::BlockData::erase(PacketPtr pkt)
	{
	auto host_address = parent.toHostAddr(pkt->getAddr());
	std::memset(host_address, 0xff, blockSize);
	}

	} // namespace memory
	} // namespace gem5