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/*
* Copyright (c) 2012-2018 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) 2002-2005 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.
*
* Authors: Erik Hallnor
* Dave Greene
* Steve Reinhardt
* Ron Dreslinski
* Andreas Hansson
*/
/**
* @file
* Describes a cache
*/
#ifndef __MEM_CACHE_CACHE_HH__
#define __MEM_CACHE_CACHE_HH__
#include <cstdint>
#include <unordered_set>
#include "base/types.hh"
#include "mem/cache/base.hh"
#include "mem/packet.hh"
class CacheBlk;
struct CacheParams;
class MSHR;
/**
* A coherent cache that can be arranged in flexible topologies.
*/
class Cache : public BaseCache
{
protected:
/**
* This cache should allocate a block on a line-sized write miss.
*/
const bool doFastWrites;
/**
* Store the outstanding requests that we are expecting snoop
* responses from so we can determine which snoop responses we
* generated and which ones were merely forwarded.
*/
std::unordered_set<RequestPtr> outstandingSnoop;
protected:
/**
* Turn line-sized writes into WriteInvalidate transactions.
*/
void promoteWholeLineWrites(PacketPtr pkt);
bool access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
PacketList &writebacks) override;
void handleTimingReqHit(PacketPtr pkt, CacheBlk *blk,
Tick request_time) override;
void handleTimingReqMiss(PacketPtr pkt, CacheBlk *blk,
Tick forward_time,
Tick request_time) override;
void recvTimingReq(PacketPtr pkt) override;
void doWritebacks(PacketList& writebacks, Tick forward_time) override;
void doWritebacksAtomic(PacketList& writebacks) override;
void serviceMSHRTargets(MSHR *mshr, const PacketPtr pkt, CacheBlk *blk,
PacketList& writebacks) override;
void recvTimingSnoopReq(PacketPtr pkt) override;
void recvTimingSnoopResp(PacketPtr pkt) override;
Cycles handleAtomicReqMiss(PacketPtr pkt, CacheBlk *&blk,
PacketList &writebacks) override;
Tick recvAtomic(PacketPtr pkt) override;
Tick recvAtomicSnoop(PacketPtr pkt) override;
void satisfyRequest(PacketPtr pkt, CacheBlk *blk,
bool deferred_response = false,
bool pending_downgrade = false) override;
void doTimingSupplyResponse(PacketPtr req_pkt, const uint8_t *blk_data,
bool already_copied, bool pending_inval);
/**
* Perform an upward snoop if needed, and update the block state
* (possibly invalidating the block). Also create a response if required.
*
* @param pkt Snoop packet
* @param blk Cache block being snooped
* @param is_timing Timing or atomic for the response
* @param is_deferred Is this a deferred snoop or not?
* @param pending_inval Do we have a pending invalidation?
*
* @return The snoop delay incurred by the upwards snoop
*/
uint32_t handleSnoop(PacketPtr pkt, CacheBlk *blk,
bool is_timing, bool is_deferred, bool pending_inval);
M5_NODISCARD PacketPtr evictBlock(CacheBlk *blk) override;
void evictBlock(CacheBlk *blk, PacketList &writebacks) override;
/**
* Create a CleanEvict request for the given block.
*
* @param blk The block to evict.
* @return The CleanEvict request for the block.
*/
PacketPtr cleanEvictBlk(CacheBlk *blk);
PacketPtr createMissPacket(PacketPtr cpu_pkt, CacheBlk *blk,
bool needsWritable) const override;
/**
* Send up a snoop request and find cached copies. If cached copies are
* found, set the BLOCK_CACHED flag in pkt.
*/
bool isCachedAbove(PacketPtr pkt, bool is_timing = true);
public:
/** Instantiates a basic cache object. */
Cache(const CacheParams *p);
/**
* Take an MSHR, turn it into a suitable downstream packet, and
* send it out. This construct allows a queue entry to choose a suitable
* approach based on its type.
*
* @param mshr The MSHR to turn into a packet and send
* @return True if the port is waiting for a retry
*/
bool sendMSHRQueuePacket(MSHR* mshr) override;
};
#endif // __MEM_CACHE_CACHE_HH__
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