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Diffstat (limited to 'src/mem/packet.hh')
-rw-r--r-- | src/mem/packet.hh | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/src/mem/packet.hh b/src/mem/packet.hh new file mode 100644 index 000000000..403039d96 --- /dev/null +++ b/src/mem/packet.hh @@ -0,0 +1,300 @@ +/* + * Copyright (c) 2006 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: Ron Dreslinski + * Steve Reinhardt + * Ali Saidi + */ + +/** + * @file + * Declaration of the Packet class. + */ + +#ifndef __MEM_PACKET_HH__ +#define __MEM_PACKET_HH__ + +#include "mem/request.hh" +#include "arch/isa_traits.hh" +#include "sim/root.hh" + +struct Packet; +typedef Packet* PacketPtr; +typedef uint8_t* PacketDataPtr; + +/** + * A Packet is used to encapsulate a transfer between two objects in + * the memory system (e.g., the L1 and L2 cache). (In contrast, a + * single Request travels all the way from the requester to the + * ultimate destination and back, possibly being conveyed by several + * different Packets along the way.) + */ +class Packet +{ + private: + /** A pointer to the data being transfered. It can be differnt + * sizes at each level of the heirarchy so it belongs in the + * packet, not request. This may or may not be populated when a + * responder recieves the packet. If not populated it memory + * should be allocated. + */ + PacketDataPtr data; + + /** Is the data pointer set to a value that shouldn't be freed + * when the packet is destroyed? */ + bool staticData; + /** The data pointer points to a value that should be freed when + * the packet is destroyed. */ + bool dynamicData; + /** the data pointer points to an array (thus delete [] ) needs to + * be called on it rather than simply delete.*/ + bool arrayData; + + + /** The address of the request. This address could be virtual or + * physical, depending on the system configuration. */ + Addr addr; + + /** The size of the request or transfer. */ + int size; + + /** Device address (e.g., bus ID) of the source of the + * transaction. The source is not responsible for setting this + * field; it is set implicitly by the interconnect when the + * packet * is first sent. */ + short src; + + /** Device address (e.g., bus ID) of the destination of the + * transaction. The special value Broadcast indicates that the + * packet should be routed based on its address. This field is + * initialized in the constructor and is thus always valid + * (unlike * addr, size, and src). */ + short dest; + + /** Are the 'addr' and 'size' fields valid? */ + bool addrSizeValid; + /** Is the 'src' field valid? */ + bool srcValid; + + public: + + /** The special destination address indicating that the packet + * should be routed based on its address. */ + static const short Broadcast = -1; + + /** A pointer to the original request. */ + RequestPtr req; + + /** A virtual base opaque structure used to hold coherence-related + * state. A specific subclass would be derived from this to + * carry state specific to a particular coherence protocol. */ + class CoherenceState { + public: + virtual ~CoherenceState() {} + }; + + /** This packet's coherence state. Caches should use + * dynamic_cast<> to cast to the state appropriate for the + * system's coherence protocol. */ + CoherenceState *coherence; + + /** A virtual base opaque structure used to hold state associated + * with the packet but specific to the sending device (e.g., an + * MSHR). A pointer to this state is returned in the packet's + * response so that the sender can quickly look up the state + * needed to process it. A specific subclass would be derived + * from this to carry state specific to a particular sending + * device. */ + class SenderState { + public: + virtual ~SenderState() {} + }; + + /** This packet's sender state. Devices should use dynamic_cast<> + * to cast to the state appropriate to the sender. */ + SenderState *senderState; + + private: + /** List of command attributes. */ + enum CommandAttribute + { + IsRead = 1 << 0, + IsWrite = 1 << 1, + IsPrefetch = 1 << 2, + IsInvalidate = 1 << 3, + IsRequest = 1 << 4, + IsResponse = 1 << 5, + NeedsResponse = 1 << 6, + }; + + public: + /** List of all commands associated with a packet. */ + enum Command + { + ReadReq = IsRead | IsRequest | NeedsResponse, + WriteReq = IsWrite | IsRequest | NeedsResponse, + WriteReqNoAck = IsWrite | IsRequest, + ReadResp = IsRead | IsResponse, + WriteResp = IsWrite | IsResponse + }; + + /** Return the string name of the cmd field (for debugging and + * tracing). */ + const std::string &cmdString() const; + + /** The command field of the packet. */ + Command cmd; + + bool isRead() { return (cmd & IsRead) != 0; } + bool isRequest() { return (cmd & IsRequest) != 0; } + bool isResponse() { return (cmd & IsResponse) != 0; } + bool needsResponse() { return (cmd & NeedsResponse) != 0; } + + /** Possible results of a packet's request. */ + enum Result + { + Success, + BadAddress, + Nacked, + Unknown + }; + + /** The result of this packet's request. */ + Result result; + + /** Accessor function that returns the source index of the packet. */ + short getSrc() const { assert(srcValid); return src; } + void setSrc(short _src) { src = _src; srcValid = true; } + + /** Accessor function that returns the destination index of + the packet. */ + short getDest() const { return dest; } + void setDest(short _dest) { dest = _dest; } + + Addr getAddr() const { assert(addrSizeValid); return addr; } + int getSize() const { assert(addrSizeValid); return size; } + + /** Constructor. Note that a Request object must be constructed + * first, but the Requests's physical address and size fields + * need not be valid. The command and destination addresses + * must be supplied. */ + Packet(Request *_req, Command _cmd, short _dest) + : data(NULL), staticData(false), dynamicData(false), arrayData(false), + addr(_req->paddr), size(_req->size), dest(_dest), + addrSizeValid(_req->validPaddr), + srcValid(false), + req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), + result(Unknown) + { + } + + /** Destructor. */ + ~Packet() + { deleteData(); } + + /** Reinitialize packet address and size from the associated + * Request object, and reset other fields that may have been + * modified by a previous transaction. Typically called when a + * statically allocated Request/Packet pair is reused for + * multiple transactions. */ + void reinitFromRequest() { + assert(req->validPaddr); + addr = req->paddr; + size = req->size; + addrSizeValid = true; + result = Unknown; + if (dynamicData) { + deleteData(); + dynamicData = false; + arrayData = false; + } + } + + /** Take a request packet and modify it in place to be suitable + * for returning as a response to that request. Used for timing + * accesses only. For atomic and functional accesses, the + * request packet is always implicitly passed back *without* + * modifying the command or destination fields, so this function + * should not be called. */ + void makeTimingResponse() { + assert(needsResponse()); + int icmd = (int)cmd; + icmd &= ~(IsRequest | NeedsResponse); + icmd |= IsResponse; + cmd = (Command)icmd; + dest = src; + srcValid = false; + } + + /** Take a request packet that has been returned as NACKED and modify it so + * that it can be sent out again. Only packets that need a response can be + * NACKED, so verify that that is true. */ + void reinitNacked() { + assert(needsResponse() && result == Nacked); + dest = Broadcast; + result = Unknown; + } + + + /** Set the data pointer to the following value that should not be freed. */ + template <typename T> + void dataStatic(T *p); + + /** Set the data pointer to a value that should have delete [] called on it. + */ + template <typename T> + void dataDynamicArray(T *p); + + /** set the data pointer to a value that should have delete called on it. */ + template <typename T> + void dataDynamic(T *p); + + /** return the value of what is pointed to in the packet. */ + template <typename T> + T get(); + + /** get a pointer to the data ptr. */ + template <typename T> + T* getPtr(); + + /** set the value in the data pointer to v. */ + template <typename T> + void set(T v); + + /** delete the data pointed to in the data pointer. Ok to call to matter how + * data was allocted. */ + void deleteData(); + + /** If there isn't data in the packet, allocate some. */ + void allocate(); + + /** Do the packet modify the same addresses. */ + bool intersect(Packet *p); +}; + +bool fixPacket(Packet *func, Packet *timing); +#endif //__MEM_PACKET_HH |