packet.hh revision 2549
1/* 2 * Copyright (c) 2003 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29/** 30 * @file 31 * Declaration of the Packet Class, a packet is a transaction occuring 32 * between a single level of the memory heirarchy (ie L1->L2). 33 */ 34 35#ifndef __MEM_PACKET_HH__ 36#define __MEM_PACKET_HH__ 37 38#include "mem/request.hh" 39#include "arch/isa_traits.hh" 40#include "sim/root.hh" 41 42struct Packet; 43typedef Packet* PacketPtr; 44typedef uint8_t* PacketDataPtr; 45 46/** List of all commands associated with a packet. */ 47enum Command 48{ 49 Read, 50 Write 51}; 52 53/** The result of a particular pakets request. */ 54enum PacketResult 55{ 56 Success, 57 BadAddress, 58 Unknown 59}; 60 61class SenderState{}; 62class Coherence{}; 63 64/** 65 * A Packet is the structure to handle requests between two levels 66 * of the memory system. The Request is a global object that trancends 67 * all of the memory heirarchy, but at each levels interface a packet 68 * is created to transfer data/requests. For example, a request would 69 * be used to initiate a request to go to memory/IOdevices, as the request 70 * passes through the memory system several packets will be created. One 71 * will be created to go between the L1 and L2 caches and another to go to 72 * the next level and so forth. 73 * 74 * Packets are assumed to be returned in the case of a single response. If 75 * the transaction has no response, then the consumer will delete the packet. 76 */ 77struct Packet 78{ 79 /** The address of the request, could be virtual or physical (depending on 80 cache configurations). */ 81 Addr addr; 82 83 /** Flag structure to hold flags for this particular packet */ 84 uint64_t flags; 85 86 /** A pointer to the overall request. */ 87 RequestPtr req; 88 89 /** A virtual base opaque structure used to hold 90 coherence status messages. */ 91 Coherence *coherence; // virtual base opaque, 92 // assert(dynamic_cast<Foo>) etc. 93 94 /** A virtual base opaque structure used to hold the senders state. */ 95 SenderState *senderState; // virtual base opaque, 96 // assert(dynamic_cast<Foo>) etc. 97 98 /** A pointer to the data being transfered. It can be differnt sizes 99 at each level of the heirarchy so it belongs in the packet, 100 not request. 101 This pointer may be NULL! If it isn't null when received by the producer 102 of data it refers to memory that has not been dynamically allocated. 103 Otherwise the producer should simply allocate dynamic memory to use. 104 */ 105 PacketDataPtr data; 106 107 /** Indicates the size of the request. */ 108 int size; 109 110 /** A index of the source of the transaction. */ 111 short src; 112 113 /** A index to the destination of the transaction. */ 114 short dest; 115 116 /** The command of the transaction. */ 117 Command cmd; 118 119 /** The time this request was responded to. Used to calculate latencies. */ 120 Tick time; 121 122 /** The result of the packet transaction. */ 123 PacketResult result; 124 125 /** Accessor function that returns the source index of the packet. */ 126 short getSrc() const { return src; } 127 128 /** Accessor function that returns the destination index of 129 the packet. */ 130 short getDest() const { return dest; } 131 132 Packet() 133 : result(Unknown) 134 {} 135 136 void reset() { result = Unknown; } 137}; 138 139#endif //__MEM_PACKET_HH 140