packet.hh revision 2662
1/* 2 * Copyright (c) 2006 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. 32 */ 33 34#ifndef __MEM_PACKET_HH__ 35#define __MEM_PACKET_HH__ 36 37#include "mem/request.hh" 38#include "arch/isa_traits.hh" 39#include "sim/root.hh" 40 41struct Packet; 42typedef Packet* PacketPtr; 43typedef uint8_t* PacketDataPtr; 44 45/** 46 * A Packet is used to encapsulate a transfer between two objects in 47 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 48 * single Request travels all the way from the requester to the 49 * ultimate destination and back, possibly being conveyed by several 50 * different Packets along the way.) 51 */ 52class Packet 53{ 54 private: 55 /** A pointer to the data being transfered. It can be differnt 56 * sizes at each level of the heirarchy so it belongs in the 57 * packet, not request. This may or may not be populated when a 58 * responder recieves the packet. If not populated it memory 59 * should be allocated. 60 */ 61 PacketDataPtr data; 62 63 /** Is the data pointer set to a value that shouldn't be freed 64 * when the packet is destroyed? */ 65 bool staticData; 66 /** The data pointer points to a value that should be freed when 67 * the packet is destroyed. */ 68 bool dynamicData; 69 /** the data pointer points to an array (thus delete [] ) needs to 70 * be called on it rather than simply delete.*/ 71 bool arrayData; 72 73 74 /** The address of the request. This address could be virtual or 75 * physical, depending on the system configuration. */ 76 Addr addr; 77 78 /** The size of the request or transfer. */ 79 int size; 80 81 /** Device address (e.g., bus ID) of the source of the 82 * transaction. The source is not responsible for setting this 83 * field; it is set implicitly by the interconnect when the 84 * packet * is first sent. */ 85 short src; 86 87 /** Device address (e.g., bus ID) of the destination of the 88 * transaction. The special value Broadcast indicates that the 89 * packet should be routed based on its address. This field is 90 * initialized in the constructor and is thus always valid 91 * (unlike * addr, size, and src). */ 92 short dest; 93 94 /** Is the 'addr' field valid? */ 95 bool addrValid; 96 /** Is the 'size' field valid? */ 97 bool sizeValid; 98 /** Is the 'src' field valid? */ 99 bool srcValid; 100 101 public: 102 103 /** The special destination address indicating that the packet 104 * should be routed based on its address. */ 105 static const short Broadcast = -1; 106 107 /** A pointer to the original request. */ 108 RequestPtr req; 109 110 /** A virtual base opaque structure used to hold coherence-related 111 * state. A specific subclass would be derived from this to 112 * carry state specific to a particular coherence protocol. */ 113 class CoherenceState { 114 public: 115 virtual ~CoherenceState() {} 116 }; 117 118 /** This packet's coherence state. Caches should use 119 * dynamic_cast<> to cast to the state appropriate for the 120 * system's coherence protocol. */ 121 CoherenceState *coherence; 122 123 /** A virtual base opaque structure used to hold state associated 124 * with the packet but specific to the sending device (e.g., an 125 * MSHR). A pointer to this state is returned in the packet's 126 * response so that the sender can quickly look up the state 127 * needed to process it. A specific subclass would be derived 128 * from this to carry state specific to a particular sending 129 * device. */ 130 class SenderState { 131 public: 132 virtual ~SenderState() {} 133 }; 134 135 /** This packet's sender state. Devices should use dynamic_cast<> 136 * to cast to the state appropriate to the sender. */ 137 SenderState *senderState; 138 139 private: 140 /** List of command attributes. */ 141 enum CommandAttribute 142 { 143 IsRead = 1 << 0, 144 IsWrite = 1 << 1, 145 IsPrefetch = 1 << 2, 146 IsInvalidate = 1 << 3, 147 IsRequest = 1 << 4, 148 IsResponse = 1 << 5, 149 NeedsResponse = 1 << 6, 150 }; 151 152 public: 153 /** List of all commands associated with a packet. */ 154 enum Command 155 { 156 ReadReq = IsRead | IsRequest | NeedsResponse, 157 WriteReq = IsWrite | IsRequest | NeedsResponse, 158 WriteReqNoAck = IsWrite | IsRequest, 159 ReadResp = IsRead | IsResponse, 160 WriteResp = IsWrite | IsResponse 161 }; 162 163 /** Return the string name of the cmd field (for debugging and 164 * tracing). */ 165 const std::string &cmdString() const; 166 167 /** The command field of the packet. */ 168 Command cmd; 169 170 bool isRead() { return (cmd & IsRead) != 0; } 171 bool isRequest() { return (cmd & IsRequest) != 0; } 172 bool isResponse() { return (cmd & IsResponse) != 0; } 173 bool needsResponse() { return (cmd & NeedsResponse) != 0; } 174 175 /** Possible results of a packet's request. */ 176 enum Result 177 { 178 Success, 179 BadAddress, 180 Unknown 181 }; 182 183 /** The result of this packet's request. */ 184 Result result; 185 186 /** Accessor function that returns the source index of the packet. */ 187 short getSrc() const { assert(srcValid); return src; } 188 void setSrc(short _src) { src = _src; srcValid = true; } 189 190 /** Accessor function that returns the destination index of 191 the packet. */ 192 short getDest() const { return dest; } 193 void setDest(short _dest) { dest = _dest; } 194 195 Addr getAddr() const { assert(addrValid); return addr; } 196 void setAddr(Addr _addr) { addr = _addr; addrValid = true; } 197 198 int getSize() const { assert(sizeValid); return size; } 199 void setSize(int _size) { size = _size; sizeValid = true; } 200 201 /** Constructor. Note that a Request object must be constructed 202 * first, but the Requests's physical address and size fields 203 * need not be valid. The command and destination addresses 204 * must be supplied. */ 205 Packet(Request *_req, Command _cmd, short _dest) 206 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 207 addr(_req->paddr), size(_req->size), dest(_dest), 208 addrValid(_req->validPaddr), sizeValid(_req->validSize), 209 srcValid(false), 210 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 211 result(Unknown) 212 { 213 } 214 215 /** Destructor. */ 216 ~Packet() 217 { deleteData(); } 218 219 /** Reinitialize packet address and size from the associated 220 * Request object, and reset other fields that may have been 221 * modified by a previous transaction. Typically called when a 222 * statically allocated Request/Packet pair is reused for 223 * multiple transactions. */ 224 void reinitFromRequest() { 225 assert(req->validPaddr); 226 setAddr(req->paddr); 227 assert(req->validSize); 228 setSize(req->size); 229 result = Unknown; 230 if (dynamicData) { 231 deleteData(); 232 dynamicData = false; 233 arrayData = false; 234 } 235 } 236 237 /** Take a request packet and modify it in place to be suitable 238 * for returning as a response to that request. Used for timing 239 * accesses only. For atomic and functional accesses, the 240 * request packet is always implicitly passed back *without* 241 * modifying the command or destination fields, so this function 242 * should not be called. */ 243 void makeTimingResponse() { 244 assert(needsResponse()); 245 int icmd = (int)cmd; 246 icmd &= ~(IsRequest | NeedsResponse); 247 icmd |= IsResponse; 248 cmd = (Command)icmd; 249 dest = src; 250 srcValid = false; 251 } 252 253 /** Set the data pointer to the following value that should not be freed. */ 254 template <typename T> 255 void dataStatic(T *p); 256 257 /** Set the data pointer to a value that should have delete [] called on it. 258 */ 259 template <typename T> 260 void dataDynamicArray(T *p); 261 262 /** set the data pointer to a value that should have delete called on it. */ 263 template <typename T> 264 void dataDynamic(T *p); 265 266 /** return the value of what is pointed to in the packet. */ 267 template <typename T> 268 T get(); 269 270 /** get a pointer to the data ptr. */ 271 template <typename T> 272 T* getPtr(); 273 274 /** set the value in the data pointer to v. */ 275 template <typename T> 276 void set(T v); 277 278 /** delete the data pointed to in the data pointer. Ok to call to matter how 279 * data was allocted. */ 280 void deleteData(); 281 282 /** If there isn't data in the packet, allocate some. */ 283 void allocate(); 284 285 /** Do the packet modify the same addresses. */ 286 bool intersect(Packet *p); 287}; 288 289bool fixPacket(Packet *func, Packet *timing); 290#endif //__MEM_PACKET_HH 291