packet.hh revision 2811
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 * Authors: Ron Dreslinski 29 * Steve Reinhardt 30 * Ali Saidi 31 */ 32 33/** 34 * @file 35 * Declaration of the Packet class. 36 */ 37 38#ifndef __MEM_PACKET_HH__ 39#define __MEM_PACKET_HH__ 40 41#include "mem/request.hh" 42#include "arch/isa_traits.hh" 43#include "sim/root.hh" 44 45struct Packet; 46typedef Packet* PacketPtr; 47typedef uint8_t* PacketDataPtr; 48 49//For statistics we need max number of commands, hard code it at 50//20 for now. @todo fix later 51#define NUM_MEM_CMDS 1 << 9 52 53/** 54 * A Packet is used to encapsulate a transfer between two objects in 55 * the memory system (e.g., the L1 and L2 cache). (In contrast, a 56 * single Request travels all the way from the requester to the 57 * ultimate destination and back, possibly being conveyed by several 58 * different Packets along the way.) 59 */ 60class Packet 61{ 62 private: 63 /** A pointer to the data being transfered. It can be differnt 64 * sizes at each level of the heirarchy so it belongs in the 65 * packet, not request. This may or may not be populated when a 66 * responder recieves the packet. If not populated it memory 67 * should be allocated. 68 */ 69 PacketDataPtr data; 70 71 /** Is the data pointer set to a value that shouldn't be freed 72 * when the packet is destroyed? */ 73 bool staticData; 74 /** The data pointer points to a value that should be freed when 75 * the packet is destroyed. */ 76 bool dynamicData; 77 /** the data pointer points to an array (thus delete [] ) needs to 78 * be called on it rather than simply delete.*/ 79 bool arrayData; 80 81 82 /** The address of the request. This address could be virtual or 83 * physical, depending on the system configuration. */ 84 Addr addr; 85 86 /** The size of the request or transfer. */ 87 int size; 88 89 /** Device address (e.g., bus ID) of the source of the 90 * transaction. The source is not responsible for setting this 91 * field; it is set implicitly by the interconnect when the 92 * packet * is first sent. */ 93 short src; 94 95 /** Device address (e.g., bus ID) of the destination of the 96 * transaction. The special value Broadcast indicates that the 97 * packet should be routed based on its address. This field is 98 * initialized in the constructor and is thus always valid 99 * (unlike * addr, size, and src). */ 100 short dest; 101 102 /** Are the 'addr' and 'size' fields valid? */ 103 bool addrSizeValid; 104 /** Is the 'src' field valid? */ 105 bool srcValid; 106 107 public: 108 109 /** Used to calculate latencies for each packet.*/ 110 Tick time; 111 112 /** The special destination address indicating that the packet 113 * should be routed based on its address. */ 114 static const short Broadcast = -1; 115 116 /** A pointer to the original request. */ 117 RequestPtr req; 118 119 /** A virtual base opaque structure used to hold coherence-related 120 * state. A specific subclass would be derived from this to 121 * carry state specific to a particular coherence protocol. */ 122 class CoherenceState { 123 public: 124 virtual ~CoherenceState() {} 125 }; 126 127 /** This packet's coherence state. Caches should use 128 * dynamic_cast<> to cast to the state appropriate for the 129 * system's coherence protocol. */ 130 CoherenceState *coherence; 131 132 /** A virtual base opaque structure used to hold state associated 133 * with the packet but specific to the sending device (e.g., an 134 * MSHR). A pointer to this state is returned in the packet's 135 * response so that the sender can quickly look up the state 136 * needed to process it. A specific subclass would be derived 137 * from this to carry state specific to a particular sending 138 * device. */ 139 class SenderState { 140 public: 141 virtual ~SenderState() {} 142 }; 143 144 /** This packet's sender state. Devices should use dynamic_cast<> 145 * to cast to the state appropriate to the sender. */ 146 SenderState *senderState; 147 148 private: 149 /** List of command attributes. */ 150 enum CommandAttribute 151 { 152 IsRead = 1 << 0, 153 IsWrite = 1 << 1, 154 IsPrefetch = 1 << 2, 155 IsInvalidate = 1 << 3, 156 IsRequest = 1 << 4, 157 IsResponse = 1 << 5, 158 NeedsResponse = 1 << 6, 159 IsSWPrefetch = 1 << 7, 160 IsHWPrefetch = 1 << 8 161 }; 162 163 public: 164 /** List of all commands associated with a packet. */ 165 enum Command 166 { 167 ReadReq = IsRead | IsRequest | NeedsResponse, 168 WriteReq = IsWrite | IsRequest | NeedsResponse, 169 WriteReqNoAck = IsWrite | IsRequest, 170 ReadResp = IsRead | IsResponse, 171 WriteResp = IsWrite | IsResponse, 172 Writeback = IsWrite | IsRequest, 173 SoftPFReq = IsRead | IsRequest | IsSWPrefetch | NeedsResponse, 174 HardPFReq = IsRead | IsRequest | IsHWPrefetch | NeedsResponse, 175 SoftPFResp = IsRead | IsRequest | IsSWPrefetch | IsResponse, 176 HardPFResp = IsRead | IsRequest | IsHWPrefetch | IsResponse 177 }; 178 179 /** Return the string name of the cmd field (for debugging and 180 * tracing). */ 181 const std::string &cmdString() const; 182 183 /** Reutrn the string to a cmd given by idx. */ 184 const std::string &cmdIdxToString(Command idx); 185 186 /** Return the index of this command. */ 187 inline int cmdToIndex() const { return (int) cmd; } 188 189 /** The command field of the packet. */ 190 Command cmd; 191 192 bool isRead() { return (cmd & IsRead) != 0; } 193 bool isRequest() { return (cmd & IsRequest) != 0; } 194 bool isResponse() { return (cmd & IsResponse) != 0; } 195 bool needsResponse() { return (cmd & NeedsResponse) != 0; } 196 197 /** Possible results of a packet's request. */ 198 enum Result 199 { 200 Success, 201 BadAddress, 202 Nacked, 203 Unknown 204 }; 205 206 /** The result of this packet's request. */ 207 Result result; 208 209 /** Accessor function that returns the source index of the packet. */ 210 short getSrc() const { assert(srcValid); return src; } 211 void setSrc(short _src) { src = _src; srcValid = true; } 212 213 /** Accessor function that returns the destination index of 214 the packet. */ 215 short getDest() const { return dest; } 216 void setDest(short _dest) { dest = _dest; } 217 218 Addr getAddr() const { assert(addrSizeValid); return addr; } 219 int getSize() const { assert(addrSizeValid); return size; } 220 221 /** Constructor. Note that a Request object must be constructed 222 * first, but the Requests's physical address and size fields 223 * need not be valid. The command and destination addresses 224 * must be supplied. */ 225 Packet(Request *_req, Command _cmd, short _dest) 226 : data(NULL), staticData(false), dynamicData(false), arrayData(false), 227 addr(_req->paddr), size(_req->size), dest(_dest), 228 addrSizeValid(_req->validPaddr), 229 srcValid(false), 230 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd), 231 result(Unknown) 232 { 233 } 234 235 /** Destructor. */ 236 ~Packet() 237 { deleteData(); } 238 239 /** Reinitialize packet address and size from the associated 240 * Request object, and reset other fields that may have been 241 * modified by a previous transaction. Typically called when a 242 * statically allocated Request/Packet pair is reused for 243 * multiple transactions. */ 244 void reinitFromRequest() { 245 assert(req->validPaddr); 246 addr = req->paddr; 247 size = req->size; 248 addrSizeValid = true; 249 result = Unknown; 250 if (dynamicData) { 251 deleteData(); 252 dynamicData = false; 253 arrayData = false; 254 } 255 } 256 257 /** Take a request packet and modify it in place to be suitable 258 * for returning as a response to that request. Used for timing 259 * accesses only. For atomic and functional accesses, the 260 * request packet is always implicitly passed back *without* 261 * modifying the command or destination fields, so this function 262 * should not be called. */ 263 void makeTimingResponse() { 264 assert(needsResponse()); 265 int icmd = (int)cmd; 266 icmd &= ~(IsRequest | NeedsResponse); 267 icmd |= IsResponse; 268 cmd = (Command)icmd; 269 dest = src; 270 srcValid = false; 271 } 272 273 /** Take a request packet that has been returned as NACKED and modify it so 274 * that it can be sent out again. Only packets that need a response can be 275 * NACKED, so verify that that is true. */ 276 void reinitNacked() { 277 assert(needsResponse() && result == Nacked); 278 dest = Broadcast; 279 result = Unknown; 280 } 281 282 283 /** Set the data pointer to the following value that should not be freed. */ 284 template <typename T> 285 void dataStatic(T *p); 286 287 /** Set the data pointer to a value that should have delete [] called on it. 288 */ 289 template <typename T> 290 void dataDynamicArray(T *p); 291 292 /** set the data pointer to a value that should have delete called on it. */ 293 template <typename T> 294 void dataDynamic(T *p); 295 296 /** return the value of what is pointed to in the packet. */ 297 template <typename T> 298 T get(); 299 300 /** get a pointer to the data ptr. */ 301 template <typename T> 302 T* getPtr(); 303 304 /** set the value in the data pointer to v. */ 305 template <typename T> 306 void set(T v); 307 308 /** delete the data pointed to in the data pointer. Ok to call to matter how 309 * data was allocted. */ 310 void deleteData(); 311 312 /** If there isn't data in the packet, allocate some. */ 313 void allocate(); 314 315 /** Do the packet modify the same addresses. */ 316 bool intersect(Packet *p); 317}; 318 319bool fixPacket(Packet *func, Packet *timing); 320#endif //__MEM_PACKET_HH 321