bridge.hh revision 8975
14776Sgblack@eecs.umich.edu/* 24776Sgblack@eecs.umich.edu * Copyright (c) 2011-2012 ARM Limited 34776Sgblack@eecs.umich.edu * All rights reserved 44776Sgblack@eecs.umich.edu * 54776Sgblack@eecs.umich.edu * The license below extends only to copyright in the software and shall 64776Sgblack@eecs.umich.edu * not be construed as granting a license to any other intellectual 74776Sgblack@eecs.umich.edu * property including but not limited to intellectual property relating 84776Sgblack@eecs.umich.edu * to a hardware implementation of the functionality of the software 94776Sgblack@eecs.umich.edu * licensed hereunder. You may use the software subject to the license 104776Sgblack@eecs.umich.edu * terms below provided that you ensure that this notice is replicated 114776Sgblack@eecs.umich.edu * unmodified and in its entirety in all distributions of the software, 124776Sgblack@eecs.umich.edu * modified or unmodified, in source code or in binary form. 134776Sgblack@eecs.umich.edu * 144776Sgblack@eecs.umich.edu * Copyright (c) 2006 The Regents of The University of Michigan 154776Sgblack@eecs.umich.edu * All rights reserved. 164776Sgblack@eecs.umich.edu * 174776Sgblack@eecs.umich.edu * Redistribution and use in source and binary forms, with or without 184776Sgblack@eecs.umich.edu * modification, are permitted provided that the following conditions are 194776Sgblack@eecs.umich.edu * met: redistributions of source code must retain the above copyright 204776Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer; 214776Sgblack@eecs.umich.edu * redistributions in binary form must reproduce the above copyright 224776Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer in the 234776Sgblack@eecs.umich.edu * documentation and/or other materials provided with the distribution; 244776Sgblack@eecs.umich.edu * neither the name of the copyright holders nor the names of its 254776Sgblack@eecs.umich.edu * contributors may be used to endorse or promote products derived from 264776Sgblack@eecs.umich.edu * this software without specific prior written permission. 274776Sgblack@eecs.umich.edu * 284776Sgblack@eecs.umich.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 294776Sgblack@eecs.umich.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 304776Sgblack@eecs.umich.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 314776Sgblack@eecs.umich.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 324776Sgblack@eecs.umich.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 334776Sgblack@eecs.umich.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 344776Sgblack@eecs.umich.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 354832Snate@binkert.org * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 364776Sgblack@eecs.umich.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 374776Sgblack@eecs.umich.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 384776Sgblack@eecs.umich.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 394776Sgblack@eecs.umich.edu * 404776Sgblack@eecs.umich.edu * Authors: Ali Saidi 414776Sgblack@eecs.umich.edu * Steve Reinhardt 424776Sgblack@eecs.umich.edu * Andreas Hansson 434776Sgblack@eecs.umich.edu */ 444776Sgblack@eecs.umich.edu 454776Sgblack@eecs.umich.edu/** 464776Sgblack@eecs.umich.edu * @file 474776Sgblack@eecs.umich.edu * Declaration of a memory-mapped bus bridge that connects a master 484776Sgblack@eecs.umich.edu * and a slave through a request and response queue. 494776Sgblack@eecs.umich.edu */ 504776Sgblack@eecs.umich.edu 514776Sgblack@eecs.umich.edu#ifndef __MEM_BRIDGE_HH__ 524776Sgblack@eecs.umich.edu#define __MEM_BRIDGE_HH__ 534776Sgblack@eecs.umich.edu 544776Sgblack@eecs.umich.edu#include <list> 554776Sgblack@eecs.umich.edu#include <queue> 564776Sgblack@eecs.umich.edu#include <string> 574776Sgblack@eecs.umich.edu 584776Sgblack@eecs.umich.edu#include "base/fast_alloc.hh" 594776Sgblack@eecs.umich.edu#include "base/types.hh" 604776Sgblack@eecs.umich.edu#include "mem/mem_object.hh" 614776Sgblack@eecs.umich.edu#include "mem/packet.hh" 624776Sgblack@eecs.umich.edu#include "mem/port.hh" 634776Sgblack@eecs.umich.edu#include "params/Bridge.hh" 644776Sgblack@eecs.umich.edu#include "sim/eventq.hh" 654776Sgblack@eecs.umich.edu 664776Sgblack@eecs.umich.edu/** 674776Sgblack@eecs.umich.edu * A bridge is used to interface two different busses (or in general a 684776Sgblack@eecs.umich.edu * memory-mapped master and slave), with buffering for requests and 694776Sgblack@eecs.umich.edu * responses. The bridge has a fixed delay for packets passing through 704776Sgblack@eecs.umich.edu * it and responds to a fixed set of address ranges. 714776Sgblack@eecs.umich.edu * 724776Sgblack@eecs.umich.edu * The bridge comprises a slave port and a master port, that buffer 734776Sgblack@eecs.umich.edu * outgoing responses and requests respectively. Buffer space is 744776Sgblack@eecs.umich.edu * reserved when a request arrives, also reserving response space 754776Sgblack@eecs.umich.edu * before forwarding the request. An incoming request is always 764776Sgblack@eecs.umich.edu * accepted (recvTiming returns true), but is potentially NACKed if 774776Sgblack@eecs.umich.edu * there is no request space or response space. 784776Sgblack@eecs.umich.edu */ 794776Sgblack@eecs.umich.educlass Bridge : public MemObject 804776Sgblack@eecs.umich.edu{ 814776Sgblack@eecs.umich.edu protected: 824776Sgblack@eecs.umich.edu 834776Sgblack@eecs.umich.edu /** 844776Sgblack@eecs.umich.edu * A packet buffer stores packets along with their sender state 854776Sgblack@eecs.umich.edu * and scheduled time for transmission. 864776Sgblack@eecs.umich.edu */ 874776Sgblack@eecs.umich.edu class PacketBuffer : public Packet::SenderState, public FastAlloc { 884776Sgblack@eecs.umich.edu 894776Sgblack@eecs.umich.edu public: 904776Sgblack@eecs.umich.edu Tick ready; 914776Sgblack@eecs.umich.edu PacketPtr pkt; 924776Sgblack@eecs.umich.edu bool nackedHere; 934776Sgblack@eecs.umich.edu Packet::SenderState *origSenderState; 944776Sgblack@eecs.umich.edu Packet::NodeID origSrc; 954776Sgblack@eecs.umich.edu bool expectResponse; 964776Sgblack@eecs.umich.edu 974776Sgblack@eecs.umich.edu PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false) 984776Sgblack@eecs.umich.edu : ready(t), pkt(_pkt), nackedHere(nack), 994776Sgblack@eecs.umich.edu origSenderState(_pkt->senderState), 1004776Sgblack@eecs.umich.edu origSrc(nack ? _pkt->getDest() : _pkt->getSrc() ), 1014776Sgblack@eecs.umich.edu expectResponse(_pkt->needsResponse() && !nack) 1024776Sgblack@eecs.umich.edu 1034776Sgblack@eecs.umich.edu { 1044776Sgblack@eecs.umich.edu if (!pkt->isResponse() && !nack) 1054776Sgblack@eecs.umich.edu pkt->senderState = this; 1064776Sgblack@eecs.umich.edu } 1074776Sgblack@eecs.umich.edu 1084776Sgblack@eecs.umich.edu void fixResponse(PacketPtr pkt) 1094776Sgblack@eecs.umich.edu { 1104776Sgblack@eecs.umich.edu assert(pkt->senderState == this); 1114776Sgblack@eecs.umich.edu pkt->setDest(origSrc); 1124776Sgblack@eecs.umich.edu pkt->senderState = origSenderState; 1134776Sgblack@eecs.umich.edu } 1144776Sgblack@eecs.umich.edu }; 1154776Sgblack@eecs.umich.edu 1164776Sgblack@eecs.umich.edu // Forward declaration to allow the slave port to have a pointer 1174776Sgblack@eecs.umich.edu class BridgeMasterPort; 1184776Sgblack@eecs.umich.edu 1194776Sgblack@eecs.umich.edu /** 1204776Sgblack@eecs.umich.edu * The port on the side that receives requests and sends 1214776Sgblack@eecs.umich.edu * responses. The slave port has a set of address ranges that it 1224776Sgblack@eecs.umich.edu * is responsible for. The slave port also has a buffer for the 1234776Sgblack@eecs.umich.edu * responses not yet sent. 1244776Sgblack@eecs.umich.edu */ 1254776Sgblack@eecs.umich.edu class BridgeSlavePort : public SlavePort 1264776Sgblack@eecs.umich.edu { 1274776Sgblack@eecs.umich.edu 1284776Sgblack@eecs.umich.edu private: 1294776Sgblack@eecs.umich.edu 1304776Sgblack@eecs.umich.edu /** A pointer to the bridge to which this port belongs. */ 1314776Sgblack@eecs.umich.edu Bridge *bridge; 1324776Sgblack@eecs.umich.edu 1334776Sgblack@eecs.umich.edu /** 1344776Sgblack@eecs.umich.edu * Master port on the other side of the bridge 1354776Sgblack@eecs.umich.edu * (connected to the other bus). 1364776Sgblack@eecs.umich.edu */ 1374776Sgblack@eecs.umich.edu BridgeMasterPort& masterPort; 1384776Sgblack@eecs.umich.edu 1394776Sgblack@eecs.umich.edu /** Minimum request delay though this bridge. */ 1404776Sgblack@eecs.umich.edu Tick delay; 1414776Sgblack@eecs.umich.edu 1424776Sgblack@eecs.umich.edu /** Min delay to respond with a nack. */ 1434776Sgblack@eecs.umich.edu Tick nackDelay; 1444776Sgblack@eecs.umich.edu 1454776Sgblack@eecs.umich.edu /** Address ranges to pass through the bridge */ 1464776Sgblack@eecs.umich.edu AddrRangeList ranges; 1474776Sgblack@eecs.umich.edu 148 /** 149 * Response packet queue. Response packets are held in this 150 * queue for a specified delay to model the processing delay 151 * of the bridge. 152 */ 153 std::list<PacketBuffer*> responseQueue; 154 155 /** Counter to track the outstanding responses. */ 156 unsigned int outstandingResponses; 157 158 /** If we're waiting for a retry to happen. */ 159 bool inRetry; 160 161 /** Max queue size for reserved responses. */ 162 unsigned int respQueueLimit; 163 164 /** 165 * Is this side blocked from accepting new response packets. 166 * 167 * @return true if the reserved space has reached the set limit 168 */ 169 bool respQueueFull(); 170 171 /** 172 * Turn the request packet into a NACK response and put it in 173 * the response queue and schedule its transmission. 174 * 175 * @param pkt the request packet to NACK 176 */ 177 void nackRequest(PacketPtr pkt); 178 179 /** 180 * Handle send event, scheduled when the packet at the head of 181 * the response queue is ready to transmit (for timing 182 * accesses only). 183 */ 184 void trySend(); 185 186 /** 187 * Private class for scheduling sending of responses from the 188 * response queue. 189 */ 190 class SendEvent : public Event 191 { 192 BridgeSlavePort& port; 193 194 public: 195 SendEvent(BridgeSlavePort& p) : port(p) {} 196 virtual void process() { port.trySend(); } 197 virtual const char *description() const { return "bridge send"; } 198 }; 199 200 /** Send event for the response queue. */ 201 SendEvent sendEvent; 202 203 public: 204 205 /** 206 * Constructor for the BridgeSlavePort. 207 * 208 * @param _name the port name including the owner 209 * @param _bridge the structural owner 210 * @param _masterPort the master port on the other side of the bridge 211 * @param _delay the delay from seeing a response to sending it 212 * @param _nack_delay the delay from a NACK to sending the response 213 * @param _resp_limit the size of the response queue 214 * @param _ranges a number of address ranges to forward 215 */ 216 BridgeSlavePort(const std::string &_name, Bridge *_bridge, 217 BridgeMasterPort& _masterPort, int _delay, 218 int _nack_delay, int _resp_limit, 219 std::vector<Range<Addr> > _ranges); 220 221 /** 222 * Queue a response packet to be sent out later and also schedule 223 * a send if necessary. 224 * 225 * @param pkt a response to send out after a delay 226 */ 227 void queueForSendTiming(PacketPtr pkt); 228 229 protected: 230 231 /** When receiving a timing request from the peer port, 232 pass it to the bridge. */ 233 virtual bool recvTimingReq(PacketPtr pkt); 234 235 /** When receiving a retry request from the peer port, 236 pass it to the bridge. */ 237 virtual void recvRetry(); 238 239 /** When receiving a Atomic requestfrom the peer port, 240 pass it to the bridge. */ 241 virtual Tick recvAtomic(PacketPtr pkt); 242 243 /** When receiving a Functional request from the peer port, 244 pass it to the bridge. */ 245 virtual void recvFunctional(PacketPtr pkt); 246 247 /** When receiving a address range request the peer port, 248 pass it to the bridge. */ 249 virtual AddrRangeList getAddrRanges(); 250 }; 251 252 253 /** 254 * Port on the side that forwards requests and receives 255 * responses. The master port has a buffer for the requests not 256 * yet sent. 257 */ 258 class BridgeMasterPort : public MasterPort 259 { 260 261 private: 262 263 /** A pointer to the bridge to which this port belongs. */ 264 Bridge* bridge; 265 266 /** 267 * Pointer to the slave port on the other side of the bridge 268 * (connected to the other bus). 269 */ 270 BridgeSlavePort& slavePort; 271 272 /** Minimum delay though this bridge. */ 273 Tick delay; 274 275 /** 276 * Request packet queue. Request packets are held in this 277 * queue for a specified delay to model the processing delay 278 * of the bridge. 279 */ 280 std::list<PacketBuffer*> requestQueue; 281 282 /** If we're waiting for a retry to happen. */ 283 bool inRetry; 284 285 /** Max queue size for request packets */ 286 unsigned int reqQueueLimit; 287 288 /** 289 * Handle send event, scheduled when the packet at the head of 290 * the outbound queue is ready to transmit (for timing 291 * accesses only). 292 */ 293 void trySend(); 294 295 /** 296 * Private class for scheduling sending of requests from the 297 * request queue. 298 */ 299 class SendEvent : public Event 300 { 301 BridgeMasterPort& port; 302 303 public: 304 SendEvent(BridgeMasterPort& p) : port(p) {} 305 virtual void process() { port.trySend(); } 306 virtual const char *description() const { return "bridge send"; } 307 }; 308 309 /** Send event for the request queue. */ 310 SendEvent sendEvent; 311 312 public: 313 314 /** 315 * Constructor for the BridgeMasterPort. 316 * 317 * @param _name the port name including the owner 318 * @param _bridge the structural owner 319 * @param _slavePort the slave port on the other side of the bridge 320 * @param _delay the delay from seeing a request to sending it 321 * @param _req_limit the size of the request queue 322 */ 323 BridgeMasterPort(const std::string &_name, Bridge *_bridge, 324 BridgeSlavePort& _slavePort, int _delay, 325 int _req_limit); 326 327 /** 328 * Is this side blocked from accepting new request packets. 329 * 330 * @return true if the occupied space has reached the set limit 331 */ 332 bool reqQueueFull(); 333 334 /** 335 * Queue a request packet to be sent out later and also schedule 336 * a send if necessary. 337 * 338 * @param pkt a request to send out after a delay 339 */ 340 void queueForSendTiming(PacketPtr pkt); 341 342 /** 343 * Check a functional request against the packets in our 344 * request queue. 345 * 346 * @param pkt packet to check against 347 * 348 * @return true if we find a match 349 */ 350 bool checkFunctional(PacketPtr pkt); 351 352 protected: 353 354 /** When receiving a timing request from the peer port, 355 pass it to the bridge. */ 356 virtual bool recvTimingResp(PacketPtr pkt); 357 358 /** When receiving a retry request from the peer port, 359 pass it to the bridge. */ 360 virtual void recvRetry(); 361 }; 362 363 /** Slave port of the bridge. */ 364 BridgeSlavePort slavePort; 365 366 /** Master port of the bridge. */ 367 BridgeMasterPort masterPort; 368 369 /** If this bridge should acknowledge writes. */ 370 bool ackWrites; 371 372 public: 373 typedef BridgeParams Params; 374 375 protected: 376 Params *_params; 377 378 public: 379 const Params *params() const { return _params; } 380 381 virtual MasterPort& getMasterPort(const std::string& if_name, 382 int idx = -1); 383 virtual SlavePort& getSlavePort(const std::string& if_name, int idx = -1); 384 385 virtual void init(); 386 387 Bridge(Params *p); 388}; 389 390#endif //__MEM_BUS_HH__ 391