xbar.cc revision 9278
1/* 2 * Copyright (c) 2011-2012 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2006 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Ali Saidi 41 * Andreas Hansson 42 * William Wang 43 */ 44 45/** 46 * @file 47 * Definition of a bus object. 48 */ 49 50#include "base/misc.hh" 51#include "base/trace.hh" 52#include "debug/Bus.hh" 53#include "debug/BusAddrRanges.hh" 54#include "debug/Drain.hh" 55#include "mem/bus.hh" 56 57BaseBus::BaseBus(const BaseBusParams *p) 58 : MemObject(p), 59 headerCycles(p->header_cycles), width(p->width), 60 defaultPortID(InvalidPortID), 61 useDefaultRange(p->use_default_range), 62 blockSize(p->block_size) 63{} 64 65BaseBus::~BaseBus() 66{ 67 for (MasterPortIter m = masterPorts.begin(); m != masterPorts.end(); 68 ++m) { 69 delete *m; 70 } 71 72 for (SlavePortIter s = slavePorts.begin(); s != slavePorts.end(); 73 ++s) { 74 delete *s; 75 } 76} 77 78void 79BaseBus::init() 80{ 81 // determine the maximum peer block size, look at both the 82 // connected master and slave modules 83 uint32_t peer_block_size = 0; 84 85 for (MasterPortConstIter m = masterPorts.begin(); m != masterPorts.end(); 86 ++m) { 87 peer_block_size = std::max((*m)->peerBlockSize(), peer_block_size); 88 } 89 90 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 91 ++s) { 92 peer_block_size = std::max((*s)->peerBlockSize(), peer_block_size); 93 } 94 95 // if the peers do not have a block size, use the default value 96 // set through the bus parameters 97 if (peer_block_size != 0) 98 blockSize = peer_block_size; 99 100 // check if the block size is a value known to work 101 if (blockSize != 16 || blockSize != 32 || blockSize != 64 || 102 blockSize != 128) 103 warn_once("Block size is neither 16, 32, 64 or 128 bytes.\n"); 104} 105 106MasterPort & 107BaseBus::getMasterPort(const std::string &if_name, int idx) 108{ 109 if (if_name == "master" && idx < masterPorts.size()) { 110 // the master port index translates directly to the vector position 111 return *masterPorts[idx]; 112 } else if (if_name == "default") { 113 return *masterPorts[defaultPortID]; 114 } else { 115 return MemObject::getMasterPort(if_name, idx); 116 } 117} 118 119SlavePort & 120BaseBus::getSlavePort(const std::string &if_name, int idx) 121{ 122 if (if_name == "slave" && idx < slavePorts.size()) { 123 // the slave port index translates directly to the vector position 124 return *slavePorts[idx]; 125 } else { 126 return MemObject::getSlavePort(if_name, idx); 127 } 128} 129 130Tick 131BaseBus::calcPacketTiming(PacketPtr pkt) 132{ 133 // determine the current time rounded to the closest following 134 // clock edge 135 Tick now = nextCycle(); 136 137 Tick headerTime = now + headerCycles * clock; 138 139 // The packet will be sent. Figure out how long it occupies the bus, and 140 // how much of that time is for the first "word", aka bus width. 141 int numCycles = 0; 142 if (pkt->hasData()) { 143 // If a packet has data, it needs ceil(size/width) cycles to send it 144 int dataSize = pkt->getSize(); 145 numCycles += dataSize/width; 146 if (dataSize % width) 147 numCycles++; 148 } 149 150 // The first word will be delivered after the current tick, the delivery 151 // of the address if any, and one bus cycle to deliver the data 152 pkt->firstWordTime = headerTime + clock; 153 154 pkt->finishTime = headerTime + numCycles * clock; 155 156 return headerTime; 157} 158 159template <typename PortClass> 160BaseBus::Layer<PortClass>::Layer(BaseBus& _bus, const std::string& _name, 161 Tick _clock) : 162 bus(_bus), _name(_name), state(IDLE), clock(_clock), drainEvent(NULL), 163 releaseEvent(this) 164{ 165} 166 167template <typename PortClass> 168void BaseBus::Layer<PortClass>::occupyLayer(Tick until) 169{ 170 // ensure the state is busy or in retry and never idle at this 171 // point, as the bus should transition from idle as soon as it has 172 // decided to forward the packet to prevent any follow-on calls to 173 // sendTiming seeing an unoccupied bus 174 assert(state != IDLE); 175 176 // note that we do not change the bus state here, if we are going 177 // from idle to busy it is handled by tryTiming, and if we 178 // are in retry we should remain in retry such that 179 // succeededTiming still sees the accurate state 180 181 // until should never be 0 as express snoops never occupy the bus 182 assert(until != 0); 183 bus.schedule(releaseEvent, until); 184 185 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 186 curTick(), until); 187} 188 189template <typename PortClass> 190bool 191BaseBus::Layer<PortClass>::tryTiming(PortClass* port) 192{ 193 // first we see if the bus is busy, next we check if we are in a 194 // retry with a port other than the current one 195 if (state == BUSY || (state == RETRY && port != retryList.front())) { 196 // put the port at the end of the retry list 197 retryList.push_back(port); 198 return false; 199 } 200 201 // update the state which is shared for request, response and 202 // snoop responses, if we were idle we are now busy, if we are in 203 // a retry, then do not change 204 if (state == IDLE) 205 state = BUSY; 206 207 return true; 208} 209 210template <typename PortClass> 211void 212BaseBus::Layer<PortClass>::succeededTiming(Tick busy_time) 213{ 214 // if a retrying port succeeded, also take it off the retry list 215 if (state == RETRY) { 216 DPRINTF(BaseBus, "Remove retry from list %s\n", 217 retryList.front()->name()); 218 retryList.pop_front(); 219 state = BUSY; 220 } 221 222 // we should either have gone from idle to busy in the 223 // tryTiming test, or just gone from a retry to busy 224 assert(state == BUSY); 225 226 // occupy the bus accordingly 227 occupyLayer(busy_time); 228} 229 230template <typename PortClass> 231void 232BaseBus::Layer<PortClass>::failedTiming(PortClass* port, Tick busy_time) 233{ 234 // if we are not in a retry, i.e. busy (but never idle), or we are 235 // in a retry but not for the current port, then add the port at 236 // the end of the retry list 237 if (state != RETRY || port != retryList.front()) { 238 retryList.push_back(port); 239 } 240 241 // even if we retried the current one and did not succeed, 242 // we are no longer retrying but instead busy 243 state = BUSY; 244 245 // occupy the bus accordingly 246 occupyLayer(busy_time); 247} 248 249template <typename PortClass> 250void 251BaseBus::Layer<PortClass>::releaseLayer() 252{ 253 // releasing the bus means we should now be idle 254 assert(state == BUSY); 255 assert(!releaseEvent.scheduled()); 256 257 // update the state 258 state = IDLE; 259 260 // bus is now idle, so if someone is waiting we can retry 261 if (!retryList.empty()) { 262 // note that we block (return false on recvTiming) both 263 // because the bus is busy and because the destination is 264 // busy, and in the latter case the bus may be released before 265 // we see a retry from the destination 266 retryWaiting(); 267 } else if (drainEvent) { 268 DPRINTF(Drain, "Bus done draining, processing drain event\n"); 269 //If we weren't able to drain before, do it now. 270 drainEvent->process(); 271 // Clear the drain event once we're done with it. 272 drainEvent = NULL; 273 } 274} 275 276template <typename PortClass> 277void 278BaseBus::Layer<PortClass>::retryWaiting() 279{ 280 // this should never be called with an empty retry list 281 assert(!retryList.empty()); 282 283 // we always go to retrying from idle 284 assert(state == IDLE); 285 286 // update the state which is shared for request, response and 287 // snoop responses 288 state = RETRY; 289 290 // note that we might have blocked on the receiving port being 291 // busy (rather than the bus itself) and now call retry before the 292 // destination called retry on the bus 293 retryList.front()->sendRetry(); 294 295 // If the bus is still in the retry state, sendTiming wasn't 296 // called in zero time (e.g. the cache does this) 297 if (state == RETRY) { 298 retryList.pop_front(); 299 300 //Burn a cycle for the missed grant. 301 302 // update the state which is shared for request, response and 303 // snoop responses 304 state = BUSY; 305 306 // determine the current time rounded to the closest following 307 // clock edge 308 Tick now = bus.nextCycle(); 309 310 occupyLayer(now + clock); 311 } 312} 313 314template <typename PortClass> 315void 316BaseBus::Layer<PortClass>::recvRetry() 317{ 318 // we got a retry from a peer that we tried to send something to 319 // and failed, but we sent it on the account of someone else, and 320 // that source port should be on our retry list, however if the 321 // bus layer is released before this happens and the retry (from 322 // the bus point of view) is successful then this no longer holds 323 // and we could in fact have an empty retry list 324 if (retryList.empty()) 325 return; 326 327 // if the bus layer is idle 328 if (state == IDLE) { 329 // note that we do not care who told us to retry at the moment, we 330 // merely let the first one on the retry list go 331 retryWaiting(); 332 } 333} 334 335PortID 336BaseBus::findPort(Addr addr) 337{ 338 /* An interval tree would be a better way to do this. --ali. */ 339 PortID dest_id = checkPortCache(addr); 340 if (dest_id != InvalidPortID) 341 return dest_id; 342 343 // Check normal port ranges 344 PortMapConstIter i = portMap.find(RangeSize(addr,1)); 345 if (i != portMap.end()) { 346 dest_id = i->second; 347 updatePortCache(dest_id, i->first.start, i->first.end); 348 return dest_id; 349 } 350 351 // Check if this matches the default range 352 if (useDefaultRange) { 353 AddrRangeConstIter a_end = defaultRange.end(); 354 for (AddrRangeConstIter i = defaultRange.begin(); i != a_end; i++) { 355 if (*i == addr) { 356 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 357 addr); 358 return defaultPortID; 359 } 360 } 361 } else if (defaultPortID != InvalidPortID) { 362 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 363 "will use default port\n", addr); 364 return defaultPortID; 365 } 366 367 // we should use the range for the default port and it did not 368 // match, or the default port is not set 369 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 370 name()); 371} 372 373/** Function called by the port when the bus is receiving a range change.*/ 374void 375BaseBus::recvRangeChange(PortID master_port_id) 376{ 377 AddrRangeIter iter; 378 379 if (inRecvRangeChange.count(master_port_id)) 380 return; 381 inRecvRangeChange.insert(master_port_id); 382 383 DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", 384 master_port_id); 385 386 clearPortCache(); 387 if (master_port_id == defaultPortID) { 388 defaultRange.clear(); 389 // Only try to update these ranges if the user set a default responder. 390 if (useDefaultRange) { 391 // get the address ranges of the connected slave port 392 AddrRangeList ranges = 393 masterPorts[master_port_id]->getAddrRanges(); 394 for(iter = ranges.begin(); iter != ranges.end(); iter++) { 395 defaultRange.push_back(*iter); 396 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n", 397 iter->start, iter->end); 398 } 399 } 400 } else { 401 402 assert(master_port_id < masterPorts.size() && master_port_id >= 0); 403 MasterPort *port = masterPorts[master_port_id]; 404 405 // Clean out any previously existent ids 406 for (PortMapIter portIter = portMap.begin(); 407 portIter != portMap.end(); ) { 408 if (portIter->second == master_port_id) 409 portMap.erase(portIter++); 410 else 411 portIter++; 412 } 413 414 // get the address ranges of the connected slave port 415 AddrRangeList ranges = port->getAddrRanges(); 416 417 for (iter = ranges.begin(); iter != ranges.end(); iter++) { 418 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n", 419 iter->start, iter->end, master_port_id); 420 if (portMap.insert(*iter, master_port_id) == portMap.end()) { 421 PortID conflict_id = portMap.find(*iter)->second; 422 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 423 name(), 424 masterPorts[master_port_id]->getSlavePort().name(), 425 masterPorts[conflict_id]->getSlavePort().name()); 426 } 427 } 428 } 429 DPRINTF(BusAddrRanges, "port list has %d entries\n", portMap.size()); 430 431 // tell all our neighbouring master ports that our address range 432 // has changed 433 for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end(); 434 ++p) 435 (*p)->sendRangeChange(); 436 437 inRecvRangeChange.erase(master_port_id); 438} 439 440AddrRangeList 441BaseBus::getAddrRanges() const 442{ 443 AddrRangeList ranges; 444 445 DPRINTF(BusAddrRanges, "received address range request, returning:\n"); 446 447 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 448 dflt_iter != defaultRange.end(); dflt_iter++) { 449 ranges.push_back(*dflt_iter); 450 DPRINTF(BusAddrRanges, " -- Dflt: %#llx : %#llx\n",dflt_iter->start, 451 dflt_iter->end); 452 } 453 for (PortMapConstIter portIter = portMap.begin(); 454 portIter != portMap.end(); portIter++) { 455 bool subset = false; 456 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 457 dflt_iter != defaultRange.end(); dflt_iter++) { 458 if ((portIter->first.start < dflt_iter->start && 459 portIter->first.end >= dflt_iter->start) || 460 (portIter->first.start < dflt_iter->end && 461 portIter->first.end >= dflt_iter->end)) 462 fatal("Devices can not set ranges that itersect the default set\ 463 but are not a subset of the default set.\n"); 464 if (portIter->first.start >= dflt_iter->start && 465 portIter->first.end <= dflt_iter->end) { 466 subset = true; 467 DPRINTF(BusAddrRanges, " -- %#llx : %#llx is a SUBSET\n", 468 portIter->first.start, portIter->first.end); 469 } 470 } 471 if (!subset) { 472 ranges.push_back(portIter->first); 473 DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n", 474 portIter->first.start, portIter->first.end); 475 } 476 } 477 478 return ranges; 479} 480 481unsigned 482BaseBus::deviceBlockSize() const 483{ 484 return blockSize; 485} 486 487template <typename PortClass> 488unsigned int 489BaseBus::Layer<PortClass>::drain(Event * de) 490{ 491 //We should check that we're not "doing" anything, and that noone is 492 //waiting. We might be idle but have someone waiting if the device we 493 //contacted for a retry didn't actually retry. 494 if (!retryList.empty() || state != IDLE) { 495 DPRINTF(Drain, "Bus not drained\n"); 496 drainEvent = de; 497 return 1; 498 } 499 return 0; 500} 501 502/** 503 * Bus layer template instantiations. Could be removed with _impl.hh 504 * file, but since there are only two given options (MasterPort and 505 * SlavePort) it seems a bit excessive at this point. 506 */ 507template class BaseBus::Layer<SlavePort>; 508template class BaseBus::Layer<MasterPort>; 509