xbar.cc revision 9405
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 gotAddrRanges(p->port_default_connection_count + 61 p->port_master_connection_count, false), 62 gotAllAddrRanges(false), defaultPortID(InvalidPortID), 63 useDefaultRange(p->use_default_range), 64 blockSize(p->block_size) 65{} 66 67BaseBus::~BaseBus() 68{ 69 for (MasterPortIter m = masterPorts.begin(); m != masterPorts.end(); 70 ++m) { 71 delete *m; 72 } 73 74 for (SlavePortIter s = slavePorts.begin(); s != slavePorts.end(); 75 ++s) { 76 delete *s; 77 } 78} 79 80void 81BaseBus::init() 82{ 83 // determine the maximum peer block size, look at both the 84 // connected master and slave modules 85 uint32_t peer_block_size = 0; 86 87 for (MasterPortConstIter m = masterPorts.begin(); m != masterPorts.end(); 88 ++m) { 89 peer_block_size = std::max((*m)->peerBlockSize(), peer_block_size); 90 } 91 92 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 93 ++s) { 94 peer_block_size = std::max((*s)->peerBlockSize(), peer_block_size); 95 } 96 97 // if the peers do not have a block size, use the default value 98 // set through the bus parameters 99 if (peer_block_size != 0) 100 blockSize = peer_block_size; 101 102 // check if the block size is a value known to work 103 if (!(blockSize == 16 || blockSize == 32 || blockSize == 64 || 104 blockSize == 128)) 105 warn_once("Block size is neither 16, 32, 64 or 128 bytes.\n"); 106} 107 108BaseMasterPort & 109BaseBus::getMasterPort(const std::string &if_name, PortID idx) 110{ 111 if (if_name == "master" && idx < masterPorts.size()) { 112 // the master port index translates directly to the vector position 113 return *masterPorts[idx]; 114 } else if (if_name == "default") { 115 return *masterPorts[defaultPortID]; 116 } else { 117 return MemObject::getMasterPort(if_name, idx); 118 } 119} 120 121BaseSlavePort & 122BaseBus::getSlavePort(const std::string &if_name, PortID idx) 123{ 124 if (if_name == "slave" && idx < slavePorts.size()) { 125 // the slave port index translates directly to the vector position 126 return *slavePorts[idx]; 127 } else { 128 return MemObject::getSlavePort(if_name, idx); 129 } 130} 131 132Tick 133BaseBus::calcPacketTiming(PacketPtr pkt) 134{ 135 // determine the current time rounded to the closest following 136 // clock edge 137 Tick now = nextCycle(); 138 139 Tick headerTime = now + headerCycles * clock; 140 141 // The packet will be sent. Figure out how long it occupies the bus, and 142 // how much of that time is for the first "word", aka bus width. 143 int numCycles = 0; 144 if (pkt->hasData()) { 145 // If a packet has data, it needs ceil(size/width) cycles to send it 146 int dataSize = pkt->getSize(); 147 numCycles += dataSize/width; 148 if (dataSize % width) 149 numCycles++; 150 } 151 152 // The first word will be delivered after the current tick, the delivery 153 // of the address if any, and one bus cycle to deliver the data 154 pkt->firstWordTime = headerTime + clock; 155 156 pkt->finishTime = headerTime + numCycles * clock; 157 158 return headerTime; 159} 160 161template <typename PortClass> 162BaseBus::Layer<PortClass>::Layer(BaseBus& _bus, const std::string& _name, 163 Tick _clock) : 164 Drainable(), 165 bus(_bus), _name(_name), state(IDLE), clock(_clock), drainManager(NULL), 166 releaseEvent(this) 167{ 168} 169 170template <typename PortClass> 171void BaseBus::Layer<PortClass>::occupyLayer(Tick until) 172{ 173 // ensure the state is busy or in retry and never idle at this 174 // point, as the bus should transition from idle as soon as it has 175 // decided to forward the packet to prevent any follow-on calls to 176 // sendTiming seeing an unoccupied bus 177 assert(state != IDLE); 178 179 // note that we do not change the bus state here, if we are going 180 // from idle to busy it is handled by tryTiming, and if we 181 // are in retry we should remain in retry such that 182 // succeededTiming still sees the accurate state 183 184 // until should never be 0 as express snoops never occupy the bus 185 assert(until != 0); 186 bus.schedule(releaseEvent, until); 187 188 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 189 curTick(), until); 190} 191 192template <typename PortClass> 193bool 194BaseBus::Layer<PortClass>::tryTiming(PortClass* port) 195{ 196 // first we see if the bus is busy, next we check if we are in a 197 // retry with a port other than the current one 198 if (state == BUSY || (state == RETRY && port != retryList.front())) { 199 // put the port at the end of the retry list 200 retryList.push_back(port); 201 return false; 202 } 203 204 // update the state which is shared for request, response and 205 // snoop responses, if we were idle we are now busy, if we are in 206 // a retry, then do not change 207 if (state == IDLE) 208 state = BUSY; 209 210 return true; 211} 212 213template <typename PortClass> 214void 215BaseBus::Layer<PortClass>::succeededTiming(Tick busy_time) 216{ 217 // if a retrying port succeeded, also take it off the retry list 218 if (state == RETRY) { 219 DPRINTF(BaseBus, "Remove retry from list %s\n", 220 retryList.front()->name()); 221 retryList.pop_front(); 222 state = BUSY; 223 } 224 225 // we should either have gone from idle to busy in the 226 // tryTiming test, or just gone from a retry to busy 227 assert(state == BUSY); 228 229 // occupy the bus accordingly 230 occupyLayer(busy_time); 231} 232 233template <typename PortClass> 234void 235BaseBus::Layer<PortClass>::failedTiming(PortClass* port, Tick busy_time) 236{ 237 // if we are not in a retry, i.e. busy (but never idle), or we are 238 // in a retry but not for the current port, then add the port at 239 // the end of the retry list 240 if (state != RETRY || port != retryList.front()) { 241 retryList.push_back(port); 242 } 243 244 // even if we retried the current one and did not succeed, 245 // we are no longer retrying but instead busy 246 state = BUSY; 247 248 // occupy the bus accordingly 249 occupyLayer(busy_time); 250} 251 252template <typename PortClass> 253void 254BaseBus::Layer<PortClass>::releaseLayer() 255{ 256 // releasing the bus means we should now be idle 257 assert(state == BUSY); 258 assert(!releaseEvent.scheduled()); 259 260 // update the state 261 state = IDLE; 262 263 // bus is now idle, so if someone is waiting we can retry 264 if (!retryList.empty()) { 265 // note that we block (return false on recvTiming) both 266 // because the bus is busy and because the destination is 267 // busy, and in the latter case the bus may be released before 268 // we see a retry from the destination 269 retryWaiting(); 270 } else if (drainManager) { 271 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 272 //If we weren't able to drain before, do it now. 273 drainManager->signalDrainDone(); 274 // Clear the drain event once we're done with it. 275 drainManager = NULL; 276 } 277} 278 279template <typename PortClass> 280void 281BaseBus::Layer<PortClass>::retryWaiting() 282{ 283 // this should never be called with an empty retry list 284 assert(!retryList.empty()); 285 286 // we always go to retrying from idle 287 assert(state == IDLE); 288 289 // update the state which is shared for request, response and 290 // snoop responses 291 state = RETRY; 292 293 // note that we might have blocked on the receiving port being 294 // busy (rather than the bus itself) and now call retry before the 295 // destination called retry on the bus 296 retryList.front()->sendRetry(); 297 298 // If the bus is still in the retry state, sendTiming wasn't 299 // called in zero time (e.g. the cache does this) 300 if (state == RETRY) { 301 retryList.pop_front(); 302 303 //Burn a cycle for the missed grant. 304 305 // update the state which is shared for request, response and 306 // snoop responses 307 state = BUSY; 308 309 // determine the current time rounded to the closest following 310 // clock edge 311 Tick now = bus.nextCycle(); 312 313 occupyLayer(now + clock); 314 } 315} 316 317template <typename PortClass> 318void 319BaseBus::Layer<PortClass>::recvRetry() 320{ 321 // we got a retry from a peer that we tried to send something to 322 // and failed, but we sent it on the account of someone else, and 323 // that source port should be on our retry list, however if the 324 // bus layer is released before this happens and the retry (from 325 // the bus point of view) is successful then this no longer holds 326 // and we could in fact have an empty retry list 327 if (retryList.empty()) 328 return; 329 330 // if the bus layer is idle 331 if (state == IDLE) { 332 // note that we do not care who told us to retry at the moment, we 333 // merely let the first one on the retry list go 334 retryWaiting(); 335 } 336} 337 338PortID 339BaseBus::findPort(Addr addr) 340{ 341 // we should never see any address lookups before we've got the 342 // ranges of all connected slave modules 343 assert(gotAllAddrRanges); 344 345 // Check the cache 346 PortID dest_id = checkPortCache(addr); 347 if (dest_id != InvalidPortID) 348 return dest_id; 349 350 // Check the address map interval tree 351 PortMapConstIter i = portMap.find(addr); 352 if (i != portMap.end()) { 353 dest_id = i->second; 354 updatePortCache(dest_id, i->first); 355 return dest_id; 356 } 357 358 // Check if this matches the default range 359 if (useDefaultRange) { 360 if (defaultRange.contains(addr)) { 361 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 362 addr); 363 return defaultPortID; 364 } 365 } else if (defaultPortID != InvalidPortID) { 366 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 367 "will use default port\n", addr); 368 return defaultPortID; 369 } 370 371 // we should use the range for the default port and it did not 372 // match, or the default port is not set 373 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 374 name()); 375} 376 377/** Function called by the port when the bus is receiving a range change.*/ 378void 379BaseBus::recvRangeChange(PortID master_port_id) 380{ 381 // remember that we got a range from this master port and thus the 382 // connected slave module 383 gotAddrRanges[master_port_id] = true; 384 385 // update the global flag 386 if (!gotAllAddrRanges) { 387 // take a logical AND of all the ports and see if we got 388 // ranges from everyone 389 gotAllAddrRanges = true; 390 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 391 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 392 gotAllAddrRanges &= *r++; 393 } 394 } 395 396 // note that we could get the range from the default port at any 397 // point in time, and we cannot assume that the default range is 398 // set before the other ones are, so we do additional checks once 399 // all ranges are provided 400 DPRINTF(BusAddrRanges, "received RangeChange from slave port %s\n", 401 masterPorts[master_port_id]->getSlavePort().name()); 402 403 if (master_port_id == defaultPortID) { 404 // only update if we are indeed checking ranges for the 405 // default port since the port might not have a valid range 406 // otherwise 407 if (useDefaultRange) { 408 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 409 410 if (ranges.size() != 1) 411 fatal("Bus %s may only have a single default range", 412 name()); 413 414 defaultRange = ranges.front(); 415 } 416 } else { 417 // the ports are allowed to update their address ranges 418 // dynamically, so remove any existing entries 419 if (gotAddrRanges[master_port_id]) { 420 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 421 if (p->second == master_port_id) 422 // erasing invalidates the iterator, so advance it 423 // before the deletion takes place 424 portMap.erase(p++); 425 else 426 p++; 427 } 428 } 429 430 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 431 432 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 433 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 434 r->to_string(), master_port_id); 435 if (portMap.insert(*r, master_port_id) == portMap.end()) { 436 PortID conflict_id = portMap.find(*r)->second; 437 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 438 name(), 439 masterPorts[master_port_id]->getSlavePort().name(), 440 masterPorts[conflict_id]->getSlavePort().name()); 441 } 442 } 443 } 444 445 // if we have received ranges from all our neighbouring slave 446 // modules, go ahead and tell our connected master modules in 447 // turn, this effectively assumes a tree structure of the system 448 if (gotAllAddrRanges) { 449 // also check that no range partially overlaps with the 450 // default range, this has to be done after all ranges are set 451 // as there are no guarantees for when the default range is 452 // update with respect to the other ones 453 if (useDefaultRange) { 454 for (PortID port_id = 0; port_id < masterPorts.size(); ++port_id) { 455 if (port_id == defaultPortID) { 456 if (!gotAddrRanges[port_id]) 457 fatal("Bus %s uses default range, but none provided", 458 name()); 459 } else { 460 AddrRangeList ranges = 461 masterPorts[port_id]->getAddrRanges(); 462 463 for (AddrRangeConstIter r = ranges.begin(); 464 r != ranges.end(); ++r) { 465 // see if the new range is partially 466 // overlapping the default range 467 if (r->intersects(defaultRange) && 468 !r->isSubset(defaultRange)) 469 fatal("Range %s intersects the " \ 470 "default range of %s but is not a " \ 471 "subset\n", r->to_string(), name()); 472 } 473 } 474 } 475 } 476 477 // tell all our neighbouring master ports that our address 478 // ranges have changed 479 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 480 ++s) 481 (*s)->sendRangeChange(); 482 } 483 484 clearPortCache(); 485} 486 487AddrRangeList 488BaseBus::getAddrRanges() const 489{ 490 // we should never be asked without first having sent a range 491 // change, and the latter is only done once we have all the ranges 492 // of the connected devices 493 assert(gotAllAddrRanges); 494 495 DPRINTF(BusAddrRanges, "received address range request, returning:\n"); 496 497 // start out with the default range 498 AddrRangeList ranges; 499 ranges.push_back(defaultRange); 500 DPRINTF(BusAddrRanges, " -- %s DEFAULT\n", defaultRange.to_string()); 501 502 // add any range that is not a subset of the default range 503 for (PortMapConstIter p = portMap.begin(); p != portMap.end(); ++p) { 504 if (useDefaultRange && p->first.isSubset(defaultRange)) { 505 DPRINTF(BusAddrRanges, " -- %s is a SUBSET\n", 506 p->first.to_string()); 507 } else { 508 ranges.push_back(p->first); 509 DPRINTF(BusAddrRanges, " -- %s\n", p->first.to_string()); 510 } 511 } 512 513 return ranges; 514} 515 516unsigned 517BaseBus::deviceBlockSize() const 518{ 519 return blockSize; 520} 521 522template <typename PortClass> 523unsigned int 524BaseBus::Layer<PortClass>::drain(DrainManager *dm) 525{ 526 //We should check that we're not "doing" anything, and that noone is 527 //waiting. We might be idle but have someone waiting if the device we 528 //contacted for a retry didn't actually retry. 529 if (!retryList.empty() || state != IDLE) { 530 DPRINTF(Drain, "Bus not drained\n"); 531 drainManager = dm; 532 return 1; 533 } 534 return 0; 535} 536 537/** 538 * Bus layer template instantiations. Could be removed with _impl.hh 539 * file, but since there are only two given options (MasterPort and 540 * SlavePort) it seems a bit excessive at this point. 541 */ 542template class BaseBus::Layer<SlavePort>; 543template class BaseBus::Layer<MasterPort>; 544