xbar.cc revision 9716
1/* 2 * Copyright (c) 2011-2013 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 132void 133BaseBus::calcPacketTiming(PacketPtr pkt) 134{ 135 // the bus will be called at a time that is not necessarily 136 // coinciding with its own clock, so start by determining how long 137 // until the next clock edge (could be zero) 138 Tick offset = clockEdge() - curTick(); 139 140 // determine how many cycles are needed to send the data 141 unsigned dataCycles = pkt->hasData() ? divCeil(pkt->getSize(), width) : 0; 142 143 // before setting the bus delay fields of the packet, ensure that 144 // the delay from any previous bus has been accounted for 145 if (pkt->busFirstWordDelay != 0 || pkt->busLastWordDelay != 0) 146 panic("Packet %s already has bus delay (%d, %d) that should be " 147 "accounted for.\n", pkt->cmdString(), pkt->busFirstWordDelay, 148 pkt->busLastWordDelay); 149 150 // The first word will be delivered on the cycle after the header. 151 pkt->busFirstWordDelay = (headerCycles + 1) * clockPeriod() + offset; 152 153 // Note that currently busLastWordDelay can be smaller than 154 // busFirstWordDelay if the packet has no data 155 pkt->busLastWordDelay = (headerCycles + dataCycles) * clockPeriod() + 156 offset; 157} 158 159template <typename SrcType, typename DstType> 160BaseBus::Layer<SrcType,DstType>::Layer(DstType& _port, BaseBus& _bus, 161 const std::string& _name) : 162 port(_port), bus(_bus), _name(_name), state(IDLE), drainManager(NULL), 163 retryingPort(NULL), waitingForPeer(NULL), 164 releaseEvent(this) 165{ 166} 167 168template <typename SrcType, typename DstType> 169void BaseBus::Layer<SrcType,DstType>::occupyLayer(Tick until) 170{ 171 // ensure the state is busy at this point, as the bus should 172 // transition from idle as soon as it has decided to forward the 173 // packet to prevent any follow-on calls to sendTiming seeing an 174 // unoccupied bus 175 assert(state == BUSY); 176 177 // until should never be 0 as express snoops never occupy the bus 178 assert(until != 0); 179 bus.schedule(releaseEvent, until); 180 181 // account for the occupied ticks 182 occupancy += until - curTick(); 183 184 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 185 curTick(), until); 186} 187 188template <typename SrcType, typename DstType> 189bool 190BaseBus::Layer<SrcType,DstType>::tryTiming(SrcType* src_port) 191{ 192 // if we are in the retry state, we will not see anything but the 193 // retrying port (or in the case of the snoop ports the snoop 194 // response port that mirrors the actual slave port) as we leave 195 // this state again in zero time if the peer does not immediately 196 // call the bus when receiving the retry 197 198 // first we see if the layer is busy, next we check if the 199 // destination port is already engaged in a transaction waiting 200 // for a retry from the peer 201 if (state == BUSY || waitingForPeer != NULL) { 202 // the port should not be waiting already 203 assert(std::find(waitingForLayer.begin(), waitingForLayer.end(), 204 src_port) == waitingForLayer.end()); 205 206 // put the port at the end of the retry list waiting for the 207 // layer to be freed up (and in the case of a busy peer, for 208 // that transaction to go through, and then the bus to free 209 // up) 210 waitingForLayer.push_back(src_port); 211 return false; 212 } 213 214 // update the state to busy 215 state = BUSY; 216 217 // reset the retrying port 218 retryingPort = NULL; 219 220 return true; 221} 222 223template <typename SrcType, typename DstType> 224void 225BaseBus::Layer<SrcType,DstType>::succeededTiming(Tick busy_time) 226{ 227 // we should have gone from idle or retry to busy in the tryTiming 228 // test 229 assert(state == BUSY); 230 231 // occupy the bus accordingly 232 occupyLayer(busy_time); 233} 234 235template <typename SrcType, typename DstType> 236void 237BaseBus::Layer<SrcType,DstType>::failedTiming(SrcType* src_port, 238 Tick busy_time) 239{ 240 // ensure no one got in between and tried to send something to 241 // this port 242 assert(waitingForPeer == NULL); 243 244 // if the source port is the current retrying one or not, we have 245 // failed in forwarding and should track that we are now waiting 246 // for the peer to send a retry 247 waitingForPeer = src_port; 248 249 // we should have gone from idle or retry to busy in the tryTiming 250 // test 251 assert(state == BUSY); 252 253 // occupy the bus accordingly 254 occupyLayer(busy_time); 255} 256 257template <typename SrcType, typename DstType> 258void 259BaseBus::Layer<SrcType,DstType>::releaseLayer() 260{ 261 // releasing the bus means we should now be idle 262 assert(state == BUSY); 263 assert(!releaseEvent.scheduled()); 264 265 // update the state 266 state = IDLE; 267 268 // bus layer is now idle, so if someone is waiting we can retry 269 if (!waitingForLayer.empty()) { 270 retryWaiting(); 271 } else if (waitingForPeer == NULL && drainManager) { 272 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 273 //If we weren't able to drain before, do it now. 274 drainManager->signalDrainDone(); 275 // Clear the drain event once we're done with it. 276 drainManager = NULL; 277 } 278} 279 280template <typename SrcType, typename DstType> 281void 282BaseBus::Layer<SrcType,DstType>::retryWaiting() 283{ 284 // this should never be called with no one waiting 285 assert(!waitingForLayer.empty()); 286 287 // we always go to retrying from idle 288 assert(state == IDLE); 289 290 // update the state 291 state = RETRY; 292 293 // set the retrying port to the front of the retry list and pop it 294 // off the list 295 assert(retryingPort == NULL); 296 retryingPort = waitingForLayer.front(); 297 waitingForLayer.pop_front(); 298 299 // tell the port to retry, which in some cases ends up calling the 300 // bus 301 retryingPort->sendRetry(); 302 303 // If the bus is still in the retry state, sendTiming wasn't 304 // called in zero time (e.g. the cache does this), burn a cycle 305 if (state == RETRY) { 306 // update the state to busy and reset the retrying port, we 307 // have done our bit and sent the retry 308 state = BUSY; 309 retryingPort = NULL; 310 311 // occupy the bus layer until the next cycle ends 312 occupyLayer(bus.clockEdge(Cycles(1))); 313 } 314} 315 316template <typename SrcType, typename DstType> 317void 318BaseBus::Layer<SrcType,DstType>::recvRetry() 319{ 320 // we should never get a retry without having failed to forward 321 // something to this port 322 assert(waitingForPeer != NULL); 323 324 // add the port where the failed packet originated to the front of 325 // the waiting ports for the layer, this allows us to call retry 326 // on the port immediately if the bus layer is idle 327 waitingForLayer.push_front(waitingForPeer); 328 329 // we are no longer waiting for the peer 330 waitingForPeer = NULL; 331 332 // if the bus layer is idle, retry this port straight away, if we 333 // are busy, then simply let the port wait for its turn 334 if (state == IDLE) { 335 retryWaiting(); 336 } else { 337 assert(state == BUSY); 338 } 339} 340 341PortID 342BaseBus::findPort(Addr addr) 343{ 344 // we should never see any address lookups before we've got the 345 // ranges of all connected slave modules 346 assert(gotAllAddrRanges); 347 348 // Check the cache 349 PortID dest_id = checkPortCache(addr); 350 if (dest_id != InvalidPortID) 351 return dest_id; 352 353 // Check the address map interval tree 354 PortMapConstIter i = portMap.find(addr); 355 if (i != portMap.end()) { 356 dest_id = i->second; 357 updatePortCache(dest_id, i->first); 358 return dest_id; 359 } 360 361 // Check if this matches the default range 362 if (useDefaultRange) { 363 if (defaultRange.contains(addr)) { 364 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 365 addr); 366 return defaultPortID; 367 } 368 } else if (defaultPortID != InvalidPortID) { 369 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 370 "will use default port\n", addr); 371 return defaultPortID; 372 } 373 374 // we should use the range for the default port and it did not 375 // match, or the default port is not set 376 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 377 name()); 378} 379 380/** Function called by the port when the bus is receiving a range change.*/ 381void 382BaseBus::recvRangeChange(PortID master_port_id) 383{ 384 DPRINTF(BusAddrRanges, "Received range change from slave port %s\n", 385 masterPorts[master_port_id]->getSlavePort().name()); 386 387 // remember that we got a range from this master port and thus the 388 // connected slave module 389 gotAddrRanges[master_port_id] = true; 390 391 // update the global flag 392 if (!gotAllAddrRanges) { 393 // take a logical AND of all the ports and see if we got 394 // ranges from everyone 395 gotAllAddrRanges = true; 396 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 397 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 398 gotAllAddrRanges &= *r++; 399 } 400 if (gotAllAddrRanges) 401 DPRINTF(BusAddrRanges, "Got address ranges from all slaves\n"); 402 } 403 404 // note that we could get the range from the default port at any 405 // point in time, and we cannot assume that the default range is 406 // set before the other ones are, so we do additional checks once 407 // all ranges are provided 408 if (master_port_id == defaultPortID) { 409 // only update if we are indeed checking ranges for the 410 // default port since the port might not have a valid range 411 // otherwise 412 if (useDefaultRange) { 413 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 414 415 if (ranges.size() != 1) 416 fatal("Bus %s may only have a single default range", 417 name()); 418 419 defaultRange = ranges.front(); 420 } 421 } else { 422 // the ports are allowed to update their address ranges 423 // dynamically, so remove any existing entries 424 if (gotAddrRanges[master_port_id]) { 425 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 426 if (p->second == master_port_id) 427 // erasing invalidates the iterator, so advance it 428 // before the deletion takes place 429 portMap.erase(p++); 430 else 431 p++; 432 } 433 } 434 435 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 436 437 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 438 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 439 r->to_string(), master_port_id); 440 if (portMap.insert(*r, master_port_id) == portMap.end()) { 441 PortID conflict_id = portMap.find(*r)->second; 442 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 443 name(), 444 masterPorts[master_port_id]->getSlavePort().name(), 445 masterPorts[conflict_id]->getSlavePort().name()); 446 } 447 } 448 } 449 450 // if we have received ranges from all our neighbouring slave 451 // modules, go ahead and tell our connected master modules in 452 // turn, this effectively assumes a tree structure of the system 453 if (gotAllAddrRanges) { 454 DPRINTF(BusAddrRanges, "Aggregating bus ranges\n"); 455 busRanges.clear(); 456 457 // start out with the default range 458 if (useDefaultRange) { 459 if (!gotAddrRanges[defaultPortID]) 460 fatal("Bus %s uses default range, but none provided", 461 name()); 462 463 busRanges.push_back(defaultRange); 464 DPRINTF(BusAddrRanges, "-- Adding default %s\n", 465 defaultRange.to_string()); 466 } 467 468 // merge all interleaved ranges and add any range that is not 469 // a subset of the default range 470 std::vector<AddrRange> intlv_ranges; 471 for (AddrRangeMap<PortID>::const_iterator r = portMap.begin(); 472 r != portMap.end(); ++r) { 473 // if the range is interleaved then save it for now 474 if (r->first.interleaved()) { 475 // if we already got interleaved ranges that are not 476 // part of the same range, then first do a merge 477 // before we add the new one 478 if (!intlv_ranges.empty() && 479 !intlv_ranges.back().mergesWith(r->first)) { 480 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 481 intlv_ranges.size()); 482 AddrRange merged_range(intlv_ranges); 483 // next decide if we keep the merged range or not 484 if (!(useDefaultRange && 485 merged_range.isSubset(defaultRange))) { 486 busRanges.push_back(merged_range); 487 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 488 merged_range.to_string()); 489 } 490 intlv_ranges.clear(); 491 } 492 intlv_ranges.push_back(r->first); 493 } else { 494 // keep the current range if not a subset of the default 495 if (!(useDefaultRange && 496 r->first.isSubset(defaultRange))) { 497 busRanges.push_back(r->first); 498 DPRINTF(BusAddrRanges, "-- Adding range %s\n", 499 r->first.to_string()); 500 } 501 } 502 } 503 504 // if there is still interleaved ranges waiting to be merged, 505 // go ahead and do it 506 if (!intlv_ranges.empty()) { 507 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 508 intlv_ranges.size()); 509 AddrRange merged_range(intlv_ranges); 510 if (!(useDefaultRange && merged_range.isSubset(defaultRange))) { 511 busRanges.push_back(merged_range); 512 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 513 merged_range.to_string()); 514 } 515 } 516 517 // also check that no range partially overlaps with the 518 // default range, this has to be done after all ranges are set 519 // as there are no guarantees for when the default range is 520 // update with respect to the other ones 521 if (useDefaultRange) { 522 for (AddrRangeConstIter r = busRanges.begin(); 523 r != busRanges.end(); ++r) { 524 // see if the new range is partially 525 // overlapping the default range 526 if (r->intersects(defaultRange) && 527 !r->isSubset(defaultRange)) 528 fatal("Range %s intersects the " \ 529 "default range of %s but is not a " \ 530 "subset\n", r->to_string(), name()); 531 } 532 } 533 534 // tell all our neighbouring master ports that our address 535 // ranges have changed 536 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 537 ++s) 538 (*s)->sendRangeChange(); 539 } 540 541 clearPortCache(); 542} 543 544AddrRangeList 545BaseBus::getAddrRanges() const 546{ 547 // we should never be asked without first having sent a range 548 // change, and the latter is only done once we have all the ranges 549 // of the connected devices 550 assert(gotAllAddrRanges); 551 552 // at the moment, this never happens, as there are no cycles in 553 // the range queries and no devices on the master side of a bus 554 // (CPU, cache, bridge etc) actually care about the ranges of the 555 // ports they are connected to 556 557 DPRINTF(BusAddrRanges, "Received address range request\n"); 558 559 return busRanges; 560} 561 562unsigned 563BaseBus::deviceBlockSize() const 564{ 565 return blockSize; 566} 567 568void 569BaseBus::regStats() 570{ 571 using namespace Stats; 572 573 transDist 574 .init(MemCmd::NUM_MEM_CMDS) 575 .name(name() + ".trans_dist") 576 .desc("Transaction distribution") 577 .flags(nozero); 578 579 // get the string representation of the commands 580 for (int i = 0; i < MemCmd::NUM_MEM_CMDS; i++) { 581 MemCmd cmd(i); 582 const std::string &cstr = cmd.toString(); 583 transDist.subname(i, cstr); 584 } 585 586 pktCount 587 .init(slavePorts.size(), masterPorts.size()) 588 .name(name() + ".pkt_count") 589 .desc("Packet count per connected master and slave (bytes)") 590 .flags(total | nozero | nonan); 591 592 totPktSize 593 .init(slavePorts.size(), masterPorts.size()) 594 .name(name() + ".tot_pkt_size") 595 .desc("Cumulative packet size per connected master and slave (bytes)") 596 .flags(total | nozero | nonan); 597 598 // both the packet count and total size are two-dimensional 599 // vectors, indexed by slave port id and master port id, thus the 600 // neighbouring master and slave, they do not differentiate what 601 // came from the master and was forwarded to the slave (requests 602 // and snoop responses) and what came from the slave and was 603 // forwarded to the master (responses and snoop requests) 604 for (int i = 0; i < slavePorts.size(); i++) { 605 pktCount.subname(i, slavePorts[i]->getMasterPort().name()); 606 totPktSize.subname(i, slavePorts[i]->getMasterPort().name()); 607 for (int j = 0; j < masterPorts.size(); j++) { 608 pktCount.ysubname(j, masterPorts[j]->getSlavePort().name()); 609 totPktSize.ysubname(j, masterPorts[j]->getSlavePort().name()); 610 } 611 } 612} 613 614template <typename SrcType, typename DstType> 615unsigned int 616BaseBus::Layer<SrcType,DstType>::drain(DrainManager *dm) 617{ 618 //We should check that we're not "doing" anything, and that noone is 619 //waiting. We might be idle but have someone waiting if the device we 620 //contacted for a retry didn't actually retry. 621 if (state != IDLE) { 622 DPRINTF(Drain, "Bus not drained\n"); 623 drainManager = dm; 624 return 1; 625 } 626 return 0; 627} 628 629template <typename SrcType, typename DstType> 630void 631BaseBus::Layer<SrcType,DstType>::regStats() 632{ 633 using namespace Stats; 634 635 occupancy 636 .name(name() + ".occupancy") 637 .desc("Layer occupancy (ticks)") 638 .flags(nozero); 639 640 utilization 641 .name(name() + ".utilization") 642 .desc("Layer utilization (%)") 643 .precision(1) 644 .flags(nozero); 645 646 utilization = 100 * occupancy / simTicks; 647} 648 649/** 650 * Bus layer template instantiations. Could be removed with _impl.hh 651 * file, but since there are only two given options (MasterPort and 652 * SlavePort) it seems a bit excessive at this point. 653 */ 654template class BaseBus::Layer<SlavePort,MasterPort>; 655template class BaseBus::Layer<MasterPort,SlavePort>; 656