xbar.cc revision 10347
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{} 65 66BaseBus::~BaseBus() 67{ 68 for (MasterPortIter m = masterPorts.begin(); m != masterPorts.end(); 69 ++m) { 70 delete *m; 71 } 72 73 for (SlavePortIter s = slavePorts.begin(); s != slavePorts.end(); 74 ++s) { 75 delete *s; 76 } 77} 78 79void 80BaseBus::init() 81{ 82} 83 84BaseMasterPort & 85BaseBus::getMasterPort(const std::string &if_name, PortID idx) 86{ 87 if (if_name == "master" && idx < masterPorts.size()) { 88 // the master port index translates directly to the vector position 89 return *masterPorts[idx]; 90 } else if (if_name == "default") { 91 return *masterPorts[defaultPortID]; 92 } else { 93 return MemObject::getMasterPort(if_name, idx); 94 } 95} 96 97BaseSlavePort & 98BaseBus::getSlavePort(const std::string &if_name, PortID idx) 99{ 100 if (if_name == "slave" && idx < slavePorts.size()) { 101 // the slave port index translates directly to the vector position 102 return *slavePorts[idx]; 103 } else { 104 return MemObject::getSlavePort(if_name, idx); 105 } 106} 107 108void 109BaseBus::calcPacketTiming(PacketPtr pkt) 110{ 111 // the bus will be called at a time that is not necessarily 112 // coinciding with its own clock, so start by determining how long 113 // until the next clock edge (could be zero) 114 Tick offset = clockEdge() - curTick(); 115 116 // determine how many cycles are needed to send the data 117 unsigned dataCycles = pkt->hasData() ? divCeil(pkt->getSize(), width) : 0; 118 119 // before setting the bus delay fields of the packet, ensure that 120 // the delay from any previous bus has been accounted for 121 if (pkt->busFirstWordDelay != 0 || pkt->busLastWordDelay != 0) 122 panic("Packet %s already has bus delay (%d, %d) that should be " 123 "accounted for.\n", pkt->cmdString(), pkt->busFirstWordDelay, 124 pkt->busLastWordDelay); 125 126 // The first word will be delivered on the cycle after the header. 127 pkt->busFirstWordDelay = (headerCycles + 1) * clockPeriod() + offset; 128 129 // Note that currently busLastWordDelay can be smaller than 130 // busFirstWordDelay if the packet has no data 131 pkt->busLastWordDelay = (headerCycles + dataCycles) * clockPeriod() + 132 offset; 133} 134 135template <typename SrcType, typename DstType> 136BaseBus::Layer<SrcType,DstType>::Layer(DstType& _port, BaseBus& _bus, 137 const std::string& _name) : 138 port(_port), bus(_bus), _name(_name), state(IDLE), drainManager(NULL), 139 waitingForPeer(NULL), releaseEvent(this) 140{ 141} 142 143template <typename SrcType, typename DstType> 144void BaseBus::Layer<SrcType,DstType>::occupyLayer(Tick until) 145{ 146 // ensure the state is busy at this point, as the bus should 147 // transition from idle as soon as it has decided to forward the 148 // packet to prevent any follow-on calls to sendTiming seeing an 149 // unoccupied bus 150 assert(state == BUSY); 151 152 // until should never be 0 as express snoops never occupy the bus 153 assert(until != 0); 154 bus.schedule(releaseEvent, until); 155 156 // account for the occupied ticks 157 occupancy += until - curTick(); 158 159 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 160 curTick(), until); 161} 162 163template <typename SrcType, typename DstType> 164bool 165BaseBus::Layer<SrcType,DstType>::tryTiming(SrcType* src_port) 166{ 167 // if we are in the retry state, we will not see anything but the 168 // retrying port (or in the case of the snoop ports the snoop 169 // response port that mirrors the actual slave port) as we leave 170 // this state again in zero time if the peer does not immediately 171 // call the bus when receiving the retry 172 173 // first we see if the layer is busy, next we check if the 174 // destination port is already engaged in a transaction waiting 175 // for a retry from the peer 176 if (state == BUSY || waitingForPeer != NULL) { 177 // the port should not be waiting already 178 assert(std::find(waitingForLayer.begin(), waitingForLayer.end(), 179 src_port) == waitingForLayer.end()); 180 181 // put the port at the end of the retry list waiting for the 182 // layer to be freed up (and in the case of a busy peer, for 183 // that transaction to go through, and then the bus to free 184 // up) 185 waitingForLayer.push_back(src_port); 186 return false; 187 } 188 189 // update the state to busy 190 state = BUSY; 191 192 return true; 193} 194 195template <typename SrcType, typename DstType> 196void 197BaseBus::Layer<SrcType,DstType>::succeededTiming(Tick busy_time) 198{ 199 // we should have gone from idle or retry to busy in the tryTiming 200 // test 201 assert(state == BUSY); 202 203 // occupy the bus accordingly 204 occupyLayer(busy_time); 205} 206 207template <typename SrcType, typename DstType> 208void 209BaseBus::Layer<SrcType,DstType>::failedTiming(SrcType* src_port, 210 Tick busy_time) 211{ 212 // ensure no one got in between and tried to send something to 213 // this port 214 assert(waitingForPeer == NULL); 215 216 // if the source port is the current retrying one or not, we have 217 // failed in forwarding and should track that we are now waiting 218 // for the peer to send a retry 219 waitingForPeer = src_port; 220 221 // we should have gone from idle or retry to busy in the tryTiming 222 // test 223 assert(state == BUSY); 224 225 // occupy the bus accordingly 226 occupyLayer(busy_time); 227} 228 229template <typename SrcType, typename DstType> 230void 231BaseBus::Layer<SrcType,DstType>::releaseLayer() 232{ 233 // releasing the bus means we should now be idle 234 assert(state == BUSY); 235 assert(!releaseEvent.scheduled()); 236 237 // update the state 238 state = IDLE; 239 240 // bus layer is now idle, so if someone is waiting we can retry 241 if (!waitingForLayer.empty()) { 242 // there is no point in sending a retry if someone is still 243 // waiting for the peer 244 if (waitingForPeer == NULL) 245 retryWaiting(); 246 } else if (waitingForPeer == NULL && drainManager) { 247 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 248 //If we weren't able to drain before, do it now. 249 drainManager->signalDrainDone(); 250 // Clear the drain event once we're done with it. 251 drainManager = NULL; 252 } 253} 254 255template <typename SrcType, typename DstType> 256void 257BaseBus::Layer<SrcType,DstType>::retryWaiting() 258{ 259 // this should never be called with no one waiting 260 assert(!waitingForLayer.empty()); 261 262 // we always go to retrying from idle 263 assert(state == IDLE); 264 265 // update the state 266 state = RETRY; 267 268 // set the retrying port to the front of the retry list and pop it 269 // off the list 270 SrcType* retryingPort = waitingForLayer.front(); 271 waitingForLayer.pop_front(); 272 273 // tell the port to retry, which in some cases ends up calling the 274 // bus 275 retryingPort->sendRetry(); 276 277 // If the bus is still in the retry state, sendTiming wasn't 278 // called in zero time (e.g. the cache does this), burn a cycle 279 if (state == RETRY) { 280 // update the state to busy and reset the retrying port, we 281 // have done our bit and sent the retry 282 state = BUSY; 283 284 // occupy the bus layer until the next cycle ends 285 occupyLayer(bus.clockEdge(Cycles(1))); 286 } 287} 288 289template <typename SrcType, typename DstType> 290void 291BaseBus::Layer<SrcType,DstType>::recvRetry() 292{ 293 // we should never get a retry without having failed to forward 294 // something to this port 295 assert(waitingForPeer != NULL); 296 297 // add the port where the failed packet originated to the front of 298 // the waiting ports for the layer, this allows us to call retry 299 // on the port immediately if the bus layer is idle 300 waitingForLayer.push_front(waitingForPeer); 301 302 // we are no longer waiting for the peer 303 waitingForPeer = NULL; 304 305 // if the bus layer is idle, retry this port straight away, if we 306 // are busy, then simply let the port wait for its turn 307 if (state == IDLE) { 308 retryWaiting(); 309 } else { 310 assert(state == BUSY); 311 } 312} 313 314PortID 315BaseBus::findPort(Addr addr) 316{ 317 // we should never see any address lookups before we've got the 318 // ranges of all connected slave modules 319 assert(gotAllAddrRanges); 320 321 // Check the cache 322 PortID dest_id = checkPortCache(addr); 323 if (dest_id != InvalidPortID) 324 return dest_id; 325 326 // Check the address map interval tree 327 PortMapConstIter i = portMap.find(addr); 328 if (i != portMap.end()) { 329 dest_id = i->second; 330 updatePortCache(dest_id, i->first); 331 return dest_id; 332 } 333 334 // Check if this matches the default range 335 if (useDefaultRange) { 336 if (defaultRange.contains(addr)) { 337 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 338 addr); 339 return defaultPortID; 340 } 341 } else if (defaultPortID != InvalidPortID) { 342 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 343 "will use default port\n", addr); 344 return defaultPortID; 345 } 346 347 // we should use the range for the default port and it did not 348 // match, or the default port is not set 349 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 350 name()); 351} 352 353/** Function called by the port when the bus is receiving a range change.*/ 354void 355BaseBus::recvRangeChange(PortID master_port_id) 356{ 357 DPRINTF(BusAddrRanges, "Received range change from slave port %s\n", 358 masterPorts[master_port_id]->getSlavePort().name()); 359 360 // remember that we got a range from this master port and thus the 361 // connected slave module 362 gotAddrRanges[master_port_id] = true; 363 364 // update the global flag 365 if (!gotAllAddrRanges) { 366 // take a logical AND of all the ports and see if we got 367 // ranges from everyone 368 gotAllAddrRanges = true; 369 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 370 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 371 gotAllAddrRanges &= *r++; 372 } 373 if (gotAllAddrRanges) 374 DPRINTF(BusAddrRanges, "Got address ranges from all slaves\n"); 375 } 376 377 // note that we could get the range from the default port at any 378 // point in time, and we cannot assume that the default range is 379 // set before the other ones are, so we do additional checks once 380 // all ranges are provided 381 if (master_port_id == defaultPortID) { 382 // only update if we are indeed checking ranges for the 383 // default port since the port might not have a valid range 384 // otherwise 385 if (useDefaultRange) { 386 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 387 388 if (ranges.size() != 1) 389 fatal("Bus %s may only have a single default range", 390 name()); 391 392 defaultRange = ranges.front(); 393 } 394 } else { 395 // the ports are allowed to update their address ranges 396 // dynamically, so remove any existing entries 397 if (gotAddrRanges[master_port_id]) { 398 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 399 if (p->second == master_port_id) 400 // erasing invalidates the iterator, so advance it 401 // before the deletion takes place 402 portMap.erase(p++); 403 else 404 p++; 405 } 406 } 407 408 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 409 410 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 411 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 412 r->to_string(), master_port_id); 413 if (portMap.insert(*r, master_port_id) == portMap.end()) { 414 PortID conflict_id = portMap.find(*r)->second; 415 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 416 name(), 417 masterPorts[master_port_id]->getSlavePort().name(), 418 masterPorts[conflict_id]->getSlavePort().name()); 419 } 420 } 421 } 422 423 // if we have received ranges from all our neighbouring slave 424 // modules, go ahead and tell our connected master modules in 425 // turn, this effectively assumes a tree structure of the system 426 if (gotAllAddrRanges) { 427 DPRINTF(BusAddrRanges, "Aggregating bus ranges\n"); 428 busRanges.clear(); 429 430 // start out with the default range 431 if (useDefaultRange) { 432 if (!gotAddrRanges[defaultPortID]) 433 fatal("Bus %s uses default range, but none provided", 434 name()); 435 436 busRanges.push_back(defaultRange); 437 DPRINTF(BusAddrRanges, "-- Adding default %s\n", 438 defaultRange.to_string()); 439 } 440 441 // merge all interleaved ranges and add any range that is not 442 // a subset of the default range 443 std::vector<AddrRange> intlv_ranges; 444 for (AddrRangeMap<PortID>::const_iterator r = portMap.begin(); 445 r != portMap.end(); ++r) { 446 // if the range is interleaved then save it for now 447 if (r->first.interleaved()) { 448 // if we already got interleaved ranges that are not 449 // part of the same range, then first do a merge 450 // before we add the new one 451 if (!intlv_ranges.empty() && 452 !intlv_ranges.back().mergesWith(r->first)) { 453 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 454 intlv_ranges.size()); 455 AddrRange merged_range(intlv_ranges); 456 // next decide if we keep the merged range or not 457 if (!(useDefaultRange && 458 merged_range.isSubset(defaultRange))) { 459 busRanges.push_back(merged_range); 460 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 461 merged_range.to_string()); 462 } 463 intlv_ranges.clear(); 464 } 465 intlv_ranges.push_back(r->first); 466 } else { 467 // keep the current range if not a subset of the default 468 if (!(useDefaultRange && 469 r->first.isSubset(defaultRange))) { 470 busRanges.push_back(r->first); 471 DPRINTF(BusAddrRanges, "-- Adding range %s\n", 472 r->first.to_string()); 473 } 474 } 475 } 476 477 // if there is still interleaved ranges waiting to be merged, 478 // go ahead and do it 479 if (!intlv_ranges.empty()) { 480 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 481 intlv_ranges.size()); 482 AddrRange merged_range(intlv_ranges); 483 if (!(useDefaultRange && merged_range.isSubset(defaultRange))) { 484 busRanges.push_back(merged_range); 485 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 486 merged_range.to_string()); 487 } 488 } 489 490 // also check that no range partially overlaps with the 491 // default range, this has to be done after all ranges are set 492 // as there are no guarantees for when the default range is 493 // update with respect to the other ones 494 if (useDefaultRange) { 495 for (AddrRangeConstIter r = busRanges.begin(); 496 r != busRanges.end(); ++r) { 497 // see if the new range is partially 498 // overlapping the default range 499 if (r->intersects(defaultRange) && 500 !r->isSubset(defaultRange)) 501 fatal("Range %s intersects the " \ 502 "default range of %s but is not a " \ 503 "subset\n", r->to_string(), name()); 504 } 505 } 506 507 // tell all our neighbouring master ports that our address 508 // ranges have changed 509 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 510 ++s) 511 (*s)->sendRangeChange(); 512 } 513 514 clearPortCache(); 515} 516 517AddrRangeList 518BaseBus::getAddrRanges() const 519{ 520 // we should never be asked without first having sent a range 521 // change, and the latter is only done once we have all the ranges 522 // of the connected devices 523 assert(gotAllAddrRanges); 524 525 // at the moment, this never happens, as there are no cycles in 526 // the range queries and no devices on the master side of a bus 527 // (CPU, cache, bridge etc) actually care about the ranges of the 528 // ports they are connected to 529 530 DPRINTF(BusAddrRanges, "Received address range request\n"); 531 532 return busRanges; 533} 534 535void 536BaseBus::regStats() 537{ 538 using namespace Stats; 539 540 transDist 541 .init(MemCmd::NUM_MEM_CMDS) 542 .name(name() + ".trans_dist") 543 .desc("Transaction distribution") 544 .flags(nozero); 545 546 // get the string representation of the commands 547 for (int i = 0; i < MemCmd::NUM_MEM_CMDS; i++) { 548 MemCmd cmd(i); 549 const std::string &cstr = cmd.toString(); 550 transDist.subname(i, cstr); 551 } 552 553 pktCount 554 .init(slavePorts.size(), masterPorts.size()) 555 .name(name() + ".pkt_count") 556 .desc("Packet count per connected master and slave (bytes)") 557 .flags(total | nozero | nonan); 558 559 totPktSize 560 .init(slavePorts.size(), masterPorts.size()) 561 .name(name() + ".tot_pkt_size") 562 .desc("Cumulative packet size per connected master and slave (bytes)") 563 .flags(total | nozero | nonan); 564 565 // both the packet count and total size are two-dimensional 566 // vectors, indexed by slave port id and master port id, thus the 567 // neighbouring master and slave, they do not differentiate what 568 // came from the master and was forwarded to the slave (requests 569 // and snoop responses) and what came from the slave and was 570 // forwarded to the master (responses and snoop requests) 571 for (int i = 0; i < slavePorts.size(); i++) { 572 pktCount.subname(i, slavePorts[i]->getMasterPort().name()); 573 totPktSize.subname(i, slavePorts[i]->getMasterPort().name()); 574 for (int j = 0; j < masterPorts.size(); j++) { 575 pktCount.ysubname(j, masterPorts[j]->getSlavePort().name()); 576 totPktSize.ysubname(j, masterPorts[j]->getSlavePort().name()); 577 } 578 } 579} 580 581template <typename SrcType, typename DstType> 582unsigned int 583BaseBus::Layer<SrcType,DstType>::drain(DrainManager *dm) 584{ 585 //We should check that we're not "doing" anything, and that noone is 586 //waiting. We might be idle but have someone waiting if the device we 587 //contacted for a retry didn't actually retry. 588 if (state != IDLE) { 589 DPRINTF(Drain, "Bus not drained\n"); 590 drainManager = dm; 591 return 1; 592 } 593 return 0; 594} 595 596template <typename SrcType, typename DstType> 597void 598BaseBus::Layer<SrcType,DstType>::regStats() 599{ 600 using namespace Stats; 601 602 occupancy 603 .name(name() + ".occupancy") 604 .desc("Layer occupancy (ticks)") 605 .flags(nozero); 606 607 utilization 608 .name(name() + ".utilization") 609 .desc("Layer utilization (%)") 610 .precision(1) 611 .flags(nozero); 612 613 utilization = 100 * occupancy / simTicks; 614} 615 616/** 617 * Bus layer template instantiations. Could be removed with _impl.hh 618 * file, but since there are only two given options (MasterPort and 619 * SlavePort) it seems a bit excessive at this point. 620 */ 621template class BaseBus::Layer<SlavePort,MasterPort>; 622template class BaseBus::Layer<MasterPort,SlavePort>; 623