xbar.cc revision 9612
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 = nextCycle() - 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 PortClass> 160BaseBus::Layer<PortClass>::Layer(BaseBus& _bus, const std::string& _name, 161 uint16_t num_dest_ports) : 162 Drainable(), 163 bus(_bus), _name(_name), state(IDLE), drainManager(NULL), 164 retryingPort(NULL), waitingForPeer(num_dest_ports, NULL), 165 releaseEvent(this) 166{ 167} 168 169template <typename PortClass> 170void BaseBus::Layer<PortClass>::occupyLayer(Tick until) 171{ 172 // ensure the state is busy at this point, as the bus should 173 // transition from idle as soon as it has decided to forward the 174 // packet to prevent any follow-on calls to sendTiming seeing an 175 // unoccupied bus 176 assert(state == BUSY); 177 178 // until should never be 0 as express snoops never occupy the bus 179 assert(until != 0); 180 bus.schedule(releaseEvent, until); 181 182 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 183 curTick(), until); 184} 185 186template <typename PortClass> 187bool 188BaseBus::Layer<PortClass>::tryTiming(PortClass* port, PortID dest_port_id) 189{ 190 // first we see if the bus is busy, next we check if we are in a 191 // retry with a port other than the current one, lastly we check 192 // if the destination port is already engaged in a transaction 193 // waiting for a retry from the peer 194 if (state == BUSY || (state == RETRY && port != retryingPort) || 195 (dest_port_id != InvalidPortID && 196 waitingForPeer[dest_port_id] != NULL)) { 197 // put the port at the end of the retry list waiting for the 198 // layer to be freed up (and in the case of a busy peer, for 199 // that transaction to go through, and then the bus to free 200 // up) 201 waitingForLayer.push_back(port); 202 return false; 203 } 204 205 // update the state to busy 206 state = BUSY; 207 208 // reset the retrying port 209 retryingPort = NULL; 210 211 return true; 212} 213 214template <typename PortClass> 215void 216BaseBus::Layer<PortClass>::succeededTiming(Tick busy_time) 217{ 218 // we should have gone from idle or retry to busy in the tryTiming 219 // test 220 assert(state == BUSY); 221 222 // occupy the bus accordingly 223 occupyLayer(busy_time); 224} 225 226template <typename PortClass> 227void 228BaseBus::Layer<PortClass>::failedTiming(PortClass* src_port, 229 PortID dest_port_id, Tick busy_time) 230{ 231 // ensure no one got in between and tried to send something to 232 // this port 233 assert(waitingForPeer[dest_port_id] == NULL); 234 235 // if the source port is the current retrying one or not, we have 236 // failed in forwarding and should track that we are now waiting 237 // for the peer to send a retry 238 waitingForPeer[dest_port_id] = src_port; 239 240 // we should have gone from idle or retry to busy in the tryTiming 241 // test 242 assert(state == BUSY); 243 244 // occupy the bus accordingly 245 occupyLayer(busy_time); 246} 247 248template <typename PortClass> 249void 250BaseBus::Layer<PortClass>::releaseLayer() 251{ 252 // releasing the bus means we should now be idle 253 assert(state == BUSY); 254 assert(!releaseEvent.scheduled()); 255 256 // update the state 257 state = IDLE; 258 259 // bus layer is now idle, so if someone is waiting we can retry 260 if (!waitingForLayer.empty()) { 261 retryWaiting(); 262 } else if (drainManager) { 263 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 264 //If we weren't able to drain before, do it now. 265 drainManager->signalDrainDone(); 266 // Clear the drain event once we're done with it. 267 drainManager = NULL; 268 } 269} 270 271template <typename PortClass> 272void 273BaseBus::Layer<PortClass>::retryWaiting() 274{ 275 // this should never be called with no one waiting 276 assert(!waitingForLayer.empty()); 277 278 // we always go to retrying from idle 279 assert(state == IDLE); 280 281 // update the state 282 state = RETRY; 283 284 // set the retrying port to the front of the retry list and pop it 285 // off the list 286 assert(retryingPort == NULL); 287 retryingPort = waitingForLayer.front(); 288 waitingForLayer.pop_front(); 289 290 // tell the port to retry, which in some cases ends up calling the 291 // bus 292 retryingPort->sendRetry(); 293 294 // If the bus is still in the retry state, sendTiming wasn't 295 // called in zero time (e.g. the cache does this), burn a cycle 296 if (state == RETRY) { 297 // update the state to busy and reset the retrying port, we 298 // have done our bit and sent the retry 299 state = BUSY; 300 retryingPort = NULL; 301 302 // occupy the bus layer until the next cycle ends 303 occupyLayer(bus.clockEdge(Cycles(1))); 304 } 305} 306 307template <typename PortClass> 308void 309BaseBus::Layer<PortClass>::recvRetry(PortID port_id) 310{ 311 // we should never get a retry without having failed to forward 312 // something to this port 313 assert(waitingForPeer[port_id] != NULL); 314 315 // find the port where the failed packet originated and remove the 316 // item from the waiting list 317 PortClass* retry_port = waitingForPeer[port_id]; 318 waitingForPeer[port_id] = NULL; 319 320 // add this port at the front of the waiting ports for the layer, 321 // this allows us to call retry on the port immediately if the bus 322 // layer is idle 323 waitingForLayer.push_front(retry_port); 324 325 // if the bus layer is idle, retry this port straight away, if we 326 // are busy, then simply let the port wait for its turn 327 if (state == IDLE) { 328 retryWaiting(); 329 } else { 330 assert(state == BUSY); 331 } 332} 333 334PortID 335BaseBus::findPort(Addr addr) 336{ 337 // we should never see any address lookups before we've got the 338 // ranges of all connected slave modules 339 assert(gotAllAddrRanges); 340 341 // Check the cache 342 PortID dest_id = checkPortCache(addr); 343 if (dest_id != InvalidPortID) 344 return dest_id; 345 346 // Check the address map interval tree 347 PortMapConstIter i = portMap.find(addr); 348 if (i != portMap.end()) { 349 dest_id = i->second; 350 updatePortCache(dest_id, i->first); 351 return dest_id; 352 } 353 354 // Check if this matches the default range 355 if (useDefaultRange) { 356 if (defaultRange.contains(addr)) { 357 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 358 addr); 359 return defaultPortID; 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 DPRINTF(BusAddrRanges, "Received range change from slave port %s\n", 378 masterPorts[master_port_id]->getSlavePort().name()); 379 380 // remember that we got a range from this master port and thus the 381 // connected slave module 382 gotAddrRanges[master_port_id] = true; 383 384 // update the global flag 385 if (!gotAllAddrRanges) { 386 // take a logical AND of all the ports and see if we got 387 // ranges from everyone 388 gotAllAddrRanges = true; 389 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 390 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 391 gotAllAddrRanges &= *r++; 392 } 393 if (gotAllAddrRanges) 394 DPRINTF(BusAddrRanges, "Got address ranges from all slaves\n"); 395 } 396 397 // note that we could get the range from the default port at any 398 // point in time, and we cannot assume that the default range is 399 // set before the other ones are, so we do additional checks once 400 // all ranges are provided 401 if (master_port_id == defaultPortID) { 402 // only update if we are indeed checking ranges for the 403 // default port since the port might not have a valid range 404 // otherwise 405 if (useDefaultRange) { 406 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 407 408 if (ranges.size() != 1) 409 fatal("Bus %s may only have a single default range", 410 name()); 411 412 defaultRange = ranges.front(); 413 } 414 } else { 415 // the ports are allowed to update their address ranges 416 // dynamically, so remove any existing entries 417 if (gotAddrRanges[master_port_id]) { 418 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 419 if (p->second == master_port_id) 420 // erasing invalidates the iterator, so advance it 421 // before the deletion takes place 422 portMap.erase(p++); 423 else 424 p++; 425 } 426 } 427 428 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 429 430 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 431 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 432 r->to_string(), master_port_id); 433 if (portMap.insert(*r, master_port_id) == portMap.end()) { 434 PortID conflict_id = portMap.find(*r)->second; 435 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 436 name(), 437 masterPorts[master_port_id]->getSlavePort().name(), 438 masterPorts[conflict_id]->getSlavePort().name()); 439 } 440 } 441 } 442 443 // if we have received ranges from all our neighbouring slave 444 // modules, go ahead and tell our connected master modules in 445 // turn, this effectively assumes a tree structure of the system 446 if (gotAllAddrRanges) { 447 DPRINTF(BusAddrRanges, "Aggregating bus ranges\n"); 448 busRanges.clear(); 449 450 // start out with the default range 451 if (useDefaultRange) { 452 if (!gotAddrRanges[defaultPortID]) 453 fatal("Bus %s uses default range, but none provided", 454 name()); 455 456 busRanges.push_back(defaultRange); 457 DPRINTF(BusAddrRanges, "-- Adding default %s\n", 458 defaultRange.to_string()); 459 } 460 461 // merge all interleaved ranges and add any range that is not 462 // a subset of the default range 463 std::vector<AddrRange> intlv_ranges; 464 for (AddrRangeMap<PortID>::const_iterator r = portMap.begin(); 465 r != portMap.end(); ++r) { 466 // if the range is interleaved then save it for now 467 if (r->first.interleaved()) { 468 // if we already got interleaved ranges that are not 469 // part of the same range, then first do a merge 470 // before we add the new one 471 if (!intlv_ranges.empty() && 472 !intlv_ranges.back().mergesWith(r->first)) { 473 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 474 intlv_ranges.size()); 475 AddrRange merged_range(intlv_ranges); 476 // next decide if we keep the merged range or not 477 if (!(useDefaultRange && 478 merged_range.isSubset(defaultRange))) { 479 busRanges.push_back(merged_range); 480 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 481 merged_range.to_string()); 482 } 483 intlv_ranges.clear(); 484 } 485 intlv_ranges.push_back(r->first); 486 } else { 487 // keep the current range if not a subset of the default 488 if (!(useDefaultRange && 489 r->first.isSubset(defaultRange))) { 490 busRanges.push_back(r->first); 491 DPRINTF(BusAddrRanges, "-- Adding range %s\n", 492 r->first.to_string()); 493 } 494 } 495 } 496 497 // if there is still interleaved ranges waiting to be merged, 498 // go ahead and do it 499 if (!intlv_ranges.empty()) { 500 DPRINTF(BusAddrRanges, "-- Merging range from %d ranges\n", 501 intlv_ranges.size()); 502 AddrRange merged_range(intlv_ranges); 503 if (!(useDefaultRange && merged_range.isSubset(defaultRange))) { 504 busRanges.push_back(merged_range); 505 DPRINTF(BusAddrRanges, "-- Adding merged range %s\n", 506 merged_range.to_string()); 507 } 508 } 509 510 // also check that no range partially overlaps with the 511 // default range, this has to be done after all ranges are set 512 // as there are no guarantees for when the default range is 513 // update with respect to the other ones 514 if (useDefaultRange) { 515 for (AddrRangeConstIter r = busRanges.begin(); 516 r != busRanges.end(); ++r) { 517 // see if the new range is partially 518 // overlapping the default range 519 if (r->intersects(defaultRange) && 520 !r->isSubset(defaultRange)) 521 fatal("Range %s intersects the " \ 522 "default range of %s but is not a " \ 523 "subset\n", r->to_string(), name()); 524 } 525 } 526 527 // tell all our neighbouring master ports that our address 528 // ranges have changed 529 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 530 ++s) 531 (*s)->sendRangeChange(); 532 } 533 534 clearPortCache(); 535} 536 537AddrRangeList 538BaseBus::getAddrRanges() const 539{ 540 // we should never be asked without first having sent a range 541 // change, and the latter is only done once we have all the ranges 542 // of the connected devices 543 assert(gotAllAddrRanges); 544 545 // at the moment, this never happens, as there are no cycles in 546 // the range queries and no devices on the master side of a bus 547 // (CPU, cache, bridge etc) actually care about the ranges of the 548 // ports they are connected to 549 550 DPRINTF(BusAddrRanges, "Received address range request\n"); 551 552 return busRanges; 553} 554 555unsigned 556BaseBus::deviceBlockSize() const 557{ 558 return blockSize; 559} 560 561template <typename PortClass> 562unsigned int 563BaseBus::Layer<PortClass>::drain(DrainManager *dm) 564{ 565 //We should check that we're not "doing" anything, and that noone is 566 //waiting. We might be idle but have someone waiting if the device we 567 //contacted for a retry didn't actually retry. 568 if (state != IDLE) { 569 DPRINTF(Drain, "Bus not drained\n"); 570 drainManager = dm; 571 return 1; 572 } 573 return 0; 574} 575 576/** 577 * Bus layer template instantiations. Could be removed with _impl.hh 578 * file, but since there are only two given options (MasterPort and 579 * SlavePort) it seems a bit excessive at this point. 580 */ 581template class BaseBus::Layer<SlavePort>; 582template class BaseBus::Layer<MasterPort>; 583