xbar.cc revision 9549
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 Drainable(), 162 bus(_bus), _name(_name), state(IDLE), drainManager(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 (drainManager) { 268 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 269 //If we weren't able to drain before, do it now. 270 drainManager->signalDrainDone(); 271 // Clear the drain event once we're done with it. 272 drainManager = 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 // occupy the bus layer until the next cycle ends 307 occupyLayer(bus.clockEdge(Cycles(1))); 308 } 309} 310 311template <typename PortClass> 312void 313BaseBus::Layer<PortClass>::recvRetry() 314{ 315 // we got a retry from a peer that we tried to send something to 316 // and failed, but we sent it on the account of someone else, and 317 // that source port should be on our retry list, however if the 318 // bus layer is released before this happens and the retry (from 319 // the bus point of view) is successful then this no longer holds 320 // and we could in fact have an empty retry list 321 if (retryList.empty()) 322 return; 323 324 // if the bus layer is idle 325 if (state == IDLE) { 326 // note that we do not care who told us to retry at the moment, we 327 // merely let the first one on the retry list go 328 retryWaiting(); 329 } 330} 331 332PortID 333BaseBus::findPort(Addr addr) 334{ 335 // we should never see any address lookups before we've got the 336 // ranges of all connected slave modules 337 assert(gotAllAddrRanges); 338 339 // Check the cache 340 PortID dest_id = checkPortCache(addr); 341 if (dest_id != InvalidPortID) 342 return dest_id; 343 344 // Check the address map interval tree 345 PortMapConstIter i = portMap.find(addr); 346 if (i != portMap.end()) { 347 dest_id = i->second; 348 updatePortCache(dest_id, i->first); 349 return dest_id; 350 } 351 352 // Check if this matches the default range 353 if (useDefaultRange) { 354 if (defaultRange.contains(addr)) { 355 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 356 addr); 357 return defaultPortID; 358 } 359 } else if (defaultPortID != InvalidPortID) { 360 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 361 "will use default port\n", addr); 362 return defaultPortID; 363 } 364 365 // we should use the range for the default port and it did not 366 // match, or the default port is not set 367 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 368 name()); 369} 370 371/** Function called by the port when the bus is receiving a range change.*/ 372void 373BaseBus::recvRangeChange(PortID master_port_id) 374{ 375 DPRINTF(BusAddrRanges, "Received range change from slave port %s\n", 376 masterPorts[master_port_id]->getSlavePort().name()); 377 378 // remember that we got a range from this master port and thus the 379 // connected slave module 380 gotAddrRanges[master_port_id] = true; 381 382 // update the global flag 383 if (!gotAllAddrRanges) { 384 // take a logical AND of all the ports and see if we got 385 // ranges from everyone 386 gotAllAddrRanges = true; 387 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 388 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 389 gotAllAddrRanges &= *r++; 390 } 391 if (gotAllAddrRanges) 392 DPRINTF(BusAddrRanges, "Got address ranges from all slaves\n"); 393 } 394 395 // note that we could get the range from the default port at any 396 // point in time, and we cannot assume that the default range is 397 // set before the other ones are, so we do additional checks once 398 // all ranges are provided 399 if (master_port_id == defaultPortID) { 400 // only update if we are indeed checking ranges for the 401 // default port since the port might not have a valid range 402 // otherwise 403 if (useDefaultRange) { 404 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 405 406 if (ranges.size() != 1) 407 fatal("Bus %s may only have a single default range", 408 name()); 409 410 defaultRange = ranges.front(); 411 } 412 } else { 413 // the ports are allowed to update their address ranges 414 // dynamically, so remove any existing entries 415 if (gotAddrRanges[master_port_id]) { 416 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 417 if (p->second == master_port_id) 418 // erasing invalidates the iterator, so advance it 419 // before the deletion takes place 420 portMap.erase(p++); 421 else 422 p++; 423 } 424 } 425 426 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 427 428 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 429 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 430 r->to_string(), master_port_id); 431 if (portMap.insert(*r, master_port_id) == portMap.end()) { 432 PortID conflict_id = portMap.find(*r)->second; 433 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 434 name(), 435 masterPorts[master_port_id]->getSlavePort().name(), 436 masterPorts[conflict_id]->getSlavePort().name()); 437 } 438 } 439 } 440 441 // if we have received ranges from all our neighbouring slave 442 // modules, go ahead and tell our connected master modules in 443 // turn, this effectively assumes a tree structure of the system 444 if (gotAllAddrRanges) { 445 // also check that no range partially overlaps with the 446 // default range, this has to be done after all ranges are set 447 // as there are no guarantees for when the default range is 448 // update with respect to the other ones 449 if (useDefaultRange) { 450 for (PortID port_id = 0; port_id < masterPorts.size(); ++port_id) { 451 if (port_id == defaultPortID) { 452 if (!gotAddrRanges[port_id]) 453 fatal("Bus %s uses default range, but none provided", 454 name()); 455 } else { 456 AddrRangeList ranges = 457 masterPorts[port_id]->getAddrRanges(); 458 459 for (AddrRangeConstIter r = ranges.begin(); 460 r != ranges.end(); ++r) { 461 // see if the new range is partially 462 // overlapping the default range 463 if (r->intersects(defaultRange) && 464 !r->isSubset(defaultRange)) 465 fatal("Range %s intersects the " \ 466 "default range of %s but is not a " \ 467 "subset\n", r->to_string(), name()); 468 } 469 } 470 } 471 } 472 473 // tell all our neighbouring master ports that our address 474 // ranges have changed 475 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 476 ++s) 477 (*s)->sendRangeChange(); 478 } 479 480 clearPortCache(); 481} 482 483AddrRangeList 484BaseBus::getAddrRanges() const 485{ 486 // we should never be asked without first having sent a range 487 // change, and the latter is only done once we have all the ranges 488 // of the connected devices 489 assert(gotAllAddrRanges); 490 491 // at the moment, this never happens, as there are no cycles in 492 // the range queries and no devices on the master side of a bus 493 // (CPU, cache, bridge etc) actually care about the ranges of the 494 // ports they are connected to 495 496 DPRINTF(BusAddrRanges, "Received address range request, returning:\n"); 497 498 // start out with the default range 499 AddrRangeList ranges; 500 if (useDefaultRange) { 501 ranges.push_back(defaultRange); 502 DPRINTF(BusAddrRanges, " -- Default %s\n", defaultRange.to_string()); 503 } 504 505 // add any range that is not a subset of the default range 506 for (PortMapConstIter p = portMap.begin(); p != portMap.end(); ++p) { 507 if (useDefaultRange && p->first.isSubset(defaultRange)) { 508 DPRINTF(BusAddrRanges, " -- %s is a subset of default\n", 509 p->first.to_string()); 510 } else { 511 ranges.push_back(p->first); 512 DPRINTF(BusAddrRanges, " -- %s\n", p->first.to_string()); 513 } 514 } 515 516 return ranges; 517} 518 519unsigned 520BaseBus::deviceBlockSize() const 521{ 522 return blockSize; 523} 524 525template <typename PortClass> 526unsigned int 527BaseBus::Layer<PortClass>::drain(DrainManager *dm) 528{ 529 //We should check that we're not "doing" anything, and that noone is 530 //waiting. We might be idle but have someone waiting if the device we 531 //contacted for a retry didn't actually retry. 532 if (!retryList.empty() || state != IDLE) { 533 DPRINTF(Drain, "Bus not drained\n"); 534 drainManager = dm; 535 return 1; 536 } 537 return 0; 538} 539 540/** 541 * Bus layer template instantiations. Could be removed with _impl.hh 542 * file, but since there are only two given options (MasterPort and 543 * SlavePort) it seems a bit excessive at this point. 544 */ 545template class BaseBus::Layer<SlavePort>; 546template class BaseBus::Layer<MasterPort>; 547