xbar.cc revision 9545
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 132Tick 133BaseBus::calcPacketTiming(PacketPtr pkt) 134{ 135 // determine the header time rounded to the closest following 136 // clock edge 137 Tick headerTime = clockEdge(headerCycles); 138 139 // The packet will be sent. Figure out how long it occupies the bus, and 140 // how much of that time is for the first "word", aka bus width. 141 Cycles numCycles(0); 142 if (pkt->hasData()) { 143 // If a packet has data, it needs ceil(size/width) cycles to send it 144 unsigned dataSize = pkt->getSize(); 145 numCycles = Cycles(divCeil(dataSize, width)); 146 } 147 148 // The first word will be delivered on the cycle after the header. 149 pkt->firstWordTime = headerTime + clockPeriod(); 150 151 // Note that currently finishTime can be smaller than 152 // firstWordTime if the packet has no data 153 pkt->finishTime = headerTime + numCycles * clockPeriod(); 154 155 return headerTime; 156} 157 158template <typename PortClass> 159BaseBus::Layer<PortClass>::Layer(BaseBus& _bus, const std::string& _name) : 160 Drainable(), 161 bus(_bus), _name(_name), state(IDLE), drainManager(NULL), 162 releaseEvent(this) 163{ 164} 165 166template <typename PortClass> 167void BaseBus::Layer<PortClass>::occupyLayer(Tick until) 168{ 169 // ensure the state is busy or in retry and never idle at this 170 // point, as the bus should transition from idle as soon as it has 171 // decided to forward the packet to prevent any follow-on calls to 172 // sendTiming seeing an unoccupied bus 173 assert(state != IDLE); 174 175 // note that we do not change the bus state here, if we are going 176 // from idle to busy it is handled by tryTiming, and if we 177 // are in retry we should remain in retry such that 178 // succeededTiming still sees the accurate state 179 180 // until should never be 0 as express snoops never occupy the bus 181 assert(until != 0); 182 bus.schedule(releaseEvent, until); 183 184 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 185 curTick(), until); 186} 187 188template <typename PortClass> 189bool 190BaseBus::Layer<PortClass>::tryTiming(PortClass* port) 191{ 192 // first we see if the bus is busy, next we check if we are in a 193 // retry with a port other than the current one 194 if (state == BUSY || (state == RETRY && port != retryList.front())) { 195 // put the port at the end of the retry list 196 retryList.push_back(port); 197 return false; 198 } 199 200 // update the state which is shared for request, response and 201 // snoop responses, if we were idle we are now busy, if we are in 202 // a retry, then do not change 203 if (state == IDLE) 204 state = BUSY; 205 206 return true; 207} 208 209template <typename PortClass> 210void 211BaseBus::Layer<PortClass>::succeededTiming(Tick busy_time) 212{ 213 // if a retrying port succeeded, also take it off the retry list 214 if (state == RETRY) { 215 DPRINTF(BaseBus, "Remove retry from list %s\n", 216 retryList.front()->name()); 217 retryList.pop_front(); 218 state = BUSY; 219 } 220 221 // we should either have gone from idle to busy in the 222 // tryTiming test, or just gone from a retry to busy 223 assert(state == BUSY); 224 225 // occupy the bus accordingly 226 occupyLayer(busy_time); 227} 228 229template <typename PortClass> 230void 231BaseBus::Layer<PortClass>::failedTiming(PortClass* port, Tick busy_time) 232{ 233 // if we are not in a retry, i.e. busy (but never idle), or we are 234 // in a retry but not for the current port, then add the port at 235 // the end of the retry list 236 if (state != RETRY || port != retryList.front()) { 237 retryList.push_back(port); 238 } 239 240 // even if we retried the current one and did not succeed, 241 // we are no longer retrying but instead busy 242 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 is now idle, so if someone is waiting we can retry 260 if (!retryList.empty()) { 261 // note that we block (return false on recvTiming) both 262 // because the bus is busy and because the destination is 263 // busy, and in the latter case the bus may be released before 264 // we see a retry from the destination 265 retryWaiting(); 266 } else if (drainManager) { 267 DPRINTF(Drain, "Bus done draining, signaling drain manager\n"); 268 //If we weren't able to drain before, do it now. 269 drainManager->signalDrainDone(); 270 // Clear the drain event once we're done with it. 271 drainManager = NULL; 272 } 273} 274 275template <typename PortClass> 276void 277BaseBus::Layer<PortClass>::retryWaiting() 278{ 279 // this should never be called with an empty retry list 280 assert(!retryList.empty()); 281 282 // we always go to retrying from idle 283 assert(state == IDLE); 284 285 // update the state which is shared for request, response and 286 // snoop responses 287 state = RETRY; 288 289 // note that we might have blocked on the receiving port being 290 // busy (rather than the bus itself) and now call retry before the 291 // destination called retry on the bus 292 retryList.front()->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) 296 if (state == RETRY) { 297 retryList.pop_front(); 298 299 //Burn a cycle for the missed grant. 300 301 // update the state which is shared for request, response and 302 // snoop responses 303 state = BUSY; 304 305 // occupy the bus layer until the next cycle ends 306 occupyLayer(bus.clockEdge(Cycles(1))); 307 } 308} 309 310template <typename PortClass> 311void 312BaseBus::Layer<PortClass>::recvRetry() 313{ 314 // we got a retry from a peer that we tried to send something to 315 // and failed, but we sent it on the account of someone else, and 316 // that source port should be on our retry list, however if the 317 // bus layer is released before this happens and the retry (from 318 // the bus point of view) is successful then this no longer holds 319 // and we could in fact have an empty retry list 320 if (retryList.empty()) 321 return; 322 323 // if the bus layer is idle 324 if (state == IDLE) { 325 // note that we do not care who told us to retry at the moment, we 326 // merely let the first one on the retry list go 327 retryWaiting(); 328 } 329} 330 331PortID 332BaseBus::findPort(Addr addr) 333{ 334 // we should never see any address lookups before we've got the 335 // ranges of all connected slave modules 336 assert(gotAllAddrRanges); 337 338 // Check the cache 339 PortID dest_id = checkPortCache(addr); 340 if (dest_id != InvalidPortID) 341 return dest_id; 342 343 // Check the address map interval tree 344 PortMapConstIter i = portMap.find(addr); 345 if (i != portMap.end()) { 346 dest_id = i->second; 347 updatePortCache(dest_id, i->first); 348 return dest_id; 349 } 350 351 // Check if this matches the default range 352 if (useDefaultRange) { 353 if (defaultRange.contains(addr)) { 354 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 355 addr); 356 return defaultPortID; 357 } 358 } else if (defaultPortID != InvalidPortID) { 359 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 360 "will use default port\n", addr); 361 return defaultPortID; 362 } 363 364 // we should use the range for the default port and it did not 365 // match, or the default port is not set 366 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 367 name()); 368} 369 370/** Function called by the port when the bus is receiving a range change.*/ 371void 372BaseBus::recvRangeChange(PortID master_port_id) 373{ 374 DPRINTF(BusAddrRanges, "Received range change from slave port %s\n", 375 masterPorts[master_port_id]->getSlavePort().name()); 376 377 // remember that we got a range from this master port and thus the 378 // connected slave module 379 gotAddrRanges[master_port_id] = true; 380 381 // update the global flag 382 if (!gotAllAddrRanges) { 383 // take a logical AND of all the ports and see if we got 384 // ranges from everyone 385 gotAllAddrRanges = true; 386 std::vector<bool>::const_iterator r = gotAddrRanges.begin(); 387 while (gotAllAddrRanges && r != gotAddrRanges.end()) { 388 gotAllAddrRanges &= *r++; 389 } 390 if (gotAllAddrRanges) 391 DPRINTF(BusAddrRanges, "Got address ranges from all slaves\n"); 392 } 393 394 // note that we could get the range from the default port at any 395 // point in time, and we cannot assume that the default range is 396 // set before the other ones are, so we do additional checks once 397 // all ranges are provided 398 if (master_port_id == defaultPortID) { 399 // only update if we are indeed checking ranges for the 400 // default port since the port might not have a valid range 401 // otherwise 402 if (useDefaultRange) { 403 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 404 405 if (ranges.size() != 1) 406 fatal("Bus %s may only have a single default range", 407 name()); 408 409 defaultRange = ranges.front(); 410 } 411 } else { 412 // the ports are allowed to update their address ranges 413 // dynamically, so remove any existing entries 414 if (gotAddrRanges[master_port_id]) { 415 for (PortMapIter p = portMap.begin(); p != portMap.end(); ) { 416 if (p->second == master_port_id) 417 // erasing invalidates the iterator, so advance it 418 // before the deletion takes place 419 portMap.erase(p++); 420 else 421 p++; 422 } 423 } 424 425 AddrRangeList ranges = masterPorts[master_port_id]->getAddrRanges(); 426 427 for (AddrRangeConstIter r = ranges.begin(); r != ranges.end(); ++r) { 428 DPRINTF(BusAddrRanges, "Adding range %s for id %d\n", 429 r->to_string(), master_port_id); 430 if (portMap.insert(*r, master_port_id) == portMap.end()) { 431 PortID conflict_id = portMap.find(*r)->second; 432 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 433 name(), 434 masterPorts[master_port_id]->getSlavePort().name(), 435 masterPorts[conflict_id]->getSlavePort().name()); 436 } 437 } 438 } 439 440 // if we have received ranges from all our neighbouring slave 441 // modules, go ahead and tell our connected master modules in 442 // turn, this effectively assumes a tree structure of the system 443 if (gotAllAddrRanges) { 444 // also check that no range partially overlaps with the 445 // default range, this has to be done after all ranges are set 446 // as there are no guarantees for when the default range is 447 // update with respect to the other ones 448 if (useDefaultRange) { 449 for (PortID port_id = 0; port_id < masterPorts.size(); ++port_id) { 450 if (port_id == defaultPortID) { 451 if (!gotAddrRanges[port_id]) 452 fatal("Bus %s uses default range, but none provided", 453 name()); 454 } else { 455 AddrRangeList ranges = 456 masterPorts[port_id]->getAddrRanges(); 457 458 for (AddrRangeConstIter r = ranges.begin(); 459 r != ranges.end(); ++r) { 460 // see if the new range is partially 461 // overlapping the default range 462 if (r->intersects(defaultRange) && 463 !r->isSubset(defaultRange)) 464 fatal("Range %s intersects the " \ 465 "default range of %s but is not a " \ 466 "subset\n", r->to_string(), name()); 467 } 468 } 469 } 470 } 471 472 // tell all our neighbouring master ports that our address 473 // ranges have changed 474 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 475 ++s) 476 (*s)->sendRangeChange(); 477 } 478 479 clearPortCache(); 480} 481 482AddrRangeList 483BaseBus::getAddrRanges() const 484{ 485 // we should never be asked without first having sent a range 486 // change, and the latter is only done once we have all the ranges 487 // of the connected devices 488 assert(gotAllAddrRanges); 489 490 // at the moment, this never happens, as there are no cycles in 491 // the range queries and no devices on the master side of a bus 492 // (CPU, cache, bridge etc) actually care about the ranges of the 493 // ports they are connected to 494 495 DPRINTF(BusAddrRanges, "Received address range request, returning:\n"); 496 497 // start out with the default range 498 AddrRangeList ranges; 499 if (useDefaultRange) { 500 ranges.push_back(defaultRange); 501 DPRINTF(BusAddrRanges, " -- Default %s\n", defaultRange.to_string()); 502 } 503 504 // add any range that is not a subset of the default range 505 for (PortMapConstIter p = portMap.begin(); p != portMap.end(); ++p) { 506 if (useDefaultRange && p->first.isSubset(defaultRange)) { 507 DPRINTF(BusAddrRanges, " -- %s is a subset of default\n", 508 p->first.to_string()); 509 } else { 510 ranges.push_back(p->first); 511 DPRINTF(BusAddrRanges, " -- %s\n", p->first.to_string()); 512 } 513 } 514 515 return ranges; 516} 517 518unsigned 519BaseBus::deviceBlockSize() const 520{ 521 return blockSize; 522} 523 524template <typename PortClass> 525unsigned int 526BaseBus::Layer<PortClass>::drain(DrainManager *dm) 527{ 528 //We should check that we're not "doing" anything, and that noone is 529 //waiting. We might be idle but have someone waiting if the device we 530 //contacted for a retry didn't actually retry. 531 if (!retryList.empty() || state != IDLE) { 532 DPRINTF(Drain, "Bus not drained\n"); 533 drainManager = dm; 534 return 1; 535 } 536 return 0; 537} 538 539/** 540 * Bus layer template instantiations. Could be removed with _impl.hh 541 * file, but since there are only two given options (MasterPort and 542 * SlavePort) it seems a bit excessive at this point. 543 */ 544template class BaseBus::Layer<SlavePort>; 545template class BaseBus::Layer<MasterPort>; 546