xbar.cc revision 9152
1/* 2 * Copyright (c) 2011-2012 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/intmath.hh" 51#include "base/misc.hh" 52#include "base/trace.hh" 53#include "debug/Bus.hh" 54#include "debug/BusAddrRanges.hh" 55#include "debug/Drain.hh" 56#include "mem/bus.hh" 57 58BaseBus::BaseBus(const BaseBusParams *p) 59 : MemObject(p), clock(p->clock), 60 headerCycles(p->header_cycles), width(p->width), 61 defaultPortID(InvalidPortID), 62 useDefaultRange(p->use_default_range), 63 defaultBlockSize(p->block_size), 64 cachedBlockSize(0), cachedBlockSizeValid(false) 65{ 66 //width, clock period, and header cycles must be positive 67 if (width <= 0) 68 fatal("Bus width must be positive\n"); 69 if (clock <= 0) 70 fatal("Bus clock period must be positive\n"); 71 if (headerCycles <= 0) 72 fatal("Number of header cycles must be positive\n"); 73} 74 75BaseBus::~BaseBus() 76{ 77 for (MasterPortIter m = masterPorts.begin(); m != masterPorts.end(); 78 ++m) { 79 delete *m; 80 } 81 82 for (SlavePortIter s = slavePorts.begin(); s != slavePorts.end(); 83 ++s) { 84 delete *s; 85 } 86} 87 88MasterPort & 89BaseBus::getMasterPort(const std::string &if_name, int idx) 90{ 91 if (if_name == "master" && idx < masterPorts.size()) { 92 // the master port index translates directly to the vector position 93 return *masterPorts[idx]; 94 } else if (if_name == "default") { 95 return *masterPorts[defaultPortID]; 96 } else { 97 return MemObject::getMasterPort(if_name, idx); 98 } 99} 100 101SlavePort & 102BaseBus::getSlavePort(const std::string &if_name, int idx) 103{ 104 if (if_name == "slave" && idx < slavePorts.size()) { 105 // the slave port index translates directly to the vector position 106 return *slavePorts[idx]; 107 } else { 108 return MemObject::getSlavePort(if_name, idx); 109 } 110} 111 112Tick 113BaseBus::calcPacketTiming(PacketPtr pkt) 114{ 115 // determine the current time rounded to the closest following 116 // clock edge 117 Tick now = divCeil(curTick(), clock) * clock; 118 119 Tick headerTime = now + headerCycles * clock; 120 121 // The packet will be sent. Figure out how long it occupies the bus, and 122 // how much of that time is for the first "word", aka bus width. 123 int numCycles = 0; 124 if (pkt->hasData()) { 125 // If a packet has data, it needs ceil(size/width) cycles to send it 126 int dataSize = pkt->getSize(); 127 numCycles += dataSize/width; 128 if (dataSize % width) 129 numCycles++; 130 } 131 132 // The first word will be delivered after the current tick, the delivery 133 // of the address if any, and one bus cycle to deliver the data 134 pkt->firstWordTime = headerTime + clock; 135 136 pkt->finishTime = headerTime + numCycles * clock; 137 138 return headerTime; 139} 140 141template <typename PortClass> 142BaseBus::Layer<PortClass>::Layer(BaseBus& _bus, const std::string& _name, 143 Tick _clock) : 144 bus(_bus), _name(_name), state(IDLE), clock(_clock), drainEvent(NULL), 145 releaseEvent(this) 146{ 147} 148 149template <typename PortClass> 150void BaseBus::Layer<PortClass>::occupyLayer(Tick until) 151{ 152 // ensure the state is busy or in retry and never idle at this 153 // point, as the bus should transition from idle as soon as it has 154 // decided to forward the packet to prevent any follow-on calls to 155 // sendTiming seeing an unoccupied bus 156 assert(state != IDLE); 157 158 // note that we do not change the bus state here, if we are going 159 // from idle to busy it is handled by tryTiming, and if we 160 // are in retry we should remain in retry such that 161 // succeededTiming still sees the accurate state 162 163 // until should never be 0 as express snoops never occupy the bus 164 assert(until != 0); 165 bus.schedule(releaseEvent, until); 166 167 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 168 curTick(), until); 169} 170 171template <typename PortClass> 172bool 173BaseBus::Layer<PortClass>::tryTiming(PortClass* port) 174{ 175 // first we see if the bus is busy, next we check if we are in a 176 // retry with a port other than the current one 177 if (state == BUSY || (state == RETRY && port != retryList.front())) { 178 // put the port at the end of the retry list 179 retryList.push_back(port); 180 return false; 181 } 182 183 // update the state which is shared for request, response and 184 // snoop responses, if we were idle we are now busy, if we are in 185 // a retry, then do not change 186 if (state == IDLE) 187 state = BUSY; 188 189 return true; 190} 191 192template <typename PortClass> 193void 194BaseBus::Layer<PortClass>::succeededTiming(Tick busy_time) 195{ 196 // if a retrying port succeeded, also take it off the retry list 197 if (state == RETRY) { 198 DPRINTF(BaseBus, "Remove retry from list %s\n", 199 retryList.front()->name()); 200 retryList.pop_front(); 201 state = BUSY; 202 } 203 204 // we should either have gone from idle to busy in the 205 // tryTiming test, or just gone from a retry to busy 206 assert(state == BUSY); 207 208 // occupy the bus accordingly 209 occupyLayer(busy_time); 210} 211 212template <typename PortClass> 213void 214BaseBus::Layer<PortClass>::failedTiming(PortClass* port, Tick busy_time) 215{ 216 // if we are not in a retry, i.e. busy (but never idle), or we are 217 // in a retry but not for the current port, then add the port at 218 // the end of the retry list 219 if (state != RETRY || port != retryList.front()) { 220 retryList.push_back(port); 221 } 222 223 // even if we retried the current one and did not succeed, 224 // we are no longer retrying but instead busy 225 state = BUSY; 226 227 // occupy the bus accordingly 228 occupyLayer(busy_time); 229} 230 231template <typename PortClass> 232void 233BaseBus::Layer<PortClass>::releaseLayer() 234{ 235 // releasing the bus means we should now be idle 236 assert(state == BUSY); 237 assert(!releaseEvent.scheduled()); 238 239 // update the state 240 state = IDLE; 241 242 // bus is now idle, so if someone is waiting we can retry 243 if (!retryList.empty()) { 244 // note that we block (return false on recvTiming) both 245 // because the bus is busy and because the destination is 246 // busy, and in the latter case the bus may be released before 247 // we see a retry from the destination 248 retryWaiting(); 249 } else if (drainEvent) { 250 DPRINTF(Drain, "Bus done draining, processing drain event\n"); 251 //If we weren't able to drain before, do it now. 252 drainEvent->process(); 253 // Clear the drain event once we're done with it. 254 drainEvent = NULL; 255 } 256} 257 258template <typename PortClass> 259void 260BaseBus::Layer<PortClass>::retryWaiting() 261{ 262 // this should never be called with an empty retry list 263 assert(!retryList.empty()); 264 265 // we always go to retrying from idle 266 assert(state == IDLE); 267 268 // update the state which is shared for request, response and 269 // snoop responses 270 state = RETRY; 271 272 // note that we might have blocked on the receiving port being 273 // busy (rather than the bus itself) and now call retry before the 274 // destination called retry on the bus 275 retryList.front()->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) 279 if (state == RETRY) { 280 retryList.pop_front(); 281 282 //Burn a cycle for the missed grant. 283 284 // update the state which is shared for request, response and 285 // snoop responses 286 state = BUSY; 287 288 // determine the current time rounded to the closest following 289 // clock edge 290 Tick now = divCeil(curTick(), clock) * clock; 291 292 occupyLayer(now + clock); 293 } 294} 295 296template <typename PortClass> 297void 298BaseBus::Layer<PortClass>::recvRetry() 299{ 300 // we got a retry from a peer that we tried to send something to 301 // and failed, but we sent it on the account of someone else, and 302 // that source port should be on our retry list, however if the 303 // bus layer is released before this happens and the retry (from 304 // the bus point of view) is successful then this no longer holds 305 // and we could in fact have an empty retry list 306 if (retryList.empty()) 307 return; 308 309 // if the bus layer is idle 310 if (state == IDLE) { 311 // note that we do not care who told us to retry at the moment, we 312 // merely let the first one on the retry list go 313 retryWaiting(); 314 } 315} 316 317PortID 318BaseBus::findPort(Addr addr) 319{ 320 /* An interval tree would be a better way to do this. --ali. */ 321 PortID dest_id = checkPortCache(addr); 322 if (dest_id != InvalidPortID) 323 return dest_id; 324 325 // Check normal port ranges 326 PortMapConstIter i = portMap.find(RangeSize(addr,1)); 327 if (i != portMap.end()) { 328 dest_id = i->second; 329 updatePortCache(dest_id, i->first.start, i->first.end); 330 return dest_id; 331 } 332 333 // Check if this matches the default range 334 if (useDefaultRange) { 335 AddrRangeConstIter a_end = defaultRange.end(); 336 for (AddrRangeConstIter i = defaultRange.begin(); i != a_end; i++) { 337 if (*i == addr) { 338 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 339 addr); 340 return defaultPortID; 341 } 342 } 343 } else if (defaultPortID != InvalidPortID) { 344 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 345 "will use default port\n", addr); 346 return defaultPortID; 347 } 348 349 // we should use the range for the default port and it did not 350 // match, or the default port is not set 351 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 352 name()); 353} 354 355/** Function called by the port when the bus is receiving a range change.*/ 356void 357BaseBus::recvRangeChange(PortID master_port_id) 358{ 359 AddrRangeList ranges; 360 AddrRangeIter iter; 361 362 if (inRecvRangeChange.count(master_port_id)) 363 return; 364 inRecvRangeChange.insert(master_port_id); 365 366 DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", 367 master_port_id); 368 369 clearPortCache(); 370 if (master_port_id == defaultPortID) { 371 defaultRange.clear(); 372 // Only try to update these ranges if the user set a default responder. 373 if (useDefaultRange) { 374 // get the address ranges of the connected slave port 375 AddrRangeList ranges = 376 masterPorts[master_port_id]->getAddrRanges(); 377 for(iter = ranges.begin(); iter != ranges.end(); iter++) { 378 defaultRange.push_back(*iter); 379 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n", 380 iter->start, iter->end); 381 } 382 } 383 } else { 384 385 assert(master_port_id < masterPorts.size() && master_port_id >= 0); 386 MasterPort *port = masterPorts[master_port_id]; 387 388 // Clean out any previously existent ids 389 for (PortMapIter portIter = portMap.begin(); 390 portIter != portMap.end(); ) { 391 if (portIter->second == master_port_id) 392 portMap.erase(portIter++); 393 else 394 portIter++; 395 } 396 397 // get the address ranges of the connected slave port 398 ranges = port->getAddrRanges(); 399 400 for (iter = ranges.begin(); iter != ranges.end(); iter++) { 401 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n", 402 iter->start, iter->end, master_port_id); 403 if (portMap.insert(*iter, master_port_id) == portMap.end()) { 404 PortID conflict_id = portMap.find(*iter)->second; 405 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 406 name(), 407 masterPorts[master_port_id]->getSlavePort().name(), 408 masterPorts[conflict_id]->getSlavePort().name()); 409 } 410 } 411 } 412 DPRINTF(BusAddrRanges, "port list has %d entries\n", portMap.size()); 413 414 // tell all our neighbouring master ports that our address range 415 // has changed 416 for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end(); 417 ++p) 418 (*p)->sendRangeChange(); 419 420 inRecvRangeChange.erase(master_port_id); 421} 422 423AddrRangeList 424BaseBus::getAddrRanges() const 425{ 426 AddrRangeList ranges; 427 428 DPRINTF(BusAddrRanges, "received address range request, returning:\n"); 429 430 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 431 dflt_iter != defaultRange.end(); dflt_iter++) { 432 ranges.push_back(*dflt_iter); 433 DPRINTF(BusAddrRanges, " -- Dflt: %#llx : %#llx\n",dflt_iter->start, 434 dflt_iter->end); 435 } 436 for (PortMapConstIter portIter = portMap.begin(); 437 portIter != portMap.end(); portIter++) { 438 bool subset = false; 439 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 440 dflt_iter != defaultRange.end(); dflt_iter++) { 441 if ((portIter->first.start < dflt_iter->start && 442 portIter->first.end >= dflt_iter->start) || 443 (portIter->first.start < dflt_iter->end && 444 portIter->first.end >= dflt_iter->end)) 445 fatal("Devices can not set ranges that itersect the default set\ 446 but are not a subset of the default set.\n"); 447 if (portIter->first.start >= dflt_iter->start && 448 portIter->first.end <= dflt_iter->end) { 449 subset = true; 450 DPRINTF(BusAddrRanges, " -- %#llx : %#llx is a SUBSET\n", 451 portIter->first.start, portIter->first.end); 452 } 453 } 454 if (!subset) { 455 ranges.push_back(portIter->first); 456 DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n", 457 portIter->first.start, portIter->first.end); 458 } 459 } 460 461 return ranges; 462} 463 464unsigned 465BaseBus::findBlockSize() 466{ 467 if (cachedBlockSizeValid) 468 return cachedBlockSize; 469 470 unsigned max_bs = 0; 471 472 for (MasterPortConstIter m = masterPorts.begin(); m != masterPorts.end(); 473 ++m) { 474 unsigned tmp_bs = (*m)->peerBlockSize(); 475 if (tmp_bs > max_bs) 476 max_bs = tmp_bs; 477 } 478 479 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 480 ++s) { 481 unsigned tmp_bs = (*s)->peerBlockSize(); 482 if (tmp_bs > max_bs) 483 max_bs = tmp_bs; 484 } 485 if (max_bs == 0) 486 max_bs = defaultBlockSize; 487 488 if (max_bs != 64) 489 warn_once("Blocksize found to not be 64... hmm... probably not.\n"); 490 cachedBlockSize = max_bs; 491 cachedBlockSizeValid = true; 492 return max_bs; 493} 494 495template <typename PortClass> 496unsigned int 497BaseBus::Layer<PortClass>::drain(Event * de) 498{ 499 //We should check that we're not "doing" anything, and that noone is 500 //waiting. We might be idle but have someone waiting if the device we 501 //contacted for a retry didn't actually retry. 502 if (!retryList.empty() || state != IDLE) { 503 DPRINTF(Drain, "Bus not drained\n"); 504 drainEvent = de; 505 return 1; 506 } 507 return 0; 508} 509 510/** 511 * Bus layer template instantiations. Could be removed with _impl.hh 512 * file, but since there are only two given options (MasterPort and 513 * SlavePort) it seems a bit excessive at this point. 514 */ 515template class BaseBus::Layer<SlavePort>; 516template class BaseBus::Layer<MasterPort>; 517