xbar.cc revision 9091
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 "mem/bus.hh" 56 57BaseBus::BaseBus(const BaseBusParams *p) 58 : MemObject(p), state(IDLE), clock(p->clock), 59 headerCycles(p->header_cycles), width(p->width), 60 drainEvent(NULL), busIdleEvent(this), 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 141void BaseBus::occupyBus(Tick until) 142{ 143 // ensure the state is busy or in retry and never idle at this 144 // point, as the bus should transition from idle as soon as it has 145 // decided to forward the packet to prevent any follow-on calls to 146 // sendTiming seeing an unoccupied bus 147 assert(state != IDLE); 148 149 // note that we do not change the bus state here, if we are going 150 // from idle to busy it is handled by tryTiming, and if we 151 // are in retry we should remain in retry such that 152 // succeededTiming still sees the accurate state 153 154 // until should never be 0 as express snoops never occupy the bus 155 assert(until != 0); 156 schedule(busIdleEvent, until); 157 158 DPRINTF(BaseBus, "The bus is now busy from tick %d to %d\n", 159 curTick(), until); 160} 161 162bool 163BaseBus::tryTiming(Port* port) 164{ 165 // first we see if the bus is busy, next we check if we are in a 166 // retry with a port other than the current one 167 if (state == BUSY || (state == RETRY && port != retryList.front())) { 168 // put the port at the end of the retry list 169 retryList.push_back(port); 170 return false; 171 } 172 173 // update the state which is shared for request, response and 174 // snoop responses, if we were idle we are now busy, if we are in 175 // a retry, then do not change 176 if (state == IDLE) 177 state = BUSY; 178 179 return true; 180} 181 182void 183BaseBus::succeededTiming(Tick busy_time) 184{ 185 // if a retrying port succeeded, also take it off the retry list 186 if (state == RETRY) { 187 DPRINTF(BaseBus, "Remove retry from list %s\n", 188 retryList.front()->name()); 189 retryList.pop_front(); 190 state = BUSY; 191 } 192 193 // we should either have gone from idle to busy in the 194 // tryTiming test, or just gone from a retry to busy 195 assert(state == BUSY); 196 197 // occupy the bus accordingly 198 occupyBus(busy_time); 199} 200 201void 202BaseBus::failedTiming(SlavePort* port, Tick busy_time) 203{ 204 // if we are not in a retry, i.e. busy (but never idle), or we are 205 // in a retry but not for the current port, then add the port at 206 // the end of the retry list 207 if (state != RETRY || port != retryList.front()) { 208 retryList.push_back(port); 209 } 210 211 // even if we retried the current one and did not succeed, 212 // we are no longer retrying but instead busy 213 state = BUSY; 214 215 // occupy the bus accordingly 216 occupyBus(busy_time); 217} 218 219void 220BaseBus::releaseBus() 221{ 222 // releasing the bus means we should now be idle 223 assert(state == BUSY); 224 assert(!busIdleEvent.scheduled()); 225 226 // update the state 227 state = IDLE; 228 229 // bus is now idle, so if someone is waiting we can retry 230 if (!retryList.empty()) { 231 // note that we block (return false on recvTiming) both 232 // because the bus is busy and because the destination is 233 // busy, and in the latter case the bus may be released before 234 // we see a retry from the destination 235 retryWaiting(); 236 } else if (drainEvent) { 237 //If we weren't able to drain before, do it now. 238 drainEvent->process(); 239 // Clear the drain event once we're done with it. 240 drainEvent = NULL; 241 } 242} 243 244void 245BaseBus::retryWaiting() 246{ 247 // this should never be called with an empty retry list 248 assert(!retryList.empty()); 249 250 // we always go to retrying from idle 251 assert(state == IDLE); 252 253 // update the state which is shared for request, response and 254 // snoop responses 255 state = RETRY; 256 257 // note that we might have blocked on the receiving port being 258 // busy (rather than the bus itself) and now call retry before the 259 // destination called retry on the bus 260 if (dynamic_cast<SlavePort*>(retryList.front()) != NULL) 261 (dynamic_cast<SlavePort*>(retryList.front()))->sendRetry(); 262 else 263 (dynamic_cast<MasterPort*>(retryList.front()))->sendRetry(); 264 265 // If the bus is still in the retry state, sendTiming wasn't 266 // called in zero time (e.g. the cache does this) 267 if (state == RETRY) { 268 retryList.pop_front(); 269 270 //Burn a cycle for the missed grant. 271 272 // update the state which is shared for request, response and 273 // snoop responses 274 state = BUSY; 275 276 // determine the current time rounded to the closest following 277 // clock edge 278 Tick now = divCeil(curTick(), clock) * clock; 279 280 occupyBus(now + clock); 281 } 282} 283 284void 285BaseBus::recvRetry() 286{ 287 // we got a retry from a peer that we tried to send something to 288 // and failed, but we sent it on the account of someone else, and 289 // that source port should be on our retry list, however if the 290 // bus is released before this happens and the retry (from the bus 291 // point of view) is successful then this no longer holds and we 292 // could in fact have an empty retry list 293 if (retryList.empty()) 294 return; 295 296 // if the bus is idle 297 if (state == IDLE) { 298 // note that we do not care who told us to retry at the moment, we 299 // merely let the first one on the retry list go 300 retryWaiting(); 301 } 302} 303 304PortID 305BaseBus::findPort(Addr addr) 306{ 307 /* An interval tree would be a better way to do this. --ali. */ 308 PortID dest_id = checkPortCache(addr); 309 if (dest_id != InvalidPortID) 310 return dest_id; 311 312 // Check normal port ranges 313 PortMapConstIter i = portMap.find(RangeSize(addr,1)); 314 if (i != portMap.end()) { 315 dest_id = i->second; 316 updatePortCache(dest_id, i->first.start, i->first.end); 317 return dest_id; 318 } 319 320 // Check if this matches the default range 321 if (useDefaultRange) { 322 AddrRangeConstIter a_end = defaultRange.end(); 323 for (AddrRangeConstIter i = defaultRange.begin(); i != a_end; i++) { 324 if (*i == addr) { 325 DPRINTF(BusAddrRanges, " found addr %#llx on default\n", 326 addr); 327 return defaultPortID; 328 } 329 } 330 } else if (defaultPortID != InvalidPortID) { 331 DPRINTF(BusAddrRanges, "Unable to find destination for addr %#llx, " 332 "will use default port\n", addr); 333 return defaultPortID; 334 } 335 336 // we should use the range for the default port and it did not 337 // match, or the default port is not set 338 fatal("Unable to find destination for addr %#llx on bus %s\n", addr, 339 name()); 340} 341 342/** Function called by the port when the bus is receiving a range change.*/ 343void 344BaseBus::recvRangeChange(PortID master_port_id) 345{ 346 AddrRangeList ranges; 347 AddrRangeIter iter; 348 349 if (inRecvRangeChange.count(master_port_id)) 350 return; 351 inRecvRangeChange.insert(master_port_id); 352 353 DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", 354 master_port_id); 355 356 clearPortCache(); 357 if (master_port_id == defaultPortID) { 358 defaultRange.clear(); 359 // Only try to update these ranges if the user set a default responder. 360 if (useDefaultRange) { 361 // get the address ranges of the connected slave port 362 AddrRangeList ranges = 363 masterPorts[master_port_id]->getAddrRanges(); 364 for(iter = ranges.begin(); iter != ranges.end(); iter++) { 365 defaultRange.push_back(*iter); 366 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n", 367 iter->start, iter->end); 368 } 369 } 370 } else { 371 372 assert(master_port_id < masterPorts.size() && master_port_id >= 0); 373 MasterPort *port = masterPorts[master_port_id]; 374 375 // Clean out any previously existent ids 376 for (PortMapIter portIter = portMap.begin(); 377 portIter != portMap.end(); ) { 378 if (portIter->second == master_port_id) 379 portMap.erase(portIter++); 380 else 381 portIter++; 382 } 383 384 // get the address ranges of the connected slave port 385 ranges = port->getAddrRanges(); 386 387 for (iter = ranges.begin(); iter != ranges.end(); iter++) { 388 DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n", 389 iter->start, iter->end, master_port_id); 390 if (portMap.insert(*iter, master_port_id) == portMap.end()) { 391 PortID conflict_id = portMap.find(*iter)->second; 392 fatal("%s has two ports with same range:\n\t%s\n\t%s\n", 393 name(), 394 masterPorts[master_port_id]->getSlavePort().name(), 395 masterPorts[conflict_id]->getSlavePort().name()); 396 } 397 } 398 } 399 DPRINTF(BusAddrRanges, "port list has %d entries\n", portMap.size()); 400 401 // tell all our neighbouring master ports that our address range 402 // has changed 403 for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end(); 404 ++p) 405 (*p)->sendRangeChange(); 406 407 inRecvRangeChange.erase(master_port_id); 408} 409 410AddrRangeList 411BaseBus::getAddrRanges() const 412{ 413 AddrRangeList ranges; 414 415 DPRINTF(BusAddrRanges, "received address range request, returning:\n"); 416 417 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 418 dflt_iter != defaultRange.end(); dflt_iter++) { 419 ranges.push_back(*dflt_iter); 420 DPRINTF(BusAddrRanges, " -- Dflt: %#llx : %#llx\n",dflt_iter->start, 421 dflt_iter->end); 422 } 423 for (PortMapConstIter portIter = portMap.begin(); 424 portIter != portMap.end(); portIter++) { 425 bool subset = false; 426 for (AddrRangeConstIter dflt_iter = defaultRange.begin(); 427 dflt_iter != defaultRange.end(); dflt_iter++) { 428 if ((portIter->first.start < dflt_iter->start && 429 portIter->first.end >= dflt_iter->start) || 430 (portIter->first.start < dflt_iter->end && 431 portIter->first.end >= dflt_iter->end)) 432 fatal("Devices can not set ranges that itersect the default set\ 433 but are not a subset of the default set.\n"); 434 if (portIter->first.start >= dflt_iter->start && 435 portIter->first.end <= dflt_iter->end) { 436 subset = true; 437 DPRINTF(BusAddrRanges, " -- %#llx : %#llx is a SUBSET\n", 438 portIter->first.start, portIter->first.end); 439 } 440 } 441 if (!subset) { 442 ranges.push_back(portIter->first); 443 DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n", 444 portIter->first.start, portIter->first.end); 445 } 446 } 447 448 return ranges; 449} 450 451unsigned 452BaseBus::findBlockSize() 453{ 454 if (cachedBlockSizeValid) 455 return cachedBlockSize; 456 457 unsigned max_bs = 0; 458 459 for (MasterPortConstIter m = masterPorts.begin(); m != masterPorts.end(); 460 ++m) { 461 unsigned tmp_bs = (*m)->peerBlockSize(); 462 if (tmp_bs > max_bs) 463 max_bs = tmp_bs; 464 } 465 466 for (SlavePortConstIter s = slavePorts.begin(); s != slavePorts.end(); 467 ++s) { 468 unsigned tmp_bs = (*s)->peerBlockSize(); 469 if (tmp_bs > max_bs) 470 max_bs = tmp_bs; 471 } 472 if (max_bs == 0) 473 max_bs = defaultBlockSize; 474 475 if (max_bs != 64) 476 warn_once("Blocksize found to not be 64... hmm... probably not.\n"); 477 cachedBlockSize = max_bs; 478 cachedBlockSizeValid = true; 479 return max_bs; 480} 481 482 483unsigned int 484BaseBus::drain(Event * de) 485{ 486 //We should check that we're not "doing" anything, and that noone is 487 //waiting. We might be idle but have someone waiting if the device we 488 //contacted for a retry didn't actually retry. 489 if (!retryList.empty() || state != IDLE) { 490 drainEvent = de; 491 return 1; 492 } 493 return 0; 494} 495