bridge.cc (9095:0e6bd7082fac) | bridge.cc (9164:d112473185ea) |
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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 --- 35 unchanged lines hidden (view full) --- 44 45/** 46 * @file 47 * Implementation of a memory-mapped bus bridge that connects a master 48 * and a slave through a request and response queue. 49 */ 50 51#include "base/trace.hh" | 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 --- 35 unchanged lines hidden (view full) --- 44 45/** 46 * @file 47 * Implementation of a memory-mapped bus bridge that connects a master 48 * and a slave through a request and response queue. 49 */ 50 51#include "base/trace.hh" |
52#include "debug/BusBridge.hh" | 52#include "debug/Bridge.hh" |
53#include "mem/bridge.hh" 54#include "params/Bridge.hh" 55 | 53#include "mem/bridge.hh" 54#include "params/Bridge.hh" 55 |
56Bridge::BridgeSlavePort::BridgeSlavePort(const std::string &_name, 57 Bridge* _bridge, | 56Bridge::BridgeSlavePort::BridgeSlavePort(const std::string& _name, 57 Bridge& _bridge, |
58 BridgeMasterPort& _masterPort, | 58 BridgeMasterPort& _masterPort, |
59 int _delay, int _nack_delay, 60 int _resp_limit, | 59 int _delay, int _resp_limit, |
61 std::vector<Range<Addr> > _ranges) | 60 std::vector<Range<Addr> > _ranges) |
62 : SlavePort(_name, _bridge), bridge(_bridge), masterPort(_masterPort), 63 delay(_delay), nackDelay(_nack_delay), 64 ranges(_ranges.begin(), _ranges.end()), 65 outstandingResponses(0), inRetry(false), | 61 : SlavePort(_name, &_bridge), bridge(_bridge), masterPort(_masterPort), 62 delay(_delay), ranges(_ranges.begin(), _ranges.end()), 63 outstandingResponses(0), retryReq(false), |
66 respQueueLimit(_resp_limit), sendEvent(*this) 67{ 68} 69 | 64 respQueueLimit(_resp_limit), sendEvent(*this) 65{ 66} 67 |
70Bridge::BridgeMasterPort::BridgeMasterPort(const std::string &_name, 71 Bridge* _bridge, | 68Bridge::BridgeMasterPort::BridgeMasterPort(const std::string& _name, 69 Bridge& _bridge, |
72 BridgeSlavePort& _slavePort, 73 int _delay, int _req_limit) | 70 BridgeSlavePort& _slavePort, 71 int _delay, int _req_limit) |
74 : MasterPort(_name, _bridge), bridge(_bridge), slavePort(_slavePort), 75 delay(_delay), inRetry(false), reqQueueLimit(_req_limit), 76 sendEvent(*this) | 72 : MasterPort(_name, &_bridge), bridge(_bridge), slavePort(_slavePort), 73 delay(_delay), reqQueueLimit(_req_limit), sendEvent(*this) |
77{ 78} 79 80Bridge::Bridge(Params *p) 81 : MemObject(p), | 74{ 75} 76 77Bridge::Bridge(Params *p) 78 : MemObject(p), |
82 slavePort(p->name + ".slave", this, masterPort, p->delay, 83 p->nack_delay, p->resp_size, p->ranges), 84 masterPort(p->name + ".master", this, slavePort, p->delay, p->req_size), 85 ackWrites(p->write_ack), _params(p) | 79 slavePort(p->name + ".slave", *this, masterPort, p->delay, p->resp_size, 80 p->ranges), 81 masterPort(p->name + ".master", *this, slavePort, p->delay, p->req_size) |
86{ | 82{ |
87 if (ackWrites) 88 panic("No support for acknowledging writes\n"); | |
89} 90 91MasterPort& 92Bridge::getMasterPort(const std::string &if_name, int idx) 93{ 94 if (if_name == "master") 95 return masterPort; 96 else --- 31 unchanged lines hidden (view full) --- 128Bridge::BridgeSlavePort::respQueueFull() 129{ 130 return outstandingResponses == respQueueLimit; 131} 132 133bool 134Bridge::BridgeMasterPort::reqQueueFull() 135{ | 83} 84 85MasterPort& 86Bridge::getMasterPort(const std::string &if_name, int idx) 87{ 88 if (if_name == "master") 89 return masterPort; 90 else --- 31 unchanged lines hidden (view full) --- 122Bridge::BridgeSlavePort::respQueueFull() 123{ 124 return outstandingResponses == respQueueLimit; 125} 126 127bool 128Bridge::BridgeMasterPort::reqQueueFull() 129{ |
136 return requestQueue.size() == reqQueueLimit; | 130 return transmitList.size() == reqQueueLimit; |
137} 138 139bool 140Bridge::BridgeMasterPort::recvTimingResp(PacketPtr pkt) 141{ 142 // all checks are done when the request is accepted on the slave 143 // side, so we are guaranteed to have space for the response | 131} 132 133bool 134Bridge::BridgeMasterPort::recvTimingResp(PacketPtr pkt) 135{ 136 // all checks are done when the request is accepted on the slave 137 // side, so we are guaranteed to have space for the response |
144 DPRINTF(BusBridge, "recvTiming: response %s addr 0x%x\n", | 138 DPRINTF(Bridge, "recvTimingResp: %s addr 0x%x\n", |
145 pkt->cmdString(), pkt->getAddr()); 146 | 139 pkt->cmdString(), pkt->getAddr()); 140 |
147 DPRINTF(BusBridge, "Request queue size: %d\n", requestQueue.size()); | 141 DPRINTF(Bridge, "Request queue size: %d\n", transmitList.size()); |
148 | 142 |
149 slavePort.queueForSendTiming(pkt); | 143 slavePort.schedTimingResp(pkt, curTick() + delay); |
150 151 return true; 152} 153 154bool 155Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt) 156{ | 144 145 return true; 146} 147 148bool 149Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt) 150{ |
157 DPRINTF(BusBridge, "recvTiming: request %s addr 0x%x\n", | 151 DPRINTF(Bridge, "recvTimingReq: %s addr 0x%x\n", |
158 pkt->cmdString(), pkt->getAddr()); 159 | 152 pkt->cmdString(), pkt->getAddr()); 153 |
160 DPRINTF(BusBridge, "Response queue size: %d outresp: %d\n", 161 responseQueue.size(), outstandingResponses); | 154 // ensure we do not have something waiting to retry 155 if(retryReq) 156 return false; |
162 | 157 |
163 if (masterPort.reqQueueFull()) { 164 DPRINTF(BusBridge, "Request queue full, nacking\n"); 165 nackRequest(pkt); 166 return true; 167 } | 158 DPRINTF(Bridge, "Response queue size: %d outresp: %d\n", 159 transmitList.size(), outstandingResponses); |
168 | 160 |
169 if (pkt->needsResponse()) { | 161 if (masterPort.reqQueueFull()) { 162 DPRINTF(Bridge, "Request queue full\n"); 163 retryReq = true; 164 } else if (pkt->needsResponse()) { |
170 if (respQueueFull()) { | 165 if (respQueueFull()) { |
171 DPRINTF(BusBridge, 172 "Response queue full, no space for response, nacking\n"); 173 DPRINTF(BusBridge, 174 "queue size: %d outstanding resp: %d\n", 175 responseQueue.size(), outstandingResponses); 176 nackRequest(pkt); 177 return true; | 166 DPRINTF(Bridge, "Response queue full\n"); 167 retryReq = true; |
178 } else { | 168 } else { |
179 DPRINTF(BusBridge, "Request Needs response, reserving space\n"); | 169 DPRINTF(Bridge, "Reserving space for response\n"); |
180 assert(outstandingResponses != respQueueLimit); 181 ++outstandingResponses; | 170 assert(outstandingResponses != respQueueLimit); 171 ++outstandingResponses; |
172 retryReq = false; 173 masterPort.schedTimingReq(pkt, curTick() + delay); |
|
182 } 183 } 184 | 174 } 175 } 176 |
185 masterPort.queueForSendTiming(pkt); 186 187 return true; | 177 // remember that we are now stalling a packet and that we have to 178 // tell the sending master to retry once space becomes available, 179 // we make no distinction whether the stalling is due to the 180 // request queue or response queue being full 181 return !retryReq; |
188} 189 190void | 182} 183 184void |
191Bridge::BridgeSlavePort::nackRequest(PacketPtr pkt) | 185Bridge::BridgeSlavePort::retryStalledReq() |
192{ | 186{ |
193 // Nack the packet 194 pkt->makeTimingResponse(); 195 pkt->setNacked(); 196 197 // The Nack packets are stored in the response queue just like any 198 // other response, but they do not occupy any space as this is 199 // tracked by the outstandingResponses, this guarantees space for 200 // the Nack packets, but implicitly means we have an (unrealistic) 201 // unbounded Nack queue. 202 203 // put it on the list to send 204 Tick readyTime = curTick() + nackDelay; 205 DeferredResponse resp(pkt, readyTime, true); 206 207 // nothing on the list, add it and we're done 208 if (responseQueue.empty()) { 209 assert(!sendEvent.scheduled()); 210 bridge->schedule(sendEvent, readyTime); 211 responseQueue.push_back(resp); 212 return; | 187 if (retryReq) { 188 DPRINTF(Bridge, "Request waiting for retry, now retrying\n"); 189 retryReq = false; 190 sendRetry(); |
213 } | 191 } |
214 215 assert(sendEvent.scheduled() || inRetry); 216 217 // does it go at the end? 218 if (readyTime >= responseQueue.back().ready) { 219 responseQueue.push_back(resp); 220 return; 221 } 222 223 // ok, somewhere in the middle, fun 224 std::list<DeferredResponse>::iterator i = responseQueue.begin(); 225 std::list<DeferredResponse>::iterator end = responseQueue.end(); 226 std::list<DeferredResponse>::iterator begin = responseQueue.begin(); 227 bool done = false; 228 229 while (i != end && !done) { 230 if (readyTime < (*i).ready) { 231 if (i == begin) 232 bridge->reschedule(sendEvent, readyTime); 233 responseQueue.insert(i, resp); 234 done = true; 235 } 236 i++; 237 } 238 assert(done); | |
239} 240 241void | 192} 193 194void |
242Bridge::BridgeMasterPort::queueForSendTiming(PacketPtr pkt) | 195Bridge::BridgeMasterPort::schedTimingReq(PacketPtr pkt, Tick when) |
243{ | 196{ |
244 Tick readyTime = curTick() + delay; 245 | |
246 // If we expect to see a response, we need to restore the source 247 // and destination field that is potentially changed by a second 248 // bus 249 if (!pkt->memInhibitAsserted() && pkt->needsResponse()) { 250 // Update the sender state so we can deal with the response 251 // appropriately 252 RequestState *req_state = new RequestState(pkt); 253 pkt->senderState = req_state; 254 } 255 256 // If we're about to put this packet at the head of the queue, we 257 // need to schedule an event to do the transmit. Otherwise there 258 // should already be an event scheduled for sending the head 259 // packet. | 197 // If we expect to see a response, we need to restore the source 198 // and destination field that is potentially changed by a second 199 // bus 200 if (!pkt->memInhibitAsserted() && pkt->needsResponse()) { 201 // Update the sender state so we can deal with the response 202 // appropriately 203 RequestState *req_state = new RequestState(pkt); 204 pkt->senderState = req_state; 205 } 206 207 // If we're about to put this packet at the head of the queue, we 208 // need to schedule an event to do the transmit. Otherwise there 209 // should already be an event scheduled for sending the head 210 // packet. |
260 if (requestQueue.empty()) { 261 bridge->schedule(sendEvent, readyTime); | 211 if (transmitList.empty()) { 212 bridge.schedule(sendEvent, when); |
262 } 263 | 213 } 214 |
264 assert(requestQueue.size() != reqQueueLimit); | 215 assert(transmitList.size() != reqQueueLimit); |
265 | 216 |
266 requestQueue.push_back(DeferredRequest(pkt, readyTime)); | 217 transmitList.push_back(DeferredPacket(pkt, when)); |
267} 268 269 270void | 218} 219 220 221void |
271Bridge::BridgeSlavePort::queueForSendTiming(PacketPtr pkt) | 222Bridge::BridgeSlavePort::schedTimingResp(PacketPtr pkt, Tick when) |
272{ 273 // This is a response for a request we forwarded earlier. The 274 // corresponding request state should be stored in the packet's 275 // senderState field. 276 RequestState *req_state = dynamic_cast<RequestState*>(pkt->senderState); 277 assert(req_state != NULL); 278 // set up new packet dest & senderState based on values saved 279 // from original request 280 req_state->fixResponse(pkt); | 223{ 224 // This is a response for a request we forwarded earlier. The 225 // corresponding request state should be stored in the packet's 226 // senderState field. 227 RequestState *req_state = dynamic_cast<RequestState*>(pkt->senderState); 228 assert(req_state != NULL); 229 // set up new packet dest & senderState based on values saved 230 // from original request 231 req_state->fixResponse(pkt); |
232 delete req_state; |
|
281 282 // the bridge assumes that at least one bus has set the 283 // destination field of the packet 284 assert(pkt->isDestValid()); | 233 234 // the bridge assumes that at least one bus has set the 235 // destination field of the packet 236 assert(pkt->isDestValid()); |
285 DPRINTF(BusBridge, "response, new dest %d\n", pkt->getDest()); 286 delete req_state; | 237 DPRINTF(Bridge, "response, new dest %d\n", pkt->getDest()); |
287 | 238 |
288 Tick readyTime = curTick() + delay; 289 | |
290 // If we're about to put this packet at the head of the queue, we 291 // need to schedule an event to do the transmit. Otherwise there 292 // should already be an event scheduled for sending the head 293 // packet. | 239 // If we're about to put this packet at the head of the queue, we 240 // need to schedule an event to do the transmit. Otherwise there 241 // should already be an event scheduled for sending the head 242 // packet. |
294 if (responseQueue.empty()) { 295 bridge->schedule(sendEvent, readyTime); | 243 if (transmitList.empty()) { 244 bridge.schedule(sendEvent, when); |
296 } | 245 } |
297 responseQueue.push_back(DeferredResponse(pkt, readyTime)); | 246 247 transmitList.push_back(DeferredPacket(pkt, when)); |
298} 299 300void | 248} 249 250void |
301Bridge::BridgeMasterPort::trySend() | 251Bridge::BridgeMasterPort::trySendTiming() |
302{ | 252{ |
303 assert(!requestQueue.empty()); | 253 assert(!transmitList.empty()); |
304 | 254 |
305 DeferredRequest req = requestQueue.front(); | 255 DeferredPacket req = transmitList.front(); |
306 | 256 |
307 assert(req.ready <= curTick()); | 257 assert(req.tick <= curTick()); |
308 309 PacketPtr pkt = req.pkt; 310 | 258 259 PacketPtr pkt = req.pkt; 260 |
311 DPRINTF(BusBridge, "trySend request: addr 0x%x\n", pkt->getAddr()); | 261 DPRINTF(Bridge, "trySend request addr 0x%x, queue size %d\n", 262 pkt->getAddr(), transmitList.size()); |
312 313 if (sendTimingReq(pkt)) { 314 // send successful | 263 264 if (sendTimingReq(pkt)) { 265 // send successful |
315 requestQueue.pop_front(); | 266 transmitList.pop_front(); 267 DPRINTF(Bridge, "trySend request successful\n"); |
316 317 // If there are more packets to send, schedule event to try again. | 268 269 // If there are more packets to send, schedule event to try again. |
318 if (!requestQueue.empty()) { 319 req = requestQueue.front(); 320 DPRINTF(BusBridge, "Scheduling next send\n"); 321 bridge->schedule(sendEvent, 322 std::max(req.ready, curTick() + 1)); | 270 if (!transmitList.empty()) { 271 req = transmitList.front(); 272 DPRINTF(Bridge, "Scheduling next send\n"); 273 bridge.schedule(sendEvent, std::max(req.tick, 274 bridge.nextCycle())); |
323 } | 275 } |
324 } else { 325 inRetry = true; | 276 277 // if we have stalled a request due to a full request queue, 278 // then send a retry at this point, also note that if the 279 // request we stalled was waiting for the response queue 280 // rather than the request queue we might stall it again 281 slavePort.retryStalledReq(); |
326 } 327 | 282 } 283 |
328 DPRINTF(BusBridge, "trySend: request queue size: %d\n", 329 requestQueue.size()); | 284 // if the send failed, then we try again once we receive a retry, 285 // and therefore there is no need to take any action |
330} 331 332void | 286} 287 288void |
333Bridge::BridgeSlavePort::trySend() | 289Bridge::BridgeSlavePort::trySendTiming() |
334{ | 290{ |
335 assert(!responseQueue.empty()); | 291 assert(!transmitList.empty()); |
336 | 292 |
337 DeferredResponse resp = responseQueue.front(); | 293 DeferredPacket resp = transmitList.front(); |
338 | 294 |
339 assert(resp.ready <= curTick()); | 295 assert(resp.tick <= curTick()); |
340 341 PacketPtr pkt = resp.pkt; 342 | 296 297 PacketPtr pkt = resp.pkt; 298 |
343 DPRINTF(BusBridge, "trySend response: dest %d addr 0x%x\n", 344 pkt->getDest(), pkt->getAddr()); | 299 DPRINTF(Bridge, "trySend response addr 0x%x, outstanding %d\n", 300 pkt->getAddr(), outstandingResponses); |
345 | 301 |
346 bool was_nacked_here = resp.nackedHere; 347 | |
348 if (sendTimingResp(pkt)) { | 302 if (sendTimingResp(pkt)) { |
349 DPRINTF(BusBridge, " successful\n"); | |
350 // send successful | 303 // send successful |
351 responseQueue.pop_front(); | 304 transmitList.pop_front(); 305 DPRINTF(Bridge, "trySend response successful\n"); |
352 | 306 |
353 if (!was_nacked_here) { 354 assert(outstandingResponses != 0); 355 --outstandingResponses; 356 } | 307 assert(outstandingResponses != 0); 308 --outstandingResponses; |
357 358 // If there are more packets to send, schedule event to try again. | 309 310 // If there are more packets to send, schedule event to try again. |
359 if (!responseQueue.empty()) { 360 resp = responseQueue.front(); 361 DPRINTF(BusBridge, "Scheduling next send\n"); 362 bridge->schedule(sendEvent, 363 std::max(resp.ready, curTick() + 1)); | 311 if (!transmitList.empty()) { 312 resp = transmitList.front(); 313 DPRINTF(Bridge, "Scheduling next send\n"); 314 bridge.schedule(sendEvent, std::max(resp.tick, 315 bridge.nextCycle())); |
364 } | 316 } |
365 } else { 366 DPRINTF(BusBridge, " unsuccessful\n"); 367 inRetry = true; | 317 318 // if there is space in the request queue and we were stalling 319 // a request, it will definitely be possible to accept it now 320 // since there is guaranteed space in the response queue 321 if (!masterPort.reqQueueFull() && retryReq) { 322 DPRINTF(Bridge, "Request waiting for retry, now retrying\n"); 323 retryReq = false; 324 sendRetry(); 325 } |
368 } 369 | 326 } 327 |
370 DPRINTF(BusBridge, "trySend: queue size: %d outstanding resp: %d\n", 371 responseQueue.size(), outstandingResponses); | 328 // if the send failed, then we try again once we receive a retry, 329 // and therefore there is no need to take any action |
372} 373 374void 375Bridge::BridgeMasterPort::recvRetry() 376{ | 330} 331 332void 333Bridge::BridgeMasterPort::recvRetry() 334{ |
377 inRetry = false; 378 Tick nextReady = requestQueue.front().ready; | 335 Tick nextReady = transmitList.front().tick; |
379 if (nextReady <= curTick()) | 336 if (nextReady <= curTick()) |
380 trySend(); | 337 trySendTiming(); |
381 else | 338 else |
382 bridge->schedule(sendEvent, nextReady); | 339 bridge.schedule(sendEvent, nextReady); |
383} 384 385void 386Bridge::BridgeSlavePort::recvRetry() 387{ | 340} 341 342void 343Bridge::BridgeSlavePort::recvRetry() 344{ |
388 inRetry = false; 389 Tick nextReady = responseQueue.front().ready; | 345 Tick nextReady = transmitList.front().tick; |
390 if (nextReady <= curTick()) | 346 if (nextReady <= curTick()) |
391 trySend(); | 347 trySendTiming(); |
392 else | 348 else |
393 bridge->schedule(sendEvent, nextReady); | 349 bridge.schedule(sendEvent, nextReady); |
394} 395 396Tick 397Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt) 398{ 399 return delay + masterPort.sendAtomic(pkt); 400} 401 402void 403Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt) 404{ | 350} 351 352Tick 353Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt) 354{ 355 return delay + masterPort.sendAtomic(pkt); 356} 357 358void 359Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt) 360{ |
405 std::list<DeferredResponse>::iterator i; | 361 std::list<DeferredPacket>::iterator i; |
406 407 pkt->pushLabel(name()); 408 409 // check the response queue | 362 363 pkt->pushLabel(name()); 364 365 // check the response queue |
410 for (i = responseQueue.begin(); i != responseQueue.end(); ++i) { | 366 for (i = transmitList.begin(); i != transmitList.end(); ++i) { |
411 if (pkt->checkFunctional((*i).pkt)) { 412 pkt->makeResponse(); 413 return; 414 } 415 } 416 417 // also check the master port's request queue 418 if (masterPort.checkFunctional(pkt)) { --- 5 unchanged lines hidden (view full) --- 424 // fall through if pkt still not satisfied 425 masterPort.sendFunctional(pkt); 426} 427 428bool 429Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt) 430{ 431 bool found = false; | 367 if (pkt->checkFunctional((*i).pkt)) { 368 pkt->makeResponse(); 369 return; 370 } 371 } 372 373 // also check the master port's request queue 374 if (masterPort.checkFunctional(pkt)) { --- 5 unchanged lines hidden (view full) --- 380 // fall through if pkt still not satisfied 381 masterPort.sendFunctional(pkt); 382} 383 384bool 385Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt) 386{ 387 bool found = false; |
432 std::list<DeferredRequest>::iterator i = requestQueue.begin(); | 388 std::list<DeferredPacket>::iterator i = transmitList.begin(); |
433 | 389 |
434 while(i != requestQueue.end() && !found) { | 390 while(i != transmitList.end() && !found) { |
435 if (pkt->checkFunctional((*i).pkt)) { 436 pkt->makeResponse(); 437 found = true; 438 } 439 ++i; 440 } 441 442 return found; --- 13 unchanged lines hidden --- | 391 if (pkt->checkFunctional((*i).pkt)) { 392 pkt->makeResponse(); 393 found = true; 394 } 395 ++i; 396 } 397 398 return found; --- 13 unchanged lines hidden --- |