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/Bridge.hh" |
53#include "mem/bridge.hh" 54#include "params/Bridge.hh" 55 |
56Bridge::BridgeSlavePort::BridgeSlavePort(const std::string& _name, 57 Bridge& _bridge, |
58 BridgeMasterPort& _masterPort, |
59 int _delay, int _resp_limit, |
60 std::vector<Range<Addr> > _ranges) |
61 : SlavePort(_name, &_bridge), bridge(_bridge), masterPort(_masterPort), 62 delay(_delay), ranges(_ranges.begin(), _ranges.end()), 63 outstandingResponses(0), retryReq(false), |
64 respQueueLimit(_resp_limit), sendEvent(*this) 65{ 66} 67 |
68Bridge::BridgeMasterPort::BridgeMasterPort(const std::string& _name, 69 Bridge& _bridge, |
70 BridgeSlavePort& _slavePort, 71 int _delay, int _req_limit) |
72 : MasterPort(_name, &_bridge), bridge(_bridge), slavePort(_slavePort), 73 delay(_delay), reqQueueLimit(_req_limit), sendEvent(*this) |
74{ 75} 76 77Bridge::Bridge(Params *p) 78 : MemObject(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) |
82{ |
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{ |
130 return transmitList.size() == reqQueueLimit; |
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 |
138 DPRINTF(Bridge, "recvTimingResp: %s addr 0x%x\n", |
139 pkt->cmdString(), pkt->getAddr()); 140 |
141 DPRINTF(Bridge, "Request queue size: %d\n", transmitList.size()); |
142 |
143 slavePort.schedTimingResp(pkt, curTick() + delay); |
144 145 return true; 146} 147 148bool 149Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt) 150{ |
151 DPRINTF(Bridge, "recvTimingReq: %s addr 0x%x\n", |
152 pkt->cmdString(), pkt->getAddr()); 153 |
154 // ensure we do not have something waiting to retry 155 if(retryReq) 156 return false; |
157 |
158 DPRINTF(Bridge, "Response queue size: %d outresp: %d\n", 159 transmitList.size(), outstandingResponses); |
160 |
161 if (masterPort.reqQueueFull()) { 162 DPRINTF(Bridge, "Request queue full\n"); 163 retryReq = true; 164 } else if (pkt->needsResponse()) { |
165 if (respQueueFull()) { |
166 DPRINTF(Bridge, "Response queue full\n"); 167 retryReq = true; |
168 } else { |
169 DPRINTF(Bridge, "Reserving space for response\n"); |
170 assert(outstandingResponses != respQueueLimit); 171 ++outstandingResponses; |
172 retryReq = false; 173 masterPort.schedTimingReq(pkt, curTick() + delay); |
174 } 175 } 176 |
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; |
182} 183 184void |
185Bridge::BridgeSlavePort::retryStalledReq() |
186{ |
187 if (retryReq) { 188 DPRINTF(Bridge, "Request waiting for retry, now retrying\n"); 189 retryReq = false; 190 sendRetry(); |
191 } |
192} 193 194void |
195Bridge::BridgeMasterPort::schedTimingReq(PacketPtr pkt, Tick when) |
196{ |
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. |
211 if (transmitList.empty()) { 212 bridge.schedule(sendEvent, when); |
213 } 214 |
215 assert(transmitList.size() != reqQueueLimit); |
216 |
217 transmitList.push_back(DeferredPacket(pkt, when)); |
218} 219 220 221void |
222Bridge::BridgeSlavePort::schedTimingResp(PacketPtr pkt, Tick when) |
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; |
233 234 // the bridge assumes that at least one bus has set the 235 // destination field of the packet 236 assert(pkt->isDestValid()); |
237 DPRINTF(Bridge, "response, new dest %d\n", pkt->getDest()); |
238 |
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. |
243 if (transmitList.empty()) { 244 bridge.schedule(sendEvent, when); |
245 } |
246 247 transmitList.push_back(DeferredPacket(pkt, when)); |
248} 249 250void |
251Bridge::BridgeMasterPort::trySendTiming() |
252{ |
253 assert(!transmitList.empty()); |
254 |
255 DeferredPacket req = transmitList.front(); |
256 |
257 assert(req.tick <= curTick()); |
258 259 PacketPtr pkt = req.pkt; 260 |
261 DPRINTF(Bridge, "trySend request addr 0x%x, queue size %d\n", 262 pkt->getAddr(), transmitList.size()); |
263 264 if (sendTimingReq(pkt)) { 265 // send successful |
266 transmitList.pop_front(); 267 DPRINTF(Bridge, "trySend request successful\n"); |
268 269 // If there are more packets to send, schedule event to try again. |
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())); |
275 } |
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(); |
282 } 283 |
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 |
286} 287 288void |
289Bridge::BridgeSlavePort::trySendTiming() |
290{ |
291 assert(!transmitList.empty()); |
292 |
293 DeferredPacket resp = transmitList.front(); |
294 |
295 assert(resp.tick <= curTick()); |
296 297 PacketPtr pkt = resp.pkt; 298 |
299 DPRINTF(Bridge, "trySend response addr 0x%x, outstanding %d\n", 300 pkt->getAddr(), outstandingResponses); |
301 |
302 if (sendTimingResp(pkt)) { |
303 // send successful |
304 transmitList.pop_front(); 305 DPRINTF(Bridge, "trySend response successful\n"); |
306 |
307 assert(outstandingResponses != 0); 308 --outstandingResponses; |
309 310 // If there are more packets to send, schedule event to try again. |
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())); |
316 } |
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 } |
326 } 327 |
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 |
330} 331 332void 333Bridge::BridgeMasterPort::recvRetry() 334{ |
335 Tick nextReady = transmitList.front().tick; |
336 if (nextReady <= curTick()) |
337 trySendTiming(); |
338 else |
339 bridge.schedule(sendEvent, nextReady); |
340} 341 342void 343Bridge::BridgeSlavePort::recvRetry() 344{ |
345 Tick nextReady = transmitList.front().tick; |
346 if (nextReady <= curTick()) |
347 trySendTiming(); |
348 else |
349 bridge.schedule(sendEvent, nextReady); |
350} 351 352Tick 353Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt) 354{ 355 return delay + masterPort.sendAtomic(pkt); 356} 357 358void 359Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt) 360{ |
361 std::list<DeferredPacket>::iterator i; |
362 363 pkt->pushLabel(name()); 364 365 // check the response queue |
366 for (i = transmitList.begin(); i != transmitList.end(); ++i) { |
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; |
388 std::list<DeferredPacket>::iterator i = transmitList.begin(); |
389 |
390 while(i != transmitList.end() && !found) { |
391 if (pkt->checkFunctional((*i).pkt)) { 392 pkt->makeResponse(); 393 found = true; 394 } 395 ++i; 396 } 397 398 return found; --- 13 unchanged lines hidden --- |