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 * Steve Reinhardt
42 * Andreas Hansson
43 */
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 Cycles _delay, int _resp_limit,
| 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 * Steve Reinhardt
42 * Andreas Hansson
43 */
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 Cycles _delay, int _resp_limit,
|
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 Cycles _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,
80 ticksToCycles(p->delay), p->resp_size, p->ranges),
81 masterPort(p->name + ".master", *this, slavePort,
82 ticksToCycles(p->delay), p->req_size)
83{
84}
85
86MasterPort&
87Bridge::getMasterPort(const std::string &if_name, int idx)
88{
89 if (if_name == "master")
90 return masterPort;
91 else
92 // pass it along to our super class
93 return MemObject::getMasterPort(if_name, idx);
94}
95
96SlavePort&
97Bridge::getSlavePort(const std::string &if_name, int idx)
98{
99 if (if_name == "slave")
100 return slavePort;
101 else
102 // pass it along to our super class
103 return MemObject::getSlavePort(if_name, idx);
104}
105
106void
107Bridge::init()
108{
109 // make sure both sides are connected and have the same block size
110 if (!slavePort.isConnected() || !masterPort.isConnected())
111 fatal("Both ports of bus bridge are not connected to a bus.\n");
112
113 if (slavePort.peerBlockSize() != masterPort.peerBlockSize())
114 fatal("Slave port size %d, master port size %d \n " \
115 "Busses don't have the same block size... Not supported.\n",
116 slavePort.peerBlockSize(), masterPort.peerBlockSize());
117
118 // notify the master side of our address ranges
119 slavePort.sendRangeChange();
120}
121
122bool
123Bridge::BridgeSlavePort::respQueueFull()
124{
125 return outstandingResponses == respQueueLimit;
126}
127
128bool
129Bridge::BridgeMasterPort::reqQueueFull()
130{
131 return transmitList.size() == reqQueueLimit;
132}
133
134bool
135Bridge::BridgeMasterPort::recvTimingResp(PacketPtr pkt)
136{
137 // all checks are done when the request is accepted on the slave
138 // side, so we are guaranteed to have space for the response
139 DPRINTF(Bridge, "recvTimingResp: %s addr 0x%x\n",
140 pkt->cmdString(), pkt->getAddr());
141
142 DPRINTF(Bridge, "Request queue size: %d\n", transmitList.size());
143
144 slavePort.schedTimingResp(pkt, bridge.clockEdge(delay));
145
146 return true;
147}
148
149bool
150Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt)
151{
152 DPRINTF(Bridge, "recvTimingReq: %s addr 0x%x\n",
153 pkt->cmdString(), pkt->getAddr());
154
155 // ensure we do not have something waiting to retry
156 if(retryReq)
157 return false;
158
159 DPRINTF(Bridge, "Response queue size: %d outresp: %d\n",
160 transmitList.size(), outstandingResponses);
161
162 if (masterPort.reqQueueFull()) {
163 DPRINTF(Bridge, "Request queue full\n");
164 retryReq = true;
165 } else if (pkt->needsResponse()) {
166 if (respQueueFull()) {
167 DPRINTF(Bridge, "Response queue full\n");
168 retryReq = true;
169 } else {
170 DPRINTF(Bridge, "Reserving space for response\n");
171 assert(outstandingResponses != respQueueLimit);
172 ++outstandingResponses;
173 retryReq = false;
174 masterPort.schedTimingReq(pkt, bridge.clockEdge(delay));
175 }
176 }
177
178 // remember that we are now stalling a packet and that we have to
179 // tell the sending master to retry once space becomes available,
180 // we make no distinction whether the stalling is due to the
181 // request queue or response queue being full
182 return !retryReq;
183}
184
185void
186Bridge::BridgeSlavePort::retryStalledReq()
187{
188 if (retryReq) {
189 DPRINTF(Bridge, "Request waiting for retry, now retrying\n");
190 retryReq = false;
191 sendRetry();
192 }
193}
194
195void
196Bridge::BridgeMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
197{
198 // If we expect to see a response, we need to restore the source
199 // and destination field that is potentially changed by a second
200 // bus
201 if (!pkt->memInhibitAsserted() && pkt->needsResponse()) {
202 // Update the sender state so we can deal with the response
203 // appropriately
204 RequestState *req_state = new RequestState(pkt);
205 pkt->senderState = req_state;
206 }
207
208 // If we're about to put this packet at the head of the queue, we
209 // need to schedule an event to do the transmit. Otherwise there
210 // should already be an event scheduled for sending the head
211 // packet.
212 if (transmitList.empty()) {
213 bridge.schedule(sendEvent, when);
214 }
215
216 assert(transmitList.size() != reqQueueLimit);
217
218 transmitList.push_back(DeferredPacket(pkt, when));
219}
220
221
222void
223Bridge::BridgeSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
224{
225 // This is a response for a request we forwarded earlier. The
226 // corresponding request state should be stored in the packet's
227 // senderState field.
228 RequestState *req_state = dynamic_cast<RequestState*>(pkt->senderState);
229 assert(req_state != NULL);
230 // set up new packet dest & senderState based on values saved
231 // from original request
232 req_state->fixResponse(pkt);
233 delete req_state;
234
235 // the bridge assumes that at least one bus has set the
236 // destination field of the packet
237 assert(pkt->isDestValid());
238 DPRINTF(Bridge, "response, new dest %d\n", pkt->getDest());
239
240 // If we're about to put this packet at the head of the queue, we
241 // need to schedule an event to do the transmit. Otherwise there
242 // should already be an event scheduled for sending the head
243 // packet.
244 if (transmitList.empty()) {
245 bridge.schedule(sendEvent, when);
246 }
247
248 transmitList.push_back(DeferredPacket(pkt, when));
249}
250
251void
252Bridge::BridgeMasterPort::trySendTiming()
253{
254 assert(!transmitList.empty());
255
256 DeferredPacket req = transmitList.front();
257
258 assert(req.tick <= curTick());
259
260 PacketPtr pkt = req.pkt;
261
262 DPRINTF(Bridge, "trySend request addr 0x%x, queue size %d\n",
263 pkt->getAddr(), transmitList.size());
264
265 if (sendTimingReq(pkt)) {
266 // send successful
267 transmitList.pop_front();
268 DPRINTF(Bridge, "trySend request successful\n");
269
270 // If there are more packets to send, schedule event to try again.
271 if (!transmitList.empty()) {
272 req = transmitList.front();
273 DPRINTF(Bridge, "Scheduling next send\n");
274 bridge.schedule(sendEvent, std::max(req.tick,
275 bridge.nextCycle()));
276 }
277
278 // if we have stalled a request due to a full request queue,
279 // then send a retry at this point, also note that if the
280 // request we stalled was waiting for the response queue
281 // rather than the request queue we might stall it again
282 slavePort.retryStalledReq();
283 }
284
285 // if the send failed, then we try again once we receive a retry,
286 // and therefore there is no need to take any action
287}
288
289void
290Bridge::BridgeSlavePort::trySendTiming()
291{
292 assert(!transmitList.empty());
293
294 DeferredPacket resp = transmitList.front();
295
296 assert(resp.tick <= curTick());
297
298 PacketPtr pkt = resp.pkt;
299
300 DPRINTF(Bridge, "trySend response addr 0x%x, outstanding %d\n",
301 pkt->getAddr(), outstandingResponses);
302
303 if (sendTimingResp(pkt)) {
304 // send successful
305 transmitList.pop_front();
306 DPRINTF(Bridge, "trySend response successful\n");
307
308 assert(outstandingResponses != 0);
309 --outstandingResponses;
310
311 // If there are more packets to send, schedule event to try again.
312 if (!transmitList.empty()) {
313 resp = transmitList.front();
314 DPRINTF(Bridge, "Scheduling next send\n");
315 bridge.schedule(sendEvent, std::max(resp.tick,
316 bridge.nextCycle()));
317 }
318
319 // if there is space in the request queue and we were stalling
320 // a request, it will definitely be possible to accept it now
321 // since there is guaranteed space in the response queue
322 if (!masterPort.reqQueueFull() && retryReq) {
323 DPRINTF(Bridge, "Request waiting for retry, now retrying\n");
324 retryReq = false;
325 sendRetry();
326 }
327 }
328
329 // if the send failed, then we try again once we receive a retry,
330 // and therefore there is no need to take any action
331}
332
333void
334Bridge::BridgeMasterPort::recvRetry()
335{
336 Tick nextReady = transmitList.front().tick;
337 if (nextReady <= curTick())
338 trySendTiming();
339 else
340 bridge.schedule(sendEvent, nextReady);
341}
342
343void
344Bridge::BridgeSlavePort::recvRetry()
345{
346 Tick nextReady = transmitList.front().tick;
347 if (nextReady <= curTick())
348 trySendTiming();
349 else
350 bridge.schedule(sendEvent, nextReady);
351}
352
353Tick
354Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt)
355{
356 return delay * bridge.clockPeriod() + masterPort.sendAtomic(pkt);
357}
358
359void
360Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt)
361{
362 std::list<DeferredPacket>::iterator i;
363
364 pkt->pushLabel(name());
365
366 // check the response queue
367 for (i = transmitList.begin(); i != transmitList.end(); ++i) {
368 if (pkt->checkFunctional((*i).pkt)) {
369 pkt->makeResponse();
370 return;
371 }
372 }
373
374 // also check the master port's request queue
375 if (masterPort.checkFunctional(pkt)) {
376 return;
377 }
378
379 pkt->popLabel();
380
381 // fall through if pkt still not satisfied
382 masterPort.sendFunctional(pkt);
383}
384
385bool
386Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt)
387{
388 bool found = false;
389 std::list<DeferredPacket>::iterator i = transmitList.begin();
390
391 while(i != transmitList.end() && !found) {
392 if (pkt->checkFunctional((*i).pkt)) {
393 pkt->makeResponse();
394 found = true;
395 }
396 ++i;
397 }
398
399 return found;
400}
401
402AddrRangeList
403Bridge::BridgeSlavePort::getAddrRanges() const
404{
405 return ranges;
406}
407
408Bridge *
409BridgeParams::create()
410{
411 return new Bridge(this);
412}
| 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 Cycles _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,
80 ticksToCycles(p->delay), p->resp_size, p->ranges),
81 masterPort(p->name + ".master", *this, slavePort,
82 ticksToCycles(p->delay), p->req_size)
83{
84}
85
86MasterPort&
87Bridge::getMasterPort(const std::string &if_name, int idx)
88{
89 if (if_name == "master")
90 return masterPort;
91 else
92 // pass it along to our super class
93 return MemObject::getMasterPort(if_name, idx);
94}
95
96SlavePort&
97Bridge::getSlavePort(const std::string &if_name, int idx)
98{
99 if (if_name == "slave")
100 return slavePort;
101 else
102 // pass it along to our super class
103 return MemObject::getSlavePort(if_name, idx);
104}
105
106void
107Bridge::init()
108{
109 // make sure both sides are connected and have the same block size
110 if (!slavePort.isConnected() || !masterPort.isConnected())
111 fatal("Both ports of bus bridge are not connected to a bus.\n");
112
113 if (slavePort.peerBlockSize() != masterPort.peerBlockSize())
114 fatal("Slave port size %d, master port size %d \n " \
115 "Busses don't have the same block size... Not supported.\n",
116 slavePort.peerBlockSize(), masterPort.peerBlockSize());
117
118 // notify the master side of our address ranges
119 slavePort.sendRangeChange();
120}
121
122bool
123Bridge::BridgeSlavePort::respQueueFull()
124{
125 return outstandingResponses == respQueueLimit;
126}
127
128bool
129Bridge::BridgeMasterPort::reqQueueFull()
130{
131 return transmitList.size() == reqQueueLimit;
132}
133
134bool
135Bridge::BridgeMasterPort::recvTimingResp(PacketPtr pkt)
136{
137 // all checks are done when the request is accepted on the slave
138 // side, so we are guaranteed to have space for the response
139 DPRINTF(Bridge, "recvTimingResp: %s addr 0x%x\n",
140 pkt->cmdString(), pkt->getAddr());
141
142 DPRINTF(Bridge, "Request queue size: %d\n", transmitList.size());
143
144 slavePort.schedTimingResp(pkt, bridge.clockEdge(delay));
145
146 return true;
147}
148
149bool
150Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt)
151{
152 DPRINTF(Bridge, "recvTimingReq: %s addr 0x%x\n",
153 pkt->cmdString(), pkt->getAddr());
154
155 // ensure we do not have something waiting to retry
156 if(retryReq)
157 return false;
158
159 DPRINTF(Bridge, "Response queue size: %d outresp: %d\n",
160 transmitList.size(), outstandingResponses);
161
162 if (masterPort.reqQueueFull()) {
163 DPRINTF(Bridge, "Request queue full\n");
164 retryReq = true;
165 } else if (pkt->needsResponse()) {
166 if (respQueueFull()) {
167 DPRINTF(Bridge, "Response queue full\n");
168 retryReq = true;
169 } else {
170 DPRINTF(Bridge, "Reserving space for response\n");
171 assert(outstandingResponses != respQueueLimit);
172 ++outstandingResponses;
173 retryReq = false;
174 masterPort.schedTimingReq(pkt, bridge.clockEdge(delay));
175 }
176 }
177
178 // remember that we are now stalling a packet and that we have to
179 // tell the sending master to retry once space becomes available,
180 // we make no distinction whether the stalling is due to the
181 // request queue or response queue being full
182 return !retryReq;
183}
184
185void
186Bridge::BridgeSlavePort::retryStalledReq()
187{
188 if (retryReq) {
189 DPRINTF(Bridge, "Request waiting for retry, now retrying\n");
190 retryReq = false;
191 sendRetry();
192 }
193}
194
195void
196Bridge::BridgeMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
197{
198 // If we expect to see a response, we need to restore the source
199 // and destination field that is potentially changed by a second
200 // bus
201 if (!pkt->memInhibitAsserted() && pkt->needsResponse()) {
202 // Update the sender state so we can deal with the response
203 // appropriately
204 RequestState *req_state = new RequestState(pkt);
205 pkt->senderState = req_state;
206 }
207
208 // If we're about to put this packet at the head of the queue, we
209 // need to schedule an event to do the transmit. Otherwise there
210 // should already be an event scheduled for sending the head
211 // packet.
212 if (transmitList.empty()) {
213 bridge.schedule(sendEvent, when);
214 }
215
216 assert(transmitList.size() != reqQueueLimit);
217
218 transmitList.push_back(DeferredPacket(pkt, when));
219}
220
221
222void
223Bridge::BridgeSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
224{
225 // This is a response for a request we forwarded earlier. The
226 // corresponding request state should be stored in the packet's
227 // senderState field.
228 RequestState *req_state = dynamic_cast<RequestState*>(pkt->senderState);
229 assert(req_state != NULL);
230 // set up new packet dest & senderState based on values saved
231 // from original request
232 req_state->fixResponse(pkt);
233 delete req_state;
234
235 // the bridge assumes that at least one bus has set the
236 // destination field of the packet
237 assert(pkt->isDestValid());
238 DPRINTF(Bridge, "response, new dest %d\n", pkt->getDest());
239
240 // If we're about to put this packet at the head of the queue, we
241 // need to schedule an event to do the transmit. Otherwise there
242 // should already be an event scheduled for sending the head
243 // packet.
244 if (transmitList.empty()) {
245 bridge.schedule(sendEvent, when);
246 }
247
248 transmitList.push_back(DeferredPacket(pkt, when));
249}
250
251void
252Bridge::BridgeMasterPort::trySendTiming()
253{
254 assert(!transmitList.empty());
255
256 DeferredPacket req = transmitList.front();
257
258 assert(req.tick <= curTick());
259
260 PacketPtr pkt = req.pkt;
261
262 DPRINTF(Bridge, "trySend request addr 0x%x, queue size %d\n",
263 pkt->getAddr(), transmitList.size());
264
265 if (sendTimingReq(pkt)) {
266 // send successful
267 transmitList.pop_front();
268 DPRINTF(Bridge, "trySend request successful\n");
269
270 // If there are more packets to send, schedule event to try again.
271 if (!transmitList.empty()) {
272 req = transmitList.front();
273 DPRINTF(Bridge, "Scheduling next send\n");
274 bridge.schedule(sendEvent, std::max(req.tick,
275 bridge.nextCycle()));
276 }
277
278 // if we have stalled a request due to a full request queue,
279 // then send a retry at this point, also note that if the
280 // request we stalled was waiting for the response queue
281 // rather than the request queue we might stall it again
282 slavePort.retryStalledReq();
283 }
284
285 // if the send failed, then we try again once we receive a retry,
286 // and therefore there is no need to take any action
287}
288
289void
290Bridge::BridgeSlavePort::trySendTiming()
291{
292 assert(!transmitList.empty());
293
294 DeferredPacket resp = transmitList.front();
295
296 assert(resp.tick <= curTick());
297
298 PacketPtr pkt = resp.pkt;
299
300 DPRINTF(Bridge, "trySend response addr 0x%x, outstanding %d\n",
301 pkt->getAddr(), outstandingResponses);
302
303 if (sendTimingResp(pkt)) {
304 // send successful
305 transmitList.pop_front();
306 DPRINTF(Bridge, "trySend response successful\n");
307
308 assert(outstandingResponses != 0);
309 --outstandingResponses;
310
311 // If there are more packets to send, schedule event to try again.
312 if (!transmitList.empty()) {
313 resp = transmitList.front();
314 DPRINTF(Bridge, "Scheduling next send\n");
315 bridge.schedule(sendEvent, std::max(resp.tick,
316 bridge.nextCycle()));
317 }
318
319 // if there is space in the request queue and we were stalling
320 // a request, it will definitely be possible to accept it now
321 // since there is guaranteed space in the response queue
322 if (!masterPort.reqQueueFull() && retryReq) {
323 DPRINTF(Bridge, "Request waiting for retry, now retrying\n");
324 retryReq = false;
325 sendRetry();
326 }
327 }
328
329 // if the send failed, then we try again once we receive a retry,
330 // and therefore there is no need to take any action
331}
332
333void
334Bridge::BridgeMasterPort::recvRetry()
335{
336 Tick nextReady = transmitList.front().tick;
337 if (nextReady <= curTick())
338 trySendTiming();
339 else
340 bridge.schedule(sendEvent, nextReady);
341}
342
343void
344Bridge::BridgeSlavePort::recvRetry()
345{
346 Tick nextReady = transmitList.front().tick;
347 if (nextReady <= curTick())
348 trySendTiming();
349 else
350 bridge.schedule(sendEvent, nextReady);
351}
352
353Tick
354Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt)
355{
356 return delay * bridge.clockPeriod() + masterPort.sendAtomic(pkt);
357}
358
359void
360Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt)
361{
362 std::list<DeferredPacket>::iterator i;
363
364 pkt->pushLabel(name());
365
366 // check the response queue
367 for (i = transmitList.begin(); i != transmitList.end(); ++i) {
368 if (pkt->checkFunctional((*i).pkt)) {
369 pkt->makeResponse();
370 return;
371 }
372 }
373
374 // also check the master port's request queue
375 if (masterPort.checkFunctional(pkt)) {
376 return;
377 }
378
379 pkt->popLabel();
380
381 // fall through if pkt still not satisfied
382 masterPort.sendFunctional(pkt);
383}
384
385bool
386Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt)
387{
388 bool found = false;
389 std::list<DeferredPacket>::iterator i = transmitList.begin();
390
391 while(i != transmitList.end() && !found) {
392 if (pkt->checkFunctional((*i).pkt)) {
393 pkt->makeResponse();
394 found = true;
395 }
396 ++i;
397 }
398
399 return found;
400}
401
402AddrRangeList
403Bridge::BridgeSlavePort::getAddrRanges() const
404{
405 return ranges;
406}
407
408Bridge *
409BridgeParams::create()
410{
411 return new Bridge(this);
412}
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