1/*
2 * Copyright (c) 2011-2013 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 * Copyright (c) 2015 The University of Bologna
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Ali Saidi
42 * Steve Reinhardt
43 * Andreas Hansson
44 * Erfan Azarkhish
45 */
46
47/**
48 * @file
49 * Implementation of the SerialLink Class, modeling Hybrid-Memory-Cube's
50 * serial interface.
51 */
52
53#include "mem/serial_link.hh"
54
55#include "base/trace.hh"
56#include "debug/SerialLink.hh"
57#include "params/SerialLink.hh"
58
59
60SerialLink::SerialLinkSlavePort::SerialLinkSlavePort(const std::string& _name,
61 SerialLink& _serial_link,
62 SerialLinkMasterPort& _masterPort,
63 Cycles _delay, int _resp_limit,
64 const std::vector<AddrRange>&
65 _ranges)
66 : SlavePort(_name, &_serial_link), serial_link(_serial_link),
67 masterPort(_masterPort), delay(_delay),
68 ranges(_ranges.begin(), _ranges.end()),
69 outstandingResponses(0), retryReq(false),
70 respQueueLimit(_resp_limit), sendEvent(*this)
71{
72}
73
74SerialLink::SerialLinkMasterPort::SerialLinkMasterPort(const std::string&
75 _name, SerialLink& _serial_link,
76 SerialLinkSlavePort& _slavePort,
77 Cycles _delay, int _req_limit)
78 : MasterPort(_name, &_serial_link), serial_link(_serial_link),
79 slavePort(_slavePort), delay(_delay), reqQueueLimit(_req_limit),
80 sendEvent(*this)
81{
82}
83
84SerialLink::SerialLink(SerialLinkParams *p)
85 : MemObject(p),
86 slavePort(p->name + ".slave", *this, masterPort,
87 ticksToCycles(p->delay), p->resp_size, p->ranges),
88 masterPort(p->name + ".master", *this, slavePort,
89 ticksToCycles(p->delay), p->req_size),
90 num_lanes(p->num_lanes)
91{
92}
93
94BaseMasterPort&
95SerialLink::getMasterPort(const std::string &if_name, PortID idx)
96{
97 if (if_name == "master")
98 return masterPort;
99 else
100 // pass it along to our super class
101 return MemObject::getMasterPort(if_name, idx);
102}
103
104BaseSlavePort&
105SerialLink::getSlavePort(const std::string &if_name, PortID idx)
106{
107 if (if_name == "slave")
108 return slavePort;
109 else
110 // pass it along to our super class
111 return MemObject::getSlavePort(if_name, idx);
112}
113
114void
115SerialLink::init()
116{
117 // make sure both sides are connected and have the same block size
118 if (!slavePort.isConnected() || !masterPort.isConnected())
119 fatal("Both ports of a serial_link must be connected.\n");
120
121 // notify the master side of our address ranges
122 slavePort.sendRangeChange();
123}
124
125bool
126SerialLink::SerialLinkSlavePort::respQueueFull() const
127{
128 return outstandingResponses == respQueueLimit;
129}
130
131bool
132SerialLink::SerialLinkMasterPort::reqQueueFull() const
133{
134 return transmitList.size() == reqQueueLimit;
135}
136
137bool
138SerialLink::SerialLinkMasterPort::recvTimingResp(PacketPtr pkt)
139{
140 // all checks are done when the request is accepted on the slave
141 // side, so we are guaranteed to have space for the response
142 DPRINTF(SerialLink, "recvTimingResp: %s addr 0x%x\n",
143 pkt->cmdString(), pkt->getAddr());
144
145 DPRINTF(SerialLink, "Request queue size: %d\n", transmitList.size());
146
147 // @todo: We need to pay for this and not just zero it out
148 pkt->headerDelay = pkt->payloadDelay = 0;
149
150 // This is similar to what happens for the request packets:
151 // The serializer will start serialization as soon as it receives the
152 // first flit, but the deserializer (at the host side in this case), will
153 // have to wait to receive the whole packet. So we only account for the
154 // deserialization latency.
155 Cycles cycles = delay;
156 cycles += Cycles(divCeil(pkt->getSize() * 8, serial_link.num_lanes));
157 Tick t = serial_link.clockEdge(cycles);
158
159 //@todo: If the processor sends two uncached requests towards HMC and the
160 // second one is smaller than the first one. It may happen that the second
161 // one crosses this link faster than the first one (because the packet
162 // waits in the link based on its size). This can reorder the received
163 // response.
164 slavePort.schedTimingResp(pkt, t);
165
166 return true;
167}
168
169bool
170SerialLink::SerialLinkSlavePort::recvTimingReq(PacketPtr pkt)
171{
172 DPRINTF(SerialLink, "recvTimingReq: %s addr 0x%x\n",
173 pkt->cmdString(), pkt->getAddr());
174
175 // we should not see a timing request if we are already in a retry
176 assert(!retryReq);
177
178 DPRINTF(SerialLink, "Response queue size: %d outresp: %d\n",
179 transmitList.size(), outstandingResponses);
180
181 // if the request queue is full then there is no hope
182 if (masterPort.reqQueueFull()) {
183 DPRINTF(SerialLink, "Request queue full\n");
184 retryReq = true;
185 } else if ( !retryReq ) {
186 // look at the response queue if we expect to see a response
187 bool expects_response = pkt->needsResponse() &&
188 !pkt->cacheResponding();
189 if (expects_response) {
190 if (respQueueFull()) {
191 DPRINTF(SerialLink, "Response queue full\n");
192 retryReq = true;
193 } else {
194 // ok to send the request with space for the response
195 DPRINTF(SerialLink, "Reserving space for response\n");
196 assert(outstandingResponses != respQueueLimit);
197 ++outstandingResponses;
198
199 // no need to set retryReq to false as this is already the
200 // case
201 }
202 }
203
204 if (!retryReq) {
205 // @todo: We need to pay for this and not just zero it out
206 pkt->headerDelay = pkt->payloadDelay = 0;
207
208 // We assume that the serializer component at the transmitter side
209 // does not need to receive the whole packet to start the
210 // serialization (this assumption is consistent with the HMC
211 // standard). But the deserializer waits for the complete packet
212 // to check its integrity first. So everytime a packet crosses a
213 // serial link, we should account for its deserialization latency
214 // only.
215 Cycles cycles = delay;
216 cycles += Cycles(divCeil(pkt->getSize() * 8,
217 serial_link.num_lanes));
218 Tick t = serial_link.clockEdge(cycles);
219
220 //@todo: If the processor sends two uncached requests towards HMC
221 // and the second one is smaller than the first one. It may happen
222 // that the second one crosses this link faster than the first one
223 // (because the packet waits in the link based on its size).
224 // This can reorder the received response.
225 masterPort.schedTimingReq(pkt, t);
226 }
227 }
228
229 // remember that we are now stalling a packet and that we have to
230 // tell the sending master to retry once space becomes available,
231 // we make no distinction whether the stalling is due to the
232 // request queue or response queue being full
233 return !retryReq;
234}
235
236void
237SerialLink::SerialLinkSlavePort::retryStalledReq()
238{
239 if (retryReq) {
240 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
241 retryReq = false;
242 sendRetryReq();
243 }
244}
245
246void
247SerialLink::SerialLinkMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
248{
249 // If we're about to put this packet at the head of the queue, we
250 // need to schedule an event to do the transmit. Otherwise there
251 // should already be an event scheduled for sending the head
252 // packet.
253 if (transmitList.empty()) {
254 serial_link.schedule(sendEvent, when);
255 }
256
257 assert(transmitList.size() != reqQueueLimit);
258
259 transmitList.emplace_back(DeferredPacket(pkt, when));
260}
261
262
263void
264SerialLink::SerialLinkSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
265{
266 // If we're about to put this packet at the head of the queue, we
267 // need to schedule an event to do the transmit. Otherwise there
268 // should already be an event scheduled for sending the head
269 // packet.
270 if (transmitList.empty()) {
271 serial_link.schedule(sendEvent, when);
272 }
273
274 transmitList.emplace_back(DeferredPacket(pkt, when));
275}
276
277void
278SerialLink::SerialLinkMasterPort::trySendTiming()
279{
280 assert(!transmitList.empty());
281
282 DeferredPacket req = transmitList.front();
283
284 assert(req.tick <= curTick());
285
286 PacketPtr pkt = req.pkt;
287
288 DPRINTF(SerialLink, "trySend request addr 0x%x, queue size %d\n",
289 pkt->getAddr(), transmitList.size());
290
291 if (sendTimingReq(pkt)) {
292 // send successful
293 transmitList.pop_front();
294
295 DPRINTF(SerialLink, "trySend request successful\n");
296
297 // If there are more packets to send, schedule event to try again.
298 if (!transmitList.empty()) {
299 DeferredPacket next_req = transmitList.front();
300 DPRINTF(SerialLink, "Scheduling next send\n");
301
302 // Make sure bandwidth limitation is met
303 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
304 serial_link.num_lanes));
305 Tick t = serial_link.clockEdge(cycles);
306 serial_link.schedule(sendEvent, std::max(next_req.tick, t));
307 }
308
309 // if we have stalled a request due to a full request queue,
310 // then send a retry at this point, also note that if the
311 // request we stalled was waiting for the response queue
312 // rather than the request queue we might stall it again
313 slavePort.retryStalledReq();
314 }
315
316 // if the send failed, then we try again once we receive a retry,
317 // and therefore there is no need to take any action
318}
319
320void
321SerialLink::SerialLinkSlavePort::trySendTiming()
322{
323 assert(!transmitList.empty());
324
325 DeferredPacket resp = transmitList.front();
326
327 assert(resp.tick <= curTick());
328
329 PacketPtr pkt = resp.pkt;
330
331 DPRINTF(SerialLink, "trySend response addr 0x%x, outstanding %d\n",
332 pkt->getAddr(), outstandingResponses);
333
334 if (sendTimingResp(pkt)) {
335 // send successful
336 transmitList.pop_front();
337 DPRINTF(SerialLink, "trySend response successful\n");
338
339 assert(outstandingResponses != 0);
340 --outstandingResponses;
341
342 // If there are more packets to send, schedule event to try again.
343 if (!transmitList.empty()) {
344 DeferredPacket next_resp = transmitList.front();
345 DPRINTF(SerialLink, "Scheduling next send\n");
346
347 // Make sure bandwidth limitation is met
348 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
349 serial_link.num_lanes));
350 Tick t = serial_link.clockEdge(cycles);
351 serial_link.schedule(sendEvent, std::max(next_resp.tick, t));
352 }
353
354 // if there is space in the request queue and we were stalling
355 // a request, it will definitely be possible to accept it now
356 // since there is guaranteed space in the response queue
357 if (!masterPort.reqQueueFull() && retryReq) {
358 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
359 retryReq = false;
360 sendRetryReq();
361 }
362 }
363
364 // if the send failed, then we try again once we receive a retry,
365 // and therefore there is no need to take any action
366}
367
368void
369SerialLink::SerialLinkMasterPort::recvReqRetry()
370{
371 trySendTiming();
372}
373
374void
375SerialLink::SerialLinkSlavePort::recvRespRetry()
376{
377 trySendTiming();
378}
379
380Tick
381SerialLink::SerialLinkSlavePort::recvAtomic(PacketPtr pkt)
382{
383 return delay * serial_link.clockPeriod() + masterPort.sendAtomic(pkt);
384}
385
386void
387SerialLink::SerialLinkSlavePort::recvFunctional(PacketPtr pkt)
388{
389 pkt->pushLabel(name());
390
391 // check the response queue
392 for (auto i = transmitList.begin(); i != transmitList.end(); ++i) {
393 if (pkt->checkFunctional((*i).pkt)) {
394 pkt->makeResponse();
395 return;
396 }
397 }
398
399 // also check the master port's request queue
400 if (masterPort.checkFunctional(pkt)) {
401 return;
402 }
403
404 pkt->popLabel();
405
406 // fall through if pkt still not satisfied
407 masterPort.sendFunctional(pkt);
408}
409
410bool
411SerialLink::SerialLinkMasterPort::checkFunctional(PacketPtr pkt)
412{
413 bool found = false;
414 auto i = transmitList.begin();
415
| 1/*
2 * Copyright (c) 2011-2013 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 * Copyright (c) 2015 The University of Bologna
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Ali Saidi
42 * Steve Reinhardt
43 * Andreas Hansson
44 * Erfan Azarkhish
45 */
46
47/**
48 * @file
49 * Implementation of the SerialLink Class, modeling Hybrid-Memory-Cube's
50 * serial interface.
51 */
52
53#include "mem/serial_link.hh"
54
55#include "base/trace.hh"
56#include "debug/SerialLink.hh"
57#include "params/SerialLink.hh"
58
59
60SerialLink::SerialLinkSlavePort::SerialLinkSlavePort(const std::string& _name,
61 SerialLink& _serial_link,
62 SerialLinkMasterPort& _masterPort,
63 Cycles _delay, int _resp_limit,
64 const std::vector<AddrRange>&
65 _ranges)
66 : SlavePort(_name, &_serial_link), serial_link(_serial_link),
67 masterPort(_masterPort), delay(_delay),
68 ranges(_ranges.begin(), _ranges.end()),
69 outstandingResponses(0), retryReq(false),
70 respQueueLimit(_resp_limit), sendEvent(*this)
71{
72}
73
74SerialLink::SerialLinkMasterPort::SerialLinkMasterPort(const std::string&
75 _name, SerialLink& _serial_link,
76 SerialLinkSlavePort& _slavePort,
77 Cycles _delay, int _req_limit)
78 : MasterPort(_name, &_serial_link), serial_link(_serial_link),
79 slavePort(_slavePort), delay(_delay), reqQueueLimit(_req_limit),
80 sendEvent(*this)
81{
82}
83
84SerialLink::SerialLink(SerialLinkParams *p)
85 : MemObject(p),
86 slavePort(p->name + ".slave", *this, masterPort,
87 ticksToCycles(p->delay), p->resp_size, p->ranges),
88 masterPort(p->name + ".master", *this, slavePort,
89 ticksToCycles(p->delay), p->req_size),
90 num_lanes(p->num_lanes)
91{
92}
93
94BaseMasterPort&
95SerialLink::getMasterPort(const std::string &if_name, PortID idx)
96{
97 if (if_name == "master")
98 return masterPort;
99 else
100 // pass it along to our super class
101 return MemObject::getMasterPort(if_name, idx);
102}
103
104BaseSlavePort&
105SerialLink::getSlavePort(const std::string &if_name, PortID idx)
106{
107 if (if_name == "slave")
108 return slavePort;
109 else
110 // pass it along to our super class
111 return MemObject::getSlavePort(if_name, idx);
112}
113
114void
115SerialLink::init()
116{
117 // make sure both sides are connected and have the same block size
118 if (!slavePort.isConnected() || !masterPort.isConnected())
119 fatal("Both ports of a serial_link must be connected.\n");
120
121 // notify the master side of our address ranges
122 slavePort.sendRangeChange();
123}
124
125bool
126SerialLink::SerialLinkSlavePort::respQueueFull() const
127{
128 return outstandingResponses == respQueueLimit;
129}
130
131bool
132SerialLink::SerialLinkMasterPort::reqQueueFull() const
133{
134 return transmitList.size() == reqQueueLimit;
135}
136
137bool
138SerialLink::SerialLinkMasterPort::recvTimingResp(PacketPtr pkt)
139{
140 // all checks are done when the request is accepted on the slave
141 // side, so we are guaranteed to have space for the response
142 DPRINTF(SerialLink, "recvTimingResp: %s addr 0x%x\n",
143 pkt->cmdString(), pkt->getAddr());
144
145 DPRINTF(SerialLink, "Request queue size: %d\n", transmitList.size());
146
147 // @todo: We need to pay for this and not just zero it out
148 pkt->headerDelay = pkt->payloadDelay = 0;
149
150 // This is similar to what happens for the request packets:
151 // The serializer will start serialization as soon as it receives the
152 // first flit, but the deserializer (at the host side in this case), will
153 // have to wait to receive the whole packet. So we only account for the
154 // deserialization latency.
155 Cycles cycles = delay;
156 cycles += Cycles(divCeil(pkt->getSize() * 8, serial_link.num_lanes));
157 Tick t = serial_link.clockEdge(cycles);
158
159 //@todo: If the processor sends two uncached requests towards HMC and the
160 // second one is smaller than the first one. It may happen that the second
161 // one crosses this link faster than the first one (because the packet
162 // waits in the link based on its size). This can reorder the received
163 // response.
164 slavePort.schedTimingResp(pkt, t);
165
166 return true;
167}
168
169bool
170SerialLink::SerialLinkSlavePort::recvTimingReq(PacketPtr pkt)
171{
172 DPRINTF(SerialLink, "recvTimingReq: %s addr 0x%x\n",
173 pkt->cmdString(), pkt->getAddr());
174
175 // we should not see a timing request if we are already in a retry
176 assert(!retryReq);
177
178 DPRINTF(SerialLink, "Response queue size: %d outresp: %d\n",
179 transmitList.size(), outstandingResponses);
180
181 // if the request queue is full then there is no hope
182 if (masterPort.reqQueueFull()) {
183 DPRINTF(SerialLink, "Request queue full\n");
184 retryReq = true;
185 } else if ( !retryReq ) {
186 // look at the response queue if we expect to see a response
187 bool expects_response = pkt->needsResponse() &&
188 !pkt->cacheResponding();
189 if (expects_response) {
190 if (respQueueFull()) {
191 DPRINTF(SerialLink, "Response queue full\n");
192 retryReq = true;
193 } else {
194 // ok to send the request with space for the response
195 DPRINTF(SerialLink, "Reserving space for response\n");
196 assert(outstandingResponses != respQueueLimit);
197 ++outstandingResponses;
198
199 // no need to set retryReq to false as this is already the
200 // case
201 }
202 }
203
204 if (!retryReq) {
205 // @todo: We need to pay for this and not just zero it out
206 pkt->headerDelay = pkt->payloadDelay = 0;
207
208 // We assume that the serializer component at the transmitter side
209 // does not need to receive the whole packet to start the
210 // serialization (this assumption is consistent with the HMC
211 // standard). But the deserializer waits for the complete packet
212 // to check its integrity first. So everytime a packet crosses a
213 // serial link, we should account for its deserialization latency
214 // only.
215 Cycles cycles = delay;
216 cycles += Cycles(divCeil(pkt->getSize() * 8,
217 serial_link.num_lanes));
218 Tick t = serial_link.clockEdge(cycles);
219
220 //@todo: If the processor sends two uncached requests towards HMC
221 // and the second one is smaller than the first one. It may happen
222 // that the second one crosses this link faster than the first one
223 // (because the packet waits in the link based on its size).
224 // This can reorder the received response.
225 masterPort.schedTimingReq(pkt, t);
226 }
227 }
228
229 // remember that we are now stalling a packet and that we have to
230 // tell the sending master to retry once space becomes available,
231 // we make no distinction whether the stalling is due to the
232 // request queue or response queue being full
233 return !retryReq;
234}
235
236void
237SerialLink::SerialLinkSlavePort::retryStalledReq()
238{
239 if (retryReq) {
240 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
241 retryReq = false;
242 sendRetryReq();
243 }
244}
245
246void
247SerialLink::SerialLinkMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
248{
249 // If we're about to put this packet at the head of the queue, we
250 // need to schedule an event to do the transmit. Otherwise there
251 // should already be an event scheduled for sending the head
252 // packet.
253 if (transmitList.empty()) {
254 serial_link.schedule(sendEvent, when);
255 }
256
257 assert(transmitList.size() != reqQueueLimit);
258
259 transmitList.emplace_back(DeferredPacket(pkt, when));
260}
261
262
263void
264SerialLink::SerialLinkSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
265{
266 // If we're about to put this packet at the head of the queue, we
267 // need to schedule an event to do the transmit. Otherwise there
268 // should already be an event scheduled for sending the head
269 // packet.
270 if (transmitList.empty()) {
271 serial_link.schedule(sendEvent, when);
272 }
273
274 transmitList.emplace_back(DeferredPacket(pkt, when));
275}
276
277void
278SerialLink::SerialLinkMasterPort::trySendTiming()
279{
280 assert(!transmitList.empty());
281
282 DeferredPacket req = transmitList.front();
283
284 assert(req.tick <= curTick());
285
286 PacketPtr pkt = req.pkt;
287
288 DPRINTF(SerialLink, "trySend request addr 0x%x, queue size %d\n",
289 pkt->getAddr(), transmitList.size());
290
291 if (sendTimingReq(pkt)) {
292 // send successful
293 transmitList.pop_front();
294
295 DPRINTF(SerialLink, "trySend request successful\n");
296
297 // If there are more packets to send, schedule event to try again.
298 if (!transmitList.empty()) {
299 DeferredPacket next_req = transmitList.front();
300 DPRINTF(SerialLink, "Scheduling next send\n");
301
302 // Make sure bandwidth limitation is met
303 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
304 serial_link.num_lanes));
305 Tick t = serial_link.clockEdge(cycles);
306 serial_link.schedule(sendEvent, std::max(next_req.tick, t));
307 }
308
309 // if we have stalled a request due to a full request queue,
310 // then send a retry at this point, also note that if the
311 // request we stalled was waiting for the response queue
312 // rather than the request queue we might stall it again
313 slavePort.retryStalledReq();
314 }
315
316 // if the send failed, then we try again once we receive a retry,
317 // and therefore there is no need to take any action
318}
319
320void
321SerialLink::SerialLinkSlavePort::trySendTiming()
322{
323 assert(!transmitList.empty());
324
325 DeferredPacket resp = transmitList.front();
326
327 assert(resp.tick <= curTick());
328
329 PacketPtr pkt = resp.pkt;
330
331 DPRINTF(SerialLink, "trySend response addr 0x%x, outstanding %d\n",
332 pkt->getAddr(), outstandingResponses);
333
334 if (sendTimingResp(pkt)) {
335 // send successful
336 transmitList.pop_front();
337 DPRINTF(SerialLink, "trySend response successful\n");
338
339 assert(outstandingResponses != 0);
340 --outstandingResponses;
341
342 // If there are more packets to send, schedule event to try again.
343 if (!transmitList.empty()) {
344 DeferredPacket next_resp = transmitList.front();
345 DPRINTF(SerialLink, "Scheduling next send\n");
346
347 // Make sure bandwidth limitation is met
348 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
349 serial_link.num_lanes));
350 Tick t = serial_link.clockEdge(cycles);
351 serial_link.schedule(sendEvent, std::max(next_resp.tick, t));
352 }
353
354 // if there is space in the request queue and we were stalling
355 // a request, it will definitely be possible to accept it now
356 // since there is guaranteed space in the response queue
357 if (!masterPort.reqQueueFull() && retryReq) {
358 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
359 retryReq = false;
360 sendRetryReq();
361 }
362 }
363
364 // if the send failed, then we try again once we receive a retry,
365 // and therefore there is no need to take any action
366}
367
368void
369SerialLink::SerialLinkMasterPort::recvReqRetry()
370{
371 trySendTiming();
372}
373
374void
375SerialLink::SerialLinkSlavePort::recvRespRetry()
376{
377 trySendTiming();
378}
379
380Tick
381SerialLink::SerialLinkSlavePort::recvAtomic(PacketPtr pkt)
382{
383 return delay * serial_link.clockPeriod() + masterPort.sendAtomic(pkt);
384}
385
386void
387SerialLink::SerialLinkSlavePort::recvFunctional(PacketPtr pkt)
388{
389 pkt->pushLabel(name());
390
391 // check the response queue
392 for (auto i = transmitList.begin(); i != transmitList.end(); ++i) {
393 if (pkt->checkFunctional((*i).pkt)) {
394 pkt->makeResponse();
395 return;
396 }
397 }
398
399 // also check the master port's request queue
400 if (masterPort.checkFunctional(pkt)) {
401 return;
402 }
403
404 pkt->popLabel();
405
406 // fall through if pkt still not satisfied
407 masterPort.sendFunctional(pkt);
408}
409
410bool
411SerialLink::SerialLinkMasterPort::checkFunctional(PacketPtr pkt)
412{
413 bool found = false;
414 auto i = transmitList.begin();
415
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