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
59SerialLink::SerialLinkSlavePort::SerialLinkSlavePort(const std::string& _name,
60 SerialLink& _serial_link,
61 SerialLinkMasterPort& _masterPort,
62 Cycles _delay, int _resp_limit,
63 const std::vector<AddrRange>&
64 _ranges)
65 : SlavePort(_name, &_serial_link), serial_link(_serial_link),
66 masterPort(_masterPort), delay(_delay),
67 ranges(_ranges.begin(), _ranges.end()),
68 outstandingResponses(0), retryReq(false),
69 respQueueLimit(_resp_limit),
70 sendEvent([this]{ trySendTiming(); }, _name)
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]{ trySendTiming(); }, _name)
81{
82}
83
84SerialLink::SerialLink(SerialLinkParams *p)
| 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
59SerialLink::SerialLinkSlavePort::SerialLinkSlavePort(const std::string& _name,
60 SerialLink& _serial_link,
61 SerialLinkMasterPort& _masterPort,
62 Cycles _delay, int _resp_limit,
63 const std::vector<AddrRange>&
64 _ranges)
65 : SlavePort(_name, &_serial_link), serial_link(_serial_link),
66 masterPort(_masterPort), delay(_delay),
67 ranges(_ranges.begin(), _ranges.end()),
68 outstandingResponses(0), retryReq(false),
69 respQueueLimit(_resp_limit),
70 sendEvent([this]{ trySendTiming(); }, _name)
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]{ trySendTiming(); }, _name)
81{
82}
83
84SerialLink::SerialLink(SerialLinkParams *p)
|
85 : MemObject(p),
| 85 : ClockedObject(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 link_speed(p->link_speed)
92
93{
94}
95
96Port&
97SerialLink::getPort(const std::string &if_name, PortID idx)
98{
99 if (if_name == "master")
100 return masterPort;
101 else if (if_name == "slave")
102 return slavePort;
103 else
104 // pass it along to our super class
| 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 link_speed(p->link_speed)
92
93{
94}
95
96Port&
97SerialLink::getPort(const std::string &if_name, PortID idx)
98{
99 if (if_name == "master")
100 return masterPort;
101 else if (if_name == "slave")
102 return slavePort;
103 else
104 // pass it along to our super class
|
105 return MemObject::getPort(if_name, idx);
| 105 return ClockedObject::getPort(if_name, idx);
|
106}
107
108void
109SerialLink::init()
110{
111 // make sure both sides are connected and have the same block size
112 if (!slavePort.isConnected() || !masterPort.isConnected())
113 fatal("Both ports of a serial_link must be connected.\n");
114
115 // notify the master side of our address ranges
116 slavePort.sendRangeChange();
117}
118
119bool
120SerialLink::SerialLinkSlavePort::respQueueFull() const
121{
122 return outstandingResponses == respQueueLimit;
123}
124
125bool
126SerialLink::SerialLinkMasterPort::reqQueueFull() const
127{
128 return transmitList.size() == reqQueueLimit;
129}
130
131bool
132SerialLink::SerialLinkMasterPort::recvTimingResp(PacketPtr pkt)
133{
134 // all checks are done when the request is accepted on the slave
135 // side, so we are guaranteed to have space for the response
136 DPRINTF(SerialLink, "recvTimingResp: %s addr 0x%x\n",
137 pkt->cmdString(), pkt->getAddr());
138
139 DPRINTF(SerialLink, "Request queue size: %d\n", transmitList.size());
140
141 // @todo: We need to pay for this and not just zero it out
142 pkt->headerDelay = pkt->payloadDelay = 0;
143
144 // This is similar to what happens for the request packets:
145 // The serializer will start serialization as soon as it receives the
146 // first flit, but the deserializer (at the host side in this case), will
147 // have to wait to receive the whole packet. So we only account for the
148 // deserialization latency.
149 Cycles cycles = delay;
150 cycles += Cycles(divCeil(pkt->getSize() * 8, serial_link.num_lanes
151 * serial_link.link_speed));
152 Tick t = serial_link.clockEdge(cycles);
153
154 //@todo: If the processor sends two uncached requests towards HMC and the
155 // second one is smaller than the first one. It may happen that the second
156 // one crosses this link faster than the first one (because the packet
157 // waits in the link based on its size). This can reorder the received
158 // response.
159 slavePort.schedTimingResp(pkt, t);
160
161 return true;
162}
163
164bool
165SerialLink::SerialLinkSlavePort::recvTimingReq(PacketPtr pkt)
166{
167 DPRINTF(SerialLink, "recvTimingReq: %s addr 0x%x\n",
168 pkt->cmdString(), pkt->getAddr());
169
170 // we should not see a timing request if we are already in a retry
171 assert(!retryReq);
172
173 DPRINTF(SerialLink, "Response queue size: %d outresp: %d\n",
174 transmitList.size(), outstandingResponses);
175
176 // if the request queue is full then there is no hope
177 if (masterPort.reqQueueFull()) {
178 DPRINTF(SerialLink, "Request queue full\n");
179 retryReq = true;
180 } else if ( !retryReq ) {
181 // look at the response queue if we expect to see a response
182 bool expects_response = pkt->needsResponse() &&
183 !pkt->cacheResponding();
184 if (expects_response) {
185 if (respQueueFull()) {
186 DPRINTF(SerialLink, "Response queue full\n");
187 retryReq = true;
188 } else {
189 // ok to send the request with space for the response
190 DPRINTF(SerialLink, "Reserving space for response\n");
191 assert(outstandingResponses != respQueueLimit);
192 ++outstandingResponses;
193
194 // no need to set retryReq to false as this is already the
195 // case
196 }
197 }
198
199 if (!retryReq) {
200 // @todo: We need to pay for this and not just zero it out
201 pkt->headerDelay = pkt->payloadDelay = 0;
202
203 // We assume that the serializer component at the transmitter side
204 // does not need to receive the whole packet to start the
205 // serialization (this assumption is consistent with the HMC
206 // standard). But the deserializer waits for the complete packet
207 // to check its integrity first. So everytime a packet crosses a
208 // serial link, we should account for its deserialization latency
209 // only.
210 Cycles cycles = delay;
211 cycles += Cycles(divCeil(pkt->getSize() * 8,
212 serial_link.num_lanes * serial_link.link_speed));
213 Tick t = serial_link.clockEdge(cycles);
214
215 //@todo: If the processor sends two uncached requests towards HMC
216 // and the second one is smaller than the first one. It may happen
217 // that the second one crosses this link faster than the first one
218 // (because the packet waits in the link based on its size).
219 // This can reorder the received response.
220 masterPort.schedTimingReq(pkt, t);
221 }
222 }
223
224 // remember that we are now stalling a packet and that we have to
225 // tell the sending master to retry once space becomes available,
226 // we make no distinction whether the stalling is due to the
227 // request queue or response queue being full
228 return !retryReq;
229}
230
231void
232SerialLink::SerialLinkSlavePort::retryStalledReq()
233{
234 if (retryReq) {
235 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
236 retryReq = false;
237 sendRetryReq();
238 }
239}
240
241void
242SerialLink::SerialLinkMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
243{
244 // If we're about to put this packet at the head of the queue, we
245 // need to schedule an event to do the transmit. Otherwise there
246 // should already be an event scheduled for sending the head
247 // packet.
248 if (transmitList.empty()) {
249 serial_link.schedule(sendEvent, when);
250 }
251
252 assert(transmitList.size() != reqQueueLimit);
253
254 transmitList.emplace_back(DeferredPacket(pkt, when));
255}
256
257
258void
259SerialLink::SerialLinkSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
260{
261 // If we're about to put this packet at the head of the queue, we
262 // need to schedule an event to do the transmit. Otherwise there
263 // should already be an event scheduled for sending the head
264 // packet.
265 if (transmitList.empty()) {
266 serial_link.schedule(sendEvent, when);
267 }
268
269 transmitList.emplace_back(DeferredPacket(pkt, when));
270}
271
272void
273SerialLink::SerialLinkMasterPort::trySendTiming()
274{
275 assert(!transmitList.empty());
276
277 DeferredPacket req = transmitList.front();
278
279 assert(req.tick <= curTick());
280
281 PacketPtr pkt = req.pkt;
282
283 DPRINTF(SerialLink, "trySend request addr 0x%x, queue size %d\n",
284 pkt->getAddr(), transmitList.size());
285
286 if (sendTimingReq(pkt)) {
287 // send successful
288 transmitList.pop_front();
289
290 DPRINTF(SerialLink, "trySend request successful\n");
291
292 // If there are more packets to send, schedule event to try again.
293 if (!transmitList.empty()) {
294 DeferredPacket next_req = transmitList.front();
295 DPRINTF(SerialLink, "Scheduling next send\n");
296
297 // Make sure bandwidth limitation is met
298 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
299 serial_link.num_lanes * serial_link.link_speed));
300 Tick t = serial_link.clockEdge(cycles);
301 serial_link.schedule(sendEvent, std::max(next_req.tick, t));
302 }
303
304 // if we have stalled a request due to a full request queue,
305 // then send a retry at this point, also note that if the
306 // request we stalled was waiting for the response queue
307 // rather than the request queue we might stall it again
308 slavePort.retryStalledReq();
309 }
310
311 // if the send failed, then we try again once we receive a retry,
312 // and therefore there is no need to take any action
313}
314
315void
316SerialLink::SerialLinkSlavePort::trySendTiming()
317{
318 assert(!transmitList.empty());
319
320 DeferredPacket resp = transmitList.front();
321
322 assert(resp.tick <= curTick());
323
324 PacketPtr pkt = resp.pkt;
325
326 DPRINTF(SerialLink, "trySend response addr 0x%x, outstanding %d\n",
327 pkt->getAddr(), outstandingResponses);
328
329 if (sendTimingResp(pkt)) {
330 // send successful
331 transmitList.pop_front();
332 DPRINTF(SerialLink, "trySend response successful\n");
333
334 assert(outstandingResponses != 0);
335 --outstandingResponses;
336
337 // If there are more packets to send, schedule event to try again.
338 if (!transmitList.empty()) {
339 DeferredPacket next_resp = transmitList.front();
340 DPRINTF(SerialLink, "Scheduling next send\n");
341
342 // Make sure bandwidth limitation is met
343 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
344 serial_link.num_lanes * serial_link.link_speed));
345 Tick t = serial_link.clockEdge(cycles);
346 serial_link.schedule(sendEvent, std::max(next_resp.tick, t));
347 }
348
349 // if there is space in the request queue and we were stalling
350 // a request, it will definitely be possible to accept it now
351 // since there is guaranteed space in the response queue
352 if (!masterPort.reqQueueFull() && retryReq) {
353 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
354 retryReq = false;
355 sendRetryReq();
356 }
357 }
358
359 // if the send failed, then we try again once we receive a retry,
360 // and therefore there is no need to take any action
361}
362
363void
364SerialLink::SerialLinkMasterPort::recvReqRetry()
365{
366 trySendTiming();
367}
368
369void
370SerialLink::SerialLinkSlavePort::recvRespRetry()
371{
372 trySendTiming();
373}
374
375Tick
376SerialLink::SerialLinkSlavePort::recvAtomic(PacketPtr pkt)
377{
378 return delay * serial_link.clockPeriod() + masterPort.sendAtomic(pkt);
379}
380
381void
382SerialLink::SerialLinkSlavePort::recvFunctional(PacketPtr pkt)
383{
384 pkt->pushLabel(name());
385
386 // check the response queue
387 for (auto i = transmitList.begin(); i != transmitList.end(); ++i) {
388 if (pkt->trySatisfyFunctional((*i).pkt)) {
389 pkt->makeResponse();
390 return;
391 }
392 }
393
394 // also check the master port's request queue
395 if (masterPort.trySatisfyFunctional(pkt)) {
396 return;
397 }
398
399 pkt->popLabel();
400
401 // fall through if pkt still not satisfied
402 masterPort.sendFunctional(pkt);
403}
404
405bool
406SerialLink::SerialLinkMasterPort::trySatisfyFunctional(PacketPtr pkt)
407{
408 bool found = false;
409 auto i = transmitList.begin();
410
411 while (i != transmitList.end() && !found) {
412 if (pkt->trySatisfyFunctional((*i).pkt)) {
413 pkt->makeResponse();
414 found = true;
415 }
416 ++i;
417 }
418
419 return found;
420}
421
422AddrRangeList
423SerialLink::SerialLinkSlavePort::getAddrRanges() const
424{
425 return ranges;
426}
427
428SerialLink *
429SerialLinkParams::create()
430{
431 return new SerialLink(this);
432}
| 106}
107
108void
109SerialLink::init()
110{
111 // make sure both sides are connected and have the same block size
112 if (!slavePort.isConnected() || !masterPort.isConnected())
113 fatal("Both ports of a serial_link must be connected.\n");
114
115 // notify the master side of our address ranges
116 slavePort.sendRangeChange();
117}
118
119bool
120SerialLink::SerialLinkSlavePort::respQueueFull() const
121{
122 return outstandingResponses == respQueueLimit;
123}
124
125bool
126SerialLink::SerialLinkMasterPort::reqQueueFull() const
127{
128 return transmitList.size() == reqQueueLimit;
129}
130
131bool
132SerialLink::SerialLinkMasterPort::recvTimingResp(PacketPtr pkt)
133{
134 // all checks are done when the request is accepted on the slave
135 // side, so we are guaranteed to have space for the response
136 DPRINTF(SerialLink, "recvTimingResp: %s addr 0x%x\n",
137 pkt->cmdString(), pkt->getAddr());
138
139 DPRINTF(SerialLink, "Request queue size: %d\n", transmitList.size());
140
141 // @todo: We need to pay for this and not just zero it out
142 pkt->headerDelay = pkt->payloadDelay = 0;
143
144 // This is similar to what happens for the request packets:
145 // The serializer will start serialization as soon as it receives the
146 // first flit, but the deserializer (at the host side in this case), will
147 // have to wait to receive the whole packet. So we only account for the
148 // deserialization latency.
149 Cycles cycles = delay;
150 cycles += Cycles(divCeil(pkt->getSize() * 8, serial_link.num_lanes
151 * serial_link.link_speed));
152 Tick t = serial_link.clockEdge(cycles);
153
154 //@todo: If the processor sends two uncached requests towards HMC and the
155 // second one is smaller than the first one. It may happen that the second
156 // one crosses this link faster than the first one (because the packet
157 // waits in the link based on its size). This can reorder the received
158 // response.
159 slavePort.schedTimingResp(pkt, t);
160
161 return true;
162}
163
164bool
165SerialLink::SerialLinkSlavePort::recvTimingReq(PacketPtr pkt)
166{
167 DPRINTF(SerialLink, "recvTimingReq: %s addr 0x%x\n",
168 pkt->cmdString(), pkt->getAddr());
169
170 // we should not see a timing request if we are already in a retry
171 assert(!retryReq);
172
173 DPRINTF(SerialLink, "Response queue size: %d outresp: %d\n",
174 transmitList.size(), outstandingResponses);
175
176 // if the request queue is full then there is no hope
177 if (masterPort.reqQueueFull()) {
178 DPRINTF(SerialLink, "Request queue full\n");
179 retryReq = true;
180 } else if ( !retryReq ) {
181 // look at the response queue if we expect to see a response
182 bool expects_response = pkt->needsResponse() &&
183 !pkt->cacheResponding();
184 if (expects_response) {
185 if (respQueueFull()) {
186 DPRINTF(SerialLink, "Response queue full\n");
187 retryReq = true;
188 } else {
189 // ok to send the request with space for the response
190 DPRINTF(SerialLink, "Reserving space for response\n");
191 assert(outstandingResponses != respQueueLimit);
192 ++outstandingResponses;
193
194 // no need to set retryReq to false as this is already the
195 // case
196 }
197 }
198
199 if (!retryReq) {
200 // @todo: We need to pay for this and not just zero it out
201 pkt->headerDelay = pkt->payloadDelay = 0;
202
203 // We assume that the serializer component at the transmitter side
204 // does not need to receive the whole packet to start the
205 // serialization (this assumption is consistent with the HMC
206 // standard). But the deserializer waits for the complete packet
207 // to check its integrity first. So everytime a packet crosses a
208 // serial link, we should account for its deserialization latency
209 // only.
210 Cycles cycles = delay;
211 cycles += Cycles(divCeil(pkt->getSize() * 8,
212 serial_link.num_lanes * serial_link.link_speed));
213 Tick t = serial_link.clockEdge(cycles);
214
215 //@todo: If the processor sends two uncached requests towards HMC
216 // and the second one is smaller than the first one. It may happen
217 // that the second one crosses this link faster than the first one
218 // (because the packet waits in the link based on its size).
219 // This can reorder the received response.
220 masterPort.schedTimingReq(pkt, t);
221 }
222 }
223
224 // remember that we are now stalling a packet and that we have to
225 // tell the sending master to retry once space becomes available,
226 // we make no distinction whether the stalling is due to the
227 // request queue or response queue being full
228 return !retryReq;
229}
230
231void
232SerialLink::SerialLinkSlavePort::retryStalledReq()
233{
234 if (retryReq) {
235 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
236 retryReq = false;
237 sendRetryReq();
238 }
239}
240
241void
242SerialLink::SerialLinkMasterPort::schedTimingReq(PacketPtr pkt, Tick when)
243{
244 // If we're about to put this packet at the head of the queue, we
245 // need to schedule an event to do the transmit. Otherwise there
246 // should already be an event scheduled for sending the head
247 // packet.
248 if (transmitList.empty()) {
249 serial_link.schedule(sendEvent, when);
250 }
251
252 assert(transmitList.size() != reqQueueLimit);
253
254 transmitList.emplace_back(DeferredPacket(pkt, when));
255}
256
257
258void
259SerialLink::SerialLinkSlavePort::schedTimingResp(PacketPtr pkt, Tick when)
260{
261 // If we're about to put this packet at the head of the queue, we
262 // need to schedule an event to do the transmit. Otherwise there
263 // should already be an event scheduled for sending the head
264 // packet.
265 if (transmitList.empty()) {
266 serial_link.schedule(sendEvent, when);
267 }
268
269 transmitList.emplace_back(DeferredPacket(pkt, when));
270}
271
272void
273SerialLink::SerialLinkMasterPort::trySendTiming()
274{
275 assert(!transmitList.empty());
276
277 DeferredPacket req = transmitList.front();
278
279 assert(req.tick <= curTick());
280
281 PacketPtr pkt = req.pkt;
282
283 DPRINTF(SerialLink, "trySend request addr 0x%x, queue size %d\n",
284 pkt->getAddr(), transmitList.size());
285
286 if (sendTimingReq(pkt)) {
287 // send successful
288 transmitList.pop_front();
289
290 DPRINTF(SerialLink, "trySend request successful\n");
291
292 // If there are more packets to send, schedule event to try again.
293 if (!transmitList.empty()) {
294 DeferredPacket next_req = transmitList.front();
295 DPRINTF(SerialLink, "Scheduling next send\n");
296
297 // Make sure bandwidth limitation is met
298 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
299 serial_link.num_lanes * serial_link.link_speed));
300 Tick t = serial_link.clockEdge(cycles);
301 serial_link.schedule(sendEvent, std::max(next_req.tick, t));
302 }
303
304 // if we have stalled a request due to a full request queue,
305 // then send a retry at this point, also note that if the
306 // request we stalled was waiting for the response queue
307 // rather than the request queue we might stall it again
308 slavePort.retryStalledReq();
309 }
310
311 // if the send failed, then we try again once we receive a retry,
312 // and therefore there is no need to take any action
313}
314
315void
316SerialLink::SerialLinkSlavePort::trySendTiming()
317{
318 assert(!transmitList.empty());
319
320 DeferredPacket resp = transmitList.front();
321
322 assert(resp.tick <= curTick());
323
324 PacketPtr pkt = resp.pkt;
325
326 DPRINTF(SerialLink, "trySend response addr 0x%x, outstanding %d\n",
327 pkt->getAddr(), outstandingResponses);
328
329 if (sendTimingResp(pkt)) {
330 // send successful
331 transmitList.pop_front();
332 DPRINTF(SerialLink, "trySend response successful\n");
333
334 assert(outstandingResponses != 0);
335 --outstandingResponses;
336
337 // If there are more packets to send, schedule event to try again.
338 if (!transmitList.empty()) {
339 DeferredPacket next_resp = transmitList.front();
340 DPRINTF(SerialLink, "Scheduling next send\n");
341
342 // Make sure bandwidth limitation is met
343 Cycles cycles = Cycles(divCeil(pkt->getSize() * 8,
344 serial_link.num_lanes * serial_link.link_speed));
345 Tick t = serial_link.clockEdge(cycles);
346 serial_link.schedule(sendEvent, std::max(next_resp.tick, t));
347 }
348
349 // if there is space in the request queue and we were stalling
350 // a request, it will definitely be possible to accept it now
351 // since there is guaranteed space in the response queue
352 if (!masterPort.reqQueueFull() && retryReq) {
353 DPRINTF(SerialLink, "Request waiting for retry, now retrying\n");
354 retryReq = false;
355 sendRetryReq();
356 }
357 }
358
359 // if the send failed, then we try again once we receive a retry,
360 // and therefore there is no need to take any action
361}
362
363void
364SerialLink::SerialLinkMasterPort::recvReqRetry()
365{
366 trySendTiming();
367}
368
369void
370SerialLink::SerialLinkSlavePort::recvRespRetry()
371{
372 trySendTiming();
373}
374
375Tick
376SerialLink::SerialLinkSlavePort::recvAtomic(PacketPtr pkt)
377{
378 return delay * serial_link.clockPeriod() + masterPort.sendAtomic(pkt);
379}
380
381void
382SerialLink::SerialLinkSlavePort::recvFunctional(PacketPtr pkt)
383{
384 pkt->pushLabel(name());
385
386 // check the response queue
387 for (auto i = transmitList.begin(); i != transmitList.end(); ++i) {
388 if (pkt->trySatisfyFunctional((*i).pkt)) {
389 pkt->makeResponse();
390 return;
391 }
392 }
393
394 // also check the master port's request queue
395 if (masterPort.trySatisfyFunctional(pkt)) {
396 return;
397 }
398
399 pkt->popLabel();
400
401 // fall through if pkt still not satisfied
402 masterPort.sendFunctional(pkt);
403}
404
405bool
406SerialLink::SerialLinkMasterPort::trySatisfyFunctional(PacketPtr pkt)
407{
408 bool found = false;
409 auto i = transmitList.begin();
410
411 while (i != transmitList.end() && !found) {
412 if (pkt->trySatisfyFunctional((*i).pkt)) {
413 pkt->makeResponse();
414 found = true;
415 }
416 ++i;
417 }
418
419 return found;
420}
421
422AddrRangeList
423SerialLink::SerialLinkSlavePort::getAddrRanges() const
424{
425 return ranges;
426}
427
428SerialLink *
429SerialLinkParams::create()
430{
431 return new SerialLink(this);
432}
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