2 * Copyright (c) 2011-2013, 2015 ARM Limited
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.
14 * Copyright (c) 2006 The Regents of The University of Michigan
15 * All rights reserved.
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.
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.
47 * Implementation of a memory-mapped bridge that connects a master
48 * and a slave through a request and response queue.
51 #include "base/trace.hh"
52 #include "debug/Bridge.hh"
53 #include "mem/bridge.hh"
54 #include "params/Bridge.hh"
56 Bridge::BridgeSlavePort::BridgeSlavePort(const std::string
& _name
,
58 BridgeMasterPort
& _masterPort
,
59 Cycles _delay
, int _resp_limit
,
60 std::vector
<AddrRange
> _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)
68 Bridge::BridgeMasterPort::BridgeMasterPort(const std::string
& _name
,
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)
77 Bridge::Bridge(Params
*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
)
87 Bridge::getMasterPort(const std::string
&if_name
, PortID idx
)
89 if (if_name
== "master")
92 // pass it along to our super class
93 return MemObject::getMasterPort(if_name
, idx
);
97 Bridge::getSlavePort(const std::string
&if_name
, PortID idx
)
99 if (if_name
== "slave")
102 // pass it along to our super class
103 return MemObject::getSlavePort(if_name
, idx
);
109 // make sure both sides are connected and have the same block size
110 if (!slavePort
.isConnected() || !masterPort
.isConnected())
111 fatal("Both ports of a bridge must be connected.\n");
113 // notify the master side of our address ranges
114 slavePort
.sendRangeChange();
118 Bridge::BridgeSlavePort::respQueueFull() const
120 return outstandingResponses
== respQueueLimit
;
124 Bridge::BridgeMasterPort::reqQueueFull() const
126 return transmitList
.size() == reqQueueLimit
;
130 Bridge::BridgeMasterPort::recvTimingResp(PacketPtr pkt
)
132 // all checks are done when the request is accepted on the slave
133 // side, so we are guaranteed to have space for the response
134 DPRINTF(Bridge
, "recvTimingResp: %s addr 0x%x\n",
135 pkt
->cmdString(), pkt
->getAddr());
137 DPRINTF(Bridge
, "Request queue size: %d\n", transmitList
.size());
139 // technically the packet only reaches us after the header delay,
140 // and typically we also need to deserialise any payload (unless
141 // the two sides of the bridge are synchronous)
142 Tick receive_delay
= pkt
->headerDelay
+ pkt
->payloadDelay
;
143 pkt
->headerDelay
= pkt
->payloadDelay
= 0;
145 slavePort
.schedTimingResp(pkt
, bridge
.clockEdge(delay
) +
152 Bridge::BridgeSlavePort::recvTimingReq(PacketPtr pkt
)
154 DPRINTF(Bridge
, "recvTimingReq: %s addr 0x%x\n",
155 pkt
->cmdString(), pkt
->getAddr());
157 panic_if(pkt
->cacheResponding(), "Should not see packets where cache "
160 // we should not get a new request after committing to retry the
161 // current one, but unfortunately the CPU violates this rule, so
162 // simply ignore it for now
166 DPRINTF(Bridge
, "Response queue size: %d outresp: %d\n",
167 transmitList
.size(), outstandingResponses
);
169 // if the request queue is full then there is no hope
170 if (masterPort
.reqQueueFull()) {
171 DPRINTF(Bridge
, "Request queue full\n");
174 // look at the response queue if we expect to see a response
175 bool expects_response
= pkt
->needsResponse();
176 if (expects_response
) {
177 if (respQueueFull()) {
178 DPRINTF(Bridge
, "Response queue full\n");
181 // ok to send the request with space for the response
182 DPRINTF(Bridge
, "Reserving space for response\n");
183 assert(outstandingResponses
!= respQueueLimit
);
184 ++outstandingResponses
;
186 // no need to set retryReq to false as this is already the
192 // technically the packet only reaches us after the header
193 // delay, and typically we also need to deserialise any
194 // payload (unless the two sides of the bridge are
196 Tick receive_delay
= pkt
->headerDelay
+ pkt
->payloadDelay
;
197 pkt
->headerDelay
= pkt
->payloadDelay
= 0;
199 masterPort
.schedTimingReq(pkt
, bridge
.clockEdge(delay
) +
204 // remember that we are now stalling a packet and that we have to
205 // tell the sending master to retry once space becomes available,
206 // we make no distinction whether the stalling is due to the
207 // request queue or response queue being full
212 Bridge::BridgeSlavePort::retryStalledReq()
215 DPRINTF(Bridge
, "Request waiting for retry, now retrying\n");
222 Bridge::BridgeMasterPort::schedTimingReq(PacketPtr pkt
, Tick when
)
224 // If we're about to put this packet at the head of the queue, we
225 // need to schedule an event to do the transmit. Otherwise there
226 // should already be an event scheduled for sending the head
228 if (transmitList
.empty()) {
229 bridge
.schedule(sendEvent
, when
);
232 assert(transmitList
.size() != reqQueueLimit
);
234 transmitList
.emplace_back(pkt
, when
);
239 Bridge::BridgeSlavePort::schedTimingResp(PacketPtr pkt
, Tick when
)
241 // If we're about to put this packet at the head of the queue, we
242 // need to schedule an event to do the transmit. Otherwise there
243 // should already be an event scheduled for sending the head
245 if (transmitList
.empty()) {
246 bridge
.schedule(sendEvent
, when
);
249 transmitList
.emplace_back(pkt
, when
);
253 Bridge::BridgeMasterPort::trySendTiming()
255 assert(!transmitList
.empty());
257 DeferredPacket req
= transmitList
.front();
259 assert(req
.tick
<= curTick());
261 PacketPtr pkt
= req
.pkt
;
263 DPRINTF(Bridge
, "trySend request addr 0x%x, queue size %d\n",
264 pkt
->getAddr(), transmitList
.size());
266 if (sendTimingReq(pkt
)) {
268 transmitList
.pop_front();
269 DPRINTF(Bridge
, "trySend request successful\n");
271 // If there are more packets to send, schedule event to try again.
272 if (!transmitList
.empty()) {
273 DeferredPacket next_req
= transmitList
.front();
274 DPRINTF(Bridge
, "Scheduling next send\n");
275 bridge
.schedule(sendEvent
, std::max(next_req
.tick
,
276 bridge
.clockEdge()));
279 // if we have stalled a request due to a full request queue,
280 // then send a retry at this point, also note that if the
281 // request we stalled was waiting for the response queue
282 // rather than the request queue we might stall it again
283 slavePort
.retryStalledReq();
286 // if the send failed, then we try again once we receive a retry,
287 // and therefore there is no need to take any action
291 Bridge::BridgeSlavePort::trySendTiming()
293 assert(!transmitList
.empty());
295 DeferredPacket resp
= transmitList
.front();
297 assert(resp
.tick
<= curTick());
299 PacketPtr pkt
= resp
.pkt
;
301 DPRINTF(Bridge
, "trySend response addr 0x%x, outstanding %d\n",
302 pkt
->getAddr(), outstandingResponses
);
304 if (sendTimingResp(pkt
)) {
306 transmitList
.pop_front();
307 DPRINTF(Bridge
, "trySend response successful\n");
309 assert(outstandingResponses
!= 0);
310 --outstandingResponses
;
312 // If there are more packets to send, schedule event to try again.
313 if (!transmitList
.empty()) {
314 DeferredPacket next_resp
= transmitList
.front();
315 DPRINTF(Bridge
, "Scheduling next send\n");
316 bridge
.schedule(sendEvent
, std::max(next_resp
.tick
,
317 bridge
.clockEdge()));
320 // if there is space in the request queue and we were stalling
321 // a request, it will definitely be possible to accept it now
322 // since there is guaranteed space in the response queue
323 if (!masterPort
.reqQueueFull() && retryReq
) {
324 DPRINTF(Bridge
, "Request waiting for retry, now retrying\n");
330 // if the send failed, then we try again once we receive a retry,
331 // and therefore there is no need to take any action
335 Bridge::BridgeMasterPort::recvReqRetry()
341 Bridge::BridgeSlavePort::recvRespRetry()
347 Bridge::BridgeSlavePort::recvAtomic(PacketPtr pkt
)
349 panic_if(pkt
->cacheResponding(), "Should not see packets where cache "
352 return delay
* bridge
.clockPeriod() + masterPort
.sendAtomic(pkt
);
356 Bridge::BridgeSlavePort::recvFunctional(PacketPtr pkt
)
358 pkt
->pushLabel(name());
360 // check the response queue
361 for (auto i
= transmitList
.begin(); i
!= transmitList
.end(); ++i
) {
362 if (pkt
->checkFunctional((*i
).pkt
)) {
368 // also check the master port's request queue
369 if (masterPort
.checkFunctional(pkt
)) {
375 // fall through if pkt still not satisfied
376 masterPort
.sendFunctional(pkt
);
380 Bridge::BridgeMasterPort::checkFunctional(PacketPtr pkt
)
383 auto i
= transmitList
.begin();
385 while (i
!= transmitList
.end() && !found
) {
386 if (pkt
->checkFunctional((*i
).pkt
)) {
397 Bridge::BridgeSlavePort::getAddrRanges() const
403 BridgeParams::create()
405 return new Bridge(this);