1
2/*
3 * Copyright (c) 2006 The Regents of The University of Michigan
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Ali Saidi
30 * Steve Reinhardt
31 */
32
33/**
34 * @file
35 * Definition of a simple bus bridge without buffering.
36 */
37
38#include <algorithm>
39
40#include "base/trace.hh"
41#include "mem/bridge.hh"
42#include "sim/builder.hh"
43
44Bridge::BridgePort::BridgePort(const std::string &_name,
45 Bridge *_bridge, BridgePort *_otherPort,
46 int _delay, int _nack_delay, int _req_limit,
47 int _resp_limit, bool fix_partial_write)
48 : Port(_name), bridge(_bridge), otherPort(_otherPort),
49 delay(_delay), nackDelay(_nack_delay), fixPartialWrite(fix_partial_write),
50 outstandingResponses(0), queuedRequests(0), inRetry(false),
51 reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this)
52{
53}
54
55Bridge::Bridge(Params *p)
56 : MemObject(p->name),
57 portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay,
58 p->req_size_a, p->resp_size_a, p->fix_partial_write_a),
59 portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay,
60 p->req_size_b, p->resp_size_b, p->fix_partial_write_b),
61 ackWrites(p->write_ack), _params(p)
62{
63 if (ackWrites)
64 panic("No support for acknowledging writes\n");
65}
66
67Port *
68Bridge::getPort(const std::string &if_name, int idx)
69{
70 BridgePort *port;
71
72 if (if_name == "side_a")
73 port = &portA;
74 else if (if_name == "side_b")
75 port = &portB;
76 else
77 return NULL;
78
79 if (port->getPeer() != NULL)
80 panic("bridge side %s already connected to.", if_name);
81 return port;
82}
83
84
85void
86Bridge::init()
87{
88 // Make sure that both sides are connected to.
89 if (portA.getPeer() == NULL || portB.getPeer() == NULL)
90 fatal("Both ports of bus bridge are not connected to a bus.\n");
91
92 if (portA.peerBlockSize() != portB.peerBlockSize())
93 fatal("Busses don't have the same block size... Not supported.\n");
94}
95
96bool
97Bridge::BridgePort::respQueueFull()
98{
99 assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit);
100 return outstandingResponses >= respQueueLimit;
101}
102
103bool
104Bridge::BridgePort::reqQueueFull()
105{
106 assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit);
107 return queuedRequests >= reqQueueLimit;
108}
109
110/** Function called by the port when the bus is receiving a Timing
111 * transaction.*/
112bool
113Bridge::BridgePort::recvTiming(PacketPtr pkt)
114{
115 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
116 pkt->getSrc(), pkt->getDest(), pkt->getAddr());
117
118 DPRINTF(BusBridge, "Local queue size: %d outreq: %d outresp: %d\n",
119 sendQueue.size(), queuedRequests, outstandingResponses);
120 DPRINTF(BusBridge, "Remove queue size: %d outreq: %d outresp: %d\n",
121 otherPort->sendQueue.size(), otherPort->queuedRequests,
122 otherPort->outstandingResponses);
123
124 if (pkt->isRequest() && otherPort->reqQueueFull() && !pkt->wasNacked()) {
125 DPRINTF(BusBridge, "Remote queue full, nacking\n");
126 nackRequest(pkt);
127 return true;
128 }
129
130 if (pkt->needsResponse() && !pkt->wasNacked())
131 if (respQueueFull()) {
132 DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n");
133 DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n",
134 sendQueue.size(), queuedRequests, outstandingResponses);
135 nackRequest(pkt);
136 return true;
137 } else {
138 DPRINTF(BusBridge, "Request Needs response, reserving space\n");
139 ++outstandingResponses;
140 }
141
142 otherPort->queueForSendTiming(pkt);
143
144 return true;
145}
146
147void
148Bridge::BridgePort::nackRequest(PacketPtr pkt)
149{
150 // Nack the packet
151 pkt->setNacked();
152 pkt->setDest(pkt->getSrc());
153
154 //put it on the list to send
155 Tick readyTime = curTick + nackDelay;
156 PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true);
157
158 // nothing on the list, add it and we're done
159 if (sendQueue.empty()) {
160 assert(!sendEvent.scheduled());
161 sendEvent.schedule(readyTime);
162 sendQueue.push_back(buf);
163 return;
164 }
165
166 assert(sendEvent.scheduled() || inRetry);
167
168 // does it go at the end?
169 if (readyTime >= sendQueue.back()->ready) {
170 sendQueue.push_back(buf);
171 return;
172 }
173
174 // ok, somewhere in the middle, fun
175 std::list<PacketBuffer*>::iterator i = sendQueue.begin();
176 std::list<PacketBuffer*>::iterator end = sendQueue.end();
177 std::list<PacketBuffer*>::iterator begin = sendQueue.begin();
178 bool done = false;
179
180 while (i != end && !done) {
181 if (readyTime < (*i)->ready) {
182 if (i == begin)
183 sendEvent.reschedule(readyTime);
184 sendQueue.insert(i,buf);
185 done = true;
186 }
187 i++;
188 }
189 assert(done);
190}
191
192
193void
194Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
195{
196 if (pkt->isResponse() || pkt->wasNacked()) {
197 // This is a response for a request we forwarded earlier. The
198 // corresponding PacketBuffer should be stored in the packet's
199 // senderState field.
200 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState);
201 assert(buf != NULL);
202 // set up new packet dest & senderState based on values saved
203 // from original request
204 buf->fixResponse(pkt);
205
206 // Check if this packet was expecting a response and it's a nacked
207 // packet, in which case we will never being seeing it
208 if (buf->expectResponse && pkt->wasNacked())
209 --outstandingResponses;
210
| 1
2/*
3 * Copyright (c) 2006 The Regents of The University of Michigan
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Ali Saidi
30 * Steve Reinhardt
31 */
32
33/**
34 * @file
35 * Definition of a simple bus bridge without buffering.
36 */
37
38#include <algorithm>
39
40#include "base/trace.hh"
41#include "mem/bridge.hh"
42#include "sim/builder.hh"
43
44Bridge::BridgePort::BridgePort(const std::string &_name,
45 Bridge *_bridge, BridgePort *_otherPort,
46 int _delay, int _nack_delay, int _req_limit,
47 int _resp_limit, bool fix_partial_write)
48 : Port(_name), bridge(_bridge), otherPort(_otherPort),
49 delay(_delay), nackDelay(_nack_delay), fixPartialWrite(fix_partial_write),
50 outstandingResponses(0), queuedRequests(0), inRetry(false),
51 reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this)
52{
53}
54
55Bridge::Bridge(Params *p)
56 : MemObject(p->name),
57 portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay,
58 p->req_size_a, p->resp_size_a, p->fix_partial_write_a),
59 portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay,
60 p->req_size_b, p->resp_size_b, p->fix_partial_write_b),
61 ackWrites(p->write_ack), _params(p)
62{
63 if (ackWrites)
64 panic("No support for acknowledging writes\n");
65}
66
67Port *
68Bridge::getPort(const std::string &if_name, int idx)
69{
70 BridgePort *port;
71
72 if (if_name == "side_a")
73 port = &portA;
74 else if (if_name == "side_b")
75 port = &portB;
76 else
77 return NULL;
78
79 if (port->getPeer() != NULL)
80 panic("bridge side %s already connected to.", if_name);
81 return port;
82}
83
84
85void
86Bridge::init()
87{
88 // Make sure that both sides are connected to.
89 if (portA.getPeer() == NULL || portB.getPeer() == NULL)
90 fatal("Both ports of bus bridge are not connected to a bus.\n");
91
92 if (portA.peerBlockSize() != portB.peerBlockSize())
93 fatal("Busses don't have the same block size... Not supported.\n");
94}
95
96bool
97Bridge::BridgePort::respQueueFull()
98{
99 assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit);
100 return outstandingResponses >= respQueueLimit;
101}
102
103bool
104Bridge::BridgePort::reqQueueFull()
105{
106 assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit);
107 return queuedRequests >= reqQueueLimit;
108}
109
110/** Function called by the port when the bus is receiving a Timing
111 * transaction.*/
112bool
113Bridge::BridgePort::recvTiming(PacketPtr pkt)
114{
115 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
116 pkt->getSrc(), pkt->getDest(), pkt->getAddr());
117
118 DPRINTF(BusBridge, "Local queue size: %d outreq: %d outresp: %d\n",
119 sendQueue.size(), queuedRequests, outstandingResponses);
120 DPRINTF(BusBridge, "Remove queue size: %d outreq: %d outresp: %d\n",
121 otherPort->sendQueue.size(), otherPort->queuedRequests,
122 otherPort->outstandingResponses);
123
124 if (pkt->isRequest() && otherPort->reqQueueFull() && !pkt->wasNacked()) {
125 DPRINTF(BusBridge, "Remote queue full, nacking\n");
126 nackRequest(pkt);
127 return true;
128 }
129
130 if (pkt->needsResponse() && !pkt->wasNacked())
131 if (respQueueFull()) {
132 DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n");
133 DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n",
134 sendQueue.size(), queuedRequests, outstandingResponses);
135 nackRequest(pkt);
136 return true;
137 } else {
138 DPRINTF(BusBridge, "Request Needs response, reserving space\n");
139 ++outstandingResponses;
140 }
141
142 otherPort->queueForSendTiming(pkt);
143
144 return true;
145}
146
147void
148Bridge::BridgePort::nackRequest(PacketPtr pkt)
149{
150 // Nack the packet
151 pkt->setNacked();
152 pkt->setDest(pkt->getSrc());
153
154 //put it on the list to send
155 Tick readyTime = curTick + nackDelay;
156 PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true);
157
158 // nothing on the list, add it and we're done
159 if (sendQueue.empty()) {
160 assert(!sendEvent.scheduled());
161 sendEvent.schedule(readyTime);
162 sendQueue.push_back(buf);
163 return;
164 }
165
166 assert(sendEvent.scheduled() || inRetry);
167
168 // does it go at the end?
169 if (readyTime >= sendQueue.back()->ready) {
170 sendQueue.push_back(buf);
171 return;
172 }
173
174 // ok, somewhere in the middle, fun
175 std::list<PacketBuffer*>::iterator i = sendQueue.begin();
176 std::list<PacketBuffer*>::iterator end = sendQueue.end();
177 std::list<PacketBuffer*>::iterator begin = sendQueue.begin();
178 bool done = false;
179
180 while (i != end && !done) {
181 if (readyTime < (*i)->ready) {
182 if (i == begin)
183 sendEvent.reschedule(readyTime);
184 sendQueue.insert(i,buf);
185 done = true;
186 }
187 i++;
188 }
189 assert(done);
190}
191
192
193void
194Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
195{
196 if (pkt->isResponse() || pkt->wasNacked()) {
197 // This is a response for a request we forwarded earlier. The
198 // corresponding PacketBuffer should be stored in the packet's
199 // senderState field.
200 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState);
201 assert(buf != NULL);
202 // set up new packet dest & senderState based on values saved
203 // from original request
204 buf->fixResponse(pkt);
205
206 // Check if this packet was expecting a response and it's a nacked
207 // packet, in which case we will never being seeing it
208 if (buf->expectResponse && pkt->wasNacked())
209 --outstandingResponses;
210
|
229
230 // If we're about to put this packet at the head of the queue, we
231 // need to schedule an event to do the transmit. Otherwise there
232 // should already be an event scheduled for sending the head
233 // packet.
234 if (sendQueue.empty()) {
235 sendEvent.schedule(readyTime);
236 }
237 sendQueue.push_back(buf);
238}
239
240void
241Bridge::BridgePort::trySend()
242{
243 assert(!sendQueue.empty());
244
245 PacketBuffer *buf = sendQueue.front();
246
247 assert(buf->ready <= curTick);
248
249 PacketPtr pkt = buf->pkt;
250
251 // Ugly! @todo When multilevel coherence works this will be removed
252 if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite &&
253 !pkt->wasNacked()) {
254 PacketPtr funcPkt = new Packet(pkt->req, MemCmd::WriteReq,
255 Packet::Broadcast);
256 funcPkt->dataStatic(pkt->getPtr<uint8_t>());
257 sendFunctional(funcPkt);
258 pkt->cmd = MemCmd::WriteReq;
259 delete funcPkt;
260 }
261
262 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n",
263 buf->origSrc, pkt->getDest(), pkt->getAddr());
264
265 bool wasReq = pkt->isRequest();
266 bool wasNacked = pkt->wasNacked();
267
268 if (sendTiming(pkt)) {
269 // send successful
270 sendQueue.pop_front();
271 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
272
273 if (buf->expectResponse) {
274 // Must wait for response
275 DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
276 outstandingResponses);
277 } else {
278 // no response expected... deallocate packet buffer now.
279 DPRINTF(BusBridge, " successful: no response expected\n");
280 delete buf;
281 }
282
283 if (!wasNacked) {
284 if (wasReq)
285 --queuedRequests;
286 else
287 --outstandingResponses;
288 }
289
290 // If there are more packets to send, schedule event to try again.
291 if (!sendQueue.empty()) {
292 buf = sendQueue.front();
293 DPRINTF(BusBridge, "Scheduling next send\n");
294 sendEvent.schedule(std::max(buf->ready, curTick + 1));
295 }
296 } else {
297 DPRINTF(BusBridge, " unsuccessful\n");
298 inRetry = true;
299 }
300 DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n",
301 sendQueue.size(), queuedRequests, outstandingResponses);
302}
303
304
305void
306Bridge::BridgePort::recvRetry()
307{
308 inRetry = false;
309 Tick nextReady = sendQueue.front()->ready;
310 if (nextReady <= curTick)
311 trySend();
312 else
313 sendEvent.schedule(nextReady);
314}
315
316/** Function called by the port when the bus is receiving a Atomic
317 * transaction.*/
318Tick
319Bridge::BridgePort::recvAtomic(PacketPtr pkt)
320{
321 // fix partial atomic writes... similar to the timing code that does the
322 // same... will be removed once our code gets this right
323 if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite) {
324
325 PacketPtr funcPkt = new Packet(pkt->req, MemCmd::WriteReq,
326 Packet::Broadcast);
327 funcPkt->dataStatic(pkt->getPtr<uint8_t>());
328 otherPort->sendFunctional(funcPkt);
329 delete funcPkt;
330 pkt->cmd = MemCmd::WriteReq;
331 }
332 return delay + otherPort->sendAtomic(pkt);
333}
334
335/** Function called by the port when the bus is receiving a Functional
336 * transaction.*/
337void
338Bridge::BridgePort::recvFunctional(PacketPtr pkt)
339{
340 std::list<PacketBuffer*>::iterator i;
341
342 for (i = sendQueue.begin(); i != sendQueue.end(); ++i) {
343 if (pkt->checkFunctional((*i)->pkt))
344 return;
345 }
346
347 // fall through if pkt still not satisfied
348 otherPort->sendFunctional(pkt);
349}
350
351/** Function called by the port when the bus is receiving a status change.*/
352void
353Bridge::BridgePort::recvStatusChange(Port::Status status)
354{
355 otherPort->sendStatusChange(status);
356}
357
358void
359Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp,
360 bool &snoop)
361{
362 otherPort->getPeerAddressRanges(resp, snoop);
363 // we don't allow snooping across bridges
364 snoop = false;
365}
366
367BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge)
368
369 Param<int> req_size_a;
370 Param<int> req_size_b;
371 Param<int> resp_size_a;
372 Param<int> resp_size_b;
373 Param<Tick> delay;
374 Param<Tick> nack_delay;
375 Param<bool> write_ack;
376 Param<bool> fix_partial_write_a;
377 Param<bool> fix_partial_write_b;
378
379END_DECLARE_SIM_OBJECT_PARAMS(Bridge)
380
381BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge)
382
383 INIT_PARAM(req_size_a, "The size of the queue for requests coming into side a"),
384 INIT_PARAM(req_size_b, "The size of the queue for requests coming into side b"),
385 INIT_PARAM(resp_size_a, "The size of the queue for responses coming into side a"),
386 INIT_PARAM(resp_size_b, "The size of the queue for responses coming into side b"),
387 INIT_PARAM(delay, "The miminum delay to cross this bridge"),
388 INIT_PARAM(nack_delay, "The minimum delay to nack a packet"),
389 INIT_PARAM(write_ack, "Acknowledge any writes that are received."),
390 INIT_PARAM(fix_partial_write_a, "Fixup any partial block writes that are received"),
391 INIT_PARAM(fix_partial_write_b, "Fixup any partial block writes that are received")
392
393END_INIT_SIM_OBJECT_PARAMS(Bridge)
394
395CREATE_SIM_OBJECT(Bridge)
396{
397 Bridge::Params *p = new Bridge::Params;
398 p->name = getInstanceName();
399 p->req_size_a = req_size_a;
400 p->req_size_b = req_size_b;
401 p->resp_size_a = resp_size_a;
402 p->resp_size_b = resp_size_b;
403 p->delay = delay;
404 p->nack_delay = nack_delay;
405 p->write_ack = write_ack;
406 p->fix_partial_write_a = fix_partial_write_a;
407 p->fix_partial_write_b = fix_partial_write_b;
408 return new Bridge(p);
409}
410
411REGISTER_SIM_OBJECT("Bridge", Bridge)
412
413
| 224
225 // If we're about to put this packet at the head of the queue, we
226 // need to schedule an event to do the transmit. Otherwise there
227 // should already be an event scheduled for sending the head
228 // packet.
229 if (sendQueue.empty()) {
230 sendEvent.schedule(readyTime);
231 }
232 sendQueue.push_back(buf);
233}
234
235void
236Bridge::BridgePort::trySend()
237{
238 assert(!sendQueue.empty());
239
240 PacketBuffer *buf = sendQueue.front();
241
242 assert(buf->ready <= curTick);
243
244 PacketPtr pkt = buf->pkt;
245
246 // Ugly! @todo When multilevel coherence works this will be removed
247 if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite &&
248 !pkt->wasNacked()) {
249 PacketPtr funcPkt = new Packet(pkt->req, MemCmd::WriteReq,
250 Packet::Broadcast);
251 funcPkt->dataStatic(pkt->getPtr<uint8_t>());
252 sendFunctional(funcPkt);
253 pkt->cmd = MemCmd::WriteReq;
254 delete funcPkt;
255 }
256
257 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n",
258 buf->origSrc, pkt->getDest(), pkt->getAddr());
259
260 bool wasReq = pkt->isRequest();
261 bool wasNacked = pkt->wasNacked();
262
263 if (sendTiming(pkt)) {
264 // send successful
265 sendQueue.pop_front();
266 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
267
268 if (buf->expectResponse) {
269 // Must wait for response
270 DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
271 outstandingResponses);
272 } else {
273 // no response expected... deallocate packet buffer now.
274 DPRINTF(BusBridge, " successful: no response expected\n");
275 delete buf;
276 }
277
278 if (!wasNacked) {
279 if (wasReq)
280 --queuedRequests;
281 else
282 --outstandingResponses;
283 }
284
285 // If there are more packets to send, schedule event to try again.
286 if (!sendQueue.empty()) {
287 buf = sendQueue.front();
288 DPRINTF(BusBridge, "Scheduling next send\n");
289 sendEvent.schedule(std::max(buf->ready, curTick + 1));
290 }
291 } else {
292 DPRINTF(BusBridge, " unsuccessful\n");
293 inRetry = true;
294 }
295 DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n",
296 sendQueue.size(), queuedRequests, outstandingResponses);
297}
298
299
300void
301Bridge::BridgePort::recvRetry()
302{
303 inRetry = false;
304 Tick nextReady = sendQueue.front()->ready;
305 if (nextReady <= curTick)
306 trySend();
307 else
308 sendEvent.schedule(nextReady);
309}
310
311/** Function called by the port when the bus is receiving a Atomic
312 * transaction.*/
313Tick
314Bridge::BridgePort::recvAtomic(PacketPtr pkt)
315{
316 // fix partial atomic writes... similar to the timing code that does the
317 // same... will be removed once our code gets this right
318 if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite) {
319
320 PacketPtr funcPkt = new Packet(pkt->req, MemCmd::WriteReq,
321 Packet::Broadcast);
322 funcPkt->dataStatic(pkt->getPtr<uint8_t>());
323 otherPort->sendFunctional(funcPkt);
324 delete funcPkt;
325 pkt->cmd = MemCmd::WriteReq;
326 }
327 return delay + otherPort->sendAtomic(pkt);
328}
329
330/** Function called by the port when the bus is receiving a Functional
331 * transaction.*/
332void
333Bridge::BridgePort::recvFunctional(PacketPtr pkt)
334{
335 std::list<PacketBuffer*>::iterator i;
336
337 for (i = sendQueue.begin(); i != sendQueue.end(); ++i) {
338 if (pkt->checkFunctional((*i)->pkt))
339 return;
340 }
341
342 // fall through if pkt still not satisfied
343 otherPort->sendFunctional(pkt);
344}
345
346/** Function called by the port when the bus is receiving a status change.*/
347void
348Bridge::BridgePort::recvStatusChange(Port::Status status)
349{
350 otherPort->sendStatusChange(status);
351}
352
353void
354Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp,
355 bool &snoop)
356{
357 otherPort->getPeerAddressRanges(resp, snoop);
358 // we don't allow snooping across bridges
359 snoop = false;
360}
361
362BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge)
363
364 Param<int> req_size_a;
365 Param<int> req_size_b;
366 Param<int> resp_size_a;
367 Param<int> resp_size_b;
368 Param<Tick> delay;
369 Param<Tick> nack_delay;
370 Param<bool> write_ack;
371 Param<bool> fix_partial_write_a;
372 Param<bool> fix_partial_write_b;
373
374END_DECLARE_SIM_OBJECT_PARAMS(Bridge)
375
376BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge)
377
378 INIT_PARAM(req_size_a, "The size of the queue for requests coming into side a"),
379 INIT_PARAM(req_size_b, "The size of the queue for requests coming into side b"),
380 INIT_PARAM(resp_size_a, "The size of the queue for responses coming into side a"),
381 INIT_PARAM(resp_size_b, "The size of the queue for responses coming into side b"),
382 INIT_PARAM(delay, "The miminum delay to cross this bridge"),
383 INIT_PARAM(nack_delay, "The minimum delay to nack a packet"),
384 INIT_PARAM(write_ack, "Acknowledge any writes that are received."),
385 INIT_PARAM(fix_partial_write_a, "Fixup any partial block writes that are received"),
386 INIT_PARAM(fix_partial_write_b, "Fixup any partial block writes that are received")
387
388END_INIT_SIM_OBJECT_PARAMS(Bridge)
389
390CREATE_SIM_OBJECT(Bridge)
391{
392 Bridge::Params *p = new Bridge::Params;
393 p->name = getInstanceName();
394 p->req_size_a = req_size_a;
395 p->req_size_b = req_size_b;
396 p->resp_size_a = resp_size_a;
397 p->resp_size_b = resp_size_b;
398 p->delay = delay;
399 p->nack_delay = nack_delay;
400 p->write_ack = write_ack;
401 p->fix_partial_write_a = fix_partial_write_a;
402 p->fix_partial_write_b = fix_partial_write_b;
403 return new Bridge(p);
404}
405
406REGISTER_SIM_OBJECT("Bridge", Bridge)
407
408
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