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/range_ops.hh"
41#include "base/trace.hh"
42#include "mem/bridge.hh"
43#include "params/Bridge.hh"
44
45Bridge::BridgePort::BridgePort(const std::string &_name,
46 Bridge *_bridge, BridgePort *_otherPort,
47 int _delay, int _nack_delay, int _req_limit,
48 int _resp_limit,
49 std::vector<Range<Addr> > filter_ranges)
50 : Port(_name), bridge(_bridge), otherPort(_otherPort),
51 delay(_delay), nackDelay(_nack_delay), filterRanges(filter_ranges),
52 outstandingResponses(0), queuedRequests(0), inRetry(false),
53 reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this)
54{
55}
56
57Bridge::Bridge(Params *p)
58 : MemObject(p),
59 portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay,
60 p->req_size_a, p->resp_size_a, p->filter_ranges_a),
61 portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay,
62 p->req_size_b, p->resp_size_b, p->filter_ranges_b),
63 ackWrites(p->write_ack), _params(p)
64{
65 if (ackWrites)
66 panic("No support for acknowledging writes\n");
67}
68
69Port *
70Bridge::getPort(const std::string &if_name, int idx)
71{
72 BridgePort *port;
73
74 if (if_name == "side_a")
75 port = &portA;
76 else if (if_name == "side_b")
77 port = &portB;
78 else
79 return NULL;
80
81 if (port->getPeer() != NULL && !port->getPeer()->isDefaultPort())
82 panic("bridge side %s already connected to %s.",
83 if_name, port->getPeer()->name());
84 return port;
85}
86
87
88void
89Bridge::init()
90{
91 // Make sure that both sides are connected to.
92 if (portA.getPeer() == NULL || portB.getPeer() == NULL)
93 fatal("Both ports of bus bridge are not connected to a bus.\n");
94
95 if (portA.peerBlockSize() != portB.peerBlockSize())
96 fatal("Busses don't have the same block size... Not supported.\n");
97}
98
99bool
100Bridge::BridgePort::respQueueFull()
101{
102 assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit);
103 return outstandingResponses >= respQueueLimit;
104}
105
106bool
107Bridge::BridgePort::reqQueueFull()
108{
109 assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit);
110 return queuedRequests >= reqQueueLimit;
111}
112
113/** Function called by the port when the bus is receiving a Timing
114 * transaction.*/
115bool
116Bridge::BridgePort::recvTiming(PacketPtr pkt)
117{
118 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
119 pkt->getSrc(), pkt->getDest(), pkt->getAddr());
120
121 DPRINTF(BusBridge, "Local queue size: %d outreq: %d outresp: %d\n",
122 sendQueue.size(), queuedRequests, outstandingResponses);
123 DPRINTF(BusBridge, "Remote queue size: %d outreq: %d outresp: %d\n",
124 otherPort->sendQueue.size(), otherPort->queuedRequests,
125 otherPort->outstandingResponses);
126
127 if (pkt->isRequest() && otherPort->reqQueueFull()) {
128 DPRINTF(BusBridge, "Remote queue full, nacking\n");
129 nackRequest(pkt);
130 return true;
131 }
132
133 if (pkt->needsResponse())
134 if (respQueueFull()) {
135 DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n");
136 DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n",
137 sendQueue.size(), queuedRequests, outstandingResponses);
138 nackRequest(pkt);
139 return true;
140 } else {
141 DPRINTF(BusBridge, "Request Needs response, reserving space\n");
142 ++outstandingResponses;
143 }
144
145 otherPort->queueForSendTiming(pkt);
146
147 return true;
148}
149
150void
151Bridge::BridgePort::nackRequest(PacketPtr pkt)
152{
153 // Nack the packet
154 pkt->makeTimingResponse();
155 pkt->setNacked();
156
157 //put it on the list to send
158 Tick readyTime = curTick + nackDelay;
159 PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true);
160
161 // nothing on the list, add it and we're done
162 if (sendQueue.empty()) {
163 assert(!sendEvent.scheduled());
164 sendEvent.schedule(readyTime);
165 sendQueue.push_back(buf);
166 return;
167 }
168
169 assert(sendEvent.scheduled() || inRetry);
170
171 // does it go at the end?
172 if (readyTime >= sendQueue.back()->ready) {
173 sendQueue.push_back(buf);
174 return;
175 }
176
177 // ok, somewhere in the middle, fun
178 std::list<PacketBuffer*>::iterator i = sendQueue.begin();
179 std::list<PacketBuffer*>::iterator end = sendQueue.end();
180 std::list<PacketBuffer*>::iterator begin = sendQueue.begin();
181 bool done = false;
182
183 while (i != end && !done) {
184 if (readyTime < (*i)->ready) {
185 if (i == begin)
186 sendEvent.reschedule(readyTime);
187 sendQueue.insert(i,buf);
188 done = true;
189 }
190 i++;
191 }
192 assert(done);
193}
194
195
196void
197Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
198{
199 if (pkt->isResponse()) {
200 // This is a response for a request we forwarded earlier. The
201 // corresponding PacketBuffer should be stored in the packet's
202 // senderState field.
203
204 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState);
205 assert(buf != NULL);
206 // set up new packet dest & senderState based on values saved
207 // from original request
208 buf->fixResponse(pkt);
209
210 DPRINTF(BusBridge, "response, new dest %d\n", pkt->getDest());
211 delete buf;
212 }
213
214
215 if (pkt->isRequest()) {
216 ++queuedRequests;
217 }
218
219
220
221 Tick readyTime = curTick + delay;
222 PacketBuffer *buf = new PacketBuffer(pkt, readyTime);
223
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
227 // packet.
228 if (sendQueue.empty()) {
229 sendEvent.schedule(readyTime);
230 }
231 sendQueue.push_back(buf);
232}
233
234void
235Bridge::BridgePort::trySend()
236{
237 assert(!sendQueue.empty());
238
239 PacketBuffer *buf = sendQueue.front();
240
241 assert(buf->ready <= curTick);
242
243 PacketPtr pkt = buf->pkt;
244
245 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n",
246 buf->origSrc, pkt->getDest(), pkt->getAddr());
247
248 bool wasReq = pkt->isRequest();
249 bool was_nacked_here = buf->nackedHere;
250
251 // If the send was successful, make sure sender state was set to NULL
252 // otherwise we could get a NACK back of a packet that didn't expect a
253 // response and we would try to use freed memory.
254
255 Packet::SenderState *old_sender_state = pkt->senderState;
256 if (pkt->isRequest() && !buf->expectResponse)
257 pkt->senderState = NULL;
258
259 if (sendTiming(pkt)) {
260 // send successful
261 sendQueue.pop_front();
262 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
263
264 if (buf->expectResponse) {
265 // Must wait for response
266 DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
267 outstandingResponses);
268 } else {
269 // no response expected... deallocate packet buffer now.
270 DPRINTF(BusBridge, " successful: no response expected\n");
271 delete buf;
272 }
273
274 if (wasReq)
275 --queuedRequests;
276 else if (!was_nacked_here)
277 --outstandingResponses;
278
279 // If there are more packets to send, schedule event to try again.
280 if (!sendQueue.empty()) {
281 buf = sendQueue.front();
282 DPRINTF(BusBridge, "Scheduling next send\n");
283 sendEvent.schedule(std::max(buf->ready, curTick + 1));
284 }
285 } else {
286 DPRINTF(BusBridge, " unsuccessful\n");
287 pkt->senderState = old_sender_state;
288 inRetry = true;
289 }
290
291 DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n",
292 sendQueue.size(), queuedRequests, outstandingResponses);
293}
294
295
296void
297Bridge::BridgePort::recvRetry()
298{
299 inRetry = false;
300 Tick nextReady = sendQueue.front()->ready;
301 if (nextReady <= curTick)
302 trySend();
303 else
304 sendEvent.schedule(nextReady);
305}
306
307/** Function called by the port when the bus is receiving a Atomic
308 * transaction.*/
309Tick
310Bridge::BridgePort::recvAtomic(PacketPtr pkt)
311{
312 return delay + otherPort->sendAtomic(pkt);
313}
314
315/** Function called by the port when the bus is receiving a Functional
316 * transaction.*/
317void
318Bridge::BridgePort::recvFunctional(PacketPtr pkt)
319{
320 std::list<PacketBuffer*>::iterator i;
321
| 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/range_ops.hh"
41#include "base/trace.hh"
42#include "mem/bridge.hh"
43#include "params/Bridge.hh"
44
45Bridge::BridgePort::BridgePort(const std::string &_name,
46 Bridge *_bridge, BridgePort *_otherPort,
47 int _delay, int _nack_delay, int _req_limit,
48 int _resp_limit,
49 std::vector<Range<Addr> > filter_ranges)
50 : Port(_name), bridge(_bridge), otherPort(_otherPort),
51 delay(_delay), nackDelay(_nack_delay), filterRanges(filter_ranges),
52 outstandingResponses(0), queuedRequests(0), inRetry(false),
53 reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this)
54{
55}
56
57Bridge::Bridge(Params *p)
58 : MemObject(p),
59 portA(p->name + "-portA", this, &portB, p->delay, p->nack_delay,
60 p->req_size_a, p->resp_size_a, p->filter_ranges_a),
61 portB(p->name + "-portB", this, &portA, p->delay, p->nack_delay,
62 p->req_size_b, p->resp_size_b, p->filter_ranges_b),
63 ackWrites(p->write_ack), _params(p)
64{
65 if (ackWrites)
66 panic("No support for acknowledging writes\n");
67}
68
69Port *
70Bridge::getPort(const std::string &if_name, int idx)
71{
72 BridgePort *port;
73
74 if (if_name == "side_a")
75 port = &portA;
76 else if (if_name == "side_b")
77 port = &portB;
78 else
79 return NULL;
80
81 if (port->getPeer() != NULL && !port->getPeer()->isDefaultPort())
82 panic("bridge side %s already connected to %s.",
83 if_name, port->getPeer()->name());
84 return port;
85}
86
87
88void
89Bridge::init()
90{
91 // Make sure that both sides are connected to.
92 if (portA.getPeer() == NULL || portB.getPeer() == NULL)
93 fatal("Both ports of bus bridge are not connected to a bus.\n");
94
95 if (portA.peerBlockSize() != portB.peerBlockSize())
96 fatal("Busses don't have the same block size... Not supported.\n");
97}
98
99bool
100Bridge::BridgePort::respQueueFull()
101{
102 assert(outstandingResponses >= 0 && outstandingResponses <= respQueueLimit);
103 return outstandingResponses >= respQueueLimit;
104}
105
106bool
107Bridge::BridgePort::reqQueueFull()
108{
109 assert(queuedRequests >= 0 && queuedRequests <= reqQueueLimit);
110 return queuedRequests >= reqQueueLimit;
111}
112
113/** Function called by the port when the bus is receiving a Timing
114 * transaction.*/
115bool
116Bridge::BridgePort::recvTiming(PacketPtr pkt)
117{
118 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
119 pkt->getSrc(), pkt->getDest(), pkt->getAddr());
120
121 DPRINTF(BusBridge, "Local queue size: %d outreq: %d outresp: %d\n",
122 sendQueue.size(), queuedRequests, outstandingResponses);
123 DPRINTF(BusBridge, "Remote queue size: %d outreq: %d outresp: %d\n",
124 otherPort->sendQueue.size(), otherPort->queuedRequests,
125 otherPort->outstandingResponses);
126
127 if (pkt->isRequest() && otherPort->reqQueueFull()) {
128 DPRINTF(BusBridge, "Remote queue full, nacking\n");
129 nackRequest(pkt);
130 return true;
131 }
132
133 if (pkt->needsResponse())
134 if (respQueueFull()) {
135 DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n");
136 DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n",
137 sendQueue.size(), queuedRequests, outstandingResponses);
138 nackRequest(pkt);
139 return true;
140 } else {
141 DPRINTF(BusBridge, "Request Needs response, reserving space\n");
142 ++outstandingResponses;
143 }
144
145 otherPort->queueForSendTiming(pkt);
146
147 return true;
148}
149
150void
151Bridge::BridgePort::nackRequest(PacketPtr pkt)
152{
153 // Nack the packet
154 pkt->makeTimingResponse();
155 pkt->setNacked();
156
157 //put it on the list to send
158 Tick readyTime = curTick + nackDelay;
159 PacketBuffer *buf = new PacketBuffer(pkt, readyTime, true);
160
161 // nothing on the list, add it and we're done
162 if (sendQueue.empty()) {
163 assert(!sendEvent.scheduled());
164 sendEvent.schedule(readyTime);
165 sendQueue.push_back(buf);
166 return;
167 }
168
169 assert(sendEvent.scheduled() || inRetry);
170
171 // does it go at the end?
172 if (readyTime >= sendQueue.back()->ready) {
173 sendQueue.push_back(buf);
174 return;
175 }
176
177 // ok, somewhere in the middle, fun
178 std::list<PacketBuffer*>::iterator i = sendQueue.begin();
179 std::list<PacketBuffer*>::iterator end = sendQueue.end();
180 std::list<PacketBuffer*>::iterator begin = sendQueue.begin();
181 bool done = false;
182
183 while (i != end && !done) {
184 if (readyTime < (*i)->ready) {
185 if (i == begin)
186 sendEvent.reschedule(readyTime);
187 sendQueue.insert(i,buf);
188 done = true;
189 }
190 i++;
191 }
192 assert(done);
193}
194
195
196void
197Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
198{
199 if (pkt->isResponse()) {
200 // This is a response for a request we forwarded earlier. The
201 // corresponding PacketBuffer should be stored in the packet's
202 // senderState field.
203
204 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState);
205 assert(buf != NULL);
206 // set up new packet dest & senderState based on values saved
207 // from original request
208 buf->fixResponse(pkt);
209
210 DPRINTF(BusBridge, "response, new dest %d\n", pkt->getDest());
211 delete buf;
212 }
213
214
215 if (pkt->isRequest()) {
216 ++queuedRequests;
217 }
218
219
220
221 Tick readyTime = curTick + delay;
222 PacketBuffer *buf = new PacketBuffer(pkt, readyTime);
223
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
227 // packet.
228 if (sendQueue.empty()) {
229 sendEvent.schedule(readyTime);
230 }
231 sendQueue.push_back(buf);
232}
233
234void
235Bridge::BridgePort::trySend()
236{
237 assert(!sendQueue.empty());
238
239 PacketBuffer *buf = sendQueue.front();
240
241 assert(buf->ready <= curTick);
242
243 PacketPtr pkt = buf->pkt;
244
245 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n",
246 buf->origSrc, pkt->getDest(), pkt->getAddr());
247
248 bool wasReq = pkt->isRequest();
249 bool was_nacked_here = buf->nackedHere;
250
251 // If the send was successful, make sure sender state was set to NULL
252 // otherwise we could get a NACK back of a packet that didn't expect a
253 // response and we would try to use freed memory.
254
255 Packet::SenderState *old_sender_state = pkt->senderState;
256 if (pkt->isRequest() && !buf->expectResponse)
257 pkt->senderState = NULL;
258
259 if (sendTiming(pkt)) {
260 // send successful
261 sendQueue.pop_front();
262 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
263
264 if (buf->expectResponse) {
265 // Must wait for response
266 DPRINTF(BusBridge, " successful: awaiting response (%d)\n",
267 outstandingResponses);
268 } else {
269 // no response expected... deallocate packet buffer now.
270 DPRINTF(BusBridge, " successful: no response expected\n");
271 delete buf;
272 }
273
274 if (wasReq)
275 --queuedRequests;
276 else if (!was_nacked_here)
277 --outstandingResponses;
278
279 // If there are more packets to send, schedule event to try again.
280 if (!sendQueue.empty()) {
281 buf = sendQueue.front();
282 DPRINTF(BusBridge, "Scheduling next send\n");
283 sendEvent.schedule(std::max(buf->ready, curTick + 1));
284 }
285 } else {
286 DPRINTF(BusBridge, " unsuccessful\n");
287 pkt->senderState = old_sender_state;
288 inRetry = true;
289 }
290
291 DPRINTF(BusBridge, "trySend: queue size: %d outreq: %d outstanding resp: %d\n",
292 sendQueue.size(), queuedRequests, outstandingResponses);
293}
294
295
296void
297Bridge::BridgePort::recvRetry()
298{
299 inRetry = false;
300 Tick nextReady = sendQueue.front()->ready;
301 if (nextReady <= curTick)
302 trySend();
303 else
304 sendEvent.schedule(nextReady);
305}
306
307/** Function called by the port when the bus is receiving a Atomic
308 * transaction.*/
309Tick
310Bridge::BridgePort::recvAtomic(PacketPtr pkt)
311{
312 return delay + otherPort->sendAtomic(pkt);
313}
314
315/** Function called by the port when the bus is receiving a Functional
316 * transaction.*/
317void
318Bridge::BridgePort::recvFunctional(PacketPtr pkt)
319{
320 std::list<PacketBuffer*>::iterator i;
321
|