3fa9e5bb9682f3cac5d9550d6da33ed29fcfaa44
3 * Copyright (c) 2006 The Regents of The University of Michigan
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
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13 * neither the name of the copyright holders nor the names of its
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15 * this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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35 * Definition of a simple bus bridge without buffering.
40 #include "base/range_ops.hh"
41 #include "base/trace.hh"
42 #include "mem/bridge.hh"
43 #include "params/Bridge.hh"
45 Bridge::BridgePort::BridgePort(const std::string
&_name
,
46 Bridge
*_bridge
, BridgePort
*_otherPort
,
47 int _delay
, int _nack_delay
, int _req_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)
57 Bridge::Bridge(Params
*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
)
66 panic("No support for acknowledging writes\n");
70 Bridge::getPort(const std::string
&if_name
, int idx
)
74 if (if_name
== "side_a")
76 else if (if_name
== "side_b")
81 if (port
->getPeer() != NULL
)
82 panic("bridge side %s already connected to.", if_name
);
90 // Make sure that both sides are connected to.
91 if (portA
.getPeer() == NULL
|| portB
.getPeer() == NULL
)
92 fatal("Both ports of bus bridge are not connected to a bus.\n");
94 if (portA
.peerBlockSize() != portB
.peerBlockSize())
95 fatal("Busses don't have the same block size... Not supported.\n");
99 Bridge::BridgePort::respQueueFull()
101 assert(outstandingResponses
>= 0 && outstandingResponses
<= respQueueLimit
);
102 return outstandingResponses
>= respQueueLimit
;
106 Bridge::BridgePort::reqQueueFull()
108 assert(queuedRequests
>= 0 && queuedRequests
<= reqQueueLimit
);
109 return queuedRequests
>= reqQueueLimit
;
112 /** Function called by the port when the bus is receiving a Timing
115 Bridge::BridgePort::recvTiming(PacketPtr pkt
)
117 DPRINTF(BusBridge
, "recvTiming: src %d dest %d addr 0x%x\n",
118 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr());
120 DPRINTF(BusBridge
, "Local queue size: %d outreq: %d outresp: %d\n",
121 sendQueue
.size(), queuedRequests
, outstandingResponses
);
122 DPRINTF(BusBridge
, "Remote queue size: %d outreq: %d outresp: %d\n",
123 otherPort
->sendQueue
.size(), otherPort
->queuedRequests
,
124 otherPort
->outstandingResponses
);
126 if (pkt
->isRequest() && otherPort
->reqQueueFull()) {
127 DPRINTF(BusBridge
, "Remote queue full, nacking\n");
132 if (pkt
->needsResponse())
133 if (respQueueFull()) {
134 DPRINTF(BusBridge
, "Local queue full, no space for response, nacking\n");
135 DPRINTF(BusBridge
, "queue size: %d outreq: %d outstanding resp: %d\n",
136 sendQueue
.size(), queuedRequests
, outstandingResponses
);
140 DPRINTF(BusBridge
, "Request Needs response, reserving space\n");
141 ++outstandingResponses
;
144 otherPort
->queueForSendTiming(pkt
);
150 Bridge::BridgePort::nackRequest(PacketPtr pkt
)
153 pkt
->makeTimingResponse();
156 //put it on the list to send
157 Tick readyTime
= curTick
+ nackDelay
;
158 PacketBuffer
*buf
= new PacketBuffer(pkt
, readyTime
, true);
160 // nothing on the list, add it and we're done
161 if (sendQueue
.empty()) {
162 assert(!sendEvent
.scheduled());
163 sendEvent
.schedule(readyTime
);
164 sendQueue
.push_back(buf
);
168 assert(sendEvent
.scheduled() || inRetry
);
170 // does it go at the end?
171 if (readyTime
>= sendQueue
.back()->ready
) {
172 sendQueue
.push_back(buf
);
176 // ok, somewhere in the middle, fun
177 std::list
<PacketBuffer
*>::iterator i
= sendQueue
.begin();
178 std::list
<PacketBuffer
*>::iterator end
= sendQueue
.end();
179 std::list
<PacketBuffer
*>::iterator begin
= sendQueue
.begin();
182 while (i
!= end
&& !done
) {
183 if (readyTime
< (*i
)->ready
) {
185 sendEvent
.reschedule(readyTime
);
186 sendQueue
.insert(i
,buf
);
196 Bridge::BridgePort::queueForSendTiming(PacketPtr pkt
)
198 if (pkt
->isResponse()) {
199 // This is a response for a request we forwarded earlier. The
200 // corresponding PacketBuffer should be stored in the packet's
201 // senderState field.
203 PacketBuffer
*buf
= dynamic_cast<PacketBuffer
*>(pkt
->senderState
);
205 // set up new packet dest & senderState based on values saved
206 // from original request
207 buf
->fixResponse(pkt
);
209 DPRINTF(BusBridge
, "response, new dest %d\n", pkt
->getDest());
214 if (pkt
->isRequest()) {
220 Tick readyTime
= curTick
+ delay
;
221 PacketBuffer
*buf
= new PacketBuffer(pkt
, readyTime
);
223 // If we're about to put this packet at the head of the queue, we
224 // need to schedule an event to do the transmit. Otherwise there
225 // should already be an event scheduled for sending the head
227 if (sendQueue
.empty()) {
228 sendEvent
.schedule(readyTime
);
230 sendQueue
.push_back(buf
);
234 Bridge::BridgePort::trySend()
236 assert(!sendQueue
.empty());
238 PacketBuffer
*buf
= sendQueue
.front();
240 assert(buf
->ready
<= curTick
);
242 PacketPtr pkt
= buf
->pkt
;
244 DPRINTF(BusBridge
, "trySend: origSrc %d dest %d addr 0x%x\n",
245 buf
->origSrc
, pkt
->getDest(), pkt
->getAddr());
247 bool wasReq
= pkt
->isRequest();
248 bool was_nacked_here
= buf
->nackedHere
;
250 // If the send was successful, make sure sender state was set to NULL
251 // otherwise we could get a NACK back of a packet that didn't expect a
252 // response and we would try to use freed memory.
254 Packet::SenderState
*old_sender_state
= pkt
->senderState
;
255 if (pkt
->isRequest() && !buf
->expectResponse
)
256 pkt
->senderState
= NULL
;
258 if (sendTiming(pkt
)) {
260 sendQueue
.pop_front();
261 buf
->pkt
= NULL
; // we no longer own packet, so it's not safe to look at it
263 if (buf
->expectResponse
) {
264 // Must wait for response
265 DPRINTF(BusBridge
, " successful: awaiting response (%d)\n",
266 outstandingResponses
);
268 // no response expected... deallocate packet buffer now.
269 DPRINTF(BusBridge
, " successful: no response expected\n");
275 else if (!was_nacked_here
)
276 --outstandingResponses
;
278 // If there are more packets to send, schedule event to try again.
279 if (!sendQueue
.empty()) {
280 buf
= sendQueue
.front();
281 DPRINTF(BusBridge
, "Scheduling next send\n");
282 sendEvent
.schedule(std::max(buf
->ready
, curTick
+ 1));
285 DPRINTF(BusBridge
, " unsuccessful\n");
286 pkt
->senderState
= old_sender_state
;
290 DPRINTF(BusBridge
, "trySend: queue size: %d outreq: %d outstanding resp: %d\n",
291 sendQueue
.size(), queuedRequests
, outstandingResponses
);
296 Bridge::BridgePort::recvRetry()
299 Tick nextReady
= sendQueue
.front()->ready
;
300 if (nextReady
<= curTick
)
303 sendEvent
.schedule(nextReady
);
306 /** Function called by the port when the bus is receiving a Atomic
309 Bridge::BridgePort::recvAtomic(PacketPtr pkt
)
311 return delay
+ otherPort
->sendAtomic(pkt
);
314 /** Function called by the port when the bus is receiving a Functional
317 Bridge::BridgePort::recvFunctional(PacketPtr pkt
)
319 std::list
<PacketBuffer
*>::iterator i
;
321 for (i
= sendQueue
.begin(); i
!= sendQueue
.end(); ++i
) {
322 if (pkt
->checkFunctional((*i
)->pkt
))
326 // fall through if pkt still not satisfied
327 otherPort
->sendFunctional(pkt
);
330 /** Function called by the port when the bus is receiving a status change.*/
332 Bridge::BridgePort::recvStatusChange(Port::Status status
)
334 otherPort
->sendStatusChange(status
);
338 Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList
&resp
,
341 otherPort
->getPeerAddressRanges(resp
, snoop
);
342 FilterRangeList(filterRanges
, resp
);
343 // we don't allow snooping across bridges
348 BridgeParams::create()
350 return new Bridge(this);