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31 * @file Definition of a simple bus bridge without buffering.
36 #include "base/trace.hh"
37 #include "mem/bridge.hh"
38 #include "sim/builder.hh"
40 Bridge::BridgePort::BridgePort(const std::string
&_name
,
41 Bridge
*_bridge
, BridgePort
*_otherPort
,
42 int _delay
, int _queueLimit
)
43 : Port(_name
), bridge(_bridge
), otherPort(_otherPort
),
44 delay(_delay
), outstandingResponses(0),
45 queueLimit(_queueLimit
), sendEvent(this)
49 Bridge::Bridge(const std::string
&n
, int qsa
, int qsb
,
50 Tick _delay
, int write_ack
)
52 portA(n
+ "-portA", this, &portB
, _delay
, qsa
),
53 portB(n
+ "-portB", this, &portA
, _delay
, qsa
),
59 Bridge::getPort(const std::string
&if_name
)
63 if (if_name
== "side_a")
65 else if (if_name
== "side_b")
70 if (port
->getPeer() != NULL
)
71 panic("bridge side %s already connected to.", if_name
);
79 // Make sure that both sides are connected to.
80 if (portA
.getPeer() == NULL
|| portB
.getPeer() == NULL
)
81 panic("Both ports of bus bridge are not connected to a bus.\n");
85 /** Function called by the port when the bus is receiving a Timing
88 Bridge::BridgePort::recvTiming(Packet
*pkt
)
90 DPRINTF(BusBridge
, "recvTiming: src %d dest %d addr 0x%x\n",
91 pkt
->getSrc(), pkt
->getDest(), pkt
->getAddr());
93 if (pkt
->isResponse()) {
94 // This is a response for a request we forwarded earlier. The
95 // corresponding PacketBuffer should be stored in the packet's
97 PacketBuffer
*buf
= dynamic_cast<PacketBuffer
*>(pkt
->senderState
);
99 // set up new packet dest & senderState based on values saved
100 // from original request
101 buf
->fixResponse(pkt
);
102 DPRINTF(BusBridge
, " is response, new dest %d\n", pkt
->getDest());
106 return otherPort
->queueForSendTiming(pkt
);
111 Bridge::BridgePort::queueForSendTiming(Packet
*pkt
)
116 Tick readyTime
= curTick
+ delay
;
117 PacketBuffer
*buf
= new PacketBuffer(pkt
, readyTime
);
119 // If we're about to put this packet at the head of the queue, we
120 // need to schedule an event to do the transmit. Otherwise there
121 // should already be an event scheduled for sending the head
123 if (sendQueue
.empty()) {
124 sendEvent
.schedule(readyTime
);
127 sendQueue
.push_back(buf
);
129 // Did we just become blocked? If yes, let other side know.
131 otherPort
->sendStatusChange(Port::Blocked
);
138 Bridge::BridgePort::finishSend(PacketBuffer
*buf
)
140 if (buf
->expectResponse
) {
141 // Must wait for response. We just need to count outstanding
142 // responses (in case we want to cap them); PacketBuffer
143 // pointer will be recovered on response.
144 ++outstandingResponses
;
145 DPRINTF(BusBridge
, " successful: awaiting response (%d)\n",
146 outstandingResponses
);
148 // no response expected... deallocate packet buffer now.
149 DPRINTF(BusBridge
, " successful: no response expected\n");
153 // If there are more packets to send, schedule event to try again.
154 if (!sendQueue
.empty()) {
155 buf
= sendQueue
.front();
156 sendEvent
.schedule(std::max(buf
->ready
, curTick
+ 1));
162 Bridge::BridgePort::trySend()
164 assert(!sendQueue
.empty());
166 PacketBuffer
*buf
= sendQueue
.front();
168 assert(buf
->ready
<= curTick
);
170 Packet
*pkt
= buf
->pkt
;
172 DPRINTF(BusBridge
, "trySend: origSrc %d dest %d addr 0x%x\n",
173 buf
->origSrc
, pkt
->getDest(), pkt
->getAddr());
175 if (sendTiming(pkt
)) {
177 sendQueue
.pop_front();
178 buf
->pkt
= NULL
; // we no longer own packet, so it's not safe to look at it
181 DPRINTF(BusBridge
, " unsuccessful\n");
187 Bridge::BridgePort::recvRetry()
189 PacketBuffer
*buf
= sendQueue
.front();
190 Packet
*pkt
= buf
->pkt
;
195 /** Function called by the port when the bus is receiving a Atomic
198 Bridge::BridgePort::recvAtomic(Packet
*pkt
)
200 return otherPort
->sendAtomic(pkt
) + delay
;
203 /** Function called by the port when the bus is receiving a Functional
206 Bridge::BridgePort::recvFunctional(Packet
*pkt
)
208 std::list
<PacketBuffer
*>::iterator i
;
209 bool pktContinue
= true;
211 for (i
= sendQueue
.begin(); i
!= sendQueue
.end(); ++i
) {
212 if (pkt
->intersect((*i
)->pkt
)) {
213 pktContinue
&= fixPacket(pkt
, (*i
)->pkt
);
218 otherPort
->sendFunctional(pkt
);
222 /** Function called by the port when the bus is receiving a status change.*/
224 Bridge::BridgePort::recvStatusChange(Port::Status status
)
226 if (status
== Port::Blocked
|| status
== Port::Unblocked
)
229 otherPort
->sendStatusChange(status
);
233 Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList
&resp
,
234 AddrRangeList
&snoop
)
236 otherPort
->getPeerAddressRanges(resp
, snoop
);
239 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge
)
241 Param
<int> queue_size_a
;
242 Param
<int> queue_size_b
;
244 Param
<bool> write_ack
;
246 END_DECLARE_SIM_OBJECT_PARAMS(Bridge
)
248 BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge
)
250 INIT_PARAM(queue_size_a
, "The size of the queue for data coming into side a"),
251 INIT_PARAM(queue_size_b
, "The size of the queue for data coming into side b"),
252 INIT_PARAM(delay
, "The miminum delay to cross this bridge"),
253 INIT_PARAM(write_ack
, "Acknowledge any writes that are received.")
255 END_INIT_SIM_OBJECT_PARAMS(Bridge
)
257 CREATE_SIM_OBJECT(Bridge
)
259 return new Bridge(getInstanceName(), queue_size_a
, queue_size_b
, delay
,
263 REGISTER_SIM_OBJECT("Bridge", Bridge
)