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34 * Declaration of a simple bus bridge object with no buffering
37 #ifndef __MEM_BRIDGE_HH__
38 #define __MEM_BRIDGE_HH__
45 #include "mem/mem_object.hh"
46 #include "mem/packet.hh"
47 #include "mem/port.hh"
48 #include "sim/eventq.hh"
50 class Bridge : public MemObject
53 /** Declaration of the buses port type, one will be instantiated for each
54 of the interfaces connecting to the bus. */
55 class BridgePort : public Port
57 /** A pointer to the bridge to which this port belongs. */
61 * Pointer to the port on the other side of the bridge
62 * (connected to the other bus).
64 BridgePort *otherPort;
66 /** Minimum delay though this bridge. */
69 /** Min delay to respond to a nack. */
74 class PacketBuffer : public Packet::SenderState {
79 Packet::SenderState *origSenderState;
83 PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false)
84 : ready(t), pkt(_pkt),
85 origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()),
86 expectResponse(_pkt->needsResponse() && !nack)
89 if (!pkt->isResponse() && !nack && !pkt->wasNacked())
90 pkt->senderState = this;
93 void fixResponse(PacketPtr pkt)
95 assert(pkt->senderState == this);
96 pkt->setDest(origSrc);
97 pkt->senderState = origSenderState;
102 * Outbound packet queue. Packets are held in this queue for a
103 * specified delay to model the processing delay of the
106 std::list<PacketBuffer*> sendQueue;
108 int outstandingResponses;
111 /** If we're waiting for a retry to happen.*/
114 /** Max queue size for outbound packets */
117 /** Max queue size for reserved responses. */
121 * Is this side blocked from accepting outbound packets?
123 bool respQueueFull();
126 void queueForSendTiming(PacketPtr pkt);
128 void finishSend(PacketBuffer *buf);
130 void nackRequest(PacketPtr pkt);
133 * Handle send event, scheduled when the packet at the head of
134 * the outbound queue is ready to transmit (for timing
139 class SendEvent : public Event
144 SendEvent(BridgePort *p)
145 : Event(&mainEventQueue), port(p) {}
147 virtual void process() { port->trySend(); }
149 virtual const char *description() { return "bridge send"; }
155 /** Constructor for the BusPort.*/
156 BridgePort(const std::string &_name, Bridge *_bridge,
157 BridgePort *_otherPort, int _delay, int _nack_delay,
158 int _req_limit, int _resp_limit, bool fix_partial_write);
162 /** When receiving a timing request from the peer port,
163 pass it to the bridge. */
164 virtual bool recvTiming(PacketPtr pkt);
166 /** When receiving a retry request from the peer port,
167 pass it to the bridge. */
168 virtual void recvRetry();
170 /** When receiving a Atomic requestfrom the peer port,
171 pass it to the bridge. */
172 virtual Tick recvAtomic(PacketPtr pkt);
174 /** When receiving a Functional request from the peer port,
175 pass it to the bridge. */
176 virtual void recvFunctional(PacketPtr pkt);
178 /** When receiving a status changefrom the peer port,
179 pass it to the bridge. */
180 virtual void recvStatusChange(Status status);
182 /** When receiving a address range request the peer port,
183 pass it to the bridge. */
184 virtual void getDeviceAddressRanges(AddrRangeList &resp,
188 BridgePort portA, portB;
190 /** If this bridge should acknowledge writes. */
204 bool fix_partial_write_a;
205 bool fix_partial_write_b;
212 const Params *params() const { return _params; }
214 /** A function used to return the port associated with this bus object. */
215 virtual Port *getPort(const std::string &if_name, int idx = -1);
222 #endif //__MEM_BUS_HH__