2 * Copyright (c) 2006 The Regents of The University of Michigan
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 "params/Bridge.hh"
49 #include "sim/eventq.hh"
51 class Bridge : public MemObject
54 /** Declaration of the buses port type, one will be instantiated for each
55 of the interfaces connecting to the bus. */
56 class BridgePort : public Port
58 /** A pointer to the bridge to which this port belongs. */
62 * Pointer to the port on the other side of the bridge
63 * (connected to the other bus).
65 BridgePort *otherPort;
67 /** Minimum delay though this bridge. */
70 /** Min delay to respond to a nack. */
75 class PacketBuffer : public Packet::SenderState {
80 Packet::SenderState *origSenderState;
84 PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false)
85 : ready(t), pkt(_pkt),
86 origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()),
87 expectResponse(_pkt->needsResponse() && !nack)
90 if (!pkt->isResponse() && !nack && !pkt->wasNacked())
91 pkt->senderState = this;
94 void fixResponse(PacketPtr pkt)
96 assert(pkt->senderState == this);
97 pkt->setDest(origSrc);
98 pkt->senderState = origSenderState;
103 * Outbound packet queue. Packets are held in this queue for a
104 * specified delay to model the processing delay of the
107 std::list<PacketBuffer*> sendQueue;
109 int outstandingResponses;
112 /** If we're waiting for a retry to happen.*/
115 /** Max queue size for outbound packets */
118 /** Max queue size for reserved responses. */
122 * Is this side blocked from accepting outbound packets?
124 bool respQueueFull();
127 void queueForSendTiming(PacketPtr pkt);
129 void finishSend(PacketBuffer *buf);
131 void nackRequest(PacketPtr pkt);
134 * Handle send event, scheduled when the packet at the head of
135 * the outbound queue is ready to transmit (for timing
140 class SendEvent : public Event
145 SendEvent(BridgePort *p)
146 : Event(&mainEventQueue), port(p) {}
148 virtual void process() { port->trySend(); }
150 virtual const char *description() { return "bridge send"; }
156 /** Constructor for the BusPort.*/
157 BridgePort(const std::string &_name, Bridge *_bridge,
158 BridgePort *_otherPort, int _delay, int _nack_delay,
159 int _req_limit, int _resp_limit, bool fix_partial_write);
163 /** When receiving a timing request from the peer port,
164 pass it to the bridge. */
165 virtual bool recvTiming(PacketPtr pkt);
167 /** When receiving a retry request from the peer port,
168 pass it to the bridge. */
169 virtual void recvRetry();
171 /** When receiving a Atomic requestfrom the peer port,
172 pass it to the bridge. */
173 virtual Tick recvAtomic(PacketPtr pkt);
175 /** When receiving a Functional request from the peer port,
176 pass it to the bridge. */
177 virtual void recvFunctional(PacketPtr pkt);
179 /** When receiving a status changefrom the peer port,
180 pass it to the bridge. */
181 virtual void recvStatusChange(Status status);
183 /** When receiving a address range request the peer port,
184 pass it to the bridge. */
185 virtual void getDeviceAddressRanges(AddrRangeList &resp,
189 BridgePort portA, portB;
191 /** If this bridge should acknowledge writes. */
195 typedef BridgeParams Params;
201 const Params *params() const { return _params; }
203 /** A function used to return the port associated with this bus object. */
204 virtual Port *getPort(const std::string &if_name, int idx = -1);
211 #endif //__MEM_BUS_HH__