bridge.hh revision 2643
1/* 2 * Copyright (c) 2006 The Regents of The University of Michigan 3 * All rights reserved. 4 * 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. 15 * 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. 27 */ 28 29/** 30 * @file Decleration of a simple bus bridge object with no buffering 31 */ 32 33#ifndef __MEM_BRIDGE_HH__ 34#define __MEM_BRIDGE_HH__ 35 36#include <string> 37#include <list> 38#include <inttypes.h> 39#include <queue> 40 41 42#include "mem/mem_object.hh" 43#include "mem/packet.hh" 44#include "mem/port.hh" 45#include "sim/eventq.hh" 46 47class Bridge : public MemObject 48{ 49 protected: 50 /** Decleration of the buses port type, one will be instantiated for each 51 of the interfaces connecting to the bus. */ 52 class BridgePort : public Port 53 { 54 /** A pointer to the bridge to which this port belongs. */ 55 Bridge *bridge; 56 57 /** 58 * Pointer to the port on the other side of the bridge 59 * (connected to the other bus). 60 */ 61 BridgePort *otherPort; 62 63 /** Minimum delay though this bridge. */ 64 Tick delay; 65 66 class PacketBuffer : public Packet::SenderState { 67 68 public: 69 Tick ready; 70 Packet *pkt; 71 Packet::SenderState *origSenderState; 72 short origSrc; 73 bool expectResponse; 74 75 PacketBuffer(Packet *_pkt, Tick t) 76 : ready(t), pkt(_pkt), 77 origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()), 78 expectResponse(_pkt->needsResponse()) 79 { 80 pkt->senderState = this; 81 } 82 83 void fixResponse(Packet *pkt) 84 { 85 assert(pkt->senderState == this); 86 pkt->setDest(origSrc); 87 pkt->senderState = origSenderState; 88 } 89 }; 90 91 /** 92 * Outbound packet queue. Packets are held in this queue for a 93 * specified delay to model the processing delay of the 94 * bridge. 95 */ 96 std::list<PacketBuffer*> sendQueue; 97 98 int outstandingResponses; 99 100 /** Max queue size for outbound packets */ 101 int queueLimit; 102 103 /** 104 * Is this side blocked from accepting outbound packets? 105 */ 106 bool queueFull() { return (sendQueue.size() == queueLimit); } 107 108 bool queueForSendTiming(Packet *pkt); 109 110 void finishSend(PacketBuffer *buf); 111 112 /** 113 * Handle send event, scheduled when the packet at the head of 114 * the outbound queue is ready to transmit (for timing 115 * accesses only). 116 */ 117 void trySend(); 118 119 class SendEvent : public Event 120 { 121 BridgePort *port; 122 123 public: 124 SendEvent(BridgePort *p) 125 : Event(&mainEventQueue), port(p) {} 126 127 virtual void process() { port->trySend(); } 128 129 virtual const char *description() { return "bridge send event"; } 130 }; 131 132 SendEvent sendEvent; 133 134 public: 135 136 /** Constructor for the BusPort.*/ 137 BridgePort(const std::string &_name, 138 Bridge *_bridge, BridgePort *_otherPort, 139 int _delay, int _queueLimit); 140 141 protected: 142 143 /** When receiving a timing request from the peer port, 144 pass it to the bridge. */ 145 virtual bool recvTiming(Packet *pkt); 146 147 /** When receiving a retry request from the peer port, 148 pass it to the bridge. */ 149 virtual Packet* recvRetry(); 150 151 /** When receiving a Atomic requestfrom the peer port, 152 pass it to the bridge. */ 153 virtual Tick recvAtomic(Packet *pkt); 154 155 /** When receiving a Functional request from the peer port, 156 pass it to the bridge. */ 157 virtual void recvFunctional(Packet *pkt); 158 159 /** When receiving a status changefrom the peer port, 160 pass it to the bridge. */ 161 virtual void recvStatusChange(Status status); 162 163 /** When receiving a address range request the peer port, 164 pass it to the bridge. */ 165 virtual void getDeviceAddressRanges(AddrRangeList &resp, 166 AddrRangeList &snoop); 167 }; 168 169 BridgePort portA, portB; 170 171 /** If this bridge should acknowledge writes. */ 172 bool ackWrites; 173 174 public: 175 176 /** A function used to return the port associated with this bus object. */ 177 virtual Port *getPort(const std::string &if_name); 178 179 virtual void init(); 180 181 Bridge(const std::string &n, int qsa, int qsb, Tick _delay, int write_ack); 182}; 183 184#endif //__MEM_BUS_HH__ 185