bridge.hh revision 4965
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 * Authors: Ali Saidi 29 * Steve Reinhardt 30 */ 31 32/** 33 * @file 34 * Declaration of a simple bus bridge object with no buffering 35 */ 36 37#ifndef __MEM_BRIDGE_HH__ 38#define __MEM_BRIDGE_HH__ 39 40#include <string> 41#include <list> 42#include <inttypes.h> 43#include <queue> 44 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" 50 51class Bridge : public MemObject 52{ 53 protected: 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 57 { 58 /** A pointer to the bridge to which this port belongs. */ 59 Bridge *bridge; 60 61 /** 62 * Pointer to the port on the other side of the bridge 63 * (connected to the other bus). 64 */ 65 BridgePort *otherPort; 66 67 /** Minimum delay though this bridge. */ 68 Tick delay; 69 70 /** Min delay to respond to a nack. */ 71 Tick nackDelay; 72 73 /** Pass ranges from one side of the bridge to the other? */ 74 std::vector<Range<Addr> > filterRanges; 75 76 class PacketBuffer : public Packet::SenderState { 77 78 public: 79 Tick ready; 80 PacketPtr pkt; 81 Packet::SenderState *origSenderState; 82 short origSrc; 83 bool expectResponse; 84 85 PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false) 86 : ready(t), pkt(_pkt), 87 origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()), 88 expectResponse(_pkt->needsResponse() && !nack) 89 90 { 91 if (!pkt->isResponse() && !nack && !pkt->wasNacked()) 92 pkt->senderState = this; 93 } 94 95 void fixResponse(PacketPtr pkt) 96 { 97 assert(pkt->senderState == this); 98 pkt->setDest(origSrc); 99 pkt->senderState = origSenderState; 100 } 101 }; 102 103 /** 104 * Outbound packet queue. Packets are held in this queue for a 105 * specified delay to model the processing delay of the 106 * bridge. 107 */ 108 std::list<PacketBuffer*> sendQueue; 109 110 int outstandingResponses; 111 int queuedRequests; 112 113 /** If we're waiting for a retry to happen.*/ 114 bool inRetry; 115 116 /** Max queue size for outbound packets */ 117 int reqQueueLimit; 118 119 /** Max queue size for reserved responses. */ 120 int respQueueLimit; 121 122 /** 123 * Is this side blocked from accepting outbound packets? 124 */ 125 bool respQueueFull(); 126 bool reqQueueFull(); 127 128 void queueForSendTiming(PacketPtr pkt); 129 130 void finishSend(PacketBuffer *buf); 131 132 void nackRequest(PacketPtr pkt); 133 134 /** 135 * Handle send event, scheduled when the packet at the head of 136 * the outbound queue is ready to transmit (for timing 137 * accesses only). 138 */ 139 void trySend(); 140 141 class SendEvent : public Event 142 { 143 BridgePort *port; 144 145 public: 146 SendEvent(BridgePort *p) 147 : Event(&mainEventQueue), port(p) {} 148 149 virtual void process() { port->trySend(); } 150 151 virtual const char *description() { return "bridge send"; } 152 }; 153 154 SendEvent sendEvent; 155 156 public: 157 /** Constructor for the BusPort.*/ 158 BridgePort(const std::string &_name, Bridge *_bridge, 159 BridgePort *_otherPort, int _delay, int _nack_delay, 160 int _req_limit, int _resp_limit, 161 std::vector<Range<Addr> > filter_ranges); 162 163 protected: 164 165 /** When receiving a timing request from the peer port, 166 pass it to the bridge. */ 167 virtual bool recvTiming(PacketPtr pkt); 168 169 /** When receiving a retry request from the peer port, 170 pass it to the bridge. */ 171 virtual void recvRetry(); 172 173 /** When receiving a Atomic requestfrom the peer port, 174 pass it to the bridge. */ 175 virtual Tick recvAtomic(PacketPtr pkt); 176 177 /** When receiving a Functional request from the peer port, 178 pass it to the bridge. */ 179 virtual void recvFunctional(PacketPtr pkt); 180 181 /** When receiving a status changefrom the peer port, 182 pass it to the bridge. */ 183 virtual void recvStatusChange(Status status); 184 185 /** When receiving a address range request the peer port, 186 pass it to the bridge. */ 187 virtual void getDeviceAddressRanges(AddrRangeList &resp, 188 bool &snoop); 189 }; 190 191 BridgePort portA, portB; 192 193 /** If this bridge should acknowledge writes. */ 194 bool ackWrites; 195 196 public: 197 typedef BridgeParams Params; 198 199 protected: 200 Params *_params; 201 202 public: 203 const Params *params() const { return _params; } 204 205 /** A function used to return the port associated with this bus object. */ 206 virtual Port *getPort(const std::string &if_name, int idx = -1); 207 208 virtual void init(); 209 210 Bridge(Params *p); 211}; 212 213#endif //__MEM_BUS_HH__ 214