bridge.hh revision 5386
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 "base/fast_alloc.hh" 46#include "mem/mem_object.hh" 47#include "mem/packet.hh" 48#include "mem/port.hh" 49#include "params/Bridge.hh" 50#include "sim/eventq.hh" 51 52class Bridge : public MemObject 53{ 54 protected: 55 /** Declaration of the buses port type, one will be instantiated for each 56 of the interfaces connecting to the bus. */ 57 class BridgePort : public Port 58 { 59 /** A pointer to the bridge to which this port belongs. */ 60 Bridge *bridge; 61 62 /** 63 * Pointer to the port on the other side of the bridge 64 * (connected to the other bus). 65 */ 66 BridgePort *otherPort; 67 68 /** Minimum delay though this bridge. */ 69 Tick delay; 70 71 /** Min delay to respond to a nack. */ 72 Tick nackDelay; 73 74 /** Pass ranges from one side of the bridge to the other? */ 75 std::vector<Range<Addr> > filterRanges; 76 77 class PacketBuffer : public Packet::SenderState, public FastAlloc { 78 79 public: 80 Tick ready; 81 PacketPtr pkt; 82 bool nackedHere; 83 Packet::SenderState *origSenderState; 84 short origSrc; 85 bool expectResponse; 86 87 PacketBuffer(PacketPtr _pkt, Tick t, bool nack = false) 88 : ready(t), pkt(_pkt), nackedHere(nack), 89 origSenderState(_pkt->senderState), 90 origSrc(nack ? _pkt->getDest() : _pkt->getSrc() ), 91 expectResponse(_pkt->needsResponse() && !nack) 92 93 { 94 if (!pkt->isResponse() && !nack) 95 pkt->senderState = this; 96 } 97 98 void fixResponse(PacketPtr pkt) 99 { 100 assert(pkt->senderState == this); 101 pkt->setDest(origSrc); 102 pkt->senderState = origSenderState; 103 } 104 }; 105 106 /** 107 * Outbound packet queue. Packets are held in this queue for a 108 * specified delay to model the processing delay of the 109 * bridge. 110 */ 111 std::list<PacketBuffer*> sendQueue; 112 113 int outstandingResponses; 114 int queuedRequests; 115 116 /** If we're waiting for a retry to happen.*/ 117 bool inRetry; 118 119 /** Max queue size for outbound packets */ 120 int reqQueueLimit; 121 122 /** Max queue size for reserved responses. */ 123 int respQueueLimit; 124 125 /** 126 * Is this side blocked from accepting outbound packets? 127 */ 128 bool respQueueFull(); 129 bool reqQueueFull(); 130 131 void queueForSendTiming(PacketPtr pkt); 132 133 void finishSend(PacketBuffer *buf); 134 135 void nackRequest(PacketPtr pkt); 136 137 /** 138 * Handle send event, scheduled when the packet at the head of 139 * the outbound queue is ready to transmit (for timing 140 * accesses only). 141 */ 142 void trySend(); 143 144 class SendEvent : public Event 145 { 146 BridgePort *port; 147 148 public: 149 SendEvent(BridgePort *p) 150 : Event(&mainEventQueue), port(p) {} 151 152 virtual void process() { port->trySend(); } 153 154 virtual const char *description() const { return "bridge send"; } 155 }; 156 157 SendEvent sendEvent; 158 159 public: 160 /** Constructor for the BusPort.*/ 161 BridgePort(const std::string &_name, Bridge *_bridge, 162 BridgePort *_otherPort, int _delay, int _nack_delay, 163 int _req_limit, int _resp_limit, 164 std::vector<Range<Addr> > filter_ranges); 165 166 protected: 167 168 /** When receiving a timing request from the peer port, 169 pass it to the bridge. */ 170 virtual bool recvTiming(PacketPtr pkt); 171 172 /** When receiving a retry request from the peer port, 173 pass it to the bridge. */ 174 virtual void recvRetry(); 175 176 /** When receiving a Atomic requestfrom the peer port, 177 pass it to the bridge. */ 178 virtual Tick recvAtomic(PacketPtr pkt); 179 180 /** When receiving a Functional request from the peer port, 181 pass it to the bridge. */ 182 virtual void recvFunctional(PacketPtr pkt); 183 184 /** When receiving a status changefrom the peer port, 185 pass it to the bridge. */ 186 virtual void recvStatusChange(Status status); 187 188 /** When receiving a address range request the peer port, 189 pass it to the bridge. */ 190 virtual void getDeviceAddressRanges(AddrRangeList &resp, 191 bool &snoop); 192 }; 193 194 BridgePort portA, portB; 195 196 /** If this bridge should acknowledge writes. */ 197 bool ackWrites; 198 199 public: 200 typedef BridgeParams Params; 201 202 protected: 203 Params *_params; 204 205 public: 206 const Params *params() const { return _params; } 207 208 /** A function used to return the port associated with this bus object. */ 209 virtual Port *getPort(const std::string &if_name, int idx = -1); 210 211 virtual void init(); 212 213 Bridge(Params *p); 214}; 215 216#endif //__MEM_BUS_HH__ 217