bridge.hh revision 4762:c94e103c83ad
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 bool fixPartialWrite; 74 75 class PacketBuffer : public Packet::SenderState { 76 77 public: 78 Tick ready; 79 PacketPtr pkt; 80 Packet::SenderState *origSenderState; 81 short origSrc; 82 bool expectResponse; 83 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) 88 89 { 90 if (!pkt->isResponse() && !nack && pkt->result != Packet::Nacked) 91 pkt->senderState = this; 92 } 93 94 void fixResponse(PacketPtr pkt) 95 { 96 assert(pkt->senderState == this); 97 pkt->setDest(origSrc); 98 pkt->senderState = origSenderState; 99 } 100 }; 101 102 /** 103 * Outbound packet queue. Packets are held in this queue for a 104 * specified delay to model the processing delay of the 105 * bridge. 106 */ 107 std::list<PacketBuffer*> sendQueue; 108 109 int outstandingResponses; 110 int queuedRequests; 111 112 /** If we're waiting for a retry to happen.*/ 113 bool inRetry; 114 115 /** Max queue size for outbound packets */ 116 int reqQueueLimit; 117 118 /** Max queue size for reserved responses. */ 119 int respQueueLimit; 120 121 /** 122 * Is this side blocked from accepting outbound packets? 123 */ 124 bool respQueueFull(); 125 bool reqQueueFull(); 126 127 void queueForSendTiming(PacketPtr pkt); 128 129 void finishSend(PacketBuffer *buf); 130 131 void nackRequest(PacketPtr pkt); 132 133 /** 134 * Handle send event, scheduled when the packet at the head of 135 * the outbound queue is ready to transmit (for timing 136 * accesses only). 137 */ 138 void trySend(); 139 140 class SendEvent : public Event 141 { 142 BridgePort *port; 143 144 public: 145 SendEvent(BridgePort *p) 146 : Event(&mainEventQueue), port(p) {} 147 148 virtual void process() { port->trySend(); } 149 150 virtual const char *description() { return "bridge send event"; } 151 }; 152 153 SendEvent sendEvent; 154 155 public: 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); 160 161 protected: 162 163 /** When receiving a timing request from the peer port, 164 pass it to the bridge. */ 165 virtual bool recvTiming(PacketPtr pkt); 166 167 /** When receiving a retry request from the peer port, 168 pass it to the bridge. */ 169 virtual void recvRetry(); 170 171 /** When receiving a Atomic requestfrom the peer port, 172 pass it to the bridge. */ 173 virtual Tick recvAtomic(PacketPtr pkt); 174 175 /** When receiving a Functional request from the peer port, 176 pass it to the bridge. */ 177 virtual void recvFunctional(PacketPtr pkt); 178 179 /** When receiving a status changefrom the peer port, 180 pass it to the bridge. */ 181 virtual void recvStatusChange(Status status); 182 183 /** When receiving a address range request the peer port, 184 pass it to the bridge. */ 185 virtual void getDeviceAddressRanges(AddrRangeList &resp, 186 bool &snoop); 187 }; 188 189 BridgePort portA, portB; 190 191 /** If this bridge should acknowledge writes. */ 192 bool ackWrites; 193 194 public: 195 typedef BridgeParams Params; 196 197 protected: 198 Params *_params; 199 200 public: 201 const Params *params() const { return _params; } 202 203 /** A function used to return the port associated with this bus object. */ 204 virtual Port *getPort(const std::string &if_name, int idx = -1); 205 206 virtual void init(); 207 208 Bridge(Params *p); 209}; 210 211#endif //__MEM_BUS_HH__ 212