bridge.cc revision 2643:67ac7b611c56
1 2/* 3 * Copyright (c) 2006 The Regents of The University of Michigan 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are 8 * met: redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer; 10 * redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution; 13 * neither the name of the copyright holders nor the names of its 14 * contributors may be used to endorse or promote products derived from 15 * this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30/** 31 * @file Definition of a simple bus bridge without buffering. 32 */ 33 34#include <algorithm> 35 36#include "base/trace.hh" 37#include "mem/bridge.hh" 38#include "sim/builder.hh" 39 40Bridge::BridgePort::BridgePort(const std::string &_name, 41 Bridge *_bridge, BridgePort *_otherPort, 42 int _delay, int _queueLimit) 43 : Port(_name), bridge(_bridge), otherPort(_otherPort), 44 delay(_delay), outstandingResponses(0), 45 queueLimit(_queueLimit), sendEvent(this) 46{ 47} 48 49Bridge::Bridge(const std::string &n, int qsa, int qsb, 50 Tick _delay, int write_ack) 51 : MemObject(n), 52 portA(n + "-portA", this, &portB, _delay, qsa), 53 portB(n + "-portB", this, &portA, _delay, qsa), 54 ackWrites(write_ack) 55{ 56} 57 58Port * 59Bridge::getPort(const std::string &if_name) 60{ 61 BridgePort *port; 62 63 if (if_name == "side_a") 64 port = &portA; 65 else if (if_name == "side_b") 66 port = &portB; 67 else 68 return NULL; 69 70 if (port->getPeer() != NULL) 71 panic("bridge side %s already connected to.", if_name); 72 return port; 73} 74 75 76void 77Bridge::init() 78{ 79 // Make sure that both sides are connected to. 80 if (portA.getPeer() == NULL || portB.getPeer() == NULL) 81 panic("Both ports of bus bridge are not connected to a bus.\n"); 82} 83 84 85/** Function called by the port when the bus is receiving a Timing 86 * transaction.*/ 87bool 88Bridge::BridgePort::recvTiming(Packet *pkt) 89{ 90 DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n", 91 pkt->getSrc(), pkt->getDest(), pkt->getAddr()); 92 93 if (pkt->isResponse()) { 94 // This is a response for a request we forwarded earlier. The 95 // corresponding PacketBuffer should be stored in the packet's 96 // senderState field. 97 PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState); 98 assert(buf != NULL); 99 // set up new packet dest & senderState based on values saved 100 // from original request 101 buf->fixResponse(pkt); 102 DPRINTF(BusBridge, " is response, new dest %d\n", pkt->getDest()); 103 delete buf; 104 } 105 106 return otherPort->queueForSendTiming(pkt); 107} 108 109 110bool 111Bridge::BridgePort::queueForSendTiming(Packet *pkt) 112{ 113 if (queueFull()) 114 return false; 115 116 Tick readyTime = curTick + delay; 117 PacketBuffer *buf = new PacketBuffer(pkt, readyTime); 118 119 // If we're about to put this packet at the head of the queue, we 120 // need to schedule an event to do the transmit. Otherwise there 121 // should already be an event scheduled for sending the head 122 // packet. 123 if (sendQueue.empty()) { 124 sendEvent.schedule(readyTime); 125 } 126 127 sendQueue.push_back(buf); 128 129 // Did we just become blocked? If yes, let other side know. 130 if (queueFull()) 131 otherPort->sendStatusChange(Port::Blocked); 132 133 return true; 134} 135 136 137void 138Bridge::BridgePort::finishSend(PacketBuffer *buf) 139{ 140 if (buf->expectResponse) { 141 // Must wait for response. We just need to count outstanding 142 // responses (in case we want to cap them); PacketBuffer 143 // pointer will be recovered on response. 144 ++outstandingResponses; 145 DPRINTF(BusBridge, " successful: awaiting response (%d)\n", 146 outstandingResponses); 147 } else { 148 // no response expected... deallocate packet buffer now. 149 DPRINTF(BusBridge, " successful: no response expected\n"); 150 delete buf; 151 } 152 153 // If there are more packets to send, schedule event to try again. 154 if (!sendQueue.empty()) { 155 buf = sendQueue.front(); 156 sendEvent.schedule(std::max(buf->ready, curTick + 1)); 157 } 158} 159 160 161void 162Bridge::BridgePort::trySend() 163{ 164 assert(!sendQueue.empty()); 165 166 PacketBuffer *buf = sendQueue.front(); 167 168 assert(buf->ready <= curTick); 169 170 Packet *pkt = buf->pkt; 171 172 DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n", 173 buf->origSrc, pkt->getDest(), pkt->getAddr()); 174 175 if (sendTiming(pkt)) { 176 // send successful 177 sendQueue.pop_front(); 178 buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it 179 finishSend(buf); 180 } else { 181 DPRINTF(BusBridge, " unsuccessful\n"); 182 } 183} 184 185 186Packet * 187Bridge::BridgePort::recvRetry() 188{ 189 PacketBuffer *buf = sendQueue.front(); 190 Packet *pkt = buf->pkt; 191 finishSend(buf); 192 return pkt; 193} 194 195/** Function called by the port when the bus is receiving a Atomic 196 * transaction.*/ 197Tick 198Bridge::BridgePort::recvAtomic(Packet *pkt) 199{ 200 return otherPort->sendAtomic(pkt) + delay; 201} 202 203/** Function called by the port when the bus is receiving a Functional 204 * transaction.*/ 205void 206Bridge::BridgePort::recvFunctional(Packet *pkt) 207{ 208 std::list<PacketBuffer*>::iterator i; 209 bool pktContinue = true; 210 211 for (i = sendQueue.begin(); i != sendQueue.end(); ++i) { 212 if (pkt->intersect((*i)->pkt)) { 213 pktContinue &= fixPacket(pkt, (*i)->pkt); 214 } 215 } 216 217 if (pktContinue) { 218 otherPort->sendFunctional(pkt); 219 } 220} 221 222/** Function called by the port when the bus is receiving a status change.*/ 223void 224Bridge::BridgePort::recvStatusChange(Port::Status status) 225{ 226 if (status == Port::Blocked || status == Port::Unblocked) 227 return; 228 229 otherPort->sendStatusChange(status); 230} 231 232void 233Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp, 234 AddrRangeList &snoop) 235{ 236 otherPort->getPeerAddressRanges(resp, snoop); 237} 238 239BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge) 240 241 Param<int> queue_size_a; 242 Param<int> queue_size_b; 243 Param<Tick> delay; 244 Param<bool> write_ack; 245 246END_DECLARE_SIM_OBJECT_PARAMS(Bridge) 247 248BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge) 249 250 INIT_PARAM(queue_size_a, "The size of the queue for data coming into side a"), 251 INIT_PARAM(queue_size_b, "The size of the queue for data coming into side b"), 252 INIT_PARAM(delay, "The miminum delay to cross this bridge"), 253 INIT_PARAM(write_ack, "Acknowledge any writes that are received.") 254 255END_INIT_SIM_OBJECT_PARAMS(Bridge) 256 257CREATE_SIM_OBJECT(Bridge) 258{ 259 return new Bridge(getInstanceName(), queue_size_a, queue_size_b, delay, 260 write_ack); 261} 262 263REGISTER_SIM_OBJECT("Bridge", Bridge) 264