tport.cc revision 4493:0757d7c8a0e5
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 */ 30 31#include "mem/tport.hh" 32 33void 34SimpleTimingPort::checkFunctional(PacketPtr pkt) 35{ 36 DeferredPacketIterator i = transmitList.begin(); 37 DeferredPacketIterator end = transmitList.end(); 38 39 for (; i != end; ++i) { 40 PacketPtr target = i->pkt; 41 // If the target contains data, and it overlaps the 42 // probed request, need to update data 43 if (target->intersect(pkt)) { 44 if (!fixPacket(pkt, target)) { 45 // fixPacket returns true for continue, false for done 46 return; 47 } 48 } 49 } 50} 51 52void 53SimpleTimingPort::recvFunctional(PacketPtr pkt) 54{ 55 checkFunctional(pkt); 56 57 // Just do an atomic access and throw away the returned latency 58 if (pkt->result != Packet::Success) 59 recvAtomic(pkt); 60} 61 62bool 63SimpleTimingPort::recvTiming(PacketPtr pkt) 64{ 65 // If the device is only a slave, it should only be sending 66 // responses, which should never get nacked. There used to be 67 // code to hanldle nacks here, but I'm pretty sure it didn't work 68 // correctly with the drain code, so that would need to be fixed 69 // if we ever added it back. 70 assert(pkt->result != Packet::Nacked); 71 Tick latency = recvAtomic(pkt); 72 // turn packet around to go back to requester if response expected 73 if (pkt->needsResponse()) { 74 pkt->makeTimingResponse(); 75 schedSendTiming(pkt, curTick + latency); 76 } 77 else if (pkt->cmd != MemCmd::UpgradeReq) { 78 delete pkt->req; 79 delete pkt; 80 } 81 return true; 82} 83 84 85void 86SimpleTimingPort::schedSendTiming(PacketPtr pkt, Tick when) 87{ 88 assert(when > curTick); 89 90 // Nothing is on the list: add it and schedule an event 91 if (transmitList.empty()) { 92 assert(!sendEvent->scheduled()); 93 sendEvent->schedule(when); 94 transmitList.push_back(DeferredPacket(when, pkt)); 95 return; 96 } 97 98 // something is on the list and this belongs at the end 99 if (when >= transmitList.back().tick) { 100 transmitList.push_back(DeferredPacket(when, pkt)); 101 return; 102 } 103 // Something is on the list and this belongs somewhere else 104 DeferredPacketIterator i = transmitList.begin(); 105 DeferredPacketIterator end = transmitList.end(); 106 107 for (; i != end; ++i) { 108 if (when < i->tick) { 109 if (i == transmitList.begin()) { 110 //Inserting at begining, reschedule 111 sendEvent->reschedule(when); 112 } 113 transmitList.insert(i, DeferredPacket(when, pkt)); 114 return; 115 } 116 } 117 assert(false); // should never get here 118} 119 120 121void 122SimpleTimingPort::sendDeferredPacket() 123{ 124 assert(deferredPacketReady()); 125 bool success = sendTiming(transmitList.front().pkt); 126 127 if (success) { 128 //send successful, remove packet 129 transmitList.pop_front(); 130 if (!transmitList.empty()) { 131 Tick time = transmitList.front().tick; 132 sendEvent->schedule(time <= curTick ? curTick+1 : time); 133 } 134 135 if (transmitList.empty() && drainEvent) { 136 drainEvent->process(); 137 drainEvent = NULL; 138 } 139 } 140 141 waitingOnRetry = !success; 142 143 if (waitingOnRetry) { 144 DPRINTF(Bus, "Send failed, waiting on retry\n"); 145 } 146} 147 148 149void 150SimpleTimingPort::recvRetry() 151{ 152 DPRINTF(Bus, "Received retry\n"); 153 assert(waitingOnRetry); 154 sendDeferredPacket(); 155} 156 157 158void 159SimpleTimingPort::processSendEvent() 160{ 161 assert(!waitingOnRetry); 162 sendDeferredPacket(); 163} 164 165 166unsigned int 167SimpleTimingPort::drain(Event *de) 168{ 169 if (transmitList.size() == 0) 170 return 0; 171 drainEvent = de; 172 return 1; 173} 174