packet_queue.cc revision 3296
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::recvFunctional(Packet *pkt) 35{ 36 //First check queued events 37 std::list<Packet *>::iterator i = transmitList.begin(); 38 std::list<Packet *>::iterator end = transmitList.end(); 39 bool cont = true; 40 41 while (i != end && cont) { 42 Packet * target = *i; 43 // If the target contains data, and it overlaps the 44 // probed request, need to update data 45 if (target->intersect(pkt)) 46 fixPacket(pkt, target); 47 48 } 49 //Then just do an atomic access and throw away the returned latency 50 if (cont) 51 recvAtomic(pkt); 52} 53 54bool 55SimpleTimingPort::recvTiming(Packet *pkt) 56{ 57 // If the device is only a slave, it should only be sending 58 // responses, which should never get nacked. There used to be 59 // code to hanldle nacks here, but I'm pretty sure it didn't work 60 // correctly with the drain code, so that would need to be fixed 61 // if we ever added it back. 62 assert(pkt->result != Packet::Nacked); 63 Tick latency = recvAtomic(pkt); 64 // turn packet around to go back to requester if response expected 65 if (pkt->needsResponse()) { 66 pkt->makeTimingResponse(); 67 sendTimingLater(pkt, latency); 68 } 69 return true; 70} 71 72void 73SimpleTimingPort::recvRetry() 74{ 75 assert(outTiming > 0); 76 assert(!transmitList.empty()); 77 if (sendTiming(transmitList.front())) { 78 transmitList.pop_front(); 79 outTiming--; 80 DPRINTF(Bus, "No Longer waiting on retry\n"); 81 if (!transmitList.empty()) 82 sendTimingLater(transmitList.front(), 1); 83 } 84 85 if (transmitList.empty() && drainEvent) { 86 drainEvent->process(); 87 drainEvent = NULL; 88 } 89} 90 91void 92SimpleTimingPort::SendEvent::process() 93{ 94 assert(port->outTiming > 0); 95 if (!port->transmitList.empty() && port->transmitList.front() != packet) { 96 //We are not the head of the list 97 port->transmitList.push_back(packet); 98 } else if (port->sendTiming(packet)) { 99 // send successful 100 if (port->transmitList.size()) { 101 port->transmitList.pop_front(); 102 port->outTiming--; 103 if (!port->transmitList.empty()) 104 port->sendTimingLater(port->transmitList.front(), 1); 105 } 106 if (port->transmitList.empty() && port->drainEvent) { 107 port->drainEvent->process(); 108 port->drainEvent = NULL; 109 } 110 } else { 111 // send unsuccessful (due to flow control). Will get retry 112 // callback later; save for then if not already 113 DPRINTF(Bus, "Waiting on retry\n"); 114 if (!(port->transmitList.front() == packet)) 115 port->transmitList.push_back(packet); 116 } 117} 118 119 120unsigned int 121SimpleTimingPort::drain(Event *de) 122{ 123 if (outTiming == 0 && transmitList.size() == 0) 124 return 0; 125 drainEvent = de; 126 return 1; 127} 128