tport.cc revision 3175
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 // just do an atomic access and throw away the returned latency 37 recvAtomic(pkt); 38} 39 40bool 41SimpleTimingPort::recvTiming(Packet *pkt) 42{ 43 // If the device is only a slave, it should only be sending 44 // responses, which should never get nacked. There used to be 45 // code to hanldle nacks here, but I'm pretty sure it didn't work 46 // correctly with the drain code, so that would need to be fixed 47 // if we ever added it back. 48 assert(pkt->result != Packet::Nacked); 49 Tick latency = recvAtomic(pkt); 50 // turn packet around to go back to requester if response expected 51 if (pkt->needsResponse()) { 52 pkt->makeTimingResponse(); 53 sendTimingLater(pkt, latency); 54 } 55 return true; 56} 57 58void 59SimpleTimingPort::recvRetry() 60{ 61 bool result = true; 62 while (result && transmitList.size()) { 63 result = sendTiming(transmitList.front()); 64 if (result) 65 transmitList.pop_front(); 66 } 67 if (transmitList.size() == 0 && drainEvent) { 68 drainEvent->process(); 69 drainEvent = NULL; 70 } 71} 72 73void 74SimpleTimingPort::SendEvent::process() 75{ 76 port->outTiming--; 77 assert(port->outTiming >= 0); 78 if (port->sendTiming(packet)) { 79 // send successfule 80 if (port->transmitList.size() == 0 && port->drainEvent) { 81 port->drainEvent->process(); 82 port->drainEvent = NULL; 83 } 84 } else { 85 // send unsuccessful (due to flow control). Will get retry 86 // callback later; save for then. 87 port->transmitList.push_back(packet); 88 } 89} 90 91 92unsigned int 93SimpleTimingPort::drain(Event *de) 94{ 95 if (outTiming == 0 && transmitList.size() == 0) 96 return 0; 97 drainEvent = de; 98 return 1; 99} 100