tport.hh revision 2914
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/** 32 * @file 33 * Implement a port which adds simple support of a sendTiming() function that 34 * takes a delay. In this way the * device can immediatly call 35 * sendTiming(pkt, time) after processing a request and the request will be 36 * handled by the port even if the port bus the device connects to is blocked. 37 */ 38 39/** recvTiming and drain should be implemented something like this when this 40 * class is used. 41 42bool 43PioPort::recvTiming(Packet *pkt) 44{ 45 if (pkt->result == Packet::Nacked) { 46 resendNacked(pkt); 47 } else { 48 Tick latency = device->recvAtomic(pkt); 49 // turn packet around to go back to requester 50 pkt->makeTimingResponse(); 51 sendTiming(pkt, latency); 52 } 53 return true; 54} 55 56PioDevice::drain(Event *de) 57{ 58 unsigned int count; 59 count = SimpleTimingPort->drain(de); 60 if (count) 61 changeState(Draining); 62 else 63 changeState(Drained); 64 return count; 65} 66*/ 67 68#ifndef __MEM_TPORT_HH__ 69#define __MEM_TPORT_HH__ 70 71#include "mem/port.hh" 72#include "sim/eventq.hh" 73#include <list> 74#include <string> 75 76class SimpleTimingPort : public Port 77{ 78 protected: 79 /** A list of outgoing timing response packets that haven't been serviced 80 * yet. */ 81 std::list<Packet*> transmitList; 82 /** 83 * This class is used to implemented sendTiming() with a delay. When a delay 84 * is requested a new event is created. When the event time expires it 85 * attempts to send the packet. If it cannot, the packet is pushed onto the 86 * transmit list to be sent when recvRetry() is called. */ 87 class SendEvent : public Event 88 { 89 SimpleTimingPort *port; 90 Packet *packet; 91 92 SendEvent(SimpleTimingPort *p, Packet *pkt, Tick t) 93 : Event(&mainEventQueue), port(p), packet(pkt) 94 { setFlags(AutoDelete); schedule(curTick + t); } 95 96 virtual void process(); 97 98 virtual const char *description() 99 { return "Future scheduled sendTiming event"; } 100 101 friend class SimpleTimingPort; 102 }; 103 104 105 /** Number of timing requests that are emulating the device timing before 106 * attempting to end up on the bus. 107 */ 108 int outTiming; 109 110 /** If we need to drain, keep the drain event around until we're done 111 * here.*/ 112 Event *drainEvent; 113 114 /** Schedule a sendTiming() event to be called in the future. */ 115 void sendTiming(Packet *pkt, Tick time) 116 { outTiming++; new SimpleTimingPort::SendEvent(this, pkt, time); } 117 118 /** This function is notification that the device should attempt to send a 119 * packet again. */ 120 virtual void recvRetry(); 121 122 void resendNacked(Packet *pkt); 123 public: 124 125 SimpleTimingPort(std::string pname) 126 : Port(pname), outTiming(0), drainEvent(NULL) 127 {} 128 129 unsigned int drain(Event *de); 130 131 friend class SimpleTimingPort::SendEvent; 132}; 133 134#endif // __MEM_TPORT_HH__ 135