packet_queue.hh revision 8711
12SN/A/* 21762SN/A * Copyright (c) 2006 The Regents of The University of Michigan 32SN/A * All rights reserved. 42SN/A * 52SN/A * Redistribution and use in source and binary forms, with or without 62SN/A * modification, are permitted provided that the following conditions are 72SN/A * met: redistributions of source code must retain the above copyright 82SN/A * notice, this list of conditions and the following disclaimer; 92SN/A * redistributions in binary form must reproduce the above copyright 102SN/A * notice, this list of conditions and the following disclaimer in the 112SN/A * documentation and/or other materials provided with the distribution; 122SN/A * neither the name of the copyright holders nor the names of its 132SN/A * contributors may be used to endorse or promote products derived from 142SN/A * this software without specific prior written permission. 152SN/A * 162SN/A * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 172SN/A * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 182SN/A * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 192SN/A * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 202SN/A * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 212SN/A * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 222SN/A * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 232SN/A * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 242SN/A * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 252SN/A * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 262SN/A * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 272665Ssaidi@eecs.umich.edu * 282665Ssaidi@eecs.umich.edu * Authors: Ali Saidi 292665Ssaidi@eecs.umich.edu */ 302SN/A 312SN/A#ifndef __MEM_TPORT_HH__ 321717SN/A#define __MEM_TPORT_HH__ 331717SN/A 342SN/A/** 352SN/A * @file 362SN/A * 37707SN/A * Declaration of SimpleTimingPort. 381858SN/A */ 3956SN/A 402856Srdreslin@umich.edu#include <list> 412109SN/A#include <string> 422SN/A 432190SN/A#include "mem/port.hh" 442315SN/A#include "sim/eventq.hh" 452680Sktlim@umich.edu 462SN/A/** 472856Srdreslin@umich.edu * A simple port for interfacing objects that basically have only 482SN/A * functional memory behavior (e.g. I/O devices) to the memory system. 492356SN/A * Both timing and functional accesses are implemented in terms of 502356SN/A * atomic accesses. A derived port class thus only needs to provide 512356SN/A * recvAtomic() to support all memory access modes. 522356SN/A * 532356SN/A * The tricky part is handling recvTiming(), where the response must 542356SN/A * be scheduled separately via a later call to sendTiming(). This 552356SN/A * feature is handled by scheduling an internal event that calls 562356SN/A * sendTiming() after a delay, and optionally rescheduling the 573126Sktlim@umich.edu * response if it is nacked. 582356SN/A */ 592356SN/Aclass SimpleTimingPort : public Port 602356SN/A{ 612356SN/A protected: 622356SN/A /** A deferred packet, buffered to transmit later. */ 632356SN/A class DeferredPacket { 642856Srdreslin@umich.edu public: 652SN/A Tick tick; ///< The tick when the packet is ready to transmit 661634SN/A PacketPtr pkt; ///< Pointer to the packet to transmit 671634SN/A DeferredPacket(Tick t, PacketPtr p) 681695SN/A : tick(t), pkt(p) 691634SN/A {} 701634SN/A }; 712359SN/A 721695SN/A typedef std::list<DeferredPacket> DeferredPacketList; 731695SN/A typedef std::list<DeferredPacket>::iterator DeferredPacketIterator; 741695SN/A 751634SN/A /** A list of outgoing timing response packets that haven't been 761858SN/A * serviced yet. */ 772SN/A DeferredPacketList transmitList; 782107SN/A 792SN/A /** This function attempts to send deferred packets. Scheduled to 802SN/A * be called in the future via SendEvent. */ 812SN/A void processSendEvent(); 822SN/A 832SN/A /** 842SN/A * This class is used to implemented sendTiming() with a delay. When 851133SN/A * a delay is requested a the event is scheduled if it isn't already. 862SN/A * When the event time expires it attempts to send the packet. 872SN/A * If it cannot, the packet sent when recvRetry() is called. 882107SN/A **/ 892SN/A Event *sendEvent; 902SN/A 912SN/A /** If we need to drain, keep the drain event around until we're done 922SN/A * here.*/ 932SN/A Event *drainEvent; 942SN/A 952SN/A /** Remember whether we're awaiting a retry from the bus. */ 961917SN/A bool waitingOnRetry; 971917SN/A 981917SN/A /** Check the list of buffered packets against the supplied 991917SN/A * functional request. */ 1001917SN/A bool checkFunctional(PacketPtr funcPkt); 1011917SN/A 1021917SN/A /** Check whether we have a packet ready to go on the transmit list. */ 1031917SN/A bool deferredPacketReady() 1041917SN/A { return !transmitList.empty() && transmitList.front().tick <= curTick(); } 1051917SN/A 1061917SN/A Tick deferredPacketReadyTime() 1071917SN/A { return transmitList.empty() ? MaxTick : transmitList.front().tick; } 1082SN/A 1092SN/A /** 1102SN/A * Schedule a send even if not already waiting for a retry. If the 1112680Sktlim@umich.edu * requested time is before an already scheduled send event it 1122SN/A * will be rescheduled. 1132SN/A * 114393SN/A * @param when 115393SN/A */ 116393SN/A void schedSendEvent(Tick when); 117393SN/A 118393SN/A /** Schedule a sendTiming() event to be called in the future. 119393SN/A * @param pkt packet to send 120393SN/A * @param absolute time (in ticks) to send packet 121393SN/A */ 122393SN/A void schedSendTiming(PacketPtr pkt, Tick when); 123393SN/A 124393SN/A /** Attempt to send the packet at the head of the deferred packet 125393SN/A * list. Caller must guarantee that the deferred packet list is 126393SN/A * non-empty and that the head packet is scheduled for curTick() (or 127393SN/A * earlier). 1282SN/A */ 1292SN/A void sendDeferredPacket(); 1301400SN/A 1311400SN/A /** This function is notification that the device should attempt to send a 1321400SN/A * packet again. */ 1331400SN/A virtual void recvRetry(); 1341400SN/A 1351400SN/A /** Implemented using recvAtomic(). */ 1361400SN/A void recvFunctional(PacketPtr pkt); 1371400SN/A 1381400SN/A /** Implemented using recvAtomic(). */ 1391695SN/A bool recvTiming(PacketPtr pkt); 1401400SN/A 1411400SN/A /** 1422378SN/A * Simple ports are generally used as slave ports (i.e. the 1433170Sstever@eecs.umich.edu * respond to requests) and thus do not expect to receive any 1441858SN/A * range changes (as the neighbouring port has a master role and 1451917SN/A * do not have any address ranges. A subclass can override the 1461400SN/A * default behaviuor if needed. 1472356SN/A */ 1482315SN/A virtual void recvRangeChange() { } 1491917SN/A 1501917SN/A 1511400SN/A public: 1522SN/A SimpleTimingPort(std::string pname, MemObject *_owner); 1531400SN/A ~SimpleTimingPort(); 1542SN/A 1551400SN/A /** Hook for draining timing accesses from the system. The 1561191SN/A * associated SimObject's drain() functions should be implemented 1572SN/A * something like this when this class is used: 1581129SN/A \code 1591917SN/A PioDevice::drain(Event *de) 1602SN/A { 1612SN/A unsigned int count; 1622103SN/A count = SimpleTimingPort->drain(de); 1632103SN/A if (count) 1642680Sktlim@umich.edu changeState(Draining); 165180SN/A else 1661492SN/A changeState(Drained); 1671492SN/A return count; 1682798Sktlim@umich.edu } 169180SN/A \endcode 170180SN/A */ 171180SN/A unsigned int drain(Event *de); 172180SN/A}; 173180SN/A 174124SN/A#endif // __MEM_TPORT_HH__ 175124SN/A