packet_queue.hh revision 10322:7f4059e4f2d5
1/* 2 * Copyright (c) 2012 ARM Limited 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2006 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Ali Saidi 41 * Andreas Hansson 42 */ 43 44#ifndef __MEM_PACKET_QUEUE_HH__ 45#define __MEM_PACKET_QUEUE_HH__ 46 47/** 48 * @file 49 * Declaration of a simple PacketQueue that is associated with 50 * a port on which it attempts to send packets according to the time 51 * stamp given to them at insertion. The packet queue is responsible 52 * for the flow control of the port, but relies on the module 53 * notifying the queue when a transfer ends. 54 */ 55 56#include <list> 57 58#include "mem/port.hh" 59#include "sim/drain.hh" 60#include "sim/eventq_impl.hh" 61 62/** 63 * A packet queue is a class that holds deferred packets and later 64 * sends them using the associated slave port or master port. 65 */ 66class PacketQueue : public Drainable 67{ 68 private: 69 /** A deferred packet, buffered to transmit later. */ 70 class DeferredPacket { 71 public: 72 Tick tick; ///< The tick when the packet is ready to transmit 73 PacketPtr pkt; ///< Pointer to the packet to transmit 74 bool sendAsSnoop; ///< Should it be sent as a snoop or not 75 DeferredPacket(Tick t, PacketPtr p, bool send_as_snoop) 76 : tick(t), pkt(p), sendAsSnoop(send_as_snoop) 77 {} 78 }; 79 80 typedef std::list<DeferredPacket> DeferredPacketList; 81 82 /** A list of outgoing timing response packets that haven't been 83 * serviced yet. */ 84 DeferredPacketList transmitList; 85 86 /** The manager which is used for the event queue */ 87 EventManager& em; 88 89 /** This function attempts to send deferred packets. Scheduled to 90 * be called in the future via SendEvent. */ 91 void processSendEvent(); 92 93 /** 94 * Event used to call processSendEvent. 95 **/ 96 EventWrapper<PacketQueue, &PacketQueue::processSendEvent> sendEvent; 97 98 /** If we need to drain, keep the drain manager around until we're done 99 * here.*/ 100 DrainManager *drainManager; 101 102 protected: 103 104 /** Label to use for print request packets label stack. */ 105 const std::string label; 106 107 /** Remember whether we're awaiting a retry from the bus. */ 108 bool waitingOnRetry; 109 110 /** Check whether we have a packet ready to go on the transmit list. */ 111 bool deferredPacketReady() const 112 { return !transmitList.empty() && transmitList.front().tick <= curTick(); } 113 114 Tick deferredPacketReadyTime() const 115 { return transmitList.empty() ? MaxTick : transmitList.front().tick; } 116 117 /** 118 * Attempt to send the packet at the head of the transmit 119 * list. Caller must guarantee that the list is non-empty and that 120 * the head packet is scheduled for curTick() (or earlier). Note 121 * that a subclass of the PacketQueue can override this method and 122 * thus change the behaviour (as done by the cache). 123 */ 124 virtual void sendDeferredPacket(); 125 126 /** 127 * Attempt to send the packet at the front of the transmit list, 128 * and set waitingOnRetry accordingly. The packet is temporarily 129 * taken off the list, but put back at the front if not 130 * successfully sent. 131 */ 132 void trySendTiming(); 133 134 /** 135 * 136 */ 137 virtual bool sendTiming(PacketPtr pkt, bool send_as_snoop) = 0; 138 139 /** 140 * Based on the transmit list, or the provided time, schedule a 141 * send event if there are packets to send. If we are idle and 142 * asked to drain then do so. 143 * 144 * @param time an alternative time for the next send event 145 */ 146 void scheduleSend(Tick time = MaxTick); 147 148 /** 149 * Simple ports are generally used as slave ports (i.e. the 150 * respond to requests) and thus do not expect to receive any 151 * range changes (as the neighbouring port has a master role and 152 * do not have any address ranges. A subclass can override the 153 * default behaviuor if needed. 154 */ 155 virtual void recvRangeChange() { } 156 157 /** 158 * Create a packet queue, linked to an event manager, and a label 159 * that will be used for functional print request packets. 160 * 161 * @param _em Event manager used for scheduling this queue 162 * @param _label Label to push on the label stack for print request packets 163 */ 164 PacketQueue(EventManager& _em, const std::string& _label); 165 166 /** 167 * Virtual desctructor since the class may be used as a base class. 168 */ 169 virtual ~PacketQueue(); 170 171 public: 172 173 /** 174 * Provide a name to simplify debugging. 175 * 176 * @return A complete name, appended to module and port 177 */ 178 virtual const std::string name() const = 0; 179 180 /** Check the list of buffered packets against the supplied 181 * functional request. */ 182 bool checkFunctional(PacketPtr pkt); 183 184 /** 185 * Schedule a send even if not already waiting for a retry. If the 186 * requested time is before an already scheduled send event it 187 * will be rescheduled. 188 * 189 * @param when 190 */ 191 void schedSendEvent(Tick when); 192 193 /** 194 * Add a packet to the transmit list, and ensure that a 195 * processSendEvent is called in the future. 196 * 197 * @param pkt Packet to send 198 * @param when Absolute time (in ticks) to send packet 199 * @param send_as_snoop Send the packet as a snoop or not 200 */ 201 void schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop = false); 202 203 /** 204 * Used by a port to notify the queue that a retry was received 205 * and that the queue can proceed and retry sending the packet 206 * that caused the wait. 207 */ 208 void retry(); 209 210 unsigned int drain(DrainManager *dm); 211}; 212 213class MasterPacketQueue : public PacketQueue 214{ 215 216 protected: 217 218 MasterPort& masterPort; 219 220 public: 221 222 /** 223 * Create a master packet queue, linked to an event manager, a 224 * master port, and a label that will be used for functional print 225 * request packets. 226 * 227 * @param _em Event manager used for scheduling this queue 228 * @param _masterPort Master port used to send the packets 229 * @param _label Label to push on the label stack for print request packets 230 */ 231 MasterPacketQueue(EventManager& _em, MasterPort& _masterPort, 232 const std::string _label = "MasterPacketQueue"); 233 234 virtual ~MasterPacketQueue() { } 235 236 const std::string name() const 237 { return masterPort.name() + "-" + label; } 238 239 bool sendTiming(PacketPtr pkt, bool send_as_snoop); 240}; 241 242class SlavePacketQueue : public PacketQueue 243{ 244 245 protected: 246 247 SlavePort& slavePort; 248 249 public: 250 251 /** 252 * Create a slave packet queue, linked to an event manager, a 253 * slave port, and a label that will be used for functional print 254 * request packets. 255 * 256 * @param _em Event manager used for scheduling this queue 257 * @param _slavePort Slave port used to send the packets 258 * @param _label Label to push on the label stack for print request packets 259 */ 260 SlavePacketQueue(EventManager& _em, SlavePort& _slavePort, 261 const std::string _label = "SlavePacketQueue"); 262 263 virtual ~SlavePacketQueue() { } 264 265 const std::string name() const 266 { return slavePort.name() + "-" + label; } 267 268 bool sendTiming(PacketPtr pkt, bool send_as_snoop); 269 270}; 271 272#endif // __MEM_PACKET_QUEUE_HH__ 273