packet_queue.hh revision 10713
1/* 2 * Copyright (c) 2012,2015 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. 53 */ 54 55#include <list> 56 57#include "mem/port.hh" 58#include "sim/drain.hh" 59#include "sim/eventq_impl.hh" 60 61/** 62 * A packet queue is a class that holds deferred packets and later 63 * sends them using the associated slave port or master port. 64 */ 65class PacketQueue : public Drainable 66{ 67 private: 68 /** A deferred packet, buffered to transmit later. */ 69 class DeferredPacket { 70 public: 71 Tick tick; ///< The tick when the packet is ready to transmit 72 PacketPtr pkt; ///< Pointer to the packet to transmit 73 DeferredPacket(Tick t, PacketPtr p) 74 : tick(t), pkt(p) 75 {} 76 }; 77 78 typedef std::list<DeferredPacket> DeferredPacketList; 79 80 /** A list of outgoing packets. */ 81 DeferredPacketList transmitList; 82 83 /** The manager which is used for the event queue */ 84 EventManager& em; 85 86 /** Used to schedule sending of deferred packets. */ 87 void processSendEvent(); 88 89 /** Event used to call processSendEvent. */ 90 EventWrapper<PacketQueue, &PacketQueue::processSendEvent> sendEvent; 91 92 /** If we need to drain, keep the drain manager around until we're done 93 * here.*/ 94 DrainManager *drainManager; 95 96 protected: 97 98 /** Label to use for print request packets label stack. */ 99 const std::string label; 100 101 /** Remember whether we're awaiting a retry. */ 102 bool waitingOnRetry; 103 104 /** Check whether we have a packet ready to go on the transmit list. */ 105 bool deferredPacketReady() const 106 { return !transmitList.empty() && transmitList.front().tick <= curTick(); } 107 108 /** 109 * Attempt to send a packet. Note that a subclass of the 110 * PacketQueue can override this method and thus change the 111 * behaviour (as done by the cache for the request queue). The 112 * default implementation sends the head of the transmit list. The 113 * caller must guarantee that the list is non-empty and that the 114 * head packet is scheduled for curTick() (or earlier). 115 */ 116 virtual void sendDeferredPacket(); 117 118 /** 119 * Send a packet using the appropriate method for the specific 120 * subclass (reuest, response or snoop response). 121 */ 122 virtual bool sendTiming(PacketPtr pkt) = 0; 123 124 /** 125 * Create a packet queue, linked to an event manager, and a label 126 * that will be used for functional print request packets. 127 * 128 * @param _em Event manager used for scheduling this queue 129 * @param _label Label to push on the label stack for print request packets 130 */ 131 PacketQueue(EventManager& _em, const std::string& _label); 132 133 /** 134 * Virtual desctructor since the class may be used as a base class. 135 */ 136 virtual ~PacketQueue(); 137 138 public: 139 140 /** 141 * Provide a name to simplify debugging. 142 * 143 * @return A complete name, appended to module and port 144 */ 145 virtual const std::string name() const = 0; 146 147 /** 148 * Get the size of the queue. 149 */ 150 size_t size() const { return transmitList.size(); } 151 152 /** 153 * Get the next packet ready time. 154 */ 155 Tick deferredPacketReadyTime() const 156 { return transmitList.empty() ? MaxTick : transmitList.front().tick; } 157 158 /** 159 * Check if a packets address exists in the queue. 160 */ 161 bool hasAddr(Addr addr) const; 162 163 /** Check the list of buffered packets against the supplied 164 * functional request. */ 165 bool checkFunctional(PacketPtr pkt); 166 167 /** 168 * Schedule a send event if we are not already waiting for a 169 * retry. If the requested time is before an already scheduled 170 * send event, the event will be rescheduled. If MaxTick is 171 * passed, no event is scheduled. Instead, if we are idle and 172 * asked to drain then check and signal drained. 173 * 174 * @param when time to schedule an event 175 */ 176 void schedSendEvent(Tick when); 177 178 /** 179 * Add a packet to the transmit list, and schedule a send event. 180 * 181 * @param pkt Packet to send 182 * @param when Absolute time (in ticks) to send packet 183 */ 184 void schedSendTiming(PacketPtr pkt, Tick when); 185 186 /** 187 * Retry sending a packet from the queue. Note that this is not 188 * necessarily the same packet if something has been added with an 189 * earlier time stamp. 190 */ 191 void retry(); 192 193 unsigned int drain(DrainManager *dm); 194}; 195 196class ReqPacketQueue : public PacketQueue 197{ 198 199 protected: 200 201 MasterPort& masterPort; 202 203 public: 204 205 /** 206 * Create a request packet queue, linked to an event manager, a 207 * master port, and a label that will be used for functional print 208 * request packets. 209 * 210 * @param _em Event manager used for scheduling this queue 211 * @param _masterPort Master port used to send the packets 212 * @param _label Label to push on the label stack for print request packets 213 */ 214 ReqPacketQueue(EventManager& _em, MasterPort& _masterPort, 215 const std::string _label = "ReqPacketQueue"); 216 217 virtual ~ReqPacketQueue() { } 218 219 const std::string name() const 220 { return masterPort.name() + "-" + label; } 221 222 bool sendTiming(PacketPtr pkt); 223 224}; 225 226class SnoopRespPacketQueue : public PacketQueue 227{ 228 229 protected: 230 231 MasterPort& masterPort; 232 233 public: 234 235 /** 236 * Create a snoop response packet queue, linked to an event 237 * manager, a master port, and a label that will be used for 238 * functional print request packets. 239 * 240 * @param _em Event manager used for scheduling this queue 241 * @param _masterPort Master port used to send the packets 242 * @param _label Label to push on the label stack for print request packets 243 */ 244 SnoopRespPacketQueue(EventManager& _em, MasterPort& _masterPort, 245 const std::string _label = "SnoopRespPacketQueue"); 246 247 virtual ~SnoopRespPacketQueue() { } 248 249 const std::string name() const 250 { return masterPort.name() + "-" + label; } 251 252 bool sendTiming(PacketPtr pkt); 253 254}; 255 256class RespPacketQueue : public PacketQueue 257{ 258 259 protected: 260 261 SlavePort& slavePort; 262 263 public: 264 265 /** 266 * Create a response packet queue, linked to an event manager, a 267 * slave port, and a label that will be used for functional print 268 * request packets. 269 * 270 * @param _em Event manager used for scheduling this queue 271 * @param _slavePort Slave port used to send the packets 272 * @param _label Label to push on the label stack for print request packets 273 */ 274 RespPacketQueue(EventManager& _em, SlavePort& _slavePort, 275 const std::string _label = "RespPacketQueue"); 276 277 virtual ~RespPacketQueue() { } 278 279 const std::string name() const 280 { return slavePort.name() + "-" + label; } 281 282 bool sendTiming(PacketPtr pkt); 283 284}; 285 286#endif // __MEM_PACKET_QUEUE_HH__ 287