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44 #ifndef __MEM_PACKET_QUEUE_HH__
45 #define __MEM_PACKET_QUEUE_HH__
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.
58 #include "mem/port.hh"
59 #include "sim/drain.hh"
60 #include "sim/eventq_impl.hh"
63 * A packet queue is a class that holds deferred packets and later
64 * sends them using the associated slave port or master port.
66 class PacketQueue : public Drainable
69 /** A deferred packet, buffered to transmit later. */
70 class DeferredPacket {
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)
80 typedef std::list<DeferredPacket> DeferredPacketList;
82 /** A list of outgoing timing response packets that haven't been
84 DeferredPacketList transmitList;
86 /** The manager which is used for the event queue */
89 /** This function attempts to send deferred packets. Scheduled to
90 * be called in the future via SendEvent. */
91 void processSendEvent();
94 * Event used to call processSendEvent.
96 EventWrapper<PacketQueue, &PacketQueue::processSendEvent> sendEvent;
98 /** If we need to drain, keep the drain manager around until we're done
100 DrainManager *drainManager;
104 /** Label to use for print request packets label stack. */
105 const std::string label;
107 /** Remember whether we're awaiting a retry from the bus. */
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(); }
114 Tick deferredPacketReadyTime() const
115 { return transmitList.empty() ? MaxTick : transmitList.front().tick; }
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).
124 virtual void sendDeferredPacket();
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
132 void trySendTiming();
137 virtual bool sendTiming(PacketPtr pkt, bool send_as_snoop) = 0;
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.
144 * @param time an alternative time for the next send event
146 void scheduleSend(Tick time = MaxTick);
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.
155 virtual void recvRangeChange() { }
158 * Create a packet queue, linked to an event manager, and a label
159 * that will be used for functional print request packets.
161 * @param _em Event manager used for scheduling this queue
162 * @param _label Label to push on the label stack for print request packets
164 PacketQueue(EventManager& _em, const std::string& _label);
167 * Virtual desctructor since the class may be used as a base class.
169 virtual ~PacketQueue();
174 * Provide a name to simplify debugging.
176 * @return A complete name, appended to module and port
178 virtual const std::string name() const = 0;
180 /** Check the list of buffered packets against the supplied
181 * functional request. */
182 bool checkFunctional(PacketPtr pkt);
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.
191 void schedSendEvent(Tick when);
194 * Add a packet to the transmit list, and ensure that a
195 * processSendEvent is called in the future.
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
201 void schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop = false);
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.
210 unsigned int drain(DrainManager *dm);
213 class MasterPacketQueue : public PacketQueue
218 MasterPort& masterPort;
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
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
231 MasterPacketQueue(EventManager& _em, MasterPort& _masterPort,
232 const std::string _label = "MasterPacketQueue");
234 virtual ~MasterPacketQueue() { }
236 const std::string name() const
237 { return masterPort.name() + "-" + label; }
239 bool sendTiming(PacketPtr pkt, bool send_as_snoop);
242 class SlavePacketQueue : public PacketQueue
247 SlavePort& slavePort;
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
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
260 SlavePacketQueue(EventManager& _em, SlavePort& _slavePort,
261 const std::string _label = "SlavePacketQueue");
263 virtual ~SlavePacketQueue() { }
265 const std::string name() const
266 { return slavePort.name() + "-" + label; }
268 bool sendTiming(PacketPtr pkt, bool send_as_snoop);
272 #endif // __MEM_PACKET_QUEUE_HH__