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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.
57 #include "mem/port.hh"
58 #include "sim/drain.hh"
59 #include "sim/eventq_impl.hh"
62 * A packet queue is a class that holds deferred packets and later
63 * sends them using the associated slave port or master port.
65 class PacketQueue : public Drainable
68 /** A deferred packet, buffered to transmit later. */
69 class DeferredPacket {
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)
78 typedef std::list<DeferredPacket> DeferredPacketList;
80 /** A list of outgoing packets. */
81 DeferredPacketList transmitList;
83 /** The manager which is used for the event queue */
86 /** Used to schedule sending of deferred packets. */
87 void processSendEvent();
89 /** Event used to call processSendEvent. */
90 EventWrapper<PacketQueue, &PacketQueue::processSendEvent> sendEvent;
94 /** Label to use for print request packets label stack. */
95 const std::string label;
97 /** Remember whether we're awaiting a retry. */
100 /** Check whether we have a packet ready to go on the transmit list. */
101 bool deferredPacketReady() const
102 { return !transmitList.empty() && transmitList.front().tick <= curTick(); }
105 * Attempt to send a packet. Note that a subclass of the
106 * PacketQueue can override this method and thus change the
107 * behaviour (as done by the cache for the request queue). The
108 * default implementation sends the head of the transmit list. The
109 * caller must guarantee that the list is non-empty and that the
110 * head packet is scheduled for curTick() (or earlier).
112 virtual void sendDeferredPacket();
115 * Send a packet using the appropriate method for the specific
116 * subclass (reuest, response or snoop response).
118 virtual bool sendTiming(PacketPtr pkt) = 0;
121 * Create a packet queue, linked to an event manager, and a label
122 * that will be used for functional print request packets.
124 * @param _em Event manager used for scheduling this queue
125 * @param _label Label to push on the label stack for print request packets
127 PacketQueue(EventManager& _em, const std::string& _label);
130 * Virtual desctructor since the class may be used as a base class.
132 virtual ~PacketQueue();
137 * Provide a name to simplify debugging.
139 * @return A complete name, appended to module and port
141 virtual const std::string name() const = 0;
144 * Get the size of the queue.
146 size_t size() const { return transmitList.size(); }
149 * Get the next packet ready time.
151 Tick deferredPacketReadyTime() const
152 { return transmitList.empty() ? MaxTick : transmitList.front().tick; }
155 * Check if a packets address exists in the queue.
157 bool hasAddr(Addr addr) const;
159 /** Check the list of buffered packets against the supplied
160 * functional request. */
161 bool checkFunctional(PacketPtr pkt);
164 * Schedule a send event if we are not already waiting for a
165 * retry. If the requested time is before an already scheduled
166 * send event, the event will be rescheduled. If MaxTick is
167 * passed, no event is scheduled. Instead, if we are idle and
168 * asked to drain then check and signal drained.
170 * @param when time to schedule an event
172 void schedSendEvent(Tick when);
175 * Add a packet to the transmit list, and schedule a send event.
177 * @param pkt Packet to send
178 * @param when Absolute time (in ticks) to send packet
179 * @param force_order Force insertion order for packets with same address
181 void schedSendTiming(PacketPtr pkt, Tick when, bool force_order = false);
184 * Retry sending a packet from the queue. Note that this is not
185 * necessarily the same packet if something has been added with an
186 * earlier time stamp.
190 DrainState drain() override;
193 class ReqPacketQueue : public PacketQueue
198 MasterPort& masterPort;
203 * Create a request packet queue, linked to an event manager, a
204 * master port, and a label that will be used for functional print
207 * @param _em Event manager used for scheduling this queue
208 * @param _masterPort Master port used to send the packets
209 * @param _label Label to push on the label stack for print request packets
211 ReqPacketQueue(EventManager& _em, MasterPort& _masterPort,
212 const std::string _label = "ReqPacketQueue");
214 virtual ~ReqPacketQueue() { }
216 const std::string name() const
217 { return masterPort.name() + "-" + label; }
219 bool sendTiming(PacketPtr pkt);
223 class SnoopRespPacketQueue : public PacketQueue
228 MasterPort& masterPort;
233 * Create a snoop response packet queue, linked to an event
234 * manager, a master port, and a label that will be used for
235 * functional print request packets.
237 * @param _em Event manager used for scheduling this queue
238 * @param _masterPort Master port used to send the packets
239 * @param _label Label to push on the label stack for print request packets
241 SnoopRespPacketQueue(EventManager& _em, MasterPort& _masterPort,
242 const std::string _label = "SnoopRespPacketQueue");
244 virtual ~SnoopRespPacketQueue() { }
246 const std::string name() const
247 { return masterPort.name() + "-" + label; }
249 bool sendTiming(PacketPtr pkt);
253 class RespPacketQueue : public PacketQueue
258 SlavePort& slavePort;
263 * Create a response packet queue, linked to an event manager, a
264 * slave port, and a label that will be used for functional print
267 * @param _em Event manager used for scheduling this queue
268 * @param _slavePort Slave port used to send the packets
269 * @param _label Label to push on the label stack for print request packets
271 RespPacketQueue(EventManager& _em, SlavePort& _slavePort,
272 const std::string _label = "RespPacketQueue");
274 virtual ~RespPacketQueue() { }
276 const std::string name() const
277 { return slavePort.name() + "-" + label; }
279 bool sendTiming(PacketPtr pkt);
283 #endif // __MEM_PACKET_QUEUE_HH__