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41 #ifndef __MEM_PACKET_QUEUE_HH__
42 #define __MEM_PACKET_QUEUE_HH__
46 * Declaration of a simple PacketQueue that is associated with
47 * a port on which it attempts to send packets according to the time
48 * stamp given to them at insertion. The packet queue is responsible
49 * for the flow control of the port.
54 #include "mem/port.hh"
55 #include "sim/drain.hh"
56 #include "sim/eventq_impl.hh"
59 * A packet queue is a class that holds deferred packets and later
60 * sends them using the associated slave port or master port.
62 class PacketQueue : public Drainable
65 /** A deferred packet, buffered to transmit later. */
66 class DeferredPacket {
68 Tick tick; ///< The tick when the packet is ready to transmit
69 PacketPtr pkt; ///< Pointer to the packet to transmit
70 DeferredPacket(Tick t, PacketPtr p)
75 typedef std::list<DeferredPacket> DeferredPacketList;
77 /** A list of outgoing packets. */
78 DeferredPacketList transmitList;
80 /** The manager which is used for the event queue */
83 /** Used to schedule sending of deferred packets. */
84 void processSendEvent();
86 /** Event used to call processSendEvent. */
87 EventFunctionWrapper sendEvent;
90 * Optionally disable the sanity check
91 * on the size of the transmitList. The
92 * sanity check will be enabled by default.
94 bool _disableSanityCheck;
97 * if true, inserted packets have to be unconditionally scheduled
98 * after the last packet in the queue that references the same
105 /** Label to use for print request packets label stack. */
106 const std::string label;
108 /** Remember whether we're awaiting a retry. */
111 /** Check whether we have a packet ready to go on the transmit list. */
112 bool deferredPacketReady() const
113 { return !transmitList.empty() && transmitList.front().tick <= curTick(); }
116 * Attempt to send a packet. Note that a subclass of the
117 * PacketQueue can override this method and thus change the
118 * behaviour (as done by the cache for the request queue). The
119 * default implementation sends the head of the transmit list. The
120 * caller must guarantee that the list is non-empty and that the
121 * head packet is scheduled for curTick() (or earlier).
123 virtual void sendDeferredPacket();
126 * Send a packet using the appropriate method for the specific
127 * subclass (reuest, response or snoop response).
129 virtual bool sendTiming(PacketPtr pkt) = 0;
132 * Create a packet queue, linked to an event manager, and a label
133 * that will be used for functional print request packets.
135 * @param _em Event manager used for scheduling this queue
136 * @param _label Label to push on the label stack for print request packets
137 * @param force_order Force insertion order for packets with same address
138 * @param disable_sanity_check Flag used to disable the sanity check
139 * on the size of the transmitList. The check is enabled by default.
141 PacketQueue(EventManager& _em, const std::string& _label,
142 const std::string& _sendEventName,
143 bool force_order = false,
144 bool disable_sanity_check = false);
147 * Virtual desctructor since the class may be used as a base class.
149 virtual ~PacketQueue();
154 * Provide a name to simplify debugging.
156 * @return A complete name, appended to module and port
158 virtual const std::string name() const = 0;
161 * Get the size of the queue.
163 size_t size() const { return transmitList.size(); }
166 * Get the next packet ready time.
168 Tick deferredPacketReadyTime() const
169 { return transmitList.empty() ? MaxTick : transmitList.front().tick; }
172 * Check if a packet corresponding to the same address exists in the
175 * @param pkt The packet to compare against.
176 * @param blk_size Block size in bytes.
177 * @return Whether a corresponding packet is found.
179 bool checkConflict(const PacketPtr pkt, const int blk_size) const;
181 /** Check the list of buffered packets against the supplied
182 * functional request. */
183 bool trySatisfyFunctional(PacketPtr pkt);
186 * Schedule a send event if we are not already waiting for a
187 * retry. If the requested time is before an already scheduled
188 * send event, the event will be rescheduled. If MaxTick is
189 * passed, no event is scheduled. Instead, if we are idle and
190 * asked to drain then check and signal drained.
192 * @param when time to schedule an event
194 void schedSendEvent(Tick when);
197 * Add a packet to the transmit list, and schedule a send event.
199 * @param pkt Packet to send
200 * @param when Absolute time (in ticks) to send packet
202 void schedSendTiming(PacketPtr pkt, Tick when);
205 * Retry sending a packet from the queue. Note that this is not
206 * necessarily the same packet if something has been added with an
207 * earlier time stamp.
212 * This allows a user to explicitly disable the sanity check
213 * on the size of the transmitList, which is enabled by default.
214 * Users must use this function to explicitly disable the sanity
217 void disableSanityCheck() { _disableSanityCheck = true; }
219 DrainState drain() override;
222 class ReqPacketQueue : public PacketQueue
227 MasterPort& masterPort;
229 // Static definition so it can be called when constructing the parent
230 // without us being completely initialized.
231 static const std::string name(const MasterPort& masterPort,
232 const std::string& label)
233 { return masterPort.name() + "-" + label; }
238 * Create a request packet queue, linked to an event manager, a
239 * master port, and a label that will be used for functional print
242 * @param _em Event manager used for scheduling this queue
243 * @param _masterPort Master port used to send the packets
244 * @param _label Label to push on the label stack for print request packets
246 ReqPacketQueue(EventManager& _em, MasterPort& _masterPort,
247 const std::string _label = "ReqPacketQueue");
249 virtual ~ReqPacketQueue() { }
251 const std::string name() const
252 { return name(masterPort, label); }
254 bool sendTiming(PacketPtr pkt);
258 class SnoopRespPacketQueue : public PacketQueue
263 MasterPort& masterPort;
265 // Static definition so it can be called when constructing the parent
266 // without us being completely initialized.
267 static const std::string name(const MasterPort& masterPort,
268 const std::string& label)
269 { return masterPort.name() + "-" + label; }
274 * Create a snoop response packet queue, linked to an event
275 * manager, a master port, and a label that will be used for
276 * functional print request packets.
278 * @param _em Event manager used for scheduling this queue
279 * @param _masterPort Master port used to send the packets
280 * @param force_order Force insertion order for packets with same address
281 * @param _label Label to push on the label stack for print request packets
283 SnoopRespPacketQueue(EventManager& _em, MasterPort& _masterPort,
284 bool force_order = false,
285 const std::string _label = "SnoopRespPacketQueue");
287 virtual ~SnoopRespPacketQueue() { }
289 const std::string name() const
290 { return name(masterPort, label); }
292 bool sendTiming(PacketPtr pkt);
296 class RespPacketQueue : public PacketQueue
301 SlavePort& slavePort;
303 // Static definition so it can be called when constructing the parent
304 // without us being completely initialized.
305 static const std::string name(const SlavePort& slavePort,
306 const std::string& label)
307 { return slavePort.name() + "-" + label; }
312 * Create a response packet queue, linked to an event manager, a
313 * slave port, and a label that will be used for functional print
316 * @param _em Event manager used for scheduling this queue
317 * @param _slavePort Slave port used to send the packets
318 * @param force_order Force insertion order for packets with same address
319 * @param _label Label to push on the label stack for print request packets
321 RespPacketQueue(EventManager& _em, SlavePort& _slavePort,
322 bool force_order = false,
323 const std::string _label = "RespPacketQueue");
325 virtual ~RespPacketQueue() { }
327 const std::string name() const
328 { return name(slavePort, label); }
330 bool sendTiming(PacketPtr pkt);
334 #endif // __MEM_PACKET_QUEUE_HH__