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40 * Authors: Ron Dreslinski
48 * Declaration of a coherent bus.
51 #ifndef __MEM_COHERENT_BUS_HH__
52 #define __MEM_COHERENT_BUS_HH__
55 #include "params/CoherentBus.hh"
58 * A coherent bus connects a number of (potentially) snooping masters
59 * and slaves, and routes the request and response packets based on
60 * the address, and also forwards all requests to the snoopers and
61 * deals with the snoop responses.
63 * The coherent bus can be used as a template for modelling QPI,
64 * HyperTransport, ACE and coherent OCP buses, and is typically used
65 * for the L1-to-L2 buses and as the main system interconnect.
67 class CoherentBus : public BaseBus
73 * Declaration of the coherent bus slave port type, one will be
74 * instantiated for each of the master ports connecting to the
77 class CoherentBusSlavePort : public SlavePort
82 /** A reference to the bus to which this port belongs. */
87 CoherentBusSlavePort(const std::string &_name,
88 CoherentBus &_bus, PortID _id)
89 : SlavePort(_name, &_bus, _id), bus(_bus)
95 * When receiving a timing request, pass it to the bus.
97 virtual bool recvTimingReq(PacketPtr pkt)
98 { return bus.recvTimingReq(pkt, id); }
101 * When receiving a timing snoop response, pass it to the bus.
103 virtual bool recvTimingSnoopResp(PacketPtr pkt)
104 { return bus.recvTimingSnoopResp(pkt, id); }
107 * When receiving an atomic request, pass it to the bus.
109 virtual Tick recvAtomic(PacketPtr pkt)
110 { return bus.recvAtomic(pkt, id); }
113 * When receiving a functional request, pass it to the bus.
115 virtual void recvFunctional(PacketPtr pkt)
116 { bus.recvFunctional(pkt, id); }
119 * When receiving a retry, pass it to the bus.
121 virtual void recvRetry()
122 { panic("Bus slave ports always succeed and should never retry.\n"); }
125 * Return the union of all adress ranges seen by this bus.
127 virtual AddrRangeList getAddrRanges()
128 { return bus.getAddrRanges(); }
131 * Get the maximum block size as seen by the bus.
133 virtual unsigned deviceBlockSize() const
134 { return bus.findBlockSize(); }
139 * Declaration of the coherent bus master port type, one will be
140 * instantiated for each of the slave interfaces connecting to the
143 class CoherentBusMasterPort : public MasterPort
146 /** A reference to the bus to which this port belongs. */
151 CoherentBusMasterPort(const std::string &_name,
152 CoherentBus &_bus, PortID _id)
153 : MasterPort(_name, &_bus, _id), bus(_bus)
159 * Determine if this port should be considered a snooper. For
160 * a coherent bus master port this is always true.
162 * @return a boolean that is true if this port is snooping
164 virtual bool isSnooping() const
168 * When receiving a timing response, pass it to the bus.
170 virtual bool recvTimingResp(PacketPtr pkt)
171 { return bus.recvTimingResp(pkt, id); }
174 * When receiving a timing snoop request, pass it to the bus.
176 virtual void recvTimingSnoopReq(PacketPtr pkt)
177 { return bus.recvTimingSnoopReq(pkt, id); }
180 * When receiving an atomic snoop request, pass it to the bus.
182 virtual Tick recvAtomicSnoop(PacketPtr pkt)
183 { return bus.recvAtomicSnoop(pkt, id); }
186 * When receiving a functional snoop request, pass it to the bus.
188 virtual void recvFunctionalSnoop(PacketPtr pkt)
189 { bus.recvFunctionalSnoop(pkt, id); }
191 /** When reciving a range change from the peer port (at id),
192 pass it to the bus. */
193 virtual void recvRangeChange()
194 { bus.recvRangeChange(id); }
196 /** When reciving a retry from the peer port (at id),
197 pass it to the bus. */
198 virtual void recvRetry()
201 // Ask the bus to ask everyone on the bus what their block size is and
202 // take the max of it. This might need to be changed a bit if we ever
203 // support multiple block sizes.
204 virtual unsigned deviceBlockSize() const
205 { return bus.findBlockSize(); }
209 std::vector<SlavePort*> snoopPorts;
212 * Store the outstanding requests so we can determine which ones
213 * we generated and which ones were merely forwarded. This is used
214 * in the coherent bus when coherency responses come back.
216 std::set<RequestPtr> outstandingReq;
218 /** Function called by the port when the bus is recieving a Timing
220 bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
222 /** Function called by the port when the bus is recieving a Timing
224 bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
226 /** Function called by the port when the bus is recieving a timing
228 void recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id);
230 /** Function called by the port when the bus is recieving a timing
232 bool recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id);
235 * Forward a timing packet to our snoopers, potentially excluding
236 * one of the connected coherent masters to avoid sending a packet
237 * back to where it came from.
239 * @param pkt Packet to forward
240 * @param exclude_slave_port_id Id of slave port to exclude
242 void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id);
244 /** Function called by the port when the bus is recieving a Atomic
246 Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
248 /** Function called by the port when the bus is recieving an
249 atomic snoop transaction.*/
250 Tick recvAtomicSnoop(PacketPtr pkt, PortID master_port_id);
253 * Forward an atomic packet to our snoopers, potentially excluding
254 * one of the connected coherent masters to avoid sending a packet
255 * back to where it came from.
257 * @param pkt Packet to forward
258 * @param exclude_slave_port_id Id of slave port to exclude
260 * @return a pair containing the snoop response and snoop latency
262 std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
263 PortID exclude_slave_port_id);
265 /** Function called by the port when the bus is recieving a Functional
267 void recvFunctional(PacketPtr pkt, PortID slave_port_id);
269 /** Function called by the port when the bus is recieving a functional
271 void recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id);
274 * Forward a functional packet to our snoopers, potentially
275 * excluding one of the connected coherent masters to avoid
276 * sending a packet back to where it came from.
278 * @param pkt Packet to forward
279 * @param exclude_slave_port_id Id of slave port to exclude
281 void forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id);
287 CoherentBus(const CoherentBusParams *p);
290 #endif //__MEM_COHERENT_BUS_HH__