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28 * Authors: Ron Dreslinski
34 * Declaration of a bus object.
37 #ifndef __MEM_BUS_HH__
38 #define __MEM_BUS_HH__
44 #include "base/range.hh"
45 #include "mem/mem_object.hh"
46 #include "mem/packet.hh"
47 #include "mem/port.hh"
48 #include "mem/request.hh"
49 #include "sim/eventq.hh"
51 class Bus : public MemObject
53 /** a globally unique id for this bus. */
55 /** the clock speed for the bus */
57 /** the width of the bus in bytes */
59 /** the next tick at which the bus will be idle */
62 static const int defaultId = -1;
68 std::vector<DevMap> portList;
69 AddrRangeList defaultRange;
70 std::vector<DevMap> portSnoopList;
72 /** Function called by the port when the bus is recieving a Timing
74 bool recvTiming(Packet *pkt);
76 /** Function called by the port when the bus is recieving a Atomic
78 Tick recvAtomic(Packet *pkt);
80 /** Function called by the port when the bus is recieving a Functional
82 void recvFunctional(Packet *pkt);
84 /** Timing function called by port when it is once again able to process
86 void recvRetry(int id);
88 /** Function called by the port when the bus is recieving a status change.*/
89 void recvStatusChange(Port::Status status, int id);
91 /** Find which port connected to this bus (if any) should be given a packet
93 * @param addr Address to find port for.
94 * @param id Id of the port this packet was received from (to prevent
96 * @return pointer to port that the packet should be sent out of.
98 Port *findPort(Addr addr, int id);
100 /** Find all ports with a matching snoop range, except src port. Keep in mind
101 * that the ranges shouldn't overlap or you will get a double snoop to the same
102 * interface.and the cache will assert out.
103 * @param addr Address to find snoop prts for.
104 * @param id Id of the src port of the request to avoid calling snoop on src
105 * @return vector of IDs to snoop on
107 std::vector<int> findSnoopPorts(Addr addr, int id);
109 /** Snoop all relevant ports atomicly. */
110 void atomicSnoop(Packet *pkt);
112 /** Snoop all relevant ports functionally. */
113 void functionalSnoop(Packet *pkt);
115 /** Call snoop on caches, be sure to set SNOOP_COMMIT bit if you want
116 * the snoop to happen
117 * @return True if succeds.
119 bool timingSnoop(Packet *pkt);
121 /** Process address range request.
122 * @param resp addresses that we can respond to
123 * @param snoop addresses that we would like to snoop
124 * @param id ide of the busport that made the request.
126 void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
129 /** Declaration of the buses port type, one will be instantiated for each
130 of the interfaces connecting to the bus. */
131 class BusPort : public Port
133 /** A pointer to the bus to which this port belongs. */
136 /** A id to keep track of the intercafe ID this port is connected to. */
141 /** Constructor for the BusPort.*/
142 BusPort(const std::string &_name, Bus *_bus, int _id)
143 : Port(_name), bus(_bus), id(_id)
148 /** When reciving a timing request from the peer port (at id),
149 pass it to the bus. */
150 virtual bool recvTiming(Packet *pkt)
151 { pkt->setSrc(id); return bus->recvTiming(pkt); }
153 /** When reciving a Atomic requestfrom the peer port (at id),
154 pass it to the bus. */
155 virtual Tick recvAtomic(Packet *pkt)
156 { pkt->setSrc(id); return bus->recvAtomic(pkt); }
158 /** When reciving a Functional requestfrom the peer port (at id),
159 pass it to the bus. */
160 virtual void recvFunctional(Packet *pkt)
161 { pkt->setSrc(id); bus->recvFunctional(pkt); }
163 /** When reciving a status changefrom the peer port (at id),
164 pass it to the bus. */
165 virtual void recvStatusChange(Status status)
166 { bus->recvStatusChange(status, id); }
168 /** When reciving a retry from the peer port (at id),
169 pass it to the bus. */
170 virtual void recvRetry()
171 { bus->recvRetry(id); }
173 // This should return all the 'owned' addresses that are
174 // downstream from this bus, yes? That is, the union of all
175 // the 'owned' address ranges of all the other interfaces on
177 virtual void getDeviceAddressRanges(AddrRangeList &resp,
178 AddrRangeList &snoop)
179 { bus->addressRanges(resp, snoop, id); }
181 // Hack to make translating port work without changes
182 virtual int deviceBlockSize() { return 32; }
186 class BusFreeEvent : public Event
191 BusFreeEvent(Bus * _bus);
193 const char *description();
196 BusFreeEvent busIdle;
198 void occupyBus(int numCycles);
202 /** An array of pointers to the peer port interfaces
203 connected to this bus.*/
204 std::vector<Port*> interfaces;
206 /** An array of pointers to ports that retry should be called on because the
207 * original send failed for whatever reason.*/
208 std::list<Port*> retryList;
210 void addToRetryList(Port * port)
213 // The device wasn't retrying a packet, or wasn't at an appropriate
215 retryList.push_back(port);
217 // The device was retrying a packet. It didn't work, so we'll leave
218 // it at the head of the retry list.
221 // We shouldn't be receiving a packet from one port when a different
223 assert(port == retryingPort);
227 /** Port that handles requests that don't match any of the interfaces.*/
232 /** A function used to return the port associated with this bus object. */
233 virtual Port *getPort(const std::string &if_name, int idx = -1);
237 Bus(const std::string &n, int bus_id, int _clock, int _width)
238 : MemObject(n), busId(bus_id), clock(_clock), width(_width),
239 tickNextIdle(0), busIdle(this), retryingPort(NULL), defaultPort(NULL)
241 //Both the width and clock period must be positive
248 #endif //__MEM_BUS_HH__