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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 = -3; //Make it unique from Broadcast
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(PacketPtr pkt);
76 /** Function called by the port when the bus is recieving a Atomic
78 Tick recvAtomic(PacketPtr pkt);
80 /** Function called by the port when the bus is recieving a Functional
82 void recvFunctional(PacketPtr 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 Tick atomicSnoop(PacketPtr pkt);
112 /** Snoop all relevant ports functionally. */
113 void functionalSnoop(PacketPtr 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(PacketPtr 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);
128 /** Occupy the bus with transmitting the packet pkt */
129 void occupyBus(PacketPtr pkt);
131 /** Declaration of the buses port type, one will be instantiated for each
132 of the interfaces connecting to the bus. */
133 class BusPort : public Port
137 /** A pointer to the bus to which this port belongs. */
140 /** A id to keep track of the intercafe ID this port is connected to. */
145 /** Constructor for the BusPort.*/
146 BusPort(const std::string &_name, Bus *_bus, int _id)
147 : Port(_name), _onRetryList(false), bus(_bus), id(_id)
151 { return _onRetryList; }
153 void onRetryList(bool newVal)
154 { _onRetryList = newVal; }
158 /** When reciving a timing request from the peer port (at id),
159 pass it to the bus. */
160 virtual bool recvTiming(PacketPtr pkt)
161 { pkt->setSrc(id); return bus->recvTiming(pkt); }
163 /** When reciving a Atomic requestfrom the peer port (at id),
164 pass it to the bus. */
165 virtual Tick recvAtomic(PacketPtr pkt)
166 { pkt->setSrc(id); return bus->recvAtomic(pkt); }
168 /** When reciving a Functional requestfrom the peer port (at id),
169 pass it to the bus. */
170 virtual void recvFunctional(PacketPtr pkt)
171 { pkt->setSrc(id); bus->recvFunctional(pkt); }
173 /** When reciving a status changefrom the peer port (at id),
174 pass it to the bus. */
175 virtual void recvStatusChange(Status status)
176 { bus->recvStatusChange(status, id); }
178 /** When reciving a retry from the peer port (at id),
179 pass it to the bus. */
180 virtual void recvRetry()
181 { bus->recvRetry(id); }
183 // This should return all the 'owned' addresses that are
184 // downstream from this bus, yes? That is, the union of all
185 // the 'owned' address ranges of all the other interfaces on
187 virtual void getDeviceAddressRanges(AddrRangeList &resp,
188 AddrRangeList &snoop)
189 { bus->addressRanges(resp, snoop, id); }
191 // Hack to make translating port work without changes
192 virtual int deviceBlockSize() { return 32; }
196 class BusFreeEvent : public Event
201 BusFreeEvent(Bus * _bus);
203 const char *description();
206 BusFreeEvent busIdle;
210 /** An array of pointers to the peer port interfaces
211 connected to this bus.*/
212 std::vector<BusPort*> interfaces;
214 /** An array of pointers to ports that retry should be called on because the
215 * original send failed for whatever reason.*/
216 std::list<BusPort*> retryList;
218 void addToRetryList(BusPort * port)
221 // The device wasn't retrying a packet, or wasn't at an appropriate
223 assert(!port->onRetryList());
224 port->onRetryList(true);
225 retryList.push_back(port);
227 if (port->onRetryList()) {
228 // The device was retrying a packet. It didn't work, so we'll leave
229 // it at the head of the retry list.
230 assert(port == retryList.front());
234 port->onRetryList(true);
235 retryList.push_back(port);
240 /** Port that handles requests that don't match any of the interfaces.*/
241 BusPort *defaultPort;
245 /** A function used to return the port associated with this bus object. */
246 virtual Port *getPort(const std::string &if_name, int idx = -1);
250 Bus(const std::string &n, int bus_id, int _clock, int _width)
251 : MemObject(n), busId(bus_id), clock(_clock), width(_width),
252 tickNextIdle(0), busIdle(this), inRetry(false), defaultPort(NULL)
254 //Both the width and clock period must be positive
256 fatal("Bus width must be positive\n");
258 fatal("Bus clock period must be positive\n");
263 #endif //__MEM_BUS_HH__