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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 "base/hashmap.hh"
46 #include "base/range_map.hh"
47 #include "mem/mem_object.hh"
48 #include "mem/packet.hh"
49 #include "mem/port.hh"
50 #include "mem/request.hh"
51 #include "sim/eventq.hh"
53 class Bus : public MemObject
55 /** a globally unique id for this bus. */
57 /** the clock speed for the bus */
59 /** the width of the bus in bytes */
61 /** the next tick at which the bus will be idle */
66 static const int defaultId = -3; //Make it unique from Broadcast
72 range_map<Addr, int> portMap;
73 AddrRangeList defaultRange;
74 std::vector<DevMap> portSnoopList;
76 /** Function called by the port when the bus is recieving a Timing
78 bool recvTiming(PacketPtr pkt);
80 /** Function called by the port when the bus is recieving a Atomic
82 Tick recvAtomic(PacketPtr pkt);
84 /** Function called by the port when the bus is recieving a Functional
86 void recvFunctional(PacketPtr pkt);
88 /** Timing function called by port when it is once again able to process
90 void recvRetry(int id);
92 /** Function called by the port when the bus is recieving a status change.*/
93 void recvStatusChange(Port::Status status, int id);
95 /** Find which port connected to this bus (if any) should be given a packet
97 * @param addr Address to find port for.
98 * @param id Id of the port this packet was received from (to prevent
100 * @return pointer to port that the packet should be sent out of.
102 Port *findPort(Addr addr, int id);
104 /** Find all ports with a matching snoop range, except src port. Keep in mind
105 * that the ranges shouldn't overlap or you will get a double snoop to the same
106 * interface.and the cache will assert out.
107 * @param addr Address to find snoop prts for.
108 * @param id Id of the src port of the request to avoid calling snoop on src
109 * @return vector of IDs to snoop on
111 std::vector<int> findSnoopPorts(Addr addr, int id);
113 /** Snoop all relevant ports atomicly. */
114 Tick atomicSnoop(PacketPtr pkt, Port* responder);
116 /** Snoop all relevant ports functionally. */
117 void functionalSnoop(PacketPtr pkt, Port *responder);
119 /** Call snoop on caches, be sure to set SNOOP_COMMIT bit if you want
120 * the snoop to happen
121 * @return True if succeds.
123 bool timingSnoop(PacketPtr pkt, Port *responder);
125 /** Process address range request.
126 * @param resp addresses that we can respond to
127 * @param snoop addresses that we would like to snoop
128 * @param id ide of the busport that made the request.
130 void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
132 /** Occupy the bus with transmitting the packet pkt */
133 void occupyBus(PacketPtr pkt);
135 /** Declaration of the buses port type, one will be instantiated for each
136 of the interfaces connecting to the bus. */
137 class BusPort : public Port
141 /** A pointer to the bus to which this port belongs. */
144 /** A id to keep track of the intercafe ID this port is connected to. */
149 /** Constructor for the BusPort.*/
150 BusPort(const std::string &_name, Bus *_bus, int _id)
151 : Port(_name, _bus), _onRetryList(false), bus(_bus), id(_id)
155 { return _onRetryList; }
157 void onRetryList(bool newVal)
158 { _onRetryList = newVal; }
160 int getId() { return id; }
164 /** When reciving a timing request from the peer port (at id),
165 pass it to the bus. */
166 virtual bool recvTiming(PacketPtr pkt)
167 { pkt->setSrc(id); return bus->recvTiming(pkt); }
169 /** When reciving a Atomic requestfrom the peer port (at id),
170 pass it to the bus. */
171 virtual Tick recvAtomic(PacketPtr pkt)
172 { pkt->setSrc(id); return bus->recvAtomic(pkt); }
174 /** When reciving a Functional requestfrom the peer port (at id),
175 pass it to the bus. */
176 virtual void recvFunctional(PacketPtr pkt)
177 { pkt->setSrc(id); bus->recvFunctional(pkt); }
179 /** When reciving a status changefrom the peer port (at id),
180 pass it to the bus. */
181 virtual void recvStatusChange(Status status)
182 { bus->recvStatusChange(status, id); }
184 /** When reciving a retry from the peer port (at id),
185 pass it to the bus. */
186 virtual void recvRetry()
187 { bus->recvRetry(id); }
189 // This should return all the 'owned' addresses that are
190 // downstream from this bus, yes? That is, the union of all
191 // the 'owned' address ranges of all the other interfaces on
193 virtual void getDeviceAddressRanges(AddrRangeList &resp,
194 AddrRangeList &snoop)
195 { bus->addressRanges(resp, snoop, id); }
197 // Hack to make translating port work without changes
198 virtual int deviceBlockSize() { return 32; }
202 class BusFreeEvent : public Event
207 BusFreeEvent(Bus * _bus);
209 const char *description();
212 BusFreeEvent busIdle;
216 /** max number of bus ids we've handed out so far */
219 /** An array of pointers to the peer port interfaces
220 connected to this bus.*/
221 m5::hash_map<short,BusPort*> interfaces;
223 /** An array of pointers to ports that retry should be called on because the
224 * original send failed for whatever reason.*/
225 std::list<BusPort*> retryList;
227 void addToRetryList(BusPort * port)
230 // The device wasn't retrying a packet, or wasn't at an appropriate
232 assert(!port->onRetryList());
233 port->onRetryList(true);
234 retryList.push_back(port);
236 if (port->onRetryList()) {
237 // The device was retrying a packet. It didn't work, so we'll leave
238 // it at the head of the retry list.
239 assert(port == retryList.front());
243 port->onRetryList(true);
244 retryList.push_back(port);
249 /** Port that handles requests that don't match any of the interfaces.*/
250 BusPort *defaultPort;
252 /** Has the user specified their own default responder? */
257 /** A function used to return the port associated with this bus object. */
258 virtual Port *getPort(const std::string &if_name, int idx = -1);
259 virtual void deletePortRefs(Port *p);
263 unsigned int drain(Event *de);
265 Bus(const std::string &n, int bus_id, int _clock, int _width,
267 : MemObject(n), busId(bus_id), clock(_clock), width(_width),
268 tickNextIdle(0), drainEvent(NULL), busIdle(this), inRetry(false),
269 maxId(0), defaultPort(NULL), responderSet(responder_set)
271 //Both the width and clock period must be positive
273 fatal("Bus width must be positive\n");
275 fatal("Bus clock period must be positive\n");
280 #endif //__MEM_BUS_HH__