src/mem/bus.hh

   1 /*
   2  * Copyright (c) 2002-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Ron Dreslinski
  29  *          Ali Saidi
  30  */
  31
  32 /**
  33  * @file
  34  * Declaration of a bus object.
  35  */
  36
  37 #ifndef __MEM_BUS_HH__
  38 #define __MEM_BUS_HH__
  39
  40 #include <string>
  41 #include <list>
  42 #include <inttypes.h>
  43
  44 #include "base/range.hh"
  45 #include "base/range_map.hh"
  46 #include "mem/mem_object.hh"
  47 #include "mem/packet.hh"
  48 #include "mem/port.hh"
  49 #include "mem/request.hh"
  50 #include "sim/eventq.hh"
  51
  52 class Bus : public MemObject
  53 {
  54     /** a globally unique id for this bus. */
  55     int busId;
  56     /** the clock speed for the bus */
  57     int clock;
  58     /** the width of the bus in bytes */
  59     int width;
  60     /** the next tick at which the bus will be idle */
  61     Tick tickNextIdle;
  62
  63     Event * drainEvent;
  64
  65     static const int defaultId = -3; //Make it unique from Broadcast
  66
  67     struct DevMap {
  68         int portId;
  69         Range<Addr> range;
  70     };
  71     range_map<Addr, int> portMap;
  72     AddrRangeList defaultRange;
  73     std::vector<DevMap> portSnoopList;
  74
  75     /** Function called by the port when the bus is recieving a Timing
  76       transaction.*/
  77     bool recvTiming(PacketPtr pkt);
  78
  79     /** Function called by the port when the bus is recieving a Atomic
  80       transaction.*/
  81     Tick recvAtomic(PacketPtr pkt);
  82
  83     /** Function called by the port when the bus is recieving a Functional
  84         transaction.*/
  85     void recvFunctional(PacketPtr pkt);
  86
  87     /** Timing function called by port when it is once again able to process
  88      * requests. */
  89     void recvRetry(int id);
  90
  91     /** Function called by the port when the bus is recieving a status change.*/
  92     void recvStatusChange(Port::Status status, int id);
  93
  94     /** Find which port connected to this bus (if any) should be given a packet
  95      * with this address.
  96      * @param addr Address to find port for.
  97      * @param id Id of the port this packet was received from (to prevent
  98      *             loops)
  99      * @return pointer to port that the packet should be sent out of.
 100      */
 101     Port *findPort(Addr addr, int id);
 102
 103     /** Find all ports with a matching snoop range, except src port.  Keep in mind
 104      * that the ranges shouldn't overlap or you will get a double snoop to the same
 105      * interface.and the cache will assert out.
 106      * @param addr Address to find snoop prts for.
 107      * @param id Id of the src port of the request to avoid calling snoop on src
 108      * @return vector of IDs to snoop on
 109      */
 110     std::vector<int> findSnoopPorts(Addr addr, int id);
 111
 112     /** Snoop all relevant ports atomicly. */
 113     Tick atomicSnoop(PacketPtr pkt, Port* responder);
 114
 115     /** Snoop all relevant ports functionally. */
 116     void functionalSnoop(PacketPtr pkt, Port *responder);
 117
 118     /** Call snoop on caches, be sure to set SNOOP_COMMIT bit if you want
 119      * the snoop to happen
 120      * @return True if succeds.
 121      */
 122     bool timingSnoop(PacketPtr pkt, Port *responder);
 123
 124     /** Process address range request.
 125      * @param resp addresses that we can respond to
 126      * @param snoop addresses that we would like to snoop
 127      * @param id ide of the busport that made the request.
 128      */
 129     void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
 130
 131     /** Occupy the bus with transmitting the packet pkt */
 132     void occupyBus(PacketPtr pkt);
 133
 134     /** Declaration of the buses port type, one will be instantiated for each
 135         of the interfaces connecting to the bus. */
 136     class BusPort : public Port
 137     {
 138         bool _onRetryList;
 139
 140         /** A pointer to the bus to which this port belongs. */
 141         Bus *bus;
 142
 143         /** A id to keep track of the intercafe ID this port is connected to. */
 144         int id;
 145
 146       public:
 147
 148         /** Constructor for the BusPort.*/
 149         BusPort(const std::string &_name, Bus *_bus, int _id)
 150             : Port(_name, _bus), _onRetryList(false), bus(_bus), id(_id)
 151         { }
 152
 153         bool onRetryList()
 154         { return _onRetryList; }
 155
 156         void onRetryList(bool newVal)
 157         { _onRetryList = newVal; }
 158
 159         int getId() { return id; }
 160
 161       protected:
 162
 163         /** When reciving a timing request from the peer port (at id),
 164             pass it to the bus. */
 165         virtual bool recvTiming(PacketPtr pkt)
 166         { pkt->setSrc(id); return bus->recvTiming(pkt); }
 167
 168         /** When reciving a Atomic requestfrom the peer port (at id),
 169             pass it to the bus. */
 170         virtual Tick recvAtomic(PacketPtr pkt)
 171         { pkt->setSrc(id); return bus->recvAtomic(pkt); }
 172
 173         /** When reciving a Functional requestfrom the peer port (at id),
 174             pass it to the bus. */
 175         virtual void recvFunctional(PacketPtr pkt)
 176         { pkt->setSrc(id); bus->recvFunctional(pkt); }
 177
 178         /** When reciving a status changefrom the peer port (at id),
 179             pass it to the bus. */
 180         virtual void recvStatusChange(Status status)
 181         { bus->recvStatusChange(status, id); }
 182
 183         /** When reciving a retry from the peer port (at id),
 184             pass it to the bus. */
 185         virtual void recvRetry()
 186         { bus->recvRetry(id); }
 187
 188         // This should return all the 'owned' addresses that are
 189         // downstream from this bus, yes?  That is, the union of all
 190         // the 'owned' address ranges of all the other interfaces on
 191         // this bus...
 192         virtual void getDeviceAddressRanges(AddrRangeList &resp,
 193                                             AddrRangeList &snoop)
 194         { bus->addressRanges(resp, snoop, id); }
 195
 196         // Hack to make translating port work without changes
 197         virtual int deviceBlockSize() { return 32; }
 198
 199     };
 200
 201     class BusFreeEvent : public Event
 202     {
 203         Bus * bus;
 204
 205       public:
 206         BusFreeEvent(Bus * _bus);
 207         void process();
 208         const char *description();
 209     };
 210
 211     BusFreeEvent busIdle;
 212
 213     bool inRetry;
 214
 215     /** An array of pointers to the peer port interfaces
 216         connected to this bus.*/
 217     std::vector<BusPort*> interfaces;
 218
 219     /** An array of pointers to ports that retry should be called on because the
 220      * original send failed for whatever reason.*/
 221     std::list<BusPort*> retryList;
 222
 223     void addToRetryList(BusPort * port)
 224     {
 225         if (!inRetry) {
 226             // The device wasn't retrying a packet, or wasn't at an appropriate
 227             // time.
 228             assert(!port->onRetryList());
 229             port->onRetryList(true);
 230             retryList.push_back(port);
 231         } else {
 232             if (port->onRetryList()) {
 233                 // The device was retrying a packet. It didn't work, so we'll leave
 234                 // it at the head of the retry list.
 235                 assert(port == retryList.front());
 236                 inRetry = false;
 237             }
 238             else {
 239                 port->onRetryList(true);
 240                 retryList.push_back(port);
 241             }
 242         }
 243     }
 244
 245     /** Port that handles requests that don't match any of the interfaces.*/
 246     BusPort *defaultPort;
 247
 248     /** Has the user specified their own default responder? */
 249     bool responderSet;
 250
 251   public:
 252
 253     /** A function used to return the port associated with this bus object. */
 254     virtual Port *getPort(const std::string &if_name, int idx = -1);
 255
 256     virtual void init();
 257
 258     unsigned int drain(Event *de);
 259
 260     Bus(const std::string &n, int bus_id, int _clock, int _width,
 261         bool responder_set)
 262         : MemObject(n), busId(bus_id), clock(_clock), width(_width),
 263           tickNextIdle(0), drainEvent(NULL), busIdle(this), inRetry(false),
 264           defaultPort(NULL), responderSet(responder_set)
 265     {
 266         //Both the width and clock period must be positive
 267         if (width <= 0)
 268             fatal("Bus width must be positive\n");
 269         if (clock <= 0)
 270             fatal("Bus clock period must be positive\n");
 271     }
 272
 273 };
 274
 275 #endif //__MEM_BUS_HH__