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/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"
  52
  53 class Bus : public MemObject
  54 {
  55     /** a globally unique id for this bus. */
  56     int busId;
  57     /** the clock speed for the bus */
  58     int clock;
  59     /** the width of the bus in bytes */
  60     int width;
  61     /** the next tick at which the bus will be idle */
  62     Tick tickNextIdle;
  63
  64     Event * drainEvent;
  65
  66     static const int defaultId = -3; //Make it unique from Broadcast
  67
  68     struct DevMap {
  69         int portId;
  70         Range<Addr> range;
  71     };
  72     range_map<Addr, int> portMap;
  73     AddrRangeList defaultRange;
  74     std::vector<DevMap> portSnoopList;
  75
  76     /** Function called by the port when the bus is recieving a Timing
  77       transaction.*/
  78     bool recvTiming(PacketPtr pkt);
  79
  80     /** Function called by the port when the bus is recieving a Atomic
  81       transaction.*/
  82     Tick recvAtomic(PacketPtr pkt);
  83
  84     /** Function called by the port when the bus is recieving a Functional
  85         transaction.*/
  86     void recvFunctional(PacketPtr pkt);
  87
  88     /** Timing function called by port when it is once again able to process
  89      * requests. */
  90     void recvRetry(int id);
  91
  92     /** Function called by the port when the bus is recieving a status change.*/
  93     void recvStatusChange(Port::Status status, int id);
  94
  95     /** Find which port connected to this bus (if any) should be given a packet
  96      * with this address.
  97      * @param addr Address to find port for.
  98      * @param id Id of the port this packet was received from (to prevent
  99      *             loops)
 100      * @return pointer to port that the packet should be sent out of.
 101      */
 102     Port *findPort(Addr addr, int id);
 103
 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
 110      */
 111     std::vector<int> findSnoopPorts(Addr addr, int id);
 112
 113     /** Snoop all relevant ports atomicly. */
 114     Tick atomicSnoop(PacketPtr pkt, Port* responder);
 115
 116     /** Snoop all relevant ports functionally. */
 117     void functionalSnoop(PacketPtr pkt, Port *responder);
 118
 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.
 122      */
 123     bool timingSnoop(PacketPtr pkt, Port *responder);
 124
 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.
 129      */
 130     void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
 131
 132     /** Occupy the bus with transmitting the packet pkt */
 133     void occupyBus(PacketPtr pkt);
 134
 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
 138     {
 139         bool _onRetryList;
 140
 141         /** A pointer to the bus to which this port belongs. */
 142         Bus *bus;
 143
 144         /** A id to keep track of the intercafe ID this port is connected to. */
 145         int id;
 146
 147       public:
 148
 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)
 152         { }
 153
 154         bool onRetryList()
 155         { return _onRetryList; }
 156
 157         void onRetryList(bool newVal)
 158         { _onRetryList = newVal; }
 159
 160         int getId() { return id; }
 161
 162       protected:
 163
 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); }
 168
 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); }
 173
 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); }
 178
 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); }
 183
 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); }
 188
 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
 192         // this bus...
 193         virtual void getDeviceAddressRanges(AddrRangeList &resp,
 194                                             AddrRangeList &snoop)
 195         { bus->addressRanges(resp, snoop, id); }
 196
 197         // Hack to make translating port work without changes
 198         virtual int deviceBlockSize() { return 32; }
 199
 200     };
 201
 202     class BusFreeEvent : public Event
 203     {
 204         Bus * bus;
 205
 206       public:
 207         BusFreeEvent(Bus * _bus);
 208         void process();
 209         const char *description();
 210     };
 211
 212     BusFreeEvent busIdle;
 213
 214     bool inRetry;
 215
 216     /** max number of bus ids we've handed out so far */
 217     short maxId;
 218
 219     /** An array of pointers to the peer port interfaces
 220         connected to this bus.*/
 221     m5::hash_map<short,BusPort*> interfaces;
 222
 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;
 226
 227     void addToRetryList(BusPort * port)
 228     {
 229         if (!inRetry) {
 230             // The device wasn't retrying a packet, or wasn't at an appropriate
 231             // time.
 232             assert(!port->onRetryList());
 233             port->onRetryList(true);
 234             retryList.push_back(port);
 235         } else {
 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());
 240                 inRetry = false;
 241             }
 242             else {
 243                 port->onRetryList(true);
 244                 retryList.push_back(port);
 245             }
 246         }
 247     }
 248
 249     /** Port that handles requests that don't match any of the interfaces.*/
 250     BusPort *defaultPort;
 251
 252     /** Has the user specified their own default responder? */
 253     bool responderSet;
 254
 255   public:
 256
 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);
 260
 261     virtual void init();
 262
 263     unsigned int drain(Event *de);
 264
 265     Bus(const std::string &n, int bus_id, int _clock, int _width,
 266         bool responder_set)
 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)
 270     {
 271         //Both the width and clock period must be positive
 272         if (width <= 0)
 273             fatal("Bus width must be positive\n");
 274         if (clock <= 0)
 275             fatal("Bus clock period must be positive\n");
 276     }
 277
 278 };
 279
 280 #endif //__MEM_BUS_HH__