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     /** Declaration of the buses port type, one will be instantiated for each
  56         of the interfaces connecting to the bus. */
  57     class BusPort : public Port
  58     {
  59         bool _onRetryList;
  60
  61         /** A pointer to the bus to which this port belongs. */
  62         Bus *bus;
  63
  64         /** A id to keep track of the intercafe ID this port is connected to. */
  65         int id;
  66
  67       public:
  68
  69         /** Constructor for the BusPort.*/
  70         BusPort(const std::string &_name, Bus *_bus, int _id)
  71             : Port(_name, _bus), _onRetryList(false), bus(_bus), id(_id)
  72         { }
  73
  74         bool onRetryList()
  75         { return _onRetryList; }
  76
  77         void onRetryList(bool newVal)
  78         { _onRetryList = newVal; }
  79
  80         int getId() { return id; }
  81
  82       protected:
  83
  84         /** When reciving a timing request from the peer port (at id),
  85             pass it to the bus. */
  86         virtual bool recvTiming(PacketPtr pkt)
  87         { pkt->setSrc(id); return bus->recvTiming(pkt); }
  88
  89         /** When reciving a Atomic requestfrom the peer port (at id),
  90             pass it to the bus. */
  91         virtual Tick recvAtomic(PacketPtr pkt)
  92         { pkt->setSrc(id); return bus->recvAtomic(pkt); }
  93
  94         /** When reciving a Functional requestfrom the peer port (at id),
  95             pass it to the bus. */
  96         virtual void recvFunctional(PacketPtr pkt)
  97         { pkt->setSrc(id); bus->recvFunctional(pkt); }
  98
  99         /** When reciving a status changefrom the peer port (at id),
 100             pass it to the bus. */
 101         virtual void recvStatusChange(Status status)
 102         { bus->recvStatusChange(status, id); }
 103
 104         /** When reciving a retry from the peer port (at id),
 105             pass it to the bus. */
 106         virtual void recvRetry()
 107         { bus->recvRetry(id); }
 108
 109         // This should return all the 'owned' addresses that are
 110         // downstream from this bus, yes?  That is, the union of all
 111         // the 'owned' address ranges of all the other interfaces on
 112         // this bus...
 113         virtual void getDeviceAddressRanges(AddrRangeList &resp,
 114                                             bool &snoop)
 115         { bus->addressRanges(resp, snoop, id); }
 116
 117         // Ask the bus to ask everyone on the bus what their block size is and
 118         // take the max of it. This might need to be changed a bit if we ever
 119         // support multiple block sizes.
 120         virtual int deviceBlockSize()
 121         { return bus->findBlockSize(id); }
 122
 123     };
 124
 125     class BusFreeEvent : public Event
 126     {
 127         Bus * bus;
 128
 129       public:
 130         BusFreeEvent(Bus * _bus);
 131         void process();
 132         const char *description();
 133     };
 134
 135     /** a globally unique id for this bus. */
 136     int busId;
 137     /** the clock speed for the bus */
 138     int clock;
 139     /** the width of the bus in bytes */
 140     int width;
 141     /** the next tick at which the bus will be idle */
 142     Tick tickNextIdle;
 143
 144     Event * drainEvent;
 145
 146
 147     static const int defaultId = -3; //Make it unique from Broadcast
 148
 149     typedef range_map<Addr,int>::iterator PortIter;
 150     range_map<Addr, int> portMap;
 151
 152     AddrRangeList defaultRange;
 153
 154     typedef std::vector<BusPort*>::iterator SnoopIter;
 155     std::vector<BusPort*> snoopPorts;
 156
 157     /** Function called by the port when the bus is recieving a Timing
 158       transaction.*/
 159     bool recvTiming(PacketPtr pkt);
 160
 161     /** Function called by the port when the bus is recieving a Atomic
 162       transaction.*/
 163     Tick recvAtomic(PacketPtr pkt);
 164
 165     /** Function called by the port when the bus is recieving a Functional
 166         transaction.*/
 167     void recvFunctional(PacketPtr pkt);
 168
 169     /** Timing function called by port when it is once again able to process
 170      * requests. */
 171     void recvRetry(int id);
 172
 173     /** Function called by the port when the bus is recieving a status change.*/
 174     void recvStatusChange(Port::Status status, int id);
 175
 176     /** Find which port connected to this bus (if any) should be given a packet
 177      * with this address.
 178      * @param addr Address to find port for.
 179      * @param id Id of the port this packet was received from (to prevent
 180      *             loops)
 181      * @return pointer to port that the packet should be sent out of.
 182      */
 183     Port *findPort(Addr addr, int id);
 184
 185     /** Snoop all relevant ports atomicly. */
 186     Tick atomicSnoop(PacketPtr pkt, Port* responder);
 187
 188     /** Snoop all relevant ports functionally. */
 189     void functionalSnoop(PacketPtr pkt, Port *responder);
 190
 191     /** Call snoop on caches, be sure to set SNOOP_COMMIT bit if you want
 192      * the snoop to happen
 193      * @return True if succeds.
 194      */
 195     bool timingSnoop(PacketPtr pkt, Port *responder);
 196
 197     /** Process address range request.
 198      * @param resp addresses that we can respond to
 199      * @param snoop addresses that we would like to snoop
 200      * @param id ide of the busport that made the request.
 201      */
 202     void addressRanges(AddrRangeList &resp, bool &snoop, int id);
 203
 204     /** Occupy the bus with transmitting the packet pkt */
 205     void occupyBus(PacketPtr pkt);
 206
 207     /** Ask everyone on the bus what their size is
 208      * @param id id of the busport that made the request
 209      * @return the max of all the sizes
 210      */
 211     int findBlockSize(int id);
 212
 213     BusFreeEvent busIdle;
 214
 215     bool inRetry;
 216
 217     /** max number of bus ids we've handed out so far */
 218     short maxId;
 219
 220     /** An array of pointers to the peer port interfaces
 221         connected to this bus.*/
 222     m5::hash_map<short,BusPort*> interfaces;
 223
 224     /** An array of pointers to ports that retry should be called on because the
 225      * original send failed for whatever reason.*/
 226     std::list<BusPort*> retryList;
 227
 228     void addToRetryList(BusPort * port)
 229     {
 230         if (!inRetry) {
 231             // The device wasn't retrying a packet, or wasn't at an appropriate
 232             // time.
 233             assert(!port->onRetryList());
 234             port->onRetryList(true);
 235             retryList.push_back(port);
 236         } else {
 237             if (port->onRetryList()) {
 238                 // The device was retrying a packet. It didn't work, so we'll leave
 239                 // it at the head of the retry list.
 240                 assert(port == retryList.front());
 241                 inRetry = false;
 242             }
 243             else {
 244                 port->onRetryList(true);
 245                 retryList.push_back(port);
 246             }
 247         }
 248     }
 249
 250     /** Port that handles requests that don't match any of the interfaces.*/
 251     BusPort *defaultPort;
 252
 253     BusPort *funcPort;
 254     int funcPortId;
 255
 256     /** Has the user specified their own default responder? */
 257     bool responderSet;
 258
 259     int defaultBlockSize;
 260     int cachedBlockSize;
 261     bool cachedBlockSizeValid;
 262
 263   public:
 264
 265     /** A function used to return the port associated with this bus object. */
 266     virtual Port *getPort(const std::string &if_name, int idx = -1);
 267     virtual void deletePortRefs(Port *p);
 268
 269     virtual void init();
 270
 271     unsigned int drain(Event *de);
 272
 273     Bus(const std::string &n, int bus_id, int _clock, int _width,
 274         bool responder_set, int dflt_blk_size)
 275         : MemObject(n), busId(bus_id), clock(_clock), width(_width),
 276           tickNextIdle(0), drainEvent(NULL), busIdle(this), inRetry(false),
 277           maxId(0), defaultPort(NULL), funcPort(NULL), funcPortId(-4),
 278           responderSet(responder_set), defaultBlockSize(dflt_blk_size),
 279           cachedBlockSize(0), cachedBlockSizeValid(false)
 280     {
 281         //Both the width and clock period must be positive
 282         if (width <= 0)
 283             fatal("Bus width must be positive\n");
 284         if (clock <= 0)
 285             fatal("Bus clock period must be positive\n");
 286     }
 287
 288 };
 289
 290 #endif //__MEM_BUS_HH__