src/mem/bus.cc

   1 /*
   2  * Copyright (c) 2006 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: Ali Saidi
  29  */
  30
  31 /**
  32  * @file
  33  * Definition of a bus object.
  34  */
  35
  36
  37 #include "base/misc.hh"
  38 #include "base/trace.hh"
  39 #include "mem/bus.hh"
  40 #include "sim/builder.hh"
  41
  42 Port *
  43 Bus::getPort(const std::string &if_name, int idx)
  44 {
  45     if (if_name == "default")
  46         if (defaultPort == NULL) {
  47             defaultPort = new BusPort(csprintf("%s-default",name()), this,
  48                     defaultId);
  49             return defaultPort;
  50         } else
  51             fatal("Default port already set\n");
  52
  53     // if_name ignored?  forced to be empty?
  54     int id = interfaces.size();
  55     BusPort *bp = new BusPort(csprintf("%s-p%d", name(), id), this, id);
  56     interfaces.push_back(bp);
  57     return bp;
  58 }
  59
  60 /** Get the ranges of anyone other buses that we are connected to. */
  61 void
  62 Bus::init()
  63 {
  64     std::vector<Port*>::iterator intIter;
  65
  66     for (intIter = interfaces.begin(); intIter != interfaces.end(); intIter++)
  67         (*intIter)->sendStatusChange(Port::RangeChange);
  68 }
  69
  70
  71 /** Function called by the port when the bus is receiving a Timing
  72  * transaction.*/
  73 bool
  74 Bus::recvTiming(Packet *pkt)
  75 {
  76     Port *port;
  77     DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
  78             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
  79
  80     short dest = pkt->getDest();
  81     if (dest == Packet::Broadcast) {
  82         if (timingSnoop(pkt))
  83         {
  84             pkt->flags |= SNOOP_COMMIT;
  85             bool success = timingSnoop(pkt);
  86             assert(success);
  87             if (pkt->flags & SATISFIED) {
  88                 //Cache-Cache transfer occuring
  89                 return true;
  90             }
  91             port = findPort(pkt->getAddr(), pkt->getSrc());
  92         }
  93         else
  94         {
  95             //Snoop didn't succeed
  96             retryList.push_back(interfaces[pkt->getSrc()]);
  97             return false;
  98         }
  99     } else {
 100         assert(dest >= 0 && dest < interfaces.size());
 101         assert(dest != pkt->getSrc()); // catch infinite loops
 102         port = interfaces[dest];
 103     }
 104     if (port->sendTiming(pkt))  {
 105         // packet was successfully sent, just return true.
 106         return true;
 107     }
 108
 109     // packet not successfully sent
 110     retryList.push_back(interfaces[pkt->getSrc()]);
 111     return false;
 112 }
 113
 114 void
 115 Bus::recvRetry(int id)
 116 {
 117     // Go through all the elements on the list calling sendRetry on each
 118     // This is not very efficient at all but it works. Ultimately we should end
 119     // up with something that is more intelligent.
 120     int initialSize = retryList.size();
 121     int i;
 122     Port *p;
 123
 124     for (i = 0; i < initialSize; i++) {
 125         assert(retryList.size() > 0);
 126         p = retryList.front();
 127         retryList.pop_front();
 128         p->sendRetry();
 129     }
 130 }
 131
 132
 133 Port *
 134 Bus::findPort(Addr addr, int id)
 135 {
 136     /* An interval tree would be a better way to do this. --ali. */
 137     int dest_id = -1;
 138     int i = 0;
 139     bool found = false;
 140     AddrRangeIter iter;
 141
 142     while (i < portList.size() && !found)
 143     {
 144         if (portList[i].range == addr) {
 145             dest_id = portList[i].portId;
 146             found = true;
 147             DPRINTF(Bus, "  found addr %#llx on device %d\n", addr, dest_id);
 148         }
 149         i++;
 150     }
 151
 152     // Check if this matches the default range
 153     if (dest_id == -1) {
 154         for (iter = defaultRange.begin(); iter != defaultRange.end(); iter++) {
 155             if (*iter == addr) {
 156                 DPRINTF(Bus, "  found addr %#llx on default\n", addr);
 157                 return defaultPort;
 158             }
 159         }
 160         panic("Unable to find destination for addr: %#llx", addr);
 161     }
 162
 163
 164     // we shouldn't be sending this back to where it came from
 165     assert(dest_id != id);
 166
 167     return interfaces[dest_id];
 168 }
 169
 170 std::vector<int>
 171 Bus::findSnoopPorts(Addr addr, int id)
 172 {
 173     int i = 0;
 174     AddrRangeIter iter;
 175     std::vector<int> ports;
 176
 177     while (i < portSnoopList.size())
 178     {
 179         if (portSnoopList[i].range == addr && portSnoopList[i].portId != id) {
 180             //Careful  to not overlap ranges
 181             //or snoop will be called more than once on the port
 182             ports.push_back(portSnoopList[i].portId);
 183             DPRINTF(Bus, "  found snoop addr %#llx on device%d\n", addr,
 184                     portSnoopList[i].portId);
 185         }
 186         i++;
 187     }
 188     return ports;
 189 }
 190
 191 void
 192 Bus::atomicSnoop(Packet *pkt)
 193 {
 194     std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
 195
 196     while (!ports.empty())
 197     {
 198         interfaces[ports.back()]->sendAtomic(pkt);
 199         ports.pop_back();
 200     }
 201 }
 202
 203 bool
 204 Bus::timingSnoop(Packet *pkt)
 205 {
 206     std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
 207     bool success = true;
 208
 209     while (!ports.empty() && success)
 210     {
 211         success = interfaces[ports.back()]->sendTiming(pkt);
 212         ports.pop_back();
 213     }
 214
 215     return success;
 216 }
 217
 218
 219 /** Function called by the port when the bus is receiving a Atomic
 220  * transaction.*/
 221 Tick
 222 Bus::recvAtomic(Packet *pkt)
 223 {
 224     DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
 225             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 226     assert(pkt->getDest() == Packet::Broadcast);
 227     atomicSnoop(pkt);
 228     return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
 229 }
 230
 231 /** Function called by the port when the bus is receiving a Functional
 232  * transaction.*/
 233 void
 234 Bus::recvFunctional(Packet *pkt)
 235 {
 236     DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
 237             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 238     assert(pkt->getDest() == Packet::Broadcast);
 239     atomicSnoop(pkt);
 240     findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
 241 }
 242
 243 /** Function called by the port when the bus is receiving a status change.*/
 244 void
 245 Bus::recvStatusChange(Port::Status status, int id)
 246 {
 247     AddrRangeList ranges;
 248     AddrRangeList snoops;
 249     int x;
 250     AddrRangeIter iter;
 251
 252     assert(status == Port::RangeChange &&
 253            "The other statuses need to be implemented.");
 254
 255     DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
 256
 257     if (id == defaultId) {
 258         defaultRange.clear();
 259         defaultPort->getPeerAddressRanges(ranges, snoops);
 260         assert(snoops.size() == 0);
 261         for(iter = ranges.begin(); iter != ranges.end(); iter++) {
 262             defaultRange.push_back(*iter);
 263             DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n",
 264                     iter->start, iter->end);
 265         }
 266     } else {
 267
 268         assert((id < interfaces.size() && id >= 0) || id == -1);
 269         Port *port = interfaces[id];
 270         std::vector<DevMap>::iterator portIter;
 271         std::vector<DevMap>::iterator snoopIter;
 272
 273         // Clean out any previously existent ids
 274         for (portIter = portList.begin(); portIter != portList.end(); ) {
 275             if (portIter->portId == id)
 276                 portIter = portList.erase(portIter);
 277             else
 278                 portIter++;
 279         }
 280
 281         for (snoopIter = portSnoopList.begin(); snoopIter != portSnoopList.end(); ) {
 282             if (snoopIter->portId == id)
 283                 snoopIter = portSnoopList.erase(snoopIter);
 284             else
 285                 snoopIter++;
 286         }
 287
 288         port->getPeerAddressRanges(ranges, snoops);
 289
 290         for(iter = snoops.begin(); iter != snoops.end(); iter++) {
 291             DevMap dm;
 292             dm.portId = id;
 293             dm.range = *iter;
 294
 295             DPRINTF(BusAddrRanges, "Adding snoop range %#llx - %#llx for id %d\n",
 296                     dm.range.start, dm.range.end, id);
 297             portSnoopList.push_back(dm);
 298         }
 299
 300         for(iter = ranges.begin(); iter != ranges.end(); iter++) {
 301             DevMap dm;
 302             dm.portId = id;
 303             dm.range = *iter;
 304
 305             DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n",
 306                     dm.range.start, dm.range.end, id);
 307             portList.push_back(dm);
 308         }
 309     }
 310     DPRINTF(MMU, "port list has %d entries\n", portList.size());
 311
 312     // tell all our peers that our address range has changed.
 313     // Don't tell the device that caused this change, it already knows
 314     for (x = 0; x < interfaces.size(); x++)
 315         if (x != id)
 316             interfaces[x]->sendStatusChange(Port::RangeChange);
 317
 318     if (id != defaultId && defaultPort)
 319         defaultPort->sendStatusChange(Port::RangeChange);
 320 }
 321
 322 void
 323 Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
 324 {
 325     std::vector<DevMap>::iterator portIter;
 326     AddrRangeIter dflt_iter;
 327     bool subset;
 328
 329     resp.clear();
 330     snoop.clear();
 331
 332     DPRINTF(BusAddrRanges, "received address range request, returning:\n");
 333
 334     for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
 335             dflt_iter++) {
 336         resp.push_back(*dflt_iter);
 337         DPRINTF(BusAddrRanges, "  -- %#llx : %#llx\n",dflt_iter->start,
 338                 dflt_iter->end);
 339     }
 340     for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
 341         subset = false;
 342         for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
 343                 dflt_iter++) {
 344             if ((portIter->range.start < dflt_iter->start &&
 345                 portIter->range.end >= dflt_iter->start) ||
 346                (portIter->range.start < dflt_iter->end &&
 347                 portIter->range.end >= dflt_iter->end))
 348                 fatal("Devices can not set ranges that itersect the default set\
 349                         but are not a subset of the default set.\n");
 350             if (portIter->range.start >= dflt_iter->start &&
 351                 portIter->range.end <= dflt_iter->end) {
 352                 subset = true;
 353                 DPRINTF(BusAddrRanges, "  -- %#llx : %#llx is a SUBSET\n",
 354                     portIter->range.start, portIter->range.end);
 355             }
 356         }
 357         if (portIter->portId != id && !subset) {
 358             resp.push_back(portIter->range);
 359             DPRINTF(BusAddrRanges, "  -- %#llx : %#llx\n",
 360                     portIter->range.start, portIter->range.end);
 361         }
 362     }
 363 }
 364
 365 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
 366
 367     Param<int> bus_id;
 368
 369 END_DECLARE_SIM_OBJECT_PARAMS(Bus)
 370
 371 BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
 372     INIT_PARAM(bus_id, "a globally unique bus id")
 373 END_INIT_SIM_OBJECT_PARAMS(Bus)
 374
 375 CREATE_SIM_OBJECT(Bus)
 376 {
 377     return new Bus(getInstanceName(), bus_id);
 378 }
 379
 380 REGISTER_SIM_OBJECT("Bus", Bus)