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 ( timingSnoopPhase1(pkt) )
  83         {
  84             timingSnoopPhase2(pkt);
  85             port = findPort(pkt->getAddr(), pkt->getSrc());
  86         }
  87         else
  88         {
  89             //Snoop didn't succeed
  90             retryList.push_back(interfaces[pkt->getSrc()]);
  91             return false;
  92         }
  93     } else {
  94         assert(dest >= 0 && dest < interfaces.size());
  95         assert(dest != pkt->getSrc()); // catch infinite loops
  96         port = interfaces[dest];
  97     }
  98     if (port->sendTiming(pkt))  {
  99         // packet was successfully sent, just return true.
 100         return true;
 101     }
 102
 103     // packet not successfully sent
 104     retryList.push_back(interfaces[pkt->getSrc()]);
 105     return false;
 106 }
 107
 108 void
 109 Bus::recvRetry(int id)
 110 {
 111     // Go through all the elements on the list calling sendRetry on each
 112     // This is not very efficient at all but it works. Ultimately we should end
 113     // up with something that is more intelligent.
 114     int initialSize = retryList.size();
 115     int i;
 116     Port *p;
 117
 118     for (i = 0; i < initialSize; i++) {
 119         assert(retryList.size() > 0);
 120         p = retryList.front();
 121         retryList.pop_front();
 122         p->sendRetry();
 123     }
 124 }
 125
 126
 127 Port *
 128 Bus::findPort(Addr addr, int id)
 129 {
 130     /* An interval tree would be a better way to do this. --ali. */
 131     int dest_id = -1;
 132     int i = 0;
 133     bool found = false;
 134     AddrRangeIter iter;
 135
 136     while (i < portList.size() && !found)
 137     {
 138         if (portList[i].range == addr) {
 139             dest_id = portList[i].portId;
 140             found = true;
 141             DPRINTF(Bus, "  found addr %#llx on device %d\n", addr, dest_id);
 142         }
 143         i++;
 144     }
 145
 146     // Check if this matches the default range
 147     if (dest_id == -1) {
 148         for (iter = defaultRange.begin(); iter != defaultRange.end(); iter++) {
 149             if (*iter == addr) {
 150                 DPRINTF(Bus, "  found addr %#llx on default\n", addr);
 151                 return defaultPort;
 152             }
 153         }
 154         panic("Unable to find destination for addr: %#llx", addr);
 155     }
 156
 157
 158     // we shouldn't be sending this back to where it came from
 159     assert(dest_id != id);
 160
 161     return interfaces[dest_id];
 162 }
 163
 164 std::vector<int>
 165 Bus::findSnoopPorts(Addr addr, int id)
 166 {
 167     int i = 0;
 168     AddrRangeIter iter;
 169     std::vector<int> ports;
 170
 171     while (i < portSnoopList.size())
 172     {
 173         if (portSnoopList[i].range == addr && portSnoopList[i].portId != id) {
 174             //Careful  to not overlap ranges
 175             //or snoop will be called more than once on the port
 176             ports.push_back(portSnoopList[i].portId);
 177             DPRINTF(Bus, "  found snoop addr %#llx on device%d\n", addr,
 178                     portSnoopList[i].portId);
 179         }
 180         i++;
 181     }
 182     return ports;
 183 }
 184
 185 void
 186 Bus::atomicSnoop(Packet *pkt)
 187 {
 188     std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
 189
 190     while (!ports.empty())
 191     {
 192         interfaces[ports.back()]->sendAtomic(pkt);
 193         ports.pop_back();
 194     }
 195 }
 196
 197 bool
 198 Bus::timingSnoopPhase1(Packet *pkt)
 199 {
 200     std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
 201     bool success = true;
 202
 203     while (!ports.empty() && success)
 204     {
 205         snoopCallbacks.push_back(ports.back());
 206         success = interfaces[ports.back()]->sendTiming(pkt);
 207         ports.pop_back();
 208     }
 209     if (!success)
 210     {
 211         while (!snoopCallbacks.empty())
 212         {
 213             interfaces[snoopCallbacks.back()]->sendStatusChange(Port::SnoopSquash);
 214             snoopCallbacks.pop_back();
 215         }
 216         return false;
 217     }
 218     return true;
 219 }
 220
 221 void
 222 Bus::timingSnoopPhase2(Packet *pkt)
 223 {
 224     bool success;
 225     pkt->flags |= SNOOP_COMMIT;
 226     while (!snoopCallbacks.empty())
 227     {
 228         success = interfaces[snoopCallbacks.back()]->sendTiming(pkt);
 229         //We should not fail on snoop callbacks
 230         assert(success);
 231         snoopCallbacks.pop_back();
 232     }
 233 }
 234
 235 /** Function called by the port when the bus is receiving a Atomic
 236  * transaction.*/
 237 Tick
 238 Bus::recvAtomic(Packet *pkt)
 239 {
 240     DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
 241             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 242     assert(pkt->getDest() == Packet::Broadcast);
 243     atomicSnoop(pkt);
 244     return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
 245 }
 246
 247 /** Function called by the port when the bus is receiving a Functional
 248  * transaction.*/
 249 void
 250 Bus::recvFunctional(Packet *pkt)
 251 {
 252     DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
 253             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 254     assert(pkt->getDest() == Packet::Broadcast);
 255     atomicSnoop(pkt);
 256     findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
 257 }
 258
 259 /** Function called by the port when the bus is receiving a status change.*/
 260 void
 261 Bus::recvStatusChange(Port::Status status, int id)
 262 {
 263     AddrRangeList ranges;
 264     AddrRangeList snoops;
 265     int x;
 266     AddrRangeIter iter;
 267
 268     assert(status == Port::RangeChange &&
 269            "The other statuses need to be implemented.");
 270
 271     DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
 272
 273     if (id == defaultId) {
 274         defaultRange.clear();
 275         defaultPort->getPeerAddressRanges(ranges, snoops);
 276         assert(snoops.size() == 0);
 277         for(iter = ranges.begin(); iter != ranges.end(); iter++) {
 278             defaultRange.push_back(*iter);
 279             DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n",
 280                     iter->start, iter->end);
 281         }
 282     } else {
 283
 284         assert((id < interfaces.size() && id >= 0) || id == -1);
 285         Port *port = interfaces[id];
 286         std::vector<DevMap>::iterator portIter;
 287         std::vector<DevMap>::iterator snoopIter;
 288
 289         // Clean out any previously existent ids
 290         for (portIter = portList.begin(); portIter != portList.end(); ) {
 291             if (portIter->portId == id)
 292                 portIter = portList.erase(portIter);
 293             else
 294                 portIter++;
 295         }
 296
 297         for (snoopIter = portSnoopList.begin(); snoopIter != portSnoopList.end(); ) {
 298             if (snoopIter->portId == id)
 299                 snoopIter = portSnoopList.erase(snoopIter);
 300             else
 301                 snoopIter++;
 302         }
 303
 304         port->getPeerAddressRanges(ranges, snoops);
 305
 306         for(iter = snoops.begin(); iter != snoops.end(); iter++) {
 307             DevMap dm;
 308             dm.portId = id;
 309             dm.range = *iter;
 310
 311             DPRINTF(BusAddrRanges, "Adding snoop range %#llx - %#llx for id %d\n",
 312                     dm.range.start, dm.range.end, id);
 313             portSnoopList.push_back(dm);
 314         }
 315
 316         for(iter = ranges.begin(); iter != ranges.end(); iter++) {
 317             DevMap dm;
 318             dm.portId = id;
 319             dm.range = *iter;
 320
 321             DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n",
 322                     dm.range.start, dm.range.end, id);
 323             portList.push_back(dm);
 324         }
 325     }
 326     DPRINTF(MMU, "port list has %d entries\n", portList.size());
 327
 328     // tell all our peers that our address range has changed.
 329     // Don't tell the device that caused this change, it already knows
 330     for (x = 0; x < interfaces.size(); x++)
 331         if (x != id)
 332             interfaces[x]->sendStatusChange(Port::RangeChange);
 333
 334     if (id != defaultId && defaultPort)
 335         defaultPort->sendStatusChange(Port::RangeChange);
 336 }
 337
 338 void
 339 Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
 340 {
 341     std::vector<DevMap>::iterator portIter;
 342     AddrRangeIter dflt_iter;
 343     bool subset;
 344
 345     resp.clear();
 346     snoop.clear();
 347
 348     DPRINTF(BusAddrRanges, "received address range request, returning:\n");
 349
 350     for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
 351             dflt_iter++) {
 352         resp.push_back(*dflt_iter);
 353         DPRINTF(BusAddrRanges, "  -- %#llx : %#llx\n",dflt_iter->start,
 354                 dflt_iter->end);
 355     }
 356     for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
 357         subset = false;
 358         for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
 359                 dflt_iter++) {
 360             if ((portIter->range.start < dflt_iter->start &&
 361                 portIter->range.end >= dflt_iter->start) ||
 362                (portIter->range.start < dflt_iter->end &&
 363                 portIter->range.end >= dflt_iter->end))
 364                 fatal("Devices can not set ranges that itersect the default set\
 365                         but are not a subset of the default set.\n");
 366             if (portIter->range.start >= dflt_iter->start &&
 367                 portIter->range.end <= dflt_iter->end) {
 368                 subset = true;
 369                 DPRINTF(BusAddrRanges, "  -- %#llx : %#llx is a SUBSET\n",
 370                     portIter->range.start, portIter->range.end);
 371             }
 372         }
 373         if (portIter->portId != id && !subset) {
 374             resp.push_back(portIter->range);
 375             DPRINTF(BusAddrRanges, "  -- %#llx : %#llx\n",
 376                     portIter->range.start, portIter->range.end);
 377         }
 378     }
 379 }
 380
 381 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
 382
 383     Param<int> bus_id;
 384
 385 END_DECLARE_SIM_OBJECT_PARAMS(Bus)
 386
 387 BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
 388     INIT_PARAM(bus_id, "a globally unique bus id")
 389 END_INIT_SIM_OBJECT_PARAMS(Bus)
 390
 391 CREATE_SIM_OBJECT(Bus)
 392 {
 393     return new Bus(getInstanceName(), bus_id);
 394 }
 395
 396 REGISTER_SIM_OBJECT("Bus", Bus)