ab44417282
src/mem/bus.cc:
Put back the check to see if the bus is busy. Also, populate the fields in the packet to indicate when the first word and the entire packet will be delivered.
src/mem/bus.hh:
Remove the occupyBus function.
src/mem/packet.hh:
Added fields to the packet to indicate when the first chunk of a packet arrives, and when the entire packet arrives.
--HG--
extra : convert_revision : cfc7670a33913d48a04d02c6d2448290a51f2d3c
477 lines
15 KiB
C++
477 lines
15 KiB
C++
/*
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* Copyright (c) 2006 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Ali Saidi
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*/
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/**
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* @file
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* Definition of a bus object.
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*/
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#include "base/misc.hh"
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#include "base/trace.hh"
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#include "mem/bus.hh"
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#include "sim/builder.hh"
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Port *
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Bus::getPort(const std::string &if_name, int idx)
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{
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if (if_name == "default")
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if (defaultPort == NULL) {
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defaultPort = new BusPort(csprintf("%s-default",name()), this,
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defaultId);
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return defaultPort;
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} else
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fatal("Default port already set\n");
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// if_name ignored? forced to be empty?
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int id = interfaces.size();
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BusPort *bp = new BusPort(csprintf("%s-p%d", name(), id), this, id);
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interfaces.push_back(bp);
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return bp;
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}
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/** Get the ranges of anyone other buses that we are connected to. */
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void
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Bus::init()
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{
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std::vector<Port*>::iterator intIter;
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for (intIter = interfaces.begin(); intIter != interfaces.end(); intIter++)
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(*intIter)->sendStatusChange(Port::RangeChange);
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}
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Bus::BusFreeEvent::BusFreeEvent(Bus *_bus) : Event(&mainEventQueue), bus(_bus)
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{
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assert(!scheduled());
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}
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void Bus::BusFreeEvent::process()
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{
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bus->recvRetry(0);
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}
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const char * Bus::BusFreeEvent::description()
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{
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return "bus became available";
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}
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/** Function called by the port when the bus is receiving a Timing
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* transaction.*/
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bool
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Bus::recvTiming(Packet *pkt)
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{
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Port *port;
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DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
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pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
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Port *pktPort = interfaces[pkt->getSrc()];
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// If the bus is busy, or other devices are in line ahead of the current
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// one, put this device on the retry list.
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if (tickNextIdle > curTick ||
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(retryList.size() && pktPort != retryingPort)) {
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addToRetryList(pktPort);
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return false;
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}
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short dest = pkt->getDest();
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if (dest == Packet::Broadcast) {
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if (timingSnoop(pkt)) {
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pkt->flags |= SNOOP_COMMIT;
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bool success = timingSnoop(pkt);
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assert(success);
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if (pkt->flags & SATISFIED) {
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//Cache-Cache transfer occuring
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if (retryingPort) {
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retryList.pop_front();
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retryingPort = NULL;
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}
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return true;
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}
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port = findPort(pkt->getAddr(), pkt->getSrc());
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} else {
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//Snoop didn't succeed
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addToRetryList(pktPort);
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return false;
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}
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} else {
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assert(dest >= 0 && dest < interfaces.size());
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assert(dest != pkt->getSrc()); // catch infinite loops
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port = interfaces[dest];
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}
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//Bring tickNextIdle up to the present tick
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//There is some potential ambiguity where a cycle starts, which might make
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//a difference when devices are acting right around a cycle boundary. Using
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//a < allows things which happen exactly on a cycle boundary to take up only
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//the following cycle. Anthing that happens later will have to "wait" for
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//the end of that cycle, and then start using the bus after that.
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while (tickNextIdle < curTick)
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tickNextIdle += clock;
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// The packet will be sent. Figure out how long it occupies the bus, and
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// how much of that time is for the first "word", aka bus width.
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int numCycles = 0;
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// Requests need one cycle to send an address
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if (pkt->isRequest())
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numCycles++;
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else if (pkt->isResponse() || pkt->hasData()) {
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// If a packet has data, it needs ceil(size/width) cycles to send it
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// We're using the "adding instead of dividing" trick again here
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if (pkt->hasData()) {
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int dataSize = pkt->getSize();
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for (int transmitted = 0; transmitted < dataSize;
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transmitted += width) {
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numCycles++;
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}
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} else {
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// If the packet didn't have data, it must have been a response.
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// Those use the bus for one cycle to send their data.
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numCycles++;
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}
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}
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// The first word will be delivered after the current tick, the delivery
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// of the address if any, and one bus cycle to deliver the data
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pkt->firstWordTime =
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tickNextIdle +
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pkt->isRequest() ? clock : 0 +
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clock;
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//Advance it numCycles bus cycles.
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//XXX Should this use the repeated addition trick as well?
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tickNextIdle += (numCycles * clock);
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if (!busIdle.scheduled()) {
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busIdle.schedule(tickNextIdle);
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} else {
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busIdle.reschedule(tickNextIdle);
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}
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DPRINTF(Bus, "The bus is now occupied from tick %d to %d\n",
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curTick, tickNextIdle);
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// The bus will become idle once the current packet is delivered.
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pkt->finishTime = tickNextIdle;
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if (port->sendTiming(pkt)) {
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// Packet was successfully sent. Return true.
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// Also take care of retries
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if (retryingPort) {
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retryList.pop_front();
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retryingPort = NULL;
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}
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return true;
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}
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// Packet not successfully sent. Leave or put it on the retry list.
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addToRetryList(pktPort);
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return false;
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}
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void
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Bus::recvRetry(int id)
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{
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// If there's anything waiting...
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if (retryList.size()) {
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retryingPort = retryList.front();
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retryingPort->sendRetry();
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// If the retryingPort pointer isn't null, sendTiming wasn't called
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if (retryingPort) {
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warn("sendRetry didn't call sendTiming\n");
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retryList.pop_front();
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retryingPort = NULL;
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}
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}
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}
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Port *
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Bus::findPort(Addr addr, int id)
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{
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/* An interval tree would be a better way to do this. --ali. */
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int dest_id = -1;
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int i = 0;
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bool found = false;
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AddrRangeIter iter;
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while (i < portList.size() && !found)
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{
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if (portList[i].range == addr) {
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dest_id = portList[i].portId;
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found = true;
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DPRINTF(Bus, " found addr %#llx on device %d\n", addr, dest_id);
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}
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i++;
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}
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// Check if this matches the default range
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if (dest_id == -1) {
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for (iter = defaultRange.begin(); iter != defaultRange.end(); iter++) {
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if (*iter == addr) {
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DPRINTF(Bus, " found addr %#llx on default\n", addr);
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return defaultPort;
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}
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}
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panic("Unable to find destination for addr: %#llx", addr);
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}
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// we shouldn't be sending this back to where it came from
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assert(dest_id != id);
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return interfaces[dest_id];
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}
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std::vector<int>
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Bus::findSnoopPorts(Addr addr, int id)
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{
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int i = 0;
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AddrRangeIter iter;
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std::vector<int> ports;
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while (i < portSnoopList.size())
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{
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if (portSnoopList[i].range == addr && portSnoopList[i].portId != id) {
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//Careful to not overlap ranges
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//or snoop will be called more than once on the port
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ports.push_back(portSnoopList[i].portId);
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DPRINTF(Bus, " found snoop addr %#llx on device%d\n", addr,
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portSnoopList[i].portId);
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}
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i++;
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}
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return ports;
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}
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void
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Bus::atomicSnoop(Packet *pkt)
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{
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std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
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while (!ports.empty())
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{
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interfaces[ports.back()]->sendAtomic(pkt);
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ports.pop_back();
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}
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}
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void
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Bus::functionalSnoop(Packet *pkt)
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{
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std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
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while (!ports.empty())
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{
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interfaces[ports.back()]->sendFunctional(pkt);
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ports.pop_back();
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}
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}
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bool
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Bus::timingSnoop(Packet *pkt)
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{
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std::vector<int> ports = findSnoopPorts(pkt->getAddr(), pkt->getSrc());
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bool success = true;
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while (!ports.empty() && success)
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{
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success = interfaces[ports.back()]->sendTiming(pkt);
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ports.pop_back();
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}
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return success;
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}
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/** Function called by the port when the bus is receiving a Atomic
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* transaction.*/
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Tick
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Bus::recvAtomic(Packet *pkt)
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{
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DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
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pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
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assert(pkt->getDest() == Packet::Broadcast);
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atomicSnoop(pkt);
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return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
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}
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/** Function called by the port when the bus is receiving a Functional
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* transaction.*/
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void
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Bus::recvFunctional(Packet *pkt)
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{
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DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
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pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
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assert(pkt->getDest() == Packet::Broadcast);
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functionalSnoop(pkt);
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findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
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}
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/** Function called by the port when the bus is receiving a status change.*/
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void
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Bus::recvStatusChange(Port::Status status, int id)
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{
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AddrRangeList ranges;
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AddrRangeList snoops;
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int x;
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AddrRangeIter iter;
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assert(status == Port::RangeChange &&
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"The other statuses need to be implemented.");
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DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
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if (id == defaultId) {
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defaultRange.clear();
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defaultPort->getPeerAddressRanges(ranges, snoops);
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assert(snoops.size() == 0);
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for(iter = ranges.begin(); iter != ranges.end(); iter++) {
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defaultRange.push_back(*iter);
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DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for default range\n",
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iter->start, iter->end);
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}
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} else {
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assert((id < interfaces.size() && id >= 0) || id == -1);
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Port *port = interfaces[id];
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std::vector<DevMap>::iterator portIter;
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std::vector<DevMap>::iterator snoopIter;
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// Clean out any previously existent ids
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for (portIter = portList.begin(); portIter != portList.end(); ) {
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if (portIter->portId == id)
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portIter = portList.erase(portIter);
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else
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portIter++;
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}
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for (snoopIter = portSnoopList.begin(); snoopIter != portSnoopList.end(); ) {
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if (snoopIter->portId == id)
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snoopIter = portSnoopList.erase(snoopIter);
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else
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snoopIter++;
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}
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port->getPeerAddressRanges(ranges, snoops);
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for(iter = snoops.begin(); iter != snoops.end(); iter++) {
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DevMap dm;
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dm.portId = id;
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dm.range = *iter;
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DPRINTF(BusAddrRanges, "Adding snoop range %#llx - %#llx for id %d\n",
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dm.range.start, dm.range.end, id);
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portSnoopList.push_back(dm);
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}
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for(iter = ranges.begin(); iter != ranges.end(); iter++) {
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DevMap dm;
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dm.portId = id;
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dm.range = *iter;
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DPRINTF(BusAddrRanges, "Adding range %#llx - %#llx for id %d\n",
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dm.range.start, dm.range.end, id);
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portList.push_back(dm);
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}
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}
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DPRINTF(MMU, "port list has %d entries\n", portList.size());
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// tell all our peers that our address range has changed.
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// Don't tell the device that caused this change, it already knows
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for (x = 0; x < interfaces.size(); x++)
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if (x != id)
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interfaces[x]->sendStatusChange(Port::RangeChange);
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if (id != defaultId && defaultPort)
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defaultPort->sendStatusChange(Port::RangeChange);
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}
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void
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Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
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{
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std::vector<DevMap>::iterator portIter;
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AddrRangeIter dflt_iter;
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bool subset;
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resp.clear();
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snoop.clear();
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DPRINTF(BusAddrRanges, "received address range request, returning:\n");
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for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
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dflt_iter++) {
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resp.push_back(*dflt_iter);
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DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n",dflt_iter->start,
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dflt_iter->end);
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}
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for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
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subset = false;
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for (dflt_iter = defaultRange.begin(); dflt_iter != defaultRange.end();
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dflt_iter++) {
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if ((portIter->range.start < dflt_iter->start &&
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portIter->range.end >= dflt_iter->start) ||
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(portIter->range.start < dflt_iter->end &&
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portIter->range.end >= dflt_iter->end))
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fatal("Devices can not set ranges that itersect the default set\
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but are not a subset of the default set.\n");
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if (portIter->range.start >= dflt_iter->start &&
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portIter->range.end <= dflt_iter->end) {
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subset = true;
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DPRINTF(BusAddrRanges, " -- %#llx : %#llx is a SUBSET\n",
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portIter->range.start, portIter->range.end);
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}
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}
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if (portIter->portId != id && !subset) {
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resp.push_back(portIter->range);
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DPRINTF(BusAddrRanges, " -- %#llx : %#llx\n",
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portIter->range.start, portIter->range.end);
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}
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}
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}
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BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
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Param<int> bus_id;
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Param<int> clock;
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Param<int> width;
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END_DECLARE_SIM_OBJECT_PARAMS(Bus)
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BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
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INIT_PARAM(bus_id, "a globally unique bus id"),
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INIT_PARAM(clock, "bus clock speed"),
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INIT_PARAM(width, "width of the bus (bits)")
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END_INIT_SIM_OBJECT_PARAMS(Bus)
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CREATE_SIM_OBJECT(Bus)
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{
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return new Bus(getInstanceName(), bus_id, clock, width);
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}
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REGISTER_SIM_OBJECT("Bus", Bus)
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