860155a5fc
This patch adds a check to ensure that the delay incurred by the bus is not simply disregarded, but accounted for by someone. At this point, all the modules do is to zero it out, and no additional time is spent. This highlights where the bus timing is simply dropped instead of being paid for. As a follow up, the locations identified in this patch should add this additional time to the packets in one way or another. For now it simply acts as a sanity check and highlights where the delay is simply ignored. Since no time is added, all regressions remain the same.
231 lines
8 KiB
C++
231 lines
8 KiB
C++
/*
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* Copyright (c) 2011-2013 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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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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* Andreas Hansson
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* William Wang
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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 "debug/Bus.hh"
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#include "debug/BusAddrRanges.hh"
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#include "debug/NoncoherentBus.hh"
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#include "mem/noncoherent_bus.hh"
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NoncoherentBus::NoncoherentBus(const NoncoherentBusParams *p)
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: BaseBus(p), reqLayer(*this, ".reqLayer"),
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respLayer(*this, ".respLayer")
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{
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// create the ports based on the size of the master and slave
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// vector ports, and the presence of the default port, the ports
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// are enumerated starting from zero
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for (int i = 0; i < p->port_master_connection_count; ++i) {
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std::string portName = csprintf("%s.master[%d]", name(), i);
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MasterPort* bp = new NoncoherentBusMasterPort(portName, *this, i);
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masterPorts.push_back(bp);
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}
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// see if we have a default slave device connected and if so add
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// our corresponding master port
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if (p->port_default_connection_count) {
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defaultPortID = masterPorts.size();
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std::string portName = name() + ".default";
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MasterPort* bp = new NoncoherentBusMasterPort(portName, *this,
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defaultPortID);
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masterPorts.push_back(bp);
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}
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// create the slave ports, once again starting at zero
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for (int i = 0; i < p->port_slave_connection_count; ++i) {
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std::string portName = csprintf("%s.slave[%d]", name(), i);
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SlavePort* bp = new NoncoherentBusSlavePort(portName, *this, i);
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slavePorts.push_back(bp);
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}
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clearPortCache();
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}
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bool
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NoncoherentBus::recvTimingReq(PacketPtr pkt, PortID slave_port_id)
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{
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// determine the source port based on the id
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SlavePort *src_port = slavePorts[slave_port_id];
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// we should never see express snoops on a non-coherent bus
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assert(!pkt->isExpressSnoop());
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// test if the bus should be considered occupied for the current
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// port
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if (!reqLayer.tryTiming(src_port)) {
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DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x BUSY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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return false;
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}
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DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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// set the source port for routing of the response
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pkt->setSrc(slave_port_id);
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calcPacketTiming(pkt);
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Tick packetFinishTime = pkt->busLastWordDelay + curTick();
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// since it is a normal request, determine the destination
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// based on the address and attempt to send the packet
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bool success = masterPorts[findPort(pkt->getAddr())]->sendTimingReq(pkt);
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if (!success) {
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// inhibited packets should never be forced to retry
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assert(!pkt->memInhibitAsserted());
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DPRINTF(NoncoherentBus, "recvTimingReq: src %s %s 0x%x RETRY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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// undo the calculation so we can check for 0 again
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pkt->busFirstWordDelay = pkt->busLastWordDelay = 0;
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// occupy until the header is sent
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reqLayer.failedTiming(src_port, clockEdge(Cycles(headerCycles)));
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return false;
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}
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reqLayer.succeededTiming(packetFinishTime);
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return true;
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}
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bool
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NoncoherentBus::recvTimingResp(PacketPtr pkt, PortID master_port_id)
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{
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// determine the source port based on the id
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MasterPort *src_port = masterPorts[master_port_id];
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// test if the bus should be considered occupied for the current
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// port
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if (!respLayer.tryTiming(src_port)) {
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DPRINTF(NoncoherentBus, "recvTimingResp: src %s %s 0x%x BUSY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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return false;
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}
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DPRINTF(NoncoherentBus, "recvTimingResp: src %s %s 0x%x\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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calcPacketTiming(pkt);
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Tick packetFinishTime = pkt->busLastWordDelay + curTick();
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// send the packet to the destination through one of our slave
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// ports, as determined by the destination field
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bool success M5_VAR_USED = slavePorts[pkt->getDest()]->sendTimingResp(pkt);
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// currently it is illegal to block responses... can lead to
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// deadlock
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assert(success);
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respLayer.succeededTiming(packetFinishTime);
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return true;
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}
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void
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NoncoherentBus::recvRetry()
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{
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// responses never block on forwarding them, so the retry will
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// always be coming from a port to which we tried to forward a
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// request
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reqLayer.recvRetry();
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}
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Tick
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NoncoherentBus::recvAtomic(PacketPtr pkt, PortID slave_port_id)
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{
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DPRINTF(NoncoherentBus, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
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slavePorts[slave_port_id]->name(), pkt->getAddr(),
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pkt->cmdString());
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// determine the destination port
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PortID dest_id = findPort(pkt->getAddr());
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// forward the request to the appropriate destination
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Tick response_latency = masterPorts[dest_id]->sendAtomic(pkt);
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// @todo: Not setting first-word time
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pkt->busLastWordDelay = response_latency;
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return response_latency;
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}
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void
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NoncoherentBus::recvFunctional(PacketPtr pkt, PortID slave_port_id)
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{
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if (!pkt->isPrint()) {
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// don't do DPRINTFs on PrintReq as it clutters up the output
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DPRINTF(NoncoherentBus,
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"recvFunctional: packet src %s addr 0x%x cmd %s\n",
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slavePorts[slave_port_id]->name(), pkt->getAddr(),
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pkt->cmdString());
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}
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// determine the destination port
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PortID dest_id = findPort(pkt->getAddr());
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// forward the request to the appropriate destination
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masterPorts[dest_id]->sendFunctional(pkt);
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}
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unsigned int
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NoncoherentBus::drain(DrainManager *dm)
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{
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// sum up the individual layers
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return reqLayer.drain(dm) + respLayer.drain(dm);
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}
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NoncoherentBus*
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NoncoherentBusParams::create()
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{
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return new NoncoherentBus(this);
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}
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