coherent_xbar.cc revision 11544
12497SN/A/* 210719SMarco.Balboni@ARM.com * Copyright (c) 2011-2015 ARM Limited 38711SN/A * All rights reserved 48711SN/A * 58711SN/A * The license below extends only to copyright in the software and shall 68711SN/A * not be construed as granting a license to any other intellectual 78711SN/A * property including but not limited to intellectual property relating 88711SN/A * to a hardware implementation of the functionality of the software 98711SN/A * licensed hereunder. You may use the software subject to the license 108711SN/A * terms below provided that you ensure that this notice is replicated 118711SN/A * unmodified and in its entirety in all distributions of the software, 128711SN/A * modified or unmodified, in source code or in binary form. 138711SN/A * 142497SN/A * Copyright (c) 2006 The Regents of The University of Michigan 152497SN/A * All rights reserved. 162497SN/A * 172497SN/A * Redistribution and use in source and binary forms, with or without 182497SN/A * modification, are permitted provided that the following conditions are 192497SN/A * met: redistributions of source code must retain the above copyright 202497SN/A * notice, this list of conditions and the following disclaimer; 212497SN/A * redistributions in binary form must reproduce the above copyright 222497SN/A * notice, this list of conditions and the following disclaimer in the 232497SN/A * documentation and/or other materials provided with the distribution; 242497SN/A * neither the name of the copyright holders nor the names of its 252497SN/A * contributors may be used to endorse or promote products derived from 262497SN/A * this software without specific prior written permission. 272497SN/A * 282497SN/A * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 292497SN/A * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 302497SN/A * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 312497SN/A * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 322497SN/A * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 332497SN/A * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 342497SN/A * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 352497SN/A * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 362497SN/A * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 372497SN/A * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 382497SN/A * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 392665SN/A * 402665SN/A * Authors: Ali Saidi 418715SN/A * Andreas Hansson 428922SN/A * William Wang 432497SN/A */ 442497SN/A 452497SN/A/** 462982SN/A * @file 4710405Sandreas.hansson@arm.com * Definition of a crossbar object. 482497SN/A */ 492497SN/A 502846SN/A#include "base/misc.hh" 512548SN/A#include "base/trace.hh" 5210405Sandreas.hansson@arm.com#include "debug/AddrRanges.hh" 5310405Sandreas.hansson@arm.com#include "debug/CoherentXBar.hh" 5410405Sandreas.hansson@arm.com#include "mem/coherent_xbar.hh" 559524SN/A#include "sim/system.hh" 562497SN/A 5710405Sandreas.hansson@arm.comCoherentXBar::CoherentXBar(const CoherentXBarParams *p) 5810719SMarco.Balboni@ARM.com : BaseXBar(p), system(p->system), snoopFilter(p->snoop_filter), 5911334Sandreas.hansson@arm.com snoopResponseLatency(p->snoop_response_latency), 6011334Sandreas.hansson@arm.com pointOfCoherency(p->point_of_coherency) 617523SN/A{ 628851SN/A // create the ports based on the size of the master and slave 638948SN/A // vector ports, and the presence of the default port, the ports 648948SN/A // are enumerated starting from zero 658851SN/A for (int i = 0; i < p->port_master_connection_count; ++i) { 669095SN/A std::string portName = csprintf("%s.master[%d]", name(), i); 6710405Sandreas.hansson@arm.com MasterPort* bp = new CoherentXBarMasterPort(portName, *this, i); 688922SN/A masterPorts.push_back(bp); 699715SN/A reqLayers.push_back(new ReqLayer(*bp, *this, 709715SN/A csprintf(".reqLayer%d", i))); 7110713Sandreas.hansson@arm.com snoopLayers.push_back(new SnoopRespLayer(*bp, *this, 7210713Sandreas.hansson@arm.com csprintf(".snoopLayer%d", i))); 738851SN/A } 748851SN/A 758948SN/A // see if we have a default slave device connected and if so add 768948SN/A // our corresponding master port 778915SN/A if (p->port_default_connection_count) { 789031SN/A defaultPortID = masterPorts.size(); 799095SN/A std::string portName = name() + ".default"; 8010405Sandreas.hansson@arm.com MasterPort* bp = new CoherentXBarMasterPort(portName, *this, 819036SN/A defaultPortID); 828922SN/A masterPorts.push_back(bp); 839715SN/A reqLayers.push_back(new ReqLayer(*bp, *this, csprintf(".reqLayer%d", 849715SN/A defaultPortID))); 8510713Sandreas.hansson@arm.com snoopLayers.push_back(new SnoopRespLayer(*bp, *this, 8610713Sandreas.hansson@arm.com csprintf(".snoopLayer%d", 8710713Sandreas.hansson@arm.com defaultPortID))); 888915SN/A } 898915SN/A 908948SN/A // create the slave ports, once again starting at zero 918851SN/A for (int i = 0; i < p->port_slave_connection_count; ++i) { 929095SN/A std::string portName = csprintf("%s.slave[%d]", name(), i); 9310888Sandreas.hansson@arm.com QueuedSlavePort* bp = new CoherentXBarSlavePort(portName, *this, i); 948922SN/A slavePorts.push_back(bp); 959715SN/A respLayers.push_back(new RespLayer(*bp, *this, 969715SN/A csprintf(".respLayer%d", i))); 979716SN/A snoopRespPorts.push_back(new SnoopRespPort(*bp, *this)); 988851SN/A } 998851SN/A 1007523SN/A clearPortCache(); 1017523SN/A} 1027523SN/A 10310405Sandreas.hansson@arm.comCoherentXBar::~CoherentXBar() 1049715SN/A{ 10510405Sandreas.hansson@arm.com for (auto l: reqLayers) 10610405Sandreas.hansson@arm.com delete l; 10710405Sandreas.hansson@arm.com for (auto l: respLayers) 10810405Sandreas.hansson@arm.com delete l; 10910405Sandreas.hansson@arm.com for (auto l: snoopLayers) 11010405Sandreas.hansson@arm.com delete l; 11110405Sandreas.hansson@arm.com for (auto p: snoopRespPorts) 11210405Sandreas.hansson@arm.com delete p; 1139715SN/A} 1149715SN/A 1152568SN/Avoid 11610405Sandreas.hansson@arm.comCoherentXBar::init() 1172568SN/A{ 11810405Sandreas.hansson@arm.com BaseXBar::init(); 1199278SN/A 1208948SN/A // iterate over our slave ports and determine which of our 1218948SN/A // neighbouring master ports are snooping and add them as snoopers 12210405Sandreas.hansson@arm.com for (const auto& p: slavePorts) { 1239088SN/A // check if the connected master port is snooping 12410405Sandreas.hansson@arm.com if (p->isSnooping()) { 12510405Sandreas.hansson@arm.com DPRINTF(AddrRanges, "Adding snooping master %s\n", 12610405Sandreas.hansson@arm.com p->getMasterPort().name()); 12710405Sandreas.hansson@arm.com snoopPorts.push_back(p); 1288711SN/A } 1298711SN/A } 1302568SN/A 1319036SN/A if (snoopPorts.empty()) 13210405Sandreas.hansson@arm.com warn("CoherentXBar %s has no snooping ports attached!\n", name()); 13311133Sandreas.hansson@arm.com 13411133Sandreas.hansson@arm.com // inform the snoop filter about the slave ports so it can create 13511133Sandreas.hansson@arm.com // its own internal representation 13611133Sandreas.hansson@arm.com if (snoopFilter) 13711133Sandreas.hansson@arm.com snoopFilter->setSlavePorts(slavePorts); 1383244SN/A} 1393244SN/A 1408948SN/Abool 14110405Sandreas.hansson@arm.comCoherentXBar::recvTimingReq(PacketPtr pkt, PortID slave_port_id) 1423244SN/A{ 1438975SN/A // determine the source port based on the id 1449032SN/A SlavePort *src_port = slavePorts[slave_port_id]; 1453244SN/A 1469091SN/A // remember if the packet is an express snoop 1479091SN/A bool is_express_snoop = pkt->isExpressSnoop(); 14811284Sandreas.hansson@arm.com bool cache_responding = pkt->cacheResponding(); 14910656Sandreas.hansson@arm.com // for normal requests, going downstream, the express snoop flag 15011284Sandreas.hansson@arm.com // and the cache responding flag should always be the same 15111284Sandreas.hansson@arm.com assert(is_express_snoop == cache_responding); 1529091SN/A 1539612SN/A // determine the destination based on the address 1549712SN/A PortID master_port_id = findPort(pkt->getAddr()); 1559612SN/A 15610405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the current 1579033SN/A // port, and exclude express snoops from the check 1589715SN/A if (!is_express_snoop && !reqLayers[master_port_id]->tryTiming(src_port)) { 15910405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingReq: src %s %s 0x%x BUSY\n", 1608949SN/A src_port->name(), pkt->cmdString(), pkt->getAddr()); 1613244SN/A return false; 1623244SN/A } 1633244SN/A 16410405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingReq: src %s %s expr %d 0x%x\n", 1659091SN/A src_port->name(), pkt->cmdString(), is_express_snoop, 1669091SN/A pkt->getAddr()); 1675197SN/A 1689712SN/A // store size and command as they might be modified when 1699712SN/A // forwarding the packet 1709712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 1719712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 1729712SN/A 17310719SMarco.Balboni@ARM.com // store the old header delay so we can restore it if needed 17410719SMarco.Balboni@ARM.com Tick old_header_delay = pkt->headerDelay; 17510719SMarco.Balboni@ARM.com 17610719SMarco.Balboni@ARM.com // a request sees the frontend and forward latency 17710719SMarco.Balboni@ARM.com Tick xbar_delay = (frontendLatency + forwardLatency) * clockPeriod(); 17810719SMarco.Balboni@ARM.com 17910719SMarco.Balboni@ARM.com // set the packet header and payload delay 18010719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 18110719SMarco.Balboni@ARM.com 18210719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 18310719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 1844912SN/A 18510821Sandreas.hansson@arm.com if (!system->bypassCaches()) { 18611127Sandreas.hansson@arm.com assert(pkt->snoopDelay == 0); 18711127Sandreas.hansson@arm.com 1888979SN/A // the packet is a memory-mapped request and should be 1898979SN/A // broadcasted to our snoopers but the source 19010402SN/A if (snoopFilter) { 19110402SN/A // check with the snoop filter where to forward this packet 19210402SN/A auto sf_res = snoopFilter->lookupRequest(pkt, *src_port); 19311126Sandreas.hansson@arm.com // the time required by a packet to be delivered through 19411126Sandreas.hansson@arm.com // the xbar has to be charged also with to lookup latency 19511126Sandreas.hansson@arm.com // of the snoop filter 19610719SMarco.Balboni@ARM.com pkt->headerDelay += sf_res.second * clockPeriod(); 19710405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingReq: src %s %s 0x%x"\ 19810402SN/A " SF size: %i lat: %i\n", src_port->name(), 19910402SN/A pkt->cmdString(), pkt->getAddr(), sf_res.first.size(), 20010402SN/A sf_res.second); 20111196Sali.jafri@arm.com 20211199Sandreas.hansson@arm.com if (pkt->isEviction()) { 20311196Sali.jafri@arm.com // for block-evicting packets, i.e. writebacks and 20411196Sali.jafri@arm.com // clean evictions, there is no need to snoop up, as 20511196Sali.jafri@arm.com // all we do is determine if the block is cached or 20611196Sali.jafri@arm.com // not, instead just set it here based on the snoop 20711196Sali.jafri@arm.com // filter result 20811196Sali.jafri@arm.com if (!sf_res.first.empty()) 20911196Sali.jafri@arm.com pkt->setBlockCached(); 21011196Sali.jafri@arm.com } else { 21111196Sali.jafri@arm.com forwardTiming(pkt, slave_port_id, sf_res.first); 21211196Sali.jafri@arm.com } 21310402SN/A } else { 21410402SN/A forwardTiming(pkt, slave_port_id); 21510402SN/A } 21611127Sandreas.hansson@arm.com 21711127Sandreas.hansson@arm.com // add the snoop delay to our header delay, and then reset it 21811127Sandreas.hansson@arm.com pkt->headerDelay += pkt->snoopDelay; 21911127Sandreas.hansson@arm.com pkt->snoopDelay = 0; 2208979SN/A } 2218948SN/A 22211334Sandreas.hansson@arm.com // set up a sensible starting point 22311334Sandreas.hansson@arm.com bool success = true; 22410883Sali.jafri@arm.com 22511284Sandreas.hansson@arm.com // remember if the packet will generate a snoop response by 22611284Sandreas.hansson@arm.com // checking if a cache set the cacheResponding flag during the 22711284Sandreas.hansson@arm.com // snooping above 22811284Sandreas.hansson@arm.com const bool expect_snoop_resp = !cache_responding && pkt->cacheResponding(); 22911334Sandreas.hansson@arm.com bool expect_response = pkt->needsResponse() && !pkt->cacheResponding(); 2308915SN/A 23111334Sandreas.hansson@arm.com const bool sink_packet = sinkPacket(pkt); 23211334Sandreas.hansson@arm.com 23311334Sandreas.hansson@arm.com // in certain cases the crossbar is responsible for responding 23411334Sandreas.hansson@arm.com bool respond_directly = false; 23511544Snikos.nikoleris@arm.com // store the original address as an address mapper could possibly 23611544Snikos.nikoleris@arm.com // modify the address upon a sendTimingRequest 23711544Snikos.nikoleris@arm.com const Addr addr(pkt->getAddr()); 23811334Sandreas.hansson@arm.com if (sink_packet) { 23911334Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "Not forwarding %s to %#llx\n", 24011334Sandreas.hansson@arm.com pkt->cmdString(), pkt->getAddr()); 24111334Sandreas.hansson@arm.com } else { 24211334Sandreas.hansson@arm.com // determine if we are forwarding the packet, or responding to 24311334Sandreas.hansson@arm.com // it 24411334Sandreas.hansson@arm.com if (!pointOfCoherency || pkt->isRead() || pkt->isWrite()) { 24511334Sandreas.hansson@arm.com // if we are passing on, rather than sinking, a packet to 24611334Sandreas.hansson@arm.com // which an upstream cache has committed to responding, 24711334Sandreas.hansson@arm.com // the line was needs writable, and the responding only 24811334Sandreas.hansson@arm.com // had an Owned copy, so we need to immidiately let the 24911334Sandreas.hansson@arm.com // downstream caches know, bypass any flow control 25011334Sandreas.hansson@arm.com if (pkt->cacheResponding()) { 25111334Sandreas.hansson@arm.com pkt->setExpressSnoop(); 25211334Sandreas.hansson@arm.com } 25311334Sandreas.hansson@arm.com 25411334Sandreas.hansson@arm.com // since it is a normal request, attempt to send the packet 25511334Sandreas.hansson@arm.com success = masterPorts[master_port_id]->sendTimingReq(pkt); 25611334Sandreas.hansson@arm.com } else { 25711334Sandreas.hansson@arm.com // no need to forward, turn this packet around and respond 25811334Sandreas.hansson@arm.com // directly 25911334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 26011334Sandreas.hansson@arm.com 26111334Sandreas.hansson@arm.com respond_directly = true; 26211334Sandreas.hansson@arm.com assert(!expect_snoop_resp); 26311334Sandreas.hansson@arm.com expect_response = false; 26411334Sandreas.hansson@arm.com } 26511334Sandreas.hansson@arm.com } 2668948SN/A 26710821Sandreas.hansson@arm.com if (snoopFilter && !system->bypassCaches()) { 26810402SN/A // Let the snoop filter know about the success of the send operation 26911544Snikos.nikoleris@arm.com snoopFilter->finishRequest(!success, addr); 27010402SN/A } 27110402SN/A 27210656Sandreas.hansson@arm.com // check if we were successful in sending the packet onwards 27310656Sandreas.hansson@arm.com if (!success) { 27411284Sandreas.hansson@arm.com // express snoops should never be forced to retry 27510656Sandreas.hansson@arm.com assert(!is_express_snoop); 27610656Sandreas.hansson@arm.com 27710719SMarco.Balboni@ARM.com // restore the header delay 27810719SMarco.Balboni@ARM.com pkt->headerDelay = old_header_delay; 27910656Sandreas.hansson@arm.com 28010656Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingReq: src %s %s 0x%x RETRY\n", 28110656Sandreas.hansson@arm.com src_port->name(), pkt->cmdString(), pkt->getAddr()); 28210656Sandreas.hansson@arm.com 28310656Sandreas.hansson@arm.com // update the layer state and schedule an idle event 28410656Sandreas.hansson@arm.com reqLayers[master_port_id]->failedTiming(src_port, 28510719SMarco.Balboni@ARM.com clockEdge(Cycles(1))); 2869091SN/A } else { 28710656Sandreas.hansson@arm.com // express snoops currently bypass the crossbar state entirely 28810656Sandreas.hansson@arm.com if (!is_express_snoop) { 28910656Sandreas.hansson@arm.com // if this particular request will generate a snoop 29010656Sandreas.hansson@arm.com // response 29110656Sandreas.hansson@arm.com if (expect_snoop_resp) { 29210656Sandreas.hansson@arm.com // we should never have an exsiting request outstanding 29310656Sandreas.hansson@arm.com assert(outstandingSnoop.find(pkt->req) == 29410656Sandreas.hansson@arm.com outstandingSnoop.end()); 29510656Sandreas.hansson@arm.com outstandingSnoop.insert(pkt->req); 2968948SN/A 29710656Sandreas.hansson@arm.com // basic sanity check on the outstanding snoops 29810656Sandreas.hansson@arm.com panic_if(outstandingSnoop.size() > 512, 29910656Sandreas.hansson@arm.com "Outstanding snoop requests exceeded 512\n"); 30010656Sandreas.hansson@arm.com } 3018948SN/A 30210656Sandreas.hansson@arm.com // remember where to route the normal response to 30310656Sandreas.hansson@arm.com if (expect_response || expect_snoop_resp) { 30410656Sandreas.hansson@arm.com assert(routeTo.find(pkt->req) == routeTo.end()); 30510656Sandreas.hansson@arm.com routeTo[pkt->req] = slave_port_id; 3069549SN/A 30710656Sandreas.hansson@arm.com panic_if(routeTo.size() > 512, 30810656Sandreas.hansson@arm.com "Routing table exceeds 512 packets\n"); 30910656Sandreas.hansson@arm.com } 3108948SN/A 31110405Sandreas.hansson@arm.com // update the layer state and schedule an idle event 3129715SN/A reqLayers[master_port_id]->succeededTiming(packetFinishTime); 3139091SN/A } 3148975SN/A 31510656Sandreas.hansson@arm.com // stats updates only consider packets that were successfully sent 3169712SN/A pktCount[slave_port_id][master_port_id]++; 31710405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 3189712SN/A transDist[pkt_cmd]++; 31910656Sandreas.hansson@arm.com 32010656Sandreas.hansson@arm.com if (is_express_snoop) 32110656Sandreas.hansson@arm.com snoops++; 3229712SN/A } 3239712SN/A 32411334Sandreas.hansson@arm.com if (sink_packet) 32511334Sandreas.hansson@arm.com // queue the packet for deletion 32611334Sandreas.hansson@arm.com pendingDelete.reset(pkt); 32711334Sandreas.hansson@arm.com 32811334Sandreas.hansson@arm.com if (respond_directly) { 32911334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 33011334Sandreas.hansson@arm.com assert(success); 33111334Sandreas.hansson@arm.com 33211334Sandreas.hansson@arm.com pkt->makeResponse(); 33311334Sandreas.hansson@arm.com 33411334Sandreas.hansson@arm.com if (snoopFilter && !system->bypassCaches()) { 33511334Sandreas.hansson@arm.com // let the snoop filter inspect the response and update its state 33611334Sandreas.hansson@arm.com snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 33711334Sandreas.hansson@arm.com } 33811334Sandreas.hansson@arm.com 33911334Sandreas.hansson@arm.com Tick response_time = clockEdge() + pkt->headerDelay; 34011334Sandreas.hansson@arm.com pkt->headerDelay = 0; 34111334Sandreas.hansson@arm.com 34211334Sandreas.hansson@arm.com slavePorts[slave_port_id]->schedTimingResp(pkt, response_time); 34311334Sandreas.hansson@arm.com } 34411334Sandreas.hansson@arm.com 3459091SN/A return success; 3468975SN/A} 3478975SN/A 3488975SN/Abool 34910405Sandreas.hansson@arm.comCoherentXBar::recvTimingResp(PacketPtr pkt, PortID master_port_id) 3508975SN/A{ 3518975SN/A // determine the source port based on the id 3529032SN/A MasterPort *src_port = masterPorts[master_port_id]; 3538975SN/A 35410656Sandreas.hansson@arm.com // determine the destination 35510656Sandreas.hansson@arm.com const auto route_lookup = routeTo.find(pkt->req); 35610656Sandreas.hansson@arm.com assert(route_lookup != routeTo.end()); 35710656Sandreas.hansson@arm.com const PortID slave_port_id = route_lookup->second; 35810572Sandreas.hansson@arm.com assert(slave_port_id != InvalidPortID); 35910572Sandreas.hansson@arm.com assert(slave_port_id < respLayers.size()); 3609713SN/A 36110405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the 36210405Sandreas.hansson@arm.com // current port 3639715SN/A if (!respLayers[slave_port_id]->tryTiming(src_port)) { 36410405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingResp: src %s %s 0x%x BUSY\n", 3658975SN/A src_port->name(), pkt->cmdString(), pkt->getAddr()); 3668975SN/A return false; 3678975SN/A } 3688975SN/A 36910405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingResp: src %s %s 0x%x\n", 3708975SN/A src_port->name(), pkt->cmdString(), pkt->getAddr()); 3718975SN/A 3729712SN/A // store size and command as they might be modified when 3739712SN/A // forwarding the packet 3749712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 3759712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 3769712SN/A 37710719SMarco.Balboni@ARM.com // a response sees the response latency 37810719SMarco.Balboni@ARM.com Tick xbar_delay = responseLatency * clockPeriod(); 37910719SMarco.Balboni@ARM.com 38010719SMarco.Balboni@ARM.com // set the packet header and payload delay 38110719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 38210719SMarco.Balboni@ARM.com 38310719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 38410719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 3858975SN/A 38610821Sandreas.hansson@arm.com if (snoopFilter && !system->bypassCaches()) { 38710402SN/A // let the snoop filter inspect the response and update its state 38810402SN/A snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 38910402SN/A } 39010402SN/A 39110888Sandreas.hansson@arm.com // send the packet through the destination slave port and pay for 39210888Sandreas.hansson@arm.com // any outstanding header delay 39310888Sandreas.hansson@arm.com Tick latency = pkt->headerDelay; 39410888Sandreas.hansson@arm.com pkt->headerDelay = 0; 39510888Sandreas.hansson@arm.com slavePorts[slave_port_id]->schedTimingResp(pkt, curTick() + latency); 3968975SN/A 39710656Sandreas.hansson@arm.com // remove the request from the routing table 39810656Sandreas.hansson@arm.com routeTo.erase(route_lookup); 39910656Sandreas.hansson@arm.com 4009715SN/A respLayers[slave_port_id]->succeededTiming(packetFinishTime); 4018975SN/A 4029712SN/A // stats updates 4039712SN/A pktCount[slave_port_id][master_port_id]++; 40410405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 4059712SN/A transDist[pkt_cmd]++; 4069712SN/A 4078975SN/A return true; 4088975SN/A} 4098975SN/A 4108975SN/Avoid 41110405Sandreas.hansson@arm.comCoherentXBar::recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id) 4128975SN/A{ 41310405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopReq: src %s %s 0x%x\n", 4149032SN/A masterPorts[master_port_id]->name(), pkt->cmdString(), 4158975SN/A pkt->getAddr()); 4168975SN/A 4179712SN/A // update stats here as we know the forwarding will succeed 4189712SN/A transDist[pkt->cmdToIndex()]++; 41910405Sandreas.hansson@arm.com snoops++; 4209712SN/A 4218975SN/A // we should only see express snoops from caches 4228975SN/A assert(pkt->isExpressSnoop()); 4238975SN/A 42411127Sandreas.hansson@arm.com // set the packet header and payload delay, for now use forward latency 42511127Sandreas.hansson@arm.com // @todo Assess the choice of latency further 42611127Sandreas.hansson@arm.com calcPacketTiming(pkt, forwardLatency * clockPeriod()); 42711127Sandreas.hansson@arm.com 42811284Sandreas.hansson@arm.com // remember if a cache has already committed to responding so we 42911284Sandreas.hansson@arm.com // can see if it changes during the snooping 43011284Sandreas.hansson@arm.com const bool cache_responding = pkt->cacheResponding(); 4319032SN/A 43211127Sandreas.hansson@arm.com assert(pkt->snoopDelay == 0); 43311127Sandreas.hansson@arm.com 43410402SN/A if (snoopFilter) { 43510402SN/A // let the Snoop Filter work its magic and guide probing 43610402SN/A auto sf_res = snoopFilter->lookupSnoop(pkt); 43711126Sandreas.hansson@arm.com // the time required by a packet to be delivered through 43811126Sandreas.hansson@arm.com // the xbar has to be charged also with to lookup latency 43911126Sandreas.hansson@arm.com // of the snoop filter 44011126Sandreas.hansson@arm.com pkt->headerDelay += sf_res.second * clockPeriod(); 44110405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopReq: src %s %s 0x%x"\ 44210402SN/A " SF size: %i lat: %i\n", masterPorts[master_port_id]->name(), 44310402SN/A pkt->cmdString(), pkt->getAddr(), sf_res.first.size(), 44410402SN/A sf_res.second); 44510402SN/A 44610402SN/A // forward to all snoopers 44710402SN/A forwardTiming(pkt, InvalidPortID, sf_res.first); 44810402SN/A } else { 44910402SN/A forwardTiming(pkt, InvalidPortID); 45010402SN/A } 4518975SN/A 45211127Sandreas.hansson@arm.com // add the snoop delay to our header delay, and then reset it 45311127Sandreas.hansson@arm.com pkt->headerDelay += pkt->snoopDelay; 45411127Sandreas.hansson@arm.com pkt->snoopDelay = 0; 45511127Sandreas.hansson@arm.com 45610656Sandreas.hansson@arm.com // if we can expect a response, remember how to route it 45711284Sandreas.hansson@arm.com if (!cache_responding && pkt->cacheResponding()) { 45810656Sandreas.hansson@arm.com assert(routeTo.find(pkt->req) == routeTo.end()); 45910656Sandreas.hansson@arm.com routeTo[pkt->req] = master_port_id; 46010656Sandreas.hansson@arm.com } 46110656Sandreas.hansson@arm.com 4628975SN/A // a snoop request came from a connected slave device (one of 4638975SN/A // our master ports), and if it is not coming from the slave 4648975SN/A // device responsible for the address range something is 4658975SN/A // wrong, hence there is nothing further to do as the packet 4668975SN/A // would be going back to where it came from 4679032SN/A assert(master_port_id == findPort(pkt->getAddr())); 4688975SN/A} 4698975SN/A 4708975SN/Abool 47110405Sandreas.hansson@arm.comCoherentXBar::recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id) 4728975SN/A{ 4738975SN/A // determine the source port based on the id 4749032SN/A SlavePort* src_port = slavePorts[slave_port_id]; 4758975SN/A 47610656Sandreas.hansson@arm.com // get the destination 47710656Sandreas.hansson@arm.com const auto route_lookup = routeTo.find(pkt->req); 47810656Sandreas.hansson@arm.com assert(route_lookup != routeTo.end()); 47910656Sandreas.hansson@arm.com const PortID dest_port_id = route_lookup->second; 48010572Sandreas.hansson@arm.com assert(dest_port_id != InvalidPortID); 4819714SN/A 4829714SN/A // determine if the response is from a snoop request we 4839714SN/A // created as the result of a normal request (in which case it 48410656Sandreas.hansson@arm.com // should be in the outstandingSnoop), or if we merely forwarded 4859714SN/A // someone else's snoop request 48610656Sandreas.hansson@arm.com const bool forwardAsSnoop = outstandingSnoop.find(pkt->req) == 48710656Sandreas.hansson@arm.com outstandingSnoop.end(); 4889714SN/A 48910405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the 49010405Sandreas.hansson@arm.com // current port, note that the check is bypassed if the response 49110405Sandreas.hansson@arm.com // is being passed on as a normal response since this is occupying 49210405Sandreas.hansson@arm.com // the response layer rather than the snoop response layer 4939715SN/A if (forwardAsSnoop) { 49410572Sandreas.hansson@arm.com assert(dest_port_id < snoopLayers.size()); 4959715SN/A if (!snoopLayers[dest_port_id]->tryTiming(src_port)) { 49610405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopResp: src %s %s 0x%x BUSY\n", 4979715SN/A src_port->name(), pkt->cmdString(), pkt->getAddr()); 4989715SN/A return false; 4999715SN/A } 5009716SN/A } else { 5019716SN/A // get the master port that mirrors this slave port internally 5029716SN/A MasterPort* snoop_port = snoopRespPorts[slave_port_id]; 50310572Sandreas.hansson@arm.com assert(dest_port_id < respLayers.size()); 5049716SN/A if (!respLayers[dest_port_id]->tryTiming(snoop_port)) { 50510405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopResp: src %s %s 0x%x BUSY\n", 5069716SN/A snoop_port->name(), pkt->cmdString(), pkt->getAddr()); 5079716SN/A return false; 5089716SN/A } 5098975SN/A } 5108975SN/A 51110405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopResp: src %s %s 0x%x\n", 5128975SN/A src_port->name(), pkt->cmdString(), pkt->getAddr()); 5138975SN/A 5149712SN/A // store size and command as they might be modified when 5159712SN/A // forwarding the packet 5169712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 5179712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 5189712SN/A 5198975SN/A // responses are never express snoops 5208975SN/A assert(!pkt->isExpressSnoop()); 5218975SN/A 52210719SMarco.Balboni@ARM.com // a snoop response sees the snoop response latency, and if it is 52310719SMarco.Balboni@ARM.com // forwarded as a normal response, the response latency 52410719SMarco.Balboni@ARM.com Tick xbar_delay = 52510719SMarco.Balboni@ARM.com (forwardAsSnoop ? snoopResponseLatency : responseLatency) * 52610719SMarco.Balboni@ARM.com clockPeriod(); 52710719SMarco.Balboni@ARM.com 52810719SMarco.Balboni@ARM.com // set the packet header and payload delay 52910719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 53010719SMarco.Balboni@ARM.com 53110719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 53210719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 5338975SN/A 5349714SN/A // forward it either as a snoop response or a normal response 5359714SN/A if (forwardAsSnoop) { 5369714SN/A // this is a snoop response to a snoop request we forwarded, 5379714SN/A // e.g. coming from the L1 and going to the L2, and it should 5389714SN/A // be forwarded as a snoop response 53910402SN/A 54010402SN/A if (snoopFilter) { 54110402SN/A // update the probe filter so that it can properly track the line 54210402SN/A snoopFilter->updateSnoopForward(pkt, *slavePorts[slave_port_id], 54310402SN/A *masterPorts[dest_port_id]); 54410402SN/A } 54510402SN/A 5469712SN/A bool success M5_VAR_USED = 5479712SN/A masterPorts[dest_port_id]->sendTimingSnoopResp(pkt); 5489712SN/A pktCount[slave_port_id][dest_port_id]++; 54910405Sandreas.hansson@arm.com pktSize[slave_port_id][dest_port_id] += pkt_size; 5508975SN/A assert(success); 5519714SN/A 5529715SN/A snoopLayers[dest_port_id]->succeededTiming(packetFinishTime); 5533244SN/A } else { 5548975SN/A // we got a snoop response on one of our slave ports, 55510405Sandreas.hansson@arm.com // i.e. from a coherent master connected to the crossbar, and 55610405Sandreas.hansson@arm.com // since we created the snoop request as part of recvTiming, 55710405Sandreas.hansson@arm.com // this should now be a normal response again 55810656Sandreas.hansson@arm.com outstandingSnoop.erase(pkt->req); 5598948SN/A 56010656Sandreas.hansson@arm.com // this is a snoop response from a coherent master, hence it 56110656Sandreas.hansson@arm.com // should never go back to where the snoop response came from, 56210656Sandreas.hansson@arm.com // but instead to where the original request came from 5639712SN/A assert(slave_port_id != dest_port_id); 5648948SN/A 56510402SN/A if (snoopFilter) { 56610402SN/A // update the probe filter so that it can properly track the line 56710402SN/A snoopFilter->updateSnoopResponse(pkt, *slavePorts[slave_port_id], 56810402SN/A *slavePorts[dest_port_id]); 56910402SN/A } 57010402SN/A 57110405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvTimingSnoopResp: src %s %s 0x%x"\ 57210402SN/A " FWD RESP\n", src_port->name(), pkt->cmdString(), 57310402SN/A pkt->getAddr()); 57410402SN/A 5759714SN/A // as a normal response, it should go back to a master through 57610888Sandreas.hansson@arm.com // one of our slave ports, we also pay for any outstanding 57710888Sandreas.hansson@arm.com // header latency 57810888Sandreas.hansson@arm.com Tick latency = pkt->headerDelay; 57910888Sandreas.hansson@arm.com pkt->headerDelay = 0; 58010888Sandreas.hansson@arm.com slavePorts[dest_port_id]->schedTimingResp(pkt, curTick() + latency); 5819716SN/A 5829716SN/A respLayers[dest_port_id]->succeededTiming(packetFinishTime); 5833244SN/A } 5843244SN/A 58510656Sandreas.hansson@arm.com // remove the request from the routing table 58610656Sandreas.hansson@arm.com routeTo.erase(route_lookup); 58710656Sandreas.hansson@arm.com 5889712SN/A // stats updates 5899712SN/A transDist[pkt_cmd]++; 59010405Sandreas.hansson@arm.com snoops++; 5919712SN/A 5928948SN/A return true; 5938948SN/A} 5948948SN/A 5953210SN/A 5968948SN/Avoid 59710405Sandreas.hansson@arm.comCoherentXBar::forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id, 59810888Sandreas.hansson@arm.com const std::vector<QueuedSlavePort*>& dests) 5998948SN/A{ 60010405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "%s for %s address %x size %d\n", __func__, 6019663SN/A pkt->cmdString(), pkt->getAddr(), pkt->getSize()); 6029663SN/A 6039524SN/A // snoops should only happen if the system isn't bypassing caches 6049524SN/A assert(!system->bypassCaches()); 6059524SN/A 60610401SN/A unsigned fanout = 0; 60710401SN/A 60810405Sandreas.hansson@arm.com for (const auto& p: dests) { 6098948SN/A // we could have gotten this request from a snooping master 6108948SN/A // (corresponding to our own slave port that is also in 6118948SN/A // snoopPorts) and should not send it back to where it came 6128948SN/A // from 6139031SN/A if (exclude_slave_port_id == InvalidPortID || 6148948SN/A p->getId() != exclude_slave_port_id) { 6158948SN/A // cache is not allowed to refuse snoop 6168975SN/A p->sendTimingSnoopReq(pkt); 61710401SN/A fanout++; 6188948SN/A } 6198948SN/A } 62010401SN/A 62110401SN/A // Stats for fanout of this forward operation 62210401SN/A snoopFanout.sample(fanout); 6232497SN/A} 6242497SN/A 6259092SN/Avoid 62610713Sandreas.hansson@arm.comCoherentXBar::recvReqRetry(PortID master_port_id) 6279092SN/A{ 6289093SN/A // responses and snoop responses never block on forwarding them, 6299093SN/A // so the retry will always be coming from a port to which we 6309093SN/A // tried to forward a request 6319715SN/A reqLayers[master_port_id]->recvRetry(); 6329092SN/A} 6339092SN/A 6349036SN/ATick 63510405Sandreas.hansson@arm.comCoherentXBar::recvAtomic(PacketPtr pkt, PortID slave_port_id) 6362657SN/A{ 63710405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvAtomic: packet src %s addr 0x%x cmd %s\n", 6389032SN/A slavePorts[slave_port_id]->name(), pkt->getAddr(), 6398949SN/A pkt->cmdString()); 6408915SN/A 64110405Sandreas.hansson@arm.com unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 64210405Sandreas.hansson@arm.com unsigned int pkt_cmd = pkt->cmdToIndex(); 6439712SN/A 6448979SN/A MemCmd snoop_response_cmd = MemCmd::InvalidCmd; 6458979SN/A Tick snoop_response_latency = 0; 6468979SN/A 64710821Sandreas.hansson@arm.com if (!system->bypassCaches()) { 6488979SN/A // forward to all snoopers but the source 64910402SN/A std::pair<MemCmd, Tick> snoop_result; 65010402SN/A if (snoopFilter) { 65110402SN/A // check with the snoop filter where to forward this packet 65210402SN/A auto sf_res = 65310402SN/A snoopFilter->lookupRequest(pkt, *slavePorts[slave_port_id]); 65410402SN/A snoop_response_latency += sf_res.second * clockPeriod(); 65510405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "%s: src %s %s 0x%x"\ 65610402SN/A " SF size: %i lat: %i\n", __func__, 65710402SN/A slavePorts[slave_port_id]->name(), pkt->cmdString(), 65810402SN/A pkt->getAddr(), sf_res.first.size(), sf_res.second); 65911130Sali.jafri@arm.com 66011130Sali.jafri@arm.com // let the snoop filter know about the success of the send 66111130Sali.jafri@arm.com // operation, and do it even before sending it onwards to 66211130Sali.jafri@arm.com // avoid situations where atomic upward snoops sneak in 66311130Sali.jafri@arm.com // between and change the filter state 66411544Snikos.nikoleris@arm.com snoopFilter->finishRequest(false, pkt->getAddr()); 66511130Sali.jafri@arm.com 66610402SN/A snoop_result = forwardAtomic(pkt, slave_port_id, InvalidPortID, 66710402SN/A sf_res.first); 66810402SN/A } else { 66910402SN/A snoop_result = forwardAtomic(pkt, slave_port_id); 67010402SN/A } 6718979SN/A snoop_response_cmd = snoop_result.first; 67210402SN/A snoop_response_latency += snoop_result.second; 6738979SN/A } 6748915SN/A 67511334Sandreas.hansson@arm.com // set up a sensible default value 67611334Sandreas.hansson@arm.com Tick response_latency = 0; 67711334Sandreas.hansson@arm.com 67811334Sandreas.hansson@arm.com const bool sink_packet = sinkPacket(pkt); 67911130Sali.jafri@arm.com 6808948SN/A // even if we had a snoop response, we must continue and also 6818948SN/A // perform the actual request at the destination 68210405Sandreas.hansson@arm.com PortID master_port_id = findPort(pkt->getAddr()); 68310405Sandreas.hansson@arm.com 68411334Sandreas.hansson@arm.com if (sink_packet) { 68511334Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "Not forwarding %s to %#llx\n", 68611334Sandreas.hansson@arm.com pkt->cmdString(), pkt->getAddr()); 68711334Sandreas.hansson@arm.com } else { 68811334Sandreas.hansson@arm.com if (!pointOfCoherency || pkt->isRead() || pkt->isWrite()) { 68911334Sandreas.hansson@arm.com // forward the request to the appropriate destination 69011334Sandreas.hansson@arm.com response_latency = masterPorts[master_port_id]->sendAtomic(pkt); 69111334Sandreas.hansson@arm.com } else { 69211334Sandreas.hansson@arm.com // if it does not need a response we sink the packet above 69311334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 69411334Sandreas.hansson@arm.com 69511334Sandreas.hansson@arm.com pkt->makeResponse(); 69611334Sandreas.hansson@arm.com } 69711334Sandreas.hansson@arm.com } 69811334Sandreas.hansson@arm.com 69910405Sandreas.hansson@arm.com // stats updates for the request 70010405Sandreas.hansson@arm.com pktCount[slave_port_id][master_port_id]++; 70110405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 70210405Sandreas.hansson@arm.com transDist[pkt_cmd]++; 7038948SN/A 7048948SN/A 70511130Sali.jafri@arm.com // if lower levels have replied, tell the snoop filter 70611130Sali.jafri@arm.com if (!system->bypassCaches() && snoopFilter && pkt->isResponse()) { 70710402SN/A snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 70810402SN/A } 70910402SN/A 7108948SN/A // if we got a response from a snooper, restore it here 7118948SN/A if (snoop_response_cmd != MemCmd::InvalidCmd) { 7128948SN/A // no one else should have responded 7138948SN/A assert(!pkt->isResponse()); 7148948SN/A pkt->cmd = snoop_response_cmd; 7158948SN/A response_latency = snoop_response_latency; 7168948SN/A } 7178948SN/A 7189712SN/A // add the response data 71910405Sandreas.hansson@arm.com if (pkt->isResponse()) { 72010405Sandreas.hansson@arm.com pkt_size = pkt->hasData() ? pkt->getSize() : 0; 72110405Sandreas.hansson@arm.com pkt_cmd = pkt->cmdToIndex(); 72210405Sandreas.hansson@arm.com 72310405Sandreas.hansson@arm.com // stats updates 72410405Sandreas.hansson@arm.com pktCount[slave_port_id][master_port_id]++; 72510405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 72610405Sandreas.hansson@arm.com transDist[pkt_cmd]++; 72710405Sandreas.hansson@arm.com } 7289712SN/A 72910694SMarco.Balboni@ARM.com // @todo: Not setting header time 73010694SMarco.Balboni@ARM.com pkt->payloadDelay = response_latency; 7318948SN/A return response_latency; 7328948SN/A} 7338948SN/A 7348948SN/ATick 73510405Sandreas.hansson@arm.comCoherentXBar::recvAtomicSnoop(PacketPtr pkt, PortID master_port_id) 7368948SN/A{ 73710405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "recvAtomicSnoop: packet src %s addr 0x%x cmd %s\n", 7389032SN/A masterPorts[master_port_id]->name(), pkt->getAddr(), 7398949SN/A pkt->cmdString()); 7408948SN/A 7419712SN/A // add the request snoop data 74210405Sandreas.hansson@arm.com snoops++; 7439712SN/A 7448948SN/A // forward to all snoopers 74510402SN/A std::pair<MemCmd, Tick> snoop_result; 74610402SN/A Tick snoop_response_latency = 0; 74710402SN/A if (snoopFilter) { 74810402SN/A auto sf_res = snoopFilter->lookupSnoop(pkt); 74910402SN/A snoop_response_latency += sf_res.second * clockPeriod(); 75010405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, "%s: src %s %s 0x%x SF size: %i lat: %i\n", 75110402SN/A __func__, masterPorts[master_port_id]->name(), pkt->cmdString(), 75210402SN/A pkt->getAddr(), sf_res.first.size(), sf_res.second); 75310402SN/A snoop_result = forwardAtomic(pkt, InvalidPortID, master_port_id, 75410402SN/A sf_res.first); 75510402SN/A } else { 75610402SN/A snoop_result = forwardAtomic(pkt, InvalidPortID); 75710402SN/A } 7588948SN/A MemCmd snoop_response_cmd = snoop_result.first; 75910402SN/A snoop_response_latency += snoop_result.second; 7608948SN/A 7618948SN/A if (snoop_response_cmd != MemCmd::InvalidCmd) 7628948SN/A pkt->cmd = snoop_response_cmd; 7638948SN/A 7649712SN/A // add the response snoop data 76510401SN/A if (pkt->isResponse()) { 76610405Sandreas.hansson@arm.com snoops++; 76710401SN/A } 7689712SN/A 76910694SMarco.Balboni@ARM.com // @todo: Not setting header time 77010694SMarco.Balboni@ARM.com pkt->payloadDelay = snoop_response_latency; 7718948SN/A return snoop_response_latency; 7728948SN/A} 7738948SN/A 7748948SN/Astd::pair<MemCmd, Tick> 77510405Sandreas.hansson@arm.comCoherentXBar::forwardAtomic(PacketPtr pkt, PortID exclude_slave_port_id, 77610402SN/A PortID source_master_port_id, 77710888Sandreas.hansson@arm.com const std::vector<QueuedSlavePort*>& dests) 7788948SN/A{ 7799032SN/A // the packet may be changed on snoops, record the original 7809032SN/A // command to enable us to restore it between snoops so that 7818948SN/A // additional snoops can take place properly 7824626SN/A MemCmd orig_cmd = pkt->cmd; 7834879SN/A MemCmd snoop_response_cmd = MemCmd::InvalidCmd; 7844879SN/A Tick snoop_response_latency = 0; 7853662SN/A 7869524SN/A // snoops should only happen if the system isn't bypassing caches 7879524SN/A assert(!system->bypassCaches()); 7889524SN/A 78910401SN/A unsigned fanout = 0; 79010401SN/A 79110405Sandreas.hansson@arm.com for (const auto& p: dests) { 7928915SN/A // we could have gotten this request from a snooping master 7938915SN/A // (corresponding to our own slave port that is also in 7948915SN/A // snoopPorts) and should not send it back to where it came 7958915SN/A // from 79610402SN/A if (exclude_slave_port_id != InvalidPortID && 79710402SN/A p->getId() == exclude_slave_port_id) 79810402SN/A continue; 79910401SN/A 80010402SN/A Tick latency = p->sendAtomicSnoop(pkt); 80110402SN/A fanout++; 80210402SN/A 80310402SN/A // in contrast to a functional access, we have to keep on 80410402SN/A // going as all snoopers must be updated even if we get a 80510402SN/A // response 80610402SN/A if (!pkt->isResponse()) 80710402SN/A continue; 80810402SN/A 80910402SN/A // response from snoop agent 81010402SN/A assert(pkt->cmd != orig_cmd); 81111284Sandreas.hansson@arm.com assert(pkt->cacheResponding()); 81210402SN/A // should only happen once 81310402SN/A assert(snoop_response_cmd == MemCmd::InvalidCmd); 81410402SN/A // save response state 81510402SN/A snoop_response_cmd = pkt->cmd; 81610402SN/A snoop_response_latency = latency; 81710402SN/A 81810402SN/A if (snoopFilter) { 81910402SN/A // Handle responses by the snoopers and differentiate between 82010402SN/A // responses to requests from above and snoops from below 82110402SN/A if (source_master_port_id != InvalidPortID) { 82210402SN/A // Getting a response for a snoop from below 82310402SN/A assert(exclude_slave_port_id == InvalidPortID); 82410402SN/A snoopFilter->updateSnoopForward(pkt, *p, 82510402SN/A *masterPorts[source_master_port_id]); 82610402SN/A } else { 82710402SN/A // Getting a response for a request from above 82810402SN/A assert(source_master_port_id == InvalidPortID); 82910402SN/A snoopFilter->updateSnoopResponse(pkt, *p, 83010402SN/A *slavePorts[exclude_slave_port_id]); 8314626SN/A } 8324626SN/A } 83310402SN/A // restore original packet state for remaining snoopers 83410402SN/A pkt->cmd = orig_cmd; 8354626SN/A } 8364626SN/A 83710401SN/A // Stats for fanout 83810401SN/A snoopFanout.sample(fanout); 83910401SN/A 8408948SN/A // the packet is restored as part of the loop and any potential 8418948SN/A // snoop response is part of the returned pair 8428948SN/A return std::make_pair(snoop_response_cmd, snoop_response_latency); 8432497SN/A} 8442497SN/A 8452497SN/Avoid 84610405Sandreas.hansson@arm.comCoherentXBar::recvFunctional(PacketPtr pkt, PortID slave_port_id) 8472497SN/A{ 8488663SN/A if (!pkt->isPrint()) { 8498663SN/A // don't do DPRINTFs on PrintReq as it clutters up the output 85010405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, 8518949SN/A "recvFunctional: packet src %s addr 0x%x cmd %s\n", 8529032SN/A slavePorts[slave_port_id]->name(), pkt->getAddr(), 8538663SN/A pkt->cmdString()); 8548663SN/A } 8558663SN/A 85610821Sandreas.hansson@arm.com if (!system->bypassCaches()) { 8578979SN/A // forward to all snoopers but the source 8589032SN/A forwardFunctional(pkt, slave_port_id); 8598979SN/A } 8604912SN/A 8618948SN/A // there is no need to continue if the snooping has found what we 8628948SN/A // were looking for and the packet is already a response 8638948SN/A if (!pkt->isResponse()) { 86410888Sandreas.hansson@arm.com // since our slave ports are queued ports we need to check them as well 86510888Sandreas.hansson@arm.com for (const auto& p : slavePorts) { 86610888Sandreas.hansson@arm.com // if we find a response that has the data, then the 86710888Sandreas.hansson@arm.com // downstream caches/memories may be out of date, so simply stop 86810888Sandreas.hansson@arm.com // here 86910888Sandreas.hansson@arm.com if (p->checkFunctional(pkt)) { 87010888Sandreas.hansson@arm.com if (pkt->needsResponse()) 87110888Sandreas.hansson@arm.com pkt->makeResponse(); 87210888Sandreas.hansson@arm.com return; 87310888Sandreas.hansson@arm.com } 87410888Sandreas.hansson@arm.com } 87510888Sandreas.hansson@arm.com 8769031SN/A PortID dest_id = findPort(pkt->getAddr()); 8778948SN/A 8788948SN/A masterPorts[dest_id]->sendFunctional(pkt); 8798948SN/A } 8808948SN/A} 8818948SN/A 8828948SN/Avoid 88310405Sandreas.hansson@arm.comCoherentXBar::recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id) 8848948SN/A{ 8858948SN/A if (!pkt->isPrint()) { 8868948SN/A // don't do DPRINTFs on PrintReq as it clutters up the output 88710405Sandreas.hansson@arm.com DPRINTF(CoherentXBar, 8888949SN/A "recvFunctionalSnoop: packet src %s addr 0x%x cmd %s\n", 8899032SN/A masterPorts[master_port_id]->name(), pkt->getAddr(), 8908948SN/A pkt->cmdString()); 8918948SN/A } 8928948SN/A 89311188Sandreas.sandberg@arm.com for (const auto& p : slavePorts) { 89411188Sandreas.sandberg@arm.com if (p->checkFunctional(pkt)) { 89511188Sandreas.sandberg@arm.com if (pkt->needsResponse()) 89611188Sandreas.sandberg@arm.com pkt->makeResponse(); 89711188Sandreas.sandberg@arm.com return; 89811188Sandreas.sandberg@arm.com } 89911188Sandreas.sandberg@arm.com } 90011188Sandreas.sandberg@arm.com 9018948SN/A // forward to all snoopers 9029031SN/A forwardFunctional(pkt, InvalidPortID); 9038948SN/A} 9048948SN/A 9058948SN/Avoid 90610405Sandreas.hansson@arm.comCoherentXBar::forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id) 9078948SN/A{ 9089524SN/A // snoops should only happen if the system isn't bypassing caches 9099524SN/A assert(!system->bypassCaches()); 9109524SN/A 91110405Sandreas.hansson@arm.com for (const auto& p: snoopPorts) { 9128915SN/A // we could have gotten this request from a snooping master 9138915SN/A // (corresponding to our own slave port that is also in 9148915SN/A // snoopPorts) and should not send it back to where it came 9158915SN/A // from 9169031SN/A if (exclude_slave_port_id == InvalidPortID || 9178948SN/A p->getId() != exclude_slave_port_id) 9188948SN/A p->sendFunctionalSnoop(pkt); 9198915SN/A 9208948SN/A // if we get a response we are done 9218948SN/A if (pkt->isResponse()) { 9228948SN/A break; 9238915SN/A } 9243650SN/A } 9252497SN/A} 9262497SN/A 92711334Sandreas.hansson@arm.combool 92811334Sandreas.hansson@arm.comCoherentXBar::sinkPacket(const PacketPtr pkt) const 92911334Sandreas.hansson@arm.com{ 93011334Sandreas.hansson@arm.com // we can sink the packet if: 93111334Sandreas.hansson@arm.com // 1) the crossbar is the point of coherency, and a cache is 93211334Sandreas.hansson@arm.com // responding after being snooped 93311334Sandreas.hansson@arm.com // 2) the crossbar is the point of coherency, and the packet is a 93411334Sandreas.hansson@arm.com // coherency packet (not a read or a write) that does not 93511334Sandreas.hansson@arm.com // require a response 93611334Sandreas.hansson@arm.com // 3) this is a clean evict or clean writeback, but the packet is 93711334Sandreas.hansson@arm.com // found in a cache above this crossbar 93811334Sandreas.hansson@arm.com // 4) a cache is responding after being snooped, and the packet 93911334Sandreas.hansson@arm.com // either does not need the block to be writable, or the cache 94011334Sandreas.hansson@arm.com // that has promised to respond (setting the cache responding 94111334Sandreas.hansson@arm.com // flag) is providing writable and thus had a Modified block, 94211334Sandreas.hansson@arm.com // and no further action is needed 94311334Sandreas.hansson@arm.com return (pointOfCoherency && pkt->cacheResponding()) || 94411334Sandreas.hansson@arm.com (pointOfCoherency && !(pkt->isRead() || pkt->isWrite()) && 94511334Sandreas.hansson@arm.com !pkt->needsResponse()) || 94611334Sandreas.hansson@arm.com (pkt->isCleanEviction() && pkt->isBlockCached()) || 94711334Sandreas.hansson@arm.com (pkt->cacheResponding() && 94811334Sandreas.hansson@arm.com (!pkt->needsWritable() || pkt->responderHadWritable())); 94911334Sandreas.hansson@arm.com} 95011334Sandreas.hansson@arm.com 9519712SN/Avoid 95210405Sandreas.hansson@arm.comCoherentXBar::regStats() 9539712SN/A{ 95410405Sandreas.hansson@arm.com // register the stats of the base class and our layers 95510405Sandreas.hansson@arm.com BaseXBar::regStats(); 95610405Sandreas.hansson@arm.com for (auto l: reqLayers) 95710405Sandreas.hansson@arm.com l->regStats(); 95810405Sandreas.hansson@arm.com for (auto l: respLayers) 95910405Sandreas.hansson@arm.com l->regStats(); 96010405Sandreas.hansson@arm.com for (auto l: snoopLayers) 96110405Sandreas.hansson@arm.com l->regStats(); 9629712SN/A 96310405Sandreas.hansson@arm.com snoops 96410405Sandreas.hansson@arm.com .name(name() + ".snoops") 96510401SN/A .desc("Total snoops (count)") 96610401SN/A ; 96710401SN/A 96810401SN/A snoopFanout 96910401SN/A .init(0, snoopPorts.size(), 1) 97010401SN/A .name(name() + ".snoop_fanout") 97110401SN/A .desc("Request fanout histogram") 97210401SN/A ; 9739712SN/A} 9749712SN/A 97510405Sandreas.hansson@arm.comCoherentXBar * 97610405Sandreas.hansson@arm.comCoherentXBarParams::create() 9772497SN/A{ 97810405Sandreas.hansson@arm.com return new CoherentXBar(this); 9792497SN/A} 980