| /* |
| * Copyright (c) 2011-2012 ARM Limited |
| * All rights reserved |
| * |
| * The license below extends only to copyright in the software and shall |
| * not be construed as granting a license to any other intellectual |
| * property including but not limited to intellectual property relating |
| * to a hardware implementation of the functionality of the software |
| * licensed hereunder. You may use the software subject to the license |
| * terms below provided that you ensure that this notice is replicated |
| * unmodified and in its entirety in all distributions of the software, |
| * modified or unmodified, in source code or in binary form. |
| * |
| * Copyright (c) 2006 The Regents of The University of Michigan |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer; |
| * redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution; |
| * neither the name of the copyright holders nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * Authors: Ali Saidi |
| * Andreas Hansson |
| * William Wang |
| */ |
| |
| /** |
| * @file |
| * Definition of a bus object. |
| */ |
| |
| #include "base/misc.hh" |
| #include "base/trace.hh" |
| #include "debug/BusAddrRanges.hh" |
| #include "debug/CoherentBus.hh" |
| #include "mem/coherent_bus.hh" |
| #include "sim/system.hh" |
| |
| CoherentBus::CoherentBus(const CoherentBusParams *p) |
| : BaseBus(p), |
| reqLayer(*this, ".reqLayer", p->port_master_connection_count + |
| p->port_default_connection_count), |
| respLayer(*this, ".respLayer", p->port_slave_connection_count), |
| snoopRespLayer(*this, ".snoopRespLayer", |
| p->port_master_connection_count + |
| p->port_default_connection_count), |
| system(p->system) |
| { |
| // create the ports based on the size of the master and slave |
| // vector ports, and the presence of the default port, the ports |
| // are enumerated starting from zero |
| for (int i = 0; i < p->port_master_connection_count; ++i) { |
| std::string portName = csprintf("%s.master[%d]", name(), i); |
| MasterPort* bp = new CoherentBusMasterPort(portName, *this, i); |
| masterPorts.push_back(bp); |
| } |
| |
| // see if we have a default slave device connected and if so add |
| // our corresponding master port |
| if (p->port_default_connection_count) { |
| defaultPortID = masterPorts.size(); |
| std::string portName = name() + ".default"; |
| MasterPort* bp = new CoherentBusMasterPort(portName, *this, |
| defaultPortID); |
| masterPorts.push_back(bp); |
| } |
| |
| // create the slave ports, once again starting at zero |
| for (int i = 0; i < p->port_slave_connection_count; ++i) { |
| std::string portName = csprintf("%s.slave[%d]", name(), i); |
| SlavePort* bp = new CoherentBusSlavePort(portName, *this, i); |
| slavePorts.push_back(bp); |
| } |
| |
| clearPortCache(); |
| } |
| |
| void |
| CoherentBus::init() |
| { |
| // the base class is responsible for determining the block size |
| BaseBus::init(); |
| |
| // iterate over our slave ports and determine which of our |
| // neighbouring master ports are snooping and add them as snoopers |
| for (SlavePortConstIter p = slavePorts.begin(); p != slavePorts.end(); |
| ++p) { |
| // check if the connected master port is snooping |
| if ((*p)->isSnooping()) { |
| DPRINTF(BusAddrRanges, "Adding snooping master %s\n", |
| (*p)->getMasterPort().name()); |
| snoopPorts.push_back(*p); |
| } |
| } |
| |
| if (snoopPorts.empty()) |
| warn("CoherentBus %s has no snooping ports attached!\n", name()); |
| } |
| |
| bool |
| CoherentBus::recvTimingReq(PacketPtr pkt, PortID slave_port_id) |
| { |
| // determine the source port based on the id |
| SlavePort *src_port = slavePorts[slave_port_id]; |
| |
| // remember if the packet is an express snoop |
| bool is_express_snoop = pkt->isExpressSnoop(); |
| |
| // determine the destination based on the address |
| PortID dest_port_id = findPort(pkt->getAddr()); |
| |
| // test if the bus should be considered occupied for the current |
| // port, and exclude express snoops from the check |
| if (!is_express_snoop && !reqLayer.tryTiming(src_port, dest_port_id)) { |
| DPRINTF(CoherentBus, "recvTimingReq: src %s %s 0x%x BUS BUSY\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| return false; |
| } |
| |
| DPRINTF(CoherentBus, "recvTimingReq: src %s %s expr %d 0x%x\n", |
| src_port->name(), pkt->cmdString(), is_express_snoop, |
| pkt->getAddr()); |
| |
| // set the source port for routing of the response |
| pkt->setSrc(slave_port_id); |
| |
| calcPacketTiming(pkt); |
| Tick packetFinishTime = pkt->busLastWordDelay + curTick(); |
| |
| // uncacheable requests need never be snooped |
| if (!pkt->req->isUncacheable() && !system->bypassCaches()) { |
| // the packet is a memory-mapped request and should be |
| // broadcasted to our snoopers but the source |
| forwardTiming(pkt, slave_port_id); |
| } |
| |
| // remember if we add an outstanding req so we can undo it if |
| // necessary, if the packet needs a response, we should add it |
| // as outstanding and express snoops never fail so there is |
| // not need to worry about them |
| bool add_outstanding = !is_express_snoop && pkt->needsResponse(); |
| |
| // keep track that we have an outstanding request packet |
| // matching this request, this is used by the coherency |
| // mechanism in determining what to do with snoop responses |
| // (in recvTimingSnoop) |
| if (add_outstanding) { |
| // we should never have an exsiting request outstanding |
| assert(outstandingReq.find(pkt->req) == outstandingReq.end()); |
| outstandingReq.insert(pkt->req); |
| } |
| |
| // since it is a normal request, attempt to send the packet |
| bool success = masterPorts[dest_port_id]->sendTimingReq(pkt); |
| |
| // if this is an express snoop, we are done at this point |
| if (is_express_snoop) { |
| assert(success); |
| } else { |
| // for normal requests, check if successful |
| if (!success) { |
| // inhibited packets should never be forced to retry |
| assert(!pkt->memInhibitAsserted()); |
| |
| // if it was added as outstanding and the send failed, then |
| // erase it again |
| if (add_outstanding) |
| outstandingReq.erase(pkt->req); |
| |
| // undo the calculation so we can check for 0 again |
| pkt->busFirstWordDelay = pkt->busLastWordDelay = 0; |
| |
| DPRINTF(CoherentBus, "recvTimingReq: src %s %s 0x%x RETRY\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| |
| // update the bus state and schedule an idle event |
| reqLayer.failedTiming(src_port, dest_port_id, |
| clockEdge(Cycles(headerCycles))); |
| } else { |
| // update the bus state and schedule an idle event |
| reqLayer.succeededTiming(packetFinishTime); |
| } |
| } |
| |
| return success; |
| } |
| |
| bool |
| CoherentBus::recvTimingResp(PacketPtr pkt, PortID master_port_id) |
| { |
| // determine the source port based on the id |
| MasterPort *src_port = masterPorts[master_port_id]; |
| |
| // test if the bus should be considered occupied for the current |
| // port |
| if (!respLayer.tryTiming(src_port, pkt->getDest())) { |
| DPRINTF(CoherentBus, "recvTimingResp: src %s %s 0x%x BUSY\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| return false; |
| } |
| |
| DPRINTF(CoherentBus, "recvTimingResp: src %s %s 0x%x\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| |
| calcPacketTiming(pkt); |
| Tick packetFinishTime = pkt->busLastWordDelay + curTick(); |
| |
| // the packet is a normal response to a request that we should |
| // have seen passing through the bus |
| assert(outstandingReq.find(pkt->req) != outstandingReq.end()); |
| |
| // remove it as outstanding |
| outstandingReq.erase(pkt->req); |
| |
| // send the packet to the destination through one of our slave |
| // ports, as determined by the destination field |
| bool success M5_VAR_USED = slavePorts[pkt->getDest()]->sendTimingResp(pkt); |
| |
| // currently it is illegal to block responses... can lead to |
| // deadlock |
| assert(success); |
| |
| respLayer.succeededTiming(packetFinishTime); |
| |
| return true; |
| } |
| |
| void |
| CoherentBus::recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id) |
| { |
| DPRINTF(CoherentBus, "recvTimingSnoopReq: src %s %s 0x%x\n", |
| masterPorts[master_port_id]->name(), pkt->cmdString(), |
| pkt->getAddr()); |
| |
| // we should only see express snoops from caches |
| assert(pkt->isExpressSnoop()); |
| |
| // set the source port for routing of the response |
| pkt->setSrc(master_port_id); |
| |
| // forward to all snoopers |
| forwardTiming(pkt, InvalidPortID); |
| |
| // a snoop request came from a connected slave device (one of |
| // our master ports), and if it is not coming from the slave |
| // device responsible for the address range something is |
| // wrong, hence there is nothing further to do as the packet |
| // would be going back to where it came from |
| assert(master_port_id == findPort(pkt->getAddr())); |
| } |
| |
| bool |
| CoherentBus::recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id) |
| { |
| // determine the source port based on the id |
| SlavePort* src_port = slavePorts[slave_port_id]; |
| |
| // test if the bus should be considered occupied for the current |
| // port, do not use the destination port in the check as we do not |
| // know yet if it is to be passed on as a snoop response or normal |
| // response and we never block on either |
| if (!snoopRespLayer.tryTiming(src_port, InvalidPortID)) { |
| DPRINTF(CoherentBus, "recvTimingSnoopResp: src %s %s 0x%x BUSY\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| return false; |
| } |
| |
| DPRINTF(CoherentBus, "recvTimingSnoop: src %s %s 0x%x\n", |
| src_port->name(), pkt->cmdString(), pkt->getAddr()); |
| |
| // get the destination from the packet |
| PortID dest = pkt->getDest(); |
| |
| // responses are never express snoops |
| assert(!pkt->isExpressSnoop()); |
| |
| calcPacketTiming(pkt); |
| Tick packetFinishTime = pkt->busLastWordDelay + curTick(); |
| |
| // determine if the response is from a snoop request we |
| // created as the result of a normal request (in which case it |
| // should be in the outstandingReq), or if we merely forwarded |
| // someone else's snoop request |
| if (outstandingReq.find(pkt->req) == outstandingReq.end()) { |
| // this is a snoop response to a snoop request we |
| // forwarded, e.g. coming from the L1 and going to the L2 |
| // this should be forwarded as a snoop response |
| bool success M5_VAR_USED = masterPorts[dest]->sendTimingSnoopResp(pkt); |
| assert(success); |
| } else { |
| // we got a snoop response on one of our slave ports, |
| // i.e. from a coherent master connected to the bus, and |
| // since we created the snoop request as part of |
| // recvTiming, this should now be a normal response again |
| outstandingReq.erase(pkt->req); |
| |
| // this is a snoop response from a coherent master, with a |
| // destination field set on its way through the bus as |
| // request, hence it should never go back to where the |
| // snoop response came from, but instead to where the |
| // original request came from |
| assert(slave_port_id != dest); |
| |
| // as a normal response, it should go back to a master |
| // through one of our slave ports |
| bool success M5_VAR_USED = slavePorts[dest]->sendTimingResp(pkt); |
| |
| // currently it is illegal to block responses... can lead |
| // to deadlock |
| assert(success); |
| } |
| |
| snoopRespLayer.succeededTiming(packetFinishTime); |
| |
| return true; |
| } |
| |
| |
| void |
| CoherentBus::forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id) |
| { |
| // snoops should only happen if the system isn't bypassing caches |
| assert(!system->bypassCaches()); |
| |
| for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) { |
| SlavePort *p = *s; |
| // we could have gotten this request from a snooping master |
| // (corresponding to our own slave port that is also in |
| // snoopPorts) and should not send it back to where it came |
| // from |
| if (exclude_slave_port_id == InvalidPortID || |
| p->getId() != exclude_slave_port_id) { |
| // cache is not allowed to refuse snoop |
| p->sendTimingSnoopReq(pkt); |
| } |
| } |
| } |
| |
| void |
| CoherentBus::recvRetry(PortID master_port_id) |
| { |
| // responses and snoop responses never block on forwarding them, |
| // so the retry will always be coming from a port to which we |
| // tried to forward a request |
| reqLayer.recvRetry(master_port_id); |
| } |
| |
| Tick |
| CoherentBus::recvAtomic(PacketPtr pkt, PortID slave_port_id) |
| { |
| DPRINTF(CoherentBus, "recvAtomic: packet src %s addr 0x%x cmd %s\n", |
| slavePorts[slave_port_id]->name(), pkt->getAddr(), |
| pkt->cmdString()); |
| |
| MemCmd snoop_response_cmd = MemCmd::InvalidCmd; |
| Tick snoop_response_latency = 0; |
| |
| // uncacheable requests need never be snooped |
| if (!pkt->req->isUncacheable() && !system->bypassCaches()) { |
| // forward to all snoopers but the source |
| std::pair<MemCmd, Tick> snoop_result = |
| forwardAtomic(pkt, slave_port_id); |
| snoop_response_cmd = snoop_result.first; |
| snoop_response_latency = snoop_result.second; |
| } |
| |
| // even if we had a snoop response, we must continue and also |
| // perform the actual request at the destination |
| PortID dest_id = findPort(pkt->getAddr()); |
| |
| // forward the request to the appropriate destination |
| Tick response_latency = masterPorts[dest_id]->sendAtomic(pkt); |
| |
| // if we got a response from a snooper, restore it here |
| if (snoop_response_cmd != MemCmd::InvalidCmd) { |
| // no one else should have responded |
| assert(!pkt->isResponse()); |
| pkt->cmd = snoop_response_cmd; |
| response_latency = snoop_response_latency; |
| } |
| |
| // @todo: Not setting first-word time |
| pkt->busLastWordDelay = response_latency; |
| return response_latency; |
| } |
| |
| Tick |
| CoherentBus::recvAtomicSnoop(PacketPtr pkt, PortID master_port_id) |
| { |
| DPRINTF(CoherentBus, "recvAtomicSnoop: packet src %s addr 0x%x cmd %s\n", |
| masterPorts[master_port_id]->name(), pkt->getAddr(), |
| pkt->cmdString()); |
| |
| // forward to all snoopers |
| std::pair<MemCmd, Tick> snoop_result = |
| forwardAtomic(pkt, InvalidPortID); |
| MemCmd snoop_response_cmd = snoop_result.first; |
| Tick snoop_response_latency = snoop_result.second; |
| |
| if (snoop_response_cmd != MemCmd::InvalidCmd) |
| pkt->cmd = snoop_response_cmd; |
| |
| // @todo: Not setting first-word time |
| pkt->busLastWordDelay = snoop_response_latency; |
| return snoop_response_latency; |
| } |
| |
| std::pair<MemCmd, Tick> |
| CoherentBus::forwardAtomic(PacketPtr pkt, PortID exclude_slave_port_id) |
| { |
| // the packet may be changed on snoops, record the original |
| // command to enable us to restore it between snoops so that |
| // additional snoops can take place properly |
| MemCmd orig_cmd = pkt->cmd; |
| MemCmd snoop_response_cmd = MemCmd::InvalidCmd; |
| Tick snoop_response_latency = 0; |
| |
| // snoops should only happen if the system isn't bypassing caches |
| assert(!system->bypassCaches()); |
| |
| for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) { |
| SlavePort *p = *s; |
| // we could have gotten this request from a snooping master |
| // (corresponding to our own slave port that is also in |
| // snoopPorts) and should not send it back to where it came |
| // from |
| if (exclude_slave_port_id == InvalidPortID || |
| p->getId() != exclude_slave_port_id) { |
| Tick latency = p->sendAtomicSnoop(pkt); |
| // in contrast to a functional access, we have to keep on |
| // going as all snoopers must be updated even if we get a |
| // response |
| if (pkt->isResponse()) { |
| // response from snoop agent |
| assert(pkt->cmd != orig_cmd); |
| assert(pkt->memInhibitAsserted()); |
| // should only happen once |
| assert(snoop_response_cmd == MemCmd::InvalidCmd); |
| // save response state |
| snoop_response_cmd = pkt->cmd; |
| snoop_response_latency = latency; |
| // restore original packet state for remaining snoopers |
| pkt->cmd = orig_cmd; |
| } |
| } |
| } |
| |
| // the packet is restored as part of the loop and any potential |
| // snoop response is part of the returned pair |
| return std::make_pair(snoop_response_cmd, snoop_response_latency); |
| } |
| |
| void |
| CoherentBus::recvFunctional(PacketPtr pkt, PortID slave_port_id) |
| { |
| if (!pkt->isPrint()) { |
| // don't do DPRINTFs on PrintReq as it clutters up the output |
| DPRINTF(CoherentBus, |
| "recvFunctional: packet src %s addr 0x%x cmd %s\n", |
| slavePorts[slave_port_id]->name(), pkt->getAddr(), |
| pkt->cmdString()); |
| } |
| |
| // uncacheable requests need never be snooped |
| if (!pkt->req->isUncacheable() && !system->bypassCaches()) { |
| // forward to all snoopers but the source |
| forwardFunctional(pkt, slave_port_id); |
| } |
| |
| // there is no need to continue if the snooping has found what we |
| // were looking for and the packet is already a response |
| if (!pkt->isResponse()) { |
| PortID dest_id = findPort(pkt->getAddr()); |
| |
| masterPorts[dest_id]->sendFunctional(pkt); |
| } |
| } |
| |
| void |
| CoherentBus::recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id) |
| { |
| if (!pkt->isPrint()) { |
| // don't do DPRINTFs on PrintReq as it clutters up the output |
| DPRINTF(CoherentBus, |
| "recvFunctionalSnoop: packet src %s addr 0x%x cmd %s\n", |
| masterPorts[master_port_id]->name(), pkt->getAddr(), |
| pkt->cmdString()); |
| } |
| |
| // forward to all snoopers |
| forwardFunctional(pkt, InvalidPortID); |
| } |
| |
| void |
| CoherentBus::forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id) |
| { |
| // snoops should only happen if the system isn't bypassing caches |
| assert(!system->bypassCaches()); |
| |
| for (SlavePortIter s = snoopPorts.begin(); s != snoopPorts.end(); ++s) { |
| SlavePort *p = *s; |
| // we could have gotten this request from a snooping master |
| // (corresponding to our own slave port that is also in |
| // snoopPorts) and should not send it back to where it came |
| // from |
| if (exclude_slave_port_id == InvalidPortID || |
| p->getId() != exclude_slave_port_id) |
| p->sendFunctionalSnoop(pkt); |
| |
| // if we get a response we are done |
| if (pkt->isResponse()) { |
| break; |
| } |
| } |
| } |
| |
| unsigned int |
| CoherentBus::drain(DrainManager *dm) |
| { |
| // sum up the individual layers |
| return reqLayer.drain(dm) + respLayer.drain(dm) + snoopRespLayer.drain(dm); |
| } |
| |
| CoherentBus * |
| CoherentBusParams::create() |
| { |
| return new CoherentBus(this); |
| } |