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// Copyright 2009-2014 Sandia Coporation.  Under the terms
// of Contract DE-AC04-94AL85000 with Sandia Corporation, the U.S.
// Government retains certain rights in this software.
//
// Copyright (c) 2009-2014, Sandia Corporation
// All rights reserved.
//
// For license information, see the LICENSE file in the current directory.

#include "gem5.hh"

#ifdef fatal  // gem5 sets this
#undef fatal
#endif

#include <base/types.hh>

using namespace SST;
using namespace SST::gem5;
using namespace SST::MemHierarchy;

ExtSlave::ExtSlave(gem5Component *g5c, Output &out,
        ::gem5::ExternalSlave& port, std::string &name) :
    ::gem5::ExternalSlave::Port(name, port),
    comp(g5c), out(out), simPhase(CONSTRUCTION), initPackets(NULL),
    link(comp->configureLink(name, new Event::Handler<ExtSlave>(this,
                                              &ExtSlave::handleEvent)))
{
    if (!link) {
        out.fatal(CALL_INFO, 1, "Failed to configure link %s\n", name.c_str());
    }
}

void
ExtSlave::init(unsigned phase)
{
    simPhase = INIT;
    if (initPackets) {
        while (!initPackets->empty()) {
            link->sendInitData(initPackets->front());
            initPackets->pop_front();
        }
        delete initPackets;
        initPackets = NULL;
    }
}

void
ExtSlave::recvFunctional(::gem5::PacketPtr pkt)
{
    if (simPhase == CONSTRUCTION) {
        if (initPackets == NULL) {
            initPackets = new std::list<MemEvent*>;
        }
        ::gem5::MemCmd::Command pktCmd =
            (::gem5::MemCmd::Command)pkt->cmd.toInt();
        assert(pktCmd == ::gem5::MemCmd::WriteReq);
        ::gem5::Addr a = pkt->getAddr();
        MemEvent* ev = new MemEvent(comp, a, a, GetX);
        ev->setPayload(pkt->getSize(), pkt->getPtr<uint8_t>());
        initPackets->push_back(ev);
    } else {
        panic("Functional accesses not allowed after construction phase");
    }
}

bool
ExtSlave::recvTimingReq(::gem5::PacketPtr pkt)
{
    Command cmd;
    switch ((::gem5::MemCmd::Command)pkt->cmd.toInt()) {
    case ::gem5::MemCmd::HardPFReq:
    case ::gem5::MemCmd::SoftPFReq:
    case ::gem5::MemCmd::LoadLockedReq:
    case ::gem5::MemCmd::ReadExReq:
    case ::gem5::MemCmd::ReadReq:       cmd = GetS;   break;
    case ::gem5::MemCmd::StoreCondReq:
    case ::gem5::MemCmd::WriteReq:      cmd = GetX;   break;
    default:
        out.fatal(CALL_INFO, 1, "Don't know how to convert gem5 packet "
                  "command %s to SST\n", pkt->cmd.toString().c_str());
    }

    auto ev = new MemEvent(comp, pkt->getAddr(), pkt->getAddr(), cmd);
    ev->setPayload(pkt->getSize(), pkt->getPtr<uint8_t>());
    if ((::gem5::MemCmd::Command)pkt->cmd.toInt() ==
        ::gem5::MemCmd::LoadLockedReq) {
        ev->setLoadLink();
    } else if ((::gem5::MemCmd::Command)pkt->cmd.toInt() ==
        ::gem5::MemCmd::StoreCondReq) {
        ev->setStoreConditional();
    }

    if (pkt->req->isLockedRMW())   ev->setFlag(MemEvent::F_LOCKED);
    if (pkt->req->isUncacheable()) ev->setFlag(MemEvent::F_NONCACHEABLE);
    if (pkt->req->hasContextId())  ev->setGroupId(pkt->req->contextId());
// Prefetches not working with SST; it maybe be dropping them, treating them
// as not deserving of responses, or something else -- not sure yet.
//  ev->setPrefetchFlag(pkt->req->isPrefetch());

    if (simPhase == INIT) {
        link->sendInitData(ev);
        delete pkt;
    } else {
        if (pkt->needsResponse()) {
            PacketMap[ev->getID()] = pkt;
        }
        link->send(ev);
    }
    return true;
}


void
ExtSlave::handleEvent(Event* ev)
{
    MemEvent* event = dynamic_cast<MemEvent*>(ev);
    if (!event) {
        out.fatal(CALL_INFO, 1, "ExtSlave handleEvent received non-MemEvent\n");
        delete ev;
        return;
    }
    Event::id_type id = event->getID();

    PacketMap_t::iterator mi = PacketMap.find(id);
    if (mi != PacketMap.end()) { // replying to prior request
        ::gem5::PacketPtr pkt = mi->second;
        PacketMap.erase(mi);

        pkt->makeResponse();  // Convert to a response packet
        pkt->setData(event->getPayload().data());

        // Resolve the success of Store Conditionals
        if (pkt->isLLSC() && pkt->isWrite()) {
            pkt->req->setExtraData(event->isAtomic());
        }

        // Clear out bus delay notifications
        pkt->headerDelay = pkt->payloadDelay = 0;

        if (blocked() || !sendTimingResp(pkt)) {
            respQ.push_back(pkt);
        }
    } else { // we can handle unexpected invalidates, but nothing else.
        Command cmd = event->getCmd();
        assert(cmd == Inv);

        // make Req/Pkt for Snoop/no response needed
        // presently no consideration for masterId, packet type, flags...
        ::gem5::RequestPtr req = std::make_shared<::gem5::Request>(
            event->getAddr(), event->getSize(), 0, 0);

        auto pkt = new ::gem5::Packet(req, ::gem5::MemCmd::InvalidateReq);

        // Clear out bus delay notifications
        pkt->headerDelay = pkt->payloadDelay = 0;

        sendTimingSnoopReq(pkt);
    }
    delete event;
}

void
ExtSlave::recvRespRetry()
{
    while (blocked() && sendTimingResp(respQ.front())) {
        respQ.pop_front();
    }
}