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+
+/*
+ * 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.
+ */
+
+/**
+ * @file Definition of a simple bus bridge without buffering.
+ */
+
+
+#include "base/trace.hh"
+#include "mem/bridge.hh"
+#include "sim/builder.hh"
+
+void
+Bridge::init()
+{
+ // Make sure that both sides are connected to.
+ if (sideA == NULL || sideB == NULL)
+ panic("Both ports of bus bridge are not connected to a bus.\n");
+}
+
+
+/** Function called by the port when the bus is recieving a Timing
+ * transaction.*/
+bool
+Bridge::recvTiming(Packet &pkt, Side id)
+{
+ if (blockedA && id == SideA)
+ return false;
+ if (blockedB && id == SideB)
+ return false;
+
+ if (delay) {
+ if (!sendEvent.scheduled())
+ sendEvent.schedule(curTick + delay);
+ if (id == SideA) {
+ inboundA.push_back(std::make_pair<Packet*, Tick>(&pkt, curTick));
+ blockCheck(SideA);
+ } else {
+ inboundB.push_back(std::make_pair<Packet*, Tick>(&pkt, curTick));
+ blockCheck(SideB);
+ }
+ } else {
+ if (id == SideB) {
+ sideA->sendPkt(pkt);
+ blockCheck(SideB);
+ } else {
+ sideB->sendPkt(pkt);
+ blockCheck(SideA);
+ }
+ }
+ return true;
+
+}
+
+void
+Bridge::blockCheck(Side id)
+{
+ /* Check that we still have buffer space available. */
+ if (id == SideB) {
+ if (sideA->numQueued() + inboundB.size() >= queueSizeA && !blockedB) {
+ sideB->sendStatusChange(Port::Blocked);
+ blockedB = true;
+ } else if (sideA->numQueued() + inboundB.size() < queueSizeA && blockedB) {
+ sideB->sendStatusChange(Port::Unblocked);
+ blockedB = false;
+ }
+ } else {
+ if (sideB->numQueued() + inboundA.size() >= queueSizeB && !blockedA) {
+ sideA->sendStatusChange(Port::Blocked);
+ blockedA = true;
+ } else if (sideB->numQueued() + inboundA.size() < queueSizeB && blockedA) {
+ sideA->sendStatusChange(Port::Unblocked);
+ blockedA = false;
+ }
+ }
+}
+
+void Bridge::timerEvent()
+{
+ Tick t = 0;
+
+ assert(inboundA.size() || inboundB.size());
+ if (inboundA.size()) {
+ while (inboundA.front().second <= curTick + delay){
+ sideB->sendPkt(inboundA.front());
+ inboundA.pop_front();
+ }
+ if (inboundA.size())
+ t = inboundA.front().second + delay;
+ }
+ if (inboundB.size()) {
+ while (inboundB.front().second <= curTick + delay){
+ sideB->sendPkt(inboundA.front());
+ inboundB.pop_front();
+ }
+ if (inboundB.size())
+ if (t == 0)
+ t = inboundB.front().second + delay;
+ else
+ t = std::min(t,inboundB.front().second + delay);
+ } else {
+ panic("timerEvent() called but nothing to do?");
+ }
+
+ if (t != 0)
+ sendEvent.schedule(t);
+}
+
+
+void
+Bridge::BridgePort::sendPkt(Packet &pkt)
+{
+ if (!sendTiming(pkt))
+ outbound.push_back(std::make_pair<Packet*,Tick>(&pkt, curTick));
+}
+
+void
+Bridge::BridgePort::sendPkt(std::pair<Packet*, Tick> p)
+{
+ if (!sendTiming(*p.first))
+ outbound.push_back(p);
+}
+
+
+Packet *
+Bridge::BridgePort::recvRetry()
+{
+ Packet *pkt;
+ assert(outbound.size() > 0);
+ assert(outbound.front().second >= curTick + bridge->delay);
+ pkt = outbound.front().first;
+ outbound.pop_front();
+ bridge->blockCheck(side);
+ return pkt;
+}
+
+/** Function called by the port when the bus is recieving a Atomic
+ * transaction.*/
+Tick
+Bridge::recvAtomic(Packet &pkt, Side id)
+{
+ pkt.time += delay;
+
+ if (id == SideA)
+ return sideB->sendAtomic(pkt);
+ else
+ return sideA->sendAtomic(pkt);
+}
+
+/** Function called by the port when the bus is recieving a Functional
+ * transaction.*/
+void
+Bridge::recvFunctional(Packet &pkt, Side id)
+{
+ pkt.time += delay;
+ std::list<std::pair<Packet*, Tick> >::iterator i;
+ bool pktContinue = true;
+
+ for(i = inboundA.begin(); i != inboundA.end(); ++i) {
+ if (pkt.intersect(i->first)) {
+ pktContinue &= fixPacket(pkt, *i->first);
+ }
+ }
+
+ for(i = inboundB.begin(); i != inboundB.end(); ++i) {
+ if (pkt.intersect(i->first)) {
+ pktContinue &= fixPacket(pkt, *i->first);
+ }
+ }
+
+ for(i = sideA->outbound.begin(); i != sideA->outbound.end(); ++i) {
+ if (pkt.intersect(i->first)) {
+ pktContinue &= fixPacket(pkt, *i->first);
+ }
+ }
+
+ for(i = sideB->outbound.begin(); i != sideB->outbound.end(); ++i) {
+ if (pkt.intersect(i->first)) {
+ pktContinue &= fixPacket(pkt, *i->first);
+ }
+ }
+
+ if (pktContinue) {
+ if (id == SideA)
+ sideB->sendFunctional(pkt);
+ else
+ sideA->sendFunctional(pkt);
+ }
+}
+
+/** Function called by the port when the bus is recieving a status change.*/
+void
+Bridge::recvStatusChange(Port::Status status, Side id)
+{
+ if (status == Port::Blocked || status == Port::Unblocked)
+ return ;
+
+ if (id == SideA)
+ sideB->sendStatusChange(status);
+ else
+ sideA->sendStatusChange(status);
+}
+
+void
+Bridge::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, Side id)
+{
+ if (id == SideA)
+ sideB->getPeerAddressRanges(resp, snoop);
+ else
+ sideA->getPeerAddressRanges(resp, snoop);
+}
+
+BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge)
+
+ Param<int> queue_size_a;
+ Param<int> queue_size_b;
+ Param<Tick> delay;
+ Param<bool> write_ack;
+
+END_DECLARE_SIM_OBJECT_PARAMS(Bridge)
+
+BEGIN_INIT_SIM_OBJECT_PARAMS(Bridge)
+
+ INIT_PARAM(queue_size_a, "The size of the queue for data coming into side a"),
+ INIT_PARAM(queue_size_b, "The size of the queue for data coming into side b"),
+ INIT_PARAM(delay, "The miminum delay to cross this bridge"),
+ INIT_PARAM(write_ack, "Acknowledge any writes that are received.")
+
+END_INIT_SIM_OBJECT_PARAMS(Bridge)
+
+CREATE_SIM_OBJECT(Bridge)
+{
+ return new Bridge(getInstanceName(), queue_size_a, queue_size_b, delay,
+ write_ack);
+}
+
+REGISTER_SIM_OBJECT("Bridge", Bridge)
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