add a bridge object, modify bus object to be able to connect to other buses or bridges without panicing

SConscript:
    add new cc files to scons
mem/bus.cc:
mem/bus.hh:
    implement addressRanges() on the bus.
    propigate address ranges to anyone who is interested stripping out ranges of who your propigating to (to avoid livelock)
mem/packet.hh:
    add intersect function that returns true if two packets touch at least one byte of the same data (for functional access)
    add fixPacket() that will eventually take the correct action giving a timing and functional packet, right now it panics
mem/physical.cc:
    Don't panic if the physical memory recieves a status change, just ignore.

--HG--
extra : convert_revision : d470d51f2fb1db2700ad271e09792315ef33ba01

1 files changed, 263 insertions, 0 deletions

diff --git a/mem/bridge.cc b/mem/bridge.cc
new file mode 100644
index 000000000..d358ef77b
--- /dev/null
+++ b/mem/bridge.cc
@@ -0,0 +1,263 @@
+
+/*
+ * 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)