mem: Add ExternalMaster and ExternalSlave ports

This patch adds two MemoryObject's: ExternalMaster and ExternalSlave.
Each object has a single port which can be bound to an externally-
provided bridge to a port of another simulation system at
initialisation.

1 files changed, 252 insertions, 0 deletions

diff --git a/src/mem/external_slave.cc b/src/mem/external_slave.cc
new file mode 100644
index 000000000..c7ad521c9
--- /dev/null
+++ b/src/mem/external_slave.cc
@@ -0,0 +1,252 @@
+/*
+ * Copyright (c) 2012-2014 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.
+ *
+ * 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: Andrew Bardsley
+ */
+
+#include <cctype>
+#include <iomanip>
+
+#include "debug/ExternalPort.hh"
+#include "mem/external_slave.hh"
+
+/** Implement a `stub' port which just responds to requests by printing
+ *  a message.  The stub port can be used to configure and test a system
+ *  where the external port is used for a peripheral before connecting
+ *  the external port */
+class StubSlavePort : public ExternalSlave::Port
+{
+  public:
+    class ResponseEvent : public Event
+    {
+      public:
+        StubSlavePort &owner;
+
+        ResponseEvent(StubSlavePort &owner_) : owner(owner_) { }
+
+        void process();
+    };
+
+    ResponseEvent responseEvent;
+
+    /** Stub can handle a single request at a time.  This will be
+     *  NULL when no packet is in flight */
+    PacketPtr responsePacket;
+
+    /** Received a new request while processing a first.  Need to ask for
+     *  a retry after completing this packet */
+    bool mustRetry;
+
+    StubSlavePort(const std::string &name_,
+        ExternalSlave &owner_) :
+        ExternalSlave::Port(name_, owner_),
+        responseEvent(*this), responsePacket(NULL)
+    { }
+
+    Tick recvAtomic(PacketPtr packet);
+    void recvFunctional(PacketPtr packet);
+    bool recvTimingReq(PacketPtr packet);
+    bool recvTimingSnoopResp(PacketPtr packet);
+    void recvRetry();
+    void recvFunctionalSnoop(PacketPtr packet);
+};
+
+class StubSlavePortHandler : public
+    ExternalSlave::Handler
+{
+  public:
+    ExternalSlave::Port *getExternalPort(
+        const std::string &name_,
+        ExternalSlave &owner,
+        const std::string &port_data)
+    {
+        StringWrap name(name_);
+
+        DPRINTF(ExternalPort, "finding stub port '%s'\n", port_data);
+        return new StubSlavePort(name_, owner);
+    }
+};
+
+Tick
+StubSlavePort::recvAtomic(PacketPtr packet)
+{
+    if (DTRACE(ExternalPort)) {
+        unsigned int M5_VAR_USED size = packet->getSize();
+
+        DPRINTF(ExternalPort, "StubSlavePort: recvAtomic a: 0x%x size: %d"
+            " data: ...\n", packet->getAddr(), size);
+        DDUMP(ExternalPort, packet->getPtr<uint8_t>(), size);
+    }
+
+    return 0;
+}
+
+void
+StubSlavePort::recvFunctional(PacketPtr packet)
+{
+    recvAtomic(packet);
+}
+
+void
+StubSlavePort::ResponseEvent::process()
+{
+    owner.responsePacket->makeResponse();
+    owner.responsePacket->firstWordDelay = 0;
+    owner.responsePacket->lastWordDelay = 0;
+
+    if (owner.sendTimingResp(owner.responsePacket)) {
+        owner.responsePacket = NULL;
+
+        if (owner.mustRetry)
+            owner.sendRetry();
+        owner.mustRetry = false;
+    }
+}
+
+bool
+StubSlavePort::recvTimingReq(PacketPtr packet)
+{
+    if (responsePacket) {
+        mustRetry = true;
+
+        return false;
+    } else {
+        recvAtomic(packet);
+
+        responsePacket = packet;
+        owner.schedule(responseEvent, curTick());
+
+        return true;
+    }
+}
+
+bool
+StubSlavePort::recvTimingSnoopResp(PacketPtr packet)
+{
+    fatal("StubSlavePort: function: %s\n", __func__);
+    return false;
+}
+
+void
+StubSlavePort::recvRetry()
+{
+    assert(responsePacket);
+    /* Stub handles only one response at a time so responseEvent should never
+     *  be scheduled at this point.  Retrys shouldn't need to schedule, we
+     *  can safely send the response here */
+    responseEvent.process();
+}
+
+void
+StubSlavePort::recvFunctionalSnoop(PacketPtr packet)
+{
+    fatal("StubSlavePort: unimplemented function: %s\n", __func__);
+}
+
+std::map<std::string, ExternalSlave::Handler *>
+    ExternalSlave::portHandlers;
+
+AddrRangeList
+ExternalSlave::Port::getAddrRanges() const
+{
+    return owner.addrRanges;
+}
+
+ExternalSlave::ExternalSlave(ExternalSlaveParams *params) :
+    MemObject(params),
+    externalPort(NULL),
+    portName(params->name + ".port"),
+    portType(params->port_type),
+    portData(params->port_data),
+    addrRanges(params->addr_ranges.begin(), params->addr_ranges.end())
+{
+    /* Register the stub handler if it hasn't already been registered */
+    if (portHandlers.find("stub") == portHandlers.end())
+        registerHandler("stub", new StubSlavePortHandler);
+}
+
+BaseSlavePort &
+ExternalSlave::getSlavePort(const std::string &if_name,
+    PortID idx)
+{
+    if (if_name == "port") {
+        DPRINTF(ExternalPort, "Trying to bind external port: %s %s\n",
+            portType, portName);
+
+        if (!externalPort) {
+            auto handlerIter = portHandlers.find(portType);
+
+            if (handlerIter == portHandlers.end())
+                fatal("Can't find port handler type '%s'\n", portType);
+
+            externalPort = portHandlers[portType]->getExternalPort(portName,
+                *this, portData);
+
+            if (!externalPort) {
+                fatal("%s: Can't find external port type: %s"
+                    " port_data: '%s'\n", portName, portType, portData);
+            }
+        }
+        return *externalPort;
+    } else {
+        return MemObject::getSlavePort(if_name, idx);
+    }
+}
+
+void
+ExternalSlave::init()
+{
+    if (!externalPort) {
+        fatal("ExternalSlave %s: externalPort not set!\n", name());
+    } else if (!externalPort->isConnected()) {
+        fatal("ExternalSlave %s is unconnected!\n", name());
+    } else {
+        externalPort->sendRangeChange();
+    }
+}
+
+ExternalSlave *
+ExternalSlaveParams::create()
+{
+    return new ExternalSlave(this);
+}
+
+void
+ExternalSlave::registerHandler(const std::string &handler_name,
+    Handler *handler)
+{
+    portHandlers[handler_name] = handler;
+}