MEM: Split SimpleTimingPort into PacketQueue and ports

This patch decouples the queueing and the port interactions to
simplify the introduction of the master and slave ports. By separating
the queueing functionality from the port itself, it becomes much
easier to distinguish between master and slave ports, and still retain
the queueing ability for both (without code duplication).

As part of the split into a PacketQueue and a port, there is now also
a hierarchy of two port classes, QueuedPort and SimpleTimingPort. The
QueuedPort is useful for ports that want to leave the packet
transmission of outgoing packets to the queue and is used by both
master and slave ports. The SimpleTimingPort inherits from the
QueuedPort and adds the implemention of recvTiming and recvFunctional
through recvAtomic.

The PioPort and MessagePort are cleaned up as part of the changes.

--HG--
rename : src/mem/tport.cc => src/mem/packet_queue.cc
rename : src/mem/tport.hh => src/mem/packet_queue.hh

1 files changed, 101 insertions, 0 deletions

diff --git a/src/mem/qport.hh b/src/mem/qport.hh
new file mode 100644
index 000000000..39612d22f
--- /dev/null
+++ b/src/mem/qport.hh
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 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.
+ *
+ * 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: Andreas Hansson
+ */
+
+#ifndef __MEM_QPORT_HH__
+#define __MEM_QPORT_HH__
+
+/**
+ * @file
+ * Declaration of the queued port.
+ */
+
+#include "mem/packet_queue.hh"
+#include "mem/port.hh"
+
+/**
+ * A queued port is a port that has an infinite queue for outgoing
+ * packets and thus decouples the module that wants to send
+ * request/responses from the flow control (retry mechanism) of the
+ * port. A queued port can be used by both a master and a slave. The
+ * queue is a parameter to allow tailoring of the queue implementation
+ * (used in the cache).
+ */
+class QueuedPort : public Port
+{
+
+  protected:
+
+    /** Packet queue used to store outgoing requests and responses. */
+    PacketQueue &queue;
+
+     /** This function is notification that the device should attempt to send a
+      * packet again. */
+    virtual void recvRetry() { queue.retry(); }
+
+    virtual void recvRangeChange() { }
+
+  public:
+
+    /**
+     * Create a QueuedPort with a given name, owner, and a supplied
+     * implementation of a packet queue. The external definition of
+     * the queue enables e.g. the cache to implement a specific queue
+     * behaviuor in a subclass, and provide the latter to the
+     * QueuePort constructor.
+     */
+    QueuedPort(const std::string& name, MemObject* owner, PacketQueue &queue) :
+        Port(name, owner), queue(queue)
+    { }
+
+    virtual ~QueuedPort() { }
+
+    /** Check the list of buffered packets against the supplied
+     * functional request. */
+    bool checkFunctional(PacketPtr pkt) { return queue.checkFunctional(pkt); }
+
+    /**
+     * Hook for draining the queued port.
+     *
+     * @param de an event which is used to signal back to the caller
+     * @returns a number indicating how many times process will be called
+     */
+    unsigned int drain(Event *de) { return queue.drain(de); }
+};
+
+#endif // __MEM_QPORT_HH__