systemc: Provide Port wrapper classes for sc_port

Add Port wrappers for sc_port, sc_interface, and sc_export.

Change-Id: Ib70cb7466461c8d32e3a260bf2a2d60a6ded87c3
Signed-off-by: Chun-Chen TK Hsu <chunchenhsu@google.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19788
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/systemc/sc_port_wrapper.hh b/src/systemc/sc_port_wrapper.hh
new file mode 100644
index 0000000..b6f6f85
--- /dev/null
+++ b/src/systemc/sc_port_wrapper.hh
@@ -0,0 +1,171 @@
+/*
+ * Copyright 2019 Google LLC.
+ *
+ * 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: Chun-Chen TK Hsu
+ */
+
+#ifndef __SYSTEMC_SC_PORT_WRAPPER_HH__
+#define __SYSTEMC_SC_PORT_WRAPPER_HH__
+
+#include <string>
+#include <type_traits>
+
+#include "base/logging.hh"
+#include "sim/port.hh"
+#include "systemc/ext/core/sc_export.hh"
+#include "systemc/ext/core/sc_interface.hh"
+#include "systemc/ext/core/sc_port.hh"
+
+namespace sc_gem5
+{
+
+// Forward declaration
+template <typename IF>
+class ScPortWrapper;
+template <typename IF>
+class ScInterfaceWrapper;
+template <typename IF>
+class ScExportWrapper;
+
+template <typename IF>
+class ScPortWrapper : public ::Port
+{
+  public:
+    using ScPort = sc_core::sc_port_b<IF>;
+
+    ScPortWrapper(ScPort& p, const std::string& name, PortID id)
+        : Port(name, id), port_(p)
+    {}
+
+    ScPort&
+    port()
+    {
+        return port_;
+    }
+
+    void
+    unbind() override
+    {
+        panic("sc_port can't be unbound.");
+    }
+
+    void
+    bind(::Port& peer) override
+    {
+        // Try ScPortWrapper or ScInterfaceWrapper
+        if (auto* beer = dynamic_cast<ScPortWrapper<IF>*>(&peer)) {
+            port_.bind(beer->port());
+        } else if (auto* iface =
+                       dynamic_cast<ScInterfaceWrapper<IF>*>(&peer)) {
+            port_.bind(iface->interface());
+        } else {
+            fatal("Attempt to bind sc_port %s to incompatible port %s.",
+                  name(), peer.name());
+        }
+    }
+
+  private:
+    ScPort& port_;
+};
+
+template <typename IF>
+class ScInterfaceWrapper : public ::Port
+{
+  public:
+    ScInterfaceWrapper(IF& i, const std::string name, PortID id)
+        : Port(name, id), iface_(i)
+    {}
+
+    IF&
+    interface()
+    {
+        return iface_;
+    }
+
+    void
+    unbind() override
+    {
+        panic("sc_interface can't be unbound.");
+    }
+
+    void
+    bind(::Port& peer) override
+    {
+        // fatal error if peer is neither ScPortWrapper nor ScExportWrapper
+        fatal_if(!dynamic_cast<ScPortWrapper<IF>*>(&peer) &&
+                     !dynamic_cast<ScExportWrapper<IF>*>(&peer),
+                 "Attempt to bind sc_interface %s to incompatible port %s.",
+                 name(), peer.name());
+
+        // Don't bind to peer otherwise we may have error messages saying that
+        // this interface has already be bound since the peer may already did
+        // that. Just let sc_port or sc_export do the binding
+    }
+
+  private:
+    IF& iface_;
+};
+
+template <typename IF>
+class ScExportWrapper : public ::Port
+{
+  public:
+    using ScExport = sc_core::sc_export<IF>;
+
+    ScExportWrapper(ScExport& p, const std::string& name, PortID id)
+        : Port(name, id), port_(p)
+    {}
+
+    ScExport&
+    port()
+    {
+        return port_;
+    }
+
+    void
+    unbind() override
+    {
+        panic("sc_export cannot be unbound.");
+    }
+
+    void
+    bind(::Port& peer) override
+    {
+        auto* iface = dynamic_cast<ScInterfaceWrapper<IF>*>(&peer);
+        fatal_if(!iface,
+                 "Attempt to bind sc_export %s to incompatible port %s.",
+                 name(), peer.name());
+
+        port_.bind(iface->interface());
+    }
+
+  private:
+    ScExport& port_;
+};
+
+}  // namespace sc_gem5
+
+#endif  // __SYSTEMC_SC_PORT_WRAPPER_HH__