fastmodel: Add a utility class which makes it easier to watch signals.

These signals come from the exported virtual subsystem and could signal
interrupts, etc. The new SignalReceiver class makes it easier to watch
those signals and perform some behavior when they change without having
to bring along a lot of systemc baggage.

Change-Id: I09651de1dd0e7340a61779aaf080c695ce299fd4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21043
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/src/arch/arm/fastmodel/common/signal_receiver.hh b/src/arch/arm/fastmodel/common/signal_receiver.hh
new file mode 100644 (file)
index 0000000..c249c3a
--- /dev/null
+++ b/src/arch/arm/fastmodel/common/signal_receiver.hh
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2019 Google, Inc.
+ *
+ * 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: Gabe Black
+ */
+
+#ifndef __ARCH_ARM_FASTMODEL_COMMON_SIGNAL_RECEIVER_HH__
+#define __ARCH_ARM_FASTMODEL_COMMON_SIGNAL_RECEIVER_HH__
+
+#include <amba_pv.h>
+#include <functional>
+
+namespace FastModel
+{
+
+class SignalReceiver : public amba_pv::signal_slave_base<bool>
+{
+  public:
+    typedef std::function<void(bool)> OnChangeFunc;
+
+  private:
+    bool _state;
+    OnChangeFunc _onChange;
+
+  public:
+    amba_pv::signal_slave_export<bool> signal_in;
+
+    SignalReceiver(const char *name) : SignalReceiver(name, nullptr) {}
+
+    SignalReceiver(const char *name, OnChangeFunc on_change) :
+        amba_pv::signal_slave_base<bool>(name),
+        _state(false), _onChange(on_change)
+    {
+        signal_in.bind(*this);
+    }
+
+    void onChange(OnChangeFunc func) { _onChange = func; }
+
+    void
+    set_state(int export_id, const bool &new_state) override
+    {
+        if (new_state == _state)
+            return;
+
+        _state = new_state;
+        _onChange(_state);
+    }
+};
+
+} // namespace FastModel
+
+#endif // __ARCH_ARM_FASTMODEL_COMMON_SIGNAL_RECEIVER_HH__