dev: Add a dummy serial device

Add a dummy serial device that discards any output and doesn't provide
any input. This device can be used to terminate UARTs that don't have
a default device (e.g., a terminal) attached.

Change-Id: I4a6b0b5037ce360f59bfb5c566e1698d113a1d26
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4290
Reviewed-by: Gabe Black <gabeblack@google.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/dev/serial.hh b/src/dev/serial.hh
index 4ea2f5ea8..230ecaa74 100644
--- a/src/dev/serial.hh
+++ b/src/dev/serial.hh
@@ -44,6 +44,7 @@
 #include "sim/sim_object.hh"
 
 struct SerialDeviceParams;
+struct SerialNullDeviceParams;
 
 /**
  * Base class for serial devices such as terminals.
@@ -140,4 +141,18 @@ class SerialDevice : public SimObject
     Callback *interfaceCallback;
 };
 
+/**
+ * Dummy serial device that discards all data sent to it.
+ */
+class SerialNullDevice : public SerialDevice
+{
+  public:
+    SerialNullDevice(const SerialNullDeviceParams *p);
+
+  public:
+    bool dataAvailable() const override { return false; }
+    void writeData(uint8_t c) override {};
+    uint8_t readData() override;
+};
+
 #endif // __DEV_SERIAL_HH__