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, 22 insertions, 0 deletions

diff --git a/src/dev/serial.cc b/src/dev/serial.cc
index 63e8a382b..68fc94c57 100644
--- a/src/dev/serial.cc
+++ b/src/dev/serial.cc
@@ -41,6 +41,7 @@
 
 #include "base/misc.hh"
 #include "params/SerialDevice.hh"
+#include "params/SerialNullDevice.hh"
 
 SerialDevice::SerialDevice(const SerialDeviceParams *p)
     : SimObject(p), interfaceCallback(nullptr)
@@ -71,3 +72,24 @@ SerialDevice::notifyInterface()
         interfaceCallback->process();
 }
 
+
+
+
+SerialNullDevice::SerialNullDevice(const SerialNullDeviceParams *p)
+    : SerialDevice(p)
+{
+}
+
+uint8_t
+SerialNullDevice::readData()
+{
+    panic("SerialNullDevice does not have pending data.\n");
+}
+
+
+
+SerialNullDevice *
+SerialNullDeviceParams::create()
+{
+    return new SerialNullDevice(this);
+}