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>
diff --git a/src/dev/Serial.py b/src/dev/Serial.py
index bbc792b..7871b48 100644
--- a/src/dev/Serial.py
+++ b/src/dev/Serial.py
@@ -42,3 +42,7 @@
type = 'SerialDevice'
abstract = True
cxx_header = "dev/serial.hh"
+
+class SerialNullDevice(SerialDevice):
+ type = 'SerialNullDevice'
+ cxx_header = "dev/serial.hh"
diff --git a/src/dev/serial.cc b/src/dev/serial.cc
index 63e8a38..68fc94c 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 @@
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);
+}
diff --git a/src/dev/serial.hh b/src/dev/serial.hh
index 4ea2f5e..230ecaa 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 @@
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__