EmbeddedPkg: Clarify the declaration of SerialPortGetControl()

[mirror_edk2.git] / ArmPlatformPkg / Library / PL011SerialPortLib / PL011SerialPortExtLib.c

diff --git a/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortExtLib.c b/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortExtLib.c
index 7b3cd89298d8e6ddfee1b353d0ee464e90bb4d52..44fe78f4f46b1933fc1a88f8e8d14cee246a07c0 100644 (file)
--- a/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortExtLib.c
+++ b/ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortExtLib.c
@@ -100,20 +100,38 @@ SerialPortSetControl (
 }\r
 \r
 /**\r
-  Get the serial device control bits.\r
 \r
-  @param  Control                 Control signals read from the serial device.\r
-\r
-  @retval EFI_SUCCESS             The control bits were read from the serial device.\r
-  @retval EFI_DEVICE_ERROR        The serial device is not functioning correctly.\r
+  Retrieve the status of the control bits on a serial device.\r
+\r
+  @param[out]  Control  Status of the control bits on a serial device :\r
+\r
+                        . EFI_SERIAL_DATA_CLEAR_TO_SEND, EFI_SERIAL_DATA_SET_READY,\r
+                          EFI_SERIAL_RING_INDICATE, EFI_SERIAL_CARRIER_DETECT,\r
+                          EFI_SERIAL_REQUEST_TO_SEND, EFI_SERIAL_DATA_TERMINAL_READY\r
+                          are all related to the DTE (Data Terminal Equipment) and\r
+                          DCE (Data Communication Equipment) modes of operation of\r
+                          the serial device.\r
+                        . EFI_SERIAL_INPUT_BUFFER_EMPTY : equal to one if the receive\r
+                          buffer is empty, 0 otherwise.\r
+                        . EFI_SERIAL_OUTPUT_BUFFER_EMPTY : equal to one if the transmit\r
+                          buffer is empty, 0 otherwise.\r
+                        . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : equal to one if the\r
+                          hardware loopback is enabled (the ouput feeds the receive\r
+                          buffer), 0 otherwise.\r
+                        . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : equal to one if a\r
+                          loopback is accomplished by software, 0 otherwise.\r
+                        . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : equal to one if the\r
+                          hardware flow control based on CTS (Clear To Send) and RTS\r
+                          (Ready To Send) control signals is enabled, 0 otherwise.\r
+\r
+  @retval RETURN_SUCCESS  The control bits were read from the serial device.\r
 \r
 **/\r
 RETURN_STATUS\r
 EFIAPI\r
 SerialPortGetControl (\r
-  OUT UINT32                  *Control\r
+  OUT UINT32  *Control\r
   )\r
 {\r
   return PL011UartGetControl ((UINTN)PcdGet64 (PcdSerialRegisterBase), Control);\r
 }\r
-\r