ArmPlatformPkg/PL011SerialPortLib: Add hardware flow control support

This change introduces hardware flow control capabilities for the
PL011 serial port Library.

Signed-off-by: Xin Xie <[email protected]>

Author: Xin Xie

ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.c

@@ -57,6 +57,16 @@ SerialPortInitialize (
     return Status;
   }
 
+  if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
+    Status = PL011UartSetControl (
+               (UINTN)PcdGet64 (PcdSerialRegisterBase),
+               EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE
+               );
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
   while (SerialPortPoll ()) {
     SerialPortRead (&Scratch, sizeof (Scratch));
   }

ArmPlatformPkg/Library/PL011SerialPortLib/PL011SerialPortLib.inf

@@ -32,6 +32,7 @@
 
 [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterBase
+  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseHardwareFlowControl
 
 [Pcd]
   gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate