[PATCH 2/2] ArmVirtQemu: enable runtime debug by build flag

[Heyi Guo <guoheyi@huawei.com>]

Introduce a build flag "RT_DEBUG" to enable runtime debug, so that we
can have a handy method for UEFI runtime services debug.

This build flag only applies to DEBUG build; the reason for not
enabling it for DEBUG build by default is that we are still using
the same UART of OS and it may cause potential conflict.

User needs to specify "-D RT_DEBUG=TRUE"; "-D RT_DEBUG" is not enough
for we use !if $(RT_DEBUG)==TRUE in the code.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Julien Grall <julien.grall@arm.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Heyi Guo <guoheyi@huawei.com>
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
---
 ArmVirtPkg/ArmVirt.dsc.inc | 4 ++++
 ArmVirtPkg/ArmVirtQemu.dsc | 1 +
 2 files changed, 5 insertions(+)

diff --git a/ArmVirtPkg/ArmVirt.dsc.inc b/ArmVirtPkg/ArmVirt.dsc.inc
index d172a08..5ace31b 100644
--- a/ArmVirtPkg/ArmVirt.dsc.inc
+++ b/ArmVirtPkg/ArmVirt.dsc.inc
@@ -240,8 +240,12 @@
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
   CapsuleLib|MdeModulePkg/Library/DxeCapsuleLibNull/DxeCapsuleLibNull.inf
 !if $(TARGET) != RELEASE
+!if $(RT_DEBUG) == TRUE
+  SerialPortLib|ArmVirtPkg/Library/FdtPL011SerialPortLib/FdtPL011SerialPortLibRuntime.inf
+!else
   DebugLib|MdePkg/Library/DxeRuntimeDebugLibSerialPort/DxeRuntimeDebugLibSerialPort.inf
 !endif
+!endif
 
 !if $(SECURE_BOOT_ENABLE) == TRUE
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/RuntimeCryptLib.inf
diff --git a/ArmVirtPkg/ArmVirtQemu.dsc b/ArmVirtPkg/ArmVirtQemu.dsc
index d703317..b279d7d 100644
--- a/ArmVirtPkg/ArmVirtQemu.dsc
+++ b/ArmVirtPkg/ArmVirtQemu.dsc
@@ -37,6 +37,7 @@
   DEFINE SECURE_BOOT_ENABLE      = FALSE
   DEFINE NETWORK_IP6_ENABLE      = FALSE
   DEFINE HTTP_BOOT_ENABLE        = FALSE
+  DEFINE RT_DEBUG                = FALSE
 
 !include ArmVirtPkg/ArmVirt.dsc.inc
 
-- 
1.8.3.1