ArmPlatformPkg: Fix and Implement ArmPlatformGetPrimaryCoreMpId

- Used correct PCD
- Implement the function for AArch64, BeagleBoard, CTA15A7

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14937 6f19259b-4bc3-4df7-8a09-765794883524

BeagleBoardPkg/Library/BeagleBoardLib/BeagleBoardHelper.asm

@@ -20,6 +20,9 @@
 
   EXPORT    ArmPlatformPeiBootAction
   EXPORT    ArmPlatformIsPrimaryCore
+  EXPORT    ArmPlatformGetPrimaryCoreMpId
+
+  IMPORT	ArmReadMpidr
 
   AREA BeagleBoardHelper, CODE, READONLY
 
@@ -37,4 +40,14 @@ ArmPlatformPeiBootAction FUNCTION
   bx    lr
   ENDFUNC
 
+//UINTN
+//ArmPlatformGetPrimaryCoreMpId (
+//  VOID
+//  );
+ArmPlatformGetPrimaryCoreMpId FUNCTION
+  // The BeagleBoard is a uniprocessor platform. The MPIDR of primary core is
+  // always the MPIDR of the calling CPU.
+  b		ArmReadMpidr
+  ENDFUNC
+
   END