ArmVirtualizationPkg: add padding to FDT allocation

Our primary user QEMU/mach-virt presents us with a FDT blob padded
to 64 KB with plenty of room to set additional properties. However,
in the general case, we should only add properties after making sure
there is enough room available.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16960 6f19259b-4bc3-4df7-8a09-765794883524

ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPeiLib.c

@@ -33,6 +33,7 @@ PlatformPeim (
   VOID               *Base;
   VOID               *NewBase;
   UINTN              FdtSize;
+  UINTN              FdtPages;
   UINT64             *FdtHobData;
   UINT64             *UartHobData;
   INT32              Node, Prev;
@@ -47,10 +48,11 @@ PlatformPeim (
   ASSERT (Base != NULL);
   ASSERT (fdt_check_header (Base) == 0);
 
-  FdtSize = fdt_totalsize (Base);
-  NewBase = AllocatePages (EFI_SIZE_TO_PAGES (FdtSize));
+  FdtSize = fdt_totalsize (Base) + PcdGet32 (PcdDeviceTreeAllocationPadding);
+  FdtPages = EFI_SIZE_TO_PAGES (FdtSize);
+  NewBase = AllocatePages (FdtPages);
   ASSERT (NewBase != NULL);
-  CopyMem (NewBase, Base, FdtSize);
+  fdt_open_into (Base, NewBase, EFI_PAGES_TO_SIZE (FdtPages));
 
   FdtHobData = BuildGuidHob (&gFdtHobGuid, sizeof *FdtHobData);
   ASSERT (FdtHobData != NULL);

ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPeiLib.inf

@@ -40,6 +40,7 @@
   gArmTokenSpaceGuid.PcdFvBaseAddress
   gArmTokenSpaceGuid.PcdFvSize
   gArmVirtualizationTokenSpaceGuid.PcdDeviceTreeInitialBaseAddress
+  gArmVirtualizationTokenSpaceGuid.PcdDeviceTreeAllocationPadding
 
 [Guids]
   gEarlyPL011BaseAddressGuid