ArmPlatformPkg: Introduce TransferList Guid Hob for SEC

ArmTransferListHobGuid holds TransferList base address
If there's no valid TransferList found, or if a Guid HOB
is already present Guid HOB is not built, boot progresses
as usual.

https://firmwarehandoff.github.io/firmware_handoff

Signed-off-by: Prachotan Bathi <prachotan.bathi@arm.com>

ArmPlatformPkg/PlatformPei/PlatformPeim.c

@@ -24,6 +24,7 @@
 #include <Library/PeimEntryPoint.h>
 #include <Library/PeiServicesLib.h>
 #include <Library/PcdLib.h>
+#include <Guid/TransferListHob.h>
 
 EFI_STATUS
 EFIAPI
@@ -78,12 +79,28 @@ InitializePlatformPeim (
 {
   EFI_STATUS         Status;
   EFI_BOOT_MODE      BootMode;
+  VOID               *TransferListBase;
+  UINTN              *TransferListHobData;
+  EFI_HOB_GUID_TYPE  *GuidHob;
 
   DEBUG ((DEBUG_LOAD | DEBUG_INFO, "Platform PEIM Loaded\n"));
 
   Status = PeiServicesSetBootMode (ArmPlatformGetBootMode ());
   ASSERT_EFI_ERROR (Status);
 
+  // If TransferList PPI is present and TransferListHobGuid is not present,
+  // then create a TransferListHob with the TransferListBase address.
+  Status = PeiServicesLocatePpi (&gArmTransferListPpiGuid, 0, NULL, &TransferListBase);
+  if (!EFI_ERROR (Status)) {
+    GuidHob = GetFirstGuidHob (&gArmTransferListHobGuid);
+    if ((GuidHob == NULL) && (TransferListBase != NULL)) {
+      TransferListHobData = BuildGuidHob (&gArmTransferListHobGuid, sizeof (*TransferListHobData));
+      ASSERT (TransferListHobData != NULL);
+
+      *TransferListHobData = (UINTN)TransferListBase;
+    }
+  }
+
   PlatformPeim ();
 
   Status = PeiServicesGetBootMode (&BootMode);

ArmPlatformPkg/PlatformPei/PlatformPeim.inf

@@ -43,6 +43,7 @@
 [Ppis]
   gEfiPeiMasterBootModePpiGuid                  # PPI ALWAYS_PRODUCED
   gEfiPeiBootInRecoveryModePpiGuid              # PPI SOMETIMES_PRODUCED
+  gArmTransferListPpiGuid                       # PPI SOMETIMES_CONSUMED
 
 [FixedPcd]
   gArmTokenSpaceGuid.PcdFdBaseAddress
@@ -51,6 +52,9 @@
   gArmTokenSpaceGuid.PcdFvBaseAddress
   gArmTokenSpaceGuid.PcdFvSize
 
+[Guids]
+  gArmTransferListHobGuid
+
 [Depex]
   TRUE