MdeModulePkg/Universal/CapsuleRuntimeDxe/Arm/CapsuleReset.c

   1 /** @file
   2   ARM implementation of architecture specific routines related to
   3   PersistAcrossReset capsules
   4
   5   Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
   6   Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
   7
   8   SPDX-License-Identifier: BSD-2-Clause-Patent
   9
  10 **/
  11
  12 #include "CapsuleService.h"
  13
  14 /**
  15   Whether the platform supports capsules that persist across reset. Note that
  16   some platforms only support such capsules at boot time.
  17
  18   @return TRUE  if a PersistAcrossReset capsule may be passed to UpdateCapsule()
  19                 at this time
  20           FALSE otherwise
  21 **/
  22 BOOLEAN
  23 IsPersistAcrossResetCapsuleSupported (
  24   VOID
  25   )
  26 {
  27   //
  28   // ARM requires the capsule payload to be cleaned to the point of coherency
  29   // (PoC), but only permits doing so using cache maintenance instructions that
  30   // operate on virtual addresses. Since at runtime, we don't know the virtual
  31   // addresses of the data structures that make up the scatter/gather list, we
  32   // cannot perform the maintenance, and all we can do is give up.
  33   //
  34   return FeaturePcdGet (PcdSupportUpdateCapsuleReset) && !EfiAtRuntime ();
  35 }
  36