audk/ArmPlatformPkg/Library/PrePiHobListPointerLib/PrePiHobListPointer.c

/** @file
*
*  Copyright (c) 2011, ARM Limited. All rights reserved.
*  
*  This program and the accompanying materials                          
*  are licensed and made available under the terms and conditions of the BSD License         
*  which accompanies this distribution.  The full text of the license may be found at        
*  http://opensource.org/licenses/bsd-license.php                                            
*
*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             
*
**/

#include <PiPei.h>
#include <Library/PrePiHobListPointerLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>

//
// Have to use build system to set the original value in case we are running
// from FLASH and globals don't work. So if you do a GetHobList() and gHobList
// and gHobList is NULL the PCD default values are used.
//
VOID *gHobList = NULL;


/**
  Returns the pointer to the HOB list.

  This function returns the pointer to first HOB in the list.

  @return The pointer to the HOB list.

**/
VOID *
EFIAPI
PrePeiGetHobList (
  VOID
  )
{
  if (gHobList == NULL) {
    return (VOID *)*(UINTN*)(PcdGet32 (PcdCPUCoresNonSecStackBase) + (PcdGet32 (PcdCPUCoresNonSecStackSize) / 2) - PcdGet32 (PcdHobListPtrGlobalOffset));
  } else {
    return gHobList;
  }
}



/**
  Updates the pointer to the HOB list.

  @param  HobList       Hob list pointer to store
  
**/
EFI_STATUS
EFIAPI
PrePeiSetHobList (
  IN  VOID      *HobList
  )
{
  gHobList = HobList;
  
  //
  // If this code is running from ROM this could fail
  //
  return (gHobList == HobList) ? EFI_SUCCESS: EFI_UNSUPPORTED;
}