/** @file
This is the driver that locates the MemoryConfigurationData HOB, if it
exists, and saves the data to nvRAM.

Copyright (c) 2013-2015 Intel Corporation.

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 <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/UefiDriverEntryPoint.h>

#include <Guid/MemoryConfigData.h>
#include <Guid/DebugMask.h>

EFI_STATUS
EFIAPI
SaveMemoryConfigEntryPoint (
  IN EFI_HANDLE         ImageHandle,
  IN EFI_SYSTEM_TABLE   *SystemTable
  )
/*++

  Routine Description:
    This is the standard EFI driver point that detects whether there is a
    MemoryConfigurationData HOB and, if so, saves its data to nvRAM.

  Arguments:
    ImageHandle   - Handle for the image of this driver
    SystemTable   - Pointer to the EFI System Table

  Returns:
    EFI_SUCCESS   - if the data is successfully saved or there was no data
    EFI_NOT_FOUND - if the HOB list could not be located.
    EFI_UNLOAD_IMAGE - It is not success

--*/
{
  EFI_STATUS  Status;
  VOID        *HobList;
  EFI_HOB_GUID_TYPE *GuidHob;
  VOID        *HobData;
  VOID        *VariableData;
  UINTN       DataSize;
  UINTN       BufferSize;

  DataSize      = 0;
  VariableData  = NULL;
  GuidHob = NULL;
  HobList = NULL;
  HobData = NULL;
  Status  = EFI_UNSUPPORTED;

  //
  // Get the HOB list.  If it is not present, then ASSERT.
  //
  HobList = GetHobList ();
  ASSERT (HobList != NULL);

  //
  // Search for the Memory Configuration GUID HOB.  If it is not present, then
  // there's nothing we can do. It may not exist on the update path.
  //
  GuidHob = GetNextGuidHob (&gEfiMemoryConfigDataGuid, HobList);
  if (GuidHob != NULL) {
    HobData = GET_GUID_HOB_DATA (GuidHob);
    DataSize = GET_GUID_HOB_DATA_SIZE (GuidHob);
    //
    // Use the HOB to save Memory Configuration Data
    //
    BufferSize = DataSize;
    VariableData = AllocatePool (BufferSize);
    ASSERT (VariableData != NULL);
    Status = gRT->GetVariable (
                    EFI_MEMORY_CONFIG_DATA_NAME,
                    &gEfiMemoryConfigDataGuid,
                    NULL,
                    &BufferSize,
                    VariableData
                    );
    if (Status == EFI_BUFFER_TOO_SMALL) {
      gBS->FreePool (VariableData);
      VariableData = AllocatePool (BufferSize);
      ASSERT (VariableData != NULL);
      Status = gRT->GetVariable (
                      EFI_MEMORY_CONFIG_DATA_NAME,
                      &gEfiMemoryConfigDataGuid,
                      NULL,
                      &BufferSize,
                      VariableData
                      );
    }

    if (EFI_ERROR(Status) || BufferSize != DataSize || CompareMem (HobData, VariableData, DataSize) != 0) {
      Status = gRT->SetVariable (
                      EFI_MEMORY_CONFIG_DATA_NAME,
                      &gEfiMemoryConfigDataGuid,
                      (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS),
                      DataSize,
                      HobData
                      );
      ASSERT((Status == EFI_SUCCESS) || (Status == EFI_OUT_OF_RESOURCES));
    }

    gBS->FreePool (VariableData);
  }

  //
  // This driver does not produce any protocol services, so always unload it.
  //
  return Status;
}