OvmfPkg/PlatformPei/Cmos.c

/** @file
  PC/AT CMOS access routines

  Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
  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 "Cmos.h"
#include "Library/IoLib.h"

/**
  Reads 8-bits of CMOS data.

  Reads the 8-bits of CMOS data at the location specified by Index.
  The 8-bit read value is returned.

  @param  Index  The CMOS location to read.

  @return The value read.

**/
UINT8
EFIAPI
CmosRead8 (
  IN      UINTN                     Index
  )
{
  IoWrite8 (0x70, (UINT8) Index);
  return IoRead8 (0x71);
}


/**
  Writes 8-bits of CMOS data.

  Writes 8-bits of CMOS data to the location specified by Index
  with the value specified by Value and returns Value.

  @param  Index  The CMOS location to write.
  @param  Value  The value to write to CMOS.

  @return The value written to CMOS.

**/
UINT8
EFIAPI
CmosWrite8 (
  IN      UINTN                     Index,
  IN      UINT8                     Value
  )
{
  IoWrite8 (0x70, (UINT8) Index);
  IoWrite8 (0x71, Value);
  return Value;
}