OvmfPkg/PlatformPei/Cmos.c

   1 /** @file
   2   PC/AT CMOS access routines
   3
   4   Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9
  10 #include "Cmos.h"
  11 #include "Library/IoLib.h"
  12
  13 /**
  14   Reads 8-bits of CMOS data.
  15
  16   Reads the 8-bits of CMOS data at the location specified by Index.
  17   The 8-bit read value is returned.
  18
  19   @param  Index  The CMOS location to read.
  20
  21   @return The value read.
  22
  23 **/
  24 UINT8
  25 EFIAPI
  26 CmosRead8 (
  27   IN      UINTN                     Index
  28   )
  29 {
  30   IoWrite8 (0x70, (UINT8) Index);
  31   return IoRead8 (0x71);
  32 }
  33
  34
  35 /**
  36   Writes 8-bits of CMOS data.
  37
  38   Writes 8-bits of CMOS data to the location specified by Index
  39   with the value specified by Value and returns Value.
  40
  41   @param  Index  The CMOS location to write.
  42   @param  Value  The value to write to CMOS.
  43
  44   @return The value written to CMOS.
  45
  46 **/
  47 UINT8
  48 EFIAPI
  49 CmosWrite8 (
  50   IN      UINTN                     Index,
  51   IN      UINT8                     Value
  52   )
  53 {
  54   IoWrite8 (0x70, (UINT8) Index);
  55   IoWrite8 (0x71, Value);
  56   return Value;
  57 }
  58