OvmfPkg/Bhyve/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 #include "Cmos.h"
  10 #include "Library/IoLib.h"
  11
  12 /**
  13   Reads 8-bits of CMOS data.
  14
  15   Reads the 8-bits of CMOS data at the location specified by Index.
  16   The 8-bit read value is returned.
  17
  18   @param  Index  The CMOS location to read.
  19
  20   @return The value read.
  21
  22 **/
  23 UINT8
  24 EFIAPI
  25 CmosRead8 (
  26   IN      UINTN  Index
  27   )
  28 {
  29   IoWrite8 (0x70, (UINT8)Index);
  30   return IoRead8 (0x71);
  31 }
  32
  33 /**
  34   Writes 8-bits of CMOS data.
  35
  36   Writes 8-bits of CMOS data to the location specified by Index
  37   with the value specified by Value and returns Value.
  38
  39   @param  Index  The CMOS location to write.
  40   @param  Value  The value to write to CMOS.
  41
  42   @return The value written to CMOS.
  43
  44 **/
  45 UINT8
  46 EFIAPI
  47 CmosWrite8 (
  48   IN      UINTN  Index,
  49   IN      UINT8  Value
  50   )
  51 {
  52   IoWrite8 (0x70, (UINT8)Index);
  53   IoWrite8 (0x71, Value);
  54   return Value;
  55 }