audk/OvmfPkg/XenPlatformPei/Cmos.c

58 lines
1.1 KiB
C

/** @file
PC/AT CMOS access routines
Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2019, Citrix Systems, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#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;
}