source: vbox/trunk/src/VBox/Devices/EFI/FirmwareNew/OvmfPkg/Library/PlatformInitLib/Cmos.c

/** @file
  PC/AT CMOS access routines

  Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/PlatformInitLib.h>
#include <Library/DebugLib.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
PlatformCmosRead8 (
  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
PlatformCmosWrite8 (
  IN      UINTN  Index,
  IN      UINT8  Value
  )
{
  IoWrite8 (0x70, (UINT8)Index);
  IoWrite8 (0x71, Value);
  return Value;
}

/**
   Dump the CMOS content
 */
VOID
EFIAPI
PlatformDebugDumpCmos (
  VOID
  )
{
  UINT32  Loop;

  DEBUG ((DEBUG_INFO, "CMOS:\n"));

  for (Loop = 0; Loop < 0x80; Loop++) {
    if ((Loop % 0x10) == 0) {
      DEBUG ((DEBUG_INFO, "%02x:", Loop));
    }

    DEBUG ((DEBUG_INFO, " %02x", PlatformCmosRead8 (Loop)));
    if ((Loop % 0x10) == 0xf) {
      DEBUG ((DEBUG_INFO, "\n"));
    }
  }
}