OvmfPkg/Library/PlatformInitLib/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 <Library/PlatformInitLib.h>
  10 #include <Library/DebugLib.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 PlatformCmosRead8 (
  27   IN      UINTN  Index
  28   )
  29 {
  30   IoWrite8 (0x70, (UINT8)Index);
  31   return IoRead8 (0x71);
  32 }
  33
  34 /**
  35   Writes 8-bits of CMOS data.
  36
  37   Writes 8-bits of CMOS data to the location specified by Index
  38   with the value specified by Value and returns Value.
  39
  40   @param  Index  The CMOS location to write.
  41   @param  Value  The value to write to CMOS.
  42
  43   @return The value written to CMOS.
  44
  45 **/
  46 UINT8
  47 EFIAPI
  48 PlatformCmosWrite8 (
  49   IN      UINTN  Index,
  50   IN      UINT8  Value
  51   )
  52 {
  53   IoWrite8 (0x70, (UINT8)Index);
  54   IoWrite8 (0x71, Value);
  55   return Value;
  56 }
  57
  58 /**
  59    Dump the CMOS content
  60  */
  61 VOID
  62 EFIAPI
  63 PlatformDebugDumpCmos (
  64   VOID
  65   )
  66 {
  67   UINT32  Loop;
  68
  69   DEBUG ((DEBUG_INFO, "CMOS:\n"));
  70
  71   for (Loop = 0; Loop < 0x80; Loop++) {
  72     if ((Loop % 0x10) == 0) {
  73       DEBUG ((DEBUG_INFO, "%02x:", Loop));
  74     }
  75
  76     DEBUG ((DEBUG_INFO, " %02x", PlatformCmosRead8 (Loop)));
  77     if ((Loop % 0x10) == 0xf) {
  78       DEBUG ((DEBUG_INFO, "\n"));
  79     }
  80   }
  81 }