/** @file | |
This code fills in standard CMOS values and updates the standard CMOS | |
checksum. The Legacy16 code or LegacyBiosPlatform.c is responsible for | |
non-standard CMOS locations and non-standard checksums. | |
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include "LegacyBiosInterface.h" | |
/** | |
Read CMOS register through index/data port. | |
@param[in] Index The index of the CMOS register to read. | |
@return The data value from the CMOS register specified by Index. | |
**/ | |
UINT8 | |
LegacyReadStandardCmos ( | |
IN UINT8 Index | |
) | |
{ | |
IoWrite8 (PORT_70, Index); | |
return IoRead8 (PORT_71); | |
} | |
/** | |
Write CMOS register through index/data port. | |
@param[in] Index The index of the CMOS register to write. | |
@param[in] Value The value of CMOS register to write. | |
@return The value written to the CMOS register specified by Index. | |
**/ | |
UINT8 | |
LegacyWriteStandardCmos ( | |
IN UINT8 Index, | |
IN UINT8 Value | |
) | |
{ | |
IoWrite8 (PORT_70, Index); | |
return IoWrite8 (PORT_71, Value); | |
} | |
/** | |
Calculate the new standard CMOS checksum and write it. | |
@param Private Legacy BIOS Instance data | |
@retval EFI_SUCCESS Calculate 16-bit checksum successfully | |
**/ | |
EFI_STATUS | |
LegacyCalculateWriteStandardCmosChecksum ( | |
VOID | |
) | |
{ | |
UINT8 Register; | |
UINT16 Checksum; | |
for (Checksum = 0, Register = 0x10; Register < 0x2e; Register++) { | |
Checksum = (UINT16)(Checksum + LegacyReadStandardCmos (Register)); | |
} | |
LegacyWriteStandardCmos (CMOS_2E, (UINT8)(Checksum >> 8)); | |
LegacyWriteStandardCmos (CMOS_2F, (UINT8)(Checksum & 0xff)); | |
return EFI_SUCCESS; | |
} | |
/** | |
Fill in the standard CMOS stuff before Legacy16 load | |
@param Private Legacy BIOS Instance data | |
@retval EFI_SUCCESS It should always work. | |
**/ | |
EFI_STATUS | |
LegacyBiosInitCmos ( | |
IN LEGACY_BIOS_INSTANCE *Private | |
) | |
{ | |
UINT32 Size; | |
// | |
// Clear all errors except RTC lost power | |
// | |
LegacyWriteStandardCmos (CMOS_0E, (UINT8)(LegacyReadStandardCmos (CMOS_0E) & BIT7)); | |
// | |
// Update CMOS locations 15,16,17,18,30,31 and 32 | |
// CMOS 16,15 = 640Kb = 0x280 | |
// CMOS 18,17 = 31,30 = 15Mb max in 1Kb increments =0x3C00 max | |
// CMOS 32 = 0x20 | |
// | |
LegacyWriteStandardCmos (CMOS_15, 0x80); | |
LegacyWriteStandardCmos (CMOS_16, 0x02); | |
Size = 15 * SIZE_1MB; | |
if (Private->IntThunk->EfiToLegacy16InitTable.OsMemoryAbove1Mb < (15 * SIZE_1MB)) { | |
Size = Private->IntThunk->EfiToLegacy16InitTable.OsMemoryAbove1Mb >> 10; | |
} | |
LegacyWriteStandardCmos (CMOS_17, (UINT8)(Size & 0xFF)); | |
LegacyWriteStandardCmos (CMOS_30, (UINT8)(Size & 0xFF)); | |
LegacyWriteStandardCmos (CMOS_18, (UINT8)(Size >> 8)); | |
LegacyWriteStandardCmos (CMOS_31, (UINT8)(Size >> 8)); | |
LegacyCalculateWriteStandardCmosChecksum (); | |
return EFI_SUCCESS; | |
} |