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diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyCmos.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyCmos.c
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+/** @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>
+
+This program and the accompanying materials
+are licensed and made available under the terms and conditions
+of the BSD License which accompanies this distribution. The
+full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#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;
+}