1 /** @file
2 This code fills in standard CMOS values and updates the standard CMOS
3 checksum. The Legacy16 code or LegacyBiosPlatform.c is responsible for
4 non-standard CMOS locations and non-standard checksums.
5
6 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
7
8 This program and the accompanying materials
9 are licensed and made available under the terms and conditions
10 of the BSD License which accompanies this distribution. The
11 full text of the license may be found at
12 http://opensource.org/licenses/bsd-license.php
13
14 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
15 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
16
17 **/
18
19 #include "LegacyBiosInterface.h"
20
21 /**
22 Read CMOS register through index/data port.
23
24 @param[in] Index The index of the CMOS register to read.
25
26 @return The data value from the CMOS register specified by Index.
27
28 **/
29 UINT8
LegacyReadStandardCmos(IN UINT8 Index)30 LegacyReadStandardCmos (
31 IN UINT8 Index
32 )
33 {
34 IoWrite8 (PORT_70, Index);
35 return IoRead8 (PORT_71);
36 }
37
38 /**
39 Write CMOS register through index/data port.
40
41 @param[in] Index The index of the CMOS register to write.
42 @param[in] Value The value of CMOS register to write.
43
44 @return The value written to the CMOS register specified by Index.
45
46 **/
47 UINT8
LegacyWriteStandardCmos(IN UINT8 Index,IN UINT8 Value)48 LegacyWriteStandardCmos (
49 IN UINT8 Index,
50 IN UINT8 Value
51 )
52 {
53 IoWrite8 (PORT_70, Index);
54 return IoWrite8 (PORT_71, Value);
55 }
56
57 /**
58 Calculate the new standard CMOS checksum and write it.
59
60 @param Private Legacy BIOS Instance data
61
62 @retval EFI_SUCCESS Calculate 16-bit checksum successfully
63
64 **/
65 EFI_STATUS
LegacyCalculateWriteStandardCmosChecksum(VOID)66 LegacyCalculateWriteStandardCmosChecksum (
67 VOID
68 )
69 {
70 UINT8 Register;
71 UINT16 Checksum;
72
73 for (Checksum = 0, Register = 0x10; Register < 0x2e; Register++) {
74 Checksum = (UINT16)(Checksum + LegacyReadStandardCmos (Register));
75 }
76 LegacyWriteStandardCmos (CMOS_2E, (UINT8)(Checksum >> 8));
77 LegacyWriteStandardCmos (CMOS_2F, (UINT8)(Checksum & 0xff));
78 return EFI_SUCCESS;
79 }
80
81
82 /**
83 Fill in the standard CMOS stuff before Legacy16 load
84
85 @param Private Legacy BIOS Instance data
86
87 @retval EFI_SUCCESS It should always work.
88
89 **/
90 EFI_STATUS
LegacyBiosInitCmos(IN LEGACY_BIOS_INSTANCE * Private)91 LegacyBiosInitCmos (
92 IN LEGACY_BIOS_INSTANCE *Private
93 )
94 {
95 UINT32 Size;
96
97 //
98 // Clear all errors except RTC lost power
99 //
100 LegacyWriteStandardCmos (CMOS_0E, (UINT8)(LegacyReadStandardCmos (CMOS_0E) & BIT7));
101
102 //
103 // Update CMOS locations 15,16,17,18,30,31 and 32
104 // CMOS 16,15 = 640Kb = 0x280
105 // CMOS 18,17 = 31,30 = 15Mb max in 1Kb increments =0x3C00 max
106 // CMOS 32 = 0x20
107 //
108 LegacyWriteStandardCmos (CMOS_15, 0x80);
109 LegacyWriteStandardCmos (CMOS_16, 0x02);
110
111 Size = 15 * SIZE_1MB;
112 if (Private->IntThunk->EfiToLegacy16InitTable.OsMemoryAbove1Mb < (15 * SIZE_1MB)) {
113 Size = Private->IntThunk->EfiToLegacy16InitTable.OsMemoryAbove1Mb >> 10;
114 }
115
116 LegacyWriteStandardCmos (CMOS_17, (UINT8)(Size & 0xFF));
117 LegacyWriteStandardCmos (CMOS_30, (UINT8)(Size & 0xFF));
118 LegacyWriteStandardCmos (CMOS_18, (UINT8)(Size >> 8));
119 LegacyWriteStandardCmos (CMOS_31, (UINT8)(Size >> 8));
120
121 LegacyCalculateWriteStandardCmosChecksum ();
122
123 return EFI_SUCCESS;
124 }
125