1 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
2 | /****************************************************************************** |
3 | * |
4 | * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface |
5 | * |
6 | * Copyright (C) 2000 - 2023, Intel Corp. |
7 | * |
8 | *****************************************************************************/ |
9 | |
10 | #include <acpi/acpi.h> |
11 | #include "accommon.h" |
12 | |
13 | #define _COMPONENT ACPI_HARDWARE |
14 | ACPI_MODULE_NAME("hwacpi" ) |
15 | |
16 | #if (!ACPI_REDUCED_HARDWARE) /* Entire module */ |
17 | /****************************************************************************** |
18 | * |
19 | * FUNCTION: acpi_hw_set_mode |
20 | * |
21 | * PARAMETERS: mode - SYS_MODE_ACPI or SYS_MODE_LEGACY |
22 | * |
23 | * RETURN: Status |
24 | * |
25 | * DESCRIPTION: Transitions the system into the requested mode. |
26 | * |
27 | ******************************************************************************/ |
28 | acpi_status acpi_hw_set_mode(u32 mode) |
29 | { |
30 | |
31 | acpi_status status; |
32 | |
33 | ACPI_FUNCTION_TRACE(hw_set_mode); |
34 | |
35 | /* If the Hardware Reduced flag is set, machine is always in acpi mode */ |
36 | |
37 | if (acpi_gbl_reduced_hardware) { |
38 | return_ACPI_STATUS(AE_OK); |
39 | } |
40 | |
41 | /* |
42 | * ACPI 2.0 clarified that if SMI_CMD in FADT is zero, |
43 | * system does not support mode transition. |
44 | */ |
45 | if (!acpi_gbl_FADT.smi_command) { |
46 | ACPI_ERROR((AE_INFO, |
47 | "No SMI_CMD in FADT, mode transition failed" )); |
48 | return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE); |
49 | } |
50 | |
51 | /* |
52 | * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE |
53 | * in FADT: If it is zero, enabling or disabling is not supported. |
54 | * As old systems may have used zero for mode transition, |
55 | * we make sure both the numbers are zero to determine these |
56 | * transitions are not supported. |
57 | */ |
58 | if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) { |
59 | ACPI_ERROR((AE_INFO, |
60 | "No ACPI mode transition supported in this system " |
61 | "(enable/disable both zero)" )); |
62 | return_ACPI_STATUS(AE_OK); |
63 | } |
64 | |
65 | switch (mode) { |
66 | case ACPI_SYS_MODE_ACPI: |
67 | |
68 | /* BIOS should have disabled ALL fixed and GP events */ |
69 | |
70 | status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, |
71 | (u32) acpi_gbl_FADT.acpi_enable, 8); |
72 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, |
73 | "Attempting to enable ACPI mode\n" )); |
74 | break; |
75 | |
76 | case ACPI_SYS_MODE_LEGACY: |
77 | /* |
78 | * BIOS should clear all fixed status bits and restore fixed event |
79 | * enable bits to default |
80 | */ |
81 | status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, |
82 | (u32)acpi_gbl_FADT.acpi_disable, 8); |
83 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, |
84 | "Attempting to enable Legacy (non-ACPI) mode\n" )); |
85 | break; |
86 | |
87 | default: |
88 | |
89 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
90 | } |
91 | |
92 | if (ACPI_FAILURE(status)) { |
93 | ACPI_EXCEPTION((AE_INFO, status, |
94 | "Could not write ACPI mode change" )); |
95 | return_ACPI_STATUS(status); |
96 | } |
97 | |
98 | return_ACPI_STATUS(AE_OK); |
99 | } |
100 | |
101 | /******************************************************************************* |
102 | * |
103 | * FUNCTION: acpi_hw_get_mode |
104 | * |
105 | * PARAMETERS: none |
106 | * |
107 | * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY |
108 | * |
109 | * DESCRIPTION: Return current operating state of system. Determined by |
110 | * querying the SCI_EN bit. |
111 | * |
112 | ******************************************************************************/ |
113 | |
114 | u32 acpi_hw_get_mode(void) |
115 | { |
116 | acpi_status status; |
117 | u32 value; |
118 | |
119 | ACPI_FUNCTION_TRACE(hw_get_mode); |
120 | |
121 | /* If the Hardware Reduced flag is set, machine is always in acpi mode */ |
122 | |
123 | if (acpi_gbl_reduced_hardware) { |
124 | return_UINT32(ACPI_SYS_MODE_ACPI); |
125 | } |
126 | |
127 | /* |
128 | * ACPI 2.0 clarified that if SMI_CMD in FADT is zero, |
129 | * system does not support mode transition. |
130 | */ |
131 | if (!acpi_gbl_FADT.smi_command) { |
132 | return_UINT32(ACPI_SYS_MODE_ACPI); |
133 | } |
134 | |
135 | status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value); |
136 | if (ACPI_FAILURE(status)) { |
137 | return_UINT32(ACPI_SYS_MODE_LEGACY); |
138 | } |
139 | |
140 | if (value) { |
141 | return_UINT32(ACPI_SYS_MODE_ACPI); |
142 | } else { |
143 | return_UINT32(ACPI_SYS_MODE_LEGACY); |
144 | } |
145 | } |
146 | |
147 | #endif /* !ACPI_REDUCED_HARDWARE */ |
148 | |