summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/acpica/hwacpi.c
blob: 96f55f0799881cb221724c3a73fb94f490fd8bf6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
 *
 * Copyright (C) 2000 - 2021, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwacpi")

#if (!ACPI_REDUCED_HARDWARE)	/* Entire module */
/******************************************************************************
 *
 * FUNCTION:    acpi_hw_set_mode
 *
 * PARAMETERS:  mode            - SYS_MODE_ACPI or SYS_MODE_LEGACY
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Transitions the system into the requested mode.
 *
 ******************************************************************************/
acpi_status acpi_hw_set_mode(u32 mode)
{

	acpi_status status;

	ACPI_FUNCTION_TRACE(hw_set_mode);

	/* If the Hardware Reduced flag is set, machine is always in acpi mode */

	if (acpi_gbl_reduced_hardware) {
		return_ACPI_STATUS(AE_OK);
	}

	/*
	 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
	 * system does not support mode transition.
	 */
	if (!acpi_gbl_FADT.smi_command) {
		ACPI_ERROR((AE_INFO,
			    "No SMI_CMD in FADT, mode transition failed"));
		return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
	}

	/*
	 * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
	 * in FADT: If it is zero, enabling or disabling is not supported.
	 * As old systems may have used zero for mode transition,
	 * we make sure both the numbers are zero to determine these
	 * transitions are not supported.
	 */
	if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
		ACPI_ERROR((AE_INFO,
			    "No ACPI mode transition supported in this system "
			    "(enable/disable both zero)"));
		return_ACPI_STATUS(AE_OK);
	}

	switch (mode) {
	case ACPI_SYS_MODE_ACPI:

		/* BIOS should have disabled ALL fixed and GP events */

		status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
					    (u32) acpi_gbl_FADT.acpi_enable, 8);
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Attempting to enable ACPI mode\n"));
		break;

	case ACPI_SYS_MODE_LEGACY:
		/*
		 * BIOS should clear all fixed status bits and restore fixed event
		 * enable bits to default
		 */
		status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
					    (u32)acpi_gbl_FADT.acpi_disable, 8);
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Attempting to enable Legacy (non-ACPI) mode\n"));
		break;

	default:

		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status,
				"Could not write ACPI mode change"));
		return_ACPI_STATUS(status);
	}

	return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_get_mode
 *
 * PARAMETERS:  none
 *
 * RETURN:      SYS_MODE_ACPI or SYS_MODE_LEGACY
 *
 * DESCRIPTION: Return current operating state of system. Determined by
 *              querying the SCI_EN bit.
 *
 ******************************************************************************/

u32 acpi_hw_get_mode(void)
{
	acpi_status status;
	u32 value;

	ACPI_FUNCTION_TRACE(hw_get_mode);

	/* If the Hardware Reduced flag is set, machine is always in acpi mode */

	if (acpi_gbl_reduced_hardware) {
		return_UINT32(ACPI_SYS_MODE_ACPI);
	}

	/*
	 * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
	 * system does not support mode transition.
	 */
	if (!acpi_gbl_FADT.smi_command) {
		return_UINT32(ACPI_SYS_MODE_ACPI);
	}

	status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
	if (ACPI_FAILURE(status)) {
		return_UINT32(ACPI_SYS_MODE_LEGACY);
	}

	if (value) {
		return_UINT32(ACPI_SYS_MODE_ACPI);
	} else {
		return_UINT32(ACPI_SYS_MODE_LEGACY);
	}
}

#endif				/* !ACPI_REDUCED_HARDWARE */