1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2023 Linaro Limited
4 * Copyright 2023 Intel Corporation
5 *
6 * Library routines for retrieving trip point temperature values from the
7 * platform firmware via ACPI.
8 */
9#include <linux/acpi.h>
10#include <linux/units.h>
11#include <linux/thermal.h>
12#include "internal.h"
13
14/*
15 * Minimum temperature for full military grade is 218°K (-55°C) and
16 * max temperature is 448°K (175°C). We can consider those values as
17 * the boundaries for the [trips] temperature returned by the
18 * firmware. Any values out of these boundaries may be considered
19 * bogus and we can assume the firmware has no data to provide.
20 */
21#define TEMP_MIN_DECIK 2180ULL
22#define TEMP_MAX_DECIK 4480ULL
23
24static int acpi_trip_temp(struct acpi_device *adev, char *obj_name,
25 int *ret_temp)
26{
27 unsigned long long temp;
28 acpi_status status;
29
30 status = acpi_evaluate_integer(handle: adev->handle, pathname: obj_name, NULL, data: &temp);
31 if (ACPI_FAILURE(status)) {
32 acpi_handle_debug(adev->handle, "%s evaluation failed\n", obj_name);
33 return -ENODATA;
34 }
35
36 if (temp >= TEMP_MIN_DECIK && temp <= TEMP_MAX_DECIK) {
37 *ret_temp = temp;
38 } else {
39 acpi_handle_debug(adev->handle, "%s result %llu out of range\n",
40 obj_name, temp);
41 *ret_temp = THERMAL_TEMP_INVALID;
42 }
43
44 return 0;
45}
46
47int acpi_active_trip_temp(struct acpi_device *adev, int id, int *ret_temp)
48{
49 char obj_name[] = {'_', 'A', 'C', '0' + id, '\0'};
50
51 if (id < 0 || id > 9)
52 return -EINVAL;
53
54 return acpi_trip_temp(adev, obj_name, ret_temp);
55}
56EXPORT_SYMBOL_NS_GPL(acpi_active_trip_temp, "ACPI_THERMAL");
57
58int acpi_passive_trip_temp(struct acpi_device *adev, int *ret_temp)
59{
60 return acpi_trip_temp(adev, obj_name: "_PSV", ret_temp);
61}
62EXPORT_SYMBOL_NS_GPL(acpi_passive_trip_temp, "ACPI_THERMAL");
63
64int acpi_hot_trip_temp(struct acpi_device *adev, int *ret_temp)
65{
66 return acpi_trip_temp(adev, obj_name: "_HOT", ret_temp);
67}
68EXPORT_SYMBOL_NS_GPL(acpi_hot_trip_temp, "ACPI_THERMAL");
69
70int acpi_critical_trip_temp(struct acpi_device *adev, int *ret_temp)
71{
72 return acpi_trip_temp(adev, obj_name: "_CRT", ret_temp);
73}
74EXPORT_SYMBOL_NS_GPL(acpi_critical_trip_temp, "ACPI_THERMAL");
75
76static int thermal_temp(int error, int temp_decik, int *ret_temp)
77{
78 if (error)
79 return error;
80
81 if (temp_decik == THERMAL_TEMP_INVALID)
82 *ret_temp = THERMAL_TEMP_INVALID;
83 else
84 *ret_temp = deci_kelvin_to_millicelsius(t: temp_decik);
85
86 return 0;
87}
88
89/**
90 * thermal_acpi_active_trip_temp - Retrieve active trip point temperature
91 * @adev: Target thermal zone ACPI device object.
92 * @id: Active cooling level (0 - 9).
93 * @ret_temp: Address to store the retrieved temperature value on success.
94 *
95 * Evaluate the _ACx object for the thermal zone represented by @adev to obtain
96 * the temperature of the active cooling trip point corresponding to the active
97 * cooling level given by @id.
98 *
99 * Return 0 on success or a negative error value on failure.
100 */
101int thermal_acpi_active_trip_temp(struct acpi_device *adev, int id, int *ret_temp)
102{
103 int temp_decik = 0;
104 int ret = acpi_active_trip_temp(adev, id, &temp_decik);
105
106 return thermal_temp(error: ret, temp_decik, ret_temp);
107}
108EXPORT_SYMBOL_GPL(thermal_acpi_active_trip_temp);
109
110/**
111 * thermal_acpi_passive_trip_temp - Retrieve passive trip point temperature
112 * @adev: Target thermal zone ACPI device object.
113 * @ret_temp: Address to store the retrieved temperature value on success.
114 *
115 * Evaluate the _PSV object for the thermal zone represented by @adev to obtain
116 * the temperature of the passive cooling trip point.
117 *
118 * Return 0 on success or -ENODATA on failure.
119 */
120int thermal_acpi_passive_trip_temp(struct acpi_device *adev, int *ret_temp)
121{
122 int temp_decik = 0;
123 int ret = acpi_passive_trip_temp(adev, &temp_decik);
124
125 return thermal_temp(error: ret, temp_decik, ret_temp);
126}
127EXPORT_SYMBOL_GPL(thermal_acpi_passive_trip_temp);
128
129/**
130 * thermal_acpi_hot_trip_temp - Retrieve hot trip point temperature
131 * @adev: Target thermal zone ACPI device object.
132 * @ret_temp: Address to store the retrieved temperature value on success.
133 *
134 * Evaluate the _HOT object for the thermal zone represented by @adev to obtain
135 * the temperature of the trip point at which the system is expected to be put
136 * into the S4 sleep state.
137 *
138 * Return 0 on success or -ENODATA on failure.
139 */
140int thermal_acpi_hot_trip_temp(struct acpi_device *adev, int *ret_temp)
141{
142 int temp_decik = 0;
143 int ret = acpi_hot_trip_temp(adev, &temp_decik);
144
145 return thermal_temp(error: ret, temp_decik, ret_temp);
146}
147EXPORT_SYMBOL_GPL(thermal_acpi_hot_trip_temp);
148
149/**
150 * thermal_acpi_critical_trip_temp - Retrieve critical trip point temperature
151 * @adev: Target thermal zone ACPI device object.
152 * @ret_temp: Address to store the retrieved temperature value on success.
153 *
154 * Evaluate the _CRT object for the thermal zone represented by @adev to obtain
155 * the temperature of the critical cooling trip point.
156 *
157 * Return 0 on success or -ENODATA on failure.
158 */
159int thermal_acpi_critical_trip_temp(struct acpi_device *adev, int *ret_temp)
160{
161 int temp_decik = 0;
162 int ret = acpi_critical_trip_temp(adev, &temp_decik);
163
164 return thermal_temp(error: ret, temp_decik, ret_temp);
165}
166EXPORT_SYMBOL_GPL(thermal_acpi_critical_trip_temp);
167