1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * thermal_helpers.c - helper functions to handle thermal devices
4 *
5 * Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
6 *
7 * Highly based on original thermal_core.c
8 * Copyright (C) 2008 Intel Corp
9 * Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
10 * Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/export.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 #include <linux/sysfs.h>
21
22 #include <trace/events/thermal.h>
23
24 #include "thermal_core.h"
25
get_tz_trend(struct thermal_zone_device * tz,int trip)26 int get_tz_trend(struct thermal_zone_device *tz, int trip)
27 {
28 enum thermal_trend trend;
29
30 if (tz->emul_temperature || !tz->ops->get_trend ||
31 tz->ops->get_trend(tz, trip, &trend)) {
32 if (tz->temperature > tz->last_temperature)
33 trend = THERMAL_TREND_RAISING;
34 else if (tz->temperature < tz->last_temperature)
35 trend = THERMAL_TREND_DROPPING;
36 else
37 trend = THERMAL_TREND_STABLE;
38 }
39
40 return trend;
41 }
42
43 struct thermal_instance *
get_thermal_instance(struct thermal_zone_device * tz,struct thermal_cooling_device * cdev,int trip)44 get_thermal_instance(struct thermal_zone_device *tz,
45 struct thermal_cooling_device *cdev, int trip)
46 {
47 struct thermal_instance *pos = NULL;
48 struct thermal_instance *target_instance = NULL;
49
50 mutex_lock(&tz->lock);
51 mutex_lock(&cdev->lock);
52
53 list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
54 if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
55 target_instance = pos;
56 break;
57 }
58 }
59
60 mutex_unlock(&cdev->lock);
61 mutex_unlock(&tz->lock);
62
63 return target_instance;
64 }
65 EXPORT_SYMBOL(get_thermal_instance);
66
__thermal_zone_get_temp(struct thermal_zone_device * tz,int * temp)67 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
68 {
69 int ret = -EINVAL;
70 int count;
71 int crit_temp = INT_MAX;
72 enum thermal_trip_type type;
73
74 lockdep_assert_held(&tz->lock);
75
76 if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
77 return -EINVAL;
78
79 ret = tz->ops->get_temp(tz, temp);
80
81 if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
82 for (count = 0; count < tz->num_trips; count++) {
83 ret = tz->ops->get_trip_type(tz, count, &type);
84 if (!ret && type == THERMAL_TRIP_CRITICAL) {
85 ret = tz->ops->get_trip_temp(tz, count,
86 &crit_temp);
87 break;
88 }
89 }
90
91 /*
92 * Only allow emulating a temperature when the real temperature
93 * is below the critical temperature so that the emulation code
94 * cannot hide critical conditions.
95 */
96 if (!ret && *temp < crit_temp)
97 *temp = tz->emul_temperature;
98 }
99
100 return ret;
101 }
102
103 /**
104 * thermal_zone_get_temp() - returns the temperature of a thermal zone
105 * @tz: a valid pointer to a struct thermal_zone_device
106 * @temp: a valid pointer to where to store the resulting temperature.
107 *
108 * When a valid thermal zone reference is passed, it will fetch its
109 * temperature and fill @temp.
110 *
111 * Return: On success returns 0, an error code otherwise
112 */
thermal_zone_get_temp(struct thermal_zone_device * tz,int * temp)113 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
114 {
115 int ret;
116
117 mutex_lock(&tz->lock);
118
119 if (device_is_registered(&tz->device))
120 ret = __thermal_zone_get_temp(tz, temp);
121 else
122 ret = -ENODEV;
123
124 mutex_unlock(&tz->lock);
125
126 return ret;
127 }
128 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
129
__thermal_zone_set_trips(struct thermal_zone_device * tz)130 void __thermal_zone_set_trips(struct thermal_zone_device *tz)
131 {
132 int low = -INT_MAX;
133 int high = INT_MAX;
134 int trip_temp, hysteresis;
135 int i, ret;
136
137 lockdep_assert_held(&tz->lock);
138
139 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
140 return;
141
142 for (i = 0; i < tz->num_trips; i++) {
143 int trip_low;
144
145 tz->ops->get_trip_temp(tz, i, &trip_temp);
146 tz->ops->get_trip_hyst(tz, i, &hysteresis);
147
148 trip_low = trip_temp - hysteresis;
149
150 if (trip_low < tz->temperature && trip_low > low)
151 low = trip_low;
152
153 if (trip_temp > tz->temperature && trip_temp < high)
154 high = trip_temp;
155 }
156
157 /* No need to change trip points */
158 if (tz->prev_low_trip == low && tz->prev_high_trip == high)
159 return;
160
161 tz->prev_low_trip = low;
162 tz->prev_high_trip = high;
163
164 dev_dbg(&tz->device,
165 "new temperature boundaries: %d < x < %d\n", low, high);
166
167 /*
168 * Set a temperature window. When this window is left the driver
169 * must inform the thermal core via thermal_zone_device_update.
170 */
171 ret = tz->ops->set_trips(tz, low, high);
172 if (ret)
173 dev_err(&tz->device, "Failed to set trips: %d\n", ret);
174 }
175
176 /**
177 * thermal_zone_set_trips - Computes the next trip points for the driver
178 * @tz: a pointer to a thermal zone device structure
179 *
180 * The function computes the next temperature boundaries by browsing
181 * the trip points. The result is the closer low and high trip points
182 * to the current temperature. These values are passed to the backend
183 * driver to let it set its own notification mechanism (usually an
184 * interrupt).
185 *
186 * It does not return a value
187 */
thermal_zone_set_trips(struct thermal_zone_device * tz)188 void thermal_zone_set_trips(struct thermal_zone_device *tz)
189 {
190 mutex_lock(&tz->lock);
191 __thermal_zone_set_trips(tz);
192 mutex_unlock(&tz->lock);
193 }
194
thermal_cdev_set_cur_state(struct thermal_cooling_device * cdev,int target)195 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
196 int target)
197 {
198 if (cdev->ops->set_cur_state(cdev, target))
199 return;
200
201 thermal_notify_cdev_state_update(cdev->id, target);
202 thermal_cooling_device_stats_update(cdev, target);
203 }
204
__thermal_cdev_update(struct thermal_cooling_device * cdev)205 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
206 {
207 struct thermal_instance *instance;
208 unsigned long target = 0;
209
210 /* Make sure cdev enters the deepest cooling state */
211 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
212 dev_dbg(&cdev->device, "zone%d->target=%lu\n",
213 instance->tz->id, instance->target);
214 if (instance->target == THERMAL_NO_TARGET)
215 continue;
216 if (instance->target > target)
217 target = instance->target;
218 }
219
220 thermal_cdev_set_cur_state(cdev, target);
221
222 trace_cdev_update(cdev, target);
223 dev_dbg(&cdev->device, "set to state %lu\n", target);
224 }
225
226 /**
227 * thermal_cdev_update - update cooling device state if needed
228 * @cdev: pointer to struct thermal_cooling_device
229 *
230 * Update the cooling device state if there is a need.
231 */
thermal_cdev_update(struct thermal_cooling_device * cdev)232 void thermal_cdev_update(struct thermal_cooling_device *cdev)
233 {
234 mutex_lock(&cdev->lock);
235 if (!cdev->updated) {
236 __thermal_cdev_update(cdev);
237 cdev->updated = true;
238 }
239 mutex_unlock(&cdev->lock);
240 }
241
242 /**
243 * thermal_zone_get_slope - return the slope attribute of the thermal zone
244 * @tz: thermal zone device with the slope attribute
245 *
246 * Return: If the thermal zone device has a slope attribute, return it, else
247 * return 1.
248 */
thermal_zone_get_slope(struct thermal_zone_device * tz)249 int thermal_zone_get_slope(struct thermal_zone_device *tz)
250 {
251 if (tz && tz->tzp)
252 return tz->tzp->slope;
253 return 1;
254 }
255 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
256
257 /**
258 * thermal_zone_get_offset - return the offset attribute of the thermal zone
259 * @tz: thermal zone device with the offset attribute
260 *
261 * Return: If the thermal zone device has a offset attribute, return it, else
262 * return 0.
263 */
thermal_zone_get_offset(struct thermal_zone_device * tz)264 int thermal_zone_get_offset(struct thermal_zone_device *tz)
265 {
266 if (tz && tz->tzp)
267 return tz->tzp->offset;
268 return 0;
269 }
270 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);
271