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 "thermal_core.h"
23 #include "thermal_trace.h"
24 
25 int get_tz_trend(struct thermal_zone_device *tz, int trip_index)
26 {
27 	struct thermal_trip *trip = tz->trips ? &tz->trips[trip_index] : NULL;
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 *
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 
67 /**
68  * __thermal_zone_get_temp() - returns the temperature of a thermal zone
69  * @tz: a valid pointer to a struct thermal_zone_device
70  * @temp: a valid pointer to where to store the resulting temperature.
71  *
72  * When a valid thermal zone reference is passed, it will fetch its
73  * temperature and fill @temp.
74  *
75  * Both tz and tz->ops must be valid pointers when calling this function,
76  * and the tz->ops->get_temp callback must be provided.
77  * The function must be called under tz->lock.
78  *
79  * Return: On success returns 0, an error code otherwise
80  */
81 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
82 {
83 	int ret = -EINVAL;
84 	int count;
85 	int crit_temp = INT_MAX;
86 	struct thermal_trip trip;
87 
88 	lockdep_assert_held(&tz->lock);
89 
90 	ret = tz->ops->get_temp(tz, temp);
91 
92 	if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
93 		for (count = 0; count < tz->num_trips; count++) {
94 			ret = __thermal_zone_get_trip(tz, count, &trip);
95 			if (!ret && trip.type == THERMAL_TRIP_CRITICAL) {
96 				crit_temp = trip.temperature;
97 				break;
98 			}
99 		}
100 
101 		/*
102 		 * Only allow emulating a temperature when the real temperature
103 		 * is below the critical temperature so that the emulation code
104 		 * cannot hide critical conditions.
105 		 */
106 		if (!ret && *temp < crit_temp)
107 			*temp = tz->emul_temperature;
108 	}
109 
110 	if (ret)
111 		dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);
112 
113 	return ret;
114 }
115 
116 /**
117  * thermal_zone_get_temp() - returns the temperature of a thermal zone
118  * @tz: a valid pointer to a struct thermal_zone_device
119  * @temp: a valid pointer to where to store the resulting temperature.
120  *
121  * When a valid thermal zone reference is passed, it will fetch its
122  * temperature and fill @temp.
123  *
124  * Return: On success returns 0, an error code otherwise
125  */
126 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
127 {
128 	int ret;
129 
130 	if (IS_ERR_OR_NULL(tz))
131 		return -EINVAL;
132 
133 	mutex_lock(&tz->lock);
134 
135 	if (!tz->ops->get_temp) {
136 		ret = -EINVAL;
137 		goto unlock;
138 	}
139 
140 	if (device_is_registered(&tz->device))
141 		ret = __thermal_zone_get_temp(tz, temp);
142 	else
143 		ret = -ENODEV;
144 
145 unlock:
146 	mutex_unlock(&tz->lock);
147 
148 	return ret;
149 }
150 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
151 
152 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
153 				       int target)
154 {
155 	if (cdev->ops->set_cur_state(cdev, target))
156 		return;
157 
158 	thermal_notify_cdev_state_update(cdev->id, target);
159 	thermal_cooling_device_stats_update(cdev, target);
160 }
161 
162 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
163 {
164 	struct thermal_instance *instance;
165 	unsigned long target = 0;
166 
167 	/* Make sure cdev enters the deepest cooling state */
168 	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
169 		dev_dbg(&cdev->device, "zone%d->target=%lu\n",
170 			instance->tz->id, instance->target);
171 		if (instance->target == THERMAL_NO_TARGET)
172 			continue;
173 		if (instance->target > target)
174 			target = instance->target;
175 	}
176 
177 	thermal_cdev_set_cur_state(cdev, target);
178 
179 	trace_cdev_update(cdev, target);
180 	dev_dbg(&cdev->device, "set to state %lu\n", target);
181 }
182 
183 /**
184  * thermal_cdev_update - update cooling device state if needed
185  * @cdev:	pointer to struct thermal_cooling_device
186  *
187  * Update the cooling device state if there is a need.
188  */
189 void thermal_cdev_update(struct thermal_cooling_device *cdev)
190 {
191 	mutex_lock(&cdev->lock);
192 	if (!cdev->updated) {
193 		__thermal_cdev_update(cdev);
194 		cdev->updated = true;
195 	}
196 	mutex_unlock(&cdev->lock);
197 }
198 
199 /**
200  * thermal_zone_get_slope - return the slope attribute of the thermal zone
201  * @tz: thermal zone device with the slope attribute
202  *
203  * Return: If the thermal zone device has a slope attribute, return it, else
204  * return 1.
205  */
206 int thermal_zone_get_slope(struct thermal_zone_device *tz)
207 {
208 	if (tz && tz->tzp)
209 		return tz->tzp->slope;
210 	return 1;
211 }
212 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
213 
214 /**
215  * thermal_zone_get_offset - return the offset attribute of the thermal zone
216  * @tz: thermal zone device with the offset attribute
217  *
218  * Return: If the thermal zone device has a offset attribute, return it, else
219  * return 0.
220  */
221 int thermal_zone_get_offset(struct thermal_zone_device *tz)
222 {
223 	if (tz && tz->tzp)
224 		return tz->tzp->offset;
225 	return 0;
226 }
227 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);
228