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_index)
46 {
47 	struct thermal_instance *pos = NULL;
48 	struct thermal_instance *target_instance = NULL;
49 	const struct thermal_trip *trip;
50 
51 	mutex_lock(&tz->lock);
52 	mutex_lock(&cdev->lock);
53 
54 	trip = &tz->trips[trip_index];
55 
56 	list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
57 		if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
58 			target_instance = pos;
59 			break;
60 		}
61 	}
62 
63 	mutex_unlock(&cdev->lock);
64 	mutex_unlock(&tz->lock);
65 
66 	return target_instance;
67 }
68 EXPORT_SYMBOL(get_thermal_instance);
69 
70 /**
71  * __thermal_zone_get_temp() - returns the temperature of a thermal zone
72  * @tz: a valid pointer to a struct thermal_zone_device
73  * @temp: a valid pointer to where to store the resulting temperature.
74  *
75  * When a valid thermal zone reference is passed, it will fetch its
76  * temperature and fill @temp.
77  *
78  * Both tz and tz->ops must be valid pointers when calling this function,
79  * and the tz->ops->get_temp callback must be provided.
80  * The function must be called under tz->lock.
81  *
82  * Return: On success returns 0, an error code otherwise
83  */
84 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
85 {
86 	int ret = -EINVAL;
87 	int count;
88 	int crit_temp = INT_MAX;
89 	struct thermal_trip trip;
90 
91 	lockdep_assert_held(&tz->lock);
92 
93 	ret = tz->ops->get_temp(tz, temp);
94 
95 	if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
96 		for (count = 0; count < tz->num_trips; count++) {
97 			ret = __thermal_zone_get_trip(tz, count, &trip);
98 			if (!ret && trip.type == THERMAL_TRIP_CRITICAL) {
99 				crit_temp = trip.temperature;
100 				break;
101 			}
102 		}
103 
104 		/*
105 		 * Only allow emulating a temperature when the real temperature
106 		 * is below the critical temperature so that the emulation code
107 		 * cannot hide critical conditions.
108 		 */
109 		if (!ret && *temp < crit_temp)
110 			*temp = tz->emul_temperature;
111 	}
112 
113 	if (ret)
114 		dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);
115 
116 	return ret;
117 }
118 
119 /**
120  * thermal_zone_get_temp() - returns the temperature of a thermal zone
121  * @tz: a valid pointer to a struct thermal_zone_device
122  * @temp: a valid pointer to where to store the resulting temperature.
123  *
124  * When a valid thermal zone reference is passed, it will fetch its
125  * temperature and fill @temp.
126  *
127  * Return: On success returns 0, an error code otherwise
128  */
129 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
130 {
131 	int ret;
132 
133 	if (IS_ERR_OR_NULL(tz))
134 		return -EINVAL;
135 
136 	mutex_lock(&tz->lock);
137 
138 	if (!tz->ops->get_temp) {
139 		ret = -EINVAL;
140 		goto unlock;
141 	}
142 
143 	if (device_is_registered(&tz->device))
144 		ret = __thermal_zone_get_temp(tz, temp);
145 	else
146 		ret = -ENODEV;
147 
148 unlock:
149 	mutex_unlock(&tz->lock);
150 
151 	return ret;
152 }
153 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
154 
155 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
156 				       int target)
157 {
158 	if (cdev->ops->set_cur_state(cdev, target))
159 		return;
160 
161 	thermal_notify_cdev_state_update(cdev->id, target);
162 	thermal_cooling_device_stats_update(cdev, target);
163 }
164 
165 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
166 {
167 	struct thermal_instance *instance;
168 	unsigned long target = 0;
169 
170 	/* Make sure cdev enters the deepest cooling state */
171 	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
172 		dev_dbg(&cdev->device, "zone%d->target=%lu\n",
173 			instance->tz->id, instance->target);
174 		if (instance->target == THERMAL_NO_TARGET)
175 			continue;
176 		if (instance->target > target)
177 			target = instance->target;
178 	}
179 
180 	thermal_cdev_set_cur_state(cdev, target);
181 
182 	trace_cdev_update(cdev, target);
183 	dev_dbg(&cdev->device, "set to state %lu\n", target);
184 }
185 
186 /**
187  * thermal_cdev_update - update cooling device state if needed
188  * @cdev:	pointer to struct thermal_cooling_device
189  *
190  * Update the cooling device state if there is a need.
191  */
192 void thermal_cdev_update(struct thermal_cooling_device *cdev)
193 {
194 	mutex_lock(&cdev->lock);
195 	if (!cdev->updated) {
196 		__thermal_cdev_update(cdev);
197 		cdev->updated = true;
198 	}
199 	mutex_unlock(&cdev->lock);
200 }
201 
202 /**
203  * thermal_zone_get_slope - return the slope attribute of the thermal zone
204  * @tz: thermal zone device with the slope attribute
205  *
206  * Return: If the thermal zone device has a slope attribute, return it, else
207  * return 1.
208  */
209 int thermal_zone_get_slope(struct thermal_zone_device *tz)
210 {
211 	if (tz && tz->tzp)
212 		return tz->tzp->slope;
213 	return 1;
214 }
215 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
216 
217 /**
218  * thermal_zone_get_offset - return the offset attribute of the thermal zone
219  * @tz: thermal zone device with the offset attribute
220  *
221  * Return: If the thermal zone device has a offset attribute, return it, else
222  * return 0.
223  */
224 int thermal_zone_get_offset(struct thermal_zone_device *tz)
225 {
226 	if (tz && tz->tzp)
227 		return tz->tzp->offset;
228 	return 0;
229 }
230 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);
231