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)
26 {
27 	enum thermal_trend trend;
28 
29 	if (tz->emul_temperature || !tz->ops->get_trend ||
30 	    tz->ops->get_trend(tz, trip, &trend)) {
31 		if (tz->temperature > tz->last_temperature)
32 			trend = THERMAL_TREND_RAISING;
33 		else if (tz->temperature < tz->last_temperature)
34 			trend = THERMAL_TREND_DROPPING;
35 		else
36 			trend = THERMAL_TREND_STABLE;
37 	}
38 
39 	return trend;
40 }
41 
42 struct thermal_instance *
43 get_thermal_instance(struct thermal_zone_device *tz,
44 		     struct thermal_cooling_device *cdev, int trip)
45 {
46 	struct thermal_instance *pos = NULL;
47 	struct thermal_instance *target_instance = NULL;
48 
49 	mutex_lock(&tz->lock);
50 	mutex_lock(&cdev->lock);
51 
52 	list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
53 		if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
54 			target_instance = pos;
55 			break;
56 		}
57 	}
58 
59 	mutex_unlock(&cdev->lock);
60 	mutex_unlock(&tz->lock);
61 
62 	return target_instance;
63 }
64 EXPORT_SYMBOL(get_thermal_instance);
65 
66 /**
67  * __thermal_zone_get_temp() - returns the temperature of a thermal zone
68  * @tz: a valid pointer to a struct thermal_zone_device
69  * @temp: a valid pointer to where to store the resulting temperature.
70  *
71  * When a valid thermal zone reference is passed, it will fetch its
72  * temperature and fill @temp.
73  *
74  * Both tz and tz->ops must be valid pointers when calling this function,
75  * and the tz->ops->get_temp callback must be provided.
76  * The function must be called under tz->lock.
77  *
78  * Return: On success returns 0, an error code otherwise
79  */
80 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
81 {
82 	int ret = -EINVAL;
83 	int count;
84 	int crit_temp = INT_MAX;
85 	struct thermal_trip trip;
86 
87 	lockdep_assert_held(&tz->lock);
88 
89 	ret = tz->ops->get_temp(tz, temp);
90 
91 	if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
92 		for (count = 0; count < tz->num_trips; count++) {
93 			ret = __thermal_zone_get_trip(tz, count, &trip);
94 			if (!ret && trip.type == THERMAL_TRIP_CRITICAL) {
95 				crit_temp = trip.temperature;
96 				break;
97 			}
98 		}
99 
100 		/*
101 		 * Only allow emulating a temperature when the real temperature
102 		 * is below the critical temperature so that the emulation code
103 		 * cannot hide critical conditions.
104 		 */
105 		if (!ret && *temp < crit_temp)
106 			*temp = tz->emul_temperature;
107 	}
108 
109 	if (ret)
110 		dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);
111 
112 	return ret;
113 }
114 
115 /**
116  * thermal_zone_get_temp() - returns the temperature of a thermal zone
117  * @tz: a valid pointer to a struct thermal_zone_device
118  * @temp: a valid pointer to where to store the resulting temperature.
119  *
120  * When a valid thermal zone reference is passed, it will fetch its
121  * temperature and fill @temp.
122  *
123  * Return: On success returns 0, an error code otherwise
124  */
125 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
126 {
127 	int ret;
128 
129 	if (IS_ERR_OR_NULL(tz))
130 		return -EINVAL;
131 
132 	mutex_lock(&tz->lock);
133 
134 	if (!tz->ops->get_temp) {
135 		ret = -EINVAL;
136 		goto unlock;
137 	}
138 
139 	if (device_is_registered(&tz->device))
140 		ret = __thermal_zone_get_temp(tz, temp);
141 	else
142 		ret = -ENODEV;
143 
144 unlock:
145 	mutex_unlock(&tz->lock);
146 
147 	return ret;
148 }
149 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
150 
151 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
152 				       int target)
153 {
154 	if (cdev->ops->set_cur_state(cdev, target))
155 		return;
156 
157 	thermal_notify_cdev_state_update(cdev->id, target);
158 	thermal_cooling_device_stats_update(cdev, target);
159 }
160 
161 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
162 {
163 	struct thermal_instance *instance;
164 	unsigned long target = 0;
165 
166 	/* Make sure cdev enters the deepest cooling state */
167 	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
168 		dev_dbg(&cdev->device, "zone%d->target=%lu\n",
169 			instance->tz->id, instance->target);
170 		if (instance->target == THERMAL_NO_TARGET)
171 			continue;
172 		if (instance->target > target)
173 			target = instance->target;
174 	}
175 
176 	thermal_cdev_set_cur_state(cdev, target);
177 
178 	trace_cdev_update(cdev, target);
179 	dev_dbg(&cdev->device, "set to state %lu\n", target);
180 }
181 
182 /**
183  * thermal_cdev_update - update cooling device state if needed
184  * @cdev:	pointer to struct thermal_cooling_device
185  *
186  * Update the cooling device state if there is a need.
187  */
188 void thermal_cdev_update(struct thermal_cooling_device *cdev)
189 {
190 	mutex_lock(&cdev->lock);
191 	if (!cdev->updated) {
192 		__thermal_cdev_update(cdev);
193 		cdev->updated = true;
194 	}
195 	mutex_unlock(&cdev->lock);
196 }
197 
198 /**
199  * thermal_zone_get_slope - return the slope attribute of the thermal zone
200  * @tz: thermal zone device with the slope attribute
201  *
202  * Return: If the thermal zone device has a slope attribute, return it, else
203  * return 1.
204  */
205 int thermal_zone_get_slope(struct thermal_zone_device *tz)
206 {
207 	if (tz && tz->tzp)
208 		return tz->tzp->slope;
209 	return 1;
210 }
211 EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
212 
213 /**
214  * thermal_zone_get_offset - return the offset attribute of the thermal zone
215  * @tz: thermal zone device with the offset attribute
216  *
217  * Return: If the thermal zone device has a offset attribute, return it, else
218  * return 0.
219  */
220 int thermal_zone_get_offset(struct thermal_zone_device *tz)
221 {
222 	if (tz && tz->tzp)
223 		return tz->tzp->offset;
224 	return 0;
225 }
226 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);
227