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/sysfs.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 
21 #include <trace/events/thermal.h>
22 
23 #include "thermal_core.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 EXPORT_SYMBOL(get_tz_trend);
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  * Return: On success returns 0, an error code otherwise
76  */
77 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
78 {
79 	int ret = -EINVAL;
80 	int count;
81 	int crit_temp = INT_MAX;
82 	enum thermal_trip_type type;
83 
84 	if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
85 		goto exit;
86 
87 	mutex_lock(&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->trips; count++) {
93 			ret = tz->ops->get_trip_type(tz, count, &type);
94 			if (!ret && type == THERMAL_TRIP_CRITICAL) {
95 				ret = tz->ops->get_trip_temp(tz, count,
96 						&crit_temp);
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 	mutex_unlock(&tz->lock);
111 exit:
112 	return ret;
113 }
114 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
115 
116 void thermal_zone_set_trips(struct thermal_zone_device *tz)
117 {
118 	int low = -INT_MAX;
119 	int high = INT_MAX;
120 	int trip_temp, hysteresis;
121 	int i, ret;
122 
123 	mutex_lock(&tz->lock);
124 
125 	if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
126 		goto exit;
127 
128 	for (i = 0; i < tz->trips; i++) {
129 		int trip_low;
130 
131 		tz->ops->get_trip_temp(tz, i, &trip_temp);
132 		tz->ops->get_trip_hyst(tz, i, &hysteresis);
133 
134 		trip_low = trip_temp - hysteresis;
135 
136 		if (trip_low < tz->temperature && trip_low > low)
137 			low = trip_low;
138 
139 		if (trip_temp > tz->temperature && trip_temp < high)
140 			high = trip_temp;
141 	}
142 
143 	/* No need to change trip points */
144 	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
145 		goto exit;
146 
147 	tz->prev_low_trip = low;
148 	tz->prev_high_trip = high;
149 
150 	dev_dbg(&tz->device,
151 		"new temperature boundaries: %d < x < %d\n", low, high);
152 
153 	/*
154 	 * Set a temperature window. When this window is left the driver
155 	 * must inform the thermal core via thermal_zone_device_update.
156 	 */
157 	ret = tz->ops->set_trips(tz, low, high);
158 	if (ret)
159 		dev_err(&tz->device, "Failed to set trips: %d\n", ret);
160 
161 exit:
162 	mutex_unlock(&tz->lock);
163 }
164 EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
165 
166 void thermal_cdev_update(struct thermal_cooling_device *cdev)
167 {
168 	struct thermal_instance *instance;
169 	unsigned long target = 0;
170 
171 	mutex_lock(&cdev->lock);
172 	/* cooling device is updated*/
173 	if (cdev->updated) {
174 		mutex_unlock(&cdev->lock);
175 		return;
176 	}
177 
178 	/* Make sure cdev enters the deepest cooling state */
179 	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
180 		dev_dbg(&cdev->device, "zone%d->target=%lu\n",
181 			instance->tz->id, instance->target);
182 		if (instance->target == THERMAL_NO_TARGET)
183 			continue;
184 		if (instance->target > target)
185 			target = instance->target;
186 	}
187 
188 	if (!cdev->ops->set_cur_state(cdev, target))
189 		thermal_cooling_device_stats_update(cdev, target);
190 
191 	cdev->updated = true;
192 	mutex_unlock(&cdev->lock);
193 	trace_cdev_update(cdev, target);
194 	dev_dbg(&cdev->device, "set to state %lu\n", target);
195 }
196 EXPORT_SYMBOL(thermal_cdev_update);
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