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
 26int 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}
 42EXPORT_SYMBOL(get_tz_trend);
 43
 44struct thermal_instance *
 45get_thermal_instance(struct thermal_zone_device *tz,
 46		     struct thermal_cooling_device *cdev, int trip)
 47{
 48	struct thermal_instance *pos = NULL;
 49	struct thermal_instance *target_instance = NULL;
 50
 51	mutex_lock(&tz->lock);
 52	mutex_lock(&cdev->lock);
 53
 54	list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
 55		if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
 56			target_instance = pos;
 57			break;
 58		}
 59	}
 60
 61	mutex_unlock(&cdev->lock);
 62	mutex_unlock(&tz->lock);
 63
 64	return target_instance;
 65}
 66EXPORT_SYMBOL(get_thermal_instance);
 67
 68/**
 69 * thermal_zone_get_temp() - returns the temperature of a thermal zone
 70 * @tz: a valid pointer to a struct thermal_zone_device
 71 * @temp: a valid pointer to where to store the resulting temperature.
 72 *
 73 * When a valid thermal zone reference is passed, it will fetch its
 74 * temperature and fill @temp.
 75 *
 76 * Return: On success returns 0, an error code otherwise
 77 */
 78int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 79{
 80	int ret = -EINVAL;
 81	int count;
 82	int crit_temp = INT_MAX;
 83	enum thermal_trip_type type;
 84
 85	if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
 86		goto exit;
 87
 88	mutex_lock(&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->trips; count++) {
 94			ret = tz->ops->get_trip_type(tz, count, &type);
 95			if (!ret && type == THERMAL_TRIP_CRITICAL) {
 96				ret = tz->ops->get_trip_temp(tz, count,
 97						&crit_temp);
 98				break;
 99			}
100		}
101
102		/*
103		 * Only allow emulating a temperature when the real temperature
104		 * is below the critical temperature so that the emulation code
105		 * cannot hide critical conditions.
106		 */
107		if (!ret && *temp < crit_temp)
108			*temp = tz->emul_temperature;
109	}
110
111	mutex_unlock(&tz->lock);
112exit:
113	return ret;
114}
115EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
116
117/**
118 * thermal_zone_set_trips - Computes the next trip points for the driver
119 * @tz: a pointer to a thermal zone device structure
120 *
121 * The function computes the next temperature boundaries by browsing
122 * the trip points. The result is the closer low and high trip points
123 * to the current temperature. These values are passed to the backend
124 * driver to let it set its own notification mechanism (usually an
125 * interrupt).
126 *
127 * It does not return a value
128 */
129void thermal_zone_set_trips(struct thermal_zone_device *tz)
130{
131	int low = -INT_MAX;
132	int high = INT_MAX;
133	int trip_temp, hysteresis;
134	int i, ret;
135
136	mutex_lock(&tz->lock);
137
138	if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
139		goto exit;
140
141	for (i = 0; i < tz->trips; i++) {
142		int trip_low;
143
144		tz->ops->get_trip_temp(tz, i, &trip_temp);
145		tz->ops->get_trip_hyst(tz, i, &hysteresis);
146
147		trip_low = trip_temp - hysteresis;
148
149		if (trip_low < tz->temperature && trip_low > low)
150			low = trip_low;
151
152		if (trip_temp > tz->temperature && trip_temp < high)
153			high = trip_temp;
154	}
155
156	/* No need to change trip points */
157	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
158		goto exit;
159
160	tz->prev_low_trip = low;
161	tz->prev_high_trip = high;
162
163	dev_dbg(&tz->device,
164		"new temperature boundaries: %d < x < %d\n", low, high);
165
166	/*
167	 * Set a temperature window. When this window is left the driver
168	 * must inform the thermal core via thermal_zone_device_update.
169	 */
170	ret = tz->ops->set_trips(tz, low, high);
171	if (ret)
172		dev_err(&tz->device, "Failed to set trips: %d\n", ret);
173
174exit:
175	mutex_unlock(&tz->lock);
176}
177
178static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
179				       int target)
180{
181	if (cdev->ops->set_cur_state(cdev, target))
182		return;
183
184	thermal_notify_cdev_state_update(cdev->id, target);
185	thermal_cooling_device_stats_update(cdev, target);
186}
187
188void thermal_cdev_update(struct thermal_cooling_device *cdev)
189{
190	struct thermal_instance *instance;
191	unsigned long target = 0;
192
193	mutex_lock(&cdev->lock);
194	/* cooling device is updated*/
195	if (cdev->updated) {
196		mutex_unlock(&cdev->lock);
197		return;
198	}
199
200	/* Make sure cdev enters the deepest cooling state */
201	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
202		dev_dbg(&cdev->device, "zone%d->target=%lu\n",
203			instance->tz->id, instance->target);
204		if (instance->target == THERMAL_NO_TARGET)
205			continue;
206		if (instance->target > target)
207			target = instance->target;
208	}
209
210	thermal_cdev_set_cur_state(cdev, target);
211
212	cdev->updated = true;
213	mutex_unlock(&cdev->lock);
214	trace_cdev_update(cdev, target);
215	dev_dbg(&cdev->device, "set to state %lu\n", target);
216}
217EXPORT_SYMBOL(thermal_cdev_update);
218
219/**
220 * thermal_zone_get_slope - return the slope attribute of the thermal zone
221 * @tz: thermal zone device with the slope attribute
222 *
223 * Return: If the thermal zone device has a slope attribute, return it, else
224 * return 1.
225 */
226int thermal_zone_get_slope(struct thermal_zone_device *tz)
227{
228	if (tz && tz->tzp)
229		return tz->tzp->slope;
230	return 1;
231}
232EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
233
234/**
235 * thermal_zone_get_offset - return the offset attribute of the thermal zone
236 * @tz: thermal zone device with the offset attribute
237 *
238 * Return: If the thermal zone device has a offset attribute, return it, else
239 * return 0.
240 */
241int thermal_zone_get_offset(struct thermal_zone_device *tz)
242{
243	if (tz && tz->tzp)
244		return tz->tzp->offset;
245	return 0;
246}
247EXPORT_SYMBOL_GPL(thermal_zone_get_offset);