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
 25int 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}
 41EXPORT_SYMBOL(get_tz_trend);
 42
 43struct thermal_instance *
 44get_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}
 65EXPORT_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 */
 77int 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);
111exit:
112	return ret;
113}
114EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
115
116void 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
161exit:
162	mutex_unlock(&tz->lock);
163}
164EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
165
166void 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}
196EXPORT_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 */
205int thermal_zone_get_slope(struct thermal_zone_device *tz)
206{
207	if (tz && tz->tzp)
208		return tz->tzp->slope;
209	return 1;
210}
211EXPORT_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 */
220int thermal_zone_get_offset(struct thermal_zone_device *tz)
221{
222	if (tz && tz->tzp)
223		return tz->tzp->offset;
224	return 0;
225}
226EXPORT_SYMBOL_GPL(thermal_zone_get_offset);