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
 25int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *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
 42static bool thermal_instance_present(struct thermal_zone_device *tz,
 43				     struct thermal_cooling_device *cdev,
 44				     const struct thermal_trip *trip)
 45{
 46	const struct thermal_trip_desc *td = trip_to_trip_desc(trip);
 47	struct thermal_instance *ti;
 48
 49	list_for_each_entry(ti, &td->thermal_instances, trip_node) {
 50		if (ti->cdev == cdev)
 51			return true;
 52	}
 53
 54	return false;
 55}
 56
 57bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
 58				   const struct thermal_trip *trip,
 59				   struct thermal_cooling_device *cdev)
 60{
 61	guard(thermal_zone)(tz);
 62	guard(cooling_dev)(cdev);
 63
 64	return thermal_instance_present(tz, cdev, trip);
 65}
 66EXPORT_SYMBOL_GPL(thermal_trip_is_bound_to_cdev);
 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 * Both tz and tz->ops must be valid pointers when calling this function,
 77 * and the tz->ops.get_temp callback must be provided.
 78 * The function must be called under tz->lock.
 79 *
 80 * Return: On success returns 0, an error code otherwise
 81 */
 82int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 83{
 84	const struct thermal_trip_desc *td;
 85	int crit_temp = INT_MAX;
 86	int ret = -EINVAL;
 87
 88	lockdep_assert_held(&tz->lock);
 89
 90	ret = tz->ops.get_temp(tz, temp);
 91
 92	if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
 93		for_each_trip_desc(tz, td) {
 94			const struct thermal_trip *trip = &td->trip;
 95
 96			if (trip->type == THERMAL_TRIP_CRITICAL) {
 97				crit_temp = trip->temperature;
 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	if (ret)
112		dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);
113
114	return ret;
115}
116
117/**
118 * thermal_zone_get_temp() - returns the temperature of a thermal zone
119 * @tz: a valid pointer to a struct thermal_zone_device
120 * @temp: a valid pointer to where to store the resulting temperature.
121 *
122 * When a valid thermal zone reference is passed, it will fetch its
123 * temperature and fill @temp.
124 *
125 * Return: On success returns 0, an error code otherwise
126 */
127int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
128{
129	int ret;
130
131	if (IS_ERR_OR_NULL(tz))
132		return -EINVAL;
133
134	guard(thermal_zone)(tz);
135
136	if (!tz->ops.get_temp)
137		return -EINVAL;
138
139	ret = __thermal_zone_get_temp(tz, temp);
140	if (!ret && *temp <= THERMAL_TEMP_INVALID)
141		return -ENODATA;
142
143	return ret;
144}
145EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
146
147static int thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, int state)
148{
149	int ret;
150
151	/*
152	 * No check is needed for the ops->set_cur_state as the
153	 * registering function checked the ops are correctly set
154	 */
155	ret = cdev->ops->set_cur_state(cdev, state);
156	if (ret)
157		return ret;
158
159	thermal_notify_cdev_state_update(cdev, state);
160	thermal_cooling_device_stats_update(cdev, state);
161	thermal_debug_cdev_state_update(cdev, state);
162
163	return 0;
164}
165
166void __thermal_cdev_update(struct thermal_cooling_device *cdev)
167{
168	struct thermal_instance *instance;
169	unsigned long target = 0;
170
171	/* Make sure cdev enters the deepest cooling state */
172	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
173		if (instance->target == THERMAL_NO_TARGET)
174			continue;
175		if (instance->target > target)
176			target = instance->target;
177	}
178
179	thermal_cdev_set_cur_state(cdev, target);
180
181	trace_cdev_update(cdev, target);
182	dev_dbg(&cdev->device, "set to state %lu\n", target);
183}
184
185/**
186 * thermal_cdev_update - update cooling device state if needed
187 * @cdev:	pointer to struct thermal_cooling_device
188 *
189 * Update the cooling device state if there is a need.
190 */
191void thermal_cdev_update(struct thermal_cooling_device *cdev)
192{
193	guard(cooling_dev)(cdev);
194
195	if (!cdev->updated) {
196		__thermal_cdev_update(cdev);
197		cdev->updated = true;
198	}
199}
200
201/**
202 * thermal_cdev_update_nocheck() - Unconditionally update cooling device state
203 * @cdev: Target cooling device.
204 */
205void thermal_cdev_update_nocheck(struct thermal_cooling_device *cdev)
206{
207	guard(cooling_dev)(cdev);
208
209	__thermal_cdev_update(cdev);
210}
211
212/**
213 * thermal_zone_get_slope - return the slope attribute of the thermal zone
214 * @tz: thermal zone device with the slope attribute
215 *
216 * Return: If the thermal zone device has a slope attribute, return it, else
217 * return 1.
218 */
219int thermal_zone_get_slope(struct thermal_zone_device *tz)
220{
221	if (tz && tz->tzp)
222		return tz->tzp->slope;
223	return 1;
224}
225EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
226
227/**
228 * thermal_zone_get_offset - return the offset attribute of the thermal zone
229 * @tz: thermal zone device with the offset attribute
230 *
231 * Return: If the thermal zone device has a offset attribute, return it, else
232 * return 0.
233 */
234int thermal_zone_get_offset(struct thermal_zone_device *tz)
235{
236	if (tz && tz->tzp)
237		return tz->tzp->offset;
238	return 0;
239}
240EXPORT_SYMBOL_GPL(thermal_zone_get_offset);