drivers/thermal/thermal_helpers.c

   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, 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
  42 static bool thermal_instance_present(struct thermal_zone_device *tz,
  43                                      struct thermal_cooling_device *cdev,
  44                                      const struct thermal_trip *trip)
  45 {
  46         struct thermal_instance *ti;
  47
  48         list_for_each_entry(ti, &tz->thermal_instances, tz_node) {
  49                 if (ti->trip == trip && ti->cdev == cdev)
  50                         return true;
  51         }
  52
  53         return false;
  54 }
  55
  56 bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
  57                                    const struct thermal_trip *trip,
  58                                    struct thermal_cooling_device *cdev)
  59 {
  60         bool ret;
  61
  62         mutex_lock(&tz->lock);
  63         mutex_lock(&cdev->lock);
  64
  65         ret = thermal_instance_present(tz, cdev, trip);
  66
  67         mutex_unlock(&cdev->lock);
  68         mutex_unlock(&tz->lock);
  69
  70         return ret;
  71 }
  72 EXPORT_SYMBOL_GPL(thermal_trip_is_bound_to_cdev);
  73
  74 /**
  75  * __thermal_zone_get_temp() - returns the temperature of a thermal zone
  76  * @tz: a valid pointer to a struct thermal_zone_device
  77  * @temp: a valid pointer to where to store the resulting temperature.
  78  *
  79  * When a valid thermal zone reference is passed, it will fetch its
  80  * temperature and fill @temp.
  81  *
  82  * Both tz and tz->ops must be valid pointers when calling this function,
  83  * and the tz->ops.get_temp callback must be provided.
  84  * The function must be called under tz->lock.
  85  *
  86  * Return: On success returns 0, an error code otherwise
  87  */
  88 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
  89 {
  90         const struct thermal_trip_desc *td;
  91         int crit_temp = INT_MAX;
  92         int ret = -EINVAL;
  93
  94         lockdep_assert_held(&tz->lock);
  95
  96         ret = tz->ops.get_temp(tz, temp);
  97
  98         if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
  99                 for_each_trip_desc(tz, td) {
 100                         const struct thermal_trip *trip = &td->trip;
 101
 102                         if (trip->type == THERMAL_TRIP_CRITICAL) {
 103                                 crit_temp = trip->temperature;
 104                                 break;
 105                         }
 106                 }
 107
 108                 /*
 109                  * Only allow emulating a temperature when the real temperature
 110                  * is below the critical temperature so that the emulation code
 111                  * cannot hide critical conditions.
 112                  */
 113                 if (!ret && *temp < crit_temp)
 114                         *temp = tz->emul_temperature;
 115         }
 116
 117         if (ret)
 118                 dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);
 119
 120         return ret;
 121 }
 122
 123 /**
 124  * thermal_zone_get_temp() - returns the temperature of a thermal zone
 125  * @tz: a valid pointer to a struct thermal_zone_device
 126  * @temp: a valid pointer to where to store the resulting temperature.
 127  *
 128  * When a valid thermal zone reference is passed, it will fetch its
 129  * temperature and fill @temp.
 130  *
 131  * Return: On success returns 0, an error code otherwise
 132  */
 133 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 134 {
 135         int ret;
 136
 137         if (IS_ERR_OR_NULL(tz))
 138                 return -EINVAL;
 139
 140         mutex_lock(&tz->lock);
 141
 142         if (!tz->ops.get_temp) {
 143                 ret = -EINVAL;
 144                 goto unlock;
 145         }
 146
 147         ret = __thermal_zone_get_temp(tz, temp);
 148         if (!ret && *temp <= THERMAL_TEMP_INVALID)
 149                 ret = -ENODATA;
 150
 151 unlock:
 152         mutex_unlock(&tz->lock);
 153
 154         return ret;
 155 }
 156 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 157
 158 static int thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, int state)
 159 {
 160         int ret;
 161
 162         /*
 163          * No check is needed for the ops->set_cur_state as the
 164          * registering function checked the ops are correctly set
 165          */
 166         ret = cdev->ops->set_cur_state(cdev, state);
 167         if (ret)
 168                 return ret;
 169
 170         thermal_notify_cdev_state_update(cdev, state);
 171         thermal_cooling_device_stats_update(cdev, state);
 172         thermal_debug_cdev_state_update(cdev, state);
 173
 174         return 0;
 175 }
 176
 177 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
 178 {
 179         struct thermal_instance *instance;
 180         unsigned long target = 0;
 181
 182         /* Make sure cdev enters the deepest cooling state */
 183         list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
 184                 if (instance->target == THERMAL_NO_TARGET)
 185                         continue;
 186                 if (instance->target > target)
 187                         target = instance->target;
 188         }
 189
 190         thermal_cdev_set_cur_state(cdev, target);
 191
 192         trace_cdev_update(cdev, target);
 193         dev_dbg(&cdev->device, "set to state %lu\n", target);
 194 }
 195
 196 /**
 197  * thermal_cdev_update - update cooling device state if needed
 198  * @cdev:       pointer to struct thermal_cooling_device
 199  *
 200  * Update the cooling device state if there is a need.
 201  */
 202 void thermal_cdev_update(struct thermal_cooling_device *cdev)
 203 {
 204         mutex_lock(&cdev->lock);
 205         if (!cdev->updated) {
 206                 __thermal_cdev_update(cdev);
 207                 cdev->updated = true;
 208         }
 209         mutex_unlock(&cdev->lock);
 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  */
 219 int thermal_zone_get_slope(struct thermal_zone_device *tz)
 220 {
 221         if (tz && tz->tzp)
 222                 return tz->tzp->slope;
 223         return 1;
 224 }
 225 EXPORT_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  */
 234 int thermal_zone_get_offset(struct thermal_zone_device *tz)
 235 {
 236         if (tz && tz->tzp)
 237                 return tz->tzp->offset;
 238         return 0;
 239 }
 240 EXPORT_SYMBOL_GPL(thermal_zone_get_offset);