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 26 int 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 } 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 * Both tz and tz->ops must be valid pointers when calling this function, 76 * and the tz->ops->get_temp callback must be provided. 77 * The function must be called under tz->lock. 78 * 79 * Return: On success returns 0, an error code otherwise 80 */ 81 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp) 82 { 83 int ret = -EINVAL; 84 int count; 85 int crit_temp = INT_MAX; 86 enum thermal_trip_type type; 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 (count = 0; count < tz->num_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 return ret; 112 } 113 114 /** 115 * thermal_zone_get_temp() - returns the temperature of a thermal zone 116 * @tz: a valid pointer to a struct thermal_zone_device 117 * @temp: a valid pointer to where to store the resulting temperature. 118 * 119 * When a valid thermal zone reference is passed, it will fetch its 120 * temperature and fill @temp. 121 * 122 * Return: On success returns 0, an error code otherwise 123 */ 124 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp) 125 { 126 int ret; 127 128 if (IS_ERR_OR_NULL(tz)) 129 return -EINVAL; 130 131 mutex_lock(&tz->lock); 132 133 if (!tz->ops->get_temp) { 134 ret = -EINVAL; 135 goto unlock; 136 } 137 138 if (device_is_registered(&tz->device)) 139 ret = __thermal_zone_get_temp(tz, temp); 140 else 141 ret = -ENODEV; 142 143 unlock: 144 mutex_unlock(&tz->lock); 145 146 return ret; 147 } 148 EXPORT_SYMBOL_GPL(thermal_zone_get_temp); 149 150 /** 151 * __thermal_zone_set_trips - Computes the next trip points for the driver 152 * @tz: a pointer to a thermal zone device structure 153 * 154 * The function computes the next temperature boundaries by browsing 155 * the trip points. The result is the closer low and high trip points 156 * to the current temperature. These values are passed to the backend 157 * driver to let it set its own notification mechanism (usually an 158 * interrupt). 159 * 160 * This function must be called with tz->lock held. Both tz and tz->ops 161 * must be valid pointers. 162 * 163 * It does not return a value 164 */ 165 void __thermal_zone_set_trips(struct thermal_zone_device *tz) 166 { 167 int low = -INT_MAX; 168 int high = INT_MAX; 169 int trip_temp, hysteresis; 170 int i, ret; 171 172 lockdep_assert_held(&tz->lock); 173 174 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst) 175 return; 176 177 for (i = 0; i < tz->num_trips; i++) { 178 int trip_low; 179 180 tz->ops->get_trip_temp(tz, i, &trip_temp); 181 tz->ops->get_trip_hyst(tz, i, &hysteresis); 182 183 trip_low = trip_temp - hysteresis; 184 185 if (trip_low < tz->temperature && trip_low > low) 186 low = trip_low; 187 188 if (trip_temp > tz->temperature && trip_temp < high) 189 high = trip_temp; 190 } 191 192 /* No need to change trip points */ 193 if (tz->prev_low_trip == low && tz->prev_high_trip == high) 194 return; 195 196 tz->prev_low_trip = low; 197 tz->prev_high_trip = high; 198 199 dev_dbg(&tz->device, 200 "new temperature boundaries: %d < x < %d\n", low, high); 201 202 /* 203 * Set a temperature window. When this window is left the driver 204 * must inform the thermal core via thermal_zone_device_update. 205 */ 206 ret = tz->ops->set_trips(tz, low, high); 207 if (ret) 208 dev_err(&tz->device, "Failed to set trips: %d\n", ret); 209 } 210 211 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, 212 int target) 213 { 214 if (cdev->ops->set_cur_state(cdev, target)) 215 return; 216 217 thermal_notify_cdev_state_update(cdev->id, target); 218 thermal_cooling_device_stats_update(cdev, target); 219 } 220 221 void __thermal_cdev_update(struct thermal_cooling_device *cdev) 222 { 223 struct thermal_instance *instance; 224 unsigned long target = 0; 225 226 /* Make sure cdev enters the deepest cooling state */ 227 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) { 228 dev_dbg(&cdev->device, "zone%d->target=%lu\n", 229 instance->tz->id, instance->target); 230 if (instance->target == THERMAL_NO_TARGET) 231 continue; 232 if (instance->target > target) 233 target = instance->target; 234 } 235 236 thermal_cdev_set_cur_state(cdev, target); 237 238 trace_cdev_update(cdev, target); 239 dev_dbg(&cdev->device, "set to state %lu\n", target); 240 } 241 242 /** 243 * thermal_cdev_update - update cooling device state if needed 244 * @cdev: pointer to struct thermal_cooling_device 245 * 246 * Update the cooling device state if there is a need. 247 */ 248 void thermal_cdev_update(struct thermal_cooling_device *cdev) 249 { 250 mutex_lock(&cdev->lock); 251 if (!cdev->updated) { 252 __thermal_cdev_update(cdev); 253 cdev->updated = true; 254 } 255 mutex_unlock(&cdev->lock); 256 } 257 258 /** 259 * thermal_zone_get_slope - return the slope attribute of the thermal zone 260 * @tz: thermal zone device with the slope attribute 261 * 262 * Return: If the thermal zone device has a slope attribute, return it, else 263 * return 1. 264 */ 265 int thermal_zone_get_slope(struct thermal_zone_device *tz) 266 { 267 if (tz && tz->tzp) 268 return tz->tzp->slope; 269 return 1; 270 } 271 EXPORT_SYMBOL_GPL(thermal_zone_get_slope); 272 273 /** 274 * thermal_zone_get_offset - return the offset attribute of the thermal zone 275 * @tz: thermal zone device with the offset attribute 276 * 277 * Return: If the thermal zone device has a offset attribute, return it, else 278 * return 0. 279 */ 280 int thermal_zone_get_offset(struct thermal_zone_device *tz) 281 { 282 if (tz && tz->tzp) 283 return tz->tzp->offset; 284 return 0; 285 } 286 EXPORT_SYMBOL_GPL(thermal_zone_get_offset); 287