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 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp) 68 { 69 int ret = -EINVAL; 70 int count; 71 int crit_temp = INT_MAX; 72 enum thermal_trip_type type; 73 74 lockdep_assert_held(&tz->lock); 75 76 if (!tz || IS_ERR(tz) || !tz->ops->get_temp) 77 return -EINVAL; 78 79 ret = tz->ops->get_temp(tz, temp); 80 81 if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) { 82 for (count = 0; count < tz->num_trips; count++) { 83 ret = tz->ops->get_trip_type(tz, count, &type); 84 if (!ret && type == THERMAL_TRIP_CRITICAL) { 85 ret = tz->ops->get_trip_temp(tz, count, 86 &crit_temp); 87 break; 88 } 89 } 90 91 /* 92 * Only allow emulating a temperature when the real temperature 93 * is below the critical temperature so that the emulation code 94 * cannot hide critical conditions. 95 */ 96 if (!ret && *temp < crit_temp) 97 *temp = tz->emul_temperature; 98 } 99 100 return ret; 101 } 102 103 /** 104 * thermal_zone_get_temp() - returns the temperature of a thermal zone 105 * @tz: a valid pointer to a struct thermal_zone_device 106 * @temp: a valid pointer to where to store the resulting temperature. 107 * 108 * When a valid thermal zone reference is passed, it will fetch its 109 * temperature and fill @temp. 110 * 111 * Return: On success returns 0, an error code otherwise 112 */ 113 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp) 114 { 115 int ret; 116 117 mutex_lock(&tz->lock); 118 ret = __thermal_zone_get_temp(tz, temp); 119 mutex_unlock(&tz->lock); 120 121 return ret; 122 } 123 EXPORT_SYMBOL_GPL(thermal_zone_get_temp); 124 125 void __thermal_zone_set_trips(struct thermal_zone_device *tz) 126 { 127 int low = -INT_MAX; 128 int high = INT_MAX; 129 int trip_temp, hysteresis; 130 int i, ret; 131 132 lockdep_assert_held(&tz->lock); 133 134 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst) 135 return; 136 137 for (i = 0; i < tz->num_trips; i++) { 138 int trip_low; 139 140 tz->ops->get_trip_temp(tz, i, &trip_temp); 141 tz->ops->get_trip_hyst(tz, i, &hysteresis); 142 143 trip_low = trip_temp - hysteresis; 144 145 if (trip_low < tz->temperature && trip_low > low) 146 low = trip_low; 147 148 if (trip_temp > tz->temperature && trip_temp < high) 149 high = trip_temp; 150 } 151 152 /* No need to change trip points */ 153 if (tz->prev_low_trip == low && tz->prev_high_trip == high) 154 return; 155 156 tz->prev_low_trip = low; 157 tz->prev_high_trip = high; 158 159 dev_dbg(&tz->device, 160 "new temperature boundaries: %d < x < %d\n", low, high); 161 162 /* 163 * Set a temperature window. When this window is left the driver 164 * must inform the thermal core via thermal_zone_device_update. 165 */ 166 ret = tz->ops->set_trips(tz, low, high); 167 if (ret) 168 dev_err(&tz->device, "Failed to set trips: %d\n", ret); 169 } 170 171 /** 172 * thermal_zone_set_trips - Computes the next trip points for the driver 173 * @tz: a pointer to a thermal zone device structure 174 * 175 * The function computes the next temperature boundaries by browsing 176 * the trip points. The result is the closer low and high trip points 177 * to the current temperature. These values are passed to the backend 178 * driver to let it set its own notification mechanism (usually an 179 * interrupt). 180 * 181 * It does not return a value 182 */ 183 void thermal_zone_set_trips(struct thermal_zone_device *tz) 184 { 185 mutex_lock(&tz->lock); 186 __thermal_zone_set_trips(tz); 187 mutex_unlock(&tz->lock); 188 } 189 190 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, 191 int target) 192 { 193 if (cdev->ops->set_cur_state(cdev, target)) 194 return; 195 196 thermal_notify_cdev_state_update(cdev->id, target); 197 thermal_cooling_device_stats_update(cdev, target); 198 } 199 200 void __thermal_cdev_update(struct thermal_cooling_device *cdev) 201 { 202 struct thermal_instance *instance; 203 unsigned long target = 0; 204 205 /* Make sure cdev enters the deepest cooling state */ 206 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) { 207 dev_dbg(&cdev->device, "zone%d->target=%lu\n", 208 instance->tz->id, instance->target); 209 if (instance->target == THERMAL_NO_TARGET) 210 continue; 211 if (instance->target > target) 212 target = instance->target; 213 } 214 215 thermal_cdev_set_cur_state(cdev, target); 216 217 trace_cdev_update(cdev, target); 218 dev_dbg(&cdev->device, "set to state %lu\n", target); 219 } 220 221 /** 222 * thermal_cdev_update - update cooling device state if needed 223 * @cdev: pointer to struct thermal_cooling_device 224 * 225 * Update the cooling device state if there is a need. 226 */ 227 void thermal_cdev_update(struct thermal_cooling_device *cdev) 228 { 229 mutex_lock(&cdev->lock); 230 if (!cdev->updated) { 231 __thermal_cdev_update(cdev); 232 cdev->updated = true; 233 } 234 mutex_unlock(&cdev->lock); 235 } 236 237 /** 238 * thermal_zone_get_slope - return the slope attribute of the thermal zone 239 * @tz: thermal zone device with the slope attribute 240 * 241 * Return: If the thermal zone device has a slope attribute, return it, else 242 * return 1. 243 */ 244 int thermal_zone_get_slope(struct thermal_zone_device *tz) 245 { 246 if (tz && tz->tzp) 247 return tz->tzp->slope; 248 return 1; 249 } 250 EXPORT_SYMBOL_GPL(thermal_zone_get_slope); 251 252 /** 253 * thermal_zone_get_offset - return the offset attribute of the thermal zone 254 * @tz: thermal zone device with the offset attribute 255 * 256 * Return: If the thermal zone device has a offset attribute, return it, else 257 * return 0. 258 */ 259 int thermal_zone_get_offset(struct thermal_zone_device *tz) 260 { 261 if (tz && tz->tzp) 262 return tz->tzp->offset; 263 return 0; 264 } 265 EXPORT_SYMBOL_GPL(thermal_zone_get_offset); 266