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 * Return: On success returns 0, an error code otherwise 76 */ 77 int 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->num_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); 111 exit: 112 return ret; 113 } 114 EXPORT_SYMBOL_GPL(thermal_zone_get_temp); 115 116 /** 117 * thermal_zone_set_trips - Computes the next trip points for the driver 118 * @tz: a pointer to a thermal zone device structure 119 * 120 * The function computes the next temperature boundaries by browsing 121 * the trip points. The result is the closer low and high trip points 122 * to the current temperature. These values are passed to the backend 123 * driver to let it set its own notification mechanism (usually an 124 * interrupt). 125 * 126 * It does not return a value 127 */ 128 void thermal_zone_set_trips(struct thermal_zone_device *tz) 129 { 130 int low = -INT_MAX; 131 int high = INT_MAX; 132 int trip_temp, hysteresis; 133 int i, ret; 134 135 mutex_lock(&tz->lock); 136 137 if (!tz->ops->set_trips || !tz->ops->get_trip_hyst) 138 goto exit; 139 140 for (i = 0; i < tz->num_trips; i++) { 141 int trip_low; 142 143 tz->ops->get_trip_temp(tz, i, &trip_temp); 144 tz->ops->get_trip_hyst(tz, i, &hysteresis); 145 146 trip_low = trip_temp - hysteresis; 147 148 if (trip_low < tz->temperature && trip_low > low) 149 low = trip_low; 150 151 if (trip_temp > tz->temperature && trip_temp < high) 152 high = trip_temp; 153 } 154 155 /* No need to change trip points */ 156 if (tz->prev_low_trip == low && tz->prev_high_trip == high) 157 goto exit; 158 159 tz->prev_low_trip = low; 160 tz->prev_high_trip = high; 161 162 dev_dbg(&tz->device, 163 "new temperature boundaries: %d < x < %d\n", low, high); 164 165 /* 166 * Set a temperature window. When this window is left the driver 167 * must inform the thermal core via thermal_zone_device_update. 168 */ 169 ret = tz->ops->set_trips(tz, low, high); 170 if (ret) 171 dev_err(&tz->device, "Failed to set trips: %d\n", ret); 172 173 exit: 174 mutex_unlock(&tz->lock); 175 } 176 177 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, 178 int target) 179 { 180 if (cdev->ops->set_cur_state(cdev, target)) 181 return; 182 183 thermal_notify_cdev_state_update(cdev->id, target); 184 thermal_cooling_device_stats_update(cdev, target); 185 } 186 187 void __thermal_cdev_update(struct thermal_cooling_device *cdev) 188 { 189 struct thermal_instance *instance; 190 unsigned long target = 0; 191 192 /* Make sure cdev enters the deepest cooling state */ 193 list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) { 194 dev_dbg(&cdev->device, "zone%d->target=%lu\n", 195 instance->tz->id, instance->target); 196 if (instance->target == THERMAL_NO_TARGET) 197 continue; 198 if (instance->target > target) 199 target = instance->target; 200 } 201 202 thermal_cdev_set_cur_state(cdev, target); 203 204 trace_cdev_update(cdev, target); 205 dev_dbg(&cdev->device, "set to state %lu\n", target); 206 } 207 208 /** 209 * thermal_cdev_update - update cooling device state if needed 210 * @cdev: pointer to struct thermal_cooling_device 211 * 212 * Update the cooling device state if there is a need. 213 */ 214 void thermal_cdev_update(struct thermal_cooling_device *cdev) 215 { 216 mutex_lock(&cdev->lock); 217 if (!cdev->updated) { 218 __thermal_cdev_update(cdev); 219 cdev->updated = true; 220 } 221 mutex_unlock(&cdev->lock); 222 } 223 224 /** 225 * thermal_zone_get_slope - return the slope attribute of the thermal zone 226 * @tz: thermal zone device with the slope attribute 227 * 228 * Return: If the thermal zone device has a slope attribute, return it, else 229 * return 1. 230 */ 231 int thermal_zone_get_slope(struct thermal_zone_device *tz) 232 { 233 if (tz && tz->tzp) 234 return tz->tzp->slope; 235 return 1; 236 } 237 EXPORT_SYMBOL_GPL(thermal_zone_get_slope); 238 239 /** 240 * thermal_zone_get_offset - return the offset attribute of the thermal zone 241 * @tz: thermal zone device with the offset attribute 242 * 243 * Return: If the thermal zone device has a offset attribute, return it, else 244 * return 0. 245 */ 246 int thermal_zone_get_offset(struct thermal_zone_device *tz) 247 { 248 if (tz && tz->tzp) 249 return tz->tzp->offset; 250 return 0; 251 } 252 EXPORT_SYMBOL_GPL(thermal_zone_get_offset); 253