drivers/thermal/step_wise.c

   1 /*
   2  *  step_wise.c - A step-by-step Thermal throttling governor
   3  *
   4  *  Copyright (C) 2012 Intel Corp
   5  *  Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
   6  *
   7  *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; version 2 of the License.
  12  *
  13  *  This program is distributed in the hope that it will be useful, but
  14  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *  General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License along
  19  *  with this program; if not, write to the Free Software Foundation, Inc.,
  20  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  21  *
  22  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  23  */
  24
  25 #include <linux/thermal.h>
  26
  27 #include "thermal_core.h"
  28
  29 /*
  30  * If the temperature is higher than a trip point,
  31  *    a. if the trend is THERMAL_TREND_RAISING, use higher cooling
  32  *       state for this trip point
  33  *    b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
  34  *       state for this trip point
  35  *    c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
  36  *       for this trip point
  37  *    d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
  38  *       for this trip point
  39  * If the temperature is lower than a trip point,
  40  *    a. if the trend is THERMAL_TREND_RAISING, do nothing
  41  *    b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
  42  *       state for this trip point, if the cooling state already
  43  *       equals lower limit, deactivate the thermal instance
  44  *    c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
  45  *    d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
  46  *       if the cooling state already equals lower limit,
  47  *       deactive the thermal instance
  48  */
  49 #if 0
  50 static unsigned long get_target_state(struct thermal_instance *instance,
  51                                 enum thermal_trend trend, bool throttle)
  52 {
  53         struct thermal_cooling_device *cdev = instance->cdev;
  54         unsigned long cur_state;
  55
  56         cdev->ops->get_cur_state(cdev, &cur_state);
  57         dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
  58
  59         switch (trend) {
  60         case THERMAL_TREND_RAISING:
  61                 if (throttle) {
  62                         cur_state = cur_state < instance->upper ?
  63                                     (cur_state + 1) : instance->upper;
  64                         if (cur_state < instance->lower)
  65                                 cur_state = instance->lower;
  66                 }
  67                 break;
  68         case THERMAL_TREND_RAISE_FULL:
  69                 if (throttle)
  70                         cur_state = instance->upper;
  71                 break;
  72         case THERMAL_TREND_DROPPING:
  73                 if (cur_state == instance->lower) {
  74                         if (!throttle)
  75                                 cur_state = -1;
  76                 } else {
  77                         cur_state -= 1;
  78                         if (cur_state > instance->upper)
  79                                 cur_state = instance->upper;
  80                 }
  81                 break;
  82         case THERMAL_TREND_DROP_FULL:
  83                 if (cur_state == instance->lower) {
  84                         if (!throttle)
  85                                 cur_state = -1;
  86                 } else
  87                         cur_state = instance->lower;
  88                 break;
  89         default:
  90                 break;
  91         }
  92
  93         return cur_state;
  94 }
  95
  96 static void update_passive_instance(struct thermal_zone_device *tz,
  97                                 enum thermal_trip_type type, int value)
  98 {
  99         /*
 100          * If value is +1, activate a passive instance.
 101          * If value is -1, deactivate a passive instance.
 102          */
 103         if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE)
 104                 tz->passive += value;
 105 }
 106
 107 static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 108 {
 109         long trip_temp;
 110         enum thermal_trip_type trip_type;
 111         enum thermal_trend trend;
 112         struct thermal_instance *instance;
 113         bool throttle = false;
 114         int old_target;
 115
 116         if (trip == THERMAL_TRIPS_NONE) {
 117                 trip_temp = tz->forced_passive;
 118                 trip_type = THERMAL_TRIPS_NONE;
 119         } else {
 120                 tz->ops->get_trip_temp(tz, trip, &trip_temp);
 121                 tz->ops->get_trip_type(tz, trip, &trip_type);
 122         }
 123
 124         trend = get_tz_trend(tz, trip);
 125
 126         if (tz->temperature >= trip_temp)
 127                 throttle = true;
 128
 129         dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
 130                                 trip, trip_type, trip_temp, trend, throttle);
 131
 132         mutex_lock(&tz->lock);
 133
 134         list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
 135                 if (instance->trip != trip)
 136                         continue;
 137
 138                 old_target = instance->target;
 139                 instance->target = get_target_state(instance, trend, throttle);
 140                 dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
 141                                         old_target, (int)instance->target);
 142
 143                 /* Activate a passive thermal instance */
 144                 if (old_target == THERMAL_NO_TARGET &&
 145                         instance->target != THERMAL_NO_TARGET)
 146                         update_passive_instance(tz, trip_type, 1);
 147                 /* Deactivate a passive thermal instance */
 148                 else if (old_target != THERMAL_NO_TARGET &&
 149                         instance->target == THERMAL_NO_TARGET)
 150                         update_passive_instance(tz, trip_type, -1);
 151
 152
 153                 instance->cdev->updated = false; /* cdev needs update */
 154         }
 155
 156         mutex_unlock(&tz->lock);
 157 }
 158 #else
 159
 160 static int get_hyst_target(struct thermal_zone_device *tz)
 161 {
 162         int count;
 163         unsigned long trip_temp, trip_hyst, hyst_temp;
 164
 165         if (tz->trips == 0 || !tz->ops->get_trip_hyst){
 166                 return 0;
 167         }
 168         for (count = 0; count < tz->trips; count++) {
 169                 tz->ops->get_trip_temp(tz, count, &trip_temp);
 170                 tz->ops->get_trip_hyst(tz, count, &trip_hyst);
 171                 hyst_temp = trip_temp - trip_hyst;
 172                 printk("trip:%d, temp:%d, hyst_temp:%d\n", count, tz->temperature, hyst_temp);
 173                 if (tz->temperature < (long)hyst_temp  + TRIP_TEMP_OFFSET)
 174                         break;
 175         }
 176         return count;
 177 }
 178
 179 static int get_trip_target(struct thermal_zone_device *tz)
 180 {
 181         int count = 0;
 182         unsigned long trip_temp;
 183
 184         if (tz->trips == 0 || !tz->ops->get_trip_temp)
 185                 return 0;
 186
 187         for (count = 0; count < tz->trips; count++) {
 188                 tz->ops->get_trip_temp(tz, count, &trip_temp);
 189                 printk("trip:%d, temp:%d, trip_temp:%d\n", count, tz->temperature, trip_temp);
 190                 if (tz->temperature < (long)trip_temp  - TRIP_TEMP_OFFSET)
 191                         break;
 192         }
 193         return count;
 194 }
 195
 196 static int get_step_wise_target(struct thermal_instance *instance,
 197                 struct thermal_zone_device *tz, int trip)
 198 {
 199         struct thermal_cooling_device *cdev = instance->cdev;
 200         enum thermal_trend trend;
 201         unsigned long cur_target;
 202         unsigned long new_target;
 203
 204         cur_target = instance->target;
 205         printk("%s: %s trip:%d cur_target:%d\n", cdev->type, __func__, trip, cur_target);
 206         if (cur_target == THERMAL_NO_TARGET){
 207                 cur_target = instance->lower;
 208         }
 209         if (tz->ops->get_trend){
 210                 tz->ops->get_trend(tz, trip, &trend);
 211         }else{
 212                 new_target = get_trip_target(tz);
 213                 printk("%s: %s trip:%d new_target:%d\n", cdev->type, __func__, trip, new_target);
 214                 if (new_target < cur_target){
 215                         trend = THERMAL_TREND_DROPPING;
 216                         if (!tz->ops->get_trip_hyst){
 217                                 goto dropping;
 218                         }
 219                 }else if(new_target >= cur_target){
 220                         goto raising;
 221                 }
 222         }
 223         switch (trend){
 224                 case THERMAL_TREND_RAISING:
 225                         new_target = get_trip_target(tz);
 226                         printk("%s: %s trend raising, target:%d\n", cdev->type, __func__, new_target);
 227                         goto raising;
 228                 case THERMAL_TREND_DROPPING:
 229                         if (tz->ops->get_trip_hyst){
 230                                 new_target = get_hyst_target(tz);
 231                         }else{
 232                                 new_target = get_trip_target(tz);
 233                         }
 234                         printk("%s: %s trend dropping, target:%d\n", cdev->type, __func__, new_target);
 235                         goto dropping;
 236                 case THERMAL_TREND_STABLE:
 237                 default:
 238                         printk("%s: %s trend stable\n", cdev->type, __func__);
 239                         return instance->lower;
 240         }
 241 raising:
 242         if (new_target > cur_target){
 243                 ++cur_target;
 244         }
 245         return cur_target;
 246 dropping:
 247         if (new_target < cur_target){
 248                 --cur_target;
 249         }
 250         return cur_target;
 251
 252 }
 253
 254 static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 255 {
 256         struct thermal_instance *instance;
 257         unsigned long target;
 258
 259         mutex_lock(&tz->lock);
 260         list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
 261                 if (instance->trip != trip)
 262                         continue;
 263                 target = get_step_wise_target(instance, tz, trip);
 264                 printk("%s: get target_state: %d\n", instance->cdev->type, target);
 265                 if (target == THERMAL_NO_TARGET){
 266                         continue;
 267                 }
 268                 if (target < instance->lower){
 269                         target = instance->lower;
 270                 }
 271                 if (target > instance->upper){
 272                         target = instance->upper;
 273                 }
 274                 instance->target  = target;
 275                 instance->cdev->updated = false; /* cdev needs update */
 276         }
 277         mutex_unlock(&tz->lock);
 278
 279         return;
 280 }
 281 #endif
 282
 283 /**
 284  * step_wise_throttle - throttles devices asscciated with the given zone
 285  * @tz - thermal_zone_device
 286  * @trip - the trip point
 287  * @trip_type - type of the trip point
 288  *
 289  * Throttling Logic: This uses the trend of the thermal zone to throttle.
 290  * If the thermal zone is 'heating up' this throttles all the cooling
 291  * devices associated with the zone and its particular trip point, by one
 292  * step. If the zone is 'cooling down' it brings back the performance of
 293  * the devices by one step.
 294  */
 295 static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
 296 {
 297         struct thermal_instance *instance;
 298
 299         thermal_zone_trip_update(tz, trip);
 300
 301         if (tz->forced_passive)
 302                 thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
 303
 304         mutex_lock(&tz->lock);
 305
 306         list_for_each_entry(instance, &tz->thermal_instances, tz_node)
 307                 thermal_cdev_update(instance->cdev);
 308
 309         mutex_unlock(&tz->lock);
 310
 311         return 0;
 312 }
 313
 314 static struct thermal_governor thermal_gov_step_wise = {
 315         .name           = "step_wise",
 316         .throttle       = step_wise_throttle,
 317 };
 318
 319 int thermal_gov_step_wise_register(void)
 320 {
 321         return thermal_register_governor(&thermal_gov_step_wise);
 322 }
 323
 324 void thermal_gov_step_wise_unregister(void)
 325 {
 326         thermal_unregister_governor(&thermal_gov_step_wise);
 327 }