| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * A power allocator to manage temperature |
| 4 | * |
| 5 | * Copyright (C) 2014 ARM Ltd. |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #define pr_fmt(fmt) "Power allocator: " fmt |
| 10 | |
| 11 | #include <linux/rculist.h> |
| 12 | #include <linux/slab.h> |
| 13 | #include <linux/thermal.h> |
| 14 | |
| 15 | #define CREATE_TRACE_POINTS |
| 16 | #include <trace/events/thermal_power_allocator.h> |
| 17 | |
| 18 | #include "thermal_core.h" |
| 19 | |
| 20 | #define INVALID_TRIP -1 |
| 21 | |
| 22 | #define FRAC_BITS 10 |
| 23 | #define int_to_frac(x) ((x) << FRAC_BITS) |
| 24 | #define frac_to_int(x) ((x) >> FRAC_BITS) |
| 25 | |
| 26 | /** |
| 27 | * mul_frac() - multiply two fixed-point numbers |
| 28 | * @x: first multiplicand |
| 29 | * @y: second multiplicand |
| 30 | * |
| 31 | * Return: the result of multiplying two fixed-point numbers. The |
| 32 | * result is also a fixed-point number. |
| 33 | */ |
| 34 | static inline s64 mul_frac(s64 x, s64 y) |
| 35 | { |
| 36 | return (x * y) >> FRAC_BITS; |
| 37 | } |
| 38 | |
| 39 | /** |
| 40 | * div_frac() - divide two fixed-point numbers |
| 41 | * @x: the dividend |
| 42 | * @y: the divisor |
| 43 | * |
| 44 | * Return: the result of dividing two fixed-point numbers. The |
| 45 | * result is also a fixed-point number. |
| 46 | */ |
| 47 | static inline s64 div_frac(s64 x, s64 y) |
| 48 | { |
| 49 | return div_s64(x << FRAC_BITS, y); |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * struct power_allocator_params - parameters for the power allocator governor |
| 54 | * @allocated_tzp: whether we have allocated tzp for this thermal zone and |
| 55 | * it needs to be freed on unbind |
| 56 | * @err_integral: accumulated error in the PID controller. |
| 57 | * @prev_err: error in the previous iteration of the PID controller. |
| 58 | * Used to calculate the derivative term. |
| 59 | * @trip_switch_on: first passive trip point of the thermal zone. The |
| 60 | * governor switches on when this trip point is crossed. |
| 61 | * If the thermal zone only has one passive trip point, |
| 62 | * @trip_switch_on should be INVALID_TRIP. |
| 63 | * @trip_max_desired_temperature: last passive trip point of the thermal |
| 64 | * zone. The temperature we are |
| 65 | * controlling for. |
| 66 | * @sustainable_power: Sustainable power (heat) that this thermal zone can |
| 67 | * dissipate |
| 68 | */ |
| 69 | struct power_allocator_params { |
| 70 | bool allocated_tzp; |
| 71 | s64 err_integral; |
| 72 | s32 prev_err; |
| 73 | int trip_switch_on; |
| 74 | int trip_max_desired_temperature; |
| 75 | u32 sustainable_power; |
| 76 | }; |
| 77 | |
| 78 | /** |
| 79 | * estimate_sustainable_power() - Estimate the sustainable power of a thermal zone |
| 80 | * @tz: thermal zone we are operating in |
| 81 | * |
| 82 | * For thermal zones that don't provide a sustainable_power in their |
| 83 | * thermal_zone_params, estimate one. Calculate it using the minimum |
| 84 | * power of all the cooling devices as that gives a valid value that |
| 85 | * can give some degree of functionality. For optimal performance of |
| 86 | * this governor, provide a sustainable_power in the thermal zone's |
| 87 | * thermal_zone_params. |
| 88 | */ |
| 89 | static u32 estimate_sustainable_power(struct thermal_zone_device *tz) |
| 90 | { |
| 91 | u32 sustainable_power = 0; |
| 92 | struct thermal_instance *instance; |
| 93 | struct power_allocator_params *params = tz->governor_data; |
| 94 | |
| 95 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 96 | struct thermal_cooling_device *cdev = instance->cdev; |
| 97 | u32 min_power; |
| 98 | |
| 99 | if (instance->trip != params->trip_max_desired_temperature) |
| 100 | continue; |
| 101 | |
| 102 | if (!cdev_is_power_actor(cdev)) |
| 103 | continue; |
| 104 | |
| 105 | if (cdev->ops->state2power(cdev, instance->upper, &min_power)) |
| 106 | continue; |
| 107 | |
| 108 | sustainable_power += min_power; |
| 109 | } |
| 110 | |
| 111 | return sustainable_power; |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * estimate_pid_constants() - Estimate the constants for the PID controller |
| 116 | * @tz: thermal zone for which to estimate the constants |
| 117 | * @sustainable_power: sustainable power for the thermal zone |
| 118 | * @trip_switch_on: trip point number for the switch on temperature |
| 119 | * @control_temp: target temperature for the power allocator governor |
| 120 | * |
| 121 | * This function is used to update the estimation of the PID |
| 122 | * controller constants in struct thermal_zone_parameters. |
| 123 | */ |
| 124 | static void estimate_pid_constants(struct thermal_zone_device *tz, |
| 125 | u32 sustainable_power, int trip_switch_on, |
| 126 | int control_temp) |
| 127 | { |
| 128 | int ret; |
| 129 | int switch_on_temp; |
| 130 | u32 temperature_threshold; |
| 131 | s32 k_i; |
| 132 | |
| 133 | ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp); |
| 134 | if (ret) |
| 135 | switch_on_temp = 0; |
| 136 | |
| 137 | temperature_threshold = control_temp - switch_on_temp; |
| 138 | /* |
| 139 | * estimate_pid_constants() tries to find appropriate default |
| 140 | * values for thermal zones that don't provide them. If a |
| 141 | * system integrator has configured a thermal zone with two |
| 142 | * passive trip points at the same temperature, that person |
| 143 | * hasn't put any effort to set up the thermal zone properly |
| 144 | * so just give up. |
| 145 | */ |
| 146 | if (!temperature_threshold) |
| 147 | return; |
| 148 | |
| 149 | tz->tzp->k_po = int_to_frac(sustainable_power) / |
| 150 | temperature_threshold; |
| 151 | |
| 152 | tz->tzp->k_pu = int_to_frac(2 * sustainable_power) / |
| 153 | temperature_threshold; |
| 154 | |
| 155 | k_i = tz->tzp->k_pu / 10; |
| 156 | tz->tzp->k_i = k_i > 0 ? k_i : 1; |
| 157 | |
| 158 | /* |
| 159 | * The default for k_d and integral_cutoff is 0, so we can |
| 160 | * leave them as they are. |
| 161 | */ |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * get_sustainable_power() - Get the right sustainable power |
| 166 | * @tz: thermal zone for which to estimate the constants |
| 167 | * @params: parameters for the power allocator governor |
| 168 | * @control_temp: target temperature for the power allocator governor |
| 169 | * |
| 170 | * This function is used for getting the proper sustainable power value based |
| 171 | * on variables which might be updated by the user sysfs interface. If that |
| 172 | * happen the new value is going to be estimated and updated. It is also used |
| 173 | * after thermal zone binding, where the initial values where set to 0. |
| 174 | */ |
| 175 | static u32 get_sustainable_power(struct thermal_zone_device *tz, |
| 176 | struct power_allocator_params *params, |
| 177 | int control_temp) |
| 178 | { |
| 179 | u32 sustainable_power; |
| 180 | |
| 181 | if (!tz->tzp->sustainable_power) |
| 182 | sustainable_power = estimate_sustainable_power(tz); |
| 183 | else |
| 184 | sustainable_power = tz->tzp->sustainable_power; |
| 185 | |
| 186 | /* Check if it's init value 0 or there was update via sysfs */ |
| 187 | if (sustainable_power != params->sustainable_power) { |
| 188 | estimate_pid_constants(tz, sustainable_power, |
| 189 | params->trip_switch_on, control_temp); |
| 190 | |
| 191 | /* Do the estimation only once and make available in sysfs */ |
| 192 | tz->tzp->sustainable_power = sustainable_power; |
| 193 | params->sustainable_power = sustainable_power; |
| 194 | } |
| 195 | |
| 196 | return sustainable_power; |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * pid_controller() - PID controller |
| 201 | * @tz: thermal zone we are operating in |
| 202 | * @control_temp: the target temperature in millicelsius |
| 203 | * @max_allocatable_power: maximum allocatable power for this thermal zone |
| 204 | * |
| 205 | * This PID controller increases the available power budget so that the |
| 206 | * temperature of the thermal zone gets as close as possible to |
| 207 | * @control_temp and limits the power if it exceeds it. k_po is the |
| 208 | * proportional term when we are overshooting, k_pu is the |
| 209 | * proportional term when we are undershooting. integral_cutoff is a |
| 210 | * threshold below which we stop accumulating the error. The |
| 211 | * accumulated error is only valid if the requested power will make |
| 212 | * the system warmer. If the system is mostly idle, there's no point |
| 213 | * in accumulating positive error. |
| 214 | * |
| 215 | * Return: The power budget for the next period. |
| 216 | */ |
| 217 | static u32 pid_controller(struct thermal_zone_device *tz, |
| 218 | int control_temp, |
| 219 | u32 max_allocatable_power) |
| 220 | { |
| 221 | s64 p, i, d, power_range; |
| 222 | s32 err, max_power_frac; |
| 223 | u32 sustainable_power; |
| 224 | struct power_allocator_params *params = tz->governor_data; |
| 225 | |
| 226 | max_power_frac = int_to_frac(max_allocatable_power); |
| 227 | |
| 228 | sustainable_power = get_sustainable_power(tz, params, control_temp); |
| 229 | |
| 230 | err = control_temp - tz->temperature; |
| 231 | err = int_to_frac(err); |
| 232 | |
| 233 | /* Calculate the proportional term */ |
| 234 | p = mul_frac(err < 0 ? tz->tzp->k_po : tz->tzp->k_pu, err); |
| 235 | |
| 236 | /* |
| 237 | * Calculate the integral term |
| 238 | * |
| 239 | * if the error is less than cut off allow integration (but |
| 240 | * the integral is limited to max power) |
| 241 | */ |
| 242 | i = mul_frac(tz->tzp->k_i, params->err_integral); |
| 243 | |
| 244 | if (err < int_to_frac(tz->tzp->integral_cutoff)) { |
| 245 | s64 i_next = i + mul_frac(tz->tzp->k_i, err); |
| 246 | |
| 247 | if (abs(i_next) < max_power_frac) { |
| 248 | i = i_next; |
| 249 | params->err_integral += err; |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | /* |
| 254 | * Calculate the derivative term |
| 255 | * |
| 256 | * We do err - prev_err, so with a positive k_d, a decreasing |
| 257 | * error (i.e. driving closer to the line) results in less |
| 258 | * power being applied, slowing down the controller) |
| 259 | */ |
| 260 | d = mul_frac(tz->tzp->k_d, err - params->prev_err); |
| 261 | d = div_frac(d, jiffies_to_msecs(tz->passive_delay_jiffies)); |
| 262 | params->prev_err = err; |
| 263 | |
| 264 | power_range = p + i + d; |
| 265 | |
| 266 | /* feed-forward the known sustainable dissipatable power */ |
| 267 | power_range = sustainable_power + frac_to_int(power_range); |
| 268 | |
| 269 | power_range = clamp(power_range, (s64)0, (s64)max_allocatable_power); |
| 270 | |
| 271 | trace_thermal_power_allocator_pid(tz, frac_to_int(err), |
| 272 | frac_to_int(params->err_integral), |
| 273 | frac_to_int(p), frac_to_int(i), |
| 274 | frac_to_int(d), power_range); |
| 275 | |
| 276 | return power_range; |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * power_actor_set_power() - limit the maximum power a cooling device consumes |
| 281 | * @cdev: pointer to &thermal_cooling_device |
| 282 | * @instance: thermal instance to update |
| 283 | * @power: the power in milliwatts |
| 284 | * |
| 285 | * Set the cooling device to consume at most @power milliwatts. The limit is |
| 286 | * expected to be a cap at the maximum power consumption. |
| 287 | * |
| 288 | * Return: 0 on success, -EINVAL if the cooling device does not |
| 289 | * implement the power actor API or -E* for other failures. |
| 290 | */ |
| 291 | static int |
| 292 | power_actor_set_power(struct thermal_cooling_device *cdev, |
| 293 | struct thermal_instance *instance, u32 power) |
| 294 | { |
| 295 | unsigned long state; |
| 296 | int ret; |
| 297 | |
| 298 | ret = cdev->ops->power2state(cdev, power, &state); |
| 299 | if (ret) |
| 300 | return ret; |
| 301 | |
| 302 | instance->target = clamp_val(state, instance->lower, instance->upper); |
| 303 | mutex_lock(&cdev->lock); |
| 304 | __thermal_cdev_update(cdev); |
| 305 | mutex_unlock(&cdev->lock); |
| 306 | |
| 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | /** |
| 311 | * divvy_up_power() - divvy the allocated power between the actors |
| 312 | * @req_power: each actor's requested power |
| 313 | * @max_power: each actor's maximum available power |
| 314 | * @num_actors: size of the @req_power, @max_power and @granted_power's array |
| 315 | * @total_req_power: sum of @req_power |
| 316 | * @power_range: total allocated power |
| 317 | * @granted_power: output array: each actor's granted power |
| 318 | * @extra_actor_power: an appropriately sized array to be used in the |
| 319 | * function as temporary storage of the extra power given |
| 320 | * to the actors |
| 321 | * |
| 322 | * This function divides the total allocated power (@power_range) |
| 323 | * fairly between the actors. It first tries to give each actor a |
| 324 | * share of the @power_range according to how much power it requested |
| 325 | * compared to the rest of the actors. For example, if only one actor |
| 326 | * requests power, then it receives all the @power_range. If |
| 327 | * three actors each requests 1mW, each receives a third of the |
| 328 | * @power_range. |
| 329 | * |
| 330 | * If any actor received more than their maximum power, then that |
| 331 | * surplus is re-divvied among the actors based on how far they are |
| 332 | * from their respective maximums. |
| 333 | * |
| 334 | * Granted power for each actor is written to @granted_power, which |
| 335 | * should've been allocated by the calling function. |
| 336 | */ |
| 337 | static void divvy_up_power(u32 *req_power, u32 *max_power, int num_actors, |
| 338 | u32 total_req_power, u32 power_range, |
| 339 | u32 *granted_power, u32 *extra_actor_power) |
| 340 | { |
| 341 | u32 extra_power, capped_extra_power; |
| 342 | int i; |
| 343 | |
| 344 | /* |
| 345 | * Prevent division by 0 if none of the actors request power. |
| 346 | */ |
| 347 | if (!total_req_power) |
| 348 | total_req_power = 1; |
| 349 | |
| 350 | capped_extra_power = 0; |
| 351 | extra_power = 0; |
| 352 | for (i = 0; i < num_actors; i++) { |
| 353 | u64 req_range = (u64)req_power[i] * power_range; |
| 354 | |
| 355 | granted_power[i] = DIV_ROUND_CLOSEST_ULL(req_range, |
| 356 | total_req_power); |
| 357 | |
| 358 | if (granted_power[i] > max_power[i]) { |
| 359 | extra_power += granted_power[i] - max_power[i]; |
| 360 | granted_power[i] = max_power[i]; |
| 361 | } |
| 362 | |
| 363 | extra_actor_power[i] = max_power[i] - granted_power[i]; |
| 364 | capped_extra_power += extra_actor_power[i]; |
| 365 | } |
| 366 | |
| 367 | if (!extra_power) |
| 368 | return; |
| 369 | |
| 370 | /* |
| 371 | * Re-divvy the reclaimed extra among actors based on |
| 372 | * how far they are from the max |
| 373 | */ |
| 374 | extra_power = min(extra_power, capped_extra_power); |
| 375 | if (capped_extra_power > 0) |
| 376 | for (i = 0; i < num_actors; i++) { |
| 377 | u64 extra_range = (u64)extra_actor_power[i] * extra_power; |
| 378 | granted_power[i] += DIV_ROUND_CLOSEST_ULL(extra_range, |
| 379 | capped_extra_power); |
| 380 | } |
| 381 | } |
| 382 | |
| 383 | static int allocate_power(struct thermal_zone_device *tz, |
| 384 | int control_temp) |
| 385 | { |
| 386 | struct thermal_instance *instance; |
| 387 | struct power_allocator_params *params = tz->governor_data; |
| 388 | u32 *req_power, *max_power, *granted_power, *extra_actor_power; |
| 389 | u32 *weighted_req_power; |
| 390 | u32 total_req_power, max_allocatable_power, total_weighted_req_power; |
| 391 | u32 total_granted_power, power_range; |
| 392 | int i, num_actors, total_weight, ret = 0; |
| 393 | int trip_max_desired_temperature = params->trip_max_desired_temperature; |
| 394 | |
| 395 | mutex_lock(&tz->lock); |
| 396 | |
| 397 | num_actors = 0; |
| 398 | total_weight = 0; |
| 399 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 400 | if ((instance->trip == trip_max_desired_temperature) && |
| 401 | cdev_is_power_actor(instance->cdev)) { |
| 402 | num_actors++; |
| 403 | total_weight += instance->weight; |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | if (!num_actors) { |
| 408 | ret = -ENODEV; |
| 409 | goto unlock; |
| 410 | } |
| 411 | |
| 412 | /* |
| 413 | * We need to allocate five arrays of the same size: |
| 414 | * req_power, max_power, granted_power, extra_actor_power and |
| 415 | * weighted_req_power. They are going to be needed until this |
| 416 | * function returns. Allocate them all in one go to simplify |
| 417 | * the allocation and deallocation logic. |
| 418 | */ |
| 419 | BUILD_BUG_ON(sizeof(*req_power) != sizeof(*max_power)); |
| 420 | BUILD_BUG_ON(sizeof(*req_power) != sizeof(*granted_power)); |
| 421 | BUILD_BUG_ON(sizeof(*req_power) != sizeof(*extra_actor_power)); |
| 422 | BUILD_BUG_ON(sizeof(*req_power) != sizeof(*weighted_req_power)); |
| 423 | req_power = kcalloc(num_actors * 5, sizeof(*req_power), GFP_KERNEL); |
| 424 | if (!req_power) { |
| 425 | ret = -ENOMEM; |
| 426 | goto unlock; |
| 427 | } |
| 428 | |
| 429 | max_power = &req_power[num_actors]; |
| 430 | granted_power = &req_power[2 * num_actors]; |
| 431 | extra_actor_power = &req_power[3 * num_actors]; |
| 432 | weighted_req_power = &req_power[4 * num_actors]; |
| 433 | |
| 434 | i = 0; |
| 435 | total_weighted_req_power = 0; |
| 436 | total_req_power = 0; |
| 437 | max_allocatable_power = 0; |
| 438 | |
| 439 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 440 | int weight; |
| 441 | struct thermal_cooling_device *cdev = instance->cdev; |
| 442 | |
| 443 | if (instance->trip != trip_max_desired_temperature) |
| 444 | continue; |
| 445 | |
| 446 | if (!cdev_is_power_actor(cdev)) |
| 447 | continue; |
| 448 | |
| 449 | if (cdev->ops->get_requested_power(cdev, &req_power[i])) |
| 450 | continue; |
| 451 | |
| 452 | if (!total_weight) |
| 453 | weight = 1 << FRAC_BITS; |
| 454 | else |
| 455 | weight = instance->weight; |
| 456 | |
| 457 | weighted_req_power[i] = frac_to_int(weight * req_power[i]); |
| 458 | |
| 459 | if (cdev->ops->state2power(cdev, instance->lower, |
| 460 | &max_power[i])) |
| 461 | continue; |
| 462 | |
| 463 | total_req_power += req_power[i]; |
| 464 | max_allocatable_power += max_power[i]; |
| 465 | total_weighted_req_power += weighted_req_power[i]; |
| 466 | |
| 467 | i++; |
| 468 | } |
| 469 | |
| 470 | power_range = pid_controller(tz, control_temp, max_allocatable_power); |
| 471 | |
| 472 | divvy_up_power(weighted_req_power, max_power, num_actors, |
| 473 | total_weighted_req_power, power_range, granted_power, |
| 474 | extra_actor_power); |
| 475 | |
| 476 | total_granted_power = 0; |
| 477 | i = 0; |
| 478 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 479 | if (instance->trip != trip_max_desired_temperature) |
| 480 | continue; |
| 481 | |
| 482 | if (!cdev_is_power_actor(instance->cdev)) |
| 483 | continue; |
| 484 | |
| 485 | power_actor_set_power(instance->cdev, instance, |
| 486 | granted_power[i]); |
| 487 | total_granted_power += granted_power[i]; |
| 488 | |
| 489 | i++; |
| 490 | } |
| 491 | |
| 492 | trace_thermal_power_allocator(tz, req_power, total_req_power, |
| 493 | granted_power, total_granted_power, |
| 494 | num_actors, power_range, |
| 495 | max_allocatable_power, tz->temperature, |
| 496 | control_temp - tz->temperature); |
| 497 | |
| 498 | kfree(req_power); |
| 499 | unlock: |
| 500 | mutex_unlock(&tz->lock); |
| 501 | |
| 502 | return ret; |
| 503 | } |
| 504 | |
| 505 | /** |
| 506 | * get_governor_trips() - get the number of the two trip points that are key for this governor |
| 507 | * @tz: thermal zone to operate on |
| 508 | * @params: pointer to private data for this governor |
| 509 | * |
| 510 | * The power allocator governor works optimally with two trips points: |
| 511 | * a "switch on" trip point and a "maximum desired temperature". These |
| 512 | * are defined as the first and last passive trip points. |
| 513 | * |
| 514 | * If there is only one trip point, then that's considered to be the |
| 515 | * "maximum desired temperature" trip point and the governor is always |
| 516 | * on. If there are no passive or active trip points, then the |
| 517 | * governor won't do anything. In fact, its throttle function |
| 518 | * won't be called at all. |
| 519 | */ |
| 520 | static void get_governor_trips(struct thermal_zone_device *tz, |
| 521 | struct power_allocator_params *params) |
| 522 | { |
| 523 | int i, last_active, last_passive; |
| 524 | bool found_first_passive; |
| 525 | |
| 526 | found_first_passive = false; |
| 527 | last_active = INVALID_TRIP; |
| 528 | last_passive = INVALID_TRIP; |
| 529 | |
| 530 | for (i = 0; i < tz->trips; i++) { |
| 531 | enum thermal_trip_type type; |
| 532 | int ret; |
| 533 | |
| 534 | ret = tz->ops->get_trip_type(tz, i, &type); |
| 535 | if (ret) { |
| 536 | dev_warn(&tz->device, |
| 537 | "Failed to get trip point %d type: %d\n", i, |
| 538 | ret); |
| 539 | continue; |
| 540 | } |
| 541 | |
| 542 | if (type == THERMAL_TRIP_PASSIVE) { |
| 543 | if (!found_first_passive) { |
| 544 | params->trip_switch_on = i; |
| 545 | found_first_passive = true; |
| 546 | } else { |
| 547 | last_passive = i; |
| 548 | } |
| 549 | } else if (type == THERMAL_TRIP_ACTIVE) { |
| 550 | last_active = i; |
| 551 | } else { |
| 552 | break; |
| 553 | } |
| 554 | } |
| 555 | |
| 556 | if (last_passive != INVALID_TRIP) { |
| 557 | params->trip_max_desired_temperature = last_passive; |
| 558 | } else if (found_first_passive) { |
| 559 | params->trip_max_desired_temperature = params->trip_switch_on; |
| 560 | params->trip_switch_on = INVALID_TRIP; |
| 561 | } else { |
| 562 | params->trip_switch_on = INVALID_TRIP; |
| 563 | params->trip_max_desired_temperature = last_active; |
| 564 | } |
| 565 | } |
| 566 | |
| 567 | static void reset_pid_controller(struct power_allocator_params *params) |
| 568 | { |
| 569 | params->err_integral = 0; |
| 570 | params->prev_err = 0; |
| 571 | } |
| 572 | |
| 573 | static void allow_maximum_power(struct thermal_zone_device *tz, bool update) |
| 574 | { |
| 575 | struct thermal_instance *instance; |
| 576 | struct power_allocator_params *params = tz->governor_data; |
| 577 | u32 req_power; |
| 578 | |
| 579 | mutex_lock(&tz->lock); |
| 580 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 581 | struct thermal_cooling_device *cdev = instance->cdev; |
| 582 | |
| 583 | if ((instance->trip != params->trip_max_desired_temperature) || |
| 584 | (!cdev_is_power_actor(instance->cdev))) |
| 585 | continue; |
| 586 | |
| 587 | instance->target = 0; |
| 588 | mutex_lock(&instance->cdev->lock); |
| 589 | /* |
| 590 | * Call for updating the cooling devices local stats and avoid |
| 591 | * periods of dozen of seconds when those have not been |
| 592 | * maintained. |
| 593 | */ |
| 594 | cdev->ops->get_requested_power(cdev, &req_power); |
| 595 | |
| 596 | if (update) |
| 597 | __thermal_cdev_update(instance->cdev); |
| 598 | |
| 599 | mutex_unlock(&instance->cdev->lock); |
| 600 | } |
| 601 | mutex_unlock(&tz->lock); |
| 602 | } |
| 603 | |
| 604 | /** |
| 605 | * check_power_actors() - Check all cooling devices and warn when they are |
| 606 | * not power actors |
| 607 | * @tz: thermal zone to operate on |
| 608 | * |
| 609 | * Check all cooling devices in the @tz and warn every time they are missing |
| 610 | * power actor API. The warning should help to investigate the issue, which |
| 611 | * could be e.g. lack of Energy Model for a given device. |
| 612 | * |
| 613 | * Return: 0 on success, -EINVAL if any cooling device does not implement |
| 614 | * the power actor API. |
| 615 | */ |
| 616 | static int check_power_actors(struct thermal_zone_device *tz) |
| 617 | { |
| 618 | struct thermal_instance *instance; |
| 619 | int ret = 0; |
| 620 | |
| 621 | list_for_each_entry(instance, &tz->thermal_instances, tz_node) { |
| 622 | if (!cdev_is_power_actor(instance->cdev)) { |
| 623 | dev_warn(&tz->device, "power_allocator: %s is not a power actor\n", |
| 624 | instance->cdev->type); |
| 625 | ret = -EINVAL; |
| 626 | } |
| 627 | } |
| 628 | |
| 629 | return ret; |
| 630 | } |
| 631 | |
| 632 | /** |
| 633 | * power_allocator_bind() - bind the power_allocator governor to a thermal zone |
| 634 | * @tz: thermal zone to bind it to |
| 635 | * |
| 636 | * Initialize the PID controller parameters and bind it to the thermal |
| 637 | * zone. |
| 638 | * |
| 639 | * Return: 0 on success, or -ENOMEM if we ran out of memory, or -EINVAL |
| 640 | * when there are unsupported cooling devices in the @tz. |
| 641 | */ |
| 642 | static int power_allocator_bind(struct thermal_zone_device *tz) |
| 643 | { |
| 644 | int ret; |
| 645 | struct power_allocator_params *params; |
| 646 | int control_temp; |
| 647 | |
| 648 | ret = check_power_actors(tz); |
| 649 | if (ret) |
| 650 | return ret; |
| 651 | |
| 652 | params = kzalloc(sizeof(*params), GFP_KERNEL); |
| 653 | if (!params) |
| 654 | return -ENOMEM; |
| 655 | |
| 656 | if (!tz->tzp) { |
| 657 | tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL); |
| 658 | if (!tz->tzp) { |
| 659 | ret = -ENOMEM; |
| 660 | goto free_params; |
| 661 | } |
| 662 | |
| 663 | params->allocated_tzp = true; |
| 664 | } |
| 665 | |
| 666 | if (!tz->tzp->sustainable_power) |
| 667 | dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n"); |
| 668 | |
| 669 | get_governor_trips(tz, params); |
| 670 | |
| 671 | if (tz->trips > 0) { |
| 672 | ret = tz->ops->get_trip_temp(tz, |
| 673 | params->trip_max_desired_temperature, |
| 674 | &control_temp); |
| 675 | if (!ret) |
| 676 | estimate_pid_constants(tz, tz->tzp->sustainable_power, |
| 677 | params->trip_switch_on, |
| 678 | control_temp); |
| 679 | } |
| 680 | |
| 681 | reset_pid_controller(params); |
| 682 | |
| 683 | tz->governor_data = params; |
| 684 | |
| 685 | return 0; |
| 686 | |
| 687 | free_params: |
| 688 | kfree(params); |
| 689 | |
| 690 | return ret; |
| 691 | } |
| 692 | |
| 693 | static void power_allocator_unbind(struct thermal_zone_device *tz) |
| 694 | { |
| 695 | struct power_allocator_params *params = tz->governor_data; |
| 696 | |
| 697 | dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id); |
| 698 | |
| 699 | if (params->allocated_tzp) { |
| 700 | kfree(tz->tzp); |
| 701 | tz->tzp = NULL; |
| 702 | } |
| 703 | |
| 704 | kfree(tz->governor_data); |
| 705 | tz->governor_data = NULL; |
| 706 | } |
| 707 | |
| 708 | static int power_allocator_throttle(struct thermal_zone_device *tz, int trip) |
| 709 | { |
| 710 | int ret; |
| 711 | int switch_on_temp, control_temp; |
| 712 | struct power_allocator_params *params = tz->governor_data; |
| 713 | bool update; |
| 714 | |
| 715 | /* |
| 716 | * We get called for every trip point but we only need to do |
| 717 | * our calculations once |
| 718 | */ |
| 719 | if (trip != params->trip_max_desired_temperature) |
| 720 | return 0; |
| 721 | |
| 722 | ret = tz->ops->get_trip_temp(tz, params->trip_switch_on, |
| 723 | &switch_on_temp); |
| 724 | if (!ret && (tz->temperature < switch_on_temp)) { |
| 725 | update = (tz->last_temperature >= switch_on_temp); |
| 726 | tz->passive = 0; |
| 727 | reset_pid_controller(params); |
| 728 | allow_maximum_power(tz, update); |
| 729 | return 0; |
| 730 | } |
| 731 | |
| 732 | tz->passive = 1; |
| 733 | |
| 734 | ret = tz->ops->get_trip_temp(tz, params->trip_max_desired_temperature, |
| 735 | &control_temp); |
| 736 | if (ret) { |
| 737 | dev_warn(&tz->device, |
| 738 | "Failed to get the maximum desired temperature: %d\n", |
| 739 | ret); |
| 740 | return ret; |
| 741 | } |
| 742 | |
| 743 | return allocate_power(tz, control_temp); |
| 744 | } |
| 745 | |
| 746 | static struct thermal_governor thermal_gov_power_allocator = { |
| 747 | .name = "power_allocator", |
| 748 | .bind_to_tz = power_allocator_bind, |
| 749 | .unbind_from_tz = power_allocator_unbind, |
| 750 | .throttle = power_allocator_throttle, |
| 751 | }; |
| 752 | THERMAL_GOVERNOR_DECLARE(thermal_gov_power_allocator); |