drivers/thermal/cpufreq_cooling.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/drivers/thermal/cpufreq_cooling.c
   4  *
   5  *  Copyright (C) 2012  Samsung Electronics Co., Ltd(http://www.samsung.com)
   6  *
   7  *  Copyright (C) 2012-2018 Linaro Limited.
   8  *
   9  *  Authors:    Amit Daniel <amit.kachhap@linaro.org>
  10  *              Viresh Kumar <viresh.kumar@linaro.org>
  11  *
  12  */
  13 #include <linux/cpu.h>
  14 #include <linux/cpufreq.h>
  15 #include <linux/cpu_cooling.h>
  16 #include <linux/energy_model.h>
  17 #include <linux/err.h>
  18 #include <linux/export.h>
  19 #include <linux/idr.h>
  20 #include <linux/pm_opp.h>
  21 #include <linux/pm_qos.h>
  22 #include <linux/slab.h>
  23 #include <linux/thermal.h>
  24
  25 #include <trace/events/thermal.h>
  26
  27 /*
  28  * Cooling state <-> CPUFreq frequency
  29  *
  30  * Cooling states are translated to frequencies throughout this driver and this
  31  * is the relation between them.
  32  *
  33  * Highest cooling state corresponds to lowest possible frequency.
  34  *
  35  * i.e.
  36  *      level 0 --> 1st Max Freq
  37  *      level 1 --> 2nd Max Freq
  38  *      ...
  39  */
  40
  41 /**
  42  * struct time_in_idle - Idle time stats
  43  * @time: previous reading of the absolute time that this cpu was idle
  44  * @timestamp: wall time of the last invocation of get_cpu_idle_time_us()
  45  */
  46 struct time_in_idle {
  47         u64 time;
  48         u64 timestamp;
  49 };
  50
  51 /**
  52  * struct cpufreq_cooling_device - data for cooling device with cpufreq
  53  * @id: unique integer value corresponding to each cpufreq_cooling_device
  54  *      registered.
  55  * @last_load: load measured by the latest call to cpufreq_get_requested_power()
  56  * @cpufreq_state: integer value representing the current state of cpufreq
  57  *      cooling devices.
  58  * @max_level: maximum cooling level. One less than total number of valid
  59  *      cpufreq frequencies.
  60  * @em: Reference on the Energy Model of the device
  61  * @cdev: thermal_cooling_device pointer to keep track of the
  62  *      registered cooling device.
  63  * @policy: cpufreq policy.
  64  * @node: list_head to link all cpufreq_cooling_device together.
  65  * @idle_time: idle time stats
  66  * @qos_req: PM QoS contraint to apply
  67  *
  68  * This structure is required for keeping information of each registered
  69  * cpufreq_cooling_device.
  70  */
  71 struct cpufreq_cooling_device {
  72         int id;
  73         u32 last_load;
  74         unsigned int cpufreq_state;
  75         unsigned int max_level;
  76         struct em_perf_domain *em;
  77         struct cpufreq_policy *policy;
  78         struct list_head node;
  79 #ifndef CONFIG_SMP
  80         struct time_in_idle *idle_time;
  81 #endif
  82         struct freq_qos_request qos_req;
  83 };
  84
  85 static DEFINE_IDA(cpufreq_ida);
  86 static DEFINE_MUTEX(cooling_list_lock);
  87 static LIST_HEAD(cpufreq_cdev_list);
  88
  89 #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
  90 /**
  91  * get_level: Find the level for a particular frequency
  92  * @cpufreq_cdev: cpufreq_cdev for which the property is required
  93  * @freq: Frequency
  94  *
  95  * Return: level corresponding to the frequency.
  96  */
  97 static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_cdev,
  98                                unsigned int freq)
  99 {
 100         int i;
 101
 102         for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
 103                 if (freq > cpufreq_cdev->em->table[i].frequency)
 104                         break;
 105         }
 106
 107         return cpufreq_cdev->max_level - i - 1;
 108 }
 109
 110 static u32 cpu_freq_to_power(struct cpufreq_cooling_device *cpufreq_cdev,
 111                              u32 freq)
 112 {
 113         int i;
 114
 115         for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
 116                 if (freq > cpufreq_cdev->em->table[i].frequency)
 117                         break;
 118         }
 119
 120         return cpufreq_cdev->em->table[i + 1].power;
 121 }
 122
 123 static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
 124                              u32 power)
 125 {
 126         int i;
 127
 128         for (i = cpufreq_cdev->max_level; i >= 0; i--) {
 129                 if (power >= cpufreq_cdev->em->table[i].power)
 130                         break;
 131         }
 132
 133         return cpufreq_cdev->em->table[i].frequency;
 134 }
 135
 136 /**
 137  * get_load() - get load for a cpu
 138  * @cpufreq_cdev: struct cpufreq_cooling_device for the cpu
 139  * @cpu: cpu number
 140  * @cpu_idx: index of the cpu in time_in_idle array
 141  *
 142  * Return: The average load of cpu @cpu in percentage since this
 143  * function was last called.
 144  */
 145 #ifdef CONFIG_SMP
 146 static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
 147                     int cpu_idx)
 148 {
 149         unsigned long max = arch_scale_cpu_capacity(cpu);
 150         unsigned long util;
 151
 152         util = sched_cpu_util(cpu, max);
 153         return (util * 100) / max;
 154 }
 155 #else /* !CONFIG_SMP */
 156 static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
 157                     int cpu_idx)
 158 {
 159         u32 load;
 160         u64 now, now_idle, delta_time, delta_idle;
 161         struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx];
 162
 163         now_idle = get_cpu_idle_time(cpu, &now, 0);
 164         delta_idle = now_idle - idle_time->time;
 165         delta_time = now - idle_time->timestamp;
 166
 167         if (delta_time <= delta_idle)
 168                 load = 0;
 169         else
 170                 load = div64_u64(100 * (delta_time - delta_idle), delta_time);
 171
 172         idle_time->time = now_idle;
 173         idle_time->timestamp = now;
 174
 175         return load;
 176 }
 177 #endif /* CONFIG_SMP */
 178
 179 /**
 180  * get_dynamic_power() - calculate the dynamic power
 181  * @cpufreq_cdev:       &cpufreq_cooling_device for this cdev
 182  * @freq:       current frequency
 183  *
 184  * Return: the dynamic power consumed by the cpus described by
 185  * @cpufreq_cdev.
 186  */
 187 static u32 get_dynamic_power(struct cpufreq_cooling_device *cpufreq_cdev,
 188                              unsigned long freq)
 189 {
 190         u32 raw_cpu_power;
 191
 192         raw_cpu_power = cpu_freq_to_power(cpufreq_cdev, freq);
 193         return (raw_cpu_power * cpufreq_cdev->last_load) / 100;
 194 }
 195
 196 /**
 197  * cpufreq_get_requested_power() - get the current power
 198  * @cdev:       &thermal_cooling_device pointer
 199  * @power:      pointer in which to store the resulting power
 200  *
 201  * Calculate the current power consumption of the cpus in milliwatts
 202  * and store it in @power.  This function should actually calculate
 203  * the requested power, but it's hard to get the frequency that
 204  * cpufreq would have assigned if there were no thermal limits.
 205  * Instead, we calculate the current power on the assumption that the
 206  * immediate future will look like the immediate past.
 207  *
 208  * We use the current frequency and the average load since this
 209  * function was last called.  In reality, there could have been
 210  * multiple opps since this function was last called and that affects
 211  * the load calculation.  While it's not perfectly accurate, this
 212  * simplification is good enough and works.  REVISIT this, as more
 213  * complex code may be needed if experiments show that it's not
 214  * accurate enough.
 215  *
 216  * Return: 0 on success, -E* if getting the static power failed.
 217  */
 218 static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev,
 219                                        u32 *power)
 220 {
 221         unsigned long freq;
 222         int i = 0, cpu;
 223         u32 total_load = 0;
 224         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 225         struct cpufreq_policy *policy = cpufreq_cdev->policy;
 226         u32 *load_cpu = NULL;
 227
 228         freq = cpufreq_quick_get(policy->cpu);
 229
 230         if (trace_thermal_power_cpu_get_power_enabled()) {
 231                 u32 ncpus = cpumask_weight(policy->related_cpus);
 232
 233                 load_cpu = kcalloc(ncpus, sizeof(*load_cpu), GFP_KERNEL);
 234         }
 235
 236         for_each_cpu(cpu, policy->related_cpus) {
 237                 u32 load;
 238
 239                 if (cpu_online(cpu))
 240                         load = get_load(cpufreq_cdev, cpu, i);
 241                 else
 242                         load = 0;
 243
 244                 total_load += load;
 245                 if (load_cpu)
 246                         load_cpu[i] = load;
 247
 248                 i++;
 249         }
 250
 251         cpufreq_cdev->last_load = total_load;
 252
 253         *power = get_dynamic_power(cpufreq_cdev, freq);
 254
 255         if (load_cpu) {
 256                 trace_thermal_power_cpu_get_power(policy->related_cpus, freq,
 257                                                   load_cpu, i, *power);
 258
 259                 kfree(load_cpu);
 260         }
 261
 262         return 0;
 263 }
 264
 265 /**
 266  * cpufreq_state2power() - convert a cpu cdev state to power consumed
 267  * @cdev:       &thermal_cooling_device pointer
 268  * @state:      cooling device state to be converted
 269  * @power:      pointer in which to store the resulting power
 270  *
 271  * Convert cooling device state @state into power consumption in
 272  * milliwatts assuming 100% load.  Store the calculated power in
 273  * @power.
 274  *
 275  * Return: 0 on success, -EINVAL if the cooling device state could not
 276  * be converted into a frequency or other -E* if there was an error
 277  * when calculating the static power.
 278  */
 279 static int cpufreq_state2power(struct thermal_cooling_device *cdev,
 280                                unsigned long state, u32 *power)
 281 {
 282         unsigned int freq, num_cpus, idx;
 283         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 284
 285         /* Request state should be less than max_level */
 286         if (state > cpufreq_cdev->max_level)
 287                 return -EINVAL;
 288
 289         num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus);
 290
 291         idx = cpufreq_cdev->max_level - state;
 292         freq = cpufreq_cdev->em->table[idx].frequency;
 293         *power = cpu_freq_to_power(cpufreq_cdev, freq) * num_cpus;
 294
 295         return 0;
 296 }
 297
 298 /**
 299  * cpufreq_power2state() - convert power to a cooling device state
 300  * @cdev:       &thermal_cooling_device pointer
 301  * @power:      power in milliwatts to be converted
 302  * @state:      pointer in which to store the resulting state
 303  *
 304  * Calculate a cooling device state for the cpus described by @cdev
 305  * that would allow them to consume at most @power mW and store it in
 306  * @state.  Note that this calculation depends on external factors
 307  * such as the cpu load or the current static power.  Calling this
 308  * function with the same power as input can yield different cooling
 309  * device states depending on those external factors.
 310  *
 311  * Return: 0 on success, -ENODEV if no cpus are online or -EINVAL if
 312  * the calculated frequency could not be converted to a valid state.
 313  * The latter should not happen unless the frequencies available to
 314  * cpufreq have changed since the initialization of the cpu cooling
 315  * device.
 316  */
 317 static int cpufreq_power2state(struct thermal_cooling_device *cdev,
 318                                u32 power, unsigned long *state)
 319 {
 320         unsigned int target_freq;
 321         u32 last_load, normalised_power;
 322         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 323         struct cpufreq_policy *policy = cpufreq_cdev->policy;
 324
 325         last_load = cpufreq_cdev->last_load ?: 1;
 326         normalised_power = (power * 100) / last_load;
 327         target_freq = cpu_power_to_freq(cpufreq_cdev, normalised_power);
 328
 329         *state = get_level(cpufreq_cdev, target_freq);
 330         trace_thermal_power_cpu_limit(policy->related_cpus, target_freq, *state,
 331                                       power);
 332         return 0;
 333 }
 334
 335 static inline bool em_is_sane(struct cpufreq_cooling_device *cpufreq_cdev,
 336                               struct em_perf_domain *em) {
 337         struct cpufreq_policy *policy;
 338         unsigned int nr_levels;
 339
 340         if (!em)
 341                 return false;
 342
 343         policy = cpufreq_cdev->policy;
 344         if (!cpumask_equal(policy->related_cpus, em_span_cpus(em))) {
 345                 pr_err("The span of pd %*pbl is misaligned with cpufreq policy %*pbl\n",
 346                         cpumask_pr_args(em_span_cpus(em)),
 347                         cpumask_pr_args(policy->related_cpus));
 348                 return false;
 349         }
 350
 351         nr_levels = cpufreq_cdev->max_level + 1;
 352         if (em_pd_nr_perf_states(em) != nr_levels) {
 353                 pr_err("The number of performance states in pd %*pbl (%u) doesn't match the number of cooling levels (%u)\n",
 354                         cpumask_pr_args(em_span_cpus(em)),
 355                         em_pd_nr_perf_states(em), nr_levels);
 356                 return false;
 357         }
 358
 359         return true;
 360 }
 361 #endif /* CONFIG_THERMAL_GOV_POWER_ALLOCATOR */
 362
 363 #ifdef CONFIG_SMP
 364 static inline int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
 365 {
 366         return 0;
 367 }
 368
 369 static inline void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
 370 {
 371 }
 372 #else
 373 static int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
 374 {
 375         unsigned int num_cpus = cpumask_weight(cpufreq_cdev->policy->related_cpus);
 376
 377         cpufreq_cdev->idle_time = kcalloc(num_cpus,
 378                                           sizeof(*cpufreq_cdev->idle_time),
 379                                           GFP_KERNEL);
 380         if (!cpufreq_cdev->idle_time)
 381                 return -ENOMEM;
 382
 383         return 0;
 384 }
 385
 386 static void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
 387 {
 388         kfree(cpufreq_cdev->idle_time);
 389         cpufreq_cdev->idle_time = NULL;
 390 }
 391 #endif /* CONFIG_SMP */
 392
 393 static unsigned int get_state_freq(struct cpufreq_cooling_device *cpufreq_cdev,
 394                                    unsigned long state)
 395 {
 396         struct cpufreq_policy *policy;
 397         unsigned long idx;
 398
 399 #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
 400         /* Use the Energy Model table if available */
 401         if (cpufreq_cdev->em) {
 402                 idx = cpufreq_cdev->max_level - state;
 403                 return cpufreq_cdev->em->table[idx].frequency;
 404         }
 405 #endif
 406
 407         /* Otherwise, fallback on the CPUFreq table */
 408         policy = cpufreq_cdev->policy;
 409         if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
 410                 idx = cpufreq_cdev->max_level - state;
 411         else
 412                 idx = state;
 413
 414         return policy->freq_table[idx].frequency;
 415 }
 416
 417 /* cpufreq cooling device callback functions are defined below */
 418
 419 /**
 420  * cpufreq_get_max_state - callback function to get the max cooling state.
 421  * @cdev: thermal cooling device pointer.
 422  * @state: fill this variable with the max cooling state.
 423  *
 424  * Callback for the thermal cooling device to return the cpufreq
 425  * max cooling state.
 426  *
 427  * Return: 0 on success, an error code otherwise.
 428  */
 429 static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
 430                                  unsigned long *state)
 431 {
 432         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 433
 434         *state = cpufreq_cdev->max_level;
 435         return 0;
 436 }
 437
 438 /**
 439  * cpufreq_get_cur_state - callback function to get the current cooling state.
 440  * @cdev: thermal cooling device pointer.
 441  * @state: fill this variable with the current cooling state.
 442  *
 443  * Callback for the thermal cooling device to return the cpufreq
 444  * current cooling state.
 445  *
 446  * Return: 0 on success, an error code otherwise.
 447  */
 448 static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
 449                                  unsigned long *state)
 450 {
 451         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 452
 453         *state = cpufreq_cdev->cpufreq_state;
 454
 455         return 0;
 456 }
 457
 458 /**
 459  * cpufreq_set_cur_state - callback function to set the current cooling state.
 460  * @cdev: thermal cooling device pointer.
 461  * @state: set this variable to the current cooling state.
 462  *
 463  * Callback for the thermal cooling device to change the cpufreq
 464  * current cooling state.
 465  *
 466  * Return: 0 on success, an error code otherwise.
 467  */
 468 static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
 469                                  unsigned long state)
 470 {
 471         struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
 472         struct cpumask *cpus;
 473         unsigned int frequency;
 474         unsigned long max_capacity, capacity;
 475         int ret;
 476
 477         /* Request state should be less than max_level */
 478         if (state > cpufreq_cdev->max_level)
 479                 return -EINVAL;
 480
 481         /* Check if the old cooling action is same as new cooling action */
 482         if (cpufreq_cdev->cpufreq_state == state)
 483                 return 0;
 484
 485         frequency = get_state_freq(cpufreq_cdev, state);
 486
 487         ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
 488         if (ret >= 0) {
 489                 cpufreq_cdev->cpufreq_state = state;
 490                 cpus = cpufreq_cdev->policy->cpus;
 491                 max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));
 492                 capacity = frequency * max_capacity;
 493                 capacity /= cpufreq_cdev->policy->cpuinfo.max_freq;
 494                 arch_set_thermal_pressure(cpus, max_capacity - capacity);
 495                 ret = 0;
 496         }
 497
 498         return ret;
 499 }
 500
 501 /* Bind cpufreq callbacks to thermal cooling device ops */
 502
 503 static struct thermal_cooling_device_ops cpufreq_cooling_ops = {
 504         .get_max_state          = cpufreq_get_max_state,
 505         .get_cur_state          = cpufreq_get_cur_state,
 506         .set_cur_state          = cpufreq_set_cur_state,
 507 };
 508
 509 /**
 510  * __cpufreq_cooling_register - helper function to create cpufreq cooling device
 511  * @np: a valid struct device_node to the cooling device device tree node
 512  * @policy: cpufreq policy
 513  * Normally this should be same as cpufreq policy->related_cpus.
 514  * @em: Energy Model of the cpufreq policy
 515  *
 516  * This interface function registers the cpufreq cooling device with the name
 517  * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
 518  * cooling devices. It also gives the opportunity to link the cooling device
 519  * with a device tree node, in order to bind it via the thermal DT code.
 520  *
 521  * Return: a valid struct thermal_cooling_device pointer on success,
 522  * on failure, it returns a corresponding ERR_PTR().
 523  */
 524 static struct thermal_cooling_device *
 525 __cpufreq_cooling_register(struct device_node *np,
 526                         struct cpufreq_policy *policy,
 527                         struct em_perf_domain *em)
 528 {
 529         struct thermal_cooling_device *cdev;
 530         struct cpufreq_cooling_device *cpufreq_cdev;
 531         char dev_name[THERMAL_NAME_LENGTH];
 532         unsigned int i;
 533         struct device *dev;
 534         int ret;
 535         struct thermal_cooling_device_ops *cooling_ops;
 536
 537         dev = get_cpu_device(policy->cpu);
 538         if (unlikely(!dev)) {
 539                 pr_warn("No cpu device for cpu %d\n", policy->cpu);
 540                 return ERR_PTR(-ENODEV);
 541         }
 542
 543         if (IS_ERR_OR_NULL(policy)) {
 544                 pr_err("%s: cpufreq policy isn't valid: %p\n", __func__, policy);
 545                 return ERR_PTR(-EINVAL);
 546         }
 547
 548         i = cpufreq_table_count_valid_entries(policy);
 549         if (!i) {
 550                 pr_debug("%s: CPUFreq table not found or has no valid entries\n",
 551                          __func__);
 552                 return ERR_PTR(-ENODEV);
 553         }
 554
 555         cpufreq_cdev = kzalloc(sizeof(*cpufreq_cdev), GFP_KERNEL);
 556         if (!cpufreq_cdev)
 557                 return ERR_PTR(-ENOMEM);
 558
 559         cpufreq_cdev->policy = policy;
 560
 561         ret = allocate_idle_time(cpufreq_cdev);
 562         if (ret) {
 563                 cdev = ERR_PTR(ret);
 564                 goto free_cdev;
 565         }
 566
 567         /* max_level is an index, not a counter */
 568         cpufreq_cdev->max_level = i - 1;
 569
 570         ret = ida_simple_get(&cpufreq_ida, 0, 0, GFP_KERNEL);
 571         if (ret < 0) {
 572                 cdev = ERR_PTR(ret);
 573                 goto free_idle_time;
 574         }
 575         cpufreq_cdev->id = ret;
 576
 577         snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
 578                  cpufreq_cdev->id);
 579
 580         cooling_ops = &cpufreq_cooling_ops;
 581
 582 #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
 583         if (em_is_sane(cpufreq_cdev, em)) {
 584                 cpufreq_cdev->em = em;
 585                 cooling_ops->get_requested_power = cpufreq_get_requested_power;
 586                 cooling_ops->state2power = cpufreq_state2power;
 587                 cooling_ops->power2state = cpufreq_power2state;
 588         } else
 589 #endif
 590         if (policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED) {
 591                 pr_err("%s: unsorted frequency tables are not supported\n",
 592                        __func__);
 593                 cdev = ERR_PTR(-EINVAL);
 594                 goto remove_ida;
 595         }
 596
 597         ret = freq_qos_add_request(&policy->constraints,
 598                                    &cpufreq_cdev->qos_req, FREQ_QOS_MAX,
 599                                    get_state_freq(cpufreq_cdev, 0));
 600         if (ret < 0) {
 601                 pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
 602                        ret);
 603                 cdev = ERR_PTR(ret);
 604                 goto remove_ida;
 605         }
 606
 607         cdev = thermal_of_cooling_device_register(np, dev_name, cpufreq_cdev,
 608                                                   cooling_ops);
 609         if (IS_ERR(cdev))
 610                 goto remove_qos_req;
 611
 612         mutex_lock(&cooling_list_lock);
 613         list_add(&cpufreq_cdev->node, &cpufreq_cdev_list);
 614         mutex_unlock(&cooling_list_lock);
 615
 616         return cdev;
 617
 618 remove_qos_req:
 619         freq_qos_remove_request(&cpufreq_cdev->qos_req);
 620 remove_ida:
 621         ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
 622 free_idle_time:
 623         free_idle_time(cpufreq_cdev);
 624 free_cdev:
 625         kfree(cpufreq_cdev);
 626         return cdev;
 627 }
 628
 629 /**
 630  * cpufreq_cooling_register - function to create cpufreq cooling device.
 631  * @policy: cpufreq policy
 632  *
 633  * This interface function registers the cpufreq cooling device with the name
 634  * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
 635  * cooling devices.
 636  *
 637  * Return: a valid struct thermal_cooling_device pointer on success,
 638  * on failure, it returns a corresponding ERR_PTR().
 639  */
 640 struct thermal_cooling_device *
 641 cpufreq_cooling_register(struct cpufreq_policy *policy)
 642 {
 643         return __cpufreq_cooling_register(NULL, policy, NULL);
 644 }
 645 EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
 646
 647 /**
 648  * of_cpufreq_cooling_register - function to create cpufreq cooling device.
 649  * @policy: cpufreq policy
 650  *
 651  * This interface function registers the cpufreq cooling device with the name
 652  * "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
 653  * cooling devices. Using this API, the cpufreq cooling device will be
 654  * linked to the device tree node provided.
 655  *
 656  * Using this function, the cooling device will implement the power
 657  * extensions by using a simple cpu power model.  The cpus must have
 658  * registered their OPPs using the OPP library.
 659  *
 660  * It also takes into account, if property present in policy CPU node, the
 661  * static power consumed by the cpu.
 662  *
 663  * Return: a valid struct thermal_cooling_device pointer on success,
 664  * and NULL on failure.
 665  */
 666 struct thermal_cooling_device *
 667 of_cpufreq_cooling_register(struct cpufreq_policy *policy)
 668 {
 669         struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
 670         struct thermal_cooling_device *cdev = NULL;
 671
 672         if (!np) {
 673                 pr_err("cpufreq_cooling: OF node not available for cpu%d\n",
 674                        policy->cpu);
 675                 return NULL;
 676         }
 677
 678         if (of_find_property(np, "#cooling-cells", NULL)) {
 679                 struct em_perf_domain *em = em_cpu_get(policy->cpu);
 680
 681                 cdev = __cpufreq_cooling_register(np, policy, em);
 682                 if (IS_ERR(cdev)) {
 683                         pr_err("cpufreq_cooling: cpu%d failed to register as cooling device: %ld\n",
 684                                policy->cpu, PTR_ERR(cdev));
 685                         cdev = NULL;
 686                 }
 687         }
 688
 689         of_node_put(np);
 690         return cdev;
 691 }
 692 EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
 693
 694 /**
 695  * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
 696  * @cdev: thermal cooling device pointer.
 697  *
 698  * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
 699  */
 700 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
 701 {
 702         struct cpufreq_cooling_device *cpufreq_cdev;
 703
 704         if (!cdev)
 705                 return;
 706
 707         cpufreq_cdev = cdev->devdata;
 708
 709         mutex_lock(&cooling_list_lock);
 710         list_del(&cpufreq_cdev->node);
 711         mutex_unlock(&cooling_list_lock);
 712
 713         thermal_cooling_device_unregister(cdev);
 714         freq_qos_remove_request(&cpufreq_cdev->qos_req);
 715         ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id);
 716         free_idle_time(cpufreq_cdev);
 717         kfree(cpufreq_cdev);
 718 }
 719 EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);