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