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#include <linux/units.h>
25
26#include "thermal_trace.h"
27
28/*
29 * Cooling state <-> CPUFreq frequency
30 *
31 * Cooling states are translated to frequencies throughout this driver and this
32 * is the relation between them.
33 *
34 * Highest cooling state corresponds to lowest possible frequency.
35 *
36 * i.e.
37 * level 0 --> 1st Max Freq
38 * level 1 --> 2nd Max Freq
39 * ...
40 */
41
42/**
43 * struct time_in_idle - Idle time stats
44 * @time: previous reading of the absolute time that this cpu was idle
45 * @timestamp: wall time of the last invocation of get_cpu_idle_time_us()
46 */
47struct time_in_idle {
48 u64 time;
49 u64 timestamp;
50};
51
52/**
53 * struct cpufreq_cooling_device - data for cooling device with cpufreq
54 * @last_load: load measured by the latest call to cpufreq_get_requested_power()
55 * @cpufreq_state: integer value representing the current state of cpufreq
56 * cooling devices.
57 * @max_level: maximum cooling level. One less than total number of valid
58 * cpufreq frequencies.
59 * @em: Reference on the Energy Model of the device
60 * @policy: cpufreq policy.
61 * @cooling_ops: cpufreq callbacks to thermal cooling device ops
62 * @idle_time: idle time stats
63 * @qos_req: PM QoS contraint to apply
64 *
65 * This structure is required for keeping information of each registered
66 * cpufreq_cooling_device.
67 */
68struct cpufreq_cooling_device {
69 u32 last_load;
70 unsigned int cpufreq_state;
71 unsigned int max_level;
72 struct em_perf_domain *em;
73 struct cpufreq_policy *policy;
74 struct thermal_cooling_device_ops cooling_ops;
75#ifndef CONFIG_SMP
76 struct time_in_idle *idle_time;
77#endif
78 struct freq_qos_request qos_req;
79};
80
81#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
82/**
83 * get_level: Find the level for a particular frequency
84 * @cpufreq_cdev: cpufreq_cdev for which the property is required
85 * @freq: Frequency
86 *
87 * Return: level corresponding to the frequency.
88 */
89static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_cdev,
90 unsigned int freq)
91{
92 struct em_perf_state *table;
93 int i;
94
95 rcu_read_lock();
96 table = em_perf_state_from_pd(pd: cpufreq_cdev->em);
97 for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
98 if (freq > table[i].frequency)
99 break;
100 }
101 rcu_read_unlock();
102
103 return cpufreq_cdev->max_level - i - 1;
104}
105
106static u32 cpu_freq_to_power(struct cpufreq_cooling_device *cpufreq_cdev,
107 u32 freq)
108{
109 struct em_perf_state *table;
110 unsigned long power_mw;
111 int i;
112
113 rcu_read_lock();
114 table = em_perf_state_from_pd(pd: cpufreq_cdev->em);
115 for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
116 if (freq > table[i].frequency)
117 break;
118 }
119
120 power_mw = table[i + 1].power;
121 power_mw /= MICROWATT_PER_MILLIWATT;
122 rcu_read_unlock();
123
124 return power_mw;
125}
126
127static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
128 u32 power)
129{
130 struct em_perf_state *table;
131 unsigned long em_power_mw;
132 u32 freq;
133 int i;
134
135 rcu_read_lock();
136 table = em_perf_state_from_pd(pd: cpufreq_cdev->em);
137 for (i = cpufreq_cdev->max_level; i > 0; i--) {
138 /* Convert EM power to milli-Watts to make safe comparison */
139 em_power_mw = table[i].power;
140 em_power_mw /= MICROWATT_PER_MILLIWATT;
141 if (power >= em_power_mw)
142 break;
143 }
144 freq = table[i].frequency;
145 rcu_read_unlock();
146
147 return freq;
148}
149
150/**
151 * get_load() - get load for a cpu
152 * @cpufreq_cdev: struct cpufreq_cooling_device for the cpu
153 * @cpu: cpu number
154 * @cpu_idx: index of the cpu in time_in_idle array
155 *
156 * Return: The average load of cpu @cpu in percentage since this
157 * function was last called.
158 */
159#ifdef CONFIG_SMP
160static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
161 int cpu_idx)
162{
163 unsigned long util = sched_cpu_util(cpu);
164
165 return (util * 100) / arch_scale_cpu_capacity(cpu);
166}
167#else /* !CONFIG_SMP */
168static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
169 int cpu_idx)
170{
171 u32 load;
172 u64 now, now_idle, delta_time, delta_idle;
173 struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx];
174
175 now_idle = get_cpu_idle_time(cpu, &now, 0);
176 delta_idle = now_idle - idle_time->time;
177 delta_time = now - idle_time->timestamp;
178
179 if (delta_time <= delta_idle)
180 load = 0;
181 else
182 load = div64_u64(100 * (delta_time - delta_idle), delta_time);
183
184 idle_time->time = now_idle;
185 idle_time->timestamp = now;
186
187 return load;
188}
189#endif /* CONFIG_SMP */
190
191/**
192 * get_dynamic_power() - calculate the dynamic power
193 * @cpufreq_cdev: &cpufreq_cooling_device for this cdev
194 * @freq: current frequency
195 *
196 * Return: the dynamic power consumed by the cpus described by
197 * @cpufreq_cdev.
198 */
199static u32 get_dynamic_power(struct cpufreq_cooling_device *cpufreq_cdev,
200 unsigned long freq)
201{
202 u32 raw_cpu_power;
203
204 raw_cpu_power = cpu_freq_to_power(cpufreq_cdev, freq);
205 return (raw_cpu_power * cpufreq_cdev->last_load) / 100;
206}
207
208/**
209 * cpufreq_get_requested_power() - get the current power
210 * @cdev: &thermal_cooling_device pointer
211 * @power: pointer in which to store the resulting power
212 *
213 * Calculate the current power consumption of the cpus in milliwatts
214 * and store it in @power. This function should actually calculate
215 * the requested power, but it's hard to get the frequency that
216 * cpufreq would have assigned if there were no thermal limits.
217 * Instead, we calculate the current power on the assumption that the
218 * immediate future will look like the immediate past.
219 *
220 * We use the current frequency and the average load since this
221 * function was last called. In reality, there could have been
222 * multiple opps since this function was last called and that affects
223 * the load calculation. While it's not perfectly accurate, this
224 * simplification is good enough and works. REVISIT this, as more
225 * complex code may be needed if experiments show that it's not
226 * accurate enough.
227 *
228 * Return: 0 on success, this function doesn't fail.
229 */
230static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev,
231 u32 *power)
232{
233 unsigned long freq;
234 int i = 0, cpu;
235 u32 total_load = 0;
236 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
237 struct cpufreq_policy *policy = cpufreq_cdev->policy;
238
239 freq = cpufreq_quick_get(cpu: policy->cpu);
240
241 for_each_cpu(cpu, policy->related_cpus) {
242 u32 load;
243
244 if (cpu_online(cpu))
245 load = get_load(cpufreq_cdev, cpu, cpu_idx: i);
246 else
247 load = 0;
248
249 total_load += load;
250 }
251
252 cpufreq_cdev->last_load = total_load;
253
254 *power = get_dynamic_power(cpufreq_cdev, freq);
255
256 trace_thermal_power_cpu_get_power_simple(cpu: policy->cpu, power: *power);
257
258 return 0;
259}
260
261/**
262 * cpufreq_state2power() - convert a cpu cdev state to power consumed
263 * @cdev: &thermal_cooling_device pointer
264 * @state: cooling device state to be converted
265 * @power: pointer in which to store the resulting power
266 *
267 * Convert cooling device state @state into power consumption in
268 * milliwatts assuming 100% load. Store the calculated power in
269 * @power.
270 *
271 * Return: 0 on success, -EINVAL if the cooling device state is bigger
272 * than maximum allowed.
273 */
274static int cpufreq_state2power(struct thermal_cooling_device *cdev,
275 unsigned long state, u32 *power)
276{
277 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
278 unsigned int freq, num_cpus, idx;
279 struct em_perf_state *table;
280
281 /* Request state should be less than max_level */
282 if (state > cpufreq_cdev->max_level)
283 return -EINVAL;
284
285 num_cpus = cpumask_weight(srcp: cpufreq_cdev->policy->cpus);
286
287 idx = cpufreq_cdev->max_level - state;
288
289 rcu_read_lock();
290 table = em_perf_state_from_pd(pd: cpufreq_cdev->em);
291 freq = table[idx].frequency;
292 rcu_read_unlock();
293
294 *power = cpu_freq_to_power(cpufreq_cdev, freq) * num_cpus;
295
296 return 0;
297}
298
299/**
300 * cpufreq_power2state() - convert power to a cooling device state
301 * @cdev: &thermal_cooling_device pointer
302 * @power: power in milliwatts to be converted
303 * @state: pointer in which to store the resulting state
304 *
305 * Calculate a cooling device state for the cpus described by @cdev
306 * that would allow them to consume at most @power mW and store it in
307 * @state. Note that this calculation depends on external factors
308 * such as the CPUs load. Calling this function with the same power
309 * as input can yield different cooling device states depending on those
310 * external factors.
311 *
312 * Return: 0 on success, this function doesn't fail.
313 */
314static int cpufreq_power2state(struct thermal_cooling_device *cdev,
315 u32 power, unsigned long *state)
316{
317 unsigned int target_freq;
318 u32 last_load, normalised_power;
319 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
320 struct cpufreq_policy *policy = cpufreq_cdev->policy;
321
322 last_load = cpufreq_cdev->last_load ?: 1;
323 normalised_power = (power * 100) / last_load;
324 target_freq = cpu_power_to_freq(cpufreq_cdev, power: normalised_power);
325
326 *state = get_level(cpufreq_cdev, freq: target_freq);
327 trace_thermal_power_cpu_limit(cpus: policy->related_cpus, freq: target_freq, cdev_state: *state,
328 power);
329 return 0;
330}
331
332static inline bool em_is_sane(struct cpufreq_cooling_device *cpufreq_cdev,
333 struct em_perf_domain *em) {
334 struct cpufreq_policy *policy;
335 unsigned int nr_levels;
336
337 if (!em || em_is_artificial(em))
338 return false;
339
340 policy = cpufreq_cdev->policy;
341 if (!cpumask_equal(src1p: policy->related_cpus, em_span_cpus(em))) {
342 pr_err("The span of pd %*pbl is misaligned with cpufreq policy %*pbl\n",
343 cpumask_pr_args(em_span_cpus(em)),
344 cpumask_pr_args(policy->related_cpus));
345 return false;
346 }
347
348 nr_levels = cpufreq_cdev->max_level + 1;
349 if (em_pd_nr_perf_states(pd: em) != nr_levels) {
350 pr_err("The number of performance states in pd %*pbl (%u) doesn't match the number of cooling levels (%u)\n",
351 cpumask_pr_args(em_span_cpus(em)),
352 em_pd_nr_perf_states(em), nr_levels);
353 return false;
354 }
355
356 return true;
357}
358#endif /* CONFIG_THERMAL_GOV_POWER_ALLOCATOR */
359
360#ifdef CONFIG_SMP
361static inline int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
362{
363 return 0;
364}
365
366static inline void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
367{
368}
369#else
370static int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
371{
372 unsigned int num_cpus = cpumask_weight(cpufreq_cdev->policy->related_cpus);
373
374 cpufreq_cdev->idle_time = kcalloc(num_cpus,
375 sizeof(*cpufreq_cdev->idle_time),
376 GFP_KERNEL);
377 if (!cpufreq_cdev->idle_time)
378 return -ENOMEM;
379
380 return 0;
381}
382
383static void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
384{
385 kfree(cpufreq_cdev->idle_time);
386 cpufreq_cdev->idle_time = NULL;
387}
388#endif /* CONFIG_SMP */
389
390static unsigned int get_state_freq(struct cpufreq_cooling_device *cpufreq_cdev,
391 unsigned long state)
392{
393 struct cpufreq_policy *policy;
394 unsigned long idx;
395
396#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
397 /* Use the Energy Model table if available */
398 if (cpufreq_cdev->em) {
399 struct em_perf_state *table;
400 unsigned int freq;
401
402 idx = cpufreq_cdev->max_level - state;
403
404 rcu_read_lock();
405 table = em_perf_state_from_pd(pd: cpufreq_cdev->em);
406 freq = table[idx].frequency;
407 rcu_read_unlock();
408
409 return freq;
410 }
411#endif
412
413 /* Otherwise, fallback on the CPUFreq table */
414 policy = cpufreq_cdev->policy;
415 if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
416 idx = cpufreq_cdev->max_level - state;
417 else
418 idx = state;
419
420 return policy->freq_table[idx].frequency;
421}
422
423/* cpufreq cooling device callback functions are defined below */
424
425/**
426 * cpufreq_get_max_state - callback function to get the max cooling state.
427 * @cdev: thermal cooling device pointer.
428 * @state: fill this variable with the max cooling state.
429 *
430 * Callback for the thermal cooling device to return the cpufreq
431 * max cooling state.
432 *
433 * Return: 0 on success, this function doesn't fail.
434 */
435static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
436 unsigned long *state)
437{
438 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
439
440 *state = cpufreq_cdev->max_level;
441 return 0;
442}
443
444/**
445 * cpufreq_get_cur_state - callback function to get the current cooling state.
446 * @cdev: thermal cooling device pointer.
447 * @state: fill this variable with the current cooling state.
448 *
449 * Callback for the thermal cooling device to return the cpufreq
450 * current cooling state.
451 *
452 * Return: 0 on success, this function doesn't fail.
453 */
454static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
455 unsigned long *state)
456{
457 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
458
459 *state = cpufreq_cdev->cpufreq_state;
460
461 return 0;
462}
463
464/**
465 * cpufreq_set_cur_state - callback function to set the current cooling state.
466 * @cdev: thermal cooling device pointer.
467 * @state: set this variable to the current cooling state.
468 *
469 * Callback for the thermal cooling device to change the cpufreq
470 * current cooling state.
471 *
472 * Return: 0 on success, an error code otherwise.
473 */
474static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
475 unsigned long state)
476{
477 struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
478 unsigned int frequency;
479 int ret;
480
481 /* Request state should be less than max_level */
482 if (state > cpufreq_cdev->max_level)
483 return -EINVAL;
484
485 /* Check if the old cooling action is same as new cooling action */
486 if (cpufreq_cdev->cpufreq_state == state)
487 return 0;
488
489 frequency = get_state_freq(cpufreq_cdev, state);
490
491 ret = freq_qos_update_request(req: &cpufreq_cdev->qos_req, new_value: frequency);
492 if (ret >= 0) {
493 cpufreq_cdev->cpufreq_state = state;
494 ret = 0;
495 }
496
497 return ret;
498}
499
500/**
501 * __cpufreq_cooling_register - helper function to create cpufreq cooling device
502 * @np: a valid struct device_node to the cooling device tree node
503 * @policy: cpufreq policy
504 * Normally this should be same as cpufreq policy->related_cpus.
505 * @em: Energy Model of the cpufreq policy
506 *
507 * This interface function registers the cpufreq cooling device with the name
508 * "cpufreq-%s". This API can support multiple instances of cpufreq
509 * cooling devices. It also gives the opportunity to link the cooling device
510 * with a device tree node, in order to bind it via the thermal DT code.
511 *
512 * Return: a valid struct thermal_cooling_device pointer on success,
513 * on failure, it returns a corresponding ERR_PTR().
514 */
515static struct thermal_cooling_device *
516__cpufreq_cooling_register(struct device_node *np,
517 struct cpufreq_policy *policy,
518 struct em_perf_domain *em)
519{
520 struct thermal_cooling_device *cdev;
521 struct cpufreq_cooling_device *cpufreq_cdev;
522 unsigned int i;
523 struct device *dev;
524 int ret;
525 struct thermal_cooling_device_ops *cooling_ops;
526 char *name;
527
528 if (IS_ERR_OR_NULL(ptr: policy)) {
529 pr_err("%s: cpufreq policy isn't valid: %p\n", __func__, policy);
530 return ERR_PTR(error: -EINVAL);
531 }
532
533 dev = get_cpu_device(cpu: policy->cpu);
534 if (unlikely(!dev)) {
535 pr_warn("No cpu device for cpu %d\n", policy->cpu);
536 return ERR_PTR(error: -ENODEV);
537 }
538
539 i = cpufreq_table_count_valid_entries(policy);
540 if (!i) {
541 pr_debug("%s: CPUFreq table not found or has no valid entries\n",
542 __func__);
543 return ERR_PTR(error: -ENODEV);
544 }
545
546 cpufreq_cdev = kzalloc(sizeof(*cpufreq_cdev), GFP_KERNEL);
547 if (!cpufreq_cdev)
548 return ERR_PTR(error: -ENOMEM);
549
550 cpufreq_cdev->policy = policy;
551
552 ret = allocate_idle_time(cpufreq_cdev);
553 if (ret) {
554 cdev = ERR_PTR(error: ret);
555 goto free_cdev;
556 }
557
558 /* max_level is an index, not a counter */
559 cpufreq_cdev->max_level = i - 1;
560
561 cooling_ops = &cpufreq_cdev->cooling_ops;
562 cooling_ops->get_max_state = cpufreq_get_max_state;
563 cooling_ops->get_cur_state = cpufreq_get_cur_state;
564 cooling_ops->set_cur_state = cpufreq_set_cur_state;
565
566#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
567 if (em_is_sane(cpufreq_cdev, em)) {
568 cpufreq_cdev->em = em;
569 cooling_ops->get_requested_power = cpufreq_get_requested_power;
570 cooling_ops->state2power = cpufreq_state2power;
571 cooling_ops->power2state = cpufreq_power2state;
572 } else
573#endif
574 if (policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED) {
575 pr_err("%s: unsorted frequency tables are not supported\n",
576 __func__);
577 cdev = ERR_PTR(error: -EINVAL);
578 goto free_idle_time;
579 }
580
581 ret = freq_qos_add_request(qos: &policy->constraints,
582 req: &cpufreq_cdev->qos_req, type: FREQ_QOS_MAX,
583 value: get_state_freq(cpufreq_cdev, state: 0));
584 if (ret < 0) {
585 pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
586 ret);
587 cdev = ERR_PTR(error: ret);
588 goto free_idle_time;
589 }
590
591 cdev = ERR_PTR(error: -ENOMEM);
592 name = kasprintf(GFP_KERNEL, fmt: "cpufreq-%s", dev_name(dev));
593 if (!name)
594 goto remove_qos_req;
595
596 cdev = thermal_of_cooling_device_register(np, name, cpufreq_cdev,
597 cooling_ops);
598 kfree(objp: name);
599
600 if (IS_ERR(ptr: cdev))
601 goto remove_qos_req;
602
603 return cdev;
604
605remove_qos_req:
606 freq_qos_remove_request(req: &cpufreq_cdev->qos_req);
607free_idle_time:
608 free_idle_time(cpufreq_cdev);
609free_cdev:
610 kfree(objp: cpufreq_cdev);
611 return cdev;
612}
613
614/**
615 * cpufreq_cooling_register - function to create cpufreq cooling device.
616 * @policy: cpufreq policy
617 *
618 * This interface function registers the cpufreq cooling device with the name
619 * "cpufreq-%s". This API can support multiple instances of cpufreq cooling
620 * devices.
621 *
622 * Return: a valid struct thermal_cooling_device pointer on success,
623 * on failure, it returns a corresponding ERR_PTR().
624 */
625struct thermal_cooling_device *
626cpufreq_cooling_register(struct cpufreq_policy *policy)
627{
628 return __cpufreq_cooling_register(NULL, policy, NULL);
629}
630EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
631
632/**
633 * of_cpufreq_cooling_register - function to create cpufreq cooling device.
634 * @policy: cpufreq policy
635 *
636 * This interface function registers the cpufreq cooling device with the name
637 * "cpufreq-%s". This API can support multiple instances of cpufreq cooling
638 * devices. Using this API, the cpufreq cooling device will be linked to the
639 * device tree node provided.
640 *
641 * Using this function, the cooling device will implement the power
642 * extensions by using the Energy Model (if present). The cpus must have
643 * registered their OPPs using the OPP library.
644 *
645 * Return: a valid struct thermal_cooling_device pointer on success,
646 * and NULL on failure.
647 */
648struct thermal_cooling_device *
649of_cpufreq_cooling_register(struct cpufreq_policy *policy)
650{
651 struct device_node *np = of_get_cpu_node(cpu: policy->cpu, NULL);
652 struct thermal_cooling_device *cdev = NULL;
653
654 if (!np) {
655 pr_err("cpufreq_cooling: OF node not available for cpu%d\n",
656 policy->cpu);
657 return NULL;
658 }
659
660 if (of_property_present(np, propname: "#cooling-cells")) {
661 struct em_perf_domain *em = em_cpu_get(cpu: policy->cpu);
662
663 cdev = __cpufreq_cooling_register(np, policy, em);
664 if (IS_ERR(ptr: cdev)) {
665 pr_err("cpufreq_cooling: cpu%d failed to register as cooling device: %ld\n",
666 policy->cpu, PTR_ERR(cdev));
667 cdev = NULL;
668 }
669 }
670
671 of_node_put(node: np);
672 return cdev;
673}
674EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
675
676/**
677 * cpufreq_cooling_unregister - function to remove cpufreq cooling device.
678 * @cdev: thermal cooling device pointer.
679 *
680 * This interface function unregisters the "cpufreq-%x" cooling device.
681 */
682void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
683{
684 struct cpufreq_cooling_device *cpufreq_cdev;
685
686 if (!cdev)
687 return;
688
689 cpufreq_cdev = cdev->devdata;
690
691 thermal_cooling_device_unregister(cdev);
692 freq_qos_remove_request(req: &cpufreq_cdev->qos_req);
693 free_idle_time(cpufreq_cdev);
694 kfree(objp: cpufreq_cdev);
695}
696EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
697

source code of linux/drivers/thermal/cpufreq_cooling.c