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