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