xref: /openbmc/linux/drivers/cpufreq/cpufreq.c (revision 7f904d7e1f3ec7c2de47c024a5a5c30988b54703)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/drivers/cpufreq/cpufreq.c
4  *
5  *  Copyright (C) 2001 Russell King
6  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7  *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8  *
9  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
10  *	Added handling for CPU hotplug
11  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
12  *	Fix handling for CPU hotplug -- affected CPUs
13  */
14 
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 
17 #include <linux/cpu.h>
18 #include <linux/cpufreq.h>
19 #include <linux/cpu_cooling.h>
20 #include <linux/delay.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/kernel_stat.h>
24 #include <linux/module.h>
25 #include <linux/mutex.h>
26 #include <linux/slab.h>
27 #include <linux/suspend.h>
28 #include <linux/syscore_ops.h>
29 #include <linux/tick.h>
30 #include <trace/events/power.h>
31 
32 static LIST_HEAD(cpufreq_policy_list);
33 
34 /* Macros to iterate over CPU policies */
35 #define for_each_suitable_policy(__policy, __active)			 \
36 	list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
37 		if ((__active) == !policy_is_inactive(__policy))
38 
39 #define for_each_active_policy(__policy)		\
40 	for_each_suitable_policy(__policy, true)
41 #define for_each_inactive_policy(__policy)		\
42 	for_each_suitable_policy(__policy, false)
43 
44 #define for_each_policy(__policy)			\
45 	list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
46 
47 /* Iterate over governors */
48 static LIST_HEAD(cpufreq_governor_list);
49 #define for_each_governor(__governor)				\
50 	list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
51 
52 /**
53  * The "cpufreq driver" - the arch- or hardware-dependent low
54  * level driver of CPUFreq support, and its spinlock. This lock
55  * also protects the cpufreq_cpu_data array.
56  */
57 static struct cpufreq_driver *cpufreq_driver;
58 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
59 static DEFINE_RWLOCK(cpufreq_driver_lock);
60 
61 /* Flag to suspend/resume CPUFreq governors */
62 static bool cpufreq_suspended;
63 
64 static inline bool has_target(void)
65 {
66 	return cpufreq_driver->target_index || cpufreq_driver->target;
67 }
68 
69 /* internal prototypes */
70 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
71 static int cpufreq_init_governor(struct cpufreq_policy *policy);
72 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
73 static int cpufreq_start_governor(struct cpufreq_policy *policy);
74 static void cpufreq_stop_governor(struct cpufreq_policy *policy);
75 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
76 
77 /**
78  * Two notifier lists: the "policy" list is involved in the
79  * validation process for a new CPU frequency policy; the
80  * "transition" list for kernel code that needs to handle
81  * changes to devices when the CPU clock speed changes.
82  * The mutex locks both lists.
83  */
84 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
85 SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
86 
87 static int off __read_mostly;
88 static int cpufreq_disabled(void)
89 {
90 	return off;
91 }
92 void disable_cpufreq(void)
93 {
94 	off = 1;
95 }
96 static DEFINE_MUTEX(cpufreq_governor_mutex);
97 
98 bool have_governor_per_policy(void)
99 {
100 	return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
101 }
102 EXPORT_SYMBOL_GPL(have_governor_per_policy);
103 
104 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
105 {
106 	if (have_governor_per_policy())
107 		return &policy->kobj;
108 	else
109 		return cpufreq_global_kobject;
110 }
111 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
112 
113 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
114 {
115 	u64 idle_time;
116 	u64 cur_wall_time;
117 	u64 busy_time;
118 
119 	cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
120 
121 	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
122 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
123 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
124 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
125 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
126 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
127 
128 	idle_time = cur_wall_time - busy_time;
129 	if (wall)
130 		*wall = div_u64(cur_wall_time, NSEC_PER_USEC);
131 
132 	return div_u64(idle_time, NSEC_PER_USEC);
133 }
134 
135 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
136 {
137 	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
138 
139 	if (idle_time == -1ULL)
140 		return get_cpu_idle_time_jiffy(cpu, wall);
141 	else if (!io_busy)
142 		idle_time += get_cpu_iowait_time_us(cpu, wall);
143 
144 	return idle_time;
145 }
146 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
147 
148 __weak void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
149 		unsigned long max_freq)
150 {
151 }
152 EXPORT_SYMBOL_GPL(arch_set_freq_scale);
153 
154 /*
155  * This is a generic cpufreq init() routine which can be used by cpufreq
156  * drivers of SMP systems. It will do following:
157  * - validate & show freq table passed
158  * - set policies transition latency
159  * - policy->cpus with all possible CPUs
160  */
161 int cpufreq_generic_init(struct cpufreq_policy *policy,
162 		struct cpufreq_frequency_table *table,
163 		unsigned int transition_latency)
164 {
165 	policy->freq_table = table;
166 	policy->cpuinfo.transition_latency = transition_latency;
167 
168 	/*
169 	 * The driver only supports the SMP configuration where all processors
170 	 * share the clock and voltage and clock.
171 	 */
172 	cpumask_setall(policy->cpus);
173 
174 	return 0;
175 }
176 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
177 
178 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
179 {
180 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
181 
182 	return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
183 }
184 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
185 
186 unsigned int cpufreq_generic_get(unsigned int cpu)
187 {
188 	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
189 
190 	if (!policy || IS_ERR(policy->clk)) {
191 		pr_err("%s: No %s associated to cpu: %d\n",
192 		       __func__, policy ? "clk" : "policy", cpu);
193 		return 0;
194 	}
195 
196 	return clk_get_rate(policy->clk) / 1000;
197 }
198 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
199 
200 /**
201  * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
202  * @cpu: CPU to find the policy for.
203  *
204  * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
205  * the kobject reference counter of that policy.  Return a valid policy on
206  * success or NULL on failure.
207  *
208  * The policy returned by this function has to be released with the help of
209  * cpufreq_cpu_put() to balance its kobject reference counter properly.
210  */
211 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
212 {
213 	struct cpufreq_policy *policy = NULL;
214 	unsigned long flags;
215 
216 	if (WARN_ON(cpu >= nr_cpu_ids))
217 		return NULL;
218 
219 	/* get the cpufreq driver */
220 	read_lock_irqsave(&cpufreq_driver_lock, flags);
221 
222 	if (cpufreq_driver) {
223 		/* get the CPU */
224 		policy = cpufreq_cpu_get_raw(cpu);
225 		if (policy)
226 			kobject_get(&policy->kobj);
227 	}
228 
229 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
230 
231 	return policy;
232 }
233 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
234 
235 /**
236  * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
237  * @policy: cpufreq policy returned by cpufreq_cpu_get().
238  */
239 void cpufreq_cpu_put(struct cpufreq_policy *policy)
240 {
241 	kobject_put(&policy->kobj);
242 }
243 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
244 
245 /**
246  * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
247  * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
248  */
249 void cpufreq_cpu_release(struct cpufreq_policy *policy)
250 {
251 	if (WARN_ON(!policy))
252 		return;
253 
254 	lockdep_assert_held(&policy->rwsem);
255 
256 	up_write(&policy->rwsem);
257 
258 	cpufreq_cpu_put(policy);
259 }
260 
261 /**
262  * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
263  * @cpu: CPU to find the policy for.
264  *
265  * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
266  * if the policy returned by it is not NULL, acquire its rwsem for writing.
267  * Return the policy if it is active or release it and return NULL otherwise.
268  *
269  * The policy returned by this function has to be released with the help of
270  * cpufreq_cpu_release() in order to release its rwsem and balance its usage
271  * counter properly.
272  */
273 struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
274 {
275 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
276 
277 	if (!policy)
278 		return NULL;
279 
280 	down_write(&policy->rwsem);
281 
282 	if (policy_is_inactive(policy)) {
283 		cpufreq_cpu_release(policy);
284 		return NULL;
285 	}
286 
287 	return policy;
288 }
289 
290 /*********************************************************************
291  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
292  *********************************************************************/
293 
294 /**
295  * adjust_jiffies - adjust the system "loops_per_jiffy"
296  *
297  * This function alters the system "loops_per_jiffy" for the clock
298  * speed change. Note that loops_per_jiffy cannot be updated on SMP
299  * systems as each CPU might be scaled differently. So, use the arch
300  * per-CPU loops_per_jiffy value wherever possible.
301  */
302 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
303 {
304 #ifndef CONFIG_SMP
305 	static unsigned long l_p_j_ref;
306 	static unsigned int l_p_j_ref_freq;
307 
308 	if (ci->flags & CPUFREQ_CONST_LOOPS)
309 		return;
310 
311 	if (!l_p_j_ref_freq) {
312 		l_p_j_ref = loops_per_jiffy;
313 		l_p_j_ref_freq = ci->old;
314 		pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
315 			 l_p_j_ref, l_p_j_ref_freq);
316 	}
317 	if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
318 		loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
319 								ci->new);
320 		pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
321 			 loops_per_jiffy, ci->new);
322 	}
323 #endif
324 }
325 
326 /**
327  * cpufreq_notify_transition - Notify frequency transition and adjust_jiffies.
328  * @policy: cpufreq policy to enable fast frequency switching for.
329  * @freqs: contain details of the frequency update.
330  * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
331  *
332  * This function calls the transition notifiers and the "adjust_jiffies"
333  * function. It is called twice on all CPU frequency changes that have
334  * external effects.
335  */
336 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
337 				      struct cpufreq_freqs *freqs,
338 				      unsigned int state)
339 {
340 	int cpu;
341 
342 	BUG_ON(irqs_disabled());
343 
344 	if (cpufreq_disabled())
345 		return;
346 
347 	freqs->policy = policy;
348 	freqs->flags = cpufreq_driver->flags;
349 	pr_debug("notification %u of frequency transition to %u kHz\n",
350 		 state, freqs->new);
351 
352 	switch (state) {
353 	case CPUFREQ_PRECHANGE:
354 		/*
355 		 * Detect if the driver reported a value as "old frequency"
356 		 * which is not equal to what the cpufreq core thinks is
357 		 * "old frequency".
358 		 */
359 		if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
360 			if (policy->cur && (policy->cur != freqs->old)) {
361 				pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
362 					 freqs->old, policy->cur);
363 				freqs->old = policy->cur;
364 			}
365 		}
366 
367 		srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
368 					 CPUFREQ_PRECHANGE, freqs);
369 
370 		adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
371 		break;
372 
373 	case CPUFREQ_POSTCHANGE:
374 		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
375 		pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
376 			 cpumask_pr_args(policy->cpus));
377 
378 		for_each_cpu(cpu, policy->cpus)
379 			trace_cpu_frequency(freqs->new, cpu);
380 
381 		srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
382 					 CPUFREQ_POSTCHANGE, freqs);
383 
384 		cpufreq_stats_record_transition(policy, freqs->new);
385 		policy->cur = freqs->new;
386 	}
387 }
388 
389 /* Do post notifications when there are chances that transition has failed */
390 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
391 		struct cpufreq_freqs *freqs, int transition_failed)
392 {
393 	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
394 	if (!transition_failed)
395 		return;
396 
397 	swap(freqs->old, freqs->new);
398 	cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
399 	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
400 }
401 
402 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
403 		struct cpufreq_freqs *freqs)
404 {
405 
406 	/*
407 	 * Catch double invocations of _begin() which lead to self-deadlock.
408 	 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
409 	 * doesn't invoke _begin() on their behalf, and hence the chances of
410 	 * double invocations are very low. Moreover, there are scenarios
411 	 * where these checks can emit false-positive warnings in these
412 	 * drivers; so we avoid that by skipping them altogether.
413 	 */
414 	WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
415 				&& current == policy->transition_task);
416 
417 wait:
418 	wait_event(policy->transition_wait, !policy->transition_ongoing);
419 
420 	spin_lock(&policy->transition_lock);
421 
422 	if (unlikely(policy->transition_ongoing)) {
423 		spin_unlock(&policy->transition_lock);
424 		goto wait;
425 	}
426 
427 	policy->transition_ongoing = true;
428 	policy->transition_task = current;
429 
430 	spin_unlock(&policy->transition_lock);
431 
432 	cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
433 }
434 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
435 
436 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
437 		struct cpufreq_freqs *freqs, int transition_failed)
438 {
439 	if (WARN_ON(!policy->transition_ongoing))
440 		return;
441 
442 	cpufreq_notify_post_transition(policy, freqs, transition_failed);
443 
444 	policy->transition_ongoing = false;
445 	policy->transition_task = NULL;
446 
447 	wake_up(&policy->transition_wait);
448 }
449 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
450 
451 /*
452  * Fast frequency switching status count.  Positive means "enabled", negative
453  * means "disabled" and 0 means "not decided yet".
454  */
455 static int cpufreq_fast_switch_count;
456 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
457 
458 static void cpufreq_list_transition_notifiers(void)
459 {
460 	struct notifier_block *nb;
461 
462 	pr_info("Registered transition notifiers:\n");
463 
464 	mutex_lock(&cpufreq_transition_notifier_list.mutex);
465 
466 	for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
467 		pr_info("%pS\n", nb->notifier_call);
468 
469 	mutex_unlock(&cpufreq_transition_notifier_list.mutex);
470 }
471 
472 /**
473  * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
474  * @policy: cpufreq policy to enable fast frequency switching for.
475  *
476  * Try to enable fast frequency switching for @policy.
477  *
478  * The attempt will fail if there is at least one transition notifier registered
479  * at this point, as fast frequency switching is quite fundamentally at odds
480  * with transition notifiers.  Thus if successful, it will make registration of
481  * transition notifiers fail going forward.
482  */
483 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
484 {
485 	lockdep_assert_held(&policy->rwsem);
486 
487 	if (!policy->fast_switch_possible)
488 		return;
489 
490 	mutex_lock(&cpufreq_fast_switch_lock);
491 	if (cpufreq_fast_switch_count >= 0) {
492 		cpufreq_fast_switch_count++;
493 		policy->fast_switch_enabled = true;
494 	} else {
495 		pr_warn("CPU%u: Fast frequency switching not enabled\n",
496 			policy->cpu);
497 		cpufreq_list_transition_notifiers();
498 	}
499 	mutex_unlock(&cpufreq_fast_switch_lock);
500 }
501 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
502 
503 /**
504  * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
505  * @policy: cpufreq policy to disable fast frequency switching for.
506  */
507 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
508 {
509 	mutex_lock(&cpufreq_fast_switch_lock);
510 	if (policy->fast_switch_enabled) {
511 		policy->fast_switch_enabled = false;
512 		if (!WARN_ON(cpufreq_fast_switch_count <= 0))
513 			cpufreq_fast_switch_count--;
514 	}
515 	mutex_unlock(&cpufreq_fast_switch_lock);
516 }
517 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
518 
519 /**
520  * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
521  * one.
522  * @target_freq: target frequency to resolve.
523  *
524  * The target to driver frequency mapping is cached in the policy.
525  *
526  * Return: Lowest driver-supported frequency greater than or equal to the
527  * given target_freq, subject to policy (min/max) and driver limitations.
528  */
529 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
530 					 unsigned int target_freq)
531 {
532 	target_freq = clamp_val(target_freq, policy->min, policy->max);
533 	policy->cached_target_freq = target_freq;
534 
535 	if (cpufreq_driver->target_index) {
536 		int idx;
537 
538 		idx = cpufreq_frequency_table_target(policy, target_freq,
539 						     CPUFREQ_RELATION_L);
540 		policy->cached_resolved_idx = idx;
541 		return policy->freq_table[idx].frequency;
542 	}
543 
544 	if (cpufreq_driver->resolve_freq)
545 		return cpufreq_driver->resolve_freq(policy, target_freq);
546 
547 	return target_freq;
548 }
549 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
550 
551 unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
552 {
553 	unsigned int latency;
554 
555 	if (policy->transition_delay_us)
556 		return policy->transition_delay_us;
557 
558 	latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
559 	if (latency) {
560 		/*
561 		 * For platforms that can change the frequency very fast (< 10
562 		 * us), the above formula gives a decent transition delay. But
563 		 * for platforms where transition_latency is in milliseconds, it
564 		 * ends up giving unrealistic values.
565 		 *
566 		 * Cap the default transition delay to 10 ms, which seems to be
567 		 * a reasonable amount of time after which we should reevaluate
568 		 * the frequency.
569 		 */
570 		return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
571 	}
572 
573 	return LATENCY_MULTIPLIER;
574 }
575 EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
576 
577 /*********************************************************************
578  *                          SYSFS INTERFACE                          *
579  *********************************************************************/
580 static ssize_t show_boost(struct kobject *kobj,
581 			  struct kobj_attribute *attr, char *buf)
582 {
583 	return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
584 }
585 
586 static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
587 			   const char *buf, size_t count)
588 {
589 	int ret, enable;
590 
591 	ret = sscanf(buf, "%d", &enable);
592 	if (ret != 1 || enable < 0 || enable > 1)
593 		return -EINVAL;
594 
595 	if (cpufreq_boost_trigger_state(enable)) {
596 		pr_err("%s: Cannot %s BOOST!\n",
597 		       __func__, enable ? "enable" : "disable");
598 		return -EINVAL;
599 	}
600 
601 	pr_debug("%s: cpufreq BOOST %s\n",
602 		 __func__, enable ? "enabled" : "disabled");
603 
604 	return count;
605 }
606 define_one_global_rw(boost);
607 
608 static struct cpufreq_governor *find_governor(const char *str_governor)
609 {
610 	struct cpufreq_governor *t;
611 
612 	for_each_governor(t)
613 		if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
614 			return t;
615 
616 	return NULL;
617 }
618 
619 static int cpufreq_parse_policy(char *str_governor,
620 				struct cpufreq_policy *policy)
621 {
622 	if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
623 		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
624 		return 0;
625 	}
626 	if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
627 		policy->policy = CPUFREQ_POLICY_POWERSAVE;
628 		return 0;
629 	}
630 	return -EINVAL;
631 }
632 
633 /**
634  * cpufreq_parse_governor - parse a governor string only for !setpolicy
635  */
636 static int cpufreq_parse_governor(char *str_governor,
637 				  struct cpufreq_policy *policy)
638 {
639 	struct cpufreq_governor *t;
640 
641 	mutex_lock(&cpufreq_governor_mutex);
642 
643 	t = find_governor(str_governor);
644 	if (!t) {
645 		int ret;
646 
647 		mutex_unlock(&cpufreq_governor_mutex);
648 
649 		ret = request_module("cpufreq_%s", str_governor);
650 		if (ret)
651 			return -EINVAL;
652 
653 		mutex_lock(&cpufreq_governor_mutex);
654 
655 		t = find_governor(str_governor);
656 	}
657 	if (t && !try_module_get(t->owner))
658 		t = NULL;
659 
660 	mutex_unlock(&cpufreq_governor_mutex);
661 
662 	if (t) {
663 		policy->governor = t;
664 		return 0;
665 	}
666 
667 	return -EINVAL;
668 }
669 
670 /**
671  * cpufreq_per_cpu_attr_read() / show_##file_name() -
672  * print out cpufreq information
673  *
674  * Write out information from cpufreq_driver->policy[cpu]; object must be
675  * "unsigned int".
676  */
677 
678 #define show_one(file_name, object)			\
679 static ssize_t show_##file_name				\
680 (struct cpufreq_policy *policy, char *buf)		\
681 {							\
682 	return sprintf(buf, "%u\n", policy->object);	\
683 }
684 
685 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
686 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
687 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
688 show_one(scaling_min_freq, min);
689 show_one(scaling_max_freq, max);
690 
691 __weak unsigned int arch_freq_get_on_cpu(int cpu)
692 {
693 	return 0;
694 }
695 
696 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
697 {
698 	ssize_t ret;
699 	unsigned int freq;
700 
701 	freq = arch_freq_get_on_cpu(policy->cpu);
702 	if (freq)
703 		ret = sprintf(buf, "%u\n", freq);
704 	else if (cpufreq_driver && cpufreq_driver->setpolicy &&
705 			cpufreq_driver->get)
706 		ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
707 	else
708 		ret = sprintf(buf, "%u\n", policy->cur);
709 	return ret;
710 }
711 
712 /**
713  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
714  */
715 #define store_one(file_name, object)			\
716 static ssize_t store_##file_name					\
717 (struct cpufreq_policy *policy, const char *buf, size_t count)		\
718 {									\
719 	int ret, temp;							\
720 	struct cpufreq_policy new_policy;				\
721 									\
722 	memcpy(&new_policy, policy, sizeof(*policy));			\
723 	new_policy.min = policy->user_policy.min;			\
724 	new_policy.max = policy->user_policy.max;			\
725 									\
726 	ret = sscanf(buf, "%u", &new_policy.object);			\
727 	if (ret != 1)							\
728 		return -EINVAL;						\
729 									\
730 	temp = new_policy.object;					\
731 	ret = cpufreq_set_policy(policy, &new_policy);		\
732 	if (!ret)							\
733 		policy->user_policy.object = temp;			\
734 									\
735 	return ret ? ret : count;					\
736 }
737 
738 store_one(scaling_min_freq, min);
739 store_one(scaling_max_freq, max);
740 
741 /**
742  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
743  */
744 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
745 					char *buf)
746 {
747 	unsigned int cur_freq = __cpufreq_get(policy);
748 
749 	if (cur_freq)
750 		return sprintf(buf, "%u\n", cur_freq);
751 
752 	return sprintf(buf, "<unknown>\n");
753 }
754 
755 /**
756  * show_scaling_governor - show the current policy for the specified CPU
757  */
758 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
759 {
760 	if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
761 		return sprintf(buf, "powersave\n");
762 	else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
763 		return sprintf(buf, "performance\n");
764 	else if (policy->governor)
765 		return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
766 				policy->governor->name);
767 	return -EINVAL;
768 }
769 
770 /**
771  * store_scaling_governor - store policy for the specified CPU
772  */
773 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
774 					const char *buf, size_t count)
775 {
776 	int ret;
777 	char	str_governor[16];
778 	struct cpufreq_policy new_policy;
779 
780 	memcpy(&new_policy, policy, sizeof(*policy));
781 
782 	ret = sscanf(buf, "%15s", str_governor);
783 	if (ret != 1)
784 		return -EINVAL;
785 
786 	if (cpufreq_driver->setpolicy) {
787 		if (cpufreq_parse_policy(str_governor, &new_policy))
788 			return -EINVAL;
789 	} else {
790 		if (cpufreq_parse_governor(str_governor, &new_policy))
791 			return -EINVAL;
792 	}
793 
794 	ret = cpufreq_set_policy(policy, &new_policy);
795 
796 	if (new_policy.governor)
797 		module_put(new_policy.governor->owner);
798 
799 	return ret ? ret : count;
800 }
801 
802 /**
803  * show_scaling_driver - show the cpufreq driver currently loaded
804  */
805 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
806 {
807 	return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
808 }
809 
810 /**
811  * show_scaling_available_governors - show the available CPUfreq governors
812  */
813 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
814 						char *buf)
815 {
816 	ssize_t i = 0;
817 	struct cpufreq_governor *t;
818 
819 	if (!has_target()) {
820 		i += sprintf(buf, "performance powersave");
821 		goto out;
822 	}
823 
824 	for_each_governor(t) {
825 		if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
826 		    - (CPUFREQ_NAME_LEN + 2)))
827 			goto out;
828 		i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
829 	}
830 out:
831 	i += sprintf(&buf[i], "\n");
832 	return i;
833 }
834 
835 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
836 {
837 	ssize_t i = 0;
838 	unsigned int cpu;
839 
840 	for_each_cpu(cpu, mask) {
841 		if (i)
842 			i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
843 		i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
844 		if (i >= (PAGE_SIZE - 5))
845 			break;
846 	}
847 	i += sprintf(&buf[i], "\n");
848 	return i;
849 }
850 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
851 
852 /**
853  * show_related_cpus - show the CPUs affected by each transition even if
854  * hw coordination is in use
855  */
856 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
857 {
858 	return cpufreq_show_cpus(policy->related_cpus, buf);
859 }
860 
861 /**
862  * show_affected_cpus - show the CPUs affected by each transition
863  */
864 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
865 {
866 	return cpufreq_show_cpus(policy->cpus, buf);
867 }
868 
869 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
870 					const char *buf, size_t count)
871 {
872 	unsigned int freq = 0;
873 	unsigned int ret;
874 
875 	if (!policy->governor || !policy->governor->store_setspeed)
876 		return -EINVAL;
877 
878 	ret = sscanf(buf, "%u", &freq);
879 	if (ret != 1)
880 		return -EINVAL;
881 
882 	policy->governor->store_setspeed(policy, freq);
883 
884 	return count;
885 }
886 
887 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
888 {
889 	if (!policy->governor || !policy->governor->show_setspeed)
890 		return sprintf(buf, "<unsupported>\n");
891 
892 	return policy->governor->show_setspeed(policy, buf);
893 }
894 
895 /**
896  * show_bios_limit - show the current cpufreq HW/BIOS limitation
897  */
898 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
899 {
900 	unsigned int limit;
901 	int ret;
902 	ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
903 	if (!ret)
904 		return sprintf(buf, "%u\n", limit);
905 	return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
906 }
907 
908 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
909 cpufreq_freq_attr_ro(cpuinfo_min_freq);
910 cpufreq_freq_attr_ro(cpuinfo_max_freq);
911 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
912 cpufreq_freq_attr_ro(scaling_available_governors);
913 cpufreq_freq_attr_ro(scaling_driver);
914 cpufreq_freq_attr_ro(scaling_cur_freq);
915 cpufreq_freq_attr_ro(bios_limit);
916 cpufreq_freq_attr_ro(related_cpus);
917 cpufreq_freq_attr_ro(affected_cpus);
918 cpufreq_freq_attr_rw(scaling_min_freq);
919 cpufreq_freq_attr_rw(scaling_max_freq);
920 cpufreq_freq_attr_rw(scaling_governor);
921 cpufreq_freq_attr_rw(scaling_setspeed);
922 
923 static struct attribute *default_attrs[] = {
924 	&cpuinfo_min_freq.attr,
925 	&cpuinfo_max_freq.attr,
926 	&cpuinfo_transition_latency.attr,
927 	&scaling_min_freq.attr,
928 	&scaling_max_freq.attr,
929 	&affected_cpus.attr,
930 	&related_cpus.attr,
931 	&scaling_governor.attr,
932 	&scaling_driver.attr,
933 	&scaling_available_governors.attr,
934 	&scaling_setspeed.attr,
935 	NULL
936 };
937 
938 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
939 #define to_attr(a) container_of(a, struct freq_attr, attr)
940 
941 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
942 {
943 	struct cpufreq_policy *policy = to_policy(kobj);
944 	struct freq_attr *fattr = to_attr(attr);
945 	ssize_t ret;
946 
947 	down_read(&policy->rwsem);
948 	ret = fattr->show(policy, buf);
949 	up_read(&policy->rwsem);
950 
951 	return ret;
952 }
953 
954 static ssize_t store(struct kobject *kobj, struct attribute *attr,
955 		     const char *buf, size_t count)
956 {
957 	struct cpufreq_policy *policy = to_policy(kobj);
958 	struct freq_attr *fattr = to_attr(attr);
959 	ssize_t ret = -EINVAL;
960 
961 	/*
962 	 * cpus_read_trylock() is used here to work around a circular lock
963 	 * dependency problem with respect to the cpufreq_register_driver().
964 	 */
965 	if (!cpus_read_trylock())
966 		return -EBUSY;
967 
968 	if (cpu_online(policy->cpu)) {
969 		down_write(&policy->rwsem);
970 		ret = fattr->store(policy, buf, count);
971 		up_write(&policy->rwsem);
972 	}
973 
974 	cpus_read_unlock();
975 
976 	return ret;
977 }
978 
979 static void cpufreq_sysfs_release(struct kobject *kobj)
980 {
981 	struct cpufreq_policy *policy = to_policy(kobj);
982 	pr_debug("last reference is dropped\n");
983 	complete(&policy->kobj_unregister);
984 }
985 
986 static const struct sysfs_ops sysfs_ops = {
987 	.show	= show,
988 	.store	= store,
989 };
990 
991 static struct kobj_type ktype_cpufreq = {
992 	.sysfs_ops	= &sysfs_ops,
993 	.default_attrs	= default_attrs,
994 	.release	= cpufreq_sysfs_release,
995 };
996 
997 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
998 {
999 	struct device *dev = get_cpu_device(cpu);
1000 
1001 	if (!dev)
1002 		return;
1003 
1004 	if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1005 		return;
1006 
1007 	dev_dbg(dev, "%s: Adding symlink\n", __func__);
1008 	if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1009 		dev_err(dev, "cpufreq symlink creation failed\n");
1010 }
1011 
1012 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
1013 				   struct device *dev)
1014 {
1015 	dev_dbg(dev, "%s: Removing symlink\n", __func__);
1016 	sysfs_remove_link(&dev->kobj, "cpufreq");
1017 }
1018 
1019 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1020 {
1021 	struct freq_attr **drv_attr;
1022 	int ret = 0;
1023 
1024 	/* set up files for this cpu device */
1025 	drv_attr = cpufreq_driver->attr;
1026 	while (drv_attr && *drv_attr) {
1027 		ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1028 		if (ret)
1029 			return ret;
1030 		drv_attr++;
1031 	}
1032 	if (cpufreq_driver->get) {
1033 		ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1034 		if (ret)
1035 			return ret;
1036 	}
1037 
1038 	ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1039 	if (ret)
1040 		return ret;
1041 
1042 	if (cpufreq_driver->bios_limit) {
1043 		ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1044 		if (ret)
1045 			return ret;
1046 	}
1047 
1048 	return 0;
1049 }
1050 
1051 __weak struct cpufreq_governor *cpufreq_default_governor(void)
1052 {
1053 	return NULL;
1054 }
1055 
1056 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1057 {
1058 	struct cpufreq_governor *gov = NULL, *def_gov = NULL;
1059 	struct cpufreq_policy new_policy;
1060 
1061 	memcpy(&new_policy, policy, sizeof(*policy));
1062 
1063 	def_gov = cpufreq_default_governor();
1064 
1065 	if (has_target()) {
1066 		/*
1067 		 * Update governor of new_policy to the governor used before
1068 		 * hotplug
1069 		 */
1070 		gov = find_governor(policy->last_governor);
1071 		if (gov) {
1072 			pr_debug("Restoring governor %s for cpu %d\n",
1073 				policy->governor->name, policy->cpu);
1074 		} else {
1075 			if (!def_gov)
1076 				return -ENODATA;
1077 			gov = def_gov;
1078 		}
1079 		new_policy.governor = gov;
1080 	} else {
1081 		/* Use the default policy if there is no last_policy. */
1082 		if (policy->last_policy) {
1083 			new_policy.policy = policy->last_policy;
1084 		} else {
1085 			if (!def_gov)
1086 				return -ENODATA;
1087 			cpufreq_parse_policy(def_gov->name, &new_policy);
1088 		}
1089 	}
1090 
1091 	return cpufreq_set_policy(policy, &new_policy);
1092 }
1093 
1094 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1095 {
1096 	int ret = 0;
1097 
1098 	/* Has this CPU been taken care of already? */
1099 	if (cpumask_test_cpu(cpu, policy->cpus))
1100 		return 0;
1101 
1102 	down_write(&policy->rwsem);
1103 	if (has_target())
1104 		cpufreq_stop_governor(policy);
1105 
1106 	cpumask_set_cpu(cpu, policy->cpus);
1107 
1108 	if (has_target()) {
1109 		ret = cpufreq_start_governor(policy);
1110 		if (ret)
1111 			pr_err("%s: Failed to start governor\n", __func__);
1112 	}
1113 	up_write(&policy->rwsem);
1114 	return ret;
1115 }
1116 
1117 static void handle_update(struct work_struct *work)
1118 {
1119 	struct cpufreq_policy *policy =
1120 		container_of(work, struct cpufreq_policy, update);
1121 	unsigned int cpu = policy->cpu;
1122 	pr_debug("handle_update for cpu %u called\n", cpu);
1123 	cpufreq_update_policy(cpu);
1124 }
1125 
1126 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1127 {
1128 	struct cpufreq_policy *policy;
1129 	int ret;
1130 
1131 	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1132 	if (!policy)
1133 		return NULL;
1134 
1135 	if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1136 		goto err_free_policy;
1137 
1138 	if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1139 		goto err_free_cpumask;
1140 
1141 	if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1142 		goto err_free_rcpumask;
1143 
1144 	ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1145 				   cpufreq_global_kobject, "policy%u", cpu);
1146 	if (ret) {
1147 		pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1148 		/*
1149 		 * The entire policy object will be freed below, but the extra
1150 		 * memory allocated for the kobject name needs to be freed by
1151 		 * releasing the kobject.
1152 		 */
1153 		kobject_put(&policy->kobj);
1154 		goto err_free_real_cpus;
1155 	}
1156 
1157 	INIT_LIST_HEAD(&policy->policy_list);
1158 	init_rwsem(&policy->rwsem);
1159 	spin_lock_init(&policy->transition_lock);
1160 	init_waitqueue_head(&policy->transition_wait);
1161 	init_completion(&policy->kobj_unregister);
1162 	INIT_WORK(&policy->update, handle_update);
1163 
1164 	policy->cpu = cpu;
1165 	return policy;
1166 
1167 err_free_real_cpus:
1168 	free_cpumask_var(policy->real_cpus);
1169 err_free_rcpumask:
1170 	free_cpumask_var(policy->related_cpus);
1171 err_free_cpumask:
1172 	free_cpumask_var(policy->cpus);
1173 err_free_policy:
1174 	kfree(policy);
1175 
1176 	return NULL;
1177 }
1178 
1179 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1180 {
1181 	struct kobject *kobj;
1182 	struct completion *cmp;
1183 
1184 	down_write(&policy->rwsem);
1185 	cpufreq_stats_free_table(policy);
1186 	kobj = &policy->kobj;
1187 	cmp = &policy->kobj_unregister;
1188 	up_write(&policy->rwsem);
1189 	kobject_put(kobj);
1190 
1191 	/*
1192 	 * We need to make sure that the underlying kobj is
1193 	 * actually not referenced anymore by anybody before we
1194 	 * proceed with unloading.
1195 	 */
1196 	pr_debug("waiting for dropping of refcount\n");
1197 	wait_for_completion(cmp);
1198 	pr_debug("wait complete\n");
1199 }
1200 
1201 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1202 {
1203 	unsigned long flags;
1204 	int cpu;
1205 
1206 	/* Remove policy from list */
1207 	write_lock_irqsave(&cpufreq_driver_lock, flags);
1208 	list_del(&policy->policy_list);
1209 
1210 	for_each_cpu(cpu, policy->related_cpus)
1211 		per_cpu(cpufreq_cpu_data, cpu) = NULL;
1212 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1213 
1214 	cpufreq_policy_put_kobj(policy);
1215 	free_cpumask_var(policy->real_cpus);
1216 	free_cpumask_var(policy->related_cpus);
1217 	free_cpumask_var(policy->cpus);
1218 	kfree(policy);
1219 }
1220 
1221 static int cpufreq_online(unsigned int cpu)
1222 {
1223 	struct cpufreq_policy *policy;
1224 	bool new_policy;
1225 	unsigned long flags;
1226 	unsigned int j;
1227 	int ret;
1228 
1229 	pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1230 
1231 	/* Check if this CPU already has a policy to manage it */
1232 	policy = per_cpu(cpufreq_cpu_data, cpu);
1233 	if (policy) {
1234 		WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1235 		if (!policy_is_inactive(policy))
1236 			return cpufreq_add_policy_cpu(policy, cpu);
1237 
1238 		/* This is the only online CPU for the policy.  Start over. */
1239 		new_policy = false;
1240 		down_write(&policy->rwsem);
1241 		policy->cpu = cpu;
1242 		policy->governor = NULL;
1243 		up_write(&policy->rwsem);
1244 	} else {
1245 		new_policy = true;
1246 		policy = cpufreq_policy_alloc(cpu);
1247 		if (!policy)
1248 			return -ENOMEM;
1249 	}
1250 
1251 	if (!new_policy && cpufreq_driver->online) {
1252 		ret = cpufreq_driver->online(policy);
1253 		if (ret) {
1254 			pr_debug("%s: %d: initialization failed\n", __func__,
1255 				 __LINE__);
1256 			goto out_exit_policy;
1257 		}
1258 
1259 		/* Recover policy->cpus using related_cpus */
1260 		cpumask_copy(policy->cpus, policy->related_cpus);
1261 	} else {
1262 		cpumask_copy(policy->cpus, cpumask_of(cpu));
1263 
1264 		/*
1265 		 * Call driver. From then on the cpufreq must be able
1266 		 * to accept all calls to ->verify and ->setpolicy for this CPU.
1267 		 */
1268 		ret = cpufreq_driver->init(policy);
1269 		if (ret) {
1270 			pr_debug("%s: %d: initialization failed\n", __func__,
1271 				 __LINE__);
1272 			goto out_free_policy;
1273 		}
1274 
1275 		ret = cpufreq_table_validate_and_sort(policy);
1276 		if (ret)
1277 			goto out_exit_policy;
1278 
1279 		/* related_cpus should at least include policy->cpus. */
1280 		cpumask_copy(policy->related_cpus, policy->cpus);
1281 	}
1282 
1283 	down_write(&policy->rwsem);
1284 	/*
1285 	 * affected cpus must always be the one, which are online. We aren't
1286 	 * managing offline cpus here.
1287 	 */
1288 	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1289 
1290 	if (new_policy) {
1291 		policy->user_policy.min = policy->min;
1292 		policy->user_policy.max = policy->max;
1293 
1294 		for_each_cpu(j, policy->related_cpus) {
1295 			per_cpu(cpufreq_cpu_data, j) = policy;
1296 			add_cpu_dev_symlink(policy, j);
1297 		}
1298 	} else {
1299 		policy->min = policy->user_policy.min;
1300 		policy->max = policy->user_policy.max;
1301 	}
1302 
1303 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1304 		policy->cur = cpufreq_driver->get(policy->cpu);
1305 		if (!policy->cur) {
1306 			pr_err("%s: ->get() failed\n", __func__);
1307 			goto out_destroy_policy;
1308 		}
1309 	}
1310 
1311 	/*
1312 	 * Sometimes boot loaders set CPU frequency to a value outside of
1313 	 * frequency table present with cpufreq core. In such cases CPU might be
1314 	 * unstable if it has to run on that frequency for long duration of time
1315 	 * and so its better to set it to a frequency which is specified in
1316 	 * freq-table. This also makes cpufreq stats inconsistent as
1317 	 * cpufreq-stats would fail to register because current frequency of CPU
1318 	 * isn't found in freq-table.
1319 	 *
1320 	 * Because we don't want this change to effect boot process badly, we go
1321 	 * for the next freq which is >= policy->cur ('cur' must be set by now,
1322 	 * otherwise we will end up setting freq to lowest of the table as 'cur'
1323 	 * is initialized to zero).
1324 	 *
1325 	 * We are passing target-freq as "policy->cur - 1" otherwise
1326 	 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1327 	 * equal to target-freq.
1328 	 */
1329 	if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1330 	    && has_target()) {
1331 		/* Are we running at unknown frequency ? */
1332 		ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1333 		if (ret == -EINVAL) {
1334 			/* Warn user and fix it */
1335 			pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1336 				__func__, policy->cpu, policy->cur);
1337 			ret = __cpufreq_driver_target(policy, policy->cur - 1,
1338 				CPUFREQ_RELATION_L);
1339 
1340 			/*
1341 			 * Reaching here after boot in a few seconds may not
1342 			 * mean that system will remain stable at "unknown"
1343 			 * frequency for longer duration. Hence, a BUG_ON().
1344 			 */
1345 			BUG_ON(ret);
1346 			pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1347 				__func__, policy->cpu, policy->cur);
1348 		}
1349 	}
1350 
1351 	if (new_policy) {
1352 		ret = cpufreq_add_dev_interface(policy);
1353 		if (ret)
1354 			goto out_destroy_policy;
1355 
1356 		cpufreq_stats_create_table(policy);
1357 
1358 		write_lock_irqsave(&cpufreq_driver_lock, flags);
1359 		list_add(&policy->policy_list, &cpufreq_policy_list);
1360 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1361 	}
1362 
1363 	ret = cpufreq_init_policy(policy);
1364 	if (ret) {
1365 		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1366 		       __func__, cpu, ret);
1367 		goto out_destroy_policy;
1368 	}
1369 
1370 	up_write(&policy->rwsem);
1371 
1372 	kobject_uevent(&policy->kobj, KOBJ_ADD);
1373 
1374 	/* Callback for handling stuff after policy is ready */
1375 	if (cpufreq_driver->ready)
1376 		cpufreq_driver->ready(policy);
1377 
1378 	if (IS_ENABLED(CONFIG_CPU_THERMAL) &&
1379 	    cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV)
1380 		policy->cdev = of_cpufreq_cooling_register(policy);
1381 
1382 	pr_debug("initialization complete\n");
1383 
1384 	return 0;
1385 
1386 out_destroy_policy:
1387 	for_each_cpu(j, policy->real_cpus)
1388 		remove_cpu_dev_symlink(policy, get_cpu_device(j));
1389 
1390 	up_write(&policy->rwsem);
1391 
1392 out_exit_policy:
1393 	if (cpufreq_driver->exit)
1394 		cpufreq_driver->exit(policy);
1395 
1396 out_free_policy:
1397 	cpufreq_policy_free(policy);
1398 	return ret;
1399 }
1400 
1401 /**
1402  * cpufreq_add_dev - the cpufreq interface for a CPU device.
1403  * @dev: CPU device.
1404  * @sif: Subsystem interface structure pointer (not used)
1405  */
1406 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1407 {
1408 	struct cpufreq_policy *policy;
1409 	unsigned cpu = dev->id;
1410 	int ret;
1411 
1412 	dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1413 
1414 	if (cpu_online(cpu)) {
1415 		ret = cpufreq_online(cpu);
1416 		if (ret)
1417 			return ret;
1418 	}
1419 
1420 	/* Create sysfs link on CPU registration */
1421 	policy = per_cpu(cpufreq_cpu_data, cpu);
1422 	if (policy)
1423 		add_cpu_dev_symlink(policy, cpu);
1424 
1425 	return 0;
1426 }
1427 
1428 static int cpufreq_offline(unsigned int cpu)
1429 {
1430 	struct cpufreq_policy *policy;
1431 	int ret;
1432 
1433 	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1434 
1435 	policy = cpufreq_cpu_get_raw(cpu);
1436 	if (!policy) {
1437 		pr_debug("%s: No cpu_data found\n", __func__);
1438 		return 0;
1439 	}
1440 
1441 	down_write(&policy->rwsem);
1442 	if (has_target())
1443 		cpufreq_stop_governor(policy);
1444 
1445 	cpumask_clear_cpu(cpu, policy->cpus);
1446 
1447 	if (policy_is_inactive(policy)) {
1448 		if (has_target())
1449 			strncpy(policy->last_governor, policy->governor->name,
1450 				CPUFREQ_NAME_LEN);
1451 		else
1452 			policy->last_policy = policy->policy;
1453 	} else if (cpu == policy->cpu) {
1454 		/* Nominate new CPU */
1455 		policy->cpu = cpumask_any(policy->cpus);
1456 	}
1457 
1458 	/* Start governor again for active policy */
1459 	if (!policy_is_inactive(policy)) {
1460 		if (has_target()) {
1461 			ret = cpufreq_start_governor(policy);
1462 			if (ret)
1463 				pr_err("%s: Failed to start governor\n", __func__);
1464 		}
1465 
1466 		goto unlock;
1467 	}
1468 
1469 	if (IS_ENABLED(CONFIG_CPU_THERMAL) &&
1470 	    cpufreq_driver->flags & CPUFREQ_IS_COOLING_DEV) {
1471 		cpufreq_cooling_unregister(policy->cdev);
1472 		policy->cdev = NULL;
1473 	}
1474 
1475 	if (cpufreq_driver->stop_cpu)
1476 		cpufreq_driver->stop_cpu(policy);
1477 
1478 	if (has_target())
1479 		cpufreq_exit_governor(policy);
1480 
1481 	/*
1482 	 * Perform the ->offline() during light-weight tear-down, as
1483 	 * that allows fast recovery when the CPU comes back.
1484 	 */
1485 	if (cpufreq_driver->offline) {
1486 		cpufreq_driver->offline(policy);
1487 	} else if (cpufreq_driver->exit) {
1488 		cpufreq_driver->exit(policy);
1489 		policy->freq_table = NULL;
1490 	}
1491 
1492 unlock:
1493 	up_write(&policy->rwsem);
1494 	return 0;
1495 }
1496 
1497 /**
1498  * cpufreq_remove_dev - remove a CPU device
1499  *
1500  * Removes the cpufreq interface for a CPU device.
1501  */
1502 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1503 {
1504 	unsigned int cpu = dev->id;
1505 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1506 
1507 	if (!policy)
1508 		return;
1509 
1510 	if (cpu_online(cpu))
1511 		cpufreq_offline(cpu);
1512 
1513 	cpumask_clear_cpu(cpu, policy->real_cpus);
1514 	remove_cpu_dev_symlink(policy, dev);
1515 
1516 	if (cpumask_empty(policy->real_cpus)) {
1517 		/* We did light-weight exit earlier, do full tear down now */
1518 		if (cpufreq_driver->offline)
1519 			cpufreq_driver->exit(policy);
1520 
1521 		cpufreq_policy_free(policy);
1522 	}
1523 }
1524 
1525 /**
1526  *	cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1527  *	in deep trouble.
1528  *	@policy: policy managing CPUs
1529  *	@new_freq: CPU frequency the CPU actually runs at
1530  *
1531  *	We adjust to current frequency first, and need to clean up later.
1532  *	So either call to cpufreq_update_policy() or schedule handle_update()).
1533  */
1534 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1535 				unsigned int new_freq)
1536 {
1537 	struct cpufreq_freqs freqs;
1538 
1539 	pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1540 		 policy->cur, new_freq);
1541 
1542 	freqs.old = policy->cur;
1543 	freqs.new = new_freq;
1544 
1545 	cpufreq_freq_transition_begin(policy, &freqs);
1546 	cpufreq_freq_transition_end(policy, &freqs, 0);
1547 }
1548 
1549 /**
1550  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1551  * @cpu: CPU number
1552  *
1553  * This is the last known freq, without actually getting it from the driver.
1554  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1555  */
1556 unsigned int cpufreq_quick_get(unsigned int cpu)
1557 {
1558 	struct cpufreq_policy *policy;
1559 	unsigned int ret_freq = 0;
1560 	unsigned long flags;
1561 
1562 	read_lock_irqsave(&cpufreq_driver_lock, flags);
1563 
1564 	if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1565 		ret_freq = cpufreq_driver->get(cpu);
1566 		read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1567 		return ret_freq;
1568 	}
1569 
1570 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1571 
1572 	policy = cpufreq_cpu_get(cpu);
1573 	if (policy) {
1574 		ret_freq = policy->cur;
1575 		cpufreq_cpu_put(policy);
1576 	}
1577 
1578 	return ret_freq;
1579 }
1580 EXPORT_SYMBOL(cpufreq_quick_get);
1581 
1582 /**
1583  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1584  * @cpu: CPU number
1585  *
1586  * Just return the max possible frequency for a given CPU.
1587  */
1588 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1589 {
1590 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1591 	unsigned int ret_freq = 0;
1592 
1593 	if (policy) {
1594 		ret_freq = policy->max;
1595 		cpufreq_cpu_put(policy);
1596 	}
1597 
1598 	return ret_freq;
1599 }
1600 EXPORT_SYMBOL(cpufreq_quick_get_max);
1601 
1602 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1603 {
1604 	unsigned int ret_freq = 0;
1605 
1606 	if (unlikely(policy_is_inactive(policy)))
1607 		return ret_freq;
1608 
1609 	ret_freq = cpufreq_driver->get(policy->cpu);
1610 
1611 	/*
1612 	 * If fast frequency switching is used with the given policy, the check
1613 	 * against policy->cur is pointless, so skip it in that case too.
1614 	 */
1615 	if (policy->fast_switch_enabled)
1616 		return ret_freq;
1617 
1618 	if (ret_freq && policy->cur &&
1619 		!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1620 		/* verify no discrepancy between actual and
1621 					saved value exists */
1622 		if (unlikely(ret_freq != policy->cur)) {
1623 			cpufreq_out_of_sync(policy, ret_freq);
1624 			schedule_work(&policy->update);
1625 		}
1626 	}
1627 
1628 	return ret_freq;
1629 }
1630 
1631 /**
1632  * cpufreq_get - get the current CPU frequency (in kHz)
1633  * @cpu: CPU number
1634  *
1635  * Get the CPU current (static) CPU frequency
1636  */
1637 unsigned int cpufreq_get(unsigned int cpu)
1638 {
1639 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1640 	unsigned int ret_freq = 0;
1641 
1642 	if (policy) {
1643 		down_read(&policy->rwsem);
1644 		if (cpufreq_driver->get)
1645 			ret_freq = __cpufreq_get(policy);
1646 		up_read(&policy->rwsem);
1647 
1648 		cpufreq_cpu_put(policy);
1649 	}
1650 
1651 	return ret_freq;
1652 }
1653 EXPORT_SYMBOL(cpufreq_get);
1654 
1655 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1656 {
1657 	unsigned int new_freq;
1658 
1659 	new_freq = cpufreq_driver->get(policy->cpu);
1660 	if (!new_freq)
1661 		return 0;
1662 
1663 	if (!policy->cur) {
1664 		pr_debug("cpufreq: Driver did not initialize current freq\n");
1665 		policy->cur = new_freq;
1666 	} else if (policy->cur != new_freq && has_target()) {
1667 		cpufreq_out_of_sync(policy, new_freq);
1668 	}
1669 
1670 	return new_freq;
1671 }
1672 
1673 static struct subsys_interface cpufreq_interface = {
1674 	.name		= "cpufreq",
1675 	.subsys		= &cpu_subsys,
1676 	.add_dev	= cpufreq_add_dev,
1677 	.remove_dev	= cpufreq_remove_dev,
1678 };
1679 
1680 /*
1681  * In case platform wants some specific frequency to be configured
1682  * during suspend..
1683  */
1684 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1685 {
1686 	int ret;
1687 
1688 	if (!policy->suspend_freq) {
1689 		pr_debug("%s: suspend_freq not defined\n", __func__);
1690 		return 0;
1691 	}
1692 
1693 	pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1694 			policy->suspend_freq);
1695 
1696 	ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1697 			CPUFREQ_RELATION_H);
1698 	if (ret)
1699 		pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1700 				__func__, policy->suspend_freq, ret);
1701 
1702 	return ret;
1703 }
1704 EXPORT_SYMBOL(cpufreq_generic_suspend);
1705 
1706 /**
1707  * cpufreq_suspend() - Suspend CPUFreq governors
1708  *
1709  * Called during system wide Suspend/Hibernate cycles for suspending governors
1710  * as some platforms can't change frequency after this point in suspend cycle.
1711  * Because some of the devices (like: i2c, regulators, etc) they use for
1712  * changing frequency are suspended quickly after this point.
1713  */
1714 void cpufreq_suspend(void)
1715 {
1716 	struct cpufreq_policy *policy;
1717 
1718 	if (!cpufreq_driver)
1719 		return;
1720 
1721 	if (!has_target() && !cpufreq_driver->suspend)
1722 		goto suspend;
1723 
1724 	pr_debug("%s: Suspending Governors\n", __func__);
1725 
1726 	for_each_active_policy(policy) {
1727 		if (has_target()) {
1728 			down_write(&policy->rwsem);
1729 			cpufreq_stop_governor(policy);
1730 			up_write(&policy->rwsem);
1731 		}
1732 
1733 		if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1734 			pr_err("%s: Failed to suspend driver: %p\n", __func__,
1735 				policy);
1736 	}
1737 
1738 suspend:
1739 	cpufreq_suspended = true;
1740 }
1741 
1742 /**
1743  * cpufreq_resume() - Resume CPUFreq governors
1744  *
1745  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1746  * are suspended with cpufreq_suspend().
1747  */
1748 void cpufreq_resume(void)
1749 {
1750 	struct cpufreq_policy *policy;
1751 	int ret;
1752 
1753 	if (!cpufreq_driver)
1754 		return;
1755 
1756 	if (unlikely(!cpufreq_suspended))
1757 		return;
1758 
1759 	cpufreq_suspended = false;
1760 
1761 	if (!has_target() && !cpufreq_driver->resume)
1762 		return;
1763 
1764 	pr_debug("%s: Resuming Governors\n", __func__);
1765 
1766 	for_each_active_policy(policy) {
1767 		if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1768 			pr_err("%s: Failed to resume driver: %p\n", __func__,
1769 				policy);
1770 		} else if (has_target()) {
1771 			down_write(&policy->rwsem);
1772 			ret = cpufreq_start_governor(policy);
1773 			up_write(&policy->rwsem);
1774 
1775 			if (ret)
1776 				pr_err("%s: Failed to start governor for policy: %p\n",
1777 				       __func__, policy);
1778 		}
1779 	}
1780 }
1781 
1782 /**
1783  *	cpufreq_get_current_driver - return current driver's name
1784  *
1785  *	Return the name string of the currently loaded cpufreq driver
1786  *	or NULL, if none.
1787  */
1788 const char *cpufreq_get_current_driver(void)
1789 {
1790 	if (cpufreq_driver)
1791 		return cpufreq_driver->name;
1792 
1793 	return NULL;
1794 }
1795 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1796 
1797 /**
1798  *	cpufreq_get_driver_data - return current driver data
1799  *
1800  *	Return the private data of the currently loaded cpufreq
1801  *	driver, or NULL if no cpufreq driver is loaded.
1802  */
1803 void *cpufreq_get_driver_data(void)
1804 {
1805 	if (cpufreq_driver)
1806 		return cpufreq_driver->driver_data;
1807 
1808 	return NULL;
1809 }
1810 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1811 
1812 /*********************************************************************
1813  *                     NOTIFIER LISTS INTERFACE                      *
1814  *********************************************************************/
1815 
1816 /**
1817  *	cpufreq_register_notifier - register a driver with cpufreq
1818  *	@nb: notifier function to register
1819  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1820  *
1821  *	Add a driver to one of two lists: either a list of drivers that
1822  *      are notified about clock rate changes (once before and once after
1823  *      the transition), or a list of drivers that are notified about
1824  *      changes in cpufreq policy.
1825  *
1826  *	This function may sleep, and has the same return conditions as
1827  *	blocking_notifier_chain_register.
1828  */
1829 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1830 {
1831 	int ret;
1832 
1833 	if (cpufreq_disabled())
1834 		return -EINVAL;
1835 
1836 	switch (list) {
1837 	case CPUFREQ_TRANSITION_NOTIFIER:
1838 		mutex_lock(&cpufreq_fast_switch_lock);
1839 
1840 		if (cpufreq_fast_switch_count > 0) {
1841 			mutex_unlock(&cpufreq_fast_switch_lock);
1842 			return -EBUSY;
1843 		}
1844 		ret = srcu_notifier_chain_register(
1845 				&cpufreq_transition_notifier_list, nb);
1846 		if (!ret)
1847 			cpufreq_fast_switch_count--;
1848 
1849 		mutex_unlock(&cpufreq_fast_switch_lock);
1850 		break;
1851 	case CPUFREQ_POLICY_NOTIFIER:
1852 		ret = blocking_notifier_chain_register(
1853 				&cpufreq_policy_notifier_list, nb);
1854 		break;
1855 	default:
1856 		ret = -EINVAL;
1857 	}
1858 
1859 	return ret;
1860 }
1861 EXPORT_SYMBOL(cpufreq_register_notifier);
1862 
1863 /**
1864  *	cpufreq_unregister_notifier - unregister a driver with cpufreq
1865  *	@nb: notifier block to be unregistered
1866  *	@list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1867  *
1868  *	Remove a driver from the CPU frequency notifier list.
1869  *
1870  *	This function may sleep, and has the same return conditions as
1871  *	blocking_notifier_chain_unregister.
1872  */
1873 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1874 {
1875 	int ret;
1876 
1877 	if (cpufreq_disabled())
1878 		return -EINVAL;
1879 
1880 	switch (list) {
1881 	case CPUFREQ_TRANSITION_NOTIFIER:
1882 		mutex_lock(&cpufreq_fast_switch_lock);
1883 
1884 		ret = srcu_notifier_chain_unregister(
1885 				&cpufreq_transition_notifier_list, nb);
1886 		if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1887 			cpufreq_fast_switch_count++;
1888 
1889 		mutex_unlock(&cpufreq_fast_switch_lock);
1890 		break;
1891 	case CPUFREQ_POLICY_NOTIFIER:
1892 		ret = blocking_notifier_chain_unregister(
1893 				&cpufreq_policy_notifier_list, nb);
1894 		break;
1895 	default:
1896 		ret = -EINVAL;
1897 	}
1898 
1899 	return ret;
1900 }
1901 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1902 
1903 
1904 /*********************************************************************
1905  *                              GOVERNORS                            *
1906  *********************************************************************/
1907 
1908 /**
1909  * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1910  * @policy: cpufreq policy to switch the frequency for.
1911  * @target_freq: New frequency to set (may be approximate).
1912  *
1913  * Carry out a fast frequency switch without sleeping.
1914  *
1915  * The driver's ->fast_switch() callback invoked by this function must be
1916  * suitable for being called from within RCU-sched read-side critical sections
1917  * and it is expected to select the minimum available frequency greater than or
1918  * equal to @target_freq (CPUFREQ_RELATION_L).
1919  *
1920  * This function must not be called if policy->fast_switch_enabled is unset.
1921  *
1922  * Governors calling this function must guarantee that it will never be invoked
1923  * twice in parallel for the same policy and that it will never be called in
1924  * parallel with either ->target() or ->target_index() for the same policy.
1925  *
1926  * Returns the actual frequency set for the CPU.
1927  *
1928  * If 0 is returned by the driver's ->fast_switch() callback to indicate an
1929  * error condition, the hardware configuration must be preserved.
1930  */
1931 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1932 					unsigned int target_freq)
1933 {
1934 	target_freq = clamp_val(target_freq, policy->min, policy->max);
1935 
1936 	return cpufreq_driver->fast_switch(policy, target_freq);
1937 }
1938 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1939 
1940 /* Must set freqs->new to intermediate frequency */
1941 static int __target_intermediate(struct cpufreq_policy *policy,
1942 				 struct cpufreq_freqs *freqs, int index)
1943 {
1944 	int ret;
1945 
1946 	freqs->new = cpufreq_driver->get_intermediate(policy, index);
1947 
1948 	/* We don't need to switch to intermediate freq */
1949 	if (!freqs->new)
1950 		return 0;
1951 
1952 	pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1953 		 __func__, policy->cpu, freqs->old, freqs->new);
1954 
1955 	cpufreq_freq_transition_begin(policy, freqs);
1956 	ret = cpufreq_driver->target_intermediate(policy, index);
1957 	cpufreq_freq_transition_end(policy, freqs, ret);
1958 
1959 	if (ret)
1960 		pr_err("%s: Failed to change to intermediate frequency: %d\n",
1961 		       __func__, ret);
1962 
1963 	return ret;
1964 }
1965 
1966 static int __target_index(struct cpufreq_policy *policy, int index)
1967 {
1968 	struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1969 	unsigned int intermediate_freq = 0;
1970 	unsigned int newfreq = policy->freq_table[index].frequency;
1971 	int retval = -EINVAL;
1972 	bool notify;
1973 
1974 	if (newfreq == policy->cur)
1975 		return 0;
1976 
1977 	notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1978 	if (notify) {
1979 		/* Handle switching to intermediate frequency */
1980 		if (cpufreq_driver->get_intermediate) {
1981 			retval = __target_intermediate(policy, &freqs, index);
1982 			if (retval)
1983 				return retval;
1984 
1985 			intermediate_freq = freqs.new;
1986 			/* Set old freq to intermediate */
1987 			if (intermediate_freq)
1988 				freqs.old = freqs.new;
1989 		}
1990 
1991 		freqs.new = newfreq;
1992 		pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1993 			 __func__, policy->cpu, freqs.old, freqs.new);
1994 
1995 		cpufreq_freq_transition_begin(policy, &freqs);
1996 	}
1997 
1998 	retval = cpufreq_driver->target_index(policy, index);
1999 	if (retval)
2000 		pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2001 		       retval);
2002 
2003 	if (notify) {
2004 		cpufreq_freq_transition_end(policy, &freqs, retval);
2005 
2006 		/*
2007 		 * Failed after setting to intermediate freq? Driver should have
2008 		 * reverted back to initial frequency and so should we. Check
2009 		 * here for intermediate_freq instead of get_intermediate, in
2010 		 * case we haven't switched to intermediate freq at all.
2011 		 */
2012 		if (unlikely(retval && intermediate_freq)) {
2013 			freqs.old = intermediate_freq;
2014 			freqs.new = policy->restore_freq;
2015 			cpufreq_freq_transition_begin(policy, &freqs);
2016 			cpufreq_freq_transition_end(policy, &freqs, 0);
2017 		}
2018 	}
2019 
2020 	return retval;
2021 }
2022 
2023 int __cpufreq_driver_target(struct cpufreq_policy *policy,
2024 			    unsigned int target_freq,
2025 			    unsigned int relation)
2026 {
2027 	unsigned int old_target_freq = target_freq;
2028 	int index;
2029 
2030 	if (cpufreq_disabled())
2031 		return -ENODEV;
2032 
2033 	/* Make sure that target_freq is within supported range */
2034 	target_freq = clamp_val(target_freq, policy->min, policy->max);
2035 
2036 	pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2037 		 policy->cpu, target_freq, relation, old_target_freq);
2038 
2039 	/*
2040 	 * This might look like a redundant call as we are checking it again
2041 	 * after finding index. But it is left intentionally for cases where
2042 	 * exactly same freq is called again and so we can save on few function
2043 	 * calls.
2044 	 */
2045 	if (target_freq == policy->cur)
2046 		return 0;
2047 
2048 	/* Save last value to restore later on errors */
2049 	policy->restore_freq = policy->cur;
2050 
2051 	if (cpufreq_driver->target)
2052 		return cpufreq_driver->target(policy, target_freq, relation);
2053 
2054 	if (!cpufreq_driver->target_index)
2055 		return -EINVAL;
2056 
2057 	index = cpufreq_frequency_table_target(policy, target_freq, relation);
2058 
2059 	return __target_index(policy, index);
2060 }
2061 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2062 
2063 int cpufreq_driver_target(struct cpufreq_policy *policy,
2064 			  unsigned int target_freq,
2065 			  unsigned int relation)
2066 {
2067 	int ret = -EINVAL;
2068 
2069 	down_write(&policy->rwsem);
2070 
2071 	ret = __cpufreq_driver_target(policy, target_freq, relation);
2072 
2073 	up_write(&policy->rwsem);
2074 
2075 	return ret;
2076 }
2077 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2078 
2079 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2080 {
2081 	return NULL;
2082 }
2083 
2084 static int cpufreq_init_governor(struct cpufreq_policy *policy)
2085 {
2086 	int ret;
2087 
2088 	/* Don't start any governor operations if we are entering suspend */
2089 	if (cpufreq_suspended)
2090 		return 0;
2091 	/*
2092 	 * Governor might not be initiated here if ACPI _PPC changed
2093 	 * notification happened, so check it.
2094 	 */
2095 	if (!policy->governor)
2096 		return -EINVAL;
2097 
2098 	/* Platform doesn't want dynamic frequency switching ? */
2099 	if (policy->governor->dynamic_switching &&
2100 	    cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2101 		struct cpufreq_governor *gov = cpufreq_fallback_governor();
2102 
2103 		if (gov) {
2104 			pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2105 				policy->governor->name, gov->name);
2106 			policy->governor = gov;
2107 		} else {
2108 			return -EINVAL;
2109 		}
2110 	}
2111 
2112 	if (!try_module_get(policy->governor->owner))
2113 		return -EINVAL;
2114 
2115 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2116 
2117 	if (policy->governor->init) {
2118 		ret = policy->governor->init(policy);
2119 		if (ret) {
2120 			module_put(policy->governor->owner);
2121 			return ret;
2122 		}
2123 	}
2124 
2125 	return 0;
2126 }
2127 
2128 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2129 {
2130 	if (cpufreq_suspended || !policy->governor)
2131 		return;
2132 
2133 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2134 
2135 	if (policy->governor->exit)
2136 		policy->governor->exit(policy);
2137 
2138 	module_put(policy->governor->owner);
2139 }
2140 
2141 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2142 {
2143 	int ret;
2144 
2145 	if (cpufreq_suspended)
2146 		return 0;
2147 
2148 	if (!policy->governor)
2149 		return -EINVAL;
2150 
2151 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2152 
2153 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2154 		cpufreq_update_current_freq(policy);
2155 
2156 	if (policy->governor->start) {
2157 		ret = policy->governor->start(policy);
2158 		if (ret)
2159 			return ret;
2160 	}
2161 
2162 	if (policy->governor->limits)
2163 		policy->governor->limits(policy);
2164 
2165 	return 0;
2166 }
2167 
2168 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2169 {
2170 	if (cpufreq_suspended || !policy->governor)
2171 		return;
2172 
2173 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2174 
2175 	if (policy->governor->stop)
2176 		policy->governor->stop(policy);
2177 }
2178 
2179 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2180 {
2181 	if (cpufreq_suspended || !policy->governor)
2182 		return;
2183 
2184 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2185 
2186 	if (policy->governor->limits)
2187 		policy->governor->limits(policy);
2188 }
2189 
2190 int cpufreq_register_governor(struct cpufreq_governor *governor)
2191 {
2192 	int err;
2193 
2194 	if (!governor)
2195 		return -EINVAL;
2196 
2197 	if (cpufreq_disabled())
2198 		return -ENODEV;
2199 
2200 	mutex_lock(&cpufreq_governor_mutex);
2201 
2202 	err = -EBUSY;
2203 	if (!find_governor(governor->name)) {
2204 		err = 0;
2205 		list_add(&governor->governor_list, &cpufreq_governor_list);
2206 	}
2207 
2208 	mutex_unlock(&cpufreq_governor_mutex);
2209 	return err;
2210 }
2211 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2212 
2213 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2214 {
2215 	struct cpufreq_policy *policy;
2216 	unsigned long flags;
2217 
2218 	if (!governor)
2219 		return;
2220 
2221 	if (cpufreq_disabled())
2222 		return;
2223 
2224 	/* clear last_governor for all inactive policies */
2225 	read_lock_irqsave(&cpufreq_driver_lock, flags);
2226 	for_each_inactive_policy(policy) {
2227 		if (!strcmp(policy->last_governor, governor->name)) {
2228 			policy->governor = NULL;
2229 			strcpy(policy->last_governor, "\0");
2230 		}
2231 	}
2232 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2233 
2234 	mutex_lock(&cpufreq_governor_mutex);
2235 	list_del(&governor->governor_list);
2236 	mutex_unlock(&cpufreq_governor_mutex);
2237 }
2238 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2239 
2240 
2241 /*********************************************************************
2242  *                          POLICY INTERFACE                         *
2243  *********************************************************************/
2244 
2245 /**
2246  * cpufreq_get_policy - get the current cpufreq_policy
2247  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2248  *	is written
2249  *
2250  * Reads the current cpufreq policy.
2251  */
2252 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2253 {
2254 	struct cpufreq_policy *cpu_policy;
2255 	if (!policy)
2256 		return -EINVAL;
2257 
2258 	cpu_policy = cpufreq_cpu_get(cpu);
2259 	if (!cpu_policy)
2260 		return -EINVAL;
2261 
2262 	memcpy(policy, cpu_policy, sizeof(*policy));
2263 
2264 	cpufreq_cpu_put(cpu_policy);
2265 	return 0;
2266 }
2267 EXPORT_SYMBOL(cpufreq_get_policy);
2268 
2269 /**
2270  * cpufreq_set_policy - Modify cpufreq policy parameters.
2271  * @policy: Policy object to modify.
2272  * @new_policy: New policy data.
2273  *
2274  * Pass @new_policy to the cpufreq driver's ->verify() callback, run the
2275  * installed policy notifiers for it with the CPUFREQ_ADJUST value, pass it to
2276  * the driver's ->verify() callback again and run the notifiers for it again
2277  * with the CPUFREQ_NOTIFY value.  Next, copy the min and max parameters
2278  * of @new_policy to @policy and either invoke the driver's ->setpolicy()
2279  * callback (if present) or carry out a governor update for @policy.  That is,
2280  * run the current governor's ->limits() callback (if the governor field in
2281  * @new_policy points to the same object as the one in @policy) or replace the
2282  * governor for @policy with the new one stored in @new_policy.
2283  *
2284  * The cpuinfo part of @policy is not updated by this function.
2285  */
2286 int cpufreq_set_policy(struct cpufreq_policy *policy,
2287 		       struct cpufreq_policy *new_policy)
2288 {
2289 	struct cpufreq_governor *old_gov;
2290 	int ret;
2291 
2292 	pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2293 		 new_policy->cpu, new_policy->min, new_policy->max);
2294 
2295 	memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2296 
2297 	/*
2298 	* This check works well when we store new min/max freq attributes,
2299 	* because new_policy is a copy of policy with one field updated.
2300 	*/
2301 	if (new_policy->min > new_policy->max)
2302 		return -EINVAL;
2303 
2304 	/* verify the cpu speed can be set within this limit */
2305 	ret = cpufreq_driver->verify(new_policy);
2306 	if (ret)
2307 		return ret;
2308 
2309 	/* adjust if necessary - all reasons */
2310 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2311 			CPUFREQ_ADJUST, new_policy);
2312 
2313 	/*
2314 	 * verify the cpu speed can be set within this limit, which might be
2315 	 * different to the first one
2316 	 */
2317 	ret = cpufreq_driver->verify(new_policy);
2318 	if (ret)
2319 		return ret;
2320 
2321 	/* notification of the new policy */
2322 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2323 			CPUFREQ_NOTIFY, new_policy);
2324 
2325 	policy->min = new_policy->min;
2326 	policy->max = new_policy->max;
2327 	trace_cpu_frequency_limits(policy);
2328 
2329 	policy->cached_target_freq = UINT_MAX;
2330 
2331 	pr_debug("new min and max freqs are %u - %u kHz\n",
2332 		 policy->min, policy->max);
2333 
2334 	if (cpufreq_driver->setpolicy) {
2335 		policy->policy = new_policy->policy;
2336 		pr_debug("setting range\n");
2337 		return cpufreq_driver->setpolicy(policy);
2338 	}
2339 
2340 	if (new_policy->governor == policy->governor) {
2341 		pr_debug("governor limits update\n");
2342 		cpufreq_governor_limits(policy);
2343 		return 0;
2344 	}
2345 
2346 	pr_debug("governor switch\n");
2347 
2348 	/* save old, working values */
2349 	old_gov = policy->governor;
2350 	/* end old governor */
2351 	if (old_gov) {
2352 		cpufreq_stop_governor(policy);
2353 		cpufreq_exit_governor(policy);
2354 	}
2355 
2356 	/* start new governor */
2357 	policy->governor = new_policy->governor;
2358 	ret = cpufreq_init_governor(policy);
2359 	if (!ret) {
2360 		ret = cpufreq_start_governor(policy);
2361 		if (!ret) {
2362 			pr_debug("governor change\n");
2363 			sched_cpufreq_governor_change(policy, old_gov);
2364 			return 0;
2365 		}
2366 		cpufreq_exit_governor(policy);
2367 	}
2368 
2369 	/* new governor failed, so re-start old one */
2370 	pr_debug("starting governor %s failed\n", policy->governor->name);
2371 	if (old_gov) {
2372 		policy->governor = old_gov;
2373 		if (cpufreq_init_governor(policy))
2374 			policy->governor = NULL;
2375 		else
2376 			cpufreq_start_governor(policy);
2377 	}
2378 
2379 	return ret;
2380 }
2381 
2382 /**
2383  * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2384  * @cpu: CPU to re-evaluate the policy for.
2385  *
2386  * Update the current frequency for the cpufreq policy of @cpu and use
2387  * cpufreq_set_policy() to re-apply the min and max limits saved in the
2388  * user_policy sub-structure of that policy, which triggers the evaluation
2389  * of policy notifiers and the cpufreq driver's ->verify() callback for the
2390  * policy in question, among other things.
2391  */
2392 void cpufreq_update_policy(unsigned int cpu)
2393 {
2394 	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2395 	struct cpufreq_policy new_policy;
2396 
2397 	if (!policy)
2398 		return;
2399 
2400 	/*
2401 	 * BIOS might change freq behind our back
2402 	 * -> ask driver for current freq and notify governors about a change
2403 	 */
2404 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy &&
2405 	    (cpufreq_suspended || WARN_ON(!cpufreq_update_current_freq(policy))))
2406 		goto unlock;
2407 
2408 	pr_debug("updating policy for CPU %u\n", cpu);
2409 	memcpy(&new_policy, policy, sizeof(*policy));
2410 	new_policy.min = policy->user_policy.min;
2411 	new_policy.max = policy->user_policy.max;
2412 
2413 	cpufreq_set_policy(policy, &new_policy);
2414 
2415 unlock:
2416 	cpufreq_cpu_release(policy);
2417 }
2418 EXPORT_SYMBOL(cpufreq_update_policy);
2419 
2420 /**
2421  * cpufreq_update_limits - Update policy limits for a given CPU.
2422  * @cpu: CPU to update the policy limits for.
2423  *
2424  * Invoke the driver's ->update_limits callback if present or call
2425  * cpufreq_update_policy() for @cpu.
2426  */
2427 void cpufreq_update_limits(unsigned int cpu)
2428 {
2429 	if (cpufreq_driver->update_limits)
2430 		cpufreq_driver->update_limits(cpu);
2431 	else
2432 		cpufreq_update_policy(cpu);
2433 }
2434 EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2435 
2436 /*********************************************************************
2437  *               BOOST						     *
2438  *********************************************************************/
2439 static int cpufreq_boost_set_sw(int state)
2440 {
2441 	struct cpufreq_policy *policy;
2442 	int ret = -EINVAL;
2443 
2444 	for_each_active_policy(policy) {
2445 		if (!policy->freq_table)
2446 			continue;
2447 
2448 		ret = cpufreq_frequency_table_cpuinfo(policy,
2449 						      policy->freq_table);
2450 		if (ret) {
2451 			pr_err("%s: Policy frequency update failed\n",
2452 			       __func__);
2453 			break;
2454 		}
2455 
2456 		down_write(&policy->rwsem);
2457 		policy->user_policy.max = policy->max;
2458 		cpufreq_governor_limits(policy);
2459 		up_write(&policy->rwsem);
2460 	}
2461 
2462 	return ret;
2463 }
2464 
2465 int cpufreq_boost_trigger_state(int state)
2466 {
2467 	unsigned long flags;
2468 	int ret = 0;
2469 
2470 	if (cpufreq_driver->boost_enabled == state)
2471 		return 0;
2472 
2473 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2474 	cpufreq_driver->boost_enabled = state;
2475 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2476 
2477 	ret = cpufreq_driver->set_boost(state);
2478 	if (ret) {
2479 		write_lock_irqsave(&cpufreq_driver_lock, flags);
2480 		cpufreq_driver->boost_enabled = !state;
2481 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2482 
2483 		pr_err("%s: Cannot %s BOOST\n",
2484 		       __func__, state ? "enable" : "disable");
2485 	}
2486 
2487 	return ret;
2488 }
2489 
2490 static bool cpufreq_boost_supported(void)
2491 {
2492 	return cpufreq_driver->set_boost;
2493 }
2494 
2495 static int create_boost_sysfs_file(void)
2496 {
2497 	int ret;
2498 
2499 	ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2500 	if (ret)
2501 		pr_err("%s: cannot register global BOOST sysfs file\n",
2502 		       __func__);
2503 
2504 	return ret;
2505 }
2506 
2507 static void remove_boost_sysfs_file(void)
2508 {
2509 	if (cpufreq_boost_supported())
2510 		sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2511 }
2512 
2513 int cpufreq_enable_boost_support(void)
2514 {
2515 	if (!cpufreq_driver)
2516 		return -EINVAL;
2517 
2518 	if (cpufreq_boost_supported())
2519 		return 0;
2520 
2521 	cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2522 
2523 	/* This will get removed on driver unregister */
2524 	return create_boost_sysfs_file();
2525 }
2526 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2527 
2528 int cpufreq_boost_enabled(void)
2529 {
2530 	return cpufreq_driver->boost_enabled;
2531 }
2532 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2533 
2534 /*********************************************************************
2535  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2536  *********************************************************************/
2537 static enum cpuhp_state hp_online;
2538 
2539 static int cpuhp_cpufreq_online(unsigned int cpu)
2540 {
2541 	cpufreq_online(cpu);
2542 
2543 	return 0;
2544 }
2545 
2546 static int cpuhp_cpufreq_offline(unsigned int cpu)
2547 {
2548 	cpufreq_offline(cpu);
2549 
2550 	return 0;
2551 }
2552 
2553 /**
2554  * cpufreq_register_driver - register a CPU Frequency driver
2555  * @driver_data: A struct cpufreq_driver containing the values#
2556  * submitted by the CPU Frequency driver.
2557  *
2558  * Registers a CPU Frequency driver to this core code. This code
2559  * returns zero on success, -EEXIST when another driver got here first
2560  * (and isn't unregistered in the meantime).
2561  *
2562  */
2563 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2564 {
2565 	unsigned long flags;
2566 	int ret;
2567 
2568 	if (cpufreq_disabled())
2569 		return -ENODEV;
2570 
2571 	if (!driver_data || !driver_data->verify || !driver_data->init ||
2572 	    !(driver_data->setpolicy || driver_data->target_index ||
2573 		    driver_data->target) ||
2574 	     (driver_data->setpolicy && (driver_data->target_index ||
2575 		    driver_data->target)) ||
2576 	     (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2577 	     (!driver_data->online != !driver_data->offline))
2578 		return -EINVAL;
2579 
2580 	pr_debug("trying to register driver %s\n", driver_data->name);
2581 
2582 	/* Protect against concurrent CPU online/offline. */
2583 	cpus_read_lock();
2584 
2585 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2586 	if (cpufreq_driver) {
2587 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2588 		ret = -EEXIST;
2589 		goto out;
2590 	}
2591 	cpufreq_driver = driver_data;
2592 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2593 
2594 	if (driver_data->setpolicy)
2595 		driver_data->flags |= CPUFREQ_CONST_LOOPS;
2596 
2597 	if (cpufreq_boost_supported()) {
2598 		ret = create_boost_sysfs_file();
2599 		if (ret)
2600 			goto err_null_driver;
2601 	}
2602 
2603 	ret = subsys_interface_register(&cpufreq_interface);
2604 	if (ret)
2605 		goto err_boost_unreg;
2606 
2607 	if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2608 	    list_empty(&cpufreq_policy_list)) {
2609 		/* if all ->init() calls failed, unregister */
2610 		ret = -ENODEV;
2611 		pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2612 			 driver_data->name);
2613 		goto err_if_unreg;
2614 	}
2615 
2616 	ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2617 						   "cpufreq:online",
2618 						   cpuhp_cpufreq_online,
2619 						   cpuhp_cpufreq_offline);
2620 	if (ret < 0)
2621 		goto err_if_unreg;
2622 	hp_online = ret;
2623 	ret = 0;
2624 
2625 	pr_debug("driver %s up and running\n", driver_data->name);
2626 	goto out;
2627 
2628 err_if_unreg:
2629 	subsys_interface_unregister(&cpufreq_interface);
2630 err_boost_unreg:
2631 	remove_boost_sysfs_file();
2632 err_null_driver:
2633 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2634 	cpufreq_driver = NULL;
2635 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2636 out:
2637 	cpus_read_unlock();
2638 	return ret;
2639 }
2640 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2641 
2642 /**
2643  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2644  *
2645  * Unregister the current CPUFreq driver. Only call this if you have
2646  * the right to do so, i.e. if you have succeeded in initialising before!
2647  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2648  * currently not initialised.
2649  */
2650 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2651 {
2652 	unsigned long flags;
2653 
2654 	if (!cpufreq_driver || (driver != cpufreq_driver))
2655 		return -EINVAL;
2656 
2657 	pr_debug("unregistering driver %s\n", driver->name);
2658 
2659 	/* Protect against concurrent cpu hotplug */
2660 	cpus_read_lock();
2661 	subsys_interface_unregister(&cpufreq_interface);
2662 	remove_boost_sysfs_file();
2663 	cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2664 
2665 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2666 
2667 	cpufreq_driver = NULL;
2668 
2669 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2670 	cpus_read_unlock();
2671 
2672 	return 0;
2673 }
2674 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2675 
2676 /*
2677  * Stop cpufreq at shutdown to make sure it isn't holding any locks
2678  * or mutexes when secondary CPUs are halted.
2679  */
2680 static struct syscore_ops cpufreq_syscore_ops = {
2681 	.shutdown = cpufreq_suspend,
2682 };
2683 
2684 struct kobject *cpufreq_global_kobject;
2685 EXPORT_SYMBOL(cpufreq_global_kobject);
2686 
2687 static int __init cpufreq_core_init(void)
2688 {
2689 	if (cpufreq_disabled())
2690 		return -ENODEV;
2691 
2692 	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2693 	BUG_ON(!cpufreq_global_kobject);
2694 
2695 	register_syscore_ops(&cpufreq_syscore_ops);
2696 
2697 	return 0;
2698 }
2699 module_param(off, int, 0444);
2700 core_initcall(cpufreq_core_init);
2701