xref: /linux/drivers/cpufreq/cpufreq.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  *  linux/drivers/cpufreq/cpufreq.c
3  *
4  *  Copyright (C) 2001 Russell King
5  *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6  *            (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
7  *
8  *  Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9  *	Added handling for CPU hotplug
10  *  Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11  *	Fix handling for CPU hotplug -- affected CPUs
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License version 2 as
15  * published by the Free Software Foundation.
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
33 
34 static LIST_HEAD(cpufreq_policy_list);
35 
36 static inline bool policy_is_inactive(struct cpufreq_policy *policy)
37 {
38 	return cpumask_empty(policy->cpus);
39 }
40 
41 /* Macros to iterate over CPU policies */
42 #define for_each_suitable_policy(__policy, __active)			 \
43 	list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
44 		if ((__active) == !policy_is_inactive(__policy))
45 
46 #define for_each_active_policy(__policy)		\
47 	for_each_suitable_policy(__policy, true)
48 #define for_each_inactive_policy(__policy)		\
49 	for_each_suitable_policy(__policy, false)
50 
51 #define for_each_policy(__policy)			\
52 	list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
53 
54 /* Iterate over governors */
55 static LIST_HEAD(cpufreq_governor_list);
56 #define for_each_governor(__governor)				\
57 	list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
58 
59 /**
60  * The "cpufreq driver" - the arch- or hardware-dependent low
61  * level driver of CPUFreq support, and its spinlock. This lock
62  * also protects the cpufreq_cpu_data array.
63  */
64 static struct cpufreq_driver *cpufreq_driver;
65 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
66 static DEFINE_RWLOCK(cpufreq_driver_lock);
67 
68 /* Flag to suspend/resume CPUFreq governors */
69 static bool cpufreq_suspended;
70 
71 static inline bool has_target(void)
72 {
73 	return cpufreq_driver->target_index || cpufreq_driver->target;
74 }
75 
76 /* internal prototypes */
77 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
78 static int cpufreq_init_governor(struct cpufreq_policy *policy);
79 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
80 static int cpufreq_start_governor(struct cpufreq_policy *policy);
81 static void cpufreq_stop_governor(struct cpufreq_policy *policy);
82 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
83 
84 /**
85  * Two notifier lists: the "policy" list is involved in the
86  * validation process for a new CPU frequency policy; the
87  * "transition" list for kernel code that needs to handle
88  * changes to devices when the CPU clock speed changes.
89  * The mutex locks both lists.
90  */
91 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
92 static struct srcu_notifier_head cpufreq_transition_notifier_list;
93 
94 static bool init_cpufreq_transition_notifier_list_called;
95 static int __init init_cpufreq_transition_notifier_list(void)
96 {
97 	srcu_init_notifier_head(&cpufreq_transition_notifier_list);
98 	init_cpufreq_transition_notifier_list_called = true;
99 	return 0;
100 }
101 pure_initcall(init_cpufreq_transition_notifier_list);
102 
103 static int off __read_mostly;
104 static int cpufreq_disabled(void)
105 {
106 	return off;
107 }
108 void disable_cpufreq(void)
109 {
110 	off = 1;
111 }
112 static DEFINE_MUTEX(cpufreq_governor_mutex);
113 
114 bool have_governor_per_policy(void)
115 {
116 	return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
117 }
118 EXPORT_SYMBOL_GPL(have_governor_per_policy);
119 
120 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
121 {
122 	if (have_governor_per_policy())
123 		return &policy->kobj;
124 	else
125 		return cpufreq_global_kobject;
126 }
127 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
128 
129 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
130 {
131 	u64 idle_time;
132 	u64 cur_wall_time;
133 	u64 busy_time;
134 
135 	cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
136 
137 	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
138 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
139 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
140 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
141 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
142 	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
143 
144 	idle_time = cur_wall_time - busy_time;
145 	if (wall)
146 		*wall = div_u64(cur_wall_time, NSEC_PER_USEC);
147 
148 	return div_u64(idle_time, NSEC_PER_USEC);
149 }
150 
151 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
152 {
153 	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
154 
155 	if (idle_time == -1ULL)
156 		return get_cpu_idle_time_jiffy(cpu, wall);
157 	else if (!io_busy)
158 		idle_time += get_cpu_iowait_time_us(cpu, wall);
159 
160 	return idle_time;
161 }
162 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
163 
164 /*
165  * This is a generic cpufreq init() routine which can be used by cpufreq
166  * drivers of SMP systems. It will do following:
167  * - validate & show freq table passed
168  * - set policies transition latency
169  * - policy->cpus with all possible CPUs
170  */
171 int cpufreq_generic_init(struct cpufreq_policy *policy,
172 		struct cpufreq_frequency_table *table,
173 		unsigned int transition_latency)
174 {
175 	int ret;
176 
177 	ret = cpufreq_table_validate_and_show(policy, table);
178 	if (ret) {
179 		pr_err("%s: invalid frequency table: %d\n", __func__, ret);
180 		return ret;
181 	}
182 
183 	policy->cpuinfo.transition_latency = transition_latency;
184 
185 	/*
186 	 * The driver only supports the SMP configuration where all processors
187 	 * share the clock and voltage and clock.
188 	 */
189 	cpumask_setall(policy->cpus);
190 
191 	return 0;
192 }
193 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
194 
195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
196 {
197 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
198 
199 	return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
200 }
201 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
202 
203 unsigned int cpufreq_generic_get(unsigned int cpu)
204 {
205 	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
206 
207 	if (!policy || IS_ERR(policy->clk)) {
208 		pr_err("%s: No %s associated to cpu: %d\n",
209 		       __func__, policy ? "clk" : "policy", cpu);
210 		return 0;
211 	}
212 
213 	return clk_get_rate(policy->clk) / 1000;
214 }
215 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
216 
217 /**
218  * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
219  *
220  * @cpu: cpu to find policy for.
221  *
222  * This returns policy for 'cpu', returns NULL if it doesn't exist.
223  * It also increments the kobject reference count to mark it busy and so would
224  * require a corresponding call to cpufreq_cpu_put() to decrement it back.
225  * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
226  * freed as that depends on the kobj count.
227  *
228  * Return: A valid policy on success, otherwise NULL on failure.
229  */
230 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
231 {
232 	struct cpufreq_policy *policy = NULL;
233 	unsigned long flags;
234 
235 	if (WARN_ON(cpu >= nr_cpu_ids))
236 		return NULL;
237 
238 	/* get the cpufreq driver */
239 	read_lock_irqsave(&cpufreq_driver_lock, flags);
240 
241 	if (cpufreq_driver) {
242 		/* get the CPU */
243 		policy = cpufreq_cpu_get_raw(cpu);
244 		if (policy)
245 			kobject_get(&policy->kobj);
246 	}
247 
248 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
249 
250 	return policy;
251 }
252 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
253 
254 /**
255  * cpufreq_cpu_put: Decrements the usage count of a policy
256  *
257  * @policy: policy earlier returned by cpufreq_cpu_get().
258  *
259  * This decrements the kobject reference count incremented earlier by calling
260  * cpufreq_cpu_get().
261  */
262 void cpufreq_cpu_put(struct cpufreq_policy *policy)
263 {
264 	kobject_put(&policy->kobj);
265 }
266 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
267 
268 /*********************************************************************
269  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
270  *********************************************************************/
271 
272 /**
273  * adjust_jiffies - adjust the system "loops_per_jiffy"
274  *
275  * This function alters the system "loops_per_jiffy" for the clock
276  * speed change. Note that loops_per_jiffy cannot be updated on SMP
277  * systems as each CPU might be scaled differently. So, use the arch
278  * per-CPU loops_per_jiffy value wherever possible.
279  */
280 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
281 {
282 #ifndef CONFIG_SMP
283 	static unsigned long l_p_j_ref;
284 	static unsigned int l_p_j_ref_freq;
285 
286 	if (ci->flags & CPUFREQ_CONST_LOOPS)
287 		return;
288 
289 	if (!l_p_j_ref_freq) {
290 		l_p_j_ref = loops_per_jiffy;
291 		l_p_j_ref_freq = ci->old;
292 		pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
293 			 l_p_j_ref, l_p_j_ref_freq);
294 	}
295 	if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
296 		loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
297 								ci->new);
298 		pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
299 			 loops_per_jiffy, ci->new);
300 	}
301 #endif
302 }
303 
304 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
305 		struct cpufreq_freqs *freqs, unsigned int state)
306 {
307 	BUG_ON(irqs_disabled());
308 
309 	if (cpufreq_disabled())
310 		return;
311 
312 	freqs->flags = cpufreq_driver->flags;
313 	pr_debug("notification %u of frequency transition to %u kHz\n",
314 		 state, freqs->new);
315 
316 	switch (state) {
317 
318 	case CPUFREQ_PRECHANGE:
319 		/* detect if the driver reported a value as "old frequency"
320 		 * which is not equal to what the cpufreq core thinks is
321 		 * "old frequency".
322 		 */
323 		if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
324 			if ((policy) && (policy->cpu == freqs->cpu) &&
325 			    (policy->cur) && (policy->cur != freqs->old)) {
326 				pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
327 					 freqs->old, policy->cur);
328 				freqs->old = policy->cur;
329 			}
330 		}
331 		srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
332 				CPUFREQ_PRECHANGE, freqs);
333 		adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
334 		break;
335 
336 	case CPUFREQ_POSTCHANGE:
337 		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
338 		pr_debug("FREQ: %lu - CPU: %lu\n",
339 			 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
340 		trace_cpu_frequency(freqs->new, freqs->cpu);
341 		cpufreq_stats_record_transition(policy, freqs->new);
342 		srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
343 				CPUFREQ_POSTCHANGE, freqs);
344 		if (likely(policy) && likely(policy->cpu == freqs->cpu))
345 			policy->cur = freqs->new;
346 		break;
347 	}
348 }
349 
350 /**
351  * cpufreq_notify_transition - call notifier chain and adjust_jiffies
352  * on frequency transition.
353  *
354  * This function calls the transition notifiers and the "adjust_jiffies"
355  * function. It is called twice on all CPU frequency changes that have
356  * external effects.
357  */
358 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
359 		struct cpufreq_freqs *freqs, unsigned int state)
360 {
361 	for_each_cpu(freqs->cpu, policy->cpus)
362 		__cpufreq_notify_transition(policy, freqs, state);
363 }
364 
365 /* Do post notifications when there are chances that transition has failed */
366 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
367 		struct cpufreq_freqs *freqs, int transition_failed)
368 {
369 	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
370 	if (!transition_failed)
371 		return;
372 
373 	swap(freqs->old, freqs->new);
374 	cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
375 	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
376 }
377 
378 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
379 		struct cpufreq_freqs *freqs)
380 {
381 
382 	/*
383 	 * Catch double invocations of _begin() which lead to self-deadlock.
384 	 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
385 	 * doesn't invoke _begin() on their behalf, and hence the chances of
386 	 * double invocations are very low. Moreover, there are scenarios
387 	 * where these checks can emit false-positive warnings in these
388 	 * drivers; so we avoid that by skipping them altogether.
389 	 */
390 	WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
391 				&& current == policy->transition_task);
392 
393 wait:
394 	wait_event(policy->transition_wait, !policy->transition_ongoing);
395 
396 	spin_lock(&policy->transition_lock);
397 
398 	if (unlikely(policy->transition_ongoing)) {
399 		spin_unlock(&policy->transition_lock);
400 		goto wait;
401 	}
402 
403 	policy->transition_ongoing = true;
404 	policy->transition_task = current;
405 
406 	spin_unlock(&policy->transition_lock);
407 
408 	cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
409 }
410 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
411 
412 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
413 		struct cpufreq_freqs *freqs, int transition_failed)
414 {
415 	if (unlikely(WARN_ON(!policy->transition_ongoing)))
416 		return;
417 
418 	cpufreq_notify_post_transition(policy, freqs, transition_failed);
419 
420 	policy->transition_ongoing = false;
421 	policy->transition_task = NULL;
422 
423 	wake_up(&policy->transition_wait);
424 }
425 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
426 
427 /*
428  * Fast frequency switching status count.  Positive means "enabled", negative
429  * means "disabled" and 0 means "not decided yet".
430  */
431 static int cpufreq_fast_switch_count;
432 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
433 
434 static void cpufreq_list_transition_notifiers(void)
435 {
436 	struct notifier_block *nb;
437 
438 	pr_info("Registered transition notifiers:\n");
439 
440 	mutex_lock(&cpufreq_transition_notifier_list.mutex);
441 
442 	for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
443 		pr_info("%pF\n", nb->notifier_call);
444 
445 	mutex_unlock(&cpufreq_transition_notifier_list.mutex);
446 }
447 
448 /**
449  * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
450  * @policy: cpufreq policy to enable fast frequency switching for.
451  *
452  * Try to enable fast frequency switching for @policy.
453  *
454  * The attempt will fail if there is at least one transition notifier registered
455  * at this point, as fast frequency switching is quite fundamentally at odds
456  * with transition notifiers.  Thus if successful, it will make registration of
457  * transition notifiers fail going forward.
458  */
459 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
460 {
461 	lockdep_assert_held(&policy->rwsem);
462 
463 	if (!policy->fast_switch_possible)
464 		return;
465 
466 	mutex_lock(&cpufreq_fast_switch_lock);
467 	if (cpufreq_fast_switch_count >= 0) {
468 		cpufreq_fast_switch_count++;
469 		policy->fast_switch_enabled = true;
470 	} else {
471 		pr_warn("CPU%u: Fast frequency switching not enabled\n",
472 			policy->cpu);
473 		cpufreq_list_transition_notifiers();
474 	}
475 	mutex_unlock(&cpufreq_fast_switch_lock);
476 }
477 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
478 
479 /**
480  * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
481  * @policy: cpufreq policy to disable fast frequency switching for.
482  */
483 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
484 {
485 	mutex_lock(&cpufreq_fast_switch_lock);
486 	if (policy->fast_switch_enabled) {
487 		policy->fast_switch_enabled = false;
488 		if (!WARN_ON(cpufreq_fast_switch_count <= 0))
489 			cpufreq_fast_switch_count--;
490 	}
491 	mutex_unlock(&cpufreq_fast_switch_lock);
492 }
493 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
494 
495 /**
496  * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
497  * one.
498  * @target_freq: target frequency to resolve.
499  *
500  * The target to driver frequency mapping is cached in the policy.
501  *
502  * Return: Lowest driver-supported frequency greater than or equal to the
503  * given target_freq, subject to policy (min/max) and driver limitations.
504  */
505 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
506 					 unsigned int target_freq)
507 {
508 	target_freq = clamp_val(target_freq, policy->min, policy->max);
509 	policy->cached_target_freq = target_freq;
510 
511 	if (cpufreq_driver->target_index) {
512 		int idx;
513 
514 		idx = cpufreq_frequency_table_target(policy, target_freq,
515 						     CPUFREQ_RELATION_L);
516 		policy->cached_resolved_idx = idx;
517 		return policy->freq_table[idx].frequency;
518 	}
519 
520 	if (cpufreq_driver->resolve_freq)
521 		return cpufreq_driver->resolve_freq(policy, target_freq);
522 
523 	return target_freq;
524 }
525 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
526 
527 /*********************************************************************
528  *                          SYSFS INTERFACE                          *
529  *********************************************************************/
530 static ssize_t show_boost(struct kobject *kobj,
531 				 struct attribute *attr, char *buf)
532 {
533 	return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
534 }
535 
536 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
537 				  const char *buf, size_t count)
538 {
539 	int ret, enable;
540 
541 	ret = sscanf(buf, "%d", &enable);
542 	if (ret != 1 || enable < 0 || enable > 1)
543 		return -EINVAL;
544 
545 	if (cpufreq_boost_trigger_state(enable)) {
546 		pr_err("%s: Cannot %s BOOST!\n",
547 		       __func__, enable ? "enable" : "disable");
548 		return -EINVAL;
549 	}
550 
551 	pr_debug("%s: cpufreq BOOST %s\n",
552 		 __func__, enable ? "enabled" : "disabled");
553 
554 	return count;
555 }
556 define_one_global_rw(boost);
557 
558 static struct cpufreq_governor *find_governor(const char *str_governor)
559 {
560 	struct cpufreq_governor *t;
561 
562 	for_each_governor(t)
563 		if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
564 			return t;
565 
566 	return NULL;
567 }
568 
569 /**
570  * cpufreq_parse_governor - parse a governor string
571  */
572 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
573 				struct cpufreq_governor **governor)
574 {
575 	int err = -EINVAL;
576 
577 	if (cpufreq_driver->setpolicy) {
578 		if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
579 			*policy = CPUFREQ_POLICY_PERFORMANCE;
580 			err = 0;
581 		} else if (!strncasecmp(str_governor, "powersave",
582 						CPUFREQ_NAME_LEN)) {
583 			*policy = CPUFREQ_POLICY_POWERSAVE;
584 			err = 0;
585 		}
586 	} else {
587 		struct cpufreq_governor *t;
588 
589 		mutex_lock(&cpufreq_governor_mutex);
590 
591 		t = find_governor(str_governor);
592 
593 		if (t == NULL) {
594 			int ret;
595 
596 			mutex_unlock(&cpufreq_governor_mutex);
597 			ret = request_module("cpufreq_%s", str_governor);
598 			mutex_lock(&cpufreq_governor_mutex);
599 
600 			if (ret == 0)
601 				t = find_governor(str_governor);
602 		}
603 
604 		if (t != NULL) {
605 			*governor = t;
606 			err = 0;
607 		}
608 
609 		mutex_unlock(&cpufreq_governor_mutex);
610 	}
611 	return err;
612 }
613 
614 /**
615  * cpufreq_per_cpu_attr_read() / show_##file_name() -
616  * print out cpufreq information
617  *
618  * Write out information from cpufreq_driver->policy[cpu]; object must be
619  * "unsigned int".
620  */
621 
622 #define show_one(file_name, object)			\
623 static ssize_t show_##file_name				\
624 (struct cpufreq_policy *policy, char *buf)		\
625 {							\
626 	return sprintf(buf, "%u\n", policy->object);	\
627 }
628 
629 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
630 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
631 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
632 show_one(scaling_min_freq, min);
633 show_one(scaling_max_freq, max);
634 
635 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
636 {
637 	ssize_t ret;
638 
639 	if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
640 		ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
641 	else
642 		ret = sprintf(buf, "%u\n", policy->cur);
643 	return ret;
644 }
645 
646 static int cpufreq_set_policy(struct cpufreq_policy *policy,
647 				struct cpufreq_policy *new_policy);
648 
649 /**
650  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
651  */
652 #define store_one(file_name, object)			\
653 static ssize_t store_##file_name					\
654 (struct cpufreq_policy *policy, const char *buf, size_t count)		\
655 {									\
656 	int ret, temp;							\
657 	struct cpufreq_policy new_policy;				\
658 									\
659 	memcpy(&new_policy, policy, sizeof(*policy));			\
660 									\
661 	ret = sscanf(buf, "%u", &new_policy.object);			\
662 	if (ret != 1)							\
663 		return -EINVAL;						\
664 									\
665 	temp = new_policy.object;					\
666 	ret = cpufreq_set_policy(policy, &new_policy);		\
667 	if (!ret)							\
668 		policy->user_policy.object = temp;			\
669 									\
670 	return ret ? ret : count;					\
671 }
672 
673 store_one(scaling_min_freq, min);
674 store_one(scaling_max_freq, max);
675 
676 /**
677  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
678  */
679 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
680 					char *buf)
681 {
682 	unsigned int cur_freq = __cpufreq_get(policy);
683 
684 	if (cur_freq)
685 		return sprintf(buf, "%u\n", cur_freq);
686 
687 	return sprintf(buf, "<unknown>\n");
688 }
689 
690 /**
691  * show_scaling_governor - show the current policy for the specified CPU
692  */
693 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
694 {
695 	if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
696 		return sprintf(buf, "powersave\n");
697 	else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
698 		return sprintf(buf, "performance\n");
699 	else if (policy->governor)
700 		return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
701 				policy->governor->name);
702 	return -EINVAL;
703 }
704 
705 /**
706  * store_scaling_governor - store policy for the specified CPU
707  */
708 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
709 					const char *buf, size_t count)
710 {
711 	int ret;
712 	char	str_governor[16];
713 	struct cpufreq_policy new_policy;
714 
715 	memcpy(&new_policy, policy, sizeof(*policy));
716 
717 	ret = sscanf(buf, "%15s", str_governor);
718 	if (ret != 1)
719 		return -EINVAL;
720 
721 	if (cpufreq_parse_governor(str_governor, &new_policy.policy,
722 						&new_policy.governor))
723 		return -EINVAL;
724 
725 	ret = cpufreq_set_policy(policy, &new_policy);
726 	return ret ? ret : count;
727 }
728 
729 /**
730  * show_scaling_driver - show the cpufreq driver currently loaded
731  */
732 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
733 {
734 	return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
735 }
736 
737 /**
738  * show_scaling_available_governors - show the available CPUfreq governors
739  */
740 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
741 						char *buf)
742 {
743 	ssize_t i = 0;
744 	struct cpufreq_governor *t;
745 
746 	if (!has_target()) {
747 		i += sprintf(buf, "performance powersave");
748 		goto out;
749 	}
750 
751 	for_each_governor(t) {
752 		if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
753 		    - (CPUFREQ_NAME_LEN + 2)))
754 			goto out;
755 		i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
756 	}
757 out:
758 	i += sprintf(&buf[i], "\n");
759 	return i;
760 }
761 
762 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
763 {
764 	ssize_t i = 0;
765 	unsigned int cpu;
766 
767 	for_each_cpu(cpu, mask) {
768 		if (i)
769 			i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
770 		i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
771 		if (i >= (PAGE_SIZE - 5))
772 			break;
773 	}
774 	i += sprintf(&buf[i], "\n");
775 	return i;
776 }
777 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
778 
779 /**
780  * show_related_cpus - show the CPUs affected by each transition even if
781  * hw coordination is in use
782  */
783 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
784 {
785 	return cpufreq_show_cpus(policy->related_cpus, buf);
786 }
787 
788 /**
789  * show_affected_cpus - show the CPUs affected by each transition
790  */
791 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
792 {
793 	return cpufreq_show_cpus(policy->cpus, buf);
794 }
795 
796 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
797 					const char *buf, size_t count)
798 {
799 	unsigned int freq = 0;
800 	unsigned int ret;
801 
802 	if (!policy->governor || !policy->governor->store_setspeed)
803 		return -EINVAL;
804 
805 	ret = sscanf(buf, "%u", &freq);
806 	if (ret != 1)
807 		return -EINVAL;
808 
809 	policy->governor->store_setspeed(policy, freq);
810 
811 	return count;
812 }
813 
814 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
815 {
816 	if (!policy->governor || !policy->governor->show_setspeed)
817 		return sprintf(buf, "<unsupported>\n");
818 
819 	return policy->governor->show_setspeed(policy, buf);
820 }
821 
822 /**
823  * show_bios_limit - show the current cpufreq HW/BIOS limitation
824  */
825 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
826 {
827 	unsigned int limit;
828 	int ret;
829 	if (cpufreq_driver->bios_limit) {
830 		ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
831 		if (!ret)
832 			return sprintf(buf, "%u\n", limit);
833 	}
834 	return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
835 }
836 
837 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
838 cpufreq_freq_attr_ro(cpuinfo_min_freq);
839 cpufreq_freq_attr_ro(cpuinfo_max_freq);
840 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
841 cpufreq_freq_attr_ro(scaling_available_governors);
842 cpufreq_freq_attr_ro(scaling_driver);
843 cpufreq_freq_attr_ro(scaling_cur_freq);
844 cpufreq_freq_attr_ro(bios_limit);
845 cpufreq_freq_attr_ro(related_cpus);
846 cpufreq_freq_attr_ro(affected_cpus);
847 cpufreq_freq_attr_rw(scaling_min_freq);
848 cpufreq_freq_attr_rw(scaling_max_freq);
849 cpufreq_freq_attr_rw(scaling_governor);
850 cpufreq_freq_attr_rw(scaling_setspeed);
851 
852 static struct attribute *default_attrs[] = {
853 	&cpuinfo_min_freq.attr,
854 	&cpuinfo_max_freq.attr,
855 	&cpuinfo_transition_latency.attr,
856 	&scaling_min_freq.attr,
857 	&scaling_max_freq.attr,
858 	&affected_cpus.attr,
859 	&related_cpus.attr,
860 	&scaling_governor.attr,
861 	&scaling_driver.attr,
862 	&scaling_available_governors.attr,
863 	&scaling_setspeed.attr,
864 	NULL
865 };
866 
867 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
868 #define to_attr(a) container_of(a, struct freq_attr, attr)
869 
870 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
871 {
872 	struct cpufreq_policy *policy = to_policy(kobj);
873 	struct freq_attr *fattr = to_attr(attr);
874 	ssize_t ret;
875 
876 	down_read(&policy->rwsem);
877 	ret = fattr->show(policy, buf);
878 	up_read(&policy->rwsem);
879 
880 	return ret;
881 }
882 
883 static ssize_t store(struct kobject *kobj, struct attribute *attr,
884 		     const char *buf, size_t count)
885 {
886 	struct cpufreq_policy *policy = to_policy(kobj);
887 	struct freq_attr *fattr = to_attr(attr);
888 	ssize_t ret = -EINVAL;
889 
890 	get_online_cpus();
891 
892 	if (cpu_online(policy->cpu)) {
893 		down_write(&policy->rwsem);
894 		ret = fattr->store(policy, buf, count);
895 		up_write(&policy->rwsem);
896 	}
897 
898 	put_online_cpus();
899 
900 	return ret;
901 }
902 
903 static void cpufreq_sysfs_release(struct kobject *kobj)
904 {
905 	struct cpufreq_policy *policy = to_policy(kobj);
906 	pr_debug("last reference is dropped\n");
907 	complete(&policy->kobj_unregister);
908 }
909 
910 static const struct sysfs_ops sysfs_ops = {
911 	.show	= show,
912 	.store	= store,
913 };
914 
915 static struct kobj_type ktype_cpufreq = {
916 	.sysfs_ops	= &sysfs_ops,
917 	.default_attrs	= default_attrs,
918 	.release	= cpufreq_sysfs_release,
919 };
920 
921 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
922 {
923 	struct device *dev = get_cpu_device(cpu);
924 
925 	if (!dev)
926 		return;
927 
928 	if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
929 		return;
930 
931 	dev_dbg(dev, "%s: Adding symlink\n", __func__);
932 	if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
933 		dev_err(dev, "cpufreq symlink creation failed\n");
934 }
935 
936 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
937 				   struct device *dev)
938 {
939 	dev_dbg(dev, "%s: Removing symlink\n", __func__);
940 	sysfs_remove_link(&dev->kobj, "cpufreq");
941 }
942 
943 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
944 {
945 	struct freq_attr **drv_attr;
946 	int ret = 0;
947 
948 	/* set up files for this cpu device */
949 	drv_attr = cpufreq_driver->attr;
950 	while (drv_attr && *drv_attr) {
951 		ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
952 		if (ret)
953 			return ret;
954 		drv_attr++;
955 	}
956 	if (cpufreq_driver->get) {
957 		ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
958 		if (ret)
959 			return ret;
960 	}
961 
962 	ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
963 	if (ret)
964 		return ret;
965 
966 	if (cpufreq_driver->bios_limit) {
967 		ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
968 		if (ret)
969 			return ret;
970 	}
971 
972 	return 0;
973 }
974 
975 __weak struct cpufreq_governor *cpufreq_default_governor(void)
976 {
977 	return NULL;
978 }
979 
980 static int cpufreq_init_policy(struct cpufreq_policy *policy)
981 {
982 	struct cpufreq_governor *gov = NULL;
983 	struct cpufreq_policy new_policy;
984 
985 	memcpy(&new_policy, policy, sizeof(*policy));
986 
987 	/* Update governor of new_policy to the governor used before hotplug */
988 	gov = find_governor(policy->last_governor);
989 	if (gov) {
990 		pr_debug("Restoring governor %s for cpu %d\n",
991 				policy->governor->name, policy->cpu);
992 	} else {
993 		gov = cpufreq_default_governor();
994 		if (!gov)
995 			return -ENODATA;
996 	}
997 
998 	new_policy.governor = gov;
999 
1000 	/* Use the default policy if there is no last_policy. */
1001 	if (cpufreq_driver->setpolicy) {
1002 		if (policy->last_policy)
1003 			new_policy.policy = policy->last_policy;
1004 		else
1005 			cpufreq_parse_governor(gov->name, &new_policy.policy,
1006 					       NULL);
1007 	}
1008 	/* set default policy */
1009 	return cpufreq_set_policy(policy, &new_policy);
1010 }
1011 
1012 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1013 {
1014 	int ret = 0;
1015 
1016 	/* Has this CPU been taken care of already? */
1017 	if (cpumask_test_cpu(cpu, policy->cpus))
1018 		return 0;
1019 
1020 	down_write(&policy->rwsem);
1021 	if (has_target())
1022 		cpufreq_stop_governor(policy);
1023 
1024 	cpumask_set_cpu(cpu, policy->cpus);
1025 
1026 	if (has_target()) {
1027 		ret = cpufreq_start_governor(policy);
1028 		if (ret)
1029 			pr_err("%s: Failed to start governor\n", __func__);
1030 	}
1031 	up_write(&policy->rwsem);
1032 	return ret;
1033 }
1034 
1035 static void handle_update(struct work_struct *work)
1036 {
1037 	struct cpufreq_policy *policy =
1038 		container_of(work, struct cpufreq_policy, update);
1039 	unsigned int cpu = policy->cpu;
1040 	pr_debug("handle_update for cpu %u called\n", cpu);
1041 	cpufreq_update_policy(cpu);
1042 }
1043 
1044 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1045 {
1046 	struct cpufreq_policy *policy;
1047 	int ret;
1048 
1049 	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1050 	if (!policy)
1051 		return NULL;
1052 
1053 	if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1054 		goto err_free_policy;
1055 
1056 	if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1057 		goto err_free_cpumask;
1058 
1059 	if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1060 		goto err_free_rcpumask;
1061 
1062 	ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1063 				   cpufreq_global_kobject, "policy%u", cpu);
1064 	if (ret) {
1065 		pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1066 		goto err_free_real_cpus;
1067 	}
1068 
1069 	INIT_LIST_HEAD(&policy->policy_list);
1070 	init_rwsem(&policy->rwsem);
1071 	spin_lock_init(&policy->transition_lock);
1072 	init_waitqueue_head(&policy->transition_wait);
1073 	init_completion(&policy->kobj_unregister);
1074 	INIT_WORK(&policy->update, handle_update);
1075 
1076 	policy->cpu = cpu;
1077 	return policy;
1078 
1079 err_free_real_cpus:
1080 	free_cpumask_var(policy->real_cpus);
1081 err_free_rcpumask:
1082 	free_cpumask_var(policy->related_cpus);
1083 err_free_cpumask:
1084 	free_cpumask_var(policy->cpus);
1085 err_free_policy:
1086 	kfree(policy);
1087 
1088 	return NULL;
1089 }
1090 
1091 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1092 {
1093 	struct kobject *kobj;
1094 	struct completion *cmp;
1095 
1096 	down_write(&policy->rwsem);
1097 	cpufreq_stats_free_table(policy);
1098 	kobj = &policy->kobj;
1099 	cmp = &policy->kobj_unregister;
1100 	up_write(&policy->rwsem);
1101 	kobject_put(kobj);
1102 
1103 	/*
1104 	 * We need to make sure that the underlying kobj is
1105 	 * actually not referenced anymore by anybody before we
1106 	 * proceed with unloading.
1107 	 */
1108 	pr_debug("waiting for dropping of refcount\n");
1109 	wait_for_completion(cmp);
1110 	pr_debug("wait complete\n");
1111 }
1112 
1113 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1114 {
1115 	unsigned long flags;
1116 	int cpu;
1117 
1118 	/* Remove policy from list */
1119 	write_lock_irqsave(&cpufreq_driver_lock, flags);
1120 	list_del(&policy->policy_list);
1121 
1122 	for_each_cpu(cpu, policy->related_cpus)
1123 		per_cpu(cpufreq_cpu_data, cpu) = NULL;
1124 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1125 
1126 	cpufreq_policy_put_kobj(policy);
1127 	free_cpumask_var(policy->real_cpus);
1128 	free_cpumask_var(policy->related_cpus);
1129 	free_cpumask_var(policy->cpus);
1130 	kfree(policy);
1131 }
1132 
1133 static int cpufreq_online(unsigned int cpu)
1134 {
1135 	struct cpufreq_policy *policy;
1136 	bool new_policy;
1137 	unsigned long flags;
1138 	unsigned int j;
1139 	int ret;
1140 
1141 	pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1142 
1143 	/* Check if this CPU already has a policy to manage it */
1144 	policy = per_cpu(cpufreq_cpu_data, cpu);
1145 	if (policy) {
1146 		WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1147 		if (!policy_is_inactive(policy))
1148 			return cpufreq_add_policy_cpu(policy, cpu);
1149 
1150 		/* This is the only online CPU for the policy.  Start over. */
1151 		new_policy = false;
1152 		down_write(&policy->rwsem);
1153 		policy->cpu = cpu;
1154 		policy->governor = NULL;
1155 		up_write(&policy->rwsem);
1156 	} else {
1157 		new_policy = true;
1158 		policy = cpufreq_policy_alloc(cpu);
1159 		if (!policy)
1160 			return -ENOMEM;
1161 	}
1162 
1163 	cpumask_copy(policy->cpus, cpumask_of(cpu));
1164 
1165 	/* call driver. From then on the cpufreq must be able
1166 	 * to accept all calls to ->verify and ->setpolicy for this CPU
1167 	 */
1168 	ret = cpufreq_driver->init(policy);
1169 	if (ret) {
1170 		pr_debug("initialization failed\n");
1171 		goto out_free_policy;
1172 	}
1173 
1174 	down_write(&policy->rwsem);
1175 
1176 	if (new_policy) {
1177 		/* related_cpus should at least include policy->cpus. */
1178 		cpumask_copy(policy->related_cpus, policy->cpus);
1179 	}
1180 
1181 	/*
1182 	 * affected cpus must always be the one, which are online. We aren't
1183 	 * managing offline cpus here.
1184 	 */
1185 	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1186 
1187 	if (new_policy) {
1188 		policy->user_policy.min = policy->min;
1189 		policy->user_policy.max = policy->max;
1190 
1191 		for_each_cpu(j, policy->related_cpus) {
1192 			per_cpu(cpufreq_cpu_data, j) = policy;
1193 			add_cpu_dev_symlink(policy, j);
1194 		}
1195 	} else {
1196 		policy->min = policy->user_policy.min;
1197 		policy->max = policy->user_policy.max;
1198 	}
1199 
1200 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1201 		policy->cur = cpufreq_driver->get(policy->cpu);
1202 		if (!policy->cur) {
1203 			pr_err("%s: ->get() failed\n", __func__);
1204 			goto out_exit_policy;
1205 		}
1206 	}
1207 
1208 	/*
1209 	 * Sometimes boot loaders set CPU frequency to a value outside of
1210 	 * frequency table present with cpufreq core. In such cases CPU might be
1211 	 * unstable if it has to run on that frequency for long duration of time
1212 	 * and so its better to set it to a frequency which is specified in
1213 	 * freq-table. This also makes cpufreq stats inconsistent as
1214 	 * cpufreq-stats would fail to register because current frequency of CPU
1215 	 * isn't found in freq-table.
1216 	 *
1217 	 * Because we don't want this change to effect boot process badly, we go
1218 	 * for the next freq which is >= policy->cur ('cur' must be set by now,
1219 	 * otherwise we will end up setting freq to lowest of the table as 'cur'
1220 	 * is initialized to zero).
1221 	 *
1222 	 * We are passing target-freq as "policy->cur - 1" otherwise
1223 	 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1224 	 * equal to target-freq.
1225 	 */
1226 	if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1227 	    && has_target()) {
1228 		/* Are we running at unknown frequency ? */
1229 		ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1230 		if (ret == -EINVAL) {
1231 			/* Warn user and fix it */
1232 			pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1233 				__func__, policy->cpu, policy->cur);
1234 			ret = __cpufreq_driver_target(policy, policy->cur - 1,
1235 				CPUFREQ_RELATION_L);
1236 
1237 			/*
1238 			 * Reaching here after boot in a few seconds may not
1239 			 * mean that system will remain stable at "unknown"
1240 			 * frequency for longer duration. Hence, a BUG_ON().
1241 			 */
1242 			BUG_ON(ret);
1243 			pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1244 				__func__, policy->cpu, policy->cur);
1245 		}
1246 	}
1247 
1248 	if (new_policy) {
1249 		ret = cpufreq_add_dev_interface(policy);
1250 		if (ret)
1251 			goto out_exit_policy;
1252 
1253 		cpufreq_stats_create_table(policy);
1254 
1255 		write_lock_irqsave(&cpufreq_driver_lock, flags);
1256 		list_add(&policy->policy_list, &cpufreq_policy_list);
1257 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1258 	}
1259 
1260 	ret = cpufreq_init_policy(policy);
1261 	if (ret) {
1262 		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1263 		       __func__, cpu, ret);
1264 		/* cpufreq_policy_free() will notify based on this */
1265 		new_policy = false;
1266 		goto out_exit_policy;
1267 	}
1268 
1269 	up_write(&policy->rwsem);
1270 
1271 	kobject_uevent(&policy->kobj, KOBJ_ADD);
1272 
1273 	/* Callback for handling stuff after policy is ready */
1274 	if (cpufreq_driver->ready)
1275 		cpufreq_driver->ready(policy);
1276 
1277 	pr_debug("initialization complete\n");
1278 
1279 	return 0;
1280 
1281 out_exit_policy:
1282 	up_write(&policy->rwsem);
1283 
1284 	if (cpufreq_driver->exit)
1285 		cpufreq_driver->exit(policy);
1286 
1287 	for_each_cpu(j, policy->real_cpus)
1288 		remove_cpu_dev_symlink(policy, get_cpu_device(j));
1289 
1290 out_free_policy:
1291 	cpufreq_policy_free(policy);
1292 	return ret;
1293 }
1294 
1295 /**
1296  * cpufreq_add_dev - the cpufreq interface for a CPU device.
1297  * @dev: CPU device.
1298  * @sif: Subsystem interface structure pointer (not used)
1299  */
1300 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1301 {
1302 	struct cpufreq_policy *policy;
1303 	unsigned cpu = dev->id;
1304 	int ret;
1305 
1306 	dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1307 
1308 	if (cpu_online(cpu)) {
1309 		ret = cpufreq_online(cpu);
1310 		if (ret)
1311 			return ret;
1312 	}
1313 
1314 	/* Create sysfs link on CPU registration */
1315 	policy = per_cpu(cpufreq_cpu_data, cpu);
1316 	if (policy)
1317 		add_cpu_dev_symlink(policy, cpu);
1318 
1319 	return 0;
1320 }
1321 
1322 static int cpufreq_offline(unsigned int cpu)
1323 {
1324 	struct cpufreq_policy *policy;
1325 	int ret;
1326 
1327 	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1328 
1329 	policy = cpufreq_cpu_get_raw(cpu);
1330 	if (!policy) {
1331 		pr_debug("%s: No cpu_data found\n", __func__);
1332 		return 0;
1333 	}
1334 
1335 	down_write(&policy->rwsem);
1336 	if (has_target())
1337 		cpufreq_stop_governor(policy);
1338 
1339 	cpumask_clear_cpu(cpu, policy->cpus);
1340 
1341 	if (policy_is_inactive(policy)) {
1342 		if (has_target())
1343 			strncpy(policy->last_governor, policy->governor->name,
1344 				CPUFREQ_NAME_LEN);
1345 		else
1346 			policy->last_policy = policy->policy;
1347 	} else if (cpu == policy->cpu) {
1348 		/* Nominate new CPU */
1349 		policy->cpu = cpumask_any(policy->cpus);
1350 	}
1351 
1352 	/* Start governor again for active policy */
1353 	if (!policy_is_inactive(policy)) {
1354 		if (has_target()) {
1355 			ret = cpufreq_start_governor(policy);
1356 			if (ret)
1357 				pr_err("%s: Failed to start governor\n", __func__);
1358 		}
1359 
1360 		goto unlock;
1361 	}
1362 
1363 	if (cpufreq_driver->stop_cpu)
1364 		cpufreq_driver->stop_cpu(policy);
1365 
1366 	if (has_target())
1367 		cpufreq_exit_governor(policy);
1368 
1369 	/*
1370 	 * Perform the ->exit() even during light-weight tear-down,
1371 	 * since this is a core component, and is essential for the
1372 	 * subsequent light-weight ->init() to succeed.
1373 	 */
1374 	if (cpufreq_driver->exit) {
1375 		cpufreq_driver->exit(policy);
1376 		policy->freq_table = NULL;
1377 	}
1378 
1379 unlock:
1380 	up_write(&policy->rwsem);
1381 	return 0;
1382 }
1383 
1384 /**
1385  * cpufreq_remove_dev - remove a CPU device
1386  *
1387  * Removes the cpufreq interface for a CPU device.
1388  */
1389 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1390 {
1391 	unsigned int cpu = dev->id;
1392 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1393 
1394 	if (!policy)
1395 		return;
1396 
1397 	if (cpu_online(cpu))
1398 		cpufreq_offline(cpu);
1399 
1400 	cpumask_clear_cpu(cpu, policy->real_cpus);
1401 	remove_cpu_dev_symlink(policy, dev);
1402 
1403 	if (cpumask_empty(policy->real_cpus))
1404 		cpufreq_policy_free(policy);
1405 }
1406 
1407 /**
1408  *	cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1409  *	in deep trouble.
1410  *	@policy: policy managing CPUs
1411  *	@new_freq: CPU frequency the CPU actually runs at
1412  *
1413  *	We adjust to current frequency first, and need to clean up later.
1414  *	So either call to cpufreq_update_policy() or schedule handle_update()).
1415  */
1416 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1417 				unsigned int new_freq)
1418 {
1419 	struct cpufreq_freqs freqs;
1420 
1421 	pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1422 		 policy->cur, new_freq);
1423 
1424 	freqs.old = policy->cur;
1425 	freqs.new = new_freq;
1426 
1427 	cpufreq_freq_transition_begin(policy, &freqs);
1428 	cpufreq_freq_transition_end(policy, &freqs, 0);
1429 }
1430 
1431 /**
1432  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1433  * @cpu: CPU number
1434  *
1435  * This is the last known freq, without actually getting it from the driver.
1436  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1437  */
1438 unsigned int cpufreq_quick_get(unsigned int cpu)
1439 {
1440 	struct cpufreq_policy *policy;
1441 	unsigned int ret_freq = 0;
1442 	unsigned long flags;
1443 
1444 	read_lock_irqsave(&cpufreq_driver_lock, flags);
1445 
1446 	if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1447 		ret_freq = cpufreq_driver->get(cpu);
1448 		read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1449 		return ret_freq;
1450 	}
1451 
1452 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1453 
1454 	policy = cpufreq_cpu_get(cpu);
1455 	if (policy) {
1456 		ret_freq = policy->cur;
1457 		cpufreq_cpu_put(policy);
1458 	}
1459 
1460 	return ret_freq;
1461 }
1462 EXPORT_SYMBOL(cpufreq_quick_get);
1463 
1464 /**
1465  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1466  * @cpu: CPU number
1467  *
1468  * Just return the max possible frequency for a given CPU.
1469  */
1470 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1471 {
1472 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1473 	unsigned int ret_freq = 0;
1474 
1475 	if (policy) {
1476 		ret_freq = policy->max;
1477 		cpufreq_cpu_put(policy);
1478 	}
1479 
1480 	return ret_freq;
1481 }
1482 EXPORT_SYMBOL(cpufreq_quick_get_max);
1483 
1484 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1485 {
1486 	unsigned int ret_freq = 0;
1487 
1488 	if (!cpufreq_driver->get)
1489 		return ret_freq;
1490 
1491 	ret_freq = cpufreq_driver->get(policy->cpu);
1492 
1493 	/*
1494 	 * Updating inactive policies is invalid, so avoid doing that.  Also
1495 	 * if fast frequency switching is used with the given policy, the check
1496 	 * against policy->cur is pointless, so skip it in that case too.
1497 	 */
1498 	if (unlikely(policy_is_inactive(policy)) || policy->fast_switch_enabled)
1499 		return ret_freq;
1500 
1501 	if (ret_freq && policy->cur &&
1502 		!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1503 		/* verify no discrepancy between actual and
1504 					saved value exists */
1505 		if (unlikely(ret_freq != policy->cur)) {
1506 			cpufreq_out_of_sync(policy, ret_freq);
1507 			schedule_work(&policy->update);
1508 		}
1509 	}
1510 
1511 	return ret_freq;
1512 }
1513 
1514 /**
1515  * cpufreq_get - get the current CPU frequency (in kHz)
1516  * @cpu: CPU number
1517  *
1518  * Get the CPU current (static) CPU frequency
1519  */
1520 unsigned int cpufreq_get(unsigned int cpu)
1521 {
1522 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1523 	unsigned int ret_freq = 0;
1524 
1525 	if (policy) {
1526 		down_read(&policy->rwsem);
1527 
1528 		if (!policy_is_inactive(policy))
1529 			ret_freq = __cpufreq_get(policy);
1530 
1531 		up_read(&policy->rwsem);
1532 
1533 		cpufreq_cpu_put(policy);
1534 	}
1535 
1536 	return ret_freq;
1537 }
1538 EXPORT_SYMBOL(cpufreq_get);
1539 
1540 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1541 {
1542 	unsigned int new_freq;
1543 
1544 	new_freq = cpufreq_driver->get(policy->cpu);
1545 	if (!new_freq)
1546 		return 0;
1547 
1548 	if (!policy->cur) {
1549 		pr_debug("cpufreq: Driver did not initialize current freq\n");
1550 		policy->cur = new_freq;
1551 	} else if (policy->cur != new_freq && has_target()) {
1552 		cpufreq_out_of_sync(policy, new_freq);
1553 	}
1554 
1555 	return new_freq;
1556 }
1557 
1558 static struct subsys_interface cpufreq_interface = {
1559 	.name		= "cpufreq",
1560 	.subsys		= &cpu_subsys,
1561 	.add_dev	= cpufreq_add_dev,
1562 	.remove_dev	= cpufreq_remove_dev,
1563 };
1564 
1565 /*
1566  * In case platform wants some specific frequency to be configured
1567  * during suspend..
1568  */
1569 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1570 {
1571 	int ret;
1572 
1573 	if (!policy->suspend_freq) {
1574 		pr_debug("%s: suspend_freq not defined\n", __func__);
1575 		return 0;
1576 	}
1577 
1578 	pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1579 			policy->suspend_freq);
1580 
1581 	ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1582 			CPUFREQ_RELATION_H);
1583 	if (ret)
1584 		pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1585 				__func__, policy->suspend_freq, ret);
1586 
1587 	return ret;
1588 }
1589 EXPORT_SYMBOL(cpufreq_generic_suspend);
1590 
1591 /**
1592  * cpufreq_suspend() - Suspend CPUFreq governors
1593  *
1594  * Called during system wide Suspend/Hibernate cycles for suspending governors
1595  * as some platforms can't change frequency after this point in suspend cycle.
1596  * Because some of the devices (like: i2c, regulators, etc) they use for
1597  * changing frequency are suspended quickly after this point.
1598  */
1599 void cpufreq_suspend(void)
1600 {
1601 	struct cpufreq_policy *policy;
1602 
1603 	if (!cpufreq_driver)
1604 		return;
1605 
1606 	if (!has_target() && !cpufreq_driver->suspend)
1607 		goto suspend;
1608 
1609 	pr_debug("%s: Suspending Governors\n", __func__);
1610 
1611 	for_each_active_policy(policy) {
1612 		if (has_target()) {
1613 			down_write(&policy->rwsem);
1614 			cpufreq_stop_governor(policy);
1615 			up_write(&policy->rwsem);
1616 		}
1617 
1618 		if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1619 			pr_err("%s: Failed to suspend driver: %p\n", __func__,
1620 				policy);
1621 	}
1622 
1623 suspend:
1624 	cpufreq_suspended = true;
1625 }
1626 
1627 /**
1628  * cpufreq_resume() - Resume CPUFreq governors
1629  *
1630  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1631  * are suspended with cpufreq_suspend().
1632  */
1633 void cpufreq_resume(void)
1634 {
1635 	struct cpufreq_policy *policy;
1636 	int ret;
1637 
1638 	if (!cpufreq_driver)
1639 		return;
1640 
1641 	cpufreq_suspended = false;
1642 
1643 	if (!has_target() && !cpufreq_driver->resume)
1644 		return;
1645 
1646 	pr_debug("%s: Resuming Governors\n", __func__);
1647 
1648 	for_each_active_policy(policy) {
1649 		if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1650 			pr_err("%s: Failed to resume driver: %p\n", __func__,
1651 				policy);
1652 		} else if (has_target()) {
1653 			down_write(&policy->rwsem);
1654 			ret = cpufreq_start_governor(policy);
1655 			up_write(&policy->rwsem);
1656 
1657 			if (ret)
1658 				pr_err("%s: Failed to start governor for policy: %p\n",
1659 				       __func__, policy);
1660 		}
1661 	}
1662 }
1663 
1664 /**
1665  *	cpufreq_get_current_driver - return current driver's name
1666  *
1667  *	Return the name string of the currently loaded cpufreq driver
1668  *	or NULL, if none.
1669  */
1670 const char *cpufreq_get_current_driver(void)
1671 {
1672 	if (cpufreq_driver)
1673 		return cpufreq_driver->name;
1674 
1675 	return NULL;
1676 }
1677 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1678 
1679 /**
1680  *	cpufreq_get_driver_data - return current driver data
1681  *
1682  *	Return the private data of the currently loaded cpufreq
1683  *	driver, or NULL if no cpufreq driver is loaded.
1684  */
1685 void *cpufreq_get_driver_data(void)
1686 {
1687 	if (cpufreq_driver)
1688 		return cpufreq_driver->driver_data;
1689 
1690 	return NULL;
1691 }
1692 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1693 
1694 /*********************************************************************
1695  *                     NOTIFIER LISTS INTERFACE                      *
1696  *********************************************************************/
1697 
1698 /**
1699  *	cpufreq_register_notifier - register a driver with cpufreq
1700  *	@nb: notifier function to register
1701  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1702  *
1703  *	Add a driver to one of two lists: either a list of drivers that
1704  *      are notified about clock rate changes (once before and once after
1705  *      the transition), or a list of drivers that are notified about
1706  *      changes in cpufreq policy.
1707  *
1708  *	This function may sleep, and has the same return conditions as
1709  *	blocking_notifier_chain_register.
1710  */
1711 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1712 {
1713 	int ret;
1714 
1715 	if (cpufreq_disabled())
1716 		return -EINVAL;
1717 
1718 	WARN_ON(!init_cpufreq_transition_notifier_list_called);
1719 
1720 	switch (list) {
1721 	case CPUFREQ_TRANSITION_NOTIFIER:
1722 		mutex_lock(&cpufreq_fast_switch_lock);
1723 
1724 		if (cpufreq_fast_switch_count > 0) {
1725 			mutex_unlock(&cpufreq_fast_switch_lock);
1726 			return -EBUSY;
1727 		}
1728 		ret = srcu_notifier_chain_register(
1729 				&cpufreq_transition_notifier_list, nb);
1730 		if (!ret)
1731 			cpufreq_fast_switch_count--;
1732 
1733 		mutex_unlock(&cpufreq_fast_switch_lock);
1734 		break;
1735 	case CPUFREQ_POLICY_NOTIFIER:
1736 		ret = blocking_notifier_chain_register(
1737 				&cpufreq_policy_notifier_list, nb);
1738 		break;
1739 	default:
1740 		ret = -EINVAL;
1741 	}
1742 
1743 	return ret;
1744 }
1745 EXPORT_SYMBOL(cpufreq_register_notifier);
1746 
1747 /**
1748  *	cpufreq_unregister_notifier - unregister a driver with cpufreq
1749  *	@nb: notifier block to be unregistered
1750  *	@list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1751  *
1752  *	Remove a driver from the CPU frequency notifier list.
1753  *
1754  *	This function may sleep, and has the same return conditions as
1755  *	blocking_notifier_chain_unregister.
1756  */
1757 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1758 {
1759 	int ret;
1760 
1761 	if (cpufreq_disabled())
1762 		return -EINVAL;
1763 
1764 	switch (list) {
1765 	case CPUFREQ_TRANSITION_NOTIFIER:
1766 		mutex_lock(&cpufreq_fast_switch_lock);
1767 
1768 		ret = srcu_notifier_chain_unregister(
1769 				&cpufreq_transition_notifier_list, nb);
1770 		if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1771 			cpufreq_fast_switch_count++;
1772 
1773 		mutex_unlock(&cpufreq_fast_switch_lock);
1774 		break;
1775 	case CPUFREQ_POLICY_NOTIFIER:
1776 		ret = blocking_notifier_chain_unregister(
1777 				&cpufreq_policy_notifier_list, nb);
1778 		break;
1779 	default:
1780 		ret = -EINVAL;
1781 	}
1782 
1783 	return ret;
1784 }
1785 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1786 
1787 
1788 /*********************************************************************
1789  *                              GOVERNORS                            *
1790  *********************************************************************/
1791 
1792 /**
1793  * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1794  * @policy: cpufreq policy to switch the frequency for.
1795  * @target_freq: New frequency to set (may be approximate).
1796  *
1797  * Carry out a fast frequency switch without sleeping.
1798  *
1799  * The driver's ->fast_switch() callback invoked by this function must be
1800  * suitable for being called from within RCU-sched read-side critical sections
1801  * and it is expected to select the minimum available frequency greater than or
1802  * equal to @target_freq (CPUFREQ_RELATION_L).
1803  *
1804  * This function must not be called if policy->fast_switch_enabled is unset.
1805  *
1806  * Governors calling this function must guarantee that it will never be invoked
1807  * twice in parallel for the same policy and that it will never be called in
1808  * parallel with either ->target() or ->target_index() for the same policy.
1809  *
1810  * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()
1811  * callback to indicate an error condition, the hardware configuration must be
1812  * preserved.
1813  */
1814 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1815 					unsigned int target_freq)
1816 {
1817 	target_freq = clamp_val(target_freq, policy->min, policy->max);
1818 
1819 	return cpufreq_driver->fast_switch(policy, target_freq);
1820 }
1821 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1822 
1823 /* Must set freqs->new to intermediate frequency */
1824 static int __target_intermediate(struct cpufreq_policy *policy,
1825 				 struct cpufreq_freqs *freqs, int index)
1826 {
1827 	int ret;
1828 
1829 	freqs->new = cpufreq_driver->get_intermediate(policy, index);
1830 
1831 	/* We don't need to switch to intermediate freq */
1832 	if (!freqs->new)
1833 		return 0;
1834 
1835 	pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1836 		 __func__, policy->cpu, freqs->old, freqs->new);
1837 
1838 	cpufreq_freq_transition_begin(policy, freqs);
1839 	ret = cpufreq_driver->target_intermediate(policy, index);
1840 	cpufreq_freq_transition_end(policy, freqs, ret);
1841 
1842 	if (ret)
1843 		pr_err("%s: Failed to change to intermediate frequency: %d\n",
1844 		       __func__, ret);
1845 
1846 	return ret;
1847 }
1848 
1849 static int __target_index(struct cpufreq_policy *policy, int index)
1850 {
1851 	struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1852 	unsigned int intermediate_freq = 0;
1853 	unsigned int newfreq = policy->freq_table[index].frequency;
1854 	int retval = -EINVAL;
1855 	bool notify;
1856 
1857 	if (newfreq == policy->cur)
1858 		return 0;
1859 
1860 	notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1861 	if (notify) {
1862 		/* Handle switching to intermediate frequency */
1863 		if (cpufreq_driver->get_intermediate) {
1864 			retval = __target_intermediate(policy, &freqs, index);
1865 			if (retval)
1866 				return retval;
1867 
1868 			intermediate_freq = freqs.new;
1869 			/* Set old freq to intermediate */
1870 			if (intermediate_freq)
1871 				freqs.old = freqs.new;
1872 		}
1873 
1874 		freqs.new = newfreq;
1875 		pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1876 			 __func__, policy->cpu, freqs.old, freqs.new);
1877 
1878 		cpufreq_freq_transition_begin(policy, &freqs);
1879 	}
1880 
1881 	retval = cpufreq_driver->target_index(policy, index);
1882 	if (retval)
1883 		pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1884 		       retval);
1885 
1886 	if (notify) {
1887 		cpufreq_freq_transition_end(policy, &freqs, retval);
1888 
1889 		/*
1890 		 * Failed after setting to intermediate freq? Driver should have
1891 		 * reverted back to initial frequency and so should we. Check
1892 		 * here for intermediate_freq instead of get_intermediate, in
1893 		 * case we haven't switched to intermediate freq at all.
1894 		 */
1895 		if (unlikely(retval && intermediate_freq)) {
1896 			freqs.old = intermediate_freq;
1897 			freqs.new = policy->restore_freq;
1898 			cpufreq_freq_transition_begin(policy, &freqs);
1899 			cpufreq_freq_transition_end(policy, &freqs, 0);
1900 		}
1901 	}
1902 
1903 	return retval;
1904 }
1905 
1906 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1907 			    unsigned int target_freq,
1908 			    unsigned int relation)
1909 {
1910 	unsigned int old_target_freq = target_freq;
1911 	int index;
1912 
1913 	if (cpufreq_disabled())
1914 		return -ENODEV;
1915 
1916 	/* Make sure that target_freq is within supported range */
1917 	target_freq = clamp_val(target_freq, policy->min, policy->max);
1918 
1919 	pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1920 		 policy->cpu, target_freq, relation, old_target_freq);
1921 
1922 	/*
1923 	 * This might look like a redundant call as we are checking it again
1924 	 * after finding index. But it is left intentionally for cases where
1925 	 * exactly same freq is called again and so we can save on few function
1926 	 * calls.
1927 	 */
1928 	if (target_freq == policy->cur)
1929 		return 0;
1930 
1931 	/* Save last value to restore later on errors */
1932 	policy->restore_freq = policy->cur;
1933 
1934 	if (cpufreq_driver->target)
1935 		return cpufreq_driver->target(policy, target_freq, relation);
1936 
1937 	if (!cpufreq_driver->target_index)
1938 		return -EINVAL;
1939 
1940 	index = cpufreq_frequency_table_target(policy, target_freq, relation);
1941 
1942 	return __target_index(policy, index);
1943 }
1944 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1945 
1946 int cpufreq_driver_target(struct cpufreq_policy *policy,
1947 			  unsigned int target_freq,
1948 			  unsigned int relation)
1949 {
1950 	int ret = -EINVAL;
1951 
1952 	down_write(&policy->rwsem);
1953 
1954 	ret = __cpufreq_driver_target(policy, target_freq, relation);
1955 
1956 	up_write(&policy->rwsem);
1957 
1958 	return ret;
1959 }
1960 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1961 
1962 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1963 {
1964 	return NULL;
1965 }
1966 
1967 static int cpufreq_init_governor(struct cpufreq_policy *policy)
1968 {
1969 	int ret;
1970 
1971 	/* Don't start any governor operations if we are entering suspend */
1972 	if (cpufreq_suspended)
1973 		return 0;
1974 	/*
1975 	 * Governor might not be initiated here if ACPI _PPC changed
1976 	 * notification happened, so check it.
1977 	 */
1978 	if (!policy->governor)
1979 		return -EINVAL;
1980 
1981 	if (policy->governor->max_transition_latency &&
1982 	    policy->cpuinfo.transition_latency >
1983 	    policy->governor->max_transition_latency) {
1984 		struct cpufreq_governor *gov = cpufreq_fallback_governor();
1985 
1986 		if (gov) {
1987 			pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1988 				policy->governor->name, gov->name);
1989 			policy->governor = gov;
1990 		} else {
1991 			return -EINVAL;
1992 		}
1993 	}
1994 
1995 	if (!try_module_get(policy->governor->owner))
1996 		return -EINVAL;
1997 
1998 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
1999 
2000 	if (policy->governor->init) {
2001 		ret = policy->governor->init(policy);
2002 		if (ret) {
2003 			module_put(policy->governor->owner);
2004 			return ret;
2005 		}
2006 	}
2007 
2008 	return 0;
2009 }
2010 
2011 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2012 {
2013 	if (cpufreq_suspended || !policy->governor)
2014 		return;
2015 
2016 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2017 
2018 	if (policy->governor->exit)
2019 		policy->governor->exit(policy);
2020 
2021 	module_put(policy->governor->owner);
2022 }
2023 
2024 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2025 {
2026 	int ret;
2027 
2028 	if (cpufreq_suspended)
2029 		return 0;
2030 
2031 	if (!policy->governor)
2032 		return -EINVAL;
2033 
2034 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2035 
2036 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2037 		cpufreq_update_current_freq(policy);
2038 
2039 	if (policy->governor->start) {
2040 		ret = policy->governor->start(policy);
2041 		if (ret)
2042 			return ret;
2043 	}
2044 
2045 	if (policy->governor->limits)
2046 		policy->governor->limits(policy);
2047 
2048 	return 0;
2049 }
2050 
2051 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2052 {
2053 	if (cpufreq_suspended || !policy->governor)
2054 		return;
2055 
2056 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2057 
2058 	if (policy->governor->stop)
2059 		policy->governor->stop(policy);
2060 }
2061 
2062 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2063 {
2064 	if (cpufreq_suspended || !policy->governor)
2065 		return;
2066 
2067 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2068 
2069 	if (policy->governor->limits)
2070 		policy->governor->limits(policy);
2071 }
2072 
2073 int cpufreq_register_governor(struct cpufreq_governor *governor)
2074 {
2075 	int err;
2076 
2077 	if (!governor)
2078 		return -EINVAL;
2079 
2080 	if (cpufreq_disabled())
2081 		return -ENODEV;
2082 
2083 	mutex_lock(&cpufreq_governor_mutex);
2084 
2085 	err = -EBUSY;
2086 	if (!find_governor(governor->name)) {
2087 		err = 0;
2088 		list_add(&governor->governor_list, &cpufreq_governor_list);
2089 	}
2090 
2091 	mutex_unlock(&cpufreq_governor_mutex);
2092 	return err;
2093 }
2094 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2095 
2096 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2097 {
2098 	struct cpufreq_policy *policy;
2099 	unsigned long flags;
2100 
2101 	if (!governor)
2102 		return;
2103 
2104 	if (cpufreq_disabled())
2105 		return;
2106 
2107 	/* clear last_governor for all inactive policies */
2108 	read_lock_irqsave(&cpufreq_driver_lock, flags);
2109 	for_each_inactive_policy(policy) {
2110 		if (!strcmp(policy->last_governor, governor->name)) {
2111 			policy->governor = NULL;
2112 			strcpy(policy->last_governor, "\0");
2113 		}
2114 	}
2115 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2116 
2117 	mutex_lock(&cpufreq_governor_mutex);
2118 	list_del(&governor->governor_list);
2119 	mutex_unlock(&cpufreq_governor_mutex);
2120 	return;
2121 }
2122 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2123 
2124 
2125 /*********************************************************************
2126  *                          POLICY INTERFACE                         *
2127  *********************************************************************/
2128 
2129 /**
2130  * cpufreq_get_policy - get the current cpufreq_policy
2131  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2132  *	is written
2133  *
2134  * Reads the current cpufreq policy.
2135  */
2136 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2137 {
2138 	struct cpufreq_policy *cpu_policy;
2139 	if (!policy)
2140 		return -EINVAL;
2141 
2142 	cpu_policy = cpufreq_cpu_get(cpu);
2143 	if (!cpu_policy)
2144 		return -EINVAL;
2145 
2146 	memcpy(policy, cpu_policy, sizeof(*policy));
2147 
2148 	cpufreq_cpu_put(cpu_policy);
2149 	return 0;
2150 }
2151 EXPORT_SYMBOL(cpufreq_get_policy);
2152 
2153 /*
2154  * policy : current policy.
2155  * new_policy: policy to be set.
2156  */
2157 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2158 				struct cpufreq_policy *new_policy)
2159 {
2160 	struct cpufreq_governor *old_gov;
2161 	int ret;
2162 
2163 	pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2164 		 new_policy->cpu, new_policy->min, new_policy->max);
2165 
2166 	memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2167 
2168 	/*
2169 	* This check works well when we store new min/max freq attributes,
2170 	* because new_policy is a copy of policy with one field updated.
2171 	*/
2172 	if (new_policy->min > new_policy->max)
2173 		return -EINVAL;
2174 
2175 	/* verify the cpu speed can be set within this limit */
2176 	ret = cpufreq_driver->verify(new_policy);
2177 	if (ret)
2178 		return ret;
2179 
2180 	/* adjust if necessary - all reasons */
2181 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2182 			CPUFREQ_ADJUST, new_policy);
2183 
2184 	/*
2185 	 * verify the cpu speed can be set within this limit, which might be
2186 	 * different to the first one
2187 	 */
2188 	ret = cpufreq_driver->verify(new_policy);
2189 	if (ret)
2190 		return ret;
2191 
2192 	/* notification of the new policy */
2193 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2194 			CPUFREQ_NOTIFY, new_policy);
2195 
2196 	policy->min = new_policy->min;
2197 	policy->max = new_policy->max;
2198 
2199 	policy->cached_target_freq = UINT_MAX;
2200 
2201 	pr_debug("new min and max freqs are %u - %u kHz\n",
2202 		 policy->min, policy->max);
2203 
2204 	if (cpufreq_driver->setpolicy) {
2205 		policy->policy = new_policy->policy;
2206 		pr_debug("setting range\n");
2207 		return cpufreq_driver->setpolicy(new_policy);
2208 	}
2209 
2210 	if (new_policy->governor == policy->governor) {
2211 		pr_debug("cpufreq: governor limits update\n");
2212 		cpufreq_governor_limits(policy);
2213 		return 0;
2214 	}
2215 
2216 	pr_debug("governor switch\n");
2217 
2218 	/* save old, working values */
2219 	old_gov = policy->governor;
2220 	/* end old governor */
2221 	if (old_gov) {
2222 		cpufreq_stop_governor(policy);
2223 		cpufreq_exit_governor(policy);
2224 	}
2225 
2226 	/* start new governor */
2227 	policy->governor = new_policy->governor;
2228 	ret = cpufreq_init_governor(policy);
2229 	if (!ret) {
2230 		ret = cpufreq_start_governor(policy);
2231 		if (!ret) {
2232 			pr_debug("cpufreq: governor change\n");
2233 			return 0;
2234 		}
2235 		cpufreq_exit_governor(policy);
2236 	}
2237 
2238 	/* new governor failed, so re-start old one */
2239 	pr_debug("starting governor %s failed\n", policy->governor->name);
2240 	if (old_gov) {
2241 		policy->governor = old_gov;
2242 		if (cpufreq_init_governor(policy))
2243 			policy->governor = NULL;
2244 		else
2245 			cpufreq_start_governor(policy);
2246 	}
2247 
2248 	return ret;
2249 }
2250 
2251 /**
2252  *	cpufreq_update_policy - re-evaluate an existing cpufreq policy
2253  *	@cpu: CPU which shall be re-evaluated
2254  *
2255  *	Useful for policy notifiers which have different necessities
2256  *	at different times.
2257  */
2258 void cpufreq_update_policy(unsigned int cpu)
2259 {
2260 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2261 	struct cpufreq_policy new_policy;
2262 
2263 	if (!policy)
2264 		return;
2265 
2266 	down_write(&policy->rwsem);
2267 
2268 	if (policy_is_inactive(policy))
2269 		goto unlock;
2270 
2271 	pr_debug("updating policy for CPU %u\n", cpu);
2272 	memcpy(&new_policy, policy, sizeof(*policy));
2273 	new_policy.min = policy->user_policy.min;
2274 	new_policy.max = policy->user_policy.max;
2275 
2276 	/*
2277 	 * BIOS might change freq behind our back
2278 	 * -> ask driver for current freq and notify governors about a change
2279 	 */
2280 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2281 		if (cpufreq_suspended)
2282 			goto unlock;
2283 
2284 		new_policy.cur = cpufreq_update_current_freq(policy);
2285 		if (WARN_ON(!new_policy.cur))
2286 			goto unlock;
2287 	}
2288 
2289 	cpufreq_set_policy(policy, &new_policy);
2290 
2291 unlock:
2292 	up_write(&policy->rwsem);
2293 
2294 	cpufreq_cpu_put(policy);
2295 }
2296 EXPORT_SYMBOL(cpufreq_update_policy);
2297 
2298 /*********************************************************************
2299  *               BOOST						     *
2300  *********************************************************************/
2301 static int cpufreq_boost_set_sw(int state)
2302 {
2303 	struct cpufreq_policy *policy;
2304 	int ret = -EINVAL;
2305 
2306 	for_each_active_policy(policy) {
2307 		if (!policy->freq_table)
2308 			continue;
2309 
2310 		ret = cpufreq_frequency_table_cpuinfo(policy,
2311 						      policy->freq_table);
2312 		if (ret) {
2313 			pr_err("%s: Policy frequency update failed\n",
2314 			       __func__);
2315 			break;
2316 		}
2317 
2318 		down_write(&policy->rwsem);
2319 		policy->user_policy.max = policy->max;
2320 		cpufreq_governor_limits(policy);
2321 		up_write(&policy->rwsem);
2322 	}
2323 
2324 	return ret;
2325 }
2326 
2327 int cpufreq_boost_trigger_state(int state)
2328 {
2329 	unsigned long flags;
2330 	int ret = 0;
2331 
2332 	if (cpufreq_driver->boost_enabled == state)
2333 		return 0;
2334 
2335 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2336 	cpufreq_driver->boost_enabled = state;
2337 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2338 
2339 	ret = cpufreq_driver->set_boost(state);
2340 	if (ret) {
2341 		write_lock_irqsave(&cpufreq_driver_lock, flags);
2342 		cpufreq_driver->boost_enabled = !state;
2343 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2344 
2345 		pr_err("%s: Cannot %s BOOST\n",
2346 		       __func__, state ? "enable" : "disable");
2347 	}
2348 
2349 	return ret;
2350 }
2351 
2352 static bool cpufreq_boost_supported(void)
2353 {
2354 	return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2355 }
2356 
2357 static int create_boost_sysfs_file(void)
2358 {
2359 	int ret;
2360 
2361 	ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2362 	if (ret)
2363 		pr_err("%s: cannot register global BOOST sysfs file\n",
2364 		       __func__);
2365 
2366 	return ret;
2367 }
2368 
2369 static void remove_boost_sysfs_file(void)
2370 {
2371 	if (cpufreq_boost_supported())
2372 		sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2373 }
2374 
2375 int cpufreq_enable_boost_support(void)
2376 {
2377 	if (!cpufreq_driver)
2378 		return -EINVAL;
2379 
2380 	if (cpufreq_boost_supported())
2381 		return 0;
2382 
2383 	cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2384 
2385 	/* This will get removed on driver unregister */
2386 	return create_boost_sysfs_file();
2387 }
2388 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2389 
2390 int cpufreq_boost_enabled(void)
2391 {
2392 	return cpufreq_driver->boost_enabled;
2393 }
2394 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2395 
2396 /*********************************************************************
2397  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2398  *********************************************************************/
2399 static enum cpuhp_state hp_online;
2400 
2401 static int cpuhp_cpufreq_online(unsigned int cpu)
2402 {
2403 	cpufreq_online(cpu);
2404 
2405 	return 0;
2406 }
2407 
2408 static int cpuhp_cpufreq_offline(unsigned int cpu)
2409 {
2410 	cpufreq_offline(cpu);
2411 
2412 	return 0;
2413 }
2414 
2415 /**
2416  * cpufreq_register_driver - register a CPU Frequency driver
2417  * @driver_data: A struct cpufreq_driver containing the values#
2418  * submitted by the CPU Frequency driver.
2419  *
2420  * Registers a CPU Frequency driver to this core code. This code
2421  * returns zero on success, -EEXIST when another driver got here first
2422  * (and isn't unregistered in the meantime).
2423  *
2424  */
2425 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2426 {
2427 	unsigned long flags;
2428 	int ret;
2429 
2430 	if (cpufreq_disabled())
2431 		return -ENODEV;
2432 
2433 	if (!driver_data || !driver_data->verify || !driver_data->init ||
2434 	    !(driver_data->setpolicy || driver_data->target_index ||
2435 		    driver_data->target) ||
2436 	     (driver_data->setpolicy && (driver_data->target_index ||
2437 		    driver_data->target)) ||
2438 	     (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2439 		return -EINVAL;
2440 
2441 	pr_debug("trying to register driver %s\n", driver_data->name);
2442 
2443 	/* Protect against concurrent CPU online/offline. */
2444 	get_online_cpus();
2445 
2446 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2447 	if (cpufreq_driver) {
2448 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2449 		ret = -EEXIST;
2450 		goto out;
2451 	}
2452 	cpufreq_driver = driver_data;
2453 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2454 
2455 	if (driver_data->setpolicy)
2456 		driver_data->flags |= CPUFREQ_CONST_LOOPS;
2457 
2458 	if (cpufreq_boost_supported()) {
2459 		ret = create_boost_sysfs_file();
2460 		if (ret)
2461 			goto err_null_driver;
2462 	}
2463 
2464 	ret = subsys_interface_register(&cpufreq_interface);
2465 	if (ret)
2466 		goto err_boost_unreg;
2467 
2468 	if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2469 	    list_empty(&cpufreq_policy_list)) {
2470 		/* if all ->init() calls failed, unregister */
2471 		pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2472 			 driver_data->name);
2473 		goto err_if_unreg;
2474 	}
2475 
2476 	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online",
2477 					cpuhp_cpufreq_online,
2478 					cpuhp_cpufreq_offline);
2479 	if (ret < 0)
2480 		goto err_if_unreg;
2481 	hp_online = ret;
2482 	ret = 0;
2483 
2484 	pr_debug("driver %s up and running\n", driver_data->name);
2485 	goto out;
2486 
2487 err_if_unreg:
2488 	subsys_interface_unregister(&cpufreq_interface);
2489 err_boost_unreg:
2490 	remove_boost_sysfs_file();
2491 err_null_driver:
2492 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2493 	cpufreq_driver = NULL;
2494 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2495 out:
2496 	put_online_cpus();
2497 	return ret;
2498 }
2499 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2500 
2501 /**
2502  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2503  *
2504  * Unregister the current CPUFreq driver. Only call this if you have
2505  * the right to do so, i.e. if you have succeeded in initialising before!
2506  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2507  * currently not initialised.
2508  */
2509 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2510 {
2511 	unsigned long flags;
2512 
2513 	if (!cpufreq_driver || (driver != cpufreq_driver))
2514 		return -EINVAL;
2515 
2516 	pr_debug("unregistering driver %s\n", driver->name);
2517 
2518 	/* Protect against concurrent cpu hotplug */
2519 	get_online_cpus();
2520 	subsys_interface_unregister(&cpufreq_interface);
2521 	remove_boost_sysfs_file();
2522 	cpuhp_remove_state_nocalls(hp_online);
2523 
2524 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2525 
2526 	cpufreq_driver = NULL;
2527 
2528 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2529 	put_online_cpus();
2530 
2531 	return 0;
2532 }
2533 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2534 
2535 /*
2536  * Stop cpufreq at shutdown to make sure it isn't holding any locks
2537  * or mutexes when secondary CPUs are halted.
2538  */
2539 static struct syscore_ops cpufreq_syscore_ops = {
2540 	.shutdown = cpufreq_suspend,
2541 };
2542 
2543 struct kobject *cpufreq_global_kobject;
2544 EXPORT_SYMBOL(cpufreq_global_kobject);
2545 
2546 static int __init cpufreq_core_init(void)
2547 {
2548 	if (cpufreq_disabled())
2549 		return -ENODEV;
2550 
2551 	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2552 	BUG_ON(!cpufreq_global_kobject);
2553 
2554 	register_syscore_ops(&cpufreq_syscore_ops);
2555 
2556 	return 0;
2557 }
2558 module_param(off, int, 0444);
2559 core_initcall(cpufreq_core_init);
2560