xref: /linux/drivers/cpufreq/cpufreq.c (revision d060296cc0300ae8ed08004ebd3994bf325fa257)
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 __weak unsigned int arch_freq_get_on_cpu(int cpu)
636 {
637 	return 0;
638 }
639 
640 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
641 {
642 	ssize_t ret;
643 	unsigned int freq;
644 
645 	freq = arch_freq_get_on_cpu(policy->cpu);
646 	if (freq)
647 		ret = sprintf(buf, "%u\n", freq);
648 	else if (cpufreq_driver && cpufreq_driver->setpolicy &&
649 			cpufreq_driver->get)
650 		ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
651 	else
652 		ret = sprintf(buf, "%u\n", policy->cur);
653 	return ret;
654 }
655 
656 static int cpufreq_set_policy(struct cpufreq_policy *policy,
657 				struct cpufreq_policy *new_policy);
658 
659 /**
660  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
661  */
662 #define store_one(file_name, object)			\
663 static ssize_t store_##file_name					\
664 (struct cpufreq_policy *policy, const char *buf, size_t count)		\
665 {									\
666 	int ret, temp;							\
667 	struct cpufreq_policy new_policy;				\
668 									\
669 	memcpy(&new_policy, policy, sizeof(*policy));			\
670 									\
671 	ret = sscanf(buf, "%u", &new_policy.object);			\
672 	if (ret != 1)							\
673 		return -EINVAL;						\
674 									\
675 	temp = new_policy.object;					\
676 	ret = cpufreq_set_policy(policy, &new_policy);		\
677 	if (!ret)							\
678 		policy->user_policy.object = temp;			\
679 									\
680 	return ret ? ret : count;					\
681 }
682 
683 store_one(scaling_min_freq, min);
684 store_one(scaling_max_freq, max);
685 
686 /**
687  * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
688  */
689 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
690 					char *buf)
691 {
692 	unsigned int cur_freq = __cpufreq_get(policy);
693 
694 	if (cur_freq)
695 		return sprintf(buf, "%u\n", cur_freq);
696 
697 	return sprintf(buf, "<unknown>\n");
698 }
699 
700 /**
701  * show_scaling_governor - show the current policy for the specified CPU
702  */
703 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
704 {
705 	if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
706 		return sprintf(buf, "powersave\n");
707 	else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
708 		return sprintf(buf, "performance\n");
709 	else if (policy->governor)
710 		return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
711 				policy->governor->name);
712 	return -EINVAL;
713 }
714 
715 /**
716  * store_scaling_governor - store policy for the specified CPU
717  */
718 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
719 					const char *buf, size_t count)
720 {
721 	int ret;
722 	char	str_governor[16];
723 	struct cpufreq_policy new_policy;
724 
725 	memcpy(&new_policy, policy, sizeof(*policy));
726 
727 	ret = sscanf(buf, "%15s", str_governor);
728 	if (ret != 1)
729 		return -EINVAL;
730 
731 	if (cpufreq_parse_governor(str_governor, &new_policy.policy,
732 						&new_policy.governor))
733 		return -EINVAL;
734 
735 	ret = cpufreq_set_policy(policy, &new_policy);
736 	return ret ? ret : count;
737 }
738 
739 /**
740  * show_scaling_driver - show the cpufreq driver currently loaded
741  */
742 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
743 {
744 	return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
745 }
746 
747 /**
748  * show_scaling_available_governors - show the available CPUfreq governors
749  */
750 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
751 						char *buf)
752 {
753 	ssize_t i = 0;
754 	struct cpufreq_governor *t;
755 
756 	if (!has_target()) {
757 		i += sprintf(buf, "performance powersave");
758 		goto out;
759 	}
760 
761 	for_each_governor(t) {
762 		if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
763 		    - (CPUFREQ_NAME_LEN + 2)))
764 			goto out;
765 		i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
766 	}
767 out:
768 	i += sprintf(&buf[i], "\n");
769 	return i;
770 }
771 
772 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
773 {
774 	ssize_t i = 0;
775 	unsigned int cpu;
776 
777 	for_each_cpu(cpu, mask) {
778 		if (i)
779 			i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
780 		i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
781 		if (i >= (PAGE_SIZE - 5))
782 			break;
783 	}
784 	i += sprintf(&buf[i], "\n");
785 	return i;
786 }
787 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
788 
789 /**
790  * show_related_cpus - show the CPUs affected by each transition even if
791  * hw coordination is in use
792  */
793 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
794 {
795 	return cpufreq_show_cpus(policy->related_cpus, buf);
796 }
797 
798 /**
799  * show_affected_cpus - show the CPUs affected by each transition
800  */
801 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
802 {
803 	return cpufreq_show_cpus(policy->cpus, buf);
804 }
805 
806 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
807 					const char *buf, size_t count)
808 {
809 	unsigned int freq = 0;
810 	unsigned int ret;
811 
812 	if (!policy->governor || !policy->governor->store_setspeed)
813 		return -EINVAL;
814 
815 	ret = sscanf(buf, "%u", &freq);
816 	if (ret != 1)
817 		return -EINVAL;
818 
819 	policy->governor->store_setspeed(policy, freq);
820 
821 	return count;
822 }
823 
824 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
825 {
826 	if (!policy->governor || !policy->governor->show_setspeed)
827 		return sprintf(buf, "<unsupported>\n");
828 
829 	return policy->governor->show_setspeed(policy, buf);
830 }
831 
832 /**
833  * show_bios_limit - show the current cpufreq HW/BIOS limitation
834  */
835 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
836 {
837 	unsigned int limit;
838 	int ret;
839 	if (cpufreq_driver->bios_limit) {
840 		ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
841 		if (!ret)
842 			return sprintf(buf, "%u\n", limit);
843 	}
844 	return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
845 }
846 
847 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
848 cpufreq_freq_attr_ro(cpuinfo_min_freq);
849 cpufreq_freq_attr_ro(cpuinfo_max_freq);
850 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
851 cpufreq_freq_attr_ro(scaling_available_governors);
852 cpufreq_freq_attr_ro(scaling_driver);
853 cpufreq_freq_attr_ro(scaling_cur_freq);
854 cpufreq_freq_attr_ro(bios_limit);
855 cpufreq_freq_attr_ro(related_cpus);
856 cpufreq_freq_attr_ro(affected_cpus);
857 cpufreq_freq_attr_rw(scaling_min_freq);
858 cpufreq_freq_attr_rw(scaling_max_freq);
859 cpufreq_freq_attr_rw(scaling_governor);
860 cpufreq_freq_attr_rw(scaling_setspeed);
861 
862 static struct attribute *default_attrs[] = {
863 	&cpuinfo_min_freq.attr,
864 	&cpuinfo_max_freq.attr,
865 	&cpuinfo_transition_latency.attr,
866 	&scaling_min_freq.attr,
867 	&scaling_max_freq.attr,
868 	&affected_cpus.attr,
869 	&related_cpus.attr,
870 	&scaling_governor.attr,
871 	&scaling_driver.attr,
872 	&scaling_available_governors.attr,
873 	&scaling_setspeed.attr,
874 	NULL
875 };
876 
877 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
878 #define to_attr(a) container_of(a, struct freq_attr, attr)
879 
880 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
881 {
882 	struct cpufreq_policy *policy = to_policy(kobj);
883 	struct freq_attr *fattr = to_attr(attr);
884 	ssize_t ret;
885 
886 	down_read(&policy->rwsem);
887 	ret = fattr->show(policy, buf);
888 	up_read(&policy->rwsem);
889 
890 	return ret;
891 }
892 
893 static ssize_t store(struct kobject *kobj, struct attribute *attr,
894 		     const char *buf, size_t count)
895 {
896 	struct cpufreq_policy *policy = to_policy(kobj);
897 	struct freq_attr *fattr = to_attr(attr);
898 	ssize_t ret = -EINVAL;
899 
900 	cpus_read_lock();
901 
902 	if (cpu_online(policy->cpu)) {
903 		down_write(&policy->rwsem);
904 		ret = fattr->store(policy, buf, count);
905 		up_write(&policy->rwsem);
906 	}
907 
908 	cpus_read_unlock();
909 
910 	return ret;
911 }
912 
913 static void cpufreq_sysfs_release(struct kobject *kobj)
914 {
915 	struct cpufreq_policy *policy = to_policy(kobj);
916 	pr_debug("last reference is dropped\n");
917 	complete(&policy->kobj_unregister);
918 }
919 
920 static const struct sysfs_ops sysfs_ops = {
921 	.show	= show,
922 	.store	= store,
923 };
924 
925 static struct kobj_type ktype_cpufreq = {
926 	.sysfs_ops	= &sysfs_ops,
927 	.default_attrs	= default_attrs,
928 	.release	= cpufreq_sysfs_release,
929 };
930 
931 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
932 {
933 	struct device *dev = get_cpu_device(cpu);
934 
935 	if (!dev)
936 		return;
937 
938 	if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
939 		return;
940 
941 	dev_dbg(dev, "%s: Adding symlink\n", __func__);
942 	if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
943 		dev_err(dev, "cpufreq symlink creation failed\n");
944 }
945 
946 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
947 				   struct device *dev)
948 {
949 	dev_dbg(dev, "%s: Removing symlink\n", __func__);
950 	sysfs_remove_link(&dev->kobj, "cpufreq");
951 }
952 
953 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
954 {
955 	struct freq_attr **drv_attr;
956 	int ret = 0;
957 
958 	/* set up files for this cpu device */
959 	drv_attr = cpufreq_driver->attr;
960 	while (drv_attr && *drv_attr) {
961 		ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
962 		if (ret)
963 			return ret;
964 		drv_attr++;
965 	}
966 	if (cpufreq_driver->get) {
967 		ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
968 		if (ret)
969 			return ret;
970 	}
971 
972 	ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
973 	if (ret)
974 		return ret;
975 
976 	if (cpufreq_driver->bios_limit) {
977 		ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
978 		if (ret)
979 			return ret;
980 	}
981 
982 	return 0;
983 }
984 
985 __weak struct cpufreq_governor *cpufreq_default_governor(void)
986 {
987 	return NULL;
988 }
989 
990 static int cpufreq_init_policy(struct cpufreq_policy *policy)
991 {
992 	struct cpufreq_governor *gov = NULL;
993 	struct cpufreq_policy new_policy;
994 
995 	memcpy(&new_policy, policy, sizeof(*policy));
996 
997 	/* Update governor of new_policy to the governor used before hotplug */
998 	gov = find_governor(policy->last_governor);
999 	if (gov) {
1000 		pr_debug("Restoring governor %s for cpu %d\n",
1001 				policy->governor->name, policy->cpu);
1002 	} else {
1003 		gov = cpufreq_default_governor();
1004 		if (!gov)
1005 			return -ENODATA;
1006 	}
1007 
1008 	new_policy.governor = gov;
1009 
1010 	/* Use the default policy if there is no last_policy. */
1011 	if (cpufreq_driver->setpolicy) {
1012 		if (policy->last_policy)
1013 			new_policy.policy = policy->last_policy;
1014 		else
1015 			cpufreq_parse_governor(gov->name, &new_policy.policy,
1016 					       NULL);
1017 	}
1018 	/* set default policy */
1019 	return cpufreq_set_policy(policy, &new_policy);
1020 }
1021 
1022 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1023 {
1024 	int ret = 0;
1025 
1026 	/* Has this CPU been taken care of already? */
1027 	if (cpumask_test_cpu(cpu, policy->cpus))
1028 		return 0;
1029 
1030 	down_write(&policy->rwsem);
1031 	if (has_target())
1032 		cpufreq_stop_governor(policy);
1033 
1034 	cpumask_set_cpu(cpu, policy->cpus);
1035 
1036 	if (has_target()) {
1037 		ret = cpufreq_start_governor(policy);
1038 		if (ret)
1039 			pr_err("%s: Failed to start governor\n", __func__);
1040 	}
1041 	up_write(&policy->rwsem);
1042 	return ret;
1043 }
1044 
1045 static void handle_update(struct work_struct *work)
1046 {
1047 	struct cpufreq_policy *policy =
1048 		container_of(work, struct cpufreq_policy, update);
1049 	unsigned int cpu = policy->cpu;
1050 	pr_debug("handle_update for cpu %u called\n", cpu);
1051 	cpufreq_update_policy(cpu);
1052 }
1053 
1054 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1055 {
1056 	struct cpufreq_policy *policy;
1057 	int ret;
1058 
1059 	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1060 	if (!policy)
1061 		return NULL;
1062 
1063 	if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1064 		goto err_free_policy;
1065 
1066 	if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1067 		goto err_free_cpumask;
1068 
1069 	if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1070 		goto err_free_rcpumask;
1071 
1072 	ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1073 				   cpufreq_global_kobject, "policy%u", cpu);
1074 	if (ret) {
1075 		pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1076 		goto err_free_real_cpus;
1077 	}
1078 
1079 	INIT_LIST_HEAD(&policy->policy_list);
1080 	init_rwsem(&policy->rwsem);
1081 	spin_lock_init(&policy->transition_lock);
1082 	init_waitqueue_head(&policy->transition_wait);
1083 	init_completion(&policy->kobj_unregister);
1084 	INIT_WORK(&policy->update, handle_update);
1085 
1086 	policy->cpu = cpu;
1087 	return policy;
1088 
1089 err_free_real_cpus:
1090 	free_cpumask_var(policy->real_cpus);
1091 err_free_rcpumask:
1092 	free_cpumask_var(policy->related_cpus);
1093 err_free_cpumask:
1094 	free_cpumask_var(policy->cpus);
1095 err_free_policy:
1096 	kfree(policy);
1097 
1098 	return NULL;
1099 }
1100 
1101 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1102 {
1103 	struct kobject *kobj;
1104 	struct completion *cmp;
1105 
1106 	down_write(&policy->rwsem);
1107 	cpufreq_stats_free_table(policy);
1108 	kobj = &policy->kobj;
1109 	cmp = &policy->kobj_unregister;
1110 	up_write(&policy->rwsem);
1111 	kobject_put(kobj);
1112 
1113 	/*
1114 	 * We need to make sure that the underlying kobj is
1115 	 * actually not referenced anymore by anybody before we
1116 	 * proceed with unloading.
1117 	 */
1118 	pr_debug("waiting for dropping of refcount\n");
1119 	wait_for_completion(cmp);
1120 	pr_debug("wait complete\n");
1121 }
1122 
1123 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1124 {
1125 	unsigned long flags;
1126 	int cpu;
1127 
1128 	/* Remove policy from list */
1129 	write_lock_irqsave(&cpufreq_driver_lock, flags);
1130 	list_del(&policy->policy_list);
1131 
1132 	for_each_cpu(cpu, policy->related_cpus)
1133 		per_cpu(cpufreq_cpu_data, cpu) = NULL;
1134 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1135 
1136 	cpufreq_policy_put_kobj(policy);
1137 	free_cpumask_var(policy->real_cpus);
1138 	free_cpumask_var(policy->related_cpus);
1139 	free_cpumask_var(policy->cpus);
1140 	kfree(policy);
1141 }
1142 
1143 static int cpufreq_online(unsigned int cpu)
1144 {
1145 	struct cpufreq_policy *policy;
1146 	bool new_policy;
1147 	unsigned long flags;
1148 	unsigned int j;
1149 	int ret;
1150 
1151 	pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1152 
1153 	/* Check if this CPU already has a policy to manage it */
1154 	policy = per_cpu(cpufreq_cpu_data, cpu);
1155 	if (policy) {
1156 		WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1157 		if (!policy_is_inactive(policy))
1158 			return cpufreq_add_policy_cpu(policy, cpu);
1159 
1160 		/* This is the only online CPU for the policy.  Start over. */
1161 		new_policy = false;
1162 		down_write(&policy->rwsem);
1163 		policy->cpu = cpu;
1164 		policy->governor = NULL;
1165 		up_write(&policy->rwsem);
1166 	} else {
1167 		new_policy = true;
1168 		policy = cpufreq_policy_alloc(cpu);
1169 		if (!policy)
1170 			return -ENOMEM;
1171 	}
1172 
1173 	cpumask_copy(policy->cpus, cpumask_of(cpu));
1174 
1175 	/* call driver. From then on the cpufreq must be able
1176 	 * to accept all calls to ->verify and ->setpolicy for this CPU
1177 	 */
1178 	ret = cpufreq_driver->init(policy);
1179 	if (ret) {
1180 		pr_debug("initialization failed\n");
1181 		goto out_free_policy;
1182 	}
1183 
1184 	down_write(&policy->rwsem);
1185 
1186 	if (new_policy) {
1187 		/* related_cpus should at least include policy->cpus. */
1188 		cpumask_copy(policy->related_cpus, policy->cpus);
1189 	}
1190 
1191 	/*
1192 	 * affected cpus must always be the one, which are online. We aren't
1193 	 * managing offline cpus here.
1194 	 */
1195 	cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1196 
1197 	if (new_policy) {
1198 		policy->user_policy.min = policy->min;
1199 		policy->user_policy.max = policy->max;
1200 
1201 		for_each_cpu(j, policy->related_cpus) {
1202 			per_cpu(cpufreq_cpu_data, j) = policy;
1203 			add_cpu_dev_symlink(policy, j);
1204 		}
1205 	} else {
1206 		policy->min = policy->user_policy.min;
1207 		policy->max = policy->user_policy.max;
1208 	}
1209 
1210 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1211 		policy->cur = cpufreq_driver->get(policy->cpu);
1212 		if (!policy->cur) {
1213 			pr_err("%s: ->get() failed\n", __func__);
1214 			goto out_exit_policy;
1215 		}
1216 	}
1217 
1218 	/*
1219 	 * Sometimes boot loaders set CPU frequency to a value outside of
1220 	 * frequency table present with cpufreq core. In such cases CPU might be
1221 	 * unstable if it has to run on that frequency for long duration of time
1222 	 * and so its better to set it to a frequency which is specified in
1223 	 * freq-table. This also makes cpufreq stats inconsistent as
1224 	 * cpufreq-stats would fail to register because current frequency of CPU
1225 	 * isn't found in freq-table.
1226 	 *
1227 	 * Because we don't want this change to effect boot process badly, we go
1228 	 * for the next freq which is >= policy->cur ('cur' must be set by now,
1229 	 * otherwise we will end up setting freq to lowest of the table as 'cur'
1230 	 * is initialized to zero).
1231 	 *
1232 	 * We are passing target-freq as "policy->cur - 1" otherwise
1233 	 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1234 	 * equal to target-freq.
1235 	 */
1236 	if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1237 	    && has_target()) {
1238 		/* Are we running at unknown frequency ? */
1239 		ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1240 		if (ret == -EINVAL) {
1241 			/* Warn user and fix it */
1242 			pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1243 				__func__, policy->cpu, policy->cur);
1244 			ret = __cpufreq_driver_target(policy, policy->cur - 1,
1245 				CPUFREQ_RELATION_L);
1246 
1247 			/*
1248 			 * Reaching here after boot in a few seconds may not
1249 			 * mean that system will remain stable at "unknown"
1250 			 * frequency for longer duration. Hence, a BUG_ON().
1251 			 */
1252 			BUG_ON(ret);
1253 			pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1254 				__func__, policy->cpu, policy->cur);
1255 		}
1256 	}
1257 
1258 	if (new_policy) {
1259 		ret = cpufreq_add_dev_interface(policy);
1260 		if (ret)
1261 			goto out_exit_policy;
1262 
1263 		cpufreq_stats_create_table(policy);
1264 
1265 		write_lock_irqsave(&cpufreq_driver_lock, flags);
1266 		list_add(&policy->policy_list, &cpufreq_policy_list);
1267 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1268 	}
1269 
1270 	ret = cpufreq_init_policy(policy);
1271 	if (ret) {
1272 		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1273 		       __func__, cpu, ret);
1274 		/* cpufreq_policy_free() will notify based on this */
1275 		new_policy = false;
1276 		goto out_exit_policy;
1277 	}
1278 
1279 	up_write(&policy->rwsem);
1280 
1281 	kobject_uevent(&policy->kobj, KOBJ_ADD);
1282 
1283 	/* Callback for handling stuff after policy is ready */
1284 	if (cpufreq_driver->ready)
1285 		cpufreq_driver->ready(policy);
1286 
1287 	pr_debug("initialization complete\n");
1288 
1289 	return 0;
1290 
1291 out_exit_policy:
1292 	up_write(&policy->rwsem);
1293 
1294 	if (cpufreq_driver->exit)
1295 		cpufreq_driver->exit(policy);
1296 
1297 	for_each_cpu(j, policy->real_cpus)
1298 		remove_cpu_dev_symlink(policy, get_cpu_device(j));
1299 
1300 out_free_policy:
1301 	cpufreq_policy_free(policy);
1302 	return ret;
1303 }
1304 
1305 /**
1306  * cpufreq_add_dev - the cpufreq interface for a CPU device.
1307  * @dev: CPU device.
1308  * @sif: Subsystem interface structure pointer (not used)
1309  */
1310 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1311 {
1312 	struct cpufreq_policy *policy;
1313 	unsigned cpu = dev->id;
1314 	int ret;
1315 
1316 	dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1317 
1318 	if (cpu_online(cpu)) {
1319 		ret = cpufreq_online(cpu);
1320 		if (ret)
1321 			return ret;
1322 	}
1323 
1324 	/* Create sysfs link on CPU registration */
1325 	policy = per_cpu(cpufreq_cpu_data, cpu);
1326 	if (policy)
1327 		add_cpu_dev_symlink(policy, cpu);
1328 
1329 	return 0;
1330 }
1331 
1332 static int cpufreq_offline(unsigned int cpu)
1333 {
1334 	struct cpufreq_policy *policy;
1335 	int ret;
1336 
1337 	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1338 
1339 	policy = cpufreq_cpu_get_raw(cpu);
1340 	if (!policy) {
1341 		pr_debug("%s: No cpu_data found\n", __func__);
1342 		return 0;
1343 	}
1344 
1345 	down_write(&policy->rwsem);
1346 	if (has_target())
1347 		cpufreq_stop_governor(policy);
1348 
1349 	cpumask_clear_cpu(cpu, policy->cpus);
1350 
1351 	if (policy_is_inactive(policy)) {
1352 		if (has_target())
1353 			strncpy(policy->last_governor, policy->governor->name,
1354 				CPUFREQ_NAME_LEN);
1355 		else
1356 			policy->last_policy = policy->policy;
1357 	} else if (cpu == policy->cpu) {
1358 		/* Nominate new CPU */
1359 		policy->cpu = cpumask_any(policy->cpus);
1360 	}
1361 
1362 	/* Start governor again for active policy */
1363 	if (!policy_is_inactive(policy)) {
1364 		if (has_target()) {
1365 			ret = cpufreq_start_governor(policy);
1366 			if (ret)
1367 				pr_err("%s: Failed to start governor\n", __func__);
1368 		}
1369 
1370 		goto unlock;
1371 	}
1372 
1373 	if (cpufreq_driver->stop_cpu)
1374 		cpufreq_driver->stop_cpu(policy);
1375 
1376 	if (has_target())
1377 		cpufreq_exit_governor(policy);
1378 
1379 	/*
1380 	 * Perform the ->exit() even during light-weight tear-down,
1381 	 * since this is a core component, and is essential for the
1382 	 * subsequent light-weight ->init() to succeed.
1383 	 */
1384 	if (cpufreq_driver->exit) {
1385 		cpufreq_driver->exit(policy);
1386 		policy->freq_table = NULL;
1387 	}
1388 
1389 unlock:
1390 	up_write(&policy->rwsem);
1391 	return 0;
1392 }
1393 
1394 /**
1395  * cpufreq_remove_dev - remove a CPU device
1396  *
1397  * Removes the cpufreq interface for a CPU device.
1398  */
1399 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1400 {
1401 	unsigned int cpu = dev->id;
1402 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1403 
1404 	if (!policy)
1405 		return;
1406 
1407 	if (cpu_online(cpu))
1408 		cpufreq_offline(cpu);
1409 
1410 	cpumask_clear_cpu(cpu, policy->real_cpus);
1411 	remove_cpu_dev_symlink(policy, dev);
1412 
1413 	if (cpumask_empty(policy->real_cpus))
1414 		cpufreq_policy_free(policy);
1415 }
1416 
1417 /**
1418  *	cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1419  *	in deep trouble.
1420  *	@policy: policy managing CPUs
1421  *	@new_freq: CPU frequency the CPU actually runs at
1422  *
1423  *	We adjust to current frequency first, and need to clean up later.
1424  *	So either call to cpufreq_update_policy() or schedule handle_update()).
1425  */
1426 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1427 				unsigned int new_freq)
1428 {
1429 	struct cpufreq_freqs freqs;
1430 
1431 	pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1432 		 policy->cur, new_freq);
1433 
1434 	freqs.old = policy->cur;
1435 	freqs.new = new_freq;
1436 
1437 	cpufreq_freq_transition_begin(policy, &freqs);
1438 	cpufreq_freq_transition_end(policy, &freqs, 0);
1439 }
1440 
1441 /**
1442  * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1443  * @cpu: CPU number
1444  *
1445  * This is the last known freq, without actually getting it from the driver.
1446  * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1447  */
1448 unsigned int cpufreq_quick_get(unsigned int cpu)
1449 {
1450 	struct cpufreq_policy *policy;
1451 	unsigned int ret_freq = 0;
1452 	unsigned long flags;
1453 
1454 	read_lock_irqsave(&cpufreq_driver_lock, flags);
1455 
1456 	if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1457 		ret_freq = cpufreq_driver->get(cpu);
1458 		read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1459 		return ret_freq;
1460 	}
1461 
1462 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1463 
1464 	policy = cpufreq_cpu_get(cpu);
1465 	if (policy) {
1466 		ret_freq = policy->cur;
1467 		cpufreq_cpu_put(policy);
1468 	}
1469 
1470 	return ret_freq;
1471 }
1472 EXPORT_SYMBOL(cpufreq_quick_get);
1473 
1474 /**
1475  * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1476  * @cpu: CPU number
1477  *
1478  * Just return the max possible frequency for a given CPU.
1479  */
1480 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1481 {
1482 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1483 	unsigned int ret_freq = 0;
1484 
1485 	if (policy) {
1486 		ret_freq = policy->max;
1487 		cpufreq_cpu_put(policy);
1488 	}
1489 
1490 	return ret_freq;
1491 }
1492 EXPORT_SYMBOL(cpufreq_quick_get_max);
1493 
1494 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1495 {
1496 	unsigned int ret_freq = 0;
1497 
1498 	if (!cpufreq_driver->get)
1499 		return ret_freq;
1500 
1501 	ret_freq = cpufreq_driver->get(policy->cpu);
1502 
1503 	/*
1504 	 * Updating inactive policies is invalid, so avoid doing that.  Also
1505 	 * if fast frequency switching is used with the given policy, the check
1506 	 * against policy->cur is pointless, so skip it in that case too.
1507 	 */
1508 	if (unlikely(policy_is_inactive(policy)) || policy->fast_switch_enabled)
1509 		return ret_freq;
1510 
1511 	if (ret_freq && policy->cur &&
1512 		!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1513 		/* verify no discrepancy between actual and
1514 					saved value exists */
1515 		if (unlikely(ret_freq != policy->cur)) {
1516 			cpufreq_out_of_sync(policy, ret_freq);
1517 			schedule_work(&policy->update);
1518 		}
1519 	}
1520 
1521 	return ret_freq;
1522 }
1523 
1524 /**
1525  * cpufreq_get - get the current CPU frequency (in kHz)
1526  * @cpu: CPU number
1527  *
1528  * Get the CPU current (static) CPU frequency
1529  */
1530 unsigned int cpufreq_get(unsigned int cpu)
1531 {
1532 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1533 	unsigned int ret_freq = 0;
1534 
1535 	if (policy) {
1536 		down_read(&policy->rwsem);
1537 
1538 		if (!policy_is_inactive(policy))
1539 			ret_freq = __cpufreq_get(policy);
1540 
1541 		up_read(&policy->rwsem);
1542 
1543 		cpufreq_cpu_put(policy);
1544 	}
1545 
1546 	return ret_freq;
1547 }
1548 EXPORT_SYMBOL(cpufreq_get);
1549 
1550 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1551 {
1552 	unsigned int new_freq;
1553 
1554 	new_freq = cpufreq_driver->get(policy->cpu);
1555 	if (!new_freq)
1556 		return 0;
1557 
1558 	if (!policy->cur) {
1559 		pr_debug("cpufreq: Driver did not initialize current freq\n");
1560 		policy->cur = new_freq;
1561 	} else if (policy->cur != new_freq && has_target()) {
1562 		cpufreq_out_of_sync(policy, new_freq);
1563 	}
1564 
1565 	return new_freq;
1566 }
1567 
1568 static struct subsys_interface cpufreq_interface = {
1569 	.name		= "cpufreq",
1570 	.subsys		= &cpu_subsys,
1571 	.add_dev	= cpufreq_add_dev,
1572 	.remove_dev	= cpufreq_remove_dev,
1573 };
1574 
1575 /*
1576  * In case platform wants some specific frequency to be configured
1577  * during suspend..
1578  */
1579 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1580 {
1581 	int ret;
1582 
1583 	if (!policy->suspend_freq) {
1584 		pr_debug("%s: suspend_freq not defined\n", __func__);
1585 		return 0;
1586 	}
1587 
1588 	pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1589 			policy->suspend_freq);
1590 
1591 	ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1592 			CPUFREQ_RELATION_H);
1593 	if (ret)
1594 		pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1595 				__func__, policy->suspend_freq, ret);
1596 
1597 	return ret;
1598 }
1599 EXPORT_SYMBOL(cpufreq_generic_suspend);
1600 
1601 /**
1602  * cpufreq_suspend() - Suspend CPUFreq governors
1603  *
1604  * Called during system wide Suspend/Hibernate cycles for suspending governors
1605  * as some platforms can't change frequency after this point in suspend cycle.
1606  * Because some of the devices (like: i2c, regulators, etc) they use for
1607  * changing frequency are suspended quickly after this point.
1608  */
1609 void cpufreq_suspend(void)
1610 {
1611 	struct cpufreq_policy *policy;
1612 
1613 	if (!cpufreq_driver)
1614 		return;
1615 
1616 	if (!has_target() && !cpufreq_driver->suspend)
1617 		goto suspend;
1618 
1619 	pr_debug("%s: Suspending Governors\n", __func__);
1620 
1621 	for_each_active_policy(policy) {
1622 		if (has_target()) {
1623 			down_write(&policy->rwsem);
1624 			cpufreq_stop_governor(policy);
1625 			up_write(&policy->rwsem);
1626 		}
1627 
1628 		if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1629 			pr_err("%s: Failed to suspend driver: %p\n", __func__,
1630 				policy);
1631 	}
1632 
1633 suspend:
1634 	cpufreq_suspended = true;
1635 }
1636 
1637 /**
1638  * cpufreq_resume() - Resume CPUFreq governors
1639  *
1640  * Called during system wide Suspend/Hibernate cycle for resuming governors that
1641  * are suspended with cpufreq_suspend().
1642  */
1643 void cpufreq_resume(void)
1644 {
1645 	struct cpufreq_policy *policy;
1646 	int ret;
1647 
1648 	if (!cpufreq_driver)
1649 		return;
1650 
1651 	cpufreq_suspended = false;
1652 
1653 	if (!has_target() && !cpufreq_driver->resume)
1654 		return;
1655 
1656 	pr_debug("%s: Resuming Governors\n", __func__);
1657 
1658 	for_each_active_policy(policy) {
1659 		if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1660 			pr_err("%s: Failed to resume driver: %p\n", __func__,
1661 				policy);
1662 		} else if (has_target()) {
1663 			down_write(&policy->rwsem);
1664 			ret = cpufreq_start_governor(policy);
1665 			up_write(&policy->rwsem);
1666 
1667 			if (ret)
1668 				pr_err("%s: Failed to start governor for policy: %p\n",
1669 				       __func__, policy);
1670 		}
1671 	}
1672 }
1673 
1674 /**
1675  *	cpufreq_get_current_driver - return current driver's name
1676  *
1677  *	Return the name string of the currently loaded cpufreq driver
1678  *	or NULL, if none.
1679  */
1680 const char *cpufreq_get_current_driver(void)
1681 {
1682 	if (cpufreq_driver)
1683 		return cpufreq_driver->name;
1684 
1685 	return NULL;
1686 }
1687 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1688 
1689 /**
1690  *	cpufreq_get_driver_data - return current driver data
1691  *
1692  *	Return the private data of the currently loaded cpufreq
1693  *	driver, or NULL if no cpufreq driver is loaded.
1694  */
1695 void *cpufreq_get_driver_data(void)
1696 {
1697 	if (cpufreq_driver)
1698 		return cpufreq_driver->driver_data;
1699 
1700 	return NULL;
1701 }
1702 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1703 
1704 /*********************************************************************
1705  *                     NOTIFIER LISTS INTERFACE                      *
1706  *********************************************************************/
1707 
1708 /**
1709  *	cpufreq_register_notifier - register a driver with cpufreq
1710  *	@nb: notifier function to register
1711  *      @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1712  *
1713  *	Add a driver to one of two lists: either a list of drivers that
1714  *      are notified about clock rate changes (once before and once after
1715  *      the transition), or a list of drivers that are notified about
1716  *      changes in cpufreq policy.
1717  *
1718  *	This function may sleep, and has the same return conditions as
1719  *	blocking_notifier_chain_register.
1720  */
1721 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1722 {
1723 	int ret;
1724 
1725 	if (cpufreq_disabled())
1726 		return -EINVAL;
1727 
1728 	WARN_ON(!init_cpufreq_transition_notifier_list_called);
1729 
1730 	switch (list) {
1731 	case CPUFREQ_TRANSITION_NOTIFIER:
1732 		mutex_lock(&cpufreq_fast_switch_lock);
1733 
1734 		if (cpufreq_fast_switch_count > 0) {
1735 			mutex_unlock(&cpufreq_fast_switch_lock);
1736 			return -EBUSY;
1737 		}
1738 		ret = srcu_notifier_chain_register(
1739 				&cpufreq_transition_notifier_list, nb);
1740 		if (!ret)
1741 			cpufreq_fast_switch_count--;
1742 
1743 		mutex_unlock(&cpufreq_fast_switch_lock);
1744 		break;
1745 	case CPUFREQ_POLICY_NOTIFIER:
1746 		ret = blocking_notifier_chain_register(
1747 				&cpufreq_policy_notifier_list, nb);
1748 		break;
1749 	default:
1750 		ret = -EINVAL;
1751 	}
1752 
1753 	return ret;
1754 }
1755 EXPORT_SYMBOL(cpufreq_register_notifier);
1756 
1757 /**
1758  *	cpufreq_unregister_notifier - unregister a driver with cpufreq
1759  *	@nb: notifier block to be unregistered
1760  *	@list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1761  *
1762  *	Remove a driver from the CPU frequency notifier list.
1763  *
1764  *	This function may sleep, and has the same return conditions as
1765  *	blocking_notifier_chain_unregister.
1766  */
1767 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1768 {
1769 	int ret;
1770 
1771 	if (cpufreq_disabled())
1772 		return -EINVAL;
1773 
1774 	switch (list) {
1775 	case CPUFREQ_TRANSITION_NOTIFIER:
1776 		mutex_lock(&cpufreq_fast_switch_lock);
1777 
1778 		ret = srcu_notifier_chain_unregister(
1779 				&cpufreq_transition_notifier_list, nb);
1780 		if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1781 			cpufreq_fast_switch_count++;
1782 
1783 		mutex_unlock(&cpufreq_fast_switch_lock);
1784 		break;
1785 	case CPUFREQ_POLICY_NOTIFIER:
1786 		ret = blocking_notifier_chain_unregister(
1787 				&cpufreq_policy_notifier_list, nb);
1788 		break;
1789 	default:
1790 		ret = -EINVAL;
1791 	}
1792 
1793 	return ret;
1794 }
1795 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1796 
1797 
1798 /*********************************************************************
1799  *                              GOVERNORS                            *
1800  *********************************************************************/
1801 
1802 /**
1803  * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1804  * @policy: cpufreq policy to switch the frequency for.
1805  * @target_freq: New frequency to set (may be approximate).
1806  *
1807  * Carry out a fast frequency switch without sleeping.
1808  *
1809  * The driver's ->fast_switch() callback invoked by this function must be
1810  * suitable for being called from within RCU-sched read-side critical sections
1811  * and it is expected to select the minimum available frequency greater than or
1812  * equal to @target_freq (CPUFREQ_RELATION_L).
1813  *
1814  * This function must not be called if policy->fast_switch_enabled is unset.
1815  *
1816  * Governors calling this function must guarantee that it will never be invoked
1817  * twice in parallel for the same policy and that it will never be called in
1818  * parallel with either ->target() or ->target_index() for the same policy.
1819  *
1820  * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()
1821  * callback to indicate an error condition, the hardware configuration must be
1822  * preserved.
1823  */
1824 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1825 					unsigned int target_freq)
1826 {
1827 	target_freq = clamp_val(target_freq, policy->min, policy->max);
1828 
1829 	return cpufreq_driver->fast_switch(policy, target_freq);
1830 }
1831 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1832 
1833 /* Must set freqs->new to intermediate frequency */
1834 static int __target_intermediate(struct cpufreq_policy *policy,
1835 				 struct cpufreq_freqs *freqs, int index)
1836 {
1837 	int ret;
1838 
1839 	freqs->new = cpufreq_driver->get_intermediate(policy, index);
1840 
1841 	/* We don't need to switch to intermediate freq */
1842 	if (!freqs->new)
1843 		return 0;
1844 
1845 	pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1846 		 __func__, policy->cpu, freqs->old, freqs->new);
1847 
1848 	cpufreq_freq_transition_begin(policy, freqs);
1849 	ret = cpufreq_driver->target_intermediate(policy, index);
1850 	cpufreq_freq_transition_end(policy, freqs, ret);
1851 
1852 	if (ret)
1853 		pr_err("%s: Failed to change to intermediate frequency: %d\n",
1854 		       __func__, ret);
1855 
1856 	return ret;
1857 }
1858 
1859 static int __target_index(struct cpufreq_policy *policy, int index)
1860 {
1861 	struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1862 	unsigned int intermediate_freq = 0;
1863 	unsigned int newfreq = policy->freq_table[index].frequency;
1864 	int retval = -EINVAL;
1865 	bool notify;
1866 
1867 	if (newfreq == policy->cur)
1868 		return 0;
1869 
1870 	notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1871 	if (notify) {
1872 		/* Handle switching to intermediate frequency */
1873 		if (cpufreq_driver->get_intermediate) {
1874 			retval = __target_intermediate(policy, &freqs, index);
1875 			if (retval)
1876 				return retval;
1877 
1878 			intermediate_freq = freqs.new;
1879 			/* Set old freq to intermediate */
1880 			if (intermediate_freq)
1881 				freqs.old = freqs.new;
1882 		}
1883 
1884 		freqs.new = newfreq;
1885 		pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1886 			 __func__, policy->cpu, freqs.old, freqs.new);
1887 
1888 		cpufreq_freq_transition_begin(policy, &freqs);
1889 	}
1890 
1891 	retval = cpufreq_driver->target_index(policy, index);
1892 	if (retval)
1893 		pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1894 		       retval);
1895 
1896 	if (notify) {
1897 		cpufreq_freq_transition_end(policy, &freqs, retval);
1898 
1899 		/*
1900 		 * Failed after setting to intermediate freq? Driver should have
1901 		 * reverted back to initial frequency and so should we. Check
1902 		 * here for intermediate_freq instead of get_intermediate, in
1903 		 * case we haven't switched to intermediate freq at all.
1904 		 */
1905 		if (unlikely(retval && intermediate_freq)) {
1906 			freqs.old = intermediate_freq;
1907 			freqs.new = policy->restore_freq;
1908 			cpufreq_freq_transition_begin(policy, &freqs);
1909 			cpufreq_freq_transition_end(policy, &freqs, 0);
1910 		}
1911 	}
1912 
1913 	return retval;
1914 }
1915 
1916 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1917 			    unsigned int target_freq,
1918 			    unsigned int relation)
1919 {
1920 	unsigned int old_target_freq = target_freq;
1921 	int index;
1922 
1923 	if (cpufreq_disabled())
1924 		return -ENODEV;
1925 
1926 	/* Make sure that target_freq is within supported range */
1927 	target_freq = clamp_val(target_freq, policy->min, policy->max);
1928 
1929 	pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1930 		 policy->cpu, target_freq, relation, old_target_freq);
1931 
1932 	/*
1933 	 * This might look like a redundant call as we are checking it again
1934 	 * after finding index. But it is left intentionally for cases where
1935 	 * exactly same freq is called again and so we can save on few function
1936 	 * calls.
1937 	 */
1938 	if (target_freq == policy->cur)
1939 		return 0;
1940 
1941 	/* Save last value to restore later on errors */
1942 	policy->restore_freq = policy->cur;
1943 
1944 	if (cpufreq_driver->target)
1945 		return cpufreq_driver->target(policy, target_freq, relation);
1946 
1947 	if (!cpufreq_driver->target_index)
1948 		return -EINVAL;
1949 
1950 	index = cpufreq_frequency_table_target(policy, target_freq, relation);
1951 
1952 	return __target_index(policy, index);
1953 }
1954 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1955 
1956 int cpufreq_driver_target(struct cpufreq_policy *policy,
1957 			  unsigned int target_freq,
1958 			  unsigned int relation)
1959 {
1960 	int ret = -EINVAL;
1961 
1962 	down_write(&policy->rwsem);
1963 
1964 	ret = __cpufreq_driver_target(policy, target_freq, relation);
1965 
1966 	up_write(&policy->rwsem);
1967 
1968 	return ret;
1969 }
1970 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1971 
1972 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1973 {
1974 	return NULL;
1975 }
1976 
1977 static int cpufreq_init_governor(struct cpufreq_policy *policy)
1978 {
1979 	int ret;
1980 
1981 	/* Don't start any governor operations if we are entering suspend */
1982 	if (cpufreq_suspended)
1983 		return 0;
1984 	/*
1985 	 * Governor might not be initiated here if ACPI _PPC changed
1986 	 * notification happened, so check it.
1987 	 */
1988 	if (!policy->governor)
1989 		return -EINVAL;
1990 
1991 	if (policy->governor->max_transition_latency &&
1992 	    policy->cpuinfo.transition_latency >
1993 	    policy->governor->max_transition_latency) {
1994 		struct cpufreq_governor *gov = cpufreq_fallback_governor();
1995 
1996 		if (gov) {
1997 			pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1998 				policy->governor->name, gov->name);
1999 			policy->governor = gov;
2000 		} else {
2001 			return -EINVAL;
2002 		}
2003 	}
2004 
2005 	if (!try_module_get(policy->governor->owner))
2006 		return -EINVAL;
2007 
2008 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2009 
2010 	if (policy->governor->init) {
2011 		ret = policy->governor->init(policy);
2012 		if (ret) {
2013 			module_put(policy->governor->owner);
2014 			return ret;
2015 		}
2016 	}
2017 
2018 	return 0;
2019 }
2020 
2021 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2022 {
2023 	if (cpufreq_suspended || !policy->governor)
2024 		return;
2025 
2026 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2027 
2028 	if (policy->governor->exit)
2029 		policy->governor->exit(policy);
2030 
2031 	module_put(policy->governor->owner);
2032 }
2033 
2034 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2035 {
2036 	int ret;
2037 
2038 	if (cpufreq_suspended)
2039 		return 0;
2040 
2041 	if (!policy->governor)
2042 		return -EINVAL;
2043 
2044 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2045 
2046 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2047 		cpufreq_update_current_freq(policy);
2048 
2049 	if (policy->governor->start) {
2050 		ret = policy->governor->start(policy);
2051 		if (ret)
2052 			return ret;
2053 	}
2054 
2055 	if (policy->governor->limits)
2056 		policy->governor->limits(policy);
2057 
2058 	return 0;
2059 }
2060 
2061 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2062 {
2063 	if (cpufreq_suspended || !policy->governor)
2064 		return;
2065 
2066 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2067 
2068 	if (policy->governor->stop)
2069 		policy->governor->stop(policy);
2070 }
2071 
2072 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2073 {
2074 	if (cpufreq_suspended || !policy->governor)
2075 		return;
2076 
2077 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2078 
2079 	if (policy->governor->limits)
2080 		policy->governor->limits(policy);
2081 }
2082 
2083 int cpufreq_register_governor(struct cpufreq_governor *governor)
2084 {
2085 	int err;
2086 
2087 	if (!governor)
2088 		return -EINVAL;
2089 
2090 	if (cpufreq_disabled())
2091 		return -ENODEV;
2092 
2093 	mutex_lock(&cpufreq_governor_mutex);
2094 
2095 	err = -EBUSY;
2096 	if (!find_governor(governor->name)) {
2097 		err = 0;
2098 		list_add(&governor->governor_list, &cpufreq_governor_list);
2099 	}
2100 
2101 	mutex_unlock(&cpufreq_governor_mutex);
2102 	return err;
2103 }
2104 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2105 
2106 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2107 {
2108 	struct cpufreq_policy *policy;
2109 	unsigned long flags;
2110 
2111 	if (!governor)
2112 		return;
2113 
2114 	if (cpufreq_disabled())
2115 		return;
2116 
2117 	/* clear last_governor for all inactive policies */
2118 	read_lock_irqsave(&cpufreq_driver_lock, flags);
2119 	for_each_inactive_policy(policy) {
2120 		if (!strcmp(policy->last_governor, governor->name)) {
2121 			policy->governor = NULL;
2122 			strcpy(policy->last_governor, "\0");
2123 		}
2124 	}
2125 	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2126 
2127 	mutex_lock(&cpufreq_governor_mutex);
2128 	list_del(&governor->governor_list);
2129 	mutex_unlock(&cpufreq_governor_mutex);
2130 	return;
2131 }
2132 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2133 
2134 
2135 /*********************************************************************
2136  *                          POLICY INTERFACE                         *
2137  *********************************************************************/
2138 
2139 /**
2140  * cpufreq_get_policy - get the current cpufreq_policy
2141  * @policy: struct cpufreq_policy into which the current cpufreq_policy
2142  *	is written
2143  *
2144  * Reads the current cpufreq policy.
2145  */
2146 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2147 {
2148 	struct cpufreq_policy *cpu_policy;
2149 	if (!policy)
2150 		return -EINVAL;
2151 
2152 	cpu_policy = cpufreq_cpu_get(cpu);
2153 	if (!cpu_policy)
2154 		return -EINVAL;
2155 
2156 	memcpy(policy, cpu_policy, sizeof(*policy));
2157 
2158 	cpufreq_cpu_put(cpu_policy);
2159 	return 0;
2160 }
2161 EXPORT_SYMBOL(cpufreq_get_policy);
2162 
2163 /*
2164  * policy : current policy.
2165  * new_policy: policy to be set.
2166  */
2167 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2168 				struct cpufreq_policy *new_policy)
2169 {
2170 	struct cpufreq_governor *old_gov;
2171 	int ret;
2172 
2173 	pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2174 		 new_policy->cpu, new_policy->min, new_policy->max);
2175 
2176 	memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2177 
2178 	/*
2179 	* This check works well when we store new min/max freq attributes,
2180 	* because new_policy is a copy of policy with one field updated.
2181 	*/
2182 	if (new_policy->min > new_policy->max)
2183 		return -EINVAL;
2184 
2185 	/* verify the cpu speed can be set within this limit */
2186 	ret = cpufreq_driver->verify(new_policy);
2187 	if (ret)
2188 		return ret;
2189 
2190 	/* adjust if necessary - all reasons */
2191 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2192 			CPUFREQ_ADJUST, new_policy);
2193 
2194 	/*
2195 	 * verify the cpu speed can be set within this limit, which might be
2196 	 * different to the first one
2197 	 */
2198 	ret = cpufreq_driver->verify(new_policy);
2199 	if (ret)
2200 		return ret;
2201 
2202 	/* notification of the new policy */
2203 	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2204 			CPUFREQ_NOTIFY, new_policy);
2205 
2206 	policy->min = new_policy->min;
2207 	policy->max = new_policy->max;
2208 
2209 	policy->cached_target_freq = UINT_MAX;
2210 
2211 	pr_debug("new min and max freqs are %u - %u kHz\n",
2212 		 policy->min, policy->max);
2213 
2214 	if (cpufreq_driver->setpolicy) {
2215 		policy->policy = new_policy->policy;
2216 		pr_debug("setting range\n");
2217 		return cpufreq_driver->setpolicy(new_policy);
2218 	}
2219 
2220 	if (new_policy->governor == policy->governor) {
2221 		pr_debug("cpufreq: governor limits update\n");
2222 		cpufreq_governor_limits(policy);
2223 		return 0;
2224 	}
2225 
2226 	pr_debug("governor switch\n");
2227 
2228 	/* save old, working values */
2229 	old_gov = policy->governor;
2230 	/* end old governor */
2231 	if (old_gov) {
2232 		cpufreq_stop_governor(policy);
2233 		cpufreq_exit_governor(policy);
2234 	}
2235 
2236 	/* start new governor */
2237 	policy->governor = new_policy->governor;
2238 	ret = cpufreq_init_governor(policy);
2239 	if (!ret) {
2240 		ret = cpufreq_start_governor(policy);
2241 		if (!ret) {
2242 			pr_debug("cpufreq: governor change\n");
2243 			return 0;
2244 		}
2245 		cpufreq_exit_governor(policy);
2246 	}
2247 
2248 	/* new governor failed, so re-start old one */
2249 	pr_debug("starting governor %s failed\n", policy->governor->name);
2250 	if (old_gov) {
2251 		policy->governor = old_gov;
2252 		if (cpufreq_init_governor(policy))
2253 			policy->governor = NULL;
2254 		else
2255 			cpufreq_start_governor(policy);
2256 	}
2257 
2258 	return ret;
2259 }
2260 
2261 /**
2262  *	cpufreq_update_policy - re-evaluate an existing cpufreq policy
2263  *	@cpu: CPU which shall be re-evaluated
2264  *
2265  *	Useful for policy notifiers which have different necessities
2266  *	at different times.
2267  */
2268 void cpufreq_update_policy(unsigned int cpu)
2269 {
2270 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2271 	struct cpufreq_policy new_policy;
2272 
2273 	if (!policy)
2274 		return;
2275 
2276 	down_write(&policy->rwsem);
2277 
2278 	if (policy_is_inactive(policy))
2279 		goto unlock;
2280 
2281 	pr_debug("updating policy for CPU %u\n", cpu);
2282 	memcpy(&new_policy, policy, sizeof(*policy));
2283 	new_policy.min = policy->user_policy.min;
2284 	new_policy.max = policy->user_policy.max;
2285 
2286 	/*
2287 	 * BIOS might change freq behind our back
2288 	 * -> ask driver for current freq and notify governors about a change
2289 	 */
2290 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2291 		if (cpufreq_suspended)
2292 			goto unlock;
2293 
2294 		new_policy.cur = cpufreq_update_current_freq(policy);
2295 		if (WARN_ON(!new_policy.cur))
2296 			goto unlock;
2297 	}
2298 
2299 	cpufreq_set_policy(policy, &new_policy);
2300 
2301 unlock:
2302 	up_write(&policy->rwsem);
2303 
2304 	cpufreq_cpu_put(policy);
2305 }
2306 EXPORT_SYMBOL(cpufreq_update_policy);
2307 
2308 /*********************************************************************
2309  *               BOOST						     *
2310  *********************************************************************/
2311 static int cpufreq_boost_set_sw(int state)
2312 {
2313 	struct cpufreq_policy *policy;
2314 	int ret = -EINVAL;
2315 
2316 	for_each_active_policy(policy) {
2317 		if (!policy->freq_table)
2318 			continue;
2319 
2320 		ret = cpufreq_frequency_table_cpuinfo(policy,
2321 						      policy->freq_table);
2322 		if (ret) {
2323 			pr_err("%s: Policy frequency update failed\n",
2324 			       __func__);
2325 			break;
2326 		}
2327 
2328 		down_write(&policy->rwsem);
2329 		policy->user_policy.max = policy->max;
2330 		cpufreq_governor_limits(policy);
2331 		up_write(&policy->rwsem);
2332 	}
2333 
2334 	return ret;
2335 }
2336 
2337 int cpufreq_boost_trigger_state(int state)
2338 {
2339 	unsigned long flags;
2340 	int ret = 0;
2341 
2342 	if (cpufreq_driver->boost_enabled == state)
2343 		return 0;
2344 
2345 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2346 	cpufreq_driver->boost_enabled = state;
2347 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2348 
2349 	ret = cpufreq_driver->set_boost(state);
2350 	if (ret) {
2351 		write_lock_irqsave(&cpufreq_driver_lock, flags);
2352 		cpufreq_driver->boost_enabled = !state;
2353 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2354 
2355 		pr_err("%s: Cannot %s BOOST\n",
2356 		       __func__, state ? "enable" : "disable");
2357 	}
2358 
2359 	return ret;
2360 }
2361 
2362 static bool cpufreq_boost_supported(void)
2363 {
2364 	return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2365 }
2366 
2367 static int create_boost_sysfs_file(void)
2368 {
2369 	int ret;
2370 
2371 	ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2372 	if (ret)
2373 		pr_err("%s: cannot register global BOOST sysfs file\n",
2374 		       __func__);
2375 
2376 	return ret;
2377 }
2378 
2379 static void remove_boost_sysfs_file(void)
2380 {
2381 	if (cpufreq_boost_supported())
2382 		sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2383 }
2384 
2385 int cpufreq_enable_boost_support(void)
2386 {
2387 	if (!cpufreq_driver)
2388 		return -EINVAL;
2389 
2390 	if (cpufreq_boost_supported())
2391 		return 0;
2392 
2393 	cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2394 
2395 	/* This will get removed on driver unregister */
2396 	return create_boost_sysfs_file();
2397 }
2398 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2399 
2400 int cpufreq_boost_enabled(void)
2401 {
2402 	return cpufreq_driver->boost_enabled;
2403 }
2404 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2405 
2406 /*********************************************************************
2407  *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
2408  *********************************************************************/
2409 static enum cpuhp_state hp_online;
2410 
2411 static int cpuhp_cpufreq_online(unsigned int cpu)
2412 {
2413 	cpufreq_online(cpu);
2414 
2415 	return 0;
2416 }
2417 
2418 static int cpuhp_cpufreq_offline(unsigned int cpu)
2419 {
2420 	cpufreq_offline(cpu);
2421 
2422 	return 0;
2423 }
2424 
2425 /**
2426  * cpufreq_register_driver - register a CPU Frequency driver
2427  * @driver_data: A struct cpufreq_driver containing the values#
2428  * submitted by the CPU Frequency driver.
2429  *
2430  * Registers a CPU Frequency driver to this core code. This code
2431  * returns zero on success, -EEXIST when another driver got here first
2432  * (and isn't unregistered in the meantime).
2433  *
2434  */
2435 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2436 {
2437 	unsigned long flags;
2438 	int ret;
2439 
2440 	if (cpufreq_disabled())
2441 		return -ENODEV;
2442 
2443 	if (!driver_data || !driver_data->verify || !driver_data->init ||
2444 	    !(driver_data->setpolicy || driver_data->target_index ||
2445 		    driver_data->target) ||
2446 	     (driver_data->setpolicy && (driver_data->target_index ||
2447 		    driver_data->target)) ||
2448 	     (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2449 		return -EINVAL;
2450 
2451 	pr_debug("trying to register driver %s\n", driver_data->name);
2452 
2453 	/* Protect against concurrent CPU online/offline. */
2454 	cpus_read_lock();
2455 
2456 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2457 	if (cpufreq_driver) {
2458 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2459 		ret = -EEXIST;
2460 		goto out;
2461 	}
2462 	cpufreq_driver = driver_data;
2463 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2464 
2465 	if (driver_data->setpolicy)
2466 		driver_data->flags |= CPUFREQ_CONST_LOOPS;
2467 
2468 	if (cpufreq_boost_supported()) {
2469 		ret = create_boost_sysfs_file();
2470 		if (ret)
2471 			goto err_null_driver;
2472 	}
2473 
2474 	ret = subsys_interface_register(&cpufreq_interface);
2475 	if (ret)
2476 		goto err_boost_unreg;
2477 
2478 	if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2479 	    list_empty(&cpufreq_policy_list)) {
2480 		/* if all ->init() calls failed, unregister */
2481 		ret = -ENODEV;
2482 		pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2483 			 driver_data->name);
2484 		goto err_if_unreg;
2485 	}
2486 
2487 	ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2488 						   "cpufreq:online",
2489 						   cpuhp_cpufreq_online,
2490 						   cpuhp_cpufreq_offline);
2491 	if (ret < 0)
2492 		goto err_if_unreg;
2493 	hp_online = ret;
2494 	ret = 0;
2495 
2496 	pr_debug("driver %s up and running\n", driver_data->name);
2497 	goto out;
2498 
2499 err_if_unreg:
2500 	subsys_interface_unregister(&cpufreq_interface);
2501 err_boost_unreg:
2502 	remove_boost_sysfs_file();
2503 err_null_driver:
2504 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2505 	cpufreq_driver = NULL;
2506 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2507 out:
2508 	cpus_read_unlock();
2509 	return ret;
2510 }
2511 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2512 
2513 /**
2514  * cpufreq_unregister_driver - unregister the current CPUFreq driver
2515  *
2516  * Unregister the current CPUFreq driver. Only call this if you have
2517  * the right to do so, i.e. if you have succeeded in initialising before!
2518  * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2519  * currently not initialised.
2520  */
2521 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2522 {
2523 	unsigned long flags;
2524 
2525 	if (!cpufreq_driver || (driver != cpufreq_driver))
2526 		return -EINVAL;
2527 
2528 	pr_debug("unregistering driver %s\n", driver->name);
2529 
2530 	/* Protect against concurrent cpu hotplug */
2531 	cpus_read_lock();
2532 	subsys_interface_unregister(&cpufreq_interface);
2533 	remove_boost_sysfs_file();
2534 	cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2535 
2536 	write_lock_irqsave(&cpufreq_driver_lock, flags);
2537 
2538 	cpufreq_driver = NULL;
2539 
2540 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2541 	cpus_read_unlock();
2542 
2543 	return 0;
2544 }
2545 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2546 
2547 /*
2548  * Stop cpufreq at shutdown to make sure it isn't holding any locks
2549  * or mutexes when secondary CPUs are halted.
2550  */
2551 static struct syscore_ops cpufreq_syscore_ops = {
2552 	.shutdown = cpufreq_suspend,
2553 };
2554 
2555 struct kobject *cpufreq_global_kobject;
2556 EXPORT_SYMBOL(cpufreq_global_kobject);
2557 
2558 static int __init cpufreq_core_init(void)
2559 {
2560 	if (cpufreq_disabled())
2561 		return -ENODEV;
2562 
2563 	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2564 	BUG_ON(!cpufreq_global_kobject);
2565 
2566 	register_syscore_ops(&cpufreq_syscore_ops);
2567 
2568 	return 0;
2569 }
2570 module_param(off, int, 0444);
2571 core_initcall(cpufreq_core_init);
2572