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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/cpufreq/cpufreq.c
4 *
5 * Copyright (C) 2001 Russell King
6 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 *
9 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
10 * Added handling for CPU hotplug
11 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
12 * Fix handling for CPU hotplug -- affected CPUs
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/cpu.h>
18#include <linux/cpufreq.h>
19#include <linux/cpu_cooling.h>
20#include <linux/delay.h>
21#include <linux/device.h>
22#include <linux/init.h>
23#include <linux/kernel_stat.h>
24#include <linux/module.h>
25#include <linux/mutex.h>
26#include <linux/pm_qos.h>
27#include <linux/slab.h>
28#include <linux/suspend.h>
29#include <linux/syscore_ops.h>
30#include <linux/tick.h>
31#include <linux/units.h>
32#include <trace/events/power.h>
33
34static LIST_HEAD(cpufreq_policy_list);
35
36/* Macros to iterate over CPU policies */
37#define for_each_suitable_policy(__policy, __active) \
38 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
39 if ((__active) == !policy_is_inactive(__policy))
40
41#define for_each_active_policy(__policy) \
42 for_each_suitable_policy(__policy, true)
43#define for_each_inactive_policy(__policy) \
44 for_each_suitable_policy(__policy, false)
45
46/* Iterate over governors */
47static LIST_HEAD(cpufreq_governor_list);
48#define for_each_governor(__governor) \
49 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
50
51static char default_governor[CPUFREQ_NAME_LEN];
52
53/*
54 * The "cpufreq driver" - the arch- or hardware-dependent low
55 * level driver of CPUFreq support, and its spinlock. This lock
56 * also protects the cpufreq_cpu_data array.
57 */
58static struct cpufreq_driver *cpufreq_driver;
59static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
60static DEFINE_RWLOCK(cpufreq_driver_lock);
61
62static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
63bool cpufreq_supports_freq_invariance(void)
64{
65 return static_branch_likely(&cpufreq_freq_invariance);
66}
67
68/* Flag to suspend/resume CPUFreq governors */
69static bool cpufreq_suspended;
70
71static inline bool has_target(void)
72{
73 return cpufreq_driver->target_index || cpufreq_driver->target;
74}
75
76bool has_target_index(void)
77{
78 return !!cpufreq_driver->target_index;
79}
80
81/* internal prototypes */
82static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
83static int cpufreq_init_governor(struct cpufreq_policy *policy);
84static void cpufreq_exit_governor(struct cpufreq_policy *policy);
85static void cpufreq_governor_limits(struct cpufreq_policy *policy);
86static int cpufreq_set_policy(struct cpufreq_policy *policy,
87 struct cpufreq_governor *new_gov,
88 unsigned int new_pol);
89static bool cpufreq_boost_supported(void);
90
91/*
92 * Two notifier lists: the "policy" list is involved in the
93 * validation process for a new CPU frequency policy; the
94 * "transition" list for kernel code that needs to handle
95 * changes to devices when the CPU clock speed changes.
96 * The mutex locks both lists.
97 */
98static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
99SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
100
101static int off __read_mostly;
102static int cpufreq_disabled(void)
103{
104 return off;
105}
106void disable_cpufreq(void)
107{
108 off = 1;
109}
110static DEFINE_MUTEX(cpufreq_governor_mutex);
111
112bool have_governor_per_policy(void)
113{
114 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
115}
116EXPORT_SYMBOL_GPL(have_governor_per_policy);
117
118static struct kobject *cpufreq_global_kobject;
119
120struct 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}
127EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
128
129static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
130{
131 struct kernel_cpustat kcpustat;
132 u64 cur_wall_time;
133 u64 idle_time;
134 u64 busy_time;
135
136 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
137
138 kcpustat_cpu_fetch(&kcpustat, cpu);
139
140 busy_time = kcpustat.cpustat[CPUTIME_USER];
141 busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
142 busy_time += kcpustat.cpustat[CPUTIME_IRQ];
143 busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
144 busy_time += kcpustat.cpustat[CPUTIME_STEAL];
145 busy_time += kcpustat.cpustat[CPUTIME_NICE];
146
147 idle_time = cur_wall_time - busy_time;
148 if (wall)
149 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
150
151 return div_u64(idle_time, NSEC_PER_USEC);
152}
153
154u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
155{
156 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
157
158 if (idle_time == -1ULL)
159 return get_cpu_idle_time_jiffy(cpu, wall);
160 else if (!io_busy)
161 idle_time += get_cpu_iowait_time_us(cpu, wall);
162
163 return idle_time;
164}
165EXPORT_SYMBOL_GPL(get_cpu_idle_time);
166
167/*
168 * This is a generic cpufreq init() routine which can be used by cpufreq
169 * drivers of SMP systems. It will do following:
170 * - validate & show freq table passed
171 * - set policies transition latency
172 * - policy->cpus with all possible CPUs
173 */
174void cpufreq_generic_init(struct cpufreq_policy *policy,
175 struct cpufreq_frequency_table *table,
176 unsigned int transition_latency)
177{
178 policy->freq_table = table;
179 policy->cpuinfo.transition_latency = transition_latency;
180
181 /*
182 * The driver only supports the SMP configuration where all processors
183 * share the clock and voltage and clock.
184 */
185 cpumask_setall(policy->cpus);
186}
187EXPORT_SYMBOL_GPL(cpufreq_generic_init);
188
189struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
190{
191 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
192
193 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
194}
195EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
196
197unsigned int cpufreq_generic_get(unsigned int cpu)
198{
199 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
200
201 if (!policy || IS_ERR(policy->clk)) {
202 pr_err("%s: No %s associated to cpu: %d\n",
203 __func__, policy ? "clk" : "policy", cpu);
204 return 0;
205 }
206
207 return clk_get_rate(policy->clk) / 1000;
208}
209EXPORT_SYMBOL_GPL(cpufreq_generic_get);
210
211/**
212 * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
213 * @cpu: CPU to find the policy for.
214 *
215 * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
216 * the kobject reference counter of that policy. Return a valid policy on
217 * success or NULL on failure.
218 *
219 * The policy returned by this function has to be released with the help of
220 * cpufreq_cpu_put() to balance its kobject reference counter properly.
221 */
222struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
223{
224 struct cpufreq_policy *policy = NULL;
225 unsigned long flags;
226
227 if (WARN_ON(cpu >= nr_cpu_ids))
228 return NULL;
229
230 /* get the cpufreq driver */
231 read_lock_irqsave(&cpufreq_driver_lock, flags);
232
233 if (cpufreq_driver) {
234 /* get the CPU */
235 policy = cpufreq_cpu_get_raw(cpu);
236 if (policy)
237 kobject_get(&policy->kobj);
238 }
239
240 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
241
242 return policy;
243}
244EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
245
246/**
247 * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
248 * @policy: cpufreq policy returned by cpufreq_cpu_get().
249 */
250void cpufreq_cpu_put(struct cpufreq_policy *policy)
251{
252 kobject_put(&policy->kobj);
253}
254EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
255
256/**
257 * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
258 * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
259 */
260void cpufreq_cpu_release(struct cpufreq_policy *policy)
261{
262 if (WARN_ON(!policy))
263 return;
264
265 lockdep_assert_held(&policy->rwsem);
266
267 up_write(&policy->rwsem);
268
269 cpufreq_cpu_put(policy);
270}
271
272/**
273 * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
274 * @cpu: CPU to find the policy for.
275 *
276 * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
277 * if the policy returned by it is not NULL, acquire its rwsem for writing.
278 * Return the policy if it is active or release it and return NULL otherwise.
279 *
280 * The policy returned by this function has to be released with the help of
281 * cpufreq_cpu_release() in order to release its rwsem and balance its usage
282 * counter properly.
283 */
284struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
285{
286 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
287
288 if (!policy)
289 return NULL;
290
291 down_write(&policy->rwsem);
292
293 if (policy_is_inactive(policy)) {
294 cpufreq_cpu_release(policy);
295 return NULL;
296 }
297
298 return policy;
299}
300
301/*********************************************************************
302 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
303 *********************************************************************/
304
305/**
306 * adjust_jiffies - Adjust the system "loops_per_jiffy".
307 * @val: CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
308 * @ci: Frequency change information.
309 *
310 * This function alters the system "loops_per_jiffy" for the clock
311 * speed change. Note that loops_per_jiffy cannot be updated on SMP
312 * systems as each CPU might be scaled differently. So, use the arch
313 * per-CPU loops_per_jiffy value wherever possible.
314 */
315static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
316{
317#ifndef CONFIG_SMP
318 static unsigned long l_p_j_ref;
319 static unsigned int l_p_j_ref_freq;
320
321 if (ci->flags & CPUFREQ_CONST_LOOPS)
322 return;
323
324 if (!l_p_j_ref_freq) {
325 l_p_j_ref = loops_per_jiffy;
326 l_p_j_ref_freq = ci->old;
327 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
328 l_p_j_ref, l_p_j_ref_freq);
329 }
330 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
331 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
332 ci->new);
333 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
334 loops_per_jiffy, ci->new);
335 }
336#endif
337}
338
339/**
340 * cpufreq_notify_transition - Notify frequency transition and adjust jiffies.
341 * @policy: cpufreq policy to enable fast frequency switching for.
342 * @freqs: contain details of the frequency update.
343 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
344 *
345 * This function calls the transition notifiers and adjust_jiffies().
346 *
347 * It is called twice on all CPU frequency changes that have external effects.
348 */
349static void cpufreq_notify_transition(struct cpufreq_policy *policy,
350 struct cpufreq_freqs *freqs,
351 unsigned int state)
352{
353 int cpu;
354
355 BUG_ON(irqs_disabled());
356
357 if (cpufreq_disabled())
358 return;
359
360 freqs->policy = policy;
361 freqs->flags = cpufreq_driver->flags;
362 pr_debug("notification %u of frequency transition to %u kHz\n",
363 state, freqs->new);
364
365 switch (state) {
366 case CPUFREQ_PRECHANGE:
367 /*
368 * Detect if the driver reported a value as "old frequency"
369 * which is not equal to what the cpufreq core thinks is
370 * "old frequency".
371 */
372 if (policy->cur && policy->cur != freqs->old) {
373 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
374 freqs->old, policy->cur);
375 freqs->old = policy->cur;
376 }
377
378 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
379 CPUFREQ_PRECHANGE, freqs);
380
381 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
382 break;
383
384 case CPUFREQ_POSTCHANGE:
385 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
386 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
387 cpumask_pr_args(policy->cpus));
388
389 for_each_cpu(cpu, policy->cpus)
390 trace_cpu_frequency(freqs->new, cpu);
391
392 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
393 CPUFREQ_POSTCHANGE, freqs);
394
395 cpufreq_stats_record_transition(policy, freqs->new);
396 policy->cur = freqs->new;
397 }
398}
399
400/* Do post notifications when there are chances that transition has failed */
401static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
402 struct cpufreq_freqs *freqs, int transition_failed)
403{
404 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
405 if (!transition_failed)
406 return;
407
408 swap(freqs->old, freqs->new);
409 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
410 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
411}
412
413void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
414 struct cpufreq_freqs *freqs)
415{
416
417 /*
418 * Catch double invocations of _begin() which lead to self-deadlock.
419 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
420 * doesn't invoke _begin() on their behalf, and hence the chances of
421 * double invocations are very low. Moreover, there are scenarios
422 * where these checks can emit false-positive warnings in these
423 * drivers; so we avoid that by skipping them altogether.
424 */
425 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
426 && current == policy->transition_task);
427
428wait:
429 wait_event(policy->transition_wait, !policy->transition_ongoing);
430
431 spin_lock(&policy->transition_lock);
432
433 if (unlikely(policy->transition_ongoing)) {
434 spin_unlock(&policy->transition_lock);
435 goto wait;
436 }
437
438 policy->transition_ongoing = true;
439 policy->transition_task = current;
440
441 spin_unlock(&policy->transition_lock);
442
443 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
444}
445EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
446
447void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
448 struct cpufreq_freqs *freqs, int transition_failed)
449{
450 if (WARN_ON(!policy->transition_ongoing))
451 return;
452
453 cpufreq_notify_post_transition(policy, freqs, transition_failed);
454
455 arch_set_freq_scale(policy->related_cpus,
456 policy->cur,
457 arch_scale_freq_ref(policy->cpu));
458
459 spin_lock(&policy->transition_lock);
460 policy->transition_ongoing = false;
461 policy->transition_task = NULL;
462 spin_unlock(&policy->transition_lock);
463
464 wake_up(&policy->transition_wait);
465}
466EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
467
468/*
469 * Fast frequency switching status count. Positive means "enabled", negative
470 * means "disabled" and 0 means "not decided yet".
471 */
472static int cpufreq_fast_switch_count;
473static DEFINE_MUTEX(cpufreq_fast_switch_lock);
474
475static void cpufreq_list_transition_notifiers(void)
476{
477 struct notifier_block *nb;
478
479 pr_info("Registered transition notifiers:\n");
480
481 mutex_lock(&cpufreq_transition_notifier_list.mutex);
482
483 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
484 pr_info("%pS\n", nb->notifier_call);
485
486 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
487}
488
489/**
490 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
491 * @policy: cpufreq policy to enable fast frequency switching for.
492 *
493 * Try to enable fast frequency switching for @policy.
494 *
495 * The attempt will fail if there is at least one transition notifier registered
496 * at this point, as fast frequency switching is quite fundamentally at odds
497 * with transition notifiers. Thus if successful, it will make registration of
498 * transition notifiers fail going forward.
499 */
500void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
501{
502 lockdep_assert_held(&policy->rwsem);
503
504 if (!policy->fast_switch_possible)
505 return;
506
507 mutex_lock(&cpufreq_fast_switch_lock);
508 if (cpufreq_fast_switch_count >= 0) {
509 cpufreq_fast_switch_count++;
510 policy->fast_switch_enabled = true;
511 } else {
512 pr_warn("CPU%u: Fast frequency switching not enabled\n",
513 policy->cpu);
514 cpufreq_list_transition_notifiers();
515 }
516 mutex_unlock(&cpufreq_fast_switch_lock);
517}
518EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
519
520/**
521 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
522 * @policy: cpufreq policy to disable fast frequency switching for.
523 */
524void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
525{
526 mutex_lock(&cpufreq_fast_switch_lock);
527 if (policy->fast_switch_enabled) {
528 policy->fast_switch_enabled = false;
529 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
530 cpufreq_fast_switch_count--;
531 }
532 mutex_unlock(&cpufreq_fast_switch_lock);
533}
534EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
535
536static unsigned int __resolve_freq(struct cpufreq_policy *policy,
537 unsigned int target_freq, unsigned int relation)
538{
539 unsigned int idx;
540
541 target_freq = clamp_val(target_freq, policy->min, policy->max);
542
543 if (!policy->freq_table)
544 return target_freq;
545
546 idx = cpufreq_frequency_table_target(policy, target_freq, relation);
547 policy->cached_resolved_idx = idx;
548 policy->cached_target_freq = target_freq;
549 return policy->freq_table[idx].frequency;
550}
551
552/**
553 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
554 * one.
555 * @policy: associated policy to interrogate
556 * @target_freq: target frequency to resolve.
557 *
558 * The target to driver frequency mapping is cached in the policy.
559 *
560 * Return: Lowest driver-supported frequency greater than or equal to the
561 * given target_freq, subject to policy (min/max) and driver limitations.
562 */
563unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
564 unsigned int target_freq)
565{
566 return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_LE);
567}
568EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
569
570unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
571{
572 unsigned int latency;
573
574 if (policy->transition_delay_us)
575 return policy->transition_delay_us;
576
577 latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
578 if (latency) {
579 /*
580 * For platforms that can change the frequency very fast (< 10
581 * us), the above formula gives a decent transition delay. But
582 * for platforms where transition_latency is in milliseconds, it
583 * ends up giving unrealistic values.
584 *
585 * Cap the default transition delay to 10 ms, which seems to be
586 * a reasonable amount of time after which we should reevaluate
587 * the frequency.
588 */
589 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
590 }
591
592 return LATENCY_MULTIPLIER;
593}
594EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
595
596/*********************************************************************
597 * SYSFS INTERFACE *
598 *********************************************************************/
599static ssize_t show_boost(struct kobject *kobj,
600 struct kobj_attribute *attr, char *buf)
601{
602 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
603}
604
605static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
606 const char *buf, size_t count)
607{
608 int ret, enable;
609
610 ret = sscanf(buf, "%d", &enable);
611 if (ret != 1 || enable < 0 || enable > 1)
612 return -EINVAL;
613
614 if (cpufreq_boost_trigger_state(enable)) {
615 pr_err("%s: Cannot %s BOOST!\n",
616 __func__, enable ? "enable" : "disable");
617 return -EINVAL;
618 }
619
620 pr_debug("%s: cpufreq BOOST %s\n",
621 __func__, enable ? "enabled" : "disabled");
622
623 return count;
624}
625define_one_global_rw(boost);
626
627static ssize_t show_local_boost(struct cpufreq_policy *policy, char *buf)
628{
629 return sysfs_emit(buf, "%d\n", policy->boost_enabled);
630}
631
632static ssize_t store_local_boost(struct cpufreq_policy *policy,
633 const char *buf, size_t count)
634{
635 int ret, enable;
636
637 ret = kstrtoint(buf, 10, &enable);
638 if (ret || enable < 0 || enable > 1)
639 return -EINVAL;
640
641 if (!cpufreq_driver->boost_enabled)
642 return -EINVAL;
643
644 if (policy->boost_enabled == enable)
645 return count;
646
647 cpus_read_lock();
648 ret = cpufreq_driver->set_boost(policy, enable);
649 cpus_read_unlock();
650
651 if (ret)
652 return ret;
653
654 policy->boost_enabled = enable;
655
656 return count;
657}
658
659static struct freq_attr local_boost = __ATTR(boost, 0644, show_local_boost, store_local_boost);
660
661static struct cpufreq_governor *find_governor(const char *str_governor)
662{
663 struct cpufreq_governor *t;
664
665 for_each_governor(t)
666 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
667 return t;
668
669 return NULL;
670}
671
672static struct cpufreq_governor *get_governor(const char *str_governor)
673{
674 struct cpufreq_governor *t;
675
676 mutex_lock(&cpufreq_governor_mutex);
677 t = find_governor(str_governor);
678 if (!t)
679 goto unlock;
680
681 if (!try_module_get(t->owner))
682 t = NULL;
683
684unlock:
685 mutex_unlock(&cpufreq_governor_mutex);
686
687 return t;
688}
689
690static unsigned int cpufreq_parse_policy(char *str_governor)
691{
692 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
693 return CPUFREQ_POLICY_PERFORMANCE;
694
695 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
696 return CPUFREQ_POLICY_POWERSAVE;
697
698 return CPUFREQ_POLICY_UNKNOWN;
699}
700
701/**
702 * cpufreq_parse_governor - parse a governor string only for has_target()
703 * @str_governor: Governor name.
704 */
705static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
706{
707 struct cpufreq_governor *t;
708
709 t = get_governor(str_governor);
710 if (t)
711 return t;
712
713 if (request_module("cpufreq_%s", str_governor))
714 return NULL;
715
716 return get_governor(str_governor);
717}
718
719/*
720 * cpufreq_per_cpu_attr_read() / show_##file_name() -
721 * print out cpufreq information
722 *
723 * Write out information from cpufreq_driver->policy[cpu]; object must be
724 * "unsigned int".
725 */
726
727#define show_one(file_name, object) \
728static ssize_t show_##file_name \
729(struct cpufreq_policy *policy, char *buf) \
730{ \
731 return sprintf(buf, "%u\n", policy->object); \
732}
733
734show_one(cpuinfo_min_freq, cpuinfo.min_freq);
735show_one(cpuinfo_max_freq, cpuinfo.max_freq);
736show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
737show_one(scaling_min_freq, min);
738show_one(scaling_max_freq, max);
739
740__weak unsigned int arch_freq_get_on_cpu(int cpu)
741{
742 return 0;
743}
744
745static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
746{
747 ssize_t ret;
748 unsigned int freq;
749
750 freq = arch_freq_get_on_cpu(policy->cpu);
751 if (freq)
752 ret = sprintf(buf, "%u\n", freq);
753 else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
754 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
755 else
756 ret = sprintf(buf, "%u\n", policy->cur);
757 return ret;
758}
759
760/*
761 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
762 */
763#define store_one(file_name, object) \
764static ssize_t store_##file_name \
765(struct cpufreq_policy *policy, const char *buf, size_t count) \
766{ \
767 unsigned long val; \
768 int ret; \
769 \
770 ret = kstrtoul(buf, 0, &val); \
771 if (ret) \
772 return ret; \
773 \
774 ret = freq_qos_update_request(policy->object##_freq_req, val);\
775 return ret >= 0 ? count : ret; \
776}
777
778store_one(scaling_min_freq, min);
779store_one(scaling_max_freq, max);
780
781/*
782 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
783 */
784static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
785 char *buf)
786{
787 unsigned int cur_freq = __cpufreq_get(policy);
788
789 if (cur_freq)
790 return sprintf(buf, "%u\n", cur_freq);
791
792 return sprintf(buf, "<unknown>\n");
793}
794
795/*
796 * show_scaling_governor - show the current policy for the specified CPU
797 */
798static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
799{
800 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
801 return sprintf(buf, "powersave\n");
802 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
803 return sprintf(buf, "performance\n");
804 else if (policy->governor)
805 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
806 policy->governor->name);
807 return -EINVAL;
808}
809
810/*
811 * store_scaling_governor - store policy for the specified CPU
812 */
813static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
814 const char *buf, size_t count)
815{
816 char str_governor[16];
817 int ret;
818
819 ret = sscanf(buf, "%15s", str_governor);
820 if (ret != 1)
821 return -EINVAL;
822
823 if (cpufreq_driver->setpolicy) {
824 unsigned int new_pol;
825
826 new_pol = cpufreq_parse_policy(str_governor);
827 if (!new_pol)
828 return -EINVAL;
829
830 ret = cpufreq_set_policy(policy, NULL, new_pol);
831 } else {
832 struct cpufreq_governor *new_gov;
833
834 new_gov = cpufreq_parse_governor(str_governor);
835 if (!new_gov)
836 return -EINVAL;
837
838 ret = cpufreq_set_policy(policy, new_gov,
839 CPUFREQ_POLICY_UNKNOWN);
840
841 module_put(new_gov->owner);
842 }
843
844 return ret ? ret : count;
845}
846
847/*
848 * show_scaling_driver - show the cpufreq driver currently loaded
849 */
850static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
851{
852 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
853}
854
855/*
856 * show_scaling_available_governors - show the available CPUfreq governors
857 */
858static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
859 char *buf)
860{
861 ssize_t i = 0;
862 struct cpufreq_governor *t;
863
864 if (!has_target()) {
865 i += sprintf(buf, "performance powersave");
866 goto out;
867 }
868
869 mutex_lock(&cpufreq_governor_mutex);
870 for_each_governor(t) {
871 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
872 - (CPUFREQ_NAME_LEN + 2)))
873 break;
874 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
875 }
876 mutex_unlock(&cpufreq_governor_mutex);
877out:
878 i += sprintf(&buf[i], "\n");
879 return i;
880}
881
882ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
883{
884 ssize_t i = 0;
885 unsigned int cpu;
886
887 for_each_cpu(cpu, mask) {
888 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u ", cpu);
889 if (i >= (PAGE_SIZE - 5))
890 break;
891 }
892
893 /* Remove the extra space at the end */
894 i--;
895
896 i += sprintf(&buf[i], "\n");
897 return i;
898}
899EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
900
901/*
902 * show_related_cpus - show the CPUs affected by each transition even if
903 * hw coordination is in use
904 */
905static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
906{
907 return cpufreq_show_cpus(policy->related_cpus, buf);
908}
909
910/*
911 * show_affected_cpus - show the CPUs affected by each transition
912 */
913static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
914{
915 return cpufreq_show_cpus(policy->cpus, buf);
916}
917
918static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
919 const char *buf, size_t count)
920{
921 unsigned int freq = 0;
922 unsigned int ret;
923
924 if (!policy->governor || !policy->governor->store_setspeed)
925 return -EINVAL;
926
927 ret = sscanf(buf, "%u", &freq);
928 if (ret != 1)
929 return -EINVAL;
930
931 policy->governor->store_setspeed(policy, freq);
932
933 return count;
934}
935
936static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
937{
938 if (!policy->governor || !policy->governor->show_setspeed)
939 return sprintf(buf, "<unsupported>\n");
940
941 return policy->governor->show_setspeed(policy, buf);
942}
943
944/*
945 * show_bios_limit - show the current cpufreq HW/BIOS limitation
946 */
947static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
948{
949 unsigned int limit;
950 int ret;
951 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
952 if (!ret)
953 return sprintf(buf, "%u\n", limit);
954 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
955}
956
957cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
958cpufreq_freq_attr_ro(cpuinfo_min_freq);
959cpufreq_freq_attr_ro(cpuinfo_max_freq);
960cpufreq_freq_attr_ro(cpuinfo_transition_latency);
961cpufreq_freq_attr_ro(scaling_available_governors);
962cpufreq_freq_attr_ro(scaling_driver);
963cpufreq_freq_attr_ro(scaling_cur_freq);
964cpufreq_freq_attr_ro(bios_limit);
965cpufreq_freq_attr_ro(related_cpus);
966cpufreq_freq_attr_ro(affected_cpus);
967cpufreq_freq_attr_rw(scaling_min_freq);
968cpufreq_freq_attr_rw(scaling_max_freq);
969cpufreq_freq_attr_rw(scaling_governor);
970cpufreq_freq_attr_rw(scaling_setspeed);
971
972static struct attribute *cpufreq_attrs[] = {
973 &cpuinfo_min_freq.attr,
974 &cpuinfo_max_freq.attr,
975 &cpuinfo_transition_latency.attr,
976 &scaling_min_freq.attr,
977 &scaling_max_freq.attr,
978 &affected_cpus.attr,
979 &related_cpus.attr,
980 &scaling_governor.attr,
981 &scaling_driver.attr,
982 &scaling_available_governors.attr,
983 &scaling_setspeed.attr,
984 NULL
985};
986ATTRIBUTE_GROUPS(cpufreq);
987
988#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
989#define to_attr(a) container_of(a, struct freq_attr, attr)
990
991static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
992{
993 struct cpufreq_policy *policy = to_policy(kobj);
994 struct freq_attr *fattr = to_attr(attr);
995 ssize_t ret = -EBUSY;
996
997 if (!fattr->show)
998 return -EIO;
999
1000 down_read(&policy->rwsem);
1001 if (likely(!policy_is_inactive(policy)))
1002 ret = fattr->show(policy, buf);
1003 up_read(&policy->rwsem);
1004
1005 return ret;
1006}
1007
1008static ssize_t store(struct kobject *kobj, struct attribute *attr,
1009 const char *buf, size_t count)
1010{
1011 struct cpufreq_policy *policy = to_policy(kobj);
1012 struct freq_attr *fattr = to_attr(attr);
1013 ssize_t ret = -EBUSY;
1014
1015 if (!fattr->store)
1016 return -EIO;
1017
1018 down_write(&policy->rwsem);
1019 if (likely(!policy_is_inactive(policy)))
1020 ret = fattr->store(policy, buf, count);
1021 up_write(&policy->rwsem);
1022
1023 return ret;
1024}
1025
1026static void cpufreq_sysfs_release(struct kobject *kobj)
1027{
1028 struct cpufreq_policy *policy = to_policy(kobj);
1029 pr_debug("last reference is dropped\n");
1030 complete(&policy->kobj_unregister);
1031}
1032
1033static const struct sysfs_ops sysfs_ops = {
1034 .show = show,
1035 .store = store,
1036};
1037
1038static const struct kobj_type ktype_cpufreq = {
1039 .sysfs_ops = &sysfs_ops,
1040 .default_groups = cpufreq_groups,
1041 .release = cpufreq_sysfs_release,
1042};
1043
1044static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
1045 struct device *dev)
1046{
1047 if (unlikely(!dev))
1048 return;
1049
1050 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1051 return;
1052
1053 dev_dbg(dev, "%s: Adding symlink\n", __func__);
1054 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1055 dev_err(dev, "cpufreq symlink creation failed\n");
1056}
1057
1058static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu,
1059 struct device *dev)
1060{
1061 dev_dbg(dev, "%s: Removing symlink\n", __func__);
1062 sysfs_remove_link(&dev->kobj, "cpufreq");
1063 cpumask_clear_cpu(cpu, policy->real_cpus);
1064}
1065
1066static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1067{
1068 struct freq_attr **drv_attr;
1069 int ret = 0;
1070
1071 /* set up files for this cpu device */
1072 drv_attr = cpufreq_driver->attr;
1073 while (drv_attr && *drv_attr) {
1074 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1075 if (ret)
1076 return ret;
1077 drv_attr++;
1078 }
1079 if (cpufreq_driver->get) {
1080 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1081 if (ret)
1082 return ret;
1083 }
1084
1085 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1086 if (ret)
1087 return ret;
1088
1089 if (cpufreq_driver->bios_limit) {
1090 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1091 if (ret)
1092 return ret;
1093 }
1094
1095 if (cpufreq_boost_supported()) {
1096 ret = sysfs_create_file(&policy->kobj, &local_boost.attr);
1097 if (ret)
1098 return ret;
1099 }
1100
1101 return 0;
1102}
1103
1104static int cpufreq_init_policy(struct cpufreq_policy *policy)
1105{
1106 struct cpufreq_governor *gov = NULL;
1107 unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
1108 int ret;
1109
1110 if (has_target()) {
1111 /* Update policy governor to the one used before hotplug. */
1112 gov = get_governor(policy->last_governor);
1113 if (gov) {
1114 pr_debug("Restoring governor %s for cpu %d\n",
1115 gov->name, policy->cpu);
1116 } else {
1117 gov = get_governor(default_governor);
1118 }
1119
1120 if (!gov) {
1121 gov = cpufreq_default_governor();
1122 __module_get(gov->owner);
1123 }
1124
1125 } else {
1126
1127 /* Use the default policy if there is no last_policy. */
1128 if (policy->last_policy) {
1129 pol = policy->last_policy;
1130 } else {
1131 pol = cpufreq_parse_policy(default_governor);
1132 /*
1133 * In case the default governor is neither "performance"
1134 * nor "powersave", fall back to the initial policy
1135 * value set by the driver.
1136 */
1137 if (pol == CPUFREQ_POLICY_UNKNOWN)
1138 pol = policy->policy;
1139 }
1140 if (pol != CPUFREQ_POLICY_PERFORMANCE &&
1141 pol != CPUFREQ_POLICY_POWERSAVE)
1142 return -ENODATA;
1143 }
1144
1145 ret = cpufreq_set_policy(policy, gov, pol);
1146 if (gov)
1147 module_put(gov->owner);
1148
1149 return ret;
1150}
1151
1152static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1153{
1154 int ret = 0;
1155
1156 /* Has this CPU been taken care of already? */
1157 if (cpumask_test_cpu(cpu, policy->cpus))
1158 return 0;
1159
1160 down_write(&policy->rwsem);
1161 if (has_target())
1162 cpufreq_stop_governor(policy);
1163
1164 cpumask_set_cpu(cpu, policy->cpus);
1165
1166 if (has_target()) {
1167 ret = cpufreq_start_governor(policy);
1168 if (ret)
1169 pr_err("%s: Failed to start governor\n", __func__);
1170 }
1171 up_write(&policy->rwsem);
1172 return ret;
1173}
1174
1175void refresh_frequency_limits(struct cpufreq_policy *policy)
1176{
1177 if (!policy_is_inactive(policy)) {
1178 pr_debug("updating policy for CPU %u\n", policy->cpu);
1179
1180 cpufreq_set_policy(policy, policy->governor, policy->policy);
1181 }
1182}
1183EXPORT_SYMBOL(refresh_frequency_limits);
1184
1185static void handle_update(struct work_struct *work)
1186{
1187 struct cpufreq_policy *policy =
1188 container_of(work, struct cpufreq_policy, update);
1189
1190 pr_debug("handle_update for cpu %u called\n", policy->cpu);
1191 down_write(&policy->rwsem);
1192 refresh_frequency_limits(policy);
1193 up_write(&policy->rwsem);
1194}
1195
1196static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1197 void *data)
1198{
1199 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1200
1201 schedule_work(&policy->update);
1202 return 0;
1203}
1204
1205static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1206 void *data)
1207{
1208 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1209
1210 schedule_work(&policy->update);
1211 return 0;
1212}
1213
1214static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1215{
1216 struct kobject *kobj;
1217 struct completion *cmp;
1218
1219 down_write(&policy->rwsem);
1220 cpufreq_stats_free_table(policy);
1221 kobj = &policy->kobj;
1222 cmp = &policy->kobj_unregister;
1223 up_write(&policy->rwsem);
1224 kobject_put(kobj);
1225
1226 /*
1227 * We need to make sure that the underlying kobj is
1228 * actually not referenced anymore by anybody before we
1229 * proceed with unloading.
1230 */
1231 pr_debug("waiting for dropping of refcount\n");
1232 wait_for_completion(cmp);
1233 pr_debug("wait complete\n");
1234}
1235
1236static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1237{
1238 struct cpufreq_policy *policy;
1239 struct device *dev = get_cpu_device(cpu);
1240 int ret;
1241
1242 if (!dev)
1243 return NULL;
1244
1245 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1246 if (!policy)
1247 return NULL;
1248
1249 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1250 goto err_free_policy;
1251
1252 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1253 goto err_free_cpumask;
1254
1255 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1256 goto err_free_rcpumask;
1257
1258 init_completion(&policy->kobj_unregister);
1259 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1260 cpufreq_global_kobject, "policy%u", cpu);
1261 if (ret) {
1262 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1263 /*
1264 * The entire policy object will be freed below, but the extra
1265 * memory allocated for the kobject name needs to be freed by
1266 * releasing the kobject.
1267 */
1268 kobject_put(&policy->kobj);
1269 goto err_free_real_cpus;
1270 }
1271
1272 freq_constraints_init(&policy->constraints);
1273
1274 policy->nb_min.notifier_call = cpufreq_notifier_min;
1275 policy->nb_max.notifier_call = cpufreq_notifier_max;
1276
1277 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1278 &policy->nb_min);
1279 if (ret) {
1280 dev_err(dev, "Failed to register MIN QoS notifier: %d (CPU%u)\n",
1281 ret, cpu);
1282 goto err_kobj_remove;
1283 }
1284
1285 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1286 &policy->nb_max);
1287 if (ret) {
1288 dev_err(dev, "Failed to register MAX QoS notifier: %d (CPU%u)\n",
1289 ret, cpu);
1290 goto err_min_qos_notifier;
1291 }
1292
1293 INIT_LIST_HEAD(&policy->policy_list);
1294 init_rwsem(&policy->rwsem);
1295 spin_lock_init(&policy->transition_lock);
1296 init_waitqueue_head(&policy->transition_wait);
1297 INIT_WORK(&policy->update, handle_update);
1298
1299 policy->cpu = cpu;
1300 return policy;
1301
1302err_min_qos_notifier:
1303 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1304 &policy->nb_min);
1305err_kobj_remove:
1306 cpufreq_policy_put_kobj(policy);
1307err_free_real_cpus:
1308 free_cpumask_var(policy->real_cpus);
1309err_free_rcpumask:
1310 free_cpumask_var(policy->related_cpus);
1311err_free_cpumask:
1312 free_cpumask_var(policy->cpus);
1313err_free_policy:
1314 kfree(policy);
1315
1316 return NULL;
1317}
1318
1319static void cpufreq_policy_free(struct cpufreq_policy *policy)
1320{
1321 unsigned long flags;
1322 int cpu;
1323
1324 /*
1325 * The callers must ensure the policy is inactive by now, to avoid any
1326 * races with show()/store() callbacks.
1327 */
1328 if (unlikely(!policy_is_inactive(policy)))
1329 pr_warn("%s: Freeing active policy\n", __func__);
1330
1331 /* Remove policy from list */
1332 write_lock_irqsave(&cpufreq_driver_lock, flags);
1333 list_del(&policy->policy_list);
1334
1335 for_each_cpu(cpu, policy->related_cpus)
1336 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1337 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1338
1339 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1340 &policy->nb_max);
1341 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1342 &policy->nb_min);
1343
1344 /* Cancel any pending policy->update work before freeing the policy. */
1345 cancel_work_sync(&policy->update);
1346
1347 if (policy->max_freq_req) {
1348 /*
1349 * Remove max_freq_req after sending CPUFREQ_REMOVE_POLICY
1350 * notification, since CPUFREQ_CREATE_POLICY notification was
1351 * sent after adding max_freq_req earlier.
1352 */
1353 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1354 CPUFREQ_REMOVE_POLICY, policy);
1355 freq_qos_remove_request(policy->max_freq_req);
1356 }
1357
1358 freq_qos_remove_request(policy->min_freq_req);
1359 kfree(policy->min_freq_req);
1360
1361 cpufreq_policy_put_kobj(policy);
1362 free_cpumask_var(policy->real_cpus);
1363 free_cpumask_var(policy->related_cpus);
1364 free_cpumask_var(policy->cpus);
1365 kfree(policy);
1366}
1367
1368static int cpufreq_online(unsigned int cpu)
1369{
1370 struct cpufreq_policy *policy;
1371 bool new_policy;
1372 unsigned long flags;
1373 unsigned int j;
1374 int ret;
1375
1376 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1377
1378 /* Check if this CPU already has a policy to manage it */
1379 policy = per_cpu(cpufreq_cpu_data, cpu);
1380 if (policy) {
1381 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1382 if (!policy_is_inactive(policy))
1383 return cpufreq_add_policy_cpu(policy, cpu);
1384
1385 /* This is the only online CPU for the policy. Start over. */
1386 new_policy = false;
1387 down_write(&policy->rwsem);
1388 policy->cpu = cpu;
1389 policy->governor = NULL;
1390 } else {
1391 new_policy = true;
1392 policy = cpufreq_policy_alloc(cpu);
1393 if (!policy)
1394 return -ENOMEM;
1395 down_write(&policy->rwsem);
1396 }
1397
1398 if (!new_policy && cpufreq_driver->online) {
1399 /* Recover policy->cpus using related_cpus */
1400 cpumask_copy(policy->cpus, policy->related_cpus);
1401
1402 ret = cpufreq_driver->online(policy);
1403 if (ret) {
1404 pr_debug("%s: %d: initialization failed\n", __func__,
1405 __LINE__);
1406 goto out_exit_policy;
1407 }
1408 } else {
1409 cpumask_copy(policy->cpus, cpumask_of(cpu));
1410
1411 /*
1412 * Call driver. From then on the cpufreq must be able
1413 * to accept all calls to ->verify and ->setpolicy for this CPU.
1414 */
1415 ret = cpufreq_driver->init(policy);
1416 if (ret) {
1417 pr_debug("%s: %d: initialization failed\n", __func__,
1418 __LINE__);
1419 goto out_free_policy;
1420 }
1421
1422 /*
1423 * The initialization has succeeded and the policy is online.
1424 * If there is a problem with its frequency table, take it
1425 * offline and drop it.
1426 */
1427 ret = cpufreq_table_validate_and_sort(policy);
1428 if (ret)
1429 goto out_offline_policy;
1430
1431 /* related_cpus should at least include policy->cpus. */
1432 cpumask_copy(policy->related_cpus, policy->cpus);
1433 }
1434
1435 /*
1436 * affected cpus must always be the one, which are online. We aren't
1437 * managing offline cpus here.
1438 */
1439 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1440
1441 if (new_policy) {
1442 for_each_cpu(j, policy->related_cpus) {
1443 per_cpu(cpufreq_cpu_data, j) = policy;
1444 add_cpu_dev_symlink(policy, j, get_cpu_device(j));
1445 }
1446
1447 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1448 GFP_KERNEL);
1449 if (!policy->min_freq_req) {
1450 ret = -ENOMEM;
1451 goto out_destroy_policy;
1452 }
1453
1454 ret = freq_qos_add_request(&policy->constraints,
1455 policy->min_freq_req, FREQ_QOS_MIN,
1456 FREQ_QOS_MIN_DEFAULT_VALUE);
1457 if (ret < 0) {
1458 /*
1459 * So we don't call freq_qos_remove_request() for an
1460 * uninitialized request.
1461 */
1462 kfree(policy->min_freq_req);
1463 policy->min_freq_req = NULL;
1464 goto out_destroy_policy;
1465 }
1466
1467 /*
1468 * This must be initialized right here to avoid calling
1469 * freq_qos_remove_request() on uninitialized request in case
1470 * of errors.
1471 */
1472 policy->max_freq_req = policy->min_freq_req + 1;
1473
1474 ret = freq_qos_add_request(&policy->constraints,
1475 policy->max_freq_req, FREQ_QOS_MAX,
1476 FREQ_QOS_MAX_DEFAULT_VALUE);
1477 if (ret < 0) {
1478 policy->max_freq_req = NULL;
1479 goto out_destroy_policy;
1480 }
1481
1482 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1483 CPUFREQ_CREATE_POLICY, policy);
1484 }
1485
1486 if (cpufreq_driver->get && has_target()) {
1487 policy->cur = cpufreq_driver->get(policy->cpu);
1488 if (!policy->cur) {
1489 ret = -EIO;
1490 pr_err("%s: ->get() failed\n", __func__);
1491 goto out_destroy_policy;
1492 }
1493 }
1494
1495 /*
1496 * Sometimes boot loaders set CPU frequency to a value outside of
1497 * frequency table present with cpufreq core. In such cases CPU might be
1498 * unstable if it has to run on that frequency for long duration of time
1499 * and so its better to set it to a frequency which is specified in
1500 * freq-table. This also makes cpufreq stats inconsistent as
1501 * cpufreq-stats would fail to register because current frequency of CPU
1502 * isn't found in freq-table.
1503 *
1504 * Because we don't want this change to effect boot process badly, we go
1505 * for the next freq which is >= policy->cur ('cur' must be set by now,
1506 * otherwise we will end up setting freq to lowest of the table as 'cur'
1507 * is initialized to zero).
1508 *
1509 * We are passing target-freq as "policy->cur - 1" otherwise
1510 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1511 * equal to target-freq.
1512 */
1513 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1514 && has_target()) {
1515 unsigned int old_freq = policy->cur;
1516
1517 /* Are we running at unknown frequency ? */
1518 ret = cpufreq_frequency_table_get_index(policy, old_freq);
1519 if (ret == -EINVAL) {
1520 ret = __cpufreq_driver_target(policy, old_freq - 1,
1521 CPUFREQ_RELATION_L);
1522
1523 /*
1524 * Reaching here after boot in a few seconds may not
1525 * mean that system will remain stable at "unknown"
1526 * frequency for longer duration. Hence, a BUG_ON().
1527 */
1528 BUG_ON(ret);
1529 pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
1530 __func__, policy->cpu, old_freq, policy->cur);
1531 }
1532 }
1533
1534 if (new_policy) {
1535 ret = cpufreq_add_dev_interface(policy);
1536 if (ret)
1537 goto out_destroy_policy;
1538
1539 cpufreq_stats_create_table(policy);
1540
1541 write_lock_irqsave(&cpufreq_driver_lock, flags);
1542 list_add(&policy->policy_list, &cpufreq_policy_list);
1543 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1544
1545 /*
1546 * Register with the energy model before
1547 * sugov_eas_rebuild_sd() is called, which will result
1548 * in rebuilding of the sched domains, which should only be done
1549 * once the energy model is properly initialized for the policy
1550 * first.
1551 *
1552 * Also, this should be called before the policy is registered
1553 * with cooling framework.
1554 */
1555 if (cpufreq_driver->register_em)
1556 cpufreq_driver->register_em(policy);
1557 }
1558
1559 ret = cpufreq_init_policy(policy);
1560 if (ret) {
1561 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1562 __func__, cpu, ret);
1563 goto out_destroy_policy;
1564 }
1565
1566 up_write(&policy->rwsem);
1567
1568 kobject_uevent(&policy->kobj, KOBJ_ADD);
1569
1570 /* Callback for handling stuff after policy is ready */
1571 if (cpufreq_driver->ready)
1572 cpufreq_driver->ready(policy);
1573
1574 if (cpufreq_thermal_control_enabled(cpufreq_driver))
1575 policy->cdev = of_cpufreq_cooling_register(policy);
1576
1577 pr_debug("initialization complete\n");
1578
1579 return 0;
1580
1581out_destroy_policy:
1582 for_each_cpu(j, policy->real_cpus)
1583 remove_cpu_dev_symlink(policy, j, get_cpu_device(j));
1584
1585out_offline_policy:
1586 if (cpufreq_driver->offline)
1587 cpufreq_driver->offline(policy);
1588
1589out_exit_policy:
1590 if (cpufreq_driver->exit)
1591 cpufreq_driver->exit(policy);
1592
1593out_free_policy:
1594 cpumask_clear(policy->cpus);
1595 up_write(&policy->rwsem);
1596
1597 cpufreq_policy_free(policy);
1598 return ret;
1599}
1600
1601/**
1602 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1603 * @dev: CPU device.
1604 * @sif: Subsystem interface structure pointer (not used)
1605 */
1606static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1607{
1608 struct cpufreq_policy *policy;
1609 unsigned cpu = dev->id;
1610 int ret;
1611
1612 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1613
1614 if (cpu_online(cpu)) {
1615 ret = cpufreq_online(cpu);
1616 if (ret)
1617 return ret;
1618 }
1619
1620 /* Create sysfs link on CPU registration */
1621 policy = per_cpu(cpufreq_cpu_data, cpu);
1622 if (policy)
1623 add_cpu_dev_symlink(policy, cpu, dev);
1624
1625 return 0;
1626}
1627
1628static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy)
1629{
1630 int ret;
1631
1632 if (has_target())
1633 cpufreq_stop_governor(policy);
1634
1635 cpumask_clear_cpu(cpu, policy->cpus);
1636
1637 if (!policy_is_inactive(policy)) {
1638 /* Nominate a new CPU if necessary. */
1639 if (cpu == policy->cpu)
1640 policy->cpu = cpumask_any(policy->cpus);
1641
1642 /* Start the governor again for the active policy. */
1643 if (has_target()) {
1644 ret = cpufreq_start_governor(policy);
1645 if (ret)
1646 pr_err("%s: Failed to start governor\n", __func__);
1647 }
1648
1649 return;
1650 }
1651
1652 if (has_target())
1653 strscpy(policy->last_governor, policy->governor->name,
1654 CPUFREQ_NAME_LEN);
1655 else
1656 policy->last_policy = policy->policy;
1657
1658 if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1659 cpufreq_cooling_unregister(policy->cdev);
1660 policy->cdev = NULL;
1661 }
1662
1663 if (has_target())
1664 cpufreq_exit_governor(policy);
1665
1666 /*
1667 * Perform the ->offline() during light-weight tear-down, as
1668 * that allows fast recovery when the CPU comes back.
1669 */
1670 if (cpufreq_driver->offline) {
1671 cpufreq_driver->offline(policy);
1672 } else if (cpufreq_driver->exit) {
1673 cpufreq_driver->exit(policy);
1674 policy->freq_table = NULL;
1675 }
1676}
1677
1678static int cpufreq_offline(unsigned int cpu)
1679{
1680 struct cpufreq_policy *policy;
1681
1682 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1683
1684 policy = cpufreq_cpu_get_raw(cpu);
1685 if (!policy) {
1686 pr_debug("%s: No cpu_data found\n", __func__);
1687 return 0;
1688 }
1689
1690 down_write(&policy->rwsem);
1691
1692 __cpufreq_offline(cpu, policy);
1693
1694 up_write(&policy->rwsem);
1695 return 0;
1696}
1697
1698/*
1699 * cpufreq_remove_dev - remove a CPU device
1700 *
1701 * Removes the cpufreq interface for a CPU device.
1702 */
1703static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1704{
1705 unsigned int cpu = dev->id;
1706 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1707
1708 if (!policy)
1709 return;
1710
1711 down_write(&policy->rwsem);
1712
1713 if (cpu_online(cpu))
1714 __cpufreq_offline(cpu, policy);
1715
1716 remove_cpu_dev_symlink(policy, cpu, dev);
1717
1718 if (!cpumask_empty(policy->real_cpus)) {
1719 up_write(&policy->rwsem);
1720 return;
1721 }
1722
1723 /* We did light-weight exit earlier, do full tear down now */
1724 if (cpufreq_driver->offline)
1725 cpufreq_driver->exit(policy);
1726
1727 up_write(&policy->rwsem);
1728
1729 cpufreq_policy_free(policy);
1730}
1731
1732/**
1733 * cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
1734 * @policy: Policy managing CPUs.
1735 * @new_freq: New CPU frequency.
1736 *
1737 * Adjust to the current frequency first and clean up later by either calling
1738 * cpufreq_update_policy(), or scheduling handle_update().
1739 */
1740static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1741 unsigned int new_freq)
1742{
1743 struct cpufreq_freqs freqs;
1744
1745 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1746 policy->cur, new_freq);
1747
1748 freqs.old = policy->cur;
1749 freqs.new = new_freq;
1750
1751 cpufreq_freq_transition_begin(policy, &freqs);
1752 cpufreq_freq_transition_end(policy, &freqs, 0);
1753}
1754
1755static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1756{
1757 unsigned int new_freq;
1758
1759 new_freq = cpufreq_driver->get(policy->cpu);
1760 if (!new_freq)
1761 return 0;
1762
1763 /*
1764 * If fast frequency switching is used with the given policy, the check
1765 * against policy->cur is pointless, so skip it in that case.
1766 */
1767 if (policy->fast_switch_enabled || !has_target())
1768 return new_freq;
1769
1770 if (policy->cur != new_freq) {
1771 /*
1772 * For some platforms, the frequency returned by hardware may be
1773 * slightly different from what is provided in the frequency
1774 * table, for example hardware may return 499 MHz instead of 500
1775 * MHz. In such cases it is better to avoid getting into
1776 * unnecessary frequency updates.
1777 */
1778 if (abs(policy->cur - new_freq) < KHZ_PER_MHZ)
1779 return policy->cur;
1780
1781 cpufreq_out_of_sync(policy, new_freq);
1782 if (update)
1783 schedule_work(&policy->update);
1784 }
1785
1786 return new_freq;
1787}
1788
1789/**
1790 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1791 * @cpu: CPU number
1792 *
1793 * This is the last known freq, without actually getting it from the driver.
1794 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1795 */
1796unsigned int cpufreq_quick_get(unsigned int cpu)
1797{
1798 struct cpufreq_policy *policy;
1799 unsigned int ret_freq = 0;
1800 unsigned long flags;
1801
1802 read_lock_irqsave(&cpufreq_driver_lock, flags);
1803
1804 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1805 ret_freq = cpufreq_driver->get(cpu);
1806 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1807 return ret_freq;
1808 }
1809
1810 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1811
1812 policy = cpufreq_cpu_get(cpu);
1813 if (policy) {
1814 ret_freq = policy->cur;
1815 cpufreq_cpu_put(policy);
1816 }
1817
1818 return ret_freq;
1819}
1820EXPORT_SYMBOL(cpufreq_quick_get);
1821
1822/**
1823 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1824 * @cpu: CPU number
1825 *
1826 * Just return the max possible frequency for a given CPU.
1827 */
1828unsigned int cpufreq_quick_get_max(unsigned int cpu)
1829{
1830 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1831 unsigned int ret_freq = 0;
1832
1833 if (policy) {
1834 ret_freq = policy->max;
1835 cpufreq_cpu_put(policy);
1836 }
1837
1838 return ret_freq;
1839}
1840EXPORT_SYMBOL(cpufreq_quick_get_max);
1841
1842/**
1843 * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
1844 * @cpu: CPU number
1845 *
1846 * The default return value is the max_freq field of cpuinfo.
1847 */
1848__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
1849{
1850 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1851 unsigned int ret_freq = 0;
1852
1853 if (policy) {
1854 ret_freq = policy->cpuinfo.max_freq;
1855 cpufreq_cpu_put(policy);
1856 }
1857
1858 return ret_freq;
1859}
1860EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
1861
1862static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1863{
1864 if (unlikely(policy_is_inactive(policy)))
1865 return 0;
1866
1867 return cpufreq_verify_current_freq(policy, true);
1868}
1869
1870/**
1871 * cpufreq_get - get the current CPU frequency (in kHz)
1872 * @cpu: CPU number
1873 *
1874 * Get the CPU current (static) CPU frequency
1875 */
1876unsigned int cpufreq_get(unsigned int cpu)
1877{
1878 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1879 unsigned int ret_freq = 0;
1880
1881 if (policy) {
1882 down_read(&policy->rwsem);
1883 if (cpufreq_driver->get)
1884 ret_freq = __cpufreq_get(policy);
1885 up_read(&policy->rwsem);
1886
1887 cpufreq_cpu_put(policy);
1888 }
1889
1890 return ret_freq;
1891}
1892EXPORT_SYMBOL(cpufreq_get);
1893
1894static struct subsys_interface cpufreq_interface = {
1895 .name = "cpufreq",
1896 .subsys = &cpu_subsys,
1897 .add_dev = cpufreq_add_dev,
1898 .remove_dev = cpufreq_remove_dev,
1899};
1900
1901/*
1902 * In case platform wants some specific frequency to be configured
1903 * during suspend..
1904 */
1905int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1906{
1907 int ret;
1908
1909 if (!policy->suspend_freq) {
1910 pr_debug("%s: suspend_freq not defined\n", __func__);
1911 return 0;
1912 }
1913
1914 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1915 policy->suspend_freq);
1916
1917 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1918 CPUFREQ_RELATION_H);
1919 if (ret)
1920 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1921 __func__, policy->suspend_freq, ret);
1922
1923 return ret;
1924}
1925EXPORT_SYMBOL(cpufreq_generic_suspend);
1926
1927/**
1928 * cpufreq_suspend() - Suspend CPUFreq governors.
1929 *
1930 * Called during system wide Suspend/Hibernate cycles for suspending governors
1931 * as some platforms can't change frequency after this point in suspend cycle.
1932 * Because some of the devices (like: i2c, regulators, etc) they use for
1933 * changing frequency are suspended quickly after this point.
1934 */
1935void cpufreq_suspend(void)
1936{
1937 struct cpufreq_policy *policy;
1938
1939 if (!cpufreq_driver)
1940 return;
1941
1942 if (!has_target() && !cpufreq_driver->suspend)
1943 goto suspend;
1944
1945 pr_debug("%s: Suspending Governors\n", __func__);
1946
1947 for_each_active_policy(policy) {
1948 if (has_target()) {
1949 down_write(&policy->rwsem);
1950 cpufreq_stop_governor(policy);
1951 up_write(&policy->rwsem);
1952 }
1953
1954 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1955 pr_err("%s: Failed to suspend driver: %s\n", __func__,
1956 cpufreq_driver->name);
1957 }
1958
1959suspend:
1960 cpufreq_suspended = true;
1961}
1962
1963/**
1964 * cpufreq_resume() - Resume CPUFreq governors.
1965 *
1966 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1967 * are suspended with cpufreq_suspend().
1968 */
1969void cpufreq_resume(void)
1970{
1971 struct cpufreq_policy *policy;
1972 int ret;
1973
1974 if (!cpufreq_driver)
1975 return;
1976
1977 if (unlikely(!cpufreq_suspended))
1978 return;
1979
1980 cpufreq_suspended = false;
1981
1982 if (!has_target() && !cpufreq_driver->resume)
1983 return;
1984
1985 pr_debug("%s: Resuming Governors\n", __func__);
1986
1987 for_each_active_policy(policy) {
1988 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1989 pr_err("%s: Failed to resume driver: %s\n", __func__,
1990 cpufreq_driver->name);
1991 } else if (has_target()) {
1992 down_write(&policy->rwsem);
1993 ret = cpufreq_start_governor(policy);
1994 up_write(&policy->rwsem);
1995
1996 if (ret)
1997 pr_err("%s: Failed to start governor for CPU%u's policy\n",
1998 __func__, policy->cpu);
1999 }
2000 }
2001}
2002
2003/**
2004 * cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
2005 * @flags: Flags to test against the current cpufreq driver's flags.
2006 *
2007 * Assumes that the driver is there, so callers must ensure that this is the
2008 * case.
2009 */
2010bool cpufreq_driver_test_flags(u16 flags)
2011{
2012 return !!(cpufreq_driver->flags & flags);
2013}
2014
2015/**
2016 * cpufreq_get_current_driver - Return the current driver's name.
2017 *
2018 * Return the name string of the currently registered cpufreq driver or NULL if
2019 * none.
2020 */
2021const char *cpufreq_get_current_driver(void)
2022{
2023 if (cpufreq_driver)
2024 return cpufreq_driver->name;
2025
2026 return NULL;
2027}
2028EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
2029
2030/**
2031 * cpufreq_get_driver_data - Return current driver data.
2032 *
2033 * Return the private data of the currently registered cpufreq driver, or NULL
2034 * if no cpufreq driver has been registered.
2035 */
2036void *cpufreq_get_driver_data(void)
2037{
2038 if (cpufreq_driver)
2039 return cpufreq_driver->driver_data;
2040
2041 return NULL;
2042}
2043EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
2044
2045/*********************************************************************
2046 * NOTIFIER LISTS INTERFACE *
2047 *********************************************************************/
2048
2049/**
2050 * cpufreq_register_notifier - Register a notifier with cpufreq.
2051 * @nb: notifier function to register.
2052 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2053 *
2054 * Add a notifier to one of two lists: either a list of notifiers that run on
2055 * clock rate changes (once before and once after every transition), or a list
2056 * of notifiers that ron on cpufreq policy changes.
2057 *
2058 * This function may sleep and it has the same return values as
2059 * blocking_notifier_chain_register().
2060 */
2061int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
2062{
2063 int ret;
2064
2065 if (cpufreq_disabled())
2066 return -EINVAL;
2067
2068 switch (list) {
2069 case CPUFREQ_TRANSITION_NOTIFIER:
2070 mutex_lock(&cpufreq_fast_switch_lock);
2071
2072 if (cpufreq_fast_switch_count > 0) {
2073 mutex_unlock(&cpufreq_fast_switch_lock);
2074 return -EBUSY;
2075 }
2076 ret = srcu_notifier_chain_register(
2077 &cpufreq_transition_notifier_list, nb);
2078 if (!ret)
2079 cpufreq_fast_switch_count--;
2080
2081 mutex_unlock(&cpufreq_fast_switch_lock);
2082 break;
2083 case CPUFREQ_POLICY_NOTIFIER:
2084 ret = blocking_notifier_chain_register(
2085 &cpufreq_policy_notifier_list, nb);
2086 break;
2087 default:
2088 ret = -EINVAL;
2089 }
2090
2091 return ret;
2092}
2093EXPORT_SYMBOL(cpufreq_register_notifier);
2094
2095/**
2096 * cpufreq_unregister_notifier - Unregister a notifier from cpufreq.
2097 * @nb: notifier block to be unregistered.
2098 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2099 *
2100 * Remove a notifier from one of the cpufreq notifier lists.
2101 *
2102 * This function may sleep and it has the same return values as
2103 * blocking_notifier_chain_unregister().
2104 */
2105int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
2106{
2107 int ret;
2108
2109 if (cpufreq_disabled())
2110 return -EINVAL;
2111
2112 switch (list) {
2113 case CPUFREQ_TRANSITION_NOTIFIER:
2114 mutex_lock(&cpufreq_fast_switch_lock);
2115
2116 ret = srcu_notifier_chain_unregister(
2117 &cpufreq_transition_notifier_list, nb);
2118 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
2119 cpufreq_fast_switch_count++;
2120
2121 mutex_unlock(&cpufreq_fast_switch_lock);
2122 break;
2123 case CPUFREQ_POLICY_NOTIFIER:
2124 ret = blocking_notifier_chain_unregister(
2125 &cpufreq_policy_notifier_list, nb);
2126 break;
2127 default:
2128 ret = -EINVAL;
2129 }
2130
2131 return ret;
2132}
2133EXPORT_SYMBOL(cpufreq_unregister_notifier);
2134
2135
2136/*********************************************************************
2137 * GOVERNORS *
2138 *********************************************************************/
2139
2140/**
2141 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
2142 * @policy: cpufreq policy to switch the frequency for.
2143 * @target_freq: New frequency to set (may be approximate).
2144 *
2145 * Carry out a fast frequency switch without sleeping.
2146 *
2147 * The driver's ->fast_switch() callback invoked by this function must be
2148 * suitable for being called from within RCU-sched read-side critical sections
2149 * and it is expected to select the minimum available frequency greater than or
2150 * equal to @target_freq (CPUFREQ_RELATION_L).
2151 *
2152 * This function must not be called if policy->fast_switch_enabled is unset.
2153 *
2154 * Governors calling this function must guarantee that it will never be invoked
2155 * twice in parallel for the same policy and that it will never be called in
2156 * parallel with either ->target() or ->target_index() for the same policy.
2157 *
2158 * Returns the actual frequency set for the CPU.
2159 *
2160 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2161 * error condition, the hardware configuration must be preserved.
2162 */
2163unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2164 unsigned int target_freq)
2165{
2166 unsigned int freq;
2167 int cpu;
2168
2169 target_freq = clamp_val(target_freq, policy->min, policy->max);
2170 freq = cpufreq_driver->fast_switch(policy, target_freq);
2171
2172 if (!freq)
2173 return 0;
2174
2175 policy->cur = freq;
2176 arch_set_freq_scale(policy->related_cpus, freq,
2177 arch_scale_freq_ref(policy->cpu));
2178 cpufreq_stats_record_transition(policy, freq);
2179
2180 if (trace_cpu_frequency_enabled()) {
2181 for_each_cpu(cpu, policy->cpus)
2182 trace_cpu_frequency(freq, cpu);
2183 }
2184
2185 return freq;
2186}
2187EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2188
2189/**
2190 * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
2191 * @cpu: Target CPU.
2192 * @min_perf: Minimum (required) performance level (units of @capacity).
2193 * @target_perf: Target (desired) performance level (units of @capacity).
2194 * @capacity: Capacity of the target CPU.
2195 *
2196 * Carry out a fast performance level switch of @cpu without sleeping.
2197 *
2198 * The driver's ->adjust_perf() callback invoked by this function must be
2199 * suitable for being called from within RCU-sched read-side critical sections
2200 * and it is expected to select a suitable performance level equal to or above
2201 * @min_perf and preferably equal to or below @target_perf.
2202 *
2203 * This function must not be called if policy->fast_switch_enabled is unset.
2204 *
2205 * Governors calling this function must guarantee that it will never be invoked
2206 * twice in parallel for the same CPU and that it will never be called in
2207 * parallel with either ->target() or ->target_index() or ->fast_switch() for
2208 * the same CPU.
2209 */
2210void cpufreq_driver_adjust_perf(unsigned int cpu,
2211 unsigned long min_perf,
2212 unsigned long target_perf,
2213 unsigned long capacity)
2214{
2215 cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
2216}
2217
2218/**
2219 * cpufreq_driver_has_adjust_perf - Check "direct fast switch" callback.
2220 *
2221 * Return 'true' if the ->adjust_perf callback is present for the
2222 * current driver or 'false' otherwise.
2223 */
2224bool cpufreq_driver_has_adjust_perf(void)
2225{
2226 return !!cpufreq_driver->adjust_perf;
2227}
2228
2229/* Must set freqs->new to intermediate frequency */
2230static int __target_intermediate(struct cpufreq_policy *policy,
2231 struct cpufreq_freqs *freqs, int index)
2232{
2233 int ret;
2234
2235 freqs->new = cpufreq_driver->get_intermediate(policy, index);
2236
2237 /* We don't need to switch to intermediate freq */
2238 if (!freqs->new)
2239 return 0;
2240
2241 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2242 __func__, policy->cpu, freqs->old, freqs->new);
2243
2244 cpufreq_freq_transition_begin(policy, freqs);
2245 ret = cpufreq_driver->target_intermediate(policy, index);
2246 cpufreq_freq_transition_end(policy, freqs, ret);
2247
2248 if (ret)
2249 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2250 __func__, ret);
2251
2252 return ret;
2253}
2254
2255static int __target_index(struct cpufreq_policy *policy, int index)
2256{
2257 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2258 unsigned int restore_freq, intermediate_freq = 0;
2259 unsigned int newfreq = policy->freq_table[index].frequency;
2260 int retval = -EINVAL;
2261 bool notify;
2262
2263 if (newfreq == policy->cur)
2264 return 0;
2265
2266 /* Save last value to restore later on errors */
2267 restore_freq = policy->cur;
2268
2269 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2270 if (notify) {
2271 /* Handle switching to intermediate frequency */
2272 if (cpufreq_driver->get_intermediate) {
2273 retval = __target_intermediate(policy, &freqs, index);
2274 if (retval)
2275 return retval;
2276
2277 intermediate_freq = freqs.new;
2278 /* Set old freq to intermediate */
2279 if (intermediate_freq)
2280 freqs.old = freqs.new;
2281 }
2282
2283 freqs.new = newfreq;
2284 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2285 __func__, policy->cpu, freqs.old, freqs.new);
2286
2287 cpufreq_freq_transition_begin(policy, &freqs);
2288 }
2289
2290 retval = cpufreq_driver->target_index(policy, index);
2291 if (retval)
2292 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2293 retval);
2294
2295 if (notify) {
2296 cpufreq_freq_transition_end(policy, &freqs, retval);
2297
2298 /*
2299 * Failed after setting to intermediate freq? Driver should have
2300 * reverted back to initial frequency and so should we. Check
2301 * here for intermediate_freq instead of get_intermediate, in
2302 * case we haven't switched to intermediate freq at all.
2303 */
2304 if (unlikely(retval && intermediate_freq)) {
2305 freqs.old = intermediate_freq;
2306 freqs.new = restore_freq;
2307 cpufreq_freq_transition_begin(policy, &freqs);
2308 cpufreq_freq_transition_end(policy, &freqs, 0);
2309 }
2310 }
2311
2312 return retval;
2313}
2314
2315int __cpufreq_driver_target(struct cpufreq_policy *policy,
2316 unsigned int target_freq,
2317 unsigned int relation)
2318{
2319 unsigned int old_target_freq = target_freq;
2320
2321 if (cpufreq_disabled())
2322 return -ENODEV;
2323
2324 target_freq = __resolve_freq(policy, target_freq, relation);
2325
2326 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2327 policy->cpu, target_freq, relation, old_target_freq);
2328
2329 /*
2330 * This might look like a redundant call as we are checking it again
2331 * after finding index. But it is left intentionally for cases where
2332 * exactly same freq is called again and so we can save on few function
2333 * calls.
2334 */
2335 if (target_freq == policy->cur &&
2336 !(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS))
2337 return 0;
2338
2339 if (cpufreq_driver->target) {
2340 /*
2341 * If the driver hasn't setup a single inefficient frequency,
2342 * it's unlikely it knows how to decode CPUFREQ_RELATION_E.
2343 */
2344 if (!policy->efficiencies_available)
2345 relation &= ~CPUFREQ_RELATION_E;
2346
2347 return cpufreq_driver->target(policy, target_freq, relation);
2348 }
2349
2350 if (!cpufreq_driver->target_index)
2351 return -EINVAL;
2352
2353 return __target_index(policy, policy->cached_resolved_idx);
2354}
2355EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2356
2357int cpufreq_driver_target(struct cpufreq_policy *policy,
2358 unsigned int target_freq,
2359 unsigned int relation)
2360{
2361 int ret;
2362
2363 down_write(&policy->rwsem);
2364
2365 ret = __cpufreq_driver_target(policy, target_freq, relation);
2366
2367 up_write(&policy->rwsem);
2368
2369 return ret;
2370}
2371EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2372
2373__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2374{
2375 return NULL;
2376}
2377
2378static int cpufreq_init_governor(struct cpufreq_policy *policy)
2379{
2380 int ret;
2381
2382 /* Don't start any governor operations if we are entering suspend */
2383 if (cpufreq_suspended)
2384 return 0;
2385 /*
2386 * Governor might not be initiated here if ACPI _PPC changed
2387 * notification happened, so check it.
2388 */
2389 if (!policy->governor)
2390 return -EINVAL;
2391
2392 /* Platform doesn't want dynamic frequency switching ? */
2393 if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING &&
2394 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2395 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2396
2397 if (gov) {
2398 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2399 policy->governor->name, gov->name);
2400 policy->governor = gov;
2401 } else {
2402 return -EINVAL;
2403 }
2404 }
2405
2406 if (!try_module_get(policy->governor->owner))
2407 return -EINVAL;
2408
2409 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2410
2411 if (policy->governor->init) {
2412 ret = policy->governor->init(policy);
2413 if (ret) {
2414 module_put(policy->governor->owner);
2415 return ret;
2416 }
2417 }
2418
2419 policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET);
2420
2421 return 0;
2422}
2423
2424static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2425{
2426 if (cpufreq_suspended || !policy->governor)
2427 return;
2428
2429 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2430
2431 if (policy->governor->exit)
2432 policy->governor->exit(policy);
2433
2434 module_put(policy->governor->owner);
2435}
2436
2437int cpufreq_start_governor(struct cpufreq_policy *policy)
2438{
2439 int ret;
2440
2441 if (cpufreq_suspended)
2442 return 0;
2443
2444 if (!policy->governor)
2445 return -EINVAL;
2446
2447 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2448
2449 if (cpufreq_driver->get)
2450 cpufreq_verify_current_freq(policy, false);
2451
2452 if (policy->governor->start) {
2453 ret = policy->governor->start(policy);
2454 if (ret)
2455 return ret;
2456 }
2457
2458 if (policy->governor->limits)
2459 policy->governor->limits(policy);
2460
2461 return 0;
2462}
2463
2464void cpufreq_stop_governor(struct cpufreq_policy *policy)
2465{
2466 if (cpufreq_suspended || !policy->governor)
2467 return;
2468
2469 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2470
2471 if (policy->governor->stop)
2472 policy->governor->stop(policy);
2473}
2474
2475static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2476{
2477 if (cpufreq_suspended || !policy->governor)
2478 return;
2479
2480 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2481
2482 if (policy->governor->limits)
2483 policy->governor->limits(policy);
2484}
2485
2486int cpufreq_register_governor(struct cpufreq_governor *governor)
2487{
2488 int err;
2489
2490 if (!governor)
2491 return -EINVAL;
2492
2493 if (cpufreq_disabled())
2494 return -ENODEV;
2495
2496 mutex_lock(&cpufreq_governor_mutex);
2497
2498 err = -EBUSY;
2499 if (!find_governor(governor->name)) {
2500 err = 0;
2501 list_add(&governor->governor_list, &cpufreq_governor_list);
2502 }
2503
2504 mutex_unlock(&cpufreq_governor_mutex);
2505 return err;
2506}
2507EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2508
2509void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2510{
2511 struct cpufreq_policy *policy;
2512 unsigned long flags;
2513
2514 if (!governor)
2515 return;
2516
2517 if (cpufreq_disabled())
2518 return;
2519
2520 /* clear last_governor for all inactive policies */
2521 read_lock_irqsave(&cpufreq_driver_lock, flags);
2522 for_each_inactive_policy(policy) {
2523 if (!strcmp(policy->last_governor, governor->name)) {
2524 policy->governor = NULL;
2525 strcpy(policy->last_governor, "\0");
2526 }
2527 }
2528 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2529
2530 mutex_lock(&cpufreq_governor_mutex);
2531 list_del(&governor->governor_list);
2532 mutex_unlock(&cpufreq_governor_mutex);
2533}
2534EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2535
2536
2537/*********************************************************************
2538 * POLICY INTERFACE *
2539 *********************************************************************/
2540
2541/**
2542 * cpufreq_get_policy - get the current cpufreq_policy
2543 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2544 * is written
2545 * @cpu: CPU to find the policy for
2546 *
2547 * Reads the current cpufreq policy.
2548 */
2549int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2550{
2551 struct cpufreq_policy *cpu_policy;
2552 if (!policy)
2553 return -EINVAL;
2554
2555 cpu_policy = cpufreq_cpu_get(cpu);
2556 if (!cpu_policy)
2557 return -EINVAL;
2558
2559 memcpy(policy, cpu_policy, sizeof(*policy));
2560
2561 cpufreq_cpu_put(cpu_policy);
2562 return 0;
2563}
2564EXPORT_SYMBOL(cpufreq_get_policy);
2565
2566/**
2567 * cpufreq_set_policy - Modify cpufreq policy parameters.
2568 * @policy: Policy object to modify.
2569 * @new_gov: Policy governor pointer.
2570 * @new_pol: Policy value (for drivers with built-in governors).
2571 *
2572 * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
2573 * limits to be set for the policy, update @policy with the verified limits
2574 * values and either invoke the driver's ->setpolicy() callback (if present) or
2575 * carry out a governor update for @policy. That is, run the current governor's
2576 * ->limits() callback (if @new_gov points to the same object as the one in
2577 * @policy) or replace the governor for @policy with @new_gov.
2578 *
2579 * The cpuinfo part of @policy is not updated by this function.
2580 */
2581static int cpufreq_set_policy(struct cpufreq_policy *policy,
2582 struct cpufreq_governor *new_gov,
2583 unsigned int new_pol)
2584{
2585 struct cpufreq_policy_data new_data;
2586 struct cpufreq_governor *old_gov;
2587 int ret;
2588
2589 memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2590 new_data.freq_table = policy->freq_table;
2591 new_data.cpu = policy->cpu;
2592 /*
2593 * PM QoS framework collects all the requests from users and provide us
2594 * the final aggregated value here.
2595 */
2596 new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2597 new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2598
2599 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2600 new_data.cpu, new_data.min, new_data.max);
2601
2602 /*
2603 * Verify that the CPU speed can be set within these limits and make sure
2604 * that min <= max.
2605 */
2606 ret = cpufreq_driver->verify(&new_data);
2607 if (ret)
2608 return ret;
2609
2610 /*
2611 * Resolve policy min/max to available frequencies. It ensures
2612 * no frequency resolution will neither overshoot the requested maximum
2613 * nor undershoot the requested minimum.
2614 */
2615 policy->min = new_data.min;
2616 policy->max = new_data.max;
2617 policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
2618 policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
2619 trace_cpu_frequency_limits(policy);
2620
2621 policy->cached_target_freq = UINT_MAX;
2622
2623 pr_debug("new min and max freqs are %u - %u kHz\n",
2624 policy->min, policy->max);
2625
2626 if (cpufreq_driver->setpolicy) {
2627 policy->policy = new_pol;
2628 pr_debug("setting range\n");
2629 return cpufreq_driver->setpolicy(policy);
2630 }
2631
2632 if (new_gov == policy->governor) {
2633 pr_debug("governor limits update\n");
2634 cpufreq_governor_limits(policy);
2635 return 0;
2636 }
2637
2638 pr_debug("governor switch\n");
2639
2640 /* save old, working values */
2641 old_gov = policy->governor;
2642 /* end old governor */
2643 if (old_gov) {
2644 cpufreq_stop_governor(policy);
2645 cpufreq_exit_governor(policy);
2646 }
2647
2648 /* start new governor */
2649 policy->governor = new_gov;
2650 ret = cpufreq_init_governor(policy);
2651 if (!ret) {
2652 ret = cpufreq_start_governor(policy);
2653 if (!ret) {
2654 pr_debug("governor change\n");
2655 return 0;
2656 }
2657 cpufreq_exit_governor(policy);
2658 }
2659
2660 /* new governor failed, so re-start old one */
2661 pr_debug("starting governor %s failed\n", policy->governor->name);
2662 if (old_gov) {
2663 policy->governor = old_gov;
2664 if (cpufreq_init_governor(policy))
2665 policy->governor = NULL;
2666 else
2667 cpufreq_start_governor(policy);
2668 }
2669
2670 return ret;
2671}
2672
2673/**
2674 * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2675 * @cpu: CPU to re-evaluate the policy for.
2676 *
2677 * Update the current frequency for the cpufreq policy of @cpu and use
2678 * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2679 * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2680 * for the policy in question, among other things.
2681 */
2682void cpufreq_update_policy(unsigned int cpu)
2683{
2684 struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2685
2686 if (!policy)
2687 return;
2688
2689 /*
2690 * BIOS might change freq behind our back
2691 * -> ask driver for current freq and notify governors about a change
2692 */
2693 if (cpufreq_driver->get && has_target() &&
2694 (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2695 goto unlock;
2696
2697 refresh_frequency_limits(policy);
2698
2699unlock:
2700 cpufreq_cpu_release(policy);
2701}
2702EXPORT_SYMBOL(cpufreq_update_policy);
2703
2704/**
2705 * cpufreq_update_limits - Update policy limits for a given CPU.
2706 * @cpu: CPU to update the policy limits for.
2707 *
2708 * Invoke the driver's ->update_limits callback if present or call
2709 * cpufreq_update_policy() for @cpu.
2710 */
2711void cpufreq_update_limits(unsigned int cpu)
2712{
2713 if (cpufreq_driver->update_limits)
2714 cpufreq_driver->update_limits(cpu);
2715 else
2716 cpufreq_update_policy(cpu);
2717}
2718EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2719
2720/*********************************************************************
2721 * BOOST *
2722 *********************************************************************/
2723static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
2724{
2725 int ret;
2726
2727 if (!policy->freq_table)
2728 return -ENXIO;
2729
2730 ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
2731 if (ret) {
2732 pr_err("%s: Policy frequency update failed\n", __func__);
2733 return ret;
2734 }
2735
2736 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2737 if (ret < 0)
2738 return ret;
2739
2740 return 0;
2741}
2742
2743int cpufreq_boost_trigger_state(int state)
2744{
2745 struct cpufreq_policy *policy;
2746 unsigned long flags;
2747 int ret = 0;
2748
2749 if (cpufreq_driver->boost_enabled == state)
2750 return 0;
2751
2752 write_lock_irqsave(&cpufreq_driver_lock, flags);
2753 cpufreq_driver->boost_enabled = state;
2754 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2755
2756 cpus_read_lock();
2757 for_each_active_policy(policy) {
2758 ret = cpufreq_driver->set_boost(policy, state);
2759 if (ret)
2760 goto err_reset_state;
2761
2762 policy->boost_enabled = state;
2763 }
2764 cpus_read_unlock();
2765
2766 return 0;
2767
2768err_reset_state:
2769 cpus_read_unlock();
2770
2771 write_lock_irqsave(&cpufreq_driver_lock, flags);
2772 cpufreq_driver->boost_enabled = !state;
2773 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2774
2775 pr_err("%s: Cannot %s BOOST\n",
2776 __func__, state ? "enable" : "disable");
2777
2778 return ret;
2779}
2780
2781static bool cpufreq_boost_supported(void)
2782{
2783 return cpufreq_driver->set_boost;
2784}
2785
2786static int create_boost_sysfs_file(void)
2787{
2788 int ret;
2789
2790 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2791 if (ret)
2792 pr_err("%s: cannot register global BOOST sysfs file\n",
2793 __func__);
2794
2795 return ret;
2796}
2797
2798static void remove_boost_sysfs_file(void)
2799{
2800 if (cpufreq_boost_supported())
2801 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2802}
2803
2804int cpufreq_enable_boost_support(void)
2805{
2806 if (!cpufreq_driver)
2807 return -EINVAL;
2808
2809 if (cpufreq_boost_supported())
2810 return 0;
2811
2812 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2813
2814 /* This will get removed on driver unregister */
2815 return create_boost_sysfs_file();
2816}
2817EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2818
2819int cpufreq_boost_enabled(void)
2820{
2821 return cpufreq_driver->boost_enabled;
2822}
2823EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2824
2825/*********************************************************************
2826 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2827 *********************************************************************/
2828static enum cpuhp_state hp_online;
2829
2830static int cpuhp_cpufreq_online(unsigned int cpu)
2831{
2832 cpufreq_online(cpu);
2833
2834 return 0;
2835}
2836
2837static int cpuhp_cpufreq_offline(unsigned int cpu)
2838{
2839 cpufreq_offline(cpu);
2840
2841 return 0;
2842}
2843
2844/**
2845 * cpufreq_register_driver - register a CPU Frequency driver
2846 * @driver_data: A struct cpufreq_driver containing the values#
2847 * submitted by the CPU Frequency driver.
2848 *
2849 * Registers a CPU Frequency driver to this core code. This code
2850 * returns zero on success, -EEXIST when another driver got here first
2851 * (and isn't unregistered in the meantime).
2852 *
2853 */
2854int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2855{
2856 unsigned long flags;
2857 int ret;
2858
2859 if (cpufreq_disabled())
2860 return -ENODEV;
2861
2862 /*
2863 * The cpufreq core depends heavily on the availability of device
2864 * structure, make sure they are available before proceeding further.
2865 */
2866 if (!get_cpu_device(0))
2867 return -EPROBE_DEFER;
2868
2869 if (!driver_data || !driver_data->verify || !driver_data->init ||
2870 !(driver_data->setpolicy || driver_data->target_index ||
2871 driver_data->target) ||
2872 (driver_data->setpolicy && (driver_data->target_index ||
2873 driver_data->target)) ||
2874 (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2875 (!driver_data->online != !driver_data->offline) ||
2876 (driver_data->adjust_perf && !driver_data->fast_switch))
2877 return -EINVAL;
2878
2879 pr_debug("trying to register driver %s\n", driver_data->name);
2880
2881 /* Protect against concurrent CPU online/offline. */
2882 cpus_read_lock();
2883
2884 write_lock_irqsave(&cpufreq_driver_lock, flags);
2885 if (cpufreq_driver) {
2886 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2887 ret = -EEXIST;
2888 goto out;
2889 }
2890 cpufreq_driver = driver_data;
2891 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2892
2893 /*
2894 * Mark support for the scheduler's frequency invariance engine for
2895 * drivers that implement target(), target_index() or fast_switch().
2896 */
2897 if (!cpufreq_driver->setpolicy) {
2898 static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
2899 pr_debug("supports frequency invariance");
2900 }
2901
2902 if (driver_data->setpolicy)
2903 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2904
2905 if (cpufreq_boost_supported()) {
2906 ret = create_boost_sysfs_file();
2907 if (ret)
2908 goto err_null_driver;
2909 }
2910
2911 ret = subsys_interface_register(&cpufreq_interface);
2912 if (ret)
2913 goto err_boost_unreg;
2914
2915 if (unlikely(list_empty(&cpufreq_policy_list))) {
2916 /* if all ->init() calls failed, unregister */
2917 ret = -ENODEV;
2918 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2919 driver_data->name);
2920 goto err_if_unreg;
2921 }
2922
2923 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2924 "cpufreq:online",
2925 cpuhp_cpufreq_online,
2926 cpuhp_cpufreq_offline);
2927 if (ret < 0)
2928 goto err_if_unreg;
2929 hp_online = ret;
2930 ret = 0;
2931
2932 pr_debug("driver %s up and running\n", driver_data->name);
2933 goto out;
2934
2935err_if_unreg:
2936 subsys_interface_unregister(&cpufreq_interface);
2937err_boost_unreg:
2938 remove_boost_sysfs_file();
2939err_null_driver:
2940 write_lock_irqsave(&cpufreq_driver_lock, flags);
2941 cpufreq_driver = NULL;
2942 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2943out:
2944 cpus_read_unlock();
2945 return ret;
2946}
2947EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2948
2949/*
2950 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2951 *
2952 * Unregister the current CPUFreq driver. Only call this if you have
2953 * the right to do so, i.e. if you have succeeded in initialising before!
2954 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2955 * currently not initialised.
2956 */
2957void cpufreq_unregister_driver(struct cpufreq_driver *driver)
2958{
2959 unsigned long flags;
2960
2961 if (WARN_ON(!cpufreq_driver || (driver != cpufreq_driver)))
2962 return;
2963
2964 pr_debug("unregistering driver %s\n", driver->name);
2965
2966 /* Protect against concurrent cpu hotplug */
2967 cpus_read_lock();
2968 subsys_interface_unregister(&cpufreq_interface);
2969 remove_boost_sysfs_file();
2970 static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
2971 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2972
2973 write_lock_irqsave(&cpufreq_driver_lock, flags);
2974
2975 cpufreq_driver = NULL;
2976
2977 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2978 cpus_read_unlock();
2979}
2980EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2981
2982static int __init cpufreq_core_init(void)
2983{
2984 struct cpufreq_governor *gov = cpufreq_default_governor();
2985 struct device *dev_root;
2986
2987 if (cpufreq_disabled())
2988 return -ENODEV;
2989
2990 dev_root = bus_get_dev_root(&cpu_subsys);
2991 if (dev_root) {
2992 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &dev_root->kobj);
2993 put_device(dev_root);
2994 }
2995 BUG_ON(!cpufreq_global_kobject);
2996
2997 if (!strlen(default_governor))
2998 strscpy(default_governor, gov->name, CPUFREQ_NAME_LEN);
2999
3000 return 0;
3001}
3002module_param(off, int, 0444);
3003module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
3004core_initcall(cpufreq_core_init);
1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 *
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10 * Fix handling for CPU hotplug -- affected CPUs
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 *
16 */
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/notifier.h>
22#include <linux/cpufreq.h>
23#include <linux/delay.h>
24#include <linux/interrupt.h>
25#include <linux/spinlock.h>
26#include <linux/device.h>
27#include <linux/slab.h>
28#include <linux/cpu.h>
29#include <linux/completion.h>
30#include <linux/mutex.h>
31#include <linux/syscore_ops.h>
32
33#include <trace/events/power.h>
34
35/**
36 * The "cpufreq driver" - the arch- or hardware-dependent low
37 * level driver of CPUFreq support, and its spinlock. This lock
38 * also protects the cpufreq_cpu_data array.
39 */
40static struct cpufreq_driver *cpufreq_driver;
41static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42#ifdef CONFIG_HOTPLUG_CPU
43/* This one keeps track of the previously set governor of a removed CPU */
44static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
45#endif
46static DEFINE_SPINLOCK(cpufreq_driver_lock);
47
48/*
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
51 *
52 * The rules for this semaphore:
53 * - Any routine that wants to read from the policy structure will
54 * do a down_read on this semaphore.
55 * - Any routine that will write to the policy structure and/or may take away
56 * the policy altogether (eg. CPU hotplug), will hold this lock in write
57 * mode before doing so.
58 *
59 * Additional rules:
60 * - All holders of the lock should check to make sure that the CPU they
61 * are concerned with are online after they get the lock.
62 * - Governor routines that can be called in cpufreq hotplug path should not
63 * take this sem as top level hotplug notifier handler takes this.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
66 */
67static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
68static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
69
70#define lock_policy_rwsem(mode, cpu) \
71static int lock_policy_rwsem_##mode \
72(int cpu) \
73{ \
74 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
75 BUG_ON(policy_cpu == -1); \
76 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
77 if (unlikely(!cpu_online(cpu))) { \
78 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
79 return -1; \
80 } \
81 \
82 return 0; \
83}
84
85lock_policy_rwsem(read, cpu);
86
87lock_policy_rwsem(write, cpu);
88
89static void unlock_policy_rwsem_read(int cpu)
90{
91 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
94}
95
96static void unlock_policy_rwsem_write(int cpu)
97{
98 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
99 BUG_ON(policy_cpu == -1);
100 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
101}
102
103
104/* internal prototypes */
105static int __cpufreq_governor(struct cpufreq_policy *policy,
106 unsigned int event);
107static unsigned int __cpufreq_get(unsigned int cpu);
108static void handle_update(struct work_struct *work);
109
110/**
111 * Two notifier lists: the "policy" list is involved in the
112 * validation process for a new CPU frequency policy; the
113 * "transition" list for kernel code that needs to handle
114 * changes to devices when the CPU clock speed changes.
115 * The mutex locks both lists.
116 */
117static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
118static struct srcu_notifier_head cpufreq_transition_notifier_list;
119
120static bool init_cpufreq_transition_notifier_list_called;
121static int __init init_cpufreq_transition_notifier_list(void)
122{
123 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
124 init_cpufreq_transition_notifier_list_called = true;
125 return 0;
126}
127pure_initcall(init_cpufreq_transition_notifier_list);
128
129static int off __read_mostly;
130int cpufreq_disabled(void)
131{
132 return off;
133}
134void disable_cpufreq(void)
135{
136 off = 1;
137}
138static LIST_HEAD(cpufreq_governor_list);
139static DEFINE_MUTEX(cpufreq_governor_mutex);
140
141struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
142{
143 struct cpufreq_policy *data;
144 unsigned long flags;
145
146 if (cpu >= nr_cpu_ids)
147 goto err_out;
148
149 /* get the cpufreq driver */
150 spin_lock_irqsave(&cpufreq_driver_lock, flags);
151
152 if (!cpufreq_driver)
153 goto err_out_unlock;
154
155 if (!try_module_get(cpufreq_driver->owner))
156 goto err_out_unlock;
157
158
159 /* get the CPU */
160 data = per_cpu(cpufreq_cpu_data, cpu);
161
162 if (!data)
163 goto err_out_put_module;
164
165 if (!kobject_get(&data->kobj))
166 goto err_out_put_module;
167
168 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
169 return data;
170
171err_out_put_module:
172 module_put(cpufreq_driver->owner);
173err_out_unlock:
174 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
175err_out:
176 return NULL;
177}
178EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
179
180
181void cpufreq_cpu_put(struct cpufreq_policy *data)
182{
183 kobject_put(&data->kobj);
184 module_put(cpufreq_driver->owner);
185}
186EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
187
188
189/*********************************************************************
190 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
191 *********************************************************************/
192
193/**
194 * adjust_jiffies - adjust the system "loops_per_jiffy"
195 *
196 * This function alters the system "loops_per_jiffy" for the clock
197 * speed change. Note that loops_per_jiffy cannot be updated on SMP
198 * systems as each CPU might be scaled differently. So, use the arch
199 * per-CPU loops_per_jiffy value wherever possible.
200 */
201#ifndef CONFIG_SMP
202static unsigned long l_p_j_ref;
203static unsigned int l_p_j_ref_freq;
204
205static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
206{
207 if (ci->flags & CPUFREQ_CONST_LOOPS)
208 return;
209
210 if (!l_p_j_ref_freq) {
211 l_p_j_ref = loops_per_jiffy;
212 l_p_j_ref_freq = ci->old;
213 pr_debug("saving %lu as reference value for loops_per_jiffy; "
214 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
215 }
216 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
217 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
218 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
219 ci->new);
220 pr_debug("scaling loops_per_jiffy to %lu "
221 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
222 }
223}
224#else
225static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
226{
227 return;
228}
229#endif
230
231
232/**
233 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
234 * on frequency transition.
235 *
236 * This function calls the transition notifiers and the "adjust_jiffies"
237 * function. It is called twice on all CPU frequency changes that have
238 * external effects.
239 */
240void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
241{
242 struct cpufreq_policy *policy;
243
244 BUG_ON(irqs_disabled());
245
246 freqs->flags = cpufreq_driver->flags;
247 pr_debug("notification %u of frequency transition to %u kHz\n",
248 state, freqs->new);
249
250 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
251 switch (state) {
252
253 case CPUFREQ_PRECHANGE:
254 /* detect if the driver reported a value as "old frequency"
255 * which is not equal to what the cpufreq core thinks is
256 * "old frequency".
257 */
258 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
259 if ((policy) && (policy->cpu == freqs->cpu) &&
260 (policy->cur) && (policy->cur != freqs->old)) {
261 pr_debug("Warning: CPU frequency is"
262 " %u, cpufreq assumed %u kHz.\n",
263 freqs->old, policy->cur);
264 freqs->old = policy->cur;
265 }
266 }
267 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
268 CPUFREQ_PRECHANGE, freqs);
269 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
270 break;
271
272 case CPUFREQ_POSTCHANGE:
273 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
274 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
275 (unsigned long)freqs->cpu);
276 trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
277 trace_cpu_frequency(freqs->new, freqs->cpu);
278 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
279 CPUFREQ_POSTCHANGE, freqs);
280 if (likely(policy) && likely(policy->cpu == freqs->cpu))
281 policy->cur = freqs->new;
282 break;
283 }
284}
285EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
286
287
288
289/*********************************************************************
290 * SYSFS INTERFACE *
291 *********************************************************************/
292
293static struct cpufreq_governor *__find_governor(const char *str_governor)
294{
295 struct cpufreq_governor *t;
296
297 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
298 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
299 return t;
300
301 return NULL;
302}
303
304/**
305 * cpufreq_parse_governor - parse a governor string
306 */
307static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
308 struct cpufreq_governor **governor)
309{
310 int err = -EINVAL;
311
312 if (!cpufreq_driver)
313 goto out;
314
315 if (cpufreq_driver->setpolicy) {
316 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
317 *policy = CPUFREQ_POLICY_PERFORMANCE;
318 err = 0;
319 } else if (!strnicmp(str_governor, "powersave",
320 CPUFREQ_NAME_LEN)) {
321 *policy = CPUFREQ_POLICY_POWERSAVE;
322 err = 0;
323 }
324 } else if (cpufreq_driver->target) {
325 struct cpufreq_governor *t;
326
327 mutex_lock(&cpufreq_governor_mutex);
328
329 t = __find_governor(str_governor);
330
331 if (t == NULL) {
332 int ret;
333
334 mutex_unlock(&cpufreq_governor_mutex);
335 ret = request_module("cpufreq_%s", str_governor);
336 mutex_lock(&cpufreq_governor_mutex);
337
338 if (ret == 0)
339 t = __find_governor(str_governor);
340 }
341
342 if (t != NULL) {
343 *governor = t;
344 err = 0;
345 }
346
347 mutex_unlock(&cpufreq_governor_mutex);
348 }
349out:
350 return err;
351}
352
353
354/**
355 * cpufreq_per_cpu_attr_read() / show_##file_name() -
356 * print out cpufreq information
357 *
358 * Write out information from cpufreq_driver->policy[cpu]; object must be
359 * "unsigned int".
360 */
361
362#define show_one(file_name, object) \
363static ssize_t show_##file_name \
364(struct cpufreq_policy *policy, char *buf) \
365{ \
366 return sprintf(buf, "%u\n", policy->object); \
367}
368
369show_one(cpuinfo_min_freq, cpuinfo.min_freq);
370show_one(cpuinfo_max_freq, cpuinfo.max_freq);
371show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
372show_one(scaling_min_freq, min);
373show_one(scaling_max_freq, max);
374show_one(scaling_cur_freq, cur);
375
376static int __cpufreq_set_policy(struct cpufreq_policy *data,
377 struct cpufreq_policy *policy);
378
379/**
380 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
381 */
382#define store_one(file_name, object) \
383static ssize_t store_##file_name \
384(struct cpufreq_policy *policy, const char *buf, size_t count) \
385{ \
386 unsigned int ret = -EINVAL; \
387 struct cpufreq_policy new_policy; \
388 \
389 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
390 if (ret) \
391 return -EINVAL; \
392 \
393 ret = sscanf(buf, "%u", &new_policy.object); \
394 if (ret != 1) \
395 return -EINVAL; \
396 \
397 ret = __cpufreq_set_policy(policy, &new_policy); \
398 policy->user_policy.object = policy->object; \
399 \
400 return ret ? ret : count; \
401}
402
403store_one(scaling_min_freq, min);
404store_one(scaling_max_freq, max);
405
406/**
407 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
408 */
409static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
410 char *buf)
411{
412 unsigned int cur_freq = __cpufreq_get(policy->cpu);
413 if (!cur_freq)
414 return sprintf(buf, "<unknown>");
415 return sprintf(buf, "%u\n", cur_freq);
416}
417
418
419/**
420 * show_scaling_governor - show the current policy for the specified CPU
421 */
422static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
423{
424 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
425 return sprintf(buf, "powersave\n");
426 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
427 return sprintf(buf, "performance\n");
428 else if (policy->governor)
429 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
430 policy->governor->name);
431 return -EINVAL;
432}
433
434
435/**
436 * store_scaling_governor - store policy for the specified CPU
437 */
438static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
439 const char *buf, size_t count)
440{
441 unsigned int ret = -EINVAL;
442 char str_governor[16];
443 struct cpufreq_policy new_policy;
444
445 ret = cpufreq_get_policy(&new_policy, policy->cpu);
446 if (ret)
447 return ret;
448
449 ret = sscanf(buf, "%15s", str_governor);
450 if (ret != 1)
451 return -EINVAL;
452
453 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
454 &new_policy.governor))
455 return -EINVAL;
456
457 /* Do not use cpufreq_set_policy here or the user_policy.max
458 will be wrongly overridden */
459 ret = __cpufreq_set_policy(policy, &new_policy);
460
461 policy->user_policy.policy = policy->policy;
462 policy->user_policy.governor = policy->governor;
463
464 if (ret)
465 return ret;
466 else
467 return count;
468}
469
470/**
471 * show_scaling_driver - show the cpufreq driver currently loaded
472 */
473static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
474{
475 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
476}
477
478/**
479 * show_scaling_available_governors - show the available CPUfreq governors
480 */
481static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
482 char *buf)
483{
484 ssize_t i = 0;
485 struct cpufreq_governor *t;
486
487 if (!cpufreq_driver->target) {
488 i += sprintf(buf, "performance powersave");
489 goto out;
490 }
491
492 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
493 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
494 - (CPUFREQ_NAME_LEN + 2)))
495 goto out;
496 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
497 }
498out:
499 i += sprintf(&buf[i], "\n");
500 return i;
501}
502
503static ssize_t show_cpus(const struct cpumask *mask, char *buf)
504{
505 ssize_t i = 0;
506 unsigned int cpu;
507
508 for_each_cpu(cpu, mask) {
509 if (i)
510 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
511 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
512 if (i >= (PAGE_SIZE - 5))
513 break;
514 }
515 i += sprintf(&buf[i], "\n");
516 return i;
517}
518
519/**
520 * show_related_cpus - show the CPUs affected by each transition even if
521 * hw coordination is in use
522 */
523static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
524{
525 if (cpumask_empty(policy->related_cpus))
526 return show_cpus(policy->cpus, buf);
527 return show_cpus(policy->related_cpus, buf);
528}
529
530/**
531 * show_affected_cpus - show the CPUs affected by each transition
532 */
533static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
534{
535 return show_cpus(policy->cpus, buf);
536}
537
538static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
539 const char *buf, size_t count)
540{
541 unsigned int freq = 0;
542 unsigned int ret;
543
544 if (!policy->governor || !policy->governor->store_setspeed)
545 return -EINVAL;
546
547 ret = sscanf(buf, "%u", &freq);
548 if (ret != 1)
549 return -EINVAL;
550
551 policy->governor->store_setspeed(policy, freq);
552
553 return count;
554}
555
556static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
557{
558 if (!policy->governor || !policy->governor->show_setspeed)
559 return sprintf(buf, "<unsupported>\n");
560
561 return policy->governor->show_setspeed(policy, buf);
562}
563
564/**
565 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
566 */
567static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
568{
569 unsigned int limit;
570 int ret;
571 if (cpufreq_driver->bios_limit) {
572 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
573 if (!ret)
574 return sprintf(buf, "%u\n", limit);
575 }
576 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
577}
578
579cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
580cpufreq_freq_attr_ro(cpuinfo_min_freq);
581cpufreq_freq_attr_ro(cpuinfo_max_freq);
582cpufreq_freq_attr_ro(cpuinfo_transition_latency);
583cpufreq_freq_attr_ro(scaling_available_governors);
584cpufreq_freq_attr_ro(scaling_driver);
585cpufreq_freq_attr_ro(scaling_cur_freq);
586cpufreq_freq_attr_ro(bios_limit);
587cpufreq_freq_attr_ro(related_cpus);
588cpufreq_freq_attr_ro(affected_cpus);
589cpufreq_freq_attr_rw(scaling_min_freq);
590cpufreq_freq_attr_rw(scaling_max_freq);
591cpufreq_freq_attr_rw(scaling_governor);
592cpufreq_freq_attr_rw(scaling_setspeed);
593
594static struct attribute *default_attrs[] = {
595 &cpuinfo_min_freq.attr,
596 &cpuinfo_max_freq.attr,
597 &cpuinfo_transition_latency.attr,
598 &scaling_min_freq.attr,
599 &scaling_max_freq.attr,
600 &affected_cpus.attr,
601 &related_cpus.attr,
602 &scaling_governor.attr,
603 &scaling_driver.attr,
604 &scaling_available_governors.attr,
605 &scaling_setspeed.attr,
606 NULL
607};
608
609struct kobject *cpufreq_global_kobject;
610EXPORT_SYMBOL(cpufreq_global_kobject);
611
612#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
613#define to_attr(a) container_of(a, struct freq_attr, attr)
614
615static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
616{
617 struct cpufreq_policy *policy = to_policy(kobj);
618 struct freq_attr *fattr = to_attr(attr);
619 ssize_t ret = -EINVAL;
620 policy = cpufreq_cpu_get(policy->cpu);
621 if (!policy)
622 goto no_policy;
623
624 if (lock_policy_rwsem_read(policy->cpu) < 0)
625 goto fail;
626
627 if (fattr->show)
628 ret = fattr->show(policy, buf);
629 else
630 ret = -EIO;
631
632 unlock_policy_rwsem_read(policy->cpu);
633fail:
634 cpufreq_cpu_put(policy);
635no_policy:
636 return ret;
637}
638
639static ssize_t store(struct kobject *kobj, struct attribute *attr,
640 const char *buf, size_t count)
641{
642 struct cpufreq_policy *policy = to_policy(kobj);
643 struct freq_attr *fattr = to_attr(attr);
644 ssize_t ret = -EINVAL;
645 policy = cpufreq_cpu_get(policy->cpu);
646 if (!policy)
647 goto no_policy;
648
649 if (lock_policy_rwsem_write(policy->cpu) < 0)
650 goto fail;
651
652 if (fattr->store)
653 ret = fattr->store(policy, buf, count);
654 else
655 ret = -EIO;
656
657 unlock_policy_rwsem_write(policy->cpu);
658fail:
659 cpufreq_cpu_put(policy);
660no_policy:
661 return ret;
662}
663
664static void cpufreq_sysfs_release(struct kobject *kobj)
665{
666 struct cpufreq_policy *policy = to_policy(kobj);
667 pr_debug("last reference is dropped\n");
668 complete(&policy->kobj_unregister);
669}
670
671static const struct sysfs_ops sysfs_ops = {
672 .show = show,
673 .store = store,
674};
675
676static struct kobj_type ktype_cpufreq = {
677 .sysfs_ops = &sysfs_ops,
678 .default_attrs = default_attrs,
679 .release = cpufreq_sysfs_release,
680};
681
682/*
683 * Returns:
684 * Negative: Failure
685 * 0: Success
686 * Positive: When we have a managed CPU and the sysfs got symlinked
687 */
688static int cpufreq_add_dev_policy(unsigned int cpu,
689 struct cpufreq_policy *policy,
690 struct device *dev)
691{
692 int ret = 0;
693#ifdef CONFIG_SMP
694 unsigned long flags;
695 unsigned int j;
696#ifdef CONFIG_HOTPLUG_CPU
697 struct cpufreq_governor *gov;
698
699 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
700 if (gov) {
701 policy->governor = gov;
702 pr_debug("Restoring governor %s for cpu %d\n",
703 policy->governor->name, cpu);
704 }
705#endif
706
707 for_each_cpu(j, policy->cpus) {
708 struct cpufreq_policy *managed_policy;
709
710 if (cpu == j)
711 continue;
712
713 /* Check for existing affected CPUs.
714 * They may not be aware of it due to CPU Hotplug.
715 * cpufreq_cpu_put is called when the device is removed
716 * in __cpufreq_remove_dev()
717 */
718 managed_policy = cpufreq_cpu_get(j);
719 if (unlikely(managed_policy)) {
720
721 /* Set proper policy_cpu */
722 unlock_policy_rwsem_write(cpu);
723 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
724
725 if (lock_policy_rwsem_write(cpu) < 0) {
726 /* Should not go through policy unlock path */
727 if (cpufreq_driver->exit)
728 cpufreq_driver->exit(policy);
729 cpufreq_cpu_put(managed_policy);
730 return -EBUSY;
731 }
732
733 spin_lock_irqsave(&cpufreq_driver_lock, flags);
734 cpumask_copy(managed_policy->cpus, policy->cpus);
735 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
736 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
737
738 pr_debug("CPU already managed, adding link\n");
739 ret = sysfs_create_link(&dev->kobj,
740 &managed_policy->kobj,
741 "cpufreq");
742 if (ret)
743 cpufreq_cpu_put(managed_policy);
744 /*
745 * Success. We only needed to be added to the mask.
746 * Call driver->exit() because only the cpu parent of
747 * the kobj needed to call init().
748 */
749 if (cpufreq_driver->exit)
750 cpufreq_driver->exit(policy);
751
752 if (!ret)
753 return 1;
754 else
755 return ret;
756 }
757 }
758#endif
759 return ret;
760}
761
762
763/* symlink affected CPUs */
764static int cpufreq_add_dev_symlink(unsigned int cpu,
765 struct cpufreq_policy *policy)
766{
767 unsigned int j;
768 int ret = 0;
769
770 for_each_cpu(j, policy->cpus) {
771 struct cpufreq_policy *managed_policy;
772 struct device *cpu_dev;
773
774 if (j == cpu)
775 continue;
776 if (!cpu_online(j))
777 continue;
778
779 pr_debug("CPU %u already managed, adding link\n", j);
780 managed_policy = cpufreq_cpu_get(cpu);
781 cpu_dev = get_cpu_device(j);
782 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
783 "cpufreq");
784 if (ret) {
785 cpufreq_cpu_put(managed_policy);
786 return ret;
787 }
788 }
789 return ret;
790}
791
792static int cpufreq_add_dev_interface(unsigned int cpu,
793 struct cpufreq_policy *policy,
794 struct device *dev)
795{
796 struct cpufreq_policy new_policy;
797 struct freq_attr **drv_attr;
798 unsigned long flags;
799 int ret = 0;
800 unsigned int j;
801
802 /* prepare interface data */
803 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
804 &dev->kobj, "cpufreq");
805 if (ret)
806 return ret;
807
808 /* set up files for this cpu device */
809 drv_attr = cpufreq_driver->attr;
810 while ((drv_attr) && (*drv_attr)) {
811 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
812 if (ret)
813 goto err_out_kobj_put;
814 drv_attr++;
815 }
816 if (cpufreq_driver->get) {
817 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
818 if (ret)
819 goto err_out_kobj_put;
820 }
821 if (cpufreq_driver->target) {
822 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
823 if (ret)
824 goto err_out_kobj_put;
825 }
826 if (cpufreq_driver->bios_limit) {
827 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
828 if (ret)
829 goto err_out_kobj_put;
830 }
831
832 spin_lock_irqsave(&cpufreq_driver_lock, flags);
833 for_each_cpu(j, policy->cpus) {
834 if (!cpu_online(j))
835 continue;
836 per_cpu(cpufreq_cpu_data, j) = policy;
837 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
838 }
839 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
840
841 ret = cpufreq_add_dev_symlink(cpu, policy);
842 if (ret)
843 goto err_out_kobj_put;
844
845 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
846 /* assure that the starting sequence is run in __cpufreq_set_policy */
847 policy->governor = NULL;
848
849 /* set default policy */
850 ret = __cpufreq_set_policy(policy, &new_policy);
851 policy->user_policy.policy = policy->policy;
852 policy->user_policy.governor = policy->governor;
853
854 if (ret) {
855 pr_debug("setting policy failed\n");
856 if (cpufreq_driver->exit)
857 cpufreq_driver->exit(policy);
858 }
859 return ret;
860
861err_out_kobj_put:
862 kobject_put(&policy->kobj);
863 wait_for_completion(&policy->kobj_unregister);
864 return ret;
865}
866
867
868/**
869 * cpufreq_add_dev - add a CPU device
870 *
871 * Adds the cpufreq interface for a CPU device.
872 *
873 * The Oracle says: try running cpufreq registration/unregistration concurrently
874 * with with cpu hotplugging and all hell will break loose. Tried to clean this
875 * mess up, but more thorough testing is needed. - Mathieu
876 */
877static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
878{
879 unsigned int cpu = dev->id;
880 int ret = 0, found = 0;
881 struct cpufreq_policy *policy;
882 unsigned long flags;
883 unsigned int j;
884#ifdef CONFIG_HOTPLUG_CPU
885 int sibling;
886#endif
887
888 if (cpu_is_offline(cpu))
889 return 0;
890
891 pr_debug("adding CPU %u\n", cpu);
892
893#ifdef CONFIG_SMP
894 /* check whether a different CPU already registered this
895 * CPU because it is in the same boat. */
896 policy = cpufreq_cpu_get(cpu);
897 if (unlikely(policy)) {
898 cpufreq_cpu_put(policy);
899 return 0;
900 }
901#endif
902
903 if (!try_module_get(cpufreq_driver->owner)) {
904 ret = -EINVAL;
905 goto module_out;
906 }
907
908 ret = -ENOMEM;
909 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
910 if (!policy)
911 goto nomem_out;
912
913 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
914 goto err_free_policy;
915
916 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
917 goto err_free_cpumask;
918
919 policy->cpu = cpu;
920 cpumask_copy(policy->cpus, cpumask_of(cpu));
921
922 /* Initially set CPU itself as the policy_cpu */
923 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
924 ret = (lock_policy_rwsem_write(cpu) < 0);
925 WARN_ON(ret);
926
927 init_completion(&policy->kobj_unregister);
928 INIT_WORK(&policy->update, handle_update);
929
930 /* Set governor before ->init, so that driver could check it */
931#ifdef CONFIG_HOTPLUG_CPU
932 for_each_online_cpu(sibling) {
933 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
934 if (cp && cp->governor &&
935 (cpumask_test_cpu(cpu, cp->related_cpus))) {
936 policy->governor = cp->governor;
937 found = 1;
938 break;
939 }
940 }
941#endif
942 if (!found)
943 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
944 /* call driver. From then on the cpufreq must be able
945 * to accept all calls to ->verify and ->setpolicy for this CPU
946 */
947 ret = cpufreq_driver->init(policy);
948 if (ret) {
949 pr_debug("initialization failed\n");
950 goto err_unlock_policy;
951 }
952 policy->user_policy.min = policy->min;
953 policy->user_policy.max = policy->max;
954
955 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
956 CPUFREQ_START, policy);
957
958 ret = cpufreq_add_dev_policy(cpu, policy, dev);
959 if (ret) {
960 if (ret > 0)
961 /* This is a managed cpu, symlink created,
962 exit with 0 */
963 ret = 0;
964 goto err_unlock_policy;
965 }
966
967 ret = cpufreq_add_dev_interface(cpu, policy, dev);
968 if (ret)
969 goto err_out_unregister;
970
971 unlock_policy_rwsem_write(cpu);
972
973 kobject_uevent(&policy->kobj, KOBJ_ADD);
974 module_put(cpufreq_driver->owner);
975 pr_debug("initialization complete\n");
976
977 return 0;
978
979
980err_out_unregister:
981 spin_lock_irqsave(&cpufreq_driver_lock, flags);
982 for_each_cpu(j, policy->cpus)
983 per_cpu(cpufreq_cpu_data, j) = NULL;
984 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
985
986 kobject_put(&policy->kobj);
987 wait_for_completion(&policy->kobj_unregister);
988
989err_unlock_policy:
990 unlock_policy_rwsem_write(cpu);
991 free_cpumask_var(policy->related_cpus);
992err_free_cpumask:
993 free_cpumask_var(policy->cpus);
994err_free_policy:
995 kfree(policy);
996nomem_out:
997 module_put(cpufreq_driver->owner);
998module_out:
999 return ret;
1000}
1001
1002
1003/**
1004 * __cpufreq_remove_dev - remove a CPU device
1005 *
1006 * Removes the cpufreq interface for a CPU device.
1007 * Caller should already have policy_rwsem in write mode for this CPU.
1008 * This routine frees the rwsem before returning.
1009 */
1010static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1011{
1012 unsigned int cpu = dev->id;
1013 unsigned long flags;
1014 struct cpufreq_policy *data;
1015 struct kobject *kobj;
1016 struct completion *cmp;
1017#ifdef CONFIG_SMP
1018 struct device *cpu_dev;
1019 unsigned int j;
1020#endif
1021
1022 pr_debug("unregistering CPU %u\n", cpu);
1023
1024 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1025 data = per_cpu(cpufreq_cpu_data, cpu);
1026
1027 if (!data) {
1028 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1029 unlock_policy_rwsem_write(cpu);
1030 return -EINVAL;
1031 }
1032 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1033
1034
1035#ifdef CONFIG_SMP
1036 /* if this isn't the CPU which is the parent of the kobj, we
1037 * only need to unlink, put and exit
1038 */
1039 if (unlikely(cpu != data->cpu)) {
1040 pr_debug("removing link\n");
1041 cpumask_clear_cpu(cpu, data->cpus);
1042 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1043 kobj = &dev->kobj;
1044 cpufreq_cpu_put(data);
1045 unlock_policy_rwsem_write(cpu);
1046 sysfs_remove_link(kobj, "cpufreq");
1047 return 0;
1048 }
1049#endif
1050
1051#ifdef CONFIG_SMP
1052
1053#ifdef CONFIG_HOTPLUG_CPU
1054 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1055 CPUFREQ_NAME_LEN);
1056#endif
1057
1058 /* if we have other CPUs still registered, we need to unlink them,
1059 * or else wait_for_completion below will lock up. Clean the
1060 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1061 * the sysfs links afterwards.
1062 */
1063 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1064 for_each_cpu(j, data->cpus) {
1065 if (j == cpu)
1066 continue;
1067 per_cpu(cpufreq_cpu_data, j) = NULL;
1068 }
1069 }
1070
1071 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1072
1073 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1074 for_each_cpu(j, data->cpus) {
1075 if (j == cpu)
1076 continue;
1077 pr_debug("removing link for cpu %u\n", j);
1078#ifdef CONFIG_HOTPLUG_CPU
1079 strncpy(per_cpu(cpufreq_cpu_governor, j),
1080 data->governor->name, CPUFREQ_NAME_LEN);
1081#endif
1082 cpu_dev = get_cpu_device(j);
1083 kobj = &cpu_dev->kobj;
1084 unlock_policy_rwsem_write(cpu);
1085 sysfs_remove_link(kobj, "cpufreq");
1086 lock_policy_rwsem_write(cpu);
1087 cpufreq_cpu_put(data);
1088 }
1089 }
1090#else
1091 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1092#endif
1093
1094 if (cpufreq_driver->target)
1095 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1096
1097 kobj = &data->kobj;
1098 cmp = &data->kobj_unregister;
1099 unlock_policy_rwsem_write(cpu);
1100 kobject_put(kobj);
1101
1102 /* we need to make sure that the underlying kobj is actually
1103 * not referenced anymore by anybody before we proceed with
1104 * unloading.
1105 */
1106 pr_debug("waiting for dropping of refcount\n");
1107 wait_for_completion(cmp);
1108 pr_debug("wait complete\n");
1109
1110 lock_policy_rwsem_write(cpu);
1111 if (cpufreq_driver->exit)
1112 cpufreq_driver->exit(data);
1113 unlock_policy_rwsem_write(cpu);
1114
1115#ifdef CONFIG_HOTPLUG_CPU
1116 /* when the CPU which is the parent of the kobj is hotplugged
1117 * offline, check for siblings, and create cpufreq sysfs interface
1118 * and symlinks
1119 */
1120 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1121 /* first sibling now owns the new sysfs dir */
1122 cpumask_clear_cpu(cpu, data->cpus);
1123 cpufreq_add_dev(get_cpu_device(cpumask_first(data->cpus)), NULL);
1124
1125 /* finally remove our own symlink */
1126 lock_policy_rwsem_write(cpu);
1127 __cpufreq_remove_dev(dev, sif);
1128 }
1129#endif
1130
1131 free_cpumask_var(data->related_cpus);
1132 free_cpumask_var(data->cpus);
1133 kfree(data);
1134
1135 return 0;
1136}
1137
1138
1139static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1140{
1141 unsigned int cpu = dev->id;
1142 int retval;
1143
1144 if (cpu_is_offline(cpu))
1145 return 0;
1146
1147 if (unlikely(lock_policy_rwsem_write(cpu)))
1148 BUG();
1149
1150 retval = __cpufreq_remove_dev(dev, sif);
1151 return retval;
1152}
1153
1154
1155static void handle_update(struct work_struct *work)
1156{
1157 struct cpufreq_policy *policy =
1158 container_of(work, struct cpufreq_policy, update);
1159 unsigned int cpu = policy->cpu;
1160 pr_debug("handle_update for cpu %u called\n", cpu);
1161 cpufreq_update_policy(cpu);
1162}
1163
1164/**
1165 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1166 * @cpu: cpu number
1167 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1168 * @new_freq: CPU frequency the CPU actually runs at
1169 *
1170 * We adjust to current frequency first, and need to clean up later.
1171 * So either call to cpufreq_update_policy() or schedule handle_update()).
1172 */
1173static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1174 unsigned int new_freq)
1175{
1176 struct cpufreq_freqs freqs;
1177
1178 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1179 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1180
1181 freqs.cpu = cpu;
1182 freqs.old = old_freq;
1183 freqs.new = new_freq;
1184 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1185 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1186}
1187
1188
1189/**
1190 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1191 * @cpu: CPU number
1192 *
1193 * This is the last known freq, without actually getting it from the driver.
1194 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1195 */
1196unsigned int cpufreq_quick_get(unsigned int cpu)
1197{
1198 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1199 unsigned int ret_freq = 0;
1200
1201 if (policy) {
1202 ret_freq = policy->cur;
1203 cpufreq_cpu_put(policy);
1204 }
1205
1206 return ret_freq;
1207}
1208EXPORT_SYMBOL(cpufreq_quick_get);
1209
1210/**
1211 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1212 * @cpu: CPU number
1213 *
1214 * Just return the max possible frequency for a given CPU.
1215 */
1216unsigned int cpufreq_quick_get_max(unsigned int cpu)
1217{
1218 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1219 unsigned int ret_freq = 0;
1220
1221 if (policy) {
1222 ret_freq = policy->max;
1223 cpufreq_cpu_put(policy);
1224 }
1225
1226 return ret_freq;
1227}
1228EXPORT_SYMBOL(cpufreq_quick_get_max);
1229
1230
1231static unsigned int __cpufreq_get(unsigned int cpu)
1232{
1233 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1234 unsigned int ret_freq = 0;
1235
1236 if (!cpufreq_driver->get)
1237 return ret_freq;
1238
1239 ret_freq = cpufreq_driver->get(cpu);
1240
1241 if (ret_freq && policy->cur &&
1242 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1243 /* verify no discrepancy between actual and
1244 saved value exists */
1245 if (unlikely(ret_freq != policy->cur)) {
1246 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1247 schedule_work(&policy->update);
1248 }
1249 }
1250
1251 return ret_freq;
1252}
1253
1254/**
1255 * cpufreq_get - get the current CPU frequency (in kHz)
1256 * @cpu: CPU number
1257 *
1258 * Get the CPU current (static) CPU frequency
1259 */
1260unsigned int cpufreq_get(unsigned int cpu)
1261{
1262 unsigned int ret_freq = 0;
1263 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1264
1265 if (!policy)
1266 goto out;
1267
1268 if (unlikely(lock_policy_rwsem_read(cpu)))
1269 goto out_policy;
1270
1271 ret_freq = __cpufreq_get(cpu);
1272
1273 unlock_policy_rwsem_read(cpu);
1274
1275out_policy:
1276 cpufreq_cpu_put(policy);
1277out:
1278 return ret_freq;
1279}
1280EXPORT_SYMBOL(cpufreq_get);
1281
1282static struct subsys_interface cpufreq_interface = {
1283 .name = "cpufreq",
1284 .subsys = &cpu_subsys,
1285 .add_dev = cpufreq_add_dev,
1286 .remove_dev = cpufreq_remove_dev,
1287};
1288
1289
1290/**
1291 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1292 *
1293 * This function is only executed for the boot processor. The other CPUs
1294 * have been put offline by means of CPU hotplug.
1295 */
1296static int cpufreq_bp_suspend(void)
1297{
1298 int ret = 0;
1299
1300 int cpu = smp_processor_id();
1301 struct cpufreq_policy *cpu_policy;
1302
1303 pr_debug("suspending cpu %u\n", cpu);
1304
1305 /* If there's no policy for the boot CPU, we have nothing to do. */
1306 cpu_policy = cpufreq_cpu_get(cpu);
1307 if (!cpu_policy)
1308 return 0;
1309
1310 if (cpufreq_driver->suspend) {
1311 ret = cpufreq_driver->suspend(cpu_policy);
1312 if (ret)
1313 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1314 "step on CPU %u\n", cpu_policy->cpu);
1315 }
1316
1317 cpufreq_cpu_put(cpu_policy);
1318 return ret;
1319}
1320
1321/**
1322 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1323 *
1324 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1325 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1326 * restored. It will verify that the current freq is in sync with
1327 * what we believe it to be. This is a bit later than when it
1328 * should be, but nonethteless it's better than calling
1329 * cpufreq_driver->get() here which might re-enable interrupts...
1330 *
1331 * This function is only executed for the boot CPU. The other CPUs have not
1332 * been turned on yet.
1333 */
1334static void cpufreq_bp_resume(void)
1335{
1336 int ret = 0;
1337
1338 int cpu = smp_processor_id();
1339 struct cpufreq_policy *cpu_policy;
1340
1341 pr_debug("resuming cpu %u\n", cpu);
1342
1343 /* If there's no policy for the boot CPU, we have nothing to do. */
1344 cpu_policy = cpufreq_cpu_get(cpu);
1345 if (!cpu_policy)
1346 return;
1347
1348 if (cpufreq_driver->resume) {
1349 ret = cpufreq_driver->resume(cpu_policy);
1350 if (ret) {
1351 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1352 "step on CPU %u\n", cpu_policy->cpu);
1353 goto fail;
1354 }
1355 }
1356
1357 schedule_work(&cpu_policy->update);
1358
1359fail:
1360 cpufreq_cpu_put(cpu_policy);
1361}
1362
1363static struct syscore_ops cpufreq_syscore_ops = {
1364 .suspend = cpufreq_bp_suspend,
1365 .resume = cpufreq_bp_resume,
1366};
1367
1368
1369/*********************************************************************
1370 * NOTIFIER LISTS INTERFACE *
1371 *********************************************************************/
1372
1373/**
1374 * cpufreq_register_notifier - register a driver with cpufreq
1375 * @nb: notifier function to register
1376 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1377 *
1378 * Add a driver to one of two lists: either a list of drivers that
1379 * are notified about clock rate changes (once before and once after
1380 * the transition), or a list of drivers that are notified about
1381 * changes in cpufreq policy.
1382 *
1383 * This function may sleep, and has the same return conditions as
1384 * blocking_notifier_chain_register.
1385 */
1386int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1387{
1388 int ret;
1389
1390 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1391
1392 switch (list) {
1393 case CPUFREQ_TRANSITION_NOTIFIER:
1394 ret = srcu_notifier_chain_register(
1395 &cpufreq_transition_notifier_list, nb);
1396 break;
1397 case CPUFREQ_POLICY_NOTIFIER:
1398 ret = blocking_notifier_chain_register(
1399 &cpufreq_policy_notifier_list, nb);
1400 break;
1401 default:
1402 ret = -EINVAL;
1403 }
1404
1405 return ret;
1406}
1407EXPORT_SYMBOL(cpufreq_register_notifier);
1408
1409
1410/**
1411 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1412 * @nb: notifier block to be unregistered
1413 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1414 *
1415 * Remove a driver from the CPU frequency notifier list.
1416 *
1417 * This function may sleep, and has the same return conditions as
1418 * blocking_notifier_chain_unregister.
1419 */
1420int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1421{
1422 int ret;
1423
1424 switch (list) {
1425 case CPUFREQ_TRANSITION_NOTIFIER:
1426 ret = srcu_notifier_chain_unregister(
1427 &cpufreq_transition_notifier_list, nb);
1428 break;
1429 case CPUFREQ_POLICY_NOTIFIER:
1430 ret = blocking_notifier_chain_unregister(
1431 &cpufreq_policy_notifier_list, nb);
1432 break;
1433 default:
1434 ret = -EINVAL;
1435 }
1436
1437 return ret;
1438}
1439EXPORT_SYMBOL(cpufreq_unregister_notifier);
1440
1441
1442/*********************************************************************
1443 * GOVERNORS *
1444 *********************************************************************/
1445
1446
1447int __cpufreq_driver_target(struct cpufreq_policy *policy,
1448 unsigned int target_freq,
1449 unsigned int relation)
1450{
1451 int retval = -EINVAL;
1452
1453 if (cpufreq_disabled())
1454 return -ENODEV;
1455
1456 pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1457 target_freq, relation);
1458 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1459 retval = cpufreq_driver->target(policy, target_freq, relation);
1460
1461 return retval;
1462}
1463EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1464
1465int cpufreq_driver_target(struct cpufreq_policy *policy,
1466 unsigned int target_freq,
1467 unsigned int relation)
1468{
1469 int ret = -EINVAL;
1470
1471 policy = cpufreq_cpu_get(policy->cpu);
1472 if (!policy)
1473 goto no_policy;
1474
1475 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1476 goto fail;
1477
1478 ret = __cpufreq_driver_target(policy, target_freq, relation);
1479
1480 unlock_policy_rwsem_write(policy->cpu);
1481
1482fail:
1483 cpufreq_cpu_put(policy);
1484no_policy:
1485 return ret;
1486}
1487EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1488
1489int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1490{
1491 int ret = 0;
1492
1493 policy = cpufreq_cpu_get(policy->cpu);
1494 if (!policy)
1495 return -EINVAL;
1496
1497 if (cpu_online(cpu) && cpufreq_driver->getavg)
1498 ret = cpufreq_driver->getavg(policy, cpu);
1499
1500 cpufreq_cpu_put(policy);
1501 return ret;
1502}
1503EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1504
1505/*
1506 * when "event" is CPUFREQ_GOV_LIMITS
1507 */
1508
1509static int __cpufreq_governor(struct cpufreq_policy *policy,
1510 unsigned int event)
1511{
1512 int ret;
1513
1514 /* Only must be defined when default governor is known to have latency
1515 restrictions, like e.g. conservative or ondemand.
1516 That this is the case is already ensured in Kconfig
1517 */
1518#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1519 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1520#else
1521 struct cpufreq_governor *gov = NULL;
1522#endif
1523
1524 if (policy->governor->max_transition_latency &&
1525 policy->cpuinfo.transition_latency >
1526 policy->governor->max_transition_latency) {
1527 if (!gov)
1528 return -EINVAL;
1529 else {
1530 printk(KERN_WARNING "%s governor failed, too long"
1531 " transition latency of HW, fallback"
1532 " to %s governor\n",
1533 policy->governor->name,
1534 gov->name);
1535 policy->governor = gov;
1536 }
1537 }
1538
1539 if (!try_module_get(policy->governor->owner))
1540 return -EINVAL;
1541
1542 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1543 policy->cpu, event);
1544 ret = policy->governor->governor(policy, event);
1545
1546 /* we keep one module reference alive for
1547 each CPU governed by this CPU */
1548 if ((event != CPUFREQ_GOV_START) || ret)
1549 module_put(policy->governor->owner);
1550 if ((event == CPUFREQ_GOV_STOP) && !ret)
1551 module_put(policy->governor->owner);
1552
1553 return ret;
1554}
1555
1556
1557int cpufreq_register_governor(struct cpufreq_governor *governor)
1558{
1559 int err;
1560
1561 if (!governor)
1562 return -EINVAL;
1563
1564 if (cpufreq_disabled())
1565 return -ENODEV;
1566
1567 mutex_lock(&cpufreq_governor_mutex);
1568
1569 err = -EBUSY;
1570 if (__find_governor(governor->name) == NULL) {
1571 err = 0;
1572 list_add(&governor->governor_list, &cpufreq_governor_list);
1573 }
1574
1575 mutex_unlock(&cpufreq_governor_mutex);
1576 return err;
1577}
1578EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1579
1580
1581void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1582{
1583#ifdef CONFIG_HOTPLUG_CPU
1584 int cpu;
1585#endif
1586
1587 if (!governor)
1588 return;
1589
1590 if (cpufreq_disabled())
1591 return;
1592
1593#ifdef CONFIG_HOTPLUG_CPU
1594 for_each_present_cpu(cpu) {
1595 if (cpu_online(cpu))
1596 continue;
1597 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1598 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1599 }
1600#endif
1601
1602 mutex_lock(&cpufreq_governor_mutex);
1603 list_del(&governor->governor_list);
1604 mutex_unlock(&cpufreq_governor_mutex);
1605 return;
1606}
1607EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1608
1609
1610
1611/*********************************************************************
1612 * POLICY INTERFACE *
1613 *********************************************************************/
1614
1615/**
1616 * cpufreq_get_policy - get the current cpufreq_policy
1617 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1618 * is written
1619 *
1620 * Reads the current cpufreq policy.
1621 */
1622int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1623{
1624 struct cpufreq_policy *cpu_policy;
1625 if (!policy)
1626 return -EINVAL;
1627
1628 cpu_policy = cpufreq_cpu_get(cpu);
1629 if (!cpu_policy)
1630 return -EINVAL;
1631
1632 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1633
1634 cpufreq_cpu_put(cpu_policy);
1635 return 0;
1636}
1637EXPORT_SYMBOL(cpufreq_get_policy);
1638
1639
1640/*
1641 * data : current policy.
1642 * policy : policy to be set.
1643 */
1644static int __cpufreq_set_policy(struct cpufreq_policy *data,
1645 struct cpufreq_policy *policy)
1646{
1647 int ret = 0;
1648
1649 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1650 policy->min, policy->max);
1651
1652 memcpy(&policy->cpuinfo, &data->cpuinfo,
1653 sizeof(struct cpufreq_cpuinfo));
1654
1655 if (policy->min > data->max || policy->max < data->min) {
1656 ret = -EINVAL;
1657 goto error_out;
1658 }
1659
1660 /* verify the cpu speed can be set within this limit */
1661 ret = cpufreq_driver->verify(policy);
1662 if (ret)
1663 goto error_out;
1664
1665 /* adjust if necessary - all reasons */
1666 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1667 CPUFREQ_ADJUST, policy);
1668
1669 /* adjust if necessary - hardware incompatibility*/
1670 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1671 CPUFREQ_INCOMPATIBLE, policy);
1672
1673 /* verify the cpu speed can be set within this limit,
1674 which might be different to the first one */
1675 ret = cpufreq_driver->verify(policy);
1676 if (ret)
1677 goto error_out;
1678
1679 /* notification of the new policy */
1680 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1681 CPUFREQ_NOTIFY, policy);
1682
1683 data->min = policy->min;
1684 data->max = policy->max;
1685
1686 pr_debug("new min and max freqs are %u - %u kHz\n",
1687 data->min, data->max);
1688
1689 if (cpufreq_driver->setpolicy) {
1690 data->policy = policy->policy;
1691 pr_debug("setting range\n");
1692 ret = cpufreq_driver->setpolicy(policy);
1693 } else {
1694 if (policy->governor != data->governor) {
1695 /* save old, working values */
1696 struct cpufreq_governor *old_gov = data->governor;
1697
1698 pr_debug("governor switch\n");
1699
1700 /* end old governor */
1701 if (data->governor)
1702 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1703
1704 /* start new governor */
1705 data->governor = policy->governor;
1706 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1707 /* new governor failed, so re-start old one */
1708 pr_debug("starting governor %s failed\n",
1709 data->governor->name);
1710 if (old_gov) {
1711 data->governor = old_gov;
1712 __cpufreq_governor(data,
1713 CPUFREQ_GOV_START);
1714 }
1715 ret = -EINVAL;
1716 goto error_out;
1717 }
1718 /* might be a policy change, too, so fall through */
1719 }
1720 pr_debug("governor: change or update limits\n");
1721 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1722 }
1723
1724error_out:
1725 return ret;
1726}
1727
1728/**
1729 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1730 * @cpu: CPU which shall be re-evaluated
1731 *
1732 * Useful for policy notifiers which have different necessities
1733 * at different times.
1734 */
1735int cpufreq_update_policy(unsigned int cpu)
1736{
1737 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1738 struct cpufreq_policy policy;
1739 int ret;
1740
1741 if (!data) {
1742 ret = -ENODEV;
1743 goto no_policy;
1744 }
1745
1746 if (unlikely(lock_policy_rwsem_write(cpu))) {
1747 ret = -EINVAL;
1748 goto fail;
1749 }
1750
1751 pr_debug("updating policy for CPU %u\n", cpu);
1752 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1753 policy.min = data->user_policy.min;
1754 policy.max = data->user_policy.max;
1755 policy.policy = data->user_policy.policy;
1756 policy.governor = data->user_policy.governor;
1757
1758 /* BIOS might change freq behind our back
1759 -> ask driver for current freq and notify governors about a change */
1760 if (cpufreq_driver->get) {
1761 policy.cur = cpufreq_driver->get(cpu);
1762 if (!data->cur) {
1763 pr_debug("Driver did not initialize current freq");
1764 data->cur = policy.cur;
1765 } else {
1766 if (data->cur != policy.cur)
1767 cpufreq_out_of_sync(cpu, data->cur,
1768 policy.cur);
1769 }
1770 }
1771
1772 ret = __cpufreq_set_policy(data, &policy);
1773
1774 unlock_policy_rwsem_write(cpu);
1775
1776fail:
1777 cpufreq_cpu_put(data);
1778no_policy:
1779 return ret;
1780}
1781EXPORT_SYMBOL(cpufreq_update_policy);
1782
1783static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1784 unsigned long action, void *hcpu)
1785{
1786 unsigned int cpu = (unsigned long)hcpu;
1787 struct device *dev;
1788
1789 dev = get_cpu_device(cpu);
1790 if (dev) {
1791 switch (action) {
1792 case CPU_ONLINE:
1793 case CPU_ONLINE_FROZEN:
1794 cpufreq_add_dev(dev, NULL);
1795 break;
1796 case CPU_DOWN_PREPARE:
1797 case CPU_DOWN_PREPARE_FROZEN:
1798 if (unlikely(lock_policy_rwsem_write(cpu)))
1799 BUG();
1800
1801 __cpufreq_remove_dev(dev, NULL);
1802 break;
1803 case CPU_DOWN_FAILED:
1804 case CPU_DOWN_FAILED_FROZEN:
1805 cpufreq_add_dev(dev, NULL);
1806 break;
1807 }
1808 }
1809 return NOTIFY_OK;
1810}
1811
1812static struct notifier_block __refdata cpufreq_cpu_notifier = {
1813 .notifier_call = cpufreq_cpu_callback,
1814};
1815
1816/*********************************************************************
1817 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1818 *********************************************************************/
1819
1820/**
1821 * cpufreq_register_driver - register a CPU Frequency driver
1822 * @driver_data: A struct cpufreq_driver containing the values#
1823 * submitted by the CPU Frequency driver.
1824 *
1825 * Registers a CPU Frequency driver to this core code. This code
1826 * returns zero on success, -EBUSY when another driver got here first
1827 * (and isn't unregistered in the meantime).
1828 *
1829 */
1830int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1831{
1832 unsigned long flags;
1833 int ret;
1834
1835 if (cpufreq_disabled())
1836 return -ENODEV;
1837
1838 if (!driver_data || !driver_data->verify || !driver_data->init ||
1839 ((!driver_data->setpolicy) && (!driver_data->target)))
1840 return -EINVAL;
1841
1842 pr_debug("trying to register driver %s\n", driver_data->name);
1843
1844 if (driver_data->setpolicy)
1845 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1846
1847 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1848 if (cpufreq_driver) {
1849 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1850 return -EBUSY;
1851 }
1852 cpufreq_driver = driver_data;
1853 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1854
1855 ret = subsys_interface_register(&cpufreq_interface);
1856 if (ret)
1857 goto err_null_driver;
1858
1859 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1860 int i;
1861 ret = -ENODEV;
1862
1863 /* check for at least one working CPU */
1864 for (i = 0; i < nr_cpu_ids; i++)
1865 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1866 ret = 0;
1867 break;
1868 }
1869
1870 /* if all ->init() calls failed, unregister */
1871 if (ret) {
1872 pr_debug("no CPU initialized for driver %s\n",
1873 driver_data->name);
1874 goto err_if_unreg;
1875 }
1876 }
1877
1878 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1879 pr_debug("driver %s up and running\n", driver_data->name);
1880
1881 return 0;
1882err_if_unreg:
1883 subsys_interface_unregister(&cpufreq_interface);
1884err_null_driver:
1885 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1886 cpufreq_driver = NULL;
1887 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1888 return ret;
1889}
1890EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1891
1892
1893/**
1894 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1895 *
1896 * Unregister the current CPUFreq driver. Only call this if you have
1897 * the right to do so, i.e. if you have succeeded in initialising before!
1898 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1899 * currently not initialised.
1900 */
1901int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1902{
1903 unsigned long flags;
1904
1905 if (!cpufreq_driver || (driver != cpufreq_driver))
1906 return -EINVAL;
1907
1908 pr_debug("unregistering driver %s\n", driver->name);
1909
1910 subsys_interface_unregister(&cpufreq_interface);
1911 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1912
1913 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1914 cpufreq_driver = NULL;
1915 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1916
1917 return 0;
1918}
1919EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1920
1921static int __init cpufreq_core_init(void)
1922{
1923 int cpu;
1924
1925 if (cpufreq_disabled())
1926 return -ENODEV;
1927
1928 for_each_possible_cpu(cpu) {
1929 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1930 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1931 }
1932
1933 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
1934 BUG_ON(!cpufreq_global_kobject);
1935 register_syscore_ops(&cpufreq_syscore_ops);
1936
1937 return 0;
1938}
1939core_initcall(cpufreq_core_init);