2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
34 static LIST_HEAD(cpufreq_policy_list);
36 static inline bool policy_is_inactive(struct cpufreq_policy *policy)
38 return cpumask_empty(policy->cpus);
41 static bool suitable_policy(struct cpufreq_policy *policy, bool active)
43 return active == !policy_is_inactive(policy);
46 /* Finds Next Acive/Inactive policy */
47 static struct cpufreq_policy *next_policy(struct cpufreq_policy *policy,
51 policy = list_next_entry(policy, policy_list);
53 /* No more policies in the list */
54 if (&policy->policy_list == &cpufreq_policy_list)
56 } while (!suitable_policy(policy, active));
61 static struct cpufreq_policy *first_policy(bool active)
63 struct cpufreq_policy *policy;
65 /* No policies in the list */
66 if (list_empty(&cpufreq_policy_list))
69 policy = list_first_entry(&cpufreq_policy_list, typeof(*policy),
72 if (!suitable_policy(policy, active))
73 policy = next_policy(policy, active);
78 /* Macros to iterate over CPU policies */
79 #define for_each_suitable_policy(__policy, __active) \
80 for (__policy = first_policy(__active); \
82 __policy = next_policy(__policy, __active))
84 #define for_each_active_policy(__policy) \
85 for_each_suitable_policy(__policy, true)
86 #define for_each_inactive_policy(__policy) \
87 for_each_suitable_policy(__policy, false)
89 #define for_each_policy(__policy) \
90 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
92 /* Iterate over governors */
93 static LIST_HEAD(cpufreq_governor_list);
94 #define for_each_governor(__governor) \
95 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
98 * The "cpufreq driver" - the arch- or hardware-dependent low
99 * level driver of CPUFreq support, and its spinlock. This lock
100 * also protects the cpufreq_cpu_data array.
102 static struct cpufreq_driver *cpufreq_driver;
103 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
104 static DEFINE_RWLOCK(cpufreq_driver_lock);
105 DEFINE_MUTEX(cpufreq_governor_lock);
107 /* Flag to suspend/resume CPUFreq governors */
108 static bool cpufreq_suspended;
110 static inline bool has_target(void)
112 return cpufreq_driver->target_index || cpufreq_driver->target;
115 /* internal prototypes */
116 static int __cpufreq_governor(struct cpufreq_policy *policy,
118 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
119 static void handle_update(struct work_struct *work);
122 * Two notifier lists: the "policy" list is involved in the
123 * validation process for a new CPU frequency policy; the
124 * "transition" list for kernel code that needs to handle
125 * changes to devices when the CPU clock speed changes.
126 * The mutex locks both lists.
128 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
129 static struct srcu_notifier_head cpufreq_transition_notifier_list;
131 static bool init_cpufreq_transition_notifier_list_called;
132 static int __init init_cpufreq_transition_notifier_list(void)
134 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
135 init_cpufreq_transition_notifier_list_called = true;
138 pure_initcall(init_cpufreq_transition_notifier_list);
140 static int off __read_mostly;
141 static int cpufreq_disabled(void)
145 void disable_cpufreq(void)
149 static DEFINE_MUTEX(cpufreq_governor_mutex);
151 bool have_governor_per_policy(void)
153 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
155 EXPORT_SYMBOL_GPL(have_governor_per_policy);
157 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
159 if (have_governor_per_policy())
160 return &policy->kobj;
162 return cpufreq_global_kobject;
164 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
166 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
168 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
170 return policy && !policy_is_inactive(policy) ?
171 policy->freq_table : NULL;
173 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
175 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
181 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
183 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
184 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
185 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
186 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
187 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
188 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
190 idle_time = cur_wall_time - busy_time;
192 *wall = cputime_to_usecs(cur_wall_time);
194 return cputime_to_usecs(idle_time);
197 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
199 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
201 if (idle_time == -1ULL)
202 return get_cpu_idle_time_jiffy(cpu, wall);
204 idle_time += get_cpu_iowait_time_us(cpu, wall);
208 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
211 * This is a generic cpufreq init() routine which can be used by cpufreq
212 * drivers of SMP systems. It will do following:
213 * - validate & show freq table passed
214 * - set policies transition latency
215 * - policy->cpus with all possible CPUs
217 int cpufreq_generic_init(struct cpufreq_policy *policy,
218 struct cpufreq_frequency_table *table,
219 unsigned int transition_latency)
223 ret = cpufreq_table_validate_and_show(policy, table);
225 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
229 policy->cpuinfo.transition_latency = transition_latency;
232 * The driver only supports the SMP configuration where all processors
233 * share the clock and voltage and clock.
235 cpumask_setall(policy->cpus);
239 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
241 /* Only for cpufreq core internal use */
242 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
244 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
246 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
249 unsigned int cpufreq_generic_get(unsigned int cpu)
251 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
253 if (!policy || IS_ERR(policy->clk)) {
254 pr_err("%s: No %s associated to cpu: %d\n",
255 __func__, policy ? "clk" : "policy", cpu);
259 return clk_get_rate(policy->clk) / 1000;
261 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
264 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
266 * @cpu: cpu to find policy for.
268 * This returns policy for 'cpu', returns NULL if it doesn't exist.
269 * It also increments the kobject reference count to mark it busy and so would
270 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
271 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
272 * freed as that depends on the kobj count.
274 * Return: A valid policy on success, otherwise NULL on failure.
276 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
278 struct cpufreq_policy *policy = NULL;
281 if (WARN_ON(cpu >= nr_cpu_ids))
284 /* get the cpufreq driver */
285 read_lock_irqsave(&cpufreq_driver_lock, flags);
287 if (cpufreq_driver) {
289 policy = cpufreq_cpu_get_raw(cpu);
291 kobject_get(&policy->kobj);
294 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
298 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
301 * cpufreq_cpu_put: Decrements the usage count of a policy
303 * @policy: policy earlier returned by cpufreq_cpu_get().
305 * This decrements the kobject reference count incremented earlier by calling
308 void cpufreq_cpu_put(struct cpufreq_policy *policy)
310 kobject_put(&policy->kobj);
312 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
314 /*********************************************************************
315 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
316 *********************************************************************/
319 * adjust_jiffies - adjust the system "loops_per_jiffy"
321 * This function alters the system "loops_per_jiffy" for the clock
322 * speed change. Note that loops_per_jiffy cannot be updated on SMP
323 * systems as each CPU might be scaled differently. So, use the arch
324 * per-CPU loops_per_jiffy value wherever possible.
326 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
329 static unsigned long l_p_j_ref;
330 static unsigned int l_p_j_ref_freq;
332 if (ci->flags & CPUFREQ_CONST_LOOPS)
335 if (!l_p_j_ref_freq) {
336 l_p_j_ref = loops_per_jiffy;
337 l_p_j_ref_freq = ci->old;
338 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
339 l_p_j_ref, l_p_j_ref_freq);
341 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
342 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
344 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
345 loops_per_jiffy, ci->new);
350 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
351 struct cpufreq_freqs *freqs, unsigned int state)
353 BUG_ON(irqs_disabled());
355 if (cpufreq_disabled())
358 freqs->flags = cpufreq_driver->flags;
359 pr_debug("notification %u of frequency transition to %u kHz\n",
364 case CPUFREQ_PRECHANGE:
365 /* detect if the driver reported a value as "old frequency"
366 * which is not equal to what the cpufreq core thinks is
369 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
370 if ((policy) && (policy->cpu == freqs->cpu) &&
371 (policy->cur) && (policy->cur != freqs->old)) {
372 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
373 freqs->old, policy->cur);
374 freqs->old = policy->cur;
377 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
378 CPUFREQ_PRECHANGE, freqs);
379 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
382 case CPUFREQ_POSTCHANGE:
383 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
384 pr_debug("FREQ: %lu - CPU: %lu\n",
385 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
386 trace_cpu_frequency(freqs->new, freqs->cpu);
387 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
388 CPUFREQ_POSTCHANGE, freqs);
389 if (likely(policy) && likely(policy->cpu == freqs->cpu))
390 policy->cur = freqs->new;
396 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
397 * on frequency transition.
399 * This function calls the transition notifiers and the "adjust_jiffies"
400 * function. It is called twice on all CPU frequency changes that have
403 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
404 struct cpufreq_freqs *freqs, unsigned int state)
406 for_each_cpu(freqs->cpu, policy->cpus)
407 __cpufreq_notify_transition(policy, freqs, state);
410 /* Do post notifications when there are chances that transition has failed */
411 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
412 struct cpufreq_freqs *freqs, int transition_failed)
414 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
415 if (!transition_failed)
418 swap(freqs->old, freqs->new);
419 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
420 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
423 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
424 struct cpufreq_freqs *freqs)
428 * Catch double invocations of _begin() which lead to self-deadlock.
429 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
430 * doesn't invoke _begin() on their behalf, and hence the chances of
431 * double invocations are very low. Moreover, there are scenarios
432 * where these checks can emit false-positive warnings in these
433 * drivers; so we avoid that by skipping them altogether.
435 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
436 && current == policy->transition_task);
439 wait_event(policy->transition_wait, !policy->transition_ongoing);
441 spin_lock(&policy->transition_lock);
443 if (unlikely(policy->transition_ongoing)) {
444 spin_unlock(&policy->transition_lock);
448 policy->transition_ongoing = true;
449 policy->transition_task = current;
451 spin_unlock(&policy->transition_lock);
453 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
455 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
457 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
458 struct cpufreq_freqs *freqs, int transition_failed)
460 if (unlikely(WARN_ON(!policy->transition_ongoing)))
463 cpufreq_notify_post_transition(policy, freqs, transition_failed);
465 policy->transition_ongoing = false;
466 policy->transition_task = NULL;
468 wake_up(&policy->transition_wait);
470 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
473 /*********************************************************************
475 *********************************************************************/
476 static ssize_t show_boost(struct kobject *kobj,
477 struct attribute *attr, char *buf)
479 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
482 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
483 const char *buf, size_t count)
487 ret = sscanf(buf, "%d", &enable);
488 if (ret != 1 || enable < 0 || enable > 1)
491 if (cpufreq_boost_trigger_state(enable)) {
492 pr_err("%s: Cannot %s BOOST!\n",
493 __func__, enable ? "enable" : "disable");
497 pr_debug("%s: cpufreq BOOST %s\n",
498 __func__, enable ? "enabled" : "disabled");
502 define_one_global_rw(boost);
504 static struct cpufreq_governor *find_governor(const char *str_governor)
506 struct cpufreq_governor *t;
509 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
516 * cpufreq_parse_governor - parse a governor string
518 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
519 struct cpufreq_governor **governor)
526 if (cpufreq_driver->setpolicy) {
527 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
528 *policy = CPUFREQ_POLICY_PERFORMANCE;
530 } else if (!strncasecmp(str_governor, "powersave",
532 *policy = CPUFREQ_POLICY_POWERSAVE;
536 struct cpufreq_governor *t;
538 mutex_lock(&cpufreq_governor_mutex);
540 t = find_governor(str_governor);
545 mutex_unlock(&cpufreq_governor_mutex);
546 ret = request_module("cpufreq_%s", str_governor);
547 mutex_lock(&cpufreq_governor_mutex);
550 t = find_governor(str_governor);
558 mutex_unlock(&cpufreq_governor_mutex);
565 * cpufreq_per_cpu_attr_read() / show_##file_name() -
566 * print out cpufreq information
568 * Write out information from cpufreq_driver->policy[cpu]; object must be
572 #define show_one(file_name, object) \
573 static ssize_t show_##file_name \
574 (struct cpufreq_policy *policy, char *buf) \
576 return sprintf(buf, "%u\n", policy->object); \
579 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
580 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
581 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
582 show_one(scaling_min_freq, min);
583 show_one(scaling_max_freq, max);
585 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
589 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
590 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
592 ret = sprintf(buf, "%u\n", policy->cur);
596 static int cpufreq_set_policy(struct cpufreq_policy *policy,
597 struct cpufreq_policy *new_policy);
600 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
602 #define store_one(file_name, object) \
603 static ssize_t store_##file_name \
604 (struct cpufreq_policy *policy, const char *buf, size_t count) \
607 struct cpufreq_policy new_policy; \
609 memcpy(&new_policy, policy, sizeof(*policy)); \
611 ret = sscanf(buf, "%u", &new_policy.object); \
615 temp = new_policy.object; \
616 ret = cpufreq_set_policy(policy, &new_policy); \
618 policy->user_policy.object = temp; \
620 return ret ? ret : count; \
623 store_one(scaling_min_freq, min);
624 store_one(scaling_max_freq, max);
627 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
629 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
632 unsigned int cur_freq = __cpufreq_get(policy);
634 return sprintf(buf, "<unknown>");
635 return sprintf(buf, "%u\n", cur_freq);
639 * show_scaling_governor - show the current policy for the specified CPU
641 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
643 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
644 return sprintf(buf, "powersave\n");
645 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
646 return sprintf(buf, "performance\n");
647 else if (policy->governor)
648 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
649 policy->governor->name);
654 * store_scaling_governor - store policy for the specified CPU
656 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
657 const char *buf, size_t count)
660 char str_governor[16];
661 struct cpufreq_policy new_policy;
663 memcpy(&new_policy, policy, sizeof(*policy));
665 ret = sscanf(buf, "%15s", str_governor);
669 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
670 &new_policy.governor))
673 ret = cpufreq_set_policy(policy, &new_policy);
674 return ret ? ret : count;
678 * show_scaling_driver - show the cpufreq driver currently loaded
680 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
682 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
686 * show_scaling_available_governors - show the available CPUfreq governors
688 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
692 struct cpufreq_governor *t;
695 i += sprintf(buf, "performance powersave");
699 for_each_governor(t) {
700 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
701 - (CPUFREQ_NAME_LEN + 2)))
703 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
706 i += sprintf(&buf[i], "\n");
710 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
715 for_each_cpu(cpu, mask) {
717 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
718 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
719 if (i >= (PAGE_SIZE - 5))
722 i += sprintf(&buf[i], "\n");
725 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
728 * show_related_cpus - show the CPUs affected by each transition even if
729 * hw coordination is in use
731 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
733 return cpufreq_show_cpus(policy->related_cpus, buf);
737 * show_affected_cpus - show the CPUs affected by each transition
739 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
741 return cpufreq_show_cpus(policy->cpus, buf);
744 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
745 const char *buf, size_t count)
747 unsigned int freq = 0;
750 if (!policy->governor || !policy->governor->store_setspeed)
753 ret = sscanf(buf, "%u", &freq);
757 policy->governor->store_setspeed(policy, freq);
762 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
764 if (!policy->governor || !policy->governor->show_setspeed)
765 return sprintf(buf, "<unsupported>\n");
767 return policy->governor->show_setspeed(policy, buf);
771 * show_bios_limit - show the current cpufreq HW/BIOS limitation
773 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
777 if (cpufreq_driver->bios_limit) {
778 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
780 return sprintf(buf, "%u\n", limit);
782 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
785 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
786 cpufreq_freq_attr_ro(cpuinfo_min_freq);
787 cpufreq_freq_attr_ro(cpuinfo_max_freq);
788 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
789 cpufreq_freq_attr_ro(scaling_available_governors);
790 cpufreq_freq_attr_ro(scaling_driver);
791 cpufreq_freq_attr_ro(scaling_cur_freq);
792 cpufreq_freq_attr_ro(bios_limit);
793 cpufreq_freq_attr_ro(related_cpus);
794 cpufreq_freq_attr_ro(affected_cpus);
795 cpufreq_freq_attr_rw(scaling_min_freq);
796 cpufreq_freq_attr_rw(scaling_max_freq);
797 cpufreq_freq_attr_rw(scaling_governor);
798 cpufreq_freq_attr_rw(scaling_setspeed);
800 static struct attribute *default_attrs[] = {
801 &cpuinfo_min_freq.attr,
802 &cpuinfo_max_freq.attr,
803 &cpuinfo_transition_latency.attr,
804 &scaling_min_freq.attr,
805 &scaling_max_freq.attr,
808 &scaling_governor.attr,
809 &scaling_driver.attr,
810 &scaling_available_governors.attr,
811 &scaling_setspeed.attr,
815 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
816 #define to_attr(a) container_of(a, struct freq_attr, attr)
818 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
820 struct cpufreq_policy *policy = to_policy(kobj);
821 struct freq_attr *fattr = to_attr(attr);
824 down_read(&policy->rwsem);
827 ret = fattr->show(policy, buf);
831 up_read(&policy->rwsem);
836 static ssize_t store(struct kobject *kobj, struct attribute *attr,
837 const char *buf, size_t count)
839 struct cpufreq_policy *policy = to_policy(kobj);
840 struct freq_attr *fattr = to_attr(attr);
841 ssize_t ret = -EINVAL;
845 if (!cpu_online(policy->cpu))
848 down_write(&policy->rwsem);
850 /* Updating inactive policies is invalid, so avoid doing that. */
851 if (unlikely(policy_is_inactive(policy))) {
853 goto unlock_policy_rwsem;
857 ret = fattr->store(policy, buf, count);
862 up_write(&policy->rwsem);
869 static void cpufreq_sysfs_release(struct kobject *kobj)
871 struct cpufreq_policy *policy = to_policy(kobj);
872 pr_debug("last reference is dropped\n");
873 complete(&policy->kobj_unregister);
876 static const struct sysfs_ops sysfs_ops = {
881 static struct kobj_type ktype_cpufreq = {
882 .sysfs_ops = &sysfs_ops,
883 .default_attrs = default_attrs,
884 .release = cpufreq_sysfs_release,
887 struct kobject *cpufreq_global_kobject;
888 EXPORT_SYMBOL(cpufreq_global_kobject);
890 static int cpufreq_global_kobject_usage;
892 int cpufreq_get_global_kobject(void)
894 if (!cpufreq_global_kobject_usage++)
895 return kobject_add(cpufreq_global_kobject,
896 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
900 EXPORT_SYMBOL(cpufreq_get_global_kobject);
902 void cpufreq_put_global_kobject(void)
904 if (!--cpufreq_global_kobject_usage)
905 kobject_del(cpufreq_global_kobject);
907 EXPORT_SYMBOL(cpufreq_put_global_kobject);
909 int cpufreq_sysfs_create_file(const struct attribute *attr)
911 int ret = cpufreq_get_global_kobject();
914 ret = sysfs_create_file(cpufreq_global_kobject, attr);
916 cpufreq_put_global_kobject();
921 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
923 void cpufreq_sysfs_remove_file(const struct attribute *attr)
925 sysfs_remove_file(cpufreq_global_kobject, attr);
926 cpufreq_put_global_kobject();
928 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
930 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
932 struct device *cpu_dev;
934 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
939 cpu_dev = get_cpu_device(cpu);
940 if (WARN_ON(!cpu_dev))
943 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
946 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
948 struct device *cpu_dev;
950 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
952 cpu_dev = get_cpu_device(cpu);
953 if (WARN_ON(!cpu_dev))
956 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
959 /* Add/remove symlinks for all related CPUs */
960 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
965 /* Some related CPUs might not be present (physically hotplugged) */
966 for_each_cpu(j, policy->real_cpus) {
967 if (j == policy->kobj_cpu)
970 ret = add_cpu_dev_symlink(policy, j);
978 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
982 /* Some related CPUs might not be present (physically hotplugged) */
983 for_each_cpu(j, policy->real_cpus) {
984 if (j == policy->kobj_cpu)
987 remove_cpu_dev_symlink(policy, j);
991 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
993 struct freq_attr **drv_attr;
996 /* set up files for this cpu device */
997 drv_attr = cpufreq_driver->attr;
998 while (drv_attr && *drv_attr) {
999 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1004 if (cpufreq_driver->get) {
1005 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1010 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1014 if (cpufreq_driver->bios_limit) {
1015 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1020 return cpufreq_add_dev_symlink(policy);
1023 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1025 struct cpufreq_governor *gov = NULL;
1026 struct cpufreq_policy new_policy;
1028 memcpy(&new_policy, policy, sizeof(*policy));
1030 /* Update governor of new_policy to the governor used before hotplug */
1031 gov = find_governor(policy->last_governor);
1033 pr_debug("Restoring governor %s for cpu %d\n",
1034 policy->governor->name, policy->cpu);
1036 gov = CPUFREQ_DEFAULT_GOVERNOR;
1038 new_policy.governor = gov;
1040 /* Use the default policy if its valid. */
1041 if (cpufreq_driver->setpolicy)
1042 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
1044 /* set default policy */
1045 return cpufreq_set_policy(policy, &new_policy);
1048 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1052 /* Has this CPU been taken care of already? */
1053 if (cpumask_test_cpu(cpu, policy->cpus))
1057 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1059 pr_err("%s: Failed to stop governor\n", __func__);
1064 down_write(&policy->rwsem);
1065 cpumask_set_cpu(cpu, policy->cpus);
1066 up_write(&policy->rwsem);
1069 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1071 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1074 pr_err("%s: Failed to start governor\n", __func__);
1082 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1084 struct device *dev = get_cpu_device(cpu);
1085 struct cpufreq_policy *policy;
1091 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1095 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1096 goto err_free_policy;
1098 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1099 goto err_free_cpumask;
1101 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1102 goto err_free_rcpumask;
1104 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
1107 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1108 goto err_free_real_cpus;
1111 INIT_LIST_HEAD(&policy->policy_list);
1112 init_rwsem(&policy->rwsem);
1113 spin_lock_init(&policy->transition_lock);
1114 init_waitqueue_head(&policy->transition_wait);
1115 init_completion(&policy->kobj_unregister);
1116 INIT_WORK(&policy->update, handle_update);
1120 /* Set this once on allocation */
1121 policy->kobj_cpu = cpu;
1126 free_cpumask_var(policy->real_cpus);
1128 free_cpumask_var(policy->related_cpus);
1130 free_cpumask_var(policy->cpus);
1137 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1139 struct kobject *kobj;
1140 struct completion *cmp;
1143 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1144 CPUFREQ_REMOVE_POLICY, policy);
1146 down_write(&policy->rwsem);
1147 cpufreq_remove_dev_symlink(policy);
1148 kobj = &policy->kobj;
1149 cmp = &policy->kobj_unregister;
1150 up_write(&policy->rwsem);
1154 * We need to make sure that the underlying kobj is
1155 * actually not referenced anymore by anybody before we
1156 * proceed with unloading.
1158 pr_debug("waiting for dropping of refcount\n");
1159 wait_for_completion(cmp);
1160 pr_debug("wait complete\n");
1163 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1165 unsigned long flags;
1168 /* Remove policy from list */
1169 write_lock_irqsave(&cpufreq_driver_lock, flags);
1170 list_del(&policy->policy_list);
1172 for_each_cpu(cpu, policy->related_cpus)
1173 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1174 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1176 cpufreq_policy_put_kobj(policy, notify);
1177 free_cpumask_var(policy->real_cpus);
1178 free_cpumask_var(policy->related_cpus);
1179 free_cpumask_var(policy->cpus);
1183 static int cpufreq_online(unsigned int cpu)
1185 struct cpufreq_policy *policy;
1187 unsigned long flags;
1191 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1193 /* Check if this CPU already has a policy to manage it */
1194 policy = per_cpu(cpufreq_cpu_data, cpu);
1196 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1197 if (!policy_is_inactive(policy))
1198 return cpufreq_add_policy_cpu(policy, cpu);
1200 /* This is the only online CPU for the policy. Start over. */
1202 down_write(&policy->rwsem);
1204 policy->governor = NULL;
1205 up_write(&policy->rwsem);
1208 policy = cpufreq_policy_alloc(cpu);
1213 cpumask_copy(policy->cpus, cpumask_of(cpu));
1215 /* call driver. From then on the cpufreq must be able
1216 * to accept all calls to ->verify and ->setpolicy for this CPU
1218 ret = cpufreq_driver->init(policy);
1220 pr_debug("initialization failed\n");
1221 goto out_free_policy;
1224 down_write(&policy->rwsem);
1227 /* related_cpus should at least include policy->cpus. */
1228 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1229 /* Remember CPUs present at the policy creation time. */
1230 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1234 * affected cpus must always be the one, which are online. We aren't
1235 * managing offline cpus here.
1237 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1240 policy->user_policy.min = policy->min;
1241 policy->user_policy.max = policy->max;
1243 write_lock_irqsave(&cpufreq_driver_lock, flags);
1244 for_each_cpu(j, policy->related_cpus)
1245 per_cpu(cpufreq_cpu_data, j) = policy;
1246 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1249 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1250 policy->cur = cpufreq_driver->get(policy->cpu);
1252 pr_err("%s: ->get() failed\n", __func__);
1253 goto out_exit_policy;
1258 * Sometimes boot loaders set CPU frequency to a value outside of
1259 * frequency table present with cpufreq core. In such cases CPU might be
1260 * unstable if it has to run on that frequency for long duration of time
1261 * and so its better to set it to a frequency which is specified in
1262 * freq-table. This also makes cpufreq stats inconsistent as
1263 * cpufreq-stats would fail to register because current frequency of CPU
1264 * isn't found in freq-table.
1266 * Because we don't want this change to effect boot process badly, we go
1267 * for the next freq which is >= policy->cur ('cur' must be set by now,
1268 * otherwise we will end up setting freq to lowest of the table as 'cur'
1269 * is initialized to zero).
1271 * We are passing target-freq as "policy->cur - 1" otherwise
1272 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1273 * equal to target-freq.
1275 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1277 /* Are we running at unknown frequency ? */
1278 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1279 if (ret == -EINVAL) {
1280 /* Warn user and fix it */
1281 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1282 __func__, policy->cpu, policy->cur);
1283 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1284 CPUFREQ_RELATION_L);
1287 * Reaching here after boot in a few seconds may not
1288 * mean that system will remain stable at "unknown"
1289 * frequency for longer duration. Hence, a BUG_ON().
1292 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1293 __func__, policy->cpu, policy->cur);
1297 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1298 CPUFREQ_START, policy);
1301 ret = cpufreq_add_dev_interface(policy);
1303 goto out_exit_policy;
1304 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1305 CPUFREQ_CREATE_POLICY, policy);
1307 write_lock_irqsave(&cpufreq_driver_lock, flags);
1308 list_add(&policy->policy_list, &cpufreq_policy_list);
1309 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1312 ret = cpufreq_init_policy(policy);
1314 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1315 __func__, cpu, ret);
1316 /* cpufreq_policy_free() will notify based on this */
1318 goto out_exit_policy;
1321 up_write(&policy->rwsem);
1323 kobject_uevent(&policy->kobj, KOBJ_ADD);
1325 /* Callback for handling stuff after policy is ready */
1326 if (cpufreq_driver->ready)
1327 cpufreq_driver->ready(policy);
1329 pr_debug("initialization complete\n");
1334 up_write(&policy->rwsem);
1336 if (cpufreq_driver->exit)
1337 cpufreq_driver->exit(policy);
1339 cpufreq_policy_free(policy, !new_policy);
1344 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1346 * @sif: Subsystem interface structure pointer (not used)
1348 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1350 unsigned cpu = dev->id;
1353 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1355 if (cpu_online(cpu)) {
1356 ret = cpufreq_online(cpu);
1359 * A hotplug notifier will follow and we will handle it as CPU
1360 * online then. For now, just create the sysfs link, unless
1361 * there is no policy or the link is already present.
1363 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1365 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1366 ? add_cpu_dev_symlink(policy, cpu) : 0;
1372 static void cpufreq_offline_prepare(unsigned int cpu)
1374 struct cpufreq_policy *policy;
1376 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1378 policy = cpufreq_cpu_get_raw(cpu);
1380 pr_debug("%s: No cpu_data found\n", __func__);
1385 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1387 pr_err("%s: Failed to stop governor\n", __func__);
1390 down_write(&policy->rwsem);
1391 cpumask_clear_cpu(cpu, policy->cpus);
1393 if (policy_is_inactive(policy)) {
1395 strncpy(policy->last_governor, policy->governor->name,
1397 } else if (cpu == policy->cpu) {
1398 /* Nominate new CPU */
1399 policy->cpu = cpumask_any(policy->cpus);
1401 up_write(&policy->rwsem);
1403 /* Start governor again for active policy */
1404 if (!policy_is_inactive(policy)) {
1406 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1408 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1411 pr_err("%s: Failed to start governor\n", __func__);
1413 } else if (cpufreq_driver->stop_cpu) {
1414 cpufreq_driver->stop_cpu(policy);
1418 static void cpufreq_offline_finish(unsigned int cpu)
1420 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1423 pr_debug("%s: No cpu_data found\n", __func__);
1427 /* Only proceed for inactive policies */
1428 if (!policy_is_inactive(policy))
1431 /* If cpu is last user of policy, free policy */
1433 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1435 pr_err("%s: Failed to exit governor\n", __func__);
1439 * Perform the ->exit() even during light-weight tear-down,
1440 * since this is a core component, and is essential for the
1441 * subsequent light-weight ->init() to succeed.
1443 if (cpufreq_driver->exit)
1444 cpufreq_driver->exit(policy);
1448 * cpufreq_remove_dev - remove a CPU device
1450 * Removes the cpufreq interface for a CPU device.
1452 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1454 unsigned int cpu = dev->id;
1455 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1460 if (cpu_online(cpu)) {
1461 cpufreq_offline_prepare(cpu);
1462 cpufreq_offline_finish(cpu);
1465 cpumask_clear_cpu(cpu, policy->real_cpus);
1467 if (cpumask_empty(policy->real_cpus)) {
1468 cpufreq_policy_free(policy, true);
1472 if (cpu != policy->kobj_cpu) {
1473 remove_cpu_dev_symlink(policy, cpu);
1476 * The CPU owning the policy object is going away. Move it to
1477 * another suitable CPU.
1479 unsigned int new_cpu = cpumask_first(policy->real_cpus);
1480 struct device *new_dev = get_cpu_device(new_cpu);
1482 dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
1484 sysfs_remove_link(&new_dev->kobj, "cpufreq");
1485 policy->kobj_cpu = new_cpu;
1486 WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
1492 static void handle_update(struct work_struct *work)
1494 struct cpufreq_policy *policy =
1495 container_of(work, struct cpufreq_policy, update);
1496 unsigned int cpu = policy->cpu;
1497 pr_debug("handle_update for cpu %u called\n", cpu);
1498 cpufreq_update_policy(cpu);
1502 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1504 * @policy: policy managing CPUs
1505 * @new_freq: CPU frequency the CPU actually runs at
1507 * We adjust to current frequency first, and need to clean up later.
1508 * So either call to cpufreq_update_policy() or schedule handle_update()).
1510 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1511 unsigned int new_freq)
1513 struct cpufreq_freqs freqs;
1515 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1516 policy->cur, new_freq);
1518 freqs.old = policy->cur;
1519 freqs.new = new_freq;
1521 cpufreq_freq_transition_begin(policy, &freqs);
1522 cpufreq_freq_transition_end(policy, &freqs, 0);
1526 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1529 * This is the last known freq, without actually getting it from the driver.
1530 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1532 unsigned int cpufreq_quick_get(unsigned int cpu)
1534 struct cpufreq_policy *policy;
1535 unsigned int ret_freq = 0;
1537 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1538 return cpufreq_driver->get(cpu);
1540 policy = cpufreq_cpu_get(cpu);
1542 ret_freq = policy->cur;
1543 cpufreq_cpu_put(policy);
1548 EXPORT_SYMBOL(cpufreq_quick_get);
1551 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1554 * Just return the max possible frequency for a given CPU.
1556 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1558 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1559 unsigned int ret_freq = 0;
1562 ret_freq = policy->max;
1563 cpufreq_cpu_put(policy);
1568 EXPORT_SYMBOL(cpufreq_quick_get_max);
1570 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1572 unsigned int ret_freq = 0;
1574 if (!cpufreq_driver->get)
1577 ret_freq = cpufreq_driver->get(policy->cpu);
1579 /* Updating inactive policies is invalid, so avoid doing that. */
1580 if (unlikely(policy_is_inactive(policy)))
1583 if (ret_freq && policy->cur &&
1584 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1585 /* verify no discrepancy between actual and
1586 saved value exists */
1587 if (unlikely(ret_freq != policy->cur)) {
1588 cpufreq_out_of_sync(policy, ret_freq);
1589 schedule_work(&policy->update);
1597 * cpufreq_get - get the current CPU frequency (in kHz)
1600 * Get the CPU current (static) CPU frequency
1602 unsigned int cpufreq_get(unsigned int cpu)
1604 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1605 unsigned int ret_freq = 0;
1608 down_read(&policy->rwsem);
1609 ret_freq = __cpufreq_get(policy);
1610 up_read(&policy->rwsem);
1612 cpufreq_cpu_put(policy);
1617 EXPORT_SYMBOL(cpufreq_get);
1619 static struct subsys_interface cpufreq_interface = {
1621 .subsys = &cpu_subsys,
1622 .add_dev = cpufreq_add_dev,
1623 .remove_dev = cpufreq_remove_dev,
1627 * In case platform wants some specific frequency to be configured
1630 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1634 if (!policy->suspend_freq) {
1635 pr_err("%s: suspend_freq can't be zero\n", __func__);
1639 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1640 policy->suspend_freq);
1642 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1643 CPUFREQ_RELATION_H);
1645 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1646 __func__, policy->suspend_freq, ret);
1650 EXPORT_SYMBOL(cpufreq_generic_suspend);
1653 * cpufreq_suspend() - Suspend CPUFreq governors
1655 * Called during system wide Suspend/Hibernate cycles for suspending governors
1656 * as some platforms can't change frequency after this point in suspend cycle.
1657 * Because some of the devices (like: i2c, regulators, etc) they use for
1658 * changing frequency are suspended quickly after this point.
1660 void cpufreq_suspend(void)
1662 struct cpufreq_policy *policy;
1664 if (!cpufreq_driver)
1670 pr_debug("%s: Suspending Governors\n", __func__);
1672 for_each_active_policy(policy) {
1673 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1674 pr_err("%s: Failed to stop governor for policy: %p\n",
1676 else if (cpufreq_driver->suspend
1677 && cpufreq_driver->suspend(policy))
1678 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1683 cpufreq_suspended = true;
1687 * cpufreq_resume() - Resume CPUFreq governors
1689 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1690 * are suspended with cpufreq_suspend().
1692 void cpufreq_resume(void)
1694 struct cpufreq_policy *policy;
1696 if (!cpufreq_driver)
1699 cpufreq_suspended = false;
1704 pr_debug("%s: Resuming Governors\n", __func__);
1706 for_each_active_policy(policy) {
1707 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1708 pr_err("%s: Failed to resume driver: %p\n", __func__,
1710 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1711 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1712 pr_err("%s: Failed to start governor for policy: %p\n",
1717 * schedule call cpufreq_update_policy() for first-online CPU, as that
1718 * wouldn't be hotplugged-out on suspend. It will verify that the
1719 * current freq is in sync with what we believe it to be.
1721 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1722 if (WARN_ON(!policy))
1725 schedule_work(&policy->update);
1729 * cpufreq_get_current_driver - return current driver's name
1731 * Return the name string of the currently loaded cpufreq driver
1734 const char *cpufreq_get_current_driver(void)
1737 return cpufreq_driver->name;
1741 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1744 * cpufreq_get_driver_data - return current driver data
1746 * Return the private data of the currently loaded cpufreq
1747 * driver, or NULL if no cpufreq driver is loaded.
1749 void *cpufreq_get_driver_data(void)
1752 return cpufreq_driver->driver_data;
1756 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1758 /*********************************************************************
1759 * NOTIFIER LISTS INTERFACE *
1760 *********************************************************************/
1763 * cpufreq_register_notifier - register a driver with cpufreq
1764 * @nb: notifier function to register
1765 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1767 * Add a driver to one of two lists: either a list of drivers that
1768 * are notified about clock rate changes (once before and once after
1769 * the transition), or a list of drivers that are notified about
1770 * changes in cpufreq policy.
1772 * This function may sleep, and has the same return conditions as
1773 * blocking_notifier_chain_register.
1775 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1779 if (cpufreq_disabled())
1782 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1785 case CPUFREQ_TRANSITION_NOTIFIER:
1786 ret = srcu_notifier_chain_register(
1787 &cpufreq_transition_notifier_list, nb);
1789 case CPUFREQ_POLICY_NOTIFIER:
1790 ret = blocking_notifier_chain_register(
1791 &cpufreq_policy_notifier_list, nb);
1799 EXPORT_SYMBOL(cpufreq_register_notifier);
1802 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1803 * @nb: notifier block to be unregistered
1804 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1806 * Remove a driver from the CPU frequency notifier list.
1808 * This function may sleep, and has the same return conditions as
1809 * blocking_notifier_chain_unregister.
1811 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1815 if (cpufreq_disabled())
1819 case CPUFREQ_TRANSITION_NOTIFIER:
1820 ret = srcu_notifier_chain_unregister(
1821 &cpufreq_transition_notifier_list, nb);
1823 case CPUFREQ_POLICY_NOTIFIER:
1824 ret = blocking_notifier_chain_unregister(
1825 &cpufreq_policy_notifier_list, nb);
1833 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1836 /*********************************************************************
1838 *********************************************************************/
1840 /* Must set freqs->new to intermediate frequency */
1841 static int __target_intermediate(struct cpufreq_policy *policy,
1842 struct cpufreq_freqs *freqs, int index)
1846 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1848 /* We don't need to switch to intermediate freq */
1852 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1853 __func__, policy->cpu, freqs->old, freqs->new);
1855 cpufreq_freq_transition_begin(policy, freqs);
1856 ret = cpufreq_driver->target_intermediate(policy, index);
1857 cpufreq_freq_transition_end(policy, freqs, ret);
1860 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1866 static int __target_index(struct cpufreq_policy *policy,
1867 struct cpufreq_frequency_table *freq_table, int index)
1869 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1870 unsigned int intermediate_freq = 0;
1871 int retval = -EINVAL;
1874 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1876 /* Handle switching to intermediate frequency */
1877 if (cpufreq_driver->get_intermediate) {
1878 retval = __target_intermediate(policy, &freqs, index);
1882 intermediate_freq = freqs.new;
1883 /* Set old freq to intermediate */
1884 if (intermediate_freq)
1885 freqs.old = freqs.new;
1888 freqs.new = freq_table[index].frequency;
1889 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1890 __func__, policy->cpu, freqs.old, freqs.new);
1892 cpufreq_freq_transition_begin(policy, &freqs);
1895 retval = cpufreq_driver->target_index(policy, index);
1897 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1901 cpufreq_freq_transition_end(policy, &freqs, retval);
1904 * Failed after setting to intermediate freq? Driver should have
1905 * reverted back to initial frequency and so should we. Check
1906 * here for intermediate_freq instead of get_intermediate, in
1907 * case we haven't switched to intermediate freq at all.
1909 if (unlikely(retval && intermediate_freq)) {
1910 freqs.old = intermediate_freq;
1911 freqs.new = policy->restore_freq;
1912 cpufreq_freq_transition_begin(policy, &freqs);
1913 cpufreq_freq_transition_end(policy, &freqs, 0);
1920 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1921 unsigned int target_freq,
1922 unsigned int relation)
1924 unsigned int old_target_freq = target_freq;
1925 int retval = -EINVAL;
1927 if (cpufreq_disabled())
1930 /* Make sure that target_freq is within supported range */
1931 if (target_freq > policy->max)
1932 target_freq = policy->max;
1933 if (target_freq < policy->min)
1934 target_freq = policy->min;
1936 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1937 policy->cpu, target_freq, relation, old_target_freq);
1940 * This might look like a redundant call as we are checking it again
1941 * after finding index. But it is left intentionally for cases where
1942 * exactly same freq is called again and so we can save on few function
1945 if (target_freq == policy->cur)
1948 /* Save last value to restore later on errors */
1949 policy->restore_freq = policy->cur;
1951 if (cpufreq_driver->target)
1952 retval = cpufreq_driver->target(policy, target_freq, relation);
1953 else if (cpufreq_driver->target_index) {
1954 struct cpufreq_frequency_table *freq_table;
1957 freq_table = cpufreq_frequency_get_table(policy->cpu);
1958 if (unlikely(!freq_table)) {
1959 pr_err("%s: Unable to find freq_table\n", __func__);
1963 retval = cpufreq_frequency_table_target(policy, freq_table,
1964 target_freq, relation, &index);
1965 if (unlikely(retval)) {
1966 pr_err("%s: Unable to find matching freq\n", __func__);
1970 if (freq_table[index].frequency == policy->cur) {
1975 retval = __target_index(policy, freq_table, index);
1981 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1983 int cpufreq_driver_target(struct cpufreq_policy *policy,
1984 unsigned int target_freq,
1985 unsigned int relation)
1989 down_write(&policy->rwsem);
1991 ret = __cpufreq_driver_target(policy, target_freq, relation);
1993 up_write(&policy->rwsem);
1997 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1999 static int __cpufreq_governor(struct cpufreq_policy *policy,
2004 /* Only must be defined when default governor is known to have latency
2005 restrictions, like e.g. conservative or ondemand.
2006 That this is the case is already ensured in Kconfig
2008 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2009 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2011 struct cpufreq_governor *gov = NULL;
2014 /* Don't start any governor operations if we are entering suspend */
2015 if (cpufreq_suspended)
2018 * Governor might not be initiated here if ACPI _PPC changed
2019 * notification happened, so check it.
2021 if (!policy->governor)
2024 if (policy->governor->max_transition_latency &&
2025 policy->cpuinfo.transition_latency >
2026 policy->governor->max_transition_latency) {
2030 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2031 policy->governor->name, gov->name);
2032 policy->governor = gov;
2036 if (event == CPUFREQ_GOV_POLICY_INIT)
2037 if (!try_module_get(policy->governor->owner))
2040 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2041 policy->cpu, event);
2043 mutex_lock(&cpufreq_governor_lock);
2044 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2045 || (!policy->governor_enabled
2046 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2047 mutex_unlock(&cpufreq_governor_lock);
2051 if (event == CPUFREQ_GOV_STOP)
2052 policy->governor_enabled = false;
2053 else if (event == CPUFREQ_GOV_START)
2054 policy->governor_enabled = true;
2056 mutex_unlock(&cpufreq_governor_lock);
2058 ret = policy->governor->governor(policy, event);
2061 if (event == CPUFREQ_GOV_POLICY_INIT)
2062 policy->governor->initialized++;
2063 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2064 policy->governor->initialized--;
2066 /* Restore original values */
2067 mutex_lock(&cpufreq_governor_lock);
2068 if (event == CPUFREQ_GOV_STOP)
2069 policy->governor_enabled = true;
2070 else if (event == CPUFREQ_GOV_START)
2071 policy->governor_enabled = false;
2072 mutex_unlock(&cpufreq_governor_lock);
2075 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2076 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2077 module_put(policy->governor->owner);
2082 int cpufreq_register_governor(struct cpufreq_governor *governor)
2089 if (cpufreq_disabled())
2092 mutex_lock(&cpufreq_governor_mutex);
2094 governor->initialized = 0;
2096 if (!find_governor(governor->name)) {
2098 list_add(&governor->governor_list, &cpufreq_governor_list);
2101 mutex_unlock(&cpufreq_governor_mutex);
2104 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2106 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2108 struct cpufreq_policy *policy;
2109 unsigned long flags;
2114 if (cpufreq_disabled())
2117 /* clear last_governor for all inactive policies */
2118 read_lock_irqsave(&cpufreq_driver_lock, flags);
2119 for_each_inactive_policy(policy) {
2120 if (!strcmp(policy->last_governor, governor->name)) {
2121 policy->governor = NULL;
2122 strcpy(policy->last_governor, "\0");
2125 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2127 mutex_lock(&cpufreq_governor_mutex);
2128 list_del(&governor->governor_list);
2129 mutex_unlock(&cpufreq_governor_mutex);
2132 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2135 /*********************************************************************
2136 * POLICY INTERFACE *
2137 *********************************************************************/
2140 * cpufreq_get_policy - get the current cpufreq_policy
2141 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2144 * Reads the current cpufreq policy.
2146 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2148 struct cpufreq_policy *cpu_policy;
2152 cpu_policy = cpufreq_cpu_get(cpu);
2156 memcpy(policy, cpu_policy, sizeof(*policy));
2158 cpufreq_cpu_put(cpu_policy);
2161 EXPORT_SYMBOL(cpufreq_get_policy);
2164 * policy : current policy.
2165 * new_policy: policy to be set.
2167 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2168 struct cpufreq_policy *new_policy)
2170 struct cpufreq_governor *old_gov;
2173 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2174 new_policy->cpu, new_policy->min, new_policy->max);
2176 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2179 * This check works well when we store new min/max freq attributes,
2180 * because new_policy is a copy of policy with one field updated.
2182 if (new_policy->min > new_policy->max)
2185 /* verify the cpu speed can be set within this limit */
2186 ret = cpufreq_driver->verify(new_policy);
2190 /* adjust if necessary - all reasons */
2191 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2192 CPUFREQ_ADJUST, new_policy);
2195 * verify the cpu speed can be set within this limit, which might be
2196 * different to the first one
2198 ret = cpufreq_driver->verify(new_policy);
2202 /* notification of the new policy */
2203 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2204 CPUFREQ_NOTIFY, new_policy);
2206 policy->min = new_policy->min;
2207 policy->max = new_policy->max;
2209 pr_debug("new min and max freqs are %u - %u kHz\n",
2210 policy->min, policy->max);
2212 if (cpufreq_driver->setpolicy) {
2213 policy->policy = new_policy->policy;
2214 pr_debug("setting range\n");
2215 return cpufreq_driver->setpolicy(new_policy);
2218 if (new_policy->governor == policy->governor)
2221 pr_debug("governor switch\n");
2223 /* save old, working values */
2224 old_gov = policy->governor;
2225 /* end old governor */
2227 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2229 /* This can happen due to race with other operations */
2230 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2231 __func__, old_gov->name, ret);
2235 up_write(&policy->rwsem);
2236 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2237 down_write(&policy->rwsem);
2240 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2241 __func__, old_gov->name, ret);
2246 /* start new governor */
2247 policy->governor = new_policy->governor;
2248 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2250 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2254 up_write(&policy->rwsem);
2255 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2256 down_write(&policy->rwsem);
2259 /* new governor failed, so re-start old one */
2260 pr_debug("starting governor %s failed\n", policy->governor->name);
2262 policy->governor = old_gov;
2263 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2264 policy->governor = NULL;
2266 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2272 pr_debug("governor: change or update limits\n");
2273 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2277 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2278 * @cpu: CPU which shall be re-evaluated
2280 * Useful for policy notifiers which have different necessities
2281 * at different times.
2283 int cpufreq_update_policy(unsigned int cpu)
2285 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2286 struct cpufreq_policy new_policy;
2292 down_write(&policy->rwsem);
2294 pr_debug("updating policy for CPU %u\n", cpu);
2295 memcpy(&new_policy, policy, sizeof(*policy));
2296 new_policy.min = policy->user_policy.min;
2297 new_policy.max = policy->user_policy.max;
2300 * BIOS might change freq behind our back
2301 * -> ask driver for current freq and notify governors about a change
2303 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2304 new_policy.cur = cpufreq_driver->get(cpu);
2305 if (WARN_ON(!new_policy.cur)) {
2311 pr_debug("Driver did not initialize current freq\n");
2312 policy->cur = new_policy.cur;
2314 if (policy->cur != new_policy.cur && has_target())
2315 cpufreq_out_of_sync(policy, new_policy.cur);
2319 ret = cpufreq_set_policy(policy, &new_policy);
2322 up_write(&policy->rwsem);
2324 cpufreq_cpu_put(policy);
2327 EXPORT_SYMBOL(cpufreq_update_policy);
2329 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2330 unsigned long action, void *hcpu)
2332 unsigned int cpu = (unsigned long)hcpu;
2334 switch (action & ~CPU_TASKS_FROZEN) {
2336 cpufreq_online(cpu);
2339 case CPU_DOWN_PREPARE:
2340 cpufreq_offline_prepare(cpu);
2344 cpufreq_offline_finish(cpu);
2347 case CPU_DOWN_FAILED:
2348 cpufreq_online(cpu);
2354 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2355 .notifier_call = cpufreq_cpu_callback,
2358 /*********************************************************************
2360 *********************************************************************/
2361 static int cpufreq_boost_set_sw(int state)
2363 struct cpufreq_frequency_table *freq_table;
2364 struct cpufreq_policy *policy;
2367 for_each_active_policy(policy) {
2368 freq_table = cpufreq_frequency_get_table(policy->cpu);
2370 ret = cpufreq_frequency_table_cpuinfo(policy,
2373 pr_err("%s: Policy frequency update failed\n",
2377 policy->user_policy.max = policy->max;
2378 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2385 int cpufreq_boost_trigger_state(int state)
2387 unsigned long flags;
2390 if (cpufreq_driver->boost_enabled == state)
2393 write_lock_irqsave(&cpufreq_driver_lock, flags);
2394 cpufreq_driver->boost_enabled = state;
2395 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2397 ret = cpufreq_driver->set_boost(state);
2399 write_lock_irqsave(&cpufreq_driver_lock, flags);
2400 cpufreq_driver->boost_enabled = !state;
2401 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2403 pr_err("%s: Cannot %s BOOST\n",
2404 __func__, state ? "enable" : "disable");
2410 int cpufreq_boost_supported(void)
2412 if (likely(cpufreq_driver))
2413 return cpufreq_driver->boost_supported;
2417 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2419 int cpufreq_boost_enabled(void)
2421 return cpufreq_driver->boost_enabled;
2423 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2425 /*********************************************************************
2426 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2427 *********************************************************************/
2430 * cpufreq_register_driver - register a CPU Frequency driver
2431 * @driver_data: A struct cpufreq_driver containing the values#
2432 * submitted by the CPU Frequency driver.
2434 * Registers a CPU Frequency driver to this core code. This code
2435 * returns zero on success, -EBUSY when another driver got here first
2436 * (and isn't unregistered in the meantime).
2439 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2441 unsigned long flags;
2444 if (cpufreq_disabled())
2447 if (!driver_data || !driver_data->verify || !driver_data->init ||
2448 !(driver_data->setpolicy || driver_data->target_index ||
2449 driver_data->target) ||
2450 (driver_data->setpolicy && (driver_data->target_index ||
2451 driver_data->target)) ||
2452 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2455 pr_debug("trying to register driver %s\n", driver_data->name);
2457 /* Protect against concurrent CPU online/offline. */
2460 write_lock_irqsave(&cpufreq_driver_lock, flags);
2461 if (cpufreq_driver) {
2462 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2466 cpufreq_driver = driver_data;
2467 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2469 if (driver_data->setpolicy)
2470 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2472 if (cpufreq_boost_supported()) {
2474 * Check if driver provides function to enable boost -
2475 * if not, use cpufreq_boost_set_sw as default
2477 if (!cpufreq_driver->set_boost)
2478 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2480 ret = cpufreq_sysfs_create_file(&boost.attr);
2482 pr_err("%s: cannot register global BOOST sysfs file\n",
2484 goto err_null_driver;
2488 ret = subsys_interface_register(&cpufreq_interface);
2490 goto err_boost_unreg;
2492 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2493 list_empty(&cpufreq_policy_list)) {
2494 /* if all ->init() calls failed, unregister */
2495 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2500 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2501 pr_debug("driver %s up and running\n", driver_data->name);
2508 subsys_interface_unregister(&cpufreq_interface);
2510 if (cpufreq_boost_supported())
2511 cpufreq_sysfs_remove_file(&boost.attr);
2513 write_lock_irqsave(&cpufreq_driver_lock, flags);
2514 cpufreq_driver = NULL;
2515 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2518 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2521 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2523 * Unregister the current CPUFreq driver. Only call this if you have
2524 * the right to do so, i.e. if you have succeeded in initialising before!
2525 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2526 * currently not initialised.
2528 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2530 unsigned long flags;
2532 if (!cpufreq_driver || (driver != cpufreq_driver))
2535 pr_debug("unregistering driver %s\n", driver->name);
2537 /* Protect against concurrent cpu hotplug */
2539 subsys_interface_unregister(&cpufreq_interface);
2540 if (cpufreq_boost_supported())
2541 cpufreq_sysfs_remove_file(&boost.attr);
2543 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2545 write_lock_irqsave(&cpufreq_driver_lock, flags);
2547 cpufreq_driver = NULL;
2549 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2554 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2557 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2558 * or mutexes when secondary CPUs are halted.
2560 static struct syscore_ops cpufreq_syscore_ops = {
2561 .shutdown = cpufreq_suspend,
2564 static int __init cpufreq_core_init(void)
2566 if (cpufreq_disabled())
2569 cpufreq_global_kobject = kobject_create();
2570 BUG_ON(!cpufreq_global_kobject);
2572 register_syscore_ops(&cpufreq_syscore_ops);
2576 core_initcall(cpufreq_core_init);