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)
523 if (cpufreq_driver->setpolicy) {
524 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
525 *policy = CPUFREQ_POLICY_PERFORMANCE;
527 } else if (!strncasecmp(str_governor, "powersave",
529 *policy = CPUFREQ_POLICY_POWERSAVE;
533 struct cpufreq_governor *t;
535 mutex_lock(&cpufreq_governor_mutex);
537 t = find_governor(str_governor);
542 mutex_unlock(&cpufreq_governor_mutex);
543 ret = request_module("cpufreq_%s", str_governor);
544 mutex_lock(&cpufreq_governor_mutex);
547 t = find_governor(str_governor);
555 mutex_unlock(&cpufreq_governor_mutex);
561 * cpufreq_per_cpu_attr_read() / show_##file_name() -
562 * print out cpufreq information
564 * Write out information from cpufreq_driver->policy[cpu]; object must be
568 #define show_one(file_name, object) \
569 static ssize_t show_##file_name \
570 (struct cpufreq_policy *policy, char *buf) \
572 return sprintf(buf, "%u\n", policy->object); \
575 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
576 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
577 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
578 show_one(scaling_min_freq, min);
579 show_one(scaling_max_freq, max);
581 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
585 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
586 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
588 ret = sprintf(buf, "%u\n", policy->cur);
592 static int cpufreq_set_policy(struct cpufreq_policy *policy,
593 struct cpufreq_policy *new_policy);
596 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
598 #define store_one(file_name, object) \
599 static ssize_t store_##file_name \
600 (struct cpufreq_policy *policy, const char *buf, size_t count) \
603 struct cpufreq_policy new_policy; \
605 memcpy(&new_policy, policy, sizeof(*policy)); \
607 ret = sscanf(buf, "%u", &new_policy.object); \
611 temp = new_policy.object; \
612 ret = cpufreq_set_policy(policy, &new_policy); \
614 policy->user_policy.object = temp; \
616 return ret ? ret : count; \
619 store_one(scaling_min_freq, min);
620 store_one(scaling_max_freq, max);
623 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
625 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
628 unsigned int cur_freq = __cpufreq_get(policy);
630 return sprintf(buf, "<unknown>");
631 return sprintf(buf, "%u\n", cur_freq);
635 * show_scaling_governor - show the current policy for the specified CPU
637 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
639 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
640 return sprintf(buf, "powersave\n");
641 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
642 return sprintf(buf, "performance\n");
643 else if (policy->governor)
644 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
645 policy->governor->name);
650 * store_scaling_governor - store policy for the specified CPU
652 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
653 const char *buf, size_t count)
656 char str_governor[16];
657 struct cpufreq_policy new_policy;
659 memcpy(&new_policy, policy, sizeof(*policy));
661 ret = sscanf(buf, "%15s", str_governor);
665 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
666 &new_policy.governor))
669 ret = cpufreq_set_policy(policy, &new_policy);
670 return ret ? ret : count;
674 * show_scaling_driver - show the cpufreq driver currently loaded
676 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
678 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
682 * show_scaling_available_governors - show the available CPUfreq governors
684 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
688 struct cpufreq_governor *t;
691 i += sprintf(buf, "performance powersave");
695 for_each_governor(t) {
696 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
697 - (CPUFREQ_NAME_LEN + 2)))
699 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
702 i += sprintf(&buf[i], "\n");
706 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
711 for_each_cpu(cpu, mask) {
713 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
714 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
715 if (i >= (PAGE_SIZE - 5))
718 i += sprintf(&buf[i], "\n");
721 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
724 * show_related_cpus - show the CPUs affected by each transition even if
725 * hw coordination is in use
727 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
729 return cpufreq_show_cpus(policy->related_cpus, buf);
733 * show_affected_cpus - show the CPUs affected by each transition
735 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
737 return cpufreq_show_cpus(policy->cpus, buf);
740 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
741 const char *buf, size_t count)
743 unsigned int freq = 0;
746 if (!policy->governor || !policy->governor->store_setspeed)
749 ret = sscanf(buf, "%u", &freq);
753 policy->governor->store_setspeed(policy, freq);
758 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
760 if (!policy->governor || !policy->governor->show_setspeed)
761 return sprintf(buf, "<unsupported>\n");
763 return policy->governor->show_setspeed(policy, buf);
767 * show_bios_limit - show the current cpufreq HW/BIOS limitation
769 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
773 if (cpufreq_driver->bios_limit) {
774 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
776 return sprintf(buf, "%u\n", limit);
778 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
781 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
782 cpufreq_freq_attr_ro(cpuinfo_min_freq);
783 cpufreq_freq_attr_ro(cpuinfo_max_freq);
784 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
785 cpufreq_freq_attr_ro(scaling_available_governors);
786 cpufreq_freq_attr_ro(scaling_driver);
787 cpufreq_freq_attr_ro(scaling_cur_freq);
788 cpufreq_freq_attr_ro(bios_limit);
789 cpufreq_freq_attr_ro(related_cpus);
790 cpufreq_freq_attr_ro(affected_cpus);
791 cpufreq_freq_attr_rw(scaling_min_freq);
792 cpufreq_freq_attr_rw(scaling_max_freq);
793 cpufreq_freq_attr_rw(scaling_governor);
794 cpufreq_freq_attr_rw(scaling_setspeed);
796 static struct attribute *default_attrs[] = {
797 &cpuinfo_min_freq.attr,
798 &cpuinfo_max_freq.attr,
799 &cpuinfo_transition_latency.attr,
800 &scaling_min_freq.attr,
801 &scaling_max_freq.attr,
804 &scaling_governor.attr,
805 &scaling_driver.attr,
806 &scaling_available_governors.attr,
807 &scaling_setspeed.attr,
811 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
812 #define to_attr(a) container_of(a, struct freq_attr, attr)
814 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
816 struct cpufreq_policy *policy = to_policy(kobj);
817 struct freq_attr *fattr = to_attr(attr);
820 down_read(&policy->rwsem);
823 ret = fattr->show(policy, buf);
827 up_read(&policy->rwsem);
832 static ssize_t store(struct kobject *kobj, struct attribute *attr,
833 const char *buf, size_t count)
835 struct cpufreq_policy *policy = to_policy(kobj);
836 struct freq_attr *fattr = to_attr(attr);
837 ssize_t ret = -EINVAL;
841 if (!cpu_online(policy->cpu))
844 down_write(&policy->rwsem);
846 /* Updating inactive policies is invalid, so avoid doing that. */
847 if (unlikely(policy_is_inactive(policy))) {
849 goto unlock_policy_rwsem;
853 ret = fattr->store(policy, buf, count);
858 up_write(&policy->rwsem);
865 static void cpufreq_sysfs_release(struct kobject *kobj)
867 struct cpufreq_policy *policy = to_policy(kobj);
868 pr_debug("last reference is dropped\n");
869 complete(&policy->kobj_unregister);
872 static const struct sysfs_ops sysfs_ops = {
877 static struct kobj_type ktype_cpufreq = {
878 .sysfs_ops = &sysfs_ops,
879 .default_attrs = default_attrs,
880 .release = cpufreq_sysfs_release,
883 struct kobject *cpufreq_global_kobject;
884 EXPORT_SYMBOL(cpufreq_global_kobject);
886 static int cpufreq_global_kobject_usage;
888 int cpufreq_get_global_kobject(void)
890 if (!cpufreq_global_kobject_usage++)
891 return kobject_add(cpufreq_global_kobject,
892 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
896 EXPORT_SYMBOL(cpufreq_get_global_kobject);
898 void cpufreq_put_global_kobject(void)
900 if (!--cpufreq_global_kobject_usage)
901 kobject_del(cpufreq_global_kobject);
903 EXPORT_SYMBOL(cpufreq_put_global_kobject);
905 int cpufreq_sysfs_create_file(const struct attribute *attr)
907 int ret = cpufreq_get_global_kobject();
910 ret = sysfs_create_file(cpufreq_global_kobject, attr);
912 cpufreq_put_global_kobject();
917 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
919 void cpufreq_sysfs_remove_file(const struct attribute *attr)
921 sysfs_remove_file(cpufreq_global_kobject, attr);
922 cpufreq_put_global_kobject();
924 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
926 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
928 struct device *cpu_dev;
930 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
935 cpu_dev = get_cpu_device(cpu);
936 if (WARN_ON(!cpu_dev))
939 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
942 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
944 struct device *cpu_dev;
946 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
948 cpu_dev = get_cpu_device(cpu);
949 if (WARN_ON(!cpu_dev))
952 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
955 /* Add/remove symlinks for all related CPUs */
956 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
961 /* Some related CPUs might not be present (physically hotplugged) */
962 for_each_cpu(j, policy->real_cpus) {
963 if (j == policy->kobj_cpu)
966 ret = add_cpu_dev_symlink(policy, j);
974 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
978 /* Some related CPUs might not be present (physically hotplugged) */
979 for_each_cpu(j, policy->real_cpus) {
980 if (j == policy->kobj_cpu)
983 remove_cpu_dev_symlink(policy, j);
987 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
989 struct freq_attr **drv_attr;
992 /* set up files for this cpu device */
993 drv_attr = cpufreq_driver->attr;
994 while (drv_attr && *drv_attr) {
995 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1000 if (cpufreq_driver->get) {
1001 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1006 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1010 if (cpufreq_driver->bios_limit) {
1011 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1016 return cpufreq_add_dev_symlink(policy);
1019 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1021 struct cpufreq_governor *gov = NULL;
1022 struct cpufreq_policy new_policy;
1024 memcpy(&new_policy, policy, sizeof(*policy));
1026 /* Update governor of new_policy to the governor used before hotplug */
1027 gov = find_governor(policy->last_governor);
1029 pr_debug("Restoring governor %s for cpu %d\n",
1030 policy->governor->name, policy->cpu);
1032 gov = CPUFREQ_DEFAULT_GOVERNOR;
1034 new_policy.governor = gov;
1036 /* Use the default policy if its valid. */
1037 if (cpufreq_driver->setpolicy)
1038 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
1040 /* set default policy */
1041 return cpufreq_set_policy(policy, &new_policy);
1044 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1048 /* Has this CPU been taken care of already? */
1049 if (cpumask_test_cpu(cpu, policy->cpus))
1053 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1055 pr_err("%s: Failed to stop governor\n", __func__);
1060 down_write(&policy->rwsem);
1061 cpumask_set_cpu(cpu, policy->cpus);
1062 up_write(&policy->rwsem);
1065 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1067 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1070 pr_err("%s: Failed to start governor\n", __func__);
1078 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1080 struct device *dev = get_cpu_device(cpu);
1081 struct cpufreq_policy *policy;
1087 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1091 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1092 goto err_free_policy;
1094 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1095 goto err_free_cpumask;
1097 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1098 goto err_free_rcpumask;
1100 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
1103 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1104 goto err_free_real_cpus;
1107 INIT_LIST_HEAD(&policy->policy_list);
1108 init_rwsem(&policy->rwsem);
1109 spin_lock_init(&policy->transition_lock);
1110 init_waitqueue_head(&policy->transition_wait);
1111 init_completion(&policy->kobj_unregister);
1112 INIT_WORK(&policy->update, handle_update);
1116 /* Set this once on allocation */
1117 policy->kobj_cpu = cpu;
1122 free_cpumask_var(policy->real_cpus);
1124 free_cpumask_var(policy->related_cpus);
1126 free_cpumask_var(policy->cpus);
1133 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1135 struct kobject *kobj;
1136 struct completion *cmp;
1139 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1140 CPUFREQ_REMOVE_POLICY, policy);
1142 down_write(&policy->rwsem);
1143 cpufreq_remove_dev_symlink(policy);
1144 kobj = &policy->kobj;
1145 cmp = &policy->kobj_unregister;
1146 up_write(&policy->rwsem);
1150 * We need to make sure that the underlying kobj is
1151 * actually not referenced anymore by anybody before we
1152 * proceed with unloading.
1154 pr_debug("waiting for dropping of refcount\n");
1155 wait_for_completion(cmp);
1156 pr_debug("wait complete\n");
1159 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1161 unsigned long flags;
1164 /* Remove policy from list */
1165 write_lock_irqsave(&cpufreq_driver_lock, flags);
1166 list_del(&policy->policy_list);
1168 for_each_cpu(cpu, policy->related_cpus)
1169 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1170 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1172 cpufreq_policy_put_kobj(policy, notify);
1173 free_cpumask_var(policy->real_cpus);
1174 free_cpumask_var(policy->related_cpus);
1175 free_cpumask_var(policy->cpus);
1179 static int cpufreq_online(unsigned int cpu)
1181 struct cpufreq_policy *policy;
1183 unsigned long flags;
1187 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1189 /* Check if this CPU already has a policy to manage it */
1190 policy = per_cpu(cpufreq_cpu_data, cpu);
1192 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1193 if (!policy_is_inactive(policy))
1194 return cpufreq_add_policy_cpu(policy, cpu);
1196 /* This is the only online CPU for the policy. Start over. */
1198 down_write(&policy->rwsem);
1200 policy->governor = NULL;
1201 up_write(&policy->rwsem);
1204 policy = cpufreq_policy_alloc(cpu);
1209 cpumask_copy(policy->cpus, cpumask_of(cpu));
1211 /* call driver. From then on the cpufreq must be able
1212 * to accept all calls to ->verify and ->setpolicy for this CPU
1214 ret = cpufreq_driver->init(policy);
1216 pr_debug("initialization failed\n");
1217 goto out_free_policy;
1220 down_write(&policy->rwsem);
1223 /* related_cpus should at least include policy->cpus. */
1224 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1225 /* Remember CPUs present at the policy creation time. */
1226 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1230 * affected cpus must always be the one, which are online. We aren't
1231 * managing offline cpus here.
1233 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1236 policy->user_policy.min = policy->min;
1237 policy->user_policy.max = policy->max;
1239 write_lock_irqsave(&cpufreq_driver_lock, flags);
1240 for_each_cpu(j, policy->related_cpus)
1241 per_cpu(cpufreq_cpu_data, j) = policy;
1242 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1245 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1246 policy->cur = cpufreq_driver->get(policy->cpu);
1248 pr_err("%s: ->get() failed\n", __func__);
1249 goto out_exit_policy;
1254 * Sometimes boot loaders set CPU frequency to a value outside of
1255 * frequency table present with cpufreq core. In such cases CPU might be
1256 * unstable if it has to run on that frequency for long duration of time
1257 * and so its better to set it to a frequency which is specified in
1258 * freq-table. This also makes cpufreq stats inconsistent as
1259 * cpufreq-stats would fail to register because current frequency of CPU
1260 * isn't found in freq-table.
1262 * Because we don't want this change to effect boot process badly, we go
1263 * for the next freq which is >= policy->cur ('cur' must be set by now,
1264 * otherwise we will end up setting freq to lowest of the table as 'cur'
1265 * is initialized to zero).
1267 * We are passing target-freq as "policy->cur - 1" otherwise
1268 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1269 * equal to target-freq.
1271 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1273 /* Are we running at unknown frequency ? */
1274 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1275 if (ret == -EINVAL) {
1276 /* Warn user and fix it */
1277 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1278 __func__, policy->cpu, policy->cur);
1279 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1280 CPUFREQ_RELATION_L);
1283 * Reaching here after boot in a few seconds may not
1284 * mean that system will remain stable at "unknown"
1285 * frequency for longer duration. Hence, a BUG_ON().
1288 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1289 __func__, policy->cpu, policy->cur);
1293 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1294 CPUFREQ_START, policy);
1297 ret = cpufreq_add_dev_interface(policy);
1299 goto out_exit_policy;
1300 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1301 CPUFREQ_CREATE_POLICY, policy);
1303 write_lock_irqsave(&cpufreq_driver_lock, flags);
1304 list_add(&policy->policy_list, &cpufreq_policy_list);
1305 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1308 ret = cpufreq_init_policy(policy);
1310 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1311 __func__, cpu, ret);
1312 /* cpufreq_policy_free() will notify based on this */
1314 goto out_exit_policy;
1317 up_write(&policy->rwsem);
1319 kobject_uevent(&policy->kobj, KOBJ_ADD);
1321 /* Callback for handling stuff after policy is ready */
1322 if (cpufreq_driver->ready)
1323 cpufreq_driver->ready(policy);
1325 pr_debug("initialization complete\n");
1330 up_write(&policy->rwsem);
1332 if (cpufreq_driver->exit)
1333 cpufreq_driver->exit(policy);
1335 cpufreq_policy_free(policy, !new_policy);
1340 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1342 * @sif: Subsystem interface structure pointer (not used)
1344 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1346 unsigned cpu = dev->id;
1349 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1351 if (cpu_online(cpu)) {
1352 ret = cpufreq_online(cpu);
1355 * A hotplug notifier will follow and we will handle it as CPU
1356 * online then. For now, just create the sysfs link, unless
1357 * there is no policy or the link is already present.
1359 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1361 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1362 ? add_cpu_dev_symlink(policy, cpu) : 0;
1368 static void cpufreq_offline_prepare(unsigned int cpu)
1370 struct cpufreq_policy *policy;
1372 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1374 policy = cpufreq_cpu_get_raw(cpu);
1376 pr_debug("%s: No cpu_data found\n", __func__);
1381 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1383 pr_err("%s: Failed to stop governor\n", __func__);
1386 down_write(&policy->rwsem);
1387 cpumask_clear_cpu(cpu, policy->cpus);
1389 if (policy_is_inactive(policy)) {
1391 strncpy(policy->last_governor, policy->governor->name,
1393 } else if (cpu == policy->cpu) {
1394 /* Nominate new CPU */
1395 policy->cpu = cpumask_any(policy->cpus);
1397 up_write(&policy->rwsem);
1399 /* Start governor again for active policy */
1400 if (!policy_is_inactive(policy)) {
1402 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1404 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1407 pr_err("%s: Failed to start governor\n", __func__);
1409 } else if (cpufreq_driver->stop_cpu) {
1410 cpufreq_driver->stop_cpu(policy);
1414 static void cpufreq_offline_finish(unsigned int cpu)
1416 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1419 pr_debug("%s: No cpu_data found\n", __func__);
1423 /* Only proceed for inactive policies */
1424 if (!policy_is_inactive(policy))
1427 /* If cpu is last user of policy, free policy */
1429 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1431 pr_err("%s: Failed to exit governor\n", __func__);
1435 * Perform the ->exit() even during light-weight tear-down,
1436 * since this is a core component, and is essential for the
1437 * subsequent light-weight ->init() to succeed.
1439 if (cpufreq_driver->exit)
1440 cpufreq_driver->exit(policy);
1444 * cpufreq_remove_dev - remove a CPU device
1446 * Removes the cpufreq interface for a CPU device.
1448 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1450 unsigned int cpu = dev->id;
1451 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1456 if (cpu_online(cpu)) {
1457 cpufreq_offline_prepare(cpu);
1458 cpufreq_offline_finish(cpu);
1461 cpumask_clear_cpu(cpu, policy->real_cpus);
1463 if (cpumask_empty(policy->real_cpus)) {
1464 cpufreq_policy_free(policy, true);
1468 if (cpu != policy->kobj_cpu) {
1469 remove_cpu_dev_symlink(policy, cpu);
1472 * The CPU owning the policy object is going away. Move it to
1473 * another suitable CPU.
1475 unsigned int new_cpu = cpumask_first(policy->real_cpus);
1476 struct device *new_dev = get_cpu_device(new_cpu);
1478 dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
1480 sysfs_remove_link(&new_dev->kobj, "cpufreq");
1481 policy->kobj_cpu = new_cpu;
1482 WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
1486 static void handle_update(struct work_struct *work)
1488 struct cpufreq_policy *policy =
1489 container_of(work, struct cpufreq_policy, update);
1490 unsigned int cpu = policy->cpu;
1491 pr_debug("handle_update for cpu %u called\n", cpu);
1492 cpufreq_update_policy(cpu);
1496 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1498 * @policy: policy managing CPUs
1499 * @new_freq: CPU frequency the CPU actually runs at
1501 * We adjust to current frequency first, and need to clean up later.
1502 * So either call to cpufreq_update_policy() or schedule handle_update()).
1504 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1505 unsigned int new_freq)
1507 struct cpufreq_freqs freqs;
1509 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1510 policy->cur, new_freq);
1512 freqs.old = policy->cur;
1513 freqs.new = new_freq;
1515 cpufreq_freq_transition_begin(policy, &freqs);
1516 cpufreq_freq_transition_end(policy, &freqs, 0);
1520 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1523 * This is the last known freq, without actually getting it from the driver.
1524 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1526 unsigned int cpufreq_quick_get(unsigned int cpu)
1528 struct cpufreq_policy *policy;
1529 unsigned int ret_freq = 0;
1531 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1532 return cpufreq_driver->get(cpu);
1534 policy = cpufreq_cpu_get(cpu);
1536 ret_freq = policy->cur;
1537 cpufreq_cpu_put(policy);
1542 EXPORT_SYMBOL(cpufreq_quick_get);
1545 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1548 * Just return the max possible frequency for a given CPU.
1550 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1552 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1553 unsigned int ret_freq = 0;
1556 ret_freq = policy->max;
1557 cpufreq_cpu_put(policy);
1562 EXPORT_SYMBOL(cpufreq_quick_get_max);
1564 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1566 unsigned int ret_freq = 0;
1568 if (!cpufreq_driver->get)
1571 ret_freq = cpufreq_driver->get(policy->cpu);
1573 /* Updating inactive policies is invalid, so avoid doing that. */
1574 if (unlikely(policy_is_inactive(policy)))
1577 if (ret_freq && policy->cur &&
1578 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1579 /* verify no discrepancy between actual and
1580 saved value exists */
1581 if (unlikely(ret_freq != policy->cur)) {
1582 cpufreq_out_of_sync(policy, ret_freq);
1583 schedule_work(&policy->update);
1591 * cpufreq_get - get the current CPU frequency (in kHz)
1594 * Get the CPU current (static) CPU frequency
1596 unsigned int cpufreq_get(unsigned int cpu)
1598 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1599 unsigned int ret_freq = 0;
1602 down_read(&policy->rwsem);
1603 ret_freq = __cpufreq_get(policy);
1604 up_read(&policy->rwsem);
1606 cpufreq_cpu_put(policy);
1611 EXPORT_SYMBOL(cpufreq_get);
1613 static struct subsys_interface cpufreq_interface = {
1615 .subsys = &cpu_subsys,
1616 .add_dev = cpufreq_add_dev,
1617 .remove_dev = cpufreq_remove_dev,
1621 * In case platform wants some specific frequency to be configured
1624 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1628 if (!policy->suspend_freq) {
1629 pr_err("%s: suspend_freq can't be zero\n", __func__);
1633 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1634 policy->suspend_freq);
1636 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1637 CPUFREQ_RELATION_H);
1639 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1640 __func__, policy->suspend_freq, ret);
1644 EXPORT_SYMBOL(cpufreq_generic_suspend);
1647 * cpufreq_suspend() - Suspend CPUFreq governors
1649 * Called during system wide Suspend/Hibernate cycles for suspending governors
1650 * as some platforms can't change frequency after this point in suspend cycle.
1651 * Because some of the devices (like: i2c, regulators, etc) they use for
1652 * changing frequency are suspended quickly after this point.
1654 void cpufreq_suspend(void)
1656 struct cpufreq_policy *policy;
1658 if (!cpufreq_driver)
1664 pr_debug("%s: Suspending Governors\n", __func__);
1666 for_each_active_policy(policy) {
1667 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1668 pr_err("%s: Failed to stop governor for policy: %p\n",
1670 else if (cpufreq_driver->suspend
1671 && cpufreq_driver->suspend(policy))
1672 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1677 cpufreq_suspended = true;
1681 * cpufreq_resume() - Resume CPUFreq governors
1683 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1684 * are suspended with cpufreq_suspend().
1686 void cpufreq_resume(void)
1688 struct cpufreq_policy *policy;
1690 if (!cpufreq_driver)
1693 cpufreq_suspended = false;
1698 pr_debug("%s: Resuming Governors\n", __func__);
1700 for_each_active_policy(policy) {
1701 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1702 pr_err("%s: Failed to resume driver: %p\n", __func__,
1704 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1705 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1706 pr_err("%s: Failed to start governor for policy: %p\n",
1711 * schedule call cpufreq_update_policy() for first-online CPU, as that
1712 * wouldn't be hotplugged-out on suspend. It will verify that the
1713 * current freq is in sync with what we believe it to be.
1715 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1716 if (WARN_ON(!policy))
1719 schedule_work(&policy->update);
1723 * cpufreq_get_current_driver - return current driver's name
1725 * Return the name string of the currently loaded cpufreq driver
1728 const char *cpufreq_get_current_driver(void)
1731 return cpufreq_driver->name;
1735 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1738 * cpufreq_get_driver_data - return current driver data
1740 * Return the private data of the currently loaded cpufreq
1741 * driver, or NULL if no cpufreq driver is loaded.
1743 void *cpufreq_get_driver_data(void)
1746 return cpufreq_driver->driver_data;
1750 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1752 /*********************************************************************
1753 * NOTIFIER LISTS INTERFACE *
1754 *********************************************************************/
1757 * cpufreq_register_notifier - register a driver with cpufreq
1758 * @nb: notifier function to register
1759 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1761 * Add a driver to one of two lists: either a list of drivers that
1762 * are notified about clock rate changes (once before and once after
1763 * the transition), or a list of drivers that are notified about
1764 * changes in cpufreq policy.
1766 * This function may sleep, and has the same return conditions as
1767 * blocking_notifier_chain_register.
1769 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1773 if (cpufreq_disabled())
1776 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1779 case CPUFREQ_TRANSITION_NOTIFIER:
1780 ret = srcu_notifier_chain_register(
1781 &cpufreq_transition_notifier_list, nb);
1783 case CPUFREQ_POLICY_NOTIFIER:
1784 ret = blocking_notifier_chain_register(
1785 &cpufreq_policy_notifier_list, nb);
1793 EXPORT_SYMBOL(cpufreq_register_notifier);
1796 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1797 * @nb: notifier block to be unregistered
1798 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1800 * Remove a driver from the CPU frequency notifier list.
1802 * This function may sleep, and has the same return conditions as
1803 * blocking_notifier_chain_unregister.
1805 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1809 if (cpufreq_disabled())
1813 case CPUFREQ_TRANSITION_NOTIFIER:
1814 ret = srcu_notifier_chain_unregister(
1815 &cpufreq_transition_notifier_list, nb);
1817 case CPUFREQ_POLICY_NOTIFIER:
1818 ret = blocking_notifier_chain_unregister(
1819 &cpufreq_policy_notifier_list, nb);
1827 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1830 /*********************************************************************
1832 *********************************************************************/
1834 /* Must set freqs->new to intermediate frequency */
1835 static int __target_intermediate(struct cpufreq_policy *policy,
1836 struct cpufreq_freqs *freqs, int index)
1840 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1842 /* We don't need to switch to intermediate freq */
1846 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1847 __func__, policy->cpu, freqs->old, freqs->new);
1849 cpufreq_freq_transition_begin(policy, freqs);
1850 ret = cpufreq_driver->target_intermediate(policy, index);
1851 cpufreq_freq_transition_end(policy, freqs, ret);
1854 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1860 static int __target_index(struct cpufreq_policy *policy,
1861 struct cpufreq_frequency_table *freq_table, int index)
1863 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1864 unsigned int intermediate_freq = 0;
1865 int retval = -EINVAL;
1868 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1870 /* Handle switching to intermediate frequency */
1871 if (cpufreq_driver->get_intermediate) {
1872 retval = __target_intermediate(policy, &freqs, index);
1876 intermediate_freq = freqs.new;
1877 /* Set old freq to intermediate */
1878 if (intermediate_freq)
1879 freqs.old = freqs.new;
1882 freqs.new = freq_table[index].frequency;
1883 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1884 __func__, policy->cpu, freqs.old, freqs.new);
1886 cpufreq_freq_transition_begin(policy, &freqs);
1889 retval = cpufreq_driver->target_index(policy, index);
1891 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1895 cpufreq_freq_transition_end(policy, &freqs, retval);
1898 * Failed after setting to intermediate freq? Driver should have
1899 * reverted back to initial frequency and so should we. Check
1900 * here for intermediate_freq instead of get_intermediate, in
1901 * case we haven't switched to intermediate freq at all.
1903 if (unlikely(retval && intermediate_freq)) {
1904 freqs.old = intermediate_freq;
1905 freqs.new = policy->restore_freq;
1906 cpufreq_freq_transition_begin(policy, &freqs);
1907 cpufreq_freq_transition_end(policy, &freqs, 0);
1914 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1915 unsigned int target_freq,
1916 unsigned int relation)
1918 unsigned int old_target_freq = target_freq;
1919 int retval = -EINVAL;
1921 if (cpufreq_disabled())
1924 /* Make sure that target_freq is within supported range */
1925 if (target_freq > policy->max)
1926 target_freq = policy->max;
1927 if (target_freq < policy->min)
1928 target_freq = policy->min;
1930 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1931 policy->cpu, target_freq, relation, old_target_freq);
1934 * This might look like a redundant call as we are checking it again
1935 * after finding index. But it is left intentionally for cases where
1936 * exactly same freq is called again and so we can save on few function
1939 if (target_freq == policy->cur)
1942 /* Save last value to restore later on errors */
1943 policy->restore_freq = policy->cur;
1945 if (cpufreq_driver->target)
1946 retval = cpufreq_driver->target(policy, target_freq, relation);
1947 else if (cpufreq_driver->target_index) {
1948 struct cpufreq_frequency_table *freq_table;
1951 freq_table = cpufreq_frequency_get_table(policy->cpu);
1952 if (unlikely(!freq_table)) {
1953 pr_err("%s: Unable to find freq_table\n", __func__);
1957 retval = cpufreq_frequency_table_target(policy, freq_table,
1958 target_freq, relation, &index);
1959 if (unlikely(retval)) {
1960 pr_err("%s: Unable to find matching freq\n", __func__);
1964 if (freq_table[index].frequency == policy->cur) {
1969 retval = __target_index(policy, freq_table, index);
1975 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1977 int cpufreq_driver_target(struct cpufreq_policy *policy,
1978 unsigned int target_freq,
1979 unsigned int relation)
1983 down_write(&policy->rwsem);
1985 ret = __cpufreq_driver_target(policy, target_freq, relation);
1987 up_write(&policy->rwsem);
1991 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1993 static int __cpufreq_governor(struct cpufreq_policy *policy,
1998 /* Only must be defined when default governor is known to have latency
1999 restrictions, like e.g. conservative or ondemand.
2000 That this is the case is already ensured in Kconfig
2002 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2003 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2005 struct cpufreq_governor *gov = NULL;
2008 /* Don't start any governor operations if we are entering suspend */
2009 if (cpufreq_suspended)
2012 * Governor might not be initiated here if ACPI _PPC changed
2013 * notification happened, so check it.
2015 if (!policy->governor)
2018 if (policy->governor->max_transition_latency &&
2019 policy->cpuinfo.transition_latency >
2020 policy->governor->max_transition_latency) {
2024 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2025 policy->governor->name, gov->name);
2026 policy->governor = gov;
2030 if (event == CPUFREQ_GOV_POLICY_INIT)
2031 if (!try_module_get(policy->governor->owner))
2034 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2035 policy->cpu, event);
2037 mutex_lock(&cpufreq_governor_lock);
2038 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2039 || (!policy->governor_enabled
2040 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2041 mutex_unlock(&cpufreq_governor_lock);
2045 if (event == CPUFREQ_GOV_STOP)
2046 policy->governor_enabled = false;
2047 else if (event == CPUFREQ_GOV_START)
2048 policy->governor_enabled = true;
2050 mutex_unlock(&cpufreq_governor_lock);
2052 ret = policy->governor->governor(policy, event);
2055 if (event == CPUFREQ_GOV_POLICY_INIT)
2056 policy->governor->initialized++;
2057 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2058 policy->governor->initialized--;
2060 /* Restore original values */
2061 mutex_lock(&cpufreq_governor_lock);
2062 if (event == CPUFREQ_GOV_STOP)
2063 policy->governor_enabled = true;
2064 else if (event == CPUFREQ_GOV_START)
2065 policy->governor_enabled = false;
2066 mutex_unlock(&cpufreq_governor_lock);
2069 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2070 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2071 module_put(policy->governor->owner);
2076 int cpufreq_register_governor(struct cpufreq_governor *governor)
2083 if (cpufreq_disabled())
2086 mutex_lock(&cpufreq_governor_mutex);
2088 governor->initialized = 0;
2090 if (!find_governor(governor->name)) {
2092 list_add(&governor->governor_list, &cpufreq_governor_list);
2095 mutex_unlock(&cpufreq_governor_mutex);
2098 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2100 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2102 struct cpufreq_policy *policy;
2103 unsigned long flags;
2108 if (cpufreq_disabled())
2111 /* clear last_governor for all inactive policies */
2112 read_lock_irqsave(&cpufreq_driver_lock, flags);
2113 for_each_inactive_policy(policy) {
2114 if (!strcmp(policy->last_governor, governor->name)) {
2115 policy->governor = NULL;
2116 strcpy(policy->last_governor, "\0");
2119 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2121 mutex_lock(&cpufreq_governor_mutex);
2122 list_del(&governor->governor_list);
2123 mutex_unlock(&cpufreq_governor_mutex);
2126 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2129 /*********************************************************************
2130 * POLICY INTERFACE *
2131 *********************************************************************/
2134 * cpufreq_get_policy - get the current cpufreq_policy
2135 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2138 * Reads the current cpufreq policy.
2140 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2142 struct cpufreq_policy *cpu_policy;
2146 cpu_policy = cpufreq_cpu_get(cpu);
2150 memcpy(policy, cpu_policy, sizeof(*policy));
2152 cpufreq_cpu_put(cpu_policy);
2155 EXPORT_SYMBOL(cpufreq_get_policy);
2158 * policy : current policy.
2159 * new_policy: policy to be set.
2161 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2162 struct cpufreq_policy *new_policy)
2164 struct cpufreq_governor *old_gov;
2167 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2168 new_policy->cpu, new_policy->min, new_policy->max);
2170 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2173 * This check works well when we store new min/max freq attributes,
2174 * because new_policy is a copy of policy with one field updated.
2176 if (new_policy->min > new_policy->max)
2179 /* verify the cpu speed can be set within this limit */
2180 ret = cpufreq_driver->verify(new_policy);
2184 /* adjust if necessary - all reasons */
2185 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2186 CPUFREQ_ADJUST, new_policy);
2189 * verify the cpu speed can be set within this limit, which might be
2190 * different to the first one
2192 ret = cpufreq_driver->verify(new_policy);
2196 /* notification of the new policy */
2197 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2198 CPUFREQ_NOTIFY, new_policy);
2200 policy->min = new_policy->min;
2201 policy->max = new_policy->max;
2203 pr_debug("new min and max freqs are %u - %u kHz\n",
2204 policy->min, policy->max);
2206 if (cpufreq_driver->setpolicy) {
2207 policy->policy = new_policy->policy;
2208 pr_debug("setting range\n");
2209 return cpufreq_driver->setpolicy(new_policy);
2212 if (new_policy->governor == policy->governor)
2215 pr_debug("governor switch\n");
2217 /* save old, working values */
2218 old_gov = policy->governor;
2219 /* end old governor */
2221 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2223 /* This can happen due to race with other operations */
2224 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2225 __func__, old_gov->name, ret);
2229 up_write(&policy->rwsem);
2230 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2231 down_write(&policy->rwsem);
2234 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2235 __func__, old_gov->name, ret);
2240 /* start new governor */
2241 policy->governor = new_policy->governor;
2242 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2244 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2248 up_write(&policy->rwsem);
2249 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2250 down_write(&policy->rwsem);
2253 /* new governor failed, so re-start old one */
2254 pr_debug("starting governor %s failed\n", policy->governor->name);
2256 policy->governor = old_gov;
2257 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2258 policy->governor = NULL;
2260 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2266 pr_debug("governor: change or update limits\n");
2267 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2271 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2272 * @cpu: CPU which shall be re-evaluated
2274 * Useful for policy notifiers which have different necessities
2275 * at different times.
2277 int cpufreq_update_policy(unsigned int cpu)
2279 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2280 struct cpufreq_policy new_policy;
2286 down_write(&policy->rwsem);
2288 pr_debug("updating policy for CPU %u\n", cpu);
2289 memcpy(&new_policy, policy, sizeof(*policy));
2290 new_policy.min = policy->user_policy.min;
2291 new_policy.max = policy->user_policy.max;
2294 * BIOS might change freq behind our back
2295 * -> ask driver for current freq and notify governors about a change
2297 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2298 new_policy.cur = cpufreq_driver->get(cpu);
2299 if (WARN_ON(!new_policy.cur)) {
2305 pr_debug("Driver did not initialize current freq\n");
2306 policy->cur = new_policy.cur;
2308 if (policy->cur != new_policy.cur && has_target())
2309 cpufreq_out_of_sync(policy, new_policy.cur);
2313 ret = cpufreq_set_policy(policy, &new_policy);
2316 up_write(&policy->rwsem);
2318 cpufreq_cpu_put(policy);
2321 EXPORT_SYMBOL(cpufreq_update_policy);
2323 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2324 unsigned long action, void *hcpu)
2326 unsigned int cpu = (unsigned long)hcpu;
2328 switch (action & ~CPU_TASKS_FROZEN) {
2330 cpufreq_online(cpu);
2333 case CPU_DOWN_PREPARE:
2334 cpufreq_offline_prepare(cpu);
2338 cpufreq_offline_finish(cpu);
2341 case CPU_DOWN_FAILED:
2342 cpufreq_online(cpu);
2348 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2349 .notifier_call = cpufreq_cpu_callback,
2352 /*********************************************************************
2354 *********************************************************************/
2355 static int cpufreq_boost_set_sw(int state)
2357 struct cpufreq_frequency_table *freq_table;
2358 struct cpufreq_policy *policy;
2361 for_each_active_policy(policy) {
2362 freq_table = cpufreq_frequency_get_table(policy->cpu);
2364 ret = cpufreq_frequency_table_cpuinfo(policy,
2367 pr_err("%s: Policy frequency update failed\n",
2371 policy->user_policy.max = policy->max;
2372 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2379 int cpufreq_boost_trigger_state(int state)
2381 unsigned long flags;
2384 if (cpufreq_driver->boost_enabled == state)
2387 write_lock_irqsave(&cpufreq_driver_lock, flags);
2388 cpufreq_driver->boost_enabled = state;
2389 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2391 ret = cpufreq_driver->set_boost(state);
2393 write_lock_irqsave(&cpufreq_driver_lock, flags);
2394 cpufreq_driver->boost_enabled = !state;
2395 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2397 pr_err("%s: Cannot %s BOOST\n",
2398 __func__, state ? "enable" : "disable");
2404 int cpufreq_boost_supported(void)
2406 if (likely(cpufreq_driver))
2407 return cpufreq_driver->boost_supported;
2411 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2413 static int create_boost_sysfs_file(void)
2417 if (!cpufreq_boost_supported())
2421 * Check if driver provides function to enable boost -
2422 * if not, use cpufreq_boost_set_sw as default
2424 if (!cpufreq_driver->set_boost)
2425 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2427 ret = cpufreq_sysfs_create_file(&boost.attr);
2429 pr_err("%s: cannot register global BOOST sysfs file\n",
2435 static void remove_boost_sysfs_file(void)
2437 if (cpufreq_boost_supported())
2438 cpufreq_sysfs_remove_file(&boost.attr);
2441 int cpufreq_enable_boost_support(void)
2443 if (!cpufreq_driver)
2446 if (cpufreq_boost_supported())
2449 cpufreq_driver->boost_supported = true;
2451 /* This will get removed on driver unregister */
2452 return create_boost_sysfs_file();
2454 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2456 int cpufreq_boost_enabled(void)
2458 return cpufreq_driver->boost_enabled;
2460 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2462 /*********************************************************************
2463 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2464 *********************************************************************/
2467 * cpufreq_register_driver - register a CPU Frequency driver
2468 * @driver_data: A struct cpufreq_driver containing the values#
2469 * submitted by the CPU Frequency driver.
2471 * Registers a CPU Frequency driver to this core code. This code
2472 * returns zero on success, -EBUSY when another driver got here first
2473 * (and isn't unregistered in the meantime).
2476 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2478 unsigned long flags;
2481 if (cpufreq_disabled())
2484 if (!driver_data || !driver_data->verify || !driver_data->init ||
2485 !(driver_data->setpolicy || driver_data->target_index ||
2486 driver_data->target) ||
2487 (driver_data->setpolicy && (driver_data->target_index ||
2488 driver_data->target)) ||
2489 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2492 pr_debug("trying to register driver %s\n", driver_data->name);
2494 /* Protect against concurrent CPU online/offline. */
2497 write_lock_irqsave(&cpufreq_driver_lock, flags);
2498 if (cpufreq_driver) {
2499 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2503 cpufreq_driver = driver_data;
2504 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2506 if (driver_data->setpolicy)
2507 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2509 ret = create_boost_sysfs_file();
2511 goto err_null_driver;
2513 ret = subsys_interface_register(&cpufreq_interface);
2515 goto err_boost_unreg;
2517 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2518 list_empty(&cpufreq_policy_list)) {
2519 /* if all ->init() calls failed, unregister */
2520 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2525 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2526 pr_debug("driver %s up and running\n", driver_data->name);
2533 subsys_interface_unregister(&cpufreq_interface);
2535 remove_boost_sysfs_file();
2537 write_lock_irqsave(&cpufreq_driver_lock, flags);
2538 cpufreq_driver = NULL;
2539 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2542 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2545 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2547 * Unregister the current CPUFreq driver. Only call this if you have
2548 * the right to do so, i.e. if you have succeeded in initialising before!
2549 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2550 * currently not initialised.
2552 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2554 unsigned long flags;
2556 if (!cpufreq_driver || (driver != cpufreq_driver))
2559 pr_debug("unregistering driver %s\n", driver->name);
2561 /* Protect against concurrent cpu hotplug */
2563 subsys_interface_unregister(&cpufreq_interface);
2564 remove_boost_sysfs_file();
2565 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2567 write_lock_irqsave(&cpufreq_driver_lock, flags);
2569 cpufreq_driver = NULL;
2571 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2576 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2579 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2580 * or mutexes when secondary CPUs are halted.
2582 static struct syscore_ops cpufreq_syscore_ops = {
2583 .shutdown = cpufreq_suspend,
2586 static int __init cpufreq_core_init(void)
2588 if (cpufreq_disabled())
2591 cpufreq_global_kobject = kobject_create();
2592 BUG_ON(!cpufreq_global_kobject);
2594 register_syscore_ops(&cpufreq_syscore_ops);
2598 core_initcall(cpufreq_core_init);