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);
677 policy->user_policy.policy = policy->policy;
678 policy->user_policy.governor = policy->governor;
683 * show_scaling_driver - show the cpufreq driver currently loaded
685 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
687 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
691 * show_scaling_available_governors - show the available CPUfreq governors
693 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
697 struct cpufreq_governor *t;
700 i += sprintf(buf, "performance powersave");
704 for_each_governor(t) {
705 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
706 - (CPUFREQ_NAME_LEN + 2)))
708 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
711 i += sprintf(&buf[i], "\n");
715 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
720 for_each_cpu(cpu, mask) {
722 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
723 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
724 if (i >= (PAGE_SIZE - 5))
727 i += sprintf(&buf[i], "\n");
730 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
733 * show_related_cpus - show the CPUs affected by each transition even if
734 * hw coordination is in use
736 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
738 return cpufreq_show_cpus(policy->related_cpus, buf);
742 * show_affected_cpus - show the CPUs affected by each transition
744 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
746 return cpufreq_show_cpus(policy->cpus, buf);
749 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
750 const char *buf, size_t count)
752 unsigned int freq = 0;
755 if (!policy->governor || !policy->governor->store_setspeed)
758 ret = sscanf(buf, "%u", &freq);
762 policy->governor->store_setspeed(policy, freq);
767 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
769 if (!policy->governor || !policy->governor->show_setspeed)
770 return sprintf(buf, "<unsupported>\n");
772 return policy->governor->show_setspeed(policy, buf);
776 * show_bios_limit - show the current cpufreq HW/BIOS limitation
778 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
782 if (cpufreq_driver->bios_limit) {
783 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
785 return sprintf(buf, "%u\n", limit);
787 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
790 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
791 cpufreq_freq_attr_ro(cpuinfo_min_freq);
792 cpufreq_freq_attr_ro(cpuinfo_max_freq);
793 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
794 cpufreq_freq_attr_ro(scaling_available_governors);
795 cpufreq_freq_attr_ro(scaling_driver);
796 cpufreq_freq_attr_ro(scaling_cur_freq);
797 cpufreq_freq_attr_ro(bios_limit);
798 cpufreq_freq_attr_ro(related_cpus);
799 cpufreq_freq_attr_ro(affected_cpus);
800 cpufreq_freq_attr_rw(scaling_min_freq);
801 cpufreq_freq_attr_rw(scaling_max_freq);
802 cpufreq_freq_attr_rw(scaling_governor);
803 cpufreq_freq_attr_rw(scaling_setspeed);
805 static struct attribute *default_attrs[] = {
806 &cpuinfo_min_freq.attr,
807 &cpuinfo_max_freq.attr,
808 &cpuinfo_transition_latency.attr,
809 &scaling_min_freq.attr,
810 &scaling_max_freq.attr,
813 &scaling_governor.attr,
814 &scaling_driver.attr,
815 &scaling_available_governors.attr,
816 &scaling_setspeed.attr,
820 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
821 #define to_attr(a) container_of(a, struct freq_attr, attr)
823 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
825 struct cpufreq_policy *policy = to_policy(kobj);
826 struct freq_attr *fattr = to_attr(attr);
829 down_read(&policy->rwsem);
832 ret = fattr->show(policy, buf);
836 up_read(&policy->rwsem);
841 static ssize_t store(struct kobject *kobj, struct attribute *attr,
842 const char *buf, size_t count)
844 struct cpufreq_policy *policy = to_policy(kobj);
845 struct freq_attr *fattr = to_attr(attr);
846 ssize_t ret = -EINVAL;
850 if (!cpu_online(policy->cpu))
853 down_write(&policy->rwsem);
855 /* Updating inactive policies is invalid, so avoid doing that. */
856 if (unlikely(policy_is_inactive(policy))) {
858 goto unlock_policy_rwsem;
862 ret = fattr->store(policy, buf, count);
867 up_write(&policy->rwsem);
874 static void cpufreq_sysfs_release(struct kobject *kobj)
876 struct cpufreq_policy *policy = to_policy(kobj);
877 pr_debug("last reference is dropped\n");
878 complete(&policy->kobj_unregister);
881 static const struct sysfs_ops sysfs_ops = {
886 static struct kobj_type ktype_cpufreq = {
887 .sysfs_ops = &sysfs_ops,
888 .default_attrs = default_attrs,
889 .release = cpufreq_sysfs_release,
892 struct kobject *cpufreq_global_kobject;
893 EXPORT_SYMBOL(cpufreq_global_kobject);
895 static int cpufreq_global_kobject_usage;
897 int cpufreq_get_global_kobject(void)
899 if (!cpufreq_global_kobject_usage++)
900 return kobject_add(cpufreq_global_kobject,
901 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
905 EXPORT_SYMBOL(cpufreq_get_global_kobject);
907 void cpufreq_put_global_kobject(void)
909 if (!--cpufreq_global_kobject_usage)
910 kobject_del(cpufreq_global_kobject);
912 EXPORT_SYMBOL(cpufreq_put_global_kobject);
914 int cpufreq_sysfs_create_file(const struct attribute *attr)
916 int ret = cpufreq_get_global_kobject();
919 ret = sysfs_create_file(cpufreq_global_kobject, attr);
921 cpufreq_put_global_kobject();
926 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
928 void cpufreq_sysfs_remove_file(const struct attribute *attr)
930 sysfs_remove_file(cpufreq_global_kobject, attr);
931 cpufreq_put_global_kobject();
933 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
935 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
937 struct device *cpu_dev;
939 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
944 cpu_dev = get_cpu_device(cpu);
945 if (WARN_ON(!cpu_dev))
948 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
951 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
953 struct device *cpu_dev;
955 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
957 cpu_dev = get_cpu_device(cpu);
958 if (WARN_ON(!cpu_dev))
961 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
964 /* Add/remove symlinks for all related CPUs */
965 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
970 /* Some related CPUs might not be present (physically hotplugged) */
971 for_each_cpu(j, policy->real_cpus) {
972 if (j == policy->kobj_cpu)
975 ret = add_cpu_dev_symlink(policy, j);
983 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
987 /* Some related CPUs might not be present (physically hotplugged) */
988 for_each_cpu(j, policy->real_cpus) {
989 if (j == policy->kobj_cpu)
992 remove_cpu_dev_symlink(policy, j);
996 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
998 struct freq_attr **drv_attr;
1001 /* set up files for this cpu device */
1002 drv_attr = cpufreq_driver->attr;
1003 while (drv_attr && *drv_attr) {
1004 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1009 if (cpufreq_driver->get) {
1010 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1015 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1019 if (cpufreq_driver->bios_limit) {
1020 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1025 return cpufreq_add_dev_symlink(policy);
1028 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1030 struct cpufreq_governor *gov = NULL;
1031 struct cpufreq_policy new_policy;
1033 memcpy(&new_policy, policy, sizeof(*policy));
1035 /* Update governor of new_policy to the governor used before hotplug */
1036 gov = find_governor(policy->last_governor);
1038 pr_debug("Restoring governor %s for cpu %d\n",
1039 policy->governor->name, policy->cpu);
1041 gov = CPUFREQ_DEFAULT_GOVERNOR;
1043 new_policy.governor = gov;
1045 /* Use the default policy if its valid. */
1046 if (cpufreq_driver->setpolicy)
1047 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
1049 /* set default policy */
1050 return cpufreq_set_policy(policy, &new_policy);
1053 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1057 /* Has this CPU been taken care of already? */
1058 if (cpumask_test_cpu(cpu, policy->cpus))
1062 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1064 pr_err("%s: Failed to stop governor\n", __func__);
1069 down_write(&policy->rwsem);
1070 cpumask_set_cpu(cpu, policy->cpus);
1071 up_write(&policy->rwsem);
1074 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1076 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1079 pr_err("%s: Failed to start governor\n", __func__);
1087 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1089 struct device *dev = get_cpu_device(cpu);
1090 struct cpufreq_policy *policy;
1096 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1100 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1101 goto err_free_policy;
1103 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1104 goto err_free_cpumask;
1106 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1107 goto err_free_rcpumask;
1109 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
1112 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1113 goto err_free_real_cpus;
1116 INIT_LIST_HEAD(&policy->policy_list);
1117 init_rwsem(&policy->rwsem);
1118 spin_lock_init(&policy->transition_lock);
1119 init_waitqueue_head(&policy->transition_wait);
1120 init_completion(&policy->kobj_unregister);
1121 INIT_WORK(&policy->update, handle_update);
1125 /* Set this once on allocation */
1126 policy->kobj_cpu = cpu;
1131 free_cpumask_var(policy->real_cpus);
1133 free_cpumask_var(policy->related_cpus);
1135 free_cpumask_var(policy->cpus);
1142 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1144 struct kobject *kobj;
1145 struct completion *cmp;
1148 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1149 CPUFREQ_REMOVE_POLICY, policy);
1151 down_write(&policy->rwsem);
1152 cpufreq_remove_dev_symlink(policy);
1153 kobj = &policy->kobj;
1154 cmp = &policy->kobj_unregister;
1155 up_write(&policy->rwsem);
1159 * We need to make sure that the underlying kobj is
1160 * actually not referenced anymore by anybody before we
1161 * proceed with unloading.
1163 pr_debug("waiting for dropping of refcount\n");
1164 wait_for_completion(cmp);
1165 pr_debug("wait complete\n");
1168 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1170 unsigned long flags;
1173 /* Remove policy from list */
1174 write_lock_irqsave(&cpufreq_driver_lock, flags);
1175 list_del(&policy->policy_list);
1177 for_each_cpu(cpu, policy->related_cpus)
1178 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1179 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1181 cpufreq_policy_put_kobj(policy, notify);
1182 free_cpumask_var(policy->real_cpus);
1183 free_cpumask_var(policy->related_cpus);
1184 free_cpumask_var(policy->cpus);
1188 static int cpufreq_online(unsigned int cpu)
1190 struct cpufreq_policy *policy;
1192 unsigned long flags;
1196 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1198 /* Check if this CPU already has a policy to manage it */
1199 policy = per_cpu(cpufreq_cpu_data, cpu);
1201 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1202 if (!policy_is_inactive(policy))
1203 return cpufreq_add_policy_cpu(policy, cpu);
1205 /* This is the only online CPU for the policy. Start over. */
1207 down_write(&policy->rwsem);
1209 policy->governor = NULL;
1210 up_write(&policy->rwsem);
1213 policy = cpufreq_policy_alloc(cpu);
1218 cpumask_copy(policy->cpus, cpumask_of(cpu));
1220 /* call driver. From then on the cpufreq must be able
1221 * to accept all calls to ->verify and ->setpolicy for this CPU
1223 ret = cpufreq_driver->init(policy);
1225 pr_debug("initialization failed\n");
1226 goto out_free_policy;
1229 down_write(&policy->rwsem);
1232 /* related_cpus should at least include policy->cpus. */
1233 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1234 /* Remember CPUs present at the policy creation time. */
1235 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1239 * affected cpus must always be the one, which are online. We aren't
1240 * managing offline cpus here.
1242 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1245 policy->user_policy.min = policy->min;
1246 policy->user_policy.max = policy->max;
1248 write_lock_irqsave(&cpufreq_driver_lock, flags);
1249 for_each_cpu(j, policy->related_cpus)
1250 per_cpu(cpufreq_cpu_data, j) = policy;
1251 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1254 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1255 policy->cur = cpufreq_driver->get(policy->cpu);
1257 pr_err("%s: ->get() failed\n", __func__);
1258 goto out_exit_policy;
1263 * Sometimes boot loaders set CPU frequency to a value outside of
1264 * frequency table present with cpufreq core. In such cases CPU might be
1265 * unstable if it has to run on that frequency for long duration of time
1266 * and so its better to set it to a frequency which is specified in
1267 * freq-table. This also makes cpufreq stats inconsistent as
1268 * cpufreq-stats would fail to register because current frequency of CPU
1269 * isn't found in freq-table.
1271 * Because we don't want this change to effect boot process badly, we go
1272 * for the next freq which is >= policy->cur ('cur' must be set by now,
1273 * otherwise we will end up setting freq to lowest of the table as 'cur'
1274 * is initialized to zero).
1276 * We are passing target-freq as "policy->cur - 1" otherwise
1277 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1278 * equal to target-freq.
1280 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1282 /* Are we running at unknown frequency ? */
1283 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1284 if (ret == -EINVAL) {
1285 /* Warn user and fix it */
1286 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1287 __func__, policy->cpu, policy->cur);
1288 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1289 CPUFREQ_RELATION_L);
1292 * Reaching here after boot in a few seconds may not
1293 * mean that system will remain stable at "unknown"
1294 * frequency for longer duration. Hence, a BUG_ON().
1297 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1298 __func__, policy->cpu, policy->cur);
1302 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1303 CPUFREQ_START, policy);
1306 ret = cpufreq_add_dev_interface(policy);
1308 goto out_exit_policy;
1309 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1310 CPUFREQ_CREATE_POLICY, policy);
1312 write_lock_irqsave(&cpufreq_driver_lock, flags);
1313 list_add(&policy->policy_list, &cpufreq_policy_list);
1314 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1317 ret = cpufreq_init_policy(policy);
1319 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1320 __func__, cpu, ret);
1321 /* cpufreq_policy_free() will notify based on this */
1323 goto out_exit_policy;
1327 policy->user_policy.policy = policy->policy;
1328 policy->user_policy.governor = policy->governor;
1330 up_write(&policy->rwsem);
1332 kobject_uevent(&policy->kobj, KOBJ_ADD);
1334 /* Callback for handling stuff after policy is ready */
1335 if (cpufreq_driver->ready)
1336 cpufreq_driver->ready(policy);
1338 pr_debug("initialization complete\n");
1343 up_write(&policy->rwsem);
1345 if (cpufreq_driver->exit)
1346 cpufreq_driver->exit(policy);
1348 cpufreq_policy_free(policy, !new_policy);
1353 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1355 * @sif: Subsystem interface structure pointer (not used)
1357 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1359 unsigned cpu = dev->id;
1362 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1364 if (cpu_online(cpu)) {
1365 ret = cpufreq_online(cpu);
1368 * A hotplug notifier will follow and we will handle it as CPU
1369 * online then. For now, just create the sysfs link, unless
1370 * there is no policy or the link is already present.
1372 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1374 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1375 ? add_cpu_dev_symlink(policy, cpu) : 0;
1381 static void cpufreq_offline_prepare(unsigned int cpu)
1383 struct cpufreq_policy *policy;
1385 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1387 policy = cpufreq_cpu_get_raw(cpu);
1389 pr_debug("%s: No cpu_data found\n", __func__);
1394 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1396 pr_err("%s: Failed to stop governor\n", __func__);
1399 down_write(&policy->rwsem);
1400 cpumask_clear_cpu(cpu, policy->cpus);
1402 if (policy_is_inactive(policy)) {
1404 strncpy(policy->last_governor, policy->governor->name,
1406 } else if (cpu == policy->cpu) {
1407 /* Nominate new CPU */
1408 policy->cpu = cpumask_any(policy->cpus);
1410 up_write(&policy->rwsem);
1412 /* Start governor again for active policy */
1413 if (!policy_is_inactive(policy)) {
1415 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1417 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1420 pr_err("%s: Failed to start governor\n", __func__);
1422 } else if (cpufreq_driver->stop_cpu) {
1423 cpufreq_driver->stop_cpu(policy);
1427 static void cpufreq_offline_finish(unsigned int cpu)
1429 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1432 pr_debug("%s: No cpu_data found\n", __func__);
1436 /* Only proceed for inactive policies */
1437 if (!policy_is_inactive(policy))
1440 /* If cpu is last user of policy, free policy */
1442 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1444 pr_err("%s: Failed to exit governor\n", __func__);
1448 * Perform the ->exit() even during light-weight tear-down,
1449 * since this is a core component, and is essential for the
1450 * subsequent light-weight ->init() to succeed.
1452 if (cpufreq_driver->exit)
1453 cpufreq_driver->exit(policy);
1457 * cpufreq_remove_dev - remove a CPU device
1459 * Removes the cpufreq interface for a CPU device.
1461 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1463 unsigned int cpu = dev->id;
1464 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1469 if (cpu_online(cpu)) {
1470 cpufreq_offline_prepare(cpu);
1471 cpufreq_offline_finish(cpu);
1474 cpumask_clear_cpu(cpu, policy->real_cpus);
1476 if (cpumask_empty(policy->real_cpus)) {
1477 cpufreq_policy_free(policy, true);
1481 if (cpu != policy->kobj_cpu) {
1482 remove_cpu_dev_symlink(policy, cpu);
1485 * The CPU owning the policy object is going away. Move it to
1486 * another suitable CPU.
1488 unsigned int new_cpu = cpumask_first(policy->real_cpus);
1489 struct device *new_dev = get_cpu_device(new_cpu);
1491 dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
1493 sysfs_remove_link(&new_dev->kobj, "cpufreq");
1494 policy->kobj_cpu = new_cpu;
1495 WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
1501 static void handle_update(struct work_struct *work)
1503 struct cpufreq_policy *policy =
1504 container_of(work, struct cpufreq_policy, update);
1505 unsigned int cpu = policy->cpu;
1506 pr_debug("handle_update for cpu %u called\n", cpu);
1507 cpufreq_update_policy(cpu);
1511 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1513 * @policy: policy managing CPUs
1514 * @new_freq: CPU frequency the CPU actually runs at
1516 * We adjust to current frequency first, and need to clean up later.
1517 * So either call to cpufreq_update_policy() or schedule handle_update()).
1519 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1520 unsigned int new_freq)
1522 struct cpufreq_freqs freqs;
1524 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1525 policy->cur, new_freq);
1527 freqs.old = policy->cur;
1528 freqs.new = new_freq;
1530 cpufreq_freq_transition_begin(policy, &freqs);
1531 cpufreq_freq_transition_end(policy, &freqs, 0);
1535 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1538 * This is the last known freq, without actually getting it from the driver.
1539 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1541 unsigned int cpufreq_quick_get(unsigned int cpu)
1543 struct cpufreq_policy *policy;
1544 unsigned int ret_freq = 0;
1546 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1547 return cpufreq_driver->get(cpu);
1549 policy = cpufreq_cpu_get(cpu);
1551 ret_freq = policy->cur;
1552 cpufreq_cpu_put(policy);
1557 EXPORT_SYMBOL(cpufreq_quick_get);
1560 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1563 * Just return the max possible frequency for a given CPU.
1565 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1567 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1568 unsigned int ret_freq = 0;
1571 ret_freq = policy->max;
1572 cpufreq_cpu_put(policy);
1577 EXPORT_SYMBOL(cpufreq_quick_get_max);
1579 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1581 unsigned int ret_freq = 0;
1583 if (!cpufreq_driver->get)
1586 ret_freq = cpufreq_driver->get(policy->cpu);
1588 /* Updating inactive policies is invalid, so avoid doing that. */
1589 if (unlikely(policy_is_inactive(policy)))
1592 if (ret_freq && policy->cur &&
1593 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1594 /* verify no discrepancy between actual and
1595 saved value exists */
1596 if (unlikely(ret_freq != policy->cur)) {
1597 cpufreq_out_of_sync(policy, ret_freq);
1598 schedule_work(&policy->update);
1606 * cpufreq_get - get the current CPU frequency (in kHz)
1609 * Get the CPU current (static) CPU frequency
1611 unsigned int cpufreq_get(unsigned int cpu)
1613 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1614 unsigned int ret_freq = 0;
1617 down_read(&policy->rwsem);
1618 ret_freq = __cpufreq_get(policy);
1619 up_read(&policy->rwsem);
1621 cpufreq_cpu_put(policy);
1626 EXPORT_SYMBOL(cpufreq_get);
1628 static struct subsys_interface cpufreq_interface = {
1630 .subsys = &cpu_subsys,
1631 .add_dev = cpufreq_add_dev,
1632 .remove_dev = cpufreq_remove_dev,
1636 * In case platform wants some specific frequency to be configured
1639 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1643 if (!policy->suspend_freq) {
1644 pr_err("%s: suspend_freq can't be zero\n", __func__);
1648 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1649 policy->suspend_freq);
1651 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1652 CPUFREQ_RELATION_H);
1654 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1655 __func__, policy->suspend_freq, ret);
1659 EXPORT_SYMBOL(cpufreq_generic_suspend);
1662 * cpufreq_suspend() - Suspend CPUFreq governors
1664 * Called during system wide Suspend/Hibernate cycles for suspending governors
1665 * as some platforms can't change frequency after this point in suspend cycle.
1666 * Because some of the devices (like: i2c, regulators, etc) they use for
1667 * changing frequency are suspended quickly after this point.
1669 void cpufreq_suspend(void)
1671 struct cpufreq_policy *policy;
1673 if (!cpufreq_driver)
1679 pr_debug("%s: Suspending Governors\n", __func__);
1681 for_each_active_policy(policy) {
1682 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1683 pr_err("%s: Failed to stop governor for policy: %p\n",
1685 else if (cpufreq_driver->suspend
1686 && cpufreq_driver->suspend(policy))
1687 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1692 cpufreq_suspended = true;
1696 * cpufreq_resume() - Resume CPUFreq governors
1698 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1699 * are suspended with cpufreq_suspend().
1701 void cpufreq_resume(void)
1703 struct cpufreq_policy *policy;
1705 if (!cpufreq_driver)
1708 cpufreq_suspended = false;
1713 pr_debug("%s: Resuming Governors\n", __func__);
1715 for_each_active_policy(policy) {
1716 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1717 pr_err("%s: Failed to resume driver: %p\n", __func__,
1719 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1720 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1721 pr_err("%s: Failed to start governor for policy: %p\n",
1726 * schedule call cpufreq_update_policy() for first-online CPU, as that
1727 * wouldn't be hotplugged-out on suspend. It will verify that the
1728 * current freq is in sync with what we believe it to be.
1730 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1731 if (WARN_ON(!policy))
1734 schedule_work(&policy->update);
1738 * cpufreq_get_current_driver - return current driver's name
1740 * Return the name string of the currently loaded cpufreq driver
1743 const char *cpufreq_get_current_driver(void)
1746 return cpufreq_driver->name;
1750 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1753 * cpufreq_get_driver_data - return current driver data
1755 * Return the private data of the currently loaded cpufreq
1756 * driver, or NULL if no cpufreq driver is loaded.
1758 void *cpufreq_get_driver_data(void)
1761 return cpufreq_driver->driver_data;
1765 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1767 /*********************************************************************
1768 * NOTIFIER LISTS INTERFACE *
1769 *********************************************************************/
1772 * cpufreq_register_notifier - register a driver with cpufreq
1773 * @nb: notifier function to register
1774 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1776 * Add a driver to one of two lists: either a list of drivers that
1777 * are notified about clock rate changes (once before and once after
1778 * the transition), or a list of drivers that are notified about
1779 * changes in cpufreq policy.
1781 * This function may sleep, and has the same return conditions as
1782 * blocking_notifier_chain_register.
1784 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1788 if (cpufreq_disabled())
1791 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1794 case CPUFREQ_TRANSITION_NOTIFIER:
1795 ret = srcu_notifier_chain_register(
1796 &cpufreq_transition_notifier_list, nb);
1798 case CPUFREQ_POLICY_NOTIFIER:
1799 ret = blocking_notifier_chain_register(
1800 &cpufreq_policy_notifier_list, nb);
1808 EXPORT_SYMBOL(cpufreq_register_notifier);
1811 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1812 * @nb: notifier block to be unregistered
1813 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1815 * Remove a driver from the CPU frequency notifier list.
1817 * This function may sleep, and has the same return conditions as
1818 * blocking_notifier_chain_unregister.
1820 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1824 if (cpufreq_disabled())
1828 case CPUFREQ_TRANSITION_NOTIFIER:
1829 ret = srcu_notifier_chain_unregister(
1830 &cpufreq_transition_notifier_list, nb);
1832 case CPUFREQ_POLICY_NOTIFIER:
1833 ret = blocking_notifier_chain_unregister(
1834 &cpufreq_policy_notifier_list, nb);
1842 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1845 /*********************************************************************
1847 *********************************************************************/
1849 /* Must set freqs->new to intermediate frequency */
1850 static int __target_intermediate(struct cpufreq_policy *policy,
1851 struct cpufreq_freqs *freqs, int index)
1855 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1857 /* We don't need to switch to intermediate freq */
1861 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1862 __func__, policy->cpu, freqs->old, freqs->new);
1864 cpufreq_freq_transition_begin(policy, freqs);
1865 ret = cpufreq_driver->target_intermediate(policy, index);
1866 cpufreq_freq_transition_end(policy, freqs, ret);
1869 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1875 static int __target_index(struct cpufreq_policy *policy,
1876 struct cpufreq_frequency_table *freq_table, int index)
1878 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1879 unsigned int intermediate_freq = 0;
1880 int retval = -EINVAL;
1883 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1885 /* Handle switching to intermediate frequency */
1886 if (cpufreq_driver->get_intermediate) {
1887 retval = __target_intermediate(policy, &freqs, index);
1891 intermediate_freq = freqs.new;
1892 /* Set old freq to intermediate */
1893 if (intermediate_freq)
1894 freqs.old = freqs.new;
1897 freqs.new = freq_table[index].frequency;
1898 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1899 __func__, policy->cpu, freqs.old, freqs.new);
1901 cpufreq_freq_transition_begin(policy, &freqs);
1904 retval = cpufreq_driver->target_index(policy, index);
1906 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1910 cpufreq_freq_transition_end(policy, &freqs, retval);
1913 * Failed after setting to intermediate freq? Driver should have
1914 * reverted back to initial frequency and so should we. Check
1915 * here for intermediate_freq instead of get_intermediate, in
1916 * case we haven't switched to intermediate freq at all.
1918 if (unlikely(retval && intermediate_freq)) {
1919 freqs.old = intermediate_freq;
1920 freqs.new = policy->restore_freq;
1921 cpufreq_freq_transition_begin(policy, &freqs);
1922 cpufreq_freq_transition_end(policy, &freqs, 0);
1929 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1930 unsigned int target_freq,
1931 unsigned int relation)
1933 unsigned int old_target_freq = target_freq;
1934 int retval = -EINVAL;
1936 if (cpufreq_disabled())
1939 /* Make sure that target_freq is within supported range */
1940 if (target_freq > policy->max)
1941 target_freq = policy->max;
1942 if (target_freq < policy->min)
1943 target_freq = policy->min;
1945 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1946 policy->cpu, target_freq, relation, old_target_freq);
1949 * This might look like a redundant call as we are checking it again
1950 * after finding index. But it is left intentionally for cases where
1951 * exactly same freq is called again and so we can save on few function
1954 if (target_freq == policy->cur)
1957 /* Save last value to restore later on errors */
1958 policy->restore_freq = policy->cur;
1960 if (cpufreq_driver->target)
1961 retval = cpufreq_driver->target(policy, target_freq, relation);
1962 else if (cpufreq_driver->target_index) {
1963 struct cpufreq_frequency_table *freq_table;
1966 freq_table = cpufreq_frequency_get_table(policy->cpu);
1967 if (unlikely(!freq_table)) {
1968 pr_err("%s: Unable to find freq_table\n", __func__);
1972 retval = cpufreq_frequency_table_target(policy, freq_table,
1973 target_freq, relation, &index);
1974 if (unlikely(retval)) {
1975 pr_err("%s: Unable to find matching freq\n", __func__);
1979 if (freq_table[index].frequency == policy->cur) {
1984 retval = __target_index(policy, freq_table, index);
1990 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1992 int cpufreq_driver_target(struct cpufreq_policy *policy,
1993 unsigned int target_freq,
1994 unsigned int relation)
1998 down_write(&policy->rwsem);
2000 ret = __cpufreq_driver_target(policy, target_freq, relation);
2002 up_write(&policy->rwsem);
2006 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2008 static int __cpufreq_governor(struct cpufreq_policy *policy,
2013 /* Only must be defined when default governor is known to have latency
2014 restrictions, like e.g. conservative or ondemand.
2015 That this is the case is already ensured in Kconfig
2017 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2018 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2020 struct cpufreq_governor *gov = NULL;
2023 /* Don't start any governor operations if we are entering suspend */
2024 if (cpufreq_suspended)
2027 * Governor might not be initiated here if ACPI _PPC changed
2028 * notification happened, so check it.
2030 if (!policy->governor)
2033 if (policy->governor->max_transition_latency &&
2034 policy->cpuinfo.transition_latency >
2035 policy->governor->max_transition_latency) {
2039 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2040 policy->governor->name, gov->name);
2041 policy->governor = gov;
2045 if (event == CPUFREQ_GOV_POLICY_INIT)
2046 if (!try_module_get(policy->governor->owner))
2049 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2050 policy->cpu, event);
2052 mutex_lock(&cpufreq_governor_lock);
2053 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2054 || (!policy->governor_enabled
2055 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2056 mutex_unlock(&cpufreq_governor_lock);
2060 if (event == CPUFREQ_GOV_STOP)
2061 policy->governor_enabled = false;
2062 else if (event == CPUFREQ_GOV_START)
2063 policy->governor_enabled = true;
2065 mutex_unlock(&cpufreq_governor_lock);
2067 ret = policy->governor->governor(policy, event);
2070 if (event == CPUFREQ_GOV_POLICY_INIT)
2071 policy->governor->initialized++;
2072 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2073 policy->governor->initialized--;
2075 /* Restore original values */
2076 mutex_lock(&cpufreq_governor_lock);
2077 if (event == CPUFREQ_GOV_STOP)
2078 policy->governor_enabled = true;
2079 else if (event == CPUFREQ_GOV_START)
2080 policy->governor_enabled = false;
2081 mutex_unlock(&cpufreq_governor_lock);
2084 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2085 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2086 module_put(policy->governor->owner);
2091 int cpufreq_register_governor(struct cpufreq_governor *governor)
2098 if (cpufreq_disabled())
2101 mutex_lock(&cpufreq_governor_mutex);
2103 governor->initialized = 0;
2105 if (!find_governor(governor->name)) {
2107 list_add(&governor->governor_list, &cpufreq_governor_list);
2110 mutex_unlock(&cpufreq_governor_mutex);
2113 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2115 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2117 struct cpufreq_policy *policy;
2118 unsigned long flags;
2123 if (cpufreq_disabled())
2126 /* clear last_governor for all inactive policies */
2127 read_lock_irqsave(&cpufreq_driver_lock, flags);
2128 for_each_inactive_policy(policy) {
2129 if (!strcmp(policy->last_governor, governor->name)) {
2130 policy->governor = NULL;
2131 strcpy(policy->last_governor, "\0");
2134 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2136 mutex_lock(&cpufreq_governor_mutex);
2137 list_del(&governor->governor_list);
2138 mutex_unlock(&cpufreq_governor_mutex);
2141 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2144 /*********************************************************************
2145 * POLICY INTERFACE *
2146 *********************************************************************/
2149 * cpufreq_get_policy - get the current cpufreq_policy
2150 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2153 * Reads the current cpufreq policy.
2155 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2157 struct cpufreq_policy *cpu_policy;
2161 cpu_policy = cpufreq_cpu_get(cpu);
2165 memcpy(policy, cpu_policy, sizeof(*policy));
2167 cpufreq_cpu_put(cpu_policy);
2170 EXPORT_SYMBOL(cpufreq_get_policy);
2173 * policy : current policy.
2174 * new_policy: policy to be set.
2176 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2177 struct cpufreq_policy *new_policy)
2179 struct cpufreq_governor *old_gov;
2182 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2183 new_policy->cpu, new_policy->min, new_policy->max);
2185 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2188 * This check works well when we store new min/max freq attributes,
2189 * because new_policy is a copy of policy with one field updated.
2191 if (new_policy->min > new_policy->max)
2194 /* verify the cpu speed can be set within this limit */
2195 ret = cpufreq_driver->verify(new_policy);
2199 /* adjust if necessary - all reasons */
2200 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2201 CPUFREQ_ADJUST, new_policy);
2204 * verify the cpu speed can be set within this limit, which might be
2205 * different to the first one
2207 ret = cpufreq_driver->verify(new_policy);
2211 /* notification of the new policy */
2212 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2213 CPUFREQ_NOTIFY, new_policy);
2215 policy->min = new_policy->min;
2216 policy->max = new_policy->max;
2218 pr_debug("new min and max freqs are %u - %u kHz\n",
2219 policy->min, policy->max);
2221 if (cpufreq_driver->setpolicy) {
2222 policy->policy = new_policy->policy;
2223 pr_debug("setting range\n");
2224 return cpufreq_driver->setpolicy(new_policy);
2227 if (new_policy->governor == policy->governor)
2230 pr_debug("governor switch\n");
2232 /* save old, working values */
2233 old_gov = policy->governor;
2234 /* end old governor */
2236 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2238 /* This can happen due to race with other operations */
2239 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2240 __func__, old_gov->name, ret);
2244 up_write(&policy->rwsem);
2245 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2246 down_write(&policy->rwsem);
2249 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2250 __func__, old_gov->name, ret);
2255 /* start new governor */
2256 policy->governor = new_policy->governor;
2257 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2259 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2263 up_write(&policy->rwsem);
2264 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2265 down_write(&policy->rwsem);
2268 /* new governor failed, so re-start old one */
2269 pr_debug("starting governor %s failed\n", policy->governor->name);
2271 policy->governor = old_gov;
2272 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2273 policy->governor = NULL;
2275 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2281 pr_debug("governor: change or update limits\n");
2282 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2286 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2287 * @cpu: CPU which shall be re-evaluated
2289 * Useful for policy notifiers which have different necessities
2290 * at different times.
2292 int cpufreq_update_policy(unsigned int cpu)
2294 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2295 struct cpufreq_policy new_policy;
2301 down_write(&policy->rwsem);
2303 pr_debug("updating policy for CPU %u\n", cpu);
2304 memcpy(&new_policy, policy, sizeof(*policy));
2305 new_policy.min = policy->user_policy.min;
2306 new_policy.max = policy->user_policy.max;
2307 new_policy.policy = policy->user_policy.policy;
2308 new_policy.governor = policy->user_policy.governor;
2311 * BIOS might change freq behind our back
2312 * -> ask driver for current freq and notify governors about a change
2314 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2315 new_policy.cur = cpufreq_driver->get(cpu);
2316 if (WARN_ON(!new_policy.cur)) {
2322 pr_debug("Driver did not initialize current freq\n");
2323 policy->cur = new_policy.cur;
2325 if (policy->cur != new_policy.cur && has_target())
2326 cpufreq_out_of_sync(policy, new_policy.cur);
2330 ret = cpufreq_set_policy(policy, &new_policy);
2333 up_write(&policy->rwsem);
2335 cpufreq_cpu_put(policy);
2338 EXPORT_SYMBOL(cpufreq_update_policy);
2340 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2341 unsigned long action, void *hcpu)
2343 unsigned int cpu = (unsigned long)hcpu;
2345 switch (action & ~CPU_TASKS_FROZEN) {
2347 cpufreq_online(cpu);
2350 case CPU_DOWN_PREPARE:
2351 cpufreq_offline_prepare(cpu);
2355 cpufreq_offline_finish(cpu);
2358 case CPU_DOWN_FAILED:
2359 cpufreq_online(cpu);
2365 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2366 .notifier_call = cpufreq_cpu_callback,
2369 /*********************************************************************
2371 *********************************************************************/
2372 static int cpufreq_boost_set_sw(int state)
2374 struct cpufreq_frequency_table *freq_table;
2375 struct cpufreq_policy *policy;
2378 for_each_active_policy(policy) {
2379 freq_table = cpufreq_frequency_get_table(policy->cpu);
2381 ret = cpufreq_frequency_table_cpuinfo(policy,
2384 pr_err("%s: Policy frequency update failed\n",
2388 policy->user_policy.max = policy->max;
2389 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2396 int cpufreq_boost_trigger_state(int state)
2398 unsigned long flags;
2401 if (cpufreq_driver->boost_enabled == state)
2404 write_lock_irqsave(&cpufreq_driver_lock, flags);
2405 cpufreq_driver->boost_enabled = state;
2406 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2408 ret = cpufreq_driver->set_boost(state);
2410 write_lock_irqsave(&cpufreq_driver_lock, flags);
2411 cpufreq_driver->boost_enabled = !state;
2412 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2414 pr_err("%s: Cannot %s BOOST\n",
2415 __func__, state ? "enable" : "disable");
2421 int cpufreq_boost_supported(void)
2423 if (likely(cpufreq_driver))
2424 return cpufreq_driver->boost_supported;
2428 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2430 int cpufreq_boost_enabled(void)
2432 return cpufreq_driver->boost_enabled;
2434 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2436 /*********************************************************************
2437 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2438 *********************************************************************/
2441 * cpufreq_register_driver - register a CPU Frequency driver
2442 * @driver_data: A struct cpufreq_driver containing the values#
2443 * submitted by the CPU Frequency driver.
2445 * Registers a CPU Frequency driver to this core code. This code
2446 * returns zero on success, -EBUSY when another driver got here first
2447 * (and isn't unregistered in the meantime).
2450 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2452 unsigned long flags;
2455 if (cpufreq_disabled())
2458 if (!driver_data || !driver_data->verify || !driver_data->init ||
2459 !(driver_data->setpolicy || driver_data->target_index ||
2460 driver_data->target) ||
2461 (driver_data->setpolicy && (driver_data->target_index ||
2462 driver_data->target)) ||
2463 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2466 pr_debug("trying to register driver %s\n", driver_data->name);
2468 /* Protect against concurrent CPU online/offline. */
2471 write_lock_irqsave(&cpufreq_driver_lock, flags);
2472 if (cpufreq_driver) {
2473 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2477 cpufreq_driver = driver_data;
2478 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2480 if (driver_data->setpolicy)
2481 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2483 if (cpufreq_boost_supported()) {
2485 * Check if driver provides function to enable boost -
2486 * if not, use cpufreq_boost_set_sw as default
2488 if (!cpufreq_driver->set_boost)
2489 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2491 ret = cpufreq_sysfs_create_file(&boost.attr);
2493 pr_err("%s: cannot register global BOOST sysfs file\n",
2495 goto err_null_driver;
2499 ret = subsys_interface_register(&cpufreq_interface);
2501 goto err_boost_unreg;
2503 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2504 list_empty(&cpufreq_policy_list)) {
2505 /* if all ->init() calls failed, unregister */
2506 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2511 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2512 pr_debug("driver %s up and running\n", driver_data->name);
2519 subsys_interface_unregister(&cpufreq_interface);
2521 if (cpufreq_boost_supported())
2522 cpufreq_sysfs_remove_file(&boost.attr);
2524 write_lock_irqsave(&cpufreq_driver_lock, flags);
2525 cpufreq_driver = NULL;
2526 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2529 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2532 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2534 * Unregister the current CPUFreq driver. Only call this if you have
2535 * the right to do so, i.e. if you have succeeded in initialising before!
2536 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2537 * currently not initialised.
2539 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2541 unsigned long flags;
2543 if (!cpufreq_driver || (driver != cpufreq_driver))
2546 pr_debug("unregistering driver %s\n", driver->name);
2548 /* Protect against concurrent cpu hotplug */
2550 subsys_interface_unregister(&cpufreq_interface);
2551 if (cpufreq_boost_supported())
2552 cpufreq_sysfs_remove_file(&boost.attr);
2554 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2556 write_lock_irqsave(&cpufreq_driver_lock, flags);
2558 cpufreq_driver = NULL;
2560 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2565 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2568 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2569 * or mutexes when secondary CPUs are halted.
2571 static struct syscore_ops cpufreq_syscore_ops = {
2572 .shutdown = cpufreq_suspend,
2575 static int __init cpufreq_core_init(void)
2577 if (cpufreq_disabled())
2580 cpufreq_global_kobject = kobject_create();
2581 BUG_ON(!cpufreq_global_kobject);
2583 register_syscore_ops(&cpufreq_syscore_ops);
2587 core_initcall(cpufreq_core_init);