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 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
613 ret = sscanf(buf, "%u", &new_policy.object); \
617 temp = new_policy.object; \
618 ret = cpufreq_set_policy(policy, &new_policy); \
620 policy->user_policy.object = temp; \
622 return ret ? ret : count; \
625 store_one(scaling_min_freq, min);
626 store_one(scaling_max_freq, max);
629 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
631 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
634 unsigned int cur_freq = __cpufreq_get(policy);
636 return sprintf(buf, "<unknown>");
637 return sprintf(buf, "%u\n", cur_freq);
641 * show_scaling_governor - show the current policy for the specified CPU
643 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
645 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
646 return sprintf(buf, "powersave\n");
647 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
648 return sprintf(buf, "performance\n");
649 else if (policy->governor)
650 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
651 policy->governor->name);
656 * store_scaling_governor - store policy for the specified CPU
658 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
659 const char *buf, size_t count)
662 char str_governor[16];
663 struct cpufreq_policy new_policy;
665 ret = cpufreq_get_policy(&new_policy, policy->cpu);
669 ret = sscanf(buf, "%15s", str_governor);
673 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
674 &new_policy.governor))
677 ret = cpufreq_set_policy(policy, &new_policy);
679 policy->user_policy.policy = policy->policy;
680 policy->user_policy.governor = policy->governor;
689 * show_scaling_driver - show the cpufreq driver currently loaded
691 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
693 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
697 * show_scaling_available_governors - show the available CPUfreq governors
699 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
703 struct cpufreq_governor *t;
706 i += sprintf(buf, "performance powersave");
710 for_each_governor(t) {
711 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
712 - (CPUFREQ_NAME_LEN + 2)))
714 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
717 i += sprintf(&buf[i], "\n");
721 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
726 for_each_cpu(cpu, mask) {
728 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
729 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
730 if (i >= (PAGE_SIZE - 5))
733 i += sprintf(&buf[i], "\n");
736 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
739 * show_related_cpus - show the CPUs affected by each transition even if
740 * hw coordination is in use
742 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
744 return cpufreq_show_cpus(policy->related_cpus, buf);
748 * show_affected_cpus - show the CPUs affected by each transition
750 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
752 return cpufreq_show_cpus(policy->cpus, buf);
755 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
756 const char *buf, size_t count)
758 unsigned int freq = 0;
761 if (!policy->governor || !policy->governor->store_setspeed)
764 ret = sscanf(buf, "%u", &freq);
768 policy->governor->store_setspeed(policy, freq);
773 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
775 if (!policy->governor || !policy->governor->show_setspeed)
776 return sprintf(buf, "<unsupported>\n");
778 return policy->governor->show_setspeed(policy, buf);
782 * show_bios_limit - show the current cpufreq HW/BIOS limitation
784 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
788 if (cpufreq_driver->bios_limit) {
789 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
791 return sprintf(buf, "%u\n", limit);
793 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
796 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
797 cpufreq_freq_attr_ro(cpuinfo_min_freq);
798 cpufreq_freq_attr_ro(cpuinfo_max_freq);
799 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
800 cpufreq_freq_attr_ro(scaling_available_governors);
801 cpufreq_freq_attr_ro(scaling_driver);
802 cpufreq_freq_attr_ro(scaling_cur_freq);
803 cpufreq_freq_attr_ro(bios_limit);
804 cpufreq_freq_attr_ro(related_cpus);
805 cpufreq_freq_attr_ro(affected_cpus);
806 cpufreq_freq_attr_rw(scaling_min_freq);
807 cpufreq_freq_attr_rw(scaling_max_freq);
808 cpufreq_freq_attr_rw(scaling_governor);
809 cpufreq_freq_attr_rw(scaling_setspeed);
811 static struct attribute *default_attrs[] = {
812 &cpuinfo_min_freq.attr,
813 &cpuinfo_max_freq.attr,
814 &cpuinfo_transition_latency.attr,
815 &scaling_min_freq.attr,
816 &scaling_max_freq.attr,
819 &scaling_governor.attr,
820 &scaling_driver.attr,
821 &scaling_available_governors.attr,
822 &scaling_setspeed.attr,
826 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
827 #define to_attr(a) container_of(a, struct freq_attr, attr)
829 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
831 struct cpufreq_policy *policy = to_policy(kobj);
832 struct freq_attr *fattr = to_attr(attr);
835 down_read(&policy->rwsem);
838 ret = fattr->show(policy, buf);
842 up_read(&policy->rwsem);
847 static ssize_t store(struct kobject *kobj, struct attribute *attr,
848 const char *buf, size_t count)
850 struct cpufreq_policy *policy = to_policy(kobj);
851 struct freq_attr *fattr = to_attr(attr);
852 ssize_t ret = -EINVAL;
856 if (!cpu_online(policy->cpu))
859 down_write(&policy->rwsem);
861 /* Updating inactive policies is invalid, so avoid doing that. */
862 if (unlikely(policy_is_inactive(policy))) {
864 goto unlock_policy_rwsem;
868 ret = fattr->store(policy, buf, count);
873 up_write(&policy->rwsem);
880 static void cpufreq_sysfs_release(struct kobject *kobj)
882 struct cpufreq_policy *policy = to_policy(kobj);
883 pr_debug("last reference is dropped\n");
884 complete(&policy->kobj_unregister);
887 static const struct sysfs_ops sysfs_ops = {
892 static struct kobj_type ktype_cpufreq = {
893 .sysfs_ops = &sysfs_ops,
894 .default_attrs = default_attrs,
895 .release = cpufreq_sysfs_release,
898 struct kobject *cpufreq_global_kobject;
899 EXPORT_SYMBOL(cpufreq_global_kobject);
901 static int cpufreq_global_kobject_usage;
903 int cpufreq_get_global_kobject(void)
905 if (!cpufreq_global_kobject_usage++)
906 return kobject_add(cpufreq_global_kobject,
907 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
911 EXPORT_SYMBOL(cpufreq_get_global_kobject);
913 void cpufreq_put_global_kobject(void)
915 if (!--cpufreq_global_kobject_usage)
916 kobject_del(cpufreq_global_kobject);
918 EXPORT_SYMBOL(cpufreq_put_global_kobject);
920 int cpufreq_sysfs_create_file(const struct attribute *attr)
922 int ret = cpufreq_get_global_kobject();
925 ret = sysfs_create_file(cpufreq_global_kobject, attr);
927 cpufreq_put_global_kobject();
932 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
934 void cpufreq_sysfs_remove_file(const struct attribute *attr)
936 sysfs_remove_file(cpufreq_global_kobject, attr);
937 cpufreq_put_global_kobject();
939 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
941 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
943 struct device *cpu_dev;
945 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
950 cpu_dev = get_cpu_device(cpu);
951 if (WARN_ON(!cpu_dev))
954 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
957 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
959 struct device *cpu_dev;
961 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
963 cpu_dev = get_cpu_device(cpu);
964 if (WARN_ON(!cpu_dev))
967 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
970 /* Add/remove symlinks for all related CPUs */
971 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
976 /* Some related CPUs might not be present (physically hotplugged) */
977 for_each_cpu(j, policy->real_cpus) {
978 if (j == policy->kobj_cpu)
981 ret = add_cpu_dev_symlink(policy, j);
989 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
993 /* Some related CPUs might not be present (physically hotplugged) */
994 for_each_cpu(j, policy->real_cpus) {
995 if (j == policy->kobj_cpu)
998 remove_cpu_dev_symlink(policy, j);
1002 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1004 struct freq_attr **drv_attr;
1007 /* set up files for this cpu device */
1008 drv_attr = cpufreq_driver->attr;
1009 while (drv_attr && *drv_attr) {
1010 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1015 if (cpufreq_driver->get) {
1016 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1021 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1025 if (cpufreq_driver->bios_limit) {
1026 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1031 return cpufreq_add_dev_symlink(policy);
1034 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1036 struct cpufreq_governor *gov = NULL;
1037 struct cpufreq_policy new_policy;
1039 memcpy(&new_policy, policy, sizeof(*policy));
1041 /* Update governor of new_policy to the governor used before hotplug */
1042 gov = find_governor(policy->last_governor);
1044 pr_debug("Restoring governor %s for cpu %d\n",
1045 policy->governor->name, policy->cpu);
1047 gov = CPUFREQ_DEFAULT_GOVERNOR;
1049 new_policy.governor = gov;
1051 /* Use the default policy if its valid. */
1052 if (cpufreq_driver->setpolicy)
1053 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
1055 /* set default policy */
1056 return cpufreq_set_policy(policy, &new_policy);
1059 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1063 /* Has this CPU been taken care of already? */
1064 if (cpumask_test_cpu(cpu, policy->cpus))
1068 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1070 pr_err("%s: Failed to stop governor\n", __func__);
1075 down_write(&policy->rwsem);
1076 cpumask_set_cpu(cpu, policy->cpus);
1077 up_write(&policy->rwsem);
1080 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1082 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1085 pr_err("%s: Failed to start governor\n", __func__);
1093 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1095 struct device *dev = get_cpu_device(cpu);
1096 struct cpufreq_policy *policy;
1102 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1106 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1107 goto err_free_policy;
1109 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1110 goto err_free_cpumask;
1112 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1113 goto err_free_rcpumask;
1115 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
1118 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1119 goto err_free_real_cpus;
1122 INIT_LIST_HEAD(&policy->policy_list);
1123 init_rwsem(&policy->rwsem);
1124 spin_lock_init(&policy->transition_lock);
1125 init_waitqueue_head(&policy->transition_wait);
1126 init_completion(&policy->kobj_unregister);
1127 INIT_WORK(&policy->update, handle_update);
1131 /* Set this once on allocation */
1132 policy->kobj_cpu = cpu;
1137 free_cpumask_var(policy->real_cpus);
1139 free_cpumask_var(policy->related_cpus);
1141 free_cpumask_var(policy->cpus);
1148 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1150 struct kobject *kobj;
1151 struct completion *cmp;
1154 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1155 CPUFREQ_REMOVE_POLICY, policy);
1157 down_write(&policy->rwsem);
1158 cpufreq_remove_dev_symlink(policy);
1159 kobj = &policy->kobj;
1160 cmp = &policy->kobj_unregister;
1161 up_write(&policy->rwsem);
1165 * We need to make sure that the underlying kobj is
1166 * actually not referenced anymore by anybody before we
1167 * proceed with unloading.
1169 pr_debug("waiting for dropping of refcount\n");
1170 wait_for_completion(cmp);
1171 pr_debug("wait complete\n");
1174 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1176 unsigned long flags;
1179 /* Remove policy from list */
1180 write_lock_irqsave(&cpufreq_driver_lock, flags);
1181 list_del(&policy->policy_list);
1183 for_each_cpu(cpu, policy->related_cpus)
1184 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1185 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1187 cpufreq_policy_put_kobj(policy, notify);
1188 free_cpumask_var(policy->real_cpus);
1189 free_cpumask_var(policy->related_cpus);
1190 free_cpumask_var(policy->cpus);
1195 * cpufreq_add_dev - add a CPU device
1197 * Adds the cpufreq interface for a CPU device.
1199 * The Oracle says: try running cpufreq registration/unregistration concurrently
1200 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1201 * mess up, but more thorough testing is needed. - Mathieu
1203 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1205 unsigned int j, cpu = dev->id;
1207 struct cpufreq_policy *policy;
1208 unsigned long flags;
1209 bool recover_policy;
1211 pr_debug("adding CPU %u\n", cpu);
1213 if (cpu_is_offline(cpu)) {
1215 * Only possible if we are here from the subsys_interface add
1216 * callback. A hotplug notifier will follow and we will handle
1217 * it as CPU online then. For now, just create the sysfs link,
1218 * unless there is no policy or the link is already present.
1220 policy = per_cpu(cpufreq_cpu_data, cpu);
1221 return policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1222 ? add_cpu_dev_symlink(policy, cpu) : 0;
1225 /* Check if this CPU already has a policy to manage it */
1226 policy = per_cpu(cpufreq_cpu_data, cpu);
1228 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1229 if (!policy_is_inactive(policy))
1230 return cpufreq_add_policy_cpu(policy, cpu);
1232 /* This is the only online CPU for the policy. Start over. */
1233 recover_policy = true;
1234 down_write(&policy->rwsem);
1236 policy->governor = NULL;
1237 up_write(&policy->rwsem);
1239 recover_policy = false;
1240 policy = cpufreq_policy_alloc(cpu);
1245 cpumask_copy(policy->cpus, cpumask_of(cpu));
1247 /* call driver. From then on the cpufreq must be able
1248 * to accept all calls to ->verify and ->setpolicy for this CPU
1250 ret = cpufreq_driver->init(policy);
1252 pr_debug("initialization failed\n");
1253 goto out_free_policy;
1256 down_write(&policy->rwsem);
1258 if (!recover_policy) {
1259 /* related_cpus should at least include policy->cpus. */
1260 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1261 /* Remember CPUs present at the policy creation time. */
1262 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1266 * affected cpus must always be the one, which are online. We aren't
1267 * managing offline cpus here.
1269 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1271 if (!recover_policy) {
1272 policy->user_policy.min = policy->min;
1273 policy->user_policy.max = policy->max;
1275 write_lock_irqsave(&cpufreq_driver_lock, flags);
1276 for_each_cpu(j, policy->related_cpus)
1277 per_cpu(cpufreq_cpu_data, j) = policy;
1278 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1281 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1282 policy->cur = cpufreq_driver->get(policy->cpu);
1284 pr_err("%s: ->get() failed\n", __func__);
1285 goto out_exit_policy;
1290 * Sometimes boot loaders set CPU frequency to a value outside of
1291 * frequency table present with cpufreq core. In such cases CPU might be
1292 * unstable if it has to run on that frequency for long duration of time
1293 * and so its better to set it to a frequency which is specified in
1294 * freq-table. This also makes cpufreq stats inconsistent as
1295 * cpufreq-stats would fail to register because current frequency of CPU
1296 * isn't found in freq-table.
1298 * Because we don't want this change to effect boot process badly, we go
1299 * for the next freq which is >= policy->cur ('cur' must be set by now,
1300 * otherwise we will end up setting freq to lowest of the table as 'cur'
1301 * is initialized to zero).
1303 * We are passing target-freq as "policy->cur - 1" otherwise
1304 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1305 * equal to target-freq.
1307 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1309 /* Are we running at unknown frequency ? */
1310 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1311 if (ret == -EINVAL) {
1312 /* Warn user and fix it */
1313 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1314 __func__, policy->cpu, policy->cur);
1315 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1316 CPUFREQ_RELATION_L);
1319 * Reaching here after boot in a few seconds may not
1320 * mean that system will remain stable at "unknown"
1321 * frequency for longer duration. Hence, a BUG_ON().
1324 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1325 __func__, policy->cpu, policy->cur);
1329 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1330 CPUFREQ_START, policy);
1332 if (!recover_policy) {
1333 ret = cpufreq_add_dev_interface(policy);
1335 goto out_exit_policy;
1336 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1337 CPUFREQ_CREATE_POLICY, policy);
1339 write_lock_irqsave(&cpufreq_driver_lock, flags);
1340 list_add(&policy->policy_list, &cpufreq_policy_list);
1341 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1344 ret = cpufreq_init_policy(policy);
1346 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1347 __func__, cpu, ret);
1348 goto out_remove_policy_notify;
1351 if (!recover_policy) {
1352 policy->user_policy.policy = policy->policy;
1353 policy->user_policy.governor = policy->governor;
1355 up_write(&policy->rwsem);
1357 kobject_uevent(&policy->kobj, KOBJ_ADD);
1359 /* Callback for handling stuff after policy is ready */
1360 if (cpufreq_driver->ready)
1361 cpufreq_driver->ready(policy);
1363 pr_debug("initialization complete\n");
1367 out_remove_policy_notify:
1368 /* cpufreq_policy_free() will notify based on this */
1369 recover_policy = true;
1371 up_write(&policy->rwsem);
1373 if (cpufreq_driver->exit)
1374 cpufreq_driver->exit(policy);
1376 cpufreq_policy_free(policy, recover_policy);
1380 static void cpufreq_offline_prepare(unsigned int cpu)
1382 struct cpufreq_policy *policy;
1384 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1386 policy = cpufreq_cpu_get_raw(cpu);
1388 pr_debug("%s: No cpu_data found\n", __func__);
1393 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1395 pr_err("%s: Failed to stop governor\n", __func__);
1398 down_write(&policy->rwsem);
1399 cpumask_clear_cpu(cpu, policy->cpus);
1401 if (policy_is_inactive(policy)) {
1403 strncpy(policy->last_governor, policy->governor->name,
1405 } else if (cpu == policy->cpu) {
1406 /* Nominate new CPU */
1407 policy->cpu = cpumask_any(policy->cpus);
1409 up_write(&policy->rwsem);
1411 /* Start governor again for active policy */
1412 if (!policy_is_inactive(policy)) {
1414 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1416 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1419 pr_err("%s: Failed to start governor\n", __func__);
1421 } else if (cpufreq_driver->stop_cpu) {
1422 cpufreq_driver->stop_cpu(policy);
1426 static void cpufreq_offline_finish(unsigned int cpu)
1428 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1431 pr_debug("%s: No cpu_data found\n", __func__);
1435 /* Only proceed for inactive policies */
1436 if (!policy_is_inactive(policy))
1439 /* If cpu is last user of policy, free policy */
1441 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1443 pr_err("%s: Failed to exit governor\n", __func__);
1447 * Perform the ->exit() even during light-weight tear-down,
1448 * since this is a core component, and is essential for the
1449 * subsequent light-weight ->init() to succeed.
1451 if (cpufreq_driver->exit)
1452 cpufreq_driver->exit(policy);
1456 * cpufreq_remove_dev - remove a CPU device
1458 * Removes the cpufreq interface for a CPU device.
1460 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1462 unsigned int cpu = dev->id;
1463 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1468 if (cpu_online(cpu)) {
1469 cpufreq_offline_prepare(cpu);
1470 cpufreq_offline_finish(cpu);
1473 cpumask_clear_cpu(cpu, policy->real_cpus);
1475 if (cpumask_empty(policy->real_cpus)) {
1476 cpufreq_policy_free(policy, true);
1480 if (cpu != policy->kobj_cpu) {
1481 remove_cpu_dev_symlink(policy, cpu);
1484 * The CPU owning the policy object is going away. Move it to
1485 * another suitable CPU.
1487 unsigned int new_cpu = cpumask_first(policy->real_cpus);
1488 struct device *new_dev = get_cpu_device(new_cpu);
1490 dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
1492 sysfs_remove_link(&new_dev->kobj, "cpufreq");
1493 policy->kobj_cpu = new_cpu;
1494 WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
1500 static void handle_update(struct work_struct *work)
1502 struct cpufreq_policy *policy =
1503 container_of(work, struct cpufreq_policy, update);
1504 unsigned int cpu = policy->cpu;
1505 pr_debug("handle_update for cpu %u called\n", cpu);
1506 cpufreq_update_policy(cpu);
1510 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1512 * @policy: policy managing CPUs
1513 * @new_freq: CPU frequency the CPU actually runs at
1515 * We adjust to current frequency first, and need to clean up later.
1516 * So either call to cpufreq_update_policy() or schedule handle_update()).
1518 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1519 unsigned int new_freq)
1521 struct cpufreq_freqs freqs;
1523 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1524 policy->cur, new_freq);
1526 freqs.old = policy->cur;
1527 freqs.new = new_freq;
1529 cpufreq_freq_transition_begin(policy, &freqs);
1530 cpufreq_freq_transition_end(policy, &freqs, 0);
1534 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1537 * This is the last known freq, without actually getting it from the driver.
1538 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1540 unsigned int cpufreq_quick_get(unsigned int cpu)
1542 struct cpufreq_policy *policy;
1543 unsigned int ret_freq = 0;
1545 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1546 return cpufreq_driver->get(cpu);
1548 policy = cpufreq_cpu_get(cpu);
1550 ret_freq = policy->cur;
1551 cpufreq_cpu_put(policy);
1556 EXPORT_SYMBOL(cpufreq_quick_get);
1559 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1562 * Just return the max possible frequency for a given CPU.
1564 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1566 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1567 unsigned int ret_freq = 0;
1570 ret_freq = policy->max;
1571 cpufreq_cpu_put(policy);
1576 EXPORT_SYMBOL(cpufreq_quick_get_max);
1578 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1580 unsigned int ret_freq = 0;
1582 if (!cpufreq_driver->get)
1585 ret_freq = cpufreq_driver->get(policy->cpu);
1587 /* Updating inactive policies is invalid, so avoid doing that. */
1588 if (unlikely(policy_is_inactive(policy)))
1591 if (ret_freq && policy->cur &&
1592 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1593 /* verify no discrepancy between actual and
1594 saved value exists */
1595 if (unlikely(ret_freq != policy->cur)) {
1596 cpufreq_out_of_sync(policy, ret_freq);
1597 schedule_work(&policy->update);
1605 * cpufreq_get - get the current CPU frequency (in kHz)
1608 * Get the CPU current (static) CPU frequency
1610 unsigned int cpufreq_get(unsigned int cpu)
1612 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1613 unsigned int ret_freq = 0;
1616 down_read(&policy->rwsem);
1617 ret_freq = __cpufreq_get(policy);
1618 up_read(&policy->rwsem);
1620 cpufreq_cpu_put(policy);
1625 EXPORT_SYMBOL(cpufreq_get);
1627 static struct subsys_interface cpufreq_interface = {
1629 .subsys = &cpu_subsys,
1630 .add_dev = cpufreq_add_dev,
1631 .remove_dev = cpufreq_remove_dev,
1635 * In case platform wants some specific frequency to be configured
1638 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1642 if (!policy->suspend_freq) {
1643 pr_err("%s: suspend_freq can't be zero\n", __func__);
1647 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1648 policy->suspend_freq);
1650 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1651 CPUFREQ_RELATION_H);
1653 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1654 __func__, policy->suspend_freq, ret);
1658 EXPORT_SYMBOL(cpufreq_generic_suspend);
1661 * cpufreq_suspend() - Suspend CPUFreq governors
1663 * Called during system wide Suspend/Hibernate cycles for suspending governors
1664 * as some platforms can't change frequency after this point in suspend cycle.
1665 * Because some of the devices (like: i2c, regulators, etc) they use for
1666 * changing frequency are suspended quickly after this point.
1668 void cpufreq_suspend(void)
1670 struct cpufreq_policy *policy;
1672 if (!cpufreq_driver)
1678 pr_debug("%s: Suspending Governors\n", __func__);
1680 for_each_active_policy(policy) {
1681 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1682 pr_err("%s: Failed to stop governor for policy: %p\n",
1684 else if (cpufreq_driver->suspend
1685 && cpufreq_driver->suspend(policy))
1686 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1691 cpufreq_suspended = true;
1695 * cpufreq_resume() - Resume CPUFreq governors
1697 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1698 * are suspended with cpufreq_suspend().
1700 void cpufreq_resume(void)
1702 struct cpufreq_policy *policy;
1704 if (!cpufreq_driver)
1707 cpufreq_suspended = false;
1712 pr_debug("%s: Resuming Governors\n", __func__);
1714 for_each_active_policy(policy) {
1715 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1716 pr_err("%s: Failed to resume driver: %p\n", __func__,
1718 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1719 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1720 pr_err("%s: Failed to start governor for policy: %p\n",
1725 * schedule call cpufreq_update_policy() for first-online CPU, as that
1726 * wouldn't be hotplugged-out on suspend. It will verify that the
1727 * current freq is in sync with what we believe it to be.
1729 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1730 if (WARN_ON(!policy))
1733 schedule_work(&policy->update);
1737 * cpufreq_get_current_driver - return current driver's name
1739 * Return the name string of the currently loaded cpufreq driver
1742 const char *cpufreq_get_current_driver(void)
1745 return cpufreq_driver->name;
1749 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1752 * cpufreq_get_driver_data - return current driver data
1754 * Return the private data of the currently loaded cpufreq
1755 * driver, or NULL if no cpufreq driver is loaded.
1757 void *cpufreq_get_driver_data(void)
1760 return cpufreq_driver->driver_data;
1764 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1766 /*********************************************************************
1767 * NOTIFIER LISTS INTERFACE *
1768 *********************************************************************/
1771 * cpufreq_register_notifier - register a driver with cpufreq
1772 * @nb: notifier function to register
1773 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1775 * Add a driver to one of two lists: either a list of drivers that
1776 * are notified about clock rate changes (once before and once after
1777 * the transition), or a list of drivers that are notified about
1778 * changes in cpufreq policy.
1780 * This function may sleep, and has the same return conditions as
1781 * blocking_notifier_chain_register.
1783 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1787 if (cpufreq_disabled())
1790 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1793 case CPUFREQ_TRANSITION_NOTIFIER:
1794 ret = srcu_notifier_chain_register(
1795 &cpufreq_transition_notifier_list, nb);
1797 case CPUFREQ_POLICY_NOTIFIER:
1798 ret = blocking_notifier_chain_register(
1799 &cpufreq_policy_notifier_list, nb);
1807 EXPORT_SYMBOL(cpufreq_register_notifier);
1810 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1811 * @nb: notifier block to be unregistered
1812 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1814 * Remove a driver from the CPU frequency notifier list.
1816 * This function may sleep, and has the same return conditions as
1817 * blocking_notifier_chain_unregister.
1819 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1823 if (cpufreq_disabled())
1827 case CPUFREQ_TRANSITION_NOTIFIER:
1828 ret = srcu_notifier_chain_unregister(
1829 &cpufreq_transition_notifier_list, nb);
1831 case CPUFREQ_POLICY_NOTIFIER:
1832 ret = blocking_notifier_chain_unregister(
1833 &cpufreq_policy_notifier_list, nb);
1841 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1844 /*********************************************************************
1846 *********************************************************************/
1848 /* Must set freqs->new to intermediate frequency */
1849 static int __target_intermediate(struct cpufreq_policy *policy,
1850 struct cpufreq_freqs *freqs, int index)
1854 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1856 /* We don't need to switch to intermediate freq */
1860 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1861 __func__, policy->cpu, freqs->old, freqs->new);
1863 cpufreq_freq_transition_begin(policy, freqs);
1864 ret = cpufreq_driver->target_intermediate(policy, index);
1865 cpufreq_freq_transition_end(policy, freqs, ret);
1868 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1874 static int __target_index(struct cpufreq_policy *policy,
1875 struct cpufreq_frequency_table *freq_table, int index)
1877 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1878 unsigned int intermediate_freq = 0;
1879 int retval = -EINVAL;
1882 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1884 /* Handle switching to intermediate frequency */
1885 if (cpufreq_driver->get_intermediate) {
1886 retval = __target_intermediate(policy, &freqs, index);
1890 intermediate_freq = freqs.new;
1891 /* Set old freq to intermediate */
1892 if (intermediate_freq)
1893 freqs.old = freqs.new;
1896 freqs.new = freq_table[index].frequency;
1897 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1898 __func__, policy->cpu, freqs.old, freqs.new);
1900 cpufreq_freq_transition_begin(policy, &freqs);
1903 retval = cpufreq_driver->target_index(policy, index);
1905 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1909 cpufreq_freq_transition_end(policy, &freqs, retval);
1912 * Failed after setting to intermediate freq? Driver should have
1913 * reverted back to initial frequency and so should we. Check
1914 * here for intermediate_freq instead of get_intermediate, in
1915 * case we haven't switched to intermediate freq at all.
1917 if (unlikely(retval && intermediate_freq)) {
1918 freqs.old = intermediate_freq;
1919 freqs.new = policy->restore_freq;
1920 cpufreq_freq_transition_begin(policy, &freqs);
1921 cpufreq_freq_transition_end(policy, &freqs, 0);
1928 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1929 unsigned int target_freq,
1930 unsigned int relation)
1932 unsigned int old_target_freq = target_freq;
1933 int retval = -EINVAL;
1935 if (cpufreq_disabled())
1938 /* Make sure that target_freq is within supported range */
1939 if (target_freq > policy->max)
1940 target_freq = policy->max;
1941 if (target_freq < policy->min)
1942 target_freq = policy->min;
1944 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1945 policy->cpu, target_freq, relation, old_target_freq);
1948 * This might look like a redundant call as we are checking it again
1949 * after finding index. But it is left intentionally for cases where
1950 * exactly same freq is called again and so we can save on few function
1953 if (target_freq == policy->cur)
1956 /* Save last value to restore later on errors */
1957 policy->restore_freq = policy->cur;
1959 if (cpufreq_driver->target)
1960 retval = cpufreq_driver->target(policy, target_freq, relation);
1961 else if (cpufreq_driver->target_index) {
1962 struct cpufreq_frequency_table *freq_table;
1965 freq_table = cpufreq_frequency_get_table(policy->cpu);
1966 if (unlikely(!freq_table)) {
1967 pr_err("%s: Unable to find freq_table\n", __func__);
1971 retval = cpufreq_frequency_table_target(policy, freq_table,
1972 target_freq, relation, &index);
1973 if (unlikely(retval)) {
1974 pr_err("%s: Unable to find matching freq\n", __func__);
1978 if (freq_table[index].frequency == policy->cur) {
1983 retval = __target_index(policy, freq_table, index);
1989 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1991 int cpufreq_driver_target(struct cpufreq_policy *policy,
1992 unsigned int target_freq,
1993 unsigned int relation)
1997 down_write(&policy->rwsem);
1999 ret = __cpufreq_driver_target(policy, target_freq, relation);
2001 up_write(&policy->rwsem);
2005 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2007 static int __cpufreq_governor(struct cpufreq_policy *policy,
2012 /* Only must be defined when default governor is known to have latency
2013 restrictions, like e.g. conservative or ondemand.
2014 That this is the case is already ensured in Kconfig
2016 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2017 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2019 struct cpufreq_governor *gov = NULL;
2022 /* Don't start any governor operations if we are entering suspend */
2023 if (cpufreq_suspended)
2026 * Governor might not be initiated here if ACPI _PPC changed
2027 * notification happened, so check it.
2029 if (!policy->governor)
2032 if (policy->governor->max_transition_latency &&
2033 policy->cpuinfo.transition_latency >
2034 policy->governor->max_transition_latency) {
2038 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2039 policy->governor->name, gov->name);
2040 policy->governor = gov;
2044 if (event == CPUFREQ_GOV_POLICY_INIT)
2045 if (!try_module_get(policy->governor->owner))
2048 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2049 policy->cpu, event);
2051 mutex_lock(&cpufreq_governor_lock);
2052 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2053 || (!policy->governor_enabled
2054 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2055 mutex_unlock(&cpufreq_governor_lock);
2059 if (event == CPUFREQ_GOV_STOP)
2060 policy->governor_enabled = false;
2061 else if (event == CPUFREQ_GOV_START)
2062 policy->governor_enabled = true;
2064 mutex_unlock(&cpufreq_governor_lock);
2066 ret = policy->governor->governor(policy, event);
2069 if (event == CPUFREQ_GOV_POLICY_INIT)
2070 policy->governor->initialized++;
2071 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2072 policy->governor->initialized--;
2074 /* Restore original values */
2075 mutex_lock(&cpufreq_governor_lock);
2076 if (event == CPUFREQ_GOV_STOP)
2077 policy->governor_enabled = true;
2078 else if (event == CPUFREQ_GOV_START)
2079 policy->governor_enabled = false;
2080 mutex_unlock(&cpufreq_governor_lock);
2083 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2084 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2085 module_put(policy->governor->owner);
2090 int cpufreq_register_governor(struct cpufreq_governor *governor)
2097 if (cpufreq_disabled())
2100 mutex_lock(&cpufreq_governor_mutex);
2102 governor->initialized = 0;
2104 if (!find_governor(governor->name)) {
2106 list_add(&governor->governor_list, &cpufreq_governor_list);
2109 mutex_unlock(&cpufreq_governor_mutex);
2112 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2114 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2116 struct cpufreq_policy *policy;
2117 unsigned long flags;
2122 if (cpufreq_disabled())
2125 /* clear last_governor for all inactive policies */
2126 read_lock_irqsave(&cpufreq_driver_lock, flags);
2127 for_each_inactive_policy(policy) {
2128 if (!strcmp(policy->last_governor, governor->name)) {
2129 policy->governor = NULL;
2130 strcpy(policy->last_governor, "\0");
2133 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2135 mutex_lock(&cpufreq_governor_mutex);
2136 list_del(&governor->governor_list);
2137 mutex_unlock(&cpufreq_governor_mutex);
2140 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2143 /*********************************************************************
2144 * POLICY INTERFACE *
2145 *********************************************************************/
2148 * cpufreq_get_policy - get the current cpufreq_policy
2149 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2152 * Reads the current cpufreq policy.
2154 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2156 struct cpufreq_policy *cpu_policy;
2160 cpu_policy = cpufreq_cpu_get(cpu);
2164 memcpy(policy, cpu_policy, sizeof(*policy));
2166 cpufreq_cpu_put(cpu_policy);
2169 EXPORT_SYMBOL(cpufreq_get_policy);
2172 * policy : current policy.
2173 * new_policy: policy to be set.
2175 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2176 struct cpufreq_policy *new_policy)
2178 struct cpufreq_governor *old_gov;
2181 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2182 new_policy->cpu, new_policy->min, new_policy->max);
2184 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2186 if (new_policy->min > policy->max || new_policy->max < policy->min)
2189 /* verify the cpu speed can be set within this limit */
2190 ret = cpufreq_driver->verify(new_policy);
2194 /* adjust if necessary - all reasons */
2195 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2196 CPUFREQ_ADJUST, new_policy);
2198 /* adjust if necessary - hardware incompatibility*/
2199 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2200 CPUFREQ_INCOMPATIBLE, new_policy);
2203 * verify the cpu speed can be set within this limit, which might be
2204 * different to the first one
2206 ret = cpufreq_driver->verify(new_policy);
2210 /* notification of the new policy */
2211 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2212 CPUFREQ_NOTIFY, new_policy);
2214 policy->min = new_policy->min;
2215 policy->max = new_policy->max;
2217 pr_debug("new min and max freqs are %u - %u kHz\n",
2218 policy->min, policy->max);
2220 if (cpufreq_driver->setpolicy) {
2221 policy->policy = new_policy->policy;
2222 pr_debug("setting range\n");
2223 return cpufreq_driver->setpolicy(new_policy);
2226 if (new_policy->governor == policy->governor)
2229 pr_debug("governor switch\n");
2231 /* save old, working values */
2232 old_gov = policy->governor;
2233 /* end old governor */
2235 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2237 /* This can happen due to race with other operations */
2238 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2239 __func__, old_gov->name, ret);
2243 up_write(&policy->rwsem);
2244 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2245 down_write(&policy->rwsem);
2248 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2249 __func__, old_gov->name, ret);
2254 /* start new governor */
2255 policy->governor = new_policy->governor;
2256 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2258 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2262 up_write(&policy->rwsem);
2263 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2264 down_write(&policy->rwsem);
2267 /* new governor failed, so re-start old one */
2268 pr_debug("starting governor %s failed\n", policy->governor->name);
2270 policy->governor = old_gov;
2271 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2272 policy->governor = NULL;
2274 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2280 pr_debug("governor: change or update limits\n");
2281 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2285 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2286 * @cpu: CPU which shall be re-evaluated
2288 * Useful for policy notifiers which have different necessities
2289 * at different times.
2291 int cpufreq_update_policy(unsigned int cpu)
2293 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2294 struct cpufreq_policy new_policy;
2300 down_write(&policy->rwsem);
2302 pr_debug("updating policy for CPU %u\n", cpu);
2303 memcpy(&new_policy, policy, sizeof(*policy));
2304 new_policy.min = policy->user_policy.min;
2305 new_policy.max = policy->user_policy.max;
2306 new_policy.policy = policy->user_policy.policy;
2307 new_policy.governor = policy->user_policy.governor;
2310 * BIOS might change freq behind our back
2311 * -> ask driver for current freq and notify governors about a change
2313 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2314 new_policy.cur = cpufreq_driver->get(cpu);
2315 if (WARN_ON(!new_policy.cur)) {
2321 pr_debug("Driver did not initialize current freq\n");
2322 policy->cur = new_policy.cur;
2324 if (policy->cur != new_policy.cur && has_target())
2325 cpufreq_out_of_sync(policy, new_policy.cur);
2329 ret = cpufreq_set_policy(policy, &new_policy);
2332 up_write(&policy->rwsem);
2334 cpufreq_cpu_put(policy);
2337 EXPORT_SYMBOL(cpufreq_update_policy);
2339 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2340 unsigned long action, void *hcpu)
2342 unsigned int cpu = (unsigned long)hcpu;
2345 dev = get_cpu_device(cpu);
2347 switch (action & ~CPU_TASKS_FROZEN) {
2349 cpufreq_add_dev(dev, NULL);
2352 case CPU_DOWN_PREPARE:
2353 cpufreq_offline_prepare(cpu);
2357 cpufreq_offline_finish(cpu);
2360 case CPU_DOWN_FAILED:
2361 cpufreq_add_dev(dev, NULL);
2368 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2369 .notifier_call = cpufreq_cpu_callback,
2372 /*********************************************************************
2374 *********************************************************************/
2375 static int cpufreq_boost_set_sw(int state)
2377 struct cpufreq_frequency_table *freq_table;
2378 struct cpufreq_policy *policy;
2381 for_each_active_policy(policy) {
2382 freq_table = cpufreq_frequency_get_table(policy->cpu);
2384 ret = cpufreq_frequency_table_cpuinfo(policy,
2387 pr_err("%s: Policy frequency update failed\n",
2391 policy->user_policy.max = policy->max;
2392 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2399 int cpufreq_boost_trigger_state(int state)
2401 unsigned long flags;
2404 if (cpufreq_driver->boost_enabled == state)
2407 write_lock_irqsave(&cpufreq_driver_lock, flags);
2408 cpufreq_driver->boost_enabled = state;
2409 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2411 ret = cpufreq_driver->set_boost(state);
2413 write_lock_irqsave(&cpufreq_driver_lock, flags);
2414 cpufreq_driver->boost_enabled = !state;
2415 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2417 pr_err("%s: Cannot %s BOOST\n",
2418 __func__, state ? "enable" : "disable");
2424 int cpufreq_boost_supported(void)
2426 if (likely(cpufreq_driver))
2427 return cpufreq_driver->boost_supported;
2431 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2433 int cpufreq_boost_enabled(void)
2435 return cpufreq_driver->boost_enabled;
2437 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2439 /*********************************************************************
2440 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2441 *********************************************************************/
2444 * cpufreq_register_driver - register a CPU Frequency driver
2445 * @driver_data: A struct cpufreq_driver containing the values#
2446 * submitted by the CPU Frequency driver.
2448 * Registers a CPU Frequency driver to this core code. This code
2449 * returns zero on success, -EBUSY when another driver got here first
2450 * (and isn't unregistered in the meantime).
2453 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2455 unsigned long flags;
2458 if (cpufreq_disabled())
2461 if (!driver_data || !driver_data->verify || !driver_data->init ||
2462 !(driver_data->setpolicy || driver_data->target_index ||
2463 driver_data->target) ||
2464 (driver_data->setpolicy && (driver_data->target_index ||
2465 driver_data->target)) ||
2466 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2469 pr_debug("trying to register driver %s\n", driver_data->name);
2471 write_lock_irqsave(&cpufreq_driver_lock, flags);
2472 if (cpufreq_driver) {
2473 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2476 cpufreq_driver = driver_data;
2477 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2479 if (driver_data->setpolicy)
2480 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2482 if (cpufreq_boost_supported()) {
2484 * Check if driver provides function to enable boost -
2485 * if not, use cpufreq_boost_set_sw as default
2487 if (!cpufreq_driver->set_boost)
2488 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2490 ret = cpufreq_sysfs_create_file(&boost.attr);
2492 pr_err("%s: cannot register global BOOST sysfs file\n",
2494 goto err_null_driver;
2498 ret = subsys_interface_register(&cpufreq_interface);
2500 goto err_boost_unreg;
2502 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2503 list_empty(&cpufreq_policy_list)) {
2504 /* if all ->init() calls failed, unregister */
2505 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2510 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2511 pr_debug("driver %s up and running\n", driver_data->name);
2515 subsys_interface_unregister(&cpufreq_interface);
2517 if (cpufreq_boost_supported())
2518 cpufreq_sysfs_remove_file(&boost.attr);
2520 write_lock_irqsave(&cpufreq_driver_lock, flags);
2521 cpufreq_driver = NULL;
2522 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2525 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2528 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2530 * Unregister the current CPUFreq driver. Only call this if you have
2531 * the right to do so, i.e. if you have succeeded in initialising before!
2532 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2533 * currently not initialised.
2535 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2537 unsigned long flags;
2539 if (!cpufreq_driver || (driver != cpufreq_driver))
2542 pr_debug("unregistering driver %s\n", driver->name);
2544 /* Protect against concurrent cpu hotplug */
2546 subsys_interface_unregister(&cpufreq_interface);
2547 if (cpufreq_boost_supported())
2548 cpufreq_sysfs_remove_file(&boost.attr);
2550 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2552 write_lock_irqsave(&cpufreq_driver_lock, flags);
2554 cpufreq_driver = NULL;
2556 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2561 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2564 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2565 * or mutexes when secondary CPUs are halted.
2567 static struct syscore_ops cpufreq_syscore_ops = {
2568 .shutdown = cpufreq_suspend,
2571 static int __init cpufreq_core_init(void)
2573 if (cpufreq_disabled())
2576 cpufreq_global_kobject = kobject_create();
2577 BUG_ON(!cpufreq_global_kobject);
2579 register_syscore_ops(&cpufreq_syscore_ops);
2583 core_initcall(cpufreq_core_init);