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/tick.h>
31 #include <trace/events/power.h>
34 * The "cpufreq driver" - the arch- or hardware-dependent low
35 * level driver of CPUFreq support, and its spinlock. This lock
36 * also protects the cpufreq_cpu_data array.
38 static struct cpufreq_driver *cpufreq_driver;
39 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
40 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
41 static DEFINE_RWLOCK(cpufreq_driver_lock);
42 DEFINE_MUTEX(cpufreq_governor_lock);
43 static LIST_HEAD(cpufreq_policy_list);
45 /* This one keeps track of the previously set governor of a removed CPU */
46 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
48 /* Flag to suspend/resume CPUFreq governors */
49 static bool cpufreq_suspended;
51 static inline bool has_target(void)
53 return cpufreq_driver->target_index || cpufreq_driver->target;
57 * rwsem to guarantee that cpufreq driver module doesn't unload during critical
60 static DECLARE_RWSEM(cpufreq_rwsem);
62 /* internal prototypes */
63 static int __cpufreq_governor(struct cpufreq_policy *policy,
65 static unsigned int __cpufreq_get(unsigned int cpu);
66 static void handle_update(struct work_struct *work);
69 * Two notifier lists: the "policy" list is involved in the
70 * validation process for a new CPU frequency policy; the
71 * "transition" list for kernel code that needs to handle
72 * changes to devices when the CPU clock speed changes.
73 * The mutex locks both lists.
75 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
76 static struct srcu_notifier_head cpufreq_transition_notifier_list;
78 static bool init_cpufreq_transition_notifier_list_called;
79 static int __init init_cpufreq_transition_notifier_list(void)
81 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
82 init_cpufreq_transition_notifier_list_called = true;
85 pure_initcall(init_cpufreq_transition_notifier_list);
87 static int off __read_mostly;
88 static int cpufreq_disabled(void)
92 void disable_cpufreq(void)
96 static LIST_HEAD(cpufreq_governor_list);
97 static DEFINE_MUTEX(cpufreq_governor_mutex);
99 bool have_governor_per_policy(void)
101 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
103 EXPORT_SYMBOL_GPL(have_governor_per_policy);
105 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
107 if (have_governor_per_policy())
108 return &policy->kobj;
110 return cpufreq_global_kobject;
112 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
114 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
120 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
122 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
123 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
124 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
125 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
126 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
127 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
129 idle_time = cur_wall_time - busy_time;
131 *wall = cputime_to_usecs(cur_wall_time);
133 return cputime_to_usecs(idle_time);
136 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
138 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
140 if (idle_time == -1ULL)
141 return get_cpu_idle_time_jiffy(cpu, wall);
143 idle_time += get_cpu_iowait_time_us(cpu, wall);
147 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
150 * This is a generic cpufreq init() routine which can be used by cpufreq
151 * drivers of SMP systems. It will do following:
152 * - validate & show freq table passed
153 * - set policies transition latency
154 * - policy->cpus with all possible CPUs
156 int cpufreq_generic_init(struct cpufreq_policy *policy,
157 struct cpufreq_frequency_table *table,
158 unsigned int transition_latency)
162 ret = cpufreq_table_validate_and_show(policy, table);
164 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
168 policy->cpuinfo.transition_latency = transition_latency;
171 * The driver only supports the SMP configuartion where all processors
172 * share the clock and voltage and clock.
174 cpumask_setall(policy->cpus);
178 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
180 unsigned int cpufreq_generic_get(unsigned int cpu)
182 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
184 if (!policy || IS_ERR(policy->clk)) {
185 pr_err("%s: No %s associated to cpu: %d\n",
186 __func__, policy ? "clk" : "policy", cpu);
190 return clk_get_rate(policy->clk) / 1000;
192 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
194 /* Only for cpufreq core internal use */
195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
197 return per_cpu(cpufreq_cpu_data, cpu);
200 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
202 struct cpufreq_policy *policy = NULL;
205 if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
208 if (!down_read_trylock(&cpufreq_rwsem))
211 /* get the cpufreq driver */
212 read_lock_irqsave(&cpufreq_driver_lock, flags);
214 if (cpufreq_driver) {
216 policy = per_cpu(cpufreq_cpu_data, cpu);
218 kobject_get(&policy->kobj);
221 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
224 up_read(&cpufreq_rwsem);
228 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
230 void cpufreq_cpu_put(struct cpufreq_policy *policy)
232 if (cpufreq_disabled())
235 kobject_put(&policy->kobj);
236 up_read(&cpufreq_rwsem);
238 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
240 /*********************************************************************
241 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
242 *********************************************************************/
245 * adjust_jiffies - adjust the system "loops_per_jiffy"
247 * This function alters the system "loops_per_jiffy" for the clock
248 * speed change. Note that loops_per_jiffy cannot be updated on SMP
249 * systems as each CPU might be scaled differently. So, use the arch
250 * per-CPU loops_per_jiffy value wherever possible.
253 static unsigned long l_p_j_ref;
254 static unsigned int l_p_j_ref_freq;
256 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
258 if (ci->flags & CPUFREQ_CONST_LOOPS)
261 if (!l_p_j_ref_freq) {
262 l_p_j_ref = loops_per_jiffy;
263 l_p_j_ref_freq = ci->old;
264 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
265 l_p_j_ref, l_p_j_ref_freq);
267 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
268 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
270 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
271 loops_per_jiffy, ci->new);
275 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
281 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
282 struct cpufreq_freqs *freqs, unsigned int state)
284 BUG_ON(irqs_disabled());
286 if (cpufreq_disabled())
289 freqs->flags = cpufreq_driver->flags;
290 pr_debug("notification %u of frequency transition to %u kHz\n",
295 case CPUFREQ_PRECHANGE:
296 /* detect if the driver reported a value as "old frequency"
297 * which is not equal to what the cpufreq core thinks is
300 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
301 if ((policy) && (policy->cpu == freqs->cpu) &&
302 (policy->cur) && (policy->cur != freqs->old)) {
303 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
304 freqs->old, policy->cur);
305 freqs->old = policy->cur;
308 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
309 CPUFREQ_PRECHANGE, freqs);
310 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
313 case CPUFREQ_POSTCHANGE:
314 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
315 pr_debug("FREQ: %lu - CPU: %lu\n",
316 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
317 trace_cpu_frequency(freqs->new, freqs->cpu);
318 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
319 CPUFREQ_POSTCHANGE, freqs);
320 if (likely(policy) && likely(policy->cpu == freqs->cpu))
321 policy->cur = freqs->new;
327 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
328 * on frequency transition.
330 * This function calls the transition notifiers and the "adjust_jiffies"
331 * function. It is called twice on all CPU frequency changes that have
334 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
335 struct cpufreq_freqs *freqs, unsigned int state)
337 for_each_cpu(freqs->cpu, policy->cpus)
338 __cpufreq_notify_transition(policy, freqs, state);
341 /* Do post notifications when there are chances that transition has failed */
342 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
343 struct cpufreq_freqs *freqs, int transition_failed)
345 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
346 if (!transition_failed)
349 swap(freqs->old, freqs->new);
350 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
351 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
354 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
355 struct cpufreq_freqs *freqs)
359 * Catch double invocations of _begin() which lead to self-deadlock.
360 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
361 * doesn't invoke _begin() on their behalf, and hence the chances of
362 * double invocations are very low. Moreover, there are scenarios
363 * where these checks can emit false-positive warnings in these
364 * drivers; so we avoid that by skipping them altogether.
366 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
367 && current == policy->transition_task);
370 wait_event(policy->transition_wait, !policy->transition_ongoing);
372 spin_lock(&policy->transition_lock);
374 if (unlikely(policy->transition_ongoing)) {
375 spin_unlock(&policy->transition_lock);
379 policy->transition_ongoing = true;
380 policy->transition_task = current;
382 spin_unlock(&policy->transition_lock);
384 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
386 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
388 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
389 struct cpufreq_freqs *freqs, int transition_failed)
391 if (unlikely(WARN_ON(!policy->transition_ongoing)))
394 cpufreq_notify_post_transition(policy, freqs, transition_failed);
396 policy->transition_ongoing = false;
397 policy->transition_task = NULL;
399 wake_up(&policy->transition_wait);
401 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
404 /*********************************************************************
406 *********************************************************************/
407 static ssize_t show_boost(struct kobject *kobj,
408 struct attribute *attr, char *buf)
410 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
413 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
414 const char *buf, size_t count)
418 ret = sscanf(buf, "%d", &enable);
419 if (ret != 1 || enable < 0 || enable > 1)
422 if (cpufreq_boost_trigger_state(enable)) {
423 pr_err("%s: Cannot %s BOOST!\n",
424 __func__, enable ? "enable" : "disable");
428 pr_debug("%s: cpufreq BOOST %s\n",
429 __func__, enable ? "enabled" : "disabled");
433 define_one_global_rw(boost);
435 static struct cpufreq_governor *__find_governor(const char *str_governor)
437 struct cpufreq_governor *t;
439 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
440 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
447 * cpufreq_parse_governor - parse a governor string
449 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
450 struct cpufreq_governor **governor)
457 if (cpufreq_driver->setpolicy) {
458 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
459 *policy = CPUFREQ_POLICY_PERFORMANCE;
461 } else if (!strncasecmp(str_governor, "powersave",
463 *policy = CPUFREQ_POLICY_POWERSAVE;
466 } else if (has_target()) {
467 struct cpufreq_governor *t;
469 mutex_lock(&cpufreq_governor_mutex);
471 t = __find_governor(str_governor);
476 mutex_unlock(&cpufreq_governor_mutex);
477 ret = request_module("cpufreq_%s", str_governor);
478 mutex_lock(&cpufreq_governor_mutex);
481 t = __find_governor(str_governor);
489 mutex_unlock(&cpufreq_governor_mutex);
496 * cpufreq_per_cpu_attr_read() / show_##file_name() -
497 * print out cpufreq information
499 * Write out information from cpufreq_driver->policy[cpu]; object must be
503 #define show_one(file_name, object) \
504 static ssize_t show_##file_name \
505 (struct cpufreq_policy *policy, char *buf) \
507 return sprintf(buf, "%u\n", policy->object); \
510 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
511 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
512 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
513 show_one(scaling_min_freq, min);
514 show_one(scaling_max_freq, max);
516 static ssize_t show_scaling_cur_freq(
517 struct cpufreq_policy *policy, char *buf)
521 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
522 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
524 ret = sprintf(buf, "%u\n", policy->cur);
528 static int cpufreq_set_policy(struct cpufreq_policy *policy,
529 struct cpufreq_policy *new_policy);
532 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
534 #define store_one(file_name, object) \
535 static ssize_t store_##file_name \
536 (struct cpufreq_policy *policy, const char *buf, size_t count) \
539 struct cpufreq_policy new_policy; \
541 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
545 ret = sscanf(buf, "%u", &new_policy.object); \
549 ret = cpufreq_set_policy(policy, &new_policy); \
550 policy->user_policy.object = policy->object; \
552 return ret ? ret : count; \
555 store_one(scaling_min_freq, min);
556 store_one(scaling_max_freq, max);
559 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
561 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
564 unsigned int cur_freq = __cpufreq_get(policy->cpu);
566 return sprintf(buf, "<unknown>");
567 return sprintf(buf, "%u\n", cur_freq);
571 * show_scaling_governor - show the current policy for the specified CPU
573 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
575 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
576 return sprintf(buf, "powersave\n");
577 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
578 return sprintf(buf, "performance\n");
579 else if (policy->governor)
580 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
581 policy->governor->name);
586 * store_scaling_governor - store policy for the specified CPU
588 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
589 const char *buf, size_t count)
592 char str_governor[16];
593 struct cpufreq_policy new_policy;
595 ret = cpufreq_get_policy(&new_policy, policy->cpu);
599 ret = sscanf(buf, "%15s", str_governor);
603 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
604 &new_policy.governor))
607 ret = cpufreq_set_policy(policy, &new_policy);
609 policy->user_policy.policy = policy->policy;
610 policy->user_policy.governor = policy->governor;
619 * show_scaling_driver - show the cpufreq driver currently loaded
621 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
623 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
627 * show_scaling_available_governors - show the available CPUfreq governors
629 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
633 struct cpufreq_governor *t;
636 i += sprintf(buf, "performance powersave");
640 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
641 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
642 - (CPUFREQ_NAME_LEN + 2)))
644 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
647 i += sprintf(&buf[i], "\n");
651 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
656 for_each_cpu(cpu, mask) {
658 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
659 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
660 if (i >= (PAGE_SIZE - 5))
663 i += sprintf(&buf[i], "\n");
666 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
669 * show_related_cpus - show the CPUs affected by each transition even if
670 * hw coordination is in use
672 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
674 return cpufreq_show_cpus(policy->related_cpus, buf);
678 * show_affected_cpus - show the CPUs affected by each transition
680 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
682 return cpufreq_show_cpus(policy->cpus, buf);
685 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
686 const char *buf, size_t count)
688 unsigned int freq = 0;
691 if (!policy->governor || !policy->governor->store_setspeed)
694 ret = sscanf(buf, "%u", &freq);
698 policy->governor->store_setspeed(policy, freq);
703 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
705 if (!policy->governor || !policy->governor->show_setspeed)
706 return sprintf(buf, "<unsupported>\n");
708 return policy->governor->show_setspeed(policy, buf);
712 * show_bios_limit - show the current cpufreq HW/BIOS limitation
714 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
718 if (cpufreq_driver->bios_limit) {
719 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
721 return sprintf(buf, "%u\n", limit);
723 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
726 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
727 cpufreq_freq_attr_ro(cpuinfo_min_freq);
728 cpufreq_freq_attr_ro(cpuinfo_max_freq);
729 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
730 cpufreq_freq_attr_ro(scaling_available_governors);
731 cpufreq_freq_attr_ro(scaling_driver);
732 cpufreq_freq_attr_ro(scaling_cur_freq);
733 cpufreq_freq_attr_ro(bios_limit);
734 cpufreq_freq_attr_ro(related_cpus);
735 cpufreq_freq_attr_ro(affected_cpus);
736 cpufreq_freq_attr_rw(scaling_min_freq);
737 cpufreq_freq_attr_rw(scaling_max_freq);
738 cpufreq_freq_attr_rw(scaling_governor);
739 cpufreq_freq_attr_rw(scaling_setspeed);
741 static struct attribute *default_attrs[] = {
742 &cpuinfo_min_freq.attr,
743 &cpuinfo_max_freq.attr,
744 &cpuinfo_transition_latency.attr,
745 &scaling_min_freq.attr,
746 &scaling_max_freq.attr,
749 &scaling_governor.attr,
750 &scaling_driver.attr,
751 &scaling_available_governors.attr,
752 &scaling_setspeed.attr,
756 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
757 #define to_attr(a) container_of(a, struct freq_attr, attr)
759 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
761 struct cpufreq_policy *policy = to_policy(kobj);
762 struct freq_attr *fattr = to_attr(attr);
765 if (!down_read_trylock(&cpufreq_rwsem))
768 down_read(&policy->rwsem);
771 ret = fattr->show(policy, buf);
775 up_read(&policy->rwsem);
776 up_read(&cpufreq_rwsem);
781 static ssize_t store(struct kobject *kobj, struct attribute *attr,
782 const char *buf, size_t count)
784 struct cpufreq_policy *policy = to_policy(kobj);
785 struct freq_attr *fattr = to_attr(attr);
786 ssize_t ret = -EINVAL;
790 if (!cpu_online(policy->cpu))
793 if (!down_read_trylock(&cpufreq_rwsem))
796 down_write(&policy->rwsem);
799 ret = fattr->store(policy, buf, count);
803 up_write(&policy->rwsem);
805 up_read(&cpufreq_rwsem);
812 static void cpufreq_sysfs_release(struct kobject *kobj)
814 struct cpufreq_policy *policy = to_policy(kobj);
815 pr_debug("last reference is dropped\n");
816 complete(&policy->kobj_unregister);
819 static const struct sysfs_ops sysfs_ops = {
824 static struct kobj_type ktype_cpufreq = {
825 .sysfs_ops = &sysfs_ops,
826 .default_attrs = default_attrs,
827 .release = cpufreq_sysfs_release,
830 struct kobject *cpufreq_global_kobject;
831 EXPORT_SYMBOL(cpufreq_global_kobject);
833 static int cpufreq_global_kobject_usage;
835 int cpufreq_get_global_kobject(void)
837 if (!cpufreq_global_kobject_usage++)
838 return kobject_add(cpufreq_global_kobject,
839 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
843 EXPORT_SYMBOL(cpufreq_get_global_kobject);
845 void cpufreq_put_global_kobject(void)
847 if (!--cpufreq_global_kobject_usage)
848 kobject_del(cpufreq_global_kobject);
850 EXPORT_SYMBOL(cpufreq_put_global_kobject);
852 int cpufreq_sysfs_create_file(const struct attribute *attr)
854 int ret = cpufreq_get_global_kobject();
857 ret = sysfs_create_file(cpufreq_global_kobject, attr);
859 cpufreq_put_global_kobject();
864 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
866 void cpufreq_sysfs_remove_file(const struct attribute *attr)
868 sysfs_remove_file(cpufreq_global_kobject, attr);
869 cpufreq_put_global_kobject();
871 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
873 /* symlink affected CPUs */
874 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
879 for_each_cpu(j, policy->cpus) {
880 struct device *cpu_dev;
882 if (j == policy->cpu)
885 pr_debug("Adding link for CPU: %u\n", j);
886 cpu_dev = get_cpu_device(j);
887 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
895 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
898 struct freq_attr **drv_attr;
901 /* prepare interface data */
902 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
903 &dev->kobj, "cpufreq");
907 /* set up files for this cpu device */
908 drv_attr = cpufreq_driver->attr;
909 while ((drv_attr) && (*drv_attr)) {
910 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
912 goto err_out_kobj_put;
915 if (cpufreq_driver->get) {
916 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
918 goto err_out_kobj_put;
921 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
923 goto err_out_kobj_put;
925 if (cpufreq_driver->bios_limit) {
926 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
928 goto err_out_kobj_put;
931 ret = cpufreq_add_dev_symlink(policy);
933 goto err_out_kobj_put;
938 kobject_put(&policy->kobj);
939 wait_for_completion(&policy->kobj_unregister);
943 static void cpufreq_init_policy(struct cpufreq_policy *policy)
945 struct cpufreq_governor *gov = NULL;
946 struct cpufreq_policy new_policy;
949 memcpy(&new_policy, policy, sizeof(*policy));
951 /* Update governor of new_policy to the governor used before hotplug */
952 gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
954 pr_debug("Restoring governor %s for cpu %d\n",
955 policy->governor->name, policy->cpu);
957 gov = CPUFREQ_DEFAULT_GOVERNOR;
959 new_policy.governor = gov;
961 /* Use the default policy if its valid. */
962 if (cpufreq_driver->setpolicy)
963 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
965 /* set default policy */
966 ret = cpufreq_set_policy(policy, &new_policy);
968 pr_debug("setting policy failed\n");
969 if (cpufreq_driver->exit)
970 cpufreq_driver->exit(policy);
974 #ifdef CONFIG_HOTPLUG_CPU
975 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
976 unsigned int cpu, struct device *dev)
982 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
984 pr_err("%s: Failed to stop governor\n", __func__);
989 down_write(&policy->rwsem);
991 write_lock_irqsave(&cpufreq_driver_lock, flags);
993 cpumask_set_cpu(cpu, policy->cpus);
994 per_cpu(cpufreq_cpu_data, cpu) = policy;
995 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
997 up_write(&policy->rwsem);
1000 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1002 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1005 pr_err("%s: Failed to start governor\n", __func__);
1010 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
1014 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
1016 struct cpufreq_policy *policy;
1017 unsigned long flags;
1019 read_lock_irqsave(&cpufreq_driver_lock, flags);
1021 policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
1023 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1025 policy->governor = NULL;
1030 static struct cpufreq_policy *cpufreq_policy_alloc(void)
1032 struct cpufreq_policy *policy;
1034 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1038 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1039 goto err_free_policy;
1041 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1042 goto err_free_cpumask;
1044 INIT_LIST_HEAD(&policy->policy_list);
1045 init_rwsem(&policy->rwsem);
1046 spin_lock_init(&policy->transition_lock);
1047 init_waitqueue_head(&policy->transition_wait);
1052 free_cpumask_var(policy->cpus);
1059 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1061 struct kobject *kobj;
1062 struct completion *cmp;
1064 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1065 CPUFREQ_REMOVE_POLICY, policy);
1067 down_read(&policy->rwsem);
1068 kobj = &policy->kobj;
1069 cmp = &policy->kobj_unregister;
1070 up_read(&policy->rwsem);
1074 * We need to make sure that the underlying kobj is
1075 * actually not referenced anymore by anybody before we
1076 * proceed with unloading.
1078 pr_debug("waiting for dropping of refcount\n");
1079 wait_for_completion(cmp);
1080 pr_debug("wait complete\n");
1083 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1085 free_cpumask_var(policy->related_cpus);
1086 free_cpumask_var(policy->cpus);
1090 static int update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu,
1091 struct device *cpu_dev)
1095 if (WARN_ON(cpu == policy->cpu))
1098 /* Move kobject to the new policy->cpu */
1099 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1101 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1105 down_write(&policy->rwsem);
1107 policy->last_cpu = policy->cpu;
1110 up_write(&policy->rwsem);
1112 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1113 CPUFREQ_UPDATE_POLICY_CPU, policy);
1118 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1120 unsigned int j, cpu = dev->id;
1122 struct cpufreq_policy *policy;
1123 unsigned long flags;
1124 bool recover_policy = cpufreq_suspended;
1125 #ifdef CONFIG_HOTPLUG_CPU
1126 struct cpufreq_policy *tpolicy;
1129 if (cpu_is_offline(cpu))
1132 pr_debug("adding CPU %u\n", cpu);
1135 /* check whether a different CPU already registered this
1136 * CPU because it is in the same boat. */
1137 policy = cpufreq_cpu_get(cpu);
1138 if (unlikely(policy)) {
1139 cpufreq_cpu_put(policy);
1144 if (!down_read_trylock(&cpufreq_rwsem))
1147 #ifdef CONFIG_HOTPLUG_CPU
1148 /* Check if this cpu was hot-unplugged earlier and has siblings */
1149 read_lock_irqsave(&cpufreq_driver_lock, flags);
1150 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1151 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1152 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1153 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1154 up_read(&cpufreq_rwsem);
1158 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1162 * Restore the saved policy when doing light-weight init and fall back
1163 * to the full init if that fails.
1165 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1167 recover_policy = false;
1168 policy = cpufreq_policy_alloc();
1174 * In the resume path, since we restore a saved policy, the assignment
1175 * to policy->cpu is like an update of the existing policy, rather than
1176 * the creation of a brand new one. So we need to perform this update
1177 * by invoking update_policy_cpu().
1179 if (recover_policy && cpu != policy->cpu)
1180 WARN_ON(update_policy_cpu(policy, cpu, dev));
1184 cpumask_copy(policy->cpus, cpumask_of(cpu));
1186 init_completion(&policy->kobj_unregister);
1187 INIT_WORK(&policy->update, handle_update);
1189 /* call driver. From then on the cpufreq must be able
1190 * to accept all calls to ->verify and ->setpolicy for this CPU
1192 ret = cpufreq_driver->init(policy);
1194 pr_debug("initialization failed\n");
1195 goto err_set_policy_cpu;
1198 /* related cpus should atleast have policy->cpus */
1199 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1202 * affected cpus must always be the one, which are online. We aren't
1203 * managing offline cpus here.
1205 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1207 if (!recover_policy) {
1208 policy->user_policy.min = policy->min;
1209 policy->user_policy.max = policy->max;
1212 down_write(&policy->rwsem);
1213 write_lock_irqsave(&cpufreq_driver_lock, flags);
1214 for_each_cpu(j, policy->cpus)
1215 per_cpu(cpufreq_cpu_data, j) = policy;
1216 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1218 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1219 policy->cur = cpufreq_driver->get(policy->cpu);
1221 pr_err("%s: ->get() failed\n", __func__);
1227 * Sometimes boot loaders set CPU frequency to a value outside of
1228 * frequency table present with cpufreq core. In such cases CPU might be
1229 * unstable if it has to run on that frequency for long duration of time
1230 * and so its better to set it to a frequency which is specified in
1231 * freq-table. This also makes cpufreq stats inconsistent as
1232 * cpufreq-stats would fail to register because current frequency of CPU
1233 * isn't found in freq-table.
1235 * Because we don't want this change to effect boot process badly, we go
1236 * for the next freq which is >= policy->cur ('cur' must be set by now,
1237 * otherwise we will end up setting freq to lowest of the table as 'cur'
1238 * is initialized to zero).
1240 * We are passing target-freq as "policy->cur - 1" otherwise
1241 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1242 * equal to target-freq.
1244 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1246 /* Are we running at unknown frequency ? */
1247 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1248 if (ret == -EINVAL) {
1249 /* Warn user and fix it */
1250 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1251 __func__, policy->cpu, policy->cur);
1252 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1253 CPUFREQ_RELATION_L);
1256 * Reaching here after boot in a few seconds may not
1257 * mean that system will remain stable at "unknown"
1258 * frequency for longer duration. Hence, a BUG_ON().
1261 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1262 __func__, policy->cpu, policy->cur);
1266 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1267 CPUFREQ_START, policy);
1269 if (!recover_policy) {
1270 ret = cpufreq_add_dev_interface(policy, dev);
1272 goto err_out_unregister;
1273 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1274 CPUFREQ_CREATE_POLICY, policy);
1277 write_lock_irqsave(&cpufreq_driver_lock, flags);
1278 list_add(&policy->policy_list, &cpufreq_policy_list);
1279 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1281 cpufreq_init_policy(policy);
1283 if (!recover_policy) {
1284 policy->user_policy.policy = policy->policy;
1285 policy->user_policy.governor = policy->governor;
1287 up_write(&policy->rwsem);
1289 kobject_uevent(&policy->kobj, KOBJ_ADD);
1290 up_read(&cpufreq_rwsem);
1292 pr_debug("initialization complete\n");
1298 write_lock_irqsave(&cpufreq_driver_lock, flags);
1299 for_each_cpu(j, policy->cpus)
1300 per_cpu(cpufreq_cpu_data, j) = NULL;
1301 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1303 up_write(&policy->rwsem);
1305 if (cpufreq_driver->exit)
1306 cpufreq_driver->exit(policy);
1308 if (recover_policy) {
1309 /* Do not leave stale fallback data behind. */
1310 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1311 cpufreq_policy_put_kobj(policy);
1313 cpufreq_policy_free(policy);
1316 up_read(&cpufreq_rwsem);
1322 * cpufreq_add_dev - add a CPU device
1324 * Adds the cpufreq interface for a CPU device.
1326 * The Oracle says: try running cpufreq registration/unregistration concurrently
1327 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1328 * mess up, but more thorough testing is needed. - Mathieu
1330 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1332 return __cpufreq_add_dev(dev, sif);
1335 static int __cpufreq_remove_dev_prepare(struct device *dev,
1336 struct subsys_interface *sif)
1338 unsigned int cpu = dev->id, cpus;
1340 unsigned long flags;
1341 struct cpufreq_policy *policy;
1343 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1345 write_lock_irqsave(&cpufreq_driver_lock, flags);
1347 policy = per_cpu(cpufreq_cpu_data, cpu);
1349 /* Save the policy somewhere when doing a light-weight tear-down */
1350 if (cpufreq_suspended)
1351 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1353 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1356 pr_debug("%s: No cpu_data found\n", __func__);
1361 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1363 pr_err("%s: Failed to stop governor\n", __func__);
1368 if (!cpufreq_driver->setpolicy)
1369 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1370 policy->governor->name, CPUFREQ_NAME_LEN);
1372 down_read(&policy->rwsem);
1373 cpus = cpumask_weight(policy->cpus);
1374 up_read(&policy->rwsem);
1376 if (cpu != policy->cpu) {
1377 sysfs_remove_link(&dev->kobj, "cpufreq");
1378 } else if (cpus > 1) {
1379 /* Nominate new CPU */
1380 int new_cpu = cpumask_any_but(policy->cpus, cpu);
1381 struct device *cpu_dev = get_cpu_device(new_cpu);
1383 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1384 ret = update_policy_cpu(policy, new_cpu, cpu_dev);
1386 if (sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1388 pr_err("%s: Failed to restore kobj link to cpu:%d\n",
1389 __func__, cpu_dev->id);
1393 if (!cpufreq_suspended)
1394 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1395 __func__, new_cpu, cpu);
1396 } else if (cpufreq_driver->stop_cpu) {
1397 cpufreq_driver->stop_cpu(policy);
1403 static int __cpufreq_remove_dev_finish(struct device *dev,
1404 struct subsys_interface *sif)
1406 unsigned int cpu = dev->id, cpus;
1408 unsigned long flags;
1409 struct cpufreq_policy *policy;
1411 read_lock_irqsave(&cpufreq_driver_lock, flags);
1412 policy = per_cpu(cpufreq_cpu_data, cpu);
1413 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1416 pr_debug("%s: No cpu_data found\n", __func__);
1420 down_write(&policy->rwsem);
1421 cpus = cpumask_weight(policy->cpus);
1424 cpumask_clear_cpu(cpu, policy->cpus);
1425 up_write(&policy->rwsem);
1427 /* If cpu is last user of policy, free policy */
1430 ret = __cpufreq_governor(policy,
1431 CPUFREQ_GOV_POLICY_EXIT);
1433 pr_err("%s: Failed to exit governor\n",
1439 if (!cpufreq_suspended)
1440 cpufreq_policy_put_kobj(policy);
1443 * Perform the ->exit() even during light-weight tear-down,
1444 * since this is a core component, and is essential for the
1445 * subsequent light-weight ->init() to succeed.
1447 if (cpufreq_driver->exit)
1448 cpufreq_driver->exit(policy);
1450 /* Remove policy from list of active policies */
1451 write_lock_irqsave(&cpufreq_driver_lock, flags);
1452 list_del(&policy->policy_list);
1453 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1455 if (!cpufreq_suspended)
1456 cpufreq_policy_free(policy);
1457 } else if (has_target()) {
1458 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1460 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1463 pr_err("%s: Failed to start governor\n", __func__);
1468 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1473 * cpufreq_remove_dev - remove a CPU device
1475 * Removes the cpufreq interface for a CPU device.
1477 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1479 unsigned int cpu = dev->id;
1482 if (cpu_is_offline(cpu))
1485 ret = __cpufreq_remove_dev_prepare(dev, sif);
1488 ret = __cpufreq_remove_dev_finish(dev, sif);
1493 static void handle_update(struct work_struct *work)
1495 struct cpufreq_policy *policy =
1496 container_of(work, struct cpufreq_policy, update);
1497 unsigned int cpu = policy->cpu;
1498 pr_debug("handle_update for cpu %u called\n", cpu);
1499 cpufreq_update_policy(cpu);
1503 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1506 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1507 * @new_freq: CPU frequency the CPU actually runs at
1509 * We adjust to current frequency first, and need to clean up later.
1510 * So either call to cpufreq_update_policy() or schedule handle_update()).
1512 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1513 unsigned int new_freq)
1515 struct cpufreq_policy *policy;
1516 struct cpufreq_freqs freqs;
1517 unsigned long flags;
1519 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1520 old_freq, new_freq);
1522 freqs.old = old_freq;
1523 freqs.new = new_freq;
1525 read_lock_irqsave(&cpufreq_driver_lock, flags);
1526 policy = per_cpu(cpufreq_cpu_data, cpu);
1527 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
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(unsigned int cpu)
1580 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1581 unsigned int ret_freq = 0;
1583 if (!cpufreq_driver->get)
1586 ret_freq = cpufreq_driver->get(cpu);
1588 if (ret_freq && policy->cur &&
1589 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1590 /* verify no discrepancy between actual and
1591 saved value exists */
1592 if (unlikely(ret_freq != policy->cur)) {
1593 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1594 schedule_work(&policy->update);
1602 * cpufreq_get - get the current CPU frequency (in kHz)
1605 * Get the CPU current (static) CPU frequency
1607 unsigned int cpufreq_get(unsigned int cpu)
1609 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1610 unsigned int ret_freq = 0;
1613 down_read(&policy->rwsem);
1614 ret_freq = __cpufreq_get(cpu);
1615 up_read(&policy->rwsem);
1617 cpufreq_cpu_put(policy);
1622 EXPORT_SYMBOL(cpufreq_get);
1624 static struct subsys_interface cpufreq_interface = {
1626 .subsys = &cpu_subsys,
1627 .add_dev = cpufreq_add_dev,
1628 .remove_dev = cpufreq_remove_dev,
1632 * In case platform wants some specific frequency to be configured
1635 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1639 if (!policy->suspend_freq) {
1640 pr_err("%s: suspend_freq can't be zero\n", __func__);
1644 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1645 policy->suspend_freq);
1647 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1648 CPUFREQ_RELATION_H);
1650 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1651 __func__, policy->suspend_freq, ret);
1655 EXPORT_SYMBOL(cpufreq_generic_suspend);
1658 * cpufreq_suspend() - Suspend CPUFreq governors
1660 * Called during system wide Suspend/Hibernate cycles for suspending governors
1661 * as some platforms can't change frequency after this point in suspend cycle.
1662 * Because some of the devices (like: i2c, regulators, etc) they use for
1663 * changing frequency are suspended quickly after this point.
1665 void cpufreq_suspend(void)
1667 struct cpufreq_policy *policy;
1669 if (!cpufreq_driver)
1675 pr_debug("%s: Suspending Governors\n", __func__);
1677 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1678 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1679 pr_err("%s: Failed to stop governor for policy: %p\n",
1681 else if (cpufreq_driver->suspend
1682 && cpufreq_driver->suspend(policy))
1683 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1688 cpufreq_suspended = true;
1692 * cpufreq_resume() - Resume CPUFreq governors
1694 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1695 * are suspended with cpufreq_suspend().
1697 void cpufreq_resume(void)
1699 struct cpufreq_policy *policy;
1701 if (!cpufreq_driver)
1704 cpufreq_suspended = false;
1709 pr_debug("%s: Resuming Governors\n", __func__);
1711 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1712 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1713 pr_err("%s: Failed to resume driver: %p\n", __func__,
1715 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1716 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1717 pr_err("%s: Failed to start governor for policy: %p\n",
1721 * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1722 * policy in list. It will verify that the current freq is in
1723 * sync with what we believe it to be.
1725 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1726 schedule_work(&policy->update);
1731 * cpufreq_get_current_driver - return current driver's name
1733 * Return the name string of the currently loaded cpufreq driver
1736 const char *cpufreq_get_current_driver(void)
1739 return cpufreq_driver->name;
1743 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1746 * cpufreq_get_driver_data - return current driver data
1748 * Return the private data of the currently loaded cpufreq
1749 * driver, or NULL if no cpufreq driver is loaded.
1751 void *cpufreq_get_driver_data(void)
1754 return cpufreq_driver->driver_data;
1758 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1760 /*********************************************************************
1761 * NOTIFIER LISTS INTERFACE *
1762 *********************************************************************/
1765 * cpufreq_register_notifier - register a driver with cpufreq
1766 * @nb: notifier function to register
1767 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1769 * Add a driver to one of two lists: either a list of drivers that
1770 * are notified about clock rate changes (once before and once after
1771 * the transition), or a list of drivers that are notified about
1772 * changes in cpufreq policy.
1774 * This function may sleep, and has the same return conditions as
1775 * blocking_notifier_chain_register.
1777 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1781 if (cpufreq_disabled())
1784 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1787 case CPUFREQ_TRANSITION_NOTIFIER:
1788 ret = srcu_notifier_chain_register(
1789 &cpufreq_transition_notifier_list, nb);
1791 case CPUFREQ_POLICY_NOTIFIER:
1792 ret = blocking_notifier_chain_register(
1793 &cpufreq_policy_notifier_list, nb);
1801 EXPORT_SYMBOL(cpufreq_register_notifier);
1804 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1805 * @nb: notifier block to be unregistered
1806 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1808 * Remove a driver from the CPU frequency notifier list.
1810 * This function may sleep, and has the same return conditions as
1811 * blocking_notifier_chain_unregister.
1813 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1817 if (cpufreq_disabled())
1821 case CPUFREQ_TRANSITION_NOTIFIER:
1822 ret = srcu_notifier_chain_unregister(
1823 &cpufreq_transition_notifier_list, nb);
1825 case CPUFREQ_POLICY_NOTIFIER:
1826 ret = blocking_notifier_chain_unregister(
1827 &cpufreq_policy_notifier_list, nb);
1835 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1838 /*********************************************************************
1840 *********************************************************************/
1842 /* Must set freqs->new to intermediate frequency */
1843 static int __target_intermediate(struct cpufreq_policy *policy,
1844 struct cpufreq_freqs *freqs, int index)
1848 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1850 /* We don't need to switch to intermediate freq */
1854 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1855 __func__, policy->cpu, freqs->old, freqs->new);
1857 cpufreq_freq_transition_begin(policy, freqs);
1858 ret = cpufreq_driver->target_intermediate(policy, index);
1859 cpufreq_freq_transition_end(policy, freqs, ret);
1862 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1868 static int __target_index(struct cpufreq_policy *policy,
1869 struct cpufreq_frequency_table *freq_table, int index)
1871 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1872 unsigned int intermediate_freq = 0;
1873 int retval = -EINVAL;
1876 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1878 /* Handle switching to intermediate frequency */
1879 if (cpufreq_driver->get_intermediate) {
1880 retval = __target_intermediate(policy, &freqs, index);
1884 intermediate_freq = freqs.new;
1885 /* Set old freq to intermediate */
1886 if (intermediate_freq)
1887 freqs.old = freqs.new;
1890 freqs.new = freq_table[index].frequency;
1891 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1892 __func__, policy->cpu, freqs.old, freqs.new);
1894 cpufreq_freq_transition_begin(policy, &freqs);
1897 retval = cpufreq_driver->target_index(policy, index);
1899 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1903 cpufreq_freq_transition_end(policy, &freqs, retval);
1906 * Failed after setting to intermediate freq? Driver should have
1907 * reverted back to initial frequency and so should we. Check
1908 * here for intermediate_freq instead of get_intermediate, in
1909 * case we have't switched to intermediate freq at all.
1911 if (unlikely(retval && intermediate_freq)) {
1912 freqs.old = intermediate_freq;
1913 freqs.new = policy->restore_freq;
1914 cpufreq_freq_transition_begin(policy, &freqs);
1915 cpufreq_freq_transition_end(policy, &freqs, 0);
1922 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1923 unsigned int target_freq,
1924 unsigned int relation)
1926 unsigned int old_target_freq = target_freq;
1927 int retval = -EINVAL;
1929 if (cpufreq_disabled())
1932 /* Make sure that target_freq is within supported range */
1933 if (target_freq > policy->max)
1934 target_freq = policy->max;
1935 if (target_freq < policy->min)
1936 target_freq = policy->min;
1938 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1939 policy->cpu, target_freq, relation, old_target_freq);
1942 * This might look like a redundant call as we are checking it again
1943 * after finding index. But it is left intentionally for cases where
1944 * exactly same freq is called again and so we can save on few function
1947 if (target_freq == policy->cur)
1950 /* Save last value to restore later on errors */
1951 policy->restore_freq = policy->cur;
1953 if (cpufreq_driver->target)
1954 retval = cpufreq_driver->target(policy, target_freq, relation);
1955 else if (cpufreq_driver->target_index) {
1956 struct cpufreq_frequency_table *freq_table;
1959 freq_table = cpufreq_frequency_get_table(policy->cpu);
1960 if (unlikely(!freq_table)) {
1961 pr_err("%s: Unable to find freq_table\n", __func__);
1965 retval = cpufreq_frequency_table_target(policy, freq_table,
1966 target_freq, relation, &index);
1967 if (unlikely(retval)) {
1968 pr_err("%s: Unable to find matching freq\n", __func__);
1972 if (freq_table[index].frequency == policy->cur) {
1977 retval = __target_index(policy, freq_table, index);
1983 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1985 int cpufreq_driver_target(struct cpufreq_policy *policy,
1986 unsigned int target_freq,
1987 unsigned int relation)
1991 down_write(&policy->rwsem);
1993 ret = __cpufreq_driver_target(policy, target_freq, relation);
1995 up_write(&policy->rwsem);
1999 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2002 * when "event" is CPUFREQ_GOV_LIMITS
2005 static int __cpufreq_governor(struct cpufreq_policy *policy,
2010 /* Only must be defined when default governor is known to have latency
2011 restrictions, like e.g. conservative or ondemand.
2012 That this is the case is already ensured in Kconfig
2014 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2015 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2017 struct cpufreq_governor *gov = NULL;
2020 /* Don't start any governor operations if we are entering suspend */
2021 if (cpufreq_suspended)
2024 if (policy->governor->max_transition_latency &&
2025 policy->cpuinfo.transition_latency >
2026 policy->governor->max_transition_latency) {
2030 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2031 policy->governor->name, gov->name);
2032 policy->governor = gov;
2036 if (event == CPUFREQ_GOV_POLICY_INIT)
2037 if (!try_module_get(policy->governor->owner))
2040 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2041 policy->cpu, event);
2043 mutex_lock(&cpufreq_governor_lock);
2044 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2045 || (!policy->governor_enabled
2046 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2047 mutex_unlock(&cpufreq_governor_lock);
2051 if (event == CPUFREQ_GOV_STOP)
2052 policy->governor_enabled = false;
2053 else if (event == CPUFREQ_GOV_START)
2054 policy->governor_enabled = true;
2056 mutex_unlock(&cpufreq_governor_lock);
2058 ret = policy->governor->governor(policy, event);
2061 if (event == CPUFREQ_GOV_POLICY_INIT)
2062 policy->governor->initialized++;
2063 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2064 policy->governor->initialized--;
2066 /* Restore original values */
2067 mutex_lock(&cpufreq_governor_lock);
2068 if (event == CPUFREQ_GOV_STOP)
2069 policy->governor_enabled = true;
2070 else if (event == CPUFREQ_GOV_START)
2071 policy->governor_enabled = false;
2072 mutex_unlock(&cpufreq_governor_lock);
2075 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2076 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2077 module_put(policy->governor->owner);
2082 int cpufreq_register_governor(struct cpufreq_governor *governor)
2089 if (cpufreq_disabled())
2092 mutex_lock(&cpufreq_governor_mutex);
2094 governor->initialized = 0;
2096 if (__find_governor(governor->name) == NULL) {
2098 list_add(&governor->governor_list, &cpufreq_governor_list);
2101 mutex_unlock(&cpufreq_governor_mutex);
2104 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2106 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2113 if (cpufreq_disabled())
2116 for_each_present_cpu(cpu) {
2117 if (cpu_online(cpu))
2119 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2120 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2123 mutex_lock(&cpufreq_governor_mutex);
2124 list_del(&governor->governor_list);
2125 mutex_unlock(&cpufreq_governor_mutex);
2128 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2131 /*********************************************************************
2132 * POLICY INTERFACE *
2133 *********************************************************************/
2136 * cpufreq_get_policy - get the current cpufreq_policy
2137 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2140 * Reads the current cpufreq policy.
2142 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2144 struct cpufreq_policy *cpu_policy;
2148 cpu_policy = cpufreq_cpu_get(cpu);
2152 memcpy(policy, cpu_policy, sizeof(*policy));
2154 cpufreq_cpu_put(cpu_policy);
2157 EXPORT_SYMBOL(cpufreq_get_policy);
2160 * policy : current policy.
2161 * new_policy: policy to be set.
2163 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2164 struct cpufreq_policy *new_policy)
2166 struct cpufreq_governor *old_gov;
2169 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2170 new_policy->cpu, new_policy->min, new_policy->max);
2172 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2174 if (new_policy->min > policy->max || new_policy->max < policy->min)
2177 /* verify the cpu speed can be set within this limit */
2178 ret = cpufreq_driver->verify(new_policy);
2182 /* adjust if necessary - all reasons */
2183 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2184 CPUFREQ_ADJUST, new_policy);
2186 /* adjust if necessary - hardware incompatibility*/
2187 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2188 CPUFREQ_INCOMPATIBLE, new_policy);
2191 * verify the cpu speed can be set within this limit, which might be
2192 * different to the first one
2194 ret = cpufreq_driver->verify(new_policy);
2198 /* notification of the new policy */
2199 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2200 CPUFREQ_NOTIFY, new_policy);
2202 policy->min = new_policy->min;
2203 policy->max = new_policy->max;
2205 pr_debug("new min and max freqs are %u - %u kHz\n",
2206 policy->min, policy->max);
2208 if (cpufreq_driver->setpolicy) {
2209 policy->policy = new_policy->policy;
2210 pr_debug("setting range\n");
2211 return cpufreq_driver->setpolicy(new_policy);
2214 if (new_policy->governor == policy->governor)
2217 pr_debug("governor switch\n");
2219 /* save old, working values */
2220 old_gov = policy->governor;
2221 /* end old governor */
2223 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2224 up_write(&policy->rwsem);
2225 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2226 down_write(&policy->rwsem);
2229 /* start new governor */
2230 policy->governor = new_policy->governor;
2231 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2232 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2235 up_write(&policy->rwsem);
2236 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2237 down_write(&policy->rwsem);
2240 /* new governor failed, so re-start old one */
2241 pr_debug("starting governor %s failed\n", policy->governor->name);
2243 policy->governor = old_gov;
2244 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2245 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2251 pr_debug("governor: change or update limits\n");
2252 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2256 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2257 * @cpu: CPU which shall be re-evaluated
2259 * Useful for policy notifiers which have different necessities
2260 * at different times.
2262 int cpufreq_update_policy(unsigned int cpu)
2264 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2265 struct cpufreq_policy new_policy;
2271 down_write(&policy->rwsem);
2273 pr_debug("updating policy for CPU %u\n", cpu);
2274 memcpy(&new_policy, policy, sizeof(*policy));
2275 new_policy.min = policy->user_policy.min;
2276 new_policy.max = policy->user_policy.max;
2277 new_policy.policy = policy->user_policy.policy;
2278 new_policy.governor = policy->user_policy.governor;
2281 * BIOS might change freq behind our back
2282 * -> ask driver for current freq and notify governors about a change
2284 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2285 new_policy.cur = cpufreq_driver->get(cpu);
2286 if (WARN_ON(!new_policy.cur)) {
2292 pr_debug("Driver did not initialize current freq\n");
2293 policy->cur = new_policy.cur;
2295 if (policy->cur != new_policy.cur && has_target())
2296 cpufreq_out_of_sync(cpu, policy->cur,
2301 ret = cpufreq_set_policy(policy, &new_policy);
2304 up_write(&policy->rwsem);
2306 cpufreq_cpu_put(policy);
2309 EXPORT_SYMBOL(cpufreq_update_policy);
2311 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2312 unsigned long action, void *hcpu)
2314 unsigned int cpu = (unsigned long)hcpu;
2317 dev = get_cpu_device(cpu);
2319 switch (action & ~CPU_TASKS_FROZEN) {
2321 __cpufreq_add_dev(dev, NULL);
2324 case CPU_DOWN_PREPARE:
2325 __cpufreq_remove_dev_prepare(dev, NULL);
2329 __cpufreq_remove_dev_finish(dev, NULL);
2332 case CPU_DOWN_FAILED:
2333 __cpufreq_add_dev(dev, NULL);
2340 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2341 .notifier_call = cpufreq_cpu_callback,
2344 /*********************************************************************
2346 *********************************************************************/
2347 static int cpufreq_boost_set_sw(int state)
2349 struct cpufreq_frequency_table *freq_table;
2350 struct cpufreq_policy *policy;
2353 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2354 freq_table = cpufreq_frequency_get_table(policy->cpu);
2356 ret = cpufreq_frequency_table_cpuinfo(policy,
2359 pr_err("%s: Policy frequency update failed\n",
2363 policy->user_policy.max = policy->max;
2364 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2371 int cpufreq_boost_trigger_state(int state)
2373 unsigned long flags;
2376 if (cpufreq_driver->boost_enabled == state)
2379 write_lock_irqsave(&cpufreq_driver_lock, flags);
2380 cpufreq_driver->boost_enabled = state;
2381 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2383 ret = cpufreq_driver->set_boost(state);
2385 write_lock_irqsave(&cpufreq_driver_lock, flags);
2386 cpufreq_driver->boost_enabled = !state;
2387 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2389 pr_err("%s: Cannot %s BOOST\n",
2390 __func__, state ? "enable" : "disable");
2396 int cpufreq_boost_supported(void)
2398 if (likely(cpufreq_driver))
2399 return cpufreq_driver->boost_supported;
2403 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2405 int cpufreq_boost_enabled(void)
2407 return cpufreq_driver->boost_enabled;
2409 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2411 /*********************************************************************
2412 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2413 *********************************************************************/
2416 * cpufreq_register_driver - register a CPU Frequency driver
2417 * @driver_data: A struct cpufreq_driver containing the values#
2418 * submitted by the CPU Frequency driver.
2420 * Registers a CPU Frequency driver to this core code. This code
2421 * returns zero on success, -EBUSY when another driver got here first
2422 * (and isn't unregistered in the meantime).
2425 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2427 unsigned long flags;
2430 if (cpufreq_disabled())
2433 if (!driver_data || !driver_data->verify || !driver_data->init ||
2434 !(driver_data->setpolicy || driver_data->target_index ||
2435 driver_data->target) ||
2436 (driver_data->setpolicy && (driver_data->target_index ||
2437 driver_data->target)) ||
2438 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2441 pr_debug("trying to register driver %s\n", driver_data->name);
2443 if (driver_data->setpolicy)
2444 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2446 write_lock_irqsave(&cpufreq_driver_lock, flags);
2447 if (cpufreq_driver) {
2448 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2451 cpufreq_driver = driver_data;
2452 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2454 if (cpufreq_boost_supported()) {
2456 * Check if driver provides function to enable boost -
2457 * if not, use cpufreq_boost_set_sw as default
2459 if (!cpufreq_driver->set_boost)
2460 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2462 ret = cpufreq_sysfs_create_file(&boost.attr);
2464 pr_err("%s: cannot register global BOOST sysfs file\n",
2466 goto err_null_driver;
2470 ret = subsys_interface_register(&cpufreq_interface);
2472 goto err_boost_unreg;
2474 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2478 /* check for at least one working CPU */
2479 for (i = 0; i < nr_cpu_ids; i++)
2480 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2485 /* if all ->init() calls failed, unregister */
2487 pr_debug("no CPU initialized for driver %s\n",
2493 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2494 pr_debug("driver %s up and running\n", driver_data->name);
2498 subsys_interface_unregister(&cpufreq_interface);
2500 if (cpufreq_boost_supported())
2501 cpufreq_sysfs_remove_file(&boost.attr);
2503 write_lock_irqsave(&cpufreq_driver_lock, flags);
2504 cpufreq_driver = NULL;
2505 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2508 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2511 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2513 * Unregister the current CPUFreq driver. Only call this if you have
2514 * the right to do so, i.e. if you have succeeded in initialising before!
2515 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2516 * currently not initialised.
2518 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2520 unsigned long flags;
2522 if (!cpufreq_driver || (driver != cpufreq_driver))
2525 pr_debug("unregistering driver %s\n", driver->name);
2527 subsys_interface_unregister(&cpufreq_interface);
2528 if (cpufreq_boost_supported())
2529 cpufreq_sysfs_remove_file(&boost.attr);
2531 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2533 down_write(&cpufreq_rwsem);
2534 write_lock_irqsave(&cpufreq_driver_lock, flags);
2536 cpufreq_driver = NULL;
2538 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2539 up_write(&cpufreq_rwsem);
2543 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2545 static int __init cpufreq_core_init(void)
2547 if (cpufreq_disabled())
2550 cpufreq_global_kobject = kobject_create();
2551 BUG_ON(!cpufreq_global_kobject);
2555 core_initcall(cpufreq_core_init);