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);
1026 policy->governor = NULL;
1031 static struct cpufreq_policy *cpufreq_policy_alloc(void)
1033 struct cpufreq_policy *policy;
1035 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1039 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1040 goto err_free_policy;
1042 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1043 goto err_free_cpumask;
1045 INIT_LIST_HEAD(&policy->policy_list);
1046 init_rwsem(&policy->rwsem);
1047 spin_lock_init(&policy->transition_lock);
1048 init_waitqueue_head(&policy->transition_wait);
1053 free_cpumask_var(policy->cpus);
1060 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1062 struct kobject *kobj;
1063 struct completion *cmp;
1065 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1066 CPUFREQ_REMOVE_POLICY, policy);
1068 down_read(&policy->rwsem);
1069 kobj = &policy->kobj;
1070 cmp = &policy->kobj_unregister;
1071 up_read(&policy->rwsem);
1075 * We need to make sure that the underlying kobj is
1076 * actually not referenced anymore by anybody before we
1077 * proceed with unloading.
1079 pr_debug("waiting for dropping of refcount\n");
1080 wait_for_completion(cmp);
1081 pr_debug("wait complete\n");
1084 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1086 free_cpumask_var(policy->related_cpus);
1087 free_cpumask_var(policy->cpus);
1091 static int update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu,
1092 struct device *cpu_dev)
1096 if (WARN_ON(cpu == policy->cpu))
1099 /* Move kobject to the new policy->cpu */
1100 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1102 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1106 down_write(&policy->rwsem);
1108 policy->last_cpu = policy->cpu;
1111 up_write(&policy->rwsem);
1113 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1114 CPUFREQ_UPDATE_POLICY_CPU, policy);
1119 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1121 unsigned int j, cpu = dev->id;
1123 struct cpufreq_policy *policy;
1124 unsigned long flags;
1125 bool recover_policy = cpufreq_suspended;
1126 #ifdef CONFIG_HOTPLUG_CPU
1127 struct cpufreq_policy *tpolicy;
1130 if (cpu_is_offline(cpu))
1133 pr_debug("adding CPU %u\n", cpu);
1136 /* check whether a different CPU already registered this
1137 * CPU because it is in the same boat. */
1138 policy = cpufreq_cpu_get(cpu);
1139 if (unlikely(policy)) {
1140 cpufreq_cpu_put(policy);
1145 if (!down_read_trylock(&cpufreq_rwsem))
1148 #ifdef CONFIG_HOTPLUG_CPU
1149 /* Check if this cpu was hot-unplugged earlier and has siblings */
1150 read_lock_irqsave(&cpufreq_driver_lock, flags);
1151 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1152 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1153 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1154 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1155 up_read(&cpufreq_rwsem);
1159 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1163 * Restore the saved policy when doing light-weight init and fall back
1164 * to the full init if that fails.
1166 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1168 recover_policy = false;
1169 policy = cpufreq_policy_alloc();
1175 * In the resume path, since we restore a saved policy, the assignment
1176 * to policy->cpu is like an update of the existing policy, rather than
1177 * the creation of a brand new one. So we need to perform this update
1178 * by invoking update_policy_cpu().
1180 if (recover_policy && cpu != policy->cpu)
1181 WARN_ON(update_policy_cpu(policy, cpu, dev));
1185 cpumask_copy(policy->cpus, cpumask_of(cpu));
1187 init_completion(&policy->kobj_unregister);
1188 INIT_WORK(&policy->update, handle_update);
1190 /* call driver. From then on the cpufreq must be able
1191 * to accept all calls to ->verify and ->setpolicy for this CPU
1193 ret = cpufreq_driver->init(policy);
1195 pr_debug("initialization failed\n");
1196 goto err_set_policy_cpu;
1199 /* related cpus should atleast have policy->cpus */
1200 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1203 * affected cpus must always be the one, which are online. We aren't
1204 * managing offline cpus here.
1206 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1208 if (!recover_policy) {
1209 policy->user_policy.min = policy->min;
1210 policy->user_policy.max = policy->max;
1213 down_write(&policy->rwsem);
1214 write_lock_irqsave(&cpufreq_driver_lock, flags);
1215 for_each_cpu(j, policy->cpus)
1216 per_cpu(cpufreq_cpu_data, j) = policy;
1217 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1219 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1220 policy->cur = cpufreq_driver->get(policy->cpu);
1222 pr_err("%s: ->get() failed\n", __func__);
1228 * Sometimes boot loaders set CPU frequency to a value outside of
1229 * frequency table present with cpufreq core. In such cases CPU might be
1230 * unstable if it has to run on that frequency for long duration of time
1231 * and so its better to set it to a frequency which is specified in
1232 * freq-table. This also makes cpufreq stats inconsistent as
1233 * cpufreq-stats would fail to register because current frequency of CPU
1234 * isn't found in freq-table.
1236 * Because we don't want this change to effect boot process badly, we go
1237 * for the next freq which is >= policy->cur ('cur' must be set by now,
1238 * otherwise we will end up setting freq to lowest of the table as 'cur'
1239 * is initialized to zero).
1241 * We are passing target-freq as "policy->cur - 1" otherwise
1242 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1243 * equal to target-freq.
1245 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1247 /* Are we running at unknown frequency ? */
1248 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1249 if (ret == -EINVAL) {
1250 /* Warn user and fix it */
1251 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1252 __func__, policy->cpu, policy->cur);
1253 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1254 CPUFREQ_RELATION_L);
1257 * Reaching here after boot in a few seconds may not
1258 * mean that system will remain stable at "unknown"
1259 * frequency for longer duration. Hence, a BUG_ON().
1262 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1263 __func__, policy->cpu, policy->cur);
1267 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1268 CPUFREQ_START, policy);
1270 if (!recover_policy) {
1271 ret = cpufreq_add_dev_interface(policy, dev);
1273 goto err_out_unregister;
1274 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1275 CPUFREQ_CREATE_POLICY, policy);
1278 write_lock_irqsave(&cpufreq_driver_lock, flags);
1279 list_add(&policy->policy_list, &cpufreq_policy_list);
1280 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1282 cpufreq_init_policy(policy);
1284 if (!recover_policy) {
1285 policy->user_policy.policy = policy->policy;
1286 policy->user_policy.governor = policy->governor;
1288 up_write(&policy->rwsem);
1290 kobject_uevent(&policy->kobj, KOBJ_ADD);
1291 up_read(&cpufreq_rwsem);
1293 pr_debug("initialization complete\n");
1299 write_lock_irqsave(&cpufreq_driver_lock, flags);
1300 for_each_cpu(j, policy->cpus)
1301 per_cpu(cpufreq_cpu_data, j) = NULL;
1302 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1304 up_write(&policy->rwsem);
1306 if (cpufreq_driver->exit)
1307 cpufreq_driver->exit(policy);
1309 if (recover_policy) {
1310 /* Do not leave stale fallback data behind. */
1311 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1312 cpufreq_policy_put_kobj(policy);
1314 cpufreq_policy_free(policy);
1317 up_read(&cpufreq_rwsem);
1323 * cpufreq_add_dev - add a CPU device
1325 * Adds the cpufreq interface for a CPU device.
1327 * The Oracle says: try running cpufreq registration/unregistration concurrently
1328 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1329 * mess up, but more thorough testing is needed. - Mathieu
1331 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1333 return __cpufreq_add_dev(dev, sif);
1336 static int __cpufreq_remove_dev_prepare(struct device *dev,
1337 struct subsys_interface *sif)
1339 unsigned int cpu = dev->id, cpus;
1341 unsigned long flags;
1342 struct cpufreq_policy *policy;
1344 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1346 write_lock_irqsave(&cpufreq_driver_lock, flags);
1348 policy = per_cpu(cpufreq_cpu_data, cpu);
1350 /* Save the policy somewhere when doing a light-weight tear-down */
1351 if (cpufreq_suspended)
1352 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1354 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1357 pr_debug("%s: No cpu_data found\n", __func__);
1362 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1364 pr_err("%s: Failed to stop governor\n", __func__);
1369 if (!cpufreq_driver->setpolicy)
1370 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1371 policy->governor->name, CPUFREQ_NAME_LEN);
1373 down_read(&policy->rwsem);
1374 cpus = cpumask_weight(policy->cpus);
1375 up_read(&policy->rwsem);
1377 if (cpu != policy->cpu) {
1378 sysfs_remove_link(&dev->kobj, "cpufreq");
1379 } else if (cpus > 1) {
1380 /* Nominate new CPU */
1381 int new_cpu = cpumask_any_but(policy->cpus, cpu);
1382 struct device *cpu_dev = get_cpu_device(new_cpu);
1384 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1385 ret = update_policy_cpu(policy, new_cpu, cpu_dev);
1387 if (sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1389 pr_err("%s: Failed to restore kobj link to cpu:%d\n",
1390 __func__, cpu_dev->id);
1394 if (!cpufreq_suspended)
1395 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1396 __func__, new_cpu, cpu);
1397 } else if (cpufreq_driver->stop_cpu) {
1398 cpufreq_driver->stop_cpu(policy);
1404 static int __cpufreq_remove_dev_finish(struct device *dev,
1405 struct subsys_interface *sif)
1407 unsigned int cpu = dev->id, cpus;
1409 unsigned long flags;
1410 struct cpufreq_policy *policy;
1412 read_lock_irqsave(&cpufreq_driver_lock, flags);
1413 policy = per_cpu(cpufreq_cpu_data, cpu);
1414 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1417 pr_debug("%s: No cpu_data found\n", __func__);
1421 down_write(&policy->rwsem);
1422 cpus = cpumask_weight(policy->cpus);
1425 cpumask_clear_cpu(cpu, policy->cpus);
1426 up_write(&policy->rwsem);
1428 /* If cpu is last user of policy, free policy */
1431 ret = __cpufreq_governor(policy,
1432 CPUFREQ_GOV_POLICY_EXIT);
1434 pr_err("%s: Failed to exit governor\n",
1440 if (!cpufreq_suspended)
1441 cpufreq_policy_put_kobj(policy);
1444 * Perform the ->exit() even during light-weight tear-down,
1445 * since this is a core component, and is essential for the
1446 * subsequent light-weight ->init() to succeed.
1448 if (cpufreq_driver->exit)
1449 cpufreq_driver->exit(policy);
1451 /* Remove policy from list of active policies */
1452 write_lock_irqsave(&cpufreq_driver_lock, flags);
1453 list_del(&policy->policy_list);
1454 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1456 if (!cpufreq_suspended)
1457 cpufreq_policy_free(policy);
1458 } else if (has_target()) {
1459 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1461 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1464 pr_err("%s: Failed to start governor\n", __func__);
1469 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1474 * cpufreq_remove_dev - remove a CPU device
1476 * Removes the cpufreq interface for a CPU device.
1478 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1480 unsigned int cpu = dev->id;
1483 if (cpu_is_offline(cpu))
1486 ret = __cpufreq_remove_dev_prepare(dev, sif);
1489 ret = __cpufreq_remove_dev_finish(dev, sif);
1494 static void handle_update(struct work_struct *work)
1496 struct cpufreq_policy *policy =
1497 container_of(work, struct cpufreq_policy, update);
1498 unsigned int cpu = policy->cpu;
1499 pr_debug("handle_update for cpu %u called\n", cpu);
1500 cpufreq_update_policy(cpu);
1504 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1507 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1508 * @new_freq: CPU frequency the CPU actually runs at
1510 * We adjust to current frequency first, and need to clean up later.
1511 * So either call to cpufreq_update_policy() or schedule handle_update()).
1513 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1514 unsigned int new_freq)
1516 struct cpufreq_policy *policy;
1517 struct cpufreq_freqs freqs;
1518 unsigned long flags;
1520 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1521 old_freq, new_freq);
1523 freqs.old = old_freq;
1524 freqs.new = new_freq;
1526 read_lock_irqsave(&cpufreq_driver_lock, flags);
1527 policy = per_cpu(cpufreq_cpu_data, cpu);
1528 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1530 cpufreq_freq_transition_begin(policy, &freqs);
1531 cpufreq_freq_transition_end(policy, &freqs, 0);
1535 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1538 * This is the last known freq, without actually getting it from the driver.
1539 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1541 unsigned int cpufreq_quick_get(unsigned int cpu)
1543 struct cpufreq_policy *policy;
1544 unsigned int ret_freq = 0;
1546 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1547 return cpufreq_driver->get(cpu);
1549 policy = cpufreq_cpu_get(cpu);
1551 ret_freq = policy->cur;
1552 cpufreq_cpu_put(policy);
1557 EXPORT_SYMBOL(cpufreq_quick_get);
1560 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1563 * Just return the max possible frequency for a given CPU.
1565 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1567 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1568 unsigned int ret_freq = 0;
1571 ret_freq = policy->max;
1572 cpufreq_cpu_put(policy);
1577 EXPORT_SYMBOL(cpufreq_quick_get_max);
1579 static unsigned int __cpufreq_get(unsigned int cpu)
1581 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1582 unsigned int ret_freq = 0;
1584 if (!cpufreq_driver->get)
1587 ret_freq = cpufreq_driver->get(cpu);
1589 if (ret_freq && policy->cur &&
1590 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1591 /* verify no discrepancy between actual and
1592 saved value exists */
1593 if (unlikely(ret_freq != policy->cur)) {
1594 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1595 schedule_work(&policy->update);
1603 * cpufreq_get - get the current CPU frequency (in kHz)
1606 * Get the CPU current (static) CPU frequency
1608 unsigned int cpufreq_get(unsigned int cpu)
1610 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1611 unsigned int ret_freq = 0;
1614 down_read(&policy->rwsem);
1615 ret_freq = __cpufreq_get(cpu);
1616 up_read(&policy->rwsem);
1618 cpufreq_cpu_put(policy);
1623 EXPORT_SYMBOL(cpufreq_get);
1625 static struct subsys_interface cpufreq_interface = {
1627 .subsys = &cpu_subsys,
1628 .add_dev = cpufreq_add_dev,
1629 .remove_dev = cpufreq_remove_dev,
1633 * In case platform wants some specific frequency to be configured
1636 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1640 if (!policy->suspend_freq) {
1641 pr_err("%s: suspend_freq can't be zero\n", __func__);
1645 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1646 policy->suspend_freq);
1648 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1649 CPUFREQ_RELATION_H);
1651 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1652 __func__, policy->suspend_freq, ret);
1656 EXPORT_SYMBOL(cpufreq_generic_suspend);
1659 * cpufreq_suspend() - Suspend CPUFreq governors
1661 * Called during system wide Suspend/Hibernate cycles for suspending governors
1662 * as some platforms can't change frequency after this point in suspend cycle.
1663 * Because some of the devices (like: i2c, regulators, etc) they use for
1664 * changing frequency are suspended quickly after this point.
1666 void cpufreq_suspend(void)
1668 struct cpufreq_policy *policy;
1670 if (!cpufreq_driver)
1676 pr_debug("%s: Suspending Governors\n", __func__);
1678 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1679 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1680 pr_err("%s: Failed to stop governor for policy: %p\n",
1682 else if (cpufreq_driver->suspend
1683 && cpufreq_driver->suspend(policy))
1684 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1689 cpufreq_suspended = true;
1693 * cpufreq_resume() - Resume CPUFreq governors
1695 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1696 * are suspended with cpufreq_suspend().
1698 void cpufreq_resume(void)
1700 struct cpufreq_policy *policy;
1702 if (!cpufreq_driver)
1705 cpufreq_suspended = false;
1710 pr_debug("%s: Resuming Governors\n", __func__);
1712 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1713 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1714 pr_err("%s: Failed to resume driver: %p\n", __func__,
1716 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1717 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1718 pr_err("%s: Failed to start governor for policy: %p\n",
1722 * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1723 * policy in list. It will verify that the current freq is in
1724 * sync with what we believe it to be.
1726 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1727 schedule_work(&policy->update);
1732 * cpufreq_get_current_driver - return current driver's name
1734 * Return the name string of the currently loaded cpufreq driver
1737 const char *cpufreq_get_current_driver(void)
1740 return cpufreq_driver->name;
1744 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1747 * cpufreq_get_driver_data - return current driver data
1749 * Return the private data of the currently loaded cpufreq
1750 * driver, or NULL if no cpufreq driver is loaded.
1752 void *cpufreq_get_driver_data(void)
1755 return cpufreq_driver->driver_data;
1759 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1761 /*********************************************************************
1762 * NOTIFIER LISTS INTERFACE *
1763 *********************************************************************/
1766 * cpufreq_register_notifier - register a driver with cpufreq
1767 * @nb: notifier function to register
1768 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1770 * Add a driver to one of two lists: either a list of drivers that
1771 * are notified about clock rate changes (once before and once after
1772 * the transition), or a list of drivers that are notified about
1773 * changes in cpufreq policy.
1775 * This function may sleep, and has the same return conditions as
1776 * blocking_notifier_chain_register.
1778 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1782 if (cpufreq_disabled())
1785 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1788 case CPUFREQ_TRANSITION_NOTIFIER:
1789 ret = srcu_notifier_chain_register(
1790 &cpufreq_transition_notifier_list, nb);
1792 case CPUFREQ_POLICY_NOTIFIER:
1793 ret = blocking_notifier_chain_register(
1794 &cpufreq_policy_notifier_list, nb);
1802 EXPORT_SYMBOL(cpufreq_register_notifier);
1805 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1806 * @nb: notifier block to be unregistered
1807 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1809 * Remove a driver from the CPU frequency notifier list.
1811 * This function may sleep, and has the same return conditions as
1812 * blocking_notifier_chain_unregister.
1814 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1818 if (cpufreq_disabled())
1822 case CPUFREQ_TRANSITION_NOTIFIER:
1823 ret = srcu_notifier_chain_unregister(
1824 &cpufreq_transition_notifier_list, nb);
1826 case CPUFREQ_POLICY_NOTIFIER:
1827 ret = blocking_notifier_chain_unregister(
1828 &cpufreq_policy_notifier_list, nb);
1836 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1839 /*********************************************************************
1841 *********************************************************************/
1843 /* Must set freqs->new to intermediate frequency */
1844 static int __target_intermediate(struct cpufreq_policy *policy,
1845 struct cpufreq_freqs *freqs, int index)
1849 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1851 /* We don't need to switch to intermediate freq */
1855 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1856 __func__, policy->cpu, freqs->old, freqs->new);
1858 cpufreq_freq_transition_begin(policy, freqs);
1859 ret = cpufreq_driver->target_intermediate(policy, index);
1860 cpufreq_freq_transition_end(policy, freqs, ret);
1863 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1869 static int __target_index(struct cpufreq_policy *policy,
1870 struct cpufreq_frequency_table *freq_table, int index)
1872 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1873 unsigned int intermediate_freq = 0;
1874 int retval = -EINVAL;
1877 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1879 /* Handle switching to intermediate frequency */
1880 if (cpufreq_driver->get_intermediate) {
1881 retval = __target_intermediate(policy, &freqs, index);
1885 intermediate_freq = freqs.new;
1886 /* Set old freq to intermediate */
1887 if (intermediate_freq)
1888 freqs.old = freqs.new;
1891 freqs.new = freq_table[index].frequency;
1892 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1893 __func__, policy->cpu, freqs.old, freqs.new);
1895 cpufreq_freq_transition_begin(policy, &freqs);
1898 retval = cpufreq_driver->target_index(policy, index);
1900 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1904 cpufreq_freq_transition_end(policy, &freqs, retval);
1907 * Failed after setting to intermediate freq? Driver should have
1908 * reverted back to initial frequency and so should we. Check
1909 * here for intermediate_freq instead of get_intermediate, in
1910 * case we have't switched to intermediate freq at all.
1912 if (unlikely(retval && intermediate_freq)) {
1913 freqs.old = intermediate_freq;
1914 freqs.new = policy->restore_freq;
1915 cpufreq_freq_transition_begin(policy, &freqs);
1916 cpufreq_freq_transition_end(policy, &freqs, 0);
1923 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1924 unsigned int target_freq,
1925 unsigned int relation)
1927 unsigned int old_target_freq = target_freq;
1928 int retval = -EINVAL;
1930 if (cpufreq_disabled())
1933 /* Make sure that target_freq is within supported range */
1934 if (target_freq > policy->max)
1935 target_freq = policy->max;
1936 if (target_freq < policy->min)
1937 target_freq = policy->min;
1939 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1940 policy->cpu, target_freq, relation, old_target_freq);
1943 * This might look like a redundant call as we are checking it again
1944 * after finding index. But it is left intentionally for cases where
1945 * exactly same freq is called again and so we can save on few function
1948 if (target_freq == policy->cur)
1951 /* Save last value to restore later on errors */
1952 policy->restore_freq = policy->cur;
1954 if (cpufreq_driver->target)
1955 retval = cpufreq_driver->target(policy, target_freq, relation);
1956 else if (cpufreq_driver->target_index) {
1957 struct cpufreq_frequency_table *freq_table;
1960 freq_table = cpufreq_frequency_get_table(policy->cpu);
1961 if (unlikely(!freq_table)) {
1962 pr_err("%s: Unable to find freq_table\n", __func__);
1966 retval = cpufreq_frequency_table_target(policy, freq_table,
1967 target_freq, relation, &index);
1968 if (unlikely(retval)) {
1969 pr_err("%s: Unable to find matching freq\n", __func__);
1973 if (freq_table[index].frequency == policy->cur) {
1978 retval = __target_index(policy, freq_table, index);
1984 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1986 int cpufreq_driver_target(struct cpufreq_policy *policy,
1987 unsigned int target_freq,
1988 unsigned int relation)
1992 down_write(&policy->rwsem);
1994 ret = __cpufreq_driver_target(policy, target_freq, relation);
1996 up_write(&policy->rwsem);
2000 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2003 * when "event" is CPUFREQ_GOV_LIMITS
2006 static int __cpufreq_governor(struct cpufreq_policy *policy,
2011 /* Only must be defined when default governor is known to have latency
2012 restrictions, like e.g. conservative or ondemand.
2013 That this is the case is already ensured in Kconfig
2015 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2016 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2018 struct cpufreq_governor *gov = NULL;
2021 /* Don't start any governor operations if we are entering suspend */
2022 if (cpufreq_suspended)
2025 if (policy->governor->max_transition_latency &&
2026 policy->cpuinfo.transition_latency >
2027 policy->governor->max_transition_latency) {
2031 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2032 policy->governor->name, gov->name);
2033 policy->governor = gov;
2037 if (event == CPUFREQ_GOV_POLICY_INIT)
2038 if (!try_module_get(policy->governor->owner))
2041 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2042 policy->cpu, event);
2044 mutex_lock(&cpufreq_governor_lock);
2045 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2046 || (!policy->governor_enabled
2047 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2048 mutex_unlock(&cpufreq_governor_lock);
2052 if (event == CPUFREQ_GOV_STOP)
2053 policy->governor_enabled = false;
2054 else if (event == CPUFREQ_GOV_START)
2055 policy->governor_enabled = true;
2057 mutex_unlock(&cpufreq_governor_lock);
2059 ret = policy->governor->governor(policy, event);
2062 if (event == CPUFREQ_GOV_POLICY_INIT)
2063 policy->governor->initialized++;
2064 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2065 policy->governor->initialized--;
2067 /* Restore original values */
2068 mutex_lock(&cpufreq_governor_lock);
2069 if (event == CPUFREQ_GOV_STOP)
2070 policy->governor_enabled = true;
2071 else if (event == CPUFREQ_GOV_START)
2072 policy->governor_enabled = false;
2073 mutex_unlock(&cpufreq_governor_lock);
2076 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2077 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2078 module_put(policy->governor->owner);
2083 int cpufreq_register_governor(struct cpufreq_governor *governor)
2090 if (cpufreq_disabled())
2093 mutex_lock(&cpufreq_governor_mutex);
2095 governor->initialized = 0;
2097 if (__find_governor(governor->name) == NULL) {
2099 list_add(&governor->governor_list, &cpufreq_governor_list);
2102 mutex_unlock(&cpufreq_governor_mutex);
2105 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2107 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2114 if (cpufreq_disabled())
2117 for_each_present_cpu(cpu) {
2118 if (cpu_online(cpu))
2120 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2121 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2124 mutex_lock(&cpufreq_governor_mutex);
2125 list_del(&governor->governor_list);
2126 mutex_unlock(&cpufreq_governor_mutex);
2129 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2132 /*********************************************************************
2133 * POLICY INTERFACE *
2134 *********************************************************************/
2137 * cpufreq_get_policy - get the current cpufreq_policy
2138 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2141 * Reads the current cpufreq policy.
2143 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2145 struct cpufreq_policy *cpu_policy;
2149 cpu_policy = cpufreq_cpu_get(cpu);
2153 memcpy(policy, cpu_policy, sizeof(*policy));
2155 cpufreq_cpu_put(cpu_policy);
2158 EXPORT_SYMBOL(cpufreq_get_policy);
2161 * policy : current policy.
2162 * new_policy: policy to be set.
2164 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2165 struct cpufreq_policy *new_policy)
2167 struct cpufreq_governor *old_gov;
2170 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2171 new_policy->cpu, new_policy->min, new_policy->max);
2173 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2175 if (new_policy->min > policy->max || new_policy->max < policy->min)
2178 /* verify the cpu speed can be set within this limit */
2179 ret = cpufreq_driver->verify(new_policy);
2183 /* adjust if necessary - all reasons */
2184 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2185 CPUFREQ_ADJUST, new_policy);
2187 /* adjust if necessary - hardware incompatibility*/
2188 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2189 CPUFREQ_INCOMPATIBLE, new_policy);
2192 * verify the cpu speed can be set within this limit, which might be
2193 * different to the first one
2195 ret = cpufreq_driver->verify(new_policy);
2199 /* notification of the new policy */
2200 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2201 CPUFREQ_NOTIFY, new_policy);
2203 policy->min = new_policy->min;
2204 policy->max = new_policy->max;
2206 pr_debug("new min and max freqs are %u - %u kHz\n",
2207 policy->min, policy->max);
2209 if (cpufreq_driver->setpolicy) {
2210 policy->policy = new_policy->policy;
2211 pr_debug("setting range\n");
2212 return cpufreq_driver->setpolicy(new_policy);
2215 if (new_policy->governor == policy->governor)
2218 pr_debug("governor switch\n");
2220 /* save old, working values */
2221 old_gov = policy->governor;
2222 /* end old governor */
2224 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2225 up_write(&policy->rwsem);
2226 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2227 down_write(&policy->rwsem);
2230 /* start new governor */
2231 policy->governor = new_policy->governor;
2232 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2233 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2236 up_write(&policy->rwsem);
2237 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2238 down_write(&policy->rwsem);
2241 /* new governor failed, so re-start old one */
2242 pr_debug("starting governor %s failed\n", policy->governor->name);
2244 policy->governor = old_gov;
2245 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2246 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2252 pr_debug("governor: change or update limits\n");
2253 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2257 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2258 * @cpu: CPU which shall be re-evaluated
2260 * Useful for policy notifiers which have different necessities
2261 * at different times.
2263 int cpufreq_update_policy(unsigned int cpu)
2265 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2266 struct cpufreq_policy new_policy;
2272 down_write(&policy->rwsem);
2274 pr_debug("updating policy for CPU %u\n", cpu);
2275 memcpy(&new_policy, policy, sizeof(*policy));
2276 new_policy.min = policy->user_policy.min;
2277 new_policy.max = policy->user_policy.max;
2278 new_policy.policy = policy->user_policy.policy;
2279 new_policy.governor = policy->user_policy.governor;
2282 * BIOS might change freq behind our back
2283 * -> ask driver for current freq and notify governors about a change
2285 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2286 new_policy.cur = cpufreq_driver->get(cpu);
2287 if (WARN_ON(!new_policy.cur)) {
2293 pr_debug("Driver did not initialize current freq\n");
2294 policy->cur = new_policy.cur;
2296 if (policy->cur != new_policy.cur && has_target())
2297 cpufreq_out_of_sync(cpu, policy->cur,
2302 ret = cpufreq_set_policy(policy, &new_policy);
2305 up_write(&policy->rwsem);
2307 cpufreq_cpu_put(policy);
2310 EXPORT_SYMBOL(cpufreq_update_policy);
2312 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2313 unsigned long action, void *hcpu)
2315 unsigned int cpu = (unsigned long)hcpu;
2318 dev = get_cpu_device(cpu);
2320 switch (action & ~CPU_TASKS_FROZEN) {
2322 __cpufreq_add_dev(dev, NULL);
2325 case CPU_DOWN_PREPARE:
2326 __cpufreq_remove_dev_prepare(dev, NULL);
2330 __cpufreq_remove_dev_finish(dev, NULL);
2333 case CPU_DOWN_FAILED:
2334 __cpufreq_add_dev(dev, NULL);
2341 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2342 .notifier_call = cpufreq_cpu_callback,
2345 /*********************************************************************
2347 *********************************************************************/
2348 static int cpufreq_boost_set_sw(int state)
2350 struct cpufreq_frequency_table *freq_table;
2351 struct cpufreq_policy *policy;
2354 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2355 freq_table = cpufreq_frequency_get_table(policy->cpu);
2357 ret = cpufreq_frequency_table_cpuinfo(policy,
2360 pr_err("%s: Policy frequency update failed\n",
2364 policy->user_policy.max = policy->max;
2365 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2372 int cpufreq_boost_trigger_state(int state)
2374 unsigned long flags;
2377 if (cpufreq_driver->boost_enabled == state)
2380 write_lock_irqsave(&cpufreq_driver_lock, flags);
2381 cpufreq_driver->boost_enabled = state;
2382 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2384 ret = cpufreq_driver->set_boost(state);
2386 write_lock_irqsave(&cpufreq_driver_lock, flags);
2387 cpufreq_driver->boost_enabled = !state;
2388 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2390 pr_err("%s: Cannot %s BOOST\n",
2391 __func__, state ? "enable" : "disable");
2397 int cpufreq_boost_supported(void)
2399 if (likely(cpufreq_driver))
2400 return cpufreq_driver->boost_supported;
2404 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2406 int cpufreq_boost_enabled(void)
2408 return cpufreq_driver->boost_enabled;
2410 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2412 /*********************************************************************
2413 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2414 *********************************************************************/
2417 * cpufreq_register_driver - register a CPU Frequency driver
2418 * @driver_data: A struct cpufreq_driver containing the values#
2419 * submitted by the CPU Frequency driver.
2421 * Registers a CPU Frequency driver to this core code. This code
2422 * returns zero on success, -EBUSY when another driver got here first
2423 * (and isn't unregistered in the meantime).
2426 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2428 unsigned long flags;
2431 if (cpufreq_disabled())
2434 if (!driver_data || !driver_data->verify || !driver_data->init ||
2435 !(driver_data->setpolicy || driver_data->target_index ||
2436 driver_data->target) ||
2437 (driver_data->setpolicy && (driver_data->target_index ||
2438 driver_data->target)) ||
2439 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2442 pr_debug("trying to register driver %s\n", driver_data->name);
2444 if (driver_data->setpolicy)
2445 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2447 write_lock_irqsave(&cpufreq_driver_lock, flags);
2448 if (cpufreq_driver) {
2449 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2452 cpufreq_driver = driver_data;
2453 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2455 if (cpufreq_boost_supported()) {
2457 * Check if driver provides function to enable boost -
2458 * if not, use cpufreq_boost_set_sw as default
2460 if (!cpufreq_driver->set_boost)
2461 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2463 ret = cpufreq_sysfs_create_file(&boost.attr);
2465 pr_err("%s: cannot register global BOOST sysfs file\n",
2467 goto err_null_driver;
2471 ret = subsys_interface_register(&cpufreq_interface);
2473 goto err_boost_unreg;
2475 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2479 /* check for at least one working CPU */
2480 for (i = 0; i < nr_cpu_ids; i++)
2481 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2486 /* if all ->init() calls failed, unregister */
2488 pr_debug("no CPU initialized for driver %s\n",
2494 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2495 pr_debug("driver %s up and running\n", driver_data->name);
2499 subsys_interface_unregister(&cpufreq_interface);
2501 if (cpufreq_boost_supported())
2502 cpufreq_sysfs_remove_file(&boost.attr);
2504 write_lock_irqsave(&cpufreq_driver_lock, flags);
2505 cpufreq_driver = NULL;
2506 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2509 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2512 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2514 * Unregister the current CPUFreq driver. Only call this if you have
2515 * the right to do so, i.e. if you have succeeded in initialising before!
2516 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2517 * currently not initialised.
2519 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2521 unsigned long flags;
2523 if (!cpufreq_driver || (driver != cpufreq_driver))
2526 pr_debug("unregistering driver %s\n", driver->name);
2528 subsys_interface_unregister(&cpufreq_interface);
2529 if (cpufreq_boost_supported())
2530 cpufreq_sysfs_remove_file(&boost.attr);
2532 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2534 down_write(&cpufreq_rwsem);
2535 write_lock_irqsave(&cpufreq_driver_lock, flags);
2537 cpufreq_driver = NULL;
2539 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2540 up_write(&cpufreq_rwsem);
2544 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2546 static int __init cpufreq_core_init(void)
2548 if (cpufreq_disabled())
2551 cpufreq_global_kobject = kobject_create();
2552 BUG_ON(!cpufreq_global_kobject);
2556 core_initcall(cpufreq_core_init);