2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10 * Fix handling for CPU hotplug -- affected CPUs
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/notifier.h>
22 #include <linux/cpufreq.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/device.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
31 #include <linux/syscore_ops.h>
33 #include <trace/events/power.h>
36 * The "cpufreq driver" - the arch- or hardware-dependent low
37 * level driver of CPUFreq support, and its spinlock. This lock
38 * also protects the cpufreq_cpu_data array.
40 static struct cpufreq_driver *cpufreq_driver;
41 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
46 static DEFINE_SPINLOCK(cpufreq_driver_lock);
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
52 * The rules for this semaphore:
53 * - Any routine that wants to read from the policy structure will
54 * do a down_read on this semaphore.
55 * - Any routine that will write to the policy structure and/or may take away
56 * the policy altogether (eg. CPU hotplug), will hold this lock in write
57 * mode before doing so.
60 * - All holders of the lock should check to make sure that the CPU they
61 * are concerned with are online after they get the lock.
62 * - Governor routines that can be called in cpufreq hotplug path should not
63 * take this sem as top level hotplug notifier handler takes this.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
67 static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
68 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
70 #define lock_policy_rwsem(mode, cpu) \
71 static int lock_policy_rwsem_##mode \
74 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
75 BUG_ON(policy_cpu == -1); \
76 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
77 if (unlikely(!cpu_online(cpu))) { \
78 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
85 lock_policy_rwsem(read, cpu);
87 lock_policy_rwsem(write, cpu);
89 static void unlock_policy_rwsem_read(int cpu)
91 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
96 static void unlock_policy_rwsem_write(int cpu)
98 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
99 BUG_ON(policy_cpu == -1);
100 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
104 /* internal prototypes */
105 static int __cpufreq_governor(struct cpufreq_policy *policy,
107 static unsigned int __cpufreq_get(unsigned int cpu);
108 static void handle_update(struct work_struct *work);
111 * Two notifier lists: the "policy" list is involved in the
112 * validation process for a new CPU frequency policy; the
113 * "transition" list for kernel code that needs to handle
114 * changes to devices when the CPU clock speed changes.
115 * The mutex locks both lists.
117 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
118 static struct srcu_notifier_head cpufreq_transition_notifier_list;
120 static bool init_cpufreq_transition_notifier_list_called;
121 static int __init init_cpufreq_transition_notifier_list(void)
123 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
124 init_cpufreq_transition_notifier_list_called = true;
127 pure_initcall(init_cpufreq_transition_notifier_list);
129 static int off __read_mostly;
130 int cpufreq_disabled(void)
134 void disable_cpufreq(void)
138 static LIST_HEAD(cpufreq_governor_list);
139 static DEFINE_MUTEX(cpufreq_governor_mutex);
141 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
143 struct cpufreq_policy *data;
146 if (cpu >= nr_cpu_ids)
149 /* get the cpufreq driver */
150 spin_lock_irqsave(&cpufreq_driver_lock, flags);
155 if (!try_module_get(cpufreq_driver->owner))
160 data = per_cpu(cpufreq_cpu_data, cpu);
163 goto err_out_put_module;
165 if (!kobject_get(&data->kobj))
166 goto err_out_put_module;
168 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
172 module_put(cpufreq_driver->owner);
174 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
178 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
181 void cpufreq_cpu_put(struct cpufreq_policy *data)
183 kobject_put(&data->kobj);
184 module_put(cpufreq_driver->owner);
186 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
189 /*********************************************************************
190 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
191 *********************************************************************/
194 * adjust_jiffies - adjust the system "loops_per_jiffy"
196 * This function alters the system "loops_per_jiffy" for the clock
197 * speed change. Note that loops_per_jiffy cannot be updated on SMP
198 * systems as each CPU might be scaled differently. So, use the arch
199 * per-CPU loops_per_jiffy value wherever possible.
202 static unsigned long l_p_j_ref;
203 static unsigned int l_p_j_ref_freq;
205 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
207 if (ci->flags & CPUFREQ_CONST_LOOPS)
210 if (!l_p_j_ref_freq) {
211 l_p_j_ref = loops_per_jiffy;
212 l_p_j_ref_freq = ci->old;
213 pr_debug("saving %lu as reference value for loops_per_jiffy; "
214 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
216 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
217 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
218 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
220 pr_debug("scaling loops_per_jiffy to %lu "
221 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
225 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
233 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
234 * on frequency transition.
236 * This function calls the transition notifiers and the "adjust_jiffies"
237 * function. It is called twice on all CPU frequency changes that have
240 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
242 struct cpufreq_policy *policy;
244 BUG_ON(irqs_disabled());
246 freqs->flags = cpufreq_driver->flags;
247 pr_debug("notification %u of frequency transition to %u kHz\n",
250 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
253 case CPUFREQ_PRECHANGE:
254 /* detect if the driver reported a value as "old frequency"
255 * which is not equal to what the cpufreq core thinks is
258 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
259 if ((policy) && (policy->cpu == freqs->cpu) &&
260 (policy->cur) && (policy->cur != freqs->old)) {
261 pr_debug("Warning: CPU frequency is"
262 " %u, cpufreq assumed %u kHz.\n",
263 freqs->old, policy->cur);
264 freqs->old = policy->cur;
267 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
268 CPUFREQ_PRECHANGE, freqs);
269 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
272 case CPUFREQ_POSTCHANGE:
273 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
274 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
275 (unsigned long)freqs->cpu);
276 trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
277 trace_cpu_frequency(freqs->new, freqs->cpu);
278 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
279 CPUFREQ_POSTCHANGE, freqs);
280 if (likely(policy) && likely(policy->cpu == freqs->cpu))
281 policy->cur = freqs->new;
285 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
289 /*********************************************************************
291 *********************************************************************/
293 static struct cpufreq_governor *__find_governor(const char *str_governor)
295 struct cpufreq_governor *t;
297 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
298 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
305 * cpufreq_parse_governor - parse a governor string
307 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
308 struct cpufreq_governor **governor)
315 if (cpufreq_driver->setpolicy) {
316 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
317 *policy = CPUFREQ_POLICY_PERFORMANCE;
319 } else if (!strnicmp(str_governor, "powersave",
321 *policy = CPUFREQ_POLICY_POWERSAVE;
324 } else if (cpufreq_driver->target) {
325 struct cpufreq_governor *t;
327 mutex_lock(&cpufreq_governor_mutex);
329 t = __find_governor(str_governor);
334 mutex_unlock(&cpufreq_governor_mutex);
335 ret = request_module("cpufreq_%s", str_governor);
336 mutex_lock(&cpufreq_governor_mutex);
339 t = __find_governor(str_governor);
347 mutex_unlock(&cpufreq_governor_mutex);
355 * cpufreq_per_cpu_attr_read() / show_##file_name() -
356 * print out cpufreq information
358 * Write out information from cpufreq_driver->policy[cpu]; object must be
362 #define show_one(file_name, object) \
363 static ssize_t show_##file_name \
364 (struct cpufreq_policy *policy, char *buf) \
366 return sprintf(buf, "%u\n", policy->object); \
369 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
370 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
371 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
372 show_one(scaling_min_freq, min);
373 show_one(scaling_max_freq, max);
374 show_one(scaling_cur_freq, cur);
376 static int __cpufreq_set_policy(struct cpufreq_policy *data,
377 struct cpufreq_policy *policy);
380 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
382 #define store_one(file_name, object) \
383 static ssize_t store_##file_name \
384 (struct cpufreq_policy *policy, const char *buf, size_t count) \
386 unsigned int ret = -EINVAL; \
387 struct cpufreq_policy new_policy; \
389 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
393 ret = sscanf(buf, "%u", &new_policy.object); \
397 ret = __cpufreq_set_policy(policy, &new_policy); \
398 policy->user_policy.object = policy->object; \
400 return ret ? ret : count; \
403 store_one(scaling_min_freq, min);
404 store_one(scaling_max_freq, max);
407 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
409 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
412 unsigned int cur_freq = __cpufreq_get(policy->cpu);
414 return sprintf(buf, "<unknown>");
415 return sprintf(buf, "%u\n", cur_freq);
420 * show_scaling_governor - show the current policy for the specified CPU
422 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
424 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
425 return sprintf(buf, "powersave\n");
426 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
427 return sprintf(buf, "performance\n");
428 else if (policy->governor)
429 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
430 policy->governor->name);
436 * store_scaling_governor - store policy for the specified CPU
438 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
439 const char *buf, size_t count)
441 unsigned int ret = -EINVAL;
442 char str_governor[16];
443 struct cpufreq_policy new_policy;
445 ret = cpufreq_get_policy(&new_policy, policy->cpu);
449 ret = sscanf(buf, "%15s", str_governor);
453 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
454 &new_policy.governor))
457 /* Do not use cpufreq_set_policy here or the user_policy.max
458 will be wrongly overridden */
459 ret = __cpufreq_set_policy(policy, &new_policy);
461 policy->user_policy.policy = policy->policy;
462 policy->user_policy.governor = policy->governor;
471 * show_scaling_driver - show the cpufreq driver currently loaded
473 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
475 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
479 * show_scaling_available_governors - show the available CPUfreq governors
481 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
485 struct cpufreq_governor *t;
487 if (!cpufreq_driver->target) {
488 i += sprintf(buf, "performance powersave");
492 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
493 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
494 - (CPUFREQ_NAME_LEN + 2)))
496 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
499 i += sprintf(&buf[i], "\n");
503 static ssize_t show_cpus(const struct cpumask *mask, char *buf)
508 for_each_cpu(cpu, mask) {
510 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
511 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
512 if (i >= (PAGE_SIZE - 5))
515 i += sprintf(&buf[i], "\n");
520 * show_related_cpus - show the CPUs affected by each transition even if
521 * hw coordination is in use
523 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
525 if (cpumask_empty(policy->related_cpus))
526 return show_cpus(policy->cpus, buf);
527 return show_cpus(policy->related_cpus, buf);
531 * show_affected_cpus - show the CPUs affected by each transition
533 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
535 return show_cpus(policy->cpus, buf);
538 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
539 const char *buf, size_t count)
541 unsigned int freq = 0;
544 if (!policy->governor || !policy->governor->store_setspeed)
547 ret = sscanf(buf, "%u", &freq);
551 policy->governor->store_setspeed(policy, freq);
556 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
558 if (!policy->governor || !policy->governor->show_setspeed)
559 return sprintf(buf, "<unsupported>\n");
561 return policy->governor->show_setspeed(policy, buf);
565 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
567 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
571 if (cpufreq_driver->bios_limit) {
572 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
574 return sprintf(buf, "%u\n", limit);
576 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
579 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
580 cpufreq_freq_attr_ro(cpuinfo_min_freq);
581 cpufreq_freq_attr_ro(cpuinfo_max_freq);
582 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
583 cpufreq_freq_attr_ro(scaling_available_governors);
584 cpufreq_freq_attr_ro(scaling_driver);
585 cpufreq_freq_attr_ro(scaling_cur_freq);
586 cpufreq_freq_attr_ro(bios_limit);
587 cpufreq_freq_attr_ro(related_cpus);
588 cpufreq_freq_attr_ro(affected_cpus);
589 cpufreq_freq_attr_rw(scaling_min_freq);
590 cpufreq_freq_attr_rw(scaling_max_freq);
591 cpufreq_freq_attr_rw(scaling_governor);
592 cpufreq_freq_attr_rw(scaling_setspeed);
594 static struct attribute *default_attrs[] = {
595 &cpuinfo_min_freq.attr,
596 &cpuinfo_max_freq.attr,
597 &cpuinfo_transition_latency.attr,
598 &scaling_min_freq.attr,
599 &scaling_max_freq.attr,
602 &scaling_governor.attr,
603 &scaling_driver.attr,
604 &scaling_available_governors.attr,
605 &scaling_setspeed.attr,
609 struct kobject *cpufreq_global_kobject;
610 EXPORT_SYMBOL(cpufreq_global_kobject);
612 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
613 #define to_attr(a) container_of(a, struct freq_attr, attr)
615 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
617 struct cpufreq_policy *policy = to_policy(kobj);
618 struct freq_attr *fattr = to_attr(attr);
619 ssize_t ret = -EINVAL;
620 policy = cpufreq_cpu_get(policy->cpu);
624 if (lock_policy_rwsem_read(policy->cpu) < 0)
628 ret = fattr->show(policy, buf);
632 unlock_policy_rwsem_read(policy->cpu);
634 cpufreq_cpu_put(policy);
639 static ssize_t store(struct kobject *kobj, struct attribute *attr,
640 const char *buf, size_t count)
642 struct cpufreq_policy *policy = to_policy(kobj);
643 struct freq_attr *fattr = to_attr(attr);
644 ssize_t ret = -EINVAL;
645 policy = cpufreq_cpu_get(policy->cpu);
649 if (lock_policy_rwsem_write(policy->cpu) < 0)
653 ret = fattr->store(policy, buf, count);
657 unlock_policy_rwsem_write(policy->cpu);
659 cpufreq_cpu_put(policy);
664 static void cpufreq_sysfs_release(struct kobject *kobj)
666 struct cpufreq_policy *policy = to_policy(kobj);
667 pr_debug("last reference is dropped\n");
668 complete(&policy->kobj_unregister);
671 static const struct sysfs_ops sysfs_ops = {
676 static struct kobj_type ktype_cpufreq = {
677 .sysfs_ops = &sysfs_ops,
678 .default_attrs = default_attrs,
679 .release = cpufreq_sysfs_release,
686 * Positive: When we have a managed CPU and the sysfs got symlinked
688 static int cpufreq_add_dev_policy(unsigned int cpu,
689 struct cpufreq_policy *policy,
696 #ifdef CONFIG_HOTPLUG_CPU
697 struct cpufreq_governor *gov;
699 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
701 policy->governor = gov;
702 pr_debug("Restoring governor %s for cpu %d\n",
703 policy->governor->name, cpu);
707 for_each_cpu(j, policy->cpus) {
708 struct cpufreq_policy *managed_policy;
713 /* Check for existing affected CPUs.
714 * They may not be aware of it due to CPU Hotplug.
715 * cpufreq_cpu_put is called when the device is removed
716 * in __cpufreq_remove_dev()
718 managed_policy = cpufreq_cpu_get(j);
719 if (unlikely(managed_policy)) {
721 /* Set proper policy_cpu */
722 unlock_policy_rwsem_write(cpu);
723 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
725 if (lock_policy_rwsem_write(cpu) < 0) {
726 /* Should not go through policy unlock path */
727 if (cpufreq_driver->exit)
728 cpufreq_driver->exit(policy);
729 cpufreq_cpu_put(managed_policy);
733 spin_lock_irqsave(&cpufreq_driver_lock, flags);
734 cpumask_copy(managed_policy->cpus, policy->cpus);
735 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
736 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
738 pr_debug("CPU already managed, adding link\n");
739 ret = sysfs_create_link(&dev->kobj,
740 &managed_policy->kobj,
743 cpufreq_cpu_put(managed_policy);
745 * Success. We only needed to be added to the mask.
746 * Call driver->exit() because only the cpu parent of
747 * the kobj needed to call init().
749 if (cpufreq_driver->exit)
750 cpufreq_driver->exit(policy);
763 /* symlink affected CPUs */
764 static int cpufreq_add_dev_symlink(unsigned int cpu,
765 struct cpufreq_policy *policy)
770 for_each_cpu(j, policy->cpus) {
771 struct cpufreq_policy *managed_policy;
772 struct device *cpu_dev;
779 pr_debug("CPU %u already managed, adding link\n", j);
780 managed_policy = cpufreq_cpu_get(cpu);
781 cpu_dev = get_cpu_device(j);
782 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
785 cpufreq_cpu_put(managed_policy);
792 static int cpufreq_add_dev_interface(unsigned int cpu,
793 struct cpufreq_policy *policy,
796 struct cpufreq_policy new_policy;
797 struct freq_attr **drv_attr;
802 /* prepare interface data */
803 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
804 &dev->kobj, "cpufreq");
808 /* set up files for this cpu device */
809 drv_attr = cpufreq_driver->attr;
810 while ((drv_attr) && (*drv_attr)) {
811 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
813 goto err_out_kobj_put;
816 if (cpufreq_driver->get) {
817 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
819 goto err_out_kobj_put;
821 if (cpufreq_driver->target) {
822 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
824 goto err_out_kobj_put;
826 if (cpufreq_driver->bios_limit) {
827 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
829 goto err_out_kobj_put;
832 spin_lock_irqsave(&cpufreq_driver_lock, flags);
833 for_each_cpu(j, policy->cpus) {
836 per_cpu(cpufreq_cpu_data, j) = policy;
837 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
839 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
841 ret = cpufreq_add_dev_symlink(cpu, policy);
843 goto err_out_kobj_put;
845 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
846 /* assure that the starting sequence is run in __cpufreq_set_policy */
847 policy->governor = NULL;
849 /* set default policy */
850 ret = __cpufreq_set_policy(policy, &new_policy);
851 policy->user_policy.policy = policy->policy;
852 policy->user_policy.governor = policy->governor;
855 pr_debug("setting policy failed\n");
856 if (cpufreq_driver->exit)
857 cpufreq_driver->exit(policy);
862 kobject_put(&policy->kobj);
863 wait_for_completion(&policy->kobj_unregister);
869 * cpufreq_add_dev - add a CPU device
871 * Adds the cpufreq interface for a CPU device.
873 * The Oracle says: try running cpufreq registration/unregistration concurrently
874 * with with cpu hotplugging and all hell will break loose. Tried to clean this
875 * mess up, but more thorough testing is needed. - Mathieu
877 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
879 unsigned int cpu = dev->id;
880 int ret = 0, found = 0;
881 struct cpufreq_policy *policy;
884 #ifdef CONFIG_HOTPLUG_CPU
888 if (cpu_is_offline(cpu))
891 pr_debug("adding CPU %u\n", cpu);
894 /* check whether a different CPU already registered this
895 * CPU because it is in the same boat. */
896 policy = cpufreq_cpu_get(cpu);
897 if (unlikely(policy)) {
898 cpufreq_cpu_put(policy);
903 if (!try_module_get(cpufreq_driver->owner)) {
909 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
913 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
914 goto err_free_policy;
916 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
917 goto err_free_cpumask;
920 cpumask_copy(policy->cpus, cpumask_of(cpu));
922 /* Initially set CPU itself as the policy_cpu */
923 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
924 ret = (lock_policy_rwsem_write(cpu) < 0);
927 init_completion(&policy->kobj_unregister);
928 INIT_WORK(&policy->update, handle_update);
930 /* Set governor before ->init, so that driver could check it */
931 #ifdef CONFIG_HOTPLUG_CPU
932 for_each_online_cpu(sibling) {
933 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
934 if (cp && cp->governor &&
935 (cpumask_test_cpu(cpu, cp->related_cpus))) {
936 policy->governor = cp->governor;
943 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
944 /* call driver. From then on the cpufreq must be able
945 * to accept all calls to ->verify and ->setpolicy for this CPU
947 ret = cpufreq_driver->init(policy);
949 pr_debug("initialization failed\n");
950 goto err_unlock_policy;
952 policy->user_policy.min = policy->min;
953 policy->user_policy.max = policy->max;
955 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
956 CPUFREQ_START, policy);
958 ret = cpufreq_add_dev_policy(cpu, policy, dev);
961 /* This is a managed cpu, symlink created,
964 goto err_unlock_policy;
967 ret = cpufreq_add_dev_interface(cpu, policy, dev);
969 goto err_out_unregister;
971 unlock_policy_rwsem_write(cpu);
973 kobject_uevent(&policy->kobj, KOBJ_ADD);
974 module_put(cpufreq_driver->owner);
975 pr_debug("initialization complete\n");
981 spin_lock_irqsave(&cpufreq_driver_lock, flags);
982 for_each_cpu(j, policy->cpus)
983 per_cpu(cpufreq_cpu_data, j) = NULL;
984 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
986 kobject_put(&policy->kobj);
987 wait_for_completion(&policy->kobj_unregister);
990 unlock_policy_rwsem_write(cpu);
991 free_cpumask_var(policy->related_cpus);
993 free_cpumask_var(policy->cpus);
997 module_put(cpufreq_driver->owner);
1004 * __cpufreq_remove_dev - remove a CPU device
1006 * Removes the cpufreq interface for a CPU device.
1007 * Caller should already have policy_rwsem in write mode for this CPU.
1008 * This routine frees the rwsem before returning.
1010 static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1012 unsigned int cpu = dev->id;
1013 unsigned long flags;
1014 struct cpufreq_policy *data;
1015 struct kobject *kobj;
1016 struct completion *cmp;
1018 struct device *cpu_dev;
1022 pr_debug("unregistering CPU %u\n", cpu);
1024 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1025 data = per_cpu(cpufreq_cpu_data, cpu);
1028 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1029 unlock_policy_rwsem_write(cpu);
1032 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1036 /* if this isn't the CPU which is the parent of the kobj, we
1037 * only need to unlink, put and exit
1039 if (unlikely(cpu != data->cpu)) {
1040 pr_debug("removing link\n");
1041 cpumask_clear_cpu(cpu, data->cpus);
1042 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1044 cpufreq_cpu_put(data);
1045 unlock_policy_rwsem_write(cpu);
1046 sysfs_remove_link(kobj, "cpufreq");
1053 #ifdef CONFIG_HOTPLUG_CPU
1054 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1058 /* if we have other CPUs still registered, we need to unlink them,
1059 * or else wait_for_completion below will lock up. Clean the
1060 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1061 * the sysfs links afterwards.
1063 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1064 for_each_cpu(j, data->cpus) {
1067 per_cpu(cpufreq_cpu_data, j) = NULL;
1071 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1073 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1074 for_each_cpu(j, data->cpus) {
1077 pr_debug("removing link for cpu %u\n", j);
1078 #ifdef CONFIG_HOTPLUG_CPU
1079 strncpy(per_cpu(cpufreq_cpu_governor, j),
1080 data->governor->name, CPUFREQ_NAME_LEN);
1082 cpu_dev = get_cpu_device(j);
1083 kobj = &cpu_dev->kobj;
1084 unlock_policy_rwsem_write(cpu);
1085 sysfs_remove_link(kobj, "cpufreq");
1086 lock_policy_rwsem_write(cpu);
1087 cpufreq_cpu_put(data);
1091 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1094 if (cpufreq_driver->target)
1095 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1098 cmp = &data->kobj_unregister;
1099 unlock_policy_rwsem_write(cpu);
1102 /* we need to make sure that the underlying kobj is actually
1103 * not referenced anymore by anybody before we proceed with
1106 pr_debug("waiting for dropping of refcount\n");
1107 wait_for_completion(cmp);
1108 pr_debug("wait complete\n");
1110 lock_policy_rwsem_write(cpu);
1111 if (cpufreq_driver->exit)
1112 cpufreq_driver->exit(data);
1113 unlock_policy_rwsem_write(cpu);
1115 #ifdef CONFIG_HOTPLUG_CPU
1116 /* when the CPU which is the parent of the kobj is hotplugged
1117 * offline, check for siblings, and create cpufreq sysfs interface
1120 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1121 /* first sibling now owns the new sysfs dir */
1122 cpumask_clear_cpu(cpu, data->cpus);
1123 cpufreq_add_dev(get_cpu_device(cpumask_first(data->cpus)), NULL);
1125 /* finally remove our own symlink */
1126 lock_policy_rwsem_write(cpu);
1127 __cpufreq_remove_dev(dev, sif);
1131 free_cpumask_var(data->related_cpus);
1132 free_cpumask_var(data->cpus);
1139 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1141 unsigned int cpu = dev->id;
1144 if (cpu_is_offline(cpu))
1147 if (unlikely(lock_policy_rwsem_write(cpu)))
1150 retval = __cpufreq_remove_dev(dev, sif);
1155 static void handle_update(struct work_struct *work)
1157 struct cpufreq_policy *policy =
1158 container_of(work, struct cpufreq_policy, update);
1159 unsigned int cpu = policy->cpu;
1160 pr_debug("handle_update for cpu %u called\n", cpu);
1161 cpufreq_update_policy(cpu);
1165 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1167 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1168 * @new_freq: CPU frequency the CPU actually runs at
1170 * We adjust to current frequency first, and need to clean up later.
1171 * So either call to cpufreq_update_policy() or schedule handle_update()).
1173 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1174 unsigned int new_freq)
1176 struct cpufreq_freqs freqs;
1178 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1179 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1182 freqs.old = old_freq;
1183 freqs.new = new_freq;
1184 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1185 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1190 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1193 * This is the last known freq, without actually getting it from the driver.
1194 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1196 unsigned int cpufreq_quick_get(unsigned int cpu)
1198 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1199 unsigned int ret_freq = 0;
1202 ret_freq = policy->cur;
1203 cpufreq_cpu_put(policy);
1208 EXPORT_SYMBOL(cpufreq_quick_get);
1211 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1214 * Just return the max possible frequency for a given CPU.
1216 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1218 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1219 unsigned int ret_freq = 0;
1222 ret_freq = policy->max;
1223 cpufreq_cpu_put(policy);
1228 EXPORT_SYMBOL(cpufreq_quick_get_max);
1231 static unsigned int __cpufreq_get(unsigned int cpu)
1233 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1234 unsigned int ret_freq = 0;
1236 if (!cpufreq_driver->get)
1239 ret_freq = cpufreq_driver->get(cpu);
1241 if (ret_freq && policy->cur &&
1242 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1243 /* verify no discrepancy between actual and
1244 saved value exists */
1245 if (unlikely(ret_freq != policy->cur)) {
1246 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1247 schedule_work(&policy->update);
1255 * cpufreq_get - get the current CPU frequency (in kHz)
1258 * Get the CPU current (static) CPU frequency
1260 unsigned int cpufreq_get(unsigned int cpu)
1262 unsigned int ret_freq = 0;
1263 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1268 if (unlikely(lock_policy_rwsem_read(cpu)))
1271 ret_freq = __cpufreq_get(cpu);
1273 unlock_policy_rwsem_read(cpu);
1276 cpufreq_cpu_put(policy);
1280 EXPORT_SYMBOL(cpufreq_get);
1282 static struct subsys_interface cpufreq_interface = {
1284 .subsys = &cpu_subsys,
1285 .add_dev = cpufreq_add_dev,
1286 .remove_dev = cpufreq_remove_dev,
1291 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1293 * This function is only executed for the boot processor. The other CPUs
1294 * have been put offline by means of CPU hotplug.
1296 static int cpufreq_bp_suspend(void)
1300 int cpu = smp_processor_id();
1301 struct cpufreq_policy *cpu_policy;
1303 pr_debug("suspending cpu %u\n", cpu);
1305 /* If there's no policy for the boot CPU, we have nothing to do. */
1306 cpu_policy = cpufreq_cpu_get(cpu);
1310 if (cpufreq_driver->suspend) {
1311 ret = cpufreq_driver->suspend(cpu_policy);
1313 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1314 "step on CPU %u\n", cpu_policy->cpu);
1317 cpufreq_cpu_put(cpu_policy);
1322 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1324 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1325 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1326 * restored. It will verify that the current freq is in sync with
1327 * what we believe it to be. This is a bit later than when it
1328 * should be, but nonethteless it's better than calling
1329 * cpufreq_driver->get() here which might re-enable interrupts...
1331 * This function is only executed for the boot CPU. The other CPUs have not
1332 * been turned on yet.
1334 static void cpufreq_bp_resume(void)
1338 int cpu = smp_processor_id();
1339 struct cpufreq_policy *cpu_policy;
1341 pr_debug("resuming cpu %u\n", cpu);
1343 /* If there's no policy for the boot CPU, we have nothing to do. */
1344 cpu_policy = cpufreq_cpu_get(cpu);
1348 if (cpufreq_driver->resume) {
1349 ret = cpufreq_driver->resume(cpu_policy);
1351 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1352 "step on CPU %u\n", cpu_policy->cpu);
1357 schedule_work(&cpu_policy->update);
1360 cpufreq_cpu_put(cpu_policy);
1363 static struct syscore_ops cpufreq_syscore_ops = {
1364 .suspend = cpufreq_bp_suspend,
1365 .resume = cpufreq_bp_resume,
1369 /*********************************************************************
1370 * NOTIFIER LISTS INTERFACE *
1371 *********************************************************************/
1374 * cpufreq_register_notifier - register a driver with cpufreq
1375 * @nb: notifier function to register
1376 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1378 * Add a driver to one of two lists: either a list of drivers that
1379 * are notified about clock rate changes (once before and once after
1380 * the transition), or a list of drivers that are notified about
1381 * changes in cpufreq policy.
1383 * This function may sleep, and has the same return conditions as
1384 * blocking_notifier_chain_register.
1386 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1390 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1393 case CPUFREQ_TRANSITION_NOTIFIER:
1394 ret = srcu_notifier_chain_register(
1395 &cpufreq_transition_notifier_list, nb);
1397 case CPUFREQ_POLICY_NOTIFIER:
1398 ret = blocking_notifier_chain_register(
1399 &cpufreq_policy_notifier_list, nb);
1407 EXPORT_SYMBOL(cpufreq_register_notifier);
1411 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1412 * @nb: notifier block to be unregistered
1413 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1415 * Remove a driver from the CPU frequency notifier list.
1417 * This function may sleep, and has the same return conditions as
1418 * blocking_notifier_chain_unregister.
1420 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1425 case CPUFREQ_TRANSITION_NOTIFIER:
1426 ret = srcu_notifier_chain_unregister(
1427 &cpufreq_transition_notifier_list, nb);
1429 case CPUFREQ_POLICY_NOTIFIER:
1430 ret = blocking_notifier_chain_unregister(
1431 &cpufreq_policy_notifier_list, nb);
1439 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1442 /*********************************************************************
1444 *********************************************************************/
1447 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1448 unsigned int target_freq,
1449 unsigned int relation)
1451 int retval = -EINVAL;
1453 if (cpufreq_disabled())
1456 pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1457 target_freq, relation);
1458 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1459 retval = cpufreq_driver->target(policy, target_freq, relation);
1463 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1465 int cpufreq_driver_target(struct cpufreq_policy *policy,
1466 unsigned int target_freq,
1467 unsigned int relation)
1471 policy = cpufreq_cpu_get(policy->cpu);
1475 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1478 ret = __cpufreq_driver_target(policy, target_freq, relation);
1480 unlock_policy_rwsem_write(policy->cpu);
1483 cpufreq_cpu_put(policy);
1487 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1489 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1493 policy = cpufreq_cpu_get(policy->cpu);
1497 if (cpu_online(cpu) && cpufreq_driver->getavg)
1498 ret = cpufreq_driver->getavg(policy, cpu);
1500 cpufreq_cpu_put(policy);
1503 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1506 * when "event" is CPUFREQ_GOV_LIMITS
1509 static int __cpufreq_governor(struct cpufreq_policy *policy,
1514 /* Only must be defined when default governor is known to have latency
1515 restrictions, like e.g. conservative or ondemand.
1516 That this is the case is already ensured in Kconfig
1518 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1519 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1521 struct cpufreq_governor *gov = NULL;
1524 if (policy->governor->max_transition_latency &&
1525 policy->cpuinfo.transition_latency >
1526 policy->governor->max_transition_latency) {
1530 printk(KERN_WARNING "%s governor failed, too long"
1531 " transition latency of HW, fallback"
1532 " to %s governor\n",
1533 policy->governor->name,
1535 policy->governor = gov;
1539 if (!try_module_get(policy->governor->owner))
1542 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1543 policy->cpu, event);
1544 ret = policy->governor->governor(policy, event);
1546 /* we keep one module reference alive for
1547 each CPU governed by this CPU */
1548 if ((event != CPUFREQ_GOV_START) || ret)
1549 module_put(policy->governor->owner);
1550 if ((event == CPUFREQ_GOV_STOP) && !ret)
1551 module_put(policy->governor->owner);
1557 int cpufreq_register_governor(struct cpufreq_governor *governor)
1564 if (cpufreq_disabled())
1567 mutex_lock(&cpufreq_governor_mutex);
1570 if (__find_governor(governor->name) == NULL) {
1572 list_add(&governor->governor_list, &cpufreq_governor_list);
1575 mutex_unlock(&cpufreq_governor_mutex);
1578 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1581 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1583 #ifdef CONFIG_HOTPLUG_CPU
1590 if (cpufreq_disabled())
1593 #ifdef CONFIG_HOTPLUG_CPU
1594 for_each_present_cpu(cpu) {
1595 if (cpu_online(cpu))
1597 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1598 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1602 mutex_lock(&cpufreq_governor_mutex);
1603 list_del(&governor->governor_list);
1604 mutex_unlock(&cpufreq_governor_mutex);
1607 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1611 /*********************************************************************
1612 * POLICY INTERFACE *
1613 *********************************************************************/
1616 * cpufreq_get_policy - get the current cpufreq_policy
1617 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1620 * Reads the current cpufreq policy.
1622 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1624 struct cpufreq_policy *cpu_policy;
1628 cpu_policy = cpufreq_cpu_get(cpu);
1632 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1634 cpufreq_cpu_put(cpu_policy);
1637 EXPORT_SYMBOL(cpufreq_get_policy);
1641 * data : current policy.
1642 * policy : policy to be set.
1644 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1645 struct cpufreq_policy *policy)
1649 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1650 policy->min, policy->max);
1652 memcpy(&policy->cpuinfo, &data->cpuinfo,
1653 sizeof(struct cpufreq_cpuinfo));
1655 if (policy->min > data->max || policy->max < data->min) {
1660 /* verify the cpu speed can be set within this limit */
1661 ret = cpufreq_driver->verify(policy);
1665 /* adjust if necessary - all reasons */
1666 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1667 CPUFREQ_ADJUST, policy);
1669 /* adjust if necessary - hardware incompatibility*/
1670 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1671 CPUFREQ_INCOMPATIBLE, policy);
1673 /* verify the cpu speed can be set within this limit,
1674 which might be different to the first one */
1675 ret = cpufreq_driver->verify(policy);
1679 /* notification of the new policy */
1680 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1681 CPUFREQ_NOTIFY, policy);
1683 data->min = policy->min;
1684 data->max = policy->max;
1686 pr_debug("new min and max freqs are %u - %u kHz\n",
1687 data->min, data->max);
1689 if (cpufreq_driver->setpolicy) {
1690 data->policy = policy->policy;
1691 pr_debug("setting range\n");
1692 ret = cpufreq_driver->setpolicy(policy);
1694 if (policy->governor != data->governor) {
1695 /* save old, working values */
1696 struct cpufreq_governor *old_gov = data->governor;
1698 pr_debug("governor switch\n");
1700 /* end old governor */
1702 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1704 /* start new governor */
1705 data->governor = policy->governor;
1706 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1707 /* new governor failed, so re-start old one */
1708 pr_debug("starting governor %s failed\n",
1709 data->governor->name);
1711 data->governor = old_gov;
1712 __cpufreq_governor(data,
1718 /* might be a policy change, too, so fall through */
1720 pr_debug("governor: change or update limits\n");
1721 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1729 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1730 * @cpu: CPU which shall be re-evaluated
1732 * Useful for policy notifiers which have different necessities
1733 * at different times.
1735 int cpufreq_update_policy(unsigned int cpu)
1737 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1738 struct cpufreq_policy policy;
1746 if (unlikely(lock_policy_rwsem_write(cpu))) {
1751 pr_debug("updating policy for CPU %u\n", cpu);
1752 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1753 policy.min = data->user_policy.min;
1754 policy.max = data->user_policy.max;
1755 policy.policy = data->user_policy.policy;
1756 policy.governor = data->user_policy.governor;
1758 /* BIOS might change freq behind our back
1759 -> ask driver for current freq and notify governors about a change */
1760 if (cpufreq_driver->get) {
1761 policy.cur = cpufreq_driver->get(cpu);
1763 pr_debug("Driver did not initialize current freq");
1764 data->cur = policy.cur;
1766 if (data->cur != policy.cur)
1767 cpufreq_out_of_sync(cpu, data->cur,
1772 ret = __cpufreq_set_policy(data, &policy);
1774 unlock_policy_rwsem_write(cpu);
1777 cpufreq_cpu_put(data);
1781 EXPORT_SYMBOL(cpufreq_update_policy);
1783 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1784 unsigned long action, void *hcpu)
1786 unsigned int cpu = (unsigned long)hcpu;
1789 dev = get_cpu_device(cpu);
1793 case CPU_ONLINE_FROZEN:
1794 cpufreq_add_dev(dev, NULL);
1796 case CPU_DOWN_PREPARE:
1797 case CPU_DOWN_PREPARE_FROZEN:
1798 if (unlikely(lock_policy_rwsem_write(cpu)))
1801 __cpufreq_remove_dev(dev, NULL);
1803 case CPU_DOWN_FAILED:
1804 case CPU_DOWN_FAILED_FROZEN:
1805 cpufreq_add_dev(dev, NULL);
1812 static struct notifier_block __refdata cpufreq_cpu_notifier = {
1813 .notifier_call = cpufreq_cpu_callback,
1816 /*********************************************************************
1817 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1818 *********************************************************************/
1821 * cpufreq_register_driver - register a CPU Frequency driver
1822 * @driver_data: A struct cpufreq_driver containing the values#
1823 * submitted by the CPU Frequency driver.
1825 * Registers a CPU Frequency driver to this core code. This code
1826 * returns zero on success, -EBUSY when another driver got here first
1827 * (and isn't unregistered in the meantime).
1830 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1832 unsigned long flags;
1835 if (cpufreq_disabled())
1838 if (!driver_data || !driver_data->verify || !driver_data->init ||
1839 ((!driver_data->setpolicy) && (!driver_data->target)))
1842 pr_debug("trying to register driver %s\n", driver_data->name);
1844 if (driver_data->setpolicy)
1845 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1847 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1848 if (cpufreq_driver) {
1849 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1852 cpufreq_driver = driver_data;
1853 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1855 ret = subsys_interface_register(&cpufreq_interface);
1857 goto err_null_driver;
1859 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1863 /* check for at least one working CPU */
1864 for (i = 0; i < nr_cpu_ids; i++)
1865 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1870 /* if all ->init() calls failed, unregister */
1872 pr_debug("no CPU initialized for driver %s\n",
1878 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1879 pr_debug("driver %s up and running\n", driver_data->name);
1883 subsys_interface_unregister(&cpufreq_interface);
1885 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1886 cpufreq_driver = NULL;
1887 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1890 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1894 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1896 * Unregister the current CPUFreq driver. Only call this if you have
1897 * the right to do so, i.e. if you have succeeded in initialising before!
1898 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1899 * currently not initialised.
1901 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1903 unsigned long flags;
1905 if (!cpufreq_driver || (driver != cpufreq_driver))
1908 pr_debug("unregistering driver %s\n", driver->name);
1910 subsys_interface_unregister(&cpufreq_interface);
1911 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1913 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1914 cpufreq_driver = NULL;
1915 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1919 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1921 static int __init cpufreq_core_init(void)
1925 if (cpufreq_disabled())
1928 for_each_possible_cpu(cpu) {
1929 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1930 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1933 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
1934 BUG_ON(!cpufreq_global_kobject);
1935 register_syscore_ops(&cpufreq_syscore_ops);
1939 core_initcall(cpufreq_core_init);