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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/notifier.h>
24 #include <linux/cpufreq.h>
25 #include <linux/delay.h>
26 #include <linux/interrupt.h>
27 #include <linux/spinlock.h>
28 #include <linux/device.h>
29 #include <linux/slab.h>
30 #include <linux/cpu.h>
31 #include <linux/completion.h>
32 #include <linux/mutex.h>
33 #include <linux/syscore_ops.h>
35 #include <trace/events/power.h>
38 * The "cpufreq driver" - the arch- or hardware-dependent low
39 * level driver of CPUFreq support, and its spinlock. This lock
40 * also protects the cpufreq_cpu_data array.
42 static struct cpufreq_driver *cpufreq_driver;
43 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
44 #ifdef CONFIG_HOTPLUG_CPU
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 static DEFINE_RWLOCK(cpufreq_driver_lock);
51 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
52 * all cpufreq/hotplug/workqueue/etc related lock issues.
54 * The rules for this semaphore:
55 * - Any routine that wants to read from the policy structure will
56 * do a down_read on this semaphore.
57 * - Any routine that will write to the policy structure and/or may take away
58 * the policy altogether (eg. CPU hotplug), will hold this lock in write
59 * mode before doing so.
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(int cpu) \
73 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
74 BUG_ON(policy_cpu == -1); \
75 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
80 lock_policy_rwsem(read, cpu);
81 lock_policy_rwsem(write, cpu);
83 #define unlock_policy_rwsem(mode, cpu) \
84 static void unlock_policy_rwsem_##mode(int cpu) \
86 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
87 BUG_ON(policy_cpu == -1); \
88 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
91 unlock_policy_rwsem(read, cpu);
92 unlock_policy_rwsem(write, cpu);
94 /* internal prototypes */
95 static int __cpufreq_governor(struct cpufreq_policy *policy,
97 static unsigned int __cpufreq_get(unsigned int cpu);
98 static void handle_update(struct work_struct *work);
101 * Two notifier lists: the "policy" list is involved in the
102 * validation process for a new CPU frequency policy; the
103 * "transition" list for kernel code that needs to handle
104 * changes to devices when the CPU clock speed changes.
105 * The mutex locks both lists.
107 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
108 static struct srcu_notifier_head cpufreq_transition_notifier_list;
110 static bool init_cpufreq_transition_notifier_list_called;
111 static int __init init_cpufreq_transition_notifier_list(void)
113 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
114 init_cpufreq_transition_notifier_list_called = true;
117 pure_initcall(init_cpufreq_transition_notifier_list);
119 static int off __read_mostly;
120 static int cpufreq_disabled(void)
124 void disable_cpufreq(void)
128 static LIST_HEAD(cpufreq_governor_list);
129 static DEFINE_MUTEX(cpufreq_governor_mutex);
131 bool have_governor_per_policy(void)
133 return cpufreq_driver->have_governor_per_policy;
135 EXPORT_SYMBOL_GPL(have_governor_per_policy);
137 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
139 if (have_governor_per_policy())
140 return &policy->kobj;
142 return cpufreq_global_kobject;
144 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
146 static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
148 struct cpufreq_policy *data;
151 if (cpu >= nr_cpu_ids)
154 /* get the cpufreq driver */
155 read_lock_irqsave(&cpufreq_driver_lock, flags);
160 if (!try_module_get(cpufreq_driver->owner))
165 data = per_cpu(cpufreq_cpu_data, cpu);
168 goto err_out_put_module;
170 if (!sysfs && !kobject_get(&data->kobj))
171 goto err_out_put_module;
173 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
177 module_put(cpufreq_driver->owner);
179 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
184 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
186 if (cpufreq_disabled())
189 return __cpufreq_cpu_get(cpu, false);
191 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
193 static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu)
195 return __cpufreq_cpu_get(cpu, true);
198 static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs)
201 kobject_put(&data->kobj);
202 module_put(cpufreq_driver->owner);
205 void cpufreq_cpu_put(struct cpufreq_policy *data)
207 if (cpufreq_disabled())
210 __cpufreq_cpu_put(data, false);
212 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
214 static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data)
216 __cpufreq_cpu_put(data, true);
219 /*********************************************************************
220 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
221 *********************************************************************/
224 * adjust_jiffies - adjust the system "loops_per_jiffy"
226 * This function alters the system "loops_per_jiffy" for the clock
227 * speed change. Note that loops_per_jiffy cannot be updated on SMP
228 * systems as each CPU might be scaled differently. So, use the arch
229 * per-CPU loops_per_jiffy value wherever possible.
232 static unsigned long l_p_j_ref;
233 static unsigned int l_p_j_ref_freq;
235 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
237 if (ci->flags & CPUFREQ_CONST_LOOPS)
240 if (!l_p_j_ref_freq) {
241 l_p_j_ref = loops_per_jiffy;
242 l_p_j_ref_freq = ci->old;
243 pr_debug("saving %lu as reference value for loops_per_jiffy; "
244 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
246 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
247 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
248 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
250 pr_debug("scaling loops_per_jiffy to %lu "
251 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
255 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
262 void __cpufreq_notify_transition(struct cpufreq_policy *policy,
263 struct cpufreq_freqs *freqs, unsigned int state)
265 BUG_ON(irqs_disabled());
267 if (cpufreq_disabled())
270 freqs->flags = cpufreq_driver->flags;
271 pr_debug("notification %u of frequency transition to %u kHz\n",
276 case CPUFREQ_PRECHANGE:
277 /* detect if the driver reported a value as "old frequency"
278 * which is not equal to what the cpufreq core thinks is
281 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
282 if ((policy) && (policy->cpu == freqs->cpu) &&
283 (policy->cur) && (policy->cur != freqs->old)) {
284 pr_debug("Warning: CPU frequency is"
285 " %u, cpufreq assumed %u kHz.\n",
286 freqs->old, policy->cur);
287 freqs->old = policy->cur;
290 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
291 CPUFREQ_PRECHANGE, freqs);
292 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
295 case CPUFREQ_POSTCHANGE:
296 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
297 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
298 (unsigned long)freqs->cpu);
299 trace_cpu_frequency(freqs->new, freqs->cpu);
300 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
301 CPUFREQ_POSTCHANGE, freqs);
302 if (likely(policy) && likely(policy->cpu == freqs->cpu))
303 policy->cur = freqs->new;
308 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
309 * on frequency transition.
311 * This function calls the transition notifiers and the "adjust_jiffies"
312 * function. It is called twice on all CPU frequency changes that have
315 void cpufreq_notify_transition(struct cpufreq_policy *policy,
316 struct cpufreq_freqs *freqs, unsigned int state)
318 for_each_cpu(freqs->cpu, policy->cpus)
319 __cpufreq_notify_transition(policy, freqs, state);
321 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
325 /*********************************************************************
327 *********************************************************************/
329 static struct cpufreq_governor *__find_governor(const char *str_governor)
331 struct cpufreq_governor *t;
333 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
334 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
341 * cpufreq_parse_governor - parse a governor string
343 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
344 struct cpufreq_governor **governor)
351 if (cpufreq_driver->setpolicy) {
352 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
353 *policy = CPUFREQ_POLICY_PERFORMANCE;
355 } else if (!strnicmp(str_governor, "powersave",
357 *policy = CPUFREQ_POLICY_POWERSAVE;
360 } else if (cpufreq_driver->target) {
361 struct cpufreq_governor *t;
363 mutex_lock(&cpufreq_governor_mutex);
365 t = __find_governor(str_governor);
370 mutex_unlock(&cpufreq_governor_mutex);
371 ret = request_module("cpufreq_%s", str_governor);
372 mutex_lock(&cpufreq_governor_mutex);
375 t = __find_governor(str_governor);
383 mutex_unlock(&cpufreq_governor_mutex);
391 * cpufreq_per_cpu_attr_read() / show_##file_name() -
392 * print out cpufreq information
394 * Write out information from cpufreq_driver->policy[cpu]; object must be
398 #define show_one(file_name, object) \
399 static ssize_t show_##file_name \
400 (struct cpufreq_policy *policy, char *buf) \
402 return sprintf(buf, "%u\n", policy->object); \
405 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
406 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
407 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
408 show_one(scaling_min_freq, min);
409 show_one(scaling_max_freq, max);
410 show_one(scaling_cur_freq, cur);
412 static int __cpufreq_set_policy(struct cpufreq_policy *data,
413 struct cpufreq_policy *policy);
416 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
418 #define store_one(file_name, object) \
419 static ssize_t store_##file_name \
420 (struct cpufreq_policy *policy, const char *buf, size_t count) \
423 struct cpufreq_policy new_policy; \
425 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
429 ret = sscanf(buf, "%u", &new_policy.object); \
433 ret = __cpufreq_set_policy(policy, &new_policy); \
434 policy->user_policy.object = policy->object; \
436 return ret ? ret : count; \
439 store_one(scaling_min_freq, min);
440 store_one(scaling_max_freq, max);
443 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
445 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
448 unsigned int cur_freq = __cpufreq_get(policy->cpu);
450 return sprintf(buf, "<unknown>");
451 return sprintf(buf, "%u\n", cur_freq);
456 * show_scaling_governor - show the current policy for the specified CPU
458 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
460 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
461 return sprintf(buf, "powersave\n");
462 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
463 return sprintf(buf, "performance\n");
464 else if (policy->governor)
465 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
466 policy->governor->name);
472 * store_scaling_governor - store policy for the specified CPU
474 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
475 const char *buf, size_t count)
478 char str_governor[16];
479 struct cpufreq_policy new_policy;
481 ret = cpufreq_get_policy(&new_policy, policy->cpu);
485 ret = sscanf(buf, "%15s", str_governor);
489 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
490 &new_policy.governor))
493 /* Do not use cpufreq_set_policy here or the user_policy.max
494 will be wrongly overridden */
495 ret = __cpufreq_set_policy(policy, &new_policy);
497 policy->user_policy.policy = policy->policy;
498 policy->user_policy.governor = policy->governor;
507 * show_scaling_driver - show the cpufreq driver currently loaded
509 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
511 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
515 * show_scaling_available_governors - show the available CPUfreq governors
517 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
521 struct cpufreq_governor *t;
523 if (!cpufreq_driver->target) {
524 i += sprintf(buf, "performance powersave");
528 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
529 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
530 - (CPUFREQ_NAME_LEN + 2)))
532 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
535 i += sprintf(&buf[i], "\n");
539 static ssize_t show_cpus(const struct cpumask *mask, char *buf)
544 for_each_cpu(cpu, mask) {
546 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
547 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
548 if (i >= (PAGE_SIZE - 5))
551 i += sprintf(&buf[i], "\n");
556 * show_related_cpus - show the CPUs affected by each transition even if
557 * hw coordination is in use
559 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
561 return show_cpus(policy->related_cpus, buf);
565 * show_affected_cpus - show the CPUs affected by each transition
567 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
569 return show_cpus(policy->cpus, buf);
572 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
573 const char *buf, size_t count)
575 unsigned int freq = 0;
578 if (!policy->governor || !policy->governor->store_setspeed)
581 ret = sscanf(buf, "%u", &freq);
585 policy->governor->store_setspeed(policy, freq);
590 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
592 if (!policy->governor || !policy->governor->show_setspeed)
593 return sprintf(buf, "<unsupported>\n");
595 return policy->governor->show_setspeed(policy, buf);
599 * show_bios_limit - show the current cpufreq HW/BIOS limitation
601 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
605 if (cpufreq_driver->bios_limit) {
606 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
608 return sprintf(buf, "%u\n", limit);
610 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
613 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
614 cpufreq_freq_attr_ro(cpuinfo_min_freq);
615 cpufreq_freq_attr_ro(cpuinfo_max_freq);
616 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
617 cpufreq_freq_attr_ro(scaling_available_governors);
618 cpufreq_freq_attr_ro(scaling_driver);
619 cpufreq_freq_attr_ro(scaling_cur_freq);
620 cpufreq_freq_attr_ro(bios_limit);
621 cpufreq_freq_attr_ro(related_cpus);
622 cpufreq_freq_attr_ro(affected_cpus);
623 cpufreq_freq_attr_rw(scaling_min_freq);
624 cpufreq_freq_attr_rw(scaling_max_freq);
625 cpufreq_freq_attr_rw(scaling_governor);
626 cpufreq_freq_attr_rw(scaling_setspeed);
628 static struct attribute *default_attrs[] = {
629 &cpuinfo_min_freq.attr,
630 &cpuinfo_max_freq.attr,
631 &cpuinfo_transition_latency.attr,
632 &scaling_min_freq.attr,
633 &scaling_max_freq.attr,
636 &scaling_governor.attr,
637 &scaling_driver.attr,
638 &scaling_available_governors.attr,
639 &scaling_setspeed.attr,
643 struct kobject *cpufreq_global_kobject;
644 EXPORT_SYMBOL(cpufreq_global_kobject);
646 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
647 #define to_attr(a) container_of(a, struct freq_attr, attr)
649 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
651 struct cpufreq_policy *policy = to_policy(kobj);
652 struct freq_attr *fattr = to_attr(attr);
653 ssize_t ret = -EINVAL;
654 policy = cpufreq_cpu_get_sysfs(policy->cpu);
658 if (lock_policy_rwsem_read(policy->cpu) < 0)
662 ret = fattr->show(policy, buf);
666 unlock_policy_rwsem_read(policy->cpu);
668 cpufreq_cpu_put_sysfs(policy);
673 static ssize_t store(struct kobject *kobj, struct attribute *attr,
674 const char *buf, size_t count)
676 struct cpufreq_policy *policy = to_policy(kobj);
677 struct freq_attr *fattr = to_attr(attr);
678 ssize_t ret = -EINVAL;
679 policy = cpufreq_cpu_get_sysfs(policy->cpu);
683 if (lock_policy_rwsem_write(policy->cpu) < 0)
687 ret = fattr->store(policy, buf, count);
691 unlock_policy_rwsem_write(policy->cpu);
693 cpufreq_cpu_put_sysfs(policy);
698 static void cpufreq_sysfs_release(struct kobject *kobj)
700 struct cpufreq_policy *policy = to_policy(kobj);
701 pr_debug("last reference is dropped\n");
702 complete(&policy->kobj_unregister);
705 static const struct sysfs_ops sysfs_ops = {
710 static struct kobj_type ktype_cpufreq = {
711 .sysfs_ops = &sysfs_ops,
712 .default_attrs = default_attrs,
713 .release = cpufreq_sysfs_release,
716 /* symlink affected CPUs */
717 static int cpufreq_add_dev_symlink(unsigned int cpu,
718 struct cpufreq_policy *policy)
723 for_each_cpu(j, policy->cpus) {
724 struct cpufreq_policy *managed_policy;
725 struct device *cpu_dev;
730 pr_debug("CPU %u already managed, adding link\n", j);
731 managed_policy = cpufreq_cpu_get(cpu);
732 cpu_dev = get_cpu_device(j);
733 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
736 cpufreq_cpu_put(managed_policy);
743 static int cpufreq_add_dev_interface(unsigned int cpu,
744 struct cpufreq_policy *policy,
747 struct cpufreq_policy new_policy;
748 struct freq_attr **drv_attr;
753 /* prepare interface data */
754 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
755 &dev->kobj, "cpufreq");
759 /* set up files for this cpu device */
760 drv_attr = cpufreq_driver->attr;
761 while ((drv_attr) && (*drv_attr)) {
762 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
764 goto err_out_kobj_put;
767 if (cpufreq_driver->get) {
768 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
770 goto err_out_kobj_put;
772 if (cpufreq_driver->target) {
773 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
775 goto err_out_kobj_put;
777 if (cpufreq_driver->bios_limit) {
778 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
780 goto err_out_kobj_put;
783 write_lock_irqsave(&cpufreq_driver_lock, flags);
784 for_each_cpu(j, policy->cpus) {
785 per_cpu(cpufreq_cpu_data, j) = policy;
786 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
788 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
790 ret = cpufreq_add_dev_symlink(cpu, policy);
792 goto err_out_kobj_put;
794 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
795 /* assure that the starting sequence is run in __cpufreq_set_policy */
796 policy->governor = NULL;
798 /* set default policy */
799 ret = __cpufreq_set_policy(policy, &new_policy);
800 policy->user_policy.policy = policy->policy;
801 policy->user_policy.governor = policy->governor;
804 pr_debug("setting policy failed\n");
805 if (cpufreq_driver->exit)
806 cpufreq_driver->exit(policy);
811 kobject_put(&policy->kobj);
812 wait_for_completion(&policy->kobj_unregister);
816 #ifdef CONFIG_HOTPLUG_CPU
817 static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
820 struct cpufreq_policy *policy;
821 int ret = 0, has_target = !!cpufreq_driver->target;
824 policy = cpufreq_cpu_get(sibling);
828 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
830 lock_policy_rwsem_write(sibling);
832 write_lock_irqsave(&cpufreq_driver_lock, flags);
834 cpumask_set_cpu(cpu, policy->cpus);
835 per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu;
836 per_cpu(cpufreq_cpu_data, cpu) = policy;
837 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
839 unlock_policy_rwsem_write(sibling);
842 __cpufreq_governor(policy, CPUFREQ_GOV_START);
843 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
846 ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
848 cpufreq_cpu_put(policy);
857 * cpufreq_add_dev - add a CPU device
859 * Adds the cpufreq interface for a CPU device.
861 * The Oracle says: try running cpufreq registration/unregistration concurrently
862 * with with cpu hotplugging and all hell will break loose. Tried to clean this
863 * mess up, but more thorough testing is needed. - Mathieu
865 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
867 unsigned int j, cpu = dev->id;
869 struct cpufreq_policy *policy;
871 #ifdef CONFIG_HOTPLUG_CPU
872 struct cpufreq_governor *gov;
876 if (cpu_is_offline(cpu))
879 pr_debug("adding CPU %u\n", cpu);
882 /* check whether a different CPU already registered this
883 * CPU because it is in the same boat. */
884 policy = cpufreq_cpu_get(cpu);
885 if (unlikely(policy)) {
886 cpufreq_cpu_put(policy);
890 #ifdef CONFIG_HOTPLUG_CPU
891 /* Check if this cpu was hot-unplugged earlier and has siblings */
892 read_lock_irqsave(&cpufreq_driver_lock, flags);
893 for_each_online_cpu(sibling) {
894 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
895 if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) {
896 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
897 return cpufreq_add_policy_cpu(cpu, sibling, dev);
900 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
904 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 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
921 cpumask_copy(policy->cpus, cpumask_of(cpu));
923 /* Initially set CPU itself as the policy_cpu */
924 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
926 init_completion(&policy->kobj_unregister);
927 INIT_WORK(&policy->update, handle_update);
929 /* call driver. From then on the cpufreq must be able
930 * to accept all calls to ->verify and ->setpolicy for this CPU
932 ret = cpufreq_driver->init(policy);
934 pr_debug("initialization failed\n");
935 goto err_set_policy_cpu;
938 /* related cpus should atleast have policy->cpus */
939 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
942 * affected cpus must always be the one, which are online. We aren't
943 * managing offline cpus here.
945 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
947 policy->user_policy.min = policy->min;
948 policy->user_policy.max = policy->max;
950 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
951 CPUFREQ_START, policy);
953 #ifdef CONFIG_HOTPLUG_CPU
954 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
956 policy->governor = gov;
957 pr_debug("Restoring governor %s for cpu %d\n",
958 policy->governor->name, cpu);
962 ret = cpufreq_add_dev_interface(cpu, policy, dev);
964 goto err_out_unregister;
966 kobject_uevent(&policy->kobj, KOBJ_ADD);
967 module_put(cpufreq_driver->owner);
968 pr_debug("initialization complete\n");
973 write_lock_irqsave(&cpufreq_driver_lock, flags);
974 for_each_cpu(j, policy->cpus)
975 per_cpu(cpufreq_cpu_data, j) = NULL;
976 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
978 kobject_put(&policy->kobj);
979 wait_for_completion(&policy->kobj_unregister);
982 per_cpu(cpufreq_policy_cpu, cpu) = -1;
983 free_cpumask_var(policy->related_cpus);
985 free_cpumask_var(policy->cpus);
989 module_put(cpufreq_driver->owner);
994 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
998 policy->last_cpu = policy->cpu;
1001 for_each_cpu(j, policy->cpus)
1002 per_cpu(cpufreq_policy_cpu, j) = cpu;
1004 #ifdef CONFIG_CPU_FREQ_TABLE
1005 cpufreq_frequency_table_update_policy_cpu(policy);
1007 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1008 CPUFREQ_UPDATE_POLICY_CPU, policy);
1012 * __cpufreq_remove_dev - remove a CPU device
1014 * Removes the cpufreq interface for a CPU device.
1015 * Caller should already have policy_rwsem in write mode for this CPU.
1016 * This routine frees the rwsem before returning.
1018 static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1020 unsigned int cpu = dev->id, ret, cpus;
1021 unsigned long flags;
1022 struct cpufreq_policy *data;
1023 struct kobject *kobj;
1024 struct completion *cmp;
1025 struct device *cpu_dev;
1027 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1029 write_lock_irqsave(&cpufreq_driver_lock, flags);
1031 data = per_cpu(cpufreq_cpu_data, cpu);
1032 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1034 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1037 pr_debug("%s: No cpu_data found\n", __func__);
1041 if (cpufreq_driver->target)
1042 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1044 #ifdef CONFIG_HOTPLUG_CPU
1045 if (!cpufreq_driver->setpolicy)
1046 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1047 data->governor->name, CPUFREQ_NAME_LEN);
1050 WARN_ON(lock_policy_rwsem_write(cpu));
1051 cpus = cpumask_weight(data->cpus);
1054 cpumask_clear_cpu(cpu, data->cpus);
1055 unlock_policy_rwsem_write(cpu);
1057 if (cpu != data->cpu) {
1058 sysfs_remove_link(&dev->kobj, "cpufreq");
1059 } else if (cpus > 1) {
1060 /* first sibling now owns the new sysfs dir */
1061 cpu_dev = get_cpu_device(cpumask_first(data->cpus));
1062 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1063 ret = kobject_move(&data->kobj, &cpu_dev->kobj);
1065 pr_err("%s: Failed to move kobj: %d", __func__, ret);
1067 WARN_ON(lock_policy_rwsem_write(cpu));
1068 cpumask_set_cpu(cpu, data->cpus);
1070 write_lock_irqsave(&cpufreq_driver_lock, flags);
1071 per_cpu(cpufreq_cpu_data, cpu) = data;
1072 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1074 unlock_policy_rwsem_write(cpu);
1076 ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
1081 WARN_ON(lock_policy_rwsem_write(cpu));
1082 update_policy_cpu(data, cpu_dev->id);
1083 unlock_policy_rwsem_write(cpu);
1084 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1085 __func__, cpu_dev->id, cpu);
1088 if ((cpus == 1) && (cpufreq_driver->target))
1089 __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
1091 pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
1092 cpufreq_cpu_put(data);
1094 /* If cpu is last user of policy, free policy */
1096 lock_policy_rwsem_read(cpu);
1098 cmp = &data->kobj_unregister;
1099 unlock_policy_rwsem_read(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 if (cpufreq_driver->exit)
1111 cpufreq_driver->exit(data);
1113 free_cpumask_var(data->related_cpus);
1114 free_cpumask_var(data->cpus);
1116 } else if (cpufreq_driver->target) {
1117 __cpufreq_governor(data, CPUFREQ_GOV_START);
1118 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1121 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1126 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1128 unsigned int cpu = dev->id;
1131 if (cpu_is_offline(cpu))
1134 retval = __cpufreq_remove_dev(dev, sif);
1139 static void handle_update(struct work_struct *work)
1141 struct cpufreq_policy *policy =
1142 container_of(work, struct cpufreq_policy, update);
1143 unsigned int cpu = policy->cpu;
1144 pr_debug("handle_update for cpu %u called\n", cpu);
1145 cpufreq_update_policy(cpu);
1149 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1151 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1152 * @new_freq: CPU frequency the CPU actually runs at
1154 * We adjust to current frequency first, and need to clean up later.
1155 * So either call to cpufreq_update_policy() or schedule handle_update()).
1157 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1158 unsigned int new_freq)
1160 struct cpufreq_policy *policy;
1161 struct cpufreq_freqs freqs;
1162 unsigned long flags;
1165 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1166 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1168 freqs.old = old_freq;
1169 freqs.new = new_freq;
1171 read_lock_irqsave(&cpufreq_driver_lock, flags);
1172 policy = per_cpu(cpufreq_cpu_data, cpu);
1173 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1175 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
1176 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
1181 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1184 * This is the last known freq, without actually getting it from the driver.
1185 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1187 unsigned int cpufreq_quick_get(unsigned int cpu)
1189 struct cpufreq_policy *policy;
1190 unsigned int ret_freq = 0;
1192 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1193 return cpufreq_driver->get(cpu);
1195 policy = cpufreq_cpu_get(cpu);
1197 ret_freq = policy->cur;
1198 cpufreq_cpu_put(policy);
1203 EXPORT_SYMBOL(cpufreq_quick_get);
1206 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1209 * Just return the max possible frequency for a given CPU.
1211 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1213 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1214 unsigned int ret_freq = 0;
1217 ret_freq = policy->max;
1218 cpufreq_cpu_put(policy);
1223 EXPORT_SYMBOL(cpufreq_quick_get_max);
1226 static unsigned int __cpufreq_get(unsigned int cpu)
1228 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1229 unsigned int ret_freq = 0;
1231 if (!cpufreq_driver->get)
1234 ret_freq = cpufreq_driver->get(cpu);
1236 if (ret_freq && policy->cur &&
1237 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1238 /* verify no discrepancy between actual and
1239 saved value exists */
1240 if (unlikely(ret_freq != policy->cur)) {
1241 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1242 schedule_work(&policy->update);
1250 * cpufreq_get - get the current CPU frequency (in kHz)
1253 * Get the CPU current (static) CPU frequency
1255 unsigned int cpufreq_get(unsigned int cpu)
1257 unsigned int ret_freq = 0;
1258 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1263 if (unlikely(lock_policy_rwsem_read(cpu)))
1266 ret_freq = __cpufreq_get(cpu);
1268 unlock_policy_rwsem_read(cpu);
1271 cpufreq_cpu_put(policy);
1275 EXPORT_SYMBOL(cpufreq_get);
1277 static struct subsys_interface cpufreq_interface = {
1279 .subsys = &cpu_subsys,
1280 .add_dev = cpufreq_add_dev,
1281 .remove_dev = cpufreq_remove_dev,
1286 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1288 * This function is only executed for the boot processor. The other CPUs
1289 * have been put offline by means of CPU hotplug.
1291 static int cpufreq_bp_suspend(void)
1295 int cpu = smp_processor_id();
1296 struct cpufreq_policy *cpu_policy;
1298 pr_debug("suspending cpu %u\n", cpu);
1300 /* If there's no policy for the boot CPU, we have nothing to do. */
1301 cpu_policy = cpufreq_cpu_get(cpu);
1305 if (cpufreq_driver->suspend) {
1306 ret = cpufreq_driver->suspend(cpu_policy);
1308 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1309 "step on CPU %u\n", cpu_policy->cpu);
1312 cpufreq_cpu_put(cpu_policy);
1317 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1319 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1320 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1321 * restored. It will verify that the current freq is in sync with
1322 * what we believe it to be. This is a bit later than when it
1323 * should be, but nonethteless it's better than calling
1324 * cpufreq_driver->get() here which might re-enable interrupts...
1326 * This function is only executed for the boot CPU. The other CPUs have not
1327 * been turned on yet.
1329 static void cpufreq_bp_resume(void)
1333 int cpu = smp_processor_id();
1334 struct cpufreq_policy *cpu_policy;
1336 pr_debug("resuming cpu %u\n", cpu);
1338 /* If there's no policy for the boot CPU, we have nothing to do. */
1339 cpu_policy = cpufreq_cpu_get(cpu);
1343 if (cpufreq_driver->resume) {
1344 ret = cpufreq_driver->resume(cpu_policy);
1346 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1347 "step on CPU %u\n", cpu_policy->cpu);
1352 schedule_work(&cpu_policy->update);
1355 cpufreq_cpu_put(cpu_policy);
1358 static struct syscore_ops cpufreq_syscore_ops = {
1359 .suspend = cpufreq_bp_suspend,
1360 .resume = cpufreq_bp_resume,
1364 * cpufreq_get_current_driver - return current driver's name
1366 * Return the name string of the currently loaded cpufreq driver
1369 const char *cpufreq_get_current_driver(void)
1372 return cpufreq_driver->name;
1376 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1378 /*********************************************************************
1379 * NOTIFIER LISTS INTERFACE *
1380 *********************************************************************/
1383 * cpufreq_register_notifier - register a driver with cpufreq
1384 * @nb: notifier function to register
1385 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1387 * Add a driver to one of two lists: either a list of drivers that
1388 * are notified about clock rate changes (once before and once after
1389 * the transition), or a list of drivers that are notified about
1390 * changes in cpufreq policy.
1392 * This function may sleep, and has the same return conditions as
1393 * blocking_notifier_chain_register.
1395 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1399 if (cpufreq_disabled())
1402 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1405 case CPUFREQ_TRANSITION_NOTIFIER:
1406 ret = srcu_notifier_chain_register(
1407 &cpufreq_transition_notifier_list, nb);
1409 case CPUFREQ_POLICY_NOTIFIER:
1410 ret = blocking_notifier_chain_register(
1411 &cpufreq_policy_notifier_list, nb);
1419 EXPORT_SYMBOL(cpufreq_register_notifier);
1423 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1424 * @nb: notifier block to be unregistered
1425 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1427 * Remove a driver from the CPU frequency notifier list.
1429 * This function may sleep, and has the same return conditions as
1430 * blocking_notifier_chain_unregister.
1432 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1436 if (cpufreq_disabled())
1440 case CPUFREQ_TRANSITION_NOTIFIER:
1441 ret = srcu_notifier_chain_unregister(
1442 &cpufreq_transition_notifier_list, nb);
1444 case CPUFREQ_POLICY_NOTIFIER:
1445 ret = blocking_notifier_chain_unregister(
1446 &cpufreq_policy_notifier_list, nb);
1454 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1457 /*********************************************************************
1459 *********************************************************************/
1462 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1463 unsigned int target_freq,
1464 unsigned int relation)
1466 int retval = -EINVAL;
1467 unsigned int old_target_freq = target_freq;
1469 if (cpufreq_disabled())
1472 /* Make sure that target_freq is within supported range */
1473 if (target_freq > policy->max)
1474 target_freq = policy->max;
1475 if (target_freq < policy->min)
1476 target_freq = policy->min;
1478 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1479 policy->cpu, target_freq, relation, old_target_freq);
1481 if (target_freq == policy->cur)
1484 if (cpufreq_driver->target)
1485 retval = cpufreq_driver->target(policy, target_freq, relation);
1489 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1491 int cpufreq_driver_target(struct cpufreq_policy *policy,
1492 unsigned int target_freq,
1493 unsigned int relation)
1497 policy = cpufreq_cpu_get(policy->cpu);
1501 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1504 ret = __cpufreq_driver_target(policy, target_freq, relation);
1506 unlock_policy_rwsem_write(policy->cpu);
1509 cpufreq_cpu_put(policy);
1513 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1515 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1519 if (cpufreq_disabled())
1522 if (!cpufreq_driver->getavg)
1525 policy = cpufreq_cpu_get(policy->cpu);
1529 ret = cpufreq_driver->getavg(policy, cpu);
1531 cpufreq_cpu_put(policy);
1534 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1537 * when "event" is CPUFREQ_GOV_LIMITS
1540 static int __cpufreq_governor(struct cpufreq_policy *policy,
1545 /* Only must be defined when default governor is known to have latency
1546 restrictions, like e.g. conservative or ondemand.
1547 That this is the case is already ensured in Kconfig
1549 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1550 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1552 struct cpufreq_governor *gov = NULL;
1555 if (policy->governor->max_transition_latency &&
1556 policy->cpuinfo.transition_latency >
1557 policy->governor->max_transition_latency) {
1561 printk(KERN_WARNING "%s governor failed, too long"
1562 " transition latency of HW, fallback"
1563 " to %s governor\n",
1564 policy->governor->name,
1566 policy->governor = gov;
1570 if (!try_module_get(policy->governor->owner))
1573 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1574 policy->cpu, event);
1575 ret = policy->governor->governor(policy, event);
1578 if (event == CPUFREQ_GOV_POLICY_INIT)
1579 policy->governor->initialized++;
1580 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1581 policy->governor->initialized--;
1584 /* we keep one module reference alive for
1585 each CPU governed by this CPU */
1586 if ((event != CPUFREQ_GOV_START) || ret)
1587 module_put(policy->governor->owner);
1588 if ((event == CPUFREQ_GOV_STOP) && !ret)
1589 module_put(policy->governor->owner);
1595 int cpufreq_register_governor(struct cpufreq_governor *governor)
1602 if (cpufreq_disabled())
1605 mutex_lock(&cpufreq_governor_mutex);
1607 governor->initialized = 0;
1609 if (__find_governor(governor->name) == NULL) {
1611 list_add(&governor->governor_list, &cpufreq_governor_list);
1614 mutex_unlock(&cpufreq_governor_mutex);
1617 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1620 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1622 #ifdef CONFIG_HOTPLUG_CPU
1629 if (cpufreq_disabled())
1632 #ifdef CONFIG_HOTPLUG_CPU
1633 for_each_present_cpu(cpu) {
1634 if (cpu_online(cpu))
1636 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1637 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1641 mutex_lock(&cpufreq_governor_mutex);
1642 list_del(&governor->governor_list);
1643 mutex_unlock(&cpufreq_governor_mutex);
1646 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1650 /*********************************************************************
1651 * POLICY INTERFACE *
1652 *********************************************************************/
1655 * cpufreq_get_policy - get the current cpufreq_policy
1656 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1659 * Reads the current cpufreq policy.
1661 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1663 struct cpufreq_policy *cpu_policy;
1667 cpu_policy = cpufreq_cpu_get(cpu);
1671 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1673 cpufreq_cpu_put(cpu_policy);
1676 EXPORT_SYMBOL(cpufreq_get_policy);
1680 * data : current policy.
1681 * policy : policy to be set.
1683 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1684 struct cpufreq_policy *policy)
1686 int ret = 0, failed = 1;
1688 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1689 policy->min, policy->max);
1691 memcpy(&policy->cpuinfo, &data->cpuinfo,
1692 sizeof(struct cpufreq_cpuinfo));
1694 if (policy->min > data->max || policy->max < data->min) {
1699 /* verify the cpu speed can be set within this limit */
1700 ret = cpufreq_driver->verify(policy);
1704 /* adjust if necessary - all reasons */
1705 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1706 CPUFREQ_ADJUST, policy);
1708 /* adjust if necessary - hardware incompatibility*/
1709 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1710 CPUFREQ_INCOMPATIBLE, policy);
1712 /* verify the cpu speed can be set within this limit,
1713 which might be different to the first one */
1714 ret = cpufreq_driver->verify(policy);
1718 /* notification of the new policy */
1719 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1720 CPUFREQ_NOTIFY, policy);
1722 data->min = policy->min;
1723 data->max = policy->max;
1725 pr_debug("new min and max freqs are %u - %u kHz\n",
1726 data->min, data->max);
1728 if (cpufreq_driver->setpolicy) {
1729 data->policy = policy->policy;
1730 pr_debug("setting range\n");
1731 ret = cpufreq_driver->setpolicy(policy);
1733 if (policy->governor != data->governor) {
1734 /* save old, working values */
1735 struct cpufreq_governor *old_gov = data->governor;
1737 pr_debug("governor switch\n");
1739 /* end old governor */
1740 if (data->governor) {
1741 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1742 unlock_policy_rwsem_write(policy->cpu);
1743 __cpufreq_governor(data,
1744 CPUFREQ_GOV_POLICY_EXIT);
1745 lock_policy_rwsem_write(policy->cpu);
1748 /* start new governor */
1749 data->governor = policy->governor;
1750 if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) {
1751 if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1754 unlock_policy_rwsem_write(policy->cpu);
1755 __cpufreq_governor(data,
1756 CPUFREQ_GOV_POLICY_EXIT);
1757 lock_policy_rwsem_write(policy->cpu);
1762 /* new governor failed, so re-start old one */
1763 pr_debug("starting governor %s failed\n",
1764 data->governor->name);
1766 data->governor = old_gov;
1767 __cpufreq_governor(data,
1768 CPUFREQ_GOV_POLICY_INIT);
1769 __cpufreq_governor(data,
1775 /* might be a policy change, too, so fall through */
1777 pr_debug("governor: change or update limits\n");
1778 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1786 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1787 * @cpu: CPU which shall be re-evaluated
1789 * Useful for policy notifiers which have different necessities
1790 * at different times.
1792 int cpufreq_update_policy(unsigned int cpu)
1794 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1795 struct cpufreq_policy policy;
1803 if (unlikely(lock_policy_rwsem_write(cpu))) {
1808 pr_debug("updating policy for CPU %u\n", cpu);
1809 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1810 policy.min = data->user_policy.min;
1811 policy.max = data->user_policy.max;
1812 policy.policy = data->user_policy.policy;
1813 policy.governor = data->user_policy.governor;
1815 /* BIOS might change freq behind our back
1816 -> ask driver for current freq and notify governors about a change */
1817 if (cpufreq_driver->get) {
1818 policy.cur = cpufreq_driver->get(cpu);
1820 pr_debug("Driver did not initialize current freq");
1821 data->cur = policy.cur;
1823 if (data->cur != policy.cur && cpufreq_driver->target)
1824 cpufreq_out_of_sync(cpu, data->cur,
1829 ret = __cpufreq_set_policy(data, &policy);
1831 unlock_policy_rwsem_write(cpu);
1834 cpufreq_cpu_put(data);
1838 EXPORT_SYMBOL(cpufreq_update_policy);
1840 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1841 unsigned long action, void *hcpu)
1843 unsigned int cpu = (unsigned long)hcpu;
1846 dev = get_cpu_device(cpu);
1850 cpufreq_add_dev(dev, NULL);
1852 case CPU_DOWN_PREPARE:
1853 case CPU_UP_CANCELED_FROZEN:
1854 __cpufreq_remove_dev(dev, NULL);
1856 case CPU_DOWN_FAILED:
1857 cpufreq_add_dev(dev, NULL);
1864 static struct notifier_block __refdata cpufreq_cpu_notifier = {
1865 .notifier_call = cpufreq_cpu_callback,
1868 /*********************************************************************
1869 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1870 *********************************************************************/
1873 * cpufreq_register_driver - register a CPU Frequency driver
1874 * @driver_data: A struct cpufreq_driver containing the values#
1875 * submitted by the CPU Frequency driver.
1877 * Registers a CPU Frequency driver to this core code. This code
1878 * returns zero on success, -EBUSY when another driver got here first
1879 * (and isn't unregistered in the meantime).
1882 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1884 unsigned long flags;
1887 if (cpufreq_disabled())
1890 if (!driver_data || !driver_data->verify || !driver_data->init ||
1891 ((!driver_data->setpolicy) && (!driver_data->target)))
1894 pr_debug("trying to register driver %s\n", driver_data->name);
1896 if (driver_data->setpolicy)
1897 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1899 write_lock_irqsave(&cpufreq_driver_lock, flags);
1900 if (cpufreq_driver) {
1901 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1904 cpufreq_driver = driver_data;
1905 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1907 ret = subsys_interface_register(&cpufreq_interface);
1909 goto err_null_driver;
1911 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1915 /* check for at least one working CPU */
1916 for (i = 0; i < nr_cpu_ids; i++)
1917 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1922 /* if all ->init() calls failed, unregister */
1924 pr_debug("no CPU initialized for driver %s\n",
1930 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1931 pr_debug("driver %s up and running\n", driver_data->name);
1935 subsys_interface_unregister(&cpufreq_interface);
1937 write_lock_irqsave(&cpufreq_driver_lock, flags);
1938 cpufreq_driver = NULL;
1939 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1942 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1946 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1948 * Unregister the current CPUFreq driver. Only call this if you have
1949 * the right to do so, i.e. if you have succeeded in initialising before!
1950 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1951 * currently not initialised.
1953 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1955 unsigned long flags;
1957 if (!cpufreq_driver || (driver != cpufreq_driver))
1960 pr_debug("unregistering driver %s\n", driver->name);
1962 subsys_interface_unregister(&cpufreq_interface);
1963 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1965 write_lock_irqsave(&cpufreq_driver_lock, flags);
1966 cpufreq_driver = NULL;
1967 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1971 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1973 static int __init cpufreq_core_init(void)
1977 if (cpufreq_disabled())
1980 for_each_possible_cpu(cpu) {
1981 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1982 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1985 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
1986 BUG_ON(!cpufreq_global_kobject);
1987 register_syscore_ops(&cpufreq_syscore_ops);
1991 core_initcall(cpufreq_core_init);