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>
32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
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(struct cpufreq_governor *, 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.
65 static DEFINE_PER_CPU(int, policy_cpu);
66 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
68 #define lock_policy_rwsem(mode, cpu) \
69 int lock_policy_rwsem_##mode \
72 int policy_cpu = per_cpu(policy_cpu, cpu); \
73 BUG_ON(policy_cpu == -1); \
74 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
75 if (unlikely(!cpu_online(cpu))) { \
76 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
83 lock_policy_rwsem(read, cpu);
84 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read);
86 lock_policy_rwsem(write, cpu);
87 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write);
89 void unlock_policy_rwsem_read(int cpu)
91 int policy_cpu = per_cpu(policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
95 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read);
97 void unlock_policy_rwsem_write(int cpu)
99 int policy_cpu = per_cpu(policy_cpu, cpu);
100 BUG_ON(policy_cpu == -1);
101 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
103 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write);
106 /* internal prototypes */
107 static int __cpufreq_governor(struct cpufreq_policy *policy,
109 static unsigned int __cpufreq_get(unsigned int cpu);
110 static void handle_update(struct work_struct *work);
113 * Two notifier lists: the "policy" list is involved in the
114 * validation process for a new CPU frequency policy; the
115 * "transition" list for kernel code that needs to handle
116 * changes to devices when the CPU clock speed changes.
117 * The mutex locks both lists.
119 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
120 static struct srcu_notifier_head cpufreq_transition_notifier_list;
122 static bool init_cpufreq_transition_notifier_list_called;
123 static int __init init_cpufreq_transition_notifier_list(void)
125 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
126 init_cpufreq_transition_notifier_list_called = true;
129 pure_initcall(init_cpufreq_transition_notifier_list);
131 static LIST_HEAD(cpufreq_governor_list);
132 static DEFINE_MUTEX(cpufreq_governor_mutex);
134 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
136 struct cpufreq_policy *data;
139 if (cpu >= nr_cpu_ids)
142 /* get the cpufreq driver */
143 spin_lock_irqsave(&cpufreq_driver_lock, flags);
148 if (!try_module_get(cpufreq_driver->owner))
153 data = per_cpu(cpufreq_cpu_data, cpu);
156 goto err_out_put_module;
158 if (!kobject_get(&data->kobj))
159 goto err_out_put_module;
161 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
165 module_put(cpufreq_driver->owner);
167 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
171 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
174 void cpufreq_cpu_put(struct cpufreq_policy *data)
176 kobject_put(&data->kobj);
177 module_put(cpufreq_driver->owner);
179 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
182 /*********************************************************************
183 * UNIFIED DEBUG HELPERS *
184 *********************************************************************/
185 #ifdef CONFIG_CPU_FREQ_DEBUG
187 /* what part(s) of the CPUfreq subsystem are debugged? */
188 static unsigned int debug;
190 /* is the debug output ratelimit'ed using printk_ratelimit? User can
191 * set or modify this value.
193 static unsigned int debug_ratelimit = 1;
195 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
196 * loading of a cpufreq driver, temporarily disabled when a new policy
197 * is set, and disabled upon cpufreq driver removal
199 static unsigned int disable_ratelimit = 1;
200 static DEFINE_SPINLOCK(disable_ratelimit_lock);
202 static void cpufreq_debug_enable_ratelimit(void)
206 spin_lock_irqsave(&disable_ratelimit_lock, flags);
207 if (disable_ratelimit)
209 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
212 static void cpufreq_debug_disable_ratelimit(void)
216 spin_lock_irqsave(&disable_ratelimit_lock, flags);
218 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
221 void cpufreq_debug_printk(unsigned int type, const char *prefix,
222 const char *fmt, ...)
231 spin_lock_irqsave(&disable_ratelimit_lock, flags);
232 if (!disable_ratelimit && debug_ratelimit
233 && !printk_ratelimit()) {
234 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
237 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
239 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
242 len += vsnprintf(&s[len], (256 - len), fmt, args);
250 EXPORT_SYMBOL(cpufreq_debug_printk);
253 module_param(debug, uint, 0644);
254 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
255 " 2 to debug drivers, and 4 to debug governors.");
257 module_param(debug_ratelimit, uint, 0644);
258 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
259 " set to 0 to disable ratelimiting.");
261 #else /* !CONFIG_CPU_FREQ_DEBUG */
263 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
264 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
266 #endif /* CONFIG_CPU_FREQ_DEBUG */
269 /*********************************************************************
270 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
271 *********************************************************************/
274 * adjust_jiffies - adjust the system "loops_per_jiffy"
276 * This function alters the system "loops_per_jiffy" for the clock
277 * speed change. Note that loops_per_jiffy cannot be updated on SMP
278 * systems as each CPU might be scaled differently. So, use the arch
279 * per-CPU loops_per_jiffy value wherever possible.
282 static unsigned long l_p_j_ref;
283 static unsigned int l_p_j_ref_freq;
285 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
287 if (ci->flags & CPUFREQ_CONST_LOOPS)
290 if (!l_p_j_ref_freq) {
291 l_p_j_ref = loops_per_jiffy;
292 l_p_j_ref_freq = ci->old;
293 dprintk("saving %lu as reference value for loops_per_jiffy; "
294 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
296 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
297 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
298 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
299 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
301 dprintk("scaling loops_per_jiffy to %lu "
302 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
306 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
314 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
315 * on frequency transition.
317 * This function calls the transition notifiers and the "adjust_jiffies"
318 * function. It is called twice on all CPU frequency changes that have
321 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
323 struct cpufreq_policy *policy;
325 BUG_ON(irqs_disabled());
327 freqs->flags = cpufreq_driver->flags;
328 dprintk("notification %u of frequency transition to %u kHz\n",
331 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
334 case CPUFREQ_PRECHANGE:
335 /* detect if the driver reported a value as "old frequency"
336 * which is not equal to what the cpufreq core thinks is
339 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
340 if ((policy) && (policy->cpu == freqs->cpu) &&
341 (policy->cur) && (policy->cur != freqs->old)) {
342 dprintk("Warning: CPU frequency is"
343 " %u, cpufreq assumed %u kHz.\n",
344 freqs->old, policy->cur);
345 freqs->old = policy->cur;
348 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
349 CPUFREQ_PRECHANGE, freqs);
350 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
353 case CPUFREQ_POSTCHANGE:
354 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
355 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
356 CPUFREQ_POSTCHANGE, freqs);
357 if (likely(policy) && likely(policy->cpu == freqs->cpu))
358 policy->cur = freqs->new;
362 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
366 /*********************************************************************
368 *********************************************************************/
370 static struct cpufreq_governor *__find_governor(const char *str_governor)
372 struct cpufreq_governor *t;
374 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
375 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
382 * cpufreq_parse_governor - parse a governor string
384 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
385 struct cpufreq_governor **governor)
392 if (cpufreq_driver->setpolicy) {
393 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
394 *policy = CPUFREQ_POLICY_PERFORMANCE;
396 } else if (!strnicmp(str_governor, "powersave",
398 *policy = CPUFREQ_POLICY_POWERSAVE;
401 } else if (cpufreq_driver->target) {
402 struct cpufreq_governor *t;
404 mutex_lock(&cpufreq_governor_mutex);
406 t = __find_governor(str_governor);
409 char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
415 mutex_unlock(&cpufreq_governor_mutex);
416 ret = request_module("%s", name);
417 mutex_lock(&cpufreq_governor_mutex);
420 t = __find_governor(str_governor);
431 mutex_unlock(&cpufreq_governor_mutex);
439 * cpufreq_per_cpu_attr_read() / show_##file_name() -
440 * print out cpufreq information
442 * Write out information from cpufreq_driver->policy[cpu]; object must be
446 #define show_one(file_name, object) \
447 static ssize_t show_##file_name \
448 (struct cpufreq_policy *policy, char *buf) \
450 return sprintf(buf, "%u\n", policy->object); \
453 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
454 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
455 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
456 show_one(scaling_min_freq, min);
457 show_one(scaling_max_freq, max);
458 show_one(scaling_cur_freq, cur);
460 static int __cpufreq_set_policy(struct cpufreq_policy *data,
461 struct cpufreq_policy *policy);
464 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
466 #define store_one(file_name, object) \
467 static ssize_t store_##file_name \
468 (struct cpufreq_policy *policy, const char *buf, size_t count) \
470 unsigned int ret = -EINVAL; \
471 struct cpufreq_policy new_policy; \
473 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
477 ret = sscanf(buf, "%u", &new_policy.object); \
481 ret = __cpufreq_set_policy(policy, &new_policy); \
482 policy->user_policy.object = policy->object; \
484 return ret ? ret : count; \
487 store_one(scaling_min_freq, min);
488 store_one(scaling_max_freq, max);
491 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
493 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
496 unsigned int cur_freq = __cpufreq_get(policy->cpu);
498 return sprintf(buf, "<unknown>");
499 return sprintf(buf, "%u\n", cur_freq);
504 * show_scaling_governor - show the current policy for the specified CPU
506 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
508 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
509 return sprintf(buf, "powersave\n");
510 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
511 return sprintf(buf, "performance\n");
512 else if (policy->governor)
513 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
514 policy->governor->name);
520 * store_scaling_governor - store policy for the specified CPU
522 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
523 const char *buf, size_t count)
525 unsigned int ret = -EINVAL;
526 char str_governor[16];
527 struct cpufreq_policy new_policy;
529 ret = cpufreq_get_policy(&new_policy, policy->cpu);
533 ret = sscanf(buf, "%15s", str_governor);
537 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
538 &new_policy.governor))
541 /* Do not use cpufreq_set_policy here or the user_policy.max
542 will be wrongly overridden */
543 ret = __cpufreq_set_policy(policy, &new_policy);
545 policy->user_policy.policy = policy->policy;
546 policy->user_policy.governor = policy->governor;
555 * show_scaling_driver - show the cpufreq driver currently loaded
557 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
559 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
563 * show_scaling_available_governors - show the available CPUfreq governors
565 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
569 struct cpufreq_governor *t;
571 if (!cpufreq_driver->target) {
572 i += sprintf(buf, "performance powersave");
576 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
577 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
578 - (CPUFREQ_NAME_LEN + 2)))
580 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
583 i += sprintf(&buf[i], "\n");
587 static ssize_t show_cpus(const struct cpumask *mask, char *buf)
592 for_each_cpu(cpu, mask) {
594 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
595 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
596 if (i >= (PAGE_SIZE - 5))
599 i += sprintf(&buf[i], "\n");
604 * show_related_cpus - show the CPUs affected by each transition even if
605 * hw coordination is in use
607 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
609 if (cpumask_empty(policy->related_cpus))
610 return show_cpus(policy->cpus, buf);
611 return show_cpus(policy->related_cpus, buf);
615 * show_affected_cpus - show the CPUs affected by each transition
617 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
619 return show_cpus(policy->cpus, buf);
622 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
623 const char *buf, size_t count)
625 unsigned int freq = 0;
628 if (!policy->governor || !policy->governor->store_setspeed)
631 ret = sscanf(buf, "%u", &freq);
635 policy->governor->store_setspeed(policy, freq);
640 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
642 if (!policy->governor || !policy->governor->show_setspeed)
643 return sprintf(buf, "<unsupported>\n");
645 return policy->governor->show_setspeed(policy, buf);
648 #define define_one_ro(_name) \
649 static struct freq_attr _name = \
650 __ATTR(_name, 0444, show_##_name, NULL)
652 #define define_one_ro0400(_name) \
653 static struct freq_attr _name = \
654 __ATTR(_name, 0400, show_##_name, NULL)
656 #define define_one_rw(_name) \
657 static struct freq_attr _name = \
658 __ATTR(_name, 0644, show_##_name, store_##_name)
660 define_one_ro0400(cpuinfo_cur_freq);
661 define_one_ro(cpuinfo_min_freq);
662 define_one_ro(cpuinfo_max_freq);
663 define_one_ro(cpuinfo_transition_latency);
664 define_one_ro(scaling_available_governors);
665 define_one_ro(scaling_driver);
666 define_one_ro(scaling_cur_freq);
667 define_one_ro(related_cpus);
668 define_one_ro(affected_cpus);
669 define_one_rw(scaling_min_freq);
670 define_one_rw(scaling_max_freq);
671 define_one_rw(scaling_governor);
672 define_one_rw(scaling_setspeed);
674 static struct attribute *default_attrs[] = {
675 &cpuinfo_min_freq.attr,
676 &cpuinfo_max_freq.attr,
677 &cpuinfo_transition_latency.attr,
678 &scaling_min_freq.attr,
679 &scaling_max_freq.attr,
682 &scaling_governor.attr,
683 &scaling_driver.attr,
684 &scaling_available_governors.attr,
685 &scaling_setspeed.attr,
689 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
690 #define to_attr(a) container_of(a, struct freq_attr, attr)
692 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
694 struct cpufreq_policy *policy = to_policy(kobj);
695 struct freq_attr *fattr = to_attr(attr);
696 ssize_t ret = -EINVAL;
697 policy = cpufreq_cpu_get(policy->cpu);
701 if (lock_policy_rwsem_read(policy->cpu) < 0)
705 ret = fattr->show(policy, buf);
709 unlock_policy_rwsem_read(policy->cpu);
711 cpufreq_cpu_put(policy);
716 static ssize_t store(struct kobject *kobj, struct attribute *attr,
717 const char *buf, size_t count)
719 struct cpufreq_policy *policy = to_policy(kobj);
720 struct freq_attr *fattr = to_attr(attr);
721 ssize_t ret = -EINVAL;
722 policy = cpufreq_cpu_get(policy->cpu);
726 if (lock_policy_rwsem_write(policy->cpu) < 0)
730 ret = fattr->store(policy, buf, count);
734 unlock_policy_rwsem_write(policy->cpu);
736 cpufreq_cpu_put(policy);
741 static void cpufreq_sysfs_release(struct kobject *kobj)
743 struct cpufreq_policy *policy = to_policy(kobj);
744 dprintk("last reference is dropped\n");
745 complete(&policy->kobj_unregister);
748 static struct sysfs_ops sysfs_ops = {
753 static struct kobj_type ktype_cpufreq = {
754 .sysfs_ops = &sysfs_ops,
755 .default_attrs = default_attrs,
756 .release = cpufreq_sysfs_release,
761 * cpufreq_add_dev - add a CPU device
763 * Adds the cpufreq interface for a CPU device.
765 * The Oracle says: try running cpufreq registration/unregistration concurrently
766 * with with cpu hotplugging and all hell will break loose. Tried to clean this
767 * mess up, but more thorough testing is needed. - Mathieu
769 static int cpufreq_add_dev(struct sys_device *sys_dev)
771 unsigned int cpu = sys_dev->id;
773 struct cpufreq_policy new_policy;
774 struct cpufreq_policy *policy;
775 struct freq_attr **drv_attr;
776 struct sys_device *cpu_sys_dev;
780 if (cpu_is_offline(cpu))
783 cpufreq_debug_disable_ratelimit();
784 dprintk("adding CPU %u\n", cpu);
787 /* check whether a different CPU already registered this
788 * CPU because it is in the same boat. */
789 policy = cpufreq_cpu_get(cpu);
790 if (unlikely(policy)) {
791 cpufreq_cpu_put(policy);
792 cpufreq_debug_enable_ratelimit();
797 if (!try_module_get(cpufreq_driver->owner)) {
802 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
807 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) {
809 goto err_free_policy;
811 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
813 goto err_free_cpumask;
817 cpumask_copy(policy->cpus, cpumask_of(cpu));
819 /* Initially set CPU itself as the policy_cpu */
820 per_cpu(policy_cpu, cpu) = cpu;
821 ret = (lock_policy_rwsem_write(cpu) < 0);
824 init_completion(&policy->kobj_unregister);
825 INIT_WORK(&policy->update, handle_update);
827 /* Set governor before ->init, so that driver could check it */
828 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
829 /* call driver. From then on the cpufreq must be able
830 * to accept all calls to ->verify and ->setpolicy for this CPU
832 ret = cpufreq_driver->init(policy);
834 dprintk("initialization failed\n");
835 goto err_unlock_policy;
837 policy->user_policy.min = policy->min;
838 policy->user_policy.max = policy->max;
840 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
841 CPUFREQ_START, policy);
845 #ifdef CONFIG_HOTPLUG_CPU
846 if (per_cpu(cpufreq_cpu_governor, cpu)) {
847 policy->governor = per_cpu(cpufreq_cpu_governor, cpu);
848 dprintk("Restoring governor %s for cpu %d\n",
849 policy->governor->name, cpu);
853 for_each_cpu(j, policy->cpus) {
854 struct cpufreq_policy *managed_policy;
859 /* Check for existing affected CPUs.
860 * They may not be aware of it due to CPU Hotplug.
862 managed_policy = cpufreq_cpu_get(j);
863 if (unlikely(managed_policy)) {
865 /* Set proper policy_cpu */
866 unlock_policy_rwsem_write(cpu);
867 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
869 if (lock_policy_rwsem_write(cpu) < 0) {
870 /* Should not go through policy unlock path */
871 if (cpufreq_driver->exit)
872 cpufreq_driver->exit(policy);
874 cpufreq_cpu_put(managed_policy);
875 goto err_free_cpumask;
878 spin_lock_irqsave(&cpufreq_driver_lock, flags);
879 cpumask_copy(managed_policy->cpus, policy->cpus);
880 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
881 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
883 dprintk("CPU already managed, adding link\n");
884 ret = sysfs_create_link(&sys_dev->kobj,
885 &managed_policy->kobj,
888 cpufreq_cpu_put(managed_policy);
890 * Success. We only needed to be added to the mask.
891 * Call driver->exit() because only the cpu parent of
892 * the kobj needed to call init().
894 goto out_driver_exit; /* call driver->exit() */
898 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
900 /* prepare interface data */
901 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
904 goto out_driver_exit;
906 /* set up files for this cpu device */
907 drv_attr = cpufreq_driver->attr;
908 while ((drv_attr) && (*drv_attr)) {
909 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
911 goto err_out_kobj_put;
914 if (cpufreq_driver->get) {
915 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
917 goto err_out_kobj_put;
919 if (cpufreq_driver->target) {
920 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
922 goto err_out_kobj_put;
925 spin_lock_irqsave(&cpufreq_driver_lock, flags);
926 for_each_cpu(j, policy->cpus) {
929 per_cpu(cpufreq_cpu_data, j) = policy;
930 per_cpu(policy_cpu, j) = policy->cpu;
932 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
934 /* symlink affected CPUs */
935 for_each_cpu(j, policy->cpus) {
936 struct cpufreq_policy *managed_policy;
943 dprintk("CPU %u already managed, adding link\n", j);
944 managed_policy = cpufreq_cpu_get(cpu);
945 cpu_sys_dev = get_cpu_sysdev(j);
946 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
949 cpufreq_cpu_put(managed_policy);
950 goto err_out_unregister;
954 policy->governor = NULL; /* to assure that the starting sequence is
955 * run in cpufreq_set_policy */
957 /* set default policy */
958 ret = __cpufreq_set_policy(policy, &new_policy);
959 policy->user_policy.policy = policy->policy;
960 policy->user_policy.governor = policy->governor;
963 dprintk("setting policy failed\n");
964 goto err_out_unregister;
967 unlock_policy_rwsem_write(cpu);
969 kobject_uevent(&policy->kobj, KOBJ_ADD);
970 module_put(cpufreq_driver->owner);
971 dprintk("initialization complete\n");
972 cpufreq_debug_enable_ratelimit();
978 spin_lock_irqsave(&cpufreq_driver_lock, flags);
979 for_each_cpu(j, policy->cpus)
980 per_cpu(cpufreq_cpu_data, j) = NULL;
981 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
984 kobject_put(&policy->kobj);
985 wait_for_completion(&policy->kobj_unregister);
988 if (cpufreq_driver->exit)
989 cpufreq_driver->exit(policy);
992 unlock_policy_rwsem_write(cpu);
994 free_cpumask_var(policy->cpus);
998 module_put(cpufreq_driver->owner);
1000 cpufreq_debug_enable_ratelimit();
1006 * __cpufreq_remove_dev - remove a CPU device
1008 * Removes the cpufreq interface for a CPU device.
1009 * Caller should already have policy_rwsem in write mode for this CPU.
1010 * This routine frees the rwsem before returning.
1012 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1014 unsigned int cpu = sys_dev->id;
1015 unsigned long flags;
1016 struct cpufreq_policy *data;
1018 struct sys_device *cpu_sys_dev;
1022 cpufreq_debug_disable_ratelimit();
1023 dprintk("unregistering CPU %u\n", cpu);
1025 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1026 data = per_cpu(cpufreq_cpu_data, cpu);
1029 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1030 cpufreq_debug_enable_ratelimit();
1031 unlock_policy_rwsem_write(cpu);
1034 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1038 /* if this isn't the CPU which is the parent of the kobj, we
1039 * only need to unlink, put and exit
1041 if (unlikely(cpu != data->cpu)) {
1042 dprintk("removing link\n");
1043 cpumask_clear_cpu(cpu, data->cpus);
1044 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1045 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
1046 cpufreq_cpu_put(data);
1047 cpufreq_debug_enable_ratelimit();
1048 unlock_policy_rwsem_write(cpu);
1055 #ifdef CONFIG_HOTPLUG_CPU
1056 per_cpu(cpufreq_cpu_governor, cpu) = data->governor;
1059 /* if we have other CPUs still registered, we need to unlink them,
1060 * or else wait_for_completion below will lock up. Clean the
1061 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1062 * the sysfs links afterwards.
1064 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1065 for_each_cpu(j, data->cpus) {
1068 per_cpu(cpufreq_cpu_data, j) = NULL;
1072 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1074 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1075 for_each_cpu(j, data->cpus) {
1078 dprintk("removing link for cpu %u\n", j);
1079 #ifdef CONFIG_HOTPLUG_CPU
1080 per_cpu(cpufreq_cpu_governor, j) = data->governor;
1082 cpu_sys_dev = get_cpu_sysdev(j);
1083 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1084 cpufreq_cpu_put(data);
1088 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1091 if (cpufreq_driver->target)
1092 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1094 kobject_put(&data->kobj);
1096 /* we need to make sure that the underlying kobj is actually
1097 * not referenced anymore by anybody before we proceed with
1100 dprintk("waiting for dropping of refcount\n");
1101 wait_for_completion(&data->kobj_unregister);
1102 dprintk("wait complete\n");
1104 if (cpufreq_driver->exit)
1105 cpufreq_driver->exit(data);
1107 unlock_policy_rwsem_write(cpu);
1109 free_cpumask_var(data->related_cpus);
1110 free_cpumask_var(data->cpus);
1112 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1114 cpufreq_debug_enable_ratelimit();
1119 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1121 unsigned int cpu = sys_dev->id;
1124 if (cpu_is_offline(cpu))
1127 if (unlikely(lock_policy_rwsem_write(cpu)))
1130 retval = __cpufreq_remove_dev(sys_dev);
1135 static void handle_update(struct work_struct *work)
1137 struct cpufreq_policy *policy =
1138 container_of(work, struct cpufreq_policy, update);
1139 unsigned int cpu = policy->cpu;
1140 dprintk("handle_update for cpu %u called\n", cpu);
1141 cpufreq_update_policy(cpu);
1145 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1147 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1148 * @new_freq: CPU frequency the CPU actually runs at
1150 * We adjust to current frequency first, and need to clean up later.
1151 * So either call to cpufreq_update_policy() or schedule handle_update()).
1153 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1154 unsigned int new_freq)
1156 struct cpufreq_freqs freqs;
1158 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1159 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1162 freqs.old = old_freq;
1163 freqs.new = new_freq;
1164 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1165 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1170 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1173 * This is the last known freq, without actually getting it from the driver.
1174 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1176 unsigned int cpufreq_quick_get(unsigned int cpu)
1178 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1179 unsigned int ret_freq = 0;
1182 ret_freq = policy->cur;
1183 cpufreq_cpu_put(policy);
1188 EXPORT_SYMBOL(cpufreq_quick_get);
1191 static unsigned int __cpufreq_get(unsigned int cpu)
1193 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1194 unsigned int ret_freq = 0;
1196 if (!cpufreq_driver->get)
1199 ret_freq = cpufreq_driver->get(cpu);
1201 if (ret_freq && policy->cur &&
1202 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1203 /* verify no discrepancy between actual and
1204 saved value exists */
1205 if (unlikely(ret_freq != policy->cur)) {
1206 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1207 schedule_work(&policy->update);
1215 * cpufreq_get - get the current CPU frequency (in kHz)
1218 * Get the CPU current (static) CPU frequency
1220 unsigned int cpufreq_get(unsigned int cpu)
1222 unsigned int ret_freq = 0;
1223 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1228 if (unlikely(lock_policy_rwsem_read(cpu)))
1231 ret_freq = __cpufreq_get(cpu);
1233 unlock_policy_rwsem_read(cpu);
1236 cpufreq_cpu_put(policy);
1240 EXPORT_SYMBOL(cpufreq_get);
1244 * cpufreq_suspend - let the low level driver prepare for suspend
1247 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1249 int cpu = sysdev->id;
1251 unsigned int cur_freq = 0;
1252 struct cpufreq_policy *cpu_policy;
1254 dprintk("suspending cpu %u\n", cpu);
1256 if (!cpu_online(cpu))
1259 /* we may be lax here as interrupts are off. Nonetheless
1260 * we need to grab the correct cpu policy, as to check
1261 * whether we really run on this CPU.
1264 cpu_policy = cpufreq_cpu_get(cpu);
1268 /* only handle each CPU group once */
1269 if (unlikely(cpu_policy->cpu != cpu))
1272 if (cpufreq_driver->suspend) {
1273 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1275 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1276 "step on CPU %u\n", cpu_policy->cpu);
1281 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1284 if (cpufreq_driver->get)
1285 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1287 if (!cur_freq || !cpu_policy->cur) {
1288 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1289 "frequency is what timing core thinks it is.\n");
1293 if (unlikely(cur_freq != cpu_policy->cur)) {
1294 struct cpufreq_freqs freqs;
1296 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1297 dprintk("Warning: CPU frequency is %u, "
1298 "cpufreq assumed %u kHz.\n",
1299 cur_freq, cpu_policy->cur);
1302 freqs.old = cpu_policy->cur;
1303 freqs.new = cur_freq;
1305 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1306 CPUFREQ_SUSPENDCHANGE, &freqs);
1307 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1309 cpu_policy->cur = cur_freq;
1313 cpufreq_cpu_put(cpu_policy);
1318 * cpufreq_resume - restore proper CPU frequency handling after resume
1320 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1321 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1322 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1325 static int cpufreq_resume(struct sys_device *sysdev)
1327 int cpu = sysdev->id;
1329 struct cpufreq_policy *cpu_policy;
1331 dprintk("resuming cpu %u\n", cpu);
1333 if (!cpu_online(cpu))
1336 /* we may be lax here as interrupts are off. Nonetheless
1337 * we need to grab the correct cpu policy, as to check
1338 * whether we really run on this CPU.
1341 cpu_policy = cpufreq_cpu_get(cpu);
1345 /* only handle each CPU group once */
1346 if (unlikely(cpu_policy->cpu != cpu))
1349 if (cpufreq_driver->resume) {
1350 ret = cpufreq_driver->resume(cpu_policy);
1352 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1353 "step on CPU %u\n", cpu_policy->cpu);
1358 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1359 unsigned int cur_freq = 0;
1361 if (cpufreq_driver->get)
1362 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1364 if (!cur_freq || !cpu_policy->cur) {
1365 printk(KERN_ERR "cpufreq: resume failed to assert "
1366 "current frequency is what timing core "
1371 if (unlikely(cur_freq != cpu_policy->cur)) {
1372 struct cpufreq_freqs freqs;
1374 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1375 dprintk("Warning: CPU frequency "
1376 "is %u, cpufreq assumed %u kHz.\n",
1377 cur_freq, cpu_policy->cur);
1380 freqs.old = cpu_policy->cur;
1381 freqs.new = cur_freq;
1383 srcu_notifier_call_chain(
1384 &cpufreq_transition_notifier_list,
1385 CPUFREQ_RESUMECHANGE, &freqs);
1386 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1388 cpu_policy->cur = cur_freq;
1393 schedule_work(&cpu_policy->update);
1395 cpufreq_cpu_put(cpu_policy);
1399 static struct sysdev_driver cpufreq_sysdev_driver = {
1400 .add = cpufreq_add_dev,
1401 .remove = cpufreq_remove_dev,
1402 .suspend = cpufreq_suspend,
1403 .resume = cpufreq_resume,
1407 /*********************************************************************
1408 * NOTIFIER LISTS INTERFACE *
1409 *********************************************************************/
1412 * cpufreq_register_notifier - register a driver with cpufreq
1413 * @nb: notifier function to register
1414 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1416 * Add a driver to one of two lists: either a list of drivers that
1417 * are notified about clock rate changes (once before and once after
1418 * the transition), or a list of drivers that are notified about
1419 * changes in cpufreq policy.
1421 * This function may sleep, and has the same return conditions as
1422 * blocking_notifier_chain_register.
1424 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1428 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1431 case CPUFREQ_TRANSITION_NOTIFIER:
1432 ret = srcu_notifier_chain_register(
1433 &cpufreq_transition_notifier_list, nb);
1435 case CPUFREQ_POLICY_NOTIFIER:
1436 ret = blocking_notifier_chain_register(
1437 &cpufreq_policy_notifier_list, nb);
1445 EXPORT_SYMBOL(cpufreq_register_notifier);
1449 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1450 * @nb: notifier block to be unregistered
1451 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1453 * Remove a driver from the CPU frequency notifier list.
1455 * This function may sleep, and has the same return conditions as
1456 * blocking_notifier_chain_unregister.
1458 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1463 case CPUFREQ_TRANSITION_NOTIFIER:
1464 ret = srcu_notifier_chain_unregister(
1465 &cpufreq_transition_notifier_list, nb);
1467 case CPUFREQ_POLICY_NOTIFIER:
1468 ret = blocking_notifier_chain_unregister(
1469 &cpufreq_policy_notifier_list, nb);
1477 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1480 /*********************************************************************
1482 *********************************************************************/
1485 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1486 unsigned int target_freq,
1487 unsigned int relation)
1489 int retval = -EINVAL;
1491 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1492 target_freq, relation);
1493 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1494 retval = cpufreq_driver->target(policy, target_freq, relation);
1498 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1500 int cpufreq_driver_target(struct cpufreq_policy *policy,
1501 unsigned int target_freq,
1502 unsigned int relation)
1506 policy = cpufreq_cpu_get(policy->cpu);
1510 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1513 ret = __cpufreq_driver_target(policy, target_freq, relation);
1515 unlock_policy_rwsem_write(policy->cpu);
1518 cpufreq_cpu_put(policy);
1522 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1524 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1528 policy = cpufreq_cpu_get(policy->cpu);
1532 if (cpu_online(cpu) && cpufreq_driver->getavg)
1533 ret = cpufreq_driver->getavg(policy, cpu);
1535 cpufreq_cpu_put(policy);
1538 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1541 * when "event" is CPUFREQ_GOV_LIMITS
1544 static int __cpufreq_governor(struct cpufreq_policy *policy,
1549 /* Only must be defined when default governor is known to have latency
1550 restrictions, like e.g. conservative or ondemand.
1551 That this is the case is already ensured in Kconfig
1553 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1554 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1556 struct cpufreq_governor *gov = NULL;
1559 if (policy->governor->max_transition_latency &&
1560 policy->cpuinfo.transition_latency >
1561 policy->governor->max_transition_latency) {
1565 printk(KERN_WARNING "%s governor failed, too long"
1566 " transition latency of HW, fallback"
1567 " to %s governor\n",
1568 policy->governor->name,
1570 policy->governor = gov;
1574 if (!try_module_get(policy->governor->owner))
1577 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1578 policy->cpu, event);
1579 ret = policy->governor->governor(policy, event);
1581 /* we keep one module reference alive for
1582 each CPU governed by this CPU */
1583 if ((event != CPUFREQ_GOV_START) || ret)
1584 module_put(policy->governor->owner);
1585 if ((event == CPUFREQ_GOV_STOP) && !ret)
1586 module_put(policy->governor->owner);
1592 int cpufreq_register_governor(struct cpufreq_governor *governor)
1599 mutex_lock(&cpufreq_governor_mutex);
1602 if (__find_governor(governor->name) == NULL) {
1604 list_add(&governor->governor_list, &cpufreq_governor_list);
1607 mutex_unlock(&cpufreq_governor_mutex);
1610 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1613 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1618 mutex_lock(&cpufreq_governor_mutex);
1619 list_del(&governor->governor_list);
1620 mutex_unlock(&cpufreq_governor_mutex);
1623 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1627 /*********************************************************************
1628 * POLICY INTERFACE *
1629 *********************************************************************/
1632 * cpufreq_get_policy - get the current cpufreq_policy
1633 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1636 * Reads the current cpufreq policy.
1638 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1640 struct cpufreq_policy *cpu_policy;
1644 cpu_policy = cpufreq_cpu_get(cpu);
1648 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1650 cpufreq_cpu_put(cpu_policy);
1653 EXPORT_SYMBOL(cpufreq_get_policy);
1657 * data : current policy.
1658 * policy : policy to be set.
1660 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1661 struct cpufreq_policy *policy)
1665 cpufreq_debug_disable_ratelimit();
1666 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1667 policy->min, policy->max);
1669 memcpy(&policy->cpuinfo, &data->cpuinfo,
1670 sizeof(struct cpufreq_cpuinfo));
1672 if (policy->min > data->max || policy->max < data->min) {
1677 /* verify the cpu speed can be set within this limit */
1678 ret = cpufreq_driver->verify(policy);
1682 /* adjust if necessary - all reasons */
1683 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1684 CPUFREQ_ADJUST, policy);
1686 /* adjust if necessary - hardware incompatibility*/
1687 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1688 CPUFREQ_INCOMPATIBLE, policy);
1690 /* verify the cpu speed can be set within this limit,
1691 which might be different to the first one */
1692 ret = cpufreq_driver->verify(policy);
1696 /* notification of the new policy */
1697 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1698 CPUFREQ_NOTIFY, policy);
1700 data->min = policy->min;
1701 data->max = policy->max;
1703 dprintk("new min and max freqs are %u - %u kHz\n",
1704 data->min, data->max);
1706 if (cpufreq_driver->setpolicy) {
1707 data->policy = policy->policy;
1708 dprintk("setting range\n");
1709 ret = cpufreq_driver->setpolicy(policy);
1711 if (policy->governor != data->governor) {
1712 /* save old, working values */
1713 struct cpufreq_governor *old_gov = data->governor;
1715 dprintk("governor switch\n");
1717 /* end old governor */
1719 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1721 /* start new governor */
1722 data->governor = policy->governor;
1723 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1724 /* new governor failed, so re-start old one */
1725 dprintk("starting governor %s failed\n",
1726 data->governor->name);
1728 data->governor = old_gov;
1729 __cpufreq_governor(data,
1735 /* might be a policy change, too, so fall through */
1737 dprintk("governor: change or update limits\n");
1738 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1742 cpufreq_debug_enable_ratelimit();
1747 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1748 * @cpu: CPU which shall be re-evaluated
1750 * Usefull for policy notifiers which have different necessities
1751 * at different times.
1753 int cpufreq_update_policy(unsigned int cpu)
1755 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1756 struct cpufreq_policy policy;
1764 if (unlikely(lock_policy_rwsem_write(cpu))) {
1769 dprintk("updating policy for CPU %u\n", cpu);
1770 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1771 policy.min = data->user_policy.min;
1772 policy.max = data->user_policy.max;
1773 policy.policy = data->user_policy.policy;
1774 policy.governor = data->user_policy.governor;
1776 /* BIOS might change freq behind our back
1777 -> ask driver for current freq and notify governors about a change */
1778 if (cpufreq_driver->get) {
1779 policy.cur = cpufreq_driver->get(cpu);
1781 dprintk("Driver did not initialize current freq");
1782 data->cur = policy.cur;
1784 if (data->cur != policy.cur)
1785 cpufreq_out_of_sync(cpu, data->cur,
1790 ret = __cpufreq_set_policy(data, &policy);
1792 unlock_policy_rwsem_write(cpu);
1795 cpufreq_cpu_put(data);
1799 EXPORT_SYMBOL(cpufreq_update_policy);
1801 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1802 unsigned long action, void *hcpu)
1804 unsigned int cpu = (unsigned long)hcpu;
1805 struct sys_device *sys_dev;
1807 sys_dev = get_cpu_sysdev(cpu);
1811 case CPU_ONLINE_FROZEN:
1812 cpufreq_add_dev(sys_dev);
1814 case CPU_DOWN_PREPARE:
1815 case CPU_DOWN_PREPARE_FROZEN:
1816 if (unlikely(lock_policy_rwsem_write(cpu)))
1819 __cpufreq_remove_dev(sys_dev);
1821 case CPU_DOWN_FAILED:
1822 case CPU_DOWN_FAILED_FROZEN:
1823 cpufreq_add_dev(sys_dev);
1830 static struct notifier_block __refdata cpufreq_cpu_notifier =
1832 .notifier_call = cpufreq_cpu_callback,
1835 /*********************************************************************
1836 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1837 *********************************************************************/
1840 * cpufreq_register_driver - register a CPU Frequency driver
1841 * @driver_data: A struct cpufreq_driver containing the values#
1842 * submitted by the CPU Frequency driver.
1844 * Registers a CPU Frequency driver to this core code. This code
1845 * returns zero on success, -EBUSY when another driver got here first
1846 * (and isn't unregistered in the meantime).
1849 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1851 unsigned long flags;
1854 if (!driver_data || !driver_data->verify || !driver_data->init ||
1855 ((!driver_data->setpolicy) && (!driver_data->target)))
1858 dprintk("trying to register driver %s\n", driver_data->name);
1860 if (driver_data->setpolicy)
1861 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1863 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1864 if (cpufreq_driver) {
1865 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1868 cpufreq_driver = driver_data;
1869 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1871 ret = sysdev_driver_register(&cpu_sysdev_class,
1872 &cpufreq_sysdev_driver);
1874 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1878 /* check for at least one working CPU */
1879 for (i = 0; i < nr_cpu_ids; i++)
1880 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1885 /* if all ->init() calls failed, unregister */
1887 dprintk("no CPU initialized for driver %s\n",
1889 sysdev_driver_unregister(&cpu_sysdev_class,
1890 &cpufreq_sysdev_driver);
1892 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1893 cpufreq_driver = NULL;
1894 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1899 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1900 dprintk("driver %s up and running\n", driver_data->name);
1901 cpufreq_debug_enable_ratelimit();
1906 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1910 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1912 * Unregister the current CPUFreq driver. Only call this if you have
1913 * the right to do so, i.e. if you have succeeded in initialising before!
1914 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1915 * currently not initialised.
1917 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1919 unsigned long flags;
1921 cpufreq_debug_disable_ratelimit();
1923 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1924 cpufreq_debug_enable_ratelimit();
1928 dprintk("unregistering driver %s\n", driver->name);
1930 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1931 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1933 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1934 cpufreq_driver = NULL;
1935 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1939 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1941 static int __init cpufreq_core_init(void)
1945 for_each_possible_cpu(cpu) {
1946 per_cpu(policy_cpu, cpu) = -1;
1947 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1952 core_initcall(cpufreq_core_init);