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.
861 * cpufreq_cpu_put is called when the device is removed
862 * in __cpufreq_remove_dev()
864 managed_policy = cpufreq_cpu_get(j);
865 if (unlikely(managed_policy)) {
867 /* Set proper policy_cpu */
868 unlock_policy_rwsem_write(cpu);
869 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
871 if (lock_policy_rwsem_write(cpu) < 0) {
872 /* Should not go through policy unlock path */
873 if (cpufreq_driver->exit)
874 cpufreq_driver->exit(policy);
876 cpufreq_cpu_put(managed_policy);
877 goto err_free_cpumask;
880 spin_lock_irqsave(&cpufreq_driver_lock, flags);
881 cpumask_copy(managed_policy->cpus, policy->cpus);
882 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
883 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
885 dprintk("CPU already managed, adding link\n");
886 ret = sysfs_create_link(&sys_dev->kobj,
887 &managed_policy->kobj,
890 cpufreq_cpu_put(managed_policy);
892 * Success. We only needed to be added to the mask.
893 * Call driver->exit() because only the cpu parent of
894 * the kobj needed to call init().
896 goto out_driver_exit; /* call driver->exit() */
900 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
902 /* prepare interface data */
903 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
906 goto out_driver_exit;
908 /* set up files for this cpu device */
909 drv_attr = cpufreq_driver->attr;
910 while ((drv_attr) && (*drv_attr)) {
911 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
913 goto err_out_kobj_put;
916 if (cpufreq_driver->get) {
917 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
919 goto err_out_kobj_put;
921 if (cpufreq_driver->target) {
922 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
924 goto err_out_kobj_put;
927 spin_lock_irqsave(&cpufreq_driver_lock, flags);
928 for_each_cpu(j, policy->cpus) {
931 per_cpu(cpufreq_cpu_data, j) = policy;
932 per_cpu(policy_cpu, j) = policy->cpu;
934 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
936 /* symlink affected CPUs */
937 for_each_cpu(j, policy->cpus) {
938 struct cpufreq_policy *managed_policy;
945 dprintk("CPU %u already managed, adding link\n", j);
946 managed_policy = cpufreq_cpu_get(cpu);
947 cpu_sys_dev = get_cpu_sysdev(j);
948 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
951 cpufreq_cpu_put(managed_policy);
952 goto err_out_unregister;
956 policy->governor = NULL; /* to assure that the starting sequence is
957 * run in cpufreq_set_policy */
959 /* set default policy */
960 ret = __cpufreq_set_policy(policy, &new_policy);
961 policy->user_policy.policy = policy->policy;
962 policy->user_policy.governor = policy->governor;
965 dprintk("setting policy failed\n");
966 goto err_out_unregister;
969 unlock_policy_rwsem_write(cpu);
971 kobject_uevent(&policy->kobj, KOBJ_ADD);
972 module_put(cpufreq_driver->owner);
973 dprintk("initialization complete\n");
974 cpufreq_debug_enable_ratelimit();
980 spin_lock_irqsave(&cpufreq_driver_lock, flags);
981 for_each_cpu(j, policy->cpus)
982 per_cpu(cpufreq_cpu_data, j) = NULL;
983 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
986 kobject_put(&policy->kobj);
987 wait_for_completion(&policy->kobj_unregister);
990 if (cpufreq_driver->exit)
991 cpufreq_driver->exit(policy);
994 unlock_policy_rwsem_write(cpu);
996 free_cpumask_var(policy->cpus);
1000 module_put(cpufreq_driver->owner);
1002 cpufreq_debug_enable_ratelimit();
1008 * __cpufreq_remove_dev - remove a CPU device
1010 * Removes the cpufreq interface for a CPU device.
1011 * Caller should already have policy_rwsem in write mode for this CPU.
1012 * This routine frees the rwsem before returning.
1014 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1016 unsigned int cpu = sys_dev->id;
1017 unsigned long flags;
1018 struct cpufreq_policy *data;
1020 struct sys_device *cpu_sys_dev;
1024 cpufreq_debug_disable_ratelimit();
1025 dprintk("unregistering CPU %u\n", cpu);
1027 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1028 data = per_cpu(cpufreq_cpu_data, cpu);
1031 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1032 cpufreq_debug_enable_ratelimit();
1033 unlock_policy_rwsem_write(cpu);
1036 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1040 /* if this isn't the CPU which is the parent of the kobj, we
1041 * only need to unlink, put and exit
1043 if (unlikely(cpu != data->cpu)) {
1044 dprintk("removing link\n");
1045 cpumask_clear_cpu(cpu, data->cpus);
1046 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1047 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
1048 cpufreq_cpu_put(data);
1049 cpufreq_debug_enable_ratelimit();
1050 unlock_policy_rwsem_write(cpu);
1057 #ifdef CONFIG_HOTPLUG_CPU
1058 per_cpu(cpufreq_cpu_governor, cpu) = data->governor;
1061 /* if we have other CPUs still registered, we need to unlink them,
1062 * or else wait_for_completion below will lock up. Clean the
1063 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1064 * the sysfs links afterwards.
1066 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1067 for_each_cpu(j, data->cpus) {
1070 per_cpu(cpufreq_cpu_data, j) = NULL;
1074 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1076 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1077 for_each_cpu(j, data->cpus) {
1080 dprintk("removing link for cpu %u\n", j);
1081 #ifdef CONFIG_HOTPLUG_CPU
1082 per_cpu(cpufreq_cpu_governor, j) = data->governor;
1084 cpu_sys_dev = get_cpu_sysdev(j);
1085 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1086 cpufreq_cpu_put(data);
1090 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1093 if (cpufreq_driver->target)
1094 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1096 kobject_put(&data->kobj);
1098 /* we need to make sure that the underlying kobj is actually
1099 * not referenced anymore by anybody before we proceed with
1102 dprintk("waiting for dropping of refcount\n");
1103 wait_for_completion(&data->kobj_unregister);
1104 dprintk("wait complete\n");
1106 if (cpufreq_driver->exit)
1107 cpufreq_driver->exit(data);
1109 unlock_policy_rwsem_write(cpu);
1111 free_cpumask_var(data->related_cpus);
1112 free_cpumask_var(data->cpus);
1114 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1116 cpufreq_debug_enable_ratelimit();
1121 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1123 unsigned int cpu = sys_dev->id;
1126 if (cpu_is_offline(cpu))
1129 if (unlikely(lock_policy_rwsem_write(cpu)))
1132 retval = __cpufreq_remove_dev(sys_dev);
1137 static void handle_update(struct work_struct *work)
1139 struct cpufreq_policy *policy =
1140 container_of(work, struct cpufreq_policy, update);
1141 unsigned int cpu = policy->cpu;
1142 dprintk("handle_update for cpu %u called\n", cpu);
1143 cpufreq_update_policy(cpu);
1147 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1149 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1150 * @new_freq: CPU frequency the CPU actually runs at
1152 * We adjust to current frequency first, and need to clean up later.
1153 * So either call to cpufreq_update_policy() or schedule handle_update()).
1155 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1156 unsigned int new_freq)
1158 struct cpufreq_freqs freqs;
1160 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1161 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1164 freqs.old = old_freq;
1165 freqs.new = new_freq;
1166 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1167 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1172 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1175 * This is the last known freq, without actually getting it from the driver.
1176 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1178 unsigned int cpufreq_quick_get(unsigned int cpu)
1180 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1181 unsigned int ret_freq = 0;
1184 ret_freq = policy->cur;
1185 cpufreq_cpu_put(policy);
1190 EXPORT_SYMBOL(cpufreq_quick_get);
1193 static unsigned int __cpufreq_get(unsigned int cpu)
1195 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1196 unsigned int ret_freq = 0;
1198 if (!cpufreq_driver->get)
1201 ret_freq = cpufreq_driver->get(cpu);
1203 if (ret_freq && policy->cur &&
1204 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1205 /* verify no discrepancy between actual and
1206 saved value exists */
1207 if (unlikely(ret_freq != policy->cur)) {
1208 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1209 schedule_work(&policy->update);
1217 * cpufreq_get - get the current CPU frequency (in kHz)
1220 * Get the CPU current (static) CPU frequency
1222 unsigned int cpufreq_get(unsigned int cpu)
1224 unsigned int ret_freq = 0;
1225 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1230 if (unlikely(lock_policy_rwsem_read(cpu)))
1233 ret_freq = __cpufreq_get(cpu);
1235 unlock_policy_rwsem_read(cpu);
1238 cpufreq_cpu_put(policy);
1242 EXPORT_SYMBOL(cpufreq_get);
1246 * cpufreq_suspend - let the low level driver prepare for suspend
1249 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1254 int cpu = sysdev->id;
1255 unsigned int cur_freq = 0;
1256 struct cpufreq_policy *cpu_policy;
1258 dprintk("suspending cpu %u\n", cpu);
1261 * This whole bogosity is here because Powerbooks are made of fail.
1262 * No sane platform should need any of the code below to be run.
1263 * (it's entirely the wrong thing to do, as driver->get may
1264 * reenable interrupts on some architectures).
1267 if (!cpu_online(cpu))
1270 /* we may be lax here as interrupts are off. Nonetheless
1271 * we need to grab the correct cpu policy, as to check
1272 * whether we really run on this CPU.
1275 cpu_policy = cpufreq_cpu_get(cpu);
1279 /* only handle each CPU group once */
1280 if (unlikely(cpu_policy->cpu != cpu))
1283 if (cpufreq_driver->suspend) {
1284 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1286 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1287 "step on CPU %u\n", cpu_policy->cpu);
1292 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1295 if (cpufreq_driver->get)
1296 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1298 if (!cur_freq || !cpu_policy->cur) {
1299 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1300 "frequency is what timing core thinks it is.\n");
1304 if (unlikely(cur_freq != cpu_policy->cur)) {
1305 struct cpufreq_freqs freqs;
1307 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1308 dprintk("Warning: CPU frequency is %u, "
1309 "cpufreq assumed %u kHz.\n",
1310 cur_freq, cpu_policy->cur);
1313 freqs.old = cpu_policy->cur;
1314 freqs.new = cur_freq;
1316 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1317 CPUFREQ_SUSPENDCHANGE, &freqs);
1318 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1320 cpu_policy->cur = cur_freq;
1324 cpufreq_cpu_put(cpu_policy);
1325 #endif /* __powerpc__ */
1330 * cpufreq_resume - restore proper CPU frequency handling after resume
1332 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1333 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1334 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1337 static int cpufreq_resume(struct sys_device *sysdev)
1342 int cpu = sysdev->id;
1343 struct cpufreq_policy *cpu_policy;
1345 dprintk("resuming cpu %u\n", cpu);
1347 /* As with the ->suspend method, all the code below is
1348 * only necessary because Powerbooks suck.
1349 * See commit 42d4dc3f4e1e for jokes. */
1351 if (!cpu_online(cpu))
1354 /* we may be lax here as interrupts are off. Nonetheless
1355 * we need to grab the correct cpu policy, as to check
1356 * whether we really run on this CPU.
1359 cpu_policy = cpufreq_cpu_get(cpu);
1363 /* only handle each CPU group once */
1364 if (unlikely(cpu_policy->cpu != cpu))
1367 if (cpufreq_driver->resume) {
1368 ret = cpufreq_driver->resume(cpu_policy);
1370 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1371 "step on CPU %u\n", cpu_policy->cpu);
1376 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1377 unsigned int cur_freq = 0;
1379 if (cpufreq_driver->get)
1380 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1382 if (!cur_freq || !cpu_policy->cur) {
1383 printk(KERN_ERR "cpufreq: resume failed to assert "
1384 "current frequency is what timing core "
1389 if (unlikely(cur_freq != cpu_policy->cur)) {
1390 struct cpufreq_freqs freqs;
1392 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1393 dprintk("Warning: CPU frequency "
1394 "is %u, cpufreq assumed %u kHz.\n",
1395 cur_freq, cpu_policy->cur);
1398 freqs.old = cpu_policy->cur;
1399 freqs.new = cur_freq;
1401 srcu_notifier_call_chain(
1402 &cpufreq_transition_notifier_list,
1403 CPUFREQ_RESUMECHANGE, &freqs);
1404 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1406 cpu_policy->cur = cur_freq;
1411 schedule_work(&cpu_policy->update);
1413 cpufreq_cpu_put(cpu_policy);
1414 #endif /* __powerpc__ */
1418 static struct sysdev_driver cpufreq_sysdev_driver = {
1419 .add = cpufreq_add_dev,
1420 .remove = cpufreq_remove_dev,
1421 .suspend = cpufreq_suspend,
1422 .resume = cpufreq_resume,
1426 /*********************************************************************
1427 * NOTIFIER LISTS INTERFACE *
1428 *********************************************************************/
1431 * cpufreq_register_notifier - register a driver with cpufreq
1432 * @nb: notifier function to register
1433 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1435 * Add a driver to one of two lists: either a list of drivers that
1436 * are notified about clock rate changes (once before and once after
1437 * the transition), or a list of drivers that are notified about
1438 * changes in cpufreq policy.
1440 * This function may sleep, and has the same return conditions as
1441 * blocking_notifier_chain_register.
1443 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1447 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1450 case CPUFREQ_TRANSITION_NOTIFIER:
1451 ret = srcu_notifier_chain_register(
1452 &cpufreq_transition_notifier_list, nb);
1454 case CPUFREQ_POLICY_NOTIFIER:
1455 ret = blocking_notifier_chain_register(
1456 &cpufreq_policy_notifier_list, nb);
1464 EXPORT_SYMBOL(cpufreq_register_notifier);
1468 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1469 * @nb: notifier block to be unregistered
1470 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1472 * Remove a driver from the CPU frequency notifier list.
1474 * This function may sleep, and has the same return conditions as
1475 * blocking_notifier_chain_unregister.
1477 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1482 case CPUFREQ_TRANSITION_NOTIFIER:
1483 ret = srcu_notifier_chain_unregister(
1484 &cpufreq_transition_notifier_list, nb);
1486 case CPUFREQ_POLICY_NOTIFIER:
1487 ret = blocking_notifier_chain_unregister(
1488 &cpufreq_policy_notifier_list, nb);
1496 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1499 /*********************************************************************
1501 *********************************************************************/
1504 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1505 unsigned int target_freq,
1506 unsigned int relation)
1508 int retval = -EINVAL;
1510 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1511 target_freq, relation);
1512 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1513 retval = cpufreq_driver->target(policy, target_freq, relation);
1517 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1519 int cpufreq_driver_target(struct cpufreq_policy *policy,
1520 unsigned int target_freq,
1521 unsigned int relation)
1525 policy = cpufreq_cpu_get(policy->cpu);
1529 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1532 ret = __cpufreq_driver_target(policy, target_freq, relation);
1534 unlock_policy_rwsem_write(policy->cpu);
1537 cpufreq_cpu_put(policy);
1541 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1543 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1547 policy = cpufreq_cpu_get(policy->cpu);
1551 if (cpu_online(cpu) && cpufreq_driver->getavg)
1552 ret = cpufreq_driver->getavg(policy, cpu);
1554 cpufreq_cpu_put(policy);
1557 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1560 * when "event" is CPUFREQ_GOV_LIMITS
1563 static int __cpufreq_governor(struct cpufreq_policy *policy,
1568 /* Only must be defined when default governor is known to have latency
1569 restrictions, like e.g. conservative or ondemand.
1570 That this is the case is already ensured in Kconfig
1572 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1573 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1575 struct cpufreq_governor *gov = NULL;
1578 if (policy->governor->max_transition_latency &&
1579 policy->cpuinfo.transition_latency >
1580 policy->governor->max_transition_latency) {
1584 printk(KERN_WARNING "%s governor failed, too long"
1585 " transition latency of HW, fallback"
1586 " to %s governor\n",
1587 policy->governor->name,
1589 policy->governor = gov;
1593 if (!try_module_get(policy->governor->owner))
1596 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1597 policy->cpu, event);
1598 ret = policy->governor->governor(policy, event);
1600 /* we keep one module reference alive for
1601 each CPU governed by this CPU */
1602 if ((event != CPUFREQ_GOV_START) || ret)
1603 module_put(policy->governor->owner);
1604 if ((event == CPUFREQ_GOV_STOP) && !ret)
1605 module_put(policy->governor->owner);
1611 int cpufreq_register_governor(struct cpufreq_governor *governor)
1618 mutex_lock(&cpufreq_governor_mutex);
1621 if (__find_governor(governor->name) == NULL) {
1623 list_add(&governor->governor_list, &cpufreq_governor_list);
1626 mutex_unlock(&cpufreq_governor_mutex);
1629 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1632 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1637 mutex_lock(&cpufreq_governor_mutex);
1638 list_del(&governor->governor_list);
1639 mutex_unlock(&cpufreq_governor_mutex);
1642 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1646 /*********************************************************************
1647 * POLICY INTERFACE *
1648 *********************************************************************/
1651 * cpufreq_get_policy - get the current cpufreq_policy
1652 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1655 * Reads the current cpufreq policy.
1657 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1659 struct cpufreq_policy *cpu_policy;
1663 cpu_policy = cpufreq_cpu_get(cpu);
1667 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1669 cpufreq_cpu_put(cpu_policy);
1672 EXPORT_SYMBOL(cpufreq_get_policy);
1676 * data : current policy.
1677 * policy : policy to be set.
1679 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1680 struct cpufreq_policy *policy)
1684 cpufreq_debug_disable_ratelimit();
1685 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1686 policy->min, policy->max);
1688 memcpy(&policy->cpuinfo, &data->cpuinfo,
1689 sizeof(struct cpufreq_cpuinfo));
1691 if (policy->min > data->max || policy->max < data->min) {
1696 /* verify the cpu speed can be set within this limit */
1697 ret = cpufreq_driver->verify(policy);
1701 /* adjust if necessary - all reasons */
1702 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1703 CPUFREQ_ADJUST, policy);
1705 /* adjust if necessary - hardware incompatibility*/
1706 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1707 CPUFREQ_INCOMPATIBLE, policy);
1709 /* verify the cpu speed can be set within this limit,
1710 which might be different to the first one */
1711 ret = cpufreq_driver->verify(policy);
1715 /* notification of the new policy */
1716 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1717 CPUFREQ_NOTIFY, policy);
1719 data->min = policy->min;
1720 data->max = policy->max;
1722 dprintk("new min and max freqs are %u - %u kHz\n",
1723 data->min, data->max);
1725 if (cpufreq_driver->setpolicy) {
1726 data->policy = policy->policy;
1727 dprintk("setting range\n");
1728 ret = cpufreq_driver->setpolicy(policy);
1730 if (policy->governor != data->governor) {
1731 /* save old, working values */
1732 struct cpufreq_governor *old_gov = data->governor;
1734 dprintk("governor switch\n");
1736 /* end old governor */
1738 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1740 /* start new governor */
1741 data->governor = policy->governor;
1742 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1743 /* new governor failed, so re-start old one */
1744 dprintk("starting governor %s failed\n",
1745 data->governor->name);
1747 data->governor = old_gov;
1748 __cpufreq_governor(data,
1754 /* might be a policy change, too, so fall through */
1756 dprintk("governor: change or update limits\n");
1757 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1761 cpufreq_debug_enable_ratelimit();
1766 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1767 * @cpu: CPU which shall be re-evaluated
1769 * Usefull for policy notifiers which have different necessities
1770 * at different times.
1772 int cpufreq_update_policy(unsigned int cpu)
1774 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1775 struct cpufreq_policy policy;
1783 if (unlikely(lock_policy_rwsem_write(cpu))) {
1788 dprintk("updating policy for CPU %u\n", cpu);
1789 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1790 policy.min = data->user_policy.min;
1791 policy.max = data->user_policy.max;
1792 policy.policy = data->user_policy.policy;
1793 policy.governor = data->user_policy.governor;
1795 /* BIOS might change freq behind our back
1796 -> ask driver for current freq and notify governors about a change */
1797 if (cpufreq_driver->get) {
1798 policy.cur = cpufreq_driver->get(cpu);
1800 dprintk("Driver did not initialize current freq");
1801 data->cur = policy.cur;
1803 if (data->cur != policy.cur)
1804 cpufreq_out_of_sync(cpu, data->cur,
1809 ret = __cpufreq_set_policy(data, &policy);
1811 unlock_policy_rwsem_write(cpu);
1814 cpufreq_cpu_put(data);
1818 EXPORT_SYMBOL(cpufreq_update_policy);
1820 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1821 unsigned long action, void *hcpu)
1823 unsigned int cpu = (unsigned long)hcpu;
1824 struct sys_device *sys_dev;
1826 sys_dev = get_cpu_sysdev(cpu);
1830 case CPU_ONLINE_FROZEN:
1831 cpufreq_add_dev(sys_dev);
1833 case CPU_DOWN_PREPARE:
1834 case CPU_DOWN_PREPARE_FROZEN:
1835 if (unlikely(lock_policy_rwsem_write(cpu)))
1838 __cpufreq_remove_dev(sys_dev);
1840 case CPU_DOWN_FAILED:
1841 case CPU_DOWN_FAILED_FROZEN:
1842 cpufreq_add_dev(sys_dev);
1849 static struct notifier_block __refdata cpufreq_cpu_notifier =
1851 .notifier_call = cpufreq_cpu_callback,
1854 /*********************************************************************
1855 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1856 *********************************************************************/
1859 * cpufreq_register_driver - register a CPU Frequency driver
1860 * @driver_data: A struct cpufreq_driver containing the values#
1861 * submitted by the CPU Frequency driver.
1863 * Registers a CPU Frequency driver to this core code. This code
1864 * returns zero on success, -EBUSY when another driver got here first
1865 * (and isn't unregistered in the meantime).
1868 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1870 unsigned long flags;
1873 if (!driver_data || !driver_data->verify || !driver_data->init ||
1874 ((!driver_data->setpolicy) && (!driver_data->target)))
1877 dprintk("trying to register driver %s\n", driver_data->name);
1879 if (driver_data->setpolicy)
1880 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1882 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1883 if (cpufreq_driver) {
1884 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1887 cpufreq_driver = driver_data;
1888 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1890 ret = sysdev_driver_register(&cpu_sysdev_class,
1891 &cpufreq_sysdev_driver);
1893 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1897 /* check for at least one working CPU */
1898 for (i = 0; i < nr_cpu_ids; i++)
1899 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1904 /* if all ->init() calls failed, unregister */
1906 dprintk("no CPU initialized for driver %s\n",
1908 sysdev_driver_unregister(&cpu_sysdev_class,
1909 &cpufreq_sysdev_driver);
1911 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1912 cpufreq_driver = NULL;
1913 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1918 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1919 dprintk("driver %s up and running\n", driver_data->name);
1920 cpufreq_debug_enable_ratelimit();
1925 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1929 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1931 * Unregister the current CPUFreq driver. Only call this if you have
1932 * the right to do so, i.e. if you have succeeded in initialising before!
1933 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1934 * currently not initialised.
1936 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1938 unsigned long flags;
1940 cpufreq_debug_disable_ratelimit();
1942 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1943 cpufreq_debug_enable_ratelimit();
1947 dprintk("unregistering driver %s\n", driver->name);
1949 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1950 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1952 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1953 cpufreq_driver = NULL;
1954 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1958 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1960 static int __init cpufreq_core_init(void)
1964 for_each_possible_cpu(cpu) {
1965 per_cpu(policy_cpu, cpu) = -1;
1966 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1971 core_initcall(cpufreq_core_init);