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
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
16 #include <linux/config.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/notifier.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/interrupt.h>
24 #include <linux/spinlock.h>
25 #include <linux/device.h>
26 #include <linux/slab.h>
27 #include <linux/cpu.h>
28 #include <linux/completion.h>
29 #include <linux/mutex.h>
31 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
34 * The "cpufreq driver" - the arch- or hardware-dependend low
35 * level driver of CPUFreq support, and its spinlock. This lock
36 * also protects the cpufreq_cpu_data array.
38 static struct cpufreq_driver *cpufreq_driver;
39 static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
40 static DEFINE_SPINLOCK(cpufreq_driver_lock);
42 /* internal prototypes */
43 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
44 static void handle_update(void *data);
47 * Two notifier lists: the "policy" list is involved in the
48 * validation process for a new CPU frequency policy; the
49 * "transition" list for kernel code that needs to handle
50 * changes to devices when the CPU clock speed changes.
51 * The mutex locks both lists.
53 static struct notifier_block *cpufreq_policy_notifier_list;
54 static struct notifier_block *cpufreq_transition_notifier_list;
55 static DECLARE_RWSEM (cpufreq_notifier_rwsem);
58 static LIST_HEAD(cpufreq_governor_list);
59 static DEFINE_MUTEX (cpufreq_governor_mutex);
61 struct cpufreq_policy * cpufreq_cpu_get(unsigned int cpu)
63 struct cpufreq_policy *data;
69 /* get the cpufreq driver */
70 spin_lock_irqsave(&cpufreq_driver_lock, flags);
75 if (!try_module_get(cpufreq_driver->owner))
80 data = cpufreq_cpu_data[cpu];
83 goto err_out_put_module;
85 if (!kobject_get(&data->kobj))
86 goto err_out_put_module;
89 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
94 module_put(cpufreq_driver->owner);
96 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
100 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
102 void cpufreq_cpu_put(struct cpufreq_policy *data)
104 kobject_put(&data->kobj);
105 module_put(cpufreq_driver->owner);
107 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
110 /*********************************************************************
111 * UNIFIED DEBUG HELPERS *
112 *********************************************************************/
113 #ifdef CONFIG_CPU_FREQ_DEBUG
115 /* what part(s) of the CPUfreq subsystem are debugged? */
116 static unsigned int debug;
118 /* is the debug output ratelimit'ed using printk_ratelimit? User can
119 * set or modify this value.
121 static unsigned int debug_ratelimit = 1;
123 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
124 * loading of a cpufreq driver, temporarily disabled when a new policy
125 * is set, and disabled upon cpufreq driver removal
127 static unsigned int disable_ratelimit = 1;
128 static DEFINE_SPINLOCK(disable_ratelimit_lock);
130 static void cpufreq_debug_enable_ratelimit(void)
134 spin_lock_irqsave(&disable_ratelimit_lock, flags);
135 if (disable_ratelimit)
137 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
140 static void cpufreq_debug_disable_ratelimit(void)
144 spin_lock_irqsave(&disable_ratelimit_lock, flags);
146 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
149 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
158 spin_lock_irqsave(&disable_ratelimit_lock, flags);
159 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
160 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
163 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
165 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
168 len += vsnprintf(&s[len], (256 - len), fmt, args);
176 EXPORT_SYMBOL(cpufreq_debug_printk);
179 module_param(debug, uint, 0644);
180 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
182 module_param(debug_ratelimit, uint, 0644);
183 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
185 #else /* !CONFIG_CPU_FREQ_DEBUG */
187 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
188 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
190 #endif /* CONFIG_CPU_FREQ_DEBUG */
193 /*********************************************************************
194 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
195 *********************************************************************/
198 * adjust_jiffies - adjust the system "loops_per_jiffy"
200 * This function alters the system "loops_per_jiffy" for the clock
201 * speed change. Note that loops_per_jiffy cannot be updated on SMP
202 * systems as each CPU might be scaled differently. So, use the arch
203 * per-CPU loops_per_jiffy value wherever possible.
206 static unsigned long l_p_j_ref;
207 static unsigned int l_p_j_ref_freq;
209 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
211 if (ci->flags & CPUFREQ_CONST_LOOPS)
214 if (!l_p_j_ref_freq) {
215 l_p_j_ref = loops_per_jiffy;
216 l_p_j_ref_freq = ci->old;
217 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
219 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
220 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
221 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
222 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
223 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
227 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
232 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
233 * on frequency transition.
235 * This function calls the transition notifiers and the "adjust_jiffies"
236 * function. It is called twice on all CPU frequency changes that have
239 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
241 struct cpufreq_policy *policy;
243 BUG_ON(irqs_disabled());
245 freqs->flags = cpufreq_driver->flags;
246 dprintk("notification %u of frequency transition to %u kHz\n",
249 down_read(&cpufreq_notifier_rwsem);
251 policy = cpufreq_cpu_data[freqs->cpu];
254 case CPUFREQ_PRECHANGE:
255 /* detect if the driver reported a value as "old frequency"
256 * which is not equal to what the cpufreq core thinks is
259 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
260 if ((policy) && (policy->cpu == freqs->cpu) &&
261 (policy->cur) && (policy->cur != freqs->old)) {
262 dprintk(KERN_WARNING "Warning: CPU frequency is"
263 " %u, cpufreq assumed %u kHz.\n",
264 freqs->old, policy->cur);
265 freqs->old = policy->cur;
268 notifier_call_chain(&cpufreq_transition_notifier_list,
269 CPUFREQ_PRECHANGE, freqs);
270 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
273 case CPUFREQ_POSTCHANGE:
274 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
275 notifier_call_chain(&cpufreq_transition_notifier_list,
276 CPUFREQ_POSTCHANGE, freqs);
277 if (likely(policy) && likely(policy->cpu == freqs->cpu))
278 policy->cur = freqs->new;
281 up_read(&cpufreq_notifier_rwsem);
283 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
287 /*********************************************************************
289 *********************************************************************/
292 * cpufreq_parse_governor - parse a governor string
294 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
295 struct cpufreq_governor **governor)
299 if (cpufreq_driver->setpolicy) {
300 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
301 *policy = CPUFREQ_POLICY_PERFORMANCE;
303 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
304 *policy = CPUFREQ_POLICY_POWERSAVE;
309 struct cpufreq_governor *t;
310 mutex_lock(&cpufreq_governor_mutex);
311 if (!cpufreq_driver || !cpufreq_driver->target)
313 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
314 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
316 mutex_unlock(&cpufreq_governor_mutex);
321 mutex_unlock(&cpufreq_governor_mutex);
325 EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
328 /* drivers/base/cpu.c */
329 extern struct sysdev_class cpu_sysdev_class;
333 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
335 * Write out information from cpufreq_driver->policy[cpu]; object must be
339 #define show_one(file_name, object) \
340 static ssize_t show_##file_name \
341 (struct cpufreq_policy * policy, char *buf) \
343 return sprintf (buf, "%u\n", policy->object); \
346 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
347 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
348 show_one(scaling_min_freq, min);
349 show_one(scaling_max_freq, max);
350 show_one(scaling_cur_freq, cur);
353 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
355 #define store_one(file_name, object) \
356 static ssize_t store_##file_name \
357 (struct cpufreq_policy * policy, const char *buf, size_t count) \
359 unsigned int ret = -EINVAL; \
360 struct cpufreq_policy new_policy; \
362 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
366 ret = sscanf (buf, "%u", &new_policy.object); \
370 ret = cpufreq_set_policy(&new_policy); \
372 return ret ? ret : count; \
375 store_one(scaling_min_freq,min);
376 store_one(scaling_max_freq,max);
379 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
381 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
383 unsigned int cur_freq = cpufreq_get(policy->cpu);
385 return sprintf(buf, "<unknown>");
386 return sprintf(buf, "%u\n", cur_freq);
391 * show_scaling_governor - show the current policy for the specified CPU
393 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
395 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
396 return sprintf(buf, "powersave\n");
397 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
398 return sprintf(buf, "performance\n");
399 else if (policy->governor)
400 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
406 * store_scaling_governor - store policy for the specified CPU
408 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
409 const char *buf, size_t count)
411 unsigned int ret = -EINVAL;
412 char str_governor[16];
413 struct cpufreq_policy new_policy;
415 ret = cpufreq_get_policy(&new_policy, policy->cpu);
419 ret = sscanf (buf, "%15s", str_governor);
423 if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
426 ret = cpufreq_set_policy(&new_policy);
428 return ret ? ret : count;
432 * show_scaling_driver - show the cpufreq driver currently loaded
434 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
436 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
440 * show_scaling_available_governors - show the available CPUfreq governors
442 static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
446 struct cpufreq_governor *t;
448 if (!cpufreq_driver->target) {
449 i += sprintf(buf, "performance powersave");
453 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
454 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
456 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
459 i += sprintf(&buf[i], "\n");
463 * show_affected_cpus - show the CPUs affected by each transition
465 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
470 for_each_cpu_mask(cpu, policy->cpus) {
472 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
473 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
474 if (i >= (PAGE_SIZE - 5))
477 i += sprintf(&buf[i], "\n");
482 #define define_one_ro(_name) \
483 static struct freq_attr _name = \
484 __ATTR(_name, 0444, show_##_name, NULL)
486 #define define_one_ro0400(_name) \
487 static struct freq_attr _name = \
488 __ATTR(_name, 0400, show_##_name, NULL)
490 #define define_one_rw(_name) \
491 static struct freq_attr _name = \
492 __ATTR(_name, 0644, show_##_name, store_##_name)
494 define_one_ro0400(cpuinfo_cur_freq);
495 define_one_ro(cpuinfo_min_freq);
496 define_one_ro(cpuinfo_max_freq);
497 define_one_ro(scaling_available_governors);
498 define_one_ro(scaling_driver);
499 define_one_ro(scaling_cur_freq);
500 define_one_ro(affected_cpus);
501 define_one_rw(scaling_min_freq);
502 define_one_rw(scaling_max_freq);
503 define_one_rw(scaling_governor);
505 static struct attribute * default_attrs[] = {
506 &cpuinfo_min_freq.attr,
507 &cpuinfo_max_freq.attr,
508 &scaling_min_freq.attr,
509 &scaling_max_freq.attr,
511 &scaling_governor.attr,
512 &scaling_driver.attr,
513 &scaling_available_governors.attr,
517 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
518 #define to_attr(a) container_of(a,struct freq_attr,attr)
520 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
522 struct cpufreq_policy * policy = to_policy(kobj);
523 struct freq_attr * fattr = to_attr(attr);
525 policy = cpufreq_cpu_get(policy->cpu);
528 ret = fattr->show ? fattr->show(policy,buf) : -EIO;
529 cpufreq_cpu_put(policy);
533 static ssize_t store(struct kobject * kobj, struct attribute * attr,
534 const char * buf, size_t count)
536 struct cpufreq_policy * policy = to_policy(kobj);
537 struct freq_attr * fattr = to_attr(attr);
539 policy = cpufreq_cpu_get(policy->cpu);
542 ret = fattr->store ? fattr->store(policy,buf,count) : -EIO;
543 cpufreq_cpu_put(policy);
547 static void cpufreq_sysfs_release(struct kobject * kobj)
549 struct cpufreq_policy * policy = to_policy(kobj);
550 dprintk("last reference is dropped\n");
551 complete(&policy->kobj_unregister);
554 static struct sysfs_ops sysfs_ops = {
559 static struct kobj_type ktype_cpufreq = {
560 .sysfs_ops = &sysfs_ops,
561 .default_attrs = default_attrs,
562 .release = cpufreq_sysfs_release,
567 * cpufreq_add_dev - add a CPU device
569 * Adds the cpufreq interface for a CPU device.
571 static int cpufreq_add_dev (struct sys_device * sys_dev)
573 unsigned int cpu = sys_dev->id;
575 struct cpufreq_policy new_policy;
576 struct cpufreq_policy *policy;
577 struct freq_attr **drv_attr;
581 if (cpu_is_offline(cpu))
584 cpufreq_debug_disable_ratelimit();
585 dprintk("adding CPU %u\n", cpu);
588 /* check whether a different CPU already registered this
589 * CPU because it is in the same boat. */
590 policy = cpufreq_cpu_get(cpu);
591 if (unlikely(policy)) {
592 dprintk("CPU already managed, adding link\n");
593 sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
594 cpufreq_debug_enable_ratelimit();
599 if (!try_module_get(cpufreq_driver->owner)) {
604 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
611 policy->cpus = cpumask_of_cpu(cpu);
613 mutex_init(&policy->lock);
614 mutex_lock(&policy->lock);
615 init_completion(&policy->kobj_unregister);
616 INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
618 /* call driver. From then on the cpufreq must be able
619 * to accept all calls to ->verify and ->setpolicy for this CPU
621 ret = cpufreq_driver->init(policy);
623 dprintk("initialization failed\n");
624 mutex_unlock(&policy->lock);
628 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
630 /* prepare interface data */
631 policy->kobj.parent = &sys_dev->kobj;
632 policy->kobj.ktype = &ktype_cpufreq;
633 strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
635 ret = kobject_register(&policy->kobj);
637 mutex_unlock(&policy->lock);
638 goto err_out_driver_exit;
640 /* set up files for this cpu device */
641 drv_attr = cpufreq_driver->attr;
642 while ((drv_attr) && (*drv_attr)) {
643 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
646 if (cpufreq_driver->get)
647 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
648 if (cpufreq_driver->target)
649 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
651 spin_lock_irqsave(&cpufreq_driver_lock, flags);
652 for_each_cpu_mask(j, policy->cpus)
653 cpufreq_cpu_data[j] = policy;
654 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
655 policy->governor = NULL; /* to assure that the starting sequence is
656 * run in cpufreq_set_policy */
657 mutex_unlock(&policy->lock);
659 /* set default policy */
661 ret = cpufreq_set_policy(&new_policy);
663 dprintk("setting policy failed\n");
664 goto err_out_unregister;
667 module_put(cpufreq_driver->owner);
668 dprintk("initialization complete\n");
669 cpufreq_debug_enable_ratelimit();
675 spin_lock_irqsave(&cpufreq_driver_lock, flags);
676 for_each_cpu_mask(j, policy->cpus)
677 cpufreq_cpu_data[j] = NULL;
678 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
680 kobject_unregister(&policy->kobj);
681 wait_for_completion(&policy->kobj_unregister);
684 if (cpufreq_driver->exit)
685 cpufreq_driver->exit(policy);
691 module_put(cpufreq_driver->owner);
693 cpufreq_debug_enable_ratelimit();
699 * cpufreq_remove_dev - remove a CPU device
701 * Removes the cpufreq interface for a CPU device.
703 static int cpufreq_remove_dev (struct sys_device * sys_dev)
705 unsigned int cpu = sys_dev->id;
707 struct cpufreq_policy *data;
709 struct sys_device *cpu_sys_dev;
713 cpufreq_debug_disable_ratelimit();
714 dprintk("unregistering CPU %u\n", cpu);
716 spin_lock_irqsave(&cpufreq_driver_lock, flags);
717 data = cpufreq_cpu_data[cpu];
720 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
721 cpufreq_debug_enable_ratelimit();
724 cpufreq_cpu_data[cpu] = NULL;
728 /* if this isn't the CPU which is the parent of the kobj, we
729 * only need to unlink, put and exit
731 if (unlikely(cpu != data->cpu)) {
732 dprintk("removing link\n");
733 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
734 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
735 cpufreq_cpu_put(data);
736 cpufreq_debug_enable_ratelimit();
742 if (!kobject_get(&data->kobj)) {
743 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
744 cpufreq_debug_enable_ratelimit();
749 /* if we have other CPUs still registered, we need to unlink them,
750 * or else wait_for_completion below will lock up. Clean the
751 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
754 if (unlikely(cpus_weight(data->cpus) > 1)) {
755 for_each_cpu_mask(j, data->cpus) {
758 cpufreq_cpu_data[j] = NULL;
762 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
764 if (unlikely(cpus_weight(data->cpus) > 1)) {
765 for_each_cpu_mask(j, data->cpus) {
768 dprintk("removing link for cpu %u\n", j);
769 cpu_sys_dev = get_cpu_sysdev(j);
770 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
771 cpufreq_cpu_put(data);
775 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
778 mutex_lock(&data->lock);
779 if (cpufreq_driver->target)
780 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
781 mutex_unlock(&data->lock);
783 kobject_unregister(&data->kobj);
785 kobject_put(&data->kobj);
787 /* we need to make sure that the underlying kobj is actually
788 * not referenced anymore by anybody before we proceed with
791 dprintk("waiting for dropping of refcount\n");
792 wait_for_completion(&data->kobj_unregister);
793 dprintk("wait complete\n");
795 if (cpufreq_driver->exit)
796 cpufreq_driver->exit(data);
800 cpufreq_debug_enable_ratelimit();
806 static void handle_update(void *data)
808 unsigned int cpu = (unsigned int)(long)data;
809 dprintk("handle_update for cpu %u called\n", cpu);
810 cpufreq_update_policy(cpu);
814 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
816 * @old_freq: CPU frequency the kernel thinks the CPU runs at
817 * @new_freq: CPU frequency the CPU actually runs at
819 * We adjust to current frequency first, and need to clean up later. So either call
820 * to cpufreq_update_policy() or schedule handle_update()).
822 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
824 struct cpufreq_freqs freqs;
826 dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
827 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
830 freqs.old = old_freq;
831 freqs.new = new_freq;
832 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
833 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
838 * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
841 * This is the last known freq, without actually getting it from the driver.
842 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
844 unsigned int cpufreq_quick_get(unsigned int cpu)
846 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
847 unsigned int ret = 0;
850 mutex_lock(&policy->lock);
852 mutex_unlock(&policy->lock);
853 cpufreq_cpu_put(policy);
858 EXPORT_SYMBOL(cpufreq_quick_get);
862 * cpufreq_get - get the current CPU frequency (in kHz)
865 * Get the CPU current (static) CPU frequency
867 unsigned int cpufreq_get(unsigned int cpu)
869 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
870 unsigned int ret = 0;
875 if (!cpufreq_driver->get)
878 mutex_lock(&policy->lock);
880 ret = cpufreq_driver->get(cpu);
882 if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS))
884 /* verify no discrepancy between actual and saved value exists */
885 if (unlikely(ret != policy->cur)) {
886 cpufreq_out_of_sync(cpu, policy->cur, ret);
887 schedule_work(&policy->update);
891 mutex_unlock(&policy->lock);
894 cpufreq_cpu_put(policy);
898 EXPORT_SYMBOL(cpufreq_get);
902 * cpufreq_suspend - let the low level driver prepare for suspend
905 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
907 int cpu = sysdev->id;
908 unsigned int ret = 0;
909 unsigned int cur_freq = 0;
910 struct cpufreq_policy *cpu_policy;
912 dprintk("resuming cpu %u\n", cpu);
914 if (!cpu_online(cpu))
917 /* we may be lax here as interrupts are off. Nonetheless
918 * we need to grab the correct cpu policy, as to check
919 * whether we really run on this CPU.
922 cpu_policy = cpufreq_cpu_get(cpu);
926 /* only handle each CPU group once */
927 if (unlikely(cpu_policy->cpu != cpu)) {
928 cpufreq_cpu_put(cpu_policy);
932 if (cpufreq_driver->suspend) {
933 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
935 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
936 "step on CPU %u\n", cpu_policy->cpu);
937 cpufreq_cpu_put(cpu_policy);
943 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
946 if (cpufreq_driver->get)
947 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
949 if (!cur_freq || !cpu_policy->cur) {
950 printk(KERN_ERR "cpufreq: suspend failed to assert current "
951 "frequency is what timing core thinks it is.\n");
955 if (unlikely(cur_freq != cpu_policy->cur)) {
956 struct cpufreq_freqs freqs;
958 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
959 dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
960 "cpufreq assumed %u kHz.\n",
961 cur_freq, cpu_policy->cur);
964 freqs.old = cpu_policy->cur;
965 freqs.new = cur_freq;
967 notifier_call_chain(&cpufreq_transition_notifier_list,
968 CPUFREQ_SUSPENDCHANGE, &freqs);
969 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
971 cpu_policy->cur = cur_freq;
975 cpufreq_cpu_put(cpu_policy);
980 * cpufreq_resume - restore proper CPU frequency handling after resume
982 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
983 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
984 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
987 static int cpufreq_resume(struct sys_device * sysdev)
989 int cpu = sysdev->id;
990 unsigned int ret = 0;
991 struct cpufreq_policy *cpu_policy;
993 dprintk("resuming cpu %u\n", cpu);
995 if (!cpu_online(cpu))
998 /* we may be lax here as interrupts are off. Nonetheless
999 * we need to grab the correct cpu policy, as to check
1000 * whether we really run on this CPU.
1003 cpu_policy = cpufreq_cpu_get(cpu);
1007 /* only handle each CPU group once */
1008 if (unlikely(cpu_policy->cpu != cpu)) {
1009 cpufreq_cpu_put(cpu_policy);
1013 if (cpufreq_driver->resume) {
1014 ret = cpufreq_driver->resume(cpu_policy);
1016 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1017 "step on CPU %u\n", cpu_policy->cpu);
1018 cpufreq_cpu_put(cpu_policy);
1023 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1024 unsigned int cur_freq = 0;
1026 if (cpufreq_driver->get)
1027 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1029 if (!cur_freq || !cpu_policy->cur) {
1030 printk(KERN_ERR "cpufreq: resume failed to assert "
1031 "current frequency is what timing core "
1036 if (unlikely(cur_freq != cpu_policy->cur)) {
1037 struct cpufreq_freqs freqs;
1039 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1040 dprintk(KERN_WARNING "Warning: CPU frequency"
1041 "is %u, cpufreq assumed %u kHz.\n",
1042 cur_freq, cpu_policy->cur);
1045 freqs.old = cpu_policy->cur;
1046 freqs.new = cur_freq;
1048 notifier_call_chain(&cpufreq_transition_notifier_list,
1049 CPUFREQ_RESUMECHANGE, &freqs);
1050 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1052 cpu_policy->cur = cur_freq;
1057 schedule_work(&cpu_policy->update);
1058 cpufreq_cpu_put(cpu_policy);
1062 static struct sysdev_driver cpufreq_sysdev_driver = {
1063 .add = cpufreq_add_dev,
1064 .remove = cpufreq_remove_dev,
1065 .suspend = cpufreq_suspend,
1066 .resume = cpufreq_resume,
1070 /*********************************************************************
1071 * NOTIFIER LISTS INTERFACE *
1072 *********************************************************************/
1075 * cpufreq_register_notifier - register a driver with cpufreq
1076 * @nb: notifier function to register
1077 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1079 * Add a driver to one of two lists: either a list of drivers that
1080 * are notified about clock rate changes (once before and once after
1081 * the transition), or a list of drivers that are notified about
1082 * changes in cpufreq policy.
1084 * This function may sleep, and has the same return conditions as
1085 * notifier_chain_register.
1087 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1091 down_write(&cpufreq_notifier_rwsem);
1093 case CPUFREQ_TRANSITION_NOTIFIER:
1094 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
1096 case CPUFREQ_POLICY_NOTIFIER:
1097 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
1102 up_write(&cpufreq_notifier_rwsem);
1106 EXPORT_SYMBOL(cpufreq_register_notifier);
1110 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1111 * @nb: notifier block to be unregistered
1112 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1114 * Remove a driver from the CPU frequency notifier list.
1116 * This function may sleep, and has the same return conditions as
1117 * notifier_chain_unregister.
1119 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1123 down_write(&cpufreq_notifier_rwsem);
1125 case CPUFREQ_TRANSITION_NOTIFIER:
1126 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1128 case CPUFREQ_POLICY_NOTIFIER:
1129 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1134 up_write(&cpufreq_notifier_rwsem);
1138 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1141 /*********************************************************************
1143 *********************************************************************/
1146 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1147 unsigned int target_freq,
1148 unsigned int relation)
1150 int retval = -EINVAL;
1153 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1154 target_freq, relation);
1155 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1156 retval = cpufreq_driver->target(policy, target_freq, relation);
1158 unlock_cpu_hotplug();
1162 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1164 int cpufreq_driver_target(struct cpufreq_policy *policy,
1165 unsigned int target_freq,
1166 unsigned int relation)
1170 policy = cpufreq_cpu_get(policy->cpu);
1174 mutex_lock(&policy->lock);
1176 ret = __cpufreq_driver_target(policy, target_freq, relation);
1178 mutex_unlock(&policy->lock);
1180 cpufreq_cpu_put(policy);
1184 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1187 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1191 if (!try_module_get(policy->governor->owner))
1194 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1195 ret = policy->governor->governor(policy, event);
1197 /* we keep one module reference alive for each CPU governed by this CPU */
1198 if ((event != CPUFREQ_GOV_START) || ret)
1199 module_put(policy->governor->owner);
1200 if ((event == CPUFREQ_GOV_STOP) && !ret)
1201 module_put(policy->governor->owner);
1207 int cpufreq_governor(unsigned int cpu, unsigned int event)
1210 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1215 mutex_lock(&policy->lock);
1216 ret = __cpufreq_governor(policy, event);
1217 mutex_unlock(&policy->lock);
1219 cpufreq_cpu_put(policy);
1223 EXPORT_SYMBOL_GPL(cpufreq_governor);
1226 int cpufreq_register_governor(struct cpufreq_governor *governor)
1228 struct cpufreq_governor *t;
1233 mutex_lock(&cpufreq_governor_mutex);
1235 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1236 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1237 mutex_unlock(&cpufreq_governor_mutex);
1241 list_add(&governor->governor_list, &cpufreq_governor_list);
1243 mutex_unlock(&cpufreq_governor_mutex);
1247 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1250 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1255 mutex_lock(&cpufreq_governor_mutex);
1256 list_del(&governor->governor_list);
1257 mutex_unlock(&cpufreq_governor_mutex);
1260 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1264 /*********************************************************************
1265 * POLICY INTERFACE *
1266 *********************************************************************/
1269 * cpufreq_get_policy - get the current cpufreq_policy
1270 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1272 * Reads the current cpufreq policy.
1274 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1276 struct cpufreq_policy *cpu_policy;
1280 cpu_policy = cpufreq_cpu_get(cpu);
1284 mutex_lock(&cpu_policy->lock);
1285 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1286 mutex_unlock(&cpu_policy->lock);
1288 cpufreq_cpu_put(cpu_policy);
1292 EXPORT_SYMBOL(cpufreq_get_policy);
1295 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1299 cpufreq_debug_disable_ratelimit();
1300 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1301 policy->min, policy->max);
1303 memcpy(&policy->cpuinfo,
1305 sizeof(struct cpufreq_cpuinfo));
1307 /* verify the cpu speed can be set within this limit */
1308 ret = cpufreq_driver->verify(policy);
1312 down_read(&cpufreq_notifier_rwsem);
1314 /* adjust if necessary - all reasons */
1315 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1318 /* adjust if necessary - hardware incompatibility*/
1319 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1322 /* verify the cpu speed can be set within this limit,
1323 which might be different to the first one */
1324 ret = cpufreq_driver->verify(policy);
1326 up_read(&cpufreq_notifier_rwsem);
1330 /* notification of the new policy */
1331 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1334 up_read(&cpufreq_notifier_rwsem);
1336 data->min = policy->min;
1337 data->max = policy->max;
1339 dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1341 if (cpufreq_driver->setpolicy) {
1342 data->policy = policy->policy;
1343 dprintk("setting range\n");
1344 ret = cpufreq_driver->setpolicy(policy);
1346 if (policy->governor != data->governor) {
1347 /* save old, working values */
1348 struct cpufreq_governor *old_gov = data->governor;
1350 dprintk("governor switch\n");
1352 /* end old governor */
1354 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1356 /* start new governor */
1357 data->governor = policy->governor;
1358 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1359 /* new governor failed, so re-start old one */
1360 dprintk("starting governor %s failed\n", data->governor->name);
1362 data->governor = old_gov;
1363 __cpufreq_governor(data, CPUFREQ_GOV_START);
1368 /* might be a policy change, too, so fall through */
1370 dprintk("governor: change or update limits\n");
1371 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1375 cpufreq_debug_enable_ratelimit();
1380 * cpufreq_set_policy - set a new CPUFreq policy
1381 * @policy: policy to be set.
1383 * Sets a new CPU frequency and voltage scaling policy.
1385 int cpufreq_set_policy(struct cpufreq_policy *policy)
1388 struct cpufreq_policy *data;
1393 data = cpufreq_cpu_get(policy->cpu);
1398 mutex_lock(&data->lock);
1400 ret = __cpufreq_set_policy(data, policy);
1401 data->user_policy.min = data->min;
1402 data->user_policy.max = data->max;
1403 data->user_policy.policy = data->policy;
1404 data->user_policy.governor = data->governor;
1406 mutex_unlock(&data->lock);
1407 cpufreq_cpu_put(data);
1411 EXPORT_SYMBOL(cpufreq_set_policy);
1415 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1416 * @cpu: CPU which shall be re-evaluated
1418 * Usefull for policy notifiers which have different necessities
1419 * at different times.
1421 int cpufreq_update_policy(unsigned int cpu)
1423 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1424 struct cpufreq_policy policy;
1430 mutex_lock(&data->lock);
1432 dprintk("updating policy for CPU %u\n", cpu);
1435 sizeof(struct cpufreq_policy));
1436 policy.min = data->user_policy.min;
1437 policy.max = data->user_policy.max;
1438 policy.policy = data->user_policy.policy;
1439 policy.governor = data->user_policy.governor;
1441 /* BIOS might change freq behind our back
1442 -> ask driver for current freq and notify governors about a change */
1443 if (cpufreq_driver->get) {
1444 policy.cur = cpufreq_driver->get(cpu);
1446 dprintk("Driver did not initialize current freq");
1447 data->cur = policy.cur;
1449 if (data->cur != policy.cur)
1450 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1454 ret = __cpufreq_set_policy(data, &policy);
1456 mutex_unlock(&data->lock);
1458 cpufreq_cpu_put(data);
1461 EXPORT_SYMBOL(cpufreq_update_policy);
1463 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1464 unsigned long action, void *hcpu)
1466 unsigned int cpu = (unsigned long)hcpu;
1467 struct cpufreq_policy *policy;
1468 struct sys_device *sys_dev;
1470 sys_dev = get_cpu_sysdev(cpu);
1475 cpufreq_add_dev(sys_dev);
1477 case CPU_DOWN_PREPARE:
1479 * We attempt to put this cpu in lowest frequency
1480 * possible before going down. This will permit
1481 * hardware-managed P-State to switch other related
1482 * threads to min or higher speeds if possible.
1484 policy = cpufreq_cpu_data[cpu];
1486 cpufreq_driver_target(policy, policy->min,
1487 CPUFREQ_RELATION_H);
1491 cpufreq_remove_dev(sys_dev);
1498 static struct notifier_block cpufreq_cpu_notifier =
1500 .notifier_call = cpufreq_cpu_callback,
1503 /*********************************************************************
1504 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1505 *********************************************************************/
1508 * cpufreq_register_driver - register a CPU Frequency driver
1509 * @driver_data: A struct cpufreq_driver containing the values#
1510 * submitted by the CPU Frequency driver.
1512 * Registers a CPU Frequency driver to this core code. This code
1513 * returns zero on success, -EBUSY when another driver got here first
1514 * (and isn't unregistered in the meantime).
1517 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1519 unsigned long flags;
1522 if (!driver_data || !driver_data->verify || !driver_data->init ||
1523 ((!driver_data->setpolicy) && (!driver_data->target)))
1526 dprintk("trying to register driver %s\n", driver_data->name);
1528 if (driver_data->setpolicy)
1529 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1531 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1532 if (cpufreq_driver) {
1533 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1536 cpufreq_driver = driver_data;
1537 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1539 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1541 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1545 /* check for at least one working CPU */
1546 for (i=0; i<NR_CPUS; i++)
1547 if (cpufreq_cpu_data[i])
1550 /* if all ->init() calls failed, unregister */
1552 dprintk("no CPU initialized for driver %s\n", driver_data->name);
1553 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1555 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1556 cpufreq_driver = NULL;
1557 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1562 register_cpu_notifier(&cpufreq_cpu_notifier);
1563 dprintk("driver %s up and running\n", driver_data->name);
1564 cpufreq_debug_enable_ratelimit();
1569 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1573 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1575 * Unregister the current CPUFreq driver. Only call this if you have
1576 * the right to do so, i.e. if you have succeeded in initialising before!
1577 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1578 * currently not initialised.
1580 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1582 unsigned long flags;
1584 cpufreq_debug_disable_ratelimit();
1586 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1587 cpufreq_debug_enable_ratelimit();
1591 dprintk("unregistering driver %s\n", driver->name);
1593 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1594 unregister_cpu_notifier(&cpufreq_cpu_notifier);
1596 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1597 cpufreq_driver = NULL;
1598 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1602 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);