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/config.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/notifier.h>
23 #include <linux/cpufreq.h>
24 #include <linux/delay.h>
25 #include <linux/interrupt.h>
26 #include <linux/spinlock.h>
27 #include <linux/device.h>
28 #include <linux/slab.h>
29 #include <linux/cpu.h>
30 #include <linux/completion.h>
31 #include <linux/mutex.h>
33 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
36 * The "cpufreq driver" - the arch- or hardware-dependend 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 struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
42 static DEFINE_SPINLOCK(cpufreq_driver_lock);
44 /* internal prototypes */
45 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
46 static void handle_update(void *data);
49 * Two notifier lists: the "policy" list is involved in the
50 * validation process for a new CPU frequency policy; the
51 * "transition" list for kernel code that needs to handle
52 * changes to devices when the CPU clock speed changes.
53 * The mutex locks both lists.
55 static struct notifier_block *cpufreq_policy_notifier_list;
56 static struct notifier_block *cpufreq_transition_notifier_list;
57 static DECLARE_RWSEM (cpufreq_notifier_rwsem);
60 static LIST_HEAD(cpufreq_governor_list);
61 static DEFINE_MUTEX (cpufreq_governor_mutex);
63 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
65 struct cpufreq_policy *data;
71 /* get the cpufreq driver */
72 spin_lock_irqsave(&cpufreq_driver_lock, flags);
77 if (!try_module_get(cpufreq_driver->owner))
82 data = cpufreq_cpu_data[cpu];
85 goto err_out_put_module;
87 if (!kobject_get(&data->kobj))
88 goto err_out_put_module;
90 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);
103 void cpufreq_cpu_put(struct cpufreq_policy *data)
105 kobject_put(&data->kobj);
106 module_put(cpufreq_driver->owner);
108 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
111 /*********************************************************************
112 * UNIFIED DEBUG HELPERS *
113 *********************************************************************/
114 #ifdef CONFIG_CPU_FREQ_DEBUG
116 /* what part(s) of the CPUfreq subsystem are debugged? */
117 static unsigned int debug;
119 /* is the debug output ratelimit'ed using printk_ratelimit? User can
120 * set or modify this value.
122 static unsigned int debug_ratelimit = 1;
124 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
125 * loading of a cpufreq driver, temporarily disabled when a new policy
126 * is set, and disabled upon cpufreq driver removal
128 static unsigned int disable_ratelimit = 1;
129 static DEFINE_SPINLOCK(disable_ratelimit_lock);
131 static void cpufreq_debug_enable_ratelimit(void)
135 spin_lock_irqsave(&disable_ratelimit_lock, flags);
136 if (disable_ratelimit)
138 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
141 static void cpufreq_debug_disable_ratelimit(void)
145 spin_lock_irqsave(&disable_ratelimit_lock, flags);
147 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
150 void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
159 spin_lock_irqsave(&disable_ratelimit_lock, flags);
160 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
161 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
164 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
166 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
169 len += vsnprintf(&s[len], (256 - len), fmt, args);
177 EXPORT_SYMBOL(cpufreq_debug_printk);
180 module_param(debug, uint, 0644);
181 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
183 module_param(debug_ratelimit, uint, 0644);
184 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
186 #else /* !CONFIG_CPU_FREQ_DEBUG */
188 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
189 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
191 #endif /* CONFIG_CPU_FREQ_DEBUG */
194 /*********************************************************************
195 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
196 *********************************************************************/
199 * adjust_jiffies - adjust the system "loops_per_jiffy"
201 * This function alters the system "loops_per_jiffy" for the clock
202 * speed change. Note that loops_per_jiffy cannot be updated on SMP
203 * systems as each CPU might be scaled differently. So, use the arch
204 * per-CPU loops_per_jiffy value wherever possible.
207 static unsigned long l_p_j_ref;
208 static unsigned int l_p_j_ref_freq;
210 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
212 if (ci->flags & CPUFREQ_CONST_LOOPS)
215 if (!l_p_j_ref_freq) {
216 l_p_j_ref = loops_per_jiffy;
217 l_p_j_ref_freq = ci->old;
218 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
220 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
221 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
222 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
223 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
224 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
228 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
233 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
234 * on frequency transition.
236 * This function calls the transition notifiers and the "adjust_jiffies"
237 * function. It is called twice on all CPU frequency changes that have
240 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
242 struct cpufreq_policy *policy;
244 BUG_ON(irqs_disabled());
246 freqs->flags = cpufreq_driver->flags;
247 dprintk("notification %u of frequency transition to %u kHz\n",
250 down_read(&cpufreq_notifier_rwsem);
252 policy = cpufreq_cpu_data[freqs->cpu];
255 case CPUFREQ_PRECHANGE:
256 /* detect if the driver reported a value as "old frequency"
257 * which is not equal to what the cpufreq core thinks is
260 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
261 if ((policy) && (policy->cpu == freqs->cpu) &&
262 (policy->cur) && (policy->cur != freqs->old)) {
263 dprintk(KERN_WARNING "Warning: CPU frequency is"
264 " %u, cpufreq assumed %u kHz.\n",
265 freqs->old, policy->cur);
266 freqs->old = policy->cur;
269 notifier_call_chain(&cpufreq_transition_notifier_list,
270 CPUFREQ_PRECHANGE, freqs);
271 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
274 case CPUFREQ_POSTCHANGE:
275 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
276 notifier_call_chain(&cpufreq_transition_notifier_list,
277 CPUFREQ_POSTCHANGE, freqs);
278 if (likely(policy) && likely(policy->cpu == freqs->cpu))
279 policy->cur = freqs->new;
282 up_read(&cpufreq_notifier_rwsem);
284 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
288 /*********************************************************************
290 *********************************************************************/
293 * cpufreq_parse_governor - parse a governor string
295 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
296 struct cpufreq_governor **governor)
300 if (cpufreq_driver->setpolicy) {
301 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
302 *policy = CPUFREQ_POLICY_PERFORMANCE;
304 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
305 *policy = CPUFREQ_POLICY_POWERSAVE;
310 struct cpufreq_governor *t;
311 mutex_lock(&cpufreq_governor_mutex);
312 if (!cpufreq_driver || !cpufreq_driver->target)
314 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
315 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
317 mutex_unlock(&cpufreq_governor_mutex);
322 mutex_unlock(&cpufreq_governor_mutex);
326 EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
329 /* drivers/base/cpu.c */
330 extern struct sysdev_class cpu_sysdev_class;
334 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
336 * Write out information from cpufreq_driver->policy[cpu]; object must be
340 #define show_one(file_name, object) \
341 static ssize_t show_##file_name \
342 (struct cpufreq_policy * policy, char *buf) \
344 return sprintf (buf, "%u\n", policy->object); \
347 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
348 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
349 show_one(scaling_min_freq, min);
350 show_one(scaling_max_freq, max);
351 show_one(scaling_cur_freq, cur);
354 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
356 #define store_one(file_name, object) \
357 static ssize_t store_##file_name \
358 (struct cpufreq_policy * policy, const char *buf, size_t count) \
360 unsigned int ret = -EINVAL; \
361 struct cpufreq_policy new_policy; \
363 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
367 ret = sscanf (buf, "%u", &new_policy.object); \
371 ret = cpufreq_set_policy(&new_policy); \
373 return ret ? ret : count; \
376 store_one(scaling_min_freq,min);
377 store_one(scaling_max_freq,max);
380 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
382 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
384 unsigned int cur_freq = cpufreq_get(policy->cpu);
386 return sprintf(buf, "<unknown>");
387 return sprintf(buf, "%u\n", cur_freq);
392 * show_scaling_governor - show the current policy for the specified CPU
394 static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
396 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
397 return sprintf(buf, "powersave\n");
398 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
399 return sprintf(buf, "performance\n");
400 else if (policy->governor)
401 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
407 * store_scaling_governor - store policy for the specified CPU
409 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
410 const char *buf, size_t count)
412 unsigned int ret = -EINVAL;
413 char str_governor[16];
414 struct cpufreq_policy new_policy;
416 ret = cpufreq_get_policy(&new_policy, policy->cpu);
420 ret = sscanf (buf, "%15s", str_governor);
424 if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
427 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;
578 struct sys_device *cpu_sys_dev;
582 struct cpufreq_policy *managed_policy;
585 if (cpu_is_offline(cpu))
588 cpufreq_debug_disable_ratelimit();
589 dprintk("adding CPU %u\n", cpu);
592 /* check whether a different CPU already registered this
593 * CPU because it is in the same boat. */
594 policy = cpufreq_cpu_get(cpu);
595 if (unlikely(policy)) {
596 cpufreq_cpu_put(policy);
597 cpufreq_debug_enable_ratelimit();
602 if (!try_module_get(cpufreq_driver->owner)) {
607 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
614 policy->cpus = cpumask_of_cpu(cpu);
616 mutex_init(&policy->lock);
617 mutex_lock(&policy->lock);
618 init_completion(&policy->kobj_unregister);
619 INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
621 /* call driver. From then on the cpufreq must be able
622 * to accept all calls to ->verify and ->setpolicy for this CPU
624 ret = cpufreq_driver->init(policy);
626 dprintk("initialization failed\n");
627 mutex_unlock(&policy->lock);
632 for_each_cpu_mask(j, policy->cpus) {
636 /* check for existing affected CPUs. They may not be aware
637 * of it due to CPU Hotplug.
639 managed_policy = cpufreq_cpu_get(j);
640 if (unlikely(managed_policy)) {
641 spin_lock_irqsave(&cpufreq_driver_lock, flags);
642 managed_policy->cpus = policy->cpus;
643 cpufreq_cpu_data[cpu] = managed_policy;
644 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
646 dprintk("CPU already managed, adding link\n");
647 sysfs_create_link(&sys_dev->kobj,
648 &managed_policy->kobj, "cpufreq");
650 cpufreq_debug_enable_ratelimit();
651 mutex_unlock(&policy->lock);
653 goto err_out_driver_exit; /* call driver->exit() */
657 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
659 /* prepare interface data */
660 policy->kobj.parent = &sys_dev->kobj;
661 policy->kobj.ktype = &ktype_cpufreq;
662 strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
664 ret = kobject_register(&policy->kobj);
666 mutex_unlock(&policy->lock);
667 goto err_out_driver_exit;
669 /* set up files for this cpu device */
670 drv_attr = cpufreq_driver->attr;
671 while ((drv_attr) && (*drv_attr)) {
672 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
675 if (cpufreq_driver->get)
676 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
677 if (cpufreq_driver->target)
678 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
680 spin_lock_irqsave(&cpufreq_driver_lock, flags);
681 for_each_cpu_mask(j, policy->cpus)
682 cpufreq_cpu_data[j] = policy;
683 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
685 /* symlink affected CPUs */
686 for_each_cpu_mask(j, policy->cpus) {
692 dprintk("CPU already managed, adding link\n");
693 cpufreq_cpu_get(cpu);
694 cpu_sys_dev = get_cpu_sysdev(j);
695 sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
699 policy->governor = NULL; /* to assure that the starting sequence is
700 * run in cpufreq_set_policy */
701 mutex_unlock(&policy->lock);
703 /* set default policy */
705 ret = cpufreq_set_policy(&new_policy);
707 dprintk("setting policy failed\n");
708 goto err_out_unregister;
711 module_put(cpufreq_driver->owner);
712 dprintk("initialization complete\n");
713 cpufreq_debug_enable_ratelimit();
719 spin_lock_irqsave(&cpufreq_driver_lock, flags);
720 for_each_cpu_mask(j, policy->cpus)
721 cpufreq_cpu_data[j] = NULL;
722 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
724 kobject_unregister(&policy->kobj);
725 wait_for_completion(&policy->kobj_unregister);
728 if (cpufreq_driver->exit)
729 cpufreq_driver->exit(policy);
735 module_put(cpufreq_driver->owner);
737 cpufreq_debug_enable_ratelimit();
743 * cpufreq_remove_dev - remove a CPU device
745 * Removes the cpufreq interface for a CPU device.
747 static int cpufreq_remove_dev (struct sys_device * sys_dev)
749 unsigned int cpu = sys_dev->id;
751 struct cpufreq_policy *data;
753 struct sys_device *cpu_sys_dev;
757 cpufreq_debug_disable_ratelimit();
758 dprintk("unregistering CPU %u\n", cpu);
760 spin_lock_irqsave(&cpufreq_driver_lock, flags);
761 data = cpufreq_cpu_data[cpu];
764 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
765 cpufreq_debug_enable_ratelimit();
768 cpufreq_cpu_data[cpu] = NULL;
772 /* if this isn't the CPU which is the parent of the kobj, we
773 * only need to unlink, put and exit
775 if (unlikely(cpu != data->cpu)) {
776 dprintk("removing link\n");
777 cpu_clear(cpu, data->cpus);
778 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
779 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
780 cpufreq_cpu_put(data);
781 cpufreq_debug_enable_ratelimit();
787 if (!kobject_get(&data->kobj)) {
788 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
789 cpufreq_debug_enable_ratelimit();
794 /* if we have other CPUs still registered, we need to unlink them,
795 * or else wait_for_completion below will lock up. Clean the
796 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
799 if (unlikely(cpus_weight(data->cpus) > 1)) {
800 for_each_cpu_mask(j, data->cpus) {
803 cpufreq_cpu_data[j] = NULL;
807 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
809 if (unlikely(cpus_weight(data->cpus) > 1)) {
810 for_each_cpu_mask(j, data->cpus) {
813 dprintk("removing link for cpu %u\n", j);
814 cpu_sys_dev = get_cpu_sysdev(j);
815 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
816 cpufreq_cpu_put(data);
820 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
823 mutex_lock(&data->lock);
824 if (cpufreq_driver->target)
825 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
826 mutex_unlock(&data->lock);
828 kobject_unregister(&data->kobj);
830 kobject_put(&data->kobj);
832 /* we need to make sure that the underlying kobj is actually
833 * not referenced anymore by anybody before we proceed with
836 dprintk("waiting for dropping of refcount\n");
837 wait_for_completion(&data->kobj_unregister);
838 dprintk("wait complete\n");
840 if (cpufreq_driver->exit)
841 cpufreq_driver->exit(data);
845 cpufreq_debug_enable_ratelimit();
850 static void handle_update(void *data)
852 unsigned int cpu = (unsigned int)(long)data;
853 dprintk("handle_update for cpu %u called\n", cpu);
854 cpufreq_update_policy(cpu);
858 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
860 * @old_freq: CPU frequency the kernel thinks the CPU runs at
861 * @new_freq: CPU frequency the CPU actually runs at
863 * We adjust to current frequency first, and need to clean up later. So either call
864 * to cpufreq_update_policy() or schedule handle_update()).
866 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
868 struct cpufreq_freqs freqs;
870 dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
871 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
874 freqs.old = old_freq;
875 freqs.new = new_freq;
876 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
877 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
882 * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
885 * This is the last known freq, without actually getting it from the driver.
886 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
888 unsigned int cpufreq_quick_get(unsigned int cpu)
890 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
891 unsigned int ret = 0;
894 mutex_lock(&policy->lock);
896 mutex_unlock(&policy->lock);
897 cpufreq_cpu_put(policy);
902 EXPORT_SYMBOL(cpufreq_quick_get);
906 * cpufreq_get - get the current CPU frequency (in kHz)
909 * Get the CPU current (static) CPU frequency
911 unsigned int cpufreq_get(unsigned int cpu)
913 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
914 unsigned int ret = 0;
919 if (!cpufreq_driver->get)
922 mutex_lock(&policy->lock);
924 ret = cpufreq_driver->get(cpu);
926 if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
927 /* verify no discrepancy between actual and saved value exists */
928 if (unlikely(ret != policy->cur)) {
929 cpufreq_out_of_sync(cpu, policy->cur, ret);
930 schedule_work(&policy->update);
934 mutex_unlock(&policy->lock);
937 cpufreq_cpu_put(policy);
941 EXPORT_SYMBOL(cpufreq_get);
945 * cpufreq_suspend - let the low level driver prepare for suspend
948 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
950 int cpu = sysdev->id;
951 unsigned int ret = 0;
952 unsigned int cur_freq = 0;
953 struct cpufreq_policy *cpu_policy;
955 dprintk("resuming cpu %u\n", cpu);
957 if (!cpu_online(cpu))
960 /* we may be lax here as interrupts are off. Nonetheless
961 * we need to grab the correct cpu policy, as to check
962 * whether we really run on this CPU.
965 cpu_policy = cpufreq_cpu_get(cpu);
969 /* only handle each CPU group once */
970 if (unlikely(cpu_policy->cpu != cpu)) {
971 cpufreq_cpu_put(cpu_policy);
975 if (cpufreq_driver->suspend) {
976 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
978 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
979 "step on CPU %u\n", cpu_policy->cpu);
980 cpufreq_cpu_put(cpu_policy);
986 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
989 if (cpufreq_driver->get)
990 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
992 if (!cur_freq || !cpu_policy->cur) {
993 printk(KERN_ERR "cpufreq: suspend failed to assert current "
994 "frequency is what timing core thinks it is.\n");
998 if (unlikely(cur_freq != cpu_policy->cur)) {
999 struct cpufreq_freqs freqs;
1001 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1002 dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
1003 "cpufreq assumed %u kHz.\n",
1004 cur_freq, cpu_policy->cur);
1007 freqs.old = cpu_policy->cur;
1008 freqs.new = cur_freq;
1010 notifier_call_chain(&cpufreq_transition_notifier_list,
1011 CPUFREQ_SUSPENDCHANGE, &freqs);
1012 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1014 cpu_policy->cur = cur_freq;
1018 cpufreq_cpu_put(cpu_policy);
1023 * cpufreq_resume - restore proper CPU frequency handling after resume
1025 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1026 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1027 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1030 static int cpufreq_resume(struct sys_device * sysdev)
1032 int cpu = sysdev->id;
1033 unsigned int ret = 0;
1034 struct cpufreq_policy *cpu_policy;
1036 dprintk("resuming cpu %u\n", cpu);
1038 if (!cpu_online(cpu))
1041 /* we may be lax here as interrupts are off. Nonetheless
1042 * we need to grab the correct cpu policy, as to check
1043 * whether we really run on this CPU.
1046 cpu_policy = cpufreq_cpu_get(cpu);
1050 /* only handle each CPU group once */
1051 if (unlikely(cpu_policy->cpu != cpu)) {
1052 cpufreq_cpu_put(cpu_policy);
1056 if (cpufreq_driver->resume) {
1057 ret = cpufreq_driver->resume(cpu_policy);
1059 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1060 "step on CPU %u\n", cpu_policy->cpu);
1061 cpufreq_cpu_put(cpu_policy);
1066 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1067 unsigned int cur_freq = 0;
1069 if (cpufreq_driver->get)
1070 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1072 if (!cur_freq || !cpu_policy->cur) {
1073 printk(KERN_ERR "cpufreq: resume failed to assert "
1074 "current frequency is what timing core "
1079 if (unlikely(cur_freq != cpu_policy->cur)) {
1080 struct cpufreq_freqs freqs;
1082 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1083 dprintk(KERN_WARNING "Warning: CPU frequency"
1084 "is %u, cpufreq assumed %u kHz.\n",
1085 cur_freq, cpu_policy->cur);
1088 freqs.old = cpu_policy->cur;
1089 freqs.new = cur_freq;
1091 notifier_call_chain(&cpufreq_transition_notifier_list,
1092 CPUFREQ_RESUMECHANGE, &freqs);
1093 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1095 cpu_policy->cur = cur_freq;
1100 schedule_work(&cpu_policy->update);
1101 cpufreq_cpu_put(cpu_policy);
1105 static struct sysdev_driver cpufreq_sysdev_driver = {
1106 .add = cpufreq_add_dev,
1107 .remove = cpufreq_remove_dev,
1108 .suspend = cpufreq_suspend,
1109 .resume = cpufreq_resume,
1113 /*********************************************************************
1114 * NOTIFIER LISTS INTERFACE *
1115 *********************************************************************/
1118 * cpufreq_register_notifier - register a driver with cpufreq
1119 * @nb: notifier function to register
1120 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1122 * Add a driver to one of two lists: either a list of drivers that
1123 * are notified about clock rate changes (once before and once after
1124 * the transition), or a list of drivers that are notified about
1125 * changes in cpufreq policy.
1127 * This function may sleep, and has the same return conditions as
1128 * notifier_chain_register.
1130 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1134 down_write(&cpufreq_notifier_rwsem);
1136 case CPUFREQ_TRANSITION_NOTIFIER:
1137 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
1139 case CPUFREQ_POLICY_NOTIFIER:
1140 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
1145 up_write(&cpufreq_notifier_rwsem);
1149 EXPORT_SYMBOL(cpufreq_register_notifier);
1153 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1154 * @nb: notifier block to be unregistered
1155 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1157 * Remove a driver from the CPU frequency notifier list.
1159 * This function may sleep, and has the same return conditions as
1160 * notifier_chain_unregister.
1162 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1166 down_write(&cpufreq_notifier_rwsem);
1168 case CPUFREQ_TRANSITION_NOTIFIER:
1169 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1171 case CPUFREQ_POLICY_NOTIFIER:
1172 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1177 up_write(&cpufreq_notifier_rwsem);
1181 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1184 /*********************************************************************
1186 *********************************************************************/
1189 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1190 unsigned int target_freq,
1191 unsigned int relation)
1193 int retval = -EINVAL;
1196 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1197 target_freq, relation);
1198 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1199 retval = cpufreq_driver->target(policy, target_freq, relation);
1201 unlock_cpu_hotplug();
1205 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1207 int cpufreq_driver_target(struct cpufreq_policy *policy,
1208 unsigned int target_freq,
1209 unsigned int relation)
1213 policy = cpufreq_cpu_get(policy->cpu);
1217 mutex_lock(&policy->lock);
1219 ret = __cpufreq_driver_target(policy, target_freq, relation);
1221 mutex_unlock(&policy->lock);
1223 cpufreq_cpu_put(policy);
1226 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1229 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1233 if (!try_module_get(policy->governor->owner))
1236 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1237 ret = policy->governor->governor(policy, event);
1239 /* we keep one module reference alive for each CPU governed by this CPU */
1240 if ((event != CPUFREQ_GOV_START) || ret)
1241 module_put(policy->governor->owner);
1242 if ((event == CPUFREQ_GOV_STOP) && !ret)
1243 module_put(policy->governor->owner);
1249 int cpufreq_governor(unsigned int cpu, unsigned int event)
1252 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1257 mutex_lock(&policy->lock);
1258 ret = __cpufreq_governor(policy, event);
1259 mutex_unlock(&policy->lock);
1261 cpufreq_cpu_put(policy);
1264 EXPORT_SYMBOL_GPL(cpufreq_governor);
1267 int cpufreq_register_governor(struct cpufreq_governor *governor)
1269 struct cpufreq_governor *t;
1274 mutex_lock(&cpufreq_governor_mutex);
1276 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1277 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1278 mutex_unlock(&cpufreq_governor_mutex);
1282 list_add(&governor->governor_list, &cpufreq_governor_list);
1284 mutex_unlock(&cpufreq_governor_mutex);
1287 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1290 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1295 mutex_lock(&cpufreq_governor_mutex);
1296 list_del(&governor->governor_list);
1297 mutex_unlock(&cpufreq_governor_mutex);
1300 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1304 /*********************************************************************
1305 * POLICY INTERFACE *
1306 *********************************************************************/
1309 * cpufreq_get_policy - get the current cpufreq_policy
1310 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1312 * Reads the current cpufreq policy.
1314 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1316 struct cpufreq_policy *cpu_policy;
1320 cpu_policy = cpufreq_cpu_get(cpu);
1324 mutex_lock(&cpu_policy->lock);
1325 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1326 mutex_unlock(&cpu_policy->lock);
1328 cpufreq_cpu_put(cpu_policy);
1331 EXPORT_SYMBOL(cpufreq_get_policy);
1334 static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1338 cpufreq_debug_disable_ratelimit();
1339 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1340 policy->min, policy->max);
1342 memcpy(&policy->cpuinfo, &data->cpuinfo, sizeof(struct cpufreq_cpuinfo));
1344 /* verify the cpu speed can be set within this limit */
1345 ret = cpufreq_driver->verify(policy);
1349 down_read(&cpufreq_notifier_rwsem);
1351 /* adjust if necessary - all reasons */
1352 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1355 /* adjust if necessary - hardware incompatibility*/
1356 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1359 /* verify the cpu speed can be set within this limit,
1360 which might be different to the first one */
1361 ret = cpufreq_driver->verify(policy);
1363 up_read(&cpufreq_notifier_rwsem);
1367 /* notification of the new policy */
1368 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1371 up_read(&cpufreq_notifier_rwsem);
1373 data->min = policy->min;
1374 data->max = policy->max;
1376 dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1378 if (cpufreq_driver->setpolicy) {
1379 data->policy = policy->policy;
1380 dprintk("setting range\n");
1381 ret = cpufreq_driver->setpolicy(policy);
1383 if (policy->governor != data->governor) {
1384 /* save old, working values */
1385 struct cpufreq_governor *old_gov = data->governor;
1387 dprintk("governor switch\n");
1389 /* end old governor */
1391 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1393 /* start new governor */
1394 data->governor = policy->governor;
1395 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1396 /* new governor failed, so re-start old one */
1397 dprintk("starting governor %s failed\n", data->governor->name);
1399 data->governor = old_gov;
1400 __cpufreq_governor(data, CPUFREQ_GOV_START);
1405 /* might be a policy change, too, so fall through */
1407 dprintk("governor: change or update limits\n");
1408 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1412 cpufreq_debug_enable_ratelimit();
1417 * cpufreq_set_policy - set a new CPUFreq policy
1418 * @policy: policy to be set.
1420 * Sets a new CPU frequency and voltage scaling policy.
1422 int cpufreq_set_policy(struct cpufreq_policy *policy)
1425 struct cpufreq_policy *data;
1430 data = cpufreq_cpu_get(policy->cpu);
1435 mutex_lock(&data->lock);
1437 ret = __cpufreq_set_policy(data, policy);
1438 data->user_policy.min = data->min;
1439 data->user_policy.max = data->max;
1440 data->user_policy.policy = data->policy;
1441 data->user_policy.governor = data->governor;
1443 mutex_unlock(&data->lock);
1444 cpufreq_cpu_put(data);
1448 EXPORT_SYMBOL(cpufreq_set_policy);
1452 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1453 * @cpu: CPU which shall be re-evaluated
1455 * Usefull for policy notifiers which have different necessities
1456 * at different times.
1458 int cpufreq_update_policy(unsigned int cpu)
1460 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1461 struct cpufreq_policy policy;
1467 mutex_lock(&data->lock);
1469 dprintk("updating policy for CPU %u\n", cpu);
1470 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1471 policy.min = data->user_policy.min;
1472 policy.max = data->user_policy.max;
1473 policy.policy = data->user_policy.policy;
1474 policy.governor = data->user_policy.governor;
1476 /* BIOS might change freq behind our back
1477 -> ask driver for current freq and notify governors about a change */
1478 if (cpufreq_driver->get) {
1479 policy.cur = cpufreq_driver->get(cpu);
1481 dprintk("Driver did not initialize current freq");
1482 data->cur = policy.cur;
1484 if (data->cur != policy.cur)
1485 cpufreq_out_of_sync(cpu, data->cur, policy.cur);
1489 ret = __cpufreq_set_policy(data, &policy);
1491 mutex_unlock(&data->lock);
1493 cpufreq_cpu_put(data);
1496 EXPORT_SYMBOL(cpufreq_update_policy);
1498 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1499 unsigned long action, void *hcpu)
1501 unsigned int cpu = (unsigned long)hcpu;
1502 struct cpufreq_policy *policy;
1503 struct sys_device *sys_dev;
1505 sys_dev = get_cpu_sysdev(cpu);
1510 cpufreq_add_dev(sys_dev);
1512 case CPU_DOWN_PREPARE:
1514 * We attempt to put this cpu in lowest frequency
1515 * possible before going down. This will permit
1516 * hardware-managed P-State to switch other related
1517 * threads to min or higher speeds if possible.
1519 policy = cpufreq_cpu_data[cpu];
1521 cpufreq_driver_target(policy, policy->min,
1522 CPUFREQ_RELATION_H);
1526 cpufreq_remove_dev(sys_dev);
1533 static struct notifier_block cpufreq_cpu_notifier =
1535 .notifier_call = cpufreq_cpu_callback,
1538 /*********************************************************************
1539 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1540 *********************************************************************/
1543 * cpufreq_register_driver - register a CPU Frequency driver
1544 * @driver_data: A struct cpufreq_driver containing the values#
1545 * submitted by the CPU Frequency driver.
1547 * Registers a CPU Frequency driver to this core code. This code
1548 * returns zero on success, -EBUSY when another driver got here first
1549 * (and isn't unregistered in the meantime).
1552 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1554 unsigned long flags;
1557 if (!driver_data || !driver_data->verify || !driver_data->init ||
1558 ((!driver_data->setpolicy) && (!driver_data->target)))
1561 dprintk("trying to register driver %s\n", driver_data->name);
1563 if (driver_data->setpolicy)
1564 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1566 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1567 if (cpufreq_driver) {
1568 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1571 cpufreq_driver = driver_data;
1572 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1574 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1576 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1580 /* check for at least one working CPU */
1581 for (i=0; i<NR_CPUS; i++)
1582 if (cpufreq_cpu_data[i])
1585 /* if all ->init() calls failed, unregister */
1587 dprintk("no CPU initialized for driver %s\n", driver_data->name);
1588 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1590 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1591 cpufreq_driver = NULL;
1592 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1597 register_cpu_notifier(&cpufreq_cpu_notifier);
1598 dprintk("driver %s up and running\n", driver_data->name);
1599 cpufreq_debug_enable_ratelimit();
1604 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1608 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1610 * Unregister the current CPUFreq driver. Only call this if you have
1611 * the right to do so, i.e. if you have succeeded in initialising before!
1612 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1613 * currently not initialised.
1615 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1617 unsigned long flags;
1619 cpufreq_debug_disable_ratelimit();
1621 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1622 cpufreq_debug_enable_ratelimit();
1626 dprintk("unregistering driver %s\n", driver->name);
1628 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1629 unregister_cpu_notifier(&cpufreq_cpu_notifier);
1631 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1632 cpufreq_driver = NULL;
1633 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1637 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);