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
);
1445 if (data
->cur
!= policy
.cur
)
1446 cpufreq_out_of_sync(cpu
, data
->cur
, policy
.cur
);
1449 ret
= __cpufreq_set_policy(data
, &policy
);
1451 mutex_unlock(&data
->lock
);
1453 cpufreq_cpu_put(data
);
1456 EXPORT_SYMBOL(cpufreq_update_policy
);
1458 static int __cpuinit
cpufreq_cpu_callback(struct notifier_block
*nfb
,
1459 unsigned long action
, void *hcpu
)
1461 unsigned int cpu
= (unsigned long)hcpu
;
1462 struct cpufreq_policy
*policy
;
1463 struct sys_device
*sys_dev
;
1465 sys_dev
= get_cpu_sysdev(cpu
);
1470 cpufreq_add_dev(sys_dev
);
1472 case CPU_DOWN_PREPARE
:
1474 * We attempt to put this cpu in lowest frequency
1475 * possible before going down. This will permit
1476 * hardware-managed P-State to switch other related
1477 * threads to min or higher speeds if possible.
1479 policy
= cpufreq_cpu_data
[cpu
];
1481 cpufreq_driver_target(policy
, policy
->min
,
1482 CPUFREQ_RELATION_H
);
1486 cpufreq_remove_dev(sys_dev
);
1493 static struct notifier_block cpufreq_cpu_notifier
=
1495 .notifier_call
= cpufreq_cpu_callback
,
1498 /*********************************************************************
1499 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1500 *********************************************************************/
1503 * cpufreq_register_driver - register a CPU Frequency driver
1504 * @driver_data: A struct cpufreq_driver containing the values#
1505 * submitted by the CPU Frequency driver.
1507 * Registers a CPU Frequency driver to this core code. This code
1508 * returns zero on success, -EBUSY when another driver got here first
1509 * (and isn't unregistered in the meantime).
1512 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
1514 unsigned long flags
;
1517 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
1518 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
1521 dprintk("trying to register driver %s\n", driver_data
->name
);
1523 if (driver_data
->setpolicy
)
1524 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
1526 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1527 if (cpufreq_driver
) {
1528 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1531 cpufreq_driver
= driver_data
;
1532 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1534 ret
= sysdev_driver_register(&cpu_sysdev_class
,&cpufreq_sysdev_driver
);
1536 if ((!ret
) && !(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
1540 /* check for at least one working CPU */
1541 for (i
=0; i
<NR_CPUS
; i
++)
1542 if (cpufreq_cpu_data
[i
])
1545 /* if all ->init() calls failed, unregister */
1547 dprintk("no CPU initialized for driver %s\n", driver_data
->name
);
1548 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1550 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1551 cpufreq_driver
= NULL
;
1552 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1557 register_cpu_notifier(&cpufreq_cpu_notifier
);
1558 dprintk("driver %s up and running\n", driver_data
->name
);
1559 cpufreq_debug_enable_ratelimit();
1564 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
1568 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1570 * Unregister the current CPUFreq driver. Only call this if you have
1571 * the right to do so, i.e. if you have succeeded in initialising before!
1572 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1573 * currently not initialised.
1575 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
1577 unsigned long flags
;
1579 cpufreq_debug_disable_ratelimit();
1581 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
)) {
1582 cpufreq_debug_enable_ratelimit();
1586 dprintk("unregistering driver %s\n", driver
->name
);
1588 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1589 unregister_cpu_notifier(&cpufreq_cpu_notifier
);
1591 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1592 cpufreq_driver
= NULL
;
1593 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1597 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);