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>
30 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
33 * The "cpufreq driver" - the arch- or hardware-dependend low
34 * level driver of CPUFreq support, and its spinlock. This lock
35 * also protects the cpufreq_cpu_data array.
37 static struct cpufreq_driver
*cpufreq_driver
;
38 static struct cpufreq_policy
*cpufreq_cpu_data
[NR_CPUS
];
39 static DEFINE_SPINLOCK(cpufreq_driver_lock
);
41 /* internal prototypes */
42 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
);
43 static void handle_update(void *data
);
46 * Two notifier lists: the "policy" list is involved in the
47 * validation process for a new CPU frequency policy; the
48 * "transition" list for kernel code that needs to handle
49 * changes to devices when the CPU clock speed changes.
50 * The mutex locks both lists.
52 static struct notifier_block
*cpufreq_policy_notifier_list
;
53 static struct notifier_block
*cpufreq_transition_notifier_list
;
54 static DECLARE_RWSEM (cpufreq_notifier_rwsem
);
57 static LIST_HEAD(cpufreq_governor_list
);
58 static DECLARE_MUTEX (cpufreq_governor_sem
);
60 struct cpufreq_policy
* cpufreq_cpu_get(unsigned int cpu
)
62 struct cpufreq_policy
*data
;
68 /* get the cpufreq driver */
69 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
74 if (!try_module_get(cpufreq_driver
->owner
))
79 data
= cpufreq_cpu_data
[cpu
];
82 goto err_out_put_module
;
84 if (!kobject_get(&data
->kobj
))
85 goto err_out_put_module
;
88 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
93 module_put(cpufreq_driver
->owner
);
95 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
99 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
101 void cpufreq_cpu_put(struct cpufreq_policy
*data
)
103 kobject_put(&data
->kobj
);
104 module_put(cpufreq_driver
->owner
);
106 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
109 /*********************************************************************
110 * UNIFIED DEBUG HELPERS *
111 *********************************************************************/
112 #ifdef CONFIG_CPU_FREQ_DEBUG
114 /* what part(s) of the CPUfreq subsystem are debugged? */
115 static unsigned int debug
;
117 /* is the debug output ratelimit'ed using printk_ratelimit? User can
118 * set or modify this value.
120 static unsigned int debug_ratelimit
= 1;
122 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
123 * loading of a cpufreq driver, temporarily disabled when a new policy
124 * is set, and disabled upon cpufreq driver removal
126 static unsigned int disable_ratelimit
= 1;
127 static DEFINE_SPINLOCK(disable_ratelimit_lock
);
129 static void cpufreq_debug_enable_ratelimit(void)
133 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
134 if (disable_ratelimit
)
136 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
139 static void cpufreq_debug_disable_ratelimit(void)
143 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
145 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
148 void cpufreq_debug_printk(unsigned int type
, const char *prefix
, const char *fmt
, ...)
157 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
158 if (!disable_ratelimit
&& debug_ratelimit
&& !printk_ratelimit()) {
159 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
162 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
164 len
= snprintf(s
, 256, KERN_DEBUG
"%s: ", prefix
);
167 len
+= vsnprintf(&s
[len
], (256 - len
), fmt
, args
);
175 EXPORT_SYMBOL(cpufreq_debug_printk
);
178 module_param(debug
, uint
, 0644);
179 MODULE_PARM_DESC(debug
, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
181 module_param(debug_ratelimit
, uint
, 0644);
182 MODULE_PARM_DESC(debug_ratelimit
, "CPUfreq debugging: set to 0 to disable ratelimiting.");
184 #else /* !CONFIG_CPU_FREQ_DEBUG */
186 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
187 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
189 #endif /* CONFIG_CPU_FREQ_DEBUG */
192 /*********************************************************************
193 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
194 *********************************************************************/
197 * adjust_jiffies - adjust the system "loops_per_jiffy"
199 * This function alters the system "loops_per_jiffy" for the clock
200 * speed change. Note that loops_per_jiffy cannot be updated on SMP
201 * systems as each CPU might be scaled differently. So, use the arch
202 * per-CPU loops_per_jiffy value wherever possible.
205 static unsigned long l_p_j_ref
;
206 static unsigned int l_p_j_ref_freq
;
208 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
210 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
213 if (!l_p_j_ref_freq
) {
214 l_p_j_ref
= loops_per_jiffy
;
215 l_p_j_ref_freq
= ci
->old
;
216 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref
, l_p_j_ref_freq
);
218 if ((val
== CPUFREQ_PRECHANGE
&& ci
->old
< ci
->new) ||
219 (val
== CPUFREQ_POSTCHANGE
&& ci
->old
> ci
->new) ||
220 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
221 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
, ci
->new);
222 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy
, ci
->new);
226 static inline void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
) { return; }
231 * cpufreq_notify_transition - call notifier chain and adjust_jiffies on frequency transition
233 * This function calls the transition notifiers and the "adjust_jiffies" function. It is called
234 * twice on all CPU frequency changes that have external effects.
236 void cpufreq_notify_transition(struct cpufreq_freqs
*freqs
, unsigned int state
)
238 BUG_ON(irqs_disabled());
240 freqs
->flags
= cpufreq_driver
->flags
;
241 dprintk("notification %u of frequency transition to %u kHz\n", state
, freqs
->new);
243 down_read(&cpufreq_notifier_rwsem
);
245 case CPUFREQ_PRECHANGE
:
246 /* detect if the driver reported a value as "old frequency" which
247 * is not equal to what the cpufreq core thinks is "old frequency".
249 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
250 if ((likely(cpufreq_cpu_data
[freqs
->cpu
])) &&
251 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cpu
== freqs
->cpu
)) &&
252 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cur
)) &&
253 (unlikely(freqs
->old
!= cpufreq_cpu_data
[freqs
->cpu
]->cur
)))
255 dprintk(KERN_WARNING
"Warning: CPU frequency is %u, "
256 "cpufreq assumed %u kHz.\n", freqs
->old
, cpufreq_cpu_data
[freqs
->cpu
]->cur
);
257 freqs
->old
= cpufreq_cpu_data
[freqs
->cpu
]->cur
;
260 notifier_call_chain(&cpufreq_transition_notifier_list
, CPUFREQ_PRECHANGE
, freqs
);
261 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
263 case CPUFREQ_POSTCHANGE
:
264 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
265 notifier_call_chain(&cpufreq_transition_notifier_list
, CPUFREQ_POSTCHANGE
, freqs
);
266 if ((likely(cpufreq_cpu_data
[freqs
->cpu
])) &&
267 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cpu
== freqs
->cpu
)))
268 cpufreq_cpu_data
[freqs
->cpu
]->cur
= freqs
->new;
271 up_read(&cpufreq_notifier_rwsem
);
273 EXPORT_SYMBOL_GPL(cpufreq_notify_transition
);
277 /*********************************************************************
279 *********************************************************************/
282 * cpufreq_parse_governor - parse a governor string
284 static int cpufreq_parse_governor (char *str_governor
, unsigned int *policy
,
285 struct cpufreq_governor
**governor
)
289 if (cpufreq_driver
->setpolicy
) {
290 if (!strnicmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
291 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
293 } else if (!strnicmp(str_governor
, "powersave", CPUFREQ_NAME_LEN
)) {
294 *policy
= CPUFREQ_POLICY_POWERSAVE
;
299 struct cpufreq_governor
*t
;
300 down(&cpufreq_governor_sem
);
301 if (!cpufreq_driver
|| !cpufreq_driver
->target
)
303 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
304 if (!strnicmp(str_governor
,t
->name
,CPUFREQ_NAME_LEN
)) {
306 up(&cpufreq_governor_sem
);
311 up(&cpufreq_governor_sem
);
315 EXPORT_SYMBOL_GPL(cpufreq_parse_governor
);
318 /* drivers/base/cpu.c */
319 extern struct sysdev_class cpu_sysdev_class
;
323 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
325 * Write out information from cpufreq_driver->policy[cpu]; object must be
329 #define show_one(file_name, object) \
330 static ssize_t show_##file_name \
331 (struct cpufreq_policy * policy, char *buf) \
333 return sprintf (buf, "%u\n", policy->object); \
336 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
337 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
338 show_one(scaling_min_freq
, min
);
339 show_one(scaling_max_freq
, max
);
340 show_one(scaling_cur_freq
, cur
);
343 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
345 #define store_one(file_name, object) \
346 static ssize_t store_##file_name \
347 (struct cpufreq_policy * policy, const char *buf, size_t count) \
349 unsigned int ret = -EINVAL; \
350 struct cpufreq_policy new_policy; \
352 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
356 ret = sscanf (buf, "%u", &new_policy.object); \
360 ret = cpufreq_set_policy(&new_policy); \
362 return ret ? ret : count; \
365 store_one(scaling_min_freq
,min
);
366 store_one(scaling_max_freq
,max
);
369 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
371 static ssize_t
show_cpuinfo_cur_freq (struct cpufreq_policy
* policy
, char *buf
)
373 unsigned int cur_freq
= cpufreq_get(policy
->cpu
);
375 return sprintf(buf
, "<unknown>");
376 return sprintf(buf
, "%u\n", cur_freq
);
381 * show_scaling_governor - show the current policy for the specified CPU
383 static ssize_t
show_scaling_governor (struct cpufreq_policy
* policy
, char *buf
)
385 if(policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
386 return sprintf(buf
, "powersave\n");
387 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
388 return sprintf(buf
, "performance\n");
389 else if (policy
->governor
)
390 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", policy
->governor
->name
);
396 * store_scaling_governor - store policy for the specified CPU
398 static ssize_t
store_scaling_governor (struct cpufreq_policy
* policy
,
399 const char *buf
, size_t count
)
401 unsigned int ret
= -EINVAL
;
402 char str_governor
[16];
403 struct cpufreq_policy new_policy
;
405 ret
= cpufreq_get_policy(&new_policy
, policy
->cpu
);
409 ret
= sscanf (buf
, "%15s", str_governor
);
413 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
, &new_policy
.governor
))
416 ret
= cpufreq_set_policy(&new_policy
);
418 return ret
? ret
: count
;
422 * show_scaling_driver - show the cpufreq driver currently loaded
424 static ssize_t
show_scaling_driver (struct cpufreq_policy
* policy
, char *buf
)
426 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", cpufreq_driver
->name
);
430 * show_scaling_available_governors - show the available CPUfreq governors
432 static ssize_t
show_scaling_available_governors (struct cpufreq_policy
* policy
,
436 struct cpufreq_governor
*t
;
438 if (!cpufreq_driver
->target
) {
439 i
+= sprintf(buf
, "performance powersave");
443 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
444 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char)) - (CPUFREQ_NAME_LEN
+ 2)))
446 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_LEN
, "%s ", t
->name
);
449 i
+= sprintf(&buf
[i
], "\n");
453 * show_affected_cpus - show the CPUs affected by each transition
455 static ssize_t
show_affected_cpus (struct cpufreq_policy
* policy
, char *buf
)
460 for_each_cpu_mask(cpu
, policy
->cpus
) {
462 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
463 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
464 if (i
>= (PAGE_SIZE
- 5))
467 i
+= sprintf(&buf
[i
], "\n");
472 #define define_one_ro(_name) \
473 static struct freq_attr _name = \
474 __ATTR(_name, 0444, show_##_name, NULL)
476 #define define_one_ro0400(_name) \
477 static struct freq_attr _name = \
478 __ATTR(_name, 0400, show_##_name, NULL)
480 #define define_one_rw(_name) \
481 static struct freq_attr _name = \
482 __ATTR(_name, 0644, show_##_name, store_##_name)
484 define_one_ro0400(cpuinfo_cur_freq
);
485 define_one_ro(cpuinfo_min_freq
);
486 define_one_ro(cpuinfo_max_freq
);
487 define_one_ro(scaling_available_governors
);
488 define_one_ro(scaling_driver
);
489 define_one_ro(scaling_cur_freq
);
490 define_one_ro(affected_cpus
);
491 define_one_rw(scaling_min_freq
);
492 define_one_rw(scaling_max_freq
);
493 define_one_rw(scaling_governor
);
495 static struct attribute
* default_attrs
[] = {
496 &cpuinfo_min_freq
.attr
,
497 &cpuinfo_max_freq
.attr
,
498 &scaling_min_freq
.attr
,
499 &scaling_max_freq
.attr
,
501 &scaling_governor
.attr
,
502 &scaling_driver
.attr
,
503 &scaling_available_governors
.attr
,
507 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
508 #define to_attr(a) container_of(a,struct freq_attr,attr)
510 static ssize_t
show(struct kobject
* kobj
, struct attribute
* attr
,char * buf
)
512 struct cpufreq_policy
* policy
= to_policy(kobj
);
513 struct freq_attr
* fattr
= to_attr(attr
);
515 policy
= cpufreq_cpu_get(policy
->cpu
);
518 ret
= fattr
->show
? fattr
->show(policy
,buf
) : -EIO
;
519 cpufreq_cpu_put(policy
);
523 static ssize_t
store(struct kobject
* kobj
, struct attribute
* attr
,
524 const char * buf
, size_t count
)
526 struct cpufreq_policy
* policy
= to_policy(kobj
);
527 struct freq_attr
* fattr
= to_attr(attr
);
529 policy
= cpufreq_cpu_get(policy
->cpu
);
532 ret
= fattr
->store
? fattr
->store(policy
,buf
,count
) : -EIO
;
533 cpufreq_cpu_put(policy
);
537 static void cpufreq_sysfs_release(struct kobject
* kobj
)
539 struct cpufreq_policy
* policy
= to_policy(kobj
);
540 dprintk("last reference is dropped\n");
541 complete(&policy
->kobj_unregister
);
544 static struct sysfs_ops sysfs_ops
= {
549 static struct kobj_type ktype_cpufreq
= {
550 .sysfs_ops
= &sysfs_ops
,
551 .default_attrs
= default_attrs
,
552 .release
= cpufreq_sysfs_release
,
557 * cpufreq_add_dev - add a CPU device
559 * Adds the cpufreq interface for a CPU device.
561 static int cpufreq_add_dev (struct sys_device
* sys_dev
)
563 unsigned int cpu
= sys_dev
->id
;
565 struct cpufreq_policy new_policy
;
566 struct cpufreq_policy
*policy
;
567 struct freq_attr
**drv_attr
;
571 if (cpu_is_offline(cpu
))
574 cpufreq_debug_disable_ratelimit();
575 dprintk("adding CPU %u\n", cpu
);
578 /* check whether a different CPU already registered this
579 * CPU because it is in the same boat. */
580 policy
= cpufreq_cpu_get(cpu
);
581 if (unlikely(policy
)) {
582 dprintk("CPU already managed, adding link\n");
583 sysfs_create_link(&sys_dev
->kobj
, &policy
->kobj
, "cpufreq");
584 cpufreq_debug_enable_ratelimit();
589 if (!try_module_get(cpufreq_driver
->owner
)) {
594 policy
= kzalloc(sizeof(struct cpufreq_policy
), GFP_KERNEL
);
601 policy
->cpus
= cpumask_of_cpu(cpu
);
603 init_MUTEX_LOCKED(&policy
->lock
);
604 init_completion(&policy
->kobj_unregister
);
605 INIT_WORK(&policy
->update
, handle_update
, (void *)(long)cpu
);
607 /* call driver. From then on the cpufreq must be able
608 * to accept all calls to ->verify and ->setpolicy for this CPU
610 ret
= cpufreq_driver
->init(policy
);
612 dprintk("initialization failed\n");
616 memcpy(&new_policy
, policy
, sizeof(struct cpufreq_policy
));
618 /* prepare interface data */
619 policy
->kobj
.parent
= &sys_dev
->kobj
;
620 policy
->kobj
.ktype
= &ktype_cpufreq
;
621 strlcpy(policy
->kobj
.name
, "cpufreq", KOBJ_NAME_LEN
);
623 ret
= kobject_register(&policy
->kobj
);
625 goto err_out_driver_exit
;
627 /* set up files for this cpu device */
628 drv_attr
= cpufreq_driver
->attr
;
629 while ((drv_attr
) && (*drv_attr
)) {
630 sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
633 if (cpufreq_driver
->get
)
634 sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
635 if (cpufreq_driver
->target
)
636 sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
638 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
639 for_each_cpu_mask(j
, policy
->cpus
)
640 cpufreq_cpu_data
[j
] = policy
;
641 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
642 policy
->governor
= NULL
; /* to assure that the starting sequence is
643 * run in cpufreq_set_policy */
646 /* set default policy */
648 ret
= cpufreq_set_policy(&new_policy
);
650 dprintk("setting policy failed\n");
651 goto err_out_unregister
;
654 module_put(cpufreq_driver
->owner
);
655 dprintk("initialization complete\n");
656 cpufreq_debug_enable_ratelimit();
662 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
663 for_each_cpu_mask(j
, policy
->cpus
)
664 cpufreq_cpu_data
[j
] = NULL
;
665 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
667 kobject_unregister(&policy
->kobj
);
668 wait_for_completion(&policy
->kobj_unregister
);
671 if (cpufreq_driver
->exit
)
672 cpufreq_driver
->exit(policy
);
678 module_put(cpufreq_driver
->owner
);
680 cpufreq_debug_enable_ratelimit();
686 * cpufreq_remove_dev - remove a CPU device
688 * Removes the cpufreq interface for a CPU device.
690 static int cpufreq_remove_dev (struct sys_device
* sys_dev
)
692 unsigned int cpu
= sys_dev
->id
;
694 struct cpufreq_policy
*data
;
696 struct sys_device
*cpu_sys_dev
;
700 cpufreq_debug_disable_ratelimit();
701 dprintk("unregistering CPU %u\n", cpu
);
703 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
704 data
= cpufreq_cpu_data
[cpu
];
707 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
708 cpufreq_debug_enable_ratelimit();
711 cpufreq_cpu_data
[cpu
] = NULL
;
715 /* if this isn't the CPU which is the parent of the kobj, we
716 * only need to unlink, put and exit
718 if (unlikely(cpu
!= data
->cpu
)) {
719 dprintk("removing link\n");
720 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
721 sysfs_remove_link(&sys_dev
->kobj
, "cpufreq");
722 cpufreq_cpu_put(data
);
723 cpufreq_debug_enable_ratelimit();
729 if (!kobject_get(&data
->kobj
)) {
730 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
731 cpufreq_debug_enable_ratelimit();
736 /* if we have other CPUs still registered, we need to unlink them,
737 * or else wait_for_completion below will lock up. Clean the
738 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
741 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
742 for_each_cpu_mask(j
, data
->cpus
) {
745 cpufreq_cpu_data
[j
] = NULL
;
749 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
751 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
752 for_each_cpu_mask(j
, data
->cpus
) {
755 dprintk("removing link for cpu %u\n", j
);
756 cpu_sys_dev
= get_cpu_sysdev(j
);
757 sysfs_remove_link(&cpu_sys_dev
->kobj
, "cpufreq");
758 cpufreq_cpu_put(data
);
762 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
766 if (cpufreq_driver
->target
)
767 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
770 kobject_unregister(&data
->kobj
);
772 kobject_put(&data
->kobj
);
774 /* we need to make sure that the underlying kobj is actually
775 * not referenced anymore by anybody before we proceed with
778 dprintk("waiting for dropping of refcount\n");
779 wait_for_completion(&data
->kobj_unregister
);
780 dprintk("wait complete\n");
782 if (cpufreq_driver
->exit
)
783 cpufreq_driver
->exit(data
);
787 cpufreq_debug_enable_ratelimit();
793 static void handle_update(void *data
)
795 unsigned int cpu
= (unsigned int)(long)data
;
796 dprintk("handle_update for cpu %u called\n", cpu
);
797 cpufreq_update_policy(cpu
);
801 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
803 * @old_freq: CPU frequency the kernel thinks the CPU runs at
804 * @new_freq: CPU frequency the CPU actually runs at
806 * We adjust to current frequency first, and need to clean up later. So either call
807 * to cpufreq_update_policy() or schedule handle_update()).
809 static void cpufreq_out_of_sync(unsigned int cpu
, unsigned int old_freq
, unsigned int new_freq
)
811 struct cpufreq_freqs freqs
;
813 dprintk(KERN_WARNING
"Warning: CPU frequency out of sync: cpufreq and timing "
814 "core thinks of %u, is %u kHz.\n", old_freq
, new_freq
);
817 freqs
.old
= old_freq
;
818 freqs
.new = new_freq
;
819 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
820 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
825 * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
828 * This is the last known freq, without actually getting it from the driver.
829 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
831 unsigned int cpufreq_quick_get(unsigned int cpu
)
833 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
834 unsigned int ret
= 0;
840 cpufreq_cpu_put(policy
);
845 EXPORT_SYMBOL(cpufreq_quick_get
);
849 * cpufreq_get - get the current CPU frequency (in kHz)
852 * Get the CPU current (static) CPU frequency
854 unsigned int cpufreq_get(unsigned int cpu
)
856 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
857 unsigned int ret
= 0;
862 if (!cpufreq_driver
->get
)
867 ret
= cpufreq_driver
->get(cpu
);
869 if (ret
&& policy
->cur
&& !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
))
871 /* verify no discrepancy between actual and saved value exists */
872 if (unlikely(ret
!= policy
->cur
)) {
873 cpufreq_out_of_sync(cpu
, policy
->cur
, ret
);
874 schedule_work(&policy
->update
);
881 cpufreq_cpu_put(policy
);
885 EXPORT_SYMBOL(cpufreq_get
);
889 * cpufreq_suspend - let the low level driver prepare for suspend
892 static int cpufreq_suspend(struct sys_device
* sysdev
, pm_message_t pmsg
)
894 int cpu
= sysdev
->id
;
895 unsigned int ret
= 0;
896 unsigned int cur_freq
= 0;
897 struct cpufreq_policy
*cpu_policy
;
899 dprintk("resuming cpu %u\n", cpu
);
901 if (!cpu_online(cpu
))
904 /* we may be lax here as interrupts are off. Nonetheless
905 * we need to grab the correct cpu policy, as to check
906 * whether we really run on this CPU.
909 cpu_policy
= cpufreq_cpu_get(cpu
);
913 /* only handle each CPU group once */
914 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
915 cpufreq_cpu_put(cpu_policy
);
919 if (cpufreq_driver
->suspend
) {
920 ret
= cpufreq_driver
->suspend(cpu_policy
, pmsg
);
922 printk(KERN_ERR
"cpufreq: suspend failed in ->suspend "
923 "step on CPU %u\n", cpu_policy
->cpu
);
924 cpufreq_cpu_put(cpu_policy
);
930 if (cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)
933 if (cpufreq_driver
->get
)
934 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
936 if (!cur_freq
|| !cpu_policy
->cur
) {
937 printk(KERN_ERR
"cpufreq: suspend failed to assert current "
938 "frequency is what timing core thinks it is.\n");
942 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
943 struct cpufreq_freqs freqs
;
945 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
946 dprintk(KERN_DEBUG
"Warning: CPU frequency is %u, "
947 "cpufreq assumed %u kHz.\n",
948 cur_freq
, cpu_policy
->cur
);
951 freqs
.old
= cpu_policy
->cur
;
952 freqs
.new = cur_freq
;
954 notifier_call_chain(&cpufreq_transition_notifier_list
,
955 CPUFREQ_SUSPENDCHANGE
, &freqs
);
956 adjust_jiffies(CPUFREQ_SUSPENDCHANGE
, &freqs
);
958 cpu_policy
->cur
= cur_freq
;
962 cpufreq_cpu_put(cpu_policy
);
967 * cpufreq_resume - restore proper CPU frequency handling after resume
969 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
970 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
971 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
974 static int cpufreq_resume(struct sys_device
* sysdev
)
976 int cpu
= sysdev
->id
;
977 unsigned int ret
= 0;
978 struct cpufreq_policy
*cpu_policy
;
980 dprintk("resuming cpu %u\n", cpu
);
982 if (!cpu_online(cpu
))
985 /* we may be lax here as interrupts are off. Nonetheless
986 * we need to grab the correct cpu policy, as to check
987 * whether we really run on this CPU.
990 cpu_policy
= cpufreq_cpu_get(cpu
);
994 /* only handle each CPU group once */
995 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
996 cpufreq_cpu_put(cpu_policy
);
1000 if (cpufreq_driver
->resume
) {
1001 ret
= cpufreq_driver
->resume(cpu_policy
);
1003 printk(KERN_ERR
"cpufreq: resume failed in ->resume "
1004 "step on CPU %u\n", cpu_policy
->cpu
);
1005 cpufreq_cpu_put(cpu_policy
);
1010 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1011 unsigned int cur_freq
= 0;
1013 if (cpufreq_driver
->get
)
1014 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1016 if (!cur_freq
|| !cpu_policy
->cur
) {
1017 printk(KERN_ERR
"cpufreq: resume failed to assert "
1018 "current frequency is what timing core "
1023 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1024 struct cpufreq_freqs freqs
;
1026 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1027 dprintk(KERN_WARNING
"Warning: CPU frequency"
1028 "is %u, cpufreq assumed %u kHz.\n",
1029 cur_freq
, cpu_policy
->cur
);
1032 freqs
.old
= cpu_policy
->cur
;
1033 freqs
.new = cur_freq
;
1035 notifier_call_chain(&cpufreq_transition_notifier_list
,
1036 CPUFREQ_RESUMECHANGE
, &freqs
);
1037 adjust_jiffies(CPUFREQ_RESUMECHANGE
, &freqs
);
1039 cpu_policy
->cur
= cur_freq
;
1044 schedule_work(&cpu_policy
->update
);
1045 cpufreq_cpu_put(cpu_policy
);
1049 static struct sysdev_driver cpufreq_sysdev_driver
= {
1050 .add
= cpufreq_add_dev
,
1051 .remove
= cpufreq_remove_dev
,
1052 .suspend
= cpufreq_suspend
,
1053 .resume
= cpufreq_resume
,
1057 /*********************************************************************
1058 * NOTIFIER LISTS INTERFACE *
1059 *********************************************************************/
1062 * cpufreq_register_notifier - register a driver with cpufreq
1063 * @nb: notifier function to register
1064 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1066 * Add a driver to one of two lists: either a list of drivers that
1067 * are notified about clock rate changes (once before and once after
1068 * the transition), or a list of drivers that are notified about
1069 * changes in cpufreq policy.
1071 * This function may sleep, and has the same return conditions as
1072 * notifier_chain_register.
1074 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1078 down_write(&cpufreq_notifier_rwsem
);
1080 case CPUFREQ_TRANSITION_NOTIFIER
:
1081 ret
= notifier_chain_register(&cpufreq_transition_notifier_list
, nb
);
1083 case CPUFREQ_POLICY_NOTIFIER
:
1084 ret
= notifier_chain_register(&cpufreq_policy_notifier_list
, nb
);
1089 up_write(&cpufreq_notifier_rwsem
);
1093 EXPORT_SYMBOL(cpufreq_register_notifier
);
1097 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1098 * @nb: notifier block to be unregistered
1099 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1101 * Remove a driver from the CPU frequency notifier list.
1103 * This function may sleep, and has the same return conditions as
1104 * notifier_chain_unregister.
1106 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1110 down_write(&cpufreq_notifier_rwsem
);
1112 case CPUFREQ_TRANSITION_NOTIFIER
:
1113 ret
= notifier_chain_unregister(&cpufreq_transition_notifier_list
, nb
);
1115 case CPUFREQ_POLICY_NOTIFIER
:
1116 ret
= notifier_chain_unregister(&cpufreq_policy_notifier_list
, nb
);
1121 up_write(&cpufreq_notifier_rwsem
);
1125 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1128 /*********************************************************************
1130 *********************************************************************/
1133 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1134 unsigned int target_freq
,
1135 unsigned int relation
)
1137 int retval
= -EINVAL
;
1140 dprintk("target for CPU %u: %u kHz, relation %u\n", policy
->cpu
,
1141 target_freq
, relation
);
1142 if (cpu_online(policy
->cpu
) && cpufreq_driver
->target
)
1143 retval
= cpufreq_driver
->target(policy
, target_freq
, relation
);
1145 unlock_cpu_hotplug();
1149 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1151 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1152 unsigned int target_freq
,
1153 unsigned int relation
)
1157 policy
= cpufreq_cpu_get(policy
->cpu
);
1161 down(&policy
->lock
);
1163 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1167 cpufreq_cpu_put(policy
);
1171 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1174 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
)
1178 if (!try_module_get(policy
->governor
->owner
))
1181 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy
->cpu
, event
);
1182 ret
= policy
->governor
->governor(policy
, event
);
1184 /* we keep one module reference alive for each CPU governed by this CPU */
1185 if ((event
!= CPUFREQ_GOV_START
) || ret
)
1186 module_put(policy
->governor
->owner
);
1187 if ((event
== CPUFREQ_GOV_STOP
) && !ret
)
1188 module_put(policy
->governor
->owner
);
1194 int cpufreq_governor(unsigned int cpu
, unsigned int event
)
1197 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1202 down(&policy
->lock
);
1203 ret
= __cpufreq_governor(policy
, event
);
1206 cpufreq_cpu_put(policy
);
1210 EXPORT_SYMBOL_GPL(cpufreq_governor
);
1213 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1215 struct cpufreq_governor
*t
;
1220 down(&cpufreq_governor_sem
);
1222 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
1223 if (!strnicmp(governor
->name
,t
->name
,CPUFREQ_NAME_LEN
)) {
1224 up(&cpufreq_governor_sem
);
1228 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1230 up(&cpufreq_governor_sem
);
1234 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1237 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1242 down(&cpufreq_governor_sem
);
1243 list_del(&governor
->governor_list
);
1244 up(&cpufreq_governor_sem
);
1247 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1251 /*********************************************************************
1252 * POLICY INTERFACE *
1253 *********************************************************************/
1256 * cpufreq_get_policy - get the current cpufreq_policy
1257 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1259 * Reads the current cpufreq policy.
1261 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
1263 struct cpufreq_policy
*cpu_policy
;
1267 cpu_policy
= cpufreq_cpu_get(cpu
);
1271 down(&cpu_policy
->lock
);
1272 memcpy(policy
, cpu_policy
, sizeof(struct cpufreq_policy
));
1273 up(&cpu_policy
->lock
);
1275 cpufreq_cpu_put(cpu_policy
);
1279 EXPORT_SYMBOL(cpufreq_get_policy
);
1282 static int __cpufreq_set_policy(struct cpufreq_policy
*data
, struct cpufreq_policy
*policy
)
1286 cpufreq_debug_disable_ratelimit();
1287 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy
->cpu
,
1288 policy
->min
, policy
->max
);
1290 memcpy(&policy
->cpuinfo
,
1292 sizeof(struct cpufreq_cpuinfo
));
1294 /* verify the cpu speed can be set within this limit */
1295 ret
= cpufreq_driver
->verify(policy
);
1299 down_read(&cpufreq_notifier_rwsem
);
1301 /* adjust if necessary - all reasons */
1302 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_ADJUST
,
1305 /* adjust if necessary - hardware incompatibility*/
1306 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_INCOMPATIBLE
,
1309 /* verify the cpu speed can be set within this limit,
1310 which might be different to the first one */
1311 ret
= cpufreq_driver
->verify(policy
);
1313 up_read(&cpufreq_notifier_rwsem
);
1317 /* notification of the new policy */
1318 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_NOTIFY
,
1321 up_read(&cpufreq_notifier_rwsem
);
1323 data
->min
= policy
->min
;
1324 data
->max
= policy
->max
;
1326 dprintk("new min and max freqs are %u - %u kHz\n", data
->min
, data
->max
);
1328 if (cpufreq_driver
->setpolicy
) {
1329 data
->policy
= policy
->policy
;
1330 dprintk("setting range\n");
1331 ret
= cpufreq_driver
->setpolicy(policy
);
1333 if (policy
->governor
!= data
->governor
) {
1334 /* save old, working values */
1335 struct cpufreq_governor
*old_gov
= data
->governor
;
1337 dprintk("governor switch\n");
1339 /* end old governor */
1341 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
1343 /* start new governor */
1344 data
->governor
= policy
->governor
;
1345 if (__cpufreq_governor(data
, CPUFREQ_GOV_START
)) {
1346 /* new governor failed, so re-start old one */
1347 dprintk("starting governor %s failed\n", data
->governor
->name
);
1349 data
->governor
= old_gov
;
1350 __cpufreq_governor(data
, CPUFREQ_GOV_START
);
1355 /* might be a policy change, too, so fall through */
1357 dprintk("governor: change or update limits\n");
1358 __cpufreq_governor(data
, CPUFREQ_GOV_LIMITS
);
1362 cpufreq_debug_enable_ratelimit();
1367 * cpufreq_set_policy - set a new CPUFreq policy
1368 * @policy: policy to be set.
1370 * Sets a new CPU frequency and voltage scaling policy.
1372 int cpufreq_set_policy(struct cpufreq_policy
*policy
)
1375 struct cpufreq_policy
*data
;
1380 data
= cpufreq_cpu_get(policy
->cpu
);
1387 ret
= __cpufreq_set_policy(data
, policy
);
1388 data
->user_policy
.min
= data
->min
;
1389 data
->user_policy
.max
= data
->max
;
1390 data
->user_policy
.policy
= data
->policy
;
1391 data
->user_policy
.governor
= data
->governor
;
1394 cpufreq_cpu_put(data
);
1398 EXPORT_SYMBOL(cpufreq_set_policy
);
1402 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1403 * @cpu: CPU which shall be re-evaluated
1405 * Usefull for policy notifiers which have different necessities
1406 * at different times.
1408 int cpufreq_update_policy(unsigned int cpu
)
1410 struct cpufreq_policy
*data
= cpufreq_cpu_get(cpu
);
1411 struct cpufreq_policy policy
;
1419 dprintk("updating policy for CPU %u\n", cpu
);
1422 sizeof(struct cpufreq_policy
));
1423 policy
.min
= data
->user_policy
.min
;
1424 policy
.max
= data
->user_policy
.max
;
1425 policy
.policy
= data
->user_policy
.policy
;
1426 policy
.governor
= data
->user_policy
.governor
;
1428 ret
= __cpufreq_set_policy(data
, &policy
);
1432 cpufreq_cpu_put(data
);
1435 EXPORT_SYMBOL(cpufreq_update_policy
);
1437 static int __cpuinit
cpufreq_cpu_callback(struct notifier_block
*nfb
,
1438 unsigned long action
, void *hcpu
)
1440 unsigned int cpu
= (unsigned long)hcpu
;
1441 struct cpufreq_policy
*policy
;
1442 struct sys_device
*sys_dev
;
1444 sys_dev
= get_cpu_sysdev(cpu
);
1449 cpufreq_add_dev(sys_dev
);
1451 case CPU_DOWN_PREPARE
:
1453 * We attempt to put this cpu in lowest frequency
1454 * possible before going down. This will permit
1455 * hardware-managed P-State to switch other related
1456 * threads to min or higher speeds if possible.
1458 policy
= cpufreq_cpu_data
[cpu
];
1460 cpufreq_driver_target(policy
, policy
->min
,
1461 CPUFREQ_RELATION_H
);
1465 cpufreq_remove_dev(sys_dev
);
1472 static struct notifier_block cpufreq_cpu_notifier
=
1474 .notifier_call
= cpufreq_cpu_callback
,
1477 /*********************************************************************
1478 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1479 *********************************************************************/
1482 * cpufreq_register_driver - register a CPU Frequency driver
1483 * @driver_data: A struct cpufreq_driver containing the values#
1484 * submitted by the CPU Frequency driver.
1486 * Registers a CPU Frequency driver to this core code. This code
1487 * returns zero on success, -EBUSY when another driver got here first
1488 * (and isn't unregistered in the meantime).
1491 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
1493 unsigned long flags
;
1496 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
1497 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
1500 dprintk("trying to register driver %s\n", driver_data
->name
);
1502 if (driver_data
->setpolicy
)
1503 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
1505 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1506 if (cpufreq_driver
) {
1507 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1510 cpufreq_driver
= driver_data
;
1511 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1513 ret
= sysdev_driver_register(&cpu_sysdev_class
,&cpufreq_sysdev_driver
);
1515 if ((!ret
) && !(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
1519 /* check for at least one working CPU */
1520 for (i
=0; i
<NR_CPUS
; i
++)
1521 if (cpufreq_cpu_data
[i
])
1524 /* if all ->init() calls failed, unregister */
1526 dprintk("no CPU initialized for driver %s\n", driver_data
->name
);
1527 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1529 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1530 cpufreq_driver
= NULL
;
1531 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1536 register_cpu_notifier(&cpufreq_cpu_notifier
);
1537 dprintk("driver %s up and running\n", driver_data
->name
);
1538 cpufreq_debug_enable_ratelimit();
1543 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
1547 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1549 * Unregister the current CPUFreq driver. Only call this if you have
1550 * the right to do so, i.e. if you have succeeded in initialising before!
1551 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1552 * currently not initialised.
1554 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
1556 unsigned long flags
;
1558 cpufreq_debug_disable_ratelimit();
1560 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
)) {
1561 cpufreq_debug_enable_ratelimit();
1565 dprintk("unregistering driver %s\n", driver
->name
);
1567 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1568 unregister_cpu_notifier(&cpufreq_cpu_notifier
);
1570 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1571 cpufreq_driver
= NULL
;
1572 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1576 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);