2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10 * Fix handling for CPU hotplug -- affected CPUs
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/notifier.h>
22 #include <linux/cpufreq.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/device.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
36 * The "cpufreq driver" - the arch- or hardware-dependent low
37 * level driver of CPUFreq support, and its spinlock. This lock
38 * also protects the cpufreq_cpu_data array.
40 static struct cpufreq_driver
*cpufreq_driver
;
41 static DEFINE_PER_CPU(struct cpufreq_policy
*, cpufreq_cpu_data
);
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static DEFINE_PER_CPU(struct cpufreq_governor
*, cpufreq_cpu_governor
);
46 static DEFINE_SPINLOCK(cpufreq_driver_lock
);
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
52 * The rules for this semaphore:
53 * - Any routine that wants to read from the policy structure will
54 * do a down_read on this semaphore.
55 * - Any routine that will write to the policy structure and/or may take away
56 * the policy altogether (eg. CPU hotplug), will hold this lock in write
57 * mode before doing so.
60 * - All holders of the lock should check to make sure that the CPU they
61 * are concerned with are online after they get the lock.
62 * - Governor routines that can be called in cpufreq hotplug path should not
63 * take this sem as top level hotplug notifier handler takes this.
65 static DEFINE_PER_CPU(int, policy_cpu
);
66 static DEFINE_PER_CPU(struct rw_semaphore
, cpu_policy_rwsem
);
68 #define lock_policy_rwsem(mode, cpu) \
69 int lock_policy_rwsem_##mode \
72 int policy_cpu = per_cpu(policy_cpu, cpu); \
73 BUG_ON(policy_cpu == -1); \
74 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
75 if (unlikely(!cpu_online(cpu))) { \
76 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
83 lock_policy_rwsem(read
, cpu
);
84 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read
);
86 lock_policy_rwsem(write
, cpu
);
87 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write
);
89 void unlock_policy_rwsem_read(int cpu
)
91 int policy_cpu
= per_cpu(policy_cpu
, cpu
);
92 BUG_ON(policy_cpu
== -1);
93 up_read(&per_cpu(cpu_policy_rwsem
, policy_cpu
));
95 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read
);
97 void unlock_policy_rwsem_write(int cpu
)
99 int policy_cpu
= per_cpu(policy_cpu
, cpu
);
100 BUG_ON(policy_cpu
== -1);
101 up_write(&per_cpu(cpu_policy_rwsem
, policy_cpu
));
103 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write
);
106 /* internal prototypes */
107 static int __cpufreq_governor(struct cpufreq_policy
*policy
,
109 static unsigned int __cpufreq_get(unsigned int cpu
);
110 static void handle_update(struct work_struct
*work
);
113 * Two notifier lists: the "policy" list is involved in the
114 * validation process for a new CPU frequency policy; the
115 * "transition" list for kernel code that needs to handle
116 * changes to devices when the CPU clock speed changes.
117 * The mutex locks both lists.
119 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list
);
120 static struct srcu_notifier_head cpufreq_transition_notifier_list
;
122 static bool init_cpufreq_transition_notifier_list_called
;
123 static int __init
init_cpufreq_transition_notifier_list(void)
125 srcu_init_notifier_head(&cpufreq_transition_notifier_list
);
126 init_cpufreq_transition_notifier_list_called
= true;
129 pure_initcall(init_cpufreq_transition_notifier_list
);
131 static LIST_HEAD(cpufreq_governor_list
);
132 static DEFINE_MUTEX(cpufreq_governor_mutex
);
134 struct cpufreq_policy
*cpufreq_cpu_get(unsigned int cpu
)
136 struct cpufreq_policy
*data
;
139 if (cpu
>= nr_cpu_ids
)
142 /* get the cpufreq driver */
143 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
148 if (!try_module_get(cpufreq_driver
->owner
))
153 data
= per_cpu(cpufreq_cpu_data
, cpu
);
156 goto err_out_put_module
;
158 if (!kobject_get(&data
->kobj
))
159 goto err_out_put_module
;
161 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
165 module_put(cpufreq_driver
->owner
);
167 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
171 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
174 void cpufreq_cpu_put(struct cpufreq_policy
*data
)
176 kobject_put(&data
->kobj
);
177 module_put(cpufreq_driver
->owner
);
179 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
182 /*********************************************************************
183 * UNIFIED DEBUG HELPERS *
184 *********************************************************************/
185 #ifdef CONFIG_CPU_FREQ_DEBUG
187 /* what part(s) of the CPUfreq subsystem are debugged? */
188 static unsigned int debug
;
190 /* is the debug output ratelimit'ed using printk_ratelimit? User can
191 * set or modify this value.
193 static unsigned int debug_ratelimit
= 1;
195 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
196 * loading of a cpufreq driver, temporarily disabled when a new policy
197 * is set, and disabled upon cpufreq driver removal
199 static unsigned int disable_ratelimit
= 1;
200 static DEFINE_SPINLOCK(disable_ratelimit_lock
);
202 static void cpufreq_debug_enable_ratelimit(void)
206 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
207 if (disable_ratelimit
)
209 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
212 static void cpufreq_debug_disable_ratelimit(void)
216 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
218 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
221 void cpufreq_debug_printk(unsigned int type
, const char *prefix
,
222 const char *fmt
, ...)
231 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
232 if (!disable_ratelimit
&& debug_ratelimit
233 && !printk_ratelimit()) {
234 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
237 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
239 len
= snprintf(s
, 256, KERN_DEBUG
"%s: ", prefix
);
242 len
+= vsnprintf(&s
[len
], (256 - len
), fmt
, args
);
250 EXPORT_SYMBOL(cpufreq_debug_printk
);
253 module_param(debug
, uint
, 0644);
254 MODULE_PARM_DESC(debug
, "CPUfreq debugging: add 1 to debug core,"
255 " 2 to debug drivers, and 4 to debug governors.");
257 module_param(debug_ratelimit
, uint
, 0644);
258 MODULE_PARM_DESC(debug_ratelimit
, "CPUfreq debugging:"
259 " set to 0 to disable ratelimiting.");
261 #else /* !CONFIG_CPU_FREQ_DEBUG */
263 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
264 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
266 #endif /* CONFIG_CPU_FREQ_DEBUG */
269 /*********************************************************************
270 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
271 *********************************************************************/
274 * adjust_jiffies - adjust the system "loops_per_jiffy"
276 * This function alters the system "loops_per_jiffy" for the clock
277 * speed change. Note that loops_per_jiffy cannot be updated on SMP
278 * systems as each CPU might be scaled differently. So, use the arch
279 * per-CPU loops_per_jiffy value wherever possible.
282 static unsigned long l_p_j_ref
;
283 static unsigned int l_p_j_ref_freq
;
285 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
287 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
290 if (!l_p_j_ref_freq
) {
291 l_p_j_ref
= loops_per_jiffy
;
292 l_p_j_ref_freq
= ci
->old
;
293 dprintk("saving %lu as reference value for loops_per_jiffy; "
294 "freq is %u kHz\n", l_p_j_ref
, l_p_j_ref_freq
);
296 if ((val
== CPUFREQ_PRECHANGE
&& ci
->old
< ci
->new) ||
297 (val
== CPUFREQ_POSTCHANGE
&& ci
->old
> ci
->new) ||
298 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
299 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
,
301 dprintk("scaling loops_per_jiffy to %lu "
302 "for frequency %u kHz\n", loops_per_jiffy
, ci
->new);
306 static inline void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
314 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
315 * on frequency transition.
317 * This function calls the transition notifiers and the "adjust_jiffies"
318 * function. It is called twice on all CPU frequency changes that have
321 void cpufreq_notify_transition(struct cpufreq_freqs
*freqs
, unsigned int state
)
323 struct cpufreq_policy
*policy
;
325 BUG_ON(irqs_disabled());
327 freqs
->flags
= cpufreq_driver
->flags
;
328 dprintk("notification %u of frequency transition to %u kHz\n",
331 policy
= per_cpu(cpufreq_cpu_data
, freqs
->cpu
);
334 case CPUFREQ_PRECHANGE
:
335 /* detect if the driver reported a value as "old frequency"
336 * which is not equal to what the cpufreq core thinks is
339 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
340 if ((policy
) && (policy
->cpu
== freqs
->cpu
) &&
341 (policy
->cur
) && (policy
->cur
!= freqs
->old
)) {
342 dprintk("Warning: CPU frequency is"
343 " %u, cpufreq assumed %u kHz.\n",
344 freqs
->old
, policy
->cur
);
345 freqs
->old
= policy
->cur
;
348 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
349 CPUFREQ_PRECHANGE
, freqs
);
350 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
353 case CPUFREQ_POSTCHANGE
:
354 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
355 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
356 CPUFREQ_POSTCHANGE
, freqs
);
357 if (likely(policy
) && likely(policy
->cpu
== freqs
->cpu
))
358 policy
->cur
= freqs
->new;
362 EXPORT_SYMBOL_GPL(cpufreq_notify_transition
);
366 /*********************************************************************
368 *********************************************************************/
370 static struct cpufreq_governor
*__find_governor(const char *str_governor
)
372 struct cpufreq_governor
*t
;
374 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
)
375 if (!strnicmp(str_governor
, t
->name
, CPUFREQ_NAME_LEN
))
382 * cpufreq_parse_governor - parse a governor string
384 static int cpufreq_parse_governor(char *str_governor
, unsigned int *policy
,
385 struct cpufreq_governor
**governor
)
392 if (cpufreq_driver
->setpolicy
) {
393 if (!strnicmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
394 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
396 } else if (!strnicmp(str_governor
, "powersave",
398 *policy
= CPUFREQ_POLICY_POWERSAVE
;
401 } else if (cpufreq_driver
->target
) {
402 struct cpufreq_governor
*t
;
404 mutex_lock(&cpufreq_governor_mutex
);
406 t
= __find_governor(str_governor
);
409 char *name
= kasprintf(GFP_KERNEL
, "cpufreq_%s",
415 mutex_unlock(&cpufreq_governor_mutex
);
416 ret
= request_module("%s", name
);
417 mutex_lock(&cpufreq_governor_mutex
);
420 t
= __find_governor(str_governor
);
431 mutex_unlock(&cpufreq_governor_mutex
);
439 * cpufreq_per_cpu_attr_read() / show_##file_name() -
440 * print out cpufreq information
442 * Write out information from cpufreq_driver->policy[cpu]; object must be
446 #define show_one(file_name, object) \
447 static ssize_t show_##file_name \
448 (struct cpufreq_policy *policy, char *buf) \
450 return sprintf(buf, "%u\n", policy->object); \
453 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
454 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
455 show_one(cpuinfo_transition_latency
, cpuinfo
.transition_latency
);
456 show_one(scaling_min_freq
, min
);
457 show_one(scaling_max_freq
, max
);
458 show_one(scaling_cur_freq
, cur
);
460 static int __cpufreq_set_policy(struct cpufreq_policy
*data
,
461 struct cpufreq_policy
*policy
);
464 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
466 #define store_one(file_name, object) \
467 static ssize_t store_##file_name \
468 (struct cpufreq_policy *policy, const char *buf, size_t count) \
470 unsigned int ret = -EINVAL; \
471 struct cpufreq_policy new_policy; \
473 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
477 ret = sscanf(buf, "%u", &new_policy.object); \
481 ret = __cpufreq_set_policy(policy, &new_policy); \
482 policy->user_policy.object = policy->object; \
484 return ret ? ret : count; \
487 store_one(scaling_min_freq
, min
);
488 store_one(scaling_max_freq
, max
);
491 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
493 static ssize_t
show_cpuinfo_cur_freq(struct cpufreq_policy
*policy
,
496 unsigned int cur_freq
= __cpufreq_get(policy
->cpu
);
498 return sprintf(buf
, "<unknown>");
499 return sprintf(buf
, "%u\n", cur_freq
);
504 * show_scaling_governor - show the current policy for the specified CPU
506 static ssize_t
show_scaling_governor(struct cpufreq_policy
*policy
, char *buf
)
508 if (policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
509 return sprintf(buf
, "powersave\n");
510 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
511 return sprintf(buf
, "performance\n");
512 else if (policy
->governor
)
513 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n",
514 policy
->governor
->name
);
520 * store_scaling_governor - store policy for the specified CPU
522 static ssize_t
store_scaling_governor(struct cpufreq_policy
*policy
,
523 const char *buf
, size_t count
)
525 unsigned int ret
= -EINVAL
;
526 char str_governor
[16];
527 struct cpufreq_policy new_policy
;
529 ret
= cpufreq_get_policy(&new_policy
, policy
->cpu
);
533 ret
= sscanf(buf
, "%15s", str_governor
);
537 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
,
538 &new_policy
.governor
))
541 /* Do not use cpufreq_set_policy here or the user_policy.max
542 will be wrongly overridden */
543 ret
= __cpufreq_set_policy(policy
, &new_policy
);
545 policy
->user_policy
.policy
= policy
->policy
;
546 policy
->user_policy
.governor
= policy
->governor
;
555 * show_scaling_driver - show the cpufreq driver currently loaded
557 static ssize_t
show_scaling_driver(struct cpufreq_policy
*policy
, char *buf
)
559 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", cpufreq_driver
->name
);
563 * show_scaling_available_governors - show the available CPUfreq governors
565 static ssize_t
show_scaling_available_governors(struct cpufreq_policy
*policy
,
569 struct cpufreq_governor
*t
;
571 if (!cpufreq_driver
->target
) {
572 i
+= sprintf(buf
, "performance powersave");
576 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
577 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char))
578 - (CPUFREQ_NAME_LEN
+ 2)))
580 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_LEN
, "%s ", t
->name
);
583 i
+= sprintf(&buf
[i
], "\n");
587 static ssize_t
show_cpus(const struct cpumask
*mask
, char *buf
)
592 for_each_cpu(cpu
, mask
) {
594 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
595 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
596 if (i
>= (PAGE_SIZE
- 5))
599 i
+= sprintf(&buf
[i
], "\n");
604 * show_related_cpus - show the CPUs affected by each transition even if
605 * hw coordination is in use
607 static ssize_t
show_related_cpus(struct cpufreq_policy
*policy
, char *buf
)
609 if (cpumask_empty(policy
->related_cpus
))
610 return show_cpus(policy
->cpus
, buf
);
611 return show_cpus(policy
->related_cpus
, buf
);
615 * show_affected_cpus - show the CPUs affected by each transition
617 static ssize_t
show_affected_cpus(struct cpufreq_policy
*policy
, char *buf
)
619 return show_cpus(policy
->cpus
, buf
);
622 static ssize_t
store_scaling_setspeed(struct cpufreq_policy
*policy
,
623 const char *buf
, size_t count
)
625 unsigned int freq
= 0;
628 if (!policy
->governor
|| !policy
->governor
->store_setspeed
)
631 ret
= sscanf(buf
, "%u", &freq
);
635 policy
->governor
->store_setspeed(policy
, freq
);
640 static ssize_t
show_scaling_setspeed(struct cpufreq_policy
*policy
, char *buf
)
642 if (!policy
->governor
|| !policy
->governor
->show_setspeed
)
643 return sprintf(buf
, "<unsupported>\n");
645 return policy
->governor
->show_setspeed(policy
, buf
);
648 #define define_one_ro(_name) \
649 static struct freq_attr _name = \
650 __ATTR(_name, 0444, show_##_name, NULL)
652 #define define_one_ro0400(_name) \
653 static struct freq_attr _name = \
654 __ATTR(_name, 0400, show_##_name, NULL)
656 #define define_one_rw(_name) \
657 static struct freq_attr _name = \
658 __ATTR(_name, 0644, show_##_name, store_##_name)
660 define_one_ro0400(cpuinfo_cur_freq
);
661 define_one_ro(cpuinfo_min_freq
);
662 define_one_ro(cpuinfo_max_freq
);
663 define_one_ro(cpuinfo_transition_latency
);
664 define_one_ro(scaling_available_governors
);
665 define_one_ro(scaling_driver
);
666 define_one_ro(scaling_cur_freq
);
667 define_one_ro(related_cpus
);
668 define_one_ro(affected_cpus
);
669 define_one_rw(scaling_min_freq
);
670 define_one_rw(scaling_max_freq
);
671 define_one_rw(scaling_governor
);
672 define_one_rw(scaling_setspeed
);
674 static struct attribute
*default_attrs
[] = {
675 &cpuinfo_min_freq
.attr
,
676 &cpuinfo_max_freq
.attr
,
677 &cpuinfo_transition_latency
.attr
,
678 &scaling_min_freq
.attr
,
679 &scaling_max_freq
.attr
,
682 &scaling_governor
.attr
,
683 &scaling_driver
.attr
,
684 &scaling_available_governors
.attr
,
685 &scaling_setspeed
.attr
,
689 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
690 #define to_attr(a) container_of(a, struct freq_attr, attr)
692 static ssize_t
show(struct kobject
*kobj
, struct attribute
*attr
, char *buf
)
694 struct cpufreq_policy
*policy
= to_policy(kobj
);
695 struct freq_attr
*fattr
= to_attr(attr
);
696 ssize_t ret
= -EINVAL
;
697 policy
= cpufreq_cpu_get(policy
->cpu
);
701 if (lock_policy_rwsem_read(policy
->cpu
) < 0)
705 ret
= fattr
->show(policy
, buf
);
709 unlock_policy_rwsem_read(policy
->cpu
);
711 cpufreq_cpu_put(policy
);
716 static ssize_t
store(struct kobject
*kobj
, struct attribute
*attr
,
717 const char *buf
, size_t count
)
719 struct cpufreq_policy
*policy
= to_policy(kobj
);
720 struct freq_attr
*fattr
= to_attr(attr
);
721 ssize_t ret
= -EINVAL
;
722 policy
= cpufreq_cpu_get(policy
->cpu
);
726 if (lock_policy_rwsem_write(policy
->cpu
) < 0)
730 ret
= fattr
->store(policy
, buf
, count
);
734 unlock_policy_rwsem_write(policy
->cpu
);
736 cpufreq_cpu_put(policy
);
741 static void cpufreq_sysfs_release(struct kobject
*kobj
)
743 struct cpufreq_policy
*policy
= to_policy(kobj
);
744 dprintk("last reference is dropped\n");
745 complete(&policy
->kobj_unregister
);
748 static struct sysfs_ops sysfs_ops
= {
753 static struct kobj_type ktype_cpufreq
= {
754 .sysfs_ops
= &sysfs_ops
,
755 .default_attrs
= default_attrs
,
756 .release
= cpufreq_sysfs_release
,
761 * cpufreq_add_dev - add a CPU device
763 * Adds the cpufreq interface for a CPU device.
765 * The Oracle says: try running cpufreq registration/unregistration concurrently
766 * with with cpu hotplugging and all hell will break loose. Tried to clean this
767 * mess up, but more thorough testing is needed. - Mathieu
769 static int cpufreq_add_dev(struct sys_device
*sys_dev
)
771 unsigned int cpu
= sys_dev
->id
;
773 struct cpufreq_policy new_policy
;
774 struct cpufreq_policy
*policy
;
775 struct freq_attr
**drv_attr
;
776 struct sys_device
*cpu_sys_dev
;
780 struct cpufreq_policy
*managed_policy
;
783 if (cpu_is_offline(cpu
))
786 cpufreq_debug_disable_ratelimit();
787 dprintk("adding CPU %u\n", cpu
);
790 /* check whether a different CPU already registered this
791 * CPU because it is in the same boat. */
792 policy
= cpufreq_cpu_get(cpu
);
793 if (unlikely(policy
)) {
794 cpufreq_cpu_put(policy
);
795 cpufreq_debug_enable_ratelimit();
800 if (!try_module_get(cpufreq_driver
->owner
)) {
805 policy
= kzalloc(sizeof(struct cpufreq_policy
), GFP_KERNEL
);
810 if (!alloc_cpumask_var(&policy
->cpus
, GFP_KERNEL
)) {
812 goto err_free_policy
;
814 if (!zalloc_cpumask_var(&policy
->related_cpus
, GFP_KERNEL
)) {
816 goto err_free_cpumask
;
820 cpumask_copy(policy
->cpus
, cpumask_of(cpu
));
822 /* Initially set CPU itself as the policy_cpu */
823 per_cpu(policy_cpu
, cpu
) = cpu
;
824 ret
= (lock_policy_rwsem_write(cpu
) < 0);
827 init_completion(&policy
->kobj_unregister
);
828 INIT_WORK(&policy
->update
, handle_update
);
830 /* Set governor before ->init, so that driver could check it */
831 policy
->governor
= CPUFREQ_DEFAULT_GOVERNOR
;
832 /* call driver. From then on the cpufreq must be able
833 * to accept all calls to ->verify and ->setpolicy for this CPU
835 ret
= cpufreq_driver
->init(policy
);
837 dprintk("initialization failed\n");
838 goto err_unlock_policy
;
840 policy
->user_policy
.min
= policy
->min
;
841 policy
->user_policy
.max
= policy
->max
;
843 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
844 CPUFREQ_START
, policy
);
848 #ifdef CONFIG_HOTPLUG_CPU
849 if (per_cpu(cpufreq_cpu_governor
, cpu
)) {
850 policy
->governor
= per_cpu(cpufreq_cpu_governor
, cpu
);
851 dprintk("Restoring governor %s for cpu %d\n",
852 policy
->governor
->name
, cpu
);
856 for_each_cpu(j
, policy
->cpus
) {
860 /* Check for existing affected CPUs.
861 * They may not be aware of it due to CPU Hotplug.
863 managed_policy
= cpufreq_cpu_get(j
);
864 if (unlikely(managed_policy
)) {
866 /* Set proper policy_cpu */
867 unlock_policy_rwsem_write(cpu
);
868 per_cpu(policy_cpu
, cpu
) = managed_policy
->cpu
;
870 if (lock_policy_rwsem_write(cpu
) < 0) {
871 /* Should not go through policy unlock path */
872 if (cpufreq_driver
->exit
)
873 cpufreq_driver
->exit(policy
);
875 cpufreq_cpu_put(managed_policy
);
876 goto err_free_cpumask
;
879 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
880 cpumask_copy(managed_policy
->cpus
, policy
->cpus
);
881 per_cpu(cpufreq_cpu_data
, cpu
) = managed_policy
;
882 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
884 dprintk("CPU already managed, adding link\n");
885 ret
= sysfs_create_link(&sys_dev
->kobj
,
886 &managed_policy
->kobj
,
889 cpufreq_cpu_put(managed_policy
);
891 * Success. We only needed to be added to the mask.
892 * Call driver->exit() because only the cpu parent of
893 * the kobj needed to call init().
895 goto out_driver_exit
; /* call driver->exit() */
899 memcpy(&new_policy
, policy
, sizeof(struct cpufreq_policy
));
901 /* prepare interface data */
902 ret
= kobject_init_and_add(&policy
->kobj
, &ktype_cpufreq
, &sys_dev
->kobj
,
905 goto out_driver_exit
;
907 /* set up files for this cpu device */
908 drv_attr
= cpufreq_driver
->attr
;
909 while ((drv_attr
) && (*drv_attr
)) {
910 ret
= sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
912 goto err_out_kobj_put
;
915 if (cpufreq_driver
->get
) {
916 ret
= sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
918 goto err_out_kobj_put
;
920 if (cpufreq_driver
->target
) {
921 ret
= sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
923 goto err_out_kobj_put
;
926 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
927 for_each_cpu(j
, policy
->cpus
) {
928 per_cpu(cpufreq_cpu_data
, j
) = policy
;
929 per_cpu(policy_cpu
, j
) = policy
->cpu
;
931 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
933 /* symlink affected CPUs */
934 for_each_cpu(j
, policy
->cpus
) {
940 dprintk("CPU %u already managed, adding link\n", j
);
941 managed_policy
= cpufreq_cpu_get(cpu
);
942 cpu_sys_dev
= get_cpu_sysdev(j
);
943 ret
= sysfs_create_link(&cpu_sys_dev
->kobj
, &policy
->kobj
,
946 cpufreq_cpu_put(managed_policy
);
947 goto err_out_unregister
;
951 policy
->governor
= NULL
; /* to assure that the starting sequence is
952 * run in cpufreq_set_policy */
954 /* set default policy */
955 ret
= __cpufreq_set_policy(policy
, &new_policy
);
956 policy
->user_policy
.policy
= policy
->policy
;
957 policy
->user_policy
.governor
= policy
->governor
;
960 dprintk("setting policy failed\n");
961 goto err_out_unregister
;
964 unlock_policy_rwsem_write(cpu
);
966 kobject_uevent(&policy
->kobj
, KOBJ_ADD
);
967 module_put(cpufreq_driver
->owner
);
968 dprintk("initialization complete\n");
969 cpufreq_debug_enable_ratelimit();
975 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
976 for_each_cpu(j
, policy
->cpus
)
977 per_cpu(cpufreq_cpu_data
, j
) = NULL
;
978 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
981 kobject_put(&policy
->kobj
);
982 wait_for_completion(&policy
->kobj_unregister
);
985 if (cpufreq_driver
->exit
)
986 cpufreq_driver
->exit(policy
);
989 unlock_policy_rwsem_write(cpu
);
991 free_cpumask_var(policy
->cpus
);
995 module_put(cpufreq_driver
->owner
);
997 cpufreq_debug_enable_ratelimit();
1003 * __cpufreq_remove_dev - remove a CPU device
1005 * Removes the cpufreq interface for a CPU device.
1006 * Caller should already have policy_rwsem in write mode for this CPU.
1007 * This routine frees the rwsem before returning.
1009 static int __cpufreq_remove_dev(struct sys_device
*sys_dev
)
1011 unsigned int cpu
= sys_dev
->id
;
1012 unsigned long flags
;
1013 struct cpufreq_policy
*data
;
1015 struct sys_device
*cpu_sys_dev
;
1019 cpufreq_debug_disable_ratelimit();
1020 dprintk("unregistering CPU %u\n", cpu
);
1022 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1023 data
= per_cpu(cpufreq_cpu_data
, cpu
);
1026 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1027 cpufreq_debug_enable_ratelimit();
1028 unlock_policy_rwsem_write(cpu
);
1031 per_cpu(cpufreq_cpu_data
, cpu
) = NULL
;
1035 /* if this isn't the CPU which is the parent of the kobj, we
1036 * only need to unlink, put and exit
1038 if (unlikely(cpu
!= data
->cpu
)) {
1039 dprintk("removing link\n");
1040 cpumask_clear_cpu(cpu
, data
->cpus
);
1041 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1042 sysfs_remove_link(&sys_dev
->kobj
, "cpufreq");
1043 cpufreq_cpu_put(data
);
1044 cpufreq_debug_enable_ratelimit();
1045 unlock_policy_rwsem_write(cpu
);
1052 #ifdef CONFIG_HOTPLUG_CPU
1053 per_cpu(cpufreq_cpu_governor
, cpu
) = data
->governor
;
1056 /* if we have other CPUs still registered, we need to unlink them,
1057 * or else wait_for_completion below will lock up. Clean the
1058 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1059 * the sysfs links afterwards.
1061 if (unlikely(cpumask_weight(data
->cpus
) > 1)) {
1062 for_each_cpu(j
, data
->cpus
) {
1065 per_cpu(cpufreq_cpu_data
, j
) = NULL
;
1069 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1071 if (unlikely(cpumask_weight(data
->cpus
) > 1)) {
1072 for_each_cpu(j
, data
->cpus
) {
1075 dprintk("removing link for cpu %u\n", j
);
1076 #ifdef CONFIG_HOTPLUG_CPU
1077 per_cpu(cpufreq_cpu_governor
, j
) = data
->governor
;
1079 cpu_sys_dev
= get_cpu_sysdev(j
);
1080 sysfs_remove_link(&cpu_sys_dev
->kobj
, "cpufreq");
1081 cpufreq_cpu_put(data
);
1085 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1088 if (cpufreq_driver
->target
)
1089 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
1091 kobject_put(&data
->kobj
);
1093 /* we need to make sure that the underlying kobj is actually
1094 * not referenced anymore by anybody before we proceed with
1097 dprintk("waiting for dropping of refcount\n");
1098 wait_for_completion(&data
->kobj_unregister
);
1099 dprintk("wait complete\n");
1101 if (cpufreq_driver
->exit
)
1102 cpufreq_driver
->exit(data
);
1104 unlock_policy_rwsem_write(cpu
);
1106 free_cpumask_var(data
->related_cpus
);
1107 free_cpumask_var(data
->cpus
);
1109 per_cpu(cpufreq_cpu_data
, cpu
) = NULL
;
1111 cpufreq_debug_enable_ratelimit();
1116 static int cpufreq_remove_dev(struct sys_device
*sys_dev
)
1118 unsigned int cpu
= sys_dev
->id
;
1121 if (cpu_is_offline(cpu
))
1124 if (unlikely(lock_policy_rwsem_write(cpu
)))
1127 retval
= __cpufreq_remove_dev(sys_dev
);
1132 static void handle_update(struct work_struct
*work
)
1134 struct cpufreq_policy
*policy
=
1135 container_of(work
, struct cpufreq_policy
, update
);
1136 unsigned int cpu
= policy
->cpu
;
1137 dprintk("handle_update for cpu %u called\n", cpu
);
1138 cpufreq_update_policy(cpu
);
1142 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1144 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1145 * @new_freq: CPU frequency the CPU actually runs at
1147 * We adjust to current frequency first, and need to clean up later.
1148 * So either call to cpufreq_update_policy() or schedule handle_update()).
1150 static void cpufreq_out_of_sync(unsigned int cpu
, unsigned int old_freq
,
1151 unsigned int new_freq
)
1153 struct cpufreq_freqs freqs
;
1155 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1156 "core thinks of %u, is %u kHz.\n", old_freq
, new_freq
);
1159 freqs
.old
= old_freq
;
1160 freqs
.new = new_freq
;
1161 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
1162 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
1167 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1170 * This is the last known freq, without actually getting it from the driver.
1171 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1173 unsigned int cpufreq_quick_get(unsigned int cpu
)
1175 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1176 unsigned int ret_freq
= 0;
1179 ret_freq
= policy
->cur
;
1180 cpufreq_cpu_put(policy
);
1185 EXPORT_SYMBOL(cpufreq_quick_get
);
1188 static unsigned int __cpufreq_get(unsigned int cpu
)
1190 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1191 unsigned int ret_freq
= 0;
1193 if (!cpufreq_driver
->get
)
1196 ret_freq
= cpufreq_driver
->get(cpu
);
1198 if (ret_freq
&& policy
->cur
&&
1199 !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1200 /* verify no discrepancy between actual and
1201 saved value exists */
1202 if (unlikely(ret_freq
!= policy
->cur
)) {
1203 cpufreq_out_of_sync(cpu
, policy
->cur
, ret_freq
);
1204 schedule_work(&policy
->update
);
1212 * cpufreq_get - get the current CPU frequency (in kHz)
1215 * Get the CPU current (static) CPU frequency
1217 unsigned int cpufreq_get(unsigned int cpu
)
1219 unsigned int ret_freq
= 0;
1220 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1225 if (unlikely(lock_policy_rwsem_read(cpu
)))
1228 ret_freq
= __cpufreq_get(cpu
);
1230 unlock_policy_rwsem_read(cpu
);
1233 cpufreq_cpu_put(policy
);
1237 EXPORT_SYMBOL(cpufreq_get
);
1241 * cpufreq_suspend - let the low level driver prepare for suspend
1244 static int cpufreq_suspend(struct sys_device
*sysdev
, pm_message_t pmsg
)
1246 int cpu
= sysdev
->id
;
1248 unsigned int cur_freq
= 0;
1249 struct cpufreq_policy
*cpu_policy
;
1251 dprintk("suspending cpu %u\n", cpu
);
1253 if (!cpu_online(cpu
))
1256 /* we may be lax here as interrupts are off. Nonetheless
1257 * we need to grab the correct cpu policy, as to check
1258 * whether we really run on this CPU.
1261 cpu_policy
= cpufreq_cpu_get(cpu
);
1265 /* only handle each CPU group once */
1266 if (unlikely(cpu_policy
->cpu
!= cpu
))
1269 if (cpufreq_driver
->suspend
) {
1270 ret
= cpufreq_driver
->suspend(cpu_policy
, pmsg
);
1272 printk(KERN_ERR
"cpufreq: suspend failed in ->suspend "
1273 "step on CPU %u\n", cpu_policy
->cpu
);
1278 if (cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)
1281 if (cpufreq_driver
->get
)
1282 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1284 if (!cur_freq
|| !cpu_policy
->cur
) {
1285 printk(KERN_ERR
"cpufreq: suspend failed to assert current "
1286 "frequency is what timing core thinks it is.\n");
1290 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1291 struct cpufreq_freqs freqs
;
1293 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1294 dprintk("Warning: CPU frequency is %u, "
1295 "cpufreq assumed %u kHz.\n",
1296 cur_freq
, cpu_policy
->cur
);
1299 freqs
.old
= cpu_policy
->cur
;
1300 freqs
.new = cur_freq
;
1302 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
1303 CPUFREQ_SUSPENDCHANGE
, &freqs
);
1304 adjust_jiffies(CPUFREQ_SUSPENDCHANGE
, &freqs
);
1306 cpu_policy
->cur
= cur_freq
;
1310 cpufreq_cpu_put(cpu_policy
);
1315 * cpufreq_resume - restore proper CPU frequency handling after resume
1317 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1318 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1319 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1322 static int cpufreq_resume(struct sys_device
*sysdev
)
1324 int cpu
= sysdev
->id
;
1326 struct cpufreq_policy
*cpu_policy
;
1328 dprintk("resuming cpu %u\n", cpu
);
1330 if (!cpu_online(cpu
))
1333 /* we may be lax here as interrupts are off. Nonetheless
1334 * we need to grab the correct cpu policy, as to check
1335 * whether we really run on this CPU.
1338 cpu_policy
= cpufreq_cpu_get(cpu
);
1342 /* only handle each CPU group once */
1343 if (unlikely(cpu_policy
->cpu
!= cpu
))
1346 if (cpufreq_driver
->resume
) {
1347 ret
= cpufreq_driver
->resume(cpu_policy
);
1349 printk(KERN_ERR
"cpufreq: resume failed in ->resume "
1350 "step on CPU %u\n", cpu_policy
->cpu
);
1355 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1356 unsigned int cur_freq
= 0;
1358 if (cpufreq_driver
->get
)
1359 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1361 if (!cur_freq
|| !cpu_policy
->cur
) {
1362 printk(KERN_ERR
"cpufreq: resume failed to assert "
1363 "current frequency is what timing core "
1368 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1369 struct cpufreq_freqs freqs
;
1371 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1372 dprintk("Warning: CPU frequency "
1373 "is %u, cpufreq assumed %u kHz.\n",
1374 cur_freq
, cpu_policy
->cur
);
1377 freqs
.old
= cpu_policy
->cur
;
1378 freqs
.new = cur_freq
;
1380 srcu_notifier_call_chain(
1381 &cpufreq_transition_notifier_list
,
1382 CPUFREQ_RESUMECHANGE
, &freqs
);
1383 adjust_jiffies(CPUFREQ_RESUMECHANGE
, &freqs
);
1385 cpu_policy
->cur
= cur_freq
;
1390 schedule_work(&cpu_policy
->update
);
1392 cpufreq_cpu_put(cpu_policy
);
1396 static struct sysdev_driver cpufreq_sysdev_driver
= {
1397 .add
= cpufreq_add_dev
,
1398 .remove
= cpufreq_remove_dev
,
1399 .suspend
= cpufreq_suspend
,
1400 .resume
= cpufreq_resume
,
1404 /*********************************************************************
1405 * NOTIFIER LISTS INTERFACE *
1406 *********************************************************************/
1409 * cpufreq_register_notifier - register a driver with cpufreq
1410 * @nb: notifier function to register
1411 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1413 * Add a driver to one of two lists: either a list of drivers that
1414 * are notified about clock rate changes (once before and once after
1415 * the transition), or a list of drivers that are notified about
1416 * changes in cpufreq policy.
1418 * This function may sleep, and has the same return conditions as
1419 * blocking_notifier_chain_register.
1421 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1425 WARN_ON(!init_cpufreq_transition_notifier_list_called
);
1428 case CPUFREQ_TRANSITION_NOTIFIER
:
1429 ret
= srcu_notifier_chain_register(
1430 &cpufreq_transition_notifier_list
, nb
);
1432 case CPUFREQ_POLICY_NOTIFIER
:
1433 ret
= blocking_notifier_chain_register(
1434 &cpufreq_policy_notifier_list
, nb
);
1442 EXPORT_SYMBOL(cpufreq_register_notifier
);
1446 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1447 * @nb: notifier block to be unregistered
1448 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1450 * Remove a driver from the CPU frequency notifier list.
1452 * This function may sleep, and has the same return conditions as
1453 * blocking_notifier_chain_unregister.
1455 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1460 case CPUFREQ_TRANSITION_NOTIFIER
:
1461 ret
= srcu_notifier_chain_unregister(
1462 &cpufreq_transition_notifier_list
, nb
);
1464 case CPUFREQ_POLICY_NOTIFIER
:
1465 ret
= blocking_notifier_chain_unregister(
1466 &cpufreq_policy_notifier_list
, nb
);
1474 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1477 /*********************************************************************
1479 *********************************************************************/
1482 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1483 unsigned int target_freq
,
1484 unsigned int relation
)
1486 int retval
= -EINVAL
;
1488 dprintk("target for CPU %u: %u kHz, relation %u\n", policy
->cpu
,
1489 target_freq
, relation
);
1490 if (cpu_online(policy
->cpu
) && cpufreq_driver
->target
)
1491 retval
= cpufreq_driver
->target(policy
, target_freq
, relation
);
1495 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1497 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1498 unsigned int target_freq
,
1499 unsigned int relation
)
1503 policy
= cpufreq_cpu_get(policy
->cpu
);
1507 if (unlikely(lock_policy_rwsem_write(policy
->cpu
)))
1510 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1512 unlock_policy_rwsem_write(policy
->cpu
);
1515 cpufreq_cpu_put(policy
);
1519 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1521 int __cpufreq_driver_getavg(struct cpufreq_policy
*policy
, unsigned int cpu
)
1525 policy
= cpufreq_cpu_get(policy
->cpu
);
1529 if (cpu_online(cpu
) && cpufreq_driver
->getavg
)
1530 ret
= cpufreq_driver
->getavg(policy
, cpu
);
1532 cpufreq_cpu_put(policy
);
1535 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg
);
1538 * when "event" is CPUFREQ_GOV_LIMITS
1541 static int __cpufreq_governor(struct cpufreq_policy
*policy
,
1546 /* Only must be defined when default governor is known to have latency
1547 restrictions, like e.g. conservative or ondemand.
1548 That this is the case is already ensured in Kconfig
1550 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1551 struct cpufreq_governor
*gov
= &cpufreq_gov_performance
;
1553 struct cpufreq_governor
*gov
= NULL
;
1556 if (policy
->governor
->max_transition_latency
&&
1557 policy
->cpuinfo
.transition_latency
>
1558 policy
->governor
->max_transition_latency
) {
1562 printk(KERN_WARNING
"%s governor failed, too long"
1563 " transition latency of HW, fallback"
1564 " to %s governor\n",
1565 policy
->governor
->name
,
1567 policy
->governor
= gov
;
1571 if (!try_module_get(policy
->governor
->owner
))
1574 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1575 policy
->cpu
, event
);
1576 ret
= policy
->governor
->governor(policy
, event
);
1578 /* we keep one module reference alive for
1579 each CPU governed by this CPU */
1580 if ((event
!= CPUFREQ_GOV_START
) || ret
)
1581 module_put(policy
->governor
->owner
);
1582 if ((event
== CPUFREQ_GOV_STOP
) && !ret
)
1583 module_put(policy
->governor
->owner
);
1589 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1596 mutex_lock(&cpufreq_governor_mutex
);
1599 if (__find_governor(governor
->name
) == NULL
) {
1601 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1604 mutex_unlock(&cpufreq_governor_mutex
);
1607 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1610 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1615 mutex_lock(&cpufreq_governor_mutex
);
1616 list_del(&governor
->governor_list
);
1617 mutex_unlock(&cpufreq_governor_mutex
);
1620 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1624 /*********************************************************************
1625 * POLICY INTERFACE *
1626 *********************************************************************/
1629 * cpufreq_get_policy - get the current cpufreq_policy
1630 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1633 * Reads the current cpufreq policy.
1635 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
1637 struct cpufreq_policy
*cpu_policy
;
1641 cpu_policy
= cpufreq_cpu_get(cpu
);
1645 memcpy(policy
, cpu_policy
, sizeof(struct cpufreq_policy
));
1647 cpufreq_cpu_put(cpu_policy
);
1650 EXPORT_SYMBOL(cpufreq_get_policy
);
1654 * data : current policy.
1655 * policy : policy to be set.
1657 static int __cpufreq_set_policy(struct cpufreq_policy
*data
,
1658 struct cpufreq_policy
*policy
)
1662 cpufreq_debug_disable_ratelimit();
1663 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy
->cpu
,
1664 policy
->min
, policy
->max
);
1666 memcpy(&policy
->cpuinfo
, &data
->cpuinfo
,
1667 sizeof(struct cpufreq_cpuinfo
));
1669 if (policy
->min
> data
->max
|| policy
->max
< data
->min
) {
1674 /* verify the cpu speed can be set within this limit */
1675 ret
= cpufreq_driver
->verify(policy
);
1679 /* adjust if necessary - all reasons */
1680 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1681 CPUFREQ_ADJUST
, policy
);
1683 /* adjust if necessary - hardware incompatibility*/
1684 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1685 CPUFREQ_INCOMPATIBLE
, policy
);
1687 /* verify the cpu speed can be set within this limit,
1688 which might be different to the first one */
1689 ret
= cpufreq_driver
->verify(policy
);
1693 /* notification of the new policy */
1694 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1695 CPUFREQ_NOTIFY
, policy
);
1697 data
->min
= policy
->min
;
1698 data
->max
= policy
->max
;
1700 dprintk("new min and max freqs are %u - %u kHz\n",
1701 data
->min
, data
->max
);
1703 if (cpufreq_driver
->setpolicy
) {
1704 data
->policy
= policy
->policy
;
1705 dprintk("setting range\n");
1706 ret
= cpufreq_driver
->setpolicy(policy
);
1708 if (policy
->governor
!= data
->governor
) {
1709 /* save old, working values */
1710 struct cpufreq_governor
*old_gov
= data
->governor
;
1712 dprintk("governor switch\n");
1714 /* end old governor */
1716 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
1718 /* start new governor */
1719 data
->governor
= policy
->governor
;
1720 if (__cpufreq_governor(data
, CPUFREQ_GOV_START
)) {
1721 /* new governor failed, so re-start old one */
1722 dprintk("starting governor %s failed\n",
1723 data
->governor
->name
);
1725 data
->governor
= old_gov
;
1726 __cpufreq_governor(data
,
1732 /* might be a policy change, too, so fall through */
1734 dprintk("governor: change or update limits\n");
1735 __cpufreq_governor(data
, CPUFREQ_GOV_LIMITS
);
1739 cpufreq_debug_enable_ratelimit();
1744 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1745 * @cpu: CPU which shall be re-evaluated
1747 * Usefull for policy notifiers which have different necessities
1748 * at different times.
1750 int cpufreq_update_policy(unsigned int cpu
)
1752 struct cpufreq_policy
*data
= cpufreq_cpu_get(cpu
);
1753 struct cpufreq_policy policy
;
1761 if (unlikely(lock_policy_rwsem_write(cpu
))) {
1766 dprintk("updating policy for CPU %u\n", cpu
);
1767 memcpy(&policy
, data
, sizeof(struct cpufreq_policy
));
1768 policy
.min
= data
->user_policy
.min
;
1769 policy
.max
= data
->user_policy
.max
;
1770 policy
.policy
= data
->user_policy
.policy
;
1771 policy
.governor
= data
->user_policy
.governor
;
1773 /* BIOS might change freq behind our back
1774 -> ask driver for current freq and notify governors about a change */
1775 if (cpufreq_driver
->get
) {
1776 policy
.cur
= cpufreq_driver
->get(cpu
);
1778 dprintk("Driver did not initialize current freq");
1779 data
->cur
= policy
.cur
;
1781 if (data
->cur
!= policy
.cur
)
1782 cpufreq_out_of_sync(cpu
, data
->cur
,
1787 ret
= __cpufreq_set_policy(data
, &policy
);
1789 unlock_policy_rwsem_write(cpu
);
1792 cpufreq_cpu_put(data
);
1796 EXPORT_SYMBOL(cpufreq_update_policy
);
1798 static int __cpuinit
cpufreq_cpu_callback(struct notifier_block
*nfb
,
1799 unsigned long action
, void *hcpu
)
1801 unsigned int cpu
= (unsigned long)hcpu
;
1802 struct sys_device
*sys_dev
;
1804 sys_dev
= get_cpu_sysdev(cpu
);
1808 case CPU_ONLINE_FROZEN
:
1809 cpufreq_add_dev(sys_dev
);
1811 case CPU_DOWN_PREPARE
:
1812 case CPU_DOWN_PREPARE_FROZEN
:
1813 if (unlikely(lock_policy_rwsem_write(cpu
)))
1816 __cpufreq_remove_dev(sys_dev
);
1818 case CPU_DOWN_FAILED
:
1819 case CPU_DOWN_FAILED_FROZEN
:
1820 cpufreq_add_dev(sys_dev
);
1827 static struct notifier_block __refdata cpufreq_cpu_notifier
=
1829 .notifier_call
= cpufreq_cpu_callback
,
1832 /*********************************************************************
1833 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1834 *********************************************************************/
1837 * cpufreq_register_driver - register a CPU Frequency driver
1838 * @driver_data: A struct cpufreq_driver containing the values#
1839 * submitted by the CPU Frequency driver.
1841 * Registers a CPU Frequency driver to this core code. This code
1842 * returns zero on success, -EBUSY when another driver got here first
1843 * (and isn't unregistered in the meantime).
1846 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
1848 unsigned long flags
;
1851 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
1852 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
1855 dprintk("trying to register driver %s\n", driver_data
->name
);
1857 if (driver_data
->setpolicy
)
1858 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
1860 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1861 if (cpufreq_driver
) {
1862 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1865 cpufreq_driver
= driver_data
;
1866 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1868 ret
= sysdev_driver_register(&cpu_sysdev_class
,
1869 &cpufreq_sysdev_driver
);
1871 if ((!ret
) && !(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
1875 /* check for at least one working CPU */
1876 for (i
= 0; i
< nr_cpu_ids
; i
++)
1877 if (cpu_possible(i
) && per_cpu(cpufreq_cpu_data
, i
)) {
1882 /* if all ->init() calls failed, unregister */
1884 dprintk("no CPU initialized for driver %s\n",
1886 sysdev_driver_unregister(&cpu_sysdev_class
,
1887 &cpufreq_sysdev_driver
);
1889 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1890 cpufreq_driver
= NULL
;
1891 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1896 register_hotcpu_notifier(&cpufreq_cpu_notifier
);
1897 dprintk("driver %s up and running\n", driver_data
->name
);
1898 cpufreq_debug_enable_ratelimit();
1903 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
1907 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1909 * Unregister the current CPUFreq driver. Only call this if you have
1910 * the right to do so, i.e. if you have succeeded in initialising before!
1911 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1912 * currently not initialised.
1914 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
1916 unsigned long flags
;
1918 cpufreq_debug_disable_ratelimit();
1920 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
)) {
1921 cpufreq_debug_enable_ratelimit();
1925 dprintk("unregistering driver %s\n", driver
->name
);
1927 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1928 unregister_hotcpu_notifier(&cpufreq_cpu_notifier
);
1930 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1931 cpufreq_driver
= NULL
;
1932 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1936 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);
1938 static int __init
cpufreq_core_init(void)
1942 for_each_possible_cpu(cpu
) {
1943 per_cpu(policy_cpu
, cpu
) = -1;
1944 init_rwsem(&per_cpu(cpu_policy_rwsem
, cpu
));
1949 core_initcall(cpufreq_core_init
);