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, "cpufreq-core", msg)
35 * The "cpufreq driver" - the arch- or hardware-dependent low
36 * level driver of CPUFreq support, and its spinlock. This lock
37 * also protects the cpufreq_cpu_data array.
39 static struct cpufreq_driver
*cpufreq_driver
;
40 static struct cpufreq_policy
*cpufreq_cpu_data
[NR_CPUS
];
41 static DEFINE_SPINLOCK(cpufreq_driver_lock
);
43 /* internal prototypes */
44 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
);
45 static void handle_update(void *data
);
48 * Two notifier lists: the "policy" list is involved in the
49 * validation process for a new CPU frequency policy; the
50 * "transition" list for kernel code that needs to handle
51 * changes to devices when the CPU clock speed changes.
52 * The mutex locks both lists.
54 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list
);
55 static struct srcu_notifier_head cpufreq_transition_notifier_list
;
57 static int __init
init_cpufreq_transition_notifier_list(void)
59 srcu_init_notifier_head(&cpufreq_transition_notifier_list
);
62 core_initcall(init_cpufreq_transition_notifier_list
);
64 static LIST_HEAD(cpufreq_governor_list
);
65 static DEFINE_MUTEX (cpufreq_governor_mutex
);
67 struct cpufreq_policy
*cpufreq_cpu_get(unsigned int cpu
)
69 struct cpufreq_policy
*data
;
75 /* get the cpufreq driver */
76 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
81 if (!try_module_get(cpufreq_driver
->owner
))
86 data
= cpufreq_cpu_data
[cpu
];
89 goto err_out_put_module
;
91 if (!kobject_get(&data
->kobj
))
92 goto err_out_put_module
;
94 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
98 module_put(cpufreq_driver
->owner
);
100 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
104 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
107 void cpufreq_cpu_put(struct cpufreq_policy
*data
)
109 kobject_put(&data
->kobj
);
110 module_put(cpufreq_driver
->owner
);
112 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
115 /*********************************************************************
116 * UNIFIED DEBUG HELPERS *
117 *********************************************************************/
118 #ifdef CONFIG_CPU_FREQ_DEBUG
120 /* what part(s) of the CPUfreq subsystem are debugged? */
121 static unsigned int debug
;
123 /* is the debug output ratelimit'ed using printk_ratelimit? User can
124 * set or modify this value.
126 static unsigned int debug_ratelimit
= 1;
128 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
129 * loading of a cpufreq driver, temporarily disabled when a new policy
130 * is set, and disabled upon cpufreq driver removal
132 static unsigned int disable_ratelimit
= 1;
133 static DEFINE_SPINLOCK(disable_ratelimit_lock
);
135 static void cpufreq_debug_enable_ratelimit(void)
139 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
140 if (disable_ratelimit
)
142 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
145 static void cpufreq_debug_disable_ratelimit(void)
149 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
151 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
154 void cpufreq_debug_printk(unsigned int type
, const char *prefix
, const char *fmt
, ...)
163 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
164 if (!disable_ratelimit
&& debug_ratelimit
&& !printk_ratelimit()) {
165 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
168 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
170 len
= snprintf(s
, 256, KERN_DEBUG
"%s: ", prefix
);
173 len
+= vsnprintf(&s
[len
], (256 - len
), fmt
, args
);
181 EXPORT_SYMBOL(cpufreq_debug_printk
);
184 module_param(debug
, uint
, 0644);
185 MODULE_PARM_DESC(debug
, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
187 module_param(debug_ratelimit
, uint
, 0644);
188 MODULE_PARM_DESC(debug_ratelimit
, "CPUfreq debugging: set to 0 to disable ratelimiting.");
190 #else /* !CONFIG_CPU_FREQ_DEBUG */
192 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
193 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
195 #endif /* CONFIG_CPU_FREQ_DEBUG */
198 /*********************************************************************
199 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
200 *********************************************************************/
203 * adjust_jiffies - adjust the system "loops_per_jiffy"
205 * This function alters the system "loops_per_jiffy" for the clock
206 * speed change. Note that loops_per_jiffy cannot be updated on SMP
207 * systems as each CPU might be scaled differently. So, use the arch
208 * per-CPU loops_per_jiffy value wherever possible.
211 static unsigned long l_p_j_ref
;
212 static unsigned int l_p_j_ref_freq
;
214 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
216 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
219 if (!l_p_j_ref_freq
) {
220 l_p_j_ref
= loops_per_jiffy
;
221 l_p_j_ref_freq
= ci
->old
;
222 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref
, l_p_j_ref_freq
);
224 if ((val
== CPUFREQ_PRECHANGE
&& ci
->old
< ci
->new) ||
225 (val
== CPUFREQ_POSTCHANGE
&& ci
->old
> ci
->new) ||
226 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
227 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
, ci
->new);
228 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy
, ci
->new);
232 static inline void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
) { return; }
237 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
238 * on frequency transition.
240 * This function calls the transition notifiers and the "adjust_jiffies"
241 * function. It is called twice on all CPU frequency changes that have
244 void cpufreq_notify_transition(struct cpufreq_freqs
*freqs
, unsigned int state
)
246 struct cpufreq_policy
*policy
;
248 BUG_ON(irqs_disabled());
250 freqs
->flags
= cpufreq_driver
->flags
;
251 dprintk("notification %u of frequency transition to %u kHz\n",
254 policy
= cpufreq_cpu_data
[freqs
->cpu
];
257 case CPUFREQ_PRECHANGE
:
258 /* detect if the driver reported a value as "old frequency"
259 * which is not equal to what the cpufreq core thinks is
262 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
263 if ((policy
) && (policy
->cpu
== freqs
->cpu
) &&
264 (policy
->cur
) && (policy
->cur
!= freqs
->old
)) {
265 dprintk("Warning: CPU frequency is"
266 " %u, cpufreq assumed %u kHz.\n",
267 freqs
->old
, policy
->cur
);
268 freqs
->old
= policy
->cur
;
271 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
272 CPUFREQ_PRECHANGE
, freqs
);
273 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
276 case CPUFREQ_POSTCHANGE
:
277 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
278 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
279 CPUFREQ_POSTCHANGE
, freqs
);
280 if (likely(policy
) && likely(policy
->cpu
== freqs
->cpu
))
281 policy
->cur
= freqs
->new;
285 EXPORT_SYMBOL_GPL(cpufreq_notify_transition
);
289 /*********************************************************************
291 *********************************************************************/
293 static struct cpufreq_governor
*__find_governor(const char *str_governor
)
295 struct cpufreq_governor
*t
;
297 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
)
298 if (!strnicmp(str_governor
,t
->name
,CPUFREQ_NAME_LEN
))
305 * cpufreq_parse_governor - parse a governor string
307 static int cpufreq_parse_governor (char *str_governor
, unsigned int *policy
,
308 struct cpufreq_governor
**governor
)
315 if (cpufreq_driver
->setpolicy
) {
316 if (!strnicmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
317 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
319 } else if (!strnicmp(str_governor
, "powersave", CPUFREQ_NAME_LEN
)) {
320 *policy
= CPUFREQ_POLICY_POWERSAVE
;
323 } else if (cpufreq_driver
->target
) {
324 struct cpufreq_governor
*t
;
326 mutex_lock(&cpufreq_governor_mutex
);
328 t
= __find_governor(str_governor
);
331 char *name
= kasprintf(GFP_KERNEL
, "cpufreq_%s", str_governor
);
336 mutex_unlock(&cpufreq_governor_mutex
);
337 ret
= request_module(name
);
338 mutex_lock(&cpufreq_governor_mutex
);
341 t
= __find_governor(str_governor
);
352 mutex_unlock(&cpufreq_governor_mutex
);
359 /* drivers/base/cpu.c */
360 extern struct sysdev_class cpu_sysdev_class
;
364 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
366 * Write out information from cpufreq_driver->policy[cpu]; object must be
370 #define show_one(file_name, object) \
371 static ssize_t show_##file_name \
372 (struct cpufreq_policy * policy, char *buf) \
374 return sprintf (buf, "%u\n", policy->object); \
377 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
378 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
379 show_one(scaling_min_freq
, min
);
380 show_one(scaling_max_freq
, max
);
381 show_one(scaling_cur_freq
, cur
);
383 static int __cpufreq_set_policy(struct cpufreq_policy
*data
, struct cpufreq_policy
*policy
);
386 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
388 #define store_one(file_name, object) \
389 static ssize_t store_##file_name \
390 (struct cpufreq_policy * policy, const char *buf, size_t count) \
392 unsigned int ret = -EINVAL; \
393 struct cpufreq_policy new_policy; \
395 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
399 ret = sscanf (buf, "%u", &new_policy.object); \
403 lock_cpu_hotplug(); \
404 mutex_lock(&policy->lock); \
405 ret = __cpufreq_set_policy(policy, &new_policy); \
406 policy->user_policy.object = policy->object; \
407 mutex_unlock(&policy->lock); \
408 unlock_cpu_hotplug(); \
410 return ret ? ret : count; \
413 store_one(scaling_min_freq
,min
);
414 store_one(scaling_max_freq
,max
);
417 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
419 static ssize_t
show_cpuinfo_cur_freq (struct cpufreq_policy
* policy
, char *buf
)
421 unsigned int cur_freq
= cpufreq_get(policy
->cpu
);
423 return sprintf(buf
, "<unknown>");
424 return sprintf(buf
, "%u\n", cur_freq
);
429 * show_scaling_governor - show the current policy for the specified CPU
431 static ssize_t
show_scaling_governor (struct cpufreq_policy
* policy
, char *buf
)
433 if(policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
434 return sprintf(buf
, "powersave\n");
435 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
436 return sprintf(buf
, "performance\n");
437 else if (policy
->governor
)
438 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", policy
->governor
->name
);
444 * store_scaling_governor - store policy for the specified CPU
446 static ssize_t
store_scaling_governor (struct cpufreq_policy
* policy
,
447 const char *buf
, size_t count
)
449 unsigned int ret
= -EINVAL
;
450 char str_governor
[16];
451 struct cpufreq_policy new_policy
;
453 ret
= cpufreq_get_policy(&new_policy
, policy
->cpu
);
457 ret
= sscanf (buf
, "%15s", str_governor
);
461 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
, &new_policy
.governor
))
466 /* Do not use cpufreq_set_policy here or the user_policy.max
467 will be wrongly overridden */
468 mutex_lock(&policy
->lock
);
469 ret
= __cpufreq_set_policy(policy
, &new_policy
);
471 policy
->user_policy
.policy
= policy
->policy
;
472 policy
->user_policy
.governor
= policy
->governor
;
473 mutex_unlock(&policy
->lock
);
475 unlock_cpu_hotplug();
477 return ret
? ret
: count
;
481 * show_scaling_driver - show the cpufreq driver currently loaded
483 static ssize_t
show_scaling_driver (struct cpufreq_policy
* policy
, char *buf
)
485 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", cpufreq_driver
->name
);
489 * show_scaling_available_governors - show the available CPUfreq governors
491 static ssize_t
show_scaling_available_governors (struct cpufreq_policy
* policy
,
495 struct cpufreq_governor
*t
;
497 if (!cpufreq_driver
->target
) {
498 i
+= sprintf(buf
, "performance powersave");
502 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
503 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char)) - (CPUFREQ_NAME_LEN
+ 2)))
505 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_LEN
, "%s ", t
->name
);
508 i
+= sprintf(&buf
[i
], "\n");
512 * show_affected_cpus - show the CPUs affected by each transition
514 static ssize_t
show_affected_cpus (struct cpufreq_policy
* policy
, char *buf
)
519 for_each_cpu_mask(cpu
, policy
->cpus
) {
521 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
522 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
523 if (i
>= (PAGE_SIZE
- 5))
526 i
+= sprintf(&buf
[i
], "\n");
531 #define define_one_ro(_name) \
532 static struct freq_attr _name = \
533 __ATTR(_name, 0444, show_##_name, NULL)
535 #define define_one_ro0400(_name) \
536 static struct freq_attr _name = \
537 __ATTR(_name, 0400, show_##_name, NULL)
539 #define define_one_rw(_name) \
540 static struct freq_attr _name = \
541 __ATTR(_name, 0644, show_##_name, store_##_name)
543 define_one_ro0400(cpuinfo_cur_freq
);
544 define_one_ro(cpuinfo_min_freq
);
545 define_one_ro(cpuinfo_max_freq
);
546 define_one_ro(scaling_available_governors
);
547 define_one_ro(scaling_driver
);
548 define_one_ro(scaling_cur_freq
);
549 define_one_ro(affected_cpus
);
550 define_one_rw(scaling_min_freq
);
551 define_one_rw(scaling_max_freq
);
552 define_one_rw(scaling_governor
);
554 static struct attribute
* default_attrs
[] = {
555 &cpuinfo_min_freq
.attr
,
556 &cpuinfo_max_freq
.attr
,
557 &scaling_min_freq
.attr
,
558 &scaling_max_freq
.attr
,
560 &scaling_governor
.attr
,
561 &scaling_driver
.attr
,
562 &scaling_available_governors
.attr
,
566 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
567 #define to_attr(a) container_of(a,struct freq_attr,attr)
569 static ssize_t
show(struct kobject
* kobj
, struct attribute
* attr
,char * buf
)
571 struct cpufreq_policy
* policy
= to_policy(kobj
);
572 struct freq_attr
* fattr
= to_attr(attr
);
574 policy
= cpufreq_cpu_get(policy
->cpu
);
577 ret
= fattr
->show
? fattr
->show(policy
,buf
) : -EIO
;
578 cpufreq_cpu_put(policy
);
582 static ssize_t
store(struct kobject
* kobj
, struct attribute
* attr
,
583 const char * buf
, size_t count
)
585 struct cpufreq_policy
* policy
= to_policy(kobj
);
586 struct freq_attr
* fattr
= to_attr(attr
);
588 policy
= cpufreq_cpu_get(policy
->cpu
);
591 ret
= fattr
->store
? fattr
->store(policy
,buf
,count
) : -EIO
;
592 cpufreq_cpu_put(policy
);
596 static void cpufreq_sysfs_release(struct kobject
* kobj
)
598 struct cpufreq_policy
* policy
= to_policy(kobj
);
599 dprintk("last reference is dropped\n");
600 complete(&policy
->kobj_unregister
);
603 static struct sysfs_ops sysfs_ops
= {
608 static struct kobj_type ktype_cpufreq
= {
609 .sysfs_ops
= &sysfs_ops
,
610 .default_attrs
= default_attrs
,
611 .release
= cpufreq_sysfs_release
,
616 * cpufreq_add_dev - add a CPU device
618 * Adds the cpufreq interface for a CPU device.
620 static int cpufreq_add_dev (struct sys_device
* sys_dev
)
622 unsigned int cpu
= sys_dev
->id
;
624 struct cpufreq_policy new_policy
;
625 struct cpufreq_policy
*policy
;
626 struct freq_attr
**drv_attr
;
627 struct sys_device
*cpu_sys_dev
;
631 struct cpufreq_policy
*managed_policy
;
634 if (cpu_is_offline(cpu
))
637 cpufreq_debug_disable_ratelimit();
638 dprintk("adding CPU %u\n", cpu
);
641 /* check whether a different CPU already registered this
642 * CPU because it is in the same boat. */
643 policy
= cpufreq_cpu_get(cpu
);
644 if (unlikely(policy
)) {
645 cpufreq_cpu_put(policy
);
646 cpufreq_debug_enable_ratelimit();
651 if (!try_module_get(cpufreq_driver
->owner
)) {
656 policy
= kzalloc(sizeof(struct cpufreq_policy
), GFP_KERNEL
);
663 policy
->cpus
= cpumask_of_cpu(cpu
);
665 mutex_init(&policy
->lock
);
666 mutex_lock(&policy
->lock
);
667 init_completion(&policy
->kobj_unregister
);
668 INIT_WORK(&policy
->update
, handle_update
, (void *)(long)cpu
);
670 /* call driver. From then on the cpufreq must be able
671 * to accept all calls to ->verify and ->setpolicy for this CPU
673 ret
= cpufreq_driver
->init(policy
);
675 dprintk("initialization failed\n");
676 mutex_unlock(&policy
->lock
);
681 for_each_cpu_mask(j
, policy
->cpus
) {
685 /* check for existing affected CPUs. They may not be aware
686 * of it due to CPU Hotplug.
688 managed_policy
= cpufreq_cpu_get(j
);
689 if (unlikely(managed_policy
)) {
690 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
691 managed_policy
->cpus
= policy
->cpus
;
692 cpufreq_cpu_data
[cpu
] = managed_policy
;
693 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
695 dprintk("CPU already managed, adding link\n");
696 sysfs_create_link(&sys_dev
->kobj
,
697 &managed_policy
->kobj
, "cpufreq");
699 cpufreq_debug_enable_ratelimit();
700 mutex_unlock(&policy
->lock
);
702 goto err_out_driver_exit
; /* call driver->exit() */
706 memcpy(&new_policy
, policy
, sizeof(struct cpufreq_policy
));
708 /* prepare interface data */
709 policy
->kobj
.parent
= &sys_dev
->kobj
;
710 policy
->kobj
.ktype
= &ktype_cpufreq
;
711 strlcpy(policy
->kobj
.name
, "cpufreq", KOBJ_NAME_LEN
);
713 ret
= kobject_register(&policy
->kobj
);
715 mutex_unlock(&policy
->lock
);
716 goto err_out_driver_exit
;
718 /* set up files for this cpu device */
719 drv_attr
= cpufreq_driver
->attr
;
720 while ((drv_attr
) && (*drv_attr
)) {
721 sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
724 if (cpufreq_driver
->get
)
725 sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
726 if (cpufreq_driver
->target
)
727 sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
729 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
730 for_each_cpu_mask(j
, policy
->cpus
)
731 cpufreq_cpu_data
[j
] = policy
;
732 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
734 /* symlink affected CPUs */
735 for_each_cpu_mask(j
, policy
->cpus
) {
741 dprintk("CPU %u already managed, adding link\n", j
);
742 cpufreq_cpu_get(cpu
);
743 cpu_sys_dev
= get_cpu_sysdev(j
);
744 sysfs_create_link(&cpu_sys_dev
->kobj
, &policy
->kobj
,
748 policy
->governor
= NULL
; /* to assure that the starting sequence is
749 * run in cpufreq_set_policy */
750 mutex_unlock(&policy
->lock
);
752 /* set default policy */
753 ret
= cpufreq_set_policy(&new_policy
);
755 dprintk("setting policy failed\n");
756 goto err_out_unregister
;
759 module_put(cpufreq_driver
->owner
);
760 dprintk("initialization complete\n");
761 cpufreq_debug_enable_ratelimit();
767 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
768 for_each_cpu_mask(j
, policy
->cpus
)
769 cpufreq_cpu_data
[j
] = NULL
;
770 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
772 kobject_unregister(&policy
->kobj
);
773 wait_for_completion(&policy
->kobj_unregister
);
776 if (cpufreq_driver
->exit
)
777 cpufreq_driver
->exit(policy
);
783 module_put(cpufreq_driver
->owner
);
785 cpufreq_debug_enable_ratelimit();
791 * cpufreq_remove_dev - remove a CPU device
793 * Removes the cpufreq interface for a CPU device.
795 static int cpufreq_remove_dev (struct sys_device
* sys_dev
)
797 unsigned int cpu
= sys_dev
->id
;
799 struct cpufreq_policy
*data
;
801 struct sys_device
*cpu_sys_dev
;
805 cpufreq_debug_disable_ratelimit();
806 dprintk("unregistering CPU %u\n", cpu
);
808 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
809 data
= cpufreq_cpu_data
[cpu
];
812 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
813 cpufreq_debug_enable_ratelimit();
816 cpufreq_cpu_data
[cpu
] = NULL
;
820 /* if this isn't the CPU which is the parent of the kobj, we
821 * only need to unlink, put and exit
823 if (unlikely(cpu
!= data
->cpu
)) {
824 dprintk("removing link\n");
825 cpu_clear(cpu
, data
->cpus
);
826 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
827 sysfs_remove_link(&sys_dev
->kobj
, "cpufreq");
828 cpufreq_cpu_put(data
);
829 cpufreq_debug_enable_ratelimit();
835 if (!kobject_get(&data
->kobj
)) {
836 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
837 cpufreq_debug_enable_ratelimit();
842 /* if we have other CPUs still registered, we need to unlink them,
843 * or else wait_for_completion below will lock up. Clean the
844 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
847 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
848 for_each_cpu_mask(j
, data
->cpus
) {
851 cpufreq_cpu_data
[j
] = NULL
;
855 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
857 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
858 for_each_cpu_mask(j
, data
->cpus
) {
861 dprintk("removing link for cpu %u\n", j
);
862 cpu_sys_dev
= get_cpu_sysdev(j
);
863 sysfs_remove_link(&cpu_sys_dev
->kobj
, "cpufreq");
864 cpufreq_cpu_put(data
);
868 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
871 mutex_lock(&data
->lock
);
872 if (cpufreq_driver
->target
)
873 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
874 mutex_unlock(&data
->lock
);
876 kobject_unregister(&data
->kobj
);
878 kobject_put(&data
->kobj
);
880 /* we need to make sure that the underlying kobj is actually
881 * not referenced anymore by anybody before we proceed with
884 dprintk("waiting for dropping of refcount\n");
885 wait_for_completion(&data
->kobj_unregister
);
886 dprintk("wait complete\n");
888 if (cpufreq_driver
->exit
)
889 cpufreq_driver
->exit(data
);
893 cpufreq_debug_enable_ratelimit();
898 static void handle_update(void *data
)
900 unsigned int cpu
= (unsigned int)(long)data
;
901 dprintk("handle_update for cpu %u called\n", cpu
);
902 cpufreq_update_policy(cpu
);
906 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
908 * @old_freq: CPU frequency the kernel thinks the CPU runs at
909 * @new_freq: CPU frequency the CPU actually runs at
911 * We adjust to current frequency first, and need to clean up later. So either call
912 * to cpufreq_update_policy() or schedule handle_update()).
914 static void cpufreq_out_of_sync(unsigned int cpu
, unsigned int old_freq
, unsigned int new_freq
)
916 struct cpufreq_freqs freqs
;
918 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
919 "core thinks of %u, is %u kHz.\n", old_freq
, new_freq
);
922 freqs
.old
= old_freq
;
923 freqs
.new = new_freq
;
924 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
925 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
930 * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
933 * This is the last known freq, without actually getting it from the driver.
934 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
936 unsigned int cpufreq_quick_get(unsigned int cpu
)
938 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
939 unsigned int ret
= 0;
942 mutex_lock(&policy
->lock
);
944 mutex_unlock(&policy
->lock
);
945 cpufreq_cpu_put(policy
);
950 EXPORT_SYMBOL(cpufreq_quick_get
);
954 * cpufreq_get - get the current CPU frequency (in kHz)
957 * Get the CPU current (static) CPU frequency
959 unsigned int cpufreq_get(unsigned int cpu
)
961 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
962 unsigned int ret
= 0;
967 if (!cpufreq_driver
->get
)
970 mutex_lock(&policy
->lock
);
972 ret
= cpufreq_driver
->get(cpu
);
974 if (ret
&& policy
->cur
&& !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
975 /* verify no discrepancy between actual and saved value exists */
976 if (unlikely(ret
!= policy
->cur
)) {
977 cpufreq_out_of_sync(cpu
, policy
->cur
, ret
);
978 schedule_work(&policy
->update
);
982 mutex_unlock(&policy
->lock
);
985 cpufreq_cpu_put(policy
);
989 EXPORT_SYMBOL(cpufreq_get
);
993 * cpufreq_suspend - let the low level driver prepare for suspend
996 static int cpufreq_suspend(struct sys_device
* sysdev
, pm_message_t pmsg
)
998 int cpu
= sysdev
->id
;
999 unsigned int ret
= 0;
1000 unsigned int cur_freq
= 0;
1001 struct cpufreq_policy
*cpu_policy
;
1003 dprintk("suspending cpu %u\n", cpu
);
1005 if (!cpu_online(cpu
))
1008 /* we may be lax here as interrupts are off. Nonetheless
1009 * we need to grab the correct cpu policy, as to check
1010 * whether we really run on this CPU.
1013 cpu_policy
= cpufreq_cpu_get(cpu
);
1017 /* only handle each CPU group once */
1018 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
1019 cpufreq_cpu_put(cpu_policy
);
1023 if (cpufreq_driver
->suspend
) {
1024 ret
= cpufreq_driver
->suspend(cpu_policy
, pmsg
);
1026 printk(KERN_ERR
"cpufreq: suspend failed in ->suspend "
1027 "step on CPU %u\n", cpu_policy
->cpu
);
1028 cpufreq_cpu_put(cpu_policy
);
1034 if (cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)
1037 if (cpufreq_driver
->get
)
1038 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1040 if (!cur_freq
|| !cpu_policy
->cur
) {
1041 printk(KERN_ERR
"cpufreq: suspend failed to assert current "
1042 "frequency is what timing core thinks it is.\n");
1046 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1047 struct cpufreq_freqs freqs
;
1049 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1050 dprintk("Warning: CPU frequency is %u, "
1051 "cpufreq assumed %u kHz.\n",
1052 cur_freq
, cpu_policy
->cur
);
1055 freqs
.old
= cpu_policy
->cur
;
1056 freqs
.new = cur_freq
;
1058 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
1059 CPUFREQ_SUSPENDCHANGE
, &freqs
);
1060 adjust_jiffies(CPUFREQ_SUSPENDCHANGE
, &freqs
);
1062 cpu_policy
->cur
= cur_freq
;
1066 cpufreq_cpu_put(cpu_policy
);
1071 * cpufreq_resume - restore proper CPU frequency handling after resume
1073 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1074 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1075 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1078 static int cpufreq_resume(struct sys_device
* sysdev
)
1080 int cpu
= sysdev
->id
;
1081 unsigned int ret
= 0;
1082 struct cpufreq_policy
*cpu_policy
;
1084 dprintk("resuming cpu %u\n", cpu
);
1086 if (!cpu_online(cpu
))
1089 /* we may be lax here as interrupts are off. Nonetheless
1090 * we need to grab the correct cpu policy, as to check
1091 * whether we really run on this CPU.
1094 cpu_policy
= cpufreq_cpu_get(cpu
);
1098 /* only handle each CPU group once */
1099 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
1100 cpufreq_cpu_put(cpu_policy
);
1104 if (cpufreq_driver
->resume
) {
1105 ret
= cpufreq_driver
->resume(cpu_policy
);
1107 printk(KERN_ERR
"cpufreq: resume failed in ->resume "
1108 "step on CPU %u\n", cpu_policy
->cpu
);
1109 cpufreq_cpu_put(cpu_policy
);
1114 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1115 unsigned int cur_freq
= 0;
1117 if (cpufreq_driver
->get
)
1118 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1120 if (!cur_freq
|| !cpu_policy
->cur
) {
1121 printk(KERN_ERR
"cpufreq: resume failed to assert "
1122 "current frequency is what timing core "
1127 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1128 struct cpufreq_freqs freqs
;
1130 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1131 dprintk("Warning: CPU frequency"
1132 "is %u, cpufreq assumed %u kHz.\n",
1133 cur_freq
, cpu_policy
->cur
);
1136 freqs
.old
= cpu_policy
->cur
;
1137 freqs
.new = cur_freq
;
1139 srcu_notifier_call_chain(
1140 &cpufreq_transition_notifier_list
,
1141 CPUFREQ_RESUMECHANGE
, &freqs
);
1142 adjust_jiffies(CPUFREQ_RESUMECHANGE
, &freqs
);
1144 cpu_policy
->cur
= cur_freq
;
1149 schedule_work(&cpu_policy
->update
);
1150 cpufreq_cpu_put(cpu_policy
);
1154 static struct sysdev_driver cpufreq_sysdev_driver
= {
1155 .add
= cpufreq_add_dev
,
1156 .remove
= cpufreq_remove_dev
,
1157 .suspend
= cpufreq_suspend
,
1158 .resume
= cpufreq_resume
,
1162 /*********************************************************************
1163 * NOTIFIER LISTS INTERFACE *
1164 *********************************************************************/
1167 * cpufreq_register_notifier - register a driver with cpufreq
1168 * @nb: notifier function to register
1169 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1171 * Add a driver to one of two lists: either a list of drivers that
1172 * are notified about clock rate changes (once before and once after
1173 * the transition), or a list of drivers that are notified about
1174 * changes in cpufreq policy.
1176 * This function may sleep, and has the same return conditions as
1177 * blocking_notifier_chain_register.
1179 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1184 case CPUFREQ_TRANSITION_NOTIFIER
:
1185 ret
= srcu_notifier_chain_register(
1186 &cpufreq_transition_notifier_list
, nb
);
1188 case CPUFREQ_POLICY_NOTIFIER
:
1189 ret
= blocking_notifier_chain_register(
1190 &cpufreq_policy_notifier_list
, nb
);
1198 EXPORT_SYMBOL(cpufreq_register_notifier
);
1202 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1203 * @nb: notifier block to be unregistered
1204 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1206 * Remove a driver from the CPU frequency notifier list.
1208 * This function may sleep, and has the same return conditions as
1209 * blocking_notifier_chain_unregister.
1211 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1216 case CPUFREQ_TRANSITION_NOTIFIER
:
1217 ret
= srcu_notifier_chain_unregister(
1218 &cpufreq_transition_notifier_list
, nb
);
1220 case CPUFREQ_POLICY_NOTIFIER
:
1221 ret
= blocking_notifier_chain_unregister(
1222 &cpufreq_policy_notifier_list
, nb
);
1230 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1233 /*********************************************************************
1235 *********************************************************************/
1238 /* Must be called with lock_cpu_hotplug held */
1239 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1240 unsigned int target_freq
,
1241 unsigned int relation
)
1243 int retval
= -EINVAL
;
1245 dprintk("target for CPU %u: %u kHz, relation %u\n", policy
->cpu
,
1246 target_freq
, relation
);
1247 if (cpu_online(policy
->cpu
) && cpufreq_driver
->target
)
1248 retval
= cpufreq_driver
->target(policy
, target_freq
, relation
);
1252 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1254 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1255 unsigned int target_freq
,
1256 unsigned int relation
)
1260 policy
= cpufreq_cpu_get(policy
->cpu
);
1265 mutex_lock(&policy
->lock
);
1267 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1269 mutex_unlock(&policy
->lock
);
1270 unlock_cpu_hotplug();
1272 cpufreq_cpu_put(policy
);
1275 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1278 * Locking: Must be called with the lock_cpu_hotplug() lock held
1279 * when "event" is CPUFREQ_GOV_LIMITS
1282 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
)
1286 if (!try_module_get(policy
->governor
->owner
))
1289 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy
->cpu
, event
);
1290 ret
= policy
->governor
->governor(policy
, event
);
1292 /* we keep one module reference alive for each CPU governed by this CPU */
1293 if ((event
!= CPUFREQ_GOV_START
) || ret
)
1294 module_put(policy
->governor
->owner
);
1295 if ((event
== CPUFREQ_GOV_STOP
) && !ret
)
1296 module_put(policy
->governor
->owner
);
1302 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1309 mutex_lock(&cpufreq_governor_mutex
);
1312 if (__find_governor(governor
->name
) == NULL
) {
1314 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1317 mutex_unlock(&cpufreq_governor_mutex
);
1320 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1323 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1328 mutex_lock(&cpufreq_governor_mutex
);
1329 list_del(&governor
->governor_list
);
1330 mutex_unlock(&cpufreq_governor_mutex
);
1333 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1337 /*********************************************************************
1338 * POLICY INTERFACE *
1339 *********************************************************************/
1342 * cpufreq_get_policy - get the current cpufreq_policy
1343 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1345 * Reads the current cpufreq policy.
1347 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
1349 struct cpufreq_policy
*cpu_policy
;
1353 cpu_policy
= cpufreq_cpu_get(cpu
);
1357 mutex_lock(&cpu_policy
->lock
);
1358 memcpy(policy
, cpu_policy
, sizeof(struct cpufreq_policy
));
1359 mutex_unlock(&cpu_policy
->lock
);
1361 cpufreq_cpu_put(cpu_policy
);
1364 EXPORT_SYMBOL(cpufreq_get_policy
);
1368 * Locking: Must be called with the lock_cpu_hotplug() lock held
1370 static int __cpufreq_set_policy(struct cpufreq_policy
*data
, struct cpufreq_policy
*policy
)
1374 cpufreq_debug_disable_ratelimit();
1375 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy
->cpu
,
1376 policy
->min
, policy
->max
);
1378 memcpy(&policy
->cpuinfo
, &data
->cpuinfo
, sizeof(struct cpufreq_cpuinfo
));
1380 if (policy
->min
> data
->min
&& policy
->min
> policy
->max
) {
1385 /* verify the cpu speed can be set within this limit */
1386 ret
= cpufreq_driver
->verify(policy
);
1390 /* adjust if necessary - all reasons */
1391 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1392 CPUFREQ_ADJUST
, policy
);
1394 /* adjust if necessary - hardware incompatibility*/
1395 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1396 CPUFREQ_INCOMPATIBLE
, policy
);
1398 /* verify the cpu speed can be set within this limit,
1399 which might be different to the first one */
1400 ret
= cpufreq_driver
->verify(policy
);
1404 /* notification of the new policy */
1405 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1406 CPUFREQ_NOTIFY
, policy
);
1408 data
->min
= policy
->min
;
1409 data
->max
= policy
->max
;
1411 dprintk("new min and max freqs are %u - %u kHz\n", data
->min
, data
->max
);
1413 if (cpufreq_driver
->setpolicy
) {
1414 data
->policy
= policy
->policy
;
1415 dprintk("setting range\n");
1416 ret
= cpufreq_driver
->setpolicy(policy
);
1418 if (policy
->governor
!= data
->governor
) {
1419 /* save old, working values */
1420 struct cpufreq_governor
*old_gov
= data
->governor
;
1422 dprintk("governor switch\n");
1424 /* end old governor */
1426 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
1428 /* start new governor */
1429 data
->governor
= policy
->governor
;
1430 if (__cpufreq_governor(data
, CPUFREQ_GOV_START
)) {
1431 /* new governor failed, so re-start old one */
1432 dprintk("starting governor %s failed\n", data
->governor
->name
);
1434 data
->governor
= old_gov
;
1435 __cpufreq_governor(data
, CPUFREQ_GOV_START
);
1440 /* might be a policy change, too, so fall through */
1442 dprintk("governor: change or update limits\n");
1443 __cpufreq_governor(data
, CPUFREQ_GOV_LIMITS
);
1447 cpufreq_debug_enable_ratelimit();
1452 * cpufreq_set_policy - set a new CPUFreq policy
1453 * @policy: policy to be set.
1455 * Sets a new CPU frequency and voltage scaling policy.
1457 int cpufreq_set_policy(struct cpufreq_policy
*policy
)
1460 struct cpufreq_policy
*data
;
1465 data
= cpufreq_cpu_get(policy
->cpu
);
1472 mutex_lock(&data
->lock
);
1474 ret
= __cpufreq_set_policy(data
, policy
);
1475 data
->user_policy
.min
= data
->min
;
1476 data
->user_policy
.max
= data
->max
;
1477 data
->user_policy
.policy
= data
->policy
;
1478 data
->user_policy
.governor
= data
->governor
;
1480 mutex_unlock(&data
->lock
);
1482 unlock_cpu_hotplug();
1483 cpufreq_cpu_put(data
);
1487 EXPORT_SYMBOL(cpufreq_set_policy
);
1491 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1492 * @cpu: CPU which shall be re-evaluated
1494 * Usefull for policy notifiers which have different necessities
1495 * at different times.
1497 int cpufreq_update_policy(unsigned int cpu
)
1499 struct cpufreq_policy
*data
= cpufreq_cpu_get(cpu
);
1500 struct cpufreq_policy policy
;
1507 mutex_lock(&data
->lock
);
1509 dprintk("updating policy for CPU %u\n", cpu
);
1510 memcpy(&policy
, data
, sizeof(struct cpufreq_policy
));
1511 policy
.min
= data
->user_policy
.min
;
1512 policy
.max
= data
->user_policy
.max
;
1513 policy
.policy
= data
->user_policy
.policy
;
1514 policy
.governor
= data
->user_policy
.governor
;
1516 /* BIOS might change freq behind our back
1517 -> ask driver for current freq and notify governors about a change */
1518 if (cpufreq_driver
->get
) {
1519 policy
.cur
= cpufreq_driver
->get(cpu
);
1521 dprintk("Driver did not initialize current freq");
1522 data
->cur
= policy
.cur
;
1524 if (data
->cur
!= policy
.cur
)
1525 cpufreq_out_of_sync(cpu
, data
->cur
, policy
.cur
);
1529 ret
= __cpufreq_set_policy(data
, &policy
);
1531 mutex_unlock(&data
->lock
);
1532 unlock_cpu_hotplug();
1533 cpufreq_cpu_put(data
);
1536 EXPORT_SYMBOL(cpufreq_update_policy
);
1538 #ifdef CONFIG_HOTPLUG_CPU
1539 static int cpufreq_cpu_callback(struct notifier_block
*nfb
,
1540 unsigned long action
, void *hcpu
)
1542 unsigned int cpu
= (unsigned long)hcpu
;
1543 struct cpufreq_policy
*policy
;
1544 struct sys_device
*sys_dev
;
1546 sys_dev
= get_cpu_sysdev(cpu
);
1551 cpufreq_add_dev(sys_dev
);
1553 case CPU_DOWN_PREPARE
:
1555 * We attempt to put this cpu in lowest frequency
1556 * possible before going down. This will permit
1557 * hardware-managed P-State to switch other related
1558 * threads to min or higher speeds if possible.
1560 policy
= cpufreq_cpu_data
[cpu
];
1562 cpufreq_driver_target(policy
, policy
->min
,
1563 CPUFREQ_RELATION_H
);
1567 cpufreq_remove_dev(sys_dev
);
1574 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier
=
1576 .notifier_call
= cpufreq_cpu_callback
,
1578 #endif /* CONFIG_HOTPLUG_CPU */
1580 /*********************************************************************
1581 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1582 *********************************************************************/
1585 * cpufreq_register_driver - register a CPU Frequency driver
1586 * @driver_data: A struct cpufreq_driver containing the values#
1587 * submitted by the CPU Frequency driver.
1589 * Registers a CPU Frequency driver to this core code. This code
1590 * returns zero on success, -EBUSY when another driver got here first
1591 * (and isn't unregistered in the meantime).
1594 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
1596 unsigned long flags
;
1599 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
1600 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
1603 dprintk("trying to register driver %s\n", driver_data
->name
);
1605 if (driver_data
->setpolicy
)
1606 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
1608 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1609 if (cpufreq_driver
) {
1610 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1613 cpufreq_driver
= driver_data
;
1614 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1616 ret
= sysdev_driver_register(&cpu_sysdev_class
,&cpufreq_sysdev_driver
);
1618 if ((!ret
) && !(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
1622 /* check for at least one working CPU */
1623 for (i
=0; i
<NR_CPUS
; i
++)
1624 if (cpufreq_cpu_data
[i
])
1627 /* if all ->init() calls failed, unregister */
1629 dprintk("no CPU initialized for driver %s\n", driver_data
->name
);
1630 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1632 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1633 cpufreq_driver
= NULL
;
1634 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1639 register_hotcpu_notifier(&cpufreq_cpu_notifier
);
1640 dprintk("driver %s up and running\n", driver_data
->name
);
1641 cpufreq_debug_enable_ratelimit();
1646 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
1650 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1652 * Unregister the current CPUFreq driver. Only call this if you have
1653 * the right to do so, i.e. if you have succeeded in initialising before!
1654 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1655 * currently not initialised.
1657 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
1659 unsigned long flags
;
1661 cpufreq_debug_disable_ratelimit();
1663 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
)) {
1664 cpufreq_debug_enable_ratelimit();
1668 dprintk("unregistering driver %s\n", driver
->name
);
1670 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1671 unregister_hotcpu_notifier(&cpufreq_cpu_notifier
);
1673 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1674 cpufreq_driver
= NULL
;
1675 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1679 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);