2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
16 #include <linux/config.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/notifier.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/interrupt.h>
24 #include <linux/spinlock.h>
25 #include <linux/device.h>
26 #include <linux/slab.h>
27 #include <linux/cpu.h>
28 #include <linux/completion.h>
29 #include <linux/mutex.h>
31 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
34 * The "cpufreq driver" - the arch- or hardware-dependend low
35 * level driver of CPUFreq support, and its spinlock. This lock
36 * also protects the cpufreq_cpu_data array.
38 static struct cpufreq_driver
*cpufreq_driver
;
39 static struct cpufreq_policy
*cpufreq_cpu_data
[NR_CPUS
];
40 static DEFINE_SPINLOCK(cpufreq_driver_lock
);
42 /* internal prototypes */
43 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
);
44 static void handle_update(void *data
);
47 * Two notifier lists: the "policy" list is involved in the
48 * validation process for a new CPU frequency policy; the
49 * "transition" list for kernel code that needs to handle
50 * changes to devices when the CPU clock speed changes.
51 * The mutex locks both lists.
53 static struct notifier_block
*cpufreq_policy_notifier_list
;
54 static struct notifier_block
*cpufreq_transition_notifier_list
;
55 static DECLARE_RWSEM (cpufreq_notifier_rwsem
);
58 static LIST_HEAD(cpufreq_governor_list
);
59 static DEFINE_MUTEX (cpufreq_governor_mutex
);
61 struct cpufreq_policy
* cpufreq_cpu_get(unsigned int cpu
)
63 struct cpufreq_policy
*data
;
69 /* get the cpufreq driver */
70 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
75 if (!try_module_get(cpufreq_driver
->owner
))
80 data
= cpufreq_cpu_data
[cpu
];
83 goto err_out_put_module
;
85 if (!kobject_get(&data
->kobj
))
86 goto err_out_put_module
;
89 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
94 module_put(cpufreq_driver
->owner
);
96 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
100 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
102 void cpufreq_cpu_put(struct cpufreq_policy
*data
)
104 kobject_put(&data
->kobj
);
105 module_put(cpufreq_driver
->owner
);
107 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
110 /*********************************************************************
111 * UNIFIED DEBUG HELPERS *
112 *********************************************************************/
113 #ifdef CONFIG_CPU_FREQ_DEBUG
115 /* what part(s) of the CPUfreq subsystem are debugged? */
116 static unsigned int debug
;
118 /* is the debug output ratelimit'ed using printk_ratelimit? User can
119 * set or modify this value.
121 static unsigned int debug_ratelimit
= 1;
123 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
124 * loading of a cpufreq driver, temporarily disabled when a new policy
125 * is set, and disabled upon cpufreq driver removal
127 static unsigned int disable_ratelimit
= 1;
128 static DEFINE_SPINLOCK(disable_ratelimit_lock
);
130 static void cpufreq_debug_enable_ratelimit(void)
134 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
135 if (disable_ratelimit
)
137 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
140 static void cpufreq_debug_disable_ratelimit(void)
144 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
146 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
149 void cpufreq_debug_printk(unsigned int type
, const char *prefix
, const char *fmt
, ...)
158 spin_lock_irqsave(&disable_ratelimit_lock
, flags
);
159 if (!disable_ratelimit
&& debug_ratelimit
&& !printk_ratelimit()) {
160 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
163 spin_unlock_irqrestore(&disable_ratelimit_lock
, flags
);
165 len
= snprintf(s
, 256, KERN_DEBUG
"%s: ", prefix
);
168 len
+= vsnprintf(&s
[len
], (256 - len
), fmt
, args
);
176 EXPORT_SYMBOL(cpufreq_debug_printk
);
179 module_param(debug
, uint
, 0644);
180 MODULE_PARM_DESC(debug
, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
182 module_param(debug_ratelimit
, uint
, 0644);
183 MODULE_PARM_DESC(debug_ratelimit
, "CPUfreq debugging: set to 0 to disable ratelimiting.");
185 #else /* !CONFIG_CPU_FREQ_DEBUG */
187 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
188 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
190 #endif /* CONFIG_CPU_FREQ_DEBUG */
193 /*********************************************************************
194 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
195 *********************************************************************/
198 * adjust_jiffies - adjust the system "loops_per_jiffy"
200 * This function alters the system "loops_per_jiffy" for the clock
201 * speed change. Note that loops_per_jiffy cannot be updated on SMP
202 * systems as each CPU might be scaled differently. So, use the arch
203 * per-CPU loops_per_jiffy value wherever possible.
206 static unsigned long l_p_j_ref
;
207 static unsigned int l_p_j_ref_freq
;
209 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
211 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
214 if (!l_p_j_ref_freq
) {
215 l_p_j_ref
= loops_per_jiffy
;
216 l_p_j_ref_freq
= ci
->old
;
217 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref
, l_p_j_ref_freq
);
219 if ((val
== CPUFREQ_PRECHANGE
&& ci
->old
< ci
->new) ||
220 (val
== CPUFREQ_POSTCHANGE
&& ci
->old
> ci
->new) ||
221 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
222 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
, ci
->new);
223 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy
, ci
->new);
227 static inline void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
) { return; }
232 * cpufreq_notify_transition - call notifier chain and adjust_jiffies on frequency transition
234 * This function calls the transition notifiers and the "adjust_jiffies" function. It is called
235 * twice on all CPU frequency changes that have external effects.
237 void cpufreq_notify_transition(struct cpufreq_freqs
*freqs
, unsigned int state
)
239 BUG_ON(irqs_disabled());
241 freqs
->flags
= cpufreq_driver
->flags
;
242 dprintk("notification %u of frequency transition to %u kHz\n", state
, freqs
->new);
244 down_read(&cpufreq_notifier_rwsem
);
246 case CPUFREQ_PRECHANGE
:
247 /* detect if the driver reported a value as "old frequency" which
248 * is not equal to what the cpufreq core thinks is "old frequency".
250 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
251 if ((likely(cpufreq_cpu_data
[freqs
->cpu
])) &&
252 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cpu
== freqs
->cpu
)) &&
253 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cur
)) &&
254 (unlikely(freqs
->old
!= cpufreq_cpu_data
[freqs
->cpu
]->cur
)))
256 dprintk(KERN_WARNING
"Warning: CPU frequency is %u, "
257 "cpufreq assumed %u kHz.\n", freqs
->old
, cpufreq_cpu_data
[freqs
->cpu
]->cur
);
258 freqs
->old
= cpufreq_cpu_data
[freqs
->cpu
]->cur
;
261 notifier_call_chain(&cpufreq_transition_notifier_list
, CPUFREQ_PRECHANGE
, freqs
);
262 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
264 case CPUFREQ_POSTCHANGE
:
265 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
266 notifier_call_chain(&cpufreq_transition_notifier_list
, CPUFREQ_POSTCHANGE
, freqs
);
267 if ((likely(cpufreq_cpu_data
[freqs
->cpu
])) &&
268 (likely(cpufreq_cpu_data
[freqs
->cpu
]->cpu
== freqs
->cpu
)))
269 cpufreq_cpu_data
[freqs
->cpu
]->cur
= freqs
->new;
272 up_read(&cpufreq_notifier_rwsem
);
274 EXPORT_SYMBOL_GPL(cpufreq_notify_transition
);
278 /*********************************************************************
280 *********************************************************************/
283 * cpufreq_parse_governor - parse a governor string
285 static int cpufreq_parse_governor (char *str_governor
, unsigned int *policy
,
286 struct cpufreq_governor
**governor
)
290 if (cpufreq_driver
->setpolicy
) {
291 if (!strnicmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
292 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
294 } else if (!strnicmp(str_governor
, "powersave", CPUFREQ_NAME_LEN
)) {
295 *policy
= CPUFREQ_POLICY_POWERSAVE
;
300 struct cpufreq_governor
*t
;
301 mutex_lock(&cpufreq_governor_mutex
);
302 if (!cpufreq_driver
|| !cpufreq_driver
->target
)
304 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
305 if (!strnicmp(str_governor
,t
->name
,CPUFREQ_NAME_LEN
)) {
307 mutex_unlock(&cpufreq_governor_mutex
);
312 mutex_unlock(&cpufreq_governor_mutex
);
316 EXPORT_SYMBOL_GPL(cpufreq_parse_governor
);
319 /* drivers/base/cpu.c */
320 extern struct sysdev_class cpu_sysdev_class
;
324 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
326 * Write out information from cpufreq_driver->policy[cpu]; object must be
330 #define show_one(file_name, object) \
331 static ssize_t show_##file_name \
332 (struct cpufreq_policy * policy, char *buf) \
334 return sprintf (buf, "%u\n", policy->object); \
337 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
338 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
339 show_one(scaling_min_freq
, min
);
340 show_one(scaling_max_freq
, max
);
341 show_one(scaling_cur_freq
, cur
);
344 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
346 #define store_one(file_name, object) \
347 static ssize_t store_##file_name \
348 (struct cpufreq_policy * policy, const char *buf, size_t count) \
350 unsigned int ret = -EINVAL; \
351 struct cpufreq_policy new_policy; \
353 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
357 ret = sscanf (buf, "%u", &new_policy.object); \
361 ret = cpufreq_set_policy(&new_policy); \
363 return ret ? ret : count; \
366 store_one(scaling_min_freq
,min
);
367 store_one(scaling_max_freq
,max
);
370 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
372 static ssize_t
show_cpuinfo_cur_freq (struct cpufreq_policy
* policy
, char *buf
)
374 unsigned int cur_freq
= cpufreq_get(policy
->cpu
);
376 return sprintf(buf
, "<unknown>");
377 return sprintf(buf
, "%u\n", cur_freq
);
382 * show_scaling_governor - show the current policy for the specified CPU
384 static ssize_t
show_scaling_governor (struct cpufreq_policy
* policy
, char *buf
)
386 if(policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
387 return sprintf(buf
, "powersave\n");
388 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
389 return sprintf(buf
, "performance\n");
390 else if (policy
->governor
)
391 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", policy
->governor
->name
);
397 * store_scaling_governor - store policy for the specified CPU
399 static ssize_t
store_scaling_governor (struct cpufreq_policy
* policy
,
400 const char *buf
, size_t count
)
402 unsigned int ret
= -EINVAL
;
403 char str_governor
[16];
404 struct cpufreq_policy new_policy
;
406 ret
= cpufreq_get_policy(&new_policy
, policy
->cpu
);
410 ret
= sscanf (buf
, "%15s", str_governor
);
414 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
, &new_policy
.governor
))
417 ret
= cpufreq_set_policy(&new_policy
);
419 return ret
? ret
: count
;
423 * show_scaling_driver - show the cpufreq driver currently loaded
425 static ssize_t
show_scaling_driver (struct cpufreq_policy
* policy
, char *buf
)
427 return scnprintf(buf
, CPUFREQ_NAME_LEN
, "%s\n", cpufreq_driver
->name
);
431 * show_scaling_available_governors - show the available CPUfreq governors
433 static ssize_t
show_scaling_available_governors (struct cpufreq_policy
* policy
,
437 struct cpufreq_governor
*t
;
439 if (!cpufreq_driver
->target
) {
440 i
+= sprintf(buf
, "performance powersave");
444 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
445 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char)) - (CPUFREQ_NAME_LEN
+ 2)))
447 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_LEN
, "%s ", t
->name
);
450 i
+= sprintf(&buf
[i
], "\n");
454 * show_affected_cpus - show the CPUs affected by each transition
456 static ssize_t
show_affected_cpus (struct cpufreq_policy
* policy
, char *buf
)
461 for_each_cpu_mask(cpu
, policy
->cpus
) {
463 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
464 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
465 if (i
>= (PAGE_SIZE
- 5))
468 i
+= sprintf(&buf
[i
], "\n");
473 #define define_one_ro(_name) \
474 static struct freq_attr _name = \
475 __ATTR(_name, 0444, show_##_name, NULL)
477 #define define_one_ro0400(_name) \
478 static struct freq_attr _name = \
479 __ATTR(_name, 0400, show_##_name, NULL)
481 #define define_one_rw(_name) \
482 static struct freq_attr _name = \
483 __ATTR(_name, 0644, show_##_name, store_##_name)
485 define_one_ro0400(cpuinfo_cur_freq
);
486 define_one_ro(cpuinfo_min_freq
);
487 define_one_ro(cpuinfo_max_freq
);
488 define_one_ro(scaling_available_governors
);
489 define_one_ro(scaling_driver
);
490 define_one_ro(scaling_cur_freq
);
491 define_one_ro(affected_cpus
);
492 define_one_rw(scaling_min_freq
);
493 define_one_rw(scaling_max_freq
);
494 define_one_rw(scaling_governor
);
496 static struct attribute
* default_attrs
[] = {
497 &cpuinfo_min_freq
.attr
,
498 &cpuinfo_max_freq
.attr
,
499 &scaling_min_freq
.attr
,
500 &scaling_max_freq
.attr
,
502 &scaling_governor
.attr
,
503 &scaling_driver
.attr
,
504 &scaling_available_governors
.attr
,
508 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
509 #define to_attr(a) container_of(a,struct freq_attr,attr)
511 static ssize_t
show(struct kobject
* kobj
, struct attribute
* attr
,char * buf
)
513 struct cpufreq_policy
* policy
= to_policy(kobj
);
514 struct freq_attr
* fattr
= to_attr(attr
);
516 policy
= cpufreq_cpu_get(policy
->cpu
);
519 ret
= fattr
->show
? fattr
->show(policy
,buf
) : -EIO
;
520 cpufreq_cpu_put(policy
);
524 static ssize_t
store(struct kobject
* kobj
, struct attribute
* attr
,
525 const char * buf
, size_t count
)
527 struct cpufreq_policy
* policy
= to_policy(kobj
);
528 struct freq_attr
* fattr
= to_attr(attr
);
530 policy
= cpufreq_cpu_get(policy
->cpu
);
533 ret
= fattr
->store
? fattr
->store(policy
,buf
,count
) : -EIO
;
534 cpufreq_cpu_put(policy
);
538 static void cpufreq_sysfs_release(struct kobject
* kobj
)
540 struct cpufreq_policy
* policy
= to_policy(kobj
);
541 dprintk("last reference is dropped\n");
542 complete(&policy
->kobj_unregister
);
545 static struct sysfs_ops sysfs_ops
= {
550 static struct kobj_type ktype_cpufreq
= {
551 .sysfs_ops
= &sysfs_ops
,
552 .default_attrs
= default_attrs
,
553 .release
= cpufreq_sysfs_release
,
558 * cpufreq_add_dev - add a CPU device
560 * Adds the cpufreq interface for a CPU device.
562 static int cpufreq_add_dev (struct sys_device
* sys_dev
)
564 unsigned int cpu
= sys_dev
->id
;
566 struct cpufreq_policy new_policy
;
567 struct cpufreq_policy
*policy
;
568 struct freq_attr
**drv_attr
;
572 if (cpu_is_offline(cpu
))
575 cpufreq_debug_disable_ratelimit();
576 dprintk("adding CPU %u\n", cpu
);
579 /* check whether a different CPU already registered this
580 * CPU because it is in the same boat. */
581 policy
= cpufreq_cpu_get(cpu
);
582 if (unlikely(policy
)) {
583 dprintk("CPU already managed, adding link\n");
584 sysfs_create_link(&sys_dev
->kobj
, &policy
->kobj
, "cpufreq");
585 cpufreq_debug_enable_ratelimit();
590 if (!try_module_get(cpufreq_driver
->owner
)) {
595 policy
= kzalloc(sizeof(struct cpufreq_policy
), GFP_KERNEL
);
602 policy
->cpus
= cpumask_of_cpu(cpu
);
604 mutex_init(&policy
->lock
);
605 mutex_lock(&policy
->lock
);
606 init_completion(&policy
->kobj_unregister
);
607 INIT_WORK(&policy
->update
, handle_update
, (void *)(long)cpu
);
609 /* call driver. From then on the cpufreq must be able
610 * to accept all calls to ->verify and ->setpolicy for this CPU
612 ret
= cpufreq_driver
->init(policy
);
614 dprintk("initialization failed\n");
615 mutex_unlock(&policy
->lock
);
619 memcpy(&new_policy
, policy
, sizeof(struct cpufreq_policy
));
621 /* prepare interface data */
622 policy
->kobj
.parent
= &sys_dev
->kobj
;
623 policy
->kobj
.ktype
= &ktype_cpufreq
;
624 strlcpy(policy
->kobj
.name
, "cpufreq", KOBJ_NAME_LEN
);
626 ret
= kobject_register(&policy
->kobj
);
628 mutex_unlock(&policy
->lock
);
629 goto err_out_driver_exit
;
631 /* set up files for this cpu device */
632 drv_attr
= cpufreq_driver
->attr
;
633 while ((drv_attr
) && (*drv_attr
)) {
634 sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
637 if (cpufreq_driver
->get
)
638 sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
639 if (cpufreq_driver
->target
)
640 sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
642 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
643 for_each_cpu_mask(j
, policy
->cpus
)
644 cpufreq_cpu_data
[j
] = policy
;
645 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
646 policy
->governor
= NULL
; /* to assure that the starting sequence is
647 * run in cpufreq_set_policy */
648 mutex_unlock(&policy
->lock
);
650 /* set default policy */
652 ret
= cpufreq_set_policy(&new_policy
);
654 dprintk("setting policy failed\n");
655 goto err_out_unregister
;
658 module_put(cpufreq_driver
->owner
);
659 dprintk("initialization complete\n");
660 cpufreq_debug_enable_ratelimit();
666 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
667 for_each_cpu_mask(j
, policy
->cpus
)
668 cpufreq_cpu_data
[j
] = NULL
;
669 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
671 kobject_unregister(&policy
->kobj
);
672 wait_for_completion(&policy
->kobj_unregister
);
675 if (cpufreq_driver
->exit
)
676 cpufreq_driver
->exit(policy
);
682 module_put(cpufreq_driver
->owner
);
684 cpufreq_debug_enable_ratelimit();
690 * cpufreq_remove_dev - remove a CPU device
692 * Removes the cpufreq interface for a CPU device.
694 static int cpufreq_remove_dev (struct sys_device
* sys_dev
)
696 unsigned int cpu
= sys_dev
->id
;
698 struct cpufreq_policy
*data
;
700 struct sys_device
*cpu_sys_dev
;
704 cpufreq_debug_disable_ratelimit();
705 dprintk("unregistering CPU %u\n", cpu
);
707 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
708 data
= cpufreq_cpu_data
[cpu
];
711 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
712 cpufreq_debug_enable_ratelimit();
715 cpufreq_cpu_data
[cpu
] = NULL
;
719 /* if this isn't the CPU which is the parent of the kobj, we
720 * only need to unlink, put and exit
722 if (unlikely(cpu
!= data
->cpu
)) {
723 dprintk("removing link\n");
724 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
725 sysfs_remove_link(&sys_dev
->kobj
, "cpufreq");
726 cpufreq_cpu_put(data
);
727 cpufreq_debug_enable_ratelimit();
733 if (!kobject_get(&data
->kobj
)) {
734 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
735 cpufreq_debug_enable_ratelimit();
740 /* if we have other CPUs still registered, we need to unlink them,
741 * or else wait_for_completion below will lock up. Clean the
742 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
745 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
746 for_each_cpu_mask(j
, data
->cpus
) {
749 cpufreq_cpu_data
[j
] = NULL
;
753 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
755 if (unlikely(cpus_weight(data
->cpus
) > 1)) {
756 for_each_cpu_mask(j
, data
->cpus
) {
759 dprintk("removing link for cpu %u\n", j
);
760 cpu_sys_dev
= get_cpu_sysdev(j
);
761 sysfs_remove_link(&cpu_sys_dev
->kobj
, "cpufreq");
762 cpufreq_cpu_put(data
);
766 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
769 mutex_lock(&data
->lock
);
770 if (cpufreq_driver
->target
)
771 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
772 mutex_unlock(&data
->lock
);
774 kobject_unregister(&data
->kobj
);
776 kobject_put(&data
->kobj
);
778 /* we need to make sure that the underlying kobj is actually
779 * not referenced anymore by anybody before we proceed with
782 dprintk("waiting for dropping of refcount\n");
783 wait_for_completion(&data
->kobj_unregister
);
784 dprintk("wait complete\n");
786 if (cpufreq_driver
->exit
)
787 cpufreq_driver
->exit(data
);
791 cpufreq_debug_enable_ratelimit();
797 static void handle_update(void *data
)
799 unsigned int cpu
= (unsigned int)(long)data
;
800 dprintk("handle_update for cpu %u called\n", cpu
);
801 cpufreq_update_policy(cpu
);
805 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
807 * @old_freq: CPU frequency the kernel thinks the CPU runs at
808 * @new_freq: CPU frequency the CPU actually runs at
810 * We adjust to current frequency first, and need to clean up later. So either call
811 * to cpufreq_update_policy() or schedule handle_update()).
813 static void cpufreq_out_of_sync(unsigned int cpu
, unsigned int old_freq
, unsigned int new_freq
)
815 struct cpufreq_freqs freqs
;
817 dprintk(KERN_WARNING
"Warning: CPU frequency out of sync: cpufreq and timing "
818 "core thinks of %u, is %u kHz.\n", old_freq
, new_freq
);
821 freqs
.old
= old_freq
;
822 freqs
.new = new_freq
;
823 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
824 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
829 * cpufreq_quick_get - get the CPU frequency (in kHz) frpm policy->cur
832 * This is the last known freq, without actually getting it from the driver.
833 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
835 unsigned int cpufreq_quick_get(unsigned int cpu
)
837 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
838 unsigned int ret
= 0;
841 mutex_lock(&policy
->lock
);
843 mutex_unlock(&policy
->lock
);
844 cpufreq_cpu_put(policy
);
849 EXPORT_SYMBOL(cpufreq_quick_get
);
853 * cpufreq_get - get the current CPU frequency (in kHz)
856 * Get the CPU current (static) CPU frequency
858 unsigned int cpufreq_get(unsigned int cpu
)
860 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
861 unsigned int ret
= 0;
866 if (!cpufreq_driver
->get
)
869 mutex_lock(&policy
->lock
);
871 ret
= cpufreq_driver
->get(cpu
);
873 if (ret
&& policy
->cur
&& !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
))
875 /* verify no discrepancy between actual and saved value exists */
876 if (unlikely(ret
!= policy
->cur
)) {
877 cpufreq_out_of_sync(cpu
, policy
->cur
, ret
);
878 schedule_work(&policy
->update
);
882 mutex_unlock(&policy
->lock
);
885 cpufreq_cpu_put(policy
);
889 EXPORT_SYMBOL(cpufreq_get
);
893 * cpufreq_suspend - let the low level driver prepare for suspend
896 static int cpufreq_suspend(struct sys_device
* sysdev
, pm_message_t pmsg
)
898 int cpu
= sysdev
->id
;
899 unsigned int ret
= 0;
900 unsigned int cur_freq
= 0;
901 struct cpufreq_policy
*cpu_policy
;
903 dprintk("resuming cpu %u\n", cpu
);
905 if (!cpu_online(cpu
))
908 /* we may be lax here as interrupts are off. Nonetheless
909 * we need to grab the correct cpu policy, as to check
910 * whether we really run on this CPU.
913 cpu_policy
= cpufreq_cpu_get(cpu
);
917 /* only handle each CPU group once */
918 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
919 cpufreq_cpu_put(cpu_policy
);
923 if (cpufreq_driver
->suspend
) {
924 ret
= cpufreq_driver
->suspend(cpu_policy
, pmsg
);
926 printk(KERN_ERR
"cpufreq: suspend failed in ->suspend "
927 "step on CPU %u\n", cpu_policy
->cpu
);
928 cpufreq_cpu_put(cpu_policy
);
934 if (cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)
937 if (cpufreq_driver
->get
)
938 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
940 if (!cur_freq
|| !cpu_policy
->cur
) {
941 printk(KERN_ERR
"cpufreq: suspend failed to assert current "
942 "frequency is what timing core thinks it is.\n");
946 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
947 struct cpufreq_freqs freqs
;
949 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
950 dprintk(KERN_DEBUG
"Warning: CPU frequency is %u, "
951 "cpufreq assumed %u kHz.\n",
952 cur_freq
, cpu_policy
->cur
);
955 freqs
.old
= cpu_policy
->cur
;
956 freqs
.new = cur_freq
;
958 notifier_call_chain(&cpufreq_transition_notifier_list
,
959 CPUFREQ_SUSPENDCHANGE
, &freqs
);
960 adjust_jiffies(CPUFREQ_SUSPENDCHANGE
, &freqs
);
962 cpu_policy
->cur
= cur_freq
;
966 cpufreq_cpu_put(cpu_policy
);
971 * cpufreq_resume - restore proper CPU frequency handling after resume
973 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
974 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
975 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
978 static int cpufreq_resume(struct sys_device
* sysdev
)
980 int cpu
= sysdev
->id
;
981 unsigned int ret
= 0;
982 struct cpufreq_policy
*cpu_policy
;
984 dprintk("resuming cpu %u\n", cpu
);
986 if (!cpu_online(cpu
))
989 /* we may be lax here as interrupts are off. Nonetheless
990 * we need to grab the correct cpu policy, as to check
991 * whether we really run on this CPU.
994 cpu_policy
= cpufreq_cpu_get(cpu
);
998 /* only handle each CPU group once */
999 if (unlikely(cpu_policy
->cpu
!= cpu
)) {
1000 cpufreq_cpu_put(cpu_policy
);
1004 if (cpufreq_driver
->resume
) {
1005 ret
= cpufreq_driver
->resume(cpu_policy
);
1007 printk(KERN_ERR
"cpufreq: resume failed in ->resume "
1008 "step on CPU %u\n", cpu_policy
->cpu
);
1009 cpufreq_cpu_put(cpu_policy
);
1014 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1015 unsigned int cur_freq
= 0;
1017 if (cpufreq_driver
->get
)
1018 cur_freq
= cpufreq_driver
->get(cpu_policy
->cpu
);
1020 if (!cur_freq
|| !cpu_policy
->cur
) {
1021 printk(KERN_ERR
"cpufreq: resume failed to assert "
1022 "current frequency is what timing core "
1027 if (unlikely(cur_freq
!= cpu_policy
->cur
)) {
1028 struct cpufreq_freqs freqs
;
1030 if (!(cpufreq_driver
->flags
& CPUFREQ_PM_NO_WARN
))
1031 dprintk(KERN_WARNING
"Warning: CPU frequency"
1032 "is %u, cpufreq assumed %u kHz.\n",
1033 cur_freq
, cpu_policy
->cur
);
1036 freqs
.old
= cpu_policy
->cur
;
1037 freqs
.new = cur_freq
;
1039 notifier_call_chain(&cpufreq_transition_notifier_list
,
1040 CPUFREQ_RESUMECHANGE
, &freqs
);
1041 adjust_jiffies(CPUFREQ_RESUMECHANGE
, &freqs
);
1043 cpu_policy
->cur
= cur_freq
;
1048 schedule_work(&cpu_policy
->update
);
1049 cpufreq_cpu_put(cpu_policy
);
1053 static struct sysdev_driver cpufreq_sysdev_driver
= {
1054 .add
= cpufreq_add_dev
,
1055 .remove
= cpufreq_remove_dev
,
1056 .suspend
= cpufreq_suspend
,
1057 .resume
= cpufreq_resume
,
1061 /*********************************************************************
1062 * NOTIFIER LISTS INTERFACE *
1063 *********************************************************************/
1066 * cpufreq_register_notifier - register a driver with cpufreq
1067 * @nb: notifier function to register
1068 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1070 * Add a driver to one of two lists: either a list of drivers that
1071 * are notified about clock rate changes (once before and once after
1072 * the transition), or a list of drivers that are notified about
1073 * changes in cpufreq policy.
1075 * This function may sleep, and has the same return conditions as
1076 * notifier_chain_register.
1078 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1082 down_write(&cpufreq_notifier_rwsem
);
1084 case CPUFREQ_TRANSITION_NOTIFIER
:
1085 ret
= notifier_chain_register(&cpufreq_transition_notifier_list
, nb
);
1087 case CPUFREQ_POLICY_NOTIFIER
:
1088 ret
= notifier_chain_register(&cpufreq_policy_notifier_list
, nb
);
1093 up_write(&cpufreq_notifier_rwsem
);
1097 EXPORT_SYMBOL(cpufreq_register_notifier
);
1101 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1102 * @nb: notifier block to be unregistered
1103 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1105 * Remove a driver from the CPU frequency notifier list.
1107 * This function may sleep, and has the same return conditions as
1108 * notifier_chain_unregister.
1110 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1114 down_write(&cpufreq_notifier_rwsem
);
1116 case CPUFREQ_TRANSITION_NOTIFIER
:
1117 ret
= notifier_chain_unregister(&cpufreq_transition_notifier_list
, nb
);
1119 case CPUFREQ_POLICY_NOTIFIER
:
1120 ret
= notifier_chain_unregister(&cpufreq_policy_notifier_list
, nb
);
1125 up_write(&cpufreq_notifier_rwsem
);
1129 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1132 /*********************************************************************
1134 *********************************************************************/
1137 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1138 unsigned int target_freq
,
1139 unsigned int relation
)
1141 int retval
= -EINVAL
;
1144 dprintk("target for CPU %u: %u kHz, relation %u\n", policy
->cpu
,
1145 target_freq
, relation
);
1146 if (cpu_online(policy
->cpu
) && cpufreq_driver
->target
)
1147 retval
= cpufreq_driver
->target(policy
, target_freq
, relation
);
1149 unlock_cpu_hotplug();
1153 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1155 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1156 unsigned int target_freq
,
1157 unsigned int relation
)
1161 policy
= cpufreq_cpu_get(policy
->cpu
);
1165 mutex_lock(&policy
->lock
);
1167 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1169 mutex_unlock(&policy
->lock
);
1171 cpufreq_cpu_put(policy
);
1175 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1178 static int __cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
)
1182 if (!try_module_get(policy
->governor
->owner
))
1185 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy
->cpu
, event
);
1186 ret
= policy
->governor
->governor(policy
, event
);
1188 /* we keep one module reference alive for each CPU governed by this CPU */
1189 if ((event
!= CPUFREQ_GOV_START
) || ret
)
1190 module_put(policy
->governor
->owner
);
1191 if ((event
== CPUFREQ_GOV_STOP
) && !ret
)
1192 module_put(policy
->governor
->owner
);
1198 int cpufreq_governor(unsigned int cpu
, unsigned int event
)
1201 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1206 mutex_lock(&policy
->lock
);
1207 ret
= __cpufreq_governor(policy
, event
);
1208 mutex_unlock(&policy
->lock
);
1210 cpufreq_cpu_put(policy
);
1214 EXPORT_SYMBOL_GPL(cpufreq_governor
);
1217 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1219 struct cpufreq_governor
*t
;
1224 mutex_lock(&cpufreq_governor_mutex
);
1226 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
1227 if (!strnicmp(governor
->name
,t
->name
,CPUFREQ_NAME_LEN
)) {
1228 mutex_unlock(&cpufreq_governor_mutex
);
1232 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1234 mutex_unlock(&cpufreq_governor_mutex
);
1238 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1241 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1246 mutex_lock(&cpufreq_governor_mutex
);
1247 list_del(&governor
->governor_list
);
1248 mutex_unlock(&cpufreq_governor_mutex
);
1251 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1255 /*********************************************************************
1256 * POLICY INTERFACE *
1257 *********************************************************************/
1260 * cpufreq_get_policy - get the current cpufreq_policy
1261 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1263 * Reads the current cpufreq policy.
1265 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
1267 struct cpufreq_policy
*cpu_policy
;
1271 cpu_policy
= cpufreq_cpu_get(cpu
);
1275 mutex_lock(&cpu_policy
->lock
);
1276 memcpy(policy
, cpu_policy
, sizeof(struct cpufreq_policy
));
1277 mutex_unlock(&cpu_policy
->lock
);
1279 cpufreq_cpu_put(cpu_policy
);
1283 EXPORT_SYMBOL(cpufreq_get_policy
);
1286 static int __cpufreq_set_policy(struct cpufreq_policy
*data
, struct cpufreq_policy
*policy
)
1290 cpufreq_debug_disable_ratelimit();
1291 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy
->cpu
,
1292 policy
->min
, policy
->max
);
1294 memcpy(&policy
->cpuinfo
,
1296 sizeof(struct cpufreq_cpuinfo
));
1298 /* verify the cpu speed can be set within this limit */
1299 ret
= cpufreq_driver
->verify(policy
);
1303 down_read(&cpufreq_notifier_rwsem
);
1305 /* adjust if necessary - all reasons */
1306 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_ADJUST
,
1309 /* adjust if necessary - hardware incompatibility*/
1310 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_INCOMPATIBLE
,
1313 /* verify the cpu speed can be set within this limit,
1314 which might be different to the first one */
1315 ret
= cpufreq_driver
->verify(policy
);
1317 up_read(&cpufreq_notifier_rwsem
);
1321 /* notification of the new policy */
1322 notifier_call_chain(&cpufreq_policy_notifier_list
, CPUFREQ_NOTIFY
,
1325 up_read(&cpufreq_notifier_rwsem
);
1327 data
->min
= policy
->min
;
1328 data
->max
= policy
->max
;
1330 dprintk("new min and max freqs are %u - %u kHz\n", data
->min
, data
->max
);
1332 if (cpufreq_driver
->setpolicy
) {
1333 data
->policy
= policy
->policy
;
1334 dprintk("setting range\n");
1335 ret
= cpufreq_driver
->setpolicy(policy
);
1337 if (policy
->governor
!= data
->governor
) {
1338 /* save old, working values */
1339 struct cpufreq_governor
*old_gov
= data
->governor
;
1341 dprintk("governor switch\n");
1343 /* end old governor */
1345 __cpufreq_governor(data
, CPUFREQ_GOV_STOP
);
1347 /* start new governor */
1348 data
->governor
= policy
->governor
;
1349 if (__cpufreq_governor(data
, CPUFREQ_GOV_START
)) {
1350 /* new governor failed, so re-start old one */
1351 dprintk("starting governor %s failed\n", data
->governor
->name
);
1353 data
->governor
= old_gov
;
1354 __cpufreq_governor(data
, CPUFREQ_GOV_START
);
1359 /* might be a policy change, too, so fall through */
1361 dprintk("governor: change or update limits\n");
1362 __cpufreq_governor(data
, CPUFREQ_GOV_LIMITS
);
1366 cpufreq_debug_enable_ratelimit();
1371 * cpufreq_set_policy - set a new CPUFreq policy
1372 * @policy: policy to be set.
1374 * Sets a new CPU frequency and voltage scaling policy.
1376 int cpufreq_set_policy(struct cpufreq_policy
*policy
)
1379 struct cpufreq_policy
*data
;
1384 data
= cpufreq_cpu_get(policy
->cpu
);
1389 mutex_lock(&data
->lock
);
1391 ret
= __cpufreq_set_policy(data
, policy
);
1392 data
->user_policy
.min
= data
->min
;
1393 data
->user_policy
.max
= data
->max
;
1394 data
->user_policy
.policy
= data
->policy
;
1395 data
->user_policy
.governor
= data
->governor
;
1397 mutex_unlock(&data
->lock
);
1398 cpufreq_cpu_put(data
);
1402 EXPORT_SYMBOL(cpufreq_set_policy
);
1406 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1407 * @cpu: CPU which shall be re-evaluated
1409 * Usefull for policy notifiers which have different necessities
1410 * at different times.
1412 int cpufreq_update_policy(unsigned int cpu
)
1414 struct cpufreq_policy
*data
= cpufreq_cpu_get(cpu
);
1415 struct cpufreq_policy policy
;
1421 mutex_lock(&data
->lock
);
1423 dprintk("updating policy for CPU %u\n", cpu
);
1426 sizeof(struct cpufreq_policy
));
1427 policy
.min
= data
->user_policy
.min
;
1428 policy
.max
= data
->user_policy
.max
;
1429 policy
.policy
= data
->user_policy
.policy
;
1430 policy
.governor
= data
->user_policy
.governor
;
1432 /* BIOS might change freq behind our back
1433 -> ask driver for current freq and notify governors about a change */
1434 if (cpufreq_driver
->get
) {
1435 policy
.cur
= cpufreq_driver
->get(cpu
);
1436 if (data
->cur
!= policy
.cur
)
1437 cpufreq_out_of_sync(cpu
, data
->cur
, policy
.cur
);
1440 ret
= __cpufreq_set_policy(data
, &policy
);
1442 mutex_unlock(&data
->lock
);
1444 cpufreq_cpu_put(data
);
1447 EXPORT_SYMBOL(cpufreq_update_policy
);
1449 static int __cpuinit
cpufreq_cpu_callback(struct notifier_block
*nfb
,
1450 unsigned long action
, void *hcpu
)
1452 unsigned int cpu
= (unsigned long)hcpu
;
1453 struct cpufreq_policy
*policy
;
1454 struct sys_device
*sys_dev
;
1456 sys_dev
= get_cpu_sysdev(cpu
);
1461 cpufreq_add_dev(sys_dev
);
1463 case CPU_DOWN_PREPARE
:
1465 * We attempt to put this cpu in lowest frequency
1466 * possible before going down. This will permit
1467 * hardware-managed P-State to switch other related
1468 * threads to min or higher speeds if possible.
1470 policy
= cpufreq_cpu_data
[cpu
];
1472 cpufreq_driver_target(policy
, policy
->min
,
1473 CPUFREQ_RELATION_H
);
1477 cpufreq_remove_dev(sys_dev
);
1484 static struct notifier_block cpufreq_cpu_notifier
=
1486 .notifier_call
= cpufreq_cpu_callback
,
1489 /*********************************************************************
1490 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1491 *********************************************************************/
1494 * cpufreq_register_driver - register a CPU Frequency driver
1495 * @driver_data: A struct cpufreq_driver containing the values#
1496 * submitted by the CPU Frequency driver.
1498 * Registers a CPU Frequency driver to this core code. This code
1499 * returns zero on success, -EBUSY when another driver got here first
1500 * (and isn't unregistered in the meantime).
1503 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
1505 unsigned long flags
;
1508 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
1509 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
1512 dprintk("trying to register driver %s\n", driver_data
->name
);
1514 if (driver_data
->setpolicy
)
1515 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
1517 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1518 if (cpufreq_driver
) {
1519 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1522 cpufreq_driver
= driver_data
;
1523 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1525 ret
= sysdev_driver_register(&cpu_sysdev_class
,&cpufreq_sysdev_driver
);
1527 if ((!ret
) && !(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
1531 /* check for at least one working CPU */
1532 for (i
=0; i
<NR_CPUS
; i
++)
1533 if (cpufreq_cpu_data
[i
])
1536 /* if all ->init() calls failed, unregister */
1538 dprintk("no CPU initialized for driver %s\n", driver_data
->name
);
1539 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1541 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1542 cpufreq_driver
= NULL
;
1543 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1548 register_cpu_notifier(&cpufreq_cpu_notifier
);
1549 dprintk("driver %s up and running\n", driver_data
->name
);
1550 cpufreq_debug_enable_ratelimit();
1555 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
1559 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1561 * Unregister the current CPUFreq driver. Only call this if you have
1562 * the right to do so, i.e. if you have succeeded in initialising before!
1563 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1564 * currently not initialised.
1566 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
1568 unsigned long flags
;
1570 cpufreq_debug_disable_ratelimit();
1572 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
)) {
1573 cpufreq_debug_enable_ratelimit();
1577 dprintk("unregistering driver %s\n", driver
->name
);
1579 sysdev_driver_unregister(&cpu_sysdev_class
, &cpufreq_sysdev_driver
);
1580 unregister_cpu_notifier(&cpufreq_cpu_notifier
);
1582 spin_lock_irqsave(&cpufreq_driver_lock
, flags
);
1583 cpufreq_driver
= NULL
;
1584 spin_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1588 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);