2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/syscore_ops.h>
30 #include <linux/tick.h>
31 #include <trace/events/power.h>
34 * The "cpufreq driver" - the arch- or hardware-dependent 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 DEFINE_PER_CPU(struct cpufreq_policy
*, cpufreq_cpu_data
);
40 static DEFINE_PER_CPU(struct cpufreq_policy
*, cpufreq_cpu_data_fallback
);
41 static DEFINE_RWLOCK(cpufreq_driver_lock
);
42 static DEFINE_MUTEX(cpufreq_governor_lock
);
43 static LIST_HEAD(cpufreq_policy_list
);
45 #ifdef CONFIG_HOTPLUG_CPU
46 /* This one keeps track of the previously set governor of a removed CPU */
47 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN
], cpufreq_cpu_governor
);
51 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
52 * all cpufreq/hotplug/workqueue/etc related lock issues.
54 * The rules for this semaphore:
55 * - Any routine that wants to read from the policy structure will
56 * do a down_read on this semaphore.
57 * - Any routine that will write to the policy structure and/or may take away
58 * the policy altogether (eg. CPU hotplug), will hold this lock in write
59 * mode before doing so.
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.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
67 static DEFINE_PER_CPU(struct rw_semaphore
, cpu_policy_rwsem
);
69 #define lock_policy_rwsem(mode, cpu) \
70 static int lock_policy_rwsem_##mode(int cpu) \
72 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \
74 down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \
79 lock_policy_rwsem(read
, cpu
);
80 lock_policy_rwsem(write
, cpu
);
82 #define unlock_policy_rwsem(mode, cpu) \
83 static void unlock_policy_rwsem_##mode(int cpu) \
85 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \
87 up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \
90 unlock_policy_rwsem(read
, cpu
);
91 unlock_policy_rwsem(write
, cpu
);
94 * rwsem to guarantee that cpufreq driver module doesn't unload during critical
97 static DECLARE_RWSEM(cpufreq_rwsem
);
99 /* internal prototypes */
100 static int __cpufreq_governor(struct cpufreq_policy
*policy
,
102 static unsigned int __cpufreq_get(unsigned int cpu
);
103 static void handle_update(struct work_struct
*work
);
106 * Two notifier lists: the "policy" list is involved in the
107 * validation process for a new CPU frequency policy; the
108 * "transition" list for kernel code that needs to handle
109 * changes to devices when the CPU clock speed changes.
110 * The mutex locks both lists.
112 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list
);
113 static struct srcu_notifier_head cpufreq_transition_notifier_list
;
115 static bool init_cpufreq_transition_notifier_list_called
;
116 static int __init
init_cpufreq_transition_notifier_list(void)
118 srcu_init_notifier_head(&cpufreq_transition_notifier_list
);
119 init_cpufreq_transition_notifier_list_called
= true;
122 pure_initcall(init_cpufreq_transition_notifier_list
);
124 static int off __read_mostly
;
125 static int cpufreq_disabled(void)
129 void disable_cpufreq(void)
133 static LIST_HEAD(cpufreq_governor_list
);
134 static DEFINE_MUTEX(cpufreq_governor_mutex
);
136 bool have_governor_per_policy(void)
138 return cpufreq_driver
->have_governor_per_policy
;
140 EXPORT_SYMBOL_GPL(have_governor_per_policy
);
142 struct kobject
*get_governor_parent_kobj(struct cpufreq_policy
*policy
)
144 if (have_governor_per_policy())
145 return &policy
->kobj
;
147 return cpufreq_global_kobject
;
149 EXPORT_SYMBOL_GPL(get_governor_parent_kobj
);
151 static inline u64
get_cpu_idle_time_jiffy(unsigned int cpu
, u64
*wall
)
157 cur_wall_time
= jiffies64_to_cputime64(get_jiffies_64());
159 busy_time
= kcpustat_cpu(cpu
).cpustat
[CPUTIME_USER
];
160 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_SYSTEM
];
161 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_IRQ
];
162 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_SOFTIRQ
];
163 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_STEAL
];
164 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_NICE
];
166 idle_time
= cur_wall_time
- busy_time
;
168 *wall
= cputime_to_usecs(cur_wall_time
);
170 return cputime_to_usecs(idle_time
);
173 u64
get_cpu_idle_time(unsigned int cpu
, u64
*wall
, int io_busy
)
175 u64 idle_time
= get_cpu_idle_time_us(cpu
, io_busy
? wall
: NULL
);
177 if (idle_time
== -1ULL)
178 return get_cpu_idle_time_jiffy(cpu
, wall
);
180 idle_time
+= get_cpu_iowait_time_us(cpu
, wall
);
184 EXPORT_SYMBOL_GPL(get_cpu_idle_time
);
186 struct cpufreq_policy
*cpufreq_cpu_get(unsigned int cpu
)
188 struct cpufreq_policy
*policy
= NULL
;
191 if (cpufreq_disabled() || (cpu
>= nr_cpu_ids
))
194 if (!down_read_trylock(&cpufreq_rwsem
))
197 /* get the cpufreq driver */
198 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
200 if (cpufreq_driver
) {
202 policy
= per_cpu(cpufreq_cpu_data
, cpu
);
204 kobject_get(&policy
->kobj
);
207 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
210 up_read(&cpufreq_rwsem
);
214 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
216 void cpufreq_cpu_put(struct cpufreq_policy
*policy
)
218 if (cpufreq_disabled())
221 kobject_put(&policy
->kobj
);
222 up_read(&cpufreq_rwsem
);
224 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
226 /*********************************************************************
227 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
228 *********************************************************************/
231 * adjust_jiffies - adjust the system "loops_per_jiffy"
233 * This function alters the system "loops_per_jiffy" for the clock
234 * speed change. Note that loops_per_jiffy cannot be updated on SMP
235 * systems as each CPU might be scaled differently. So, use the arch
236 * per-CPU loops_per_jiffy value wherever possible.
239 static unsigned long l_p_j_ref
;
240 static unsigned int l_p_j_ref_freq
;
242 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
244 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
247 if (!l_p_j_ref_freq
) {
248 l_p_j_ref
= loops_per_jiffy
;
249 l_p_j_ref_freq
= ci
->old
;
250 pr_debug("saving %lu as reference value for loops_per_jiffy; "
251 "freq is %u kHz\n", l_p_j_ref
, l_p_j_ref_freq
);
253 if ((val
== CPUFREQ_POSTCHANGE
&& ci
->old
!= ci
->new) ||
254 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
255 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
,
257 pr_debug("scaling loops_per_jiffy to %lu "
258 "for frequency %u kHz\n", loops_per_jiffy
, ci
->new);
262 static inline void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
268 static void __cpufreq_notify_transition(struct cpufreq_policy
*policy
,
269 struct cpufreq_freqs
*freqs
, unsigned int state
)
271 BUG_ON(irqs_disabled());
273 if (cpufreq_disabled())
276 freqs
->flags
= cpufreq_driver
->flags
;
277 pr_debug("notification %u of frequency transition to %u kHz\n",
282 case CPUFREQ_PRECHANGE
:
283 /* detect if the driver reported a value as "old frequency"
284 * which is not equal to what the cpufreq core thinks is
287 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
288 if ((policy
) && (policy
->cpu
== freqs
->cpu
) &&
289 (policy
->cur
) && (policy
->cur
!= freqs
->old
)) {
290 pr_debug("Warning: CPU frequency is"
291 " %u, cpufreq assumed %u kHz.\n",
292 freqs
->old
, policy
->cur
);
293 freqs
->old
= policy
->cur
;
296 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
297 CPUFREQ_PRECHANGE
, freqs
);
298 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
301 case CPUFREQ_POSTCHANGE
:
302 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
303 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs
->new,
304 (unsigned long)freqs
->cpu
);
305 trace_cpu_frequency(freqs
->new, freqs
->cpu
);
306 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
307 CPUFREQ_POSTCHANGE
, freqs
);
308 if (likely(policy
) && likely(policy
->cpu
== freqs
->cpu
))
309 policy
->cur
= freqs
->new;
315 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
316 * on frequency transition.
318 * This function calls the transition notifiers and the "adjust_jiffies"
319 * function. It is called twice on all CPU frequency changes that have
322 void cpufreq_notify_transition(struct cpufreq_policy
*policy
,
323 struct cpufreq_freqs
*freqs
, unsigned int state
)
325 for_each_cpu(freqs
->cpu
, policy
->cpus
)
326 __cpufreq_notify_transition(policy
, freqs
, state
);
328 EXPORT_SYMBOL_GPL(cpufreq_notify_transition
);
331 /*********************************************************************
333 *********************************************************************/
335 static struct cpufreq_governor
*__find_governor(const char *str_governor
)
337 struct cpufreq_governor
*t
;
339 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
)
340 if (!strnicmp(str_governor
, t
->name
, CPUFREQ_NAME_LEN
))
347 * cpufreq_parse_governor - parse a governor string
349 static int cpufreq_parse_governor(char *str_governor
, unsigned int *policy
,
350 struct cpufreq_governor
**governor
)
357 if (cpufreq_driver
->setpolicy
) {
358 if (!strnicmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
359 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
361 } else if (!strnicmp(str_governor
, "powersave",
363 *policy
= CPUFREQ_POLICY_POWERSAVE
;
366 } else if (cpufreq_driver
->target
) {
367 struct cpufreq_governor
*t
;
369 mutex_lock(&cpufreq_governor_mutex
);
371 t
= __find_governor(str_governor
);
376 mutex_unlock(&cpufreq_governor_mutex
);
377 ret
= request_module("cpufreq_%s", str_governor
);
378 mutex_lock(&cpufreq_governor_mutex
);
381 t
= __find_governor(str_governor
);
389 mutex_unlock(&cpufreq_governor_mutex
);
396 * cpufreq_per_cpu_attr_read() / show_##file_name() -
397 * print out cpufreq information
399 * Write out information from cpufreq_driver->policy[cpu]; object must be
403 #define show_one(file_name, object) \
404 static ssize_t show_##file_name \
405 (struct cpufreq_policy *policy, char *buf) \
407 return sprintf(buf, "%u\n", policy->object); \
410 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
411 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
412 show_one(cpuinfo_transition_latency
, cpuinfo
.transition_latency
);
413 show_one(scaling_min_freq
, min
);
414 show_one(scaling_max_freq
, max
);
415 show_one(scaling_cur_freq
, cur
);
417 static int __cpufreq_set_policy(struct cpufreq_policy
*policy
,
418 struct cpufreq_policy
*new_policy
);
421 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
423 #define store_one(file_name, object) \
424 static ssize_t store_##file_name \
425 (struct cpufreq_policy *policy, const char *buf, size_t count) \
428 struct cpufreq_policy new_policy; \
430 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
434 ret = sscanf(buf, "%u", &new_policy.object); \
438 ret = __cpufreq_set_policy(policy, &new_policy); \
439 policy->user_policy.object = policy->object; \
441 return ret ? ret : count; \
444 store_one(scaling_min_freq
, min
);
445 store_one(scaling_max_freq
, max
);
448 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
450 static ssize_t
show_cpuinfo_cur_freq(struct cpufreq_policy
*policy
,
453 unsigned int cur_freq
= __cpufreq_get(policy
->cpu
);
455 return sprintf(buf
, "<unknown>");
456 return sprintf(buf
, "%u\n", cur_freq
);
460 * show_scaling_governor - show the current policy for the specified CPU
462 static ssize_t
show_scaling_governor(struct cpufreq_policy
*policy
, char *buf
)
464 if (policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
465 return sprintf(buf
, "powersave\n");
466 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
467 return sprintf(buf
, "performance\n");
468 else if (policy
->governor
)
469 return scnprintf(buf
, CPUFREQ_NAME_PLEN
, "%s\n",
470 policy
->governor
->name
);
475 * store_scaling_governor - store policy for the specified CPU
477 static ssize_t
store_scaling_governor(struct cpufreq_policy
*policy
,
478 const char *buf
, size_t count
)
481 char str_governor
[16];
482 struct cpufreq_policy new_policy
;
484 ret
= cpufreq_get_policy(&new_policy
, policy
->cpu
);
488 ret
= sscanf(buf
, "%15s", str_governor
);
492 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
,
493 &new_policy
.governor
))
497 * Do not use cpufreq_set_policy here or the user_policy.max
498 * will be wrongly overridden
500 ret
= __cpufreq_set_policy(policy
, &new_policy
);
502 policy
->user_policy
.policy
= policy
->policy
;
503 policy
->user_policy
.governor
= policy
->governor
;
512 * show_scaling_driver - show the cpufreq driver currently loaded
514 static ssize_t
show_scaling_driver(struct cpufreq_policy
*policy
, char *buf
)
516 return scnprintf(buf
, CPUFREQ_NAME_PLEN
, "%s\n", cpufreq_driver
->name
);
520 * show_scaling_available_governors - show the available CPUfreq governors
522 static ssize_t
show_scaling_available_governors(struct cpufreq_policy
*policy
,
526 struct cpufreq_governor
*t
;
528 if (!cpufreq_driver
->target
) {
529 i
+= sprintf(buf
, "performance powersave");
533 list_for_each_entry(t
, &cpufreq_governor_list
, governor_list
) {
534 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char))
535 - (CPUFREQ_NAME_LEN
+ 2)))
537 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_PLEN
, "%s ", t
->name
);
540 i
+= sprintf(&buf
[i
], "\n");
544 ssize_t
cpufreq_show_cpus(const struct cpumask
*mask
, char *buf
)
549 for_each_cpu(cpu
, mask
) {
551 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
552 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
553 if (i
>= (PAGE_SIZE
- 5))
556 i
+= sprintf(&buf
[i
], "\n");
559 EXPORT_SYMBOL_GPL(cpufreq_show_cpus
);
562 * show_related_cpus - show the CPUs affected by each transition even if
563 * hw coordination is in use
565 static ssize_t
show_related_cpus(struct cpufreq_policy
*policy
, char *buf
)
567 return cpufreq_show_cpus(policy
->related_cpus
, buf
);
571 * show_affected_cpus - show the CPUs affected by each transition
573 static ssize_t
show_affected_cpus(struct cpufreq_policy
*policy
, char *buf
)
575 return cpufreq_show_cpus(policy
->cpus
, buf
);
578 static ssize_t
store_scaling_setspeed(struct cpufreq_policy
*policy
,
579 const char *buf
, size_t count
)
581 unsigned int freq
= 0;
584 if (!policy
->governor
|| !policy
->governor
->store_setspeed
)
587 ret
= sscanf(buf
, "%u", &freq
);
591 policy
->governor
->store_setspeed(policy
, freq
);
596 static ssize_t
show_scaling_setspeed(struct cpufreq_policy
*policy
, char *buf
)
598 if (!policy
->governor
|| !policy
->governor
->show_setspeed
)
599 return sprintf(buf
, "<unsupported>\n");
601 return policy
->governor
->show_setspeed(policy
, buf
);
605 * show_bios_limit - show the current cpufreq HW/BIOS limitation
607 static ssize_t
show_bios_limit(struct cpufreq_policy
*policy
, char *buf
)
611 if (cpufreq_driver
->bios_limit
) {
612 ret
= cpufreq_driver
->bios_limit(policy
->cpu
, &limit
);
614 return sprintf(buf
, "%u\n", limit
);
616 return sprintf(buf
, "%u\n", policy
->cpuinfo
.max_freq
);
619 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq
, 0400);
620 cpufreq_freq_attr_ro(cpuinfo_min_freq
);
621 cpufreq_freq_attr_ro(cpuinfo_max_freq
);
622 cpufreq_freq_attr_ro(cpuinfo_transition_latency
);
623 cpufreq_freq_attr_ro(scaling_available_governors
);
624 cpufreq_freq_attr_ro(scaling_driver
);
625 cpufreq_freq_attr_ro(scaling_cur_freq
);
626 cpufreq_freq_attr_ro(bios_limit
);
627 cpufreq_freq_attr_ro(related_cpus
);
628 cpufreq_freq_attr_ro(affected_cpus
);
629 cpufreq_freq_attr_rw(scaling_min_freq
);
630 cpufreq_freq_attr_rw(scaling_max_freq
);
631 cpufreq_freq_attr_rw(scaling_governor
);
632 cpufreq_freq_attr_rw(scaling_setspeed
);
634 static struct attribute
*default_attrs
[] = {
635 &cpuinfo_min_freq
.attr
,
636 &cpuinfo_max_freq
.attr
,
637 &cpuinfo_transition_latency
.attr
,
638 &scaling_min_freq
.attr
,
639 &scaling_max_freq
.attr
,
642 &scaling_governor
.attr
,
643 &scaling_driver
.attr
,
644 &scaling_available_governors
.attr
,
645 &scaling_setspeed
.attr
,
649 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
650 #define to_attr(a) container_of(a, struct freq_attr, attr)
652 static ssize_t
show(struct kobject
*kobj
, struct attribute
*attr
, char *buf
)
654 struct cpufreq_policy
*policy
= to_policy(kobj
);
655 struct freq_attr
*fattr
= to_attr(attr
);
656 ssize_t ret
= -EINVAL
;
658 if (!down_read_trylock(&cpufreq_rwsem
))
661 if (lock_policy_rwsem_read(policy
->cpu
) < 0)
665 ret
= fattr
->show(policy
, buf
);
669 unlock_policy_rwsem_read(policy
->cpu
);
672 up_read(&cpufreq_rwsem
);
677 static ssize_t
store(struct kobject
*kobj
, struct attribute
*attr
,
678 const char *buf
, size_t count
)
680 struct cpufreq_policy
*policy
= to_policy(kobj
);
681 struct freq_attr
*fattr
= to_attr(attr
);
682 ssize_t ret
= -EINVAL
;
686 if (!cpu_online(policy
->cpu
))
689 if (!down_read_trylock(&cpufreq_rwsem
))
692 if (lock_policy_rwsem_write(policy
->cpu
) < 0)
696 ret
= fattr
->store(policy
, buf
, count
);
700 unlock_policy_rwsem_write(policy
->cpu
);
703 up_read(&cpufreq_rwsem
);
710 static void cpufreq_sysfs_release(struct kobject
*kobj
)
712 struct cpufreq_policy
*policy
= to_policy(kobj
);
713 pr_debug("last reference is dropped\n");
714 complete(&policy
->kobj_unregister
);
717 static const struct sysfs_ops sysfs_ops
= {
722 static struct kobj_type ktype_cpufreq
= {
723 .sysfs_ops
= &sysfs_ops
,
724 .default_attrs
= default_attrs
,
725 .release
= cpufreq_sysfs_release
,
728 struct kobject
*cpufreq_global_kobject
;
729 EXPORT_SYMBOL(cpufreq_global_kobject
);
731 static int cpufreq_global_kobject_usage
;
733 int cpufreq_get_global_kobject(void)
735 if (!cpufreq_global_kobject_usage
++)
736 return kobject_add(cpufreq_global_kobject
,
737 &cpu_subsys
.dev_root
->kobj
, "%s", "cpufreq");
741 EXPORT_SYMBOL(cpufreq_get_global_kobject
);
743 void cpufreq_put_global_kobject(void)
745 if (!--cpufreq_global_kobject_usage
)
746 kobject_del(cpufreq_global_kobject
);
748 EXPORT_SYMBOL(cpufreq_put_global_kobject
);
750 int cpufreq_sysfs_create_file(const struct attribute
*attr
)
752 int ret
= cpufreq_get_global_kobject();
755 ret
= sysfs_create_file(cpufreq_global_kobject
, attr
);
757 cpufreq_put_global_kobject();
762 EXPORT_SYMBOL(cpufreq_sysfs_create_file
);
764 void cpufreq_sysfs_remove_file(const struct attribute
*attr
)
766 sysfs_remove_file(cpufreq_global_kobject
, attr
);
767 cpufreq_put_global_kobject();
769 EXPORT_SYMBOL(cpufreq_sysfs_remove_file
);
771 /* symlink affected CPUs */
772 static int cpufreq_add_dev_symlink(struct cpufreq_policy
*policy
)
777 for_each_cpu(j
, policy
->cpus
) {
778 struct device
*cpu_dev
;
780 if (j
== policy
->cpu
)
783 pr_debug("Adding link for CPU: %u\n", j
);
784 cpu_dev
= get_cpu_device(j
);
785 ret
= sysfs_create_link(&cpu_dev
->kobj
, &policy
->kobj
,
793 static int cpufreq_add_dev_interface(struct cpufreq_policy
*policy
,
796 struct freq_attr
**drv_attr
;
799 /* prepare interface data */
800 ret
= kobject_init_and_add(&policy
->kobj
, &ktype_cpufreq
,
801 &dev
->kobj
, "cpufreq");
805 /* set up files for this cpu device */
806 drv_attr
= cpufreq_driver
->attr
;
807 while ((drv_attr
) && (*drv_attr
)) {
808 ret
= sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
810 goto err_out_kobj_put
;
813 if (cpufreq_driver
->get
) {
814 ret
= sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
816 goto err_out_kobj_put
;
818 if (cpufreq_driver
->target
) {
819 ret
= sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
821 goto err_out_kobj_put
;
823 if (cpufreq_driver
->bios_limit
) {
824 ret
= sysfs_create_file(&policy
->kobj
, &bios_limit
.attr
);
826 goto err_out_kobj_put
;
829 ret
= cpufreq_add_dev_symlink(policy
);
831 goto err_out_kobj_put
;
836 kobject_put(&policy
->kobj
);
837 wait_for_completion(&policy
->kobj_unregister
);
841 static void cpufreq_init_policy(struct cpufreq_policy
*policy
)
843 struct cpufreq_policy new_policy
;
846 memcpy(&new_policy
, policy
, sizeof(*policy
));
847 /* assure that the starting sequence is run in __cpufreq_set_policy */
848 policy
->governor
= NULL
;
850 /* set default policy */
851 ret
= __cpufreq_set_policy(policy
, &new_policy
);
852 policy
->user_policy
.policy
= policy
->policy
;
853 policy
->user_policy
.governor
= policy
->governor
;
856 pr_debug("setting policy failed\n");
857 if (cpufreq_driver
->exit
)
858 cpufreq_driver
->exit(policy
);
862 #ifdef CONFIG_HOTPLUG_CPU
863 static int cpufreq_add_policy_cpu(struct cpufreq_policy
*policy
,
864 unsigned int cpu
, struct device
*dev
,
867 int ret
= 0, has_target
= !!cpufreq_driver
->target
;
871 ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
873 pr_err("%s: Failed to stop governor\n", __func__
);
878 lock_policy_rwsem_write(policy
->cpu
);
880 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
882 cpumask_set_cpu(cpu
, policy
->cpus
);
883 per_cpu(cpufreq_cpu_data
, cpu
) = policy
;
884 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
886 unlock_policy_rwsem_write(policy
->cpu
);
889 if ((ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_START
)) ||
890 (ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
))) {
891 pr_err("%s: Failed to start governor\n", __func__
);
896 /* Don't touch sysfs links during light-weight init */
898 ret
= sysfs_create_link(&dev
->kobj
, &policy
->kobj
, "cpufreq");
904 static struct cpufreq_policy
*cpufreq_policy_restore(unsigned int cpu
)
906 struct cpufreq_policy
*policy
;
909 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
911 policy
= per_cpu(cpufreq_cpu_data_fallback
, cpu
);
913 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
918 static struct cpufreq_policy
*cpufreq_policy_alloc(void)
920 struct cpufreq_policy
*policy
;
922 policy
= kzalloc(sizeof(*policy
), GFP_KERNEL
);
926 if (!alloc_cpumask_var(&policy
->cpus
, GFP_KERNEL
))
927 goto err_free_policy
;
929 if (!zalloc_cpumask_var(&policy
->related_cpus
, GFP_KERNEL
))
930 goto err_free_cpumask
;
932 INIT_LIST_HEAD(&policy
->policy_list
);
936 free_cpumask_var(policy
->cpus
);
943 static void cpufreq_policy_free(struct cpufreq_policy
*policy
)
945 free_cpumask_var(policy
->related_cpus
);
946 free_cpumask_var(policy
->cpus
);
950 static int __cpufreq_add_dev(struct device
*dev
, struct subsys_interface
*sif
,
953 unsigned int j
, cpu
= dev
->id
;
955 struct cpufreq_policy
*policy
;
957 #ifdef CONFIG_HOTPLUG_CPU
958 struct cpufreq_policy
*tpolicy
;
959 struct cpufreq_governor
*gov
;
962 if (cpu_is_offline(cpu
))
965 pr_debug("adding CPU %u\n", cpu
);
968 /* check whether a different CPU already registered this
969 * CPU because it is in the same boat. */
970 policy
= cpufreq_cpu_get(cpu
);
971 if (unlikely(policy
)) {
972 cpufreq_cpu_put(policy
);
977 if (!down_read_trylock(&cpufreq_rwsem
))
980 #ifdef CONFIG_HOTPLUG_CPU
981 /* Check if this cpu was hot-unplugged earlier and has siblings */
982 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
983 list_for_each_entry(tpolicy
, &cpufreq_policy_list
, policy_list
) {
984 if (cpumask_test_cpu(cpu
, tpolicy
->related_cpus
)) {
985 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
986 ret
= cpufreq_add_policy_cpu(tpolicy
, cpu
, dev
, frozen
);
987 up_read(&cpufreq_rwsem
);
991 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
995 /* Restore the saved policy when doing light-weight init */
996 policy
= cpufreq_policy_restore(cpu
);
998 policy
= cpufreq_policy_alloc();
1004 policy
->governor
= CPUFREQ_DEFAULT_GOVERNOR
;
1005 cpumask_copy(policy
->cpus
, cpumask_of(cpu
));
1007 init_completion(&policy
->kobj_unregister
);
1008 INIT_WORK(&policy
->update
, handle_update
);
1010 /* call driver. From then on the cpufreq must be able
1011 * to accept all calls to ->verify and ->setpolicy for this CPU
1013 ret
= cpufreq_driver
->init(policy
);
1015 pr_debug("initialization failed\n");
1016 goto err_set_policy_cpu
;
1019 /* related cpus should atleast have policy->cpus */
1020 cpumask_or(policy
->related_cpus
, policy
->related_cpus
, policy
->cpus
);
1023 * affected cpus must always be the one, which are online. We aren't
1024 * managing offline cpus here.
1026 cpumask_and(policy
->cpus
, policy
->cpus
, cpu_online_mask
);
1028 policy
->user_policy
.min
= policy
->min
;
1029 policy
->user_policy
.max
= policy
->max
;
1031 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1032 CPUFREQ_START
, policy
);
1034 #ifdef CONFIG_HOTPLUG_CPU
1035 gov
= __find_governor(per_cpu(cpufreq_cpu_governor
, cpu
));
1037 policy
->governor
= gov
;
1038 pr_debug("Restoring governor %s for cpu %d\n",
1039 policy
->governor
->name
, cpu
);
1043 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1044 for_each_cpu(j
, policy
->cpus
)
1045 per_cpu(cpufreq_cpu_data
, j
) = policy
;
1046 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1049 ret
= cpufreq_add_dev_interface(policy
, dev
);
1051 goto err_out_unregister
;
1054 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1055 list_add(&policy
->policy_list
, &cpufreq_policy_list
);
1056 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1058 cpufreq_init_policy(policy
);
1060 kobject_uevent(&policy
->kobj
, KOBJ_ADD
);
1061 up_read(&cpufreq_rwsem
);
1063 pr_debug("initialization complete\n");
1068 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1069 for_each_cpu(j
, policy
->cpus
)
1070 per_cpu(cpufreq_cpu_data
, j
) = NULL
;
1071 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1074 cpufreq_policy_free(policy
);
1076 up_read(&cpufreq_rwsem
);
1082 * cpufreq_add_dev - add a CPU device
1084 * Adds the cpufreq interface for a CPU device.
1086 * The Oracle says: try running cpufreq registration/unregistration concurrently
1087 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1088 * mess up, but more thorough testing is needed. - Mathieu
1090 static int cpufreq_add_dev(struct device
*dev
, struct subsys_interface
*sif
)
1092 return __cpufreq_add_dev(dev
, sif
, false);
1095 static void update_policy_cpu(struct cpufreq_policy
*policy
, unsigned int cpu
)
1097 policy
->last_cpu
= policy
->cpu
;
1100 #ifdef CONFIG_CPU_FREQ_TABLE
1101 cpufreq_frequency_table_update_policy_cpu(policy
);
1103 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1104 CPUFREQ_UPDATE_POLICY_CPU
, policy
);
1107 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy
*policy
,
1108 unsigned int old_cpu
, bool frozen
)
1110 struct device
*cpu_dev
;
1113 /* first sibling now owns the new sysfs dir */
1114 cpu_dev
= get_cpu_device(cpumask_first(policy
->cpus
));
1116 /* Don't touch sysfs files during light-weight tear-down */
1120 sysfs_remove_link(&cpu_dev
->kobj
, "cpufreq");
1121 ret
= kobject_move(&policy
->kobj
, &cpu_dev
->kobj
);
1123 pr_err("%s: Failed to move kobj: %d", __func__
, ret
);
1125 WARN_ON(lock_policy_rwsem_write(old_cpu
));
1126 cpumask_set_cpu(old_cpu
, policy
->cpus
);
1127 unlock_policy_rwsem_write(old_cpu
);
1129 ret
= sysfs_create_link(&cpu_dev
->kobj
, &policy
->kobj
,
1138 static int __cpufreq_remove_dev_prepare(struct device
*dev
,
1139 struct subsys_interface
*sif
,
1142 unsigned int cpu
= dev
->id
, cpus
;
1144 unsigned long flags
;
1145 struct cpufreq_policy
*policy
;
1147 pr_debug("%s: unregistering CPU %u\n", __func__
, cpu
);
1149 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1151 policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1153 /* Save the policy somewhere when doing a light-weight tear-down */
1155 per_cpu(cpufreq_cpu_data_fallback
, cpu
) = policy
;
1157 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1160 pr_debug("%s: No cpu_data found\n", __func__
);
1164 if (cpufreq_driver
->target
) {
1165 ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
1167 pr_err("%s: Failed to stop governor\n", __func__
);
1172 #ifdef CONFIG_HOTPLUG_CPU
1173 if (!cpufreq_driver
->setpolicy
)
1174 strncpy(per_cpu(cpufreq_cpu_governor
, cpu
),
1175 policy
->governor
->name
, CPUFREQ_NAME_LEN
);
1178 WARN_ON(lock_policy_rwsem_write(cpu
));
1179 cpus
= cpumask_weight(policy
->cpus
);
1182 cpumask_clear_cpu(cpu
, policy
->cpus
);
1183 unlock_policy_rwsem_write(cpu
);
1185 if (cpu
!= policy
->cpu
&& !frozen
) {
1186 sysfs_remove_link(&dev
->kobj
, "cpufreq");
1187 } else if (cpus
> 1) {
1189 new_cpu
= cpufreq_nominate_new_policy_cpu(policy
, cpu
, frozen
);
1191 WARN_ON(lock_policy_rwsem_write(cpu
));
1192 update_policy_cpu(policy
, new_cpu
);
1193 unlock_policy_rwsem_write(cpu
);
1196 pr_debug("%s: policy Kobject moved to cpu: %d "
1197 "from: %d\n",__func__
, new_cpu
, cpu
);
1205 static int __cpufreq_remove_dev_finish(struct device
*dev
,
1206 struct subsys_interface
*sif
,
1209 unsigned int cpu
= dev
->id
, cpus
;
1211 unsigned long flags
;
1212 struct cpufreq_policy
*policy
;
1213 struct kobject
*kobj
;
1214 struct completion
*cmp
;
1216 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
1217 policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1218 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1221 pr_debug("%s: No cpu_data found\n", __func__
);
1225 lock_policy_rwsem_read(cpu
);
1226 cpus
= cpumask_weight(policy
->cpus
);
1227 unlock_policy_rwsem_read(cpu
);
1229 /* If cpu is last user of policy, free policy */
1231 if (cpufreq_driver
->target
) {
1232 ret
= __cpufreq_governor(policy
,
1233 CPUFREQ_GOV_POLICY_EXIT
);
1235 pr_err("%s: Failed to exit governor\n",
1242 lock_policy_rwsem_read(cpu
);
1243 kobj
= &policy
->kobj
;
1244 cmp
= &policy
->kobj_unregister
;
1245 unlock_policy_rwsem_read(cpu
);
1249 * We need to make sure that the underlying kobj is
1250 * actually not referenced anymore by anybody before we
1251 * proceed with unloading.
1253 pr_debug("waiting for dropping of refcount\n");
1254 wait_for_completion(cmp
);
1255 pr_debug("wait complete\n");
1259 * Perform the ->exit() even during light-weight tear-down,
1260 * since this is a core component, and is essential for the
1261 * subsequent light-weight ->init() to succeed.
1263 if (cpufreq_driver
->exit
)
1264 cpufreq_driver
->exit(policy
);
1266 /* Remove policy from list of active policies */
1267 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1268 list_del(&policy
->policy_list
);
1269 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1272 cpufreq_policy_free(policy
);
1274 if (cpufreq_driver
->target
) {
1275 if ((ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_START
)) ||
1276 (ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
))) {
1277 pr_err("%s: Failed to start governor\n",
1284 per_cpu(cpufreq_cpu_data
, cpu
) = NULL
;
1289 * __cpufreq_remove_dev - remove a CPU device
1291 * Removes the cpufreq interface for a CPU device.
1292 * Caller should already have policy_rwsem in write mode for this CPU.
1293 * This routine frees the rwsem before returning.
1295 static inline int __cpufreq_remove_dev(struct device
*dev
,
1296 struct subsys_interface
*sif
,
1301 ret
= __cpufreq_remove_dev_prepare(dev
, sif
, frozen
);
1304 ret
= __cpufreq_remove_dev_finish(dev
, sif
, frozen
);
1309 static int cpufreq_remove_dev(struct device
*dev
, struct subsys_interface
*sif
)
1311 unsigned int cpu
= dev
->id
;
1314 if (cpu_is_offline(cpu
))
1317 retval
= __cpufreq_remove_dev(dev
, sif
, false);
1321 static void handle_update(struct work_struct
*work
)
1323 struct cpufreq_policy
*policy
=
1324 container_of(work
, struct cpufreq_policy
, update
);
1325 unsigned int cpu
= policy
->cpu
;
1326 pr_debug("handle_update for cpu %u called\n", cpu
);
1327 cpufreq_update_policy(cpu
);
1331 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1334 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1335 * @new_freq: CPU frequency the CPU actually runs at
1337 * We adjust to current frequency first, and need to clean up later.
1338 * So either call to cpufreq_update_policy() or schedule handle_update()).
1340 static void cpufreq_out_of_sync(unsigned int cpu
, unsigned int old_freq
,
1341 unsigned int new_freq
)
1343 struct cpufreq_policy
*policy
;
1344 struct cpufreq_freqs freqs
;
1345 unsigned long flags
;
1347 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1348 "core thinks of %u, is %u kHz.\n", old_freq
, new_freq
);
1350 freqs
.old
= old_freq
;
1351 freqs
.new = new_freq
;
1353 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
1354 policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1355 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1357 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
1358 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
1362 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1365 * This is the last known freq, without actually getting it from the driver.
1366 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1368 unsigned int cpufreq_quick_get(unsigned int cpu
)
1370 struct cpufreq_policy
*policy
;
1371 unsigned int ret_freq
= 0;
1373 if (cpufreq_driver
&& cpufreq_driver
->setpolicy
&& cpufreq_driver
->get
)
1374 return cpufreq_driver
->get(cpu
);
1376 policy
= cpufreq_cpu_get(cpu
);
1378 ret_freq
= policy
->cur
;
1379 cpufreq_cpu_put(policy
);
1384 EXPORT_SYMBOL(cpufreq_quick_get
);
1387 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1390 * Just return the max possible frequency for a given CPU.
1392 unsigned int cpufreq_quick_get_max(unsigned int cpu
)
1394 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1395 unsigned int ret_freq
= 0;
1398 ret_freq
= policy
->max
;
1399 cpufreq_cpu_put(policy
);
1404 EXPORT_SYMBOL(cpufreq_quick_get_max
);
1406 static unsigned int __cpufreq_get(unsigned int cpu
)
1408 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1409 unsigned int ret_freq
= 0;
1411 if (!cpufreq_driver
->get
)
1414 ret_freq
= cpufreq_driver
->get(cpu
);
1416 if (ret_freq
&& policy
->cur
&&
1417 !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1418 /* verify no discrepancy between actual and
1419 saved value exists */
1420 if (unlikely(ret_freq
!= policy
->cur
)) {
1421 cpufreq_out_of_sync(cpu
, policy
->cur
, ret_freq
);
1422 schedule_work(&policy
->update
);
1430 * cpufreq_get - get the current CPU frequency (in kHz)
1433 * Get the CPU current (static) CPU frequency
1435 unsigned int cpufreq_get(unsigned int cpu
)
1437 unsigned int ret_freq
= 0;
1439 if (!down_read_trylock(&cpufreq_rwsem
))
1442 if (unlikely(lock_policy_rwsem_read(cpu
)))
1445 ret_freq
= __cpufreq_get(cpu
);
1447 unlock_policy_rwsem_read(cpu
);
1450 up_read(&cpufreq_rwsem
);
1454 EXPORT_SYMBOL(cpufreq_get
);
1456 static struct subsys_interface cpufreq_interface
= {
1458 .subsys
= &cpu_subsys
,
1459 .add_dev
= cpufreq_add_dev
,
1460 .remove_dev
= cpufreq_remove_dev
,
1464 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1466 * This function is only executed for the boot processor. The other CPUs
1467 * have been put offline by means of CPU hotplug.
1469 static int cpufreq_bp_suspend(void)
1473 int cpu
= smp_processor_id();
1474 struct cpufreq_policy
*policy
;
1476 pr_debug("suspending cpu %u\n", cpu
);
1478 /* If there's no policy for the boot CPU, we have nothing to do. */
1479 policy
= cpufreq_cpu_get(cpu
);
1483 if (cpufreq_driver
->suspend
) {
1484 ret
= cpufreq_driver
->suspend(policy
);
1486 printk(KERN_ERR
"cpufreq: suspend failed in ->suspend "
1487 "step on CPU %u\n", policy
->cpu
);
1490 cpufreq_cpu_put(policy
);
1495 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1497 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1498 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1499 * restored. It will verify that the current freq is in sync with
1500 * what we believe it to be. This is a bit later than when it
1501 * should be, but nonethteless it's better than calling
1502 * cpufreq_driver->get() here which might re-enable interrupts...
1504 * This function is only executed for the boot CPU. The other CPUs have not
1505 * been turned on yet.
1507 static void cpufreq_bp_resume(void)
1511 int cpu
= smp_processor_id();
1512 struct cpufreq_policy
*policy
;
1514 pr_debug("resuming cpu %u\n", cpu
);
1516 /* If there's no policy for the boot CPU, we have nothing to do. */
1517 policy
= cpufreq_cpu_get(cpu
);
1521 if (cpufreq_driver
->resume
) {
1522 ret
= cpufreq_driver
->resume(policy
);
1524 printk(KERN_ERR
"cpufreq: resume failed in ->resume "
1525 "step on CPU %u\n", policy
->cpu
);
1530 schedule_work(&policy
->update
);
1533 cpufreq_cpu_put(policy
);
1536 static struct syscore_ops cpufreq_syscore_ops
= {
1537 .suspend
= cpufreq_bp_suspend
,
1538 .resume
= cpufreq_bp_resume
,
1542 * cpufreq_get_current_driver - return current driver's name
1544 * Return the name string of the currently loaded cpufreq driver
1547 const char *cpufreq_get_current_driver(void)
1550 return cpufreq_driver
->name
;
1554 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver
);
1556 /*********************************************************************
1557 * NOTIFIER LISTS INTERFACE *
1558 *********************************************************************/
1561 * cpufreq_register_notifier - register a driver with cpufreq
1562 * @nb: notifier function to register
1563 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1565 * Add a driver to one of two lists: either a list of drivers that
1566 * are notified about clock rate changes (once before and once after
1567 * the transition), or a list of drivers that are notified about
1568 * changes in cpufreq policy.
1570 * This function may sleep, and has the same return conditions as
1571 * blocking_notifier_chain_register.
1573 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1577 if (cpufreq_disabled())
1580 WARN_ON(!init_cpufreq_transition_notifier_list_called
);
1583 case CPUFREQ_TRANSITION_NOTIFIER
:
1584 ret
= srcu_notifier_chain_register(
1585 &cpufreq_transition_notifier_list
, nb
);
1587 case CPUFREQ_POLICY_NOTIFIER
:
1588 ret
= blocking_notifier_chain_register(
1589 &cpufreq_policy_notifier_list
, nb
);
1597 EXPORT_SYMBOL(cpufreq_register_notifier
);
1600 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1601 * @nb: notifier block to be unregistered
1602 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1604 * Remove a driver from the CPU frequency notifier list.
1606 * This function may sleep, and has the same return conditions as
1607 * blocking_notifier_chain_unregister.
1609 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1613 if (cpufreq_disabled())
1617 case CPUFREQ_TRANSITION_NOTIFIER
:
1618 ret
= srcu_notifier_chain_unregister(
1619 &cpufreq_transition_notifier_list
, nb
);
1621 case CPUFREQ_POLICY_NOTIFIER
:
1622 ret
= blocking_notifier_chain_unregister(
1623 &cpufreq_policy_notifier_list
, nb
);
1631 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1634 /*********************************************************************
1636 *********************************************************************/
1638 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1639 unsigned int target_freq
,
1640 unsigned int relation
)
1642 int retval
= -EINVAL
;
1643 unsigned int old_target_freq
= target_freq
;
1645 if (cpufreq_disabled())
1648 /* Make sure that target_freq is within supported range */
1649 if (target_freq
> policy
->max
)
1650 target_freq
= policy
->max
;
1651 if (target_freq
< policy
->min
)
1652 target_freq
= policy
->min
;
1654 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1655 policy
->cpu
, target_freq
, relation
, old_target_freq
);
1657 if (target_freq
== policy
->cur
)
1660 if (cpufreq_driver
->target
)
1661 retval
= cpufreq_driver
->target(policy
, target_freq
, relation
);
1665 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1667 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1668 unsigned int target_freq
,
1669 unsigned int relation
)
1673 if (unlikely(lock_policy_rwsem_write(policy
->cpu
)))
1676 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1678 unlock_policy_rwsem_write(policy
->cpu
);
1683 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1686 * when "event" is CPUFREQ_GOV_LIMITS
1689 static int __cpufreq_governor(struct cpufreq_policy
*policy
,
1694 /* Only must be defined when default governor is known to have latency
1695 restrictions, like e.g. conservative or ondemand.
1696 That this is the case is already ensured in Kconfig
1698 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1699 struct cpufreq_governor
*gov
= &cpufreq_gov_performance
;
1701 struct cpufreq_governor
*gov
= NULL
;
1704 if (policy
->governor
->max_transition_latency
&&
1705 policy
->cpuinfo
.transition_latency
>
1706 policy
->governor
->max_transition_latency
) {
1710 printk(KERN_WARNING
"%s governor failed, too long"
1711 " transition latency of HW, fallback"
1712 " to %s governor\n",
1713 policy
->governor
->name
,
1715 policy
->governor
= gov
;
1719 if (event
== CPUFREQ_GOV_POLICY_INIT
)
1720 if (!try_module_get(policy
->governor
->owner
))
1723 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1724 policy
->cpu
, event
);
1726 mutex_lock(&cpufreq_governor_lock
);
1727 if ((policy
->governor_enabled
&& event
== CPUFREQ_GOV_START
)
1728 || (!policy
->governor_enabled
1729 && (event
== CPUFREQ_GOV_LIMITS
|| event
== CPUFREQ_GOV_STOP
))) {
1730 mutex_unlock(&cpufreq_governor_lock
);
1734 if (event
== CPUFREQ_GOV_STOP
)
1735 policy
->governor_enabled
= false;
1736 else if (event
== CPUFREQ_GOV_START
)
1737 policy
->governor_enabled
= true;
1739 mutex_unlock(&cpufreq_governor_lock
);
1741 ret
= policy
->governor
->governor(policy
, event
);
1744 if (event
== CPUFREQ_GOV_POLICY_INIT
)
1745 policy
->governor
->initialized
++;
1746 else if (event
== CPUFREQ_GOV_POLICY_EXIT
)
1747 policy
->governor
->initialized
--;
1749 /* Restore original values */
1750 mutex_lock(&cpufreq_governor_lock
);
1751 if (event
== CPUFREQ_GOV_STOP
)
1752 policy
->governor_enabled
= true;
1753 else if (event
== CPUFREQ_GOV_START
)
1754 policy
->governor_enabled
= false;
1755 mutex_unlock(&cpufreq_governor_lock
);
1758 if (((event
== CPUFREQ_GOV_POLICY_INIT
) && ret
) ||
1759 ((event
== CPUFREQ_GOV_POLICY_EXIT
) && !ret
))
1760 module_put(policy
->governor
->owner
);
1765 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1772 if (cpufreq_disabled())
1775 mutex_lock(&cpufreq_governor_mutex
);
1777 governor
->initialized
= 0;
1779 if (__find_governor(governor
->name
) == NULL
) {
1781 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1784 mutex_unlock(&cpufreq_governor_mutex
);
1787 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1789 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1791 #ifdef CONFIG_HOTPLUG_CPU
1798 if (cpufreq_disabled())
1801 #ifdef CONFIG_HOTPLUG_CPU
1802 for_each_present_cpu(cpu
) {
1803 if (cpu_online(cpu
))
1805 if (!strcmp(per_cpu(cpufreq_cpu_governor
, cpu
), governor
->name
))
1806 strcpy(per_cpu(cpufreq_cpu_governor
, cpu
), "\0");
1810 mutex_lock(&cpufreq_governor_mutex
);
1811 list_del(&governor
->governor_list
);
1812 mutex_unlock(&cpufreq_governor_mutex
);
1815 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1818 /*********************************************************************
1819 * POLICY INTERFACE *
1820 *********************************************************************/
1823 * cpufreq_get_policy - get the current cpufreq_policy
1824 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1827 * Reads the current cpufreq policy.
1829 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
1831 struct cpufreq_policy
*cpu_policy
;
1835 cpu_policy
= cpufreq_cpu_get(cpu
);
1839 memcpy(policy
, cpu_policy
, sizeof(*policy
));
1841 cpufreq_cpu_put(cpu_policy
);
1844 EXPORT_SYMBOL(cpufreq_get_policy
);
1847 * data : current policy.
1848 * policy : policy to be set.
1850 static int __cpufreq_set_policy(struct cpufreq_policy
*policy
,
1851 struct cpufreq_policy
*new_policy
)
1853 int ret
= 0, failed
= 1;
1855 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy
->cpu
,
1856 new_policy
->min
, new_policy
->max
);
1858 memcpy(&new_policy
->cpuinfo
, &policy
->cpuinfo
, sizeof(policy
->cpuinfo
));
1860 if (new_policy
->min
> policy
->max
|| new_policy
->max
< policy
->min
) {
1865 /* verify the cpu speed can be set within this limit */
1866 ret
= cpufreq_driver
->verify(new_policy
);
1870 /* adjust if necessary - all reasons */
1871 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1872 CPUFREQ_ADJUST
, new_policy
);
1874 /* adjust if necessary - hardware incompatibility*/
1875 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1876 CPUFREQ_INCOMPATIBLE
, new_policy
);
1879 * verify the cpu speed can be set within this limit, which might be
1880 * different to the first one
1882 ret
= cpufreq_driver
->verify(new_policy
);
1886 /* notification of the new policy */
1887 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1888 CPUFREQ_NOTIFY
, new_policy
);
1890 policy
->min
= new_policy
->min
;
1891 policy
->max
= new_policy
->max
;
1893 pr_debug("new min and max freqs are %u - %u kHz\n",
1894 policy
->min
, policy
->max
);
1896 if (cpufreq_driver
->setpolicy
) {
1897 policy
->policy
= new_policy
->policy
;
1898 pr_debug("setting range\n");
1899 ret
= cpufreq_driver
->setpolicy(new_policy
);
1901 if (new_policy
->governor
!= policy
->governor
) {
1902 /* save old, working values */
1903 struct cpufreq_governor
*old_gov
= policy
->governor
;
1905 pr_debug("governor switch\n");
1907 /* end old governor */
1908 if (policy
->governor
) {
1909 __cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
1910 unlock_policy_rwsem_write(new_policy
->cpu
);
1911 __cpufreq_governor(policy
,
1912 CPUFREQ_GOV_POLICY_EXIT
);
1913 lock_policy_rwsem_write(new_policy
->cpu
);
1916 /* start new governor */
1917 policy
->governor
= new_policy
->governor
;
1918 if (!__cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_INIT
)) {
1919 if (!__cpufreq_governor(policy
, CPUFREQ_GOV_START
)) {
1922 unlock_policy_rwsem_write(new_policy
->cpu
);
1923 __cpufreq_governor(policy
,
1924 CPUFREQ_GOV_POLICY_EXIT
);
1925 lock_policy_rwsem_write(new_policy
->cpu
);
1930 /* new governor failed, so re-start old one */
1931 pr_debug("starting governor %s failed\n",
1932 policy
->governor
->name
);
1934 policy
->governor
= old_gov
;
1935 __cpufreq_governor(policy
,
1936 CPUFREQ_GOV_POLICY_INIT
);
1937 __cpufreq_governor(policy
,
1943 /* might be a policy change, too, so fall through */
1945 pr_debug("governor: change or update limits\n");
1946 ret
= __cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
1954 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1955 * @cpu: CPU which shall be re-evaluated
1957 * Useful for policy notifiers which have different necessities
1958 * at different times.
1960 int cpufreq_update_policy(unsigned int cpu
)
1962 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1963 struct cpufreq_policy new_policy
;
1971 if (unlikely(lock_policy_rwsem_write(cpu
))) {
1976 pr_debug("updating policy for CPU %u\n", cpu
);
1977 memcpy(&new_policy
, policy
, sizeof(*policy
));
1978 new_policy
.min
= policy
->user_policy
.min
;
1979 new_policy
.max
= policy
->user_policy
.max
;
1980 new_policy
.policy
= policy
->user_policy
.policy
;
1981 new_policy
.governor
= policy
->user_policy
.governor
;
1984 * BIOS might change freq behind our back
1985 * -> ask driver for current freq and notify governors about a change
1987 if (cpufreq_driver
->get
) {
1988 new_policy
.cur
= cpufreq_driver
->get(cpu
);
1990 pr_debug("Driver did not initialize current freq");
1991 policy
->cur
= new_policy
.cur
;
1993 if (policy
->cur
!= new_policy
.cur
&& cpufreq_driver
->target
)
1994 cpufreq_out_of_sync(cpu
, policy
->cur
,
1999 ret
= __cpufreq_set_policy(policy
, &new_policy
);
2001 unlock_policy_rwsem_write(cpu
);
2004 cpufreq_cpu_put(policy
);
2008 EXPORT_SYMBOL(cpufreq_update_policy
);
2010 static int cpufreq_cpu_callback(struct notifier_block
*nfb
,
2011 unsigned long action
, void *hcpu
)
2013 unsigned int cpu
= (unsigned long)hcpu
;
2015 bool frozen
= false;
2017 dev
= get_cpu_device(cpu
);
2020 if (action
& CPU_TASKS_FROZEN
)
2023 switch (action
& ~CPU_TASKS_FROZEN
) {
2025 __cpufreq_add_dev(dev
, NULL
, frozen
);
2026 cpufreq_update_policy(cpu
);
2029 case CPU_DOWN_PREPARE
:
2030 __cpufreq_remove_dev_prepare(dev
, NULL
, frozen
);
2034 __cpufreq_remove_dev_finish(dev
, NULL
, frozen
);
2037 case CPU_DOWN_FAILED
:
2038 __cpufreq_add_dev(dev
, NULL
, frozen
);
2045 static struct notifier_block __refdata cpufreq_cpu_notifier
= {
2046 .notifier_call
= cpufreq_cpu_callback
,
2049 /*********************************************************************
2050 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2051 *********************************************************************/
2054 * cpufreq_register_driver - register a CPU Frequency driver
2055 * @driver_data: A struct cpufreq_driver containing the values#
2056 * submitted by the CPU Frequency driver.
2058 * Registers a CPU Frequency driver to this core code. This code
2059 * returns zero on success, -EBUSY when another driver got here first
2060 * (and isn't unregistered in the meantime).
2063 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
2065 unsigned long flags
;
2068 if (cpufreq_disabled())
2071 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
2072 ((!driver_data
->setpolicy
) && (!driver_data
->target
)))
2075 pr_debug("trying to register driver %s\n", driver_data
->name
);
2077 if (driver_data
->setpolicy
)
2078 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
2080 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2081 if (cpufreq_driver
) {
2082 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2085 cpufreq_driver
= driver_data
;
2086 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2088 ret
= subsys_interface_register(&cpufreq_interface
);
2090 goto err_null_driver
;
2092 if (!(cpufreq_driver
->flags
& CPUFREQ_STICKY
)) {
2096 /* check for at least one working CPU */
2097 for (i
= 0; i
< nr_cpu_ids
; i
++)
2098 if (cpu_possible(i
) && per_cpu(cpufreq_cpu_data
, i
)) {
2103 /* if all ->init() calls failed, unregister */
2105 pr_debug("no CPU initialized for driver %s\n",
2111 register_hotcpu_notifier(&cpufreq_cpu_notifier
);
2112 pr_debug("driver %s up and running\n", driver_data
->name
);
2116 subsys_interface_unregister(&cpufreq_interface
);
2118 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2119 cpufreq_driver
= NULL
;
2120 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2123 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
2126 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2128 * Unregister the current CPUFreq driver. Only call this if you have
2129 * the right to do so, i.e. if you have succeeded in initialising before!
2130 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2131 * currently not initialised.
2133 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
2135 unsigned long flags
;
2137 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
))
2140 pr_debug("unregistering driver %s\n", driver
->name
);
2142 subsys_interface_unregister(&cpufreq_interface
);
2143 unregister_hotcpu_notifier(&cpufreq_cpu_notifier
);
2145 down_write(&cpufreq_rwsem
);
2146 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2148 cpufreq_driver
= NULL
;
2150 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2151 up_write(&cpufreq_rwsem
);
2155 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);
2157 static int __init
cpufreq_core_init(void)
2161 if (cpufreq_disabled())
2164 for_each_possible_cpu(cpu
)
2165 init_rwsem(&per_cpu(cpu_policy_rwsem
, cpu
));
2167 cpufreq_global_kobject
= kobject_create();
2168 BUG_ON(!cpufreq_global_kobject
);
2169 register_syscore_ops(&cpufreq_syscore_ops
);
2173 core_initcall(cpufreq_core_init
);