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/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
34 static LIST_HEAD(cpufreq_policy_list
);
36 static inline bool policy_is_inactive(struct cpufreq_policy
*policy
)
38 return cpumask_empty(policy
->cpus
);
41 /* Macros to iterate over CPU policies */
42 #define for_each_suitable_policy(__policy, __active) \
43 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
44 if ((__active) == !policy_is_inactive(__policy))
46 #define for_each_active_policy(__policy) \
47 for_each_suitable_policy(__policy, true)
48 #define for_each_inactive_policy(__policy) \
49 for_each_suitable_policy(__policy, false)
51 #define for_each_policy(__policy) \
52 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
54 /* Iterate over governors */
55 static LIST_HEAD(cpufreq_governor_list
);
56 #define for_each_governor(__governor) \
57 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
60 * The "cpufreq driver" - the arch- or hardware-dependent low
61 * level driver of CPUFreq support, and its spinlock. This lock
62 * also protects the cpufreq_cpu_data array.
64 static struct cpufreq_driver
*cpufreq_driver
;
65 static DEFINE_PER_CPU(struct cpufreq_policy
*, cpufreq_cpu_data
);
66 static DEFINE_RWLOCK(cpufreq_driver_lock
);
68 /* Flag to suspend/resume CPUFreq governors */
69 static bool cpufreq_suspended
;
71 static inline bool has_target(void)
73 return cpufreq_driver
->target_index
|| cpufreq_driver
->target
;
76 /* internal prototypes */
77 static int cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
);
78 static unsigned int __cpufreq_get(struct cpufreq_policy
*policy
);
81 * Two notifier lists: the "policy" list is involved in the
82 * validation process for a new CPU frequency policy; the
83 * "transition" list for kernel code that needs to handle
84 * changes to devices when the CPU clock speed changes.
85 * The mutex locks both lists.
87 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list
);
88 static struct srcu_notifier_head cpufreq_transition_notifier_list
;
90 static bool init_cpufreq_transition_notifier_list_called
;
91 static int __init
init_cpufreq_transition_notifier_list(void)
93 srcu_init_notifier_head(&cpufreq_transition_notifier_list
);
94 init_cpufreq_transition_notifier_list_called
= true;
97 pure_initcall(init_cpufreq_transition_notifier_list
);
99 static int off __read_mostly
;
100 static int cpufreq_disabled(void)
104 void disable_cpufreq(void)
108 static DEFINE_MUTEX(cpufreq_governor_mutex
);
110 bool have_governor_per_policy(void)
112 return !!(cpufreq_driver
->flags
& CPUFREQ_HAVE_GOVERNOR_PER_POLICY
);
114 EXPORT_SYMBOL_GPL(have_governor_per_policy
);
116 struct kobject
*get_governor_parent_kobj(struct cpufreq_policy
*policy
)
118 if (have_governor_per_policy())
119 return &policy
->kobj
;
121 return cpufreq_global_kobject
;
123 EXPORT_SYMBOL_GPL(get_governor_parent_kobj
);
125 struct cpufreq_frequency_table
*cpufreq_frequency_get_table(unsigned int cpu
)
127 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
129 return policy
&& !policy_is_inactive(policy
) ?
130 policy
->freq_table
: NULL
;
132 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table
);
134 static inline u64
get_cpu_idle_time_jiffy(unsigned int cpu
, u64
*wall
)
140 cur_wall_time
= jiffies64_to_cputime64(get_jiffies_64());
142 busy_time
= kcpustat_cpu(cpu
).cpustat
[CPUTIME_USER
];
143 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_SYSTEM
];
144 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_IRQ
];
145 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_SOFTIRQ
];
146 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_STEAL
];
147 busy_time
+= kcpustat_cpu(cpu
).cpustat
[CPUTIME_NICE
];
149 idle_time
= cur_wall_time
- busy_time
;
151 *wall
= cputime_to_usecs(cur_wall_time
);
153 return cputime_to_usecs(idle_time
);
156 u64
get_cpu_idle_time(unsigned int cpu
, u64
*wall
, int io_busy
)
158 u64 idle_time
= get_cpu_idle_time_us(cpu
, io_busy
? wall
: NULL
);
160 if (idle_time
== -1ULL)
161 return get_cpu_idle_time_jiffy(cpu
, wall
);
163 idle_time
+= get_cpu_iowait_time_us(cpu
, wall
);
167 EXPORT_SYMBOL_GPL(get_cpu_idle_time
);
170 * This is a generic cpufreq init() routine which can be used by cpufreq
171 * drivers of SMP systems. It will do following:
172 * - validate & show freq table passed
173 * - set policies transition latency
174 * - policy->cpus with all possible CPUs
176 int cpufreq_generic_init(struct cpufreq_policy
*policy
,
177 struct cpufreq_frequency_table
*table
,
178 unsigned int transition_latency
)
182 ret
= cpufreq_table_validate_and_show(policy
, table
);
184 pr_err("%s: invalid frequency table: %d\n", __func__
, ret
);
188 policy
->cpuinfo
.transition_latency
= transition_latency
;
191 * The driver only supports the SMP configuration where all processors
192 * share the clock and voltage and clock.
194 cpumask_setall(policy
->cpus
);
198 EXPORT_SYMBOL_GPL(cpufreq_generic_init
);
200 struct cpufreq_policy
*cpufreq_cpu_get_raw(unsigned int cpu
)
202 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
204 return policy
&& cpumask_test_cpu(cpu
, policy
->cpus
) ? policy
: NULL
;
206 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw
);
208 unsigned int cpufreq_generic_get(unsigned int cpu
)
210 struct cpufreq_policy
*policy
= cpufreq_cpu_get_raw(cpu
);
212 if (!policy
|| IS_ERR(policy
->clk
)) {
213 pr_err("%s: No %s associated to cpu: %d\n",
214 __func__
, policy
? "clk" : "policy", cpu
);
218 return clk_get_rate(policy
->clk
) / 1000;
220 EXPORT_SYMBOL_GPL(cpufreq_generic_get
);
223 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
225 * @cpu: cpu to find policy for.
227 * This returns policy for 'cpu', returns NULL if it doesn't exist.
228 * It also increments the kobject reference count to mark it busy and so would
229 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
230 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
231 * freed as that depends on the kobj count.
233 * Return: A valid policy on success, otherwise NULL on failure.
235 struct cpufreq_policy
*cpufreq_cpu_get(unsigned int cpu
)
237 struct cpufreq_policy
*policy
= NULL
;
240 if (WARN_ON(cpu
>= nr_cpu_ids
))
243 /* get the cpufreq driver */
244 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
246 if (cpufreq_driver
) {
248 policy
= cpufreq_cpu_get_raw(cpu
);
250 kobject_get(&policy
->kobj
);
253 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
257 EXPORT_SYMBOL_GPL(cpufreq_cpu_get
);
260 * cpufreq_cpu_put: Decrements the usage count of a policy
262 * @policy: policy earlier returned by cpufreq_cpu_get().
264 * This decrements the kobject reference count incremented earlier by calling
267 void cpufreq_cpu_put(struct cpufreq_policy
*policy
)
269 kobject_put(&policy
->kobj
);
271 EXPORT_SYMBOL_GPL(cpufreq_cpu_put
);
273 /*********************************************************************
274 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
275 *********************************************************************/
278 * adjust_jiffies - adjust the system "loops_per_jiffy"
280 * This function alters the system "loops_per_jiffy" for the clock
281 * speed change. Note that loops_per_jiffy cannot be updated on SMP
282 * systems as each CPU might be scaled differently. So, use the arch
283 * per-CPU loops_per_jiffy value wherever possible.
285 static void adjust_jiffies(unsigned long val
, struct cpufreq_freqs
*ci
)
288 static unsigned long l_p_j_ref
;
289 static unsigned int l_p_j_ref_freq
;
291 if (ci
->flags
& CPUFREQ_CONST_LOOPS
)
294 if (!l_p_j_ref_freq
) {
295 l_p_j_ref
= loops_per_jiffy
;
296 l_p_j_ref_freq
= ci
->old
;
297 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
298 l_p_j_ref
, l_p_j_ref_freq
);
300 if (val
== CPUFREQ_POSTCHANGE
&& ci
->old
!= ci
->new) {
301 loops_per_jiffy
= cpufreq_scale(l_p_j_ref
, l_p_j_ref_freq
,
303 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
304 loops_per_jiffy
, ci
->new);
309 static void __cpufreq_notify_transition(struct cpufreq_policy
*policy
,
310 struct cpufreq_freqs
*freqs
, unsigned int state
)
312 BUG_ON(irqs_disabled());
314 if (cpufreq_disabled())
317 freqs
->flags
= cpufreq_driver
->flags
;
318 pr_debug("notification %u of frequency transition to %u kHz\n",
323 case CPUFREQ_PRECHANGE
:
324 /* detect if the driver reported a value as "old frequency"
325 * which is not equal to what the cpufreq core thinks is
328 if (!(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
329 if ((policy
) && (policy
->cpu
== freqs
->cpu
) &&
330 (policy
->cur
) && (policy
->cur
!= freqs
->old
)) {
331 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
332 freqs
->old
, policy
->cur
);
333 freqs
->old
= policy
->cur
;
336 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
337 CPUFREQ_PRECHANGE
, freqs
);
338 adjust_jiffies(CPUFREQ_PRECHANGE
, freqs
);
341 case CPUFREQ_POSTCHANGE
:
342 adjust_jiffies(CPUFREQ_POSTCHANGE
, freqs
);
343 pr_debug("FREQ: %lu - CPU: %lu\n",
344 (unsigned long)freqs
->new, (unsigned long)freqs
->cpu
);
345 trace_cpu_frequency(freqs
->new, freqs
->cpu
);
346 srcu_notifier_call_chain(&cpufreq_transition_notifier_list
,
347 CPUFREQ_POSTCHANGE
, freqs
);
348 if (likely(policy
) && likely(policy
->cpu
== freqs
->cpu
))
349 policy
->cur
= freqs
->new;
355 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
356 * on frequency transition.
358 * This function calls the transition notifiers and the "adjust_jiffies"
359 * function. It is called twice on all CPU frequency changes that have
362 static void cpufreq_notify_transition(struct cpufreq_policy
*policy
,
363 struct cpufreq_freqs
*freqs
, unsigned int state
)
365 for_each_cpu(freqs
->cpu
, policy
->cpus
)
366 __cpufreq_notify_transition(policy
, freqs
, state
);
369 /* Do post notifications when there are chances that transition has failed */
370 static void cpufreq_notify_post_transition(struct cpufreq_policy
*policy
,
371 struct cpufreq_freqs
*freqs
, int transition_failed
)
373 cpufreq_notify_transition(policy
, freqs
, CPUFREQ_POSTCHANGE
);
374 if (!transition_failed
)
377 swap(freqs
->old
, freqs
->new);
378 cpufreq_notify_transition(policy
, freqs
, CPUFREQ_PRECHANGE
);
379 cpufreq_notify_transition(policy
, freqs
, CPUFREQ_POSTCHANGE
);
382 void cpufreq_freq_transition_begin(struct cpufreq_policy
*policy
,
383 struct cpufreq_freqs
*freqs
)
387 * Catch double invocations of _begin() which lead to self-deadlock.
388 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
389 * doesn't invoke _begin() on their behalf, and hence the chances of
390 * double invocations are very low. Moreover, there are scenarios
391 * where these checks can emit false-positive warnings in these
392 * drivers; so we avoid that by skipping them altogether.
394 WARN_ON(!(cpufreq_driver
->flags
& CPUFREQ_ASYNC_NOTIFICATION
)
395 && current
== policy
->transition_task
);
398 wait_event(policy
->transition_wait
, !policy
->transition_ongoing
);
400 spin_lock(&policy
->transition_lock
);
402 if (unlikely(policy
->transition_ongoing
)) {
403 spin_unlock(&policy
->transition_lock
);
407 policy
->transition_ongoing
= true;
408 policy
->transition_task
= current
;
410 spin_unlock(&policy
->transition_lock
);
412 cpufreq_notify_transition(policy
, freqs
, CPUFREQ_PRECHANGE
);
414 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin
);
416 void cpufreq_freq_transition_end(struct cpufreq_policy
*policy
,
417 struct cpufreq_freqs
*freqs
, int transition_failed
)
419 if (unlikely(WARN_ON(!policy
->transition_ongoing
)))
422 cpufreq_notify_post_transition(policy
, freqs
, transition_failed
);
424 policy
->transition_ongoing
= false;
425 policy
->transition_task
= NULL
;
427 wake_up(&policy
->transition_wait
);
429 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end
);
432 /*********************************************************************
434 *********************************************************************/
435 static ssize_t
show_boost(struct kobject
*kobj
,
436 struct attribute
*attr
, char *buf
)
438 return sprintf(buf
, "%d\n", cpufreq_driver
->boost_enabled
);
441 static ssize_t
store_boost(struct kobject
*kobj
, struct attribute
*attr
,
442 const char *buf
, size_t count
)
446 ret
= sscanf(buf
, "%d", &enable
);
447 if (ret
!= 1 || enable
< 0 || enable
> 1)
450 if (cpufreq_boost_trigger_state(enable
)) {
451 pr_err("%s: Cannot %s BOOST!\n",
452 __func__
, enable
? "enable" : "disable");
456 pr_debug("%s: cpufreq BOOST %s\n",
457 __func__
, enable
? "enabled" : "disabled");
461 define_one_global_rw(boost
);
463 static struct cpufreq_governor
*find_governor(const char *str_governor
)
465 struct cpufreq_governor
*t
;
468 if (!strncasecmp(str_governor
, t
->name
, CPUFREQ_NAME_LEN
))
475 * cpufreq_parse_governor - parse a governor string
477 static int cpufreq_parse_governor(char *str_governor
, unsigned int *policy
,
478 struct cpufreq_governor
**governor
)
482 if (cpufreq_driver
->setpolicy
) {
483 if (!strncasecmp(str_governor
, "performance", CPUFREQ_NAME_LEN
)) {
484 *policy
= CPUFREQ_POLICY_PERFORMANCE
;
486 } else if (!strncasecmp(str_governor
, "powersave",
488 *policy
= CPUFREQ_POLICY_POWERSAVE
;
492 struct cpufreq_governor
*t
;
494 mutex_lock(&cpufreq_governor_mutex
);
496 t
= find_governor(str_governor
);
501 mutex_unlock(&cpufreq_governor_mutex
);
502 ret
= request_module("cpufreq_%s", str_governor
);
503 mutex_lock(&cpufreq_governor_mutex
);
506 t
= find_governor(str_governor
);
514 mutex_unlock(&cpufreq_governor_mutex
);
520 * cpufreq_per_cpu_attr_read() / show_##file_name() -
521 * print out cpufreq information
523 * Write out information from cpufreq_driver->policy[cpu]; object must be
527 #define show_one(file_name, object) \
528 static ssize_t show_##file_name \
529 (struct cpufreq_policy *policy, char *buf) \
531 return sprintf(buf, "%u\n", policy->object); \
534 show_one(cpuinfo_min_freq
, cpuinfo
.min_freq
);
535 show_one(cpuinfo_max_freq
, cpuinfo
.max_freq
);
536 show_one(cpuinfo_transition_latency
, cpuinfo
.transition_latency
);
537 show_one(scaling_min_freq
, min
);
538 show_one(scaling_max_freq
, max
);
540 static ssize_t
show_scaling_cur_freq(struct cpufreq_policy
*policy
, char *buf
)
544 if (cpufreq_driver
&& cpufreq_driver
->setpolicy
&& cpufreq_driver
->get
)
545 ret
= sprintf(buf
, "%u\n", cpufreq_driver
->get(policy
->cpu
));
547 ret
= sprintf(buf
, "%u\n", policy
->cur
);
551 static int cpufreq_set_policy(struct cpufreq_policy
*policy
,
552 struct cpufreq_policy
*new_policy
);
555 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
557 #define store_one(file_name, object) \
558 static ssize_t store_##file_name \
559 (struct cpufreq_policy *policy, const char *buf, size_t count) \
562 struct cpufreq_policy new_policy; \
564 memcpy(&new_policy, policy, sizeof(*policy)); \
566 ret = sscanf(buf, "%u", &new_policy.object); \
570 temp = new_policy.object; \
571 ret = cpufreq_set_policy(policy, &new_policy); \
573 policy->user_policy.object = temp; \
575 return ret ? ret : count; \
578 store_one(scaling_min_freq
, min
);
579 store_one(scaling_max_freq
, max
);
582 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
584 static ssize_t
show_cpuinfo_cur_freq(struct cpufreq_policy
*policy
,
587 unsigned int cur_freq
= __cpufreq_get(policy
);
589 return sprintf(buf
, "<unknown>");
590 return sprintf(buf
, "%u\n", cur_freq
);
594 * show_scaling_governor - show the current policy for the specified CPU
596 static ssize_t
show_scaling_governor(struct cpufreq_policy
*policy
, char *buf
)
598 if (policy
->policy
== CPUFREQ_POLICY_POWERSAVE
)
599 return sprintf(buf
, "powersave\n");
600 else if (policy
->policy
== CPUFREQ_POLICY_PERFORMANCE
)
601 return sprintf(buf
, "performance\n");
602 else if (policy
->governor
)
603 return scnprintf(buf
, CPUFREQ_NAME_PLEN
, "%s\n",
604 policy
->governor
->name
);
609 * store_scaling_governor - store policy for the specified CPU
611 static ssize_t
store_scaling_governor(struct cpufreq_policy
*policy
,
612 const char *buf
, size_t count
)
615 char str_governor
[16];
616 struct cpufreq_policy new_policy
;
618 memcpy(&new_policy
, policy
, sizeof(*policy
));
620 ret
= sscanf(buf
, "%15s", str_governor
);
624 if (cpufreq_parse_governor(str_governor
, &new_policy
.policy
,
625 &new_policy
.governor
))
628 ret
= cpufreq_set_policy(policy
, &new_policy
);
629 return ret
? ret
: count
;
633 * show_scaling_driver - show the cpufreq driver currently loaded
635 static ssize_t
show_scaling_driver(struct cpufreq_policy
*policy
, char *buf
)
637 return scnprintf(buf
, CPUFREQ_NAME_PLEN
, "%s\n", cpufreq_driver
->name
);
641 * show_scaling_available_governors - show the available CPUfreq governors
643 static ssize_t
show_scaling_available_governors(struct cpufreq_policy
*policy
,
647 struct cpufreq_governor
*t
;
650 i
+= sprintf(buf
, "performance powersave");
654 for_each_governor(t
) {
655 if (i
>= (ssize_t
) ((PAGE_SIZE
/ sizeof(char))
656 - (CPUFREQ_NAME_LEN
+ 2)))
658 i
+= scnprintf(&buf
[i
], CPUFREQ_NAME_PLEN
, "%s ", t
->name
);
661 i
+= sprintf(&buf
[i
], "\n");
665 ssize_t
cpufreq_show_cpus(const struct cpumask
*mask
, char *buf
)
670 for_each_cpu(cpu
, mask
) {
672 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), " ");
673 i
+= scnprintf(&buf
[i
], (PAGE_SIZE
- i
- 2), "%u", cpu
);
674 if (i
>= (PAGE_SIZE
- 5))
677 i
+= sprintf(&buf
[i
], "\n");
680 EXPORT_SYMBOL_GPL(cpufreq_show_cpus
);
683 * show_related_cpus - show the CPUs affected by each transition even if
684 * hw coordination is in use
686 static ssize_t
show_related_cpus(struct cpufreq_policy
*policy
, char *buf
)
688 return cpufreq_show_cpus(policy
->related_cpus
, buf
);
692 * show_affected_cpus - show the CPUs affected by each transition
694 static ssize_t
show_affected_cpus(struct cpufreq_policy
*policy
, char *buf
)
696 return cpufreq_show_cpus(policy
->cpus
, buf
);
699 static ssize_t
store_scaling_setspeed(struct cpufreq_policy
*policy
,
700 const char *buf
, size_t count
)
702 unsigned int freq
= 0;
705 if (!policy
->governor
|| !policy
->governor
->store_setspeed
)
708 ret
= sscanf(buf
, "%u", &freq
);
712 policy
->governor
->store_setspeed(policy
, freq
);
717 static ssize_t
show_scaling_setspeed(struct cpufreq_policy
*policy
, char *buf
)
719 if (!policy
->governor
|| !policy
->governor
->show_setspeed
)
720 return sprintf(buf
, "<unsupported>\n");
722 return policy
->governor
->show_setspeed(policy
, buf
);
726 * show_bios_limit - show the current cpufreq HW/BIOS limitation
728 static ssize_t
show_bios_limit(struct cpufreq_policy
*policy
, char *buf
)
732 if (cpufreq_driver
->bios_limit
) {
733 ret
= cpufreq_driver
->bios_limit(policy
->cpu
, &limit
);
735 return sprintf(buf
, "%u\n", limit
);
737 return sprintf(buf
, "%u\n", policy
->cpuinfo
.max_freq
);
740 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq
, 0400);
741 cpufreq_freq_attr_ro(cpuinfo_min_freq
);
742 cpufreq_freq_attr_ro(cpuinfo_max_freq
);
743 cpufreq_freq_attr_ro(cpuinfo_transition_latency
);
744 cpufreq_freq_attr_ro(scaling_available_governors
);
745 cpufreq_freq_attr_ro(scaling_driver
);
746 cpufreq_freq_attr_ro(scaling_cur_freq
);
747 cpufreq_freq_attr_ro(bios_limit
);
748 cpufreq_freq_attr_ro(related_cpus
);
749 cpufreq_freq_attr_ro(affected_cpus
);
750 cpufreq_freq_attr_rw(scaling_min_freq
);
751 cpufreq_freq_attr_rw(scaling_max_freq
);
752 cpufreq_freq_attr_rw(scaling_governor
);
753 cpufreq_freq_attr_rw(scaling_setspeed
);
755 static struct attribute
*default_attrs
[] = {
756 &cpuinfo_min_freq
.attr
,
757 &cpuinfo_max_freq
.attr
,
758 &cpuinfo_transition_latency
.attr
,
759 &scaling_min_freq
.attr
,
760 &scaling_max_freq
.attr
,
763 &scaling_governor
.attr
,
764 &scaling_driver
.attr
,
765 &scaling_available_governors
.attr
,
766 &scaling_setspeed
.attr
,
770 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
771 #define to_attr(a) container_of(a, struct freq_attr, attr)
773 static ssize_t
show(struct kobject
*kobj
, struct attribute
*attr
, char *buf
)
775 struct cpufreq_policy
*policy
= to_policy(kobj
);
776 struct freq_attr
*fattr
= to_attr(attr
);
779 down_read(&policy
->rwsem
);
780 ret
= fattr
->show(policy
, buf
);
781 up_read(&policy
->rwsem
);
786 static ssize_t
store(struct kobject
*kobj
, struct attribute
*attr
,
787 const char *buf
, size_t count
)
789 struct cpufreq_policy
*policy
= to_policy(kobj
);
790 struct freq_attr
*fattr
= to_attr(attr
);
791 ssize_t ret
= -EINVAL
;
795 if (cpu_online(policy
->cpu
)) {
796 down_write(&policy
->rwsem
);
797 ret
= fattr
->store(policy
, buf
, count
);
798 up_write(&policy
->rwsem
);
806 static void cpufreq_sysfs_release(struct kobject
*kobj
)
808 struct cpufreq_policy
*policy
= to_policy(kobj
);
809 pr_debug("last reference is dropped\n");
810 complete(&policy
->kobj_unregister
);
813 static const struct sysfs_ops sysfs_ops
= {
818 static struct kobj_type ktype_cpufreq
= {
819 .sysfs_ops
= &sysfs_ops
,
820 .default_attrs
= default_attrs
,
821 .release
= cpufreq_sysfs_release
,
824 static int add_cpu_dev_symlink(struct cpufreq_policy
*policy
, int cpu
)
826 struct device
*cpu_dev
;
828 pr_debug("%s: Adding symlink for CPU: %u\n", __func__
, cpu
);
833 cpu_dev
= get_cpu_device(cpu
);
834 if (WARN_ON(!cpu_dev
))
837 return sysfs_create_link(&cpu_dev
->kobj
, &policy
->kobj
, "cpufreq");
840 static void remove_cpu_dev_symlink(struct cpufreq_policy
*policy
, int cpu
)
842 struct device
*cpu_dev
;
844 pr_debug("%s: Removing symlink for CPU: %u\n", __func__
, cpu
);
846 cpu_dev
= get_cpu_device(cpu
);
847 if (WARN_ON(!cpu_dev
))
850 sysfs_remove_link(&cpu_dev
->kobj
, "cpufreq");
853 /* Add/remove symlinks for all related CPUs */
854 static int cpufreq_add_dev_symlink(struct cpufreq_policy
*policy
)
859 /* Some related CPUs might not be present (physically hotplugged) */
860 for_each_cpu(j
, policy
->real_cpus
) {
861 ret
= add_cpu_dev_symlink(policy
, j
);
869 static void cpufreq_remove_dev_symlink(struct cpufreq_policy
*policy
)
873 /* Some related CPUs might not be present (physically hotplugged) */
874 for_each_cpu(j
, policy
->real_cpus
)
875 remove_cpu_dev_symlink(policy
, j
);
878 static int cpufreq_add_dev_interface(struct cpufreq_policy
*policy
)
880 struct freq_attr
**drv_attr
;
883 /* set up files for this cpu device */
884 drv_attr
= cpufreq_driver
->attr
;
885 while (drv_attr
&& *drv_attr
) {
886 ret
= sysfs_create_file(&policy
->kobj
, &((*drv_attr
)->attr
));
891 if (cpufreq_driver
->get
) {
892 ret
= sysfs_create_file(&policy
->kobj
, &cpuinfo_cur_freq
.attr
);
897 ret
= sysfs_create_file(&policy
->kobj
, &scaling_cur_freq
.attr
);
901 if (cpufreq_driver
->bios_limit
) {
902 ret
= sysfs_create_file(&policy
->kobj
, &bios_limit
.attr
);
907 return cpufreq_add_dev_symlink(policy
);
910 __weak
struct cpufreq_governor
*cpufreq_default_governor(void)
915 static int cpufreq_init_policy(struct cpufreq_policy
*policy
)
917 struct cpufreq_governor
*gov
= NULL
;
918 struct cpufreq_policy new_policy
;
920 memcpy(&new_policy
, policy
, sizeof(*policy
));
922 /* Update governor of new_policy to the governor used before hotplug */
923 gov
= find_governor(policy
->last_governor
);
925 pr_debug("Restoring governor %s for cpu %d\n",
926 policy
->governor
->name
, policy
->cpu
);
928 gov
= cpufreq_default_governor();
933 new_policy
.governor
= gov
;
935 /* Use the default policy if there is no last_policy. */
936 if (cpufreq_driver
->setpolicy
) {
937 if (policy
->last_policy
)
938 new_policy
.policy
= policy
->last_policy
;
940 cpufreq_parse_governor(gov
->name
, &new_policy
.policy
,
943 /* set default policy */
944 return cpufreq_set_policy(policy
, &new_policy
);
947 static int cpufreq_add_policy_cpu(struct cpufreq_policy
*policy
, unsigned int cpu
)
951 /* Has this CPU been taken care of already? */
952 if (cpumask_test_cpu(cpu
, policy
->cpus
))
955 down_write(&policy
->rwsem
);
957 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
959 pr_err("%s: Failed to stop governor\n", __func__
);
964 cpumask_set_cpu(cpu
, policy
->cpus
);
967 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_START
);
969 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
972 pr_err("%s: Failed to start governor\n", __func__
);
976 up_write(&policy
->rwsem
);
980 static void handle_update(struct work_struct
*work
)
982 struct cpufreq_policy
*policy
=
983 container_of(work
, struct cpufreq_policy
, update
);
984 unsigned int cpu
= policy
->cpu
;
985 pr_debug("handle_update for cpu %u called\n", cpu
);
986 cpufreq_update_policy(cpu
);
989 static struct cpufreq_policy
*cpufreq_policy_alloc(unsigned int cpu
)
991 struct device
*dev
= get_cpu_device(cpu
);
992 struct cpufreq_policy
*policy
;
998 policy
= kzalloc(sizeof(*policy
), GFP_KERNEL
);
1002 if (!alloc_cpumask_var(&policy
->cpus
, GFP_KERNEL
))
1003 goto err_free_policy
;
1005 if (!zalloc_cpumask_var(&policy
->related_cpus
, GFP_KERNEL
))
1006 goto err_free_cpumask
;
1008 if (!zalloc_cpumask_var(&policy
->real_cpus
, GFP_KERNEL
))
1009 goto err_free_rcpumask
;
1011 ret
= kobject_init_and_add(&policy
->kobj
, &ktype_cpufreq
,
1012 cpufreq_global_kobject
, "policy%u", cpu
);
1014 pr_err("%s: failed to init policy->kobj: %d\n", __func__
, ret
);
1015 goto err_free_real_cpus
;
1018 INIT_LIST_HEAD(&policy
->policy_list
);
1019 init_rwsem(&policy
->rwsem
);
1020 spin_lock_init(&policy
->transition_lock
);
1021 init_waitqueue_head(&policy
->transition_wait
);
1022 init_completion(&policy
->kobj_unregister
);
1023 INIT_WORK(&policy
->update
, handle_update
);
1029 free_cpumask_var(policy
->real_cpus
);
1031 free_cpumask_var(policy
->related_cpus
);
1033 free_cpumask_var(policy
->cpus
);
1040 static void cpufreq_policy_put_kobj(struct cpufreq_policy
*policy
, bool notify
)
1042 struct kobject
*kobj
;
1043 struct completion
*cmp
;
1046 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1047 CPUFREQ_REMOVE_POLICY
, policy
);
1049 down_write(&policy
->rwsem
);
1050 cpufreq_remove_dev_symlink(policy
);
1051 kobj
= &policy
->kobj
;
1052 cmp
= &policy
->kobj_unregister
;
1053 up_write(&policy
->rwsem
);
1057 * We need to make sure that the underlying kobj is
1058 * actually not referenced anymore by anybody before we
1059 * proceed with unloading.
1061 pr_debug("waiting for dropping of refcount\n");
1062 wait_for_completion(cmp
);
1063 pr_debug("wait complete\n");
1066 static void cpufreq_policy_free(struct cpufreq_policy
*policy
, bool notify
)
1068 unsigned long flags
;
1071 /* Remove policy from list */
1072 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1073 list_del(&policy
->policy_list
);
1075 for_each_cpu(cpu
, policy
->related_cpus
)
1076 per_cpu(cpufreq_cpu_data
, cpu
) = NULL
;
1077 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1079 cpufreq_policy_put_kobj(policy
, notify
);
1080 free_cpumask_var(policy
->real_cpus
);
1081 free_cpumask_var(policy
->related_cpus
);
1082 free_cpumask_var(policy
->cpus
);
1086 static int cpufreq_online(unsigned int cpu
)
1088 struct cpufreq_policy
*policy
;
1090 unsigned long flags
;
1094 pr_debug("%s: bringing CPU%u online\n", __func__
, cpu
);
1096 /* Check if this CPU already has a policy to manage it */
1097 policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1099 WARN_ON(!cpumask_test_cpu(cpu
, policy
->related_cpus
));
1100 if (!policy_is_inactive(policy
))
1101 return cpufreq_add_policy_cpu(policy
, cpu
);
1103 /* This is the only online CPU for the policy. Start over. */
1105 down_write(&policy
->rwsem
);
1107 policy
->governor
= NULL
;
1108 up_write(&policy
->rwsem
);
1111 policy
= cpufreq_policy_alloc(cpu
);
1116 cpumask_copy(policy
->cpus
, cpumask_of(cpu
));
1118 /* call driver. From then on the cpufreq must be able
1119 * to accept all calls to ->verify and ->setpolicy for this CPU
1121 ret
= cpufreq_driver
->init(policy
);
1123 pr_debug("initialization failed\n");
1124 goto out_free_policy
;
1127 down_write(&policy
->rwsem
);
1130 /* related_cpus should at least include policy->cpus. */
1131 cpumask_copy(policy
->related_cpus
, policy
->cpus
);
1132 /* Remember CPUs present at the policy creation time. */
1133 cpumask_and(policy
->real_cpus
, policy
->cpus
, cpu_present_mask
);
1137 * affected cpus must always be the one, which are online. We aren't
1138 * managing offline cpus here.
1140 cpumask_and(policy
->cpus
, policy
->cpus
, cpu_online_mask
);
1143 policy
->user_policy
.min
= policy
->min
;
1144 policy
->user_policy
.max
= policy
->max
;
1146 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1147 for_each_cpu(j
, policy
->related_cpus
)
1148 per_cpu(cpufreq_cpu_data
, j
) = policy
;
1149 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1152 if (cpufreq_driver
->get
&& !cpufreq_driver
->setpolicy
) {
1153 policy
->cur
= cpufreq_driver
->get(policy
->cpu
);
1155 pr_err("%s: ->get() failed\n", __func__
);
1156 goto out_exit_policy
;
1161 * Sometimes boot loaders set CPU frequency to a value outside of
1162 * frequency table present with cpufreq core. In such cases CPU might be
1163 * unstable if it has to run on that frequency for long duration of time
1164 * and so its better to set it to a frequency which is specified in
1165 * freq-table. This also makes cpufreq stats inconsistent as
1166 * cpufreq-stats would fail to register because current frequency of CPU
1167 * isn't found in freq-table.
1169 * Because we don't want this change to effect boot process badly, we go
1170 * for the next freq which is >= policy->cur ('cur' must be set by now,
1171 * otherwise we will end up setting freq to lowest of the table as 'cur'
1172 * is initialized to zero).
1174 * We are passing target-freq as "policy->cur - 1" otherwise
1175 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1176 * equal to target-freq.
1178 if ((cpufreq_driver
->flags
& CPUFREQ_NEED_INITIAL_FREQ_CHECK
)
1180 /* Are we running at unknown frequency ? */
1181 ret
= cpufreq_frequency_table_get_index(policy
, policy
->cur
);
1182 if (ret
== -EINVAL
) {
1183 /* Warn user and fix it */
1184 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1185 __func__
, policy
->cpu
, policy
->cur
);
1186 ret
= __cpufreq_driver_target(policy
, policy
->cur
- 1,
1187 CPUFREQ_RELATION_L
);
1190 * Reaching here after boot in a few seconds may not
1191 * mean that system will remain stable at "unknown"
1192 * frequency for longer duration. Hence, a BUG_ON().
1195 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1196 __func__
, policy
->cpu
, policy
->cur
);
1200 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1201 CPUFREQ_START
, policy
);
1204 ret
= cpufreq_add_dev_interface(policy
);
1206 goto out_exit_policy
;
1207 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
1208 CPUFREQ_CREATE_POLICY
, policy
);
1210 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
1211 list_add(&policy
->policy_list
, &cpufreq_policy_list
);
1212 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1215 ret
= cpufreq_init_policy(policy
);
1217 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1218 __func__
, cpu
, ret
);
1219 /* cpufreq_policy_free() will notify based on this */
1221 goto out_exit_policy
;
1224 up_write(&policy
->rwsem
);
1226 kobject_uevent(&policy
->kobj
, KOBJ_ADD
);
1228 /* Callback for handling stuff after policy is ready */
1229 if (cpufreq_driver
->ready
)
1230 cpufreq_driver
->ready(policy
);
1232 pr_debug("initialization complete\n");
1237 up_write(&policy
->rwsem
);
1239 if (cpufreq_driver
->exit
)
1240 cpufreq_driver
->exit(policy
);
1242 cpufreq_policy_free(policy
, !new_policy
);
1247 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1249 * @sif: Subsystem interface structure pointer (not used)
1251 static int cpufreq_add_dev(struct device
*dev
, struct subsys_interface
*sif
)
1253 unsigned cpu
= dev
->id
;
1256 dev_dbg(dev
, "%s: adding CPU%u\n", __func__
, cpu
);
1258 if (cpu_online(cpu
)) {
1259 ret
= cpufreq_online(cpu
);
1262 * A hotplug notifier will follow and we will handle it as CPU
1263 * online then. For now, just create the sysfs link, unless
1264 * there is no policy or the link is already present.
1266 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1268 ret
= policy
&& !cpumask_test_and_set_cpu(cpu
, policy
->real_cpus
)
1269 ? add_cpu_dev_symlink(policy
, cpu
) : 0;
1275 static void cpufreq_offline(unsigned int cpu
)
1277 struct cpufreq_policy
*policy
;
1280 pr_debug("%s: unregistering CPU %u\n", __func__
, cpu
);
1282 policy
= cpufreq_cpu_get_raw(cpu
);
1284 pr_debug("%s: No cpu_data found\n", __func__
);
1288 down_write(&policy
->rwsem
);
1290 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
1292 pr_err("%s: Failed to stop governor\n", __func__
);
1295 cpumask_clear_cpu(cpu
, policy
->cpus
);
1297 if (policy_is_inactive(policy
)) {
1299 strncpy(policy
->last_governor
, policy
->governor
->name
,
1302 policy
->last_policy
= policy
->policy
;
1303 } else if (cpu
== policy
->cpu
) {
1304 /* Nominate new CPU */
1305 policy
->cpu
= cpumask_any(policy
->cpus
);
1308 /* Start governor again for active policy */
1309 if (!policy_is_inactive(policy
)) {
1311 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_START
);
1313 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
1316 pr_err("%s: Failed to start governor\n", __func__
);
1322 if (cpufreq_driver
->stop_cpu
)
1323 cpufreq_driver
->stop_cpu(policy
);
1325 /* If cpu is last user of policy, free policy */
1327 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_EXIT
);
1329 pr_err("%s: Failed to exit governor\n", __func__
);
1333 * Perform the ->exit() even during light-weight tear-down,
1334 * since this is a core component, and is essential for the
1335 * subsequent light-weight ->init() to succeed.
1337 if (cpufreq_driver
->exit
) {
1338 cpufreq_driver
->exit(policy
);
1339 policy
->freq_table
= NULL
;
1343 up_write(&policy
->rwsem
);
1347 * cpufreq_remove_dev - remove a CPU device
1349 * Removes the cpufreq interface for a CPU device.
1351 static void cpufreq_remove_dev(struct device
*dev
, struct subsys_interface
*sif
)
1353 unsigned int cpu
= dev
->id
;
1354 struct cpufreq_policy
*policy
= per_cpu(cpufreq_cpu_data
, cpu
);
1359 if (cpu_online(cpu
))
1360 cpufreq_offline(cpu
);
1362 cpumask_clear_cpu(cpu
, policy
->real_cpus
);
1363 remove_cpu_dev_symlink(policy
, cpu
);
1365 if (cpumask_empty(policy
->real_cpus
))
1366 cpufreq_policy_free(policy
, true);
1370 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1372 * @policy: policy managing CPUs
1373 * @new_freq: CPU frequency the CPU actually runs at
1375 * We adjust to current frequency first, and need to clean up later.
1376 * So either call to cpufreq_update_policy() or schedule handle_update()).
1378 static void cpufreq_out_of_sync(struct cpufreq_policy
*policy
,
1379 unsigned int new_freq
)
1381 struct cpufreq_freqs freqs
;
1383 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1384 policy
->cur
, new_freq
);
1386 freqs
.old
= policy
->cur
;
1387 freqs
.new = new_freq
;
1389 cpufreq_freq_transition_begin(policy
, &freqs
);
1390 cpufreq_freq_transition_end(policy
, &freqs
, 0);
1394 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1397 * This is the last known freq, without actually getting it from the driver.
1398 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1400 unsigned int cpufreq_quick_get(unsigned int cpu
)
1402 struct cpufreq_policy
*policy
;
1403 unsigned int ret_freq
= 0;
1404 unsigned long flags
;
1406 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
1408 if (cpufreq_driver
&& cpufreq_driver
->setpolicy
&& cpufreq_driver
->get
) {
1409 ret_freq
= cpufreq_driver
->get(cpu
);
1410 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1414 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1416 policy
= cpufreq_cpu_get(cpu
);
1418 ret_freq
= policy
->cur
;
1419 cpufreq_cpu_put(policy
);
1424 EXPORT_SYMBOL(cpufreq_quick_get
);
1427 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1430 * Just return the max possible frequency for a given CPU.
1432 unsigned int cpufreq_quick_get_max(unsigned int cpu
)
1434 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1435 unsigned int ret_freq
= 0;
1438 ret_freq
= policy
->max
;
1439 cpufreq_cpu_put(policy
);
1444 EXPORT_SYMBOL(cpufreq_quick_get_max
);
1446 static unsigned int __cpufreq_get(struct cpufreq_policy
*policy
)
1448 unsigned int ret_freq
= 0;
1450 if (!cpufreq_driver
->get
)
1453 ret_freq
= cpufreq_driver
->get(policy
->cpu
);
1455 /* Updating inactive policies is invalid, so avoid doing that. */
1456 if (unlikely(policy_is_inactive(policy
)))
1459 if (ret_freq
&& policy
->cur
&&
1460 !(cpufreq_driver
->flags
& CPUFREQ_CONST_LOOPS
)) {
1461 /* verify no discrepancy between actual and
1462 saved value exists */
1463 if (unlikely(ret_freq
!= policy
->cur
)) {
1464 cpufreq_out_of_sync(policy
, ret_freq
);
1465 schedule_work(&policy
->update
);
1473 * cpufreq_get - get the current CPU frequency (in kHz)
1476 * Get the CPU current (static) CPU frequency
1478 unsigned int cpufreq_get(unsigned int cpu
)
1480 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
1481 unsigned int ret_freq
= 0;
1484 down_read(&policy
->rwsem
);
1485 ret_freq
= __cpufreq_get(policy
);
1486 up_read(&policy
->rwsem
);
1488 cpufreq_cpu_put(policy
);
1493 EXPORT_SYMBOL(cpufreq_get
);
1495 static struct subsys_interface cpufreq_interface
= {
1497 .subsys
= &cpu_subsys
,
1498 .add_dev
= cpufreq_add_dev
,
1499 .remove_dev
= cpufreq_remove_dev
,
1503 * In case platform wants some specific frequency to be configured
1506 int cpufreq_generic_suspend(struct cpufreq_policy
*policy
)
1510 if (!policy
->suspend_freq
) {
1511 pr_debug("%s: suspend_freq not defined\n", __func__
);
1515 pr_debug("%s: Setting suspend-freq: %u\n", __func__
,
1516 policy
->suspend_freq
);
1518 ret
= __cpufreq_driver_target(policy
, policy
->suspend_freq
,
1519 CPUFREQ_RELATION_H
);
1521 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1522 __func__
, policy
->suspend_freq
, ret
);
1526 EXPORT_SYMBOL(cpufreq_generic_suspend
);
1529 * cpufreq_suspend() - Suspend CPUFreq governors
1531 * Called during system wide Suspend/Hibernate cycles for suspending governors
1532 * as some platforms can't change frequency after this point in suspend cycle.
1533 * Because some of the devices (like: i2c, regulators, etc) they use for
1534 * changing frequency are suspended quickly after this point.
1536 void cpufreq_suspend(void)
1538 struct cpufreq_policy
*policy
;
1541 if (!cpufreq_driver
)
1547 pr_debug("%s: Suspending Governors\n", __func__
);
1549 for_each_active_policy(policy
) {
1550 down_write(&policy
->rwsem
);
1551 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
1552 up_write(&policy
->rwsem
);
1555 pr_err("%s: Failed to stop governor for policy: %p\n",
1557 else if (cpufreq_driver
->suspend
1558 && cpufreq_driver
->suspend(policy
))
1559 pr_err("%s: Failed to suspend driver: %p\n", __func__
,
1564 cpufreq_suspended
= true;
1568 * cpufreq_resume() - Resume CPUFreq governors
1570 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1571 * are suspended with cpufreq_suspend().
1573 void cpufreq_resume(void)
1575 struct cpufreq_policy
*policy
;
1578 if (!cpufreq_driver
)
1581 cpufreq_suspended
= false;
1586 pr_debug("%s: Resuming Governors\n", __func__
);
1588 for_each_active_policy(policy
) {
1589 if (cpufreq_driver
->resume
&& cpufreq_driver
->resume(policy
)) {
1590 pr_err("%s: Failed to resume driver: %p\n", __func__
,
1593 down_write(&policy
->rwsem
);
1594 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_START
);
1596 cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
1597 up_write(&policy
->rwsem
);
1600 pr_err("%s: Failed to start governor for policy: %p\n",
1606 * schedule call cpufreq_update_policy() for first-online CPU, as that
1607 * wouldn't be hotplugged-out on suspend. It will verify that the
1608 * current freq is in sync with what we believe it to be.
1610 policy
= cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask
));
1611 if (WARN_ON(!policy
))
1614 schedule_work(&policy
->update
);
1618 * cpufreq_get_current_driver - return current driver's name
1620 * Return the name string of the currently loaded cpufreq driver
1623 const char *cpufreq_get_current_driver(void)
1626 return cpufreq_driver
->name
;
1630 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver
);
1633 * cpufreq_get_driver_data - return current driver data
1635 * Return the private data of the currently loaded cpufreq
1636 * driver, or NULL if no cpufreq driver is loaded.
1638 void *cpufreq_get_driver_data(void)
1641 return cpufreq_driver
->driver_data
;
1645 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data
);
1647 /*********************************************************************
1648 * NOTIFIER LISTS INTERFACE *
1649 *********************************************************************/
1652 * cpufreq_register_notifier - register a driver with cpufreq
1653 * @nb: notifier function to register
1654 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1656 * Add a driver to one of two lists: either a list of drivers that
1657 * are notified about clock rate changes (once before and once after
1658 * the transition), or a list of drivers that are notified about
1659 * changes in cpufreq policy.
1661 * This function may sleep, and has the same return conditions as
1662 * blocking_notifier_chain_register.
1664 int cpufreq_register_notifier(struct notifier_block
*nb
, unsigned int list
)
1668 if (cpufreq_disabled())
1671 WARN_ON(!init_cpufreq_transition_notifier_list_called
);
1674 case CPUFREQ_TRANSITION_NOTIFIER
:
1675 ret
= srcu_notifier_chain_register(
1676 &cpufreq_transition_notifier_list
, nb
);
1678 case CPUFREQ_POLICY_NOTIFIER
:
1679 ret
= blocking_notifier_chain_register(
1680 &cpufreq_policy_notifier_list
, nb
);
1688 EXPORT_SYMBOL(cpufreq_register_notifier
);
1691 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1692 * @nb: notifier block to be unregistered
1693 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1695 * Remove a driver from the CPU frequency notifier list.
1697 * This function may sleep, and has the same return conditions as
1698 * blocking_notifier_chain_unregister.
1700 int cpufreq_unregister_notifier(struct notifier_block
*nb
, unsigned int list
)
1704 if (cpufreq_disabled())
1708 case CPUFREQ_TRANSITION_NOTIFIER
:
1709 ret
= srcu_notifier_chain_unregister(
1710 &cpufreq_transition_notifier_list
, nb
);
1712 case CPUFREQ_POLICY_NOTIFIER
:
1713 ret
= blocking_notifier_chain_unregister(
1714 &cpufreq_policy_notifier_list
, nb
);
1722 EXPORT_SYMBOL(cpufreq_unregister_notifier
);
1725 /*********************************************************************
1727 *********************************************************************/
1729 /* Must set freqs->new to intermediate frequency */
1730 static int __target_intermediate(struct cpufreq_policy
*policy
,
1731 struct cpufreq_freqs
*freqs
, int index
)
1735 freqs
->new = cpufreq_driver
->get_intermediate(policy
, index
);
1737 /* We don't need to switch to intermediate freq */
1741 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1742 __func__
, policy
->cpu
, freqs
->old
, freqs
->new);
1744 cpufreq_freq_transition_begin(policy
, freqs
);
1745 ret
= cpufreq_driver
->target_intermediate(policy
, index
);
1746 cpufreq_freq_transition_end(policy
, freqs
, ret
);
1749 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1755 static int __target_index(struct cpufreq_policy
*policy
,
1756 struct cpufreq_frequency_table
*freq_table
, int index
)
1758 struct cpufreq_freqs freqs
= {.old
= policy
->cur
, .flags
= 0};
1759 unsigned int intermediate_freq
= 0;
1760 int retval
= -EINVAL
;
1763 notify
= !(cpufreq_driver
->flags
& CPUFREQ_ASYNC_NOTIFICATION
);
1765 /* Handle switching to intermediate frequency */
1766 if (cpufreq_driver
->get_intermediate
) {
1767 retval
= __target_intermediate(policy
, &freqs
, index
);
1771 intermediate_freq
= freqs
.new;
1772 /* Set old freq to intermediate */
1773 if (intermediate_freq
)
1774 freqs
.old
= freqs
.new;
1777 freqs
.new = freq_table
[index
].frequency
;
1778 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1779 __func__
, policy
->cpu
, freqs
.old
, freqs
.new);
1781 cpufreq_freq_transition_begin(policy
, &freqs
);
1784 retval
= cpufreq_driver
->target_index(policy
, index
);
1786 pr_err("%s: Failed to change cpu frequency: %d\n", __func__
,
1790 cpufreq_freq_transition_end(policy
, &freqs
, retval
);
1793 * Failed after setting to intermediate freq? Driver should have
1794 * reverted back to initial frequency and so should we. Check
1795 * here for intermediate_freq instead of get_intermediate, in
1796 * case we haven't switched to intermediate freq at all.
1798 if (unlikely(retval
&& intermediate_freq
)) {
1799 freqs
.old
= intermediate_freq
;
1800 freqs
.new = policy
->restore_freq
;
1801 cpufreq_freq_transition_begin(policy
, &freqs
);
1802 cpufreq_freq_transition_end(policy
, &freqs
, 0);
1809 int __cpufreq_driver_target(struct cpufreq_policy
*policy
,
1810 unsigned int target_freq
,
1811 unsigned int relation
)
1813 unsigned int old_target_freq
= target_freq
;
1814 struct cpufreq_frequency_table
*freq_table
;
1817 if (cpufreq_disabled())
1820 /* Make sure that target_freq is within supported range */
1821 if (target_freq
> policy
->max
)
1822 target_freq
= policy
->max
;
1823 if (target_freq
< policy
->min
)
1824 target_freq
= policy
->min
;
1826 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1827 policy
->cpu
, target_freq
, relation
, old_target_freq
);
1830 * This might look like a redundant call as we are checking it again
1831 * after finding index. But it is left intentionally for cases where
1832 * exactly same freq is called again and so we can save on few function
1835 if (target_freq
== policy
->cur
)
1838 /* Save last value to restore later on errors */
1839 policy
->restore_freq
= policy
->cur
;
1841 if (cpufreq_driver
->target
)
1842 return cpufreq_driver
->target(policy
, target_freq
, relation
);
1844 if (!cpufreq_driver
->target_index
)
1847 freq_table
= cpufreq_frequency_get_table(policy
->cpu
);
1848 if (unlikely(!freq_table
)) {
1849 pr_err("%s: Unable to find freq_table\n", __func__
);
1853 retval
= cpufreq_frequency_table_target(policy
, freq_table
, target_freq
,
1855 if (unlikely(retval
)) {
1856 pr_err("%s: Unable to find matching freq\n", __func__
);
1860 if (freq_table
[index
].frequency
== policy
->cur
)
1863 return __target_index(policy
, freq_table
, index
);
1865 EXPORT_SYMBOL_GPL(__cpufreq_driver_target
);
1867 int cpufreq_driver_target(struct cpufreq_policy
*policy
,
1868 unsigned int target_freq
,
1869 unsigned int relation
)
1873 down_write(&policy
->rwsem
);
1875 ret
= __cpufreq_driver_target(policy
, target_freq
, relation
);
1877 up_write(&policy
->rwsem
);
1881 EXPORT_SYMBOL_GPL(cpufreq_driver_target
);
1883 __weak
struct cpufreq_governor
*cpufreq_fallback_governor(void)
1888 static int cpufreq_governor(struct cpufreq_policy
*policy
, unsigned int event
)
1892 /* Don't start any governor operations if we are entering suspend */
1893 if (cpufreq_suspended
)
1896 * Governor might not be initiated here if ACPI _PPC changed
1897 * notification happened, so check it.
1899 if (!policy
->governor
)
1902 if (policy
->governor
->max_transition_latency
&&
1903 policy
->cpuinfo
.transition_latency
>
1904 policy
->governor
->max_transition_latency
) {
1905 struct cpufreq_governor
*gov
= cpufreq_fallback_governor();
1908 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1909 policy
->governor
->name
, gov
->name
);
1910 policy
->governor
= gov
;
1916 if (event
== CPUFREQ_GOV_POLICY_INIT
)
1917 if (!try_module_get(policy
->governor
->owner
))
1920 pr_debug("%s: for CPU %u, event %u\n", __func__
, policy
->cpu
, event
);
1922 ret
= policy
->governor
->governor(policy
, event
);
1925 if (event
== CPUFREQ_GOV_POLICY_INIT
)
1926 policy
->governor
->initialized
++;
1927 else if (event
== CPUFREQ_GOV_POLICY_EXIT
)
1928 policy
->governor
->initialized
--;
1931 if (((event
== CPUFREQ_GOV_POLICY_INIT
) && ret
) ||
1932 ((event
== CPUFREQ_GOV_POLICY_EXIT
) && !ret
))
1933 module_put(policy
->governor
->owner
);
1938 int cpufreq_register_governor(struct cpufreq_governor
*governor
)
1945 if (cpufreq_disabled())
1948 mutex_lock(&cpufreq_governor_mutex
);
1950 governor
->initialized
= 0;
1952 if (!find_governor(governor
->name
)) {
1954 list_add(&governor
->governor_list
, &cpufreq_governor_list
);
1957 mutex_unlock(&cpufreq_governor_mutex
);
1960 EXPORT_SYMBOL_GPL(cpufreq_register_governor
);
1962 void cpufreq_unregister_governor(struct cpufreq_governor
*governor
)
1964 struct cpufreq_policy
*policy
;
1965 unsigned long flags
;
1970 if (cpufreq_disabled())
1973 /* clear last_governor for all inactive policies */
1974 read_lock_irqsave(&cpufreq_driver_lock
, flags
);
1975 for_each_inactive_policy(policy
) {
1976 if (!strcmp(policy
->last_governor
, governor
->name
)) {
1977 policy
->governor
= NULL
;
1978 strcpy(policy
->last_governor
, "\0");
1981 read_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
1983 mutex_lock(&cpufreq_governor_mutex
);
1984 list_del(&governor
->governor_list
);
1985 mutex_unlock(&cpufreq_governor_mutex
);
1988 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor
);
1991 /*********************************************************************
1992 * POLICY INTERFACE *
1993 *********************************************************************/
1996 * cpufreq_get_policy - get the current cpufreq_policy
1997 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2000 * Reads the current cpufreq policy.
2002 int cpufreq_get_policy(struct cpufreq_policy
*policy
, unsigned int cpu
)
2004 struct cpufreq_policy
*cpu_policy
;
2008 cpu_policy
= cpufreq_cpu_get(cpu
);
2012 memcpy(policy
, cpu_policy
, sizeof(*policy
));
2014 cpufreq_cpu_put(cpu_policy
);
2017 EXPORT_SYMBOL(cpufreq_get_policy
);
2020 * policy : current policy.
2021 * new_policy: policy to be set.
2023 static int cpufreq_set_policy(struct cpufreq_policy
*policy
,
2024 struct cpufreq_policy
*new_policy
)
2026 struct cpufreq_governor
*old_gov
;
2029 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2030 new_policy
->cpu
, new_policy
->min
, new_policy
->max
);
2032 memcpy(&new_policy
->cpuinfo
, &policy
->cpuinfo
, sizeof(policy
->cpuinfo
));
2035 * This check works well when we store new min/max freq attributes,
2036 * because new_policy is a copy of policy with one field updated.
2038 if (new_policy
->min
> new_policy
->max
)
2041 /* verify the cpu speed can be set within this limit */
2042 ret
= cpufreq_driver
->verify(new_policy
);
2046 /* adjust if necessary - all reasons */
2047 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
2048 CPUFREQ_ADJUST
, new_policy
);
2051 * verify the cpu speed can be set within this limit, which might be
2052 * different to the first one
2054 ret
= cpufreq_driver
->verify(new_policy
);
2058 /* notification of the new policy */
2059 blocking_notifier_call_chain(&cpufreq_policy_notifier_list
,
2060 CPUFREQ_NOTIFY
, new_policy
);
2062 policy
->min
= new_policy
->min
;
2063 policy
->max
= new_policy
->max
;
2065 pr_debug("new min and max freqs are %u - %u kHz\n",
2066 policy
->min
, policy
->max
);
2068 if (cpufreq_driver
->setpolicy
) {
2069 policy
->policy
= new_policy
->policy
;
2070 pr_debug("setting range\n");
2071 return cpufreq_driver
->setpolicy(new_policy
);
2074 if (new_policy
->governor
== policy
->governor
)
2077 pr_debug("governor switch\n");
2079 /* save old, working values */
2080 old_gov
= policy
->governor
;
2081 /* end old governor */
2083 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_STOP
);
2085 /* This can happen due to race with other operations */
2086 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2087 __func__
, old_gov
->name
, ret
);
2091 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_EXIT
);
2093 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2094 __func__
, old_gov
->name
, ret
);
2099 /* start new governor */
2100 policy
->governor
= new_policy
->governor
;
2101 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_INIT
);
2103 ret
= cpufreq_governor(policy
, CPUFREQ_GOV_START
);
2107 cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_EXIT
);
2110 /* new governor failed, so re-start old one */
2111 pr_debug("starting governor %s failed\n", policy
->governor
->name
);
2113 policy
->governor
= old_gov
;
2114 if (cpufreq_governor(policy
, CPUFREQ_GOV_POLICY_INIT
))
2115 policy
->governor
= NULL
;
2117 cpufreq_governor(policy
, CPUFREQ_GOV_START
);
2123 pr_debug("governor: change or update limits\n");
2124 return cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
2128 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2129 * @cpu: CPU which shall be re-evaluated
2131 * Useful for policy notifiers which have different necessities
2132 * at different times.
2134 int cpufreq_update_policy(unsigned int cpu
)
2136 struct cpufreq_policy
*policy
= cpufreq_cpu_get(cpu
);
2137 struct cpufreq_policy new_policy
;
2143 down_write(&policy
->rwsem
);
2145 pr_debug("updating policy for CPU %u\n", cpu
);
2146 memcpy(&new_policy
, policy
, sizeof(*policy
));
2147 new_policy
.min
= policy
->user_policy
.min
;
2148 new_policy
.max
= policy
->user_policy
.max
;
2151 * BIOS might change freq behind our back
2152 * -> ask driver for current freq and notify governors about a change
2154 if (cpufreq_driver
->get
&& !cpufreq_driver
->setpolicy
) {
2155 new_policy
.cur
= cpufreq_driver
->get(cpu
);
2156 if (WARN_ON(!new_policy
.cur
)) {
2162 pr_debug("Driver did not initialize current freq\n");
2163 policy
->cur
= new_policy
.cur
;
2165 if (policy
->cur
!= new_policy
.cur
&& has_target())
2166 cpufreq_out_of_sync(policy
, new_policy
.cur
);
2170 ret
= cpufreq_set_policy(policy
, &new_policy
);
2173 up_write(&policy
->rwsem
);
2175 cpufreq_cpu_put(policy
);
2178 EXPORT_SYMBOL(cpufreq_update_policy
);
2180 static int cpufreq_cpu_callback(struct notifier_block
*nfb
,
2181 unsigned long action
, void *hcpu
)
2183 unsigned int cpu
= (unsigned long)hcpu
;
2185 switch (action
& ~CPU_TASKS_FROZEN
) {
2187 cpufreq_online(cpu
);
2190 case CPU_DOWN_PREPARE
:
2191 cpufreq_offline(cpu
);
2194 case CPU_DOWN_FAILED
:
2195 cpufreq_online(cpu
);
2201 static struct notifier_block __refdata cpufreq_cpu_notifier
= {
2202 .notifier_call
= cpufreq_cpu_callback
,
2205 /*********************************************************************
2207 *********************************************************************/
2208 static int cpufreq_boost_set_sw(int state
)
2210 struct cpufreq_frequency_table
*freq_table
;
2211 struct cpufreq_policy
*policy
;
2214 for_each_active_policy(policy
) {
2215 freq_table
= cpufreq_frequency_get_table(policy
->cpu
);
2217 ret
= cpufreq_frequency_table_cpuinfo(policy
,
2220 pr_err("%s: Policy frequency update failed\n",
2225 down_write(&policy
->rwsem
);
2226 policy
->user_policy
.max
= policy
->max
;
2227 cpufreq_governor(policy
, CPUFREQ_GOV_LIMITS
);
2228 up_write(&policy
->rwsem
);
2235 int cpufreq_boost_trigger_state(int state
)
2237 unsigned long flags
;
2240 if (cpufreq_driver
->boost_enabled
== state
)
2243 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2244 cpufreq_driver
->boost_enabled
= state
;
2245 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2247 ret
= cpufreq_driver
->set_boost(state
);
2249 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2250 cpufreq_driver
->boost_enabled
= !state
;
2251 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2253 pr_err("%s: Cannot %s BOOST\n",
2254 __func__
, state
? "enable" : "disable");
2260 static bool cpufreq_boost_supported(void)
2262 return likely(cpufreq_driver
) && cpufreq_driver
->set_boost
;
2265 static int create_boost_sysfs_file(void)
2269 ret
= sysfs_create_file(cpufreq_global_kobject
, &boost
.attr
);
2271 pr_err("%s: cannot register global BOOST sysfs file\n",
2277 static void remove_boost_sysfs_file(void)
2279 if (cpufreq_boost_supported())
2280 sysfs_remove_file(cpufreq_global_kobject
, &boost
.attr
);
2283 int cpufreq_enable_boost_support(void)
2285 if (!cpufreq_driver
)
2288 if (cpufreq_boost_supported())
2291 cpufreq_driver
->set_boost
= cpufreq_boost_set_sw
;
2293 /* This will get removed on driver unregister */
2294 return create_boost_sysfs_file();
2296 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support
);
2298 int cpufreq_boost_enabled(void)
2300 return cpufreq_driver
->boost_enabled
;
2302 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled
);
2304 /*********************************************************************
2305 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2306 *********************************************************************/
2309 * cpufreq_register_driver - register a CPU Frequency driver
2310 * @driver_data: A struct cpufreq_driver containing the values#
2311 * submitted by the CPU Frequency driver.
2313 * Registers a CPU Frequency driver to this core code. This code
2314 * returns zero on success, -EEXIST when another driver got here first
2315 * (and isn't unregistered in the meantime).
2318 int cpufreq_register_driver(struct cpufreq_driver
*driver_data
)
2320 unsigned long flags
;
2323 if (cpufreq_disabled())
2326 if (!driver_data
|| !driver_data
->verify
|| !driver_data
->init
||
2327 !(driver_data
->setpolicy
|| driver_data
->target_index
||
2328 driver_data
->target
) ||
2329 (driver_data
->setpolicy
&& (driver_data
->target_index
||
2330 driver_data
->target
)) ||
2331 (!!driver_data
->get_intermediate
!= !!driver_data
->target_intermediate
))
2334 pr_debug("trying to register driver %s\n", driver_data
->name
);
2336 /* Protect against concurrent CPU online/offline. */
2339 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2340 if (cpufreq_driver
) {
2341 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2345 cpufreq_driver
= driver_data
;
2346 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2348 if (driver_data
->setpolicy
)
2349 driver_data
->flags
|= CPUFREQ_CONST_LOOPS
;
2351 if (cpufreq_boost_supported()) {
2352 ret
= create_boost_sysfs_file();
2354 goto err_null_driver
;
2357 ret
= subsys_interface_register(&cpufreq_interface
);
2359 goto err_boost_unreg
;
2361 if (!(cpufreq_driver
->flags
& CPUFREQ_STICKY
) &&
2362 list_empty(&cpufreq_policy_list
)) {
2363 /* if all ->init() calls failed, unregister */
2364 pr_debug("%s: No CPU initialized for driver %s\n", __func__
,
2369 register_hotcpu_notifier(&cpufreq_cpu_notifier
);
2370 pr_debug("driver %s up and running\n", driver_data
->name
);
2377 subsys_interface_unregister(&cpufreq_interface
);
2379 remove_boost_sysfs_file();
2381 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2382 cpufreq_driver
= NULL
;
2383 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2386 EXPORT_SYMBOL_GPL(cpufreq_register_driver
);
2389 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2391 * Unregister the current CPUFreq driver. Only call this if you have
2392 * the right to do so, i.e. if you have succeeded in initialising before!
2393 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2394 * currently not initialised.
2396 int cpufreq_unregister_driver(struct cpufreq_driver
*driver
)
2398 unsigned long flags
;
2400 if (!cpufreq_driver
|| (driver
!= cpufreq_driver
))
2403 pr_debug("unregistering driver %s\n", driver
->name
);
2405 /* Protect against concurrent cpu hotplug */
2407 subsys_interface_unregister(&cpufreq_interface
);
2408 remove_boost_sysfs_file();
2409 unregister_hotcpu_notifier(&cpufreq_cpu_notifier
);
2411 write_lock_irqsave(&cpufreq_driver_lock
, flags
);
2413 cpufreq_driver
= NULL
;
2415 write_unlock_irqrestore(&cpufreq_driver_lock
, flags
);
2420 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver
);
2423 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2424 * or mutexes when secondary CPUs are halted.
2426 static struct syscore_ops cpufreq_syscore_ops
= {
2427 .shutdown
= cpufreq_suspend
,
2430 struct kobject
*cpufreq_global_kobject
;
2431 EXPORT_SYMBOL(cpufreq_global_kobject
);
2433 static int __init
cpufreq_core_init(void)
2435 if (cpufreq_disabled())
2438 cpufreq_global_kobject
= kobject_create_and_add("cpufreq", &cpu_subsys
.dev_root
->kobj
);
2439 BUG_ON(!cpufreq_global_kobject
);
2441 register_syscore_ops(&cpufreq_syscore_ops
);
2445 core_initcall(cpufreq_core_init
);