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 static bool suitable_policy(struct cpufreq_policy *policy, bool active)
43 return active == !policy_is_inactive(policy);
46 /* Finds Next Acive/Inactive policy */
47 static struct cpufreq_policy *next_policy(struct cpufreq_policy *policy,
51 policy = list_next_entry(policy, policy_list);
53 /* No more policies in the list */
54 if (&policy->policy_list == &cpufreq_policy_list)
56 } while (!suitable_policy(policy, active));
61 static struct cpufreq_policy *first_policy(bool active)
63 struct cpufreq_policy *policy;
65 /* No policies in the list */
66 if (list_empty(&cpufreq_policy_list))
69 policy = list_first_entry(&cpufreq_policy_list, typeof(*policy),
72 if (!suitable_policy(policy, active))
73 policy = next_policy(policy, active);
78 /* Macros to iterate over CPU policies */
79 #define for_each_suitable_policy(__policy, __active) \
80 for (__policy = first_policy(__active); \
82 __policy = next_policy(__policy, __active))
84 #define for_each_active_policy(__policy) \
85 for_each_suitable_policy(__policy, true)
86 #define for_each_inactive_policy(__policy) \
87 for_each_suitable_policy(__policy, false)
89 #define for_each_policy(__policy) \
90 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
92 /* Iterate over governors */
93 static LIST_HEAD(cpufreq_governor_list);
94 #define for_each_governor(__governor) \
95 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
98 * The "cpufreq driver" - the arch- or hardware-dependent low
99 * level driver of CPUFreq support, and its spinlock. This lock
100 * also protects the cpufreq_cpu_data array.
102 static struct cpufreq_driver *cpufreq_driver;
103 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
104 static DEFINE_RWLOCK(cpufreq_driver_lock);
105 DEFINE_MUTEX(cpufreq_governor_lock);
107 /* Flag to suspend/resume CPUFreq governors */
108 static bool cpufreq_suspended;
110 static inline bool has_target(void)
112 return cpufreq_driver->target_index || cpufreq_driver->target;
115 /* internal prototypes */
116 static int __cpufreq_governor(struct cpufreq_policy *policy,
118 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
119 static void handle_update(struct work_struct *work);
122 * Two notifier lists: the "policy" list is involved in the
123 * validation process for a new CPU frequency policy; the
124 * "transition" list for kernel code that needs to handle
125 * changes to devices when the CPU clock speed changes.
126 * The mutex locks both lists.
128 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
129 static struct srcu_notifier_head cpufreq_transition_notifier_list;
131 static bool init_cpufreq_transition_notifier_list_called;
132 static int __init init_cpufreq_transition_notifier_list(void)
134 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
135 init_cpufreq_transition_notifier_list_called = true;
138 pure_initcall(init_cpufreq_transition_notifier_list);
140 static int off __read_mostly;
141 static int cpufreq_disabled(void)
145 void disable_cpufreq(void)
149 static DEFINE_MUTEX(cpufreq_governor_mutex);
151 bool have_governor_per_policy(void)
153 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
155 EXPORT_SYMBOL_GPL(have_governor_per_policy);
157 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
159 if (have_governor_per_policy())
160 return &policy->kobj;
162 return cpufreq_global_kobject;
164 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
166 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
168 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
170 return policy && !policy_is_inactive(policy) ?
171 policy->freq_table : NULL;
173 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
175 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
181 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
183 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
184 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
185 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
186 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
187 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
188 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
190 idle_time = cur_wall_time - busy_time;
192 *wall = cputime_to_usecs(cur_wall_time);
194 return cputime_to_usecs(idle_time);
197 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
199 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
201 if (idle_time == -1ULL)
202 return get_cpu_idle_time_jiffy(cpu, wall);
204 idle_time += get_cpu_iowait_time_us(cpu, wall);
208 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
211 * This is a generic cpufreq init() routine which can be used by cpufreq
212 * drivers of SMP systems. It will do following:
213 * - validate & show freq table passed
214 * - set policies transition latency
215 * - policy->cpus with all possible CPUs
217 int cpufreq_generic_init(struct cpufreq_policy *policy,
218 struct cpufreq_frequency_table *table,
219 unsigned int transition_latency)
223 ret = cpufreq_table_validate_and_show(policy, table);
225 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
229 policy->cpuinfo.transition_latency = transition_latency;
232 * The driver only supports the SMP configuration where all processors
233 * share the clock and voltage and clock.
235 cpumask_setall(policy->cpus);
239 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
241 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
243 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
245 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
247 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
249 unsigned int cpufreq_generic_get(unsigned int cpu)
251 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
253 if (!policy || IS_ERR(policy->clk)) {
254 pr_err("%s: No %s associated to cpu: %d\n",
255 __func__, policy ? "clk" : "policy", cpu);
259 return clk_get_rate(policy->clk) / 1000;
261 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
264 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
266 * @cpu: cpu to find policy for.
268 * This returns policy for 'cpu', returns NULL if it doesn't exist.
269 * It also increments the kobject reference count to mark it busy and so would
270 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
271 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
272 * freed as that depends on the kobj count.
274 * Return: A valid policy on success, otherwise NULL on failure.
276 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
278 struct cpufreq_policy *policy = NULL;
281 if (WARN_ON(cpu >= nr_cpu_ids))
284 /* get the cpufreq driver */
285 read_lock_irqsave(&cpufreq_driver_lock, flags);
287 if (cpufreq_driver) {
289 policy = cpufreq_cpu_get_raw(cpu);
291 kobject_get(&policy->kobj);
294 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
298 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
301 * cpufreq_cpu_put: Decrements the usage count of a policy
303 * @policy: policy earlier returned by cpufreq_cpu_get().
305 * This decrements the kobject reference count incremented earlier by calling
308 void cpufreq_cpu_put(struct cpufreq_policy *policy)
310 kobject_put(&policy->kobj);
312 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
314 /*********************************************************************
315 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
316 *********************************************************************/
319 * adjust_jiffies - adjust the system "loops_per_jiffy"
321 * This function alters the system "loops_per_jiffy" for the clock
322 * speed change. Note that loops_per_jiffy cannot be updated on SMP
323 * systems as each CPU might be scaled differently. So, use the arch
324 * per-CPU loops_per_jiffy value wherever possible.
326 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
329 static unsigned long l_p_j_ref;
330 static unsigned int l_p_j_ref_freq;
332 if (ci->flags & CPUFREQ_CONST_LOOPS)
335 if (!l_p_j_ref_freq) {
336 l_p_j_ref = loops_per_jiffy;
337 l_p_j_ref_freq = ci->old;
338 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
339 l_p_j_ref, l_p_j_ref_freq);
341 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
342 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
344 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
345 loops_per_jiffy, ci->new);
350 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
351 struct cpufreq_freqs *freqs, unsigned int state)
353 BUG_ON(irqs_disabled());
355 if (cpufreq_disabled())
358 freqs->flags = cpufreq_driver->flags;
359 pr_debug("notification %u of frequency transition to %u kHz\n",
364 case CPUFREQ_PRECHANGE:
365 /* detect if the driver reported a value as "old frequency"
366 * which is not equal to what the cpufreq core thinks is
369 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
370 if ((policy) && (policy->cpu == freqs->cpu) &&
371 (policy->cur) && (policy->cur != freqs->old)) {
372 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
373 freqs->old, policy->cur);
374 freqs->old = policy->cur;
377 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
378 CPUFREQ_PRECHANGE, freqs);
379 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
382 case CPUFREQ_POSTCHANGE:
383 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
384 pr_debug("FREQ: %lu - CPU: %lu\n",
385 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
386 trace_cpu_frequency(freqs->new, freqs->cpu);
387 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
388 CPUFREQ_POSTCHANGE, freqs);
389 if (likely(policy) && likely(policy->cpu == freqs->cpu))
390 policy->cur = freqs->new;
396 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
397 * on frequency transition.
399 * This function calls the transition notifiers and the "adjust_jiffies"
400 * function. It is called twice on all CPU frequency changes that have
403 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
404 struct cpufreq_freqs *freqs, unsigned int state)
406 for_each_cpu(freqs->cpu, policy->cpus)
407 __cpufreq_notify_transition(policy, freqs, state);
410 /* Do post notifications when there are chances that transition has failed */
411 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
412 struct cpufreq_freqs *freqs, int transition_failed)
414 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
415 if (!transition_failed)
418 swap(freqs->old, freqs->new);
419 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
420 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
423 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
424 struct cpufreq_freqs *freqs)
428 * Catch double invocations of _begin() which lead to self-deadlock.
429 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
430 * doesn't invoke _begin() on their behalf, and hence the chances of
431 * double invocations are very low. Moreover, there are scenarios
432 * where these checks can emit false-positive warnings in these
433 * drivers; so we avoid that by skipping them altogether.
435 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
436 && current == policy->transition_task);
439 wait_event(policy->transition_wait, !policy->transition_ongoing);
441 spin_lock(&policy->transition_lock);
443 if (unlikely(policy->transition_ongoing)) {
444 spin_unlock(&policy->transition_lock);
448 policy->transition_ongoing = true;
449 policy->transition_task = current;
451 spin_unlock(&policy->transition_lock);
453 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
455 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
457 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
458 struct cpufreq_freqs *freqs, int transition_failed)
460 if (unlikely(WARN_ON(!policy->transition_ongoing)))
463 cpufreq_notify_post_transition(policy, freqs, transition_failed);
465 policy->transition_ongoing = false;
466 policy->transition_task = NULL;
468 wake_up(&policy->transition_wait);
470 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
473 /*********************************************************************
475 *********************************************************************/
476 static ssize_t show_boost(struct kobject *kobj,
477 struct attribute *attr, char *buf)
479 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
482 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
483 const char *buf, size_t count)
487 ret = sscanf(buf, "%d", &enable);
488 if (ret != 1 || enable < 0 || enable > 1)
491 if (cpufreq_boost_trigger_state(enable)) {
492 pr_err("%s: Cannot %s BOOST!\n",
493 __func__, enable ? "enable" : "disable");
497 pr_debug("%s: cpufreq BOOST %s\n",
498 __func__, enable ? "enabled" : "disabled");
502 define_one_global_rw(boost);
504 static struct cpufreq_governor *find_governor(const char *str_governor)
506 struct cpufreq_governor *t;
509 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
516 * cpufreq_parse_governor - parse a governor string
518 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
519 struct cpufreq_governor **governor)
523 if (cpufreq_driver->setpolicy) {
524 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
525 *policy = CPUFREQ_POLICY_PERFORMANCE;
527 } else if (!strncasecmp(str_governor, "powersave",
529 *policy = CPUFREQ_POLICY_POWERSAVE;
533 struct cpufreq_governor *t;
535 mutex_lock(&cpufreq_governor_mutex);
537 t = find_governor(str_governor);
542 mutex_unlock(&cpufreq_governor_mutex);
543 ret = request_module("cpufreq_%s", str_governor);
544 mutex_lock(&cpufreq_governor_mutex);
547 t = find_governor(str_governor);
555 mutex_unlock(&cpufreq_governor_mutex);
561 * cpufreq_per_cpu_attr_read() / show_##file_name() -
562 * print out cpufreq information
564 * Write out information from cpufreq_driver->policy[cpu]; object must be
568 #define show_one(file_name, object) \
569 static ssize_t show_##file_name \
570 (struct cpufreq_policy *policy, char *buf) \
572 return sprintf(buf, "%u\n", policy->object); \
575 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
576 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
577 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
578 show_one(scaling_min_freq, min);
579 show_one(scaling_max_freq, max);
581 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
585 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
586 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
588 ret = sprintf(buf, "%u\n", policy->cur);
592 static int cpufreq_set_policy(struct cpufreq_policy *policy,
593 struct cpufreq_policy *new_policy);
596 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
598 #define store_one(file_name, object) \
599 static ssize_t store_##file_name \
600 (struct cpufreq_policy *policy, const char *buf, size_t count) \
603 struct cpufreq_policy new_policy; \
605 memcpy(&new_policy, policy, sizeof(*policy)); \
607 ret = sscanf(buf, "%u", &new_policy.object); \
611 temp = new_policy.object; \
612 ret = cpufreq_set_policy(policy, &new_policy); \
614 policy->user_policy.object = temp; \
616 return ret ? ret : count; \
619 store_one(scaling_min_freq, min);
620 store_one(scaling_max_freq, max);
623 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
625 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
628 unsigned int cur_freq = __cpufreq_get(policy);
630 return sprintf(buf, "<unknown>");
631 return sprintf(buf, "%u\n", cur_freq);
635 * show_scaling_governor - show the current policy for the specified CPU
637 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
639 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
640 return sprintf(buf, "powersave\n");
641 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
642 return sprintf(buf, "performance\n");
643 else if (policy->governor)
644 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
645 policy->governor->name);
650 * store_scaling_governor - store policy for the specified CPU
652 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
653 const char *buf, size_t count)
656 char str_governor[16];
657 struct cpufreq_policy new_policy;
659 memcpy(&new_policy, policy, sizeof(*policy));
661 ret = sscanf(buf, "%15s", str_governor);
665 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
666 &new_policy.governor))
669 ret = cpufreq_set_policy(policy, &new_policy);
670 return ret ? ret : count;
674 * show_scaling_driver - show the cpufreq driver currently loaded
676 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
678 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
682 * show_scaling_available_governors - show the available CPUfreq governors
684 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
688 struct cpufreq_governor *t;
691 i += sprintf(buf, "performance powersave");
695 for_each_governor(t) {
696 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
697 - (CPUFREQ_NAME_LEN + 2)))
699 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
702 i += sprintf(&buf[i], "\n");
706 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
711 for_each_cpu(cpu, mask) {
713 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
714 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
715 if (i >= (PAGE_SIZE - 5))
718 i += sprintf(&buf[i], "\n");
721 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
724 * show_related_cpus - show the CPUs affected by each transition even if
725 * hw coordination is in use
727 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
729 return cpufreq_show_cpus(policy->related_cpus, buf);
733 * show_affected_cpus - show the CPUs affected by each transition
735 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
737 return cpufreq_show_cpus(policy->cpus, buf);
740 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
741 const char *buf, size_t count)
743 unsigned int freq = 0;
746 if (!policy->governor || !policy->governor->store_setspeed)
749 ret = sscanf(buf, "%u", &freq);
753 policy->governor->store_setspeed(policy, freq);
758 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
760 if (!policy->governor || !policy->governor->show_setspeed)
761 return sprintf(buf, "<unsupported>\n");
763 return policy->governor->show_setspeed(policy, buf);
767 * show_bios_limit - show the current cpufreq HW/BIOS limitation
769 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
773 if (cpufreq_driver->bios_limit) {
774 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
776 return sprintf(buf, "%u\n", limit);
778 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
781 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
782 cpufreq_freq_attr_ro(cpuinfo_min_freq);
783 cpufreq_freq_attr_ro(cpuinfo_max_freq);
784 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
785 cpufreq_freq_attr_ro(scaling_available_governors);
786 cpufreq_freq_attr_ro(scaling_driver);
787 cpufreq_freq_attr_ro(scaling_cur_freq);
788 cpufreq_freq_attr_ro(bios_limit);
789 cpufreq_freq_attr_ro(related_cpus);
790 cpufreq_freq_attr_ro(affected_cpus);
791 cpufreq_freq_attr_rw(scaling_min_freq);
792 cpufreq_freq_attr_rw(scaling_max_freq);
793 cpufreq_freq_attr_rw(scaling_governor);
794 cpufreq_freq_attr_rw(scaling_setspeed);
796 static struct attribute *default_attrs[] = {
797 &cpuinfo_min_freq.attr,
798 &cpuinfo_max_freq.attr,
799 &cpuinfo_transition_latency.attr,
800 &scaling_min_freq.attr,
801 &scaling_max_freq.attr,
804 &scaling_governor.attr,
805 &scaling_driver.attr,
806 &scaling_available_governors.attr,
807 &scaling_setspeed.attr,
811 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
812 #define to_attr(a) container_of(a, struct freq_attr, attr)
814 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
816 struct cpufreq_policy *policy = to_policy(kobj);
817 struct freq_attr *fattr = to_attr(attr);
820 down_read(&policy->rwsem);
823 ret = fattr->show(policy, buf);
827 up_read(&policy->rwsem);
832 static ssize_t store(struct kobject *kobj, struct attribute *attr,
833 const char *buf, size_t count)
835 struct cpufreq_policy *policy = to_policy(kobj);
836 struct freq_attr *fattr = to_attr(attr);
837 ssize_t ret = -EINVAL;
841 if (!cpu_online(policy->cpu))
844 down_write(&policy->rwsem);
847 ret = fattr->store(policy, buf, count);
851 up_write(&policy->rwsem);
858 static void cpufreq_sysfs_release(struct kobject *kobj)
860 struct cpufreq_policy *policy = to_policy(kobj);
861 pr_debug("last reference is dropped\n");
862 complete(&policy->kobj_unregister);
865 static const struct sysfs_ops sysfs_ops = {
870 static struct kobj_type ktype_cpufreq = {
871 .sysfs_ops = &sysfs_ops,
872 .default_attrs = default_attrs,
873 .release = cpufreq_sysfs_release,
876 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
878 struct device *cpu_dev;
880 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
885 cpu_dev = get_cpu_device(cpu);
886 if (WARN_ON(!cpu_dev))
889 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
892 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
894 struct device *cpu_dev;
896 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
898 cpu_dev = get_cpu_device(cpu);
899 if (WARN_ON(!cpu_dev))
902 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
905 /* Add/remove symlinks for all related CPUs */
906 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
911 /* Some related CPUs might not be present (physically hotplugged) */
912 for_each_cpu(j, policy->real_cpus) {
913 ret = add_cpu_dev_symlink(policy, j);
921 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
925 /* Some related CPUs might not be present (physically hotplugged) */
926 for_each_cpu(j, policy->real_cpus)
927 remove_cpu_dev_symlink(policy, j);
930 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
932 struct freq_attr **drv_attr;
935 /* set up files for this cpu device */
936 drv_attr = cpufreq_driver->attr;
937 while (drv_attr && *drv_attr) {
938 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
943 if (cpufreq_driver->get) {
944 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
949 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
953 if (cpufreq_driver->bios_limit) {
954 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
959 return cpufreq_add_dev_symlink(policy);
962 static int cpufreq_init_policy(struct cpufreq_policy *policy)
964 struct cpufreq_governor *gov = NULL;
965 struct cpufreq_policy new_policy;
967 memcpy(&new_policy, policy, sizeof(*policy));
969 /* Update governor of new_policy to the governor used before hotplug */
970 gov = find_governor(policy->last_governor);
972 pr_debug("Restoring governor %s for cpu %d\n",
973 policy->governor->name, policy->cpu);
975 gov = CPUFREQ_DEFAULT_GOVERNOR;
977 new_policy.governor = gov;
979 /* Use the default policy if its valid. */
980 if (cpufreq_driver->setpolicy)
981 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
983 /* set default policy */
984 return cpufreq_set_policy(policy, &new_policy);
987 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
991 /* Has this CPU been taken care of already? */
992 if (cpumask_test_cpu(cpu, policy->cpus))
996 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
998 pr_err("%s: Failed to stop governor\n", __func__);
1003 down_write(&policy->rwsem);
1004 cpumask_set_cpu(cpu, policy->cpus);
1005 up_write(&policy->rwsem);
1008 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1010 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1013 pr_err("%s: Failed to start governor\n", __func__);
1021 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1023 struct device *dev = get_cpu_device(cpu);
1024 struct cpufreq_policy *policy;
1029 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1033 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1034 goto err_free_policy;
1036 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1037 goto err_free_cpumask;
1039 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1040 goto err_free_rcpumask;
1042 kobject_init(&policy->kobj, &ktype_cpufreq);
1043 INIT_LIST_HEAD(&policy->policy_list);
1044 init_rwsem(&policy->rwsem);
1045 spin_lock_init(&policy->transition_lock);
1046 init_waitqueue_head(&policy->transition_wait);
1047 init_completion(&policy->kobj_unregister);
1048 INIT_WORK(&policy->update, handle_update);
1054 free_cpumask_var(policy->related_cpus);
1056 free_cpumask_var(policy->cpus);
1063 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1065 struct kobject *kobj;
1066 struct completion *cmp;
1069 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1070 CPUFREQ_REMOVE_POLICY, policy);
1072 down_write(&policy->rwsem);
1073 cpufreq_remove_dev_symlink(policy);
1074 kobj = &policy->kobj;
1075 cmp = &policy->kobj_unregister;
1076 up_write(&policy->rwsem);
1080 * We need to make sure that the underlying kobj is
1081 * actually not referenced anymore by anybody before we
1082 * proceed with unloading.
1084 pr_debug("waiting for dropping of refcount\n");
1085 wait_for_completion(cmp);
1086 pr_debug("wait complete\n");
1089 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1091 unsigned long flags;
1094 /* Remove policy from list */
1095 write_lock_irqsave(&cpufreq_driver_lock, flags);
1096 list_del(&policy->policy_list);
1098 for_each_cpu(cpu, policy->related_cpus)
1099 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1100 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1102 cpufreq_policy_put_kobj(policy, notify);
1103 free_cpumask_var(policy->real_cpus);
1104 free_cpumask_var(policy->related_cpus);
1105 free_cpumask_var(policy->cpus);
1109 static int cpufreq_online(unsigned int cpu)
1111 struct cpufreq_policy *policy;
1113 unsigned long flags;
1117 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1119 /* Check if this CPU already has a policy to manage it */
1120 policy = per_cpu(cpufreq_cpu_data, cpu);
1122 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1123 if (!policy_is_inactive(policy))
1124 return cpufreq_add_policy_cpu(policy, cpu);
1126 /* This is the only online CPU for the policy. Start over. */
1128 down_write(&policy->rwsem);
1130 policy->governor = NULL;
1131 up_write(&policy->rwsem);
1134 policy = cpufreq_policy_alloc(cpu);
1139 cpumask_copy(policy->cpus, cpumask_of(cpu));
1141 /* call driver. From then on the cpufreq must be able
1142 * to accept all calls to ->verify and ->setpolicy for this CPU
1144 ret = cpufreq_driver->init(policy);
1146 pr_debug("initialization failed\n");
1147 goto out_free_policy;
1150 down_write(&policy->rwsem);
1153 /* related_cpus should at least include policy->cpus. */
1154 cpumask_copy(policy->related_cpus, policy->cpus);
1155 /* Remember CPUs present at the policy creation time. */
1156 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1158 /* Name and add the kobject */
1159 ret = kobject_add(&policy->kobj, cpufreq_global_kobject,
1161 cpumask_first(policy->related_cpus));
1163 pr_err("%s: failed to add policy->kobj: %d\n", __func__,
1165 goto out_exit_policy;
1170 * affected cpus must always be the one, which are online. We aren't
1171 * managing offline cpus here.
1173 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1176 policy->user_policy.min = policy->min;
1177 policy->user_policy.max = policy->max;
1179 write_lock_irqsave(&cpufreq_driver_lock, flags);
1180 for_each_cpu(j, policy->related_cpus)
1181 per_cpu(cpufreq_cpu_data, j) = policy;
1182 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1185 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1186 policy->cur = cpufreq_driver->get(policy->cpu);
1188 pr_err("%s: ->get() failed\n", __func__);
1189 goto out_exit_policy;
1194 * Sometimes boot loaders set CPU frequency to a value outside of
1195 * frequency table present with cpufreq core. In such cases CPU might be
1196 * unstable if it has to run on that frequency for long duration of time
1197 * and so its better to set it to a frequency which is specified in
1198 * freq-table. This also makes cpufreq stats inconsistent as
1199 * cpufreq-stats would fail to register because current frequency of CPU
1200 * isn't found in freq-table.
1202 * Because we don't want this change to effect boot process badly, we go
1203 * for the next freq which is >= policy->cur ('cur' must be set by now,
1204 * otherwise we will end up setting freq to lowest of the table as 'cur'
1205 * is initialized to zero).
1207 * We are passing target-freq as "policy->cur - 1" otherwise
1208 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1209 * equal to target-freq.
1211 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1213 /* Are we running at unknown frequency ? */
1214 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1215 if (ret == -EINVAL) {
1216 /* Warn user and fix it */
1217 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1218 __func__, policy->cpu, policy->cur);
1219 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1220 CPUFREQ_RELATION_L);
1223 * Reaching here after boot in a few seconds may not
1224 * mean that system will remain stable at "unknown"
1225 * frequency for longer duration. Hence, a BUG_ON().
1228 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1229 __func__, policy->cpu, policy->cur);
1233 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1234 CPUFREQ_START, policy);
1237 ret = cpufreq_add_dev_interface(policy);
1239 goto out_exit_policy;
1240 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1241 CPUFREQ_CREATE_POLICY, policy);
1243 write_lock_irqsave(&cpufreq_driver_lock, flags);
1244 list_add(&policy->policy_list, &cpufreq_policy_list);
1245 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1248 ret = cpufreq_init_policy(policy);
1250 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1251 __func__, cpu, ret);
1252 /* cpufreq_policy_free() will notify based on this */
1254 goto out_exit_policy;
1257 up_write(&policy->rwsem);
1259 kobject_uevent(&policy->kobj, KOBJ_ADD);
1261 /* Callback for handling stuff after policy is ready */
1262 if (cpufreq_driver->ready)
1263 cpufreq_driver->ready(policy);
1265 pr_debug("initialization complete\n");
1270 up_write(&policy->rwsem);
1272 if (cpufreq_driver->exit)
1273 cpufreq_driver->exit(policy);
1275 cpufreq_policy_free(policy, !new_policy);
1280 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1282 * @sif: Subsystem interface structure pointer (not used)
1284 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1286 unsigned cpu = dev->id;
1289 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1291 if (cpu_online(cpu)) {
1292 ret = cpufreq_online(cpu);
1295 * A hotplug notifier will follow and we will handle it as CPU
1296 * online then. For now, just create the sysfs link, unless
1297 * there is no policy or the link is already present.
1299 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1301 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1302 ? add_cpu_dev_symlink(policy, cpu) : 0;
1308 static void cpufreq_offline_prepare(unsigned int cpu)
1310 struct cpufreq_policy *policy;
1312 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1314 policy = cpufreq_cpu_get_raw(cpu);
1316 pr_debug("%s: No cpu_data found\n", __func__);
1321 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1323 pr_err("%s: Failed to stop governor\n", __func__);
1326 down_write(&policy->rwsem);
1327 cpumask_clear_cpu(cpu, policy->cpus);
1329 if (policy_is_inactive(policy)) {
1331 strncpy(policy->last_governor, policy->governor->name,
1333 } else if (cpu == policy->cpu) {
1334 /* Nominate new CPU */
1335 policy->cpu = cpumask_any(policy->cpus);
1337 up_write(&policy->rwsem);
1339 /* Start governor again for active policy */
1340 if (!policy_is_inactive(policy)) {
1342 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1344 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1347 pr_err("%s: Failed to start governor\n", __func__);
1349 } else if (cpufreq_driver->stop_cpu) {
1350 cpufreq_driver->stop_cpu(policy);
1354 static void cpufreq_offline_finish(unsigned int cpu)
1356 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1359 pr_debug("%s: No cpu_data found\n", __func__);
1363 /* Only proceed for inactive policies */
1364 if (!policy_is_inactive(policy))
1367 /* If cpu is last user of policy, free policy */
1369 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1371 pr_err("%s: Failed to exit governor\n", __func__);
1375 * Perform the ->exit() even during light-weight tear-down,
1376 * since this is a core component, and is essential for the
1377 * subsequent light-weight ->init() to succeed.
1379 if (cpufreq_driver->exit) {
1380 cpufreq_driver->exit(policy);
1381 policy->freq_table = NULL;
1386 * cpufreq_remove_dev - remove a CPU device
1388 * Removes the cpufreq interface for a CPU device.
1390 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1392 unsigned int cpu = dev->id;
1393 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1398 if (cpu_online(cpu)) {
1399 cpufreq_offline_prepare(cpu);
1400 cpufreq_offline_finish(cpu);
1403 cpumask_clear_cpu(cpu, policy->real_cpus);
1404 remove_cpu_dev_symlink(policy, cpu);
1406 if (cpumask_empty(policy->real_cpus))
1407 cpufreq_policy_free(policy, true);
1410 static void handle_update(struct work_struct *work)
1412 struct cpufreq_policy *policy =
1413 container_of(work, struct cpufreq_policy, update);
1414 unsigned int cpu = policy->cpu;
1415 pr_debug("handle_update for cpu %u called\n", cpu);
1416 cpufreq_update_policy(cpu);
1420 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1422 * @policy: policy managing CPUs
1423 * @new_freq: CPU frequency the CPU actually runs at
1425 * We adjust to current frequency first, and need to clean up later.
1426 * So either call to cpufreq_update_policy() or schedule handle_update()).
1428 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1429 unsigned int new_freq)
1431 struct cpufreq_freqs freqs;
1433 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1434 policy->cur, new_freq);
1436 freqs.old = policy->cur;
1437 freqs.new = new_freq;
1439 cpufreq_freq_transition_begin(policy, &freqs);
1440 cpufreq_freq_transition_end(policy, &freqs, 0);
1444 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1447 * This is the last known freq, without actually getting it from the driver.
1448 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1450 unsigned int cpufreq_quick_get(unsigned int cpu)
1452 struct cpufreq_policy *policy;
1453 unsigned int ret_freq = 0;
1455 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1456 return cpufreq_driver->get(cpu);
1458 policy = cpufreq_cpu_get(cpu);
1460 ret_freq = policy->cur;
1461 cpufreq_cpu_put(policy);
1466 EXPORT_SYMBOL(cpufreq_quick_get);
1469 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1472 * Just return the max possible frequency for a given CPU.
1474 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1476 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1477 unsigned int ret_freq = 0;
1480 ret_freq = policy->max;
1481 cpufreq_cpu_put(policy);
1486 EXPORT_SYMBOL(cpufreq_quick_get_max);
1488 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1490 unsigned int ret_freq = 0;
1492 if (!cpufreq_driver->get)
1495 ret_freq = cpufreq_driver->get(policy->cpu);
1497 /* Updating inactive policies is invalid, so avoid doing that. */
1498 if (unlikely(policy_is_inactive(policy)))
1501 if (ret_freq && policy->cur &&
1502 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1503 /* verify no discrepancy between actual and
1504 saved value exists */
1505 if (unlikely(ret_freq != policy->cur)) {
1506 cpufreq_out_of_sync(policy, ret_freq);
1507 schedule_work(&policy->update);
1515 * cpufreq_get - get the current CPU frequency (in kHz)
1518 * Get the CPU current (static) CPU frequency
1520 unsigned int cpufreq_get(unsigned int cpu)
1522 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1523 unsigned int ret_freq = 0;
1526 down_read(&policy->rwsem);
1527 ret_freq = __cpufreq_get(policy);
1528 up_read(&policy->rwsem);
1530 cpufreq_cpu_put(policy);
1535 EXPORT_SYMBOL(cpufreq_get);
1537 static struct subsys_interface cpufreq_interface = {
1539 .subsys = &cpu_subsys,
1540 .add_dev = cpufreq_add_dev,
1541 .remove_dev = cpufreq_remove_dev,
1545 * In case platform wants some specific frequency to be configured
1548 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1552 if (!policy->suspend_freq) {
1553 pr_debug("%s: suspend_freq not defined\n", __func__);
1557 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1558 policy->suspend_freq);
1560 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1561 CPUFREQ_RELATION_H);
1563 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1564 __func__, policy->suspend_freq, ret);
1568 EXPORT_SYMBOL(cpufreq_generic_suspend);
1571 * cpufreq_suspend() - Suspend CPUFreq governors
1573 * Called during system wide Suspend/Hibernate cycles for suspending governors
1574 * as some platforms can't change frequency after this point in suspend cycle.
1575 * Because some of the devices (like: i2c, regulators, etc) they use for
1576 * changing frequency are suspended quickly after this point.
1578 void cpufreq_suspend(void)
1580 struct cpufreq_policy *policy;
1582 if (!cpufreq_driver)
1588 pr_debug("%s: Suspending Governors\n", __func__);
1590 for_each_active_policy(policy) {
1591 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1592 pr_err("%s: Failed to stop governor for policy: %p\n",
1594 else if (cpufreq_driver->suspend
1595 && cpufreq_driver->suspend(policy))
1596 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1601 cpufreq_suspended = true;
1605 * cpufreq_resume() - Resume CPUFreq governors
1607 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1608 * are suspended with cpufreq_suspend().
1610 void cpufreq_resume(void)
1612 struct cpufreq_policy *policy;
1614 if (!cpufreq_driver)
1617 cpufreq_suspended = false;
1622 pr_debug("%s: Resuming Governors\n", __func__);
1624 for_each_active_policy(policy) {
1625 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1626 pr_err("%s: Failed to resume driver: %p\n", __func__,
1628 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1629 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1630 pr_err("%s: Failed to start governor for policy: %p\n",
1635 * schedule call cpufreq_update_policy() for first-online CPU, as that
1636 * wouldn't be hotplugged-out on suspend. It will verify that the
1637 * current freq is in sync with what we believe it to be.
1639 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1640 if (WARN_ON(!policy))
1643 schedule_work(&policy->update);
1647 * cpufreq_get_current_driver - return current driver's name
1649 * Return the name string of the currently loaded cpufreq driver
1652 const char *cpufreq_get_current_driver(void)
1655 return cpufreq_driver->name;
1659 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1662 * cpufreq_get_driver_data - return current driver data
1664 * Return the private data of the currently loaded cpufreq
1665 * driver, or NULL if no cpufreq driver is loaded.
1667 void *cpufreq_get_driver_data(void)
1670 return cpufreq_driver->driver_data;
1674 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1676 /*********************************************************************
1677 * NOTIFIER LISTS INTERFACE *
1678 *********************************************************************/
1681 * cpufreq_register_notifier - register a driver with cpufreq
1682 * @nb: notifier function to register
1683 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1685 * Add a driver to one of two lists: either a list of drivers that
1686 * are notified about clock rate changes (once before and once after
1687 * the transition), or a list of drivers that are notified about
1688 * changes in cpufreq policy.
1690 * This function may sleep, and has the same return conditions as
1691 * blocking_notifier_chain_register.
1693 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1697 if (cpufreq_disabled())
1700 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1703 case CPUFREQ_TRANSITION_NOTIFIER:
1704 ret = srcu_notifier_chain_register(
1705 &cpufreq_transition_notifier_list, nb);
1707 case CPUFREQ_POLICY_NOTIFIER:
1708 ret = blocking_notifier_chain_register(
1709 &cpufreq_policy_notifier_list, nb);
1717 EXPORT_SYMBOL(cpufreq_register_notifier);
1720 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1721 * @nb: notifier block to be unregistered
1722 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1724 * Remove a driver from the CPU frequency notifier list.
1726 * This function may sleep, and has the same return conditions as
1727 * blocking_notifier_chain_unregister.
1729 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1733 if (cpufreq_disabled())
1737 case CPUFREQ_TRANSITION_NOTIFIER:
1738 ret = srcu_notifier_chain_unregister(
1739 &cpufreq_transition_notifier_list, nb);
1741 case CPUFREQ_POLICY_NOTIFIER:
1742 ret = blocking_notifier_chain_unregister(
1743 &cpufreq_policy_notifier_list, nb);
1751 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1754 /*********************************************************************
1756 *********************************************************************/
1758 /* Must set freqs->new to intermediate frequency */
1759 static int __target_intermediate(struct cpufreq_policy *policy,
1760 struct cpufreq_freqs *freqs, int index)
1764 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1766 /* We don't need to switch to intermediate freq */
1770 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1771 __func__, policy->cpu, freqs->old, freqs->new);
1773 cpufreq_freq_transition_begin(policy, freqs);
1774 ret = cpufreq_driver->target_intermediate(policy, index);
1775 cpufreq_freq_transition_end(policy, freqs, ret);
1778 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1784 static int __target_index(struct cpufreq_policy *policy,
1785 struct cpufreq_frequency_table *freq_table, int index)
1787 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1788 unsigned int intermediate_freq = 0;
1789 int retval = -EINVAL;
1792 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1794 /* Handle switching to intermediate frequency */
1795 if (cpufreq_driver->get_intermediate) {
1796 retval = __target_intermediate(policy, &freqs, index);
1800 intermediate_freq = freqs.new;
1801 /* Set old freq to intermediate */
1802 if (intermediate_freq)
1803 freqs.old = freqs.new;
1806 freqs.new = freq_table[index].frequency;
1807 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1808 __func__, policy->cpu, freqs.old, freqs.new);
1810 cpufreq_freq_transition_begin(policy, &freqs);
1813 retval = cpufreq_driver->target_index(policy, index);
1815 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1819 cpufreq_freq_transition_end(policy, &freqs, retval);
1822 * Failed after setting to intermediate freq? Driver should have
1823 * reverted back to initial frequency and so should we. Check
1824 * here for intermediate_freq instead of get_intermediate, in
1825 * case we haven't switched to intermediate freq at all.
1827 if (unlikely(retval && intermediate_freq)) {
1828 freqs.old = intermediate_freq;
1829 freqs.new = policy->restore_freq;
1830 cpufreq_freq_transition_begin(policy, &freqs);
1831 cpufreq_freq_transition_end(policy, &freqs, 0);
1838 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1839 unsigned int target_freq,
1840 unsigned int relation)
1842 unsigned int old_target_freq = target_freq;
1843 int retval = -EINVAL;
1845 if (cpufreq_disabled())
1848 /* Make sure that target_freq is within supported range */
1849 if (target_freq > policy->max)
1850 target_freq = policy->max;
1851 if (target_freq < policy->min)
1852 target_freq = policy->min;
1854 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1855 policy->cpu, target_freq, relation, old_target_freq);
1858 * This might look like a redundant call as we are checking it again
1859 * after finding index. But it is left intentionally for cases where
1860 * exactly same freq is called again and so we can save on few function
1863 if (target_freq == policy->cur)
1866 /* Save last value to restore later on errors */
1867 policy->restore_freq = policy->cur;
1869 if (cpufreq_driver->target)
1870 retval = cpufreq_driver->target(policy, target_freq, relation);
1871 else if (cpufreq_driver->target_index) {
1872 struct cpufreq_frequency_table *freq_table;
1875 freq_table = cpufreq_frequency_get_table(policy->cpu);
1876 if (unlikely(!freq_table)) {
1877 pr_err("%s: Unable to find freq_table\n", __func__);
1881 retval = cpufreq_frequency_table_target(policy, freq_table,
1882 target_freq, relation, &index);
1883 if (unlikely(retval)) {
1884 pr_err("%s: Unable to find matching freq\n", __func__);
1888 if (freq_table[index].frequency == policy->cur) {
1893 retval = __target_index(policy, freq_table, index);
1899 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1901 int cpufreq_driver_target(struct cpufreq_policy *policy,
1902 unsigned int target_freq,
1903 unsigned int relation)
1907 down_write(&policy->rwsem);
1909 ret = __cpufreq_driver_target(policy, target_freq, relation);
1911 up_write(&policy->rwsem);
1915 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1917 static int __cpufreq_governor(struct cpufreq_policy *policy,
1922 /* Only must be defined when default governor is known to have latency
1923 restrictions, like e.g. conservative or ondemand.
1924 That this is the case is already ensured in Kconfig
1926 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1927 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1929 struct cpufreq_governor *gov = NULL;
1932 /* Don't start any governor operations if we are entering suspend */
1933 if (cpufreq_suspended)
1936 * Governor might not be initiated here if ACPI _PPC changed
1937 * notification happened, so check it.
1939 if (!policy->governor)
1942 if (policy->governor->max_transition_latency &&
1943 policy->cpuinfo.transition_latency >
1944 policy->governor->max_transition_latency) {
1948 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1949 policy->governor->name, gov->name);
1950 policy->governor = gov;
1954 if (event == CPUFREQ_GOV_POLICY_INIT)
1955 if (!try_module_get(policy->governor->owner))
1958 pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
1960 mutex_lock(&cpufreq_governor_lock);
1961 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1962 || (!policy->governor_enabled
1963 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1964 mutex_unlock(&cpufreq_governor_lock);
1968 if (event == CPUFREQ_GOV_STOP)
1969 policy->governor_enabled = false;
1970 else if (event == CPUFREQ_GOV_START)
1971 policy->governor_enabled = true;
1973 mutex_unlock(&cpufreq_governor_lock);
1975 ret = policy->governor->governor(policy, event);
1978 if (event == CPUFREQ_GOV_POLICY_INIT)
1979 policy->governor->initialized++;
1980 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1981 policy->governor->initialized--;
1983 /* Restore original values */
1984 mutex_lock(&cpufreq_governor_lock);
1985 if (event == CPUFREQ_GOV_STOP)
1986 policy->governor_enabled = true;
1987 else if (event == CPUFREQ_GOV_START)
1988 policy->governor_enabled = false;
1989 mutex_unlock(&cpufreq_governor_lock);
1992 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
1993 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
1994 module_put(policy->governor->owner);
1999 int cpufreq_register_governor(struct cpufreq_governor *governor)
2006 if (cpufreq_disabled())
2009 mutex_lock(&cpufreq_governor_mutex);
2011 governor->initialized = 0;
2013 if (!find_governor(governor->name)) {
2015 list_add(&governor->governor_list, &cpufreq_governor_list);
2018 mutex_unlock(&cpufreq_governor_mutex);
2021 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2023 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2025 struct cpufreq_policy *policy;
2026 unsigned long flags;
2031 if (cpufreq_disabled())
2034 /* clear last_governor for all inactive policies */
2035 read_lock_irqsave(&cpufreq_driver_lock, flags);
2036 for_each_inactive_policy(policy) {
2037 if (!strcmp(policy->last_governor, governor->name)) {
2038 policy->governor = NULL;
2039 strcpy(policy->last_governor, "\0");
2042 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2044 mutex_lock(&cpufreq_governor_mutex);
2045 list_del(&governor->governor_list);
2046 mutex_unlock(&cpufreq_governor_mutex);
2049 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2052 /*********************************************************************
2053 * POLICY INTERFACE *
2054 *********************************************************************/
2057 * cpufreq_get_policy - get the current cpufreq_policy
2058 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2061 * Reads the current cpufreq policy.
2063 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2065 struct cpufreq_policy *cpu_policy;
2069 cpu_policy = cpufreq_cpu_get(cpu);
2073 memcpy(policy, cpu_policy, sizeof(*policy));
2075 cpufreq_cpu_put(cpu_policy);
2078 EXPORT_SYMBOL(cpufreq_get_policy);
2081 * policy : current policy.
2082 * new_policy: policy to be set.
2084 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2085 struct cpufreq_policy *new_policy)
2087 struct cpufreq_governor *old_gov;
2090 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2091 new_policy->cpu, new_policy->min, new_policy->max);
2093 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2096 * This check works well when we store new min/max freq attributes,
2097 * because new_policy is a copy of policy with one field updated.
2099 if (new_policy->min > new_policy->max)
2102 /* verify the cpu speed can be set within this limit */
2103 ret = cpufreq_driver->verify(new_policy);
2107 /* adjust if necessary - all reasons */
2108 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2109 CPUFREQ_ADJUST, new_policy);
2112 * verify the cpu speed can be set within this limit, which might be
2113 * different to the first one
2115 ret = cpufreq_driver->verify(new_policy);
2119 /* notification of the new policy */
2120 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2121 CPUFREQ_NOTIFY, new_policy);
2123 policy->min = new_policy->min;
2124 policy->max = new_policy->max;
2126 pr_debug("new min and max freqs are %u - %u kHz\n",
2127 policy->min, policy->max);
2129 if (cpufreq_driver->setpolicy) {
2130 policy->policy = new_policy->policy;
2131 pr_debug("setting range\n");
2132 return cpufreq_driver->setpolicy(new_policy);
2135 if (new_policy->governor == policy->governor)
2138 pr_debug("governor switch\n");
2140 /* save old, working values */
2141 old_gov = policy->governor;
2142 /* end old governor */
2144 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2146 /* This can happen due to race with other operations */
2147 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2148 __func__, old_gov->name, ret);
2152 up_write(&policy->rwsem);
2153 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2154 down_write(&policy->rwsem);
2157 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2158 __func__, old_gov->name, ret);
2163 /* start new governor */
2164 policy->governor = new_policy->governor;
2165 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2167 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2171 up_write(&policy->rwsem);
2172 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2173 down_write(&policy->rwsem);
2176 /* new governor failed, so re-start old one */
2177 pr_debug("starting governor %s failed\n", policy->governor->name);
2179 policy->governor = old_gov;
2180 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2181 policy->governor = NULL;
2183 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2189 pr_debug("governor: change or update limits\n");
2190 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2194 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2195 * @cpu: CPU which shall be re-evaluated
2197 * Useful for policy notifiers which have different necessities
2198 * at different times.
2200 int cpufreq_update_policy(unsigned int cpu)
2202 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2203 struct cpufreq_policy new_policy;
2209 down_write(&policy->rwsem);
2211 pr_debug("updating policy for CPU %u\n", cpu);
2212 memcpy(&new_policy, policy, sizeof(*policy));
2213 new_policy.min = policy->user_policy.min;
2214 new_policy.max = policy->user_policy.max;
2217 * BIOS might change freq behind our back
2218 * -> ask driver for current freq and notify governors about a change
2220 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2221 new_policy.cur = cpufreq_driver->get(cpu);
2222 if (WARN_ON(!new_policy.cur)) {
2228 pr_debug("Driver did not initialize current freq\n");
2229 policy->cur = new_policy.cur;
2231 if (policy->cur != new_policy.cur && has_target())
2232 cpufreq_out_of_sync(policy, new_policy.cur);
2236 ret = cpufreq_set_policy(policy, &new_policy);
2239 up_write(&policy->rwsem);
2241 cpufreq_cpu_put(policy);
2244 EXPORT_SYMBOL(cpufreq_update_policy);
2246 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2247 unsigned long action, void *hcpu)
2249 unsigned int cpu = (unsigned long)hcpu;
2251 switch (action & ~CPU_TASKS_FROZEN) {
2253 cpufreq_online(cpu);
2256 case CPU_DOWN_PREPARE:
2257 cpufreq_offline_prepare(cpu);
2261 cpufreq_offline_finish(cpu);
2264 case CPU_DOWN_FAILED:
2265 cpufreq_online(cpu);
2271 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2272 .notifier_call = cpufreq_cpu_callback,
2275 /*********************************************************************
2277 *********************************************************************/
2278 static int cpufreq_boost_set_sw(int state)
2280 struct cpufreq_frequency_table *freq_table;
2281 struct cpufreq_policy *policy;
2284 for_each_active_policy(policy) {
2285 freq_table = cpufreq_frequency_get_table(policy->cpu);
2287 ret = cpufreq_frequency_table_cpuinfo(policy,
2290 pr_err("%s: Policy frequency update failed\n",
2294 policy->user_policy.max = policy->max;
2295 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2302 int cpufreq_boost_trigger_state(int state)
2304 unsigned long flags;
2307 if (cpufreq_driver->boost_enabled == state)
2310 write_lock_irqsave(&cpufreq_driver_lock, flags);
2311 cpufreq_driver->boost_enabled = state;
2312 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2314 ret = cpufreq_driver->set_boost(state);
2316 write_lock_irqsave(&cpufreq_driver_lock, flags);
2317 cpufreq_driver->boost_enabled = !state;
2318 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2320 pr_err("%s: Cannot %s BOOST\n",
2321 __func__, state ? "enable" : "disable");
2327 int cpufreq_boost_supported(void)
2329 if (likely(cpufreq_driver))
2330 return cpufreq_driver->boost_supported;
2334 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2336 static int create_boost_sysfs_file(void)
2340 if (!cpufreq_boost_supported())
2344 * Check if driver provides function to enable boost -
2345 * if not, use cpufreq_boost_set_sw as default
2347 if (!cpufreq_driver->set_boost)
2348 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2350 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2352 pr_err("%s: cannot register global BOOST sysfs file\n",
2358 static void remove_boost_sysfs_file(void)
2360 if (cpufreq_boost_supported())
2361 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2364 int cpufreq_enable_boost_support(void)
2366 if (!cpufreq_driver)
2369 if (cpufreq_boost_supported())
2372 cpufreq_driver->boost_supported = true;
2374 /* This will get removed on driver unregister */
2375 return create_boost_sysfs_file();
2377 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2379 int cpufreq_boost_enabled(void)
2381 return cpufreq_driver->boost_enabled;
2383 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2385 /*********************************************************************
2386 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2387 *********************************************************************/
2390 * cpufreq_register_driver - register a CPU Frequency driver
2391 * @driver_data: A struct cpufreq_driver containing the values#
2392 * submitted by the CPU Frequency driver.
2394 * Registers a CPU Frequency driver to this core code. This code
2395 * returns zero on success, -EBUSY when another driver got here first
2396 * (and isn't unregistered in the meantime).
2399 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2401 unsigned long flags;
2404 if (cpufreq_disabled())
2407 if (!driver_data || !driver_data->verify || !driver_data->init ||
2408 !(driver_data->setpolicy || driver_data->target_index ||
2409 driver_data->target) ||
2410 (driver_data->setpolicy && (driver_data->target_index ||
2411 driver_data->target)) ||
2412 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2415 pr_debug("trying to register driver %s\n", driver_data->name);
2417 /* Protect against concurrent CPU online/offline. */
2420 write_lock_irqsave(&cpufreq_driver_lock, flags);
2421 if (cpufreq_driver) {
2422 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2426 cpufreq_driver = driver_data;
2427 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2429 if (driver_data->setpolicy)
2430 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2432 ret = create_boost_sysfs_file();
2434 goto err_null_driver;
2436 ret = subsys_interface_register(&cpufreq_interface);
2438 goto err_boost_unreg;
2440 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2441 list_empty(&cpufreq_policy_list)) {
2442 /* if all ->init() calls failed, unregister */
2443 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2448 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2449 pr_debug("driver %s up and running\n", driver_data->name);
2456 subsys_interface_unregister(&cpufreq_interface);
2458 remove_boost_sysfs_file();
2460 write_lock_irqsave(&cpufreq_driver_lock, flags);
2461 cpufreq_driver = NULL;
2462 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2465 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2468 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2470 * Unregister the current CPUFreq driver. Only call this if you have
2471 * the right to do so, i.e. if you have succeeded in initialising before!
2472 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2473 * currently not initialised.
2475 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2477 unsigned long flags;
2479 if (!cpufreq_driver || (driver != cpufreq_driver))
2482 pr_debug("unregistering driver %s\n", driver->name);
2484 /* Protect against concurrent cpu hotplug */
2486 subsys_interface_unregister(&cpufreq_interface);
2487 remove_boost_sysfs_file();
2488 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2490 write_lock_irqsave(&cpufreq_driver_lock, flags);
2492 cpufreq_driver = NULL;
2494 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2499 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2502 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2503 * or mutexes when secondary CPUs are halted.
2505 static struct syscore_ops cpufreq_syscore_ops = {
2506 .shutdown = cpufreq_suspend,
2509 struct kobject *cpufreq_global_kobject;
2510 EXPORT_SYMBOL(cpufreq_global_kobject);
2512 static int __init cpufreq_core_init(void)
2514 if (cpufreq_disabled())
2517 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2518 BUG_ON(!cpufreq_global_kobject);
2520 register_syscore_ops(&cpufreq_syscore_ops);
2524 core_initcall(cpufreq_core_init);