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 /* No more policies in the list */
52 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
55 policy = list_next_entry(policy, 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 __weak struct cpufreq_governor *cpufreq_default_governor(void)
967 static int cpufreq_init_policy(struct cpufreq_policy *policy)
969 struct cpufreq_governor *gov = NULL;
970 struct cpufreq_policy new_policy;
972 memcpy(&new_policy, policy, sizeof(*policy));
974 /* Update governor of new_policy to the governor used before hotplug */
975 gov = find_governor(policy->last_governor);
977 pr_debug("Restoring governor %s for cpu %d\n",
978 policy->governor->name, policy->cpu);
980 gov = cpufreq_default_governor();
985 new_policy.governor = gov;
987 /* Use the default policy if there is no last_policy. */
988 if (cpufreq_driver->setpolicy) {
989 if (policy->last_policy)
990 new_policy.policy = policy->last_policy;
992 cpufreq_parse_governor(gov->name, &new_policy.policy,
995 /* set default policy */
996 return cpufreq_set_policy(policy, &new_policy);
999 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1003 /* Has this CPU been taken care of already? */
1004 if (cpumask_test_cpu(cpu, policy->cpus))
1008 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1010 pr_err("%s: Failed to stop governor\n", __func__);
1015 down_write(&policy->rwsem);
1016 cpumask_set_cpu(cpu, policy->cpus);
1017 up_write(&policy->rwsem);
1020 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1022 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1025 pr_err("%s: Failed to start governor\n", __func__);
1033 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1035 struct device *dev = get_cpu_device(cpu);
1036 struct cpufreq_policy *policy;
1041 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1045 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1046 goto err_free_policy;
1048 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1049 goto err_free_cpumask;
1051 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1052 goto err_free_rcpumask;
1054 kobject_init(&policy->kobj, &ktype_cpufreq);
1055 INIT_LIST_HEAD(&policy->policy_list);
1056 init_rwsem(&policy->rwsem);
1057 spin_lock_init(&policy->transition_lock);
1058 init_waitqueue_head(&policy->transition_wait);
1059 init_completion(&policy->kobj_unregister);
1060 INIT_WORK(&policy->update, handle_update);
1066 free_cpumask_var(policy->related_cpus);
1068 free_cpumask_var(policy->cpus);
1075 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1077 struct kobject *kobj;
1078 struct completion *cmp;
1081 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1082 CPUFREQ_REMOVE_POLICY, policy);
1084 down_write(&policy->rwsem);
1085 cpufreq_remove_dev_symlink(policy);
1086 kobj = &policy->kobj;
1087 cmp = &policy->kobj_unregister;
1088 up_write(&policy->rwsem);
1092 * We need to make sure that the underlying kobj is
1093 * actually not referenced anymore by anybody before we
1094 * proceed with unloading.
1096 pr_debug("waiting for dropping of refcount\n");
1097 wait_for_completion(cmp);
1098 pr_debug("wait complete\n");
1101 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1103 unsigned long flags;
1106 /* Remove policy from list */
1107 write_lock_irqsave(&cpufreq_driver_lock, flags);
1108 list_del(&policy->policy_list);
1110 for_each_cpu(cpu, policy->related_cpus)
1111 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1112 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1114 cpufreq_policy_put_kobj(policy, notify);
1115 free_cpumask_var(policy->real_cpus);
1116 free_cpumask_var(policy->related_cpus);
1117 free_cpumask_var(policy->cpus);
1121 static int cpufreq_online(unsigned int cpu)
1123 struct cpufreq_policy *policy;
1125 unsigned long flags;
1129 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1131 /* Check if this CPU already has a policy to manage it */
1132 policy = per_cpu(cpufreq_cpu_data, cpu);
1134 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1135 if (!policy_is_inactive(policy))
1136 return cpufreq_add_policy_cpu(policy, cpu);
1138 /* This is the only online CPU for the policy. Start over. */
1140 down_write(&policy->rwsem);
1142 policy->governor = NULL;
1143 up_write(&policy->rwsem);
1146 policy = cpufreq_policy_alloc(cpu);
1151 cpumask_copy(policy->cpus, cpumask_of(cpu));
1153 /* call driver. From then on the cpufreq must be able
1154 * to accept all calls to ->verify and ->setpolicy for this CPU
1156 ret = cpufreq_driver->init(policy);
1158 pr_debug("initialization failed\n");
1159 goto out_free_policy;
1162 down_write(&policy->rwsem);
1165 /* related_cpus should at least include policy->cpus. */
1166 cpumask_copy(policy->related_cpus, policy->cpus);
1167 /* Remember CPUs present at the policy creation time. */
1168 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1170 /* Name and add the kobject */
1171 ret = kobject_add(&policy->kobj, cpufreq_global_kobject,
1173 cpumask_first(policy->related_cpus));
1175 pr_err("%s: failed to add policy->kobj: %d\n", __func__,
1177 goto out_exit_policy;
1182 * affected cpus must always be the one, which are online. We aren't
1183 * managing offline cpus here.
1185 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1188 policy->user_policy.min = policy->min;
1189 policy->user_policy.max = policy->max;
1191 write_lock_irqsave(&cpufreq_driver_lock, flags);
1192 for_each_cpu(j, policy->related_cpus)
1193 per_cpu(cpufreq_cpu_data, j) = policy;
1194 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1197 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1198 policy->cur = cpufreq_driver->get(policy->cpu);
1200 pr_err("%s: ->get() failed\n", __func__);
1201 goto out_exit_policy;
1206 * Sometimes boot loaders set CPU frequency to a value outside of
1207 * frequency table present with cpufreq core. In such cases CPU might be
1208 * unstable if it has to run on that frequency for long duration of time
1209 * and so its better to set it to a frequency which is specified in
1210 * freq-table. This also makes cpufreq stats inconsistent as
1211 * cpufreq-stats would fail to register because current frequency of CPU
1212 * isn't found in freq-table.
1214 * Because we don't want this change to effect boot process badly, we go
1215 * for the next freq which is >= policy->cur ('cur' must be set by now,
1216 * otherwise we will end up setting freq to lowest of the table as 'cur'
1217 * is initialized to zero).
1219 * We are passing target-freq as "policy->cur - 1" otherwise
1220 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1221 * equal to target-freq.
1223 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1225 /* Are we running at unknown frequency ? */
1226 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1227 if (ret == -EINVAL) {
1228 /* Warn user and fix it */
1229 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1230 __func__, policy->cpu, policy->cur);
1231 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1232 CPUFREQ_RELATION_L);
1235 * Reaching here after boot in a few seconds may not
1236 * mean that system will remain stable at "unknown"
1237 * frequency for longer duration. Hence, a BUG_ON().
1240 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1241 __func__, policy->cpu, policy->cur);
1245 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1246 CPUFREQ_START, policy);
1249 ret = cpufreq_add_dev_interface(policy);
1251 goto out_exit_policy;
1252 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1253 CPUFREQ_CREATE_POLICY, policy);
1255 write_lock_irqsave(&cpufreq_driver_lock, flags);
1256 list_add(&policy->policy_list, &cpufreq_policy_list);
1257 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1260 ret = cpufreq_init_policy(policy);
1262 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1263 __func__, cpu, ret);
1264 /* cpufreq_policy_free() will notify based on this */
1266 goto out_exit_policy;
1269 up_write(&policy->rwsem);
1271 kobject_uevent(&policy->kobj, KOBJ_ADD);
1273 /* Callback for handling stuff after policy is ready */
1274 if (cpufreq_driver->ready)
1275 cpufreq_driver->ready(policy);
1277 pr_debug("initialization complete\n");
1282 up_write(&policy->rwsem);
1284 if (cpufreq_driver->exit)
1285 cpufreq_driver->exit(policy);
1287 cpufreq_policy_free(policy, !new_policy);
1292 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1294 * @sif: Subsystem interface structure pointer (not used)
1296 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1298 unsigned cpu = dev->id;
1301 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1303 if (cpu_online(cpu)) {
1304 ret = cpufreq_online(cpu);
1307 * A hotplug notifier will follow and we will handle it as CPU
1308 * online then. For now, just create the sysfs link, unless
1309 * there is no policy or the link is already present.
1311 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1313 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1314 ? add_cpu_dev_symlink(policy, cpu) : 0;
1320 static void cpufreq_offline_prepare(unsigned int cpu)
1322 struct cpufreq_policy *policy;
1324 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1326 policy = cpufreq_cpu_get_raw(cpu);
1328 pr_debug("%s: No cpu_data found\n", __func__);
1333 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1335 pr_err("%s: Failed to stop governor\n", __func__);
1338 down_write(&policy->rwsem);
1339 cpumask_clear_cpu(cpu, policy->cpus);
1341 if (policy_is_inactive(policy)) {
1343 strncpy(policy->last_governor, policy->governor->name,
1346 policy->last_policy = policy->policy;
1347 } else if (cpu == policy->cpu) {
1348 /* Nominate new CPU */
1349 policy->cpu = cpumask_any(policy->cpus);
1351 up_write(&policy->rwsem);
1353 /* Start governor again for active policy */
1354 if (!policy_is_inactive(policy)) {
1356 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1358 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1361 pr_err("%s: Failed to start governor\n", __func__);
1363 } else if (cpufreq_driver->stop_cpu) {
1364 cpufreq_driver->stop_cpu(policy);
1368 static void cpufreq_offline_finish(unsigned int cpu)
1370 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1373 pr_debug("%s: No cpu_data found\n", __func__);
1377 /* Only proceed for inactive policies */
1378 if (!policy_is_inactive(policy))
1381 /* If cpu is last user of policy, free policy */
1383 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1385 pr_err("%s: Failed to exit governor\n", __func__);
1389 * Perform the ->exit() even during light-weight tear-down,
1390 * since this is a core component, and is essential for the
1391 * subsequent light-weight ->init() to succeed.
1393 if (cpufreq_driver->exit) {
1394 cpufreq_driver->exit(policy);
1395 policy->freq_table = NULL;
1400 * cpufreq_remove_dev - remove a CPU device
1402 * Removes the cpufreq interface for a CPU device.
1404 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1406 unsigned int cpu = dev->id;
1407 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1412 if (cpu_online(cpu)) {
1413 cpufreq_offline_prepare(cpu);
1414 cpufreq_offline_finish(cpu);
1417 cpumask_clear_cpu(cpu, policy->real_cpus);
1418 remove_cpu_dev_symlink(policy, cpu);
1420 if (cpumask_empty(policy->real_cpus))
1421 cpufreq_policy_free(policy, true);
1424 static void handle_update(struct work_struct *work)
1426 struct cpufreq_policy *policy =
1427 container_of(work, struct cpufreq_policy, update);
1428 unsigned int cpu = policy->cpu;
1429 pr_debug("handle_update for cpu %u called\n", cpu);
1430 cpufreq_update_policy(cpu);
1434 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1436 * @policy: policy managing CPUs
1437 * @new_freq: CPU frequency the CPU actually runs at
1439 * We adjust to current frequency first, and need to clean up later.
1440 * So either call to cpufreq_update_policy() or schedule handle_update()).
1442 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1443 unsigned int new_freq)
1445 struct cpufreq_freqs freqs;
1447 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1448 policy->cur, new_freq);
1450 freqs.old = policy->cur;
1451 freqs.new = new_freq;
1453 cpufreq_freq_transition_begin(policy, &freqs);
1454 cpufreq_freq_transition_end(policy, &freqs, 0);
1458 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1461 * This is the last known freq, without actually getting it from the driver.
1462 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1464 unsigned int cpufreq_quick_get(unsigned int cpu)
1466 struct cpufreq_policy *policy;
1467 unsigned int ret_freq = 0;
1469 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1470 return cpufreq_driver->get(cpu);
1472 policy = cpufreq_cpu_get(cpu);
1474 ret_freq = policy->cur;
1475 cpufreq_cpu_put(policy);
1480 EXPORT_SYMBOL(cpufreq_quick_get);
1483 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1486 * Just return the max possible frequency for a given CPU.
1488 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1490 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1491 unsigned int ret_freq = 0;
1494 ret_freq = policy->max;
1495 cpufreq_cpu_put(policy);
1500 EXPORT_SYMBOL(cpufreq_quick_get_max);
1502 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1504 unsigned int ret_freq = 0;
1506 if (!cpufreq_driver->get)
1509 ret_freq = cpufreq_driver->get(policy->cpu);
1511 /* Updating inactive policies is invalid, so avoid doing that. */
1512 if (unlikely(policy_is_inactive(policy)))
1515 if (ret_freq && policy->cur &&
1516 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1517 /* verify no discrepancy between actual and
1518 saved value exists */
1519 if (unlikely(ret_freq != policy->cur)) {
1520 cpufreq_out_of_sync(policy, ret_freq);
1521 schedule_work(&policy->update);
1529 * cpufreq_get - get the current CPU frequency (in kHz)
1532 * Get the CPU current (static) CPU frequency
1534 unsigned int cpufreq_get(unsigned int cpu)
1536 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1537 unsigned int ret_freq = 0;
1540 down_read(&policy->rwsem);
1541 ret_freq = __cpufreq_get(policy);
1542 up_read(&policy->rwsem);
1544 cpufreq_cpu_put(policy);
1549 EXPORT_SYMBOL(cpufreq_get);
1551 static struct subsys_interface cpufreq_interface = {
1553 .subsys = &cpu_subsys,
1554 .add_dev = cpufreq_add_dev,
1555 .remove_dev = cpufreq_remove_dev,
1559 * In case platform wants some specific frequency to be configured
1562 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1566 if (!policy->suspend_freq) {
1567 pr_debug("%s: suspend_freq not defined\n", __func__);
1571 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1572 policy->suspend_freq);
1574 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1575 CPUFREQ_RELATION_H);
1577 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1578 __func__, policy->suspend_freq, ret);
1582 EXPORT_SYMBOL(cpufreq_generic_suspend);
1585 * cpufreq_suspend() - Suspend CPUFreq governors
1587 * Called during system wide Suspend/Hibernate cycles for suspending governors
1588 * as some platforms can't change frequency after this point in suspend cycle.
1589 * Because some of the devices (like: i2c, regulators, etc) they use for
1590 * changing frequency are suspended quickly after this point.
1592 void cpufreq_suspend(void)
1594 struct cpufreq_policy *policy;
1596 if (!cpufreq_driver)
1602 pr_debug("%s: Suspending Governors\n", __func__);
1604 for_each_active_policy(policy) {
1605 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1606 pr_err("%s: Failed to stop governor for policy: %p\n",
1608 else if (cpufreq_driver->suspend
1609 && cpufreq_driver->suspend(policy))
1610 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1615 cpufreq_suspended = true;
1619 * cpufreq_resume() - Resume CPUFreq governors
1621 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1622 * are suspended with cpufreq_suspend().
1624 void cpufreq_resume(void)
1626 struct cpufreq_policy *policy;
1628 if (!cpufreq_driver)
1631 cpufreq_suspended = false;
1636 pr_debug("%s: Resuming Governors\n", __func__);
1638 for_each_active_policy(policy) {
1639 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1640 pr_err("%s: Failed to resume driver: %p\n", __func__,
1642 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1643 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1644 pr_err("%s: Failed to start governor for policy: %p\n",
1649 * schedule call cpufreq_update_policy() for first-online CPU, as that
1650 * wouldn't be hotplugged-out on suspend. It will verify that the
1651 * current freq is in sync with what we believe it to be.
1653 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1654 if (WARN_ON(!policy))
1657 schedule_work(&policy->update);
1661 * cpufreq_get_current_driver - return current driver's name
1663 * Return the name string of the currently loaded cpufreq driver
1666 const char *cpufreq_get_current_driver(void)
1669 return cpufreq_driver->name;
1673 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1676 * cpufreq_get_driver_data - return current driver data
1678 * Return the private data of the currently loaded cpufreq
1679 * driver, or NULL if no cpufreq driver is loaded.
1681 void *cpufreq_get_driver_data(void)
1684 return cpufreq_driver->driver_data;
1688 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1690 /*********************************************************************
1691 * NOTIFIER LISTS INTERFACE *
1692 *********************************************************************/
1695 * cpufreq_register_notifier - register a driver with cpufreq
1696 * @nb: notifier function to register
1697 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1699 * Add a driver to one of two lists: either a list of drivers that
1700 * are notified about clock rate changes (once before and once after
1701 * the transition), or a list of drivers that are notified about
1702 * changes in cpufreq policy.
1704 * This function may sleep, and has the same return conditions as
1705 * blocking_notifier_chain_register.
1707 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1711 if (cpufreq_disabled())
1714 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1717 case CPUFREQ_TRANSITION_NOTIFIER:
1718 ret = srcu_notifier_chain_register(
1719 &cpufreq_transition_notifier_list, nb);
1721 case CPUFREQ_POLICY_NOTIFIER:
1722 ret = blocking_notifier_chain_register(
1723 &cpufreq_policy_notifier_list, nb);
1731 EXPORT_SYMBOL(cpufreq_register_notifier);
1734 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1735 * @nb: notifier block to be unregistered
1736 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1738 * Remove a driver from the CPU frequency notifier list.
1740 * This function may sleep, and has the same return conditions as
1741 * blocking_notifier_chain_unregister.
1743 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1747 if (cpufreq_disabled())
1751 case CPUFREQ_TRANSITION_NOTIFIER:
1752 ret = srcu_notifier_chain_unregister(
1753 &cpufreq_transition_notifier_list, nb);
1755 case CPUFREQ_POLICY_NOTIFIER:
1756 ret = blocking_notifier_chain_unregister(
1757 &cpufreq_policy_notifier_list, nb);
1765 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1768 /*********************************************************************
1770 *********************************************************************/
1772 /* Must set freqs->new to intermediate frequency */
1773 static int __target_intermediate(struct cpufreq_policy *policy,
1774 struct cpufreq_freqs *freqs, int index)
1778 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1780 /* We don't need to switch to intermediate freq */
1784 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1785 __func__, policy->cpu, freqs->old, freqs->new);
1787 cpufreq_freq_transition_begin(policy, freqs);
1788 ret = cpufreq_driver->target_intermediate(policy, index);
1789 cpufreq_freq_transition_end(policy, freqs, ret);
1792 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1798 static int __target_index(struct cpufreq_policy *policy,
1799 struct cpufreq_frequency_table *freq_table, int index)
1801 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1802 unsigned int intermediate_freq = 0;
1803 int retval = -EINVAL;
1806 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1808 /* Handle switching to intermediate frequency */
1809 if (cpufreq_driver->get_intermediate) {
1810 retval = __target_intermediate(policy, &freqs, index);
1814 intermediate_freq = freqs.new;
1815 /* Set old freq to intermediate */
1816 if (intermediate_freq)
1817 freqs.old = freqs.new;
1820 freqs.new = freq_table[index].frequency;
1821 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1822 __func__, policy->cpu, freqs.old, freqs.new);
1824 cpufreq_freq_transition_begin(policy, &freqs);
1827 retval = cpufreq_driver->target_index(policy, index);
1829 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1833 cpufreq_freq_transition_end(policy, &freqs, retval);
1836 * Failed after setting to intermediate freq? Driver should have
1837 * reverted back to initial frequency and so should we. Check
1838 * here for intermediate_freq instead of get_intermediate, in
1839 * case we haven't switched to intermediate freq at all.
1841 if (unlikely(retval && intermediate_freq)) {
1842 freqs.old = intermediate_freq;
1843 freqs.new = policy->restore_freq;
1844 cpufreq_freq_transition_begin(policy, &freqs);
1845 cpufreq_freq_transition_end(policy, &freqs, 0);
1852 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1853 unsigned int target_freq,
1854 unsigned int relation)
1856 unsigned int old_target_freq = target_freq;
1857 int retval = -EINVAL;
1859 if (cpufreq_disabled())
1862 /* Make sure that target_freq is within supported range */
1863 if (target_freq > policy->max)
1864 target_freq = policy->max;
1865 if (target_freq < policy->min)
1866 target_freq = policy->min;
1868 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1869 policy->cpu, target_freq, relation, old_target_freq);
1872 * This might look like a redundant call as we are checking it again
1873 * after finding index. But it is left intentionally for cases where
1874 * exactly same freq is called again and so we can save on few function
1877 if (target_freq == policy->cur)
1880 /* Save last value to restore later on errors */
1881 policy->restore_freq = policy->cur;
1883 if (cpufreq_driver->target)
1884 retval = cpufreq_driver->target(policy, target_freq, relation);
1885 else if (cpufreq_driver->target_index) {
1886 struct cpufreq_frequency_table *freq_table;
1889 freq_table = cpufreq_frequency_get_table(policy->cpu);
1890 if (unlikely(!freq_table)) {
1891 pr_err("%s: Unable to find freq_table\n", __func__);
1895 retval = cpufreq_frequency_table_target(policy, freq_table,
1896 target_freq, relation, &index);
1897 if (unlikely(retval)) {
1898 pr_err("%s: Unable to find matching freq\n", __func__);
1902 if (freq_table[index].frequency == policy->cur) {
1907 retval = __target_index(policy, freq_table, index);
1913 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1915 int cpufreq_driver_target(struct cpufreq_policy *policy,
1916 unsigned int target_freq,
1917 unsigned int relation)
1921 down_write(&policy->rwsem);
1923 ret = __cpufreq_driver_target(policy, target_freq, relation);
1925 up_write(&policy->rwsem);
1929 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1931 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1936 static int __cpufreq_governor(struct cpufreq_policy *policy,
1941 /* Don't start any governor operations if we are entering suspend */
1942 if (cpufreq_suspended)
1945 * Governor might not be initiated here if ACPI _PPC changed
1946 * notification happened, so check it.
1948 if (!policy->governor)
1951 if (policy->governor->max_transition_latency &&
1952 policy->cpuinfo.transition_latency >
1953 policy->governor->max_transition_latency) {
1954 struct cpufreq_governor *gov = cpufreq_fallback_governor();
1957 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1958 policy->governor->name, gov->name);
1959 policy->governor = gov;
1965 if (event == CPUFREQ_GOV_POLICY_INIT)
1966 if (!try_module_get(policy->governor->owner))
1969 pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
1971 mutex_lock(&cpufreq_governor_lock);
1972 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1973 || (!policy->governor_enabled
1974 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1975 mutex_unlock(&cpufreq_governor_lock);
1979 if (event == CPUFREQ_GOV_STOP)
1980 policy->governor_enabled = false;
1981 else if (event == CPUFREQ_GOV_START)
1982 policy->governor_enabled = true;
1984 mutex_unlock(&cpufreq_governor_lock);
1986 ret = policy->governor->governor(policy, event);
1989 if (event == CPUFREQ_GOV_POLICY_INIT)
1990 policy->governor->initialized++;
1991 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1992 policy->governor->initialized--;
1994 /* Restore original values */
1995 mutex_lock(&cpufreq_governor_lock);
1996 if (event == CPUFREQ_GOV_STOP)
1997 policy->governor_enabled = true;
1998 else if (event == CPUFREQ_GOV_START)
1999 policy->governor_enabled = false;
2000 mutex_unlock(&cpufreq_governor_lock);
2003 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2004 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2005 module_put(policy->governor->owner);
2010 int cpufreq_register_governor(struct cpufreq_governor *governor)
2017 if (cpufreq_disabled())
2020 mutex_lock(&cpufreq_governor_mutex);
2022 governor->initialized = 0;
2024 if (!find_governor(governor->name)) {
2026 list_add(&governor->governor_list, &cpufreq_governor_list);
2029 mutex_unlock(&cpufreq_governor_mutex);
2032 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2034 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2036 struct cpufreq_policy *policy;
2037 unsigned long flags;
2042 if (cpufreq_disabled())
2045 /* clear last_governor for all inactive policies */
2046 read_lock_irqsave(&cpufreq_driver_lock, flags);
2047 for_each_inactive_policy(policy) {
2048 if (!strcmp(policy->last_governor, governor->name)) {
2049 policy->governor = NULL;
2050 strcpy(policy->last_governor, "\0");
2053 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2055 mutex_lock(&cpufreq_governor_mutex);
2056 list_del(&governor->governor_list);
2057 mutex_unlock(&cpufreq_governor_mutex);
2060 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2063 /*********************************************************************
2064 * POLICY INTERFACE *
2065 *********************************************************************/
2068 * cpufreq_get_policy - get the current cpufreq_policy
2069 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2072 * Reads the current cpufreq policy.
2074 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2076 struct cpufreq_policy *cpu_policy;
2080 cpu_policy = cpufreq_cpu_get(cpu);
2084 memcpy(policy, cpu_policy, sizeof(*policy));
2086 cpufreq_cpu_put(cpu_policy);
2089 EXPORT_SYMBOL(cpufreq_get_policy);
2092 * policy : current policy.
2093 * new_policy: policy to be set.
2095 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2096 struct cpufreq_policy *new_policy)
2098 struct cpufreq_governor *old_gov;
2101 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2102 new_policy->cpu, new_policy->min, new_policy->max);
2104 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2107 * This check works well when we store new min/max freq attributes,
2108 * because new_policy is a copy of policy with one field updated.
2110 if (new_policy->min > new_policy->max)
2113 /* verify the cpu speed can be set within this limit */
2114 ret = cpufreq_driver->verify(new_policy);
2118 /* adjust if necessary - all reasons */
2119 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2120 CPUFREQ_ADJUST, new_policy);
2123 * verify the cpu speed can be set within this limit, which might be
2124 * different to the first one
2126 ret = cpufreq_driver->verify(new_policy);
2130 /* notification of the new policy */
2131 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2132 CPUFREQ_NOTIFY, new_policy);
2134 policy->min = new_policy->min;
2135 policy->max = new_policy->max;
2137 pr_debug("new min and max freqs are %u - %u kHz\n",
2138 policy->min, policy->max);
2140 if (cpufreq_driver->setpolicy) {
2141 policy->policy = new_policy->policy;
2142 pr_debug("setting range\n");
2143 return cpufreq_driver->setpolicy(new_policy);
2146 if (new_policy->governor == policy->governor)
2149 pr_debug("governor switch\n");
2151 /* save old, working values */
2152 old_gov = policy->governor;
2153 /* end old governor */
2155 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2157 /* This can happen due to race with other operations */
2158 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2159 __func__, old_gov->name, ret);
2163 up_write(&policy->rwsem);
2164 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2165 down_write(&policy->rwsem);
2168 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2169 __func__, old_gov->name, ret);
2174 /* start new governor */
2175 policy->governor = new_policy->governor;
2176 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2178 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2182 up_write(&policy->rwsem);
2183 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2184 down_write(&policy->rwsem);
2187 /* new governor failed, so re-start old one */
2188 pr_debug("starting governor %s failed\n", policy->governor->name);
2190 policy->governor = old_gov;
2191 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2192 policy->governor = NULL;
2194 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2200 pr_debug("governor: change or update limits\n");
2201 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2205 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2206 * @cpu: CPU which shall be re-evaluated
2208 * Useful for policy notifiers which have different necessities
2209 * at different times.
2211 int cpufreq_update_policy(unsigned int cpu)
2213 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2214 struct cpufreq_policy new_policy;
2220 down_write(&policy->rwsem);
2222 pr_debug("updating policy for CPU %u\n", cpu);
2223 memcpy(&new_policy, policy, sizeof(*policy));
2224 new_policy.min = policy->user_policy.min;
2225 new_policy.max = policy->user_policy.max;
2228 * BIOS might change freq behind our back
2229 * -> ask driver for current freq and notify governors about a change
2231 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2232 new_policy.cur = cpufreq_driver->get(cpu);
2233 if (WARN_ON(!new_policy.cur)) {
2239 pr_debug("Driver did not initialize current freq\n");
2240 policy->cur = new_policy.cur;
2242 if (policy->cur != new_policy.cur && has_target())
2243 cpufreq_out_of_sync(policy, new_policy.cur);
2247 ret = cpufreq_set_policy(policy, &new_policy);
2250 up_write(&policy->rwsem);
2252 cpufreq_cpu_put(policy);
2255 EXPORT_SYMBOL(cpufreq_update_policy);
2257 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2258 unsigned long action, void *hcpu)
2260 unsigned int cpu = (unsigned long)hcpu;
2262 switch (action & ~CPU_TASKS_FROZEN) {
2264 cpufreq_online(cpu);
2267 case CPU_DOWN_PREPARE:
2268 cpufreq_offline_prepare(cpu);
2272 cpufreq_offline_finish(cpu);
2275 case CPU_DOWN_FAILED:
2276 cpufreq_online(cpu);
2282 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2283 .notifier_call = cpufreq_cpu_callback,
2286 /*********************************************************************
2288 *********************************************************************/
2289 static int cpufreq_boost_set_sw(int state)
2291 struct cpufreq_frequency_table *freq_table;
2292 struct cpufreq_policy *policy;
2295 for_each_active_policy(policy) {
2296 freq_table = cpufreq_frequency_get_table(policy->cpu);
2298 ret = cpufreq_frequency_table_cpuinfo(policy,
2301 pr_err("%s: Policy frequency update failed\n",
2305 policy->user_policy.max = policy->max;
2306 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2313 int cpufreq_boost_trigger_state(int state)
2315 unsigned long flags;
2318 if (cpufreq_driver->boost_enabled == state)
2321 write_lock_irqsave(&cpufreq_driver_lock, flags);
2322 cpufreq_driver->boost_enabled = state;
2323 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2325 ret = cpufreq_driver->set_boost(state);
2327 write_lock_irqsave(&cpufreq_driver_lock, flags);
2328 cpufreq_driver->boost_enabled = !state;
2329 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2331 pr_err("%s: Cannot %s BOOST\n",
2332 __func__, state ? "enable" : "disable");
2338 static bool cpufreq_boost_supported(void)
2340 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2343 static int create_boost_sysfs_file(void)
2347 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2349 pr_err("%s: cannot register global BOOST sysfs file\n",
2355 static void remove_boost_sysfs_file(void)
2357 if (cpufreq_boost_supported())
2358 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2361 int cpufreq_enable_boost_support(void)
2363 if (!cpufreq_driver)
2366 if (cpufreq_boost_supported())
2369 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2371 /* This will get removed on driver unregister */
2372 return create_boost_sysfs_file();
2374 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2376 int cpufreq_boost_enabled(void)
2378 return cpufreq_driver->boost_enabled;
2380 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2382 /*********************************************************************
2383 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2384 *********************************************************************/
2387 * cpufreq_register_driver - register a CPU Frequency driver
2388 * @driver_data: A struct cpufreq_driver containing the values#
2389 * submitted by the CPU Frequency driver.
2391 * Registers a CPU Frequency driver to this core code. This code
2392 * returns zero on success, -EBUSY when another driver got here first
2393 * (and isn't unregistered in the meantime).
2396 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2398 unsigned long flags;
2401 if (cpufreq_disabled())
2404 if (!driver_data || !driver_data->verify || !driver_data->init ||
2405 !(driver_data->setpolicy || driver_data->target_index ||
2406 driver_data->target) ||
2407 (driver_data->setpolicy && (driver_data->target_index ||
2408 driver_data->target)) ||
2409 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2412 pr_debug("trying to register driver %s\n", driver_data->name);
2414 /* Protect against concurrent CPU online/offline. */
2417 write_lock_irqsave(&cpufreq_driver_lock, flags);
2418 if (cpufreq_driver) {
2419 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2423 cpufreq_driver = driver_data;
2424 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2426 if (driver_data->setpolicy)
2427 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2429 if (cpufreq_boost_supported()) {
2430 ret = create_boost_sysfs_file();
2432 goto err_null_driver;
2435 ret = subsys_interface_register(&cpufreq_interface);
2437 goto err_boost_unreg;
2439 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2440 list_empty(&cpufreq_policy_list)) {
2441 /* if all ->init() calls failed, unregister */
2442 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2447 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2448 pr_debug("driver %s up and running\n", driver_data->name);
2455 subsys_interface_unregister(&cpufreq_interface);
2457 remove_boost_sysfs_file();
2459 write_lock_irqsave(&cpufreq_driver_lock, flags);
2460 cpufreq_driver = NULL;
2461 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2464 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2467 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2469 * Unregister the current CPUFreq driver. Only call this if you have
2470 * the right to do so, i.e. if you have succeeded in initialising before!
2471 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2472 * currently not initialised.
2474 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2476 unsigned long flags;
2478 if (!cpufreq_driver || (driver != cpufreq_driver))
2481 pr_debug("unregistering driver %s\n", driver->name);
2483 /* Protect against concurrent cpu hotplug */
2485 subsys_interface_unregister(&cpufreq_interface);
2486 remove_boost_sysfs_file();
2487 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2489 write_lock_irqsave(&cpufreq_driver_lock, flags);
2491 cpufreq_driver = NULL;
2493 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2498 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2501 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2502 * or mutexes when secondary CPUs are halted.
2504 static struct syscore_ops cpufreq_syscore_ops = {
2505 .shutdown = cpufreq_suspend,
2508 struct kobject *cpufreq_global_kobject;
2509 EXPORT_SYMBOL(cpufreq_global_kobject);
2511 static int __init cpufreq_core_init(void)
2513 if (cpufreq_disabled())
2516 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2517 BUG_ON(!cpufreq_global_kobject);
2519 register_syscore_ops(&cpufreq_syscore_ops);
2523 core_initcall(cpufreq_core_init);