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 /*********************************************************************
351 * FREQUENCY INVARIANT CPU CAPACITY *
352 *********************************************************************/
354 static DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
357 scale_freq_capacity(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs)
359 unsigned long cur = freqs ? freqs->new : policy->cur;
360 unsigned long scale = (cur << SCHED_CAPACITY_SHIFT) / policy->max;
363 pr_debug("cpus %*pbl cur/cur max freq %lu/%u kHz freq scale %lu\n",
364 cpumask_pr_args(policy->cpus), cur, policy->max, scale);
366 for_each_cpu(cpu, policy->cpus)
367 per_cpu(freq_scale, cpu) = scale;
370 unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu)
372 return per_cpu(freq_scale, cpu);
375 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
376 struct cpufreq_freqs *freqs, unsigned int state)
378 BUG_ON(irqs_disabled());
380 if (cpufreq_disabled())
383 freqs->flags = cpufreq_driver->flags;
384 pr_debug("notification %u of frequency transition to %u kHz\n",
389 case CPUFREQ_PRECHANGE:
390 /* detect if the driver reported a value as "old frequency"
391 * which is not equal to what the cpufreq core thinks is
394 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
395 if ((policy) && (policy->cpu == freqs->cpu) &&
396 (policy->cur) && (policy->cur != freqs->old)) {
397 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
398 freqs->old, policy->cur);
399 freqs->old = policy->cur;
402 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
403 CPUFREQ_PRECHANGE, freqs);
404 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
407 case CPUFREQ_POSTCHANGE:
408 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
409 pr_debug("FREQ: %lu - CPU: %lu\n",
410 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
411 trace_cpu_frequency(freqs->new, freqs->cpu);
412 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
413 CPUFREQ_POSTCHANGE, freqs);
414 if (likely(policy) && likely(policy->cpu == freqs->cpu))
415 policy->cur = freqs->new;
421 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
422 * on frequency transition.
424 * This function calls the transition notifiers and the "adjust_jiffies"
425 * function. It is called twice on all CPU frequency changes that have
428 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
429 struct cpufreq_freqs *freqs, unsigned int state)
431 for_each_cpu(freqs->cpu, policy->cpus)
432 __cpufreq_notify_transition(policy, freqs, state);
435 /* Do post notifications when there are chances that transition has failed */
436 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
437 struct cpufreq_freqs *freqs, int transition_failed)
439 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
440 if (!transition_failed)
443 swap(freqs->old, freqs->new);
444 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
445 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
448 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
449 struct cpufreq_freqs *freqs)
453 * Catch double invocations of _begin() which lead to self-deadlock.
454 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
455 * doesn't invoke _begin() on their behalf, and hence the chances of
456 * double invocations are very low. Moreover, there are scenarios
457 * where these checks can emit false-positive warnings in these
458 * drivers; so we avoid that by skipping them altogether.
460 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
461 && current == policy->transition_task);
464 wait_event(policy->transition_wait, !policy->transition_ongoing);
466 spin_lock(&policy->transition_lock);
468 if (unlikely(policy->transition_ongoing)) {
469 spin_unlock(&policy->transition_lock);
473 policy->transition_ongoing = true;
474 policy->transition_task = current;
476 spin_unlock(&policy->transition_lock);
478 scale_freq_capacity(policy, freqs);
480 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
482 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
484 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
485 struct cpufreq_freqs *freqs, int transition_failed)
487 if (unlikely(WARN_ON(!policy->transition_ongoing)))
490 cpufreq_notify_post_transition(policy, freqs, transition_failed);
492 policy->transition_ongoing = false;
493 policy->transition_task = NULL;
495 wake_up(&policy->transition_wait);
497 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
500 /*********************************************************************
502 *********************************************************************/
503 static ssize_t show_boost(struct kobject *kobj,
504 struct attribute *attr, char *buf)
506 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
509 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
510 const char *buf, size_t count)
514 ret = sscanf(buf, "%d", &enable);
515 if (ret != 1 || enable < 0 || enable > 1)
518 if (cpufreq_boost_trigger_state(enable)) {
519 pr_err("%s: Cannot %s BOOST!\n",
520 __func__, enable ? "enable" : "disable");
524 pr_debug("%s: cpufreq BOOST %s\n",
525 __func__, enable ? "enabled" : "disabled");
529 define_one_global_rw(boost);
531 static struct cpufreq_governor *find_governor(const char *str_governor)
533 struct cpufreq_governor *t;
536 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
543 * cpufreq_parse_governor - parse a governor string
545 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
546 struct cpufreq_governor **governor)
550 if (cpufreq_driver->setpolicy) {
551 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
552 *policy = CPUFREQ_POLICY_PERFORMANCE;
554 } else if (!strncasecmp(str_governor, "powersave",
556 *policy = CPUFREQ_POLICY_POWERSAVE;
560 struct cpufreq_governor *t;
562 mutex_lock(&cpufreq_governor_mutex);
564 t = find_governor(str_governor);
569 mutex_unlock(&cpufreq_governor_mutex);
570 ret = request_module("cpufreq_%s", str_governor);
571 mutex_lock(&cpufreq_governor_mutex);
574 t = find_governor(str_governor);
582 mutex_unlock(&cpufreq_governor_mutex);
588 * cpufreq_per_cpu_attr_read() / show_##file_name() -
589 * print out cpufreq information
591 * Write out information from cpufreq_driver->policy[cpu]; object must be
595 #define show_one(file_name, object) \
596 static ssize_t show_##file_name \
597 (struct cpufreq_policy *policy, char *buf) \
599 return sprintf(buf, "%u\n", policy->object); \
602 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
603 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
604 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
605 show_one(scaling_min_freq, min);
606 show_one(scaling_max_freq, max);
608 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
612 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
613 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
615 ret = sprintf(buf, "%u\n", policy->cur);
619 static int cpufreq_set_policy(struct cpufreq_policy *policy,
620 struct cpufreq_policy *new_policy);
623 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
625 #define store_one(file_name, object) \
626 static ssize_t store_##file_name \
627 (struct cpufreq_policy *policy, const char *buf, size_t count) \
630 struct cpufreq_policy new_policy; \
632 memcpy(&new_policy, policy, sizeof(*policy)); \
634 ret = sscanf(buf, "%u", &new_policy.object); \
638 temp = new_policy.object; \
639 ret = cpufreq_set_policy(policy, &new_policy); \
641 policy->user_policy.object = temp; \
643 return ret ? ret : count; \
646 store_one(scaling_min_freq, min);
647 store_one(scaling_max_freq, max);
650 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
652 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
655 unsigned int cur_freq = __cpufreq_get(policy);
657 return sprintf(buf, "<unknown>");
658 return sprintf(buf, "%u\n", cur_freq);
662 * show_scaling_governor - show the current policy for the specified CPU
664 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
666 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
667 return sprintf(buf, "powersave\n");
668 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
669 return sprintf(buf, "performance\n");
670 else if (policy->governor)
671 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
672 policy->governor->name);
677 * store_scaling_governor - store policy for the specified CPU
679 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
680 const char *buf, size_t count)
683 char str_governor[16];
684 struct cpufreq_policy new_policy;
686 memcpy(&new_policy, policy, sizeof(*policy));
688 ret = sscanf(buf, "%15s", str_governor);
692 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
693 &new_policy.governor))
696 ret = cpufreq_set_policy(policy, &new_policy);
697 return ret ? ret : count;
701 * show_scaling_driver - show the cpufreq driver currently loaded
703 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
705 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
709 * show_scaling_available_governors - show the available CPUfreq governors
711 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
715 struct cpufreq_governor *t;
718 i += sprintf(buf, "performance powersave");
722 for_each_governor(t) {
723 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
724 - (CPUFREQ_NAME_LEN + 2)))
726 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
729 i += sprintf(&buf[i], "\n");
733 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
738 for_each_cpu(cpu, mask) {
740 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
741 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
742 if (i >= (PAGE_SIZE - 5))
745 i += sprintf(&buf[i], "\n");
748 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
751 * show_related_cpus - show the CPUs affected by each transition even if
752 * hw coordination is in use
754 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
756 return cpufreq_show_cpus(policy->related_cpus, buf);
760 * show_affected_cpus - show the CPUs affected by each transition
762 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
764 return cpufreq_show_cpus(policy->cpus, buf);
767 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
768 const char *buf, size_t count)
770 unsigned int freq = 0;
773 if (!policy->governor || !policy->governor->store_setspeed)
776 ret = sscanf(buf, "%u", &freq);
780 policy->governor->store_setspeed(policy, freq);
785 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
787 if (!policy->governor || !policy->governor->show_setspeed)
788 return sprintf(buf, "<unsupported>\n");
790 return policy->governor->show_setspeed(policy, buf);
794 * show_bios_limit - show the current cpufreq HW/BIOS limitation
796 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
800 if (cpufreq_driver->bios_limit) {
801 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
803 return sprintf(buf, "%u\n", limit);
805 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
808 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
809 cpufreq_freq_attr_ro(cpuinfo_min_freq);
810 cpufreq_freq_attr_ro(cpuinfo_max_freq);
811 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
812 cpufreq_freq_attr_ro(scaling_available_governors);
813 cpufreq_freq_attr_ro(scaling_driver);
814 cpufreq_freq_attr_ro(scaling_cur_freq);
815 cpufreq_freq_attr_ro(bios_limit);
816 cpufreq_freq_attr_ro(related_cpus);
817 cpufreq_freq_attr_ro(affected_cpus);
818 cpufreq_freq_attr_rw(scaling_min_freq);
819 cpufreq_freq_attr_rw(scaling_max_freq);
820 cpufreq_freq_attr_rw(scaling_governor);
821 cpufreq_freq_attr_rw(scaling_setspeed);
823 static struct attribute *default_attrs[] = {
824 &cpuinfo_min_freq.attr,
825 &cpuinfo_max_freq.attr,
826 &cpuinfo_transition_latency.attr,
827 &scaling_min_freq.attr,
828 &scaling_max_freq.attr,
831 &scaling_governor.attr,
832 &scaling_driver.attr,
833 &scaling_available_governors.attr,
834 &scaling_setspeed.attr,
838 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
839 #define to_attr(a) container_of(a, struct freq_attr, attr)
841 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
843 struct cpufreq_policy *policy = to_policy(kobj);
844 struct freq_attr *fattr = to_attr(attr);
847 down_read(&policy->rwsem);
850 ret = fattr->show(policy, buf);
854 up_read(&policy->rwsem);
859 static ssize_t store(struct kobject *kobj, struct attribute *attr,
860 const char *buf, size_t count)
862 struct cpufreq_policy *policy = to_policy(kobj);
863 struct freq_attr *fattr = to_attr(attr);
864 ssize_t ret = -EINVAL;
868 if (!cpu_online(policy->cpu))
871 down_write(&policy->rwsem);
874 ret = fattr->store(policy, buf, count);
878 up_write(&policy->rwsem);
885 static void cpufreq_sysfs_release(struct kobject *kobj)
887 struct cpufreq_policy *policy = to_policy(kobj);
888 pr_debug("last reference is dropped\n");
889 complete(&policy->kobj_unregister);
892 static const struct sysfs_ops sysfs_ops = {
897 static struct kobj_type ktype_cpufreq = {
898 .sysfs_ops = &sysfs_ops,
899 .default_attrs = default_attrs,
900 .release = cpufreq_sysfs_release,
903 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
905 struct device *cpu_dev;
907 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
912 cpu_dev = get_cpu_device(cpu);
913 if (WARN_ON(!cpu_dev))
916 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
919 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
921 struct device *cpu_dev;
923 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
925 cpu_dev = get_cpu_device(cpu);
926 if (WARN_ON(!cpu_dev))
929 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
932 /* Add/remove symlinks for all related CPUs */
933 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
938 /* Some related CPUs might not be present (physically hotplugged) */
939 for_each_cpu(j, policy->real_cpus) {
940 ret = add_cpu_dev_symlink(policy, j);
948 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
952 /* Some related CPUs might not be present (physically hotplugged) */
953 for_each_cpu(j, policy->real_cpus)
954 remove_cpu_dev_symlink(policy, j);
957 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
959 struct freq_attr **drv_attr;
962 /* set up files for this cpu device */
963 drv_attr = cpufreq_driver->attr;
964 while (drv_attr && *drv_attr) {
965 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
970 if (cpufreq_driver->get) {
971 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
976 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
980 if (cpufreq_driver->bios_limit) {
981 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
986 return cpufreq_add_dev_symlink(policy);
989 static int cpufreq_init_policy(struct cpufreq_policy *policy)
991 struct cpufreq_governor *gov = NULL;
992 struct cpufreq_policy new_policy;
994 memcpy(&new_policy, policy, sizeof(*policy));
996 /* Update governor of new_policy to the governor used before hotplug */
997 gov = find_governor(policy->last_governor);
999 pr_debug("Restoring governor %s for cpu %d\n",
1000 policy->governor->name, policy->cpu);
1002 gov = CPUFREQ_DEFAULT_GOVERNOR;
1004 new_policy.governor = gov;
1006 /* Use the default policy if there is no last_policy. */
1007 if (cpufreq_driver->setpolicy) {
1008 if (policy->last_policy)
1009 new_policy.policy = policy->last_policy;
1011 cpufreq_parse_governor(gov->name, &new_policy.policy,
1014 /* set default policy */
1015 return cpufreq_set_policy(policy, &new_policy);
1018 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1022 /* Has this CPU been taken care of already? */
1023 if (cpumask_test_cpu(cpu, policy->cpus))
1027 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1029 pr_err("%s: Failed to stop governor\n", __func__);
1034 down_write(&policy->rwsem);
1035 cpumask_set_cpu(cpu, policy->cpus);
1036 up_write(&policy->rwsem);
1039 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1041 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1044 pr_err("%s: Failed to start governor\n", __func__);
1052 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1054 struct device *dev = get_cpu_device(cpu);
1055 struct cpufreq_policy *policy;
1060 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1064 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1065 goto err_free_policy;
1067 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1068 goto err_free_cpumask;
1070 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1071 goto err_free_rcpumask;
1073 kobject_init(&policy->kobj, &ktype_cpufreq);
1074 INIT_LIST_HEAD(&policy->policy_list);
1075 init_rwsem(&policy->rwsem);
1076 spin_lock_init(&policy->transition_lock);
1077 init_waitqueue_head(&policy->transition_wait);
1078 init_completion(&policy->kobj_unregister);
1079 INIT_WORK(&policy->update, handle_update);
1085 free_cpumask_var(policy->related_cpus);
1087 free_cpumask_var(policy->cpus);
1094 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1096 struct kobject *kobj;
1097 struct completion *cmp;
1100 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1101 CPUFREQ_REMOVE_POLICY, policy);
1103 down_write(&policy->rwsem);
1104 cpufreq_remove_dev_symlink(policy);
1105 kobj = &policy->kobj;
1106 cmp = &policy->kobj_unregister;
1107 up_write(&policy->rwsem);
1111 * We need to make sure that the underlying kobj is
1112 * actually not referenced anymore by anybody before we
1113 * proceed with unloading.
1115 pr_debug("waiting for dropping of refcount\n");
1116 wait_for_completion(cmp);
1117 pr_debug("wait complete\n");
1120 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1122 unsigned long flags;
1125 /* Remove policy from list */
1126 write_lock_irqsave(&cpufreq_driver_lock, flags);
1127 list_del(&policy->policy_list);
1129 for_each_cpu(cpu, policy->related_cpus)
1130 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1131 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1133 cpufreq_policy_put_kobj(policy, notify);
1134 free_cpumask_var(policy->real_cpus);
1135 free_cpumask_var(policy->related_cpus);
1136 free_cpumask_var(policy->cpus);
1140 static int cpufreq_online(unsigned int cpu)
1142 struct cpufreq_policy *policy;
1144 unsigned long flags;
1148 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1150 /* Check if this CPU already has a policy to manage it */
1151 policy = per_cpu(cpufreq_cpu_data, cpu);
1153 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1154 if (!policy_is_inactive(policy))
1155 return cpufreq_add_policy_cpu(policy, cpu);
1157 /* This is the only online CPU for the policy. Start over. */
1159 down_write(&policy->rwsem);
1161 policy->governor = NULL;
1162 up_write(&policy->rwsem);
1165 policy = cpufreq_policy_alloc(cpu);
1170 cpumask_copy(policy->cpus, cpumask_of(cpu));
1172 /* call driver. From then on the cpufreq must be able
1173 * to accept all calls to ->verify and ->setpolicy for this CPU
1175 ret = cpufreq_driver->init(policy);
1177 pr_debug("initialization failed\n");
1178 goto out_free_policy;
1181 down_write(&policy->rwsem);
1184 /* related_cpus should at least include policy->cpus. */
1185 cpumask_copy(policy->related_cpus, policy->cpus);
1186 /* Remember CPUs present at the policy creation time. */
1187 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1189 /* Name and add the kobject */
1190 ret = kobject_add(&policy->kobj, cpufreq_global_kobject,
1192 cpumask_first(policy->related_cpus));
1194 pr_err("%s: failed to add policy->kobj: %d\n", __func__,
1196 goto out_exit_policy;
1201 * affected cpus must always be the one, which are online. We aren't
1202 * managing offline cpus here.
1204 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1207 policy->user_policy.min = policy->min;
1208 policy->user_policy.max = policy->max;
1210 write_lock_irqsave(&cpufreq_driver_lock, flags);
1211 for_each_cpu(j, policy->related_cpus)
1212 per_cpu(cpufreq_cpu_data, j) = policy;
1213 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1216 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1217 policy->cur = cpufreq_driver->get(policy->cpu);
1219 pr_err("%s: ->get() failed\n", __func__);
1220 goto out_exit_policy;
1225 * Sometimes boot loaders set CPU frequency to a value outside of
1226 * frequency table present with cpufreq core. In such cases CPU might be
1227 * unstable if it has to run on that frequency for long duration of time
1228 * and so its better to set it to a frequency which is specified in
1229 * freq-table. This also makes cpufreq stats inconsistent as
1230 * cpufreq-stats would fail to register because current frequency of CPU
1231 * isn't found in freq-table.
1233 * Because we don't want this change to effect boot process badly, we go
1234 * for the next freq which is >= policy->cur ('cur' must be set by now,
1235 * otherwise we will end up setting freq to lowest of the table as 'cur'
1236 * is initialized to zero).
1238 * We are passing target-freq as "policy->cur - 1" otherwise
1239 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1240 * equal to target-freq.
1242 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1244 /* Are we running at unknown frequency ? */
1245 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1246 if (ret == -EINVAL) {
1247 /* Warn user and fix it */
1248 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1249 __func__, policy->cpu, policy->cur);
1250 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1251 CPUFREQ_RELATION_L);
1254 * Reaching here after boot in a few seconds may not
1255 * mean that system will remain stable at "unknown"
1256 * frequency for longer duration. Hence, a BUG_ON().
1259 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1260 __func__, policy->cpu, policy->cur);
1264 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1265 CPUFREQ_START, policy);
1268 ret = cpufreq_add_dev_interface(policy);
1270 goto out_exit_policy;
1271 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1272 CPUFREQ_CREATE_POLICY, policy);
1274 write_lock_irqsave(&cpufreq_driver_lock, flags);
1275 list_add(&policy->policy_list, &cpufreq_policy_list);
1276 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1279 ret = cpufreq_init_policy(policy);
1281 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1282 __func__, cpu, ret);
1283 /* cpufreq_policy_free() will notify based on this */
1285 goto out_exit_policy;
1288 up_write(&policy->rwsem);
1290 kobject_uevent(&policy->kobj, KOBJ_ADD);
1292 /* Callback for handling stuff after policy is ready */
1293 if (cpufreq_driver->ready)
1294 cpufreq_driver->ready(policy);
1296 pr_debug("initialization complete\n");
1301 up_write(&policy->rwsem);
1303 if (cpufreq_driver->exit)
1304 cpufreq_driver->exit(policy);
1306 cpufreq_policy_free(policy, !new_policy);
1311 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1313 * @sif: Subsystem interface structure pointer (not used)
1315 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1317 unsigned cpu = dev->id;
1320 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1322 if (cpu_online(cpu)) {
1323 ret = cpufreq_online(cpu);
1326 * A hotplug notifier will follow and we will handle it as CPU
1327 * online then. For now, just create the sysfs link, unless
1328 * there is no policy or the link is already present.
1330 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1332 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1333 ? add_cpu_dev_symlink(policy, cpu) : 0;
1339 static void cpufreq_offline_prepare(unsigned int cpu)
1341 struct cpufreq_policy *policy;
1343 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1345 policy = cpufreq_cpu_get_raw(cpu);
1347 pr_debug("%s: No cpu_data found\n", __func__);
1352 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1354 pr_err("%s: Failed to stop governor\n", __func__);
1357 down_write(&policy->rwsem);
1358 cpumask_clear_cpu(cpu, policy->cpus);
1360 if (policy_is_inactive(policy)) {
1362 strncpy(policy->last_governor, policy->governor->name,
1365 policy->last_policy = policy->policy;
1366 } else if (cpu == policy->cpu) {
1367 /* Nominate new CPU */
1368 policy->cpu = cpumask_any(policy->cpus);
1370 up_write(&policy->rwsem);
1372 /* Start governor again for active policy */
1373 if (!policy_is_inactive(policy)) {
1375 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1377 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1380 pr_err("%s: Failed to start governor\n", __func__);
1382 } else if (cpufreq_driver->stop_cpu) {
1383 cpufreq_driver->stop_cpu(policy);
1387 static void cpufreq_offline_finish(unsigned int cpu)
1389 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1392 pr_debug("%s: No cpu_data found\n", __func__);
1396 /* Only proceed for inactive policies */
1397 if (!policy_is_inactive(policy))
1400 /* If cpu is last user of policy, free policy */
1402 int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1404 pr_err("%s: Failed to exit governor\n", __func__);
1408 * Perform the ->exit() even during light-weight tear-down,
1409 * since this is a core component, and is essential for the
1410 * subsequent light-weight ->init() to succeed.
1412 if (cpufreq_driver->exit) {
1413 cpufreq_driver->exit(policy);
1414 policy->freq_table = NULL;
1419 * cpufreq_remove_dev - remove a CPU device
1421 * Removes the cpufreq interface for a CPU device.
1423 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1425 unsigned int cpu = dev->id;
1426 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1431 if (cpu_online(cpu)) {
1432 cpufreq_offline_prepare(cpu);
1433 cpufreq_offline_finish(cpu);
1436 cpumask_clear_cpu(cpu, policy->real_cpus);
1437 remove_cpu_dev_symlink(policy, cpu);
1439 if (cpumask_empty(policy->real_cpus))
1440 cpufreq_policy_free(policy, true);
1443 static void handle_update(struct work_struct *work)
1445 struct cpufreq_policy *policy =
1446 container_of(work, struct cpufreq_policy, update);
1447 unsigned int cpu = policy->cpu;
1448 pr_debug("handle_update for cpu %u called\n", cpu);
1449 cpufreq_update_policy(cpu);
1453 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1455 * @policy: policy managing CPUs
1456 * @new_freq: CPU frequency the CPU actually runs at
1458 * We adjust to current frequency first, and need to clean up later.
1459 * So either call to cpufreq_update_policy() or schedule handle_update()).
1461 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1462 unsigned int new_freq)
1464 struct cpufreq_freqs freqs;
1466 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1467 policy->cur, new_freq);
1469 freqs.old = policy->cur;
1470 freqs.new = new_freq;
1472 cpufreq_freq_transition_begin(policy, &freqs);
1473 cpufreq_freq_transition_end(policy, &freqs, 0);
1477 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1480 * This is the last known freq, without actually getting it from the driver.
1481 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1483 unsigned int cpufreq_quick_get(unsigned int cpu)
1485 struct cpufreq_policy *policy;
1486 unsigned int ret_freq = 0;
1488 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1489 return cpufreq_driver->get(cpu);
1491 policy = cpufreq_cpu_get(cpu);
1493 ret_freq = policy->cur;
1494 cpufreq_cpu_put(policy);
1499 EXPORT_SYMBOL(cpufreq_quick_get);
1502 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1505 * Just return the max possible frequency for a given CPU.
1507 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1509 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1510 unsigned int ret_freq = 0;
1513 ret_freq = policy->max;
1514 cpufreq_cpu_put(policy);
1519 EXPORT_SYMBOL(cpufreq_quick_get_max);
1521 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1523 unsigned int ret_freq = 0;
1525 if (!cpufreq_driver->get)
1528 ret_freq = cpufreq_driver->get(policy->cpu);
1530 /* Updating inactive policies is invalid, so avoid doing that. */
1531 if (unlikely(policy_is_inactive(policy)))
1534 if (ret_freq && policy->cur &&
1535 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1536 /* verify no discrepancy between actual and
1537 saved value exists */
1538 if (unlikely(ret_freq != policy->cur)) {
1539 cpufreq_out_of_sync(policy, ret_freq);
1540 schedule_work(&policy->update);
1548 * cpufreq_get - get the current CPU frequency (in kHz)
1551 * Get the CPU current (static) CPU frequency
1553 unsigned int cpufreq_get(unsigned int cpu)
1555 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1556 unsigned int ret_freq = 0;
1559 down_read(&policy->rwsem);
1560 ret_freq = __cpufreq_get(policy);
1561 up_read(&policy->rwsem);
1563 cpufreq_cpu_put(policy);
1568 EXPORT_SYMBOL(cpufreq_get);
1570 static struct subsys_interface cpufreq_interface = {
1572 .subsys = &cpu_subsys,
1573 .add_dev = cpufreq_add_dev,
1574 .remove_dev = cpufreq_remove_dev,
1578 * In case platform wants some specific frequency to be configured
1581 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1585 if (!policy->suspend_freq) {
1586 pr_debug("%s: suspend_freq not defined\n", __func__);
1590 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1591 policy->suspend_freq);
1593 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1594 CPUFREQ_RELATION_H);
1596 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1597 __func__, policy->suspend_freq, ret);
1601 EXPORT_SYMBOL(cpufreq_generic_suspend);
1604 * cpufreq_suspend() - Suspend CPUFreq governors
1606 * Called during system wide Suspend/Hibernate cycles for suspending governors
1607 * as some platforms can't change frequency after this point in suspend cycle.
1608 * Because some of the devices (like: i2c, regulators, etc) they use for
1609 * changing frequency are suspended quickly after this point.
1611 void cpufreq_suspend(void)
1613 struct cpufreq_policy *policy;
1615 if (!cpufreq_driver)
1621 pr_debug("%s: Suspending Governors\n", __func__);
1623 for_each_active_policy(policy) {
1624 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1625 pr_err("%s: Failed to stop governor for policy: %p\n",
1627 else if (cpufreq_driver->suspend
1628 && cpufreq_driver->suspend(policy))
1629 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1634 cpufreq_suspended = true;
1638 * cpufreq_resume() - Resume CPUFreq governors
1640 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1641 * are suspended with cpufreq_suspend().
1643 void cpufreq_resume(void)
1645 struct cpufreq_policy *policy;
1647 if (!cpufreq_driver)
1650 cpufreq_suspended = false;
1655 pr_debug("%s: Resuming Governors\n", __func__);
1657 for_each_active_policy(policy) {
1658 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1659 pr_err("%s: Failed to resume driver: %p\n", __func__,
1661 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1662 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1663 pr_err("%s: Failed to start governor for policy: %p\n",
1668 * schedule call cpufreq_update_policy() for first-online CPU, as that
1669 * wouldn't be hotplugged-out on suspend. It will verify that the
1670 * current freq is in sync with what we believe it to be.
1672 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1673 if (WARN_ON(!policy))
1676 schedule_work(&policy->update);
1680 * cpufreq_get_current_driver - return current driver's name
1682 * Return the name string of the currently loaded cpufreq driver
1685 const char *cpufreq_get_current_driver(void)
1688 return cpufreq_driver->name;
1692 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1695 * cpufreq_get_driver_data - return current driver data
1697 * Return the private data of the currently loaded cpufreq
1698 * driver, or NULL if no cpufreq driver is loaded.
1700 void *cpufreq_get_driver_data(void)
1703 return cpufreq_driver->driver_data;
1707 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1709 /*********************************************************************
1710 * NOTIFIER LISTS INTERFACE *
1711 *********************************************************************/
1714 * cpufreq_register_notifier - register a driver with cpufreq
1715 * @nb: notifier function to register
1716 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1718 * Add a driver to one of two lists: either a list of drivers that
1719 * are notified about clock rate changes (once before and once after
1720 * the transition), or a list of drivers that are notified about
1721 * changes in cpufreq policy.
1723 * This function may sleep, and has the same return conditions as
1724 * blocking_notifier_chain_register.
1726 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1730 if (cpufreq_disabled())
1733 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1736 case CPUFREQ_TRANSITION_NOTIFIER:
1737 ret = srcu_notifier_chain_register(
1738 &cpufreq_transition_notifier_list, nb);
1740 case CPUFREQ_POLICY_NOTIFIER:
1741 ret = blocking_notifier_chain_register(
1742 &cpufreq_policy_notifier_list, nb);
1750 EXPORT_SYMBOL(cpufreq_register_notifier);
1753 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1754 * @nb: notifier block to be unregistered
1755 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1757 * Remove a driver from the CPU frequency notifier list.
1759 * This function may sleep, and has the same return conditions as
1760 * blocking_notifier_chain_unregister.
1762 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1766 if (cpufreq_disabled())
1770 case CPUFREQ_TRANSITION_NOTIFIER:
1771 ret = srcu_notifier_chain_unregister(
1772 &cpufreq_transition_notifier_list, nb);
1774 case CPUFREQ_POLICY_NOTIFIER:
1775 ret = blocking_notifier_chain_unregister(
1776 &cpufreq_policy_notifier_list, nb);
1784 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1787 /*********************************************************************
1789 *********************************************************************/
1791 /* Must set freqs->new to intermediate frequency */
1792 static int __target_intermediate(struct cpufreq_policy *policy,
1793 struct cpufreq_freqs *freqs, int index)
1797 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1799 /* We don't need to switch to intermediate freq */
1803 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1804 __func__, policy->cpu, freqs->old, freqs->new);
1806 cpufreq_freq_transition_begin(policy, freqs);
1807 ret = cpufreq_driver->target_intermediate(policy, index);
1808 cpufreq_freq_transition_end(policy, freqs, ret);
1811 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1817 static int __target_index(struct cpufreq_policy *policy,
1818 struct cpufreq_frequency_table *freq_table, int index)
1820 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1821 unsigned int intermediate_freq = 0;
1822 int retval = -EINVAL;
1825 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1827 /* Handle switching to intermediate frequency */
1828 if (cpufreq_driver->get_intermediate) {
1829 retval = __target_intermediate(policy, &freqs, index);
1833 intermediate_freq = freqs.new;
1834 /* Set old freq to intermediate */
1835 if (intermediate_freq)
1836 freqs.old = freqs.new;
1839 freqs.new = freq_table[index].frequency;
1840 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1841 __func__, policy->cpu, freqs.old, freqs.new);
1843 cpufreq_freq_transition_begin(policy, &freqs);
1846 retval = cpufreq_driver->target_index(policy, index);
1848 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1852 cpufreq_freq_transition_end(policy, &freqs, retval);
1855 * Failed after setting to intermediate freq? Driver should have
1856 * reverted back to initial frequency and so should we. Check
1857 * here for intermediate_freq instead of get_intermediate, in
1858 * case we haven't switched to intermediate freq at all.
1860 if (unlikely(retval && intermediate_freq)) {
1861 freqs.old = intermediate_freq;
1862 freqs.new = policy->restore_freq;
1863 cpufreq_freq_transition_begin(policy, &freqs);
1864 cpufreq_freq_transition_end(policy, &freqs, 0);
1871 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1872 unsigned int target_freq,
1873 unsigned int relation)
1875 unsigned int old_target_freq = target_freq;
1876 int retval = -EINVAL;
1878 if (cpufreq_disabled())
1881 /* Make sure that target_freq is within supported range */
1882 if (target_freq > policy->max)
1883 target_freq = policy->max;
1884 if (target_freq < policy->min)
1885 target_freq = policy->min;
1887 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1888 policy->cpu, target_freq, relation, old_target_freq);
1891 * This might look like a redundant call as we are checking it again
1892 * after finding index. But it is left intentionally for cases where
1893 * exactly same freq is called again and so we can save on few function
1896 if (target_freq == policy->cur)
1899 /* Save last value to restore later on errors */
1900 policy->restore_freq = policy->cur;
1902 if (cpufreq_driver->target)
1903 retval = cpufreq_driver->target(policy, target_freq, relation);
1904 else if (cpufreq_driver->target_index) {
1905 struct cpufreq_frequency_table *freq_table;
1908 freq_table = cpufreq_frequency_get_table(policy->cpu);
1909 if (unlikely(!freq_table)) {
1910 pr_err("%s: Unable to find freq_table\n", __func__);
1914 retval = cpufreq_frequency_table_target(policy, freq_table,
1915 target_freq, relation, &index);
1916 if (unlikely(retval)) {
1917 pr_err("%s: Unable to find matching freq\n", __func__);
1921 if (freq_table[index].frequency == policy->cur) {
1926 retval = __target_index(policy, freq_table, index);
1932 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1934 int cpufreq_driver_target(struct cpufreq_policy *policy,
1935 unsigned int target_freq,
1936 unsigned int relation)
1940 down_write(&policy->rwsem);
1942 ret = __cpufreq_driver_target(policy, target_freq, relation);
1944 up_write(&policy->rwsem);
1948 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1950 static int __cpufreq_governor(struct cpufreq_policy *policy,
1955 /* Only must be defined when default governor is known to have latency
1956 restrictions, like e.g. conservative or ondemand.
1957 That this is the case is already ensured in Kconfig
1959 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1960 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1962 struct cpufreq_governor *gov = NULL;
1965 /* Don't start any governor operations if we are entering suspend */
1966 if (cpufreq_suspended)
1969 * Governor might not be initiated here if ACPI _PPC changed
1970 * notification happened, so check it.
1972 if (!policy->governor)
1975 if (policy->governor->max_transition_latency &&
1976 policy->cpuinfo.transition_latency >
1977 policy->governor->max_transition_latency) {
1981 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1982 policy->governor->name, gov->name);
1983 policy->governor = gov;
1987 if (event == CPUFREQ_GOV_POLICY_INIT)
1988 if (!try_module_get(policy->governor->owner))
1991 pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
1993 mutex_lock(&cpufreq_governor_lock);
1994 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1995 || (!policy->governor_enabled
1996 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1997 mutex_unlock(&cpufreq_governor_lock);
2001 if (event == CPUFREQ_GOV_STOP)
2002 policy->governor_enabled = false;
2003 else if (event == CPUFREQ_GOV_START)
2004 policy->governor_enabled = true;
2006 mutex_unlock(&cpufreq_governor_lock);
2008 ret = policy->governor->governor(policy, event);
2011 if (event == CPUFREQ_GOV_POLICY_INIT)
2012 policy->governor->initialized++;
2013 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2014 policy->governor->initialized--;
2016 /* Restore original values */
2017 mutex_lock(&cpufreq_governor_lock);
2018 if (event == CPUFREQ_GOV_STOP)
2019 policy->governor_enabled = true;
2020 else if (event == CPUFREQ_GOV_START)
2021 policy->governor_enabled = false;
2022 mutex_unlock(&cpufreq_governor_lock);
2025 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2026 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2027 module_put(policy->governor->owner);
2032 int cpufreq_register_governor(struct cpufreq_governor *governor)
2039 if (cpufreq_disabled())
2042 mutex_lock(&cpufreq_governor_mutex);
2044 governor->initialized = 0;
2046 if (!find_governor(governor->name)) {
2048 list_add(&governor->governor_list, &cpufreq_governor_list);
2051 mutex_unlock(&cpufreq_governor_mutex);
2054 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2056 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2058 struct cpufreq_policy *policy;
2059 unsigned long flags;
2064 if (cpufreq_disabled())
2067 /* clear last_governor for all inactive policies */
2068 read_lock_irqsave(&cpufreq_driver_lock, flags);
2069 for_each_inactive_policy(policy) {
2070 if (!strcmp(policy->last_governor, governor->name)) {
2071 policy->governor = NULL;
2072 strcpy(policy->last_governor, "\0");
2075 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2077 mutex_lock(&cpufreq_governor_mutex);
2078 list_del(&governor->governor_list);
2079 mutex_unlock(&cpufreq_governor_mutex);
2082 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2085 /*********************************************************************
2086 * POLICY INTERFACE *
2087 *********************************************************************/
2090 * cpufreq_get_policy - get the current cpufreq_policy
2091 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2094 * Reads the current cpufreq policy.
2096 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2098 struct cpufreq_policy *cpu_policy;
2102 cpu_policy = cpufreq_cpu_get(cpu);
2106 memcpy(policy, cpu_policy, sizeof(*policy));
2108 cpufreq_cpu_put(cpu_policy);
2111 EXPORT_SYMBOL(cpufreq_get_policy);
2114 * policy : current policy.
2115 * new_policy: policy to be set.
2117 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2118 struct cpufreq_policy *new_policy)
2120 struct cpufreq_governor *old_gov;
2123 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2124 new_policy->cpu, new_policy->min, new_policy->max);
2126 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2129 * This check works well when we store new min/max freq attributes,
2130 * because new_policy is a copy of policy with one field updated.
2132 if (new_policy->min > new_policy->max)
2135 /* verify the cpu speed can be set within this limit */
2136 ret = cpufreq_driver->verify(new_policy);
2140 /* adjust if necessary - all reasons */
2141 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2142 CPUFREQ_ADJUST, new_policy);
2145 * verify the cpu speed can be set within this limit, which might be
2146 * different to the first one
2148 ret = cpufreq_driver->verify(new_policy);
2152 /* notification of the new policy */
2153 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2154 CPUFREQ_NOTIFY, new_policy);
2156 scale_freq_capacity(new_policy, NULL);
2158 policy->min = new_policy->min;
2159 policy->max = new_policy->max;
2161 pr_debug("new min and max freqs are %u - %u kHz\n",
2162 policy->min, policy->max);
2164 if (cpufreq_driver->setpolicy) {
2165 policy->policy = new_policy->policy;
2166 pr_debug("setting range\n");
2167 return cpufreq_driver->setpolicy(new_policy);
2170 if (new_policy->governor == policy->governor)
2173 pr_debug("governor switch\n");
2175 /* save old, working values */
2176 old_gov = policy->governor;
2177 /* end old governor */
2179 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2181 /* This can happen due to race with other operations */
2182 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2183 __func__, old_gov->name, ret);
2187 up_write(&policy->rwsem);
2188 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2189 down_write(&policy->rwsem);
2192 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2193 __func__, old_gov->name, ret);
2198 /* start new governor */
2199 policy->governor = new_policy->governor;
2200 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2202 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
2206 up_write(&policy->rwsem);
2207 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2208 down_write(&policy->rwsem);
2211 /* new governor failed, so re-start old one */
2212 pr_debug("starting governor %s failed\n", policy->governor->name);
2214 policy->governor = old_gov;
2215 if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2216 policy->governor = NULL;
2218 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2224 pr_debug("governor: change or update limits\n");
2225 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2229 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2230 * @cpu: CPU which shall be re-evaluated
2232 * Useful for policy notifiers which have different necessities
2233 * at different times.
2235 int cpufreq_update_policy(unsigned int cpu)
2237 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2238 struct cpufreq_policy new_policy;
2244 down_write(&policy->rwsem);
2246 pr_debug("updating policy for CPU %u\n", cpu);
2247 memcpy(&new_policy, policy, sizeof(*policy));
2248 new_policy.min = policy->user_policy.min;
2249 new_policy.max = policy->user_policy.max;
2252 * BIOS might change freq behind our back
2253 * -> ask driver for current freq and notify governors about a change
2255 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2256 new_policy.cur = cpufreq_driver->get(cpu);
2257 if (WARN_ON(!new_policy.cur)) {
2263 pr_debug("Driver did not initialize current freq\n");
2264 policy->cur = new_policy.cur;
2266 if (policy->cur != new_policy.cur && has_target())
2267 cpufreq_out_of_sync(policy, new_policy.cur);
2271 ret = cpufreq_set_policy(policy, &new_policy);
2274 up_write(&policy->rwsem);
2276 cpufreq_cpu_put(policy);
2279 EXPORT_SYMBOL(cpufreq_update_policy);
2281 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2282 unsigned long action, void *hcpu)
2284 unsigned int cpu = (unsigned long)hcpu;
2286 switch (action & ~CPU_TASKS_FROZEN) {
2288 cpufreq_online(cpu);
2291 case CPU_DOWN_PREPARE:
2292 cpufreq_offline_prepare(cpu);
2296 cpufreq_offline_finish(cpu);
2299 case CPU_DOWN_FAILED:
2300 cpufreq_online(cpu);
2306 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2307 .notifier_call = cpufreq_cpu_callback,
2310 /*********************************************************************
2312 *********************************************************************/
2313 static int cpufreq_boost_set_sw(int state)
2315 struct cpufreq_frequency_table *freq_table;
2316 struct cpufreq_policy *policy;
2319 for_each_active_policy(policy) {
2320 freq_table = cpufreq_frequency_get_table(policy->cpu);
2322 ret = cpufreq_frequency_table_cpuinfo(policy,
2325 pr_err("%s: Policy frequency update failed\n",
2329 policy->user_policy.max = policy->max;
2330 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2337 int cpufreq_boost_trigger_state(int state)
2339 unsigned long flags;
2342 if (cpufreq_driver->boost_enabled == state)
2345 write_lock_irqsave(&cpufreq_driver_lock, flags);
2346 cpufreq_driver->boost_enabled = state;
2347 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2349 ret = cpufreq_driver->set_boost(state);
2351 write_lock_irqsave(&cpufreq_driver_lock, flags);
2352 cpufreq_driver->boost_enabled = !state;
2353 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2355 pr_err("%s: Cannot %s BOOST\n",
2356 __func__, state ? "enable" : "disable");
2362 int cpufreq_boost_supported(void)
2364 if (likely(cpufreq_driver))
2365 return cpufreq_driver->boost_supported;
2369 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2371 static int create_boost_sysfs_file(void)
2375 if (!cpufreq_boost_supported())
2379 * Check if driver provides function to enable boost -
2380 * if not, use cpufreq_boost_set_sw as default
2382 if (!cpufreq_driver->set_boost)
2383 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2385 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2387 pr_err("%s: cannot register global BOOST sysfs file\n",
2393 static void remove_boost_sysfs_file(void)
2395 if (cpufreq_boost_supported())
2396 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2399 int cpufreq_enable_boost_support(void)
2401 if (!cpufreq_driver)
2404 if (cpufreq_boost_supported())
2407 cpufreq_driver->boost_supported = true;
2409 /* This will get removed on driver unregister */
2410 return create_boost_sysfs_file();
2412 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2414 int cpufreq_boost_enabled(void)
2416 return cpufreq_driver->boost_enabled;
2418 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2420 /*********************************************************************
2421 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2422 *********************************************************************/
2425 * cpufreq_register_driver - register a CPU Frequency driver
2426 * @driver_data: A struct cpufreq_driver containing the values#
2427 * submitted by the CPU Frequency driver.
2429 * Registers a CPU Frequency driver to this core code. This code
2430 * returns zero on success, -EBUSY when another driver got here first
2431 * (and isn't unregistered in the meantime).
2434 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2436 unsigned long flags;
2439 if (cpufreq_disabled())
2442 if (!driver_data || !driver_data->verify || !driver_data->init ||
2443 !(driver_data->setpolicy || driver_data->target_index ||
2444 driver_data->target) ||
2445 (driver_data->setpolicy && (driver_data->target_index ||
2446 driver_data->target)) ||
2447 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2450 pr_debug("trying to register driver %s\n", driver_data->name);
2452 /* Protect against concurrent CPU online/offline. */
2455 write_lock_irqsave(&cpufreq_driver_lock, flags);
2456 if (cpufreq_driver) {
2457 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2461 cpufreq_driver = driver_data;
2462 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2464 if (driver_data->setpolicy)
2465 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2467 ret = create_boost_sysfs_file();
2469 goto err_null_driver;
2471 ret = subsys_interface_register(&cpufreq_interface);
2473 goto err_boost_unreg;
2475 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2476 list_empty(&cpufreq_policy_list)) {
2477 /* if all ->init() calls failed, unregister */
2478 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2483 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2484 pr_debug("driver %s up and running\n", driver_data->name);
2491 subsys_interface_unregister(&cpufreq_interface);
2493 remove_boost_sysfs_file();
2495 write_lock_irqsave(&cpufreq_driver_lock, flags);
2496 cpufreq_driver = NULL;
2497 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2500 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2503 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2505 * Unregister the current CPUFreq driver. Only call this if you have
2506 * the right to do so, i.e. if you have succeeded in initialising before!
2507 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2508 * currently not initialised.
2510 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2512 unsigned long flags;
2514 if (!cpufreq_driver || (driver != cpufreq_driver))
2517 pr_debug("unregistering driver %s\n", driver->name);
2519 /* Protect against concurrent cpu hotplug */
2521 subsys_interface_unregister(&cpufreq_interface);
2522 remove_boost_sysfs_file();
2523 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2525 write_lock_irqsave(&cpufreq_driver_lock, flags);
2527 cpufreq_driver = NULL;
2529 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2534 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2537 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2538 * or mutexes when secondary CPUs are halted.
2540 static struct syscore_ops cpufreq_syscore_ops = {
2541 .shutdown = cpufreq_suspend,
2544 struct kobject *cpufreq_global_kobject;
2545 EXPORT_SYMBOL(cpufreq_global_kobject);
2547 static int __init cpufreq_core_init(void)
2549 if (cpufreq_disabled())
2552 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2553 BUG_ON(!cpufreq_global_kobject);
2555 register_syscore_ops(&cpufreq_syscore_ops);
2559 core_initcall(cpufreq_core_init);