2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
34 static LIST_HEAD(cpufreq_policy_list);
36 static inline bool policy_is_inactive(struct cpufreq_policy *policy)
38 return cpumask_empty(policy->cpus);
41 /* Macros to iterate over CPU policies */
42 #define for_each_suitable_policy(__policy, __active) \
43 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
44 if ((__active) == !policy_is_inactive(__policy))
46 #define for_each_active_policy(__policy) \
47 for_each_suitable_policy(__policy, true)
48 #define for_each_inactive_policy(__policy) \
49 for_each_suitable_policy(__policy, false)
51 #define for_each_policy(__policy) \
52 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
54 /* Iterate over governors */
55 static LIST_HEAD(cpufreq_governor_list);
56 #define for_each_governor(__governor) \
57 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
60 * The "cpufreq driver" - the arch- or hardware-dependent low
61 * level driver of CPUFreq support, and its spinlock. This lock
62 * also protects the cpufreq_cpu_data array.
64 static struct cpufreq_driver *cpufreq_driver;
65 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
66 static DEFINE_RWLOCK(cpufreq_driver_lock);
68 /* Flag to suspend/resume CPUFreq governors */
69 static bool cpufreq_suspended;
71 static inline bool has_target(void)
73 return cpufreq_driver->target_index || cpufreq_driver->target;
76 /* internal prototypes */
77 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
78 static int cpufreq_init_governor(struct cpufreq_policy *policy);
79 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
80 static int cpufreq_start_governor(struct cpufreq_policy *policy);
81 static void cpufreq_stop_governor(struct cpufreq_policy *policy);
82 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
85 * Two notifier lists: the "policy" list is involved in the
86 * validation process for a new CPU frequency policy; the
87 * "transition" list for kernel code that needs to handle
88 * changes to devices when the CPU clock speed changes.
89 * The mutex locks both lists.
91 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
92 static struct srcu_notifier_head cpufreq_transition_notifier_list;
94 static bool init_cpufreq_transition_notifier_list_called;
95 static int __init init_cpufreq_transition_notifier_list(void)
97 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
98 init_cpufreq_transition_notifier_list_called = true;
101 pure_initcall(init_cpufreq_transition_notifier_list);
103 static int off __read_mostly;
104 static int cpufreq_disabled(void)
108 void disable_cpufreq(void)
112 static DEFINE_MUTEX(cpufreq_governor_mutex);
114 bool have_governor_per_policy(void)
116 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
118 EXPORT_SYMBOL_GPL(have_governor_per_policy);
120 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
122 if (have_governor_per_policy())
123 return &policy->kobj;
125 return cpufreq_global_kobject;
127 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
129 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
135 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
137 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
138 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
139 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
140 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
141 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
142 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
144 idle_time = cur_wall_time - busy_time;
146 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
148 return div_u64(idle_time, NSEC_PER_USEC);
151 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
153 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
155 if (idle_time == -1ULL)
156 return get_cpu_idle_time_jiffy(cpu, wall);
158 idle_time += get_cpu_iowait_time_us(cpu, wall);
162 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
165 * This is a generic cpufreq init() routine which can be used by cpufreq
166 * drivers of SMP systems. It will do following:
167 * - validate & show freq table passed
168 * - set policies transition latency
169 * - policy->cpus with all possible CPUs
171 int cpufreq_generic_init(struct cpufreq_policy *policy,
172 struct cpufreq_frequency_table *table,
173 unsigned int transition_latency)
177 ret = cpufreq_table_validate_and_show(policy, table);
179 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
183 policy->cpuinfo.transition_latency = transition_latency;
186 * The driver only supports the SMP configuration where all processors
187 * share the clock and voltage and clock.
189 cpumask_setall(policy->cpus);
193 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
197 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
199 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
201 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
203 unsigned int cpufreq_generic_get(unsigned int cpu)
205 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
207 if (!policy || IS_ERR(policy->clk)) {
208 pr_err("%s: No %s associated to cpu: %d\n",
209 __func__, policy ? "clk" : "policy", cpu);
213 return clk_get_rate(policy->clk) / 1000;
215 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
218 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
220 * @cpu: cpu to find policy for.
222 * This returns policy for 'cpu', returns NULL if it doesn't exist.
223 * It also increments the kobject reference count to mark it busy and so would
224 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
225 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
226 * freed as that depends on the kobj count.
228 * Return: A valid policy on success, otherwise NULL on failure.
230 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
232 struct cpufreq_policy *policy = NULL;
235 if (WARN_ON(cpu >= nr_cpu_ids))
238 /* get the cpufreq driver */
239 read_lock_irqsave(&cpufreq_driver_lock, flags);
241 if (cpufreq_driver) {
243 policy = cpufreq_cpu_get_raw(cpu);
245 kobject_get(&policy->kobj);
248 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
252 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
255 * cpufreq_cpu_put: Decrements the usage count of a policy
257 * @policy: policy earlier returned by cpufreq_cpu_get().
259 * This decrements the kobject reference count incremented earlier by calling
262 void cpufreq_cpu_put(struct cpufreq_policy *policy)
264 kobject_put(&policy->kobj);
266 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
268 /*********************************************************************
269 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
270 *********************************************************************/
273 * adjust_jiffies - adjust the system "loops_per_jiffy"
275 * This function alters the system "loops_per_jiffy" for the clock
276 * speed change. Note that loops_per_jiffy cannot be updated on SMP
277 * systems as each CPU might be scaled differently. So, use the arch
278 * per-CPU loops_per_jiffy value wherever possible.
280 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
283 static unsigned long l_p_j_ref;
284 static unsigned int l_p_j_ref_freq;
286 if (ci->flags & CPUFREQ_CONST_LOOPS)
289 if (!l_p_j_ref_freq) {
290 l_p_j_ref = loops_per_jiffy;
291 l_p_j_ref_freq = ci->old;
292 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
293 l_p_j_ref, l_p_j_ref_freq);
295 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
296 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
298 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
299 loops_per_jiffy, ci->new);
304 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
305 struct cpufreq_freqs *freqs, unsigned int state)
307 BUG_ON(irqs_disabled());
309 if (cpufreq_disabled())
312 freqs->flags = cpufreq_driver->flags;
313 pr_debug("notification %u of frequency transition to %u kHz\n",
318 case CPUFREQ_PRECHANGE:
319 /* detect if the driver reported a value as "old frequency"
320 * which is not equal to what the cpufreq core thinks is
323 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
324 if ((policy) && (policy->cpu == freqs->cpu) &&
325 (policy->cur) && (policy->cur != freqs->old)) {
326 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
327 freqs->old, policy->cur);
328 freqs->old = policy->cur;
331 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
332 CPUFREQ_PRECHANGE, freqs);
333 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
336 case CPUFREQ_POSTCHANGE:
337 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
338 pr_debug("FREQ: %lu - CPU: %lu\n",
339 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
340 trace_cpu_frequency(freqs->new, freqs->cpu);
341 cpufreq_stats_record_transition(policy, freqs->new);
342 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
343 CPUFREQ_POSTCHANGE, freqs);
344 if (likely(policy) && likely(policy->cpu == freqs->cpu))
345 policy->cur = freqs->new;
351 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
352 * on frequency transition.
354 * This function calls the transition notifiers and the "adjust_jiffies"
355 * function. It is called twice on all CPU frequency changes that have
358 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
359 struct cpufreq_freqs *freqs, unsigned int state)
361 for_each_cpu(freqs->cpu, policy->cpus)
362 __cpufreq_notify_transition(policy, freqs, state);
365 /* Do post notifications when there are chances that transition has failed */
366 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
367 struct cpufreq_freqs *freqs, int transition_failed)
369 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
370 if (!transition_failed)
373 swap(freqs->old, freqs->new);
374 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
375 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
378 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
379 struct cpufreq_freqs *freqs)
383 * Catch double invocations of _begin() which lead to self-deadlock.
384 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
385 * doesn't invoke _begin() on their behalf, and hence the chances of
386 * double invocations are very low. Moreover, there are scenarios
387 * where these checks can emit false-positive warnings in these
388 * drivers; so we avoid that by skipping them altogether.
390 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
391 && current == policy->transition_task);
394 wait_event(policy->transition_wait, !policy->transition_ongoing);
396 spin_lock(&policy->transition_lock);
398 if (unlikely(policy->transition_ongoing)) {
399 spin_unlock(&policy->transition_lock);
403 policy->transition_ongoing = true;
404 policy->transition_task = current;
406 spin_unlock(&policy->transition_lock);
408 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
410 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
412 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
413 struct cpufreq_freqs *freqs, int transition_failed)
415 if (unlikely(WARN_ON(!policy->transition_ongoing)))
418 cpufreq_notify_post_transition(policy, freqs, transition_failed);
420 policy->transition_ongoing = false;
421 policy->transition_task = NULL;
423 wake_up(&policy->transition_wait);
425 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
428 * Fast frequency switching status count. Positive means "enabled", negative
429 * means "disabled" and 0 means "not decided yet".
431 static int cpufreq_fast_switch_count;
432 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
434 static void cpufreq_list_transition_notifiers(void)
436 struct notifier_block *nb;
438 pr_info("Registered transition notifiers:\n");
440 mutex_lock(&cpufreq_transition_notifier_list.mutex);
442 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
443 pr_info("%pF\n", nb->notifier_call);
445 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
449 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
450 * @policy: cpufreq policy to enable fast frequency switching for.
452 * Try to enable fast frequency switching for @policy.
454 * The attempt will fail if there is at least one transition notifier registered
455 * at this point, as fast frequency switching is quite fundamentally at odds
456 * with transition notifiers. Thus if successful, it will make registration of
457 * transition notifiers fail going forward.
459 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
461 lockdep_assert_held(&policy->rwsem);
463 if (!policy->fast_switch_possible)
466 mutex_lock(&cpufreq_fast_switch_lock);
467 if (cpufreq_fast_switch_count >= 0) {
468 cpufreq_fast_switch_count++;
469 policy->fast_switch_enabled = true;
471 pr_warn("CPU%u: Fast frequency switching not enabled\n",
473 cpufreq_list_transition_notifiers();
475 mutex_unlock(&cpufreq_fast_switch_lock);
477 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
480 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
481 * @policy: cpufreq policy to disable fast frequency switching for.
483 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
485 mutex_lock(&cpufreq_fast_switch_lock);
486 if (policy->fast_switch_enabled) {
487 policy->fast_switch_enabled = false;
488 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
489 cpufreq_fast_switch_count--;
491 mutex_unlock(&cpufreq_fast_switch_lock);
493 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
496 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
498 * @target_freq: target frequency to resolve.
500 * The target to driver frequency mapping is cached in the policy.
502 * Return: Lowest driver-supported frequency greater than or equal to the
503 * given target_freq, subject to policy (min/max) and driver limitations.
505 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
506 unsigned int target_freq)
508 target_freq = clamp_val(target_freq, policy->min, policy->max);
509 policy->cached_target_freq = target_freq;
511 if (cpufreq_driver->target_index) {
514 idx = cpufreq_frequency_table_target(policy, target_freq,
516 policy->cached_resolved_idx = idx;
517 return policy->freq_table[idx].frequency;
520 if (cpufreq_driver->resolve_freq)
521 return cpufreq_driver->resolve_freq(policy, target_freq);
525 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
527 /*********************************************************************
529 *********************************************************************/
530 static ssize_t show_boost(struct kobject *kobj,
531 struct kobj_attribute *attr, char *buf)
533 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
536 static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
537 const char *buf, size_t count)
541 ret = sscanf(buf, "%d", &enable);
542 if (ret != 1 || enable < 0 || enable > 1)
545 if (cpufreq_boost_trigger_state(enable)) {
546 pr_err("%s: Cannot %s BOOST!\n",
547 __func__, enable ? "enable" : "disable");
551 pr_debug("%s: cpufreq BOOST %s\n",
552 __func__, enable ? "enabled" : "disabled");
556 define_one_global_rw(boost);
558 static struct cpufreq_governor *find_governor(const char *str_governor)
560 struct cpufreq_governor *t;
563 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
570 * cpufreq_parse_governor - parse a governor string
572 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
573 struct cpufreq_governor **governor)
577 if (cpufreq_driver->setpolicy) {
578 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
579 *policy = CPUFREQ_POLICY_PERFORMANCE;
581 } else if (!strncasecmp(str_governor, "powersave",
583 *policy = CPUFREQ_POLICY_POWERSAVE;
587 struct cpufreq_governor *t;
589 mutex_lock(&cpufreq_governor_mutex);
591 t = find_governor(str_governor);
596 mutex_unlock(&cpufreq_governor_mutex);
597 ret = request_module("cpufreq_%s", str_governor);
598 mutex_lock(&cpufreq_governor_mutex);
601 t = find_governor(str_governor);
609 mutex_unlock(&cpufreq_governor_mutex);
615 * cpufreq_per_cpu_attr_read() / show_##file_name() -
616 * print out cpufreq information
618 * Write out information from cpufreq_driver->policy[cpu]; object must be
622 #define show_one(file_name, object) \
623 static ssize_t show_##file_name \
624 (struct cpufreq_policy *policy, char *buf) \
626 return sprintf(buf, "%u\n", policy->object); \
629 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
630 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
631 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
632 show_one(scaling_min_freq, min);
633 show_one(scaling_max_freq, max);
635 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
639 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
640 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
642 ret = sprintf(buf, "%u\n", policy->cur);
646 static int cpufreq_set_policy(struct cpufreq_policy *policy,
647 struct cpufreq_policy *new_policy);
650 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
652 #define store_one(file_name, object) \
653 static ssize_t store_##file_name \
654 (struct cpufreq_policy *policy, const char *buf, size_t count) \
657 struct cpufreq_policy new_policy; \
659 memcpy(&new_policy, policy, sizeof(*policy)); \
660 new_policy.min = policy->user_policy.min; \
661 new_policy.max = policy->user_policy.max; \
663 ret = sscanf(buf, "%u", &new_policy.object); \
667 temp = new_policy.object; \
668 ret = cpufreq_set_policy(policy, &new_policy); \
670 policy->user_policy.object = temp; \
672 return ret ? ret : count; \
675 store_one(scaling_min_freq, min);
676 store_one(scaling_max_freq, max);
679 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
681 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
684 unsigned int cur_freq = __cpufreq_get(policy);
687 return sprintf(buf, "%u\n", cur_freq);
689 return sprintf(buf, "<unknown>\n");
693 * show_scaling_governor - show the current policy for the specified CPU
695 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
697 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
698 return sprintf(buf, "powersave\n");
699 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
700 return sprintf(buf, "performance\n");
701 else if (policy->governor)
702 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
703 policy->governor->name);
708 * store_scaling_governor - store policy for the specified CPU
710 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
711 const char *buf, size_t count)
714 char str_governor[16];
715 struct cpufreq_policy new_policy;
717 memcpy(&new_policy, policy, sizeof(*policy));
719 ret = sscanf(buf, "%15s", str_governor);
723 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
724 &new_policy.governor))
727 ret = cpufreq_set_policy(policy, &new_policy);
728 return ret ? ret : count;
732 * show_scaling_driver - show the cpufreq driver currently loaded
734 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
736 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
740 * show_scaling_available_governors - show the available CPUfreq governors
742 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
746 struct cpufreq_governor *t;
749 i += sprintf(buf, "performance powersave");
753 for_each_governor(t) {
754 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
755 - (CPUFREQ_NAME_LEN + 2)))
757 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
760 i += sprintf(&buf[i], "\n");
764 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
769 for_each_cpu(cpu, mask) {
771 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
772 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
773 if (i >= (PAGE_SIZE - 5))
776 i += sprintf(&buf[i], "\n");
779 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
782 * show_related_cpus - show the CPUs affected by each transition even if
783 * hw coordination is in use
785 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
787 return cpufreq_show_cpus(policy->related_cpus, buf);
791 * show_affected_cpus - show the CPUs affected by each transition
793 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
795 return cpufreq_show_cpus(policy->cpus, buf);
798 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
799 const char *buf, size_t count)
801 unsigned int freq = 0;
804 if (!policy->governor || !policy->governor->store_setspeed)
807 ret = sscanf(buf, "%u", &freq);
811 policy->governor->store_setspeed(policy, freq);
816 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
818 if (!policy->governor || !policy->governor->show_setspeed)
819 return sprintf(buf, "<unsupported>\n");
821 return policy->governor->show_setspeed(policy, buf);
825 * show_bios_limit - show the current cpufreq HW/BIOS limitation
827 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
831 if (cpufreq_driver->bios_limit) {
832 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
834 return sprintf(buf, "%u\n", limit);
836 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
839 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
840 cpufreq_freq_attr_ro(cpuinfo_min_freq);
841 cpufreq_freq_attr_ro(cpuinfo_max_freq);
842 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
843 cpufreq_freq_attr_ro(scaling_available_governors);
844 cpufreq_freq_attr_ro(scaling_driver);
845 cpufreq_freq_attr_ro(scaling_cur_freq);
846 cpufreq_freq_attr_ro(bios_limit);
847 cpufreq_freq_attr_ro(related_cpus);
848 cpufreq_freq_attr_ro(affected_cpus);
849 cpufreq_freq_attr_rw(scaling_min_freq);
850 cpufreq_freq_attr_rw(scaling_max_freq);
851 cpufreq_freq_attr_rw(scaling_governor);
852 cpufreq_freq_attr_rw(scaling_setspeed);
854 static struct attribute *default_attrs[] = {
855 &cpuinfo_min_freq.attr,
856 &cpuinfo_max_freq.attr,
857 &cpuinfo_transition_latency.attr,
858 &scaling_min_freq.attr,
859 &scaling_max_freq.attr,
862 &scaling_governor.attr,
863 &scaling_driver.attr,
864 &scaling_available_governors.attr,
865 &scaling_setspeed.attr,
869 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
870 #define to_attr(a) container_of(a, struct freq_attr, attr)
872 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
874 struct cpufreq_policy *policy = to_policy(kobj);
875 struct freq_attr *fattr = to_attr(attr);
881 down_read(&policy->rwsem);
882 ret = fattr->show(policy, buf);
883 up_read(&policy->rwsem);
888 static ssize_t store(struct kobject *kobj, struct attribute *attr,
889 const char *buf, size_t count)
891 struct cpufreq_policy *policy = to_policy(kobj);
892 struct freq_attr *fattr = to_attr(attr);
893 ssize_t ret = -EINVAL;
900 if (cpu_online(policy->cpu)) {
901 down_write(&policy->rwsem);
902 ret = fattr->store(policy, buf, count);
903 up_write(&policy->rwsem);
911 static void cpufreq_sysfs_release(struct kobject *kobj)
913 struct cpufreq_policy *policy = to_policy(kobj);
914 pr_debug("last reference is dropped\n");
915 complete(&policy->kobj_unregister);
918 static const struct sysfs_ops sysfs_ops = {
923 static struct kobj_type ktype_cpufreq = {
924 .sysfs_ops = &sysfs_ops,
925 .default_attrs = default_attrs,
926 .release = cpufreq_sysfs_release,
929 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
931 struct device *dev = get_cpu_device(cpu);
936 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
939 dev_dbg(dev, "%s: Adding symlink\n", __func__);
940 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
941 dev_err(dev, "cpufreq symlink creation failed\n");
944 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
947 dev_dbg(dev, "%s: Removing symlink\n", __func__);
948 sysfs_remove_link(&dev->kobj, "cpufreq");
951 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
953 struct freq_attr **drv_attr;
956 /* set up files for this cpu device */
957 drv_attr = cpufreq_driver->attr;
958 while (drv_attr && *drv_attr) {
959 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
964 if (cpufreq_driver->get) {
965 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
970 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
974 if (cpufreq_driver->bios_limit) {
975 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
983 __weak struct cpufreq_governor *cpufreq_default_governor(void)
988 static int cpufreq_init_policy(struct cpufreq_policy *policy)
990 struct cpufreq_governor *gov = NULL;
991 struct cpufreq_policy new_policy;
993 memcpy(&new_policy, policy, sizeof(*policy));
995 /* Update governor of new_policy to the governor used before hotplug */
996 gov = find_governor(policy->last_governor);
998 pr_debug("Restoring governor %s for cpu %d\n",
999 policy->governor->name, policy->cpu);
1001 gov = cpufreq_default_governor();
1006 new_policy.governor = gov;
1008 /* Use the default policy if there is no last_policy. */
1009 if (cpufreq_driver->setpolicy) {
1010 if (policy->last_policy)
1011 new_policy.policy = policy->last_policy;
1013 cpufreq_parse_governor(gov->name, &new_policy.policy,
1016 /* set default policy */
1017 return cpufreq_set_policy(policy, &new_policy);
1020 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1024 /* Has this CPU been taken care of already? */
1025 if (cpumask_test_cpu(cpu, policy->cpus))
1028 down_write(&policy->rwsem);
1030 cpufreq_stop_governor(policy);
1032 cpumask_set_cpu(cpu, policy->cpus);
1035 ret = cpufreq_start_governor(policy);
1037 pr_err("%s: Failed to start governor\n", __func__);
1039 up_write(&policy->rwsem);
1043 static void handle_update(struct work_struct *work)
1045 struct cpufreq_policy *policy =
1046 container_of(work, struct cpufreq_policy, update);
1047 unsigned int cpu = policy->cpu;
1048 pr_debug("handle_update for cpu %u called\n", cpu);
1049 cpufreq_update_policy(cpu);
1052 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1054 struct cpufreq_policy *policy;
1057 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1061 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1062 goto err_free_policy;
1064 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1065 goto err_free_cpumask;
1067 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1068 goto err_free_rcpumask;
1070 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1071 cpufreq_global_kobject, "policy%u", cpu);
1073 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1074 kobject_put(&policy->kobj);
1075 goto err_free_real_cpus;
1078 INIT_LIST_HEAD(&policy->policy_list);
1079 init_rwsem(&policy->rwsem);
1080 spin_lock_init(&policy->transition_lock);
1081 init_waitqueue_head(&policy->transition_wait);
1082 init_completion(&policy->kobj_unregister);
1083 INIT_WORK(&policy->update, handle_update);
1089 free_cpumask_var(policy->real_cpus);
1091 free_cpumask_var(policy->related_cpus);
1093 free_cpumask_var(policy->cpus);
1100 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1102 struct kobject *kobj;
1103 struct completion *cmp;
1106 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1107 CPUFREQ_REMOVE_POLICY, policy);
1109 down_write(&policy->rwsem);
1110 cpufreq_stats_free_table(policy);
1111 kobj = &policy->kobj;
1112 cmp = &policy->kobj_unregister;
1113 up_write(&policy->rwsem);
1117 * We need to make sure that the underlying kobj is
1118 * actually not referenced anymore by anybody before we
1119 * proceed with unloading.
1121 pr_debug("waiting for dropping of refcount\n");
1122 wait_for_completion(cmp);
1123 pr_debug("wait complete\n");
1126 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1128 unsigned long flags;
1131 /* Remove policy from list */
1132 write_lock_irqsave(&cpufreq_driver_lock, flags);
1133 list_del(&policy->policy_list);
1135 for_each_cpu(cpu, policy->related_cpus)
1136 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1137 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1139 cpufreq_policy_put_kobj(policy, notify);
1140 free_cpumask_var(policy->real_cpus);
1141 free_cpumask_var(policy->related_cpus);
1142 free_cpumask_var(policy->cpus);
1146 static int cpufreq_online(unsigned int cpu)
1148 struct cpufreq_policy *policy;
1150 unsigned long flags;
1154 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1156 /* Check if this CPU already has a policy to manage it */
1157 policy = per_cpu(cpufreq_cpu_data, cpu);
1159 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1160 if (!policy_is_inactive(policy))
1161 return cpufreq_add_policy_cpu(policy, cpu);
1163 /* This is the only online CPU for the policy. Start over. */
1165 down_write(&policy->rwsem);
1167 policy->governor = NULL;
1168 up_write(&policy->rwsem);
1171 policy = cpufreq_policy_alloc(cpu);
1176 cpumask_copy(policy->cpus, cpumask_of(cpu));
1178 /* call driver. From then on the cpufreq must be able
1179 * to accept all calls to ->verify and ->setpolicy for this CPU
1181 ret = cpufreq_driver->init(policy);
1183 pr_debug("initialization failed\n");
1184 goto out_free_policy;
1187 down_write(&policy->rwsem);
1190 /* related_cpus should at least include policy->cpus. */
1191 cpumask_copy(policy->related_cpus, policy->cpus);
1195 * affected cpus must always be the one, which are online. We aren't
1196 * managing offline cpus here.
1198 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1201 policy->user_policy.min = policy->min;
1202 policy->user_policy.max = policy->max;
1204 for_each_cpu(j, policy->related_cpus) {
1205 per_cpu(cpufreq_cpu_data, j) = policy;
1206 add_cpu_dev_symlink(policy, j);
1209 policy->min = policy->user_policy.min;
1210 policy->max = policy->user_policy.max;
1213 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1214 policy->cur = cpufreq_driver->get(policy->cpu);
1216 pr_err("%s: ->get() failed\n", __func__);
1217 goto out_exit_policy;
1222 * Sometimes boot loaders set CPU frequency to a value outside of
1223 * frequency table present with cpufreq core. In such cases CPU might be
1224 * unstable if it has to run on that frequency for long duration of time
1225 * and so its better to set it to a frequency which is specified in
1226 * freq-table. This also makes cpufreq stats inconsistent as
1227 * cpufreq-stats would fail to register because current frequency of CPU
1228 * isn't found in freq-table.
1230 * Because we don't want this change to effect boot process badly, we go
1231 * for the next freq which is >= policy->cur ('cur' must be set by now,
1232 * otherwise we will end up setting freq to lowest of the table as 'cur'
1233 * is initialized to zero).
1235 * We are passing target-freq as "policy->cur - 1" otherwise
1236 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1237 * equal to target-freq.
1239 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1241 /* Are we running at unknown frequency ? */
1242 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1243 if (ret == -EINVAL) {
1244 /* Warn user and fix it */
1245 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1246 __func__, policy->cpu, policy->cur);
1247 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1248 CPUFREQ_RELATION_L);
1251 * Reaching here after boot in a few seconds may not
1252 * mean that system will remain stable at "unknown"
1253 * frequency for longer duration. Hence, a BUG_ON().
1256 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1257 __func__, policy->cpu, policy->cur);
1262 ret = cpufreq_add_dev_interface(policy);
1264 goto out_exit_policy;
1266 cpufreq_stats_create_table(policy);
1267 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1268 CPUFREQ_CREATE_POLICY, policy);
1270 write_lock_irqsave(&cpufreq_driver_lock, flags);
1271 list_add(&policy->policy_list, &cpufreq_policy_list);
1272 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1275 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1276 CPUFREQ_START, policy);
1278 ret = cpufreq_init_policy(policy);
1280 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1281 __func__, cpu, ret);
1282 /* cpufreq_policy_free() will notify based on this */
1284 goto out_exit_policy;
1287 up_write(&policy->rwsem);
1289 kobject_uevent(&policy->kobj, KOBJ_ADD);
1291 /* Callback for handling stuff after policy is ready */
1292 if (cpufreq_driver->ready)
1293 cpufreq_driver->ready(policy);
1295 pr_debug("initialization complete\n");
1300 for_each_cpu(j, policy->real_cpus)
1301 remove_cpu_dev_symlink(policy, get_cpu_device(j));
1303 up_write(&policy->rwsem);
1305 if (cpufreq_driver->exit)
1306 cpufreq_driver->exit(policy);
1309 cpufreq_policy_free(policy, !new_policy);
1314 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1316 * @sif: Subsystem interface structure pointer (not used)
1318 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1320 struct cpufreq_policy *policy;
1321 unsigned cpu = dev->id;
1324 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1326 if (cpu_online(cpu)) {
1327 ret = cpufreq_online(cpu);
1332 /* Create sysfs link on CPU registration */
1333 policy = per_cpu(cpufreq_cpu_data, cpu);
1335 add_cpu_dev_symlink(policy, cpu);
1340 static int cpufreq_offline(unsigned int cpu)
1342 struct cpufreq_policy *policy;
1345 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1347 policy = cpufreq_cpu_get_raw(cpu);
1349 pr_debug("%s: No cpu_data found\n", __func__);
1353 down_write(&policy->rwsem);
1355 cpufreq_stop_governor(policy);
1357 cpumask_clear_cpu(cpu, policy->cpus);
1359 if (policy_is_inactive(policy)) {
1361 strncpy(policy->last_governor, policy->governor->name,
1364 policy->last_policy = policy->policy;
1365 } else if (cpu == policy->cpu) {
1366 /* Nominate new CPU */
1367 policy->cpu = cpumask_any(policy->cpus);
1370 /* Start governor again for active policy */
1371 if (!policy_is_inactive(policy)) {
1373 ret = cpufreq_start_governor(policy);
1375 pr_err("%s: Failed to start governor\n", __func__);
1381 if (cpufreq_driver->stop_cpu)
1382 cpufreq_driver->stop_cpu(policy);
1385 cpufreq_exit_governor(policy);
1388 * Perform the ->exit() even during light-weight tear-down,
1389 * since this is a core component, and is essential for the
1390 * subsequent light-weight ->init() to succeed.
1392 if (cpufreq_driver->exit) {
1393 cpufreq_driver->exit(policy);
1394 policy->freq_table = NULL;
1398 up_write(&policy->rwsem);
1403 * cpufreq_remove_dev - remove a CPU device
1405 * Removes the cpufreq interface for a CPU device.
1407 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1409 unsigned int cpu = dev->id;
1410 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1415 if (cpu_online(cpu))
1416 cpufreq_offline(cpu);
1418 cpumask_clear_cpu(cpu, policy->real_cpus);
1419 remove_cpu_dev_symlink(policy, dev);
1421 if (cpumask_empty(policy->real_cpus))
1422 cpufreq_policy_free(policy, true);
1426 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1428 * @policy: policy managing CPUs
1429 * @new_freq: CPU frequency the CPU actually runs at
1431 * We adjust to current frequency first, and need to clean up later.
1432 * So either call to cpufreq_update_policy() or schedule handle_update()).
1434 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1435 unsigned int new_freq)
1437 struct cpufreq_freqs freqs;
1439 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1440 policy->cur, new_freq);
1442 freqs.old = policy->cur;
1443 freqs.new = new_freq;
1445 cpufreq_freq_transition_begin(policy, &freqs);
1446 cpufreq_freq_transition_end(policy, &freqs, 0);
1450 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1453 * This is the last known freq, without actually getting it from the driver.
1454 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1456 unsigned int cpufreq_quick_get(unsigned int cpu)
1458 struct cpufreq_policy *policy;
1459 unsigned int ret_freq = 0;
1460 unsigned long flags;
1462 read_lock_irqsave(&cpufreq_driver_lock, flags);
1464 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1465 ret_freq = cpufreq_driver->get(cpu);
1466 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1470 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
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 (unlikely(policy_is_inactive(policy)) || !cpufreq_driver->get)
1509 ret_freq = cpufreq_driver->get(policy->cpu);
1512 * If fast frequency switching is used with the given policy, the check
1513 * against policy->cur is pointless, so skip it in that case too.
1515 if (policy->fast_switch_enabled)
1518 if (ret_freq && policy->cur &&
1519 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1520 /* verify no discrepancy between actual and
1521 saved value exists */
1522 if (unlikely(ret_freq != policy->cur)) {
1523 cpufreq_out_of_sync(policy, ret_freq);
1524 schedule_work(&policy->update);
1532 * cpufreq_get - get the current CPU frequency (in kHz)
1535 * Get the CPU current (static) CPU frequency
1537 unsigned int cpufreq_get(unsigned int cpu)
1539 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1540 unsigned int ret_freq = 0;
1543 down_read(&policy->rwsem);
1544 ret_freq = __cpufreq_get(policy);
1545 up_read(&policy->rwsem);
1547 cpufreq_cpu_put(policy);
1552 EXPORT_SYMBOL(cpufreq_get);
1554 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1556 unsigned int new_freq;
1558 new_freq = cpufreq_driver->get(policy->cpu);
1563 pr_debug("cpufreq: Driver did not initialize current freq\n");
1564 policy->cur = new_freq;
1565 } else if (policy->cur != new_freq && has_target()) {
1566 cpufreq_out_of_sync(policy, new_freq);
1572 static struct subsys_interface cpufreq_interface = {
1574 .subsys = &cpu_subsys,
1575 .add_dev = cpufreq_add_dev,
1576 .remove_dev = cpufreq_remove_dev,
1580 * In case platform wants some specific frequency to be configured
1583 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1587 if (!policy->suspend_freq) {
1588 pr_debug("%s: suspend_freq not defined\n", __func__);
1592 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1593 policy->suspend_freq);
1595 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1596 CPUFREQ_RELATION_H);
1598 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1599 __func__, policy->suspend_freq, ret);
1603 EXPORT_SYMBOL(cpufreq_generic_suspend);
1606 * cpufreq_suspend() - Suspend CPUFreq governors
1608 * Called during system wide Suspend/Hibernate cycles for suspending governors
1609 * as some platforms can't change frequency after this point in suspend cycle.
1610 * Because some of the devices (like: i2c, regulators, etc) they use for
1611 * changing frequency are suspended quickly after this point.
1613 void cpufreq_suspend(void)
1615 struct cpufreq_policy *policy;
1617 if (!cpufreq_driver)
1620 if (!has_target() && !cpufreq_driver->suspend)
1623 pr_debug("%s: Suspending Governors\n", __func__);
1625 for_each_active_policy(policy) {
1627 down_write(&policy->rwsem);
1628 cpufreq_stop_governor(policy);
1629 up_write(&policy->rwsem);
1632 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1633 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1638 cpufreq_suspended = true;
1642 * cpufreq_resume() - Resume CPUFreq governors
1644 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1645 * are suspended with cpufreq_suspend().
1647 void cpufreq_resume(void)
1649 struct cpufreq_policy *policy;
1652 if (!cpufreq_driver)
1655 if (unlikely(!cpufreq_suspended))
1658 cpufreq_suspended = false;
1660 if (!has_target() && !cpufreq_driver->resume)
1663 pr_debug("%s: Resuming Governors\n", __func__);
1665 for_each_active_policy(policy) {
1666 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1667 pr_err("%s: Failed to resume driver: %p\n", __func__,
1669 } else if (has_target()) {
1670 down_write(&policy->rwsem);
1671 ret = cpufreq_start_governor(policy);
1672 up_write(&policy->rwsem);
1675 pr_err("%s: Failed to start governor for policy: %p\n",
1682 * cpufreq_get_current_driver - return current driver's name
1684 * Return the name string of the currently loaded cpufreq driver
1687 const char *cpufreq_get_current_driver(void)
1690 return cpufreq_driver->name;
1694 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1697 * cpufreq_get_driver_data - return current driver data
1699 * Return the private data of the currently loaded cpufreq
1700 * driver, or NULL if no cpufreq driver is loaded.
1702 void *cpufreq_get_driver_data(void)
1705 return cpufreq_driver->driver_data;
1709 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1711 /*********************************************************************
1712 * NOTIFIER LISTS INTERFACE *
1713 *********************************************************************/
1716 * cpufreq_register_notifier - register a driver with cpufreq
1717 * @nb: notifier function to register
1718 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1720 * Add a driver to one of two lists: either a list of drivers that
1721 * are notified about clock rate changes (once before and once after
1722 * the transition), or a list of drivers that are notified about
1723 * changes in cpufreq policy.
1725 * This function may sleep, and has the same return conditions as
1726 * blocking_notifier_chain_register.
1728 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1732 if (cpufreq_disabled())
1735 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1738 case CPUFREQ_TRANSITION_NOTIFIER:
1739 mutex_lock(&cpufreq_fast_switch_lock);
1741 if (cpufreq_fast_switch_count > 0) {
1742 mutex_unlock(&cpufreq_fast_switch_lock);
1745 ret = srcu_notifier_chain_register(
1746 &cpufreq_transition_notifier_list, nb);
1748 cpufreq_fast_switch_count--;
1750 mutex_unlock(&cpufreq_fast_switch_lock);
1752 case CPUFREQ_POLICY_NOTIFIER:
1753 ret = blocking_notifier_chain_register(
1754 &cpufreq_policy_notifier_list, nb);
1762 EXPORT_SYMBOL(cpufreq_register_notifier);
1765 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1766 * @nb: notifier block to be unregistered
1767 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1769 * Remove a driver from the CPU frequency notifier list.
1771 * This function may sleep, and has the same return conditions as
1772 * blocking_notifier_chain_unregister.
1774 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1778 if (cpufreq_disabled())
1782 case CPUFREQ_TRANSITION_NOTIFIER:
1783 mutex_lock(&cpufreq_fast_switch_lock);
1785 ret = srcu_notifier_chain_unregister(
1786 &cpufreq_transition_notifier_list, nb);
1787 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1788 cpufreq_fast_switch_count++;
1790 mutex_unlock(&cpufreq_fast_switch_lock);
1792 case CPUFREQ_POLICY_NOTIFIER:
1793 ret = blocking_notifier_chain_unregister(
1794 &cpufreq_policy_notifier_list, nb);
1802 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1805 /*********************************************************************
1807 *********************************************************************/
1810 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1811 * @policy: cpufreq policy to switch the frequency for.
1812 * @target_freq: New frequency to set (may be approximate).
1814 * Carry out a fast frequency switch without sleeping.
1816 * The driver's ->fast_switch() callback invoked by this function must be
1817 * suitable for being called from within RCU-sched read-side critical sections
1818 * and it is expected to select the minimum available frequency greater than or
1819 * equal to @target_freq (CPUFREQ_RELATION_L).
1821 * This function must not be called if policy->fast_switch_enabled is unset.
1823 * Governors calling this function must guarantee that it will never be invoked
1824 * twice in parallel for the same policy and that it will never be called in
1825 * parallel with either ->target() or ->target_index() for the same policy.
1827 * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()
1828 * callback to indicate an error condition, the hardware configuration must be
1831 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1832 unsigned int target_freq)
1834 target_freq = clamp_val(target_freq, policy->min, policy->max);
1836 return cpufreq_driver->fast_switch(policy, target_freq);
1838 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1840 /* Must set freqs->new to intermediate frequency */
1841 static int __target_intermediate(struct cpufreq_policy *policy,
1842 struct cpufreq_freqs *freqs, int index)
1846 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1848 /* We don't need to switch to intermediate freq */
1852 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1853 __func__, policy->cpu, freqs->old, freqs->new);
1855 cpufreq_freq_transition_begin(policy, freqs);
1856 ret = cpufreq_driver->target_intermediate(policy, index);
1857 cpufreq_freq_transition_end(policy, freqs, ret);
1860 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1866 static int __target_index(struct cpufreq_policy *policy, int index)
1868 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1869 unsigned int intermediate_freq = 0;
1870 unsigned int newfreq = policy->freq_table[index].frequency;
1871 int retval = -EINVAL;
1874 if (newfreq == policy->cur)
1877 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1879 /* Handle switching to intermediate frequency */
1880 if (cpufreq_driver->get_intermediate) {
1881 retval = __target_intermediate(policy, &freqs, index);
1885 intermediate_freq = freqs.new;
1886 /* Set old freq to intermediate */
1887 if (intermediate_freq)
1888 freqs.old = freqs.new;
1891 freqs.new = newfreq;
1892 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1893 __func__, policy->cpu, freqs.old, freqs.new);
1895 cpufreq_freq_transition_begin(policy, &freqs);
1898 retval = cpufreq_driver->target_index(policy, index);
1900 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1904 cpufreq_freq_transition_end(policy, &freqs, retval);
1907 * Failed after setting to intermediate freq? Driver should have
1908 * reverted back to initial frequency and so should we. Check
1909 * here for intermediate_freq instead of get_intermediate, in
1910 * case we haven't switched to intermediate freq at all.
1912 if (unlikely(retval && intermediate_freq)) {
1913 freqs.old = intermediate_freq;
1914 freqs.new = policy->restore_freq;
1915 cpufreq_freq_transition_begin(policy, &freqs);
1916 cpufreq_freq_transition_end(policy, &freqs, 0);
1923 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1924 unsigned int target_freq,
1925 unsigned int relation)
1927 unsigned int old_target_freq = target_freq;
1930 if (cpufreq_disabled())
1933 /* Make sure that target_freq is within supported range */
1934 target_freq = clamp_val(target_freq, policy->min, policy->max);
1936 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1937 policy->cpu, target_freq, relation, old_target_freq);
1940 * This might look like a redundant call as we are checking it again
1941 * after finding index. But it is left intentionally for cases where
1942 * exactly same freq is called again and so we can save on few function
1945 if (target_freq == policy->cur)
1948 /* Save last value to restore later on errors */
1949 policy->restore_freq = policy->cur;
1951 if (cpufreq_driver->target)
1952 return cpufreq_driver->target(policy, target_freq, relation);
1954 if (!cpufreq_driver->target_index)
1957 index = cpufreq_frequency_table_target(policy, target_freq, relation);
1959 return __target_index(policy, index);
1961 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1963 int cpufreq_driver_target(struct cpufreq_policy *policy,
1964 unsigned int target_freq,
1965 unsigned int relation)
1969 down_write(&policy->rwsem);
1971 ret = __cpufreq_driver_target(policy, target_freq, relation);
1973 up_write(&policy->rwsem);
1977 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1979 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1984 static int cpufreq_init_governor(struct cpufreq_policy *policy)
1988 /* Don't start any governor operations if we are entering suspend */
1989 if (cpufreq_suspended)
1992 * Governor might not be initiated here if ACPI _PPC changed
1993 * notification happened, so check it.
1995 if (!policy->governor)
1998 if (policy->governor->max_transition_latency &&
1999 policy->cpuinfo.transition_latency >
2000 policy->governor->max_transition_latency) {
2001 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2004 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2005 policy->governor->name, gov->name);
2006 policy->governor = gov;
2012 if (!try_module_get(policy->governor->owner))
2015 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2017 if (policy->governor->init) {
2018 ret = policy->governor->init(policy);
2020 module_put(policy->governor->owner);
2028 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2030 if (cpufreq_suspended || !policy->governor)
2033 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2035 if (policy->governor->exit)
2036 policy->governor->exit(policy);
2038 module_put(policy->governor->owner);
2041 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2045 if (cpufreq_suspended)
2048 if (!policy->governor)
2051 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2053 if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2054 cpufreq_update_current_freq(policy);
2056 if (policy->governor->start) {
2057 ret = policy->governor->start(policy);
2062 if (policy->governor->limits)
2063 policy->governor->limits(policy);
2068 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2070 if (cpufreq_suspended || !policy->governor)
2073 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2075 if (policy->governor->stop)
2076 policy->governor->stop(policy);
2079 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2081 if (cpufreq_suspended || !policy->governor)
2084 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2086 if (policy->governor->limits)
2087 policy->governor->limits(policy);
2090 int cpufreq_register_governor(struct cpufreq_governor *governor)
2097 if (cpufreq_disabled())
2100 mutex_lock(&cpufreq_governor_mutex);
2103 if (!find_governor(governor->name)) {
2105 list_add(&governor->governor_list, &cpufreq_governor_list);
2108 mutex_unlock(&cpufreq_governor_mutex);
2111 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2113 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2115 struct cpufreq_policy *policy;
2116 unsigned long flags;
2121 if (cpufreq_disabled())
2124 /* clear last_governor for all inactive policies */
2125 read_lock_irqsave(&cpufreq_driver_lock, flags);
2126 for_each_inactive_policy(policy) {
2127 if (!strcmp(policy->last_governor, governor->name)) {
2128 policy->governor = NULL;
2129 strcpy(policy->last_governor, "\0");
2132 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2134 mutex_lock(&cpufreq_governor_mutex);
2135 list_del(&governor->governor_list);
2136 mutex_unlock(&cpufreq_governor_mutex);
2139 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2142 /*********************************************************************
2143 * POLICY INTERFACE *
2144 *********************************************************************/
2147 * cpufreq_get_policy - get the current cpufreq_policy
2148 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2151 * Reads the current cpufreq policy.
2153 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2155 struct cpufreq_policy *cpu_policy;
2159 cpu_policy = cpufreq_cpu_get(cpu);
2163 memcpy(policy, cpu_policy, sizeof(*policy));
2165 cpufreq_cpu_put(cpu_policy);
2168 EXPORT_SYMBOL(cpufreq_get_policy);
2171 * policy : current policy.
2172 * new_policy: policy to be set.
2174 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2175 struct cpufreq_policy *new_policy)
2177 struct cpufreq_governor *old_gov;
2180 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2181 new_policy->cpu, new_policy->min, new_policy->max);
2183 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2186 * This check works well when we store new min/max freq attributes,
2187 * because new_policy is a copy of policy with one field updated.
2189 if (new_policy->min > new_policy->max)
2192 /* verify the cpu speed can be set within this limit */
2193 ret = cpufreq_driver->verify(new_policy);
2197 /* adjust if necessary - all reasons */
2198 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2199 CPUFREQ_ADJUST, new_policy);
2202 * verify the cpu speed can be set within this limit, which might be
2203 * different to the first one
2205 ret = cpufreq_driver->verify(new_policy);
2209 /* notification of the new policy */
2210 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2211 CPUFREQ_NOTIFY, new_policy);
2213 policy->min = new_policy->min;
2214 policy->max = new_policy->max;
2216 policy->cached_target_freq = UINT_MAX;
2218 pr_debug("new min and max freqs are %u - %u kHz\n",
2219 policy->min, policy->max);
2221 if (cpufreq_driver->setpolicy) {
2222 policy->policy = new_policy->policy;
2223 pr_debug("setting range\n");
2224 return cpufreq_driver->setpolicy(new_policy);
2227 if (new_policy->governor == policy->governor) {
2228 pr_debug("cpufreq: governor limits update\n");
2229 cpufreq_governor_limits(policy);
2233 pr_debug("governor switch\n");
2235 /* save old, working values */
2236 old_gov = policy->governor;
2237 /* end old governor */
2239 cpufreq_stop_governor(policy);
2240 cpufreq_exit_governor(policy);
2243 /* start new governor */
2244 policy->governor = new_policy->governor;
2245 ret = cpufreq_init_governor(policy);
2247 ret = cpufreq_start_governor(policy);
2249 pr_debug("cpufreq: governor change\n");
2252 cpufreq_exit_governor(policy);
2255 /* new governor failed, so re-start old one */
2256 pr_debug("starting governor %s failed\n", policy->governor->name);
2258 policy->governor = old_gov;
2259 if (cpufreq_init_governor(policy))
2260 policy->governor = NULL;
2262 cpufreq_start_governor(policy);
2269 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2270 * @cpu: CPU which shall be re-evaluated
2272 * Useful for policy notifiers which have different necessities
2273 * at different times.
2275 int cpufreq_update_policy(unsigned int cpu)
2277 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2278 struct cpufreq_policy new_policy;
2284 down_write(&policy->rwsem);
2286 pr_debug("updating policy for CPU %u\n", cpu);
2287 memcpy(&new_policy, policy, sizeof(*policy));
2288 new_policy.min = policy->user_policy.min;
2289 new_policy.max = policy->user_policy.max;
2292 * BIOS might change freq behind our back
2293 * -> ask driver for current freq and notify governors about a change
2295 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2296 if (cpufreq_suspended) {
2300 new_policy.cur = cpufreq_update_current_freq(policy);
2301 if (WARN_ON(!new_policy.cur)) {
2307 ret = cpufreq_set_policy(policy, &new_policy);
2310 up_write(&policy->rwsem);
2312 cpufreq_cpu_put(policy);
2315 EXPORT_SYMBOL(cpufreq_update_policy);
2317 /*********************************************************************
2319 *********************************************************************/
2320 static int cpufreq_boost_set_sw(int state)
2322 struct cpufreq_policy *policy;
2325 for_each_active_policy(policy) {
2326 if (!policy->freq_table)
2329 ret = cpufreq_frequency_table_cpuinfo(policy,
2330 policy->freq_table);
2332 pr_err("%s: Policy frequency update failed\n",
2337 down_write(&policy->rwsem);
2338 policy->user_policy.max = policy->max;
2339 cpufreq_governor_limits(policy);
2340 up_write(&policy->rwsem);
2346 int cpufreq_boost_trigger_state(int state)
2348 unsigned long flags;
2351 if (cpufreq_driver->boost_enabled == state)
2354 write_lock_irqsave(&cpufreq_driver_lock, flags);
2355 cpufreq_driver->boost_enabled = state;
2356 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2358 ret = cpufreq_driver->set_boost(state);
2360 write_lock_irqsave(&cpufreq_driver_lock, flags);
2361 cpufreq_driver->boost_enabled = !state;
2362 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2364 pr_err("%s: Cannot %s BOOST\n",
2365 __func__, state ? "enable" : "disable");
2371 static bool cpufreq_boost_supported(void)
2373 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2376 static int create_boost_sysfs_file(void)
2380 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2382 pr_err("%s: cannot register global BOOST sysfs file\n",
2388 static void remove_boost_sysfs_file(void)
2390 if (cpufreq_boost_supported())
2391 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2394 int cpufreq_enable_boost_support(void)
2396 if (!cpufreq_driver)
2399 if (cpufreq_boost_supported())
2402 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2404 /* This will get removed on driver unregister */
2405 return create_boost_sysfs_file();
2407 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2409 int cpufreq_boost_enabled(void)
2411 return cpufreq_driver->boost_enabled;
2413 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2415 /*********************************************************************
2416 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2417 *********************************************************************/
2418 static enum cpuhp_state hp_online;
2420 static int cpuhp_cpufreq_online(unsigned int cpu)
2422 cpufreq_online(cpu);
2427 static int cpuhp_cpufreq_offline(unsigned int cpu)
2429 cpufreq_offline(cpu);
2435 * cpufreq_register_driver - register a CPU Frequency driver
2436 * @driver_data: A struct cpufreq_driver containing the values#
2437 * submitted by the CPU Frequency driver.
2439 * Registers a CPU Frequency driver to this core code. This code
2440 * returns zero on success, -EEXIST when another driver got here first
2441 * (and isn't unregistered in the meantime).
2444 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2446 unsigned long flags;
2449 if (cpufreq_disabled())
2453 * The cpufreq core depends heavily on the availability of device
2454 * structure, make sure they are available before proceeding further.
2456 if (!get_cpu_device(0))
2457 return -EPROBE_DEFER;
2459 if (!driver_data || !driver_data->verify || !driver_data->init ||
2460 !(driver_data->setpolicy || driver_data->target_index ||
2461 driver_data->target) ||
2462 (driver_data->setpolicy && (driver_data->target_index ||
2463 driver_data->target)) ||
2464 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2467 pr_debug("trying to register driver %s\n", driver_data->name);
2469 /* Protect against concurrent CPU online/offline. */
2472 write_lock_irqsave(&cpufreq_driver_lock, flags);
2473 if (cpufreq_driver) {
2474 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2478 cpufreq_driver = driver_data;
2479 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2481 if (driver_data->setpolicy)
2482 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2484 if (cpufreq_boost_supported()) {
2485 ret = create_boost_sysfs_file();
2487 goto err_null_driver;
2490 ret = subsys_interface_register(&cpufreq_interface);
2492 goto err_boost_unreg;
2494 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2495 list_empty(&cpufreq_policy_list)) {
2496 /* if all ->init() calls failed, unregister */
2498 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2503 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online",
2504 cpuhp_cpufreq_online,
2505 cpuhp_cpufreq_offline);
2511 pr_debug("driver %s up and running\n", driver_data->name);
2515 subsys_interface_unregister(&cpufreq_interface);
2517 remove_boost_sysfs_file();
2519 write_lock_irqsave(&cpufreq_driver_lock, flags);
2520 cpufreq_driver = NULL;
2521 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2526 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2529 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2531 * Unregister the current CPUFreq driver. Only call this if you have
2532 * the right to do so, i.e. if you have succeeded in initialising before!
2533 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2534 * currently not initialised.
2536 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2538 unsigned long flags;
2540 if (!cpufreq_driver || (driver != cpufreq_driver))
2543 pr_debug("unregistering driver %s\n", driver->name);
2545 /* Protect against concurrent cpu hotplug */
2547 subsys_interface_unregister(&cpufreq_interface);
2548 remove_boost_sysfs_file();
2549 cpuhp_remove_state_nocalls(hp_online);
2551 write_lock_irqsave(&cpufreq_driver_lock, flags);
2553 cpufreq_driver = NULL;
2555 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2560 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2562 struct kobject *cpufreq_global_kobject;
2563 EXPORT_SYMBOL(cpufreq_global_kobject);
2565 static int __init cpufreq_core_init(void)
2567 if (cpufreq_disabled())
2570 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2571 BUG_ON(!cpufreq_global_kobject);
2575 core_initcall(cpufreq_core_init);