1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/drivers/cpufreq/cpufreq.c
5 * Copyright (C) 2001 Russell King
6 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
9 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
10 * Added handling for CPU hotplug
11 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
12 * Fix handling for CPU hotplug -- affected CPUs
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 #include <linux/cpu.h>
18 #include <linux/cpufreq.h>
19 #include <linux/cpu_cooling.h>
20 #include <linux/delay.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/kernel_stat.h>
24 #include <linux/module.h>
25 #include <linux/mutex.h>
26 #include <linux/pm_qos.h>
27 #include <linux/slab.h>
28 #include <linux/suspend.h>
29 #include <linux/syscore_ops.h>
30 #include <linux/tick.h>
31 #include <trace/events/power.h>
33 static LIST_HEAD(cpufreq_policy_list);
35 /* Macros to iterate over CPU policies */
36 #define for_each_suitable_policy(__policy, __active) \
37 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
38 if ((__active) == !policy_is_inactive(__policy))
40 #define for_each_active_policy(__policy) \
41 for_each_suitable_policy(__policy, true)
42 #define for_each_inactive_policy(__policy) \
43 for_each_suitable_policy(__policy, false)
45 /* Iterate over governors */
46 static LIST_HEAD(cpufreq_governor_list);
47 #define for_each_governor(__governor) \
48 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
50 static char default_governor[CPUFREQ_NAME_LEN];
53 * The "cpufreq driver" - the arch- or hardware-dependent low
54 * level driver of CPUFreq support, and its spinlock. This lock
55 * also protects the cpufreq_cpu_data array.
57 static struct cpufreq_driver *cpufreq_driver;
58 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
59 static DEFINE_RWLOCK(cpufreq_driver_lock);
61 static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
62 bool cpufreq_supports_freq_invariance(void)
64 return static_branch_likely(&cpufreq_freq_invariance);
67 /* Flag to suspend/resume CPUFreq governors */
68 static bool cpufreq_suspended;
70 static inline bool has_target(void)
72 return cpufreq_driver->target_index || cpufreq_driver->target;
75 /* internal prototypes */
76 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
77 static int cpufreq_init_governor(struct cpufreq_policy *policy);
78 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
79 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
80 static int cpufreq_set_policy(struct cpufreq_policy *policy,
81 struct cpufreq_governor *new_gov,
82 unsigned int new_pol);
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 SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
94 static int off __read_mostly;
95 static int cpufreq_disabled(void)
99 void disable_cpufreq(void)
103 static DEFINE_MUTEX(cpufreq_governor_mutex);
105 bool have_governor_per_policy(void)
107 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
109 EXPORT_SYMBOL_GPL(have_governor_per_policy);
111 static struct kobject *cpufreq_global_kobject;
113 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
115 if (have_governor_per_policy())
116 return &policy->kobj;
118 return cpufreq_global_kobject;
120 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
122 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
124 struct kernel_cpustat kcpustat;
129 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
131 kcpustat_cpu_fetch(&kcpustat, cpu);
133 busy_time = kcpustat.cpustat[CPUTIME_USER];
134 busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
135 busy_time += kcpustat.cpustat[CPUTIME_IRQ];
136 busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
137 busy_time += kcpustat.cpustat[CPUTIME_STEAL];
138 busy_time += kcpustat.cpustat[CPUTIME_NICE];
140 idle_time = cur_wall_time - busy_time;
142 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
144 return div_u64(idle_time, NSEC_PER_USEC);
147 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
149 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
151 if (idle_time == -1ULL)
152 return get_cpu_idle_time_jiffy(cpu, wall);
154 idle_time += get_cpu_iowait_time_us(cpu, wall);
158 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
161 * This is a generic cpufreq init() routine which can be used by cpufreq
162 * drivers of SMP systems. It will do following:
163 * - validate & show freq table passed
164 * - set policies transition latency
165 * - policy->cpus with all possible CPUs
167 void cpufreq_generic_init(struct cpufreq_policy *policy,
168 struct cpufreq_frequency_table *table,
169 unsigned int transition_latency)
171 policy->freq_table = table;
172 policy->cpuinfo.transition_latency = transition_latency;
175 * The driver only supports the SMP configuration where all processors
176 * share the clock and voltage and clock.
178 cpumask_setall(policy->cpus);
180 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
182 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
184 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
186 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
188 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
190 unsigned int cpufreq_generic_get(unsigned int cpu)
192 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
194 if (!policy || IS_ERR(policy->clk)) {
195 pr_err("%s: No %s associated to cpu: %d\n",
196 __func__, policy ? "clk" : "policy", cpu);
200 return clk_get_rate(policy->clk) / 1000;
202 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
205 * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
206 * @cpu: CPU to find the policy for.
208 * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
209 * the kobject reference counter of that policy. Return a valid policy on
210 * success or NULL on failure.
212 * The policy returned by this function has to be released with the help of
213 * cpufreq_cpu_put() to balance its kobject reference counter properly.
215 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
217 struct cpufreq_policy *policy = NULL;
220 if (WARN_ON(cpu >= nr_cpu_ids))
223 /* get the cpufreq driver */
224 read_lock_irqsave(&cpufreq_driver_lock, flags);
226 if (cpufreq_driver) {
228 policy = cpufreq_cpu_get_raw(cpu);
230 kobject_get(&policy->kobj);
233 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
237 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
240 * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
241 * @policy: cpufreq policy returned by cpufreq_cpu_get().
243 void cpufreq_cpu_put(struct cpufreq_policy *policy)
245 kobject_put(&policy->kobj);
247 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
250 * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
251 * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
253 void cpufreq_cpu_release(struct cpufreq_policy *policy)
255 if (WARN_ON(!policy))
258 lockdep_assert_held(&policy->rwsem);
260 up_write(&policy->rwsem);
262 cpufreq_cpu_put(policy);
266 * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
267 * @cpu: CPU to find the policy for.
269 * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
270 * if the policy returned by it is not NULL, acquire its rwsem for writing.
271 * Return the policy if it is active or release it and return NULL otherwise.
273 * The policy returned by this function has to be released with the help of
274 * cpufreq_cpu_release() in order to release its rwsem and balance its usage
277 struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
279 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
284 down_write(&policy->rwsem);
286 if (policy_is_inactive(policy)) {
287 cpufreq_cpu_release(policy);
294 /*********************************************************************
295 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
296 *********************************************************************/
299 * adjust_jiffies - Adjust the system "loops_per_jiffy".
300 * @val: CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
301 * @ci: Frequency change information.
303 * This function alters the system "loops_per_jiffy" for the clock
304 * speed change. Note that loops_per_jiffy cannot be updated on SMP
305 * systems as each CPU might be scaled differently. So, use the arch
306 * per-CPU loops_per_jiffy value wherever possible.
308 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
311 static unsigned long l_p_j_ref;
312 static unsigned int l_p_j_ref_freq;
314 if (ci->flags & CPUFREQ_CONST_LOOPS)
317 if (!l_p_j_ref_freq) {
318 l_p_j_ref = loops_per_jiffy;
319 l_p_j_ref_freq = ci->old;
320 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
321 l_p_j_ref, l_p_j_ref_freq);
323 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
324 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
326 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
327 loops_per_jiffy, ci->new);
333 * cpufreq_notify_transition - Notify frequency transition and adjust jiffies.
334 * @policy: cpufreq policy to enable fast frequency switching for.
335 * @freqs: contain details of the frequency update.
336 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
338 * This function calls the transition notifiers and adjust_jiffies().
340 * It is called twice on all CPU frequency changes that have external effects.
342 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
343 struct cpufreq_freqs *freqs,
348 BUG_ON(irqs_disabled());
350 if (cpufreq_disabled())
353 freqs->policy = policy;
354 freqs->flags = cpufreq_driver->flags;
355 pr_debug("notification %u of frequency transition to %u kHz\n",
359 case CPUFREQ_PRECHANGE:
361 * Detect if the driver reported a value as "old frequency"
362 * which is not equal to what the cpufreq core thinks is
365 if (policy->cur && policy->cur != freqs->old) {
366 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
367 freqs->old, policy->cur);
368 freqs->old = policy->cur;
371 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
372 CPUFREQ_PRECHANGE, freqs);
374 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
377 case CPUFREQ_POSTCHANGE:
378 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
379 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
380 cpumask_pr_args(policy->cpus));
382 for_each_cpu(cpu, policy->cpus)
383 trace_cpu_frequency(freqs->new, cpu);
385 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
386 CPUFREQ_POSTCHANGE, freqs);
388 cpufreq_stats_record_transition(policy, freqs->new);
389 policy->cur = freqs->new;
393 /* Do post notifications when there are chances that transition has failed */
394 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
395 struct cpufreq_freqs *freqs, int transition_failed)
397 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
398 if (!transition_failed)
401 swap(freqs->old, freqs->new);
402 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
403 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
406 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
407 struct cpufreq_freqs *freqs)
411 * Catch double invocations of _begin() which lead to self-deadlock.
412 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
413 * doesn't invoke _begin() on their behalf, and hence the chances of
414 * double invocations are very low. Moreover, there are scenarios
415 * where these checks can emit false-positive warnings in these
416 * drivers; so we avoid that by skipping them altogether.
418 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
419 && current == policy->transition_task);
422 wait_event(policy->transition_wait, !policy->transition_ongoing);
424 spin_lock(&policy->transition_lock);
426 if (unlikely(policy->transition_ongoing)) {
427 spin_unlock(&policy->transition_lock);
431 policy->transition_ongoing = true;
432 policy->transition_task = current;
434 spin_unlock(&policy->transition_lock);
436 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
438 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
440 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
441 struct cpufreq_freqs *freqs, int transition_failed)
443 if (WARN_ON(!policy->transition_ongoing))
446 cpufreq_notify_post_transition(policy, freqs, transition_failed);
448 arch_set_freq_scale(policy->related_cpus,
450 policy->cpuinfo.max_freq);
452 policy->transition_ongoing = false;
453 policy->transition_task = NULL;
455 wake_up(&policy->transition_wait);
457 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
460 * Fast frequency switching status count. Positive means "enabled", negative
461 * means "disabled" and 0 means "not decided yet".
463 static int cpufreq_fast_switch_count;
464 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
466 static void cpufreq_list_transition_notifiers(void)
468 struct notifier_block *nb;
470 pr_info("Registered transition notifiers:\n");
472 mutex_lock(&cpufreq_transition_notifier_list.mutex);
474 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
475 pr_info("%pS\n", nb->notifier_call);
477 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
481 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
482 * @policy: cpufreq policy to enable fast frequency switching for.
484 * Try to enable fast frequency switching for @policy.
486 * The attempt will fail if there is at least one transition notifier registered
487 * at this point, as fast frequency switching is quite fundamentally at odds
488 * with transition notifiers. Thus if successful, it will make registration of
489 * transition notifiers fail going forward.
491 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
493 lockdep_assert_held(&policy->rwsem);
495 if (!policy->fast_switch_possible)
498 mutex_lock(&cpufreq_fast_switch_lock);
499 if (cpufreq_fast_switch_count >= 0) {
500 cpufreq_fast_switch_count++;
501 policy->fast_switch_enabled = true;
503 pr_warn("CPU%u: Fast frequency switching not enabled\n",
505 cpufreq_list_transition_notifiers();
507 mutex_unlock(&cpufreq_fast_switch_lock);
509 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
512 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
513 * @policy: cpufreq policy to disable fast frequency switching for.
515 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
517 mutex_lock(&cpufreq_fast_switch_lock);
518 if (policy->fast_switch_enabled) {
519 policy->fast_switch_enabled = false;
520 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
521 cpufreq_fast_switch_count--;
523 mutex_unlock(&cpufreq_fast_switch_lock);
525 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
528 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
530 * @policy: associated policy to interrogate
531 * @target_freq: target frequency to resolve.
533 * The target to driver frequency mapping is cached in the policy.
535 * Return: Lowest driver-supported frequency greater than or equal to the
536 * given target_freq, subject to policy (min/max) and driver limitations.
538 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
539 unsigned int target_freq)
541 target_freq = clamp_val(target_freq, policy->min, policy->max);
542 policy->cached_target_freq = target_freq;
544 if (cpufreq_driver->target_index) {
547 idx = cpufreq_frequency_table_target(policy, target_freq,
549 policy->cached_resolved_idx = idx;
550 return policy->freq_table[idx].frequency;
553 if (cpufreq_driver->resolve_freq)
554 return cpufreq_driver->resolve_freq(policy, target_freq);
558 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
560 unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
562 unsigned int latency;
564 if (policy->transition_delay_us)
565 return policy->transition_delay_us;
567 latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
570 * For platforms that can change the frequency very fast (< 10
571 * us), the above formula gives a decent transition delay. But
572 * for platforms where transition_latency is in milliseconds, it
573 * ends up giving unrealistic values.
575 * Cap the default transition delay to 10 ms, which seems to be
576 * a reasonable amount of time after which we should reevaluate
579 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
582 return LATENCY_MULTIPLIER;
584 EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
586 /*********************************************************************
588 *********************************************************************/
589 static ssize_t show_boost(struct kobject *kobj,
590 struct kobj_attribute *attr, char *buf)
592 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
595 static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
596 const char *buf, size_t count)
600 ret = sscanf(buf, "%d", &enable);
601 if (ret != 1 || enable < 0 || enable > 1)
604 if (cpufreq_boost_trigger_state(enable)) {
605 pr_err("%s: Cannot %s BOOST!\n",
606 __func__, enable ? "enable" : "disable");
610 pr_debug("%s: cpufreq BOOST %s\n",
611 __func__, enable ? "enabled" : "disabled");
615 define_one_global_rw(boost);
617 static struct cpufreq_governor *find_governor(const char *str_governor)
619 struct cpufreq_governor *t;
622 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
628 static struct cpufreq_governor *get_governor(const char *str_governor)
630 struct cpufreq_governor *t;
632 mutex_lock(&cpufreq_governor_mutex);
633 t = find_governor(str_governor);
637 if (!try_module_get(t->owner))
641 mutex_unlock(&cpufreq_governor_mutex);
646 static unsigned int cpufreq_parse_policy(char *str_governor)
648 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
649 return CPUFREQ_POLICY_PERFORMANCE;
651 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
652 return CPUFREQ_POLICY_POWERSAVE;
654 return CPUFREQ_POLICY_UNKNOWN;
658 * cpufreq_parse_governor - parse a governor string only for has_target()
659 * @str_governor: Governor name.
661 static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
663 struct cpufreq_governor *t;
665 t = get_governor(str_governor);
669 if (request_module("cpufreq_%s", str_governor))
672 return get_governor(str_governor);
676 * cpufreq_per_cpu_attr_read() / show_##file_name() -
677 * print out cpufreq information
679 * Write out information from cpufreq_driver->policy[cpu]; object must be
683 #define show_one(file_name, object) \
684 static ssize_t show_##file_name \
685 (struct cpufreq_policy *policy, char *buf) \
687 return sprintf(buf, "%u\n", policy->object); \
690 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
691 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
692 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
693 show_one(scaling_min_freq, min);
694 show_one(scaling_max_freq, max);
696 __weak unsigned int arch_freq_get_on_cpu(int cpu)
701 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
706 freq = arch_freq_get_on_cpu(policy->cpu);
708 ret = sprintf(buf, "%u\n", freq);
709 else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
710 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
712 ret = sprintf(buf, "%u\n", policy->cur);
717 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
719 #define store_one(file_name, object) \
720 static ssize_t store_##file_name \
721 (struct cpufreq_policy *policy, const char *buf, size_t count) \
726 ret = sscanf(buf, "%lu", &val); \
730 ret = freq_qos_update_request(policy->object##_freq_req, val);\
731 return ret >= 0 ? count : ret; \
734 store_one(scaling_min_freq, min);
735 store_one(scaling_max_freq, max);
738 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
740 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
743 unsigned int cur_freq = __cpufreq_get(policy);
746 return sprintf(buf, "%u\n", cur_freq);
748 return sprintf(buf, "<unknown>\n");
752 * show_scaling_governor - show the current policy for the specified CPU
754 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
756 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
757 return sprintf(buf, "powersave\n");
758 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
759 return sprintf(buf, "performance\n");
760 else if (policy->governor)
761 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
762 policy->governor->name);
767 * store_scaling_governor - store policy for the specified CPU
769 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
770 const char *buf, size_t count)
772 char str_governor[16];
775 ret = sscanf(buf, "%15s", str_governor);
779 if (cpufreq_driver->setpolicy) {
780 unsigned int new_pol;
782 new_pol = cpufreq_parse_policy(str_governor);
786 ret = cpufreq_set_policy(policy, NULL, new_pol);
788 struct cpufreq_governor *new_gov;
790 new_gov = cpufreq_parse_governor(str_governor);
794 ret = cpufreq_set_policy(policy, new_gov,
795 CPUFREQ_POLICY_UNKNOWN);
797 module_put(new_gov->owner);
800 return ret ? ret : count;
804 * show_scaling_driver - show the cpufreq driver currently loaded
806 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
808 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
812 * show_scaling_available_governors - show the available CPUfreq governors
814 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
818 struct cpufreq_governor *t;
821 i += sprintf(buf, "performance powersave");
825 mutex_lock(&cpufreq_governor_mutex);
826 for_each_governor(t) {
827 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
828 - (CPUFREQ_NAME_LEN + 2)))
830 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
832 mutex_unlock(&cpufreq_governor_mutex);
834 i += sprintf(&buf[i], "\n");
838 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
843 for_each_cpu(cpu, mask) {
845 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
846 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
847 if (i >= (PAGE_SIZE - 5))
850 i += sprintf(&buf[i], "\n");
853 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
856 * show_related_cpus - show the CPUs affected by each transition even if
857 * hw coordination is in use
859 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
861 return cpufreq_show_cpus(policy->related_cpus, buf);
865 * show_affected_cpus - show the CPUs affected by each transition
867 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
869 return cpufreq_show_cpus(policy->cpus, buf);
872 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
873 const char *buf, size_t count)
875 unsigned int freq = 0;
878 if (!policy->governor || !policy->governor->store_setspeed)
881 ret = sscanf(buf, "%u", &freq);
885 policy->governor->store_setspeed(policy, freq);
890 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
892 if (!policy->governor || !policy->governor->show_setspeed)
893 return sprintf(buf, "<unsupported>\n");
895 return policy->governor->show_setspeed(policy, buf);
899 * show_bios_limit - show the current cpufreq HW/BIOS limitation
901 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
905 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
907 return sprintf(buf, "%u\n", limit);
908 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
911 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
912 cpufreq_freq_attr_ro(cpuinfo_min_freq);
913 cpufreq_freq_attr_ro(cpuinfo_max_freq);
914 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
915 cpufreq_freq_attr_ro(scaling_available_governors);
916 cpufreq_freq_attr_ro(scaling_driver);
917 cpufreq_freq_attr_ro(scaling_cur_freq);
918 cpufreq_freq_attr_ro(bios_limit);
919 cpufreq_freq_attr_ro(related_cpus);
920 cpufreq_freq_attr_ro(affected_cpus);
921 cpufreq_freq_attr_rw(scaling_min_freq);
922 cpufreq_freq_attr_rw(scaling_max_freq);
923 cpufreq_freq_attr_rw(scaling_governor);
924 cpufreq_freq_attr_rw(scaling_setspeed);
926 static struct attribute *default_attrs[] = {
927 &cpuinfo_min_freq.attr,
928 &cpuinfo_max_freq.attr,
929 &cpuinfo_transition_latency.attr,
930 &scaling_min_freq.attr,
931 &scaling_max_freq.attr,
934 &scaling_governor.attr,
935 &scaling_driver.attr,
936 &scaling_available_governors.attr,
937 &scaling_setspeed.attr,
941 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
942 #define to_attr(a) container_of(a, struct freq_attr, attr)
944 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
946 struct cpufreq_policy *policy = to_policy(kobj);
947 struct freq_attr *fattr = to_attr(attr);
953 down_read(&policy->rwsem);
954 ret = fattr->show(policy, buf);
955 up_read(&policy->rwsem);
960 static ssize_t store(struct kobject *kobj, struct attribute *attr,
961 const char *buf, size_t count)
963 struct cpufreq_policy *policy = to_policy(kobj);
964 struct freq_attr *fattr = to_attr(attr);
965 ssize_t ret = -EINVAL;
971 * cpus_read_trylock() is used here to work around a circular lock
972 * dependency problem with respect to the cpufreq_register_driver().
974 if (!cpus_read_trylock())
977 if (cpu_online(policy->cpu)) {
978 down_write(&policy->rwsem);
979 ret = fattr->store(policy, buf, count);
980 up_write(&policy->rwsem);
988 static void cpufreq_sysfs_release(struct kobject *kobj)
990 struct cpufreq_policy *policy = to_policy(kobj);
991 pr_debug("last reference is dropped\n");
992 complete(&policy->kobj_unregister);
995 static const struct sysfs_ops sysfs_ops = {
1000 static struct kobj_type ktype_cpufreq = {
1001 .sysfs_ops = &sysfs_ops,
1002 .default_attrs = default_attrs,
1003 .release = cpufreq_sysfs_release,
1006 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
1008 struct device *dev = get_cpu_device(cpu);
1013 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1016 dev_dbg(dev, "%s: Adding symlink\n", __func__);
1017 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1018 dev_err(dev, "cpufreq symlink creation failed\n");
1021 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
1024 dev_dbg(dev, "%s: Removing symlink\n", __func__);
1025 sysfs_remove_link(&dev->kobj, "cpufreq");
1028 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1030 struct freq_attr **drv_attr;
1033 /* set up files for this cpu device */
1034 drv_attr = cpufreq_driver->attr;
1035 while (drv_attr && *drv_attr) {
1036 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1041 if (cpufreq_driver->get) {
1042 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1047 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1051 if (cpufreq_driver->bios_limit) {
1052 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1060 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1062 struct cpufreq_governor *gov = NULL;
1063 unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
1067 /* Update policy governor to the one used before hotplug. */
1068 gov = get_governor(policy->last_governor);
1070 pr_debug("Restoring governor %s for cpu %d\n",
1071 gov->name, policy->cpu);
1073 gov = get_governor(default_governor);
1077 gov = cpufreq_default_governor();
1078 __module_get(gov->owner);
1083 /* Use the default policy if there is no last_policy. */
1084 if (policy->last_policy) {
1085 pol = policy->last_policy;
1087 pol = cpufreq_parse_policy(default_governor);
1089 * In case the default governor is neither "performance"
1090 * nor "powersave", fall back to the initial policy
1091 * value set by the driver.
1093 if (pol == CPUFREQ_POLICY_UNKNOWN)
1094 pol = policy->policy;
1096 if (pol != CPUFREQ_POLICY_PERFORMANCE &&
1097 pol != CPUFREQ_POLICY_POWERSAVE)
1101 ret = cpufreq_set_policy(policy, gov, pol);
1103 module_put(gov->owner);
1108 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1112 /* Has this CPU been taken care of already? */
1113 if (cpumask_test_cpu(cpu, policy->cpus))
1116 down_write(&policy->rwsem);
1118 cpufreq_stop_governor(policy);
1120 cpumask_set_cpu(cpu, policy->cpus);
1123 ret = cpufreq_start_governor(policy);
1125 pr_err("%s: Failed to start governor\n", __func__);
1127 up_write(&policy->rwsem);
1131 void refresh_frequency_limits(struct cpufreq_policy *policy)
1133 if (!policy_is_inactive(policy)) {
1134 pr_debug("updating policy for CPU %u\n", policy->cpu);
1136 cpufreq_set_policy(policy, policy->governor, policy->policy);
1139 EXPORT_SYMBOL(refresh_frequency_limits);
1141 static void handle_update(struct work_struct *work)
1143 struct cpufreq_policy *policy =
1144 container_of(work, struct cpufreq_policy, update);
1146 pr_debug("handle_update for cpu %u called\n", policy->cpu);
1147 down_write(&policy->rwsem);
1148 refresh_frequency_limits(policy);
1149 up_write(&policy->rwsem);
1152 static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1155 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1157 schedule_work(&policy->update);
1161 static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1164 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1166 schedule_work(&policy->update);
1170 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1172 struct kobject *kobj;
1173 struct completion *cmp;
1175 down_write(&policy->rwsem);
1176 cpufreq_stats_free_table(policy);
1177 kobj = &policy->kobj;
1178 cmp = &policy->kobj_unregister;
1179 up_write(&policy->rwsem);
1183 * We need to make sure that the underlying kobj is
1184 * actually not referenced anymore by anybody before we
1185 * proceed with unloading.
1187 pr_debug("waiting for dropping of refcount\n");
1188 wait_for_completion(cmp);
1189 pr_debug("wait complete\n");
1192 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1194 struct cpufreq_policy *policy;
1195 struct device *dev = get_cpu_device(cpu);
1201 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1205 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1206 goto err_free_policy;
1208 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1209 goto err_free_cpumask;
1211 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1212 goto err_free_rcpumask;
1214 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1215 cpufreq_global_kobject, "policy%u", cpu);
1217 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1219 * The entire policy object will be freed below, but the extra
1220 * memory allocated for the kobject name needs to be freed by
1221 * releasing the kobject.
1223 kobject_put(&policy->kobj);
1224 goto err_free_real_cpus;
1227 freq_constraints_init(&policy->constraints);
1229 policy->nb_min.notifier_call = cpufreq_notifier_min;
1230 policy->nb_max.notifier_call = cpufreq_notifier_max;
1232 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1235 dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
1236 ret, cpumask_pr_args(policy->cpus));
1237 goto err_kobj_remove;
1240 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1243 dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
1244 ret, cpumask_pr_args(policy->cpus));
1245 goto err_min_qos_notifier;
1248 INIT_LIST_HEAD(&policy->policy_list);
1249 init_rwsem(&policy->rwsem);
1250 spin_lock_init(&policy->transition_lock);
1251 init_waitqueue_head(&policy->transition_wait);
1252 init_completion(&policy->kobj_unregister);
1253 INIT_WORK(&policy->update, handle_update);
1258 err_min_qos_notifier:
1259 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1262 cpufreq_policy_put_kobj(policy);
1264 free_cpumask_var(policy->real_cpus);
1266 free_cpumask_var(policy->related_cpus);
1268 free_cpumask_var(policy->cpus);
1275 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1277 unsigned long flags;
1280 /* Remove policy from list */
1281 write_lock_irqsave(&cpufreq_driver_lock, flags);
1282 list_del(&policy->policy_list);
1284 for_each_cpu(cpu, policy->related_cpus)
1285 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1286 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1288 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1290 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1293 /* Cancel any pending policy->update work before freeing the policy. */
1294 cancel_work_sync(&policy->update);
1296 if (policy->max_freq_req) {
1298 * CPUFREQ_CREATE_POLICY notification is sent only after
1299 * successfully adding max_freq_req request.
1301 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1302 CPUFREQ_REMOVE_POLICY, policy);
1303 freq_qos_remove_request(policy->max_freq_req);
1306 freq_qos_remove_request(policy->min_freq_req);
1307 kfree(policy->min_freq_req);
1309 cpufreq_policy_put_kobj(policy);
1310 free_cpumask_var(policy->real_cpus);
1311 free_cpumask_var(policy->related_cpus);
1312 free_cpumask_var(policy->cpus);
1316 static int cpufreq_online(unsigned int cpu)
1318 struct cpufreq_policy *policy;
1320 unsigned long flags;
1324 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1326 /* Check if this CPU already has a policy to manage it */
1327 policy = per_cpu(cpufreq_cpu_data, cpu);
1329 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1330 if (!policy_is_inactive(policy))
1331 return cpufreq_add_policy_cpu(policy, cpu);
1333 /* This is the only online CPU for the policy. Start over. */
1335 down_write(&policy->rwsem);
1337 policy->governor = NULL;
1338 up_write(&policy->rwsem);
1341 policy = cpufreq_policy_alloc(cpu);
1346 if (!new_policy && cpufreq_driver->online) {
1347 ret = cpufreq_driver->online(policy);
1349 pr_debug("%s: %d: initialization failed\n", __func__,
1351 goto out_exit_policy;
1354 /* Recover policy->cpus using related_cpus */
1355 cpumask_copy(policy->cpus, policy->related_cpus);
1357 cpumask_copy(policy->cpus, cpumask_of(cpu));
1360 * Call driver. From then on the cpufreq must be able
1361 * to accept all calls to ->verify and ->setpolicy for this CPU.
1363 ret = cpufreq_driver->init(policy);
1365 pr_debug("%s: %d: initialization failed\n", __func__,
1367 goto out_free_policy;
1370 ret = cpufreq_table_validate_and_sort(policy);
1372 goto out_exit_policy;
1374 /* related_cpus should at least include policy->cpus. */
1375 cpumask_copy(policy->related_cpus, policy->cpus);
1378 down_write(&policy->rwsem);
1380 * affected cpus must always be the one, which are online. We aren't
1381 * managing offline cpus here.
1383 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1386 for_each_cpu(j, policy->related_cpus) {
1387 per_cpu(cpufreq_cpu_data, j) = policy;
1388 add_cpu_dev_symlink(policy, j);
1391 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1393 if (!policy->min_freq_req) {
1395 goto out_destroy_policy;
1398 ret = freq_qos_add_request(&policy->constraints,
1399 policy->min_freq_req, FREQ_QOS_MIN,
1403 * So we don't call freq_qos_remove_request() for an
1404 * uninitialized request.
1406 kfree(policy->min_freq_req);
1407 policy->min_freq_req = NULL;
1408 goto out_destroy_policy;
1412 * This must be initialized right here to avoid calling
1413 * freq_qos_remove_request() on uninitialized request in case
1416 policy->max_freq_req = policy->min_freq_req + 1;
1418 ret = freq_qos_add_request(&policy->constraints,
1419 policy->max_freq_req, FREQ_QOS_MAX,
1422 policy->max_freq_req = NULL;
1423 goto out_destroy_policy;
1426 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1427 CPUFREQ_CREATE_POLICY, policy);
1430 if (cpufreq_driver->get && has_target()) {
1431 policy->cur = cpufreq_driver->get(policy->cpu);
1434 pr_err("%s: ->get() failed\n", __func__);
1435 goto out_destroy_policy;
1440 * Sometimes boot loaders set CPU frequency to a value outside of
1441 * frequency table present with cpufreq core. In such cases CPU might be
1442 * unstable if it has to run on that frequency for long duration of time
1443 * and so its better to set it to a frequency which is specified in
1444 * freq-table. This also makes cpufreq stats inconsistent as
1445 * cpufreq-stats would fail to register because current frequency of CPU
1446 * isn't found in freq-table.
1448 * Because we don't want this change to effect boot process badly, we go
1449 * for the next freq which is >= policy->cur ('cur' must be set by now,
1450 * otherwise we will end up setting freq to lowest of the table as 'cur'
1451 * is initialized to zero).
1453 * We are passing target-freq as "policy->cur - 1" otherwise
1454 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1455 * equal to target-freq.
1457 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1459 unsigned int old_freq = policy->cur;
1461 /* Are we running at unknown frequency ? */
1462 ret = cpufreq_frequency_table_get_index(policy, old_freq);
1463 if (ret == -EINVAL) {
1464 ret = __cpufreq_driver_target(policy, old_freq - 1,
1465 CPUFREQ_RELATION_L);
1468 * Reaching here after boot in a few seconds may not
1469 * mean that system will remain stable at "unknown"
1470 * frequency for longer duration. Hence, a BUG_ON().
1473 pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
1474 __func__, policy->cpu, old_freq, policy->cur);
1479 ret = cpufreq_add_dev_interface(policy);
1481 goto out_destroy_policy;
1483 cpufreq_stats_create_table(policy);
1485 write_lock_irqsave(&cpufreq_driver_lock, flags);
1486 list_add(&policy->policy_list, &cpufreq_policy_list);
1487 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1490 ret = cpufreq_init_policy(policy);
1492 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1493 __func__, cpu, ret);
1494 goto out_destroy_policy;
1497 up_write(&policy->rwsem);
1499 kobject_uevent(&policy->kobj, KOBJ_ADD);
1501 /* Callback for handling stuff after policy is ready */
1502 if (cpufreq_driver->ready)
1503 cpufreq_driver->ready(policy);
1505 if (cpufreq_thermal_control_enabled(cpufreq_driver))
1506 policy->cdev = of_cpufreq_cooling_register(policy);
1508 pr_debug("initialization complete\n");
1513 for_each_cpu(j, policy->real_cpus)
1514 remove_cpu_dev_symlink(policy, get_cpu_device(j));
1516 up_write(&policy->rwsem);
1519 if (cpufreq_driver->exit)
1520 cpufreq_driver->exit(policy);
1523 cpufreq_policy_free(policy);
1528 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1530 * @sif: Subsystem interface structure pointer (not used)
1532 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1534 struct cpufreq_policy *policy;
1535 unsigned cpu = dev->id;
1538 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1540 if (cpu_online(cpu)) {
1541 ret = cpufreq_online(cpu);
1546 /* Create sysfs link on CPU registration */
1547 policy = per_cpu(cpufreq_cpu_data, cpu);
1549 add_cpu_dev_symlink(policy, cpu);
1554 static int cpufreq_offline(unsigned int cpu)
1556 struct cpufreq_policy *policy;
1559 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1561 policy = cpufreq_cpu_get_raw(cpu);
1563 pr_debug("%s: No cpu_data found\n", __func__);
1567 down_write(&policy->rwsem);
1569 cpufreq_stop_governor(policy);
1571 cpumask_clear_cpu(cpu, policy->cpus);
1573 if (policy_is_inactive(policy)) {
1575 strncpy(policy->last_governor, policy->governor->name,
1578 policy->last_policy = policy->policy;
1579 } else if (cpu == policy->cpu) {
1580 /* Nominate new CPU */
1581 policy->cpu = cpumask_any(policy->cpus);
1584 /* Start governor again for active policy */
1585 if (!policy_is_inactive(policy)) {
1587 ret = cpufreq_start_governor(policy);
1589 pr_err("%s: Failed to start governor\n", __func__);
1595 if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1596 cpufreq_cooling_unregister(policy->cdev);
1597 policy->cdev = NULL;
1600 if (cpufreq_driver->stop_cpu)
1601 cpufreq_driver->stop_cpu(policy);
1604 cpufreq_exit_governor(policy);
1607 * Perform the ->offline() during light-weight tear-down, as
1608 * that allows fast recovery when the CPU comes back.
1610 if (cpufreq_driver->offline) {
1611 cpufreq_driver->offline(policy);
1612 } else if (cpufreq_driver->exit) {
1613 cpufreq_driver->exit(policy);
1614 policy->freq_table = NULL;
1618 up_write(&policy->rwsem);
1623 * cpufreq_remove_dev - remove a CPU device
1625 * Removes the cpufreq interface for a CPU device.
1627 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1629 unsigned int cpu = dev->id;
1630 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1635 if (cpu_online(cpu))
1636 cpufreq_offline(cpu);
1638 cpumask_clear_cpu(cpu, policy->real_cpus);
1639 remove_cpu_dev_symlink(policy, dev);
1641 if (cpumask_empty(policy->real_cpus)) {
1642 /* We did light-weight exit earlier, do full tear down now */
1643 if (cpufreq_driver->offline)
1644 cpufreq_driver->exit(policy);
1646 cpufreq_policy_free(policy);
1651 * cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
1652 * @policy: Policy managing CPUs.
1653 * @new_freq: New CPU frequency.
1655 * Adjust to the current frequency first and clean up later by either calling
1656 * cpufreq_update_policy(), or scheduling handle_update().
1658 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1659 unsigned int new_freq)
1661 struct cpufreq_freqs freqs;
1663 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1664 policy->cur, new_freq);
1666 freqs.old = policy->cur;
1667 freqs.new = new_freq;
1669 cpufreq_freq_transition_begin(policy, &freqs);
1670 cpufreq_freq_transition_end(policy, &freqs, 0);
1673 static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1675 unsigned int new_freq;
1677 new_freq = cpufreq_driver->get(policy->cpu);
1682 * If fast frequency switching is used with the given policy, the check
1683 * against policy->cur is pointless, so skip it in that case.
1685 if (policy->fast_switch_enabled || !has_target())
1688 if (policy->cur != new_freq) {
1689 cpufreq_out_of_sync(policy, new_freq);
1691 schedule_work(&policy->update);
1698 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1701 * This is the last known freq, without actually getting it from the driver.
1702 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1704 unsigned int cpufreq_quick_get(unsigned int cpu)
1706 struct cpufreq_policy *policy;
1707 unsigned int ret_freq = 0;
1708 unsigned long flags;
1710 read_lock_irqsave(&cpufreq_driver_lock, flags);
1712 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1713 ret_freq = cpufreq_driver->get(cpu);
1714 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1718 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1720 policy = cpufreq_cpu_get(cpu);
1722 ret_freq = policy->cur;
1723 cpufreq_cpu_put(policy);
1728 EXPORT_SYMBOL(cpufreq_quick_get);
1731 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1734 * Just return the max possible frequency for a given CPU.
1736 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1738 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1739 unsigned int ret_freq = 0;
1742 ret_freq = policy->max;
1743 cpufreq_cpu_put(policy);
1748 EXPORT_SYMBOL(cpufreq_quick_get_max);
1751 * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
1754 * The default return value is the max_freq field of cpuinfo.
1756 __weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
1758 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1759 unsigned int ret_freq = 0;
1762 ret_freq = policy->cpuinfo.max_freq;
1763 cpufreq_cpu_put(policy);
1768 EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
1770 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1772 if (unlikely(policy_is_inactive(policy)))
1775 return cpufreq_verify_current_freq(policy, true);
1779 * cpufreq_get - get the current CPU frequency (in kHz)
1782 * Get the CPU current (static) CPU frequency
1784 unsigned int cpufreq_get(unsigned int cpu)
1786 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1787 unsigned int ret_freq = 0;
1790 down_read(&policy->rwsem);
1791 if (cpufreq_driver->get)
1792 ret_freq = __cpufreq_get(policy);
1793 up_read(&policy->rwsem);
1795 cpufreq_cpu_put(policy);
1800 EXPORT_SYMBOL(cpufreq_get);
1802 static struct subsys_interface cpufreq_interface = {
1804 .subsys = &cpu_subsys,
1805 .add_dev = cpufreq_add_dev,
1806 .remove_dev = cpufreq_remove_dev,
1810 * In case platform wants some specific frequency to be configured
1813 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1817 if (!policy->suspend_freq) {
1818 pr_debug("%s: suspend_freq not defined\n", __func__);
1822 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1823 policy->suspend_freq);
1825 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1826 CPUFREQ_RELATION_H);
1828 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1829 __func__, policy->suspend_freq, ret);
1833 EXPORT_SYMBOL(cpufreq_generic_suspend);
1836 * cpufreq_suspend() - Suspend CPUFreq governors.
1838 * Called during system wide Suspend/Hibernate cycles for suspending governors
1839 * as some platforms can't change frequency after this point in suspend cycle.
1840 * Because some of the devices (like: i2c, regulators, etc) they use for
1841 * changing frequency are suspended quickly after this point.
1843 void cpufreq_suspend(void)
1845 struct cpufreq_policy *policy;
1847 if (!cpufreq_driver)
1850 if (!has_target() && !cpufreq_driver->suspend)
1853 pr_debug("%s: Suspending Governors\n", __func__);
1855 for_each_active_policy(policy) {
1857 down_write(&policy->rwsem);
1858 cpufreq_stop_governor(policy);
1859 up_write(&policy->rwsem);
1862 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1863 pr_err("%s: Failed to suspend driver: %s\n", __func__,
1864 cpufreq_driver->name);
1868 cpufreq_suspended = true;
1872 * cpufreq_resume() - Resume CPUFreq governors.
1874 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1875 * are suspended with cpufreq_suspend().
1877 void cpufreq_resume(void)
1879 struct cpufreq_policy *policy;
1882 if (!cpufreq_driver)
1885 if (unlikely(!cpufreq_suspended))
1888 cpufreq_suspended = false;
1890 if (!has_target() && !cpufreq_driver->resume)
1893 pr_debug("%s: Resuming Governors\n", __func__);
1895 for_each_active_policy(policy) {
1896 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1897 pr_err("%s: Failed to resume driver: %p\n", __func__,
1899 } else if (has_target()) {
1900 down_write(&policy->rwsem);
1901 ret = cpufreq_start_governor(policy);
1902 up_write(&policy->rwsem);
1905 pr_err("%s: Failed to start governor for policy: %p\n",
1912 * cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
1913 * @flags: Flags to test against the current cpufreq driver's flags.
1915 * Assumes that the driver is there, so callers must ensure that this is the
1918 bool cpufreq_driver_test_flags(u16 flags)
1920 return !!(cpufreq_driver->flags & flags);
1924 * cpufreq_get_current_driver - Return the current driver's name.
1926 * Return the name string of the currently registered cpufreq driver or NULL if
1929 const char *cpufreq_get_current_driver(void)
1932 return cpufreq_driver->name;
1936 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1939 * cpufreq_get_driver_data - Return current driver data.
1941 * Return the private data of the currently registered cpufreq driver, or NULL
1942 * if no cpufreq driver has been registered.
1944 void *cpufreq_get_driver_data(void)
1947 return cpufreq_driver->driver_data;
1951 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1953 /*********************************************************************
1954 * NOTIFIER LISTS INTERFACE *
1955 *********************************************************************/
1958 * cpufreq_register_notifier - Register a notifier with cpufreq.
1959 * @nb: notifier function to register.
1960 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
1962 * Add a notifier to one of two lists: either a list of notifiers that run on
1963 * clock rate changes (once before and once after every transition), or a list
1964 * of notifiers that ron on cpufreq policy changes.
1966 * This function may sleep and it has the same return values as
1967 * blocking_notifier_chain_register().
1969 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1973 if (cpufreq_disabled())
1977 case CPUFREQ_TRANSITION_NOTIFIER:
1978 mutex_lock(&cpufreq_fast_switch_lock);
1980 if (cpufreq_fast_switch_count > 0) {
1981 mutex_unlock(&cpufreq_fast_switch_lock);
1984 ret = srcu_notifier_chain_register(
1985 &cpufreq_transition_notifier_list, nb);
1987 cpufreq_fast_switch_count--;
1989 mutex_unlock(&cpufreq_fast_switch_lock);
1991 case CPUFREQ_POLICY_NOTIFIER:
1992 ret = blocking_notifier_chain_register(
1993 &cpufreq_policy_notifier_list, nb);
2001 EXPORT_SYMBOL(cpufreq_register_notifier);
2004 * cpufreq_unregister_notifier - Unregister a notifier from cpufreq.
2005 * @nb: notifier block to be unregistered.
2006 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2008 * Remove a notifier from one of the cpufreq notifier lists.
2010 * This function may sleep and it has the same return values as
2011 * blocking_notifier_chain_unregister().
2013 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
2017 if (cpufreq_disabled())
2021 case CPUFREQ_TRANSITION_NOTIFIER:
2022 mutex_lock(&cpufreq_fast_switch_lock);
2024 ret = srcu_notifier_chain_unregister(
2025 &cpufreq_transition_notifier_list, nb);
2026 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
2027 cpufreq_fast_switch_count++;
2029 mutex_unlock(&cpufreq_fast_switch_lock);
2031 case CPUFREQ_POLICY_NOTIFIER:
2032 ret = blocking_notifier_chain_unregister(
2033 &cpufreq_policy_notifier_list, nb);
2041 EXPORT_SYMBOL(cpufreq_unregister_notifier);
2044 /*********************************************************************
2046 *********************************************************************/
2049 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
2050 * @policy: cpufreq policy to switch the frequency for.
2051 * @target_freq: New frequency to set (may be approximate).
2053 * Carry out a fast frequency switch without sleeping.
2055 * The driver's ->fast_switch() callback invoked by this function must be
2056 * suitable for being called from within RCU-sched read-side critical sections
2057 * and it is expected to select the minimum available frequency greater than or
2058 * equal to @target_freq (CPUFREQ_RELATION_L).
2060 * This function must not be called if policy->fast_switch_enabled is unset.
2062 * Governors calling this function must guarantee that it will never be invoked
2063 * twice in parallel for the same policy and that it will never be called in
2064 * parallel with either ->target() or ->target_index() for the same policy.
2066 * Returns the actual frequency set for the CPU.
2068 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2069 * error condition, the hardware configuration must be preserved.
2071 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2072 unsigned int target_freq)
2077 target_freq = clamp_val(target_freq, policy->min, policy->max);
2078 freq = cpufreq_driver->fast_switch(policy, target_freq);
2084 arch_set_freq_scale(policy->related_cpus, freq,
2085 policy->cpuinfo.max_freq);
2086 cpufreq_stats_record_transition(policy, freq);
2088 if (trace_cpu_frequency_enabled()) {
2089 for_each_cpu(cpu, policy->cpus)
2090 trace_cpu_frequency(freq, cpu);
2095 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2098 * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
2100 * @min_perf: Minimum (required) performance level (units of @capacity).
2101 * @target_perf: Target (desired) performance level (units of @capacity).
2102 * @capacity: Capacity of the target CPU.
2104 * Carry out a fast performance level switch of @cpu without sleeping.
2106 * The driver's ->adjust_perf() callback invoked by this function must be
2107 * suitable for being called from within RCU-sched read-side critical sections
2108 * and it is expected to select a suitable performance level equal to or above
2109 * @min_perf and preferably equal to or below @target_perf.
2111 * This function must not be called if policy->fast_switch_enabled is unset.
2113 * Governors calling this function must guarantee that it will never be invoked
2114 * twice in parallel for the same CPU and that it will never be called in
2115 * parallel with either ->target() or ->target_index() or ->fast_switch() for
2118 void cpufreq_driver_adjust_perf(unsigned int cpu,
2119 unsigned long min_perf,
2120 unsigned long target_perf,
2121 unsigned long capacity)
2123 cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
2127 * cpufreq_driver_has_adjust_perf - Check "direct fast switch" callback.
2129 * Return 'true' if the ->adjust_perf callback is present for the
2130 * current driver or 'false' otherwise.
2132 bool cpufreq_driver_has_adjust_perf(void)
2134 return !!cpufreq_driver->adjust_perf;
2137 /* Must set freqs->new to intermediate frequency */
2138 static int __target_intermediate(struct cpufreq_policy *policy,
2139 struct cpufreq_freqs *freqs, int index)
2143 freqs->new = cpufreq_driver->get_intermediate(policy, index);
2145 /* We don't need to switch to intermediate freq */
2149 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2150 __func__, policy->cpu, freqs->old, freqs->new);
2152 cpufreq_freq_transition_begin(policy, freqs);
2153 ret = cpufreq_driver->target_intermediate(policy, index);
2154 cpufreq_freq_transition_end(policy, freqs, ret);
2157 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2163 static int __target_index(struct cpufreq_policy *policy, int index)
2165 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2166 unsigned int restore_freq, intermediate_freq = 0;
2167 unsigned int newfreq = policy->freq_table[index].frequency;
2168 int retval = -EINVAL;
2171 if (newfreq == policy->cur)
2174 /* Save last value to restore later on errors */
2175 restore_freq = policy->cur;
2177 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2179 /* Handle switching to intermediate frequency */
2180 if (cpufreq_driver->get_intermediate) {
2181 retval = __target_intermediate(policy, &freqs, index);
2185 intermediate_freq = freqs.new;
2186 /* Set old freq to intermediate */
2187 if (intermediate_freq)
2188 freqs.old = freqs.new;
2191 freqs.new = newfreq;
2192 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2193 __func__, policy->cpu, freqs.old, freqs.new);
2195 cpufreq_freq_transition_begin(policy, &freqs);
2198 retval = cpufreq_driver->target_index(policy, index);
2200 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2204 cpufreq_freq_transition_end(policy, &freqs, retval);
2207 * Failed after setting to intermediate freq? Driver should have
2208 * reverted back to initial frequency and so should we. Check
2209 * here for intermediate_freq instead of get_intermediate, in
2210 * case we haven't switched to intermediate freq at all.
2212 if (unlikely(retval && intermediate_freq)) {
2213 freqs.old = intermediate_freq;
2214 freqs.new = restore_freq;
2215 cpufreq_freq_transition_begin(policy, &freqs);
2216 cpufreq_freq_transition_end(policy, &freqs, 0);
2223 int __cpufreq_driver_target(struct cpufreq_policy *policy,
2224 unsigned int target_freq,
2225 unsigned int relation)
2227 unsigned int old_target_freq = target_freq;
2230 if (cpufreq_disabled())
2233 /* Make sure that target_freq is within supported range */
2234 target_freq = clamp_val(target_freq, policy->min, policy->max);
2236 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2237 policy->cpu, target_freq, relation, old_target_freq);
2240 * This might look like a redundant call as we are checking it again
2241 * after finding index. But it is left intentionally for cases where
2242 * exactly same freq is called again and so we can save on few function
2245 if (target_freq == policy->cur &&
2246 !(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS))
2249 if (cpufreq_driver->target)
2250 return cpufreq_driver->target(policy, target_freq, relation);
2252 if (!cpufreq_driver->target_index)
2255 index = cpufreq_frequency_table_target(policy, target_freq, relation);
2257 return __target_index(policy, index);
2259 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2261 int cpufreq_driver_target(struct cpufreq_policy *policy,
2262 unsigned int target_freq,
2263 unsigned int relation)
2267 down_write(&policy->rwsem);
2269 ret = __cpufreq_driver_target(policy, target_freq, relation);
2271 up_write(&policy->rwsem);
2275 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2277 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2282 static int cpufreq_init_governor(struct cpufreq_policy *policy)
2286 /* Don't start any governor operations if we are entering suspend */
2287 if (cpufreq_suspended)
2290 * Governor might not be initiated here if ACPI _PPC changed
2291 * notification happened, so check it.
2293 if (!policy->governor)
2296 /* Platform doesn't want dynamic frequency switching ? */
2297 if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING &&
2298 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2299 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2302 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2303 policy->governor->name, gov->name);
2304 policy->governor = gov;
2310 if (!try_module_get(policy->governor->owner))
2313 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2315 if (policy->governor->init) {
2316 ret = policy->governor->init(policy);
2318 module_put(policy->governor->owner);
2323 policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET);
2328 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2330 if (cpufreq_suspended || !policy->governor)
2333 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2335 if (policy->governor->exit)
2336 policy->governor->exit(policy);
2338 module_put(policy->governor->owner);
2341 int cpufreq_start_governor(struct cpufreq_policy *policy)
2345 if (cpufreq_suspended)
2348 if (!policy->governor)
2351 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2353 if (cpufreq_driver->get)
2354 cpufreq_verify_current_freq(policy, false);
2356 if (policy->governor->start) {
2357 ret = policy->governor->start(policy);
2362 if (policy->governor->limits)
2363 policy->governor->limits(policy);
2368 void cpufreq_stop_governor(struct cpufreq_policy *policy)
2370 if (cpufreq_suspended || !policy->governor)
2373 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2375 if (policy->governor->stop)
2376 policy->governor->stop(policy);
2379 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2381 if (cpufreq_suspended || !policy->governor)
2384 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2386 if (policy->governor->limits)
2387 policy->governor->limits(policy);
2390 int cpufreq_register_governor(struct cpufreq_governor *governor)
2397 if (cpufreq_disabled())
2400 mutex_lock(&cpufreq_governor_mutex);
2403 if (!find_governor(governor->name)) {
2405 list_add(&governor->governor_list, &cpufreq_governor_list);
2408 mutex_unlock(&cpufreq_governor_mutex);
2411 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2413 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2415 struct cpufreq_policy *policy;
2416 unsigned long flags;
2421 if (cpufreq_disabled())
2424 /* clear last_governor for all inactive policies */
2425 read_lock_irqsave(&cpufreq_driver_lock, flags);
2426 for_each_inactive_policy(policy) {
2427 if (!strcmp(policy->last_governor, governor->name)) {
2428 policy->governor = NULL;
2429 strcpy(policy->last_governor, "\0");
2432 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2434 mutex_lock(&cpufreq_governor_mutex);
2435 list_del(&governor->governor_list);
2436 mutex_unlock(&cpufreq_governor_mutex);
2438 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2441 /*********************************************************************
2442 * POLICY INTERFACE *
2443 *********************************************************************/
2446 * cpufreq_get_policy - get the current cpufreq_policy
2447 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2449 * @cpu: CPU to find the policy for
2451 * Reads the current cpufreq policy.
2453 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2455 struct cpufreq_policy *cpu_policy;
2459 cpu_policy = cpufreq_cpu_get(cpu);
2463 memcpy(policy, cpu_policy, sizeof(*policy));
2465 cpufreq_cpu_put(cpu_policy);
2468 EXPORT_SYMBOL(cpufreq_get_policy);
2471 * cpufreq_set_policy - Modify cpufreq policy parameters.
2472 * @policy: Policy object to modify.
2473 * @new_gov: Policy governor pointer.
2474 * @new_pol: Policy value (for drivers with built-in governors).
2476 * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
2477 * limits to be set for the policy, update @policy with the verified limits
2478 * values and either invoke the driver's ->setpolicy() callback (if present) or
2479 * carry out a governor update for @policy. That is, run the current governor's
2480 * ->limits() callback (if @new_gov points to the same object as the one in
2481 * @policy) or replace the governor for @policy with @new_gov.
2483 * The cpuinfo part of @policy is not updated by this function.
2485 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2486 struct cpufreq_governor *new_gov,
2487 unsigned int new_pol)
2489 struct cpufreq_policy_data new_data;
2490 struct cpufreq_governor *old_gov;
2493 memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2494 new_data.freq_table = policy->freq_table;
2495 new_data.cpu = policy->cpu;
2497 * PM QoS framework collects all the requests from users and provide us
2498 * the final aggregated value here.
2500 new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2501 new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2503 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2504 new_data.cpu, new_data.min, new_data.max);
2507 * Verify that the CPU speed can be set within these limits and make sure
2510 ret = cpufreq_driver->verify(&new_data);
2514 policy->min = new_data.min;
2515 policy->max = new_data.max;
2516 trace_cpu_frequency_limits(policy);
2518 policy->cached_target_freq = UINT_MAX;
2520 pr_debug("new min and max freqs are %u - %u kHz\n",
2521 policy->min, policy->max);
2523 if (cpufreq_driver->setpolicy) {
2524 policy->policy = new_pol;
2525 pr_debug("setting range\n");
2526 return cpufreq_driver->setpolicy(policy);
2529 if (new_gov == policy->governor) {
2530 pr_debug("governor limits update\n");
2531 cpufreq_governor_limits(policy);
2535 pr_debug("governor switch\n");
2537 /* save old, working values */
2538 old_gov = policy->governor;
2539 /* end old governor */
2541 cpufreq_stop_governor(policy);
2542 cpufreq_exit_governor(policy);
2545 /* start new governor */
2546 policy->governor = new_gov;
2547 ret = cpufreq_init_governor(policy);
2549 ret = cpufreq_start_governor(policy);
2551 pr_debug("governor change\n");
2552 sched_cpufreq_governor_change(policy, old_gov);
2555 cpufreq_exit_governor(policy);
2558 /* new governor failed, so re-start old one */
2559 pr_debug("starting governor %s failed\n", policy->governor->name);
2561 policy->governor = old_gov;
2562 if (cpufreq_init_governor(policy))
2563 policy->governor = NULL;
2565 cpufreq_start_governor(policy);
2572 * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2573 * @cpu: CPU to re-evaluate the policy for.
2575 * Update the current frequency for the cpufreq policy of @cpu and use
2576 * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2577 * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2578 * for the policy in question, among other things.
2580 void cpufreq_update_policy(unsigned int cpu)
2582 struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2588 * BIOS might change freq behind our back
2589 * -> ask driver for current freq and notify governors about a change
2591 if (cpufreq_driver->get && has_target() &&
2592 (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2595 refresh_frequency_limits(policy);
2598 cpufreq_cpu_release(policy);
2600 EXPORT_SYMBOL(cpufreq_update_policy);
2603 * cpufreq_update_limits - Update policy limits for a given CPU.
2604 * @cpu: CPU to update the policy limits for.
2606 * Invoke the driver's ->update_limits callback if present or call
2607 * cpufreq_update_policy() for @cpu.
2609 void cpufreq_update_limits(unsigned int cpu)
2611 if (cpufreq_driver->update_limits)
2612 cpufreq_driver->update_limits(cpu);
2614 cpufreq_update_policy(cpu);
2616 EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2618 /*********************************************************************
2620 *********************************************************************/
2621 static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
2625 if (!policy->freq_table)
2628 ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
2630 pr_err("%s: Policy frequency update failed\n", __func__);
2634 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2641 int cpufreq_boost_trigger_state(int state)
2643 struct cpufreq_policy *policy;
2644 unsigned long flags;
2647 if (cpufreq_driver->boost_enabled == state)
2650 write_lock_irqsave(&cpufreq_driver_lock, flags);
2651 cpufreq_driver->boost_enabled = state;
2652 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2655 for_each_active_policy(policy) {
2656 ret = cpufreq_driver->set_boost(policy, state);
2658 goto err_reset_state;
2667 write_lock_irqsave(&cpufreq_driver_lock, flags);
2668 cpufreq_driver->boost_enabled = !state;
2669 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2671 pr_err("%s: Cannot %s BOOST\n",
2672 __func__, state ? "enable" : "disable");
2677 static bool cpufreq_boost_supported(void)
2679 return cpufreq_driver->set_boost;
2682 static int create_boost_sysfs_file(void)
2686 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2688 pr_err("%s: cannot register global BOOST sysfs file\n",
2694 static void remove_boost_sysfs_file(void)
2696 if (cpufreq_boost_supported())
2697 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2700 int cpufreq_enable_boost_support(void)
2702 if (!cpufreq_driver)
2705 if (cpufreq_boost_supported())
2708 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2710 /* This will get removed on driver unregister */
2711 return create_boost_sysfs_file();
2713 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2715 int cpufreq_boost_enabled(void)
2717 return cpufreq_driver->boost_enabled;
2719 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2721 /*********************************************************************
2722 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2723 *********************************************************************/
2724 static enum cpuhp_state hp_online;
2726 static int cpuhp_cpufreq_online(unsigned int cpu)
2728 cpufreq_online(cpu);
2733 static int cpuhp_cpufreq_offline(unsigned int cpu)
2735 cpufreq_offline(cpu);
2741 * cpufreq_register_driver - register a CPU Frequency driver
2742 * @driver_data: A struct cpufreq_driver containing the values#
2743 * submitted by the CPU Frequency driver.
2745 * Registers a CPU Frequency driver to this core code. This code
2746 * returns zero on success, -EEXIST when another driver got here first
2747 * (and isn't unregistered in the meantime).
2750 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2752 unsigned long flags;
2755 if (cpufreq_disabled())
2759 * The cpufreq core depends heavily on the availability of device
2760 * structure, make sure they are available before proceeding further.
2762 if (!get_cpu_device(0))
2763 return -EPROBE_DEFER;
2765 if (!driver_data || !driver_data->verify || !driver_data->init ||
2766 !(driver_data->setpolicy || driver_data->target_index ||
2767 driver_data->target) ||
2768 (driver_data->setpolicy && (driver_data->target_index ||
2769 driver_data->target)) ||
2770 (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2771 (!driver_data->online != !driver_data->offline))
2774 pr_debug("trying to register driver %s\n", driver_data->name);
2776 /* Protect against concurrent CPU online/offline. */
2779 write_lock_irqsave(&cpufreq_driver_lock, flags);
2780 if (cpufreq_driver) {
2781 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2785 cpufreq_driver = driver_data;
2786 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2789 * Mark support for the scheduler's frequency invariance engine for
2790 * drivers that implement target(), target_index() or fast_switch().
2792 if (!cpufreq_driver->setpolicy) {
2793 static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
2794 pr_debug("supports frequency invariance");
2797 if (driver_data->setpolicy)
2798 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2800 if (cpufreq_boost_supported()) {
2801 ret = create_boost_sysfs_file();
2803 goto err_null_driver;
2806 ret = subsys_interface_register(&cpufreq_interface);
2808 goto err_boost_unreg;
2810 if (unlikely(list_empty(&cpufreq_policy_list))) {
2811 /* if all ->init() calls failed, unregister */
2813 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2818 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2820 cpuhp_cpufreq_online,
2821 cpuhp_cpufreq_offline);
2827 pr_debug("driver %s up and running\n", driver_data->name);
2831 subsys_interface_unregister(&cpufreq_interface);
2833 remove_boost_sysfs_file();
2835 write_lock_irqsave(&cpufreq_driver_lock, flags);
2836 cpufreq_driver = NULL;
2837 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2842 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2845 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2847 * Unregister the current CPUFreq driver. Only call this if you have
2848 * the right to do so, i.e. if you have succeeded in initialising before!
2849 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2850 * currently not initialised.
2852 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2854 unsigned long flags;
2856 if (!cpufreq_driver || (driver != cpufreq_driver))
2859 pr_debug("unregistering driver %s\n", driver->name);
2861 /* Protect against concurrent cpu hotplug */
2863 subsys_interface_unregister(&cpufreq_interface);
2864 remove_boost_sysfs_file();
2865 static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
2866 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2868 write_lock_irqsave(&cpufreq_driver_lock, flags);
2870 cpufreq_driver = NULL;
2872 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2877 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2879 static int __init cpufreq_core_init(void)
2881 struct cpufreq_governor *gov = cpufreq_default_governor();
2883 if (cpufreq_disabled())
2886 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2887 BUG_ON(!cpufreq_global_kobject);
2889 if (!strlen(default_governor))
2890 strncpy(default_governor, gov->name, CPUFREQ_NAME_LEN);
2894 module_param(off, int, 0444);
2895 module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
2896 core_initcall(cpufreq_core_init);