Linux 4.19.133
[linux/fpc-iii.git] / drivers / cpufreq / cpufreq.c
blobe35c397b1259fdb994fc3f1584df3adf923cee92
1 /*
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)
59 /**
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);
84 /**
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)
97 return off;
99 void disable_cpufreq(void)
101 off = 1;
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 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
113 if (have_governor_per_policy())
114 return &policy->kobj;
115 else
116 return cpufreq_global_kobject;
118 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
120 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
122 u64 idle_time;
123 u64 cur_wall_time;
124 u64 busy_time;
126 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
128 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
129 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
130 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
131 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
132 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
133 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
135 idle_time = cur_wall_time - busy_time;
136 if (wall)
137 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
139 return div_u64(idle_time, NSEC_PER_USEC);
142 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
144 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
146 if (idle_time == -1ULL)
147 return get_cpu_idle_time_jiffy(cpu, wall);
148 else if (!io_busy)
149 idle_time += get_cpu_iowait_time_us(cpu, wall);
151 return idle_time;
153 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
155 __weak void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
156 unsigned long max_freq)
159 EXPORT_SYMBOL_GPL(arch_set_freq_scale);
162 * This is a generic cpufreq init() routine which can be used by cpufreq
163 * drivers of SMP systems. It will do following:
164 * - validate & show freq table passed
165 * - set policies transition latency
166 * - policy->cpus with all possible CPUs
168 int cpufreq_generic_init(struct cpufreq_policy *policy,
169 struct cpufreq_frequency_table *table,
170 unsigned int transition_latency)
172 policy->freq_table = table;
173 policy->cpuinfo.transition_latency = transition_latency;
176 * The driver only supports the SMP configuration where all processors
177 * share the clock and voltage and clock.
179 cpumask_setall(policy->cpus);
181 return 0;
183 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
185 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
187 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
189 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
191 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
193 unsigned int cpufreq_generic_get(unsigned int cpu)
195 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
197 if (!policy || IS_ERR(policy->clk)) {
198 pr_err("%s: No %s associated to cpu: %d\n",
199 __func__, policy ? "clk" : "policy", cpu);
200 return 0;
203 return clk_get_rate(policy->clk) / 1000;
205 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
208 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
210 * @cpu: cpu to find policy for.
212 * This returns policy for 'cpu', returns NULL if it doesn't exist.
213 * It also increments the kobject reference count to mark it busy and so would
214 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
215 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
216 * freed as that depends on the kobj count.
218 * Return: A valid policy on success, otherwise NULL on failure.
220 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
222 struct cpufreq_policy *policy = NULL;
223 unsigned long flags;
225 if (WARN_ON(cpu >= nr_cpu_ids))
226 return NULL;
228 /* get the cpufreq driver */
229 read_lock_irqsave(&cpufreq_driver_lock, flags);
231 if (cpufreq_driver) {
232 /* get the CPU */
233 policy = cpufreq_cpu_get_raw(cpu);
234 if (policy)
235 kobject_get(&policy->kobj);
238 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
240 return policy;
242 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
245 * cpufreq_cpu_put: Decrements the usage count of a policy
247 * @policy: policy earlier returned by cpufreq_cpu_get().
249 * This decrements the kobject reference count incremented earlier by calling
250 * cpufreq_cpu_get().
252 void cpufreq_cpu_put(struct cpufreq_policy *policy)
254 kobject_put(&policy->kobj);
256 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
258 /*********************************************************************
259 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
260 *********************************************************************/
263 * adjust_jiffies - adjust the system "loops_per_jiffy"
265 * This function alters the system "loops_per_jiffy" for the clock
266 * speed change. Note that loops_per_jiffy cannot be updated on SMP
267 * systems as each CPU might be scaled differently. So, use the arch
268 * per-CPU loops_per_jiffy value wherever possible.
270 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
272 #ifndef CONFIG_SMP
273 static unsigned long l_p_j_ref;
274 static unsigned int l_p_j_ref_freq;
276 if (ci->flags & CPUFREQ_CONST_LOOPS)
277 return;
279 if (!l_p_j_ref_freq) {
280 l_p_j_ref = loops_per_jiffy;
281 l_p_j_ref_freq = ci->old;
282 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
283 l_p_j_ref, l_p_j_ref_freq);
285 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
286 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
287 ci->new);
288 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
289 loops_per_jiffy, ci->new);
291 #endif
295 * cpufreq_notify_transition - Notify frequency transition and adjust_jiffies.
296 * @policy: cpufreq policy to enable fast frequency switching for.
297 * @freqs: contain details of the frequency update.
298 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
300 * This function calls the transition notifiers and the "adjust_jiffies"
301 * function. It is called twice on all CPU frequency changes that have
302 * external effects.
304 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
305 struct cpufreq_freqs *freqs,
306 unsigned int state)
308 BUG_ON(irqs_disabled());
310 if (cpufreq_disabled())
311 return;
313 freqs->flags = cpufreq_driver->flags;
314 pr_debug("notification %u of frequency transition to %u kHz\n",
315 state, freqs->new);
317 switch (state) {
318 case CPUFREQ_PRECHANGE:
320 * Detect if the driver reported a value as "old frequency"
321 * which is not equal to what the cpufreq core thinks is
322 * "old frequency".
324 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
325 if (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;
332 for_each_cpu(freqs->cpu, policy->cpus) {
333 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
334 CPUFREQ_PRECHANGE, freqs);
337 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
338 break;
340 case CPUFREQ_POSTCHANGE:
341 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
342 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
343 cpumask_pr_args(policy->cpus));
345 for_each_cpu(freqs->cpu, policy->cpus) {
346 trace_cpu_frequency(freqs->new, freqs->cpu);
347 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
348 CPUFREQ_POSTCHANGE, freqs);
351 cpufreq_stats_record_transition(policy, freqs->new);
352 policy->cur = freqs->new;
356 /* Do post notifications when there are chances that transition has failed */
357 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
358 struct cpufreq_freqs *freqs, int transition_failed)
360 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
361 if (!transition_failed)
362 return;
364 swap(freqs->old, freqs->new);
365 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
366 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
369 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
370 struct cpufreq_freqs *freqs)
374 * Catch double invocations of _begin() which lead to self-deadlock.
375 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
376 * doesn't invoke _begin() on their behalf, and hence the chances of
377 * double invocations are very low. Moreover, there are scenarios
378 * where these checks can emit false-positive warnings in these
379 * drivers; so we avoid that by skipping them altogether.
381 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
382 && current == policy->transition_task);
384 wait:
385 wait_event(policy->transition_wait, !policy->transition_ongoing);
387 spin_lock(&policy->transition_lock);
389 if (unlikely(policy->transition_ongoing)) {
390 spin_unlock(&policy->transition_lock);
391 goto wait;
394 policy->transition_ongoing = true;
395 policy->transition_task = current;
397 spin_unlock(&policy->transition_lock);
399 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
401 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
403 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
404 struct cpufreq_freqs *freqs, int transition_failed)
406 if (unlikely(WARN_ON(!policy->transition_ongoing)))
407 return;
409 cpufreq_notify_post_transition(policy, freqs, transition_failed);
411 policy->transition_ongoing = false;
412 policy->transition_task = NULL;
414 wake_up(&policy->transition_wait);
416 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
419 * Fast frequency switching status count. Positive means "enabled", negative
420 * means "disabled" and 0 means "not decided yet".
422 static int cpufreq_fast_switch_count;
423 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
425 static void cpufreq_list_transition_notifiers(void)
427 struct notifier_block *nb;
429 pr_info("Registered transition notifiers:\n");
431 mutex_lock(&cpufreq_transition_notifier_list.mutex);
433 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
434 pr_info("%pF\n", nb->notifier_call);
436 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
440 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
441 * @policy: cpufreq policy to enable fast frequency switching for.
443 * Try to enable fast frequency switching for @policy.
445 * The attempt will fail if there is at least one transition notifier registered
446 * at this point, as fast frequency switching is quite fundamentally at odds
447 * with transition notifiers. Thus if successful, it will make registration of
448 * transition notifiers fail going forward.
450 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
452 lockdep_assert_held(&policy->rwsem);
454 if (!policy->fast_switch_possible)
455 return;
457 mutex_lock(&cpufreq_fast_switch_lock);
458 if (cpufreq_fast_switch_count >= 0) {
459 cpufreq_fast_switch_count++;
460 policy->fast_switch_enabled = true;
461 } else {
462 pr_warn("CPU%u: Fast frequency switching not enabled\n",
463 policy->cpu);
464 cpufreq_list_transition_notifiers();
466 mutex_unlock(&cpufreq_fast_switch_lock);
468 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
471 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
472 * @policy: cpufreq policy to disable fast frequency switching for.
474 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
476 mutex_lock(&cpufreq_fast_switch_lock);
477 if (policy->fast_switch_enabled) {
478 policy->fast_switch_enabled = false;
479 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
480 cpufreq_fast_switch_count--;
482 mutex_unlock(&cpufreq_fast_switch_lock);
484 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
487 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
488 * one.
489 * @target_freq: target frequency to resolve.
491 * The target to driver frequency mapping is cached in the policy.
493 * Return: Lowest driver-supported frequency greater than or equal to the
494 * given target_freq, subject to policy (min/max) and driver limitations.
496 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
497 unsigned int target_freq)
499 target_freq = clamp_val(target_freq, policy->min, policy->max);
500 policy->cached_target_freq = target_freq;
502 if (cpufreq_driver->target_index) {
503 int idx;
505 idx = cpufreq_frequency_table_target(policy, target_freq,
506 CPUFREQ_RELATION_L);
507 policy->cached_resolved_idx = idx;
508 return policy->freq_table[idx].frequency;
511 if (cpufreq_driver->resolve_freq)
512 return cpufreq_driver->resolve_freq(policy, target_freq);
514 return target_freq;
516 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
518 unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
520 unsigned int latency;
522 if (policy->transition_delay_us)
523 return policy->transition_delay_us;
525 latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
526 if (latency) {
528 * For platforms that can change the frequency very fast (< 10
529 * us), the above formula gives a decent transition delay. But
530 * for platforms where transition_latency is in milliseconds, it
531 * ends up giving unrealistic values.
533 * Cap the default transition delay to 10 ms, which seems to be
534 * a reasonable amount of time after which we should reevaluate
535 * the frequency.
537 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
540 return LATENCY_MULTIPLIER;
542 EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
544 /*********************************************************************
545 * SYSFS INTERFACE *
546 *********************************************************************/
547 static ssize_t show_boost(struct kobject *kobj,
548 struct kobj_attribute *attr, char *buf)
550 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
553 static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
554 const char *buf, size_t count)
556 int ret, enable;
558 ret = sscanf(buf, "%d", &enable);
559 if (ret != 1 || enable < 0 || enable > 1)
560 return -EINVAL;
562 if (cpufreq_boost_trigger_state(enable)) {
563 pr_err("%s: Cannot %s BOOST!\n",
564 __func__, enable ? "enable" : "disable");
565 return -EINVAL;
568 pr_debug("%s: cpufreq BOOST %s\n",
569 __func__, enable ? "enabled" : "disabled");
571 return count;
573 define_one_global_rw(boost);
575 static struct cpufreq_governor *find_governor(const char *str_governor)
577 struct cpufreq_governor *t;
579 for_each_governor(t)
580 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
581 return t;
583 return NULL;
587 * cpufreq_parse_governor - parse a governor string
589 static int cpufreq_parse_governor(char *str_governor,
590 struct cpufreq_policy *policy)
592 if (cpufreq_driver->setpolicy) {
593 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
594 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
595 return 0;
598 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
599 policy->policy = CPUFREQ_POLICY_POWERSAVE;
600 return 0;
602 } else {
603 struct cpufreq_governor *t;
605 mutex_lock(&cpufreq_governor_mutex);
607 t = find_governor(str_governor);
608 if (!t) {
609 int ret;
611 mutex_unlock(&cpufreq_governor_mutex);
613 ret = request_module("cpufreq_%s", str_governor);
614 if (ret)
615 return -EINVAL;
617 mutex_lock(&cpufreq_governor_mutex);
619 t = find_governor(str_governor);
621 if (t && !try_module_get(t->owner))
622 t = NULL;
624 mutex_unlock(&cpufreq_governor_mutex);
626 if (t) {
627 policy->governor = t;
628 return 0;
632 return -EINVAL;
636 * cpufreq_per_cpu_attr_read() / show_##file_name() -
637 * print out cpufreq information
639 * Write out information from cpufreq_driver->policy[cpu]; object must be
640 * "unsigned int".
643 #define show_one(file_name, object) \
644 static ssize_t show_##file_name \
645 (struct cpufreq_policy *policy, char *buf) \
647 return sprintf(buf, "%u\n", policy->object); \
650 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
651 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
652 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
653 show_one(scaling_min_freq, min);
654 show_one(scaling_max_freq, max);
656 __weak unsigned int arch_freq_get_on_cpu(int cpu)
658 return 0;
661 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
663 ssize_t ret;
664 unsigned int freq;
666 freq = arch_freq_get_on_cpu(policy->cpu);
667 if (freq)
668 ret = sprintf(buf, "%u\n", freq);
669 else if (cpufreq_driver && cpufreq_driver->setpolicy &&
670 cpufreq_driver->get)
671 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
672 else
673 ret = sprintf(buf, "%u\n", policy->cur);
674 return ret;
677 static int cpufreq_set_policy(struct cpufreq_policy *policy,
678 struct cpufreq_policy *new_policy);
681 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
683 #define store_one(file_name, object) \
684 static ssize_t store_##file_name \
685 (struct cpufreq_policy *policy, const char *buf, size_t count) \
687 int ret, temp; \
688 struct cpufreq_policy new_policy; \
690 memcpy(&new_policy, policy, sizeof(*policy)); \
691 new_policy.min = policy->user_policy.min; \
692 new_policy.max = policy->user_policy.max; \
694 ret = sscanf(buf, "%u", &new_policy.object); \
695 if (ret != 1) \
696 return -EINVAL; \
698 temp = new_policy.object; \
699 ret = cpufreq_set_policy(policy, &new_policy); \
700 if (!ret) \
701 policy->user_policy.object = temp; \
703 return ret ? ret : count; \
706 store_one(scaling_min_freq, min);
707 store_one(scaling_max_freq, max);
710 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
712 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
713 char *buf)
715 unsigned int cur_freq = __cpufreq_get(policy);
717 if (cur_freq)
718 return sprintf(buf, "%u\n", cur_freq);
720 return sprintf(buf, "<unknown>\n");
724 * show_scaling_governor - show the current policy for the specified CPU
726 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
728 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
729 return sprintf(buf, "powersave\n");
730 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
731 return sprintf(buf, "performance\n");
732 else if (policy->governor)
733 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
734 policy->governor->name);
735 return -EINVAL;
739 * store_scaling_governor - store policy for the specified CPU
741 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
742 const char *buf, size_t count)
744 int ret;
745 char str_governor[16];
746 struct cpufreq_policy new_policy;
748 memcpy(&new_policy, policy, sizeof(*policy));
750 ret = sscanf(buf, "%15s", str_governor);
751 if (ret != 1)
752 return -EINVAL;
754 if (cpufreq_parse_governor(str_governor, &new_policy))
755 return -EINVAL;
757 ret = cpufreq_set_policy(policy, &new_policy);
759 if (new_policy.governor)
760 module_put(new_policy.governor->owner);
762 return ret ? ret : count;
766 * show_scaling_driver - show the cpufreq driver currently loaded
768 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
770 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
774 * show_scaling_available_governors - show the available CPUfreq governors
776 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
777 char *buf)
779 ssize_t i = 0;
780 struct cpufreq_governor *t;
782 if (!has_target()) {
783 i += sprintf(buf, "performance powersave");
784 goto out;
787 for_each_governor(t) {
788 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
789 - (CPUFREQ_NAME_LEN + 2)))
790 goto out;
791 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
793 out:
794 i += sprintf(&buf[i], "\n");
795 return i;
798 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
800 ssize_t i = 0;
801 unsigned int cpu;
803 for_each_cpu(cpu, mask) {
804 if (i)
805 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
806 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
807 if (i >= (PAGE_SIZE - 5))
808 break;
810 i += sprintf(&buf[i], "\n");
811 return i;
813 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
816 * show_related_cpus - show the CPUs affected by each transition even if
817 * hw coordination is in use
819 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
821 return cpufreq_show_cpus(policy->related_cpus, buf);
825 * show_affected_cpus - show the CPUs affected by each transition
827 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
829 return cpufreq_show_cpus(policy->cpus, buf);
832 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
833 const char *buf, size_t count)
835 unsigned int freq = 0;
836 unsigned int ret;
838 if (!policy->governor || !policy->governor->store_setspeed)
839 return -EINVAL;
841 ret = sscanf(buf, "%u", &freq);
842 if (ret != 1)
843 return -EINVAL;
845 policy->governor->store_setspeed(policy, freq);
847 return count;
850 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
852 if (!policy->governor || !policy->governor->show_setspeed)
853 return sprintf(buf, "<unsupported>\n");
855 return policy->governor->show_setspeed(policy, buf);
859 * show_bios_limit - show the current cpufreq HW/BIOS limitation
861 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
863 unsigned int limit;
864 int ret;
865 if (cpufreq_driver->bios_limit) {
866 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
867 if (!ret)
868 return sprintf(buf, "%u\n", limit);
870 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
873 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
874 cpufreq_freq_attr_ro(cpuinfo_min_freq);
875 cpufreq_freq_attr_ro(cpuinfo_max_freq);
876 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
877 cpufreq_freq_attr_ro(scaling_available_governors);
878 cpufreq_freq_attr_ro(scaling_driver);
879 cpufreq_freq_attr_ro(scaling_cur_freq);
880 cpufreq_freq_attr_ro(bios_limit);
881 cpufreq_freq_attr_ro(related_cpus);
882 cpufreq_freq_attr_ro(affected_cpus);
883 cpufreq_freq_attr_rw(scaling_min_freq);
884 cpufreq_freq_attr_rw(scaling_max_freq);
885 cpufreq_freq_attr_rw(scaling_governor);
886 cpufreq_freq_attr_rw(scaling_setspeed);
888 static struct attribute *default_attrs[] = {
889 &cpuinfo_min_freq.attr,
890 &cpuinfo_max_freq.attr,
891 &cpuinfo_transition_latency.attr,
892 &scaling_min_freq.attr,
893 &scaling_max_freq.attr,
894 &affected_cpus.attr,
895 &related_cpus.attr,
896 &scaling_governor.attr,
897 &scaling_driver.attr,
898 &scaling_available_governors.attr,
899 &scaling_setspeed.attr,
900 NULL
903 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
904 #define to_attr(a) container_of(a, struct freq_attr, attr)
906 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
908 struct cpufreq_policy *policy = to_policy(kobj);
909 struct freq_attr *fattr = to_attr(attr);
910 ssize_t ret;
912 if (!fattr->show)
913 return -EIO;
915 down_read(&policy->rwsem);
916 ret = fattr->show(policy, buf);
917 up_read(&policy->rwsem);
919 return ret;
922 static ssize_t store(struct kobject *kobj, struct attribute *attr,
923 const char *buf, size_t count)
925 struct cpufreq_policy *policy = to_policy(kobj);
926 struct freq_attr *fattr = to_attr(attr);
927 ssize_t ret = -EINVAL;
929 if (!fattr->store)
930 return -EIO;
933 * cpus_read_trylock() is used here to work around a circular lock
934 * dependency problem with respect to the cpufreq_register_driver().
936 if (!cpus_read_trylock())
937 return -EBUSY;
939 if (cpu_online(policy->cpu)) {
940 down_write(&policy->rwsem);
941 ret = fattr->store(policy, buf, count);
942 up_write(&policy->rwsem);
945 cpus_read_unlock();
947 return ret;
950 static void cpufreq_sysfs_release(struct kobject *kobj)
952 struct cpufreq_policy *policy = to_policy(kobj);
953 pr_debug("last reference is dropped\n");
954 complete(&policy->kobj_unregister);
957 static const struct sysfs_ops sysfs_ops = {
958 .show = show,
959 .store = store,
962 static struct kobj_type ktype_cpufreq = {
963 .sysfs_ops = &sysfs_ops,
964 .default_attrs = default_attrs,
965 .release = cpufreq_sysfs_release,
968 static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
970 struct device *dev = get_cpu_device(cpu);
972 if (!dev)
973 return;
975 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
976 return;
978 dev_dbg(dev, "%s: Adding symlink\n", __func__);
979 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
980 dev_err(dev, "cpufreq symlink creation failed\n");
983 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
984 struct device *dev)
986 dev_dbg(dev, "%s: Removing symlink\n", __func__);
987 sysfs_remove_link(&dev->kobj, "cpufreq");
990 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
992 struct freq_attr **drv_attr;
993 int ret = 0;
995 /* set up files for this cpu device */
996 drv_attr = cpufreq_driver->attr;
997 while (drv_attr && *drv_attr) {
998 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
999 if (ret)
1000 return ret;
1001 drv_attr++;
1003 if (cpufreq_driver->get) {
1004 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1005 if (ret)
1006 return ret;
1009 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1010 if (ret)
1011 return ret;
1013 if (cpufreq_driver->bios_limit) {
1014 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1015 if (ret)
1016 return ret;
1019 return 0;
1022 __weak struct cpufreq_governor *cpufreq_default_governor(void)
1024 return NULL;
1027 static int cpufreq_init_policy(struct cpufreq_policy *policy)
1029 struct cpufreq_governor *gov = NULL;
1030 struct cpufreq_policy new_policy;
1032 memcpy(&new_policy, policy, sizeof(*policy));
1034 /* Update governor of new_policy to the governor used before hotplug */
1035 gov = find_governor(policy->last_governor);
1036 if (gov) {
1037 pr_debug("Restoring governor %s for cpu %d\n",
1038 policy->governor->name, policy->cpu);
1039 } else {
1040 gov = cpufreq_default_governor();
1041 if (!gov)
1042 return -ENODATA;
1045 new_policy.governor = gov;
1047 /* Use the default policy if there is no last_policy. */
1048 if (cpufreq_driver->setpolicy) {
1049 if (policy->last_policy)
1050 new_policy.policy = policy->last_policy;
1051 else
1052 cpufreq_parse_governor(gov->name, &new_policy);
1054 /* set default policy */
1055 return cpufreq_set_policy(policy, &new_policy);
1058 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1060 int ret = 0;
1062 /* Has this CPU been taken care of already? */
1063 if (cpumask_test_cpu(cpu, policy->cpus))
1064 return 0;
1066 down_write(&policy->rwsem);
1067 if (has_target())
1068 cpufreq_stop_governor(policy);
1070 cpumask_set_cpu(cpu, policy->cpus);
1072 if (has_target()) {
1073 ret = cpufreq_start_governor(policy);
1074 if (ret)
1075 pr_err("%s: Failed to start governor\n", __func__);
1077 up_write(&policy->rwsem);
1078 return ret;
1081 static void handle_update(struct work_struct *work)
1083 struct cpufreq_policy *policy =
1084 container_of(work, struct cpufreq_policy, update);
1085 unsigned int cpu = policy->cpu;
1086 pr_debug("handle_update for cpu %u called\n", cpu);
1087 cpufreq_update_policy(cpu);
1090 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1092 struct cpufreq_policy *policy;
1093 int ret;
1095 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1096 if (!policy)
1097 return NULL;
1099 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1100 goto err_free_policy;
1102 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1103 goto err_free_cpumask;
1105 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1106 goto err_free_rcpumask;
1108 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1109 cpufreq_global_kobject, "policy%u", cpu);
1110 if (ret) {
1111 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1112 kobject_put(&policy->kobj);
1113 goto err_free_real_cpus;
1116 INIT_LIST_HEAD(&policy->policy_list);
1117 init_rwsem(&policy->rwsem);
1118 spin_lock_init(&policy->transition_lock);
1119 init_waitqueue_head(&policy->transition_wait);
1120 init_completion(&policy->kobj_unregister);
1121 INIT_WORK(&policy->update, handle_update);
1123 policy->cpu = cpu;
1124 return policy;
1126 err_free_real_cpus:
1127 free_cpumask_var(policy->real_cpus);
1128 err_free_rcpumask:
1129 free_cpumask_var(policy->related_cpus);
1130 err_free_cpumask:
1131 free_cpumask_var(policy->cpus);
1132 err_free_policy:
1133 kfree(policy);
1135 return NULL;
1138 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1140 struct kobject *kobj;
1141 struct completion *cmp;
1143 down_write(&policy->rwsem);
1144 cpufreq_stats_free_table(policy);
1145 kobj = &policy->kobj;
1146 cmp = &policy->kobj_unregister;
1147 up_write(&policy->rwsem);
1148 kobject_put(kobj);
1151 * We need to make sure that the underlying kobj is
1152 * actually not referenced anymore by anybody before we
1153 * proceed with unloading.
1155 pr_debug("waiting for dropping of refcount\n");
1156 wait_for_completion(cmp);
1157 pr_debug("wait complete\n");
1160 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1162 unsigned long flags;
1163 int cpu;
1165 /* Remove policy from list */
1166 write_lock_irqsave(&cpufreq_driver_lock, flags);
1167 list_del(&policy->policy_list);
1169 for_each_cpu(cpu, policy->related_cpus)
1170 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1171 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1173 cpufreq_policy_put_kobj(policy);
1174 free_cpumask_var(policy->real_cpus);
1175 free_cpumask_var(policy->related_cpus);
1176 free_cpumask_var(policy->cpus);
1177 kfree(policy);
1180 static int cpufreq_online(unsigned int cpu)
1182 struct cpufreq_policy *policy;
1183 bool new_policy;
1184 unsigned long flags;
1185 unsigned int j;
1186 int ret;
1188 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1190 /* Check if this CPU already has a policy to manage it */
1191 policy = per_cpu(cpufreq_cpu_data, cpu);
1192 if (policy) {
1193 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1194 if (!policy_is_inactive(policy))
1195 return cpufreq_add_policy_cpu(policy, cpu);
1197 /* This is the only online CPU for the policy. Start over. */
1198 new_policy = false;
1199 down_write(&policy->rwsem);
1200 policy->cpu = cpu;
1201 policy->governor = NULL;
1202 up_write(&policy->rwsem);
1203 } else {
1204 new_policy = true;
1205 policy = cpufreq_policy_alloc(cpu);
1206 if (!policy)
1207 return -ENOMEM;
1210 cpumask_copy(policy->cpus, cpumask_of(cpu));
1212 /* call driver. From then on the cpufreq must be able
1213 * to accept all calls to ->verify and ->setpolicy for this CPU
1215 ret = cpufreq_driver->init(policy);
1216 if (ret) {
1217 pr_debug("initialization failed\n");
1218 goto out_free_policy;
1221 ret = cpufreq_table_validate_and_sort(policy);
1222 if (ret)
1223 goto out_exit_policy;
1225 down_write(&policy->rwsem);
1227 if (new_policy) {
1228 /* related_cpus should at least include policy->cpus. */
1229 cpumask_copy(policy->related_cpus, policy->cpus);
1233 * affected cpus must always be the one, which are online. We aren't
1234 * managing offline cpus here.
1236 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1238 if (new_policy) {
1239 policy->user_policy.min = policy->min;
1240 policy->user_policy.max = policy->max;
1242 for_each_cpu(j, policy->related_cpus) {
1243 per_cpu(cpufreq_cpu_data, j) = policy;
1244 add_cpu_dev_symlink(policy, j);
1246 } else {
1247 policy->min = policy->user_policy.min;
1248 policy->max = policy->user_policy.max;
1251 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1252 policy->cur = cpufreq_driver->get(policy->cpu);
1253 if (!policy->cur) {
1254 pr_err("%s: ->get() failed\n", __func__);
1255 goto out_destroy_policy;
1260 * Sometimes boot loaders set CPU frequency to a value outside of
1261 * frequency table present with cpufreq core. In such cases CPU might be
1262 * unstable if it has to run on that frequency for long duration of time
1263 * and so its better to set it to a frequency which is specified in
1264 * freq-table. This also makes cpufreq stats inconsistent as
1265 * cpufreq-stats would fail to register because current frequency of CPU
1266 * isn't found in freq-table.
1268 * Because we don't want this change to effect boot process badly, we go
1269 * for the next freq which is >= policy->cur ('cur' must be set by now,
1270 * otherwise we will end up setting freq to lowest of the table as 'cur'
1271 * is initialized to zero).
1273 * We are passing target-freq as "policy->cur - 1" otherwise
1274 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1275 * equal to target-freq.
1277 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1278 && has_target()) {
1279 /* Are we running at unknown frequency ? */
1280 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1281 if (ret == -EINVAL) {
1282 /* Warn user and fix it */
1283 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1284 __func__, policy->cpu, policy->cur);
1285 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1286 CPUFREQ_RELATION_L);
1289 * Reaching here after boot in a few seconds may not
1290 * mean that system will remain stable at "unknown"
1291 * frequency for longer duration. Hence, a BUG_ON().
1293 BUG_ON(ret);
1294 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1295 __func__, policy->cpu, policy->cur);
1299 if (new_policy) {
1300 ret = cpufreq_add_dev_interface(policy);
1301 if (ret)
1302 goto out_destroy_policy;
1304 cpufreq_stats_create_table(policy);
1306 write_lock_irqsave(&cpufreq_driver_lock, flags);
1307 list_add(&policy->policy_list, &cpufreq_policy_list);
1308 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1311 ret = cpufreq_init_policy(policy);
1312 if (ret) {
1313 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1314 __func__, cpu, ret);
1315 /* cpufreq_policy_free() will notify based on this */
1316 new_policy = false;
1317 goto out_destroy_policy;
1320 up_write(&policy->rwsem);
1322 kobject_uevent(&policy->kobj, KOBJ_ADD);
1324 /* Callback for handling stuff after policy is ready */
1325 if (cpufreq_driver->ready)
1326 cpufreq_driver->ready(policy);
1328 pr_debug("initialization complete\n");
1330 return 0;
1332 out_destroy_policy:
1333 for_each_cpu(j, policy->real_cpus)
1334 remove_cpu_dev_symlink(policy, get_cpu_device(j));
1336 up_write(&policy->rwsem);
1338 out_exit_policy:
1339 if (cpufreq_driver->exit)
1340 cpufreq_driver->exit(policy);
1342 out_free_policy:
1343 cpufreq_policy_free(policy);
1344 return ret;
1348 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1349 * @dev: CPU device.
1350 * @sif: Subsystem interface structure pointer (not used)
1352 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1354 struct cpufreq_policy *policy;
1355 unsigned cpu = dev->id;
1356 int ret;
1358 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1360 if (cpu_online(cpu)) {
1361 ret = cpufreq_online(cpu);
1362 if (ret)
1363 return ret;
1366 /* Create sysfs link on CPU registration */
1367 policy = per_cpu(cpufreq_cpu_data, cpu);
1368 if (policy)
1369 add_cpu_dev_symlink(policy, cpu);
1371 return 0;
1374 static int cpufreq_offline(unsigned int cpu)
1376 struct cpufreq_policy *policy;
1377 int ret;
1379 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1381 policy = cpufreq_cpu_get_raw(cpu);
1382 if (!policy) {
1383 pr_debug("%s: No cpu_data found\n", __func__);
1384 return 0;
1387 down_write(&policy->rwsem);
1388 if (has_target())
1389 cpufreq_stop_governor(policy);
1391 cpumask_clear_cpu(cpu, policy->cpus);
1393 if (policy_is_inactive(policy)) {
1394 if (has_target())
1395 strncpy(policy->last_governor, policy->governor->name,
1396 CPUFREQ_NAME_LEN);
1397 else
1398 policy->last_policy = policy->policy;
1399 } else if (cpu == policy->cpu) {
1400 /* Nominate new CPU */
1401 policy->cpu = cpumask_any(policy->cpus);
1404 /* Start governor again for active policy */
1405 if (!policy_is_inactive(policy)) {
1406 if (has_target()) {
1407 ret = cpufreq_start_governor(policy);
1408 if (ret)
1409 pr_err("%s: Failed to start governor\n", __func__);
1412 goto unlock;
1415 if (cpufreq_driver->stop_cpu)
1416 cpufreq_driver->stop_cpu(policy);
1418 if (has_target())
1419 cpufreq_exit_governor(policy);
1422 * Perform the ->exit() even during light-weight tear-down,
1423 * since this is a core component, and is essential for the
1424 * subsequent light-weight ->init() to succeed.
1426 if (cpufreq_driver->exit) {
1427 cpufreq_driver->exit(policy);
1428 policy->freq_table = NULL;
1431 unlock:
1432 up_write(&policy->rwsem);
1433 return 0;
1437 * cpufreq_remove_dev - remove a CPU device
1439 * Removes the cpufreq interface for a CPU device.
1441 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1443 unsigned int cpu = dev->id;
1444 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1446 if (!policy)
1447 return;
1449 if (cpu_online(cpu))
1450 cpufreq_offline(cpu);
1452 cpumask_clear_cpu(cpu, policy->real_cpus);
1453 remove_cpu_dev_symlink(policy, dev);
1455 if (cpumask_empty(policy->real_cpus))
1456 cpufreq_policy_free(policy);
1460 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1461 * in deep trouble.
1462 * @policy: policy managing CPUs
1463 * @new_freq: CPU frequency the CPU actually runs at
1465 * We adjust to current frequency first, and need to clean up later.
1466 * So either call to cpufreq_update_policy() or schedule handle_update()).
1468 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1469 unsigned int new_freq)
1471 struct cpufreq_freqs freqs;
1473 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1474 policy->cur, new_freq);
1476 freqs.old = policy->cur;
1477 freqs.new = new_freq;
1479 cpufreq_freq_transition_begin(policy, &freqs);
1480 cpufreq_freq_transition_end(policy, &freqs, 0);
1484 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1485 * @cpu: CPU number
1487 * This is the last known freq, without actually getting it from the driver.
1488 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1490 unsigned int cpufreq_quick_get(unsigned int cpu)
1492 struct cpufreq_policy *policy;
1493 unsigned int ret_freq = 0;
1494 unsigned long flags;
1496 read_lock_irqsave(&cpufreq_driver_lock, flags);
1498 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1499 ret_freq = cpufreq_driver->get(cpu);
1500 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1501 return ret_freq;
1504 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1506 policy = cpufreq_cpu_get(cpu);
1507 if (policy) {
1508 ret_freq = policy->cur;
1509 cpufreq_cpu_put(policy);
1512 return ret_freq;
1514 EXPORT_SYMBOL(cpufreq_quick_get);
1517 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1518 * @cpu: CPU number
1520 * Just return the max possible frequency for a given CPU.
1522 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1524 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1525 unsigned int ret_freq = 0;
1527 if (policy) {
1528 ret_freq = policy->max;
1529 cpufreq_cpu_put(policy);
1532 return ret_freq;
1534 EXPORT_SYMBOL(cpufreq_quick_get_max);
1536 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1538 unsigned int ret_freq = 0;
1540 if (unlikely(policy_is_inactive(policy)) || !cpufreq_driver->get)
1541 return ret_freq;
1543 ret_freq = cpufreq_driver->get(policy->cpu);
1546 * If fast frequency switching is used with the given policy, the check
1547 * against policy->cur is pointless, so skip it in that case too.
1549 if (policy->fast_switch_enabled)
1550 return ret_freq;
1552 if (ret_freq && policy->cur &&
1553 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1554 /* verify no discrepancy between actual and
1555 saved value exists */
1556 if (unlikely(ret_freq != policy->cur)) {
1557 cpufreq_out_of_sync(policy, ret_freq);
1558 schedule_work(&policy->update);
1562 return ret_freq;
1566 * cpufreq_get - get the current CPU frequency (in kHz)
1567 * @cpu: CPU number
1569 * Get the CPU current (static) CPU frequency
1571 unsigned int cpufreq_get(unsigned int cpu)
1573 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1574 unsigned int ret_freq = 0;
1576 if (policy) {
1577 down_read(&policy->rwsem);
1578 ret_freq = __cpufreq_get(policy);
1579 up_read(&policy->rwsem);
1581 cpufreq_cpu_put(policy);
1584 return ret_freq;
1586 EXPORT_SYMBOL(cpufreq_get);
1588 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1590 unsigned int new_freq;
1592 new_freq = cpufreq_driver->get(policy->cpu);
1593 if (!new_freq)
1594 return 0;
1596 if (!policy->cur) {
1597 pr_debug("cpufreq: Driver did not initialize current freq\n");
1598 policy->cur = new_freq;
1599 } else if (policy->cur != new_freq && has_target()) {
1600 cpufreq_out_of_sync(policy, new_freq);
1603 return new_freq;
1606 static struct subsys_interface cpufreq_interface = {
1607 .name = "cpufreq",
1608 .subsys = &cpu_subsys,
1609 .add_dev = cpufreq_add_dev,
1610 .remove_dev = cpufreq_remove_dev,
1614 * In case platform wants some specific frequency to be configured
1615 * during suspend..
1617 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1619 int ret;
1621 if (!policy->suspend_freq) {
1622 pr_debug("%s: suspend_freq not defined\n", __func__);
1623 return 0;
1626 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1627 policy->suspend_freq);
1629 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1630 CPUFREQ_RELATION_H);
1631 if (ret)
1632 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1633 __func__, policy->suspend_freq, ret);
1635 return ret;
1637 EXPORT_SYMBOL(cpufreq_generic_suspend);
1640 * cpufreq_suspend() - Suspend CPUFreq governors
1642 * Called during system wide Suspend/Hibernate cycles for suspending governors
1643 * as some platforms can't change frequency after this point in suspend cycle.
1644 * Because some of the devices (like: i2c, regulators, etc) they use for
1645 * changing frequency are suspended quickly after this point.
1647 void cpufreq_suspend(void)
1649 struct cpufreq_policy *policy;
1651 if (!cpufreq_driver)
1652 return;
1654 if (!has_target() && !cpufreq_driver->suspend)
1655 goto suspend;
1657 pr_debug("%s: Suspending Governors\n", __func__);
1659 for_each_active_policy(policy) {
1660 if (has_target()) {
1661 down_write(&policy->rwsem);
1662 cpufreq_stop_governor(policy);
1663 up_write(&policy->rwsem);
1666 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1667 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1668 policy);
1671 suspend:
1672 cpufreq_suspended = true;
1676 * cpufreq_resume() - Resume CPUFreq governors
1678 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1679 * are suspended with cpufreq_suspend().
1681 void cpufreq_resume(void)
1683 struct cpufreq_policy *policy;
1684 int ret;
1686 if (!cpufreq_driver)
1687 return;
1689 if (unlikely(!cpufreq_suspended))
1690 return;
1692 cpufreq_suspended = false;
1694 if (!has_target() && !cpufreq_driver->resume)
1695 return;
1697 pr_debug("%s: Resuming Governors\n", __func__);
1699 for_each_active_policy(policy) {
1700 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1701 pr_err("%s: Failed to resume driver: %p\n", __func__,
1702 policy);
1703 } else if (has_target()) {
1704 down_write(&policy->rwsem);
1705 ret = cpufreq_start_governor(policy);
1706 up_write(&policy->rwsem);
1708 if (ret)
1709 pr_err("%s: Failed to start governor for policy: %p\n",
1710 __func__, policy);
1716 * cpufreq_get_current_driver - return current driver's name
1718 * Return the name string of the currently loaded cpufreq driver
1719 * or NULL, if none.
1721 const char *cpufreq_get_current_driver(void)
1723 if (cpufreq_driver)
1724 return cpufreq_driver->name;
1726 return NULL;
1728 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1731 * cpufreq_get_driver_data - return current driver data
1733 * Return the private data of the currently loaded cpufreq
1734 * driver, or NULL if no cpufreq driver is loaded.
1736 void *cpufreq_get_driver_data(void)
1738 if (cpufreq_driver)
1739 return cpufreq_driver->driver_data;
1741 return NULL;
1743 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1745 /*********************************************************************
1746 * NOTIFIER LISTS INTERFACE *
1747 *********************************************************************/
1750 * cpufreq_register_notifier - register a driver with cpufreq
1751 * @nb: notifier function to register
1752 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1754 * Add a driver to one of two lists: either a list of drivers that
1755 * are notified about clock rate changes (once before and once after
1756 * the transition), or a list of drivers that are notified about
1757 * changes in cpufreq policy.
1759 * This function may sleep, and has the same return conditions as
1760 * blocking_notifier_chain_register.
1762 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1764 int ret;
1766 if (cpufreq_disabled())
1767 return -EINVAL;
1769 switch (list) {
1770 case CPUFREQ_TRANSITION_NOTIFIER:
1771 mutex_lock(&cpufreq_fast_switch_lock);
1773 if (cpufreq_fast_switch_count > 0) {
1774 mutex_unlock(&cpufreq_fast_switch_lock);
1775 return -EBUSY;
1777 ret = srcu_notifier_chain_register(
1778 &cpufreq_transition_notifier_list, nb);
1779 if (!ret)
1780 cpufreq_fast_switch_count--;
1782 mutex_unlock(&cpufreq_fast_switch_lock);
1783 break;
1784 case CPUFREQ_POLICY_NOTIFIER:
1785 ret = blocking_notifier_chain_register(
1786 &cpufreq_policy_notifier_list, nb);
1787 break;
1788 default:
1789 ret = -EINVAL;
1792 return ret;
1794 EXPORT_SYMBOL(cpufreq_register_notifier);
1797 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1798 * @nb: notifier block to be unregistered
1799 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1801 * Remove a driver from the CPU frequency notifier list.
1803 * This function may sleep, and has the same return conditions as
1804 * blocking_notifier_chain_unregister.
1806 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1808 int ret;
1810 if (cpufreq_disabled())
1811 return -EINVAL;
1813 switch (list) {
1814 case CPUFREQ_TRANSITION_NOTIFIER:
1815 mutex_lock(&cpufreq_fast_switch_lock);
1817 ret = srcu_notifier_chain_unregister(
1818 &cpufreq_transition_notifier_list, nb);
1819 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1820 cpufreq_fast_switch_count++;
1822 mutex_unlock(&cpufreq_fast_switch_lock);
1823 break;
1824 case CPUFREQ_POLICY_NOTIFIER:
1825 ret = blocking_notifier_chain_unregister(
1826 &cpufreq_policy_notifier_list, nb);
1827 break;
1828 default:
1829 ret = -EINVAL;
1832 return ret;
1834 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1837 /*********************************************************************
1838 * GOVERNORS *
1839 *********************************************************************/
1842 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1843 * @policy: cpufreq policy to switch the frequency for.
1844 * @target_freq: New frequency to set (may be approximate).
1846 * Carry out a fast frequency switch without sleeping.
1848 * The driver's ->fast_switch() callback invoked by this function must be
1849 * suitable for being called from within RCU-sched read-side critical sections
1850 * and it is expected to select the minimum available frequency greater than or
1851 * equal to @target_freq (CPUFREQ_RELATION_L).
1853 * This function must not be called if policy->fast_switch_enabled is unset.
1855 * Governors calling this function must guarantee that it will never be invoked
1856 * twice in parallel for the same policy and that it will never be called in
1857 * parallel with either ->target() or ->target_index() for the same policy.
1859 * Returns the actual frequency set for the CPU.
1861 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
1862 * error condition, the hardware configuration must be preserved.
1864 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1865 unsigned int target_freq)
1867 target_freq = clamp_val(target_freq, policy->min, policy->max);
1869 return cpufreq_driver->fast_switch(policy, target_freq);
1871 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1873 /* Must set freqs->new to intermediate frequency */
1874 static int __target_intermediate(struct cpufreq_policy *policy,
1875 struct cpufreq_freqs *freqs, int index)
1877 int ret;
1879 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1881 /* We don't need to switch to intermediate freq */
1882 if (!freqs->new)
1883 return 0;
1885 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1886 __func__, policy->cpu, freqs->old, freqs->new);
1888 cpufreq_freq_transition_begin(policy, freqs);
1889 ret = cpufreq_driver->target_intermediate(policy, index);
1890 cpufreq_freq_transition_end(policy, freqs, ret);
1892 if (ret)
1893 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1894 __func__, ret);
1896 return ret;
1899 static int __target_index(struct cpufreq_policy *policy, int index)
1901 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1902 unsigned int intermediate_freq = 0;
1903 unsigned int newfreq = policy->freq_table[index].frequency;
1904 int retval = -EINVAL;
1905 bool notify;
1907 if (newfreq == policy->cur)
1908 return 0;
1910 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1911 if (notify) {
1912 /* Handle switching to intermediate frequency */
1913 if (cpufreq_driver->get_intermediate) {
1914 retval = __target_intermediate(policy, &freqs, index);
1915 if (retval)
1916 return retval;
1918 intermediate_freq = freqs.new;
1919 /* Set old freq to intermediate */
1920 if (intermediate_freq)
1921 freqs.old = freqs.new;
1924 freqs.new = newfreq;
1925 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1926 __func__, policy->cpu, freqs.old, freqs.new);
1928 cpufreq_freq_transition_begin(policy, &freqs);
1931 retval = cpufreq_driver->target_index(policy, index);
1932 if (retval)
1933 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1934 retval);
1936 if (notify) {
1937 cpufreq_freq_transition_end(policy, &freqs, retval);
1940 * Failed after setting to intermediate freq? Driver should have
1941 * reverted back to initial frequency and so should we. Check
1942 * here for intermediate_freq instead of get_intermediate, in
1943 * case we haven't switched to intermediate freq at all.
1945 if (unlikely(retval && intermediate_freq)) {
1946 freqs.old = intermediate_freq;
1947 freqs.new = policy->restore_freq;
1948 cpufreq_freq_transition_begin(policy, &freqs);
1949 cpufreq_freq_transition_end(policy, &freqs, 0);
1953 return retval;
1956 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1957 unsigned int target_freq,
1958 unsigned int relation)
1960 unsigned int old_target_freq = target_freq;
1961 int index;
1963 if (cpufreq_disabled())
1964 return -ENODEV;
1966 /* Make sure that target_freq is within supported range */
1967 target_freq = clamp_val(target_freq, policy->min, policy->max);
1969 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1970 policy->cpu, target_freq, relation, old_target_freq);
1973 * This might look like a redundant call as we are checking it again
1974 * after finding index. But it is left intentionally for cases where
1975 * exactly same freq is called again and so we can save on few function
1976 * calls.
1978 if (target_freq == policy->cur)
1979 return 0;
1981 /* Save last value to restore later on errors */
1982 policy->restore_freq = policy->cur;
1984 if (cpufreq_driver->target)
1985 return cpufreq_driver->target(policy, target_freq, relation);
1987 if (!cpufreq_driver->target_index)
1988 return -EINVAL;
1990 index = cpufreq_frequency_table_target(policy, target_freq, relation);
1992 return __target_index(policy, index);
1994 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1996 int cpufreq_driver_target(struct cpufreq_policy *policy,
1997 unsigned int target_freq,
1998 unsigned int relation)
2000 int ret = -EINVAL;
2002 down_write(&policy->rwsem);
2004 ret = __cpufreq_driver_target(policy, target_freq, relation);
2006 up_write(&policy->rwsem);
2008 return ret;
2010 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2012 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2014 return NULL;
2017 static int cpufreq_init_governor(struct cpufreq_policy *policy)
2019 int ret;
2021 /* Don't start any governor operations if we are entering suspend */
2022 if (cpufreq_suspended)
2023 return 0;
2025 * Governor might not be initiated here if ACPI _PPC changed
2026 * notification happened, so check it.
2028 if (!policy->governor)
2029 return -EINVAL;
2031 /* Platform doesn't want dynamic frequency switching ? */
2032 if (policy->governor->dynamic_switching &&
2033 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2034 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2036 if (gov) {
2037 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2038 policy->governor->name, gov->name);
2039 policy->governor = gov;
2040 } else {
2041 return -EINVAL;
2045 if (!try_module_get(policy->governor->owner))
2046 return -EINVAL;
2048 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2050 if (policy->governor->init) {
2051 ret = policy->governor->init(policy);
2052 if (ret) {
2053 module_put(policy->governor->owner);
2054 return ret;
2058 return 0;
2061 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2063 if (cpufreq_suspended || !policy->governor)
2064 return;
2066 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2068 if (policy->governor->exit)
2069 policy->governor->exit(policy);
2071 module_put(policy->governor->owner);
2074 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2076 int ret;
2078 if (cpufreq_suspended)
2079 return 0;
2081 if (!policy->governor)
2082 return -EINVAL;
2084 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2086 if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2087 cpufreq_update_current_freq(policy);
2089 if (policy->governor->start) {
2090 ret = policy->governor->start(policy);
2091 if (ret)
2092 return ret;
2095 if (policy->governor->limits)
2096 policy->governor->limits(policy);
2098 return 0;
2101 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2103 if (cpufreq_suspended || !policy->governor)
2104 return;
2106 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2108 if (policy->governor->stop)
2109 policy->governor->stop(policy);
2112 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2114 if (cpufreq_suspended || !policy->governor)
2115 return;
2117 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2119 if (policy->governor->limits)
2120 policy->governor->limits(policy);
2123 int cpufreq_register_governor(struct cpufreq_governor *governor)
2125 int err;
2127 if (!governor)
2128 return -EINVAL;
2130 if (cpufreq_disabled())
2131 return -ENODEV;
2133 mutex_lock(&cpufreq_governor_mutex);
2135 err = -EBUSY;
2136 if (!find_governor(governor->name)) {
2137 err = 0;
2138 list_add(&governor->governor_list, &cpufreq_governor_list);
2141 mutex_unlock(&cpufreq_governor_mutex);
2142 return err;
2144 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2146 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2148 struct cpufreq_policy *policy;
2149 unsigned long flags;
2151 if (!governor)
2152 return;
2154 if (cpufreq_disabled())
2155 return;
2157 /* clear last_governor for all inactive policies */
2158 read_lock_irqsave(&cpufreq_driver_lock, flags);
2159 for_each_inactive_policy(policy) {
2160 if (!strcmp(policy->last_governor, governor->name)) {
2161 policy->governor = NULL;
2162 strcpy(policy->last_governor, "\0");
2165 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2167 mutex_lock(&cpufreq_governor_mutex);
2168 list_del(&governor->governor_list);
2169 mutex_unlock(&cpufreq_governor_mutex);
2171 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2174 /*********************************************************************
2175 * POLICY INTERFACE *
2176 *********************************************************************/
2179 * cpufreq_get_policy - get the current cpufreq_policy
2180 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2181 * is written
2183 * Reads the current cpufreq policy.
2185 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2187 struct cpufreq_policy *cpu_policy;
2188 if (!policy)
2189 return -EINVAL;
2191 cpu_policy = cpufreq_cpu_get(cpu);
2192 if (!cpu_policy)
2193 return -EINVAL;
2195 memcpy(policy, cpu_policy, sizeof(*policy));
2197 cpufreq_cpu_put(cpu_policy);
2198 return 0;
2200 EXPORT_SYMBOL(cpufreq_get_policy);
2203 * policy : current policy.
2204 * new_policy: policy to be set.
2206 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2207 struct cpufreq_policy *new_policy)
2209 struct cpufreq_governor *old_gov;
2210 int ret;
2212 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2213 new_policy->cpu, new_policy->min, new_policy->max);
2215 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2218 * This check works well when we store new min/max freq attributes,
2219 * because new_policy is a copy of policy with one field updated.
2221 if (new_policy->min > new_policy->max)
2222 return -EINVAL;
2224 /* verify the cpu speed can be set within this limit */
2225 ret = cpufreq_driver->verify(new_policy);
2226 if (ret)
2227 return ret;
2229 /* adjust if necessary - all reasons */
2230 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2231 CPUFREQ_ADJUST, new_policy);
2234 * verify the cpu speed can be set within this limit, which might be
2235 * different to the first one
2237 ret = cpufreq_driver->verify(new_policy);
2238 if (ret)
2239 return ret;
2241 /* notification of the new policy */
2242 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2243 CPUFREQ_NOTIFY, new_policy);
2245 policy->min = new_policy->min;
2246 policy->max = new_policy->max;
2247 trace_cpu_frequency_limits(policy);
2249 policy->cached_target_freq = UINT_MAX;
2251 pr_debug("new min and max freqs are %u - %u kHz\n",
2252 policy->min, policy->max);
2254 if (cpufreq_driver->setpolicy) {
2255 policy->policy = new_policy->policy;
2256 pr_debug("setting range\n");
2257 return cpufreq_driver->setpolicy(new_policy);
2260 if (new_policy->governor == policy->governor) {
2261 pr_debug("cpufreq: governor limits update\n");
2262 cpufreq_governor_limits(policy);
2263 return 0;
2266 pr_debug("governor switch\n");
2268 /* save old, working values */
2269 old_gov = policy->governor;
2270 /* end old governor */
2271 if (old_gov) {
2272 cpufreq_stop_governor(policy);
2273 cpufreq_exit_governor(policy);
2276 /* start new governor */
2277 policy->governor = new_policy->governor;
2278 ret = cpufreq_init_governor(policy);
2279 if (!ret) {
2280 ret = cpufreq_start_governor(policy);
2281 if (!ret) {
2282 pr_debug("cpufreq: governor change\n");
2283 return 0;
2285 cpufreq_exit_governor(policy);
2288 /* new governor failed, so re-start old one */
2289 pr_debug("starting governor %s failed\n", policy->governor->name);
2290 if (old_gov) {
2291 policy->governor = old_gov;
2292 if (cpufreq_init_governor(policy))
2293 policy->governor = NULL;
2294 else
2295 cpufreq_start_governor(policy);
2298 return ret;
2302 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2303 * @cpu: CPU which shall be re-evaluated
2305 * Useful for policy notifiers which have different necessities
2306 * at different times.
2308 void cpufreq_update_policy(unsigned int cpu)
2310 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2311 struct cpufreq_policy new_policy;
2313 if (!policy)
2314 return;
2316 down_write(&policy->rwsem);
2318 if (policy_is_inactive(policy))
2319 goto unlock;
2321 pr_debug("updating policy for CPU %u\n", cpu);
2322 memcpy(&new_policy, policy, sizeof(*policy));
2323 new_policy.min = policy->user_policy.min;
2324 new_policy.max = policy->user_policy.max;
2327 * BIOS might change freq behind our back
2328 * -> ask driver for current freq and notify governors about a change
2330 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2331 if (cpufreq_suspended)
2332 goto unlock;
2334 new_policy.cur = cpufreq_update_current_freq(policy);
2335 if (WARN_ON(!new_policy.cur))
2336 goto unlock;
2339 cpufreq_set_policy(policy, &new_policy);
2341 unlock:
2342 up_write(&policy->rwsem);
2344 cpufreq_cpu_put(policy);
2346 EXPORT_SYMBOL(cpufreq_update_policy);
2348 /*********************************************************************
2349 * BOOST *
2350 *********************************************************************/
2351 static int cpufreq_boost_set_sw(int state)
2353 struct cpufreq_policy *policy;
2354 int ret = -EINVAL;
2356 for_each_active_policy(policy) {
2357 if (!policy->freq_table)
2358 continue;
2360 ret = cpufreq_frequency_table_cpuinfo(policy,
2361 policy->freq_table);
2362 if (ret) {
2363 pr_err("%s: Policy frequency update failed\n",
2364 __func__);
2365 break;
2368 down_write(&policy->rwsem);
2369 policy->user_policy.max = policy->max;
2370 cpufreq_governor_limits(policy);
2371 up_write(&policy->rwsem);
2374 return ret;
2377 int cpufreq_boost_trigger_state(int state)
2379 unsigned long flags;
2380 int ret = 0;
2382 if (cpufreq_driver->boost_enabled == state)
2383 return 0;
2385 write_lock_irqsave(&cpufreq_driver_lock, flags);
2386 cpufreq_driver->boost_enabled = state;
2387 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2389 ret = cpufreq_driver->set_boost(state);
2390 if (ret) {
2391 write_lock_irqsave(&cpufreq_driver_lock, flags);
2392 cpufreq_driver->boost_enabled = !state;
2393 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2395 pr_err("%s: Cannot %s BOOST\n",
2396 __func__, state ? "enable" : "disable");
2399 return ret;
2402 static bool cpufreq_boost_supported(void)
2404 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2407 static int create_boost_sysfs_file(void)
2409 int ret;
2411 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2412 if (ret)
2413 pr_err("%s: cannot register global BOOST sysfs file\n",
2414 __func__);
2416 return ret;
2419 static void remove_boost_sysfs_file(void)
2421 if (cpufreq_boost_supported())
2422 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2425 int cpufreq_enable_boost_support(void)
2427 if (!cpufreq_driver)
2428 return -EINVAL;
2430 if (cpufreq_boost_supported())
2431 return 0;
2433 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2435 /* This will get removed on driver unregister */
2436 return create_boost_sysfs_file();
2438 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2440 int cpufreq_boost_enabled(void)
2442 return cpufreq_driver->boost_enabled;
2444 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2446 /*********************************************************************
2447 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2448 *********************************************************************/
2449 static enum cpuhp_state hp_online;
2451 static int cpuhp_cpufreq_online(unsigned int cpu)
2453 cpufreq_online(cpu);
2455 return 0;
2458 static int cpuhp_cpufreq_offline(unsigned int cpu)
2460 cpufreq_offline(cpu);
2462 return 0;
2466 * cpufreq_register_driver - register a CPU Frequency driver
2467 * @driver_data: A struct cpufreq_driver containing the values#
2468 * submitted by the CPU Frequency driver.
2470 * Registers a CPU Frequency driver to this core code. This code
2471 * returns zero on success, -EEXIST when another driver got here first
2472 * (and isn't unregistered in the meantime).
2475 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2477 unsigned long flags;
2478 int ret;
2480 if (cpufreq_disabled())
2481 return -ENODEV;
2484 * The cpufreq core depends heavily on the availability of device
2485 * structure, make sure they are available before proceeding further.
2487 if (!get_cpu_device(0))
2488 return -EPROBE_DEFER;
2490 if (!driver_data || !driver_data->verify || !driver_data->init ||
2491 !(driver_data->setpolicy || driver_data->target_index ||
2492 driver_data->target) ||
2493 (driver_data->setpolicy && (driver_data->target_index ||
2494 driver_data->target)) ||
2495 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2496 return -EINVAL;
2498 pr_debug("trying to register driver %s\n", driver_data->name);
2500 /* Protect against concurrent CPU online/offline. */
2501 cpus_read_lock();
2503 write_lock_irqsave(&cpufreq_driver_lock, flags);
2504 if (cpufreq_driver) {
2505 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2506 ret = -EEXIST;
2507 goto out;
2509 cpufreq_driver = driver_data;
2510 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2512 if (driver_data->setpolicy)
2513 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2515 if (cpufreq_boost_supported()) {
2516 ret = create_boost_sysfs_file();
2517 if (ret)
2518 goto err_null_driver;
2521 ret = subsys_interface_register(&cpufreq_interface);
2522 if (ret)
2523 goto err_boost_unreg;
2525 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2526 list_empty(&cpufreq_policy_list)) {
2527 /* if all ->init() calls failed, unregister */
2528 ret = -ENODEV;
2529 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2530 driver_data->name);
2531 goto err_if_unreg;
2534 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2535 "cpufreq:online",
2536 cpuhp_cpufreq_online,
2537 cpuhp_cpufreq_offline);
2538 if (ret < 0)
2539 goto err_if_unreg;
2540 hp_online = ret;
2541 ret = 0;
2543 pr_debug("driver %s up and running\n", driver_data->name);
2544 goto out;
2546 err_if_unreg:
2547 subsys_interface_unregister(&cpufreq_interface);
2548 err_boost_unreg:
2549 remove_boost_sysfs_file();
2550 err_null_driver:
2551 write_lock_irqsave(&cpufreq_driver_lock, flags);
2552 cpufreq_driver = NULL;
2553 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2554 out:
2555 cpus_read_unlock();
2556 return ret;
2558 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2561 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2563 * Unregister the current CPUFreq driver. Only call this if you have
2564 * the right to do so, i.e. if you have succeeded in initialising before!
2565 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2566 * currently not initialised.
2568 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2570 unsigned long flags;
2572 if (!cpufreq_driver || (driver != cpufreq_driver))
2573 return -EINVAL;
2575 pr_debug("unregistering driver %s\n", driver->name);
2577 /* Protect against concurrent cpu hotplug */
2578 cpus_read_lock();
2579 subsys_interface_unregister(&cpufreq_interface);
2580 remove_boost_sysfs_file();
2581 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2583 write_lock_irqsave(&cpufreq_driver_lock, flags);
2585 cpufreq_driver = NULL;
2587 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2588 cpus_read_unlock();
2590 return 0;
2592 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2594 struct kobject *cpufreq_global_kobject;
2595 EXPORT_SYMBOL(cpufreq_global_kobject);
2597 static int __init cpufreq_core_init(void)
2599 if (cpufreq_disabled())
2600 return -ENODEV;
2602 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2603 BUG_ON(!cpufreq_global_kobject);
2605 return 0;
2607 module_param(off, int, 0444);
2608 core_initcall(cpufreq_core_init);