2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
34 static LIST_HEAD(cpufreq_policy_list);
36 static inline bool policy_is_inactive(struct cpufreq_policy *policy)
38 return cpumask_empty(policy->cpus);
41 /* Macros to iterate over CPU policies */
42 #define for_each_suitable_policy(__policy, __active) \
43 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
44 if ((__active) == !policy_is_inactive(__policy))
46 #define for_each_active_policy(__policy) \
47 for_each_suitable_policy(__policy, true)
48 #define for_each_inactive_policy(__policy) \
49 for_each_suitable_policy(__policy, false)
51 #define for_each_policy(__policy) \
52 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
54 /* Iterate over governors */
55 static LIST_HEAD(cpufreq_governor_list);
56 #define for_each_governor(__governor) \
57 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
60 * The "cpufreq driver" - the arch- or hardware-dependent low
61 * level driver of CPUFreq support, and its spinlock. This lock
62 * also protects the cpufreq_cpu_data array.
64 static struct cpufreq_driver *cpufreq_driver;
65 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
66 static DEFINE_RWLOCK(cpufreq_driver_lock);
68 /* Flag to suspend/resume CPUFreq governors */
69 static bool cpufreq_suspended;
71 static inline bool has_target(void)
73 return cpufreq_driver->target_index || cpufreq_driver->target;
76 /* internal prototypes */
77 static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
78 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
81 * Two notifier lists: the "policy" list is involved in the
82 * validation process for a new CPU frequency policy; the
83 * "transition" list for kernel code that needs to handle
84 * changes to devices when the CPU clock speed changes.
85 * The mutex locks both lists.
87 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
88 static struct srcu_notifier_head cpufreq_transition_notifier_list;
90 static bool init_cpufreq_transition_notifier_list_called;
91 static int __init init_cpufreq_transition_notifier_list(void)
93 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
94 init_cpufreq_transition_notifier_list_called = true;
97 pure_initcall(init_cpufreq_transition_notifier_list);
99 static int off __read_mostly;
100 static int cpufreq_disabled(void)
104 void disable_cpufreq(void)
108 static DEFINE_MUTEX(cpufreq_governor_mutex);
110 bool have_governor_per_policy(void)
112 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
114 EXPORT_SYMBOL_GPL(have_governor_per_policy);
116 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
118 if (have_governor_per_policy())
119 return &policy->kobj;
121 return cpufreq_global_kobject;
123 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
125 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
127 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
129 return policy && !policy_is_inactive(policy) ?
130 policy->freq_table : NULL;
132 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
134 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
140 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
142 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
143 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
144 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
145 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
146 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
147 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
149 idle_time = cur_wall_time - busy_time;
151 *wall = cputime_to_usecs(cur_wall_time);
153 return cputime_to_usecs(idle_time);
156 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
158 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
160 if (idle_time == -1ULL)
161 return get_cpu_idle_time_jiffy(cpu, wall);
163 idle_time += get_cpu_iowait_time_us(cpu, wall);
167 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
170 * This is a generic cpufreq init() routine which can be used by cpufreq
171 * drivers of SMP systems. It will do following:
172 * - validate & show freq table passed
173 * - set policies transition latency
174 * - policy->cpus with all possible CPUs
176 int cpufreq_generic_init(struct cpufreq_policy *policy,
177 struct cpufreq_frequency_table *table,
178 unsigned int transition_latency)
182 ret = cpufreq_table_validate_and_show(policy, table);
184 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
188 policy->cpuinfo.transition_latency = transition_latency;
191 * The driver only supports the SMP configuration where all processors
192 * share the clock and voltage and clock.
194 cpumask_setall(policy->cpus);
198 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
200 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
202 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
204 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
206 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
208 unsigned int cpufreq_generic_get(unsigned int cpu)
210 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
212 if (!policy || IS_ERR(policy->clk)) {
213 pr_err("%s: No %s associated to cpu: %d\n",
214 __func__, policy ? "clk" : "policy", cpu);
218 return clk_get_rate(policy->clk) / 1000;
220 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
223 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
225 * @cpu: cpu to find policy for.
227 * This returns policy for 'cpu', returns NULL if it doesn't exist.
228 * It also increments the kobject reference count to mark it busy and so would
229 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
230 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
231 * freed as that depends on the kobj count.
233 * Return: A valid policy on success, otherwise NULL on failure.
235 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
237 struct cpufreq_policy *policy = NULL;
240 if (WARN_ON(cpu >= nr_cpu_ids))
243 /* get the cpufreq driver */
244 read_lock_irqsave(&cpufreq_driver_lock, flags);
246 if (cpufreq_driver) {
248 policy = cpufreq_cpu_get_raw(cpu);
250 kobject_get(&policy->kobj);
253 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
257 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
260 * cpufreq_cpu_put: Decrements the usage count of a policy
262 * @policy: policy earlier returned by cpufreq_cpu_get().
264 * This decrements the kobject reference count incremented earlier by calling
267 void cpufreq_cpu_put(struct cpufreq_policy *policy)
269 kobject_put(&policy->kobj);
271 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
273 /*********************************************************************
274 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
275 *********************************************************************/
278 * adjust_jiffies - adjust the system "loops_per_jiffy"
280 * This function alters the system "loops_per_jiffy" for the clock
281 * speed change. Note that loops_per_jiffy cannot be updated on SMP
282 * systems as each CPU might be scaled differently. So, use the arch
283 * per-CPU loops_per_jiffy value wherever possible.
285 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
288 static unsigned long l_p_j_ref;
289 static unsigned int l_p_j_ref_freq;
291 if (ci->flags & CPUFREQ_CONST_LOOPS)
294 if (!l_p_j_ref_freq) {
295 l_p_j_ref = loops_per_jiffy;
296 l_p_j_ref_freq = ci->old;
297 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
298 l_p_j_ref, l_p_j_ref_freq);
300 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
301 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
303 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
304 loops_per_jiffy, ci->new);
309 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
310 struct cpufreq_freqs *freqs, unsigned int state)
312 BUG_ON(irqs_disabled());
314 if (cpufreq_disabled())
317 freqs->flags = cpufreq_driver->flags;
318 pr_debug("notification %u of frequency transition to %u kHz\n",
323 case CPUFREQ_PRECHANGE:
324 /* detect if the driver reported a value as "old frequency"
325 * which is not equal to what the cpufreq core thinks is
328 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
329 if ((policy) && (policy->cpu == freqs->cpu) &&
330 (policy->cur) && (policy->cur != freqs->old)) {
331 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
332 freqs->old, policy->cur);
333 freqs->old = policy->cur;
336 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
337 CPUFREQ_PRECHANGE, freqs);
338 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
341 case CPUFREQ_POSTCHANGE:
342 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
343 pr_debug("FREQ: %lu - CPU: %lu\n",
344 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
345 trace_cpu_frequency(freqs->new, freqs->cpu);
346 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
347 CPUFREQ_POSTCHANGE, freqs);
348 if (likely(policy) && likely(policy->cpu == freqs->cpu))
349 policy->cur = freqs->new;
355 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
356 * on frequency transition.
358 * This function calls the transition notifiers and the "adjust_jiffies"
359 * function. It is called twice on all CPU frequency changes that have
362 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
363 struct cpufreq_freqs *freqs, unsigned int state)
365 for_each_cpu(freqs->cpu, policy->cpus)
366 __cpufreq_notify_transition(policy, freqs, state);
369 /* Do post notifications when there are chances that transition has failed */
370 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
371 struct cpufreq_freqs *freqs, int transition_failed)
373 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
374 if (!transition_failed)
377 swap(freqs->old, freqs->new);
378 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
379 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
382 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
383 struct cpufreq_freqs *freqs)
387 * Catch double invocations of _begin() which lead to self-deadlock.
388 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
389 * doesn't invoke _begin() on their behalf, and hence the chances of
390 * double invocations are very low. Moreover, there are scenarios
391 * where these checks can emit false-positive warnings in these
392 * drivers; so we avoid that by skipping them altogether.
394 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
395 && current == policy->transition_task);
398 wait_event(policy->transition_wait, !policy->transition_ongoing);
400 spin_lock(&policy->transition_lock);
402 if (unlikely(policy->transition_ongoing)) {
403 spin_unlock(&policy->transition_lock);
407 policy->transition_ongoing = true;
408 policy->transition_task = current;
410 spin_unlock(&policy->transition_lock);
412 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
414 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
416 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
417 struct cpufreq_freqs *freqs, int transition_failed)
419 if (unlikely(WARN_ON(!policy->transition_ongoing)))
422 cpufreq_notify_post_transition(policy, freqs, transition_failed);
424 policy->transition_ongoing = false;
425 policy->transition_task = NULL;
427 wake_up(&policy->transition_wait);
429 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
432 /*********************************************************************
434 *********************************************************************/
435 static ssize_t show_boost(struct kobject *kobj,
436 struct attribute *attr, char *buf)
438 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
441 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
442 const char *buf, size_t count)
446 ret = sscanf(buf, "%d", &enable);
447 if (ret != 1 || enable < 0 || enable > 1)
450 if (cpufreq_boost_trigger_state(enable)) {
451 pr_err("%s: Cannot %s BOOST!\n",
452 __func__, enable ? "enable" : "disable");
456 pr_debug("%s: cpufreq BOOST %s\n",
457 __func__, enable ? "enabled" : "disabled");
461 define_one_global_rw(boost);
463 static struct cpufreq_governor *find_governor(const char *str_governor)
465 struct cpufreq_governor *t;
468 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
475 * cpufreq_parse_governor - parse a governor string
477 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
478 struct cpufreq_governor **governor)
482 if (cpufreq_driver->setpolicy) {
483 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
484 *policy = CPUFREQ_POLICY_PERFORMANCE;
486 } else if (!strncasecmp(str_governor, "powersave",
488 *policy = CPUFREQ_POLICY_POWERSAVE;
492 struct cpufreq_governor *t;
494 mutex_lock(&cpufreq_governor_mutex);
496 t = find_governor(str_governor);
501 mutex_unlock(&cpufreq_governor_mutex);
502 ret = request_module("cpufreq_%s", str_governor);
503 mutex_lock(&cpufreq_governor_mutex);
506 t = find_governor(str_governor);
514 mutex_unlock(&cpufreq_governor_mutex);
520 * cpufreq_per_cpu_attr_read() / show_##file_name() -
521 * print out cpufreq information
523 * Write out information from cpufreq_driver->policy[cpu]; object must be
527 #define show_one(file_name, object) \
528 static ssize_t show_##file_name \
529 (struct cpufreq_policy *policy, char *buf) \
531 return sprintf(buf, "%u\n", policy->object); \
534 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
535 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
536 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
537 show_one(scaling_min_freq, min);
538 show_one(scaling_max_freq, max);
540 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
544 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
545 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
547 ret = sprintf(buf, "%u\n", policy->cur);
551 static int cpufreq_set_policy(struct cpufreq_policy *policy,
552 struct cpufreq_policy *new_policy);
555 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
557 #define store_one(file_name, object) \
558 static ssize_t store_##file_name \
559 (struct cpufreq_policy *policy, const char *buf, size_t count) \
562 struct cpufreq_policy new_policy; \
564 memcpy(&new_policy, policy, sizeof(*policy)); \
566 ret = sscanf(buf, "%u", &new_policy.object); \
570 temp = new_policy.object; \
571 ret = cpufreq_set_policy(policy, &new_policy); \
573 policy->user_policy.object = temp; \
575 return ret ? ret : count; \
578 store_one(scaling_min_freq, min);
579 store_one(scaling_max_freq, max);
582 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
584 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
587 unsigned int cur_freq = __cpufreq_get(policy);
589 return sprintf(buf, "<unknown>");
590 return sprintf(buf, "%u\n", cur_freq);
594 * show_scaling_governor - show the current policy for the specified CPU
596 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
598 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
599 return sprintf(buf, "powersave\n");
600 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
601 return sprintf(buf, "performance\n");
602 else if (policy->governor)
603 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
604 policy->governor->name);
609 * store_scaling_governor - store policy for the specified CPU
611 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
612 const char *buf, size_t count)
615 char str_governor[16];
616 struct cpufreq_policy new_policy;
618 memcpy(&new_policy, policy, sizeof(*policy));
620 ret = sscanf(buf, "%15s", str_governor);
624 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
625 &new_policy.governor))
628 ret = cpufreq_set_policy(policy, &new_policy);
629 return ret ? ret : count;
633 * show_scaling_driver - show the cpufreq driver currently loaded
635 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
637 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
641 * show_scaling_available_governors - show the available CPUfreq governors
643 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
647 struct cpufreq_governor *t;
650 i += sprintf(buf, "performance powersave");
654 for_each_governor(t) {
655 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
656 - (CPUFREQ_NAME_LEN + 2)))
658 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
661 i += sprintf(&buf[i], "\n");
665 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
670 for_each_cpu(cpu, mask) {
672 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
673 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
674 if (i >= (PAGE_SIZE - 5))
677 i += sprintf(&buf[i], "\n");
680 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
683 * show_related_cpus - show the CPUs affected by each transition even if
684 * hw coordination is in use
686 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
688 return cpufreq_show_cpus(policy->related_cpus, buf);
692 * show_affected_cpus - show the CPUs affected by each transition
694 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
696 return cpufreq_show_cpus(policy->cpus, buf);
699 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
700 const char *buf, size_t count)
702 unsigned int freq = 0;
705 if (!policy->governor || !policy->governor->store_setspeed)
708 ret = sscanf(buf, "%u", &freq);
712 policy->governor->store_setspeed(policy, freq);
717 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
719 if (!policy->governor || !policy->governor->show_setspeed)
720 return sprintf(buf, "<unsupported>\n");
722 return policy->governor->show_setspeed(policy, buf);
726 * show_bios_limit - show the current cpufreq HW/BIOS limitation
728 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
732 if (cpufreq_driver->bios_limit) {
733 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
735 return sprintf(buf, "%u\n", limit);
737 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
740 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
741 cpufreq_freq_attr_ro(cpuinfo_min_freq);
742 cpufreq_freq_attr_ro(cpuinfo_max_freq);
743 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
744 cpufreq_freq_attr_ro(scaling_available_governors);
745 cpufreq_freq_attr_ro(scaling_driver);
746 cpufreq_freq_attr_ro(scaling_cur_freq);
747 cpufreq_freq_attr_ro(bios_limit);
748 cpufreq_freq_attr_ro(related_cpus);
749 cpufreq_freq_attr_ro(affected_cpus);
750 cpufreq_freq_attr_rw(scaling_min_freq);
751 cpufreq_freq_attr_rw(scaling_max_freq);
752 cpufreq_freq_attr_rw(scaling_governor);
753 cpufreq_freq_attr_rw(scaling_setspeed);
755 static struct attribute *default_attrs[] = {
756 &cpuinfo_min_freq.attr,
757 &cpuinfo_max_freq.attr,
758 &cpuinfo_transition_latency.attr,
759 &scaling_min_freq.attr,
760 &scaling_max_freq.attr,
763 &scaling_governor.attr,
764 &scaling_driver.attr,
765 &scaling_available_governors.attr,
766 &scaling_setspeed.attr,
770 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
771 #define to_attr(a) container_of(a, struct freq_attr, attr)
773 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
775 struct cpufreq_policy *policy = to_policy(kobj);
776 struct freq_attr *fattr = to_attr(attr);
779 down_read(&policy->rwsem);
780 ret = fattr->show(policy, buf);
781 up_read(&policy->rwsem);
786 static ssize_t store(struct kobject *kobj, struct attribute *attr,
787 const char *buf, size_t count)
789 struct cpufreq_policy *policy = to_policy(kobj);
790 struct freq_attr *fattr = to_attr(attr);
791 ssize_t ret = -EINVAL;
795 if (cpu_online(policy->cpu)) {
796 down_write(&policy->rwsem);
797 ret = fattr->store(policy, buf, count);
798 up_write(&policy->rwsem);
806 static void cpufreq_sysfs_release(struct kobject *kobj)
808 struct cpufreq_policy *policy = to_policy(kobj);
809 pr_debug("last reference is dropped\n");
810 complete(&policy->kobj_unregister);
813 static const struct sysfs_ops sysfs_ops = {
818 static struct kobj_type ktype_cpufreq = {
819 .sysfs_ops = &sysfs_ops,
820 .default_attrs = default_attrs,
821 .release = cpufreq_sysfs_release,
824 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
826 struct device *cpu_dev;
828 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
833 cpu_dev = get_cpu_device(cpu);
834 if (WARN_ON(!cpu_dev))
837 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
840 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
842 struct device *cpu_dev;
844 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
846 cpu_dev = get_cpu_device(cpu);
847 if (WARN_ON(!cpu_dev))
850 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
853 /* Add/remove symlinks for all related CPUs */
854 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
859 /* Some related CPUs might not be present (physically hotplugged) */
860 for_each_cpu(j, policy->real_cpus) {
861 ret = add_cpu_dev_symlink(policy, j);
869 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
873 /* Some related CPUs might not be present (physically hotplugged) */
874 for_each_cpu(j, policy->real_cpus)
875 remove_cpu_dev_symlink(policy, j);
878 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
880 struct freq_attr **drv_attr;
883 /* set up files for this cpu device */
884 drv_attr = cpufreq_driver->attr;
885 while (drv_attr && *drv_attr) {
886 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
891 if (cpufreq_driver->get) {
892 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
897 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
901 if (cpufreq_driver->bios_limit) {
902 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
907 return cpufreq_add_dev_symlink(policy);
910 __weak struct cpufreq_governor *cpufreq_default_governor(void)
915 static int cpufreq_init_policy(struct cpufreq_policy *policy)
917 struct cpufreq_governor *gov = NULL;
918 struct cpufreq_policy new_policy;
920 memcpy(&new_policy, policy, sizeof(*policy));
922 /* Update governor of new_policy to the governor used before hotplug */
923 gov = find_governor(policy->last_governor);
925 pr_debug("Restoring governor %s for cpu %d\n",
926 policy->governor->name, policy->cpu);
928 gov = cpufreq_default_governor();
933 new_policy.governor = gov;
935 /* Use the default policy if there is no last_policy. */
936 if (cpufreq_driver->setpolicy) {
937 if (policy->last_policy)
938 new_policy.policy = policy->last_policy;
940 cpufreq_parse_governor(gov->name, &new_policy.policy,
943 /* set default policy */
944 return cpufreq_set_policy(policy, &new_policy);
947 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
951 /* Has this CPU been taken care of already? */
952 if (cpumask_test_cpu(cpu, policy->cpus))
955 down_write(&policy->rwsem);
957 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP);
959 pr_err("%s: Failed to stop governor\n", __func__);
964 cpumask_set_cpu(cpu, policy->cpus);
967 ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
969 ret = cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
972 pr_err("%s: Failed to start governor\n", __func__);
976 up_write(&policy->rwsem);
980 static void handle_update(struct work_struct *work)
982 struct cpufreq_policy *policy =
983 container_of(work, struct cpufreq_policy, update);
984 unsigned int cpu = policy->cpu;
985 pr_debug("handle_update for cpu %u called\n", cpu);
986 cpufreq_update_policy(cpu);
989 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
991 struct device *dev = get_cpu_device(cpu);
992 struct cpufreq_policy *policy;
998 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1002 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1003 goto err_free_policy;
1005 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1006 goto err_free_cpumask;
1008 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1009 goto err_free_rcpumask;
1011 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1012 cpufreq_global_kobject, "policy%u", cpu);
1014 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1015 goto err_free_real_cpus;
1018 INIT_LIST_HEAD(&policy->policy_list);
1019 init_rwsem(&policy->rwsem);
1020 spin_lock_init(&policy->transition_lock);
1021 init_waitqueue_head(&policy->transition_wait);
1022 init_completion(&policy->kobj_unregister);
1023 INIT_WORK(&policy->update, handle_update);
1029 free_cpumask_var(policy->real_cpus);
1031 free_cpumask_var(policy->related_cpus);
1033 free_cpumask_var(policy->cpus);
1040 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1042 struct kobject *kobj;
1043 struct completion *cmp;
1046 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1047 CPUFREQ_REMOVE_POLICY, policy);
1049 down_write(&policy->rwsem);
1050 cpufreq_remove_dev_symlink(policy);
1051 kobj = &policy->kobj;
1052 cmp = &policy->kobj_unregister;
1053 up_write(&policy->rwsem);
1057 * We need to make sure that the underlying kobj is
1058 * actually not referenced anymore by anybody before we
1059 * proceed with unloading.
1061 pr_debug("waiting for dropping of refcount\n");
1062 wait_for_completion(cmp);
1063 pr_debug("wait complete\n");
1066 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1068 unsigned long flags;
1071 /* Remove policy from list */
1072 write_lock_irqsave(&cpufreq_driver_lock, flags);
1073 list_del(&policy->policy_list);
1075 for_each_cpu(cpu, policy->related_cpus)
1076 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1077 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1079 cpufreq_policy_put_kobj(policy, notify);
1080 free_cpumask_var(policy->real_cpus);
1081 free_cpumask_var(policy->related_cpus);
1082 free_cpumask_var(policy->cpus);
1086 static int cpufreq_online(unsigned int cpu)
1088 struct cpufreq_policy *policy;
1090 unsigned long flags;
1094 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1096 /* Check if this CPU already has a policy to manage it */
1097 policy = per_cpu(cpufreq_cpu_data, cpu);
1099 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1100 if (!policy_is_inactive(policy))
1101 return cpufreq_add_policy_cpu(policy, cpu);
1103 /* This is the only online CPU for the policy. Start over. */
1105 down_write(&policy->rwsem);
1107 policy->governor = NULL;
1108 up_write(&policy->rwsem);
1111 policy = cpufreq_policy_alloc(cpu);
1116 cpumask_copy(policy->cpus, cpumask_of(cpu));
1118 /* call driver. From then on the cpufreq must be able
1119 * to accept all calls to ->verify and ->setpolicy for this CPU
1121 ret = cpufreq_driver->init(policy);
1123 pr_debug("initialization failed\n");
1124 goto out_free_policy;
1127 down_write(&policy->rwsem);
1130 /* related_cpus should at least include policy->cpus. */
1131 cpumask_copy(policy->related_cpus, policy->cpus);
1132 /* Remember CPUs present at the policy creation time. */
1133 cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
1137 * affected cpus must always be the one, which are online. We aren't
1138 * managing offline cpus here.
1140 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1143 policy->user_policy.min = policy->min;
1144 policy->user_policy.max = policy->max;
1146 write_lock_irqsave(&cpufreq_driver_lock, flags);
1147 for_each_cpu(j, policy->related_cpus)
1148 per_cpu(cpufreq_cpu_data, j) = policy;
1149 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1152 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1153 policy->cur = cpufreq_driver->get(policy->cpu);
1155 pr_err("%s: ->get() failed\n", __func__);
1156 goto out_exit_policy;
1161 * Sometimes boot loaders set CPU frequency to a value outside of
1162 * frequency table present with cpufreq core. In such cases CPU might be
1163 * unstable if it has to run on that frequency for long duration of time
1164 * and so its better to set it to a frequency which is specified in
1165 * freq-table. This also makes cpufreq stats inconsistent as
1166 * cpufreq-stats would fail to register because current frequency of CPU
1167 * isn't found in freq-table.
1169 * Because we don't want this change to effect boot process badly, we go
1170 * for the next freq which is >= policy->cur ('cur' must be set by now,
1171 * otherwise we will end up setting freq to lowest of the table as 'cur'
1172 * is initialized to zero).
1174 * We are passing target-freq as "policy->cur - 1" otherwise
1175 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1176 * equal to target-freq.
1178 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1180 /* Are we running at unknown frequency ? */
1181 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1182 if (ret == -EINVAL) {
1183 /* Warn user and fix it */
1184 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1185 __func__, policy->cpu, policy->cur);
1186 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1187 CPUFREQ_RELATION_L);
1190 * Reaching here after boot in a few seconds may not
1191 * mean that system will remain stable at "unknown"
1192 * frequency for longer duration. Hence, a BUG_ON().
1195 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1196 __func__, policy->cpu, policy->cur);
1200 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1201 CPUFREQ_START, policy);
1204 ret = cpufreq_add_dev_interface(policy);
1206 goto out_exit_policy;
1207 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1208 CPUFREQ_CREATE_POLICY, policy);
1210 write_lock_irqsave(&cpufreq_driver_lock, flags);
1211 list_add(&policy->policy_list, &cpufreq_policy_list);
1212 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1215 ret = cpufreq_init_policy(policy);
1217 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1218 __func__, cpu, ret);
1219 /* cpufreq_policy_free() will notify based on this */
1221 goto out_exit_policy;
1224 up_write(&policy->rwsem);
1226 kobject_uevent(&policy->kobj, KOBJ_ADD);
1228 /* Callback for handling stuff after policy is ready */
1229 if (cpufreq_driver->ready)
1230 cpufreq_driver->ready(policy);
1232 pr_debug("initialization complete\n");
1237 up_write(&policy->rwsem);
1239 if (cpufreq_driver->exit)
1240 cpufreq_driver->exit(policy);
1242 cpufreq_policy_free(policy, !new_policy);
1247 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1249 * @sif: Subsystem interface structure pointer (not used)
1251 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1253 unsigned cpu = dev->id;
1256 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1258 if (cpu_online(cpu)) {
1259 ret = cpufreq_online(cpu);
1262 * A hotplug notifier will follow and we will handle it as CPU
1263 * online then. For now, just create the sysfs link, unless
1264 * there is no policy or the link is already present.
1266 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1268 ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
1269 ? add_cpu_dev_symlink(policy, cpu) : 0;
1275 static void cpufreq_offline(unsigned int cpu)
1277 struct cpufreq_policy *policy;
1280 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1282 policy = cpufreq_cpu_get_raw(cpu);
1284 pr_debug("%s: No cpu_data found\n", __func__);
1288 down_write(&policy->rwsem);
1290 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1292 pr_err("%s: Failed to stop governor\n", __func__);
1295 cpumask_clear_cpu(cpu, policy->cpus);
1297 if (policy_is_inactive(policy)) {
1299 strncpy(policy->last_governor, policy->governor->name,
1302 policy->last_policy = policy->policy;
1303 } else if (cpu == policy->cpu) {
1304 /* Nominate new CPU */
1305 policy->cpu = cpumask_any(policy->cpus);
1308 /* Start governor again for active policy */
1309 if (!policy_is_inactive(policy)) {
1311 ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
1313 ret = cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1316 pr_err("%s: Failed to start governor\n", __func__);
1322 if (cpufreq_driver->stop_cpu)
1323 cpufreq_driver->stop_cpu(policy);
1325 /* If cpu is last user of policy, free policy */
1327 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1329 pr_err("%s: Failed to exit governor\n", __func__);
1333 * Perform the ->exit() even during light-weight tear-down,
1334 * since this is a core component, and is essential for the
1335 * subsequent light-weight ->init() to succeed.
1337 if (cpufreq_driver->exit) {
1338 cpufreq_driver->exit(policy);
1339 policy->freq_table = NULL;
1343 up_write(&policy->rwsem);
1347 * cpufreq_remove_dev - remove a CPU device
1349 * Removes the cpufreq interface for a CPU device.
1351 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1353 unsigned int cpu = dev->id;
1354 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1359 if (cpu_online(cpu))
1360 cpufreq_offline(cpu);
1362 cpumask_clear_cpu(cpu, policy->real_cpus);
1363 remove_cpu_dev_symlink(policy, cpu);
1365 if (cpumask_empty(policy->real_cpus))
1366 cpufreq_policy_free(policy, true);
1370 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1372 * @policy: policy managing CPUs
1373 * @new_freq: CPU frequency the CPU actually runs at
1375 * We adjust to current frequency first, and need to clean up later.
1376 * So either call to cpufreq_update_policy() or schedule handle_update()).
1378 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1379 unsigned int new_freq)
1381 struct cpufreq_freqs freqs;
1383 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1384 policy->cur, new_freq);
1386 freqs.old = policy->cur;
1387 freqs.new = new_freq;
1389 cpufreq_freq_transition_begin(policy, &freqs);
1390 cpufreq_freq_transition_end(policy, &freqs, 0);
1394 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1397 * This is the last known freq, without actually getting it from the driver.
1398 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1400 unsigned int cpufreq_quick_get(unsigned int cpu)
1402 struct cpufreq_policy *policy;
1403 unsigned int ret_freq = 0;
1405 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1406 return cpufreq_driver->get(cpu);
1408 policy = cpufreq_cpu_get(cpu);
1410 ret_freq = policy->cur;
1411 cpufreq_cpu_put(policy);
1416 EXPORT_SYMBOL(cpufreq_quick_get);
1419 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1422 * Just return the max possible frequency for a given CPU.
1424 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1426 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1427 unsigned int ret_freq = 0;
1430 ret_freq = policy->max;
1431 cpufreq_cpu_put(policy);
1436 EXPORT_SYMBOL(cpufreq_quick_get_max);
1438 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1440 unsigned int ret_freq = 0;
1442 if (!cpufreq_driver->get)
1445 ret_freq = cpufreq_driver->get(policy->cpu);
1447 /* Updating inactive policies is invalid, so avoid doing that. */
1448 if (unlikely(policy_is_inactive(policy)))
1451 if (ret_freq && policy->cur &&
1452 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1453 /* verify no discrepancy between actual and
1454 saved value exists */
1455 if (unlikely(ret_freq != policy->cur)) {
1456 cpufreq_out_of_sync(policy, ret_freq);
1457 schedule_work(&policy->update);
1465 * cpufreq_get - get the current CPU frequency (in kHz)
1468 * Get the CPU current (static) CPU frequency
1470 unsigned int cpufreq_get(unsigned int cpu)
1472 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1473 unsigned int ret_freq = 0;
1476 down_read(&policy->rwsem);
1477 ret_freq = __cpufreq_get(policy);
1478 up_read(&policy->rwsem);
1480 cpufreq_cpu_put(policy);
1485 EXPORT_SYMBOL(cpufreq_get);
1487 static struct subsys_interface cpufreq_interface = {
1489 .subsys = &cpu_subsys,
1490 .add_dev = cpufreq_add_dev,
1491 .remove_dev = cpufreq_remove_dev,
1495 * In case platform wants some specific frequency to be configured
1498 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1502 if (!policy->suspend_freq) {
1503 pr_debug("%s: suspend_freq not defined\n", __func__);
1507 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1508 policy->suspend_freq);
1510 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1511 CPUFREQ_RELATION_H);
1513 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1514 __func__, policy->suspend_freq, ret);
1518 EXPORT_SYMBOL(cpufreq_generic_suspend);
1521 * cpufreq_suspend() - Suspend CPUFreq governors
1523 * Called during system wide Suspend/Hibernate cycles for suspending governors
1524 * as some platforms can't change frequency after this point in suspend cycle.
1525 * Because some of the devices (like: i2c, regulators, etc) they use for
1526 * changing frequency are suspended quickly after this point.
1528 void cpufreq_suspend(void)
1530 struct cpufreq_policy *policy;
1533 if (!cpufreq_driver)
1539 pr_debug("%s: Suspending Governors\n", __func__);
1541 for_each_active_policy(policy) {
1542 down_write(&policy->rwsem);
1543 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1544 up_write(&policy->rwsem);
1547 pr_err("%s: Failed to stop governor for policy: %p\n",
1549 else if (cpufreq_driver->suspend
1550 && cpufreq_driver->suspend(policy))
1551 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1556 cpufreq_suspended = true;
1560 * cpufreq_resume() - Resume CPUFreq governors
1562 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1563 * are suspended with cpufreq_suspend().
1565 void cpufreq_resume(void)
1567 struct cpufreq_policy *policy;
1570 if (!cpufreq_driver)
1573 cpufreq_suspended = false;
1578 pr_debug("%s: Resuming Governors\n", __func__);
1580 for_each_active_policy(policy) {
1581 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1582 pr_err("%s: Failed to resume driver: %p\n", __func__,
1585 down_write(&policy->rwsem);
1586 ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
1588 cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1589 up_write(&policy->rwsem);
1592 pr_err("%s: Failed to start governor for policy: %p\n",
1598 * schedule call cpufreq_update_policy() for first-online CPU, as that
1599 * wouldn't be hotplugged-out on suspend. It will verify that the
1600 * current freq is in sync with what we believe it to be.
1602 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1603 if (WARN_ON(!policy))
1606 schedule_work(&policy->update);
1610 * cpufreq_get_current_driver - return current driver's name
1612 * Return the name string of the currently loaded cpufreq driver
1615 const char *cpufreq_get_current_driver(void)
1618 return cpufreq_driver->name;
1622 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1625 * cpufreq_get_driver_data - return current driver data
1627 * Return the private data of the currently loaded cpufreq
1628 * driver, or NULL if no cpufreq driver is loaded.
1630 void *cpufreq_get_driver_data(void)
1633 return cpufreq_driver->driver_data;
1637 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1639 /*********************************************************************
1640 * NOTIFIER LISTS INTERFACE *
1641 *********************************************************************/
1644 * cpufreq_register_notifier - register a driver with cpufreq
1645 * @nb: notifier function to register
1646 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1648 * Add a driver to one of two lists: either a list of drivers that
1649 * are notified about clock rate changes (once before and once after
1650 * the transition), or a list of drivers that are notified about
1651 * changes in cpufreq policy.
1653 * This function may sleep, and has the same return conditions as
1654 * blocking_notifier_chain_register.
1656 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1660 if (cpufreq_disabled())
1663 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1666 case CPUFREQ_TRANSITION_NOTIFIER:
1667 ret = srcu_notifier_chain_register(
1668 &cpufreq_transition_notifier_list, nb);
1670 case CPUFREQ_POLICY_NOTIFIER:
1671 ret = blocking_notifier_chain_register(
1672 &cpufreq_policy_notifier_list, nb);
1680 EXPORT_SYMBOL(cpufreq_register_notifier);
1683 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1684 * @nb: notifier block to be unregistered
1685 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1687 * Remove a driver from the CPU frequency notifier list.
1689 * This function may sleep, and has the same return conditions as
1690 * blocking_notifier_chain_unregister.
1692 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1696 if (cpufreq_disabled())
1700 case CPUFREQ_TRANSITION_NOTIFIER:
1701 ret = srcu_notifier_chain_unregister(
1702 &cpufreq_transition_notifier_list, nb);
1704 case CPUFREQ_POLICY_NOTIFIER:
1705 ret = blocking_notifier_chain_unregister(
1706 &cpufreq_policy_notifier_list, nb);
1714 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1717 /*********************************************************************
1719 *********************************************************************/
1721 /* Must set freqs->new to intermediate frequency */
1722 static int __target_intermediate(struct cpufreq_policy *policy,
1723 struct cpufreq_freqs *freqs, int index)
1727 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1729 /* We don't need to switch to intermediate freq */
1733 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1734 __func__, policy->cpu, freqs->old, freqs->new);
1736 cpufreq_freq_transition_begin(policy, freqs);
1737 ret = cpufreq_driver->target_intermediate(policy, index);
1738 cpufreq_freq_transition_end(policy, freqs, ret);
1741 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1747 static int __target_index(struct cpufreq_policy *policy,
1748 struct cpufreq_frequency_table *freq_table, int index)
1750 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1751 unsigned int intermediate_freq = 0;
1752 int retval = -EINVAL;
1755 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1757 /* Handle switching to intermediate frequency */
1758 if (cpufreq_driver->get_intermediate) {
1759 retval = __target_intermediate(policy, &freqs, index);
1763 intermediate_freq = freqs.new;
1764 /* Set old freq to intermediate */
1765 if (intermediate_freq)
1766 freqs.old = freqs.new;
1769 freqs.new = freq_table[index].frequency;
1770 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1771 __func__, policy->cpu, freqs.old, freqs.new);
1773 cpufreq_freq_transition_begin(policy, &freqs);
1776 retval = cpufreq_driver->target_index(policy, index);
1778 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1782 cpufreq_freq_transition_end(policy, &freqs, retval);
1785 * Failed after setting to intermediate freq? Driver should have
1786 * reverted back to initial frequency and so should we. Check
1787 * here for intermediate_freq instead of get_intermediate, in
1788 * case we haven't switched to intermediate freq at all.
1790 if (unlikely(retval && intermediate_freq)) {
1791 freqs.old = intermediate_freq;
1792 freqs.new = policy->restore_freq;
1793 cpufreq_freq_transition_begin(policy, &freqs);
1794 cpufreq_freq_transition_end(policy, &freqs, 0);
1801 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1802 unsigned int target_freq,
1803 unsigned int relation)
1805 unsigned int old_target_freq = target_freq;
1806 struct cpufreq_frequency_table *freq_table;
1809 if (cpufreq_disabled())
1812 /* Make sure that target_freq is within supported range */
1813 if (target_freq > policy->max)
1814 target_freq = policy->max;
1815 if (target_freq < policy->min)
1816 target_freq = policy->min;
1818 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1819 policy->cpu, target_freq, relation, old_target_freq);
1822 * This might look like a redundant call as we are checking it again
1823 * after finding index. But it is left intentionally for cases where
1824 * exactly same freq is called again and so we can save on few function
1827 if (target_freq == policy->cur)
1830 /* Save last value to restore later on errors */
1831 policy->restore_freq = policy->cur;
1833 if (cpufreq_driver->target)
1834 return cpufreq_driver->target(policy, target_freq, relation);
1836 if (!cpufreq_driver->target_index)
1839 freq_table = cpufreq_frequency_get_table(policy->cpu);
1840 if (unlikely(!freq_table)) {
1841 pr_err("%s: Unable to find freq_table\n", __func__);
1845 retval = cpufreq_frequency_table_target(policy, freq_table, target_freq,
1847 if (unlikely(retval)) {
1848 pr_err("%s: Unable to find matching freq\n", __func__);
1852 if (freq_table[index].frequency == policy->cur)
1855 return __target_index(policy, freq_table, index);
1857 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1859 int cpufreq_driver_target(struct cpufreq_policy *policy,
1860 unsigned int target_freq,
1861 unsigned int relation)
1865 down_write(&policy->rwsem);
1867 ret = __cpufreq_driver_target(policy, target_freq, relation);
1869 up_write(&policy->rwsem);
1873 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1875 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1880 static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1884 /* Don't start any governor operations if we are entering suspend */
1885 if (cpufreq_suspended)
1888 * Governor might not be initiated here if ACPI _PPC changed
1889 * notification happened, so check it.
1891 if (!policy->governor)
1894 if (policy->governor->max_transition_latency &&
1895 policy->cpuinfo.transition_latency >
1896 policy->governor->max_transition_latency) {
1897 struct cpufreq_governor *gov = cpufreq_fallback_governor();
1900 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1901 policy->governor->name, gov->name);
1902 policy->governor = gov;
1908 if (event == CPUFREQ_GOV_POLICY_INIT)
1909 if (!try_module_get(policy->governor->owner))
1912 pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
1914 ret = policy->governor->governor(policy, event);
1917 if (event == CPUFREQ_GOV_POLICY_INIT)
1918 policy->governor->initialized++;
1919 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1920 policy->governor->initialized--;
1923 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
1924 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
1925 module_put(policy->governor->owner);
1930 int cpufreq_register_governor(struct cpufreq_governor *governor)
1937 if (cpufreq_disabled())
1940 mutex_lock(&cpufreq_governor_mutex);
1942 governor->initialized = 0;
1944 if (!find_governor(governor->name)) {
1946 list_add(&governor->governor_list, &cpufreq_governor_list);
1949 mutex_unlock(&cpufreq_governor_mutex);
1952 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1954 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1956 struct cpufreq_policy *policy;
1957 unsigned long flags;
1962 if (cpufreq_disabled())
1965 /* clear last_governor for all inactive policies */
1966 read_lock_irqsave(&cpufreq_driver_lock, flags);
1967 for_each_inactive_policy(policy) {
1968 if (!strcmp(policy->last_governor, governor->name)) {
1969 policy->governor = NULL;
1970 strcpy(policy->last_governor, "\0");
1973 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1975 mutex_lock(&cpufreq_governor_mutex);
1976 list_del(&governor->governor_list);
1977 mutex_unlock(&cpufreq_governor_mutex);
1980 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1983 /*********************************************************************
1984 * POLICY INTERFACE *
1985 *********************************************************************/
1988 * cpufreq_get_policy - get the current cpufreq_policy
1989 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1992 * Reads the current cpufreq policy.
1994 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1996 struct cpufreq_policy *cpu_policy;
2000 cpu_policy = cpufreq_cpu_get(cpu);
2004 memcpy(policy, cpu_policy, sizeof(*policy));
2006 cpufreq_cpu_put(cpu_policy);
2009 EXPORT_SYMBOL(cpufreq_get_policy);
2012 * policy : current policy.
2013 * new_policy: policy to be set.
2015 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2016 struct cpufreq_policy *new_policy)
2018 struct cpufreq_governor *old_gov;
2021 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2022 new_policy->cpu, new_policy->min, new_policy->max);
2024 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2027 * This check works well when we store new min/max freq attributes,
2028 * because new_policy is a copy of policy with one field updated.
2030 if (new_policy->min > new_policy->max)
2033 /* verify the cpu speed can be set within this limit */
2034 ret = cpufreq_driver->verify(new_policy);
2038 /* adjust if necessary - all reasons */
2039 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2040 CPUFREQ_ADJUST, new_policy);
2043 * verify the cpu speed can be set within this limit, which might be
2044 * different to the first one
2046 ret = cpufreq_driver->verify(new_policy);
2050 /* notification of the new policy */
2051 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2052 CPUFREQ_NOTIFY, new_policy);
2054 policy->min = new_policy->min;
2055 policy->max = new_policy->max;
2057 pr_debug("new min and max freqs are %u - %u kHz\n",
2058 policy->min, policy->max);
2060 if (cpufreq_driver->setpolicy) {
2061 policy->policy = new_policy->policy;
2062 pr_debug("setting range\n");
2063 return cpufreq_driver->setpolicy(new_policy);
2066 if (new_policy->governor == policy->governor)
2069 pr_debug("governor switch\n");
2071 /* save old, working values */
2072 old_gov = policy->governor;
2073 /* end old governor */
2075 ret = cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2077 /* This can happen due to race with other operations */
2078 pr_debug("%s: Failed to Stop Governor: %s (%d)\n",
2079 __func__, old_gov->name, ret);
2083 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2085 pr_err("%s: Failed to Exit Governor: %s (%d)\n",
2086 __func__, old_gov->name, ret);
2091 /* start new governor */
2092 policy->governor = new_policy->governor;
2093 ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2095 ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
2099 cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2102 /* new governor failed, so re-start old one */
2103 pr_debug("starting governor %s failed\n", policy->governor->name);
2105 policy->governor = old_gov;
2106 if (cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
2107 policy->governor = NULL;
2109 cpufreq_governor(policy, CPUFREQ_GOV_START);
2115 pr_debug("governor: change or update limits\n");
2116 return cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2120 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2121 * @cpu: CPU which shall be re-evaluated
2123 * Useful for policy notifiers which have different necessities
2124 * at different times.
2126 int cpufreq_update_policy(unsigned int cpu)
2128 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2129 struct cpufreq_policy new_policy;
2135 down_write(&policy->rwsem);
2137 pr_debug("updating policy for CPU %u\n", cpu);
2138 memcpy(&new_policy, policy, sizeof(*policy));
2139 new_policy.min = policy->user_policy.min;
2140 new_policy.max = policy->user_policy.max;
2143 * BIOS might change freq behind our back
2144 * -> ask driver for current freq and notify governors about a change
2146 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2147 new_policy.cur = cpufreq_driver->get(cpu);
2148 if (WARN_ON(!new_policy.cur)) {
2154 pr_debug("Driver did not initialize current freq\n");
2155 policy->cur = new_policy.cur;
2157 if (policy->cur != new_policy.cur && has_target())
2158 cpufreq_out_of_sync(policy, new_policy.cur);
2162 ret = cpufreq_set_policy(policy, &new_policy);
2165 up_write(&policy->rwsem);
2167 cpufreq_cpu_put(policy);
2170 EXPORT_SYMBOL(cpufreq_update_policy);
2172 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2173 unsigned long action, void *hcpu)
2175 unsigned int cpu = (unsigned long)hcpu;
2177 switch (action & ~CPU_TASKS_FROZEN) {
2179 cpufreq_online(cpu);
2182 case CPU_DOWN_PREPARE:
2183 cpufreq_offline(cpu);
2186 case CPU_DOWN_FAILED:
2187 cpufreq_online(cpu);
2193 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2194 .notifier_call = cpufreq_cpu_callback,
2197 /*********************************************************************
2199 *********************************************************************/
2200 static int cpufreq_boost_set_sw(int state)
2202 struct cpufreq_frequency_table *freq_table;
2203 struct cpufreq_policy *policy;
2206 for_each_active_policy(policy) {
2207 freq_table = cpufreq_frequency_get_table(policy->cpu);
2209 ret = cpufreq_frequency_table_cpuinfo(policy,
2212 pr_err("%s: Policy frequency update failed\n",
2217 down_write(&policy->rwsem);
2218 policy->user_policy.max = policy->max;
2219 cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2220 up_write(&policy->rwsem);
2227 int cpufreq_boost_trigger_state(int state)
2229 unsigned long flags;
2232 if (cpufreq_driver->boost_enabled == state)
2235 write_lock_irqsave(&cpufreq_driver_lock, flags);
2236 cpufreq_driver->boost_enabled = state;
2237 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2239 ret = cpufreq_driver->set_boost(state);
2241 write_lock_irqsave(&cpufreq_driver_lock, flags);
2242 cpufreq_driver->boost_enabled = !state;
2243 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2245 pr_err("%s: Cannot %s BOOST\n",
2246 __func__, state ? "enable" : "disable");
2252 static bool cpufreq_boost_supported(void)
2254 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2257 static int create_boost_sysfs_file(void)
2261 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2263 pr_err("%s: cannot register global BOOST sysfs file\n",
2269 static void remove_boost_sysfs_file(void)
2271 if (cpufreq_boost_supported())
2272 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2275 int cpufreq_enable_boost_support(void)
2277 if (!cpufreq_driver)
2280 if (cpufreq_boost_supported())
2283 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2285 /* This will get removed on driver unregister */
2286 return create_boost_sysfs_file();
2288 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2290 int cpufreq_boost_enabled(void)
2292 return cpufreq_driver->boost_enabled;
2294 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2296 /*********************************************************************
2297 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2298 *********************************************************************/
2301 * cpufreq_register_driver - register a CPU Frequency driver
2302 * @driver_data: A struct cpufreq_driver containing the values#
2303 * submitted by the CPU Frequency driver.
2305 * Registers a CPU Frequency driver to this core code. This code
2306 * returns zero on success, -EEXIST when another driver got here first
2307 * (and isn't unregistered in the meantime).
2310 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2312 unsigned long flags;
2315 if (cpufreq_disabled())
2318 if (!driver_data || !driver_data->verify || !driver_data->init ||
2319 !(driver_data->setpolicy || driver_data->target_index ||
2320 driver_data->target) ||
2321 (driver_data->setpolicy && (driver_data->target_index ||
2322 driver_data->target)) ||
2323 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2326 pr_debug("trying to register driver %s\n", driver_data->name);
2328 /* Protect against concurrent CPU online/offline. */
2331 write_lock_irqsave(&cpufreq_driver_lock, flags);
2332 if (cpufreq_driver) {
2333 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2337 cpufreq_driver = driver_data;
2338 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2340 if (driver_data->setpolicy)
2341 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2343 if (cpufreq_boost_supported()) {
2344 ret = create_boost_sysfs_file();
2346 goto err_null_driver;
2349 ret = subsys_interface_register(&cpufreq_interface);
2351 goto err_boost_unreg;
2353 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2354 list_empty(&cpufreq_policy_list)) {
2355 /* if all ->init() calls failed, unregister */
2356 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2361 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2362 pr_debug("driver %s up and running\n", driver_data->name);
2369 subsys_interface_unregister(&cpufreq_interface);
2371 remove_boost_sysfs_file();
2373 write_lock_irqsave(&cpufreq_driver_lock, flags);
2374 cpufreq_driver = NULL;
2375 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2378 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2381 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2383 * Unregister the current CPUFreq driver. Only call this if you have
2384 * the right to do so, i.e. if you have succeeded in initialising before!
2385 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2386 * currently not initialised.
2388 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2390 unsigned long flags;
2392 if (!cpufreq_driver || (driver != cpufreq_driver))
2395 pr_debug("unregistering driver %s\n", driver->name);
2397 /* Protect against concurrent cpu hotplug */
2399 subsys_interface_unregister(&cpufreq_interface);
2400 remove_boost_sysfs_file();
2401 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2403 write_lock_irqsave(&cpufreq_driver_lock, flags);
2405 cpufreq_driver = NULL;
2407 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2412 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2415 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2416 * or mutexes when secondary CPUs are halted.
2418 static struct syscore_ops cpufreq_syscore_ops = {
2419 .shutdown = cpufreq_suspend,
2422 struct kobject *cpufreq_global_kobject;
2423 EXPORT_SYMBOL(cpufreq_global_kobject);
2425 static int __init cpufreq_core_init(void)
2427 if (cpufreq_disabled())
2430 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2431 BUG_ON(!cpufreq_global_kobject);
2433 register_syscore_ops(&cpufreq_syscore_ops);
2437 core_initcall(cpufreq_core_init);