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/syscore_ops.h>
30 #include <linux/tick.h>
31 #include <trace/events/power.h>
34 * The "cpufreq driver" - the arch- or hardware-dependent low
35 * level driver of CPUFreq support, and its spinlock. This lock
36 * also protects the cpufreq_cpu_data array.
38 static struct cpufreq_driver *cpufreq_driver;
39 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
40 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
41 static DEFINE_RWLOCK(cpufreq_driver_lock);
42 DEFINE_MUTEX(cpufreq_governor_lock);
43 static LIST_HEAD(cpufreq_policy_list);
45 #ifdef CONFIG_HOTPLUG_CPU
46 /* This one keeps track of the previously set governor of a removed CPU */
47 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
50 static inline bool has_target(void)
52 return cpufreq_driver->target_index || cpufreq_driver->target;
56 * rwsem to guarantee that cpufreq driver module doesn't unload during critical
59 static DECLARE_RWSEM(cpufreq_rwsem);
61 /* internal prototypes */
62 static int __cpufreq_governor(struct cpufreq_policy *policy,
64 static unsigned int __cpufreq_get(unsigned int cpu);
65 static void handle_update(struct work_struct *work);
68 * Two notifier lists: the "policy" list is involved in the
69 * validation process for a new CPU frequency policy; the
70 * "transition" list for kernel code that needs to handle
71 * changes to devices when the CPU clock speed changes.
72 * The mutex locks both lists.
74 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
75 static struct srcu_notifier_head cpufreq_transition_notifier_list;
77 static bool init_cpufreq_transition_notifier_list_called;
78 static int __init init_cpufreq_transition_notifier_list(void)
80 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
81 init_cpufreq_transition_notifier_list_called = true;
84 pure_initcall(init_cpufreq_transition_notifier_list);
86 static int off __read_mostly;
87 static int cpufreq_disabled(void)
91 void disable_cpufreq(void)
95 static LIST_HEAD(cpufreq_governor_list);
96 static DEFINE_MUTEX(cpufreq_governor_mutex);
98 bool have_governor_per_policy(void)
100 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
102 EXPORT_SYMBOL_GPL(have_governor_per_policy);
104 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
106 if (have_governor_per_policy())
107 return &policy->kobj;
109 return cpufreq_global_kobject;
111 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
113 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
119 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
121 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
122 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
123 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
124 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
125 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
126 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
128 idle_time = cur_wall_time - busy_time;
130 *wall = cputime_to_usecs(cur_wall_time);
132 return cputime_to_usecs(idle_time);
135 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
137 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
139 if (idle_time == -1ULL)
140 return get_cpu_idle_time_jiffy(cpu, wall);
142 idle_time += get_cpu_iowait_time_us(cpu, wall);
146 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
149 * This is a generic cpufreq init() routine which can be used by cpufreq
150 * drivers of SMP systems. It will do following:
151 * - validate & show freq table passed
152 * - set policies transition latency
153 * - policy->cpus with all possible CPUs
155 int cpufreq_generic_init(struct cpufreq_policy *policy,
156 struct cpufreq_frequency_table *table,
157 unsigned int transition_latency)
161 ret = cpufreq_table_validate_and_show(policy, table);
163 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
167 policy->cpuinfo.transition_latency = transition_latency;
170 * The driver only supports the SMP configuartion where all processors
171 * share the clock and voltage and clock.
173 cpumask_setall(policy->cpus);
177 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
179 unsigned int cpufreq_generic_get(unsigned int cpu)
181 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
183 if (!policy || IS_ERR(policy->clk)) {
184 pr_err("%s: No %s associated to cpu: %d\n", __func__,
185 policy ? "clk" : "policy", cpu);
189 return clk_get_rate(policy->clk) / 1000;
191 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
193 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
195 struct cpufreq_policy *policy = NULL;
198 if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
201 if (!down_read_trylock(&cpufreq_rwsem))
204 /* get the cpufreq driver */
205 read_lock_irqsave(&cpufreq_driver_lock, flags);
207 if (cpufreq_driver) {
209 policy = per_cpu(cpufreq_cpu_data, cpu);
211 kobject_get(&policy->kobj);
214 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
217 up_read(&cpufreq_rwsem);
221 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
223 void cpufreq_cpu_put(struct cpufreq_policy *policy)
225 if (cpufreq_disabled())
228 kobject_put(&policy->kobj);
229 up_read(&cpufreq_rwsem);
231 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
233 /*********************************************************************
234 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
235 *********************************************************************/
238 * adjust_jiffies - adjust the system "loops_per_jiffy"
240 * This function alters the system "loops_per_jiffy" for the clock
241 * speed change. Note that loops_per_jiffy cannot be updated on SMP
242 * systems as each CPU might be scaled differently. So, use the arch
243 * per-CPU loops_per_jiffy value wherever possible.
246 static unsigned long l_p_j_ref;
247 static unsigned int l_p_j_ref_freq;
249 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
251 if (ci->flags & CPUFREQ_CONST_LOOPS)
254 if (!l_p_j_ref_freq) {
255 l_p_j_ref = loops_per_jiffy;
256 l_p_j_ref_freq = ci->old;
257 pr_debug("saving %lu as reference value for loops_per_jiffy; "
258 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
260 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
261 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
262 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
264 pr_debug("scaling loops_per_jiffy to %lu "
265 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
269 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
275 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
276 struct cpufreq_freqs *freqs, unsigned int state)
278 BUG_ON(irqs_disabled());
280 if (cpufreq_disabled())
283 freqs->flags = cpufreq_driver->flags;
284 pr_debug("notification %u of frequency transition to %u kHz\n",
289 case CPUFREQ_PRECHANGE:
290 /* detect if the driver reported a value as "old frequency"
291 * which is not equal to what the cpufreq core thinks is
294 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
295 if ((policy) && (policy->cpu == freqs->cpu) &&
296 (policy->cur) && (policy->cur != freqs->old)) {
297 pr_debug("Warning: CPU frequency is"
298 " %u, cpufreq assumed %u kHz.\n",
299 freqs->old, policy->cur);
300 freqs->old = policy->cur;
303 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
304 CPUFREQ_PRECHANGE, freqs);
305 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
308 case CPUFREQ_POSTCHANGE:
309 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
310 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
311 (unsigned long)freqs->cpu);
312 trace_cpu_frequency(freqs->new, freqs->cpu);
313 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
314 CPUFREQ_POSTCHANGE, freqs);
315 if (likely(policy) && likely(policy->cpu == freqs->cpu))
316 policy->cur = freqs->new;
322 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
323 * on frequency transition.
325 * This function calls the transition notifiers and the "adjust_jiffies"
326 * function. It is called twice on all CPU frequency changes that have
329 void cpufreq_notify_transition(struct cpufreq_policy *policy,
330 struct cpufreq_freqs *freqs, unsigned int state)
332 for_each_cpu(freqs->cpu, policy->cpus)
333 __cpufreq_notify_transition(policy, freqs, state);
335 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
337 /* Do post notifications when there are chances that transition has failed */
338 void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
339 struct cpufreq_freqs *freqs, int transition_failed)
341 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
342 if (!transition_failed)
345 swap(freqs->old, freqs->new);
346 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
347 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
349 EXPORT_SYMBOL_GPL(cpufreq_notify_post_transition);
352 /*********************************************************************
354 *********************************************************************/
355 ssize_t show_boost(struct kobject *kobj,
356 struct attribute *attr, char *buf)
358 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
361 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
362 const char *buf, size_t count)
366 ret = sscanf(buf, "%d", &enable);
367 if (ret != 1 || enable < 0 || enable > 1)
370 if (cpufreq_boost_trigger_state(enable)) {
371 pr_err("%s: Cannot %s BOOST!\n", __func__,
372 enable ? "enable" : "disable");
376 pr_debug("%s: cpufreq BOOST %s\n", __func__,
377 enable ? "enabled" : "disabled");
381 define_one_global_rw(boost);
383 static struct cpufreq_governor *__find_governor(const char *str_governor)
385 struct cpufreq_governor *t;
387 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
388 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
395 * cpufreq_parse_governor - parse a governor string
397 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
398 struct cpufreq_governor **governor)
405 if (cpufreq_driver->setpolicy) {
406 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
407 *policy = CPUFREQ_POLICY_PERFORMANCE;
409 } else if (!strnicmp(str_governor, "powersave",
411 *policy = CPUFREQ_POLICY_POWERSAVE;
414 } else if (has_target()) {
415 struct cpufreq_governor *t;
417 mutex_lock(&cpufreq_governor_mutex);
419 t = __find_governor(str_governor);
424 mutex_unlock(&cpufreq_governor_mutex);
425 ret = request_module("cpufreq_%s", str_governor);
426 mutex_lock(&cpufreq_governor_mutex);
429 t = __find_governor(str_governor);
437 mutex_unlock(&cpufreq_governor_mutex);
444 * cpufreq_per_cpu_attr_read() / show_##file_name() -
445 * print out cpufreq information
447 * Write out information from cpufreq_driver->policy[cpu]; object must be
451 #define show_one(file_name, object) \
452 static ssize_t show_##file_name \
453 (struct cpufreq_policy *policy, char *buf) \
455 return sprintf(buf, "%u\n", policy->object); \
458 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
459 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
460 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
461 show_one(scaling_min_freq, min);
462 show_one(scaling_max_freq, max);
463 show_one(scaling_cur_freq, cur);
465 static int cpufreq_set_policy(struct cpufreq_policy *policy,
466 struct cpufreq_policy *new_policy);
469 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
471 #define store_one(file_name, object) \
472 static ssize_t store_##file_name \
473 (struct cpufreq_policy *policy, const char *buf, size_t count) \
476 struct cpufreq_policy new_policy; \
478 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
482 ret = sscanf(buf, "%u", &new_policy.object); \
486 ret = cpufreq_set_policy(policy, &new_policy); \
487 policy->user_policy.object = policy->object; \
489 return ret ? ret : count; \
492 store_one(scaling_min_freq, min);
493 store_one(scaling_max_freq, max);
496 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
498 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
501 unsigned int cur_freq = __cpufreq_get(policy->cpu);
503 return sprintf(buf, "<unknown>");
504 return sprintf(buf, "%u\n", cur_freq);
508 * show_scaling_governor - show the current policy for the specified CPU
510 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
512 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
513 return sprintf(buf, "powersave\n");
514 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
515 return sprintf(buf, "performance\n");
516 else if (policy->governor)
517 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
518 policy->governor->name);
523 * store_scaling_governor - store policy for the specified CPU
525 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
526 const char *buf, size_t count)
529 char str_governor[16];
530 struct cpufreq_policy new_policy;
532 ret = cpufreq_get_policy(&new_policy, policy->cpu);
536 ret = sscanf(buf, "%15s", str_governor);
540 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
541 &new_policy.governor))
544 ret = cpufreq_set_policy(policy, &new_policy);
546 policy->user_policy.policy = policy->policy;
547 policy->user_policy.governor = policy->governor;
556 * show_scaling_driver - show the cpufreq driver currently loaded
558 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
560 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
564 * show_scaling_available_governors - show the available CPUfreq governors
566 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
570 struct cpufreq_governor *t;
573 i += sprintf(buf, "performance powersave");
577 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
578 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
579 - (CPUFREQ_NAME_LEN + 2)))
581 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
584 i += sprintf(&buf[i], "\n");
588 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
593 for_each_cpu(cpu, mask) {
595 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
596 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
597 if (i >= (PAGE_SIZE - 5))
600 i += sprintf(&buf[i], "\n");
603 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
606 * show_related_cpus - show the CPUs affected by each transition even if
607 * hw coordination is in use
609 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
611 return cpufreq_show_cpus(policy->related_cpus, buf);
615 * show_affected_cpus - show the CPUs affected by each transition
617 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
619 return cpufreq_show_cpus(policy->cpus, buf);
622 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
623 const char *buf, size_t count)
625 unsigned int freq = 0;
628 if (!policy->governor || !policy->governor->store_setspeed)
631 ret = sscanf(buf, "%u", &freq);
635 policy->governor->store_setspeed(policy, freq);
640 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
642 if (!policy->governor || !policy->governor->show_setspeed)
643 return sprintf(buf, "<unsupported>\n");
645 return policy->governor->show_setspeed(policy, buf);
649 * show_bios_limit - show the current cpufreq HW/BIOS limitation
651 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
655 if (cpufreq_driver->bios_limit) {
656 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
658 return sprintf(buf, "%u\n", limit);
660 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
663 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
664 cpufreq_freq_attr_ro(cpuinfo_min_freq);
665 cpufreq_freq_attr_ro(cpuinfo_max_freq);
666 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
667 cpufreq_freq_attr_ro(scaling_available_governors);
668 cpufreq_freq_attr_ro(scaling_driver);
669 cpufreq_freq_attr_ro(scaling_cur_freq);
670 cpufreq_freq_attr_ro(bios_limit);
671 cpufreq_freq_attr_ro(related_cpus);
672 cpufreq_freq_attr_ro(affected_cpus);
673 cpufreq_freq_attr_rw(scaling_min_freq);
674 cpufreq_freq_attr_rw(scaling_max_freq);
675 cpufreq_freq_attr_rw(scaling_governor);
676 cpufreq_freq_attr_rw(scaling_setspeed);
678 static struct attribute *default_attrs[] = {
679 &cpuinfo_min_freq.attr,
680 &cpuinfo_max_freq.attr,
681 &cpuinfo_transition_latency.attr,
682 &scaling_min_freq.attr,
683 &scaling_max_freq.attr,
686 &scaling_governor.attr,
687 &scaling_driver.attr,
688 &scaling_available_governors.attr,
689 &scaling_setspeed.attr,
693 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
694 #define to_attr(a) container_of(a, struct freq_attr, attr)
696 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
698 struct cpufreq_policy *policy = to_policy(kobj);
699 struct freq_attr *fattr = to_attr(attr);
702 if (!down_read_trylock(&cpufreq_rwsem))
705 down_read(&policy->rwsem);
708 ret = fattr->show(policy, buf);
712 up_read(&policy->rwsem);
713 up_read(&cpufreq_rwsem);
718 static ssize_t store(struct kobject *kobj, struct attribute *attr,
719 const char *buf, size_t count)
721 struct cpufreq_policy *policy = to_policy(kobj);
722 struct freq_attr *fattr = to_attr(attr);
723 ssize_t ret = -EINVAL;
727 if (!cpu_online(policy->cpu))
730 if (!down_read_trylock(&cpufreq_rwsem))
733 down_write(&policy->rwsem);
736 ret = fattr->store(policy, buf, count);
740 up_write(&policy->rwsem);
742 up_read(&cpufreq_rwsem);
749 static void cpufreq_sysfs_release(struct kobject *kobj)
751 struct cpufreq_policy *policy = to_policy(kobj);
752 pr_debug("last reference is dropped\n");
753 complete(&policy->kobj_unregister);
756 static const struct sysfs_ops sysfs_ops = {
761 static struct kobj_type ktype_cpufreq = {
762 .sysfs_ops = &sysfs_ops,
763 .default_attrs = default_attrs,
764 .release = cpufreq_sysfs_release,
767 struct kobject *cpufreq_global_kobject;
768 EXPORT_SYMBOL(cpufreq_global_kobject);
770 static int cpufreq_global_kobject_usage;
772 int cpufreq_get_global_kobject(void)
774 if (!cpufreq_global_kobject_usage++)
775 return kobject_add(cpufreq_global_kobject,
776 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
780 EXPORT_SYMBOL(cpufreq_get_global_kobject);
782 void cpufreq_put_global_kobject(void)
784 if (!--cpufreq_global_kobject_usage)
785 kobject_del(cpufreq_global_kobject);
787 EXPORT_SYMBOL(cpufreq_put_global_kobject);
789 int cpufreq_sysfs_create_file(const struct attribute *attr)
791 int ret = cpufreq_get_global_kobject();
794 ret = sysfs_create_file(cpufreq_global_kobject, attr);
796 cpufreq_put_global_kobject();
801 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
803 void cpufreq_sysfs_remove_file(const struct attribute *attr)
805 sysfs_remove_file(cpufreq_global_kobject, attr);
806 cpufreq_put_global_kobject();
808 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
810 /* symlink affected CPUs */
811 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
816 for_each_cpu(j, policy->cpus) {
817 struct device *cpu_dev;
819 if (j == policy->cpu)
822 pr_debug("Adding link for CPU: %u\n", j);
823 cpu_dev = get_cpu_device(j);
824 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
832 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
835 struct freq_attr **drv_attr;
838 /* prepare interface data */
839 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
840 &dev->kobj, "cpufreq");
844 /* set up files for this cpu device */
845 drv_attr = cpufreq_driver->attr;
846 while ((drv_attr) && (*drv_attr)) {
847 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
849 goto err_out_kobj_put;
852 if (cpufreq_driver->get) {
853 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
855 goto err_out_kobj_put;
858 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
860 goto err_out_kobj_put;
862 if (cpufreq_driver->bios_limit) {
863 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
865 goto err_out_kobj_put;
868 ret = cpufreq_add_dev_symlink(policy);
870 goto err_out_kobj_put;
875 kobject_put(&policy->kobj);
876 wait_for_completion(&policy->kobj_unregister);
880 static void cpufreq_init_policy(struct cpufreq_policy *policy)
882 struct cpufreq_policy new_policy;
885 memcpy(&new_policy, policy, sizeof(*policy));
887 /* Use the default policy if its valid. */
888 if (cpufreq_driver->setpolicy)
889 cpufreq_parse_governor(policy->governor->name,
890 &new_policy.policy, NULL);
892 /* assure that the starting sequence is run in cpufreq_set_policy */
893 policy->governor = NULL;
895 /* set default policy */
896 ret = cpufreq_set_policy(policy, &new_policy);
898 pr_debug("setting policy failed\n");
899 if (cpufreq_driver->exit)
900 cpufreq_driver->exit(policy);
904 #ifdef CONFIG_HOTPLUG_CPU
905 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
906 unsigned int cpu, struct device *dev)
912 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
914 pr_err("%s: Failed to stop governor\n", __func__);
919 down_write(&policy->rwsem);
921 write_lock_irqsave(&cpufreq_driver_lock, flags);
923 cpumask_set_cpu(cpu, policy->cpus);
924 per_cpu(cpufreq_cpu_data, cpu) = policy;
925 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
927 up_write(&policy->rwsem);
930 if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||
931 (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) {
932 pr_err("%s: Failed to start governor\n", __func__);
937 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
941 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
943 struct cpufreq_policy *policy;
946 read_lock_irqsave(&cpufreq_driver_lock, flags);
948 policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
950 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
955 static struct cpufreq_policy *cpufreq_policy_alloc(void)
957 struct cpufreq_policy *policy;
959 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
963 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
964 goto err_free_policy;
966 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
967 goto err_free_cpumask;
969 INIT_LIST_HEAD(&policy->policy_list);
970 init_rwsem(&policy->rwsem);
975 free_cpumask_var(policy->cpus);
982 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
984 struct kobject *kobj;
985 struct completion *cmp;
987 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
988 CPUFREQ_REMOVE_POLICY, policy);
990 down_read(&policy->rwsem);
991 kobj = &policy->kobj;
992 cmp = &policy->kobj_unregister;
993 up_read(&policy->rwsem);
997 * We need to make sure that the underlying kobj is
998 * actually not referenced anymore by anybody before we
999 * proceed with unloading.
1001 pr_debug("waiting for dropping of refcount\n");
1002 wait_for_completion(cmp);
1003 pr_debug("wait complete\n");
1006 static void cpufreq_policy_free(struct cpufreq_policy *policy)
1008 free_cpumask_var(policy->related_cpus);
1009 free_cpumask_var(policy->cpus);
1013 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1015 if (WARN_ON(cpu == policy->cpu))
1018 down_write(&policy->rwsem);
1020 policy->last_cpu = policy->cpu;
1023 up_write(&policy->rwsem);
1025 cpufreq_frequency_table_update_policy_cpu(policy);
1026 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1027 CPUFREQ_UPDATE_POLICY_CPU, policy);
1030 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
1033 unsigned int j, cpu = dev->id;
1035 struct cpufreq_policy *policy;
1036 unsigned long flags;
1037 #ifdef CONFIG_HOTPLUG_CPU
1038 struct cpufreq_policy *tpolicy;
1039 struct cpufreq_governor *gov;
1042 if (cpu_is_offline(cpu))
1045 pr_debug("adding CPU %u\n", cpu);
1048 /* check whether a different CPU already registered this
1049 * CPU because it is in the same boat. */
1050 policy = cpufreq_cpu_get(cpu);
1051 if (unlikely(policy)) {
1052 cpufreq_cpu_put(policy);
1057 if (!down_read_trylock(&cpufreq_rwsem))
1060 #ifdef CONFIG_HOTPLUG_CPU
1061 /* Check if this cpu was hot-unplugged earlier and has siblings */
1062 read_lock_irqsave(&cpufreq_driver_lock, flags);
1063 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1064 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1065 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1066 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1067 up_read(&cpufreq_rwsem);
1071 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1075 * Restore the saved policy when doing light-weight init and fall back
1076 * to the full init if that fails.
1078 policy = frozen ? cpufreq_policy_restore(cpu) : NULL;
1081 policy = cpufreq_policy_alloc();
1087 * In the resume path, since we restore a saved policy, the assignment
1088 * to policy->cpu is like an update of the existing policy, rather than
1089 * the creation of a brand new one. So we need to perform this update
1090 * by invoking update_policy_cpu().
1092 if (frozen && cpu != policy->cpu) {
1093 update_policy_cpu(policy, cpu);
1094 WARN_ON(kobject_move(&policy->kobj, &dev->kobj));
1099 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
1100 cpumask_copy(policy->cpus, cpumask_of(cpu));
1102 init_completion(&policy->kobj_unregister);
1103 INIT_WORK(&policy->update, handle_update);
1105 /* call driver. From then on the cpufreq must be able
1106 * to accept all calls to ->verify and ->setpolicy for this CPU
1108 ret = cpufreq_driver->init(policy);
1110 pr_debug("initialization failed\n");
1111 goto err_set_policy_cpu;
1114 /* related cpus should atleast have policy->cpus */
1115 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1118 * affected cpus must always be the one, which are online. We aren't
1119 * managing offline cpus here.
1121 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1124 policy->user_policy.min = policy->min;
1125 policy->user_policy.max = policy->max;
1128 down_write(&policy->rwsem);
1129 write_lock_irqsave(&cpufreq_driver_lock, flags);
1130 for_each_cpu(j, policy->cpus)
1131 per_cpu(cpufreq_cpu_data, j) = policy;
1132 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1134 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1135 policy->cur = cpufreq_driver->get(policy->cpu);
1137 pr_err("%s: ->get() failed\n", __func__);
1143 * Sometimes boot loaders set CPU frequency to a value outside of
1144 * frequency table present with cpufreq core. In such cases CPU might be
1145 * unstable if it has to run on that frequency for long duration of time
1146 * and so its better to set it to a frequency which is specified in
1147 * freq-table. This also makes cpufreq stats inconsistent as
1148 * cpufreq-stats would fail to register because current frequency of CPU
1149 * isn't found in freq-table.
1151 * Because we don't want this change to effect boot process badly, we go
1152 * for the next freq which is >= policy->cur ('cur' must be set by now,
1153 * otherwise we will end up setting freq to lowest of the table as 'cur'
1154 * is initialized to zero).
1156 * We are passing target-freq as "policy->cur - 1" otherwise
1157 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1158 * equal to target-freq.
1160 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1162 /* Are we running at unknown frequency ? */
1163 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1164 if (ret == -EINVAL) {
1165 /* Warn user and fix it */
1166 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1167 __func__, policy->cpu, policy->cur);
1168 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1169 CPUFREQ_RELATION_L);
1172 * Reaching here after boot in a few seconds may not
1173 * mean that system will remain stable at "unknown"
1174 * frequency for longer duration. Hence, a BUG_ON().
1177 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1178 __func__, policy->cpu, policy->cur);
1182 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1183 CPUFREQ_START, policy);
1185 #ifdef CONFIG_HOTPLUG_CPU
1186 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
1188 policy->governor = gov;
1189 pr_debug("Restoring governor %s for cpu %d\n",
1190 policy->governor->name, cpu);
1195 ret = cpufreq_add_dev_interface(policy, dev);
1197 goto err_out_unregister;
1198 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1199 CPUFREQ_CREATE_POLICY, policy);
1202 write_lock_irqsave(&cpufreq_driver_lock, flags);
1203 list_add(&policy->policy_list, &cpufreq_policy_list);
1204 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1206 cpufreq_init_policy(policy);
1209 policy->user_policy.policy = policy->policy;
1210 policy->user_policy.governor = policy->governor;
1212 up_write(&policy->rwsem);
1214 kobject_uevent(&policy->kobj, KOBJ_ADD);
1215 up_read(&cpufreq_rwsem);
1217 pr_debug("initialization complete\n");
1223 write_lock_irqsave(&cpufreq_driver_lock, flags);
1224 for_each_cpu(j, policy->cpus)
1225 per_cpu(cpufreq_cpu_data, j) = NULL;
1226 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1228 if (cpufreq_driver->exit)
1229 cpufreq_driver->exit(policy);
1232 /* Do not leave stale fallback data behind. */
1233 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1234 cpufreq_policy_put_kobj(policy);
1236 cpufreq_policy_free(policy);
1239 up_read(&cpufreq_rwsem);
1245 * cpufreq_add_dev - add a CPU device
1247 * Adds the cpufreq interface for a CPU device.
1249 * The Oracle says: try running cpufreq registration/unregistration concurrently
1250 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1251 * mess up, but more thorough testing is needed. - Mathieu
1253 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1255 return __cpufreq_add_dev(dev, sif, false);
1258 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
1259 unsigned int old_cpu)
1261 struct device *cpu_dev;
1264 /* first sibling now owns the new sysfs dir */
1265 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
1267 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1268 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1270 pr_err("%s: Failed to move kobj: %d", __func__, ret);
1272 down_write(&policy->rwsem);
1273 cpumask_set_cpu(old_cpu, policy->cpus);
1274 up_write(&policy->rwsem);
1276 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1285 static int __cpufreq_remove_dev_prepare(struct device *dev,
1286 struct subsys_interface *sif,
1289 unsigned int cpu = dev->id, cpus;
1291 unsigned long flags;
1292 struct cpufreq_policy *policy;
1294 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1296 write_lock_irqsave(&cpufreq_driver_lock, flags);
1298 policy = per_cpu(cpufreq_cpu_data, cpu);
1300 /* Save the policy somewhere when doing a light-weight tear-down */
1302 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1304 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1307 pr_debug("%s: No cpu_data found\n", __func__);
1312 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1314 pr_err("%s: Failed to stop governor\n", __func__);
1319 #ifdef CONFIG_HOTPLUG_CPU
1320 if (!cpufreq_driver->setpolicy)
1321 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1322 policy->governor->name, CPUFREQ_NAME_LEN);
1325 down_read(&policy->rwsem);
1326 cpus = cpumask_weight(policy->cpus);
1327 up_read(&policy->rwsem);
1329 if (cpu != policy->cpu) {
1330 sysfs_remove_link(&dev->kobj, "cpufreq");
1331 } else if (cpus > 1) {
1332 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
1334 update_policy_cpu(policy, new_cpu);
1337 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1338 __func__, new_cpu, cpu);
1346 static int __cpufreq_remove_dev_finish(struct device *dev,
1347 struct subsys_interface *sif,
1350 unsigned int cpu = dev->id, cpus;
1352 unsigned long flags;
1353 struct cpufreq_policy *policy;
1355 read_lock_irqsave(&cpufreq_driver_lock, flags);
1356 policy = per_cpu(cpufreq_cpu_data, cpu);
1357 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1360 pr_debug("%s: No cpu_data found\n", __func__);
1364 down_write(&policy->rwsem);
1365 cpus = cpumask_weight(policy->cpus);
1368 cpumask_clear_cpu(cpu, policy->cpus);
1369 up_write(&policy->rwsem);
1371 /* If cpu is last user of policy, free policy */
1374 ret = __cpufreq_governor(policy,
1375 CPUFREQ_GOV_POLICY_EXIT);
1377 pr_err("%s: Failed to exit governor\n",
1384 cpufreq_policy_put_kobj(policy);
1387 * Perform the ->exit() even during light-weight tear-down,
1388 * since this is a core component, and is essential for the
1389 * subsequent light-weight ->init() to succeed.
1391 if (cpufreq_driver->exit)
1392 cpufreq_driver->exit(policy);
1394 /* Remove policy from list of active policies */
1395 write_lock_irqsave(&cpufreq_driver_lock, flags);
1396 list_del(&policy->policy_list);
1397 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1400 cpufreq_policy_free(policy);
1403 if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||
1404 (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) {
1405 pr_err("%s: Failed to start governor\n",
1412 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1417 * cpufreq_remove_dev - remove a CPU device
1419 * Removes the cpufreq interface for a CPU device.
1421 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1423 unsigned int cpu = dev->id;
1426 if (cpu_is_offline(cpu))
1429 ret = __cpufreq_remove_dev_prepare(dev, sif, false);
1432 ret = __cpufreq_remove_dev_finish(dev, sif, false);
1437 static void handle_update(struct work_struct *work)
1439 struct cpufreq_policy *policy =
1440 container_of(work, struct cpufreq_policy, update);
1441 unsigned int cpu = policy->cpu;
1442 pr_debug("handle_update for cpu %u called\n", cpu);
1443 cpufreq_update_policy(cpu);
1447 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1450 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1451 * @new_freq: CPU frequency the CPU actually runs at
1453 * We adjust to current frequency first, and need to clean up later.
1454 * So either call to cpufreq_update_policy() or schedule handle_update()).
1456 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1457 unsigned int new_freq)
1459 struct cpufreq_policy *policy;
1460 struct cpufreq_freqs freqs;
1461 unsigned long flags;
1463 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1464 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1466 freqs.old = old_freq;
1467 freqs.new = new_freq;
1469 read_lock_irqsave(&cpufreq_driver_lock, flags);
1470 policy = per_cpu(cpufreq_cpu_data, cpu);
1471 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1473 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
1474 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
1478 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1481 * This is the last known freq, without actually getting it from the driver.
1482 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1484 unsigned int cpufreq_quick_get(unsigned int cpu)
1486 struct cpufreq_policy *policy;
1487 unsigned int ret_freq = 0;
1489 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1490 return cpufreq_driver->get(cpu);
1492 policy = cpufreq_cpu_get(cpu);
1494 ret_freq = policy->cur;
1495 cpufreq_cpu_put(policy);
1500 EXPORT_SYMBOL(cpufreq_quick_get);
1503 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1506 * Just return the max possible frequency for a given CPU.
1508 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1510 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1511 unsigned int ret_freq = 0;
1514 ret_freq = policy->max;
1515 cpufreq_cpu_put(policy);
1520 EXPORT_SYMBOL(cpufreq_quick_get_max);
1522 static unsigned int __cpufreq_get(unsigned int cpu)
1524 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1525 unsigned int ret_freq = 0;
1527 if (!cpufreq_driver->get)
1530 ret_freq = cpufreq_driver->get(cpu);
1532 if (ret_freq && policy->cur &&
1533 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1534 /* verify no discrepancy between actual and
1535 saved value exists */
1536 if (unlikely(ret_freq != policy->cur)) {
1537 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1538 schedule_work(&policy->update);
1546 * cpufreq_get - get the current CPU frequency (in kHz)
1549 * Get the CPU current (static) CPU frequency
1551 unsigned int cpufreq_get(unsigned int cpu)
1553 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1554 unsigned int ret_freq = 0;
1557 down_read(&policy->rwsem);
1558 ret_freq = __cpufreq_get(cpu);
1559 up_read(&policy->rwsem);
1561 cpufreq_cpu_put(policy);
1566 EXPORT_SYMBOL(cpufreq_get);
1568 static struct subsys_interface cpufreq_interface = {
1570 .subsys = &cpu_subsys,
1571 .add_dev = cpufreq_add_dev,
1572 .remove_dev = cpufreq_remove_dev,
1576 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1578 * This function is only executed for the boot processor. The other CPUs
1579 * have been put offline by means of CPU hotplug.
1581 static int cpufreq_bp_suspend(void)
1585 int cpu = smp_processor_id();
1586 struct cpufreq_policy *policy;
1588 pr_debug("suspending cpu %u\n", cpu);
1590 /* If there's no policy for the boot CPU, we have nothing to do. */
1591 policy = cpufreq_cpu_get(cpu);
1595 if (cpufreq_driver->suspend) {
1596 ret = cpufreq_driver->suspend(policy);
1598 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1599 "step on CPU %u\n", policy->cpu);
1602 cpufreq_cpu_put(policy);
1607 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1609 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1610 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1611 * restored. It will verify that the current freq is in sync with
1612 * what we believe it to be. This is a bit later than when it
1613 * should be, but nonethteless it's better than calling
1614 * cpufreq_driver->get() here which might re-enable interrupts...
1616 * This function is only executed for the boot CPU. The other CPUs have not
1617 * been turned on yet.
1619 static void cpufreq_bp_resume(void)
1623 int cpu = smp_processor_id();
1624 struct cpufreq_policy *policy;
1626 pr_debug("resuming cpu %u\n", cpu);
1628 /* If there's no policy for the boot CPU, we have nothing to do. */
1629 policy = cpufreq_cpu_get(cpu);
1633 if (cpufreq_driver->resume) {
1634 ret = cpufreq_driver->resume(policy);
1636 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1637 "step on CPU %u\n", policy->cpu);
1642 schedule_work(&policy->update);
1645 cpufreq_cpu_put(policy);
1648 static struct syscore_ops cpufreq_syscore_ops = {
1649 .suspend = cpufreq_bp_suspend,
1650 .resume = cpufreq_bp_resume,
1654 * cpufreq_get_current_driver - return current driver's name
1656 * Return the name string of the currently loaded cpufreq driver
1659 const char *cpufreq_get_current_driver(void)
1662 return cpufreq_driver->name;
1666 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1668 /*********************************************************************
1669 * NOTIFIER LISTS INTERFACE *
1670 *********************************************************************/
1673 * cpufreq_register_notifier - register a driver with cpufreq
1674 * @nb: notifier function to register
1675 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1677 * Add a driver to one of two lists: either a list of drivers that
1678 * are notified about clock rate changes (once before and once after
1679 * the transition), or a list of drivers that are notified about
1680 * changes in cpufreq policy.
1682 * This function may sleep, and has the same return conditions as
1683 * blocking_notifier_chain_register.
1685 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1689 if (cpufreq_disabled())
1692 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1695 case CPUFREQ_TRANSITION_NOTIFIER:
1696 ret = srcu_notifier_chain_register(
1697 &cpufreq_transition_notifier_list, nb);
1699 case CPUFREQ_POLICY_NOTIFIER:
1700 ret = blocking_notifier_chain_register(
1701 &cpufreq_policy_notifier_list, nb);
1709 EXPORT_SYMBOL(cpufreq_register_notifier);
1712 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1713 * @nb: notifier block to be unregistered
1714 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1716 * Remove a driver from the CPU frequency notifier list.
1718 * This function may sleep, and has the same return conditions as
1719 * blocking_notifier_chain_unregister.
1721 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1725 if (cpufreq_disabled())
1729 case CPUFREQ_TRANSITION_NOTIFIER:
1730 ret = srcu_notifier_chain_unregister(
1731 &cpufreq_transition_notifier_list, nb);
1733 case CPUFREQ_POLICY_NOTIFIER:
1734 ret = blocking_notifier_chain_unregister(
1735 &cpufreq_policy_notifier_list, nb);
1743 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1746 /*********************************************************************
1748 *********************************************************************/
1750 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1751 unsigned int target_freq,
1752 unsigned int relation)
1754 int retval = -EINVAL;
1755 unsigned int old_target_freq = target_freq;
1757 if (cpufreq_disabled())
1760 /* Make sure that target_freq is within supported range */
1761 if (target_freq > policy->max)
1762 target_freq = policy->max;
1763 if (target_freq < policy->min)
1764 target_freq = policy->min;
1766 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1767 policy->cpu, target_freq, relation, old_target_freq);
1770 * This might look like a redundant call as we are checking it again
1771 * after finding index. But it is left intentionally for cases where
1772 * exactly same freq is called again and so we can save on few function
1775 if (target_freq == policy->cur)
1778 if (cpufreq_driver->target)
1779 retval = cpufreq_driver->target(policy, target_freq, relation);
1780 else if (cpufreq_driver->target_index) {
1781 struct cpufreq_frequency_table *freq_table;
1782 struct cpufreq_freqs freqs;
1786 freq_table = cpufreq_frequency_get_table(policy->cpu);
1787 if (unlikely(!freq_table)) {
1788 pr_err("%s: Unable to find freq_table\n", __func__);
1792 retval = cpufreq_frequency_table_target(policy, freq_table,
1793 target_freq, relation, &index);
1794 if (unlikely(retval)) {
1795 pr_err("%s: Unable to find matching freq\n", __func__);
1799 if (freq_table[index].frequency == policy->cur) {
1804 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1807 freqs.old = policy->cur;
1808 freqs.new = freq_table[index].frequency;
1811 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1812 __func__, policy->cpu, freqs.old,
1815 cpufreq_notify_transition(policy, &freqs,
1819 retval = cpufreq_driver->target_index(policy, index);
1821 pr_err("%s: Failed to change cpu frequency: %d\n",
1825 cpufreq_notify_post_transition(policy, &freqs, retval);
1831 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1833 int cpufreq_driver_target(struct cpufreq_policy *policy,
1834 unsigned int target_freq,
1835 unsigned int relation)
1839 down_write(&policy->rwsem);
1841 ret = __cpufreq_driver_target(policy, target_freq, relation);
1843 up_write(&policy->rwsem);
1847 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1850 * when "event" is CPUFREQ_GOV_LIMITS
1853 static int __cpufreq_governor(struct cpufreq_policy *policy,
1858 /* Only must be defined when default governor is known to have latency
1859 restrictions, like e.g. conservative or ondemand.
1860 That this is the case is already ensured in Kconfig
1862 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1863 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1865 struct cpufreq_governor *gov = NULL;
1868 if (policy->governor->max_transition_latency &&
1869 policy->cpuinfo.transition_latency >
1870 policy->governor->max_transition_latency) {
1874 printk(KERN_WARNING "%s governor failed, too long"
1875 " transition latency of HW, fallback"
1876 " to %s governor\n",
1877 policy->governor->name,
1879 policy->governor = gov;
1883 if (event == CPUFREQ_GOV_POLICY_INIT)
1884 if (!try_module_get(policy->governor->owner))
1887 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1888 policy->cpu, event);
1890 mutex_lock(&cpufreq_governor_lock);
1891 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1892 || (!policy->governor_enabled
1893 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1894 mutex_unlock(&cpufreq_governor_lock);
1898 if (event == CPUFREQ_GOV_STOP)
1899 policy->governor_enabled = false;
1900 else if (event == CPUFREQ_GOV_START)
1901 policy->governor_enabled = true;
1903 mutex_unlock(&cpufreq_governor_lock);
1905 ret = policy->governor->governor(policy, event);
1908 if (event == CPUFREQ_GOV_POLICY_INIT)
1909 policy->governor->initialized++;
1910 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1911 policy->governor->initialized--;
1913 /* Restore original values */
1914 mutex_lock(&cpufreq_governor_lock);
1915 if (event == CPUFREQ_GOV_STOP)
1916 policy->governor_enabled = true;
1917 else if (event == CPUFREQ_GOV_START)
1918 policy->governor_enabled = false;
1919 mutex_unlock(&cpufreq_governor_lock);
1922 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
1923 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
1924 module_put(policy->governor->owner);
1929 int cpufreq_register_governor(struct cpufreq_governor *governor)
1936 if (cpufreq_disabled())
1939 mutex_lock(&cpufreq_governor_mutex);
1941 governor->initialized = 0;
1943 if (__find_governor(governor->name) == NULL) {
1945 list_add(&governor->governor_list, &cpufreq_governor_list);
1948 mutex_unlock(&cpufreq_governor_mutex);
1951 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1953 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1955 #ifdef CONFIG_HOTPLUG_CPU
1962 if (cpufreq_disabled())
1965 #ifdef CONFIG_HOTPLUG_CPU
1966 for_each_present_cpu(cpu) {
1967 if (cpu_online(cpu))
1969 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1970 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1974 mutex_lock(&cpufreq_governor_mutex);
1975 list_del(&governor->governor_list);
1976 mutex_unlock(&cpufreq_governor_mutex);
1979 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1982 /*********************************************************************
1983 * POLICY INTERFACE *
1984 *********************************************************************/
1987 * cpufreq_get_policy - get the current cpufreq_policy
1988 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1991 * Reads the current cpufreq policy.
1993 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1995 struct cpufreq_policy *cpu_policy;
1999 cpu_policy = cpufreq_cpu_get(cpu);
2003 memcpy(policy, cpu_policy, sizeof(*policy));
2005 cpufreq_cpu_put(cpu_policy);
2008 EXPORT_SYMBOL(cpufreq_get_policy);
2011 * policy : current policy.
2012 * new_policy: policy to be set.
2014 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2015 struct cpufreq_policy *new_policy)
2017 int ret = 0, failed = 1;
2019 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu,
2020 new_policy->min, new_policy->max);
2022 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2024 if (new_policy->min > policy->max || new_policy->max < policy->min) {
2029 /* verify the cpu speed can be set within this limit */
2030 ret = cpufreq_driver->verify(new_policy);
2034 /* adjust if necessary - all reasons */
2035 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2036 CPUFREQ_ADJUST, new_policy);
2038 /* adjust if necessary - hardware incompatibility*/
2039 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2040 CPUFREQ_INCOMPATIBLE, 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 ret = cpufreq_driver->setpolicy(new_policy);
2065 if (new_policy->governor != policy->governor) {
2066 /* save old, working values */
2067 struct cpufreq_governor *old_gov = policy->governor;
2069 pr_debug("governor switch\n");
2071 /* end old governor */
2072 if (policy->governor) {
2073 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2074 up_write(&policy->rwsem);
2075 __cpufreq_governor(policy,
2076 CPUFREQ_GOV_POLICY_EXIT);
2077 down_write(&policy->rwsem);
2080 /* start new governor */
2081 policy->governor = new_policy->governor;
2082 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2083 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
2086 up_write(&policy->rwsem);
2087 __cpufreq_governor(policy,
2088 CPUFREQ_GOV_POLICY_EXIT);
2089 down_write(&policy->rwsem);
2094 /* new governor failed, so re-start old one */
2095 pr_debug("starting governor %s failed\n",
2096 policy->governor->name);
2098 policy->governor = old_gov;
2099 __cpufreq_governor(policy,
2100 CPUFREQ_GOV_POLICY_INIT);
2101 __cpufreq_governor(policy,
2107 /* might be a policy change, too, so fall through */
2109 pr_debug("governor: change or update limits\n");
2110 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2118 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2119 * @cpu: CPU which shall be re-evaluated
2121 * Useful for policy notifiers which have different necessities
2122 * at different times.
2124 int cpufreq_update_policy(unsigned int cpu)
2126 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2127 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;
2141 new_policy.policy = policy->user_policy.policy;
2142 new_policy.governor = policy->user_policy.governor;
2145 * BIOS might change freq behind our back
2146 * -> ask driver for current freq and notify governors about a change
2148 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2149 new_policy.cur = cpufreq_driver->get(cpu);
2151 pr_debug("Driver did not initialize current freq");
2152 policy->cur = new_policy.cur;
2154 if (policy->cur != new_policy.cur && has_target())
2155 cpufreq_out_of_sync(cpu, policy->cur,
2160 ret = cpufreq_set_policy(policy, &new_policy);
2162 up_write(&policy->rwsem);
2164 cpufreq_cpu_put(policy);
2168 EXPORT_SYMBOL(cpufreq_update_policy);
2170 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2171 unsigned long action, void *hcpu)
2173 unsigned int cpu = (unsigned long)hcpu;
2175 bool frozen = false;
2177 dev = get_cpu_device(cpu);
2180 if (action & CPU_TASKS_FROZEN)
2183 switch (action & ~CPU_TASKS_FROZEN) {
2185 __cpufreq_add_dev(dev, NULL, frozen);
2186 cpufreq_update_policy(cpu);
2189 case CPU_DOWN_PREPARE:
2190 __cpufreq_remove_dev_prepare(dev, NULL, frozen);
2194 __cpufreq_remove_dev_finish(dev, NULL, frozen);
2197 case CPU_DOWN_FAILED:
2198 __cpufreq_add_dev(dev, NULL, frozen);
2205 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2206 .notifier_call = cpufreq_cpu_callback,
2209 /*********************************************************************
2211 *********************************************************************/
2212 static int cpufreq_boost_set_sw(int state)
2214 struct cpufreq_frequency_table *freq_table;
2215 struct cpufreq_policy *policy;
2218 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2219 freq_table = cpufreq_frequency_get_table(policy->cpu);
2221 ret = cpufreq_frequency_table_cpuinfo(policy,
2224 pr_err("%s: Policy frequency update failed\n",
2228 policy->user_policy.max = policy->max;
2229 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2236 int cpufreq_boost_trigger_state(int state)
2238 unsigned long flags;
2241 if (cpufreq_driver->boost_enabled == state)
2244 write_lock_irqsave(&cpufreq_driver_lock, flags);
2245 cpufreq_driver->boost_enabled = state;
2246 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2248 ret = cpufreq_driver->set_boost(state);
2250 write_lock_irqsave(&cpufreq_driver_lock, flags);
2251 cpufreq_driver->boost_enabled = !state;
2252 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2254 pr_err("%s: Cannot %s BOOST\n", __func__,
2255 state ? "enable" : "disable");
2261 int cpufreq_boost_supported(void)
2263 if (likely(cpufreq_driver))
2264 return cpufreq_driver->boost_supported;
2268 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2270 int cpufreq_boost_enabled(void)
2272 return cpufreq_driver->boost_enabled;
2274 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2276 /*********************************************************************
2277 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2278 *********************************************************************/
2281 * cpufreq_register_driver - register a CPU Frequency driver
2282 * @driver_data: A struct cpufreq_driver containing the values#
2283 * submitted by the CPU Frequency driver.
2285 * Registers a CPU Frequency driver to this core code. This code
2286 * returns zero on success, -EBUSY when another driver got here first
2287 * (and isn't unregistered in the meantime).
2290 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2292 unsigned long flags;
2295 if (cpufreq_disabled())
2298 if (!driver_data || !driver_data->verify || !driver_data->init ||
2299 !(driver_data->setpolicy || driver_data->target_index ||
2300 driver_data->target))
2303 pr_debug("trying to register driver %s\n", driver_data->name);
2305 if (driver_data->setpolicy)
2306 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2308 write_lock_irqsave(&cpufreq_driver_lock, flags);
2309 if (cpufreq_driver) {
2310 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2313 cpufreq_driver = driver_data;
2314 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2316 if (cpufreq_boost_supported()) {
2318 * Check if driver provides function to enable boost -
2319 * if not, use cpufreq_boost_set_sw as default
2321 if (!cpufreq_driver->set_boost)
2322 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2324 ret = cpufreq_sysfs_create_file(&boost.attr);
2326 pr_err("%s: cannot register global BOOST sysfs file\n",
2328 goto err_null_driver;
2332 ret = subsys_interface_register(&cpufreq_interface);
2334 goto err_boost_unreg;
2336 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2340 /* check for at least one working CPU */
2341 for (i = 0; i < nr_cpu_ids; i++)
2342 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2347 /* if all ->init() calls failed, unregister */
2349 pr_debug("no CPU initialized for driver %s\n",
2355 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2356 pr_debug("driver %s up and running\n", driver_data->name);
2360 subsys_interface_unregister(&cpufreq_interface);
2362 if (cpufreq_boost_supported())
2363 cpufreq_sysfs_remove_file(&boost.attr);
2365 write_lock_irqsave(&cpufreq_driver_lock, flags);
2366 cpufreq_driver = NULL;
2367 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2370 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2373 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2375 * Unregister the current CPUFreq driver. Only call this if you have
2376 * the right to do so, i.e. if you have succeeded in initialising before!
2377 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2378 * currently not initialised.
2380 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2382 unsigned long flags;
2384 if (!cpufreq_driver || (driver != cpufreq_driver))
2387 pr_debug("unregistering driver %s\n", driver->name);
2389 subsys_interface_unregister(&cpufreq_interface);
2390 if (cpufreq_boost_supported())
2391 cpufreq_sysfs_remove_file(&boost.attr);
2393 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2395 down_write(&cpufreq_rwsem);
2396 write_lock_irqsave(&cpufreq_driver_lock, flags);
2398 cpufreq_driver = NULL;
2400 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2401 up_write(&cpufreq_rwsem);
2405 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2407 static int __init cpufreq_core_init(void)
2409 if (cpufreq_disabled())
2412 cpufreq_global_kobject = kobject_create();
2413 BUG_ON(!cpufreq_global_kobject);
2414 register_syscore_ops(&cpufreq_syscore_ops);
2418 core_initcall(cpufreq_core_init);