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 static 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 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
181 struct cpufreq_policy *policy = NULL;
184 if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
187 if (!down_read_trylock(&cpufreq_rwsem))
190 /* get the cpufreq driver */
191 read_lock_irqsave(&cpufreq_driver_lock, flags);
193 if (cpufreq_driver) {
195 policy = per_cpu(cpufreq_cpu_data, cpu);
197 kobject_get(&policy->kobj);
200 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
203 up_read(&cpufreq_rwsem);
207 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
209 void cpufreq_cpu_put(struct cpufreq_policy *policy)
211 if (cpufreq_disabled())
214 kobject_put(&policy->kobj);
215 up_read(&cpufreq_rwsem);
217 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
219 /*********************************************************************
220 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
221 *********************************************************************/
224 * adjust_jiffies - adjust the system "loops_per_jiffy"
226 * This function alters the system "loops_per_jiffy" for the clock
227 * speed change. Note that loops_per_jiffy cannot be updated on SMP
228 * systems as each CPU might be scaled differently. So, use the arch
229 * per-CPU loops_per_jiffy value wherever possible.
232 static unsigned long l_p_j_ref;
233 static unsigned int l_p_j_ref_freq;
235 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
237 if (ci->flags & CPUFREQ_CONST_LOOPS)
240 if (!l_p_j_ref_freq) {
241 l_p_j_ref = loops_per_jiffy;
242 l_p_j_ref_freq = ci->old;
243 pr_debug("saving %lu as reference value for loops_per_jiffy; "
244 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
246 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
247 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
248 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
250 pr_debug("scaling loops_per_jiffy to %lu "
251 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
255 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
261 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
262 struct cpufreq_freqs *freqs, unsigned int state)
264 BUG_ON(irqs_disabled());
266 if (cpufreq_disabled())
269 freqs->flags = cpufreq_driver->flags;
270 pr_debug("notification %u of frequency transition to %u kHz\n",
275 case CPUFREQ_PRECHANGE:
276 /* detect if the driver reported a value as "old frequency"
277 * which is not equal to what the cpufreq core thinks is
280 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
281 if ((policy) && (policy->cpu == freqs->cpu) &&
282 (policy->cur) && (policy->cur != freqs->old)) {
283 pr_debug("Warning: CPU frequency is"
284 " %u, cpufreq assumed %u kHz.\n",
285 freqs->old, policy->cur);
286 freqs->old = policy->cur;
289 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
290 CPUFREQ_PRECHANGE, freqs);
291 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
294 case CPUFREQ_POSTCHANGE:
295 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
296 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
297 (unsigned long)freqs->cpu);
298 trace_cpu_frequency(freqs->new, freqs->cpu);
299 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
300 CPUFREQ_POSTCHANGE, freqs);
301 if (likely(policy) && likely(policy->cpu == freqs->cpu))
302 policy->cur = freqs->new;
308 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
309 * on frequency transition.
311 * This function calls the transition notifiers and the "adjust_jiffies"
312 * function. It is called twice on all CPU frequency changes that have
315 void cpufreq_notify_transition(struct cpufreq_policy *policy,
316 struct cpufreq_freqs *freqs, unsigned int state)
318 for_each_cpu(freqs->cpu, policy->cpus)
319 __cpufreq_notify_transition(policy, freqs, state);
321 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
324 /*********************************************************************
326 *********************************************************************/
328 static struct cpufreq_governor *__find_governor(const char *str_governor)
330 struct cpufreq_governor *t;
332 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
333 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
340 * cpufreq_parse_governor - parse a governor string
342 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
343 struct cpufreq_governor **governor)
350 if (cpufreq_driver->setpolicy) {
351 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
352 *policy = CPUFREQ_POLICY_PERFORMANCE;
354 } else if (!strnicmp(str_governor, "powersave",
356 *policy = CPUFREQ_POLICY_POWERSAVE;
359 } else if (has_target()) {
360 struct cpufreq_governor *t;
362 mutex_lock(&cpufreq_governor_mutex);
364 t = __find_governor(str_governor);
369 mutex_unlock(&cpufreq_governor_mutex);
370 ret = request_module("cpufreq_%s", str_governor);
371 mutex_lock(&cpufreq_governor_mutex);
374 t = __find_governor(str_governor);
382 mutex_unlock(&cpufreq_governor_mutex);
389 * cpufreq_per_cpu_attr_read() / show_##file_name() -
390 * print out cpufreq information
392 * Write out information from cpufreq_driver->policy[cpu]; object must be
396 #define show_one(file_name, object) \
397 static ssize_t show_##file_name \
398 (struct cpufreq_policy *policy, char *buf) \
400 return sprintf(buf, "%u\n", policy->object); \
403 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
404 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
405 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
406 show_one(scaling_min_freq, min);
407 show_one(scaling_max_freq, max);
408 show_one(scaling_cur_freq, cur);
410 static int cpufreq_set_policy(struct cpufreq_policy *policy,
411 struct cpufreq_policy *new_policy);
414 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
416 #define store_one(file_name, object) \
417 static ssize_t store_##file_name \
418 (struct cpufreq_policy *policy, const char *buf, size_t count) \
421 struct cpufreq_policy new_policy; \
423 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
427 ret = sscanf(buf, "%u", &new_policy.object); \
431 ret = cpufreq_set_policy(policy, &new_policy); \
432 policy->user_policy.object = policy->object; \
434 return ret ? ret : count; \
437 store_one(scaling_min_freq, min);
438 store_one(scaling_max_freq, max);
441 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
443 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
446 unsigned int cur_freq = __cpufreq_get(policy->cpu);
448 return sprintf(buf, "<unknown>");
449 return sprintf(buf, "%u\n", cur_freq);
453 * show_scaling_governor - show the current policy for the specified CPU
455 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
457 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
458 return sprintf(buf, "powersave\n");
459 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
460 return sprintf(buf, "performance\n");
461 else if (policy->governor)
462 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
463 policy->governor->name);
468 * store_scaling_governor - store policy for the specified CPU
470 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
471 const char *buf, size_t count)
474 char str_governor[16];
475 struct cpufreq_policy new_policy;
477 ret = cpufreq_get_policy(&new_policy, policy->cpu);
481 ret = sscanf(buf, "%15s", str_governor);
485 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
486 &new_policy.governor))
489 ret = cpufreq_set_policy(policy, &new_policy);
491 policy->user_policy.policy = policy->policy;
492 policy->user_policy.governor = policy->governor;
501 * show_scaling_driver - show the cpufreq driver currently loaded
503 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
505 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
509 * show_scaling_available_governors - show the available CPUfreq governors
511 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
515 struct cpufreq_governor *t;
518 i += sprintf(buf, "performance powersave");
522 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
523 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
524 - (CPUFREQ_NAME_LEN + 2)))
526 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
529 i += sprintf(&buf[i], "\n");
533 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
538 for_each_cpu(cpu, mask) {
540 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
541 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
542 if (i >= (PAGE_SIZE - 5))
545 i += sprintf(&buf[i], "\n");
548 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
551 * show_related_cpus - show the CPUs affected by each transition even if
552 * hw coordination is in use
554 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
556 return cpufreq_show_cpus(policy->related_cpus, buf);
560 * show_affected_cpus - show the CPUs affected by each transition
562 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
564 return cpufreq_show_cpus(policy->cpus, buf);
567 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
568 const char *buf, size_t count)
570 unsigned int freq = 0;
573 if (!policy->governor || !policy->governor->store_setspeed)
576 ret = sscanf(buf, "%u", &freq);
580 policy->governor->store_setspeed(policy, freq);
585 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
587 if (!policy->governor || !policy->governor->show_setspeed)
588 return sprintf(buf, "<unsupported>\n");
590 return policy->governor->show_setspeed(policy, buf);
594 * show_bios_limit - show the current cpufreq HW/BIOS limitation
596 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
600 if (cpufreq_driver->bios_limit) {
601 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
603 return sprintf(buf, "%u\n", limit);
605 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
608 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
609 cpufreq_freq_attr_ro(cpuinfo_min_freq);
610 cpufreq_freq_attr_ro(cpuinfo_max_freq);
611 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
612 cpufreq_freq_attr_ro(scaling_available_governors);
613 cpufreq_freq_attr_ro(scaling_driver);
614 cpufreq_freq_attr_ro(scaling_cur_freq);
615 cpufreq_freq_attr_ro(bios_limit);
616 cpufreq_freq_attr_ro(related_cpus);
617 cpufreq_freq_attr_ro(affected_cpus);
618 cpufreq_freq_attr_rw(scaling_min_freq);
619 cpufreq_freq_attr_rw(scaling_max_freq);
620 cpufreq_freq_attr_rw(scaling_governor);
621 cpufreq_freq_attr_rw(scaling_setspeed);
623 static struct attribute *default_attrs[] = {
624 &cpuinfo_min_freq.attr,
625 &cpuinfo_max_freq.attr,
626 &cpuinfo_transition_latency.attr,
627 &scaling_min_freq.attr,
628 &scaling_max_freq.attr,
631 &scaling_governor.attr,
632 &scaling_driver.attr,
633 &scaling_available_governors.attr,
634 &scaling_setspeed.attr,
638 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
639 #define to_attr(a) container_of(a, struct freq_attr, attr)
641 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
643 struct cpufreq_policy *policy = to_policy(kobj);
644 struct freq_attr *fattr = to_attr(attr);
647 if (!down_read_trylock(&cpufreq_rwsem))
650 down_read(&policy->rwsem);
653 ret = fattr->show(policy, buf);
657 up_read(&policy->rwsem);
658 up_read(&cpufreq_rwsem);
663 static ssize_t store(struct kobject *kobj, struct attribute *attr,
664 const char *buf, size_t count)
666 struct cpufreq_policy *policy = to_policy(kobj);
667 struct freq_attr *fattr = to_attr(attr);
668 ssize_t ret = -EINVAL;
672 if (!cpu_online(policy->cpu))
675 if (!down_read_trylock(&cpufreq_rwsem))
678 down_write(&policy->rwsem);
681 ret = fattr->store(policy, buf, count);
685 up_write(&policy->rwsem);
687 up_read(&cpufreq_rwsem);
694 static void cpufreq_sysfs_release(struct kobject *kobj)
696 struct cpufreq_policy *policy = to_policy(kobj);
697 pr_debug("last reference is dropped\n");
698 complete(&policy->kobj_unregister);
701 static const struct sysfs_ops sysfs_ops = {
706 static struct kobj_type ktype_cpufreq = {
707 .sysfs_ops = &sysfs_ops,
708 .default_attrs = default_attrs,
709 .release = cpufreq_sysfs_release,
712 struct kobject *cpufreq_global_kobject;
713 EXPORT_SYMBOL(cpufreq_global_kobject);
715 static int cpufreq_global_kobject_usage;
717 int cpufreq_get_global_kobject(void)
719 if (!cpufreq_global_kobject_usage++)
720 return kobject_add(cpufreq_global_kobject,
721 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
725 EXPORT_SYMBOL(cpufreq_get_global_kobject);
727 void cpufreq_put_global_kobject(void)
729 if (!--cpufreq_global_kobject_usage)
730 kobject_del(cpufreq_global_kobject);
732 EXPORT_SYMBOL(cpufreq_put_global_kobject);
734 int cpufreq_sysfs_create_file(const struct attribute *attr)
736 int ret = cpufreq_get_global_kobject();
739 ret = sysfs_create_file(cpufreq_global_kobject, attr);
741 cpufreq_put_global_kobject();
746 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
748 void cpufreq_sysfs_remove_file(const struct attribute *attr)
750 sysfs_remove_file(cpufreq_global_kobject, attr);
751 cpufreq_put_global_kobject();
753 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
755 /* symlink affected CPUs */
756 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
761 for_each_cpu(j, policy->cpus) {
762 struct device *cpu_dev;
764 if (j == policy->cpu)
767 pr_debug("Adding link for CPU: %u\n", j);
768 cpu_dev = get_cpu_device(j);
769 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
777 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
780 struct freq_attr **drv_attr;
783 /* prepare interface data */
784 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
785 &dev->kobj, "cpufreq");
789 /* set up files for this cpu device */
790 drv_attr = cpufreq_driver->attr;
791 while ((drv_attr) && (*drv_attr)) {
792 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
794 goto err_out_kobj_put;
797 if (cpufreq_driver->get) {
798 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
800 goto err_out_kobj_put;
803 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
805 goto err_out_kobj_put;
807 if (cpufreq_driver->bios_limit) {
808 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
810 goto err_out_kobj_put;
813 ret = cpufreq_add_dev_symlink(policy);
815 goto err_out_kobj_put;
820 kobject_put(&policy->kobj);
821 wait_for_completion(&policy->kobj_unregister);
825 static void cpufreq_init_policy(struct cpufreq_policy *policy)
827 struct cpufreq_policy new_policy;
830 memcpy(&new_policy, policy, sizeof(*policy));
831 /* assure that the starting sequence is run in cpufreq_set_policy */
832 policy->governor = NULL;
834 /* set default policy */
835 ret = cpufreq_set_policy(policy, &new_policy);
836 policy->user_policy.policy = policy->policy;
837 policy->user_policy.governor = policy->governor;
840 pr_debug("setting policy failed\n");
841 if (cpufreq_driver->exit)
842 cpufreq_driver->exit(policy);
846 #ifdef CONFIG_HOTPLUG_CPU
847 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
848 unsigned int cpu, struct device *dev,
855 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
857 pr_err("%s: Failed to stop governor\n", __func__);
862 down_write(&policy->rwsem);
864 write_lock_irqsave(&cpufreq_driver_lock, flags);
866 cpumask_set_cpu(cpu, policy->cpus);
867 per_cpu(cpufreq_cpu_data, cpu) = policy;
868 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
870 up_write(&policy->rwsem);
873 if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||
874 (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) {
875 pr_err("%s: Failed to start governor\n", __func__);
880 /* Don't touch sysfs links during light-weight init */
882 ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
888 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
890 struct cpufreq_policy *policy;
893 read_lock_irqsave(&cpufreq_driver_lock, flags);
895 policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
897 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
902 static struct cpufreq_policy *cpufreq_policy_alloc(void)
904 struct cpufreq_policy *policy;
906 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
910 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
911 goto err_free_policy;
913 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
914 goto err_free_cpumask;
916 INIT_LIST_HEAD(&policy->policy_list);
917 init_rwsem(&policy->rwsem);
922 free_cpumask_var(policy->cpus);
929 static void cpufreq_policy_free(struct cpufreq_policy *policy)
931 free_cpumask_var(policy->related_cpus);
932 free_cpumask_var(policy->cpus);
936 static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
938 if (WARN_ON(cpu == policy->cpu))
941 down_write(&policy->rwsem);
943 policy->last_cpu = policy->cpu;
946 up_write(&policy->rwsem);
948 cpufreq_frequency_table_update_policy_cpu(policy);
949 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
950 CPUFREQ_UPDATE_POLICY_CPU, policy);
953 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
956 unsigned int j, cpu = dev->id;
958 struct cpufreq_policy *policy;
960 #ifdef CONFIG_HOTPLUG_CPU
961 struct cpufreq_policy *tpolicy;
962 struct cpufreq_governor *gov;
965 if (cpu_is_offline(cpu))
968 pr_debug("adding CPU %u\n", cpu);
971 /* check whether a different CPU already registered this
972 * CPU because it is in the same boat. */
973 policy = cpufreq_cpu_get(cpu);
974 if (unlikely(policy)) {
975 cpufreq_cpu_put(policy);
980 if (!down_read_trylock(&cpufreq_rwsem))
983 #ifdef CONFIG_HOTPLUG_CPU
984 /* Check if this cpu was hot-unplugged earlier and has siblings */
985 read_lock_irqsave(&cpufreq_driver_lock, flags);
986 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
987 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
988 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
989 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen);
990 up_read(&cpufreq_rwsem);
994 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
998 /* Restore the saved policy when doing light-weight init */
999 policy = cpufreq_policy_restore(cpu);
1001 policy = cpufreq_policy_alloc();
1008 * In the resume path, since we restore a saved policy, the assignment
1009 * to policy->cpu is like an update of the existing policy, rather than
1010 * the creation of a brand new one. So we need to perform this update
1011 * by invoking update_policy_cpu().
1013 if (frozen && cpu != policy->cpu)
1014 update_policy_cpu(policy, cpu);
1018 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
1019 cpumask_copy(policy->cpus, cpumask_of(cpu));
1021 init_completion(&policy->kobj_unregister);
1022 INIT_WORK(&policy->update, handle_update);
1024 /* call driver. From then on the cpufreq must be able
1025 * to accept all calls to ->verify and ->setpolicy for this CPU
1027 ret = cpufreq_driver->init(policy);
1029 pr_debug("initialization failed\n");
1030 goto err_set_policy_cpu;
1033 if (cpufreq_driver->get) {
1034 policy->cur = cpufreq_driver->get(policy->cpu);
1036 pr_err("%s: ->get() failed\n", __func__);
1041 /* related cpus should atleast have policy->cpus */
1042 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1045 * affected cpus must always be the one, which are online. We aren't
1046 * managing offline cpus here.
1048 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1050 policy->user_policy.min = policy->min;
1051 policy->user_policy.max = policy->max;
1053 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1054 CPUFREQ_START, policy);
1056 #ifdef CONFIG_HOTPLUG_CPU
1057 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
1059 policy->governor = gov;
1060 pr_debug("Restoring governor %s for cpu %d\n",
1061 policy->governor->name, cpu);
1065 write_lock_irqsave(&cpufreq_driver_lock, flags);
1066 for_each_cpu(j, policy->cpus)
1067 per_cpu(cpufreq_cpu_data, j) = policy;
1068 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1071 ret = cpufreq_add_dev_interface(policy, dev);
1073 goto err_out_unregister;
1076 write_lock_irqsave(&cpufreq_driver_lock, flags);
1077 list_add(&policy->policy_list, &cpufreq_policy_list);
1078 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1080 cpufreq_init_policy(policy);
1082 kobject_uevent(&policy->kobj, KOBJ_ADD);
1083 up_read(&cpufreq_rwsem);
1085 pr_debug("initialization complete\n");
1090 write_lock_irqsave(&cpufreq_driver_lock, flags);
1091 for_each_cpu(j, policy->cpus)
1092 per_cpu(cpufreq_cpu_data, j) = NULL;
1093 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1096 if (cpufreq_driver->exit)
1097 cpufreq_driver->exit(policy);
1099 cpufreq_policy_free(policy);
1101 up_read(&cpufreq_rwsem);
1107 * cpufreq_add_dev - add a CPU device
1109 * Adds the cpufreq interface for a CPU device.
1111 * The Oracle says: try running cpufreq registration/unregistration concurrently
1112 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1113 * mess up, but more thorough testing is needed. - Mathieu
1115 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1117 return __cpufreq_add_dev(dev, sif, false);
1120 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
1121 unsigned int old_cpu, bool frozen)
1123 struct device *cpu_dev;
1126 /* first sibling now owns the new sysfs dir */
1127 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
1129 /* Don't touch sysfs files during light-weight tear-down */
1133 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1134 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1136 pr_err("%s: Failed to move kobj: %d", __func__, ret);
1138 down_write(&policy->rwsem);
1139 cpumask_set_cpu(old_cpu, policy->cpus);
1140 up_write(&policy->rwsem);
1142 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1151 static int __cpufreq_remove_dev_prepare(struct device *dev,
1152 struct subsys_interface *sif,
1155 unsigned int cpu = dev->id, cpus;
1157 unsigned long flags;
1158 struct cpufreq_policy *policy;
1160 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1162 write_lock_irqsave(&cpufreq_driver_lock, flags);
1164 policy = per_cpu(cpufreq_cpu_data, cpu);
1166 /* Save the policy somewhere when doing a light-weight tear-down */
1168 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1170 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1173 pr_debug("%s: No cpu_data found\n", __func__);
1178 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1180 pr_err("%s: Failed to stop governor\n", __func__);
1185 #ifdef CONFIG_HOTPLUG_CPU
1186 if (!cpufreq_driver->setpolicy)
1187 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1188 policy->governor->name, CPUFREQ_NAME_LEN);
1191 down_read(&policy->rwsem);
1192 cpus = cpumask_weight(policy->cpus);
1193 up_read(&policy->rwsem);
1195 if (cpu != policy->cpu) {
1197 sysfs_remove_link(&dev->kobj, "cpufreq");
1198 } else if (cpus > 1) {
1199 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
1201 update_policy_cpu(policy, new_cpu);
1204 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1205 __func__, new_cpu, cpu);
1213 static int __cpufreq_remove_dev_finish(struct device *dev,
1214 struct subsys_interface *sif,
1217 unsigned int cpu = dev->id, cpus;
1219 unsigned long flags;
1220 struct cpufreq_policy *policy;
1221 struct kobject *kobj;
1222 struct completion *cmp;
1224 read_lock_irqsave(&cpufreq_driver_lock, flags);
1225 policy = per_cpu(cpufreq_cpu_data, cpu);
1226 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1229 pr_debug("%s: No cpu_data found\n", __func__);
1233 down_write(&policy->rwsem);
1234 cpus = cpumask_weight(policy->cpus);
1237 cpumask_clear_cpu(cpu, policy->cpus);
1238 up_write(&policy->rwsem);
1240 /* If cpu is last user of policy, free policy */
1243 ret = __cpufreq_governor(policy,
1244 CPUFREQ_GOV_POLICY_EXIT);
1246 pr_err("%s: Failed to exit governor\n",
1253 down_read(&policy->rwsem);
1254 kobj = &policy->kobj;
1255 cmp = &policy->kobj_unregister;
1256 up_read(&policy->rwsem);
1260 * We need to make sure that the underlying kobj is
1261 * actually not referenced anymore by anybody before we
1262 * proceed with unloading.
1264 pr_debug("waiting for dropping of refcount\n");
1265 wait_for_completion(cmp);
1266 pr_debug("wait complete\n");
1270 * Perform the ->exit() even during light-weight tear-down,
1271 * since this is a core component, and is essential for the
1272 * subsequent light-weight ->init() to succeed.
1274 if (cpufreq_driver->exit)
1275 cpufreq_driver->exit(policy);
1277 /* Remove policy from list of active policies */
1278 write_lock_irqsave(&cpufreq_driver_lock, flags);
1279 list_del(&policy->policy_list);
1280 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1283 cpufreq_policy_free(policy);
1286 if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) ||
1287 (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) {
1288 pr_err("%s: Failed to start governor\n",
1295 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1300 * cpufreq_remove_dev - remove a CPU device
1302 * Removes the cpufreq interface for a CPU device.
1304 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1306 unsigned int cpu = dev->id;
1309 if (cpu_is_offline(cpu))
1312 ret = __cpufreq_remove_dev_prepare(dev, sif, false);
1315 ret = __cpufreq_remove_dev_finish(dev, sif, false);
1320 static void handle_update(struct work_struct *work)
1322 struct cpufreq_policy *policy =
1323 container_of(work, struct cpufreq_policy, update);
1324 unsigned int cpu = policy->cpu;
1325 pr_debug("handle_update for cpu %u called\n", cpu);
1326 cpufreq_update_policy(cpu);
1330 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1333 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1334 * @new_freq: CPU frequency the CPU actually runs at
1336 * We adjust to current frequency first, and need to clean up later.
1337 * So either call to cpufreq_update_policy() or schedule handle_update()).
1339 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1340 unsigned int new_freq)
1342 struct cpufreq_policy *policy;
1343 struct cpufreq_freqs freqs;
1344 unsigned long flags;
1346 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1347 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1349 freqs.old = old_freq;
1350 freqs.new = new_freq;
1352 read_lock_irqsave(&cpufreq_driver_lock, flags);
1353 policy = per_cpu(cpufreq_cpu_data, cpu);
1354 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1356 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
1357 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
1361 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1364 * This is the last known freq, without actually getting it from the driver.
1365 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1367 unsigned int cpufreq_quick_get(unsigned int cpu)
1369 struct cpufreq_policy *policy;
1370 unsigned int ret_freq = 0;
1372 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1373 return cpufreq_driver->get(cpu);
1375 policy = cpufreq_cpu_get(cpu);
1377 ret_freq = policy->cur;
1378 cpufreq_cpu_put(policy);
1383 EXPORT_SYMBOL(cpufreq_quick_get);
1386 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1389 * Just return the max possible frequency for a given CPU.
1391 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1393 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1394 unsigned int ret_freq = 0;
1397 ret_freq = policy->max;
1398 cpufreq_cpu_put(policy);
1403 EXPORT_SYMBOL(cpufreq_quick_get_max);
1405 static unsigned int __cpufreq_get(unsigned int cpu)
1407 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1408 unsigned int ret_freq = 0;
1410 if (!cpufreq_driver->get)
1413 ret_freq = cpufreq_driver->get(cpu);
1415 if (ret_freq && policy->cur &&
1416 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1417 /* verify no discrepancy between actual and
1418 saved value exists */
1419 if (unlikely(ret_freq != policy->cur)) {
1420 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1421 schedule_work(&policy->update);
1429 * cpufreq_get - get the current CPU frequency (in kHz)
1432 * Get the CPU current (static) CPU frequency
1434 unsigned int cpufreq_get(unsigned int cpu)
1436 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1437 unsigned int ret_freq = 0;
1439 if (cpufreq_disabled() || !cpufreq_driver)
1444 if (!down_read_trylock(&cpufreq_rwsem))
1447 down_read(&policy->rwsem);
1449 ret_freq = __cpufreq_get(cpu);
1451 up_read(&policy->rwsem);
1452 up_read(&cpufreq_rwsem);
1456 EXPORT_SYMBOL(cpufreq_get);
1458 static struct subsys_interface cpufreq_interface = {
1460 .subsys = &cpu_subsys,
1461 .add_dev = cpufreq_add_dev,
1462 .remove_dev = cpufreq_remove_dev,
1466 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1468 * This function is only executed for the boot processor. The other CPUs
1469 * have been put offline by means of CPU hotplug.
1471 static int cpufreq_bp_suspend(void)
1475 int cpu = smp_processor_id();
1476 struct cpufreq_policy *policy;
1478 pr_debug("suspending cpu %u\n", cpu);
1480 /* If there's no policy for the boot CPU, we have nothing to do. */
1481 policy = cpufreq_cpu_get(cpu);
1485 if (cpufreq_driver->suspend) {
1486 ret = cpufreq_driver->suspend(policy);
1488 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1489 "step on CPU %u\n", policy->cpu);
1492 cpufreq_cpu_put(policy);
1497 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1499 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1500 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1501 * restored. It will verify that the current freq is in sync with
1502 * what we believe it to be. This is a bit later than when it
1503 * should be, but nonethteless it's better than calling
1504 * cpufreq_driver->get() here which might re-enable interrupts...
1506 * This function is only executed for the boot CPU. The other CPUs have not
1507 * been turned on yet.
1509 static void cpufreq_bp_resume(void)
1513 int cpu = smp_processor_id();
1514 struct cpufreq_policy *policy;
1516 pr_debug("resuming cpu %u\n", cpu);
1518 /* If there's no policy for the boot CPU, we have nothing to do. */
1519 policy = cpufreq_cpu_get(cpu);
1523 if (cpufreq_driver->resume) {
1524 ret = cpufreq_driver->resume(policy);
1526 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1527 "step on CPU %u\n", policy->cpu);
1532 schedule_work(&policy->update);
1535 cpufreq_cpu_put(policy);
1538 static struct syscore_ops cpufreq_syscore_ops = {
1539 .suspend = cpufreq_bp_suspend,
1540 .resume = cpufreq_bp_resume,
1544 * cpufreq_get_current_driver - return current driver's name
1546 * Return the name string of the currently loaded cpufreq driver
1549 const char *cpufreq_get_current_driver(void)
1552 return cpufreq_driver->name;
1556 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1558 /*********************************************************************
1559 * NOTIFIER LISTS INTERFACE *
1560 *********************************************************************/
1563 * cpufreq_register_notifier - register a driver with cpufreq
1564 * @nb: notifier function to register
1565 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1567 * Add a driver to one of two lists: either a list of drivers that
1568 * are notified about clock rate changes (once before and once after
1569 * the transition), or a list of drivers that are notified about
1570 * changes in cpufreq policy.
1572 * This function may sleep, and has the same return conditions as
1573 * blocking_notifier_chain_register.
1575 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1579 if (cpufreq_disabled())
1582 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1585 case CPUFREQ_TRANSITION_NOTIFIER:
1586 ret = srcu_notifier_chain_register(
1587 &cpufreq_transition_notifier_list, nb);
1589 case CPUFREQ_POLICY_NOTIFIER:
1590 ret = blocking_notifier_chain_register(
1591 &cpufreq_policy_notifier_list, nb);
1599 EXPORT_SYMBOL(cpufreq_register_notifier);
1602 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1603 * @nb: notifier block to be unregistered
1604 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1606 * Remove a driver from the CPU frequency notifier list.
1608 * This function may sleep, and has the same return conditions as
1609 * blocking_notifier_chain_unregister.
1611 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1615 if (cpufreq_disabled())
1619 case CPUFREQ_TRANSITION_NOTIFIER:
1620 ret = srcu_notifier_chain_unregister(
1621 &cpufreq_transition_notifier_list, nb);
1623 case CPUFREQ_POLICY_NOTIFIER:
1624 ret = blocking_notifier_chain_unregister(
1625 &cpufreq_policy_notifier_list, nb);
1633 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1636 /*********************************************************************
1638 *********************************************************************/
1640 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1641 unsigned int target_freq,
1642 unsigned int relation)
1644 int retval = -EINVAL;
1645 unsigned int old_target_freq = target_freq;
1647 if (cpufreq_disabled())
1650 /* Make sure that target_freq is within supported range */
1651 if (target_freq > policy->max)
1652 target_freq = policy->max;
1653 if (target_freq < policy->min)
1654 target_freq = policy->min;
1656 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1657 policy->cpu, target_freq, relation, old_target_freq);
1660 * This might look like a redundant call as we are checking it again
1661 * after finding index. But it is left intentionally for cases where
1662 * exactly same freq is called again and so we can save on few function
1665 if (target_freq == policy->cur)
1668 if (cpufreq_driver->target)
1669 retval = cpufreq_driver->target(policy, target_freq, relation);
1670 else if (cpufreq_driver->target_index) {
1671 struct cpufreq_frequency_table *freq_table;
1672 struct cpufreq_freqs freqs;
1676 freq_table = cpufreq_frequency_get_table(policy->cpu);
1677 if (unlikely(!freq_table)) {
1678 pr_err("%s: Unable to find freq_table\n", __func__);
1682 retval = cpufreq_frequency_table_target(policy, freq_table,
1683 target_freq, relation, &index);
1684 if (unlikely(retval)) {
1685 pr_err("%s: Unable to find matching freq\n", __func__);
1689 if (freq_table[index].frequency == policy->cur) {
1694 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1697 freqs.old = policy->cur;
1698 freqs.new = freq_table[index].frequency;
1701 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1702 __func__, policy->cpu, freqs.old,
1705 cpufreq_notify_transition(policy, &freqs,
1709 retval = cpufreq_driver->target_index(policy, index);
1711 pr_err("%s: Failed to change cpu frequency: %d\n",
1716 * Notify with old freq in case we failed to change
1720 freqs.new = freqs.old;
1722 cpufreq_notify_transition(policy, &freqs,
1723 CPUFREQ_POSTCHANGE);
1730 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1732 int cpufreq_driver_target(struct cpufreq_policy *policy,
1733 unsigned int target_freq,
1734 unsigned int relation)
1738 down_write(&policy->rwsem);
1740 ret = __cpufreq_driver_target(policy, target_freq, relation);
1742 up_write(&policy->rwsem);
1746 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1749 * when "event" is CPUFREQ_GOV_LIMITS
1752 static int __cpufreq_governor(struct cpufreq_policy *policy,
1757 /* Only must be defined when default governor is known to have latency
1758 restrictions, like e.g. conservative or ondemand.
1759 That this is the case is already ensured in Kconfig
1761 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1762 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1764 struct cpufreq_governor *gov = NULL;
1767 if (policy->governor->max_transition_latency &&
1768 policy->cpuinfo.transition_latency >
1769 policy->governor->max_transition_latency) {
1773 printk(KERN_WARNING "%s governor failed, too long"
1774 " transition latency of HW, fallback"
1775 " to %s governor\n",
1776 policy->governor->name,
1778 policy->governor = gov;
1782 if (event == CPUFREQ_GOV_POLICY_INIT)
1783 if (!try_module_get(policy->governor->owner))
1786 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1787 policy->cpu, event);
1789 mutex_lock(&cpufreq_governor_lock);
1790 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1791 || (!policy->governor_enabled
1792 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1793 mutex_unlock(&cpufreq_governor_lock);
1797 if (event == CPUFREQ_GOV_STOP)
1798 policy->governor_enabled = false;
1799 else if (event == CPUFREQ_GOV_START)
1800 policy->governor_enabled = true;
1802 mutex_unlock(&cpufreq_governor_lock);
1804 ret = policy->governor->governor(policy, event);
1807 if (event == CPUFREQ_GOV_POLICY_INIT)
1808 policy->governor->initialized++;
1809 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1810 policy->governor->initialized--;
1812 /* Restore original values */
1813 mutex_lock(&cpufreq_governor_lock);
1814 if (event == CPUFREQ_GOV_STOP)
1815 policy->governor_enabled = true;
1816 else if (event == CPUFREQ_GOV_START)
1817 policy->governor_enabled = false;
1818 mutex_unlock(&cpufreq_governor_lock);
1821 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
1822 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
1823 module_put(policy->governor->owner);
1828 int cpufreq_register_governor(struct cpufreq_governor *governor)
1835 if (cpufreq_disabled())
1838 mutex_lock(&cpufreq_governor_mutex);
1840 governor->initialized = 0;
1842 if (__find_governor(governor->name) == NULL) {
1844 list_add(&governor->governor_list, &cpufreq_governor_list);
1847 mutex_unlock(&cpufreq_governor_mutex);
1850 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1852 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1854 #ifdef CONFIG_HOTPLUG_CPU
1861 if (cpufreq_disabled())
1864 #ifdef CONFIG_HOTPLUG_CPU
1865 for_each_present_cpu(cpu) {
1866 if (cpu_online(cpu))
1868 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1869 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1873 mutex_lock(&cpufreq_governor_mutex);
1874 list_del(&governor->governor_list);
1875 mutex_unlock(&cpufreq_governor_mutex);
1878 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1881 /*********************************************************************
1882 * POLICY INTERFACE *
1883 *********************************************************************/
1886 * cpufreq_get_policy - get the current cpufreq_policy
1887 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1890 * Reads the current cpufreq policy.
1892 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1894 struct cpufreq_policy *cpu_policy;
1898 cpu_policy = cpufreq_cpu_get(cpu);
1902 memcpy(policy, cpu_policy, sizeof(*policy));
1904 cpufreq_cpu_put(cpu_policy);
1907 EXPORT_SYMBOL(cpufreq_get_policy);
1910 * policy : current policy.
1911 * new_policy: policy to be set.
1913 static int cpufreq_set_policy(struct cpufreq_policy *policy,
1914 struct cpufreq_policy *new_policy)
1916 int ret = 0, failed = 1;
1918 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu,
1919 new_policy->min, new_policy->max);
1921 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
1923 if (new_policy->min > policy->max || new_policy->max < policy->min) {
1928 /* verify the cpu speed can be set within this limit */
1929 ret = cpufreq_driver->verify(new_policy);
1933 /* adjust if necessary - all reasons */
1934 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1935 CPUFREQ_ADJUST, new_policy);
1937 /* adjust if necessary - hardware incompatibility*/
1938 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1939 CPUFREQ_INCOMPATIBLE, new_policy);
1942 * verify the cpu speed can be set within this limit, which might be
1943 * different to the first one
1945 ret = cpufreq_driver->verify(new_policy);
1949 /* notification of the new policy */
1950 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1951 CPUFREQ_NOTIFY, new_policy);
1953 policy->min = new_policy->min;
1954 policy->max = new_policy->max;
1956 pr_debug("new min and max freqs are %u - %u kHz\n",
1957 policy->min, policy->max);
1959 if (cpufreq_driver->setpolicy) {
1960 policy->policy = new_policy->policy;
1961 pr_debug("setting range\n");
1962 ret = cpufreq_driver->setpolicy(new_policy);
1964 if (new_policy->governor != policy->governor) {
1965 /* save old, working values */
1966 struct cpufreq_governor *old_gov = policy->governor;
1968 pr_debug("governor switch\n");
1970 /* end old governor */
1971 if (policy->governor) {
1972 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1973 up_write(&policy->rwsem);
1974 __cpufreq_governor(policy,
1975 CPUFREQ_GOV_POLICY_EXIT);
1976 down_write(&policy->rwsem);
1979 /* start new governor */
1980 policy->governor = new_policy->governor;
1981 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
1982 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
1985 up_write(&policy->rwsem);
1986 __cpufreq_governor(policy,
1987 CPUFREQ_GOV_POLICY_EXIT);
1988 down_write(&policy->rwsem);
1993 /* new governor failed, so re-start old one */
1994 pr_debug("starting governor %s failed\n",
1995 policy->governor->name);
1997 policy->governor = old_gov;
1998 __cpufreq_governor(policy,
1999 CPUFREQ_GOV_POLICY_INIT);
2000 __cpufreq_governor(policy,
2006 /* might be a policy change, too, so fall through */
2008 pr_debug("governor: change or update limits\n");
2009 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2017 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2018 * @cpu: CPU which shall be re-evaluated
2020 * Useful for policy notifiers which have different necessities
2021 * at different times.
2023 int cpufreq_update_policy(unsigned int cpu)
2025 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2026 struct cpufreq_policy new_policy;
2034 down_write(&policy->rwsem);
2036 pr_debug("updating policy for CPU %u\n", cpu);
2037 memcpy(&new_policy, policy, sizeof(*policy));
2038 new_policy.min = policy->user_policy.min;
2039 new_policy.max = policy->user_policy.max;
2040 new_policy.policy = policy->user_policy.policy;
2041 new_policy.governor = policy->user_policy.governor;
2044 * BIOS might change freq behind our back
2045 * -> ask driver for current freq and notify governors about a change
2047 if (cpufreq_driver->get) {
2048 new_policy.cur = cpufreq_driver->get(cpu);
2050 pr_debug("Driver did not initialize current freq");
2051 policy->cur = new_policy.cur;
2053 if (policy->cur != new_policy.cur && has_target())
2054 cpufreq_out_of_sync(cpu, policy->cur,
2059 ret = cpufreq_set_policy(policy, &new_policy);
2061 up_write(&policy->rwsem);
2063 cpufreq_cpu_put(policy);
2067 EXPORT_SYMBOL(cpufreq_update_policy);
2069 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2070 unsigned long action, void *hcpu)
2072 unsigned int cpu = (unsigned long)hcpu;
2074 bool frozen = false;
2076 dev = get_cpu_device(cpu);
2079 if (action & CPU_TASKS_FROZEN)
2082 switch (action & ~CPU_TASKS_FROZEN) {
2084 __cpufreq_add_dev(dev, NULL, frozen);
2085 cpufreq_update_policy(cpu);
2088 case CPU_DOWN_PREPARE:
2089 __cpufreq_remove_dev_prepare(dev, NULL, frozen);
2093 __cpufreq_remove_dev_finish(dev, NULL, frozen);
2096 case CPU_DOWN_FAILED:
2097 __cpufreq_add_dev(dev, NULL, frozen);
2104 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2105 .notifier_call = cpufreq_cpu_callback,
2108 /*********************************************************************
2109 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2110 *********************************************************************/
2113 * cpufreq_register_driver - register a CPU Frequency driver
2114 * @driver_data: A struct cpufreq_driver containing the values#
2115 * submitted by the CPU Frequency driver.
2117 * Registers a CPU Frequency driver to this core code. This code
2118 * returns zero on success, -EBUSY when another driver got here first
2119 * (and isn't unregistered in the meantime).
2122 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2124 unsigned long flags;
2127 if (cpufreq_disabled())
2130 if (!driver_data || !driver_data->verify || !driver_data->init ||
2131 !(driver_data->setpolicy || driver_data->target_index ||
2132 driver_data->target))
2135 pr_debug("trying to register driver %s\n", driver_data->name);
2137 if (driver_data->setpolicy)
2138 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2140 write_lock_irqsave(&cpufreq_driver_lock, flags);
2141 if (cpufreq_driver) {
2142 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2145 cpufreq_driver = driver_data;
2146 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2148 ret = subsys_interface_register(&cpufreq_interface);
2150 goto err_null_driver;
2152 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2156 /* check for at least one working CPU */
2157 for (i = 0; i < nr_cpu_ids; i++)
2158 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2163 /* if all ->init() calls failed, unregister */
2165 pr_debug("no CPU initialized for driver %s\n",
2171 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2172 pr_debug("driver %s up and running\n", driver_data->name);
2176 subsys_interface_unregister(&cpufreq_interface);
2178 write_lock_irqsave(&cpufreq_driver_lock, flags);
2179 cpufreq_driver = NULL;
2180 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2183 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2186 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2188 * Unregister the current CPUFreq driver. Only call this if you have
2189 * the right to do so, i.e. if you have succeeded in initialising before!
2190 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2191 * currently not initialised.
2193 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2195 unsigned long flags;
2197 if (!cpufreq_driver || (driver != cpufreq_driver))
2200 pr_debug("unregistering driver %s\n", driver->name);
2202 subsys_interface_unregister(&cpufreq_interface);
2203 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2205 down_write(&cpufreq_rwsem);
2206 write_lock_irqsave(&cpufreq_driver_lock, flags);
2208 cpufreq_driver = NULL;
2210 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2211 up_write(&cpufreq_rwsem);
2215 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2217 static int __init cpufreq_core_init(void)
2219 if (cpufreq_disabled())
2222 cpufreq_global_kobject = kobject_create();
2223 BUG_ON(!cpufreq_global_kobject);
2224 register_syscore_ops(&cpufreq_syscore_ops);
2228 core_initcall(cpufreq_core_init);