2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/cpu.h>
21 #include <linux/cpufreq.h>
22 #include <linux/delay.h>
23 #include <linux/device.h>
24 #include <linux/init.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/suspend.h>
30 #include <linux/syscore_ops.h>
31 #include <linux/tick.h>
32 #include <trace/events/power.h>
34 static LIST_HEAD(cpufreq_policy_list);
36 static inline bool policy_is_inactive(struct cpufreq_policy *policy)
38 return cpumask_empty(policy->cpus);
41 static bool suitable_policy(struct cpufreq_policy *policy, bool active)
43 return active == !policy_is_inactive(policy);
46 /* Finds Next Acive/Inactive policy */
47 static struct cpufreq_policy *next_policy(struct cpufreq_policy *policy,
51 policy = list_next_entry(policy, policy_list);
53 /* No more policies in the list */
54 if (&policy->policy_list == &cpufreq_policy_list)
56 } while (!suitable_policy(policy, active));
61 static struct cpufreq_policy *first_policy(bool active)
63 struct cpufreq_policy *policy;
65 /* No policies in the list */
66 if (list_empty(&cpufreq_policy_list))
69 policy = list_first_entry(&cpufreq_policy_list, typeof(*policy),
72 if (!suitable_policy(policy, active))
73 policy = next_policy(policy, active);
78 /* Macros to iterate over CPU policies */
79 #define for_each_suitable_policy(__policy, __active) \
80 for (__policy = first_policy(__active); \
82 __policy = next_policy(__policy, __active))
84 #define for_each_active_policy(__policy) \
85 for_each_suitable_policy(__policy, true)
86 #define for_each_inactive_policy(__policy) \
87 for_each_suitable_policy(__policy, false)
89 #define for_each_policy(__policy) \
90 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
92 /* Iterate over governors */
93 static LIST_HEAD(cpufreq_governor_list);
94 #define for_each_governor(__governor) \
95 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
98 * The "cpufreq driver" - the arch- or hardware-dependent low
99 * level driver of CPUFreq support, and its spinlock. This lock
100 * also protects the cpufreq_cpu_data array.
102 static struct cpufreq_driver *cpufreq_driver;
103 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
104 static DEFINE_RWLOCK(cpufreq_driver_lock);
105 DEFINE_MUTEX(cpufreq_governor_lock);
107 /* Flag to suspend/resume CPUFreq governors */
108 static bool cpufreq_suspended;
110 static inline bool has_target(void)
112 return cpufreq_driver->target_index || cpufreq_driver->target;
116 * rwsem to guarantee that cpufreq driver module doesn't unload during critical
119 static DECLARE_RWSEM(cpufreq_rwsem);
121 /* internal prototypes */
122 static int __cpufreq_governor(struct cpufreq_policy *policy,
124 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
125 static void handle_update(struct work_struct *work);
128 * Two notifier lists: the "policy" list is involved in the
129 * validation process for a new CPU frequency policy; the
130 * "transition" list for kernel code that needs to handle
131 * changes to devices when the CPU clock speed changes.
132 * The mutex locks both lists.
134 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
135 static struct srcu_notifier_head cpufreq_transition_notifier_list;
137 static bool init_cpufreq_transition_notifier_list_called;
138 static int __init init_cpufreq_transition_notifier_list(void)
140 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
141 init_cpufreq_transition_notifier_list_called = true;
144 pure_initcall(init_cpufreq_transition_notifier_list);
146 static int off __read_mostly;
147 static int cpufreq_disabled(void)
151 void disable_cpufreq(void)
155 static DEFINE_MUTEX(cpufreq_governor_mutex);
157 bool have_governor_per_policy(void)
159 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
161 EXPORT_SYMBOL_GPL(have_governor_per_policy);
163 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
165 if (have_governor_per_policy())
166 return &policy->kobj;
168 return cpufreq_global_kobject;
170 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
172 struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu)
174 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
176 return policy && !policy_is_inactive(policy) ?
177 policy->freq_table : NULL;
179 EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table);
181 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
187 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
189 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
190 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
191 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
192 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
193 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
194 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
196 idle_time = cur_wall_time - busy_time;
198 *wall = cputime_to_usecs(cur_wall_time);
200 return cputime_to_usecs(idle_time);
203 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
205 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
207 if (idle_time == -1ULL)
208 return get_cpu_idle_time_jiffy(cpu, wall);
210 idle_time += get_cpu_iowait_time_us(cpu, wall);
214 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
217 * This is a generic cpufreq init() routine which can be used by cpufreq
218 * drivers of SMP systems. It will do following:
219 * - validate & show freq table passed
220 * - set policies transition latency
221 * - policy->cpus with all possible CPUs
223 int cpufreq_generic_init(struct cpufreq_policy *policy,
224 struct cpufreq_frequency_table *table,
225 unsigned int transition_latency)
229 ret = cpufreq_table_validate_and_show(policy, table);
231 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
235 policy->cpuinfo.transition_latency = transition_latency;
238 * The driver only supports the SMP configuration where all processors
239 * share the clock and voltage and clock.
241 cpumask_setall(policy->cpus);
245 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
247 /* Only for cpufreq core internal use */
248 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
250 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
252 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
255 unsigned int cpufreq_generic_get(unsigned int cpu)
257 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
259 if (!policy || IS_ERR(policy->clk)) {
260 pr_err("%s: No %s associated to cpu: %d\n",
261 __func__, policy ? "clk" : "policy", cpu);
265 return clk_get_rate(policy->clk) / 1000;
267 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
270 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
272 * @cpu: cpu to find policy for.
274 * This returns policy for 'cpu', returns NULL if it doesn't exist.
275 * It also increments the kobject reference count to mark it busy and so would
276 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
277 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
278 * freed as that depends on the kobj count.
280 * It also takes a read-lock of 'cpufreq_rwsem' and doesn't put it back if a
281 * valid policy is found. This is done to make sure the driver doesn't get
282 * unregistered while the policy is being used.
284 * Return: A valid policy on success, otherwise NULL on failure.
286 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
288 struct cpufreq_policy *policy = NULL;
291 if (WARN_ON(cpu >= nr_cpu_ids))
294 if (!down_read_trylock(&cpufreq_rwsem))
297 /* get the cpufreq driver */
298 read_lock_irqsave(&cpufreq_driver_lock, flags);
300 if (cpufreq_driver) {
302 policy = cpufreq_cpu_get_raw(cpu);
304 kobject_get(&policy->kobj);
307 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
310 up_read(&cpufreq_rwsem);
314 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
317 * cpufreq_cpu_put: Decrements the usage count of a policy
319 * @policy: policy earlier returned by cpufreq_cpu_get().
321 * This decrements the kobject reference count incremented earlier by calling
324 * It also drops the read-lock of 'cpufreq_rwsem' taken at cpufreq_cpu_get().
326 void cpufreq_cpu_put(struct cpufreq_policy *policy)
328 kobject_put(&policy->kobj);
329 up_read(&cpufreq_rwsem);
331 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
333 /*********************************************************************
334 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
335 *********************************************************************/
338 * adjust_jiffies - adjust the system "loops_per_jiffy"
340 * This function alters the system "loops_per_jiffy" for the clock
341 * speed change. Note that loops_per_jiffy cannot be updated on SMP
342 * systems as each CPU might be scaled differently. So, use the arch
343 * per-CPU loops_per_jiffy value wherever possible.
345 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
348 static unsigned long l_p_j_ref;
349 static unsigned int l_p_j_ref_freq;
351 if (ci->flags & CPUFREQ_CONST_LOOPS)
354 if (!l_p_j_ref_freq) {
355 l_p_j_ref = loops_per_jiffy;
356 l_p_j_ref_freq = ci->old;
357 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
358 l_p_j_ref, l_p_j_ref_freq);
360 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
361 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
363 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
364 loops_per_jiffy, ci->new);
369 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
370 struct cpufreq_freqs *freqs, unsigned int state)
372 BUG_ON(irqs_disabled());
374 if (cpufreq_disabled())
377 freqs->flags = cpufreq_driver->flags;
378 pr_debug("notification %u of frequency transition to %u kHz\n",
383 case CPUFREQ_PRECHANGE:
384 /* detect if the driver reported a value as "old frequency"
385 * which is not equal to what the cpufreq core thinks is
388 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
389 if ((policy) && (policy->cpu == freqs->cpu) &&
390 (policy->cur) && (policy->cur != freqs->old)) {
391 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
392 freqs->old, policy->cur);
393 freqs->old = policy->cur;
396 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
397 CPUFREQ_PRECHANGE, freqs);
398 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
401 case CPUFREQ_POSTCHANGE:
402 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
403 pr_debug("FREQ: %lu - CPU: %lu\n",
404 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
405 trace_cpu_frequency(freqs->new, freqs->cpu);
406 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
407 CPUFREQ_POSTCHANGE, freqs);
408 if (likely(policy) && likely(policy->cpu == freqs->cpu))
409 policy->cur = freqs->new;
415 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
416 * on frequency transition.
418 * This function calls the transition notifiers and the "adjust_jiffies"
419 * function. It is called twice on all CPU frequency changes that have
422 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
423 struct cpufreq_freqs *freqs, unsigned int state)
425 for_each_cpu(freqs->cpu, policy->cpus)
426 __cpufreq_notify_transition(policy, freqs, state);
429 /* Do post notifications when there are chances that transition has failed */
430 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
431 struct cpufreq_freqs *freqs, int transition_failed)
433 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
434 if (!transition_failed)
437 swap(freqs->old, freqs->new);
438 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
439 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
442 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
443 struct cpufreq_freqs *freqs)
447 * Catch double invocations of _begin() which lead to self-deadlock.
448 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
449 * doesn't invoke _begin() on their behalf, and hence the chances of
450 * double invocations are very low. Moreover, there are scenarios
451 * where these checks can emit false-positive warnings in these
452 * drivers; so we avoid that by skipping them altogether.
454 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
455 && current == policy->transition_task);
458 wait_event(policy->transition_wait, !policy->transition_ongoing);
460 spin_lock(&policy->transition_lock);
462 if (unlikely(policy->transition_ongoing)) {
463 spin_unlock(&policy->transition_lock);
467 policy->transition_ongoing = true;
468 policy->transition_task = current;
470 spin_unlock(&policy->transition_lock);
472 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
474 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
476 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
477 struct cpufreq_freqs *freqs, int transition_failed)
479 if (unlikely(WARN_ON(!policy->transition_ongoing)))
482 cpufreq_notify_post_transition(policy, freqs, transition_failed);
484 policy->transition_ongoing = false;
485 policy->transition_task = NULL;
487 wake_up(&policy->transition_wait);
489 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
492 /*********************************************************************
494 *********************************************************************/
495 static ssize_t show_boost(struct kobject *kobj,
496 struct attribute *attr, char *buf)
498 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
501 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
502 const char *buf, size_t count)
506 ret = sscanf(buf, "%d", &enable);
507 if (ret != 1 || enable < 0 || enable > 1)
510 if (cpufreq_boost_trigger_state(enable)) {
511 pr_err("%s: Cannot %s BOOST!\n",
512 __func__, enable ? "enable" : "disable");
516 pr_debug("%s: cpufreq BOOST %s\n",
517 __func__, enable ? "enabled" : "disabled");
521 define_one_global_rw(boost);
523 static struct cpufreq_governor *find_governor(const char *str_governor)
525 struct cpufreq_governor *t;
528 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
535 * cpufreq_parse_governor - parse a governor string
537 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
538 struct cpufreq_governor **governor)
545 if (cpufreq_driver->setpolicy) {
546 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
547 *policy = CPUFREQ_POLICY_PERFORMANCE;
549 } else if (!strncasecmp(str_governor, "powersave",
551 *policy = CPUFREQ_POLICY_POWERSAVE;
555 struct cpufreq_governor *t;
557 mutex_lock(&cpufreq_governor_mutex);
559 t = find_governor(str_governor);
564 mutex_unlock(&cpufreq_governor_mutex);
565 ret = request_module("cpufreq_%s", str_governor);
566 mutex_lock(&cpufreq_governor_mutex);
569 t = find_governor(str_governor);
577 mutex_unlock(&cpufreq_governor_mutex);
584 * cpufreq_per_cpu_attr_read() / show_##file_name() -
585 * print out cpufreq information
587 * Write out information from cpufreq_driver->policy[cpu]; object must be
591 #define show_one(file_name, object) \
592 static ssize_t show_##file_name \
593 (struct cpufreq_policy *policy, char *buf) \
595 return sprintf(buf, "%u\n", policy->object); \
598 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
599 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
600 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
601 show_one(scaling_min_freq, min);
602 show_one(scaling_max_freq, max);
604 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
608 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
609 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
611 ret = sprintf(buf, "%u\n", policy->cur);
615 static int cpufreq_set_policy(struct cpufreq_policy *policy,
616 struct cpufreq_policy *new_policy);
619 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
621 #define store_one(file_name, object) \
622 static ssize_t store_##file_name \
623 (struct cpufreq_policy *policy, const char *buf, size_t count) \
626 struct cpufreq_policy new_policy; \
628 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
632 ret = sscanf(buf, "%u", &new_policy.object); \
636 temp = new_policy.object; \
637 ret = cpufreq_set_policy(policy, &new_policy); \
639 policy->user_policy.object = temp; \
641 return ret ? ret : count; \
644 store_one(scaling_min_freq, min);
645 store_one(scaling_max_freq, max);
648 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
650 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
653 unsigned int cur_freq = __cpufreq_get(policy);
655 return sprintf(buf, "<unknown>");
656 return sprintf(buf, "%u\n", cur_freq);
660 * show_scaling_governor - show the current policy for the specified CPU
662 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
664 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
665 return sprintf(buf, "powersave\n");
666 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
667 return sprintf(buf, "performance\n");
668 else if (policy->governor)
669 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
670 policy->governor->name);
675 * store_scaling_governor - store policy for the specified CPU
677 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
678 const char *buf, size_t count)
681 char str_governor[16];
682 struct cpufreq_policy new_policy;
684 ret = cpufreq_get_policy(&new_policy, policy->cpu);
688 ret = sscanf(buf, "%15s", str_governor);
692 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
693 &new_policy.governor))
696 ret = cpufreq_set_policy(policy, &new_policy);
698 policy->user_policy.policy = policy->policy;
699 policy->user_policy.governor = policy->governor;
708 * show_scaling_driver - show the cpufreq driver currently loaded
710 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
712 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
716 * show_scaling_available_governors - show the available CPUfreq governors
718 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
722 struct cpufreq_governor *t;
725 i += sprintf(buf, "performance powersave");
729 for_each_governor(t) {
730 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
731 - (CPUFREQ_NAME_LEN + 2)))
733 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
736 i += sprintf(&buf[i], "\n");
740 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
745 for_each_cpu(cpu, mask) {
747 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
748 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
749 if (i >= (PAGE_SIZE - 5))
752 i += sprintf(&buf[i], "\n");
755 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
758 * show_related_cpus - show the CPUs affected by each transition even if
759 * hw coordination is in use
761 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
763 return cpufreq_show_cpus(policy->related_cpus, buf);
767 * show_affected_cpus - show the CPUs affected by each transition
769 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
771 return cpufreq_show_cpus(policy->cpus, buf);
774 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
775 const char *buf, size_t count)
777 unsigned int freq = 0;
780 if (!policy->governor || !policy->governor->store_setspeed)
783 ret = sscanf(buf, "%u", &freq);
787 policy->governor->store_setspeed(policy, freq);
792 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
794 if (!policy->governor || !policy->governor->show_setspeed)
795 return sprintf(buf, "<unsupported>\n");
797 return policy->governor->show_setspeed(policy, buf);
801 * show_bios_limit - show the current cpufreq HW/BIOS limitation
803 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
807 if (cpufreq_driver->bios_limit) {
808 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
810 return sprintf(buf, "%u\n", limit);
812 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
815 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
816 cpufreq_freq_attr_ro(cpuinfo_min_freq);
817 cpufreq_freq_attr_ro(cpuinfo_max_freq);
818 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
819 cpufreq_freq_attr_ro(scaling_available_governors);
820 cpufreq_freq_attr_ro(scaling_driver);
821 cpufreq_freq_attr_ro(scaling_cur_freq);
822 cpufreq_freq_attr_ro(bios_limit);
823 cpufreq_freq_attr_ro(related_cpus);
824 cpufreq_freq_attr_ro(affected_cpus);
825 cpufreq_freq_attr_rw(scaling_min_freq);
826 cpufreq_freq_attr_rw(scaling_max_freq);
827 cpufreq_freq_attr_rw(scaling_governor);
828 cpufreq_freq_attr_rw(scaling_setspeed);
830 static struct attribute *default_attrs[] = {
831 &cpuinfo_min_freq.attr,
832 &cpuinfo_max_freq.attr,
833 &cpuinfo_transition_latency.attr,
834 &scaling_min_freq.attr,
835 &scaling_max_freq.attr,
838 &scaling_governor.attr,
839 &scaling_driver.attr,
840 &scaling_available_governors.attr,
841 &scaling_setspeed.attr,
845 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
846 #define to_attr(a) container_of(a, struct freq_attr, attr)
848 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
850 struct cpufreq_policy *policy = to_policy(kobj);
851 struct freq_attr *fattr = to_attr(attr);
854 if (!down_read_trylock(&cpufreq_rwsem))
857 down_read(&policy->rwsem);
860 ret = fattr->show(policy, buf);
864 up_read(&policy->rwsem);
865 up_read(&cpufreq_rwsem);
870 static ssize_t store(struct kobject *kobj, struct attribute *attr,
871 const char *buf, size_t count)
873 struct cpufreq_policy *policy = to_policy(kobj);
874 struct freq_attr *fattr = to_attr(attr);
875 ssize_t ret = -EINVAL;
879 if (!cpu_online(policy->cpu))
882 if (!down_read_trylock(&cpufreq_rwsem))
885 down_write(&policy->rwsem);
887 /* Updating inactive policies is invalid, so avoid doing that. */
888 if (unlikely(policy_is_inactive(policy))) {
890 goto unlock_policy_rwsem;
894 ret = fattr->store(policy, buf, count);
899 up_write(&policy->rwsem);
901 up_read(&cpufreq_rwsem);
908 static void cpufreq_sysfs_release(struct kobject *kobj)
910 struct cpufreq_policy *policy = to_policy(kobj);
911 pr_debug("last reference is dropped\n");
912 complete(&policy->kobj_unregister);
915 static const struct sysfs_ops sysfs_ops = {
920 static struct kobj_type ktype_cpufreq = {
921 .sysfs_ops = &sysfs_ops,
922 .default_attrs = default_attrs,
923 .release = cpufreq_sysfs_release,
926 struct kobject *cpufreq_global_kobject;
927 EXPORT_SYMBOL(cpufreq_global_kobject);
929 static int cpufreq_global_kobject_usage;
931 int cpufreq_get_global_kobject(void)
933 if (!cpufreq_global_kobject_usage++)
934 return kobject_add(cpufreq_global_kobject,
935 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
939 EXPORT_SYMBOL(cpufreq_get_global_kobject);
941 void cpufreq_put_global_kobject(void)
943 if (!--cpufreq_global_kobject_usage)
944 kobject_del(cpufreq_global_kobject);
946 EXPORT_SYMBOL(cpufreq_put_global_kobject);
948 int cpufreq_sysfs_create_file(const struct attribute *attr)
950 int ret = cpufreq_get_global_kobject();
953 ret = sysfs_create_file(cpufreq_global_kobject, attr);
955 cpufreq_put_global_kobject();
960 EXPORT_SYMBOL(cpufreq_sysfs_create_file);
962 void cpufreq_sysfs_remove_file(const struct attribute *attr)
964 sysfs_remove_file(cpufreq_global_kobject, attr);
965 cpufreq_put_global_kobject();
967 EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
969 static int add_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
971 struct device *cpu_dev;
973 pr_debug("%s: Adding symlink for CPU: %u\n", __func__, cpu);
978 cpu_dev = get_cpu_device(cpu);
979 if (WARN_ON(!cpu_dev))
982 return sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq");
985 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu)
987 struct device *cpu_dev;
989 pr_debug("%s: Removing symlink for CPU: %u\n", __func__, cpu);
991 cpu_dev = get_cpu_device(cpu);
992 if (WARN_ON(!cpu_dev))
995 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
998 /* Add/remove symlinks for all related CPUs */
999 static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
1004 /* Some related CPUs might not be present (physically hotplugged) */
1005 for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
1006 if (j == policy->kobj_cpu)
1009 ret = add_cpu_dev_symlink(policy, j);
1017 static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
1021 /* Some related CPUs might not be present (physically hotplugged) */
1022 for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
1023 if (j == policy->kobj_cpu)
1026 remove_cpu_dev_symlink(policy, j);
1030 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
1033 struct freq_attr **drv_attr;
1036 /* set up files for this cpu device */
1037 drv_attr = cpufreq_driver->attr;
1038 while (drv_attr && *drv_attr) {
1039 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1044 if (cpufreq_driver->get) {
1045 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1050 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1054 if (cpufreq_driver->bios_limit) {
1055 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1060 return cpufreq_add_dev_symlink(policy);
1063 static void cpufreq_init_policy(struct cpufreq_policy *policy)
1065 struct cpufreq_governor *gov = NULL;
1066 struct cpufreq_policy new_policy;
1069 memcpy(&new_policy, policy, sizeof(*policy));
1071 /* Update governor of new_policy to the governor used before hotplug */
1072 gov = find_governor(policy->last_governor);
1074 pr_debug("Restoring governor %s for cpu %d\n",
1075 policy->governor->name, policy->cpu);
1077 gov = CPUFREQ_DEFAULT_GOVERNOR;
1079 new_policy.governor = gov;
1081 /* Use the default policy if its valid. */
1082 if (cpufreq_driver->setpolicy)
1083 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
1085 /* set default policy */
1086 ret = cpufreq_set_policy(policy, &new_policy);
1088 pr_debug("setting policy failed\n");
1089 if (cpufreq_driver->exit)
1090 cpufreq_driver->exit(policy);
1094 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
1095 unsigned int cpu, struct device *dev)
1099 /* Has this CPU been taken care of already? */
1100 if (cpumask_test_cpu(cpu, policy->cpus))
1104 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1106 pr_err("%s: Failed to stop governor\n", __func__);
1111 down_write(&policy->rwsem);
1112 cpumask_set_cpu(cpu, policy->cpus);
1113 up_write(&policy->rwsem);
1116 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1118 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1121 pr_err("%s: Failed to start governor\n", __func__);
1129 static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
1131 struct cpufreq_policy *policy;
1132 unsigned long flags;
1134 read_lock_irqsave(&cpufreq_driver_lock, flags);
1135 policy = per_cpu(cpufreq_cpu_data, cpu);
1136 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1138 if (likely(policy)) {
1139 /* Policy should be inactive here */
1140 WARN_ON(!policy_is_inactive(policy));
1142 down_write(&policy->rwsem);
1144 policy->governor = NULL;
1145 up_write(&policy->rwsem);
1151 static struct cpufreq_policy *cpufreq_policy_alloc(struct device *dev)
1153 struct cpufreq_policy *policy;
1156 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1160 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1161 goto err_free_policy;
1163 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1164 goto err_free_cpumask;
1166 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
1169 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1170 goto err_free_rcpumask;
1173 INIT_LIST_HEAD(&policy->policy_list);
1174 init_rwsem(&policy->rwsem);
1175 spin_lock_init(&policy->transition_lock);
1176 init_waitqueue_head(&policy->transition_wait);
1177 init_completion(&policy->kobj_unregister);
1178 INIT_WORK(&policy->update, handle_update);
1180 policy->cpu = dev->id;
1182 /* Set this once on allocation */
1183 policy->kobj_cpu = dev->id;
1188 free_cpumask_var(policy->related_cpus);
1190 free_cpumask_var(policy->cpus);
1197 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1199 struct kobject *kobj;
1200 struct completion *cmp;
1203 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1204 CPUFREQ_REMOVE_POLICY, policy);
1206 down_write(&policy->rwsem);
1207 cpufreq_remove_dev_symlink(policy);
1208 kobj = &policy->kobj;
1209 cmp = &policy->kobj_unregister;
1210 up_write(&policy->rwsem);
1214 * We need to make sure that the underlying kobj is
1215 * actually not referenced anymore by anybody before we
1216 * proceed with unloading.
1218 pr_debug("waiting for dropping of refcount\n");
1219 wait_for_completion(cmp);
1220 pr_debug("wait complete\n");
1223 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1225 unsigned long flags;
1228 /* Remove policy from list */
1229 write_lock_irqsave(&cpufreq_driver_lock, flags);
1230 list_del(&policy->policy_list);
1232 for_each_cpu(cpu, policy->related_cpus)
1233 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1234 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1236 cpufreq_policy_put_kobj(policy, notify);
1237 free_cpumask_var(policy->related_cpus);
1238 free_cpumask_var(policy->cpus);
1243 * cpufreq_add_dev - add a CPU device
1245 * Adds the cpufreq interface for a CPU device.
1247 * The Oracle says: try running cpufreq registration/unregistration concurrently
1248 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1249 * mess up, but more thorough testing is needed. - Mathieu
1251 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1253 unsigned int j, cpu = dev->id;
1255 struct cpufreq_policy *policy;
1256 unsigned long flags;
1257 bool recover_policy = !sif;
1259 pr_debug("adding CPU %u\n", cpu);
1262 * Only possible if 'cpu' wasn't physically present earlier and we are
1263 * here from subsys_interface add callback. A hotplug notifier will
1264 * follow and we will handle it like logical CPU hotplug then. For now,
1265 * just create the sysfs link.
1267 if (cpu_is_offline(cpu))
1268 return add_cpu_dev_symlink(per_cpu(cpufreq_cpu_data, cpu), cpu);
1270 if (!down_read_trylock(&cpufreq_rwsem))
1273 /* Check if this CPU already has a policy to manage it */
1274 policy = per_cpu(cpufreq_cpu_data, cpu);
1275 if (policy && !policy_is_inactive(policy)) {
1276 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1277 ret = cpufreq_add_policy_cpu(policy, cpu, dev);
1278 up_read(&cpufreq_rwsem);
1283 * Restore the saved policy when doing light-weight init and fall back
1284 * to the full init if that fails.
1286 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1288 recover_policy = false;
1289 policy = cpufreq_policy_alloc(dev);
1294 cpumask_copy(policy->cpus, cpumask_of(cpu));
1296 /* call driver. From then on the cpufreq must be able
1297 * to accept all calls to ->verify and ->setpolicy for this CPU
1299 ret = cpufreq_driver->init(policy);
1301 pr_debug("initialization failed\n");
1302 goto err_set_policy_cpu;
1305 down_write(&policy->rwsem);
1307 /* related cpus should atleast have policy->cpus */
1308 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1311 * affected cpus must always be the one, which are online. We aren't
1312 * managing offline cpus here.
1314 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1316 if (!recover_policy) {
1317 policy->user_policy.min = policy->min;
1318 policy->user_policy.max = policy->max;
1320 write_lock_irqsave(&cpufreq_driver_lock, flags);
1321 for_each_cpu(j, policy->related_cpus)
1322 per_cpu(cpufreq_cpu_data, j) = policy;
1323 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1326 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1327 policy->cur = cpufreq_driver->get(policy->cpu);
1329 pr_err("%s: ->get() failed\n", __func__);
1335 * Sometimes boot loaders set CPU frequency to a value outside of
1336 * frequency table present with cpufreq core. In such cases CPU might be
1337 * unstable if it has to run on that frequency for long duration of time
1338 * and so its better to set it to a frequency which is specified in
1339 * freq-table. This also makes cpufreq stats inconsistent as
1340 * cpufreq-stats would fail to register because current frequency of CPU
1341 * isn't found in freq-table.
1343 * Because we don't want this change to effect boot process badly, we go
1344 * for the next freq which is >= policy->cur ('cur' must be set by now,
1345 * otherwise we will end up setting freq to lowest of the table as 'cur'
1346 * is initialized to zero).
1348 * We are passing target-freq as "policy->cur - 1" otherwise
1349 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1350 * equal to target-freq.
1352 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1354 /* Are we running at unknown frequency ? */
1355 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1356 if (ret == -EINVAL) {
1357 /* Warn user and fix it */
1358 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1359 __func__, policy->cpu, policy->cur);
1360 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1361 CPUFREQ_RELATION_L);
1364 * Reaching here after boot in a few seconds may not
1365 * mean that system will remain stable at "unknown"
1366 * frequency for longer duration. Hence, a BUG_ON().
1369 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1370 __func__, policy->cpu, policy->cur);
1374 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1375 CPUFREQ_START, policy);
1377 if (!recover_policy) {
1378 ret = cpufreq_add_dev_interface(policy, dev);
1380 goto err_out_unregister;
1381 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1382 CPUFREQ_CREATE_POLICY, policy);
1384 write_lock_irqsave(&cpufreq_driver_lock, flags);
1385 list_add(&policy->policy_list, &cpufreq_policy_list);
1386 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1389 cpufreq_init_policy(policy);
1391 if (!recover_policy) {
1392 policy->user_policy.policy = policy->policy;
1393 policy->user_policy.governor = policy->governor;
1395 up_write(&policy->rwsem);
1397 kobject_uevent(&policy->kobj, KOBJ_ADD);
1399 up_read(&cpufreq_rwsem);
1401 /* Callback for handling stuff after policy is ready */
1402 if (cpufreq_driver->ready)
1403 cpufreq_driver->ready(policy);
1405 pr_debug("initialization complete\n");
1411 up_write(&policy->rwsem);
1413 if (cpufreq_driver->exit)
1414 cpufreq_driver->exit(policy);
1416 cpufreq_policy_free(policy, recover_policy);
1418 up_read(&cpufreq_rwsem);
1423 static int __cpufreq_remove_dev_prepare(struct device *dev,
1424 struct subsys_interface *sif)
1426 unsigned int cpu = dev->id;
1428 struct cpufreq_policy *policy;
1430 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1432 policy = cpufreq_cpu_get_raw(cpu);
1434 pr_debug("%s: No cpu_data found\n", __func__);
1439 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1441 pr_err("%s: Failed to stop governor\n", __func__);
1446 down_write(&policy->rwsem);
1447 cpumask_clear_cpu(cpu, policy->cpus);
1449 if (policy_is_inactive(policy)) {
1451 strncpy(policy->last_governor, policy->governor->name,
1453 } else if (cpu == policy->cpu) {
1454 /* Nominate new CPU */
1455 policy->cpu = cpumask_any(policy->cpus);
1457 up_write(&policy->rwsem);
1459 /* Start governor again for active policy */
1460 if (!policy_is_inactive(policy)) {
1462 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1464 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1467 pr_err("%s: Failed to start governor\n", __func__);
1469 } else if (cpufreq_driver->stop_cpu) {
1470 cpufreq_driver->stop_cpu(policy);
1476 static int __cpufreq_remove_dev_finish(struct device *dev,
1477 struct subsys_interface *sif)
1479 unsigned int cpu = dev->id;
1481 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1484 pr_debug("%s: No cpu_data found\n", __func__);
1488 /* Only proceed for inactive policies */
1489 if (!policy_is_inactive(policy))
1492 /* If cpu is last user of policy, free policy */
1494 ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
1496 pr_err("%s: Failed to exit governor\n", __func__);
1502 * Perform the ->exit() even during light-weight tear-down,
1503 * since this is a core component, and is essential for the
1504 * subsequent light-weight ->init() to succeed.
1506 if (cpufreq_driver->exit)
1507 cpufreq_driver->exit(policy);
1509 /* Free the policy only if the driver is getting removed. */
1511 cpufreq_policy_free(policy, true);
1517 * cpufreq_remove_dev - remove a CPU device
1519 * Removes the cpufreq interface for a CPU device.
1521 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1523 unsigned int cpu = dev->id;
1527 * Only possible if 'cpu' is getting physically removed now. A hotplug
1528 * notifier should have already been called and we just need to remove
1529 * link or free policy here.
1531 if (cpu_is_offline(cpu)) {
1532 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1533 struct cpumask mask;
1538 cpumask_copy(&mask, policy->related_cpus);
1539 cpumask_clear_cpu(cpu, &mask);
1542 * Free policy only if all policy->related_cpus are removed
1545 if (cpumask_intersects(&mask, cpu_present_mask)) {
1546 remove_cpu_dev_symlink(policy, cpu);
1550 cpufreq_policy_free(policy, true);
1554 ret = __cpufreq_remove_dev_prepare(dev, sif);
1557 ret = __cpufreq_remove_dev_finish(dev, sif);
1562 static void handle_update(struct work_struct *work)
1564 struct cpufreq_policy *policy =
1565 container_of(work, struct cpufreq_policy, update);
1566 unsigned int cpu = policy->cpu;
1567 pr_debug("handle_update for cpu %u called\n", cpu);
1568 cpufreq_update_policy(cpu);
1572 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1574 * @policy: policy managing CPUs
1575 * @new_freq: CPU frequency the CPU actually runs at
1577 * We adjust to current frequency first, and need to clean up later.
1578 * So either call to cpufreq_update_policy() or schedule handle_update()).
1580 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1581 unsigned int new_freq)
1583 struct cpufreq_freqs freqs;
1585 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1586 policy->cur, new_freq);
1588 freqs.old = policy->cur;
1589 freqs.new = new_freq;
1591 cpufreq_freq_transition_begin(policy, &freqs);
1592 cpufreq_freq_transition_end(policy, &freqs, 0);
1596 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1599 * This is the last known freq, without actually getting it from the driver.
1600 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1602 unsigned int cpufreq_quick_get(unsigned int cpu)
1604 struct cpufreq_policy *policy;
1605 unsigned int ret_freq = 0;
1607 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1608 return cpufreq_driver->get(cpu);
1610 policy = cpufreq_cpu_get(cpu);
1612 ret_freq = policy->cur;
1613 cpufreq_cpu_put(policy);
1618 EXPORT_SYMBOL(cpufreq_quick_get);
1621 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1624 * Just return the max possible frequency for a given CPU.
1626 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1628 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1629 unsigned int ret_freq = 0;
1632 ret_freq = policy->max;
1633 cpufreq_cpu_put(policy);
1638 EXPORT_SYMBOL(cpufreq_quick_get_max);
1640 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1642 unsigned int ret_freq = 0;
1644 if (!cpufreq_driver->get)
1647 ret_freq = cpufreq_driver->get(policy->cpu);
1649 /* Updating inactive policies is invalid, so avoid doing that. */
1650 if (unlikely(policy_is_inactive(policy)))
1653 if (ret_freq && policy->cur &&
1654 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1655 /* verify no discrepancy between actual and
1656 saved value exists */
1657 if (unlikely(ret_freq != policy->cur)) {
1658 cpufreq_out_of_sync(policy, ret_freq);
1659 schedule_work(&policy->update);
1667 * cpufreq_get - get the current CPU frequency (in kHz)
1670 * Get the CPU current (static) CPU frequency
1672 unsigned int cpufreq_get(unsigned int cpu)
1674 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1675 unsigned int ret_freq = 0;
1678 down_read(&policy->rwsem);
1679 ret_freq = __cpufreq_get(policy);
1680 up_read(&policy->rwsem);
1682 cpufreq_cpu_put(policy);
1687 EXPORT_SYMBOL(cpufreq_get);
1689 static struct subsys_interface cpufreq_interface = {
1691 .subsys = &cpu_subsys,
1692 .add_dev = cpufreq_add_dev,
1693 .remove_dev = cpufreq_remove_dev,
1697 * In case platform wants some specific frequency to be configured
1700 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1704 if (!policy->suspend_freq) {
1705 pr_err("%s: suspend_freq can't be zero\n", __func__);
1709 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1710 policy->suspend_freq);
1712 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1713 CPUFREQ_RELATION_H);
1715 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1716 __func__, policy->suspend_freq, ret);
1720 EXPORT_SYMBOL(cpufreq_generic_suspend);
1723 * cpufreq_suspend() - Suspend CPUFreq governors
1725 * Called during system wide Suspend/Hibernate cycles for suspending governors
1726 * as some platforms can't change frequency after this point in suspend cycle.
1727 * Because some of the devices (like: i2c, regulators, etc) they use for
1728 * changing frequency are suspended quickly after this point.
1730 void cpufreq_suspend(void)
1732 struct cpufreq_policy *policy;
1734 if (!cpufreq_driver)
1740 pr_debug("%s: Suspending Governors\n", __func__);
1742 for_each_active_policy(policy) {
1743 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1744 pr_err("%s: Failed to stop governor for policy: %p\n",
1746 else if (cpufreq_driver->suspend
1747 && cpufreq_driver->suspend(policy))
1748 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1753 cpufreq_suspended = true;
1757 * cpufreq_resume() - Resume CPUFreq governors
1759 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1760 * are suspended with cpufreq_suspend().
1762 void cpufreq_resume(void)
1764 struct cpufreq_policy *policy;
1766 if (!cpufreq_driver)
1769 cpufreq_suspended = false;
1774 pr_debug("%s: Resuming Governors\n", __func__);
1776 for_each_active_policy(policy) {
1777 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1778 pr_err("%s: Failed to resume driver: %p\n", __func__,
1780 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1781 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1782 pr_err("%s: Failed to start governor for policy: %p\n",
1787 * schedule call cpufreq_update_policy() for first-online CPU, as that
1788 * wouldn't be hotplugged-out on suspend. It will verify that the
1789 * current freq is in sync with what we believe it to be.
1791 policy = cpufreq_cpu_get_raw(cpumask_first(cpu_online_mask));
1792 if (WARN_ON(!policy))
1795 schedule_work(&policy->update);
1799 * cpufreq_get_current_driver - return current driver's name
1801 * Return the name string of the currently loaded cpufreq driver
1804 const char *cpufreq_get_current_driver(void)
1807 return cpufreq_driver->name;
1811 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1814 * cpufreq_get_driver_data - return current driver data
1816 * Return the private data of the currently loaded cpufreq
1817 * driver, or NULL if no cpufreq driver is loaded.
1819 void *cpufreq_get_driver_data(void)
1822 return cpufreq_driver->driver_data;
1826 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1828 /*********************************************************************
1829 * NOTIFIER LISTS INTERFACE *
1830 *********************************************************************/
1833 * cpufreq_register_notifier - register a driver with cpufreq
1834 * @nb: notifier function to register
1835 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1837 * Add a driver to one of two lists: either a list of drivers that
1838 * are notified about clock rate changes (once before and once after
1839 * the transition), or a list of drivers that are notified about
1840 * changes in cpufreq policy.
1842 * This function may sleep, and has the same return conditions as
1843 * blocking_notifier_chain_register.
1845 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1849 if (cpufreq_disabled())
1852 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1855 case CPUFREQ_TRANSITION_NOTIFIER:
1856 ret = srcu_notifier_chain_register(
1857 &cpufreq_transition_notifier_list, nb);
1859 case CPUFREQ_POLICY_NOTIFIER:
1860 ret = blocking_notifier_chain_register(
1861 &cpufreq_policy_notifier_list, nb);
1869 EXPORT_SYMBOL(cpufreq_register_notifier);
1872 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1873 * @nb: notifier block to be unregistered
1874 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1876 * Remove a driver from the CPU frequency notifier list.
1878 * This function may sleep, and has the same return conditions as
1879 * blocking_notifier_chain_unregister.
1881 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1885 if (cpufreq_disabled())
1889 case CPUFREQ_TRANSITION_NOTIFIER:
1890 ret = srcu_notifier_chain_unregister(
1891 &cpufreq_transition_notifier_list, nb);
1893 case CPUFREQ_POLICY_NOTIFIER:
1894 ret = blocking_notifier_chain_unregister(
1895 &cpufreq_policy_notifier_list, nb);
1903 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1906 /*********************************************************************
1908 *********************************************************************/
1910 /* Must set freqs->new to intermediate frequency */
1911 static int __target_intermediate(struct cpufreq_policy *policy,
1912 struct cpufreq_freqs *freqs, int index)
1916 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1918 /* We don't need to switch to intermediate freq */
1922 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1923 __func__, policy->cpu, freqs->old, freqs->new);
1925 cpufreq_freq_transition_begin(policy, freqs);
1926 ret = cpufreq_driver->target_intermediate(policy, index);
1927 cpufreq_freq_transition_end(policy, freqs, ret);
1930 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1936 static int __target_index(struct cpufreq_policy *policy,
1937 struct cpufreq_frequency_table *freq_table, int index)
1939 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1940 unsigned int intermediate_freq = 0;
1941 int retval = -EINVAL;
1944 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1946 /* Handle switching to intermediate frequency */
1947 if (cpufreq_driver->get_intermediate) {
1948 retval = __target_intermediate(policy, &freqs, index);
1952 intermediate_freq = freqs.new;
1953 /* Set old freq to intermediate */
1954 if (intermediate_freq)
1955 freqs.old = freqs.new;
1958 freqs.new = freq_table[index].frequency;
1959 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1960 __func__, policy->cpu, freqs.old, freqs.new);
1962 cpufreq_freq_transition_begin(policy, &freqs);
1965 retval = cpufreq_driver->target_index(policy, index);
1967 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1971 cpufreq_freq_transition_end(policy, &freqs, retval);
1974 * Failed after setting to intermediate freq? Driver should have
1975 * reverted back to initial frequency and so should we. Check
1976 * here for intermediate_freq instead of get_intermediate, in
1977 * case we haven't switched to intermediate freq at all.
1979 if (unlikely(retval && intermediate_freq)) {
1980 freqs.old = intermediate_freq;
1981 freqs.new = policy->restore_freq;
1982 cpufreq_freq_transition_begin(policy, &freqs);
1983 cpufreq_freq_transition_end(policy, &freqs, 0);
1990 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1991 unsigned int target_freq,
1992 unsigned int relation)
1994 unsigned int old_target_freq = target_freq;
1995 int retval = -EINVAL;
1997 if (cpufreq_disabled())
2000 /* Make sure that target_freq is within supported range */
2001 if (target_freq > policy->max)
2002 target_freq = policy->max;
2003 if (target_freq < policy->min)
2004 target_freq = policy->min;
2006 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2007 policy->cpu, target_freq, relation, old_target_freq);
2010 * This might look like a redundant call as we are checking it again
2011 * after finding index. But it is left intentionally for cases where
2012 * exactly same freq is called again and so we can save on few function
2015 if (target_freq == policy->cur)
2018 /* Save last value to restore later on errors */
2019 policy->restore_freq = policy->cur;
2021 if (cpufreq_driver->target)
2022 retval = cpufreq_driver->target(policy, target_freq, relation);
2023 else if (cpufreq_driver->target_index) {
2024 struct cpufreq_frequency_table *freq_table;
2027 freq_table = cpufreq_frequency_get_table(policy->cpu);
2028 if (unlikely(!freq_table)) {
2029 pr_err("%s: Unable to find freq_table\n", __func__);
2033 retval = cpufreq_frequency_table_target(policy, freq_table,
2034 target_freq, relation, &index);
2035 if (unlikely(retval)) {
2036 pr_err("%s: Unable to find matching freq\n", __func__);
2040 if (freq_table[index].frequency == policy->cur) {
2045 retval = __target_index(policy, freq_table, index);
2051 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2053 int cpufreq_driver_target(struct cpufreq_policy *policy,
2054 unsigned int target_freq,
2055 unsigned int relation)
2059 down_write(&policy->rwsem);
2061 ret = __cpufreq_driver_target(policy, target_freq, relation);
2063 up_write(&policy->rwsem);
2067 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2069 static int __cpufreq_governor(struct cpufreq_policy *policy,
2074 /* Only must be defined when default governor is known to have latency
2075 restrictions, like e.g. conservative or ondemand.
2076 That this is the case is already ensured in Kconfig
2078 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
2079 struct cpufreq_governor *gov = &cpufreq_gov_performance;
2081 struct cpufreq_governor *gov = NULL;
2084 /* Don't start any governor operations if we are entering suspend */
2085 if (cpufreq_suspended)
2088 * Governor might not be initiated here if ACPI _PPC changed
2089 * notification happened, so check it.
2091 if (!policy->governor)
2094 if (policy->governor->max_transition_latency &&
2095 policy->cpuinfo.transition_latency >
2096 policy->governor->max_transition_latency) {
2100 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2101 policy->governor->name, gov->name);
2102 policy->governor = gov;
2106 if (event == CPUFREQ_GOV_POLICY_INIT)
2107 if (!try_module_get(policy->governor->owner))
2110 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2111 policy->cpu, event);
2113 mutex_lock(&cpufreq_governor_lock);
2114 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2115 || (!policy->governor_enabled
2116 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2117 mutex_unlock(&cpufreq_governor_lock);
2121 if (event == CPUFREQ_GOV_STOP)
2122 policy->governor_enabled = false;
2123 else if (event == CPUFREQ_GOV_START)
2124 policy->governor_enabled = true;
2126 mutex_unlock(&cpufreq_governor_lock);
2128 ret = policy->governor->governor(policy, event);
2131 if (event == CPUFREQ_GOV_POLICY_INIT)
2132 policy->governor->initialized++;
2133 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2134 policy->governor->initialized--;
2136 /* Restore original values */
2137 mutex_lock(&cpufreq_governor_lock);
2138 if (event == CPUFREQ_GOV_STOP)
2139 policy->governor_enabled = true;
2140 else if (event == CPUFREQ_GOV_START)
2141 policy->governor_enabled = false;
2142 mutex_unlock(&cpufreq_governor_lock);
2145 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2146 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2147 module_put(policy->governor->owner);
2152 int cpufreq_register_governor(struct cpufreq_governor *governor)
2159 if (cpufreq_disabled())
2162 mutex_lock(&cpufreq_governor_mutex);
2164 governor->initialized = 0;
2166 if (!find_governor(governor->name)) {
2168 list_add(&governor->governor_list, &cpufreq_governor_list);
2171 mutex_unlock(&cpufreq_governor_mutex);
2174 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2176 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2178 struct cpufreq_policy *policy;
2179 unsigned long flags;
2184 if (cpufreq_disabled())
2187 /* clear last_governor for all inactive policies */
2188 read_lock_irqsave(&cpufreq_driver_lock, flags);
2189 for_each_inactive_policy(policy) {
2190 if (!strcmp(policy->last_governor, governor->name)) {
2191 policy->governor = NULL;
2192 strcpy(policy->last_governor, "\0");
2195 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2197 mutex_lock(&cpufreq_governor_mutex);
2198 list_del(&governor->governor_list);
2199 mutex_unlock(&cpufreq_governor_mutex);
2202 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2205 /*********************************************************************
2206 * POLICY INTERFACE *
2207 *********************************************************************/
2210 * cpufreq_get_policy - get the current cpufreq_policy
2211 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2214 * Reads the current cpufreq policy.
2216 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2218 struct cpufreq_policy *cpu_policy;
2222 cpu_policy = cpufreq_cpu_get(cpu);
2226 memcpy(policy, cpu_policy, sizeof(*policy));
2228 cpufreq_cpu_put(cpu_policy);
2231 EXPORT_SYMBOL(cpufreq_get_policy);
2234 * policy : current policy.
2235 * new_policy: policy to be set.
2237 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2238 struct cpufreq_policy *new_policy)
2240 struct cpufreq_governor *old_gov;
2243 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2244 new_policy->cpu, new_policy->min, new_policy->max);
2246 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2248 if (new_policy->min > policy->max || new_policy->max < policy->min)
2251 /* verify the cpu speed can be set within this limit */
2252 ret = cpufreq_driver->verify(new_policy);
2256 /* adjust if necessary - all reasons */
2257 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2258 CPUFREQ_ADJUST, new_policy);
2260 /* adjust if necessary - hardware incompatibility*/
2261 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2262 CPUFREQ_INCOMPATIBLE, new_policy);
2265 * verify the cpu speed can be set within this limit, which might be
2266 * different to the first one
2268 ret = cpufreq_driver->verify(new_policy);
2272 /* notification of the new policy */
2273 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2274 CPUFREQ_NOTIFY, new_policy);
2276 policy->min = new_policy->min;
2277 policy->max = new_policy->max;
2279 pr_debug("new min and max freqs are %u - %u kHz\n",
2280 policy->min, policy->max);
2282 if (cpufreq_driver->setpolicy) {
2283 policy->policy = new_policy->policy;
2284 pr_debug("setting range\n");
2285 return cpufreq_driver->setpolicy(new_policy);
2288 if (new_policy->governor == policy->governor)
2291 pr_debug("governor switch\n");
2293 /* save old, working values */
2294 old_gov = policy->governor;
2295 /* end old governor */
2297 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2298 up_write(&policy->rwsem);
2299 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2300 down_write(&policy->rwsem);
2303 /* start new governor */
2304 policy->governor = new_policy->governor;
2305 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2306 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2309 up_write(&policy->rwsem);
2310 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2311 down_write(&policy->rwsem);
2314 /* new governor failed, so re-start old one */
2315 pr_debug("starting governor %s failed\n", policy->governor->name);
2317 policy->governor = old_gov;
2318 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2319 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2325 pr_debug("governor: change or update limits\n");
2326 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2330 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2331 * @cpu: CPU which shall be re-evaluated
2333 * Useful for policy notifiers which have different necessities
2334 * at different times.
2336 int cpufreq_update_policy(unsigned int cpu)
2338 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2339 struct cpufreq_policy new_policy;
2345 down_write(&policy->rwsem);
2347 pr_debug("updating policy for CPU %u\n", cpu);
2348 memcpy(&new_policy, policy, sizeof(*policy));
2349 new_policy.min = policy->user_policy.min;
2350 new_policy.max = policy->user_policy.max;
2351 new_policy.policy = policy->user_policy.policy;
2352 new_policy.governor = policy->user_policy.governor;
2355 * BIOS might change freq behind our back
2356 * -> ask driver for current freq and notify governors about a change
2358 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2359 new_policy.cur = cpufreq_driver->get(cpu);
2360 if (WARN_ON(!new_policy.cur)) {
2366 pr_debug("Driver did not initialize current freq\n");
2367 policy->cur = new_policy.cur;
2369 if (policy->cur != new_policy.cur && has_target())
2370 cpufreq_out_of_sync(policy, new_policy.cur);
2374 ret = cpufreq_set_policy(policy, &new_policy);
2377 up_write(&policy->rwsem);
2379 cpufreq_cpu_put(policy);
2382 EXPORT_SYMBOL(cpufreq_update_policy);
2384 static int cpufreq_cpu_callback(struct notifier_block *nfb,
2385 unsigned long action, void *hcpu)
2387 unsigned int cpu = (unsigned long)hcpu;
2390 dev = get_cpu_device(cpu);
2392 switch (action & ~CPU_TASKS_FROZEN) {
2394 cpufreq_add_dev(dev, NULL);
2397 case CPU_DOWN_PREPARE:
2398 __cpufreq_remove_dev_prepare(dev, NULL);
2402 __cpufreq_remove_dev_finish(dev, NULL);
2405 case CPU_DOWN_FAILED:
2406 cpufreq_add_dev(dev, NULL);
2413 static struct notifier_block __refdata cpufreq_cpu_notifier = {
2414 .notifier_call = cpufreq_cpu_callback,
2417 /*********************************************************************
2419 *********************************************************************/
2420 static int cpufreq_boost_set_sw(int state)
2422 struct cpufreq_frequency_table *freq_table;
2423 struct cpufreq_policy *policy;
2426 for_each_active_policy(policy) {
2427 freq_table = cpufreq_frequency_get_table(policy->cpu);
2429 ret = cpufreq_frequency_table_cpuinfo(policy,
2432 pr_err("%s: Policy frequency update failed\n",
2436 policy->user_policy.max = policy->max;
2437 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2444 int cpufreq_boost_trigger_state(int state)
2446 unsigned long flags;
2449 if (cpufreq_driver->boost_enabled == state)
2452 write_lock_irqsave(&cpufreq_driver_lock, flags);
2453 cpufreq_driver->boost_enabled = state;
2454 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2456 ret = cpufreq_driver->set_boost(state);
2458 write_lock_irqsave(&cpufreq_driver_lock, flags);
2459 cpufreq_driver->boost_enabled = !state;
2460 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2462 pr_err("%s: Cannot %s BOOST\n",
2463 __func__, state ? "enable" : "disable");
2469 int cpufreq_boost_supported(void)
2471 if (likely(cpufreq_driver))
2472 return cpufreq_driver->boost_supported;
2476 EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2478 int cpufreq_boost_enabled(void)
2480 return cpufreq_driver->boost_enabled;
2482 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2484 /*********************************************************************
2485 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2486 *********************************************************************/
2489 * cpufreq_register_driver - register a CPU Frequency driver
2490 * @driver_data: A struct cpufreq_driver containing the values#
2491 * submitted by the CPU Frequency driver.
2493 * Registers a CPU Frequency driver to this core code. This code
2494 * returns zero on success, -EBUSY when another driver got here first
2495 * (and isn't unregistered in the meantime).
2498 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2500 unsigned long flags;
2503 if (cpufreq_disabled())
2506 if (!driver_data || !driver_data->verify || !driver_data->init ||
2507 !(driver_data->setpolicy || driver_data->target_index ||
2508 driver_data->target) ||
2509 (driver_data->setpolicy && (driver_data->target_index ||
2510 driver_data->target)) ||
2511 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2514 pr_debug("trying to register driver %s\n", driver_data->name);
2516 write_lock_irqsave(&cpufreq_driver_lock, flags);
2517 if (cpufreq_driver) {
2518 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2521 cpufreq_driver = driver_data;
2522 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2524 if (driver_data->setpolicy)
2525 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2527 if (cpufreq_boost_supported()) {
2529 * Check if driver provides function to enable boost -
2530 * if not, use cpufreq_boost_set_sw as default
2532 if (!cpufreq_driver->set_boost)
2533 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2535 ret = cpufreq_sysfs_create_file(&boost.attr);
2537 pr_err("%s: cannot register global BOOST sysfs file\n",
2539 goto err_null_driver;
2543 ret = subsys_interface_register(&cpufreq_interface);
2545 goto err_boost_unreg;
2547 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2548 list_empty(&cpufreq_policy_list)) {
2549 /* if all ->init() calls failed, unregister */
2550 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2555 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2556 pr_debug("driver %s up and running\n", driver_data->name);
2560 subsys_interface_unregister(&cpufreq_interface);
2562 if (cpufreq_boost_supported())
2563 cpufreq_sysfs_remove_file(&boost.attr);
2565 write_lock_irqsave(&cpufreq_driver_lock, flags);
2566 cpufreq_driver = NULL;
2567 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2570 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2573 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2575 * Unregister the current CPUFreq driver. Only call this if you have
2576 * the right to do so, i.e. if you have succeeded in initialising before!
2577 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2578 * currently not initialised.
2580 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2582 unsigned long flags;
2584 if (!cpufreq_driver || (driver != cpufreq_driver))
2587 pr_debug("unregistering driver %s\n", driver->name);
2589 subsys_interface_unregister(&cpufreq_interface);
2590 if (cpufreq_boost_supported())
2591 cpufreq_sysfs_remove_file(&boost.attr);
2593 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2595 down_write(&cpufreq_rwsem);
2596 write_lock_irqsave(&cpufreq_driver_lock, flags);
2598 cpufreq_driver = NULL;
2600 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2601 up_write(&cpufreq_rwsem);
2605 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2608 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2609 * or mutexes when secondary CPUs are halted.
2611 static struct syscore_ops cpufreq_syscore_ops = {
2612 .shutdown = cpufreq_suspend,
2615 static int __init cpufreq_core_init(void)
2617 if (cpufreq_disabled())
2620 cpufreq_global_kobject = kobject_create();
2621 BUG_ON(!cpufreq_global_kobject);
2623 register_syscore_ops(&cpufreq_syscore_ops);
2627 core_initcall(cpufreq_core_init);