2 * linux/drivers/cpufreq/cpufreq.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10 * Fix handling for CPU hotplug -- affected CPUs
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/notifier.h>
22 #include <linux/cpufreq.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/device.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
32 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
36 * The "cpufreq driver" - the arch- or hardware-dependent low
37 * level driver of CPUFreq support, and its spinlock. This lock
38 * also protects the cpufreq_cpu_data array.
40 static struct cpufreq_driver *cpufreq_driver;
41 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
46 static DEFINE_SPINLOCK(cpufreq_driver_lock);
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
52 * The rules for this semaphore:
53 * - Any routine that wants to read from the policy structure will
54 * do a down_read on this semaphore.
55 * - Any routine that will write to the policy structure and/or may take away
56 * the policy altogether (eg. CPU hotplug), will hold this lock in write
57 * mode before doing so.
60 * - All holders of the lock should check to make sure that the CPU they
61 * are concerned with are online after they get the lock.
62 * - Governor routines that can be called in cpufreq hotplug path should not
63 * take this sem as top level hotplug notifier handler takes this.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
67 static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
68 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
70 #define lock_policy_rwsem(mode, cpu) \
71 int lock_policy_rwsem_##mode \
74 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
75 BUG_ON(policy_cpu == -1); \
76 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
77 if (unlikely(!cpu_online(cpu))) { \
78 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
85 lock_policy_rwsem(read, cpu);
86 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read);
88 lock_policy_rwsem(write, cpu);
89 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write);
91 void unlock_policy_rwsem_read(int cpu)
93 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
94 BUG_ON(policy_cpu == -1);
95 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
97 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read);
99 void unlock_policy_rwsem_write(int cpu)
101 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
102 BUG_ON(policy_cpu == -1);
103 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
105 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write);
108 /* internal prototypes */
109 static int __cpufreq_governor(struct cpufreq_policy *policy,
111 static unsigned int __cpufreq_get(unsigned int cpu);
112 static void handle_update(struct work_struct *work);
115 * Two notifier lists: the "policy" list is involved in the
116 * validation process for a new CPU frequency policy; the
117 * "transition" list for kernel code that needs to handle
118 * changes to devices when the CPU clock speed changes.
119 * The mutex locks both lists.
121 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
122 static struct srcu_notifier_head cpufreq_transition_notifier_list;
124 static bool init_cpufreq_transition_notifier_list_called;
125 static int __init init_cpufreq_transition_notifier_list(void)
127 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
128 init_cpufreq_transition_notifier_list_called = true;
131 pure_initcall(init_cpufreq_transition_notifier_list);
133 static LIST_HEAD(cpufreq_governor_list);
134 static DEFINE_MUTEX(cpufreq_governor_mutex);
136 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
138 struct cpufreq_policy *data;
141 if (cpu >= nr_cpu_ids)
144 /* get the cpufreq driver */
145 spin_lock_irqsave(&cpufreq_driver_lock, flags);
150 if (!try_module_get(cpufreq_driver->owner))
155 data = per_cpu(cpufreq_cpu_data, cpu);
158 goto err_out_put_module;
160 if (!kobject_get(&data->kobj))
161 goto err_out_put_module;
163 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
167 module_put(cpufreq_driver->owner);
169 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
173 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
176 void cpufreq_cpu_put(struct cpufreq_policy *data)
178 kobject_put(&data->kobj);
179 module_put(cpufreq_driver->owner);
181 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
184 /*********************************************************************
185 * UNIFIED DEBUG HELPERS *
186 *********************************************************************/
187 #ifdef CONFIG_CPU_FREQ_DEBUG
189 /* what part(s) of the CPUfreq subsystem are debugged? */
190 static unsigned int debug;
192 /* is the debug output ratelimit'ed using printk_ratelimit? User can
193 * set or modify this value.
195 static unsigned int debug_ratelimit = 1;
197 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
198 * loading of a cpufreq driver, temporarily disabled when a new policy
199 * is set, and disabled upon cpufreq driver removal
201 static unsigned int disable_ratelimit = 1;
202 static DEFINE_SPINLOCK(disable_ratelimit_lock);
204 static void cpufreq_debug_enable_ratelimit(void)
208 spin_lock_irqsave(&disable_ratelimit_lock, flags);
209 if (disable_ratelimit)
211 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
214 static void cpufreq_debug_disable_ratelimit(void)
218 spin_lock_irqsave(&disable_ratelimit_lock, flags);
220 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
223 void cpufreq_debug_printk(unsigned int type, const char *prefix,
224 const char *fmt, ...)
233 spin_lock_irqsave(&disable_ratelimit_lock, flags);
234 if (!disable_ratelimit && debug_ratelimit
235 && !printk_ratelimit()) {
236 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
239 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
241 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
244 len += vsnprintf(&s[len], (256 - len), fmt, args);
252 EXPORT_SYMBOL(cpufreq_debug_printk);
255 module_param(debug, uint, 0644);
256 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
257 " 2 to debug drivers, and 4 to debug governors.");
259 module_param(debug_ratelimit, uint, 0644);
260 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
261 " set to 0 to disable ratelimiting.");
263 #else /* !CONFIG_CPU_FREQ_DEBUG */
265 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
266 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
268 #endif /* CONFIG_CPU_FREQ_DEBUG */
271 /*********************************************************************
272 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
273 *********************************************************************/
276 * adjust_jiffies - adjust the system "loops_per_jiffy"
278 * This function alters the system "loops_per_jiffy" for the clock
279 * speed change. Note that loops_per_jiffy cannot be updated on SMP
280 * systems as each CPU might be scaled differently. So, use the arch
281 * per-CPU loops_per_jiffy value wherever possible.
284 static unsigned long l_p_j_ref;
285 static unsigned int l_p_j_ref_freq;
287 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
289 if (ci->flags & CPUFREQ_CONST_LOOPS)
292 if (!l_p_j_ref_freq) {
293 l_p_j_ref = loops_per_jiffy;
294 l_p_j_ref_freq = ci->old;
295 dprintk("saving %lu as reference value for loops_per_jiffy; "
296 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
298 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
299 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
300 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
301 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
303 dprintk("scaling loops_per_jiffy to %lu "
304 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
308 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
316 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
317 * on frequency transition.
319 * This function calls the transition notifiers and the "adjust_jiffies"
320 * function. It is called twice on all CPU frequency changes that have
323 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
325 struct cpufreq_policy *policy;
327 BUG_ON(irqs_disabled());
329 freqs->flags = cpufreq_driver->flags;
330 dprintk("notification %u of frequency transition to %u kHz\n",
333 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
336 case CPUFREQ_PRECHANGE:
337 /* detect if the driver reported a value as "old frequency"
338 * which is not equal to what the cpufreq core thinks is
341 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
342 if ((policy) && (policy->cpu == freqs->cpu) &&
343 (policy->cur) && (policy->cur != freqs->old)) {
344 dprintk("Warning: CPU frequency is"
345 " %u, cpufreq assumed %u kHz.\n",
346 freqs->old, policy->cur);
347 freqs->old = policy->cur;
350 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
351 CPUFREQ_PRECHANGE, freqs);
352 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
355 case CPUFREQ_POSTCHANGE:
356 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
357 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
358 CPUFREQ_POSTCHANGE, freqs);
359 if (likely(policy) && likely(policy->cpu == freqs->cpu))
360 policy->cur = freqs->new;
364 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
368 /*********************************************************************
370 *********************************************************************/
372 static struct cpufreq_governor *__find_governor(const char *str_governor)
374 struct cpufreq_governor *t;
376 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
377 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
384 * cpufreq_parse_governor - parse a governor string
386 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
387 struct cpufreq_governor **governor)
394 if (cpufreq_driver->setpolicy) {
395 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
396 *policy = CPUFREQ_POLICY_PERFORMANCE;
398 } else if (!strnicmp(str_governor, "powersave",
400 *policy = CPUFREQ_POLICY_POWERSAVE;
403 } else if (cpufreq_driver->target) {
404 struct cpufreq_governor *t;
406 mutex_lock(&cpufreq_governor_mutex);
408 t = __find_governor(str_governor);
411 char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
417 mutex_unlock(&cpufreq_governor_mutex);
418 ret = request_module("%s", name);
419 mutex_lock(&cpufreq_governor_mutex);
422 t = __find_governor(str_governor);
433 mutex_unlock(&cpufreq_governor_mutex);
441 * cpufreq_per_cpu_attr_read() / show_##file_name() -
442 * print out cpufreq information
444 * Write out information from cpufreq_driver->policy[cpu]; object must be
448 #define show_one(file_name, object) \
449 static ssize_t show_##file_name \
450 (struct cpufreq_policy *policy, char *buf) \
452 return sprintf(buf, "%u\n", policy->object); \
455 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
456 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
457 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
458 show_one(scaling_min_freq, min);
459 show_one(scaling_max_freq, max);
460 show_one(scaling_cur_freq, cur);
462 static int __cpufreq_set_policy(struct cpufreq_policy *data,
463 struct cpufreq_policy *policy);
466 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
468 #define store_one(file_name, object) \
469 static ssize_t store_##file_name \
470 (struct cpufreq_policy *policy, const char *buf, size_t count) \
472 unsigned int ret = -EINVAL; \
473 struct cpufreq_policy new_policy; \
475 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
479 ret = sscanf(buf, "%u", &new_policy.object); \
483 ret = __cpufreq_set_policy(policy, &new_policy); \
484 policy->user_policy.object = policy->object; \
486 return ret ? ret : count; \
489 store_one(scaling_min_freq, min);
490 store_one(scaling_max_freq, max);
493 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
495 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
498 unsigned int cur_freq = __cpufreq_get(policy->cpu);
500 return sprintf(buf, "<unknown>");
501 return sprintf(buf, "%u\n", cur_freq);
506 * show_scaling_governor - show the current policy for the specified CPU
508 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
510 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
511 return sprintf(buf, "powersave\n");
512 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
513 return sprintf(buf, "performance\n");
514 else if (policy->governor)
515 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
516 policy->governor->name);
522 * store_scaling_governor - store policy for the specified CPU
524 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
525 const char *buf, size_t count)
527 unsigned int ret = -EINVAL;
528 char str_governor[16];
529 struct cpufreq_policy new_policy;
531 ret = cpufreq_get_policy(&new_policy, policy->cpu);
535 ret = sscanf(buf, "%15s", str_governor);
539 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
540 &new_policy.governor))
543 /* Do not use cpufreq_set_policy here or the user_policy.max
544 will be wrongly overridden */
545 ret = __cpufreq_set_policy(policy, &new_policy);
547 policy->user_policy.policy = policy->policy;
548 policy->user_policy.governor = policy->governor;
557 * show_scaling_driver - show the cpufreq driver currently loaded
559 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
561 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
565 * show_scaling_available_governors - show the available CPUfreq governors
567 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
571 struct cpufreq_governor *t;
573 if (!cpufreq_driver->target) {
574 i += sprintf(buf, "performance powersave");
578 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
579 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
580 - (CPUFREQ_NAME_LEN + 2)))
582 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
585 i += sprintf(&buf[i], "\n");
589 static ssize_t show_cpus(const struct cpumask *mask, char *buf)
594 for_each_cpu(cpu, mask) {
596 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
597 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
598 if (i >= (PAGE_SIZE - 5))
601 i += sprintf(&buf[i], "\n");
606 * show_related_cpus - show the CPUs affected by each transition even if
607 * hw coordination is in use
609 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
611 if (cpumask_empty(policy->related_cpus))
612 return show_cpus(policy->cpus, buf);
613 return show_cpus(policy->related_cpus, buf);
617 * show_affected_cpus - show the CPUs affected by each transition
619 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
621 return show_cpus(policy->cpus, buf);
624 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
625 const char *buf, size_t count)
627 unsigned int freq = 0;
630 if (!policy->governor || !policy->governor->store_setspeed)
633 ret = sscanf(buf, "%u", &freq);
637 policy->governor->store_setspeed(policy, freq);
642 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
644 if (!policy->governor || !policy->governor->show_setspeed)
645 return sprintf(buf, "<unsupported>\n");
647 return policy->governor->show_setspeed(policy, buf);
651 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
653 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
657 if (cpufreq_driver->bios_limit) {
658 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
660 return sprintf(buf, "%u\n", limit);
662 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
665 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
666 cpufreq_freq_attr_ro(cpuinfo_min_freq);
667 cpufreq_freq_attr_ro(cpuinfo_max_freq);
668 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
669 cpufreq_freq_attr_ro(scaling_available_governors);
670 cpufreq_freq_attr_ro(scaling_driver);
671 cpufreq_freq_attr_ro(scaling_cur_freq);
672 cpufreq_freq_attr_ro(bios_limit);
673 cpufreq_freq_attr_ro(related_cpus);
674 cpufreq_freq_attr_ro(affected_cpus);
675 cpufreq_freq_attr_rw(scaling_min_freq);
676 cpufreq_freq_attr_rw(scaling_max_freq);
677 cpufreq_freq_attr_rw(scaling_governor);
678 cpufreq_freq_attr_rw(scaling_setspeed);
680 static struct attribute *default_attrs[] = {
681 &cpuinfo_min_freq.attr,
682 &cpuinfo_max_freq.attr,
683 &cpuinfo_transition_latency.attr,
684 &scaling_min_freq.attr,
685 &scaling_max_freq.attr,
688 &scaling_governor.attr,
689 &scaling_driver.attr,
690 &scaling_available_governors.attr,
691 &scaling_setspeed.attr,
695 struct kobject *cpufreq_global_kobject;
696 EXPORT_SYMBOL(cpufreq_global_kobject);
698 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
699 #define to_attr(a) container_of(a, struct freq_attr, attr)
701 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
703 struct cpufreq_policy *policy = to_policy(kobj);
704 struct freq_attr *fattr = to_attr(attr);
705 ssize_t ret = -EINVAL;
706 policy = cpufreq_cpu_get(policy->cpu);
710 if (lock_policy_rwsem_read(policy->cpu) < 0)
714 ret = fattr->show(policy, buf);
718 unlock_policy_rwsem_read(policy->cpu);
720 cpufreq_cpu_put(policy);
725 static ssize_t store(struct kobject *kobj, struct attribute *attr,
726 const char *buf, size_t count)
728 struct cpufreq_policy *policy = to_policy(kobj);
729 struct freq_attr *fattr = to_attr(attr);
730 ssize_t ret = -EINVAL;
731 policy = cpufreq_cpu_get(policy->cpu);
735 if (lock_policy_rwsem_write(policy->cpu) < 0)
739 ret = fattr->store(policy, buf, count);
743 unlock_policy_rwsem_write(policy->cpu);
745 cpufreq_cpu_put(policy);
750 static void cpufreq_sysfs_release(struct kobject *kobj)
752 struct cpufreq_policy *policy = to_policy(kobj);
753 dprintk("last reference is dropped\n");
754 complete(&policy->kobj_unregister);
757 static const struct sysfs_ops sysfs_ops = {
762 static struct kobj_type ktype_cpufreq = {
763 .sysfs_ops = &sysfs_ops,
764 .default_attrs = default_attrs,
765 .release = cpufreq_sysfs_release,
772 * Positive: When we have a managed CPU and the sysfs got symlinked
774 static int cpufreq_add_dev_policy(unsigned int cpu,
775 struct cpufreq_policy *policy,
776 struct sys_device *sys_dev)
782 #ifdef CONFIG_HOTPLUG_CPU
783 struct cpufreq_governor *gov;
785 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
787 policy->governor = gov;
788 dprintk("Restoring governor %s for cpu %d\n",
789 policy->governor->name, cpu);
793 for_each_cpu(j, policy->cpus) {
794 struct cpufreq_policy *managed_policy;
799 /* Check for existing affected CPUs.
800 * They may not be aware of it due to CPU Hotplug.
801 * cpufreq_cpu_put is called when the device is removed
802 * in __cpufreq_remove_dev()
804 managed_policy = cpufreq_cpu_get(j);
805 if (unlikely(managed_policy)) {
807 /* Set proper policy_cpu */
808 unlock_policy_rwsem_write(cpu);
809 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
811 if (lock_policy_rwsem_write(cpu) < 0) {
812 /* Should not go through policy unlock path */
813 if (cpufreq_driver->exit)
814 cpufreq_driver->exit(policy);
815 cpufreq_cpu_put(managed_policy);
819 spin_lock_irqsave(&cpufreq_driver_lock, flags);
820 cpumask_copy(managed_policy->cpus, policy->cpus);
821 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
822 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
824 dprintk("CPU already managed, adding link\n");
825 ret = sysfs_create_link(&sys_dev->kobj,
826 &managed_policy->kobj,
829 cpufreq_cpu_put(managed_policy);
831 * Success. We only needed to be added to the mask.
832 * Call driver->exit() because only the cpu parent of
833 * the kobj needed to call init().
835 if (cpufreq_driver->exit)
836 cpufreq_driver->exit(policy);
849 /* symlink affected CPUs */
850 static int cpufreq_add_dev_symlink(unsigned int cpu,
851 struct cpufreq_policy *policy)
856 for_each_cpu(j, policy->cpus) {
857 struct cpufreq_policy *managed_policy;
858 struct sys_device *cpu_sys_dev;
865 dprintk("CPU %u already managed, adding link\n", j);
866 managed_policy = cpufreq_cpu_get(cpu);
867 cpu_sys_dev = get_cpu_sysdev(j);
868 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
871 cpufreq_cpu_put(managed_policy);
878 static int cpufreq_add_dev_interface(unsigned int cpu,
879 struct cpufreq_policy *policy,
880 struct sys_device *sys_dev)
882 struct cpufreq_policy new_policy;
883 struct freq_attr **drv_attr;
888 /* prepare interface data */
889 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
890 &sys_dev->kobj, "cpufreq");
894 /* set up files for this cpu device */
895 drv_attr = cpufreq_driver->attr;
896 while ((drv_attr) && (*drv_attr)) {
897 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
899 goto err_out_kobj_put;
902 if (cpufreq_driver->get) {
903 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
905 goto err_out_kobj_put;
907 if (cpufreq_driver->target) {
908 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
910 goto err_out_kobj_put;
912 if (cpufreq_driver->bios_limit) {
913 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
915 goto err_out_kobj_put;
918 spin_lock_irqsave(&cpufreq_driver_lock, flags);
919 for_each_cpu(j, policy->cpus) {
922 per_cpu(cpufreq_cpu_data, j) = policy;
923 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
925 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
927 ret = cpufreq_add_dev_symlink(cpu, policy);
929 goto err_out_kobj_put;
931 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
932 /* assure that the starting sequence is run in __cpufreq_set_policy */
933 policy->governor = NULL;
935 /* set default policy */
936 ret = __cpufreq_set_policy(policy, &new_policy);
937 policy->user_policy.policy = policy->policy;
938 policy->user_policy.governor = policy->governor;
941 dprintk("setting policy failed\n");
942 if (cpufreq_driver->exit)
943 cpufreq_driver->exit(policy);
948 kobject_put(&policy->kobj);
949 wait_for_completion(&policy->kobj_unregister);
955 * cpufreq_add_dev - add a CPU device
957 * Adds the cpufreq interface for a CPU device.
959 * The Oracle says: try running cpufreq registration/unregistration concurrently
960 * with with cpu hotplugging and all hell will break loose. Tried to clean this
961 * mess up, but more thorough testing is needed. - Mathieu
963 static int cpufreq_add_dev(struct sys_device *sys_dev)
965 unsigned int cpu = sys_dev->id;
966 int ret = 0, found = 0;
967 struct cpufreq_policy *policy;
970 #ifdef CONFIG_HOTPLUG_CPU
974 if (cpu_is_offline(cpu))
977 cpufreq_debug_disable_ratelimit();
978 dprintk("adding CPU %u\n", cpu);
981 /* check whether a different CPU already registered this
982 * CPU because it is in the same boat. */
983 policy = cpufreq_cpu_get(cpu);
984 if (unlikely(policy)) {
985 cpufreq_cpu_put(policy);
986 cpufreq_debug_enable_ratelimit();
991 if (!try_module_get(cpufreq_driver->owner)) {
997 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
1001 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1002 goto err_free_policy;
1004 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1005 goto err_free_cpumask;
1008 cpumask_copy(policy->cpus, cpumask_of(cpu));
1010 /* Initially set CPU itself as the policy_cpu */
1011 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
1012 ret = (lock_policy_rwsem_write(cpu) < 0);
1015 init_completion(&policy->kobj_unregister);
1016 INIT_WORK(&policy->update, handle_update);
1018 /* Set governor before ->init, so that driver could check it */
1019 #ifdef CONFIG_HOTPLUG_CPU
1020 for_each_online_cpu(sibling) {
1021 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
1022 if (cp && cp->governor &&
1023 (cpumask_test_cpu(cpu, cp->related_cpus))) {
1024 policy->governor = cp->governor;
1031 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
1032 /* call driver. From then on the cpufreq must be able
1033 * to accept all calls to ->verify and ->setpolicy for this CPU
1035 ret = cpufreq_driver->init(policy);
1037 dprintk("initialization failed\n");
1038 goto err_unlock_policy;
1040 policy->user_policy.min = policy->min;
1041 policy->user_policy.max = policy->max;
1043 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1044 CPUFREQ_START, policy);
1046 ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
1049 /* This is a managed cpu, symlink created,
1052 goto err_unlock_policy;
1055 ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
1057 goto err_out_unregister;
1059 unlock_policy_rwsem_write(cpu);
1061 kobject_uevent(&policy->kobj, KOBJ_ADD);
1062 module_put(cpufreq_driver->owner);
1063 dprintk("initialization complete\n");
1064 cpufreq_debug_enable_ratelimit();
1070 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1071 for_each_cpu(j, policy->cpus)
1072 per_cpu(cpufreq_cpu_data, j) = NULL;
1073 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1075 kobject_put(&policy->kobj);
1076 wait_for_completion(&policy->kobj_unregister);
1079 unlock_policy_rwsem_write(cpu);
1080 free_cpumask_var(policy->related_cpus);
1082 free_cpumask_var(policy->cpus);
1086 module_put(cpufreq_driver->owner);
1088 cpufreq_debug_enable_ratelimit();
1094 * __cpufreq_remove_dev - remove a CPU device
1096 * Removes the cpufreq interface for a CPU device.
1097 * Caller should already have policy_rwsem in write mode for this CPU.
1098 * This routine frees the rwsem before returning.
1100 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1102 unsigned int cpu = sys_dev->id;
1103 unsigned long flags;
1104 struct cpufreq_policy *data;
1105 struct kobject *kobj;
1106 struct completion *cmp;
1108 struct sys_device *cpu_sys_dev;
1112 cpufreq_debug_disable_ratelimit();
1113 dprintk("unregistering CPU %u\n", cpu);
1115 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1116 data = per_cpu(cpufreq_cpu_data, cpu);
1119 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1120 cpufreq_debug_enable_ratelimit();
1121 unlock_policy_rwsem_write(cpu);
1124 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1128 /* if this isn't the CPU which is the parent of the kobj, we
1129 * only need to unlink, put and exit
1131 if (unlikely(cpu != data->cpu)) {
1132 dprintk("removing link\n");
1133 cpumask_clear_cpu(cpu, data->cpus);
1134 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1135 kobj = &sys_dev->kobj;
1136 cpufreq_cpu_put(data);
1137 cpufreq_debug_enable_ratelimit();
1138 unlock_policy_rwsem_write(cpu);
1139 sysfs_remove_link(kobj, "cpufreq");
1146 #ifdef CONFIG_HOTPLUG_CPU
1147 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1151 /* if we have other CPUs still registered, we need to unlink them,
1152 * or else wait_for_completion below will lock up. Clean the
1153 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1154 * the sysfs links afterwards.
1156 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1157 for_each_cpu(j, data->cpus) {
1160 per_cpu(cpufreq_cpu_data, j) = NULL;
1164 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1166 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1167 for_each_cpu(j, data->cpus) {
1170 dprintk("removing link for cpu %u\n", j);
1171 #ifdef CONFIG_HOTPLUG_CPU
1172 strncpy(per_cpu(cpufreq_cpu_governor, j),
1173 data->governor->name, CPUFREQ_NAME_LEN);
1175 cpu_sys_dev = get_cpu_sysdev(j);
1176 kobj = &cpu_sys_dev->kobj;
1177 unlock_policy_rwsem_write(cpu);
1178 sysfs_remove_link(kobj, "cpufreq");
1179 lock_policy_rwsem_write(cpu);
1180 cpufreq_cpu_put(data);
1184 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1187 if (cpufreq_driver->target)
1188 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1191 cmp = &data->kobj_unregister;
1192 unlock_policy_rwsem_write(cpu);
1195 /* we need to make sure that the underlying kobj is actually
1196 * not referenced anymore by anybody before we proceed with
1199 dprintk("waiting for dropping of refcount\n");
1200 wait_for_completion(cmp);
1201 dprintk("wait complete\n");
1203 lock_policy_rwsem_write(cpu);
1204 if (cpufreq_driver->exit)
1205 cpufreq_driver->exit(data);
1206 unlock_policy_rwsem_write(cpu);
1208 free_cpumask_var(data->related_cpus);
1209 free_cpumask_var(data->cpus);
1211 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1213 cpufreq_debug_enable_ratelimit();
1218 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1220 unsigned int cpu = sys_dev->id;
1223 if (cpu_is_offline(cpu))
1226 if (unlikely(lock_policy_rwsem_write(cpu)))
1229 retval = __cpufreq_remove_dev(sys_dev);
1234 static void handle_update(struct work_struct *work)
1236 struct cpufreq_policy *policy =
1237 container_of(work, struct cpufreq_policy, update);
1238 unsigned int cpu = policy->cpu;
1239 dprintk("handle_update for cpu %u called\n", cpu);
1240 cpufreq_update_policy(cpu);
1244 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1246 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1247 * @new_freq: CPU frequency the CPU actually runs at
1249 * We adjust to current frequency first, and need to clean up later.
1250 * So either call to cpufreq_update_policy() or schedule handle_update()).
1252 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1253 unsigned int new_freq)
1255 struct cpufreq_freqs freqs;
1257 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1258 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1261 freqs.old = old_freq;
1262 freqs.new = new_freq;
1263 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1264 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1269 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1272 * This is the last known freq, without actually getting it from the driver.
1273 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1275 unsigned int cpufreq_quick_get(unsigned int cpu)
1277 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1278 unsigned int ret_freq = 0;
1281 ret_freq = policy->cur;
1282 cpufreq_cpu_put(policy);
1287 EXPORT_SYMBOL(cpufreq_quick_get);
1290 static unsigned int __cpufreq_get(unsigned int cpu)
1292 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1293 unsigned int ret_freq = 0;
1295 if (!cpufreq_driver->get)
1298 ret_freq = cpufreq_driver->get(cpu);
1300 if (ret_freq && policy->cur &&
1301 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1302 /* verify no discrepancy between actual and
1303 saved value exists */
1304 if (unlikely(ret_freq != policy->cur)) {
1305 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1306 schedule_work(&policy->update);
1314 * cpufreq_get - get the current CPU frequency (in kHz)
1317 * Get the CPU current (static) CPU frequency
1319 unsigned int cpufreq_get(unsigned int cpu)
1321 unsigned int ret_freq = 0;
1322 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1327 if (unlikely(lock_policy_rwsem_read(cpu)))
1330 ret_freq = __cpufreq_get(cpu);
1332 unlock_policy_rwsem_read(cpu);
1335 cpufreq_cpu_put(policy);
1339 EXPORT_SYMBOL(cpufreq_get);
1343 * cpufreq_suspend - let the low level driver prepare for suspend
1346 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1350 int cpu = sysdev->id;
1351 struct cpufreq_policy *cpu_policy;
1353 dprintk("suspending cpu %u\n", cpu);
1355 if (!cpu_online(cpu))
1358 /* we may be lax here as interrupts are off. Nonetheless
1359 * we need to grab the correct cpu policy, as to check
1360 * whether we really run on this CPU.
1363 cpu_policy = cpufreq_cpu_get(cpu);
1367 /* only handle each CPU group once */
1368 if (unlikely(cpu_policy->cpu != cpu))
1371 if (cpufreq_driver->suspend) {
1372 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1374 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1375 "step on CPU %u\n", cpu_policy->cpu);
1379 cpufreq_cpu_put(cpu_policy);
1384 * cpufreq_resume - restore proper CPU frequency handling after resume
1386 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1387 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1388 * restored. It will verify that the current freq is in sync with
1389 * what we believe it to be. This is a bit later than when it
1390 * should be, but nonethteless it's better than calling
1391 * cpufreq_driver->get() here which might re-enable interrupts...
1393 static int cpufreq_resume(struct sys_device *sysdev)
1397 int cpu = sysdev->id;
1398 struct cpufreq_policy *cpu_policy;
1400 dprintk("resuming cpu %u\n", cpu);
1402 if (!cpu_online(cpu))
1405 /* we may be lax here as interrupts are off. Nonetheless
1406 * we need to grab the correct cpu policy, as to check
1407 * whether we really run on this CPU.
1410 cpu_policy = cpufreq_cpu_get(cpu);
1414 /* only handle each CPU group once */
1415 if (unlikely(cpu_policy->cpu != cpu))
1418 if (cpufreq_driver->resume) {
1419 ret = cpufreq_driver->resume(cpu_policy);
1421 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1422 "step on CPU %u\n", cpu_policy->cpu);
1427 schedule_work(&cpu_policy->update);
1430 cpufreq_cpu_put(cpu_policy);
1434 static struct sysdev_driver cpufreq_sysdev_driver = {
1435 .add = cpufreq_add_dev,
1436 .remove = cpufreq_remove_dev,
1437 .suspend = cpufreq_suspend,
1438 .resume = cpufreq_resume,
1442 /*********************************************************************
1443 * NOTIFIER LISTS INTERFACE *
1444 *********************************************************************/
1447 * cpufreq_register_notifier - register a driver with cpufreq
1448 * @nb: notifier function to register
1449 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1451 * Add a driver to one of two lists: either a list of drivers that
1452 * are notified about clock rate changes (once before and once after
1453 * the transition), or a list of drivers that are notified about
1454 * changes in cpufreq policy.
1456 * This function may sleep, and has the same return conditions as
1457 * blocking_notifier_chain_register.
1459 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1463 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1466 case CPUFREQ_TRANSITION_NOTIFIER:
1467 ret = srcu_notifier_chain_register(
1468 &cpufreq_transition_notifier_list, nb);
1470 case CPUFREQ_POLICY_NOTIFIER:
1471 ret = blocking_notifier_chain_register(
1472 &cpufreq_policy_notifier_list, nb);
1480 EXPORT_SYMBOL(cpufreq_register_notifier);
1484 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1485 * @nb: notifier block to be unregistered
1486 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1488 * Remove a driver from the CPU frequency notifier list.
1490 * This function may sleep, and has the same return conditions as
1491 * blocking_notifier_chain_unregister.
1493 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1498 case CPUFREQ_TRANSITION_NOTIFIER:
1499 ret = srcu_notifier_chain_unregister(
1500 &cpufreq_transition_notifier_list, nb);
1502 case CPUFREQ_POLICY_NOTIFIER:
1503 ret = blocking_notifier_chain_unregister(
1504 &cpufreq_policy_notifier_list, nb);
1512 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1515 /*********************************************************************
1517 *********************************************************************/
1520 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1521 unsigned int target_freq,
1522 unsigned int relation)
1524 int retval = -EINVAL;
1526 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1527 target_freq, relation);
1528 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1529 retval = cpufreq_driver->target(policy, target_freq, relation);
1533 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1535 int cpufreq_driver_target(struct cpufreq_policy *policy,
1536 unsigned int target_freq,
1537 unsigned int relation)
1541 policy = cpufreq_cpu_get(policy->cpu);
1545 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1548 ret = __cpufreq_driver_target(policy, target_freq, relation);
1550 unlock_policy_rwsem_write(policy->cpu);
1553 cpufreq_cpu_put(policy);
1557 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1559 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1563 policy = cpufreq_cpu_get(policy->cpu);
1567 if (cpu_online(cpu) && cpufreq_driver->getavg)
1568 ret = cpufreq_driver->getavg(policy, cpu);
1570 cpufreq_cpu_put(policy);
1573 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1576 * when "event" is CPUFREQ_GOV_LIMITS
1579 static int __cpufreq_governor(struct cpufreq_policy *policy,
1584 /* Only must be defined when default governor is known to have latency
1585 restrictions, like e.g. conservative or ondemand.
1586 That this is the case is already ensured in Kconfig
1588 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1589 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1591 struct cpufreq_governor *gov = NULL;
1594 if (policy->governor->max_transition_latency &&
1595 policy->cpuinfo.transition_latency >
1596 policy->governor->max_transition_latency) {
1600 printk(KERN_WARNING "%s governor failed, too long"
1601 " transition latency of HW, fallback"
1602 " to %s governor\n",
1603 policy->governor->name,
1605 policy->governor = gov;
1609 if (!try_module_get(policy->governor->owner))
1612 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1613 policy->cpu, event);
1614 ret = policy->governor->governor(policy, event);
1616 /* we keep one module reference alive for
1617 each CPU governed by this CPU */
1618 if ((event != CPUFREQ_GOV_START) || ret)
1619 module_put(policy->governor->owner);
1620 if ((event == CPUFREQ_GOV_STOP) && !ret)
1621 module_put(policy->governor->owner);
1627 int cpufreq_register_governor(struct cpufreq_governor *governor)
1634 mutex_lock(&cpufreq_governor_mutex);
1637 if (__find_governor(governor->name) == NULL) {
1639 list_add(&governor->governor_list, &cpufreq_governor_list);
1642 mutex_unlock(&cpufreq_governor_mutex);
1645 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1648 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1650 #ifdef CONFIG_HOTPLUG_CPU
1657 #ifdef CONFIG_HOTPLUG_CPU
1658 for_each_present_cpu(cpu) {
1659 if (cpu_online(cpu))
1661 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1662 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1666 mutex_lock(&cpufreq_governor_mutex);
1667 list_del(&governor->governor_list);
1668 mutex_unlock(&cpufreq_governor_mutex);
1671 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1675 /*********************************************************************
1676 * POLICY INTERFACE *
1677 *********************************************************************/
1680 * cpufreq_get_policy - get the current cpufreq_policy
1681 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1684 * Reads the current cpufreq policy.
1686 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1688 struct cpufreq_policy *cpu_policy;
1692 cpu_policy = cpufreq_cpu_get(cpu);
1696 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1698 cpufreq_cpu_put(cpu_policy);
1701 EXPORT_SYMBOL(cpufreq_get_policy);
1705 * data : current policy.
1706 * policy : policy to be set.
1708 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1709 struct cpufreq_policy *policy)
1713 cpufreq_debug_disable_ratelimit();
1714 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1715 policy->min, policy->max);
1717 memcpy(&policy->cpuinfo, &data->cpuinfo,
1718 sizeof(struct cpufreq_cpuinfo));
1720 if (policy->min > data->max || policy->max < data->min) {
1725 /* verify the cpu speed can be set within this limit */
1726 ret = cpufreq_driver->verify(policy);
1730 /* adjust if necessary - all reasons */
1731 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1732 CPUFREQ_ADJUST, policy);
1734 /* adjust if necessary - hardware incompatibility*/
1735 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1736 CPUFREQ_INCOMPATIBLE, policy);
1738 /* verify the cpu speed can be set within this limit,
1739 which might be different to the first one */
1740 ret = cpufreq_driver->verify(policy);
1744 /* notification of the new policy */
1745 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1746 CPUFREQ_NOTIFY, policy);
1748 data->min = policy->min;
1749 data->max = policy->max;
1751 dprintk("new min and max freqs are %u - %u kHz\n",
1752 data->min, data->max);
1754 if (cpufreq_driver->setpolicy) {
1755 data->policy = policy->policy;
1756 dprintk("setting range\n");
1757 ret = cpufreq_driver->setpolicy(policy);
1759 if (policy->governor != data->governor) {
1760 /* save old, working values */
1761 struct cpufreq_governor *old_gov = data->governor;
1763 dprintk("governor switch\n");
1765 /* end old governor */
1767 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1769 /* start new governor */
1770 data->governor = policy->governor;
1771 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1772 /* new governor failed, so re-start old one */
1773 dprintk("starting governor %s failed\n",
1774 data->governor->name);
1776 data->governor = old_gov;
1777 __cpufreq_governor(data,
1783 /* might be a policy change, too, so fall through */
1785 dprintk("governor: change or update limits\n");
1786 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1790 cpufreq_debug_enable_ratelimit();
1795 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1796 * @cpu: CPU which shall be re-evaluated
1798 * Usefull for policy notifiers which have different necessities
1799 * at different times.
1801 int cpufreq_update_policy(unsigned int cpu)
1803 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1804 struct cpufreq_policy policy;
1812 if (unlikely(lock_policy_rwsem_write(cpu))) {
1817 dprintk("updating policy for CPU %u\n", cpu);
1818 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1819 policy.min = data->user_policy.min;
1820 policy.max = data->user_policy.max;
1821 policy.policy = data->user_policy.policy;
1822 policy.governor = data->user_policy.governor;
1824 /* BIOS might change freq behind our back
1825 -> ask driver for current freq and notify governors about a change */
1826 if (cpufreq_driver->get) {
1827 policy.cur = cpufreq_driver->get(cpu);
1829 dprintk("Driver did not initialize current freq");
1830 data->cur = policy.cur;
1832 if (data->cur != policy.cur)
1833 cpufreq_out_of_sync(cpu, data->cur,
1838 ret = __cpufreq_set_policy(data, &policy);
1840 unlock_policy_rwsem_write(cpu);
1843 cpufreq_cpu_put(data);
1847 EXPORT_SYMBOL(cpufreq_update_policy);
1849 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1850 unsigned long action, void *hcpu)
1852 unsigned int cpu = (unsigned long)hcpu;
1853 struct sys_device *sys_dev;
1855 sys_dev = get_cpu_sysdev(cpu);
1859 case CPU_ONLINE_FROZEN:
1860 cpufreq_add_dev(sys_dev);
1862 case CPU_DOWN_PREPARE:
1863 case CPU_DOWN_PREPARE_FROZEN:
1864 if (unlikely(lock_policy_rwsem_write(cpu)))
1867 __cpufreq_remove_dev(sys_dev);
1869 case CPU_DOWN_FAILED:
1870 case CPU_DOWN_FAILED_FROZEN:
1871 cpufreq_add_dev(sys_dev);
1878 static struct notifier_block __refdata cpufreq_cpu_notifier =
1880 .notifier_call = cpufreq_cpu_callback,
1883 /*********************************************************************
1884 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1885 *********************************************************************/
1888 * cpufreq_register_driver - register a CPU Frequency driver
1889 * @driver_data: A struct cpufreq_driver containing the values#
1890 * submitted by the CPU Frequency driver.
1892 * Registers a CPU Frequency driver to this core code. This code
1893 * returns zero on success, -EBUSY when another driver got here first
1894 * (and isn't unregistered in the meantime).
1897 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1899 unsigned long flags;
1902 if (!driver_data || !driver_data->verify || !driver_data->init ||
1903 ((!driver_data->setpolicy) && (!driver_data->target)))
1906 dprintk("trying to register driver %s\n", driver_data->name);
1908 if (driver_data->setpolicy)
1909 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1911 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1912 if (cpufreq_driver) {
1913 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1916 cpufreq_driver = driver_data;
1917 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1919 ret = sysdev_driver_register(&cpu_sysdev_class,
1920 &cpufreq_sysdev_driver);
1922 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1926 /* check for at least one working CPU */
1927 for (i = 0; i < nr_cpu_ids; i++)
1928 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1933 /* if all ->init() calls failed, unregister */
1935 dprintk("no CPU initialized for driver %s\n",
1937 sysdev_driver_unregister(&cpu_sysdev_class,
1938 &cpufreq_sysdev_driver);
1940 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1941 cpufreq_driver = NULL;
1942 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1947 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1948 dprintk("driver %s up and running\n", driver_data->name);
1949 cpufreq_debug_enable_ratelimit();
1954 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1958 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1960 * Unregister the current CPUFreq driver. Only call this if you have
1961 * the right to do so, i.e. if you have succeeded in initialising before!
1962 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1963 * currently not initialised.
1965 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1967 unsigned long flags;
1969 cpufreq_debug_disable_ratelimit();
1971 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1972 cpufreq_debug_enable_ratelimit();
1976 dprintk("unregistering driver %s\n", driver->name);
1978 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1979 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1981 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1982 cpufreq_driver = NULL;
1983 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1987 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1989 static int __init cpufreq_core_init(void)
1993 for_each_possible_cpu(cpu) {
1994 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1995 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1998 cpufreq_global_kobject = kobject_create_and_add("cpufreq",
1999 &cpu_sysdev_class.kset.kobj);
2000 BUG_ON(!cpufreq_global_kobject);
2004 core_initcall(cpufreq_core_init);