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, 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(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(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(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);
650 #define define_one_ro(_name) \
651 static struct freq_attr _name = \
652 __ATTR(_name, 0444, show_##_name, NULL)
654 #define define_one_ro0400(_name) \
655 static struct freq_attr _name = \
656 __ATTR(_name, 0400, show_##_name, NULL)
658 #define define_one_rw(_name) \
659 static struct freq_attr _name = \
660 __ATTR(_name, 0644, show_##_name, store_##_name)
662 define_one_ro0400(cpuinfo_cur_freq);
663 define_one_ro(cpuinfo_min_freq);
664 define_one_ro(cpuinfo_max_freq);
665 define_one_ro(cpuinfo_transition_latency);
666 define_one_ro(scaling_available_governors);
667 define_one_ro(scaling_driver);
668 define_one_ro(scaling_cur_freq);
669 define_one_ro(related_cpus);
670 define_one_ro(affected_cpus);
671 define_one_rw(scaling_min_freq);
672 define_one_rw(scaling_max_freq);
673 define_one_rw(scaling_governor);
674 define_one_rw(scaling_setspeed);
676 static struct attribute *default_attrs[] = {
677 &cpuinfo_min_freq.attr,
678 &cpuinfo_max_freq.attr,
679 &cpuinfo_transition_latency.attr,
680 &scaling_min_freq.attr,
681 &scaling_max_freq.attr,
684 &scaling_governor.attr,
685 &scaling_driver.attr,
686 &scaling_available_governors.attr,
687 &scaling_setspeed.attr,
691 struct kobject *cpufreq_global_kobject;
692 EXPORT_SYMBOL(cpufreq_global_kobject);
694 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
695 #define to_attr(a) container_of(a, struct freq_attr, attr)
697 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
699 struct cpufreq_policy *policy = to_policy(kobj);
700 struct freq_attr *fattr = to_attr(attr);
701 ssize_t ret = -EINVAL;
702 policy = cpufreq_cpu_get(policy->cpu);
706 if (lock_policy_rwsem_read(policy->cpu) < 0)
710 ret = fattr->show(policy, buf);
714 unlock_policy_rwsem_read(policy->cpu);
716 cpufreq_cpu_put(policy);
721 static ssize_t store(struct kobject *kobj, struct attribute *attr,
722 const char *buf, size_t count)
724 struct cpufreq_policy *policy = to_policy(kobj);
725 struct freq_attr *fattr = to_attr(attr);
726 ssize_t ret = -EINVAL;
727 policy = cpufreq_cpu_get(policy->cpu);
731 if (lock_policy_rwsem_write(policy->cpu) < 0)
735 ret = fattr->store(policy, buf, count);
739 unlock_policy_rwsem_write(policy->cpu);
741 cpufreq_cpu_put(policy);
746 static void cpufreq_sysfs_release(struct kobject *kobj)
748 struct cpufreq_policy *policy = to_policy(kobj);
749 dprintk("last reference is dropped\n");
750 complete(&policy->kobj_unregister);
753 static struct sysfs_ops sysfs_ops = {
758 static struct kobj_type ktype_cpufreq = {
759 .sysfs_ops = &sysfs_ops,
760 .default_attrs = default_attrs,
761 .release = cpufreq_sysfs_release,
768 * Positive: When we have a managed CPU and the sysfs got symlinked
770 int cpufreq_add_dev_policy(unsigned int cpu, struct cpufreq_policy *policy,
771 struct sys_device *sys_dev)
777 #ifdef CONFIG_HOTPLUG_CPU
778 struct cpufreq_governor *gov;
780 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
782 policy->governor = gov;
783 dprintk("Restoring governor %s for cpu %d\n",
784 policy->governor->name, cpu);
788 for_each_cpu(j, policy->cpus) {
789 struct cpufreq_policy *managed_policy;
794 /* Check for existing affected CPUs.
795 * They may not be aware of it due to CPU Hotplug.
796 * cpufreq_cpu_put is called when the device is removed
797 * in __cpufreq_remove_dev()
799 managed_policy = cpufreq_cpu_get(j);
800 if (unlikely(managed_policy)) {
802 /* Set proper policy_cpu */
803 unlock_policy_rwsem_write(cpu);
804 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
806 if (lock_policy_rwsem_write(cpu) < 0) {
807 /* Should not go through policy unlock path */
808 if (cpufreq_driver->exit)
809 cpufreq_driver->exit(policy);
810 cpufreq_cpu_put(managed_policy);
814 spin_lock_irqsave(&cpufreq_driver_lock, flags);
815 cpumask_copy(managed_policy->cpus, policy->cpus);
816 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
817 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
819 dprintk("CPU already managed, adding link\n");
820 ret = sysfs_create_link(&sys_dev->kobj,
821 &managed_policy->kobj,
824 cpufreq_cpu_put(managed_policy);
826 * Success. We only needed to be added to the mask.
827 * Call driver->exit() because only the cpu parent of
828 * the kobj needed to call init().
830 if (cpufreq_driver->exit)
831 cpufreq_driver->exit(policy);
844 /* symlink affected CPUs */
845 int cpufreq_add_dev_symlink(unsigned int cpu, struct cpufreq_policy *policy)
850 for_each_cpu(j, policy->cpus) {
851 struct cpufreq_policy *managed_policy;
852 struct sys_device *cpu_sys_dev;
859 dprintk("CPU %u already managed, adding link\n", j);
860 managed_policy = cpufreq_cpu_get(cpu);
861 cpu_sys_dev = get_cpu_sysdev(j);
862 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
865 cpufreq_cpu_put(managed_policy);
872 int cpufreq_add_dev_interface(unsigned int cpu, struct cpufreq_policy *policy,
873 struct sys_device *sys_dev)
875 struct cpufreq_policy new_policy;
876 struct freq_attr **drv_attr;
881 /* prepare interface data */
882 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
883 &sys_dev->kobj, "cpufreq");
887 /* set up files for this cpu device */
888 drv_attr = cpufreq_driver->attr;
889 while ((drv_attr) && (*drv_attr)) {
890 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
892 goto err_out_kobj_put;
895 if (cpufreq_driver->get) {
896 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
898 goto err_out_kobj_put;
900 if (cpufreq_driver->target) {
901 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
903 goto err_out_kobj_put;
906 spin_lock_irqsave(&cpufreq_driver_lock, flags);
907 for_each_cpu(j, policy->cpus) {
910 per_cpu(cpufreq_cpu_data, j) = policy;
911 per_cpu(policy_cpu, j) = policy->cpu;
913 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
915 ret = cpufreq_add_dev_symlink(cpu, policy);
917 goto err_out_kobj_put;
919 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
920 /* assure that the starting sequence is run in __cpufreq_set_policy */
921 policy->governor = NULL;
923 /* set default policy */
924 ret = __cpufreq_set_policy(policy, &new_policy);
925 policy->user_policy.policy = policy->policy;
926 policy->user_policy.governor = policy->governor;
929 dprintk("setting policy failed\n");
930 if (cpufreq_driver->exit)
931 cpufreq_driver->exit(policy);
936 kobject_put(&policy->kobj);
937 wait_for_completion(&policy->kobj_unregister);
943 * cpufreq_add_dev - add a CPU device
945 * Adds the cpufreq interface for a CPU device.
947 * The Oracle says: try running cpufreq registration/unregistration concurrently
948 * with with cpu hotplugging and all hell will break loose. Tried to clean this
949 * mess up, but more thorough testing is needed. - Mathieu
951 static int cpufreq_add_dev(struct sys_device *sys_dev)
953 unsigned int cpu = sys_dev->id;
954 int ret = 0, found = 0;
955 struct cpufreq_policy *policy;
958 #ifdef CONFIG_HOTPLUG_CPU
962 if (cpu_is_offline(cpu))
965 cpufreq_debug_disable_ratelimit();
966 dprintk("adding CPU %u\n", cpu);
969 /* check whether a different CPU already registered this
970 * CPU because it is in the same boat. */
971 policy = cpufreq_cpu_get(cpu);
972 if (unlikely(policy)) {
973 cpufreq_cpu_put(policy);
974 cpufreq_debug_enable_ratelimit();
979 if (!try_module_get(cpufreq_driver->owner)) {
985 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
989 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
990 goto err_free_policy;
992 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
993 goto err_free_cpumask;
996 cpumask_copy(policy->cpus, cpumask_of(cpu));
998 /* Initially set CPU itself as the policy_cpu */
999 per_cpu(policy_cpu, cpu) = cpu;
1000 ret = (lock_policy_rwsem_write(cpu) < 0);
1003 init_completion(&policy->kobj_unregister);
1004 INIT_WORK(&policy->update, handle_update);
1006 /* Set governor before ->init, so that driver could check it */
1007 #ifdef CONFIG_HOTPLUG_CPU
1008 for_each_online_cpu(sibling) {
1009 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
1010 if (cp && cp->governor &&
1011 (cpumask_test_cpu(cpu, cp->related_cpus))) {
1012 policy->governor = cp->governor;
1019 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
1020 /* call driver. From then on the cpufreq must be able
1021 * to accept all calls to ->verify and ->setpolicy for this CPU
1023 ret = cpufreq_driver->init(policy);
1025 dprintk("initialization failed\n");
1026 goto err_unlock_policy;
1028 policy->user_policy.min = policy->min;
1029 policy->user_policy.max = policy->max;
1031 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1032 CPUFREQ_START, policy);
1034 ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
1037 /* This is a managed cpu, symlink created,
1040 goto err_unlock_policy;
1043 ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
1045 goto err_out_unregister;
1047 unlock_policy_rwsem_write(cpu);
1049 kobject_uevent(&policy->kobj, KOBJ_ADD);
1050 module_put(cpufreq_driver->owner);
1051 dprintk("initialization complete\n");
1052 cpufreq_debug_enable_ratelimit();
1058 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1059 for_each_cpu(j, policy->cpus)
1060 per_cpu(cpufreq_cpu_data, j) = NULL;
1061 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1063 kobject_put(&policy->kobj);
1064 wait_for_completion(&policy->kobj_unregister);
1067 unlock_policy_rwsem_write(cpu);
1069 free_cpumask_var(policy->cpus);
1073 module_put(cpufreq_driver->owner);
1075 cpufreq_debug_enable_ratelimit();
1081 * __cpufreq_remove_dev - remove a CPU device
1083 * Removes the cpufreq interface for a CPU device.
1084 * Caller should already have policy_rwsem in write mode for this CPU.
1085 * This routine frees the rwsem before returning.
1087 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1089 unsigned int cpu = sys_dev->id;
1090 unsigned long flags;
1091 struct cpufreq_policy *data;
1093 struct sys_device *cpu_sys_dev;
1097 cpufreq_debug_disable_ratelimit();
1098 dprintk("unregistering CPU %u\n", cpu);
1100 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1101 data = per_cpu(cpufreq_cpu_data, cpu);
1104 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1105 cpufreq_debug_enable_ratelimit();
1106 unlock_policy_rwsem_write(cpu);
1109 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1113 /* if this isn't the CPU which is the parent of the kobj, we
1114 * only need to unlink, put and exit
1116 if (unlikely(cpu != data->cpu)) {
1117 dprintk("removing link\n");
1118 cpumask_clear_cpu(cpu, data->cpus);
1119 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1120 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
1121 cpufreq_cpu_put(data);
1122 cpufreq_debug_enable_ratelimit();
1123 unlock_policy_rwsem_write(cpu);
1130 #ifdef CONFIG_HOTPLUG_CPU
1131 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1135 /* if we have other CPUs still registered, we need to unlink them,
1136 * or else wait_for_completion below will lock up. Clean the
1137 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1138 * the sysfs links afterwards.
1140 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1141 for_each_cpu(j, data->cpus) {
1144 per_cpu(cpufreq_cpu_data, j) = NULL;
1148 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1150 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1151 for_each_cpu(j, data->cpus) {
1154 dprintk("removing link for cpu %u\n", j);
1155 #ifdef CONFIG_HOTPLUG_CPU
1156 strncpy(per_cpu(cpufreq_cpu_governor, j),
1157 data->governor->name, CPUFREQ_NAME_LEN);
1159 cpu_sys_dev = get_cpu_sysdev(j);
1160 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1161 cpufreq_cpu_put(data);
1165 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1168 if (cpufreq_driver->target)
1169 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1171 kobject_put(&data->kobj);
1173 /* we need to make sure that the underlying kobj is actually
1174 * not referenced anymore by anybody before we proceed with
1177 dprintk("waiting for dropping of refcount\n");
1178 wait_for_completion(&data->kobj_unregister);
1179 dprintk("wait complete\n");
1181 if (cpufreq_driver->exit)
1182 cpufreq_driver->exit(data);
1184 unlock_policy_rwsem_write(cpu);
1186 free_cpumask_var(data->related_cpus);
1187 free_cpumask_var(data->cpus);
1189 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1191 cpufreq_debug_enable_ratelimit();
1196 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1198 unsigned int cpu = sys_dev->id;
1201 if (cpu_is_offline(cpu))
1204 if (unlikely(lock_policy_rwsem_write(cpu)))
1207 retval = __cpufreq_remove_dev(sys_dev);
1212 static void handle_update(struct work_struct *work)
1214 struct cpufreq_policy *policy =
1215 container_of(work, struct cpufreq_policy, update);
1216 unsigned int cpu = policy->cpu;
1217 dprintk("handle_update for cpu %u called\n", cpu);
1218 cpufreq_update_policy(cpu);
1222 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1224 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1225 * @new_freq: CPU frequency the CPU actually runs at
1227 * We adjust to current frequency first, and need to clean up later.
1228 * So either call to cpufreq_update_policy() or schedule handle_update()).
1230 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1231 unsigned int new_freq)
1233 struct cpufreq_freqs freqs;
1235 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1236 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1239 freqs.old = old_freq;
1240 freqs.new = new_freq;
1241 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1242 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1247 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1250 * This is the last known freq, without actually getting it from the driver.
1251 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1253 unsigned int cpufreq_quick_get(unsigned int cpu)
1255 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1256 unsigned int ret_freq = 0;
1259 ret_freq = policy->cur;
1260 cpufreq_cpu_put(policy);
1265 EXPORT_SYMBOL(cpufreq_quick_get);
1268 static unsigned int __cpufreq_get(unsigned int cpu)
1270 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1271 unsigned int ret_freq = 0;
1273 if (!cpufreq_driver->get)
1276 ret_freq = cpufreq_driver->get(cpu);
1278 if (ret_freq && policy->cur &&
1279 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1280 /* verify no discrepancy between actual and
1281 saved value exists */
1282 if (unlikely(ret_freq != policy->cur)) {
1283 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1284 schedule_work(&policy->update);
1292 * cpufreq_get - get the current CPU frequency (in kHz)
1295 * Get the CPU current (static) CPU frequency
1297 unsigned int cpufreq_get(unsigned int cpu)
1299 unsigned int ret_freq = 0;
1300 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1305 if (unlikely(lock_policy_rwsem_read(cpu)))
1308 ret_freq = __cpufreq_get(cpu);
1310 unlock_policy_rwsem_read(cpu);
1313 cpufreq_cpu_put(policy);
1317 EXPORT_SYMBOL(cpufreq_get);
1321 * cpufreq_suspend - let the low level driver prepare for suspend
1324 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1328 int cpu = sysdev->id;
1329 struct cpufreq_policy *cpu_policy;
1331 dprintk("suspending cpu %u\n", cpu);
1333 if (!cpu_online(cpu))
1336 /* we may be lax here as interrupts are off. Nonetheless
1337 * we need to grab the correct cpu policy, as to check
1338 * whether we really run on this CPU.
1341 cpu_policy = cpufreq_cpu_get(cpu);
1345 /* only handle each CPU group once */
1346 if (unlikely(cpu_policy->cpu != cpu))
1349 if (cpufreq_driver->suspend) {
1350 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1352 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1353 "step on CPU %u\n", cpu_policy->cpu);
1357 cpufreq_cpu_put(cpu_policy);
1362 * cpufreq_resume - restore proper CPU frequency handling after resume
1364 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1365 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1366 * restored. It will verify that the current freq is in sync with
1367 * what we believe it to be. This is a bit later than when it
1368 * should be, but nonethteless it's better than calling
1369 * cpufreq_driver->get() here which might re-enable interrupts...
1371 static int cpufreq_resume(struct sys_device *sysdev)
1375 int cpu = sysdev->id;
1376 struct cpufreq_policy *cpu_policy;
1378 dprintk("resuming cpu %u\n", cpu);
1380 if (!cpu_online(cpu))
1383 /* we may be lax here as interrupts are off. Nonetheless
1384 * we need to grab the correct cpu policy, as to check
1385 * whether we really run on this CPU.
1388 cpu_policy = cpufreq_cpu_get(cpu);
1392 /* only handle each CPU group once */
1393 if (unlikely(cpu_policy->cpu != cpu))
1396 if (cpufreq_driver->resume) {
1397 ret = cpufreq_driver->resume(cpu_policy);
1399 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1400 "step on CPU %u\n", cpu_policy->cpu);
1405 schedule_work(&cpu_policy->update);
1408 cpufreq_cpu_put(cpu_policy);
1412 static struct sysdev_driver cpufreq_sysdev_driver = {
1413 .add = cpufreq_add_dev,
1414 .remove = cpufreq_remove_dev,
1415 .suspend = cpufreq_suspend,
1416 .resume = cpufreq_resume,
1420 /*********************************************************************
1421 * NOTIFIER LISTS INTERFACE *
1422 *********************************************************************/
1425 * cpufreq_register_notifier - register a driver with cpufreq
1426 * @nb: notifier function to register
1427 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1429 * Add a driver to one of two lists: either a list of drivers that
1430 * are notified about clock rate changes (once before and once after
1431 * the transition), or a list of drivers that are notified about
1432 * changes in cpufreq policy.
1434 * This function may sleep, and has the same return conditions as
1435 * blocking_notifier_chain_register.
1437 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1441 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1444 case CPUFREQ_TRANSITION_NOTIFIER:
1445 ret = srcu_notifier_chain_register(
1446 &cpufreq_transition_notifier_list, nb);
1448 case CPUFREQ_POLICY_NOTIFIER:
1449 ret = blocking_notifier_chain_register(
1450 &cpufreq_policy_notifier_list, nb);
1458 EXPORT_SYMBOL(cpufreq_register_notifier);
1462 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1463 * @nb: notifier block to be unregistered
1464 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1466 * Remove a driver from the CPU frequency notifier list.
1468 * This function may sleep, and has the same return conditions as
1469 * blocking_notifier_chain_unregister.
1471 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1476 case CPUFREQ_TRANSITION_NOTIFIER:
1477 ret = srcu_notifier_chain_unregister(
1478 &cpufreq_transition_notifier_list, nb);
1480 case CPUFREQ_POLICY_NOTIFIER:
1481 ret = blocking_notifier_chain_unregister(
1482 &cpufreq_policy_notifier_list, nb);
1490 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1493 /*********************************************************************
1495 *********************************************************************/
1498 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1499 unsigned int target_freq,
1500 unsigned int relation)
1502 int retval = -EINVAL;
1504 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1505 target_freq, relation);
1506 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1507 retval = cpufreq_driver->target(policy, target_freq, relation);
1511 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1513 int cpufreq_driver_target(struct cpufreq_policy *policy,
1514 unsigned int target_freq,
1515 unsigned int relation)
1519 policy = cpufreq_cpu_get(policy->cpu);
1523 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1526 ret = __cpufreq_driver_target(policy, target_freq, relation);
1528 unlock_policy_rwsem_write(policy->cpu);
1531 cpufreq_cpu_put(policy);
1535 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1537 int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1541 policy = cpufreq_cpu_get(policy->cpu);
1545 if (cpu_online(cpu) && cpufreq_driver->getavg)
1546 ret = cpufreq_driver->getavg(policy, cpu);
1548 cpufreq_cpu_put(policy);
1551 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1554 * when "event" is CPUFREQ_GOV_LIMITS
1557 static int __cpufreq_governor(struct cpufreq_policy *policy,
1562 /* Only must be defined when default governor is known to have latency
1563 restrictions, like e.g. conservative or ondemand.
1564 That this is the case is already ensured in Kconfig
1566 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1567 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1569 struct cpufreq_governor *gov = NULL;
1572 if (policy->governor->max_transition_latency &&
1573 policy->cpuinfo.transition_latency >
1574 policy->governor->max_transition_latency) {
1578 printk(KERN_WARNING "%s governor failed, too long"
1579 " transition latency of HW, fallback"
1580 " to %s governor\n",
1581 policy->governor->name,
1583 policy->governor = gov;
1587 if (!try_module_get(policy->governor->owner))
1590 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1591 policy->cpu, event);
1592 ret = policy->governor->governor(policy, event);
1594 /* we keep one module reference alive for
1595 each CPU governed by this CPU */
1596 if ((event != CPUFREQ_GOV_START) || ret)
1597 module_put(policy->governor->owner);
1598 if ((event == CPUFREQ_GOV_STOP) && !ret)
1599 module_put(policy->governor->owner);
1605 int cpufreq_register_governor(struct cpufreq_governor *governor)
1612 mutex_lock(&cpufreq_governor_mutex);
1615 if (__find_governor(governor->name) == NULL) {
1617 list_add(&governor->governor_list, &cpufreq_governor_list);
1620 mutex_unlock(&cpufreq_governor_mutex);
1623 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1626 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1628 #ifdef CONFIG_HOTPLUG_CPU
1635 #ifdef CONFIG_HOTPLUG_CPU
1636 for_each_present_cpu(cpu) {
1637 if (cpu_online(cpu))
1639 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1640 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1644 mutex_lock(&cpufreq_governor_mutex);
1645 list_del(&governor->governor_list);
1646 mutex_unlock(&cpufreq_governor_mutex);
1649 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1653 /*********************************************************************
1654 * POLICY INTERFACE *
1655 *********************************************************************/
1658 * cpufreq_get_policy - get the current cpufreq_policy
1659 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1662 * Reads the current cpufreq policy.
1664 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1666 struct cpufreq_policy *cpu_policy;
1670 cpu_policy = cpufreq_cpu_get(cpu);
1674 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1676 cpufreq_cpu_put(cpu_policy);
1679 EXPORT_SYMBOL(cpufreq_get_policy);
1683 * data : current policy.
1684 * policy : policy to be set.
1686 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1687 struct cpufreq_policy *policy)
1691 cpufreq_debug_disable_ratelimit();
1692 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1693 policy->min, policy->max);
1695 memcpy(&policy->cpuinfo, &data->cpuinfo,
1696 sizeof(struct cpufreq_cpuinfo));
1698 if (policy->min > data->max || policy->max < data->min) {
1703 /* verify the cpu speed can be set within this limit */
1704 ret = cpufreq_driver->verify(policy);
1708 /* adjust if necessary - all reasons */
1709 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1710 CPUFREQ_ADJUST, policy);
1712 /* adjust if necessary - hardware incompatibility*/
1713 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1714 CPUFREQ_INCOMPATIBLE, policy);
1716 /* verify the cpu speed can be set within this limit,
1717 which might be different to the first one */
1718 ret = cpufreq_driver->verify(policy);
1722 /* notification of the new policy */
1723 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1724 CPUFREQ_NOTIFY, policy);
1726 data->min = policy->min;
1727 data->max = policy->max;
1729 dprintk("new min and max freqs are %u - %u kHz\n",
1730 data->min, data->max);
1732 if (cpufreq_driver->setpolicy) {
1733 data->policy = policy->policy;
1734 dprintk("setting range\n");
1735 ret = cpufreq_driver->setpolicy(policy);
1737 if (policy->governor != data->governor) {
1738 /* save old, working values */
1739 struct cpufreq_governor *old_gov = data->governor;
1741 dprintk("governor switch\n");
1743 /* end old governor */
1744 if (data->governor) {
1746 * Need to release the rwsem around governor
1747 * stop due to lock dependency between
1748 * cancel_delayed_work_sync and the read lock
1749 * taken in the delayed work handler.
1751 unlock_policy_rwsem_write(data->cpu);
1752 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1753 lock_policy_rwsem_write(data->cpu);
1756 /* start new governor */
1757 data->governor = policy->governor;
1758 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1759 /* new governor failed, so re-start old one */
1760 dprintk("starting governor %s failed\n",
1761 data->governor->name);
1763 data->governor = old_gov;
1764 __cpufreq_governor(data,
1770 /* might be a policy change, too, so fall through */
1772 dprintk("governor: change or update limits\n");
1773 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1777 cpufreq_debug_enable_ratelimit();
1782 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1783 * @cpu: CPU which shall be re-evaluated
1785 * Usefull for policy notifiers which have different necessities
1786 * at different times.
1788 int cpufreq_update_policy(unsigned int cpu)
1790 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1791 struct cpufreq_policy policy;
1799 if (unlikely(lock_policy_rwsem_write(cpu))) {
1804 dprintk("updating policy for CPU %u\n", cpu);
1805 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1806 policy.min = data->user_policy.min;
1807 policy.max = data->user_policy.max;
1808 policy.policy = data->user_policy.policy;
1809 policy.governor = data->user_policy.governor;
1811 /* BIOS might change freq behind our back
1812 -> ask driver for current freq and notify governors about a change */
1813 if (cpufreq_driver->get) {
1814 policy.cur = cpufreq_driver->get(cpu);
1816 dprintk("Driver did not initialize current freq");
1817 data->cur = policy.cur;
1819 if (data->cur != policy.cur)
1820 cpufreq_out_of_sync(cpu, data->cur,
1825 ret = __cpufreq_set_policy(data, &policy);
1827 unlock_policy_rwsem_write(cpu);
1830 cpufreq_cpu_put(data);
1834 EXPORT_SYMBOL(cpufreq_update_policy);
1836 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1837 unsigned long action, void *hcpu)
1839 unsigned int cpu = (unsigned long)hcpu;
1840 struct sys_device *sys_dev;
1842 sys_dev = get_cpu_sysdev(cpu);
1846 case CPU_ONLINE_FROZEN:
1847 cpufreq_add_dev(sys_dev);
1849 case CPU_DOWN_PREPARE:
1850 case CPU_DOWN_PREPARE_FROZEN:
1851 if (unlikely(lock_policy_rwsem_write(cpu)))
1854 __cpufreq_remove_dev(sys_dev);
1856 case CPU_DOWN_FAILED:
1857 case CPU_DOWN_FAILED_FROZEN:
1858 cpufreq_add_dev(sys_dev);
1865 static struct notifier_block __refdata cpufreq_cpu_notifier =
1867 .notifier_call = cpufreq_cpu_callback,
1870 /*********************************************************************
1871 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1872 *********************************************************************/
1875 * cpufreq_register_driver - register a CPU Frequency driver
1876 * @driver_data: A struct cpufreq_driver containing the values#
1877 * submitted by the CPU Frequency driver.
1879 * Registers a CPU Frequency driver to this core code. This code
1880 * returns zero on success, -EBUSY when another driver got here first
1881 * (and isn't unregistered in the meantime).
1884 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1886 unsigned long flags;
1889 if (!driver_data || !driver_data->verify || !driver_data->init ||
1890 ((!driver_data->setpolicy) && (!driver_data->target)))
1893 dprintk("trying to register driver %s\n", driver_data->name);
1895 if (driver_data->setpolicy)
1896 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1898 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1899 if (cpufreq_driver) {
1900 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1903 cpufreq_driver = driver_data;
1904 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1906 ret = sysdev_driver_register(&cpu_sysdev_class,
1907 &cpufreq_sysdev_driver);
1909 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1913 /* check for at least one working CPU */
1914 for (i = 0; i < nr_cpu_ids; i++)
1915 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1920 /* if all ->init() calls failed, unregister */
1922 dprintk("no CPU initialized for driver %s\n",
1924 sysdev_driver_unregister(&cpu_sysdev_class,
1925 &cpufreq_sysdev_driver);
1927 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1928 cpufreq_driver = NULL;
1929 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1934 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1935 dprintk("driver %s up and running\n", driver_data->name);
1936 cpufreq_debug_enable_ratelimit();
1941 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1945 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1947 * Unregister the current CPUFreq driver. Only call this if you have
1948 * the right to do so, i.e. if you have succeeded in initialising before!
1949 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1950 * currently not initialised.
1952 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1954 unsigned long flags;
1956 cpufreq_debug_disable_ratelimit();
1958 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1959 cpufreq_debug_enable_ratelimit();
1963 dprintk("unregistering driver %s\n", driver->name);
1965 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1966 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1968 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1969 cpufreq_driver = NULL;
1970 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1974 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1976 static int __init cpufreq_core_init(void)
1980 for_each_possible_cpu(cpu) {
1981 per_cpu(policy_cpu, cpu) = -1;
1982 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1985 cpufreq_global_kobject = kobject_create_and_add("cpufreq",
1986 &cpu_sysdev_class.kset.kobj);
1987 BUG_ON(!cpufreq_global_kobject);
1991 core_initcall(cpufreq_core_init);