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 struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
42 #ifdef CONFIG_HOTPLUG_CPU
43 /* This one keeps track of the previously set governor of a removed CPU */
44 static struct cpufreq_governor *cpufreq_cpu_governor[NR_CPUS];
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.
65 static DEFINE_PER_CPU(int, policy_cpu);
66 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
68 #define lock_policy_rwsem(mode, cpu) \
69 int lock_policy_rwsem_##mode \
72 int policy_cpu = per_cpu(policy_cpu, cpu); \
73 BUG_ON(policy_cpu == -1); \
74 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
75 if (unlikely(!cpu_online(cpu))) { \
76 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
83 lock_policy_rwsem(read, cpu);
84 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read);
86 lock_policy_rwsem(write, cpu);
87 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write);
89 void unlock_policy_rwsem_read(int cpu)
91 int policy_cpu = per_cpu(policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
95 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read);
97 void unlock_policy_rwsem_write(int cpu)
99 int policy_cpu = per_cpu(policy_cpu, cpu);
100 BUG_ON(policy_cpu == -1);
101 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
103 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write);
106 /* internal prototypes */
107 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
108 static unsigned int __cpufreq_get(unsigned int cpu);
109 static void handle_update(struct work_struct *work);
112 * Two notifier lists: the "policy" list is involved in the
113 * validation process for a new CPU frequency policy; the
114 * "transition" list for kernel code that needs to handle
115 * changes to devices when the CPU clock speed changes.
116 * The mutex locks both lists.
118 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
119 static struct srcu_notifier_head cpufreq_transition_notifier_list;
121 static int __init init_cpufreq_transition_notifier_list(void)
123 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
126 pure_initcall(init_cpufreq_transition_notifier_list);
128 static LIST_HEAD(cpufreq_governor_list);
129 static DEFINE_MUTEX (cpufreq_governor_mutex);
131 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
133 struct cpufreq_policy *data;
139 /* get the cpufreq driver */
140 spin_lock_irqsave(&cpufreq_driver_lock, flags);
145 if (!try_module_get(cpufreq_driver->owner))
150 data = cpufreq_cpu_data[cpu];
153 goto err_out_put_module;
155 if (!kobject_get(&data->kobj))
156 goto err_out_put_module;
158 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
162 module_put(cpufreq_driver->owner);
164 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
168 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
171 void cpufreq_cpu_put(struct cpufreq_policy *data)
173 kobject_put(&data->kobj);
174 module_put(cpufreq_driver->owner);
176 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
179 /*********************************************************************
180 * UNIFIED DEBUG HELPERS *
181 *********************************************************************/
182 #ifdef CONFIG_CPU_FREQ_DEBUG
184 /* what part(s) of the CPUfreq subsystem are debugged? */
185 static unsigned int debug;
187 /* is the debug output ratelimit'ed using printk_ratelimit? User can
188 * set or modify this value.
190 static unsigned int debug_ratelimit = 1;
192 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
193 * loading of a cpufreq driver, temporarily disabled when a new policy
194 * is set, and disabled upon cpufreq driver removal
196 static unsigned int disable_ratelimit = 1;
197 static DEFINE_SPINLOCK(disable_ratelimit_lock);
199 static void cpufreq_debug_enable_ratelimit(void)
203 spin_lock_irqsave(&disable_ratelimit_lock, flags);
204 if (disable_ratelimit)
206 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
209 static void cpufreq_debug_disable_ratelimit(void)
213 spin_lock_irqsave(&disable_ratelimit_lock, flags);
215 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
218 void cpufreq_debug_printk(unsigned int type, const char *prefix,
219 const char *fmt, ...)
228 spin_lock_irqsave(&disable_ratelimit_lock, flags);
229 if (!disable_ratelimit && debug_ratelimit
230 && !printk_ratelimit()) {
231 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
234 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
236 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
239 len += vsnprintf(&s[len], (256 - len), fmt, args);
247 EXPORT_SYMBOL(cpufreq_debug_printk);
250 module_param(debug, uint, 0644);
251 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
252 " 2 to debug drivers, and 4 to debug governors.");
254 module_param(debug_ratelimit, uint, 0644);
255 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
256 " set to 0 to disable ratelimiting.");
258 #else /* !CONFIG_CPU_FREQ_DEBUG */
260 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
261 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
263 #endif /* CONFIG_CPU_FREQ_DEBUG */
266 /*********************************************************************
267 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
268 *********************************************************************/
271 * adjust_jiffies - adjust the system "loops_per_jiffy"
273 * This function alters the system "loops_per_jiffy" for the clock
274 * speed change. Note that loops_per_jiffy cannot be updated on SMP
275 * systems as each CPU might be scaled differently. So, use the arch
276 * per-CPU loops_per_jiffy value wherever possible.
279 static unsigned long l_p_j_ref;
280 static unsigned int l_p_j_ref_freq;
282 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
284 if (ci->flags & CPUFREQ_CONST_LOOPS)
287 if (!l_p_j_ref_freq) {
288 l_p_j_ref = loops_per_jiffy;
289 l_p_j_ref_freq = ci->old;
290 dprintk("saving %lu as reference value for loops_per_jiffy; "
291 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
293 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
294 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
295 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
296 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
298 dprintk("scaling loops_per_jiffy to %lu "
299 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
303 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
311 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
312 * on frequency transition.
314 * This function calls the transition notifiers and the "adjust_jiffies"
315 * function. It is called twice on all CPU frequency changes that have
318 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
320 struct cpufreq_policy *policy;
322 BUG_ON(irqs_disabled());
324 freqs->flags = cpufreq_driver->flags;
325 dprintk("notification %u of frequency transition to %u kHz\n",
328 policy = cpufreq_cpu_data[freqs->cpu];
331 case CPUFREQ_PRECHANGE:
332 /* detect if the driver reported a value as "old frequency"
333 * which is not equal to what the cpufreq core thinks is
336 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
337 if ((policy) && (policy->cpu == freqs->cpu) &&
338 (policy->cur) && (policy->cur != freqs->old)) {
339 dprintk("Warning: CPU frequency is"
340 " %u, cpufreq assumed %u kHz.\n",
341 freqs->old, policy->cur);
342 freqs->old = policy->cur;
345 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
346 CPUFREQ_PRECHANGE, freqs);
347 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
350 case CPUFREQ_POSTCHANGE:
351 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
352 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
353 CPUFREQ_POSTCHANGE, freqs);
354 if (likely(policy) && likely(policy->cpu == freqs->cpu))
355 policy->cur = freqs->new;
359 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
363 /*********************************************************************
365 *********************************************************************/
367 static struct cpufreq_governor *__find_governor(const char *str_governor)
369 struct cpufreq_governor *t;
371 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
372 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN))
379 * cpufreq_parse_governor - parse a governor string
381 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
382 struct cpufreq_governor **governor)
389 if (cpufreq_driver->setpolicy) {
390 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
391 *policy = CPUFREQ_POLICY_PERFORMANCE;
393 } else if (!strnicmp(str_governor, "powersave",
395 *policy = CPUFREQ_POLICY_POWERSAVE;
398 } else if (cpufreq_driver->target) {
399 struct cpufreq_governor *t;
401 mutex_lock(&cpufreq_governor_mutex);
403 t = __find_governor(str_governor);
406 char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
412 mutex_unlock(&cpufreq_governor_mutex);
413 ret = request_module(name);
414 mutex_lock(&cpufreq_governor_mutex);
417 t = __find_governor(str_governor);
428 mutex_unlock(&cpufreq_governor_mutex);
435 /* drivers/base/cpu.c */
436 extern struct sysdev_class cpu_sysdev_class;
440 * cpufreq_per_cpu_attr_read() / show_##file_name() -
441 * print out cpufreq information
443 * Write out information from cpufreq_driver->policy[cpu]; object must be
447 #define show_one(file_name, object) \
448 static ssize_t show_##file_name \
449 (struct cpufreq_policy *policy, char *buf) \
451 return sprintf (buf, "%u\n", policy->object); \
454 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
455 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
456 show_one(scaling_min_freq, min);
457 show_one(scaling_max_freq, max);
458 show_one(scaling_cur_freq, cur);
460 static int __cpufreq_set_policy(struct cpufreq_policy *data,
461 struct cpufreq_policy *policy);
464 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
466 #define store_one(file_name, object) \
467 static ssize_t store_##file_name \
468 (struct cpufreq_policy *policy, const char *buf, size_t count) \
470 unsigned int ret = -EINVAL; \
471 struct cpufreq_policy new_policy; \
473 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
477 ret = sscanf (buf, "%u", &new_policy.object); \
481 ret = __cpufreq_set_policy(policy, &new_policy); \
482 policy->user_policy.object = policy->object; \
484 return ret ? ret : count; \
487 store_one(scaling_min_freq,min);
488 store_one(scaling_max_freq,max);
491 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
493 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
496 unsigned int cur_freq = __cpufreq_get(policy->cpu);
498 return sprintf(buf, "<unknown>");
499 return sprintf(buf, "%u\n", cur_freq);
504 * show_scaling_governor - show the current policy for the specified CPU
506 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
508 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
509 return sprintf(buf, "powersave\n");
510 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
511 return sprintf(buf, "performance\n");
512 else if (policy->governor)
513 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
519 * store_scaling_governor - store policy for the specified CPU
521 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
522 const char *buf, size_t count)
524 unsigned int ret = -EINVAL;
525 char str_governor[16];
526 struct cpufreq_policy new_policy;
528 ret = cpufreq_get_policy(&new_policy, policy->cpu);
532 ret = sscanf (buf, "%15s", str_governor);
536 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
537 &new_policy.governor))
540 /* Do not use cpufreq_set_policy here or the user_policy.max
541 will be wrongly overridden */
542 ret = __cpufreq_set_policy(policy, &new_policy);
544 policy->user_policy.policy = policy->policy;
545 policy->user_policy.governor = policy->governor;
554 * show_scaling_driver - show the cpufreq driver currently loaded
556 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
558 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
562 * show_scaling_available_governors - show the available CPUfreq governors
564 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
568 struct cpufreq_governor *t;
570 if (!cpufreq_driver->target) {
571 i += sprintf(buf, "performance powersave");
575 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
576 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
578 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
581 i += sprintf(&buf[i], "\n");
585 * show_affected_cpus - show the CPUs affected by each transition
587 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
592 for_each_cpu_mask(cpu, policy->cpus) {
594 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
595 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
596 if (i >= (PAGE_SIZE - 5))
599 i += sprintf(&buf[i], "\n");
603 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
604 const char *buf, size_t count)
606 unsigned int freq = 0;
609 if (!policy->governor->store_setspeed)
612 ret = sscanf(buf, "%u", &freq);
616 policy->governor->store_setspeed(policy, freq);
621 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
623 if (!policy->governor->show_setspeed)
624 return sprintf(buf, "<unsupported>\n");
626 return policy->governor->show_setspeed(policy, buf);
629 #define define_one_ro(_name) \
630 static struct freq_attr _name = \
631 __ATTR(_name, 0444, show_##_name, NULL)
633 #define define_one_ro0400(_name) \
634 static struct freq_attr _name = \
635 __ATTR(_name, 0400, show_##_name, NULL)
637 #define define_one_rw(_name) \
638 static struct freq_attr _name = \
639 __ATTR(_name, 0644, show_##_name, store_##_name)
641 define_one_ro0400(cpuinfo_cur_freq);
642 define_one_ro(cpuinfo_min_freq);
643 define_one_ro(cpuinfo_max_freq);
644 define_one_ro(scaling_available_governors);
645 define_one_ro(scaling_driver);
646 define_one_ro(scaling_cur_freq);
647 define_one_ro(affected_cpus);
648 define_one_rw(scaling_min_freq);
649 define_one_rw(scaling_max_freq);
650 define_one_rw(scaling_governor);
651 define_one_rw(scaling_setspeed);
653 static struct attribute *default_attrs[] = {
654 &cpuinfo_min_freq.attr,
655 &cpuinfo_max_freq.attr,
656 &scaling_min_freq.attr,
657 &scaling_max_freq.attr,
659 &scaling_governor.attr,
660 &scaling_driver.attr,
661 &scaling_available_governors.attr,
662 &scaling_setspeed.attr,
666 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
667 #define to_attr(a) container_of(a,struct freq_attr,attr)
669 static ssize_t show(struct kobject *kobj, struct attribute *attr ,char *buf)
671 struct cpufreq_policy *policy = to_policy(kobj);
672 struct freq_attr *fattr = to_attr(attr);
673 ssize_t ret = -EINVAL;
674 policy = cpufreq_cpu_get(policy->cpu);
678 if (lock_policy_rwsem_read(policy->cpu) < 0)
682 ret = fattr->show(policy, buf);
686 unlock_policy_rwsem_read(policy->cpu);
688 cpufreq_cpu_put(policy);
693 static ssize_t store(struct kobject *kobj, struct attribute *attr,
694 const char *buf, size_t count)
696 struct cpufreq_policy *policy = to_policy(kobj);
697 struct freq_attr *fattr = to_attr(attr);
698 ssize_t ret = -EINVAL;
699 policy = cpufreq_cpu_get(policy->cpu);
703 if (lock_policy_rwsem_write(policy->cpu) < 0)
707 ret = fattr->store(policy, buf, count);
711 unlock_policy_rwsem_write(policy->cpu);
713 cpufreq_cpu_put(policy);
718 static void cpufreq_sysfs_release(struct kobject *kobj)
720 struct cpufreq_policy *policy = to_policy(kobj);
721 dprintk("last reference is dropped\n");
722 complete(&policy->kobj_unregister);
725 static struct sysfs_ops sysfs_ops = {
730 static struct kobj_type ktype_cpufreq = {
731 .sysfs_ops = &sysfs_ops,
732 .default_attrs = default_attrs,
733 .release = cpufreq_sysfs_release,
738 * cpufreq_add_dev - add a CPU device
740 * Adds the cpufreq interface for a CPU device.
742 static int cpufreq_add_dev(struct sys_device *sys_dev)
744 unsigned int cpu = sys_dev->id;
746 struct cpufreq_policy new_policy;
747 struct cpufreq_policy *policy;
748 struct freq_attr **drv_attr;
749 struct sys_device *cpu_sys_dev;
753 struct cpufreq_policy *managed_policy;
756 if (cpu_is_offline(cpu))
759 cpufreq_debug_disable_ratelimit();
760 dprintk("adding CPU %u\n", cpu);
763 /* check whether a different CPU already registered this
764 * CPU because it is in the same boat. */
765 policy = cpufreq_cpu_get(cpu);
766 if (unlikely(policy)) {
767 cpufreq_cpu_put(policy);
768 cpufreq_debug_enable_ratelimit();
773 if (!try_module_get(cpufreq_driver->owner)) {
778 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
785 policy->cpus = cpumask_of_cpu(cpu);
787 /* Initially set CPU itself as the policy_cpu */
788 per_cpu(policy_cpu, cpu) = cpu;
789 lock_policy_rwsem_write(cpu);
791 init_completion(&policy->kobj_unregister);
792 INIT_WORK(&policy->update, handle_update);
794 /* Set governor before ->init, so that driver could check it */
795 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
796 /* call driver. From then on the cpufreq must be able
797 * to accept all calls to ->verify and ->setpolicy for this CPU
799 ret = cpufreq_driver->init(policy);
801 dprintk("initialization failed\n");
804 policy->user_policy.min = policy->cpuinfo.min_freq;
805 policy->user_policy.max = policy->cpuinfo.max_freq;
809 #ifdef CONFIG_HOTPLUG_CPU
810 if (cpufreq_cpu_governor[cpu]){
811 policy->governor = cpufreq_cpu_governor[cpu];
812 dprintk("Restoring governor %s for cpu %d\n",
813 policy->governor->name, cpu);
817 for_each_cpu_mask(j, policy->cpus) {
821 /* check for existing affected CPUs. They may not be aware
822 * of it due to CPU Hotplug.
824 managed_policy = cpufreq_cpu_get(j); // FIXME: Where is this released? What about error paths?
825 if (unlikely(managed_policy)) {
827 /* Set proper policy_cpu */
828 unlock_policy_rwsem_write(cpu);
829 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
831 if (lock_policy_rwsem_write(cpu) < 0)
832 goto err_out_driver_exit;
834 spin_lock_irqsave(&cpufreq_driver_lock, flags);
835 managed_policy->cpus = policy->cpus;
836 cpufreq_cpu_data[cpu] = managed_policy;
837 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
839 dprintk("CPU already managed, adding link\n");
840 ret = sysfs_create_link(&sys_dev->kobj,
841 &managed_policy->kobj,
844 goto err_out_driver_exit;
846 cpufreq_debug_enable_ratelimit();
848 goto err_out_driver_exit; /* call driver->exit() */
852 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
854 /* prepare interface data */
855 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
858 goto err_out_driver_exit;
860 /* set up files for this cpu device */
861 drv_attr = cpufreq_driver->attr;
862 while ((drv_attr) && (*drv_attr)) {
863 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
865 goto err_out_driver_exit;
868 if (cpufreq_driver->get) {
869 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
871 goto err_out_driver_exit;
873 if (cpufreq_driver->target) {
874 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
876 goto err_out_driver_exit;
879 spin_lock_irqsave(&cpufreq_driver_lock, flags);
880 for_each_cpu_mask(j, policy->cpus) {
881 cpufreq_cpu_data[j] = policy;
882 per_cpu(policy_cpu, j) = policy->cpu;
884 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
886 /* symlink affected CPUs */
887 for_each_cpu_mask(j, policy->cpus) {
893 dprintk("CPU %u already managed, adding link\n", j);
894 cpufreq_cpu_get(cpu);
895 cpu_sys_dev = get_cpu_sysdev(j);
896 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
899 goto err_out_unregister;
902 policy->governor = NULL; /* to assure that the starting sequence is
903 * run in cpufreq_set_policy */
905 /* set default policy */
906 ret = __cpufreq_set_policy(policy, &new_policy);
907 policy->user_policy.policy = policy->policy;
908 policy->user_policy.governor = policy->governor;
910 unlock_policy_rwsem_write(cpu);
913 dprintk("setting policy failed\n");
914 goto err_out_unregister;
917 kobject_uevent(&policy->kobj, KOBJ_ADD);
918 module_put(cpufreq_driver->owner);
919 dprintk("initialization complete\n");
920 cpufreq_debug_enable_ratelimit();
926 spin_lock_irqsave(&cpufreq_driver_lock, flags);
927 for_each_cpu_mask(j, policy->cpus)
928 cpufreq_cpu_data[j] = NULL;
929 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
931 kobject_put(&policy->kobj);
932 wait_for_completion(&policy->kobj_unregister);
935 if (cpufreq_driver->exit)
936 cpufreq_driver->exit(policy);
939 unlock_policy_rwsem_write(cpu);
943 module_put(cpufreq_driver->owner);
945 cpufreq_debug_enable_ratelimit();
951 * __cpufreq_remove_dev - remove a CPU device
953 * Removes the cpufreq interface for a CPU device.
954 * Caller should already have policy_rwsem in write mode for this CPU.
955 * This routine frees the rwsem before returning.
957 static int __cpufreq_remove_dev(struct sys_device *sys_dev)
959 unsigned int cpu = sys_dev->id;
961 struct cpufreq_policy *data;
963 struct sys_device *cpu_sys_dev;
967 cpufreq_debug_disable_ratelimit();
968 dprintk("unregistering CPU %u\n", cpu);
970 spin_lock_irqsave(&cpufreq_driver_lock, flags);
971 data = cpufreq_cpu_data[cpu];
974 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
975 cpufreq_debug_enable_ratelimit();
976 unlock_policy_rwsem_write(cpu);
979 cpufreq_cpu_data[cpu] = NULL;
983 /* if this isn't the CPU which is the parent of the kobj, we
984 * only need to unlink, put and exit
986 if (unlikely(cpu != data->cpu)) {
987 dprintk("removing link\n");
988 cpu_clear(cpu, data->cpus);
989 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
990 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
991 cpufreq_cpu_put(data);
992 cpufreq_debug_enable_ratelimit();
993 unlock_policy_rwsem_write(cpu);
1000 #ifdef CONFIG_HOTPLUG_CPU
1001 cpufreq_cpu_governor[cpu] = data->governor;
1004 /* if we have other CPUs still registered, we need to unlink them,
1005 * or else wait_for_completion below will lock up. Clean the
1006 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
1009 if (unlikely(cpus_weight(data->cpus) > 1)) {
1010 for_each_cpu_mask(j, data->cpus) {
1013 cpufreq_cpu_data[j] = NULL;
1017 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1019 if (unlikely(cpus_weight(data->cpus) > 1)) {
1020 for_each_cpu_mask(j, data->cpus) {
1023 dprintk("removing link for cpu %u\n", j);
1024 #ifdef CONFIG_HOTPLUG_CPU
1025 cpufreq_cpu_governor[j] = data->governor;
1027 cpu_sys_dev = get_cpu_sysdev(j);
1028 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1029 cpufreq_cpu_put(data);
1033 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1036 if (cpufreq_driver->target)
1037 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1039 unlock_policy_rwsem_write(cpu);
1041 kobject_put(&data->kobj);
1043 /* we need to make sure that the underlying kobj is actually
1044 * not referenced anymore by anybody before we proceed with
1047 dprintk("waiting for dropping of refcount\n");
1048 wait_for_completion(&data->kobj_unregister);
1049 dprintk("wait complete\n");
1051 if (cpufreq_driver->exit)
1052 cpufreq_driver->exit(data);
1056 cpufreq_debug_enable_ratelimit();
1061 static int cpufreq_remove_dev(struct sys_device *sys_dev)
1063 unsigned int cpu = sys_dev->id;
1066 if (cpu_is_offline(cpu))
1069 if (unlikely(lock_policy_rwsem_write(cpu)))
1072 retval = __cpufreq_remove_dev(sys_dev);
1077 static void handle_update(struct work_struct *work)
1079 struct cpufreq_policy *policy =
1080 container_of(work, struct cpufreq_policy, update);
1081 unsigned int cpu = policy->cpu;
1082 dprintk("handle_update for cpu %u called\n", cpu);
1083 cpufreq_update_policy(cpu);
1087 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1089 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1090 * @new_freq: CPU frequency the CPU actually runs at
1092 * We adjust to current frequency first, and need to clean up later. So either call
1093 * to cpufreq_update_policy() or schedule handle_update()).
1095 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1096 unsigned int new_freq)
1098 struct cpufreq_freqs freqs;
1100 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1101 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1104 freqs.old = old_freq;
1105 freqs.new = new_freq;
1106 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1107 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1112 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1115 * This is the last known freq, without actually getting it from the driver.
1116 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1118 unsigned int cpufreq_quick_get(unsigned int cpu)
1120 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1121 unsigned int ret_freq = 0;
1124 ret_freq = policy->cur;
1125 cpufreq_cpu_put(policy);
1130 EXPORT_SYMBOL(cpufreq_quick_get);
1133 static unsigned int __cpufreq_get(unsigned int cpu)
1135 struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1136 unsigned int ret_freq = 0;
1138 if (!cpufreq_driver->get)
1141 ret_freq = cpufreq_driver->get(cpu);
1143 if (ret_freq && policy->cur &&
1144 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1145 /* verify no discrepancy between actual and
1146 saved value exists */
1147 if (unlikely(ret_freq != policy->cur)) {
1148 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1149 schedule_work(&policy->update);
1157 * cpufreq_get - get the current CPU frequency (in kHz)
1160 * Get the CPU current (static) CPU frequency
1162 unsigned int cpufreq_get(unsigned int cpu)
1164 unsigned int ret_freq = 0;
1165 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1170 if (unlikely(lock_policy_rwsem_read(cpu)))
1173 ret_freq = __cpufreq_get(cpu);
1175 unlock_policy_rwsem_read(cpu);
1178 cpufreq_cpu_put(policy);
1182 EXPORT_SYMBOL(cpufreq_get);
1186 * cpufreq_suspend - let the low level driver prepare for suspend
1189 static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
1191 int cpu = sysdev->id;
1193 unsigned int cur_freq = 0;
1194 struct cpufreq_policy *cpu_policy;
1196 dprintk("suspending cpu %u\n", cpu);
1198 if (!cpu_online(cpu))
1201 /* we may be lax here as interrupts are off. Nonetheless
1202 * we need to grab the correct cpu policy, as to check
1203 * whether we really run on this CPU.
1206 cpu_policy = cpufreq_cpu_get(cpu);
1210 /* only handle each CPU group once */
1211 if (unlikely(cpu_policy->cpu != cpu))
1214 if (cpufreq_driver->suspend) {
1215 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1217 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1218 "step on CPU %u\n", cpu_policy->cpu);
1223 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1226 if (cpufreq_driver->get)
1227 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1229 if (!cur_freq || !cpu_policy->cur) {
1230 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1231 "frequency is what timing core thinks it is.\n");
1235 if (unlikely(cur_freq != cpu_policy->cur)) {
1236 struct cpufreq_freqs freqs;
1238 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1239 dprintk("Warning: CPU frequency is %u, "
1240 "cpufreq assumed %u kHz.\n",
1241 cur_freq, cpu_policy->cur);
1244 freqs.old = cpu_policy->cur;
1245 freqs.new = cur_freq;
1247 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1248 CPUFREQ_SUSPENDCHANGE, &freqs);
1249 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1251 cpu_policy->cur = cur_freq;
1255 cpufreq_cpu_put(cpu_policy);
1260 * cpufreq_resume - restore proper CPU frequency handling after resume
1262 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1263 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1264 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1267 static int cpufreq_resume(struct sys_device *sysdev)
1269 int cpu = sysdev->id;
1271 struct cpufreq_policy *cpu_policy;
1273 dprintk("resuming cpu %u\n", cpu);
1275 if (!cpu_online(cpu))
1278 /* we may be lax here as interrupts are off. Nonetheless
1279 * we need to grab the correct cpu policy, as to check
1280 * whether we really run on this CPU.
1283 cpu_policy = cpufreq_cpu_get(cpu);
1287 /* only handle each CPU group once */
1288 if (unlikely(cpu_policy->cpu != cpu))
1291 if (cpufreq_driver->resume) {
1292 ret = cpufreq_driver->resume(cpu_policy);
1294 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1295 "step on CPU %u\n", cpu_policy->cpu);
1300 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1301 unsigned int cur_freq = 0;
1303 if (cpufreq_driver->get)
1304 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1306 if (!cur_freq || !cpu_policy->cur) {
1307 printk(KERN_ERR "cpufreq: resume failed to assert "
1308 "current frequency is what timing core "
1313 if (unlikely(cur_freq != cpu_policy->cur)) {
1314 struct cpufreq_freqs freqs;
1316 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1317 dprintk("Warning: CPU frequency "
1318 "is %u, cpufreq assumed %u kHz.\n",
1319 cur_freq, cpu_policy->cur);
1322 freqs.old = cpu_policy->cur;
1323 freqs.new = cur_freq;
1325 srcu_notifier_call_chain(
1326 &cpufreq_transition_notifier_list,
1327 CPUFREQ_RESUMECHANGE, &freqs);
1328 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1330 cpu_policy->cur = cur_freq;
1335 schedule_work(&cpu_policy->update);
1337 cpufreq_cpu_put(cpu_policy);
1341 static struct sysdev_driver cpufreq_sysdev_driver = {
1342 .add = cpufreq_add_dev,
1343 .remove = cpufreq_remove_dev,
1344 .suspend = cpufreq_suspend,
1345 .resume = cpufreq_resume,
1349 /*********************************************************************
1350 * NOTIFIER LISTS INTERFACE *
1351 *********************************************************************/
1354 * cpufreq_register_notifier - register a driver with cpufreq
1355 * @nb: notifier function to register
1356 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1358 * Add a driver to one of two lists: either a list of drivers that
1359 * are notified about clock rate changes (once before and once after
1360 * the transition), or a list of drivers that are notified about
1361 * changes in cpufreq policy.
1363 * This function may sleep, and has the same return conditions as
1364 * blocking_notifier_chain_register.
1366 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1371 case CPUFREQ_TRANSITION_NOTIFIER:
1372 ret = srcu_notifier_chain_register(
1373 &cpufreq_transition_notifier_list, nb);
1375 case CPUFREQ_POLICY_NOTIFIER:
1376 ret = blocking_notifier_chain_register(
1377 &cpufreq_policy_notifier_list, nb);
1385 EXPORT_SYMBOL(cpufreq_register_notifier);
1389 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1390 * @nb: notifier block to be unregistered
1391 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1393 * Remove a driver from the CPU frequency notifier list.
1395 * This function may sleep, and has the same return conditions as
1396 * blocking_notifier_chain_unregister.
1398 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1403 case CPUFREQ_TRANSITION_NOTIFIER:
1404 ret = srcu_notifier_chain_unregister(
1405 &cpufreq_transition_notifier_list, nb);
1407 case CPUFREQ_POLICY_NOTIFIER:
1408 ret = blocking_notifier_chain_unregister(
1409 &cpufreq_policy_notifier_list, nb);
1417 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1420 /*********************************************************************
1422 *********************************************************************/
1425 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1426 unsigned int target_freq,
1427 unsigned int relation)
1429 int retval = -EINVAL;
1431 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1432 target_freq, relation);
1433 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1434 retval = cpufreq_driver->target(policy, target_freq, relation);
1438 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1440 int cpufreq_driver_target(struct cpufreq_policy *policy,
1441 unsigned int target_freq,
1442 unsigned int relation)
1446 policy = cpufreq_cpu_get(policy->cpu);
1450 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1453 ret = __cpufreq_driver_target(policy, target_freq, relation);
1455 unlock_policy_rwsem_write(policy->cpu);
1457 cpufreq_cpu_put(policy);
1460 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1462 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1466 policy = cpufreq_cpu_get(policy->cpu);
1470 if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1471 ret = cpufreq_driver->getavg(policy->cpu);
1473 cpufreq_cpu_put(policy);
1476 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1479 * when "event" is CPUFREQ_GOV_LIMITS
1482 static int __cpufreq_governor(struct cpufreq_policy *policy,
1487 /* Only must be defined when default governor is known to have latency
1488 restrictions, like e.g. conservative or ondemand.
1489 That this is the case is already ensured in Kconfig
1491 #ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1492 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1494 struct cpufreq_governor *gov = NULL;
1497 if (policy->governor->max_transition_latency &&
1498 policy->cpuinfo.transition_latency >
1499 policy->governor->max_transition_latency) {
1503 printk(KERN_WARNING "%s governor failed, too long"
1504 " transition latency of HW, fallback"
1505 " to %s governor\n",
1506 policy->governor->name,
1508 policy->governor = gov;
1512 if (!try_module_get(policy->governor->owner))
1515 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1516 policy->cpu, event);
1517 ret = policy->governor->governor(policy, event);
1519 /* we keep one module reference alive for
1520 each CPU governed by this CPU */
1521 if ((event != CPUFREQ_GOV_START) || ret)
1522 module_put(policy->governor->owner);
1523 if ((event == CPUFREQ_GOV_STOP) && !ret)
1524 module_put(policy->governor->owner);
1530 int cpufreq_register_governor(struct cpufreq_governor *governor)
1537 mutex_lock(&cpufreq_governor_mutex);
1540 if (__find_governor(governor->name) == NULL) {
1542 list_add(&governor->governor_list, &cpufreq_governor_list);
1545 mutex_unlock(&cpufreq_governor_mutex);
1548 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1551 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1556 mutex_lock(&cpufreq_governor_mutex);
1557 list_del(&governor->governor_list);
1558 mutex_unlock(&cpufreq_governor_mutex);
1561 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1565 /*********************************************************************
1566 * POLICY INTERFACE *
1567 *********************************************************************/
1570 * cpufreq_get_policy - get the current cpufreq_policy
1571 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1573 * Reads the current cpufreq policy.
1575 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1577 struct cpufreq_policy *cpu_policy;
1581 cpu_policy = cpufreq_cpu_get(cpu);
1585 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1587 cpufreq_cpu_put(cpu_policy);
1590 EXPORT_SYMBOL(cpufreq_get_policy);
1594 * data : current policy.
1595 * policy : policy to be set.
1597 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1598 struct cpufreq_policy *policy)
1602 cpufreq_debug_disable_ratelimit();
1603 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1604 policy->min, policy->max);
1606 memcpy(&policy->cpuinfo, &data->cpuinfo,
1607 sizeof(struct cpufreq_cpuinfo));
1609 if (policy->min > data->max || policy->max < data->min) {
1614 /* verify the cpu speed can be set within this limit */
1615 ret = cpufreq_driver->verify(policy);
1619 /* adjust if necessary - all reasons */
1620 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1621 CPUFREQ_ADJUST, policy);
1623 /* adjust if necessary - hardware incompatibility*/
1624 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1625 CPUFREQ_INCOMPATIBLE, policy);
1627 /* verify the cpu speed can be set within this limit,
1628 which might be different to the first one */
1629 ret = cpufreq_driver->verify(policy);
1633 /* notification of the new policy */
1634 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1635 CPUFREQ_NOTIFY, policy);
1637 data->min = policy->min;
1638 data->max = policy->max;
1640 dprintk("new min and max freqs are %u - %u kHz\n",
1641 data->min, data->max);
1643 if (cpufreq_driver->setpolicy) {
1644 data->policy = policy->policy;
1645 dprintk("setting range\n");
1646 ret = cpufreq_driver->setpolicy(policy);
1648 if (policy->governor != data->governor) {
1649 /* save old, working values */
1650 struct cpufreq_governor *old_gov = data->governor;
1652 dprintk("governor switch\n");
1654 /* end old governor */
1656 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1658 /* start new governor */
1659 data->governor = policy->governor;
1660 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1661 /* new governor failed, so re-start old one */
1662 dprintk("starting governor %s failed\n",
1663 data->governor->name);
1665 data->governor = old_gov;
1666 __cpufreq_governor(data,
1672 /* might be a policy change, too, so fall through */
1674 dprintk("governor: change or update limits\n");
1675 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1679 cpufreq_debug_enable_ratelimit();
1684 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1685 * @cpu: CPU which shall be re-evaluated
1687 * Usefull for policy notifiers which have different necessities
1688 * at different times.
1690 int cpufreq_update_policy(unsigned int cpu)
1692 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1693 struct cpufreq_policy policy;
1699 if (unlikely(lock_policy_rwsem_write(cpu)))
1702 dprintk("updating policy for CPU %u\n", cpu);
1703 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1704 policy.min = data->user_policy.min;
1705 policy.max = data->user_policy.max;
1706 policy.policy = data->user_policy.policy;
1707 policy.governor = data->user_policy.governor;
1709 /* BIOS might change freq behind our back
1710 -> ask driver for current freq and notify governors about a change */
1711 if (cpufreq_driver->get) {
1712 policy.cur = cpufreq_driver->get(cpu);
1714 dprintk("Driver did not initialize current freq");
1715 data->cur = policy.cur;
1717 if (data->cur != policy.cur)
1718 cpufreq_out_of_sync(cpu, data->cur,
1723 ret = __cpufreq_set_policy(data, &policy);
1725 unlock_policy_rwsem_write(cpu);
1727 cpufreq_cpu_put(data);
1730 EXPORT_SYMBOL(cpufreq_update_policy);
1732 static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1733 unsigned long action, void *hcpu)
1735 unsigned int cpu = (unsigned long)hcpu;
1736 struct sys_device *sys_dev;
1738 sys_dev = get_cpu_sysdev(cpu);
1742 case CPU_ONLINE_FROZEN:
1743 cpufreq_add_dev(sys_dev);
1745 case CPU_DOWN_PREPARE:
1746 case CPU_DOWN_PREPARE_FROZEN:
1747 if (unlikely(lock_policy_rwsem_write(cpu)))
1750 __cpufreq_remove_dev(sys_dev);
1752 case CPU_DOWN_FAILED:
1753 case CPU_DOWN_FAILED_FROZEN:
1754 cpufreq_add_dev(sys_dev);
1761 static struct notifier_block __refdata cpufreq_cpu_notifier =
1763 .notifier_call = cpufreq_cpu_callback,
1766 /*********************************************************************
1767 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1768 *********************************************************************/
1771 * cpufreq_register_driver - register a CPU Frequency driver
1772 * @driver_data: A struct cpufreq_driver containing the values#
1773 * submitted by the CPU Frequency driver.
1775 * Registers a CPU Frequency driver to this core code. This code
1776 * returns zero on success, -EBUSY when another driver got here first
1777 * (and isn't unregistered in the meantime).
1780 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1782 unsigned long flags;
1785 if (!driver_data || !driver_data->verify || !driver_data->init ||
1786 ((!driver_data->setpolicy) && (!driver_data->target)))
1789 dprintk("trying to register driver %s\n", driver_data->name);
1791 if (driver_data->setpolicy)
1792 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1794 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1795 if (cpufreq_driver) {
1796 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1799 cpufreq_driver = driver_data;
1800 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1802 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1804 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1808 /* check for at least one working CPU */
1809 for (i=0; i<NR_CPUS; i++)
1810 if (cpufreq_cpu_data[i])
1813 /* if all ->init() calls failed, unregister */
1815 dprintk("no CPU initialized for driver %s\n",
1817 sysdev_driver_unregister(&cpu_sysdev_class,
1818 &cpufreq_sysdev_driver);
1820 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1821 cpufreq_driver = NULL;
1822 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1827 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1828 dprintk("driver %s up and running\n", driver_data->name);
1829 cpufreq_debug_enable_ratelimit();
1834 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1838 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1840 * Unregister the current CPUFreq driver. Only call this if you have
1841 * the right to do so, i.e. if you have succeeded in initialising before!
1842 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1843 * currently not initialised.
1845 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1847 unsigned long flags;
1849 cpufreq_debug_disable_ratelimit();
1851 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1852 cpufreq_debug_enable_ratelimit();
1856 dprintk("unregistering driver %s\n", driver->name);
1858 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1859 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1861 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1862 cpufreq_driver = NULL;
1863 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1867 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1869 static int __init cpufreq_core_init(void)
1873 for_each_possible_cpu(cpu) {
1874 per_cpu(policy_cpu, cpu) = -1;
1875 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1880 core_initcall(cpufreq_core_init);