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 static DEFINE_SPINLOCK(cpufreq_driver_lock);
45 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
46 * all cpufreq/hotplug/workqueue/etc related lock issues.
48 * The rules for this semaphore:
49 * - Any routine that wants to read from the policy structure will
50 * do a down_read on this semaphore.
51 * - Any routine that will write to the policy structure and/or may take away
52 * the policy altogether (eg. CPU hotplug), will hold this lock in write
53 * mode before doing so.
56 * - All holders of the lock should check to make sure that the CPU they
57 * are concerned with are online after they get the lock.
58 * - Governor routines that can be called in cpufreq hotplug path should not
59 * take this sem as top level hotplug notifier handler takes this.
61 static DEFINE_PER_CPU(int, policy_cpu);
62 static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
64 #define lock_policy_rwsem(mode, cpu) \
65 int lock_policy_rwsem_##mode \
68 int policy_cpu = per_cpu(policy_cpu, cpu); \
69 BUG_ON(policy_cpu == -1); \
70 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
71 if (unlikely(!cpu_online(cpu))) { \
72 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
79 lock_policy_rwsem(read, cpu);
80 EXPORT_SYMBOL_GPL(lock_policy_rwsem_read);
82 lock_policy_rwsem(write, cpu);
83 EXPORT_SYMBOL_GPL(lock_policy_rwsem_write);
85 void unlock_policy_rwsem_read(int cpu)
87 int policy_cpu = per_cpu(policy_cpu, cpu);
88 BUG_ON(policy_cpu == -1);
89 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
91 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_read);
93 void unlock_policy_rwsem_write(int cpu)
95 int policy_cpu = per_cpu(policy_cpu, cpu);
96 BUG_ON(policy_cpu == -1);
97 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
99 EXPORT_SYMBOL_GPL(unlock_policy_rwsem_write);
102 /* internal prototypes */
103 static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
104 static unsigned int __cpufreq_get(unsigned int cpu);
105 static void handle_update(struct work_struct *work);
108 * Two notifier lists: the "policy" list is involved in the
109 * validation process for a new CPU frequency policy; the
110 * "transition" list for kernel code that needs to handle
111 * changes to devices when the CPU clock speed changes.
112 * The mutex locks both lists.
114 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
115 static struct srcu_notifier_head cpufreq_transition_notifier_list;
117 static int __init init_cpufreq_transition_notifier_list(void)
119 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
122 pure_initcall(init_cpufreq_transition_notifier_list);
124 static LIST_HEAD(cpufreq_governor_list);
125 static DEFINE_MUTEX (cpufreq_governor_mutex);
127 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
129 struct cpufreq_policy *data;
135 /* get the cpufreq driver */
136 spin_lock_irqsave(&cpufreq_driver_lock, flags);
141 if (!try_module_get(cpufreq_driver->owner))
146 data = cpufreq_cpu_data[cpu];
149 goto err_out_put_module;
151 if (!kobject_get(&data->kobj))
152 goto err_out_put_module;
154 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
158 module_put(cpufreq_driver->owner);
160 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
164 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
167 void cpufreq_cpu_put(struct cpufreq_policy *data)
169 kobject_put(&data->kobj);
170 module_put(cpufreq_driver->owner);
172 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
175 /*********************************************************************
176 * UNIFIED DEBUG HELPERS *
177 *********************************************************************/
178 #ifdef CONFIG_CPU_FREQ_DEBUG
180 /* what part(s) of the CPUfreq subsystem are debugged? */
181 static unsigned int debug;
183 /* is the debug output ratelimit'ed using printk_ratelimit? User can
184 * set or modify this value.
186 static unsigned int debug_ratelimit = 1;
188 /* is the printk_ratelimit'ing enabled? It's enabled after a successful
189 * loading of a cpufreq driver, temporarily disabled when a new policy
190 * is set, and disabled upon cpufreq driver removal
192 static unsigned int disable_ratelimit = 1;
193 static DEFINE_SPINLOCK(disable_ratelimit_lock);
195 static void cpufreq_debug_enable_ratelimit(void)
199 spin_lock_irqsave(&disable_ratelimit_lock, flags);
200 if (disable_ratelimit)
202 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
205 static void cpufreq_debug_disable_ratelimit(void)
209 spin_lock_irqsave(&disable_ratelimit_lock, flags);
211 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
214 void cpufreq_debug_printk(unsigned int type, const char *prefix,
215 const char *fmt, ...)
224 spin_lock_irqsave(&disable_ratelimit_lock, flags);
225 if (!disable_ratelimit && debug_ratelimit
226 && !printk_ratelimit()) {
227 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
230 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
232 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
235 len += vsnprintf(&s[len], (256 - len), fmt, args);
243 EXPORT_SYMBOL(cpufreq_debug_printk);
246 module_param(debug, uint, 0644);
247 MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
248 " 2 to debug drivers, and 4 to debug governors.");
250 module_param(debug_ratelimit, uint, 0644);
251 MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
252 " set to 0 to disable ratelimiting.");
254 #else /* !CONFIG_CPU_FREQ_DEBUG */
256 static inline void cpufreq_debug_enable_ratelimit(void) { return; }
257 static inline void cpufreq_debug_disable_ratelimit(void) { return; }
259 #endif /* CONFIG_CPU_FREQ_DEBUG */
262 /*********************************************************************
263 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
264 *********************************************************************/
267 * adjust_jiffies - adjust the system "loops_per_jiffy"
269 * This function alters the system "loops_per_jiffy" for the clock
270 * speed change. Note that loops_per_jiffy cannot be updated on SMP
271 * systems as each CPU might be scaled differently. So, use the arch
272 * per-CPU loops_per_jiffy value wherever possible.
275 static unsigned long l_p_j_ref;
276 static unsigned int l_p_j_ref_freq;
278 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
280 if (ci->flags & CPUFREQ_CONST_LOOPS)
283 if (!l_p_j_ref_freq) {
284 l_p_j_ref = loops_per_jiffy;
285 l_p_j_ref_freq = ci->old;
286 dprintk("saving %lu as reference value for loops_per_jiffy;"
287 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
289 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
290 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
291 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
292 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
294 dprintk("scaling loops_per_jiffy to %lu"
295 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
299 static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
307 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
308 * on frequency transition.
310 * This function calls the transition notifiers and the "adjust_jiffies"
311 * function. It is called twice on all CPU frequency changes that have
314 void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
316 struct cpufreq_policy *policy;
318 BUG_ON(irqs_disabled());
320 freqs->flags = cpufreq_driver->flags;
321 dprintk("notification %u of frequency transition to %u kHz\n",
324 policy = cpufreq_cpu_data[freqs->cpu];
327 case CPUFREQ_PRECHANGE:
328 /* detect if the driver reported a value as "old frequency"
329 * which is not equal to what the cpufreq core thinks is
332 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
333 if ((policy) && (policy->cpu == freqs->cpu) &&
334 (policy->cur) && (policy->cur != freqs->old)) {
335 dprintk("Warning: CPU frequency is"
336 " %u, cpufreq assumed %u kHz.\n",
337 freqs->old, policy->cur);
338 freqs->old = policy->cur;
341 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
342 CPUFREQ_PRECHANGE, freqs);
343 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
346 case CPUFREQ_POSTCHANGE:
347 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
348 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
349 CPUFREQ_POSTCHANGE, freqs);
350 if (likely(policy) && likely(policy->cpu == freqs->cpu))
351 policy->cur = freqs->new;
355 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
359 /*********************************************************************
361 *********************************************************************/
363 static struct cpufreq_governor *__find_governor(const char *str_governor)
365 struct cpufreq_governor *t;
367 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
368 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN))
375 * cpufreq_parse_governor - parse a governor string
377 static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
378 struct cpufreq_governor **governor)
385 if (cpufreq_driver->setpolicy) {
386 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
387 *policy = CPUFREQ_POLICY_PERFORMANCE;
389 } else if (!strnicmp(str_governor, "powersave",
391 *policy = CPUFREQ_POLICY_POWERSAVE;
394 } else if (cpufreq_driver->target) {
395 struct cpufreq_governor *t;
397 mutex_lock(&cpufreq_governor_mutex);
399 t = __find_governor(str_governor);
402 char *name = kasprintf(GFP_KERNEL, "cpufreq_%s",
408 mutex_unlock(&cpufreq_governor_mutex);
409 ret = request_module(name);
410 mutex_lock(&cpufreq_governor_mutex);
413 t = __find_governor(str_governor);
424 mutex_unlock(&cpufreq_governor_mutex);
431 /* drivers/base/cpu.c */
432 extern struct sysdev_class cpu_sysdev_class;
436 * cpufreq_per_cpu_attr_read() / show_##file_name() -
437 * print out cpufreq information
439 * Write out information from cpufreq_driver->policy[cpu]; object must be
443 #define show_one(file_name, object) \
444 static ssize_t show_##file_name \
445 (struct cpufreq_policy * policy, char *buf) \
447 return sprintf (buf, "%u\n", policy->object); \
450 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
451 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
452 show_one(scaling_min_freq, min);
453 show_one(scaling_max_freq, max);
454 show_one(scaling_cur_freq, cur);
456 static int __cpufreq_set_policy(struct cpufreq_policy *data,
457 struct cpufreq_policy *policy);
460 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
462 #define store_one(file_name, object) \
463 static ssize_t store_##file_name \
464 (struct cpufreq_policy * policy, const char *buf, size_t count) \
466 unsigned int ret = -EINVAL; \
467 struct cpufreq_policy new_policy; \
469 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
473 ret = sscanf (buf, "%u", &new_policy.object); \
477 ret = __cpufreq_set_policy(policy, &new_policy); \
478 policy->user_policy.object = policy->object; \
480 return ret ? ret : count; \
483 store_one(scaling_min_freq,min);
484 store_one(scaling_max_freq,max);
487 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
489 static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy,
492 unsigned int cur_freq = __cpufreq_get(policy->cpu);
494 return sprintf(buf, "<unknown>");
495 return sprintf(buf, "%u\n", cur_freq);
500 * show_scaling_governor - show the current policy for the specified CPU
502 static ssize_t show_scaling_governor (struct cpufreq_policy * policy,
505 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
506 return sprintf(buf, "powersave\n");
507 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
508 return sprintf(buf, "performance\n");
509 else if (policy->governor)
510 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
516 * store_scaling_governor - store policy for the specified CPU
518 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
519 const char *buf, size_t count)
521 unsigned int ret = -EINVAL;
522 char str_governor[16];
523 struct cpufreq_policy new_policy;
525 ret = cpufreq_get_policy(&new_policy, policy->cpu);
529 ret = sscanf (buf, "%15s", str_governor);
533 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
534 &new_policy.governor))
537 /* Do not use cpufreq_set_policy here or the user_policy.max
538 will be wrongly overridden */
539 ret = __cpufreq_set_policy(policy, &new_policy);
541 policy->user_policy.policy = policy->policy;
542 policy->user_policy.governor = policy->governor;
551 * show_scaling_driver - show the cpufreq driver currently loaded
553 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
555 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
559 * show_scaling_available_governors - show the available CPUfreq governors
561 static ssize_t show_scaling_available_governors (struct cpufreq_policy *policy,
565 struct cpufreq_governor *t;
567 if (!cpufreq_driver->target) {
568 i += sprintf(buf, "performance powersave");
572 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
573 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
575 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
578 i += sprintf(&buf[i], "\n");
582 * show_affected_cpus - show the CPUs affected by each transition
584 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
589 for_each_cpu_mask(cpu, policy->cpus) {
591 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
592 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
593 if (i >= (PAGE_SIZE - 5))
596 i += sprintf(&buf[i], "\n");
601 #define define_one_ro(_name) \
602 static struct freq_attr _name = \
603 __ATTR(_name, 0444, show_##_name, NULL)
605 #define define_one_ro0400(_name) \
606 static struct freq_attr _name = \
607 __ATTR(_name, 0400, show_##_name, NULL)
609 #define define_one_rw(_name) \
610 static struct freq_attr _name = \
611 __ATTR(_name, 0644, show_##_name, store_##_name)
613 define_one_ro0400(cpuinfo_cur_freq);
614 define_one_ro(cpuinfo_min_freq);
615 define_one_ro(cpuinfo_max_freq);
616 define_one_ro(scaling_available_governors);
617 define_one_ro(scaling_driver);
618 define_one_ro(scaling_cur_freq);
619 define_one_ro(affected_cpus);
620 define_one_rw(scaling_min_freq);
621 define_one_rw(scaling_max_freq);
622 define_one_rw(scaling_governor);
624 static struct attribute * default_attrs[] = {
625 &cpuinfo_min_freq.attr,
626 &cpuinfo_max_freq.attr,
627 &scaling_min_freq.attr,
628 &scaling_max_freq.attr,
630 &scaling_governor.attr,
631 &scaling_driver.attr,
632 &scaling_available_governors.attr,
636 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
637 #define to_attr(a) container_of(a,struct freq_attr,attr)
639 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
641 struct cpufreq_policy * policy = to_policy(kobj);
642 struct freq_attr * fattr = to_attr(attr);
644 policy = cpufreq_cpu_get(policy->cpu);
648 if (lock_policy_rwsem_read(policy->cpu) < 0)
652 ret = fattr->show(policy, buf);
656 unlock_policy_rwsem_read(policy->cpu);
658 cpufreq_cpu_put(policy);
662 static ssize_t store(struct kobject * kobj, struct attribute * attr,
663 const char * buf, size_t count)
665 struct cpufreq_policy * policy = to_policy(kobj);
666 struct freq_attr * fattr = to_attr(attr);
668 policy = cpufreq_cpu_get(policy->cpu);
672 if (lock_policy_rwsem_write(policy->cpu) < 0)
676 ret = fattr->store(policy, buf, count);
680 unlock_policy_rwsem_write(policy->cpu);
682 cpufreq_cpu_put(policy);
686 static void cpufreq_sysfs_release(struct kobject * kobj)
688 struct cpufreq_policy * policy = to_policy(kobj);
689 dprintk("last reference is dropped\n");
690 complete(&policy->kobj_unregister);
693 static struct sysfs_ops sysfs_ops = {
698 static struct kobj_type ktype_cpufreq = {
699 .sysfs_ops = &sysfs_ops,
700 .default_attrs = default_attrs,
701 .release = cpufreq_sysfs_release,
706 * cpufreq_add_dev - add a CPU device
708 * Adds the cpufreq interface for a CPU device.
710 static int cpufreq_add_dev (struct sys_device * sys_dev)
712 unsigned int cpu = sys_dev->id;
714 struct cpufreq_policy new_policy;
715 struct cpufreq_policy *policy;
716 struct freq_attr **drv_attr;
717 struct sys_device *cpu_sys_dev;
721 struct cpufreq_policy *managed_policy;
724 if (cpu_is_offline(cpu))
727 cpufreq_debug_disable_ratelimit();
728 dprintk("adding CPU %u\n", cpu);
731 /* check whether a different CPU already registered this
732 * CPU because it is in the same boat. */
733 policy = cpufreq_cpu_get(cpu);
734 if (unlikely(policy)) {
735 cpufreq_cpu_put(policy);
736 cpufreq_debug_enable_ratelimit();
741 if (!try_module_get(cpufreq_driver->owner)) {
746 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
753 policy->cpus = cpumask_of_cpu(cpu);
755 /* Initially set CPU itself as the policy_cpu */
756 per_cpu(policy_cpu, cpu) = cpu;
757 lock_policy_rwsem_write(cpu);
759 init_completion(&policy->kobj_unregister);
760 INIT_WORK(&policy->update, handle_update);
762 /* call driver. From then on the cpufreq must be able
763 * to accept all calls to ->verify and ->setpolicy for this CPU
765 ret = cpufreq_driver->init(policy);
767 dprintk("initialization failed\n");
768 unlock_policy_rwsem_write(cpu);
771 policy->user_policy.min = policy->cpuinfo.min_freq;
772 policy->user_policy.max = policy->cpuinfo.max_freq;
773 policy->user_policy.governor = policy->governor;
776 for_each_cpu_mask(j, policy->cpus) {
780 /* check for existing affected CPUs. They may not be aware
781 * of it due to CPU Hotplug.
783 managed_policy = cpufreq_cpu_get(j);
784 if (unlikely(managed_policy)) {
786 /* Set proper policy_cpu */
787 unlock_policy_rwsem_write(cpu);
788 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
790 if (lock_policy_rwsem_write(cpu) < 0)
791 goto err_out_driver_exit;
793 spin_lock_irqsave(&cpufreq_driver_lock, flags);
794 managed_policy->cpus = policy->cpus;
795 cpufreq_cpu_data[cpu] = managed_policy;
796 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
798 dprintk("CPU already managed, adding link\n");
799 ret = sysfs_create_link(&sys_dev->kobj,
800 &managed_policy->kobj,
803 unlock_policy_rwsem_write(cpu);
804 goto err_out_driver_exit;
807 cpufreq_debug_enable_ratelimit();
809 unlock_policy_rwsem_write(cpu);
810 goto err_out_driver_exit; /* call driver->exit() */
814 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
816 /* prepare interface data */
817 policy->kobj.parent = &sys_dev->kobj;
818 policy->kobj.ktype = &ktype_cpufreq;
819 strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
821 ret = kobject_register(&policy->kobj);
823 unlock_policy_rwsem_write(cpu);
824 goto err_out_driver_exit;
826 /* set up files for this cpu device */
827 drv_attr = cpufreq_driver->attr;
828 while ((drv_attr) && (*drv_attr)) {
829 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
831 goto err_out_driver_exit;
834 if (cpufreq_driver->get){
835 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
837 goto err_out_driver_exit;
839 if (cpufreq_driver->target){
840 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
842 goto err_out_driver_exit;
845 spin_lock_irqsave(&cpufreq_driver_lock, flags);
846 for_each_cpu_mask(j, policy->cpus) {
847 cpufreq_cpu_data[j] = policy;
848 per_cpu(policy_cpu, j) = policy->cpu;
850 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
852 /* symlink affected CPUs */
853 for_each_cpu_mask(j, policy->cpus) {
859 dprintk("CPU %u already managed, adding link\n", j);
860 cpufreq_cpu_get(cpu);
861 cpu_sys_dev = get_cpu_sysdev(j);
862 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
865 unlock_policy_rwsem_write(cpu);
866 goto err_out_unregister;
870 policy->governor = NULL; /* to assure that the starting sequence is
871 * run in cpufreq_set_policy */
873 /* set default policy */
874 ret = __cpufreq_set_policy(policy, &new_policy);
875 policy->user_policy.policy = policy->policy;
877 unlock_policy_rwsem_write(cpu);
880 dprintk("setting policy failed\n");
881 goto err_out_unregister;
884 module_put(cpufreq_driver->owner);
885 dprintk("initialization complete\n");
886 cpufreq_debug_enable_ratelimit();
892 spin_lock_irqsave(&cpufreq_driver_lock, flags);
893 for_each_cpu_mask(j, policy->cpus)
894 cpufreq_cpu_data[j] = NULL;
895 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
897 kobject_unregister(&policy->kobj);
898 wait_for_completion(&policy->kobj_unregister);
901 if (cpufreq_driver->exit)
902 cpufreq_driver->exit(policy);
908 module_put(cpufreq_driver->owner);
910 cpufreq_debug_enable_ratelimit();
916 * __cpufreq_remove_dev - remove a CPU device
918 * Removes the cpufreq interface for a CPU device.
919 * Caller should already have policy_rwsem in write mode for this CPU.
920 * This routine frees the rwsem before returning.
922 static int __cpufreq_remove_dev (struct sys_device * sys_dev)
924 unsigned int cpu = sys_dev->id;
926 struct cpufreq_policy *data;
928 struct sys_device *cpu_sys_dev;
932 cpufreq_debug_disable_ratelimit();
933 dprintk("unregistering CPU %u\n", cpu);
935 spin_lock_irqsave(&cpufreq_driver_lock, flags);
936 data = cpufreq_cpu_data[cpu];
939 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
940 cpufreq_debug_enable_ratelimit();
941 unlock_policy_rwsem_write(cpu);
944 cpufreq_cpu_data[cpu] = NULL;
948 /* if this isn't the CPU which is the parent of the kobj, we
949 * only need to unlink, put and exit
951 if (unlikely(cpu != data->cpu)) {
952 dprintk("removing link\n");
953 cpu_clear(cpu, data->cpus);
954 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
955 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
956 cpufreq_cpu_put(data);
957 cpufreq_debug_enable_ratelimit();
958 unlock_policy_rwsem_write(cpu);
964 if (!kobject_get(&data->kobj)) {
965 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
966 cpufreq_debug_enable_ratelimit();
967 unlock_policy_rwsem_write(cpu);
972 /* if we have other CPUs still registered, we need to unlink them,
973 * or else wait_for_completion below will lock up. Clean the
974 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
977 if (unlikely(cpus_weight(data->cpus) > 1)) {
978 for_each_cpu_mask(j, data->cpus) {
981 cpufreq_cpu_data[j] = NULL;
985 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
987 if (unlikely(cpus_weight(data->cpus) > 1)) {
988 for_each_cpu_mask(j, data->cpus) {
991 dprintk("removing link for cpu %u\n", j);
992 cpu_sys_dev = get_cpu_sysdev(j);
993 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
994 cpufreq_cpu_put(data);
998 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1001 if (cpufreq_driver->target)
1002 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1004 unlock_policy_rwsem_write(cpu);
1006 kobject_unregister(&data->kobj);
1008 kobject_put(&data->kobj);
1010 /* we need to make sure that the underlying kobj is actually
1011 * not referenced anymore by anybody before we proceed with
1014 dprintk("waiting for dropping of refcount\n");
1015 wait_for_completion(&data->kobj_unregister);
1016 dprintk("wait complete\n");
1018 if (cpufreq_driver->exit)
1019 cpufreq_driver->exit(data);
1023 cpufreq_debug_enable_ratelimit();
1028 static int cpufreq_remove_dev (struct sys_device * sys_dev)
1030 unsigned int cpu = sys_dev->id;
1033 if (cpu_is_offline(cpu))
1036 if (unlikely(lock_policy_rwsem_write(cpu)))
1039 retval = __cpufreq_remove_dev(sys_dev);
1044 static void handle_update(struct work_struct *work)
1046 struct cpufreq_policy *policy =
1047 container_of(work, struct cpufreq_policy, update);
1048 unsigned int cpu = policy->cpu;
1049 dprintk("handle_update for cpu %u called\n", cpu);
1050 cpufreq_update_policy(cpu);
1054 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1056 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1057 * @new_freq: CPU frequency the CPU actually runs at
1059 * We adjust to current frequency first, and need to clean up later. So either call
1060 * to cpufreq_update_policy() or schedule handle_update()).
1062 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1063 unsigned int new_freq)
1065 struct cpufreq_freqs freqs;
1067 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1068 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1071 freqs.old = old_freq;
1072 freqs.new = new_freq;
1073 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1074 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1079 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1082 * This is the last known freq, without actually getting it from the driver.
1083 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1085 unsigned int cpufreq_quick_get(unsigned int cpu)
1087 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1088 unsigned int ret_freq = 0;
1091 if (unlikely(lock_policy_rwsem_read(cpu)))
1094 ret_freq = policy->cur;
1096 unlock_policy_rwsem_read(cpu);
1097 cpufreq_cpu_put(policy);
1102 EXPORT_SYMBOL(cpufreq_quick_get);
1105 static unsigned int __cpufreq_get(unsigned int cpu)
1107 struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1108 unsigned int ret_freq = 0;
1110 if (!cpufreq_driver->get)
1113 ret_freq = cpufreq_driver->get(cpu);
1115 if (ret_freq && policy->cur &&
1116 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1117 /* verify no discrepancy between actual and
1118 saved value exists */
1119 if (unlikely(ret_freq != policy->cur)) {
1120 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1121 schedule_work(&policy->update);
1129 * cpufreq_get - get the current CPU frequency (in kHz)
1132 * Get the CPU current (static) CPU frequency
1134 unsigned int cpufreq_get(unsigned int cpu)
1136 unsigned int ret_freq = 0;
1137 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1142 if (unlikely(lock_policy_rwsem_read(cpu)))
1145 ret_freq = __cpufreq_get(cpu);
1147 unlock_policy_rwsem_read(cpu);
1150 cpufreq_cpu_put(policy);
1154 EXPORT_SYMBOL(cpufreq_get);
1158 * cpufreq_suspend - let the low level driver prepare for suspend
1161 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
1163 int cpu = sysdev->id;
1165 unsigned int cur_freq = 0;
1166 struct cpufreq_policy *cpu_policy;
1168 dprintk("suspending cpu %u\n", cpu);
1170 if (!cpu_online(cpu))
1173 /* we may be lax here as interrupts are off. Nonetheless
1174 * we need to grab the correct cpu policy, as to check
1175 * whether we really run on this CPU.
1178 cpu_policy = cpufreq_cpu_get(cpu);
1182 /* only handle each CPU group once */
1183 if (unlikely(cpu_policy->cpu != cpu)) {
1184 cpufreq_cpu_put(cpu_policy);
1188 if (cpufreq_driver->suspend) {
1189 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1191 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1192 "step on CPU %u\n", cpu_policy->cpu);
1193 cpufreq_cpu_put(cpu_policy);
1199 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1202 if (cpufreq_driver->get)
1203 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1205 if (!cur_freq || !cpu_policy->cur) {
1206 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1207 "frequency is what timing core thinks it is.\n");
1211 if (unlikely(cur_freq != cpu_policy->cur)) {
1212 struct cpufreq_freqs freqs;
1214 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1215 dprintk("Warning: CPU frequency is %u, "
1216 "cpufreq assumed %u kHz.\n",
1217 cur_freq, cpu_policy->cur);
1220 freqs.old = cpu_policy->cur;
1221 freqs.new = cur_freq;
1223 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1224 CPUFREQ_SUSPENDCHANGE, &freqs);
1225 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1227 cpu_policy->cur = cur_freq;
1231 cpufreq_cpu_put(cpu_policy);
1236 * cpufreq_resume - restore proper CPU frequency handling after resume
1238 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1239 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1240 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1243 static int cpufreq_resume(struct sys_device * sysdev)
1245 int cpu = sysdev->id;
1247 struct cpufreq_policy *cpu_policy;
1249 dprintk("resuming cpu %u\n", cpu);
1251 if (!cpu_online(cpu))
1254 /* we may be lax here as interrupts are off. Nonetheless
1255 * we need to grab the correct cpu policy, as to check
1256 * whether we really run on this CPU.
1259 cpu_policy = cpufreq_cpu_get(cpu);
1263 /* only handle each CPU group once */
1264 if (unlikely(cpu_policy->cpu != cpu)) {
1265 cpufreq_cpu_put(cpu_policy);
1269 if (cpufreq_driver->resume) {
1270 ret = cpufreq_driver->resume(cpu_policy);
1272 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1273 "step on CPU %u\n", cpu_policy->cpu);
1274 cpufreq_cpu_put(cpu_policy);
1279 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1280 unsigned int cur_freq = 0;
1282 if (cpufreq_driver->get)
1283 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1285 if (!cur_freq || !cpu_policy->cur) {
1286 printk(KERN_ERR "cpufreq: resume failed to assert "
1287 "current frequency is what timing core "
1292 if (unlikely(cur_freq != cpu_policy->cur)) {
1293 struct cpufreq_freqs freqs;
1295 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1296 dprintk("Warning: CPU frequency"
1297 "is %u, cpufreq assumed %u kHz.\n",
1298 cur_freq, cpu_policy->cur);
1301 freqs.old = cpu_policy->cur;
1302 freqs.new = cur_freq;
1304 srcu_notifier_call_chain(
1305 &cpufreq_transition_notifier_list,
1306 CPUFREQ_RESUMECHANGE, &freqs);
1307 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1309 cpu_policy->cur = cur_freq;
1314 schedule_work(&cpu_policy->update);
1315 cpufreq_cpu_put(cpu_policy);
1319 static struct sysdev_driver cpufreq_sysdev_driver = {
1320 .add = cpufreq_add_dev,
1321 .remove = cpufreq_remove_dev,
1322 .suspend = cpufreq_suspend,
1323 .resume = cpufreq_resume,
1327 /*********************************************************************
1328 * NOTIFIER LISTS INTERFACE *
1329 *********************************************************************/
1332 * cpufreq_register_notifier - register a driver with cpufreq
1333 * @nb: notifier function to register
1334 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1336 * Add a driver to one of two lists: either a list of drivers that
1337 * are notified about clock rate changes (once before and once after
1338 * the transition), or a list of drivers that are notified about
1339 * changes in cpufreq policy.
1341 * This function may sleep, and has the same return conditions as
1342 * blocking_notifier_chain_register.
1344 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1349 case CPUFREQ_TRANSITION_NOTIFIER:
1350 ret = srcu_notifier_chain_register(
1351 &cpufreq_transition_notifier_list, nb);
1353 case CPUFREQ_POLICY_NOTIFIER:
1354 ret = blocking_notifier_chain_register(
1355 &cpufreq_policy_notifier_list, nb);
1363 EXPORT_SYMBOL(cpufreq_register_notifier);
1367 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1368 * @nb: notifier block to be unregistered
1369 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1371 * Remove a driver from the CPU frequency notifier list.
1373 * This function may sleep, and has the same return conditions as
1374 * blocking_notifier_chain_unregister.
1376 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1381 case CPUFREQ_TRANSITION_NOTIFIER:
1382 ret = srcu_notifier_chain_unregister(
1383 &cpufreq_transition_notifier_list, nb);
1385 case CPUFREQ_POLICY_NOTIFIER:
1386 ret = blocking_notifier_chain_unregister(
1387 &cpufreq_policy_notifier_list, nb);
1395 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1398 /*********************************************************************
1400 *********************************************************************/
1403 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1404 unsigned int target_freq,
1405 unsigned int relation)
1407 int retval = -EINVAL;
1409 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1410 target_freq, relation);
1411 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1412 retval = cpufreq_driver->target(policy, target_freq, relation);
1416 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1418 int cpufreq_driver_target(struct cpufreq_policy *policy,
1419 unsigned int target_freq,
1420 unsigned int relation)
1424 policy = cpufreq_cpu_get(policy->cpu);
1428 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1431 ret = __cpufreq_driver_target(policy, target_freq, relation);
1433 unlock_policy_rwsem_write(policy->cpu);
1435 cpufreq_cpu_put(policy);
1438 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1440 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1444 policy = cpufreq_cpu_get(policy->cpu);
1448 if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1449 ret = cpufreq_driver->getavg(policy->cpu);
1451 cpufreq_cpu_put(policy);
1454 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1457 * when "event" is CPUFREQ_GOV_LIMITS
1460 static int __cpufreq_governor(struct cpufreq_policy *policy,
1465 if (!try_module_get(policy->governor->owner))
1468 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1469 policy->cpu, event);
1470 ret = policy->governor->governor(policy, event);
1472 /* we keep one module reference alive for
1473 each CPU governed by this CPU */
1474 if ((event != CPUFREQ_GOV_START) || ret)
1475 module_put(policy->governor->owner);
1476 if ((event == CPUFREQ_GOV_STOP) && !ret)
1477 module_put(policy->governor->owner);
1483 int cpufreq_register_governor(struct cpufreq_governor *governor)
1490 mutex_lock(&cpufreq_governor_mutex);
1493 if (__find_governor(governor->name) == NULL) {
1495 list_add(&governor->governor_list, &cpufreq_governor_list);
1498 mutex_unlock(&cpufreq_governor_mutex);
1501 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1504 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1509 mutex_lock(&cpufreq_governor_mutex);
1510 list_del(&governor->governor_list);
1511 mutex_unlock(&cpufreq_governor_mutex);
1514 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1518 /*********************************************************************
1519 * POLICY INTERFACE *
1520 *********************************************************************/
1523 * cpufreq_get_policy - get the current cpufreq_policy
1524 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1526 * Reads the current cpufreq policy.
1528 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1530 struct cpufreq_policy *cpu_policy;
1534 cpu_policy = cpufreq_cpu_get(cpu);
1538 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1540 cpufreq_cpu_put(cpu_policy);
1543 EXPORT_SYMBOL(cpufreq_get_policy);
1547 * data : current policy.
1548 * policy : policy to be set.
1550 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1551 struct cpufreq_policy *policy)
1555 cpufreq_debug_disable_ratelimit();
1556 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1557 policy->min, policy->max);
1559 memcpy(&policy->cpuinfo, &data->cpuinfo,
1560 sizeof(struct cpufreq_cpuinfo));
1562 if (policy->min > data->min && policy->min > policy->max) {
1567 /* verify the cpu speed can be set within this limit */
1568 ret = cpufreq_driver->verify(policy);
1572 /* adjust if necessary - all reasons */
1573 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1574 CPUFREQ_ADJUST, policy);
1576 /* adjust if necessary - hardware incompatibility*/
1577 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1578 CPUFREQ_INCOMPATIBLE, policy);
1580 /* verify the cpu speed can be set within this limit,
1581 which might be different to the first one */
1582 ret = cpufreq_driver->verify(policy);
1586 /* notification of the new policy */
1587 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1588 CPUFREQ_NOTIFY, policy);
1590 data->min = policy->min;
1591 data->max = policy->max;
1593 dprintk("new min and max freqs are %u - %u kHz\n",
1594 data->min, data->max);
1596 if (cpufreq_driver->setpolicy) {
1597 data->policy = policy->policy;
1598 dprintk("setting range\n");
1599 ret = cpufreq_driver->setpolicy(policy);
1601 if (policy->governor != data->governor) {
1602 /* save old, working values */
1603 struct cpufreq_governor *old_gov = data->governor;
1605 dprintk("governor switch\n");
1607 /* end old governor */
1609 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1611 /* start new governor */
1612 data->governor = policy->governor;
1613 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1614 /* new governor failed, so re-start old one */
1615 dprintk("starting governor %s failed\n",
1616 data->governor->name);
1618 data->governor = old_gov;
1619 __cpufreq_governor(data,
1625 /* might be a policy change, too, so fall through */
1627 dprintk("governor: change or update limits\n");
1628 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1632 cpufreq_debug_enable_ratelimit();
1637 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1638 * @cpu: CPU which shall be re-evaluated
1640 * Usefull for policy notifiers which have different necessities
1641 * at different times.
1643 int cpufreq_update_policy(unsigned int cpu)
1645 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1646 struct cpufreq_policy policy;
1652 if (unlikely(lock_policy_rwsem_write(cpu)))
1655 dprintk("updating policy for CPU %u\n", cpu);
1656 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1657 policy.min = data->user_policy.min;
1658 policy.max = data->user_policy.max;
1659 policy.policy = data->user_policy.policy;
1660 policy.governor = data->user_policy.governor;
1662 /* BIOS might change freq behind our back
1663 -> ask driver for current freq and notify governors about a change */
1664 if (cpufreq_driver->get) {
1665 policy.cur = cpufreq_driver->get(cpu);
1667 dprintk("Driver did not initialize current freq");
1668 data->cur = policy.cur;
1670 if (data->cur != policy.cur)
1671 cpufreq_out_of_sync(cpu, data->cur,
1676 ret = __cpufreq_set_policy(data, &policy);
1678 unlock_policy_rwsem_write(cpu);
1680 cpufreq_cpu_put(data);
1683 EXPORT_SYMBOL(cpufreq_update_policy);
1685 static int cpufreq_cpu_callback(struct notifier_block *nfb,
1686 unsigned long action, void *hcpu)
1688 unsigned int cpu = (unsigned long)hcpu;
1689 struct sys_device *sys_dev;
1690 struct cpufreq_policy *policy;
1692 sys_dev = get_cpu_sysdev(cpu);
1696 case CPU_ONLINE_FROZEN:
1697 cpufreq_add_dev(sys_dev);
1699 case CPU_DOWN_PREPARE:
1700 case CPU_DOWN_PREPARE_FROZEN:
1701 if (unlikely(lock_policy_rwsem_write(cpu)))
1704 policy = cpufreq_cpu_data[cpu];
1706 __cpufreq_driver_target(policy, policy->min,
1707 CPUFREQ_RELATION_H);
1709 __cpufreq_remove_dev(sys_dev);
1711 case CPU_DOWN_FAILED:
1712 case CPU_DOWN_FAILED_FROZEN:
1713 cpufreq_add_dev(sys_dev);
1720 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1722 .notifier_call = cpufreq_cpu_callback,
1725 /*********************************************************************
1726 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1727 *********************************************************************/
1730 * cpufreq_register_driver - register a CPU Frequency driver
1731 * @driver_data: A struct cpufreq_driver containing the values#
1732 * submitted by the CPU Frequency driver.
1734 * Registers a CPU Frequency driver to this core code. This code
1735 * returns zero on success, -EBUSY when another driver got here first
1736 * (and isn't unregistered in the meantime).
1739 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1741 unsigned long flags;
1744 if (!driver_data || !driver_data->verify || !driver_data->init ||
1745 ((!driver_data->setpolicy) && (!driver_data->target)))
1748 dprintk("trying to register driver %s\n", driver_data->name);
1750 if (driver_data->setpolicy)
1751 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1753 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1754 if (cpufreq_driver) {
1755 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1758 cpufreq_driver = driver_data;
1759 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1761 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1763 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1767 /* check for at least one working CPU */
1768 for (i=0; i<NR_CPUS; i++)
1769 if (cpufreq_cpu_data[i])
1772 /* if all ->init() calls failed, unregister */
1774 dprintk("no CPU initialized for driver %s\n",
1776 sysdev_driver_unregister(&cpu_sysdev_class,
1777 &cpufreq_sysdev_driver);
1779 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1780 cpufreq_driver = NULL;
1781 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1786 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1787 dprintk("driver %s up and running\n", driver_data->name);
1788 cpufreq_debug_enable_ratelimit();
1793 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1797 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1799 * Unregister the current CPUFreq driver. Only call this if you have
1800 * the right to do so, i.e. if you have succeeded in initialising before!
1801 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1802 * currently not initialised.
1804 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1806 unsigned long flags;
1808 cpufreq_debug_disable_ratelimit();
1810 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1811 cpufreq_debug_enable_ratelimit();
1815 dprintk("unregistering driver %s\n", driver->name);
1817 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1818 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1820 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1821 cpufreq_driver = NULL;
1822 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1826 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1828 static int __init cpufreq_core_init(void)
1832 for_each_possible_cpu(cpu) {
1833 per_cpu(policy_cpu, cpu) = -1;
1834 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1839 core_initcall(cpufreq_core_init);