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,
509 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
510 return sprintf(buf, "powersave\n");
511 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
512 return sprintf(buf, "performance\n");
513 else if (policy->governor)
514 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
520 * store_scaling_governor - store policy for the specified CPU
522 static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
523 const char *buf, size_t count)
525 unsigned int ret = -EINVAL;
526 char str_governor[16];
527 struct cpufreq_policy new_policy;
529 ret = cpufreq_get_policy(&new_policy, policy->cpu);
533 ret = sscanf (buf, "%15s", str_governor);
537 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
538 &new_policy.governor))
541 /* Do not use cpufreq_set_policy here or the user_policy.max
542 will be wrongly overridden */
543 ret = __cpufreq_set_policy(policy, &new_policy);
545 policy->user_policy.policy = policy->policy;
546 policy->user_policy.governor = policy->governor;
555 * show_scaling_driver - show the cpufreq driver currently loaded
557 static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
559 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
563 * show_scaling_available_governors - show the available CPUfreq governors
565 static ssize_t show_scaling_available_governors (struct cpufreq_policy *policy,
569 struct cpufreq_governor *t;
571 if (!cpufreq_driver->target) {
572 i += sprintf(buf, "performance powersave");
576 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
577 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
579 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
582 i += sprintf(&buf[i], "\n");
586 * show_affected_cpus - show the CPUs affected by each transition
588 static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
593 for_each_cpu_mask(cpu, policy->cpus) {
595 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
596 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
597 if (i >= (PAGE_SIZE - 5))
600 i += sprintf(&buf[i], "\n");
605 #define define_one_ro(_name) \
606 static struct freq_attr _name = \
607 __ATTR(_name, 0444, show_##_name, NULL)
609 #define define_one_ro0400(_name) \
610 static struct freq_attr _name = \
611 __ATTR(_name, 0400, show_##_name, NULL)
613 #define define_one_rw(_name) \
614 static struct freq_attr _name = \
615 __ATTR(_name, 0644, show_##_name, store_##_name)
617 define_one_ro0400(cpuinfo_cur_freq);
618 define_one_ro(cpuinfo_min_freq);
619 define_one_ro(cpuinfo_max_freq);
620 define_one_ro(scaling_available_governors);
621 define_one_ro(scaling_driver);
622 define_one_ro(scaling_cur_freq);
623 define_one_ro(affected_cpus);
624 define_one_rw(scaling_min_freq);
625 define_one_rw(scaling_max_freq);
626 define_one_rw(scaling_governor);
628 static struct attribute * default_attrs[] = {
629 &cpuinfo_min_freq.attr,
630 &cpuinfo_max_freq.attr,
631 &scaling_min_freq.attr,
632 &scaling_max_freq.attr,
634 &scaling_governor.attr,
635 &scaling_driver.attr,
636 &scaling_available_governors.attr,
640 #define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
641 #define to_attr(a) container_of(a,struct freq_attr,attr)
643 static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
645 struct cpufreq_policy * policy = to_policy(kobj);
646 struct freq_attr * fattr = to_attr(attr);
648 policy = cpufreq_cpu_get(policy->cpu);
652 if (lock_policy_rwsem_read(policy->cpu) < 0)
656 ret = fattr->show(policy, buf);
660 unlock_policy_rwsem_read(policy->cpu);
662 cpufreq_cpu_put(policy);
666 static ssize_t store(struct kobject * kobj, struct attribute * attr,
667 const char * buf, size_t count)
669 struct cpufreq_policy * policy = to_policy(kobj);
670 struct freq_attr * fattr = to_attr(attr);
672 policy = cpufreq_cpu_get(policy->cpu);
676 if (lock_policy_rwsem_write(policy->cpu) < 0)
680 ret = fattr->store(policy, buf, count);
684 unlock_policy_rwsem_write(policy->cpu);
686 cpufreq_cpu_put(policy);
690 static void cpufreq_sysfs_release(struct kobject * kobj)
692 struct cpufreq_policy * policy = to_policy(kobj);
693 dprintk("last reference is dropped\n");
694 complete(&policy->kobj_unregister);
697 static struct sysfs_ops sysfs_ops = {
702 static struct kobj_type ktype_cpufreq = {
703 .sysfs_ops = &sysfs_ops,
704 .default_attrs = default_attrs,
705 .release = cpufreq_sysfs_release,
710 * cpufreq_add_dev - add a CPU device
712 * Adds the cpufreq interface for a CPU device.
714 static int cpufreq_add_dev (struct sys_device * sys_dev)
716 unsigned int cpu = sys_dev->id;
718 struct cpufreq_policy new_policy;
719 struct cpufreq_policy *policy;
720 struct freq_attr **drv_attr;
721 struct sys_device *cpu_sys_dev;
725 struct cpufreq_policy *managed_policy;
728 if (cpu_is_offline(cpu))
731 cpufreq_debug_disable_ratelimit();
732 dprintk("adding CPU %u\n", cpu);
735 /* check whether a different CPU already registered this
736 * CPU because it is in the same boat. */
737 policy = cpufreq_cpu_get(cpu);
738 if (unlikely(policy)) {
739 cpufreq_cpu_put(policy);
740 cpufreq_debug_enable_ratelimit();
745 if (!try_module_get(cpufreq_driver->owner)) {
750 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
757 policy->cpus = cpumask_of_cpu(cpu);
759 /* Initially set CPU itself as the policy_cpu */
760 per_cpu(policy_cpu, cpu) = cpu;
761 lock_policy_rwsem_write(cpu);
763 init_completion(&policy->kobj_unregister);
764 INIT_WORK(&policy->update, handle_update);
766 /* Set governor before ->init, so that driver could check it */
767 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
768 /* call driver. From then on the cpufreq must be able
769 * to accept all calls to ->verify and ->setpolicy for this CPU
771 ret = cpufreq_driver->init(policy);
773 dprintk("initialization failed\n");
774 unlock_policy_rwsem_write(cpu);
777 policy->user_policy.min = policy->cpuinfo.min_freq;
778 policy->user_policy.max = policy->cpuinfo.max_freq;
782 #ifdef CONFIG_HOTPLUG_CPU
783 if (cpufreq_cpu_governor[cpu]){
784 policy->governor = cpufreq_cpu_governor[cpu];
785 dprintk("Restoring governor %s for cpu %d\n",
786 policy->governor->name, cpu);
790 for_each_cpu_mask(j, policy->cpus) {
794 /* check for existing affected CPUs. They may not be aware
795 * of it due to CPU Hotplug.
797 managed_policy = cpufreq_cpu_get(j);
798 if (unlikely(managed_policy)) {
800 /* Set proper policy_cpu */
801 unlock_policy_rwsem_write(cpu);
802 per_cpu(policy_cpu, cpu) = managed_policy->cpu;
804 if (lock_policy_rwsem_write(cpu) < 0)
805 goto err_out_driver_exit;
807 spin_lock_irqsave(&cpufreq_driver_lock, flags);
808 managed_policy->cpus = policy->cpus;
809 cpufreq_cpu_data[cpu] = managed_policy;
810 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
812 dprintk("CPU already managed, adding link\n");
813 ret = sysfs_create_link(&sys_dev->kobj,
814 &managed_policy->kobj,
817 unlock_policy_rwsem_write(cpu);
818 goto err_out_driver_exit;
821 cpufreq_debug_enable_ratelimit();
823 unlock_policy_rwsem_write(cpu);
824 goto err_out_driver_exit; /* call driver->exit() */
828 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
830 /* prepare interface data */
831 policy->kobj.parent = &sys_dev->kobj;
832 policy->kobj.ktype = &ktype_cpufreq;
833 strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
835 ret = kobject_register(&policy->kobj);
837 unlock_policy_rwsem_write(cpu);
838 goto err_out_driver_exit;
840 /* set up files for this cpu device */
841 drv_attr = cpufreq_driver->attr;
842 while ((drv_attr) && (*drv_attr)) {
843 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
845 goto err_out_driver_exit;
848 if (cpufreq_driver->get){
849 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
851 goto err_out_driver_exit;
853 if (cpufreq_driver->target){
854 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
856 goto err_out_driver_exit;
859 spin_lock_irqsave(&cpufreq_driver_lock, flags);
860 for_each_cpu_mask(j, policy->cpus) {
861 cpufreq_cpu_data[j] = policy;
862 per_cpu(policy_cpu, j) = policy->cpu;
864 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
866 /* symlink affected CPUs */
867 for_each_cpu_mask(j, policy->cpus) {
873 dprintk("CPU %u already managed, adding link\n", j);
874 cpufreq_cpu_get(cpu);
875 cpu_sys_dev = get_cpu_sysdev(j);
876 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
879 unlock_policy_rwsem_write(cpu);
880 goto err_out_unregister;
884 policy->governor = NULL; /* to assure that the starting sequence is
885 * run in cpufreq_set_policy */
887 /* set default policy */
888 ret = __cpufreq_set_policy(policy, &new_policy);
889 policy->user_policy.policy = policy->policy;
890 policy->user_policy.governor = policy->governor;
892 unlock_policy_rwsem_write(cpu);
895 dprintk("setting policy failed\n");
896 goto err_out_unregister;
899 module_put(cpufreq_driver->owner);
900 dprintk("initialization complete\n");
901 cpufreq_debug_enable_ratelimit();
907 spin_lock_irqsave(&cpufreq_driver_lock, flags);
908 for_each_cpu_mask(j, policy->cpus)
909 cpufreq_cpu_data[j] = NULL;
910 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
912 kobject_unregister(&policy->kobj);
913 wait_for_completion(&policy->kobj_unregister);
916 if (cpufreq_driver->exit)
917 cpufreq_driver->exit(policy);
923 module_put(cpufreq_driver->owner);
925 cpufreq_debug_enable_ratelimit();
931 * __cpufreq_remove_dev - remove a CPU device
933 * Removes the cpufreq interface for a CPU device.
934 * Caller should already have policy_rwsem in write mode for this CPU.
935 * This routine frees the rwsem before returning.
937 static int __cpufreq_remove_dev (struct sys_device * sys_dev)
939 unsigned int cpu = sys_dev->id;
941 struct cpufreq_policy *data;
943 struct sys_device *cpu_sys_dev;
947 cpufreq_debug_disable_ratelimit();
948 dprintk("unregistering CPU %u\n", cpu);
950 spin_lock_irqsave(&cpufreq_driver_lock, flags);
951 data = cpufreq_cpu_data[cpu];
954 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
955 cpufreq_debug_enable_ratelimit();
956 unlock_policy_rwsem_write(cpu);
959 cpufreq_cpu_data[cpu] = NULL;
963 /* if this isn't the CPU which is the parent of the kobj, we
964 * only need to unlink, put and exit
966 if (unlikely(cpu != data->cpu)) {
967 dprintk("removing link\n");
968 cpu_clear(cpu, data->cpus);
969 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
970 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
971 cpufreq_cpu_put(data);
972 cpufreq_debug_enable_ratelimit();
973 unlock_policy_rwsem_write(cpu);
979 if (!kobject_get(&data->kobj)) {
980 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
981 cpufreq_debug_enable_ratelimit();
982 unlock_policy_rwsem_write(cpu);
988 #ifdef CONFIG_HOTPLUG_CPU
989 cpufreq_cpu_governor[cpu] = data->governor;
992 /* if we have other CPUs still registered, we need to unlink them,
993 * or else wait_for_completion below will lock up. Clean the
994 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
997 if (unlikely(cpus_weight(data->cpus) > 1)) {
998 for_each_cpu_mask(j, data->cpus) {
1001 cpufreq_cpu_data[j] = NULL;
1005 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1007 if (unlikely(cpus_weight(data->cpus) > 1)) {
1008 for_each_cpu_mask(j, data->cpus) {
1011 dprintk("removing link for cpu %u\n", j);
1012 #ifdef CONFIG_HOTPLUG_CPU
1013 cpufreq_cpu_governor[j] = data->governor;
1015 cpu_sys_dev = get_cpu_sysdev(j);
1016 sysfs_remove_link(&cpu_sys_dev->kobj, "cpufreq");
1017 cpufreq_cpu_put(data);
1021 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1024 if (cpufreq_driver->target)
1025 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1027 unlock_policy_rwsem_write(cpu);
1029 kobject_unregister(&data->kobj);
1031 kobject_put(&data->kobj);
1033 /* we need to make sure that the underlying kobj is actually
1034 * not referenced anymore by anybody before we proceed with
1037 dprintk("waiting for dropping of refcount\n");
1038 wait_for_completion(&data->kobj_unregister);
1039 dprintk("wait complete\n");
1041 if (cpufreq_driver->exit)
1042 cpufreq_driver->exit(data);
1046 cpufreq_debug_enable_ratelimit();
1051 static int cpufreq_remove_dev (struct sys_device * sys_dev)
1053 unsigned int cpu = sys_dev->id;
1056 if (cpu_is_offline(cpu))
1059 if (unlikely(lock_policy_rwsem_write(cpu)))
1062 retval = __cpufreq_remove_dev(sys_dev);
1067 static void handle_update(struct work_struct *work)
1069 struct cpufreq_policy *policy =
1070 container_of(work, struct cpufreq_policy, update);
1071 unsigned int cpu = policy->cpu;
1072 dprintk("handle_update for cpu %u called\n", cpu);
1073 cpufreq_update_policy(cpu);
1077 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1079 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1080 * @new_freq: CPU frequency the CPU actually runs at
1082 * We adjust to current frequency first, and need to clean up later. So either call
1083 * to cpufreq_update_policy() or schedule handle_update()).
1085 static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1086 unsigned int new_freq)
1088 struct cpufreq_freqs freqs;
1090 dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
1091 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1094 freqs.old = old_freq;
1095 freqs.new = new_freq;
1096 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1097 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1102 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1105 * This is the last known freq, without actually getting it from the driver.
1106 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1108 unsigned int cpufreq_quick_get(unsigned int cpu)
1110 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1111 unsigned int ret_freq = 0;
1114 if (unlikely(lock_policy_rwsem_read(cpu)))
1117 ret_freq = policy->cur;
1119 unlock_policy_rwsem_read(cpu);
1120 cpufreq_cpu_put(policy);
1125 EXPORT_SYMBOL(cpufreq_quick_get);
1128 static unsigned int __cpufreq_get(unsigned int cpu)
1130 struct cpufreq_policy *policy = cpufreq_cpu_data[cpu];
1131 unsigned int ret_freq = 0;
1133 if (!cpufreq_driver->get)
1136 ret_freq = cpufreq_driver->get(cpu);
1138 if (ret_freq && policy->cur &&
1139 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1140 /* verify no discrepancy between actual and
1141 saved value exists */
1142 if (unlikely(ret_freq != policy->cur)) {
1143 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1144 schedule_work(&policy->update);
1152 * cpufreq_get - get the current CPU frequency (in kHz)
1155 * Get the CPU current (static) CPU frequency
1157 unsigned int cpufreq_get(unsigned int cpu)
1159 unsigned int ret_freq = 0;
1160 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1165 if (unlikely(lock_policy_rwsem_read(cpu)))
1168 ret_freq = __cpufreq_get(cpu);
1170 unlock_policy_rwsem_read(cpu);
1173 cpufreq_cpu_put(policy);
1177 EXPORT_SYMBOL(cpufreq_get);
1181 * cpufreq_suspend - let the low level driver prepare for suspend
1184 static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
1186 int cpu = sysdev->id;
1188 unsigned int cur_freq = 0;
1189 struct cpufreq_policy *cpu_policy;
1191 dprintk("suspending cpu %u\n", cpu);
1193 if (!cpu_online(cpu))
1196 /* we may be lax here as interrupts are off. Nonetheless
1197 * we need to grab the correct cpu policy, as to check
1198 * whether we really run on this CPU.
1201 cpu_policy = cpufreq_cpu_get(cpu);
1205 /* only handle each CPU group once */
1206 if (unlikely(cpu_policy->cpu != cpu)) {
1207 cpufreq_cpu_put(cpu_policy);
1211 if (cpufreq_driver->suspend) {
1212 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
1214 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1215 "step on CPU %u\n", cpu_policy->cpu);
1216 cpufreq_cpu_put(cpu_policy);
1222 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
1225 if (cpufreq_driver->get)
1226 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1228 if (!cur_freq || !cpu_policy->cur) {
1229 printk(KERN_ERR "cpufreq: suspend failed to assert current "
1230 "frequency is what timing core thinks it is.\n");
1234 if (unlikely(cur_freq != cpu_policy->cur)) {
1235 struct cpufreq_freqs freqs;
1237 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1238 dprintk("Warning: CPU frequency is %u, "
1239 "cpufreq assumed %u kHz.\n",
1240 cur_freq, cpu_policy->cur);
1243 freqs.old = cpu_policy->cur;
1244 freqs.new = cur_freq;
1246 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
1247 CPUFREQ_SUSPENDCHANGE, &freqs);
1248 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
1250 cpu_policy->cur = cur_freq;
1254 cpufreq_cpu_put(cpu_policy);
1259 * cpufreq_resume - restore proper CPU frequency handling after resume
1261 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1262 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
1263 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
1266 static int cpufreq_resume(struct sys_device * sysdev)
1268 int cpu = sysdev->id;
1270 struct cpufreq_policy *cpu_policy;
1272 dprintk("resuming cpu %u\n", cpu);
1274 if (!cpu_online(cpu))
1277 /* we may be lax here as interrupts are off. Nonetheless
1278 * we need to grab the correct cpu policy, as to check
1279 * whether we really run on this CPU.
1282 cpu_policy = cpufreq_cpu_get(cpu);
1286 /* only handle each CPU group once */
1287 if (unlikely(cpu_policy->cpu != cpu)) {
1288 cpufreq_cpu_put(cpu_policy);
1292 if (cpufreq_driver->resume) {
1293 ret = cpufreq_driver->resume(cpu_policy);
1295 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1296 "step on CPU %u\n", cpu_policy->cpu);
1297 cpufreq_cpu_put(cpu_policy);
1302 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1303 unsigned int cur_freq = 0;
1305 if (cpufreq_driver->get)
1306 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
1308 if (!cur_freq || !cpu_policy->cur) {
1309 printk(KERN_ERR "cpufreq: resume failed to assert "
1310 "current frequency is what timing core "
1315 if (unlikely(cur_freq != cpu_policy->cur)) {
1316 struct cpufreq_freqs freqs;
1318 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
1319 dprintk("Warning: CPU frequency"
1320 "is %u, cpufreq assumed %u kHz.\n",
1321 cur_freq, cpu_policy->cur);
1324 freqs.old = cpu_policy->cur;
1325 freqs.new = cur_freq;
1327 srcu_notifier_call_chain(
1328 &cpufreq_transition_notifier_list,
1329 CPUFREQ_RESUMECHANGE, &freqs);
1330 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1332 cpu_policy->cur = cur_freq;
1337 schedule_work(&cpu_policy->update);
1338 cpufreq_cpu_put(cpu_policy);
1342 static struct sysdev_driver cpufreq_sysdev_driver = {
1343 .add = cpufreq_add_dev,
1344 .remove = cpufreq_remove_dev,
1345 .suspend = cpufreq_suspend,
1346 .resume = cpufreq_resume,
1350 /*********************************************************************
1351 * NOTIFIER LISTS INTERFACE *
1352 *********************************************************************/
1355 * cpufreq_register_notifier - register a driver with cpufreq
1356 * @nb: notifier function to register
1357 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1359 * Add a driver to one of two lists: either a list of drivers that
1360 * are notified about clock rate changes (once before and once after
1361 * the transition), or a list of drivers that are notified about
1362 * changes in cpufreq policy.
1364 * This function may sleep, and has the same return conditions as
1365 * blocking_notifier_chain_register.
1367 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1372 case CPUFREQ_TRANSITION_NOTIFIER:
1373 ret = srcu_notifier_chain_register(
1374 &cpufreq_transition_notifier_list, nb);
1376 case CPUFREQ_POLICY_NOTIFIER:
1377 ret = blocking_notifier_chain_register(
1378 &cpufreq_policy_notifier_list, nb);
1386 EXPORT_SYMBOL(cpufreq_register_notifier);
1390 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1391 * @nb: notifier block to be unregistered
1392 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1394 * Remove a driver from the CPU frequency notifier list.
1396 * This function may sleep, and has the same return conditions as
1397 * blocking_notifier_chain_unregister.
1399 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1404 case CPUFREQ_TRANSITION_NOTIFIER:
1405 ret = srcu_notifier_chain_unregister(
1406 &cpufreq_transition_notifier_list, nb);
1408 case CPUFREQ_POLICY_NOTIFIER:
1409 ret = blocking_notifier_chain_unregister(
1410 &cpufreq_policy_notifier_list, nb);
1418 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1421 /*********************************************************************
1423 *********************************************************************/
1426 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1427 unsigned int target_freq,
1428 unsigned int relation)
1430 int retval = -EINVAL;
1432 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1433 target_freq, relation);
1434 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1435 retval = cpufreq_driver->target(policy, target_freq, relation);
1439 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1441 int cpufreq_driver_target(struct cpufreq_policy *policy,
1442 unsigned int target_freq,
1443 unsigned int relation)
1447 policy = cpufreq_cpu_get(policy->cpu);
1451 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1454 ret = __cpufreq_driver_target(policy, target_freq, relation);
1456 unlock_policy_rwsem_write(policy->cpu);
1458 cpufreq_cpu_put(policy);
1461 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1463 int __cpufreq_driver_getavg(struct cpufreq_policy *policy)
1467 policy = cpufreq_cpu_get(policy->cpu);
1471 if (cpu_online(policy->cpu) && cpufreq_driver->getavg)
1472 ret = cpufreq_driver->getavg(policy->cpu);
1474 cpufreq_cpu_put(policy);
1477 EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1480 * when "event" is CPUFREQ_GOV_LIMITS
1483 static int __cpufreq_governor(struct cpufreq_policy *policy,
1488 if (!try_module_get(policy->governor->owner))
1491 dprintk("__cpufreq_governor for CPU %u, event %u\n",
1492 policy->cpu, event);
1493 ret = policy->governor->governor(policy, event);
1495 /* we keep one module reference alive for
1496 each CPU governed by this CPU */
1497 if ((event != CPUFREQ_GOV_START) || ret)
1498 module_put(policy->governor->owner);
1499 if ((event == CPUFREQ_GOV_STOP) && !ret)
1500 module_put(policy->governor->owner);
1506 int cpufreq_register_governor(struct cpufreq_governor *governor)
1513 mutex_lock(&cpufreq_governor_mutex);
1516 if (__find_governor(governor->name) == NULL) {
1518 list_add(&governor->governor_list, &cpufreq_governor_list);
1521 mutex_unlock(&cpufreq_governor_mutex);
1524 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1527 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1532 mutex_lock(&cpufreq_governor_mutex);
1533 list_del(&governor->governor_list);
1534 mutex_unlock(&cpufreq_governor_mutex);
1537 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1541 /*********************************************************************
1542 * POLICY INTERFACE *
1543 *********************************************************************/
1546 * cpufreq_get_policy - get the current cpufreq_policy
1547 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1549 * Reads the current cpufreq policy.
1551 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1553 struct cpufreq_policy *cpu_policy;
1557 cpu_policy = cpufreq_cpu_get(cpu);
1561 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1563 cpufreq_cpu_put(cpu_policy);
1566 EXPORT_SYMBOL(cpufreq_get_policy);
1570 * data : current policy.
1571 * policy : policy to be set.
1573 static int __cpufreq_set_policy(struct cpufreq_policy *data,
1574 struct cpufreq_policy *policy)
1578 cpufreq_debug_disable_ratelimit();
1579 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1580 policy->min, policy->max);
1582 memcpy(&policy->cpuinfo, &data->cpuinfo,
1583 sizeof(struct cpufreq_cpuinfo));
1585 if (policy->min > data->min && policy->min > policy->max) {
1590 /* verify the cpu speed can be set within this limit */
1591 ret = cpufreq_driver->verify(policy);
1595 /* adjust if necessary - all reasons */
1596 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1597 CPUFREQ_ADJUST, policy);
1599 /* adjust if necessary - hardware incompatibility*/
1600 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1601 CPUFREQ_INCOMPATIBLE, policy);
1603 /* verify the cpu speed can be set within this limit,
1604 which might be different to the first one */
1605 ret = cpufreq_driver->verify(policy);
1609 /* notification of the new policy */
1610 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1611 CPUFREQ_NOTIFY, policy);
1613 data->min = policy->min;
1614 data->max = policy->max;
1616 dprintk("new min and max freqs are %u - %u kHz\n",
1617 data->min, data->max);
1619 if (cpufreq_driver->setpolicy) {
1620 data->policy = policy->policy;
1621 dprintk("setting range\n");
1622 ret = cpufreq_driver->setpolicy(policy);
1624 if (policy->governor != data->governor) {
1625 /* save old, working values */
1626 struct cpufreq_governor *old_gov = data->governor;
1628 dprintk("governor switch\n");
1630 /* end old governor */
1632 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1634 /* start new governor */
1635 data->governor = policy->governor;
1636 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1637 /* new governor failed, so re-start old one */
1638 dprintk("starting governor %s failed\n",
1639 data->governor->name);
1641 data->governor = old_gov;
1642 __cpufreq_governor(data,
1648 /* might be a policy change, too, so fall through */
1650 dprintk("governor: change or update limits\n");
1651 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1655 cpufreq_debug_enable_ratelimit();
1660 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1661 * @cpu: CPU which shall be re-evaluated
1663 * Usefull for policy notifiers which have different necessities
1664 * at different times.
1666 int cpufreq_update_policy(unsigned int cpu)
1668 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1669 struct cpufreq_policy policy;
1675 if (unlikely(lock_policy_rwsem_write(cpu)))
1678 dprintk("updating policy for CPU %u\n", cpu);
1679 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1680 policy.min = data->user_policy.min;
1681 policy.max = data->user_policy.max;
1682 policy.policy = data->user_policy.policy;
1683 policy.governor = data->user_policy.governor;
1685 /* BIOS might change freq behind our back
1686 -> ask driver for current freq and notify governors about a change */
1687 if (cpufreq_driver->get) {
1688 policy.cur = cpufreq_driver->get(cpu);
1690 dprintk("Driver did not initialize current freq");
1691 data->cur = policy.cur;
1693 if (data->cur != policy.cur)
1694 cpufreq_out_of_sync(cpu, data->cur,
1699 ret = __cpufreq_set_policy(data, &policy);
1701 unlock_policy_rwsem_write(cpu);
1703 cpufreq_cpu_put(data);
1706 EXPORT_SYMBOL(cpufreq_update_policy);
1708 static int cpufreq_cpu_callback(struct notifier_block *nfb,
1709 unsigned long action, void *hcpu)
1711 unsigned int cpu = (unsigned long)hcpu;
1712 struct sys_device *sys_dev;
1714 sys_dev = get_cpu_sysdev(cpu);
1718 case CPU_ONLINE_FROZEN:
1719 cpufreq_add_dev(sys_dev);
1721 case CPU_DOWN_PREPARE:
1722 case CPU_DOWN_PREPARE_FROZEN:
1723 if (unlikely(lock_policy_rwsem_write(cpu)))
1726 __cpufreq_remove_dev(sys_dev);
1728 case CPU_DOWN_FAILED:
1729 case CPU_DOWN_FAILED_FROZEN:
1730 cpufreq_add_dev(sys_dev);
1737 static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
1739 .notifier_call = cpufreq_cpu_callback,
1742 /*********************************************************************
1743 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1744 *********************************************************************/
1747 * cpufreq_register_driver - register a CPU Frequency driver
1748 * @driver_data: A struct cpufreq_driver containing the values#
1749 * submitted by the CPU Frequency driver.
1751 * Registers a CPU Frequency driver to this core code. This code
1752 * returns zero on success, -EBUSY when another driver got here first
1753 * (and isn't unregistered in the meantime).
1756 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1758 unsigned long flags;
1761 if (!driver_data || !driver_data->verify || !driver_data->init ||
1762 ((!driver_data->setpolicy) && (!driver_data->target)))
1765 dprintk("trying to register driver %s\n", driver_data->name);
1767 if (driver_data->setpolicy)
1768 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1770 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1771 if (cpufreq_driver) {
1772 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1775 cpufreq_driver = driver_data;
1776 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1778 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1780 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1784 /* check for at least one working CPU */
1785 for (i=0; i<NR_CPUS; i++)
1786 if (cpufreq_cpu_data[i])
1789 /* if all ->init() calls failed, unregister */
1791 dprintk("no CPU initialized for driver %s\n",
1793 sysdev_driver_unregister(&cpu_sysdev_class,
1794 &cpufreq_sysdev_driver);
1796 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1797 cpufreq_driver = NULL;
1798 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1803 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1804 dprintk("driver %s up and running\n", driver_data->name);
1805 cpufreq_debug_enable_ratelimit();
1810 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1814 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1816 * Unregister the current CPUFreq driver. Only call this if you have
1817 * the right to do so, i.e. if you have succeeded in initialising before!
1818 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1819 * currently not initialised.
1821 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1823 unsigned long flags;
1825 cpufreq_debug_disable_ratelimit();
1827 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1828 cpufreq_debug_enable_ratelimit();
1832 dprintk("unregistering driver %s\n", driver->name);
1834 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1835 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1837 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1838 cpufreq_driver = NULL;
1839 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1843 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1845 static int __init cpufreq_core_init(void)
1849 for_each_possible_cpu(cpu) {
1850 per_cpu(policy_cpu, cpu) = -1;
1851 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1856 core_initcall(cpufreq_core_init);