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path: root/drivers/cpufreq/cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c1428
1 files changed, 1428 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
new file mode 100644
index 000000000000..b30001f31610
--- /dev/null
+++ b/drivers/cpufreq/cpufreq.c
@@ -0,0 +1,1428 @@
1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 */
12
13#include <linux/config.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/notifier.h>
18#include <linux/cpufreq.h>
19#include <linux/delay.h>
20#include <linux/interrupt.h>
21#include <linux/spinlock.h>
22#include <linux/device.h>
23#include <linux/slab.h>
24#include <linux/cpu.h>
25#include <linux/completion.h>
26
27#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, "cpufreq-core", msg)
28
29/**
30 * The "cpufreq driver" - the arch- or hardware-dependend low
31 * level driver of CPUFreq support, and its spinlock. This lock
32 * also protects the cpufreq_cpu_data array.
33 */
34static struct cpufreq_driver *cpufreq_driver;
35static struct cpufreq_policy *cpufreq_cpu_data[NR_CPUS];
36static DEFINE_SPINLOCK(cpufreq_driver_lock);
37
38
39/* we keep a copy of all ->add'ed CPU's struct sys_device here;
40 * as it is only accessed in ->add and ->remove, no lock or reference
41 * count is necessary.
42 */
43static struct sys_device *cpu_sys_devices[NR_CPUS];
44
45
46/* internal prototypes */
47static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
48static void handle_update(void *data);
49static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci);
50
51/**
52 * Two notifier lists: the "policy" list is involved in the
53 * validation process for a new CPU frequency policy; the
54 * "transition" list for kernel code that needs to handle
55 * changes to devices when the CPU clock speed changes.
56 * The mutex locks both lists.
57 */
58static struct notifier_block *cpufreq_policy_notifier_list;
59static struct notifier_block *cpufreq_transition_notifier_list;
60static DECLARE_RWSEM (cpufreq_notifier_rwsem);
61
62
63static LIST_HEAD(cpufreq_governor_list);
64static DECLARE_MUTEX (cpufreq_governor_sem);
65
66struct cpufreq_policy * cpufreq_cpu_get(unsigned int cpu)
67{
68 struct cpufreq_policy *data;
69 unsigned long flags;
70
71 if (cpu >= NR_CPUS)
72 goto err_out;
73
74 /* get the cpufreq driver */
75 spin_lock_irqsave(&cpufreq_driver_lock, flags);
76
77 if (!cpufreq_driver)
78 goto err_out_unlock;
79
80 if (!try_module_get(cpufreq_driver->owner))
81 goto err_out_unlock;
82
83
84 /* get the CPU */
85 data = cpufreq_cpu_data[cpu];
86
87 if (!data)
88 goto err_out_put_module;
89
90 if (!kobject_get(&data->kobj))
91 goto err_out_put_module;
92
93
94 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
95
96 return data;
97
98 err_out_put_module:
99 module_put(cpufreq_driver->owner);
100 err_out_unlock:
101 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
102 err_out:
103 return NULL;
104}
105EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
106
107void cpufreq_cpu_put(struct cpufreq_policy *data)
108{
109 kobject_put(&data->kobj);
110 module_put(cpufreq_driver->owner);
111}
112EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
113
114
115/*********************************************************************
116 * UNIFIED DEBUG HELPERS *
117 *********************************************************************/
118#ifdef CONFIG_CPU_FREQ_DEBUG
119
120/* what part(s) of the CPUfreq subsystem are debugged? */
121static unsigned int debug;
122
123/* is the debug output ratelimit'ed using printk_ratelimit? User can
124 * set or modify this value.
125 */
126static unsigned int debug_ratelimit = 1;
127
128/* is the printk_ratelimit'ing enabled? It's enabled after a successful
129 * loading of a cpufreq driver, temporarily disabled when a new policy
130 * is set, and disabled upon cpufreq driver removal
131 */
132static unsigned int disable_ratelimit = 1;
133static DEFINE_SPINLOCK(disable_ratelimit_lock);
134
135static inline void cpufreq_debug_enable_ratelimit(void)
136{
137 unsigned long flags;
138
139 spin_lock_irqsave(&disable_ratelimit_lock, flags);
140 if (disable_ratelimit)
141 disable_ratelimit--;
142 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
143}
144
145static inline void cpufreq_debug_disable_ratelimit(void)
146{
147 unsigned long flags;
148
149 spin_lock_irqsave(&disable_ratelimit_lock, flags);
150 disable_ratelimit++;
151 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
152}
153
154void cpufreq_debug_printk(unsigned int type, const char *prefix, const char *fmt, ...)
155{
156 char s[256];
157 va_list args;
158 unsigned int len;
159 unsigned long flags;
160
161 WARN_ON(!prefix);
162 if (type & debug) {
163 spin_lock_irqsave(&disable_ratelimit_lock, flags);
164 if (!disable_ratelimit && debug_ratelimit && !printk_ratelimit()) {
165 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
166 return;
167 }
168 spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
169
170 len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
171
172 va_start(args, fmt);
173 len += vsnprintf(&s[len], (256 - len), fmt, args);
174 va_end(args);
175
176 printk(s);
177
178 WARN_ON(len < 5);
179 }
180}
181EXPORT_SYMBOL(cpufreq_debug_printk);
182
183
184module_param(debug, uint, 0644);
185MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core, 2 to debug drivers, and 4 to debug governors.");
186
187module_param(debug_ratelimit, uint, 0644);
188MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging: set to 0 to disable ratelimiting.");
189
190#else /* !CONFIG_CPU_FREQ_DEBUG */
191
192static inline void cpufreq_debug_enable_ratelimit(void) { return; }
193static inline void cpufreq_debug_disable_ratelimit(void) { return; }
194
195#endif /* CONFIG_CPU_FREQ_DEBUG */
196
197
198/*********************************************************************
199 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
200 *********************************************************************/
201
202/**
203 * adjust_jiffies - adjust the system "loops_per_jiffy"
204 *
205 * This function alters the system "loops_per_jiffy" for the clock
206 * speed change. Note that loops_per_jiffy cannot be updated on SMP
207 * systems as each CPU might be scaled differently. So, use the arch
208 * per-CPU loops_per_jiffy value wherever possible.
209 */
210#ifndef CONFIG_SMP
211static unsigned long l_p_j_ref;
212static unsigned int l_p_j_ref_freq;
213
214static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
215{
216 if (ci->flags & CPUFREQ_CONST_LOOPS)
217 return;
218
219 if (!l_p_j_ref_freq) {
220 l_p_j_ref = loops_per_jiffy;
221 l_p_j_ref_freq = ci->old;
222 dprintk("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
223 }
224 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
225 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
226 (val == CPUFREQ_RESUMECHANGE)) {
227 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
228 dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
229 }
230}
231#else
232static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) { return; }
233#endif
234
235
236/**
237 * cpufreq_notify_transition - call notifier chain and adjust_jiffies on frequency transition
238 *
239 * This function calls the transition notifiers and the "adjust_jiffies" function. It is called
240 * twice on all CPU frequency changes that have external effects.
241 */
242void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
243{
244 BUG_ON(irqs_disabled());
245
246 freqs->flags = cpufreq_driver->flags;
247 dprintk("notification %u of frequency transition to %u kHz\n", state, freqs->new);
248
249 down_read(&cpufreq_notifier_rwsem);
250 switch (state) {
251 case CPUFREQ_PRECHANGE:
252 /* detect if the driver reported a value as "old frequency" which
253 * is not equal to what the cpufreq core thinks is "old frequency".
254 */
255 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
256 if ((likely(cpufreq_cpu_data[freqs->cpu])) &&
257 (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)) &&
258 (likely(cpufreq_cpu_data[freqs->cpu]->cur)) &&
259 (unlikely(freqs->old != cpufreq_cpu_data[freqs->cpu]->cur)))
260 {
261 printk(KERN_WARNING "Warning: CPU frequency is %u, "
262 "cpufreq assumed %u kHz.\n", freqs->old, cpufreq_cpu_data[freqs->cpu]->cur);
263 freqs->old = cpufreq_cpu_data[freqs->cpu]->cur;
264 }
265 }
266 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_PRECHANGE, freqs);
267 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
268 break;
269 case CPUFREQ_POSTCHANGE:
270 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
271 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_POSTCHANGE, freqs);
272 if ((likely(cpufreq_cpu_data[freqs->cpu])) &&
273 (likely(cpufreq_cpu_data[freqs->cpu]->cpu == freqs->cpu)))
274 cpufreq_cpu_data[freqs->cpu]->cur = freqs->new;
275 break;
276 }
277 up_read(&cpufreq_notifier_rwsem);
278}
279EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
280
281
282
283/*********************************************************************
284 * SYSFS INTERFACE *
285 *********************************************************************/
286
287/**
288 * cpufreq_parse_governor - parse a governor string
289 */
290static int cpufreq_parse_governor (char *str_governor, unsigned int *policy,
291 struct cpufreq_governor **governor)
292{
293 if (!cpufreq_driver)
294 return -EINVAL;
295 if (cpufreq_driver->setpolicy) {
296 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
297 *policy = CPUFREQ_POLICY_PERFORMANCE;
298 return 0;
299 } else if (!strnicmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
300 *policy = CPUFREQ_POLICY_POWERSAVE;
301 return 0;
302 }
303 return -EINVAL;
304 } else {
305 struct cpufreq_governor *t;
306 down(&cpufreq_governor_sem);
307 if (!cpufreq_driver || !cpufreq_driver->target)
308 goto out;
309 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
310 if (!strnicmp(str_governor,t->name,CPUFREQ_NAME_LEN)) {
311 *governor = t;
312 up(&cpufreq_governor_sem);
313 return 0;
314 }
315 }
316 out:
317 up(&cpufreq_governor_sem);
318 }
319 return -EINVAL;
320}
321EXPORT_SYMBOL_GPL(cpufreq_parse_governor);
322
323
324/* drivers/base/cpu.c */
325extern struct sysdev_class cpu_sysdev_class;
326
327
328/**
329 * cpufreq_per_cpu_attr_read() / show_##file_name() - print out cpufreq information
330 *
331 * Write out information from cpufreq_driver->policy[cpu]; object must be
332 * "unsigned int".
333 */
334
335#define show_one(file_name, object) \
336static ssize_t show_##file_name \
337(struct cpufreq_policy * policy, char *buf) \
338{ \
339 return sprintf (buf, "%u\n", policy->object); \
340}
341
342show_one(cpuinfo_min_freq, cpuinfo.min_freq);
343show_one(cpuinfo_max_freq, cpuinfo.max_freq);
344show_one(scaling_min_freq, min);
345show_one(scaling_max_freq, max);
346show_one(scaling_cur_freq, cur);
347
348/**
349 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
350 */
351#define store_one(file_name, object) \
352static ssize_t store_##file_name \
353(struct cpufreq_policy * policy, const char *buf, size_t count) \
354{ \
355 unsigned int ret = -EINVAL; \
356 struct cpufreq_policy new_policy; \
357 \
358 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
359 if (ret) \
360 return -EINVAL; \
361 \
362 ret = sscanf (buf, "%u", &new_policy.object); \
363 if (ret != 1) \
364 return -EINVAL; \
365 \
366 ret = cpufreq_set_policy(&new_policy); \
367 \
368 return ret ? ret : count; \
369}
370
371store_one(scaling_min_freq,min);
372store_one(scaling_max_freq,max);
373
374/**
375 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
376 */
377static ssize_t show_cpuinfo_cur_freq (struct cpufreq_policy * policy, char *buf)
378{
379 unsigned int cur_freq = cpufreq_get(policy->cpu);
380 if (!cur_freq)
381 return sprintf(buf, "<unknown>");
382 return sprintf(buf, "%u\n", cur_freq);
383}
384
385
386/**
387 * show_scaling_governor - show the current policy for the specified CPU
388 */
389static ssize_t show_scaling_governor (struct cpufreq_policy * policy, char *buf)
390{
391 if(policy->policy == CPUFREQ_POLICY_POWERSAVE)
392 return sprintf(buf, "powersave\n");
393 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
394 return sprintf(buf, "performance\n");
395 else if (policy->governor)
396 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", policy->governor->name);
397 return -EINVAL;
398}
399
400
401/**
402 * store_scaling_governor - store policy for the specified CPU
403 */
404static ssize_t store_scaling_governor (struct cpufreq_policy * policy,
405 const char *buf, size_t count)
406{
407 unsigned int ret = -EINVAL;
408 char str_governor[16];
409 struct cpufreq_policy new_policy;
410
411 ret = cpufreq_get_policy(&new_policy, policy->cpu);
412 if (ret)
413 return ret;
414
415 ret = sscanf (buf, "%15s", str_governor);
416 if (ret != 1)
417 return -EINVAL;
418
419 if (cpufreq_parse_governor(str_governor, &new_policy.policy, &new_policy.governor))
420 return -EINVAL;
421
422 ret = cpufreq_set_policy(&new_policy);
423
424 return ret ? ret : count;
425}
426
427/**
428 * show_scaling_driver - show the cpufreq driver currently loaded
429 */
430static ssize_t show_scaling_driver (struct cpufreq_policy * policy, char *buf)
431{
432 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
433}
434
435/**
436 * show_scaling_available_governors - show the available CPUfreq governors
437 */
438static ssize_t show_scaling_available_governors (struct cpufreq_policy * policy,
439 char *buf)
440{
441 ssize_t i = 0;
442 struct cpufreq_governor *t;
443
444 if (!cpufreq_driver->target) {
445 i += sprintf(buf, "performance powersave");
446 goto out;
447 }
448
449 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
450 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2)))
451 goto out;
452 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
453 }
454 out:
455 i += sprintf(&buf[i], "\n");
456 return i;
457}
458/**
459 * show_affected_cpus - show the CPUs affected by each transition
460 */
461static ssize_t show_affected_cpus (struct cpufreq_policy * policy, char *buf)
462{
463 ssize_t i = 0;
464 unsigned int cpu;
465
466 for_each_cpu_mask(cpu, policy->cpus) {
467 if (i)
468 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
469 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
470 if (i >= (PAGE_SIZE - 5))
471 break;
472 }
473 i += sprintf(&buf[i], "\n");
474 return i;
475}
476
477
478#define define_one_ro(_name) \
479static struct freq_attr _name = \
480__ATTR(_name, 0444, show_##_name, NULL)
481
482#define define_one_ro0400(_name) \
483static struct freq_attr _name = \
484__ATTR(_name, 0400, show_##_name, NULL)
485
486#define define_one_rw(_name) \
487static struct freq_attr _name = \
488__ATTR(_name, 0644, show_##_name, store_##_name)
489
490define_one_ro0400(cpuinfo_cur_freq);
491define_one_ro(cpuinfo_min_freq);
492define_one_ro(cpuinfo_max_freq);
493define_one_ro(scaling_available_governors);
494define_one_ro(scaling_driver);
495define_one_ro(scaling_cur_freq);
496define_one_ro(affected_cpus);
497define_one_rw(scaling_min_freq);
498define_one_rw(scaling_max_freq);
499define_one_rw(scaling_governor);
500
501static struct attribute * default_attrs[] = {
502 &cpuinfo_min_freq.attr,
503 &cpuinfo_max_freq.attr,
504 &scaling_min_freq.attr,
505 &scaling_max_freq.attr,
506 &affected_cpus.attr,
507 &scaling_governor.attr,
508 &scaling_driver.attr,
509 &scaling_available_governors.attr,
510 NULL
511};
512
513#define to_policy(k) container_of(k,struct cpufreq_policy,kobj)
514#define to_attr(a) container_of(a,struct freq_attr,attr)
515
516static ssize_t show(struct kobject * kobj, struct attribute * attr ,char * buf)
517{
518 struct cpufreq_policy * policy = to_policy(kobj);
519 struct freq_attr * fattr = to_attr(attr);
520 ssize_t ret;
521 policy = cpufreq_cpu_get(policy->cpu);
522 if (!policy)
523 return -EINVAL;
524 ret = fattr->show ? fattr->show(policy,buf) : 0;
525 cpufreq_cpu_put(policy);
526 return ret;
527}
528
529static ssize_t store(struct kobject * kobj, struct attribute * attr,
530 const char * buf, size_t count)
531{
532 struct cpufreq_policy * policy = to_policy(kobj);
533 struct freq_attr * fattr = to_attr(attr);
534 ssize_t ret;
535 policy = cpufreq_cpu_get(policy->cpu);
536 if (!policy)
537 return -EINVAL;
538 ret = fattr->store ? fattr->store(policy,buf,count) : 0;
539 cpufreq_cpu_put(policy);
540 return ret;
541}
542
543static void cpufreq_sysfs_release(struct kobject * kobj)
544{
545 struct cpufreq_policy * policy = to_policy(kobj);
546 dprintk("last reference is dropped\n");
547 complete(&policy->kobj_unregister);
548}
549
550static struct sysfs_ops sysfs_ops = {
551 .show = show,
552 .store = store,
553};
554
555static struct kobj_type ktype_cpufreq = {
556 .sysfs_ops = &sysfs_ops,
557 .default_attrs = default_attrs,
558 .release = cpufreq_sysfs_release,
559};
560
561
562/**
563 * cpufreq_add_dev - add a CPU device
564 *
565 * Adds the cpufreq interface for a CPU device.
566 */
567static int cpufreq_add_dev (struct sys_device * sys_dev)
568{
569 unsigned int cpu = sys_dev->id;
570 int ret = 0;
571 struct cpufreq_policy new_policy;
572 struct cpufreq_policy *policy;
573 struct freq_attr **drv_attr;
574 unsigned long flags;
575 unsigned int j;
576
577 cpufreq_debug_disable_ratelimit();
578 dprintk("adding CPU %u\n", cpu);
579
580#ifdef CONFIG_SMP
581 /* check whether a different CPU already registered this
582 * CPU because it is in the same boat. */
583 policy = cpufreq_cpu_get(cpu);
584 if (unlikely(policy)) {
585 cpu_sys_devices[cpu] = sys_dev;
586 dprintk("CPU already managed, adding link\n");
587 sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq");
588 cpufreq_debug_enable_ratelimit();
589 return 0;
590 }
591#endif
592
593 if (!try_module_get(cpufreq_driver->owner)) {
594 ret = -EINVAL;
595 goto module_out;
596 }
597
598 policy = kmalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
599 if (!policy) {
600 ret = -ENOMEM;
601 goto nomem_out;
602 }
603 memset(policy, 0, sizeof(struct cpufreq_policy));
604
605 policy->cpu = cpu;
606 policy->cpus = cpumask_of_cpu(cpu);
607
608 init_MUTEX_LOCKED(&policy->lock);
609 init_completion(&policy->kobj_unregister);
610 INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
611
612 /* call driver. From then on the cpufreq must be able
613 * to accept all calls to ->verify and ->setpolicy for this CPU
614 */
615 ret = cpufreq_driver->init(policy);
616 if (ret) {
617 dprintk("initialization failed\n");
618 goto err_out;
619 }
620
621 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
622
623 /* prepare interface data */
624 policy->kobj.parent = &sys_dev->kobj;
625 policy->kobj.ktype = &ktype_cpufreq;
626 strlcpy(policy->kobj.name, "cpufreq", KOBJ_NAME_LEN);
627
628 ret = kobject_register(&policy->kobj);
629 if (ret)
630 goto err_out;
631
632 /* set up files for this cpu device */
633 drv_attr = cpufreq_driver->attr;
634 while ((drv_attr) && (*drv_attr)) {
635 sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
636 drv_attr++;
637 }
638 if (cpufreq_driver->get)
639 sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
640 if (cpufreq_driver->target)
641 sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
642
643 spin_lock_irqsave(&cpufreq_driver_lock, flags);
644 for_each_cpu_mask(j, policy->cpus)
645 cpufreq_cpu_data[j] = policy;
646 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
647 policy->governor = NULL; /* to assure that the starting sequence is
648 * run in cpufreq_set_policy */
649 up(&policy->lock);
650
651 /* set default policy */
652
653 ret = cpufreq_set_policy(&new_policy);
654 if (ret) {
655 dprintk("setting policy failed\n");
656 goto err_out_unregister;
657 }
658
659 module_put(cpufreq_driver->owner);
660 cpu_sys_devices[cpu] = sys_dev;
661 dprintk("initialization complete\n");
662 cpufreq_debug_enable_ratelimit();
663
664 return 0;
665
666
667err_out_unregister:
668 spin_lock_irqsave(&cpufreq_driver_lock, flags);
669 for_each_cpu_mask(j, policy->cpus)
670 cpufreq_cpu_data[j] = NULL;
671 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
672
673 kobject_unregister(&policy->kobj);
674 wait_for_completion(&policy->kobj_unregister);
675
676err_out:
677 kfree(policy);
678
679nomem_out:
680 module_put(cpufreq_driver->owner);
681 module_out:
682 cpufreq_debug_enable_ratelimit();
683 return ret;
684}
685
686
687/**
688 * cpufreq_remove_dev - remove a CPU device
689 *
690 * Removes the cpufreq interface for a CPU device.
691 */
692static int cpufreq_remove_dev (struct sys_device * sys_dev)
693{
694 unsigned int cpu = sys_dev->id;
695 unsigned long flags;
696 struct cpufreq_policy *data;
697#ifdef CONFIG_SMP
698 unsigned int j;
699#endif
700
701 cpufreq_debug_disable_ratelimit();
702 dprintk("unregistering CPU %u\n", cpu);
703
704 spin_lock_irqsave(&cpufreq_driver_lock, flags);
705 data = cpufreq_cpu_data[cpu];
706
707 if (!data) {
708 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
709 cpu_sys_devices[cpu] = NULL;
710 cpufreq_debug_enable_ratelimit();
711 return -EINVAL;
712 }
713 cpufreq_cpu_data[cpu] = NULL;
714
715
716#ifdef CONFIG_SMP
717 /* if this isn't the CPU which is the parent of the kobj, we
718 * only need to unlink, put and exit
719 */
720 if (unlikely(cpu != data->cpu)) {
721 dprintk("removing link\n");
722 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
723 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
724 cpu_sys_devices[cpu] = NULL;
725 cpufreq_cpu_put(data);
726 cpufreq_debug_enable_ratelimit();
727 return 0;
728 }
729#endif
730
731 cpu_sys_devices[cpu] = NULL;
732
733 if (!kobject_get(&data->kobj)) {
734 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
735 cpufreq_debug_enable_ratelimit();
736 return -EFAULT;
737 }
738
739#ifdef CONFIG_SMP
740 /* if we have other CPUs still registered, we need to unlink them,
741 * or else wait_for_completion below will lock up. Clean the
742 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
743 * links afterwards.
744 */
745 if (unlikely(cpus_weight(data->cpus) > 1)) {
746 for_each_cpu_mask(j, data->cpus) {
747 if (j == cpu)
748 continue;
749 cpufreq_cpu_data[j] = NULL;
750 }
751 }
752
753 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
754
755 if (unlikely(cpus_weight(data->cpus) > 1)) {
756 for_each_cpu_mask(j, data->cpus) {
757 if (j == cpu)
758 continue;
759 dprintk("removing link for cpu %u\n", j);
760 sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
761 cpufreq_cpu_put(data);
762 }
763 }
764#else
765 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
766#endif
767
768 down(&data->lock);
769 if (cpufreq_driver->target)
770 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
771 cpufreq_driver->target = NULL;
772 up(&data->lock);
773
774 kobject_unregister(&data->kobj);
775
776 kobject_put(&data->kobj);
777
778 /* we need to make sure that the underlying kobj is actually
779 * not referenced anymore by anybody before we proceed with
780 * unloading.
781 */
782 dprintk("waiting for dropping of refcount\n");
783 wait_for_completion(&data->kobj_unregister);
784 dprintk("wait complete\n");
785
786 if (cpufreq_driver->exit)
787 cpufreq_driver->exit(data);
788
789 kfree(data);
790
791 cpufreq_debug_enable_ratelimit();
792
793 return 0;
794}
795
796
797static void handle_update(void *data)
798{
799 unsigned int cpu = (unsigned int)(long)data;
800 dprintk("handle_update for cpu %u called\n", cpu);
801 cpufreq_update_policy(cpu);
802}
803
804/**
805 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
806 * @cpu: cpu number
807 * @old_freq: CPU frequency the kernel thinks the CPU runs at
808 * @new_freq: CPU frequency the CPU actually runs at
809 *
810 * We adjust to current frequency first, and need to clean up later. So either call
811 * to cpufreq_update_policy() or schedule handle_update()).
812 */
813static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
814{
815 struct cpufreq_freqs freqs;
816
817 printk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
818 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
819
820 freqs.cpu = cpu;
821 freqs.old = old_freq;
822 freqs.new = new_freq;
823 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
824 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
825}
826
827
828/**
829 * cpufreq_get - get the current CPU frequency (in kHz)
830 * @cpu: CPU number
831 *
832 * Get the CPU current (static) CPU frequency
833 */
834unsigned int cpufreq_get(unsigned int cpu)
835{
836 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
837 unsigned int ret = 0;
838
839 if (!policy)
840 return 0;
841
842 if (!cpufreq_driver->get)
843 goto out;
844
845 down(&policy->lock);
846
847 ret = cpufreq_driver->get(cpu);
848
849 if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS))
850 {
851 /* verify no discrepancy between actual and saved value exists */
852 if (unlikely(ret != policy->cur)) {
853 cpufreq_out_of_sync(cpu, policy->cur, ret);
854 schedule_work(&policy->update);
855 }
856 }
857
858 up(&policy->lock);
859
860 out:
861 cpufreq_cpu_put(policy);
862
863 return (ret);
864}
865EXPORT_SYMBOL(cpufreq_get);
866
867
868/**
869 * cpufreq_resume - restore proper CPU frequency handling after resume
870 *
871 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
872 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
873 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are restored.
874 */
875static int cpufreq_resume(struct sys_device * sysdev)
876{
877 int cpu = sysdev->id;
878 unsigned int ret = 0;
879 struct cpufreq_policy *cpu_policy;
880
881 dprintk("resuming cpu %u\n", cpu);
882
883 if (!cpu_online(cpu))
884 return 0;
885
886 /* we may be lax here as interrupts are off. Nonetheless
887 * we need to grab the correct cpu policy, as to check
888 * whether we really run on this CPU.
889 */
890
891 cpu_policy = cpufreq_cpu_get(cpu);
892 if (!cpu_policy)
893 return -EINVAL;
894
895 /* only handle each CPU group once */
896 if (unlikely(cpu_policy->cpu != cpu)) {
897 cpufreq_cpu_put(cpu_policy);
898 return 0;
899 }
900
901 if (cpufreq_driver->resume) {
902 ret = cpufreq_driver->resume(cpu_policy);
903 if (ret) {
904 printk(KERN_ERR "cpufreq: resume failed in ->resume "
905 "step on CPU %u\n", cpu_policy->cpu);
906 cpufreq_cpu_put(cpu_policy);
907 return ret;
908 }
909 }
910
911 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
912 unsigned int cur_freq = 0;
913
914 if (cpufreq_driver->get)
915 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
916
917 if (!cur_freq || !cpu_policy->cur) {
918 printk(KERN_ERR "cpufreq: resume failed to assert current frequency is what timing core thinks it is.\n");
919 goto out;
920 }
921
922 if (unlikely(cur_freq != cpu_policy->cur)) {
923 struct cpufreq_freqs freqs;
924
925 printk(KERN_WARNING "Warning: CPU frequency is %u, "
926 "cpufreq assumed %u kHz.\n", cur_freq, cpu_policy->cur);
927
928 freqs.cpu = cpu;
929 freqs.old = cpu_policy->cur;
930 freqs.new = cur_freq;
931
932 notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_RESUMECHANGE, &freqs);
933 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
934
935 cpu_policy->cur = cur_freq;
936 }
937 }
938
939out:
940 schedule_work(&cpu_policy->update);
941 cpufreq_cpu_put(cpu_policy);
942 return ret;
943}
944
945static struct sysdev_driver cpufreq_sysdev_driver = {
946 .add = cpufreq_add_dev,
947 .remove = cpufreq_remove_dev,
948 .resume = cpufreq_resume,
949};
950
951
952/*********************************************************************
953 * NOTIFIER LISTS INTERFACE *
954 *********************************************************************/
955
956/**
957 * cpufreq_register_notifier - register a driver with cpufreq
958 * @nb: notifier function to register
959 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
960 *
961 * Add a driver to one of two lists: either a list of drivers that
962 * are notified about clock rate changes (once before and once after
963 * the transition), or a list of drivers that are notified about
964 * changes in cpufreq policy.
965 *
966 * This function may sleep, and has the same return conditions as
967 * notifier_chain_register.
968 */
969int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
970{
971 int ret;
972
973 down_write(&cpufreq_notifier_rwsem);
974 switch (list) {
975 case CPUFREQ_TRANSITION_NOTIFIER:
976 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
977 break;
978 case CPUFREQ_POLICY_NOTIFIER:
979 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
980 break;
981 default:
982 ret = -EINVAL;
983 }
984 up_write(&cpufreq_notifier_rwsem);
985
986 return ret;
987}
988EXPORT_SYMBOL(cpufreq_register_notifier);
989
990
991/**
992 * cpufreq_unregister_notifier - unregister a driver with cpufreq
993 * @nb: notifier block to be unregistered
994 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
995 *
996 * Remove a driver from the CPU frequency notifier list.
997 *
998 * This function may sleep, and has the same return conditions as
999 * notifier_chain_unregister.
1000 */
1001int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1002{
1003 int ret;
1004
1005 down_write(&cpufreq_notifier_rwsem);
1006 switch (list) {
1007 case CPUFREQ_TRANSITION_NOTIFIER:
1008 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1009 break;
1010 case CPUFREQ_POLICY_NOTIFIER:
1011 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1012 break;
1013 default:
1014 ret = -EINVAL;
1015 }
1016 up_write(&cpufreq_notifier_rwsem);
1017
1018 return ret;
1019}
1020EXPORT_SYMBOL(cpufreq_unregister_notifier);
1021
1022
1023/*********************************************************************
1024 * GOVERNORS *
1025 *********************************************************************/
1026
1027
1028int __cpufreq_driver_target(struct cpufreq_policy *policy,
1029 unsigned int target_freq,
1030 unsigned int relation)
1031{
1032 int retval = -EINVAL;
1033 lock_cpu_hotplug();
1034 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1035 target_freq, relation);
1036 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1037 retval = cpufreq_driver->target(policy, target_freq, relation);
1038 unlock_cpu_hotplug();
1039 return retval;
1040}
1041EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1042
1043
1044int cpufreq_driver_target(struct cpufreq_policy *policy,
1045 unsigned int target_freq,
1046 unsigned int relation)
1047{
1048 unsigned int ret;
1049
1050 policy = cpufreq_cpu_get(policy->cpu);
1051 if (!policy)
1052 return -EINVAL;
1053
1054 down(&policy->lock);
1055
1056 ret = __cpufreq_driver_target(policy, target_freq, relation);
1057
1058 up(&policy->lock);
1059
1060 cpufreq_cpu_put(policy);
1061
1062 return ret;
1063}
1064EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1065
1066
1067static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1068{
1069 int ret = -EINVAL;
1070
1071 if (!try_module_get(policy->governor->owner))
1072 return -EINVAL;
1073
1074 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1075 ret = policy->governor->governor(policy, event);
1076
1077 /* we keep one module reference alive for each CPU governed by this CPU */
1078 if ((event != CPUFREQ_GOV_START) || ret)
1079 module_put(policy->governor->owner);
1080 if ((event == CPUFREQ_GOV_STOP) && !ret)
1081 module_put(policy->governor->owner);
1082
1083 return ret;
1084}
1085
1086
1087int cpufreq_governor(unsigned int cpu, unsigned int event)
1088{
1089 int ret = 0;
1090 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1091
1092 if (!policy)
1093 return -EINVAL;
1094
1095 down(&policy->lock);
1096 ret = __cpufreq_governor(policy, event);
1097 up(&policy->lock);
1098
1099 cpufreq_cpu_put(policy);
1100
1101 return ret;
1102}
1103EXPORT_SYMBOL_GPL(cpufreq_governor);
1104
1105
1106int cpufreq_register_governor(struct cpufreq_governor *governor)
1107{
1108 struct cpufreq_governor *t;
1109
1110 if (!governor)
1111 return -EINVAL;
1112
1113 down(&cpufreq_governor_sem);
1114
1115 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1116 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1117 up(&cpufreq_governor_sem);
1118 return -EBUSY;
1119 }
1120 }
1121 list_add(&governor->governor_list, &cpufreq_governor_list);
1122
1123 up(&cpufreq_governor_sem);
1124
1125 return 0;
1126}
1127EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1128
1129
1130void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1131{
1132 if (!governor)
1133 return;
1134
1135 down(&cpufreq_governor_sem);
1136 list_del(&governor->governor_list);
1137 up(&cpufreq_governor_sem);
1138 return;
1139}
1140EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1141
1142
1143
1144/*********************************************************************
1145 * POLICY INTERFACE *
1146 *********************************************************************/
1147
1148/**
1149 * cpufreq_get_policy - get the current cpufreq_policy
1150 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1151 *
1152 * Reads the current cpufreq policy.
1153 */
1154int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1155{
1156 struct cpufreq_policy *cpu_policy;
1157 if (!policy)
1158 return -EINVAL;
1159
1160 cpu_policy = cpufreq_cpu_get(cpu);
1161 if (!cpu_policy)
1162 return -EINVAL;
1163
1164 down(&cpu_policy->lock);
1165 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1166 up(&cpu_policy->lock);
1167
1168 cpufreq_cpu_put(cpu_policy);
1169
1170 return 0;
1171}
1172EXPORT_SYMBOL(cpufreq_get_policy);
1173
1174
1175static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1176{
1177 int ret = 0;
1178
1179 cpufreq_debug_disable_ratelimit();
1180 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1181 policy->min, policy->max);
1182
1183 memcpy(&policy->cpuinfo,
1184 &data->cpuinfo,
1185 sizeof(struct cpufreq_cpuinfo));
1186
1187 /* verify the cpu speed can be set within this limit */
1188 ret = cpufreq_driver->verify(policy);
1189 if (ret)
1190 goto error_out;
1191
1192 down_read(&cpufreq_notifier_rwsem);
1193
1194 /* adjust if necessary - all reasons */
1195 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1196 policy);
1197
1198 /* adjust if necessary - hardware incompatibility*/
1199 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1200 policy);
1201
1202 /* verify the cpu speed can be set within this limit,
1203 which might be different to the first one */
1204 ret = cpufreq_driver->verify(policy);
1205 if (ret) {
1206 up_read(&cpufreq_notifier_rwsem);
1207 goto error_out;
1208 }
1209
1210 /* notification of the new policy */
1211 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1212 policy);
1213
1214 up_read(&cpufreq_notifier_rwsem);
1215
1216 data->min = policy->min;
1217 data->max = policy->max;
1218
1219 dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1220
1221 if (cpufreq_driver->setpolicy) {
1222 data->policy = policy->policy;
1223 dprintk("setting range\n");
1224 ret = cpufreq_driver->setpolicy(policy);
1225 } else {
1226 if (policy->governor != data->governor) {
1227 /* save old, working values */
1228 struct cpufreq_governor *old_gov = data->governor;
1229
1230 dprintk("governor switch\n");
1231
1232 /* end old governor */
1233 if (data->governor)
1234 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1235
1236 /* start new governor */
1237 data->governor = policy->governor;
1238 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1239 /* new governor failed, so re-start old one */
1240 dprintk("starting governor %s failed\n", data->governor->name);
1241 if (old_gov) {
1242 data->governor = old_gov;
1243 __cpufreq_governor(data, CPUFREQ_GOV_START);
1244 }
1245 ret = -EINVAL;
1246 goto error_out;
1247 }
1248 /* might be a policy change, too, so fall through */
1249 }
1250 dprintk("governor: change or update limits\n");
1251 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1252 }
1253
1254 error_out:
1255 cpufreq_debug_enable_ratelimit();
1256 return ret;
1257}
1258
1259/**
1260 * cpufreq_set_policy - set a new CPUFreq policy
1261 * @policy: policy to be set.
1262 *
1263 * Sets a new CPU frequency and voltage scaling policy.
1264 */
1265int cpufreq_set_policy(struct cpufreq_policy *policy)
1266{
1267 int ret = 0;
1268 struct cpufreq_policy *data;
1269
1270 if (!policy)
1271 return -EINVAL;
1272
1273 data = cpufreq_cpu_get(policy->cpu);
1274 if (!data)
1275 return -EINVAL;
1276
1277 /* lock this CPU */
1278 down(&data->lock);
1279
1280 ret = __cpufreq_set_policy(data, policy);
1281 data->user_policy.min = data->min;
1282 data->user_policy.max = data->max;
1283 data->user_policy.policy = data->policy;
1284 data->user_policy.governor = data->governor;
1285
1286 up(&data->lock);
1287 cpufreq_cpu_put(data);
1288
1289 return ret;
1290}
1291EXPORT_SYMBOL(cpufreq_set_policy);
1292
1293
1294/**
1295 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1296 * @cpu: CPU which shall be re-evaluated
1297 *
1298 * Usefull for policy notifiers which have different necessities
1299 * at different times.
1300 */
1301int cpufreq_update_policy(unsigned int cpu)
1302{
1303 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1304 struct cpufreq_policy policy;
1305 int ret = 0;
1306
1307 if (!data)
1308 return -ENODEV;
1309
1310 down(&data->lock);
1311
1312 dprintk("updating policy for CPU %u\n", cpu);
1313 memcpy(&policy,
1314 data,
1315 sizeof(struct cpufreq_policy));
1316 policy.min = data->user_policy.min;
1317 policy.max = data->user_policy.max;
1318 policy.policy = data->user_policy.policy;
1319 policy.governor = data->user_policy.governor;
1320
1321 ret = __cpufreq_set_policy(data, &policy);
1322
1323 up(&data->lock);
1324
1325 cpufreq_cpu_put(data);
1326 return ret;
1327}
1328EXPORT_SYMBOL(cpufreq_update_policy);
1329
1330
1331/*********************************************************************
1332 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1333 *********************************************************************/
1334
1335/**
1336 * cpufreq_register_driver - register a CPU Frequency driver
1337 * @driver_data: A struct cpufreq_driver containing the values#
1338 * submitted by the CPU Frequency driver.
1339 *
1340 * Registers a CPU Frequency driver to this core code. This code
1341 * returns zero on success, -EBUSY when another driver got here first
1342 * (and isn't unregistered in the meantime).
1343 *
1344 */
1345int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1346{
1347 unsigned long flags;
1348 int ret;
1349
1350 if (!driver_data || !driver_data->verify || !driver_data->init ||
1351 ((!driver_data->setpolicy) && (!driver_data->target)))
1352 return -EINVAL;
1353
1354 dprintk("trying to register driver %s\n", driver_data->name);
1355
1356 if (driver_data->setpolicy)
1357 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1358
1359 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1360 if (cpufreq_driver) {
1361 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1362 return -EBUSY;
1363 }
1364 cpufreq_driver = driver_data;
1365 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1366
1367 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1368
1369 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1370 int i;
1371 ret = -ENODEV;
1372
1373 /* check for at least one working CPU */
1374 for (i=0; i<NR_CPUS; i++)
1375 if (cpufreq_cpu_data[i])
1376 ret = 0;
1377
1378 /* if all ->init() calls failed, unregister */
1379 if (ret) {
1380 dprintk("no CPU initialized for driver %s\n", driver_data->name);
1381 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1382
1383 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1384 cpufreq_driver = NULL;
1385 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1386 }
1387 }
1388
1389 if (!ret) {
1390 dprintk("driver %s up and running\n", driver_data->name);
1391 cpufreq_debug_enable_ratelimit();
1392 }
1393
1394 return (ret);
1395}
1396EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1397
1398
1399/**
1400 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1401 *
1402 * Unregister the current CPUFreq driver. Only call this if you have
1403 * the right to do so, i.e. if you have succeeded in initialising before!
1404 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1405 * currently not initialised.
1406 */
1407int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1408{
1409 unsigned long flags;
1410
1411 cpufreq_debug_disable_ratelimit();
1412
1413 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1414 cpufreq_debug_enable_ratelimit();
1415 return -EINVAL;
1416 }
1417
1418 dprintk("unregistering driver %s\n", driver->name);
1419
1420 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1421
1422 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1423 cpufreq_driver = NULL;
1424 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1425
1426 return 0;
1427}
1428EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-12 06:51:03 -0500