blob: 109d62ccf6514fe5475154ed821c7cb6bbefcbdf [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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) ||
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700226 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 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 {
Dave Jones78ee9982005-05-31 19:03:43 -0700261 dprintk(KERN_WARNING "Warning: CPU frequency is %u, "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 "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;
Dmitry Torokhov70f28172005-04-29 01:27:34 -0500524 ret = fattr->show ? fattr->show(policy,buf) : -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 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;
Dmitry Torokhov70f28172005-04-29 01:27:34 -0500538 ret = fattr->store ? fattr->store(policy,buf,count) : -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 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)
Venkatesh Pallipadi8085e1f2005-08-25 13:14:06 -0700630 goto err_out_driver_exit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
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
Venkatesh Pallipadi8085e1f2005-08-25 13:14:06 -0700676err_out_driver_exit:
677 if (cpufreq_driver->exit)
678 cpufreq_driver->exit(policy);
679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680err_out:
681 kfree(policy);
682
683nomem_out:
684 module_put(cpufreq_driver->owner);
685 module_out:
686 cpufreq_debug_enable_ratelimit();
687 return ret;
688}
689
690
691/**
692 * cpufreq_remove_dev - remove a CPU device
693 *
694 * Removes the cpufreq interface for a CPU device.
695 */
696static int cpufreq_remove_dev (struct sys_device * sys_dev)
697{
698 unsigned int cpu = sys_dev->id;
699 unsigned long flags;
700 struct cpufreq_policy *data;
701#ifdef CONFIG_SMP
702 unsigned int j;
703#endif
704
705 cpufreq_debug_disable_ratelimit();
706 dprintk("unregistering CPU %u\n", cpu);
707
708 spin_lock_irqsave(&cpufreq_driver_lock, flags);
709 data = cpufreq_cpu_data[cpu];
710
711 if (!data) {
712 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
713 cpu_sys_devices[cpu] = NULL;
714 cpufreq_debug_enable_ratelimit();
715 return -EINVAL;
716 }
717 cpufreq_cpu_data[cpu] = NULL;
718
719
720#ifdef CONFIG_SMP
721 /* if this isn't the CPU which is the parent of the kobj, we
722 * only need to unlink, put and exit
723 */
724 if (unlikely(cpu != data->cpu)) {
725 dprintk("removing link\n");
726 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
727 sysfs_remove_link(&sys_dev->kobj, "cpufreq");
728 cpu_sys_devices[cpu] = NULL;
729 cpufreq_cpu_put(data);
730 cpufreq_debug_enable_ratelimit();
731 return 0;
732 }
733#endif
734
735 cpu_sys_devices[cpu] = NULL;
736
737 if (!kobject_get(&data->kobj)) {
738 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
739 cpufreq_debug_enable_ratelimit();
740 return -EFAULT;
741 }
742
743#ifdef CONFIG_SMP
744 /* if we have other CPUs still registered, we need to unlink them,
745 * or else wait_for_completion below will lock up. Clean the
746 * cpufreq_cpu_data[] while holding the lock, and remove the sysfs
747 * links afterwards.
748 */
749 if (unlikely(cpus_weight(data->cpus) > 1)) {
750 for_each_cpu_mask(j, data->cpus) {
751 if (j == cpu)
752 continue;
753 cpufreq_cpu_data[j] = NULL;
754 }
755 }
756
757 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
758
759 if (unlikely(cpus_weight(data->cpus) > 1)) {
760 for_each_cpu_mask(j, data->cpus) {
761 if (j == cpu)
762 continue;
763 dprintk("removing link for cpu %u\n", j);
764 sysfs_remove_link(&cpu_sys_devices[j]->kobj, "cpufreq");
765 cpufreq_cpu_put(data);
766 }
767 }
768#else
769 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
770#endif
771
772 down(&data->lock);
773 if (cpufreq_driver->target)
774 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
775 cpufreq_driver->target = NULL;
776 up(&data->lock);
777
778 kobject_unregister(&data->kobj);
779
780 kobject_put(&data->kobj);
781
782 /* we need to make sure that the underlying kobj is actually
783 * not referenced anymore by anybody before we proceed with
784 * unloading.
785 */
786 dprintk("waiting for dropping of refcount\n");
787 wait_for_completion(&data->kobj_unregister);
788 dprintk("wait complete\n");
789
790 if (cpufreq_driver->exit)
791 cpufreq_driver->exit(data);
792
793 kfree(data);
794
795 cpufreq_debug_enable_ratelimit();
796
797 return 0;
798}
799
800
801static void handle_update(void *data)
802{
803 unsigned int cpu = (unsigned int)(long)data;
804 dprintk("handle_update for cpu %u called\n", cpu);
805 cpufreq_update_policy(cpu);
806}
807
808/**
809 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
810 * @cpu: cpu number
811 * @old_freq: CPU frequency the kernel thinks the CPU runs at
812 * @new_freq: CPU frequency the CPU actually runs at
813 *
814 * We adjust to current frequency first, and need to clean up later. So either call
815 * to cpufreq_update_policy() or schedule handle_update()).
816 */
817static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq, unsigned int new_freq)
818{
819 struct cpufreq_freqs freqs;
820
Dave Jones78ee9982005-05-31 19:03:43 -0700821 dprintk(KERN_WARNING "Warning: CPU frequency out of sync: cpufreq and timing "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
823
824 freqs.cpu = cpu;
825 freqs.old = old_freq;
826 freqs.new = new_freq;
827 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
828 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
829}
830
831
832/**
833 * cpufreq_get - get the current CPU frequency (in kHz)
834 * @cpu: CPU number
835 *
836 * Get the CPU current (static) CPU frequency
837 */
838unsigned int cpufreq_get(unsigned int cpu)
839{
840 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
841 unsigned int ret = 0;
842
843 if (!policy)
844 return 0;
845
846 if (!cpufreq_driver->get)
847 goto out;
848
849 down(&policy->lock);
850
851 ret = cpufreq_driver->get(cpu);
852
853 if (ret && policy->cur && !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS))
854 {
855 /* verify no discrepancy between actual and saved value exists */
856 if (unlikely(ret != policy->cur)) {
857 cpufreq_out_of_sync(cpu, policy->cur, ret);
858 schedule_work(&policy->update);
859 }
860 }
861
862 up(&policy->lock);
863
864 out:
865 cpufreq_cpu_put(policy);
866
867 return (ret);
868}
869EXPORT_SYMBOL(cpufreq_get);
870
871
872/**
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700873 * cpufreq_suspend - let the low level driver prepare for suspend
874 */
875
Bernard Blackhame00d9962005-07-07 17:56:42 -0700876static int cpufreq_suspend(struct sys_device * sysdev, pm_message_t pmsg)
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700877{
878 int cpu = sysdev->id;
879 unsigned int ret = 0;
880 unsigned int cur_freq = 0;
881 struct cpufreq_policy *cpu_policy;
882
883 dprintk("resuming cpu %u\n", cpu);
884
885 if (!cpu_online(cpu))
886 return 0;
887
888 /* we may be lax here as interrupts are off. Nonetheless
889 * we need to grab the correct cpu policy, as to check
890 * whether we really run on this CPU.
891 */
892
893 cpu_policy = cpufreq_cpu_get(cpu);
894 if (!cpu_policy)
895 return -EINVAL;
896
897 /* only handle each CPU group once */
898 if (unlikely(cpu_policy->cpu != cpu)) {
899 cpufreq_cpu_put(cpu_policy);
900 return 0;
901 }
902
903 if (cpufreq_driver->suspend) {
Bernard Blackhame00d9962005-07-07 17:56:42 -0700904 ret = cpufreq_driver->suspend(cpu_policy, pmsg);
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700905 if (ret) {
906 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
907 "step on CPU %u\n", cpu_policy->cpu);
908 cpufreq_cpu_put(cpu_policy);
909 return ret;
910 }
911 }
912
913
914 if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
915 goto out;
916
917 if (cpufreq_driver->get)
918 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
919
920 if (!cur_freq || !cpu_policy->cur) {
921 printk(KERN_ERR "cpufreq: suspend failed to assert current "
922 "frequency is what timing core thinks it is.\n");
923 goto out;
924 }
925
926 if (unlikely(cur_freq != cpu_policy->cur)) {
927 struct cpufreq_freqs freqs;
928
929 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
Dave Jones78ee9982005-05-31 19:03:43 -0700930 dprintk(KERN_DEBUG "Warning: CPU frequency is %u, "
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700931 "cpufreq assumed %u kHz.\n",
932 cur_freq, cpu_policy->cur);
933
934 freqs.cpu = cpu;
935 freqs.old = cpu_policy->cur;
936 freqs.new = cur_freq;
937
938 notifier_call_chain(&cpufreq_transition_notifier_list,
939 CPUFREQ_SUSPENDCHANGE, &freqs);
940 adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
941
942 cpu_policy->cur = cur_freq;
943 }
944
945 out:
946 cpufreq_cpu_put(cpu_policy);
947 return 0;
948}
949
950/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 * cpufreq_resume - restore proper CPU frequency handling after resume
952 *
953 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
954 * 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -0700955 * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
956 * restored.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 */
958static int cpufreq_resume(struct sys_device * sysdev)
959{
960 int cpu = sysdev->id;
961 unsigned int ret = 0;
962 struct cpufreq_policy *cpu_policy;
963
964 dprintk("resuming cpu %u\n", cpu);
965
966 if (!cpu_online(cpu))
967 return 0;
968
969 /* we may be lax here as interrupts are off. Nonetheless
970 * we need to grab the correct cpu policy, as to check
971 * whether we really run on this CPU.
972 */
973
974 cpu_policy = cpufreq_cpu_get(cpu);
975 if (!cpu_policy)
976 return -EINVAL;
977
978 /* only handle each CPU group once */
979 if (unlikely(cpu_policy->cpu != cpu)) {
980 cpufreq_cpu_put(cpu_policy);
981 return 0;
982 }
983
984 if (cpufreq_driver->resume) {
985 ret = cpufreq_driver->resume(cpu_policy);
986 if (ret) {
987 printk(KERN_ERR "cpufreq: resume failed in ->resume "
988 "step on CPU %u\n", cpu_policy->cpu);
989 cpufreq_cpu_put(cpu_policy);
990 return ret;
991 }
992 }
993
994 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
995 unsigned int cur_freq = 0;
996
997 if (cpufreq_driver->get)
998 cur_freq = cpufreq_driver->get(cpu_policy->cpu);
999
1000 if (!cur_freq || !cpu_policy->cur) {
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -07001001 printk(KERN_ERR "cpufreq: resume failed to assert "
1002 "current frequency is what timing core "
1003 "thinks it is.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 goto out;
1005 }
1006
1007 if (unlikely(cur_freq != cpu_policy->cur)) {
1008 struct cpufreq_freqs freqs;
1009
Benjamin Herrenschmidtac09f692005-05-02 16:25:10 +10001010 if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
Dave Jones78ee9982005-05-31 19:03:43 -07001011 dprintk(KERN_WARNING "Warning: CPU frequency"
Benjamin Herrenschmidtac09f692005-05-02 16:25:10 +10001012 "is %u, cpufreq assumed %u kHz.\n",
1013 cur_freq, cpu_policy->cur);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 freqs.cpu = cpu;
1016 freqs.old = cpu_policy->cur;
1017 freqs.new = cur_freq;
1018
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -07001019 notifier_call_chain(&cpufreq_transition_notifier_list,
1020 CPUFREQ_RESUMECHANGE, &freqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
1022
1023 cpu_policy->cur = cur_freq;
1024 }
1025 }
1026
1027out:
1028 schedule_work(&cpu_policy->update);
1029 cpufreq_cpu_put(cpu_policy);
1030 return ret;
1031}
1032
1033static struct sysdev_driver cpufreq_sysdev_driver = {
1034 .add = cpufreq_add_dev,
1035 .remove = cpufreq_remove_dev,
Benjamin Herrenschmidt42d4dc32005-04-29 07:40:12 -07001036 .suspend = cpufreq_suspend,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 .resume = cpufreq_resume,
1038};
1039
1040
1041/*********************************************************************
1042 * NOTIFIER LISTS INTERFACE *
1043 *********************************************************************/
1044
1045/**
1046 * cpufreq_register_notifier - register a driver with cpufreq
1047 * @nb: notifier function to register
1048 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1049 *
1050 * Add a driver to one of two lists: either a list of drivers that
1051 * are notified about clock rate changes (once before and once after
1052 * the transition), or a list of drivers that are notified about
1053 * changes in cpufreq policy.
1054 *
1055 * This function may sleep, and has the same return conditions as
1056 * notifier_chain_register.
1057 */
1058int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1059{
1060 int ret;
1061
1062 down_write(&cpufreq_notifier_rwsem);
1063 switch (list) {
1064 case CPUFREQ_TRANSITION_NOTIFIER:
1065 ret = notifier_chain_register(&cpufreq_transition_notifier_list, nb);
1066 break;
1067 case CPUFREQ_POLICY_NOTIFIER:
1068 ret = notifier_chain_register(&cpufreq_policy_notifier_list, nb);
1069 break;
1070 default:
1071 ret = -EINVAL;
1072 }
1073 up_write(&cpufreq_notifier_rwsem);
1074
1075 return ret;
1076}
1077EXPORT_SYMBOL(cpufreq_register_notifier);
1078
1079
1080/**
1081 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1082 * @nb: notifier block to be unregistered
1083 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1084 *
1085 * Remove a driver from the CPU frequency notifier list.
1086 *
1087 * This function may sleep, and has the same return conditions as
1088 * notifier_chain_unregister.
1089 */
1090int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1091{
1092 int ret;
1093
1094 down_write(&cpufreq_notifier_rwsem);
1095 switch (list) {
1096 case CPUFREQ_TRANSITION_NOTIFIER:
1097 ret = notifier_chain_unregister(&cpufreq_transition_notifier_list, nb);
1098 break;
1099 case CPUFREQ_POLICY_NOTIFIER:
1100 ret = notifier_chain_unregister(&cpufreq_policy_notifier_list, nb);
1101 break;
1102 default:
1103 ret = -EINVAL;
1104 }
1105 up_write(&cpufreq_notifier_rwsem);
1106
1107 return ret;
1108}
1109EXPORT_SYMBOL(cpufreq_unregister_notifier);
1110
1111
1112/*********************************************************************
1113 * GOVERNORS *
1114 *********************************************************************/
1115
1116
1117int __cpufreq_driver_target(struct cpufreq_policy *policy,
1118 unsigned int target_freq,
1119 unsigned int relation)
1120{
1121 int retval = -EINVAL;
1122 lock_cpu_hotplug();
1123 dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1124 target_freq, relation);
1125 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1126 retval = cpufreq_driver->target(policy, target_freq, relation);
1127 unlock_cpu_hotplug();
1128 return retval;
1129}
1130EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1131
1132
1133int cpufreq_driver_target(struct cpufreq_policy *policy,
1134 unsigned int target_freq,
1135 unsigned int relation)
1136{
Dave Jonescc993ca2005-07-28 09:43:56 -07001137 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138
1139 policy = cpufreq_cpu_get(policy->cpu);
1140 if (!policy)
1141 return -EINVAL;
1142
1143 down(&policy->lock);
1144
1145 ret = __cpufreq_driver_target(policy, target_freq, relation);
1146
1147 up(&policy->lock);
1148
1149 cpufreq_cpu_put(policy);
1150
1151 return ret;
1152}
1153EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1154
1155
1156static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
1157{
Dave Jonescc993ca2005-07-28 09:43:56 -07001158 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159
1160 if (!try_module_get(policy->governor->owner))
1161 return -EINVAL;
1162
1163 dprintk("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event);
1164 ret = policy->governor->governor(policy, event);
1165
1166 /* we keep one module reference alive for each CPU governed by this CPU */
1167 if ((event != CPUFREQ_GOV_START) || ret)
1168 module_put(policy->governor->owner);
1169 if ((event == CPUFREQ_GOV_STOP) && !ret)
1170 module_put(policy->governor->owner);
1171
1172 return ret;
1173}
1174
1175
1176int cpufreq_governor(unsigned int cpu, unsigned int event)
1177{
1178 int ret = 0;
1179 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1180
1181 if (!policy)
1182 return -EINVAL;
1183
1184 down(&policy->lock);
1185 ret = __cpufreq_governor(policy, event);
1186 up(&policy->lock);
1187
1188 cpufreq_cpu_put(policy);
1189
1190 return ret;
1191}
1192EXPORT_SYMBOL_GPL(cpufreq_governor);
1193
1194
1195int cpufreq_register_governor(struct cpufreq_governor *governor)
1196{
1197 struct cpufreq_governor *t;
1198
1199 if (!governor)
1200 return -EINVAL;
1201
1202 down(&cpufreq_governor_sem);
1203
1204 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
1205 if (!strnicmp(governor->name,t->name,CPUFREQ_NAME_LEN)) {
1206 up(&cpufreq_governor_sem);
1207 return -EBUSY;
1208 }
1209 }
1210 list_add(&governor->governor_list, &cpufreq_governor_list);
1211
1212 up(&cpufreq_governor_sem);
1213
1214 return 0;
1215}
1216EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1217
1218
1219void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1220{
1221 if (!governor)
1222 return;
1223
1224 down(&cpufreq_governor_sem);
1225 list_del(&governor->governor_list);
1226 up(&cpufreq_governor_sem);
1227 return;
1228}
1229EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1230
1231
1232
1233/*********************************************************************
1234 * POLICY INTERFACE *
1235 *********************************************************************/
1236
1237/**
1238 * cpufreq_get_policy - get the current cpufreq_policy
1239 * @policy: struct cpufreq_policy into which the current cpufreq_policy is written
1240 *
1241 * Reads the current cpufreq policy.
1242 */
1243int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1244{
1245 struct cpufreq_policy *cpu_policy;
1246 if (!policy)
1247 return -EINVAL;
1248
1249 cpu_policy = cpufreq_cpu_get(cpu);
1250 if (!cpu_policy)
1251 return -EINVAL;
1252
1253 down(&cpu_policy->lock);
1254 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1255 up(&cpu_policy->lock);
1256
1257 cpufreq_cpu_put(cpu_policy);
1258
1259 return 0;
1260}
1261EXPORT_SYMBOL(cpufreq_get_policy);
1262
1263
1264static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
1265{
1266 int ret = 0;
1267
1268 cpufreq_debug_disable_ratelimit();
1269 dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1270 policy->min, policy->max);
1271
1272 memcpy(&policy->cpuinfo,
1273 &data->cpuinfo,
1274 sizeof(struct cpufreq_cpuinfo));
1275
1276 /* verify the cpu speed can be set within this limit */
1277 ret = cpufreq_driver->verify(policy);
1278 if (ret)
1279 goto error_out;
1280
1281 down_read(&cpufreq_notifier_rwsem);
1282
1283 /* adjust if necessary - all reasons */
1284 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_ADJUST,
1285 policy);
1286
1287 /* adjust if necessary - hardware incompatibility*/
1288 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_INCOMPATIBLE,
1289 policy);
1290
1291 /* verify the cpu speed can be set within this limit,
1292 which might be different to the first one */
1293 ret = cpufreq_driver->verify(policy);
1294 if (ret) {
1295 up_read(&cpufreq_notifier_rwsem);
1296 goto error_out;
1297 }
1298
1299 /* notification of the new policy */
1300 notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY,
1301 policy);
1302
1303 up_read(&cpufreq_notifier_rwsem);
1304
1305 data->min = policy->min;
1306 data->max = policy->max;
1307
1308 dprintk("new min and max freqs are %u - %u kHz\n", data->min, data->max);
1309
1310 if (cpufreq_driver->setpolicy) {
1311 data->policy = policy->policy;
1312 dprintk("setting range\n");
1313 ret = cpufreq_driver->setpolicy(policy);
1314 } else {
1315 if (policy->governor != data->governor) {
1316 /* save old, working values */
1317 struct cpufreq_governor *old_gov = data->governor;
1318
1319 dprintk("governor switch\n");
1320
1321 /* end old governor */
1322 if (data->governor)
1323 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1324
1325 /* start new governor */
1326 data->governor = policy->governor;
1327 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1328 /* new governor failed, so re-start old one */
1329 dprintk("starting governor %s failed\n", data->governor->name);
1330 if (old_gov) {
1331 data->governor = old_gov;
1332 __cpufreq_governor(data, CPUFREQ_GOV_START);
1333 }
1334 ret = -EINVAL;
1335 goto error_out;
1336 }
1337 /* might be a policy change, too, so fall through */
1338 }
1339 dprintk("governor: change or update limits\n");
1340 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1341 }
1342
1343 error_out:
1344 cpufreq_debug_enable_ratelimit();
1345 return ret;
1346}
1347
1348/**
1349 * cpufreq_set_policy - set a new CPUFreq policy
1350 * @policy: policy to be set.
1351 *
1352 * Sets a new CPU frequency and voltage scaling policy.
1353 */
1354int cpufreq_set_policy(struct cpufreq_policy *policy)
1355{
1356 int ret = 0;
1357 struct cpufreq_policy *data;
1358
1359 if (!policy)
1360 return -EINVAL;
1361
1362 data = cpufreq_cpu_get(policy->cpu);
1363 if (!data)
1364 return -EINVAL;
1365
1366 /* lock this CPU */
1367 down(&data->lock);
1368
1369 ret = __cpufreq_set_policy(data, policy);
1370 data->user_policy.min = data->min;
1371 data->user_policy.max = data->max;
1372 data->user_policy.policy = data->policy;
1373 data->user_policy.governor = data->governor;
1374
1375 up(&data->lock);
1376 cpufreq_cpu_put(data);
1377
1378 return ret;
1379}
1380EXPORT_SYMBOL(cpufreq_set_policy);
1381
1382
1383/**
1384 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1385 * @cpu: CPU which shall be re-evaluated
1386 *
1387 * Usefull for policy notifiers which have different necessities
1388 * at different times.
1389 */
1390int cpufreq_update_policy(unsigned int cpu)
1391{
1392 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1393 struct cpufreq_policy policy;
1394 int ret = 0;
1395
1396 if (!data)
1397 return -ENODEV;
1398
1399 down(&data->lock);
1400
1401 dprintk("updating policy for CPU %u\n", cpu);
1402 memcpy(&policy,
1403 data,
1404 sizeof(struct cpufreq_policy));
1405 policy.min = data->user_policy.min;
1406 policy.max = data->user_policy.max;
1407 policy.policy = data->user_policy.policy;
1408 policy.governor = data->user_policy.governor;
1409
1410 ret = __cpufreq_set_policy(data, &policy);
1411
1412 up(&data->lock);
1413
1414 cpufreq_cpu_put(data);
1415 return ret;
1416}
1417EXPORT_SYMBOL(cpufreq_update_policy);
1418
1419
1420/*********************************************************************
1421 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1422 *********************************************************************/
1423
1424/**
1425 * cpufreq_register_driver - register a CPU Frequency driver
1426 * @driver_data: A struct cpufreq_driver containing the values#
1427 * submitted by the CPU Frequency driver.
1428 *
1429 * Registers a CPU Frequency driver to this core code. This code
1430 * returns zero on success, -EBUSY when another driver got here first
1431 * (and isn't unregistered in the meantime).
1432 *
1433 */
1434int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1435{
1436 unsigned long flags;
1437 int ret;
1438
1439 if (!driver_data || !driver_data->verify || !driver_data->init ||
1440 ((!driver_data->setpolicy) && (!driver_data->target)))
1441 return -EINVAL;
1442
1443 dprintk("trying to register driver %s\n", driver_data->name);
1444
1445 if (driver_data->setpolicy)
1446 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1447
1448 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1449 if (cpufreq_driver) {
1450 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1451 return -EBUSY;
1452 }
1453 cpufreq_driver = driver_data;
1454 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1455
1456 ret = sysdev_driver_register(&cpu_sysdev_class,&cpufreq_sysdev_driver);
1457
1458 if ((!ret) && !(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1459 int i;
1460 ret = -ENODEV;
1461
1462 /* check for at least one working CPU */
1463 for (i=0; i<NR_CPUS; i++)
1464 if (cpufreq_cpu_data[i])
1465 ret = 0;
1466
1467 /* if all ->init() calls failed, unregister */
1468 if (ret) {
1469 dprintk("no CPU initialized for driver %s\n", driver_data->name);
1470 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1471
1472 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1473 cpufreq_driver = NULL;
1474 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1475 }
1476 }
1477
1478 if (!ret) {
1479 dprintk("driver %s up and running\n", driver_data->name);
1480 cpufreq_debug_enable_ratelimit();
1481 }
1482
1483 return (ret);
1484}
1485EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1486
1487
1488/**
1489 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1490 *
1491 * Unregister the current CPUFreq driver. Only call this if you have
1492 * the right to do so, i.e. if you have succeeded in initialising before!
1493 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1494 * currently not initialised.
1495 */
1496int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1497{
1498 unsigned long flags;
1499
1500 cpufreq_debug_disable_ratelimit();
1501
1502 if (!cpufreq_driver || (driver != cpufreq_driver)) {
1503 cpufreq_debug_enable_ratelimit();
1504 return -EINVAL;
1505 }
1506
1507 dprintk("unregistering driver %s\n", driver->name);
1508
1509 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1510
1511 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1512 cpufreq_driver = NULL;
1513 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1514
1515 return 0;
1516}
1517EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);