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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 * 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
11 *
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.
15 *
16 */
17
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>
31#include <linux/syscore_ops.h>
32
33#include <trace/events/power.h>
34
35/**
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.
39 */
40static struct cpufreq_driver *cpufreq_driver;
41static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42#ifdef CONFIG_HOTPLUG_CPU
43/* This one keeps track of the previously set governor of a removed CPU */
44static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
45#endif
46static DEFINE_SPINLOCK(cpufreq_driver_lock);
47
48/*
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
51 *
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.
58 *
59 * Additional rules:
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.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
66 */
67static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
68static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
69
70#define lock_policy_rwsem(mode, cpu) \
71static int lock_policy_rwsem_##mode \
72(int cpu) \
73{ \
74 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
75 BUG_ON(policy_cpu == -1); \
76 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
77 if (unlikely(!cpu_online(cpu))) { \
78 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
79 return -1; \
80 } \
81 \
82 return 0; \
83}
84
85lock_policy_rwsem(read, cpu);
86
87lock_policy_rwsem(write, cpu);
88
89static void unlock_policy_rwsem_read(int cpu)
90{
91 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
94}
95
96static void unlock_policy_rwsem_write(int cpu)
97{
98 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
99 BUG_ON(policy_cpu == -1);
100 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
101}
102
103
104/* internal prototypes */
105static int __cpufreq_governor(struct cpufreq_policy *policy,
106 unsigned int event);
107static unsigned int __cpufreq_get(unsigned int cpu);
108static void handle_update(struct work_struct *work);
109
110/**
111 * Two notifier lists: the "policy" list is involved in the
112 * validation process for a new CPU frequency policy; the
113 * "transition" list for kernel code that needs to handle
114 * changes to devices when the CPU clock speed changes.
115 * The mutex locks both lists.
116 */
117static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
118static struct srcu_notifier_head cpufreq_transition_notifier_list;
119
120static bool init_cpufreq_transition_notifier_list_called;
121static int __init init_cpufreq_transition_notifier_list(void)
122{
123 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
124 init_cpufreq_transition_notifier_list_called = true;
125 return 0;
126}
127pure_initcall(init_cpufreq_transition_notifier_list);
128
129static int off __read_mostly;
130int cpufreq_disabled(void)
131{
132 return off;
133}
134void disable_cpufreq(void)
135{
136 off = 1;
137}
138static LIST_HEAD(cpufreq_governor_list);
139static DEFINE_MUTEX(cpufreq_governor_mutex);
140
141struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
142{
143 struct cpufreq_policy *data;
144 unsigned long flags;
145
146 if (cpu >= nr_cpu_ids)
147 goto err_out;
148
149 /* get the cpufreq driver */
150 spin_lock_irqsave(&cpufreq_driver_lock, flags);
151
152 if (!cpufreq_driver)
153 goto err_out_unlock;
154
155 if (!try_module_get(cpufreq_driver->owner))
156 goto err_out_unlock;
157
158
159 /* get the CPU */
160 data = per_cpu(cpufreq_cpu_data, cpu);
161
162 if (!data)
163 goto err_out_put_module;
164
165 if (!kobject_get(&data->kobj))
166 goto err_out_put_module;
167
168 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
169 return data;
170
171err_out_put_module:
172 module_put(cpufreq_driver->owner);
173err_out_unlock:
174 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
175err_out:
176 return NULL;
177}
178EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
179
180
181void cpufreq_cpu_put(struct cpufreq_policy *data)
182{
183 kobject_put(&data->kobj);
184 module_put(cpufreq_driver->owner);
185}
186EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
187
188
189/*********************************************************************
190 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
191 *********************************************************************/
192
193/**
194 * adjust_jiffies - adjust the system "loops_per_jiffy"
195 *
196 * This function alters the system "loops_per_jiffy" for the clock
197 * speed change. Note that loops_per_jiffy cannot be updated on SMP
198 * systems as each CPU might be scaled differently. So, use the arch
199 * per-CPU loops_per_jiffy value wherever possible.
200 */
201#ifndef CONFIG_SMP
202static unsigned long l_p_j_ref;
203static unsigned int l_p_j_ref_freq;
204
205static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
206{
207 if (ci->flags & CPUFREQ_CONST_LOOPS)
208 return;
209
210 if (!l_p_j_ref_freq) {
211 l_p_j_ref = loops_per_jiffy;
212 l_p_j_ref_freq = ci->old;
213 pr_debug("saving %lu as reference value for loops_per_jiffy; "
214 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
215 }
216 if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
217 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
218 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
219 ci->new);
220 pr_debug("scaling loops_per_jiffy to %lu "
221 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
222 }
223}
224#else
225static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
226{
227 return;
228}
229#endif
230
231
232/**
233 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
234 * on frequency transition.
235 *
236 * This function calls the transition notifiers and the "adjust_jiffies"
237 * function. It is called twice on all CPU frequency changes that have
238 * external effects.
239 */
240void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
241{
242 struct cpufreq_policy *policy;
243
244 BUG_ON(irqs_disabled());
245
246 freqs->flags = cpufreq_driver->flags;
247 pr_debug("notification %u of frequency transition to %u kHz\n",
248 state, freqs->new);
249
250 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
251 switch (state) {
252
253 case CPUFREQ_PRECHANGE:
254 /* detect if the driver reported a value as "old frequency"
255 * which is not equal to what the cpufreq core thinks is
256 * "old frequency".
257 */
258 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
259 if ((policy) && (policy->cpu == freqs->cpu) &&
260 (policy->cur) && (policy->cur != freqs->old)) {
261 pr_debug("Warning: CPU frequency is"
262 " %u, cpufreq assumed %u kHz.\n",
263 freqs->old, policy->cur);
264 freqs->old = policy->cur;
265 }
266 }
267 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
268 CPUFREQ_PRECHANGE, freqs);
269 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
270 break;
271
272 case CPUFREQ_POSTCHANGE:
273 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
274 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
275 (unsigned long)freqs->cpu);
276 trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
277 trace_cpu_frequency(freqs->new, freqs->cpu);
278 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
279 CPUFREQ_POSTCHANGE, freqs);
280 if (likely(policy) && likely(policy->cpu == freqs->cpu))
281 policy->cur = freqs->new;
282 break;
283 }
284}
285EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
286
287
288
289/*********************************************************************
290 * SYSFS INTERFACE *
291 *********************************************************************/
292
293static struct cpufreq_governor *__find_governor(const char *str_governor)
294{
295 struct cpufreq_governor *t;
296
297 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
298 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
299 return t;
300
301 return NULL;
302}
303
304/**
305 * cpufreq_parse_governor - parse a governor string
306 */
307static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
308 struct cpufreq_governor **governor)
309{
310 int err = -EINVAL;
311
312 if (!cpufreq_driver)
313 goto out;
314
315 if (cpufreq_driver->setpolicy) {
316 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
317 *policy = CPUFREQ_POLICY_PERFORMANCE;
318 err = 0;
319 } else if (!strnicmp(str_governor, "powersave",
320 CPUFREQ_NAME_LEN)) {
321 *policy = CPUFREQ_POLICY_POWERSAVE;
322 err = 0;
323 }
324 } else if (cpufreq_driver->target) {
325 struct cpufreq_governor *t;
326
327 mutex_lock(&cpufreq_governor_mutex);
328
329 t = __find_governor(str_governor);
330
331 if (t == NULL) {
332 int ret;
333
334 mutex_unlock(&cpufreq_governor_mutex);
335 ret = request_module("cpufreq_%s", str_governor);
336 mutex_lock(&cpufreq_governor_mutex);
337
338 if (ret == 0)
339 t = __find_governor(str_governor);
340 }
341
342 if (t != NULL) {
343 *governor = t;
344 err = 0;
345 }
346
347 mutex_unlock(&cpufreq_governor_mutex);
348 }
349out:
350 return err;
351}
352
353
354/**
355 * cpufreq_per_cpu_attr_read() / show_##file_name() -
356 * print out cpufreq information
357 *
358 * Write out information from cpufreq_driver->policy[cpu]; object must be
359 * "unsigned int".
360 */
361
362#define show_one(file_name, object) \
363static ssize_t show_##file_name \
364(struct cpufreq_policy *policy, char *buf) \
365{ \
366 return sprintf(buf, "%u\n", policy->object); \
367}
368
369show_one(cpuinfo_min_freq, cpuinfo.min_freq);
370show_one(cpuinfo_max_freq, cpuinfo.max_freq);
371show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
372show_one(scaling_min_freq, min);
373show_one(scaling_max_freq, max);
374show_one(scaling_cur_freq, cur);
375
376static int __cpufreq_set_policy(struct cpufreq_policy *data,
377 struct cpufreq_policy *policy);
378
379/**
380 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
381 */
382#define store_one(file_name, object) \
383static ssize_t store_##file_name \
384(struct cpufreq_policy *policy, const char *buf, size_t count) \
385{ \
386 unsigned int ret = -EINVAL; \
387 struct cpufreq_policy new_policy; \
388 \
389 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
390 if (ret) \
391 return -EINVAL; \
392 \
393 ret = sscanf(buf, "%u", &new_policy.object); \
394 if (ret != 1) \
395 return -EINVAL; \
396 \
397 ret = __cpufreq_set_policy(policy, &new_policy); \
398 policy->user_policy.object = policy->object; \
399 \
400 return ret ? ret : count; \
401}
402
403store_one(scaling_min_freq, min);
404store_one(scaling_max_freq, max);
405
406/**
407 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
408 */
409static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
410 char *buf)
411{
412 unsigned int cur_freq = __cpufreq_get(policy->cpu);
413 if (!cur_freq)
414 return sprintf(buf, "<unknown>");
415 return sprintf(buf, "%u\n", cur_freq);
416}
417
418
419/**
420 * show_scaling_governor - show the current policy for the specified CPU
421 */
422static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
423{
424 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
425 return sprintf(buf, "powersave\n");
426 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
427 return sprintf(buf, "performance\n");
428 else if (policy->governor)
429 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
430 policy->governor->name);
431 return -EINVAL;
432}
433
434
435/**
436 * store_scaling_governor - store policy for the specified CPU
437 */
438static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
439 const char *buf, size_t count)
440{
441 unsigned int ret = -EINVAL;
442 char str_governor[16];
443 struct cpufreq_policy new_policy;
444
445 ret = cpufreq_get_policy(&new_policy, policy->cpu);
446 if (ret)
447 return ret;
448
449 ret = sscanf(buf, "%15s", str_governor);
450 if (ret != 1)
451 return -EINVAL;
452
453 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
454 &new_policy.governor))
455 return -EINVAL;
456
457 /* Do not use cpufreq_set_policy here or the user_policy.max
458 will be wrongly overridden */
459 ret = __cpufreq_set_policy(policy, &new_policy);
460
461 policy->user_policy.policy = policy->policy;
462 policy->user_policy.governor = policy->governor;
463
464 if (ret)
465 return ret;
466 else
467 return count;
468}
469
470/**
471 * show_scaling_driver - show the cpufreq driver currently loaded
472 */
473static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
474{
475 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
476}
477
478/**
479 * show_scaling_available_governors - show the available CPUfreq governors
480 */
481static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
482 char *buf)
483{
484 ssize_t i = 0;
485 struct cpufreq_governor *t;
486
487 if (!cpufreq_driver->target) {
488 i += sprintf(buf, "performance powersave");
489 goto out;
490 }
491
492 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
493 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
494 - (CPUFREQ_NAME_LEN + 2)))
495 goto out;
496 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
497 }
498out:
499 i += sprintf(&buf[i], "\n");
500 return i;
501}
502
503static ssize_t show_cpus(const struct cpumask *mask, char *buf)
504{
505 ssize_t i = 0;
506 unsigned int cpu;
507
508 for_each_cpu(cpu, mask) {
509 if (i)
510 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
511 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
512 if (i >= (PAGE_SIZE - 5))
513 break;
514 }
515 i += sprintf(&buf[i], "\n");
516 return i;
517}
518
519/**
520 * show_related_cpus - show the CPUs affected by each transition even if
521 * hw coordination is in use
522 */
523static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
524{
525 if (cpumask_empty(policy->related_cpus))
526 return show_cpus(policy->cpus, buf);
527 return show_cpus(policy->related_cpus, buf);
528}
529
530/**
531 * show_affected_cpus - show the CPUs affected by each transition
532 */
533static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
534{
535 return show_cpus(policy->cpus, buf);
536}
537
538static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
539 const char *buf, size_t count)
540{
541 unsigned int freq = 0;
542 unsigned int ret;
543
544 if (!policy->governor || !policy->governor->store_setspeed)
545 return -EINVAL;
546
547 ret = sscanf(buf, "%u", &freq);
548 if (ret != 1)
549 return -EINVAL;
550
551 policy->governor->store_setspeed(policy, freq);
552
553 return count;
554}
555
556static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
557{
558 if (!policy->governor || !policy->governor->show_setspeed)
559 return sprintf(buf, "<unsupported>\n");
560
561 return policy->governor->show_setspeed(policy, buf);
562}
563
564/**
565 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
566 */
567static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
568{
569 unsigned int limit;
570 int ret;
571 if (cpufreq_driver->bios_limit) {
572 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
573 if (!ret)
574 return sprintf(buf, "%u\n", limit);
575 }
576 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
577}
578
579cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
580cpufreq_freq_attr_ro(cpuinfo_min_freq);
581cpufreq_freq_attr_ro(cpuinfo_max_freq);
582cpufreq_freq_attr_ro(cpuinfo_transition_latency);
583cpufreq_freq_attr_ro(scaling_available_governors);
584cpufreq_freq_attr_ro(scaling_driver);
585cpufreq_freq_attr_ro(scaling_cur_freq);
586cpufreq_freq_attr_ro(bios_limit);
587cpufreq_freq_attr_ro(related_cpus);
588cpufreq_freq_attr_ro(affected_cpus);
589cpufreq_freq_attr_rw(scaling_min_freq);
590cpufreq_freq_attr_rw(scaling_max_freq);
591cpufreq_freq_attr_rw(scaling_governor);
592cpufreq_freq_attr_rw(scaling_setspeed);
593
594static struct attribute *default_attrs[] = {
595 &cpuinfo_min_freq.attr,
596 &cpuinfo_max_freq.attr,
597 &cpuinfo_transition_latency.attr,
598 &scaling_min_freq.attr,
599 &scaling_max_freq.attr,
600 &affected_cpus.attr,
601 &related_cpus.attr,
602 &scaling_governor.attr,
603 &scaling_driver.attr,
604 &scaling_available_governors.attr,
605 &scaling_setspeed.attr,
606 NULL
607};
608
609struct kobject *cpufreq_global_kobject;
610EXPORT_SYMBOL(cpufreq_global_kobject);
611
612#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
613#define to_attr(a) container_of(a, struct freq_attr, attr)
614
615static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
616{
617 struct cpufreq_policy *policy = to_policy(kobj);
618 struct freq_attr *fattr = to_attr(attr);
619 ssize_t ret = -EINVAL;
620 policy = cpufreq_cpu_get(policy->cpu);
621 if (!policy)
622 goto no_policy;
623
624 if (lock_policy_rwsem_read(policy->cpu) < 0)
625 goto fail;
626
627 if (fattr->show)
628 ret = fattr->show(policy, buf);
629 else
630 ret = -EIO;
631
632 unlock_policy_rwsem_read(policy->cpu);
633fail:
634 cpufreq_cpu_put(policy);
635no_policy:
636 return ret;
637}
638
639static ssize_t store(struct kobject *kobj, struct attribute *attr,
640 const char *buf, size_t count)
641{
642 struct cpufreq_policy *policy = to_policy(kobj);
643 struct freq_attr *fattr = to_attr(attr);
644 ssize_t ret = -EINVAL;
645 policy = cpufreq_cpu_get(policy->cpu);
646 if (!policy)
647 goto no_policy;
648
649 if (lock_policy_rwsem_write(policy->cpu) < 0)
650 goto fail;
651
652 if (fattr->store)
653 ret = fattr->store(policy, buf, count);
654 else
655 ret = -EIO;
656
657 unlock_policy_rwsem_write(policy->cpu);
658fail:
659 cpufreq_cpu_put(policy);
660no_policy:
661 return ret;
662}
663
664static void cpufreq_sysfs_release(struct kobject *kobj)
665{
666 struct cpufreq_policy *policy = to_policy(kobj);
667 pr_debug("last reference is dropped\n");
668 complete(&policy->kobj_unregister);
669}
670
671static const struct sysfs_ops sysfs_ops = {
672 .show = show,
673 .store = store,
674};
675
676static struct kobj_type ktype_cpufreq = {
677 .sysfs_ops = &sysfs_ops,
678 .default_attrs = default_attrs,
679 .release = cpufreq_sysfs_release,
680};
681
682/*
683 * Returns:
684 * Negative: Failure
685 * 0: Success
686 * Positive: When we have a managed CPU and the sysfs got symlinked
687 */
688static int cpufreq_add_dev_policy(unsigned int cpu,
689 struct cpufreq_policy *policy,
690 struct device *dev)
691{
692 int ret = 0;
693#ifdef CONFIG_SMP
694 unsigned long flags;
695 unsigned int j;
696#ifdef CONFIG_HOTPLUG_CPU
697 struct cpufreq_governor *gov;
698
699 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
700 if (gov) {
701 policy->governor = gov;
702 pr_debug("Restoring governor %s for cpu %d\n",
703 policy->governor->name, cpu);
704 }
705#endif
706
707 for_each_cpu(j, policy->cpus) {
708 struct cpufreq_policy *managed_policy;
709
710 if (cpu == j)
711 continue;
712
713 /* Check for existing affected CPUs.
714 * They may not be aware of it due to CPU Hotplug.
715 * cpufreq_cpu_put is called when the device is removed
716 * in __cpufreq_remove_dev()
717 */
718 managed_policy = cpufreq_cpu_get(j);
719 if (unlikely(managed_policy)) {
720
721 /* Set proper policy_cpu */
722 unlock_policy_rwsem_write(cpu);
723 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
724
725 if (lock_policy_rwsem_write(cpu) < 0) {
726 /* Should not go through policy unlock path */
727 if (cpufreq_driver->exit)
728 cpufreq_driver->exit(policy);
729 cpufreq_cpu_put(managed_policy);
730 return -EBUSY;
731 }
732
733 spin_lock_irqsave(&cpufreq_driver_lock, flags);
734 cpumask_copy(managed_policy->cpus, policy->cpus);
735 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
736 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
737
738 pr_debug("CPU already managed, adding link\n");
739 ret = sysfs_create_link(&dev->kobj,
740 &managed_policy->kobj,
741 "cpufreq");
742 if (ret)
743 cpufreq_cpu_put(managed_policy);
744 /*
745 * Success. We only needed to be added to the mask.
746 * Call driver->exit() because only the cpu parent of
747 * the kobj needed to call init().
748 */
749 if (cpufreq_driver->exit)
750 cpufreq_driver->exit(policy);
751
752 if (!ret)
753 return 1;
754 else
755 return ret;
756 }
757 }
758#endif
759 return ret;
760}
761
762
763/* symlink affected CPUs */
764static int cpufreq_add_dev_symlink(unsigned int cpu,
765 struct cpufreq_policy *policy)
766{
767 unsigned int j;
768 int ret = 0;
769
770 for_each_cpu(j, policy->cpus) {
771 struct cpufreq_policy *managed_policy;
772 struct device *cpu_dev;
773
774 if (j == cpu)
775 continue;
776 if (!cpu_online(j))
777 continue;
778
779 pr_debug("CPU %u already managed, adding link\n", j);
780 managed_policy = cpufreq_cpu_get(cpu);
781 cpu_dev = get_cpu_device(j);
782 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
783 "cpufreq");
784 if (ret) {
785 cpufreq_cpu_put(managed_policy);
786 return ret;
787 }
788 }
789 return ret;
790}
791
792static int cpufreq_add_dev_interface(unsigned int cpu,
793 struct cpufreq_policy *policy,
794 struct device *dev)
795{
796 struct cpufreq_policy new_policy;
797 struct freq_attr **drv_attr;
798 unsigned long flags;
799 int ret = 0;
800 unsigned int j;
801
802 /* prepare interface data */
803 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
804 &dev->kobj, "cpufreq");
805 if (ret)
806 return ret;
807
808 /* set up files for this cpu device */
809 drv_attr = cpufreq_driver->attr;
810 while ((drv_attr) && (*drv_attr)) {
811 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
812 if (ret)
813 goto err_out_kobj_put;
814 drv_attr++;
815 }
816 if (cpufreq_driver->get) {
817 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
818 if (ret)
819 goto err_out_kobj_put;
820 }
821 if (cpufreq_driver->target) {
822 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
823 if (ret)
824 goto err_out_kobj_put;
825 }
826 if (cpufreq_driver->bios_limit) {
827 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
828 if (ret)
829 goto err_out_kobj_put;
830 }
831
832 spin_lock_irqsave(&cpufreq_driver_lock, flags);
833 for_each_cpu(j, policy->cpus) {
834 if (!cpu_online(j))
835 continue;
836 per_cpu(cpufreq_cpu_data, j) = policy;
837 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
838 }
839 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
840
841 ret = cpufreq_add_dev_symlink(cpu, policy);
842 if (ret)
843 goto err_out_kobj_put;
844
845 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
846 /* assure that the starting sequence is run in __cpufreq_set_policy */
847 policy->governor = NULL;
848
849 /* set default policy */
850 ret = __cpufreq_set_policy(policy, &new_policy);
851 policy->user_policy.policy = policy->policy;
852 policy->user_policy.governor = policy->governor;
853
854 if (ret) {
855 pr_debug("setting policy failed\n");
856 if (cpufreq_driver->exit)
857 cpufreq_driver->exit(policy);
858 }
859 return ret;
860
861err_out_kobj_put:
862 kobject_put(&policy->kobj);
863 wait_for_completion(&policy->kobj_unregister);
864 return ret;
865}
866
867
868/**
869 * cpufreq_add_dev - add a CPU device
870 *
871 * Adds the cpufreq interface for a CPU device.
872 *
873 * The Oracle says: try running cpufreq registration/unregistration concurrently
874 * with with cpu hotplugging and all hell will break loose. Tried to clean this
875 * mess up, but more thorough testing is needed. - Mathieu
876 */
877static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
878{
879 unsigned int cpu = dev->id;
880 int ret = 0, found = 0;
881 struct cpufreq_policy *policy;
882 unsigned long flags;
883 unsigned int j;
884#ifdef CONFIG_HOTPLUG_CPU
885 int sibling;
886#endif
887
888 if (cpu_is_offline(cpu))
889 return 0;
890
891 pr_debug("adding CPU %u\n", cpu);
892
893#ifdef CONFIG_SMP
894 /* check whether a different CPU already registered this
895 * CPU because it is in the same boat. */
896 policy = cpufreq_cpu_get(cpu);
897 if (unlikely(policy)) {
898 cpufreq_cpu_put(policy);
899 return 0;
900 }
901#endif
902
903 if (!try_module_get(cpufreq_driver->owner)) {
904 ret = -EINVAL;
905 goto module_out;
906 }
907
908 ret = -ENOMEM;
909 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
910 if (!policy)
911 goto nomem_out;
912
913 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
914 goto err_free_policy;
915
916 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
917 goto err_free_cpumask;
918
919 policy->cpu = cpu;
920 cpumask_copy(policy->cpus, cpumask_of(cpu));
921
922 /* Initially set CPU itself as the policy_cpu */
923 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
924 ret = (lock_policy_rwsem_write(cpu) < 0);
925 WARN_ON(ret);
926
927 init_completion(&policy->kobj_unregister);
928 INIT_WORK(&policy->update, handle_update);
929
930 /* Set governor before ->init, so that driver could check it */
931#ifdef CONFIG_HOTPLUG_CPU
932 for_each_online_cpu(sibling) {
933 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
934 if (cp && cp->governor &&
935 (cpumask_test_cpu(cpu, cp->related_cpus))) {
936 policy->governor = cp->governor;
937 found = 1;
938 break;
939 }
940 }
941#endif
942 if (!found)
943 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
944 /* call driver. From then on the cpufreq must be able
945 * to accept all calls to ->verify and ->setpolicy for this CPU
946 */
947 ret = cpufreq_driver->init(policy);
948 if (ret) {
949 pr_debug("initialization failed\n");
950 goto err_unlock_policy;
951 }
952 policy->user_policy.min = policy->min;
953 policy->user_policy.max = policy->max;
954
955 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
956 CPUFREQ_START, policy);
957
958 ret = cpufreq_add_dev_policy(cpu, policy, dev);
959 if (ret) {
960 if (ret > 0)
961 /* This is a managed cpu, symlink created,
962 exit with 0 */
963 ret = 0;
964 goto err_unlock_policy;
965 }
966
967 ret = cpufreq_add_dev_interface(cpu, policy, dev);
968 if (ret)
969 goto err_out_unregister;
970
971 unlock_policy_rwsem_write(cpu);
972
973 kobject_uevent(&policy->kobj, KOBJ_ADD);
974 module_put(cpufreq_driver->owner);
975 pr_debug("initialization complete\n");
976
977 return 0;
978
979
980err_out_unregister:
981 spin_lock_irqsave(&cpufreq_driver_lock, flags);
982 for_each_cpu(j, policy->cpus)
983 per_cpu(cpufreq_cpu_data, j) = NULL;
984 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
985
986 kobject_put(&policy->kobj);
987 wait_for_completion(&policy->kobj_unregister);
988
989err_unlock_policy:
990 unlock_policy_rwsem_write(cpu);
991 free_cpumask_var(policy->related_cpus);
992err_free_cpumask:
993 free_cpumask_var(policy->cpus);
994err_free_policy:
995 kfree(policy);
996nomem_out:
997 module_put(cpufreq_driver->owner);
998module_out:
999 return ret;
1000}
1001
1002
1003/**
1004 * __cpufreq_remove_dev - remove a CPU device
1005 *
1006 * Removes the cpufreq interface for a CPU device.
1007 * Caller should already have policy_rwsem in write mode for this CPU.
1008 * This routine frees the rwsem before returning.
1009 */
1010static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1011{
1012 unsigned int cpu = dev->id;
1013 unsigned long flags;
1014 struct cpufreq_policy *data;
1015 struct kobject *kobj;
1016 struct completion *cmp;
1017#ifdef CONFIG_SMP
1018 struct device *cpu_dev;
1019 unsigned int j;
1020#endif
1021
1022 pr_debug("unregistering CPU %u\n", cpu);
1023
1024 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1025 data = per_cpu(cpufreq_cpu_data, cpu);
1026
1027 if (!data) {
1028 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1029 unlock_policy_rwsem_write(cpu);
1030 return -EINVAL;
1031 }
1032 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1033
1034
1035#ifdef CONFIG_SMP
1036 /* if this isn't the CPU which is the parent of the kobj, we
1037 * only need to unlink, put and exit
1038 */
1039 if (unlikely(cpu != data->cpu)) {
1040 pr_debug("removing link\n");
1041 cpumask_clear_cpu(cpu, data->cpus);
1042 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1043 kobj = &dev->kobj;
1044 cpufreq_cpu_put(data);
1045 unlock_policy_rwsem_write(cpu);
1046 sysfs_remove_link(kobj, "cpufreq");
1047 return 0;
1048 }
1049#endif
1050
1051#ifdef CONFIG_SMP
1052
1053#ifdef CONFIG_HOTPLUG_CPU
1054 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1055 CPUFREQ_NAME_LEN);
1056#endif
1057
1058 /* if we have other CPUs still registered, we need to unlink them,
1059 * or else wait_for_completion below will lock up. Clean the
1060 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1061 * the sysfs links afterwards.
1062 */
1063 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1064 for_each_cpu(j, data->cpus) {
1065 if (j == cpu)
1066 continue;
1067 per_cpu(cpufreq_cpu_data, j) = NULL;
1068 }
1069 }
1070
1071 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1072
1073 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1074 for_each_cpu(j, data->cpus) {
1075 if (j == cpu)
1076 continue;
1077 pr_debug("removing link for cpu %u\n", j);
1078#ifdef CONFIG_HOTPLUG_CPU
1079 strncpy(per_cpu(cpufreq_cpu_governor, j),
1080 data->governor->name, CPUFREQ_NAME_LEN);
1081#endif
1082 cpu_dev = get_cpu_device(j);
1083 kobj = &cpu_dev->kobj;
1084 unlock_policy_rwsem_write(cpu);
1085 sysfs_remove_link(kobj, "cpufreq");
1086 lock_policy_rwsem_write(cpu);
1087 cpufreq_cpu_put(data);
1088 }
1089 }
1090#else
1091 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1092#endif
1093
1094 if (cpufreq_driver->target)
1095 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1096
1097 kobj = &data->kobj;
1098 cmp = &data->kobj_unregister;
1099 unlock_policy_rwsem_write(cpu);
1100 kobject_put(kobj);
1101
1102 /* we need to make sure that the underlying kobj is actually
1103 * not referenced anymore by anybody before we proceed with
1104 * unloading.
1105 */
1106 pr_debug("waiting for dropping of refcount\n");
1107 wait_for_completion(cmp);
1108 pr_debug("wait complete\n");
1109
1110 lock_policy_rwsem_write(cpu);
1111 if (cpufreq_driver->exit)
1112 cpufreq_driver->exit(data);
1113 unlock_policy_rwsem_write(cpu);
1114
1115#ifdef CONFIG_HOTPLUG_CPU
1116 /* when the CPU which is the parent of the kobj is hotplugged
1117 * offline, check for siblings, and create cpufreq sysfs interface
1118 * and symlinks
1119 */
1120 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1121 /* first sibling now owns the new sysfs dir */
1122 cpumask_clear_cpu(cpu, data->cpus);
1123 cpufreq_add_dev(get_cpu_device(cpumask_first(data->cpus)), NULL);
1124
1125 /* finally remove our own symlink */
1126 lock_policy_rwsem_write(cpu);
1127 __cpufreq_remove_dev(dev, sif);
1128 }
1129#endif
1130
1131 free_cpumask_var(data->related_cpus);
1132 free_cpumask_var(data->cpus);
1133 kfree(data);
1134
1135 return 0;
1136}
1137
1138
1139static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1140{
1141 unsigned int cpu = dev->id;
1142 int retval;
1143
1144 if (cpu_is_offline(cpu))
1145 return 0;
1146
1147 if (unlikely(lock_policy_rwsem_write(cpu)))
1148 BUG();
1149
1150 retval = __cpufreq_remove_dev(dev, sif);
1151 return retval;
1152}
1153
1154
1155static void handle_update(struct work_struct *work)
1156{
1157 struct cpufreq_policy *policy =
1158 container_of(work, struct cpufreq_policy, update);
1159 unsigned int cpu = policy->cpu;
1160 pr_debug("handle_update for cpu %u called\n", cpu);
1161 cpufreq_update_policy(cpu);
1162}
1163
1164/**
1165 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1166 * @cpu: cpu number
1167 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1168 * @new_freq: CPU frequency the CPU actually runs at
1169 *
1170 * We adjust to current frequency first, and need to clean up later.
1171 * So either call to cpufreq_update_policy() or schedule handle_update()).
1172 */
1173static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1174 unsigned int new_freq)
1175{
1176 struct cpufreq_freqs freqs;
1177
1178 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1179 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1180
1181 freqs.cpu = cpu;
1182 freqs.old = old_freq;
1183 freqs.new = new_freq;
1184 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1185 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1186}
1187
1188
1189/**
1190 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1191 * @cpu: CPU number
1192 *
1193 * This is the last known freq, without actually getting it from the driver.
1194 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1195 */
1196unsigned int cpufreq_quick_get(unsigned int cpu)
1197{
1198 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1199 unsigned int ret_freq = 0;
1200
1201 if (policy) {
1202 ret_freq = policy->cur;
1203 cpufreq_cpu_put(policy);
1204 }
1205
1206 return ret_freq;
1207}
1208EXPORT_SYMBOL(cpufreq_quick_get);
1209
1210/**
1211 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1212 * @cpu: CPU number
1213 *
1214 * Just return the max possible frequency for a given CPU.
1215 */
1216unsigned int cpufreq_quick_get_max(unsigned int cpu)
1217{
1218 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1219 unsigned int ret_freq = 0;
1220
1221 if (policy) {
1222 ret_freq = policy->max;
1223 cpufreq_cpu_put(policy);
1224 }
1225
1226 return ret_freq;
1227}
1228EXPORT_SYMBOL(cpufreq_quick_get_max);
1229
1230
1231static unsigned int __cpufreq_get(unsigned int cpu)
1232{
1233 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1234 unsigned int ret_freq = 0;
1235
1236 if (!cpufreq_driver->get)
1237 return ret_freq;
1238
1239 ret_freq = cpufreq_driver->get(cpu);
1240
1241 if (ret_freq && policy->cur &&
1242 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1243 /* verify no discrepancy between actual and
1244 saved value exists */
1245 if (unlikely(ret_freq != policy->cur)) {
1246 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1247 schedule_work(&policy->update);
1248 }
1249 }
1250
1251 return ret_freq;
1252}
1253
1254/**
1255 * cpufreq_get - get the current CPU frequency (in kHz)
1256 * @cpu: CPU number
1257 *
1258 * Get the CPU current (static) CPU frequency
1259 */
1260unsigned int cpufreq_get(unsigned int cpu)
1261{
1262 unsigned int ret_freq = 0;
1263 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1264
1265 if (!policy)
1266 goto out;
1267
1268 if (unlikely(lock_policy_rwsem_read(cpu)))
1269 goto out_policy;
1270
1271 ret_freq = __cpufreq_get(cpu);
1272
1273 unlock_policy_rwsem_read(cpu);
1274
1275out_policy:
1276 cpufreq_cpu_put(policy);
1277out:
1278 return ret_freq;
1279}
1280EXPORT_SYMBOL(cpufreq_get);
1281
1282static struct subsys_interface cpufreq_interface = {
1283 .name = "cpufreq",
1284 .subsys = &cpu_subsys,
1285 .add_dev = cpufreq_add_dev,
1286 .remove_dev = cpufreq_remove_dev,
1287};
1288
1289
1290/**
1291 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1292 *
1293 * This function is only executed for the boot processor. The other CPUs
1294 * have been put offline by means of CPU hotplug.
1295 */
1296static int cpufreq_bp_suspend(void)
1297{
1298 int ret = 0;
1299
1300 int cpu = smp_processor_id();
1301 struct cpufreq_policy *cpu_policy;
1302
1303 pr_debug("suspending cpu %u\n", cpu);
1304
1305 /* If there's no policy for the boot CPU, we have nothing to do. */
1306 cpu_policy = cpufreq_cpu_get(cpu);
1307 if (!cpu_policy)
1308 return 0;
1309
1310 if (cpufreq_driver->suspend) {
1311 ret = cpufreq_driver->suspend(cpu_policy);
1312 if (ret)
1313 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1314 "step on CPU %u\n", cpu_policy->cpu);
1315 }
1316
1317 cpufreq_cpu_put(cpu_policy);
1318 return ret;
1319}
1320
1321/**
1322 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1323 *
1324 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1325 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1326 * restored. It will verify that the current freq is in sync with
1327 * what we believe it to be. This is a bit later than when it
1328 * should be, but nonethteless it's better than calling
1329 * cpufreq_driver->get() here which might re-enable interrupts...
1330 *
1331 * This function is only executed for the boot CPU. The other CPUs have not
1332 * been turned on yet.
1333 */
1334static void cpufreq_bp_resume(void)
1335{
1336 int ret = 0;
1337
1338 int cpu = smp_processor_id();
1339 struct cpufreq_policy *cpu_policy;
1340
1341 pr_debug("resuming cpu %u\n", cpu);
1342
1343 /* If there's no policy for the boot CPU, we have nothing to do. */
1344 cpu_policy = cpufreq_cpu_get(cpu);
1345 if (!cpu_policy)
1346 return;
1347
1348 if (cpufreq_driver->resume) {
1349 ret = cpufreq_driver->resume(cpu_policy);
1350 if (ret) {
1351 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1352 "step on CPU %u\n", cpu_policy->cpu);
1353 goto fail;
1354 }
1355 }
1356
1357 schedule_work(&cpu_policy->update);
1358
1359fail:
1360 cpufreq_cpu_put(cpu_policy);
1361}
1362
1363static struct syscore_ops cpufreq_syscore_ops = {
1364 .suspend = cpufreq_bp_suspend,
1365 .resume = cpufreq_bp_resume,
1366};
1367
1368
1369/*********************************************************************
1370 * NOTIFIER LISTS INTERFACE *
1371 *********************************************************************/
1372
1373/**
1374 * cpufreq_register_notifier - register a driver with cpufreq
1375 * @nb: notifier function to register
1376 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1377 *
1378 * Add a driver to one of two lists: either a list of drivers that
1379 * are notified about clock rate changes (once before and once after
1380 * the transition), or a list of drivers that are notified about
1381 * changes in cpufreq policy.
1382 *
1383 * This function may sleep, and has the same return conditions as
1384 * blocking_notifier_chain_register.
1385 */
1386int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1387{
1388 int ret;
1389
1390 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1391
1392 switch (list) {
1393 case CPUFREQ_TRANSITION_NOTIFIER:
1394 ret = srcu_notifier_chain_register(
1395 &cpufreq_transition_notifier_list, nb);
1396 break;
1397 case CPUFREQ_POLICY_NOTIFIER:
1398 ret = blocking_notifier_chain_register(
1399 &cpufreq_policy_notifier_list, nb);
1400 break;
1401 default:
1402 ret = -EINVAL;
1403 }
1404
1405 return ret;
1406}
1407EXPORT_SYMBOL(cpufreq_register_notifier);
1408
1409
1410/**
1411 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1412 * @nb: notifier block to be unregistered
1413 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1414 *
1415 * Remove a driver from the CPU frequency notifier list.
1416 *
1417 * This function may sleep, and has the same return conditions as
1418 * blocking_notifier_chain_unregister.
1419 */
1420int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1421{
1422 int ret;
1423
1424 switch (list) {
1425 case CPUFREQ_TRANSITION_NOTIFIER:
1426 ret = srcu_notifier_chain_unregister(
1427 &cpufreq_transition_notifier_list, nb);
1428 break;
1429 case CPUFREQ_POLICY_NOTIFIER:
1430 ret = blocking_notifier_chain_unregister(
1431 &cpufreq_policy_notifier_list, nb);
1432 break;
1433 default:
1434 ret = -EINVAL;
1435 }
1436
1437 return ret;
1438}
1439EXPORT_SYMBOL(cpufreq_unregister_notifier);
1440
1441
1442/*********************************************************************
1443 * GOVERNORS *
1444 *********************************************************************/
1445
1446
1447int __cpufreq_driver_target(struct cpufreq_policy *policy,
1448 unsigned int target_freq,
1449 unsigned int relation)
1450{
1451 int retval = -EINVAL;
1452
1453 if (cpufreq_disabled())
1454 return -ENODEV;
1455
1456 pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1457 target_freq, relation);
1458 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1459 retval = cpufreq_driver->target(policy, target_freq, relation);
1460
1461 return retval;
1462}
1463EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1464
1465int cpufreq_driver_target(struct cpufreq_policy *policy,
1466 unsigned int target_freq,
1467 unsigned int relation)
1468{
1469 int ret = -EINVAL;
1470
1471 policy = cpufreq_cpu_get(policy->cpu);
1472 if (!policy)
1473 goto no_policy;
1474
1475 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1476 goto fail;
1477
1478 ret = __cpufreq_driver_target(policy, target_freq, relation);
1479
1480 unlock_policy_rwsem_write(policy->cpu);
1481
1482fail:
1483 cpufreq_cpu_put(policy);
1484no_policy:
1485 return ret;
1486}
1487EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1488
1489int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1490{
1491 int ret = 0;
1492
1493 policy = cpufreq_cpu_get(policy->cpu);
1494 if (!policy)
1495 return -EINVAL;
1496
1497 if (cpu_online(cpu) && cpufreq_driver->getavg)
1498 ret = cpufreq_driver->getavg(policy, cpu);
1499
1500 cpufreq_cpu_put(policy);
1501 return ret;
1502}
1503EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1504
1505/*
1506 * when "event" is CPUFREQ_GOV_LIMITS
1507 */
1508
1509static int __cpufreq_governor(struct cpufreq_policy *policy,
1510 unsigned int event)
1511{
1512 int ret;
1513
1514 /* Only must be defined when default governor is known to have latency
1515 restrictions, like e.g. conservative or ondemand.
1516 That this is the case is already ensured in Kconfig
1517 */
1518#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1519 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1520#else
1521 struct cpufreq_governor *gov = NULL;
1522#endif
1523
1524 if (policy->governor->max_transition_latency &&
1525 policy->cpuinfo.transition_latency >
1526 policy->governor->max_transition_latency) {
1527 if (!gov)
1528 return -EINVAL;
1529 else {
1530 printk(KERN_WARNING "%s governor failed, too long"
1531 " transition latency of HW, fallback"
1532 " to %s governor\n",
1533 policy->governor->name,
1534 gov->name);
1535 policy->governor = gov;
1536 }
1537 }
1538
1539 if (!try_module_get(policy->governor->owner))
1540 return -EINVAL;
1541
1542 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1543 policy->cpu, event);
1544 ret = policy->governor->governor(policy, event);
1545
1546 /* we keep one module reference alive for
1547 each CPU governed by this CPU */
1548 if ((event != CPUFREQ_GOV_START) || ret)
1549 module_put(policy->governor->owner);
1550 if ((event == CPUFREQ_GOV_STOP) && !ret)
1551 module_put(policy->governor->owner);
1552
1553 return ret;
1554}
1555
1556
1557int cpufreq_register_governor(struct cpufreq_governor *governor)
1558{
1559 int err;
1560
1561 if (!governor)
1562 return -EINVAL;
1563
1564 if (cpufreq_disabled())
1565 return -ENODEV;
1566
1567 mutex_lock(&cpufreq_governor_mutex);
1568
1569 err = -EBUSY;
1570 if (__find_governor(governor->name) == NULL) {
1571 err = 0;
1572 list_add(&governor->governor_list, &cpufreq_governor_list);
1573 }
1574
1575 mutex_unlock(&cpufreq_governor_mutex);
1576 return err;
1577}
1578EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1579
1580
1581void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1582{
1583#ifdef CONFIG_HOTPLUG_CPU
1584 int cpu;
1585#endif
1586
1587 if (!governor)
1588 return;
1589
1590 if (cpufreq_disabled())
1591 return;
1592
1593#ifdef CONFIG_HOTPLUG_CPU
1594 for_each_present_cpu(cpu) {
1595 if (cpu_online(cpu))
1596 continue;
1597 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1598 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1599 }
1600#endif
1601
1602 mutex_lock(&cpufreq_governor_mutex);
1603 list_del(&governor->governor_list);
1604 mutex_unlock(&cpufreq_governor_mutex);
1605 return;
1606}
1607EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1608
1609
1610
1611/*********************************************************************
1612 * POLICY INTERFACE *
1613 *********************************************************************/
1614
1615/**
1616 * cpufreq_get_policy - get the current cpufreq_policy
1617 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1618 * is written
1619 *
1620 * Reads the current cpufreq policy.
1621 */
1622int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1623{
1624 struct cpufreq_policy *cpu_policy;
1625 if (!policy)
1626 return -EINVAL;
1627
1628 cpu_policy = cpufreq_cpu_get(cpu);
1629 if (!cpu_policy)
1630 return -EINVAL;
1631
1632 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1633
1634 cpufreq_cpu_put(cpu_policy);
1635 return 0;
1636}
1637EXPORT_SYMBOL(cpufreq_get_policy);
1638
1639
1640/*
1641 * data : current policy.
1642 * policy : policy to be set.
1643 */
1644static int __cpufreq_set_policy(struct cpufreq_policy *data,
1645 struct cpufreq_policy *policy)
1646{
1647 int ret = 0;
1648
1649 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1650 policy->min, policy->max);
1651
1652 memcpy(&policy->cpuinfo, &data->cpuinfo,
1653 sizeof(struct cpufreq_cpuinfo));
1654
1655 if (policy->min > data->max || policy->max < data->min) {
1656 ret = -EINVAL;
1657 goto error_out;
1658 }
1659
1660 /* verify the cpu speed can be set within this limit */
1661 ret = cpufreq_driver->verify(policy);
1662 if (ret)
1663 goto error_out;
1664
1665 /* adjust if necessary - all reasons */
1666 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1667 CPUFREQ_ADJUST, policy);
1668
1669 /* adjust if necessary - hardware incompatibility*/
1670 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1671 CPUFREQ_INCOMPATIBLE, policy);
1672
1673 /* verify the cpu speed can be set within this limit,
1674 which might be different to the first one */
1675 ret = cpufreq_driver->verify(policy);
1676 if (ret)
1677 goto error_out;
1678
1679 /* notification of the new policy */
1680 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1681 CPUFREQ_NOTIFY, policy);
1682
1683 data->min = policy->min;
1684 data->max = policy->max;
1685
1686 pr_debug("new min and max freqs are %u - %u kHz\n",
1687 data->min, data->max);
1688
1689 if (cpufreq_driver->setpolicy) {
1690 data->policy = policy->policy;
1691 pr_debug("setting range\n");
1692 ret = cpufreq_driver->setpolicy(policy);
1693 } else {
1694 if (policy->governor != data->governor) {
1695 /* save old, working values */
1696 struct cpufreq_governor *old_gov = data->governor;
1697
1698 pr_debug("governor switch\n");
1699
1700 /* end old governor */
1701 if (data->governor)
1702 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1703
1704 /* start new governor */
1705 data->governor = policy->governor;
1706 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1707 /* new governor failed, so re-start old one */
1708 pr_debug("starting governor %s failed\n",
1709 data->governor->name);
1710 if (old_gov) {
1711 data->governor = old_gov;
1712 __cpufreq_governor(data,
1713 CPUFREQ_GOV_START);
1714 }
1715 ret = -EINVAL;
1716 goto error_out;
1717 }
1718 /* might be a policy change, too, so fall through */
1719 }
1720 pr_debug("governor: change or update limits\n");
1721 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1722 }
1723
1724error_out:
1725 return ret;
1726}
1727
1728/**
1729 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1730 * @cpu: CPU which shall be re-evaluated
1731 *
1732 * Useful for policy notifiers which have different necessities
1733 * at different times.
1734 */
1735int cpufreq_update_policy(unsigned int cpu)
1736{
1737 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1738 struct cpufreq_policy policy;
1739 int ret;
1740
1741 if (!data) {
1742 ret = -ENODEV;
1743 goto no_policy;
1744 }
1745
1746 if (unlikely(lock_policy_rwsem_write(cpu))) {
1747 ret = -EINVAL;
1748 goto fail;
1749 }
1750
1751 pr_debug("updating policy for CPU %u\n", cpu);
1752 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1753 policy.min = data->user_policy.min;
1754 policy.max = data->user_policy.max;
1755 policy.policy = data->user_policy.policy;
1756 policy.governor = data->user_policy.governor;
1757
1758 /* BIOS might change freq behind our back
1759 -> ask driver for current freq and notify governors about a change */
1760 if (cpufreq_driver->get) {
1761 policy.cur = cpufreq_driver->get(cpu);
1762 if (!data->cur) {
1763 pr_debug("Driver did not initialize current freq");
1764 data->cur = policy.cur;
1765 } else {
1766 if (data->cur != policy.cur)
1767 cpufreq_out_of_sync(cpu, data->cur,
1768 policy.cur);
1769 }
1770 }
1771
1772 ret = __cpufreq_set_policy(data, &policy);
1773
1774 unlock_policy_rwsem_write(cpu);
1775
1776fail:
1777 cpufreq_cpu_put(data);
1778no_policy:
1779 return ret;
1780}
1781EXPORT_SYMBOL(cpufreq_update_policy);
1782
1783static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1784 unsigned long action, void *hcpu)
1785{
1786 unsigned int cpu = (unsigned long)hcpu;
1787 struct device *dev;
1788
1789 dev = get_cpu_device(cpu);
1790 if (dev) {
1791 switch (action) {
1792 case CPU_ONLINE:
1793 case CPU_ONLINE_FROZEN:
1794 cpufreq_add_dev(dev, NULL);
1795 break;
1796 case CPU_DOWN_PREPARE:
1797 case CPU_DOWN_PREPARE_FROZEN:
1798 if (unlikely(lock_policy_rwsem_write(cpu)))
1799 BUG();
1800
1801 __cpufreq_remove_dev(dev, NULL);
1802 break;
1803 case CPU_DOWN_FAILED:
1804 case CPU_DOWN_FAILED_FROZEN:
1805 cpufreq_add_dev(dev, NULL);
1806 break;
1807 }
1808 }
1809 return NOTIFY_OK;
1810}
1811
1812static struct notifier_block __refdata cpufreq_cpu_notifier = {
1813 .notifier_call = cpufreq_cpu_callback,
1814};
1815
1816/*********************************************************************
1817 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1818 *********************************************************************/
1819
1820/**
1821 * cpufreq_register_driver - register a CPU Frequency driver
1822 * @driver_data: A struct cpufreq_driver containing the values#
1823 * submitted by the CPU Frequency driver.
1824 *
1825 * Registers a CPU Frequency driver to this core code. This code
1826 * returns zero on success, -EBUSY when another driver got here first
1827 * (and isn't unregistered in the meantime).
1828 *
1829 */
1830int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1831{
1832 unsigned long flags;
1833 int ret;
1834
1835 if (cpufreq_disabled())
1836 return -ENODEV;
1837
1838 if (!driver_data || !driver_data->verify || !driver_data->init ||
1839 ((!driver_data->setpolicy) && (!driver_data->target)))
1840 return -EINVAL;
1841
1842 pr_debug("trying to register driver %s\n", driver_data->name);
1843
1844 if (driver_data->setpolicy)
1845 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1846
1847 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1848 if (cpufreq_driver) {
1849 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1850 return -EBUSY;
1851 }
1852 cpufreq_driver = driver_data;
1853 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1854
1855 ret = subsys_interface_register(&cpufreq_interface);
1856 if (ret)
1857 goto err_null_driver;
1858
1859 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1860 int i;
1861 ret = -ENODEV;
1862
1863 /* check for at least one working CPU */
1864 for (i = 0; i < nr_cpu_ids; i++)
1865 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1866 ret = 0;
1867 break;
1868 }
1869
1870 /* if all ->init() calls failed, unregister */
1871 if (ret) {
1872 pr_debug("no CPU initialized for driver %s\n",
1873 driver_data->name);
1874 goto err_if_unreg;
1875 }
1876 }
1877
1878 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1879 pr_debug("driver %s up and running\n", driver_data->name);
1880
1881 return 0;
1882err_if_unreg:
1883 subsys_interface_unregister(&cpufreq_interface);
1884err_null_driver:
1885 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1886 cpufreq_driver = NULL;
1887 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1888 return ret;
1889}
1890EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1891
1892
1893/**
1894 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1895 *
1896 * Unregister the current CPUFreq driver. Only call this if you have
1897 * the right to do so, i.e. if you have succeeded in initialising before!
1898 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1899 * currently not initialised.
1900 */
1901int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1902{
1903 unsigned long flags;
1904
1905 if (!cpufreq_driver || (driver != cpufreq_driver))
1906 return -EINVAL;
1907
1908 pr_debug("unregistering driver %s\n", driver->name);
1909
1910 subsys_interface_unregister(&cpufreq_interface);
1911 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1912
1913 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1914 cpufreq_driver = NULL;
1915 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1916
1917 return 0;
1918}
1919EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1920
1921static int __init cpufreq_core_init(void)
1922{
1923 int cpu;
1924
1925 if (cpufreq_disabled())
1926 return -ENODEV;
1927
1928 for_each_possible_cpu(cpu) {
1929 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1930 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1931 }
1932
1933 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
1934 BUG_ON(!cpufreq_global_kobject);
1935 register_syscore_ops(&cpufreq_syscore_ops);
1936
1937 return 0;
1938}
1939core_initcall(cpufreq_core_init);