Loading...
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 LIST_HEAD(cpufreq_governor_list);
130static DEFINE_MUTEX(cpufreq_governor_mutex);
131
132struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
133{
134 struct cpufreq_policy *data;
135 unsigned long flags;
136
137 if (cpu >= nr_cpu_ids)
138 goto err_out;
139
140 /* get the cpufreq driver */
141 spin_lock_irqsave(&cpufreq_driver_lock, flags);
142
143 if (!cpufreq_driver)
144 goto err_out_unlock;
145
146 if (!try_module_get(cpufreq_driver->owner))
147 goto err_out_unlock;
148
149
150 /* get the CPU */
151 data = per_cpu(cpufreq_cpu_data, cpu);
152
153 if (!data)
154 goto err_out_put_module;
155
156 if (!kobject_get(&data->kobj))
157 goto err_out_put_module;
158
159 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
160 return data;
161
162err_out_put_module:
163 module_put(cpufreq_driver->owner);
164err_out_unlock:
165 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
166err_out:
167 return NULL;
168}
169EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
170
171
172void cpufreq_cpu_put(struct cpufreq_policy *data)
173{
174 kobject_put(&data->kobj);
175 module_put(cpufreq_driver->owner);
176}
177EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
178
179
180/*********************************************************************
181 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
182 *********************************************************************/
183
184/**
185 * adjust_jiffies - adjust the system "loops_per_jiffy"
186 *
187 * This function alters the system "loops_per_jiffy" for the clock
188 * speed change. Note that loops_per_jiffy cannot be updated on SMP
189 * systems as each CPU might be scaled differently. So, use the arch
190 * per-CPU loops_per_jiffy value wherever possible.
191 */
192#ifndef CONFIG_SMP
193static unsigned long l_p_j_ref;
194static unsigned int l_p_j_ref_freq;
195
196static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
197{
198 if (ci->flags & CPUFREQ_CONST_LOOPS)
199 return;
200
201 if (!l_p_j_ref_freq) {
202 l_p_j_ref = loops_per_jiffy;
203 l_p_j_ref_freq = ci->old;
204 pr_debug("saving %lu as reference value for loops_per_jiffy; "
205 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
206 }
207 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
208 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
209 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
210 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
211 ci->new);
212 pr_debug("scaling loops_per_jiffy to %lu "
213 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
214 }
215}
216#else
217static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
218{
219 return;
220}
221#endif
222
223
224/**
225 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
226 * on frequency transition.
227 *
228 * This function calls the transition notifiers and the "adjust_jiffies"
229 * function. It is called twice on all CPU frequency changes that have
230 * external effects.
231 */
232void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
233{
234 struct cpufreq_policy *policy;
235
236 BUG_ON(irqs_disabled());
237
238 freqs->flags = cpufreq_driver->flags;
239 pr_debug("notification %u of frequency transition to %u kHz\n",
240 state, freqs->new);
241
242 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
243 switch (state) {
244
245 case CPUFREQ_PRECHANGE:
246 /* detect if the driver reported a value as "old frequency"
247 * which is not equal to what the cpufreq core thinks is
248 * "old frequency".
249 */
250 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
251 if ((policy) && (policy->cpu == freqs->cpu) &&
252 (policy->cur) && (policy->cur != freqs->old)) {
253 pr_debug("Warning: CPU frequency is"
254 " %u, cpufreq assumed %u kHz.\n",
255 freqs->old, policy->cur);
256 freqs->old = policy->cur;
257 }
258 }
259 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
260 CPUFREQ_PRECHANGE, freqs);
261 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
262 break;
263
264 case CPUFREQ_POSTCHANGE:
265 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
266 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
267 (unsigned long)freqs->cpu);
268 trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
269 trace_cpu_frequency(freqs->new, freqs->cpu);
270 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
271 CPUFREQ_POSTCHANGE, freqs);
272 if (likely(policy) && likely(policy->cpu == freqs->cpu))
273 policy->cur = freqs->new;
274 break;
275 }
276}
277EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
278
279
280
281/*********************************************************************
282 * SYSFS INTERFACE *
283 *********************************************************************/
284
285static struct cpufreq_governor *__find_governor(const char *str_governor)
286{
287 struct cpufreq_governor *t;
288
289 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
290 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
291 return t;
292
293 return NULL;
294}
295
296/**
297 * cpufreq_parse_governor - parse a governor string
298 */
299static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
300 struct cpufreq_governor **governor)
301{
302 int err = -EINVAL;
303
304 if (!cpufreq_driver)
305 goto out;
306
307 if (cpufreq_driver->setpolicy) {
308 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
309 *policy = CPUFREQ_POLICY_PERFORMANCE;
310 err = 0;
311 } else if (!strnicmp(str_governor, "powersave",
312 CPUFREQ_NAME_LEN)) {
313 *policy = CPUFREQ_POLICY_POWERSAVE;
314 err = 0;
315 }
316 } else if (cpufreq_driver->target) {
317 struct cpufreq_governor *t;
318
319 mutex_lock(&cpufreq_governor_mutex);
320
321 t = __find_governor(str_governor);
322
323 if (t == NULL) {
324 int ret;
325
326 mutex_unlock(&cpufreq_governor_mutex);
327 ret = request_module("cpufreq_%s", str_governor);
328 mutex_lock(&cpufreq_governor_mutex);
329
330 if (ret == 0)
331 t = __find_governor(str_governor);
332 }
333
334 if (t != NULL) {
335 *governor = t;
336 err = 0;
337 }
338
339 mutex_unlock(&cpufreq_governor_mutex);
340 }
341out:
342 return err;
343}
344
345
346/**
347 * cpufreq_per_cpu_attr_read() / show_##file_name() -
348 * print out cpufreq information
349 *
350 * Write out information from cpufreq_driver->policy[cpu]; object must be
351 * "unsigned int".
352 */
353
354#define show_one(file_name, object) \
355static ssize_t show_##file_name \
356(struct cpufreq_policy *policy, char *buf) \
357{ \
358 return sprintf(buf, "%u\n", policy->object); \
359}
360
361show_one(cpuinfo_min_freq, cpuinfo.min_freq);
362show_one(cpuinfo_max_freq, cpuinfo.max_freq);
363show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
364show_one(scaling_min_freq, min);
365show_one(scaling_max_freq, max);
366show_one(scaling_cur_freq, cur);
367
368static int __cpufreq_set_policy(struct cpufreq_policy *data,
369 struct cpufreq_policy *policy);
370
371/**
372 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
373 */
374#define store_one(file_name, object) \
375static ssize_t store_##file_name \
376(struct cpufreq_policy *policy, const char *buf, size_t count) \
377{ \
378 unsigned int ret = -EINVAL; \
379 struct cpufreq_policy new_policy; \
380 \
381 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
382 if (ret) \
383 return -EINVAL; \
384 \
385 ret = sscanf(buf, "%u", &new_policy.object); \
386 if (ret != 1) \
387 return -EINVAL; \
388 \
389 ret = __cpufreq_set_policy(policy, &new_policy); \
390 policy->user_policy.object = policy->object; \
391 \
392 return ret ? ret : count; \
393}
394
395store_one(scaling_min_freq, min);
396store_one(scaling_max_freq, max);
397
398/**
399 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
400 */
401static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
402 char *buf)
403{
404 unsigned int cur_freq = __cpufreq_get(policy->cpu);
405 if (!cur_freq)
406 return sprintf(buf, "<unknown>");
407 return sprintf(buf, "%u\n", cur_freq);
408}
409
410
411/**
412 * show_scaling_governor - show the current policy for the specified CPU
413 */
414static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
415{
416 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
417 return sprintf(buf, "powersave\n");
418 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
419 return sprintf(buf, "performance\n");
420 else if (policy->governor)
421 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
422 policy->governor->name);
423 return -EINVAL;
424}
425
426
427/**
428 * store_scaling_governor - store policy for the specified CPU
429 */
430static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
431 const char *buf, size_t count)
432{
433 unsigned int ret = -EINVAL;
434 char str_governor[16];
435 struct cpufreq_policy new_policy;
436
437 ret = cpufreq_get_policy(&new_policy, policy->cpu);
438 if (ret)
439 return ret;
440
441 ret = sscanf(buf, "%15s", str_governor);
442 if (ret != 1)
443 return -EINVAL;
444
445 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
446 &new_policy.governor))
447 return -EINVAL;
448
449 /* Do not use cpufreq_set_policy here or the user_policy.max
450 will be wrongly overridden */
451 ret = __cpufreq_set_policy(policy, &new_policy);
452
453 policy->user_policy.policy = policy->policy;
454 policy->user_policy.governor = policy->governor;
455
456 if (ret)
457 return ret;
458 else
459 return count;
460}
461
462/**
463 * show_scaling_driver - show the cpufreq driver currently loaded
464 */
465static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
466{
467 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
468}
469
470/**
471 * show_scaling_available_governors - show the available CPUfreq governors
472 */
473static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
474 char *buf)
475{
476 ssize_t i = 0;
477 struct cpufreq_governor *t;
478
479 if (!cpufreq_driver->target) {
480 i += sprintf(buf, "performance powersave");
481 goto out;
482 }
483
484 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
485 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
486 - (CPUFREQ_NAME_LEN + 2)))
487 goto out;
488 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
489 }
490out:
491 i += sprintf(&buf[i], "\n");
492 return i;
493}
494
495static ssize_t show_cpus(const struct cpumask *mask, char *buf)
496{
497 ssize_t i = 0;
498 unsigned int cpu;
499
500 for_each_cpu(cpu, mask) {
501 if (i)
502 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
503 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
504 if (i >= (PAGE_SIZE - 5))
505 break;
506 }
507 i += sprintf(&buf[i], "\n");
508 return i;
509}
510
511/**
512 * show_related_cpus - show the CPUs affected by each transition even if
513 * hw coordination is in use
514 */
515static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
516{
517 if (cpumask_empty(policy->related_cpus))
518 return show_cpus(policy->cpus, buf);
519 return show_cpus(policy->related_cpus, buf);
520}
521
522/**
523 * show_affected_cpus - show the CPUs affected by each transition
524 */
525static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
526{
527 return show_cpus(policy->cpus, buf);
528}
529
530static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
531 const char *buf, size_t count)
532{
533 unsigned int freq = 0;
534 unsigned int ret;
535
536 if (!policy->governor || !policy->governor->store_setspeed)
537 return -EINVAL;
538
539 ret = sscanf(buf, "%u", &freq);
540 if (ret != 1)
541 return -EINVAL;
542
543 policy->governor->store_setspeed(policy, freq);
544
545 return count;
546}
547
548static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
549{
550 if (!policy->governor || !policy->governor->show_setspeed)
551 return sprintf(buf, "<unsupported>\n");
552
553 return policy->governor->show_setspeed(policy, buf);
554}
555
556/**
557 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
558 */
559static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
560{
561 unsigned int limit;
562 int ret;
563 if (cpufreq_driver->bios_limit) {
564 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
565 if (!ret)
566 return sprintf(buf, "%u\n", limit);
567 }
568 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
569}
570
571cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
572cpufreq_freq_attr_ro(cpuinfo_min_freq);
573cpufreq_freq_attr_ro(cpuinfo_max_freq);
574cpufreq_freq_attr_ro(cpuinfo_transition_latency);
575cpufreq_freq_attr_ro(scaling_available_governors);
576cpufreq_freq_attr_ro(scaling_driver);
577cpufreq_freq_attr_ro(scaling_cur_freq);
578cpufreq_freq_attr_ro(bios_limit);
579cpufreq_freq_attr_ro(related_cpus);
580cpufreq_freq_attr_ro(affected_cpus);
581cpufreq_freq_attr_rw(scaling_min_freq);
582cpufreq_freq_attr_rw(scaling_max_freq);
583cpufreq_freq_attr_rw(scaling_governor);
584cpufreq_freq_attr_rw(scaling_setspeed);
585
586static struct attribute *default_attrs[] = {
587 &cpuinfo_min_freq.attr,
588 &cpuinfo_max_freq.attr,
589 &cpuinfo_transition_latency.attr,
590 &scaling_min_freq.attr,
591 &scaling_max_freq.attr,
592 &affected_cpus.attr,
593 &related_cpus.attr,
594 &scaling_governor.attr,
595 &scaling_driver.attr,
596 &scaling_available_governors.attr,
597 &scaling_setspeed.attr,
598 NULL
599};
600
601struct kobject *cpufreq_global_kobject;
602EXPORT_SYMBOL(cpufreq_global_kobject);
603
604#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
605#define to_attr(a) container_of(a, struct freq_attr, attr)
606
607static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
608{
609 struct cpufreq_policy *policy = to_policy(kobj);
610 struct freq_attr *fattr = to_attr(attr);
611 ssize_t ret = -EINVAL;
612 policy = cpufreq_cpu_get(policy->cpu);
613 if (!policy)
614 goto no_policy;
615
616 if (lock_policy_rwsem_read(policy->cpu) < 0)
617 goto fail;
618
619 if (fattr->show)
620 ret = fattr->show(policy, buf);
621 else
622 ret = -EIO;
623
624 unlock_policy_rwsem_read(policy->cpu);
625fail:
626 cpufreq_cpu_put(policy);
627no_policy:
628 return ret;
629}
630
631static ssize_t store(struct kobject *kobj, struct attribute *attr,
632 const char *buf, size_t count)
633{
634 struct cpufreq_policy *policy = to_policy(kobj);
635 struct freq_attr *fattr = to_attr(attr);
636 ssize_t ret = -EINVAL;
637 policy = cpufreq_cpu_get(policy->cpu);
638 if (!policy)
639 goto no_policy;
640
641 if (lock_policy_rwsem_write(policy->cpu) < 0)
642 goto fail;
643
644 if (fattr->store)
645 ret = fattr->store(policy, buf, count);
646 else
647 ret = -EIO;
648
649 unlock_policy_rwsem_write(policy->cpu);
650fail:
651 cpufreq_cpu_put(policy);
652no_policy:
653 return ret;
654}
655
656static void cpufreq_sysfs_release(struct kobject *kobj)
657{
658 struct cpufreq_policy *policy = to_policy(kobj);
659 pr_debug("last reference is dropped\n");
660 complete(&policy->kobj_unregister);
661}
662
663static const struct sysfs_ops sysfs_ops = {
664 .show = show,
665 .store = store,
666};
667
668static struct kobj_type ktype_cpufreq = {
669 .sysfs_ops = &sysfs_ops,
670 .default_attrs = default_attrs,
671 .release = cpufreq_sysfs_release,
672};
673
674/*
675 * Returns:
676 * Negative: Failure
677 * 0: Success
678 * Positive: When we have a managed CPU and the sysfs got symlinked
679 */
680static int cpufreq_add_dev_policy(unsigned int cpu,
681 struct cpufreq_policy *policy,
682 struct sys_device *sys_dev)
683{
684 int ret = 0;
685#ifdef CONFIG_SMP
686 unsigned long flags;
687 unsigned int j;
688#ifdef CONFIG_HOTPLUG_CPU
689 struct cpufreq_governor *gov;
690
691 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
692 if (gov) {
693 policy->governor = gov;
694 pr_debug("Restoring governor %s for cpu %d\n",
695 policy->governor->name, cpu);
696 }
697#endif
698
699 for_each_cpu(j, policy->cpus) {
700 struct cpufreq_policy *managed_policy;
701
702 if (cpu == j)
703 continue;
704
705 /* Check for existing affected CPUs.
706 * They may not be aware of it due to CPU Hotplug.
707 * cpufreq_cpu_put is called when the device is removed
708 * in __cpufreq_remove_dev()
709 */
710 managed_policy = cpufreq_cpu_get(j);
711 if (unlikely(managed_policy)) {
712
713 /* Set proper policy_cpu */
714 unlock_policy_rwsem_write(cpu);
715 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
716
717 if (lock_policy_rwsem_write(cpu) < 0) {
718 /* Should not go through policy unlock path */
719 if (cpufreq_driver->exit)
720 cpufreq_driver->exit(policy);
721 cpufreq_cpu_put(managed_policy);
722 return -EBUSY;
723 }
724
725 spin_lock_irqsave(&cpufreq_driver_lock, flags);
726 cpumask_copy(managed_policy->cpus, policy->cpus);
727 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
728 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
729
730 pr_debug("CPU already managed, adding link\n");
731 ret = sysfs_create_link(&sys_dev->kobj,
732 &managed_policy->kobj,
733 "cpufreq");
734 if (ret)
735 cpufreq_cpu_put(managed_policy);
736 /*
737 * Success. We only needed to be added to the mask.
738 * Call driver->exit() because only the cpu parent of
739 * the kobj needed to call init().
740 */
741 if (cpufreq_driver->exit)
742 cpufreq_driver->exit(policy);
743
744 if (!ret)
745 return 1;
746 else
747 return ret;
748 }
749 }
750#endif
751 return ret;
752}
753
754
755/* symlink affected CPUs */
756static int cpufreq_add_dev_symlink(unsigned int cpu,
757 struct cpufreq_policy *policy)
758{
759 unsigned int j;
760 int ret = 0;
761
762 for_each_cpu(j, policy->cpus) {
763 struct cpufreq_policy *managed_policy;
764 struct sys_device *cpu_sys_dev;
765
766 if (j == cpu)
767 continue;
768 if (!cpu_online(j))
769 continue;
770
771 pr_debug("CPU %u already managed, adding link\n", j);
772 managed_policy = cpufreq_cpu_get(cpu);
773 cpu_sys_dev = get_cpu_sysdev(j);
774 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
775 "cpufreq");
776 if (ret) {
777 cpufreq_cpu_put(managed_policy);
778 return ret;
779 }
780 }
781 return ret;
782}
783
784static int cpufreq_add_dev_interface(unsigned int cpu,
785 struct cpufreq_policy *policy,
786 struct sys_device *sys_dev)
787{
788 struct cpufreq_policy new_policy;
789 struct freq_attr **drv_attr;
790 unsigned long flags;
791 int ret = 0;
792 unsigned int j;
793
794 /* prepare interface data */
795 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
796 &sys_dev->kobj, "cpufreq");
797 if (ret)
798 return ret;
799
800 /* set up files for this cpu device */
801 drv_attr = cpufreq_driver->attr;
802 while ((drv_attr) && (*drv_attr)) {
803 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
804 if (ret)
805 goto err_out_kobj_put;
806 drv_attr++;
807 }
808 if (cpufreq_driver->get) {
809 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
810 if (ret)
811 goto err_out_kobj_put;
812 }
813 if (cpufreq_driver->target) {
814 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
815 if (ret)
816 goto err_out_kobj_put;
817 }
818 if (cpufreq_driver->bios_limit) {
819 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
820 if (ret)
821 goto err_out_kobj_put;
822 }
823
824 spin_lock_irqsave(&cpufreq_driver_lock, flags);
825 for_each_cpu(j, policy->cpus) {
826 if (!cpu_online(j))
827 continue;
828 per_cpu(cpufreq_cpu_data, j) = policy;
829 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
830 }
831 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
832
833 ret = cpufreq_add_dev_symlink(cpu, policy);
834 if (ret)
835 goto err_out_kobj_put;
836
837 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
838 /* assure that the starting sequence is run in __cpufreq_set_policy */
839 policy->governor = NULL;
840
841 /* set default policy */
842 ret = __cpufreq_set_policy(policy, &new_policy);
843 policy->user_policy.policy = policy->policy;
844 policy->user_policy.governor = policy->governor;
845
846 if (ret) {
847 pr_debug("setting policy failed\n");
848 if (cpufreq_driver->exit)
849 cpufreq_driver->exit(policy);
850 }
851 return ret;
852
853err_out_kobj_put:
854 kobject_put(&policy->kobj);
855 wait_for_completion(&policy->kobj_unregister);
856 return ret;
857}
858
859
860/**
861 * cpufreq_add_dev - add a CPU device
862 *
863 * Adds the cpufreq interface for a CPU device.
864 *
865 * The Oracle says: try running cpufreq registration/unregistration concurrently
866 * with with cpu hotplugging and all hell will break loose. Tried to clean this
867 * mess up, but more thorough testing is needed. - Mathieu
868 */
869static int cpufreq_add_dev(struct sys_device *sys_dev)
870{
871 unsigned int cpu = sys_dev->id;
872 int ret = 0, found = 0;
873 struct cpufreq_policy *policy;
874 unsigned long flags;
875 unsigned int j;
876#ifdef CONFIG_HOTPLUG_CPU
877 int sibling;
878#endif
879
880 if (cpu_is_offline(cpu))
881 return 0;
882
883 pr_debug("adding CPU %u\n", cpu);
884
885#ifdef CONFIG_SMP
886 /* check whether a different CPU already registered this
887 * CPU because it is in the same boat. */
888 policy = cpufreq_cpu_get(cpu);
889 if (unlikely(policy)) {
890 cpufreq_cpu_put(policy);
891 return 0;
892 }
893#endif
894
895 if (!try_module_get(cpufreq_driver->owner)) {
896 ret = -EINVAL;
897 goto module_out;
898 }
899
900 ret = -ENOMEM;
901 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
902 if (!policy)
903 goto nomem_out;
904
905 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
906 goto err_free_policy;
907
908 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
909 goto err_free_cpumask;
910
911 policy->cpu = cpu;
912 cpumask_copy(policy->cpus, cpumask_of(cpu));
913
914 /* Initially set CPU itself as the policy_cpu */
915 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
916 ret = (lock_policy_rwsem_write(cpu) < 0);
917 WARN_ON(ret);
918
919 init_completion(&policy->kobj_unregister);
920 INIT_WORK(&policy->update, handle_update);
921
922 /* Set governor before ->init, so that driver could check it */
923#ifdef CONFIG_HOTPLUG_CPU
924 for_each_online_cpu(sibling) {
925 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
926 if (cp && cp->governor &&
927 (cpumask_test_cpu(cpu, cp->related_cpus))) {
928 policy->governor = cp->governor;
929 found = 1;
930 break;
931 }
932 }
933#endif
934 if (!found)
935 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
936 /* call driver. From then on the cpufreq must be able
937 * to accept all calls to ->verify and ->setpolicy for this CPU
938 */
939 ret = cpufreq_driver->init(policy);
940 if (ret) {
941 pr_debug("initialization failed\n");
942 goto err_unlock_policy;
943 }
944 policy->user_policy.min = policy->min;
945 policy->user_policy.max = policy->max;
946
947 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
948 CPUFREQ_START, policy);
949
950 ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
951 if (ret) {
952 if (ret > 0)
953 /* This is a managed cpu, symlink created,
954 exit with 0 */
955 ret = 0;
956 goto err_unlock_policy;
957 }
958
959 ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
960 if (ret)
961 goto err_out_unregister;
962
963 unlock_policy_rwsem_write(cpu);
964
965 kobject_uevent(&policy->kobj, KOBJ_ADD);
966 module_put(cpufreq_driver->owner);
967 pr_debug("initialization complete\n");
968
969 return 0;
970
971
972err_out_unregister:
973 spin_lock_irqsave(&cpufreq_driver_lock, flags);
974 for_each_cpu(j, policy->cpus)
975 per_cpu(cpufreq_cpu_data, j) = NULL;
976 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
977
978 kobject_put(&policy->kobj);
979 wait_for_completion(&policy->kobj_unregister);
980
981err_unlock_policy:
982 unlock_policy_rwsem_write(cpu);
983 free_cpumask_var(policy->related_cpus);
984err_free_cpumask:
985 free_cpumask_var(policy->cpus);
986err_free_policy:
987 kfree(policy);
988nomem_out:
989 module_put(cpufreq_driver->owner);
990module_out:
991 return ret;
992}
993
994
995/**
996 * __cpufreq_remove_dev - remove a CPU device
997 *
998 * Removes the cpufreq interface for a CPU device.
999 * Caller should already have policy_rwsem in write mode for this CPU.
1000 * This routine frees the rwsem before returning.
1001 */
1002static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1003{
1004 unsigned int cpu = sys_dev->id;
1005 unsigned long flags;
1006 struct cpufreq_policy *data;
1007 struct kobject *kobj;
1008 struct completion *cmp;
1009#ifdef CONFIG_SMP
1010 struct sys_device *cpu_sys_dev;
1011 unsigned int j;
1012#endif
1013
1014 pr_debug("unregistering CPU %u\n", cpu);
1015
1016 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1017 data = per_cpu(cpufreq_cpu_data, cpu);
1018
1019 if (!data) {
1020 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1021 unlock_policy_rwsem_write(cpu);
1022 return -EINVAL;
1023 }
1024 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1025
1026
1027#ifdef CONFIG_SMP
1028 /* if this isn't the CPU which is the parent of the kobj, we
1029 * only need to unlink, put and exit
1030 */
1031 if (unlikely(cpu != data->cpu)) {
1032 pr_debug("removing link\n");
1033 cpumask_clear_cpu(cpu, data->cpus);
1034 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1035 kobj = &sys_dev->kobj;
1036 cpufreq_cpu_put(data);
1037 unlock_policy_rwsem_write(cpu);
1038 sysfs_remove_link(kobj, "cpufreq");
1039 return 0;
1040 }
1041#endif
1042
1043#ifdef CONFIG_SMP
1044
1045#ifdef CONFIG_HOTPLUG_CPU
1046 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1047 CPUFREQ_NAME_LEN);
1048#endif
1049
1050 /* if we have other CPUs still registered, we need to unlink them,
1051 * or else wait_for_completion below will lock up. Clean the
1052 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1053 * the sysfs links afterwards.
1054 */
1055 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1056 for_each_cpu(j, data->cpus) {
1057 if (j == cpu)
1058 continue;
1059 per_cpu(cpufreq_cpu_data, j) = NULL;
1060 }
1061 }
1062
1063 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1064
1065 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1066 for_each_cpu(j, data->cpus) {
1067 if (j == cpu)
1068 continue;
1069 pr_debug("removing link for cpu %u\n", j);
1070#ifdef CONFIG_HOTPLUG_CPU
1071 strncpy(per_cpu(cpufreq_cpu_governor, j),
1072 data->governor->name, CPUFREQ_NAME_LEN);
1073#endif
1074 cpu_sys_dev = get_cpu_sysdev(j);
1075 kobj = &cpu_sys_dev->kobj;
1076 unlock_policy_rwsem_write(cpu);
1077 sysfs_remove_link(kobj, "cpufreq");
1078 lock_policy_rwsem_write(cpu);
1079 cpufreq_cpu_put(data);
1080 }
1081 }
1082#else
1083 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1084#endif
1085
1086 if (cpufreq_driver->target)
1087 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1088
1089 kobj = &data->kobj;
1090 cmp = &data->kobj_unregister;
1091 unlock_policy_rwsem_write(cpu);
1092 kobject_put(kobj);
1093
1094 /* we need to make sure that the underlying kobj is actually
1095 * not referenced anymore by anybody before we proceed with
1096 * unloading.
1097 */
1098 pr_debug("waiting for dropping of refcount\n");
1099 wait_for_completion(cmp);
1100 pr_debug("wait complete\n");
1101
1102 lock_policy_rwsem_write(cpu);
1103 if (cpufreq_driver->exit)
1104 cpufreq_driver->exit(data);
1105 unlock_policy_rwsem_write(cpu);
1106
1107#ifdef CONFIG_HOTPLUG_CPU
1108 /* when the CPU which is the parent of the kobj is hotplugged
1109 * offline, check for siblings, and create cpufreq sysfs interface
1110 * and symlinks
1111 */
1112 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1113 /* first sibling now owns the new sysfs dir */
1114 cpumask_clear_cpu(cpu, data->cpus);
1115 cpufreq_add_dev(get_cpu_sysdev(cpumask_first(data->cpus)));
1116
1117 /* finally remove our own symlink */
1118 lock_policy_rwsem_write(cpu);
1119 __cpufreq_remove_dev(sys_dev);
1120 }
1121#endif
1122
1123 free_cpumask_var(data->related_cpus);
1124 free_cpumask_var(data->cpus);
1125 kfree(data);
1126
1127 return 0;
1128}
1129
1130
1131static int cpufreq_remove_dev(struct sys_device *sys_dev)
1132{
1133 unsigned int cpu = sys_dev->id;
1134 int retval;
1135
1136 if (cpu_is_offline(cpu))
1137 return 0;
1138
1139 if (unlikely(lock_policy_rwsem_write(cpu)))
1140 BUG();
1141
1142 retval = __cpufreq_remove_dev(sys_dev);
1143 return retval;
1144}
1145
1146
1147static void handle_update(struct work_struct *work)
1148{
1149 struct cpufreq_policy *policy =
1150 container_of(work, struct cpufreq_policy, update);
1151 unsigned int cpu = policy->cpu;
1152 pr_debug("handle_update for cpu %u called\n", cpu);
1153 cpufreq_update_policy(cpu);
1154}
1155
1156/**
1157 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1158 * @cpu: cpu number
1159 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1160 * @new_freq: CPU frequency the CPU actually runs at
1161 *
1162 * We adjust to current frequency first, and need to clean up later.
1163 * So either call to cpufreq_update_policy() or schedule handle_update()).
1164 */
1165static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1166 unsigned int new_freq)
1167{
1168 struct cpufreq_freqs freqs;
1169
1170 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1171 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1172
1173 freqs.cpu = cpu;
1174 freqs.old = old_freq;
1175 freqs.new = new_freq;
1176 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1177 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1178}
1179
1180
1181/**
1182 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1183 * @cpu: CPU number
1184 *
1185 * This is the last known freq, without actually getting it from the driver.
1186 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1187 */
1188unsigned int cpufreq_quick_get(unsigned int cpu)
1189{
1190 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1191 unsigned int ret_freq = 0;
1192
1193 if (policy) {
1194 ret_freq = policy->cur;
1195 cpufreq_cpu_put(policy);
1196 }
1197
1198 return ret_freq;
1199}
1200EXPORT_SYMBOL(cpufreq_quick_get);
1201
1202/**
1203 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1204 * @cpu: CPU number
1205 *
1206 * Just return the max possible frequency for a given CPU.
1207 */
1208unsigned int cpufreq_quick_get_max(unsigned int cpu)
1209{
1210 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1211 unsigned int ret_freq = 0;
1212
1213 if (policy) {
1214 ret_freq = policy->max;
1215 cpufreq_cpu_put(policy);
1216 }
1217
1218 return ret_freq;
1219}
1220EXPORT_SYMBOL(cpufreq_quick_get_max);
1221
1222
1223static unsigned int __cpufreq_get(unsigned int cpu)
1224{
1225 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1226 unsigned int ret_freq = 0;
1227
1228 if (!cpufreq_driver->get)
1229 return ret_freq;
1230
1231 ret_freq = cpufreq_driver->get(cpu);
1232
1233 if (ret_freq && policy->cur &&
1234 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1235 /* verify no discrepancy between actual and
1236 saved value exists */
1237 if (unlikely(ret_freq != policy->cur)) {
1238 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1239 schedule_work(&policy->update);
1240 }
1241 }
1242
1243 return ret_freq;
1244}
1245
1246/**
1247 * cpufreq_get - get the current CPU frequency (in kHz)
1248 * @cpu: CPU number
1249 *
1250 * Get the CPU current (static) CPU frequency
1251 */
1252unsigned int cpufreq_get(unsigned int cpu)
1253{
1254 unsigned int ret_freq = 0;
1255 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1256
1257 if (!policy)
1258 goto out;
1259
1260 if (unlikely(lock_policy_rwsem_read(cpu)))
1261 goto out_policy;
1262
1263 ret_freq = __cpufreq_get(cpu);
1264
1265 unlock_policy_rwsem_read(cpu);
1266
1267out_policy:
1268 cpufreq_cpu_put(policy);
1269out:
1270 return ret_freq;
1271}
1272EXPORT_SYMBOL(cpufreq_get);
1273
1274static struct sysdev_driver cpufreq_sysdev_driver = {
1275 .add = cpufreq_add_dev,
1276 .remove = cpufreq_remove_dev,
1277};
1278
1279
1280/**
1281 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1282 *
1283 * This function is only executed for the boot processor. The other CPUs
1284 * have been put offline by means of CPU hotplug.
1285 */
1286static int cpufreq_bp_suspend(void)
1287{
1288 int ret = 0;
1289
1290 int cpu = smp_processor_id();
1291 struct cpufreq_policy *cpu_policy;
1292
1293 pr_debug("suspending cpu %u\n", cpu);
1294
1295 /* If there's no policy for the boot CPU, we have nothing to do. */
1296 cpu_policy = cpufreq_cpu_get(cpu);
1297 if (!cpu_policy)
1298 return 0;
1299
1300 if (cpufreq_driver->suspend) {
1301 ret = cpufreq_driver->suspend(cpu_policy);
1302 if (ret)
1303 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1304 "step on CPU %u\n", cpu_policy->cpu);
1305 }
1306
1307 cpufreq_cpu_put(cpu_policy);
1308 return ret;
1309}
1310
1311/**
1312 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1313 *
1314 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1315 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1316 * restored. It will verify that the current freq is in sync with
1317 * what we believe it to be. This is a bit later than when it
1318 * should be, but nonethteless it's better than calling
1319 * cpufreq_driver->get() here which might re-enable interrupts...
1320 *
1321 * This function is only executed for the boot CPU. The other CPUs have not
1322 * been turned on yet.
1323 */
1324static void cpufreq_bp_resume(void)
1325{
1326 int ret = 0;
1327
1328 int cpu = smp_processor_id();
1329 struct cpufreq_policy *cpu_policy;
1330
1331 pr_debug("resuming cpu %u\n", cpu);
1332
1333 /* If there's no policy for the boot CPU, we have nothing to do. */
1334 cpu_policy = cpufreq_cpu_get(cpu);
1335 if (!cpu_policy)
1336 return;
1337
1338 if (cpufreq_driver->resume) {
1339 ret = cpufreq_driver->resume(cpu_policy);
1340 if (ret) {
1341 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1342 "step on CPU %u\n", cpu_policy->cpu);
1343 goto fail;
1344 }
1345 }
1346
1347 schedule_work(&cpu_policy->update);
1348
1349fail:
1350 cpufreq_cpu_put(cpu_policy);
1351}
1352
1353static struct syscore_ops cpufreq_syscore_ops = {
1354 .suspend = cpufreq_bp_suspend,
1355 .resume = cpufreq_bp_resume,
1356};
1357
1358
1359/*********************************************************************
1360 * NOTIFIER LISTS INTERFACE *
1361 *********************************************************************/
1362
1363/**
1364 * cpufreq_register_notifier - register a driver with cpufreq
1365 * @nb: notifier function to register
1366 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1367 *
1368 * Add a driver to one of two lists: either a list of drivers that
1369 * are notified about clock rate changes (once before and once after
1370 * the transition), or a list of drivers that are notified about
1371 * changes in cpufreq policy.
1372 *
1373 * This function may sleep, and has the same return conditions as
1374 * blocking_notifier_chain_register.
1375 */
1376int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1377{
1378 int ret;
1379
1380 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1381
1382 switch (list) {
1383 case CPUFREQ_TRANSITION_NOTIFIER:
1384 ret = srcu_notifier_chain_register(
1385 &cpufreq_transition_notifier_list, nb);
1386 break;
1387 case CPUFREQ_POLICY_NOTIFIER:
1388 ret = blocking_notifier_chain_register(
1389 &cpufreq_policy_notifier_list, nb);
1390 break;
1391 default:
1392 ret = -EINVAL;
1393 }
1394
1395 return ret;
1396}
1397EXPORT_SYMBOL(cpufreq_register_notifier);
1398
1399
1400/**
1401 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1402 * @nb: notifier block to be unregistered
1403 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1404 *
1405 * Remove a driver from the CPU frequency notifier list.
1406 *
1407 * This function may sleep, and has the same return conditions as
1408 * blocking_notifier_chain_unregister.
1409 */
1410int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1411{
1412 int ret;
1413
1414 switch (list) {
1415 case CPUFREQ_TRANSITION_NOTIFIER:
1416 ret = srcu_notifier_chain_unregister(
1417 &cpufreq_transition_notifier_list, nb);
1418 break;
1419 case CPUFREQ_POLICY_NOTIFIER:
1420 ret = blocking_notifier_chain_unregister(
1421 &cpufreq_policy_notifier_list, nb);
1422 break;
1423 default:
1424 ret = -EINVAL;
1425 }
1426
1427 return ret;
1428}
1429EXPORT_SYMBOL(cpufreq_unregister_notifier);
1430
1431
1432/*********************************************************************
1433 * GOVERNORS *
1434 *********************************************************************/
1435
1436
1437int __cpufreq_driver_target(struct cpufreq_policy *policy,
1438 unsigned int target_freq,
1439 unsigned int relation)
1440{
1441 int retval = -EINVAL;
1442
1443 pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1444 target_freq, relation);
1445 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1446 retval = cpufreq_driver->target(policy, target_freq, relation);
1447
1448 return retval;
1449}
1450EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1451
1452int cpufreq_driver_target(struct cpufreq_policy *policy,
1453 unsigned int target_freq,
1454 unsigned int relation)
1455{
1456 int ret = -EINVAL;
1457
1458 policy = cpufreq_cpu_get(policy->cpu);
1459 if (!policy)
1460 goto no_policy;
1461
1462 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1463 goto fail;
1464
1465 ret = __cpufreq_driver_target(policy, target_freq, relation);
1466
1467 unlock_policy_rwsem_write(policy->cpu);
1468
1469fail:
1470 cpufreq_cpu_put(policy);
1471no_policy:
1472 return ret;
1473}
1474EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1475
1476int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1477{
1478 int ret = 0;
1479
1480 policy = cpufreq_cpu_get(policy->cpu);
1481 if (!policy)
1482 return -EINVAL;
1483
1484 if (cpu_online(cpu) && cpufreq_driver->getavg)
1485 ret = cpufreq_driver->getavg(policy, cpu);
1486
1487 cpufreq_cpu_put(policy);
1488 return ret;
1489}
1490EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1491
1492/*
1493 * when "event" is CPUFREQ_GOV_LIMITS
1494 */
1495
1496static int __cpufreq_governor(struct cpufreq_policy *policy,
1497 unsigned int event)
1498{
1499 int ret;
1500
1501 /* Only must be defined when default governor is known to have latency
1502 restrictions, like e.g. conservative or ondemand.
1503 That this is the case is already ensured in Kconfig
1504 */
1505#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1506 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1507#else
1508 struct cpufreq_governor *gov = NULL;
1509#endif
1510
1511 if (policy->governor->max_transition_latency &&
1512 policy->cpuinfo.transition_latency >
1513 policy->governor->max_transition_latency) {
1514 if (!gov)
1515 return -EINVAL;
1516 else {
1517 printk(KERN_WARNING "%s governor failed, too long"
1518 " transition latency of HW, fallback"
1519 " to %s governor\n",
1520 policy->governor->name,
1521 gov->name);
1522 policy->governor = gov;
1523 }
1524 }
1525
1526 if (!try_module_get(policy->governor->owner))
1527 return -EINVAL;
1528
1529 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1530 policy->cpu, event);
1531 ret = policy->governor->governor(policy, event);
1532
1533 /* we keep one module reference alive for
1534 each CPU governed by this CPU */
1535 if ((event != CPUFREQ_GOV_START) || ret)
1536 module_put(policy->governor->owner);
1537 if ((event == CPUFREQ_GOV_STOP) && !ret)
1538 module_put(policy->governor->owner);
1539
1540 return ret;
1541}
1542
1543
1544int cpufreq_register_governor(struct cpufreq_governor *governor)
1545{
1546 int err;
1547
1548 if (!governor)
1549 return -EINVAL;
1550
1551 mutex_lock(&cpufreq_governor_mutex);
1552
1553 err = -EBUSY;
1554 if (__find_governor(governor->name) == NULL) {
1555 err = 0;
1556 list_add(&governor->governor_list, &cpufreq_governor_list);
1557 }
1558
1559 mutex_unlock(&cpufreq_governor_mutex);
1560 return err;
1561}
1562EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1563
1564
1565void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1566{
1567#ifdef CONFIG_HOTPLUG_CPU
1568 int cpu;
1569#endif
1570
1571 if (!governor)
1572 return;
1573
1574#ifdef CONFIG_HOTPLUG_CPU
1575 for_each_present_cpu(cpu) {
1576 if (cpu_online(cpu))
1577 continue;
1578 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1579 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1580 }
1581#endif
1582
1583 mutex_lock(&cpufreq_governor_mutex);
1584 list_del(&governor->governor_list);
1585 mutex_unlock(&cpufreq_governor_mutex);
1586 return;
1587}
1588EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1589
1590
1591
1592/*********************************************************************
1593 * POLICY INTERFACE *
1594 *********************************************************************/
1595
1596/**
1597 * cpufreq_get_policy - get the current cpufreq_policy
1598 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1599 * is written
1600 *
1601 * Reads the current cpufreq policy.
1602 */
1603int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1604{
1605 struct cpufreq_policy *cpu_policy;
1606 if (!policy)
1607 return -EINVAL;
1608
1609 cpu_policy = cpufreq_cpu_get(cpu);
1610 if (!cpu_policy)
1611 return -EINVAL;
1612
1613 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1614
1615 cpufreq_cpu_put(cpu_policy);
1616 return 0;
1617}
1618EXPORT_SYMBOL(cpufreq_get_policy);
1619
1620
1621/*
1622 * data : current policy.
1623 * policy : policy to be set.
1624 */
1625static int __cpufreq_set_policy(struct cpufreq_policy *data,
1626 struct cpufreq_policy *policy)
1627{
1628 int ret = 0;
1629
1630 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1631 policy->min, policy->max);
1632
1633 memcpy(&policy->cpuinfo, &data->cpuinfo,
1634 sizeof(struct cpufreq_cpuinfo));
1635
1636 if (policy->min > data->max || policy->max < data->min) {
1637 ret = -EINVAL;
1638 goto error_out;
1639 }
1640
1641 /* verify the cpu speed can be set within this limit */
1642 ret = cpufreq_driver->verify(policy);
1643 if (ret)
1644 goto error_out;
1645
1646 /* adjust if necessary - all reasons */
1647 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1648 CPUFREQ_ADJUST, policy);
1649
1650 /* adjust if necessary - hardware incompatibility*/
1651 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1652 CPUFREQ_INCOMPATIBLE, policy);
1653
1654 /* verify the cpu speed can be set within this limit,
1655 which might be different to the first one */
1656 ret = cpufreq_driver->verify(policy);
1657 if (ret)
1658 goto error_out;
1659
1660 /* notification of the new policy */
1661 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1662 CPUFREQ_NOTIFY, policy);
1663
1664 data->min = policy->min;
1665 data->max = policy->max;
1666
1667 pr_debug("new min and max freqs are %u - %u kHz\n",
1668 data->min, data->max);
1669
1670 if (cpufreq_driver->setpolicy) {
1671 data->policy = policy->policy;
1672 pr_debug("setting range\n");
1673 ret = cpufreq_driver->setpolicy(policy);
1674 } else {
1675 if (policy->governor != data->governor) {
1676 /* save old, working values */
1677 struct cpufreq_governor *old_gov = data->governor;
1678
1679 pr_debug("governor switch\n");
1680
1681 /* end old governor */
1682 if (data->governor)
1683 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1684
1685 /* start new governor */
1686 data->governor = policy->governor;
1687 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1688 /* new governor failed, so re-start old one */
1689 pr_debug("starting governor %s failed\n",
1690 data->governor->name);
1691 if (old_gov) {
1692 data->governor = old_gov;
1693 __cpufreq_governor(data,
1694 CPUFREQ_GOV_START);
1695 }
1696 ret = -EINVAL;
1697 goto error_out;
1698 }
1699 /* might be a policy change, too, so fall through */
1700 }
1701 pr_debug("governor: change or update limits\n");
1702 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1703 }
1704
1705error_out:
1706 return ret;
1707}
1708
1709/**
1710 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1711 * @cpu: CPU which shall be re-evaluated
1712 *
1713 * Useful for policy notifiers which have different necessities
1714 * at different times.
1715 */
1716int cpufreq_update_policy(unsigned int cpu)
1717{
1718 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1719 struct cpufreq_policy policy;
1720 int ret;
1721
1722 if (!data) {
1723 ret = -ENODEV;
1724 goto no_policy;
1725 }
1726
1727 if (unlikely(lock_policy_rwsem_write(cpu))) {
1728 ret = -EINVAL;
1729 goto fail;
1730 }
1731
1732 pr_debug("updating policy for CPU %u\n", cpu);
1733 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1734 policy.min = data->user_policy.min;
1735 policy.max = data->user_policy.max;
1736 policy.policy = data->user_policy.policy;
1737 policy.governor = data->user_policy.governor;
1738
1739 /* BIOS might change freq behind our back
1740 -> ask driver for current freq and notify governors about a change */
1741 if (cpufreq_driver->get) {
1742 policy.cur = cpufreq_driver->get(cpu);
1743 if (!data->cur) {
1744 pr_debug("Driver did not initialize current freq");
1745 data->cur = policy.cur;
1746 } else {
1747 if (data->cur != policy.cur)
1748 cpufreq_out_of_sync(cpu, data->cur,
1749 policy.cur);
1750 }
1751 }
1752
1753 ret = __cpufreq_set_policy(data, &policy);
1754
1755 unlock_policy_rwsem_write(cpu);
1756
1757fail:
1758 cpufreq_cpu_put(data);
1759no_policy:
1760 return ret;
1761}
1762EXPORT_SYMBOL(cpufreq_update_policy);
1763
1764static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1765 unsigned long action, void *hcpu)
1766{
1767 unsigned int cpu = (unsigned long)hcpu;
1768 struct sys_device *sys_dev;
1769
1770 sys_dev = get_cpu_sysdev(cpu);
1771 if (sys_dev) {
1772 switch (action) {
1773 case CPU_ONLINE:
1774 case CPU_ONLINE_FROZEN:
1775 cpufreq_add_dev(sys_dev);
1776 break;
1777 case CPU_DOWN_PREPARE:
1778 case CPU_DOWN_PREPARE_FROZEN:
1779 if (unlikely(lock_policy_rwsem_write(cpu)))
1780 BUG();
1781
1782 __cpufreq_remove_dev(sys_dev);
1783 break;
1784 case CPU_DOWN_FAILED:
1785 case CPU_DOWN_FAILED_FROZEN:
1786 cpufreq_add_dev(sys_dev);
1787 break;
1788 }
1789 }
1790 return NOTIFY_OK;
1791}
1792
1793static struct notifier_block __refdata cpufreq_cpu_notifier = {
1794 .notifier_call = cpufreq_cpu_callback,
1795};
1796
1797/*********************************************************************
1798 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1799 *********************************************************************/
1800
1801/**
1802 * cpufreq_register_driver - register a CPU Frequency driver
1803 * @driver_data: A struct cpufreq_driver containing the values#
1804 * submitted by the CPU Frequency driver.
1805 *
1806 * Registers a CPU Frequency driver to this core code. This code
1807 * returns zero on success, -EBUSY when another driver got here first
1808 * (and isn't unregistered in the meantime).
1809 *
1810 */
1811int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1812{
1813 unsigned long flags;
1814 int ret;
1815
1816 if (!driver_data || !driver_data->verify || !driver_data->init ||
1817 ((!driver_data->setpolicy) && (!driver_data->target)))
1818 return -EINVAL;
1819
1820 pr_debug("trying to register driver %s\n", driver_data->name);
1821
1822 if (driver_data->setpolicy)
1823 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1824
1825 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1826 if (cpufreq_driver) {
1827 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1828 return -EBUSY;
1829 }
1830 cpufreq_driver = driver_data;
1831 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1832
1833 ret = sysdev_driver_register(&cpu_sysdev_class,
1834 &cpufreq_sysdev_driver);
1835 if (ret)
1836 goto err_null_driver;
1837
1838 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1839 int i;
1840 ret = -ENODEV;
1841
1842 /* check for at least one working CPU */
1843 for (i = 0; i < nr_cpu_ids; i++)
1844 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1845 ret = 0;
1846 break;
1847 }
1848
1849 /* if all ->init() calls failed, unregister */
1850 if (ret) {
1851 pr_debug("no CPU initialized for driver %s\n",
1852 driver_data->name);
1853 goto err_sysdev_unreg;
1854 }
1855 }
1856
1857 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1858 pr_debug("driver %s up and running\n", driver_data->name);
1859
1860 return 0;
1861err_sysdev_unreg:
1862 sysdev_driver_unregister(&cpu_sysdev_class,
1863 &cpufreq_sysdev_driver);
1864err_null_driver:
1865 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1866 cpufreq_driver = NULL;
1867 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1868 return ret;
1869}
1870EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1871
1872
1873/**
1874 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1875 *
1876 * Unregister the current CPUFreq driver. Only call this if you have
1877 * the right to do so, i.e. if you have succeeded in initialising before!
1878 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1879 * currently not initialised.
1880 */
1881int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1882{
1883 unsigned long flags;
1884
1885 if (!cpufreq_driver || (driver != cpufreq_driver))
1886 return -EINVAL;
1887
1888 pr_debug("unregistering driver %s\n", driver->name);
1889
1890 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1891 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1892
1893 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1894 cpufreq_driver = NULL;
1895 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1896
1897 return 0;
1898}
1899EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1900
1901static int __init cpufreq_core_init(void)
1902{
1903 int cpu;
1904
1905 for_each_possible_cpu(cpu) {
1906 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1907 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1908 }
1909
1910 cpufreq_global_kobject = kobject_create_and_add("cpufreq",
1911 &cpu_sysdev_class.kset.kobj);
1912 BUG_ON(!cpufreq_global_kobject);
1913 register_syscore_ops(&cpufreq_syscore_ops);
1914
1915 return 0;
1916}
1917core_initcall(cpufreq_core_init);
1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
7 *
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/cpu.h>
21#include <linux/cpufreq.h>
22#include <linux/delay.h>
23#include <linux/device.h>
24#include <linux/init.h>
25#include <linux/kernel_stat.h>
26#include <linux/module.h>
27#include <linux/mutex.h>
28#include <linux/slab.h>
29#include <linux/suspend.h>
30#include <linux/tick.h>
31#include <trace/events/power.h>
32
33/**
34 * The "cpufreq driver" - the arch- or hardware-dependent low
35 * level driver of CPUFreq support, and its spinlock. This lock
36 * also protects the cpufreq_cpu_data array.
37 */
38static struct cpufreq_driver *cpufreq_driver;
39static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
40static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
41static DEFINE_RWLOCK(cpufreq_driver_lock);
42DEFINE_MUTEX(cpufreq_governor_lock);
43static LIST_HEAD(cpufreq_policy_list);
44
45/* This one keeps track of the previously set governor of a removed CPU */
46static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
47
48/* Flag to suspend/resume CPUFreq governors */
49static bool cpufreq_suspended;
50
51static inline bool has_target(void)
52{
53 return cpufreq_driver->target_index || cpufreq_driver->target;
54}
55
56/*
57 * rwsem to guarantee that cpufreq driver module doesn't unload during critical
58 * sections
59 */
60static DECLARE_RWSEM(cpufreq_rwsem);
61
62/* internal prototypes */
63static int __cpufreq_governor(struct cpufreq_policy *policy,
64 unsigned int event);
65static unsigned int __cpufreq_get(unsigned int cpu);
66static void handle_update(struct work_struct *work);
67
68/**
69 * Two notifier lists: the "policy" list is involved in the
70 * validation process for a new CPU frequency policy; the
71 * "transition" list for kernel code that needs to handle
72 * changes to devices when the CPU clock speed changes.
73 * The mutex locks both lists.
74 */
75static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
76static struct srcu_notifier_head cpufreq_transition_notifier_list;
77
78static bool init_cpufreq_transition_notifier_list_called;
79static int __init init_cpufreq_transition_notifier_list(void)
80{
81 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
82 init_cpufreq_transition_notifier_list_called = true;
83 return 0;
84}
85pure_initcall(init_cpufreq_transition_notifier_list);
86
87static int off __read_mostly;
88static int cpufreq_disabled(void)
89{
90 return off;
91}
92void disable_cpufreq(void)
93{
94 off = 1;
95}
96static LIST_HEAD(cpufreq_governor_list);
97static DEFINE_MUTEX(cpufreq_governor_mutex);
98
99bool have_governor_per_policy(void)
100{
101 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
102}
103EXPORT_SYMBOL_GPL(have_governor_per_policy);
104
105struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
106{
107 if (have_governor_per_policy())
108 return &policy->kobj;
109 else
110 return cpufreq_global_kobject;
111}
112EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
113
114static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
115{
116 u64 idle_time;
117 u64 cur_wall_time;
118 u64 busy_time;
119
120 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
121
122 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
123 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
124 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
125 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
126 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
127 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
128
129 idle_time = cur_wall_time - busy_time;
130 if (wall)
131 *wall = cputime_to_usecs(cur_wall_time);
132
133 return cputime_to_usecs(idle_time);
134}
135
136u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
137{
138 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
139
140 if (idle_time == -1ULL)
141 return get_cpu_idle_time_jiffy(cpu, wall);
142 else if (!io_busy)
143 idle_time += get_cpu_iowait_time_us(cpu, wall);
144
145 return idle_time;
146}
147EXPORT_SYMBOL_GPL(get_cpu_idle_time);
148
149/*
150 * This is a generic cpufreq init() routine which can be used by cpufreq
151 * drivers of SMP systems. It will do following:
152 * - validate & show freq table passed
153 * - set policies transition latency
154 * - policy->cpus with all possible CPUs
155 */
156int cpufreq_generic_init(struct cpufreq_policy *policy,
157 struct cpufreq_frequency_table *table,
158 unsigned int transition_latency)
159{
160 int ret;
161
162 ret = cpufreq_table_validate_and_show(policy, table);
163 if (ret) {
164 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
165 return ret;
166 }
167
168 policy->cpuinfo.transition_latency = transition_latency;
169
170 /*
171 * The driver only supports the SMP configuartion where all processors
172 * share the clock and voltage and clock.
173 */
174 cpumask_setall(policy->cpus);
175
176 return 0;
177}
178EXPORT_SYMBOL_GPL(cpufreq_generic_init);
179
180unsigned int cpufreq_generic_get(unsigned int cpu)
181{
182 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
183
184 if (!policy || IS_ERR(policy->clk)) {
185 pr_err("%s: No %s associated to cpu: %d\n",
186 __func__, policy ? "clk" : "policy", cpu);
187 return 0;
188 }
189
190 return clk_get_rate(policy->clk) / 1000;
191}
192EXPORT_SYMBOL_GPL(cpufreq_generic_get);
193
194/* Only for cpufreq core internal use */
195struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
196{
197 return per_cpu(cpufreq_cpu_data, cpu);
198}
199
200struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
201{
202 struct cpufreq_policy *policy = NULL;
203 unsigned long flags;
204
205 if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
206 return NULL;
207
208 if (!down_read_trylock(&cpufreq_rwsem))
209 return NULL;
210
211 /* get the cpufreq driver */
212 read_lock_irqsave(&cpufreq_driver_lock, flags);
213
214 if (cpufreq_driver) {
215 /* get the CPU */
216 policy = per_cpu(cpufreq_cpu_data, cpu);
217 if (policy)
218 kobject_get(&policy->kobj);
219 }
220
221 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
222
223 if (!policy)
224 up_read(&cpufreq_rwsem);
225
226 return policy;
227}
228EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
229
230void cpufreq_cpu_put(struct cpufreq_policy *policy)
231{
232 if (cpufreq_disabled())
233 return;
234
235 kobject_put(&policy->kobj);
236 up_read(&cpufreq_rwsem);
237}
238EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
239
240/*********************************************************************
241 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
242 *********************************************************************/
243
244/**
245 * adjust_jiffies - adjust the system "loops_per_jiffy"
246 *
247 * This function alters the system "loops_per_jiffy" for the clock
248 * speed change. Note that loops_per_jiffy cannot be updated on SMP
249 * systems as each CPU might be scaled differently. So, use the arch
250 * per-CPU loops_per_jiffy value wherever possible.
251 */
252#ifndef CONFIG_SMP
253static unsigned long l_p_j_ref;
254static unsigned int l_p_j_ref_freq;
255
256static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
257{
258 if (ci->flags & CPUFREQ_CONST_LOOPS)
259 return;
260
261 if (!l_p_j_ref_freq) {
262 l_p_j_ref = loops_per_jiffy;
263 l_p_j_ref_freq = ci->old;
264 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
265 l_p_j_ref, l_p_j_ref_freq);
266 }
267 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
268 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
269 ci->new);
270 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
271 loops_per_jiffy, ci->new);
272 }
273}
274#else
275static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
276{
277 return;
278}
279#endif
280
281static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
282 struct cpufreq_freqs *freqs, unsigned int state)
283{
284 BUG_ON(irqs_disabled());
285
286 if (cpufreq_disabled())
287 return;
288
289 freqs->flags = cpufreq_driver->flags;
290 pr_debug("notification %u of frequency transition to %u kHz\n",
291 state, freqs->new);
292
293 switch (state) {
294
295 case CPUFREQ_PRECHANGE:
296 /* detect if the driver reported a value as "old frequency"
297 * which is not equal to what the cpufreq core thinks is
298 * "old frequency".
299 */
300 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
301 if ((policy) && (policy->cpu == freqs->cpu) &&
302 (policy->cur) && (policy->cur != freqs->old)) {
303 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
304 freqs->old, policy->cur);
305 freqs->old = policy->cur;
306 }
307 }
308 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
309 CPUFREQ_PRECHANGE, freqs);
310 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
311 break;
312
313 case CPUFREQ_POSTCHANGE:
314 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
315 pr_debug("FREQ: %lu - CPU: %lu\n",
316 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
317 trace_cpu_frequency(freqs->new, freqs->cpu);
318 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
319 CPUFREQ_POSTCHANGE, freqs);
320 if (likely(policy) && likely(policy->cpu == freqs->cpu))
321 policy->cur = freqs->new;
322 break;
323 }
324}
325
326/**
327 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
328 * on frequency transition.
329 *
330 * This function calls the transition notifiers and the "adjust_jiffies"
331 * function. It is called twice on all CPU frequency changes that have
332 * external effects.
333 */
334static void cpufreq_notify_transition(struct cpufreq_policy *policy,
335 struct cpufreq_freqs *freqs, unsigned int state)
336{
337 for_each_cpu(freqs->cpu, policy->cpus)
338 __cpufreq_notify_transition(policy, freqs, state);
339}
340
341/* Do post notifications when there are chances that transition has failed */
342static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
343 struct cpufreq_freqs *freqs, int transition_failed)
344{
345 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
346 if (!transition_failed)
347 return;
348
349 swap(freqs->old, freqs->new);
350 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
351 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
352}
353
354void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
355 struct cpufreq_freqs *freqs)
356{
357wait:
358 wait_event(policy->transition_wait, !policy->transition_ongoing);
359
360 spin_lock(&policy->transition_lock);
361
362 if (unlikely(policy->transition_ongoing)) {
363 spin_unlock(&policy->transition_lock);
364 goto wait;
365 }
366
367 policy->transition_ongoing = true;
368
369 spin_unlock(&policy->transition_lock);
370
371 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
372}
373EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
374
375void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
376 struct cpufreq_freqs *freqs, int transition_failed)
377{
378 if (unlikely(WARN_ON(!policy->transition_ongoing)))
379 return;
380
381 cpufreq_notify_post_transition(policy, freqs, transition_failed);
382
383 policy->transition_ongoing = false;
384
385 wake_up(&policy->transition_wait);
386}
387EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
388
389
390/*********************************************************************
391 * SYSFS INTERFACE *
392 *********************************************************************/
393static ssize_t show_boost(struct kobject *kobj,
394 struct attribute *attr, char *buf)
395{
396 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
397}
398
399static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
400 const char *buf, size_t count)
401{
402 int ret, enable;
403
404 ret = sscanf(buf, "%d", &enable);
405 if (ret != 1 || enable < 0 || enable > 1)
406 return -EINVAL;
407
408 if (cpufreq_boost_trigger_state(enable)) {
409 pr_err("%s: Cannot %s BOOST!\n",
410 __func__, enable ? "enable" : "disable");
411 return -EINVAL;
412 }
413
414 pr_debug("%s: cpufreq BOOST %s\n",
415 __func__, enable ? "enabled" : "disabled");
416
417 return count;
418}
419define_one_global_rw(boost);
420
421static struct cpufreq_governor *__find_governor(const char *str_governor)
422{
423 struct cpufreq_governor *t;
424
425 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
426 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
427 return t;
428
429 return NULL;
430}
431
432/**
433 * cpufreq_parse_governor - parse a governor string
434 */
435static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
436 struct cpufreq_governor **governor)
437{
438 int err = -EINVAL;
439
440 if (!cpufreq_driver)
441 goto out;
442
443 if (cpufreq_driver->setpolicy) {
444 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
445 *policy = CPUFREQ_POLICY_PERFORMANCE;
446 err = 0;
447 } else if (!strnicmp(str_governor, "powersave",
448 CPUFREQ_NAME_LEN)) {
449 *policy = CPUFREQ_POLICY_POWERSAVE;
450 err = 0;
451 }
452 } else if (has_target()) {
453 struct cpufreq_governor *t;
454
455 mutex_lock(&cpufreq_governor_mutex);
456
457 t = __find_governor(str_governor);
458
459 if (t == NULL) {
460 int ret;
461
462 mutex_unlock(&cpufreq_governor_mutex);
463 ret = request_module("cpufreq_%s", str_governor);
464 mutex_lock(&cpufreq_governor_mutex);
465
466 if (ret == 0)
467 t = __find_governor(str_governor);
468 }
469
470 if (t != NULL) {
471 *governor = t;
472 err = 0;
473 }
474
475 mutex_unlock(&cpufreq_governor_mutex);
476 }
477out:
478 return err;
479}
480
481/**
482 * cpufreq_per_cpu_attr_read() / show_##file_name() -
483 * print out cpufreq information
484 *
485 * Write out information from cpufreq_driver->policy[cpu]; object must be
486 * "unsigned int".
487 */
488
489#define show_one(file_name, object) \
490static ssize_t show_##file_name \
491(struct cpufreq_policy *policy, char *buf) \
492{ \
493 return sprintf(buf, "%u\n", policy->object); \
494}
495
496show_one(cpuinfo_min_freq, cpuinfo.min_freq);
497show_one(cpuinfo_max_freq, cpuinfo.max_freq);
498show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
499show_one(scaling_min_freq, min);
500show_one(scaling_max_freq, max);
501show_one(scaling_cur_freq, cur);
502
503static int cpufreq_set_policy(struct cpufreq_policy *policy,
504 struct cpufreq_policy *new_policy);
505
506/**
507 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
508 */
509#define store_one(file_name, object) \
510static ssize_t store_##file_name \
511(struct cpufreq_policy *policy, const char *buf, size_t count) \
512{ \
513 int ret; \
514 struct cpufreq_policy new_policy; \
515 \
516 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
517 if (ret) \
518 return -EINVAL; \
519 \
520 ret = sscanf(buf, "%u", &new_policy.object); \
521 if (ret != 1) \
522 return -EINVAL; \
523 \
524 ret = cpufreq_set_policy(policy, &new_policy); \
525 policy->user_policy.object = policy->object; \
526 \
527 return ret ? ret : count; \
528}
529
530store_one(scaling_min_freq, min);
531store_one(scaling_max_freq, max);
532
533/**
534 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
535 */
536static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
537 char *buf)
538{
539 unsigned int cur_freq = __cpufreq_get(policy->cpu);
540 if (!cur_freq)
541 return sprintf(buf, "<unknown>");
542 return sprintf(buf, "%u\n", cur_freq);
543}
544
545/**
546 * show_scaling_governor - show the current policy for the specified CPU
547 */
548static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
549{
550 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
551 return sprintf(buf, "powersave\n");
552 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
553 return sprintf(buf, "performance\n");
554 else if (policy->governor)
555 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
556 policy->governor->name);
557 return -EINVAL;
558}
559
560/**
561 * store_scaling_governor - store policy for the specified CPU
562 */
563static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
564 const char *buf, size_t count)
565{
566 int ret;
567 char str_governor[16];
568 struct cpufreq_policy new_policy;
569
570 ret = cpufreq_get_policy(&new_policy, policy->cpu);
571 if (ret)
572 return ret;
573
574 ret = sscanf(buf, "%15s", str_governor);
575 if (ret != 1)
576 return -EINVAL;
577
578 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
579 &new_policy.governor))
580 return -EINVAL;
581
582 ret = cpufreq_set_policy(policy, &new_policy);
583
584 policy->user_policy.policy = policy->policy;
585 policy->user_policy.governor = policy->governor;
586
587 if (ret)
588 return ret;
589 else
590 return count;
591}
592
593/**
594 * show_scaling_driver - show the cpufreq driver currently loaded
595 */
596static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
597{
598 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
599}
600
601/**
602 * show_scaling_available_governors - show the available CPUfreq governors
603 */
604static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
605 char *buf)
606{
607 ssize_t i = 0;
608 struct cpufreq_governor *t;
609
610 if (!has_target()) {
611 i += sprintf(buf, "performance powersave");
612 goto out;
613 }
614
615 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
616 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
617 - (CPUFREQ_NAME_LEN + 2)))
618 goto out;
619 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
620 }
621out:
622 i += sprintf(&buf[i], "\n");
623 return i;
624}
625
626ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
627{
628 ssize_t i = 0;
629 unsigned int cpu;
630
631 for_each_cpu(cpu, mask) {
632 if (i)
633 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
634 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
635 if (i >= (PAGE_SIZE - 5))
636 break;
637 }
638 i += sprintf(&buf[i], "\n");
639 return i;
640}
641EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
642
643/**
644 * show_related_cpus - show the CPUs affected by each transition even if
645 * hw coordination is in use
646 */
647static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
648{
649 return cpufreq_show_cpus(policy->related_cpus, buf);
650}
651
652/**
653 * show_affected_cpus - show the CPUs affected by each transition
654 */
655static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
656{
657 return cpufreq_show_cpus(policy->cpus, buf);
658}
659
660static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
661 const char *buf, size_t count)
662{
663 unsigned int freq = 0;
664 unsigned int ret;
665
666 if (!policy->governor || !policy->governor->store_setspeed)
667 return -EINVAL;
668
669 ret = sscanf(buf, "%u", &freq);
670 if (ret != 1)
671 return -EINVAL;
672
673 policy->governor->store_setspeed(policy, freq);
674
675 return count;
676}
677
678static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
679{
680 if (!policy->governor || !policy->governor->show_setspeed)
681 return sprintf(buf, "<unsupported>\n");
682
683 return policy->governor->show_setspeed(policy, buf);
684}
685
686/**
687 * show_bios_limit - show the current cpufreq HW/BIOS limitation
688 */
689static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
690{
691 unsigned int limit;
692 int ret;
693 if (cpufreq_driver->bios_limit) {
694 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
695 if (!ret)
696 return sprintf(buf, "%u\n", limit);
697 }
698 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
699}
700
701cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
702cpufreq_freq_attr_ro(cpuinfo_min_freq);
703cpufreq_freq_attr_ro(cpuinfo_max_freq);
704cpufreq_freq_attr_ro(cpuinfo_transition_latency);
705cpufreq_freq_attr_ro(scaling_available_governors);
706cpufreq_freq_attr_ro(scaling_driver);
707cpufreq_freq_attr_ro(scaling_cur_freq);
708cpufreq_freq_attr_ro(bios_limit);
709cpufreq_freq_attr_ro(related_cpus);
710cpufreq_freq_attr_ro(affected_cpus);
711cpufreq_freq_attr_rw(scaling_min_freq);
712cpufreq_freq_attr_rw(scaling_max_freq);
713cpufreq_freq_attr_rw(scaling_governor);
714cpufreq_freq_attr_rw(scaling_setspeed);
715
716static struct attribute *default_attrs[] = {
717 &cpuinfo_min_freq.attr,
718 &cpuinfo_max_freq.attr,
719 &cpuinfo_transition_latency.attr,
720 &scaling_min_freq.attr,
721 &scaling_max_freq.attr,
722 &affected_cpus.attr,
723 &related_cpus.attr,
724 &scaling_governor.attr,
725 &scaling_driver.attr,
726 &scaling_available_governors.attr,
727 &scaling_setspeed.attr,
728 NULL
729};
730
731#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
732#define to_attr(a) container_of(a, struct freq_attr, attr)
733
734static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
735{
736 struct cpufreq_policy *policy = to_policy(kobj);
737 struct freq_attr *fattr = to_attr(attr);
738 ssize_t ret;
739
740 if (!down_read_trylock(&cpufreq_rwsem))
741 return -EINVAL;
742
743 down_read(&policy->rwsem);
744
745 if (fattr->show)
746 ret = fattr->show(policy, buf);
747 else
748 ret = -EIO;
749
750 up_read(&policy->rwsem);
751 up_read(&cpufreq_rwsem);
752
753 return ret;
754}
755
756static ssize_t store(struct kobject *kobj, struct attribute *attr,
757 const char *buf, size_t count)
758{
759 struct cpufreq_policy *policy = to_policy(kobj);
760 struct freq_attr *fattr = to_attr(attr);
761 ssize_t ret = -EINVAL;
762
763 get_online_cpus();
764
765 if (!cpu_online(policy->cpu))
766 goto unlock;
767
768 if (!down_read_trylock(&cpufreq_rwsem))
769 goto unlock;
770
771 down_write(&policy->rwsem);
772
773 if (fattr->store)
774 ret = fattr->store(policy, buf, count);
775 else
776 ret = -EIO;
777
778 up_write(&policy->rwsem);
779
780 up_read(&cpufreq_rwsem);
781unlock:
782 put_online_cpus();
783
784 return ret;
785}
786
787static void cpufreq_sysfs_release(struct kobject *kobj)
788{
789 struct cpufreq_policy *policy = to_policy(kobj);
790 pr_debug("last reference is dropped\n");
791 complete(&policy->kobj_unregister);
792}
793
794static const struct sysfs_ops sysfs_ops = {
795 .show = show,
796 .store = store,
797};
798
799static struct kobj_type ktype_cpufreq = {
800 .sysfs_ops = &sysfs_ops,
801 .default_attrs = default_attrs,
802 .release = cpufreq_sysfs_release,
803};
804
805struct kobject *cpufreq_global_kobject;
806EXPORT_SYMBOL(cpufreq_global_kobject);
807
808static int cpufreq_global_kobject_usage;
809
810int cpufreq_get_global_kobject(void)
811{
812 if (!cpufreq_global_kobject_usage++)
813 return kobject_add(cpufreq_global_kobject,
814 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
815
816 return 0;
817}
818EXPORT_SYMBOL(cpufreq_get_global_kobject);
819
820void cpufreq_put_global_kobject(void)
821{
822 if (!--cpufreq_global_kobject_usage)
823 kobject_del(cpufreq_global_kobject);
824}
825EXPORT_SYMBOL(cpufreq_put_global_kobject);
826
827int cpufreq_sysfs_create_file(const struct attribute *attr)
828{
829 int ret = cpufreq_get_global_kobject();
830
831 if (!ret) {
832 ret = sysfs_create_file(cpufreq_global_kobject, attr);
833 if (ret)
834 cpufreq_put_global_kobject();
835 }
836
837 return ret;
838}
839EXPORT_SYMBOL(cpufreq_sysfs_create_file);
840
841void cpufreq_sysfs_remove_file(const struct attribute *attr)
842{
843 sysfs_remove_file(cpufreq_global_kobject, attr);
844 cpufreq_put_global_kobject();
845}
846EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
847
848/* symlink affected CPUs */
849static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
850{
851 unsigned int j;
852 int ret = 0;
853
854 for_each_cpu(j, policy->cpus) {
855 struct device *cpu_dev;
856
857 if (j == policy->cpu)
858 continue;
859
860 pr_debug("Adding link for CPU: %u\n", j);
861 cpu_dev = get_cpu_device(j);
862 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
863 "cpufreq");
864 if (ret)
865 break;
866 }
867 return ret;
868}
869
870static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
871 struct device *dev)
872{
873 struct freq_attr **drv_attr;
874 int ret = 0;
875
876 /* prepare interface data */
877 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
878 &dev->kobj, "cpufreq");
879 if (ret)
880 return ret;
881
882 /* set up files for this cpu device */
883 drv_attr = cpufreq_driver->attr;
884 while ((drv_attr) && (*drv_attr)) {
885 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
886 if (ret)
887 goto err_out_kobj_put;
888 drv_attr++;
889 }
890 if (cpufreq_driver->get) {
891 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
892 if (ret)
893 goto err_out_kobj_put;
894 }
895 if (has_target()) {
896 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
897 if (ret)
898 goto err_out_kobj_put;
899 }
900 if (cpufreq_driver->bios_limit) {
901 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
902 if (ret)
903 goto err_out_kobj_put;
904 }
905
906 ret = cpufreq_add_dev_symlink(policy);
907 if (ret)
908 goto err_out_kobj_put;
909
910 return ret;
911
912err_out_kobj_put:
913 kobject_put(&policy->kobj);
914 wait_for_completion(&policy->kobj_unregister);
915 return ret;
916}
917
918static void cpufreq_init_policy(struct cpufreq_policy *policy)
919{
920 struct cpufreq_governor *gov = NULL;
921 struct cpufreq_policy new_policy;
922 int ret = 0;
923
924 memcpy(&new_policy, policy, sizeof(*policy));
925
926 /* Update governor of new_policy to the governor used before hotplug */
927 gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
928 if (gov)
929 pr_debug("Restoring governor %s for cpu %d\n",
930 policy->governor->name, policy->cpu);
931 else
932 gov = CPUFREQ_DEFAULT_GOVERNOR;
933
934 new_policy.governor = gov;
935
936 /* Use the default policy if its valid. */
937 if (cpufreq_driver->setpolicy)
938 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
939
940 /* set default policy */
941 ret = cpufreq_set_policy(policy, &new_policy);
942 if (ret) {
943 pr_debug("setting policy failed\n");
944 if (cpufreq_driver->exit)
945 cpufreq_driver->exit(policy);
946 }
947}
948
949#ifdef CONFIG_HOTPLUG_CPU
950static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
951 unsigned int cpu, struct device *dev)
952{
953 int ret = 0;
954 unsigned long flags;
955
956 if (has_target()) {
957 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
958 if (ret) {
959 pr_err("%s: Failed to stop governor\n", __func__);
960 return ret;
961 }
962 }
963
964 down_write(&policy->rwsem);
965
966 write_lock_irqsave(&cpufreq_driver_lock, flags);
967
968 cpumask_set_cpu(cpu, policy->cpus);
969 per_cpu(cpufreq_cpu_data, cpu) = policy;
970 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
971
972 up_write(&policy->rwsem);
973
974 if (has_target()) {
975 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
976 if (!ret)
977 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
978
979 if (ret) {
980 pr_err("%s: Failed to start governor\n", __func__);
981 return ret;
982 }
983 }
984
985 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
986}
987#endif
988
989static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
990{
991 struct cpufreq_policy *policy;
992 unsigned long flags;
993
994 read_lock_irqsave(&cpufreq_driver_lock, flags);
995
996 policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
997
998 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
999
1000 policy->governor = NULL;
1001
1002 return policy;
1003}
1004
1005static struct cpufreq_policy *cpufreq_policy_alloc(void)
1006{
1007 struct cpufreq_policy *policy;
1008
1009 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1010 if (!policy)
1011 return NULL;
1012
1013 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1014 goto err_free_policy;
1015
1016 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1017 goto err_free_cpumask;
1018
1019 INIT_LIST_HEAD(&policy->policy_list);
1020 init_rwsem(&policy->rwsem);
1021 spin_lock_init(&policy->transition_lock);
1022 init_waitqueue_head(&policy->transition_wait);
1023
1024 return policy;
1025
1026err_free_cpumask:
1027 free_cpumask_var(policy->cpus);
1028err_free_policy:
1029 kfree(policy);
1030
1031 return NULL;
1032}
1033
1034static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1035{
1036 struct kobject *kobj;
1037 struct completion *cmp;
1038
1039 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1040 CPUFREQ_REMOVE_POLICY, policy);
1041
1042 down_read(&policy->rwsem);
1043 kobj = &policy->kobj;
1044 cmp = &policy->kobj_unregister;
1045 up_read(&policy->rwsem);
1046 kobject_put(kobj);
1047
1048 /*
1049 * We need to make sure that the underlying kobj is
1050 * actually not referenced anymore by anybody before we
1051 * proceed with unloading.
1052 */
1053 pr_debug("waiting for dropping of refcount\n");
1054 wait_for_completion(cmp);
1055 pr_debug("wait complete\n");
1056}
1057
1058static void cpufreq_policy_free(struct cpufreq_policy *policy)
1059{
1060 free_cpumask_var(policy->related_cpus);
1061 free_cpumask_var(policy->cpus);
1062 kfree(policy);
1063}
1064
1065static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1066{
1067 if (WARN_ON(cpu == policy->cpu))
1068 return;
1069
1070 down_write(&policy->rwsem);
1071
1072 policy->last_cpu = policy->cpu;
1073 policy->cpu = cpu;
1074
1075 up_write(&policy->rwsem);
1076
1077 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1078 CPUFREQ_UPDATE_POLICY_CPU, policy);
1079}
1080
1081static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1082{
1083 unsigned int j, cpu = dev->id;
1084 int ret = -ENOMEM;
1085 struct cpufreq_policy *policy;
1086 unsigned long flags;
1087 bool recover_policy = cpufreq_suspended;
1088#ifdef CONFIG_HOTPLUG_CPU
1089 struct cpufreq_policy *tpolicy;
1090#endif
1091
1092 if (cpu_is_offline(cpu))
1093 return 0;
1094
1095 pr_debug("adding CPU %u\n", cpu);
1096
1097#ifdef CONFIG_SMP
1098 /* check whether a different CPU already registered this
1099 * CPU because it is in the same boat. */
1100 policy = cpufreq_cpu_get(cpu);
1101 if (unlikely(policy)) {
1102 cpufreq_cpu_put(policy);
1103 return 0;
1104 }
1105#endif
1106
1107 if (!down_read_trylock(&cpufreq_rwsem))
1108 return 0;
1109
1110#ifdef CONFIG_HOTPLUG_CPU
1111 /* Check if this cpu was hot-unplugged earlier and has siblings */
1112 read_lock_irqsave(&cpufreq_driver_lock, flags);
1113 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1114 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1115 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1116 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1117 up_read(&cpufreq_rwsem);
1118 return ret;
1119 }
1120 }
1121 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1122#endif
1123
1124 /*
1125 * Restore the saved policy when doing light-weight init and fall back
1126 * to the full init if that fails.
1127 */
1128 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1129 if (!policy) {
1130 recover_policy = false;
1131 policy = cpufreq_policy_alloc();
1132 if (!policy)
1133 goto nomem_out;
1134 }
1135
1136 /*
1137 * In the resume path, since we restore a saved policy, the assignment
1138 * to policy->cpu is like an update of the existing policy, rather than
1139 * the creation of a brand new one. So we need to perform this update
1140 * by invoking update_policy_cpu().
1141 */
1142 if (recover_policy && cpu != policy->cpu)
1143 update_policy_cpu(policy, cpu);
1144 else
1145 policy->cpu = cpu;
1146
1147 cpumask_copy(policy->cpus, cpumask_of(cpu));
1148
1149 init_completion(&policy->kobj_unregister);
1150 INIT_WORK(&policy->update, handle_update);
1151
1152 /* call driver. From then on the cpufreq must be able
1153 * to accept all calls to ->verify and ->setpolicy for this CPU
1154 */
1155 ret = cpufreq_driver->init(policy);
1156 if (ret) {
1157 pr_debug("initialization failed\n");
1158 goto err_set_policy_cpu;
1159 }
1160
1161 /* related cpus should atleast have policy->cpus */
1162 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1163
1164 /*
1165 * affected cpus must always be the one, which are online. We aren't
1166 * managing offline cpus here.
1167 */
1168 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1169
1170 if (!recover_policy) {
1171 policy->user_policy.min = policy->min;
1172 policy->user_policy.max = policy->max;
1173 }
1174
1175 down_write(&policy->rwsem);
1176 write_lock_irqsave(&cpufreq_driver_lock, flags);
1177 for_each_cpu(j, policy->cpus)
1178 per_cpu(cpufreq_cpu_data, j) = policy;
1179 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1180
1181 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1182 policy->cur = cpufreq_driver->get(policy->cpu);
1183 if (!policy->cur) {
1184 pr_err("%s: ->get() failed\n", __func__);
1185 goto err_get_freq;
1186 }
1187 }
1188
1189 /*
1190 * Sometimes boot loaders set CPU frequency to a value outside of
1191 * frequency table present with cpufreq core. In such cases CPU might be
1192 * unstable if it has to run on that frequency for long duration of time
1193 * and so its better to set it to a frequency which is specified in
1194 * freq-table. This also makes cpufreq stats inconsistent as
1195 * cpufreq-stats would fail to register because current frequency of CPU
1196 * isn't found in freq-table.
1197 *
1198 * Because we don't want this change to effect boot process badly, we go
1199 * for the next freq which is >= policy->cur ('cur' must be set by now,
1200 * otherwise we will end up setting freq to lowest of the table as 'cur'
1201 * is initialized to zero).
1202 *
1203 * We are passing target-freq as "policy->cur - 1" otherwise
1204 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1205 * equal to target-freq.
1206 */
1207 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1208 && has_target()) {
1209 /* Are we running at unknown frequency ? */
1210 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1211 if (ret == -EINVAL) {
1212 /* Warn user and fix it */
1213 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1214 __func__, policy->cpu, policy->cur);
1215 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1216 CPUFREQ_RELATION_L);
1217
1218 /*
1219 * Reaching here after boot in a few seconds may not
1220 * mean that system will remain stable at "unknown"
1221 * frequency for longer duration. Hence, a BUG_ON().
1222 */
1223 BUG_ON(ret);
1224 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1225 __func__, policy->cpu, policy->cur);
1226 }
1227 }
1228
1229 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1230 CPUFREQ_START, policy);
1231
1232 if (!recover_policy) {
1233 ret = cpufreq_add_dev_interface(policy, dev);
1234 if (ret)
1235 goto err_out_unregister;
1236 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1237 CPUFREQ_CREATE_POLICY, policy);
1238 }
1239
1240 write_lock_irqsave(&cpufreq_driver_lock, flags);
1241 list_add(&policy->policy_list, &cpufreq_policy_list);
1242 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1243
1244 cpufreq_init_policy(policy);
1245
1246 if (!recover_policy) {
1247 policy->user_policy.policy = policy->policy;
1248 policy->user_policy.governor = policy->governor;
1249 }
1250 up_write(&policy->rwsem);
1251
1252 kobject_uevent(&policy->kobj, KOBJ_ADD);
1253 up_read(&cpufreq_rwsem);
1254
1255 pr_debug("initialization complete\n");
1256
1257 return 0;
1258
1259err_out_unregister:
1260err_get_freq:
1261 write_lock_irqsave(&cpufreq_driver_lock, flags);
1262 for_each_cpu(j, policy->cpus)
1263 per_cpu(cpufreq_cpu_data, j) = NULL;
1264 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1265
1266 if (cpufreq_driver->exit)
1267 cpufreq_driver->exit(policy);
1268err_set_policy_cpu:
1269 if (recover_policy) {
1270 /* Do not leave stale fallback data behind. */
1271 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1272 cpufreq_policy_put_kobj(policy);
1273 }
1274 cpufreq_policy_free(policy);
1275
1276nomem_out:
1277 up_read(&cpufreq_rwsem);
1278
1279 return ret;
1280}
1281
1282/**
1283 * cpufreq_add_dev - add a CPU device
1284 *
1285 * Adds the cpufreq interface for a CPU device.
1286 *
1287 * The Oracle says: try running cpufreq registration/unregistration concurrently
1288 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1289 * mess up, but more thorough testing is needed. - Mathieu
1290 */
1291static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1292{
1293 return __cpufreq_add_dev(dev, sif);
1294}
1295
1296static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
1297 unsigned int old_cpu)
1298{
1299 struct device *cpu_dev;
1300 int ret;
1301
1302 /* first sibling now owns the new sysfs dir */
1303 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
1304
1305 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1306 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1307 if (ret) {
1308 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1309
1310 down_write(&policy->rwsem);
1311 cpumask_set_cpu(old_cpu, policy->cpus);
1312 up_write(&policy->rwsem);
1313
1314 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1315 "cpufreq");
1316
1317 return -EINVAL;
1318 }
1319
1320 return cpu_dev->id;
1321}
1322
1323static int __cpufreq_remove_dev_prepare(struct device *dev,
1324 struct subsys_interface *sif)
1325{
1326 unsigned int cpu = dev->id, cpus;
1327 int new_cpu, ret;
1328 unsigned long flags;
1329 struct cpufreq_policy *policy;
1330
1331 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1332
1333 write_lock_irqsave(&cpufreq_driver_lock, flags);
1334
1335 policy = per_cpu(cpufreq_cpu_data, cpu);
1336
1337 /* Save the policy somewhere when doing a light-weight tear-down */
1338 if (cpufreq_suspended)
1339 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1340
1341 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1342
1343 if (!policy) {
1344 pr_debug("%s: No cpu_data found\n", __func__);
1345 return -EINVAL;
1346 }
1347
1348 if (has_target()) {
1349 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1350 if (ret) {
1351 pr_err("%s: Failed to stop governor\n", __func__);
1352 return ret;
1353 }
1354 }
1355
1356 if (!cpufreq_driver->setpolicy)
1357 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1358 policy->governor->name, CPUFREQ_NAME_LEN);
1359
1360 down_read(&policy->rwsem);
1361 cpus = cpumask_weight(policy->cpus);
1362 up_read(&policy->rwsem);
1363
1364 if (cpu != policy->cpu) {
1365 sysfs_remove_link(&dev->kobj, "cpufreq");
1366 } else if (cpus > 1) {
1367 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
1368 if (new_cpu >= 0) {
1369 update_policy_cpu(policy, new_cpu);
1370
1371 if (!cpufreq_suspended)
1372 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1373 __func__, new_cpu, cpu);
1374 }
1375 } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
1376 cpufreq_driver->stop_cpu(policy);
1377 }
1378
1379 return 0;
1380}
1381
1382static int __cpufreq_remove_dev_finish(struct device *dev,
1383 struct subsys_interface *sif)
1384{
1385 unsigned int cpu = dev->id, cpus;
1386 int ret;
1387 unsigned long flags;
1388 struct cpufreq_policy *policy;
1389
1390 read_lock_irqsave(&cpufreq_driver_lock, flags);
1391 policy = per_cpu(cpufreq_cpu_data, cpu);
1392 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1393
1394 if (!policy) {
1395 pr_debug("%s: No cpu_data found\n", __func__);
1396 return -EINVAL;
1397 }
1398
1399 down_write(&policy->rwsem);
1400 cpus = cpumask_weight(policy->cpus);
1401
1402 if (cpus > 1)
1403 cpumask_clear_cpu(cpu, policy->cpus);
1404 up_write(&policy->rwsem);
1405
1406 /* If cpu is last user of policy, free policy */
1407 if (cpus == 1) {
1408 if (has_target()) {
1409 ret = __cpufreq_governor(policy,
1410 CPUFREQ_GOV_POLICY_EXIT);
1411 if (ret) {
1412 pr_err("%s: Failed to exit governor\n",
1413 __func__);
1414 return ret;
1415 }
1416 }
1417
1418 if (!cpufreq_suspended)
1419 cpufreq_policy_put_kobj(policy);
1420
1421 /*
1422 * Perform the ->exit() even during light-weight tear-down,
1423 * since this is a core component, and is essential for the
1424 * subsequent light-weight ->init() to succeed.
1425 */
1426 if (cpufreq_driver->exit)
1427 cpufreq_driver->exit(policy);
1428
1429 /* Remove policy from list of active policies */
1430 write_lock_irqsave(&cpufreq_driver_lock, flags);
1431 list_del(&policy->policy_list);
1432 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1433
1434 if (!cpufreq_suspended)
1435 cpufreq_policy_free(policy);
1436 } else if (has_target()) {
1437 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1438 if (!ret)
1439 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1440
1441 if (ret) {
1442 pr_err("%s: Failed to start governor\n", __func__);
1443 return ret;
1444 }
1445 }
1446
1447 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1448 return 0;
1449}
1450
1451/**
1452 * cpufreq_remove_dev - remove a CPU device
1453 *
1454 * Removes the cpufreq interface for a CPU device.
1455 */
1456static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1457{
1458 unsigned int cpu = dev->id;
1459 int ret;
1460
1461 if (cpu_is_offline(cpu))
1462 return 0;
1463
1464 ret = __cpufreq_remove_dev_prepare(dev, sif);
1465
1466 if (!ret)
1467 ret = __cpufreq_remove_dev_finish(dev, sif);
1468
1469 return ret;
1470}
1471
1472static void handle_update(struct work_struct *work)
1473{
1474 struct cpufreq_policy *policy =
1475 container_of(work, struct cpufreq_policy, update);
1476 unsigned int cpu = policy->cpu;
1477 pr_debug("handle_update for cpu %u called\n", cpu);
1478 cpufreq_update_policy(cpu);
1479}
1480
1481/**
1482 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1483 * in deep trouble.
1484 * @cpu: cpu number
1485 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1486 * @new_freq: CPU frequency the CPU actually runs at
1487 *
1488 * We adjust to current frequency first, and need to clean up later.
1489 * So either call to cpufreq_update_policy() or schedule handle_update()).
1490 */
1491static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1492 unsigned int new_freq)
1493{
1494 struct cpufreq_policy *policy;
1495 struct cpufreq_freqs freqs;
1496 unsigned long flags;
1497
1498 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1499 old_freq, new_freq);
1500
1501 freqs.old = old_freq;
1502 freqs.new = new_freq;
1503
1504 read_lock_irqsave(&cpufreq_driver_lock, flags);
1505 policy = per_cpu(cpufreq_cpu_data, cpu);
1506 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1507
1508 cpufreq_freq_transition_begin(policy, &freqs);
1509 cpufreq_freq_transition_end(policy, &freqs, 0);
1510}
1511
1512/**
1513 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1514 * @cpu: CPU number
1515 *
1516 * This is the last known freq, without actually getting it from the driver.
1517 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1518 */
1519unsigned int cpufreq_quick_get(unsigned int cpu)
1520{
1521 struct cpufreq_policy *policy;
1522 unsigned int ret_freq = 0;
1523
1524 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1525 return cpufreq_driver->get(cpu);
1526
1527 policy = cpufreq_cpu_get(cpu);
1528 if (policy) {
1529 ret_freq = policy->cur;
1530 cpufreq_cpu_put(policy);
1531 }
1532
1533 return ret_freq;
1534}
1535EXPORT_SYMBOL(cpufreq_quick_get);
1536
1537/**
1538 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1539 * @cpu: CPU number
1540 *
1541 * Just return the max possible frequency for a given CPU.
1542 */
1543unsigned int cpufreq_quick_get_max(unsigned int cpu)
1544{
1545 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1546 unsigned int ret_freq = 0;
1547
1548 if (policy) {
1549 ret_freq = policy->max;
1550 cpufreq_cpu_put(policy);
1551 }
1552
1553 return ret_freq;
1554}
1555EXPORT_SYMBOL(cpufreq_quick_get_max);
1556
1557static unsigned int __cpufreq_get(unsigned int cpu)
1558{
1559 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1560 unsigned int ret_freq = 0;
1561
1562 if (!cpufreq_driver->get)
1563 return ret_freq;
1564
1565 ret_freq = cpufreq_driver->get(cpu);
1566
1567 if (ret_freq && policy->cur &&
1568 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1569 /* verify no discrepancy between actual and
1570 saved value exists */
1571 if (unlikely(ret_freq != policy->cur)) {
1572 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1573 schedule_work(&policy->update);
1574 }
1575 }
1576
1577 return ret_freq;
1578}
1579
1580/**
1581 * cpufreq_get - get the current CPU frequency (in kHz)
1582 * @cpu: CPU number
1583 *
1584 * Get the CPU current (static) CPU frequency
1585 */
1586unsigned int cpufreq_get(unsigned int cpu)
1587{
1588 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1589 unsigned int ret_freq = 0;
1590
1591 if (policy) {
1592 down_read(&policy->rwsem);
1593 ret_freq = __cpufreq_get(cpu);
1594 up_read(&policy->rwsem);
1595
1596 cpufreq_cpu_put(policy);
1597 }
1598
1599 return ret_freq;
1600}
1601EXPORT_SYMBOL(cpufreq_get);
1602
1603static struct subsys_interface cpufreq_interface = {
1604 .name = "cpufreq",
1605 .subsys = &cpu_subsys,
1606 .add_dev = cpufreq_add_dev,
1607 .remove_dev = cpufreq_remove_dev,
1608};
1609
1610/*
1611 * In case platform wants some specific frequency to be configured
1612 * during suspend..
1613 */
1614int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1615{
1616 int ret;
1617
1618 if (!policy->suspend_freq) {
1619 pr_err("%s: suspend_freq can't be zero\n", __func__);
1620 return -EINVAL;
1621 }
1622
1623 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1624 policy->suspend_freq);
1625
1626 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1627 CPUFREQ_RELATION_H);
1628 if (ret)
1629 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1630 __func__, policy->suspend_freq, ret);
1631
1632 return ret;
1633}
1634EXPORT_SYMBOL(cpufreq_generic_suspend);
1635
1636/**
1637 * cpufreq_suspend() - Suspend CPUFreq governors
1638 *
1639 * Called during system wide Suspend/Hibernate cycles for suspending governors
1640 * as some platforms can't change frequency after this point in suspend cycle.
1641 * Because some of the devices (like: i2c, regulators, etc) they use for
1642 * changing frequency are suspended quickly after this point.
1643 */
1644void cpufreq_suspend(void)
1645{
1646 struct cpufreq_policy *policy;
1647
1648 if (!cpufreq_driver)
1649 return;
1650
1651 if (!has_target())
1652 return;
1653
1654 pr_debug("%s: Suspending Governors\n", __func__);
1655
1656 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1657 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1658 pr_err("%s: Failed to stop governor for policy: %p\n",
1659 __func__, policy);
1660 else if (cpufreq_driver->suspend
1661 && cpufreq_driver->suspend(policy))
1662 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1663 policy);
1664 }
1665
1666 cpufreq_suspended = true;
1667}
1668
1669/**
1670 * cpufreq_resume() - Resume CPUFreq governors
1671 *
1672 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1673 * are suspended with cpufreq_suspend().
1674 */
1675void cpufreq_resume(void)
1676{
1677 struct cpufreq_policy *policy;
1678
1679 if (!cpufreq_driver)
1680 return;
1681
1682 if (!has_target())
1683 return;
1684
1685 pr_debug("%s: Resuming Governors\n", __func__);
1686
1687 cpufreq_suspended = false;
1688
1689 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1690 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1691 pr_err("%s: Failed to resume driver: %p\n", __func__,
1692 policy);
1693 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1694 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1695 pr_err("%s: Failed to start governor for policy: %p\n",
1696 __func__, policy);
1697
1698 /*
1699 * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1700 * policy in list. It will verify that the current freq is in
1701 * sync with what we believe it to be.
1702 */
1703 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1704 schedule_work(&policy->update);
1705 }
1706}
1707
1708/**
1709 * cpufreq_get_current_driver - return current driver's name
1710 *
1711 * Return the name string of the currently loaded cpufreq driver
1712 * or NULL, if none.
1713 */
1714const char *cpufreq_get_current_driver(void)
1715{
1716 if (cpufreq_driver)
1717 return cpufreq_driver->name;
1718
1719 return NULL;
1720}
1721EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1722
1723/*********************************************************************
1724 * NOTIFIER LISTS INTERFACE *
1725 *********************************************************************/
1726
1727/**
1728 * cpufreq_register_notifier - register a driver with cpufreq
1729 * @nb: notifier function to register
1730 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1731 *
1732 * Add a driver to one of two lists: either a list of drivers that
1733 * are notified about clock rate changes (once before and once after
1734 * the transition), or a list of drivers that are notified about
1735 * changes in cpufreq policy.
1736 *
1737 * This function may sleep, and has the same return conditions as
1738 * blocking_notifier_chain_register.
1739 */
1740int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1741{
1742 int ret;
1743
1744 if (cpufreq_disabled())
1745 return -EINVAL;
1746
1747 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1748
1749 switch (list) {
1750 case CPUFREQ_TRANSITION_NOTIFIER:
1751 ret = srcu_notifier_chain_register(
1752 &cpufreq_transition_notifier_list, nb);
1753 break;
1754 case CPUFREQ_POLICY_NOTIFIER:
1755 ret = blocking_notifier_chain_register(
1756 &cpufreq_policy_notifier_list, nb);
1757 break;
1758 default:
1759 ret = -EINVAL;
1760 }
1761
1762 return ret;
1763}
1764EXPORT_SYMBOL(cpufreq_register_notifier);
1765
1766/**
1767 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1768 * @nb: notifier block to be unregistered
1769 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1770 *
1771 * Remove a driver from the CPU frequency notifier list.
1772 *
1773 * This function may sleep, and has the same return conditions as
1774 * blocking_notifier_chain_unregister.
1775 */
1776int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1777{
1778 int ret;
1779
1780 if (cpufreq_disabled())
1781 return -EINVAL;
1782
1783 switch (list) {
1784 case CPUFREQ_TRANSITION_NOTIFIER:
1785 ret = srcu_notifier_chain_unregister(
1786 &cpufreq_transition_notifier_list, nb);
1787 break;
1788 case CPUFREQ_POLICY_NOTIFIER:
1789 ret = blocking_notifier_chain_unregister(
1790 &cpufreq_policy_notifier_list, nb);
1791 break;
1792 default:
1793 ret = -EINVAL;
1794 }
1795
1796 return ret;
1797}
1798EXPORT_SYMBOL(cpufreq_unregister_notifier);
1799
1800
1801/*********************************************************************
1802 * GOVERNORS *
1803 *********************************************************************/
1804
1805int __cpufreq_driver_target(struct cpufreq_policy *policy,
1806 unsigned int target_freq,
1807 unsigned int relation)
1808{
1809 int retval = -EINVAL;
1810 unsigned int old_target_freq = target_freq;
1811
1812 if (cpufreq_disabled())
1813 return -ENODEV;
1814
1815 /* Make sure that target_freq is within supported range */
1816 if (target_freq > policy->max)
1817 target_freq = policy->max;
1818 if (target_freq < policy->min)
1819 target_freq = policy->min;
1820
1821 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1822 policy->cpu, target_freq, relation, old_target_freq);
1823
1824 /*
1825 * This might look like a redundant call as we are checking it again
1826 * after finding index. But it is left intentionally for cases where
1827 * exactly same freq is called again and so we can save on few function
1828 * calls.
1829 */
1830 if (target_freq == policy->cur)
1831 return 0;
1832
1833 if (cpufreq_driver->target)
1834 retval = cpufreq_driver->target(policy, target_freq, relation);
1835 else if (cpufreq_driver->target_index) {
1836 struct cpufreq_frequency_table *freq_table;
1837 struct cpufreq_freqs freqs;
1838 bool notify;
1839 int index;
1840
1841 freq_table = cpufreq_frequency_get_table(policy->cpu);
1842 if (unlikely(!freq_table)) {
1843 pr_err("%s: Unable to find freq_table\n", __func__);
1844 goto out;
1845 }
1846
1847 retval = cpufreq_frequency_table_target(policy, freq_table,
1848 target_freq, relation, &index);
1849 if (unlikely(retval)) {
1850 pr_err("%s: Unable to find matching freq\n", __func__);
1851 goto out;
1852 }
1853
1854 if (freq_table[index].frequency == policy->cur) {
1855 retval = 0;
1856 goto out;
1857 }
1858
1859 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1860
1861 if (notify) {
1862 freqs.old = policy->cur;
1863 freqs.new = freq_table[index].frequency;
1864 freqs.flags = 0;
1865
1866 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1867 __func__, policy->cpu, freqs.old, freqs.new);
1868
1869 cpufreq_freq_transition_begin(policy, &freqs);
1870 }
1871
1872 retval = cpufreq_driver->target_index(policy, index);
1873 if (retval)
1874 pr_err("%s: Failed to change cpu frequency: %d\n",
1875 __func__, retval);
1876
1877 if (notify)
1878 cpufreq_freq_transition_end(policy, &freqs, retval);
1879 }
1880
1881out:
1882 return retval;
1883}
1884EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1885
1886int cpufreq_driver_target(struct cpufreq_policy *policy,
1887 unsigned int target_freq,
1888 unsigned int relation)
1889{
1890 int ret = -EINVAL;
1891
1892 down_write(&policy->rwsem);
1893
1894 ret = __cpufreq_driver_target(policy, target_freq, relation);
1895
1896 up_write(&policy->rwsem);
1897
1898 return ret;
1899}
1900EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1901
1902/*
1903 * when "event" is CPUFREQ_GOV_LIMITS
1904 */
1905
1906static int __cpufreq_governor(struct cpufreq_policy *policy,
1907 unsigned int event)
1908{
1909 int ret;
1910
1911 /* Only must be defined when default governor is known to have latency
1912 restrictions, like e.g. conservative or ondemand.
1913 That this is the case is already ensured in Kconfig
1914 */
1915#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1916 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1917#else
1918 struct cpufreq_governor *gov = NULL;
1919#endif
1920
1921 /* Don't start any governor operations if we are entering suspend */
1922 if (cpufreq_suspended)
1923 return 0;
1924
1925 if (policy->governor->max_transition_latency &&
1926 policy->cpuinfo.transition_latency >
1927 policy->governor->max_transition_latency) {
1928 if (!gov)
1929 return -EINVAL;
1930 else {
1931 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1932 policy->governor->name, gov->name);
1933 policy->governor = gov;
1934 }
1935 }
1936
1937 if (event == CPUFREQ_GOV_POLICY_INIT)
1938 if (!try_module_get(policy->governor->owner))
1939 return -EINVAL;
1940
1941 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1942 policy->cpu, event);
1943
1944 mutex_lock(&cpufreq_governor_lock);
1945 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
1946 || (!policy->governor_enabled
1947 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
1948 mutex_unlock(&cpufreq_governor_lock);
1949 return -EBUSY;
1950 }
1951
1952 if (event == CPUFREQ_GOV_STOP)
1953 policy->governor_enabled = false;
1954 else if (event == CPUFREQ_GOV_START)
1955 policy->governor_enabled = true;
1956
1957 mutex_unlock(&cpufreq_governor_lock);
1958
1959 ret = policy->governor->governor(policy, event);
1960
1961 if (!ret) {
1962 if (event == CPUFREQ_GOV_POLICY_INIT)
1963 policy->governor->initialized++;
1964 else if (event == CPUFREQ_GOV_POLICY_EXIT)
1965 policy->governor->initialized--;
1966 } else {
1967 /* Restore original values */
1968 mutex_lock(&cpufreq_governor_lock);
1969 if (event == CPUFREQ_GOV_STOP)
1970 policy->governor_enabled = true;
1971 else if (event == CPUFREQ_GOV_START)
1972 policy->governor_enabled = false;
1973 mutex_unlock(&cpufreq_governor_lock);
1974 }
1975
1976 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
1977 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
1978 module_put(policy->governor->owner);
1979
1980 return ret;
1981}
1982
1983int cpufreq_register_governor(struct cpufreq_governor *governor)
1984{
1985 int err;
1986
1987 if (!governor)
1988 return -EINVAL;
1989
1990 if (cpufreq_disabled())
1991 return -ENODEV;
1992
1993 mutex_lock(&cpufreq_governor_mutex);
1994
1995 governor->initialized = 0;
1996 err = -EBUSY;
1997 if (__find_governor(governor->name) == NULL) {
1998 err = 0;
1999 list_add(&governor->governor_list, &cpufreq_governor_list);
2000 }
2001
2002 mutex_unlock(&cpufreq_governor_mutex);
2003 return err;
2004}
2005EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2006
2007void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2008{
2009 int cpu;
2010
2011 if (!governor)
2012 return;
2013
2014 if (cpufreq_disabled())
2015 return;
2016
2017 for_each_present_cpu(cpu) {
2018 if (cpu_online(cpu))
2019 continue;
2020 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2021 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2022 }
2023
2024 mutex_lock(&cpufreq_governor_mutex);
2025 list_del(&governor->governor_list);
2026 mutex_unlock(&cpufreq_governor_mutex);
2027 return;
2028}
2029EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2030
2031
2032/*********************************************************************
2033 * POLICY INTERFACE *
2034 *********************************************************************/
2035
2036/**
2037 * cpufreq_get_policy - get the current cpufreq_policy
2038 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2039 * is written
2040 *
2041 * Reads the current cpufreq policy.
2042 */
2043int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2044{
2045 struct cpufreq_policy *cpu_policy;
2046 if (!policy)
2047 return -EINVAL;
2048
2049 cpu_policy = cpufreq_cpu_get(cpu);
2050 if (!cpu_policy)
2051 return -EINVAL;
2052
2053 memcpy(policy, cpu_policy, sizeof(*policy));
2054
2055 cpufreq_cpu_put(cpu_policy);
2056 return 0;
2057}
2058EXPORT_SYMBOL(cpufreq_get_policy);
2059
2060/*
2061 * policy : current policy.
2062 * new_policy: policy to be set.
2063 */
2064static int cpufreq_set_policy(struct cpufreq_policy *policy,
2065 struct cpufreq_policy *new_policy)
2066{
2067 struct cpufreq_governor *old_gov;
2068 int ret;
2069
2070 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2071 new_policy->cpu, new_policy->min, new_policy->max);
2072
2073 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2074
2075 if (new_policy->min > policy->max || new_policy->max < policy->min)
2076 return -EINVAL;
2077
2078 /* verify the cpu speed can be set within this limit */
2079 ret = cpufreq_driver->verify(new_policy);
2080 if (ret)
2081 return ret;
2082
2083 /* adjust if necessary - all reasons */
2084 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2085 CPUFREQ_ADJUST, new_policy);
2086
2087 /* adjust if necessary - hardware incompatibility*/
2088 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2089 CPUFREQ_INCOMPATIBLE, new_policy);
2090
2091 /*
2092 * verify the cpu speed can be set within this limit, which might be
2093 * different to the first one
2094 */
2095 ret = cpufreq_driver->verify(new_policy);
2096 if (ret)
2097 return ret;
2098
2099 /* notification of the new policy */
2100 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2101 CPUFREQ_NOTIFY, new_policy);
2102
2103 policy->min = new_policy->min;
2104 policy->max = new_policy->max;
2105
2106 pr_debug("new min and max freqs are %u - %u kHz\n",
2107 policy->min, policy->max);
2108
2109 if (cpufreq_driver->setpolicy) {
2110 policy->policy = new_policy->policy;
2111 pr_debug("setting range\n");
2112 return cpufreq_driver->setpolicy(new_policy);
2113 }
2114
2115 if (new_policy->governor == policy->governor)
2116 goto out;
2117
2118 pr_debug("governor switch\n");
2119
2120 /* save old, working values */
2121 old_gov = policy->governor;
2122 /* end old governor */
2123 if (old_gov) {
2124 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2125 up_write(&policy->rwsem);
2126 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2127 down_write(&policy->rwsem);
2128 }
2129
2130 /* start new governor */
2131 policy->governor = new_policy->governor;
2132 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2133 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2134 goto out;
2135
2136 up_write(&policy->rwsem);
2137 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2138 down_write(&policy->rwsem);
2139 }
2140
2141 /* new governor failed, so re-start old one */
2142 pr_debug("starting governor %s failed\n", policy->governor->name);
2143 if (old_gov) {
2144 policy->governor = old_gov;
2145 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2146 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2147 }
2148
2149 return -EINVAL;
2150
2151 out:
2152 pr_debug("governor: change or update limits\n");
2153 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2154}
2155
2156/**
2157 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2158 * @cpu: CPU which shall be re-evaluated
2159 *
2160 * Useful for policy notifiers which have different necessities
2161 * at different times.
2162 */
2163int cpufreq_update_policy(unsigned int cpu)
2164{
2165 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2166 struct cpufreq_policy new_policy;
2167 int ret;
2168
2169 if (!policy) {
2170 ret = -ENODEV;
2171 goto no_policy;
2172 }
2173
2174 down_write(&policy->rwsem);
2175
2176 pr_debug("updating policy for CPU %u\n", cpu);
2177 memcpy(&new_policy, policy, sizeof(*policy));
2178 new_policy.min = policy->user_policy.min;
2179 new_policy.max = policy->user_policy.max;
2180 new_policy.policy = policy->user_policy.policy;
2181 new_policy.governor = policy->user_policy.governor;
2182
2183 /*
2184 * BIOS might change freq behind our back
2185 * -> ask driver for current freq and notify governors about a change
2186 */
2187 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2188 new_policy.cur = cpufreq_driver->get(cpu);
2189 if (WARN_ON(!new_policy.cur)) {
2190 ret = -EIO;
2191 goto no_policy;
2192 }
2193
2194 if (!policy->cur) {
2195 pr_debug("Driver did not initialize current freq\n");
2196 policy->cur = new_policy.cur;
2197 } else {
2198 if (policy->cur != new_policy.cur && has_target())
2199 cpufreq_out_of_sync(cpu, policy->cur,
2200 new_policy.cur);
2201 }
2202 }
2203
2204 ret = cpufreq_set_policy(policy, &new_policy);
2205
2206 up_write(&policy->rwsem);
2207
2208 cpufreq_cpu_put(policy);
2209no_policy:
2210 return ret;
2211}
2212EXPORT_SYMBOL(cpufreq_update_policy);
2213
2214static int cpufreq_cpu_callback(struct notifier_block *nfb,
2215 unsigned long action, void *hcpu)
2216{
2217 unsigned int cpu = (unsigned long)hcpu;
2218 struct device *dev;
2219
2220 dev = get_cpu_device(cpu);
2221 if (dev) {
2222 switch (action & ~CPU_TASKS_FROZEN) {
2223 case CPU_ONLINE:
2224 __cpufreq_add_dev(dev, NULL);
2225 break;
2226
2227 case CPU_DOWN_PREPARE:
2228 __cpufreq_remove_dev_prepare(dev, NULL);
2229 break;
2230
2231 case CPU_POST_DEAD:
2232 __cpufreq_remove_dev_finish(dev, NULL);
2233 break;
2234
2235 case CPU_DOWN_FAILED:
2236 __cpufreq_add_dev(dev, NULL);
2237 break;
2238 }
2239 }
2240 return NOTIFY_OK;
2241}
2242
2243static struct notifier_block __refdata cpufreq_cpu_notifier = {
2244 .notifier_call = cpufreq_cpu_callback,
2245};
2246
2247/*********************************************************************
2248 * BOOST *
2249 *********************************************************************/
2250static int cpufreq_boost_set_sw(int state)
2251{
2252 struct cpufreq_frequency_table *freq_table;
2253 struct cpufreq_policy *policy;
2254 int ret = -EINVAL;
2255
2256 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2257 freq_table = cpufreq_frequency_get_table(policy->cpu);
2258 if (freq_table) {
2259 ret = cpufreq_frequency_table_cpuinfo(policy,
2260 freq_table);
2261 if (ret) {
2262 pr_err("%s: Policy frequency update failed\n",
2263 __func__);
2264 break;
2265 }
2266 policy->user_policy.max = policy->max;
2267 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2268 }
2269 }
2270
2271 return ret;
2272}
2273
2274int cpufreq_boost_trigger_state(int state)
2275{
2276 unsigned long flags;
2277 int ret = 0;
2278
2279 if (cpufreq_driver->boost_enabled == state)
2280 return 0;
2281
2282 write_lock_irqsave(&cpufreq_driver_lock, flags);
2283 cpufreq_driver->boost_enabled = state;
2284 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2285
2286 ret = cpufreq_driver->set_boost(state);
2287 if (ret) {
2288 write_lock_irqsave(&cpufreq_driver_lock, flags);
2289 cpufreq_driver->boost_enabled = !state;
2290 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2291
2292 pr_err("%s: Cannot %s BOOST\n",
2293 __func__, state ? "enable" : "disable");
2294 }
2295
2296 return ret;
2297}
2298
2299int cpufreq_boost_supported(void)
2300{
2301 if (likely(cpufreq_driver))
2302 return cpufreq_driver->boost_supported;
2303
2304 return 0;
2305}
2306EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2307
2308int cpufreq_boost_enabled(void)
2309{
2310 return cpufreq_driver->boost_enabled;
2311}
2312EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2313
2314/*********************************************************************
2315 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2316 *********************************************************************/
2317
2318/**
2319 * cpufreq_register_driver - register a CPU Frequency driver
2320 * @driver_data: A struct cpufreq_driver containing the values#
2321 * submitted by the CPU Frequency driver.
2322 *
2323 * Registers a CPU Frequency driver to this core code. This code
2324 * returns zero on success, -EBUSY when another driver got here first
2325 * (and isn't unregistered in the meantime).
2326 *
2327 */
2328int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2329{
2330 unsigned long flags;
2331 int ret;
2332
2333 if (cpufreq_disabled())
2334 return -ENODEV;
2335
2336 if (!driver_data || !driver_data->verify || !driver_data->init ||
2337 !(driver_data->setpolicy || driver_data->target_index ||
2338 driver_data->target) ||
2339 (driver_data->setpolicy && (driver_data->target_index ||
2340 driver_data->target)))
2341 return -EINVAL;
2342
2343 pr_debug("trying to register driver %s\n", driver_data->name);
2344
2345 if (driver_data->setpolicy)
2346 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2347
2348 write_lock_irqsave(&cpufreq_driver_lock, flags);
2349 if (cpufreq_driver) {
2350 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2351 return -EEXIST;
2352 }
2353 cpufreq_driver = driver_data;
2354 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2355
2356 if (cpufreq_boost_supported()) {
2357 /*
2358 * Check if driver provides function to enable boost -
2359 * if not, use cpufreq_boost_set_sw as default
2360 */
2361 if (!cpufreq_driver->set_boost)
2362 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2363
2364 ret = cpufreq_sysfs_create_file(&boost.attr);
2365 if (ret) {
2366 pr_err("%s: cannot register global BOOST sysfs file\n",
2367 __func__);
2368 goto err_null_driver;
2369 }
2370 }
2371
2372 ret = subsys_interface_register(&cpufreq_interface);
2373 if (ret)
2374 goto err_boost_unreg;
2375
2376 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2377 int i;
2378 ret = -ENODEV;
2379
2380 /* check for at least one working CPU */
2381 for (i = 0; i < nr_cpu_ids; i++)
2382 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2383 ret = 0;
2384 break;
2385 }
2386
2387 /* if all ->init() calls failed, unregister */
2388 if (ret) {
2389 pr_debug("no CPU initialized for driver %s\n",
2390 driver_data->name);
2391 goto err_if_unreg;
2392 }
2393 }
2394
2395 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2396 pr_debug("driver %s up and running\n", driver_data->name);
2397
2398 return 0;
2399err_if_unreg:
2400 subsys_interface_unregister(&cpufreq_interface);
2401err_boost_unreg:
2402 if (cpufreq_boost_supported())
2403 cpufreq_sysfs_remove_file(&boost.attr);
2404err_null_driver:
2405 write_lock_irqsave(&cpufreq_driver_lock, flags);
2406 cpufreq_driver = NULL;
2407 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2408 return ret;
2409}
2410EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2411
2412/**
2413 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2414 *
2415 * Unregister the current CPUFreq driver. Only call this if you have
2416 * the right to do so, i.e. if you have succeeded in initialising before!
2417 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2418 * currently not initialised.
2419 */
2420int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2421{
2422 unsigned long flags;
2423
2424 if (!cpufreq_driver || (driver != cpufreq_driver))
2425 return -EINVAL;
2426
2427 pr_debug("unregistering driver %s\n", driver->name);
2428
2429 subsys_interface_unregister(&cpufreq_interface);
2430 if (cpufreq_boost_supported())
2431 cpufreq_sysfs_remove_file(&boost.attr);
2432
2433 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2434
2435 down_write(&cpufreq_rwsem);
2436 write_lock_irqsave(&cpufreq_driver_lock, flags);
2437
2438 cpufreq_driver = NULL;
2439
2440 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2441 up_write(&cpufreq_rwsem);
2442
2443 return 0;
2444}
2445EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2446
2447static int __init cpufreq_core_init(void)
2448{
2449 if (cpufreq_disabled())
2450 return -ENODEV;
2451
2452 cpufreq_global_kobject = kobject_create();
2453 BUG_ON(!cpufreq_global_kobject);
2454
2455 return 0;
2456}
2457core_initcall(cpufreq_core_init);