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