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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/cpufreq/cpufreq.c
4 *
5 * Copyright (C) 2001 Russell King
6 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
7 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
8 *
9 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
10 * Added handling for CPU hotplug
11 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
12 * Fix handling for CPU hotplug -- affected CPUs
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/cpu.h>
18#include <linux/cpufreq.h>
19#include <linux/cpu_cooling.h>
20#include <linux/delay.h>
21#include <linux/device.h>
22#include <linux/init.h>
23#include <linux/kernel_stat.h>
24#include <linux/module.h>
25#include <linux/mutex.h>
26#include <linux/pm_qos.h>
27#include <linux/slab.h>
28#include <linux/suspend.h>
29#include <linux/syscore_ops.h>
30#include <linux/tick.h>
31#include <linux/units.h>
32#include <trace/events/power.h>
33
34static LIST_HEAD(cpufreq_policy_list);
35
36/* Macros to iterate over CPU policies */
37#define for_each_suitable_policy(__policy, __active) \
38 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
39 if ((__active) == !policy_is_inactive(__policy))
40
41#define for_each_active_policy(__policy) \
42 for_each_suitable_policy(__policy, true)
43#define for_each_inactive_policy(__policy) \
44 for_each_suitable_policy(__policy, false)
45
46/* Iterate over governors */
47static LIST_HEAD(cpufreq_governor_list);
48#define for_each_governor(__governor) \
49 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
50
51static char default_governor[CPUFREQ_NAME_LEN];
52
53/*
54 * The "cpufreq driver" - the arch- or hardware-dependent low
55 * level driver of CPUFreq support, and its spinlock. This lock
56 * also protects the cpufreq_cpu_data array.
57 */
58static struct cpufreq_driver *cpufreq_driver;
59static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
60static DEFINE_RWLOCK(cpufreq_driver_lock);
61
62static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance);
63bool cpufreq_supports_freq_invariance(void)
64{
65 return static_branch_likely(&cpufreq_freq_invariance);
66}
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
76bool has_target_index(void)
77{
78 return !!cpufreq_driver->target_index;
79}
80
81/* internal prototypes */
82static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
83static int cpufreq_init_governor(struct cpufreq_policy *policy);
84static void cpufreq_exit_governor(struct cpufreq_policy *policy);
85static void cpufreq_governor_limits(struct cpufreq_policy *policy);
86static int cpufreq_set_policy(struct cpufreq_policy *policy,
87 struct cpufreq_governor *new_gov,
88 unsigned int new_pol);
89static bool cpufreq_boost_supported(void);
90
91/*
92 * Two notifier lists: the "policy" list is involved in the
93 * validation process for a new CPU frequency policy; the
94 * "transition" list for kernel code that needs to handle
95 * changes to devices when the CPU clock speed changes.
96 * The mutex locks both lists.
97 */
98static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
99SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
100
101static int off __read_mostly;
102static int cpufreq_disabled(void)
103{
104 return off;
105}
106void disable_cpufreq(void)
107{
108 off = 1;
109}
110static DEFINE_MUTEX(cpufreq_governor_mutex);
111
112bool have_governor_per_policy(void)
113{
114 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
115}
116EXPORT_SYMBOL_GPL(have_governor_per_policy);
117
118static struct kobject *cpufreq_global_kobject;
119
120struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
121{
122 if (have_governor_per_policy())
123 return &policy->kobj;
124 else
125 return cpufreq_global_kobject;
126}
127EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
128
129static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
130{
131 struct kernel_cpustat kcpustat;
132 u64 cur_wall_time;
133 u64 idle_time;
134 u64 busy_time;
135
136 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
137
138 kcpustat_cpu_fetch(&kcpustat, cpu);
139
140 busy_time = kcpustat.cpustat[CPUTIME_USER];
141 busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
142 busy_time += kcpustat.cpustat[CPUTIME_IRQ];
143 busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
144 busy_time += kcpustat.cpustat[CPUTIME_STEAL];
145 busy_time += kcpustat.cpustat[CPUTIME_NICE];
146
147 idle_time = cur_wall_time - busy_time;
148 if (wall)
149 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
150
151 return div_u64(idle_time, NSEC_PER_USEC);
152}
153
154u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
155{
156 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
157
158 if (idle_time == -1ULL)
159 return get_cpu_idle_time_jiffy(cpu, wall);
160 else if (!io_busy)
161 idle_time += get_cpu_iowait_time_us(cpu, wall);
162
163 return idle_time;
164}
165EXPORT_SYMBOL_GPL(get_cpu_idle_time);
166
167/*
168 * This is a generic cpufreq init() routine which can be used by cpufreq
169 * drivers of SMP systems. It will do following:
170 * - validate & show freq table passed
171 * - set policies transition latency
172 * - policy->cpus with all possible CPUs
173 */
174void cpufreq_generic_init(struct cpufreq_policy *policy,
175 struct cpufreq_frequency_table *table,
176 unsigned int transition_latency)
177{
178 policy->freq_table = table;
179 policy->cpuinfo.transition_latency = transition_latency;
180
181 /*
182 * The driver only supports the SMP configuration where all processors
183 * share the clock and voltage and clock.
184 */
185 cpumask_setall(policy->cpus);
186}
187EXPORT_SYMBOL_GPL(cpufreq_generic_init);
188
189struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
190{
191 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
192
193 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
194}
195EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
196
197unsigned int cpufreq_generic_get(unsigned int cpu)
198{
199 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
200
201 if (!policy || IS_ERR(policy->clk)) {
202 pr_err("%s: No %s associated to cpu: %d\n",
203 __func__, policy ? "clk" : "policy", cpu);
204 return 0;
205 }
206
207 return clk_get_rate(policy->clk) / 1000;
208}
209EXPORT_SYMBOL_GPL(cpufreq_generic_get);
210
211/**
212 * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
213 * @cpu: CPU to find the policy for.
214 *
215 * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
216 * the kobject reference counter of that policy. Return a valid policy on
217 * success or NULL on failure.
218 *
219 * The policy returned by this function has to be released with the help of
220 * cpufreq_cpu_put() to balance its kobject reference counter properly.
221 */
222struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
223{
224 struct cpufreq_policy *policy = NULL;
225 unsigned long flags;
226
227 if (WARN_ON(cpu >= nr_cpu_ids))
228 return NULL;
229
230 /* get the cpufreq driver */
231 read_lock_irqsave(&cpufreq_driver_lock, flags);
232
233 if (cpufreq_driver) {
234 /* get the CPU */
235 policy = cpufreq_cpu_get_raw(cpu);
236 if (policy)
237 kobject_get(&policy->kobj);
238 }
239
240 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
241
242 return policy;
243}
244EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
245
246/**
247 * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
248 * @policy: cpufreq policy returned by cpufreq_cpu_get().
249 */
250void cpufreq_cpu_put(struct cpufreq_policy *policy)
251{
252 kobject_put(&policy->kobj);
253}
254EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
255
256/**
257 * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
258 * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
259 */
260void cpufreq_cpu_release(struct cpufreq_policy *policy)
261{
262 if (WARN_ON(!policy))
263 return;
264
265 lockdep_assert_held(&policy->rwsem);
266
267 up_write(&policy->rwsem);
268
269 cpufreq_cpu_put(policy);
270}
271
272/**
273 * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
274 * @cpu: CPU to find the policy for.
275 *
276 * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
277 * if the policy returned by it is not NULL, acquire its rwsem for writing.
278 * Return the policy if it is active or release it and return NULL otherwise.
279 *
280 * The policy returned by this function has to be released with the help of
281 * cpufreq_cpu_release() in order to release its rwsem and balance its usage
282 * counter properly.
283 */
284struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
285{
286 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
287
288 if (!policy)
289 return NULL;
290
291 down_write(&policy->rwsem);
292
293 if (policy_is_inactive(policy)) {
294 cpufreq_cpu_release(policy);
295 return NULL;
296 }
297
298 return policy;
299}
300
301/*********************************************************************
302 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
303 *********************************************************************/
304
305/**
306 * adjust_jiffies - Adjust the system "loops_per_jiffy".
307 * @val: CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
308 * @ci: Frequency change information.
309 *
310 * This function alters the system "loops_per_jiffy" for the clock
311 * speed change. Note that loops_per_jiffy cannot be updated on SMP
312 * systems as each CPU might be scaled differently. So, use the arch
313 * per-CPU loops_per_jiffy value wherever possible.
314 */
315static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
316{
317#ifndef CONFIG_SMP
318 static unsigned long l_p_j_ref;
319 static unsigned int l_p_j_ref_freq;
320
321 if (ci->flags & CPUFREQ_CONST_LOOPS)
322 return;
323
324 if (!l_p_j_ref_freq) {
325 l_p_j_ref = loops_per_jiffy;
326 l_p_j_ref_freq = ci->old;
327 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
328 l_p_j_ref, l_p_j_ref_freq);
329 }
330 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
331 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
332 ci->new);
333 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
334 loops_per_jiffy, ci->new);
335 }
336#endif
337}
338
339/**
340 * cpufreq_notify_transition - Notify frequency transition and adjust jiffies.
341 * @policy: cpufreq policy to enable fast frequency switching for.
342 * @freqs: contain details of the frequency update.
343 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
344 *
345 * This function calls the transition notifiers and adjust_jiffies().
346 *
347 * It is called twice on all CPU frequency changes that have external effects.
348 */
349static void cpufreq_notify_transition(struct cpufreq_policy *policy,
350 struct cpufreq_freqs *freqs,
351 unsigned int state)
352{
353 int cpu;
354
355 BUG_ON(irqs_disabled());
356
357 if (cpufreq_disabled())
358 return;
359
360 freqs->policy = policy;
361 freqs->flags = cpufreq_driver->flags;
362 pr_debug("notification %u of frequency transition to %u kHz\n",
363 state, freqs->new);
364
365 switch (state) {
366 case CPUFREQ_PRECHANGE:
367 /*
368 * Detect if the driver reported a value as "old frequency"
369 * which is not equal to what the cpufreq core thinks is
370 * "old frequency".
371 */
372 if (policy->cur && policy->cur != freqs->old) {
373 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
374 freqs->old, policy->cur);
375 freqs->old = policy->cur;
376 }
377
378 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
379 CPUFREQ_PRECHANGE, freqs);
380
381 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
382 break;
383
384 case CPUFREQ_POSTCHANGE:
385 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
386 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
387 cpumask_pr_args(policy->cpus));
388
389 for_each_cpu(cpu, policy->cpus)
390 trace_cpu_frequency(freqs->new, cpu);
391
392 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
393 CPUFREQ_POSTCHANGE, freqs);
394
395 cpufreq_stats_record_transition(policy, freqs->new);
396 policy->cur = freqs->new;
397 }
398}
399
400/* Do post notifications when there are chances that transition has failed */
401static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
402 struct cpufreq_freqs *freqs, int transition_failed)
403{
404 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
405 if (!transition_failed)
406 return;
407
408 swap(freqs->old, freqs->new);
409 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
410 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
411}
412
413void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
414 struct cpufreq_freqs *freqs)
415{
416
417 /*
418 * Catch double invocations of _begin() which lead to self-deadlock.
419 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
420 * doesn't invoke _begin() on their behalf, and hence the chances of
421 * double invocations are very low. Moreover, there are scenarios
422 * where these checks can emit false-positive warnings in these
423 * drivers; so we avoid that by skipping them altogether.
424 */
425 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
426 && current == policy->transition_task);
427
428wait:
429 wait_event(policy->transition_wait, !policy->transition_ongoing);
430
431 spin_lock(&policy->transition_lock);
432
433 if (unlikely(policy->transition_ongoing)) {
434 spin_unlock(&policy->transition_lock);
435 goto wait;
436 }
437
438 policy->transition_ongoing = true;
439 policy->transition_task = current;
440
441 spin_unlock(&policy->transition_lock);
442
443 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
444}
445EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
446
447void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
448 struct cpufreq_freqs *freqs, int transition_failed)
449{
450 if (WARN_ON(!policy->transition_ongoing))
451 return;
452
453 cpufreq_notify_post_transition(policy, freqs, transition_failed);
454
455 arch_set_freq_scale(policy->related_cpus,
456 policy->cur,
457 arch_scale_freq_ref(policy->cpu));
458
459 spin_lock(&policy->transition_lock);
460 policy->transition_ongoing = false;
461 policy->transition_task = NULL;
462 spin_unlock(&policy->transition_lock);
463
464 wake_up(&policy->transition_wait);
465}
466EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
467
468/*
469 * Fast frequency switching status count. Positive means "enabled", negative
470 * means "disabled" and 0 means "not decided yet".
471 */
472static int cpufreq_fast_switch_count;
473static DEFINE_MUTEX(cpufreq_fast_switch_lock);
474
475static void cpufreq_list_transition_notifiers(void)
476{
477 struct notifier_block *nb;
478
479 pr_info("Registered transition notifiers:\n");
480
481 mutex_lock(&cpufreq_transition_notifier_list.mutex);
482
483 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
484 pr_info("%pS\n", nb->notifier_call);
485
486 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
487}
488
489/**
490 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
491 * @policy: cpufreq policy to enable fast frequency switching for.
492 *
493 * Try to enable fast frequency switching for @policy.
494 *
495 * The attempt will fail if there is at least one transition notifier registered
496 * at this point, as fast frequency switching is quite fundamentally at odds
497 * with transition notifiers. Thus if successful, it will make registration of
498 * transition notifiers fail going forward.
499 */
500void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
501{
502 lockdep_assert_held(&policy->rwsem);
503
504 if (!policy->fast_switch_possible)
505 return;
506
507 mutex_lock(&cpufreq_fast_switch_lock);
508 if (cpufreq_fast_switch_count >= 0) {
509 cpufreq_fast_switch_count++;
510 policy->fast_switch_enabled = true;
511 } else {
512 pr_warn("CPU%u: Fast frequency switching not enabled\n",
513 policy->cpu);
514 cpufreq_list_transition_notifiers();
515 }
516 mutex_unlock(&cpufreq_fast_switch_lock);
517}
518EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
519
520/**
521 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
522 * @policy: cpufreq policy to disable fast frequency switching for.
523 */
524void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
525{
526 mutex_lock(&cpufreq_fast_switch_lock);
527 if (policy->fast_switch_enabled) {
528 policy->fast_switch_enabled = false;
529 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
530 cpufreq_fast_switch_count--;
531 }
532 mutex_unlock(&cpufreq_fast_switch_lock);
533}
534EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
535
536static unsigned int __resolve_freq(struct cpufreq_policy *policy,
537 unsigned int target_freq, unsigned int relation)
538{
539 unsigned int idx;
540
541 target_freq = clamp_val(target_freq, policy->min, policy->max);
542
543 if (!policy->freq_table)
544 return target_freq;
545
546 idx = cpufreq_frequency_table_target(policy, target_freq, relation);
547 policy->cached_resolved_idx = idx;
548 policy->cached_target_freq = target_freq;
549 return policy->freq_table[idx].frequency;
550}
551
552/**
553 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
554 * one.
555 * @policy: associated policy to interrogate
556 * @target_freq: target frequency to resolve.
557 *
558 * The target to driver frequency mapping is cached in the policy.
559 *
560 * Return: Lowest driver-supported frequency greater than or equal to the
561 * given target_freq, subject to policy (min/max) and driver limitations.
562 */
563unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
564 unsigned int target_freq)
565{
566 return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_LE);
567}
568EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
569
570unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
571{
572 unsigned int latency;
573
574 if (policy->transition_delay_us)
575 return policy->transition_delay_us;
576
577 latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
578 if (latency)
579 /* Give a 50% breathing room between updates */
580 return latency + (latency >> 1);
581
582 return USEC_PER_MSEC;
583}
584EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
585
586/*********************************************************************
587 * SYSFS INTERFACE *
588 *********************************************************************/
589static ssize_t show_boost(struct kobject *kobj,
590 struct kobj_attribute *attr, char *buf)
591{
592 return sysfs_emit(buf, "%d\n", cpufreq_driver->boost_enabled);
593}
594
595static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
596 const char *buf, size_t count)
597{
598 bool enable;
599
600 if (kstrtobool(buf, &enable))
601 return -EINVAL;
602
603 if (cpufreq_boost_trigger_state(enable)) {
604 pr_err("%s: Cannot %s BOOST!\n",
605 __func__, enable ? "enable" : "disable");
606 return -EINVAL;
607 }
608
609 pr_debug("%s: cpufreq BOOST %s\n",
610 __func__, enable ? "enabled" : "disabled");
611
612 return count;
613}
614define_one_global_rw(boost);
615
616static ssize_t show_local_boost(struct cpufreq_policy *policy, char *buf)
617{
618 return sysfs_emit(buf, "%d\n", policy->boost_enabled);
619}
620
621static ssize_t store_local_boost(struct cpufreq_policy *policy,
622 const char *buf, size_t count)
623{
624 int ret;
625 bool enable;
626
627 if (kstrtobool(buf, &enable))
628 return -EINVAL;
629
630 if (!cpufreq_driver->boost_enabled)
631 return -EINVAL;
632
633 if (policy->boost_enabled == enable)
634 return count;
635
636 policy->boost_enabled = enable;
637
638 cpus_read_lock();
639 ret = cpufreq_driver->set_boost(policy, enable);
640 cpus_read_unlock();
641
642 if (ret) {
643 policy->boost_enabled = !policy->boost_enabled;
644 return ret;
645 }
646
647 return count;
648}
649
650static struct freq_attr local_boost = __ATTR(boost, 0644, show_local_boost, store_local_boost);
651
652static struct cpufreq_governor *find_governor(const char *str_governor)
653{
654 struct cpufreq_governor *t;
655
656 for_each_governor(t)
657 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
658 return t;
659
660 return NULL;
661}
662
663static struct cpufreq_governor *get_governor(const char *str_governor)
664{
665 struct cpufreq_governor *t;
666
667 mutex_lock(&cpufreq_governor_mutex);
668 t = find_governor(str_governor);
669 if (!t)
670 goto unlock;
671
672 if (!try_module_get(t->owner))
673 t = NULL;
674
675unlock:
676 mutex_unlock(&cpufreq_governor_mutex);
677
678 return t;
679}
680
681static unsigned int cpufreq_parse_policy(char *str_governor)
682{
683 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
684 return CPUFREQ_POLICY_PERFORMANCE;
685
686 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
687 return CPUFREQ_POLICY_POWERSAVE;
688
689 return CPUFREQ_POLICY_UNKNOWN;
690}
691
692/**
693 * cpufreq_parse_governor - parse a governor string only for has_target()
694 * @str_governor: Governor name.
695 */
696static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
697{
698 struct cpufreq_governor *t;
699
700 t = get_governor(str_governor);
701 if (t)
702 return t;
703
704 if (request_module("cpufreq_%s", str_governor))
705 return NULL;
706
707 return get_governor(str_governor);
708}
709
710/*
711 * cpufreq_per_cpu_attr_read() / show_##file_name() -
712 * print out cpufreq information
713 *
714 * Write out information from cpufreq_driver->policy[cpu]; object must be
715 * "unsigned int".
716 */
717
718#define show_one(file_name, object) \
719static ssize_t show_##file_name \
720(struct cpufreq_policy *policy, char *buf) \
721{ \
722 return sysfs_emit(buf, "%u\n", policy->object); \
723}
724
725show_one(cpuinfo_min_freq, cpuinfo.min_freq);
726show_one(cpuinfo_max_freq, cpuinfo.max_freq);
727show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
728show_one(scaling_min_freq, min);
729show_one(scaling_max_freq, max);
730
731__weak unsigned int arch_freq_get_on_cpu(int cpu)
732{
733 return 0;
734}
735
736static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
737{
738 ssize_t ret;
739 unsigned int freq;
740
741 freq = arch_freq_get_on_cpu(policy->cpu);
742 if (freq)
743 ret = sysfs_emit(buf, "%u\n", freq);
744 else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
745 ret = sysfs_emit(buf, "%u\n", cpufreq_driver->get(policy->cpu));
746 else
747 ret = sysfs_emit(buf, "%u\n", policy->cur);
748 return ret;
749}
750
751/*
752 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
753 */
754#define store_one(file_name, object) \
755static ssize_t store_##file_name \
756(struct cpufreq_policy *policy, const char *buf, size_t count) \
757{ \
758 unsigned long val; \
759 int ret; \
760 \
761 ret = kstrtoul(buf, 0, &val); \
762 if (ret) \
763 return ret; \
764 \
765 ret = freq_qos_update_request(policy->object##_freq_req, val);\
766 return ret >= 0 ? count : ret; \
767}
768
769store_one(scaling_min_freq, min);
770store_one(scaling_max_freq, max);
771
772/*
773 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
774 */
775static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
776 char *buf)
777{
778 unsigned int cur_freq = __cpufreq_get(policy);
779
780 if (cur_freq)
781 return sysfs_emit(buf, "%u\n", cur_freq);
782
783 return sysfs_emit(buf, "<unknown>\n");
784}
785
786/*
787 * show_scaling_governor - show the current policy for the specified CPU
788 */
789static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
790{
791 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
792 return sysfs_emit(buf, "powersave\n");
793 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
794 return sysfs_emit(buf, "performance\n");
795 else if (policy->governor)
796 return sysfs_emit(buf, "%s\n", policy->governor->name);
797 return -EINVAL;
798}
799
800/*
801 * store_scaling_governor - store policy for the specified CPU
802 */
803static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
804 const char *buf, size_t count)
805{
806 char str_governor[16];
807 int ret;
808
809 ret = sscanf(buf, "%15s", str_governor);
810 if (ret != 1)
811 return -EINVAL;
812
813 if (cpufreq_driver->setpolicy) {
814 unsigned int new_pol;
815
816 new_pol = cpufreq_parse_policy(str_governor);
817 if (!new_pol)
818 return -EINVAL;
819
820 ret = cpufreq_set_policy(policy, NULL, new_pol);
821 } else {
822 struct cpufreq_governor *new_gov;
823
824 new_gov = cpufreq_parse_governor(str_governor);
825 if (!new_gov)
826 return -EINVAL;
827
828 ret = cpufreq_set_policy(policy, new_gov,
829 CPUFREQ_POLICY_UNKNOWN);
830
831 module_put(new_gov->owner);
832 }
833
834 return ret ? ret : count;
835}
836
837/*
838 * show_scaling_driver - show the cpufreq driver currently loaded
839 */
840static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
841{
842 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
843}
844
845/*
846 * show_scaling_available_governors - show the available CPUfreq governors
847 */
848static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
849 char *buf)
850{
851 ssize_t i = 0;
852 struct cpufreq_governor *t;
853
854 if (!has_target()) {
855 i += sysfs_emit(buf, "performance powersave");
856 goto out;
857 }
858
859 mutex_lock(&cpufreq_governor_mutex);
860 for_each_governor(t) {
861 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
862 - (CPUFREQ_NAME_LEN + 2)))
863 break;
864 i += sysfs_emit_at(buf, i, "%s ", t->name);
865 }
866 mutex_unlock(&cpufreq_governor_mutex);
867out:
868 i += sysfs_emit_at(buf, i, "\n");
869 return i;
870}
871
872ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
873{
874 ssize_t i = 0;
875 unsigned int cpu;
876
877 for_each_cpu(cpu, mask) {
878 i += sysfs_emit_at(buf, i, "%u ", cpu);
879 if (i >= (PAGE_SIZE - 5))
880 break;
881 }
882
883 /* Remove the extra space at the end */
884 i--;
885
886 i += sysfs_emit_at(buf, i, "\n");
887 return i;
888}
889EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
890
891/*
892 * show_related_cpus - show the CPUs affected by each transition even if
893 * hw coordination is in use
894 */
895static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
896{
897 return cpufreq_show_cpus(policy->related_cpus, buf);
898}
899
900/*
901 * show_affected_cpus - show the CPUs affected by each transition
902 */
903static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
904{
905 return cpufreq_show_cpus(policy->cpus, buf);
906}
907
908static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
909 const char *buf, size_t count)
910{
911 unsigned int freq = 0;
912 unsigned int ret;
913
914 if (!policy->governor || !policy->governor->store_setspeed)
915 return -EINVAL;
916
917 ret = sscanf(buf, "%u", &freq);
918 if (ret != 1)
919 return -EINVAL;
920
921 policy->governor->store_setspeed(policy, freq);
922
923 return count;
924}
925
926static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
927{
928 if (!policy->governor || !policy->governor->show_setspeed)
929 return sysfs_emit(buf, "<unsupported>\n");
930
931 return policy->governor->show_setspeed(policy, buf);
932}
933
934/*
935 * show_bios_limit - show the current cpufreq HW/BIOS limitation
936 */
937static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
938{
939 unsigned int limit;
940 int ret;
941 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
942 if (!ret)
943 return sysfs_emit(buf, "%u\n", limit);
944 return sysfs_emit(buf, "%u\n", policy->cpuinfo.max_freq);
945}
946
947cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
948cpufreq_freq_attr_ro(cpuinfo_min_freq);
949cpufreq_freq_attr_ro(cpuinfo_max_freq);
950cpufreq_freq_attr_ro(cpuinfo_transition_latency);
951cpufreq_freq_attr_ro(scaling_available_governors);
952cpufreq_freq_attr_ro(scaling_driver);
953cpufreq_freq_attr_ro(scaling_cur_freq);
954cpufreq_freq_attr_ro(bios_limit);
955cpufreq_freq_attr_ro(related_cpus);
956cpufreq_freq_attr_ro(affected_cpus);
957cpufreq_freq_attr_rw(scaling_min_freq);
958cpufreq_freq_attr_rw(scaling_max_freq);
959cpufreq_freq_attr_rw(scaling_governor);
960cpufreq_freq_attr_rw(scaling_setspeed);
961
962static struct attribute *cpufreq_attrs[] = {
963 &cpuinfo_min_freq.attr,
964 &cpuinfo_max_freq.attr,
965 &cpuinfo_transition_latency.attr,
966 &scaling_min_freq.attr,
967 &scaling_max_freq.attr,
968 &affected_cpus.attr,
969 &related_cpus.attr,
970 &scaling_governor.attr,
971 &scaling_driver.attr,
972 &scaling_available_governors.attr,
973 &scaling_setspeed.attr,
974 NULL
975};
976ATTRIBUTE_GROUPS(cpufreq);
977
978#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
979#define to_attr(a) container_of(a, struct freq_attr, attr)
980
981static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
982{
983 struct cpufreq_policy *policy = to_policy(kobj);
984 struct freq_attr *fattr = to_attr(attr);
985 ssize_t ret = -EBUSY;
986
987 if (!fattr->show)
988 return -EIO;
989
990 down_read(&policy->rwsem);
991 if (likely(!policy_is_inactive(policy)))
992 ret = fattr->show(policy, buf);
993 up_read(&policy->rwsem);
994
995 return ret;
996}
997
998static ssize_t store(struct kobject *kobj, struct attribute *attr,
999 const char *buf, size_t count)
1000{
1001 struct cpufreq_policy *policy = to_policy(kobj);
1002 struct freq_attr *fattr = to_attr(attr);
1003 ssize_t ret = -EBUSY;
1004
1005 if (!fattr->store)
1006 return -EIO;
1007
1008 down_write(&policy->rwsem);
1009 if (likely(!policy_is_inactive(policy)))
1010 ret = fattr->store(policy, buf, count);
1011 up_write(&policy->rwsem);
1012
1013 return ret;
1014}
1015
1016static void cpufreq_sysfs_release(struct kobject *kobj)
1017{
1018 struct cpufreq_policy *policy = to_policy(kobj);
1019 pr_debug("last reference is dropped\n");
1020 complete(&policy->kobj_unregister);
1021}
1022
1023static const struct sysfs_ops sysfs_ops = {
1024 .show = show,
1025 .store = store,
1026};
1027
1028static const struct kobj_type ktype_cpufreq = {
1029 .sysfs_ops = &sysfs_ops,
1030 .default_groups = cpufreq_groups,
1031 .release = cpufreq_sysfs_release,
1032};
1033
1034static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
1035 struct device *dev)
1036{
1037 if (unlikely(!dev))
1038 return;
1039
1040 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1041 return;
1042
1043 dev_dbg(dev, "%s: Adding symlink\n", __func__);
1044 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1045 dev_err(dev, "cpufreq symlink creation failed\n");
1046}
1047
1048static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu,
1049 struct device *dev)
1050{
1051 dev_dbg(dev, "%s: Removing symlink\n", __func__);
1052 sysfs_remove_link(&dev->kobj, "cpufreq");
1053 cpumask_clear_cpu(cpu, policy->real_cpus);
1054}
1055
1056static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1057{
1058 struct freq_attr **drv_attr;
1059 int ret = 0;
1060
1061 /* set up files for this cpu device */
1062 drv_attr = cpufreq_driver->attr;
1063 while (drv_attr && *drv_attr) {
1064 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1065 if (ret)
1066 return ret;
1067 drv_attr++;
1068 }
1069 if (cpufreq_driver->get) {
1070 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1071 if (ret)
1072 return ret;
1073 }
1074
1075 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1076 if (ret)
1077 return ret;
1078
1079 if (cpufreq_driver->bios_limit) {
1080 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1081 if (ret)
1082 return ret;
1083 }
1084
1085 if (cpufreq_boost_supported()) {
1086 ret = sysfs_create_file(&policy->kobj, &local_boost.attr);
1087 if (ret)
1088 return ret;
1089 }
1090
1091 return 0;
1092}
1093
1094static int cpufreq_init_policy(struct cpufreq_policy *policy)
1095{
1096 struct cpufreq_governor *gov = NULL;
1097 unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
1098 int ret;
1099
1100 if (has_target()) {
1101 /* Update policy governor to the one used before hotplug. */
1102 gov = get_governor(policy->last_governor);
1103 if (gov) {
1104 pr_debug("Restoring governor %s for cpu %d\n",
1105 gov->name, policy->cpu);
1106 } else {
1107 gov = get_governor(default_governor);
1108 }
1109
1110 if (!gov) {
1111 gov = cpufreq_default_governor();
1112 __module_get(gov->owner);
1113 }
1114
1115 } else {
1116
1117 /* Use the default policy if there is no last_policy. */
1118 if (policy->last_policy) {
1119 pol = policy->last_policy;
1120 } else {
1121 pol = cpufreq_parse_policy(default_governor);
1122 /*
1123 * In case the default governor is neither "performance"
1124 * nor "powersave", fall back to the initial policy
1125 * value set by the driver.
1126 */
1127 if (pol == CPUFREQ_POLICY_UNKNOWN)
1128 pol = policy->policy;
1129 }
1130 if (pol != CPUFREQ_POLICY_PERFORMANCE &&
1131 pol != CPUFREQ_POLICY_POWERSAVE)
1132 return -ENODATA;
1133 }
1134
1135 ret = cpufreq_set_policy(policy, gov, pol);
1136 if (gov)
1137 module_put(gov->owner);
1138
1139 return ret;
1140}
1141
1142static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1143{
1144 int ret = 0;
1145
1146 /* Has this CPU been taken care of already? */
1147 if (cpumask_test_cpu(cpu, policy->cpus))
1148 return 0;
1149
1150 down_write(&policy->rwsem);
1151 if (has_target())
1152 cpufreq_stop_governor(policy);
1153
1154 cpumask_set_cpu(cpu, policy->cpus);
1155
1156 if (has_target()) {
1157 ret = cpufreq_start_governor(policy);
1158 if (ret)
1159 pr_err("%s: Failed to start governor\n", __func__);
1160 }
1161 up_write(&policy->rwsem);
1162 return ret;
1163}
1164
1165void refresh_frequency_limits(struct cpufreq_policy *policy)
1166{
1167 if (!policy_is_inactive(policy)) {
1168 pr_debug("updating policy for CPU %u\n", policy->cpu);
1169
1170 cpufreq_set_policy(policy, policy->governor, policy->policy);
1171 }
1172}
1173EXPORT_SYMBOL(refresh_frequency_limits);
1174
1175static void handle_update(struct work_struct *work)
1176{
1177 struct cpufreq_policy *policy =
1178 container_of(work, struct cpufreq_policy, update);
1179
1180 pr_debug("handle_update for cpu %u called\n", policy->cpu);
1181 down_write(&policy->rwsem);
1182 refresh_frequency_limits(policy);
1183 up_write(&policy->rwsem);
1184}
1185
1186static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1187 void *data)
1188{
1189 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1190
1191 schedule_work(&policy->update);
1192 return 0;
1193}
1194
1195static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1196 void *data)
1197{
1198 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1199
1200 schedule_work(&policy->update);
1201 return 0;
1202}
1203
1204static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1205{
1206 struct kobject *kobj;
1207 struct completion *cmp;
1208
1209 down_write(&policy->rwsem);
1210 cpufreq_stats_free_table(policy);
1211 kobj = &policy->kobj;
1212 cmp = &policy->kobj_unregister;
1213 up_write(&policy->rwsem);
1214 kobject_put(kobj);
1215
1216 /*
1217 * We need to make sure that the underlying kobj is
1218 * actually not referenced anymore by anybody before we
1219 * proceed with unloading.
1220 */
1221 pr_debug("waiting for dropping of refcount\n");
1222 wait_for_completion(cmp);
1223 pr_debug("wait complete\n");
1224}
1225
1226static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1227{
1228 struct cpufreq_policy *policy;
1229 struct device *dev = get_cpu_device(cpu);
1230 int ret;
1231
1232 if (!dev)
1233 return NULL;
1234
1235 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1236 if (!policy)
1237 return NULL;
1238
1239 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1240 goto err_free_policy;
1241
1242 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1243 goto err_free_cpumask;
1244
1245 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1246 goto err_free_rcpumask;
1247
1248 init_completion(&policy->kobj_unregister);
1249 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1250 cpufreq_global_kobject, "policy%u", cpu);
1251 if (ret) {
1252 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1253 /*
1254 * The entire policy object will be freed below, but the extra
1255 * memory allocated for the kobject name needs to be freed by
1256 * releasing the kobject.
1257 */
1258 kobject_put(&policy->kobj);
1259 goto err_free_real_cpus;
1260 }
1261
1262 freq_constraints_init(&policy->constraints);
1263
1264 policy->nb_min.notifier_call = cpufreq_notifier_min;
1265 policy->nb_max.notifier_call = cpufreq_notifier_max;
1266
1267 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1268 &policy->nb_min);
1269 if (ret) {
1270 dev_err(dev, "Failed to register MIN QoS notifier: %d (CPU%u)\n",
1271 ret, cpu);
1272 goto err_kobj_remove;
1273 }
1274
1275 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1276 &policy->nb_max);
1277 if (ret) {
1278 dev_err(dev, "Failed to register MAX QoS notifier: %d (CPU%u)\n",
1279 ret, cpu);
1280 goto err_min_qos_notifier;
1281 }
1282
1283 INIT_LIST_HEAD(&policy->policy_list);
1284 init_rwsem(&policy->rwsem);
1285 spin_lock_init(&policy->transition_lock);
1286 init_waitqueue_head(&policy->transition_wait);
1287 INIT_WORK(&policy->update, handle_update);
1288
1289 policy->cpu = cpu;
1290 return policy;
1291
1292err_min_qos_notifier:
1293 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1294 &policy->nb_min);
1295err_kobj_remove:
1296 cpufreq_policy_put_kobj(policy);
1297err_free_real_cpus:
1298 free_cpumask_var(policy->real_cpus);
1299err_free_rcpumask:
1300 free_cpumask_var(policy->related_cpus);
1301err_free_cpumask:
1302 free_cpumask_var(policy->cpus);
1303err_free_policy:
1304 kfree(policy);
1305
1306 return NULL;
1307}
1308
1309static void cpufreq_policy_free(struct cpufreq_policy *policy)
1310{
1311 unsigned long flags;
1312 int cpu;
1313
1314 /*
1315 * The callers must ensure the policy is inactive by now, to avoid any
1316 * races with show()/store() callbacks.
1317 */
1318 if (unlikely(!policy_is_inactive(policy)))
1319 pr_warn("%s: Freeing active policy\n", __func__);
1320
1321 /* Remove policy from list */
1322 write_lock_irqsave(&cpufreq_driver_lock, flags);
1323 list_del(&policy->policy_list);
1324
1325 for_each_cpu(cpu, policy->related_cpus)
1326 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1327 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1328
1329 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1330 &policy->nb_max);
1331 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1332 &policy->nb_min);
1333
1334 /* Cancel any pending policy->update work before freeing the policy. */
1335 cancel_work_sync(&policy->update);
1336
1337 if (policy->max_freq_req) {
1338 /*
1339 * Remove max_freq_req after sending CPUFREQ_REMOVE_POLICY
1340 * notification, since CPUFREQ_CREATE_POLICY notification was
1341 * sent after adding max_freq_req earlier.
1342 */
1343 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1344 CPUFREQ_REMOVE_POLICY, policy);
1345 freq_qos_remove_request(policy->max_freq_req);
1346 }
1347
1348 freq_qos_remove_request(policy->min_freq_req);
1349 kfree(policy->min_freq_req);
1350
1351 cpufreq_policy_put_kobj(policy);
1352 free_cpumask_var(policy->real_cpus);
1353 free_cpumask_var(policy->related_cpus);
1354 free_cpumask_var(policy->cpus);
1355 kfree(policy);
1356}
1357
1358static int cpufreq_online(unsigned int cpu)
1359{
1360 struct cpufreq_policy *policy;
1361 bool new_policy;
1362 unsigned long flags;
1363 unsigned int j;
1364 int ret;
1365
1366 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1367
1368 /* Check if this CPU already has a policy to manage it */
1369 policy = per_cpu(cpufreq_cpu_data, cpu);
1370 if (policy) {
1371 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1372 if (!policy_is_inactive(policy))
1373 return cpufreq_add_policy_cpu(policy, cpu);
1374
1375 /* This is the only online CPU for the policy. Start over. */
1376 new_policy = false;
1377 down_write(&policy->rwsem);
1378 policy->cpu = cpu;
1379 policy->governor = NULL;
1380 } else {
1381 new_policy = true;
1382 policy = cpufreq_policy_alloc(cpu);
1383 if (!policy)
1384 return -ENOMEM;
1385 down_write(&policy->rwsem);
1386 }
1387
1388 if (!new_policy && cpufreq_driver->online) {
1389 /* Recover policy->cpus using related_cpus */
1390 cpumask_copy(policy->cpus, policy->related_cpus);
1391
1392 ret = cpufreq_driver->online(policy);
1393 if (ret) {
1394 pr_debug("%s: %d: initialization failed\n", __func__,
1395 __LINE__);
1396 goto out_exit_policy;
1397 }
1398 } else {
1399 cpumask_copy(policy->cpus, cpumask_of(cpu));
1400
1401 /*
1402 * Call driver. From then on the cpufreq must be able
1403 * to accept all calls to ->verify and ->setpolicy for this CPU.
1404 */
1405 ret = cpufreq_driver->init(policy);
1406 if (ret) {
1407 pr_debug("%s: %d: initialization failed\n", __func__,
1408 __LINE__);
1409 goto out_free_policy;
1410 }
1411
1412 /* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
1413 if (cpufreq_boost_enabled() && policy_has_boost_freq(policy))
1414 policy->boost_enabled = true;
1415
1416 /*
1417 * The initialization has succeeded and the policy is online.
1418 * If there is a problem with its frequency table, take it
1419 * offline and drop it.
1420 */
1421 ret = cpufreq_table_validate_and_sort(policy);
1422 if (ret)
1423 goto out_offline_policy;
1424
1425 /* related_cpus should at least include policy->cpus. */
1426 cpumask_copy(policy->related_cpus, policy->cpus);
1427 }
1428
1429 /*
1430 * affected cpus must always be the one, which are online. We aren't
1431 * managing offline cpus here.
1432 */
1433 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1434
1435 if (new_policy) {
1436 for_each_cpu(j, policy->related_cpus) {
1437 per_cpu(cpufreq_cpu_data, j) = policy;
1438 add_cpu_dev_symlink(policy, j, get_cpu_device(j));
1439 }
1440
1441 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1442 GFP_KERNEL);
1443 if (!policy->min_freq_req) {
1444 ret = -ENOMEM;
1445 goto out_destroy_policy;
1446 }
1447
1448 ret = freq_qos_add_request(&policy->constraints,
1449 policy->min_freq_req, FREQ_QOS_MIN,
1450 FREQ_QOS_MIN_DEFAULT_VALUE);
1451 if (ret < 0) {
1452 /*
1453 * So we don't call freq_qos_remove_request() for an
1454 * uninitialized request.
1455 */
1456 kfree(policy->min_freq_req);
1457 policy->min_freq_req = NULL;
1458 goto out_destroy_policy;
1459 }
1460
1461 /*
1462 * This must be initialized right here to avoid calling
1463 * freq_qos_remove_request() on uninitialized request in case
1464 * of errors.
1465 */
1466 policy->max_freq_req = policy->min_freq_req + 1;
1467
1468 ret = freq_qos_add_request(&policy->constraints,
1469 policy->max_freq_req, FREQ_QOS_MAX,
1470 FREQ_QOS_MAX_DEFAULT_VALUE);
1471 if (ret < 0) {
1472 policy->max_freq_req = NULL;
1473 goto out_destroy_policy;
1474 }
1475
1476 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1477 CPUFREQ_CREATE_POLICY, policy);
1478 }
1479
1480 if (cpufreq_driver->get && has_target()) {
1481 policy->cur = cpufreq_driver->get(policy->cpu);
1482 if (!policy->cur) {
1483 ret = -EIO;
1484 pr_err("%s: ->get() failed\n", __func__);
1485 goto out_destroy_policy;
1486 }
1487 }
1488
1489 /*
1490 * Sometimes boot loaders set CPU frequency to a value outside of
1491 * frequency table present with cpufreq core. In such cases CPU might be
1492 * unstable if it has to run on that frequency for long duration of time
1493 * and so its better to set it to a frequency which is specified in
1494 * freq-table. This also makes cpufreq stats inconsistent as
1495 * cpufreq-stats would fail to register because current frequency of CPU
1496 * isn't found in freq-table.
1497 *
1498 * Because we don't want this change to effect boot process badly, we go
1499 * for the next freq which is >= policy->cur ('cur' must be set by now,
1500 * otherwise we will end up setting freq to lowest of the table as 'cur'
1501 * is initialized to zero).
1502 *
1503 * We are passing target-freq as "policy->cur - 1" otherwise
1504 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1505 * equal to target-freq.
1506 */
1507 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1508 && has_target()) {
1509 unsigned int old_freq = policy->cur;
1510
1511 /* Are we running at unknown frequency ? */
1512 ret = cpufreq_frequency_table_get_index(policy, old_freq);
1513 if (ret == -EINVAL) {
1514 ret = __cpufreq_driver_target(policy, old_freq - 1,
1515 CPUFREQ_RELATION_L);
1516
1517 /*
1518 * Reaching here after boot in a few seconds may not
1519 * mean that system will remain stable at "unknown"
1520 * frequency for longer duration. Hence, a BUG_ON().
1521 */
1522 BUG_ON(ret);
1523 pr_info("%s: CPU%d: Running at unlisted initial frequency: %u kHz, changing to: %u kHz\n",
1524 __func__, policy->cpu, old_freq, policy->cur);
1525 }
1526 }
1527
1528 if (new_policy) {
1529 ret = cpufreq_add_dev_interface(policy);
1530 if (ret)
1531 goto out_destroy_policy;
1532
1533 cpufreq_stats_create_table(policy);
1534
1535 write_lock_irqsave(&cpufreq_driver_lock, flags);
1536 list_add(&policy->policy_list, &cpufreq_policy_list);
1537 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1538
1539 /*
1540 * Register with the energy model before
1541 * sugov_eas_rebuild_sd() is called, which will result
1542 * in rebuilding of the sched domains, which should only be done
1543 * once the energy model is properly initialized for the policy
1544 * first.
1545 *
1546 * Also, this should be called before the policy is registered
1547 * with cooling framework.
1548 */
1549 if (cpufreq_driver->register_em)
1550 cpufreq_driver->register_em(policy);
1551 }
1552
1553 ret = cpufreq_init_policy(policy);
1554 if (ret) {
1555 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1556 __func__, cpu, ret);
1557 goto out_destroy_policy;
1558 }
1559
1560 up_write(&policy->rwsem);
1561
1562 kobject_uevent(&policy->kobj, KOBJ_ADD);
1563
1564 /* Callback for handling stuff after policy is ready */
1565 if (cpufreq_driver->ready)
1566 cpufreq_driver->ready(policy);
1567
1568 /* Register cpufreq cooling only for a new policy */
1569 if (new_policy && cpufreq_thermal_control_enabled(cpufreq_driver))
1570 policy->cdev = of_cpufreq_cooling_register(policy);
1571
1572 pr_debug("initialization complete\n");
1573
1574 return 0;
1575
1576out_destroy_policy:
1577 for_each_cpu(j, policy->real_cpus)
1578 remove_cpu_dev_symlink(policy, j, get_cpu_device(j));
1579
1580out_offline_policy:
1581 if (cpufreq_driver->offline)
1582 cpufreq_driver->offline(policy);
1583
1584out_exit_policy:
1585 if (cpufreq_driver->exit)
1586 cpufreq_driver->exit(policy);
1587
1588out_free_policy:
1589 cpumask_clear(policy->cpus);
1590 up_write(&policy->rwsem);
1591
1592 cpufreq_policy_free(policy);
1593 return ret;
1594}
1595
1596/**
1597 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1598 * @dev: CPU device.
1599 * @sif: Subsystem interface structure pointer (not used)
1600 */
1601static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1602{
1603 struct cpufreq_policy *policy;
1604 unsigned cpu = dev->id;
1605 int ret;
1606
1607 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1608
1609 if (cpu_online(cpu)) {
1610 ret = cpufreq_online(cpu);
1611 if (ret)
1612 return ret;
1613 }
1614
1615 /* Create sysfs link on CPU registration */
1616 policy = per_cpu(cpufreq_cpu_data, cpu);
1617 if (policy)
1618 add_cpu_dev_symlink(policy, cpu, dev);
1619
1620 return 0;
1621}
1622
1623static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy)
1624{
1625 int ret;
1626
1627 if (has_target())
1628 cpufreq_stop_governor(policy);
1629
1630 cpumask_clear_cpu(cpu, policy->cpus);
1631
1632 if (!policy_is_inactive(policy)) {
1633 /* Nominate a new CPU if necessary. */
1634 if (cpu == policy->cpu)
1635 policy->cpu = cpumask_any(policy->cpus);
1636
1637 /* Start the governor again for the active policy. */
1638 if (has_target()) {
1639 ret = cpufreq_start_governor(policy);
1640 if (ret)
1641 pr_err("%s: Failed to start governor\n", __func__);
1642 }
1643
1644 return;
1645 }
1646
1647 if (has_target())
1648 strscpy(policy->last_governor, policy->governor->name,
1649 CPUFREQ_NAME_LEN);
1650 else
1651 policy->last_policy = policy->policy;
1652
1653 if (has_target())
1654 cpufreq_exit_governor(policy);
1655
1656 /*
1657 * Perform the ->offline() during light-weight tear-down, as
1658 * that allows fast recovery when the CPU comes back.
1659 */
1660 if (cpufreq_driver->offline) {
1661 cpufreq_driver->offline(policy);
1662 return;
1663 }
1664
1665 if (cpufreq_driver->exit)
1666 cpufreq_driver->exit(policy);
1667
1668 policy->freq_table = NULL;
1669}
1670
1671static int cpufreq_offline(unsigned int cpu)
1672{
1673 struct cpufreq_policy *policy;
1674
1675 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1676
1677 policy = cpufreq_cpu_get_raw(cpu);
1678 if (!policy) {
1679 pr_debug("%s: No cpu_data found\n", __func__);
1680 return 0;
1681 }
1682
1683 down_write(&policy->rwsem);
1684
1685 __cpufreq_offline(cpu, policy);
1686
1687 up_write(&policy->rwsem);
1688 return 0;
1689}
1690
1691/*
1692 * cpufreq_remove_dev - remove a CPU device
1693 *
1694 * Removes the cpufreq interface for a CPU device.
1695 */
1696static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1697{
1698 unsigned int cpu = dev->id;
1699 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1700
1701 if (!policy)
1702 return;
1703
1704 down_write(&policy->rwsem);
1705
1706 if (cpu_online(cpu))
1707 __cpufreq_offline(cpu, policy);
1708
1709 remove_cpu_dev_symlink(policy, cpu, dev);
1710
1711 if (!cpumask_empty(policy->real_cpus)) {
1712 up_write(&policy->rwsem);
1713 return;
1714 }
1715
1716 /*
1717 * Unregister cpufreq cooling once all the CPUs of the policy are
1718 * removed.
1719 */
1720 if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1721 cpufreq_cooling_unregister(policy->cdev);
1722 policy->cdev = NULL;
1723 }
1724
1725 /* We did light-weight exit earlier, do full tear down now */
1726 if (cpufreq_driver->offline && cpufreq_driver->exit)
1727 cpufreq_driver->exit(policy);
1728
1729 up_write(&policy->rwsem);
1730
1731 cpufreq_policy_free(policy);
1732}
1733
1734/**
1735 * cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
1736 * @policy: Policy managing CPUs.
1737 * @new_freq: New CPU frequency.
1738 *
1739 * Adjust to the current frequency first and clean up later by either calling
1740 * cpufreq_update_policy(), or scheduling handle_update().
1741 */
1742static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1743 unsigned int new_freq)
1744{
1745 struct cpufreq_freqs freqs;
1746
1747 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1748 policy->cur, new_freq);
1749
1750 freqs.old = policy->cur;
1751 freqs.new = new_freq;
1752
1753 cpufreq_freq_transition_begin(policy, &freqs);
1754 cpufreq_freq_transition_end(policy, &freqs, 0);
1755}
1756
1757static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1758{
1759 unsigned int new_freq;
1760
1761 new_freq = cpufreq_driver->get(policy->cpu);
1762 if (!new_freq)
1763 return 0;
1764
1765 /*
1766 * If fast frequency switching is used with the given policy, the check
1767 * against policy->cur is pointless, so skip it in that case.
1768 */
1769 if (policy->fast_switch_enabled || !has_target())
1770 return new_freq;
1771
1772 if (policy->cur != new_freq) {
1773 /*
1774 * For some platforms, the frequency returned by hardware may be
1775 * slightly different from what is provided in the frequency
1776 * table, for example hardware may return 499 MHz instead of 500
1777 * MHz. In such cases it is better to avoid getting into
1778 * unnecessary frequency updates.
1779 */
1780 if (abs(policy->cur - new_freq) < KHZ_PER_MHZ)
1781 return policy->cur;
1782
1783 cpufreq_out_of_sync(policy, new_freq);
1784 if (update)
1785 schedule_work(&policy->update);
1786 }
1787
1788 return new_freq;
1789}
1790
1791/**
1792 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1793 * @cpu: CPU number
1794 *
1795 * This is the last known freq, without actually getting it from the driver.
1796 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1797 */
1798unsigned int cpufreq_quick_get(unsigned int cpu)
1799{
1800 struct cpufreq_policy *policy;
1801 unsigned int ret_freq = 0;
1802 unsigned long flags;
1803
1804 read_lock_irqsave(&cpufreq_driver_lock, flags);
1805
1806 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1807 ret_freq = cpufreq_driver->get(cpu);
1808 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1809 return ret_freq;
1810 }
1811
1812 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1813
1814 policy = cpufreq_cpu_get(cpu);
1815 if (policy) {
1816 ret_freq = policy->cur;
1817 cpufreq_cpu_put(policy);
1818 }
1819
1820 return ret_freq;
1821}
1822EXPORT_SYMBOL(cpufreq_quick_get);
1823
1824/**
1825 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1826 * @cpu: CPU number
1827 *
1828 * Just return the max possible frequency for a given CPU.
1829 */
1830unsigned int cpufreq_quick_get_max(unsigned int cpu)
1831{
1832 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1833 unsigned int ret_freq = 0;
1834
1835 if (policy) {
1836 ret_freq = policy->max;
1837 cpufreq_cpu_put(policy);
1838 }
1839
1840 return ret_freq;
1841}
1842EXPORT_SYMBOL(cpufreq_quick_get_max);
1843
1844/**
1845 * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
1846 * @cpu: CPU number
1847 *
1848 * The default return value is the max_freq field of cpuinfo.
1849 */
1850__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
1851{
1852 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1853 unsigned int ret_freq = 0;
1854
1855 if (policy) {
1856 ret_freq = policy->cpuinfo.max_freq;
1857 cpufreq_cpu_put(policy);
1858 }
1859
1860 return ret_freq;
1861}
1862EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
1863
1864static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1865{
1866 if (unlikely(policy_is_inactive(policy)))
1867 return 0;
1868
1869 return cpufreq_verify_current_freq(policy, true);
1870}
1871
1872/**
1873 * cpufreq_get - get the current CPU frequency (in kHz)
1874 * @cpu: CPU number
1875 *
1876 * Get the CPU current (static) CPU frequency
1877 */
1878unsigned int cpufreq_get(unsigned int cpu)
1879{
1880 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1881 unsigned int ret_freq = 0;
1882
1883 if (policy) {
1884 down_read(&policy->rwsem);
1885 if (cpufreq_driver->get)
1886 ret_freq = __cpufreq_get(policy);
1887 up_read(&policy->rwsem);
1888
1889 cpufreq_cpu_put(policy);
1890 }
1891
1892 return ret_freq;
1893}
1894EXPORT_SYMBOL(cpufreq_get);
1895
1896static struct subsys_interface cpufreq_interface = {
1897 .name = "cpufreq",
1898 .subsys = &cpu_subsys,
1899 .add_dev = cpufreq_add_dev,
1900 .remove_dev = cpufreq_remove_dev,
1901};
1902
1903/*
1904 * In case platform wants some specific frequency to be configured
1905 * during suspend..
1906 */
1907int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1908{
1909 int ret;
1910
1911 if (!policy->suspend_freq) {
1912 pr_debug("%s: suspend_freq not defined\n", __func__);
1913 return 0;
1914 }
1915
1916 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1917 policy->suspend_freq);
1918
1919 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1920 CPUFREQ_RELATION_H);
1921 if (ret)
1922 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1923 __func__, policy->suspend_freq, ret);
1924
1925 return ret;
1926}
1927EXPORT_SYMBOL(cpufreq_generic_suspend);
1928
1929/**
1930 * cpufreq_suspend() - Suspend CPUFreq governors.
1931 *
1932 * Called during system wide Suspend/Hibernate cycles for suspending governors
1933 * as some platforms can't change frequency after this point in suspend cycle.
1934 * Because some of the devices (like: i2c, regulators, etc) they use for
1935 * changing frequency are suspended quickly after this point.
1936 */
1937void cpufreq_suspend(void)
1938{
1939 struct cpufreq_policy *policy;
1940
1941 if (!cpufreq_driver)
1942 return;
1943
1944 if (!has_target() && !cpufreq_driver->suspend)
1945 goto suspend;
1946
1947 pr_debug("%s: Suspending Governors\n", __func__);
1948
1949 for_each_active_policy(policy) {
1950 if (has_target()) {
1951 down_write(&policy->rwsem);
1952 cpufreq_stop_governor(policy);
1953 up_write(&policy->rwsem);
1954 }
1955
1956 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1957 pr_err("%s: Failed to suspend driver: %s\n", __func__,
1958 cpufreq_driver->name);
1959 }
1960
1961suspend:
1962 cpufreq_suspended = true;
1963}
1964
1965/**
1966 * cpufreq_resume() - Resume CPUFreq governors.
1967 *
1968 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1969 * are suspended with cpufreq_suspend().
1970 */
1971void cpufreq_resume(void)
1972{
1973 struct cpufreq_policy *policy;
1974 int ret;
1975
1976 if (!cpufreq_driver)
1977 return;
1978
1979 if (unlikely(!cpufreq_suspended))
1980 return;
1981
1982 cpufreq_suspended = false;
1983
1984 if (!has_target() && !cpufreq_driver->resume)
1985 return;
1986
1987 pr_debug("%s: Resuming Governors\n", __func__);
1988
1989 for_each_active_policy(policy) {
1990 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1991 pr_err("%s: Failed to resume driver: %s\n", __func__,
1992 cpufreq_driver->name);
1993 } else if (has_target()) {
1994 down_write(&policy->rwsem);
1995 ret = cpufreq_start_governor(policy);
1996 up_write(&policy->rwsem);
1997
1998 if (ret)
1999 pr_err("%s: Failed to start governor for CPU%u's policy\n",
2000 __func__, policy->cpu);
2001 }
2002 }
2003}
2004
2005/**
2006 * cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
2007 * @flags: Flags to test against the current cpufreq driver's flags.
2008 *
2009 * Assumes that the driver is there, so callers must ensure that this is the
2010 * case.
2011 */
2012bool cpufreq_driver_test_flags(u16 flags)
2013{
2014 return !!(cpufreq_driver->flags & flags);
2015}
2016
2017/**
2018 * cpufreq_get_current_driver - Return the current driver's name.
2019 *
2020 * Return the name string of the currently registered cpufreq driver or NULL if
2021 * none.
2022 */
2023const char *cpufreq_get_current_driver(void)
2024{
2025 if (cpufreq_driver)
2026 return cpufreq_driver->name;
2027
2028 return NULL;
2029}
2030EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
2031
2032/**
2033 * cpufreq_get_driver_data - Return current driver data.
2034 *
2035 * Return the private data of the currently registered cpufreq driver, or NULL
2036 * if no cpufreq driver has been registered.
2037 */
2038void *cpufreq_get_driver_data(void)
2039{
2040 if (cpufreq_driver)
2041 return cpufreq_driver->driver_data;
2042
2043 return NULL;
2044}
2045EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
2046
2047/*********************************************************************
2048 * NOTIFIER LISTS INTERFACE *
2049 *********************************************************************/
2050
2051/**
2052 * cpufreq_register_notifier - Register a notifier with cpufreq.
2053 * @nb: notifier function to register.
2054 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2055 *
2056 * Add a notifier to one of two lists: either a list of notifiers that run on
2057 * clock rate changes (once before and once after every transition), or a list
2058 * of notifiers that ron on cpufreq policy changes.
2059 *
2060 * This function may sleep and it has the same return values as
2061 * blocking_notifier_chain_register().
2062 */
2063int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
2064{
2065 int ret;
2066
2067 if (cpufreq_disabled())
2068 return -EINVAL;
2069
2070 switch (list) {
2071 case CPUFREQ_TRANSITION_NOTIFIER:
2072 mutex_lock(&cpufreq_fast_switch_lock);
2073
2074 if (cpufreq_fast_switch_count > 0) {
2075 mutex_unlock(&cpufreq_fast_switch_lock);
2076 return -EBUSY;
2077 }
2078 ret = srcu_notifier_chain_register(
2079 &cpufreq_transition_notifier_list, nb);
2080 if (!ret)
2081 cpufreq_fast_switch_count--;
2082
2083 mutex_unlock(&cpufreq_fast_switch_lock);
2084 break;
2085 case CPUFREQ_POLICY_NOTIFIER:
2086 ret = blocking_notifier_chain_register(
2087 &cpufreq_policy_notifier_list, nb);
2088 break;
2089 default:
2090 ret = -EINVAL;
2091 }
2092
2093 return ret;
2094}
2095EXPORT_SYMBOL(cpufreq_register_notifier);
2096
2097/**
2098 * cpufreq_unregister_notifier - Unregister a notifier from cpufreq.
2099 * @nb: notifier block to be unregistered.
2100 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2101 *
2102 * Remove a notifier from one of the cpufreq notifier lists.
2103 *
2104 * This function may sleep and it has the same return values as
2105 * blocking_notifier_chain_unregister().
2106 */
2107int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
2108{
2109 int ret;
2110
2111 if (cpufreq_disabled())
2112 return -EINVAL;
2113
2114 switch (list) {
2115 case CPUFREQ_TRANSITION_NOTIFIER:
2116 mutex_lock(&cpufreq_fast_switch_lock);
2117
2118 ret = srcu_notifier_chain_unregister(
2119 &cpufreq_transition_notifier_list, nb);
2120 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
2121 cpufreq_fast_switch_count++;
2122
2123 mutex_unlock(&cpufreq_fast_switch_lock);
2124 break;
2125 case CPUFREQ_POLICY_NOTIFIER:
2126 ret = blocking_notifier_chain_unregister(
2127 &cpufreq_policy_notifier_list, nb);
2128 break;
2129 default:
2130 ret = -EINVAL;
2131 }
2132
2133 return ret;
2134}
2135EXPORT_SYMBOL(cpufreq_unregister_notifier);
2136
2137
2138/*********************************************************************
2139 * GOVERNORS *
2140 *********************************************************************/
2141
2142/**
2143 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
2144 * @policy: cpufreq policy to switch the frequency for.
2145 * @target_freq: New frequency to set (may be approximate).
2146 *
2147 * Carry out a fast frequency switch without sleeping.
2148 *
2149 * The driver's ->fast_switch() callback invoked by this function must be
2150 * suitable for being called from within RCU-sched read-side critical sections
2151 * and it is expected to select the minimum available frequency greater than or
2152 * equal to @target_freq (CPUFREQ_RELATION_L).
2153 *
2154 * This function must not be called if policy->fast_switch_enabled is unset.
2155 *
2156 * Governors calling this function must guarantee that it will never be invoked
2157 * twice in parallel for the same policy and that it will never be called in
2158 * parallel with either ->target() or ->target_index() for the same policy.
2159 *
2160 * Returns the actual frequency set for the CPU.
2161 *
2162 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2163 * error condition, the hardware configuration must be preserved.
2164 */
2165unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2166 unsigned int target_freq)
2167{
2168 unsigned int freq;
2169 int cpu;
2170
2171 target_freq = clamp_val(target_freq, policy->min, policy->max);
2172 freq = cpufreq_driver->fast_switch(policy, target_freq);
2173
2174 if (!freq)
2175 return 0;
2176
2177 policy->cur = freq;
2178 arch_set_freq_scale(policy->related_cpus, freq,
2179 arch_scale_freq_ref(policy->cpu));
2180 cpufreq_stats_record_transition(policy, freq);
2181
2182 if (trace_cpu_frequency_enabled()) {
2183 for_each_cpu(cpu, policy->cpus)
2184 trace_cpu_frequency(freq, cpu);
2185 }
2186
2187 return freq;
2188}
2189EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2190
2191/**
2192 * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
2193 * @cpu: Target CPU.
2194 * @min_perf: Minimum (required) performance level (units of @capacity).
2195 * @target_perf: Target (desired) performance level (units of @capacity).
2196 * @capacity: Capacity of the target CPU.
2197 *
2198 * Carry out a fast performance level switch of @cpu without sleeping.
2199 *
2200 * The driver's ->adjust_perf() callback invoked by this function must be
2201 * suitable for being called from within RCU-sched read-side critical sections
2202 * and it is expected to select a suitable performance level equal to or above
2203 * @min_perf and preferably equal to or below @target_perf.
2204 *
2205 * This function must not be called if policy->fast_switch_enabled is unset.
2206 *
2207 * Governors calling this function must guarantee that it will never be invoked
2208 * twice in parallel for the same CPU and that it will never be called in
2209 * parallel with either ->target() or ->target_index() or ->fast_switch() for
2210 * the same CPU.
2211 */
2212void cpufreq_driver_adjust_perf(unsigned int cpu,
2213 unsigned long min_perf,
2214 unsigned long target_perf,
2215 unsigned long capacity)
2216{
2217 cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
2218}
2219
2220/**
2221 * cpufreq_driver_has_adjust_perf - Check "direct fast switch" callback.
2222 *
2223 * Return 'true' if the ->adjust_perf callback is present for the
2224 * current driver or 'false' otherwise.
2225 */
2226bool cpufreq_driver_has_adjust_perf(void)
2227{
2228 return !!cpufreq_driver->adjust_perf;
2229}
2230
2231/* Must set freqs->new to intermediate frequency */
2232static int __target_intermediate(struct cpufreq_policy *policy,
2233 struct cpufreq_freqs *freqs, int index)
2234{
2235 int ret;
2236
2237 freqs->new = cpufreq_driver->get_intermediate(policy, index);
2238
2239 /* We don't need to switch to intermediate freq */
2240 if (!freqs->new)
2241 return 0;
2242
2243 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2244 __func__, policy->cpu, freqs->old, freqs->new);
2245
2246 cpufreq_freq_transition_begin(policy, freqs);
2247 ret = cpufreq_driver->target_intermediate(policy, index);
2248 cpufreq_freq_transition_end(policy, freqs, ret);
2249
2250 if (ret)
2251 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2252 __func__, ret);
2253
2254 return ret;
2255}
2256
2257static int __target_index(struct cpufreq_policy *policy, int index)
2258{
2259 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2260 unsigned int restore_freq, intermediate_freq = 0;
2261 unsigned int newfreq = policy->freq_table[index].frequency;
2262 int retval = -EINVAL;
2263 bool notify;
2264
2265 if (newfreq == policy->cur)
2266 return 0;
2267
2268 /* Save last value to restore later on errors */
2269 restore_freq = policy->cur;
2270
2271 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2272 if (notify) {
2273 /* Handle switching to intermediate frequency */
2274 if (cpufreq_driver->get_intermediate) {
2275 retval = __target_intermediate(policy, &freqs, index);
2276 if (retval)
2277 return retval;
2278
2279 intermediate_freq = freqs.new;
2280 /* Set old freq to intermediate */
2281 if (intermediate_freq)
2282 freqs.old = freqs.new;
2283 }
2284
2285 freqs.new = newfreq;
2286 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2287 __func__, policy->cpu, freqs.old, freqs.new);
2288
2289 cpufreq_freq_transition_begin(policy, &freqs);
2290 }
2291
2292 retval = cpufreq_driver->target_index(policy, index);
2293 if (retval)
2294 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2295 retval);
2296
2297 if (notify) {
2298 cpufreq_freq_transition_end(policy, &freqs, retval);
2299
2300 /*
2301 * Failed after setting to intermediate freq? Driver should have
2302 * reverted back to initial frequency and so should we. Check
2303 * here for intermediate_freq instead of get_intermediate, in
2304 * case we haven't switched to intermediate freq at all.
2305 */
2306 if (unlikely(retval && intermediate_freq)) {
2307 freqs.old = intermediate_freq;
2308 freqs.new = restore_freq;
2309 cpufreq_freq_transition_begin(policy, &freqs);
2310 cpufreq_freq_transition_end(policy, &freqs, 0);
2311 }
2312 }
2313
2314 return retval;
2315}
2316
2317int __cpufreq_driver_target(struct cpufreq_policy *policy,
2318 unsigned int target_freq,
2319 unsigned int relation)
2320{
2321 unsigned int old_target_freq = target_freq;
2322
2323 if (cpufreq_disabled())
2324 return -ENODEV;
2325
2326 target_freq = __resolve_freq(policy, target_freq, relation);
2327
2328 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2329 policy->cpu, target_freq, relation, old_target_freq);
2330
2331 /*
2332 * This might look like a redundant call as we are checking it again
2333 * after finding index. But it is left intentionally for cases where
2334 * exactly same freq is called again and so we can save on few function
2335 * calls.
2336 */
2337 if (target_freq == policy->cur &&
2338 !(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS))
2339 return 0;
2340
2341 if (cpufreq_driver->target) {
2342 /*
2343 * If the driver hasn't setup a single inefficient frequency,
2344 * it's unlikely it knows how to decode CPUFREQ_RELATION_E.
2345 */
2346 if (!policy->efficiencies_available)
2347 relation &= ~CPUFREQ_RELATION_E;
2348
2349 return cpufreq_driver->target(policy, target_freq, relation);
2350 }
2351
2352 if (!cpufreq_driver->target_index)
2353 return -EINVAL;
2354
2355 return __target_index(policy, policy->cached_resolved_idx);
2356}
2357EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2358
2359int cpufreq_driver_target(struct cpufreq_policy *policy,
2360 unsigned int target_freq,
2361 unsigned int relation)
2362{
2363 int ret;
2364
2365 down_write(&policy->rwsem);
2366
2367 ret = __cpufreq_driver_target(policy, target_freq, relation);
2368
2369 up_write(&policy->rwsem);
2370
2371 return ret;
2372}
2373EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2374
2375__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2376{
2377 return NULL;
2378}
2379
2380static int cpufreq_init_governor(struct cpufreq_policy *policy)
2381{
2382 int ret;
2383
2384 /* Don't start any governor operations if we are entering suspend */
2385 if (cpufreq_suspended)
2386 return 0;
2387 /*
2388 * Governor might not be initiated here if ACPI _PPC changed
2389 * notification happened, so check it.
2390 */
2391 if (!policy->governor)
2392 return -EINVAL;
2393
2394 /* Platform doesn't want dynamic frequency switching ? */
2395 if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING &&
2396 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2397 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2398
2399 if (gov) {
2400 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2401 policy->governor->name, gov->name);
2402 policy->governor = gov;
2403 } else {
2404 return -EINVAL;
2405 }
2406 }
2407
2408 if (!try_module_get(policy->governor->owner))
2409 return -EINVAL;
2410
2411 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2412
2413 if (policy->governor->init) {
2414 ret = policy->governor->init(policy);
2415 if (ret) {
2416 module_put(policy->governor->owner);
2417 return ret;
2418 }
2419 }
2420
2421 policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET);
2422
2423 return 0;
2424}
2425
2426static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2427{
2428 if (cpufreq_suspended || !policy->governor)
2429 return;
2430
2431 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2432
2433 if (policy->governor->exit)
2434 policy->governor->exit(policy);
2435
2436 module_put(policy->governor->owner);
2437}
2438
2439int cpufreq_start_governor(struct cpufreq_policy *policy)
2440{
2441 int ret;
2442
2443 if (cpufreq_suspended)
2444 return 0;
2445
2446 if (!policy->governor)
2447 return -EINVAL;
2448
2449 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2450
2451 if (cpufreq_driver->get)
2452 cpufreq_verify_current_freq(policy, false);
2453
2454 if (policy->governor->start) {
2455 ret = policy->governor->start(policy);
2456 if (ret)
2457 return ret;
2458 }
2459
2460 if (policy->governor->limits)
2461 policy->governor->limits(policy);
2462
2463 return 0;
2464}
2465
2466void cpufreq_stop_governor(struct cpufreq_policy *policy)
2467{
2468 if (cpufreq_suspended || !policy->governor)
2469 return;
2470
2471 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2472
2473 if (policy->governor->stop)
2474 policy->governor->stop(policy);
2475}
2476
2477static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2478{
2479 if (cpufreq_suspended || !policy->governor)
2480 return;
2481
2482 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2483
2484 if (policy->governor->limits)
2485 policy->governor->limits(policy);
2486}
2487
2488int cpufreq_register_governor(struct cpufreq_governor *governor)
2489{
2490 int err;
2491
2492 if (!governor)
2493 return -EINVAL;
2494
2495 if (cpufreq_disabled())
2496 return -ENODEV;
2497
2498 mutex_lock(&cpufreq_governor_mutex);
2499
2500 err = -EBUSY;
2501 if (!find_governor(governor->name)) {
2502 err = 0;
2503 list_add(&governor->governor_list, &cpufreq_governor_list);
2504 }
2505
2506 mutex_unlock(&cpufreq_governor_mutex);
2507 return err;
2508}
2509EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2510
2511void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2512{
2513 struct cpufreq_policy *policy;
2514 unsigned long flags;
2515
2516 if (!governor)
2517 return;
2518
2519 if (cpufreq_disabled())
2520 return;
2521
2522 /* clear last_governor for all inactive policies */
2523 read_lock_irqsave(&cpufreq_driver_lock, flags);
2524 for_each_inactive_policy(policy) {
2525 if (!strcmp(policy->last_governor, governor->name)) {
2526 policy->governor = NULL;
2527 strcpy(policy->last_governor, "\0");
2528 }
2529 }
2530 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2531
2532 mutex_lock(&cpufreq_governor_mutex);
2533 list_del(&governor->governor_list);
2534 mutex_unlock(&cpufreq_governor_mutex);
2535}
2536EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2537
2538
2539/*********************************************************************
2540 * POLICY INTERFACE *
2541 *********************************************************************/
2542
2543/**
2544 * cpufreq_get_policy - get the current cpufreq_policy
2545 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2546 * is written
2547 * @cpu: CPU to find the policy for
2548 *
2549 * Reads the current cpufreq policy.
2550 */
2551int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2552{
2553 struct cpufreq_policy *cpu_policy;
2554 if (!policy)
2555 return -EINVAL;
2556
2557 cpu_policy = cpufreq_cpu_get(cpu);
2558 if (!cpu_policy)
2559 return -EINVAL;
2560
2561 memcpy(policy, cpu_policy, sizeof(*policy));
2562
2563 cpufreq_cpu_put(cpu_policy);
2564 return 0;
2565}
2566EXPORT_SYMBOL(cpufreq_get_policy);
2567
2568DEFINE_PER_CPU(unsigned long, cpufreq_pressure);
2569
2570/**
2571 * cpufreq_update_pressure() - Update cpufreq pressure for CPUs
2572 * @policy: cpufreq policy of the CPUs.
2573 *
2574 * Update the value of cpufreq pressure for all @cpus in the policy.
2575 */
2576static void cpufreq_update_pressure(struct cpufreq_policy *policy)
2577{
2578 unsigned long max_capacity, capped_freq, pressure;
2579 u32 max_freq;
2580 int cpu;
2581
2582 cpu = cpumask_first(policy->related_cpus);
2583 max_freq = arch_scale_freq_ref(cpu);
2584 capped_freq = policy->max;
2585
2586 /*
2587 * Handle properly the boost frequencies, which should simply clean
2588 * the cpufreq pressure value.
2589 */
2590 if (max_freq <= capped_freq) {
2591 pressure = 0;
2592 } else {
2593 max_capacity = arch_scale_cpu_capacity(cpu);
2594 pressure = max_capacity -
2595 mult_frac(max_capacity, capped_freq, max_freq);
2596 }
2597
2598 for_each_cpu(cpu, policy->related_cpus)
2599 WRITE_ONCE(per_cpu(cpufreq_pressure, cpu), pressure);
2600}
2601
2602/**
2603 * cpufreq_set_policy - Modify cpufreq policy parameters.
2604 * @policy: Policy object to modify.
2605 * @new_gov: Policy governor pointer.
2606 * @new_pol: Policy value (for drivers with built-in governors).
2607 *
2608 * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
2609 * limits to be set for the policy, update @policy with the verified limits
2610 * values and either invoke the driver's ->setpolicy() callback (if present) or
2611 * carry out a governor update for @policy. That is, run the current governor's
2612 * ->limits() callback (if @new_gov points to the same object as the one in
2613 * @policy) or replace the governor for @policy with @new_gov.
2614 *
2615 * The cpuinfo part of @policy is not updated by this function.
2616 */
2617static int cpufreq_set_policy(struct cpufreq_policy *policy,
2618 struct cpufreq_governor *new_gov,
2619 unsigned int new_pol)
2620{
2621 struct cpufreq_policy_data new_data;
2622 struct cpufreq_governor *old_gov;
2623 int ret;
2624
2625 memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2626 new_data.freq_table = policy->freq_table;
2627 new_data.cpu = policy->cpu;
2628 /*
2629 * PM QoS framework collects all the requests from users and provide us
2630 * the final aggregated value here.
2631 */
2632 new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2633 new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2634
2635 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2636 new_data.cpu, new_data.min, new_data.max);
2637
2638 /*
2639 * Verify that the CPU speed can be set within these limits and make sure
2640 * that min <= max.
2641 */
2642 ret = cpufreq_driver->verify(&new_data);
2643 if (ret)
2644 return ret;
2645
2646 /*
2647 * Resolve policy min/max to available frequencies. It ensures
2648 * no frequency resolution will neither overshoot the requested maximum
2649 * nor undershoot the requested minimum.
2650 */
2651 policy->min = new_data.min;
2652 policy->max = new_data.max;
2653 policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
2654 policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
2655 trace_cpu_frequency_limits(policy);
2656
2657 cpufreq_update_pressure(policy);
2658
2659 policy->cached_target_freq = UINT_MAX;
2660
2661 pr_debug("new min and max freqs are %u - %u kHz\n",
2662 policy->min, policy->max);
2663
2664 if (cpufreq_driver->setpolicy) {
2665 policy->policy = new_pol;
2666 pr_debug("setting range\n");
2667 return cpufreq_driver->setpolicy(policy);
2668 }
2669
2670 if (new_gov == policy->governor) {
2671 pr_debug("governor limits update\n");
2672 cpufreq_governor_limits(policy);
2673 return 0;
2674 }
2675
2676 pr_debug("governor switch\n");
2677
2678 /* save old, working values */
2679 old_gov = policy->governor;
2680 /* end old governor */
2681 if (old_gov) {
2682 cpufreq_stop_governor(policy);
2683 cpufreq_exit_governor(policy);
2684 }
2685
2686 /* start new governor */
2687 policy->governor = new_gov;
2688 ret = cpufreq_init_governor(policy);
2689 if (!ret) {
2690 ret = cpufreq_start_governor(policy);
2691 if (!ret) {
2692 pr_debug("governor change\n");
2693 return 0;
2694 }
2695 cpufreq_exit_governor(policy);
2696 }
2697
2698 /* new governor failed, so re-start old one */
2699 pr_debug("starting governor %s failed\n", policy->governor->name);
2700 if (old_gov) {
2701 policy->governor = old_gov;
2702 if (cpufreq_init_governor(policy))
2703 policy->governor = NULL;
2704 else
2705 cpufreq_start_governor(policy);
2706 }
2707
2708 return ret;
2709}
2710
2711/**
2712 * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2713 * @cpu: CPU to re-evaluate the policy for.
2714 *
2715 * Update the current frequency for the cpufreq policy of @cpu and use
2716 * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2717 * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2718 * for the policy in question, among other things.
2719 */
2720void cpufreq_update_policy(unsigned int cpu)
2721{
2722 struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2723
2724 if (!policy)
2725 return;
2726
2727 /*
2728 * BIOS might change freq behind our back
2729 * -> ask driver for current freq and notify governors about a change
2730 */
2731 if (cpufreq_driver->get && has_target() &&
2732 (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2733 goto unlock;
2734
2735 refresh_frequency_limits(policy);
2736
2737unlock:
2738 cpufreq_cpu_release(policy);
2739}
2740EXPORT_SYMBOL(cpufreq_update_policy);
2741
2742/**
2743 * cpufreq_update_limits - Update policy limits for a given CPU.
2744 * @cpu: CPU to update the policy limits for.
2745 *
2746 * Invoke the driver's ->update_limits callback if present or call
2747 * cpufreq_update_policy() for @cpu.
2748 */
2749void cpufreq_update_limits(unsigned int cpu)
2750{
2751 if (cpufreq_driver->update_limits)
2752 cpufreq_driver->update_limits(cpu);
2753 else
2754 cpufreq_update_policy(cpu);
2755}
2756EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2757
2758/*********************************************************************
2759 * BOOST *
2760 *********************************************************************/
2761static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
2762{
2763 int ret;
2764
2765 if (!policy->freq_table)
2766 return -ENXIO;
2767
2768 ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
2769 if (ret) {
2770 pr_err("%s: Policy frequency update failed\n", __func__);
2771 return ret;
2772 }
2773
2774 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2775 if (ret < 0)
2776 return ret;
2777
2778 return 0;
2779}
2780
2781int cpufreq_boost_trigger_state(int state)
2782{
2783 struct cpufreq_policy *policy;
2784 unsigned long flags;
2785 int ret = 0;
2786
2787 if (cpufreq_driver->boost_enabled == state)
2788 return 0;
2789
2790 write_lock_irqsave(&cpufreq_driver_lock, flags);
2791 cpufreq_driver->boost_enabled = state;
2792 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2793
2794 cpus_read_lock();
2795 for_each_active_policy(policy) {
2796 policy->boost_enabled = state;
2797 ret = cpufreq_driver->set_boost(policy, state);
2798 if (ret) {
2799 policy->boost_enabled = !policy->boost_enabled;
2800 goto err_reset_state;
2801 }
2802 }
2803 cpus_read_unlock();
2804
2805 return 0;
2806
2807err_reset_state:
2808 cpus_read_unlock();
2809
2810 write_lock_irqsave(&cpufreq_driver_lock, flags);
2811 cpufreq_driver->boost_enabled = !state;
2812 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2813
2814 pr_err("%s: Cannot %s BOOST\n",
2815 __func__, state ? "enable" : "disable");
2816
2817 return ret;
2818}
2819
2820static bool cpufreq_boost_supported(void)
2821{
2822 return cpufreq_driver->set_boost;
2823}
2824
2825static int create_boost_sysfs_file(void)
2826{
2827 int ret;
2828
2829 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2830 if (ret)
2831 pr_err("%s: cannot register global BOOST sysfs file\n",
2832 __func__);
2833
2834 return ret;
2835}
2836
2837static void remove_boost_sysfs_file(void)
2838{
2839 if (cpufreq_boost_supported())
2840 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2841}
2842
2843int cpufreq_enable_boost_support(void)
2844{
2845 if (!cpufreq_driver)
2846 return -EINVAL;
2847
2848 if (cpufreq_boost_supported())
2849 return 0;
2850
2851 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2852
2853 /* This will get removed on driver unregister */
2854 return create_boost_sysfs_file();
2855}
2856EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2857
2858bool cpufreq_boost_enabled(void)
2859{
2860 return cpufreq_driver->boost_enabled;
2861}
2862EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2863
2864/*********************************************************************
2865 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2866 *********************************************************************/
2867static enum cpuhp_state hp_online;
2868
2869static int cpuhp_cpufreq_online(unsigned int cpu)
2870{
2871 cpufreq_online(cpu);
2872
2873 return 0;
2874}
2875
2876static int cpuhp_cpufreq_offline(unsigned int cpu)
2877{
2878 cpufreq_offline(cpu);
2879
2880 return 0;
2881}
2882
2883/**
2884 * cpufreq_register_driver - register a CPU Frequency driver
2885 * @driver_data: A struct cpufreq_driver containing the values#
2886 * submitted by the CPU Frequency driver.
2887 *
2888 * Registers a CPU Frequency driver to this core code. This code
2889 * returns zero on success, -EEXIST when another driver got here first
2890 * (and isn't unregistered in the meantime).
2891 *
2892 */
2893int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2894{
2895 unsigned long flags;
2896 int ret;
2897
2898 if (cpufreq_disabled())
2899 return -ENODEV;
2900
2901 /*
2902 * The cpufreq core depends heavily on the availability of device
2903 * structure, make sure they are available before proceeding further.
2904 */
2905 if (!get_cpu_device(0))
2906 return -EPROBE_DEFER;
2907
2908 if (!driver_data || !driver_data->verify || !driver_data->init ||
2909 !(driver_data->setpolicy || driver_data->target_index ||
2910 driver_data->target) ||
2911 (driver_data->setpolicy && (driver_data->target_index ||
2912 driver_data->target)) ||
2913 (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2914 (!driver_data->online != !driver_data->offline) ||
2915 (driver_data->adjust_perf && !driver_data->fast_switch))
2916 return -EINVAL;
2917
2918 pr_debug("trying to register driver %s\n", driver_data->name);
2919
2920 /* Protect against concurrent CPU online/offline. */
2921 cpus_read_lock();
2922
2923 write_lock_irqsave(&cpufreq_driver_lock, flags);
2924 if (cpufreq_driver) {
2925 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2926 ret = -EEXIST;
2927 goto out;
2928 }
2929 cpufreq_driver = driver_data;
2930 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2931
2932 /*
2933 * Mark support for the scheduler's frequency invariance engine for
2934 * drivers that implement target(), target_index() or fast_switch().
2935 */
2936 if (!cpufreq_driver->setpolicy) {
2937 static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
2938 pr_debug("supports frequency invariance");
2939 }
2940
2941 if (driver_data->setpolicy)
2942 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2943
2944 if (cpufreq_boost_supported()) {
2945 ret = create_boost_sysfs_file();
2946 if (ret)
2947 goto err_null_driver;
2948 }
2949
2950 ret = subsys_interface_register(&cpufreq_interface);
2951 if (ret)
2952 goto err_boost_unreg;
2953
2954 if (unlikely(list_empty(&cpufreq_policy_list))) {
2955 /* if all ->init() calls failed, unregister */
2956 ret = -ENODEV;
2957 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2958 driver_data->name);
2959 goto err_if_unreg;
2960 }
2961
2962 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2963 "cpufreq:online",
2964 cpuhp_cpufreq_online,
2965 cpuhp_cpufreq_offline);
2966 if (ret < 0)
2967 goto err_if_unreg;
2968 hp_online = ret;
2969 ret = 0;
2970
2971 pr_debug("driver %s up and running\n", driver_data->name);
2972 goto out;
2973
2974err_if_unreg:
2975 subsys_interface_unregister(&cpufreq_interface);
2976err_boost_unreg:
2977 remove_boost_sysfs_file();
2978err_null_driver:
2979 write_lock_irqsave(&cpufreq_driver_lock, flags);
2980 cpufreq_driver = NULL;
2981 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2982out:
2983 cpus_read_unlock();
2984 return ret;
2985}
2986EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2987
2988/*
2989 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2990 *
2991 * Unregister the current CPUFreq driver. Only call this if you have
2992 * the right to do so, i.e. if you have succeeded in initialising before!
2993 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2994 * currently not initialised.
2995 */
2996void cpufreq_unregister_driver(struct cpufreq_driver *driver)
2997{
2998 unsigned long flags;
2999
3000 if (WARN_ON(!cpufreq_driver || (driver != cpufreq_driver)))
3001 return;
3002
3003 pr_debug("unregistering driver %s\n", driver->name);
3004
3005 /* Protect against concurrent cpu hotplug */
3006 cpus_read_lock();
3007 subsys_interface_unregister(&cpufreq_interface);
3008 remove_boost_sysfs_file();
3009 static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
3010 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
3011
3012 write_lock_irqsave(&cpufreq_driver_lock, flags);
3013
3014 cpufreq_driver = NULL;
3015
3016 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
3017 cpus_read_unlock();
3018}
3019EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
3020
3021static int __init cpufreq_core_init(void)
3022{
3023 struct cpufreq_governor *gov = cpufreq_default_governor();
3024 struct device *dev_root;
3025
3026 if (cpufreq_disabled())
3027 return -ENODEV;
3028
3029 dev_root = bus_get_dev_root(&cpu_subsys);
3030 if (dev_root) {
3031 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &dev_root->kobj);
3032 put_device(dev_root);
3033 }
3034 BUG_ON(!cpufreq_global_kobject);
3035
3036 if (!strlen(default_governor))
3037 strscpy(default_governor, gov->name, CPUFREQ_NAME_LEN);
3038
3039 return 0;
3040}
3041module_param(off, int, 0444);
3042module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
3043core_initcall(cpufreq_core_init);