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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 /*
580 * For platforms that can change the frequency very fast (< 10
581 * us), the above formula gives a decent transition delay. But
582 * for platforms where transition_latency is in milliseconds, it
583 * ends up giving unrealistic values.
584 *
585 * Cap the default transition delay to 10 ms, which seems to be
586 * a reasonable amount of time after which we should reevaluate
587 * the frequency.
588 */
589 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
590 }
591
592 return LATENCY_MULTIPLIER;
593}
594EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
595
596/*********************************************************************
597 * SYSFS INTERFACE *
598 *********************************************************************/
599static ssize_t show_boost(struct kobject *kobj,
600 struct kobj_attribute *attr, char *buf)
601{
602 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
603}
604
605static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
606 const char *buf, size_t count)
607{
608 int ret, enable;
609
610 ret = sscanf(buf, "%d", &enable);
611 if (ret != 1 || enable < 0 || enable > 1)
612 return -EINVAL;
613
614 if (cpufreq_boost_trigger_state(enable)) {
615 pr_err("%s: Cannot %s BOOST!\n",
616 __func__, enable ? "enable" : "disable");
617 return -EINVAL;
618 }
619
620 pr_debug("%s: cpufreq BOOST %s\n",
621 __func__, enable ? "enabled" : "disabled");
622
623 return count;
624}
625define_one_global_rw(boost);
626
627static ssize_t show_local_boost(struct cpufreq_policy *policy, char *buf)
628{
629 return sysfs_emit(buf, "%d\n", policy->boost_enabled);
630}
631
632static ssize_t store_local_boost(struct cpufreq_policy *policy,
633 const char *buf, size_t count)
634{
635 int ret, enable;
636
637 ret = kstrtoint(buf, 10, &enable);
638 if (ret || enable < 0 || enable > 1)
639 return -EINVAL;
640
641 if (!cpufreq_driver->boost_enabled)
642 return -EINVAL;
643
644 if (policy->boost_enabled == enable)
645 return count;
646
647 cpus_read_lock();
648 ret = cpufreq_driver->set_boost(policy, enable);
649 cpus_read_unlock();
650
651 if (ret)
652 return ret;
653
654 policy->boost_enabled = enable;
655
656 return count;
657}
658
659static struct freq_attr local_boost = __ATTR(boost, 0644, show_local_boost, store_local_boost);
660
661static struct cpufreq_governor *find_governor(const char *str_governor)
662{
663 struct cpufreq_governor *t;
664
665 for_each_governor(t)
666 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
667 return t;
668
669 return NULL;
670}
671
672static struct cpufreq_governor *get_governor(const char *str_governor)
673{
674 struct cpufreq_governor *t;
675
676 mutex_lock(&cpufreq_governor_mutex);
677 t = find_governor(str_governor);
678 if (!t)
679 goto unlock;
680
681 if (!try_module_get(t->owner))
682 t = NULL;
683
684unlock:
685 mutex_unlock(&cpufreq_governor_mutex);
686
687 return t;
688}
689
690static unsigned int cpufreq_parse_policy(char *str_governor)
691{
692 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN))
693 return CPUFREQ_POLICY_PERFORMANCE;
694
695 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN))
696 return CPUFREQ_POLICY_POWERSAVE;
697
698 return CPUFREQ_POLICY_UNKNOWN;
699}
700
701/**
702 * cpufreq_parse_governor - parse a governor string only for has_target()
703 * @str_governor: Governor name.
704 */
705static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
706{
707 struct cpufreq_governor *t;
708
709 t = get_governor(str_governor);
710 if (t)
711 return t;
712
713 if (request_module("cpufreq_%s", str_governor))
714 return NULL;
715
716 return get_governor(str_governor);
717}
718
719/*
720 * cpufreq_per_cpu_attr_read() / show_##file_name() -
721 * print out cpufreq information
722 *
723 * Write out information from cpufreq_driver->policy[cpu]; object must be
724 * "unsigned int".
725 */
726
727#define show_one(file_name, object) \
728static ssize_t show_##file_name \
729(struct cpufreq_policy *policy, char *buf) \
730{ \
731 return sprintf(buf, "%u\n", policy->object); \
732}
733
734show_one(cpuinfo_min_freq, cpuinfo.min_freq);
735show_one(cpuinfo_max_freq, cpuinfo.max_freq);
736show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
737show_one(scaling_min_freq, min);
738show_one(scaling_max_freq, max);
739
740__weak unsigned int arch_freq_get_on_cpu(int cpu)
741{
742 return 0;
743}
744
745static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
746{
747 ssize_t ret;
748 unsigned int freq;
749
750 freq = arch_freq_get_on_cpu(policy->cpu);
751 if (freq)
752 ret = sprintf(buf, "%u\n", freq);
753 else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
754 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
755 else
756 ret = sprintf(buf, "%u\n", policy->cur);
757 return ret;
758}
759
760/*
761 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
762 */
763#define store_one(file_name, object) \
764static ssize_t store_##file_name \
765(struct cpufreq_policy *policy, const char *buf, size_t count) \
766{ \
767 unsigned long val; \
768 int ret; \
769 \
770 ret = kstrtoul(buf, 0, &val); \
771 if (ret) \
772 return ret; \
773 \
774 ret = freq_qos_update_request(policy->object##_freq_req, val);\
775 return ret >= 0 ? count : ret; \
776}
777
778store_one(scaling_min_freq, min);
779store_one(scaling_max_freq, max);
780
781/*
782 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
783 */
784static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
785 char *buf)
786{
787 unsigned int cur_freq = __cpufreq_get(policy);
788
789 if (cur_freq)
790 return sprintf(buf, "%u\n", cur_freq);
791
792 return sprintf(buf, "<unknown>\n");
793}
794
795/*
796 * show_scaling_governor - show the current policy for the specified CPU
797 */
798static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
799{
800 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
801 return sprintf(buf, "powersave\n");
802 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
803 return sprintf(buf, "performance\n");
804 else if (policy->governor)
805 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
806 policy->governor->name);
807 return -EINVAL;
808}
809
810/*
811 * store_scaling_governor - store policy for the specified CPU
812 */
813static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
814 const char *buf, size_t count)
815{
816 char str_governor[16];
817 int ret;
818
819 ret = sscanf(buf, "%15s", str_governor);
820 if (ret != 1)
821 return -EINVAL;
822
823 if (cpufreq_driver->setpolicy) {
824 unsigned int new_pol;
825
826 new_pol = cpufreq_parse_policy(str_governor);
827 if (!new_pol)
828 return -EINVAL;
829
830 ret = cpufreq_set_policy(policy, NULL, new_pol);
831 } else {
832 struct cpufreq_governor *new_gov;
833
834 new_gov = cpufreq_parse_governor(str_governor);
835 if (!new_gov)
836 return -EINVAL;
837
838 ret = cpufreq_set_policy(policy, new_gov,
839 CPUFREQ_POLICY_UNKNOWN);
840
841 module_put(new_gov->owner);
842 }
843
844 return ret ? ret : count;
845}
846
847/*
848 * show_scaling_driver - show the cpufreq driver currently loaded
849 */
850static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
851{
852 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
853}
854
855/*
856 * show_scaling_available_governors - show the available CPUfreq governors
857 */
858static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
859 char *buf)
860{
861 ssize_t i = 0;
862 struct cpufreq_governor *t;
863
864 if (!has_target()) {
865 i += sprintf(buf, "performance powersave");
866 goto out;
867 }
868
869 mutex_lock(&cpufreq_governor_mutex);
870 for_each_governor(t) {
871 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
872 - (CPUFREQ_NAME_LEN + 2)))
873 break;
874 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
875 }
876 mutex_unlock(&cpufreq_governor_mutex);
877out:
878 i += sprintf(&buf[i], "\n");
879 return i;
880}
881
882ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
883{
884 ssize_t i = 0;
885 unsigned int cpu;
886
887 for_each_cpu(cpu, mask) {
888 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u ", cpu);
889 if (i >= (PAGE_SIZE - 5))
890 break;
891 }
892
893 /* Remove the extra space at the end */
894 i--;
895
896 i += sprintf(&buf[i], "\n");
897 return i;
898}
899EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
900
901/*
902 * show_related_cpus - show the CPUs affected by each transition even if
903 * hw coordination is in use
904 */
905static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
906{
907 return cpufreq_show_cpus(policy->related_cpus, buf);
908}
909
910/*
911 * show_affected_cpus - show the CPUs affected by each transition
912 */
913static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
914{
915 return cpufreq_show_cpus(policy->cpus, buf);
916}
917
918static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
919 const char *buf, size_t count)
920{
921 unsigned int freq = 0;
922 unsigned int ret;
923
924 if (!policy->governor || !policy->governor->store_setspeed)
925 return -EINVAL;
926
927 ret = sscanf(buf, "%u", &freq);
928 if (ret != 1)
929 return -EINVAL;
930
931 policy->governor->store_setspeed(policy, freq);
932
933 return count;
934}
935
936static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
937{
938 if (!policy->governor || !policy->governor->show_setspeed)
939 return sprintf(buf, "<unsupported>\n");
940
941 return policy->governor->show_setspeed(policy, buf);
942}
943
944/*
945 * show_bios_limit - show the current cpufreq HW/BIOS limitation
946 */
947static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
948{
949 unsigned int limit;
950 int ret;
951 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
952 if (!ret)
953 return sprintf(buf, "%u\n", limit);
954 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
955}
956
957cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
958cpufreq_freq_attr_ro(cpuinfo_min_freq);
959cpufreq_freq_attr_ro(cpuinfo_max_freq);
960cpufreq_freq_attr_ro(cpuinfo_transition_latency);
961cpufreq_freq_attr_ro(scaling_available_governors);
962cpufreq_freq_attr_ro(scaling_driver);
963cpufreq_freq_attr_ro(scaling_cur_freq);
964cpufreq_freq_attr_ro(bios_limit);
965cpufreq_freq_attr_ro(related_cpus);
966cpufreq_freq_attr_ro(affected_cpus);
967cpufreq_freq_attr_rw(scaling_min_freq);
968cpufreq_freq_attr_rw(scaling_max_freq);
969cpufreq_freq_attr_rw(scaling_governor);
970cpufreq_freq_attr_rw(scaling_setspeed);
971
972static struct attribute *cpufreq_attrs[] = {
973 &cpuinfo_min_freq.attr,
974 &cpuinfo_max_freq.attr,
975 &cpuinfo_transition_latency.attr,
976 &scaling_min_freq.attr,
977 &scaling_max_freq.attr,
978 &affected_cpus.attr,
979 &related_cpus.attr,
980 &scaling_governor.attr,
981 &scaling_driver.attr,
982 &scaling_available_governors.attr,
983 &scaling_setspeed.attr,
984 NULL
985};
986ATTRIBUTE_GROUPS(cpufreq);
987
988#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
989#define to_attr(a) container_of(a, struct freq_attr, attr)
990
991static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
992{
993 struct cpufreq_policy *policy = to_policy(kobj);
994 struct freq_attr *fattr = to_attr(attr);
995 ssize_t ret = -EBUSY;
996
997 if (!fattr->show)
998 return -EIO;
999
1000 down_read(&policy->rwsem);
1001 if (likely(!policy_is_inactive(policy)))
1002 ret = fattr->show(policy, buf);
1003 up_read(&policy->rwsem);
1004
1005 return ret;
1006}
1007
1008static ssize_t store(struct kobject *kobj, struct attribute *attr,
1009 const char *buf, size_t count)
1010{
1011 struct cpufreq_policy *policy = to_policy(kobj);
1012 struct freq_attr *fattr = to_attr(attr);
1013 ssize_t ret = -EBUSY;
1014
1015 if (!fattr->store)
1016 return -EIO;
1017
1018 down_write(&policy->rwsem);
1019 if (likely(!policy_is_inactive(policy)))
1020 ret = fattr->store(policy, buf, count);
1021 up_write(&policy->rwsem);
1022
1023 return ret;
1024}
1025
1026static void cpufreq_sysfs_release(struct kobject *kobj)
1027{
1028 struct cpufreq_policy *policy = to_policy(kobj);
1029 pr_debug("last reference is dropped\n");
1030 complete(&policy->kobj_unregister);
1031}
1032
1033static const struct sysfs_ops sysfs_ops = {
1034 .show = show,
1035 .store = store,
1036};
1037
1038static const struct kobj_type ktype_cpufreq = {
1039 .sysfs_ops = &sysfs_ops,
1040 .default_groups = cpufreq_groups,
1041 .release = cpufreq_sysfs_release,
1042};
1043
1044static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
1045 struct device *dev)
1046{
1047 if (unlikely(!dev))
1048 return;
1049
1050 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1051 return;
1052
1053 dev_dbg(dev, "%s: Adding symlink\n", __func__);
1054 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
1055 dev_err(dev, "cpufreq symlink creation failed\n");
1056}
1057
1058static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu,
1059 struct device *dev)
1060{
1061 dev_dbg(dev, "%s: Removing symlink\n", __func__);
1062 sysfs_remove_link(&dev->kobj, "cpufreq");
1063 cpumask_clear_cpu(cpu, policy->real_cpus);
1064}
1065
1066static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1067{
1068 struct freq_attr **drv_attr;
1069 int ret = 0;
1070
1071 /* set up files for this cpu device */
1072 drv_attr = cpufreq_driver->attr;
1073 while (drv_attr && *drv_attr) {
1074 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1075 if (ret)
1076 return ret;
1077 drv_attr++;
1078 }
1079 if (cpufreq_driver->get) {
1080 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1081 if (ret)
1082 return ret;
1083 }
1084
1085 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1086 if (ret)
1087 return ret;
1088
1089 if (cpufreq_driver->bios_limit) {
1090 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1091 if (ret)
1092 return ret;
1093 }
1094
1095 if (cpufreq_boost_supported()) {
1096 ret = sysfs_create_file(&policy->kobj, &local_boost.attr);
1097 if (ret)
1098 return ret;
1099 }
1100
1101 return 0;
1102}
1103
1104static int cpufreq_init_policy(struct cpufreq_policy *policy)
1105{
1106 struct cpufreq_governor *gov = NULL;
1107 unsigned int pol = CPUFREQ_POLICY_UNKNOWN;
1108 int ret;
1109
1110 if (has_target()) {
1111 /* Update policy governor to the one used before hotplug. */
1112 gov = get_governor(policy->last_governor);
1113 if (gov) {
1114 pr_debug("Restoring governor %s for cpu %d\n",
1115 gov->name, policy->cpu);
1116 } else {
1117 gov = get_governor(default_governor);
1118 }
1119
1120 if (!gov) {
1121 gov = cpufreq_default_governor();
1122 __module_get(gov->owner);
1123 }
1124
1125 } else {
1126
1127 /* Use the default policy if there is no last_policy. */
1128 if (policy->last_policy) {
1129 pol = policy->last_policy;
1130 } else {
1131 pol = cpufreq_parse_policy(default_governor);
1132 /*
1133 * In case the default governor is neither "performance"
1134 * nor "powersave", fall back to the initial policy
1135 * value set by the driver.
1136 */
1137 if (pol == CPUFREQ_POLICY_UNKNOWN)
1138 pol = policy->policy;
1139 }
1140 if (pol != CPUFREQ_POLICY_PERFORMANCE &&
1141 pol != CPUFREQ_POLICY_POWERSAVE)
1142 return -ENODATA;
1143 }
1144
1145 ret = cpufreq_set_policy(policy, gov, pol);
1146 if (gov)
1147 module_put(gov->owner);
1148
1149 return ret;
1150}
1151
1152static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1153{
1154 int ret = 0;
1155
1156 /* Has this CPU been taken care of already? */
1157 if (cpumask_test_cpu(cpu, policy->cpus))
1158 return 0;
1159
1160 down_write(&policy->rwsem);
1161 if (has_target())
1162 cpufreq_stop_governor(policy);
1163
1164 cpumask_set_cpu(cpu, policy->cpus);
1165
1166 if (has_target()) {
1167 ret = cpufreq_start_governor(policy);
1168 if (ret)
1169 pr_err("%s: Failed to start governor\n", __func__);
1170 }
1171 up_write(&policy->rwsem);
1172 return ret;
1173}
1174
1175void refresh_frequency_limits(struct cpufreq_policy *policy)
1176{
1177 if (!policy_is_inactive(policy)) {
1178 pr_debug("updating policy for CPU %u\n", policy->cpu);
1179
1180 cpufreq_set_policy(policy, policy->governor, policy->policy);
1181 }
1182}
1183EXPORT_SYMBOL(refresh_frequency_limits);
1184
1185static void handle_update(struct work_struct *work)
1186{
1187 struct cpufreq_policy *policy =
1188 container_of(work, struct cpufreq_policy, update);
1189
1190 pr_debug("handle_update for cpu %u called\n", policy->cpu);
1191 down_write(&policy->rwsem);
1192 refresh_frequency_limits(policy);
1193 up_write(&policy->rwsem);
1194}
1195
1196static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1197 void *data)
1198{
1199 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1200
1201 schedule_work(&policy->update);
1202 return 0;
1203}
1204
1205static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1206 void *data)
1207{
1208 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1209
1210 schedule_work(&policy->update);
1211 return 0;
1212}
1213
1214static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1215{
1216 struct kobject *kobj;
1217 struct completion *cmp;
1218
1219 down_write(&policy->rwsem);
1220 cpufreq_stats_free_table(policy);
1221 kobj = &policy->kobj;
1222 cmp = &policy->kobj_unregister;
1223 up_write(&policy->rwsem);
1224 kobject_put(kobj);
1225
1226 /*
1227 * We need to make sure that the underlying kobj is
1228 * actually not referenced anymore by anybody before we
1229 * proceed with unloading.
1230 */
1231 pr_debug("waiting for dropping of refcount\n");
1232 wait_for_completion(cmp);
1233 pr_debug("wait complete\n");
1234}
1235
1236static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1237{
1238 struct cpufreq_policy *policy;
1239 struct device *dev = get_cpu_device(cpu);
1240 int ret;
1241
1242 if (!dev)
1243 return NULL;
1244
1245 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1246 if (!policy)
1247 return NULL;
1248
1249 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1250 goto err_free_policy;
1251
1252 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1253 goto err_free_cpumask;
1254
1255 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1256 goto err_free_rcpumask;
1257
1258 init_completion(&policy->kobj_unregister);
1259 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1260 cpufreq_global_kobject, "policy%u", cpu);
1261 if (ret) {
1262 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1263 /*
1264 * The entire policy object will be freed below, but the extra
1265 * memory allocated for the kobject name needs to be freed by
1266 * releasing the kobject.
1267 */
1268 kobject_put(&policy->kobj);
1269 goto err_free_real_cpus;
1270 }
1271
1272 freq_constraints_init(&policy->constraints);
1273
1274 policy->nb_min.notifier_call = cpufreq_notifier_min;
1275 policy->nb_max.notifier_call = cpufreq_notifier_max;
1276
1277 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1278 &policy->nb_min);
1279 if (ret) {
1280 dev_err(dev, "Failed to register MIN QoS notifier: %d (CPU%u)\n",
1281 ret, cpu);
1282 goto err_kobj_remove;
1283 }
1284
1285 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1286 &policy->nb_max);
1287 if (ret) {
1288 dev_err(dev, "Failed to register MAX QoS notifier: %d (CPU%u)\n",
1289 ret, cpu);
1290 goto err_min_qos_notifier;
1291 }
1292
1293 INIT_LIST_HEAD(&policy->policy_list);
1294 init_rwsem(&policy->rwsem);
1295 spin_lock_init(&policy->transition_lock);
1296 init_waitqueue_head(&policy->transition_wait);
1297 INIT_WORK(&policy->update, handle_update);
1298
1299 policy->cpu = cpu;
1300 return policy;
1301
1302err_min_qos_notifier:
1303 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1304 &policy->nb_min);
1305err_kobj_remove:
1306 cpufreq_policy_put_kobj(policy);
1307err_free_real_cpus:
1308 free_cpumask_var(policy->real_cpus);
1309err_free_rcpumask:
1310 free_cpumask_var(policy->related_cpus);
1311err_free_cpumask:
1312 free_cpumask_var(policy->cpus);
1313err_free_policy:
1314 kfree(policy);
1315
1316 return NULL;
1317}
1318
1319static void cpufreq_policy_free(struct cpufreq_policy *policy)
1320{
1321 unsigned long flags;
1322 int cpu;
1323
1324 /*
1325 * The callers must ensure the policy is inactive by now, to avoid any
1326 * races with show()/store() callbacks.
1327 */
1328 if (unlikely(!policy_is_inactive(policy)))
1329 pr_warn("%s: Freeing active policy\n", __func__);
1330
1331 /* Remove policy from list */
1332 write_lock_irqsave(&cpufreq_driver_lock, flags);
1333 list_del(&policy->policy_list);
1334
1335 for_each_cpu(cpu, policy->related_cpus)
1336 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1337 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1338
1339 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1340 &policy->nb_max);
1341 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1342 &policy->nb_min);
1343
1344 /* Cancel any pending policy->update work before freeing the policy. */
1345 cancel_work_sync(&policy->update);
1346
1347 if (policy->max_freq_req) {
1348 /*
1349 * Remove max_freq_req after sending CPUFREQ_REMOVE_POLICY
1350 * notification, since CPUFREQ_CREATE_POLICY notification was
1351 * sent after adding max_freq_req earlier.
1352 */
1353 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1354 CPUFREQ_REMOVE_POLICY, policy);
1355 freq_qos_remove_request(policy->max_freq_req);
1356 }
1357
1358 freq_qos_remove_request(policy->min_freq_req);
1359 kfree(policy->min_freq_req);
1360
1361 cpufreq_policy_put_kobj(policy);
1362 free_cpumask_var(policy->real_cpus);
1363 free_cpumask_var(policy->related_cpus);
1364 free_cpumask_var(policy->cpus);
1365 kfree(policy);
1366}
1367
1368static int cpufreq_online(unsigned int cpu)
1369{
1370 struct cpufreq_policy *policy;
1371 bool new_policy;
1372 unsigned long flags;
1373 unsigned int j;
1374 int ret;
1375
1376 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1377
1378 /* Check if this CPU already has a policy to manage it */
1379 policy = per_cpu(cpufreq_cpu_data, cpu);
1380 if (policy) {
1381 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1382 if (!policy_is_inactive(policy))
1383 return cpufreq_add_policy_cpu(policy, cpu);
1384
1385 /* This is the only online CPU for the policy. Start over. */
1386 new_policy = false;
1387 down_write(&policy->rwsem);
1388 policy->cpu = cpu;
1389 policy->governor = NULL;
1390 } else {
1391 new_policy = true;
1392 policy = cpufreq_policy_alloc(cpu);
1393 if (!policy)
1394 return -ENOMEM;
1395 down_write(&policy->rwsem);
1396 }
1397
1398 if (!new_policy && cpufreq_driver->online) {
1399 /* Recover policy->cpus using related_cpus */
1400 cpumask_copy(policy->cpus, policy->related_cpus);
1401
1402 ret = cpufreq_driver->online(policy);
1403 if (ret) {
1404 pr_debug("%s: %d: initialization failed\n", __func__,
1405 __LINE__);
1406 goto out_exit_policy;
1407 }
1408 } else {
1409 cpumask_copy(policy->cpus, cpumask_of(cpu));
1410
1411 /*
1412 * Call driver. From then on the cpufreq must be able
1413 * to accept all calls to ->verify and ->setpolicy for this CPU.
1414 */
1415 ret = cpufreq_driver->init(policy);
1416 if (ret) {
1417 pr_debug("%s: %d: initialization failed\n", __func__,
1418 __LINE__);
1419 goto out_free_policy;
1420 }
1421
1422 /*
1423 * The initialization has succeeded and the policy is online.
1424 * If there is a problem with its frequency table, take it
1425 * offline and drop it.
1426 */
1427 ret = cpufreq_table_validate_and_sort(policy);
1428 if (ret)
1429 goto out_offline_policy;
1430
1431 /* related_cpus should at least include policy->cpus. */
1432 cpumask_copy(policy->related_cpus, policy->cpus);
1433 }
1434
1435 /*
1436 * affected cpus must always be the one, which are online. We aren't
1437 * managing offline cpus here.
1438 */
1439 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1440
1441 if (new_policy) {
1442 for_each_cpu(j, policy->related_cpus) {
1443 per_cpu(cpufreq_cpu_data, j) = policy;
1444 add_cpu_dev_symlink(policy, j, get_cpu_device(j));
1445 }
1446
1447 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1448 GFP_KERNEL);
1449 if (!policy->min_freq_req) {
1450 ret = -ENOMEM;
1451 goto out_destroy_policy;
1452 }
1453
1454 ret = freq_qos_add_request(&policy->constraints,
1455 policy->min_freq_req, FREQ_QOS_MIN,
1456 FREQ_QOS_MIN_DEFAULT_VALUE);
1457 if (ret < 0) {
1458 /*
1459 * So we don't call freq_qos_remove_request() for an
1460 * uninitialized request.
1461 */
1462 kfree(policy->min_freq_req);
1463 policy->min_freq_req = NULL;
1464 goto out_destroy_policy;
1465 }
1466
1467 /*
1468 * This must be initialized right here to avoid calling
1469 * freq_qos_remove_request() on uninitialized request in case
1470 * of errors.
1471 */
1472 policy->max_freq_req = policy->min_freq_req + 1;
1473
1474 ret = freq_qos_add_request(&policy->constraints,
1475 policy->max_freq_req, FREQ_QOS_MAX,
1476 FREQ_QOS_MAX_DEFAULT_VALUE);
1477 if (ret < 0) {
1478 policy->max_freq_req = NULL;
1479 goto out_destroy_policy;
1480 }
1481
1482 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1483 CPUFREQ_CREATE_POLICY, policy);
1484 }
1485
1486 if (cpufreq_driver->get && has_target()) {
1487 policy->cur = cpufreq_driver->get(policy->cpu);
1488 if (!policy->cur) {
1489 ret = -EIO;
1490 pr_err("%s: ->get() failed\n", __func__);
1491 goto out_destroy_policy;
1492 }
1493 }
1494
1495 /*
1496 * Sometimes boot loaders set CPU frequency to a value outside of
1497 * frequency table present with cpufreq core. In such cases CPU might be
1498 * unstable if it has to run on that frequency for long duration of time
1499 * and so its better to set it to a frequency which is specified in
1500 * freq-table. This also makes cpufreq stats inconsistent as
1501 * cpufreq-stats would fail to register because current frequency of CPU
1502 * isn't found in freq-table.
1503 *
1504 * Because we don't want this change to effect boot process badly, we go
1505 * for the next freq which is >= policy->cur ('cur' must be set by now,
1506 * otherwise we will end up setting freq to lowest of the table as 'cur'
1507 * is initialized to zero).
1508 *
1509 * We are passing target-freq as "policy->cur - 1" otherwise
1510 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1511 * equal to target-freq.
1512 */
1513 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1514 && has_target()) {
1515 unsigned int old_freq = policy->cur;
1516
1517 /* Are we running at unknown frequency ? */
1518 ret = cpufreq_frequency_table_get_index(policy, old_freq);
1519 if (ret == -EINVAL) {
1520 ret = __cpufreq_driver_target(policy, old_freq - 1,
1521 CPUFREQ_RELATION_L);
1522
1523 /*
1524 * Reaching here after boot in a few seconds may not
1525 * mean that system will remain stable at "unknown"
1526 * frequency for longer duration. Hence, a BUG_ON().
1527 */
1528 BUG_ON(ret);
1529 pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
1530 __func__, policy->cpu, old_freq, policy->cur);
1531 }
1532 }
1533
1534 if (new_policy) {
1535 ret = cpufreq_add_dev_interface(policy);
1536 if (ret)
1537 goto out_destroy_policy;
1538
1539 cpufreq_stats_create_table(policy);
1540
1541 write_lock_irqsave(&cpufreq_driver_lock, flags);
1542 list_add(&policy->policy_list, &cpufreq_policy_list);
1543 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1544
1545 /*
1546 * Register with the energy model before
1547 * sugov_eas_rebuild_sd() is called, which will result
1548 * in rebuilding of the sched domains, which should only be done
1549 * once the energy model is properly initialized for the policy
1550 * first.
1551 *
1552 * Also, this should be called before the policy is registered
1553 * with cooling framework.
1554 */
1555 if (cpufreq_driver->register_em)
1556 cpufreq_driver->register_em(policy);
1557 }
1558
1559 ret = cpufreq_init_policy(policy);
1560 if (ret) {
1561 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1562 __func__, cpu, ret);
1563 goto out_destroy_policy;
1564 }
1565
1566 up_write(&policy->rwsem);
1567
1568 kobject_uevent(&policy->kobj, KOBJ_ADD);
1569
1570 /* Callback for handling stuff after policy is ready */
1571 if (cpufreq_driver->ready)
1572 cpufreq_driver->ready(policy);
1573
1574 if (cpufreq_thermal_control_enabled(cpufreq_driver))
1575 policy->cdev = of_cpufreq_cooling_register(policy);
1576
1577 pr_debug("initialization complete\n");
1578
1579 return 0;
1580
1581out_destroy_policy:
1582 for_each_cpu(j, policy->real_cpus)
1583 remove_cpu_dev_symlink(policy, j, get_cpu_device(j));
1584
1585out_offline_policy:
1586 if (cpufreq_driver->offline)
1587 cpufreq_driver->offline(policy);
1588
1589out_exit_policy:
1590 if (cpufreq_driver->exit)
1591 cpufreq_driver->exit(policy);
1592
1593out_free_policy:
1594 cpumask_clear(policy->cpus);
1595 up_write(&policy->rwsem);
1596
1597 cpufreq_policy_free(policy);
1598 return ret;
1599}
1600
1601/**
1602 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1603 * @dev: CPU device.
1604 * @sif: Subsystem interface structure pointer (not used)
1605 */
1606static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1607{
1608 struct cpufreq_policy *policy;
1609 unsigned cpu = dev->id;
1610 int ret;
1611
1612 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1613
1614 if (cpu_online(cpu)) {
1615 ret = cpufreq_online(cpu);
1616 if (ret)
1617 return ret;
1618 }
1619
1620 /* Create sysfs link on CPU registration */
1621 policy = per_cpu(cpufreq_cpu_data, cpu);
1622 if (policy)
1623 add_cpu_dev_symlink(policy, cpu, dev);
1624
1625 return 0;
1626}
1627
1628static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy)
1629{
1630 int ret;
1631
1632 if (has_target())
1633 cpufreq_stop_governor(policy);
1634
1635 cpumask_clear_cpu(cpu, policy->cpus);
1636
1637 if (!policy_is_inactive(policy)) {
1638 /* Nominate a new CPU if necessary. */
1639 if (cpu == policy->cpu)
1640 policy->cpu = cpumask_any(policy->cpus);
1641
1642 /* Start the governor again for the active policy. */
1643 if (has_target()) {
1644 ret = cpufreq_start_governor(policy);
1645 if (ret)
1646 pr_err("%s: Failed to start governor\n", __func__);
1647 }
1648
1649 return;
1650 }
1651
1652 if (has_target())
1653 strscpy(policy->last_governor, policy->governor->name,
1654 CPUFREQ_NAME_LEN);
1655 else
1656 policy->last_policy = policy->policy;
1657
1658 if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1659 cpufreq_cooling_unregister(policy->cdev);
1660 policy->cdev = NULL;
1661 }
1662
1663 if (has_target())
1664 cpufreq_exit_governor(policy);
1665
1666 /*
1667 * Perform the ->offline() during light-weight tear-down, as
1668 * that allows fast recovery when the CPU comes back.
1669 */
1670 if (cpufreq_driver->offline) {
1671 cpufreq_driver->offline(policy);
1672 } else if (cpufreq_driver->exit) {
1673 cpufreq_driver->exit(policy);
1674 policy->freq_table = NULL;
1675 }
1676}
1677
1678static int cpufreq_offline(unsigned int cpu)
1679{
1680 struct cpufreq_policy *policy;
1681
1682 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1683
1684 policy = cpufreq_cpu_get_raw(cpu);
1685 if (!policy) {
1686 pr_debug("%s: No cpu_data found\n", __func__);
1687 return 0;
1688 }
1689
1690 down_write(&policy->rwsem);
1691
1692 __cpufreq_offline(cpu, policy);
1693
1694 up_write(&policy->rwsem);
1695 return 0;
1696}
1697
1698/*
1699 * cpufreq_remove_dev - remove a CPU device
1700 *
1701 * Removes the cpufreq interface for a CPU device.
1702 */
1703static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1704{
1705 unsigned int cpu = dev->id;
1706 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1707
1708 if (!policy)
1709 return;
1710
1711 down_write(&policy->rwsem);
1712
1713 if (cpu_online(cpu))
1714 __cpufreq_offline(cpu, policy);
1715
1716 remove_cpu_dev_symlink(policy, cpu, dev);
1717
1718 if (!cpumask_empty(policy->real_cpus)) {
1719 up_write(&policy->rwsem);
1720 return;
1721 }
1722
1723 /* We did light-weight exit earlier, do full tear down now */
1724 if (cpufreq_driver->offline)
1725 cpufreq_driver->exit(policy);
1726
1727 up_write(&policy->rwsem);
1728
1729 cpufreq_policy_free(policy);
1730}
1731
1732/**
1733 * cpufreq_out_of_sync - Fix up actual and saved CPU frequency difference.
1734 * @policy: Policy managing CPUs.
1735 * @new_freq: New CPU frequency.
1736 *
1737 * Adjust to the current frequency first and clean up later by either calling
1738 * cpufreq_update_policy(), or scheduling handle_update().
1739 */
1740static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1741 unsigned int new_freq)
1742{
1743 struct cpufreq_freqs freqs;
1744
1745 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1746 policy->cur, new_freq);
1747
1748 freqs.old = policy->cur;
1749 freqs.new = new_freq;
1750
1751 cpufreq_freq_transition_begin(policy, &freqs);
1752 cpufreq_freq_transition_end(policy, &freqs, 0);
1753}
1754
1755static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1756{
1757 unsigned int new_freq;
1758
1759 new_freq = cpufreq_driver->get(policy->cpu);
1760 if (!new_freq)
1761 return 0;
1762
1763 /*
1764 * If fast frequency switching is used with the given policy, the check
1765 * against policy->cur is pointless, so skip it in that case.
1766 */
1767 if (policy->fast_switch_enabled || !has_target())
1768 return new_freq;
1769
1770 if (policy->cur != new_freq) {
1771 /*
1772 * For some platforms, the frequency returned by hardware may be
1773 * slightly different from what is provided in the frequency
1774 * table, for example hardware may return 499 MHz instead of 500
1775 * MHz. In such cases it is better to avoid getting into
1776 * unnecessary frequency updates.
1777 */
1778 if (abs(policy->cur - new_freq) < KHZ_PER_MHZ)
1779 return policy->cur;
1780
1781 cpufreq_out_of_sync(policy, new_freq);
1782 if (update)
1783 schedule_work(&policy->update);
1784 }
1785
1786 return new_freq;
1787}
1788
1789/**
1790 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1791 * @cpu: CPU number
1792 *
1793 * This is the last known freq, without actually getting it from the driver.
1794 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1795 */
1796unsigned int cpufreq_quick_get(unsigned int cpu)
1797{
1798 struct cpufreq_policy *policy;
1799 unsigned int ret_freq = 0;
1800 unsigned long flags;
1801
1802 read_lock_irqsave(&cpufreq_driver_lock, flags);
1803
1804 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1805 ret_freq = cpufreq_driver->get(cpu);
1806 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1807 return ret_freq;
1808 }
1809
1810 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1811
1812 policy = cpufreq_cpu_get(cpu);
1813 if (policy) {
1814 ret_freq = policy->cur;
1815 cpufreq_cpu_put(policy);
1816 }
1817
1818 return ret_freq;
1819}
1820EXPORT_SYMBOL(cpufreq_quick_get);
1821
1822/**
1823 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1824 * @cpu: CPU number
1825 *
1826 * Just return the max possible frequency for a given CPU.
1827 */
1828unsigned int cpufreq_quick_get_max(unsigned int cpu)
1829{
1830 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1831 unsigned int ret_freq = 0;
1832
1833 if (policy) {
1834 ret_freq = policy->max;
1835 cpufreq_cpu_put(policy);
1836 }
1837
1838 return ret_freq;
1839}
1840EXPORT_SYMBOL(cpufreq_quick_get_max);
1841
1842/**
1843 * cpufreq_get_hw_max_freq - get the max hardware frequency of the CPU
1844 * @cpu: CPU number
1845 *
1846 * The default return value is the max_freq field of cpuinfo.
1847 */
1848__weak unsigned int cpufreq_get_hw_max_freq(unsigned int cpu)
1849{
1850 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1851 unsigned int ret_freq = 0;
1852
1853 if (policy) {
1854 ret_freq = policy->cpuinfo.max_freq;
1855 cpufreq_cpu_put(policy);
1856 }
1857
1858 return ret_freq;
1859}
1860EXPORT_SYMBOL(cpufreq_get_hw_max_freq);
1861
1862static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1863{
1864 if (unlikely(policy_is_inactive(policy)))
1865 return 0;
1866
1867 return cpufreq_verify_current_freq(policy, true);
1868}
1869
1870/**
1871 * cpufreq_get - get the current CPU frequency (in kHz)
1872 * @cpu: CPU number
1873 *
1874 * Get the CPU current (static) CPU frequency
1875 */
1876unsigned int cpufreq_get(unsigned int cpu)
1877{
1878 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1879 unsigned int ret_freq = 0;
1880
1881 if (policy) {
1882 down_read(&policy->rwsem);
1883 if (cpufreq_driver->get)
1884 ret_freq = __cpufreq_get(policy);
1885 up_read(&policy->rwsem);
1886
1887 cpufreq_cpu_put(policy);
1888 }
1889
1890 return ret_freq;
1891}
1892EXPORT_SYMBOL(cpufreq_get);
1893
1894static struct subsys_interface cpufreq_interface = {
1895 .name = "cpufreq",
1896 .subsys = &cpu_subsys,
1897 .add_dev = cpufreq_add_dev,
1898 .remove_dev = cpufreq_remove_dev,
1899};
1900
1901/*
1902 * In case platform wants some specific frequency to be configured
1903 * during suspend..
1904 */
1905int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1906{
1907 int ret;
1908
1909 if (!policy->suspend_freq) {
1910 pr_debug("%s: suspend_freq not defined\n", __func__);
1911 return 0;
1912 }
1913
1914 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1915 policy->suspend_freq);
1916
1917 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1918 CPUFREQ_RELATION_H);
1919 if (ret)
1920 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1921 __func__, policy->suspend_freq, ret);
1922
1923 return ret;
1924}
1925EXPORT_SYMBOL(cpufreq_generic_suspend);
1926
1927/**
1928 * cpufreq_suspend() - Suspend CPUFreq governors.
1929 *
1930 * Called during system wide Suspend/Hibernate cycles for suspending governors
1931 * as some platforms can't change frequency after this point in suspend cycle.
1932 * Because some of the devices (like: i2c, regulators, etc) they use for
1933 * changing frequency are suspended quickly after this point.
1934 */
1935void cpufreq_suspend(void)
1936{
1937 struct cpufreq_policy *policy;
1938
1939 if (!cpufreq_driver)
1940 return;
1941
1942 if (!has_target() && !cpufreq_driver->suspend)
1943 goto suspend;
1944
1945 pr_debug("%s: Suspending Governors\n", __func__);
1946
1947 for_each_active_policy(policy) {
1948 if (has_target()) {
1949 down_write(&policy->rwsem);
1950 cpufreq_stop_governor(policy);
1951 up_write(&policy->rwsem);
1952 }
1953
1954 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1955 pr_err("%s: Failed to suspend driver: %s\n", __func__,
1956 cpufreq_driver->name);
1957 }
1958
1959suspend:
1960 cpufreq_suspended = true;
1961}
1962
1963/**
1964 * cpufreq_resume() - Resume CPUFreq governors.
1965 *
1966 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1967 * are suspended with cpufreq_suspend().
1968 */
1969void cpufreq_resume(void)
1970{
1971 struct cpufreq_policy *policy;
1972 int ret;
1973
1974 if (!cpufreq_driver)
1975 return;
1976
1977 if (unlikely(!cpufreq_suspended))
1978 return;
1979
1980 cpufreq_suspended = false;
1981
1982 if (!has_target() && !cpufreq_driver->resume)
1983 return;
1984
1985 pr_debug("%s: Resuming Governors\n", __func__);
1986
1987 for_each_active_policy(policy) {
1988 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1989 pr_err("%s: Failed to resume driver: %s\n", __func__,
1990 cpufreq_driver->name);
1991 } else if (has_target()) {
1992 down_write(&policy->rwsem);
1993 ret = cpufreq_start_governor(policy);
1994 up_write(&policy->rwsem);
1995
1996 if (ret)
1997 pr_err("%s: Failed to start governor for CPU%u's policy\n",
1998 __func__, policy->cpu);
1999 }
2000 }
2001}
2002
2003/**
2004 * cpufreq_driver_test_flags - Test cpufreq driver's flags against given ones.
2005 * @flags: Flags to test against the current cpufreq driver's flags.
2006 *
2007 * Assumes that the driver is there, so callers must ensure that this is the
2008 * case.
2009 */
2010bool cpufreq_driver_test_flags(u16 flags)
2011{
2012 return !!(cpufreq_driver->flags & flags);
2013}
2014
2015/**
2016 * cpufreq_get_current_driver - Return the current driver's name.
2017 *
2018 * Return the name string of the currently registered cpufreq driver or NULL if
2019 * none.
2020 */
2021const char *cpufreq_get_current_driver(void)
2022{
2023 if (cpufreq_driver)
2024 return cpufreq_driver->name;
2025
2026 return NULL;
2027}
2028EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
2029
2030/**
2031 * cpufreq_get_driver_data - Return current driver data.
2032 *
2033 * Return the private data of the currently registered cpufreq driver, or NULL
2034 * if no cpufreq driver has been registered.
2035 */
2036void *cpufreq_get_driver_data(void)
2037{
2038 if (cpufreq_driver)
2039 return cpufreq_driver->driver_data;
2040
2041 return NULL;
2042}
2043EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
2044
2045/*********************************************************************
2046 * NOTIFIER LISTS INTERFACE *
2047 *********************************************************************/
2048
2049/**
2050 * cpufreq_register_notifier - Register a notifier with cpufreq.
2051 * @nb: notifier function to register.
2052 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2053 *
2054 * Add a notifier to one of two lists: either a list of notifiers that run on
2055 * clock rate changes (once before and once after every transition), or a list
2056 * of notifiers that ron on cpufreq policy changes.
2057 *
2058 * This function may sleep and it has the same return values as
2059 * blocking_notifier_chain_register().
2060 */
2061int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
2062{
2063 int ret;
2064
2065 if (cpufreq_disabled())
2066 return -EINVAL;
2067
2068 switch (list) {
2069 case CPUFREQ_TRANSITION_NOTIFIER:
2070 mutex_lock(&cpufreq_fast_switch_lock);
2071
2072 if (cpufreq_fast_switch_count > 0) {
2073 mutex_unlock(&cpufreq_fast_switch_lock);
2074 return -EBUSY;
2075 }
2076 ret = srcu_notifier_chain_register(
2077 &cpufreq_transition_notifier_list, nb);
2078 if (!ret)
2079 cpufreq_fast_switch_count--;
2080
2081 mutex_unlock(&cpufreq_fast_switch_lock);
2082 break;
2083 case CPUFREQ_POLICY_NOTIFIER:
2084 ret = blocking_notifier_chain_register(
2085 &cpufreq_policy_notifier_list, nb);
2086 break;
2087 default:
2088 ret = -EINVAL;
2089 }
2090
2091 return ret;
2092}
2093EXPORT_SYMBOL(cpufreq_register_notifier);
2094
2095/**
2096 * cpufreq_unregister_notifier - Unregister a notifier from cpufreq.
2097 * @nb: notifier block to be unregistered.
2098 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER.
2099 *
2100 * Remove a notifier from one of the cpufreq notifier lists.
2101 *
2102 * This function may sleep and it has the same return values as
2103 * blocking_notifier_chain_unregister().
2104 */
2105int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
2106{
2107 int ret;
2108
2109 if (cpufreq_disabled())
2110 return -EINVAL;
2111
2112 switch (list) {
2113 case CPUFREQ_TRANSITION_NOTIFIER:
2114 mutex_lock(&cpufreq_fast_switch_lock);
2115
2116 ret = srcu_notifier_chain_unregister(
2117 &cpufreq_transition_notifier_list, nb);
2118 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
2119 cpufreq_fast_switch_count++;
2120
2121 mutex_unlock(&cpufreq_fast_switch_lock);
2122 break;
2123 case CPUFREQ_POLICY_NOTIFIER:
2124 ret = blocking_notifier_chain_unregister(
2125 &cpufreq_policy_notifier_list, nb);
2126 break;
2127 default:
2128 ret = -EINVAL;
2129 }
2130
2131 return ret;
2132}
2133EXPORT_SYMBOL(cpufreq_unregister_notifier);
2134
2135
2136/*********************************************************************
2137 * GOVERNORS *
2138 *********************************************************************/
2139
2140/**
2141 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
2142 * @policy: cpufreq policy to switch the frequency for.
2143 * @target_freq: New frequency to set (may be approximate).
2144 *
2145 * Carry out a fast frequency switch without sleeping.
2146 *
2147 * The driver's ->fast_switch() callback invoked by this function must be
2148 * suitable for being called from within RCU-sched read-side critical sections
2149 * and it is expected to select the minimum available frequency greater than or
2150 * equal to @target_freq (CPUFREQ_RELATION_L).
2151 *
2152 * This function must not be called if policy->fast_switch_enabled is unset.
2153 *
2154 * Governors calling this function must guarantee that it will never be invoked
2155 * twice in parallel for the same policy and that it will never be called in
2156 * parallel with either ->target() or ->target_index() for the same policy.
2157 *
2158 * Returns the actual frequency set for the CPU.
2159 *
2160 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2161 * error condition, the hardware configuration must be preserved.
2162 */
2163unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2164 unsigned int target_freq)
2165{
2166 unsigned int freq;
2167 int cpu;
2168
2169 target_freq = clamp_val(target_freq, policy->min, policy->max);
2170 freq = cpufreq_driver->fast_switch(policy, target_freq);
2171
2172 if (!freq)
2173 return 0;
2174
2175 policy->cur = freq;
2176 arch_set_freq_scale(policy->related_cpus, freq,
2177 arch_scale_freq_ref(policy->cpu));
2178 cpufreq_stats_record_transition(policy, freq);
2179
2180 if (trace_cpu_frequency_enabled()) {
2181 for_each_cpu(cpu, policy->cpus)
2182 trace_cpu_frequency(freq, cpu);
2183 }
2184
2185 return freq;
2186}
2187EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2188
2189/**
2190 * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
2191 * @cpu: Target CPU.
2192 * @min_perf: Minimum (required) performance level (units of @capacity).
2193 * @target_perf: Target (desired) performance level (units of @capacity).
2194 * @capacity: Capacity of the target CPU.
2195 *
2196 * Carry out a fast performance level switch of @cpu without sleeping.
2197 *
2198 * The driver's ->adjust_perf() callback invoked by this function must be
2199 * suitable for being called from within RCU-sched read-side critical sections
2200 * and it is expected to select a suitable performance level equal to or above
2201 * @min_perf and preferably equal to or below @target_perf.
2202 *
2203 * This function must not be called if policy->fast_switch_enabled is unset.
2204 *
2205 * Governors calling this function must guarantee that it will never be invoked
2206 * twice in parallel for the same CPU and that it will never be called in
2207 * parallel with either ->target() or ->target_index() or ->fast_switch() for
2208 * the same CPU.
2209 */
2210void cpufreq_driver_adjust_perf(unsigned int cpu,
2211 unsigned long min_perf,
2212 unsigned long target_perf,
2213 unsigned long capacity)
2214{
2215 cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
2216}
2217
2218/**
2219 * cpufreq_driver_has_adjust_perf - Check "direct fast switch" callback.
2220 *
2221 * Return 'true' if the ->adjust_perf callback is present for the
2222 * current driver or 'false' otherwise.
2223 */
2224bool cpufreq_driver_has_adjust_perf(void)
2225{
2226 return !!cpufreq_driver->adjust_perf;
2227}
2228
2229/* Must set freqs->new to intermediate frequency */
2230static int __target_intermediate(struct cpufreq_policy *policy,
2231 struct cpufreq_freqs *freqs, int index)
2232{
2233 int ret;
2234
2235 freqs->new = cpufreq_driver->get_intermediate(policy, index);
2236
2237 /* We don't need to switch to intermediate freq */
2238 if (!freqs->new)
2239 return 0;
2240
2241 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2242 __func__, policy->cpu, freqs->old, freqs->new);
2243
2244 cpufreq_freq_transition_begin(policy, freqs);
2245 ret = cpufreq_driver->target_intermediate(policy, index);
2246 cpufreq_freq_transition_end(policy, freqs, ret);
2247
2248 if (ret)
2249 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2250 __func__, ret);
2251
2252 return ret;
2253}
2254
2255static int __target_index(struct cpufreq_policy *policy, int index)
2256{
2257 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2258 unsigned int restore_freq, intermediate_freq = 0;
2259 unsigned int newfreq = policy->freq_table[index].frequency;
2260 int retval = -EINVAL;
2261 bool notify;
2262
2263 if (newfreq == policy->cur)
2264 return 0;
2265
2266 /* Save last value to restore later on errors */
2267 restore_freq = policy->cur;
2268
2269 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2270 if (notify) {
2271 /* Handle switching to intermediate frequency */
2272 if (cpufreq_driver->get_intermediate) {
2273 retval = __target_intermediate(policy, &freqs, index);
2274 if (retval)
2275 return retval;
2276
2277 intermediate_freq = freqs.new;
2278 /* Set old freq to intermediate */
2279 if (intermediate_freq)
2280 freqs.old = freqs.new;
2281 }
2282
2283 freqs.new = newfreq;
2284 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2285 __func__, policy->cpu, freqs.old, freqs.new);
2286
2287 cpufreq_freq_transition_begin(policy, &freqs);
2288 }
2289
2290 retval = cpufreq_driver->target_index(policy, index);
2291 if (retval)
2292 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2293 retval);
2294
2295 if (notify) {
2296 cpufreq_freq_transition_end(policy, &freqs, retval);
2297
2298 /*
2299 * Failed after setting to intermediate freq? Driver should have
2300 * reverted back to initial frequency and so should we. Check
2301 * here for intermediate_freq instead of get_intermediate, in
2302 * case we haven't switched to intermediate freq at all.
2303 */
2304 if (unlikely(retval && intermediate_freq)) {
2305 freqs.old = intermediate_freq;
2306 freqs.new = restore_freq;
2307 cpufreq_freq_transition_begin(policy, &freqs);
2308 cpufreq_freq_transition_end(policy, &freqs, 0);
2309 }
2310 }
2311
2312 return retval;
2313}
2314
2315int __cpufreq_driver_target(struct cpufreq_policy *policy,
2316 unsigned int target_freq,
2317 unsigned int relation)
2318{
2319 unsigned int old_target_freq = target_freq;
2320
2321 if (cpufreq_disabled())
2322 return -ENODEV;
2323
2324 target_freq = __resolve_freq(policy, target_freq, relation);
2325
2326 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2327 policy->cpu, target_freq, relation, old_target_freq);
2328
2329 /*
2330 * This might look like a redundant call as we are checking it again
2331 * after finding index. But it is left intentionally for cases where
2332 * exactly same freq is called again and so we can save on few function
2333 * calls.
2334 */
2335 if (target_freq == policy->cur &&
2336 !(cpufreq_driver->flags & CPUFREQ_NEED_UPDATE_LIMITS))
2337 return 0;
2338
2339 if (cpufreq_driver->target) {
2340 /*
2341 * If the driver hasn't setup a single inefficient frequency,
2342 * it's unlikely it knows how to decode CPUFREQ_RELATION_E.
2343 */
2344 if (!policy->efficiencies_available)
2345 relation &= ~CPUFREQ_RELATION_E;
2346
2347 return cpufreq_driver->target(policy, target_freq, relation);
2348 }
2349
2350 if (!cpufreq_driver->target_index)
2351 return -EINVAL;
2352
2353 return __target_index(policy, policy->cached_resolved_idx);
2354}
2355EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2356
2357int cpufreq_driver_target(struct cpufreq_policy *policy,
2358 unsigned int target_freq,
2359 unsigned int relation)
2360{
2361 int ret;
2362
2363 down_write(&policy->rwsem);
2364
2365 ret = __cpufreq_driver_target(policy, target_freq, relation);
2366
2367 up_write(&policy->rwsem);
2368
2369 return ret;
2370}
2371EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2372
2373__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2374{
2375 return NULL;
2376}
2377
2378static int cpufreq_init_governor(struct cpufreq_policy *policy)
2379{
2380 int ret;
2381
2382 /* Don't start any governor operations if we are entering suspend */
2383 if (cpufreq_suspended)
2384 return 0;
2385 /*
2386 * Governor might not be initiated here if ACPI _PPC changed
2387 * notification happened, so check it.
2388 */
2389 if (!policy->governor)
2390 return -EINVAL;
2391
2392 /* Platform doesn't want dynamic frequency switching ? */
2393 if (policy->governor->flags & CPUFREQ_GOV_DYNAMIC_SWITCHING &&
2394 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2395 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2396
2397 if (gov) {
2398 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2399 policy->governor->name, gov->name);
2400 policy->governor = gov;
2401 } else {
2402 return -EINVAL;
2403 }
2404 }
2405
2406 if (!try_module_get(policy->governor->owner))
2407 return -EINVAL;
2408
2409 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2410
2411 if (policy->governor->init) {
2412 ret = policy->governor->init(policy);
2413 if (ret) {
2414 module_put(policy->governor->owner);
2415 return ret;
2416 }
2417 }
2418
2419 policy->strict_target = !!(policy->governor->flags & CPUFREQ_GOV_STRICT_TARGET);
2420
2421 return 0;
2422}
2423
2424static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2425{
2426 if (cpufreq_suspended || !policy->governor)
2427 return;
2428
2429 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2430
2431 if (policy->governor->exit)
2432 policy->governor->exit(policy);
2433
2434 module_put(policy->governor->owner);
2435}
2436
2437int cpufreq_start_governor(struct cpufreq_policy *policy)
2438{
2439 int ret;
2440
2441 if (cpufreq_suspended)
2442 return 0;
2443
2444 if (!policy->governor)
2445 return -EINVAL;
2446
2447 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2448
2449 if (cpufreq_driver->get)
2450 cpufreq_verify_current_freq(policy, false);
2451
2452 if (policy->governor->start) {
2453 ret = policy->governor->start(policy);
2454 if (ret)
2455 return ret;
2456 }
2457
2458 if (policy->governor->limits)
2459 policy->governor->limits(policy);
2460
2461 return 0;
2462}
2463
2464void cpufreq_stop_governor(struct cpufreq_policy *policy)
2465{
2466 if (cpufreq_suspended || !policy->governor)
2467 return;
2468
2469 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2470
2471 if (policy->governor->stop)
2472 policy->governor->stop(policy);
2473}
2474
2475static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2476{
2477 if (cpufreq_suspended || !policy->governor)
2478 return;
2479
2480 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2481
2482 if (policy->governor->limits)
2483 policy->governor->limits(policy);
2484}
2485
2486int cpufreq_register_governor(struct cpufreq_governor *governor)
2487{
2488 int err;
2489
2490 if (!governor)
2491 return -EINVAL;
2492
2493 if (cpufreq_disabled())
2494 return -ENODEV;
2495
2496 mutex_lock(&cpufreq_governor_mutex);
2497
2498 err = -EBUSY;
2499 if (!find_governor(governor->name)) {
2500 err = 0;
2501 list_add(&governor->governor_list, &cpufreq_governor_list);
2502 }
2503
2504 mutex_unlock(&cpufreq_governor_mutex);
2505 return err;
2506}
2507EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2508
2509void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2510{
2511 struct cpufreq_policy *policy;
2512 unsigned long flags;
2513
2514 if (!governor)
2515 return;
2516
2517 if (cpufreq_disabled())
2518 return;
2519
2520 /* clear last_governor for all inactive policies */
2521 read_lock_irqsave(&cpufreq_driver_lock, flags);
2522 for_each_inactive_policy(policy) {
2523 if (!strcmp(policy->last_governor, governor->name)) {
2524 policy->governor = NULL;
2525 strcpy(policy->last_governor, "\0");
2526 }
2527 }
2528 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2529
2530 mutex_lock(&cpufreq_governor_mutex);
2531 list_del(&governor->governor_list);
2532 mutex_unlock(&cpufreq_governor_mutex);
2533}
2534EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2535
2536
2537/*********************************************************************
2538 * POLICY INTERFACE *
2539 *********************************************************************/
2540
2541/**
2542 * cpufreq_get_policy - get the current cpufreq_policy
2543 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2544 * is written
2545 * @cpu: CPU to find the policy for
2546 *
2547 * Reads the current cpufreq policy.
2548 */
2549int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2550{
2551 struct cpufreq_policy *cpu_policy;
2552 if (!policy)
2553 return -EINVAL;
2554
2555 cpu_policy = cpufreq_cpu_get(cpu);
2556 if (!cpu_policy)
2557 return -EINVAL;
2558
2559 memcpy(policy, cpu_policy, sizeof(*policy));
2560
2561 cpufreq_cpu_put(cpu_policy);
2562 return 0;
2563}
2564EXPORT_SYMBOL(cpufreq_get_policy);
2565
2566/**
2567 * cpufreq_set_policy - Modify cpufreq policy parameters.
2568 * @policy: Policy object to modify.
2569 * @new_gov: Policy governor pointer.
2570 * @new_pol: Policy value (for drivers with built-in governors).
2571 *
2572 * Invoke the cpufreq driver's ->verify() callback to sanity-check the frequency
2573 * limits to be set for the policy, update @policy with the verified limits
2574 * values and either invoke the driver's ->setpolicy() callback (if present) or
2575 * carry out a governor update for @policy. That is, run the current governor's
2576 * ->limits() callback (if @new_gov points to the same object as the one in
2577 * @policy) or replace the governor for @policy with @new_gov.
2578 *
2579 * The cpuinfo part of @policy is not updated by this function.
2580 */
2581static int cpufreq_set_policy(struct cpufreq_policy *policy,
2582 struct cpufreq_governor *new_gov,
2583 unsigned int new_pol)
2584{
2585 struct cpufreq_policy_data new_data;
2586 struct cpufreq_governor *old_gov;
2587 int ret;
2588
2589 memcpy(&new_data.cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2590 new_data.freq_table = policy->freq_table;
2591 new_data.cpu = policy->cpu;
2592 /*
2593 * PM QoS framework collects all the requests from users and provide us
2594 * the final aggregated value here.
2595 */
2596 new_data.min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2597 new_data.max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2598
2599 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2600 new_data.cpu, new_data.min, new_data.max);
2601
2602 /*
2603 * Verify that the CPU speed can be set within these limits and make sure
2604 * that min <= max.
2605 */
2606 ret = cpufreq_driver->verify(&new_data);
2607 if (ret)
2608 return ret;
2609
2610 /*
2611 * Resolve policy min/max to available frequencies. It ensures
2612 * no frequency resolution will neither overshoot the requested maximum
2613 * nor undershoot the requested minimum.
2614 */
2615 policy->min = new_data.min;
2616 policy->max = new_data.max;
2617 policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
2618 policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
2619 trace_cpu_frequency_limits(policy);
2620
2621 policy->cached_target_freq = UINT_MAX;
2622
2623 pr_debug("new min and max freqs are %u - %u kHz\n",
2624 policy->min, policy->max);
2625
2626 if (cpufreq_driver->setpolicy) {
2627 policy->policy = new_pol;
2628 pr_debug("setting range\n");
2629 return cpufreq_driver->setpolicy(policy);
2630 }
2631
2632 if (new_gov == policy->governor) {
2633 pr_debug("governor limits update\n");
2634 cpufreq_governor_limits(policy);
2635 return 0;
2636 }
2637
2638 pr_debug("governor switch\n");
2639
2640 /* save old, working values */
2641 old_gov = policy->governor;
2642 /* end old governor */
2643 if (old_gov) {
2644 cpufreq_stop_governor(policy);
2645 cpufreq_exit_governor(policy);
2646 }
2647
2648 /* start new governor */
2649 policy->governor = new_gov;
2650 ret = cpufreq_init_governor(policy);
2651 if (!ret) {
2652 ret = cpufreq_start_governor(policy);
2653 if (!ret) {
2654 pr_debug("governor change\n");
2655 return 0;
2656 }
2657 cpufreq_exit_governor(policy);
2658 }
2659
2660 /* new governor failed, so re-start old one */
2661 pr_debug("starting governor %s failed\n", policy->governor->name);
2662 if (old_gov) {
2663 policy->governor = old_gov;
2664 if (cpufreq_init_governor(policy))
2665 policy->governor = NULL;
2666 else
2667 cpufreq_start_governor(policy);
2668 }
2669
2670 return ret;
2671}
2672
2673/**
2674 * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2675 * @cpu: CPU to re-evaluate the policy for.
2676 *
2677 * Update the current frequency for the cpufreq policy of @cpu and use
2678 * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2679 * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2680 * for the policy in question, among other things.
2681 */
2682void cpufreq_update_policy(unsigned int cpu)
2683{
2684 struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2685
2686 if (!policy)
2687 return;
2688
2689 /*
2690 * BIOS might change freq behind our back
2691 * -> ask driver for current freq and notify governors about a change
2692 */
2693 if (cpufreq_driver->get && has_target() &&
2694 (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2695 goto unlock;
2696
2697 refresh_frequency_limits(policy);
2698
2699unlock:
2700 cpufreq_cpu_release(policy);
2701}
2702EXPORT_SYMBOL(cpufreq_update_policy);
2703
2704/**
2705 * cpufreq_update_limits - Update policy limits for a given CPU.
2706 * @cpu: CPU to update the policy limits for.
2707 *
2708 * Invoke the driver's ->update_limits callback if present or call
2709 * cpufreq_update_policy() for @cpu.
2710 */
2711void cpufreq_update_limits(unsigned int cpu)
2712{
2713 if (cpufreq_driver->update_limits)
2714 cpufreq_driver->update_limits(cpu);
2715 else
2716 cpufreq_update_policy(cpu);
2717}
2718EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2719
2720/*********************************************************************
2721 * BOOST *
2722 *********************************************************************/
2723static int cpufreq_boost_set_sw(struct cpufreq_policy *policy, int state)
2724{
2725 int ret;
2726
2727 if (!policy->freq_table)
2728 return -ENXIO;
2729
2730 ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
2731 if (ret) {
2732 pr_err("%s: Policy frequency update failed\n", __func__);
2733 return ret;
2734 }
2735
2736 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2737 if (ret < 0)
2738 return ret;
2739
2740 return 0;
2741}
2742
2743int cpufreq_boost_trigger_state(int state)
2744{
2745 struct cpufreq_policy *policy;
2746 unsigned long flags;
2747 int ret = 0;
2748
2749 if (cpufreq_driver->boost_enabled == state)
2750 return 0;
2751
2752 write_lock_irqsave(&cpufreq_driver_lock, flags);
2753 cpufreq_driver->boost_enabled = state;
2754 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2755
2756 cpus_read_lock();
2757 for_each_active_policy(policy) {
2758 ret = cpufreq_driver->set_boost(policy, state);
2759 if (ret)
2760 goto err_reset_state;
2761
2762 policy->boost_enabled = state;
2763 }
2764 cpus_read_unlock();
2765
2766 return 0;
2767
2768err_reset_state:
2769 cpus_read_unlock();
2770
2771 write_lock_irqsave(&cpufreq_driver_lock, flags);
2772 cpufreq_driver->boost_enabled = !state;
2773 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2774
2775 pr_err("%s: Cannot %s BOOST\n",
2776 __func__, state ? "enable" : "disable");
2777
2778 return ret;
2779}
2780
2781static bool cpufreq_boost_supported(void)
2782{
2783 return cpufreq_driver->set_boost;
2784}
2785
2786static int create_boost_sysfs_file(void)
2787{
2788 int ret;
2789
2790 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2791 if (ret)
2792 pr_err("%s: cannot register global BOOST sysfs file\n",
2793 __func__);
2794
2795 return ret;
2796}
2797
2798static void remove_boost_sysfs_file(void)
2799{
2800 if (cpufreq_boost_supported())
2801 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2802}
2803
2804int cpufreq_enable_boost_support(void)
2805{
2806 if (!cpufreq_driver)
2807 return -EINVAL;
2808
2809 if (cpufreq_boost_supported())
2810 return 0;
2811
2812 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2813
2814 /* This will get removed on driver unregister */
2815 return create_boost_sysfs_file();
2816}
2817EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2818
2819int cpufreq_boost_enabled(void)
2820{
2821 return cpufreq_driver->boost_enabled;
2822}
2823EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2824
2825/*********************************************************************
2826 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2827 *********************************************************************/
2828static enum cpuhp_state hp_online;
2829
2830static int cpuhp_cpufreq_online(unsigned int cpu)
2831{
2832 cpufreq_online(cpu);
2833
2834 return 0;
2835}
2836
2837static int cpuhp_cpufreq_offline(unsigned int cpu)
2838{
2839 cpufreq_offline(cpu);
2840
2841 return 0;
2842}
2843
2844/**
2845 * cpufreq_register_driver - register a CPU Frequency driver
2846 * @driver_data: A struct cpufreq_driver containing the values#
2847 * submitted by the CPU Frequency driver.
2848 *
2849 * Registers a CPU Frequency driver to this core code. This code
2850 * returns zero on success, -EEXIST when another driver got here first
2851 * (and isn't unregistered in the meantime).
2852 *
2853 */
2854int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2855{
2856 unsigned long flags;
2857 int ret;
2858
2859 if (cpufreq_disabled())
2860 return -ENODEV;
2861
2862 /*
2863 * The cpufreq core depends heavily on the availability of device
2864 * structure, make sure they are available before proceeding further.
2865 */
2866 if (!get_cpu_device(0))
2867 return -EPROBE_DEFER;
2868
2869 if (!driver_data || !driver_data->verify || !driver_data->init ||
2870 !(driver_data->setpolicy || driver_data->target_index ||
2871 driver_data->target) ||
2872 (driver_data->setpolicy && (driver_data->target_index ||
2873 driver_data->target)) ||
2874 (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2875 (!driver_data->online != !driver_data->offline) ||
2876 (driver_data->adjust_perf && !driver_data->fast_switch))
2877 return -EINVAL;
2878
2879 pr_debug("trying to register driver %s\n", driver_data->name);
2880
2881 /* Protect against concurrent CPU online/offline. */
2882 cpus_read_lock();
2883
2884 write_lock_irqsave(&cpufreq_driver_lock, flags);
2885 if (cpufreq_driver) {
2886 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2887 ret = -EEXIST;
2888 goto out;
2889 }
2890 cpufreq_driver = driver_data;
2891 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2892
2893 /*
2894 * Mark support for the scheduler's frequency invariance engine for
2895 * drivers that implement target(), target_index() or fast_switch().
2896 */
2897 if (!cpufreq_driver->setpolicy) {
2898 static_branch_enable_cpuslocked(&cpufreq_freq_invariance);
2899 pr_debug("supports frequency invariance");
2900 }
2901
2902 if (driver_data->setpolicy)
2903 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2904
2905 if (cpufreq_boost_supported()) {
2906 ret = create_boost_sysfs_file();
2907 if (ret)
2908 goto err_null_driver;
2909 }
2910
2911 ret = subsys_interface_register(&cpufreq_interface);
2912 if (ret)
2913 goto err_boost_unreg;
2914
2915 if (unlikely(list_empty(&cpufreq_policy_list))) {
2916 /* if all ->init() calls failed, unregister */
2917 ret = -ENODEV;
2918 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2919 driver_data->name);
2920 goto err_if_unreg;
2921 }
2922
2923 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2924 "cpufreq:online",
2925 cpuhp_cpufreq_online,
2926 cpuhp_cpufreq_offline);
2927 if (ret < 0)
2928 goto err_if_unreg;
2929 hp_online = ret;
2930 ret = 0;
2931
2932 pr_debug("driver %s up and running\n", driver_data->name);
2933 goto out;
2934
2935err_if_unreg:
2936 subsys_interface_unregister(&cpufreq_interface);
2937err_boost_unreg:
2938 remove_boost_sysfs_file();
2939err_null_driver:
2940 write_lock_irqsave(&cpufreq_driver_lock, flags);
2941 cpufreq_driver = NULL;
2942 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2943out:
2944 cpus_read_unlock();
2945 return ret;
2946}
2947EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2948
2949/*
2950 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2951 *
2952 * Unregister the current CPUFreq driver. Only call this if you have
2953 * the right to do so, i.e. if you have succeeded in initialising before!
2954 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2955 * currently not initialised.
2956 */
2957void cpufreq_unregister_driver(struct cpufreq_driver *driver)
2958{
2959 unsigned long flags;
2960
2961 if (WARN_ON(!cpufreq_driver || (driver != cpufreq_driver)))
2962 return;
2963
2964 pr_debug("unregistering driver %s\n", driver->name);
2965
2966 /* Protect against concurrent cpu hotplug */
2967 cpus_read_lock();
2968 subsys_interface_unregister(&cpufreq_interface);
2969 remove_boost_sysfs_file();
2970 static_branch_disable_cpuslocked(&cpufreq_freq_invariance);
2971 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2972
2973 write_lock_irqsave(&cpufreq_driver_lock, flags);
2974
2975 cpufreq_driver = NULL;
2976
2977 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2978 cpus_read_unlock();
2979}
2980EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2981
2982static int __init cpufreq_core_init(void)
2983{
2984 struct cpufreq_governor *gov = cpufreq_default_governor();
2985 struct device *dev_root;
2986
2987 if (cpufreq_disabled())
2988 return -ENODEV;
2989
2990 dev_root = bus_get_dev_root(&cpu_subsys);
2991 if (dev_root) {
2992 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &dev_root->kobj);
2993 put_device(dev_root);
2994 }
2995 BUG_ON(!cpufreq_global_kobject);
2996
2997 if (!strlen(default_governor))
2998 strscpy(default_governor, gov->name, CPUFREQ_NAME_LEN);
2999
3000 return 0;
3001}
3002module_param(off, int, 0444);
3003module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
3004core_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 <trace/events/power.h>
32
33static LIST_HEAD(cpufreq_policy_list);
34
35/* Macros to iterate over CPU policies */
36#define for_each_suitable_policy(__policy, __active) \
37 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
38 if ((__active) == !policy_is_inactive(__policy))
39
40#define for_each_active_policy(__policy) \
41 for_each_suitable_policy(__policy, true)
42#define for_each_inactive_policy(__policy) \
43 for_each_suitable_policy(__policy, false)
44
45#define for_each_policy(__policy) \
46 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
47
48/* Iterate over governors */
49static LIST_HEAD(cpufreq_governor_list);
50#define for_each_governor(__governor) \
51 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
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
62/* Flag to suspend/resume CPUFreq governors */
63static bool cpufreq_suspended;
64
65static inline bool has_target(void)
66{
67 return cpufreq_driver->target_index || cpufreq_driver->target;
68}
69
70/* internal prototypes */
71static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
72static int cpufreq_init_governor(struct cpufreq_policy *policy);
73static void cpufreq_exit_governor(struct cpufreq_policy *policy);
74static int cpufreq_start_governor(struct cpufreq_policy *policy);
75static void cpufreq_stop_governor(struct cpufreq_policy *policy);
76static void cpufreq_governor_limits(struct cpufreq_policy *policy);
77
78/**
79 * Two notifier lists: the "policy" list is involved in the
80 * validation process for a new CPU frequency policy; the
81 * "transition" list for kernel code that needs to handle
82 * changes to devices when the CPU clock speed changes.
83 * The mutex locks both lists.
84 */
85static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
86SRCU_NOTIFIER_HEAD_STATIC(cpufreq_transition_notifier_list);
87
88static int off __read_mostly;
89static int cpufreq_disabled(void)
90{
91 return off;
92}
93void disable_cpufreq(void)
94{
95 off = 1;
96}
97static DEFINE_MUTEX(cpufreq_governor_mutex);
98
99bool have_governor_per_policy(void)
100{
101 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
102}
103EXPORT_SYMBOL_GPL(have_governor_per_policy);
104
105struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
106{
107 if (have_governor_per_policy())
108 return &policy->kobj;
109 else
110 return cpufreq_global_kobject;
111}
112EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
113
114static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
115{
116 u64 idle_time;
117 u64 cur_wall_time;
118 u64 busy_time;
119
120 cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());
121
122 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
123 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
124 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
125 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
126 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
127 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
128
129 idle_time = cur_wall_time - busy_time;
130 if (wall)
131 *wall = div_u64(cur_wall_time, NSEC_PER_USEC);
132
133 return div_u64(idle_time, NSEC_PER_USEC);
134}
135
136u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
137{
138 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
139
140 if (idle_time == -1ULL)
141 return get_cpu_idle_time_jiffy(cpu, wall);
142 else if (!io_busy)
143 idle_time += get_cpu_iowait_time_us(cpu, wall);
144
145 return idle_time;
146}
147EXPORT_SYMBOL_GPL(get_cpu_idle_time);
148
149__weak void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
150 unsigned long max_freq)
151{
152}
153EXPORT_SYMBOL_GPL(arch_set_freq_scale);
154
155/*
156 * This is a generic cpufreq init() routine which can be used by cpufreq
157 * drivers of SMP systems. It will do following:
158 * - validate & show freq table passed
159 * - set policies transition latency
160 * - policy->cpus with all possible CPUs
161 */
162void cpufreq_generic_init(struct cpufreq_policy *policy,
163 struct cpufreq_frequency_table *table,
164 unsigned int transition_latency)
165{
166 policy->freq_table = table;
167 policy->cpuinfo.transition_latency = transition_latency;
168
169 /*
170 * The driver only supports the SMP configuration where all processors
171 * share the clock and voltage and clock.
172 */
173 cpumask_setall(policy->cpus);
174}
175EXPORT_SYMBOL_GPL(cpufreq_generic_init);
176
177struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
178{
179 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
180
181 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
182}
183EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
184
185unsigned int cpufreq_generic_get(unsigned int cpu)
186{
187 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
188
189 if (!policy || IS_ERR(policy->clk)) {
190 pr_err("%s: No %s associated to cpu: %d\n",
191 __func__, policy ? "clk" : "policy", cpu);
192 return 0;
193 }
194
195 return clk_get_rate(policy->clk) / 1000;
196}
197EXPORT_SYMBOL_GPL(cpufreq_generic_get);
198
199/**
200 * cpufreq_cpu_get - Return policy for a CPU and mark it as busy.
201 * @cpu: CPU to find the policy for.
202 *
203 * Call cpufreq_cpu_get_raw() to obtain a cpufreq policy for @cpu and increment
204 * the kobject reference counter of that policy. Return a valid policy on
205 * success or NULL on failure.
206 *
207 * The policy returned by this function has to be released with the help of
208 * cpufreq_cpu_put() to balance its kobject reference counter properly.
209 */
210struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
211{
212 struct cpufreq_policy *policy = NULL;
213 unsigned long flags;
214
215 if (WARN_ON(cpu >= nr_cpu_ids))
216 return NULL;
217
218 /* get the cpufreq driver */
219 read_lock_irqsave(&cpufreq_driver_lock, flags);
220
221 if (cpufreq_driver) {
222 /* get the CPU */
223 policy = cpufreq_cpu_get_raw(cpu);
224 if (policy)
225 kobject_get(&policy->kobj);
226 }
227
228 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
229
230 return policy;
231}
232EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
233
234/**
235 * cpufreq_cpu_put - Decrement kobject usage counter for cpufreq policy.
236 * @policy: cpufreq policy returned by cpufreq_cpu_get().
237 */
238void cpufreq_cpu_put(struct cpufreq_policy *policy)
239{
240 kobject_put(&policy->kobj);
241}
242EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
243
244/**
245 * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
246 * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
247 */
248void cpufreq_cpu_release(struct cpufreq_policy *policy)
249{
250 if (WARN_ON(!policy))
251 return;
252
253 lockdep_assert_held(&policy->rwsem);
254
255 up_write(&policy->rwsem);
256
257 cpufreq_cpu_put(policy);
258}
259
260/**
261 * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
262 * @cpu: CPU to find the policy for.
263 *
264 * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
265 * if the policy returned by it is not NULL, acquire its rwsem for writing.
266 * Return the policy if it is active or release it and return NULL otherwise.
267 *
268 * The policy returned by this function has to be released with the help of
269 * cpufreq_cpu_release() in order to release its rwsem and balance its usage
270 * counter properly.
271 */
272struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
273{
274 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
275
276 if (!policy)
277 return NULL;
278
279 down_write(&policy->rwsem);
280
281 if (policy_is_inactive(policy)) {
282 cpufreq_cpu_release(policy);
283 return NULL;
284 }
285
286 return policy;
287}
288
289/*********************************************************************
290 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
291 *********************************************************************/
292
293/**
294 * adjust_jiffies - adjust the system "loops_per_jiffy"
295 *
296 * This function alters the system "loops_per_jiffy" for the clock
297 * speed change. Note that loops_per_jiffy cannot be updated on SMP
298 * systems as each CPU might be scaled differently. So, use the arch
299 * per-CPU loops_per_jiffy value wherever possible.
300 */
301static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
302{
303#ifndef CONFIG_SMP
304 static unsigned long l_p_j_ref;
305 static unsigned int l_p_j_ref_freq;
306
307 if (ci->flags & CPUFREQ_CONST_LOOPS)
308 return;
309
310 if (!l_p_j_ref_freq) {
311 l_p_j_ref = loops_per_jiffy;
312 l_p_j_ref_freq = ci->old;
313 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
314 l_p_j_ref, l_p_j_ref_freq);
315 }
316 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
317 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
318 ci->new);
319 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
320 loops_per_jiffy, ci->new);
321 }
322#endif
323}
324
325/**
326 * cpufreq_notify_transition - Notify frequency transition and adjust_jiffies.
327 * @policy: cpufreq policy to enable fast frequency switching for.
328 * @freqs: contain details of the frequency update.
329 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.
330 *
331 * This function calls the transition notifiers and the "adjust_jiffies"
332 * function. It is called twice on all CPU frequency changes that have
333 * external effects.
334 */
335static void cpufreq_notify_transition(struct cpufreq_policy *policy,
336 struct cpufreq_freqs *freqs,
337 unsigned int state)
338{
339 int cpu;
340
341 BUG_ON(irqs_disabled());
342
343 if (cpufreq_disabled())
344 return;
345
346 freqs->policy = policy;
347 freqs->flags = cpufreq_driver->flags;
348 pr_debug("notification %u of frequency transition to %u kHz\n",
349 state, freqs->new);
350
351 switch (state) {
352 case CPUFREQ_PRECHANGE:
353 /*
354 * Detect if the driver reported a value as "old frequency"
355 * which is not equal to what the cpufreq core thinks is
356 * "old frequency".
357 */
358 if (policy->cur && policy->cur != freqs->old) {
359 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
360 freqs->old, policy->cur);
361 freqs->old = policy->cur;
362 }
363
364 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
365 CPUFREQ_PRECHANGE, freqs);
366
367 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
368 break;
369
370 case CPUFREQ_POSTCHANGE:
371 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
372 pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
373 cpumask_pr_args(policy->cpus));
374
375 for_each_cpu(cpu, policy->cpus)
376 trace_cpu_frequency(freqs->new, cpu);
377
378 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
379 CPUFREQ_POSTCHANGE, freqs);
380
381 cpufreq_stats_record_transition(policy, freqs->new);
382 policy->cur = freqs->new;
383 }
384}
385
386/* Do post notifications when there are chances that transition has failed */
387static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
388 struct cpufreq_freqs *freqs, int transition_failed)
389{
390 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
391 if (!transition_failed)
392 return;
393
394 swap(freqs->old, freqs->new);
395 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
396 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
397}
398
399void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
400 struct cpufreq_freqs *freqs)
401{
402
403 /*
404 * Catch double invocations of _begin() which lead to self-deadlock.
405 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
406 * doesn't invoke _begin() on their behalf, and hence the chances of
407 * double invocations are very low. Moreover, there are scenarios
408 * where these checks can emit false-positive warnings in these
409 * drivers; so we avoid that by skipping them altogether.
410 */
411 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
412 && current == policy->transition_task);
413
414wait:
415 wait_event(policy->transition_wait, !policy->transition_ongoing);
416
417 spin_lock(&policy->transition_lock);
418
419 if (unlikely(policy->transition_ongoing)) {
420 spin_unlock(&policy->transition_lock);
421 goto wait;
422 }
423
424 policy->transition_ongoing = true;
425 policy->transition_task = current;
426
427 spin_unlock(&policy->transition_lock);
428
429 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
430}
431EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
432
433void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
434 struct cpufreq_freqs *freqs, int transition_failed)
435{
436 if (WARN_ON(!policy->transition_ongoing))
437 return;
438
439 cpufreq_notify_post_transition(policy, freqs, transition_failed);
440
441 policy->transition_ongoing = false;
442 policy->transition_task = NULL;
443
444 wake_up(&policy->transition_wait);
445}
446EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
447
448/*
449 * Fast frequency switching status count. Positive means "enabled", negative
450 * means "disabled" and 0 means "not decided yet".
451 */
452static int cpufreq_fast_switch_count;
453static DEFINE_MUTEX(cpufreq_fast_switch_lock);
454
455static void cpufreq_list_transition_notifiers(void)
456{
457 struct notifier_block *nb;
458
459 pr_info("Registered transition notifiers:\n");
460
461 mutex_lock(&cpufreq_transition_notifier_list.mutex);
462
463 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
464 pr_info("%pS\n", nb->notifier_call);
465
466 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
467}
468
469/**
470 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
471 * @policy: cpufreq policy to enable fast frequency switching for.
472 *
473 * Try to enable fast frequency switching for @policy.
474 *
475 * The attempt will fail if there is at least one transition notifier registered
476 * at this point, as fast frequency switching is quite fundamentally at odds
477 * with transition notifiers. Thus if successful, it will make registration of
478 * transition notifiers fail going forward.
479 */
480void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
481{
482 lockdep_assert_held(&policy->rwsem);
483
484 if (!policy->fast_switch_possible)
485 return;
486
487 mutex_lock(&cpufreq_fast_switch_lock);
488 if (cpufreq_fast_switch_count >= 0) {
489 cpufreq_fast_switch_count++;
490 policy->fast_switch_enabled = true;
491 } else {
492 pr_warn("CPU%u: Fast frequency switching not enabled\n",
493 policy->cpu);
494 cpufreq_list_transition_notifiers();
495 }
496 mutex_unlock(&cpufreq_fast_switch_lock);
497}
498EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
499
500/**
501 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
502 * @policy: cpufreq policy to disable fast frequency switching for.
503 */
504void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
505{
506 mutex_lock(&cpufreq_fast_switch_lock);
507 if (policy->fast_switch_enabled) {
508 policy->fast_switch_enabled = false;
509 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
510 cpufreq_fast_switch_count--;
511 }
512 mutex_unlock(&cpufreq_fast_switch_lock);
513}
514EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
515
516/**
517 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
518 * one.
519 * @target_freq: target frequency to resolve.
520 *
521 * The target to driver frequency mapping is cached in the policy.
522 *
523 * Return: Lowest driver-supported frequency greater than or equal to the
524 * given target_freq, subject to policy (min/max) and driver limitations.
525 */
526unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
527 unsigned int target_freq)
528{
529 target_freq = clamp_val(target_freq, policy->min, policy->max);
530 policy->cached_target_freq = target_freq;
531
532 if (cpufreq_driver->target_index) {
533 int idx;
534
535 idx = cpufreq_frequency_table_target(policy, target_freq,
536 CPUFREQ_RELATION_L);
537 policy->cached_resolved_idx = idx;
538 return policy->freq_table[idx].frequency;
539 }
540
541 if (cpufreq_driver->resolve_freq)
542 return cpufreq_driver->resolve_freq(policy, target_freq);
543
544 return target_freq;
545}
546EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
547
548unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy)
549{
550 unsigned int latency;
551
552 if (policy->transition_delay_us)
553 return policy->transition_delay_us;
554
555 latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
556 if (latency) {
557 /*
558 * For platforms that can change the frequency very fast (< 10
559 * us), the above formula gives a decent transition delay. But
560 * for platforms where transition_latency is in milliseconds, it
561 * ends up giving unrealistic values.
562 *
563 * Cap the default transition delay to 10 ms, which seems to be
564 * a reasonable amount of time after which we should reevaluate
565 * the frequency.
566 */
567 return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000);
568 }
569
570 return LATENCY_MULTIPLIER;
571}
572EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
573
574/*********************************************************************
575 * SYSFS INTERFACE *
576 *********************************************************************/
577static ssize_t show_boost(struct kobject *kobj,
578 struct kobj_attribute *attr, char *buf)
579{
580 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
581}
582
583static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
584 const char *buf, size_t count)
585{
586 int ret, enable;
587
588 ret = sscanf(buf, "%d", &enable);
589 if (ret != 1 || enable < 0 || enable > 1)
590 return -EINVAL;
591
592 if (cpufreq_boost_trigger_state(enable)) {
593 pr_err("%s: Cannot %s BOOST!\n",
594 __func__, enable ? "enable" : "disable");
595 return -EINVAL;
596 }
597
598 pr_debug("%s: cpufreq BOOST %s\n",
599 __func__, enable ? "enabled" : "disabled");
600
601 return count;
602}
603define_one_global_rw(boost);
604
605static struct cpufreq_governor *find_governor(const char *str_governor)
606{
607 struct cpufreq_governor *t;
608
609 for_each_governor(t)
610 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
611 return t;
612
613 return NULL;
614}
615
616static int cpufreq_parse_policy(char *str_governor,
617 struct cpufreq_policy *policy)
618{
619 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
620 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
621 return 0;
622 }
623 if (!strncasecmp(str_governor, "powersave", CPUFREQ_NAME_LEN)) {
624 policy->policy = CPUFREQ_POLICY_POWERSAVE;
625 return 0;
626 }
627 return -EINVAL;
628}
629
630/**
631 * cpufreq_parse_governor - parse a governor string only for has_target()
632 */
633static int cpufreq_parse_governor(char *str_governor,
634 struct cpufreq_policy *policy)
635{
636 struct cpufreq_governor *t;
637
638 mutex_lock(&cpufreq_governor_mutex);
639
640 t = find_governor(str_governor);
641 if (!t) {
642 int ret;
643
644 mutex_unlock(&cpufreq_governor_mutex);
645
646 ret = request_module("cpufreq_%s", str_governor);
647 if (ret)
648 return -EINVAL;
649
650 mutex_lock(&cpufreq_governor_mutex);
651
652 t = find_governor(str_governor);
653 }
654 if (t && !try_module_get(t->owner))
655 t = NULL;
656
657 mutex_unlock(&cpufreq_governor_mutex);
658
659 if (t) {
660 policy->governor = t;
661 return 0;
662 }
663
664 return -EINVAL;
665}
666
667/**
668 * cpufreq_per_cpu_attr_read() / show_##file_name() -
669 * print out cpufreq information
670 *
671 * Write out information from cpufreq_driver->policy[cpu]; object must be
672 * "unsigned int".
673 */
674
675#define show_one(file_name, object) \
676static ssize_t show_##file_name \
677(struct cpufreq_policy *policy, char *buf) \
678{ \
679 return sprintf(buf, "%u\n", policy->object); \
680}
681
682show_one(cpuinfo_min_freq, cpuinfo.min_freq);
683show_one(cpuinfo_max_freq, cpuinfo.max_freq);
684show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
685show_one(scaling_min_freq, min);
686show_one(scaling_max_freq, max);
687
688__weak unsigned int arch_freq_get_on_cpu(int cpu)
689{
690 return 0;
691}
692
693static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
694{
695 ssize_t ret;
696 unsigned int freq;
697
698 freq = arch_freq_get_on_cpu(policy->cpu);
699 if (freq)
700 ret = sprintf(buf, "%u\n", freq);
701 else if (cpufreq_driver && cpufreq_driver->setpolicy &&
702 cpufreq_driver->get)
703 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
704 else
705 ret = sprintf(buf, "%u\n", policy->cur);
706 return ret;
707}
708
709/**
710 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
711 */
712#define store_one(file_name, object) \
713static ssize_t store_##file_name \
714(struct cpufreq_policy *policy, const char *buf, size_t count) \
715{ \
716 unsigned long val; \
717 int ret; \
718 \
719 ret = sscanf(buf, "%lu", &val); \
720 if (ret != 1) \
721 return -EINVAL; \
722 \
723 ret = freq_qos_update_request(policy->object##_freq_req, val);\
724 return ret >= 0 ? count : ret; \
725}
726
727store_one(scaling_min_freq, min);
728store_one(scaling_max_freq, max);
729
730/**
731 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
732 */
733static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
734 char *buf)
735{
736 unsigned int cur_freq = __cpufreq_get(policy);
737
738 if (cur_freq)
739 return sprintf(buf, "%u\n", cur_freq);
740
741 return sprintf(buf, "<unknown>\n");
742}
743
744/**
745 * show_scaling_governor - show the current policy for the specified CPU
746 */
747static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
748{
749 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
750 return sprintf(buf, "powersave\n");
751 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
752 return sprintf(buf, "performance\n");
753 else if (policy->governor)
754 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
755 policy->governor->name);
756 return -EINVAL;
757}
758
759/**
760 * store_scaling_governor - store policy for the specified CPU
761 */
762static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
763 const char *buf, size_t count)
764{
765 int ret;
766 char str_governor[16];
767 struct cpufreq_policy new_policy;
768
769 memcpy(&new_policy, policy, sizeof(*policy));
770
771 ret = sscanf(buf, "%15s", str_governor);
772 if (ret != 1)
773 return -EINVAL;
774
775 if (cpufreq_driver->setpolicy) {
776 if (cpufreq_parse_policy(str_governor, &new_policy))
777 return -EINVAL;
778 } else {
779 if (cpufreq_parse_governor(str_governor, &new_policy))
780 return -EINVAL;
781 }
782
783 ret = cpufreq_set_policy(policy, &new_policy);
784
785 if (new_policy.governor)
786 module_put(new_policy.governor->owner);
787
788 return ret ? ret : count;
789}
790
791/**
792 * show_scaling_driver - show the cpufreq driver currently loaded
793 */
794static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
795{
796 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
797}
798
799/**
800 * show_scaling_available_governors - show the available CPUfreq governors
801 */
802static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
803 char *buf)
804{
805 ssize_t i = 0;
806 struct cpufreq_governor *t;
807
808 if (!has_target()) {
809 i += sprintf(buf, "performance powersave");
810 goto out;
811 }
812
813 for_each_governor(t) {
814 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
815 - (CPUFREQ_NAME_LEN + 2)))
816 goto out;
817 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
818 }
819out:
820 i += sprintf(&buf[i], "\n");
821 return i;
822}
823
824ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
825{
826 ssize_t i = 0;
827 unsigned int cpu;
828
829 for_each_cpu(cpu, mask) {
830 if (i)
831 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
832 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
833 if (i >= (PAGE_SIZE - 5))
834 break;
835 }
836 i += sprintf(&buf[i], "\n");
837 return i;
838}
839EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
840
841/**
842 * show_related_cpus - show the CPUs affected by each transition even if
843 * hw coordination is in use
844 */
845static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
846{
847 return cpufreq_show_cpus(policy->related_cpus, buf);
848}
849
850/**
851 * show_affected_cpus - show the CPUs affected by each transition
852 */
853static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
854{
855 return cpufreq_show_cpus(policy->cpus, buf);
856}
857
858static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
859 const char *buf, size_t count)
860{
861 unsigned int freq = 0;
862 unsigned int ret;
863
864 if (!policy->governor || !policy->governor->store_setspeed)
865 return -EINVAL;
866
867 ret = sscanf(buf, "%u", &freq);
868 if (ret != 1)
869 return -EINVAL;
870
871 policy->governor->store_setspeed(policy, freq);
872
873 return count;
874}
875
876static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
877{
878 if (!policy->governor || !policy->governor->show_setspeed)
879 return sprintf(buf, "<unsupported>\n");
880
881 return policy->governor->show_setspeed(policy, buf);
882}
883
884/**
885 * show_bios_limit - show the current cpufreq HW/BIOS limitation
886 */
887static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
888{
889 unsigned int limit;
890 int ret;
891 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
892 if (!ret)
893 return sprintf(buf, "%u\n", limit);
894 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
895}
896
897cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
898cpufreq_freq_attr_ro(cpuinfo_min_freq);
899cpufreq_freq_attr_ro(cpuinfo_max_freq);
900cpufreq_freq_attr_ro(cpuinfo_transition_latency);
901cpufreq_freq_attr_ro(scaling_available_governors);
902cpufreq_freq_attr_ro(scaling_driver);
903cpufreq_freq_attr_ro(scaling_cur_freq);
904cpufreq_freq_attr_ro(bios_limit);
905cpufreq_freq_attr_ro(related_cpus);
906cpufreq_freq_attr_ro(affected_cpus);
907cpufreq_freq_attr_rw(scaling_min_freq);
908cpufreq_freq_attr_rw(scaling_max_freq);
909cpufreq_freq_attr_rw(scaling_governor);
910cpufreq_freq_attr_rw(scaling_setspeed);
911
912static struct attribute *default_attrs[] = {
913 &cpuinfo_min_freq.attr,
914 &cpuinfo_max_freq.attr,
915 &cpuinfo_transition_latency.attr,
916 &scaling_min_freq.attr,
917 &scaling_max_freq.attr,
918 &affected_cpus.attr,
919 &related_cpus.attr,
920 &scaling_governor.attr,
921 &scaling_driver.attr,
922 &scaling_available_governors.attr,
923 &scaling_setspeed.attr,
924 NULL
925};
926
927#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
928#define to_attr(a) container_of(a, struct freq_attr, attr)
929
930static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
931{
932 struct cpufreq_policy *policy = to_policy(kobj);
933 struct freq_attr *fattr = to_attr(attr);
934 ssize_t ret;
935
936 down_read(&policy->rwsem);
937 ret = fattr->show(policy, buf);
938 up_read(&policy->rwsem);
939
940 return ret;
941}
942
943static ssize_t store(struct kobject *kobj, struct attribute *attr,
944 const char *buf, size_t count)
945{
946 struct cpufreq_policy *policy = to_policy(kobj);
947 struct freq_attr *fattr = to_attr(attr);
948 ssize_t ret = -EINVAL;
949
950 /*
951 * cpus_read_trylock() is used here to work around a circular lock
952 * dependency problem with respect to the cpufreq_register_driver().
953 */
954 if (!cpus_read_trylock())
955 return -EBUSY;
956
957 if (cpu_online(policy->cpu)) {
958 down_write(&policy->rwsem);
959 ret = fattr->store(policy, buf, count);
960 up_write(&policy->rwsem);
961 }
962
963 cpus_read_unlock();
964
965 return ret;
966}
967
968static void cpufreq_sysfs_release(struct kobject *kobj)
969{
970 struct cpufreq_policy *policy = to_policy(kobj);
971 pr_debug("last reference is dropped\n");
972 complete(&policy->kobj_unregister);
973}
974
975static const struct sysfs_ops sysfs_ops = {
976 .show = show,
977 .store = store,
978};
979
980static struct kobj_type ktype_cpufreq = {
981 .sysfs_ops = &sysfs_ops,
982 .default_attrs = default_attrs,
983 .release = cpufreq_sysfs_release,
984};
985
986static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
987{
988 struct device *dev = get_cpu_device(cpu);
989
990 if (unlikely(!dev))
991 return;
992
993 if (cpumask_test_and_set_cpu(cpu, policy->real_cpus))
994 return;
995
996 dev_dbg(dev, "%s: Adding symlink\n", __func__);
997 if (sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"))
998 dev_err(dev, "cpufreq symlink creation failed\n");
999}
1000
1001static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
1002 struct device *dev)
1003{
1004 dev_dbg(dev, "%s: Removing symlink\n", __func__);
1005 sysfs_remove_link(&dev->kobj, "cpufreq");
1006}
1007
1008static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
1009{
1010 struct freq_attr **drv_attr;
1011 int ret = 0;
1012
1013 /* set up files for this cpu device */
1014 drv_attr = cpufreq_driver->attr;
1015 while (drv_attr && *drv_attr) {
1016 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
1017 if (ret)
1018 return ret;
1019 drv_attr++;
1020 }
1021 if (cpufreq_driver->get) {
1022 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
1023 if (ret)
1024 return ret;
1025 }
1026
1027 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
1028 if (ret)
1029 return ret;
1030
1031 if (cpufreq_driver->bios_limit) {
1032 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
1033 if (ret)
1034 return ret;
1035 }
1036
1037 return 0;
1038}
1039
1040__weak struct cpufreq_governor *cpufreq_default_governor(void)
1041{
1042 return NULL;
1043}
1044
1045static int cpufreq_init_policy(struct cpufreq_policy *policy)
1046{
1047 struct cpufreq_governor *gov = NULL, *def_gov = NULL;
1048 struct cpufreq_policy new_policy;
1049
1050 memcpy(&new_policy, policy, sizeof(*policy));
1051
1052 def_gov = cpufreq_default_governor();
1053
1054 if (has_target()) {
1055 /*
1056 * Update governor of new_policy to the governor used before
1057 * hotplug
1058 */
1059 gov = find_governor(policy->last_governor);
1060 if (gov) {
1061 pr_debug("Restoring governor %s for cpu %d\n",
1062 policy->governor->name, policy->cpu);
1063 } else {
1064 if (!def_gov)
1065 return -ENODATA;
1066 gov = def_gov;
1067 }
1068 new_policy.governor = gov;
1069 } else {
1070 /* Use the default policy if there is no last_policy. */
1071 if (policy->last_policy) {
1072 new_policy.policy = policy->last_policy;
1073 } else {
1074 if (!def_gov)
1075 return -ENODATA;
1076 cpufreq_parse_policy(def_gov->name, &new_policy);
1077 }
1078 }
1079
1080 return cpufreq_set_policy(policy, &new_policy);
1081}
1082
1083static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1084{
1085 int ret = 0;
1086
1087 /* Has this CPU been taken care of already? */
1088 if (cpumask_test_cpu(cpu, policy->cpus))
1089 return 0;
1090
1091 down_write(&policy->rwsem);
1092 if (has_target())
1093 cpufreq_stop_governor(policy);
1094
1095 cpumask_set_cpu(cpu, policy->cpus);
1096
1097 if (has_target()) {
1098 ret = cpufreq_start_governor(policy);
1099 if (ret)
1100 pr_err("%s: Failed to start governor\n", __func__);
1101 }
1102 up_write(&policy->rwsem);
1103 return ret;
1104}
1105
1106void refresh_frequency_limits(struct cpufreq_policy *policy)
1107{
1108 struct cpufreq_policy new_policy;
1109
1110 if (!policy_is_inactive(policy)) {
1111 new_policy = *policy;
1112 pr_debug("updating policy for CPU %u\n", policy->cpu);
1113
1114 cpufreq_set_policy(policy, &new_policy);
1115 }
1116}
1117EXPORT_SYMBOL(refresh_frequency_limits);
1118
1119static void handle_update(struct work_struct *work)
1120{
1121 struct cpufreq_policy *policy =
1122 container_of(work, struct cpufreq_policy, update);
1123
1124 pr_debug("handle_update for cpu %u called\n", policy->cpu);
1125 down_write(&policy->rwsem);
1126 refresh_frequency_limits(policy);
1127 up_write(&policy->rwsem);
1128}
1129
1130static int cpufreq_notifier_min(struct notifier_block *nb, unsigned long freq,
1131 void *data)
1132{
1133 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_min);
1134
1135 schedule_work(&policy->update);
1136 return 0;
1137}
1138
1139static int cpufreq_notifier_max(struct notifier_block *nb, unsigned long freq,
1140 void *data)
1141{
1142 struct cpufreq_policy *policy = container_of(nb, struct cpufreq_policy, nb_max);
1143
1144 schedule_work(&policy->update);
1145 return 0;
1146}
1147
1148static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1149{
1150 struct kobject *kobj;
1151 struct completion *cmp;
1152
1153 down_write(&policy->rwsem);
1154 cpufreq_stats_free_table(policy);
1155 kobj = &policy->kobj;
1156 cmp = &policy->kobj_unregister;
1157 up_write(&policy->rwsem);
1158 kobject_put(kobj);
1159
1160 /*
1161 * We need to make sure that the underlying kobj is
1162 * actually not referenced anymore by anybody before we
1163 * proceed with unloading.
1164 */
1165 pr_debug("waiting for dropping of refcount\n");
1166 wait_for_completion(cmp);
1167 pr_debug("wait complete\n");
1168}
1169
1170static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1171{
1172 struct cpufreq_policy *policy;
1173 struct device *dev = get_cpu_device(cpu);
1174 int ret;
1175
1176 if (!dev)
1177 return NULL;
1178
1179 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1180 if (!policy)
1181 return NULL;
1182
1183 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1184 goto err_free_policy;
1185
1186 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1187 goto err_free_cpumask;
1188
1189 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1190 goto err_free_rcpumask;
1191
1192 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1193 cpufreq_global_kobject, "policy%u", cpu);
1194 if (ret) {
1195 dev_err(dev, "%s: failed to init policy->kobj: %d\n", __func__, ret);
1196 /*
1197 * The entire policy object will be freed below, but the extra
1198 * memory allocated for the kobject name needs to be freed by
1199 * releasing the kobject.
1200 */
1201 kobject_put(&policy->kobj);
1202 goto err_free_real_cpus;
1203 }
1204
1205 freq_constraints_init(&policy->constraints);
1206
1207 policy->nb_min.notifier_call = cpufreq_notifier_min;
1208 policy->nb_max.notifier_call = cpufreq_notifier_max;
1209
1210 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MIN,
1211 &policy->nb_min);
1212 if (ret) {
1213 dev_err(dev, "Failed to register MIN QoS notifier: %d (%*pbl)\n",
1214 ret, cpumask_pr_args(policy->cpus));
1215 goto err_kobj_remove;
1216 }
1217
1218 ret = freq_qos_add_notifier(&policy->constraints, FREQ_QOS_MAX,
1219 &policy->nb_max);
1220 if (ret) {
1221 dev_err(dev, "Failed to register MAX QoS notifier: %d (%*pbl)\n",
1222 ret, cpumask_pr_args(policy->cpus));
1223 goto err_min_qos_notifier;
1224 }
1225
1226 INIT_LIST_HEAD(&policy->policy_list);
1227 init_rwsem(&policy->rwsem);
1228 spin_lock_init(&policy->transition_lock);
1229 init_waitqueue_head(&policy->transition_wait);
1230 init_completion(&policy->kobj_unregister);
1231 INIT_WORK(&policy->update, handle_update);
1232
1233 policy->cpu = cpu;
1234 return policy;
1235
1236err_min_qos_notifier:
1237 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1238 &policy->nb_min);
1239err_kobj_remove:
1240 cpufreq_policy_put_kobj(policy);
1241err_free_real_cpus:
1242 free_cpumask_var(policy->real_cpus);
1243err_free_rcpumask:
1244 free_cpumask_var(policy->related_cpus);
1245err_free_cpumask:
1246 free_cpumask_var(policy->cpus);
1247err_free_policy:
1248 kfree(policy);
1249
1250 return NULL;
1251}
1252
1253static void cpufreq_policy_free(struct cpufreq_policy *policy)
1254{
1255 unsigned long flags;
1256 int cpu;
1257
1258 /* Remove policy from list */
1259 write_lock_irqsave(&cpufreq_driver_lock, flags);
1260 list_del(&policy->policy_list);
1261
1262 for_each_cpu(cpu, policy->related_cpus)
1263 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1264 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1265
1266 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MAX,
1267 &policy->nb_max);
1268 freq_qos_remove_notifier(&policy->constraints, FREQ_QOS_MIN,
1269 &policy->nb_min);
1270
1271 /* Cancel any pending policy->update work before freeing the policy. */
1272 cancel_work_sync(&policy->update);
1273
1274 if (policy->max_freq_req) {
1275 /*
1276 * CPUFREQ_CREATE_POLICY notification is sent only after
1277 * successfully adding max_freq_req request.
1278 */
1279 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1280 CPUFREQ_REMOVE_POLICY, policy);
1281 freq_qos_remove_request(policy->max_freq_req);
1282 }
1283
1284 freq_qos_remove_request(policy->min_freq_req);
1285 kfree(policy->min_freq_req);
1286
1287 cpufreq_policy_put_kobj(policy);
1288 free_cpumask_var(policy->real_cpus);
1289 free_cpumask_var(policy->related_cpus);
1290 free_cpumask_var(policy->cpus);
1291 kfree(policy);
1292}
1293
1294static int cpufreq_online(unsigned int cpu)
1295{
1296 struct cpufreq_policy *policy;
1297 bool new_policy;
1298 unsigned long flags;
1299 unsigned int j;
1300 int ret;
1301
1302 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1303
1304 /* Check if this CPU already has a policy to manage it */
1305 policy = per_cpu(cpufreq_cpu_data, cpu);
1306 if (policy) {
1307 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1308 if (!policy_is_inactive(policy))
1309 return cpufreq_add_policy_cpu(policy, cpu);
1310
1311 /* This is the only online CPU for the policy. Start over. */
1312 new_policy = false;
1313 down_write(&policy->rwsem);
1314 policy->cpu = cpu;
1315 policy->governor = NULL;
1316 up_write(&policy->rwsem);
1317 } else {
1318 new_policy = true;
1319 policy = cpufreq_policy_alloc(cpu);
1320 if (!policy)
1321 return -ENOMEM;
1322 }
1323
1324 if (!new_policy && cpufreq_driver->online) {
1325 ret = cpufreq_driver->online(policy);
1326 if (ret) {
1327 pr_debug("%s: %d: initialization failed\n", __func__,
1328 __LINE__);
1329 goto out_exit_policy;
1330 }
1331
1332 /* Recover policy->cpus using related_cpus */
1333 cpumask_copy(policy->cpus, policy->related_cpus);
1334 } else {
1335 cpumask_copy(policy->cpus, cpumask_of(cpu));
1336
1337 /*
1338 * Call driver. From then on the cpufreq must be able
1339 * to accept all calls to ->verify and ->setpolicy for this CPU.
1340 */
1341 ret = cpufreq_driver->init(policy);
1342 if (ret) {
1343 pr_debug("%s: %d: initialization failed\n", __func__,
1344 __LINE__);
1345 goto out_free_policy;
1346 }
1347
1348 ret = cpufreq_table_validate_and_sort(policy);
1349 if (ret)
1350 goto out_exit_policy;
1351
1352 /* related_cpus should at least include policy->cpus. */
1353 cpumask_copy(policy->related_cpus, policy->cpus);
1354 }
1355
1356 down_write(&policy->rwsem);
1357 /*
1358 * affected cpus must always be the one, which are online. We aren't
1359 * managing offline cpus here.
1360 */
1361 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1362
1363 if (new_policy) {
1364 for_each_cpu(j, policy->related_cpus) {
1365 per_cpu(cpufreq_cpu_data, j) = policy;
1366 add_cpu_dev_symlink(policy, j);
1367 }
1368
1369 policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
1370 GFP_KERNEL);
1371 if (!policy->min_freq_req)
1372 goto out_destroy_policy;
1373
1374 ret = freq_qos_add_request(&policy->constraints,
1375 policy->min_freq_req, FREQ_QOS_MIN,
1376 policy->min);
1377 if (ret < 0) {
1378 /*
1379 * So we don't call freq_qos_remove_request() for an
1380 * uninitialized request.
1381 */
1382 kfree(policy->min_freq_req);
1383 policy->min_freq_req = NULL;
1384 goto out_destroy_policy;
1385 }
1386
1387 /*
1388 * This must be initialized right here to avoid calling
1389 * freq_qos_remove_request() on uninitialized request in case
1390 * of errors.
1391 */
1392 policy->max_freq_req = policy->min_freq_req + 1;
1393
1394 ret = freq_qos_add_request(&policy->constraints,
1395 policy->max_freq_req, FREQ_QOS_MAX,
1396 policy->max);
1397 if (ret < 0) {
1398 policy->max_freq_req = NULL;
1399 goto out_destroy_policy;
1400 }
1401
1402 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1403 CPUFREQ_CREATE_POLICY, policy);
1404 }
1405
1406 if (cpufreq_driver->get && has_target()) {
1407 policy->cur = cpufreq_driver->get(policy->cpu);
1408 if (!policy->cur) {
1409 pr_err("%s: ->get() failed\n", __func__);
1410 goto out_destroy_policy;
1411 }
1412 }
1413
1414 /*
1415 * Sometimes boot loaders set CPU frequency to a value outside of
1416 * frequency table present with cpufreq core. In such cases CPU might be
1417 * unstable if it has to run on that frequency for long duration of time
1418 * and so its better to set it to a frequency which is specified in
1419 * freq-table. This also makes cpufreq stats inconsistent as
1420 * cpufreq-stats would fail to register because current frequency of CPU
1421 * isn't found in freq-table.
1422 *
1423 * Because we don't want this change to effect boot process badly, we go
1424 * for the next freq which is >= policy->cur ('cur' must be set by now,
1425 * otherwise we will end up setting freq to lowest of the table as 'cur'
1426 * is initialized to zero).
1427 *
1428 * We are passing target-freq as "policy->cur - 1" otherwise
1429 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1430 * equal to target-freq.
1431 */
1432 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1433 && has_target()) {
1434 /* Are we running at unknown frequency ? */
1435 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1436 if (ret == -EINVAL) {
1437 /* Warn user and fix it */
1438 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1439 __func__, policy->cpu, policy->cur);
1440 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1441 CPUFREQ_RELATION_L);
1442
1443 /*
1444 * Reaching here after boot in a few seconds may not
1445 * mean that system will remain stable at "unknown"
1446 * frequency for longer duration. Hence, a BUG_ON().
1447 */
1448 BUG_ON(ret);
1449 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1450 __func__, policy->cpu, policy->cur);
1451 }
1452 }
1453
1454 if (new_policy) {
1455 ret = cpufreq_add_dev_interface(policy);
1456 if (ret)
1457 goto out_destroy_policy;
1458
1459 cpufreq_stats_create_table(policy);
1460
1461 write_lock_irqsave(&cpufreq_driver_lock, flags);
1462 list_add(&policy->policy_list, &cpufreq_policy_list);
1463 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1464 }
1465
1466 ret = cpufreq_init_policy(policy);
1467 if (ret) {
1468 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1469 __func__, cpu, ret);
1470 goto out_destroy_policy;
1471 }
1472
1473 up_write(&policy->rwsem);
1474
1475 kobject_uevent(&policy->kobj, KOBJ_ADD);
1476
1477 /* Callback for handling stuff after policy is ready */
1478 if (cpufreq_driver->ready)
1479 cpufreq_driver->ready(policy);
1480
1481 if (cpufreq_thermal_control_enabled(cpufreq_driver))
1482 policy->cdev = of_cpufreq_cooling_register(policy);
1483
1484 pr_debug("initialization complete\n");
1485
1486 return 0;
1487
1488out_destroy_policy:
1489 for_each_cpu(j, policy->real_cpus)
1490 remove_cpu_dev_symlink(policy, get_cpu_device(j));
1491
1492 up_write(&policy->rwsem);
1493
1494out_exit_policy:
1495 if (cpufreq_driver->exit)
1496 cpufreq_driver->exit(policy);
1497
1498out_free_policy:
1499 cpufreq_policy_free(policy);
1500 return ret;
1501}
1502
1503/**
1504 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1505 * @dev: CPU device.
1506 * @sif: Subsystem interface structure pointer (not used)
1507 */
1508static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1509{
1510 struct cpufreq_policy *policy;
1511 unsigned cpu = dev->id;
1512 int ret;
1513
1514 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1515
1516 if (cpu_online(cpu)) {
1517 ret = cpufreq_online(cpu);
1518 if (ret)
1519 return ret;
1520 }
1521
1522 /* Create sysfs link on CPU registration */
1523 policy = per_cpu(cpufreq_cpu_data, cpu);
1524 if (policy)
1525 add_cpu_dev_symlink(policy, cpu);
1526
1527 return 0;
1528}
1529
1530static int cpufreq_offline(unsigned int cpu)
1531{
1532 struct cpufreq_policy *policy;
1533 int ret;
1534
1535 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1536
1537 policy = cpufreq_cpu_get_raw(cpu);
1538 if (!policy) {
1539 pr_debug("%s: No cpu_data found\n", __func__);
1540 return 0;
1541 }
1542
1543 down_write(&policy->rwsem);
1544 if (has_target())
1545 cpufreq_stop_governor(policy);
1546
1547 cpumask_clear_cpu(cpu, policy->cpus);
1548
1549 if (policy_is_inactive(policy)) {
1550 if (has_target())
1551 strncpy(policy->last_governor, policy->governor->name,
1552 CPUFREQ_NAME_LEN);
1553 else
1554 policy->last_policy = policy->policy;
1555 } else if (cpu == policy->cpu) {
1556 /* Nominate new CPU */
1557 policy->cpu = cpumask_any(policy->cpus);
1558 }
1559
1560 /* Start governor again for active policy */
1561 if (!policy_is_inactive(policy)) {
1562 if (has_target()) {
1563 ret = cpufreq_start_governor(policy);
1564 if (ret)
1565 pr_err("%s: Failed to start governor\n", __func__);
1566 }
1567
1568 goto unlock;
1569 }
1570
1571 if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
1572 cpufreq_cooling_unregister(policy->cdev);
1573 policy->cdev = NULL;
1574 }
1575
1576 if (cpufreq_driver->stop_cpu)
1577 cpufreq_driver->stop_cpu(policy);
1578
1579 if (has_target())
1580 cpufreq_exit_governor(policy);
1581
1582 /*
1583 * Perform the ->offline() during light-weight tear-down, as
1584 * that allows fast recovery when the CPU comes back.
1585 */
1586 if (cpufreq_driver->offline) {
1587 cpufreq_driver->offline(policy);
1588 } else if (cpufreq_driver->exit) {
1589 cpufreq_driver->exit(policy);
1590 policy->freq_table = NULL;
1591 }
1592
1593unlock:
1594 up_write(&policy->rwsem);
1595 return 0;
1596}
1597
1598/**
1599 * cpufreq_remove_dev - remove a CPU device
1600 *
1601 * Removes the cpufreq interface for a CPU device.
1602 */
1603static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1604{
1605 unsigned int cpu = dev->id;
1606 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1607
1608 if (!policy)
1609 return;
1610
1611 if (cpu_online(cpu))
1612 cpufreq_offline(cpu);
1613
1614 cpumask_clear_cpu(cpu, policy->real_cpus);
1615 remove_cpu_dev_symlink(policy, dev);
1616
1617 if (cpumask_empty(policy->real_cpus)) {
1618 /* We did light-weight exit earlier, do full tear down now */
1619 if (cpufreq_driver->offline)
1620 cpufreq_driver->exit(policy);
1621
1622 cpufreq_policy_free(policy);
1623 }
1624}
1625
1626/**
1627 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1628 * in deep trouble.
1629 * @policy: policy managing CPUs
1630 * @new_freq: CPU frequency the CPU actually runs at
1631 *
1632 * We adjust to current frequency first, and need to clean up later.
1633 * So either call to cpufreq_update_policy() or schedule handle_update()).
1634 */
1635static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1636 unsigned int new_freq)
1637{
1638 struct cpufreq_freqs freqs;
1639
1640 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1641 policy->cur, new_freq);
1642
1643 freqs.old = policy->cur;
1644 freqs.new = new_freq;
1645
1646 cpufreq_freq_transition_begin(policy, &freqs);
1647 cpufreq_freq_transition_end(policy, &freqs, 0);
1648}
1649
1650static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, bool update)
1651{
1652 unsigned int new_freq;
1653
1654 new_freq = cpufreq_driver->get(policy->cpu);
1655 if (!new_freq)
1656 return 0;
1657
1658 /*
1659 * If fast frequency switching is used with the given policy, the check
1660 * against policy->cur is pointless, so skip it in that case.
1661 */
1662 if (policy->fast_switch_enabled || !has_target())
1663 return new_freq;
1664
1665 if (policy->cur != new_freq) {
1666 cpufreq_out_of_sync(policy, new_freq);
1667 if (update)
1668 schedule_work(&policy->update);
1669 }
1670
1671 return new_freq;
1672}
1673
1674/**
1675 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1676 * @cpu: CPU number
1677 *
1678 * This is the last known freq, without actually getting it from the driver.
1679 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1680 */
1681unsigned int cpufreq_quick_get(unsigned int cpu)
1682{
1683 struct cpufreq_policy *policy;
1684 unsigned int ret_freq = 0;
1685 unsigned long flags;
1686
1687 read_lock_irqsave(&cpufreq_driver_lock, flags);
1688
1689 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1690 ret_freq = cpufreq_driver->get(cpu);
1691 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1692 return ret_freq;
1693 }
1694
1695 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1696
1697 policy = cpufreq_cpu_get(cpu);
1698 if (policy) {
1699 ret_freq = policy->cur;
1700 cpufreq_cpu_put(policy);
1701 }
1702
1703 return ret_freq;
1704}
1705EXPORT_SYMBOL(cpufreq_quick_get);
1706
1707/**
1708 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1709 * @cpu: CPU number
1710 *
1711 * Just return the max possible frequency for a given CPU.
1712 */
1713unsigned int cpufreq_quick_get_max(unsigned int cpu)
1714{
1715 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1716 unsigned int ret_freq = 0;
1717
1718 if (policy) {
1719 ret_freq = policy->max;
1720 cpufreq_cpu_put(policy);
1721 }
1722
1723 return ret_freq;
1724}
1725EXPORT_SYMBOL(cpufreq_quick_get_max);
1726
1727static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1728{
1729 if (unlikely(policy_is_inactive(policy)))
1730 return 0;
1731
1732 return cpufreq_verify_current_freq(policy, true);
1733}
1734
1735/**
1736 * cpufreq_get - get the current CPU frequency (in kHz)
1737 * @cpu: CPU number
1738 *
1739 * Get the CPU current (static) CPU frequency
1740 */
1741unsigned int cpufreq_get(unsigned int cpu)
1742{
1743 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1744 unsigned int ret_freq = 0;
1745
1746 if (policy) {
1747 down_read(&policy->rwsem);
1748 if (cpufreq_driver->get)
1749 ret_freq = __cpufreq_get(policy);
1750 up_read(&policy->rwsem);
1751
1752 cpufreq_cpu_put(policy);
1753 }
1754
1755 return ret_freq;
1756}
1757EXPORT_SYMBOL(cpufreq_get);
1758
1759static struct subsys_interface cpufreq_interface = {
1760 .name = "cpufreq",
1761 .subsys = &cpu_subsys,
1762 .add_dev = cpufreq_add_dev,
1763 .remove_dev = cpufreq_remove_dev,
1764};
1765
1766/*
1767 * In case platform wants some specific frequency to be configured
1768 * during suspend..
1769 */
1770int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1771{
1772 int ret;
1773
1774 if (!policy->suspend_freq) {
1775 pr_debug("%s: suspend_freq not defined\n", __func__);
1776 return 0;
1777 }
1778
1779 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1780 policy->suspend_freq);
1781
1782 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1783 CPUFREQ_RELATION_H);
1784 if (ret)
1785 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1786 __func__, policy->suspend_freq, ret);
1787
1788 return ret;
1789}
1790EXPORT_SYMBOL(cpufreq_generic_suspend);
1791
1792/**
1793 * cpufreq_suspend() - Suspend CPUFreq governors
1794 *
1795 * Called during system wide Suspend/Hibernate cycles for suspending governors
1796 * as some platforms can't change frequency after this point in suspend cycle.
1797 * Because some of the devices (like: i2c, regulators, etc) they use for
1798 * changing frequency are suspended quickly after this point.
1799 */
1800void cpufreq_suspend(void)
1801{
1802 struct cpufreq_policy *policy;
1803
1804 if (!cpufreq_driver)
1805 return;
1806
1807 if (!has_target() && !cpufreq_driver->suspend)
1808 goto suspend;
1809
1810 pr_debug("%s: Suspending Governors\n", __func__);
1811
1812 for_each_active_policy(policy) {
1813 if (has_target()) {
1814 down_write(&policy->rwsem);
1815 cpufreq_stop_governor(policy);
1816 up_write(&policy->rwsem);
1817 }
1818
1819 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1820 pr_err("%s: Failed to suspend driver: %s\n", __func__,
1821 cpufreq_driver->name);
1822 }
1823
1824suspend:
1825 cpufreq_suspended = true;
1826}
1827
1828/**
1829 * cpufreq_resume() - Resume CPUFreq governors
1830 *
1831 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1832 * are suspended with cpufreq_suspend().
1833 */
1834void cpufreq_resume(void)
1835{
1836 struct cpufreq_policy *policy;
1837 int ret;
1838
1839 if (!cpufreq_driver)
1840 return;
1841
1842 if (unlikely(!cpufreq_suspended))
1843 return;
1844
1845 cpufreq_suspended = false;
1846
1847 if (!has_target() && !cpufreq_driver->resume)
1848 return;
1849
1850 pr_debug("%s: Resuming Governors\n", __func__);
1851
1852 for_each_active_policy(policy) {
1853 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1854 pr_err("%s: Failed to resume driver: %p\n", __func__,
1855 policy);
1856 } else if (has_target()) {
1857 down_write(&policy->rwsem);
1858 ret = cpufreq_start_governor(policy);
1859 up_write(&policy->rwsem);
1860
1861 if (ret)
1862 pr_err("%s: Failed to start governor for policy: %p\n",
1863 __func__, policy);
1864 }
1865 }
1866}
1867
1868/**
1869 * cpufreq_get_current_driver - return current driver's name
1870 *
1871 * Return the name string of the currently loaded cpufreq driver
1872 * or NULL, if none.
1873 */
1874const char *cpufreq_get_current_driver(void)
1875{
1876 if (cpufreq_driver)
1877 return cpufreq_driver->name;
1878
1879 return NULL;
1880}
1881EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1882
1883/**
1884 * cpufreq_get_driver_data - return current driver data
1885 *
1886 * Return the private data of the currently loaded cpufreq
1887 * driver, or NULL if no cpufreq driver is loaded.
1888 */
1889void *cpufreq_get_driver_data(void)
1890{
1891 if (cpufreq_driver)
1892 return cpufreq_driver->driver_data;
1893
1894 return NULL;
1895}
1896EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1897
1898/*********************************************************************
1899 * NOTIFIER LISTS INTERFACE *
1900 *********************************************************************/
1901
1902/**
1903 * cpufreq_register_notifier - register a driver with cpufreq
1904 * @nb: notifier function to register
1905 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1906 *
1907 * Add a driver to one of two lists: either a list of drivers that
1908 * are notified about clock rate changes (once before and once after
1909 * the transition), or a list of drivers that are notified about
1910 * changes in cpufreq policy.
1911 *
1912 * This function may sleep, and has the same return conditions as
1913 * blocking_notifier_chain_register.
1914 */
1915int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1916{
1917 int ret;
1918
1919 if (cpufreq_disabled())
1920 return -EINVAL;
1921
1922 switch (list) {
1923 case CPUFREQ_TRANSITION_NOTIFIER:
1924 mutex_lock(&cpufreq_fast_switch_lock);
1925
1926 if (cpufreq_fast_switch_count > 0) {
1927 mutex_unlock(&cpufreq_fast_switch_lock);
1928 return -EBUSY;
1929 }
1930 ret = srcu_notifier_chain_register(
1931 &cpufreq_transition_notifier_list, nb);
1932 if (!ret)
1933 cpufreq_fast_switch_count--;
1934
1935 mutex_unlock(&cpufreq_fast_switch_lock);
1936 break;
1937 case CPUFREQ_POLICY_NOTIFIER:
1938 ret = blocking_notifier_chain_register(
1939 &cpufreq_policy_notifier_list, nb);
1940 break;
1941 default:
1942 ret = -EINVAL;
1943 }
1944
1945 return ret;
1946}
1947EXPORT_SYMBOL(cpufreq_register_notifier);
1948
1949/**
1950 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1951 * @nb: notifier block to be unregistered
1952 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1953 *
1954 * Remove a driver from the CPU frequency notifier list.
1955 *
1956 * This function may sleep, and has the same return conditions as
1957 * blocking_notifier_chain_unregister.
1958 */
1959int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1960{
1961 int ret;
1962
1963 if (cpufreq_disabled())
1964 return -EINVAL;
1965
1966 switch (list) {
1967 case CPUFREQ_TRANSITION_NOTIFIER:
1968 mutex_lock(&cpufreq_fast_switch_lock);
1969
1970 ret = srcu_notifier_chain_unregister(
1971 &cpufreq_transition_notifier_list, nb);
1972 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1973 cpufreq_fast_switch_count++;
1974
1975 mutex_unlock(&cpufreq_fast_switch_lock);
1976 break;
1977 case CPUFREQ_POLICY_NOTIFIER:
1978 ret = blocking_notifier_chain_unregister(
1979 &cpufreq_policy_notifier_list, nb);
1980 break;
1981 default:
1982 ret = -EINVAL;
1983 }
1984
1985 return ret;
1986}
1987EXPORT_SYMBOL(cpufreq_unregister_notifier);
1988
1989
1990/*********************************************************************
1991 * GOVERNORS *
1992 *********************************************************************/
1993
1994/**
1995 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1996 * @policy: cpufreq policy to switch the frequency for.
1997 * @target_freq: New frequency to set (may be approximate).
1998 *
1999 * Carry out a fast frequency switch without sleeping.
2000 *
2001 * The driver's ->fast_switch() callback invoked by this function must be
2002 * suitable for being called from within RCU-sched read-side critical sections
2003 * and it is expected to select the minimum available frequency greater than or
2004 * equal to @target_freq (CPUFREQ_RELATION_L).
2005 *
2006 * This function must not be called if policy->fast_switch_enabled is unset.
2007 *
2008 * Governors calling this function must guarantee that it will never be invoked
2009 * twice in parallel for the same policy and that it will never be called in
2010 * parallel with either ->target() or ->target_index() for the same policy.
2011 *
2012 * Returns the actual frequency set for the CPU.
2013 *
2014 * If 0 is returned by the driver's ->fast_switch() callback to indicate an
2015 * error condition, the hardware configuration must be preserved.
2016 */
2017unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
2018 unsigned int target_freq)
2019{
2020 target_freq = clamp_val(target_freq, policy->min, policy->max);
2021
2022 return cpufreq_driver->fast_switch(policy, target_freq);
2023}
2024EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
2025
2026/* Must set freqs->new to intermediate frequency */
2027static int __target_intermediate(struct cpufreq_policy *policy,
2028 struct cpufreq_freqs *freqs, int index)
2029{
2030 int ret;
2031
2032 freqs->new = cpufreq_driver->get_intermediate(policy, index);
2033
2034 /* We don't need to switch to intermediate freq */
2035 if (!freqs->new)
2036 return 0;
2037
2038 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
2039 __func__, policy->cpu, freqs->old, freqs->new);
2040
2041 cpufreq_freq_transition_begin(policy, freqs);
2042 ret = cpufreq_driver->target_intermediate(policy, index);
2043 cpufreq_freq_transition_end(policy, freqs, ret);
2044
2045 if (ret)
2046 pr_err("%s: Failed to change to intermediate frequency: %d\n",
2047 __func__, ret);
2048
2049 return ret;
2050}
2051
2052static int __target_index(struct cpufreq_policy *policy, int index)
2053{
2054 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
2055 unsigned int intermediate_freq = 0;
2056 unsigned int newfreq = policy->freq_table[index].frequency;
2057 int retval = -EINVAL;
2058 bool notify;
2059
2060 if (newfreq == policy->cur)
2061 return 0;
2062
2063 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
2064 if (notify) {
2065 /* Handle switching to intermediate frequency */
2066 if (cpufreq_driver->get_intermediate) {
2067 retval = __target_intermediate(policy, &freqs, index);
2068 if (retval)
2069 return retval;
2070
2071 intermediate_freq = freqs.new;
2072 /* Set old freq to intermediate */
2073 if (intermediate_freq)
2074 freqs.old = freqs.new;
2075 }
2076
2077 freqs.new = newfreq;
2078 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
2079 __func__, policy->cpu, freqs.old, freqs.new);
2080
2081 cpufreq_freq_transition_begin(policy, &freqs);
2082 }
2083
2084 retval = cpufreq_driver->target_index(policy, index);
2085 if (retval)
2086 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
2087 retval);
2088
2089 if (notify) {
2090 cpufreq_freq_transition_end(policy, &freqs, retval);
2091
2092 /*
2093 * Failed after setting to intermediate freq? Driver should have
2094 * reverted back to initial frequency and so should we. Check
2095 * here for intermediate_freq instead of get_intermediate, in
2096 * case we haven't switched to intermediate freq at all.
2097 */
2098 if (unlikely(retval && intermediate_freq)) {
2099 freqs.old = intermediate_freq;
2100 freqs.new = policy->restore_freq;
2101 cpufreq_freq_transition_begin(policy, &freqs);
2102 cpufreq_freq_transition_end(policy, &freqs, 0);
2103 }
2104 }
2105
2106 return retval;
2107}
2108
2109int __cpufreq_driver_target(struct cpufreq_policy *policy,
2110 unsigned int target_freq,
2111 unsigned int relation)
2112{
2113 unsigned int old_target_freq = target_freq;
2114 int index;
2115
2116 if (cpufreq_disabled())
2117 return -ENODEV;
2118
2119 /* Make sure that target_freq is within supported range */
2120 target_freq = clamp_val(target_freq, policy->min, policy->max);
2121
2122 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
2123 policy->cpu, target_freq, relation, old_target_freq);
2124
2125 /*
2126 * This might look like a redundant call as we are checking it again
2127 * after finding index. But it is left intentionally for cases where
2128 * exactly same freq is called again and so we can save on few function
2129 * calls.
2130 */
2131 if (target_freq == policy->cur)
2132 return 0;
2133
2134 /* Save last value to restore later on errors */
2135 policy->restore_freq = policy->cur;
2136
2137 if (cpufreq_driver->target)
2138 return cpufreq_driver->target(policy, target_freq, relation);
2139
2140 if (!cpufreq_driver->target_index)
2141 return -EINVAL;
2142
2143 index = cpufreq_frequency_table_target(policy, target_freq, relation);
2144
2145 return __target_index(policy, index);
2146}
2147EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
2148
2149int cpufreq_driver_target(struct cpufreq_policy *policy,
2150 unsigned int target_freq,
2151 unsigned int relation)
2152{
2153 int ret;
2154
2155 down_write(&policy->rwsem);
2156
2157 ret = __cpufreq_driver_target(policy, target_freq, relation);
2158
2159 up_write(&policy->rwsem);
2160
2161 return ret;
2162}
2163EXPORT_SYMBOL_GPL(cpufreq_driver_target);
2164
2165__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
2166{
2167 return NULL;
2168}
2169
2170static int cpufreq_init_governor(struct cpufreq_policy *policy)
2171{
2172 int ret;
2173
2174 /* Don't start any governor operations if we are entering suspend */
2175 if (cpufreq_suspended)
2176 return 0;
2177 /*
2178 * Governor might not be initiated here if ACPI _PPC changed
2179 * notification happened, so check it.
2180 */
2181 if (!policy->governor)
2182 return -EINVAL;
2183
2184 /* Platform doesn't want dynamic frequency switching ? */
2185 if (policy->governor->dynamic_switching &&
2186 cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) {
2187 struct cpufreq_governor *gov = cpufreq_fallback_governor();
2188
2189 if (gov) {
2190 pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n",
2191 policy->governor->name, gov->name);
2192 policy->governor = gov;
2193 } else {
2194 return -EINVAL;
2195 }
2196 }
2197
2198 if (!try_module_get(policy->governor->owner))
2199 return -EINVAL;
2200
2201 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2202
2203 if (policy->governor->init) {
2204 ret = policy->governor->init(policy);
2205 if (ret) {
2206 module_put(policy->governor->owner);
2207 return ret;
2208 }
2209 }
2210
2211 return 0;
2212}
2213
2214static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2215{
2216 if (cpufreq_suspended || !policy->governor)
2217 return;
2218
2219 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2220
2221 if (policy->governor->exit)
2222 policy->governor->exit(policy);
2223
2224 module_put(policy->governor->owner);
2225}
2226
2227static int cpufreq_start_governor(struct cpufreq_policy *policy)
2228{
2229 int ret;
2230
2231 if (cpufreq_suspended)
2232 return 0;
2233
2234 if (!policy->governor)
2235 return -EINVAL;
2236
2237 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2238
2239 if (cpufreq_driver->get)
2240 cpufreq_verify_current_freq(policy, false);
2241
2242 if (policy->governor->start) {
2243 ret = policy->governor->start(policy);
2244 if (ret)
2245 return ret;
2246 }
2247
2248 if (policy->governor->limits)
2249 policy->governor->limits(policy);
2250
2251 return 0;
2252}
2253
2254static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2255{
2256 if (cpufreq_suspended || !policy->governor)
2257 return;
2258
2259 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2260
2261 if (policy->governor->stop)
2262 policy->governor->stop(policy);
2263}
2264
2265static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2266{
2267 if (cpufreq_suspended || !policy->governor)
2268 return;
2269
2270 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2271
2272 if (policy->governor->limits)
2273 policy->governor->limits(policy);
2274}
2275
2276int cpufreq_register_governor(struct cpufreq_governor *governor)
2277{
2278 int err;
2279
2280 if (!governor)
2281 return -EINVAL;
2282
2283 if (cpufreq_disabled())
2284 return -ENODEV;
2285
2286 mutex_lock(&cpufreq_governor_mutex);
2287
2288 err = -EBUSY;
2289 if (!find_governor(governor->name)) {
2290 err = 0;
2291 list_add(&governor->governor_list, &cpufreq_governor_list);
2292 }
2293
2294 mutex_unlock(&cpufreq_governor_mutex);
2295 return err;
2296}
2297EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2298
2299void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2300{
2301 struct cpufreq_policy *policy;
2302 unsigned long flags;
2303
2304 if (!governor)
2305 return;
2306
2307 if (cpufreq_disabled())
2308 return;
2309
2310 /* clear last_governor for all inactive policies */
2311 read_lock_irqsave(&cpufreq_driver_lock, flags);
2312 for_each_inactive_policy(policy) {
2313 if (!strcmp(policy->last_governor, governor->name)) {
2314 policy->governor = NULL;
2315 strcpy(policy->last_governor, "\0");
2316 }
2317 }
2318 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2319
2320 mutex_lock(&cpufreq_governor_mutex);
2321 list_del(&governor->governor_list);
2322 mutex_unlock(&cpufreq_governor_mutex);
2323}
2324EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2325
2326
2327/*********************************************************************
2328 * POLICY INTERFACE *
2329 *********************************************************************/
2330
2331/**
2332 * cpufreq_get_policy - get the current cpufreq_policy
2333 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2334 * is written
2335 *
2336 * Reads the current cpufreq policy.
2337 */
2338int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2339{
2340 struct cpufreq_policy *cpu_policy;
2341 if (!policy)
2342 return -EINVAL;
2343
2344 cpu_policy = cpufreq_cpu_get(cpu);
2345 if (!cpu_policy)
2346 return -EINVAL;
2347
2348 memcpy(policy, cpu_policy, sizeof(*policy));
2349
2350 cpufreq_cpu_put(cpu_policy);
2351 return 0;
2352}
2353EXPORT_SYMBOL(cpufreq_get_policy);
2354
2355/**
2356 * cpufreq_set_policy - Modify cpufreq policy parameters.
2357 * @policy: Policy object to modify.
2358 * @new_policy: New policy data.
2359 *
2360 * Pass @new_policy to the cpufreq driver's ->verify() callback. Next, copy the
2361 * min and max parameters of @new_policy to @policy and either invoke the
2362 * driver's ->setpolicy() callback (if present) or carry out a governor update
2363 * for @policy. That is, run the current governor's ->limits() callback (if the
2364 * governor field in @new_policy points to the same object as the one in
2365 * @policy) or replace the governor for @policy with the new one stored in
2366 * @new_policy.
2367 *
2368 * The cpuinfo part of @policy is not updated by this function.
2369 */
2370int cpufreq_set_policy(struct cpufreq_policy *policy,
2371 struct cpufreq_policy *new_policy)
2372{
2373 struct cpufreq_governor *old_gov;
2374 int ret;
2375
2376 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2377 new_policy->cpu, new_policy->min, new_policy->max);
2378
2379 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2380
2381 /*
2382 * PM QoS framework collects all the requests from users and provide us
2383 * the final aggregated value here.
2384 */
2385 new_policy->min = freq_qos_read_value(&policy->constraints, FREQ_QOS_MIN);
2386 new_policy->max = freq_qos_read_value(&policy->constraints, FREQ_QOS_MAX);
2387
2388 /* verify the cpu speed can be set within this limit */
2389 ret = cpufreq_driver->verify(new_policy);
2390 if (ret)
2391 return ret;
2392
2393 policy->min = new_policy->min;
2394 policy->max = new_policy->max;
2395 trace_cpu_frequency_limits(policy);
2396
2397 policy->cached_target_freq = UINT_MAX;
2398
2399 pr_debug("new min and max freqs are %u - %u kHz\n",
2400 policy->min, policy->max);
2401
2402 if (cpufreq_driver->setpolicy) {
2403 policy->policy = new_policy->policy;
2404 pr_debug("setting range\n");
2405 return cpufreq_driver->setpolicy(policy);
2406 }
2407
2408 if (new_policy->governor == policy->governor) {
2409 pr_debug("governor limits update\n");
2410 cpufreq_governor_limits(policy);
2411 return 0;
2412 }
2413
2414 pr_debug("governor switch\n");
2415
2416 /* save old, working values */
2417 old_gov = policy->governor;
2418 /* end old governor */
2419 if (old_gov) {
2420 cpufreq_stop_governor(policy);
2421 cpufreq_exit_governor(policy);
2422 }
2423
2424 /* start new governor */
2425 policy->governor = new_policy->governor;
2426 ret = cpufreq_init_governor(policy);
2427 if (!ret) {
2428 ret = cpufreq_start_governor(policy);
2429 if (!ret) {
2430 pr_debug("governor change\n");
2431 sched_cpufreq_governor_change(policy, old_gov);
2432 return 0;
2433 }
2434 cpufreq_exit_governor(policy);
2435 }
2436
2437 /* new governor failed, so re-start old one */
2438 pr_debug("starting governor %s failed\n", policy->governor->name);
2439 if (old_gov) {
2440 policy->governor = old_gov;
2441 if (cpufreq_init_governor(policy))
2442 policy->governor = NULL;
2443 else
2444 cpufreq_start_governor(policy);
2445 }
2446
2447 return ret;
2448}
2449
2450/**
2451 * cpufreq_update_policy - Re-evaluate an existing cpufreq policy.
2452 * @cpu: CPU to re-evaluate the policy for.
2453 *
2454 * Update the current frequency for the cpufreq policy of @cpu and use
2455 * cpufreq_set_policy() to re-apply the min and max limits, which triggers the
2456 * evaluation of policy notifiers and the cpufreq driver's ->verify() callback
2457 * for the policy in question, among other things.
2458 */
2459void cpufreq_update_policy(unsigned int cpu)
2460{
2461 struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
2462
2463 if (!policy)
2464 return;
2465
2466 /*
2467 * BIOS might change freq behind our back
2468 * -> ask driver for current freq and notify governors about a change
2469 */
2470 if (cpufreq_driver->get && has_target() &&
2471 (cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
2472 goto unlock;
2473
2474 refresh_frequency_limits(policy);
2475
2476unlock:
2477 cpufreq_cpu_release(policy);
2478}
2479EXPORT_SYMBOL(cpufreq_update_policy);
2480
2481/**
2482 * cpufreq_update_limits - Update policy limits for a given CPU.
2483 * @cpu: CPU to update the policy limits for.
2484 *
2485 * Invoke the driver's ->update_limits callback if present or call
2486 * cpufreq_update_policy() for @cpu.
2487 */
2488void cpufreq_update_limits(unsigned int cpu)
2489{
2490 if (cpufreq_driver->update_limits)
2491 cpufreq_driver->update_limits(cpu);
2492 else
2493 cpufreq_update_policy(cpu);
2494}
2495EXPORT_SYMBOL_GPL(cpufreq_update_limits);
2496
2497/*********************************************************************
2498 * BOOST *
2499 *********************************************************************/
2500static int cpufreq_boost_set_sw(int state)
2501{
2502 struct cpufreq_policy *policy;
2503 int ret = -EINVAL;
2504
2505 for_each_active_policy(policy) {
2506 if (!policy->freq_table)
2507 continue;
2508
2509 ret = cpufreq_frequency_table_cpuinfo(policy,
2510 policy->freq_table);
2511 if (ret) {
2512 pr_err("%s: Policy frequency update failed\n",
2513 __func__);
2514 break;
2515 }
2516
2517 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
2518 if (ret < 0)
2519 break;
2520 }
2521
2522 return ret;
2523}
2524
2525int cpufreq_boost_trigger_state(int state)
2526{
2527 unsigned long flags;
2528 int ret = 0;
2529
2530 if (cpufreq_driver->boost_enabled == state)
2531 return 0;
2532
2533 write_lock_irqsave(&cpufreq_driver_lock, flags);
2534 cpufreq_driver->boost_enabled = state;
2535 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2536
2537 ret = cpufreq_driver->set_boost(state);
2538 if (ret) {
2539 write_lock_irqsave(&cpufreq_driver_lock, flags);
2540 cpufreq_driver->boost_enabled = !state;
2541 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2542
2543 pr_err("%s: Cannot %s BOOST\n",
2544 __func__, state ? "enable" : "disable");
2545 }
2546
2547 return ret;
2548}
2549
2550static bool cpufreq_boost_supported(void)
2551{
2552 return cpufreq_driver->set_boost;
2553}
2554
2555static int create_boost_sysfs_file(void)
2556{
2557 int ret;
2558
2559 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2560 if (ret)
2561 pr_err("%s: cannot register global BOOST sysfs file\n",
2562 __func__);
2563
2564 return ret;
2565}
2566
2567static void remove_boost_sysfs_file(void)
2568{
2569 if (cpufreq_boost_supported())
2570 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2571}
2572
2573int cpufreq_enable_boost_support(void)
2574{
2575 if (!cpufreq_driver)
2576 return -EINVAL;
2577
2578 if (cpufreq_boost_supported())
2579 return 0;
2580
2581 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2582
2583 /* This will get removed on driver unregister */
2584 return create_boost_sysfs_file();
2585}
2586EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2587
2588int cpufreq_boost_enabled(void)
2589{
2590 return cpufreq_driver->boost_enabled;
2591}
2592EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2593
2594/*********************************************************************
2595 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2596 *********************************************************************/
2597static enum cpuhp_state hp_online;
2598
2599static int cpuhp_cpufreq_online(unsigned int cpu)
2600{
2601 cpufreq_online(cpu);
2602
2603 return 0;
2604}
2605
2606static int cpuhp_cpufreq_offline(unsigned int cpu)
2607{
2608 cpufreq_offline(cpu);
2609
2610 return 0;
2611}
2612
2613/**
2614 * cpufreq_register_driver - register a CPU Frequency driver
2615 * @driver_data: A struct cpufreq_driver containing the values#
2616 * submitted by the CPU Frequency driver.
2617 *
2618 * Registers a CPU Frequency driver to this core code. This code
2619 * returns zero on success, -EEXIST when another driver got here first
2620 * (and isn't unregistered in the meantime).
2621 *
2622 */
2623int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2624{
2625 unsigned long flags;
2626 int ret;
2627
2628 if (cpufreq_disabled())
2629 return -ENODEV;
2630
2631 if (!driver_data || !driver_data->verify || !driver_data->init ||
2632 !(driver_data->setpolicy || driver_data->target_index ||
2633 driver_data->target) ||
2634 (driver_data->setpolicy && (driver_data->target_index ||
2635 driver_data->target)) ||
2636 (!driver_data->get_intermediate != !driver_data->target_intermediate) ||
2637 (!driver_data->online != !driver_data->offline))
2638 return -EINVAL;
2639
2640 pr_debug("trying to register driver %s\n", driver_data->name);
2641
2642 /* Protect against concurrent CPU online/offline. */
2643 cpus_read_lock();
2644
2645 write_lock_irqsave(&cpufreq_driver_lock, flags);
2646 if (cpufreq_driver) {
2647 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2648 ret = -EEXIST;
2649 goto out;
2650 }
2651 cpufreq_driver = driver_data;
2652 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2653
2654 if (driver_data->setpolicy)
2655 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2656
2657 if (cpufreq_boost_supported()) {
2658 ret = create_boost_sysfs_file();
2659 if (ret)
2660 goto err_null_driver;
2661 }
2662
2663 ret = subsys_interface_register(&cpufreq_interface);
2664 if (ret)
2665 goto err_boost_unreg;
2666
2667 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2668 list_empty(&cpufreq_policy_list)) {
2669 /* if all ->init() calls failed, unregister */
2670 ret = -ENODEV;
2671 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2672 driver_data->name);
2673 goto err_if_unreg;
2674 }
2675
2676 ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
2677 "cpufreq:online",
2678 cpuhp_cpufreq_online,
2679 cpuhp_cpufreq_offline);
2680 if (ret < 0)
2681 goto err_if_unreg;
2682 hp_online = ret;
2683 ret = 0;
2684
2685 pr_debug("driver %s up and running\n", driver_data->name);
2686 goto out;
2687
2688err_if_unreg:
2689 subsys_interface_unregister(&cpufreq_interface);
2690err_boost_unreg:
2691 remove_boost_sysfs_file();
2692err_null_driver:
2693 write_lock_irqsave(&cpufreq_driver_lock, flags);
2694 cpufreq_driver = NULL;
2695 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2696out:
2697 cpus_read_unlock();
2698 return ret;
2699}
2700EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2701
2702/**
2703 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2704 *
2705 * Unregister the current CPUFreq driver. Only call this if you have
2706 * the right to do so, i.e. if you have succeeded in initialising before!
2707 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2708 * currently not initialised.
2709 */
2710int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2711{
2712 unsigned long flags;
2713
2714 if (!cpufreq_driver || (driver != cpufreq_driver))
2715 return -EINVAL;
2716
2717 pr_debug("unregistering driver %s\n", driver->name);
2718
2719 /* Protect against concurrent cpu hotplug */
2720 cpus_read_lock();
2721 subsys_interface_unregister(&cpufreq_interface);
2722 remove_boost_sysfs_file();
2723 cpuhp_remove_state_nocalls_cpuslocked(hp_online);
2724
2725 write_lock_irqsave(&cpufreq_driver_lock, flags);
2726
2727 cpufreq_driver = NULL;
2728
2729 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2730 cpus_read_unlock();
2731
2732 return 0;
2733}
2734EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2735
2736struct kobject *cpufreq_global_kobject;
2737EXPORT_SYMBOL(cpufreq_global_kobject);
2738
2739static int __init cpufreq_core_init(void)
2740{
2741 if (cpufreq_disabled())
2742 return -ENODEV;
2743
2744 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2745 BUG_ON(!cpufreq_global_kobject);
2746
2747 return 0;
2748}
2749module_param(off, int, 0444);
2750core_initcall(cpufreq_core_init);