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