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[linux-2.6-block.git] / drivers / cpufreq / cpufreq.c
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1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (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{
357
358 /*
359 * Catch double invocations of _begin() which lead to self-deadlock.
360 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
361 * doesn't invoke _begin() on their behalf, and hence the chances of
362 * double invocations are very low. Moreover, there are scenarios
363 * where these checks can emit false-positive warnings in these
364 * drivers; so we avoid that by skipping them altogether.
365 */
366 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
367 && current == policy->transition_task);
368
369wait:
370 wait_event(policy->transition_wait, !policy->transition_ongoing);
371
372 spin_lock(&policy->transition_lock);
373
374 if (unlikely(policy->transition_ongoing)) {
375 spin_unlock(&policy->transition_lock);
376 goto wait;
377 }
378
379 policy->transition_ongoing = true;
380 policy->transition_task = current;
381
382 spin_unlock(&policy->transition_lock);
383
384 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
385}
386EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
387
388void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
389 struct cpufreq_freqs *freqs, int transition_failed)
390{
391 if (unlikely(WARN_ON(!policy->transition_ongoing)))
392 return;
393
394 cpufreq_notify_post_transition(policy, freqs, transition_failed);
395
396 policy->transition_ongoing = false;
397 policy->transition_task = NULL;
398
399 wake_up(&policy->transition_wait);
400}
401EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
402
403
404/*********************************************************************
405 * SYSFS INTERFACE *
406 *********************************************************************/
407static ssize_t show_boost(struct kobject *kobj,
408 struct attribute *attr, char *buf)
409{
410 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
411}
412
413static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
414 const char *buf, size_t count)
415{
416 int ret, enable;
417
418 ret = sscanf(buf, "%d", &enable);
419 if (ret != 1 || enable < 0 || enable > 1)
420 return -EINVAL;
421
422 if (cpufreq_boost_trigger_state(enable)) {
423 pr_err("%s: Cannot %s BOOST!\n",
424 __func__, enable ? "enable" : "disable");
425 return -EINVAL;
426 }
427
428 pr_debug("%s: cpufreq BOOST %s\n",
429 __func__, enable ? "enabled" : "disabled");
430
431 return count;
432}
433define_one_global_rw(boost);
434
435static struct cpufreq_governor *__find_governor(const char *str_governor)
436{
437 struct cpufreq_governor *t;
438
439 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
440 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
441 return t;
442
443 return NULL;
444}
445
446/**
447 * cpufreq_parse_governor - parse a governor string
448 */
449static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
450 struct cpufreq_governor **governor)
451{
452 int err = -EINVAL;
453
454 if (!cpufreq_driver)
455 goto out;
456
457 if (cpufreq_driver->setpolicy) {
458 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
459 *policy = CPUFREQ_POLICY_PERFORMANCE;
460 err = 0;
461 } else if (!strnicmp(str_governor, "powersave",
462 CPUFREQ_NAME_LEN)) {
463 *policy = CPUFREQ_POLICY_POWERSAVE;
464 err = 0;
465 }
466 } else if (has_target()) {
467 struct cpufreq_governor *t;
468
469 mutex_lock(&cpufreq_governor_mutex);
470
471 t = __find_governor(str_governor);
472
473 if (t == NULL) {
474 int ret;
475
476 mutex_unlock(&cpufreq_governor_mutex);
477 ret = request_module("cpufreq_%s", str_governor);
478 mutex_lock(&cpufreq_governor_mutex);
479
480 if (ret == 0)
481 t = __find_governor(str_governor);
482 }
483
484 if (t != NULL) {
485 *governor = t;
486 err = 0;
487 }
488
489 mutex_unlock(&cpufreq_governor_mutex);
490 }
491out:
492 return err;
493}
494
495/**
496 * cpufreq_per_cpu_attr_read() / show_##file_name() -
497 * print out cpufreq information
498 *
499 * Write out information from cpufreq_driver->policy[cpu]; object must be
500 * "unsigned int".
501 */
502
503#define show_one(file_name, object) \
504static ssize_t show_##file_name \
505(struct cpufreq_policy *policy, char *buf) \
506{ \
507 return sprintf(buf, "%u\n", policy->object); \
508}
509
510show_one(cpuinfo_min_freq, cpuinfo.min_freq);
511show_one(cpuinfo_max_freq, cpuinfo.max_freq);
512show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
513show_one(scaling_min_freq, min);
514show_one(scaling_max_freq, max);
515show_one(scaling_cur_freq, cur);
516
517static int cpufreq_set_policy(struct cpufreq_policy *policy,
518 struct cpufreq_policy *new_policy);
519
520/**
521 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
522 */
523#define store_one(file_name, object) \
524static ssize_t store_##file_name \
525(struct cpufreq_policy *policy, const char *buf, size_t count) \
526{ \
527 int ret; \
528 struct cpufreq_policy new_policy; \
529 \
530 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
531 if (ret) \
532 return -EINVAL; \
533 \
534 ret = sscanf(buf, "%u", &new_policy.object); \
535 if (ret != 1) \
536 return -EINVAL; \
537 \
538 ret = cpufreq_set_policy(policy, &new_policy); \
539 policy->user_policy.object = policy->object; \
540 \
541 return ret ? ret : count; \
542}
543
544store_one(scaling_min_freq, min);
545store_one(scaling_max_freq, max);
546
547/**
548 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
549 */
550static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
551 char *buf)
552{
553 unsigned int cur_freq = __cpufreq_get(policy->cpu);
554 if (!cur_freq)
555 return sprintf(buf, "<unknown>");
556 return sprintf(buf, "%u\n", cur_freq);
557}
558
559/**
560 * show_scaling_governor - show the current policy for the specified CPU
561 */
562static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
563{
564 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
565 return sprintf(buf, "powersave\n");
566 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
567 return sprintf(buf, "performance\n");
568 else if (policy->governor)
569 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
570 policy->governor->name);
571 return -EINVAL;
572}
573
574/**
575 * store_scaling_governor - store policy for the specified CPU
576 */
577static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
578 const char *buf, size_t count)
579{
580 int ret;
581 char str_governor[16];
582 struct cpufreq_policy new_policy;
583
584 ret = cpufreq_get_policy(&new_policy, policy->cpu);
585 if (ret)
586 return ret;
587
588 ret = sscanf(buf, "%15s", str_governor);
589 if (ret != 1)
590 return -EINVAL;
591
592 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
593 &new_policy.governor))
594 return -EINVAL;
595
596 ret = cpufreq_set_policy(policy, &new_policy);
597
598 policy->user_policy.policy = policy->policy;
599 policy->user_policy.governor = policy->governor;
600
601 if (ret)
602 return ret;
603 else
604 return count;
605}
606
607/**
608 * show_scaling_driver - show the cpufreq driver currently loaded
609 */
610static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
611{
612 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
613}
614
615/**
616 * show_scaling_available_governors - show the available CPUfreq governors
617 */
618static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
619 char *buf)
620{
621 ssize_t i = 0;
622 struct cpufreq_governor *t;
623
624 if (!has_target()) {
625 i += sprintf(buf, "performance powersave");
626 goto out;
627 }
628
629 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
630 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
631 - (CPUFREQ_NAME_LEN + 2)))
632 goto out;
633 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
634 }
635out:
636 i += sprintf(&buf[i], "\n");
637 return i;
638}
639
640ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
641{
642 ssize_t i = 0;
643 unsigned int cpu;
644
645 for_each_cpu(cpu, mask) {
646 if (i)
647 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
648 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
649 if (i >= (PAGE_SIZE - 5))
650 break;
651 }
652 i += sprintf(&buf[i], "\n");
653 return i;
654}
655EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
656
657/**
658 * show_related_cpus - show the CPUs affected by each transition even if
659 * hw coordination is in use
660 */
661static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
662{
663 return cpufreq_show_cpus(policy->related_cpus, buf);
664}
665
666/**
667 * show_affected_cpus - show the CPUs affected by each transition
668 */
669static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
670{
671 return cpufreq_show_cpus(policy->cpus, buf);
672}
673
674static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
675 const char *buf, size_t count)
676{
677 unsigned int freq = 0;
678 unsigned int ret;
679
680 if (!policy->governor || !policy->governor->store_setspeed)
681 return -EINVAL;
682
683 ret = sscanf(buf, "%u", &freq);
684 if (ret != 1)
685 return -EINVAL;
686
687 policy->governor->store_setspeed(policy, freq);
688
689 return count;
690}
691
692static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
693{
694 if (!policy->governor || !policy->governor->show_setspeed)
695 return sprintf(buf, "<unsupported>\n");
696
697 return policy->governor->show_setspeed(policy, buf);
698}
699
700/**
701 * show_bios_limit - show the current cpufreq HW/BIOS limitation
702 */
703static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
704{
705 unsigned int limit;
706 int ret;
707 if (cpufreq_driver->bios_limit) {
708 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
709 if (!ret)
710 return sprintf(buf, "%u\n", limit);
711 }
712 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
713}
714
715cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
716cpufreq_freq_attr_ro(cpuinfo_min_freq);
717cpufreq_freq_attr_ro(cpuinfo_max_freq);
718cpufreq_freq_attr_ro(cpuinfo_transition_latency);
719cpufreq_freq_attr_ro(scaling_available_governors);
720cpufreq_freq_attr_ro(scaling_driver);
721cpufreq_freq_attr_ro(scaling_cur_freq);
722cpufreq_freq_attr_ro(bios_limit);
723cpufreq_freq_attr_ro(related_cpus);
724cpufreq_freq_attr_ro(affected_cpus);
725cpufreq_freq_attr_rw(scaling_min_freq);
726cpufreq_freq_attr_rw(scaling_max_freq);
727cpufreq_freq_attr_rw(scaling_governor);
728cpufreq_freq_attr_rw(scaling_setspeed);
729
730static struct attribute *default_attrs[] = {
731 &cpuinfo_min_freq.attr,
732 &cpuinfo_max_freq.attr,
733 &cpuinfo_transition_latency.attr,
734 &scaling_min_freq.attr,
735 &scaling_max_freq.attr,
736 &affected_cpus.attr,
737 &related_cpus.attr,
738 &scaling_governor.attr,
739 &scaling_driver.attr,
740 &scaling_available_governors.attr,
741 &scaling_setspeed.attr,
742 NULL
743};
744
745#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
746#define to_attr(a) container_of(a, struct freq_attr, attr)
747
748static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
749{
750 struct cpufreq_policy *policy = to_policy(kobj);
751 struct freq_attr *fattr = to_attr(attr);
752 ssize_t ret;
753
754 if (!down_read_trylock(&cpufreq_rwsem))
755 return -EINVAL;
756
757 down_read(&policy->rwsem);
758
759 if (fattr->show)
760 ret = fattr->show(policy, buf);
761 else
762 ret = -EIO;
763
764 up_read(&policy->rwsem);
765 up_read(&cpufreq_rwsem);
766
767 return ret;
768}
769
770static ssize_t store(struct kobject *kobj, struct attribute *attr,
771 const char *buf, size_t count)
772{
773 struct cpufreq_policy *policy = to_policy(kobj);
774 struct freq_attr *fattr = to_attr(attr);
775 ssize_t ret = -EINVAL;
776
777 get_online_cpus();
778
779 if (!cpu_online(policy->cpu))
780 goto unlock;
781
782 if (!down_read_trylock(&cpufreq_rwsem))
783 goto unlock;
784
785 down_write(&policy->rwsem);
786
787 if (fattr->store)
788 ret = fattr->store(policy, buf, count);
789 else
790 ret = -EIO;
791
792 up_write(&policy->rwsem);
793
794 up_read(&cpufreq_rwsem);
795unlock:
796 put_online_cpus();
797
798 return ret;
799}
800
801static void cpufreq_sysfs_release(struct kobject *kobj)
802{
803 struct cpufreq_policy *policy = to_policy(kobj);
804 pr_debug("last reference is dropped\n");
805 complete(&policy->kobj_unregister);
806}
807
808static const struct sysfs_ops sysfs_ops = {
809 .show = show,
810 .store = store,
811};
812
813static struct kobj_type ktype_cpufreq = {
814 .sysfs_ops = &sysfs_ops,
815 .default_attrs = default_attrs,
816 .release = cpufreq_sysfs_release,
817};
818
819struct kobject *cpufreq_global_kobject;
820EXPORT_SYMBOL(cpufreq_global_kobject);
821
822static int cpufreq_global_kobject_usage;
823
824int cpufreq_get_global_kobject(void)
825{
826 if (!cpufreq_global_kobject_usage++)
827 return kobject_add(cpufreq_global_kobject,
828 &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
829
830 return 0;
831}
832EXPORT_SYMBOL(cpufreq_get_global_kobject);
833
834void cpufreq_put_global_kobject(void)
835{
836 if (!--cpufreq_global_kobject_usage)
837 kobject_del(cpufreq_global_kobject);
838}
839EXPORT_SYMBOL(cpufreq_put_global_kobject);
840
841int cpufreq_sysfs_create_file(const struct attribute *attr)
842{
843 int ret = cpufreq_get_global_kobject();
844
845 if (!ret) {
846 ret = sysfs_create_file(cpufreq_global_kobject, attr);
847 if (ret)
848 cpufreq_put_global_kobject();
849 }
850
851 return ret;
852}
853EXPORT_SYMBOL(cpufreq_sysfs_create_file);
854
855void cpufreq_sysfs_remove_file(const struct attribute *attr)
856{
857 sysfs_remove_file(cpufreq_global_kobject, attr);
858 cpufreq_put_global_kobject();
859}
860EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
861
862/* symlink affected CPUs */
863static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
864{
865 unsigned int j;
866 int ret = 0;
867
868 for_each_cpu(j, policy->cpus) {
869 struct device *cpu_dev;
870
871 if (j == policy->cpu)
872 continue;
873
874 pr_debug("Adding link for CPU: %u\n", j);
875 cpu_dev = get_cpu_device(j);
876 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
877 "cpufreq");
878 if (ret)
879 break;
880 }
881 return ret;
882}
883
884static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
885 struct device *dev)
886{
887 struct freq_attr **drv_attr;
888 int ret = 0;
889
890 /* prepare interface data */
891 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
892 &dev->kobj, "cpufreq");
893 if (ret)
894 return ret;
895
896 /* set up files for this cpu device */
897 drv_attr = cpufreq_driver->attr;
898 while ((drv_attr) && (*drv_attr)) {
899 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
900 if (ret)
901 goto err_out_kobj_put;
902 drv_attr++;
903 }
904 if (cpufreq_driver->get) {
905 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
906 if (ret)
907 goto err_out_kobj_put;
908 }
909 if (has_target()) {
910 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
911 if (ret)
912 goto err_out_kobj_put;
913 }
914 if (cpufreq_driver->bios_limit) {
915 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
916 if (ret)
917 goto err_out_kobj_put;
918 }
919
920 ret = cpufreq_add_dev_symlink(policy);
921 if (ret)
922 goto err_out_kobj_put;
923
924 return ret;
925
926err_out_kobj_put:
927 kobject_put(&policy->kobj);
928 wait_for_completion(&policy->kobj_unregister);
929 return ret;
930}
931
932static void cpufreq_init_policy(struct cpufreq_policy *policy)
933{
934 struct cpufreq_governor *gov = NULL;
935 struct cpufreq_policy new_policy;
936 int ret = 0;
937
938 memcpy(&new_policy, policy, sizeof(*policy));
939
940 /* Update governor of new_policy to the governor used before hotplug */
941 gov = __find_governor(per_cpu(cpufreq_cpu_governor, policy->cpu));
942 if (gov)
943 pr_debug("Restoring governor %s for cpu %d\n",
944 policy->governor->name, policy->cpu);
945 else
946 gov = CPUFREQ_DEFAULT_GOVERNOR;
947
948 new_policy.governor = gov;
949
950 /* Use the default policy if its valid. */
951 if (cpufreq_driver->setpolicy)
952 cpufreq_parse_governor(gov->name, &new_policy.policy, NULL);
953
954 /* set default policy */
955 ret = cpufreq_set_policy(policy, &new_policy);
956 if (ret) {
957 pr_debug("setting policy failed\n");
958 if (cpufreq_driver->exit)
959 cpufreq_driver->exit(policy);
960 }
961}
962
963#ifdef CONFIG_HOTPLUG_CPU
964static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
965 unsigned int cpu, struct device *dev)
966{
967 int ret = 0;
968 unsigned long flags;
969
970 if (has_target()) {
971 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
972 if (ret) {
973 pr_err("%s: Failed to stop governor\n", __func__);
974 return ret;
975 }
976 }
977
978 down_write(&policy->rwsem);
979
980 write_lock_irqsave(&cpufreq_driver_lock, flags);
981
982 cpumask_set_cpu(cpu, policy->cpus);
983 per_cpu(cpufreq_cpu_data, cpu) = policy;
984 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
985
986 up_write(&policy->rwsem);
987
988 if (has_target()) {
989 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
990 if (!ret)
991 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
992
993 if (ret) {
994 pr_err("%s: Failed to start governor\n", __func__);
995 return ret;
996 }
997 }
998
999 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
1000}
1001#endif
1002
1003static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
1004{
1005 struct cpufreq_policy *policy;
1006 unsigned long flags;
1007
1008 read_lock_irqsave(&cpufreq_driver_lock, flags);
1009
1010 policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
1011
1012 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1013
1014 policy->governor = NULL;
1015
1016 return policy;
1017}
1018
1019static struct cpufreq_policy *cpufreq_policy_alloc(void)
1020{
1021 struct cpufreq_policy *policy;
1022
1023 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1024 if (!policy)
1025 return NULL;
1026
1027 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1028 goto err_free_policy;
1029
1030 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1031 goto err_free_cpumask;
1032
1033 INIT_LIST_HEAD(&policy->policy_list);
1034 init_rwsem(&policy->rwsem);
1035 spin_lock_init(&policy->transition_lock);
1036 init_waitqueue_head(&policy->transition_wait);
1037
1038 return policy;
1039
1040err_free_cpumask:
1041 free_cpumask_var(policy->cpus);
1042err_free_policy:
1043 kfree(policy);
1044
1045 return NULL;
1046}
1047
1048static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy)
1049{
1050 struct kobject *kobj;
1051 struct completion *cmp;
1052
1053 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1054 CPUFREQ_REMOVE_POLICY, policy);
1055
1056 down_read(&policy->rwsem);
1057 kobj = &policy->kobj;
1058 cmp = &policy->kobj_unregister;
1059 up_read(&policy->rwsem);
1060 kobject_put(kobj);
1061
1062 /*
1063 * We need to make sure that the underlying kobj is
1064 * actually not referenced anymore by anybody before we
1065 * proceed with unloading.
1066 */
1067 pr_debug("waiting for dropping of refcount\n");
1068 wait_for_completion(cmp);
1069 pr_debug("wait complete\n");
1070}
1071
1072static void cpufreq_policy_free(struct cpufreq_policy *policy)
1073{
1074 free_cpumask_var(policy->related_cpus);
1075 free_cpumask_var(policy->cpus);
1076 kfree(policy);
1077}
1078
1079static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1080{
1081 if (WARN_ON(cpu == policy->cpu))
1082 return;
1083
1084 down_write(&policy->rwsem);
1085
1086 policy->last_cpu = policy->cpu;
1087 policy->cpu = cpu;
1088
1089 up_write(&policy->rwsem);
1090
1091 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1092 CPUFREQ_UPDATE_POLICY_CPU, policy);
1093}
1094
1095static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1096{
1097 unsigned int j, cpu = dev->id;
1098 int ret = -ENOMEM;
1099 struct cpufreq_policy *policy;
1100 unsigned long flags;
1101 bool recover_policy = cpufreq_suspended;
1102#ifdef CONFIG_HOTPLUG_CPU
1103 struct cpufreq_policy *tpolicy;
1104#endif
1105
1106 if (cpu_is_offline(cpu))
1107 return 0;
1108
1109 pr_debug("adding CPU %u\n", cpu);
1110
1111#ifdef CONFIG_SMP
1112 /* check whether a different CPU already registered this
1113 * CPU because it is in the same boat. */
1114 policy = cpufreq_cpu_get(cpu);
1115 if (unlikely(policy)) {
1116 cpufreq_cpu_put(policy);
1117 return 0;
1118 }
1119#endif
1120
1121 if (!down_read_trylock(&cpufreq_rwsem))
1122 return 0;
1123
1124#ifdef CONFIG_HOTPLUG_CPU
1125 /* Check if this cpu was hot-unplugged earlier and has siblings */
1126 read_lock_irqsave(&cpufreq_driver_lock, flags);
1127 list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
1128 if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
1129 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1130 ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
1131 up_read(&cpufreq_rwsem);
1132 return ret;
1133 }
1134 }
1135 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1136#endif
1137
1138 /*
1139 * Restore the saved policy when doing light-weight init and fall back
1140 * to the full init if that fails.
1141 */
1142 policy = recover_policy ? cpufreq_policy_restore(cpu) : NULL;
1143 if (!policy) {
1144 recover_policy = false;
1145 policy = cpufreq_policy_alloc();
1146 if (!policy)
1147 goto nomem_out;
1148 }
1149
1150 /*
1151 * In the resume path, since we restore a saved policy, the assignment
1152 * to policy->cpu is like an update of the existing policy, rather than
1153 * the creation of a brand new one. So we need to perform this update
1154 * by invoking update_policy_cpu().
1155 */
1156 if (recover_policy && cpu != policy->cpu) {
1157 update_policy_cpu(policy, cpu);
1158 WARN_ON(kobject_move(&policy->kobj, &dev->kobj));
1159 } else {
1160 policy->cpu = cpu;
1161 }
1162
1163 cpumask_copy(policy->cpus, cpumask_of(cpu));
1164
1165 init_completion(&policy->kobj_unregister);
1166 INIT_WORK(&policy->update, handle_update);
1167
1168 /* call driver. From then on the cpufreq must be able
1169 * to accept all calls to ->verify and ->setpolicy for this CPU
1170 */
1171 ret = cpufreq_driver->init(policy);
1172 if (ret) {
1173 pr_debug("initialization failed\n");
1174 goto err_set_policy_cpu;
1175 }
1176
1177 /* related cpus should atleast have policy->cpus */
1178 cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
1179
1180 /*
1181 * affected cpus must always be the one, which are online. We aren't
1182 * managing offline cpus here.
1183 */
1184 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1185
1186 if (!recover_policy) {
1187 policy->user_policy.min = policy->min;
1188 policy->user_policy.max = policy->max;
1189 }
1190
1191 down_write(&policy->rwsem);
1192 write_lock_irqsave(&cpufreq_driver_lock, flags);
1193 for_each_cpu(j, policy->cpus)
1194 per_cpu(cpufreq_cpu_data, j) = policy;
1195 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1196
1197 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1198 policy->cur = cpufreq_driver->get(policy->cpu);
1199 if (!policy->cur) {
1200 pr_err("%s: ->get() failed\n", __func__);
1201 goto err_get_freq;
1202 }
1203 }
1204
1205 /*
1206 * Sometimes boot loaders set CPU frequency to a value outside of
1207 * frequency table present with cpufreq core. In such cases CPU might be
1208 * unstable if it has to run on that frequency for long duration of time
1209 * and so its better to set it to a frequency which is specified in
1210 * freq-table. This also makes cpufreq stats inconsistent as
1211 * cpufreq-stats would fail to register because current frequency of CPU
1212 * isn't found in freq-table.
1213 *
1214 * Because we don't want this change to effect boot process badly, we go
1215 * for the next freq which is >= policy->cur ('cur' must be set by now,
1216 * otherwise we will end up setting freq to lowest of the table as 'cur'
1217 * is initialized to zero).
1218 *
1219 * We are passing target-freq as "policy->cur - 1" otherwise
1220 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1221 * equal to target-freq.
1222 */
1223 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1224 && has_target()) {
1225 /* Are we running at unknown frequency ? */
1226 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1227 if (ret == -EINVAL) {
1228 /* Warn user and fix it */
1229 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1230 __func__, policy->cpu, policy->cur);
1231 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1232 CPUFREQ_RELATION_L);
1233
1234 /*
1235 * Reaching here after boot in a few seconds may not
1236 * mean that system will remain stable at "unknown"
1237 * frequency for longer duration. Hence, a BUG_ON().
1238 */
1239 BUG_ON(ret);
1240 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1241 __func__, policy->cpu, policy->cur);
1242 }
1243 }
1244
1245 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1246 CPUFREQ_START, policy);
1247
1248 if (!recover_policy) {
1249 ret = cpufreq_add_dev_interface(policy, dev);
1250 if (ret)
1251 goto err_out_unregister;
1252 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1253 CPUFREQ_CREATE_POLICY, policy);
1254 }
1255
1256 write_lock_irqsave(&cpufreq_driver_lock, flags);
1257 list_add(&policy->policy_list, &cpufreq_policy_list);
1258 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1259
1260 cpufreq_init_policy(policy);
1261
1262 if (!recover_policy) {
1263 policy->user_policy.policy = policy->policy;
1264 policy->user_policy.governor = policy->governor;
1265 }
1266 up_write(&policy->rwsem);
1267
1268 kobject_uevent(&policy->kobj, KOBJ_ADD);
1269 up_read(&cpufreq_rwsem);
1270
1271 pr_debug("initialization complete\n");
1272
1273 return 0;
1274
1275err_out_unregister:
1276err_get_freq:
1277 write_lock_irqsave(&cpufreq_driver_lock, flags);
1278 for_each_cpu(j, policy->cpus)
1279 per_cpu(cpufreq_cpu_data, j) = NULL;
1280 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1281
1282 if (cpufreq_driver->exit)
1283 cpufreq_driver->exit(policy);
1284err_set_policy_cpu:
1285 if (recover_policy) {
1286 /* Do not leave stale fallback data behind. */
1287 per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
1288 cpufreq_policy_put_kobj(policy);
1289 }
1290 cpufreq_policy_free(policy);
1291
1292nomem_out:
1293 up_read(&cpufreq_rwsem);
1294
1295 return ret;
1296}
1297
1298/**
1299 * cpufreq_add_dev - add a CPU device
1300 *
1301 * Adds the cpufreq interface for a CPU device.
1302 *
1303 * The Oracle says: try running cpufreq registration/unregistration concurrently
1304 * with with cpu hotplugging and all hell will break loose. Tried to clean this
1305 * mess up, but more thorough testing is needed. - Mathieu
1306 */
1307static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1308{
1309 return __cpufreq_add_dev(dev, sif);
1310}
1311
1312static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
1313 unsigned int old_cpu)
1314{
1315 struct device *cpu_dev;
1316 int ret;
1317
1318 /* first sibling now owns the new sysfs dir */
1319 cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
1320
1321 sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
1322 ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
1323 if (ret) {
1324 pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
1325
1326 down_write(&policy->rwsem);
1327 cpumask_set_cpu(old_cpu, policy->cpus);
1328 up_write(&policy->rwsem);
1329
1330 ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
1331 "cpufreq");
1332
1333 return -EINVAL;
1334 }
1335
1336 return cpu_dev->id;
1337}
1338
1339static int __cpufreq_remove_dev_prepare(struct device *dev,
1340 struct subsys_interface *sif)
1341{
1342 unsigned int cpu = dev->id, cpus;
1343 int new_cpu, ret;
1344 unsigned long flags;
1345 struct cpufreq_policy *policy;
1346
1347 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1348
1349 write_lock_irqsave(&cpufreq_driver_lock, flags);
1350
1351 policy = per_cpu(cpufreq_cpu_data, cpu);
1352
1353 /* Save the policy somewhere when doing a light-weight tear-down */
1354 if (cpufreq_suspended)
1355 per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
1356
1357 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1358
1359 if (!policy) {
1360 pr_debug("%s: No cpu_data found\n", __func__);
1361 return -EINVAL;
1362 }
1363
1364 if (has_target()) {
1365 ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
1366 if (ret) {
1367 pr_err("%s: Failed to stop governor\n", __func__);
1368 return ret;
1369 }
1370 }
1371
1372 if (!cpufreq_driver->setpolicy)
1373 strncpy(per_cpu(cpufreq_cpu_governor, cpu),
1374 policy->governor->name, CPUFREQ_NAME_LEN);
1375
1376 down_read(&policy->rwsem);
1377 cpus = cpumask_weight(policy->cpus);
1378 up_read(&policy->rwsem);
1379
1380 if (cpu != policy->cpu) {
1381 sysfs_remove_link(&dev->kobj, "cpufreq");
1382 } else if (cpus > 1) {
1383 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
1384 if (new_cpu >= 0) {
1385 update_policy_cpu(policy, new_cpu);
1386
1387 if (!cpufreq_suspended)
1388 pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
1389 __func__, new_cpu, cpu);
1390 }
1391 } else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
1392 cpufreq_driver->stop_cpu(policy);
1393 }
1394
1395 return 0;
1396}
1397
1398static int __cpufreq_remove_dev_finish(struct device *dev,
1399 struct subsys_interface *sif)
1400{
1401 unsigned int cpu = dev->id, cpus;
1402 int ret;
1403 unsigned long flags;
1404 struct cpufreq_policy *policy;
1405
1406 read_lock_irqsave(&cpufreq_driver_lock, flags);
1407 policy = per_cpu(cpufreq_cpu_data, cpu);
1408 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1409
1410 if (!policy) {
1411 pr_debug("%s: No cpu_data found\n", __func__);
1412 return -EINVAL;
1413 }
1414
1415 down_write(&policy->rwsem);
1416 cpus = cpumask_weight(policy->cpus);
1417
1418 if (cpus > 1)
1419 cpumask_clear_cpu(cpu, policy->cpus);
1420 up_write(&policy->rwsem);
1421
1422 /* If cpu is last user of policy, free policy */
1423 if (cpus == 1) {
1424 if (has_target()) {
1425 ret = __cpufreq_governor(policy,
1426 CPUFREQ_GOV_POLICY_EXIT);
1427 if (ret) {
1428 pr_err("%s: Failed to exit governor\n",
1429 __func__);
1430 return ret;
1431 }
1432 }
1433
1434 if (!cpufreq_suspended)
1435 cpufreq_policy_put_kobj(policy);
1436
1437 /*
1438 * Perform the ->exit() even during light-weight tear-down,
1439 * since this is a core component, and is essential for the
1440 * subsequent light-weight ->init() to succeed.
1441 */
1442 if (cpufreq_driver->exit)
1443 cpufreq_driver->exit(policy);
1444
1445 /* Remove policy from list of active policies */
1446 write_lock_irqsave(&cpufreq_driver_lock, flags);
1447 list_del(&policy->policy_list);
1448 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1449
1450 if (!cpufreq_suspended)
1451 cpufreq_policy_free(policy);
1452 } else if (has_target()) {
1453 ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);
1454 if (!ret)
1455 ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
1456
1457 if (ret) {
1458 pr_err("%s: Failed to start governor\n", __func__);
1459 return ret;
1460 }
1461 }
1462
1463 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1464 return 0;
1465}
1466
1467/**
1468 * cpufreq_remove_dev - remove a CPU device
1469 *
1470 * Removes the cpufreq interface for a CPU device.
1471 */
1472static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1473{
1474 unsigned int cpu = dev->id;
1475 int ret;
1476
1477 if (cpu_is_offline(cpu))
1478 return 0;
1479
1480 ret = __cpufreq_remove_dev_prepare(dev, sif);
1481
1482 if (!ret)
1483 ret = __cpufreq_remove_dev_finish(dev, sif);
1484
1485 return ret;
1486}
1487
1488static void handle_update(struct work_struct *work)
1489{
1490 struct cpufreq_policy *policy =
1491 container_of(work, struct cpufreq_policy, update);
1492 unsigned int cpu = policy->cpu;
1493 pr_debug("handle_update for cpu %u called\n", cpu);
1494 cpufreq_update_policy(cpu);
1495}
1496
1497/**
1498 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1499 * in deep trouble.
1500 * @cpu: cpu number
1501 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1502 * @new_freq: CPU frequency the CPU actually runs at
1503 *
1504 * We adjust to current frequency first, and need to clean up later.
1505 * So either call to cpufreq_update_policy() or schedule handle_update()).
1506 */
1507static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1508 unsigned int new_freq)
1509{
1510 struct cpufreq_policy *policy;
1511 struct cpufreq_freqs freqs;
1512 unsigned long flags;
1513
1514 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1515 old_freq, new_freq);
1516
1517 freqs.old = old_freq;
1518 freqs.new = new_freq;
1519
1520 read_lock_irqsave(&cpufreq_driver_lock, flags);
1521 policy = per_cpu(cpufreq_cpu_data, cpu);
1522 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1523
1524 cpufreq_freq_transition_begin(policy, &freqs);
1525 cpufreq_freq_transition_end(policy, &freqs, 0);
1526}
1527
1528/**
1529 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1530 * @cpu: CPU number
1531 *
1532 * This is the last known freq, without actually getting it from the driver.
1533 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1534 */
1535unsigned int cpufreq_quick_get(unsigned int cpu)
1536{
1537 struct cpufreq_policy *policy;
1538 unsigned int ret_freq = 0;
1539
1540 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
1541 return cpufreq_driver->get(cpu);
1542
1543 policy = cpufreq_cpu_get(cpu);
1544 if (policy) {
1545 ret_freq = policy->cur;
1546 cpufreq_cpu_put(policy);
1547 }
1548
1549 return ret_freq;
1550}
1551EXPORT_SYMBOL(cpufreq_quick_get);
1552
1553/**
1554 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1555 * @cpu: CPU number
1556 *
1557 * Just return the max possible frequency for a given CPU.
1558 */
1559unsigned int cpufreq_quick_get_max(unsigned int cpu)
1560{
1561 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1562 unsigned int ret_freq = 0;
1563
1564 if (policy) {
1565 ret_freq = policy->max;
1566 cpufreq_cpu_put(policy);
1567 }
1568
1569 return ret_freq;
1570}
1571EXPORT_SYMBOL(cpufreq_quick_get_max);
1572
1573static unsigned int __cpufreq_get(unsigned int cpu)
1574{
1575 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1576 unsigned int ret_freq = 0;
1577
1578 if (!cpufreq_driver->get)
1579 return ret_freq;
1580
1581 ret_freq = cpufreq_driver->get(cpu);
1582
1583 if (ret_freq && policy->cur &&
1584 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1585 /* verify no discrepancy between actual and
1586 saved value exists */
1587 if (unlikely(ret_freq != policy->cur)) {
1588 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1589 schedule_work(&policy->update);
1590 }
1591 }
1592
1593 return ret_freq;
1594}
1595
1596/**
1597 * cpufreq_get - get the current CPU frequency (in kHz)
1598 * @cpu: CPU number
1599 *
1600 * Get the CPU current (static) CPU frequency
1601 */
1602unsigned int cpufreq_get(unsigned int cpu)
1603{
1604 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1605 unsigned int ret_freq = 0;
1606
1607 if (policy) {
1608 down_read(&policy->rwsem);
1609 ret_freq = __cpufreq_get(cpu);
1610 up_read(&policy->rwsem);
1611
1612 cpufreq_cpu_put(policy);
1613 }
1614
1615 return ret_freq;
1616}
1617EXPORT_SYMBOL(cpufreq_get);
1618
1619static struct subsys_interface cpufreq_interface = {
1620 .name = "cpufreq",
1621 .subsys = &cpu_subsys,
1622 .add_dev = cpufreq_add_dev,
1623 .remove_dev = cpufreq_remove_dev,
1624};
1625
1626/*
1627 * In case platform wants some specific frequency to be configured
1628 * during suspend..
1629 */
1630int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1631{
1632 int ret;
1633
1634 if (!policy->suspend_freq) {
1635 pr_err("%s: suspend_freq can't be zero\n", __func__);
1636 return -EINVAL;
1637 }
1638
1639 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1640 policy->suspend_freq);
1641
1642 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1643 CPUFREQ_RELATION_H);
1644 if (ret)
1645 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1646 __func__, policy->suspend_freq, ret);
1647
1648 return ret;
1649}
1650EXPORT_SYMBOL(cpufreq_generic_suspend);
1651
1652/**
1653 * cpufreq_suspend() - Suspend CPUFreq governors
1654 *
1655 * Called during system wide Suspend/Hibernate cycles for suspending governors
1656 * as some platforms can't change frequency after this point in suspend cycle.
1657 * Because some of the devices (like: i2c, regulators, etc) they use for
1658 * changing frequency are suspended quickly after this point.
1659 */
1660void cpufreq_suspend(void)
1661{
1662 struct cpufreq_policy *policy;
1663
1664 if (!cpufreq_driver)
1665 return;
1666
1667 if (!has_target())
1668 return;
1669
1670 pr_debug("%s: Suspending Governors\n", __func__);
1671
1672 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1673 if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
1674 pr_err("%s: Failed to stop governor for policy: %p\n",
1675 __func__, policy);
1676 else if (cpufreq_driver->suspend
1677 && cpufreq_driver->suspend(policy))
1678 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1679 policy);
1680 }
1681
1682 cpufreq_suspended = true;
1683}
1684
1685/**
1686 * cpufreq_resume() - Resume CPUFreq governors
1687 *
1688 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1689 * are suspended with cpufreq_suspend().
1690 */
1691void cpufreq_resume(void)
1692{
1693 struct cpufreq_policy *policy;
1694
1695 if (!cpufreq_driver)
1696 return;
1697
1698 if (!has_target())
1699 return;
1700
1701 pr_debug("%s: Resuming Governors\n", __func__);
1702
1703 cpufreq_suspended = false;
1704
1705 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
1706 if (cpufreq_driver->resume && cpufreq_driver->resume(policy))
1707 pr_err("%s: Failed to resume driver: %p\n", __func__,
1708 policy);
1709 else if (__cpufreq_governor(policy, CPUFREQ_GOV_START)
1710 || __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))
1711 pr_err("%s: Failed to start governor for policy: %p\n",
1712 __func__, policy);
1713
1714 /*
1715 * schedule call cpufreq_update_policy() for boot CPU, i.e. last
1716 * policy in list. It will verify that the current freq is in
1717 * sync with what we believe it to be.
1718 */
1719 if (list_is_last(&policy->policy_list, &cpufreq_policy_list))
1720 schedule_work(&policy->update);
1721 }
1722}
1723
1724/**
1725 * cpufreq_get_current_driver - return current driver's name
1726 *
1727 * Return the name string of the currently loaded cpufreq driver
1728 * or NULL, if none.
1729 */
1730const char *cpufreq_get_current_driver(void)
1731{
1732 if (cpufreq_driver)
1733 return cpufreq_driver->name;
1734
1735 return NULL;
1736}
1737EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1738
1739/*********************************************************************
1740 * NOTIFIER LISTS INTERFACE *
1741 *********************************************************************/
1742
1743/**
1744 * cpufreq_register_notifier - register a driver with cpufreq
1745 * @nb: notifier function to register
1746 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1747 *
1748 * Add a driver to one of two lists: either a list of drivers that
1749 * are notified about clock rate changes (once before and once after
1750 * the transition), or a list of drivers that are notified about
1751 * changes in cpufreq policy.
1752 *
1753 * This function may sleep, and has the same return conditions as
1754 * blocking_notifier_chain_register.
1755 */
1756int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1757{
1758 int ret;
1759
1760 if (cpufreq_disabled())
1761 return -EINVAL;
1762
1763 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1764
1765 switch (list) {
1766 case CPUFREQ_TRANSITION_NOTIFIER:
1767 ret = srcu_notifier_chain_register(
1768 &cpufreq_transition_notifier_list, nb);
1769 break;
1770 case CPUFREQ_POLICY_NOTIFIER:
1771 ret = blocking_notifier_chain_register(
1772 &cpufreq_policy_notifier_list, nb);
1773 break;
1774 default:
1775 ret = -EINVAL;
1776 }
1777
1778 return ret;
1779}
1780EXPORT_SYMBOL(cpufreq_register_notifier);
1781
1782/**
1783 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1784 * @nb: notifier block to be unregistered
1785 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1786 *
1787 * Remove a driver from the CPU frequency notifier list.
1788 *
1789 * This function may sleep, and has the same return conditions as
1790 * blocking_notifier_chain_unregister.
1791 */
1792int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1793{
1794 int ret;
1795
1796 if (cpufreq_disabled())
1797 return -EINVAL;
1798
1799 switch (list) {
1800 case CPUFREQ_TRANSITION_NOTIFIER:
1801 ret = srcu_notifier_chain_unregister(
1802 &cpufreq_transition_notifier_list, nb);
1803 break;
1804 case CPUFREQ_POLICY_NOTIFIER:
1805 ret = blocking_notifier_chain_unregister(
1806 &cpufreq_policy_notifier_list, nb);
1807 break;
1808 default:
1809 ret = -EINVAL;
1810 }
1811
1812 return ret;
1813}
1814EXPORT_SYMBOL(cpufreq_unregister_notifier);
1815
1816
1817/*********************************************************************
1818 * GOVERNORS *
1819 *********************************************************************/
1820
1821/* Must set freqs->new to intermediate frequency */
1822static int __target_intermediate(struct cpufreq_policy *policy,
1823 struct cpufreq_freqs *freqs, int index)
1824{
1825 int ret;
1826
1827 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1828
1829 /* We don't need to switch to intermediate freq */
1830 if (!freqs->new)
1831 return 0;
1832
1833 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1834 __func__, policy->cpu, freqs->old, freqs->new);
1835
1836 cpufreq_freq_transition_begin(policy, freqs);
1837 ret = cpufreq_driver->target_intermediate(policy, index);
1838 cpufreq_freq_transition_end(policy, freqs, ret);
1839
1840 if (ret)
1841 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1842 __func__, ret);
1843
1844 return ret;
1845}
1846
1847static int __target_index(struct cpufreq_policy *policy,
1848 struct cpufreq_frequency_table *freq_table, int index)
1849{
1850 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1851 unsigned int intermediate_freq = 0;
1852 int retval = -EINVAL;
1853 bool notify;
1854
1855 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1856 if (notify) {
1857 /* Handle switching to intermediate frequency */
1858 if (cpufreq_driver->get_intermediate) {
1859 retval = __target_intermediate(policy, &freqs, index);
1860 if (retval)
1861 return retval;
1862
1863 intermediate_freq = freqs.new;
1864 /* Set old freq to intermediate */
1865 if (intermediate_freq)
1866 freqs.old = freqs.new;
1867 }
1868
1869 freqs.new = freq_table[index].frequency;
1870 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1871 __func__, policy->cpu, freqs.old, freqs.new);
1872
1873 cpufreq_freq_transition_begin(policy, &freqs);
1874 }
1875
1876 retval = cpufreq_driver->target_index(policy, index);
1877 if (retval)
1878 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1879 retval);
1880
1881 if (notify) {
1882 cpufreq_freq_transition_end(policy, &freqs, retval);
1883
1884 /*
1885 * Failed after setting to intermediate freq? Driver should have
1886 * reverted back to initial frequency and so should we. Check
1887 * here for intermediate_freq instead of get_intermediate, in
1888 * case we have't switched to intermediate freq at all.
1889 */
1890 if (unlikely(retval && intermediate_freq)) {
1891 freqs.old = intermediate_freq;
1892 freqs.new = policy->restore_freq;
1893 cpufreq_freq_transition_begin(policy, &freqs);
1894 cpufreq_freq_transition_end(policy, &freqs, 0);
1895 }
1896 }
1897
1898 return retval;
1899}
1900
1901int __cpufreq_driver_target(struct cpufreq_policy *policy,
1902 unsigned int target_freq,
1903 unsigned int relation)
1904{
1905 unsigned int old_target_freq = target_freq;
1906 int retval = -EINVAL;
1907
1908 if (cpufreq_disabled())
1909 return -ENODEV;
1910
1911 /* Make sure that target_freq is within supported range */
1912 if (target_freq > policy->max)
1913 target_freq = policy->max;
1914 if (target_freq < policy->min)
1915 target_freq = policy->min;
1916
1917 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1918 policy->cpu, target_freq, relation, old_target_freq);
1919
1920 /*
1921 * This might look like a redundant call as we are checking it again
1922 * after finding index. But it is left intentionally for cases where
1923 * exactly same freq is called again and so we can save on few function
1924 * calls.
1925 */
1926 if (target_freq == policy->cur)
1927 return 0;
1928
1929 /* Save last value to restore later on errors */
1930 policy->restore_freq = policy->cur;
1931
1932 if (cpufreq_driver->target)
1933 retval = cpufreq_driver->target(policy, target_freq, relation);
1934 else if (cpufreq_driver->target_index) {
1935 struct cpufreq_frequency_table *freq_table;
1936 int index;
1937
1938 freq_table = cpufreq_frequency_get_table(policy->cpu);
1939 if (unlikely(!freq_table)) {
1940 pr_err("%s: Unable to find freq_table\n", __func__);
1941 goto out;
1942 }
1943
1944 retval = cpufreq_frequency_table_target(policy, freq_table,
1945 target_freq, relation, &index);
1946 if (unlikely(retval)) {
1947 pr_err("%s: Unable to find matching freq\n", __func__);
1948 goto out;
1949 }
1950
1951 if (freq_table[index].frequency == policy->cur) {
1952 retval = 0;
1953 goto out;
1954 }
1955
1956 retval = __target_index(policy, freq_table, index);
1957 }
1958
1959out:
1960 return retval;
1961}
1962EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1963
1964int cpufreq_driver_target(struct cpufreq_policy *policy,
1965 unsigned int target_freq,
1966 unsigned int relation)
1967{
1968 int ret = -EINVAL;
1969
1970 down_write(&policy->rwsem);
1971
1972 ret = __cpufreq_driver_target(policy, target_freq, relation);
1973
1974 up_write(&policy->rwsem);
1975
1976 return ret;
1977}
1978EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1979
1980/*
1981 * when "event" is CPUFREQ_GOV_LIMITS
1982 */
1983
1984static int __cpufreq_governor(struct cpufreq_policy *policy,
1985 unsigned int event)
1986{
1987 int ret;
1988
1989 /* Only must be defined when default governor is known to have latency
1990 restrictions, like e.g. conservative or ondemand.
1991 That this is the case is already ensured in Kconfig
1992 */
1993#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1994 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1995#else
1996 struct cpufreq_governor *gov = NULL;
1997#endif
1998
1999 /* Don't start any governor operations if we are entering suspend */
2000 if (cpufreq_suspended)
2001 return 0;
2002
2003 if (policy->governor->max_transition_latency &&
2004 policy->cpuinfo.transition_latency >
2005 policy->governor->max_transition_latency) {
2006 if (!gov)
2007 return -EINVAL;
2008 else {
2009 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
2010 policy->governor->name, gov->name);
2011 policy->governor = gov;
2012 }
2013 }
2014
2015 if (event == CPUFREQ_GOV_POLICY_INIT)
2016 if (!try_module_get(policy->governor->owner))
2017 return -EINVAL;
2018
2019 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
2020 policy->cpu, event);
2021
2022 mutex_lock(&cpufreq_governor_lock);
2023 if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
2024 || (!policy->governor_enabled
2025 && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
2026 mutex_unlock(&cpufreq_governor_lock);
2027 return -EBUSY;
2028 }
2029
2030 if (event == CPUFREQ_GOV_STOP)
2031 policy->governor_enabled = false;
2032 else if (event == CPUFREQ_GOV_START)
2033 policy->governor_enabled = true;
2034
2035 mutex_unlock(&cpufreq_governor_lock);
2036
2037 ret = policy->governor->governor(policy, event);
2038
2039 if (!ret) {
2040 if (event == CPUFREQ_GOV_POLICY_INIT)
2041 policy->governor->initialized++;
2042 else if (event == CPUFREQ_GOV_POLICY_EXIT)
2043 policy->governor->initialized--;
2044 } else {
2045 /* Restore original values */
2046 mutex_lock(&cpufreq_governor_lock);
2047 if (event == CPUFREQ_GOV_STOP)
2048 policy->governor_enabled = true;
2049 else if (event == CPUFREQ_GOV_START)
2050 policy->governor_enabled = false;
2051 mutex_unlock(&cpufreq_governor_lock);
2052 }
2053
2054 if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
2055 ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
2056 module_put(policy->governor->owner);
2057
2058 return ret;
2059}
2060
2061int cpufreq_register_governor(struct cpufreq_governor *governor)
2062{
2063 int err;
2064
2065 if (!governor)
2066 return -EINVAL;
2067
2068 if (cpufreq_disabled())
2069 return -ENODEV;
2070
2071 mutex_lock(&cpufreq_governor_mutex);
2072
2073 governor->initialized = 0;
2074 err = -EBUSY;
2075 if (__find_governor(governor->name) == NULL) {
2076 err = 0;
2077 list_add(&governor->governor_list, &cpufreq_governor_list);
2078 }
2079
2080 mutex_unlock(&cpufreq_governor_mutex);
2081 return err;
2082}
2083EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2084
2085void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2086{
2087 int cpu;
2088
2089 if (!governor)
2090 return;
2091
2092 if (cpufreq_disabled())
2093 return;
2094
2095 for_each_present_cpu(cpu) {
2096 if (cpu_online(cpu))
2097 continue;
2098 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
2099 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
2100 }
2101
2102 mutex_lock(&cpufreq_governor_mutex);
2103 list_del(&governor->governor_list);
2104 mutex_unlock(&cpufreq_governor_mutex);
2105 return;
2106}
2107EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2108
2109
2110/*********************************************************************
2111 * POLICY INTERFACE *
2112 *********************************************************************/
2113
2114/**
2115 * cpufreq_get_policy - get the current cpufreq_policy
2116 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2117 * is written
2118 *
2119 * Reads the current cpufreq policy.
2120 */
2121int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2122{
2123 struct cpufreq_policy *cpu_policy;
2124 if (!policy)
2125 return -EINVAL;
2126
2127 cpu_policy = cpufreq_cpu_get(cpu);
2128 if (!cpu_policy)
2129 return -EINVAL;
2130
2131 memcpy(policy, cpu_policy, sizeof(*policy));
2132
2133 cpufreq_cpu_put(cpu_policy);
2134 return 0;
2135}
2136EXPORT_SYMBOL(cpufreq_get_policy);
2137
2138/*
2139 * policy : current policy.
2140 * new_policy: policy to be set.
2141 */
2142static int cpufreq_set_policy(struct cpufreq_policy *policy,
2143 struct cpufreq_policy *new_policy)
2144{
2145 struct cpufreq_governor *old_gov;
2146 int ret;
2147
2148 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2149 new_policy->cpu, new_policy->min, new_policy->max);
2150
2151 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2152
2153 if (new_policy->min > policy->max || new_policy->max < policy->min)
2154 return -EINVAL;
2155
2156 /* verify the cpu speed can be set within this limit */
2157 ret = cpufreq_driver->verify(new_policy);
2158 if (ret)
2159 return ret;
2160
2161 /* adjust if necessary - all reasons */
2162 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2163 CPUFREQ_ADJUST, new_policy);
2164
2165 /* adjust if necessary - hardware incompatibility*/
2166 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2167 CPUFREQ_INCOMPATIBLE, new_policy);
2168
2169 /*
2170 * verify the cpu speed can be set within this limit, which might be
2171 * different to the first one
2172 */
2173 ret = cpufreq_driver->verify(new_policy);
2174 if (ret)
2175 return ret;
2176
2177 /* notification of the new policy */
2178 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2179 CPUFREQ_NOTIFY, new_policy);
2180
2181 policy->min = new_policy->min;
2182 policy->max = new_policy->max;
2183
2184 pr_debug("new min and max freqs are %u - %u kHz\n",
2185 policy->min, policy->max);
2186
2187 if (cpufreq_driver->setpolicy) {
2188 policy->policy = new_policy->policy;
2189 pr_debug("setting range\n");
2190 return cpufreq_driver->setpolicy(new_policy);
2191 }
2192
2193 if (new_policy->governor == policy->governor)
2194 goto out;
2195
2196 pr_debug("governor switch\n");
2197
2198 /* save old, working values */
2199 old_gov = policy->governor;
2200 /* end old governor */
2201 if (old_gov) {
2202 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
2203 up_write(&policy->rwsem);
2204 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2205 down_write(&policy->rwsem);
2206 }
2207
2208 /* start new governor */
2209 policy->governor = new_policy->governor;
2210 if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
2211 if (!__cpufreq_governor(policy, CPUFREQ_GOV_START))
2212 goto out;
2213
2214 up_write(&policy->rwsem);
2215 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
2216 down_write(&policy->rwsem);
2217 }
2218
2219 /* new governor failed, so re-start old one */
2220 pr_debug("starting governor %s failed\n", policy->governor->name);
2221 if (old_gov) {
2222 policy->governor = old_gov;
2223 __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
2224 __cpufreq_governor(policy, CPUFREQ_GOV_START);
2225 }
2226
2227 return -EINVAL;
2228
2229 out:
2230 pr_debug("governor: change or update limits\n");
2231 return __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2232}
2233
2234/**
2235 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2236 * @cpu: CPU which shall be re-evaluated
2237 *
2238 * Useful for policy notifiers which have different necessities
2239 * at different times.
2240 */
2241int cpufreq_update_policy(unsigned int cpu)
2242{
2243 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2244 struct cpufreq_policy new_policy;
2245 int ret;
2246
2247 if (!policy)
2248 return -ENODEV;
2249
2250 down_write(&policy->rwsem);
2251
2252 pr_debug("updating policy for CPU %u\n", cpu);
2253 memcpy(&new_policy, policy, sizeof(*policy));
2254 new_policy.min = policy->user_policy.min;
2255 new_policy.max = policy->user_policy.max;
2256 new_policy.policy = policy->user_policy.policy;
2257 new_policy.governor = policy->user_policy.governor;
2258
2259 /*
2260 * BIOS might change freq behind our back
2261 * -> ask driver for current freq and notify governors about a change
2262 */
2263 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2264 new_policy.cur = cpufreq_driver->get(cpu);
2265 if (WARN_ON(!new_policy.cur)) {
2266 ret = -EIO;
2267 goto unlock;
2268 }
2269
2270 if (!policy->cur) {
2271 pr_debug("Driver did not initialize current freq\n");
2272 policy->cur = new_policy.cur;
2273 } else {
2274 if (policy->cur != new_policy.cur && has_target())
2275 cpufreq_out_of_sync(cpu, policy->cur,
2276 new_policy.cur);
2277 }
2278 }
2279
2280 ret = cpufreq_set_policy(policy, &new_policy);
2281
2282unlock:
2283 up_write(&policy->rwsem);
2284
2285 cpufreq_cpu_put(policy);
2286 return ret;
2287}
2288EXPORT_SYMBOL(cpufreq_update_policy);
2289
2290static int cpufreq_cpu_callback(struct notifier_block *nfb,
2291 unsigned long action, void *hcpu)
2292{
2293 unsigned int cpu = (unsigned long)hcpu;
2294 struct device *dev;
2295
2296 dev = get_cpu_device(cpu);
2297 if (dev) {
2298 switch (action & ~CPU_TASKS_FROZEN) {
2299 case CPU_ONLINE:
2300 __cpufreq_add_dev(dev, NULL);
2301 break;
2302
2303 case CPU_DOWN_PREPARE:
2304 __cpufreq_remove_dev_prepare(dev, NULL);
2305 break;
2306
2307 case CPU_POST_DEAD:
2308 __cpufreq_remove_dev_finish(dev, NULL);
2309 break;
2310
2311 case CPU_DOWN_FAILED:
2312 __cpufreq_add_dev(dev, NULL);
2313 break;
2314 }
2315 }
2316 return NOTIFY_OK;
2317}
2318
2319static struct notifier_block __refdata cpufreq_cpu_notifier = {
2320 .notifier_call = cpufreq_cpu_callback,
2321};
2322
2323/*********************************************************************
2324 * BOOST *
2325 *********************************************************************/
2326static int cpufreq_boost_set_sw(int state)
2327{
2328 struct cpufreq_frequency_table *freq_table;
2329 struct cpufreq_policy *policy;
2330 int ret = -EINVAL;
2331
2332 list_for_each_entry(policy, &cpufreq_policy_list, policy_list) {
2333 freq_table = cpufreq_frequency_get_table(policy->cpu);
2334 if (freq_table) {
2335 ret = cpufreq_frequency_table_cpuinfo(policy,
2336 freq_table);
2337 if (ret) {
2338 pr_err("%s: Policy frequency update failed\n",
2339 __func__);
2340 break;
2341 }
2342 policy->user_policy.max = policy->max;
2343 __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
2344 }
2345 }
2346
2347 return ret;
2348}
2349
2350int cpufreq_boost_trigger_state(int state)
2351{
2352 unsigned long flags;
2353 int ret = 0;
2354
2355 if (cpufreq_driver->boost_enabled == state)
2356 return 0;
2357
2358 write_lock_irqsave(&cpufreq_driver_lock, flags);
2359 cpufreq_driver->boost_enabled = state;
2360 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2361
2362 ret = cpufreq_driver->set_boost(state);
2363 if (ret) {
2364 write_lock_irqsave(&cpufreq_driver_lock, flags);
2365 cpufreq_driver->boost_enabled = !state;
2366 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2367
2368 pr_err("%s: Cannot %s BOOST\n",
2369 __func__, state ? "enable" : "disable");
2370 }
2371
2372 return ret;
2373}
2374
2375int cpufreq_boost_supported(void)
2376{
2377 if (likely(cpufreq_driver))
2378 return cpufreq_driver->boost_supported;
2379
2380 return 0;
2381}
2382EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
2383
2384int cpufreq_boost_enabled(void)
2385{
2386 return cpufreq_driver->boost_enabled;
2387}
2388EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2389
2390/*********************************************************************
2391 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2392 *********************************************************************/
2393
2394/**
2395 * cpufreq_register_driver - register a CPU Frequency driver
2396 * @driver_data: A struct cpufreq_driver containing the values#
2397 * submitted by the CPU Frequency driver.
2398 *
2399 * Registers a CPU Frequency driver to this core code. This code
2400 * returns zero on success, -EBUSY when another driver got here first
2401 * (and isn't unregistered in the meantime).
2402 *
2403 */
2404int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2405{
2406 unsigned long flags;
2407 int ret;
2408
2409 if (cpufreq_disabled())
2410 return -ENODEV;
2411
2412 if (!driver_data || !driver_data->verify || !driver_data->init ||
2413 !(driver_data->setpolicy || driver_data->target_index ||
2414 driver_data->target) ||
2415 (driver_data->setpolicy && (driver_data->target_index ||
2416 driver_data->target)) ||
2417 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2418 return -EINVAL;
2419
2420 pr_debug("trying to register driver %s\n", driver_data->name);
2421
2422 if (driver_data->setpolicy)
2423 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2424
2425 write_lock_irqsave(&cpufreq_driver_lock, flags);
2426 if (cpufreq_driver) {
2427 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2428 return -EEXIST;
2429 }
2430 cpufreq_driver = driver_data;
2431 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2432
2433 if (cpufreq_boost_supported()) {
2434 /*
2435 * Check if driver provides function to enable boost -
2436 * if not, use cpufreq_boost_set_sw as default
2437 */
2438 if (!cpufreq_driver->set_boost)
2439 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2440
2441 ret = cpufreq_sysfs_create_file(&boost.attr);
2442 if (ret) {
2443 pr_err("%s: cannot register global BOOST sysfs file\n",
2444 __func__);
2445 goto err_null_driver;
2446 }
2447 }
2448
2449 ret = subsys_interface_register(&cpufreq_interface);
2450 if (ret)
2451 goto err_boost_unreg;
2452
2453 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
2454 int i;
2455 ret = -ENODEV;
2456
2457 /* check for at least one working CPU */
2458 for (i = 0; i < nr_cpu_ids; i++)
2459 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
2460 ret = 0;
2461 break;
2462 }
2463
2464 /* if all ->init() calls failed, unregister */
2465 if (ret) {
2466 pr_debug("no CPU initialized for driver %s\n",
2467 driver_data->name);
2468 goto err_if_unreg;
2469 }
2470 }
2471
2472 register_hotcpu_notifier(&cpufreq_cpu_notifier);
2473 pr_debug("driver %s up and running\n", driver_data->name);
2474
2475 return 0;
2476err_if_unreg:
2477 subsys_interface_unregister(&cpufreq_interface);
2478err_boost_unreg:
2479 if (cpufreq_boost_supported())
2480 cpufreq_sysfs_remove_file(&boost.attr);
2481err_null_driver:
2482 write_lock_irqsave(&cpufreq_driver_lock, flags);
2483 cpufreq_driver = NULL;
2484 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2485 return ret;
2486}
2487EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2488
2489/**
2490 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2491 *
2492 * Unregister the current CPUFreq driver. Only call this if you have
2493 * the right to do so, i.e. if you have succeeded in initialising before!
2494 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2495 * currently not initialised.
2496 */
2497int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2498{
2499 unsigned long flags;
2500
2501 if (!cpufreq_driver || (driver != cpufreq_driver))
2502 return -EINVAL;
2503
2504 pr_debug("unregistering driver %s\n", driver->name);
2505
2506 subsys_interface_unregister(&cpufreq_interface);
2507 if (cpufreq_boost_supported())
2508 cpufreq_sysfs_remove_file(&boost.attr);
2509
2510 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
2511
2512 down_write(&cpufreq_rwsem);
2513 write_lock_irqsave(&cpufreq_driver_lock, flags);
2514
2515 cpufreq_driver = NULL;
2516
2517 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2518 up_write(&cpufreq_rwsem);
2519
2520 return 0;
2521}
2522EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2523
2524static int __init cpufreq_core_init(void)
2525{
2526 if (cpufreq_disabled())
2527 return -ENODEV;
2528
2529 cpufreq_global_kobject = kobject_create();
2530 BUG_ON(!cpufreq_global_kobject);
2531
2532 return 0;
2533}
2534core_initcall(cpufreq_core_init);
Linux 6.x block layer and io_uring tree(s)